Components for medical circuits
Condensation or “rain-out” is a problem in medical circuits and previous attempts to manage and/or prevent rain-out have resulted in relatively expensive and/or difficult to manufacture medical circuit components. The subject patent provides an improved medical circuit component for managing rain-out. In particular the component may be an improved breathing tube, or insufflation system limb comprising a helically corrugated tube preferably incorporating a heater wire.
1. A component comprising:
a helically corrugated tube wherein the corrugation profile comprises alternating outer crests and inner troughs,
a heater wire associated with said outer crests,
wherein each said outer crest comprises a peak region, and the peak regions include local troughs comprising a small inward dip, and
said heater wire associated with said outer crests is located within said dip.
2. A component as claimed in claim 1 , wherein said tube has a substantially uniform wall thickness.
3. A component as claimed in claim 1 , wherein said tube has a maximum wall thickness not exceeding 3 times the minimum wall thickness.
4. A component as claimed in claim 1 , wherein said outer crests correspond to a location of maximum inner radius and maximum outer radius of said tube, and said inner troughs correspond to a location of minimum inner radius and minimum outer radius of said tube.
5. A component as claimed in claim 1 , wherein said tube includes an outer sheath supported on said outer crests.
6. A component as claimed in claim 5 , wherein said outer sheath traps air between adjacent outer crests.
7. A component as claimed in claim 5 , wherein said outer sheath restrains said heater wire associated with said outer crests in said local trough.
8. A component as claimed in claim 1 , wherein said helically corrugated tube includes multiple helix corrugations.
9. A component as claimed in claim 1 , wherein said component further comprises a heater wire associated with said inner troughs.
10. A component as claimed in claim 9 , wherein said heater wire associated with said inner troughs has a different heating density than said heater wire associated with said outer crests.
11. A component as claimed in claim 10 , wherein said heater wire associated with said inner troughs has a lower heating density than said heater wire associated with said outer crests.
12. A component as claimed in claim 1 , wherein said helically corrugated tube has a varying helix pitch.
13. A component as claimed in claim 12 , wherein said helically corrugated tube has a continuously variable helix pitch.
14. A component as claimed in claim 1 , wherein said component is one of:
a conduit for use in at least part of the exhaust arm of an insufflation system,
a breathing tube for use in a breathing circuit and
a catheter mount or tube for connection to a patient interface.
15. A medical circuit tube as claimed in claim 1 , wherein said tube is flexible as defined by passing the test for increase in flow resistance with bending according to ISO 5367.
16. A component as claimed in claim 1 , wherein said tube is an extruded corrugated tube.
17. A component as claimed in claim 1 , wherein said tube is a breathing tube and is terminated by a first connector at an inlet and a second connector at an outlet, and wherein only one gases passageway is provided the length between said inlet connector and said outlet connector.
18. A component as claimed in claim 1 , wherein at least at one end of said tube is a corrugation transition region wherein said helical corrugations transition to a substantially annular corrugation.
19. A component as claimed in claim 18 , wherein each end of said tube includes a corrugation transition region where said helical corrugations transition to a substantially annular corrugation.
20. A component as claimed in claim 1 , wherein an inner surface of the outer crest and an inner surface of the peak region are in contact with gases within the corrugated tube.
21. A method of forming a component comprising:
extruding a tube,
passing said extruded tube into a corrugator and forming corrugations in said extruded tube having a corrugation profile comprising alternating outer crests and inner troughs, and
wherein each said outer crest comprises a peak region, and the peak regions include local troughs comprising a small inward dip,
wherein said corrugations are helical, and
wherein said method further comprises a step of winding at least one heater wire into said local trough.
22. A method of forming a component as claimed in claim 21 , wherein said method further comprises applying an outer sheath over said component.
23. A method of forming a component as claimed in claim 22 , wherein said step of applying said sheath comprises extruding a sheath over said component.
24. A method of forming a component as claimed in claim 21 , wherein said extruded tube has a substantially uniform wall thickness at the time of corrugating.
25. A method of forming a component as claimed in claim 21 , wherein said outer crests correspond to a location of maximum inner radius and maximum outer radius of said component, and said inner troughs correspond to a location of minimum inner radius and minimum outer radius of said component.
26. A method of forming a component as claimed in claim 21 , wherein said helically corrugated component includes multiple helix corrugations.
27. A method of forming a component as claimed in claim 21 , wherein said method further comprises a step of winding at least one heater wire into said inner troughs.
28. A method of forming a component as claimed in claim 27 , wherein said heater wire associated with said inner troughs has a different heating density than said heater wire associated with said outer crests.
29. A method of forming a component as claimed in claim 28 , wherein said heater wire associated with said inner troughs has a lower heating density than said heater wire associated with said outer crests.
30. A method of forming a component as claimed in claim 21 , wherein said helically corrugated component has a varying helix pitch.
31. A method of forming a component as claimed in claim 30 , wherein said helically corrugated component has a continuously variable helix pitch.
32. A method of forming a component as claimed in claim 21 , wherein said tube is flexible as defined by passing the test for increase in flow resistance with bending according to ISO 5367.
33. A method of forming a component as claimed in claim 21 , wherein said method further comprises terminating a first end with a first connector, and terminating a second end with a second connector, and wherein only one gases passageway is formed between said first connector and said second connector.
34. A method of forming a component as claimed in claim 33 , wherein said step of forming said corrugations includes forming a transition region at each end of said component, and wherein said helical corrugations transition to a substantially annular corrugation in the vicinity of said first and second connector respectively.