Easton and Amos Beam Engine in Taunton
This engine was built by Easton and Amos and installed in Pearsall’s Silk Mill in Taunton, Somerset, where it worked until 1955. It is now on display in the Taunton Museum (The Museum of Somerset) in Taunton, where it may be seen turning (by an electric motor, on request).
The engine originally drove machinery via a large gear wheel on the crankshaft which engaged with a smaller wooden-cogged pinion. The gear was removed before installation in the museum.
The date of the engine recorded by George Watkins in 1938 was 1850. There is a well-polished plate on the engine which gives a 'started' date, but it is not clear whether this is 1850 or 1856. According to the article below, the date is 1856.
1957 ' Taunton Factory Engine Now in Castle Museum.
The engine has been presented by Messrs. James Pearsall & Co., Ltd., silk throwsters, of Taunton, and installed at the Castle through the good offices of Mr. E. L. Kelting, chairman of the Museum Committee of the Somerset Archaeological Society.
Installed in 1856, it is a compound beam engine made by Easton & Amos and installed Pearsall's East-street factory in 1856. It has a high-pressure cylinder of 12 inches and low-pressure cylinder of 20 inches, and the stroke of the engine is three feet. The fly-wheel weighs nearly four tons and revolves about 26 times a minute. It is geared to a driving-wheel which has teeth of apple wood.
Disappearing Type
Mr. Kelting said this week that the engine is a good example of a type which was quite common a century ago. but which has been scrapped at such an alarming rate, especially during the two wars, that comparatively few have survived. Unless museum authorities could arrange to preserve them there was a danger that they would be lost to posterity. Explaining the quality of the workmanship in this engine. Mr. Kelting said even the nuts and bolts were hand-made, and the mechanics who dismantled it found they needed a different spanner for each nut!
"Wonderfully Good Service"
A representative of Pearsall & Co. told our reporter that the engine was used to drive part of the overhead shafting at the mill until a year or two ago. He said it had given wonderfully good service and there was no evidence of major repairs having been carried out. It has now been replaced bv electric motors. A similar steam engine which had been installed in Pearsall's Tancred-street mill was sold to Mr. Henry Ford about 20 years ago. It was dismantled, sent to America and reassembled in the world-famous Henry Ford museum at Dearborn. Michegan.
Cost of Installation
The cost of installation at the Taunton Castle museum is being met by public subscriptions, many of which were received after a broadcast bv Mr. Kelting. Another West Country firm has offered an electric motor to drive the engine so that the public may see it in action. Nearly £300 has been subscribed, but more is needed to pay for the skilled engineering task of installing the engine so that it may be seen at work. It would have been much simpler and cheaper to have put it in merely as a museum piece. The photograph, of the engine is reproduced by courtesy of the Keeper of the Museum, Mr. R. C. Sansome.'[1]
The photographs show some details of the engine’s construction.
Photo 1: The engine is a Woolf compound. The low pressure (LP) piston is connected to the end of the beam nearest the camera. The high pressure (HP) piston comes next, followed by the air pump shaft. The piston rods are connected to the beam by U-shaped straps. Their split bronze bearings are retained by these straps and by nicely-turned compression struts, the assembly being tightened by tapered cotters.
The three pairs of links are connected to each other by a pair of rods. The innermost pair of links is also linked to the horizontal girder (note the the two bolts at the bottom of the photo). This assembly provides the parallel motion mechanism needed to keep the piston rods vertical as they move up and down.
Photo 2: The method of tightening the bearings in the parallel motion 'radius arms' is unusual. Note that the bearing is cocked, perhaps due to excessive wear. The purpose of the collars or weights is not clear.
It might be expected that the horizontal cast iron beams seen in Photo 1 would simply continue under the beam's bearing pedestals. In fact the arrangement is more complicated, as will be seen in the following photos.
Photos 3 & 4: The structure sandwiched between the bearing pedestals and the fluted columns is a complex casting, bolted to the horizontal beam mentioned earlier. It may be apparent that the section nearest the camera has been cut through: this originally extended into the wall of the engine house, as did the corresponding section on the other side. This considerably stiffened the structure, but it did in theory make the cast iron framework of the engine susceptible to movement or settlement of the building. However, since the engine ran for a century, the designer’s confidence was well-founded!
Photos 5 & 6: Showing more detail of the castings used in this part of the assembly. Plenty of mental exercise for the patternmakers and foundry moulders.
Photo 7: The beam's pivot is a close fit in the hole in the beam, a move forward from the older method of having a bigger hole and 'staking' the pivot in place. This reflects the greater availability of suitable machine tools in 1850. The escaping rusty oil shows that some slackness has developed.
Photo 8: Cast iron connecting rod, with a simple but effect method of connection to the beam.
Photos 9 & 10: Note the repair to the bedplate, to the right of the main bearing.
Photo 11: The flywheel is cast in two halves. One of the joints at the rim can be seen here. There will be an internal tie bar, loose until the tapered cotters were driven in. The castings would tend to distort on cooling, so the way the two halves match almost seamlessly, on this unmachined casting, is quite impressive.
Photo 12: This shows the rod between the eccentric and the rocking lever which operates the engine's slide valves.
Photo 13: Showing the gab gear. The horizontal rod may be lifted to disengage it from the crankpin which works the valve operating gear. This would allow the valve gear to be moved manually for manoeuvring or reversing the engine (although it could not continue to run in reverse). However, this would require a handle for moving the valve gear, and there is no handle and no obvious provision for one. It may be that a open-jawed lever, like a spanner, would be applied to the rectangular-section crank. The shaft passes through the skirt of the HP cylinder and emerges on the other side, where a bell-crank transmits the movement to the slide valves. There is bruising on this bell-crank, and it may that some sort of spanner was applied here rather than on the other side.
Photo 14: There is an unused hole in the beam (centre of photo). This could have been used for working a pump, but it was probably always redundant (a 1938 photo shows it not being used[2])
Photo 15 & 16: Peering into the hole shows what might be a blowhole in the casting
Photo 17: The Pickering governor was added much later.