(under subclass 490) Subject matter including means responsive to the pressure within the space or material heated or within the control means itself, due to a change of condition therein, whereby the current supplied to the heating device is regulated, or controlled.
SEE OR SEARCH THIS CLASS, SUBCLASS:
287, for liquid in circuit heaters with resistance path automatically responsive to pressure.
332, for liquid heaters with current control means responsive to hydrostatic or vapor pressure.
333, for liquid heaters with current control responsive to liquid level.
SEE OR SEARCH CLASS
165, Heat Exchange, 281+, for pressure responsive control devices for heating or cooling systems.
200, Electricity: Circuit Makers and Breakers,
81+, for fluid pressure operated electric switch structures.
307, Electrical Transmission or Interconnection Systems,
118, for fluid pressure controlled switching system and subclass 144 for fluid pressure actuated switches.
