Abstract: A method of spirally winding a thermoplastic profile in the manufacture of welded plastic tubes and a winding apparatus for manufacturing a spirally wound tube. A thermoplastic profile is received on a plurality of sliding members being arranged in an axial direction of the tube to be manufactured and defining an essentially cylindrically shaped winding surface with a diameter essentially corresponding to the inner diameter of the tube. The profile is directed along a spiral path towards the previous turn of the profile in order to force opposite edges of the profile together for welding. The radial position of the sliding member is adjusted to control the tension in the thermoplastic profile and the force with which it constricts itself around the winding surface as defined by the sliding member.

Abstract: A method and apparatus in the manufacture of a spirally wound and welded tube is disclosed. A thermoplastic profile is slid along a path on a slider arranged in an axial direction of the tube and defining a cylindrically shaped winding surface with a diameter corresponding to the inner diameter of the tube to be manufactured. The profile is directed along a spiral path towards a previous turn of said profile by means of radial rollers spaced along said spiral path by adjusting the position of the rollers: Opposite edges of said profile turns are welded together by providing an extruded welding mass between said profile turns. The welded tube is fed from the welding station by means the rollers by sliding it onto a rotating support.

Abstract: Device and connector tube for coating a pipe or portion of a pipe, which has an outer surface determined by the outer circumference of the pipe or portion of a pipe. The device includes a moving device, which can rotate around the outer surface of the pipe or portion of a pipe, and a coating nozzle, which is connected to a molten-polymer source in order to form a polymer film, which nozzle is attached to the device, which can rotate around the pipe. The feed tube forms at least part of the molten polymer's feed route from the source to the coating nozzle, which feed tube includes at least two rigid tubes and at least one connector, which includes at least two connector parts for connection to the tube and a bearing arrangement fitted between the connector parts, which permits the connector parts to rotate around their common longitudinal axis and keeps the connector parts parallel to each other.

Abstract: A method of spirally winding a thermoplastic profile in the manufacture of welded plastic tubes and a winding apparatus for manufacturing a spirally wound tube. A thermoplastic profile is received on a plurality of sliding members being arranged in an axial direction of the tube to be manufactured and defining an essentially cylindrically shaped winding surface with a diameter essentially corresponding to the inner diameter of the tube. The profile is directed along a spiral path towards the previous turn of the profile in order to force opposite edges of the profile together for welding. The radial position of the sliding member is adjusted to control the tension in the thermoplastic profile and the force with which it constricts itself around the winding surface as defined by the sliding member.

Abstract: A method and apparatus in the manufacture of a spirally wound and welded tube is disclosed. A thermoplastic profile is slid along a path on a slider arranged in an axial direction of the tube and defining a cylindrically shaped winding surface with a diameter corresponding to the inner diameter of the tube to be manufactured. The profile is directed along a spiral path towards a previous turn of said profile by means of radial rollers spaced along said spiral path by adjusting the position of the rollers: Opposite edges of said profile turns are welded together by providing an extruded welding mass between said profile turns. The welded tube is fed from the welding station by means the rollers by sliding it onto a rotating support.

Abstract: A hollow profile used in the manufacture of a spirally wound double-walled thermo-plastic pipe, having essentially a rectangular cross section, two side walls and an outer wall and an inner wall limiting a cavity within. In the hollow profile the inner wall of the pipe is thicker than the wall of the hollow profile intended to form the outer wall of the pipe. The inner rounding radius of the edges adjacent to the thicker wall of the hollow profile is considerably larger than the rounding radius of the two other edges of the cavity and the inside surface of the thicker wall comprises a rib extending in the hollow cavity of the profile, on the side of the profile forming the inner side of the pipe, in the longitudinal direction of the profile at least essentially along the whole length of the profile.

Abstract: Method and apparatus for coating a pipe or a pipe section with a layer of at least one polymer. The method includes providing the pipe or the pipe section having an outer surface defining the periphery of the pipe or the pipe section; applying on the outer surface of the pipe or pipe section a layer of at least one polymer material in melt stage using a nozzle, which is mounted on a carriage capable of travelling along the periphery of the pipe or the pipe section; and moving the carriage along at least a part of the periphery during the application of the polymer material to form a layer on the surface of the pipe or the pipe section that is particularly useful for coating field joints in pipelines.

Abstract: A hollow profile used in the manufacture of a spirally wound double-walled thermo- plastic pipe, having essentially a rectangular cross section, two side walls and an outer wall and an inner wall limiting a cavity within. In the hollow profile the inner wall of the pipe is thicker than the wall of the hollow profile intended to form the outer wall of the pipe. The inner rounding radius of the edges adjacent to the thicker wall of the hollow profile is considerably larger than the rounding radius of the two other edges of the cavity and the inside surface of the thicker wall comprises a rib extending in the hollow cavity of the profile, on the side of the profile forming the inner side of the pipe, in the longitudinal direction of the profile at least essentially along the whole length of the profile.

Abstract: Method and apparatus for coating a pipe (2) or a pipe section with a layer of at least one polymer. The method comprises providing a pipe (2) or a pipe section having an outer surface defining the periphery of the pipe or pipe section; applying on the outer surface of the pipe or pipe section a layer of at least one polymer material in melt stage using a nozzle (3), which is mounted on a carriage capable of travelling along the periphery of the pipe (2) or pipe section; and moving the carriage along at least a part of the periphery during the application of the polymer material to form a layer on the surface of the pipe (2) or pipe section. The outer surface of the pipe or pipe section is being locally heated by induction heating before the application of the polymer material onto said surface. The present invention is particularly useful for coating field joints in pipelines.

Abstract: This invention relates to a hollow profile (1) used for the manufacture of a spirally wound double-walled thermoplastic pipe, which hollow profile has essentially a rectangular cross section and the wall (2) of the hollow profile intended to form the inner wall of the pipe is thicker than the wall (4) intended to form the outer wall (4) of the pipe. The invention is characterized in that the inner rounding radius (7a) of the edges adjacent to the thicker wall (2) of the hollow profile is considerably larger than the rounding radius (7) of the two other edges of the cavity (6).

Abstract: Method and apparatus for coating a pipe (2) or a pipe section with a layer of at least one polymer. The method comprises providing a pipe (2) or a pipe section having an outer surface defining the periphery of the pipe or pipe section; applying on the outer surface of the pipe or pipe section a layer of at least one polymer material in melt stage using a nozzle (3), which is mounted on a carriage capable of travelling along the periphery of the pipe (2) or pipe section; and moving the carriage along at least a part of the periphery during the application of the polymer material to form a layer on the surface of the pipe (2) or pipe section. The present invention is particularly useful for coating field joints in pipelines.