Manufacturing method of double-wall pipe

Abstract

The invention discloses a manufacturing method of a double-wall pipe. The manufacturing method comprises the following steps: (1) preparing an outer pipe and an inner pipe; (2) firstly bending the outer pipe, then cutting the outer pipe, cutting off each bent pipe section of the outer pipe, and taking the residual part on the outer pipe as each straight pipe section of the outer pipe; (3) a guide ring and all the straight pipe sections of the outer pipe are sequentially arranged on the inner pipe in a sleeving mode; (4) the inner pipe is bent, then the positions of the guide ring and the straight pipe sections of the outer pipe are adjusted, and the straight pipe sections of the outer pipe are arranged on the outer sides of the straight pipe sections of the corresponding inner pipe in a sleeving mode; and (5) each outer pipe bent pipe section is split in a half-and-half mode, then each outer pipe bent pipe section wraps the outer side of the bent pipe section of the corresponding inner pipe in a half-and-half mode, then longitudinal seams are sectioned on the two sides of each outer pipe bent pipe section for welding, and port circular seams of each outer pipe straight pipe section and the corresponding outer pipe bent pipe section are welded. The manufacturing method is simple in manufacturing, low in cost and small in welding workload, and the welding and appearance quality of the double-wall pipe can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cryogenic pressure vessels, in particular to a manufacturing method of double-wall pipe with elbow for cryogenic pressure vessels. BACKGROUND

[0002] The double-wall pipe is mostly pipe fitting with elbow, and the double-wall pipe is composed of outer pipe and inner pipe, the inner pipe is supported in the outer pipe by support structure, the cavity between the outer pipe and the inner pipe needs to be vacuumized and insulated, to isolate the air convection and heat exchange between the outer pipe and the inner pipe, effectively prevent the external heat from being transferred to the internal medium through air and pipe shell wall, and avoid the gasification of liquid phase medium. The existing support structure of double-wall pipe is relatively complex, which makes the manufacturing cost of double-wall pipe higher and the manufacturing difficulty larger. In addition, in order to install the support structure, the outer pipe needs to be cut in half during manufacturing, and after the support structure is installed, the cut outer pipe is welded and spliced to cover the outer side of the inner pipe. Since the entire outer pipe needs to be welded, the welding workload is large, and the long welds also affect the welding and appearance quality of the double-wall pipe. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a manufacturing method of double-wall pipe which is simple to manufacture, low in cost, small in welding workload, and can improve the welding and appearance quality of the double-wall pipe.

[0004] In order to solve the above problems, the technical scheme adopted by the present application is as follows: a manufacturing method of double-wall pipe, characterized in that the method steps are as follows: (1) prepare the outer pipe, the inner pipe and the guide ring, the guide ring is a low-temperature-resistant non-metallic part, the guide ring can be fitted on the inner pipe and can be in interference fit with the inner pipe, the inner pipe can be inserted into the outer pipe after the guide ring is fitted, the guide ring can ensure the coaxiality of the inner pipe and the outer pipe and play the role of supporting the inner pipe, a plurality of air grooves are arranged on the outer edge of the guide ring in a circumferential direction, and each air groove penetrates the guide ring in an axial direction; (2) first bend the outer pipe, then cut the outer pipe to cut off each outer pipe elbow section on the outer pipe, and the remaining part of the outer pipe is each outer pipe straight section; (3) fit the guide ring and each outer pipe straight section to be installed on the inner pipe in sequence according to the installation order; (4) bend the inner pipe, then adjust the positions of the guide ring and each outer pipe straight section, so that each outer pipe straight section is fitted on the outer side of the corresponding straight section of the inner pipe and is supported by the corresponding guide ring; (5) each outer pipe elbow section is respectively split in half, then each outer pipe elbow section is respectively spliced and wrapped outside the corresponding inner pipe elbow section, then the two split sides of each outer pipe elbow section are welded, and the port ring seam of each outer pipe straight section and its adjacent outer pipe elbow section is respectively welded, so that each pipe section on the outer pipe is welded through, thus obtaining the double-wall pipe.

[0005] Further, the aforementioned double-wall pipe manufacturing method, wherein: one of the two half pipes obtained by splitting each outer pipe elbow section in half is a male half pipe, and the other is a female half pipe, and a lining strip is pre-welded to the inner side of each split side of each male half pipe, so that the lining strip provides protection and reinforcement when each split longitudinal seam is welded.

[0006] Further, the aforementioned double-wall pipe manufacturing method, wherein: in step three, a lining ring is pre-fitted on the inner pipe, so that the lining ring provides protection and reinforcement when each port ring seam is welded.

[0007] Further, the aforementioned double-wall pipe manufacturing method, wherein: when the outer pipe elbow section is cut and taken, a small straight pipe section is reserved at each end of the outer pipe elbow section.

[0008] The advantages of the present application are: the double-wall pipe manufacturing method uses a simple low-temperature-resistant guide ring to support the inner pipe, greatly reducing the manufacturing cost and difficulty of the double-wall pipe; in addition, each outer pipe elbow section on the outer pipe is cut and taken, then each outer pipe elbow section is respectively welded and spliced and wrapped outside the corresponding inner pipe elbow section, and finally each pipe section on the outer pipe is welded through, so that only the elbow sections need to be welded, greatly reducing the welding workload and greatly shortening the length of the weld, so that the welding and appearance quality of the double-wall pipe can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 It is a perspective view of the double-wall pipe according to the present application.

[0010] Figure 2 It is a split view of the double-wall pipe according to the present application.

[0011] Figure 3 It is a structural view of the guide ring. DETAILED DESCRIPTION

[0012] The present application will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0013] As shown in Figure 1 , Figure 2 , Figure 3 , the double-wall pipe manufacturing method has the following steps: Prepare outer tube 1, inner tube 2, guide ring 3, guide ring 3 is low temperature resistant non-metallic parts, guide ring 3 can be installed on the inner tube 2, and can be with inner tube 2 excess fit, inner tube 2 sleeve guide ring 3 can be inserted into the outer tube 1, guide ring 3 can guarantee the coaxial of inner tube 2 and outer tube 1, and play the role of supporting inner tube 2, on the outer circle edge of guide ring 3, several air grooves 31 are arranged along the circumference, each air groove 31 penetrates the guide ring 3 in the axial direction, the air groove 31 is arranged to facilitate vacuumizing; First, bend the outer tube 1, then cut the outer tube 1, cut off each outer tube bend section 5 on the outer tube 1, the remaining part of the outer tube 1 is each outer tube straight section 4; The guide ring 3 to be installed and each outer tube straight section 4 are sequentially sleeved on the inner tube 2 according to the installation order; after the inner tube 2 is bent, some guide rings 3 and outer tube straight sections 4 cannot be sleeved in place, so the guide rings 3 and the outer tube straight sections 4 are directly sleeved in place before the inner tube 2 is bent; Bend the inner tube 2, then adjust the positions of the guide rings 3 and the outer tube straight sections 4, so that each outer tube straight section 4 is sleeved on the outer side of the straight section of the corresponding inner tube 2 and is supported by the corresponding guide ring 3; Each outer tube bend section 5 is respectively cut in half, then each outer tube bend section 5 is respectively wrapped on the outer side of the corresponding bend section of the inner tube 2, then the two sides of each outer tube bend section 5 are cut and welded, and the port ring seams of each outer tube straight section 4 and its adjacent outer tube bend section 5 are respectively welded, so that each section on the outer tube 1 is welded through, so that the double-wall pipe is obtained.

[0014] In this embodiment, one of the two half pipes obtained by cutting each outer tube bend section 5 in half is a male half pipe 7 and the other is a female half pipe 8, and a lining strip 9 is pre-welded on the inner side of the cut edge of each male half pipe 7, so that the back of each cut longitudinal seam is protected and reinforced by the lining strip 9 when it is welded.

[0015] Four lining rings 6 are pre-sleeved on the inner tube 2, so that the inner side of each port ring seam is protected and reinforced by the lining ring 6 when it is welded.

[0016] When cutting the outer tube bend section 5, a small straight tube is reserved on each end of the outer tube bend section 5, which is arranged to facilitate the assembly and welding of the port ring seam.

Claims

1. A method of manufacturing a double-walled tube, characterized by: The method steps are as follows: (1) prepare the outer tube, the inner tube, and the guide ring, the guide ring is a low-temperature-resistant non-metallic part, the guide ring can be sleeved on the inner tube and can be in interference fit with the inner tube, the inner tube can be inserted into the outer tube after the guide ring is sleeved, the guide ring can ensure that the inner tube and the outer tube are coaxial and can support the inner tube, a plurality of air grooves are arranged on the outer edge of the guide ring in the circumferential direction, and each air groove penetrates the guide ring in the axial direction; (2) first, the outer tube is bent, then the outer tube is cut, and each outer tube bending section on the outer tube is cut off, and the remaining part of the outer tube is each outer tube straight section; (3) the guide ring and each outer tube straight section are sleeved on the inner tube in the installation order; (4) the inner tube is bent, then the positions of the guide ring and each outer tube straight section are adjusted, so that each outer tube straight section is sleeved on the outer side of the corresponding straight section of the inner tube and is supported by the corresponding guide ring; (5) each outer tube bending section is cut in half, then each outer tube bending section is wrapped on the outer side of the corresponding bending section of the inner tube, then the two sides of each outer tube bending section are welded, and the port ring joints of each outer tube straight section and its adjacent outer tube bending section are welded, so that each tube section on the outer tube is welded through, thus obtaining a double-wall pipe.

2. The method of manufacturing a double-walled tube according to claim 1, characterized in that: One of the two half tubes obtained by cutting each outer tube bending section in half is a male half tube, and the other is a female half tube, a lining strip is pre-welded on the inner side of each male half tube, so that the back of each cut longitudinal joint is lined with a lining strip for protection and reinforcement when welded.

3. The method of manufacturing a double-walled tube according to claim 1 or 2, characterized in that: In step three, a lining ring is pre-sleeved on the inner tube, so that the inner side of each port ring joint is lined with a lining ring for protection and reinforcement when welded.

4. The method of manufacturing a double-walled tube according to claim 1 or 2, characterized in that: When cutting the outer tube bending section, a small straight tube is reserved on each end of the outer tube bending section.

5. The method of manufacturing a double-walled tube according to claim 3, characterized in that: When cutting the outer tube bending section, a small straight tube is reserved on each end of the outer tube bending section.

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