| abstract |
The invention relates to an apparatus for producing liquid nitrogen, which has a cold chamber (2) of an extremely low temperature refrigeration machine (3), protruding into a refrigerant storage container (1) composed of 'an insulating container, with respect to an opening formed at the upper end of the refrigerant storage container (1), the latter being supplied with nitrogen in the gas phase separated by means of an air separation device ( 4), so that a refrigerant gas is liquefied by the cold supplied by said cold chamber (2). - Advantageously, a pressure detector instrument (21) is placed in a product container (20) of said air separation device (4), and a negative pressure sensor (16) is placed in said refrigerant storage container (1). |