Abstract: In a thermostatic expansion valve having a thermo bulb, a valve opening degree is defined by the force difference between a first force at one side surface of a diaphragm and a second force at the other side surface thereof. The former force is the sum of the pressure of a refrigerant, sensed at the downstream side of a valve seat and applied on one side surface by an auxiliary pressure applying capillary tube, and the biasing force, applied on one side surface by a valve body spring. The latter force is the sum of the pressure of an actuator vapor, contained in a thermal bulb and applied on the other side surface of the diaphragm, and the pressure of the refrigerant, sensed at the upstream side of the valve seat in a refrigerant pathway of a valve housing and applied on the other side surface by way of a force transmitting member.

Abstract: A tool, used for forming a groove in a valve seat, having a tool main body which has a hardness greater than that of the valve seat, and an end portion with a circumferential surface which has a shape corresponding to the valve seat and is brought into linear or surface contact with the valve seat in an annular shape, and a wire which has a hardness greater than that of the valve seat and which is clamped between a circumferential edge of the valve seat and the end portion of the tool main body so as to cross the circumferential edge of the valve seat, wherein the tool main body is pressed until the circumferential surface of the end portion of the tool main body is brought into linear or surface contact with the valve seat in an annular shape and the movement of the tool main body is stopped, thereby forming an impression of the wire on the valve seat.

Abstract: A motor-driven expansion valve comprises a valve casing having a first passage, a second passage, and a communication passage having a valve seat and permitting the first passage to communicate with the second passage, a valve member provided within the valve casing and movable toward and away from the valve seat, bellows covering the area between the valve member and the valve casing and urging the valve member away from the valve seat, a drive screw disposed substantially in alignment with the valve member and threaded into the valve casing such that, by its rotational movement, it is moved in the same direction as the valve member to cause the valve member to be moved toward and away from the valve seat, a motor, a drive gear to which a rotational force is transmitted from the output shaft of the motor, and a driven gear which is concentrically mounted on the drive screw to be rotated with the drive screw and which meshes with the drive gear to receive the rotational force from the drive gear.

Abstract: A bimetal driven control valve comprises: a main body having an inflow channel, an outflow channel, and an orifice which connects the inflow channel and the outflow channel; a first bimetal which constitutes part of a tubular body, an outer portion of the bimetal being fixed to the main body; a second bimetal which constitutes part of the tubular body and whose outer circumferential surface is formed by the same metal used for the inner circumferential surface of the first bimetal, and whose inner circumferential surface is formed by the same metal used for the outer circumferential surface of the first bimetal, the inner circumferential surface of the second bimetal being opposed to the inner circumferential surface of the first bimetal: hinges for connecting respective ends of the first and second bimetals to form the tubular body; a value member which is mounted in the main body and which is connected to an outer portion of the second bimetal for moving the valve member between a first position at which th