Abstract: A process of making a continuous thermoplastic helical seam profile pipe. The thermoplastic material is extruded through a die to form a continuous square tube. The continuous tube is cooled and a filler material is applied. The continuous tube bearing the applied filler material is helically wound to form turns of wound continuous tube. Each turn of the continuous tube is pressed into the preceding turn on the mandrel for adhering the turns together to form the pipe. Apparatus for producing a helical seam profile pipe includes a frame, and a mandrel mounted on the frame for rotation on the frame about a longitudinal axis of the mandrel to helically wind the thermoplastic tube around the mandrel. A source of filler material, and a filler material applicator located adjacent to the mandrel continuously apply a bead of the filler material to the thermoplastic tube prior to being wound on the mandrel.

Abstract: A process of making a continuous thermoplastic helical seam profile pipe. The thermoplastic material is extruded through a die to form a continuous square tube. The continuous tube is cooled and a filler material is applied. The continuous tube bearing the applied filler material is helically wound to form turns of wound continuous tube. Each turn of the continuous tube is pressed into the preceding turn on the mandrel for adhering the turns together to form the pipe. Apparatus for producing a helical seam profile pipe includes a frame, and a mandrel mounted on the frame for rotation on the frame about a longitudinal axis of the mandrel to helically wind the thermoplastic tube around the mandrel. A source of filler material, and a filler material applicator located adjacent to the mandrel continuously apply a bead of the filler material to the thermoplastic tube prior to being wound on the mandrel.

Abstract: A method for forming a branch in a pipe made of polymeric material which permits a strong joint to be formed at the branch to another pipe. A system for carrying out the method includes heaters which soften the polymeric material in a highly localized manner. A forming member is pulled through the softened material to deform the pipe wall and form a branch. A method for making reinforced pipe joints in which pipe sections are force fit into each other is also disclosed.

Abstract: A method for forming a branch in a pipe made of polymeric material which permits a strong joint to be formed at the branch to another pipe. A system for carrying out the method includes heaters which soften the polymeric material in a highly localized manner. A forming member is pulled through the softened material to deform the pipe wall and form a branch. A method for making reinforced pipe joints in which pipe sections are force fit into each other is also disclosed.

Abstract: A pipe joint for first and second profile wall pipes of the type having generally concentric, spaced apart inner and outer walls, and a helical rib connecting the inner wall to the outer wall. The convolutions of the helical rib extend in multiple turns around the exterior of the inner wall and along the interior of the outer wall for substantially the entire length of the pipe. The pipe joint includes a first exposed portion of the rib of the first pipe, and a second exposed portion of the rib of the second pipe. The exposed helical rib of the first pipe is threadably interengaged with the exposed helical rib of the second pipe.