Leak tester

Chlorine excitation was obtained by a corona discharge on platinum wire points at 40 kv., 2 ma., and 4-5 Me. from the tesla coil output of a vacuum system leak tester. According to Steacie (3) more than 40% atomic chlorine... 

D. Leak Detection Using Helium or Halogen Leak Detectors. Commercial leak testers have high sensitivity and are very useful with metal vacuum systems. Only two common types, one based on halogenated compounds and one based on helium, will be covered here. 

The halogen leak tester is widely used in refrigeration applications, but it is sufficiently sensitive for many types of chemical vacuum systems. The apparatus is filled with a halogenated hydrocarbon and the probe of the tester is passed over the suspected area. The gas that is collected by the probe is passed over a hot platinum wire with the resulting formation of positive ions which are collected and measured with a microammeter. 

Passage of CF3OF over a cold-glow electrical discharge (from a vacuum "leak tester" of the Tesla-coil variety) immersed in a metallic vessel caused decomposition into COFj (0.38 mol per mol of CF3OF), Fj, CF, CO3, Oj and fluorocarbons [1649]. 

The pressure measurements should always be done by capacitance manometers (CAs) and not by thermal conductive gauges. TM depend on the gas mixture (water vapor and permanent gases) and are not reproducible enough for BTM measurements details are given on pp 327, 328 in [2]. For leak testing no special equipment specifications are required. The leak rate for the chamber, e.g., <1 x 10 mbarL/s, and for the condenser, e.g., <1 X 10 mbarL/s, should be specified since it might be helpful to measure the chamber and condenser separately. The maximum tolerable leak rate in the two examples is <1 x 10 mbarL/s, if the DR data at 0.1%/h should have an error <10%. If a helium leak tester is not available in production, it should be specified for quotation. 

Hot Plate Welders, Ultrasonic Welders, Spin Welders, Vibration Welders, Thermo Stakers, Leak Testers, supplier marketing literature (GC1095), Forward Technol. Ind. Inc., 1995. 

Tlu ability of litiuid metals and liquid salts to leak through extremely email oiiciiings has made the use of helium mass-spectrometer leak testers a sjicriticd test step. Halogen leak testers should never be used because of the absorbi d halogen which remains in the surfaces after the tests. 

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