| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost expansion device capable of changing a restriction passage cross-sectional area according to the pressure and temperature of an introduced refrigerant without having a hermetically sealed high-pressure space. SOLUTION: The expansion device comprises a differential pressure valve 2 the valve lift of which is controlled according to the differential pressure across the expansion device, and a temperature sensing section 3 for further controlling the valve lift according to the temperature of the refrigerant. The differential pressure valve 2 has a piston 8 having an outer diameter larger than a valve element 6 and formed integrally with the valve element 6. The piston 8 defines a pressure adjusting chamber 11 into which the inlet pressure is introduced via a pressure passage 12. When the inlet pressure becomes high, the differential pressure valve 2 operates in a valve opening direction. The temperature sensing section 3 contains an axially expandable bellows 14 filled with wax 16 having a large coefficient of thermal volumetric expansion such that the differential pressure valve 2 operates in a valve closing direction when the inlet temperature of the refrigerant becomes high. COPYRIGHT: (C)2007,JPO&INPIT
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