Rider-Ericsson Engine Company

The company specialized in hot air pumping engines.

Mechanical energy is derived from a hot air engine as air is repeatedly heated and cooled, expanding and contracting, and imparting pressure upon a reciprocating piston.

The Reverend Robert Stirling is generally credited with the "invention" of the hot air engine in 1816 for his development of a "regenerator" which conserves heat energy as the air moves between the hot and cold sides of the engine.

As air in the hot side cylinder heats, it expands, driving the piston upward.

The air cools, contracts, and pulls the hot side piston downward.