1905 15 HP Bessemer/Struthers-Wells on display at the Coolspring Power Museum.
This 1905 15 HP Bessemer/Struthers-Wells steam-to-gas conversation features a heavy five-spoke flywheel.
Manufacturer: Struthers-Wells Co.,Warren, Pa.; Bessemer Gas Engine Co., Grove City, Pa.
Serial Number: 4093
Ignition: Hot tube
This is a Struthers-Wells steam engine converted to operate as a 2-stroke gas engine with the fitting of a Bessemer conversion cylinder.
Bessemer was one of the early pioneers of making conversion cylinders. They started out as the Carruthers and Fithian Clutch Co., so in the conversion kit, which normally included a cylinder assembly and a new piston and clutch, they already had the clutch developed.
In this engine’s design, there is a pendulum-style governor that’s operated by a pushrod on an eccentric on the crankshaft.
Depending on the engine speed, the pendulum allows a gridiron valve on the transfer port to either open or not open, thereby limiting engine speed. “It was perhaps more of an overspeed governor rather than something you would use to precisely control the speed at which the engine operated,” Coolspring President Clark Colby says.
Most converted engines began as steam drilling engines, but this engine began life as a commercial, heavy duty steam engine. It was made by Struthers-Wells Co., but it wasn’t originally made for oil well service. “It has a heavier five-spoke flywheel that’s not typical of oil field use,” Colby says.
“It has a very heavy disc-style crankshaft, which you almost never saw in the oil field, and a fairly heavy base. It’s likely this engine was designed to power something in a machine shop or perhaps a sawmill. It was probably sold as a used engine, purchased by an oil producer, converted and spent the rest of its life at a well somewhere.”
Read more about this engine and 38 others in the book, Coolspring, and published by Gas Engine Magazine.