DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click
HERE to register or log in.
Accession Number:
AD0002008
Title:
EXPERIMENTS WITH A DIFFERENTIAL PIRANI GAUGE LEAK DETECTOR
Descriptive Note:
Corporate Author:
ATOMIC ENERGY RESEARCH ESTABLISHMENT HARWELL (UNITED KINGDOM)
Report Date:
1950-03-01
Pagination or Media Count:
15.0
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 Hgsec in an isolated volume of 1 liter.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE