Patent US5237281A successfully refreshed from Google Patents.
US5237281A
Expired / Lapsed
US
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Ion drag air flow meter
Assignee: Raytheon Co
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Filing: 1990-11-13
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Granted: 1993-08-17
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Expires: 2010-11-13
Abstract
Abstract An ion drag air flow meter (10) including a gas ionizer (16), an ion collector (14) and apparatus (30) for converting the collected ions into a signal providing an indication of the flow of a gas (40).
Inventors
- 👤 Jackie R. Webster
- 👤 David B. Chang
- 👤 Keith V. Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:34
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/14; G01F23/18; G01F1/00; G01F1/704; G01F1/7042; G01F1/7046
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
132 words
An apparatus for measuring the flow of a fluid comprising: a voltage source having a first and second terminal; ion chamber means for collecting ions, said ion chamber means including an outer conductor connected to a first terminal of the voltage source and an inner conductor connected to a second terminal of the voltage source, the outer conductor surrounding said inner conductor; annular radioisotope means disposed at a first end of said chamber means for ionizing the fluid, said radioisotope means consisting essentially of an ionizing source disposed on a peripheral edge of said outer conductor; and circuit means electrically coupled to the ion chamber means and the voltage source for converting a signal indicative of the collected ions into a signal to provide an indication of the flow of the fluid.
Claim 2
Independent Claim
132 words
An apparatus for measuring the flow of a fluid comprising: a voltage source having a first and second terminal; ion chamber means for collecting ions, said ion chamber means including an outer conductor connected to a first terminal of the voltage source and an inner conductor connected to a second terminal of the voltage source, the outer conductor surrounding said inner conductor; annular radioisotope means disposed at a first end of said chamber means for ionizing the fluid, said radioisotope means consisting essentially of an ionizing source disposed on a peripheral edge of said outer conductor; and circuit means electrically coupled to the ion chamber means and the voltage source for converting a signal indicative of the collected ions into a signal to provide an indication of the flow of the fluid.
Claim 3
Dependent Claim
16 words
The apparatus of claim 1 wherein said radioisotope means includes a radioisotope for emitting beta particles.
Claim 4
Dependent Claim
73 words
The apparatus of claim 1 further comprising: a second ion chamber means, said second ion chamber means including a second outer conductor connected to said first terminal of said voltage source and a second inner conductor connected to said second terminal of said voltage source, said second outer conductor surrounding said second inner conductor; and second annular radioisotope means disposed at a second end of said second chamber means to ionizing said fluid.
Claim 5
Dependent Claim
34 words
The apparatus of claim 3, said first radioisotope being disposed at an intake end of said first outer conductor and said second radioisotope being disposed at an exhaust end of said second outer conductor.
Claim 6
Dependent Claim
38 words
The apparatus of claim 1 wherein said circuit means includes an operational amplifier coupled to said ion chamber means and said voltage source to provide an indication of the direction and/or velocity of the flow of the fluid.
Claim 7
Dependent Claim
14 words
The apparatus of claim 1 wherein the outer and inner conductors are concentric cylinders.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-16 | 1997-02-15 | 1997-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-16 | 2001-02-15 | 2001-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-16 | 2005-02-15 | 2005-08-17 | $7700.00 | Window Closed / Lapsed |