Crofton Pumping Station
Grafton, Wiltshire KAC34.53
KandAC mile 34
Crofton Pumping Station from across the canal.
The summit pound of the canal is across chalk downland where water is scarce; every boat leaving this summit pound uses a lockful of water, washing away. Water is available from springs near Wilton village. It is impounded in Wilton Water which is used to feed pumping engines which lift the water 40ft to summit level. There are two beam engines at Crofton; the first was built 1801 and installed here to start work 1809, the second engine started 1812, built by Boulton and Watt. The 1812 engine was converted to the Cornish Cycle, with a higher steam pressure, in 1845. A replacement for the 1809 engine was installed 1846-47, a Sims combined engine supplied by Harvey and Co, Hayle, Cornwall, re-using the Boulton and Watt parallel motion from the 1809 engine. At first there were low pressure wagon top boilers, steam at 4.5psi; these were replaced in 1845 by Cornish boilers in 1845, steam at 10psi; and today there are Lancashire boilers fitted by the Great Western Railway, providing steam at 20psi. Water is lifted 40ft from the inlet and runs from here by Crofton Feeder, along a contour on the north side of the railway. It feeds into the canal on the upper side of lock 55, Crofton Top Lock.
Water is taken off by the pumps from the off side of the canal, under the railway, and so on.
Large engines need large tools.
Parallel motion connecting piston and beam end.
Parallel motion connecting piston and beam end.
The piston rod must go straight up and down, or damage the cylinder, the end of the beam must of necessity move in a curve. James Watt invented an approximate 'parallel motion' to connect these two essential elements of a steam engine in 1784. An exact parallel linkage was not invented until Peaucellier, 1864.
Cundy, H M & Rollet, A P: 1957: Mathematical Models: Oxford University Press
Cylinder head etc.
The beam, part of it!
Safety valve?
Safety valve on the boiler, and insulating brickwork.
Fire door.
Sight glasses, water gauges for the boiler.
One of the boilers installed by the Great Western Railway, GWR, Swindon Works, Wiltshire.
One of the boilers installed by the Great Western railway, Swindon Works, Wiltshire.
Safety valve and other clutter atop a boiler.
The pumping station chimney is built in header bond brickwork bound with wrought iron - probably steel nowadays, and much repaired.
So - it's a cliche - what else do you photograph? The chimney is 20ft or so shorter than it was, to make it safer, and has an electric fan to help the draught.
Nowadays you can see the smoke when the engines are in steam. When built the engines had to 'consume their own smoke' or the engineman would be sacked, as stipulated by the Earl of Ailesbury who lived at Tottenham Park a mile or so NW.
Bradley, Ian: 1952 (June): Crofton Beam Engines: Model Engineer

Kennet and Avon Scrapbook 2000