| 摘要 |
PCT No. PCT/EP94/01637 Sec. 371 Date Nov. 20, 1995 Sec. 102(e) Date Nov. 20, 1995 PCT Filed May 13, 1994 PCT Pub. No. WO94/28314 PCT Pub. Date Dec. 8, 1994The present invention relates to a pumping device which is suitable for pumping mixtures of gases at cryogenic temperatures which is a combination of a cryogenic diffusion pump and a thermal gradient barrier diffusion pump. Specifically, the pumping device comprises an elongate body of material capable of withstanding cryogenic temperatures and of sustaining an axial temperature gradient in use. The elongate body has an inlet for the gas mixture and an outlet for one or more gases to be pumped, wherein the outlet is filled with a porous barrier through which gases must pass to exit the device. The porous body has a heating means disposed at its outlet side.
|
