US3795145A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable throat venturi airspeed sensor
Assignee: Honeywell Inc
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Filing: 1972-03-23
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Granted: 1974-03-05
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Expires: 1992-03-23
Abstract
Abstract An airspeed sensor utilizes a venturi in which the throat area is adjustable. The fluid pressures in the inlet region and the throat region are measured. The throat area of the duct is programmed by a servo as a function of the pressure ratio between inlet and throat so as to cause the pressure ratio to be a function of the Mach number of the airflow at the entrance to the venturi. An output signal representing the equivalent airspeed is taken from a potentiometer which is energized through a shaping circuit from the inlet region pressure sensor. The setting of the potentiometer is adjusted in accordance with the setting of the variable throat mechanism of the venturi.
Inventors
- 👤 H Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:35
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/34; G01F1/36; G01F1/40; G01F1/44; G01F1/363; G01P; G01P5/00; G01P5/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
113 words
Fluid flow measuring apparatus comprising venturi means, control means, an output means; said venturi means including inlet means having fixed cross-sectional dimensions and throat means having variable cross-sectional dimensions; said control means including means to sense fluid pressures in said inlet and throat means and means to adjust the cross-sectional dimensions of said throat means in accordance with the pressure detected by said sensing means; said output means including an output potentiometer energized in response to the fluid pressure detected by the inlet pressure sensing means and mechanically adjusted by the throat adjusting means in said control means, said output potentiometer further being arranged to provide an output signal at its adjustable arm.
Claim 2
Dependent Claim
113 words
Fluid flow measuring apparatus comprising venturi means, control means, an output means; said venturi means including inlet means having fixed cross-sectional dimensions and throat means having variable cross-sectional dimensions; said control means including means to sense fluid pressures in said inlet and throat means and means to adjust the cross-sectional dimensions of said throat means in accordance with the pressure detected by said sensing means; said output means including an output potentiometer energized in response to the fluid pressure detected by the inlet pressure sensing means and mechanically adjusted by the throat adjusting means in said control means, said output potentiometer further being arranged to provide an output signal at its adjustable arm.
Claim 3
Dependent Claim
120 words
Fluid flow measuring apparatus comprising a venturi, control means, an output means; said venturi including an inlet portion having a fixed cross-sectional area and a throat portion having a variable cross-sectional area; said control means including means to sense a fluid pressure differential between said inlet and throat portions and means to adjust the cross-sectional area of said throat portion in accordance with changes in differential pressure detected by said sensing means; said output means including an output potentiometer energized in response to the fluid pressure detected by the inlet pressure sensing means and mechanically adjusted by the throat adjusting means in said control means, said output potentiometer further being arranged to provide an output signal at its adjustable arm.
Claim 4
Dependent Claim
120 words
Fluid flow measuring apparatus comprising a venturi, control means, an output means; said venturi including an inlet portion having a fixed cross-sectional area and a throat portion having a variable cross-sectional area; said control means including means to sense a fluid pressure differential between said inlet and throat portions and means to adjust the cross-sectional area of said throat portion in accordance with changes in differential pressure detected by said sensing means; said output means including an output potentiometer energized in response to the fluid pressure detected by the inlet pressure sensing means and mechanically adjusted by the throat adjusting means in said control means, said output potentiometer further being arranged to provide an output signal at its adjustable arm.
Claim 5
Dependent Claim
33 words
The apparatus of claim 2 wherein said control means includes means to reduce the cross-sectional area of said throat portion in response to a reduction in differential pressure detected by said sensing means.
Claim 6
Dependent Claim
38 words
The apparatus of claim 3 wherein said venturi is in the form of a rectangular duct and said throat portion includes a flap-like adjustable throat member rotatable about a transverse axis disposed in one wall of said duct.
Claim 7
Dependent Claim
19 words
The apparatus of claim 4 wherein said transverse axis is at the upstream end of said adjustable throat member.
Claim 8
Dependent Claim
52 words
The apparatus of claim 5 wherein said adjustable throat member is secured on a rotatable shaft disposed along said transverse axis, and said adjustment means includes a servo motor mechanically coupled to said rotatable shaft, said servo motor being driven in response to the differential fluid pressure detected by said sensing means.
Claim 9
Dependent Claim
66 words
The apparatus of claim 6 wherein said differential fluid pressure sensing means includes first and second means to detect the pressure in said inlet and throat portions, respectively, means to convert the detected pressures into electrical signals representative of the logarithms of the detected pressures, and differential amplifying means coupled to receive said electrical signals, said amplifying means being further coupled to drive said servo motor.
Claim 10
Dependent Claim
30 words
The apparatus of claim 7 further including a feedback potentiometer mechanically adjusted in accordance with the angular position of said shaft and electrically coupled to the input of said amplifier.
Claim 11
Dependent Claim
35 words
The apparatus of claim 8 wherein said feedback potentiometer has a linear resistance characteristic and wherein the adjustable arm of said potentiometer is coupled to the input of said amplifier in a negative feedback relationship.
Claim 12
Dependent Claim
73 words
The apparatus of claim 9 further containing signal shaping means for converting the sigNal from the inlet portion fluid sensing means into an electrical signal equivalent to the square root of the detected pressure and means for energizing said output potentiometer with said square root signal, said output potentiometer being proportioned to provide a resistance characteristic representative of the inlet Mach number and pressure equivalent to each position of the adjustable throat member.
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) | 1977-03-04 | 1977-09-03 | 1978-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-04 | 1981-09-03 | 1982-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-04 | 1985-09-03 | 1986-03-05 | $7700.00 | Window Closed / Lapsed |