Equipment for welding pipe elements of a melt-weldable plastic material comprises a heatable metal plate and first and second heat-conductive elements attached respectively to first and second opposed faces of the plate. The first element has a concave melting surface of elliptical cross-section which is complementary in shape to that of the circumference of a manifold pipe to be heat-welded. The melting surface is raised and has a reduced wall thickness along its minor axis and is depressed and has an increased thickness along its major axis. A pipe fitting for use with the welding tool has a welding end which is substantially identical in configuration to that of the melting surface of the first element. The second element is complementary in shape to the end of the pipe fitting for melting the welding end of the pipe fitting. In a process for welding the pipe fitting to the pipe manifold using the welding tool, the heated first and second elements are brought into contact with the circumference of the manifold pipe and the welding end of the pipe fitting, respectively, until incipient melting occurs. The first element is aligned with a hole in the manifold using a non-conductive central element inserted in a central axial cavity in the first element. The melted areas are then brought into contact with each other under pressure and allowed to solidify.

The present invention is directed to a method and apparatus for fusing a sidewall pipe onto a host pipe using pneumatic equipment. The functions of the fusing apparatus are controlled by a programmable computer. Further, as each fuse is performed, a GPS system provides and stores the geographical location of the fuse.

A method for welding a first member and a second plastic member, the first member having a first surface and the second member having a second surface which are to be welded to each other, the surfaces having different shape configurations nonconforming to each other includes positioning the first member transversely with respect to the second member with the nonconforming surfaces facing each other, heating the first surface at a welding temperature and transforming the shape of the first surface such as to at least partially conform it to the shape of the second surface, heating the second surface at a welding temperature at the surface area corresponding in size and contour configuration to the first surface and at the location where the first surface is to be welded to the second surface, and welding the first and second heated surface together.

The present invention is directed to an apparatus for fusing a sidewall pipe onto a host pipe at an angle of less than 90.degree.. The apparatus prevents the angled sidewall pipe from migrating during the fusing operation. Also provided is a radius cutter for cutting the radius of the angled sidewall pipe to match the concave upper surface of the host pipe.

A fitting for coupling a service line to a polyethylene fluid distribution pipe such as a water main or a gas main includes a stub length of polyethylene pipe that serves as a base for attaching a corporation stop valve. The cross section of the open base end is machined to match the curvature of the outside surface of the main pipe and then fused into the sidewall of the main. The corporation stop valve can then be used for hot tapping polyethylene mains.