Controls for refrigeration systems having air cooled condensers

Claim 1

IN A REFRIGERATION SYSTEM HAVING A COMPRESSOR, AN AIR COOLED CONDENSER, AN EXPANSION DEVICE, AND AN EVAPORATOR CONNECTED IN SERIES IN THE ORDER NAMED IN A REFRIGERATION CIRCUIT, THE COMBINATION OF A LIQUID PUMP CONNECTED IN SAID CIRCUIT BETWEEN SAID CONDENSER AND SAID DEVICE FOR PUMPING LIQUID FROM SAID CONDENSER TO SAID DEVICE, MEANS INCLUDING A CHECK VALVE FORMING A BY-PASS AROUND SAID PUMP FOR FLOWING LIQUID FROM SAID CONDENSER TO SAID DEVICE WHEN SAID PUMP IS NOT OPERATING, A GAS TURBINE CONNECTED IN SAID CIRCUIT BETWEEN SAID COMPRESSOR AND SAID CONDENSER AND CONNECTED TO SAID PUMP TO DRIVE SAID PUMP, MEANS FORMING A SECOND BY-PASS AROUND SAID TURBINE, AND MEANS INCLUDED IN SAID SECOND BY-PASS AND INCLUDING MEANS RESPONSIVE WHEN SAID CHECK VALVE IS CLOSED, TO THE DIFFERENCE BETWEEN THE SUCTION PRESSURE AT SAID COMPRESSOR AND THE LIQUID PRESSURE AT SAID EXPANSION DEVICE FOR INCREASING THE FLOW OF GAS THROUGH SAID SECOND BY-PASS WHEN SAID DIFFERENCE EXCEEDS A PREDETERMINED MINIMUM AND FOR DECREASING THE FLOW OF GAS THROUGH SAID SECOND BY-PASS WHEN SAID DIFFERENCE IS AT OR IS LESS THAN SAID MINIMUM.