Patent ID: 7165422

Claim:
A device for liquefaction of a gas, the device comprising: a thermally insulated region in which the gas is liquefied and collected, a gas supply system comprising a first section outside the thermally insulated region and a second section within the thermally insulated region, wherein the first section provides a purified stream of gas to a gas supply line in the second section, a cryogenic refrigerator comprising a warm section outside the thermally insulated region and a cold section inside the thermally insulated region, wherein the cold section is thermally coupled to the second section of the gas supply system to cool the purified stream of gas, a dispensing line comprising an input end within the thermally insulated region and an output end outside the thermally insulated region, wherein: the first section of the gas supply system comprises a compressor to compress the gas so that the purified stream of gas has a high pressure above atmospheric pressure; the cold section of the cryogenic refrigerator has a minimum temperature above a boiling point of the gas at atmospheric pressure and below a boiling point of the gas at the high pressure, the second section of the gas supply system comprises a flow restrictor where the pressure drops from the high pressure to atmospheric pressure and a portion of the purified stream of gas evaporates, cooling a fraction of the purified stream of gas to the boiling point of the gas at atmospheric pressure.