Abstract: A pre-press tube is composed of several lengths of tube with a plug-in end at one end and a plug-in socket at the other opposite end. Plug-in end and plug-in socket are chosen to be conical in such a way, that when the plug-in end is pressed into the plug-in socket, not only a form - and force locking arrangement is obtained, but even a tight connection of the material by means of a lattice like polymerization of the contact surfaces is obtained. As a result a tight, solid connection of tubes with a smooth surface is achieved.

Abstract: A method of manufacturing drain pipes comprises extruding a strip from an extruder into a plasticized strip form, winding the extruder strip into a continuous spiral of successive coils, joining the lateral edges of the successive coils, and perforating the plasticized strip. The strip is advantageously perforated after it is extruded and before it is wound. An apparatus for effecting the formation of drain pipe comprises an extruder for extruding the plasticized continuous strip onto a winding drum as the drum is continuously wound and the strip is advanced along the drum to form successive spiral forms which has means for welding the lateral edges of the coils of the strip and including a rotable disc member having circumferentially spaced projectings which rotates adjacent the winding drum and perforates the extruded sheet as it is formed.

Abstract: A heatable winding drum construction for use in the manufacture of thermoplastic tubes and receptacles comprises an internal supporting structure for an elongated cylindrical wall with an insulating layer between the supporting structure and the wall.

Abstract: A method of testing a weld joint interconnecting two thermoplastic parts comprises forming a sealed cavity around the weld joining the parts and applying a predetermined test pressure to the cavity to determine if there is any leakage thereof. The device of the invention comprises an additional wall structure which defines a seal cavity around the weld joining two thermoplastic parts and which is advantageously made by an additional weld or welds which forms the test cavity surrounding the welded joint to be tested.

Abstract: A device and method for producing a tube comprises a rotatable mandrel over which the tube is formed and an extruder alongside the mandrel having a nozzle which extrudes a supporting material having a hollow portion onto the mandrel at a selected angle in a manner to form a continuously helically wound strip on the mandrel as the mandrel is rotated and the mandrel and the extruder are moved relatively in respect to the longitudinal axis of the tube. A supply of a profiled material such as a tubular reinforcement is provided alongside the mandrel and advantageously comprises a reel supply over which the tube is wound and which is connected through a feeder in the form of upper and lower rollers which engage the profiled material and feed it through the extruder into association with the supporting material and into the hollow portion thereof.

Abstract: A device for producing a helically wound tube comprises a rotating mandrel around which the tube is wound and an extruding device having an extruder head oriented to direct a continuous strip of plastic through a profile pressure mandrel which defines a calibrating guide channel which in turn is oriented to deposit the desired width of extruded plastic strip onto the mandrel. The guide channel advantageously includes walls defining a cooling passage for a coolant for example on the wall over which the extruded plastic is directed. The extruder and the guide channel are mounted on a carriage so that they may be shifted longitudinally if the axis of the mandrel apply a continuous strip of material thereover at a selected pitch angle. The extruder advantageously includes means for directing a reinforcing rod member into the extruder head so that the extruded strip includes a central tubular reinforcement with a base flange on each side of the reinforcement.

Abstract: A device is disclosed for cooling or cooling and calibrating a ribbed tubular wall of a thermoplastic material in a deformable state in which the tubular wall has a circular surface and helically extending rib turns projecting from the circular surface at spaced intervals. A cooling chain of a plurality of interconnected cooling cells is mounted between at least two adjacent rib turns, a flexible cooling conduit interconnects the cells which are adapted to pass a coolant therethrough for cooling the adjacent rib turns, and the cells have wall portions contiguously into engaging the adjacent rib turns.

Abstract: A container, particularly one made of synthetic material or steel, compri a cylindrical container shell with a bottom or end closing each end of cylindrical shape and each end closing portion having a longitudinal axis extending perpendicular to the longitudinal axis of the shell. The closing end portions comprise half cylinders having diameters equal to the diameter of the cylindrical shell.