Heat-engine plant for air-conditioning valve operation - opens and closes flaps by selective heating of wax in opposed piston engines controlled by thermostat

摘要

The valve or flap (10) associated with each cooled or ventilated compartment is rotated by a shaft (11) coupled to a reciprocating slider (19) driven by rods (17, 18) from oppositely acting heat engines (13, 14) using wax as working substance. Travel is limited by end stops (20, 22). The coupling (23) carries a cam (24) actuating a rocker switch (26) in circuit with PTC thermistors (18) on each heat engine (13, 14) and with a thermostat (28) energising (29, 30) each heat engine in turn. USE/ADVANTAGE - Refrigerator and freezer cabinets with four or more compartments. Simple mechanism, reliable operation.