Accession Number : AD0625120

Title :   PRESSURE BURSTS IN BAKEABLE ULTRA-HIGH VACUUM VALVES DURING OPENING AND CLOSING.

Descriptive Note : Technical rept.,

Corporate Author : ARMY ELECTRONICS COMMAND FORT MONMOUTH N J

Personal Author(s) : Buser,Rudolf G. ; Sullivan,John J.

Report Date : SEP 1965

Pagination or Media Count : 22

Abstract : The pressure increase delta p produced by opening and closing bakeable ultrahigh vacuum valves of different commercial sources has been determined using mass spectrometric and other standard techniques. Typical results show: (1) Dependence of delta p on geometry and material of bellow seat and gasket and their previous treatment. (2) Delta p (Bellows; gasket closing, opening) approaches after initial operation a constant value. (3) Delta p (closing) < Delta p (opening for the gasket). (4) Delta p (closing) same order of magnitude as Delta p (opening for the bellows). (5) Pressure bursts correspond in most cases to an equivalent increase of the partial pressure of H2. (6) Delta p (bellows) shows weak dependence on background pressure, delta p (gasket) is pressure independent. Results are applied to a mass spectrometric sampling method. It is shown that the introduction of bakeable valves into the system may be the limiting factor of the experiment, and otherwise ideal conditions will permit measurement of impurity ratios, e.g. for H2 in He in the order of 1/10 to the 7th power at best. (Author)

Descriptors :   (*HIGH VACUUM VALVES, OPERATION), VACUUM, PRESSURE, MEASUREMENT, IMPURITIES, SPECTRUM ANALYZERS, GASES

Subject Categories : Pumps, Filters, Pipes, Tubing, Fittings & Vlvs
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE