Abstract

A cryogenic refrigerator uses a mixture of helium-3 and helium-4. Gaseous helium is pumped from a reservoir containing a liquid mixture of helium-3 and helium-4 to cause cooling and a phase separation into an upper helium-3 rich phase which floats at the top for further evaporation and a lower dilute phase below the helium-3 rich phase. This separation enables operation at temperatures typical of a helium-3 refrigerator while initial liquefaction of the mixture is easier than liquefaction of pure helium-3 and can use a smaller amount of helium-3. Embodiments of the refrigerator can provide continuous cooling.

IPC Classes  ?

• F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
• F25B 9/02 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using Joule-Thompson effectCompression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using vortex effect
• F25B 9/12 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using 3He-4He dilution
• F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle

IPC Classes  ?

• F25B 9/12 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using 3He-4He dilution
• F25B 15/10 - Sorption machines, plants or systems, operating continuously, e.g. absorption type with inert gas

Abstract

A cryogenic refrigerator uses a mixture of helium-3 and helium-4. Gaseous helium is pumped from a reservoir containing a liquid mixture of helium-3 and helium-4 to cause cooling and a phase separation into an upper helium-3 rich phase which floats at the top for further evaporation and a lower dilute phase below the helium-3 rich phase. This separation enables operation at temperatures typical of a helium-3 refrigerator while initial liquefaction of the mixture is easier than liquefaction of pure helium-3 and can use a smaller amount of helium-3. Embodiments of the refrigerator can provide continuous cooling.

IPC Classes  ?

• F25B 9/12 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using 3He-4He dilution
• F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle