Air conditioning pipe fittings

Abstract

To provide an air conditioning pipe fitting that can more effectively prevent water penetration from the edges of the foamed layer. [Solution] A joint for an air conditioning pipe 10 which is a multi-layered pipe of two or more layers, comprising a cylindrical foamed layer 11 and a non-foamed inner layer 12 provided on the inner surface of the cylindrical foamed layer 11, wherein a stopper 23 is provided at the back of the receiving portion 21 into which the air conditioning pipe 10 is inserted to restrict the insertion of the air conditioning pipe 10, and a sealing member 40 made of two or more layers including an elastic layer 41 is provided on the restricting surface 23A on the air conditioning pipe 10 side of the stopper 23.

Description

Technical Field

[0001] The present invention relates to a pipe joint for air conditioning.

Background Art

[0002] As an air conditioning pipe (for example, an air conditioning drain pipe), a multilayer pipe having a foam layer and a non-foamed inner layer laminated on the inner surface thereof is preferably used because it is required to have excellent heat insulation properties. In such an air conditioning pipe, since the end of the foam layer is exposed at the pipe joint portion, water easily penetrates from the end. When water penetrates into the foam layer, the heat exchange rate increases and the heat insulation effect decreases. Therefore, in Patent Document 1, a solvent adhesive is applied to the end of the foam layer to cover the end of the foam layer. In Patent Document 2, an annular elastic body is used to prevent water from penetrating into the foam layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the pipe end treatment method of Patent Document 1, it is necessary to apply the solvent adhesive uniformly, but there is a concern of omission of coating. In the connection structure of Patent Document 2, there is a concern of a decrease in adhesion due to cold flow of the elastic body. Moreover, since the air conditioning pipe is cut to an appropriate length by an operator and used, it is difficult to cut the end into a flat planar shape in the orthogonal direction, and irregularities and inclinations are likely to occur at the end. Therefore, in the conventional pipe joint, there is room for improvement in the structure for preventing water from penetrating from the end of the foam layer.

[0005] The present invention has been made in view of the circumstances described above, and aims to provide an air conditioning pipe fitting that can more effectively prevent water from seeping in from the edges of the foamed layer. [Means for solving the problem]

[0006] To solve the aforementioned problems, the present invention proposes the following means. The pipe joint according to the present invention is a joint for an air conditioning pipe which is a multi-layer pipe of two or more layers, comprising a cylindrical foamed layer and a non-foamed inner layer provided on the inner surface of the cylindrical foamed layer, wherein a stopper is provided at the back of the receiving portion into which the air conditioning pipe is inserted to restrict the insertion of the air conditioning pipe, and a sealing member composed of two or more layers including an elastic layer is provided on the restricting surface of the stopper on the air conditioning pipe side. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an air conditioning pipe fitting that can highly prevent water from seeping in from the edges of the foamed layer. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing an air conditioning system in which the air conditioning pipe fitting of the present invention is used. [Figure 2] This is a longitudinal cross-sectional view showing an air conditioning pipe fitting according to an embodiment of the present invention. [Figure 3] This is a longitudinal cross-sectional view showing an air conditioning pipe connected to the socket of an air conditioning pipe fitting according to an embodiment of the present invention. [Figure 4] This figure shows a first modified example of the air conditioning pipe fitting shown in Figure 2. [Figure 5] This figure shows a second modified example of the air conditioning pipe fitting shown in Figure 2. [Modes for carrying out the invention]

[0009] Hereinafter, an air conditioning pipe fitting according to an embodiment of the present invention and a fitting structure using this air conditioning pipe fitting will be described with reference to Figures 1 to 3. In this embodiment, an air conditioning pipe fitting used for air conditioning drains is given as an example, but for example, the air conditioning pipe fitting may be a fitting used for air conditioning refrigerants. As shown in Figure 1, the air conditioning drain pipe fitting 20 according to this embodiment is used in a fitting structure 1 through which drain water from the air conditioning equipment 100 flows. The fitting structure 1 comprises an air conditioning drain pipe 10 and an air conditioning drain pipe fitting 20 to which the air conditioning drain pipe 10 is connected.

[0010] [Air conditioning drain pipe 10] The air conditioning drain pipe 10 is a multi-layered pipe comprising at least two layers: a cylindrical foamed layer 11 and a non-foamed inner layer 12 provided on the inner surface of the foamed layer 11. The air conditioning drain pipe 10 in this embodiment is a three-layered multi-layered pipe comprising a foamed layer 11, a non-foamed inner layer 12, and a non-foamed outer layer 13 provided on the outer surface of the foamed layer 11.

[0011] <Non-foamed inner layer 12> The non-foamed inner layer 12 contains a vinyl chloride resin. The vinyl chloride resin may be a homopolymer of vinyl chloride monomers (polyvinyl chloride), or a copolymer of a vinyl chloride monomer and another monomer copolymerizable with the vinyl chloride monomer. Other monomers copolymerizable with the vinyl chloride monomer mentioned above include, for example, ethylene, propylene, allyl chloride, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, vinyl acetate, maleic anhydride, and acrylonitrile. These may be used individually or in combination of two or more.

[0012] Vinyl chloride resins may be used alone, or two or more types may be used in combination. The non-foamed inner layer 12 may contain a thermoplastic resin other than vinyl chloride-based resin. Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, polybutene, chlorinated polyethylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, polyethylene terephthalate, ABS resin, acrylic resin, and the like. These may be used alone or in combination of two or more. In the non-foamed inner layer 12, the content of the vinyl chloride-based resin with respect to the total mass of the resin is preferably 80% by mass or more and 95% by mass or less, more preferably 85% by mass or more and 90% by mass or less.

[0013] The thickness of the non-foamed inner layer 12 is preferably 1.0 mm or more and 5.0 mm or less, more preferably 1.5 mm or more and 3.5 mm or less. By setting the thickness of the non-foamed inner layer 12 within the above numerical range, there is no risk that the drain drainage flowing inside will penetrate into the foamed layer 11, and an air-conditioning drain pipe 10 with excellent heat insulation properties can be formed. On the other hand, when the closed cell ratio of the foamed layer 11 is high, since the foamed layer 11 itself prevents the penetration of drain drainage, the thickness of the non-foamed inner layer 12 may be 0.6 mm or more and 1.5 mm or less, and the air-conditioning drain pipe 10 can be made lightweight. In addition, since the thickness of the foamed layer 11 can be increased, the air-conditioning drain pipe 10 can be made to have excellent heat insulation properties.

[0014] <The foamed layer 11> The foamed layer 11 is formed by foaming a thermoplastic resin composition for foamed layer containing a resin containing a vinyl chloride-based resin and a foaming agent. The vinyl chloride-based resin may be a homopolymer of vinyl chloride monomer (polyvinyl chloride) or a copolymer of vinyl chloride monomer and another monomer copolymerizable with the vinyl chloride monomer.

[0015] Examples of the other monomer copolymerizable with the vinyl chloride monomer include monomers such as ethylene, propylene, allyl chloride, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, vinyl acetate, maleic anhydride, acrylonitrile, and the like. These may be used alone or in combination of two or more.

[0016] Vinyl chloride resins may be used alone, or two or more types may be used in combination. The foamed layer 11 may contain thermoplastic resins other than vinyl chloride resins. Examples of such thermoplastic resins include polyethylene, polypropylene, polystyrene, polybutene, chlorinated polyethylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, polyethylene terephthalate, ABS resin, and acrylic resin. These may be used individually or in combination of two or more types. In the foamed layer 11, the content of vinyl chloride resin relative to the total mass of the resin is preferably 70% by mass or more and 80% by mass or less, and more preferably 70% by mass or more and 75% by mass or less.

[0017] The mass-average molecular weight of the vinyl chloride resin is preferably 37,500 to 70,000, and more preferably 37,500 to 44,000. The mass-average molecular weight was measured by gel permeation chromatography using polyethylene glycol as the standard substance. When the vinyl chloride resin is polyvinyl chloride, the average degree of polymerization of the polyvinyl chloride is preferably 600 to 800, and more preferably 600 to 700. The average degree of polymerization can be calculated by dividing the mass-average molecular weight by the molecular weight of chloroethylene. The vinyl chloride resin may be the same as or different from the vinyl chloride resin.

[0018] Preferably, the foamed layer 11 contains a thermoplastic resin other than vinyl chloride resin, such as acrylic acid, methacrylic acid, acrylic acid ester, or methacrylic acid ester (collectively referred to as acrylic polymer compounds). The inclusion of acrylic polymers improves the closed-cell ratio and further refines the cell diameter.

[0019] The mass-average molecular weight of the acrylic polymer compound is preferably 3 million to 6 million, and more preferably 4 million to 5 million. When the foamed layer 11 contains an acrylic polymer compound, the content of the acrylic polymer compound is preferably 10 parts by mass or more and 50 parts by mass or less, more preferably 12 parts by mass or more and 36 parts by mass or less, and even more preferably 18 parts by mass or more and 24 parts by mass or less, per 100 parts by mass of the vinyl chloride resin. The thickness of the foam layer 11 is preferably 4.0 mm or more and 10 mm or less.

[0020] Either a volatile foaming agent or a decomposing foaming agent may be used as the foaming agent. Examples of volatile foaming agents include aliphatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, ethers, and ketones. Examples of aliphatic hydrocarbons include propane, butane (n-butane, isobutane), and pentane (n-pentane, isopentane, etc.), while examples of alicyclic hydrocarbons include cyclopentane and cyclohexane. Examples of halogenated hydrocarbons include one or more halogenated hydrocarbons such as trichlorofluoromethane, trichlorotrifluoroethane, tetrafluoroethane, chlorodifluoroethane, and difluoroethane. Examples of ethers include dimethyl ether and diethyl ether, and examples of ketones include acetone and methyl ethyl ketone.

[0021] Examples of decomposition-type blowing agents include inorganic blowing agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium nitrite, azide compounds, and sodium boride, as well as organic blowing agents such as azodicarbonamide, barium azodicarboxylate, and dinitrosopentamethylenetetramine.

[0022] Alternatively, a thermally expandable capsule in which the above hydrocarbon is encapsulated within a thermoplastic resin may be used. In addition, gases such as carbon dioxide, nitrogen, and air may be used as blowing agents. These may be used individually, or two or more may be used in combination. The amount of foaming agent used is preferably 1 to 8 parts by mass, and more preferably 2 to 5 parts by mass, per 100 parts by mass of vinyl chloride resin.

[0023] The foamed layer 11 may contain known stabilizers such as lead compounds (lead-based stabilizers), CaZn compounds (CaZn-based stabilizers), and tin compounds (tin-based stabilizers). In particular, the inclusion of a stabilizer containing a tin compound makes it easier to improve the thermal stability of the resin. Mercapto-based, laurate-based, and maleate-based tin compounds are preferred.

[0024] The presence and content of these compounds can be confirmed by inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES), gas chromatography-mass spectrometry (GC-MS), etc. In the case of ICP-AES, measurement can be performed in accordance with EN ISO 17353:2004. The foamed layer 11 may contain a lubricant. The inclusion of a lubricant makes it easier to maintain slipperiness with metal surfaces and between resins. Ester-based, polyethylene-based, and polyethylene oxide-based lubricants are preferred.

[0025] [Expansion ratio] The foaming ratio of the foamed layer 11 is 3.5 times or more and 10 times or less, preferably 4.0 times or more and 8 times or less, and more preferably 4.5 times or more and 6.0 times or less. By keeping the foaming ratio within the above numerical range, high thermal insulation can be provided. Furthermore, by keeping the foaming ratio within the above numerical range, the air conditioning drain pipe 10 can be made lighter. The foaming ratio can be adjusted by the type or amount of resin, the type or amount of foaming agent, manufacturing conditions, etc.

[0026] The expansion ratio can be measured using the following method. [Method for measuring foaming ratio] A section of the air conditioning drain pipe 10 is cut out to a length of 10 mm or more in the circumferential direction and 50 mm in the axial direction. The non-foamed inner layer 12 and non-foamed outer layer 13 are milled, and only the foamed layer 11 is processed into a plate shape approximately 50 mm in length to be used as a test specimen. Four test specimens are prepared, centered around four points that are evenly divided in the inner circumferential direction. The apparent density of the test specimen is determined to three decimal places using a water displacement type specific gravity analyzer at 23°C ± 2°C in accordance with JIS K 7112:1999, and the expansion ratio is calculated using the following formula (1). m = γc / γ ... (1) [In equation (1), m is the foaming ratio, and γ is the apparent density of the foamed layer 11 (g / cm³). 3 ) and γc is the density of the foamed layer 11 when it is not foamed (g / cm³). 3 )

[0027] The closed-cell ratio of the foamed layer 11 is 45% or more, preferably 60% or more, and more preferably 80% or more. The upper limit of the closed-cell ratio is not particularly limited, and in practice it is 95% or less, but it may also be 100% or 90% or less. By keeping the closed-cell ratio within the above numerical range, it is possible to improve thermal insulation while keeping costs down, prevent water from penetrating the foam layer 11, and prevent condensation from occurring on the surface of the receiving portion 21 of the pipe joint 20. Furthermore, if the closed-cell ratio of the foam layer 11 is within the above numerical range, even if the thickness of the non-foamed outer layer 13, described later, is reduced, water is less likely to penetrate from the outside, and there is a low risk of a decrease in thermal insulation performance.

[0028] The closed-cell ratio is measured in accordance with JIS K 7138:2006. The air conditioning drain pipe 10 is cut to a length of 30 mm, then cut circumferentially to a circumference of 20 mm, and the non-foamed inner layer 12 and non-foamed outer layer 13 are removed with a cutter to prepare the test specimen. The volume of the test specimen is measured using an air-comparison hydrometer under a temperature of 23°C ± 2°C. The volume of the test specimen is measured using a water-displacement hydrometer under a temperature of 23°C ± 2°C in accordance with JIS K 7112:1999. The closed-cell ratio is calculated using the following formula (2). Cc = (Va / Vaq) × 100 ... (2) [In equation (2), Cc is the percentage of closed cells (%), and Va is the volume of air compared to the standard volume (cm³). 3 ) and Vaq is the volume (cm³) of the water displacement method. 3 ) The closed-cell ratio can be adjusted by the type or amount of resin, the type or amount of foaming agent, manufacturing conditions, etc.

[0029] [Fusion strength] The fusion strength between the foamed layer 11 and the non-foamed inner layer 12 is 1.0 MPa or higher, preferably 1.5 Pa or higher, and more preferably 2.0 MPa or higher. By keeping the fusion strength within the above range, it is possible to prevent the foamed layer 11 and the non-foamed inner layer 12 from separating.

[0030] The fusion strength can be measured by the following method. [Method for measuring fusion strength] A universal testing machine (not shown) was prepared. The universal testing machine comprises a punching jig and two compression plates. The punching jig comprises a base and a pressing part located above the base. The punching jig is sandwiched between the two compression plates. Next, a test specimen was prepared by cutting an air conditioning drain pipe 10 into a tubular shape with a width of 20 mm in the axial direction of the pipe. The test specimen had a non-foamed inner layer 12, a foamed layer 11, and a non-foamed outer layer 13. Under conditions of a temperature of 23°C ± 2°C and normal humidity (45-85%), the test specimen is set between the base and the compression section of the universal testing machine. The test specimen is compressed at a speed of 10 mm / min ± 2 mm / min in the direction of the tube axis using two compression plates. The maximum load at which the fusion surface between the non-foamed inner layer 12 and the foamed layer 11 delaminates is determined, and the fusion strength is calculated using the following formulas (3) and (4). F = W / S ... (3) S = 3.14 × d × L ···(4) [In equations (3) and (4), F is the fusion strength (MPa), W is the maximum load (N), and S is the fusion area (cm²). 2 ) where d is the average outer diameter (cm) of the non-foamed inner layer 12, and L is the length (cm) of the test specimen P. The bonding strength can be adjusted by the type or amount of resin, the type or amount of foaming agent, the manufacturing conditions, etc.

[0031] [Average bubble diameter] The average bubble diameter of the foamed layer 11 is 30 μm or more and 400 μm or less, preferably 50 μm or more and 400 μm or less, more preferably 50 μm or more and 250 μm or less, and even more preferably 60 μm or more and 200 μm or less. By keeping the average bubble diameter within the above numerical range, the thermal insulation performance can be improved and water penetration into the foam layer 11 can be prevented. Even if the bubbles are not completely closed cells (closed cell ratio of 100%) and the bubble walls are partially connected, allowing water penetration, if the average bubble diameter and the closed cell ratio are within the above numerical range, water will not penetrate deep into the interior of the foam layer 11, and thermal insulation performance will not be a problem in practical use. The average bubble diameter can be adjusted by the type or amount of resin, the type or amount of foaming agent, manufacturing conditions, etc.

[0032] The average bubble diameter can be measured using the following method. [Measurement of average bubble diameter] Following the method described in JIS K 6402, four straight lines 9 cm long (corresponding to 1,800 μm in the actual cross-section) were drawn at arbitrary positions on a circumferential cross-sectional image of the foamed layer 11 of an air conditioning drain pipe, which was taken at 50x magnification using a scanning electron microscope (SEM). The average number of bubbles crossed by each line was then calculated. The average bubble diameter was calculated by dividing the average number of bubbles crossed by 1,800 μm.

[0033] <Non-foamed outer layer 13> The non-foamed outer layer 13 contains a vinyl chloride resin. The vinyl chloride resin may be a homopolymer of vinyl chloride monomers (polyvinyl chloride), or a copolymer of a vinyl chloride monomer and another monomer copolymerizable with the vinyl chloride monomer. Other monomers copolymerizable with the vinyl chloride monomer mentioned above include, for example, ethylene, propylene, allyl chloride, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, vinyl acetate, maleic anhydride, and acrylonitrile. These may be used individually or in combination of two or more.

[0034] Vinyl chloride resins may be used alone, or two or more types may be used in combination. The non-foamed outer layer 13 may contain a thermoplastic resin other than a vinyl chloride resin. Examples of such thermoplastic resins include polyethylene, polypropylene, polystyrene, polybutene, chlorinated polyethylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, polyethylene terephthalate, ABS resin, and acrylic resin. These may be used individually or in combination of two or more types. In the non-foamed outer layer 13, the content of vinyl chloride resin relative to the total mass of the resin is preferably 80% by mass or more and 95% by mass or less, and more preferably 85% by mass or more and 90% by mass or less.

[0035] The thickness of the non-foamed outer layer 13 is preferably 0.6 mm or more and 1.5 mm or less, and more preferably 1.0 mm or more and 1.3 mm or less. By making the thickness of the non-foamed outer layer 13 equal to or greater than the lower limit, the air conditioning drain pipe 10 can be made more resistant to external impacts. By making the thickness of the non-foamed outer layer 13 equal to or less than the upper limit, the air conditioning drain pipe 10 can be made lighter. In addition, since the thickness of the foamed layer 11 can be increased, the air conditioning drain pipe 10 can be made to have excellent heat insulation properties. To increase resistance to external impacts, the thickness of the non-foamed outer layer 13 is preferably 1.0 mm or more and 5.0 mm or less, and more preferably 1.5 mm or more and 3.5 mm or less. The non-foamed outer layer 13 may contain a pigment. The inclusion of a pigment can improve the appearance.

[0036] This air conditioning drain pipe 10 is, so to speak, a multi-layered pipe in which a foamed layer 11 and a non-foamed outer layer 13 are added to a pipe material that forms a non-foamed inner layer 12, and its outer diameter is an enlargement of the nominal diameter (inner diameter) of the pipe material that forms the non-foamed inner layer 12 by a range of 1 to 3 sizes. The outer diameter of the pipe may conform to the standards of existing polyvinyl chloride pipes, etc., or it may be a unique standard for the air conditioning drain pipe 10.

[0037] In this embodiment, the outer diameter of the air conditioning drain pipe 10 is preferably, for example, 32 mm or more and 114 mm or less. The inner diameter of the air conditioning drain pipe 10 is preferably, for example, 19 mm or more and 80 mm or less. The thickness of the air conditioning drain pipe 10, in this case the combined thickness of the foamed layer 11, the non-foamed inner layer 12, and the non-foamed outer layer 13, is preferably, for example, 6 mm or more and 17 mm or less.

[0038] The Young's modulus of the air conditioning drain pipe 10 is preferably 400 MPa or more and 1500 MPa or less, more preferably 500 MPa or more and 1300 MPa or less, and even more preferably 600 MPa or more and 1000 MPa or less. By keeping the Young's modulus within the above numerical range, when the air conditioning drain pipe 10 is subjected to an external force, bending and elongation deformation can be suppressed, and the air conditioning drain pipe 10 can flexibly follow these external forces, preventing it from being destroyed.

[0039] The Young's modulus, also known as the modulus of elasticity or Young's modulus, is determined from the tensile stress and tensile strain obtained by a tensile test, according to JIS K 7161-1:2014. The Young's modulus can be adjusted by the degree of polymerization of the vinyl chloride resin, the foaming ratio of the foamed layer, and the thickness of each of the foamed layer 11, the non-foamed inner layer 12, and the non-foamed outer layer 13.

[0040] The coefficient of linear expansion of the air conditioning drain pipe 10 is 5 × 10 -5 / ℃ or higher, 7×10 -5 It is preferable that the temperature is less than / ℃. If the coefficient of linear expansion of the air conditioning drain pipe 10 is large, the expansion of the air conditioning drain pipe 10 will increase the stress on the receiving portion 21 of the pipe joint 20, which will be described later, and there is a risk that cracks may occur in the receiving portion 21.

[0041] [Air conditioning drain pipe fitting 20] As shown in Figure 2, the air conditioning drain pipe fitting 20 comprises a plurality of receiving ports 21 to which the air conditioning drain pipe 10 is connected, a fitting body 22 that connects the plurality of receiving ports 21, and a sealing member 40 positioned at the back of the plurality of receiving ports 21. The joint body 22 and the receiving portion 21 are integrally formed by injection molding of synthetic resin material. The receiving portion 21 is cylindrical. In the following description, the direction along the central axis O of the receiving portion 21 is referred to as the axial direction, and the direction perpendicular to the axial direction is referred to as the radial direction. The joint body 22 has an L-shaped elbow form. Two receiving portions 21 are connected to the joint body 22. The central axes O of the two receiving portions 21 are perpendicular to each other.

[0042] A stopper 23, consisting of a stepped portion, is formed at the back of the receiving portion 21 into which the air conditioning drain pipe 10 is inserted. The stopper 23 restricts the insertion of the air conditioning drain pipe 10 and has a restricting surface 23A facing axially. The restricting surface 23A has an annular shape coaxial with the central axis O and is formed by a flat surface perpendicular to the central axis O. The restricting surface 23A of the stopper 23 has an inner diameter (for example, the same diameter) that corresponds to the inner diameter of the air conditioning drain pipe 10. The radial thickness corresponds to the thickness of the air conditioning drain pipe 10. The inner diameter of the receiving portion 21 corresponds to the outer diameter of the air conditioning drain pipe 10 (for example, they are the same diameter). Also, the inner diameter of the air conditioning drain pipe 10 corresponds to the inner diameter of the fitting body 22 (for example, they are the same diameter).

[0043] A stepped portion 24 is formed on the outer circumference 32 of the joint body 22 at the connection point with the receiving portion 21, extending radially. The stepped portion 24 has an inclined surface 24A that gradually extends radially outward as it moves from the joint body 22 side toward the receiving portion 21 side.

[0044] The air conditioning drain pipe fitting 20 is provided with an insulating layer. The insulating layer of the air conditioning drain pipe fitting 20 may be a removable external insulation or a non-removable, integrated insulating layer. In this embodiment, as shown in Figure 2, the insulating layer 25 is integrally provided with the fitting body 22. For external insulation, insulation tubes with the required insulation thickness are wrapped on-site or pre-fabricated. Furthermore, if fittings such as sockets are configured to absorb the diagonal cut of the air conditioning drain pipe 10 and prevent gaps at the back of the socket, then an insulation layer may be omitted. In the case of a non-detachable, one-piece product, the heat insulating layer 25 may be integrally molded by injection molding or the like, or it may be formed by combining separate parts by adhesive bonding or the like. This heat insulating layer 25 may be a cavity space for air insulation, but in this embodiment, it is filled with foamed resin.

[0045] In this embodiment, the thermal insulation layer 25 is arranged over the entire length of the joint body 22 in the direction in which it extends. In other words, the thermal insulation layer 25 extends along the L-shaped flow path formed by the joint body 22 in a cross-sectional view of the joint body 22. In the illustrated example, the thermal insulation layer 25 in the joint body 22 is formed between the inner circumference 31 and the outer circumference 32 of the joint body 22. The thermal insulation layer 25 is made of foamed resin.

[0046] In this embodiment, the heat insulating layer 25 is not placed in the receiving portion 21. However, in the receiving portion 21, the heat insulating layer 25 may be placed only in the connection portion with the joint body 22. In this case, the heat insulating layer 25 in the receiving portion 21 may also be formed between the inner circumference and the outer circumference of the receiving portion 21. Furthermore, the heat insulating layer 25 in the joint body 22 and the heat insulating layer 25 in the receiving portion 21 may be integrally formed from the same heat insulating layer 25.

[0047] The portion of the fitting body 22 other than the insulation layer 25 (hereinafter referred to as the non-foamed portion) is made of a non-foamed resin. The material of the air conditioning drain pipe fitting 20 is not limited to any material that is compatible with the air conditioning drain pipe 10 using a solvent adhesive as described later. For example, non-foaming resins include polyvinyl chloride resin, ABS resin, AES resin, polyethylene resin, polypropylene resin, and acrylic resin. From the viewpoint of transparency, ABS resin and AES resin are particularly preferred. On the other hand, from the viewpoint of chemical resistance, polyvinyl chloride resin, polyethylene resin, and polypropylene resin are particularly preferred.

[0048] ABS resin and AES resin are resins obtained by polymerizing aromatic vinyl monomer and vinyl cyanide monomer in the presence of rubber components. The rubber components refer to monomer components that are raw materials for diene rubbers such as polybutadiene and polyisoprene. Examples of rubber components include butadiene, isoprene, ethylene, and propylene. Examples of aromatic vinyl monomers include styrene and α-methylstyrene. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile.

[0049] The non-foaming resin, composed of ABS resin and / or AES resin, preferably contains units derived from vinyl cyanide monomer in an amount of 10% to 50% by mass, and more preferably 15% to 45% by mass, relative to the total mass of the first resin. If the content of units derived from vinyl cyanide monomer is above the lower limit, the tensile strength can be improved. If the content of units derived from vinyl cyanide monomer is below the upper limit, the impact strength can be improved.

[0050] The rubber component content of the non-foaming resin composed of ABS resin and / or AES resin is not particularly limited, but is preferably 1% by mass or more and 20% by mass or less based on the total mass of the non-foaming resin. The non-foaming resin composed of ABS resin and / or AES resin preferably contains units derived from aromatic vinyl monomers in an amount of 15% to 60% by mass, and more preferably 20% to 50% by mass, relative to the total mass of the non-foaming resin. If the content of units derived from aromatic vinyl monomers is above the lower limit, the indentation hardness can be improved. If the content of units derived from aromatic vinyl monomers is below the upper limit, the impact strength can be improved.

[0051] The content of each component in non-foaming resins is determined by analysis using pyrolysis gas chromatography-mass spectrometry (PGC / MS). This section describes a method for calculating the content of each component in the first resin using PGC / MS measurement.

[0052] First, each component constituting the first resin is thermally decomposed and separated by pyrolysis gas chromatography to obtain a pyrolysis pattern (pyrogram) in which each component is recorded as a peak. Next, the acrylonitrile, rubber component, and styrene component are identified from each peak in the pyrolysis pattern by mass spectrometry obtained from a mass spectrometer. Here, since the acrylonitrile, rubber component, and styrene components have different depolymerization rates (the rate at which the polymer decomposes into monomers) due to thermal decomposition, the peak area (Z) of each component is calculated by dividing the peak area (X) of each component by its depolymerization rate (Y) due to thermal decomposition. The depolymerization rates (Y) of each component are acrylonitrile: 0.15, rubber component: 0.10, and styrene: 1.0.

[0053] Then, the ratio (Z / T) of the peak areas (Z) of each component in the thermal decomposition pattern to the sum (T) of the peak areas (Z) of each component is defined as the content of each component in the first resin. Furthermore, the foamed resin constituting the heat insulating layer 25 can be made of the same material as the non-foamed resin described above, and it is preferable that the heat insulating layer 25 and the non-foamed portion are made of the same resin.

[0054] The receiving portion 21 has transparency that allows the air conditioning drain pipe 10 connected to the receiving portion 21 to be visible from the outside. In this embodiment, the receiving portion 21 has transparency that allows the end of the air conditioning drain pipe 10 disposed within the receiving portion 21, the adhesive inside the receiving portion 21, and the sealing member 40 including the solvent-bondable resin layer 42 after bonding to be visible from the outside.

[0055] [Sealing member 40] The sealing member 40 is an annular disc formed by laminating two or more layers, including a compressible elastic layer 41 and a flexible solvent-adhesive resin layer 42. The sealing member 40 has an inner diameter corresponding to the inner diameter of the air conditioning drain pipe 10 and an outer diameter corresponding to the inner diameter of the back of the receiving opening 21. The sealing member 40 is positioned at the back of each receiving portion 21 of the air conditioning drain pipe fitting 20. The sealing member 40 is positioned in contact with the regulating surface 23A on the air conditioning drain pipe 10 side of the stopper 23.

[0056] The compressible elastic layer 41 may be made of a non-polar material that cannot be solvent-bonded to PVC-based materials, such as foamed polyethylene or foamed cross-linked polyethylene. There are no particular restrictions on the compressibility and thickness of the elastic layer 41, but it is preferable that the elastic layer 41 can elastically deform under compression to follow any diagonal cuts of 2 mm or more formed at the end of the air conditioning drain pipe 10 when the air conditioning drain pipe 10 is pressed vertically (axially) with a force of 200 N.

[0057] There are no particular restrictions on the repulsive force of the elastic layer 41, but it is preferable that the elastic layer 41 elastically deforms to follow a diagonal cut of 2 mm or more formed at the end of the air conditioning drain pipe 10 when the air conditioning drain pipe 10 is pressed vertically (axially) with a force of 200 N. It is undesirable if the elastic layer 41 collapses over a wide area when pressed by a pointed tip formed at the end of the air conditioning drain pipe 10, thereby forming a gap between the sealing member 40 and the end of the air conditioning drain pipe 10.

[0058] In other words, the elastic layer 41 acts as a backup material to prevent a gap from forming between the sealing member 40 and the end of the air conditioning drain pipe 10 when an uneven shape, such as a diagonal cut, is formed at the end of the air conditioning drain pipe 10. For this reason, it is preferable to select the thickness of the elastic layer 41 according to the characteristics of the material used. For example, when using a material with a compressibility of 30 to 70% at 200N, it is more preferable for the thickness to be 3 mm or more and less than 10 mm.

[0059] The flexible solvent-adhesive resin layer 42 is positioned to face the end of the air conditioning drain pipe 10, which is inserted into the receiving portion 21 of the air conditioning drain pipe fitting 20, and is a layer that is bonded to the end surface. The solvent-bondable resin layer 42 is required to be able to be joined by closely adhering to the end face of the air conditioning drain pipe 10 to which the solvent adhesive has been applied. On the other hand, flexibility is required for the solvent-adhesive resin layer 42. The end face of the air conditioning drain pipe 10, which has been cut with a handsaw or the like, may be curved. Therefore, when the air conditioning drain pipe 10 is inserted into the receiving portion 21 during solvent bonding, the solvent-adhesive resin layer 42 must deform flexibly along with the compression of the elastic layer 41 and adhere closely to the end face of the air conditioning drain pipe 10.

[0060] The material of the solvent-bondable resin layer 42 can be any material that is compatible with and can be bonded to the air conditioning drain pipe 10 using a solvent adhesive. For example, even if the air conditioning drain pipe 10 is made of polyvinyl chloride, the material is not limited to polyvinyl chloride; any material compatible with polyvinyl chloride, such as ABS resin, AES resin, or acrylic resin, is acceptable. The thickness of the solvent-adhesive resin layer 42 is preferably 3 mm or less. If it is excessively thick, the solvent-adhesive resin layer 42 will have difficulty conforming to the shape of the end of the air conditioning drain pipe 10.

[0061] The sealing member 40, in particular the solvent-adhesive resin layer 42, should preferably exhibit a color different from that of the end of the air conditioning drain pipe 10, the receiving portion 21, and the solvent adhesive inside the receiving portion 21.

[0062] These sealing members 40 may be fixed to the back of the receiving portion 21 of the air conditioning drain pipe fitting 20 using an adhesive or glue. By using an adhesive or glue, displacement of the solvent-bondable resin layer 42 can be prevented. Therefore, for example, when the end of the air conditioning drain pipe 10 is pressed with a pointed end such as an oblique cut, the solvent-bondable resin layer 42 can be prevented from shifting or tilting. As a result, even if, for example, the end of the air conditioning drain pipe 10 is only shallowly inserted into the receiving port 21, the solvent-adhesive resin layer 42 is perceived as being in contact with the end of the air conditioning drain pipe 10 in a compressed state, thereby reducing the risk of overlooking insufficient insertion.

[0063] When using an adhesive, the sealing member 40 may have a four-layer structure, for example, consisting of a solvent-adhesive resin layer 42, a double-sided tape layer, a compressible elastic layer 41, and another double-sided tape layer. The four-layer sealing member 40 is installed at the back of the receiving end 21 before connecting the air conditioning drain pipe 10 to the air conditioning drain pipe fitting 20. Preferably, it is installed at the back of the fitting at the factory shipping stage. Furthermore, in order to prevent misalignment between layers in the one-piece multi-layer structure, it is preferable to manufacture the one-piece sealing member 40 by laminating raw material sheets together and then punching them out.

[0064] In this embodiment, a sealing member 40 is placed at the back of the receiving portion 21 of the air conditioning drain pipe fitting 20, and a solvent adhesive is used to insert the end of the air conditioning drain pipe 10 into this receiving portion 21 and join them. During adhesive joining, the solvent adhesive is applied to the inner surface of the receiving portion 21 of the air conditioning drain pipe fitting 20, the surface of the sealing member 40, and the outer surface and end face of the end of the air conditioning drain pipe 10, and solvent joining is performed. There are no particular restrictions on the solvent adhesive used; any commercially available organic solvent product that can be used for solvent bonding of polyvinyl chloride pipes is acceptable.

[0065] The solvent adhesive may be colored to prevent it from being missed during application, and may also contain a fluorescent agent that fluoresces when exposed to ultraviolet light. Furthermore, the air conditioning drain pipe fitting 20 should preferably have transparency that allows for checking for uneven application of the solvent adhesive, and it is preferable to use it in combination with colored solvent adhesives. Furthermore, it is preferable that at least the solvent-adhesive resin layer 42 of the sealing member 40 exhibits a distinctly different color from the air conditioning drain pipe 10, the air conditioning drain pipe fitting 20, or the adhesive. For example, if the air conditioning drain pipe fitting 20 and the air conditioning drain pipe 10 are ivory in color, and the colored adhesive is blue, it is preferable that the sealing member 40 be a different color, such as red.

[0066] The air conditioning drain pipe fitting 20 described above provides the following effects and benefits. First, even if the end face of the air conditioning drain pipe 10 is inclined with respect to the axial direction or has an uneven shape, the elastic layer 41 is compressed in accordance with the shape of the end face of the air conditioning drain pipe 10, thereby applying the elastic force of the elastic layer 41 to the entire circumference of the end face of the air conditioning drain pipe 10. As a result, the solvent-adhesive resin layer 42 on the surface positioned on the air conditioning drain pipe 10 side of the elastic layer 41 can be made to adhere tightly to the entire circumference of the end face of the air conditioning drain pipe 10. This makes it easier to seal the entire circumference of the end of the foam layer 11 of the air conditioning drain pipe 10 and to highly prevent water from penetrating into the foam layer 11.

[0067] Generally, the air conditioning drain pipe 10 is cut to any desired length at the construction site and connected by inserting the end of the air conditioning drain pipe 10 into the receiving portion 21 of the air conditioning drain pipe fitting 20. Therefore, inside the receiving portion 21 of the air conditioning drain pipe fitting 20, the non-foamed inner layer 12, the foamed layer 11, etc., are exposed at the end face (cut surface) of the air conditioning drain pipe 10. In the air conditioning drain pipe 10, unless the foam layer 11 is completely independently foamed, drain water flowing down the inside of the pipe will relatively permeate it. For this reason, conventional methods have included uniformly applying a solvent adhesive to the end of the air conditioning drain pipe 10 or providing an annular elastic body inside the air conditioning drain pipe fitting 20.

[0068] In recent years, the environment surrounding air conditioning has changed due to the COVID-19 pandemic. Ventilation, which reduces air conditioning efficiency, has become more active, and outside humidity is constantly supplied to the indoors. As a result, the air conditioning drain pipe 10 is required to have improved condensation prevention performance more than ever before. In order to improve performance, it is necessary to further enhance the ability to prevent water penetration from the ends of the air conditioning drain pipe 10, taking into account variations in on-site construction. The same applies even if the thickness of the foam layer 11 is increased to improve performance. In light of this situation, the inventors of the present invention conducted research to further suppress water penetration into the foam layer 11.

[0069] The end face of the air conditioning drain pipe 10 has the foam layer 11 exposed with the surface bubbles broken, which can lead to water penetration. Since penetration reduces insulation performance, countermeasures are necessary. Previously, this water penetration was prevented by evenly applying adhesive to the end face of the air conditioning drain pipe 10. However, because the end face of the foam layer 11 formed by cutting the air conditioning drain pipe 10 at the construction site has irregularities, even if the worker carefully applies the adhesive, missed spots can occur. Therefore, areas where the adhesive is not applied can occur.

[0070] Some products incorporate an elastic material deep inside the air conditioning drain pipe fitting 20. This material was intended to fill gaps in the foam layer 11 caused by diagonal cuts during the cutting of the air conditioning drain pipe 10. Furthermore, because it is made of non-polar resin such as foamed polyethylene, solvent adhesives are incompatible with the air conditioning drain pipe 10. Therefore, even with the use of an elastic material, its function of compensating for uncoated areas was insufficient. Regarding elastic materials, for example, Patent Document 2 mentioned above stated that using them in combination with sealants is also effective. Using sealants to prevent rust at the ends of air conditioning drain pipes 10 is a standard practice in flexible joints for drainage steel pipes (MD joints: watertightened by tightening a rubber ring), but it has been difficult to adopt in adhesive bonding due to the risk of sealant adhering to the bonding surface.

[0071] Furthermore, Patent Document 2 suggests using water-swellable rubber for the elastic body, but this is practically difficult. The reasons for this include the difficulty in ensuring that the material does not get wet until immediately before construction under current operating conditions, the difficulty in establishing conditions that effectively seal the gaps in the diagonal cuts with water when expanded, and the difficulty in taking measures to prevent water from forming if cutting burrs remain, even if the compression is appropriate.

[0072] The inventors of this invention researched methods to further reduce the risk of uneven coating, based on current waterproofing measures. They concluded that the main cause of uneven coating is the fine irregularities on the foamed surface at the end of the pipe. One way to reduce missed spots due to the fine irregularities on the foamed surface at the end of the pipe is to first lower the viscosity of the adhesive to make it easier to spread. However, even if a separate adhesive for pipe end application were prepared, the likelihood of its adoption is low due to fears of misuse. Therefore, it is essential that the adhesive remains the same as before, without any distinction in application.

[0073] Similarly, applying silicone sealant to the pipe ends beforehand and waiting for it to dry before starting work was far removed from the reality of the site. Therefore, the additional work required had to be completely eliminated, or at least without any waiting time.

[0074] Furthermore, to confirm the adhesive performance, an evaluation was conducted by applying adhesive to the end face of a commercially available 0.5 mm thick PVC sheet for crafting purposes and an air conditioning drain pipe 10 with a nominal diameter of 25 mm (manufactured by Sekisui Chemical Co., Ltd., product name "Eslon AC Drain Fitting") and pressing them together. As a result, it was confirmed that the non-foamed inner layer 12 and the non-foamed outer layer 13 adhered better than the foamed layer 11. Regarding the non-foamed outer layer 13, it was concluded that the non-foamed outer layer 13 is not essential for the outer periphery, as the adhesive applied to the receiving portion 21 is scraped off and the adhesive accumulates and fills the area. However, in this evaluation, the cut surface was slightly wavy because it was cut with a handsaw, and the worker pressed it down by hand to seal it. It would have been preferable to select a sealing method that would allow for some wavyness in the cut surface.

[0075] From the above verification, the inventors of the present invention have found that by placing an annular disc-shaped sealing member that covers the end of the air conditioning drain pipe 10 at the back of the receiving portion 21 of the air conditioning drain pipe fitting 20, and by arranging an elastic layer and a solvent-adhesive resin layer, water penetration into the end face of the air conditioning drain pipe after adhesive bonding can be effectively prevented.

[0076] Furthermore, in the air conditioning drain pipe fitting 20 of this embodiment, the sealing member 40 is a disc shape having a predetermined inner and outer diameter. Therefore, the entire sealing member 40 can be reliably positioned in the stopper 23 at the back of the receiving portion 21, and the surface of the sealing member 40 can face the entire end face of the air conditioning drain pipe 10. Moreover, since it has a compressible elastic layer 41 and a flexible solvent-adhesive resin layer 42, the solvent-adhesive resin layer 42 can adhere uniformly and reliably to the entire end face of the air conditioning drain pipe 10 due to the elasticity of the elastic layer 41. Therefore, the effect of preventing water penetration from the end of the foam layer 11 can be improved.

[0077] Furthermore, in the air conditioning drain pipe fitting 20 of this embodiment, the solvent-adhesive resin layer 42 facing the end of the air conditioning drain pipe 10 exhibits a different color from the air conditioning drain pipe 10, the receiving portion 21, and the adhesive. Therefore, when the end of the air conditioning drain pipe 10 is inserted into the receiving portion 21 and bonded, and the sealing member 40 is visually inspected, the solvent-adhesive resin layer 42 is less likely to be mistaken for the air conditioning drain pipe 10, the receiving portion 21, and the adhesive. This makes it easier to confirm the arrangement of the sealing member 40 and the solvent-adhesive resin layer 42, and ensures that the solvent-adhesive resin layer 42 is securely bonded to the end of the foam layer 11.

[0078] Furthermore, in the air conditioning drain pipe fitting 20 of this embodiment, the receiving portion 21 is transparent, allowing the solvent-adhesive resin layer 42 to be visually inspected from the outside after bonding. Therefore, it is easy to confirm after bonding whether the solvent-adhesive resin layer 42 has covered and bonded the end of the foam layer 11 of the air conditioning drain pipe 10. This ensures that the solvent-adhesive resin layer 42 is securely sealed and bonded to the end of the foam layer 11 of the air conditioning drain pipe 10, preventing bonding errors.

[0079] Next, a modified example of the air conditioning drain pipe fitting 20 of this embodiment will be described. In the above embodiment, an example was described in which the shape of the fitting body 22 in the air conditioning drain pipe fitting 20 is elbow-shaped, but the shape of the air conditioning drain pipe fitting 20 is not limited to elbow shape. For example, the fitting body 22D may have a socket shape, as shown in the first modified example of the air conditioning drain pipe fitting 20D in Figure 4. This air conditioning drain pipe fitting 20D comprises a straight cylindrical fitting body 22D and two coaxially arranged receiving portions 21. Even with an air conditioning drain pipe fitting 20 of this socket shape, the same effects and advantages as in the above embodiment can be achieved.

[0080] Furthermore, the fitting body 22C may have a tee shape, as in the air conditioning drain pipe fitting 20C shown in the second modified example in Figure 5. This air conditioning drain pipe fitting 20C comprises a T-shaped fitting body 22C and three receiving portions 21. Even with an air conditioning drain pipe fitting 20 of this socket shape, the same effects and advantages as in the above embodiment can be achieved.

[0081] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and modifications, combinations, deletions, etc., of the configuration are also included without departing from the spirit of the present invention.

[0082] For example, in the above embodiment, an example was described in which the air conditioning drain pipe fitting 20 is transparent, but it is not necessarily required to be transparent, and the present invention can be applied even if it is opaque due to being colored with pigment. Furthermore, for example, cuts may be made in the solvent-adhesive resin layer 42. In this case, the cuts may be made in the direction of the shortest distance between the outer and inner circumference, diagonally, or in a spiral pattern. The cut surfaces may overlap with the cuts. In addition, multiple cuts (slits) or multiple cuts may be made. [Examples]

[0083] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited in any way by these examples.

[0084] (Example 1) For the air conditioning drain pipe 10, a nominal diameter of 25 of the "Eslon AC Drain Pipe" (product name) manufactured by Sekisui Chemical Co., Ltd. was used. First, the original air conditioning drain pipe 10 was cut at an angle of 2 mm and chamfered. This reproduces the angled cut that can occur even when one intends to cut straight.

[0085] Next, as the solvent-bondable resin layer 42, an annular disc with an inner diameter of 25.0 mm and an outer diameter of 37.6 mm was cut from a 0.5 mm thick polyvinyl chloride plastic board. These dimensions are the inner diameter of the air conditioning drain pipe 10 and the outer diameter of the innermost part of the receiving port 21 of the air conditioning drain pipe fitting 20, which will be described later.

[0086] The air conditioning drain pipe fitting 20 uses a socket with a nominal diameter of 25, manufactured by Sekisui Chemical Co., Ltd. as part of their "Eslon AC Drain Pipe Fitting" (product name). This air conditioning drain pipe fitting 20 has a stopper 23 at the back of the receiving portion 21 that restricts insertion, and this stopper 23 has a hole with an inner diameter of 25 mm. This hole has the same diameter as the inner diameter of the air conditioning drain pipe 10. A 5mm thick elastic layer 41 is fixed to the air conditioning drain pipe fitting 20 at the back of the receiving portion 21 of the air conditioning drain pipe fitting 20 using adhesive tape. An annular disc of solvent-adhesive resin layer 42 is further fixed to the back of the receiving portion 21 of the air conditioning drain pipe fitting 20 using adhesive tape on top of this elastic layer 41.

[0087] The air conditioning drain pipe 10 and sealing member 40 prepared as described above were bonded and fixed to the receiving portion 21 of the air conditioning drain pipe fitting 20 using a solvent adhesive, and the fitting insertion evaluation was performed. As a solvent adhesive, "No. 75S" (product name) manufactured by Sekisui Chemical Co., Ltd. was used and uniformly applied to the inner surface of the receiving portion 21 of the air conditioning drain pipe fitting 20 and to the outer surface and end surface of the end of the air conditioning drain pipe 10. The solvent adhesive was also applied to the surface of the sealing member 40.

[0088] After the above joint insertion evaluation, the socket was sliced ​​crosswise along the elastic surface to evaluate the adhesion state. As a result, the elastic layer 41 of the sealing member 40 was elastically deformed and compressed in response to the diagonal cuts and irregularities formed at the end of the air conditioning drain pipe 10. This caused the solvent-adhesive resin layer 42 to deform in accordance with the inclination of the diagonal cuts and irregularities, resulting in the solvent-adhesive resin layer 42 being tightly adhered to the entire end surface of the air conditioning drain pipe 10. From these results, it could be inferred that the sealing member 40 complements the conventional adhesive application to the end face and can more effectively prevent water from penetrating into the foam layer 11 of the air conditioning drain pipe 10 than before.

[0089] (Example 2) Next, the bonding state was evaluated in the same manner as in Example 1, except that a sealing member 40 was used, which had a single cut made in the solvent-adhesive resin layer 42 from the outer circumference to the inner circumference. As a result, similar to Example 1, the elastic layer 41 of the sealing member 40 was compressed in response to the irregularities of the diagonal cut at the end of the air conditioning drain pipe 10, causing the solvent-adhesive resin layer 42 to deform in accordance with the inclination of the irregularities of the diagonal cut, and the solvent-adhesive resin layer 42 was tightly bonded to the entire end surface of the air conditioning drain pipe 10.

[0090] (Note) The above embodiment can be understood, for example, as follows:

[0091] <1> An air conditioning pipe joint according to one aspect of the present invention is a joint for an air conditioning pipe that is a multi-layer pipe of two or more layers, comprising a cylindrical foamed layer and a non-foamed inner layer provided on the inner surface of the cylindrical foamed layer, wherein a stopper is provided at the back of the receiving portion into which the air conditioning pipe is inserted to restrict the insertion of the air conditioning pipe, and a sealing member composed of two or more layers including an elastic layer is provided on the restricting surface of the stopper on the air conditioning pipe side.

[0092] With this type of air conditioning pipe fitting, even if the end face of the air conditioning pipe is inclined with respect to the axial direction or has an uneven shape, the elastic layer is compressed in accordance with the shape of the end face of the air conditioning pipe, thereby applying the elastic force of the elastic layer to the entire circumference of the end face of the air conditioning pipe. As a result, the surface of the layer positioned on the air conditioning pipe side of the elastic layer can be brought into close contact with the entire circumference of the end face of the air conditioning pipe. This makes it easier to seal the entire circumference of the end of the foamed layer of the air conditioning pipe, thereby highly preventing water from penetrating into the foamed layer. As a result, it is possible to provide an air conditioning pipe fitting that can highly prevent water from penetrating from the end of the foamed layer.

[0093] <2> the above <1> In the air conditioning pipe fittings relating to the above, the sealing member may include a compressible elastic layer having a thickness of 3 mm or more and less than 10 mm, and a solvent-adhesive resin layer having a thickness of 3 mm or less and being flexible.

[0094] This air conditioning pipe fitting has a compressible elastic layer and a flexible solvent-adhesive resin layer. The solvent-adhesive resin layer adheres uniformly and reliably to the entire end face of the air conditioning pipe due to the elasticity of the elastic layer. Therefore, the effect of preventing water penetration from the end of the foam layer is improved.

[0095] <3> the above <2> In the air conditioning pipe fitting relating to the present invention, the solvent-adhesive resin layer is arranged to face the end of the air conditioning pipe inserted into the socket portion, and may exhibit a different color from the air conditioning pipe, the socket portion, and the adhesive inside the socket portion.

[0096] In this air conditioning pipe fitting, the solvent-adhesive resin layer facing the end of the air conditioning pipe exhibits a different color from the air conditioning pipe, the socket, and the adhesive. Therefore, when the end of the air conditioning pipe is inserted into the socket and bonded, and the sealing member is visually inspected, the solvent-adhesive resin layer is less likely to be mistaken for the air conditioning pipe, the socket, or the adhesive. This makes it easier to confirm the arrangement of the sealing member and the solvent-adhesive resin layer, and ensures that the solvent-adhesive resin layer is securely bonded to the end of the foam layer.

[0097] <4> the above <3> In the air conditioning pipe fitting relating to the present invention, the receiving portion may have transparency that allows the inserted air conditioning pipe to be visually inspected from the outside, and the solvent-bondable resin layer arranged inside the receiving portion after bonding may also be visually inspected from the outside.

[0098] In this air conditioning pipe fitting, the socket portion is transparent, allowing the solvent-bondable resin layer to be visually inspected from the outside after bonding. Therefore, it is easy to confirm after bonding whether the solvent-bondable resin layer has properly covered and bonded the end of the foamed layer of the air conditioning pipe. This ensures that the solvent-bondable resin layer is securely sealed and bonded to the end of the foamed layer of the air conditioning pipe, preventing bonding errors. [Explanation of Symbols]

[0099] 1. Joint structure 10. Air conditioning drain pipe (air conditioning pipe) 11 Foam layer 12 Non-foamed inner layer 13 Non-foamed outer layer 20. Air conditioning drain pipe fittings (air conditioning pipe fittings) 21 Receiving opening 22 Fitting body 23 Stopper 23A Regulatory aspects 24 Step section 25. Insulation layer 31 Inner circumference 32 Outer periphery 40 sealing member 41 Elastic layer 42 Solvent-bondable resin layer

Claims

1. A joint for an air conditioning pipe that is a multi-layered pipe with two or more layers, comprising a cylindrical foamed layer and a non-foamed inner layer provided on the inner surface of the cylindrical foamed layer, A stopper is provided at the back of the receiving portion into which the air conditioning pipe is inserted, to restrict the insertion of the air conditioning pipe. An air conditioning pipe joint characterized in that a sealing member composed of two or more layers, including an elastic layer, is provided on the regulating surface of the stopper on the air conditioning pipe side.

2. The sealing member is A compressible elastic layer with a thickness of 3 mm or more and less than 10 mm, The air conditioning pipe fitting according to claim 1, characterized by comprising a solvent-adhesive resin layer having a thickness of 3 mm or less and being flexible.

3. The air conditioning pipe fitting according to claim 2, characterized in that the solvent-adhesive resin layer is arranged to face the end of the air conditioning pipe inserted into the receiving portion, and exhibits a color different from that of the air conditioning pipe, the receiving portion, and the adhesive inside the receiving portion.

4. The air conditioning pipe fitting according to claim 3, characterized in that the receiving portion has transparency that allows the inserted air conditioning pipe to be visually inspected from the outside, and the solvent-bondable resin layer arranged inside the receiving portion after bonding can be visually inspected from the outside.

Images