Patent US4704902A successfully refreshed from Google Patents.
US4704902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustical volume/pressure measurement device
Assignee: Individual
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Filing: 1986-07-10
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Granted: 1987-11-10
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Expires: 2006-07-10
Abstract
Abstract The apparatus consists of a mechanical acoustical driver producing sound vibrations in a fluid, such as a liquid or gas, within an enclosed space. A pickup transducer positioned within the tank measures the sound vibrations of the gas within the tank and transmits the same to an amplifier and a low pass filter. Either the same or another transducer positioned in the tank measures static pressure P output of which is amplified. A divider circuit receives the dynamic pressure signal and static pressure signal and provides electrical signal E proportional to (ΔP/P). A differential amplifier receives the reference signal Erf and the signal E and supplies the error signal (Erf-E) to a gain controlled amplifier. The gain controlled amplifier amplifies the AC signal proportional to (Erf-E). The driver generates ΔP in the tank proportional to the output of the gain controlled amplifier.
Inventors
- 👤 Navin H. Doshi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:51
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/296; G01F17/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
79 words
An apparatus for measuring the volume of a gas in an enclosed space, comprising: means for producing a dynamic pressure in the gas; means for measuring the dynamic pressure; means for measuring static pressure of the gas; feedback control means for feeding measurements from said means for measuring dynamic pressure and said means for measuring static pressure to control said means for producing so that a ratio of the dynamic pressure to the static pressure is a selected constant.
Claim 2
Independent Claim
79 words
An apparatus for measuring the volume of a gas in an enclosed space, comprising: means for producing a dynamic pressure in the gas; means for measuring the dynamic pressure; means for measuring static pressure of the gas; feedback control means for feeding measurements from said means for measuring dynamic pressure and said means for measuring static pressure to control said means for producing so that a ratio of the dynamic pressure to the static pressure is a selected constant.
Claim 3
Dependent Claim
16 words
The apparatus of claim 1 wherein said means for measuring dynamic pressure has an electrical output.
Claim 4
Dependent Claim
16 words
The apparatus of claim 2 wherein said means for measuring static pressure has an electrical output.
Claim 5
Dependent Claim
24 words
The apparatus of claim 3 further including a means for converting the measurement from said means for measuring dynamic pressure to a dc output.
Claim 6
Dependent Claim
52 words
The apparatus of claim 4 further including a means for receiving the output from said means for measuring dynamic pressure and said means for measuring static pressure and producing an output proportional to a ratio of the output from said means for measuring dynamic pressure and said means for measuring static pressure.
Claim 7
Dependent Claim
42 words
The apparatus of claim 5 further including: a differential amplifier; means for supplying a reference signal to said differential amplifier, said differential amplifier having an output proportional to the difference between the reference signal and the output from said means for receiving.
Claim 8
Dependent Claim
99 words
The apparatus of claim 6 further including: a power amplifier, and an oscillator, said oscillator having an output feeding into said power amplifier to produce a signal output from said power amplifier having a selected frequency, said power amplifier receiving the output from said differential amplifier, said power amplifier having a selected gain, the gain being sufficiently high to produce an output having a selected range of amplitudes to control the amplitude of oscillation of the means for producing a dynamic pressure so that the output from said means for receiving approaches but does not equal the reference signal.
Claim 9
Dependent Claim
44 words
The apparatus of claim 1 wherein said feedback control means includes a closed loop servo system having a very high gain within the range of 1,000 to 1,000,000 so that the ratio of the dynamic pressure to the static pressure is a selected constant.
Claim 10
Independent Claim
148 words
An apparatus for measuring the specific heat ratio of a gas in an enclosed space, comprising: means for producing a dynamic pressure in the gas; means for measuring the dynamic pressure; means for measuring the static pressure of the gas; feedback control means for feeding measurements from said means for measuring dynamic pressure and and said means for measuring static pressure to control said means for producing so that a ratio of the dynamic pressure to the static pressure is a selected constant in order to obtain a measurement of the specific heat ratio in accordance with the formula: ΔP/P=γΔV/V=A (a constant) γ approaches 1.0 at very low frequency measurements (isothermal process) ΔV.sub.l =(A) (V) at very low frequency measurements ΔV.sub.h =(1/γ) (V) (A) at higher (adiabetic) frequency measurements γ=ΔV.sub.l /ΔV.sub.h where ΔV l =dynamic volume at low frequency measurement ΔV h =dynamic volume at high frequency measurement.
Claim 11
Independent Claim
148 words
An apparatus for measuring the specific heat ratio of a gas in an enclosed space, comprising: means for producing a dynamic pressure in the gas; means for measuring the dynamic pressure; means for measuring the static pressure of the gas; feedback control means for feeding measurements from said means for measuring dynamic pressure and and said means for measuring static pressure to control said means for producing so that a ratio of the dynamic pressure to the static pressure is a selected constant in order to obtain a measurement of the specific heat ratio in accordance with the formula: ΔP/P=γΔV/V=A (a constant) γ approaches 1.0 at very low frequency measurements (isothermal process) ΔV.sub.l =(A) (V) at very low frequency measurements ΔV.sub.h =(1/γ) (V) (A) at higher (adiabetic) frequency measurements γ=ΔV.sub.l /ΔV.sub.h where ΔV l =dynamic volume at low frequency measurement ΔV h =dynamic volume at high frequency measurement.
Claim 12
Independent Claim
283 words
An apparatus for measuring the volume of a gas within an enclosed space, comprising: means for emitting sound in the gas; means for measuring the dynamic pressure change of the gas induced by the means for emitting sound; means for measuring the static pressure change of the gas; a dynamic pressure signal conditioner for converting output from said means for measuring the dynamic pressure into a dc current output; a divider for receiving the output from said means for measuring the dynamic pressure and the output from said means for measuring the static pressure and producing a dc output proportional to the ratio of the output of said means for measuring the dynamic pressure to the output of said means for measuring the static pressure; means for applying a reference signal; a differential amplifier, said amplifier receiving the output from said divider and the reference signal, said amplifier amplifying the difference between said reference signal and the output from said divider; an oscillator having a selected sinusoidal output; a power amplifier, said power amplifier receiving the sinusoidal output and the output from said divider, said power amplifier amplifying the sinusoidal signal by an amount proportional to the output from the differential amplifier, the output from said power amplifier driving said means for emitting sound, the output from said power amplifier increasing or decreasing the amplitude of oscillation of the means for emitting proportional to the output from the differential amplifier such that the oscillation of the means for emitting is altered to result in change in the dynamic pressure to minimize the difference between the reference signal and the divider output; means for measuring the voltage of the output from said power amplifier.
Claim 13
Independent Claim
283 words
An apparatus for measuring the volume of a gas within an enclosed space, comprising: means for emitting sound in the gas; means for measuring the dynamic pressure change of the gas induced by the means for emitting sound; means for measuring the static pressure change of the gas; a dynamic pressure signal conditioner for converting output from said means for measuring the dynamic pressure into a dc current output; a divider for receiving the output from said means for measuring the dynamic pressure and the output from said means for measuring the static pressure and producing a dc output proportional to the ratio of the output of said means for measuring the dynamic pressure to the output of said means for measuring the static pressure; means for applying a reference signal; a differential amplifier, said amplifier receiving the output from said divider and the reference signal, said amplifier amplifying the difference between said reference signal and the output from said divider; an oscillator having a selected sinusoidal output; a power amplifier, said power amplifier receiving the sinusoidal output and the output from said divider, said power amplifier amplifying the sinusoidal signal by an amount proportional to the output from the differential amplifier, the output from said power amplifier driving said means for emitting sound, the output from said power amplifier increasing or decreasing the amplitude of oscillation of the means for emitting proportional to the output from the differential amplifier such that the oscillation of the means for emitting is altered to result in change in the dynamic pressure to minimize the difference between the reference signal and the divider output; means for measuring the voltage of the output from said power amplifier.
Claim 14
Dependent Claim
52 words
The apparatus of claim 10 further including a static pressure signal conditioner receiving the output from said means for measuring the static pressure, said static pressure conditioner amplifying the output from said means for measuring and filtering the output from said means for measuring the static pressure to remove undesired signals therefrom.
Claim 15
Dependent Claim
38 words
The apparatus of claim 10 wherein said dynamic signal conditioner amplifies the output from said means for measuring the dynamic pressure and filters the output from said means for measuring the dynamic pressure to remove undesired signals therefrom.
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) | 1990-11-09 | 1991-05-11 | 1991-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-09 | 1995-05-11 | 1995-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-09 | 1999-05-11 | 1999-11-10 | $7700.00 | Window Closed / Lapsed |