The weight is lifted by a combination of steam pressure above, and vacuum below, the piston.ĭuring the pumping stroke, as the weight falls, the piston returns to the top of the cylinder because an equilibrium valve opens to allow steam to pass from above to below the piston. This weight is positioned above the pump, which is linked to a beam, with the piston attached to the opposite end of this beam. The main characteristic of a Cornish engine is that pumping is done by a falling weight which is lifted by the engine.

The term “Cornish” refers to the operating cycle of these engines, although three in the museum collection were also manufactured in Cornwall. The museum also acquires items associated with water. In addition to these engines, we have also collected examples of diesel, electric, water and animal powered pumping engines. Together the collection demonstrates the major developments in steam engine technology. Visit our What's On to find out when our engines are next in steam. These comprise the Cornish engines, which are in their original engine houses, and the rotative engines, which have been collected by the museum trust from pumping stations across the country. The heart of the museum is its collection of magnificent steam pumping engines.

Steam firewatch background