US 4,398,754 AGranted

Electrically insulated pipe coupling and method for making the same

AssigneeKerotest Manufacturing Corp.

InventorsSteven J. Caroleo, Edward L. Schmitt

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Abstract

A connection between two pipes of a pipeline includes a pair of coupling members having externally threaded ends with sealing surfaces projecting from the ends. The threaded ends are advanced into opposite ends of an insulating sleeve fabricated of electrically nonconductive material. Internally threaded end portions of the sleeve are separated by an annular recessed portion. A resilient, nonconductive annular spacer is retained within the annular recessed portion. The spacer includes a pair of inclined inner sealing surfaces positioned in overlying sealing relation with the coupling member sealing surfaces and an outer sealing surface sealingly engaging the insulating sleeve to form a fluid and pressure tight seal around the annular space between the coupling members and the insulating sleeve in addition to electrically insulating the coupling members from each other. Upon the application of internal fluid pressure within the coupling members the sealing surfaces of the annular spacer are wedged into increasing sealing engagement with the coupling member sealing surfaces and the insulating sleeve so that the sealing forces generated between the respective components increase proportionally with an increase in the pipeline pressure.

Claims12

Dependent claims

An electrically insulated pipe coupling comprising,

a first coupling member and a second coupling member,
said first and second coupling members being positioned in axial alignment and including oppositely positioned end portions spaced from one another,
said oppositely positioned end portions each having an annular sealing surface,
an insulating sleeve having a bore therethrough for receiving and surrounding said coupling member end portions,
said first and second coupling member end portions being externally threaded and said insulating sleeve being internally threaded to receive and connect said first and second coupling members in spaced relation,
said insulating sleeve having opposite ends and an inner, annular recessed portion,
a resilient annular spacer retained in said insulating sleeve recessed portion between said coupling member end portions,
said annular spacer having an outer surface and an inner surface, said outer surface abutting said insulating sleeve,
said annular spacer including end portions overlapping said coupling member end portions and positioned oppositely of said insulating inner, annular recessed portion,
said annular spacer end portions having a plurality of inclined inner sealing surfaces on said inner surface and an outer sealing surface on said outer surface,
said coupling member end portions being axially advanced into the opposite ends of said insulating sleeve so that said annular sealing surfaces thereof are moved into sealing contact with said annular spacer inclined inner sealing surfaces,
said annular spacer outer sealing surface being expanded radially outwardly into sealing contact with said insulating sleeve to position said annular spacer end portions in abutting sealing relation with said insulating inner, annular recessed portion to form a fluid tight seal between said coupling member end portions and said insulating sleeve,
said annular spacer inner sealing surfaces and said outer sealing surfaces being wedged into sealing contact between said coupling member annular sealing surfaces and said insulating sleeve inner annular recessed portion,
a rigid reinforcing sleeve being in contact with and surrounding said insulating sleeve,
said rigid reinforcing sleeve being axially fixed on said insulating sleeve, and
means completely surrounding said rigid reinforcing sleeve for resisting corrosive damage to said reinforcing sleeve.

13 more elements

A method for making an electrically insulated pipe coupling comprising the steps of,

forming an annular sealing surface on the end of a first coupling member and the end of a second coupling member,
retaining a resilient annular spacer having a plurality of inclined, inner sealing surfaces and an outer sealing surface within an insulating sleeve intermediate the end portions of the sleeve,
inserting the ends of the first and second coupling members into opposite ends of the insulating sleeve,
advancing the coupling member annular sealing surfaces into compressing sealing relation with the annular spacer inclined inner sealing surfaces,
expanding the outer sealing surface of the annular spacer radially outwardly into sealing relation with the insulating sleeve to position the end portions of the annular spacer in abutting sealing relation with the insulating sleeve to form a fluid and pressure tight seal around the annular spacer between the first and second coupling members and the insulating sleeve and electrically insulate the first and second coupling members from each other,
externally reinforcing the insulating sleeve, and
completely surrounding the external reinforcing on the insulating sleeve with means to resist corrosive damage thereto.

4 more elements

Dependencies are inferred from the claim text.