Title:
EXTRA-HIGH VACUUM MEASURING APPARATUS
Document Type and Number:
Japanese Patent JPS63145935
Kind Code:
A
Abstract:
PURPOSE:To measure pressure in a vacuum atmosphere regardless of the composition ratio of a gas contained therein, by connecting a vacuum chamber to a gas inlet of a compressor with the compression ratio confirmed for various gases and a partial pressure indicator with the sensitivity coefficient confirmed for various gases to a gas outlet of the compressor. CONSTITUTION:A partial pressure PB(i) is determined at a gas outlet 16 of a compressor 14 with respect to various gases contained in a vacuum atmosphere from a sensitivity coefficient theta(i) and a reading U(i) of a partial pressure indicator 17. A partial pressure at a gas inlet 15 of the compressor 14, namely, a partial pressure PA(i) in the vacuum atmosphere can be determined from the partial pressure PB(i) and a compression ratio Q(i) of the compressor 14. Moreover, an arithmetic unit 18 determines pressure in the vacuum atmosphere, the total of partial pressures PA(i) of various gases (i) obtained for all available gases. The total pressure thus obtained provides a true pressure regardless of the type and composition ratio of gases composing the vacuum atmosphere.
Inventors:
MAEHANE YOSHIYASU
YAMAKAWA HIROYUKI
KIKUCHI RIICHI
YAMAKAWA HIROYUKI
KIKUCHI RIICHI
Application Number:
JP29234086A
Publication Date:
June 18, 1988
Filing Date:
December 10, 1986
Export Citation:
Assignee:
ULVAC CORP
International Classes:
G01L21/00; (IPC1-7): G01L21/00
Attorney, Agent or Firm:
Shigeru Yagita