Patent Application
20090095506
The present invention relates to a collar assembly for an integrated insulator sealing and shielding assembly. More particularly, the invention represents an integrated insulator sealing and shielding assembly with a rubber housing having a plurality of radial weathersheds and a tapered end adjacent to the endmost radial weathershed. A metal fitting is disposed adjacent to the endmost radial weathershed and receives the tapered end of the rubber housing. A collar assembly surrounds the connection between the metal fitting and the rubber housing. The collar assembly further includes two apertures between an outer surface thereof and the rubber housing for receiving a sealant. There are preferably multiple sealing surfaces disposed between the collar assembly and a bottom end of the rubber housing for securing the connection therebetween.
Electrical polymer insulators are used in power transmission and distribution systems to provide mechanical support for conductors and provide electrical insulation between the high voltage conductors and grounded tower structures. A corona protection device is located at the line end and/or the ground end of the insulator and eliminates the corona discharge from the insulator. Elimination of the corona discharge protects the surface of the insulator from polymeric material deterioration caused by electrical stress. Additionally, eliminating the corona discharge reduces television and/or radio noise created by the corona discharge.
One of the problems with conventional corona protection devices is the number of parts required to assemble the corona protection device, thereby increasing the manufacturing costs. Additionally, an installer must transport more parts to a job site, which decreases the speed and efficiency with which the corona protection devices may be installed. Since existing corona protection devices require various parts in order to completely assemble the device, if one part is lost or missing, the device cannot be properly assembled. Thus, an installer must make a return trip to finish installation of the corona discharge device. A need then exists for a collar assembly having few parts, thereby reducing manufacturing costs and providing quick installation.
Other problems with existing corona protection devices involve poor seals being formed between the corona protection device and the insulator, as well as the corona protection device being poorly secured to the insulator. Inadequate seals and connections to the insulators result in a highly ineffective corona protection device, often resulting in failure of the corona protection device. Thus, a need exists for a collar assembly having a good seal and connection to the insulator.
Examples of conventional corona protection devices include U.S. Pat. No. 2,867,682 to Smith et al.; U.S. Pat. No. 4,198,538 to Lusk; U.S. Pat. No. 5,488,199 to Selsing et al.; U.S. Pat. No. 6,265,669 to Richards; U.S. Pat. No. 6,388,197 to Zhao et al.; the subject matter of each of which is hereby incorporated by reference.
Conventional external metal collars clamp down on a cylindrical polymer surface to create a void in the sealing system. Accordingly, a need exists for an improved insulator collar assembly having a metal fitting and a rubber housing forming a compression seal to an external stationary cylindrical metal element.
Accordingly, an object of the invention is to provide an improved insulator sealing and shielding assembly.
Another object of the invention is to provide an insulator shielding having a collar assembly disposed between a rubber housing and a metal fitting where the collar includes at least one opening for receiving a sealant.
A further object of the invention is to provide an insulator shielding with a rubber housing tapered into a metal fitting to increase the compression connection therebetween.
Still another object of the invention is to provide an insulator shielding with a plurality of equidistant radial weathersheds disposed along an exterior of the housing and the endmost weathershed adjacent to the collar assembly connected to the hardware.
The foregoing objects are basically attained by providing an insulator shielding having a rubber housing with a plurality of weathersheds and a tapered end adjacent the metal fitting. Four sealing surfaces between the counterbore of the collar assembly and the rubber housing secure the connection therebetween creating an integral metal fitting and rubber housing. The collar assembly comprises at least one aperture for receiving a sealant that creates a mold to help secure the connection.
By forming the insulator sealing and shielding assembly in this manner, a sealant can be dispensed into one of the apertures until the collar assembly is full of sealant to create a first seal. Three additional sealing surfaces protect the initial seal against moisture ingress and seal the flow channel to effectively bond the rubber housing and metal fitting.
As used in this application, the terms “top”, “bottom”, and “side” are intended to facilitate the description of the invention, and are not intended to limit the present invention to any particular orientation.
Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with annexed drawings, discloses a preferred embodiment of the present invention.
Referring to drawings that form a part of this disclosure:
Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures.
Referring to
Ultimately, the rubber housing 14 is adapted to be inserted into and connected to each metal fitting 18 under pressure. Since each metal fitting 18 and collar assembly 12 is identical, only one will be described in detail.
The weathersheds 16 are spaced apart equal distances from one another along the body of the insulator assembly 10. All weathersheds 16 have the same diameter. At the outer edge of the axially endmost weathershed 16′, the end 30 of the rubber housing 14 tapers towards the side of the assembly 10 with the metal fitting 18. The endmost weathershed 16′ is adjacent to and abuts the collar assembly 12, further illustrated in
The collar assembly 12 surrounds the interface between the metal fitting 18 and the rubber housing 14, as shown in
Turning to
The collar assembly 12 also includes a counterbore 15 that receives the tapered end 30. The counterbore 15 is a passage extending between the first and second apertures 20, 22 and adjacent to the tapered end 30 of the rubber housing 14. This helps create the connection between the collar assembly 12 and the rubber housing 14.
Each aperture 20, 22 makes up the counterbore 15 passing lengthwise along the diameter of the collar assembly 12. The counterbore 15 is the main opening between the rubber housing 14 and the metal fitting 18.
As seen in
As seen in
The third sealing surface 44 is located towards the intersection of the second aperture 22 and the rubber housing 14. This is known as the room temperature vulcanizing (RTV) fill because material is injected into the first aperture 20 between the rubber housing 14 and the collar assembly 12. Each aperture 20, 22 is defined by a perpendicular extension or projection 20′, 22′, respectively, that extends towards the plurality of weathersheds 16. These extensions 20′, 22′ of the apertures 20, 22, respectively connect the apertures 20, 22 to the tapered end 30 of the rubber housing 14. This connection assists in creating a mold because the openings 20, 22 and 20′, 22′ receive the sealant material between the rubber housing 14 and the collar assembly 12 and shape the cast of the sealant material or RTV. RTV is preferred material because it bonds to silicone rubber and metals.
The material injected is a sealant which may be either a room temperature or high temperature vulcanizing material. Sealant is pumped into the fitting at the first aperture 20 until enough sealant is disposed or stored in both the first aperture 20 and the second aperture 22 and sealant overflows. When the maximum limit of sealant has been reached, excess sealant begins to emerge and overflows from the opposite aperture 22 so the installer knows a sealed fit has been formed within the interior of the metal fitting 18, thus creating the third sealing surface 44.
The fourth sealing surface 46 is located towards the top of the collar assembly 12 at the junction of the rubber housing 14 and the outer portion 64 of the counterbore 15. This sealing surface 46 is the lip seal defined by the intersection of a raised rib 50 on the rubber housing 14 and the outer portion of the counterbore 15 to provide an initial seal against moisture ingress. It also seals the flow channel to keep the RTV adjacent to the rubber housing 14 until it cures. The raised rib 50 is the lowermost extension of the rubber housing 14 on the side of the endmost weathershed 16′ adjacent the collar assembly 12.
While a particular embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.
