Multilayer HOSE assembly with integrated thermal insulation and method of manufacture

Abstract

A hose assembly creates a flexible hose that mitigates heat transmitted from the core of the hose to the hose surface while avoiding thermal insulation delamination. The hose comprises a series of concentric layers, wherein the first layer is a tubular thermoset layer that transmits fluid through the hose. A reinforcement braided layer surrounds the first thermoset layer to strengthen the first thermoset layer. An optional second thermoset layer or a thermoplastic layer may surround the reinforcement layer. A polymer foam thermal insulation layer integrally surrounds the hose's layers and is inseparably bonded to adjacent layers to prevent delamination. This multi-layer design provides the exemplary benefit of being cost-effective and more efficient to manufacture, and requires no adhesives or ties to hold the thermal insulation layer in place.

Description

[0001] MULTILAYER HOSE ASSEMBLY WITH INTEGRATED THERMAL INSULATION AND METHOD OF MANUFACTURE

[0002] Field of Invention

[0003] The present application relates to a high temperature multilayer hose assembly, and more particularly to a high temperature multilayer hose assembly with integrated thermal insulation suitable for thermal management and cooling applications or other medium to high heat applications.

[0004] Background

[0005] In industrial hoses, for example with hydraulic hoses applications where temperature control is necessary, such as injection-molding machines, vehicle cooling line, and battery coolers, hoses are required that can operate safely in a medium to high temperature (50°C up to 160°C) environment. Currently, conventional hoses comprising core tube made of high-temperature materials such as fluorpolymers (PTFE, PFA, MFA, FEP etc.) are used to manage these medium to high temperature applications. However, conventional temperature-resistant hoses are expensive and require additional safeguards for thermal management such as external thermal insulation to protect the operator from burns.

[0006] For example, conventional thermal hose solutions incorporate a conventional PTFE hose which is covered by a slitted or unslitted pipe thermal insulation foam layer that is slipped or wrapped over the hose assembly. The pipe thermal insulation is then held in place with adhesives or mechanical ties. Because pipe thermal insulation layers are difficult to slide over and secure in place along the length of a hose assembly, conventional hoses are costly and time intensive to create. Furthermore, because the thermal insulation is not an integral part of the hose assembly, conventional hose assemblies allow a small degree movement between the thermal insulation sleeve and the hose. This small degree of movement eventually fatigues the adhesive or mechanical tie holding the thermal insulation in place, causing early hose failure. As a result, conventional hoses often induce time-consuming maintenance or require expensive replacement parts.

[0007] Additionally, conventional hose designs decrease in hose length when pressurized internally, and therefore shrink back from hose fittings. This hose shrinkage decreases fitting retention during hose operation, making clamps or crimping at the fitting location necessary for conventional hoses assemblies. These clamps and crimps are a common failure point for hydraulic assemblies, and in turn further increase hose maintenance costs.

[0008] Summary of Invention

[0009] Accordingly, there is a need in the art for an improved and more durable insulated hose and assemblies that insulate the hose while avoiding the use of fallible and expensive materials of construction, adhesive or mechanical ties. In an exemplary embodiment, the hose design of the current application bonds thermal insulation integrally into a hose without the use of adhesives, mechanical ties, chemical surface treatments or physical surface treatments. This results in a hose design that is both more durable and more efficient to manufacture.

[0010] Because the thermal insulation is integral with the hose design, the design of the current application can be easily modified to change the thickness of a hose’s layers to better define the outside surface temperature of the hose and to avoid user burn injuries. The integrated thermal insulation also improves energy efficiency by preserving thermal energy by reducing radiant-heat loss.

[0011] Furthermore, there is a need for a hose design assembly that avoids the use of clamps or crimps in fitting attachments. The multi-layer nature of the hose design of the present application uses a durable reinforcement braid layer to enable the use of pushin fittings at both high and low hose temperatures. The braid allows the hose to increase in length while decreasing in inner and outer diameters when the hose is pressurized. This change in hose shape allows the hose to better retain push-in fittings compared to conventional hose designs, thereby avoiding the use of crimp or clamp fittings.

[0012] In an exemplary embodiment of the design of the current application, the multilayer hose assembly may include a hose wherein the hose is a multilayer construction comprising: a first thermoset layer; at least one reinforcement layer surrounding the first thermoset layer; and a polymer foam thermal insulation layer surrounding the at least one reinforcement layer; wherein the foam thermal insulation layer is inseparably bonded directly to adjacent layers with absence of mechanical ties or adhesives or tie layers.

[0013] In an exemplary embodiment, the multiplayer hose assembly may be made from a thermoset elastomer formulation comprising EPM polymer to withstand continuous operating temperature up to 160°C.

[0014] In an exemplary embodiment, the multiplayer hose assembly may further comprise a thermoset layer made from a thermoset elastomer formulation comprising a combination of EPM and EPDM polymers to withstand continuous operating temperature equal to or less than 160°C.

[0015] In an exemplary embodiment, the multiplayer hose assembly may be The multilayer hose assembly of any of claims 1-3, wherein the at least one reinforcement layer comprises a braid made from polyaramid yarn comprising polyaramid fibers or filaments, such that the yarn has a tensile strength in the range of 100-300 Newton.

[0016] In an exemplary embodiment, the multiplayer hose assembly may include at least one reinforcement layer comprising a braid made from polyaramid yarn comprising polyaramid fibers or filaments, such that the braid has an angle between 50-60 degrees normal to the hose length, and provides surface coverage of the thermoset layer between 35-55 percent.

[0017] In an exemplary embodiment, the multilayer hose assembly may further include at least one reinforcement layer which has a first reinforcement section that contacts a second reinforcement section, wherein both the first and second reinforcement sections are spirally wound at an angle between 50-60 degrees normal to the hose length, and the first reinforcement section is wound in an opposite direction relative to the second reinforcement section.

[0018] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation which comprises voids dispersed within a thermoplastic elastomer, and wherein the thermoplastic elastomer is a thermoplastic polyurethane formed with the reaction of aromatic isocyanate, aliphatic polyol and chain extender.

[0019] In an exemplary embodiment, the multilayer hose assembly may further include a thermoplastic polyurethane which is a linear polymer, and wherein: the isocyanate has a functionality of 2, the chain extender has a functionality of 2, and the polyol is a polyether-polyol with molecular weight between 3000-6000 gm / mol.

[0020] In an exemplary embodiment, the multilayer hose assembly may further include a thermoplastic polyurethane which is a linear polymer, and wherein: the isocyanate has a functionality of 2, the chain extender has a functionality of 2, and the polyol is a polyester-polyol with molecular weight between 500-12000 gm / mol.

[0021] In an exemplary embodiment, the multilayer hose assembly may further include a thermoplastic polyurethane which is a cross-linked polymer, and wherein: the isocyanate has a functionality higher than 2, or the chain extender has a functionality higher than 2.

[0022] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation comprising a closed cell structure.

[0023] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation comprising a semi-closed cell structure such that less 30% of voids or cells are interconnected.

[0024] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation comprising cells or voids with a diameter in the range of 20-200 microns.

[0025] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation with a density of 0.20-0.55 g / cm3.

[0026] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation with a thermal conductivity of 0.015-0.050 W / m / K.

[0027] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation which exhibits: a density reduction of 50-80% compared to the unfoamed polymer used for creating the foam thermal insulation, and a thermal conductivity reduction of 60-90% compared to the unfoamed polymer used for creating the foam thermal insulation.

[0028] In an exemplary embodiment, the multilayer hose assembly may further include In an exemplary embodiment, the multilayer hose assembly may further include foam thermal insulation which exhibits a flexural modulus between 5-20 MPa.

[0029] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation which exhibits a mass loss of 0.01 grams when subjected to 3000 abrasion cycles per ISO 6945:1991 with a vertical force of 25 Newton.

[0030] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation which exhibits a tear resistance between 50-200 kN / m.

[0031] In an exemplary embodiment, the multilayer hose assembly may further compris a second thermoset layer which surrounds the reinforcement layer and lies between the reinforcement layer and the foam thermal insulation layer.

[0032] In an exemplary embodiment, the multilayer hose assembly may further include a second thermoset layer which is chemically identical to the first thermoset layer.

[0033] In an exemplary embodiment, the multilayer hose assembly may further include a thermoplastic layer which surrounds the reinforcement layer and lies between the reinforcement layer and the foam thermal insulation layer.

[0034] In an exemplary embodiment, the multilayer hose assembly may further include a thermoplastic layer which is chemically identical to the foam thermal insulation layer.

[0035] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation layer which is bonded to the lower layer with a minimum bond strength of 1 .5 N / mm.

[0036] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation layer which is inseparably bonded from the lower layer.

[0037] In an exemplary embodiment, the multilayer hose assembly may further include a foam thermal insulation layer which is bonded to the lower layer along a portion of the length of the hose, and the foam thermal insulation layer is in intimate contact with, but is unbonded to, the lower layer along another portion of the length of the hose.

[0038] In an exemplary embodiment, the multilayer hose assembly may exhibit a minimum bend radius same as an identical hose without the foam thermal insulation layer.

[0039] In an exemplary embodiment, the multilayer hose assembly may exhibit a minimum bend radius which is between 5-35% smaller than an identical hose without the foam thermal insulation layer.

[0040] In an exemplary embodiment, the multilayer hose assembly may further include a fitting, wherein the fitting has a push-in barb design without any outer shell; and wherein the push-in fitting is inserted into the hose with a force equal to or less than 350 N at an insertion depth equal to or less than 30 mm.

[0041] In an exemplary embodiment, the multilayer hose assembly may further include fitting which is retained by the hose at operating pressures equal to or less than 80 bar and operating temperatures equal to or less than 150°C without utilizing external clamps or crimping or any mechanical fasteners.

[0042] In an exemplary embodiment, the multilayer hose assembly which may upon internal pressurization exhibit a change in length from 0% to +3%.

[0043] In an exemplary embodiment, the multilayer hose assembly may further include a first multilayer hose assembly of any of claims 1 -31 which is bound or fastened to at least one second hose assembly of any of claims 1 -31 in a hose bundle.

[0044] In an exemplary embodiment, the multilayer hose assembly may be formed by a method of forming and integrating a polymer foam thermal insulation layer with other hose layers during hose manufacturing, comprising the steps of: a) using an extruder to form a first thermoset layer; b) using a braider to form a reinforcement layer surrounding the first thermoset layer; c) using an extruder to form a thermoplastic elastomer into a foam thermal insulation layer, wherein the foam thermal insulation layer surrounds the reinforcement layer; and optionally, the temperature of foam extrudate and surface temperature of reinforcement layer are separately controlled and set such that a strong bond is formed between the reinforcement layer and foam thermal insulation layer; and d) curing the first thermoset layer; wherein the steps a) through d) are performed sequentially in a single pass.

[0045] In an exemplary embodiment, the multilayer hose assembly may be formed by a method of forming and integrating a polymer foam thermal insulation layer with other hose layers during hose manufacturing, comprising the steps of: a) using an extruder to form a first thermoset layer on a solid mandrel; b) using a braider to form a reinforcement layer surrounding the first thermoset layer; c) using an extruder to form a first thermoplastic layer surrounding the reinforcement layer; d) using an extruder to form a thermoplastic elastomer into a foam thermal insulation layer, wherein the foam thermal insulation layer surrounds the first thermoplastic layer; and optionally, the temperature of foam extrudate and surface temperature of thermoplastic layer are separately controlled and set such that a strong bond is formed between the thermoplastic layer and foam thermal insulation layer; e) using an extruder to form a protective cover surrounding the foam thermal insulation layer; f) curing the first thermoset layer; g) removing the protective cover to expose the outer surface of the foam thermal insulation layer; and h) removing the solid mandrel to create a hollow conduit at the center of the hose; wherein the steps a) through f) are performed sequentially in a single pass.

[0046] In an exemplary embodiment, the multilayer hose assembly may be formed by a method of forming and integrating a polymer foam thermal insulation layer with other hose layers during hose manufacturing, comprising the steps of: a) using an extruder to form a first thermoset layer on a solid mandrel; b) using a braider to form a reinforcement layer surrounding the first thermoset layer; c) using an extruder to form a second thermoset layer surrounding the reinforcement layer; d) using an extruder to form a thermoplastic elastomer into a foam thermal insulation layer, wherein the foam thermal insulation layer surrounds the second thermoset layer; and optionally, the temperature of foam extrudate and surface temperature of second thermoset layer are separately controlled and set such that a strong bond is formed between the thermoset layer and foam thermal insulation layer; e) curing the first thermoset layer and the second thermoset layer; and f) removing the solid mandrel to create a hollow conduit at the center of the hose; wherein the steps a) through e) are performed sequentially in a single pass.

[0047] In an exemplary embodiment, the multilayer hose assembly may be formed by a method wherein a minimum bond strength of 1.5 N / mm is effected between the foam thermal insulation layer and an adjacent lower layer.

[0048] In an exemplary embodiment, the multilayer hose assembly may be formed by a method wherein an inseparable bond is created between the foam thermal insulation layer and a lower layer.

[0049] In an exemplary embodiment, the multilayer hose assembly may be formed by a method, wherein a temperature of foam extrudate or surface temperature of an adjacent lower layer or both are sequentially, periodically or arbitrarily varied in order to vary the bond strength between the foam thermal insulation layer and a lower layer.

[0050] In an exemplary embodiment, the multilayer hose assembly may be formed by a method, wherein the foam thermal insulation layer is bonded to a lower layer along a portion of the length of the hose; and the foam thermal insulation layer is in intimate contact with, but is unbonded to, the lower layer along another portion of the length of the hose.

[0051] To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

[0052] Brief Description of the Drawings

[0053] Embodiments of this current application will now be described in further detail with reference to the accompanying drawings, in which: FIG. 1 is a drawing depicting a radial cross-sectional view of a first embodiment of the hose of the present application, wherein a first thermoset layer is surrounded by a reinforcement layer, which is in turn surrounded by an insulating layer.

[0054] FIG. 2 is a drawing depicting a longitudinal cut-away view of the embodiment of FIG. 1.

[0055] FIG. 3 is a drawing depicting a radial cross-sectional view of a second embodiment of the hose of the present application, wherein a first thermoset layer is surrounded by a reinforcement layer, which is in turn surrounded by a second thermoset layer, which is in turn surrounded by an insulating layer,

[0056] FIG. 4 is a drawing depicting a radial cross-sectional view of a third embodiment of the hose of the present invention, wherein a first thermoset layer is surrounded by a reinforcement layer, which is in turn surrounded by a thermoplastic layer, which is in turn surrounded by an insulating layer.

[0057] FIG. 5 is a drawing depicting an elevational cross-sectional view of two hoses representing the embodiment of FIG. 6.

[0058] FIG. 6 is a drawing depicting a radial cross-sectional view of a fourth embodiment of the hose of the present invention, wherein a first thermoset layer is surrounded by a reinforcement layer, which is in turn surrounded by a second thermoset layer, which is in turn surrounded by a thermoplastic layer, which is in turn surrounded by an insulating layer.

[0059] FIG. 7 is a drawing depicting a radial cross-sectional view of multiple hoses bundled together by a carrier.

[0060] Detailed Description

[0061] Embodiments of the present application will now be described with refence to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be understood that the figures are not necessarily to scale.

[0062] Embodiments of the present application provide an improved hose assembly for use in medium to high temperature (50°C up to 160°C) hydraulic applications that are more durable, more cost-effective, and easier to produce as compared to conventional configuration. The hose design of the current application constitutes a hybrid hose that may include thermoset, reinforcement, and thermoplastic layers with an integrated polymer foam thermal insulation layer for thermal management and hose protection. Referring to FIGS. 1 and 2, an embodiment of the hose assembly 1 includes a tubular first thermoset layer 3, which is shaped and sealed to transport heated fluid. A reinforcement layer 5 surrounds the first thermoset layer 3. A polymer foam thermal insulation layer 7 surrounds the reinforcement layer 5 to protect the hose 1 and to reduce heat transmittal out of the hose assembly 1 . The foam thermal insulation layer 7 is integrated with other hose layers during the hose manufacturing process and may be bonded to the reinforcement layer 5 to prevent delamination of the foam thermal insulation layer 7 during hose assembly 1 use. In the additional embodiments described below, like reference numerals are used to identify like components. A fitting 13 may attach to an end of the hose assembly configuration. The fitting 13 may be configured as a push-in fitting that includes a barb 15 which contacts the innermost thermoset hose layer. The push-in fitting may lack any shell outside of or surrounding the barb or outside of or surrounding the hose assembly.

[0063] Referring now to FIG. 3, an embodiment of the hose assembly 1 includes a tubular first thermoset layer 3, which is shaped and sealed to transport heated fluid. A reinforcement layer 5 surrounds the first thermoset layer 3, and a second thermoset layer 9 surrounds the reinforcement layer 5. The first and second thermoset layers 3, 9 may share the same chemical composition, or may be different thermoset elastomers.

[0064] Further in the embodiment of Fig. 3, a polymer foam thermal insulation layer 7 surrounds the second thermoset layer 9. The thermal insulation layer 7 is integrated with the hose during the manufacturing process and is bonded to the second thermoset layer 9 to prevent delamination of the thermal insulation layer 7 during hose assembly 1 use.

[0065] Referring to FIGS.4-5, an embodiment of the hose assembly 1 includes a tubular first thermoset layer 3, which is shaped and sealed to transport heated fluid. A reinforcement layer 5 surrounds the first thermoset layer 3. A thermoplastic layer 11 surrounds the reinforcement layer 3 to further improve mechanical property of hose assembly 1 . A polymer foam thermal insulation layer 7 surrounds the thermoplastic layer 11 . The thermal insulation layer 7 is integrated with the hose 1 during the manufacturing process and is bonded to the thermoplastic layer 11 to prevent delamination of the thermal insulation layer during hose 1 use. The thermal insulation layer 7 may be formed from the same thermoplastic material as the thermoplastic layer 11 , or the thermal insulation layer may be formed from a different material than the thermoplastic layer 11 .

[0066] Referring to FIG. 6, an embodiment of the hose assembly 1 includes a tubular first thermoset layer 3, which is shaped and sealed to contain heated fluid. A second reinforcement layer 5 surrounds the first thermoset layer 3. A second thermoset layer 9 surrounds the reinforcement layer 5 to further improve mechanical property of hose assembly 1 . The first and second thermoset layers 3, 9 may share the same chemical composition, or may be different thermoset elastomers.

[0067] A thermoplastic layer 11 surrounds the second thermoset layer 9, and a polymer foam thermal insulation layer 7 surrounds the thermoplastic layer 11 . The foam thermal insulation layer 7 is integrated with the hose 1 during the manufacturing process and is bonded to the thermoplastic layer 11 to prevent delamination of the foam thermal insulation 7 layer during hose assembly 1 use. The thermal insulation layer 7 may be formed from the same thermoplastic material as the thermoplastic layer 11 , or the foam thermal insulation layer 7 may be formed from a different material than the thermoplastic layer 11 .

[0068] The inner and outer radius of each hose 1 layer may be consistent throughout the length of the hose, thereby promoting smooth flow of fluid through the hose 1 while maintaining optimal flexibility of the hose assembly 1 . Alternatively, only the inner and outer radius of the first thermoset hose layer 3 may be consistent throughout the length of the hose assembly 1 .

[0069] The embodiments discussed in Fig. 1 -7 are non-limiting and those skilled in the art can envision different configurations by adding or subtracting layers within the hose to provide additional features, for example, an additional cover over the thermal insulation layer 7 to further protect the thermal insulation during aggressive use in an application or when the hose is subjected to an aggressive environment.

[0070] Within the embodiments discussed in this disclosure, the thermoset layers 3, 9 may be made from a thermoset elastomer. Some examples of thermoset elastomers are natural polyisoprene, synthetic polyisoprene, polybutadiene, chloroprene, butyl rubber, halogenated butyl rubber, styrene-butadiene rubber, nitrile rubber, hydrogenated butyl rubber, ethylene propylene rubber, ethylene propylene diene rubber, silicone rubber, fluorosilicone rubber, fluoroelastomers such as FKM, perfluoroelastomers such as FFKM, chlorosulfonated polyethylene.

[0071] The use of thermoset elastomers ethylene propylene rubber (EPM) and ethylene propylene diene rubber (EPDM) in a hose is common but these materials suffer from limitations, for example, the maximum continuous operating temperature for EPM and EPDM rubber is 120°C. Hence, another object of the present invention is the thermoset elastomer formulation comprising EPM and / or EPDM rubber such that the maximum continuous operating temperature is increased by 20-30°C to achieve a value of 150- 160°C.

[0072] An example of a thermoset composition used in the present invention is discussed in Table 1. The concentration of individual components is described in parts per hundred dubber (phr) which is a commonly used unit in the rubber industry. The thermoset elastomer formulation may comprise up to 100 phr EPM rubber and up to 50 parts EPDM rubber. The rubber is reinforced by using carbon black up to 150 phr along with other additives as mentioned in Table 1 . The curing is achieved by using a peroxide-based curating system. Alternatively, the curing is achieved by using a sulfurbased system. Alternatively, the curing is achieved by a combination of peroxide-based and sulfur-based systems.

[0073] Additionally, the layers may include functional additives, process aids, crosslinking agents, and initiators and crosslinking promoters in optimized proportions to produce a rubber compound that provides favorable properties to the hose.

[0074] The reinforcement layer 5 may comprise of a braid design. A braid can be made by utilizing different materials known in the art including, but not limited to, fibers and yams such as polyester fibers, polyamide fibers, polyaramid fibers, carbon fibers, glass fibers, mineral fibers; uncoated metal and metal alloy wires such as steel, copper, brass; or metal and metal alloy wires with additional coatings such as zinc, brass etc.

[0075] The braid material and braid design can have a major impact on the mechanical performance of the hose assembly. Some desirable mechanical attributes of a hose are high burst pressure, high flexibility, minimum bend radius, limited dimensional change upon pressurization, fatigue resistance under cyclic motion and pressurization, low fitting insertion force, and fitting retention at demanding operating conditions such as high pressure and high temperature. While it is possible to achieve one or more desirable attributes, for example a high burst pressure and a limited dimensional change, by aptly choosing the braid material and braid design, it is not possible to achieve an optimized set of all desirable attributes by selection of the braid material and braid design alone. Hence the choice of braid design and braid material must be coupled with the core tube layer material in order to optimize the mechanical performance of the hose such that several or all mechanical attributes are achieved.

[0076] An example of the braid material used in the present invention is polyaramid yarn. The polyaramid yarn is made by combining fibers or filaments of para-aramid polymer such that the tensile strength of the yarn is between 100-300 Newtons per ASTM D2256 test standard. Alternately, the polyaramid yam is made by combining fibers or filaments of meta-aramid polymer such that the tensile strength of the yarn is between 100-300 Newtons per ASTM D2256 test standard.

[0077] The reinforcement layer 5 may have a braid design with an angle of 50-60 degrees normal to the hose length, and may have a coverage area of the outer surface of first thermoset layer between 35-55 %.

[0078] The combination of thermoset elastomer formulation of the first layer, reinforcement material and reinforcement layer design may allow the hose to exhibit a change in length from 0% to +3% upon pressurization of the hose 1 to at least 20 bar operating pressure per ISO 6605 or ISO 1402 test standards. As a result of positive elongation of the hose during operation, the hose is pushed towards the end fittings instead of being pulled away from the end fittings thereby eliminating the risk of fitting pullout during operation. As a result fitting retention is possible at operating conditions of medium to high temperatures, ranging upwards from 50°C to 160°C, and high pressures, ranging from 20 bar up to 80 bar, without utilizing external clamps or crimping or any mechanical fastener. Consequently, a push-in barb fitting design without any outer shell may be employed for the end fittings.

[0079] Additionally, the combination of thermoset elastomer formulation of the first layer, reinforcement material, and reinforcement layer design may restrict the force required to insert a fitting into the hose to less than 350 Newton up to a minimum fitting insertion depth of 30 mm.

[0080] The reinforcement layer 5 may alternately comprise of a spirally wound layer. A spiral winding can comprise different materials known in the art including, but not limited to, fibers and yarns such as polyester fibers, polyamide fibers, polyaramid fibers, carbon fibers, glass fibers, mineral fibers; uncoated metal and metal alloy wires such as steel, copper, brass; or metal and metal alloy wires with additional coatings such as zinc, brass etc.

[0081] The reinforcement layer 5 may alternately include a first reinforcement section in contact with a second reinforcement section. The first reinforcement section is spirally wound on the inner thermoset layer, and the second reinforcement section may be spirally wound on the first reinforcement section. The second reinforcement section may be wound in an opposite direction to the first reinforcement section. The angle of winding of the two reinforcement sections may be different or same. For example, both the first and second reinforcement sections of the reinforcement layer 5 are wound at an angle of 50-60 degrees normal to the hose length but in opposite directions.

[0082] The polymer foam thermal insulation layer 7 may be any thermoplastic elastomer foam with insulative properties. The thermal insulation layer 7 may be formed by converting a thermoplastic elastomer polymer into a foam by introducing voids within the thermoplastic elastomer polymer. The thermoplastic elastomer may be chosen from a family of styrenic block copolymers, thermoplastic polyolefinelastomers, thermoplastic vulcanizates, thermoplastic polyurethanes, thermoplastic copolyesters, thermoplastic co-polyamides, and other block copolymers. In a preferred embodiment the thermoplastic elastomer may be a thermoplastic polyurethane (TPU) copolymer formed with the reaction of an isocyanate, a long-chain alcohol (also referred to as a polyol), and short chain alcohols or short chain amines (also referred to as chain extenders). In an example of the thermoplastic polyurethane used for making the foam thermal insulation layer 7, the thermoplastic polyurethane is formed with the reaction of an aromatic isocyanate with an aliphatic polyol. The aromatic isocyanate may be a diisocyanate, that is it has a reactive functionality of 2 to produce linear TPU polymer chains. The chain extender may be a diol or a diamine, that is it has a reactive functionality of 2 to produce linear TPU polymer chains. Either aliphatic or aromatic chain-extenders may be used. The polyol may be a polyether-polyol, and therefore the TPU polymer can be classified as a polyether-polyurethane copolymer. The polyol may have a molecular weight between 3000-6000 gm / mol.

[0083] In another example of the thermoplastic polyurethane used for making the foam thermal insulation layer 7, the thermoplastic polyurethane is formed with the reaction of an aliphatic isocyanate with an aliphatic polyol. In another embodiment, the thermoplastic polyurethane is formed with the reaction of an aliphatic isocyanate with an aryl polyol. In another embodiment, the thermoplastic polyurethane is formed with the reaction of an aromatic isocyanate with an aromatic polyol. Either aliphatic or aromatic chain-extenders can be used in the above embodiments. In another embodiment, a mixture of isocyanates with functionalities of 2, 3, or more could be used thereby resulting in a mixture of linear, branched or cross-linked polymer chains. In yet another embodiment, a mixture of diols or diamines with functionalities of 2, 3, or more could be used thereby resulting in a mixture of linear, branched or cross-linked polymer chains. In yet another embodiment, the polyol used in the synthesis of thermoplastic urethane is a polyester polyol, and therefore the TPU polymer can be classified as a polyester-polyurethane copolymer. In an embodiment, the polyol used in the synthesis of thermoplastic urethane may have a molecular weight between 500-12000 gm / mol.

[0084] The thermoplastic elastomer used for making the foam thermal insulation layer 7 may incorporate up to 20% by weight of certain additives to enhance its properties and operational performance including, but not limited to, plasticizers, compatibilizers, antioxidants, UV stabilizers, radiopaque compounds, colorants (pigments or dyes), flow modifiers, impact modifiers, elastomers (such as in thermoplastic elastomers), crosslinked rubber (such as in thermoplastic vulcanizates), lubricants, releasing agents, coupling agents, cross-linking agents, dispersing agents, foam nucleating agents, flame retardants, reinforcing metals, minerals, nucleating agents, and / or fillers (such as talc, clay, mica, graphite, carbon black, carbon nanotubes, graphene, silica, POSS, powdered metals, powdered ceramics, metal or ceramic based nanowires, glass fibers etc.). Another embodiment of the thermoplastic elastomer resin may include a combination of any of the listed additives.

[0085] The polymer foam thermal insulation 7 may be formed by introducing voids within the thermoplastic elastomer polymer through a foam extrusion process using an extruder. The foam extrusion process involves mixing the base polymer such as thermoplastic polyurethane copolymer with a foaming agent inside the extruder and maintaining high pressure inside the extruder and downstream tooling such as adapters and dies until the extrudate exits the extruder assembly.

[0086] The polymer foam thermal insulation 7 may be formed using a chemical foam extrusion process. In such a process a chemical foaming agent is used which undergoes a thermal decomposition reaction inside the extruder to yield gases such as CO2, N2 etc. The decomposition chemical reaction is activated at a target temperature and the release of gas or a mixture of gases is followed by mixing of such gases with the polymer melt. The gases are kept dissolved in the polymer melt by maintaining high pressure inside the extruder assembly until the polymer melt exits the extruder, upon which the dissolved gas phase-separates from the polymer melt and causes the polymer to expand into a foam.

[0087] Examples of chemical foaming agents include, but are not limited to, Citric acid / Sodium bicarbonate, ADCA (Azodicarbonate), OBSH (p,p’-Oxybis (benzene) sulfonyl), TSH (p-Toluene sulfonyl hydrazide), TSS (p-Toluene sulfonyl semicarbazide), DNPT (Dinitrosopentamethylenetetramine), 5PT (5-Phenyltetrazole), SBH (Sodium borohydride), Magnesium carbonate (MgCOa), Calcium carbonate (CaCOs), Zinc carbonate (ZnCOs), a combination of MgCOs, CaCOs, and ZnCOs, tartaric acid, azodicarbonamide, a hydrazine derivative, a semi-carbazide derivative, a tetrazole derivative, a benzoxazine derivative, a metal oxide derivative or a metal carbonate derivative. The chemical foaming agent may also include a combination of any of the listed chemicals.

[0088] Alternately, the polymer foam thermal insulation 7 may be formed using a physical foam extrusion process. Such a process involves direct injection of the gas (or combination of gases) in supercritical state into the polymer melt inside the extruder so that a chemical decomposition reaction is not needed to produce a foam. The gas injection is then followed by mixing the gas with polymer melt at high operating pressures. The gases are kept dissolved in the polymer melt by maintaining high pressure inside the extruder assembly until the polymer melt exits the extruder, upon which the dissolved gas phase-separates from the polymer melt and causes the polymer to expand into a foam.

[0089] Examples of physical foaming agents include, but are not limited to, Propane (CsHs), n-Butane (C4H10), i-Butane (CH3(CH3)CHCH3), n-pentane (C5H12), i-Pentane (CH3(CH3)CHCH2CH3), HCFC-22 (CHF2CI), HCFC-142b (CHF2CICH3), HFC-152a (CHF2CH3), HCFC-123 (CHCI2CF3), HCFC-123a (CHFCICF2CI), HCFC-124 (CHFCICF3), HFC-134a (CH2FCF3), HFC-143a (CH3CF3), CFC-11 (CFCI3), CFC-12 (CF2CI2), CFC-113 (CFCI2CF2CI), CFC-114 (CF2CLCF2CI), MeCI (CH3CI), MeCI2(CH2CI2), Carbon dioxide (CO2), Nitrogen (N2), Oxygen (O2), supercritical CO2, air, helium, argon, aliphatic hydrocarbons (e.g., butanes, pentanes, hexanes, and heptanes), chlorinated hydrocarbons (e.g., dichloromethane and trichloroethylene), and hydrochlorofluorocarbons (e.g., dichlorotrifluoroethane). In certain cases, combination or mixture of any of the above gases could be utilized as physical foaming agents. The thermoplastic elastomer foam so formed may exhibit a density reduction compared to the unfoamed thermoplastic elastomer of greater than 50 wt%, for example between 50-80%. “Density reduction" may be understood to mean a percentage reduction in the density of a foamed material, based on the density of the non-foamed starting material measured under the same environmental conditions. The foam density may be equal to or less than 0.55 g / cm3, for example between 0.20-0.55 g / cm3.

[0090] The thermoplastic elastomer foam may further exhibit a thermal conductivity reduction compared to the unfoamed thermoplastic elastomer of greater than 60 wt%, for example between 60-90%. “Thermal conductivity reduction" may be understood to mean a percentage reduction in thermal conductivity of a foamed material, based on the thermal conductivtiy of the non-foamed starting material measured under the same environmental conditions. The thermal conductivity of foam may be equal to or less than 0.050 W / m / K, for example between 0.015-0.050 W / m / K.

[0091] The thermoplastic elastomer foam may preferably exhibit a closed cellular morphology and a majority - of the polymer foam voids or cellsare not interconnected. In an alternative embodiment, the thermoplastic elastomer foam may exhibit a semi-closed cellular morphology such that less than 30% of total foam voids or cells are interconnected.

[0092] The cellular morphology of the thermoplastic elastomer foam may be classified as macrocellular characterized by an average void or cell diameter of 100 microns (pm) or greater. Alternatively, the cellular morphology of the thermoplastic elastomer foam may be classified as microcellular characterized by an average cell diameter between 1 micron and 100 microns. Alternatively, the cellular morphology of the thermoplastic elastomer foam may be classified as ultramicrocellular characterized by an average cell diameter anywhere from 0.1 microns to 1 microns. For calculating the average cell diameter, size ranges than span these classifications may also be possible. For example, the thermoplastic elastomer foam may have a cell diameter distribution between 40 microns and 150 microns. In another embodiment, the cell diameter distribution may be between 20 microns and 120 microns. In yet another embodiment, the cell diameter distribution may be between 20 microns and 200 microns. The thermoplastic elastomer foam may exhibit a maximum flexural modulus of 20 MPa per ASTM D790 test standard. In an embodiment the thermoplastic elastomer foam has a flexural modulus between 5 and 10 MPa, or between 10-20 MPa.

[0093] Furthermore, the thermoplastic elastomer foam may exhibit a high abrasion resistance and withstand 2000 abrasion cycles with a maximum loss of 0.05gm when subjected to an abrasion test per ISO 6945:1991 with a vertical force of 25N. In an alternative embodiment, the thermal insulation layer may withstand 3000 abrasion cycles with a maximum loss of 0.01 gm when subjected to an abrasion test per ISO 6945:1991 with a vertical force of 25N.

[0094] The thermoplastic elastomer foam may exhibit a minimum tear resistance of 50 kilo-Newton per meter (kN / m) per ISO 34-1. B test standard. In an embodiment the tear resistance is between 50-150 kN / m, or between 150-200 kN / m.

[0095] In the present invention, the mechanical and thermal properties of thermoplastic elastomer foam thermal insulation are optimized particularly for hose and tubing applications by an optimal selection of the thermoplastic elastomer used for converting into a foam, as well as the final attributes of the foam which are controlled by controlling the operating conditions of the foam extrusion process, type of foaming agent and concentration of foaming agent. For example, in a preferred embodiment of the thermoplastic elastomer foam, the thermoplastic elastomer base resin is a thermoplastic polyurethane synthesized with the reaction of an aromatic isocyanate with an aliphatic polyol along with chain extenders. The aromatic isocyanate is a diisocyanate with a reactive functionality of 2, and the chain extender is a diol or diamine also with a reactive functionality of 2, such that linear TPU polymer chains are formed. The polyol is a polyether-polyol with a molecular weight between 3000-6000 gm / mol, hence the thermoplastic polyurethane is a polyether-polyurethane copolymer. The base polymer is converted into a polymer foam through a chemical foam extrusion process by utilizing a chemical foaming agent that undergoes an endothermic decomposition reaction to release carbon dioxide gas. The thermoplastic polyurethane foam so produced exhibits a closed cellular morphology with an average cell diameter of 70 microns, and a cell diameter distribution of 40-120 microns. This thermoplastic polyurethane foam exhibits a density of 0.50 g / cc corresponding to a density reduction of 55%.

[0096] As a consequence of controlling the chemical composition of the base thermoplastic polyurethane polymer as well as the cellular morphology and density of the polymer foam so produced, the polymer foam exhibits a flexural modulus of 10-15 MPa, a tear resistance of 120-150 kN / m, an abrasion resistance corresponding to 0.01 gm mass loss at 3000 abrasion cycles, and a thermal conductivity of 0.050 W / m / K which corresponds to a thermal conductivity reduction of 75% compared to the unfoamed thermoplastic polyurethane.

[0097] Referring to the hose assembly embodiment in Figure 3, the thermoplastic layer 11 may be formed from a thermoplastic elastomer. The thermoplastic elastomer may be chosen from a family of styrenic block copolymers, thermoplastic polyolefinelastomers, thermoplastic vulcanizates, thermoplastic polyurethanes, thermoplastic copolyesters, thermoplastic co-polya ides, and other block copolymers. n a preferred embodiment, the thermoplastic layer 11 is similar in composition to the thermoplastic polymer foam thermal insulation layer 7, for example the thermoplastic layer 11 comprises a thermoplastic polyurethane.

[0098] The thermoset 3, 9 and thermoplastic 11 layers of the hose design of the current application may be formed using a standard polymer extruder. The reinforcement layer 5 may be formed using a standard braider. The foam thermal insulation 7 may be formed by a foam extrusion process using an extruder.

[0099] Typically for manufacturing a thermally insulated hose assembly, the thermal insulations are firstly manufactured in a separate step, and then incorporated on or within a hose assembly in a second step by cutting the thermal insulation to a certain length and wrapping it around the hose. Such a practice involves extensive manual labor which is costly, time-consuming, and decreases efficiency of manufacturing a hose assembly. Therefore, another objective of the present invention is to “integrate” the thermal insulation during the hose manufacturing process itself, thereby decreasing the time, cost and complexity, and increasing the process and operational efficiency of manufacturing a thermally insulated hose assembly. The hose design of the current application involves creating all the layers including thermoset, thermoplastic, reinforcement, and thermoplastic elastomer foam consecutively in a single pass followed by simultaneous curing process.

[0100] In an exemplary embodiment, the hose may be formed by a method comprising the steps of using an extruder to form the first layer comprising a thermoset polymer formulation; using a braider to form the reinforcement layer on the first layer; using an extruder to form a layer comprising thermoplastic polymer foam thermal insulation on top of the reinforcement layer; curing the thermoset polymer formulation of the first layer; wherein the above steps are performed sequentially in the aforementioned order.

[0101] In another exemplary embodiment, the hose may be formed by a method comprising the steps of using an extruder to form the first layer comprising a thermoset polymer formulation on a mandrel; using a braider to form the reinforcement layer on the first layer; using an extruder to form a layer comprising thermoplastic polymer on top of the reinforcement layer; using an extruder to form a layer comprising thermoplastic polymer foam thermal insulation on top of the thermoplastic layer; using an extruder to form a protective layer on top of the thermal insulation layer; curing the thermoset polymer formulation of the first layer; removing the protective layer to expose the outer surface of the thermal insulation layer; removing the innermost mandrel to create a hollow conduit at the center of the hose; wherein the above steps are performed sequentially in the aforementioned order.

[0102] In another exemplary embodiment, the hose may be formed by a method comprising the steps of using an extruder to form the first layer comprising a thermoset polymer formulation on a mandrel; using a braider to form the reinforcement layer on the first layer; using more than one extruder in a co-extrusion process to form a coextruded layer comprising thermoplastic polymer as the inner layer and thermoplastic polymer foam thermal insulation as the outer layer of the co-extruded layer; using an extruder to form a protective layer on top of the thermal insulation layer; curing the thermoset polymer formulation of the first layer; removing the protective layer to expose the outer surface of the thermal insulation layer; removing the innermost mandrel to create a hollow conduit at the center of the hose; wherein the above steps are performed sequentially in the aforementioned order. In another exemplary embodiment, the hose may be formed by a method comprising the steps of using an extruder to form the first layer comprising a thermoset polymer formulation on a mandrel; using a braider to form the reinforcement layer on the first layer; using an extruder to form a layer comprising thermoplastic polymer on top of the reinforcement layer; using an extruder to form a protective layer on top of the thermoplastic layer; curing the thermoset polymer formulation of the first layer; removing the protective layer to expose the outer surface of the thermoplastic layer; removing the innermost mandrel to create a hollow conduit at the center of the hose; using an extruder to form a layer comprising thermoplastic polymer foam thermal insulation on top of the thermoplastic layer; wherein the above steps are performed sequentially in the aforementioned order.

[0103] In another exemplary embodiment, the hose may be formed by a method comprising the steps of using an extruder to form the first layer comprising a thermoset polymer formulation on a mandrel; using a braider to form the reinforcement layer on the first layer; using an extruder to form a second layer comprising thermoset polymer formulation on top of the reinforcement layer; using an extruder to form a layer comprising thermoplastic polymer foam thermal insulation on top of the second thermoset layer; using an extruder to form a protective layer on top of the thermal insulation layer; curing the thermoset polymer formulation of the first and second layers; removing the protective layer to expose the outer surface of the thermal insulation layer; removing the innermost mandrel to create a hollow conduit at the center of the hose; wherein the above steps are performed sequentially in the aforementioned order.

[0104] Alternatively, the hose of the current application can be manufactured by a second method, wherein a first thermoset layer 3 is formed and then fully cured before any additional thermoset layer 9, thermoplastic layer 11 , or foam thermal insulation layer 7 is applied in a single pass. The layers applied after the first thermoset layer 3 are all simultaneously cured at a later time than the first thermoset layer 3.

[0105] It is generally important during field operation that the multiple layers within a hose remain intact and well-bonded to each other. Any delamination of the multiple layers within a hose during operation could result in premature failure. The typical standard method of separately manufacturing a thermal insulation and later incorporating it into the hose assembly for thermally insulating the hose assembly suffers from a major drawback of poor or no bonding between the insulation layer and surrounding layers of the hose. Hence external provisions such as the use of an adhesive layer are needed to provide a strong and uniform bond between insulation layer and surrounding layers. Generally, the adhesive layer is applied at a slit made along the length of the insulation so that the insulation can be tightly wrapped on an underlying layer of the hose and held intact at the slit. However, this method of tightly holding the insulation on an underlying layer is not very effective. Delamination may eventually occur in a dynamic operation where the hose undergoes cyclic motion, such as a back-and-forth motion in a forklift or a molding machine. Any attempts to prevent delamination then involves a uniform application of adhesive along the entire length and inner or outer surface of the insulation. Such post-manufacturing assembly steps are extremely tedious, time-consuming, requires precision and adds complexity to the manufacturing of hose assembly. Hence another objective of the present invention is to eliminate such limitations in a thermally insulated hose assembly.

[0106] In the present invention, the manufacturing of thermal insulation is “integrated” within the manufacturing of a hose by extruding a polymer foam layer directly on top of the underlying hose layer, thereby, simplifying the incorporation of thermal insulation. Within this process the temperature of foam extrudate and the surface temperature of the underlying layer may be separately controlled and optimized such that a very strong bond is formed between the two layers once the two layers are cooled down to much lower temperatures. Therefore the use of chemical adhesives or additional tie layers is not required to form a strong bond between the thermal insulation layer and the underlying hose layers, for example layers 5, 7, 9 in Figures 1 -8. Hence the hose manufacturing is simpler, faster, productivity is higher, hose design is more robust, and the operational performance is more reliable than conventional thermally insulated hoses.

[0107] The chemical composition of the thermal insulation layer 7, chemical composition of the underlying hose layers 3, 5 or 9, temperature profile of the foam extrusion process, temperature of the polymer foam extrudate, as well as surface temperature profile of the underlying hose layers 3, 5 or 9 may be chosen so that the thermal insulation layer bonds strongly to its adjacent hose layers. In an embodiment, the foam thermal insulation layer may exhibit a minimum bond strength of 1 .5 N / mm with the underlying layer per ISO 8033 test standard. In another embodiment, the foam thermal insulation layer may exhibit a bond strength of 10 N / mm per ISO 8033 test standard. In another embodiment, an inseparable bond may be created between the foam thermal insulation layer and the underlying hose layer, which means that the two layers can no longer be separated at their interface.

[0108] In an example of the hose embodiment described in Figure 3, the thermoplastic layer 9 may comprise a thermoplastic polyurethane elastomer. The foam thermal insulation 7 may also comprise a thermoplastic polyurethane elastomer. The thermoplastic polyurethane of both layers 9 and 7 is a polyether-polyurethane copolymer and identical. A chemical foam extrusion process is used to convert the thermoplastic polyurethane into foam thermal insulation layer 7, and to cover the underlying thermoplastic polyurethane layer 9 with the foam thermal insulation layer 7. The temperature of the thermoplastic polyurethane layer 9 is maintained at a temperature which is 50°C lower than the peak melting point of thermoplastic polyurethane. The temperature of the thermoplastic polyurethane foam layer 7 is maintained at a temperature which is 10°C lower than the peak melting point of thermoplastic polyurethane. The bond created between the thermoplastic polyurethane layer 9 and foam thermal insulation layer 7 is inseparable.

[0109] In another example of the hose embodiment described in Figure 1 , the reinforcement layer 5 may comprise a braid made of para-aramid yarn. The foam thermal insulation 7 may comprise a thermoplastic polyurethane elastomer, which is a polyether-polyurethane copolymer. A chemical foam extrusion process is used to convert the thermoplastic polyurethane into foam thermal insulation layer 7, and to cover the underlying reinforcement layer 5 with the foam thermal insulation layer 7. The temperature of the reinforcement layer 5 is maintained at a temperature which is 70°C lower than the peak melting point of thermoplastic polyurethane of foam thermal insulation 7. The temperature of the thermoplastic polyurethane foam layer 7 is maintained at a temperature which is 10°C lower than the peak melting point of thermoplastic polyurethane. The bond created between the thermoplastic polyurethane layer 9 and the reinforcement layer 5 is 1 .5 N / mm per ISO 8033 test standard.

[0110] The foam thermal insulation layer 7 may be bonded to the underlying hose layer along at least a portion of the length of the hose assembly. For example, in some embodiments, the foam thermal insulation layer 7 is bonded to the underlying layer along the entire length of the hose assembly. In other embodiments, the foam thermal insulation layer 7 is bonded to the underlying layer at one or more portions along the length of the hose, the sum of the one or more portions being less than the entire length of the hose assembly. For example, the foam thermal insulation layer 7 may extend the entire length of the hose assembly, but may only be bonded at one or more portions along that length. The layering of the described hose allows the foam thermal insulation layer 7 to be designed such that it has no impact or minimal impact on the desirable mechanical properties of hose 1. That is, the hose 1 shall exhibit similar or better mechanical properties compared to the hose with same construction but without any foam thermal insulation layer 7.

[0111] In an embodiment, the minimum bend radius of the described hose assembly is not affected by incorporation of the thermal insulation layer 7. For example, a hose 1 without the foam thermal insulation layer 7 would exhibit a minimum bend radius of 70 mm at a total wall thickness of 3.75 mm and inner diameter of 13 mm per ISO 3949 2020-12 test standard. In contrast, a described hose 1 with the polymer foam thermal insulation layer 7 thickness of 3 mm also exhibits a minimum bend radius of 70 mm at a total wall thickness of 6.75 mm and inner diameter of 13 mm per ISO 39492020-12 test standard.

[0112] In another embodiment, the minimum bend radius of the described hose assembly further reduces by incorporation of the thermal insulation layer 7. For example, a hose 1 without the foam thermal insulation layer 7 would exhibit a minimum bend radius of 70 mm at a total wall thickness of 3.75 mm and inner diameter of 13 mm per ISO 39492020-12 test standard. In contrast, a described hose 1 with the polymer foam thermal insulation layer 7 thickness of 3 mm exhibits a min. bend radius of 60 mm at a total wall thickness of 6.75 mm and inner diameter of 13 mm per ISO 3949 2020-12 test standard. This represents a reduction of 15% in the bend radius of hose 1 . In another embodiment, a reduction of 35% in the bend radius of hose 1 may be achieved with the use of a polymer foam thermal insulation.

[0113] The layering of the described hose design allows the foam thermal insulation layer 7 to be less thick than conventional hoses. Accordingly, the foam thermal insulation layer 7 may have a thickness between 1 mm and 10mm. In an embodiment, the foam thermal insulation layer 7 may have a thickness that provides safe user touch temperatures of about 60°C while the hose transports fluids with a temperature of 150°C. Accordingly, the foam may have a thermal conductivity that is equal to or less than 0.050 W / m / K, or alternatively between 0.015 and 0.050 W / m / K. The thermal insulation layer 7 may decrease the surface temperature of the hose 1 by 70% compared to conventional hoses without thermal insulation and may provide a burn safety rating per specifications of ISO 13732-1 .In an embodiment, the hose 1 without the fittings has a maximum mass of 0.245 kg / m while maintaining a 70% reduction surface temperature. In another embodiment, the hose 1 without the fittings has a mass of less than 0.138 kg / m while maintaining a 70% reduction in surface temperature.

[0114] Fittings may attach to the ends of the hose configuration. The fittings may take the form of a push-in fitting 15 (see Fig. 2) that includes a barb which contacts the innermost thermoset hose layer. The push-in fitting 15 may lack any shell outside of or surrounding the barb or outside of or surrounding the hose 1 . The described combination of the hose assembly 1 layers allows the push-in fitting to have an insertion force of equal to or less than 350 N and up to a fitting insertion depth of 30mm. The minimum tensile strength to separate the hose from a push-in fitting may be 1000N per ISO6605 test standard. The described hose assembly 1 may withstand a minimum of 300,000 impulse cycles in accordance with ISO 6803 at operating conditions of 20 bar, and -20 through 150°C temperatures.

[0115] Table 2 provides fitting insertion force profile as a function of fitting insertion depth for the described hose without the foam insulation layer 7. The force required to insert the push-in fittings 15 is not affected or only minimally affected by the incorporation of of foam thermal insulation layer 7. In an embodiment, a hose 1 without foam thermal insulation layer 7may have a fitting insertion force of less than 12 Newtons per mm of insertion depth up to a total insertion depth of 30 mm. The foam thermal insulation cover 7 may have no effect on the insertion force profile as seen for Case 2 where the density of polymer foam is 0.50 g / cc corresponding to a 55% reduction in density of the unfoamed polymer.

[0116] The described hose assembly 1 may be bound or fastened to other hose assemblies 1 to prevent abrasion between moving hoses. The described hose assemblies 1 may be bound to each other via the assembly’s foam layers 7 or via adhesive. In an embodiment, the described hose assemblies 1 are placed within a cable chain or cable carriage that organizes the hoses and keeps the hoses 1 from rub- induced fatigue. As shown in FIG. 7, a hose bundle may include multiple hoses (individually labeled 1 a, 1b, and 1 c) bundled together by a carrier 17. The carrier 17 may be used to hold the bound or fastened hose assemblies 1 a-c together. The carrier 17 may be a housing, strap, harness, or other structure used for bundling hoses as are known in the art. Different embodiments of the disclosed hose may be bound within the same hose bundle, and an electric power cable or data transmitting cable may optionally be included in the hose bundle as well.

[0117] Embodiments of the present application provide improvements over conventional hose configurations. Because the thermal insulation layer 7 is an integral part of the hose 1 , the described hose assembly eliminates the need to manually install thermal insulation on to a standard hose assembly. Because the hose assemblies of the current application can be assembled layer by layer, the hose surface temperature can be set to avoid injury and / or burns from touching the hose assembly. Similarly, the layer-by- layer construction means that the foam density of the thermal insulation layer can be tailored to the specific application. The thermal insulation layer improves energy efficiency by reducing radiant heat loss, and the thermal insulation may be color coded to identify different fluid lines. Furthermore, the durable nature of the thermoplastic foam layer means that the thermal insulation protects the hose against abrasion, increasing the lifetime of the hose-using assembly. The integral thermal insulation layer allows the described hose assembly to have a tight bend radius and also to be pre-formed.

[0118] It is appreciated that while the hose or tube may in some embodiments have a circular cross-sectional shape, in other embodiments the hose or tube may have a noncircular cross-sectional shape. Non-limiting cross-sectional shapes include an oval, elliptical, triangular, square, pentagon, hexagon, other polygonal shape, and the like.

[0119] Additionally, while the present invention focuses on high temperature applications, those skilled in the art can envision several other applications of the present invention, for example, use of the hose assembly 1 at low to extremely low temperatures (10 °C and lower) where the claimed features provide benefits such as the ability to prevent condensation on the surface of the hose.

[0120] Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above-described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to described such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

Claims

ClaimsWhat is claimed is:1 . A multilayer hose assembly comprising: a hose, wherein the hose is a multilayer construction comprising: a first thermoset layer; at least one reinforcement layer surrounding the first thermoset layer; and a polymer foam thermal insulation layer surrounding the at least one reinforcement layer; wherein the foam thermal insulation layer is inseparably bonded directly to adjacent layers with absence of mechanical ties or adhesives or tie layers.

2. The multilayer hose assembly of claim 1 , wherein the thermoset layer is made from a thermoset elastomer formulation comprising EPM polymer to withstand continuous operating temperature up to 160°C.

3. The multilayer hose assembly of any of claims 1 -2, wherein the thermoset layer is made from a thermoset elastomer formulation comprising a combination of EPM and EPDM polymers to withstand continuous operating temperature equal to or less than 160°C.

4. The multilayer hose assembly of any of claims 1 -3, wherein the at least one reinforcement layer comprises a braid made from polyaramid yarn comprising polyaramid fibers or filaments, such that the yarn has a tensile strength in the range of 100-300 Newton.

5. The multilayer hose assembly of any of claims 1 -4, wherein the at least one reinforcement layer comprises a braid made from polyaramid yam comprising polyaramid fibers or filaments, such that the braid has an angle between 50-60 degrees normal to the hose length, and provides surface coverage of the thermoset layer between 35-55 percent.

6. The multilayer hose assembly of any of claims 1 -5, wherein the at least one reinforcement layer has a first reinforcement section that contacts a second reinforcement section, wherein both the first and second reinforcement sections are spirally wound at an angle between 50-60 degrees normal to the hose length, and the first reinforcement section is wound in an opposite direction relative to the second reinforcement section.

7. The multilayer hose assembly of any of claims 1 -6, wherein the foam thermal insulation comprises voids dispersed within a thermoplastic elastomer, and wherein the thermoplastic elastomer is a thermoplastic polyurethane formed with the reaction of aromatic isocyanate, aliphatic polyol and chain extender.

8. The multilayer hose assembly of claim 7, wherein the thermoplastic polyurethane is a linear polymer, and wherein: the isocyanate has a functionality of 2, the chain extender has a functionality of 2, and the polyol is a polyether-polyol with molecular weight between 3000-6000 gm / mol.

9. The multilayer hose assembly of claim 7, wherein the thermoplastic polyurethane is a linear polymer, and wherein: the isocyanate has a functionality of 2, and the chain extender has a functionality of 2, and the polyol is a polyester-polyol with molecular weight between 500-12000 gm / mol.

10. The multilayer hose assembly of claim 7, wherein the thermoplastic polyurethane is a cross-linked polymer, and wherein: the isocyanate has a functionality higher than 2, or the chain extender has a functionality higher than 2.11 . The multilayer hose assembly of any of claims 1 -10, wherein the foam thermal insulation comprises a closed cell structure.

12. The multilayer hose assembly of any of claims 1 -10, wherein the foam thermal insulation comprises a semi-closed cell structure such that less 30% of voids or cells are interconnected.

13. The multilayer hose assembly of any of claims 1 -12, wherein the foam thermal insulation comprises cells or voids with a diameter in the range of 20-200 microns.

14. The multilayer hose assembly of any of claims 1 -13, wherein the foam thermal insulation has a density of 0.20-0.55 g / cm3.

15. The multilayer hose assembly of any of claims 1 -1 , wherein the foam thermal insulation has a thermal conductivity of 0.015-0.050 W / m / K.

16. The multilayer hose assembly of any of claims 1 -15, wherein the foam thermal insulation exhibits: a density reduction of 50-80% compared to the unfoamed polymer used for creating the foam thermal insulation, and a thermal conductivity reduction of 60-90% compared to the unfoamed polymer used for creating the foam thermal insulation.

17. The multilayer hose assembly of any of claims 1 -16, wherein the foam thermal insulation exhibits a flexural modulus between 5-20 MPa.

18. The multilayer hose assembly of any of claims 1 -17, wherein the foam thermal insulation exhibits a mass loss of 0.01 grams when subjected to 3000 abrasion cycles per ISO 6945:1991 with a vertical force of 25 Newton.

19. The multilayer hose assembly of any of claims 1 -18, wherein the foam thermal insulation exhibits a tear resistance between 50-200 kN / m.

20. The multilayer hose assembly of any of claims 1 -19, further comprising a second thermoset layer which surrounds the reinforcement layer and lies between the reinforcement layer and the foam thermal insulation layer.21 . The multilayer hose assembly of claim 20, wherein the second thermoset layer is chemically identical to the first thermoset layer.

22. The multilayer hose assembly of any of claims 1 -21 , further comprising a thermoplastic layer which surrounds the reinforcement layer and lies between the reinforcement layer and the foam thermal insulation layer.

23. The multilayer hose assembly of any of claims 1 -22, wherein the thermoplastic layer is chemically identical to the foam thermal insulation layer.

24. The multilayer hose assembly of any of claims 1 -23, wherein the foam thermal insulation layer is bonded to the lower layer with a minimum bond strength of 1 .5 N / mm.

25. The multilayer hose assembly of any of claims 1 -23, wherein the foam thermal insulation layer is inseparably bonded from the lower layer.

26. The multilayer hose assembly of any of claims 1-23, wherein the foam thermal insulation layer is bonded to the lower layer along a portion of the length of the hose, and the foam thermal insulation layer is in intimate contact with, but is unbonded to, the lower layer along another portion of the length of the hose.

27. The multilayer hose assembly of any of claims 1 -26, wherein themultilayer hose assembly exhibits a minimum bend radius same as an identical hose without the foam thermal insulation layer.

28. The multilayer hose assembly of any of claims 1 -26, wherein the hose exhibits a minimum bend radius which is between 5-35% smaller than an identical hose without the foam thermal insulation layer.

29. The multilayer hose assembly of any of claims 1 -28, further comprising a fitting, wherein the fitting has a push-in barb design without any outer shell; and wherein the push-in fitting is inserted into the hose with a force equal to or less than 350 N at an insertion depth equal to or less than 30 mm.

30. The multilayer hose assembly of any of claims 1 -29, wherein the fitting is retained by the hose at operating pressures equal to or less than 80 bar and operating temperatures equal to or less than 150°C without utilizing external clamps or crimping or any mechanical fasteners.31 . The multilayer hose assembly of any of claims 1 -30, wherein upon internal pressurization it exhibits a change in length from 0% to +3%.

32. A hose assembly combination comprising a first multilayer hose assembly of any of claims 1 -31 which is bound or fastened to at least one second hose assembly of any of claims 1 -31 in a hose bundle.

33. A method of forming and integrating a polymer foam thermal insulation layer with other hose layers during hose manufacturing, comprising the steps of: a) using an extruder to form a first thermoset layer; b) using a braider to form a reinforcement layer surrounding the first thermoset layer; c) using an extruder to form a thermoplastic elastomer into a foam thermal insulation layer, wherein the foam thermal insulation layer surrounds the reinforcementlayer; and optionally, the temperature of foam extrudate and surface temperature of reinforcement layer are separately controlled and set such that a strong bond is formed between the reinforcement layer and foam thermal insulation layer; and d) curing the first thermoset layer; wherein the steps a) through d) are performed sequentially in a single pass.

34. A method of forming and integrating a polymer foam thermal insulation layer with other hose layers during hose manufacturing, comprising the steps of: a) using an extruder to form a first thermoset layer on a solid mandrel; b) using a braider to form a reinforcement layer surrounding the first thermoset layer; c) using an extruder to form a first thermoplastic layer surrounding the reinforcement layer; d) using an extruder to form a thermoplastic elastomer into a foam thermal insulation layer, wherein the foam thermal insulation layer surrounds the first thermoplastic layer; and optionally, the temperature of foam extrudate and surface temperature of thermoplastic layer are separately controlled and set such that a strong bond is formed between the thermoplastic layer and foam thermal insulation layer; e) using an extruder to form a protective cover surrounding the foam thermal insulation layer; f) curing the first thermoset layer; g) removing the protective cover to expose the outer surface of the foam thermal insulation layer; and h) removing the solid mandrel to create a hollow conduit at the center of the hose; wherein the steps a) through f) are performed sequentially in a single pass.

35. A method of forming and integrating a polymer foam thermal insulation layer with other hose layers during hose manufacturing, comprising the steps of:a) using an extruder to form a first thermoset layer on a solid mandrel; b) using a braider to form a reinforcement layer surrounding the first thermoset layer; c) using an extruder to form a second thermoset layer surrounding the reinforcement layer; d) using an extruder to form a thermoplastic elastomer into a foam thermal insulation layer, wherein the foam thermal insulation layer surrounds the second thermoset layer; and optionally, the temperature of foam extrudate and surface temperature of second thermoset layer are separately controlled and set such that a strong bond is formed between the thermoset layer and foam thermal insulation layer; e) curing the first thermoset layer and the second thermoset layer; and f) removing the solid mandrel to create a hollow conduit at the center of the hose; wherein the steps a) through e) are performed sequentially in a single pass.

36. The method of any of claims 33-35, wherein a minimum bond strength of 1 .5 N / mm is effected between the foam thermal insulation layer and an adjacent lower layer.

37. The method of any of claims 33-35, wherein an inseparable bond is created between the foam thermal insulation layer and a lower layer.

38. The method of any of claims 33-35, wherein a temperature of foam extrudate or surface temperature of an adjacent lower layer or both are sequentially, periodically or arbitrarily varied in order to vary the bond strength between the foam thermal insulation layer and a lower layer.

39. The method of any of claims 33-35, wherein the foam thermal insulation layer is bonded to a lower layer along a portion of the length of the hose; and the foam thermal insulation layer is in intimate contact with, but is unbonded to, the lower layer along another portion of the length of the hose.

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