DEVICE AND METHOD FOR COOLING AND/OR LOW-TEMPERATURE LIQUEFACTION

摘要

The invention relates to a device for cooling and/or liquefying, at a low-temperature, a working fluid containing helium or consisting of pure helium. The device includes a working circuit provided with a compressor station and a cold box. The compressor station includes one or more compression stages, each using one or more compressors that include a compressor wheel rigidly connected to an axle that is rotatably mounted on bearings. The axle of each compressor is rotated by an output shaft of a motor via a gear mechanism placed in a mechanical housing including lubricating oil. Said device is characterized in that the inner space of the mechanical housing contains a gaseous atmosphere consisting of a gaseous mixture having a mean molar mass that smaller than the molar mass of the air.