US4596133A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and methods for measuring fluid flow parameters
Assignee: Panametrics LLC
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Filing: 1983-07-29
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Granted: 1986-06-24
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Expires: 2003-07-29
Abstract
Abstract An apparatus and method for measuring fluid flow parameters operate under conditions wherein the composition of the fluid flow can change rapidly thereby changing the speed of sound within the fluid and wherein the actual flow rate can change rapidly thereby further changing the transit time of acoustic energy traversing an interrogation path within the fluid. The apparatus determines the speed of sound in the fluid and the fluid flow velocity by measuring an upstream and a downstream transit time of acoustic energy within the fluid. The fluid is typically flowing within a conduit, and the transducers for transmitting and receiving the acoustic energy are precisely and carefully installed in the conduit. The measurements also allow an estimate to be made of the average molecular weight of gases passing through the conduit and hence of the mass flow rate of a gas. The measurements are taken at a frequency sufficient to satisfy the Nyquist criterion with regard to the maximum frequencies of interest for the fluid flow parameters being measured. Special techniques are developed for enabling transducer placement in preexisting conduit arrangements wherein access to the conduit is limited.
Inventors
- 👤 Jack W. Smalling
- 👤 Leonard D. Braswell
- 👤 Lawrence C. Lynnworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:26
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/24; G01F; G01F1/00; G01F1/66; G01F1/662; G01F1/667; G01N; G01N29/00; G01N29/02; G01N29/024; G01N29/44; G01N29/4454; G01P; G01P5/00; G01P5/24; G01P5/245; G01N2291/00; G01N2291/02; G01N2291/025; G01N2291/0258; G01N2291/028; G01N2291/02818; G01N2291/02836; G01N2291/02881; G01N2291/0289
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
71 words
An apparatus for determining average molecular weight of a gas flowing through a conduit comprising transit time measuring means for measuring the transit time of acoustic energy traversing a path across said conduit, and means for accurately determining in response to said transit time, the average molecular weight of the gas flowing through the conduit at the time of said transit time measurement, said gas having an unknown specific heat ratio.
Claim 2
Independent Claim
71 words
An apparatus for determining average molecular weight of a gas flowing through a conduit comprising transit time measuring means for measuring the transit time of acoustic energy traversing a path across said conduit, and means for accurately determining in response to said transit time, the average molecular weight of the gas flowing through the conduit at the time of said transit time measurement, said gas having an unknown specific heat ratio.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1 further wherein said determining means employs an empirical relationship between molecular weight and the specific heat ratio of the gas for determining said average molecular weight.
Claim 4
Dependent Claim
16 words
The apparatus of claim 2 further wherein said relationship can be approximated by a straight line.
Claim 5
Dependent Claim
38 words
The apparatus of claim 1 further comprising means for alternately and repetitively measuring said transit time in an upstream and a downstream direction, and said determining means being responsive to said transit time measurements for averaging said measurements.
Claim 6
Dependent Claim
29 words
The apparatus of claim 4 further wherein said determining means comprises means for temporally filtering said transit time measurements for responding to recent measurements and for ignoring past measurements.
Claim 7
Dependent Claim
22 words
The apparatus of claim 5 wherein said filtering means includes means for effecting a truncated binary weighting of said transit time measurements.
Claim 8
Independent Claim
64 words
A method for determining average molecular weight of a gas flowing through a conduit comprising measuring the transit time of acoustic energy traversing a path across said conduit, and accurately determining, in response to said transit time, the average molecular weight of the gas flowing through the conduit at the time of said transit time measurement, said gas having an unknown specific heat ratio.
Claim 9
Independent Claim
64 words
A method for determining average molecular weight of a gas flowing through a conduit comprising measuring the transit time of acoustic energy traversing a path across said conduit, and accurately determining, in response to said transit time, the average molecular weight of the gas flowing through the conduit at the time of said transit time measurement, said gas having an unknown specific heat ratio.
Claim 10
Dependent Claim
30 words
The method of claim 7 further comprising the step of employing an empirical relationship between molecular weight and specific heat ratio of the gas for determining said average molecular weight.
Claim 11
Dependent Claim
40 words
The molecular weight determining method of claim 8 further comprising the steps of employing received acoustic measurement data for determining the temperature and pressure of said fluid whereby mass flow rate can be determined using solely acoustic transducer derived data.
Claim 12
Dependent Claim
39 words
The method of claim 7 further comprising the steps of alternately and repetitively measuring said transit time in upstream and downstream directions, and responding to said transit time measurements for averaging said measurements to thereby smooth the transit time
Claim 13
Dependent Claim
21 words
The method of claim 10 further wherein said averaging step comprises employing a truncated binary weighting of said transit time data.
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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) | 1989-06-23 | 1989-12-23 | 1990-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-23 | 1993-12-23 | 1994-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-23 | 1997-12-23 | 1998-06-24 | $7700.00 | Window Closed / Lapsed |