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 evaporators. 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.

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 method and apparatus for controlling the operation of a refrigeration system, for example, is provided which includes a first sensor for monitoring the sump temperature of a compressor used in conjunction with the refrigeration system, and a second sensor which monitors compressor ambient air temperature. The refrigeration system includes an electrically operable expansion valve and the sensors are employed in a control device operatively connected to the electrically controlled expansion valve to control the operating position of that valve. Refrigeration system operation can be controlled precisely, thereby maximizing the efficiency of the system, by monitoring the sump temperature and ambient temperature of the compressor.

Abstract: A refrigeration system is provided with an improved frost detector for detecting frost on an evaporator coil of the system. The detector includes a saddle mounting structure adapted for direct mounting to the tubular coils conventionally employed in condensers and evaporators of refrigeration systems. An energy source and a sensor carried by the mounting structure are positioned on opposite sides of the tubular coil. The sensor is irradiated by the energy source until frost growth on the coil tube obstructs the line of sight path between the source and the sensor. Means are provided for adjusting the line of sight path with respect to the coil tube so that the thickness of frost permitted to accumulate before defrost actuation can be varied for particular applications. By utilizing a narrow beam device as an irradiation source, very precise control of the defrost cycle can be obtained.

Abstract: A control valve is provided with environmental temperature compensation. Preferably, the valve is an electrically operated device having a valve member mounted for movement between at least first position and a second position. Means for electrically operating the device includes heater means interleafed with bi-metallic discs so that electrical energy input to the heater means controls disc expansion and contraction, thereby controlling physical position of the valve member. In a stand alone version of the control valve, a sensor is operatively connected between the bi-metallic discs and an electrical control means. The electrical control means is adapted to compare the signal generated by the sensor with a predetermined set point for controlling electrical energy input to the heater means. The control means regulates that electrical input until equality of comparison is attained.

Abstract: A method and apparatus for controlling the operation of a refrigeration system, for example, is provided. Refrigeration systems commonly include a compressor, an evaporator coil, a condensing coil and an expansion valve inserted in the refrigeration line between the evaporator coil and the condensing coil. In the preferred form of the invention, an electrically controlled expansion valve is operatively connected to control means. The control means includes a pair of sensors. The control means is used to control expansion valve operation so that evaporator operation is maximized, regardless of load on the system. Control is accomplished, in one embodiment, by sensing the temperature along two points of the evaporating coil, and using the control means to maintain a predetermined temperature relationship between the two points.

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.