| 摘要 |
PROBLEM TO BE SOLVED: To provide an expansion device that has a simple structure and can prevent the breakage of a pipe of a high pressure section even if an abnormal increase in pressure occurs. SOLUTION: The expansion device comprises a differential pressure control valve of which the valve element 7 is lifted as differential pressure between pressure on the upstream side of a refrigerant and pressure on the downstream side, a spring 16 for energizing the valve element 7 in a valve closing direction, and a spring 17 for energizing the valve element 7 in the valve opening direction. The spring 17 is set to have a free length at a lift position of the valve element 7 when the differential pressure is a predetermined value. When the differential pressure is the predetermined value or less, a throttle passage cross-sectional area for the variation of the differential pressure is changed by synthetic loads of the springs 16 and 17, and normal throttle expansion is performed. When the differential pressure expands the predetermined value, the throttle passage cross-sectional area for the variation of the differential pressure is changed significantly by the load of only the spring 16, and more high-pressure refrigerants are relieved from the upstream side to the downstream side. COPYRIGHT: (C)2007,JPO&INPIT
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