Abstract: Thermoplastic tube part provided with a polyurethan foam layer with closed skin and containing an inorganic filler for reducing sound production during flow of water through such tube parts.

Abstract: A plastic pipe of a thermoplastic material, such as polyvinylchloride provided on its outside with a resilient sealing body of a polyurethane foam plastic, which has been foamed onto said outside and a layer of thermosetting resin with electrically conducting particles being between said body and the plastic pipe in order to ensure a proper conduction, the foam plastic body having a closed surface being integral with the foam plastic body.

Abstract: A heat sealed or welded pipe connection for thermoplastic pipes comprises a male pipe part which is sealed to the inner surface of a female pipe part, said female pipe part carrying centering abutment projections on its outer surface. The female pipe part may consist of a socket which starting from its openings has an outer circumference with an increasing size, the outside radius of curvature of the socket is 6 to 12 times the outside diameter of the male pipe part and the total length of the socket is equal to the outside diameter of the male pipe part.

Abstract: A tube of thermoplastic material is heated to plasticity, whereupon the heated tube is provided with a thickened end by subjecting the tube to an upsetting action in such a way that the thickening starts at a distance from the free end of the heated part and increases gradually from this point towards the free end of the heated part.

Abstract: Sealing member for a spigot and socket coupling, comprising a retaining part, a sealing part extending with two steps within the space bound by the inner circumference of the retaining part and of the extension thereof and a connecting part interconnecting the retaining part and the sealing sleeve. At any point between the junction with the retaining part and the free end of the sealing sleeve, the thickness of the sealing member is not greater than the thickness of the part extending between said point and said junction. The thickness does not exceed the thickness of the sealing member at said junction.The inner side of the steps of the sealing member are provided with leakage-preventing ribs and the retaining part is substantially perpendicular to the connecting part, whilst the first step of the sealing sleeve is situated within the inner side of the retaining part. The end of the sleeve is provided with a tapered lip forming preferably a sort of sickle with the sealing member.

Abstract: A device for manufacturing a plastic tube having a thickened socket end and being provided with an inner circular groove. The device includes a socket forming mandril having a core member associated with it. The mandril is provided with a groove-forming member. A hollow die is also provided which has a portion adapted to fittingly cooperate with the outer side of the mandril. A hollow mould lies in an adjoining relationship with the hollow die and is disposed in front of the core member. The hollow mould has an inner diameter which is greater than the outer diameter of the mandril.

Abstract: A conducting plastic pipe system comprising a male plastic pipe part and a female plastic pipe part with conducting covering layers which are interconnected by means of a conducting sealing ring between the male and female part. In case of outer covering layers on the pipe part the covering layer extends onto the inner side of the muff end of the female pipe part.

Abstract: A pipe having an outer coating of foam plastics, a tape of thermoplastics being wrapped around the foam plastics in an overlapping way, the overlapping parts being heatsealed to each other. At least one reinforcing filament is present on the original contacting surfaces of the overlaps. Preferably one straight and one zig-zag applied filament are present.

Abstract: A process for perforating plastic tubes, in particular thin-walled corrugated tubes, by a punching or cutting operation wherein the plastic tubes are subjected to a direct or indirect treatment by a cooling fluid prior to the punching and cutting operation. The process is performed by an apparatus comprising a guide structure and conveying device for conveying the plastic tubes, and further comprising punching or cutting members, while spraying devices are provided for effecting the above-mentioned cooling treatment.

Abstract: A branch piece for pipe branch connections comprising two parts. The first part is provided with two longitudinal edges extending parallel to the axis of the branch pipe, and the other part is provided with one longitudinal edge which can be coupled with one of the longitudinal edges of the first part. The second longitudinal edge of the other part tapered. A separate wedgelike connecting member has two lips each adapted to engage with a longitudinal edge of the first part and of the second part.

Abstract: A method for manufacturing perforated plastic pipes, in particular corrugated thermoplastic pipes of which the wave valleys are perforated by at least one punching member, to which a velocity is imparted in the direction of conveyance of the plastic pipes, which equals the rate of conveyance of these pipes. During the punching operation the punching member or members retain substantially a perpendicular position with respect to the plastic pipes.

Abstract: A thermally insulated pipe particularly destined for mining industries, comprising an outer and an inner pipe, whereinbetween an insulating layer is arranged, the outer pipe being made of a synthetic material. The surface of the outer pipe is provided with an outside surface layer, being electrically conductive, which layer is connected with the inner pipe in an electrically conducting manner. The insulating material inbetween the two pipes is heat resistant.

Abstract: Plastic bags are obtained from a tubular foil of thermoplastics by means of heatsealing. The heatsealing member acts upon a lower wall of the flattened non-tensioned tubular foil, and without a counter pressure to the upper wall of the foil. The entire thickness of the lower wall is plasticized but only a portion of the thickness of the upper wall is plasticized. The assembly of heated lower wall and partly heated upper wall facing each other is passed through two pressure rolls, the roller surface contacting the surface which has not been in contact with the heat sealing member consisting of metal is cooled.

Abstract: An extruder for synthetic material is disclosed which includes an extruder housing provided with at least two worm conveyer shafts, each having one or more helices thereon. An inlet opening is provided in the housing at the extruder input for introducing the synthetic material and a degassing outlet is provided in the housing downstream of the inlet. Intermediately of the material inlet and degassing outlet, distributing members are arranged on the worm shaft peripheries, the distributing members comprising intermeshing tooth-shaped heightened parts of generally hemispherical configuration.

Abstract: A device for manufacturing corrugated plastic tube by subjecting an internally unsupported corrugated plastic tube, at a temperature between 30.degree. and 70.degree. C, to the simultaneous action of at least two punching members in one or in two corrugations.A device comprising a guide for corrugated plastic tube, and punching means with an operating member for simultaneously acting upon at least two punching members spaced a short distance from each other.

Abstract: Plastic bags are obtained from a tubular foil of thermoplastics by means of heatsealing. The heatsealing member acts upon a lower wall of the flattened non-tensioned tubular foil, and without a counter pressure to the upper wall of the foil. The entire thickness of the lower wall is plasticized but only a portion of the thickness of the upper wall is plasticized. The assembly of heated lower wall and partly heated upper wall facing each other is passed through two pressure rolls, the roller surface contacting the surface which has not been in contact with the heat sealing member consisting of metal is cooled.

Abstract: Method for automatically removing a synthetic resin article from the die of an injection moulding machine, whereby this article during the time that the die halves are in the open position, is removed and conveyed into a particular direction by a grab, whereupon a lateral transfer and supporting member discharges the article.

Abstract: A pipe connection for plastic pipes particularly fiber reinforced synthetic pipes made of thermosetting resin, comprising a female pipe part with a widened end of which the inside tapers from the free end and adjoins a longitudinally extending recess in the inner wall of the female pipe, the male pipe part having a protruding part adapted to this recess and having a first end face that on its end adjoins a conical end face which is adapted to the conical shape of the inside of the aforementioned widening, and a glue layer extends from the inside of the pipe connection as far as the outside of the male pipe part. Preferably the protruding part consists of an inner, chemically resistant, layer of a fiber reinforced synthetic resin pipe, which on its outside carries a fiber reinforcement and the inner side of the conical widening has a greater inner circumference which is considerably greater than the outer circumference of the male pipe part.

Abstract: Apparatus for continuously producing seals in tube-shaped plastics film material, comprising means for supplying the web of material, at least one heating beam travelling along with the web and subsequently returning, means for keeping the web mechanically tension-free at the location where it is warm, means for keeping the heated film layers one against the other up to a pressing station, said pressing station comprising two rollers at least one of which is provided with cooling means, and means for discharging the web. A plurality of heating beams being provided which are interconnected by flexible and longitudinally adjustable means such as belts so as to form an endless loop which is guided over and driven by appropriate adjustable tensioning rollers.