Tubular conduit
A tubular conduit ( 1 ) is disclosed. The tubular conduit comprises a tubular portion made from a flexible material and an axially extending external helical formation ( 16 ) located around the outside of the tubular portion. The external helical formation ( 16 ) is for supporting the tubular portion. Optionally the tubular portion also comprises an axially extending internal helical protrusion ( 15 ), which imparts a helical flow to a fluid passing through the tubular portion. It is preferred that the tubular conduit ( 1 ) is a vascular graft.
1. A tubular conduit comprising:
a tubular portion comprising an inside and an outside and being made from a flexible material;
an axially extending external helical formation located around the outside of the tubular portion for supporting the tubular portion; and
an axially extending internal helical protrusion located around the inside of the tubular portion for imparting a helical flow to a fluid passing through the tubular portion, having a different helix angle from the external helical formation;
wherein the axially extending internal helical protrusion comprises a section of the tubular portion deformed by an axially extending deformation helix;
wherein the external helical formation and the axially extending deformation helix are made from the same material; and
wherein an outer surface of the axially extending deformation helix is substantially flush with the outside of the tubular portion.
2. The tubular conduit according to claim 1 for use as a graft.
3. The tubular conduit according to claim 2 wherein the graft is a vascular graft.
4. The tubular conduit according to claim 1 wherein the axially extending deformation helix and the external helical formation are made from polyurethane.
5. The tubular conduit according to claim 1 wherein the axially extending deformation helix is sintered to the flexible material of the tubular portion.
6. The tubular conduit according to claim 1 wherein the helix angle of the external helical formation is greater than the helix angle of the internal helical protrusion.
7. The tubular conduit according to claim 1 wherein the helix angle of the internal helical protrusion is between 8° and 20°.
8. The tubular conduit according to claim 1 wherein the helix angle of the external helical formation is greater than 50°.
9. The tubular conduit according to claim 8 wherein the helix angle of the external helical formation is between 65° and 80°.
10. The tubular conduit according to claim 1 wherein the tubular portion is made from ePTFE.
11. The tubular conduit according to claim 1 wherein the inside of the tubular portion has a carbon coating.
12. The tubular conduit according to claim 1 wherein the external helical formation is sintered to the flexible material of the tubular portion.
13. The tubular conduit according to claim 1 , wherein the tubular portion is made from a fabric, wherein the fabric is a knitted woven or extruded polymer.
14. The tubular conduit according to claim 1 , wherein the tubular portion is made from polyurethane.
15. The tubular conduit according to claim 1 , wherein the tubular portion is made from a material selected from PTFE and ePTFE.
16. The tubular conduit according to claim 1 , wherein the external helical formation and the axially extending deformation helix are made from polyester.
17. The tubular conduit according to claim 1 , wherein the external helical formation and the axially extending deformation helix are made from PTFE.
18. The tubular conduit according to claim 1 , wherein the tubular portion is made from the same material as the external helical formation and the axially extending deformation helix.
19. The tubular conduit according to claim 18 , wherein the material is polyurethane.
20. The tubular conduit according to claim 18 , wherein the material is selected from at least one of ePTFE and PTFE.