PEX pipe for high pressure and high temperature applications
A flexible tubing having a PEX inner core is surrounded by a reinforcing structure, such as a braid. The reinforced flexible tubing meets NFPA Standards for the Installation of Sprinler Systems (13/13R/13D) in both residential and commercial buildings. The reinforced flexible tubing is suitable for a variety of other high temperature/high pressure applications. The tube's flexible characteristics facilitate its installation at a greatly reduced cost, especially in retrofitting existing structures. An adhesive can be used to improve the overall strength and stability of the reinforcing structure surrounding the PEX core. Optionally, a protective outer layer can be applied over the reinforcing structure.
1. A flexible tubing for commercial and residential high pressure and high temperature applications, the flexible tubing comprising:
an innermost layer formed of cross-linked polyethylene (“PEX”), the innermost layer having a Standard Dimension Ratio (SDR) value of at least about 7.0, the cross-linked polyethylene comprising chemically formed cross-link bonds;
a reinforcing structure surrounding the innermost layer, the reinforcing structure being coupled to the innermost layer without being embedded in another material; and
an outer layer disposed about the reinforcing structure,
wherein the flexible tubing is radially expandable and has a bend radius of at least about 2.5 times an outside diameter.
2. The flexible tubing of claim 1 , wherein the flexible tubing has a short term burst rating of at least about 1,000 psi and a long term hydrostatic strength of at least about 175 psi at about 120° F.
3. The flexible tubing of claim 1 , further comprising:
a mechanical fitting fixedly attached to an end of the flexible tubing without the use of glue or solvent to make joints therebetween.
4. The flexible tubing of claim 1 , wherein the reinforcing structure is formed with the innermost layer.
5. The flexible tubing of claim 1 , wherein the reinforcing structure is at least one of a spiral, helical, woven/interwoven, or loop braid.
6. The flexible tubing of claim 1 , wherein the innermost layer has an SDR value between about 7.4 and about 14.0.
7. The flexible tubing of claim 1 , further comprising an adhesive disposed between the reinforcing structure and the innermost layer.
8. A flexible tubing, comprising:
an innermost layer comprising cross-linked polyethylene (“PEX”), the cross-linked polyethylene comprising chemical cross-linking;
a reinforcing structure surrounding the innermost layer, the reinforcing structure being coupled to the innermost layer without being embedded in another material; and
an outer layer disposed about the reinforcing structure,
wherein the flexible tubing is radially expandable and has a bend radius of at least about 2.5 times an outside diameter.
9. The flexible tubing of claim 8 , wherein the flexible tubing has a short term burst rating of at least about 1,000 psi and a long term hydrostatic strength of at least about 175 psi at about 120° F.
10. The flexible tubing of claim 8 , further comprising:
a mechanical fitting fixedly attached to an end of the flexible tubing without the use of glue or solvent to make joints therebetween.
11. The flexible tubing of claim 8 , wherein the reinforcing structure is formed with the innermost layer.
12. The flexible tubing of claim 8 , wherein the reinforcing structure is at least one of a spiral, helical, woven/interwoven, or loop braid.
13. The flexible tubing of claim 8 , further comprising an adhesive disposed between the reinforcing structure and the innermost layer.
14. The flexible tubing of claim 8 , wherein the flexible tubing meets the National Fire Protection Association's Standard 13 for pipe.
15. The flexible tubing of claim 14 , wherein the flexible tubing meets the National Fire Protection Association's Standard 13R for pipe.
16. A dry-pipe sprinkler system including the flexible tubing of claim 14 .
17. A flexible tubing for commercial and residential high pressure and high temperature applications, the flexible tubing comprising:
an innermost layer formed of cross-linked polyethylene (“PEX”), the innermost layer having a Standard Dimension Ratio (SDR) value of at least about 7.0 , the cross-linked polyethylene comprising chemical cross-linking;
means for reinforcing the innermost layer to provide the flexible tubing with a short term burst rating of at feast about 1000 psi and a long term hydrostatic strength of at least about 175 psi at about 120° F; and
an outer layer disposed about the reinforcing means,
wherein the flexible tubing is radially expandable and has a bend radius of at least about 2.5 times an outside diameter.
18. The flexible tubing of claim 1 , wherein the cross-link bonds are produced by a peroxide method or a silane method.
19. The flexible tubing of claim 3 , wherein the mechanical fitting is configured to couple with at least one of a plumbing system, a hydronic radiant heating system, and a high pressure and high temperature fire sprinkler system.
20. The flexible tubing of claim 8 , wherein the chemical cross-linking is created by a peroxide method or a silane method.
21. The flexible tubing of claim 10 , wherein the mechanical fitting is configured to couple with at least one of a plumbing system, a hydronic radiant heating system, and a high pressure and high temperature fire sprinkler system.
22. The flexible tubing of claim 17 , wherein the chemical cross-linking is created by a peroxide method or a silane method.
23. The flexible tubing of claim 1 , wherein the cross-linked polyethylene comprises at least about 85% cross-linking and carbon-carbon cross-link bonds.
24. The flexible tubing of claim 8 , wherein the cross-linked polyethylene comprises at least about 85% cross-linking and carbon-carbon cross-link bonds.
25. The flexible tubing of claim 17 , wherein the cross-linked polyethylene comprises at least about 85% cross-linking and carbon-carbon cross-link bonds.