US4506553A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for measuring small values of air flow
Assignee: United States Department of the Army
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Filing: 1983-09-30
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Granted: 1985-03-26
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Expires: 2003-09-30
Abstract
Abstract A gas flow rotor cyclically connects a microphone to a dynamic flow press and then a reference static flow pressure. The microphone converts the pressures to a resultant alternating differential signal providing a first input to a phase-locked amplifier. A second amplifier input is derived from an optical pickup mounted on the rotor. Only the AC component of the converted microphone signal, which has a fixed phase relationship to that of the rotor, is amplified. A readout connected in circuit with the amplifier indicates the dynamic flow pressure.
Inventors
- 👤 Charles W. Bruce
- 👤 Kenneth E. Kunkel
- 👤 Fred C. Webb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:46
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/34; G01F1/36
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
97 words
A sensor for measuring gas flow comprising: a housing having (a) a first orifice for receiving dynamic gas flow therethrough, (b) a second orifice spaced from the first and communicating with a static gas or other reference environment, (c) a third orifice spaced from the other two and communicating with a microphone; rotor means located inwardly of the housing and having first and second curved passageways therein for alternately completing a passage between the third orifice, and the first then second orifices thus subjecting the microphone to a resultant acoustic wave dependent upon the dynamic gas flow.
Claim 2
Dependent Claim
97 words
A sensor for measuring gas flow comprising: a housing having (a) a first orifice for receiving dynamic gas flow therethrough, (b) a second orifice spaced from the first and communicating with a static gas or other reference environment, (c) a third orifice spaced from the other two and communicating with a microphone; rotor means located inwardly of the housing and having first and second curved passageways therein for alternately completing a passage between the third orifice, and the first then second orifices thus subjecting the microphone to a resultant acoustic wave dependent upon the dynamic gas flow.
Claim 3
Dependent Claim
27 words
The subject matter of claim 1 together with means mounted in the housing and adjacent the rotor means for photo-optically detecting the rotation of the rotor means.
Claim 4
Dependent Claim
39 words
The structure set forth in claim 2 together with a phase-locked amplifier having first and second inputs, said first input being connected to said microphone, and said second input being connected to the output of said photo-optic detecting means.
Claim 5
Dependent Claim
25 words
The subject matter set forth in claim 3 with indicating means connected in circuit with the output of the amplifier for displaying gas flow data.
Claim 6
Dependent Claim
124 words
A sensor for measuring air flow comprising: a housing having a first inlet; means for directing dynamic ambient air pressure to the inlet; an outlet in the housing spaced from the first inlet; a microphone located adjacent the outlet; rotor means located in the housing for connecting the first inlet and the outlet at a preselected position of the rotor means thereby subjecting the microphone to the dynamic ambient air pressure condition at the first inlet; a second inlet in the housing spaced from the first inlet; means connecting the second inlet with an external static or other airflow reference; and means rotating the rotor means to another position for causing the microphone to sense a second pressure condition corresponding to the airflow reference.
Claim 7
Dependent Claim
124 words
A sensor for measuring air flow comprising: a housing having a first inlet; means for directing dynamic ambient air pressure to the inlet; an outlet in the housing spaced from the first inlet; a microphone located adjacent the outlet; rotor means located in the housing for connecting the first inlet and the outlet at a preselected position of the rotor means thereby subjecting the microphone to the dynamic ambient air pressure condition at the first inlet; a second inlet in the housing spaced from the first inlet; means connecting the second inlet with an external static or other airflow reference; and means rotating the rotor means to another position for causing the microphone to sense a second pressure condition corresponding to the airflow reference.
Claim 8
Dependent Claim
29 words
The subject matter set forth in claim 5 together with means mounted in the housing and adjacent the rotor means for photo-optically detecting the rotation of the rotor means.
Claim 9
Dependent Claim
40 words
The subject matter set forth in claim 6 further comprising a phase-locked amplifier having first and second inputs, said first input being connected to said microphone, and said second input being connected to the output of said photo-optic detecting means.
Claim 10
Dependent Claim
37 words
The subject matter set forth in claim 7 wherein the means rotating the rotor means comprises a motor coaxially mounted to the housing and having a shaft passing through the housing for connection to the rotor means.
Claim 11
Dependent Claim
25 words
The subject matter set forth in claim 8 together with means for changing a signal at the output of the amplifier to a digital signal.
Claim 12
Dependent Claim
26 words
The subject matter set forth in claim 9 together with display means connected to the changing means output for indicating values of measured dynamic air flow.
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) | 1988-03-25 | 1988-09-24 | 1989-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-25 | 1992-09-24 | 1993-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-25 | 1996-09-24 | 1997-03-26 | $7700.00 | Window Closed / Lapsed |