Process for pumping gaseous helium at cryogenic temperatures by a positive displacement pump
AssigneeCommissariat a l'Energie Atomique
InventorGerard Claudet
Life of this patent
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Abstract
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.
Claims13
Process for pumping evaporated gaseous helium at cryogenic temperatures, characterized by the steps of selecting a positive displacement pump comprising a spiral fixed part (37, 38, 39, 40) and a spiral mobile part (35, 36), the fixed part and the mobile part being constructed with intermediate clearances avoiding any friction and provided with a pump cooling device (41, 42);
- cooling the spiral parts with the cooling device;
- rotating the spiral mobile part with respect to the fixed part in order to define therewith a delivery volume;
- attracting the helium into the delivery volume;
- compressing the helium by a decrease of said volume;
- and subsequently passing the helium out of the pump.
A process for pumping evaporated gaseous helium at cryogenic temperatures, comprising the steps of selecting a scroll type pump comprising a stationary spiral part and a mobile spiral part used for said pumping, the stationary spiral part being separated from the mobile spiral part with clearances;
- moving the mobile spiral part along a circular trajectory with respect to the stationary spiral part so as to displace said gaseous helium;
- and cooling said spiral parts.
A cryogenic gaseous helium pump comprising:
- a spiral fixed part;
- a spiral mobile part, the fixed part and the mobile part being constructed with intermediate clearances avoiding any friction, the mobile part being rotatable with respect to the fixed part to define therewith a delivery volume into which the helium is attracted and compressed by a decrease of said volume before the helium is passed out of the pump;
- and
- a pump cooling device disposed on the fixed part.
Dependencies are inferred from the claim text.