Tubular Conduit

Abstract

A tubular conduit is disclosed. The tubular conduit comprises a tubular portion made from a flexible material and an axially extending external helical formation located around the outside of the tubular portion. The external helical formation is for supporting the tubular portion. Optionally the tubular portion also comprises an axially extending internal helical protrusion, which imparts a helical flow to a fluid passing through the tubular portion. It is preferred that the tubular conduit is a vascular graft.

What is claimed is: 
     
         1 .- 39 . (canceled) 
     
     
         40 . A mould for providing a helical formation onto a tubular conduit comprising:
 a mandrel having an outer surface on which the tubular conduit is locatable, the mandrel having an axially extending helical channel on its outer surface; and   a moulding block having a bore for receiving the mandrel with the tubular conduit located thereon.   
     
     
         41 . A mould according to  claim 40  wherein the mandrel has an axially extending helical channel on its inner surface. 
     
     
         42 . A mould according to  claim 41  wherein the helix angle of the helical channel on the bore is different from the helix angle of the helical channel on the mandrel. 
     
     
         43 . A mould according to  claim 42  wherein the helix angle of the helical channel on the bore is greater than the helix angle of the helical channel on the mandrel. 
     
     
         44 . A mould according to  claim 40  wherein the helix angle of the helical channel on the mandrel is between 8° and 20°. 
     
     
         45 . A mould according to  claim 41  wherein the helix angle of the helical channel on the bore is greater than 50°. 
     
     
         46 . A mould according to  claim 45  wherein the helix angle of the helical channel on the bore is between 65° and 80°. 
     
     
         47 . A mould according to  claim 40  wherein the tubular conduit is a vascular graft.