Title:
IONIZATION VACUUM GAUGE CONTROL DEVICE
Document Type and Number:
Japanese Patent JP3734913
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a technique capable of surely preventing filament disconnection.
SOLUTION: When pressure is to be found on the basis of the magnitude of an ionic current I, by collecting ion formed by gas molecule ionization with a collector C after impressing positive voltage on the grid G of an ionization vacuum gauge 1 using an ionization vacuum gauge control device and producing thermion by heating a filament F, magnitude of a filament current If energizing through the filament F is directly detected by providing an overcurrent protection circuit 3 on the ionization vacuum gauge control device and the filament current If is limited so as not to exceed the specific upper value. It is possible to infallibly protect overcurrent because the filament current If can be limited without detecting an emission current Ie.
Inventors:
Guo Ming
Shizuo Nakamura
Shizuo Nakamura
Application Number:
JP2719997A
Publication Date:
January 11, 2006
Filing Date:
January 27, 1997
Export Citation:
Assignee:
ULVAC, Inc.
International Classes:
G01L21/30; G01L21/32; (IPC1-7): G01L21/30
Domestic Patent References:
| JP64010143A |
Attorney, Agent or Firm:
Shigeo Ishijima
Hideki Abe
Hideki Abe
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