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1. 发明专利

CA1310765C COUNTERFLOW LEAK DETECTOR WITH HIGH AND LOW SENSITIVITY OPERATING MODES 未知
公开(公告)号：CA1310765C
公开(公告)日：1992-11-24
申请号：CA585585
申请日：1988-12-09
申请人： VARIAN ASSOCIATES
发明人： LANDFORS ARTHUR A
IPC分类号： F04B37/00 , F04B37/02 , F04F9/00 , G01M3/20 , G01N27/62 , H01J49/04
摘要： COUNTERFLOW LEAK DETECTOR WITH HIGH AND LOW SENSITIVITY OPERATING MODES A counterflow helium mass spectrometer leak detector in which a helium sample passes in a reverse direction through a diffusion pump to a mass spectrometer for measurement. The diffusion pump includes a conventional foreline and a second foreline provided with an ejector stage. A test sample is coupled from a test port through a bypass valve to the conventional foreline in a high sensitivity mode and is coupled to the second foreline in a low sensitivity mode. In the low sensitivity mode, the bypass valve is closed. An apertured control plate in the diffusion pump controls the relative reverse rates of diffusion from each foreline to the diffusion pump inlet by controlling the rates of vapor flow to annular pumping stages and to the ejector stage. The ejector stage includes a nozzle for directing a stream of vapor into the second foreline so as to inhibit flow of helium into the diffusion pump and establish a lower reverse diffusion rate at the second foreline. The disclosed configuration permits measurement of a large range of leak rates.

2. 发明授权

US3876337A High vacuum pumping systems 失效
标题翻译：高真空泵送系统
公开(公告)号：US3876337A
公开(公告)日：1975-04-08
申请号：US34141973
申请日：1973-03-15
申请人： VARIAN ASSOCIATES
发明人： LANDFORS ARTHUR A
IPC分类号： F04F9/06 , F04F9/00 , F16L23/00
CPC分类号： F04F9/06
摘要： A trap assembly in a high vacuum system for intercepting back streaming liquid or suspended liquid molecules from a diffusion pump to prevent contamination of the working high vacuum chamber is disclosed. The trap assembly includes a tubular member defining a passageway between the hollow inlet means of the chamber and the inlet orifice of the pump, and a restriction means across the passageway. The tubular member includes an envelope wall physically forming the passageway in the region of the restriction means, and fastener means extending within said passageway inside the confines of said wall to interconnect said wall with said pump and with said hollow inlet means of said chamber to gain maximum internal area for a given overall outer dimensional extent of the tubular member. The fastener means includes mating flanges and a plurality of bolts around the flanges. The bolts may be sealed by sleeves that also bear at least a portion of the tightening load of the bolts and thereby assist the envelope wall in this function. The restriction means in the passageway includes a plate positioned at an angle to allow draining action of condensed liquid, and a cooling tube is effective to cool the plate and the sleeves to increase condensation. The sleeves are cylindrical and only slightly larger than the bolts to provide minimum volume displacement. The radius of the passageway has been increasaed by approximately 50 percent over prior art devices, with a consequent cross-sectional area increase in the full region of the passageway of substantially 100 percent. The retained speed of the pump is increased over the prior art capability by approximately 50 percent.

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