Abstract: A bulbless expansion valve including a valve body, a valve member, a power element, and a thermal sensor including an enclosure operatively mounted to the valve body. The power element includes a diaphragm having a first side operatively coupled to the valve member, and a second side that together with the sensor enclosure forms at least part of a sensing chamber containing sensing fluid such that the sensing fluid is in communication with the second side of the diaphragm. The first side of the diaphragm may be fluidly coupled to an operating line, such as a suction line, to communicate temperature and pressure to the first side of the diaphragm, thereby providing heat transfer with the sensing fluid on the opposite side. Temperature changes of the sensing fluid results in pressure changes applied to the diaphragm causing movement of the valve member to control flow of the operating fluid.

Abstract: A bulbless expansion valve including a valve body, a valve member, a power element, and a thermal sensor including an enclosure operatively mounted to the valve body. The power element includes a diaphragm having a first side operatively coupled to the valve member, and a second side that together with the sensor enclosure forms at least part of a sensing chamber containing sensing fluid such that the sensing fluid is in communication with the second side of the diaphragm. The first side of the diaphragm may be fluidly coupled to an operating line, such as a suction line, to communicate temperature and pressure to the first side of the diaphragm, thereby providing heat transfer with the sensing fluid on the opposite side. Temperature changes of the sensing fluid results in pressure changes applied to the diaphragm causing movement of the valve member to control flow of the operating fluid.

Abstract: A thermal sensing bulb (102) for an expansion valve (104) in a refrigerant system, the bulb containing a ballast material (108), the ballast material including alumina. More particularly, the ballast material (108) includes alpha alumina, which may be in the form of a plurality of discrete particles having a desired surface area, particle size, and/or particle size distribution.