Manufacturing method of continuous vacuum chamber sealing pipe fittings

Abstract

The present invention provides a manufacturing method for a continuous vacuum cavity sealed pipe fitting, comprising the following steps: 1) Connect the long pipe section seal head with the long section inner pipe fitting, and connect the long pipe section seal head with the long section outer pipe fitting; 2) Connect the fixed-length inner pipe with the long section inner pipe fitting; 3) Connect the telescopic outer pipe with the long section outer pipe fitting; 4) Clamp the outer seal and the inner seal into the middle seal, and perform a vacuum pumping treatment on the first sealed cavity; 5) Connect both the short section inner pipe fitting and the short section outer telescopic pipe with the short pipe section seal head, and connect the short pipe section seal head with the short section outer telescopic pipe; Connect the short section inner pipe fitting with the intermediate transition inner straight pipe, and connect the short section outer telescopic pipe with the intermediate transition outer straight pipe; 6) Connect the intermediate transition outer straight pipe with the external straight pipe, and perform a vacuum pumping treatment on the second sealed cavity; 7) Form a third vacuum cavity. The manufacturing method of the present invention greatly shortens the production cycle of the vacuum insulation pipe on the basis of ensuring the heat insulation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe fitting sealing structures, and particularly to a manufacturing method for continuously vacuum - chamber - sealed pipe fittings. Background Art

[0002] Vacuum - insulated pipes for continuous production generally adopt a double - layer corrugated pipe structure and are used in cryogenic projects such as long - length superconducting cables. To achieve the best heat - insulation performance, the vacuum chamber needs to be continuously penetrated and sealed at both ends, which takes a long time for vacuum treatment. The quality of the vacuum treatment directly determines the quality of its heat - insulation performance. Since the vacuum - insulated pipe mainly relies on the vacuum structure to maintain the heat - insulation performance, once the vacuum treatment is completed and sealed at both ends, it cannot be truncated again, otherwise the internal vacuum structure will be damaged. Therefore, the current production of vacuum - insulated pipes requires precise length determination. In actual cryogenic projects, if the installation and laying environment of the vacuum - insulated pipe is uncertain, it is necessary to wait until the civil engineering work is completed to obtain the exact length of the insulated pipe, resulting in a long construction period for the entire project. Producing vacuum - insulated pipes in advance also faces many risks, such as construction errors in civil engineering and temporary changes in the line, which make the length of the vacuum - insulated pipe too long or too short and unable to be installed normally.

[0003] To achieve the parallel progress of civil engineering construction and the production of vacuum - insulated pipes, the measures that can be taken include precisely controlling construction errors in civil engineering and making the length of the vacuum - insulated pipe variable. Construction errors in civil engineering are external factors and are difficult to control. To make the length of the vacuum - insulated pipe variable, two methods can be used: First, a telescopic joint with an annular corrugated pipe structure is used to adjust the length. However, the annular corrugated pipe cannot achieve continuous production and can only replace part of the length. For cryogenic projects that require continuous production of long - length corrugated pipes, the adjustable length is relatively limited. Second, a multi - section vacuum - insulated pipe structure is adopted. A certain prediction of construction errors in civil engineering is made, and a vacuum - insulated pipe that is slightly shorter than the actual length and has a relatively long total proportion is produced in advance, and the vacuum is processed. After the civil engineering is completed and the exact length is obtained, the remaining short - section vacuum - insulated pipes are produced. However, for current multi - section vacuum - insulated pipes, a sealed flange with a heat bridge structure is mostly used to connect two corrugated pipes. The heat - bridge flange only extends the heat - transfer distance, and its heat - insulation performance is much lower than that of vacuum insulation. Due to the inability to achieve continuous penetration of the vacuum chamber, there is a large amount of heat leakage at the connection of the heat - bridge flange. Summary of the Invention

[0004] In view of the above - mentioned disadvantages of the prior art, the technical problem to be solved by the present invention is to provide a manufacturing method for continuously vacuum - chamber - sealed pipe fittings that can ensure the heat - insulation performance.

[0005] To solve the above - mentioned technical problem, the present invention provides a manufacturing method for continuously vacuum - chamber - sealed pipe fittings, including the following steps:

[0006] 1) Connect the inner edge of the open end of the long pipe section seal head to one end of the long section inner pipe fitting, and connect the outer edge of the open end of the long pipe section seal head to one end of the long section outer pipe fitting. The length of the long section inner pipe fitting is greater than that of the long section outer pipe fitting. The sealed interface structure includes a fixed-length inner pipe, a telescopic outer pipe, an inner straight pipe, an outer straight pipe, and a first pipe fitting telescopic adjustment structure. Sheathe the telescopic outer pipe outside the fixed-length inner pipe, sheathe the outer straight pipe outside the inner straight pipe, connect the fixed-length inner pipe to the inner straight pipe, and connect the telescopic outer pipe to the outer straight pipe. An outer seal is provided along the circumference of the inner wall of the outer straight pipe. An inner seal is provided along the circumference of the outer wall of the inner straight pipe. A middle seal is provided on the outer side of the inner seal or the inner side of the outer seal. The middle seal is annular, and the central axis of the middle seal is collinear with the central axis of the fixed-length inner pipe. The first pipe fitting telescopic adjustment structure is provided on the telescopic outer pipe and is used to drive the telescopic outer pipe to expand and contract.

[0007] 2) Slide the telescopic outer pipe and the outer straight pipe so that one end of the fixed-length inner pipe away from the inner straight pipe is exposed, and connect the fixed-length inner pipe to the long section inner pipe fitting.

[0008] 3) Slide the telescopic outer pipe and the outer straight pipe so that the telescopic outer pipe is connected to the long section outer pipe fitting.

[0009] 4) The first pipe fitting telescopic adjustment structure drives the length of the telescopic outer pipe to shorten. At the same time, the outer straight pipe drives the outer seal to move towards the inner seal, so that the outer seal and the inner seal clamp the middle seal. The long section inner pipe fitting, the long pipe section seal head, the long section outer pipe fitting, and the sealed interface structure enclose a first sealed cavity. The first sealed cavity is evacuated to form a first vacuum cavity.

[0010] 5) Connect the inner edge of the open end of the short pipe section seal head to one end of the short section inner pipe fitting, and connect the outer edge of the open end of the short pipe section seal head to one end of the short section outer telescopic pipe. Connect the other end of the short section inner pipe fitting to the middle transition inner straight pipe, and connect the other end of the short section outer telescopic pipe to the middle transition outer straight pipe. A second pipe fitting telescopic adjustment structure is provided on the short section outer telescopic pipe and is used to drive the short section outer telescopic pipe to expand and contract. The second pipe fitting telescopic adjustment structure drives the length of the short section outer telescopic pipe to shorten, so that the length after the short section outer telescopic pipe is connected to the middle transition outer straight pipe is less than the length after the short section inner pipe fitting is connected to the middle transition inner straight pipe.

[0011] 6) After connecting the intermediate transition inner straight pipe and the inner straight pipe, the second pipe fitting telescopic adjustment structure drives the length of the short-section outer telescopic pipe to increase, connects the intermediate transition outer straight pipe and the outer straight pipe, and the intermediate transition inner straight pipe, the short-section inner pipe fitting, the short pipe section sealing head, the short-section outer telescopic pipe, the intermediate transition outer straight pipe, and the sealing interface structure enclose a second sealed cavity, and the second sealed cavity is evacuated to form a second vacuum cavity;

[0012] 7) The first pipe fitting telescopic adjustment structure drives the length of the telescopic outer pipe to increase, the second pipe fitting telescopic adjustment structure drives the length of the short-section outer telescopic pipe to shorten, the outer straight pipe drives the outer seal and the inner seal to separate, and the first vacuum cavity and the second vacuum cavity communicate to form a third vacuum cavity.

[0013] Preferably, in step 2), after connecting the fixed-length inner pipe and the long-section inner pipe fitting, an adiabatic component is wrapped on the outer side of the connection between the fixed-length inner pipe and the long-section inner pipe fitting;

[0014] In step 6), after connecting the intermediate transition inner straight pipe and the inner straight pipe, and before the second pipe fitting telescopic adjustment structure drives the length of the short-section outer telescopic pipe to increase, an adiabatic component is wrapped on the outer side of the connection between the intermediate transition inner straight pipe and the inner straight pipe.

[0015] Preferably, in step 1), an adiabatic component is wrapped on the outer side of the long-section inner pipe fitting, an adiabatic component is wrapped on the fixed-length inner pipe, and an adiabatic component is wrapped on the outer side of the inner straight pipe;

[0016] In step 5), an adiabatic component is wrapped on the outer side of the intermediate transition inner straight pipe, and an adiabatic component is wrapped on the outer side of the short-section inner pipe fitting.

[0017] Further, the adiabatic component is a multi-layer aluminized film.

[0018] Preferably, after step 4), a pressing drive structure is installed on the inner straight pipe, the pressing drive structure includes a receiving nut and a pressing rod, the receiving nut is arranged at one end of the inner straight pipe away from the fixed-length inner pipe, the pressing rod is provided with an external thread portion, the pressing rod penetrates into the receiving nut, and the external thread portion is threadedly connected with the receiving nut; by rotating the pressing rod, the pressing rod abuts against the outer seal; after step 5) and before step 6), the pressing drive structure is removed.

[0019] Preferably, in step 1), a support cylinder is sleeved on the inner seal;

[0020] One end of the support cylinder close to the long pipe section seal head has a folded portion that bends inward, and the inner diameter of the folded portion is smaller than the diameter of one end of the inner seal member close to the long pipe section seal head;

[0021] One end of the support cylinder close to the long pipe section seal head has a receiving flange that protrudes outward, the outer diameter of the receiving flange is larger than the maximum outer diameter of the inner seal member, and the outer diameter of the receiving flange is smaller than the outer diameter of the outer seal member;

[0022] In step 6), when the first pipe fitting telescopic adjustment structure drives the length of the telescopic outer pipe to shorten, and at the same time the external straight pipe drives the outer seal member to move towards the inner seal member, the outer seal member pushes the support cylinder to move.

[0023] Preferably, the first pipe fitting telescopic adjustment structure and the second pipe fitting telescopic adjustment structure are of the same structure;

[0024] The first pipe fitting telescopic adjustment structure includes a first fixing block, a second fixing block, a first fixing nut, a second fixing nut and a screw; both ends of the screw pass through the first fixing nut and the second fixing nut respectively; by rotating the screw, the screw drives the first fixing nut and the second fixing nut to move towards each other or away from each other; the first fixing nut is connected to the first fixing block, and the second fixing nut is connected to the second fixing block;

[0025] The first fixing block of the first pipe fitting telescopic adjustment structure is connected to the telescopic outer pipe; the second fixing block of the first pipe fitting telescopic adjustment structure is connected to the external straight pipe, or the second fixing block of the first pipe fitting telescopic adjustment structure is connected to the telescopic outer pipe; the axial direction of the screw of the first pipe fitting telescopic adjustment structure is parallel to the axial direction of the external straight pipe;

[0026] The first fixing block of the second pipe fitting telescopic adjustment structure is connected to the intermediate transition outer straight pipe, or the first fixing block of the second pipe fitting telescopic adjustment structure is connected to the short section outer telescopic pipe; the second fixing block of the second pipe fitting telescopic adjustment structure is connected to the short section outer telescopic pipe; the axial direction of the screw of the second pipe fitting telescopic adjustment structure is parallel to the axial direction of the intermediate transition outer straight pipe.

[0027] Preferably, the outer side surface of the inner seal member and the inner side surface of the outer seal member are both inclined surfaces; along the direction away from the long pipe section seal head, the outer part of the inner seal member has a structure with a gradually decreasing cross-sectional diameter; along the direction away from the long pipe section seal head, the inner part of the outer seal member has a structure with a gradually decreasing cross-sectional diameter.

[0028] Preferably, the inner straight pipe is connected to the inner seal through a first heat bridge, and one end of the inner straight pipe connected to the fixed-length inner pipe is connected to the first heat bridge; an adiabatic component is provided in the space between the first heat bridge and the inner straight pipe; the outer straight pipe is connected to the outer seal through a second heat bridge, and one end of the outer straight pipe connected to the telescopic outer pipe is connected to the second heat bridge; an adiabatic component is provided in the space between the second heat bridge and the outer straight pipe.

[0029] Preferably, the intermediate seal is a rubber sealing ring.

[0030] As described above, the manufacturing method of the continuous vacuum cavity sealing pipe fitting of the present invention has the following beneficial effects:

[0031] In the continuous vacuum cavity sealed pipe fitting manufactured by the manufacturing method of the continuous vacuum cavity sealed pipe fitting of the present invention, the length of the short-section inner pipe fitting is less than that of the long-section inner pipe fitting, and the length of the short-section outer telescopic pipe is less than that of the long-section outer pipe fitting; both the long-section inner pipe fitting and the long-section outer pipe fitting are connected to the long pipe section sealing head, the long-section inner pipe fitting is connected to the internal straight pipe through the fixed-length inner pipe, and the long-section outer pipe fitting is connected to the external straight pipe through the telescopic outer pipe. Then, the first pipe fitting telescopic adjustment structure drives the telescopic outer pipe to contract, the telescopic outer pipe drives the external straight pipe to move, the external straight pipe drives the outer seal to move to the outside of the inner seal, and the outer seal and the inner seal clamp the intermediate seal. At this time, the long-section inner pipe fitting, the long pipe section sealing head, the long-section outer pipe fitting, and the seal interface structure enclose the first sealed cavity, and the first sealed cavity is evacuated to form the first vacuum cavity; then the short-section inner pipe fitting is connected to the internal straight pipe through the intermediate transition inner straight pipe, and the short-section outer telescopic pipe is connected to the external straight pipe through the intermediate transition outer straight pipe. The intermediate transition inner straight pipe, the short-section inner pipe fitting, the short pipe section sealing head, the short-section outer telescopic pipe, the intermediate transition outer straight pipe, and the seal interface structure enclose the second sealed cavity, and the second sealed cavity is evacuated to form the second vacuum cavity; then the first pipe fitting telescopic adjustment structure drives the telescopic outer pipe to extend, and at the same time the second pipe fitting telescopic adjustment structure drives the short-section outer telescopic pipe to contract. The telescopic outer pipe drives the external straight pipe to move, and the external straight pipe drives the outer seal to move away from the inner seal; the outer seal is separated from the inner seal, and the outer seal and the inner seal no longer clamp the intermediate seal. The short-section outer telescopic pipe drives the intermediate transition outer straight pipe to move. At this time, the first vacuum cavity and the second vacuum cavity are connected to form the third vacuum cavity; the long-section inner pipe fitting and the long-section outer pipe fitting with a longer production ratio are produced in advance, and the vacuum treatment with a longer time consumption is carried out. After obtaining the accurate length, the short-section inner pipe fitting and the short-section outer telescopic pipe with a shorter production ratio and accurate length are produced. Finally, after the continuous vacuum cavity sealed pipe fitting is connected, the seal interface structure is opened, and the first vacuum cavity and the second vacuum cavity are continuously connected to form the third vacuum cavity. On the basis of ensuring the heat insulation performance, the production cycle of the vacuum insulation pipe is greatly accelerated, and the progress of the entire cryogenic project is shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It shows a schematic structural diagram of the long-section inner pipe fitting of the continuous vacuum cavity sealed pipe fitting of this embodiment when it is not connected to the fixed-length inner pipe and the long-section outer pipe fitting is not connected to the telescopic outer pipe.

[0033] Figure 2Schematic diagram showing that an inner seal is provided on the inner straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment.

[0034] Figure 3 Schematic diagram showing that an outer seal is provided on the outer straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment.

[0035] Figure 4 Schematic diagram showing the connection structure of the long-section inner pipe fitting and the fixed-length inner pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment.

[0036] Figure 5 Schematic diagram showing that both ends of the screw of the continuous vacuum chamber sealing pipe fitting of this embodiment penetrate into the first fixing block and the second fixing block respectively.

[0037] Figure 6 Schematic diagram showing that both ends of the screw of the continuous vacuum chamber sealing pipe fitting of this embodiment penetrate into the first fixing nut and the second fixing nut respectively.

[0038] Figure 7 Schematic diagram showing the connection structure of the long-section outer pipe fitting and the telescopic outer pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment.

[0039] Figure 8 Schematic diagram showing the structure of the outer seal and the inner seal of the continuous vacuum chamber sealing pipe fitting of this embodiment clamping the middle seal.

[0040] Figure 9 Schematic diagram showing the connection structure of the short-section inner pipe fitting and the intermediate transition inner straight pipe, and the connection structure of the short-section outer telescopic pipe and the intermediate transition outer straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment.

[0041] Figure 10 Schematic diagram showing the connection structure of the intermediate transition inner straight pipe and the inner straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment.

[0042] Figure 11 Schematic diagram showing the connection structure of the intermediate transition outer straight pipe and the outer straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment.

[0043] Figure 12 Schematic diagram showing the structure of the continuous vacuum chamber sealing pipe fitting of this embodiment when the outer seal and the inner seal are separated.

[0044] Figure 13 Schematic diagram showing the structure of the continuous vacuum chamber sealing pipe fitting of this embodiment when the first pipe fitting telescopic adjustment structure and the second pipe fitting telescopic adjustment structure are disassembled.

[0045] Figure 14Schematic diagram showing the structure when the long inner pipe fitting of the continuous vacuum chamber sealing pipe fitting of this embodiment is not connected to the fixed-length inner pipe, the long outer pipe fitting is not connected to the telescopic outer pipe, and a support cylinder is sleeved outside the internal straight pipe.

[0046] Figure 15 Schematic diagram showing the structure when the internal straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment is connected to the first heat bridge.

[0047] Figure 16 Schematic diagram showing the structure when the external straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment is connected to the second heat bridge.

[0048] Figure 17 Schematic diagram showing the structure when the long inner pipe fitting of the continuous vacuum chamber sealing pipe fitting of this embodiment is connected to the fixed-length inner pipe and a support cylinder is sleeved outside the internal straight pipe.

[0049] Figure 18 Schematic diagram showing the structure when the long outer pipe fitting of the continuous vacuum chamber sealing pipe fitting of this embodiment is connected to the telescopic outer pipe and a support cylinder is sleeved outside the internal straight pipe.

[0050] Figure 19 Schematic diagram showing the structure when the outer seal and the inner seal of the continuous vacuum chamber sealing pipe fitting of this embodiment clamp the middle seal and a support cylinder is sleeved outside the internal straight pipe.

[0051] Figure 20 Schematic diagram showing the structure when the middle transition inner straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment is connected to the internal straight pipe and a support cylinder is sleeved outside the internal straight pipe.

[0052] Figure 21 Schematic diagram showing the structure when the middle transition inner straight pipe of the continuous vacuum chamber sealing pipe fitting of this embodiment is connected to the internal straight pipe, the middle transition outer straight pipe is connected to the external straight pipe, and a support cylinder is sleeved outside the internal straight pipe.

[0053] Figure 22 Schematic diagram showing the structure when the outer seal and the inner seal of the continuous vacuum chamber sealing pipe fitting of this embodiment are separated and a support cylinder is sleeved outside the internal straight pipe.

[0054] Explanation of the reference numerals in the drawings

[0055] 110 Long inner pipe fitting

[0056] 120 Long outer pipe fitting

[0057] 130 Long pipe section seal head

[0058] 131 Open end of the long pipe section seal head

[0059] 200 Sealing interface structure

[0060] 210 Fixed-length inner tube

[0061] 220 Telescopic outer tube

[0062] 230 Inner straight tube

[0063] 231 Inner seal

[0064] 232 Outer side of the inner seal

[0065] 233 Groove

[0066] 240 Outer straight tube

[0067] 241 Outer seal

[0068] 242 Inner side of the outer seal

[0069] 250 Intermediate seal

[0070] 310 Telescopic adjustment structure for the first pipe fitting

[0071] 311 First fixing block

[0072] 312 Second fixing block

[0073] 313 First fixing nut

[0074] 314 Second fixing nut

[0075] 315 Screw rod

[0076] 320 Telescopic adjustment structure for the second pipe fitting

[0077] 410 Short inner layer pipe fitting

[0078] 420 Short outer telescopic pipe

[0079] 430 Sealing head for short pipe section

[0080] 431 Open end of the sealing head for short pipe section

[0081] 440 Intermediate transition inner straight pipe

[0082] 450 Intermediate transition outer straight pipe

[0083] 510 Connecting nut

[0084] 520 Pressing rod

[0085] 600 Heat insulation component

[0086] 710 First heat bridge

[0087] 720 Second Thermal Bridge

[0088] 800 Support tube

[0089] 810 Folding Department

[0090] 820 Receiver flange DETAILED DESCRIPTION

[0091] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0092] Please refer to the attached drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the attached drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0093] like Figures 1 to 22 As shown, the continuous vacuum chamber sealing pipe of this embodiment includes:

[0094] Long section inner pipe 110;

[0095] The long section outer pipe 120 is sleeved on the outside of the long section inner pipe 110;

[0096] The long pipe section sealing head 130, the inner edge of the opening end 131 of the long pipe section sealing head is connected to one end of the long section inner layer pipe fitting 110, and the outer edge of the opening end 131 of the long pipe section sealing head is connected to one end of the long section outer layer pipe fitting 120;

[0097] Sealing interface structure 200, the sealing interface structure 200 includes a fixed-length inner tube 210, a telescopic outer tube 220, an internal straight tube 230, an external straight tube 240, and a first pipe fitting telescopic adjustment structure 310. The telescopic outer tube 220 is sleeved outside the fixed-length inner tube 210, and the external straight tube 240 is sleeved outside the internal straight tube 230. Both ends of the fixed-length inner tube 210 are respectively connected to the long-section inner pipe fitting 110 and the internal straight tube 230, and both ends of the telescopic outer tube 220 are respectively connected to the long-section inner pipe fitting 110 and the external straight tube 240; an outer seal 241 is provided along the circumference of the inner wall of the external straight tube 240; an inner seal 231 is provided along the circumference of the outer wall of the internal straight tube 230; an intermediate seal 250 is provided on the outer side surface 232 of the inner seal or the inner side surface 242 of the outer seal. The intermediate seal 250 is annular, and the central axis of the intermediate seal 250 is collinear with the central axis of the fixed-length inner tube 210; the first pipe fitting telescopic adjustment structure 310 is arranged on the telescopic outer tube 220;

[0098] Short-section inner pipe fitting 410, the length of the short-section inner pipe fitting 410 is less than the length of the long-section inner pipe fitting 110;

[0099] Short-section outer telescopic tube 420, sleeved outside the short-section inner pipe fitting 410, and the length of the short-section outer telescopic tube 420 is less than the length of the long-section outer pipe fitting 120;

[0100] Short pipe section seal head 430, the inner edge of the open end 431 of the short pipe section seal head is connected to the short-section inner pipe fitting 410, and the outer edge of the open end 431 of the short pipe section seal head is connected to the short-section outer telescopic tube 420; the second pipe fitting telescopic adjustment structure 320 is arranged on the short-section outer telescopic tube 420;

[0101] When the first pipe fitting telescopic adjustment structure 310 drives the telescopic outer tube 220 to contract, the telescopic outer tube 220 drives the external straight tube 240 to move, and the external straight tube 240 drives the outer seal 241 to move outside the inner seal 231, and the outer seal 241 and the inner seal 231 clamp the intermediate seal 250; the short-section inner pipe fitting 410 is connected to the internal straight tube 230 through an intermediate transition inner straight tube 440, and the short-section outer telescopic tube 420 is connected to the external straight tube 240 through an intermediate transition outer straight tube 450.

[0102] In the continuous vacuum cavity sealing pipe fitting manufactured by the manufacturing method of the continuous vacuum cavity sealing pipe fitting of the present invention, the length of the short-section inner pipe fitting 410 is less than the length of the long-section inner pipe fitting 110, and the length of the short-section outer telescopic tube 420 is less than the length of the long-section outer pipe fitting 120; the long-section inner pipe fitting 110 and the long-section outer pipe fitting 120 form a relatively long pipe part; the short-section inner pipe fitting 410 and the short-section outer telescopic tube 420 form a relatively short pipe part;

[0103] Connect both the long inner pipe fitting 110 and the long outer pipe fitting 120 to the long pipe section seal head 130. Connect the long inner pipe fitting 110 to the internal straight pipe 230 through the fixed-length inner pipe 210, and connect the long outer pipe fitting 120 to the external straight pipe 240 through the telescopic outer pipe 220. Then, the first pipe fitting telescopic adjustment structure 310 drives the telescopic outer pipe 220 to contract. The telescopic outer pipe 220 drives the external straight pipe 240 to move, and the external straight pipe 240 drives the outer seal 241 to move to the outside of the inner seal 231. The outer seal 241 and the inner seal 231 clamp the intermediate seal 250. At this time, the long inner pipe fitting 110, the long pipe section seal head 130, the long outer pipe fitting 120, and the seal interface structure 200 enclose the first sealed cavity, and evacuate the first sealed cavity to form the first vacuum cavity;

[0104] Then connect the short inner pipe fitting 410 to the internal straight pipe 230 through the intermediate transition inner straight pipe 440, and connect the short outer telescopic pipe 420 to the external straight pipe 240 through the intermediate transition outer straight pipe 450. The intermediate transition inner straight pipe 440, the short inner pipe fitting 410, the short pipe section seal head 430, the short outer telescopic pipe 420, the intermediate transition outer straight pipe 450, and the seal interface structure 200 enclose the second sealed cavity, and evacuate the second sealed cavity to form the second vacuum cavity;

[0105] Then the first pipe fitting telescopic adjustment structure 310 drives the telescopic outer pipe 220 to extend, and at the same time, the second pipe fitting telescopic adjustment structure 320 drives the short outer telescopic pipe 420 to contract. The telescopic outer pipe 220 drives the external straight pipe 240 to move, and the external straight pipe 240 drives the outer seal 241 to move away from the inner seal 231; the outer seal 241 is separated from the inner seal 231, and the outer seal 241 and the inner seal 231 do not clamp the intermediate seal 250. The short outer telescopic pipe 420 drives the intermediate transition outer straight pipe 450 to move. At this time, the first vacuum cavity and the second vacuum cavity are connected to form the third vacuum cavity;

[0106] Produce the pipe section with a longer production time in advance, carry out the vacuum treatment of the pipe section with a longer production time. After obtaining the accurate length, produce the pipe section with a shorter production time. Finally, butt the pipe section with a longer production time and the pipe section with a shorter production time, and open the seal interface structure 200 to make the pipe section with a longer production time and the pipe section with a shorter production time continuously connected. The present invention enables the production of the continuous vacuum cavity sealed pipe fitting to be carried out in parallel with the civil engineering construction. On the basis of ensuring the heat insulation performance, the production cycle of the vacuum insulation pipe is greatly accelerated, and the progress of the entire cryogenic project is shortened.

[0107] The first pipe fitting telescopic adjustment structure 310 and the second pipe fitting telescopic adjustment structure 320 have the same structure; the first pipe fitting telescopic adjustment structure 310 is used to drive the telescopic outer pipe 220 to expand and contract, and the second pipe fitting telescopic adjustment structure 320 is used to drive the short-section outer telescopic pipe 420 to expand and contract;

[0108] The first pipe fitting telescopic adjustment structure 310 includes a first fixing block 311, a second fixing block 312, a first fixing nut 313, a second fixing nut 314 and a screw 315; both ends of the screw 315 pass through the first fixing nut 313 and the second fixing nut 314 respectively; by rotating the screw 315, the screw 315 drives the first fixing nut 313 and the second fixing nut 314 to move towards each other or away from each other; the first fixing nut 313 is connected to the first fixing block 311, and the second fixing nut 314 is connected to the second fixing block 312;

[0109] The first fixing block 311 of the first pipe fitting telescopic adjustment structure 310 is connected to the telescopic outer pipe 220; the second fixing block 312 of the first pipe fitting telescopic adjustment structure 310 is connected to the external straight pipe 240, or the second fixing block 312 of the first pipe fitting telescopic adjustment structure 310 is connected to the telescopic outer pipe 220; the axial direction of the screw 315 of the first pipe fitting telescopic adjustment structure 310 is parallel to the axial direction of the external straight pipe 240;

[0110] The first fixing block 311 of the second pipe fitting telescopic adjustment structure 320 is connected to the intermediate transition outer straight pipe 450, or the first fixing block 311 of the second pipe fitting telescopic adjustment structure 320 is connected to the short-section outer telescopic pipe 420; the second fixing block 312 of the second pipe fitting telescopic adjustment structure 320 is connected to the short-section outer telescopic pipe 420; the axial direction of the screw 315 of the second pipe fitting telescopic adjustment structure 320 is parallel to the axial direction of the intermediate transition outer straight pipe 450.

[0111] The first pipe fitting telescopic adjustment structure 310 and the second pipe fitting telescopic adjustment structure 320 adopt a simple structure, which is convenient for control.

[0112] In this embodiment, the first fixing block 311 is provided with a first through hole for the first fixing nut 313 to be inserted, and the second fixing block 312 is provided with a second through hole for the second fixing nut 314 to be inserted. The second fixing block 312 of the first pipe fitting telescopic adjustment structure 310 is connected to the external straight pipe 240. The first fixing block 311 of the second pipe fitting telescopic adjustment structure 320 is connected to the intermediate transition outer straight pipe 450.

[0113] The outer side surface 232 of the inner seal and the inner side surface 242 of the outer seal are both inclined surfaces; the outer side of the inner seal 231 is a structure with a cross-sectional diameter gradually decreasing in the direction away from the long pipe section sealing head 130; the inner side of the outer seal 241 is a structure with a cross-sectional diameter gradually decreasing in the direction away from the long pipe section sealing head 130. This structure facilitates the outer seal 241 and the inner seal 231 to clamp the middle seal 250, and facilitates the outer seal 241 to separate from the inner seal 231. The middle seal 250 is a rubber seal ring.

[0114] In this embodiment, the middle seal 250 is sleeved on the outer side surface 232 of the inner seal. The outer side surface 232 of the inner seal is provided with a groove 233 for the inner seal 231 to be embedded. This structure enables the middle seal 250 to be stably set on the outer side surface 232 of the inner seal.

[0115] The continuous vacuum chamber sealing pipe fitting also includes a compression driving structure, which includes a socket nut 510 and a pressure rod 520. The socket nut 510 is arranged on the end of the inner straight tube 230 away from the fixed-length inner tube 210, and the pressure rod 520 is provided with an external threaded portion. The pressure rod 520 penetrates into the socket nut 510, and the external threaded portion is threadedly connected with the socket nut 510. The pressure rod 520 is driven to move, and the pressure rod 520 pushes against the outer seal 241 and continues to move toward the inner seal 231, so that the outer seal 241 and the inner seal 231 clamp the middle seal 250, thereby strengthening the sealing effect when the outer seal 241 and the inner seal 231 clamp the middle seal 250.

[0116] The outer surface of the long inner tube 110 is covered with a heat insulating component 600, the fixed length inner tube 210 is covered with a heat insulating component 600, the outer surface of the inner straight tube 230 is covered with a heat insulating component 600, the outer surface of the intermediate transition inner straight tube 440 is covered with a heat insulating component 600, and the outer surface of the short inner tube 410 is covered with a heat insulating component 600; the connection between the long inner tube 110 and the fixed length inner tube 210 is covered with a heat insulating component 600; the connection between the intermediate transition inner straight tube 440 and the inner straight tube 230 is covered with a heat insulating component 600. The provision of the heat insulating component 600 can improve the heat insulation performance of the continuous vacuum cavity sealing pipe.

[0117] The continuous vacuum cavity sealing pipe fitting is used in cryogenic engineering, and the continuous vacuum cavity sealing pipe fitting stores cryogenic medium, such as liquid nitrogen. The inner straight pipe 230 is connected to the inner sealing member 231 through the first thermal bridge 710, and one end of the inner straight pipe 230 connected to the fixed-length inner pipe 210 is connected to the first thermal bridge 710; an insulating component 600 is provided in the interval between the first thermal bridge 710 and the inner straight pipe 230; the outer straight pipe 240 is connected to the outer sealing member 241 through the second thermal bridge 720, and one end of the outer straight pipe 240 connected to the telescopic outer pipe 220 is connected to the second thermal bridge 720; an insulating component 600 is provided in the interval between the second thermal bridge 720 and the outer straight pipe 240. The first heat bridge 710 increases the heat transfer distance of the inner seal 231, and the heat insulation component 600 provided in the interval between the first heat bridge 710 and the inner straight pipe 230 reduces the radiation heat dissipation of the inner seal 231; the second heat bridge 720 increases the heat transfer distance of the outer seal 241, and the heat insulation component 600 provided in the interval between the second heat bridge 720 and the outer straight pipe 240 reduces the radiation heat dissipation of the outer seal 241. Even if the inner seal 231 and the outer seal 241 are in contact with each other, the first heat bridge 710 and the second heat bridge 720 extend the heat transfer distance, and the heat transfer effect will not exceed the heat transfer effect of the existing multi-section vacuum insulated pipe using the heat bridge flange isolation connection method, maintaining the minimum insulation performance.

[0118] A support tube 800 is sleeved on the inner seal 231; the end of the support tube 800 close to the long tube section sealing head 130 has a folding portion 810 bent inwardly, and the inner diameter of the folding portion 810 is smaller than the diameter of the end of the inner seal 231 close to the long tube section sealing head 130; the end of the support tube 800 close to the long tube section sealing head 130 has an outwardly protruding receiving flange 820, and the outer diameter of the receiving flange 820 is larger than the maximum outer diameter of the inner seal 231, and the outer diameter of the receiving flange 820 is smaller than the outer diameter of the outer seal 241.

[0119] When the outer seal 241 moves toward the inner seal 231, the outer seal 241 pushes the receiving flange 820 to move, so that the support tube 800 moves. The continuous vacuum cavity sealing pipe is used in cryogenic engineering. The interior of the continuous vacuum cavity sealing pipe stores the cryogenic medium, which makes the long inner tube 110, the fixed length inner tube 210 and the inner straight tube 230 shrink, and the inner seal 231 moves to the inside of the support tube 800. In other words, the support tube 800 is always outside the inner seal 231, which can further reduce the radiation heat dissipation of the inner straight tube 230.

[0120] The heat-insulating component 600 is a multi-layer aluminized film. To facilitate the movement of the support cylinder 800, the outer diameter of the multi-layer aluminized film wrapped around the outside of the fixed-length inner tube 210 is smaller than the inner diameter of the support cylinder 800, the outer diameter of the multi-layer aluminized film wrapped around the outside of the long-section inner-layer pipe fitting 110 is smaller than the inner diameter of the support cylinder 800, and the outer diameter of the multi-layer aluminized film wrapped around the connection between the long-section inner-layer pipe fitting 110 and the fixed-length inner tube 210 is smaller than the inner diameter of the support cylinder 800.

[0121] In this embodiment, the support cylinder 800 is made of epoxy material. The internal straight pipe 230, the inner side seal 231, the first heat bridge 710, the external straight pipe 240, the outer side seal 241, and the second heat bridge 720 are all made of stainless steel material.

[0122] The fixed-length inner tube 210 is a stainless-steel spiral corrugated pipe or the fixed-length inner tube 210 is a stainless-steel straight pipe,

[0123] The overall stainless-steel annular corrugated pipe of the short-section outer-layer telescopic pipe 420, or any one end of the short-section outer-layer telescopic pipe 420 is a stainless-steel annular corrugated pipe. In this embodiment, the telescopic outer tube 220 and the short-section outer-layer telescopic pipe 420 are both overall stainless-steel annular corrugated pipes.

[0124] To facilitate the bending of the continuous vacuum cavity sealing pipe fitting, in this embodiment, the long-section inner-layer pipe fitting 110, the long-section outer-layer pipe fitting 120, the fixed-length inner tube 210, and the short-section inner-layer pipe fitting 410 are all stainless-steel spiral corrugated pipes.

[0125] The manufacturing method of the continuous vacuum cavity sealing pipe fitting in this embodiment includes the following steps:

[0126] 1) Connect the inner edge of the open end 131 of the long pipe section seal head to one end of the long inner pipe fitting 110, and connect the outer edge of the open end 131 of the long pipe section seal head to one end of the long outer pipe fitting 120. The length of the long inner pipe fitting 110 is greater than the length of the long outer pipe fitting 120. The seal interface structure 200 includes a fixed-length inner pipe 210, a telescopic outer pipe 220, an inner straight pipe 230, an outer straight pipe 240, and a first pipe fitting telescopic adjustment structure 310. Sheath the telescopic outer pipe 220 outside the fixed-length inner pipe 210, sheath the outer straight pipe 240 outside the inner straight pipe 230, connect the fixed-length inner pipe 210 to the inner straight pipe 230, and connect the telescopic outer pipe 220 to the outer straight pipe 240. An outer seal 241 is provided along the circumference of the inner wall of the outer straight pipe 240. An inner seal 231 is provided along the circumference of the outer wall of the inner straight pipe 230. A middle seal 250 is provided on the outer side surface 232 of the inner seal or the inner side surface 242 of the outer seal. The middle seal 250 is annular, and the central axis of the middle seal 250 is collinear with the central axis of the fixed-length inner pipe 210. The first pipe fitting telescopic adjustment structure 310 is arranged on the telescopic outer pipe 220, and the first pipe fitting telescopic adjustment structure 310 is used to drive the telescopic outer pipe 220 to expand and contract.

[0127] 2) Slide the telescopic outer pipe 220 and the outer straight pipe 240 so that the end of the fixed-length inner pipe 210 away from the inner straight pipe 230 is exposed, and connect the fixed-length inner pipe 210 to the long inner pipe fitting 110.

[0128] 3) Slide the telescopic outer pipe 220 and the outer straight pipe 240 so that the telescopic outer pipe 220 is connected to the long outer pipe fitting 120.

[0129] 4) The first pipe fitting telescopic adjustment structure 310 drives the length of the telescopic outer pipe 220 to shorten. At the same time, the outer straight pipe 240 drives the outer seal 241 to move towards the inner seal 231, so that the outer seal 241 and the inner seal 231 clamp the middle seal 250. The long inner pipe fitting 110, the long pipe section seal head 130, the long outer pipe fitting 120, and the seal interface structure 200 enclose a first sealed cavity, and the first sealed cavity is evacuated so that the first sealed cavity forms a first vacuum cavity.

[0130] 5) Connect the inner edge of the open end 431 of the short pipe section seal head to one end of the short inner layer pipe fitting 410, and connect the outer edge of the open end 431 of the short pipe section seal head to one end of the short outer layer telescopic pipe 420; connect the other end of the short inner layer pipe fitting 410 to the intermediate transition inner straight pipe 440, and connect the other end of the short outer layer telescopic pipe 420 to the intermediate transition outer straight pipe 450; the second pipe fitting telescopic adjustment structure 320 is arranged on the short outer layer telescopic pipe 420, and the second pipe fitting telescopic adjustment structure 320 is used to drive the short outer layer telescopic pipe 420 to expand and contract; the second pipe fitting telescopic adjustment structure 320 drives the length of the short outer layer telescopic pipe 420 to shorten, so that the length after the short outer layer telescopic pipe 420 is connected to the intermediate transition outer straight pipe 450 is less than the length after the short inner layer pipe fitting 410 is connected to the intermediate transition inner straight pipe 440;

[0131] 6) After connecting the intermediate transition inner straight pipe 440 to the inner straight pipe 230, the second pipe fitting telescopic adjustment structure 320 drives the length of the short outer layer telescopic pipe 420 to increase, connect the intermediate transition outer straight pipe 450 to the outer straight pipe 240, and the intermediate transition inner straight pipe 440, the short inner layer pipe fitting 410, the short pipe section seal head 430, the short outer layer telescopic pipe 420, the intermediate transition outer straight pipe 450 and the seal interface structure 200 enclose a second sealed cavity, and perform a vacuum pumping process on the second sealed cavity to form a second vacuum cavity;

[0132] 7) The first pipe fitting telescopic adjustment structure 310 drives the length of the telescopic outer pipe 220 to increase, the second pipe fitting telescopic adjustment structure 320 drives the length of the short outer layer telescopic pipe 420 to shorten, the outer straight pipe 240 drives the outer seal 241 to separate from the inner seal 231, and the first vacuum cavity and the second vacuum cavity are connected to form a third vacuum cavity.

[0133] In step 2), after connecting the fixed-length inner pipe 210 to the long inner layer pipe fitting 110, an adiabatic component 600 is wrapped on the outer side of the connection between the fixed-length inner pipe 210 and the long inner layer pipe fitting 110;

[0134] In step 6), after connecting the intermediate transition inner straight pipe 440 to the inner straight pipe 230 and before the second pipe fitting telescopic adjustment structure 320 drives the length of the short outer layer telescopic pipe 420 to increase, an adiabatic component 600 is wrapped on the outer side of the connection between the intermediate transition inner straight pipe 440 and the inner straight pipe 230.

[0135] In step 1), an adiabatic component 600 is wrapped on the outer side of the long inner layer pipe fitting 110, an adiabatic component 600 is wrapped on the fixed-length inner pipe 210, and an adiabatic component 600 is wrapped on the outer side of the inner straight pipe 230;

[0136] In step 5), an adiabatic component 600 is coated on the outer side surface of the intermediate transition inner straight pipe 440, and an adiabatic component 600 is coated on the outer side surface of the short-section inner layer pipe fitting 410.

[0137] After step 4), a pressing drive structure is installed on the inner straight pipe 230. The pressing drive structure includes a receiving nut 510 and a pressing rod 520. The receiving nut 510 is arranged at one end of the inner straight pipe 230 far from the fixed-length inner pipe 210. The pressing rod 520 is provided with an external thread portion. The pressing rod 520 penetrates into the receiving nut 510, and the external thread portion is threadedly connected with the receiving nut 510. By rotating the pressing rod 520, the pressing rod 520 abuts against the outer seal 241. After step 5) and before step 6), the pressing drive structure is removed to prevent the pressing drive structure from hindering the connection between the intermediate transition inner straight pipe 440 and the inner straight pipe 230, and to prevent the pressing drive structure from hindering the connection between the intermediate transition outer straight pipe 450 and the outer straight pipe 240.

[0138] In step 1), a support cylinder 800 is sleeved on the inner seal 231.

[0139] One end of the support cylinder 800 close to the long pipe section seal head 130 has an inwardly bent folding portion 810, and the inner diameter of the folding portion 810 is smaller than the diameter of one end of the inner seal 231 close to the long pipe section seal head 130.

[0140] One end of the support cylinder 800 close to the long pipe section seal head 130 has an outwardly protruding receiving flange 820. The outer diameter of the receiving flange 820 is larger than the maximum outer diameter of the inner seal 231, and the outer diameter of the receiving flange 820 is smaller than the outer diameter of the outer seal 241.

[0141] In step 6), when the first pipe fitting telescopic adjustment structure 310 drives the length of the telescopic outer pipe 220 to shorten, and at the same time the outer straight pipe 240 drives the outer seal 241 to move towards the inner seal 231, the outer seal 241 pushes the support cylinder 800 to move.

[0142] In this embodiment, the intermediate transition inner straight pipe 440 and the inner straight pipe 230 are welded, and the fixed-length inner pipe 210 and the long-section inner layer pipe fitting 110 are welded. A vacuum extraction hole is provided on the intermediate transition outer straight pipe 450.

[0143] The manufacturing method further includes step 8) removing the first pipe fitting telescopic adjustment structure 310 and the second pipe fitting telescopic adjustment structure 320, so that the telescopic outer pipe 220 and the short-section outer-layer telescopic pipe 420 extend under the action of the restoring force, that is, the telescopic outer pipe 220 and the short-section outer-layer telescopic pipe 420 freely rebound. After reaching equilibrium, the outer seal 241 is in the middle equilibrium position. Since both the telescopic outer pipe 220 and the short-section outer-layer telescopic pipe 420 are annular bellows, the elasticity of the annular bellows is small and is not sufficient to tightly connect the inner seal 231 and the outer seal 241. The third vacuum cavity still communicates with the first vacuum cavity and the second vacuum cavity.

[0144] In summary, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0145] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A manufacturing method of a continuous vacuum chamber sealing pipe fitting, characterized in that, Including the following steps: 1) Connect the inner edge of the open end of the long pipe section sealing head (130) to one end of the long section inner pipe fitting (110), and connect the outer edge of the open end of the long pipe section sealing head (130) to one end of the long section outer pipe fitting (120). The length of the long section inner pipe fitting (110) is greater than that of the long section outer pipe fitting (120). The sealing interface structure (200) includes a fixed-length inner pipe (210), a telescopic outer pipe (220), an inner straight pipe (230), an outer straight pipe (240), and a first pipe fitting telescopic adjustment structure (310). Sleeve the telescopic outer pipe (220) outside the fixed-length inner pipe (210), sleeve the outer straight pipe (240) outside the inner straight pipe (230), connect the fixed-length inner pipe (210) to the inner straight pipe (230), and connect the telescopic outer pipe (220) to the outer straight pipe (240). An outer seal (241) is provided along the circumference of the inner wall of the outer straight pipe (240). An inner seal (231) is provided along the circumference of the outer wall of the inner straight pipe (230). A middle seal (250) is provided on the outer side surface (232) of the inner seal or the inner side surface (242) of the outer seal. The middle seal (250) is annular, and the central axis of the middle seal (250) is collinear with the central axis of the fixed-length inner pipe (210). The first pipe fitting telescopic adjustment structure (310) is arranged on the telescopic outer pipe (220), and the first pipe fitting telescopic adjustment structure (310) is used to drive the telescopic outer pipe (220) to expand and contract; 2) Slide the telescopic outer pipe (220) and the outer straight pipe (240) so that one end of the fixed-length inner pipe (210) far from the inner straight pipe (230) is exposed, and connect the fixed-length inner pipe (210) to the long section inner pipe fitting (110); 3) Slide the telescopic outer pipe (220) and the outer straight pipe (240) so that the telescopic outer pipe (220) is connected to the long section outer pipe fitting (120); 4) The first pipe fitting telescopic adjustment structure (310) drives the length of the telescopic outer pipe (220) to shorten. At the same time, the outer straight pipe (240) drives the outer seal (241) to move towards the inner seal (231), so that the outer seal (241) and the inner seal (231) clamp the middle seal (250). The long section inner pipe fitting (110), the long pipe section sealing head (130), the long section outer pipe fitting (120), and the sealing interface structure (200) enclose a first sealed cavity, and the first sealed cavity is evacuated so that the first sealed cavity forms a first vacuum cavity; 5) Connect the inner edge of the open end of the short pipe section seal head (430) to one end of the short inner pipe fitting (410), and connect the outer edge of the open end of the short pipe section seal head (430) to one end of the short outer telescopic pipe (420); connect the other end of the short inner pipe fitting (410) to the intermediate transition inner straight pipe (440), and connect the other end of the short outer telescopic pipe (420) to the intermediate transition outer straight pipe (450); the second pipe fitting telescopic adjustment structure (320) is arranged on the short outer telescopic pipe (420), and the second pipe fitting telescopic adjustment structure (320) is used to drive the short outer telescopic pipe (420) to expand and contract; the second pipe fitting telescopic adjustment structure (320) drives the length of the short outer telescopic pipe (420) to shorten, so that the length after the short outer telescopic pipe (420) is connected to the intermediate transition outer straight pipe (450) is less than the length after the short inner pipe fitting (410) is connected to the intermediate transition inner straight pipe (440); 6) After connecting the intermediate transition inner straight pipe (440) to the inner straight pipe (230), the second pipe fitting telescopic adjustment structure (320) drives the length of the short outer telescopic pipe (420) to increase, connect the intermediate transition outer straight pipe (450) to the outer straight pipe (240), and the intermediate transition inner straight pipe (440), the short inner pipe fitting (410), the short pipe section seal head (430), the short outer telescopic pipe (420), the intermediate transition outer straight pipe (450) and the seal interface structure (200) enclose a second sealed cavity, and perform a vacuum treatment on the second sealed cavity to form a second vacuum cavity; 7) The first pipe fitting telescopic adjustment structure (310) drives the length of the telescopic outer pipe (220) to increase, the second pipe fitting telescopic adjustment structure (320) drives the length of the short outer telescopic pipe (420) to shorten, and the outer straight pipe (240) drives the outer seal (241) to separate from the inner seal (231), and the first vacuum cavity and the second vacuum cavity are communicated to form a third vacuum cavity; The first pipe fitting telescopic adjustment structure (310) and the second pipe fitting telescopic adjustment structure (320) are of the same structure; The first pipe fitting telescopic adjustment structure (310) includes a first fixing block (311), a second fixing block (312), a first fixing nut (313), a second fixing nut (314) and a screw rod (315); both ends of the screw rod (315) pass through the first fixing nut (313) and the second fixing nut (314) respectively; rotate the screw rod (315), and the screw rod (315) drives the first fixing nut (313) and the second fixing nut (314) to move towards each other or away from each other; the first fixing nut (313) is connected to the first fixing block (311), and the second fixing nut (314) is connected to the second fixing block (312); The first fixing block (311) of the first pipe fitting telescopic adjustment structure (310) is connected to the telescopic outer pipe (220); the second fixing block (312) of the first pipe fitting telescopic adjustment structure (310) is connected to the external straight pipe (240), or the second fixing block (312) of the first pipe fitting telescopic adjustment structure (310) is connected to the telescopic outer pipe (220); the axial direction of the screw rod (315) of the first pipe fitting telescopic adjustment structure (310) is parallel to the axial direction of the external straight pipe (240). The first fixing block (311) of the second pipe fitting telescopic adjustment structure (320) is connected to the intermediate transition outer straight pipe (450), or the first fixing block (311) of the second pipe fitting telescopic adjustment structure (320) is connected to the short-section outer telescopic pipe (420); the second fixing block (312) of the second pipe fitting telescopic adjustment structure (320) is connected to the short-section outer telescopic pipe (420); the axial direction of the screw rod (315) of the second pipe fitting telescopic adjustment structure (320) is parallel to the axial direction of the intermediate transition outer straight pipe (450).

2. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 1, characterized in that: In step 2), after connecting the fixed-length inner pipe (210) and the long-section inner pipe fitting (110), an adiabatic component (600) is coated on the outer side surface of the joint between the fixed-length inner pipe (210) and the long-section inner pipe fitting (110). In step 6), after connecting the intermediate transition inner straight pipe (440) and the internal straight pipe (230), and before the second pipe fitting telescopic adjustment structure (320) drives the short-section outer telescopic pipe (420) to increase in length, an adiabatic component (600) is coated on the outer side surface of the joint between the intermediate transition inner straight pipe (440) and the internal straight pipe (230).

3. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 1, characterized in that: In step 1), an adiabatic component (600) is coated on the outer side surface of the long-section inner pipe fitting (110), an adiabatic component (600) is coated on the fixed-length inner pipe (210), and an adiabatic component (600) is coated on the outer side surface of the internal straight pipe (230). In step 5), an adiabatic component (600) is coated on the outer side surface of the intermediate transition inner straight pipe (440), and an adiabatic component (600) is coated on the outer side surface of the short-section inner pipe fitting (410).

4. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 2 or 3, characterized in that: The adiabatic component (600) is a multi-layer aluminized film.

5. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 1, characterized in that: After step 4), a pressing drive structure is installed on the inner straight pipe (230). The pressing drive structure includes a receiving nut (510) and a pressing rod (520). The receiving nut (510) is arranged at one end of the inner straight pipe (230) far from the fixed-length inner pipe (210). The pressing rod (520) is provided with an external thread portion. The pressing rod (520) penetrates into the receiving nut (510), and the external thread portion is threadedly connected with the receiving nut (510). By rotating the pressing rod (520), the pressing rod (520) abuts against the outer seal (241). After step 5) and before step 6), the pressing drive structure is removed.

6. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 1, characterized in that: In step 1), a support cylinder (800) is sleeved on the inner seal (231). One end of the support cylinder (800) close to the long pipe section seal head (130) has an inwardly bent folding portion (810), and the inner diameter of the folding portion (810) is smaller than the diameter of one end of the inner seal (231) close to the long pipe section seal head (130). One end of the support cylinder (800) close to the long pipe section seal head (130) has an outwardly protruding receiving flange (820). The outer diameter of the receiving flange (820) is larger than the maximum outer diameter of the inner seal (231), and the outer diameter of the receiving flange (820) is smaller than the outer diameter of the outer seal (241). In step 6), when the first pipe fitting telescopic adjustment structure (310) drives the length of the telescopic outer pipe (220) to shorten, and at the same time the outer straight pipe (240) drives the outer seal (241) to move towards the inner seal (231), the outer seal (241) pushes the support cylinder (800) to move.

7. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 1, characterized in that: The outer side surface (232) of the inner seal and the inner side surface (242) of the outer seal are both inclined surfaces. Along the direction away from the long pipe section seal head (130), the outer part of the inner seal (231) has a structure with a gradually decreasing cross-sectional diameter. Along the direction away from the long pipe section seal head (130), the inner part of the outer seal (241) has a structure with a gradually decreasing cross-sectional diameter.

8. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 1, characterized in that: The internal straight pipe (230) is connected to the inner seal (231) through the first heat bridge (710), and one end of the internal straight pipe (230) connected to the fixed-length inner pipe (210) is connected to the first heat bridge (710); an adiabatic component (600) is provided in the interval between the first heat bridge (710) and the internal straight pipe (230); the external straight pipe (240) is connected to the outer seal (241) through the second heat bridge (720), and one end of the external straight pipe (240) connected to the telescopic outer pipe (220) is connected to the second heat bridge (720); an adiabatic component (600) is provided in the interval between the second heat bridge (720) and the external straight pipe (240).

9. The manufacturing method of the continuous vacuum cavity sealing pipe fitting according to claim 1, characterized in that: The intermediate seal (250) is a rubber sealing ring.

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