Patent Application
20240133599
Multilayer composite pipes are designed and used to convey liquids, primarily water, for applications such as in floor heating, radiator heating, and water supply.
One aspect of the invention provides a composite refrigeration line set including: at least one selected from the group consisting of: a suction line and a return line. One or more of the suction line and the return line are a composite refrigeration line set tube including: an inner plastic tube; a first adhesive layer positioned about the inner plastic tube; an aluminum layer positioned about the first adhesive layer and coupled to the inner plastic tube via the first adhesive layer; a second adhesive layer positioned about the aluminum layer; and an outer plastic layer positioned about the aluminum layer coupled to the aluminum layer via the second adhesive layer. The inner plastic tube is polyethylene-fiberglass composite. The outer plastic tube is polyethylene-fiberglass composite. The aluminum layer includes an alloy selected from the group consisting of AL 3004-O, AL 3005-O, and AL 3555-O. The aluminum layer has a thickness range for a given pipe size as specified in Table 2.
This aspect of the invention can have a variety of embodiments. The aluminum layer can be butt-welded to itself. The composite refrigeration line set can further include a low-emissivity layer positioned about the outer plastic layer. The low-emissivity layer can include low-emissivity aluminum. The low-emissivity layer can include a metallized film.
The composite refrigeration line set tube can have a burst pressure in excess of 2100 pounds per square inch. The composite refrigeration line set can further include a reinforcement layer.
Another aspect of the invention provides a refrigeration system including: a compressor; an evaporator coil; the composite refrigeration line set as described herein coupled between the compressor and the evaporator coil to form a fluid circuit between the compressor and the evaporator coil; and a refrigerant received within the fluid circuit.
Another aspect of the invention provides a composite refrigeration line set including: at least one selected from the group consisting of: a suction line and a return line. One or more of the suction line and the return line are a composite refrigeration line set tube including: an inner plastic tube; a first adhesive layer positioned about the inner plastic tube; an aluminum layer positioned about the first adhesive layer and coupled to the inner plastic tube via the first adhesive layer; a second adhesive layer positioned about the aluminum layer; and an outer plastic layer positioned about the aluminum layer coupled to the aluminum layer via the second adhesive layer. The inner plastic tube is polyethylene of raised temperature. The outer plastic tube is polyethylene of raised temperature. The aluminum layer comprises AL 3555-O. The aluminum layer has a thickness range for a given pipe size as follows for the indicated pipe sizes:
This aspect of the invention can have a variety of embodiments. The aluminum layer can be butt-welded to itself. In one embodiment, the aluminum layer does not include a corrosion-inhibiting protective coating.
The composite refrigeration line set can further include a low-emissivity layer positioned about the outer plastic layer. The low-emissivity layer can include low-emissivity aluminum. The low-emissivity layer can include a metallized film.
The composite refrigeration line set tube can have a burst pressure in excess of 1950 pounds per square inch. The composite refrigeration line set can further include a reinforcement layer. In one embodiment, one or more of: the inner plastic tube is polyethylene-fiberglass composite and the outer plastic tube is polyethylene-fiberglass composite. In one embodiment, the inner plastic tube is polyethylene-fiberglass composite; and the outer plastic tube is polyethylene-fiberglass composite.
Another aspect of the invention provides a refrigeration system including: a compressor; an evaporator coil; the composite refrigeration line set as described herein coupled between the compressor and the evaporator coil to form a fluid circuit between the compressor and the evaporator coil; and a refrigerant received within the fluid circuit.
Another aspect of the invention provides a refrigeration system including: 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; and a refrigerant received within the fluid circuit. The composite refrigeration line set includes: a suction line; and a return line. One or more of the suction line and the return line are a composite refrigeration line set tube including: 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. The inner plastic tube is polyethylene of raised temperature. The outer plastic tube is polyethylene of raised temperature. The outer plastic tube includes: carbon black and a flame retardant. 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-S102.02-10 Standard Test Method for Surface Burning Characteristics of Building Materials and Assemblies. 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.
This aspect of the invention can have a variety of embodiments. The flame retardant can be magnesium hydroxide (Mg(OH)2). The outer plastic tube can include between about 35% and about 45% magnesium hydroxide (Mg(OH)2) by weight. The outer plastic tube can include between about 1.5% and about 2.5% carbon black by weight.
Another aspect of the invention provides a composite refrigeration line set including: a suction line; and a return line. One or more of the suction line and the return line are a composite refrigeration line set tube including: 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. The inner plastic tube is polyethylene of raised temperature. The outer plastic tube is polyethylene of raised temperature. The outer plastic tube includes: carbon black and a flame retardant. 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-S102.02-10 Standard Test Method for Surface Burning Characteristics of Building Materials and Assemblies.
For a fuller understanding of the nature and desired objects of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawing figures wherein like reference characters denote corresponding parts throughout the several views.
The instant invention is most clearly understood with reference to the following definitions:
As used herein, the singular form “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from context, all numerical values provided herein are modified by the term about.
As used herein, the term “alloy” refers to a homogenous mixture or metallic solid solution composed of two or more elements. Examples of alloys include austenitic nickel-chromium-based super-alloys (available, e.g., under the INCONEL® trademark from Huntington Alloys Corporation of Huntington, West Virginia), brass, bronze, steel, low carbon steel, phosphor bronze, stainless steel, and the like.
As used in the specification and claims, the terms “comprises,” “comprising,” “containing,” “having,” and the like can have the meaning ascribed to them in U.S. patent law and can mean “includes,” “including,” and the like.
As used in the specification and claims, the term “fiberglass” refers to fiber-reinforced plastic using glass fiber. Generally speaking, “E-glass” is understood to refer to alumina-calcium-borosilicate glasses used as a general purpose reinforcement where strength and high electrical resistivity are desired, while “S-glass” is understood to refer to magnesium aluminosilicate glasses used for textile substrates or reinforcement in composite structural applications that require high strength, modulus, and durability under conditions of extreme temperature or corrosive environments.
Unless specifically stated or obvious from context, the term “or,” as used herein, is understood to be inclusive.
As used herein, the term “metal” refers to any chemical element that is a good conductor of electricity and/or heat, and alloys thereof. Examples of metals include, but are not limited to, aluminum, cadmium, niobium (also known as “columbium”), copper, gold, iron, nickel, platinum, silver, tantalum, tin, titanium, zinc, zirconium, and the like.
As used herein, the term “resin” refers to any synthetic or naturally occurring polymer. Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 (as well as fractions thereof unless the context clearly dictates otherwise).
Multilayer composite pipes can be fabricated from multiple layers of material including various plastics, adhesives and, in some cases metal layers. Exemplary constructions are summarized below.
Referring to
Plastic layers 102, 110 can be selected from a variety of materials such as polyethylene fiberglass composite (or “glass-filled polyethylene plastic”), thermoplastics, thermoplastic elastomers, polyethylene, polyethylene, polypropylene, polyvinyl chloride (PVC), polyamide, fluoropolymers, polyvinylidene fluoride (PVDF), fluorinated ethylene propylene (FEP), perfluroalkoxy alkane (PFA), and the like.
The metal layer(s) can be aluminum or aluminum alloys such as aluminum-manganese alloy. Exemplary aluminum alloys include the 1000 series (e.g., 1050, 1070, and the like), 3000 series (e.g., 3003, 3004, 3005, 3555, 3103, 3105, etc.), 5000 series (e.g., 5052) 6000 series (e.g., 6060, 6061, and the like), and 8000 series (e.g., 8006, 8011, and the like). A variety of tempers can be utilized including —O (full soft (annealed)).
In some embodiments, a corrosion-inhibiting protective coating can be applied to alloys having high magnesium content (0.8% and greater such as in AL 5052-O and AL 3004-O) to prevent blooming or oxidation of the magnesium on the surface of the aluminum alloy.
A variety of suitable thicknesses for alloys are provided below to achieve a burst pressure in excess of 2,100 psi (or at least 1950 psi) at ambient temperature. As can be seen, a multitude of thickness ranges for the reinforcement material, pipe thickness, and reinforcement material composition can be used in the pipe construction, while still allowing for burst pressure thresholds to be in excess of the 1950 psi requirement for some piping use fields (e.g., Underwriters Laboratories Inc. Standard for Safety for Refrigerant Containing Components and Accessories, Nonelectrical (UL 207)). (“Pipe size” is a nominal size to replicate the inner diameter of ACR soft copper tubing for the equivalent ACR soft copper outer diameter. The relationship between the outer diameter and inner diameter for ACR soft copper is provided as Table 3.)
For common water conveyance applications, standard multilayer composite pipes are sufficient and work well given their flexibility and light-weight nature. Also, given the previously mentioned benefits of the product, there are many other applications where this type of pipe may be used. These other applications could include the conveyance of other types of liquids and gases such as refrigerants, natural gas, propane, and process and medical gases such as argon, helium, nitrogen, and the like. Depending on the application of the use for the multilayer composite pipe, greater performance standards may be required making it necessary to further enhance the standard multilayer product design to ensure higher pressure and temperature limits. This enhancement can be accomplished by adding yet another layer of material to the overall construction, thereby creating a reinforcement layer. Additionally or alternatively, the reinforcement can be added within the one of the layers described above.
The reinforcement can be constructed in several forms. For example, the reinforcement can be spirally (e.g., helically) wrapped, longitudinal, braided, and the like under, over, or within any of the layers. For example, a reinforcement layer can be around or within the inner layer of plastic 102, around or within the outer layer of plastic 110, around the gas (e.g., oxygen) barrier (e.g., metal) layer 106, or around or within the adhesive layers 104, 108. The reinforcement layer can completely cover or partially cover the surface of a pipe layer 102, 104, 106, 108, 110.
The reinforcement material can include one or more individual material spirals wrapped around the pipe (e.g., one material spirally wound with axial pitch of 0.25″ or four spirals with individual pitch of 1″ or 0.25″ collectively). Pipe capacity (e.g., in terms of burst strength) can be adjusted based on pitch, material selection, and the like. For example, the tubing can have a burst pressure in excess of 2,100 psi at 70° F. and 1,500 psi at 200° F.
The reinforcement can include one or more materials such as metal foils (e.g., aluminum or copper), plastic films, metal wire, plastic wire, fiberglass cords or fabric (e.g., AR-glass, C-glass, D-glass, E-glass, E-CR-glass, R-glass, S-glass, and the like), any type of filament material, aramids, para-aramids, poly-aramid synthetic fibers, aromatic polyester strands, and the like.
Exemplary fiberglass-high-density-polyethylene (PEHD) polymers are available under the CELSTRAN® trademark from CAN Holdings of Irving, Texas. The reinforcing materials can be coated (e.g., with a binder or primer), machined (e.g., roughened), etched, or otherwise treated to bond to or be embedded within the adhesive layers. In some embodiments, a particular adhesive layer (e.g., a tie resin, a solvent-based adhesive, a hot-melt adhesive, a high-temperature adhesive, and the like) is utilized to bond particular reinforcements. Exemplary high-temperature adhesives include grafted polyolefin adhesives such those grafted with reactive maleic anhydride and available under the OREVAC™ trademark from SK Functional Polymer of Courbevoie, France.
In some embodiments, the reinforcement is applied after the product is extruded (e.g., a spiral wrap applied with a wrapping machine). In other embodiments, a spiral wrap is formed with a rotating extrusion crosshead such that the spiral material is extruded within a layer of polymer or adhesive (e.g., wire inside polymer). In still another embodiment, a spiral wrap is formed with a rotating extrusion crosshead (e.g., polyester cord extruded in a helix around an underlying tube). In still another embodiment, a longitudinal wrap can be added to any layer of the pipe.
Referring to
Although a carbon-black-containing polymer outer layer 110 may meet a flame-spread rating of no more than 25 when tested in isolation (e.g., a pair consisting of a suction line and a return line as would be used in the field) using the ASTM E84-20 Standard Test Method for Surface Burning Characteristics of Building Materials and/or Appendix A1.22 of the CAN/ULC-S102.02-10 Standard Test Method for Surface Burning Characteristics of Building Materials and Assemblies, the carbon black generates smoke when exposed to flame that may preclude use in the plenum of a building. This could be addressed with smoke-suppressant additives; however, such additives cause dripping of flaming polymer, which is undesirable.
Accordingly, outer layer 110 can further include flame retardant to prevent or resist smoke production.
The outer layer 110 can include flame resistant material within the layer's composition. For example, the outer layer 110 can include flame retardants (e.g., magnesium hydroxide (Mg(OH)2), aluminum trihydrate, and/or halogenated fire retardants), glass fibers, nanoclays, nanofibers, and the like. Further, the flame protective layer 110 can also include a plastic component, similar to the plastic layer 102 discussed above. For example, the plastic component can include one or a combination of thermoplastics, thermoplastic elastomers, polyethylene, polyethylene, polyethylene of raised temperature (PERT), polypropylene, PVC, polyamide, fluoropolymers, PVDF, FEP, PFA, and the like. For example, the outer layer 110 can be solution or suspension in which a polymer is the dispersion medium and the flame retardant is dissolved or dispersed within the polymer or adhered to the polymer.
The filler loading for the flame-protective material can be 35-45% by weight of the outer layer 110. In some cases, the specific gravity for the outer jacket can be greater or equal to 1, 1.1, 1.2, and the like (e.g., 1.279). In some cases, thermal foaming agents can also be a component of the layer 110, which can increase the char volume of the layer 110 when exposed to flame.
The polymer, carbon black, and flame retardant can be combined in homogenous pellet form before extrusion. Also, because certain flame retardants such as Mg(OH) 2 are hygroscopic, it may be advantageous to dry the composite pellets prior to loading into the extrusion hopper.
Referring now to
Exemplary embodiments are described below from innermost layer to outermost layer in descending order.
Although embodiments having two metal layers 206a, 206b are described above, three or more metal layers could be utilized in accordance with the invention.
The metal layers 206a, 206b can be the same or different with regard to one or more of material, thickness, or other properties. For example, either the inner metal layer 206a or outer metal layer 206b can be thicker than the other layer 206b, 206a. Each metal layer 206a, 206b can be bonded to itself, e.g., through welding (e.g., overlap or butt) with methods such as ultrasonic, laser, tungsten inert gas, and the like).
Adhesive 205 can have a sufficient compressive strength to prevent elongation of metal layers 206a, 206b. Without being bound by theory, Applicant believes that most hot-melt adhesives would have sufficient compressive strength properties.
Without being bound by theory, Applicant believes that a multilayer composite pipe having multiple metal layers 206a, 206b having thicknesses a and b, respectively, will have superior properties (e.g., burst strength, bend radius, bending force, kink resistance) than a multilayer composite pipe having a single metal layer 106 of the same material of thickness c=a+b. For example, the metal layers 206a, 206b may slide past each other during bends.
Multiple metal layers 206a, 206b also avoid single-point failures. Single-point failures in the metal layer can occur for a variety of reasons, but some of the most common are poor weld integrity, reduction of strip thickness, and strip inclusions.
Current constructions of multilayer pipes utilize single aluminum layers that are axially welded with methods such as ultrasonic, laser, and tungsten inert gas, etc. These welding methods can suffer from quality issues that result in reduced strength of the aluminum layer at the weld or heat-affected zone. The locations of these affected areas are small, 0.001″ (0.0254 mm) to 0.25″ (6.35 mm) in length and, in the case of ultrasonic welding, hidden from view, making conventional quality monitoring difficult. With a single layer of welded metal, the overall burst strength of the tubing can be significantly reduced because of reduced weld quality. The addition of another layer of metal can provide necessary backing to prevent reduction in strength for single point failures. While the simplest construction places both weld seams in the same radial location, further strength improvements are realized when the weld seams are located at opposite radial locations.
Similarly, single-layer metal can suffer decreased performance as a result of reduced strip thickness. The metal strip used to fabricate multilayer pipe can have the thickness inadvertently reduced several ways, with some occurring during the production of the strip and some during the production of the multilayer pipe. Foreign-matter-induced thinness is particularly difficult to identify and prevent. The strip is produced by progressively rolling metal stock down to a suitable thickness. During this process, foreign matter that lands on the stock can be rolled into the stock, creating a reduced thickness in a relatively small area. This can present as a single point failure in a multilayer pipe and can be prevented by the addition of a second layer of welded metal.
The metal strip can also have inclusions (foreign material) in the base material that are not homogenous or compatible with the alloy. After the rolling process, these inclusions can cause a reduction in strength and may present as a single point failure in a single layer of metal. This can be prevented by the addition of a second layer of welded metal.
Pipe Assembly with Reflective Insulation
In another aspect of the invention, a pipe assembly can include an inner component, an outer component, and a reflective insulation system arranged between the two components.
The inner component, hereinafter called the inner pipe, can be a pipe of a diameter and structure/composition designed to transport a fluid there through, e.g., a refrigerant or other fluid needing insulation.
The outer component, hereinafter called the outer pipe, can also be a pipe having a diameter larger than the inner pipe, the diameter difference creating a gap that is part of a reflective insulation system between the inner pipe and the outer pipe that provides insulation value to the pipe assembly.
One example of a reflective insulation system can be to include a reflective material as part of the outer surface of the inner pipe and/or the inner surface of the outer pipe. In some embodiments, the outer pipe consists essentially or solely of a reflective material. This reflective material can be any kind of material having low emissivity (“low-e”) (e.g., having an emissivity value of 0.05 or less) to function in the reflective insulation system and can be made part of the outer surface of the inner pipe in any way. For example, a film of low-e material can be adhered to the outer surface of the line set pipe using an adhesive. The reflective layer can be roll-formed and welded or extruded over the inner most layer of the inner pipe. An example of such an adhered material can be a layer of aluminum, which can be adhered to the outer surface of the line set pipe using an adhesive, for example. For example, the low-e layer can be uncovered metal layer 206b in Embodiment C and provide both mechanical strength and low emissivity. The added outer layer of aluminum can provide a reflective low-e surface as part of the reflective insulation system. In some embodiments, the outer metal layer can be polished, either prior to or after formation of the inner pipe.
The other part of the reflective insulation system is a gap that is created by the diameter difference between the inner and outer pipe, the gap being of sufficient size to provide a meaningful R-value to the pipe assembly, e.g., at least that provided by foam insulation of the prior art. An example of such an R-value obtained by practicing the invention is approximately an R-3.
Spacer structures can ensure that the gap between the inner pipe and outer pipe is maintained, so that the thermal effect of the reflective insulation system along the length of the pipe assembly is not compromised by a reduction in the gap size. The spacer structure to maintain the gap can be achieved by a number of different techniques, including using components in addition to the inner and outer pipe or using a part of the outer pipe as a spacer structure.
A first kind of spacer structure may be a mechanical kind, wherein spacers are positioned between the outer surface of the inner pipe and the inner surface of the outer pipe. The spacers can also be spaced apart from each other and positioned along the length of the inner pipe so that the gap is maintained over the run or length of the pipe assembly. This embodiment is depicted in
The outer pipe is designated by the reference numeral 35. The gap between the inner pipe and outer pipe is designated by the reference numeral 37 and is created as a result of the diameter difference of the inner pipe 31 and outer pipe 35.
Also shown is a clip 39 as an exemplary spacer structure. In
The spacing between adjacent clips along the run of the pipe assembly can be such that the desired gap is maintained along the length of the run. Too large of a spacing between clips may cause the outer pipe to sag and narrow the gap, thereby affecting the thermal performance of the reflective insulation system. Small spacings are also unnecessary as they can complicate the assembly process, increase cost by increasing the number of spacers, etc. An exemplary spacing is believed to be about 12 inches (about 30 cm) but other spacings, e.g., between 1 foot (about 30 cm) spacing for bends and 6 foot spacing (about 180 cm) for straight runs, can be used as well.
While the gap 37 can be any practical dimension, it is preferred that the gap size range between ¼″ (0.636 cm) and 1½ ″ (about 3.8 cm), more preferably range between ½″ (about 1.2 cm) and 1¼ ″ (3.175 cm), and most preferably be about 1 inch (2.54 cm). Too small of a gap can result in a low R-value for the reflective insulation system. Too large of a gap can increase the overall diameter of the pipe assembly and can cause problems in the installation as a result of this size increase. Too large of a gap can also increase the size of the outer pipe, which increases costs.
Instead of a clip or another mechanical device as a spacer structure, a part of the outer pipe can be employed as a spacer structure. Referring now to
A third spacer structure can also involve components of the outer pipe itself. In this embodiment, the outer pipe includes drawn-down sections along the length thereof. In this embodiment, and with reference to
The drawn-down section 73 functions as a spacer structure and is formed so that drawn down sections are spaced along the length of the outer pipe. The drawn down section 73 can maintain the gap 77 formed by the diameter difference between the inner pipe 74 and the outer pipe 71. While the spacing between adjacent drawn down sections 73 can vary, an exemplary range of a spacing is 1 to 6 feet, with a more preferred spacing of about 12 inches. The drawn-down sections can be made so that the inner surface 75 can contact the outer surface 76 of the inner pipe 74.
While two drawn-down sections are illustrated, more than two drawn-down sections can be implemented, e.g., in spacings like that shown in
The inner pipe can be composed of a variety of non-metallic, metallic materials, or combinations thereof, e.g., as described herein. The non-metallic materials preferably include one of thermoplastics and thermoplastic elastomers, and more preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like. The low-e outer surface can occupy the outer surface of the inner pipe and can be composed of roll-formed aluminum, extruded aluminum, or some other low-e surface-containing material, e.g., a metallized film that is readily available on the market, that is part of the inner pipe 31. The low-e outer surface of the inner pipe can be a material separate from the inner pipe, e.g., a film that is bonded to the inner pipe or aluminum that is roll-formed and compressed to the inner pipe or directly extruding over the inner pipe. In this embodiment, the inner pipe 31 can constitute at least two layers, with the presence of the low-e material of one layer creating the low-e outer surface of the inner pipe. The low-e outer surface functions as part of the reflective insulation system with the gap formed between the plastic outer pipe and the inner line set pipe, where the spacer structures can maintain the gap along the length of the pipe assembly.
The inner pipe 31 can also be composed of an aluminum pipe or other metal pipe where the outer surface thereof functions as the low-e surface.
The outer pipe 35 can also be composed of any material that permits the creation of the gap around the inner pipe. Examples include one of thermoplastics and thermoplastic elastomers, and preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like. These polymeric materials can provide a solid and durable plastic outer pipe. However, the plastic outer pipe can also be made of laminated plastic films, e.g., PET or similar materials, and can be sized to slide over the inner pipe, creating an air gap.
When using the clip 39 as a spacer, the clip can be composed of any material, including metallic and non-metallic materials or combinations thereof, that can provide sufficient support to create and maintain the gap of the reflective insulation system. Exemplary materials include molded thermoplastics and thermoplastic elastomers, preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like. The clip 39 can also be composed of a metallic material that can be stamped or cut to shape. The clip spacer can also be made of a foam material.
The same kind of materials described above for the
For the outer pipe of the embodiments of
While the reflective insulation system can include a low-e surface as the outer surface of the inner pipe, the low-e surface can also be located on the inner surface of the outer pipe 5. For example, the outer pipe 35 can include a low-e layer (e.g., aluminum or metallized film) bonded to the inner surface of the outer pipe 35. The techniques and types of material discussed above for providing the low-e surface as part of the inner pipe 31 can also be employed for the inner surface of the outer pipe 35.
Yet another embodiment of the invention can include a reflective insulation system with conventional line set piping. In this embodiment, both the suction or return line and the liquid line are employed along with a spacer and an outer thermal insulation sleeve. Referring to
As shown in
For the construction of the lines 81 and 83, a variety of materials and constructions can be used.
One multilayer pipe construction has an outer layer that is made of one of thermoplastics and thermoplastic elastomers, preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like. The outer layer is bonded to an aluminum or stainless steel layer that is bonded to an inner layer that is made of one of thermoplastics and thermoplastic elastomers, preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like.
Another multilayer pipe construction has an outer aluminum or other low-e surface (low e optional) that is bonded to an inner layer that is made of one of thermoplastics and thermoplastic elastomers, preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like.
Other possible materials and constructions for the lines 81 and 83 include: solid aluminum pipe or some other solid metal with a low-e surface, although the low-e surface is optional on the lines 81 and 83, especially if the low-e surface is used as part of the outer sleeve 89; solid metal pipe (copper, stainless steel, etc.); and solid plastic pipe that is made of one of thermoplastics and thermoplastic elastomers, preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like.
As depicted in
While the embodiments of
While the outer thermal insulation sleeve 99 is shown with one type of construction, e.g., plastic laminated film (PET or other similar material) with an inner low-e surface, other constructions can be employed. These constructions can include a multilayer pipe construction with an outer layer that is made of one of thermoplastics and thermoplastic elastomers, preferably polyethylene, cross-linked polyethylene, polyethylene of raised temperature, polypropylene, polyvinyl chloride, polyamide, fluoropolymers, polyvinylidene fluoride, fluorinated ethylene propylene, perfluroalkoxy alkane, and the like bonded to an inner aluminum or other low e surface. The outer thermal insulation sleeve can also be solid aluminum pipe or some other solid metal material having a low-e surface.
While the spacer 94 is shown as surrounding the lines 92 and 95, it can have a different shape so long as the spacer sufficiently engages the lines 92 and 95 to hold them in a spaced apart relationship with each other and the inner surface of the outer thermal insulation sleeve 99 so as to create the space for the reflective insulation system. The spacer configuration shown in
A preferred construction of the pipe assembly of the embodiments of
The inventive pipe construction has a number of advantages over the prior art pipe construction used for line sets and the like. Unlike the typical line set construction that uses a foam insulation, the hard outer pipe better protects the pipe assembly from damage during the installation process. The hard outer pipe is also less likely to be compressed and a reduction in thermal properties is avoided, unlike the prior art line set wherein the foam insulation can be compressed and/or damaged and thermal properties can be compromised. The outer pipe can stand up to the outside elements and will not deteriorate, which is not the case for typical line set foam insulation.
Manufacturing advantages are also obtained with the inventive pipe construction as the outer pipe can be produced and installed over the inner pipe in the same production stream allowing for faster production times. In contrast, when using the prior art foam insulation, the foam is separately manufactured and then later combined with a line set pipe, which is a much slower product making operation.
The foam insulation used in prior art pipes is normally extruded and this kind of extrusion equipment is very costly compared to a simple plastic pipe extrusion line. Also, the foam insulation extrusion equipment takes up greater floor space than that of a plastic pipe extrusion line and the extrusion process for making the foam insulation is very slow compared to that of a plastic pipe.
The inner and outer pipes, when cylindrical in shape, can be made in any known ways. When making the outer pipe having the fins or drawn down sections, the pipes can be extruded or the like. The spacers can be molded if made from plastic or cut or stamped if made from metal.
When making the clip-using embodiment, generally, the clip can be attached to the inner pipe and then the outer pipe can be positioned over the spacer-containing inner pipe. The fin-containing outer pipe can be extruded directly over the inner pipe. Similarly, the pipe having the drawn-down sections can be extruded over the inner pipe and as part of the extruding process, the drawn-down sections can be formed. In the alternative, the outer pipe can be positioned over the inner pipe and the drawn-down sections formed thereafter.
The inventive pipe assemblies can be used in any application that typical line set piping is used. For example, the single pipe assembly of
In fact, any application where a pipe with a flowing fluid there through or a set of pipes with flowing fluid are in need of insulation exists, the pipe assembly of the invention can be implemented, either where the pipe assembly uses a single pipe for fluid flow such as that disclosed in
The flame protective composite tubes described above can be used for a variety of applications. For example, the flame protective composite tubes can be used for common water conveyance applications. However, there are many other applications for which this type of tube can be used. These other applications could include the conveyance of other types of liquids and gases such as refrigerants, natural gas, propane, and process and medical gases such as argon, helium, nitrogen, and the like.
The refrigeration system can include a suction line and a return line. Either or both of the suction line and the return line can include the flame protective composite tubes described above.
In one embodiment, multilayer composite tubes can be utilized as line sets for a refrigeration or air conditioning system carrying a flammable (e.g., slightly flammable or highly flammable) refrigerant.
Refrigerants are listed by the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) in ASHRAE Standard 34 (2019). The ASHRAE 34 Standard Committee determines toxicity and flammability classification. Class A refrigerants have lower toxicity. Class B refrigerants have higher toxicity. Flammability classifications are summarized in Table 6-1 of ASHRAE Standard 34. Embodiments of the invention can be utilized with A1, A2L, A2, A3, B1, B2L, B2, or B3 refrigerants.
A Class 2L refrigerant is understood according to ASHRAE Standard 34 (2019); specifically, under § 6.1.3.2 of ASHRAE Standard 34 (2019) a Class 2L refrigerant meets all four of the following conditions: (1) exhibits flame propagation when tested at 140° F. (60° C.) and 14.7 psia (101.3 kPa); (2) has an LFL >0.0062 lb/ft3 (0.10 kg/m 3); (3) has a heat of combustion <8169 Btu/lb (19,000 kJ/kg); (4) has a maximum burning velocity of ≤3.9 in/s (10 cm/s) when tested at 73.4° F. (23.0° C.) and 14.7 psia (101.3 kPa) in dry air. A Class A refrigerant is understood according to ASHRAE Standard 34 § 6.1.2 (2019) as having an OEL (occupational exposure limit) of 400 ppm or greater.
Many of such refrigerants have a low global warming potential (GWP), e.g., a GWP of 500 or lower.
Exemplary refrigerants are listed in Table 5 below.
Accordingly, embodiments of the invention can include both a system including one or more AC/refrigeration components (e.g., a compressor and/or an evaporator coil), a multilayer-composite-tube line set, and refrigerant (e.g., in the assembled system or in a container for charging the system after assembly) as well as a system including a multilayer-composite-tube line set and a container of refrigerant for charging an AC/refrigeration system after installation of the multilayer-composite-tube line set between the evaporator coil and the compressor.
The composite multi-layer tube can be configured to meet one or more applicable standards. For example, the composite multi-layer tube can be configured to have a flame and smoke spread rating of no more than 25/50 when tested in isolation (e.g., a pair consisting of a suction line and a return line as would be used in the field) using the ASTM E84-20 Standard Test Method for Surface Burning Characteristics of Building Materials and/or Appendix A1.22 of the CAN/ULC-S102-10 Standard Test Method for Surface Burning Characteristics of Building Materials and Assemblies. The composite multi-layer tube can be configured such that the aluminum layer remains intact after completion of one of these tests.
Although preferred embodiments of the invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.
The entire contents of all patents, published patent applications, and other references cited herein are hereby expressly incorporated herein in their entireties by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2304578.4 | Mar 2023 | GB | national |
This application is a continuation under 35 U.S.C. § 120 of PCT International Application No. PCT/US23/77432, filed Oct. 20, 2023, which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 63/380,628, filed Oct. 24, 2022, and U.K. Patent Application No. 2304578.4, filed Mar. 29, 2023. The entire content of each of these applications is hereby incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 63380628 | Oct 2022 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2023/077432 | Oct 2023 | US |
| Child | 18500669 | US |
