English Electric Co: Water Turbines

1924. 25,000 HP turbine

Note: This is a sub-section of the English Electric Co

Water turbine manufacture was undertaken at Willans Works Rugby, and at Stafford, until transferred in the 1950s to a new fabrication and heavy machine shop at Netherton, Liverpool. Netherton Works closed c.1970 as part of the rationalisation following the merger with AEI. Some of the staff were transferred to the EE-AEI works at Trafford Park. Some of the machine tools were also transferred, with a view to continuing the manufacture of water turbines and other heavy engineering products at Trafford Park.

1924 Reference to 30,000 h.p. twin-wheel impulse turbines being supplied to the Behira power station of the Tata Company in India, and a 25,0000 h.p. machine for the Sorocaba power station of the Sao Paulo Power Company of Brazil. Parts were exhibited at the 1924 British Empire Exhibition.

1927 GOVERNING OF HYDRO-ELECTRIC PLANT.
'A water turbine is tricky prime mover to govern efficiently. Any means which might cause sudden change in the velocity of flow of water in the pipe-line cannot allowed because of the well-known dangerous increase in pressure brought about the sudden shock of arresting the motion of large body of water. An ingenious type of double-acting governor gear has been used on the six large Pelton or tangent wheel turbines made for the Tata Hydro-Electric Power Company (Ltd.) by the English Electric Company (Ltd.). One of these turbines has gone to the Khopoli Station, and two 30,000 h.p. machines have recently been put into operation at Bhira. The remaining three are now in course of erection at Rugby. It may be remembered that this order was probably the outstanding event of year which saw some remarkable developments all over the world in the use of water power.
The nozzle discharging water on to the peripheral buckets is of the usual Doble needle regulated type. The advance or withdrawal of the needle concentric with the orifice alters the annular opening available, thus controls the diameter the jet. This control must be, as explained above, very gradual. On other hand, governor must able to act almost instantaneously, maintaining close speed regulation even in the event of all the load being thrown off the turbine. To effect this, the needle in the present device, known as the Seewer governor, contains an internal sleeve, which carries a series of guide vanes. When sudden reduction of load occurs, these vanes aro automatically caused to protrude from the end of the spear head, into the line of the jet. Being set at angle, they give the water in the jet a spinning motion, which throws the water into a diffused cone. The small amount of water which now impinges on the buckets has little driving power, and the wheel therefore immediately responds to the reduction of power demand. At the same time the needle itself is being brought slowly forward, to take up its rightful function, throttling the water flow without causing any undue increase in pipe-line pressure. As it assumes its duties, an overtaking gear withdraws the dispersing blades, and restores the solidity of the water jet, albeit with a diminished volume of water.
In tests on 3,300 h.p. turbine, the sudden throwing off of 25 per cent. load resulted in a temporary rise in speed of 1.15 per cent., while the speed increase for throwing the whole load off was only 3.45 per cent. In the Khopoli set, throwing 10,000 k.w. load off suddenly gave a rise of 3.88 per cent, in the speed above no-load speed, while the important increase of pressure in the pipe-line was only 3.59 per cent.'

1934 'A hydro-electric generating set of unusual characteristics has recently been supplied by Messrs. The English Electric Company, Limited, Stafford, to the order of Messrs. Imperial Chemical Industries (Fertiliser and Synthetic Products), Limited, for installation in South Africa, where it is now in successful operation. The somewhat unique features include a water supply of 477 gallons per minute under a head of from 1,700 ft. to 1,870 ft., the water containing in solution from 6 times to 10 times its own volume of gas at n.t.p. The turbine had to be capable of extracting the energy from this supply and of discharging the mixture of gas and fluid to a height of 67 ft. The high head necessitated the adoption of the impulse type of turbine, but this, of course, involved the difficulty that, as the water passes through the nozzle, pressure normally falls at the mouth, so that the gas would be liberated and the water turned into spray, with the result that no useful work could be performed on the wheel. As a result of a theoretical consideration of the case in conjunction with experiments carried out by Messrs. Imperial Chemical Industries at their Billingham works, shapes were developed for the nozzle and buckets which overcame this trouble, the pressure energy in the jet being converted into velocity energy and mechanical power so rapidly that the gas had not time to come out of solution. The first two illustrations annexed [not included here] show how successfully the nozzle problem was solved, Fig. 1 showing a jet of the gas-charged water under the operating head, and Fig. 2 a corresponding jet of pure water for comparative purposes. It will be found difficult to distinguish one from the other, as regards the jets themselves. The requirements with regard to discharging against a head of 67 ft. were met by maintaining the turbine casing under pressure, arranging for the upper part always to be filled with gas, which serves as a cushion to force the discharge to the height required. The wheel runs at 1,000 r.p.m., and is of the overhung type. An alternator with enclosed slip rings was provided to ensure flame-proof conditions and the exciter was driven by Whittle belt. The turbine casing was made of cast steel, in order to withstand the internal pressure, and as this might fluctuate considerably from the nature of the chemical process involved, a test pressure of 70 lb. per square inch was applied to the casing, and an emergency bursting plate is provided in the top ofthe cone, fitted with an exhaust pipe. The runner, shown in Fig. 3, is provided with stamped instead of cast buckets, with the object of ensuring perfectly homogeneous material to withstand the action of the gas-charged water. The bucket splitter edges have been very carefully formed and the buckets have been given a high polish. They are shaped to conform to the results of the special investigations referred to above. They are attached to the wheel disc by a single-bolt fastening, in which a single slightly coned bolt is used in conjunction with a split bush, alternate buckets bearing on shoulders integral with the disc and on driven-in taper keys. Where the shaft passes through the casing it is provided with a stainless-steel sleeve and runs in a watercooled pressure gland. The nozzle and hand-operated spear are also of stainless steel. Axial guide vanes maintain a good jet. No governor is required, as the discharge remains practically constant, but an overspeed trip is provided to guard against emergency. This trip consists of an unbalanced ring on the shaft, held in place by a spring, until the centrifugal force developed by overspeed overcomes the spring and allows the ring to project far enough to engage a trigger. The latter operates a trip valve which brings into operation a deflector directing the jet from the wheel.'

1959 TURBINES AND DIESELS
'TURBINES designed and made at Rugby — or in some cases only designed here — form one of the main sections in the review of the year issued by the English Electric Co. An important part is also occupied by the work done at Whetstone, where thousands of graphite components for the atomic power station at Hinkley Point were made. Among the water turbines made by the company were the first two of four for Table Rock which are believed to be the first water turbines of foreign manufacture supplied to the United States of America. During 1959 the company received orders from the North of Scotland Hydro-Electric Board for two 19,000 vertical alternators for the Deanie power station, and one 22,000 kw vertical variable blade water turbine and associated alternator for the Culligran power station. Both stations are part of the Strathfarrar Scheme in Inverness-shire. In connection with the turbine for Culligran it was agreed with the consultants and the North of Scotland Hydro-Electric Board, that there would he significant advantages in installing a Deriaz mixed-flow variable-blade runner instead of the Kaplan axial-flow runner originally proposed.
This will be the first occasion on which Deriaz runner has been used for a straight turbine without provision for reversible operation.
EVERY EIGHT WEEKS
The manufacturing effort of the past two years on plant for the Priest Rapids power station on the Columbia River in the United State of America resulted in the successful commissioning of the first of the ten 91,000 kw units for this important power station in October, the second unit in November, and the third in December. The turbine runners are the largest of their type on the Columbia River. In spite of the size and complexity of the runners they have been delivered to site with the alternators and magnetic-amplifier voltage regulators to support an erection programme based on one machine being commissioned every eight weeks.
In Australia all four water turbines have been commissioned in the Snowy T.1. power station of the Snowy Mountains Hydro-Electric Authority. These turbines, capable of developing 134,500 h.p. under a maximum net head of 1,095 feet, are amongst the most powerful high-head Francis machines in the world.

PUMPED STORAGE
Other plant commissioned throughout the world included three 36,800 kw hydroelectric sets at Hirfanli in Turkey, which are part of a comprehensive project undertaken by English Electric in conjunction with George Wimpey and Co.; two additional 18,000 kw sets in the Tully Falls Power Station, Australia; 35,000 kw turbine and alternator at Silvon in Spain, and an 11,000 kw water turbine and alternator at Cashlie power station in Scotland. The 50,000 kw hydro-electric set for Warragamba in Australia will shortly be commissioned.
Following the successful commissioning of three 30,000 h.p. turbines at the Atiamuri power station of the New Zealand State Hydro-Electric Department, it was decided to extend the Power station and a further unit has been ordered. Installation has now started on the low-level embedded parts for the four 105,000 h.p. pumps and turbines - Generating Board's Ffestiniog pumped storage station in Wales. This will be the largest pumped storage station in the world when completed.
It was recently reported the company has received instructions from the Central Electricity Generating Board to put in hand two 330 mw turbo-generator units for Drakelow 'C' Power Station. ....'

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