US3968675A
Expired / Lapsed
US
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Method and apparatus for preparing a mass spectrometer leak detector system for operation
Assignee: Varian Medical Systems Inc
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Filing: 1974-06-07
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Granted: 1976-07-13
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Expires: 1994-06-07
Abstract
Abstract A leak detector system comprising a mass spectrometer tuned to detect the presence of helium test gas is prepared for operation by reference to the partial pressure of helium in air.
Inventors
- 👤 Walton E. Briggs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:17
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/20; G01M3/202; G01M3/205
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
83 words
A method of preparing a mass spectrometer leak detector system for operation in testing for leaks, said method comprising the steps of establishing in said mass spectrometer a reduced pressure and then introducing substantially pure atmospheric air into said air system to provide in said mass spectrometer a partial pressure of the helium in said air sufficient to be detectable by said mass spectrometer while preventing the introduction of said air into the system in an amount which will damage said mass spectrometer.
Claim 2
Independent Claim
83 words
A method of preparing a mass spectrometer leak detector system for operation in testing for leaks, said method comprising the steps of establishing in said mass spectrometer a reduced pressure and then introducing substantially pure atmospheric air into said air system to provide in said mass spectrometer a partial pressure of the helium in said air sufficient to be detectable by said mass spectrometer while preventing the introduction of said air into the system in an amount which will damage said mass spectrometer.
Claim 3
Dependent Claim
28 words
A method as claimed in claim 1 wherein helium in the air introduced into the system is passed upstream through a diffusion pump to reach the mass spectrometer.
Claim 4
Dependent Claim
42 words
A method as claimed in claim 1 wherein helium in the air introduced into the system is passed to the mass spectrometer upstream through a pump which is less effective in pumping helium than it is in pumping other constituents of air.
Claim 5
Dependent Claim
20 words
A method as claimed in claim 1 comprising the step of tuning the mass spectrometer with said helium provided therein.
Claim 6
Dependent Claim
38 words
A method as claimed in claim 1 comprising determining the partial pressure of said helium in the mass spectrometer based on helium presence in air in the ratio of 1 part of helium per 200,000 parts of air.
Claim 7
Dependent Claim
24 words
A method as claimed in claim 5 comprising the step of calibrating said mass spectrometer based on the determined partial pressure of helium therein.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |