Refrigeration purge control

Claim 1

IN A CLOSED REFRIGERATION SYSTEM CIRCULATING A VOLATILE REFRIGERANT AND HAVING A MAIN COMPRESSOR, A MAIN CONDENSER INCLUDING A COOLING COIL AND HAVING AN UPPER VAPOR HOLDING PORTION CONNECTED TO THE MAIN COMPRESSOR DISCHARGE RECEIVING VAPORIZED REFRIGERANT AND NON-CONDENSABLE GASES, AND HAVING A HOT WELL IN THE CONDENSER LOWER PORTION HOLDING SATURATED REFRIGERANT CONDENSATE AT CONDENSER PRESSURE: (A) A PURGE MECHANISM CONNECTED TO AND OPERABLE WITH SAID REFRIGERATION SYSTEM TO REMOVE NON-CONDENSABLE GASES THEREFROM, (B) SAID PURGE MECHANISM INCLUDING A MOTOR DRIVEN AUXILIARY COMPRESSOR HAVING AN INLET COMMUNICATED WITH THE REFRIGERATION SYSTEM TO RECEIVE A FLOW OF BOTH VAPORIZED REFRIGERANT AND NON-CONDENSABLE VAPORS, (C) A REFRIGERANT CONDENSATE COLLECTOR POSITIONED IN THE MAIN CONDENSER VAPOR HOLDING PORTION, HOLDING A POOL OF SAID CONDENSATE UNDER CONDENSER PRESSURE, (D) CONTROL MEANS CONNECTED TO THE SYSTEM TO REGULATE OPERATION OF THE AUXILIARY COMPRESSOR MOTOR AND ACTIVATE SAID PURGE MECHANISM IN RESPONSE TO THE VOLUME OF NON-CONDENSABLE VAPORS CONTAINED IN THE REFRIGERATION SYSTEM IN EXCESS OF A PREDETERMINED AMOUNT, (E) SAID CONTROL MEANS INCLUDING: (1) SENSING MEANS POSITIONED IN THE CONDENSATE COLLECTOR IN CONTACT WITH THE CONDENSATE POOL THEREIN, (2) SAID SENSING MEANS BEING CONNECTED TO THE PURGE MECHANISM AUXILIARY COMPRESSOR MOTOR TO REGULATE OPERATION THEREOF IN RESPONSE TO A VARIATION IN PRESSURE IN THE MAIN CONDENSER VAPOR HOLDING PORTION.