Air conditioning system pipeline

Abstract

A pipeline for an air conditioning system, comprising: a first pipe fitting (100) and a second pipe fitting (200), the second pipe fitting (200) being of a separate structure and including multiple stages of pipe bodies, the multiple stages of pipe bodies being arranged as a first pipe body (210) and at least one stage of a second pipe body (220), the first pipe body (210) and the first pipe fitting (100) being connected by furnace welding, and the second pipe body (220) and one end of the first pipe body (210) remote from the first pipe fitting (100) being connected by welding.

Description

[Technical field]

[0001] Related Applications This application claims priority to a Chinese patent application filed on January 20, 2022, bearing application number 202220158839.8 and entitled "Pipeline for Air Conditioning System", and to a Chinese patent application filed on January 20, 2022, bearing application number 202210065987.X and entitled "Pipeline for Air Conditioning System", the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of air conditioning systems, and in particular to pipelines for air conditioning systems. [Background technology]

[0003] In the air conditioning system of the related art, the communication of each pipeline element is realized by the air conditioning pipeline, and the air conditioning pipeline mainly includes a pipeline body and other branch pipes connecting the air conditioning elements, but the pipeline body has a large volume and the branch pipes have a relatively complicated shape, so the overall volume of the air conditioning pipeline is very large, making it difficult to assemble the pipeline body and the branch pipes, resulting in low assembly efficiency and difficulty in realizing automation. In addition, the pipeline body occupies a large space, making it difficult to realize in-furnace welding, resulting in low welding efficiency and poor welding effect. Summary of the Invention

[0004] Various embodiments of the present application provide a pipeline for an air conditioning system with better assembly and welding effects.

[0005] The pipeline for an air conditioning system includes a first pipe joint and a second pipe joint, the second pipe joint being a separate structure and including multiple stages of pipe bodies, the multiple stages of pipe bodies being arranged as a first pipe body and at least one stage of a second pipe body, where one end of the first pipe body and the first pipe joint are connected by furnace welding, and the other end of the first pipe body remote from the first pipe joint and the second pipe body are connected by welding.

[0006] In one embodiment, the first pipe fitting and the first tube are welded by solder. In one embodiment, the first tube and the second tube are welded by autogenous welding or solder. Two adjacent second tubes are welded by autogenous welding or solder.

[0007] In one embodiment, the first and second tubes are connected using a bayonet method and then welded.

[0008] In one embodiment, one of the first tube and the second tube is provided with an insertion portion, and the other is provided with a socket portion, and the insertion portion is inserted into the socket portion and welded to it.

[0009] In one embodiment, a limiting structure is provided between the insertion portion and the socket portion to limit the insertion length between the first tube and the second tube.

[0010] In one embodiment, the first tube and the second tube on which the insertion portion is provided further includes a first main body portion and a first connecting portion, the first main body portion is connected to the insertion portion via the first connecting portion, and a diameter of the insertion portion is smaller than a diameter of the first body portion, and when the insertion portion is inserted into the socket portion, the first connecting portion stops the socket portion to form a restricting structure.

[0011] In one embodiment, the first tube and the second tube, whichever has the socket portion, further includes a second main body portion and a second connecting portion, the second main body portion is connected to the socket portion via the second connecting portion, and the diameter of the socket portion is larger than the diameter of the second main body portion, and when the insertion portion is inserted into the socket portion, the second connecting portion stops the insertion portion to form a restricting structure.

[0012] In one embodiment, the central axis of the welding torch nozzle is defined as l, the central axis of the socket portion is defined as b, and the included angle between the central axis l and the central axis b of the socket portion is defined as α, where α must satisfy the relational expression 10°≦α≦60°.

[0013] In one embodiment, the heat distribution ratio when the insertion portion and the socket portion are welded is 5:5 to 6:4.

[0014] In one embodiment, the first tube and the second tube on which the insertion portion is provided further includes a first main body portion, and a first limiting protrusion is provided between the first main body portion and the insertion portion, and the first limiting protrusion protrudes outward in the radial direction of the first main body portion to stop the socket portion and form a limiting structure.

[0015] In one embodiment, the first tube and the second tube on which the socket portion is provided further includes a second main body portion, and a second limiting protrusion is provided between the second main body portion and the socket portion, the second limiting protrusion protruding inward along the radial direction of the second main body portion, and the second limiting protrusion stops the insertion portion to form a limiting structure.

[0016] In one embodiment, when the diameter of the second pipe fitting is defined as d, d satisfies the relational expression of d≦30mm; when the weld bead gap between the first pipe body and the second pipe body is defined as δ, δ satisfies the relational expression of δ≦0.05mm; when the thickness of the second pipe fitting is defined as t, t satisfies the relational expression of t≦1.5mm; after the first pipe body and the second pipe body are connected by a plug-in method, the deviation value of the concentricity between the first pipe body and the second pipe body is not more than 0.15mm; and after the first pipe body and the second pipe body are welded, the reduction amount of the wall thickness t of the second pipe fitting is not more than 1%.

[0017] In one embodiment, the first and second tubes are butt joined and then welded.

[0018] In one embodiment, the first pipe fitting comprises a copper, steel or aluminum pipe.In one embodiment, the second pipe fitting comprises a copper, steel or aluminum pipe.

[0019] In one embodiment, the first and second tubes are butt-connected and then welded, or bayonet-connected and then welded. In one embodiment, two adjacent second tubes are butt-connected and then welded, or bayonet-connected and then welded.

[0020] The details of one or more embodiments of the application are set forth in the drawings and description below. Other features, objects, and advantages of the application will become apparent from the description, drawings, and claims. [Brief description of the drawings]

[0021] To better describe and explain the embodiments and / or examples of the inventions disclosed herein, reference may be made to one or more drawings, in which additional details or examples used to explain the drawings should not be considered as limiting the scope of any of the disclosed inventions, the embodiments and / or examples described herein, and the best mode of these inventions as understood herein.

[0022] [Figure 1] FIG. 2 is a partial cross-sectional structural schematic diagram of a pipeline for an air conditioning system provided by the present application; [Diagram 2] FIG. 2 is a partial cross-sectional exploded schematic diagram of a pipeline for an air conditioning system provided by the present application. [Diagram 3] FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application. [Figure 4] FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application. [Diagram 5] FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application. [Figure 6] FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application. [Figure 7] FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application. [Figure 8] FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application. [Figure 9] FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application. [Figure 10] 10 is a partial enlarged schematic view of part A in FIG. 9. FIG. [Figure 11]FIG. 2 is a schematic diagram illustrating an assembly of a first tube and a second tube in one embodiment of the present application.

[0023] 100 first pipe fitting, 200 second pipe fitting, 210 first tube body, 211 first main body portion, 212 insertion portion, 213 first connection portion, 214 first limiting protrusion, 220 second tube body, 221 second main body portion, 222 socket portion, 223 second connection portion, 224 second limiting protrusion, l central axis of welding torch nozzle, b central axis of socket portion, d diameter of second pipe fitting, δ weld bead gap of second tube body, t wall thickness of second pipe fitting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In order to make the above objects, features and advantages of the present application clearer and easier to understand, the following describes in detail the specific embodiments of the present application with reference to the drawings. In the following description, various specific details are described in order to facilitate a full understanding of the present application. However, the present application can be implemented in many other aspects different from those described herein, and those skilled in the art can make similar improvements without going against the content of the present application, so the present application is not limited by the specific examples disclosed below.

[0025] It should be explained that when an assembly is referred to as being "fixed" or "mounted" on another assembly, it may be directly fixed to the other assembly or there may be an intervening assembly present. When an assembly is referred to as being "connected" to another assembly, it may be directly connected to the other assembly or there may be an intervening assembly present at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for descriptive purposes only and do not represent the only embodiments.

[0026] Furthermore, the terms "first" and "second" are for descriptive purposes only and should not be understood as indicating or implying a relative importance or implicitly designating the number of technical features depicted. Thus, a feature qualified with "first" or "second" may explicitly state or implicitly include at least one of that feature. In the description of this application, "plurality" means at least two, e.g., two, three, etc., unless explicitly and specifically limited.

[0027] In this application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first feature and the second feature are in direct contact with each other, or that the first feature and the second feature are in indirect contact with each other via an intermediate medium. Furthermore, a first feature being "above," "above," and "upper side" of a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply that the horizontal height of the first feature is higher than that of the second feature. A first feature being "below," "below," and "lower side" of a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply that the horizontal height of the first feature is lower than that of the second feature.

[0028] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as commonly understood by those skilled in the art of this application. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit the application. The term "and / or" used in the specification of this application includes one or more of any and all combinations of the associated listed items.

[0029] The pipeline for an air-conditioning system of the present application will be described in more detail below with reference to the drawings and specific embodiments.

[0030] The pipeline for the air conditioning system is used in the air conditioning system to realize the communication between each air conditioning element, and the pipeline usually includes a pipeline body and a branch line, and the branch line is pre-branched from the pipeline body to connect to the air conditioning element. In the conventional pipeline processing, the whole volume is usually used in furnace welding, but the pipeline body has a large volume and the branch pipe has a relatively complicated shape, so the whole volume of the air conditioning pipeline is very large, the assembly of the pipeline body and the branch pipe is difficult, the occupied space is large, and the in-furnace welding is difficult to realize, and the welding effect is poor.

[0031] In order to overcome the problems in the prior art, referring to Figures 1 and 2, according to one embodiment of the present application, a pipeline includes a first pipe joint 100 and a second pipe joint 200, the second pipe joint 200 forms a pipeline body, and the first pipe joint 100 forms a branch line connected to an air-conditioning element. The second pipe joint 200 is a separate structure and includes multiple stages of pipe bodies, the multiple stages of pipe bodies are arranged as a first pipe body 210 and at least one stage of a second pipe body 220, the first pipe body 210 and the first pipe joint 100 are connected by furnace welding, and the second pipe body 220 and one end of the first pipe body 210 remote from the first pipe joint 100 are connected by welding.

[0032] In this embodiment, after the second pipe joint 200 is divided into the first pipe body 210 and at least one stage of the second pipe body 220, the length and volume of each pipe body are both small, and it is only necessary that the first pipe body 210 and the first pipe joint 100 are welded in a furnace, and the other pipe bodies do not need to be welded in a furnace. Since the first pipe body 210 and the first pipe joint 100 have a small volume and occupy a small space after being connected, the welding in a furnace can be easily realized, the welding efficiency is improved, and the welding effect is improved.

[0033] In this embodiment, the pipeline is divided and welded separately, and then the entire pipeline is welded together, so that it is easier to realize automation of installation. At the same time, after being divided, the lengths of the first pipe joint 100, the first tube body 210, and the second tube body 220 are all shortened, so that adjacent pipe joints or tube bodies can be easily assembled with each other, and the concentricity after assembly is also higher, so that the assembly efficiency and the assembly effect are improved.

[0034] The first pipe fitting 100 and the second pipe fitting 200 are typically made of metal pipes, and the first pipe fitting 100 may be a copper pipe, a steel pipe, or an aluminum pipe, and the second pipe fitting 200 may also be a copper pipe, a steel pipe, or an aluminum pipe. In some embodiments, the first pipe fitting 100 is a copper pipe. In some embodiments, the first pipe fitting 100 is made of phosphorus deoxidized copper pipe (TP2) or pure copper pipe (T2). In some embodiments, the second pipe fitting 200 is a steel pipe. In some embodiments, the second pipe fitting 200 is made of stainless steel pipe or carbon steel pipe. In some embodiments, the second pipe fitting 200 is made of stainless steel pipe, and typically made of stainless steel materials such as SUS304, SUS304L, SUS430L, SUS316, and SUS316L.

[0035] The first pipe joint 100 and the first tube 210, the first tube 210 and the second tube 220, and two adjacent second tubes 220 are connected and assembled, and then welded.

[0036] The connection manner of the first pipe joint 100 and the first tube 210, the first tube 210 and the second tube 220, and the two adjacent second tubes 220 may be a butt connection or a plug connection, and in some embodiments, the above connection manner is a plug connection. The welding manner is autogenous welding or solder welding, such as argon arc welding, laser welding, gas shielded arc welding, flame brazing, high frequency welding, etc. In some embodiments, the first pipe joint 100 and the first tube 210 are solder welded. In some embodiments, the first tube 210 and the second tube 220, and the two adjacent second tubes 220 are autogenous welded. That is, the assembly form of the first tube 210 and the second tube 220, and the two adjacent second tubes 220 is plug connection and then autogenous welding.

[0037] For convenience of explanation, the assembly method of the first tube 210 and the second tube 220 will be specifically described below as an example.

[0038] As shown in Figures 3 to 9, the first pipe 210 includes a first main body portion 211 and an insertion portion 212, and the second pipe 220 includes a second main body portion 221 and a socket portion 222, the inner diameter of the socket portion 222 being larger than the outer diameter of the insertion portion 212, so that the insertion portion 212 can be attached to the socket portion 222 to form a weld bead, and welding is performed at the weld bead.

[0039] In order to control the insertion length between the first tube 210 and the second tube 220, a limiting structure is provided between the insertion portion 212 and the socket portion 222.

[0040] It goes without saying that in other embodiments, the insertion portion 212 may be provided on the second tube 220 and the socket portion 222 may be provided on the first tube 210 .

[0041] In order to realize the restriction, as shown in Fig. 3, according to one embodiment of the present application, the first tube 210 further includes a first connecting part 213, the first body part 211 is connected to the insertion part 212 through the first connecting part 213, and the diameter of the insertion part 212 is smaller than that of the first body part 211, that is, the distance between the first connecting part 213 and the central axis of the first tube 210 gradually decreases from the first body part 211 to the insertion part 212, and in order to facilitate processing, the socket part 222 and the second body part 221 have the same diameter and are integrally molded. When the insertion part 212 is inserted into the socket part 222, the first connecting part 213 stops the socket part 222 to form the above-mentioned restriction structure. That is, the first tube 210 is provided with a diameter-reducing structure, the second tube 220 has a straight cylindrical structure, and a diameter-reducing limiting structure is formed between the first tube 210 and the second tube 220.

[0042] It goes without saying that in other embodiments, the diameter-reducing structure may be provided on the second tube 220, and the first tube 210 may be a straight tube structure.

[0043] As shown in FIG. 4, according to another embodiment of the present application, the second tube 220 further includes a second connecting portion 223, and the second body portion 221 is connected to the socket portion 222 through the second connecting portion 223, and the diameter of the socket portion 222 is larger than that of the second body portion 221, that is, the distance between the second connecting portion 223 and the central axis of the second tube 220 gradually increases from the second body portion 221 to the socket portion 222, and in order to facilitate processing, the insertion portion 212 and the first body portion 211 have the same diameter and are integrally molded. When the insertion portion 212 is inserted into the socket portion 222, the second connecting portion 223 stops the insertion portion 212 to form the above-mentioned limiting structure. That is, the second tube 220 is provided with a diameter expansion structure, the first tube 210 is a straight tube structure, and a diameter expansion limiting structure is formed between the first tube 210 and the second tube 220.

[0044] When the first tube 210 and the second tube 220 are assembled using the above-mentioned diameter expansion limiting structure and then welded, the heat generated from the flame sprayed from the welding torch nozzle extends along the axial direction of the welding torch nozzle toward the insertion part 212, forming a heat-affected area in the insertion part 212. As the included angle between the central axis l of the welding torch nozzle and the central axis b of the socket part 222 gradually widens, the welding torch nozzle increasingly faces the side wall of the insertion part 212, and the possibility of the insertion part 212 melting and leaking gradually increases. Therefore, in order to ensure a good welding effect and prevent the insertion part 212 from melting, in this embodiment, the rotation angle of the welding torch is controlled so that the angle α between the extension line of the central axis l of the welding torch nozzle and the central axis b of the socket part satisfies 10°≦α≦60°.

[0045] It goes without saying that the positional requirements for the welding torch nozzle and the tube body must also satisfy the above conditions in other welding methods, and will not be described in detail here.

[0046] During the welding process, in order to ensure the welding effect, it is necessary that the molten base material of the socket part 222 is large, that is, the heat occupied by the outer socket part 222 close to the welding source is larger than that of the inner insertion part 212, and the tungsten needle of the welding torch is biased toward the socket part 222 and away from the weld bead ring, so that the weld bead is formed uniformly and plumply. In this embodiment, the heat distribution ratio when the insertion part 212 and the socket part 222 are welded is 5:5 to 6:4, and in some embodiments, the heat distribution ratio when the insertion part 212 and the socket part 222 are welded is 6:4.

[0047] It goes without saying that in other embodiments, the expanded diameter structure may be provided on the first tube 210, and the second tube 220 may be a straight tube structure.

[0048] It will be appreciated that in other embodiments, one of the first tube 210 and the second tube 220 may be provided with an enlarged diameter structure and the other with a reduced diameter structure, forming a double restriction structure.

[0049] As shown in Fig. 5 and Fig. 7, according to another embodiment of the present application, the first tube 210 and the second tube 220 use a straight insertion manner, that is, the first body part 211 and the insertion part 212 have the same diameter and are integrally molded, and the second body part 221 and the socket part 222 have the same diameter and are integrally molded, and a first limiting protrusion 214 is provided between the first body part 211 and the insertion part 212, and the first limiting protrusion 214 protrudes outward along the radial direction of the first body part 211 to stop the socket part 222 and form a limiting structure. As shown in Fig. 5, the first limiting protrusion 214 may be an annular protrusion, and as shown in Fig. 7, the first limiting protrusion 214 may be a plurality of bulges arranged at intervals. In one embodiment, the plurality of bulges are evenly distributed along the circumferential direction of the first body part 211, so that the stopping force is evenly distributed along the circumferential direction to avoid stress concentration.

[0050] As shown in Figures 6 and 8, in other embodiments, a second limiting protrusion 224 may be provided between the second body portion 221 and the socket portion 222, and the second limiting protrusion 224 may protrude inward along the radial direction of the second body portion 221 to stop the insertion portion 212 and form a limiting structure. As shown in Figure 6, the second limiting protrusion may be an annular protrusion, and as shown in Figure 8, the second limiting protrusion may be a plurality of bulges provided at intervals. In one embodiment, the plurality of bulges are evenly distributed along the circumferential direction of the second body portion 221 so that the stopping force is evenly distributed along the circumferential direction to avoid stress concentration.

[0051] In another embodiment, as shown in Figures 9 and 10, it goes without saying that the first tube 210 and the second tube 220 may be directly welded after being inserted in a straight line to an appropriate position without providing a restricting structure.

[0052] It goes without saying that the above assembly method is also applied to two adjacent second tubes 220.

[0053] It goes without saying that the above assembly method is also applied to the first pipe joint 100 and the first pipe body 210.

[0054] In this embodiment, the diameter of the second pipe fitting 200 is defined as d and d≦30mm, the weld bead gap between the first pipe body 210 and the second pipe body 220 is defined as δ and δ≦0.05mm, and the wall thickness of the second pipe fitting 200 is defined as t and t≦1.5mm. When the above-mentioned insertion connection method is used, the concentricity of the first pipe body 210 and the second pipe body 220 is good, and the deviation value of the concentricity between the first pipe body 210 and the second pipe body 220 is 0.15mm or less. The heat-affected area of ​​the pipe material welding is within 5mm near the weld bead. If the thickness of the heat-affected area after welding is uniform, the amount of reduction in the wall thickness t of the second pipe fitting 200 in this application is

[0055]

number

[0056] The amount by which the thickness t is reduced is smaller than 0.1. In other words, since the amount by which the thickness t is reduced is small, the strength of the welded portion is large.

[0057] In another embodiment, as shown in FIG. 11, the first tube 210 and the second tube 220 may be connected using a butt joint method and then welded.

[0058] Each of the technical features of the above-mentioned embodiments may be combined in any combination. For the sake of brevity, not all possible combinations of each of the technical features in the above-mentioned embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, all of them should be considered within the scope described in this specification.

[0059] The above examples merely show some embodiments of the present application, and although the description is relatively specific and detailed, it should not be understood as limiting the scope of the claims of the present application. It should be noted that those skilled in the art can make some modifications and improvements without departing from the spirit of the present application, all of which are within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the scope of the attached claims.

Claims

1. A first pipe fitting; A second pipe joint having a separate structure and including multiple stages of pipe bodies, the multiple stages of pipe bodies being arranged as a first pipe body and at least one stage of a second pipe body; Including, A pipeline for an air conditioning system, wherein one end of the first pipe body and the first pipe joint are connected by furnace welding, and the other end of the first pipe body remote from the first pipe joint and the second pipe body are connected by welding.

2. 2. The pipeline for an air conditioning system according to claim 1, wherein the first pipe joint and the first tube body are welded by solder, or the first tube body and the second tube body are welded by autogenous welding or solder, or two adjacent second tube bodies are welded by autogenous welding or solder.

3. The pipeline for an air conditioning system according to claim 1 or 2, wherein the first pipe body and the second pipe body are connected by a plug-in method and then welded.

4. 4. The pipeline for an air conditioning system according to claim 3, wherein one of the first pipe body and the second pipe body is provided with an insertion portion and the other is provided with a socket portion, and the insertion portion is inserted into the socket portion and welded.

5. 5. The pipeline for an air conditioning system according to claim 4, wherein a limiting structure is provided between the insertion portion and the socket portion to limit an insertion length between the first pipe and the second pipe.

6. 6. The pipeline for an air conditioning system as described in claim 5, wherein the one of the first pipe body and the second pipe body on which the insertion portion is provided further includes a first main body portion and a first connecting portion, the first main body portion is connected to the insertion portion via the first connecting portion, a diameter of the insertion portion is smaller than a diameter of the first main body portion, and when the insertion portion is inserted into the socket portion, the first connecting portion stops the socket portion to form the limiting structure.

7. 6. The pipeline for an air conditioning system according to claim 5, wherein the one of the first pipe and the second pipe on which the socket portion is provided further includes a second main body portion and a second connecting portion, the second main body portion is connected to the socket portion via the second connecting portion, a diameter of the socket portion is larger than a diameter of the second main body portion, and when the insertion portion is inserted into the socket portion, the second connecting portion stops the insertion portion to form the limiting structure.

8. The pipeline for an air conditioning system according to any one of claims 4 to 7, wherein the central axis of the welding torch nozzle is defined as l, the central axis of the socket portion is defined as b, and the included angle between the central axis l of the welding torch nozzle and the central axis b of the socket portion is defined as α, the α must satisfy the relational expression of 10°≦α≦60°.

9. The pipeline for an air conditioning system according to any one of claims 4 to 7, wherein a ratio of heat distribution when the insertion portion and the socket portion are welded is 5:5 to 6:

4.

10. 6. The pipeline for an air conditioning system as described in claim 5, wherein the one of the first pipe body and the second pipe body on which the insertion portion is provided further includes a first main body portion, and a first limiting protrusion is provided between the first main body portion and the insertion portion, and the first limiting protrusion protrudes outward along a radial direction of the first main body portion to stop the socket portion and form the limiting structure.

11. 6. The pipeline for an air conditioning system as described in claim 5, wherein the one of the first pipe body and the second pipe body on which the socket portion is provided further includes a second main body portion, and a second limiting protrusion is provided between the second main body portion and the socket portion, and the second limiting protrusion protrudes inward along a radial direction of the second main body portion to stop the insertion portion and form the limiting structure.

12. 4. The pipeline for an air conditioning system according to claim 3, wherein: when a diameter of the second pipe fitting is defined as d, the d satisfies a relational expression of d≦30 mm; when a weld bead gap between the first pipe body and the second pipe body is defined as δ, the δ satisfies a relational expression of δ≦0.05 mm; when a thickness of the second pipe fitting is defined as t, the t satisfies a relational expression of t≦1.5 mm; after the first pipe body and the second pipe body are connected by a plug-in method, a deviation value of concentricity between the first pipe body and the second pipe body is 0.15 mm or less; and after the first pipe body and the second pipe body are welded, an amount of reduction in the thickness t of the second pipe fitting is 1% or less.

13. The pipeline for an air conditioning system according to claim 1 or 2, wherein the first pipe body and the second pipe body are connected by a butt joint method and then welded.

14. 2. The pipeline for an air conditioning system according to claim 1, wherein the first pipe fitting comprises a copper pipe, a steel pipe or an aluminum pipe, or the second pipe fitting comprises a copper pipe, a steel pipe or an aluminum pipe.

15. The first pipe and the second pipe are connected by a butt joint and then welded, or connected by a plug joint and then welded, 2. The pipeline for an air conditioning system according to claim 1, wherein two adjacent second pipes are connected using a butt joint method and then welded, or connected using a plug-in method and then welded.

Images