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US4029889A
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Fluid-leak detector cable
Assignee: Asahi Engineering and Construction Co Ltd
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Filing: 1975-04-04
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Granted: 1977-06-14
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Expires: 1995-04-04
Abstract
Abstract A cable for detecting, in a stable and waterproof way, any leak of petroleum, petroleum product, or other fluid from an underground pipeline by means of a change in the electrostatic capacity between inner and outer conductors of the cable due to permeation by the leaking fluid. The cable offers constant, uninterrupted monitoring of such a pipeline with no limit to the watching range, and can accurately locate even a minor leak. The invention also involves a method of installing a detection system using such a detector cable, and a detection method which depends on electric pulses as means for detecting such a leak.
Inventors
- 👤 Shoken Mizuochi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:11
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/042; G01M3/045; G01M3/16; G01M3/165; Y; Y10; Y10S; Y10S138/00; Y10S138/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
84 words
A fluid-leak detector cable which comprises an inner conductor, an outer conductor, and a serving layer for retaining a leaked fluid disposed therebetween, said layers being coaxially disposed with respect to each other, said outer conductor being provided with an exterior layer of a porous, permeable, plastic film which is permeable to hydrocarbons but not permeable to water, said film having an open-cell structure which is not soluble in the leaking fluid, thereby being adapted to retain the leaking fluid within the serving layer.
Claim 2
Dependent Claim
84 words
A fluid-leak detector cable which comprises an inner conductor, an outer conductor, and a serving layer for retaining a leaked fluid disposed therebetween, said layers being coaxially disposed with respect to each other, said outer conductor being provided with an exterior layer of a porous, permeable, plastic film which is permeable to hydrocarbons but not permeable to water, said film having an open-cell structure which is not soluble in the leaking fluid, thereby being adapted to retain the leaking fluid within the serving layer.
Claim 3
Dependent Claim
38 words
The fluid-leak detector cable of claim 1, wherein the porous, permeable, plastic layer is polytetrafluoroethylene which is made into a continuous, porous, permeable film of an open-cell structure having an average pore diameter of 0.5 to 5.0 microns.
Claim 4
Dependent Claim
18 words
The fluid-leak detector cable of claim 2, wherein the open-cell structure has a porosity of 85 to 95%.
Claim 5
Dependent Claim
22 words
The fluid-leak detector cable of claim 1, wherein the porous, permeable, plastic film is highly water repellant and permeable to only petroleum.
Claim 6
Dependent Claim
17 words
The fluid-leak detector cable of claim 1, wherein the serving layer is a continuous layer of jute.
Claim 7
Dependent Claim
30 words
The fluid-leak detector cable of claim 1, wherein the serving layer comprises a continuous porous, permeable, plastic film having an open-cell structure which is not soluble in the leaking fluid.
Claim 8
Dependent Claim
36 words
The fluid-leak detector cable of claim 6, wherein the serving layer is a continuous, porous, permeable film of polytetrafluoroethylene having an average pore diameter of 0.5 to 5.0 microns and a porosity of 85 to 95%.
Claim 9
Dependent Claim
22 words
The fluid-leak detector cable of claim 1, wherein a continuous insulating layer is disposed between the inner conductor and the serving layer.
Claim 10
Dependent Claim
83 words
A fluid-leak detector cable which comprises two conductors disposed substantially parallel to each other, each of said conductors being individually provided with a serving layer disposed therearound and each of said conductors and their corresponding serving layers being provided with a common covering layer, said serving layers and said covering layer being made of a porous, permeable plastic film which is permeable to hydrocarbons but not permeable to water, said film having an open-cell structure which is not soluble in the leaking fluid.
Claim 11
Dependent Claim
83 words
A fluid-leak detector cable which comprises two conductors disposed substantially parallel to each other, each of said conductors being individually provided with a serving layer disposed therearound and each of said conductors and their corresponding serving layers being provided with a common covering layer, said serving layers and said covering layer being made of a porous, permeable plastic film which is permeable to hydrocarbons but not permeable to water, said film having an open-cell structure which is not soluble in the leaking fluid.
Claim 12
Independent Claim
125 words
A method for detecting a hydrocarbon leak from an underground pipeline which comprises laying a fluid-leak detector cable in close proximity to and substantially parallel to the underground pipeline so that any leaking hydrocarbon fluid may permeate the fluid-leak detector cable, said fluid-leak detector cable comprising an inner conductor and an outer conductor, and a serving layer for retaining the leaked fluid disposed therebetween, said layers being coaxially disposed with respect to each other, said outer conductor being provided with an exterior layer of a porous, permeable, plastic film which is permeable to hydrocarbons, but not permeable to water, said film having an open-cell structure which is not soluble in the leaking fluid, thereby being adapted to retain the leaking fluid within the serving layer.
Claim 13
Independent Claim
125 words
A method for detecting a hydrocarbon leak from an underground pipeline which comprises laying a fluid-leak detector cable in close proximity to and substantially parallel to the underground pipeline so that any leaking hydrocarbon fluid may permeate the fluid-leak detector cable, said fluid-leak detector cable comprising an inner conductor and an outer conductor, and a serving layer for retaining the leaked fluid disposed therebetween, said layers being coaxially disposed with respect to each other, said outer conductor being provided with an exterior layer of a porous, permeable, plastic film which is permeable to hydrocarbons, but not permeable to water, said film having an open-cell structure which is not soluble in the leaking fluid, thereby being adapted to retain the leaking fluid within the serving layer.
Claim 14
Dependent Claim
52 words
The method of detecting a hydrocarbon leak from an underground pipeline as defined in claim 10, wherein an electrical pulse is transmitted from one end of the fluid-leak detector cable and the reflected wave of the pulse at the starting end is observed to determine whether or not a leak has occurred.
Claim 15
Dependent Claim
55 words
The method of detecting a hydrocarbon leak from an underground pipeline as defined in claim 10, wherein an electrical pulse is transmitted from one end of the fluid-leak detector cable and the arriving wave of the pulse at the opposite end of said cable is observed to determine whether or not a leak has occurred.
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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) | 1980-06-13 | 1980-12-13 | 1981-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-13 | 1984-12-13 | 1985-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-13 | 1988-12-13 | 1989-06-14 | $7700.00 | Window Closed / Lapsed |