A synthetic resin pipe for underground installation includes a synthetic resin strip which is spirally wound and joined to form an elongated pipe. The outer surface of this elongated pipe is smooth and continuous. Reinforcing ribs of the strip have hollow centers and protrude radially inwardly. Strip lateral extents which are adjacent to the reinforcing ribs are joined to form the smooth outer surface of the pipe and also to form an inner wall between adjacent reinforcing ribs.
A pressure-resistant helically corrugated pipe includes an integral, pipe wall corrugation helically wound to form a pipe, the corrugation having a trough portion disposed close to the axis of the pipe and outwardly projecting flange portions on opposite sides of the trough portion, adjacent flange portions being connected together to form the pipe having a helical outwardly projecting portion adjacent the trough portion. The pipe further includes a metal belt plate reinforcing member disposed within the trough portion of the helically disposed corrugation, the metal belt plate being generally U-shaped in cross-section so as to define a base, legs and free ends and opening toward the exterior of the pipe.
A plastic pipe having spiral ridges on an outer surface and a continuous, cylindrical inner surface formed by a spiral wound plastic ribbon having at least one ridge-shaped hollow deformation extending longitudinally of the ribbon and spirally of the pipe. The outer radial surface of the hollow deformations are slit and sealed with a ribbon. Side portions extend from the opposite sides of the hollow deformations and are fused to each other to form the cylindrical inner surface.
A large-caliber pipe consisting of thermoplastic, constructed from an extruded hollow plastic profile having helical turns welded along a helical contact seam. The hollow plastic profile is a multi-cell profile having a rectangular overall cross section and a rectangular cross section of the cells. The plastic has an integrated reinforcement consisting of embedded fibers in a quantity of 5 to 30% by weight, preferably about 10% by weight, based on the total weight. At least a proportion of the fibers is oriented in the direction of the turns. The orientation of the fibers results in an anisotropic modulus of elasticity and hence an increased annular rigidity and stability.
A pressure-resistant helical corrugated pipe comprises a helical corrugated pipe wall formed by a top portion, opposite side wall portions and a bottom portion; and a continuous thin metal belt plate disposed at least in the top portion or the bottom portion and also in part or the whole of the opposite side wall portions. The metal belt plate serves as a constituent element for the pipe wall. A portion of the metal belt plate disposed at the top portion or the bottom portion has one or more reinforcement ribs and a connective portion for the metal belt plate is integrally formed of a synthetic resin material or rubber material.
A synthetic resin pipe intended for underground use having an increased strength but reduced wall thickness. In accordance with the invention, a reinforcing member, in the form of a perforated belt, is embedded in or fused to the resin material of the pipe and extends along top portions and at least portions of the side walls adjacent to the top portions of the corrugations of the pipe.
