Cryogenic joule-thomson helium liquefier with cascade helium and nitrogen refrigeration circuits

Claim 1

A CRYOGENIC LIQUEFIER, COMPRISING IN COMBINATION (A) AN ACTIVE REFRIGERATOR IN WHICH REFRIGERATION IS DEVELOPED BY INITIALLY COOLING A HIGH-PRESSURE FLUID AND THEN EXPANDING AND FURTHER COOLING IT, AND INCLUDING FIRST, SECOND AND THIRD HEAT STATIONS ADAPTED TO EFFECT OUT-OF-CONTACT HEAT EXCHANGE WITH SAID FLUID IN SAID REFRIGERATOR; (B) A JOULE-THOMSON LOOP COMPRISED OF FIRST AND SECOND PRIMARY OUT-OF-CONTACT HEAT EXCHANGERS ADAPTED TO EFFECT HEAT EXCHANGE BETWEEN INCOMING HIGH-PRESSURE FLUID AND DISCHARGING LOW-PRESSURE FLUID, AND FIRST AND SECOND SECONDARY OUT-OF-CONTACT HEAT EXCHANGERS ADAPTED TO EFFECT HEAT EXCHANGE BETWEEN SAID HIGHPRESSURE FLUID AND SAID SECOND AND THIRD HEAT STATIONS OF SAID ACTIVE REFRIGERATOR; (C) A TRANSFER TUBE IN FLUID COMMUNICATION WITH SAID SECOND PRIMARY HEAT EXCHANGER, CHARACTERIZED BY HAVING AN INNER HIGH-PRESSURE PASSAGE, AN INTERMEDIATE LOW-PRESSURE CHANNEL AND AN OUTER INSULATION, AND EXTENDING EXTERNALLY OF SAID LIQUEFIER; (D) A JOULE-THOMSON EXPANSION VALVE TERMINATING SAID TRANFER TUBE ADAPTED TO EXPAND AND LIQUEFY SAID HIGHPRESSURE FLUID AND TO RETURN SAID LOW-PRESSURE FLUID IN SAID JOULE-THOMSON LOOP; (E) A PURIFIER ADAPTED TO REMOVE CONTAMINANTS FROM SAID FLUID PRIOR TO INTRODUCTION INTO SAID ACTIVE REFRIGERATOR AND SAID JOULE-THOMSON LOOP AND COMPRISING MEANS FOR REMOVING SAID CONTAMINANTS THROUGH SOLIDFICATION AND ABSORPTION; (F) RADIATION SHIELDING MEANS SURROUNDING THE COLDER END OF SAID ACTIVE REFRIGERATOR, SAID JOULE-THOMSON LOOP, AND SAID PURIFIER; (G) HEAT EXCHANGE MEANS ADAPTED TO CIRCULATE AN EXTERNALLY SUPPLIED REFRIGERANT IN OUT-OF-CONTACT HEAT EXCHANGE WITH SAID FIRST HEAT STATION OF SAID ACTIVE REFRIGERATOR, SAID RADIATION SHIELDING MEANS, SAID PURIFIER, AND SAID FIRST PRIMARY HEAT EXCHANGER OF SAID JOULE-THOMSON LOOP; AND (H) HOUSING MEANS ENCLOSING SAID ACTIVE REFRIGERATOR, SAID JOULE-THOMSON LOOP, A PORTION OF SAID TRANSFER TUBE, AND SAID PURIFIER.