Bernard Collyer’s


This fascinating Corliss valved stationary mill steam engine was built by Bernard Collyer. It was displayed at the last Model Engineer Exhibition at Sandown Park in 2014.

Corliss engines were fitted with rotary valves and variable timing patented in 1849 by American engineer George Corliss. Engines fitted with Corliss valve gear offered the best thermal efficiency until the refinement of the uniflow steam engine and steam turbine in the 20th century. Corliss engines were generally about 30 percent more fuel efficient than conventional steam engines. This increased efficiency made steam power more economical than water power, allowing industrial development away from millponds and lodges.

Corliss engines were used to provide power to line shafting in factories and mills and to drive dynamos to generate electricity. Many were quite large, developing several hundred horsepower turning massive flywheels weighing several tons at about 100 rpm. Some remain in service.

An engine design and castings of this type is available from Southworth Engines.