Coupling for tubular plastic pipes with liner of socket and liner of

Abstract

Pipes to be joined and a pipe coupling have an outer sleeve made of a material optimized for linear and radial strength and positive connection and an inner portion or liner optimized for chemical inertness and the tightness of the connection. The pipes and coupling part are shaped to accommodate a material-correct joining procedure. Compound pipes (1) have a rigid, relatively thin pipe outer sleeve (3) for absorbing and transferring forces and a softer, relatively thin liner or inner pipe (4) to form a tight connection and inert sealing with respect to the rigid outer wall. Like the pipe, the coupling part (2) is made of a rigid joining outer sleeve (5) and a weldable socket (10), preferably made of the same material as the liner (1). Welding energy is introduced electrically. In order to cause a frictional connection on the one hand and a fluid-tight connection on the other between the two pipes, the inner pipe or liner projects beyond the outer part (3) by approximately half the length of the socket (10) at the joining point forming a free pipe end 9, which in the assembled state comes to rest in the electrically weldable socket (10). The outer sleeve on both ends of the coupling part (2) is shaped like a socket-like portion (6) so that following the introduction of the pipes into coupling part (2) it embraces the corresponding areas of the pipe outer sleeve. The full circumferences of free pipe ends (9) are welded in the vicinity of filament winding (12) and the coupling outer sleeve (5) is bonded frictionally to the pipe outer sleeve (3) in the vicinity of the socket-like portion.