US 5,408,047 A · Transition joint for oil-filled cables

Abstract

A transition joint for sealing an electrical coaxial cable having an oil-impregnated or fluid filled layer. The transition joint has two primary elements, an electrically insulative elastomeric tube and a heat recoverable sleeve. In connecting a paper-insulated, lead jacketed cable to an extruded dielectric cable, the elastomeric tube is placed in tight conformity around the paper layer, slightly overlapping the lead jacket and the central conductor, and further partially overlapping a connector joining the conductors of the cables. The heat recoverable sleeve is then contracted over the elastomeric tube, overlapping the lead jacket and the central conductor, and partially overlapping the connector. The heat recoverable sleeve mechanically restricts the elastomeric tube, preventing the elastomeric tube from swelling which, in turn, precludes absorption of the oil, which would otherwise cause the elastomer to degrade. A flexible tape may be substituted for the heat recoverable sleeve to provide the mechanical confining pressure. If the cable has an additional semiconducting layer, a high-dielectric tape may be used for dielectric stress control.

Claims14

Dependent claims

A transition joint at the terminal end of a coaxial cable having a partially exposed central conductor, a partially exposed, oil-impregnated, electrically insulative paper layer surrounding the conductor, a partially exposed semiconducting layer surrounding the paper layer, and a lead jacket surrounding the semiconducting layer, the transition joint comprising:

a high-dielectric constant tape wrapped around the terminal end of the lead jacket and the exposed portion of the semiconducting layer;
an electrically insulative, oil-permeable, elastomeric tube having a length which is greater than the combined lengths of the exposed portions of the semiconducting and paper layers, said elastomeric tube contacting and surrounding said dielectric tape and the exposed portion of the paper layer, and said elastomeric tube being constructed of a material which degrades upon substantial absorption of oil from said oil-impregnated paper layer;
and
a layer of electrically insulative tape contacting, surrounding and confining said elastomeric tube, and restricting absorption of said oil by said elastomeric tube.

1 more element

A method of converting the terminal end of a coaxial cable having a central conductor, a layer of oil-impregnated paper surrounding the conductor, and an electrically conductive jacket surrounding the paper layer, comprising the steps of:

removing a portion of the jacket, thereby partially exposing the paper layer;
cutting away a portion of the paper layer, thereby partially exposing the central conductor;
placing an electrically insulative, oil-permeable, elastomeric tube in tight conformity around the entire exposed portion of the paper layer and in direct contact with said paper layer, said elastomeric tube being constructed of a material which degrades upon substantial absorption of oil from said oil-impregated paper layer;
and
applying an electrically insulative tape layer around the elastomeric tube whereby the insulative tape layer imparts sufficient confinement pressure about the elastomeric tube to prevent any significant absorption of oil by the elastomeric tube, the insulative tape layer being sufficiently long to overlap the conductive jacket at one end and overlap the central conductor at the other end.

2 more elements

Dependencies are inferred from the claim text.

Transition joint for oil-filled cables

Life of this patent

Transition joint for oil-filled cables

Life of this patent

Abstract

Claims14