Isolation gasket for critical service flow line applications

Abstract

An isolation gasket is provided for interposition between joined pieces of a flow line. The gasket has a gasket body which electrically isolates the pieces from one another. In one embodiment the gasket has a pair of composite, insulative linings laminated on opposite sides of a metal core. An endless channel on each side of the gasket body surrounds a central flow opening and is formed of a depth sufficient to extend through the insulative lining and into the metal core. The outer sidewall of each endless channel is at an acute angle to its bottom wall, and the inner sidewall is at an angle of at least ninety degrees with respect to the bottom wall. The channels may be opposed to or offset from one another. Different channel cross-sections are described. An alternative gasket body may eliminate the metal core and be either a laminated composite body or of integral construction. Here, the endless channels are offset, and depths of the endless channels together exceed the gasket thickness so that the channels overlap to prevent radial fluid migration. In each case, seal elements are disposed in each channel and are configured so that the acutely angled channel outer sidewalls reduce the danger of gasket rollout.