Commissariat a L'energie Atomique

Air Liquid

Gerard Claudet

Marcel Locatelli

Serge Reale

Pierre Roubeau

Bernard Dewanckel

Gilbert Bon Mardion

Alain Ravex

Jacques Verdier

Albert Lacaze

Gilbert Bon-Mardion

The apparatus for the expansion of fluid in the gaseous or liquid state or in double phase is characterized in that it has an expansion compartment comprising:

Temperature lowering apparatus using cryogenic expansion with the aid of

Application of a positive displacement pump to the pumping of helium at very low temperatures. Positive displacement pumps, formed from mobile components (35, 36), which deliver gas volumes to pumping chambers, have the advantage of operating under satisfactory conditions for significant temperature, pressure and gas flow rate variations. They are therefore preferred as compared with the hitherto used centrifugal pumps and have means enabling them to operate at very low temperatures.

Process for pumping gaseous helium at cryogenic temperatures by a

It comprises a first cylinder (102), a displacement piston (104) sliding in the first cylinder (102), a conduit in which a thermal regenerator is included, a second cylinder (202), a second displacement piston (204) sliding in the second cylinder (202), means for displacing the first cylinder and the second cylinder in phase relation. A gas bearing (104a) is provided at the hot end of the first piston (104) and a gas bearing (104b) is provided at the intermediate temperature end of the first piston. A gas bearing (204b) is also provided at the intermediate temperature end of the second piston (204) and a gas bearing (204a) is provided at the cold end of the second piston (204).

Refrigerator, more particularly with Vuilleumier cycle, comprising

The device comprises in the tank above the liquid:

Device for automatically regulating the superfluid helium level in a tank

The invention relates to a refrigerating or heat pumping process, as well as to an apparatus for performing this process. The apparatus comprises a toroidal cryostat, provided with first and second pipes for supplying fluid at temperature T.sub.1 from a heat source and a pipe for discharging this fluid, a paramagnetic substance support rotating in the cryostat, means for inducing a magnetic field in the cryostat, a fourth pipe for supplying fluid and a fifth pipe for discharging fluid at temperature T.sub.2 relative to a cold source. The magnetic field applied makes it possible, during the rotation of the support, to lower the temperature of the cold source and increase the temperature of the hot source. Application to refrigeration and heat pumping.

Refrigerating or heat pumping process and apparatus

A bath of helium-4 is cooled to a temperature below the .lambda. point so as to convert the lower portion of the bath to a superfluid-helium zone. A narrow stream between a top and a bottom portion of the zone is subjected to a critical heat flux corresponding to a temperature gradient by cooling the bath in the bottom portion of the superfluid-helium zone, the temperatures thus attainable being considerably lower than the .lambda. transition point.

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La Tronche, France

Gerard Claudet