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Crofton Pumping Station near the village of Great Bedwyn in Wiltshire, England supplies the summit pound of the Kennet and Avon Canal with water. The steam-powered pumping station is preserved and operates on selected weekends. It contains an operational Boulton & Watt steam engine dating from 1812 that is claimed to be the oldest working beam engine in the world in its original engine house and capable of doing the job for which it was installed.〔(Crofton Website About Page )〕 == Description == When the canal was built, no reliable water sources were available to fill the summit by normal gravitational means. However a set of usable springs were found adjacent to the canal route about one mile (2 km) east of the summit pound, and about 40 feet (12 m) below it. Arrangements were made for these springs to feed the pound below lock 60 at Crofton Locks. Some years later a reservoir (Wilton Water) was created to improve the supply to this pound, and this can now be seen across the canal from the pumping station. Water from below lock 60 was taken by a culvert to the foot of a well sunk from the pumping station, which is built on the hillside more than 40 feet (12 m) above the canal. The pumps take the water from this well and discharge it into a feeder channel next to the pumping station. The water flows along this channel under the force of gravity until it reaches the summit pound about one mile (1.6 km) to the west. For day-to-day operation, the pumping station now uses electric pumps, automatically controlled by the water level in the summit pound. However the original steam driven pumping equipment has been preserved and is still operational. A single Lancashire boiler provides steam to one or both of two beam engines. Number 1 engine, built by Boulton and Watt in 1812 and rebuilt as a Cornish engine in the 1840s, is a single-acting, condensing engine with a bore of 42.25 inches (1073 mm), a stroke of 7 feet (2134 mm) and indicated power of 38.6 horsepower (28.8 kW). It drives a 30-inch (762 mm) lift pump capable of lifting 2274 lb (1031 kg), or approximately one ton of water, per stroke, at a rate of 11 strokes a minute. Number 2 engine, built by Harvey and Co. of Hayle in 1846 as a double-acting Sims patent combined cylinder engine and rebuilt in 1903 to a Cornish Engine, is a single-acting, condensing engine with a bore of 42 inches (1067 mm), a stroke of 7 feet 8 inches (2337 mm) and indicated power of 42 horsepower (31 kW). It drives a 30-inch (762 mm) force pump capable of lifting 2235 pounds (1014 kg), or approximately one ton of water, per stroke, at a rate of 10.2 strokes a minute. When the Great Western Railway built its railway line through the area, it passed very close to the station and between it and the canal. Access between the canal side and the pumping station is now via a very low roofed tunnel. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Crofton Pumping Station」の詳細全文を読む スポンサード リンク
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