Composite reinforced strip windable to form a helical pipe and method therefor

A composite strip windable to form a helical pipe for transporting fluid, the composite strip comprising:

• an elongate plastic strip having a base portion, the base portion having a lower side defining an inner face and an upper side defining an outer face;
• at least one lengthwise extending rib portion upstanding from the outer face of the base portion, the rib portion having a distal end remote from the base portion;
• an elongate inboard reinforcing member disposed within or adjacent to the base portion;
• first and second elongate outboard reinforcing members disposed within the distal end of the rib portion parallel to the inboard reinforcing member and positioned laterally offset to first and second sides respectively of a plane bisecting the rib portion perpendicularly to the base;
• and
• an elongate intermediate plastic web portion extending between the inboard and outboard reinforcing members, the web portion together with the inboard and outboard reinforcing members forming a composite rib portion,
• wherein, when wound into a helical pipe, the composite rib portion reinforces the pipe against radial crushing loads.

A pipe comprising a helically wound composite strip, the composite strip comprising:

• an elongate plastic strip having a base portion, the base portion having a lower side defining an inner face and an upper side defining an outer face;
• at least one lengthwise extending rib portion upstanding from the outer face of the base portion, the rib portion having a distal end remote from the base portion;
• an elongate inboard reinforcing member disposed within or adjacent to the base portion;
• an elongate outboard reinforcing member disposed within the distal end of the rib portion parallel to the inboard reinforcing member;
• and
• an elongate intermediate plastic web portion extending between the inboard and outboard reinforcing members, the web portion together with the inboard and outboard reinforcing members forming a composite rib portion,
• wherein the composite rib portion reinforces the pipe against radial crushing loads.

A method of producing a pipe comprising the steps of:

• a) extruding an elongate plastics strip, the strip having a base portion, the base portion having a lower side defining an inner face and an upper side defining an outer face, and at least one lengthwise extending rib portion upstanding from the outer face of the base portion;
• b) introducing a lower reinforcing member into the base portion of the strip in a position adjacent to the at least one rib portion so as to form a sub-assembled composite strip;
• c) winding the sub-assembled composite strip into a spool of strip or into a helically wound pipe;
• d) introducing an upper reinforcing member into a top portion of the at least one rib portion so as to form an assembled composite strip,
• whereby the step of introducing a lower reinforcing member occurs during or after the extruding step but before the winding step and whereby the step of introducing the upper reinforcing member occurs during or after the winding step.

A method of producing a pipe comprising the steps of:

• a) extruding an elongate plastics strip, the strip having a base portion, the base portion having a lower side defining an inner face and an upper side defining an outer face, and at least one lengthwise extending rib portion upstanding from the outer face of the base portion, the rib portion having a distal end remote from the base portion;
• b) introducing a lower reinforcing member into the base portion of the strip in a position adjacent to the at least one rib portion so as to form a sub-assembled composite strip;
• c) bending the composite strip about an axis transverse to the base;
• d) introducing an upper reinforcing member into the distal end of the at least one rib portion so as to form an assembled composite strip,
• whereby the step of introducing a lower reinforcing member occurs during or after the extruding step but before the bending step and whereby the step of introducing the upper reinforcing member occurs during or after the bending step.

A method of producing a pipe comprising the steps of:

• a) extruding an elongate plastics strip, the strip having a base portion, the base portion having a lower side defining an inner face and an upper side defining an outer face, and at least one lengthwise extending rib portion upstanding from the outer face of the base portion, the rib portion having a distal end remote from the base portion;
• b) introducing a first reinforcing member into either of:
• the base portion of the strip in a position adjacent to the at least one rib portion, or the distal end of the at least one rib portion so, as to form a sub-assembled composite strip;
• c) bending the composite strip about an axis transverse to the base;
• d) introducing a second reinforcing member into the other of:
• the base portion of the strip in a position adjacent to the at least one rib portion, or the distal end of the at least one rib portion so as to form an assembled composite strip,
• whereby the step of introducing a first reinforcing member occurs during or after the extruding step and whereby the step of introducing the second reinforcing member occurs during or after the bending step.