Truck refrigeration system

Claim 1

THE COMBINATION IN A TEMPERATURE CONDITIONING OR REFRIGERATING SYSTEM OF MEANS PROVIDING A FIRST REFRIGERATING CIRCUIT, A VESSEL ADAPTED TO CONTAIN A QUANTITY OF A LOW MELTING POINT MEDIUM, AND MEANS PROVIDING A SECOND REFRIGERATING CIRCUIT, SAID FIRST CIRCUIT INCLUDING A REFRIGERANT CIRCULATING EVAPORATOR COIL DISPOSED IN SAID VESSEL TO BE IMMERSED IN SAID MEDIUM TO REFRIGERATE THE LATTER BY ABSORBING HEAT THEREFROM, SAID SECOND CIRCUIT INCLUDING A REFRIGERANT CIRCULATING CONDENSER COIL SIMILARLY DISPOSED IN SAID VESSEL TO BE REFRIGERATED BY SAID MEDIUM UPON ABSORPTION INTO THE LATTER OF HEAT FROM THE CONDENSER COIL, A REFRIGERANT CIRCULATING EVAPORATOR COIL OF SAID SECOND CIRCUIT DISPOSED EXTERNALLY OF SAID VESSEL, MEANS PLACING SAID CONDENSER AND EVAPORATOR COILS OF SAID SECOND CIRCUIT IN COMMUNICATION WITH ONE ANOTHER, THE FLOW OF REFRIGERANT IN SAID COILS OF SAID SECOND CIRCUIT, OTHER THAN AS AFFECTED BY TEMPERATURE CHANGE, BEING UNDER THERMAL DRAFT AT A PREDETERMINED, SUBSTANTIALLY CONSTANT PRESSURE, AND MEANS TO CIRCULATE AIR TO BE REFRIGERATED PAST THE EVAPORATOR COIL OF SAID SECOND CIRCUIT, SAID AIR CIRCULATING MEANS COMPRISING A PAIR OF FANS HAVING ADJACENT SEPARATE DISCHARGES AND DRIVEN RESPECTIVELY BY SEPARATE SOURCES, EACH OF SAID FANS HAVING CHECK VALVE MEANS AT THE DISCHARGE THEREOF TO PREVENT CIRCULATION BY EITHER ONE THEREOF THROUGH THE OTHER AND NOT PAST THE EVAPORATOR COIL OF SAID SECOND CIRCUIT.