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Note: This is a sub-section of 1937 Institution of Mechanical Engineers
The first part of the works was built in 1878 on part of a 40-acre site adjacent to road, railway, and canal, and an additional 81 acres between the canal and another railway was acquired in 1921 for future extension. Production and purification of coal gas is divided into three self-contained sections, two of which may be combined if required.
No. 1 section carbonizing plant consists of eight settings, each containing eight 33-inch x 10-inch vertical retorts adapted for steaming and having a daily capacity of 2,250,000 cu. ft. of gas of 450 B.Th.U. per cu. ft. calorific value. Steam for the retorts is provided by two Cochran boilers 6 ft. 6 in. diameter x 15 feet high. Coal is delivered on an elevated rail gantry and is tipped by rotary tippler to a chute feeding a coal breaker, the crushed coal then being elevated and tipped into 50-ton storage bunkers by a gravity bucket conveyer. Coke from the retorts is discharged cool into skips mounted on bogies, which are wheeled to the yard to be picked up by a 3-ton steam crane. The crane travels on a reinforced concrete gantry and tips the coke into either of two hoppers supplying rotary coke screens mounted above a set of reinforced concrete coke hoppers of 200 tons capacity.
No. 2 section carbonizing plant has seven settings each containing eight 33-inch x 10-inch vertical steaming retorts, with a total capacity of 3,500,000 cu. ft. of gas per day. The coal-handling plant includes a capstan wagon-hauling system on an elevated gantry inside the retort house, a rotary wagon tippler, a coal breaker of the claw type with a reciprocating tray feed to band conveyers, which in turn deliver to a lip bucket conveyer (capacity 70 tons per hour) supplying overhead storage bunkers of capacity equivalent to 48 hours' supply of coal. Coke is discharged from the retorts into a travelling chute which delivers the coke to a lip bucket conveyer encircling the retort bench. The conveyer is arranged to discharge the coke either into a hopper for supplying producer fuel or on to band conveyers running overhead from the retort house to the coke-screening plant. This consists of two rotary screens mounted on 200-ton reinforced concrete coke hoppers. "Debreezing" screens are fitted in all the coke chutes and a portable vibrating screen can be arranged to separate the breeze and dust. The screens may be bypassed and coke from the retort house tipped from the band conveyers to a flying hopper supplying an automatic telpher skip filler. A telpher system is employed for stacking coke in the yard store. All coal- and coke-handling plant is electrically driven and is duplicated in entirety. The waste gases from the settings are collected in brick-lined steel ducts and pass through either of two Spencer-Bonecourt horizontal multi-tubular waste-heat boilers 8 feet in diameter and 18 feet long, each capable of evaporating 8,000 lb. of water per hour. The gases are drawn through the settings, flues, and boilers by fans electrically driven, mounted on top of the boilers.
No. 3 section carbonizing plant consists of two benches each containing four settings of eight 50-inch x 10-inch vertical steaming retorts. The total capacity is 5,000,000 cu. ft. of gas per day. The coal- and coke-handling plant is similar to that of No. 2 section, but of greater capacity. There are three waste-heat boilers, each 7 feet in diameter and 18 feet long and capable of evaporating 8,000 lb. of water per hour, when utilizing the waste gases from one bench only. In this case the induced draught fans are driven by steam turbines through reduction gears. The boilers of Nos. 2 and 3 sections are interconnected and a 7-inch diameter steam main connects the works boilers to the waste-heat boilers. The works boilers are arranged in two batteries of three Lancashire boilers, interconnected to supply steam to exhausters, washing plant, pumps, compressors, and gasholders.
Electricity at 220 volts (direct current) is generated in a power house adjacent to the retort house, utilizing waste-heat steam at 120 lb. per sq. in. pressure in any of four 75 h.p. vertical twin-cylinder non-compound high-speed steam engines direct-coupled to 50 kW. compound-wound open type generators. The engines are designed to exhaust at a back pressure of 25-30 lb. per sq. in. to a low-pressure main supplying steam to the retorts. Two standby generators, each giving an output of 53 kW. at 220 volts, are direct-coupled to 90 h.p. horizontal single-cylinder gas engines. There are two switchboards, each with two generator panels, and one six-circuit feeder panel, the mains from which supply the whole of the works.
The gas-condensing plant consists of three batteries of vertical water-cooled condensers 7 ft. 7 in. diameter x 27 feet high, and three sets of cast iron atmospheric condensers. Exhausting plant is housed in two engine rooms, one containing three four-blade exhausters of 115,000 cu. ft. per hour capacity driven by horizontal single-cylinder double-acting steam engines, and the other containing three similar sets each of 200,000 cu. ft. per hour capacity. Tar is removed from the gas by Livesey washers fixed after the exhausters, the capacities ranging from 2 to 5 million cu. ft. per day. There are four tower scrubbers, 12 feet diameter x 58 feet high, and two smaller tower scrubbers, all board-filled; three Feld vertical centrifugal washers, driven by single-cylinder steam engines, one similar washer driven by electric motor, and one vertical reciprocating tray washer driven by a steam engine. Oxide purification is carried out in four sets of boxes having water lute sealed covers and arranged with catch boxes, and two sets of four boxes with dry-sealed lids without catch boxes.
All the coal gas is measured by six drum type station meters of capacities from 60,000 to 100,000 cu. ft. per hour. The meter outlets are connected to a 36-inch diameter main common to five gasholder inlets. There are two column-guided two-lift gasholders each of 1,500,000 cu. ft. capacity in brick tanks 172 ft. 6 in. diameter x 35 ft. 6 in. deep; one two-lift gasholder of 2,250,000 cu. ft. capacity; and one three-lift gasholder of 3,330,000 cu. ft. capacity in twin brick tanks 200 feet diameter x 38 ft. 3 in. deep. The latest gasholder, of 5,000,000 cu. ft. capacity, has four lifts spirally guided in a steel tank 213 feet diameter x 41 ft. 6 in. deep on a reinforced concrete foundation.
Carburetted water gas is manufactured in a large building incorporating boiler house, engine room, generator house, and coke stores and equipped with elevators and conveyers extending over the stores and supply hoppers. The generating plant consists of one completely automatic plant with a capacity of 2,250,000 cu. ft. per day, equipped with mechanical grate, annular generator boiler, waste-heat boiler, and grit arresters; there are also two hand-operated machines. Air blast is supplied by two fans, each capable of delivering 15,000 cu. ft. of air per minute, direct-coupled to 114 h.p. steam turbines. The steam supply from the waste-heat boilers is augmented by any of four Lancashire boilers equipped with turbine furnaces, superheaters, and economizers.
The gas from the machines passes through three water-cooled condensers and four vertical scrubbers to a two-lift relief gasholder of 182,000 cu. ft. capacity, in a steel tank. Two four-blade steam-driven exhausters force the gas through a set of seven purifiers 32 feet square x 6 feet deep, fitted with water lute sealed covers, the first two being filled with graded coke and the remainder with oxide. Water gas is separately measured in a rotary meter of 200,000 cu. ft. hourly capacity, and then passes to the gasholder inlet main to mix with the coal gas stream. Oil for carburetting purposes is stored in a steel tank 51 feet diameter x 31 ft. 6 in. deep contained in a concrete catch tank.
Tar and ammoniacal liquor from the coal gas plant are collected in six 50-foot diameter cast iron tanks for delivery to the chemical works, where up to 10 tons of sulphate of ammonia are manufactured daily. Sulphur is recovered in a Claus kiln and the effluent from the ammonia stills is decanted to separate the sludge and is stored in a cast iron tank for delivery to the sewers. Tar is distilled for the light oils and for the preparation of road tar.
Three vertical steam-driven tandem compound gas compressors, each capable of compressing 3,500 cu. ft. of gas per minute to 10 lb. per sq. in. pressure, are employed for supplying a high-pressure feeder main encircling the district. A machine shop and smiths' shop are equipped to deal with all maintenance work and much of the new constructional work for the whole department. Carpenters and wheelwrights are housed in a shop equipped with woodworking and pattern-making machinery. A stove repair shop with incinerator, caustic tanks, shot-blast cleaning plant, spraying booths, drilling, grinding, and screwing machines, deals with 300 stoves per week.
The sale of gas for the year 1936 was 2,572,000,000 cu. ft., of which 22 per cent was for industrial purposes. The area of supply is approximately 145.5 square miles and is supplied by 604 miles of mains from 4 inches to 36 inches diameter. The population within the area is 257,000, and the number of gas consumers is 92,000. The area of supply includes several outlying villages which are connected direct to the works through individual governors, or to a high-pressure feeder main through district governors. The main supplies to the town are through 36-inch and 24-inch trunk mains from Aylestone Road and Belgrave Gate Works respectively, with branch mains of varying sizes arranged on the arterial system. A 12-inch high-pressure main circles the town to augment the supply to any area, through district governors, at periods of maximum demand. This main is also connected to the smaller works in the Belgrave Gate district so that gas can be interchanged from either works when found necessary.
Electricity generation and distribution in Leicester first commenced under the control of the Gas Department and the first generating station was built in the Aylestone Gas Works and commenced to supply power in 1894. This station was intended to meet demands for electric lighting, and generated single-phase alternating current at 2,000 volts. In 1904 a second generating station was built to supply direct current at 500 volts to the city tramways, but it was found convenient to connect private consumers who required power for driving electric motors, and a large industrial load was built up. To secure co-ordination of supply the two generating stations were placed under one committee in 1911, but such was the increase in demand for electricity after the War, that it became evident that these two stations could not cope with the demand even if completely rebuilt.
The present station was, therefore, commenced in 1922 on a site sufficiently large to permit extensions to cope with increase in demand for many years, and to enable the existing stations to be closed. The concentration of generation in one station also facilitated reorganization of the distribution system, and a radial system with 6,600-volt distributing mains was commenced. The station was therefore called the "Central Generating Station". After the passing of the Electricity Act, 1926, the station became a selected station for generating electricity to the requirements of the Central Electricity Board, and it is now usually called the Freemen's Meadow Generating Station. Whilst the station has now become an important unit in the grid system, its principal function is still that of supplying the City of Leicester with the whole of its electricity requirements.
General Layout. The station is built alongside the canalized river Soar which provides water for condensing purposes, but owing to the small flow, cooling towers are necessary to dissipate the bulk of the waste heat. The site is almost level, and at a depth of approximately 10 feet there occurs a stratum of limestone shale, capable of carrying building and plant foundations without expensive reinforcement by piling or concrete rafts.
Fuel supplies are obtained from Leicestershire collieries approximately 10 miles from the city, and are conveyed to sidings alongside the station. On the sidings are one double- and one single-truck tippler feeding belt conveyers which transport the coal to the boiler house bunkers or to the ground storage. Between the sidings and the station is ground storage for approximately 15,000 tons of coal.
The coal kept in storage is of "good" quality, as the low-grade coal normally burnt in the station cannot safely be stored owing to risk of spontaneous combustion. Coal is reclaimed from the store by travelling cranes which deliver to the belt conveyers. The belt conveyers are interconnected so that either of the boiler houses may be fed. At the point of inter-connexion is a dust separator in which unscreened slack may be pneumatically separated into "fine" and "coarse" slacks respectively, suitable for pulverized fuel and mechanical stoker firing. The coal handling arrangements permit coaling of the station from incoming coal trains or from store at a rate of 150 tons per hour.
Boiler House. The first half of No. 1 boiler house was built in 1922 and the second half in 1924. The building holds four Babcock and Wilcox and four Vickers boilers, each of a capacity of 45,000 lb. per hour, equipped with chain-grate stokers. Since erection, these boilers have been altered by the addition of air preheaters and cyclone dust collectors.
No. 2 boiler house was built in 1929 and equipped with three boilers by Messrs. International Combustion, Ltd., each of a capacity of 150,000 lb. per hour, arranged for pulverized fuel firing. A further unit with a capacity of 175,000 lb. per hour was set to work in 1935.
A third boiler house is projected, to hold two boilers similar in design to the last-mentioned type. The latest boiler is an excellent example of modern boiler design for consuming a low-grade fuel (approximately 9,500 B.Th.U. per lb.) with maximum evaporative capacity and thermal efficiency. The combustion chamber is fired by eight pulverized-fuel burners, placed in the corners so as to permit the furnace walls to be completely lined with bare water tubes; the bottom is protected by a double screen of water tubes. At the top of the furnace the gases pass through boiler and superheater without baffling, to an economizer of the steaming type, and thence through duplicate air preheaters to the induced draught fan. In spite of the high proportion of ash in the coal, the boiler may be steamed for thousands of hours without "slagging" or "birdnesting" in the furnace or boiler tubes.
The induced draught fan, forced draught fan, and the burner feeder motors are driven by variable-speed alternating-current commutator motors, and allow very flexible control of the steaming rate. This boiler and the others in this house are connected to a system of automatic control, which continuously adjusts the speeds of coal feeders and fans so as to maintain steam demand with maximum combustion efficiency.
Milling of the pulverized fuel is done in the boiler house basement by mills arranged on a "bin and feeder" system. Each boiler is equipped with a 15-ton mill complete with gas piping, exhauster, cyclone, collector, and storage bin. The mills are run at full output, whatever the load on the boiler, and are stopped when the storage bins are full. A screw conveyer connects the discharge from each of the mill cyclones so that any bin may be filled from either mill. Each pulverized fuel bin has a number of rotary feeders in its base from which the fuel is conveyed by air to the burners of its particular boiler.
Turbo-Alternator Plant. The station was originally planned to hold a maximum of five main generators, two of 10,000 kW. and three of 15,000 kW. capacity, but since the advent of the national grid, sizes have been increased. The capacities of the machines are as follows: No. 1 (installed 1922), 10,000 kW.; No. 2 (installed 1924; rebuilt 1931), 14,000 kW.; No. 3 (installed 1927), 18,750 kW.; No. 4 (installed 1929), 25,000 kW.; and No. 5 (on order), 30,000 kW. There are also two house service sets of 500 and 1,500 kW. respectively.
Nos. 1 and 3 turbines are designed for steam at 250 lb. per sq. in. and 700 deg. F. total temperature, and are bled for feed water heating to 180 deg. F. Nos. 2 and 4 turbines are designed for steam at 350 lb. per sq. in. and 750 deg. F. total temperature, and are bled for feed water heating to 300 deg. F. No. 2 turbine is a pass-out machine and steam is taken from it for sale to a nearby factory. Approximately 120,000,000 lb. of steam is sold per annum, and conveyed through pipes over a distance of approximately 1 mile. The heat losses in transport amount to approximately 3 per cent and about half the condensate is returned to the generating station. This is an example of public steam supply which shows great saving to both the consumers and suppliers. Make-up feed water is obtained from the town water mains, and approximately half is fed to the boilers untreated, and half evaporated in three high-pressure evaporators of the thermo-compression type.
Condenser Cooling Water. Each condenser is equipped with two circulating pumps, which draw from a concrete flume running alongside cooling towers and are connected at one end to the river through revolving screens and duplicate intake pipes. The pumps discharge to a "bus pipe" feeding the cooling towers and connected at one end to discharge pipes leading to the river. Control valves are arranged so that the quantity of water withdrawn from the river may be regulated to suit the available flow. Even at periods of no flow in the river, up to 15,000 kW. can be carried by the natural cooling of the river basin. The cooling towers are of the natural draught type having a reinforced concrete shell and wooden internal cooling stack; and each tower is designed to cool 700,000 gallons of water per hour through 12 deg. F.
Switchgear. Power is generated and distributed from the station at 6,600 volts, three-phase, with a frequency of 50 cycles per second, but owing to the large currents involved, No. 5 turbo-generator and any future machines will generate at 33,000 volts. The main busbars and circuit breakers are housed in two separate switch houses at a short distance from the main buildings, and all switches are remote-controlled from a control room overlooking the turbine room. The main busbars in each switch house are divided into two sections, and tie bars are provided so that the four separate sections may be coupled through current-limiting reactors. A reserve busbar serves the whole of the switchgear for use in emergency.
No. 1 switch house is equipped with the cellular type of switchgear, and No. 2 switch house with metal-clad switchgear. Both types of switchgear have circuit breakers capable of rupturing 750,000 kVA. From these switch houses outgoing feeders go to primary substations placed in different parts of the city. Each primary substation is made as far as possible of a standard size, fed by two pairs of cables, and each switch house is connected to the grid through a transformer. All primary substations have connecting cables, so a very complete system of duplicate supply exists to ensure continuity of supply even if important gear fails. The switch houses are of fireproof construction and are provided with a battery of carbon dioxide cylinders for fire extinction.
Rotary House Substation. A primary substation is placed inside the generating station for supplying the immediately adjacent area. It is equipped with oil-less switchgear having circuit breakers of the "water expansion" type. These circuit breakers, though popular in Germany and on the Continent generally, are rarely seen in this country.
Maintenance Shop. The repair workshop is well equipped with machine tools and is capable of dealing with the maintenance of the whole of the plant.
Garage, Stores, and Domestic Workshop. Extensive and well equipped buildings adjacent to the generating station are provided for housing motor transport, for general and mains stores, and for domestic apparatus stores and workshops. These are general activities of the Department, but are of special interest because of the remarkable development of distribution and of domestic load in Leicester during the last ten years.
The water supply of the City of Leicester, like that of many of our large cities, has had a varied history. It is possible that the Roman settlement of Ratae, on the site of which Leicester now stands, was publicly supplied with water. Ancient water pipes have been found when excavating for new mains, many being made of earthenware surrounded by lime concrete. The house or other connexions were of cast lead pipe cemented into special earthenware connecting pipes. These are believed to be seventeenth-century work. The extent of this system is not known, but there is ample evidence that the town was chiefly supplied by draw wells and pump wells until 1841, when the population had risen to 50,806. Owing to the increased population and the demand for water, and to the fact that some of the existing sources of supply had become unsatisfactory, a company was formed to investigate the water supplies in the district, and eventually, upon the advice of the late Thomas Hawksley, M.I.Mech.E., an application was made to Parliament for powers to construct the Thornton Reservoir and Works. The result was that an "Act for better supplying with water the inhabitants of the Borough of Leicester and certain parishes and places adjacent thereto in the County of Leicester" received Royal Assent on the 22nd July 1847.
The Thornton waterworks were completed in 1854. The source of supply consists of the rainfall on a drainage area of 2,860 acres, collected and stored in a reservoir containing 311,000,000 gallons. The water is slowly filtered through sand beds and collected in a pure-water tank from which it flows by gravitation to New Parks Service Reservoir (capacity 2,000,000 gallons) and thence to distribution. There are five filter beds with a total area of 3,587 square yards.
The supply of pure water was greatly appreciated and the "water population" rapidly increased. The company, finding that their resources were becoming again exhausted, made application to Parliament and obtained an Act in 1866 for the construction of the Cropston Reservoir. These works were completed and opened in 1870. The source of supply is the rainfall collected from a drainage area of 4,400 acres, the contents of the reservoir being 556,000,000 gallons. The water is passed through sand filters and pumped from the pure water tanks to the service reservoirs. From thence it gravitates into the distribution system. The pumping plant at Cropston consists of two installations, the first of which was laid down on the completion of the works in 1870 and comprises two Wolf beam pumping engines and four Cornish boilers. These engines normally run at 15 r.p.m. and pump 80 gallons per revolution each against a head of 135 feet. The second installation comprises a triple-expansion direct-acting pumping engine of the marine type built by Messrs. Easton and Anderson of Erith, with two Lancashire boilers. This engine is capable of pumping about 1,000,000 gallons in 12 hours, and normally runs at 25 r.p.m., delivering 56 gallons per revolution against a head of 240 feet.
The whole undertaking was acquired by the Corporation in 1878, when the water population was 100,172 persons and the consumption per head per day for all purposes was 25.23 gallons. At that time, when very little of the city's sewage was water-borne and when a bath was not considered an absolute necessity in every house, this was undoubtedly a very high consumption per head, and pointed to a large amount of unnecessary waste. The Corporation, therefore, passed by-laws and regulations and established a system of waste inspection, the effect of these measures being to reduce the consumption per head from 25.23 gallons in 1878 to 16.24 in 1893.
In 1894 the Swithland Reservoir works were completed. These works collect the rainfall from a drainage area of 3,500 acres, the contents of the reservoir being 490,000,000 gallons, with filter beds 9,846 square yards in area. The plant at this station consists of three triple-expansion direct-acting pumping engines, capable of pumping 2,600,000 gallons in 24 hours against a head of 280 feet. The growth of the city at this time was so fast that in 1898, only four years after the completion of Swithland reservoir, it was found necessary to seek further Parliamentary powers in order to obtain a supply from the River Derwent in Derbyshire. Other towns sought similar powers and many conferences took place. Ultimately, an arrangement was arrived at, whereby a joint Bill for obtaining Derwent Valley water was laid before the House. This Bill, which in due course became law, provided for a scheme under which the water from the upper reaches of the Rivers Derwent and Ashop were apportioned amongst the four Corporations of Leicester, Derby, Nottingham, and Sheffield, provision being also made for Derby and Nottingham Counties. Leicester is the predominant partner with a share of 35.72 per cent.
Two masonry dams were constructed and two reservoirs formed in the Derwent Valley with a combined capacity of 4,100,000,000 gallons. These, together with the various aqueducts, formed the first portion of the works, which was completed in 1912. Not many years later, Sheffield, and then Nottingham, gave notice to the Board that they required all the water to which they were entitled from the whole scheme. The Board had, therefore, immediately to proceed with further works to supply the quantities needed. The second portion of the works, completed in 1927, consists of a tunnel from the Ashop Valley to the Derwent Valley, turning the water from the River Ashop into the Derwent Reservoir.
Early in 1934, Leicester and Derby gave notice that they required their full shares and so the third portion, the building of the Ladybower Dam up to a level of 128 feet above the level of the stream, is now in course of construction. This reservoir will have a capacity of 5,000,000,000 gallons.
The filters at Bamford are only designed to take out the grosser impurities and do not remove the peaty colour from the water. When, therefore, the water arrives at Hallgates it is put through mechanical pressure filters, in which it is rendered colourless and alkaline, thus making the water suitable for manufacturing and drinking purposes and preventing any possibility of plumbosolvency. There are at present 68 of these filters and a further 28 are now being installed. The arrangements for adding the chemicals necessary for the filtering process and the lime water after filtration are automatic. Sight bowls show at a glance the effect of the process and the pH (hydrogen ion) value of the water sent out is automatically recorded.
The area of Leicester's authorized limits of supply is 111,866 acres (the area within the city boundaries being 16,979 acres) and 650 miles of mains are in use, supplying 98,000 houses In addition to supplying water within the authorized area, a supply in bulk is also given to the Borough of Nuneaton, and to parts of Barrow on Soar and Castle Donington Rural Districts. The supply to Nuneaton is pumped at Desford pumping station to Tuttle Hill reservoir, Nuneaton, by an electrically driven centrifugal pump with Diesel plant as standby, through a 14-inch diameter pumping main, Nuneaton giving a supply in bulk to Hinckley from the main en route. The total population supplied is now estimated to be 384,421.
The College of Arts and Crafts was inaugurated in 1870, while the College of Technology came into being about 1880, in the form of a few science classes held at the old Wyggeston School, High Cross Street. It was later moved into a house in St. Martin's, where, it is recorded, certain teachers conveyed their machines and apparatus to and from the school in a hand truck. The present buildings occupy a complete island site bounded by the Newarke, Asylum Street, and Richmond Street. The final extensions are now being completed at a cost of £86,000.
The College of Technology comprises Schools of Engineering, Commerce, Boot and Shoe Manufacture, Textiles, Chemistry and Dyeing, Pharmacy, and Applied Science. The School of Engineering caters for mechanical, civil, electrical, and automobile and aviation engineering students. There are laboratories for strength of materials, heat engines, hydraulics, automobile engineering, electrical engineering, and metallurgy. The strength of materials laboratory is one of the finest in the country and is used as a regional test house for industrial testing. There are also workshops for electric-arc and oxy-acetylene welding, foundry work, heat treatment, production engineering, electrical installation work, gas fitting, and pipe bending.
The School is recognized for course work for the B.Sc. (Engineering) Degree of the University of London, and for Ordinary and Higher National Certificates in Mechanical and Electrical Engineering. It is also recognized for National Certificates in Chemistry, Building, and Textiles, and for endorsed Certificates in Commerce.
There are about 2,500 students on the roll of the College of Technology, of whom the School of Engineering claims between 700 and 800. There are also about 1,800 students attending the College of Arts and Crafts. Other activities in the Colleges include courses in hosiery manufacture, bakery, retail trades, architecture and building, painting and decorating, plumbing, printing and book production, fine arts, women's crafts, etc.
This firm of printers was founded over 100 years ago in Great Tower Street, London, and has continued in the same family until the present time. In 1907 an amalgamation was arranged with Edward Shardlow and fresh premises were taken at Newarke Street, Leicester, the London works remaining at 72, Chiswell Street, E.C.2. In the last ten years the plant has been entirely reorganized to cope with the best quality commercial printing.
In the letterpress section most of the machines are of the two-revolution type, fitted with stream feeders and sprayers. The latter are to dry the printed sheet, an operation which is especially necessary when printing three-colour process work. The sizes of the machines range from 20 x 25 inches to 36 x 46 inches, and each one is driven by a separate motor. For the smaller class of letterpress, fully automatic machinery, capable of a very large output, is used.
The lithographic section consists of single- and two-colour machines, the latter printing two colours in one operation. These machines are automatically fed by the stream type of feeder. The process used is generally direct photography on to sensitized zinc plate, but hand drawing may also be employed if the work is suitable. The machines print sheets up to 34 x 45 inches.
The bindery contains several types of interesting machinery for cutting, folding, and stitching.
The company, which has manufactured and carried out for the past fifty years heating, ventilation, and other domestic engineering installations, has works situated near the city boundary. They include an iron foundry which supplies a considerable variety of castings, both machine- and hand-moulded, up to 5 tons in weight, principally for manufacturers of machine tools, Diesel engines, rolling mill machinery, etc.; also brass and non-ferrous castings of all descriptions.
The company also manufactures an automatic boiler stoker and steam cooking apparatus of all kinds. Another product is a semi-rotary hand pump; the department in which it is made is organized for mass-production. Half the output of this article is exported. Other manufactures include calorifiers, trap valves, and other appliances connected with heating installations.
The works cover 4 acres in all.
The firm was founded in 1910 by Mr. P. A. Bentley, M.I.Mech.E. At that time the firm was styled "The Earth-Driven Clock Company" and was engaged in the manufacture of earth-driven clocks and scientific instruments, which were invented by Mr. Bentley in 1911. During the manufacture of earth-driven clocks, the pedograde machine, which was patented by Mr. Harry Church, was redesigned and perfected in 1912-14. The manufacture of this instrument called for modern methods of production and scientific construction, among which was the provision of a Vernier scale reading. The importance of three-point contacts was also realized. The machine was employed for accurate measurements of feet to provide data to determine the measurements of footwear. At that time Mr. Bentley also designed a magneto with magnets so arranged that a much greater spark was produced than hitherto.
At the beginning of the War in 1914 the firm was engaged in research for the production of accurate screw gauges, work which required the solution of many scientific and mathematical problems of an entirely new character. Having perfected the means of production of the gauges, the firm concentrated on the actual production of both male and female screw gauges, which were used in all branches of munitions production for the Army, Navy, and Air Force; the company was employed on this work up to the last year of the War. Consultations were held at the National Physical Laboratory, Teddington, to enable corrections to be carried out to a high degree of accuracy.
In connexion with this work, which confirmed the great accuracy of the gauge system, it was found necessary to introduce a new system for checking not only dimensions, but also shapes and forms of all types of threads. This method was the means of introducing the projection system of shadow values, which again entailed the solution of many problems and much perseverance, before it was perfected. In 1916 the name of the firm was changed to its present form, and larger and more up-to-date premises were obtained. Mr. Bentley subsequently introduced a seamless-rib, fully automatic hose, half-hose, and sock machine, which did much to enhance the firm's reputation. The success of the hosiery machine again made it necessary to secure larger premises. In 1934 the business was made into a private limited liability company, and two years ago the business of Messrs. T. Grieve and Company, Ltd., was purchased, for the purpose of manufacturing hosiery latch needles.
The designing office, also the heat-treatment methods and the general layout and organization of the works are of special interest. The works are divided into two large rooms, covering an area of 40,000 sq. ft. One shop is laid out as the machine shop, and in the other the hosiery machines are assembled. There are 60 different models, ranging from 2.5 needles to the inch to 22 needles to the inch.
After the machines have been assembled, they are first mechanically tested, then finally tested for producing the article in ribbed footwear for which they have been designed, before dispatch.
The company was formed in 1899 by the amalgamation of Messrs. Pearson and Bennion Ltd., Leicester, engineers, with the British interests of the International Goodyear Shoe Machinery Company, and of the Consolidated and McKay Lasting Machine Company, in alliance with the United Shoe Machinery Company of America. The building — Union Works — originally occupied by Messrs. Pearson and Bennion became the new company's headquarters, and early activities were mainly concentrated upon producing a limited range of machines used in the manufacture of boots and shoes.
A further important amalgamation took place in 1930 when the extensive interests of the Gimson Shoe Company were joined to those of the present firm. The company produces to-day more than 300 different types of machines. In addition to the machinery produced in Union Works, other factories make components used in the manufacture of boots and shoes, known as toe puffs, counters, and shanks, in enormous quantities, together with other shoe trade accessories, such as nails, rivets, heel pins, screwed wire, sandpaper cones and moulded coils, sandpaper bands and sheets, wood and steel shoe racks, and fittings of every description used in the shoe industry.
To-day the works are the most extensive of their kind in Europe, occupying a total floor area of over 500,000 sq. ft. They stand on over 25.25 acres of ground, and extend from front to back to a distance of 0.33 mile. The original building of Messrs. Pearson and Bennion, which had a floor area of approximately 80,000 sq. ft., is now devoted solely to office accommodation. The total number of employees at the firm's fourteen depots, has risen from 200 in 1899, to 3,000, of whom more than 400 have been continuously employed by the company for over 25 years.
Union Works. The main workshop is located here and is used almost exclusively for the manufacture of machinery. While the major portion of the machinery manufactured is for use in the shoemaking industry, the company also manufactures machinery for the saddlery and harness, leather goods, rubber, printing and allied trades.
The main workshops are constructed in modern style and consist of five floors, the first three of which are 60 feet wide and the upper two 40 feet wide. The first four of these floors are 500 feet long and the fifth is 320 feet long. The sides of the factory are 80 per cent of glass and are equipped with ample means of ventilation. The main floors are free from structural obstructions such as staircases, toilets, and strong rooms. These are carried in abutting arms connected to the main floors by corridors, leaving the full width and length free for manufacture.
The works are divided departmentally as follows. Raw material is housed in departments adjacent to the main factory and divided into two sections - steel stores and casting stores. From these the manufacturing departments are fed with raw materials, which progress from east to west along the main building. At the eastern end are situated the machine shops, and at the extreme western end are the assembling departments which are in turn followed, after bridging a public road, by (1) the machine warehouse, (2) the parts warehouse, and (3) the packing shop.
The machine shops are classified according to their operations, automatics, screw machines, turret lathes, heavy milling, heavy turning, planing, gear-cutting and milling, drilling, grinding, turning, and parts fitting. In addition to these departments there are various experimental departments, a tool room for jigs and fixtures, and a small tools department for gauges, taps, reamers, etc.
The assembling departments are generally classified according to shoe machinery operation, and are known as lasting, goodyear, finishing, and metallic departments.
When machines are ready for dispatch they are stocked in a four-story warehouse with a total floor area of 24,000 sq. ft. This is connected to the two top floors of the main workshop by means of a two-story totally enclosed bridge. The four floors are served by a 3-ton electric lift, situated in the centre of the building, and also by a 3-ton electric transporter hoist, situated directly over the loading dock on the ground floor. A new warehouse was built towards the end of 1935, immediately adjoining the machinery warehouse, to hold the stock of machine parts. This building is four stories high and is built of reinforced concrete. The building and all the equipment are fireproof, and the whole is isolated from the other warehouse by means of automatically closing fireproof steel sliding doors. Each of the three upper floors of this warehouse is constructed to carry a weight of 1,800 tons. Each floor is 200 feet by 60 feet, and there are 90,000 sq. ft. of steel shelving to accommodate the 7,500,000 machine parts held in stock.
Two power houses supply part of the power and lighting requirements, which are augmented by a bulk supply at high tension. The east power house is equipped with three Lancashire boilers 8 ft. 6 in. in diameter by 30 feet long, working at 140 lb. per sq. in. pressure, and fitted with mechanical stokers. There are three 100 kW. high-speed generators, and one 300 kW. generator driven by a Corliss engine. The fuel consumption of the three boilers is 100 tons per week. The plant in the west power house consists of two boilers, similar to those of the east power house, consuming 60 tons of coal per week; there are two 100 kW. high-speed generators, one 300 kW. turbo-generator, one 100 kW. motor-generator, and one 150 kW. rotary converter. The annual output of the two power houses is 2,000,000 units.
Invention and Development. To stimulate the development of the machinery produced by the company, the work is subdivided into sections. Inventors occupy themselves with specific problems, and pass their work on to the designing office, from whose drawings the initial machine or machines are made. When the model is approved, a separate drawing office prepares working drawings; the planning office prepares operations, and a tool drawing office the necessary jigs and fixtures. During the period between the approval of the model and the completion of the full range of jigs and fixtures secondary experimental departments manufacture a limited number of the machines, until the provision of suitable tools allows of the machine forming part of the regular factory production. There is also a large staff of experts in shoemaking whose services are available not only to the company but to its customers.
Equipment and System. The machine shops are equipped with some 1,500 machines which are progressively being provided with individual electrical drive, thus improving the lighting by eliminating belt shadows.
Transport throughout the works is carried out by hand and battery trucks. The floors of the main buildings are of rock maple, giving a suitable surface for this method of transport. A system of works transfer allows the most insignificant part to be located, and its advance throughout its various operations to be ascertained at any time during the working day by reference to the records. Labels of different colour are employed to denote the starting period of an order; these labels accompany the parts through the works, so that those concerned may readily detect work which is lagging.
The pattern shop provides for the manufacture of patterns in both wood and iron. As the castings must be eventually located in fixtures for machining they are of very accurate dimensions and finish. The company does not maintain its own foundry, but obtains the castings required from a local foundry. Almost all the steel used in the machine parts is made to the company's own specification.
The Union Works laboratory, hardening, and inspection departments are all under one control. The laboratory is essentially equipped as a materials testing, rather than a chemical, laboratory. The equipment comprises a range of microscopes suitable for photographic records, a 60,000 lb. Olsen tensile and compression testing machine, single and continuous impact testing machines, and a spring-testing machine. Apparatus for hardness tests includes Brinell, Rockwell, and Vickers hardness testing machines, and a scleroscope rebound testing machine, while a complete duplicate set of pyrometers recording the temperatures of all the hardening furnaces, etc., is also installed.
The equipment of the different inspection groups on the various floors varies with the class of work inspected, and includes dial-reading micrometers, vernier gauges, and Prestwich gauges in which a column of liquid varies in height by 1 inch for each thousandth of an inch variation in the part being tested.
Hardening Department. This department is located in a single-story building adjacent to the laboratory in the main workshop. The equipment includes electric, gas, coal, and oil-fired furnaces for hardening, tempering, and heat-treating machine parts, cutters, and tools of all kinds. The electrically heated equipment consists of resistance furnaces for hardening small parts, and an automatically controlled resistance furnace for case-hardening machine parts made of "Nitralloy" steel. Such parts are hardened by the nitration process. An electric tempering furnace is fitted with automatic temperature control, for tempering hardened parts to remove brittleness. Gas-fired equipment includes furnaces for hardening high-speed tool steels, lead baths for local hardening, and cyanide baths for surface hardening.
Both gas and oil-fired furnaces are installed for carburizing and annealing purposes, also a gas-fired rotary furnace, in which a mixture of oil and ammonia gas is utilized for carburizing. Two quenching tanks used in connexion with the rotary furnace contain oil and brine respectively and are over 7 feet deep. The contents of these and other similar tanks in the department are kept in constant circulation from the main supply tanks to ensure rapid and even cooling.
All furnaces are fitted with pyrometric control, platinum-rhodium thermocouples being used, connected to suspended-coil temperature indicators carried on concrete pedestals to eliminate vibration. These indicators are all connected in duplicate to an automatic recorder in the laboratory.
There is also a trichlorethylene gas degreasing tank for removing oil from oil-quenched parts preparatory to sandblasting.
Separate factories exist for the manufacture of accessories to the trades which the company serves. Certain of these factories are situated on land adjoining Union Works, whilst others exist as subsidiary companies in other locations in Leicester and other parts of England. Those adjoining Union Works are the "IVI" works, the knife and cutter, shank and counter, toe puff, rack, and roll works.
IVI Works (Tack and Nail Factory). The manufacture of tacks and nails was first undertaken by the company 29 years ago in Northampton, when 15 machines were installed and 7 people employed. The works were moved to Leicester in 1908, but the growth of the business necessitated moving in 1912 to the present "IVI" works, which then had a total floor area of 29,195 sq. ft. To-day it is the largest factory of its kind in the world, with a floor area of 76,766 sq. ft. Upwards of 902 machines are employed, and in 1936, 39,865,477,000 tacks and nails were produced. The employees number 328. All raw material used is of British manufacture and made to the company's specifications. The machinery employed is all of the company's own design and manufacture.
The tacks, nails, and rivets produced in this factory have to be accurately and uniformly made. They must run in a regular flow down chutes or raceways and pass with certainty through the separating means on shoemaking machines. Over 500 different kinds of steel and brass tacks, nails, and rivets are manufactured, ranging from minute "micro lasting" tacks, 56,000 of which go to the pound, to heel-attaching nails 2 inches long.
Knife and Cutter Factory. In this model factory - by far the largest of its kind in the country - are manufactured press knives and cutters for use in almost every trade. The materials which these knives and cutters have to cut include cotton linings, leather, silk, celluloid, fibre board, brake lining material, rubber, and paper. Knives and cutters are manufactured from bar steel, and from solid steel blanks, or from a combination of the two, according to the shape of the knife or cutter and the work for which it is required.
If a knife is made from bar steel, a suitable bar is cut to the requisite measurement by a shearing machine. It is then forwarded either to the knife-bending department or to the smithy, where it is bent or forged to an accurately formed metal template previously prepared from the pattern, and the two ends are welded together in an electric welding machine. The knife or cutter is then sent to the heat-treating department for normalizing. It then proceeds to the machine shop to be ground parallel on both top and bottom edges. The sides next receive attention, being first closely milled to the outline required, and then finished to the exact shape by hand filing.
The shaping of a knife or cutter made from a solid blank of steel in the first instance proceeds on rather different lines. The solid blank of steel is roughly cut to shape by the oxygen cutting machine. The required shape is then scribed out on the blank from the metal template before the blank proceeds to the machine shop, where it is dealt with in much the same way as the knife or cutter made from bar steel, except that the superfluous metal from the inside of the knife is removed by drilling, shaping, and slotting machines, preparatory to milling. Hardening and tempering then follow. The knife or cutter is then polished, whetted and tested, preparatory to packing and dispatching.
Special Features of the Works. There are two works fire brigades, which have won notable successes in several competitions. The fire-prevention appliances throughout the works are very complete. There is also a fully equipped ambulance room. The works mess room has seating accommodation for over 400, and the employees have since 1911 enjoyed the benefit of an athletic ground 12 acres in extent; the athletic club membership is now 2,000.
The firm has been associated with the tyre trade for 31 years. From its inception it has aimed at the production of goods of uniform quality. In the present works is installed a unique system of control over quality which has been evolved and developed by the firm, and is aptly called the "electric eye." The principal manufacturing processes are rigidly controlled by this means and their operation recorded on paper charts. As an example, the time factor in connexion with the vulcanization of all the firm's products - ranging from small moulded goods to giant pneumatic tyres for commercial vehicles - is accurately recorded to within a limit of ±15 seconds.
In the works can be seen the building up by hand of the heavy foundations of the "Heavy Tread" car tyres and the subsequent fitting of the wide and deeply patterned tread which has been designed to give skid-resistance over the maximum mileage. A naphtha recovery plant operates at a high efficiency. The naphtha, which is used as a solvent to make the rubber semi-liquid so that it may be more easily forced into and between the cotton cords comprising the foundation fabric, is vaporized and eventually reconverted into the original fluid. Another feature is a unique type of vulcanizing press, designed by the firm, which vulcanizes two tyres at the same time whilst giving unit control over quality. Fully automatic, this double-decker type of press is controlled by a master clock which in turn is connected with the time-recording instruments forming an integral part of the "electric eye" system.
St. Margaret's Works is probably the largest self-contained hosiery factory in Great Britain. It stands on 5 acres of land and its floor space must be practically double this area. Over 3,700 operatives are employed and when the extensions now in hand are complete this number will be increased to 4,000. When the present works were built, in 1865, a beam engine was installed. It was made by Joseph Ryde and Gimson and Company, of Leicester, and was of the single-cylinder double-acting and condensing type, with one cylinder 30 inches in diameter and 5 ft. 6 in. stroke. For many years this engine drove the machinery in a room measuring 80 feet x 360 feet with an additional underground drive to two other rooms 80 feet x 100 feet, also a series of smaller rooms. The system comprised shaft and bevel drives, one of each pair of the bevel wheels having wooden teeth in order to reduce noise. This arrangement continued in the case of the largest room until 1931, when overhead electric motor drives were installed. In 1932 a 500-volt direct-current generator was attached to the engine, and this supplied the current for the overhead motors until 1936. During that year these motors were changed from 500-volt direct-current to suit 415-volt, three-phase alternating current. At the same time, in the case of the main room the overhead drives were replaced by small floor-drives. Altogether eight 30 h.p. motors using direct current at 500 volts were changed for 90 small three-phase motors of an equivalent total horse-power. A system extending through the whole of the works enables the current to be changed to the works motors, so that it can be supplied either from Leicester Corporation, the Belliss and Morcom plant, or the beam engine. Since the beam engine was installed in 1866 various parts have been renewed, but virtually this engine has been in constant operation for 70 years. The power generated amounts to 325 kW., the total consumption of the works being 825 kW. The difference (500 kW.) is supplied by Leicester Corporation. The lighting consumption is 200 kW. The small motor units in the factory drive 18 to 20 knitting machines. The sewing machine benches are also laid out with separate motors and drives to each bench, and each machine has its own lighting.
The steam consumption for the whole works is 32,000 lb. per hour. The greater part of the works is heated by the steam which is passed out from the Belliss and Morcom engine after leaving the intermediate-pressure cylinder, the pressure being no more than 5 lb. per sq. in. in the heating main.
The alternating current is 415 volts, 50 cycles, three-phase for power; and 240 volts, 50 cycles, single phase for lighting. All the twelve lifts (except one) are worked on 500 volts direct current. The 500-volt supply is generated in the daytime by the Belliss and Morcom engine; at night time it is rectified from the Corporation 415-volt three-phase supply by a mercury-arc bulb rectifier.
The steam for working the presses is supplied at a pressure of about 25 lb. per sq. in. There are three Lancashire boilers, each 28 feet long and 7 feet in diameter; one of them has a working pressure of 70 lb. per sq. in. and the other two 160 lb. per sq. in. There is also a small economic boiler capable of a pressure of 160 lb. per sq. in. These boilers are interconnected by a system of valves and can also be isolated at will. Altogether 100 men are employed on maintenance work. The canteens, which accommodate 500 employees, are provided with a hot water system for meals and washing purposes.
The production of biscuits in this modern factory is carried out under conditions of hygiene and efficiency. Automatic machinery largely contributes to these conditions, and a noteworthy feature is the installation in which biscuits are cut from continuous sheets of dough, passed on to a steel band, carried through the oven, and arranged on edge after baking in such a manner that the girl packers can lift quantities at one time with the minimum handling and the maximum speed. On other installations the biscuits may be moulded, cut off by means of a wire on being extruded through shaped dies, or they may issue from the machine in long ribbons to be cut into suitable lengths before being baked on a steel band.
Wrapping machines are in use to fix neat waxed and coloured paper wrappings round the packages of biscuits, and interesting automatic machines select biscuits from a hopper, place cream on them, place another biscuit on top of each and complete the delicacy known as a cream sandwich. For other types of biscuits with a laminated texture, the dough is rolled between rollers to a smooth even surface before being placed in the biscuit cutting machine.
The coating of certain types of biscuits with chocolate is done in a machine called a chocolate enrober. Biscuits pass through this machine to a continuous band cooler supplied with cold air, and emerge ready for packing. Mixing of dough takes place in powerful machines, incorporating large mixing tubs. The ovens are heated by gas, and all machines are electrically driven, each by its own motor.
The whole factory is laid out so that the flow is continuous from the store containing the flour and other ingredients to the dispatch of the finished goods on lorries.
The bakery takes its name from the neighbouring ruins of the old abbey where Cardinal Wolsey died on his way to London. The present company is the result of an amalgamation of the bread trade of Messrs. Frears, Ltd., with Messrs. Blacks Bread Company, in 1928. The bakery was built three years previously by the latter firm, which was founded in 1806. Considerable additions were made to the factory at the time of the amalgamation.
About forty-eight varieties of bread are produced daily in the bakery, as well as several kinds of cakes and confectionery. The flour room is at the top of the building, and sacks are raised by means of an elevator. A certain amount of heat is applied to the flour in this room, as it has been found to save hot water at a later stage. There are three hoppers in the floor, into which the flour is tipped, whence it proceeds through rotary-brush sifters into the round metal dough pans in which the mixing and kneading take place on the floor below. Strict control of the mixture is exercised; each dough is numbered and its history recorded. A physical test is made of every delivery of flour in order to decide what blends to use for different kinds of bread. Three bags of flour are emptied into the hopper, the blend depending upon the kind of bread to be made. Each removable pan of the mixers holds three bags of flour. Water is added from a tank attached to the mixer, in which the temperature is controlled at the level required.
It was found that if the employee's attention was withdrawn, too much water was occasionally added. To obviate this, Mr. Frears perfected a method by which a gauge in the tank is set at the amount of water to be added. Once the gauge is set, only the correct amount of water can enter the mixing pan. Another invention made by the company overcomes the danger of forgetting to lock the pan under the mixer. Previously when this happened, the pan was thrown to one side as soon as the electric motor started the mixing operation. The difficulty was overcome by fixing an electric contactor worked from the circumference of the pan, so that as soon as the pan moves from the centre, the motor stops.
Two hours after being mixed the dough passes to another identical mixer, but without a water tank. Here the final kneading takes place. The dough then passes through the divider and drops into linen bags, where it remains for ten minutes. By means of a spindle moulder the dough is next fashioned in the shape of a loaf; the machine can deal with either 1 lb. or 2 lb. loaves. Thence the dough passes along a conveyer and is filled into rows of tins, which when full pass on endless chains through a "prover". The tins of dough take 35 minutes on the journey through the prover, and then enter either of the swinging tray travelling ovens, where the baking takes 44 minutes.
There are two such ovens, one used exclusively for 2 lb. tin bread, and the other for various other kinds of bread. Bread to be wrapped is passed through the cooler for 1.75 hours, and is then either wrapped, or sliced and then wrapped. Bread which is not wrapped is placed on trays for cooling, which have been specially designed by the company. The bread rests on rounded wooden bars, and not on a flat bottom; this improves the cooling and the crust.
The cake bakery is a separate department, where rolls, buns, and various types of confectionery are made. The roll divider and moulder fashions the dough in the required shape at the rate of 4,000 rolls an hour. They then pass through the prover for three-quarters of an hour, and afterwards enter a gas-fired travelling oven on the same trays on which they passed through the prover.
The creaming, jamming, icing, and decorating of cakes and confectionery is done by girls working beside a moving conveyer. The confectionery is packed in cartons in the cake packing room. Transparent cellulose is largely used as a wrapping.
The company has preferred to develop its near business intensively rather than cover a very wide area. The largest radius covered is 25 miles from the bakery. For journeys of over 25 miles, motor vans are used, and electric battery vans for lesser distances. There is a group-charging plant for these vehicles, enabling them to "plug in" when they return from a journey and charge their batteries. The horse-drawn vehicle has been almost completely superseded by the electric van, forty of which are now in use. The interior of the vans is so constructed that the bread is slid in on loaded trays. This enables bread to be loaded fresh and avoids damage during delivery.
The firm's activities commenced in 1872, with the manufacture of electric bells, indicators, etc. To-day the scope of manufacture covers practically all small-current electrical apparatus. The products include bells, buzzers, and sound signals of all types, cased in wood, bakelite, or metal, together with all kinds of relays and bell indicators. The latter, which are widely used in hotels and offices, are installed on the Queen Mary, as is also the firm's system of luminous call for communication between passengers and steward or stewardess. The firm's mines signalling apparatus is used in almost every mine in this country. Another important product is a fire alarm system, which, for example, has been installed at the television broadcasting station at Alexandra Palace.
Another group of closely associated products are burglar and bank raid alarms. Electric motor syrens, which have come into prominence as air raid alarms, are also manufactured. These are extensively used for fire and other alarms and for "start" and "cease work" signals, and have been supplied to nearly all Air Ministry aerodromes. Liquid-level indicating, recording, and alarm apparatus is another product.
Intercommunication telephones for industrial and domestic purposes are also manufactured, in addition to an electric system for quickly locating members of staff in offices, stores, etc.
At present one of the busiest departments is that which manufactures electric clocks, both of the impulse type and the synchronous type. This side of the business not only embraces the manufacture of electric clocks from small sizes with 4-inch dials up to the largest turret clocks, but also includes electric striking and chiming mechanisms. The company was responsible for the design and manufacture of the largest true turret clock in the world, the Singer Clock on Clydebank, Scotland, which has a dial 3.5 feet greater in diameter than Big Ben. The firm also made what is probably the largest horizontal clock in the world, recently installed at the Rand Airport, South Africa.
The firm manufactures electrical apparatus to special requirements, such as special signalling systems, relay mechanisms, process-timing apparatus, and the like.
The company specializes in the manufacture of machinery used in stone quarries, gravel pits, etc., for crushing, grading, conveying, elevating, washing, drying, and for mixing with tar, bitumen, and cement for concrete. The works are situated about 0.75 mile from the centre of the city and include an iron foundry, which has a capacity for castings up to 12 tons in weight.
Opened in July 1936, this is one of the latest centres of its type set up by the Ministry of Labour for the purpose of training unemployed men chiefly drawn from distressed areas. The centre comprises light and airy workshops and trains students in both engineering and building trades. There is a machine shop, comprising about eighty machines, machine service department, and other equipment necessary for instruction in the various trades.
The present company was formed in 1908, to take over the previously existing Moya Typewriter Company, which had been manufacturing light-weight type-shuttle machines since 1902. The late Hidalgo Moya, who had been experimenting during this period, produced in the latter year the Imperial "model A." This was followed by a series of improved "three-bank" models, culminating in the radically different four-bank "model 50" in 1927. Since that date, "model 50" has been continuously improved, though in detail rather than design.
Of late years very rapid expansion has taken place. Whereas in 1931 the pay roll consisted of less than 500 persons, at present it stands at well over 1,300 and is still growing. Numerous extensions have been made to works and offices. The present administrative section and group of factories at North Evington comprise a floor area of more than 200,000 sq. ft., excluding the canteen and recreation room.
The work carried out in the factories is entirely specialized, the company's main products being the standard and portable typewriters; the only other manufacture is engineers' steel marking punches, which are a product of the type department. The machinery is chiefly of very specialized types, and many labour-saving and high-production methods have been introduced.
The main framework of a typewriter is of cast iron. The castings are not produced by the company, but a high degree of accuracy is required in the machining processes and the castings are very light. Castings are handled on a "line machining" principle, and although most of the machine tools are standard models they have in many cases been adapted to specialized machining. The jigs and fixtures in use in this department are interesting owing to the very light nature of many of the castings.
A large proportion of the parts of a typewriter are produced by press work. The press shop contains, among various up-to-date presses, a high-speed automatic press capable of producing up to 25,000 blanks per hour. In many of the press operations also a high degree of accuracy is obtained.
In the automatic screw machine shop, a large variety of small screws, pins, collars, and rivets are accurately produced on high-speed machines. There is also an automatic screw machine department, equipped with some of the latest high-speed screw machines and capstan lathes. The grinding department is equipped with light types of surface grinders and spindle grinders, most of which have been adapted to the special work on which they are employed. In this department a considerable amount of rubber grinding is also carried out. This is found to be the most satisfactory method of cutting rubber to accurate sizes, such as are necessary in the case of platen rollers. The plating and polishing shops contain plants for depositing chromium, nickel, cadmium, tin, etc. The milling shop affords some interesting examples of specialized machine tools, including rack cutters for cutting small toothed racks, which have been specially developed for the company's products. Probably the most interesting department is that in which typewriter type is manufactured. This, unlike printers' type, is not cast from type metal, but is cold-rolled from steel. In this department the complete manufacture of type is carried out, including the making of the drawings and "masters" from which the dies are engraved. The rolling machines are highly specialized and have been developed and made by the company.
Very many parts of a typewriter are case-hardened. The hardening shop is equipped with modern gas-fired sodium cyanide and other salt-bath furnaces, also with muffles and tempering baths for tool and gauge hardening. The enamelling plant which was recently installed is an example of continuous stove-enamelling. A very high finish is required on typewriter frames, and unusually careful precautions have to be taken to eliminate atmospheric dust, also oil and water, from the compressed air supplying the sprayers.
The company is the largest individual user of gas in the City of Leicester; gas is used for the hardening shop, the enamelling plant, and also for raising process steam. The company is also a large consumer of electricity; the whole plant is driven by electric motors, of which there are many hundreds, and all the more up-to-date machines are fitted with self-contained drives.
In the assembly shops a system of "line assembly" is carried out without the use of conveyers, yet with a high degree of efficiency. Some of the assembly jigs and fixtures and appliances are interesting examples of what is possible with a sufficiently specialized product.
In the works offices a very accurate system of production control is followed. The final product is dependent upon each of 2,000 or more parts reaching the assembly shop at the same time. The system in operation enables the office to know within a quarter of an hour the actual state of production of any part. When it is realized that this means the control of over 100,000 operations, it will be seen that the system has an exceedingly wide scope. The office block, erected in 1936, contains administrative and sales offices and a well-equipped drawing office.
The firm was established in Leicester in 1905 for the manufacture of small sensitive drilling machines. Since then it has been developed to include the manufacture of all modern types of drills, from super high-speed sensitive drills to heavy-duty vertical models with built-in motor drives. Precision grinding machines have been added to the firm's products, and this side of the business has grown from the manufacture of small tool and cutter grinders to include hydraulically controlled precision grinders and a wide variety of belt- and motor-driven models. Another manufacture is a range of twist-drill grinding machines. In addition the firm also specializes in engineers' small tools, including tool holders, sleeves, sockets, centre drills, and boring bars.
The plant includes an efficient battery of automatic machines for bar work. There is also a semi-automatic section, consisting chiefly of Ward capstan and Ward combination lathes for dealing with cast iron, brass, etc., in quantity. Among the latest additions to the machines are planers, jig borers, and a gear shaper. Fitting operations are carried out on the unit principle. Each operation is separately inspected whilst in progress, and every finished machine passes a most stringent test for accuracy and efficient working before dispatch.
The firm had its beginnings as far back as 1877, and is one of the oldest shoe-manufacturing firms in Leicester. Originally the style was Lennard and Wright, and later, Lennard Brothers, Ltd., the firm changing its title to Liberty Shoes, Ltd., in 1921. To-day the new factory (completed in 1921) consisting of four floors, built on the Hennibique reinforced concrete system, with a fine frontage to the eastern Boulevard, is capable of producing 15,000 pairs of women's footwear per week; only the medium and high-grade qualities are made.
The skins from which the shoe uppers are produced are still cut by hand; experience and skill are necessary to make the most of the leather, on account of great variations of texture, quality, and condition. Having been cut in what is known as the "clicking room", the uppers are then passed on to the closing, or machine, room, where they are stitched ready for lasting. They are then taken to the lasting department, where they are stretched over the wooden form, or last, for which they have been designed and cut. They are secured by numerous operations to the inner sole before the outer sole is attached, the bottom leather having in the meantime been prepared in another department. Heeling with either a built leather heel or Louis heel follows. The shoe is then ready for finishing, which consists in paring or trimming the edges and heels to the correct shape before the edges are set. The soles are coloured and polished, and subsequently pass on to the shoe-room, where the uppers are treed and dressed ready for boxing before dispatch.
Power is obtained from the Leicester Corporation three-phase alternating current at 415 volts, and serves some forty motors, ranging from 0.5 to 17.5 h.p. A mercury-arc rectifier supplies two lifts with direct current at 525 volts. There is also a dust-extraction plant, with a 15-foot fan driven by a 17.5 h.p. motor, coupled direct. Fractional horse-power motors, heating units, and lighting supply receive alternating current at 200 volts.
The company was founded nearly fifty years ago by Mr. George Perry as a patternmaking firm. Although it only employs some 80 men it is probably one of the largest pattern shops for the engineering trade in England.
The work is of a highly skilled type, wood being worked to less than 1/100 of an inch. Numerous orders are received from aircraft and marine engineering firms. Patterns are made for castings weighing from 1 oz. to 40 or 50 tons. The present works were built in 1930, and were specially designed for the firm's requirements. An exhibition of some very interesting patterns and castings will be on view.
Founded in 1911, the company specializes in the manufacture of drilling machinery, and the employees now number 300. Every type of drilling machine is made, the sizes ranging from a small bench machine, with a spindle speed of 15,000 r.p.m., to a heavy upright machine for drilling 3-inch holes out of the solid. The standard range of production also includes multiple-spindle machines of all types, radial drills, etc. Many types of single-purpose machines have been built, particularly for the automobile and allied trades. These machines are built up with automatic units, multiple heads, etc., arranged to operate simultaneously. Numerous extensions were made to the works between 1915 and 1934, and a further larger extension is being erected at the present time.
The business was started by Samuel Russell, Sen., in 1864 as a non-ferrous foundry and rapidly developed into a general iron foundry and engineering works, now employing about 500 hands. The specialities of the foundries are the production of grey iron castings for the shoe machinery and machine tool trades, and a wide range of modern alloy cast irons for high strength, and for heat- and corrosion-resisting purposes. The engineering department specializes in the manufacture of fully automatic hydraulically operated cold sawing machines.
At the Bath Lane works a great variety of castings, weighing from a few ounces to 5 tons each, is produced, mostly by hand methods. The plant includes a rotary furnace for special ferrous alloys, in addition to the usual cupola melting plant. Non-ferrous castings are also made here.
In the adjoining mechanical engineering works the latest developments in cold sawing machinery may be seen. The newest models include fully automatic metal-sawing machines, which are electrically and hydraulically operated and will saw any section of material into required lengths without the attention of an operator. A large variety of general engineering work is carried out here.
At the Bonchurch Street works there are two separate foundries, one for the production of small and medium size iron castings by various machine moulding methods. Generally, the quantities of castings made from each pattern are comparatively small, and many interesting methods have been adapted for cheap production within the limits imposed by the small quantities.
The second foundry is entirely new, and is equipped with the latest model of sand-slinger apparatus for the production of castings up to about 5 tons in weight. When this shop is in full operation it is expected that the total production from the various foundries will reach 100 tons per week. At these works, structural steelwork and a variety of fabricated steel products are made.
The business was established in 1886 to manufacture photographic lenses. The dry plate had been invented, and amateur photography was being developed. Up to that time the making of photographic lenses, by far the most accurate of all manufacturing processes, had employed very primitive appliances but much skill. The product was costly, and its quality varied greatly with the skill of the workers. Glasses were ground by hand on metal laps with loose abrasive, and were polished by hand. The metal mountings were made of cast brass rings and pieces of tubing which were screw-threaded by means of hand-chasers. Each part was fitted to its fellow and nothing was interchangeable.
When carborundum was first produced, the firm introduced bonded abrasive wheels in the grinding of lens surfaces and for grinding each peripheral edge on the common axis of the two finished surfaces, and made many similar improvements in the operations of lens making, all of which can be seen in the works.
In the last generation, nearly all important advances in the design of photographic lenses have been made in these works. Eighty per cent of all the lenses used in film studios are made at Leicester in addition to a large percentage of the best lenses for amateur cinematography, and most of the lenses used for photo-engraving, together with the prisms used for reversing the image. Lenses are made for astronomical and infra-red photography, for television, sound recording and for projection. The firm also makes lenses for quite cheap cameras, but all are of good quality. Lenses are made in quantities varying from 1 to 50,000 of one kind at a time, but all are made to prescribed tolerances and there is inspection independent of the operator after nearly every operation. Many of the methods of inspection will be of interest to engineers.
In making the mountings of lenses the firm in 1890 introduced interchangeability among screw threads. At that time there were no sufficiently accurate screw chasers, and no accurate means of measuring them. It was for this purpose that what are now known as needles and prisms were originated here for the trigonometrical measurement of screw threads, and limit-gauging was first applied to screws. It has been found practicable to generate and control the form of the thread chaser and guide screw with such accuracy that in shop practice it becomes unnecessary to gauge anything but the crest diameter of screws to ensure free interchangeability.
To engrave the lens mountings the Taylor-Hobson engraving machine was originated, and this has developed into a separate part of the business which is now divided about equally between optical and mechanical work.
The business is a private company, and there is an employees' co-partnership trust whose main object is to provide superannuation after the age of 65.
The late William Taylor, O.B.E., F.R.S., Hon. M.I.Mech.E. (Past-President), was the genius responsible for nearly all these fundamental improvements in mechanical design and methods of manufacture.
The factory was established in 1857 for the purpose of manufacturing elastic fabrics. The important constituent of these fabrics is the rubber thread, which is square in section and of various sizes. During recent years, however, a round thread has been inserted which has noteworthy physical properties. It is the rubber thread which determines in a large measure the physical properties of the finished goods. The other raw materials are cotton, artificial silk, and (in lesser quantities) real silk.
The raw materials arrive at the factory in hank form, and are then prepared for manufacture into elastic webs. The two distinct processes of manufacture are weaving and brading. In the weaving department, the narrow brace or suspender webs are made on multi-shuttle looms, whereas the wider corset fabrics are made on single-space high-speed looms. In the braiding department the machines are entirely different from the looms, and the process consists of a plaiting action as distinct from weaving. Narrow elastics are made in these machines, and are mainly supplied to the haberdashery trade.
The firm manufactures brace, garter, and suspender webs in plain and fancy pattern; narrow elastic for ladies' garments; and corset elastic, including the "two-way stretch" fabrics. There is in addition a special department in which elastic cords are made for the aircraft industry.
Due to the many special considerations involved in working wood, the mechanical problems arising in the manufacture of woodworking machinery are not less interesting than those connected with the production of precision machine tools, and call for highly specialized technical experience. Prominent among such considerations is the high speeds at which most modern types of woodworking machines operate. For example, high-speed planing and moulding demands running speeds for comparatively heavy cutter blocks of up to 7,200 r.p.m., while in high-speed routing speeds up to 24,000 r.p.m. are needed. Modern scientific production processes are thus essential to obtain true-running machines working at high speeds. Two other important points are the selection of the materials and the application of bearings. Another important factor is the multiplicity of machines used in the woodworking trades. At Green Lane Works over 80 different types and sizes are made. This wide range combined with the fact that most types are in steady and equal demand, presents unusual difficulties and calls for specialized methods of manufacture.
Although the firm was founded in 1897, the present works date back no more than fifteen years, and have recently been enlarged by an addition of 31,000 sq. ft. of productive floor space in the main engineering shops.
The machine shops have been completely electrified and individual electric drives to each machine applied throughout. All the electric power is supplied by Leicester Corporation Electricity Department and is three-phase alternating current at 415 volts, with a frequency of 50 cycles per second. In order to eliminate the difficulties experienced in connecting the leads to a large number of comparatively small motors, usual with individual electric-driven machine tools, power distribution from fuse boards has been displaced by a system of busbars extending down each bay, in almost the identical position of the former line-shafts. By this means all machines can be conveniently connected to a source of power immediately above them. It also allows additions or movements of machines, which may be necessitated by a change of routing of the work, to be made with the minimum of trouble.
The busbars are carried in steel trunking, and the connecting cables to each machine also run in this trunking to the nearest stanchion, from which they are taken down in conduits and run either under or along the floor to the respective motors. Complication of downward conduits is thus avoided, and the space round and above the machines is kept clear; moreover, additional working space is provided, and there is a minimum interference of light.
The main engineering shops are laid out in seven bays, all under one roof and on one floor, six bays being approximately 320 feet long and 30 feet wide, and one 100 feet long and 30 feet wide. Six of the seven bays are equipped with overhead electric cranes of the cage type, ranging in capacity from 2 to 5 tons. The floors in all the bays are of wood blocks. Mercury-vapour lighting is installed in all the shops, which are centrally heated. A feature of the heating system is that there are no ducts whatever under the floor of the shop, the whole of the mains being carried close to the roof. In addition the radiators, which are at floor level, are mounted between the stanchions, thus keeping all floor and wall space entirely clear. The flow and return up to the mains overhead is effected by pumps in the circuit. The roof loops work by gravity, which ensures that when the shops are not working, and the pumps are out of action, the system maintains the shops at a minimum temperature. The boiler house is equipped with a battery of four boilers, each capable of an output of 1,227,000 B.Th.U. per hour, and fitted with automatic underfeed stokers.
Situated almost in the centre of the shops is the stores, which are thus equally accessible from every part of the machine and fitting bays. An inspection department adjoins the stores, and all material and machined parts enters the stores through this department. Approximately half the floor space available for production is devoted to machine shops, the remainder being used for assembly and final manufacturing processes. The equipment of the heavy machine shops includes the latest types of high-speed planers, boring, and milling machines, also hydro-electric surface grinders, on which all tables are precision-ground instead of being scraped by hand. The layout of the shops is arranged to facilitate an orderly progression of work through various stages of manufacture, and extensive use is made of special jigs and fixtures. The hardening shop is provided with all the necessary equipment for scientific heat treating. Electrical welding equipment is also available in this shop for general welding purposes, and is also used to a limited extent for fabricated constructional work. The provision made for testing finished machines is one of the features of the works. This takes place in a separate department adjoining the fitting bays.
A dust collecting system, similar to that normally used in a woodworking mill, is installed to enable the high-production types of machines to be operated without interfering with the routine work of the department. As practically all the machines are electrically driven, plant is available on the test bed to enable every machine to be given operating tests on an electric supply identical with that from which it will operate in the user's works.
The application of electric drives to woodworking machinery provides many and varied examples due to the fact that the range of machines is considerably wider than is the case with most other classes of machine tools, and the variation of both feed and cutter-block speeds is considerably greater. Moreover, certain types of machines, such as double-end tenoners, embody as many as twelve separate built-in motors, the control of which is complicated by the need for braking, reversing, "inching", and automatic control to prevent overrunning, in addition to straightforward start and stop controls. High-frequency operation of multi-motor machines is also common on machines such as high-speed moulders, which provides further scope for specialized electrical applications.
There is a pattern shop housed in a separate building adjoining the main shops. Patternmaking machinery is a speciality of the firm, and in the early years of its history, production was devoted almost exclusively to this class of machine. In this connexion, it is interesting to note that the firm originated the pattern miller, or mechanical woodworker. The firm's own pattern shop is particularly well equipped, and shows how patternmaking operations can be appreciably quickened by the intelligent application of machinery.
The business was founded in 1884 by the late Mr. H. H. Wildt, father of the present managing director, Dr. Edwin Wildt, and is one of the oldest companies manufacturing circular knitting machinery. The plant was removed to the present factory in 1928, and in 1935 the acquisition of the knitting machine business of Messrs. William Spiers, Ltd., substantially increased the already extensive range of machines by the addition of models for the automatic production of ribbed footwear, etc.
The present range of manufactures therefore comprises machines for knitted footwear of all kinds, and underwear and outerwear, in both plain and fancy varieties. High-class winding machinery is also a speciality, covering the needs of all branches of the knitwear industry. In addition to the home market there is a substantial export trade.
Adelaide Works is a two-story factory, having a total floor area of 26,000 sq. ft. The ground floor is solely devoted to the machine shop. Among the modern machines with which it is equipped are two of the latest Heidenreich and Harbeck bevel gear shapers. The work done on these machines is mostly the machining of large gear rings having an exceptional pitch-cone length. A range of Webster and Bennett boring mills is engaged on producing the large circular beds and cylinders which form part of the body machines. Of special interest is the cutting of the needle "tricks" in cylinders and dials, and several special machines have been designed for this purpose.
At the rear of the factory are the finishing, hardening, enamelling, and plating shops, the latter having equipment for both nickel and chromium finishes.
The upper story of the factory is divided into two wings, one of which houses the fitting and erecting departments. The work is moved down the shop as it is completed, and then passes into the testing department, situated in the opposite wing. In the latter department the machines are subjected to rigorous testing and final inspection before dispatch.
The main drawing office is situated towards the front of the factory. A projection room is attached for the inspection of needles and small pressed steel components. Along the front of the building are the general offices, foreign department, and the private offices of the managing director and other officials. The total personnel numbers approximately 450.
The business was founded in 1896 by Mr. S. W. Wilkinson, who from the outset specialized in machinery for manufacturing chemists, including machines for making, filling, and sealing medicinal gelatine capsules at one operation. Mills for mixing and grinding the materials for the production of ointment, toilet cream, tooth paste, etc., were also manufactured. Later the firm introduced tablet-compressing machines, in both single-punch and rotary types, for producing medicinal tablets in very large numbers. These machines are now also largely used in the plastic materials industry.
The company originated in 1753, and is entirely self-contained, spinning its own yarn, knitting, dyeing, finishing, making-up, and disposing of the finished products direct to the retailer. The various processes of manufacture are carried out at fourteen factories by 6,000 employees, of whom nearly 4,000 are employed in Leicester. Every variety and size of knitted goods is manufactured: underwear, outerwear, and footwear, including silk hose.
Of the Leicester factories "Bruin Street" furnishes a good example of seamless footwear knitting on a large scale. It has a weekly output of 20,000 dozen pairs of plain and fancy footwear in pure and artificial silk, wool, and cotton. This factory is planned on modern lines on the Bedaux principle, and each battery of machines is separately driven by its own motor unit, the power supply being taken from the Leicester Corporation Electricity Department.
At Abbey Park Factory, where 1,500 operators are employed, the making up of underwear and outerwear is carried out; in addition, the manufacture of bathing costumes and lingerie is of much interest.
The Abbey Meadow Mills factory covers 7 acres and is a shed building, where bleaching, shrinking, and finishing of underwear, and dyeing and finishing of outerwear and yarns take place. This plant is probably the largest of its kind in the hosiery industry in this country. Most of the dyeing machinery with which the dyehouse is equipped is of stainless steel. Steam is generated in Stirling water-tube boilers and Lancashire boilers at 200 lb. per sq. in. pressure, and 100,000 lb. of steam is required per hour, the coal consumption being 300 tons per week. A Ruths steam accumulator is installed for steam balance and storage. Power is produced by means of back-pressure turbines, the back-pressure steam at 10 lb. per sq. in. being utilized for heating the water for dyeing purposes. The works water consumption is 3,000,000 gallons per week, supplied by the Leicester Corporation Waterworks Department. An electrical change-over system is installed to enable the Corporation electric current to be used when the works power plant is not in operation.
The headquarters at King Street accommodate the offices, showrooms, stockrooms, and dispatch departments. Other factories are situated in Leicestershire, Nottinghamshire, Yorkshire, and in Scotland.
The history of Stewarts and Lloyds begins, as far as the main branches of the company are concerned, about the year 1860, when Andrew Stewart began the manufacture of tubes in Glasgow, and the brothers Edward R. Lloyd and Samuel Lloyd set up the Nile Street Tube Works in Birmingham.
In 1890 Andrew and James Stewart amalgamated with the Clydesdale Iron and Steel Company to form A. and J. Stewart and Clydesdale, Ltd. This was the first step towards control of the material required for tube-making. Soon after the firm were pioneering in the use of steel pipes for high-pressure steam both in ships and on land. About the same time they began to manufacture pipes by the hydraulic welding process. In 1903 the two firms amalgamated to form Stewarts and Lloyds, Ltd. Important interests were secured from time to time in coal mines and iron ore properties in England and Scotland, and in 1920, the blast furnaces, steelworks, and ironstone mines of Alfred Hickman, Ltd., and of their subsidiary, Lloyds Ironstone Company, Ltd., and in 1930 the ironstone mines and blast furnaces of the Islip Iron Company, Ltd., were acquired.
Since 1910 there had been a small iron works at Corby, though the developments resulting in the Corby iron and steel works as they are to-day were planned as recently as 1930. But the world depression had set in, and it was therefore not until the end of 1932 that a modified scheme received the necessary financial support, and the £3,000,000 or so required was made available. Piling operations on the base ground of the tube works site commenced in January 1934; the first tube was rolled in November 1934.
The main advantages of the new works are (1) the provision of a supply of good quality tube-making material, under complete control, at a cost competitive with foreign supplies; (2) the close union of blast furnaces, steel plant, and tube mills in an integrated whole, resulting in greater efficiency and economy; (3) increased ability to compete in the world's markets; and (4) a better tactical position in bargaining with makers in other countries through independence of foreign supplies.
The Corby Iron and Steel Works. The ore used in the works is obtained from the ironstone deposits of Northamptonshire, one of the largest in the world, of which the firm owns and controls some 500 million tons. The ore, which lies in flat beds averaging from 8 to 10 feet in thickness under the overburden which varies from a few feet to 50 feet in thickness, is of a phosphoric nature which makes it particularly suitable for the basic Bessemer process and also for the open hearth by means of duplexing.
The iron and steel works comprise an ore-treating plant specially designed to cope with the peculiar physical and chemical qualities of the ores as well as the irregularities typical of these deposits; a modern blast furnace installation of four units, including the largest in Britain and embodying many new features to enable the operation to be conducted by an entirely new method of smelting; a modern coke and by-product plant, designed to produce a quality of coke most suitable for the production of low-silicon pig iron; a basic Bessemer plant of new design, including two large hot-metal mixers, a phosphate slag plant, a lime-burning plant, and four converters; an installation of blast furnace gas-fired soaking pits with metal recuperators; a heavy blooming mill, an intermediate mill, and two semi-finishing 24-inch mills; blast furnace gas-fired reheating furnaces with double metal recuperators; a strip mill of the continuous type for rolling strip for the tube works, and a continuous narrow strip mill, now under construction.
Surplus Gases. The entire operation is carried on without the use of coal or other extraneous fuel, excepting the coking coals charged into the coke ovens. In raising steam, heating of ingots, and reheating billets and slabs, as well as in the steelworks and rolling mill operations, the fuel used is either blast furnace gas or coke oven gas, or a mixture of both. The coke ovens are fired with blast furnace gas, making available the whole of the coke oven gas for other uses within the plant and for supplying the town of Kettering with domestic fuel, through the Kettering Gas Company.
The use of blast furnace gas especially in the coke oven silica regenerators and also in the heating furnace recuperators, made it necessary to clean the gas very thoroughly. Blast furnace gas of high purity is especially economical for use in hot blast stoves, boilers, and soaking pits.
The problem of cleaning the blast furnace gas at Corby is solved by the application, consecutively, in the cleaning system of five processes, each fulfilling a definite purpose. The first two are carried out in the hot dry state and consist of precipitation by slow motion followed by elimination from the gas current through high tangential velocity; the last three are wet stages consisting of static washing, mechanical washing, and electrical precipitation. In the wet cleaning stages the gas is consecutively washed with hot and with cold water, the hot water ensuring the breakdown of the surface tension between dust and water, and the cold washing condensing the water vapour and completing the fine cleaning. The gas is delivered at almost atmospheric temperature with a minimum of absolute moisture and entrained water.
The whole installation is under pressure maintained by the turbo-blowers which furnish blast to the furnaces at a pressure averaging 15 lb. per sq. in. The gas pressure at the top of the furnaces averages about 18 inches water gauge and the clean gas passes into the distributing system at about 8 inches pressure. A 2,000,000 cu. ft. gasholder maintains uniform pressure. The blast furnace gas is distributed throughout the works, the differential pressure between the various mains being maintained by automatic control. A clean-gas bleeder, also automatically controlled, can keep the holder piston at any desired level. This holder, as well as the coke oven gas holder, is of the waterless type.
By-Product Plant. The by-product plant consists of 113 Becker coke ovens, of the cross-over flue regenerative combination type, arranged in three single batteries. The capacity of each oven is approximately 14.5 tons of coal, and the plant was designed for an output of 10,500 tons of coke per week. Either blast furnace gas or coke oven gas can be used for firing, and the gas mains are arranged so that any selected number of ovens can be heated by blast furnace gas, while the remaining ones are heated by coke oven gas. The gases are flushed with liquor and the condensed tar collected. Final tar extraction is carried out by electrical precipitation units in parallel. From a holder of 1,000,000 cu. ft. capacity the gas is distributed to the various plant units. Surplus gas is released through a bleeder automatically controlled.
The by-product plant comprises an ammonia plant and a benzol plant. The first-named is of the indirect recovery type and no liming of the liquor is employed, as the effluent evaporation plant is designed to recover ammonium chloride for use within the works. The benzol plant is designed for recovering a crude spirit, equivalent in quality to a once-run product, a secondary fraction being simultaneously obtained which contains the wash oil and the naphthalene.
The coal-handling, washing, blending, and crushing plant is designed to handle 5,500 tons of raw coal in 45 working hours. The washer box, fitted with a patent stirrer, is of the type in which the coal and the dirt are stratified by vertical pulsating currents of water.
Basic Bessemer Steel Plant. This is the only basic Bessemer steel plant in the country. Each of the four converters has a capacity of 25 tons, with a maximum of 28 tons, and they are supplied with molten pig iron from two 1,000-ton mixers specially designed to conserve heat and to equalize the variations in the hot metal. These mixers are fired by automatically controlled coke oven gas burners, one at each end, with an auxiliary burner at the spout. The metal is brought to the mixer directly from the blast furnaces in 60-ton ladles. The basic Bessemer vessels are blown by two turbo-blowers which maintain the air pressure at any required figure. Blast furnace gas-fired kilns provide the requisite lime.
The soaking pits operate with "straight" blast furnace gas or with mixed gases; the proportion of blast furnace and coke oven gas in the mixture is automatically controlled, and is variable between wide limits. From the soaking pits the ingots are transferred to a 40-inch reversing blooming mill, and after being rolled to specified dimensions in the subsequent mills the blooms, slabs, and billets are cut by hot shears into slabs. Eventually, the billets pass into reheating furnaces or into stock. The reheating furnaces can be fired with a mixture of blast furnace and coke oven gas having a calorific value of up to 180 B.Th.U. per cu. ft., and they are the first to be built in this country with all-metal recuperators.
Finally, there is the strip mill from which the finished coils of steel emerge ready, after cooling and inspection, for transfer to the tube works.
Tube Works. The buildings have a covered area of 14 acres. A broad central roadway divides them into north and south sections. In the former are the tube mills, galvanizing shop, and services. The various finishing shops, tube and fittings warehouses, and packing departments, are grouped in the south section. These discharge the finished and packed products into a transverse loading shed. The central roadway forms the main access to the works.
Two processes have been installed: (1) the Fretz-Moon process, a continuous welding process for tubes from 1/8 inch to 2 inches nominal bore; there are three mills of this type, with an annual output of 160,000 tube-tons; (2) the Wellman push-bench process for seamless tubes, with a range of 2.5 to 4 inches nominal bore, working in conjunction with a reducing mill of a special type for reducing down to 3/4 inch nominal bore; the capacity of this plant is 50,000 tube-tons per year.
(1) Fretz-Moon Process. The essential attraction of the process is that the weld is effected under ideal conditions. The correct temperature, speeds, drafting — in fact, all the conditions necessary to give a high-grade and consistent weld — are possible by this method, since each operation is under scientific control. In addition, all the steel used on the Fretz-Moon mills is manufactured at Corby to the correct analysis and standard of quality. It is interesting to note that in Germany the Fretz-Moon tube has displaced the seamless tube for many purposes. In the north end of the shops lie stocks of coiled strip, transported from the skelp mill on an electric 20-ton bogie, from which overhead cranes lift the coils in batches into stock, and thence to the furnaces. The coils are first weighed, and placed on an unreeling drum; they pass thence to a power-driven levelling machine which flattens the strip, then through shears which trim the ends of the coils square, to a flash-welding unit, where the end of one coil is welded to the start of the next coil. Thence they travel to the furnace via a long inclined slope, on which the strip forms a loop. The purpose of the loop is to allow the mill to continue to draw strip through the furnace whilst the flash welding operation is taking place. During its passage through the furnace the strip is supported on water-cooled rollers and skids, clear of the furnace bottom. On emerging from the furnace at a temperature of 2,550 deg F. the surfaces of the strip are cleaned by means of lateral and vertical air blasts before they enter the first pair of rolls in the welding train. These form the flat strip into circular section with a slight gap between the edges. The edges are again subjected to an air jet, and pass immediately to the second pair of rolls which exert considerable pressure on the formed strip and press the edges together, effectually welding the edge surfaces. Four more sets of rolls serve the dual purpose of consolidating the weld, and drawing the strip through the train. The velocity of the strip varies, with the size, from 2 to 4 ft. per sec.
The red-hot tube leaves the rolls in a continuous stretch, and is cut to length by a flying saw, synchronized with the mill drive through an intermittent reciprocating gear. The actual lengths cut can be varied whilst the mill is running. The cut lengths of tube travel on a live roller trough to the first cooling rack, through the descaling rolls, over two more cooling racks, and through a cooling spray, to the "frazing" machines, which remove the "rag" left by the hot saw. The tubes are then subjected to the first cold examination and passed to collectors on a 5-ton weighing machine. From this point, the 5-ton "hoists" either go direct to the finishing shops, or to the galvanizing shop stock, as plain-end tubes.
(2) Wellman Push-Bench Seamless Process. The raw material for this plant consists of square steel billets, of 6 x 6 inches to 8 x 8 inches section and from 2 to 3 feet in length, according to the size and gauge of tube required. After heating, the billet is pierced with a blind hole, into which is inserted a long mandrel bar. The bar, with the hot billet on its forward end, is pushed through a series of steel dies of decreasing diameter, the effect of which is to draw or elongate the billet backwards along the bar during its passage through the dies. The difference in diameter between the bar and the last die determines the gauge of the tube. The bar is then withdrawn; the solid nose end and the back end of the tube are cut off, and sizing and straightening operations follow as usual. The raw material takes the form either of cold-sawn or cold-broken billets. The latter are produced from long billets by means of a special billet-breaking machine. The sawn or broken billets are fed into a large circular furnace with a rotating hearth which carries the billets slowly round from the entering door to the point of withdrawal. This takes from 1 to 1.5 hours, depending on size. The furnace is heated by a mixture of coke-oven and blast-furnace gas-fed high-pressure burners. The hot billet is withdrawn from the furnace and quickly transferred to a powerful horizontal piercing press, actuated by a water pressure of 2,500 lb. per sq. in. The pierced billet, or "bottle" as it is now termed, is then placed in the "ring bed," a long slotted bench holding the train of circular die rings. This bench is a continuation of a still longer rack bench which carries the cross head and "pusher bar". It is the latter which pushes the mandrel bar into the billet, and both through the dies.
As soon as the bar, carrying the newly formed tube, is free of the last ring, it travels on a live roller track to the polishing mill. An endless-chain bench then withdraws the mandrel bar, which travels back through an ingenious set of live roller tracks and an automatic reversing bridge to a reheating furnace. The tube, now released from the bar, is rapidly carried to hot saws of the pendulum type which remove front and back ends, and on to a powerful sizing mill which "rounds up" the tube and "sizes" it to an accurate outside diameter. Thence the tube is passed over long cooling racks, where cold examination takes place, to the cold-straightening machine, and on to cutting-off machines which remove the saw fraze. Here, the tube is again examined and gauged, before passing to plain-end buffer stock, galvanizing, or finishing shops. The plant is laid out for the production of seamless tubes up to 30-40 foot lengths.
The push-bench at Corby represents a new development of the process. The plant is designed on mass-production lines and, when finished, will produce up to 18 tons per hour. To obtain this rate of output the push bench will operate on only two standard diameters of tube, all other diameters being obtained by passing the tube through the reheating furnace and reducing it in the auxiliary mill to the required diameter. The reheating furnace also ensures that all tubes irrespective of size, are finished at the correct temperature for any subsequent manipulation.
Galvanizing Shop. The "hot-dip" process is employed, and two large galvanizing baths are in operation. The "black" tubes are first pickled thoroughly to clean the surfaces. Special pickling equipment ensures that the tubes are constantly moved whilst in the acid tanks, and that the acid circulates freely over both external and internal surfaces. After pickling, the tubes are washed, drained, and fluxed all over in a special bath maintained at a temperature of 160 deg. F (70 deg. C.). The tubes are then allowed to drain; when dry, they are fed into molten zinc baths in which they remain until the zinc has thoroughly coated the surfaces. On withdrawal from the bath by means of a magnetic roller train, the excess of zinc from the outside surface is removed by passing the tube through a circular jet of air, which has also the effect of "sealing" the hot zinc surface.
The inside of the tube is cleaned from stray flux or beads of zinc by means of a jet of superheated steam, after which the tube is quenched in water and passes on roller conveyers to collectors under an overhead crane. The waste pickle liquor is treated in an acid recovery plant, and after having been brought up to strength again, is circulated back to the acid tanks. The ferrous sulphate which is contained in the waste liquor is removed by a process of refrigeration, and appears as a by-product in the form of "copperas " (iron sulphate).
Warehouses and Pickling. From the four finishing shops, the tubes pass to the warehouse sections, the size of which indicates the large stocks held. The total warehouse capacity is about 10,000 tons. The main stocks are in the 2-inch range and under, arranged by qualities (e.g. gas, water, and steam; galvanized and ungalvanized); separate sections are allocated to short lengths, plain-end tubes, and special gauges.
Bogie trucks are used for bringing tubes as required from the various bays to the packing trestles, on which the tubes are bundled, wired, labelled, and marked. From the trestles, the tubes are carried by gravity to the loading shed, where two lines of sidings are served by three 5-ton overhead cranes and a 3-ton petrol electric mobile crane. The fittings warehouse, containing more than 3,000 separate bins, also opens into the loading shed. When working to full capacity, about 200 main line railway wagons leave the shed daily.
Gauge Room. In a small building allocated to the inspection staff are kept the various sets of reference gauges against which the working gauges used at the tube mills and in the finishing shops are checked at frequent intervals. The reference gauges are themselves checked periodically by exceedingly accurate measurements taken in specially designed machines in a central gauge room. Routine examination is also made of all screwing tools before they are issued to the shops, and for this purpose an optical projection machine is employed. This instrument throws a highly magnified shadow of the tool on to an opaque screen, and comparison can thus be rapidly made with a standard profile permanently drawn on the screen.
The works were originally laid out for the manufacture of 60,000 tons of Portland cement per annum, but have been extended to produce 170,000 tons per annum. The whole of the plant is of modern design.
The cement is manufactured from clay and limestone available on the company's property. No explosives are required in getting the limestone, which makes the working very economical. The siliceous and aluminous clays and the limestone are of the highest grade and the slurry mixing operation is carried out by the usual mechanical mixer, but in addition the slurry is aerated at intervals by means of a compressed air installation, thus ensuring very thorough mixing.
Ketton freestone, which is regarded as one of the best weathering stones in the country, is also obtained from the quarries.
The history of the firm shows it to be one of the pioneers of the electrical industry. The company was founded in 1879 at Lambeth under the name of the Brush Electric Light Corporation, and was closely associated with the early practical application of electricity to lighting. The manufactures in those days included the building of the early dynamos, and the "Brush" arc lamp invented by Charles Francis Brush, of Cleveland, U.S.A., an inventor whose name, like Edison, will always be associated with the early years of the electrical industry. The "Brush" arc light used for the illuminating of piers and promenades years ago was the forerunner of the wonderful illuminations which seaside resorts have developed so extensively. The company gradually grew in importance, and in 1889 the business was transferred from Lambeth to the present works in order to develop the manufacture of complete generating plant on a large scale. It was in this year also that the company's name was changed and registered in its present form.
The Falcon Works cover an area of 35 acres and give employment to approximately 1,600 workers. The present products include turbo-alternators with outputs up to 60,000 kW.; Diesel engines with outputs from 60 b.h.p. to 1,000 b.h.p.; alternating- and direct-current motors and generators; rotary and motor converters; complete Diesel-electric plants; switchboards and switchgear; homogenizers; power and distribution transformers; and road transport passenger vehicles. The works are laid out in three sections as follows, each self-contained and possessing its own staff of specialists: (1) the engineering section, which deals with all but the last two of the items named in the preceding paragraph; (2) the transformer section; and (3) the rolling stock section.
(1) The Engineering Section. This consists of a group of well-arranged machine and erecting shops with a foundry and plant for the manufacture of light and heavy engineering products. The turbine shop is the outstanding building in this section and was designed and built especially for the efficient production of turbines, alternators, and condensers. The building covers an area of more than 1 acre and is so constructed that the roof weight, crane gantries, cranes, and hooks are carried on an independent steel structure supported by well-proportioned brick walls.
For handling the heavy machine components, main cranes up to 50 tons capacity are provided on gantries at various heights from floor level. Each has a span of 75 feet and can travel the whole length of the building. There is also a 6-ton Goliath crane running transversely at the south end of the shop.
The machines in the shop are so arranged that all heavy components of the turbo-alternator sets may progress through the shop from the rough casting or forging stage and reach the further end as completed components ready for assembly. Of special interest is a horizontal boring, milling, and facing machine which was specially designed for the machining of large turbine casings and condensers. One end of the shop is devoted at the present time to the erection of turbines and Diesel engines, and the testing of the latter.
In the past few years, the company has developed turbines of the Ljungstrom type up to the largest sizes, owing to the falling off in demand for the smaller sizes. An outstanding example is the 37,500 kW. continuous maximum rating set recently installed at the Southwick power station of the Brighton Corporation electricity undertaking. This set is the first of two on order; the second set was in an advanced and interesting state of construction during the visit. Designs and constructional details for units up to 60,000 kW. have now been completed.
The turbine is of the double-rotation radial flow type in which steam flows radially through concentric rings of reaction blading, which are secured alternately to the faces of a pair of oppositely rotating disks. Each disk is overhung from the inner bearing of one of the two half-capacity alternators which are driven by the turbine. The rings of one disk are interleaved with those on the other so that the relative speed of adjacent rings is equal to twice the actual running speed of the machine. An important feature of the set is the small space occupied by the turbine blading as compared with the actual size of the complete machine. Unlike the axial flow turbine, the Ljungstrom type has no long shafts and no heavy rotating parts to absorb heat. For this reason the plant can be started without any preliminary warming and can be put on load extremely quickly.
The firm's Diesel engine previously mentioned is of the horizontal opposed cylinder four-stroke compression-ignition type. The engine is totally enclosed, is fitted with forced lubrication, and operates on a very wide range of fuel oils. Built with from two to eight cylinders, units are available for outputs from 60 to 1,000 b.h.p., and complete Diesel-electric plants with electrical outputs to correspond are also manufactured.
In other workshops connected with the engineering section, alternating- and direct-current motors and generators, several interesting rotary converters, motor converters, switchboards and switchgear, motor-generator sets for the Admiralty, planer and welding equipments, and other electrical equipment, are to be seen in course of construction. The process of homogenization is rapidly finding place not only in the production of dairy creams, ice cream, cheeses, foodstuffs, pastes, sauces, salad creams, etc., and in the preparation of pharmaceutical and chemical products, but is also being applied in many ordinary industrial fields where a stable suspension or emulsion of oils and the like in water or other liquids is required. The firm has developed its own type of homogenizer. The machine consists essentially of an electrically driven three-throw pump of solid construction and a patented homogenizing valve of stainless steel through which the product passes under high pressure.
(2) The Transformer Section. The building up of power and distribution transformers requires precision. This section occupies a modern and specially equipped building. The work includes the assembly of the laminated iron core, coil-winding and impregnation, the assembly of the transformer and the switch fittings, such as tap changing, etc., the tank fitting, and the exacting final test. The manufacture of transformers from kVA. up to the largest sizes has been carried out by the company for over 50 years, and transformers built 30 and 40 years ago are still in service.
(3) The Rolling Stock Section. This section consists of extensive workshops to handle every detail of the building of modern road passenger transport vehicles. In the past, before the larger railways had set up their own organizations for building rolling stock, the company built railway rolling stock for home and abroad. Later came tramcars; the first steam trams were followed by electric trams, and to-day's demands are for complete bodies for single- and double-deck buses, long-distance coaches, and trolley-buses. The vehicle bodies are of composite and patented all-metal construction. The company produces large numbers of road passenger vehicles for use by corporations and transport companies in all parts of the British Isles.
Established after the War, the growth and progress of the college have been phenomenal. In its primary function of training young men for the profession of engineering the college initiated a new system which has met with remarkable success. Centred in the Midlands, the college has attracted recruits from all parts of the world and is now recognized as a centre of international repute.
The main buildings are situated in the heart of the town, but the residential halls and athletic facilities are on the edge of the Charnwood area. The courses of training in the engineering faculties embrace practically all branches of the profession, except marine engineering. The workshops accommodate over 300 modern types of machine tools and, on the academic side, the college possesses aerodynamic, heat engine, and high-tension laboratories of some importance. Loughborough's system of training on production methods meets in a very definite manner many of the requirements of modern industry.
The college maintains its own generating station. The plant includes one 1,850 b.h.p., one 550 b.h.p., and one 330 b.h.p. Diesel engine, in addition to other complementary plant. The station is operated in accordance with the practice usual in modern generating stations. The equipment includes Brush transformers and converters, a Cochran waste-heat calorifier, an Imperial Chemical Industries degreasing plant, and Morris overhead travelling cranes.
In 1929 a textile testing house was opened with the dual purpose of providing instruction to students and giving commercial service to the hosiery manufacturers and dyers of the district. The textile testing house and the dyeing laboratory adjoining are fully equipped with the requisite plant.
In addition to the Faculties of Engineering and Pure and Applied Science, the college trains men for the teaching profession; and the workshops and equipment for this branch are comparable with those on the engineering side. A Junior College for Boys is also included in the scope of college activities.
Possessing nearly 80 acres of playing fields, the college last year established a school of athletics, games, and physical education. The amenities for athletics include modern gymnasia and a fully equipped open-air swimming pool. An indoor swimming pool is under construction. A magnificent stadium - the first of its kind in England - is to be opened this summer.
The welfare of the students is catered for in comfortable halls of residence, modern in design, up to date in equipment, and providing single bed-sitting rooms for those in residence.
From small beginnings in 1919, the college has now grown to register nearly 800 full-time day students and, if other types of students are included, the enrolment figure for the current year totals 3,495. In addition to the general educational work, a Summer Vacation School is held annually and last year over 700 individuals attended for periods ranging from one to four weeks.
The firm was founded originally in London in 1884, but was moved to Loughborough in 1904. The first site was soon covered, and adjacent areas were bought up and buildings erected, until there was no room for further extensions. Then in 1922 a site of 74 acres was secured at the other end of the town, alongside the main line of the London, Midland and Scottish Railway. Careful plans for an efficient layout were prepared and by 1924 a large and convenient works was in occupation. This has since been twice extended, and the total floor space now exceeds 22 acres.
There are thus five works, known respectively as the North, South, East, West, and the Boiler Works, constituting what is probably the largest plant in the world devoted exclusively to lifting, travelling, and conveying machinery.
The arrangement of the works is mainly functional, operations of a similar type being grouped together for the sake of manufacturing efficiency. This principle is, however, not adhered to pedantically, as experience has shown that the machining of certain components, particularly those of a heavy type, or those required in very small numbers, can be best performed in the vicinity of the appropriate assembly bay. The same principle applies to the stores for finished articles, which are placed conveniently close to the respective assembly areas.
In general, the South Works is devoted mainly to the production of quantities of small machined parts. Automatic machines, multiple-spindle drills, grinders, gear cutters, and a variety of special-purpose tools are grouped according to type, and the resulting output passes successively into the inspection department and to the "finished stores".
Of exceptional interest is the section devoted to the making of electrically welded chain. As the chain is required to have a very high tensile strength, coupled with great accuracy of link form and pitch, the methods of making it display an unusual combination of skilled craftsmanship with highly automatic machines for the processes which demand exactitude rather than judgement.
The East Works contain the foundry, a small forge shop, and an extensive electrical section for the winding of coils, brake magnets, resisters, controllers, and special switchgear.
At the North Works are the heavier manufactures, including the structural steelwork plant. Here the large electric overhead cranes are built, together with Goliath cranes, steam jib-cranes, electric jib-cranes, and a wide variety of conveyers and elevators.
An especially interesting section of the North Works is the testing bay where electric cranes are lifted on to variable-span gantries and tested with the exact equivalent of the customer's current supply. The means for securing this range of alternating and direct current supplies and the accompanying switchboard are probably unique in the crane trade. These works have recently been extended by 2.5 acres, and production is now commencing in the new extension.
Another outstanding feature is a Goliath crane in the yard, which is designed to handle the assembly of cranes too lofty for the inside of the works. This crane is of 25 tons capacity with a clear lift and span of 100 feet. The design contains many interesting details.
A growing amount of electric welding is now undertaken, and the operations involved, as well as the effect on design, are of particular interest at the present time. The efficient handling of the materials of manufacture has received attention, and has been attained mainly by a highly efficient layout of the works as a whole.
The firm manufactures pure silk hosiery, wool hosiery, fancy half-hose, also underwear and outerwear. Founded in 1805 and one of the first joint stock companies in England, the company has premises which cover 4 acres.
The yarn on entering the factory is subjected to rigid tests for regularity, twist, and condition. It arrives from the spinners on "cops" or cones and is rewound on to bobbins of varying shapes and sizes to suit the type of machine for which it is required. All varieties of yarns are used, including pure silk, wool, cotton, and artificial silk, which after rewinding enter the knitting rooms where they are knitted into ladies' stockings, men's half-hose, ladies' and men's underwear, bathing costumes, children's socks, and three-quarter hose. Of special interest is the ingenuity with which mechanical control is exercised even over a single thread.
The new factory for the manufacture of full-fashioned pure silk hose is of interest from the point of view of its construction. It has a 90-foot roof span without any supporting columns. The heating system, which maintains a constant temperature of 75 deg. F. night and day, and the lighting, which is brilliant but as far as possible shadowless, are also of technical interest. In this section of the premises is installed the latest machinery for the production of 51-gauge and 45-gauge pure silk hose; the former require 34 needles per inch, and leg and foot are made on one machine.
Machine-made bobbin lace was first manufactured by Mr. John Heathcote about 1808, and the first machine made for the purpose was of a semicircular type, somewhat similar to those now used by the Shepshed Lace Manufacturing Company. This machine was constructed at Hathern, a village about 3 miles from Loughborough.
Later on Mr. Heathcote constructed the first plain-net machine (a long straight machine), in Factory Street, Loughborough. His machine was patented and he had much litigation with Nottingham people, who attempted to copy his machine. Later, the Luddites (frame breakers), a party of men who thought that machinery would take away the workpeople's livelihood, visited the factory one night and killed the foreman and several workmen who attempted to protect the machines.
The Shepshed Lace Manufacturing Company, Ltd., was established in 1906 by Mr. George William Price, of Nottingham. There are about 1,200 machines of the circular type in the works at Loughborough. A variety of laces is made and delivered direct to many foreign countries.
The Taylor bell foundry at Loughborough has a history of many centuries and probably had its origin in Leicester between the years 1350 and 1375. From the relatively simple casting of bells in the early days, the skill of the founder has grown, by generations of accumulated experience, to meet the intricate and scientific task of making tuned carillons.
Of the single bells produced by the Taylor foundry, probably the most famous is "Great Paul", the largest in the Empire, used for great occasions in St. Paul's Cathedral. Others include "Great Peter" of York Minster, "Great George" of Bristol University, and "Hosanna" of Buckfast Abbey. The list of ringing peals and tower chimes built in Loughborough is long and honourable. The peals of many cathedrals, parish churches, and universities in this country and abroad have been founded or restored at Loughborough.
But it is the Taylor carillon which has perhaps done most to create the world-wide fame of the foundry, although this is its latest product. Loughborough, naturally enough, is the home of a 47-bell carillon, which is housed in the unique War Memorial tower in Queen's Park, where regular recitals are given. Rotterdam has a Taylor carillon with 49 bells, two more than Loughborough, and the City Hall of Albany, New York, has 47 bells. The beautiful Sanctuary Tower of Mountain Lake, Florida, has a carillon of 71 notes, the largest bell weighing no less than 23,246 lb.
The firm was founded over thirty years ago by the present governing director, Mr. W. F. Charles, with the object of manufacturing flower perfumes resembling as closely as possible the scent produced by natural flowers. In the process of manufacture, natural essential oils, extracted from flowers by means of fat, are used as far as possible. This process of extraction, termed "en fleurage", is one of the oldest known, and is confined almost entirely to the south of France. Special machinery is required for reclaiming these essential oils from the fats, and special attention must be given to the methods of filtration and storage adopted. In the filling and finishing department, either vacuum or gravity fillers are used, and some of the bottles are labelled by machinery.
The powder and cosmetic department is equipped with a vacuum-operated machine for filling the powders into the various tins and bottles. In this room there is also special machinery for sifting, mixing, and perfuming air-blown face and talcum powders.
The factory also contains a large box-making department in which all the display material and boxes used in connexion with the sale of the perfumes are designed and made.
Ball and roller bearings have been made for over 30 years on this site, but whereas initially only a small shop was devoted to the manufacture of these units, the site now occupied extends over 20 acres. The works are divided into the following departments: raw material department; laboratory; ball and roller department; cage department; turning department; hardening department; grindery; fitting-up department; assembly department; and inspection department.
In the raw material department, material is received and classified, and by a system of colour markings, is grouped so as to denote the specification of the steel and the supplier. The laboratory is divided into two compartments. In the first, all material is tested both chemically and physically before being released to the works. The Chief metallurgist is also responsible for the hardening process. In the second, oils, greases, and sundries used for packing purposes, or for the lubrication of the bearing in service, are controlled. This department is also responsible for the correct temperature and humidity throughout the factory.
The ball and roller department occupies a separate building, and is divided into two sections for the production of balls and rollers respectively. In the ball section, cold headers and stamping presses forge balls from steel wire and bar. There are also batteries of grinding machines of special design for grinding the balls after hardening. These can be classified into two groups, the rough-grinding machines, in which the balls are ground between a horizontal steel disk and a horizontal grinding stone, and the fine-grinding machines, where the balls are run between cast iron plates having annular grooves and a grinding wheel held on a horizontal axis.
In the roller section, centreless grinders are employed for grinding the raw material to the correct diameter for use in the small automatic machines. In the latter machines the rollers are turned to length and the radii are formed on the end of each roller. Centreless grinders are also employed for grinding the roller barrels after hardening.
A number of specially constructed grinding machines with special attachments are also in use. In these both ends of the rollers are ground at the same time, whilst the method of holding the work ensures that these ends are square with the axis of the roller. The tumbling barrels in this department are used for obtaining the mirror-like finish on the surface of the balls, whilst lapping machines are employed in the case of the rollers.
Adjacent to this department is the ball and roller inspection department, where all the balls and rollers are subject to individual visual inspection for faults. The balls are graded to 1/50,000 inch, either in a grading machine, or by a comparator, whilst the rollers are measured by a comparative measuring device, both for diameter and length, and are similarly graded. In the cage department, cages are made from brass, duralumin, and bakelite. Multispindle automatic lathes are used for the production of "blanks" from the brass tube, and a number of special drilling machines are used for drilling the ball, roller, and rivet holes. In addition there are other machines for dealing with small quantities of duralumin and bakelite from which cages are made. Pressed cages are also made in this department.
The chief product in the turning department is race rings, as machined before hardening, although other component parts of bearings, such as adapter sleeves, locknuts, and cast iron housings are also machined. The department contains a large number of four-spindle and single-spindle automatic machines, lathes, milling machines, etc.
The hardening department is furnished with a battery of gas-fired furnaces for hardening the rings, and in addition, a number of rotating furnaces employed for the heat treatment of balls and rollers. A special sandblasting plant for the removal of scale from the rings after hardening is also situated here.
Amongst the multitude of grinding machines with which the grinding department is equipped, there are vertical surface grinders with semiautomatic loading devices for the grinding of the fiat sides of the rings, cylindrical grinders and centreless grinders for the outside diameters and bores, also a number of boring machines. In addition, there are special machines with oscillating heads, which are essential to ensure the correct track formation in the rings. The majority of these grinding machines are equipped with electrical and automatic sizing devices.
It is probably well known that race rings after manufacture are "paired up" to ensure that the correct size of inner ring is fitted to the correct size of outer ring, and in the fitting-up department, millions of rings in the hands of expert operators are, after a final test for hardness, assembled with the correct size of ball and roller.
In the final assembly department, rings complete with balls are received from the fitting-up department, and after the correct number of balls is assembled in the bearing, the cage is placed in position around the balls, and the two halves of the cage are where necessary riveted together. A spot-welding process is used in the case of solid cages, and in pressed cages, the riveting is carried out on riveting machines.
Throughout the factory, there are in each department inspection bays where all operations are checked after completion. This ensures the dimensional accuracy of each part before a subsequent operation is performed. Whilst, therefore, every care is exercised to ensure the accuracy of the finished product during manufacture, a further final inspection is imposed in the final inspection department. The bearings are tested for "run", and all external dimensions are again checked. Afterwards the bearings are dipped in special grease vats and packed ready for dispatch.
Among other departments of interest, which are essential to a works of this size, is the tool room, in close co-operation with which is the gauge inspection department, equipped with machines capable of measuring to the finest limits of accuracy, to standards set by Johannsen blocks which are certified by the National Physical Laboratory. There is also a testing laboratory, where bearings are run continuously under varying loading conditions. Here lubricants and methods of mounting and housing are tested, whilst new developments in bearings are tried prior to actual application.
The firm was established in 1790 by James Simpson, as an engineering and shipbuilding company at the Isle of Dogs, London. The founder (sic) was at one time President of the Institution of Civil Engineers, and at a later date was engineering adviser to the British Government. In 1838 the business was transferred to larger premises in Belgrave Road, and thence to Grosvenor Road, London, where a large and complete plant was laid down. At these works the principal pumping machinery for many of the capitals of the world was built.
In 1866 the business was converted into a private limited liability company, and the output so increased that it became necessary to erect extensive new works at Newark in 1900. Since that time further extensions and improvements have been made, with the result that to-day the works cover an area of approximately 15 acres, and give employment at the present time to about 1,200 people.
The general layout of the works provides a typical example of general engineering in all its branches. The offices are situated at the end of the works, and, in addition to administrative sections, include a large and well-equipped drawing office. The main shops comprise: pattern shop, iron and brass foundries, smith shop, plate shop for fabricated work, machine shops, erecting shops, fitting and assembling shops, repair and spare parts departments, packers' department, and test house.
The iron foundry is one of the largest in the Midlands devoted to general engineering work and producing high-grade grey iron and alloy castings. It is equipped with a modern sand slinger, moulding machines, rotary furnaces, and drying stoves. A strict control of metal is kept in the laboratory with both iron and brass foundries, and research work is carried out to determine the best mixtures for castings for special requirements.
The machine shops contain some fine modern examples of large and small machine tools of every type. The larger machines are unit driven, handling work up to 30 tons in weight and 24 feet in diameter. There are two large well-equipped pump test houses, in which transformers and converters are installed so that any desired voltage is available. Pumps of up to 750 h.p. are put through exacting tests, the discharge being measured over calibrated rectangular weirs and Venturi meters. In addition, testing facilities are available for the oil industry, where units up to 500 h.p. are tested with oil under working conditions.
The company manufactures a large and varied group of products, including a complete range of centrifugal pumps, steam pumps and power pumps, also pumping engines, condensing plants and auxiliaries, cooling towers, feed water heaters, evaporators, vacuum pumps, heat exchangers, air compressors, and bottle-washing machinery. Upwards of 500 complete units are dispatched per month, and records show them to be destined for thirty-nine different countries throughout the world, and serving ninety-five classified trades.
In addition to the extremely wide range of standard products, the company specializes in the design and manufacture of large and unusual equipments for docks and harbours, waterworks, sewage, drainage, oil, and petroleum industries, as well as other public utility services; also for the specialized requirements of the main power generating stations, including the whole equipment below the turbine floor, such as main condensers, feed-heating equipment, and pumping machinery. At the present time the company has under erection, on test, and in hand in the shops, machinery of upwards of 750,000 b.h.p.
The site was chosen because it combined road, rail, and water facilities with space for future expansion. It is reached by a new bridge over the London, Midland and Scottish railway. Electricity is generated in the company's power station behind the soap works. It is contemplated that the building will eventually be extended to about three times its present size. At present it provides accommodation for the making, packing, warehousing, and dispatch of all the company's medicinal, toilet, and perfumery products, which are issued in liquid or paste form.
The present structure is sufficiently large to suffice for the next five years. The one-way road which runs round it to the garage is set back to allow for increases in the length of the building, and it is estimated that there is space within its boundary for twenty years' expansion. When the building is extended, the present cross-section will be maintained so that each new department added will have storage, manufacturing, and packing accommodation in the correct proportions. The entrance hall contains a scale model of the works site.
In essence, the works consists of two great halls, the one devoted to manufacturing, the other to packing, linked up with four multi-story buildings, the whole being enclosed by a glass frame. Full use has been made of gravity and automatic conveyers. Raw materials are delivered by rail or motor lorry at one side of the works and are stored in the first two-storied section. When withdrawn from stock, they pass into the manufacturing hall, from which they are transferred, after processing, to the bulk stock department in the basement of the second storage building. The ground floor of this building carries the filling machinery, the upper stories being devoted to the storage of packing materials and to bottle washing.
When filled into appropriate containers, the products pass into the second open hall - the finishing section or packing hall - for labelling, packing into cartons, and boxing, from which they are lifted by elevators and stacked at predetermined points on an upper floor of the third store building. This section of the factory holds the finished stock until it is required for issue to the shops. The finished stock building is also used for assembling the goods for dispatch by rail or lorry to the branches.
The main staircase leads on the right to the packing materials stock, through which the arrival dock is reached. The dock is covered by a remarkable glass cantilever overhung roof which carries two 3-ton travelling cranes.
Manufacturing Hall. Among the sections housed in this hall are the perfumery, pastes, main liquids, tinctures and extracts, and malt sections. The perfumery section is entirely enclosed by glass walls and a glass roof to prevent contamination of the rest of the works by strongly smelling materials. Besides the usual perfumes, alcoholic toilet liquids, such as bay rum and skin tonic are prepared and packed here. In the basement are storage tanks in which the liquids stand until their constituents are blended.
The pastes section deals with every preparation of a pasty constituency, irrespective of its use, and is equipped with batteries of steam-jacketed emulsifiers, mixers, and kneaders. The preparations are conveyed to the appropriate filling machines, at which point they encounter the containers, labels, and cartons descending from the stock departments, after which they pass on to the appropriate packing section in the main packing hall. Similar methods of filling, conveying, and packing are used for the other sections.
In the main liquids department pharmaceutical and toilet emulsions, disinfectants, olive oil, etc., are prepared. The stainless steel pans used for mixing many of these liquids have capacities of 1,000 gallons each and are among the largest in the country. The tinctures and extracts department draws alcohol from a series of copper tanks which form the spirit store on the first floor, the liquid being moved by vacuum and compressed air.
From the manufacturing hall the liquid preparations are conveyed to the bulk stock storage vats in the basement by pipe lines. Tinctures and many specialities are stored in stainless steel; stoneware, mild steel, and pure aluminium are also used for pipes, tanks, and valves. Perfumery products containing essential oils which must be kept from contact with metals are stored in vats of chemical stoneware, protected inside and outside by a special white glaze.
Packing Hall. Packing materials are stored on three floors, the uppermost of which carries cartons, labels, handbills, and the corrugated card and boxes. The lower floors are reserved for bottles, jars, and tubes, and for metal and bakelite caps; the bottle-washing machines are also on this floor. Bottles and jars are supported on pegs and pass, upside down, into these machines; after being washed and dried they remain inverted till they reach the filling tables, so that they cannot collect dust. A system of light signals and telephones informs the stockrooms of the requirements at the packing tables. Cartons and boxes are sent down metal chutes, whilst collapsible tubes are passed down small elevators, worked by gravity and braked by air fans.
Before packing can start, an overlooker presses switches which sound a buzzer in the reserve stock department upstairs and light two electric bulbs - a green bulb at the top of the "paternoster" conveyer, at the point where it discharges into the reserve stock, and a red bulb at the bottom point where the "paternoster" receives the goods from the belt conveyer on the packing table. The buzzer attracts the attention of a member of the reserve stock staff. She switches it off, but leaves the light on until arrangements have been made for receiving the goods. When these are completed, she presses a switch which extinguishes both the green and the red lights. The packing overlooker now knows that there is a free passage for the goods from her table to the appointed place in the stockroom, and can start work.
From the packing hall the boxed goods travel up the "paternoster" to a system of belt conveyers which delivers them for stacking at any required point on the reserve stock floor. Six weeks' to two months' stock is carried. When required, the parcels are sent down metal chutes to the working stock department below, where the shop orders are made up. The working stock department contains an ingenious system of conveyers consisting of a series of trays travelling on an endless overhead rail, each tray being fitted with a mechanically operated release which can be adjusted so that the contents of the tray are tipped on to any desired chute delivering to a packer.
Every item is checked before goods are packed into cases. The cases pass along a slat conveyer to a weighing machine on the dispatch dock. The weight of each case is spoken into a microphone by which it is announced to the control office and recorded.
Analytical Department. The firm established its own analytical department as far back as 1895; this was one of the first analytical laboratories in the pharmaceutical industry. In the Beeston works this department fills the whole of the front of the building at second-story height. There are six main divisions: general drug control; raw vegetable drugs; finished pharmaceutical investigations; toilet preparations; research and fine chemicals; and general investigations. There are also two additional departments devoted respectively to special investigations in chemical engineering, and to research on containers; the latter is probably unique in the pharmaceutical industry. The total number of staff in the analytical department is nearly eighty. Each batch of drugs is analysed at least twice; first as an approved sample, then as a bulk delivery.
Cast iron pipes were first manufactured by the company between 1830 and 1840; the original output was some 400-500 tons per month. This figure rose by the end of the nineteenth century to 12,000 tons per month. The company is now the largest firm manufacturing cast iron pipes in Europe; it has its own coal mines, ironstone and limestone quarries, and is able to exercise direct control over every stage of production. Each week approximately 150 miles of pipes for gas, water, and sewage systems are produced. The company's four coal mines have an annual output of 2.5 million tons; their eleven ironstone quarries an annual output of 1.33 million tons; and their three limestone quarries approximately 280,000 tons. Within the works are about 75 miles of railway, carrying over 70 standard-gauge locomotives and over 6,000 of the company's own railway wagons. A large proportion of the 14,000 employees are housed on the company's property, which includes several thousand acres of land, part of which is farmed.
The chief product is the spun iron pipe, which is made in 3-, 4-, 5-, and 6-yard lengths, and in diameters ranging from 3 inches to 21 inches. Realizing the need for pipe joints which could be deflected under pressure without leakage, two joints - the Stanton-Wilson self-adjusting joint for spun iron pipes, and the Stanton-Cornelius flexible joint for concrete pipes - were introduced by the company. In addition a mechanical lead joint for spun iron pipes is also manufactured.
At Holwell Works, near Melton Mowbray, the company has laid out an up-to-date mechanized foundry. Here standard cast iron "special" pipes are produced in a range wide enough to meet ordinary requirements, together with cast iron drain pipes of all standard types and sizes.
The company also manufactures general castings of all types, and an important recent contract consisted in supplying the 82,000 tons of large cast iron segments used to line the Mersey Tunnel and the 4,600 tons of road setts which form a 3-mile stretch of cast iron highway through that tunnel. A few years ago the firm introduced this "iron road" to provide a permanent surface which would not deteriorate under heavy industrial traffic. The surface is particularly suitable for bus stops, docks, wharves, railway platforms, and loading platforms. For indoor use in garages, factories, dairies, bakeries, etc., a lighter type has been introduced, which provides a permanent acid-resisting surface.
The firm is the largest producer of foundry pig iron in Great Britain and also supplies all qualities of limestone, sand, and many grades of bricks.
Spun Iron Pipes. The Delavaud system of centrifugally casting iron pipes was the invention of a Brazilian engineer, M. Sensaud de Lavaud, who evolved his process after several years of experimental work commenced in 1914.
Realizing the advantages inherent in this method of casting, which dispenses almost entirely with sand or loam moulds and cores, and replaces fallible human skill with mechanically controlled accuracy, the Stanton company first turned their attention to the system when it was still undeveloped. They were the first manufacturers to produce Delavaud pipes on a commercial basis. Recently they carried the development a stage further. By obtaining from Cochranes (Middlesbro') Foundry, Ltd., a licence to use their Mairy (ferro-silicon) process in combination with the Delavaud system, they have now produced a spun pipe with the dense structure, high tensile strength, and perfect concentricity of the original Delavaud pipe, with, in addition, improved ductility, which increases the resistance to shock by at least 50 per cent above that of the thicker vertically cast iron pipe. The plant on which these pipes are cast is the most up-to-date centrifugal plant in Europe. It consists of eight cupolas, twenty spinning machines, and five normalizing furnaces. To supplement the spun plant, the new Nutbrook plant has now been added for producing small-diameter pipes, 4 yards in length. The Nutbrook plant is, however, more fully mechanized, the various handling and conveying operations being carried out automatically. There are eight machines, six of which can be operated simultaneously, and the capacity is 35 miles of pipes per week.
The raw materials and fuel include pig iron, coke, and limestone. These materials are discharged into bunkers, the pig iron being graded according to its silicon content. Samples of all consignments of raw materials are analysed in the company's laboratories. The cupolas, to which the materials are conveyed in skips, are fixed with drop bottoms, and have a melting capacity of 10-15 tons per hour. Here the molten metal attains a temperature of about 1,400 deg. C. when it is tapped into 1.5-ton casting ladles which are conveyed to the spinning machines by means of a 3-ton electric telpher crane. At the head of each machine is a tilting ladle, which is filled with liquid metal. Any scum is removed by a skimmer, the ladle is tilted, and the metal runs down a cantilever trough into a revolving, water-cooled steel mould. Before the metal is introduced, a thin coating of powdered ferro-silicon is distributed over the surface of the mould. This operation enables the pipe to be cast without chill, and produces a valuable metallurgical structure throughout the thickness of the metal. When the socket has been formed, the mould, still revolving, commences a transverse motion, as a result of which the metal is deposited over its inner surface in the form of an even spiral.
As the metal is held against the sides of the mould by centrifugal force, the only core needed is the small one which shapes the interior of the socket. The thickness of the pipe is determined by correlating the rate of tilting the ladle with the longitudinal traverse and the peripheral speed of the mould. The pipe solidifies in a few moments, and is secured at the socket end with a pair of internal pipe grips. "Stripping" is then accomplished by allowing the mould to travel back towards the tilting-ladle. The pipe is then placed on gantries and allowed to roll slowly through a gas-heated normalizing furnace. While still hot, it is coated with Dr. Angus Smith's solution, after which it is tested under hydraulic pressure.
Stanton Concrete Pipes. By means of a centrifugal process, it is possible to produce concrete pipes of considerably greater strength than those manufactured by vibratory or tamping processes. The materials used are best British Portland cement, properly graded Leicestershire granite, and clean-washed sharp sand. All materials, after being sampled and tested, are stored in damp-proof concrete bunkers, and the concrete is subjected to a daily test to ensure the maintenance of high quality.
The wet concrete is introduced into a revolving mould, against the sides of which it is held and compressed by centrifugal force. The temperature of the water used for mixing is not allowed to fall below 60 deg. F., so that the concrete will not be adversely affected during cold weather. During the spinning operation, the hardest and richest concrete automatically collects on the side of the pipes, where the greatest attrition occurs. The centrifugal action also has the effect of expelling the surplus water to the inside of the pipe, thus producing a high-strength non-porous concrete free from voids. After manufacture, the pipes are matured in stockyards, so that their structure will not be adversely affected by changes in atmospheric conditions.
The college was opened in 1881 in the Shakespeare Street buildings now occupied by the Mining and Textile Departments. In 1928 it was transferred to new buildings erected by the late Sir Jesse Boot (afterwards Lord Trent) in a park situated about 3.5 miles from the centre of the city. The college grounds extend to about 100 acres, including the playing fields. There are two halls of residence for men students and a new hall of residence has been opened for women students. The college provides courses suitable for students preparing for the first and higher degrees of the University of London in arts, music, economics, commerce, laws, science, pharmacy, engineering, and mining; and for diplomas awarded by the college in various subjects in addition to engineering, including social study, mining, and fuel technology.
Departments of Civil and Mechanical Engineering. The civil and mechanical engineering laboratories are designed for the study of hydraulics, strength of materials and theory of structures, cement and concrete, metallurgy, and heat engines. There is also a boiler house. The heat engines laboratory was completed in 1930; the others in 1934. The hydraulics laboratory equipment includes high- and low-lift centrifugal pumps, a multistage turbine pump, a three-throw ram pump, a Pelton wheel and a Francis turbine, with the necessary measuring tanks, etc. In the heat engines laboratory, a 60 kVA. turbo-alternator, complete with condenser and pumps, and arranged for experimental purposes, is of special interest. The boiler house contains a Babcock and Wilcox water-tube boiler, with superheater and automatic mechanical stoker, and a Thompson boiler arranged for hand firing. Either induced or forced draught can be used, and an economizer is installed, which can be utilized with either boiler.
The materials and structures laboratory contains a 50-ton testing machine, torsion-impact, fatigue, and hardness testing machines, and other apparatus. There is equipment for cement and concrete testing, and microscopes, electric furnaces, etc., for metallurgy.
Department of Electrical Engineering. New laboratories were opened in 1932 and are divided into five sections: (1) combined elementary and direct-current laboratory; (2) alternating-current laboratory; (3) high-voltage laboratory; (4) standardizing laboratory; and (5) photometrical laboratory. These buildings form, with the power house, workshops, and battery room, a self-contained section of the buildings in the engineering block.
The alternating-current laboratory contains motor-generator sets of various types, different types of alternating-current motors, and a very comprehensive selection of static transformers, both three-phase and single-phase. Two transformers have tappings arranged so that the Scott transformation from three to two phases can be carried out.
In addition to a 440-volt three-wire direct-current supply, and three-phase and single-phase supplies from the power house, three-phase power can also be obtained from the turbo-alternator in the heat engines laboratory. A two-phase low-frequency supply can be derived from the slip rings of a three-wire generator in the power house.
The power house provides the whole of the lighting and power for the college buildings and grounds. The supply is at 11,000 volts, and this is converted into direct current at 440 volts (three-wire system), the chief machine being a 150 kW. rotary converter. This machine has a special armature winding with auxiliary slip rings so that oscillograph records of the flux distribution and the current waveform at a tapping point can be obtained. In addition it is provided with an exciter so that it can be run inverted for experimental work. A 50 kW. mercury-arc rectifier has recently been installed. The standby plant consists of a 440-volt battery, controlled either manually or automatically by a battery booster set, also a cold-starting oil engine driving a three-wire generator with static balancer.
The high-voltage laboratory equipment includes a 25 kVA. single-phase transformer giving 150,000 volts to earth. There are also small transformers giving voltages up to 20,000. For the measurement of high voltage by the sphere gap, the position of the sphere can be read to 0.01 mm. by means of a very accurate cathetometer. The necessary equipment for Schering bridge work is being developed in view of the importance of this method for testing insulating materials.
The standardizing laboratory is equipped with a standard Wheatstone bridge, potentiometers, and Kelvin double bridge for measurement of very low resistance, and also apparatus for iron testing. In addition there is apparatus for the measurement of inductance and capacitance by alternating-current bridge methods.
The photometrical laboratory contains a modern standard photometer bench with heads of different types, and standard lamps for visual photometry. Photometry is also carried out by photo-electric cells both over the visible and invisible ranges of the spectrum.
Since the firm's first factory was commenced in Rugby in 1901 - with about 1,700 employees and 500,000 sq. ft. of floor area - both the works and the company have steadily developed until the present day, when the Rugby works cover 94 acres and give employment to about 9,000 people. The whole British Thomson-Houston organization includes five large works covering about 200 acres and employing over 16,000 people.
There are altogether 81 buildings in the Rugby Works, two of them being 1,000 feet long; and about 6 miles of railway track are laid down for locomotives and mobile cranes, these lines giving direct communication with the London, Midland and Scottish Railway's main line. Inside the various buildings a total of 120 overhead cranes - lifting up to 60 tons - facilitate the handling of heavy parts.
The wide range of products manufactured in these works affords some interesting contrasts in production methods, the lamp factory being equipped with some remarkable machines for automatic operations in the making of lamps in large quantities, while the turbine factory is equipped for the building of very large turbo-generators for steam pressures up to 1,200 lb. per sq. in., temperatures up to 1,000 deg. F., and voltages up to 33,000.
The turbine factory is one of the buildings 1,000 feet long, and is capable of dealing with steam turbines, blowers, compressors, and exhausters of the largest size that the railways and docks of this country are able to handle. Among the special machine tools in this factory are two that rank with the largest in the country; one is a horizontal turbine casing boring machine that will take work up to 18 feet wide and 20 feet long, and will machine work up to a maximum diameter of 18 feet. The other, a planing machine, will take work up to 13.5 feet wide and 12 feet high, the stroke being 25 feet.
Another building 1,000 feet long adjoins the turbine factory and is devoted to the manufacture of large electric motors, generators, transformers, mercury-arc rectifiers, rotary converters, and similar plant. In this shop some very large machines have been built for driving steel rolling mills and for service in other heavy industries. The machine tool equipment of this building includes a boring mill capable of turning work 22.5 feet diameter by 8 feet high, a planer for work 20 feet long by 10 feet wide and 7 feet high, a dividing table for spacing slots accurately to within 0.004 inch, and a 400-ton hydraulic press for consolidating field coils.
Adjoining these two long buildings is the motor factory. This is equipped with modern machine tools, using "Ardaloy" capable of cutting mild steel at 700 ft. per min., for the manufacture of medium-sized machines such as power factor correction motors, alternating-current variable-speed commutator motors, etc. Leading off this motor factory is the measuring room, which is so constructed as to be free from vibration and temperature variation. Some of the machines are capable of measuring to within one-millionth of an inch.
In the press shop about 400 tons of sheet metal are consumed each month by presses ranging from the 2-ton notching presses operating at 720 strokes per minute, to the 500-ton presses for large sheets. The output of this shop is about 40,000 stampings per hour, ranging from 650 lb. to 0.0003 lb. in weight.
All these factories are on the north side of the main avenue through the works. On the south side of this avenue are the foundry, the fabrication factory, the control gear factory, the home appliance factory, the "Mazda" lamp factory, etc.
A feature of the foundry which is probably unique is that it is a three-story building. The ground floor is devoted to machine moulding, and is laid out on the roller conveyer principle for the production of castings for the smaller sizes of motors and domestic appliances. The higher floors are devoted to the production of iron castings up to 10 cwt. and castings in non-ferrous metals, a particularly good example of the latter being the aluminium bowls for washing machines, for which the metal is melted in oil-fired furnaces.
In the fabrication factory are machines that cut, roll, shape, and weld some 4,000 tons of steel structures during the year, although arc welding is also carried out in several of the other factories. The equipment of this department includes oxygen flame cutting machines for steel of any thickness or area, and hydraulic presses capable of exerting pressures up to 400 tons for forming cylinders and rings from cold steel.
One of the largest buildings in the works is the control gear factory, a three-story building devoted to the production of gear ranging from starting switches for fractional horse-power motors up to the most elaborate equipment for controlling motors of 20,000 h.p. and over. This factory is of particular interest, as it provides a fine example of modern practice in individual electric machine tool drive.
Farther down the main avenue is another three-story building devoted to the manufacture of electric domestic appliances, such as refrigerators, cookers, washing machines, etc. In this modern factory the work is handled on the principle of continuous movement.
Although the main lamp factory has been mentioned in the group on the south of the main avenue, it is necessary to add that there is another large building at the western extremity of the works which is an extension of the lamp factory. The plant equipment of the buildings comprising the lamp factory is of special interest, as most of the operations are performed rapidly and automatically, while the dexterity of the operators on certain non-automatic operations is remarkable. The output of lamps from the main factory is measured in millions annually. In the extension building are produced automobile lamps, mercury-vapour lamps, glass-bulb mercury-arc rectifiers, Coolidge tubes, photo-electric cells, etc. Filament-coiling operations also are carried out in this building.
The company's research laboratory occupies several buildings. The main building houses the following sections (1) the electrical and development section dealing with surge phenomena and other high-voltage problems, impulse testing, road-lighting problems, noise analysis, sound measurement, film production, etc.; (2) the vacuum physics section, dealing with lamp research and development, radio valves, photo-electric cells, cathode ray tubes, electron optics, etc.; (3) the high-frequency section, including radio interference problems, all high-frequency measurements, and television circuit development; (4) the insulation section, dealing with synthetic resins and moulding powders, varnishes, compounds, and sheet insulation, and (5) the chemical and metallurgical section, dealing with mechanical, metallurgical, and chemical properties of materials.
Adjoining the main research building is a separate acoustical laboratory and sound film theatre, while near this are the television station, the noise analysis laboratory, and the gas analysis laboratory.
The company was formed in 1918 to consolidate under one management a number of old-established concerns who were pioneers in various branches of the electrical industry. The most important of these were Siemens Brothers' dynamo works, Stafford; the Phoenix Dynamo and Manufacturing Company, Bradford; Messrs. Willans and Robinson, Rugby; and Messrs. Dick, Kerr and Company, Preston.
The sites covered by these four works exceed 150 acres in area; in addition, each works has its own sports grounds equipped for cricket, football, bowls, tennis, etc., so that ample facilities are available for the recreation of the employees.
The company has extended the scope of its activities to cover the whole field of electric power generation and distribution; the rectification or conversion from one form of electricity supply to another; the manufacture of vehicles for every kind of electric transport by rail or road; turbo-electric and oil-electric ship propulsion; and the carrying out of comprehensive contracts for complete power stations and industrial and railway electrification schemes of any magnitude. It also occupies a notable position in Great Britain in connexion with its manufacture of large water-turbine plant. Switchgear and transforming apparatus up to the highest voltages and largest capacities and electrical machinery for every industrial purpose are constructed within the works. Other products include high-rupturing capacity fuses and fusegear, electric equipment, house service meters, and a wide range of domestic electrical appliances.
The particular group of products allocated to each factory is the assult of careful selection in order that the experience, equipment, and local traditions might be used to the fullest advantage of the organization as a whole.
The firm of Willans and Robinson, Ltd., originated in 1880 from a partnership between Mr. P. W. Willans, M.I.Mech.E., and Mr. Mark H. Robinson, M.I.Mech.E., for the manufacture at Thames Ditton, Surrey, of a small high-speed marine steam engine. In 1884 the demand for an engine suitable for the direct driving of dynamos resulted in the development of the single-acting central valve engine which ultimately became famous. In 1888 the concern became a private limited liability company, and in 1893 was reconstituted as a public company. Owing to the need for expansion and better railway facilities, the works were moved to Rugby in 1897. As already stated the business was acquired by the English Electric Company in 1918. To-day the works specialize in the production of prime movers using steam, oil, or water. They stand upon a 41-acre site adjoining the London, Midland and Scottish Railway, the property having a frontage on the railway of over 0.5 mile. About 8 acres are covered.
The main block of buildings comprising the machine and erecting shops is constructed in bays running north and south. At the west end of the main block is the foundry. To the west of the foundry, and completely detached, are the pattern shop and pattern stores. All the shops are well lighted and ventilated and are provided with efficient modern machine tool equipment.
The office buildings in which are accommodated the technical, drawing office, and other staff, are at the eastern end of the works and are approached by a private road. Adjoining the open space in front of these buildings are the power house and a brick-built canteen for the employees, also the works' fire station. At the south side of the works there is a 7-acre athletic ground.
Steam Turbines. The building of steam turbines was commenced as far back as 1903, and during the last thirty-three years a very large number of machines have been built amounting in aggregate capacity to several million horse-power. These machines embraced all types of condensing, non-condensing, back-pressure, mixed-pressure, passout, and extra high-pressure turbines for superposing on existing plant. From the very earliest days it was appreciated by the engineers of the company that high speeds of rotation were desirable in steam turbines, both from the point of view of reliability and efficiency, and more than 50 per cent of the horse-power of machines manufactured by the company represents the output of turbines running at speeds of 3,000 r.p.m. or higher.
The first 3,000 r.p.m. turbine constructed by the company was commenced in 1905, and had an output of 375 kW. This turbine is still in service. From then a rapid advancement in the output of individual machines running at this speed took place - to 1,000 kW. in 1910; to 5,000 kW. in 1914; to 20,000 kW. in 1923; to 30,000 kW. in 1928 (the last-named machine being at that time the largest 3,000 r.p.m. turbine in the country); and at the present time the company have under construction still larger sets for the same running speed, namely, two 40,000 kW. sets for the Yorkshire Electric Power Company. Most of the machines of this type are of impulse-reaction multi-cylinder construction.
Water Turbines. The manufacture of hydro-electric machinery on a large scale was commenced seventeen years ago; the company is the only British manufacturer of large complete water turbine sets (including the associated generators). There is at Rugby a fully equipped industrial hydro-electric test station. It is believed that this is the only plant of its type in the country, as the laboratories at colleges are of course, for educational purposes only. In addition to tests on high-speed runners, etc., the company has also developed the aerofoil flow meter and hydraulic brakes at this test station. While securing many important contracts abroad, the company has been largely instrumental in developing the water power resources of Great Britain, and practically the whole of the water turbine plant in Scotland has been supplied by them. In 1936 they completed the 103,000 kW. hydro-electric scheme of the Galloway Water Power Company.
Diesel Engines. The works have been engaged for more than 30 years in the design and manufacture of four-stroke and two-stroke Diesel engines. A range of medium-speed engines is manufactured in sizes ranging from 150 to 1,000 b.h.p., in addition to their adaptation of the Fullagar mechanical-injection opposed-piston engine with outputs ranging from 980 to 3,500 b.h.p.
The "K" type engines, ranging up to 400 b.h.p. are used extensively for Diesel-electric marine propulsion and for Diesel-electric locomotives. The "L" type engines have outputs from 375 up to 1,000 b.h.p. The 3,500 b.h.p. Fullagar engine built in 1936 for the Bermuda Electric Light, Power and Traction Company is the largest manufactured in Great Britain for industrial purposes.
In addition, the firm manufactures a type of high-speed Diesel engine suitable for railcars, marine propulsion, marine auxiliaries, etc. This engine develops 200 b.h.p. at 1,500 r.p.m.
The company's works, excluding the collieries, cover over 400 acres and comprise blast furnaces, chemical and by-product plants, tarred slag plants, a power station, foundries, wagon shops, and brickyards. The products include coal, pig iron, chemicals, sand-spun, metal-spun and vertically cast pipes, flange pipes, special pipes of all kinds, dry slag, tarred slag, etc., for road making, wood wool for packing purposes, bricks, and sand.
The power used, both in the works and the collieries, is chiefly electrical, although steam and compressed air are also utilized to a large extent. The principal generating station is situated in the works, and has an annual output of over 100 million units. There are three sets of gas-engine driven alternators, each of 5,000 kW. capacity, housed in a separate building. Each gas engine is of the four-cylinder type, arranged twin-tandem with the alternator between the overhung cranks. The cylinders are 4 ft. 3.25 in. bore, and the stroke is 4 ft. 11 in. The three engines require about 300,000 gallons of cooling water per hour, and the temperature of the circulating water is reduced in two large cooling towers. There are also generating stations at two of the collieries, connected with the main station at the works.
All blast furnace gas is cleaned by tower scrubbers and Thyssen washers, and is used to drive the gas engines, any surplus being employed to raise steam. The blast furnaces, coke ovens, chemical, and by-product plants are situated apart from the foundries, and constitute the "Devonshire Works".
The foundries consist of two modern plants for the manufacture of sand-spun and metal-spun pipes, the former being the only one of its kind in the country. There are also general foundries of the usual type. In the vertical-cast foundries, all moulds are hand-rammed.
Though various systems of mechanical ramming have been tried, it has been found that the hand-rammed mould is the most consistently free from hard and soft places, which, of course, produce blemishes on the skin of the pipes. The products of the vertically cast and general foundries comprise vertically cast pipes from 1.5 to 72 inches diameter in 9-foot and 12-foot lengths, flange pipes, hydraulic pipes, and the various classes made to metric and Continental standards when required. Several foundries are laid out for the production of "specials," such as bends, tees, angle branches, etc. Large extensions to these foundries are in hand. Various systems of moulding are adopted, sand slingers, pneumatic jolting, and hydraulic pressing machines being used, also hand and pneumatic rammers.
Sand-Spun Pipes. In the sand-spun pipe foundry, 4-inch to 24-inch pipes are centrifugally cast in sand-lined moulds. These pipes are made in 16-foot lengths. There are seven centrifugal machines, or "spinners", each fitted with a semi-cylindrical safety hood, hydraulically operated. Moulding is effected by jolting machines, into which the flasks are placed three at a time in the smaller sizes, two in the medium sizes, and only one in the larger sizes. Three jolting stations are used together with one pneumatic rammer for the large sizes, the size and weight of the flasks in the latter rendering jolting a difficult operation.
The centrifugal effect in the process prevents the inclusion of non-metallic substances, which are left on the inner surface of the pipe, whence they are easily removed. It is therefore virtually possible to guarantee the pipes free from gas cavities, blowholes, and non-metallic inclusions. The sand-spun pipe derives its superior qualities from the combination of centrifugal action and the use of sand-lined moulds, in which the pipes are allowed to cool slowly, so retaining the ductility of the pit-cast pipe.
Metal-Spun Pipes. In the metal-spun plant, pipes of 3 to 6 inches diameter are cast in water-cooled metal moulds in lengths of 9 and 12 feet for the 3-inch size, and 9, 12, 15, and 18 feet for the 4-, 5-, and 6-inch sizes. Six spinning machines are arranged in line with tilting ladles on an elevated platform. The tilting ladles are supplied by means of "bull" ladles travelling on an overhead telpher system. As the pipes leave the machines they pass along continuously moving conveyers to the main gantry, and thence to the annealing furnace. There is also a smaller shop which contains four spinning machines. All pipes cast in metal moulds are brittle and unfit for service until they have been heat-treated. The special conditions attained in the annealing furnace enable absolute uniformity of temperature to be maintained through the annealing zone, and ensure perfect physical conditions throughout each pipe. Vertically cast, sand-spun, and metal-spun pipes can be made with flexible joints, either of the bolt or the clamp type. This joint is easily and quickly made and permits a variation between adjacent pipes of 8 deg. The only tools required are a spanner for the bolt type, and a hammer for the clamp type. Pipes are also manufactured bitumen-coated and, or alternatively, concrete-lined.
Devonshire Works. The output of coke from the coke ovens is used mainly in the four blast furnaces, which produce annually approximately 250,000 tons of pig iron. The chemicals and by-products manufactured by the firm constitute a long and varied list. The chief items are: tar, pitch, naphthalene in various forms, i.e. pressed, flake, powder, blocks, eggs, etc.; anthracene; tar acids; pyridine; liquid chlorine; caustic soda; hydrochloric acid; benzoic; mirbane oil; aniline oil and salt; nitric acid, sulphuric acid, sulphate of ammonia, and "Stadus" (a floor-sweeping compound).
The works are situated near the village of Swannington, 2 miles north of Coalville. Over a century ago Swannington was the centre of the coal-mining industry in Leicestershire, and, as such, brought about the making of the Swannington Railway, engineered by George Stephenson. The pumping station pumps the water from one of the old shafts, which was sunk in 1853 and is known locally as "Calcutta" pit. The pumps were erected in 1877 by Messrs. Robert Stephenson and Company, Ltd., and they raise about 300,000,000 gallons of water per year. The installation comprises the boilers, the pumping engine, the pumps, and the lifting gear.
The boilers are of the Cornish type, 7 feet in diameter, and 26 feet long; the working pressure is 60 lb. per sq. in. They were made by Messrs. Stephenson. The original boilers are still in use.
The pumping engine was also made by Messrs. Stephenson and consists of a compound condensing horizontal steam engine„ The high-pressure cylinder is 42 inches in diameter and the low pressure cylinder 72 inches in diameter. The stroke is 8 feet; the flywheel is 32 feet in diameter, and weighs 50 tons. The engine is worked at 5 r.p.m.
There are two pumps of the bucket type, pumping from a depth of 90 yards. The diameter of the working barrels is 2 ft. 2 in. A clack piece is fitted at the bottom and a bucket piece at the top of each working barrel. The bucket rods consist of pitch-pine beams 12 inches square, fixed together by double sets of joint plates, and connected to "T-bobs" situated on a bedplate at the surface.
There are two hoists. The heavy one is used for taking out the rods when necessary; it consists of a pair of steam engines having cylinders 10 inches in diameter, a stroke of 2 ft. 7 in. geared 6 to 1; and a rope drum 4 feet in diameter. The light hoist consists of a pair of 8-inch x 12-inch geared winding engines, the drum being 3 feet in diameter, and the ratio of the gears 3.5 to 1. These hoists operate through a steel headgear 70 feet in height.