无油泵对检漏系统有效最小可检漏率影响研究  

Negative Impact of Oil-Free Vacuum Pump on Lowest Detectable Rate of Helium Mass Spectrometer Leak Detector

作　　者：孟冬辉[1] 孙立臣[1] 邵容平[1] 闫荣鑫[1] 张春元[1] 陈金明[1] 张海峰[1] 喻新发[1] 王健[1] 

机构地区：[1]北京卫星环境工程研究所,北京100094

出　　处：《真空科学与技术学报》2016年第8期941-944,共4页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金"航天先进制造技术研究"联合基金资助项目(项目编号:U1537109)

摘　　要：真空检漏技术广泛应用于航天、航空、核工业等军工行业的密封产品测试,近些年,无油真空泵逐步代替了油封式机械泵作为检漏系统的前级泵。无油泵作为前级泵具有清洁无油的优点,但实践中经常出现检漏系统本底异常升高、检漏系统有效最小可检漏率与理论分析结果相差较大的情况。本文从检漏系统有效最小可检漏率的影响因素入手,结合容积式真空泵工作原理,分析了无油泵对检漏系统有效最小可检漏率的影响原因,并进行了实验验证,给出了改进建议。With thegrowing popularity ofoil-free roughing pump,particularly in aerospace,aviation and nuclear industries because of its cleanliness,two problems surfaced when it comes to leak detection with heliummass spectrometer leak-detector; one is the high background He-concentration,the other is the large discrepancy between the theoretically calculated and experimentally measured effective minimum detectable leakage rates. Analysis of the gas-flow from the turbo molecular pump to the mass spectrometer and oil-free roughing pump indicates that the backflow of atmospheric air through the roughing pump results in the problems. Two possible solutions were proposed： one is to replace the dry screw pump with Roots pumps because of its lower pressure; the other is to temporarily close the inlet-valve of dry screw pump in leak detection of a small volume with detectors working at high pumping-speed. Test results show that the solutions considerably increase the leak detection sensitivity.

关 键 词：检漏 氦质谱 最小可检漏率 无油真空泵 

分 类 号：TB774[一般工业技术—真空技术]