Abstract: The invention entails the use of a positive displacement pump (41) magnetically coupled to a drive motor (42) located in a conduit arrangement (60) which is parallel to the liquid line (22) of the refigeraton system as in FIG. 5. This parallel conduit arrangement (60) also includes a pressure regulating valve (45) that will regulate the amount of pressure added to the liquid line (22) by the parallel pump and piping arrangement (60). In addition, a check valve (47) is located in the liquid line (22) to maintain the pressure differential added to the liquid line. This parallel piping arrangement (60) is desirable in order to allow a constant predetermined pressure to be added to the liquid line regardless of variations in flow rate of the liquid refrigerant. The present invention involves the use of a controlled variable speed drive on the pump meter so the flow rate through the pump will more closely match the variable system flow.

Abstract: The invention entails the use of a positive displacement pump (4) magnetically coupled to an drive motor (42) located in a conduit arrangement (60) this is parallel to the liquid line of the refrigeration system as in FIG. 5. This parallel conduit arrangement also includes a pressure regulating valve that will regulate the amount of pressure added to the liquid line by the parallel pump and piping arrangement. In addition, a check valve (47) is located in the liquid line to maintain the pressure differential added to the liquid line. This parallel piping arrangement (60) is desirable in order to allow a constant, pre-determined pressure to be added to the liquid line regardless of variations in flow rate of the liquid refrigerant. In addition, the parallel piping arrangement allows the system to operate without liquid line obstruction in the event of pump failure.

Abstract: A compression-type refrigeration system is disclosed, in which "flash gas" formation is eliminated without artificially maintaining condenser temperature and pressure levels. Condenser temperatures and pressures are allowed to fluctuate with ambient operating conditions, resulting in reduced compressor load and increased refrigeration capacity. After condensation, liquified refrigerant in the conduit between the receiver and the expansion valve is pressurized without adding heat, by means of a combination of (a) a positive-displacement pump, in parallel with the conduit, (b) a bypass conduit pressure regulating controller, and (c) a check valve in the conduit, to a pressure sufficient to suppress flash gas in the conduit. A variable speed liquid injection pump is provided to inject liquid refrigerant from downstream of the positive-displacement pump to upstream of the condenser, at a controlled rate sufficient to desuperheat the refrigerant upstream of the condenser.

Abstract: A compression-type refrigeration system is disclosed, in which "flash gas" formation is eliminated without artificially maintaining condenser temperature and pressure levels. Condenser temperatures and pressures are allowed to fluctuate with ambient operating conditions, resulting in reduced compressor load and increased refrigeration capacity. After condensation, liquified refrigerant in the conduit between the receiver and the expansion valve is pressurized without adding heat, by means of a combination of (a) a positive-displacement pump, in parallel with the conduit, (b) a bypass conduit pressure regulating controller, and (c) a check valve in the conduit, to a pressure sufficient to suppress flash gas in the conduit. A variable speed liquid injection pump is provided to inject liquid refrigerant from downstream of the positive-displacement pump to upstream of the condenser, at a controlled rate sufficient to desuperheat the refrigerant upstream of the condenser.