A beam engine is a type of steam engine where a pivoted overhead beam is used to apply the force from a vertical piston to a vertical connecting rod. This configuration, with the engine directly driving a pump, was first used by Thomas Newcomen around 1705 to remove water from mines in Cornwall. The efficiency of the engines was improved by engineers including James Watt, who added a separate condenser; Jonathan Hornblower and Arthur Woolf, who compounded the cylinders; and William McNaught, who devised a method of compounding an existing engine. Beam engines were first used to pump water out of mines or into canals but could be used to pump water to supplement the flow for a waterwheel powering a mill.
The cast-iron beam of the 1812 Boulton & Watt engine at Crofton Pumping Station – the oldest working, in situ example in the world
Back of Museum De Cruquius near Amsterdam, an old pumping station used to pump dry the Haarlemmermeer. It shows the beams of the pumping engine and the 9 meter drop in water level from the Spaarne river. The beam engine is the largest ever constructed, and was in use till 1933.
The remains of a water-powered beam engine at Wanlockhead
A small rotative beam engine, built in 1870 by Thomas Horn to a design by James Watt. The crank is visible at the front, the flywheel part-hidden by the engine. (Originally installed in a waterworks in Ashford, now operational and preserved at the Bredgar and Wormshill Light Railway.)
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be transformed, by a connecting rod and crank, into rotational force for work. The term "steam engine" is most commonly applied to reciprocating engines as just described, although some authorities have also referred to the steam turbine and devices such as Hero's aeolipile as "steam engines". The essential feature of steam engines is that they are external combustion engines, where the working fluid is separated from the combustion products. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term steam engine can refer to either complete steam plants, such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary steam engine.
A model of a beam engine featuring James Watt's parallel linkage for double action
A mill engine from Stott Park Bobbin Mill, Cumbria, England
A steam locomotive from East Germany. This class of engine was built in 1942–1950 and operated until 1988.
A steam ploughing engine by Kemna