Pipe joint welding and positioning tool

Abstract

The utility model provides a pipe joint welding and positioning tool, which is used for assisting the welding between a pipe joint and an interlayer pipe in a liquid hydrogen bottle, and comprises a tool main body and a joint positioning part arranged on the tool main body, a first positioning part and a second positioning part are arranged on the tool main body, and the tool main body is positioned on an inner sealing head in the liquid hydrogen bottle through the first positioning part and the second positioning part; the connector positioning part comprises a positioning sleeve, a through cavity corresponding to a pipe opening of the interlayer pipe is formed in the positioning sleeve, and the through cavity is used for allowing the pipe connector to pass through and enabling the end of the pipe connector to be in butt joint with the end of the interlayer pipe. According to the pipe joint welding and positioning tool, the pipe joint can be positioned, the relative position of the pipe joint relative to an inner sealing head is guaranteed, errors in the welding process of the pipe joint and an interlayer pipe are reduced, and therefore production efficiency can be improved, the product quality of a liquid hydrogen bottle can be improved, and a good using effect is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid hydrogen bottle manufacturing tooling, in particular to a pipe joint welding positioning tooling. Background Art

[0002] Hydrogen is a globally recognized clean energy source. Currently, my country's on-board hydrogen storage systems offer both high-pressure gaseous storage and cryogenic liquid storage. Liquid hydrogen is a high-energy, low-temperature liquid fuel. Liquid hydrogen storage systems offer the advantages of both high energy density and high hydrogen storage density. This means that within a tank of the same volume, liquid hydrogen can store more hydrogen, significantly increasing the vehicle's range. Liquid hydrogen cylinders for vehicles are a key component of this technology.

[0003] During the manufacturing process of on-board liquid hydrogen cylinders, after welding one end of the sandwich tube to the inner head via a pipe joint, a pipe joint must also be welded to the other end of the sandwich tube. Because the pipe joint at the end away from the inner head needs to pass through a through-hole in the outer head and be welded to the outer head, if the pipe joint is directly welded to the sandwich tube, the relative position of the pipe joint cannot be guaranteed after welding, making the outer head welding difficult. Therefore, it is urgent to design a pipe joint welding positioning tool. Summary of the Invention

[0004] In view of this, the utility model aims to propose a pipe joint welding positioning tool to ensure the relative position of the pipe joint and reduce the error in the liquid hydrogen bottle welding process.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0006] A pipe joint welding positioning tool is used to assist in welding between a pipe joint and a sandwich tube in a liquid hydrogen bottle. The pipe joint welding positioning tool comprises a tool body and a joint positioning portion provided on the tool body;

[0007] The tool body is provided with a first positioning portion and a second positioning portion, and the tool body is positioned on the inner head of the liquid hydrogen bottle through the first positioning portion and the second positioning portion;

[0008] The joint positioning portion includes a positioning sleeve having a through cavity arranged corresponding to the tube opening of the sandwich tube. The through cavity is used for allowing the pipe joint to pass through and connect the pipe joint with the end of the sandwich tube.

[0009] Furthermore, the tooling body includes a connecting rod, and the first positioning portion and the second positioning portion are arranged at both ends of the connecting rod; the first positioning portion can be positioned at the neck tube assembly on the inner head, and the second positioning portion can be positioned at the reference inner joint on the inner head.

[0010] Furthermore, the first positioning portion includes a positioning sleeve; the positioning sleeve is sleeved on the neck tube in the neck tube assembly, and the positioning sleeve can be threadedly connected to the connecting block in the neck tube.

[0011] Furthermore, a reinforcement piece is provided between the connecting rod and the positioning sleeve.

[0012] Furthermore, a gap is left between the inner wall of the positioning sleeve and the outer wall of the neck tube, and the gap is between 0.1 mm and 0.15 mm.

[0013] Furthermore, the second positioning portion includes a first positioning plate, a second positioning plate and a third positioning plate connected in pairs, and the first positioning plate, the second positioning plate and the third positioning plate are respectively used to position different end faces of the reference inner joint.

[0014] Furthermore, a gap is left between the outer wall of the pipe joint and the inner wall of the positioning sleeve, and the gap is between 0.1 mm and 0.15 mm.

[0015] Furthermore, the joint positioning parts are multiple and are arranged in a one-to-one correspondence with the liquid supply pipe, self-pressurized air inlet pipe, air return pipe, self-pressurized air outlet pipe and liquid filling pipe in the sandwich tube.

[0016] Furthermore, the plurality of joint positioning portions are connected to the tooling body via a plurality of connecting arms in one-to-one correspondence.

[0017] Furthermore, the plurality of connecting arms are distributed radially with the first positioning portion as the center.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The pipe joint welding positioning tool described in the present invention is positioned through the tool body on the inner head in the liquid hydrogen bottle, and the joint positioning part provided on the tool body, and the through cavity in the positioning sleeve is arranged correspondingly with the pipe mouth of the sandwich pipe. The positioning sleeve is used to position the pipe joint and can be butted together with the end of the sandwich pipe, thereby ensuring the relative position of the pipe joint with respect to the inner head, reducing the error of the liquid hydrogen bottle welding process, thereby accelerating production efficiency, improving the product quality of the liquid hydrogen bottle, and having a good use effect.

[0020] In addition, the fixture body includes a connecting rod, with the first and second positioning portions located at either end of the connecting rod. This provides a simple structure and facilitates design and implementation. Furthermore, by positioning the first positioning portion on the neck tube assembly and the second positioning portion on the reference inner joint, the structure of the liquid hydrogen cylinder itself can be leveraged to better position the fixture body on the inner head, thereby improving the positioning accuracy of the pipe joint. The first positioning portion utilizes a positioning sleeve that fits over the neck tube and is threadedly connected to a connecting block within the neck tube, facilitating installation and positioning of the fixture body on the inner head and providing excellent positioning reliability.

[0021] Secondly, the reinforcement member helps to improve the connection strength between the connecting rod and the positioning sleeve, ensuring the reliability of the connection between the connecting rod and the positioning sleeve. The defined gap between the inner wall of the positioning sleeve and the outer wall of the neck tube not only facilitates the installation and removal of the positioning sleeve on the neck tube, but also effectively ensures the positioning accuracy of the positioning sleeve and thus the positioning accuracy of the tooling body.

[0022] Furthermore, the second positioning portion utilizes a first positioning plate, a second positioning plate, and a third positioning plate connected in pairs, which are used to position different end faces of the reference inner joint, respectively. This simple structure is easy to operate and use. The clearance between the outer wall of the pipe joint and the inner wall of the positioning sleeve is defined, which facilitates installation of the pipe joint and removal of the positioning tool as a whole, while also ensuring the accuracy of the relative position of the pipe joint.

[0023] In addition, the joint positioning parts are provided in a one-to-one correspondence with the liquid supply pipe, the self-pressurized air intake pipe, the return air pipe, the self-pressurized air outlet pipe and the liquid filling pipe, which can ensure the relative positions of the pipe joints at the end of the liquid supply pipe, the pipe joints at the end of the self-pressurized air intake pipe, the pipe joints at the end of the return air pipe, the pipe joints at the end of the self-pressurized air outlet pipe and the pipe joints at the end of the liquid filling pipe, thereby reducing the error in the welding process between each pipe joint and the corresponding pipe. The multiple joint positioning parts are connected to the tooling body through a one-to-one correspondence of multiple connecting arms, which has a simple structure and is also conducive to the weight reduction design of the tooling body. The multiple connecting arms are radially distributed with the first positioning part as the center, making the overall structure of the positioning tooling simple, and each joint positioning part can be based on the first positioning part, which is conducive to further improving the positioning accuracy of the pipe joints and reducing positioning errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 This is a schematic structural diagram of the pipe joint welding positioning tool according to an embodiment of the present utility model from a first perspective;

[0026] Figure 2 This is a structural schematic diagram of the pipe joint welding positioning tool according to an embodiment of the present utility model from a second perspective;

[0027] Figure 3 This is a schematic structural diagram of the pipe joint welding positioning tool according to an embodiment of the present utility model from a third perspective;

[0028] Figure 4 This is a structural diagram of the inner head and the sandwich tube in the embodiment of the present utility model;

[0029] Figure 5 This is a structural schematic diagram of the pipe joint welding positioning tooling in an application state according to an embodiment of the present utility model;

[0030] Description of reference numerals:

[0031] 1. Tool body; 2. Connecting arm; 3. Reinforcement plate; 4. Connecting bolt; 101. First positioning portion; 102. Second positioning portion; 103. Connecting rod; 201. Joint positioning portion; 1021. First positioning plate; 1022. Second positioning plate; 1023. Third positioning plate; 1001. Neck tube; 1002. Connecting block; 10021. Threaded hole;

[0032] 10. Inner head; 20. Liquid supply pipe; 30. Self-pressurized air inlet pipe; 40. Air return pipe; 50. Self-pressurized air outlet pipe; 60. Liquid filling pipe; 100. Reference inner joint; 200. Pipe joint. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0034] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," and "outer" appear to indicate orientation or positional relationships, these are based on the orientation or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, if terms such as "first" and "second" appear, they are used solely for descriptive purposes and should not be construed as indicating or implying relative importance.

[0035] Furthermore, in the description of this utility model, unless otherwise explicitly defined, the terms "mounted," "connected," "connection," and "connector" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0036] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0037] First, a liquid hydrogen cylinder, or liquid hydrogen cylinder, generally adopts a double-layer structure of an outer cylinder and an inner cylinder, with a vacuum interlayer formed between the inner and outer cylinders. The outer cylinder includes an outer cylinder body and outer heads connected to both ends of the outer cylinder body, while the inner cylinder includes an inner cylinder body and inner heads connected to both ends of the inner cylinder body. Secondly, in order to connect the interior of the inner cylinder with the exterior of the outer cylinder, it is necessary to install an interlayer pipe between the inner and outer heads. Pipe joints are welded to both ends of the interlayer pipe, and the pipe joints at both ends are welded to the inner and outer heads, respectively, thereby forming a closed channel between the inner and outer cylinders.

[0038] During the manufacturing process of the liquid hydrogen bottle, after one end of the sandwich tube is welded to the inner head through a pipe joint, a pipe joint needs to be welded to the other end of the sandwich tube. Among them, for the sake of easy distinction, the pipe joint welded to the inner head is defined as an inner joint, and the pipe joint welded to the outer head is defined as an outer joint. During the specific production, the inner joint and the outer joint need to be butt-welded to the two ends of the sandwich tube respectively. Since the pipe joint far away from one end of the inner head, that is, the outer joint, needs to pass through the through hole on the outer head and be welded to the outer head. In the prior art, after the external joint is welded to the sandwich tube, the relative position of the external joint cannot be guaranteed, which makes it difficult to weld the outer head in the later stage.

[0039] Therefore, in order to solve the problem that the relative position of the pipe joint cannot be guaranteed in the prior art, this embodiment proposes a pipe joint welding positioning tool to assist in welding the pipe joint and the sandwich tube in the liquid hydrogen bottle. Figures 1 to 3 As shown, the pipe joint welding positioning tool of this embodiment includes a tool body 1 and a joint positioning portion 201 provided on the tool body 1 .

[0040] The tool body 1 is provided with a first positioning portion 101 and a second positioning portion 102, which are used to position the tool body 1 on the inner head 10 in the liquid hydrogen bottle. The joint positioning portion 201 includes a positioning sleeve with a through cavity arranged corresponding to the tube mouth of the sandwich tube. This through cavity is used to allow the pipe joint 200 to pass through and connect the pipe joint 200 with the end of the sandwich tube.

[0041] At this time, as in the above structure, the tooling body 1 is positioned on the inner head 10 in the liquid hydrogen bottle, and the pipe joint 200 is positioned using the joint positioning portion 201 provided on the tooling body 1, so that the pipe joint 200 can be docked with the end of the sandwich tube, thereby ensuring the relative position of the pipe joint 200 relative to the inner head 10, and at the same time, the position of the sandwich tube can also be constrained, thereby reducing the error in the liquid hydrogen bottle welding process, accelerating production efficiency, and improving the product quality of the liquid hydrogen bottle.

[0042] It should be noted that the pipe joint 200 mentioned above is connected to the end of the sandwich pipe away from the inner head 10, and the pipe joint 200 is also the outer joint. The pipe joint welding positioning tool of this embodiment is used to position the outer joint to assist in welding the outer joint to the end of the sandwich pipe away from the inner head 10.

[0043] Based on the above overall structure, in detail, as a preferred embodiment, continue to refer to Figures 1 to 3 , and combined with Figure 4 and Figure 5 As shown, the tool body 1 of this embodiment includes a connecting rod 103, and a first positioning portion 101 and a second positioning portion 102 are respectively provided at both ends of the connecting rod 103. The first positioning portion 101 can be positioned at the neck tube assembly on the inner head 10, and the second positioning portion 102 can be positioned at the reference inner joint 100 on the inner head 10.

[0044] By arranging the first positioning portion 101 and the second positioning portion 102 at both ends of the connecting rod 103, the structure of the tool body 1 is relatively simple and easy to design and implement. The first positioning portion 101 is positioned on the neck tube assembly, and the second positioning portion 102 is positioned on the reference inner joint 100. In this way, the structure of the liquid hydrogen bottle itself is utilized to enable the tool body 1 to be better positioned on the inner head 10, thereby improving the positioning accuracy of the pipe joint 200.

[0045] It is worth noting that, in the structure of the inner head 10, the neck tube assembly is disposed at the raised center of the inner head 10. The neck tube assembly comprises a neck tube 1001 and a connecting block 1002 welded to the inner end of the neck tube 1001. The connecting block 1002 is used to enhance the support of the neck tube 1001. The reference inner joint 100 is one of multiple inner joints welded to the inner head 10. In this embodiment, the inner joint between the liquid-filled tube 60 in the sandwich tube and the inner head 10 is preferably used as the reference inner joint 100 for positioning.

[0046] As a preferred embodiment, the first positioning portion 101 of this embodiment includes a positioning sleeve, which is sleeved on the neck tube 1001 in the neck tube assembly and can be threadedly connected to the connecting block 1002 in the neck tube 1001. This arrangement not only facilitates the installation and positioning of the tool body 1 on the inner head 10, but also provides better positioning reliability.

[0047] In the specific implementation, as a preference, in this embodiment, a threaded hole 10021 is provided on the connecting block 1002, and correspondingly, a connecting bolt 4 is provided on the positioning sleeve. By screwing the connecting bolt 4 and the threaded hole 10021, the positioning sleeve is screwed to the connecting block 1002, so that the first positioning portion 101 can be better positioned on the neck tube assembly.

[0048] It can be understood that in addition to adopting the structural form of a positioning sleeve, the first positioning part 101 can also adopt a positioning shaft that cooperates with the neck tube assembly. One end of the positioning shaft is provided with a thread, and the positioning shaft is screwed to the threaded hole 10021 on the connecting block 1002, so that the first positioning part 101 is positioned on the neck tube assembly. This is also possible.

[0049] In this embodiment, a gap is preferably provided between the inner wall of the positioning sleeve and the outer wall of the neck tube 1001, with the gap being between 0.1 mm and 0.15 mm. In this case, defining the gap between the inner wall of the positioning sleeve and the outer wall of the neck tube 1001 facilitates installation and removal of the positioning sleeve from the neck tube 1001, while also ensuring the positioning accuracy of the positioning sleeve and, consequently, the positioning accuracy of the tooling body. In specific implementations, this gap can be set to, for example, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, or 0.15 mm.

[0050] Also preferably, in this embodiment, a gap is provided between the outer wall of the pipe joint 200 and the inner wall of the positioning sleeve, with the gap ranging from 0.1 mm to 0.15 mm. By defining the gap between the outer wall of the pipe joint 200 and the inner wall of the positioning sleeve, not only is installation of the pipe joint 200 and removal of the positioning tooling as a whole facilitated, but also ensures the relative position accuracy of the pipe joint 200. In specific implementations, this gap can be set to, for example, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, or 0.15 mm.

[0051] Still see Figures 1 to 3 As shown, in this embodiment, a reinforcement member is provided between the connecting rod 103 and the positioning sleeve, and the reinforcement member is a triangular reinforcement plate 3. The provision of such a reinforcement member is conducive to improving the connection strength between the connecting rod 103 and the positioning sleeve, ensuring the reliability of the connection between the connecting rod 103 and the positioning sleeve.

[0052] In this embodiment, the connecting rod 103 is preferably made of a stainless steel tube and includes a first rod body and a second rod body connected to each other, with the second positioning portion 102 disposed at the end of the second rod body. Furthermore, to ensure the structural strength of the connecting rod 103, a triangular reinforcement plate 3 is also disposed between the first rod body and the second rod body.

[0053] As a preferred embodiment, the second positioning portion 102 of this embodiment includes a first positioning plate 1021, a second positioning plate 1022, and a third positioning plate 1023 connected in pairs. The first positioning plate 1021, the second positioning plate 1022, and the third positioning plate 1023 are respectively used to position different end faces of the reference internal joint 100. In this case, the first positioning plate 1021, the second positioning plate 1022, and the third positioning plate 1023 are respectively used to position different end faces of the reference internal joint 100, which has the characteristics of simple structure and easy operation and use.

[0054] like Figure 4 and Figure 5 As shown, the sandwich tube connected to the inner head 10 includes a liquid supply tube 20, a self-pressurizing air inlet tube 30, an air return tube 40, a self-pressurizing air outlet tube 50, and a liquid filling tube 60. In this embodiment, the joint positioning portions 201 are provided in a plurality of manners corresponding to the liquid supply tube 20, the self-pressurizing air inlet tube 30, the air return tube 40, the self-pressurizing air outlet tube 50, and the liquid filling tube 60 in the sandwich tube. In this way, the relative positions of the pipe joints 200 at the ends of the liquid supply tube 20, the pipe joints 200 at the ends of the self-pressurizing air inlet tube 30, the pipe joints 200 at the ends of the air return tube 40, the pipe joints 200 at the ends of the self-pressurizing air outlet tube 50, and the pipe joints 200 at the ends of the liquid filling tube 60 relative to the inner head 10 can be ensured, thereby reducing the error in the welding process between each pipe joint 200 and the corresponding pipe.

[0055] Moreover, in terms of specific structure, as an example, multiple joint positioning parts 201 are connected to the tool body 1 through multiple connecting arms 2 corresponding to each other. Figures 1 to 3 As shown, a plurality of connecting arms 2 are provided on the tooling body 1, and each connecting arm 2 is provided with a joint positioning portion 201, that is, each connecting arm 2 is provided with a positioning sleeve, and each positioning sleeve corresponds one by one to the pipe joint 200 at the end of the liquid supply pipe 20, the pipe joint 200 at the end of the self-pressurized air intake pipe 30, the pipe joint 200 at the end of the return air pipe 40, the pipe joint 200 at the end of the self-pressurized air outlet pipe 50 and the pipe joint 200 at the end of the liquid filling pipe 60.

[0056] As a further preferred embodiment, in this embodiment, the plurality of connecting arms 2 are radially distributed with the first positioning portion 101 as the center. In this case, the plurality of connecting arms 2 are radially distributed with the first positioning portion 101 as the center, which simplifies the overall structure of the positioning tool, and each joint positioning portion 201 can be based on the first positioning portion 101, which is also conducive to further improving the positioning accuracy of the pipe joint 200 and reducing positioning errors.

[0057] The pipe joint welding positioning tool of this embodiment is used after the reference inner joint 100 and other inner joints are welded to the inner head 10. After the welding is completed and cooled for a certain period of time, the pipe joint welding positioning tool of this embodiment is used. In specific use, the positioning sleeve is put on the neck tube 1001, and the tool body 1 is rotated so that the second positioning part 102 is positioned on the reference inner joint 100. Then, the connecting bolt 4 is tightened into the threaded hole 10021 of the connecting block 1002 so that the tool body 1 is positioned on the inner head 10. Next, the pipe joint 200, that is, the external joint, is installed into the through cavity of the positioning sleeve, and the gap between the external joint and the tail of the sandwich tube is observed. If it is suitable, the external joint and the sandwich tube are welded. If it is not suitable, the sandwich tube is pried to a suitable position with a tool such as a crowbar to reduce the welding stress, and then the external joint and the sandwich tube are welded.

[0058] The pipe joint welding positioning tool of this embodiment can ensure the relative position of the pipe joint 200 with respect to the inner head 10, and can also keep the sandwich tube in the required specific position, thereby reducing the error in the welding process of the liquid hydrogen bottle, speeding up production efficiency, improving the product quality of the liquid hydrogen bottle, and having a good use effect and promotion significance.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pipe joint welding positioning tool for assisting the welding between a pipe joint (200) and a sandwich tube in a liquid hydrogen bottle, characterized in that: The pipe joint welding positioning tool comprises a tool body (1) and a joint positioning portion (201) provided on the tool body (1); The tool body (1) is provided with a first positioning portion (101) and a second positioning portion (102), and the tool body (1) is positioned on the inner head (10) in the liquid hydrogen bottle through the first positioning portion (101) and the second positioning portion (102); The joint positioning portion (201) comprises a positioning sleeve having a through cavity arranged corresponding to the pipe opening of the sandwich pipe, the through cavity being used for allowing the pipe joint (200) to pass through and allowing the pipe joint (200) to be butted against the end of the sandwich pipe.

2. The pipe joint welding positioning tool according to claim 1, characterized in that: The tool body (1) comprises a connecting rod (103), and the first positioning portion (101) and the second positioning portion (102) are respectively arranged at two ends of the connecting rod (103); The first positioning portion (101) can be positioned at the neck tube assembly on the inner head (10), and the second positioning portion (102) can be positioned at the reference inner joint (100) on the inner head (10).

3. The pipe joint welding positioning tool according to claim 2, characterized in that: The first positioning portion (101) includes a positioning sleeve; The positioning sleeve is sleeved on the neck tube (1001) in the neck tube assembly, and the positioning sleeve can be threadedly connected to the connecting block (1002) in the neck tube (1001).

4. The pipe joint welding positioning tool according to claim 3, characterized in that: A reinforcement piece is provided between the connecting rod (103) and the positioning sleeve.

5. The pipe joint welding positioning tool according to claim 3, characterized in that: A gap is left between the inner wall of the positioning sleeve and the outer wall of the neck tube (1001), and the gap is between 0.1 mm and 0.15 mm.

6. The pipe joint welding positioning tool according to claim 2, characterized in that: The second positioning portion (102) includes a first positioning plate (1021), a second positioning plate (1022) and a third positioning plate (1023) connected in pairs, and the first positioning plate (1021), the second positioning plate (1022) and the third positioning plate (1023) are respectively used to position different end faces of the reference inner joint.

7. The pipe joint welding positioning tool according to claim 1, characterized in that: A gap is left between the outer wall of the pipe joint (200) and the inner wall of the positioning sleeve, and the gap is between 0.1 mm and 0.15 mm.

8. The pipe joint welding positioning tool according to any one of claims 1 to 7, characterized in that: The joint positioning parts (201) are multiple and are arranged in one-to-one correspondence with the liquid supply pipe (20), the self-pressurized air inlet pipe (30), the air return pipe (40), the self-pressurized air outlet pipe (50) and the liquid filling pipe (60) in the sandwich pipe.

9. The pipe joint welding positioning tool according to claim 8, characterized in that: The plurality of joint positioning portions (201) are connected to the tooling body (1) via a plurality of connecting arms (2) corresponding to each other.

10. The pipe joint welding positioning tool according to claim 9, characterized in that: The plurality of connecting arms (2) are distributed radially with the first positioning portion (101) as the center.

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