Patent US3717038A successfully refreshed from Google Patents.
US3717038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct current pressure ratio circuit
Assignee: General Electric Co
•
Filing: 1971-04-30
•
Granted: 1973-02-20
•
Expires: 1991-04-30
Abstract
Abstract An electrical circuit is disclosed which provides an output which indicates the ratio of a sensed pressure differential to a sensed absolute pressure and thereby approximates the Mach number of air flow in a duct. A pair of transducers respectively sense the differential between total and static pressure, and static pressure, per se, in the duct. The pressure differential signal provides an input to an operational amplifier circuit, while the absolute pressure signal forms part of a feedback loop to the operational amplifier. A non-linear compensation network is provided to prevent null drift of the operational amplifier.
Inventors
- 👤 D Plett
- 👤 L Owen
- 👤 R Tenkman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:17
CPC Classifications
G; G01; G01L; G01L15/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
123 words
An electrical circuit comprising: amplifier means having a gain (G) and providing an output signal (E0), means for providing an input signal (Ei) to be amplified by said amplifier means, means for providing a feedback signal (H) to said amplifier means, said input signal generating means including a first pressure transducer such that (Ei) is proportional to a first pressure level and said feedback signal generating means including a second pressure transducer such that (H) is proportional to a second pressure level whereby said output signal is proportional to the ratio of said first pressure level divided by said second pressure level, and said signal feedback generating means including means for compensating for the zero pressure offset voltage of said second pressure transducer.
Claim 2
Dependent Claim
123 words
An electrical circuit comprising: amplifier means having a gain (G) and providing an output signal (E0), means for providing an input signal (Ei) to be amplified by said amplifier means, means for providing a feedback signal (H) to said amplifier means, said input signal generating means including a first pressure transducer such that (Ei) is proportional to a first pressure level and said feedback signal generating means including a second pressure transducer such that (H) is proportional to a second pressure level whereby said output signal is proportional to the ratio of said first pressure level divided by said second pressure level, and said signal feedback generating means including means for compensating for the zero pressure offset voltage of said second pressure transducer.
Claim 3
Dependent Claim
123 words
An electrical circuit comprising: amplifier means having a gain (G) and providing an output signal (E0), means for providing an input signal (Ei) to be amplified by said amplifier means, means for providing a feedback signal (H) to said amplifier means, said input signal generating means including a first pressure transducer such that (Ei) is proportional to a first pressure level and said feedback signal generating means including a second pressure transducer such that (H) is proportional to a second pressure level whereby said output signal is proportional to the ratio of said first pressure level divided by said second pressure level, and said signal feedback generating means including means for compensating for the zero pressure offset voltage of said second pressure transducer.
Claim 4
Dependent Claim
123 words
An electrical circuit comprising: amplifier means having a gain (G) and providing an output signal (E0), means for providing an input signal (Ei) to be amplified by said amplifier means, means for providing a feedback signal (H) to said amplifier means, said input signal generating means including a first pressure transducer such that (Ei) is proportional to a first pressure level and said feedback signal generating means including a second pressure transducer such that (H) is proportional to a second pressure level whereby said output signal is proportional to the ratio of said first pressure level divided by said second pressure level, and said signal feedback generating means including means for compensating for the zero pressure offset voltage of said second pressure transducer.
Claim 5
Dependent Claim
37 words
An electrical circuit as recited in claim 1 wherein said feedback signal generating means further includes means for inverting the output signal of said amplifier means and for applying the inverted signal to said second pressure transducer.
Claim 6
Dependent Claim
29 words
An electrical circuit as recited in claim 2 wherein said first pressure transducer is a pressure differential sensor and said second pressure transducer is an absolute pressure level sensor.
Claim 7
Dependent Claim
19 words
An electrical circuit as recited in claim 3 further including means for minimizing null drift of said amplifier means.
Claim 8
Dependent Claim
165 words
An electrical circuit for indicating the Mach number of flow within a duct comprising: amplifier means having a gain (G) and providing an output signal (E0), means connected to said amplifier means for generating an input signal (Ei) to be amplified by said amplifier means, said input signal generating means providing a signal proportional to the difference between the total pressure and the static pressure within said duct, means connected to said amplifier means for generating a feedback signal (H) therefor, said feedback signal being proportional to the static pressure within said duct whereby said output signal is proportional to the ratio of said differential signal divided by said static pressure signal said input signal generating means including a pressure transducer subjected to said differential pressure signal and said feedback signal generating means including a pressure transducer subjected to said static pressure signal, and said feedback signal generating means including means for compensating for the zero pressure offset voltage of said static pressure signal transducer.
Claim 9
Dependent Claim
165 words
An electrical circuit for indicating the Mach number of flow within a duct comprising: amplifier means having a gain (G) and providing an output signal (E0), means connected to said amplifier means for generating an input signal (Ei) to be amplified by said amplifier means, said input signal generating means providing a signal proportional to the difference between the total pressure and the static pressure within said duct, means connected to said amplifier means for generating a feedback signal (H) therefor, said feedback signal being proportional to the static pressure within said duct whereby said output signal is proportional to the ratio of said differential signal divided by said static pressure signal said input signal generating means including a pressure transducer subjected to said differential pressure signal and said feedback signal generating means including a pressure transducer subjected to said static pressure signal, and said feedback signal generating means including means for compensating for the zero pressure offset voltage of said static pressure signal transducer.
Claim 10
Dependent Claim
19 words
An electrical circuit as recited in claim 5 further including means for minimizing null drift of sAid amplifier means.
Claim 11
Dependent Claim
37 words
An electrical circuit as recited in claim 6 wherein said feedback signal generating means further includes means for inverting the output signal of said amplifier means and for applying the inverted signal to said second pressure transducer.
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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |