Abstract: An expansion valve used in an air conditioner having a passage for a liquid-phase refrigerant sent from a reservoir to a valve body, and a passage for a vapor-phase refrigerant after passing an evaporator 8. The refrigerant passage includes a valve chamber to control the amount of the refrigerant passing through the valve by means of a member configured to engage with a valve seat. The valve member is operated by a valve driving rod which can move in the axial direction in response to the temperature and pressure of the vapor-phase refrigerant. An orifice is interposed between a liquid-phase refrigerant inlet port and the valve chamber to decrease that bubbles contained in the refrigerant entering into the valve chamber by means of its throttling hole. Also the passage from the valve chamber to the valve seat is tapered to prevent collapse of bubbles.

Abstract: A thermal expansion valve drives a valve body in a housing through a driving member by a gas pressure of a heat sensitive working fluid sealed in a power element, neighboring the housing, by a diaphragm. The driving member holds a heat ballast at its blind hole opened to the working fluid. A diaphragm has a center opening surrounded by a tubular projection, the diaphragm side end portion of the driving member is inserted in the opening, and a diaphragm catch is fitted on the outer periphery of the projection. The catch, the extended end of the projection and the end of the driving member are airtightly welded to each other.

Abstract: A power element-valve housing combined type thermal expansion valve has a diaphragm in an element and a driving member for driving a valve body in a housing by a diaphragm deflection. The diaphragm has a center opening surrounded by a tubular projection, the driving member has an outer flange coaxially supporting the diaphragm and a heat-balance containing blind hold opened to a heat sensitive working fluid in a sealed chamber in the element. A diaphragm catch fits on the projection's periphery and is airtightly welded with a coaxial annular ridge on a supporting surface of the flange to sandwich the diaphragm with the flange.