William McNaught (1813–1881) was a Scottish engineer, from Glasgow, who patented a compound steam engine in 1845. This was a technique of improving the efficiency of a standard simple Boulton & Watt beam engine. The engine was compounded by adding a high-pressure cylinder between the support column and the flywheel, on the side opposite the low-pressure cylinder. This improvement could be retrospectively fitted to existing engines.
___Beam_engine_q.jpg)
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 rotative beam engine is a later design of beam engine where the connecting rod drives a flywheel by means of a crank (or, historically, by means of a sun and planet gear). These beam engines could be used to directly power the line-shafting in a mill. They also could be used to power steam ships.