METHOD OF AND MEANS FOR FORMING AND SEALING HELICALLY WOUND TUBES.

摘要

PCT No. PCT/AU85/00009 Sec. 371 Date Oct. 10, 1985 Sec. 102(e) Date Oct. 10, 1985 PCT Filed Jan. 22, 1985 PCT Pub. No. WO85/03755 PCT Pub. Date Aug. 29, 1985.A strip adapted to form a tube by helically winding and having a series of longitudinal ribs upstanding from a base on the strip and transversely spaced thereon in which one rib has a bulbous end portion and another has a bulbous longitudinal socket to form interengaging means when helically wound, all or some ribs optionally defining a hollow whereby limited lateral stretch at the join and ribs is permitted. The hollow can be closed by a flap. In various embodiments the ribs take a number of forms. In most cases all ribs are hollow and of substantially rectangular or semicylindrical shape to give a corrugated external form. A panel formed by winding a strip to helical form and splitting the strip longitudinally and straightening it at least partially to form a draining wall is also described.