Refrigerant flow control means

Claim 1

APPARATUS FOR MAINTAINING A CHAMBER AT A PREDETERMINED LOW TEMPERATURE WITH A MINIMUM OF VARIATIONS IN SUCH TEMPERATURE, COMPRISING: A FIRST INSULATED HOUSING FORMING THE CHAMBER; A SECOND INSULATED HOUSING ENCLOSING THE FIRST HOUSING WITH SPACE BETWEEN THE FIRST AND SECOND HOUSINGS SURROUNDING THE FIRST HOUSING; A CONDUIT MEANS FORMED AS A COIL HAVING MULTIPLE TURNS AND DISPOSED TO SURROUND THE FIRST HOUSING IN CLOSE PROXIMITY THERETO, SAID FINAL TURN OF SAID COIL DISPOSED TO HAVE TWO SERIES OF GAS EXHAUST HOLES ON OPPOSITE SIDES OF THE FIRST HOUSING WITH ALL OF SAID HOLES IN EACH SERIES BEING ORIENTED TO DISPERSE A SPRAY OF COOLANT IN THE SAME CIRCUMFERENTIAL DIRECTION; A SUPPLY OF COOLANT; VALVE MEANS CONNECTING THE COOLANT SUPPLY TO SAID CONDUIT MEANS; A TEMPERATURE SENSOR POSITONED IN SAID SPACE IN PROXIMITY WITH SAID CONDUIT MEANS; AND CONTROL MEANS CONNECTED TO SAID VALVE MEANS AND SAID SENSOR FOR STOPPING THE FLOW OF THE COOLANT INTO SAID CONDUIT MEANS AT A FIRST FLOW TEMPERATURE BELOW SAID PREDETERMINED TEMPERATURE AND STARTING THE FLOW OF COOLANT INTO SAID CONDUIT MEANS AT A SECOND, HIGHER, LOW TEMPERATURE BELOW SAID PRE-DETERMINED TEMPERATURE.