Apparatus and Method for Joining Molecularly Oriented Pipe

A pipe joint, comprising:

• a first longitudinal section of molecularly oriented pipe and a second longitudinal section of molecularly oriented pipe, each of the longitudinal sections of molecularly oriented pipe having at least one plain, spigot end having a given external diameter and a mating socket end having a given internal diameter;
• wherein the first section of pipe has a straight, pre-formed socket with an internal diameter and with an end opening having enough clearance whereby a mating spigot section having a given external diameter can be received within the socket end opening, the spigot section being inserted to a preselected depth within the socket end opening;
• wherein the pipe joint is formed by heating the socket so that the internal diameter of the socket comes into contact with the external diameter of the spigot, the molecularly oriented pipe being in a rubbery state exhibiting a low elastic modulus which allows the socket to conform tightly to the spigot external, diameter without deforming the spigot, followed by cooling the socket to about 55 degrees C. whereby the socket undergoes thermal contraction to produce an interference fit on the order of 0.5% with the spigot.

pipe joint of claim 17, wherein the mechanical gripping element is selected rom the group consisting of a metallic and rubber sleeve composite and a wire mesh sleeve.