Abstract: The invention relates to an installation and a process for production of a cryogenic fluid, in particular of liquefied hydrogen, comprising, positioned in at least one cold box, a set of heat exchangers in thermal exchange with the circuit for hydrogen to be cooled, the installation comprising a device for pre-cooling, which is configured to pre-cool the circuit for gas to be cooled to a first determined temperature, and a device for cryogenic cooling which is configured to cool the circuit for gas to be cooled to a second determined temperature, lower than the first temperature, the cycle gas cooling unit and/or the cycle gas heating unit comprise(s) one or more first cycle heat exchangers distinct from the first part of the pre-cooling heat exchangers of the circuit for the gas to be cooled, these first cycle heat exchangers also being cooled by thermal exchange with the pre-cooling fluid circuit of the pre-cooling device.

Abstract: In a torque transmitting coupling between a cylindrical shaft and a female member having a bore to receive the shaft, the shaft has a secant face and the female member has a connecting bolt bore which intersects the shaft bore and faces the secant face of the shaft. A connecting bolt in the bolt bore of the female member has a secant face which tightly engages the secant face of the shaft. In one embodiment, the shaft axis, secant faces of the shaft and bolt and the bolt bore are all parallel. In another embodiment the axis of the bolt bore is inclined at a small angle to the secant face, the bolt being of wedge form. A screw extending through a hole in the female member and screwed into a tapped hole in the bolt is rotatable to move the bolt axially and thereby wedge the secant face of the bolt against the secant face of the shaft. The secant faces of the shaft and bolt may have intermeshing longitudinally extending serrations.