The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 11, 1997
Filed:
Jan. 18, 1996
Valerie Margaret Linton, Newcastle-upon-Tyne, GB;
Leslie Maine, Cramlington, GB;
British Gas plc, London, GB;
Abstract
The invention provides a joint 80 for two steel pipes 50, 52 each containing a liner 54, 56 of polyethylene. The invention also provides an electrofusion fitting for joining the liners 54, 56; a method of making the fitting and a method of making the joint 80. The joint 80 consists of an electrofusion fitting having two frusto-conical outer end surfaces which match similar surfaces on the insides of the end portions of the liners 54, 56. Fusion welded joints are formed at the interfaces between the frusto-conical surfaces. A body of insulating material 66 is received in a central recess in the fitting and protects the fitting from the high temperature of the seam 70 between the steel pipes 50, 52. The frusto-conical surfaces make an angle of 10.degree. or less with the longitudinal axis of the fitting. A support body 14 of metal or of synthetic plastics material contained by the electrofusion fitting ensures that the fitting is adequately supported during electrofusion.