US Patent 10415844 Low powered pneumatic control converter

A pneumatic control converter, preferably acting as a pneumatic thermostat, includes a pneumatic section, and electronic section and a piezo electric linkage section. A piezo electric rotary motor drives a rotary cam, with a cam follower linked via a W-shaped flexure linkage to bias the ball nozzle which controls the pneumatic control output pressure. The input to the piezo electric rotary motor is an electrical signal dependent upon electronically sensed pressure relative to the programmed set point. The pneumatic control converter consumes little electrical energy and is preferably battery powered, and the pneumatic control output pressure can be maintained even in the absence of electric power.