US2321793A - Bushing insulator - Google Patents

Description

T. F. BRANDT BUSHING INSULATOR `lune 15, 1943.

Original Filed Dec. 50, 1959 THOMAS I.' BRANBT (Ittorneg z am@ Patented June 15, 1943 BUSHING INSULATOR Thomas F. Brandt, Barbcrton, Ohio, assignor to The Ohio Brass Company, Mansfield, Ohio, a corporation of New Jersey Original application December 30, 1939, Serial No.

Divided and this application March 7, 1942, Serial No. 433,770

2 Claims.

This invention relates to bushing insulators and has for one of its objects the provision of a sealing means for insulators of the compression type which shall be easy to assemble with the insulator without the use of soldered joints.

A further object of the invention is to provide an improved packed joint between the insulator and the supporting structure which will prevent leakage of oil or other insulating liquid past the insulator flange.

A further object of the invention is to provide improved means for centering the internal baffle of the insulator.

A further object of the invention is to pro- ,vide a device of the class named which shall be of improved construction and operation.

Other objects and advantages will appear from the following description.

The invention is exemplified by the combina tion and arrangement of parts shown in the accompanying drawing and described in the following speciiication and it is more particularly pointed out in the appended claims.

In the drawing, the figure is a part elevation and part section of a bushing insulator showing one embodiment of the invention.

In the embodiment shown, the insulator comprises an outer shell or dielectric tube I and an inner dielectric baille II. These dielectric members may be made of porcelain or other suitable dielectric material. The insulator extends through an opening in a supporting member I2 which may be the cover of a housing for electrical apparatus or any other suitable member through which it is desirable to extend an electrical conductor. A iiange I3 is secured to the shell member I0 by cement I4, the flange having an inner beveled surface for engaging a packing ring I5. The ring I5 is preferably made of some suitable packing material that will withstand the* action of oil or other insulating liquids with which the housing I2 may be filled. A synthetic rubber is suitable for this purpose. A metal ring IB is also provided with a beveled face for engaging the lower portion of the packing ring I5, the two beveled faces cooperating to compress the packing tightly against the outer surface of the shell I0 to form a liquid-tight joint between the flange and bushing. The metal ring I6 rests upon a gasket II which is supported on the housing cover I2. The flange I3 is secured to the cover I2 by bolts I8 which compress the gasket I'I and the packing ring I5.

The lower end of the bushing I0 is closed by a terminal plate I9 which bears upon a gasket 20 engaging the lower end of the member I0. The plate I9 is threaded on the lower end of the conductor rod 2I which extends upwardly through the bushing, the upper end being secured by a nut 22 which rests upon a washer 23 supported by a helical spring 24. The spring 24 is surrounded by a pocket member 25 having a ring 26 threaded into its lower end for supporting the spring 24. The upper end of the pocket member E5 is provided with a radial flange 21 which rests upon a gasket 28 supported by the upper end of the member I0. An integral cover 29 closes the upper end of the pocket member 25 and carries a threaded stud 30 for receiving the connected conductor. The cover 29 may be perforated for filling the bushing, a pipe plug 3| being used to close the perforation when the bushing is filled. The major portion of the space within the shell member Il) below the pocket member 25 is occupied by the supplemental dielectric tube I I which rests upon a centering ring 32 supported on the closure plate I9. The ring 32 may be made of resilient material, such as synthetic rubber, and its outer face is beveled so as to center the lower end of the ring relative to the conductor 2|. The conductor 2| is provided with a peripheral groove 33 at the upper end of the supplemental tube II and a resilient ring of synthetic rubber 34 surrounds the conductor at this point and is held in place by the groove 33. The upper end of the tube II is provided with an inner beveled surface which engages the ring 34 to center the upper end of the tube. Grooves 35 and 36 may be provided to permit circulation of the illling liquid past the ends of the tube II. A drain plug 3l may be provided in the terminal plate I9 for draining the bushing when necessary.

In assembling the bushing the nut 22 is threaded on the upper end of the conductor 2l and the washer 23 and spring 24 are moved over the conductor into the position shown in the drawing. The pocket member 25, with the ring 26 removed, is then moved downwardly over the spring and the ring 26 moved upwardly over the conductor and threaded into the lower end of the pocket member to hold the spring in place. The packing ring 34 is then moved into place from the lower end of the conductor and has sufficient resiliency to be drawn tightly into the groove 33. The conductor with the pocket member 25 in place is then moved into the shell member I0 through the upper end and the supplemental tube II is moved over the conductor through the lower end of the shell member III.

The centering ring 32 is then moved into position in Contact with the lower end of the tube Il and the terminal plate I9 screwed onto the lower end of the conductor. The terminal member 3l] has a central threaded opening 38 through which a tool is threaded into contact with the upper end of the conductor 2| and sufficient pressure is exerted by the tool on the conductor to compress the spring 24. The cover plate I9 is screwed up against the gasket 2D and after the tool has been removed the spring 25 expands and draws the terminal plate I9 and the flange 21 tightly against their respective gaskets so as to provide a completely sealed bushing. A pipe plug is then tightly threaded into the tapered upper end ofthe opening in the terminal l3l) to seal the opening.

It will be noted that the space for filling liquid Within the bushing is exceedingly small so that there will be but very little expansion or contraction of the filling liquid. The bushing may be filled through the upper end and sufficient liquid is placed within the bushing to bring the surface level slightly above the lower end of the pocket member 25. This will leave suflicient air space in the upper end of the bushing to form a cushion to accommodate the expansion and contraction of the filling liquid. This, as explained, will be relatively small since there is only a small quantity of liquid within the bushlng.

This constitutes a division of Serial No. 311,783, filed December 30, 1939, which has matured into Patent No. 2,280,032, dated April 14, 1942.

That which is regarded new, novel and useful and which is sought to be protected by Letters Patent of the United States is as follows:

I claim:

1. In combination a support having an opening therethrough, a tubular dielectric member extending through said opening, a ange secured to said dielectric member and having a beveled face adjacent the outer periphery of said tubular dielectric member, a packing ring surrounding said tubular dielectric member and engaging said beveled face, a pressure ring having a beveled face engaging said packing ring, said pressure ring being movable relative to said iiange to compress said packing ring against the outer face of said tubular dielectric member, a gasket interposed between said pressure ring and support and threaded means for clamping said flange to said support and for compressing said packing ring and gasket.

2. T'he combination with a supporting member having an opening therethrough, of a dielectric tube extending through said opening and means for forming a sealed joint between `said tube and member, said means comprising a iiange fixed to said tube and projecting radially therefrom in overlapping relation with said support, a gasket on said support surrounding said tube, a ring resting on said gasket, packing surroundl ing said tube between said flange and ring, said ange and ring each having a beveled surface engaging said packing and bolts securing said Iiange to said support and clamping said packing between said beveled surfaces and against said tube and also clamping said ring on said gasket.

THOMAS F. BRANDT.

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