US1871356A - Bushing structure - Google Patents

Description

9, 1932- A H. BAKKEN BUSHING STRUCTURE Filed July 5, 1929 R O T N E V m Andre w H. Ba/c/cen.

II II A i I I u'!'f'l'lfl'l ATIZORNEY Patented Aug. 9, 1932 UNITED STATES PATENT? OFFICE ANDREW H. BAKKEN, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC dz HANUFACTUBIN COMPANY, A CORPORATION OF PENNSYLVANIA BUSHING STRUCTURE Application tiled July 5,

My invention relates to high-voltage devices and particularly to bushings of the condenser type.

One object of my invention is to provide a device of the above-indicated character that shall be simple and durable in con-- struction, economical to manufacture and effective in its operation.

Another object of my invention is to provide a high-voltage structure embodying dielectric and metal elements for attachment to each other in a particular relation, wherein cements and other bonding media, having finite life shorter than that of the structure, and other attaching means of usual character, such as screws, bolts and the like, with the attendant disadvantage thereof, shall be replaced by a means for securing the dielectric and metal elements to each other in a simple expeditious manner, free of the faults of features formerly used in the place of such means. 7

Another object of my invention is to rovide a high-voltage structure inclu ing means for securing metal and dielectric members to each other that shall conserve more space, comprise fewer arts, have longer life and be more relia le than similar structures heretofore employed.

A further object of-my invention is to provide a high-Volta e structure, as indicated above, that shall e less dependent upon the uality of the materials employed and the s ill of the workmanship required than former similar structures, thereby facilitating the manufacture and assembly of the device and rendering it an improvement in various aspects in the art to which it relates.

In high-voltage electrical apparatus, the quality, structure and relation of parts are usually of great importance where the. parts are subject to the influence of oil, air, moisture, corona and other features.

Particularly where dielectric and metal elements are joined to ach other and subject to electrical stresses, the joining means are often sources of trouble and expense, and sometimes the weak features result in breakdown, part replacements and other objectionable features.

1829. Serial H0. 378,078.

. I'n high-voltage bushings of the condenser type, it is necessary to support the bushings intermediate the ends thereof, and it is to these intermediate supports and the method of securing them to the bushings to which my invention more particularly relates.

Where a condenser bushing is disposed in versely afiected, unless a structure of very highrade materials and workmanship and of re atively expensive and difficult manufacture and assembly is provided.

In practicin' my invention, I "rovidea condenser'bushlng or other dielectric element and a metal support therefor that are so joined as to avoid the objections to the use of bonding materials and other attachin means heretofore employed, substantially a elements extraneous to the bushing and its support being eliminated and the bushing and its support having mutual holding relation.

The single figure of the accompanying drawing is a view partially in longitudinalside elevation and partially in longitudinal section, of a condenser bushing, constructed in accordance with my invention.

The device comprises, in eneral, a condenser bushing 2, a throng conductor 3 therefor, an upper clamping nut 4, a lower contact-member support 5 and a main bushing ground support 6.

The bushing 2 is in the form of an elongated-tube of dielectric material, preferably wound of fibrous sheet material, such as paper, impregnated with a binder, and having concentric conducting condenser elements or cylinders 8 embedded therein. The latter are preferably ositioned during the winding operation and wardly of shorter lengths and greater diamp are successively ou mo eter to prevent equal or other voltage-gm while the bushing is still in the winding machine or lathe-like apparatus for building up its dielectric and conducting layers.

The conductor 3 is preferably of solid metal, such as cop er, although it may be of tubular form, an is provided, at its u per end, with exterior screw-threads 12 an at its lower end, with the member for supportin a stationary contact member (not shown? of a circuit interrupter. The member 5 is preferably welded to the conductor 3 and may be replaced by'a member for receiving a transformer lead. Also, if the conductor be tubular, the member 5 may be omitted lead be brought from a transformer or other apparatus to the lower end of the bushing 2 and through the bushing.

While the structures at .the ends of the bushing are not germane to this invention and may be variously modified, themember 5, as-shown, is corrugated on its upper sur-. face to provide better holding relation to the lower end surface o,f* the bushing, and the nut 4 is provided for cooperation with the screw-threaded portion 12 of the conductor 3 to draw the nut 4 and the member 5 longitudinally together, thereby providing tight assembly of these parts relative to the bushing. 1 V

The main bushing support 6 is preferably of metal, such as brass, steel'or copper, and includes a one-piece tubular portion or sleeve 14 capable of having'annular projections or flanges 15 pressed orrolled into the proove portions of the bushing 2 and into contact with the outer conducting cylinder 8. There are preferably two of the flanges longitudinally oflset relatively adjacent to one end of the sleeve 14 and a portion 17 adjacent to the other end of thesleeve that is rolled against the bushing which, however, is preferably not grooved opposite the portion 17 as it is opposite the flanges 15.

The sleeve 6 is preferably exteriorly screwthreaded between the portions '15 and 17 for the reception and adjustment of a laterallyoutwardly projecting flange nut or collar 18 which-is secured to the-sleeve '6, as by a weld or solder joint 20, after adjustment.

Spanner wrench slots 22 may be provided in the supporting flan e 18 for adjusting it and openings 23 provi ed thereon for securing it to the cover of a circuit-interrupter, a transformer or other apparatus tank.

and a flexible conducting cable or The sleeve 6 is preferably constructed to initially have a close sliding fit over the bushing 2.

With the outer cylindrical surface of. the bushing provided with a relatively-thin or surperficial film of a binder, such as shellac, the sleeve 6 is slidably moved to its position shown, after which the flanges 15 and the portion 17 are rolled against the bushing to rovide radial pressure between the bushing and the sleeve. By the lateral'interfitting relation of the flanges 15 in the grooves 10, the support 6 and the bushin 2 are interlocked against longitudinal reitive movement.

shellac or other binder between the sleeve and the bushing acts as a further seal against the admission of air, oil and moisture, and by its thinness and protection by the bushing and the sleeve, it is not subject to deterioration, or of causing trouble, if it be slightly affected by electrical stresses, air, oil, moisture, or other factors. 7

In former practice, it was usual to provide a larger element in the place of the sleeve 6 because of the necessity of utilizing a relatively thick cylinder of cement or other material between the sleeve and bushing, which material has a finite life, under the attendant conditions, of shorter duration than the other elements of the combination, resulting in breakdowns, replacements and other expense and trouble. Also, in former practice, the support corresponding to the main bushing support 6, was materially more complicated and expensive.

The reduction of materials and the saving of space not only render the structure neater, more. compact and more effective from mechanical and manufacturing standpoints, but, by reason of the high voltages employed in association with devices of this character, also inure to the betterment of its electrical effectiveness in reducing losses, in preventing interruption of service and in being a general improvement in other ways.

Also, as distinguished from former devices of this character, the assembled structure is more solid mechanically, and free from looseness caused by temperature changes and oil saturation.

While I have shown and described a particular form of my invention,'changes may be effected therein Without departing from the spirit and scope thereof, as set forth in the appended claims.

I I claim as my invention:

1. In combination, a bushing, comprising alternately-disposed dielectric and conducting condenser elements, and a metal bushing support including a one-piece portion of substantially closed-loop shape having a flange surrounding, and held relative to an outer dielectric element of,;a gruove insthe bushing The extremely thin or superficial film of under radial pressure in engagement with a conducting condenser element of the bushing. 2. In combination, a condenser bushing having cylindrical outer-surface dielectric portions and an annular outer-surface groove portion between said surface portions and abushing sup ort including a cylindrical sleeve surroun ing the bushing and having an inwardly bent annular flange engaging a conducting condenser element in said groove.

3. In combination, a condenser bushin having a cylindrical outer-surface dielectric portion and a plurality of longitudinallyspaced annular outer-surface groove portions therein, and'fi bushing support including a cylindrical metal sleeve surrounding the bushing and having an annular flan e in each of said grooves in engagement wit one of the conducting condenser elements, and an outwardly-projecting portion longitudinally ofi'set from said flanges.

4. In combination, a condenser bushing comprising telescoped dielectric and conducting cylinders including a cylindrical outersurface dielectric portion and a plurality of longitudinally-spaced annular groove portions of arcuate transverse contour in said outer-surface portion and a bushing sup ort including a cylindrical-sleeve surroun ing the bushing and having inner annular flanges in and conforming to, said arcuate rooves, in engagement with one of said conucting cylinders adjacent to one end of the sleeve, and an outwardly-projecting portion at an intermediate portion of said sleeve, the latter having a portion adjacent to its other end under radial pressure relative to the bushing, and a superficial-film binder between the bushing and said sleeve.

5. In combination, a condenser bushing including a dielectric cylinder and a conducting cylinder intermediate the inner and outer surfaces of the dielectric cylinder, the latter havingan outer surface annular groove exposing said conducting cylinder, and a bushmg support including a metal cylindrical sleeve surrounding the bushing and having an inwardly bent annular flange intermediate its ends in contact with said conducting cylinder in said groove.

6. In, combination, a condenser bushing comprising radially-oppositely spaced dielectric and conducting cylinders including longitudinally-spaced outer dielectric cylindrical portions roviding a peripheral groove in the bushing with the outer surface of a conducting cylinder at the bottom of said groove, and a metal support surrounding an intermediate portion of the bushing and having an inwardl -bent annular flange engaging said sur ace in said groove.

7. In combination, a condenser bushing comprising radially-oppositel spaced dielectric and conducting cylin ers including ANDREW H. BAKKEN.

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