A pressure-resistant helical corrugated pipe comprises a helical corrugated pipe wall; and two kinds of thin metal belt plates provided as a pipe wall-constituting element. The metal belt plates are disposed at least partially in overlapping relation in the direction of the thickness of the pipe wall. The overlapped portions of the metal belt plates are spaced from and held out of contact with each other by an intermediate resin layer, and the overlapped portions are integrally connected together by the intermediate resin layer. The pressure-resistant helical corrugated pipe is produced by forming the metal belt plates into a shape conforming to the corrugated shape of the pipe wall; subsequently applying a molten synthetic resin material to one or both sides of the metal belt plates along the entire length thereof to provide belt members with the molten resin material; and helically winding the belt members before hardening of the molten resin material in such a manner that the metal belt plates are partially overlapped so that the molten resin material serves as an intermediate resin layer which holds overlapped portions of the metal belt plates in spaced, non-contact relation to each other.
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; a wide metal belt plate of a thin metal plate disposed at least at the top portion and the opposite side wall portions; and a small width metal belt plate being separate from the wide metal belt plate and disposed at the top portion of the pipe wall in overlapping relation to the wide metal belt plate in the direction of the thickness of the pipe wall. The two metal belt plates are integrally connected together at an overlap portion by a synthetic resin material or a rubber material.
An object of the present invention is to provide a synthetic resin pipe configured to perform water stop accurately by forming a part connecting convex portions of an outer pipe to be flat without reducing flexibility in order to compose a synthetic resin pipe having flat inner and outer surfaces. A synthetic resin pipe according to the present invention includes an inner pipe formed by spirally winding a belt-like synthetic resin; a spiral reinforcing part formed by spirally winding a synthetic resin having a projected rim with convex portions projecting outside; an outer pipe of belt-like synthetic resin provided so as to connect a part or all of the convex portions arranged in a pipe axis direction; and a shape retaining material for the outer pipe made of a belt-like metal sheet for retaining a shape of the outer pipe flat and buried in or provide to an inner surface of the outer pipe; wherein the shape retaining material for the outer pipe is a synthetic resin pipe wound around the convex portions of the projected rim at predetermined intervals and connecting the convex portions of the projected rim.
A flexible conduit formed by a helically wound band of metal that resists burst pressure. The band has a leading edge hook and a trailing edge hook that engage and interlock. The cross-section of the band has a radially asymmetrical Z-shaped profile. When the band is helically wound, the downstream hook of one turn of the band is received in the upstream valley of the previous turn of the band so that the downstream and upstream hooks form an interlock holding the windings together. In the wound configuration, the thickness of the profile between the upstream valley and the internal surface of the tube is greater than the thickness of the profile between the downstream valley and the external surface of the tube to provide greater material thickness to reduce contact stress at the hook and valley interface and to reduce alternating stresses in the valley corners. The outer surface of the profile tapers towards the center of the tube to direct externally applied radial compression forces toward the thickest section of the profile. A multilayer conduit employing the band may include a central, helically wound collapse-resistant layer disposed within a flexible fluid barrier that in turn is disposed within the tube formed by the band. The conduit may be wrapped with one or more tensile strength layers, anti-wear layers, and additional fluid barriers.
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 constitent 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.
