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: 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.