Gas appliance control valve - gives thermo-mechanical or electromechanical actuation in same housing using preloading spring on main valve

摘要

A change-over valve for a servo-controlled gas appliance includes a main gas valve which is preloaded by a spring in the closing direction and lies between the gas inlet and outlet to the burners in a housing. Its diaphragm actuator is controlled by a pressure control valve. The housing also contains a recess. In the version shown, this recess accepts a mechanical drive for the rocker with the closing elements. This is controlled by a liq-filled temp. probe which acts through a capillary on the diaphragm actuator for a snap spring.