US4053707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for high voltage insulation
Assignee: Raychem Ltd
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Filing: 1976-03-29
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Granted: 1977-10-11
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Expires: 1996-03-29
Abstract
Abstract An insulator having a central portion or stem and one or more sheds is provided with a barrier over at least one of the sheds whereby a substantial improvement in withstanding flashover is obtained yet significant damage to the surface of the insulator is avoided. The barrier comprises a sheet of dielectric material positioned over the upper surface of a shed but spaced away therefrom, the sheet extending radially outwardly to overhang the periphery of the shed. The barrier is furthermore spaced radially away from the central portion or stem of the insulator over at least a substantial part of the inner periphery of the barrier. The barrier may be made of rigid material, for example, constructed from a plurality of sectors but is preferably made from a flexible material so that it can be fitted around an existing conventional insulator. The underside of the barrier is preferably provided with a number of projections for spacing it away from the upper surface of the shed.
Inventors
- 👤 Cyril Harold Arthur Ely
- 👤 Peter John Lambeth
- 👤 John Sidney Thomas Looms
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:37
CPC Classifications
H; H01; H01B; H01B17/00; H01B17/42; Y; Y10; Y10T; Y10T428/00; Y10T428/21; Y10T428/218
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
89 words
A method of improving an insulator having a central portion or stem and one or more sheds comprising the step of putting a barrier of dielectric material over the upper surface of a shed but spaced away therefrom, the barrier extending radially outwardly to overhang the periphery of the shed by at least 5 mm around the whole of the shed, the barrier furthermore being spaced radially from the central portion or stem of the insulator over at least a substantial part of the inner periphery of the barrier.
Claim 2
Independent Claim
89 words
A method of improving an insulator having a central portion or stem and one or more sheds comprising the step of putting a barrier of dielectric material over the upper surface of a shed but spaced away therefrom, the barrier extending radially outwardly to overhang the periphery of the shed by at least 5 mm around the whole of the shed, the barrier furthermore being spaced radially from the central portion or stem of the insulator over at least a substantial part of the inner periphery of the barrier.
Claim 3
Dependent Claim
21 words
A method as claimed in claim 1, wherein the spacing from the central portion or stem is 2 to 20 mm.
Claim 4
Dependent Claim
28 words
A method as claimed in claim 1, wherein at least the upper surface of the shed over which the barrier is put is coated with a track-resistant material.
Claim 5
Dependent Claim
110 words
An insulator having a central portion or stem and one or more sheds extending outwardly therefrom in combination with a discharge barrier comprising a sheet of dielectric material and positioned around the central portion or stem of the insulator above at least one shed, said sheet being spaced away from the upper surface of the shed, said sheet furthermore being arranged to overhang the shed by extending radially outwardly therefrom for a distance of at least 5 mm, said sheet furthermore being dimensioned to leave a gap between the insulator central portion or stem and the sheet over at least a substantial part of the inner periphery of the sheet.
Claim 6
Dependent Claim
110 words
An insulator having a central portion or stem and one or more sheds extending outwardly therefrom in combination with a discharge barrier comprising a sheet of dielectric material and positioned around the central portion or stem of the insulator above at least one shed, said sheet being spaced away from the upper surface of the shed, said sheet furthermore being arranged to overhang the shed by extending radially outwardly therefrom for a distance of at least 5 mm, said sheet furthermore being dimensioned to leave a gap between the insulator central portion or stem and the sheet over at least a substantial part of the inner periphery of the sheet.
Claim 7
Dependent Claim
25 words
The combination as claimed in claim 4, wherein said sheet extends radially outwardly to overhang the shed by a distance of at least 20 mm.
Claim 8
Dependent Claim
24 words
The combination as claimed in claim 4, wherein said gap between the barrier and the central portion or stem is 2 to 20 mm.
Claim 9
Dependent Claim
23 words
The combination as claimed in claim 4, wherein the spacing of the barrier from the upper surface of the shed is substantially uniform.
Claim 10
Dependent Claim
22 words
The combination as claimed in claim 4, wherein a number of small projections are provided on the undersurface of the barrier sheet.
Claim 11
Dependent Claim
25 words
The combination as claimed in claim 8, wherein the projections are arranged on the sheet to be located uniformly around the axis of the insulator.
Claim 12
Dependent Claim
23 words
The combination as claimed in claim 8, wherein adjacent projections are staggered to be at different radii from the centre of the insulator.
Claim 13
Dependent Claim
24 words
The combination as claimed in claim 10, wherein the sheet is secured to the surface of the shed by an adhesive on said projections.
Claim 14
Dependent Claim
17 words
The combination as claimed in claim 4, wherein the upper surface of the barrier sheet is smooth.
Claim 15
Dependent Claim
45 words
The combination as claimed in claim 4, wherein the inner periphery of the barrier is shaped so that this inner periphery comes into contact with the stem of the insulator at a number of points around the periphery although leaving gaps between these contact regions.
Claim 16
Dependent Claim
35 words
The combination as claimed in claim 13, wherein the inner periphery of the barrier is formed as a series of inwardly-directed projecting tongues, the tongues being narrow in width compared with the gaps between them.
Claim 17
Dependent Claim
16 words
The combination as claimed in claim 14, wherein the barrier has four to twelve inwardly-directed tongues.
Claim 18
Dependent Claim
27 words
The combination as claimed in claim 14, wherein said inwardly-extending tongues extend upwardly adjacent the stem or body of the insulator to locate under the next shed.
Claim 19
Dependent Claim
29 words
The combination as claimed in claim 14, wherein a spacer is provided around the insulator stem or body, the spacer being shaped to engage and locate said inwardly-directed tongues.
Claim 20
Dependent Claim
63 words
The combination as claimed in claim 4 and having a spacer around the insulator stem or body engaging the inner periphery of said barrier at a plurality of points around that periphery so that a gap is left between the inner periphery of the barrier and the spacer or insulator body or stem over at least a substantial portion of the inner periphery.
Claim 21
Dependent Claim
30 words
The combination as claimed in claim 4, wherein at least one spacing element is provided to space the lower surface of the sheet from the upper surface of the shed.
Claim 22
Dependent Claim
23 words
The combination as claimed in claim 19, wherein the spacing element is integral with a spacer provided around the insulator stem or body.
Claim 23
Dependent Claim
22 words
The combination as claimed in claim 4, wherein the upper surface of the shed is provided with a number of small projections.
Claim 24
Dependent Claim
30 words
The combination as claimed in claim 4, wherein the barrier is sufficiently flexible that it can be put around an existing insulator of porcelain or glass or other conventional material.
Claim 25
Dependent Claim
45 words
The combination as claimed in claim 22, wherein the discharge barrier is formed of a single sheet of material divided radially from its inner to its outer periphery, so that the sheet can be put around the insulator and joined where it was radially divided.
Claim 26
Dependent Claim
26 words
The combination as claimed in claim 23, wherein the two edges of the sheet, after being put around the insulator, are secured together with an adhesive.
Claim 27
Dependent Claim
30 words
The combination as claimed in claim 23, wherein the two edges of the sheet, after being put around the insulator, overlap and are secured together by fasteners of dielectric material.
Claim 28
Dependent Claim
16 words
The combination as claimed in claim 25, wherein said fasteners are nuts and bolts or rivets.
Claim 29
Dependent Claim
17 words
The combination as claimed in claim 25, wherein said fasteners are peg and hole push fit fasteners.
Claim 30
Dependent Claim
32 words
The combination as claimed in claim 23, wherein the two portions of the sheet to be joined are secured with their edges abutting, by joining each portion separately to a jointing element.
Claim 31
Dependent Claim
26 words
The combination as claimed in claim 23, wherein the portions of the sheet to be joined overlap and are shaped resiliently to interlock with one another.
Claim 32
Dependent Claim
32 words
The combination as claimed in claim 23, wherein the portions of the sheet to be joined overlap and are secured together by elements engaging in slots or grooves in the overlapping portions.
Claim 33
Dependent Claim
18 words
The combination as claimed in claim 23, wherein a dielectric filler material is put between the jointed parts.
Claim 34
Dependent Claim
32 words
The combination as claimed in claim 22, wherein said sheet is shaped so that it can be put around the insulator body or stem as a helix having two or more turns.
Claim 35
Dependent Claim
17 words
The combination as claimed in claim 32, wherein adjacent turns of the helix are secured in contact.
Claim 36
Dependent Claim
16 words
The combination as claimed in claim 32, wherein adjacent turns of the helix are spaced apart.
Claim 37
Dependent Claim
14 words
The combination as claimed in claim 22, wherein said sheet has radial stiffening ribs.
Claim 38
Dependent Claim
15 words
The combination as claimed in claim 22, wherein said sheet has a peripheral stiffening rib.
Claim 39
Dependent Claim
24 words
The insulator of claim 4 wherein said shed or sheds is made from a flexible polymeric material and said barrier is formed integrally therewith.
Claim 40
Dependent Claim
23 words
The insulator of claim 4 wherein said shed or sheds is made from a flexible polymeric material and said barrier is fitted thereto.
Claim 41
Dependent Claim
48 words
A shed for an electrical insulator, comprising a flexible polymeric shed and a barrier of dielectric material, said barrier being spaced away from the upper surface of said flexible polymeric shed and having an inner periphery of greater diameter than the inner periphery of said flexible polymeric shed.
Claim 42
Dependent Claim
48 words
A shed for an electrical insulator, comprising a flexible polymeric shed and a barrier of dielectric material, said barrier being spaced away from the upper surface of said flexible polymeric shed and having an inner periphery of greater diameter than the inner periphery of said flexible polymeric shed.
Claim 43
Dependent Claim
18 words
The shed of claim 39 wherein said barrier of dielectric material is integral with said flexible polymeric shed.
Claim 44
Dependent Claim
73 words
An annular barrier for fitting on a shed and about a stem of an electrical insulator, comprising an annular barrier sheet of flexible, dielectric, anti-tracking material, said annular barrier sheet having a substantially radial division, means for joining said barrier sheet to close said substantially radial division and a plurality of projections on one side of said annular barrier sheet to space said annular barrier sheet from the upper surface of the shed.
Claim 45
Dependent Claim
73 words
An annular barrier for fitting on a shed and about a stem of an electrical insulator, comprising an annular barrier sheet of flexible, dielectric, anti-tracking material, said annular barrier sheet having a substantially radial division, means for joining said barrier sheet to close said substantially radial division and a plurality of projections on one side of said annular barrier sheet to space said annular barrier sheet from the upper surface of the shed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-10 | 1981-04-11 | 1981-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-10 | 1985-04-11 | 1985-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-10 | 1989-04-11 | 1989-10-11 | $7700.00 | Window Closed / Lapsed |