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Six-column beam engines are a means of constructing a beam engine, where the beam's central pivot is supported on a cast iron frame or 'bedstead', supported on six iron columns. ==History== These engines were a development after the house-built engine. Their cast iron frames could be built and test-assembled at a factory before delivery, allowing rapid assembly or 'erection' once on site. Their main advantage was that they avoided the need for complex masonry foundations in their engine house, merely a simple level platform to which the iron frame could be bolted. The difficult alignment between their cylinder, the beam pivot and the crankshaft was all taken care of by the factory-made frame.〔 Although the upper part of the frame only supports the beam's central pivot and any Watt's parallel motion gear, it also has an important function in stiffening the frame overall against vertical bending forces between the cylinder and crankshaft. Cast iron is weak against bending and a shallow frame alone would need either rigid masonry support, or would soon fracture. One of the oldest surviving six-column engines is a small engine of 1820, possibly by Boulton & Watt, preserved at the Birmingham Museum of Science and Industry. Another six-column engine was within that collection, an Easton & Amos engine of 1864. This engine is rather larger and a Woolf compound. Six-column engines were most popular for the smaller sizes of engine. They were all rotative beam engines, with a flywheel and rotating output shaft. These were used to drive machinery, as diverse as sugar cane crushing mills, winding engines in coal mines and sawmills. Many beam engines, working into the late 20th century,〔The six pumping engines of the Severn Tunnel at Sudbrook were only replaced in 1962.〕 were non-rotative and drove vertical water pumps directly. These did not use the six column layout. The small six-column engine may be considered as an early form of semi-portable engine.〔 Its pre-fabricated nature and avoidance of foundations made it quicker, thus cheaper, to first install. It also encouraged the re-use of engines on other sites. The small Birmingham engine is known to have worked on at least three different sites as a winding engine, grinding fireclay and finally as a farm chaff cutter, a working life of around 130 years.〔 The Cobb's Brewery engine (1825) at Margate was one of a batch built for a sugar plantation in the West Indies, but owing to their bankruptcy before shipping it was sent instead to South America. Its ship then foundered on the North Foreland and it was purchased from the wreck for use locally. The versatility of this design meant that they could be used easily by a variety of industries. 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「Six-column beam engine」の詳細全文を読む スポンサード リンク
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