Butt-welding hollow thermoplastic profile - by heating the ends circumferentially, pressing contact faces together and pulling them slightly apart

摘要

Thermoplastics hollow profiles are butt-welded together by heating the entire circumference of frontal faces to be welded; fusing them whilst pressing them together; and then very slightly pulling them apart. Before the welding step, a hollow body which does not adhere to the melting plastics, and whose outer dia. is a little smaller than the inner dia. of the profiles to be welded, is introduced into both profile ends. A blocking device is inserted into one of the hollow profiles whilst a closure with a flexible hose is fitted into the other profile. After the 2 profiles have been pushed together, a reduced pressure is party or permanently generated inside the profiles. After the welded-together profiles have been pulled slightly apart, a slight superpressure is opt. set. up. Used in butt-welding of thermplastics pipes and tubes. Formation of circumferential welding rims or thick seams is minimised.