| 摘要 |
There is provided a flow rate control valve of a constant flow-rate control type, which is simple in construction. The flow rate control valve is configured, by regarding a evaporator as a restriction passage, to include a constant differential pressure control valve for controlling the differential pressure before and after pressure loss caused by passage of refrigerant through the evaporator to be substantially constant. In the constant differential pressure control valve, a valve element receives pressure from the outlet of the flow rate control valve in a valve-closing direction, and a piston receives pressure from the outlet of the evaporator in a valve-opening direction. By controlling the differential pressure between pressure at the inlet of the evaporator and the pressure at the outlet of the evaporator such that it is substantially constant, the constant differential pressure control valve causes the refrigerant to flow into the evaporator at a constant flow rate dependent on electric current that energizes a solenoid. This makes it unnecessary to form a restriction passage in the flow rate control valve, and hence the construction of the flow rate control valve can be simplified, which makes it possible to provide a flow rate control valve manufactured at low cost.
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