Patent US4042776A successfully refreshed from Google Patents.
US4042776A
Expired / Lapsed
US
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Water tree free power cable
Assignee: Furukawa Electric Co Ltd
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Filing: 1975-08-21
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Granted: 1977-08-16
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Expires: 1995-08-21
Abstract
Abstract A power cable having a plastic electrical insulation which is partially or wholly composed of a plastic compound. The plastic compound containing an inorganic or organic electrolyte which ionizes when dissolved in water, the power cable prevents the deterioration of insulation called "water tree" which has been a fatal drawback of the plastic insulation layers of the conventional plastic insulated cables such as cross-linked polyethylene cables, etc.
Inventors
- 👤 Hironori Matsuba
- 👤 Kazumi Satou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:21
CPC Classifications
H; H01; H01B; H01B7/00; H01B7/02; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/441; H01B7/17; H01B7/28; H01B7/2813; H01B7/282; H01B7/285; Y; Y02; Y02A; Y02A30/00; Y02A30/14
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
66 words
A water tree free electric power cable comprising a conductor enclosed in a sheath of insulation selected from the group consisting of a polyethylene compound, cross-linked polyethylene compound, ethylenepropylene rubber compound and butyl rubber compound, said insulation containing a substantially homogeneously dispersed water soluble strong electrolyte capable of increasing the conductivity of the water in an amount of 10 - 7 to 1 percent by weight.
Claim 2
Dependent Claim
66 words
A water tree free electric power cable comprising a conductor enclosed in a sheath of insulation selected from the group consisting of a polyethylene compound, cross-linked polyethylene compound, ethylenepropylene rubber compound and butyl rubber compound, said insulation containing a substantially homogeneously dispersed water soluble strong electrolyte capable of increasing the conductivity of the water in an amount of 10 - 7 to 1 percent by weight.
Claim 3
Dependent Claim
30 words
The insulated power cable or the accessories thereof as defined in claim 1 wherein said electrolyte is selected from the group consisting of sodium chloride, sodium sulfate or mixtures thereof.
Claim 4
Dependent Claim
29 words
The power cable of claim 1, wherein said strong electrolyte is selected from salts of the alkali metals, alkaline earth metals, copper, ammonia, carboxylic acids and organic sulfonic acids.
Claim 5
Dependent Claim
32 words
The power cable of claim 3, wherein said strong electrolyte is selected from the group consisting of sodium chloride, sodium sulfate, potassium chloride, potassium sulfate, ammonium chloride, cupric sulfate and sodium acetate.
Claim 6
Dependent Claim
33 words
The insulated power cable or accessories thereof defined in claim 1 wherein said insulation or a portion thereof is a thin layer of tape having said strong electrolyte adhered to the surface thereof.
Claim 7
Dependent Claim
21 words
The insulated power cable of claim 1, wherein a layer of semi-conductive material is provided between said conductor and said insulation.
Claim 8
Dependent Claim
58 words
In a method for preventing the deterioration of insulation called water tree in electric power cable the improvement wherein micro-particles of a strong electrolyte which dissolves in water to increase the electric conductivity of the water are added to the insulation material in a ratio to said insulation material between 10 - 7 % and 1% by weight.
Claim 9
Dependent Claim
58 words
In a method for preventing the deterioration of insulation called water tree in electric power cable the improvement wherein micro-particles of a strong electrolyte which dissolves in water to increase the electric conductivity of the water are added to the insulation material in a ratio to said insulation material between 10 - 7 % and 1% by weight.
Claim 10
Dependent Claim
35 words
A method for preventing the deterioration of insulation called water tree as defined in claim 7 wherein said insulation material is selected from the group consisting of polyethylene, cross-linked polyethylene, ethylenepropylene rubber and butyl rubber.
Claim 11
Dependent Claim
68 words
In a process for manufacturing an insulated power cable or the accessories thereof the improvement wherein a strong electrolyte which prevents the deterioration of the insulation called water tree is prearranged to adhere to the surfaces of a pelletized insulation material in the form of micro-particles and said pellets of said insulation material are then molded into insulating material about a conductive member to form a power cable.
Claim 12
Dependent Claim
68 words
In a process for manufacturing an insulated power cable or the accessories thereof the improvement wherein a strong electrolyte which prevents the deterioration of the insulation called water tree is prearranged to adhere to the surfaces of a pelletized insulation material in the form of micro-particles and said pellets of said insulation material are then molded into insulating material about a conductive member to form a power cable.
Claim 13
Dependent Claim
41 words
In a process for manufacturing an insulated power cable or the accessories thereof the improvement wherein a strong electrolyte which prevents the deterioration of a insulation called water tree is added to an additive for said insulation before forming the insulation.
Claim 14
Dependent Claim
41 words
In a process for manufacturing an insulated power cable or the accessories thereof the improvement wherein a strong electrolyte which prevents the deterioration of a insulation called water tree is added to an additive for said insulation before forming the insulation.
Claim 15
Dependent Claim
82 words
In a process for manufacturing an insulated power cable or the accessories thereof the improvement wherein a strong electrolyte which prevents the deterioration of a plastic insulation called water tree is dissolved in a solvent which is capable of dissolving the electrolyte; a solution thus obtained is added to said insulation material, said solvent then being evaporated to leave said electrolyte in the form of micro-particles dispersed in the insulation material; and then said insulation is formed with said plastic insulation material.
Claim 16
Dependent Claim
82 words
In a process for manufacturing an insulated power cable or the accessories thereof the improvement wherein a strong electrolyte which prevents the deterioration of a plastic insulation called water tree is dissolved in a solvent which is capable of dissolving the electrolyte; a solution thus obtained is added to said insulation material, said solvent then being evaporated to leave said electrolyte in the form of micro-particles dispersed in the insulation material; and then said insulation is formed with said plastic insulation material.
References Cited (Backward Citations)
US3663742A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |