METHOD AND EQUIPMENT FOR DETERMINING QUALITY OF JUNCTION OF THERMOPLASTIC RESIN TUBE

PROBLEM TO BE SOLVED: To properly determine the quality of a state of junction in a method wherein a joint being a short tube is disposed between tubes to be joined together. SOLUTION: There are provided a process wherein a tubular joint 3 is disposed between a first thermoplastic resin tube 1 and a second thermoplastic resin tube 2 to be joined together and, by rotating the tubular joint 3 around the tube axis in a state wherein the joining end faces of the tubes are brought into contact with each other, a frictional heat is generated in each joining end face, so that melting of each joining end face be started and continued, and a welding process wherein the joining end faces of the first and second thermoplastic resin tubes 1 and 2 are pressure-welded after the rotation of the tubular joint 3 is stopped and the joint 3 and each of the resin tubes 1 and 2 are welded together by the pressure welding. There is also provided a process wherein the amount of relative movement of the first resin tube 1 and the joint 3, the amount of relative movement of the second resin tube 2 and the joint 3 and a difference between these amounts of relative movement in the welding process are determined and it is judged whether these three values are within the ranges of preset reference values. COPYRIGHT: (C)2003,JPO