US3621110A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field impregnated extra high voltage cable system
Assignee: General Cable Corp
•
Filing: 1969-04-01
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Granted: 1971-11-16
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Expires: 1989-04-01
Abstract
Abstract This electric cable uses a polymeric insulation in place of impregnated paper insulation to make possible underground transmission lines for high voltage. The cable is constructed for impregnation in the field and is filled, usually with oil, after installation in a pipe. The cable insulation is a fibrous paperlike sheet material of high-density polyethylene. Low friction of the insulation, when dry, permits bending around smaller spools for shipping. The cable is free of cellulose material, or other substances that have a sponge effect when exposed to moisture, so that no high-temperature drying is required in the field prior to impregnating the cable.
Inventors
- 👤 Martin H Mcgrath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:59
CPC Classifications
H; H01; H01B; H01B13/00; H01B13/30; H01B7/00; H01B7/17; H01B7/28; H01B7/282; H01B7/2825; H01B9/00; H01B9/06; H01B9/0611; H02; H02G; H02G9/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
163 words
A high-voltage electrical cable for installation in an unfilled state and subsequent fluid filling of the cable after installation including, in combination, a conductor, synthetic polymeric insulation of fibrous paperlike structure that swells when exposed to contact with insulating oil and that is insensitive to moisture and from which moisture can be expelled by a dry atmosphere at substantially room temperature, the insulation material itself having a moisture content less than about 0.1 percent and being free of oil impregnation, and overlapping conducting tapes wrapped around the outside of the insulation and constituting the insulation shielding of the cable and in contact with the insulation and having a long lay with a helical pitch greater than about 2 1/2 times the cable diameter to increase the length of each convolution of the shielding tape and thereby reduce the stretch per unit of length of the shielding tape to accommodate swelling of the insulation when the cable is installed and filled with insulating oil.
Claim 2
Dependent Claim
163 words
A high-voltage electrical cable for installation in an unfilled state and subsequent fluid filling of the cable after installation including, in combination, a conductor, synthetic polymeric insulation of fibrous paperlike structure that swells when exposed to contact with insulating oil and that is insensitive to moisture and from which moisture can be expelled by a dry atmosphere at substantially room temperature, the insulation material itself having a moisture content less than about 0.1 percent and being free of oil impregnation, and overlapping conducting tapes wrapped around the outside of the insulation and constituting the insulation shielding of the cable and in contact with the insulation and having a long lay with a helical pitch greater than about 2 1/2 times the cable diameter to increase the length of each convolution of the shielding tape and thereby reduce the stretch per unit of length of the shielding tape to accommodate swelling of the insulation when the cable is installed and filled with insulating oil.
Claim 3
Dependent Claim
29 words
The high-voltage electrical cable described in claim 1 characterized by the insulation shielding and all of the space enclosed within the insulation shielding being free of any cellulose material.
Claim 4
Dependent Claim
52 words
The high-voltage electrical cable described in claim 1 characterized by the insulation being high-density fibrous polyethylene comprising webs of randomly arranged, highly dispersed, continuous filament fibers bonded primarily at filament crossovers, and said insulation being successive helical layers of tape over one another, the insulation shielding assembly fitting closely around the cable.
Claim 5
Dependent Claim
46 words
The high-voltage electrical cable described in claim 3 characterized by the insulation shielding assembly including a plurality of semiconducting plastic tapes in overlapping helixes, and skid wires wrapped around the tapes of the insulation shielding in contact with the insulation shielding and having a long lay.
References Cited (Backward Citations)
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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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |