US4090193A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency multiplexed water leak detection system
Assignee: United States Department of the Navy
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Filing: 1976-11-24
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Granted: 1978-05-16
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Expires: 1996-11-24
Abstract
Abstract An active leak detector which uses frequency multiplexing to indicate the cation of water leaks. The circuit is composed of any number of satellite leak detectors and a master indicator circuit which monitors all detectors simultaneously. Each detector unit is identified by a unique frequency warning signal which allows the indicator circuit to isolate and display the location of the leak. Only two wires are needed to connect all the detectors to the master indicator as well as supply the necessary power to the detectors.
Inventors
- 👤 Francis E. Hinkle, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:20
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/16; G08; G08B; G08B21/00; G08B21/18; G08B21/20; G08B25/00; G08B25/01; G08B25/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
90 words
A system for detecting and locating a fluid leak comprising: a plurality of sensing means for detecting a fluid, each situated in a different location; circuitry coupled to respective sensing means for providing an electrical signal indicative of a fluid sensed by the sensing means coupled thereto, said signal having a unique frequency different from any other sensing circuitry in the system; and an indicator unit electrically coupled in parallel to all of said sensing means through their respective circuitry for providing an indication and location of said fluid leak.
Claim 2
Independent Claim
90 words
A system for detecting and locating a fluid leak comprising: a plurality of sensing means for detecting a fluid, each situated in a different location; circuitry coupled to respective sensing means for providing an electrical signal indicative of a fluid sensed by the sensing means coupled thereto, said signal having a unique frequency different from any other sensing circuitry in the system; and an indicator unit electrically coupled in parallel to all of said sensing means through their respective circuitry for providing an indication and location of said fluid leak.
Claim 3
Dependent Claim
31 words
A system as recited in claim 1 wherein said circuitry includes an astable multivibrator to provide said unique frequency, said unique frequency determined by the RC time constant of said multivibrator.
Claim 4
Dependent Claim
42 words
A system as recited in claim 2 wherein said sensing means comprises a pair of electrodes and said fluid comprises water, whereby when water is present between said electrodes, current flows therebetween to cause said circuitry to provide said unique oscillator frequency.
Claim 5
Dependent Claim
47 words
A system as recited in claim 3 further including a power source; and only a single pair of lines to provide said power to said sensing means, said circuitry and said indicator unit, as well as provide the output signals of said circuitry to said indicator unit.
Claim 6
Dependent Claim
23 words
A system as recited in claim 4 wherein said circuitry comprises a CMOS unit arranged in a detecting, inverting and astable multivibrator arrangement.
Claim 7
Dependent Claim
42 words
A system as recited in claim 5 wherein said indicator unit comprises a CMOS unit arranged in a gate amplifier arrangement and an aural indicator to provide a tone indicative of said unique circuitry signals thereby identifying the location of the leak.
Claim 8
Dependent Claim
35 words
A system as recited in claim 4 further including: an isolation network coupled between said power source and said circuitry whereby each circuit is isolated from said power source and each of the other circuits.
Claim 9
Dependent Claim
28 words
A system as recited in claim 6 further including: filter means comprising an inductor in parallel with a resistor to isolate the power source from circuit output signals.
Claim 10
Dependent Claim
24 words
A system as recited in claim 8 wherein said indicating means includes a visual display to provide the frequency of oscillation of said circuit.
Claim 11
Dependent Claim
48 words
A system as recited in claim 9 wherein said power source comprises a 9 volt DC source and wherein said isolation network includes a capacitor chosen to be 1/1000 F L farads, where F L is the lowest frequency of oscillation of an astable multivibrator in said system.
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) | 1981-05-15 | 1981-11-14 | 1982-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-15 | 1985-11-14 | 1986-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-15 | 1989-11-14 | 1990-05-16 | $7700.00 | Window Closed / Lapsed |