Which engineer patented a high-pressure steam engine in 1802?

Richard Trevithick patented a high-pressure steam engine in 1802. Unlike atmospheric or low-pressure engines, his design used steam at several times atmospheric pressure to drive the piston directly, allowing a much smaller and lighter engine.

Trevithick’s work grew from Cornwall’s mining industry, where steam engines pumped water from deep workings. Improved boilers made higher pressures practical, and high-pressure operation eliminated the need for a separate condenser. That saved space and weight, making engines suitable not only for stationary machinery but also for vehicles and locomotives.

His 1802 patent was demonstrated by a stationary engine at the Coalbrookdale Company in Shropshire. The engine operated at an exceptionally high boiler pressure for its day—about 145 psi—and ran at roughly 40 piston strokes per minute. Trevithick later adapted the technology for locomotives.

James Watt is a common distractor because Watt greatly improved earlier steam engines, but his best-known engines were low-pressure designs. Oliver Evans also explored high-pressure steam in the United States, while Thomas Newcomen’s earlier engine was atmospheric.