Patent ID: 7918006

Claim:
A method for joining one end of each of first and second substantially equal sized inside and outside diameter pipe sections, comprising: forming a taper on the inside diameter of an end of a first pipe section end increasing in diameter in a direction towards said end to form female pipe end thereon, while maintaining the outside diameter of said first pipe section substantially constant along both said female pipe end and the remaining portion of said first pipe section; forming a complementary taper on the outside of an end of the second pipe section of increasing diameter in a direction away from said end to form a male pipe end thereon, said male pipe end larger in diameter along said taper than said taper on said female end while maintaining the inside diameter substantially constant, along said male pipe end and remaining portions of said second pipe section; heating the female pipe end to increase its inside diameter sufficiently to allow said female pipe end to be received over the male pipe end, and advancing said heated female pipe end over said male pipe end; and, thereafter cooling said female pipe end to contract said taper of said female pipe end so as to shrink grip said male pipe end tightly, whereby a pipe joint is formed having substantially the same inside and outside diameter as said remaining portions of said pipe sections.