US4727748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for detecting leaks in a gas pipe line
Assignee: JFE Engineering Corp
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Filing: 1985-12-23
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Granted: 1988-03-01
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Expires: 2005-12-23
Abstract
Abstract A leak detecting method and apparatus for a gas pipe line in which the inflow rate Qin or the outflow rate Qout is measured from instant to instant at each of all the inlet and outlet ports of the gas pipe line and the presence or absence of a gas leak is determined in accordance with the measured values. The measured inflow rates Qin and outflow rates Qout are respectively integrated over a given period of time and the occurrence of a gas leak is determined when the sum Σ∫Qdt of the integrated values deviates from a predetermined value. On that occasion, in accordance with the data obtained by these calculations the relation between the integration time and the standard deviation of ∫Qindt-∫Qoutdt/∫Qindt is calculated so that in accordance with the relation an integration time T corresponding to a rate of leakage to be detected is determined and the integration over time is performed from each of a plurality of time instants shifted from each other by an integral fraction of the integration time T whereby the above-mentioned determination is made each time the integration time T is reached.
Inventors
- 👤 Hidekazu Horigome
- 👤 Takahiro Onishi
- 👤 Makoto Yamagishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:23
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/26; G01M3/28; G01M3/2807
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
157 words
A leak detecting method for a gas pipe line wherein when measuring from instant to instant an inflow rate Qin and an outflow rate Qout at each of all inlets and outlets of said gas pipe line, integrating said inflow rates Qin and said outflow rates Qout, respectively, over a predetermined period of time and determining the occurence of a gas leak when a sum Σ∫Qdt (=Σ∫Quint-Σ∫Qoutdt) of said integrated values deviates from a predetermined value, in accordance with data obtained by integrating a relation between the integration time and a standard deviation of (Σ∫Qindt-Σ∫Qoutdt)/Σ∫Qindt whereby an integration time T corresponding to a rate of leakage to be detected is determined from said relation and an integration over time is performed from each of a plurality of time instants shifted from each other by an integral fraction of said integration time T thereby making said determination of a leak each time said integration time T is reached.
Claim 2
Dependent Claim
157 words
A leak detecting method for a gas pipe line wherein when measuring from instant to instant an inflow rate Qin and an outflow rate Qout at each of all inlets and outlets of said gas pipe line, integrating said inflow rates Qin and said outflow rates Qout, respectively, over a predetermined period of time and determining the occurence of a gas leak when a sum Σ∫Qdt (=Σ∫Quint-Σ∫Qoutdt) of said integrated values deviates from a predetermined value, in accordance with data obtained by integrating a relation between the integration time and a standard deviation of (Σ∫Qindt-Σ∫Qoutdt)/Σ∫Qindt whereby an integration time T corresponding to a rate of leakage to be detected is determined from said relation and an integration over time is performed from each of a plurality of time instants shifted from each other by an integral fraction of said integration time T thereby making said determination of a leak each time said integration time T is reached.
Claim 3
Dependent Claim
170 words
A leak detecting apparatus for a gas pipe line comprising; a flow meter arranged at each of all inlets and outlets of a gas pipe line to measure from instant to instant an inflow rate Qin and an outflow rate Qout thereat; and computing means for receiving data measured by said flow meters, integrating said inflow rates Qin and said outflow rates, Qout respectively, over a predetermined period of time and calculating a sum Σ∫Qdt of said integrated values, calculating a relation between the integration time and a standard deviation of (Σ∫Qindt-Σ∫Qoutdt)/Σ∫Qindt in accordance with a result of the calculation of said sum, determining an integration time T corresponding to a rate of leakage to be detected from said calculated relation, and performing an integration over time from each of a plurality of time instants shifted from each other by an integral fraction of said integration time T whereby an alarm signal is generated when said sum Σ∫Qdt (Σ∫dindt-Σ∫doutdt) deviates from a predetermined value upon reaching said integration time T.
Claim 4
Dependent Claim
170 words
A leak detecting apparatus for a gas pipe line comprising; a flow meter arranged at each of all inlets and outlets of a gas pipe line to measure from instant to instant an inflow rate Qin and an outflow rate Qout thereat; and computing means for receiving data measured by said flow meters, integrating said inflow rates Qin and said outflow rates, Qout respectively, over a predetermined period of time and calculating a sum Σ∫Qdt of said integrated values, calculating a relation between the integration time and a standard deviation of (Σ∫Qindt-Σ∫Qoutdt)/Σ∫Qindt in accordance with a result of the calculation of said sum, determining an integration time T corresponding to a rate of leakage to be detected from said calculated relation, and performing an integration over time from each of a plurality of time instants shifted from each other by an integral fraction of said integration time T whereby an alarm signal is generated when said sum Σ∫Qdt (Σ∫dindt-Σ∫doutdt) deviates from a predetermined value upon reaching said integration time T.
Claim 5
Dependent Claim
28 words
A leak detecting apparatus for a gas pipe line according to claim 2, wherein computing means includes a CPU, a memory, an interface and a data input/output unit.
References Cited (Backward Citations)
US3105883A
Cited
US3105882A
Cited
US3505513A
Cited
US3695094A
Cited
US3723987A
Cited
US3987662A
Cited
US4090179A
Cited
DE2603715A1
Cited
US4280356A
Cited
US4306466A
Cited
US4437336A
Cited
US4308746A
Cited
US4404843A
Cited
JPH10730A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-01 | 1991-08-31 | 1992-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-01 | 1995-08-31 | 1996-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-01 | 1999-08-31 | 2000-03-01 | $7700.00 | Window Closed / Lapsed |