Removable refrigerator for maintaining liquefied gas inventory

摘要

A cryostat for maintaining an inventory of a liquefied cryogen including a vacuum jacketed reservoir (Dewar) containing heat shields in the vacuum jacket, the heat shields cooled to different temperatures and a cryogen recondenser cooled by a cryogenic refrigerator. Included in the cryostat is an access passage to place objects in the cryogen and to support the refrigerator, the access passage including means to remove the refrigerator without opening the liquid cryogen to ambient atmosphere.