Patent US3019583A successfully refreshed from Google Patents.
Patent US3762223A successfully refreshed from Google Patents.
US3762223A
Expired / Lapsed
US
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Digital pressure transducer
Assignee: CONRAC AVIONIC SYSTEMS Corp A CORP OF
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Filing: 1971-09-10
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Granted: 1973-10-02
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Expires: 1991-09-10
Abstract
Abstract Fluid pressure is sensed by applying it differentially to a diaphragm, causing the diaphragm to vibrate at a natural frequency, and sensing the stressing of the diaphragm in terms of the resulting change in the natural frequency. The frequency of vibration is measured essentially by counting cycles and offsetting the count to introduce a reference pressure. Improved accuracy is obtained by forming the diaphragm of preferred magnetic materials having low temperature dependence of elasticity.
Inventors
- 👤 R Feuer
- 👤 D Ball
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:56
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0001; G01L9/0008; G01L9/0016
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
101 words
A pressure transducer, comprising in combination a resilient diaphragm formed of an alloy having substantially zero thermoelastic coefficient for oscillation frequencies higher than a predetermined threshold value, the form of the diaphragm being such that its natural frequency of oscillation is higher than said threshold value, structure for applying a fluid pressure differentially to the diaphragm to stress the same transversely, means for driving the so stressed diaphragm to oscillate at its natural frequency, sensing means responsive to the diaphragm movement, and means for deriving from the frequency of the sensed movement an indication of the magnitude of the applied pressure.
Claim 2
Dependent Claim
101 words
A pressure transducer, comprising in combination a resilient diaphragm formed of an alloy having substantially zero thermoelastic coefficient for oscillation frequencies higher than a predetermined threshold value, the form of the diaphragm being such that its natural frequency of oscillation is higher than said threshold value, structure for applying a fluid pressure differentially to the diaphragm to stress the same transversely, means for driving the so stressed diaphragm to oscillate at its natural frequency, sensing means responsive to the diaphragm movement, and means for deriving from the frequency of the sensed movement an indication of the magnitude of the applied pressure.
Claim 3
Dependent Claim
69 words
A pressure transducer according to claim 1, and in which said diaphragm consists essentially of about 48 percent iron, 42 percent nickel, 5 percent chromium and 2.5 percent titanium and has substantially zero thermoelastic coefficient for oscillation frequencies higher than a threshold value of about 800 cycles per second, and the form of the diaphragm is such that its natural frequency of oscillation is higher than said threshold value.
Claim 4
Dependent Claim
44 words
A pressure transducer according to claim 2, and in which said diapHragm driving means comprise an electrical winding magnetically coupled to the diaphragm, and circuit means for producing in the winding a current that varies periodically in definite phase relation to the diaphragm oscillation.
Claim 5
Dependent Claim
125 words
A pressure transducer, comprising in combination a resilient diaphragm, structure for applying a fluid pressure differentially to the diaphragm to stress the same transversely, means for driving the so stressed diaphragm to oscillate at its natural frequency, sensing means responsive to the diaphragm movement, means for developing clock pulses at a constant frequency higher than the frequency of diaphragm oscillation, means controlled by said sensing means for counting the clock pulses during a predetermined number of diaphragm oscillations and for offsetting the pulse count by the number of clock pulses that would occur during the same number of diaphragm oscillations at a predetermined reference pressure, and means responsive to the offset pulse count for indicating the excess of the applied pressure over the reference pressure.
Claim 6
Dependent Claim
125 words
A pressure transducer, comprising in combination a resilient diaphragm, structure for applying a fluid pressure differentially to the diaphragm to stress the same transversely, means for driving the so stressed diaphragm to oscillate at its natural frequency, sensing means responsive to the diaphragm movement, means for developing clock pulses at a constant frequency higher than the frequency of diaphragm oscillation, means controlled by said sensing means for counting the clock pulses during a predetermined number of diaphragm oscillations and for offsetting the pulse count by the number of clock pulses that would occur during the same number of diaphragm oscillations at a predetermined reference pressure, and means responsive to the offset pulse count for indicating the excess of the applied pressure over the reference pressure.
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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) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |