(19)
(11) EP 0 208 526 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
04.10.1989 Bulletin 1989/40

(43) Date of publication A2:
14.01.1987 Bulletin 1987/03

(21) Application number: 86305218.9

(22) Date of filing: 07.07.1986
(51) International Patent Classification (IPC)4: F25B 25/00, F25B 41/00, F25B 1/00
(84) Designated Contracting States:
BE DE FR IT NL SE

(30) Priority: 10.07.1985 GB 8517445

(71) Applicant: The BOC Group plc
Windlesham Surrey GU20 6HJ (GB)

(72) Inventor:
  • Miller, Jeremy Paul
    Near Farringdon, Oxfordshire (GB)

(74) Representative: Wickham, Michael et al
c/o Patent and Trademark Department The BOC Group plc Chertsey Road
Windlesham Surrey GU20 6HJ
Windlesham Surrey GU20 6HJ (GB)


(56) References cited: : 
   
       


    (54) Refrigeration method and apparatus


    (57) In a mechanical refrigeration apparatus of the vapour compression kind, comprising a compressor 2, condenser 4, expansion valve 6, and evaporator 8, a sub-cooler 12 is employed to reduce the temperature of the condensed refrigerant to a value at which at least 90% by volume and preferably all of it remains in the liquid phase on passagethrough the expansion valve 6. The sub-cooler 12 is cooled by means of a supply of liquid nitrogen from vessel 14. Alternatively, liquid nitrogen is evaporated in a circulating heat exchange atmosphere in the sub-cooler 12. Increased heat load in chamber 10 may thus be met without there necessarily being any increase in the evaporating temperature and pressure.






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