Thermostatic expansion valve

摘要

A thermostatic expansion valve located at the inlet of an evaporator in the refrigeration apparatus has a valve housing supporting a diaphragm in its sealed space. Pressure from a thermal bulb is applied on the upper surface of the diaphragm, and pressure of a reduced-pressure refrigerant in the inlet of the evaporator is applied on the lower surface of the diaphragm through on equalizing signal passage extending from a refrigerant passage formed in the housing to the sealed space in the housing. In the refrigerant passage, a valve seat is formed. The equalizing signal passage is opened at the passage in the downstream side of the valve seat. A sectional area of the refrigerant passage between the passage side opening of the signal passage and the valve seat is larger than that of the refrigerant passing hole of the valve seat but smaller than that of the refrigerant passage at a position remoter from the valve seat than the passage side opening of the signal passage.