Abstract: The present invention discloses an automatic self-adjusting thermally powered expansion valve for controlling the flow of refrigerant to an evaporator of a refrigeration system. The valve includes a differential fluid amplifier transducer which produces a constant flow of refrigerant independent of the liquid line pressure and includes a generally cylindrical interior with an inlet chamber having an inlet port and an outlet chamber having an outlet port and an orifice between the chambers providing a passage for the flow of refrigerant through the valve. The flow of refrigerant through the valve is regulated by a valve element, which moves longitudinally within the chambers with respect to the orifice. The longitudinal position of the valve element is controlled by force generators and sensors. The position of the valve element depends on the fluid pressure and the size of the pressure disks, and the spring constant of the compression spring.

Abstract: Method and apparatus are disclosed for controlling the pressure in a single compressor refrigeration system, comprising a timer for establishing a selected time period functionally related to the compressor on-off cycle, a pressure detecting means for establishing and detecting an operating suction pressure range in the system for determining when upper and lower limits of the operating pressure range have been exceeded, means for generating a compressor turn-on signal in response to exceeding the upper limit of the operating pressure range, means for generating a compressor turn-off signal in response to exceeding the lower limit of the operating pressure range, and control means receiving the compressor turn-on signal for applying the turn-on signal to the compressor in response to the suction pressure exceeding the operating pressure range upper limit, the control means receiving the compressor turn-off signal and cooperating with the timer for preventing the application of the turn-off signal to the compr

Abstract: Apparatus for capacity selecting compressor energization and deenergization in a commonly piped, multiple compressor system comprising largely compressor of unequal capacity wherein the minimum number of such compressors are cycled on/off together and wherein equal capacity compressors in the system are alternately selected to even the wear therebetween.

Abstract: A method and apparatus for initiating the defrost of refrigeration equipment on demand. A defrost clock which normally controls the conventional refrigeration and defrost modes of a refrigeration system includes an auxiliary switch to cease operation of the clock motor a predetermined time prior to normal defrost initiation. The defrost clock thus remains in the refrigeration mode until the demand defrost sensor switch, or an optional demand switch, initiates a defrost cycle of the refrigeration equipment. The closure of the demand defrost switch or the optional switches causes the defrost clock motor to run for a predetermined short period of time. The defrost clock switch subsequently closes slightly prior to initiation of a defrost to guarantee that the clock runs throughout the defrost mode. Thereafter, the defrost clock controls the length of the defrost and will terminate defrost upon a signal from a thermostat, or by a time signal, or a pressure signal.

Abstract: Foam plastic is injected into a hollow space between the inner and outer skin of a refrigeration unit. Contained in the foam plastic are metal plates positioned at points where walls, dividers or shelves may be attached to the refrigeration unit. The foam plastic hardens around the metal plates. Self taping screws drill through the skin, foam plastic and plate to rigidly attach structure being supported to the plate with a minimum amount of heat transfer through the foam plastic and metal plates.

Abstract: The electrical control panel for a refrigeration unit using single or three phase power. The control portion has an oil pressure safety switch, defrost timer, temperature controls and perhaps a refrigerant pressure control in conjunction with the normal internal overload circuit breakers for the compressor. After operation of the refrigeration unit for a period of time, a defrost control device cuts off the compressor and turns on the electric defrost heaters. As the evaporator coils are defrosted, defrost thermostats open the defrost heater supply circuits. When the current sensing relay senses that all the defrost heaters have been shut off via the defrost thermostats, a time delay relay will return the refrigeration unit to the normal refrigeration cycle. The same current sensing relay will prevent false triggering by the oil pressure safety switch if the compressor's internal overload circuit breaker opens.