Abstract: An insulating pipe part of thermoplastic material comprises two opposite sections and one third section disposed at an angle with respect to the former sections, the wall portion of said sections being provided with a continuous wall cutting slit. The pipe part may comprise thicker parts of a polyurethan foam.For forming an insulated branch pipe joint, said insulating pipe part is pushed over a branch pipe and subsequently plastic sleeves with beveled front ends are heatshrunk on to said sections, thereby closing said slit in a moisture tight manner.In order to obtain a reliable moisture tight closing, the sleeves are provided with beveled front ends so that the lower sleeve ends overlap each other.

Abstract: The invention relates to a coupler for insulated plastic pipe ends and a branch pipe end, the insulation being covered with tubular casings. The coupler is provided with anchoring means comprising one or more ribs or cams extending laterally from the central coupler 1 and with means for transmitting pressure forces from the anchoring means and the central coupler to the tubular casings.

Abstract: A pipe part comprising an abutment-edge and a retaining ring being interconnected by means of retaining strips or dumb-bells which dumb-bells or strips will yield under a load without breaking. The pipe part consists of a polyolefin, preferably a polypropylene.

Abstract: A branch piece for pipe-lines comprising a first part and a second part for forming a cylindrical housing, each of the two parts being provided with a coupling edge for engaging a connecting or closing part. The parts are provided with wedge-shaped tongues which fit in complementary wedge-shaped recesses in the other parts.