Abstract: Method of reliquefying gaseous helium produced when transferring liquid helium from a donor container (R1) to a receiver container (R2), characterized in that a stream of gaseous helium is bled off from a point in a compression unit (10) intended for charging with gaseous helium under pressure, this stream of gaseous helium is cooled by heat exchange with the gaseous helium intended for the compression unit (10) and the compressed gaseous helium thus cooled is expanded in order to obtain reliquefied helium.

Abstract: A process and installation for the cryogenic purification of impure hydrogen, of the type in which impure hydrogen is cooled under a low pressure PO to a temperature sufficiently low to condense a predetermined proportion of the impurities, by heat exchange in a thermal heat exchange line (3) with purified hydrogen and with a residual fraction containing the expanded preliminarily condensed impurities (in 11, 12) to a low pressure P1. The remaining cold is supplied by the expansion of purified hydrogen in a turbine (8) with gas bearings and the expanded hydrogen is added to the light impurities expanded at the cold end of the heat exchange line. The turbine (8) is supplied with the gas leaving its bearings (17), after cooling of hydrogen at the labyrinthine seal (18) of the turbine is withdrawn under a pressure slightly less than the interstitial pressure Pi which prevails between the rotor (14) and the stator (16) of this turbine.

Abstract: The present invention relates to internal and shaft outlet seals of a pump. On both sides of a paddle-wheel are arranged a pair of coaxial discs (22-23) and (24-25), the face of one disc being smooth and the face of the other disc having spiral grooves, one of the discs of each pair being interlocked in rotation with wheel 5, whereby the liquid between two discs is subjected to a pressure increase radially outwardly compensating at least for the pressure increase due to pumping by wheel 5.