Heated receiver winter control for refrigeration systems

Claim 1

A REFRIGERATION SYSTEM ADAPTED FOR USE UNDER A WIDE VARIETY OF AMBIENT CONDENSER TEMPERATURES, SAID SYSTEM COMPRISING A CIRCUIT FOR REFRIGERANT FLOW INCLUDING CONDUIT INTERCONNECTED COMPRESSOR, CONDENSER, EVAPORATOR AND A VARIABLE ORIFICE EXPANSION DEVICE IN OPERATIVE ASSOCIATION WITH THE EVAPORATOR INLET, A LIQUID LINE INTERCONNECTING THE CONDENSER OUTLET WITH SAID EXPANSION DEVICE, A REFRIGERANT RECEIVER HAVING ELECTRICAL HEATER MEANS THEREIN FOR ELEVATING THE TEMPERATURE AND PRESSURE IN SAID RECEIVER UPON ENERGIZATION OF THE HEATER MEANS, SWITCH MEANS HAVING MEANS RESPONSIVE TO REFRIGERANT PRESSURE CONDITIONS IN A PORTION OF THE SYSTEM FROM THE CONDENSER OUTLET TO THE RECEIVER TO DETECT OCCURRENCE OF RECEIVER PRESSURE BELOW A SELECTED LEVEL AND ENERGIZE SAID HEATER MEANS, A FIRST LIQUID PASSAGE CONNECTING SAID RECEIVER WITH SAID LIQUID LINE FOR PASSAGE OF LIQUID REFRIGERANT THEREBETWEEN, A SECOND LIQUID PASSAGE CONNECTING SAID RECEIVER WITH SAID LIQUID LINE AT A POINT RELATIVELY MORE REMOTE FROM THE CONDENSER OUTLET THAN SAID FIRST PASSAGE FOR PASSAGE A LIQUID REFRIGERANT THERETHROUGH, VALVE MEANS HAVING VALVE MEMBERS IN AT LEAST ONE OF SAID PASSAGES AND IN SAID LIQUID LINE MOVABLE TO OPEN AND CLOSED POSITIONS FOR CONTROLLING LIQUID FLOW THERETHROUGH, SAID VALVE MEMBERS HAVING A FIRST SET OF FLOW REGULATING POSITIONS CLOSING THE PORTIONS OF SAID LIQUID LINE BETWEEN SAID PASSAGES AGAINST LIQUID FLOW THERETHROUGH WHEN BOTH OF SAID PASSAGES ARE OPEN TO DISPOSE SAID RECEIVER IN SERIES FLOW RELATION BETWEEN SAID CONDENSER AND EXPANSION DEVICE DURING OCCURRENCE OF A RELATIVELY HIGHER RANGE OF AMBIENT TEMPERATURES, AND SAID VALVE MEMBERS ALSO HAVING A SECOND SET OF FLOW REGULATING POSITIONS CLOSING ONE OF SAID PASSAGES AND OPENING SAID LIQUID LINE BETWEEN PASSAGES WHEREIN THE OTHER PASSAGE FORMS A SINGLE LINE CONNECTION BETWEEN THE RECEIVER AND LIQUID LINE FOR PASSAGE OF LIQUID REFRIGERANT THEREBETWEEN IN EITHER DIRECTION TO PERMIT LIQUID REFRIGERANT TO BACK UP IN SAID CONDENSER AND PARTIALLY FLOOD THE SAME UPON ENERGIZATION OF SAID HEATER MEANS AND INSURE MAINTENANCE OF CONDENSING PRESSURE ABOVE A SELECTED MINIMUM DURING OCCURRENCE OF LOW AMBIENT TEMPERATURE CONDITIONS IN A RANGE WHICH WOULD DEPRESS CONDENSING PRESSURE BELOW THE SELECTED MINIMUM.