Abstract: A method of defrosting a refrigeration system having a main compressor connected by a main hot gas discharge line to a condenser, the condenser being connected by a main liquid line to thermal expansion valves and subsequent cooling coils, each thermal expansion valve and cooling coil being in parallel connection with the other thermal expansion valves and cooling coils, and each cooling coil being connected by a suction line to the main compressor, the defrosting method includes passing hot gas from the main hot gas discharge line through a selected cooling coil to defrost same, compressing cooled hot gas which has passed through the cooling coil by means of a separate dedicated defrost compressor, and returning the compressed hot gas to the main hot gas discharge line.

Abstract: A refrigeration system has an evaporator compartment containing a refrigeration evaporator and a refrigeration heat exchanger, a liquid line for conveying liquid refrigerant from a compressor through the heat exchanger to the evaporator, and a suction line for conveying vaporized refrigerant from the evaporator through the heat exchanger in heat exchange relationship with the liquid refrigerant flowing therethrough to a compressor. The refrigeration system also has a compartment to be cooled, and an air flow passage associated with the compartment for cooling thereof, the air flow passage passing through the evaporator compartment whereby the air flow passes over the liquid line and evaporator, the liquid line being thermally insulated from the air passing thereover. The refrigeration system may be used in a refrigerated merchandising display case.

Abstract: A refrigeration system has a compressor operable to supply relatively hot compressed refrigerant gas, a condenser to liquify the relatively hot compressed refrigerant gas from the compressor, a thermostatic expansion (TX) valve to vaporize liquified refrigerant from the condenser, an evaporator to cool the surrounding atmosphere by vaporized refrigerant from the TX valve, a superheat sensor to improve control of the TX valve, a compressor discharge line to convey relatively hot compressed refrigerant gas from the compressor to the condenser, a liquid line to convey liquified refrigerant from the condenser to the TX valve, and a suction line including the superheat sensor to convey vaporized refrigerant from the evaporator to the compressor.

Abstract: A refrigeration system has a compressor operable to supply compressed refrigerant vapor, a condenser to liquify compressed refrigerant vapour from the compressor, a thermostatic expansion valve to vaporize liquified refrigerant from the condenser, an evaporator to cool the surrounding atmosphere by vaporized refrigerant from the thermostatic expansion valve, a superheat sensor to improve control of the thermostatic expansion valve, a compressor discharge line to convey compressed refrigerant vapour from the compressor to the condenser, a return line to convey liquified refrigerant from the condenser to the expansion valve, and a suction line including the superheat sensor to convey vaporized refrigerant from the evaporator to the compressor.

Abstract: This invention provides a full flow vaporizer for use in a refrigeration system (which may be part of a heat pump) employing hot gas from the compressor to periodically defrost the cooling coil or coils. The vaporizer usually consists of three concentric circular cross-section tubes, the innermost tube receiving the fluid from the coil and being divided about midway along its length by a disc transverse barrier into first and third chambers. The cylindrical wall of the first chamber is provided with a plurality of holes directing the fluid forcefully radially outwards into a second chamber between the innermost and middle tubes and against the inner wall of the middle tube, which is heated by hot refrigerant gas passing in a fourth chamber between the middle and outermost tubes, the fluid then passing from the second chamber into the third chamber through a similar plurality of holes in the innermost tube cylindrical wall.

Abstract: A new device is provided for sensing refrigerant tempertatures in refrigerator systems, and for the control of refrigerant loading in a plurality of refrigerator evaporator circuit coils connected in parallel. Such evaporator coils are supplied with refrigerant through a termostatically controlled flow control valve, which is controlled by a sensor to ensure a predetermined amount of superheat. The usual minimum superheat is aobut 5.5.degree. C. (10.degree. F.) and to reduce this value the refrigerant is passed through the devide in which it is rendered thoroughly turbulent and mixed, the device intercepting the entire refrigerant flow just before the sensing of the superheat, thus ensuring that the temperature is accurately measured. In one aspect of the invention the device consists of a series of three chambers connected together by two similar sets of holes, the first and third chambers being similar so that it is completely reversible.

Abstract: A new method and apparatus are provided for sensing refrigerant temperatures in refrigerator systems, and for preventing underloading of the coil, or of any of the coils in a plurality of refrigerator evaporator circuit coils connected in parallel. The usual thermostatically controlled refrigerant flow control valve is controlled by a thermostatic sensor to ensure a predetermined minimum amount of superheat, usually about 5.5.degree. C. (10.degree. F.). To avoid underloading the refrigerant is rendered thoroughly turbulent and mixed, and in the multi-coil evaporator the flows from all of the coils are similarly thoroughly turbulated and mixed, by a turbulating and/or mixing device that intercepts the entire refrigerant flow just before the sensing of the superheat, thus ensuring that the temperature is accurately measured; in the multi-circuit coil system the device averages the temperatures of all the flows. Different turbulator/mixer devices are described and two or more such devices may be used in series.