Tubing for transporting air samples in an air monitoring system
View Patent ↗An air monitoring system includes a tubing having a metallic inner layer and an outer jacket to provide optimal transport of air samples.
1. A method of efficiently transporting an air sample containing particulate matter through tubing, comprising:
obtaining an air sample from a first location;
transporting the air sample to a second location in a tubing having a metallic inner layer and an outer jacket that includes a non-metallic material, wherein the inner layer substantially does not oxidize from exposure to ambient air conditions and wherein the combination of said inner layer and outer jacket has minimal absorption, desorption, and off-gassing with respect to the air sample to transport the air sample for accurate characteristic measurements; and
measuring at least one characteristic of the air sample with one or more sensors at the second location.
2. The method according to claim 1 , wherein the metallic inner layer includes stainless steel.
3. The method according to claim 2 , wherein the tubing has an effective flexure modulus that is between 50 and 100 times less than that of 304 stainless steel tubing of equivalent inner and outer diameters.
4. The method according to claim 1 , wherein the metallic layer is formed from a ribbon with an overlap region.
5. The method according to claim 4 , wherein the metallic inner layer includes a stainless steel ribbon that has been folded to form a tube over which a plastic jacket is extruded.
6. The method according to claim 5 , wherein the folded stainless steel ribbon has a thickness of between 0.0005 and 0.004 inches.
7. The method according to claim 6 , wherein the stainless steel ribbon in its unfolded state is about one inch wide.
8. The method according to claim 4 , wherein the tubing has an outer diameter of about ⅜ of an inch and an inner diameter ranging from about ¼ inch to about 5/16 of an inch.
9. The method according to claim 1 , wherein the metallic inner layer includes Gold.
10. The method according to claim 1 , wherein the metallic inner layer includes Bronze.
11. The method according to claim 1 , wherein the metallic inner layer includes Nickel.
12. The method according to claim 1 , wherein the metallic inner layer includes aluminum with a chromate coating.
13. The method according to claim 1 , wherein the jacket includes one or more of polyethylene and polyvinyl chloride.
14. The method according to claim 1 , wherein the tubing further includes an adhesive material to secure the metallic layer to the jacket.
15. The method according to claim 14 , wherein the adhesive material includes an ethylene copolymer.
16. The method according to claim 1 , wherein the metallic layer is formed from a ribbon with welded edges to form a seam.
17. The method of claim 1 , wherein the metallic layer is a metallized plastic with an overlap region.
18. The method of claim 17 , wherein the metal coated plastic is a thin polyester film with stainless steel deposited upon it.
19. The method according to claim 1 , further including securing at least one conductor to provide one or more of signal, power, and communication.
20. The method according to claim 19 , wherein the at least one conductor extends in a region between the tubing jacket and a cable jacket.
21. The method according to claim 1 , wherein the jacket is composed of a conductive plastic that establishes a conductive path between the metallic inner layer and an outer surface of the tube.
22. The method according to claim 1 , wherein a conductive drain wire is disposed along a length of the tube in contact with an outer surface of the tubing.
23. The method according to claim 22 , wherein the tube and drain wire are covered with a conductive shield.
24. The method according to claim 1 , further including providing a first conductive path for signaling, a second conductive path for communication, and a third conductive path for power.
25. The method according to claim 1 , wherein the metallic inner layer is applied as metallic paint.
26. The method according to claim 1 , wherein the metallic inner layer is formed by metal deposition directly to the jacket.
27. The method according to claim 1 , further including providing a conductive medium disposed along a length of the tubing to enable measurement of the length of the tubing.
28. The method according to claim 27 , wherein the conductive medium includes a pair of isolated wires having lengths that are coupled in proportion to the length of the tubing and which are electrically connected together at the point where the tubing is placed to draw an air sample.
29. The method according to claim 28 , wherein the length of the tubing is derived by measuring a resistance of the conductor pair to the point to which the tube is drawing an air sample.
30. The method according to claim 28 , wherein the length of the tube is derived via a time domain reflectometer connected to the conductor pair whose length is closely coupled in proportion to the length of the tube.
31. The method according to claim 1 , further including providing a heat source disposed along the length of the tubing.
32. The method according to claim 31 , wherein the heat source is a resistive wire with a current flowing through it.
33. The method according to claim 32 , wherein the resistive wire is composed of tungsten.
34. The method according to claim 1 , wherein the tubing has an effective flexure modulus that is between 50 and 100 times less than that of 304 stainless steel tubing.
35. The method according to claim 1 , wherein the inner layer has absorption, desorption, and off-gassing characteristics in combination with said outer jacket and with respect to the air sample at least as low as an inner layer of stainless steel having a thickness of at least 0.0002 inches.
36. The method according to claim 1 , wherein the inner layer is substantially inert for non-halogenated VOCs.
37. A method of transporting an air sample, comprising:
obtaining an air sample from a first location;
transporting the air sample to a second location in a tubing having a metallic inner layer and an outer jacket that includes a non-metallic material; and
measuring at least one characteristic of the air sample with one or more sensors at the second location,
wherein the jacket is composed of a conductive plastic that establishes a conductive path between the metallic inner layer and an outer surface of the tube,
wherein the conductive plastic is a plastic resin impregnated with carbon.
38. A method of efficiently transporting an air sample containing particulate matter through tubing, comprising:
obtaining an air sample from a first location;
transporting the air sample to a second location in a tubing that is composed of a non-metallic material and a metallic material, wherein the metallic material substantially does not oxidize from exposure to ambient air conditions and wherein the combination of non-metallic material and a metallic material has minimal absorption, desorption, and off-gassing with respect to the air sample; and
measuring at least one characteristic of the air sample with one or more sensors at the second location.
39. The method according to claim 38 , wherein the tubing material provides a conductive path to prevent electrostatic charge build up.
40. The method according to claim 38 , wherein the metallic material is stainless steel and the nonmetallic material is a fluoroplastic.
41. The method according to claim 38 , wherein the tubing has an effective flexure modulus that is between 50 and 100 times less than that of 304 stainless steel tubing.