Accession Number : AD0002008


Title :   EXPERIMENTS WITH A DIFFERENTIAL PIRANI GAUGE LEAK DETECTOR


Corporate Author : ATOMIC ENERGY RESEARCH ESTABLISHMENT HARWELL (UNITED KINGDOM)


Personal Author(s) : TURNBULL, A H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/002008.pdf


Report Date : Mar 1950


Pagination or Media Count : 15


Abstract : A differential leak detector was developed in which 2 matched Pirani gages having their filaments connected in adjacent arms of a balanced Wheatstone bridge were connected to the same point in a vacuum system. A lime soda trap was placed between the vacuum system and 1 gage to absorb the COsub2 which was used to probe the leak. The COsub2 could make its way only into the untrapped gage to cause a differential change in the indication of the 2 gages. With the detector located on the backing side of a diffusion pump where the average pressure was 15 micro Hg, the noise level of pressure fluctuations registered by the galvanometer in the detector control circuit was 7 times less than that registered by a single Pirani gage. The minimum air pressure change detected by the differential arrangement was 10 to the -5th power mm Hg. With the optimum leak-hunting conditions employed, this value corresponded to a leak on the high- vacuum side of about 10 to the -3rd power lusec (1 lusec = the leak causing a pressure rise of 1 micro Hg/sec in an isolated volume of 1 liter).


Descriptors :   *LEAK DETECTORS , LEVEL(QUANTITY) , FILAMENTS , DIFFUSION , UNITED KINGDOM , PUMPS , AIR PRESSURE , GALVANOMETERS , VACUUM APPARATUS , NOISE


Subject Categories : Test Facilities, Equipment and Methods


Distribution Statement : APPROVED FOR PUBLIC RELEASE