US3697671A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric cables
Assignee: Pyrotenax Ltd
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Filing: 1971-03-03
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Granted: 1972-10-10
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Expires: 1991-03-03
Abstract
Abstract An electric power or communication cable has at least one core comprising an insulated conductor of aluminum or an aluminumbased alloy of high conductivity, a plastics sheath and, incorporated in the cable, a mineral insulated cable of a crosssection that is small in comparison with the overall crosssection of the cable. The mineral insulated cable has a sheath of aluminum or an aluminum-based alloy, is located outside the cable core or cores, and is adapted to indicate when the sheath of the mineral insulated cable has corroded to a sufficient extent to permit ingress of moisture therethrough. The mineral insulated cable may be embedded in the plastics sheath or it may replace one or more elements of a concentric neutral conductor of aluminum or an aluminum-based alloy.
Inventors
- 👤 Herbert William Mansfie Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:17
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/042; G01M3/045; G01M3/16; G01M3/18; G01M3/181
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
19 words
An electric cable as claimed in claim 1, wherein the mineral insulated cable is embedded in the plastics sheath.
Claim 2
Dependent Claim
23 words
An electric cable as claimed in claim 2, wherein several mineral insulated cables are embedded at peripherally spaced intervals in the plastics sheath.
Claim 3
Dependent Claim
29 words
An electric cable as claimed in claim 1, wherein the sheath of the mineral insulated cable is of the same material as that of the core conductor or conductors.
Claim 4
Dependent Claim
34 words
An electric cable as claimed in claim 1, wherein the mineral insulated cable is flattened to a cross-sectional shape approximating to that of a strip without any detrimental effect on its corrosion detecting performance.
Claim 5
Dependent Claim
161 words
An electric power cable having at least one core comprising an insulated conductor, a concentric neutral conductor comprising metal elements applied about the core or cores, and a plastics sheath, at least a metal element of the neutral conductor and the or a core conductor being of a material selected from the group of materials consisting of aluminum and aluminum-based alloys of high conductivity, wherein a mineral insulated cable, which has a sheath of a material selected from the group of materials consisting of aluminum and aluminum-based alloys and is of a cross-section that is small in comparison with the overall cross-section of the cable, replaces at least one element of the concentric neutral conductor and can be used to indicate when the sheath of the mineral insulated cable has corroded to a sufficient extent to permit ingress of moisture therethrough, thereby to provide a warning before the or a core conductor can be seriously affected by the ingress of moisture.
Claim 6
Dependent Claim
23 words
An electric power cable as claimed in claim 6, wherein several mineral insulated cables replace peripherally spaced elements of the concentric neutral conductor.
Claim 7
Dependent Claim
58 words
An electric power cable as claimed in claim 6, in which the concentric neutral conductor comprises a continuous helical lApping of strips, wherein at least one strip of the concentric neutral conductor is replaced by a mineral insulated cable, flattened to a cross-sectional shape approximating to that of a strip without any detrimental effect on its corrosion-detecting performance.
Claim 8
Dependent Claim
163 words
An electric power cable having at least one core comprising an insulated conductor, a concentric neutral conductor comprising metal elements applied about the core or cores, and a plastics sheath, at least a metal element of the neutral conductor and the or a core conductor being of a material selected from the group of materials consisting of aluminum and aluminum-based alloys of high conductivity, wherein a mineral insulated cable, which has a sheath of a material selected from the group of materials consisting of aluminum and aluminum-based alloys and is of a cross-section that is small in comparison with the overall cross-section of the cable, is embedded in the plastics sheath outside of the concentric neutral conductor and can be used to indicate when the sheath of the mineral insulated cable has corroded to a sufficient extent to permit ingress of moisture therethrough, thereby to provide a warning before the or a core conductor can be seriously affected by the ingress of moisture.
Claim 9
Dependent Claim
24 words
An electric power cable as claimed in claim 9, wherein several mineral insulated cables are embedded at peripherally spaced intervals in the plastics sheath.
Claim 10
Dependent Claim
168 words
A protective multiple earth cable installation incorporating an electric power cable having at least one core comprising an insulated conductor, a concentric neutral conductor comprising metal elements applied about the core or cores, and a plastics sheath, at least a metal element of the neutral conductor and the or a core conductor being of a material selected from the group of materials consisting of aluminum and aluminum-based alloys of high conductivity, wherein a mineral insulated cable, which has a sheath of a material selected from the group of materials consisting of aluminum and aluminum-based alloys and is of a cross-section that is small in comparison with the overall cross-section of the cable, replaces at least one element of the concentric neutral conductor and can be used to indicate when the sheath of the mineral insulated cable has corroded to a sufficient extent to permit ingress of moisture therethrough, thereby to provide a warning before the or a core conductor can be seriously affected by the ingress of moisture.
Claim 11
Dependent Claim
35 words
A protective multiple earth cable installation as claimed in claim 11, wherein a conductor of the mineral insulated cable is connected to a detector circuit for indicating the presence of moisture in the power cable.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |