|The Original Installation
The first engine installed in the Engine House at Crofton was a second hand Boulton and Watt, purchased in 1802 from the West India Dock Company. This engine had a 90 cm (36 inch) diameter steam piston and a 2.5 m (8 foot) stroke. It had a wooden beam and worked a 66 cm (26 inch) diameter lift pump. It arrived at Crofton in 1807, and was at work by 1809.
The Engine House was designed to accommodate two engines and a second Boulton and Watt was ordered in 1810 and was installed and working by 1812. This one had a 107 cm (42 inch) diameter steam piston, and a 2.5 m (8 ft) stroke. It had a cast iron beam 8 m (26 feet) long weighing some 6 tonnes and worked a 76 cm (30 inch) diameter lift pump. Both engines were of typical Boulton and Watt design with parallel motion linkages and separate condensers installed below the valve gear on the steam cylinder side (‘ in-house ‘ side) of the beam wall. Steam was supplied by three ‘Waggon’ boilers at a pressure of 0.34 bar (5 psi).
Water from the Wilton natural springs fed the engine pound of the canal and the well in the station. There was a culvert from the engine pound to the well which maintained the supply of water for the pumps. The pumps raised this water 12 m (40 feet) and discharged it into the feeder channel.
As traffic on the canal increased, it was found that this water supply could not meet the demand, so in 1836, Wilton Water, a 3 hectare (8 acre) lake, was formed on land belonging to the Marquis of Ailesbury, by damming the valley opposite the Pumping Station. The water then ran over a weir into the engine pound of the canal and then through a culvert to the well beneath the pump house.
Mid-century Modernisation and the Great Western Railway
In search for improved efficiency, and with the Waggon boilers constantly in need of repair, in 1843, the Company contracted Harvey and Co. of Hayle in Cornwall for the supply of three Cornish boilers to work at about 1.4 bar (20 psi), and for the 107 cm (42 inch) engine to be fitted with new valve gear to cope with the increased pressure. When carrying out this work, Harvey’s also moved the condenser of the engine to its present position on the pump (‘out-house’) side of the beam wall in accordance with standard Cornish practice.
The first design of the Kennet & Avon canal by the distinguished Scottish civil engineer, John Rennie, called for a 4.5 km (2.5 mile) tunnel between the Wiltshire villages of Crofton and Burbage but, in those days, tunnelling was a very expensive and uncertain process and a cheaper alternative was sought…….
|1896 – 1905 The Final Changes
In 1896 the No.1 engine (Boulton and Watt) suffered a major failure. With the No.2 engine now derelict, this caused a problem in keeping the canal open, and GWR were forced to do something about it as they had legal obligations to maintain the waterway……..
|1905 – 1968
Both engines were in regular service until 1952, and the 1812 Boulton and Watt continued to be used spasmodically until 1959, when, due to deterioration, the top 11 m (36 feet) of the chimney were removed making it impossible to fire the boilers as there was not enough draught……..
On 14th April 1968, Crofton Pumping Station was purchased by the Kennet and Avon Canal Trust from British Waterways for £75 with the objective of restoring it to full working order. An appeal for funds was launched and a team of volunteers, including several qualified engineers began planning the work to restore the building, boilers and engines………
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