Abstract: This invention relates to improvements to reinforced ribbed structures, and in particular to reinforced or strengthened spirally wound pipes or tubes made from composite materials.

Abstract: The invention relates to apparatus for helically winding pipes from tube forming plastics strip comprising a single fixed rigid loop formed from a length of metal band, wherein the inner surface of the loop forms a spiral path along which the strip is directed when helically wound, strip guide means for guiding the strip into the path of the loop, and driven roller means for driving the strip around the spiral path and for joining together adjacent edges of adjacent convolutions of the strip, whereby during the helical winding process, the strip is driven around the spiral path in frictional engagement with the loop inner surface, maintaining intimate contact therewith, to thereby form the pipe.

Abstract: A method and means of slip control for helically wound pipes wherein the pipe is formed by helically winding a strip of plastics material and the edges of the convolutions of the strip are interconnected, wherein a slip-control member applied to the interconnected edges of the convolutions of the strip is arranged to be withdrawable progressively from the pipe to allow slip linearly between the interconnected edges of the convolutions of the pipe when torque is applied to the pipe.

Abstract: A method for protecting conduits in which a tube produced by helically winding a strip and interconnecting the edges of the strip to allow longitudinal slip is placed adjacent the area to be lined or overlapped. The tube is held at a selected diameter during placement and a winding force is applied by expander means driven along the tube to cause the interconnected edges to slip progressively change the diameter of the tube to engage the conduit. The progressive change may be caused by continuing the step of winding.

Abstract: The method of reinforcing a structure formed by interengaging the edges of ribbed strip (1) formed of a plastics material to form a helically wound tube, the strip (1) comprising a plurality of the ribs (2) spaced apart and upstanding from a base (24), characterized by engaging on the strip (1) a non-planar reinforcing member (10), and locking the reinforcing member (10) to the strip to form an attached strength member to attain lateral stability of the ribs.

Abstract: 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.

Abstract: A machine for forming helically wound pipes from a strip (15), having interengaging means on its longitudinal edges, in which a series of rollers (2 and 3) is positioned to form an annulus of rollers (2 and 3) arranged to curve the strip (15) to a helical form within the annulus with the edges of the strip (15) overlapping and means (18, 19) to press the interchanging means on the overlapping edges together to form a pipe (5), in which a pair of feed rollers (16, 17) remote from the means to press (18, 19) controls the rate of feed of the strip (15) to maintain the strip (15) between the feed rollers (16, 17) and the means to press (18, 19) in tension. A modification drives all of the rollers of the annulus synchronously.

Abstract: The formation of tubular objects by spirally winding and seaming a relatively rigid strip of plastics material. A sealing flap (15, 215) along one longitudinal edge (5, 25) of the strip, and an engaging surface (16, 216) along the other edge (11, 211) positioned close to but separate from the interlocking portions (8 and 12, 28, 212) of these longitudinal edges. The provision of these sealing flaps and engaging surfaces permit the interlocking portions at the edges to be designed independent of the ability of these interlocking portions to create a fluid seal. This results in optimum operation of these interlocking portions to, for example, permit relatively rapid changes in the diameter of the tube as it is formed, as well as subsequent to its formation.

Abstract: The method of forming tubes from strip in which a complementary rib and groove are spaced apart to each extend longitudinally on the strip and oppositely facing on the said strip characterized by guiding the strip into a helical configuration to overlap the edges of the said strip, and pressing together the overlapping parts of the said strip while maintaining a differential pressure in the direction of feed to force the strip together under such differential pressure.

Abstract: The method of forming tubes from strip in which a complementary rib and groove are spaced apart to each extend longitudinally on the strip and oppositely facing on the said strip characterized by guiding the strip into a helical configuration to overlap the edges of the said strip, and pressing together the overlapping parts of the said strip while maintaining a differential pressure in the direction of feed to force the strip together under such differential pressure.

Abstract: A conduit for drip irrigation systems having a wall of a pierceable material characterized by a series of inwardly formed dimples along the length thereof and arranged to be pierced by a piercing member on an off-take or sprinkler, the dimples having a selected wall thickness in relation to the wall of the conduit, the conduit being optionally provided with ribs at the dimples to give further securing means and optionally including a tension wire or member for support.

Abstract: An irrigation device with variable flow control which is arranged to give either a drip feed through an elongated helical channel or a sprinkler feed through a direct outlet to a sprinkler and acts as a valve to shut off flow also by turning a key within a body to locate relevant passages.