CA1049630A - Sealing capacitor fill holes - Google Patents
Sealing capacitor fill holesInfo
- Publication number
- CA1049630A CA1049630A CA237,483A CA237483A CA1049630A CA 1049630 A CA1049630 A CA 1049630A CA 237483 A CA237483 A CA 237483A CA 1049630 A CA1049630 A CA 1049630A
- Authority
- CA
- Canada
- Prior art keywords
- plug
- extension
- wall
- fill hole
- hole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT OF THE DISCLOSURE
In a capacitor of the type having a liquid dielectric impregnated capacitor element mounted in a metal can, electrical terminals passing through openings into the can, and a fill hole through a wall of the can for addition therethrough of liquid impregnant, that improvement comprising a sleeve-like, integral extension of the wall surrounding the fill hole and coaxial there-with, the extension being of circular cross-section, and a solid, resilient plug inserted in the hole and extending coaxially there-with, the unstressed outside diameter of the plug being larger than the corresponding inside diameter of the extension whereby the plug when inserted in the hole is in compression, one end of the plug extending outwardly of the wall a distance sufficient so that downward manual pressure on the plug will cause it to bend slightly and thus resist being pushed down through the extension, the other end of the plug extending into the can beyond the extension to provide a reexpanded portion which resists upward withdrawal of the plug.
In a capacitor of the type having a liquid dielectric impregnated capacitor element mounted in a metal can, electrical terminals passing through openings into the can, and a fill hole through a wall of the can for addition therethrough of liquid impregnant, that improvement comprising a sleeve-like, integral extension of the wall surrounding the fill hole and coaxial there-with, the extension being of circular cross-section, and a solid, resilient plug inserted in the hole and extending coaxially there-with, the unstressed outside diameter of the plug being larger than the corresponding inside diameter of the extension whereby the plug when inserted in the hole is in compression, one end of the plug extending outwardly of the wall a distance sufficient so that downward manual pressure on the plug will cause it to bend slightly and thus resist being pushed down through the extension, the other end of the plug extending into the can beyond the extension to provide a reexpanded portion which resists upward withdrawal of the plug.
Description
3~4963~
BAcKGRo-uND ~ Q~
This invention rela-tes to liquid dielectric impregnated capacitors.
Typically, the outer can of such a capacitor has a fill hole through which dielectric liquid is added after the capacitor element has been mounted in the can. The fill hole must then be sealed. In Dubilier United States Patent No. 3,258,666 the fill hole is sealed with solder. Thomas United States Patent No.
1,497,415 shows a molded oil filled condenser with a threaded plug in a fill hole. In Rayno United States Patent No. 3,389,311 the dielectric liquid is added through the electrode lead openings in the can, without a separate fill hole.
SUMMARY OF THE INVENTION
The invention provides a highly effective, reliable, long-lasting fill hole seal, which can be inexpensively and auto-matically installed. The disadvantages of a solder seal (e.g., contamination of the capacitor by soldering fluxes, and latent defects such as bubbles caused by overheating during the soldering process) are avoided. The seal is applicable to cans of a variety of metals, even including aluminum. In the case of pitch potted, halogenated hydrocarbon dielectric capacitors, contamination of the dielectric by the pitch during operating is minimized.
In general the invention features a capacitor of the type having a liquid dielectric impregnated capacitor element mounted in a metal can, electrical terminals passing through openings into the can, and a fill hole through a wall of the can for addition there-through of liquid impregnant, that improvement comprising a sleeve-like, integral extension of the wall surrounding the fill hole and coaxial therewith, the extension being of circular cross-section, and a solid, resilient plug inserted in the hole and extending coaxially therewith, the unstressed outside diameter of the plug being larger than the corrésponding inside diameter oE the .. . . . .
: , ' ' .
1~4~631LI~
extension whereby the plug when inserted in the hole is in compression, one end of the plug extending ou-twardly of the wall a distance sufficien-t so that downward manual pressure on -the plug will cause it to bend slightly and thus resist being pushed down through the extension, -the other end of the plug extending into the can beyond the extension to provide a reexpanded portion which resists upward withdrawal of the plug.
In preferred embodiments a silicone plug extends 0.031"
- 0.005" outwardly beyond the outer surface of the wall; the unstressed outside diameter of the plug is sufficiently larger than the corresponding inside diameter of the extension to cause compression of the plug by at least 15~; the extension has a flared portion in the plane of the wall, and a cylindrical portion extending inwardly from the wall; the cross-sectional area of the plug is less thant 0.~2 square inch; and the plug extends across the plane of a paper insulating strip extending along the undersurface ~
of the wall, and the strip is cut away adjacent the plug so that ~ -the plug is free-standing and contacts only the extension.
Other advantages and features of the invention will be 20 apparent from the description and drawings herein of a preferred ;~
embodiment thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a capacitor embodying the invention;
Fig. 2 is a front elevation, partially broken away, of ~ -the capacitor of Fig. l;
Fig. 3 is a sectional view taken along 303 of Fig. 2;
Fig. 4 is a fragmentary sectional view taken along 4-4 of Fig. 3; and Fig. 5 is a fragmentary, semi-schematic sectional view ~ -showing installation of a plug in a fill hole.
."
s) , ~
, ; :
, : , . , ~ .
., , . , . . . ., ~ , 10~9gj30 DESCRIPTION OF ~ E PREFERRED EMsoDIMENT
~ . ~
Referring to the drawings, capacitor 10 has an outer aluminum can 12 con-taining a conventional capacitor element 14 having alternate dielectric and electrically conductive layers, and a halogenated hydrocarbon dielectric liquid. Leads 16 connect the capacitor conductors to terminals 18 rr~oun-ted in cover 20 of the can and sealed thereto by silicone bushings 22. Paper insulating strip 24, supported by the terminals, extends along the under-surface of cover 20 just below the bushings.
Collar 30, integral with can cover 20, extends down from the cover to define a hole 32 through which the capacitor is filled with the liquid dielectric. The collar is flared at 34 in the plane of the cover and otherwise has a smooth surfaced cylindrical wall 36 which extends 0.038" below the cover.
Resilient, cylindrical, silicone plug 38 serves as a seal for fill hole 32, and has an outside diameter (0.125" in the example shown) sufficiently larger than the inside diameter of collar portions 36 (0.100" in the example shown) to cause compres-sion of the plug by at least 15% (preferably 20~
To ensure the integrity of the fill hole seal, plug 38 has a portion 40 extending sufficiently below collar 30 to prevent, by reexpansion of that plug portion, upward withdrawal of the plug, and a portion 42 extending above the plane of cover 20 sufficiently so that downward finger pressure on the plug causes portion 42 to bend slightly and thus resist being pushed down through the collar.
However, plug portion 42 should be short enough to prevent the plug from being damaged by manipulation. In the example, shown portion 42 extends 0.031" t 0.005" above the outer surface of cover 20, a critical dimension. Further, plug portion 40 should be short 30 enough to avoid contact with the capacitor element and thus the application of potentially seal-wéakening stresses to the plug.
To further avoid such stresses, insulating strip 24 is cut away at ' ~ .
`
.
: , ' ' ` ' ' ~ , ~4~36;:~
44 around the plug, which thus contacts only collar 30.
Capacitor 10 is assembled by plaeing element 14 in the can, attaching the cover, and adding -the liquid dielectric through hole 32. Silicone rod 46, compressed in quide 50 to slightly less than the inside diameter of collar 30, is forced into the fill hole while being held in place by pressure pads 52. The guide is then withdrawn to allow eutters 54 to engage the rod, severing the silicone to leave plug 38.
The very small cross-sectional area of plug 38 (preferably always less than 0.02 square inch) minimizes any contamination of the dieleetrie liquid by the piteh potting typieally used for ; ballast eapacitors and typically drawn into sueh eapaeitors by solution in the halogenated hydrocarbon upon temperature fluctuation during operation.
Other embodiments (e.g., the use of non-setting, resilient :
material other than silicone for plug 38; or the use of a metal other than aluminum for can 12, ete.) are within the following :
claims. ~ ~
~ ~, :: , ' '; '' ' ' ' ~';'"~
~ . ..
~: ,
BAcKGRo-uND ~ Q~
This invention rela-tes to liquid dielectric impregnated capacitors.
Typically, the outer can of such a capacitor has a fill hole through which dielectric liquid is added after the capacitor element has been mounted in the can. The fill hole must then be sealed. In Dubilier United States Patent No. 3,258,666 the fill hole is sealed with solder. Thomas United States Patent No.
1,497,415 shows a molded oil filled condenser with a threaded plug in a fill hole. In Rayno United States Patent No. 3,389,311 the dielectric liquid is added through the electrode lead openings in the can, without a separate fill hole.
SUMMARY OF THE INVENTION
The invention provides a highly effective, reliable, long-lasting fill hole seal, which can be inexpensively and auto-matically installed. The disadvantages of a solder seal (e.g., contamination of the capacitor by soldering fluxes, and latent defects such as bubbles caused by overheating during the soldering process) are avoided. The seal is applicable to cans of a variety of metals, even including aluminum. In the case of pitch potted, halogenated hydrocarbon dielectric capacitors, contamination of the dielectric by the pitch during operating is minimized.
In general the invention features a capacitor of the type having a liquid dielectric impregnated capacitor element mounted in a metal can, electrical terminals passing through openings into the can, and a fill hole through a wall of the can for addition there-through of liquid impregnant, that improvement comprising a sleeve-like, integral extension of the wall surrounding the fill hole and coaxial therewith, the extension being of circular cross-section, and a solid, resilient plug inserted in the hole and extending coaxially therewith, the unstressed outside diameter of the plug being larger than the corrésponding inside diameter oE the .. . . . .
: , ' ' .
1~4~631LI~
extension whereby the plug when inserted in the hole is in compression, one end of the plug extending ou-twardly of the wall a distance sufficien-t so that downward manual pressure on -the plug will cause it to bend slightly and thus resist being pushed down through the extension, -the other end of the plug extending into the can beyond the extension to provide a reexpanded portion which resists upward withdrawal of the plug.
In preferred embodiments a silicone plug extends 0.031"
- 0.005" outwardly beyond the outer surface of the wall; the unstressed outside diameter of the plug is sufficiently larger than the corresponding inside diameter of the extension to cause compression of the plug by at least 15~; the extension has a flared portion in the plane of the wall, and a cylindrical portion extending inwardly from the wall; the cross-sectional area of the plug is less thant 0.~2 square inch; and the plug extends across the plane of a paper insulating strip extending along the undersurface ~
of the wall, and the strip is cut away adjacent the plug so that ~ -the plug is free-standing and contacts only the extension.
Other advantages and features of the invention will be 20 apparent from the description and drawings herein of a preferred ;~
embodiment thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a capacitor embodying the invention;
Fig. 2 is a front elevation, partially broken away, of ~ -the capacitor of Fig. l;
Fig. 3 is a sectional view taken along 303 of Fig. 2;
Fig. 4 is a fragmentary sectional view taken along 4-4 of Fig. 3; and Fig. 5 is a fragmentary, semi-schematic sectional view ~ -showing installation of a plug in a fill hole.
."
s) , ~
, ; :
, : , . , ~ .
., , . , . . . ., ~ , 10~9gj30 DESCRIPTION OF ~ E PREFERRED EMsoDIMENT
~ . ~
Referring to the drawings, capacitor 10 has an outer aluminum can 12 con-taining a conventional capacitor element 14 having alternate dielectric and electrically conductive layers, and a halogenated hydrocarbon dielectric liquid. Leads 16 connect the capacitor conductors to terminals 18 rr~oun-ted in cover 20 of the can and sealed thereto by silicone bushings 22. Paper insulating strip 24, supported by the terminals, extends along the under-surface of cover 20 just below the bushings.
Collar 30, integral with can cover 20, extends down from the cover to define a hole 32 through which the capacitor is filled with the liquid dielectric. The collar is flared at 34 in the plane of the cover and otherwise has a smooth surfaced cylindrical wall 36 which extends 0.038" below the cover.
Resilient, cylindrical, silicone plug 38 serves as a seal for fill hole 32, and has an outside diameter (0.125" in the example shown) sufficiently larger than the inside diameter of collar portions 36 (0.100" in the example shown) to cause compres-sion of the plug by at least 15% (preferably 20~
To ensure the integrity of the fill hole seal, plug 38 has a portion 40 extending sufficiently below collar 30 to prevent, by reexpansion of that plug portion, upward withdrawal of the plug, and a portion 42 extending above the plane of cover 20 sufficiently so that downward finger pressure on the plug causes portion 42 to bend slightly and thus resist being pushed down through the collar.
However, plug portion 42 should be short enough to prevent the plug from being damaged by manipulation. In the example, shown portion 42 extends 0.031" t 0.005" above the outer surface of cover 20, a critical dimension. Further, plug portion 40 should be short 30 enough to avoid contact with the capacitor element and thus the application of potentially seal-wéakening stresses to the plug.
To further avoid such stresses, insulating strip 24 is cut away at ' ~ .
`
.
: , ' ' ` ' ' ~ , ~4~36;:~
44 around the plug, which thus contacts only collar 30.
Capacitor 10 is assembled by plaeing element 14 in the can, attaching the cover, and adding -the liquid dielectric through hole 32. Silicone rod 46, compressed in quide 50 to slightly less than the inside diameter of collar 30, is forced into the fill hole while being held in place by pressure pads 52. The guide is then withdrawn to allow eutters 54 to engage the rod, severing the silicone to leave plug 38.
The very small cross-sectional area of plug 38 (preferably always less than 0.02 square inch) minimizes any contamination of the dieleetrie liquid by the piteh potting typieally used for ; ballast eapacitors and typically drawn into sueh eapaeitors by solution in the halogenated hydrocarbon upon temperature fluctuation during operation.
Other embodiments (e.g., the use of non-setting, resilient :
material other than silicone for plug 38; or the use of a metal other than aluminum for can 12, ete.) are within the following :
claims. ~ ~
~ ~, :: , ' '; '' ' ' ' ~';'"~
~ . ..
~: ,
Claims (7)
1. In a capacitor of the type having a liquid di-electric impregnated capacitor element mounted in a metal can, electrical leads passing through lead openings into said can, and a fill hole through a wall of said can for addition therethrough of liquid impregnant, an insulating strip extending along the undersurface of said wall, said fill hole being separate from and in addition to said lead openings, that improvement compris-ing a sleeve-like, integral extension of said wall surrounding said fill hole and coaxial therewith, said extension being of circular cross-section, and a solid resilient plug located in said hole and extending coaxially therewith, the unstressed out-side diameter of said plug being larger than the corresponding inside diameter of said extension whereby said plug is in com-pression in said hole, one end of said plug extending outwardly of said wall a distance sufficient so that manual pressure on said plug in the direction inwardly of the can will cause it to bend slightly and thus resist being pushed down through said extension, the other end of said plug extending into said can bey-ond said extension, to provide a re-expanded portion which re-sists upward withdrawal of said plug, said insulating strip being cut away adjacent said plug, said plug being free-standing and spaced from said capacitor element, contacting only said extension.
2. The improvement of claim 1, wherein said plug extends 0.031" + 0.005" outwardly beyond the outer surface of said wall.
3. The improvement of claim 1, wherein said unstres-sed outside diameter of said plug is sufficiently larger than said corresponding inside diameter of said extension to cause com-pression of said plug by at least 15%.
4. The improvement of any of claims 1 to 3, where-in the cross-sectional area of said plug is less than 0.02 square inch.
5. The improvement of any of claims 1 to 3, wherein said plug is of silicone.
6. The improvement of claim 1 wherein said exten-sion has a flared portion in the plane of said wall, and a cylin-drical portion extending inwardly from said wall.
7. The process of sealing a liquid dielectric im-pregnant fill hole in a capacitor having a capacitor element mounted in a metal can through a wall of which said fill hole passes, comprising the steps of compressing a resilient rod in a guide so that the compressed outside diameter of said rod is similar than the in-side diameter of said fill hole, aligning said guide and rod axially with said fill hole, forcing an integral end portion of said rod through said guide to form a plug in said fill hole, and cutting off said plug from the remainder of said rod to leave said plug in said fill hole.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US51662974A | 1974-10-21 | 1974-10-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1049630A true CA1049630A (en) | 1979-02-27 |
Family
ID=24056432
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA237,483A Expired CA1049630A (en) | 1974-10-21 | 1975-10-10 | Sealing capacitor fill holes |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1049630A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4992910A (en) * | 1989-11-06 | 1991-02-12 | The Evans Findings Company, Inc. | Electrical component package |
-
1975
- 1975-10-10 CA CA237,483A patent/CA1049630A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4992910A (en) * | 1989-11-06 | 1991-02-12 | The Evans Findings Company, Inc. | Electrical component package |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4314213A (en) | Through-type capacitor | |
| US4420791A (en) | Dielectric fluid | |
| US4768129A (en) | Through type twin capacitor | |
| US3555370A (en) | Electrolytic capacitors having improved seal and vent | |
| US3389311A (en) | Sealed capacitor and method of sealing thereof | |
| WO1994003915A2 (en) | Solderless cartridge fuse | |
| US4633367A (en) | Pressure sensitive fault current interrupter for metallized film capacitors with oil impregnate | |
| CA1049630A (en) | Sealing capacitor fill holes | |
| EP0389937A2 (en) | Means for converting a lamp with a screw-type base into a lamp with a bi-pin base | |
| US3015050A (en) | Capacitor structure | |
| US2963771A (en) | Methods of making electrical capacitors | |
| US3289051A (en) | Sealed electrical apparatus | |
| US2805372A (en) | Condenser | |
| US3904939A (en) | Capacitor case seal and venting means | |
| US2129089A (en) | Electrolytic condenser | |
| CN101364481B (en) | High-voltage capacitor having rectifying apparatus | |
| US3155876A (en) | Electrical capacitor protective arrangement | |
| US4754195A (en) | High-pressure discharge lamp, and method of its manufacture | |
| US3256382A (en) | Seal constructions for electrical devices | |
| US3735480A (en) | Polytetrafluoroethylene end plug seal for electrolytic capacitors | |
| US3398340A (en) | High-voltage electrical capacitor | |
| US5047744A (en) | High voltage fluid filled transformer | |
| US3299333A (en) | Electrical capacitor | |
| GB611900A (en) | Improvements in or relating to electrical condensers | |
| CN111146723A (en) | Gis |