Method and apparatus for winding a liner inside a host pipe

Abstract

The invention provides methods and apparatus for producing a spirally wound pipe or pipe liner, and also to a web for forming a spirally wound pipe or pipe liner. One aspect of the invention provides a method and an associated machine of winding a helically wound pipe from a web (200) having transversely spaced apart connecting formations (310, 320) adapted to interlock when the web is wound in a helical path and adjacent edge portions (300a. 300b) of the web overlap one another, wherein an exterior support means (400) for the connecting formation at the terminus of the pipe being helically wound from the web is provided, and a radially outwardly directed force is applied against an inner face (220) of the web and the support means (400) to pinch connecting formations into interlocking engagement. A further aspect of the invention provides an elongated web (200) comprising a wall portion (210) bound by edge portions (300a. 300b) and adapted to form a pipe by spirally winding said web and joining adjacent said edge portions, wherein a distal end of joined edge portions (330) of the web projecting from the wall portion (210) of the web is less than a spacing distance defined by a spacer rib (350) projecting from the wall portion, when the web is spirally wound and adjacent edge portions are joined together.

Claims

1. A machine for winding a helically wound pipe from an elongated web, said web comprising a wall having complementary connecting formations extending along opposing edge portions thereof and which are adapted to interlock when the web is wound in a helical path and adjacent edge portions of the web overlap one another, said machine comprising: a frame having circumferentially spaced guide rollers adapted to bear against an inner periphery of the pipe being wound, the circumferentially spaced guide rollers forming a guide to enable the web to follow a helical path along which the web is directed when the machine is in use; web drive roller means mounted to the frame for driving/pulling the web around the outside of the rollers; drive means mounted to the frame for driving the web drive roller means, wherein the web drive roller means is located wholly inside the helical path; an exterior support means for supporting an outer face of the web; means for applying a radially outwardly directed force against an inner face of the driven web and the exterior support means, thereby pinching the overlapping connecting formations into interlocking engagement; wherein said wall of said web includes at least one spacer rib projecting therefrom; a distal end of said spacer rib defining an outermost diameter of the pipe being wound; wherein the distal end of the spacer rib and the wall define a spacing distance; and wherein said spacer rib and said exterior support means are respectively dimensioned such that as the pipe is wound said exterior support means is wholly located within said spacing distance.

2. The machine according to claim 1 wherein the distal end of the spacer rib and the wall define a spacing distance, wherein the said exterior support means is wholly located within said spacing distance as the pipe is wound.

3. The machine according to claim 1 wherein said means for applying a radially outwardly directed force comprises a roller biased in a radially outward direction.

4. The machine according to claim 1 wherein said exterior support means is a support plate.

5. The machine according to claim 1 wherein said exterior support means is a support plate, said support plate including a support face over which the outer face of the web passes as the liner is wound.

6. The machine according to claim 1 wherein said exterior support means directly supports the web at the point of connection of the overlapping connecting formations.

7. The machine according to claim 1 wherein said overlapping connecting formations comprise complementary male and female locking formations.

8. The machine according to claim 7 wherein an outer face of the female locking formation is directly supported by the exterior support means.

9. The machine according to claim 7 wherein a support face of the exterior support means includes a complementary recess which receives and supports the outer face of the female locking formation.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) One or more preferred embodiments of the present invention will now be described, by way of example only without limitation, with reference to the accompanying drawings in which:

(2) FIG. 1 is a diagrammatic view of a conventional installation system for spirally wound pipes;

(3) FIG. 2 is front view of the machine of the invention showing a spirally wound pipe and an incoming section of web and the entry angle between the incoming section and the terminal end of the pipe;

(4) FIG. 3 is a transverse cross-sectional view of two lengths of joined web according to the invention is shown;

(5) FIG. 4 depicts a transverse cross-sectional view of two sections of joined web and illustrates a further preferred embodiment of the web;

(6) FIG. 5 is an illustrative perspective view of the machine of the invention together with partially wound web as shown in FIG. 3, and showing exterior and interior support means for pinching overlapping connecting formations of the web into interlocking engagement; and

(7) FIG. 6 is a perspective view of the machine depicted in FIG. 5, depicting the inner and outer support means for pinching overlapping connecting formations into interlocking engagement.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

(8) The present invention will now be described with reference to the following examples which should be considered in all respects as illustrative and non-restrictive.

(9) FIG. 3 depicts a transverse cross-sectional view of two sections of joined web 200 according to the present invention. The web 200 has a constant cross section along its length and is preferably extruded from a suitable polymer material such as, for example, PVC. The web 200 can take a range of sizes and thicknesses in order to provide a liner with sufficient stiffness to meet the specific design requirements of the installation.

(10) The web 200 comprises a substantially planar wall portion 210 bounded by opposing first and second edge portions 300a, 300b. The opposing edge portions 300a, 300b of each web feature a male locking formation 310 and a complementary female locking formation 320. As the web is spirally wound adjacent edge portions 300a, 300b of the winding are joined by the interlocking of the complementary male and female connecting formations to form a continuous connection 330.

(11) The wall 210 of web 200 has a first, substantially planar, face 220 which in use forms the bore of the liner. The wall 210 has a second face 230 which includes at least one spacer rib 350 projecting transversely therefrom. The spacer ribs 350 have a generally T shaped profile, with an outer bearing surface 360 provided at the distal end of the rib. In use, the second face 230 forms an outer face of the wound liner, with ribs 350 extending from the outer face. The distal ends of the ribs 350 define the outer diameter of the wound liner. The bearing surfaces 360 of the ribs 350 seating against the bore of the pipe being lined and are in intimate contact with the bore around the entire periphery of the liner.

(12) The distal end of the spacer rib 350 and the wall portion define a spacing distance X, wherein the edge portions 300a, 300b and spacer ribs 350 are configured such that when said web 200 is spirally wound and adjacent edge portions 300a, 300b are joined together to create interlocked edge portions 330, the distal end of the joined edge portions 330 project from the wall portion 210 less than the spacing distance (distance Y) defined by the spacer rib 350.

(13) It will be appreciated that the spacer rib 350 projects a certain distance X from the wall portion 210, and that the locking edge portions are configured to project a certain distance Y from the wall portion when locked together, and the web is configured such that since X>Y (i.e. the rib is taller than the locked edge portions) a residual space Z is provided within which to accommodate an external support means 400. Advantageously this enables the external support means 400 to be used in situ to pinch the edge portions 300 together into locking engagement and enables the pipe to be formed with no annular space between the distal ends of the ribs and the host conduit/pipe. Provision of an external support means 400 enables large diameter pipes to be wound and to more reliably lock the edge portions 300 together into locking engagement.

(14) The external support means 400 preferably takes the form of a fixed plate 420. The plate includes a support face 430 over which an outer face of the web passes as the liner is wound. The external support means 400 directly supports the web at the point of connection of the male and female locking formations, with an outer face of the female locking formation 320 being directly supported by the fixed plate 420. In the embodiment depicted in FIG. 3 the support face 430 of the fixed plate 420 includes a complementary recess which receives an outer face of the female locking formation 320 and directly supports the web at the terminus of the pipe being wound.

(15) The outer faces 360 of the spacer ribs 350 define the outer diameter of the pipe or liner being wound. In accordance with the invention, the plate 420 is located wholly within the outer diameter of the pipe or liner being wound. In this way, intimate contact can be created between the liner and the bore of the host pipe around the entire diameter of the liner.

(16) FIG. 4 depicts a transverse cross-sectional view of two sections of joined web 200, and illustrates a further preferred embodiment of the web 200. This embodiment the web 200 includes a helix compensation zone 370 which permits said web to expand or contract laterally in order to compensate for helix changes in the pipe.

(17) As a result, the helix compensation zone 370 enables the width of the web to vary in response to lateral forces. Advantageously, the expansion or contraction of the web provides for helix compensation. As the diameter of the pipe being wound varies so also does the helix angle. Advantageously, the incorporation of a zone of compensation in the wall of the web means that the winding machine does not need to compensate for the helix and hence enables the machine greater degree of flexibility when winding pipes of varying diameters.

(18) In preferred embodiment depicted in FIG. 4 the helix compensation zone takes the form of a generally U-shaped wall section 380 immediately adjacent the female locking formation 320. However it should be appreciated that the compensation zone may be located in other locations in the wall 210 of the web and make take other cross-sectional forms such as, for example, a W-shape. Similarly, the web 200 may incorporate more than one compensation zone.

(19) The invention also relates to a method of winding a helically wound pipe from a web 200 having connecting formations 300 spaced apart transversely on the web 200 and adapted to interlock when the web 200 is wound in a helical path and adjacent edge portions 300 of the web overlap one another. The method comprises the steps of feeding the web in a substantially axial direction with respect to the axis of the pipe being wound and driving the web around the outside of a plurality of circumferentially spaced guide rollers (not shown) arranged to form a guide to enable the web to follow the helical path. An exterior support means 400 is provided for the connecting formation at the terminus of the pipe being wound. A radially outwardly directed force is applied against the driven web 200 and the support means 400, thereby pinching the overlapping connecting formations into interlocking engagement.

(20) It will be appreciated that the radially outwardly directed force is preferably applied directly against the support means, with the driven web therebetween.

(21) FIG. 5 is an illustrative perspective view of the machine of the invention together with partially wound web 200 as shown in FIG. 3, showing the configuration of the inner and outer support plates. For ease of illustration the ribs 350, 355 and connecting formations 310, 320 on the web 200 have been omitted. The exterior support means 400 takes the form of a fixed plate 420 over which the connecting formation at the terminus of the pipe slides and which acts as a rigid support to enable the connecting formation of the driven web 200 to be pinched together. As described above with reference to FIG. 3, the face of the support plate 420 may be profiled so as to be complementary to the web.

(22) It will be appreciated that the combined action of the exterior support means 400, which is configured to be radially opposite an interior support surface 500, provides a net compressive force on the overlapping edges of the web 200 to interlock the overlapping edge portions together. In an alternative embodiment the exterior support means could be a roller positioned exterior to the connecting formations of the pipe being wound and or the interior compression roller can be a support plate.

(23) In other embodiments, one or more of the ribs adjacent to the edge portions 300 could be an equivalent height as the joined edge portions in order to accommodate a wider support surface 400. For example, referring to FIG. 3 it can be seen that one of the ribs 355 is relatively reduced in size compared to the others 350 in order to accommodate a wider support surface, such as a roller.

(24) The invention also relates to a machine for winding a helically wound pipe from a web 200 having complementary connecting formations 300 extending along opposite edge portions thereof and which are adapted to interlock when the web is helically wound. The machine comprises a frame (not shown) having circumferentially spaced guide rollers (not shown) adapted to bear against the inner periphery of the pipe being wound. The rollers form a guide to enable the web to follow a helical path along which the web is directed when the machine is in use. The machine also comprises web drive roller means (not shown) mounted to the frame for driving the web around the outside of the rollers so as to follow the helical path and cause the adjacent edge portions of adjacent convolutions of the web 200 to interlock. An external support means 400 and an internal support means 500 is provided and configured to bear against the locking members of the pipe being wound to cause the interlock of the adjacent edge portions of the web, as discussed above.

(25) FIG. 6 provides an enlarged view of the outer and inner support means 400, 500.

(26) The outer support means takes the form of a fixed plate 420. The plate 420 directly supports the web at the point of connection of the male and female locking formations. Plate 420 includes a finger 440, with an outer face of the female locking formation 320 directly supported by a complimentary support face 430 provided on finger 440. Support face 430 includes a complementary recess which receives an outer face of the female locking formation 320 and directly supports the web at the point of connection of the male and female locking formations.

(27) Inner support means 500 takes the form of a guide plate 510. The guide plate 510 has a support face 520 over which the inner face 220 of the web passes. The support face 520 is inclined with respect to support face 430 so as to form a progressively converging zone 600 between the inner and outer support means. This progressively converging zone 600 is shaped substantially in the form of a V and creates a nip point 610 whereby the progressively converging plates cause the connecting formations of the driven web to be forced into interlocking engagement with the connecting formation at the terminus of the pipe being wound.

(28) In accordance with the invention the outer support means 400 in the form of fixed plate 420 lies wholly within the outer diameter of the pipe being wound. As discussed above with reference to FIG. 3, this is achieved by the incorporation of spacer ribs 350 in the exterior face 230 of the web. The distal ends of the spacer ribs define the outer diameter of the pipe being wound. The spacer ribs 350 and the support plate 420 are respectively dimensioned such that support plate lies wholly within the spacing distance defined by the distal end of the spacer rib 350 and the exterior face 230 of the web.

(29) Advantageously, the present invention enables the formation of a liner pipe that can be in intimate contact with the host pipe by using a winding machine that has an external pressure (compression) means or support surface located on the outside of the connecting formations of the liner pipe. Moreover, the ability to position a support surface within a small space between the connecting formations and the host pipe provides the benefit of being able to wind at large diameters reliably and without the need to have a relatively stiff web. Other technologies may employ an external pressure means however the liner cannot be produced such that it is in intimate contact with the host pipe.

(30) The person skilled in the art will understand that the inventive method and apparatus may be embodied in forms other than that specifically described herein without departing from the spirit or scope of the present invention.