Method for heated tool butt welding of tube and pipe of thermoplastic materials
AssigneeRuhrchemie Aktiengesellschaft
InventorsKlaus-Dieter Konrad, Rudolf Kellersohn, Hans Steck, Josef Schaub
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Abstract
In a method for heated tool butt welding of pipe consisting of a thermoplastic material by placing or pressing the surfaces to be joined of the pipes to be welded into contact with a heated tool to form an inner weld bead at each end to be joined, subsequently heating the surfaces at a reduced contact pressure to the welding temperature and fitting the surfaces together under pressure after having removed the heated tool, the improvement for minimizing the formation of a protrusion within the resultant pipes which comprises pressing an elastic insert against the inner weld bead while joining said surfaces of said pipe together.
Claims5
A process of forming a weld between abutting ends of thermoplastic pipes to be joined which comprises:
- (a) disposing at the point of abutment of said pipes and within said pipes and inwardly deformable elastic insert;
- (b) disposing between the ends of said thermoplastic pipe a heated tool such that the ends of said thermopastic pipe abut said heated tool;
- (c) heated tool projecting into said inwardly deformable elastic insert to inwardly deform and shape the same and to dispose a portion of said elastic insert away from the point of the weld to thereby reduce the pressure on the inside of said pipe at the point of the weld;
- (d) heating said ends by contact with said heated tool to a temperature sufficient to weld their respective ends to one another;
- (e) withdrawing said heated tool and fitting said respective ends to one another, whereby said elastic insert bears against and flattens a bead which forms at said weld;
- and
- (f) cooling the pipes while said elastic insert bears against the walls of said thermoplastic pipe at the weld.
Dependencies are inferred from the claim text.