Space and temperature accommodating self-cleaning weather casing and high voltage insulating structure employing the same

Claim 2

Bushing apparatus for mounting outdoors where the bushing will be required to operate in an ambient temperature which varies over a wide range comprising, in combination, a rigid bushing body having a conductor stud extending therethrough with at least one end having a portion extending beyond the bushing body, a groundable sleeve of conductive material mounted at a selected axial position on the bushing body, a weather casing having spaced sheds along the length thereof and having at least the body portion thereof composed of resilient and elastic material, the inside surface of the weather casing enclosing a substantial space between it and the adjacent body portion of the bushing, means clamping one end of the weather casing to the conductor stud and other means clamping the other end of the weather casing to the ground sleeve, and a volume of liquid insulating material completely filling said space without leaving any gas therein, said volume being sufficiently great that when inserted in the bushing before sealing the space by one of the clamping means the elastic weather casing undergoes substantial stretching, the weather casing after the liquid insulating material is sealed in the bushing by one of said clamp means undergoing further stretching and expansion as needed to contain an expanded volume of liquid due to a temperature rise therein resulting from at least one of the factors including ambient temperature, heat generated by current flowing in the Conductor stud, and heat generated in the dielectric of the bushing, the weather casing contracting when the volume of the liquid insulating material decreases due to a reduction in the temperature thereof and enclosing the volume of liquid without permitting any airspace to form inside the bushing.

Claim 3

A bushing according to claim 1 in which the liquid insulating material is oil.

Claim 4

A bushing for outdoor use having a rigid bushing body composed of insulating material and of substantially uniform outside diameter along the length thereof, a conductor stud extending through the bushing, a groundable sleeve of conductive material enclosing a selected axial portion of the bushing body and secured to the same, the conductor stud having a threaded end extending beyond an adjacent end of the bushing body, a weather casing composed of resilient and elastic electrical insulating material enclosing substantially that portion of the bushing body which extends from the groundable sleeve to the extended end of the conductor stud, a pair of means securing the weather casing to the groundable sleeve and to the conductor stud, the casing having spaced sheds along the length thereof, and an insulating filler material of substantial volume between the inside wall of the weather casing and the outside wall of the bushing body, the casing being stretched when the filler material is inserted and thereafter sealed within by at least one of the securing means, the stretched weather casing keeping the filling compound under pressure at all times thereby preventing voids which would tend to produce deterioration of the dielectric and radio interference.

Claim 5

A bushing for outdoor use having a rigid bushing body composed of insulating material and of substantially uniform outside diameter along the length thereof, a conductor stud extending through the bushing, a groundable sleeve of conductive material enclosing a selected axial portion of the bushing body and secured to the same, the conductor stud having a threaded end extending beyond an adjacent end of the bushing body, a weather casing composed of resilient and elastic electrical insulating material enclosing substantially that portion of the bushing body which extends from the groundable sleeve to the extended end of the conductor stud, a pair of means securing the weather casing to the groundable sleeve and to the conductor stud, the casing having spaced sheds along the length thereof, and an insulating filler material of substantial volume between the inside wall of the weather casing and the outside wall of the bushing body, the casing being stretched when the filler material is inserted and thereafter sealed within by at least one of the securing means, the stretched weather casing keeping the filling compound under pressure at all times thereby preventing voids which would tend to produce deterioration of the dielectric and radio interference.

Claim 6

A bushing according to claim 3 in which the sheds extending from the weather casing increase in outside diameter in graduated steps as their distance from the groundable sleeve becomes less to provide lower sheds which extend out farther from the body of the weather casing than the upper sheds to thereby improve washoff from the lower sheds and tend to maintain the creep resistance across the weather casing between surfaces of opposite polarity at its maximum value.

Claim 7

Insulating apparatus for mounting outdoors where the apparatus will be located in an ambient temperature which varies over a wide range comprising, in combination, an elongated rigid member composed of electrically insulating material having connecting means secured to one end thereof and adapted to be mounted at the other end thereof to a supporting structure, a weather casing composed or resilient and elastic electrically insulating material encasing the rigid member, means at each end of the casing clamping the casing to the rigid member, and a substantial volume of oil enclosed in a spaced between the inside wall of the casing and the wall of the rigid member, the elastic casing being stretched to enclose the volume of oil when first inserted in the apparatus and thereafter clamped to form a sealed chamber for the oil, the elastic casing stretching to accommodate an increase in the volume of oil due to an increase in the temperature thereof, the elastic casing shrinking to accommodate a decrease in the volume of oil due to a decrease in the temperature thereof to thereby maintain a space completely filled with oil and having no air pocket therein.

Claim 8

Insulating apparatus for mounting outdoors where the apparatus will be located in an ambient temperature which varies over a wide range comprising, in combination, an elongated rigid member composed of electrically insulating material having connecting means secured to one end thereof and adapted to be mounted at the other end thereof to a supporting structure, a weather casing composed or resilient and elastic electrically insulating material encasing the rigid member, means at each end of the casing clamping the casing to the rigid member, and a substantial volume of oil enclosed in a spaced between the inside wall of the casing and the wall of the rigid member, the elastic casing being stretched to enclose the volume of oil when first inserted in the apparatus and thereafter clamped to form a sealed chamber for the oil, the elastic casing stretching to accommodate an increase in the volume of oil due to an increase in the temperature thereof, the elastic casing shrinking to accommodate a decrease in the volume of oil due to a decrease in the temperature thereof to thereby maintain a space completely filled with oil and having no air pocket therein.

Claim 9

A substantially self-cleaning, substantially weatherproof high voltage bushing comprising an elongated body portion having an axial bore therethrough, the elongated body portion being composed of rigid insulating material, a conductor stud extending through said bore, said body portion having an annular groove therearound at a predetermined axial position, a ground flange composed of conductive material having a cylindrical portion extending at least partially into the groove and having an extended flange portion, said ground flange being adapted to be mounted in a position whereby a portion of the bushing on one side of the ground flange is exposed to the weather, the portion of the bushing body within Said last-named portion of the bushing tapering from a relatively large diameter near the ground flange to a relatively small diameter at the end of the conductor stud extending from said last-named portion a weather casing of resilient insulating material covering said last-named portion of the bushing body, the casing of resilient insulating material having a portion of reduced diameter at the end thereof adjacent the conductor stud and closely fitting the conductor stud, the potion of the weather casing at the other end thereof adjacent the ground flange extending down over the outside of the adjacent cylindrical portion of the ground flange, clamping means clamping said last-named portion of the weather casing around the ground flange in moistureproof sealing engagement therewith, other clamping means clamping the portion of reduced diameter of the weather casing to the conductor stud in moistureproof sealing engagement therewith, the weather casing having axially spaced sheds normally extending therefrom substantially perpendicular to the longitudinal axis of the bushing and the casing, all said sheds having substantially flat upper and lower surfaces, the sheds extending equal distances from the body of the casing, said tapering portion of the bushing body providing that sheds near the ground flange extend radially beyond sheds near said end of the conductor stud whereby washoff of the sheds near the ground flange is facilitated and more effective self-cleaning is provided, the body portion of the weather casing being so resilient that the sheds are moved from their normal portions by the force of wind thereon, dislodging snow and breaking any ice formed thereon.

Claim 10

A substantially self-cleaning, substantially weatherproof high voltage bushing comprising an elongated body portion having an axial bore therethrough, the elongated body portion being composed of rigid insulating material, a conductor stud extending through said bore, said body portion having an annular groove therearound at a predetermined axial position, a ground flange composed of conductive material having a cylindrical portion extending at least partially into the groove and having an extended flange portion, said ground flange being adapted to be mounted in a position whereby a portion of the bushing on one side of the ground flange is exposed to the weather, the portion of the bushing body within Said last-named portion of the bushing tapering from a relatively large diameter near the ground flange to a relatively small diameter at the end of the conductor stud extending from said last-named portion a weather casing of resilient insulating material covering said last-named portion of the bushing body, the casing of resilient insulating material having a portion of reduced diameter at the end thereof adjacent the conductor stud and closely fitting the conductor stud, the potion of the weather casing at the other end thereof adjacent the ground flange extending down over the outside of the adjacent cylindrical portion of the ground flange, clamping means clamping said last-named portion of the weather casing around the ground flange in moistureproof sealing engagement therewith, other clamping means clamping the portion of reduced diameter of the weather casing to the conductor stud in moistureproof sealing engagement therewith, the weather casing having axially spaced sheds normally extending therefrom substantially perpendicular to the longitudinal axis of the bushing and the casing, all said sheds having substantially flat upper and lower surfaces, the sheds extending equal distances from the body of the casing, said tapering portion of the bushing body providing that sheds near the ground flange extend radially beyond sheds near said end of the conductor stud whereby washoff of the sheds near the ground flange is facilitated and more effective self-cleaning is provided, the body portion of the weather casing being so resilient that the sheds are moved from their normal portions by the force of wind thereon, dislodging snow and breaking any ice formed thereon.

Claim 11

A weather casing for use on a bushing having an elongated body portion composed of rigid insulating material, a conductor stud extending therethrough, and a ground flange disposed in predetermined axial position along the length of the bushing, the body portion of the bushing on one side of the ground flange tapering from a relatively large outer diameter adjacent the ground flange to a relatively small outer diameter adjacent the end of the conductor stud extending from the bushing on that side of the ground flange, the weather casing being composed of resilient electrical insulating material, the weather casing being of tapering diameter and preformed to be slipped over the end of the conductor stud and onto the bushing body and having a portion of relatively large diameter to extend over at least a portion of the ground flange and adapted to be clamped to the ground flange, the weather casing having a portion of small diameter relative to the first-named portion and shaped to closely fit the end of the conductor stud and adapted to be clamped thereto, the weather casing having a plurality of axially spaced sheds normally extending therefrom substantially perpendicular to the axis of the casing while the casing is mounted on the bushing, all said sheds having substantially flat upper and lower surfaces while the casing is mounted on the bushing, the sheds extending equal distances from the body of the casing, the slope of the outside surface of the weather casing resulting from the tapering diameter thereof causing the sheds thereof near the ground flange to extend radially beyond the sheds thereof near said end of the conductor studs whereby more effective self-cleaning of the casing surface is provided by increasing the washoff of the sheds near the ground flange, the body portion of the weather casing being so resilient that the sheds are moved from their normal positions by the force of wind thereon, dislodging snow and breaking any ice formed thereon.

Claim 12

A weather casing for use on a bushing having an elongated body portion composed of rigid insulating material, a conductor stud extending therethrough, and a ground flange disposed in predetermined axial position along the length of the bushing, the body portion of the bushing on one side of the ground flange tapering from a relatively large outer diameter adjacent the ground flange to a relatively small outer diameter adjacent the end of the conductor stud extending from the bushing on that side of the ground flange, the weather casing being composed of resilient electrical insulating material, the weather casing being of tapering diameter and preformed to be slipped over the end of the conductor stud and onto the bushing body and having a portion of relatively large diameter to extend over at least a portion of the ground flange and adapted to be clamped to the ground flange, the weather casing having a portion of small diameter relative to the first-named portion and shaped to closely fit the end of the conductor stud and adapted to be clamped thereto, the weather casing having a plurality of axially spaced sheds normally extending therefrom substantially perpendicular to the axis of the casing while the casing is mounted on the bushing, all said sheds having substantially flat upper and lower surfaces while the casing is mounted on the bushing, the sheds extending equal distances from the body of the casing, the slope of the outside surface of the weather casing resulting from the tapering diameter thereof causing the sheds thereof near the ground flange to extend radially beyond the sheds thereof near said end of the conductor studs whereby more effective self-cleaning of the casing surface is provided by increasing the washoff of the sheds near the ground flange, the body portion of the weather casing being so resilient that the sheds are moved from their normal positions by the force of wind thereon, dislodging snow and breaking any ice formed thereon.

Claim 13

Bushing apparatus for outdoor mounting comprising, in combination, a rigid bushing body having a conductor stud extending therethrough with at least one end having a portion extending beyond the bushing body, a groundable sleeve of conductive material mounted at a selected axial position on the bushing body, a weather casing having at least the body portion thereof composed of resilient, flexible, and elastic material, having axially spaced sheds extending from the body portion along the length thereof and enclosing that portion of the bushing body which extends from the groundable sleeve to the extending portion of the conductor stud, means securing one end of the casing to the groundable sleeve and other means securing the other end of the weather casing at the conductor stud, both securing means providing weatherproof sealing, the material of the body portion of the weather casing being so elastic and flexible that the sheds are moved out of their normal positions by winds thereby breaking ice formed thereon and throwing off snow accumulated thereon, the bushing having an oil-filled space between the inside wall of the body portion of the weather casing and the wall of the rigid bushing body, said oil-filled space extending substantially the length of the weather casing, the fluid oil assisting in making the sheds more responsive to the force of the wind thereon.

Claim 14

Bushing apparatus for outdoor mounting comprising, in combination, a rigid bushing body having a conductor stud extending therethrough with at least one end having a portion extending beyond the bushing body, a groundable sleeve of conductive material mounted at a selected axial position on the bushing body, a weather casing having at least the body portion thereof composed of resilient, flexible, and elastic material, having axially spaced sheds extending from the body portion along the length thereof and enclosing that portion of the bushing body which extends from the groundable sleeve to the extending portion of the conductor stud, means securing one end of the casing to the groundable sleeve and other means securing the other end of the weather casing at the conductor stud, both securing means providing weatherproof sealing, the material of the body portion of the weather casing being so elastic and flexible that the sheds are moved out of their normal positions by winds thereby breaking ice formed thereon and throwing off snow accumulated thereon, the bushing having an oil-filled space between the inside wall of the body portion of the weather casing and the wall of the rigid bushing body, said oil-filled space extending substantially the length of the weather casing, the fluid oil assisting in making the sheds more responsive to the force of the wind thereon.

Claim 15

Bushing apparatus according to claim 8 in which both securing means are clamping means securing the weather casing to the groundable sleeve and to the conductor stud.

Claim 16

Bushing apparatus according to claim 8 in which the rigid bushing body has a diameter which tapers from a relatively large value at one end thereof to a relatively small value at the other end thereof remote from the groundable sleeve, and in which the casing has sheds which extend a substantially uniform distance from the body of the casing, the tapered shape of the rigid bushing body insuring that the lower sheds extend in graduated steps beyond a shed immediately thereabove, thereby ensuring that the lower sheds have more rain reach the surfaces thereof to enhance washoff of contaminant.

Claim 17

A bushing according to claim 8 in which the rigid bushing body has a diameter which is substantially uniform over the entire length thereof, and in which the sheds on the casing extend graduated increasing distances from the body of the casing as the sheds approach the portion of the rigid bushing body near the groundable sleeve, to thereby enhance washoff of deposited contaminant by rain from all the sheds.