Abstract: Apparatus for and a method of automatically adjusting the superheat setting of a thermostatic expansion valve of a refrigeration system is disclosed in which the superheat of the refrigeration system is maintained at a low superheat level so as to maximize the operating efficiency of the refrigeration system, and yet which prevents the return of excessive amounts of liquid refrigerant to the compressor which would be likely to cause damage to the compressor.

Abstract: A pulse controlled refrigeration expansion valve and method of controlling the valve is disclosed. The valve is preferably an on/off (open/closed) direct controlled solenoid valve. The valve is periodically energized (opened) and de-energized (closed) in response to a refrigeration system parameter (e.g., superheat) such that the ratio of energization time/de-energization time during each period of operation of the valve is varied in response to the system parameter(s) and such that the on/off solenoid valve functions as a modulated refrigerant flow control expansion valve.

Abstract: A four way valve assembly is provided which includes a main valve member operable by independent pilot valve actuation. The independent pilot operation means that the main valve stroke can be varied over a relatively wide range, enabling the valve to be produced in a number of sizes without requiring redesign of the pilot valve portion of the valve. A pilot body is mounted to the main valve and has a movable plunger of a conventional solenoid actuator attached to it. The plunger extends within the pilot body and has a loose fitting pilot slide mounted to its free end. The relative loose fitting pilot slide reduces the need for close manufacturing tolerances for the component parts used in constructing the pilot valve portion of the valve. The pilot slide is maintained in sealed relationship with a wall of the pilot body by relatively high pressure fluid passing through the pilot valve body.

Abstract: A pilot controlled, diaphragm actuated valve having simplified construction is provided which is capable of maintaining a variety of valve operating positions. In the preferred embodiment, the valve pin is controlled precisely with respect to the pilot opening in the diaphragm to permit modulation of the diaphragm position. Control of the valve pin is maintained through the use of a power assembly which positions the valve pin in accordance with some sensed system variable. The valve includes structure for reducing instability of the valve over the valve operating range.

Abstract: A four way valve assembly is provided which includes a main valve member operable by independent pilot valve actuation. The independent pilot operation means that the main valve stroke can be varied over a relatively wide range, enabling the valve to be produced in a number of sizes without requiring redesign of the pilot valve portion of the valve. A pilot body is mounted to the main valve and has a movable plunger of a conventional solenoid actuator attached to it. The plunger extends within the pilot body and has a loose fitting pilot slide mounted to its free end. The relative loose fitting pilot slide reduces the need for close manufacturing tolerances for the component parts used in constructing the pilot valve portion of the valve. The pilot slide is maintained in sealed relationship with a wall of the pilot body by relatively high pressure fluid passing through the pilot valve body.

Abstract: A four-way valve assembly is provided which includes a main valve member operable by pilot valve actuation. A particular feature of the construction of the valve assembly is that the main valve member stroke length may vary over a relatively wide range, enabling the valve to be produced in a variety of sizes, without affecting the pilot valve operation. The main valve member includes a first side and a second side. The first side of the main valve member has a hollow formed in it, while the second side has a flat area formed in it. The flat area is utilized to mount a pilot assembly to the valve. Means for operating the valve assembly are operatively connected to the pilot assembly so as to permit the pilot assembly to move with the main valve while the operating means remains stationary. All connections required for operation of the main valve are carried internally of a valve enclosure.

Abstract: A pulse controlled refrigeration expansion valve for multiple evaporators and method of controlling the valve is disclosed. The refrigeration system on which this invention is typically used includes a single source of pressurized refrigerant and a plurality of .[.evaportors.]. .Iadd.evaporators.Iaddend.. Each evaporator has an expansion valve associated therewith which is preferably an on/off (open/closed) direct controlled solenoid valve. The valve is periodically energized (opened) and de-energized (closed) in response to a parameter (e.g., superheat) of its respective evaporator such that the ratio of energization time/de-energization time during each period (e.g., 4 seconds) of operation of the valve is varied in response to the system parameter(s) and such that the on/off solenoid valve functions as a modulated refrigerant flow control expansion valve. A temperature sensor is provided which senses the temperature of the space being refrigerated by a respective evaporator (e.g.