US 12,220,894 B2
Multilayer composite tube with flame-resistant layers
Donald Bradley Campbell, Gallatin, TN (US); and Jordan Strunk, Portland, TN (US)
Assigned to Titeflex Corporation, Springfield, MA (US)
Filed by Titeflex Corporation, Springfield, MA (US)
Filed on Jan. 15, 2021, as Appl. No. 17/150,107.
Claims priority of provisional application 63/059,616, filed on Jul. 31, 2020.
Prior Publication US 2022/0032571 A1, Feb. 3, 2022
Int. Cl. B32B 1/08 (2006.01); B32B 7/12 (2006.01); B32B 15/20 (2006.01); B32B 27/20 (2006.01); B32B 27/32 (2006.01); F28F 1/00 (2006.01)
CPC B32B 1/08 (2013.01) [B32B 7/12 (2013.01); B32B 15/20 (2013.01); B32B 27/20 (2013.01); B32B 27/32 (2013.01); F28F 1/003 (2013.01); B32B 2250/03 (2013.01); B32B 2262/101 (2013.01); B32B 2264/1027 (2020.08); B32B 2264/301 (2020.08); B32B 2307/3065 (2013.01); B32B 2311/24 (2013.01); B32B 2323/04 (2013.01); B32B 2597/00 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A refrigeration system comprising:
a compressor;
an evaporator coil;
a composite refrigeration line set coupled between the compressor and the evaporator coil to form a fluid circuit between the compressor and the evaporator coil, the composite refrigeration line set comprising:
a suction line; and
a return line;
characterized in that one or more of the suction line and the return line are a composite refrigeration line set tube comprising:
an inner plastic tube;
a first adhesive layer external to the inner plastic tube;
an aluminum layer circumferentially surrounding the first adhesive layer and coupled to the inner plastic tube via the first adhesive layer;
a second adhesive layer external to the aluminum layer; and
an outer plastic layer circumferentially surrounding the aluminum layer and coupled to the aluminum layer via the second adhesive layer;
wherein:
the inner plastic tube is polyethylene of raised temperature;
the outer plastic layer is polyethylene of raised temperature; and
the outer plastic layer comprises at least one a flame-resistant compound combined with the polyethylene of raised temperature, wherein the at least one flame-resistant compound includes one or more selected from the group consisting of: glass fibers, nanoclay, nanofibers, a thermal foaming agent, and a combination thereof;
the aluminum layer has one or more properties selected from the group consisting of:
being an alloy having 0.1% or greater magnesium by mass; and
being an alloy selected from the group consisting of: AL 3004, AL 3005, AL 5052, AL 6061, and AL 8006; and
the composite refrigeration line set tube has a burst pressure in excess of 1950 pounds per square inch; and; and
wherein the composite refrigeration line set tube has a flame and smoke spread rating of no more than 25/50 when tested in isolation using Appendix A1.22 of the CAN/ULC-S102-10 Standard Test Method for Surface Burning Characteristics of Building Materials and Assemblies; and
a refrigerant received within the fluid circuit;
wherein the refrigerant is an A2L refrigerant defined as:
(i) exhibiting flame propagation when tested at 140° F. and 14.7 psia;
(ii) having a lower flammability limit (LFL) >0.0062 lb/ft3;
(iii) having a heat of combustion <8169 Btu/lb; and
(iv) having a maximum burning velocity ≤3.9 in/s when tested at 73.4° F. and 14.7 psia in dry air.