Abstract: A flanged joint assembly for a lined pipeline having a plastic liner and in which the joint is sealed by compression of mating plastic flanges between mating steel flanges and in which plastic flange portions are differentially compressible. Each plastic flange is constructed with a flat sealing face and a thickened outer edge portion in the form of an annular disk. In the assembled joint, compression of the plastic flange is essentially restricted to this thickened flange portion by controlling the size of one of several recesses machined into the face of the steel flange face to accommodate portions of the plastic flanges. A thickened inner annular portion of the circular plastic flange is formed to create a concave frusto-conical surface having its larger circular cross section spaced axially away from the flat sealing face.

Abstract: There is disclosed a method of joining pipe sections of a given outside diameter, comprising the steps of providing a sleeve of a predetermined length and having an inside diameter slightly less than the outside diameter of the pipe section, forcing the end of one pipe section into one end of the sleeve to a distance approximately one half the length of the sleeve, to distend the one end of the sleeve radially to an extent slightly beyond the elastic limit of the material from which the sleeve is formed, forcing the end of the other pipe section into the second end of the sleeve to distend the second end of the sleeve radially to an extent slightly beyond its elastic limit while monitoring the force required to do so, and terminating forcing of the second pipe section into the second end of the sleeve when the required force as monitored starts to increase, indicating meeting of the ends of the pipe sections, whereby the contact pressure of the pipe ends is precisely regulated to ensure a correct contact pres