US4234754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oil-filled electric cable installations comprising pressurizing oil tanks
Assignee: Balfour Beatty PLC
•
Filing: 1979-02-23
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Granted: 1980-11-18
•
Expires: 1999-02-23
Abstract
Abstract An oil-filled electric cable installation, in which oil when flowing outwardly from the cable to a pressure-maintaining oil tank it passes through a percolating filter, preferably of an active material, to remove particulate and/or dissolved impurities. A one-way return passage bypasses the filter so that maintenance of pressure is not impaired, and if required a high-pressure bypass may be used to protect the filter from unusually high pressures.
Inventors
- 👤 Derek R. Edwards
- 👤 Cyril H. Gosling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:39
CPC Classifications
H; H02; H02G; H02G15/00; H02G15/20; H02G15/26
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
142 words
An oil-filled electric cable installation comprising (i) at least one cable comprising at least one metallic conductor, insulation surrounding the conductor, an enclosing fluid-tight sheath and at least one oil duct extending from end to end of the cable inside the sheath, the cable comprising a plurality of sections defined by stop-joints (ii) oil tanks for maintaining the cable sections filled with oil under pressure and (iii) oil ducts connecting said oil tanks to the stop-joints wherein: at least one said oil duct comprises two passages in parallel; the first passage provides a percolating filter through which oil normally flows when passing from the cable to the tank; and the second passage contains a one-way valve permitting flow of oil from the tank to limit the extent to which the oil pressure in the cable can fall below that in the tank.
Claim 2
Dependent Claim
142 words
An oil-filled electric cable installation comprising (i) at least one cable comprising at least one metallic conductor, insulation surrounding the conductor, an enclosing fluid-tight sheath and at least one oil duct extending from end to end of the cable inside the sheath, the cable comprising a plurality of sections defined by stop-joints (ii) oil tanks for maintaining the cable sections filled with oil under pressure and (iii) oil ducts connecting said oil tanks to the stop-joints wherein: at least one said oil duct comprises two passages in parallel; the first passage provides a percolating filter through which oil normally flows when passing from the cable to the tank; and the second passage contains a one-way valve permitting flow of oil from the tank to limit the extent to which the oil pressure in the cable can fall below that in the tank.
Claim 3
Dependent Claim
32 words
An installation as claimed in claim 1 wherein in that the first passage also includes a non-return valve to prevent any substantial flow of oil through the filter in the reverse direction.
Claim 4
Dependent Claim
36 words
An installation as claimed in claim 1 or claim 2 wherein there is a third passage in parallel with the first and second passages and containing a pressure-relief valve permitting oil to bypass the percolating filter.
Claim 5
Dependent Claim
30 words
An installation as claimed in claim 1 or claim 2 wherein the percolating filter comprises an active material that will selectively adsorb and remove impurities from solution in the oil.
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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) | 1983-11-18 | 1984-05-19 | 1984-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-18 | 1988-05-19 | 1988-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-18 | 1992-05-19 | 1992-11-18 | $7700.00 | Window Closed / Lapsed |