SAETT OCH ANORDNING FOER ATT MED VARANDRA GENOM VAERMESVETSNING FOERENA TVAO ROERFORMADE ELEMENT

摘要

A method of joining together by heat welding two tubular elements of a meltable thermoplastic material. The elements are arranged so that one tubular element receives one end of the other element in a telescoping manner to form an annular space between the two elements. A welding sleeve of a meltable thermoplastic material is positioned in the annular space between the two tubular elements. Heating elements are also arranged in the annular space for heating and welding the welding sleeve to the surfaces of the two tubular elements. Additionally, a ring-shaped body which becomes enlarged when heat is applied thereto is positioned in the annular space between the two tubular elements and the heating elements are arranged on the outer surface of the ring-shaped body. The two tubular elements and the welding sleeve are pressed together by the force exerted by the ring-shaped body whose material shape is changed from a state in which it is originally dimensionally stable in heat to a state in which it is dimensionally unstable in heat.