Cable thermal insulation structure and manufacturing method

Abstract

The invention discloses a cable heat preservation structure and a manufacturing method, and belongs to the technical field of superconducting cables, and the cable heat preservation structure comprises a cable installation body, an inner cylinder assembly and an outer cylinder body; a cable is arranged in the cable mounting body in a penetrating manner; the cable mounting body is sleeved with the inner cylinder assembly, and a first heat insulation cavity is formed between the inner cylinder assembly and the cable mounting body; the inner cylinder assembly is sleeved with the outer cylinder body, a vacuum heat insulation cavity is formed between the outer cylinder body and the inner cylinder assembly, and temperature zones corresponding to the cable installation body, the inner cylinder assembly and the outer cylinder body are sequentially increased. According to the cable heat preservation structure, the environment where the cable is located is divided into the temperature of the cable, the temperature of the inner cylinder assembly and the temperature outside the outer cylinder body, that is, the environment is divided into three temperature zone ranges, heat conduction and heat radiation are reduced, and therefore the good heat preservation effect on the cable is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting cables, and particularly to a cable thermal insulation structure and a manufacturing method thereof. Background Art

[0002] The current transmission line is a key component in a nuclear fusion device. As the lifeline of the magnet system in the nuclear fusion device, it supplies power to the magnet, transmits cold mass for itself to control its own temperature to ensure stable power supply, and at the same time serves as a discharge channel for magnet energy storage in the fault state to ensure timely and safe discharge of magnet energy.

[0003] Among current transmission lines, the power supply cable for the magnet is a superconducting cable. Taking the NbTi superconducting cable as an example, the NbTi superconducting cable is a cable with niobium-titanium alloy as the superconducting material. Its Tc temperature (superconducting transition temperature) is about 8K. It must maintain the superconducting state at extremely low temperatures and needs to provide a 4.5K ultra-low temperature environment for the superconducting cable to ensure the stable operation of the magnet system. However, the temperature of the current superconducting cable is easily affected by the indoor temperature, and its thermal insulation performance is poor. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a cable thermal insulation structure, which includes the temperature of the cable itself, the temperature of the inner cylinder assembly, and the temperature outside the outer cylinder, that is, it is divided into three temperature ranges to reduce heat conduction and heat radiation, thereby achieving a better thermal insulation effect on the cable.

[0005] According to an embodiment of the present invention, the cable thermal insulation structure includes: a cable installation body, an inner cylinder assembly, and an outer cylinder; the cable installation body has a cable passing through it; the inner cylinder assembly is sleeved outside the cable installation body, and a first heat insulation cavity is formed between the inner cylinder assembly and the cable installation body; the outer cylinder is sleeved outside the inner cylinder assembly, and a vacuum heat insulation cavity is formed between the outer cylinder and the inner cylinder assembly. The temperature zones corresponding to the cable installation body, the inner cylinder assembly, and the outer cylinder increase in sequence.

[0006] According to an embodiment of the present invention, the cable thermal insulation structure includes the temperature of the cable itself, the temperature of the inner cylinder assembly, and the temperature outside the outer cylinder, that is, it is divided into three temperature ranges, which can more effectively reduce the influence of the thermal radiation of the indoor temperature on the temperature of the cable inside the inner cylinder assembly. At the same time, the vacuum heat insulation cavity also slows down the heat conduction and heat convection of the indoor temperature to the cable inside the inner cylinder assembly, improving the thermal insulation effect of the cable.

[0007] According to an embodiment of the present invention, the cable installation body includes a support body and support feet. The support body is installed with the cable, and one end of the support foot is connected to the support body, and the other end is connected to the inner wall of the inner cylinder assembly.

[0008] In the cable heat insulation structure according to an embodiment of the present invention, a heat insulation pad is provided between the support body and the support feet.

[0009] In the cable heat insulation structure according to an embodiment of the present invention, the support body is provided with a heat insulation ring, and the cable is passed through the heat insulation ring to be supported on the cable installation body.

[0010] In the cable heat insulation structure according to an embodiment of the present invention, the inner cylinder assembly includes an inner cylinder body and a cooling member, the cooling member is provided on the outer peripheral wall of the inner cylinder body, and a cooling medium is provided in the cooling member.

[0011] In the cable heat insulation structure according to an embodiment of the present invention, the inner cylinder assembly further includes a heat insulation layer, and the heat insulation layer is provided outside the cooling member.

[0012] In the cable heat insulation structure according to an embodiment of the present invention, the heat insulation layer includes at least multiple layers of composite heat insulation layers, each layer of the composite heat insulation layer includes a heat insulation sub-layer and a reflection sub-layer, the multiple layers of composite heat insulation layers are distributed radially from the inner cylinder body to the outer cylinder body, and the reflection sub-layer includes a reflection surface, and the reflection surface faces the outer cylinder body.

[0013] In the cable heat insulation structure according to an embodiment of the present invention, the heat insulation layer further includes a first heat insulation layer, a second heat insulation layer and a fastening layer, the first heat insulation layer and the second heat insulation layer are respectively located on both sides of the multiple layers of composite heat insulation layers, the thermal conductivity of the first heat insulation layer and the second heat insulation layer is lower than that of the composite heat insulation layer, the first heat insulation layer is connected to the inner cylinder body and the second heat insulation layer faces the outer cylinder body, and the fastening layer is provided outside the second heat insulation layer.

[0014] In the cable heat insulation structure according to an embodiment of the present invention, a first support structure is further provided between the inner cylinder assembly and the outer cylinder body, the first support structure includes a first support portion, a second support portion and a first heat insulation plate, the first support portion is connected to the inner cylinder assembly and the second support portion is connected to the outer cylinder body, and the first heat insulation plate is connected between the first support portion and the second support portion.

[0015] In the cable heat insulation structure according to an embodiment of the present invention, the first support portion, the second support portion and the first heat insulation plate are connected through a connection assembly, and a heat insulation bushing is provided on a part of the connection assembly that penetrates the first support portion, the second support portion and the first heat insulation plate.

[0016] In the cable heat insulation structure according to an embodiment of the present invention, the contact surface between the first heat insulation plate and the first support portion is multiple, and the contact surface with the second support portion is multiple.

[0017] The cable heat insulation structure according to an embodiment of the present invention further includes a gravity support structure. The gravity support structure includes a first connection part, a second connection part, and a support part that are distributed vertically. The first connection part is connected to the inner cylinder assembly, the second connection part is connected to the outer cylinder body, and a second heat insulation plate is provided between the first connection part and the second connection part.

[0018] For the cable heat insulation structure according to an embodiment of the present invention, the contact surface between the second heat insulation plate and the first connection part is multiple, and the contact surface between the second heat insulation plate and the second connection part is multiple.

[0019] For the cable heat insulation structure according to an embodiment of the present invention, the outer cylinder body includes a plurality of first cylinder body segments and a plurality of second cylinder body segments arranged axially. The plurality of first cylinder body segments are spaced apart axially, and the bottom of each first cylinder body segment is connected with the gravity support structure. A second cylinder body segment is connected between adjacent first cylinder body segments, and the second cylinder body segment is formed by splicing two semi-circular cylinder body segments.

[0020] For the cable heat insulation structure according to an embodiment of the present invention, the outer cylinder body is further provided with a vacuum pumping port and a vacuum gauge. The vacuum gauge measures the vacuum degree of the vacuum heat insulation cavity, and the vacuum pumping port is used for vacuum pumping.

[0021] An embodiment of the present invention also proposes a manufacturing method of a cable heat insulation structure. To manufacture the above-mentioned cable heat insulation structure, the following steps are included: threading a cable through a cable installation body; installing the cable installation body with the cable threaded therein in the inner cylinder assembly; connecting the outer cylinder body to the outer periphery of the inner cylinder assembly to form a vacuum heat insulation cavity.

[0022] For the manufacturing method of the cable heat insulation structure described above, the manufactured heat insulation structure can more effectively avoid the influence of indoor temperature heat radiation on the temperature of the cable inside the inner cylinder assembly. At the same time, the vacuum heat insulation cavity slows down the heat conduction and heat convection of the indoor temperature to the cable inside the inner cylinder assembly, improving the heat insulation effect of the cable.

[0023] For the manufacturing method of the cable heat insulation structure according to an embodiment of the present invention, after installing the cable installation body with the cable on the inner wall of the inner cylinder assembly, the following steps are further included: setting the first support part of the first support structure on the outer wall of the inner cylinder assembly, and setting the second support part of the first support structure on the inner wall of the outer cylinder body.

[0024] For the manufacturing method of the cable heat insulation structure according to an embodiment of the present invention, the step of connecting the outer cylinder body to the outer periphery of the inner cylinder assembly to form a vacuum heat insulation cavity includes: installing the inner cylinder assembly into the plurality of axially distributed first cylinder body segments of the outer cylinder body; connecting the first support part of the inner cylinder assembly with the second support part of the first cylinder body segment; connecting the second cylinder body segment between adjacent first cylinder body segments.

[0025] The manufacturing method of the cable heat insulation structure according to an embodiment of the present invention further includes, before connecting the second cylinder section between adjacent first cylinder sections: after connecting the gravity support structure to the outer wall of the first cylinder section, connecting the gravity support structure to the outer wall of the inner cylinder assembly.

[0026] The manufacturing method of the cable heat insulation structure according to an embodiment of the present invention further includes, before connecting the outer cylinder to the outer periphery of the inner cylinder assembly to form a vacuum heat insulation cavity: connecting a cooling member to the outer periphery of the inner cylinder body; pickling and passivating the surface of the inner cylinder body, and cleaning and baking; baking the heat insulation layer and connecting it to the outside of the cooling member.

[0027] The manufacturing method of the cable heat insulation structure according to an embodiment of the present invention further includes, after baking the heat insulation layer and connecting it to the outside of the cooling member: punching a plurality of vacuum holes in the heat insulation layer.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein: Figure 1 is a schematic cross-sectional structure diagram of the cable heat insulation structure according to an embodiment of the present invention; Figure 2 is a schematic diagram of the first support structure of the cable heat insulation structure according to an embodiment of the present invention; Figure 3 is a schematic diagram of the gravity support structure of the cable heat insulation structure according to an embodiment of the present invention; Figure 4 is a partial explosion schematic diagram of the connection between the outer cylinder and the inner cylinder assembly of the cable heat insulation structure according to an embodiment of the present invention; Figure 5 is a schematic diagram of the connection structure between the outer cylinder and the inner cylinder assembly of the cylinder assembly of the cable heat insulation structure according to an embodiment of the present invention; Figure 6 is a schematic diagram of the heat insulation layer according to an embodiment of the present invention; Figure 7 is a flowchart of the installation steps of the cable heat insulation structure according to an embodiment of the present invention.

[0030] Reference numerals: Cable heat insulation structure 100, Inner cylinder assembly 1, inner cylinder body 11, cooling member 12, heat insulation layer 13, composite heat insulation layer 131, reflection sub-layer 1311, heat insulation sub-layer 1312, second heat insulation layer 132, fastening layer 133, first heat insulation layer 134, first heat insulation cavity 14, outer cylinder body 2, first cylinder section 21, second cylinder section 22, vacuum pumping port 221, vacuum valve 222, vacuum gauge 223, vacuum heat insulation cavity 3, first support structure 4, first support portion 41, first horizontal support section 411, first vertical support section 412, second support portion 42, second horizontal support section 421, first connection groove 422, first heat insulation plate 43, first section 431, second section 432, third section 433, connection assembly 44, connecting rod 441, nut 442, heat insulation bushing 45, cable installation body 5, support body 51, support feet 52, heat insulation pad 53, heat insulation ring 54, cable 6, gravity support structure 7, first connection portion 71, second connection groove 711, second connection portion 72, second connection protrusion 721, second heat insulation plate 73, second horizontal section 731, vertical section 732, first horizontal section 733, support portion 74, connection bolt 75. Detailed implementation mode

[0031] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0033] Reference below Figures 1-6 The cable insulation structure 100 according to an embodiment of the present invention is described. The cable insulation structure 100 is divided into the temperature of the cable 6 itself, the temperature of the inner cylinder assembly 1, and the temperature outside the outer cylinder 2, that is, it is divided into three temperature zones. The vacuum insulation cavity 3 also slows down the heat conduction and heat convection of the indoor temperature to the cable 6 in the inner cylinder assembly 1. The heat conduction and heat radiation are reduced by setting the three temperature zones and the vacuum insulation cavity 3, thereby achieving a better insulation effect.

[0034] like Figures 1-6 As shown, a cable thermal insulation structure 100 according to an embodiment of the present invention includes: a cable installation body 5 , an inner cylinder assembly 1 and an outer cylinder 2 .

[0035] Among them, a cable 6 is passed through the cable installation body 5; the inner cylinder assembly 1 is sleeved on the outside of the cable installation body 5, and a first insulation cavity 14 is formed between the inner cylinder assembly 1 and the cable installation body 5; the outer cylinder body 2 is sleeved on the outside of the inner cylinder assembly 1, and a vacuum insulation cavity 3 is formed between the outer cylinder body 2 and the inner cylinder assembly 1. The temperature zones corresponding to the cable installation body 5, the inner cylinder assembly 1 and the outer cylinder body 2 increase successively.

[0036] In practice, cable 6 is a superconducting cable. Superconducting cables utilize superconducting materials that enter a superconducting state at a critical temperature. At this point, resistance disappears, allowing current to be transmitted without loss. This property enables superconducting cables to carry extremely high currents, with a transmission capacity far exceeding that of traditional cables. For example, a 35 kV superconducting cable can transmit the same amount of power as a 220 kV cable with extremely low line losses. Superconducting cables are commonly used in high-power transmission scenarios, such as power transmission and the construction of large-scale power networks, significantly improving power transmission efficiency and reliability.

[0037] Specifically, the cable installation body 5 can be used to install the superconducting cable. After the superconducting cable passes through multiple cable installation bodies 5, the cable installation bodies 5 can be pushed into the interior of the inner tube assembly 1 in sequence. The specific pushing method can be carried out by selecting specific tooling according to actual conditions, or by driving parts such as cylinders. Multiple cable installation bodies 5 are distributed at intervals along the inner wall of the inner tube assembly 1, so that the cable installation bodies 5 can stably support the superconducting cable.

[0038] In addition, there is a gap inside the superconducting cable, and helium can be filled into the gap. For example, liquid helium at 4.5K is used for cooling. The temperature of 4.5K is equivalent to -268.35 degrees Celsius. K is the unit of thermodynamic temperature, also known as the Kelvin scale or absolute scale. That is, at this time, the temperature of the superconducting cable is in the first temperature zone. The first heat insulation cavity 14 between the inner cylinder assembly 1 and the cable installation body 5 and the outer wall of the inner cylinder assembly 1 can be used as the second temperature zone. An outer cylinder 2 is sleeved outside the inner cylinder assembly 1, and the area outside the outer cylinder 2 is the third temperature zone. The third temperature zone can be understood as the indoor temperature. That is, the cable installation body 5 is not in direct contact with the outer cylinder 2. At the same time, after the inner cylinder assembly 1 is installed in the outer cylinder 2, a cavity can be formed between the inner cylinder assembly 1 and the outer cylinder 2, and after the cavity is evacuated, a vacuum heat insulation cavity 3 is formed. The vacuum heat insulation cavity 3 can reduce the heat conduction and heat convection between the indoor temperature area and the superconducting cable in the low-temperature working area. That is, through the combination of the three temperature zones and the setting of the vacuum heat insulation cavity 3, the stability of the temperature maintenance of the superconducting cable is improved, and the working efficiency of the superconducting cable is improved.

[0039] In some embodiments, the cable installation body 5 includes a support body 51 and support feet 52. The support body 51 is installed with a cable 6. One end of the support foot 52 is connected to the support body 51, and the other end is connected to the inner wall of the inner cylinder assembly 1.

[0040] Refer to Figure 1 As shown, a plurality of support feet 52 can be arranged around the support body 51. For example, four support feet 52 are arranged. The four support feet 52 can support on the inner peripheral wall of the inner cylinder assembly 1, so as to maintain the stability of the support body 51. The support body 51 is constructed as a square, and positions for installing the cable 6 are provided on the corresponding sides of each side length of the square of the support body 51, so that a plurality of superconducting cables can be installed on one support body 51. Moreover, the contact surface between the support foot 52 and the inner wall of the inner cylinder assembly 1 is arc-shaped and is in pressing contact, so as to facilitate the cable installation body 5 to be pushed into the inner cylinder assembly 1.

[0041] In some embodiments, a heat insulation pad 53 is provided between the support body 51 and the support feet 52. Among them, the heat insulation pad 53 can be bonded between the support body 51 and the support feet 52, or connected between the support body 51 and the support feet 52 through a connecting piece. For example, the support feet 52 are located at the four corners of the square support body 51 and extend towards the inner wall of the inner cylinder assembly 1. The positions for installing the cable 6 on the support body 51 can be arranged on both sides of the support feet 52 and are close to the support feet 52. The heat insulation pad 53 is arranged at the position of the support feet 52, reducing the heat conduction of the inner cylinder assembly 1 to the superconducting cable and further improving the heat preservation effect of the superconducting cable.

[0042] In some embodiments, the support body 51 is provided with a heat insulation ring 54, and the cable 6 passes through the heat insulation ring 54 to be supported on the cable installation body 5.

[0043] In practice, with reference to Figure 1 As shown, a heat insulation ring 54 is provided on the outer periphery of each guiding cable. The heat insulation ring 54 can be a G10 heat insulation ring 54, which is a composite material synthesized from fiberglass cloth and epoxy resin. When the superconducting cable passes through the heat insulation ring 54 of the cable installation body 5, the heat insulation ring 54 can further insulate between the cable installation body 5 and the superconducting cable, reducing the heat transfer between the superconducting cable and the cable installation body 5.

[0044] In some embodiments, the inner cylinder assembly 1 includes an inner cylinder body 11 and a cooling member 12. The cooling member 12 is provided on the outer peripheral wall of the inner cylinder body 11, and a cooling medium is provided inside the cooling member 12.

[0045] Among them, the cooling member 12 is a cooling pipe. A plurality of cooling pipes can be welded to the outer periphery of the inner cylinder body 11. The plurality of cooling pipes are equidistantly spaced along the outer periphery of the inner cylinder body 11, and each cooling pipe is filled with supercritical liquid helium at a temperature of 50K, so that the inner cylinder body 11 is within the temperature range of 50K. The main advantages of liquid helium cooling include providing extremely low temperature, excellent thermal conductivity, chemical stability, and wide applications in multiple fields. By cooling with liquid helium, a low-temperature environment is provided for the superconducting cable. When the thermal radiation in the indoor environment is not completely isolated and part of the thermal radiation reaches the outer periphery of the inner cylinder assembly 1, the heat radiation from the room temperature area can be absorbed by setting the cooling pipes, thereby reducing the temperature of the inner cylinder body 11. The indoor temperature area is the 300K room temperature area, the cooling member 12 is the 50K temperature area, and the superconducting cable is the 4.5K temperature area. That is, the setting of the cooling member 12 can reduce the thermal load of the superconducting cable.

[0046] Moreover, the plurality of cooling pipes are equidistantly spaced along the outer periphery of the inner cylinder body 11, and the heat can be absorbed more evenly at the position outside the inner cylinder assembly 1, thereby reducing the heat transfer to the cable installation body 5, that is, reducing the possibility of heat transfer to the superconducting cable.

[0047] In some embodiments, the inner cylinder assembly 1 further includes a heat insulation layer 13, and the heat insulation layer 13 is provided outside the cooling member 12.

[0048] Among them, the heat insulation layer 13 can reduce the thermal radiation of the room temperature area to the superconducting cable, that is, the heat insulation layer 13 can isolate the heat transfer between the indoor environment and the environment where the superconducting cable is located to a certain extent. And the aforementioned cooling member 12 can play a cooling role when some thermal radiation is not fully isolated. Thus, through the combination of the heat insulation layer 13 and the cooling member 12, the heat transfer between the indoor environment and the environment where the superconducting cable is located can be reduced, maintaining the temperature stability of the superconducting cable.

[0049] In some embodiments, the thermal insulation layer 13 includes at least multiple layers of composite thermal insulation layers 131. Each layer of composite thermal insulation layer 131 includes a thermal insulation sub-layer 1312 and a reflective sub-layer 1311. The multiple layers of composite thermal insulation layers 131 are distributed radially from the inner cylinder body 11 to the outer cylinder 2, and the reflective sub-layer 1311 includes a reflective surface that faces the outer cylinder 2.

[0050] Referring to Figure 6 As shown, the multiple layers of composite thermal insulation layers 131 are located in the middle region of the entire thermal insulation layer 13. Each layer of composite thermal insulation layer 131 includes a thermal insulation sub-layer 1312 and a reflective sub-layer 1311. The thermal insulation sub-layer 1312 can be fiberglass paper or plant fiber paper, and the reflective sub-layer 1311 can be aluminum paper or PET aluminized film. The PET aluminized film is a composite material formed by depositing a thin layer of aluminum on the surface of a PET film through a vacuum aluminizing process. The PET material is polyethylene terephthalate, which is a milky white or light yellow highly crystalline polymer.

[0051] Specifically, the composite thermal insulation layer 131 can be set to 30 - 40 layers. By setting the composite thermal insulation layer 131, the effect of thermal insulation can be achieved. When the indoor hot air transfers towards the inner cylinder assembly 1, the reflective sub-layer 1311 can reflect the thermal radiation from the indoor temperature zone towards the inner cylinder assembly 1, that is, reduce the heat transfer of indoor heat towards the inner cylinder assembly 1. The thermal radiation can be reduced by the reflective sub-layer 1311, and the thermal insulation sub-layer 1312 can isolate more heat, that is, part of the unisolated heat can be reflected by the reflective sub-layer 1311 and thus reduced, thereby improving the heat preservation effect of the superconducting cable.

[0052] In some embodiments, the thermal insulation layer 13 further includes a first thermal insulation layer 134, a second thermal insulation layer 132, and a fastening layer 133. The first thermal insulation layer 134 and the second thermal insulation layer 132 are respectively located on both sides of the multiple layers of composite thermal insulation layers 131. The thermal conductivity of the first thermal insulation layer 134 and the second thermal insulation layer 132 is lower than that of the composite thermal insulation layer 131. The first thermal insulation layer 134 is connected to the inner cylinder body 11 and the second thermal insulation layer 132 faces the outer cylinder 2. A fastening layer 133 is provided outside the second thermal insulation layer 132.

[0053] In practice, continue to refer to Figure 6As shown, the first thermal insulation layer 134 and the second thermal insulation layer 132 are respectively located on both sides of the multi-layer composite thermal insulation layer 131. The first thermal insulation layer 134 can be set to 3-8 layers of fiberglass paper or plant fiber paper, and the second thermal insulation layer 132 can be set to 5-10 layers of fiberglass paper. Since the thermal conductivity of the reflective sub-layer 1311 is relatively large, not setting the reflective sub-layer 1311 in the first thermal insulation layer 134 can reduce the heat conduction of the reflective sub-layer 1311 to the inner cylinder body 11. And the reflective sub-layer 1311 made of aluminum foil or aluminized film cannot withstand high temperatures. Using 5-10 layers of fiberglass for the part of the multi-layer composite thermal insulation layer 131 close to the outer cylinder 2, that is, the high-temperature resistance of fiberglass is higher than that of the reflective layer, which can avoid the influence of high temperature on the thermal insulation layer 13 when welding the outer cylinder 2 later. The fastening layer 133 can be made of fiberglass cloth, and the design of the fiberglass cloth can wrap and fasten the second thermal insulation layer 132, that is, improve the reliability of the entire thermal insulation layer 13.

[0054] In some embodiments, a first support structure 4 is further provided between the inner cylinder assembly 1 and the outer cylinder 2. The first support structure 4 includes a first support portion 41, a second support portion 42, and a first heat insulation plate 43. The first support portion 41 is connected to the inner cylinder assembly 1 and the second support portion 42 is connected to the outer cylinder 2, and a first heat insulation plate 43 is connected between the first support portion 41 and the second support portion 42.

[0055] In practice, a plurality of first support structures 4 can be provided between the outer periphery of the inner cylinder assembly 1 and the outer cylinder 2, and the plurality of first support structures 4 are circumferentially equidistantly distributed to achieve the support between the inner cylinder assembly 1 and the outer cylinder 2, thereby also forming a stable vacuum insulation cavity 3. It should be noted that before setting the thermal insulation layer 13, the first support portion 41 is connected to the outside of the inner cylinder body 11, such as welding the first support portion 41 to the outside of the inner cylinder body 11, and then setting the thermal insulation layer 13.

[0056] Specifically, the first support portion 41 is welded to the outer periphery of the inner cylinder body 11 and the second support portion 42 is welded to the inner wall of the outer cylinder 2, and a first heat insulation plate 43 is connected between the first support portion 41 and the second support portion 42. The first heat insulation plate 43 can reduce the heat transfer between the inner cylinder body 11 and the outer cylinder 2, that is, reduce the influence of the indoor temperature on the superconducting cable inside the inner cylinder body 11 and maintain the normal working environment of the superconducting cable.

[0057] In some embodiments, the first support portion 41, the second support portion 42, and the first heat insulation plate 43 are connected by a connection component 44, and a heat insulation bushing 45 is provided on the part of the connection component 44 that penetrates the first support portion 41, the second support portion 42, and the first heat insulation plate 43.

[0058] Combined Figure 2As shown, the connecting component 44 includes a connecting rod 441 and a nut 442. The end of the connecting rod 441 is provided with a thread. The connecting rod 441 passes through the first support portion 41 and the first heat insulation plate 43 and at the same time passes through the second support portion 42. The end of the connecting rod 441 is tightly connected by the nut 442. Moreover, a heat insulation sleeve 45 is provided on the part of the connecting rod 441 passing through the first support portion 41, the second support portion 42, and the first heat insulation plate 43. The heat insulation sleeve 45 can reduce the heat transfer between the first support portion 41 and the second support portion 42, and at the same time can also reduce the heat transfer between the connecting rod 441 and the first support portion 41 and the second support portion 42, thereby reducing the heat transfer between the inner cylinder body 11 and the outer cylinder 2.

[0059] In some embodiments, the contact surfaces of the first heat insulation plate 43 with the first support portion 41 are multiple, and the contact surfaces with the second support portion 42 are multiple.

[0060] Continue to refer to Figure 2 As shown, the first support portion 41 includes a first horizontal support section 411 and a first vertical support section 412. The first vertical support section 412 is perpendicular to the first horizontal support section 411, and the first vertical support section 412 is provided in the middle area of the first horizontal support section 411 to reserve a space for installing the first heat insulation plate 43 at the end of the first horizontal support section 411. The first heat insulation plate 43 includes a third section 433 and two second sections 432 bent and connected at both ends of the third section 433. The two second sections 432 are perpendicular to the third section 433 respectively, and the two second sections 432 are parallel to each other. The first section 431 is perpendicular to the second section 432, and the first section 431, the second section 432, and the third section 433 are integrally formed. The first section 431 of the first heat insulation plate 43 contacts the first vertical support section 412, and the two second sections 432 contact both sides of the first horizontal support section 411, and the third section 433 contacts the end of the first horizontal support section 411.

[0061] The second support portion 42 includes a second horizontal support section 421 and a first connection groove 422 provided at one end of the second horizontal support section 421. At least a part of the side of the first heat insulation plate 43 facing the outer cylinder 2 is located in the first connection groove 422, and the side facing the inner cylinder assembly 1 contacts the first horizontal support section 411 and the first vertical support section 412 respectively. That is, the contact surfaces of one side of the first heat insulation plate 43 with the first support portion 41 are multiple, and the contact surfaces of the other side of the first heat insulation plate 43 with the second support portion 42 are also multiple, which can not only ensure the connection reliability between the first heat insulation plate 43 and the first support portion 41 and the second support portion 42, but also isolate all the contact surfaces between the first support portion 41 and the second support portion 42, thereby improving the blocking effect of the first heat insulation plate 43 on the heat transfer between the first support portion 41 and the second support portion 42, and further reducing the heat transfer between the inner cylinder assembly 1 and the outer cylinder 2.

[0062] In some embodiments, the cable thermal insulation structure 100 further includes a gravity support structure 7. The gravity support structure 7 includes a first connection portion 71, a second connection portion 72, and a support portion 74 that are distributed vertically. The first connection portion 71 is connected to the inner cylinder assembly 1, the second connection portion 72 is connected to the outer cylinder body 2, and a second heat insulation plate 73 is provided between the first connection portion 71 and the second connection portion 72.

[0063] Combined Figure 1 and Figure 3 As shown, the gravity support structure 7 includes a first connection portion 71 and a second connection portion 72 that are spaced apart vertically. Both the first connection portion 71 and the second connection portion 72 are configured as arcs. The first connection portion 71 is connected to the outer wall of the inner cylinder body 11, the second connection portion 72 is connected to the outer wall of the outer cylinder body 2, and a support portion 74 is connected to the bottom of the second connection portion 72. The support portion 74 supports the first connection portion 71 and the second connection portion 72. By providing the arc-shaped first connection portion 71 and second connection portion 72, the outer peripheral shapes of the inner cylinder body 11 and the outer cylinder body 2 can be adapted respectively, and the inner cylinder body 11 and the outer cylinder body 2 are supported through the gravity support structure 7. Moreover, the second heat insulation plate 73 between the first connection portion 71 and the second connection portion 72 can reduce the heat transfer between the inner cylinder body 11 and the outer cylinder body 2 along the gravity support structure 7, thereby reducing the influence of the outdoor temperature on the temperature of the superconducting cable.

[0064] In some embodiments, the contact surface between the second heat insulation plate 73 and the first connection portion 71 is multiple, and the contact surface between the second heat insulation plate 73 and the second connection portion 72 is multiple.

[0065] Specifically, a second connection groove 711 is provided at one end of the first connection portion 71, a second connection protrusion 721 is provided at one end of the second connection portion 72. The second heat insulation plate 73 includes a first transverse section 733 and vertical sections 732 bent and connected at both ends of the first transverse section 733. And second transverse sections 731 are connected to the ends of the two vertical sections 732 away from each other. The first transverse section 733 and the two vertical sections 732 of the second heat insulation plate 73 are located in the second connection groove 711 of the first connection portion 71, and the second transverse section 731 is located at the end of the second connection groove 711 close to the second connection portion 72. The second connection protrusion 721 of the second connection portion 72 extends into the space between the two vertical sections 732 of the second heat insulation plate 73, and the second connection protrusion 721 presses the second heat insulation plate 73 in the second connection groove 711, and the second connection protrusion 721, the second connection groove 711, and the second heat insulation plate 73 are connected and fixed by a connection bolt 75.

[0066] That is to say, the contact surfaces between the second heat insulation plate 73 and the first connecting part 71 are provided in multiple numbers, and the contact surfaces with the second connecting part 72 are also provided in multiple numbers. This can not only improve the connection reliability between the second heat insulation plate 73, the first connecting part 71 and the second connecting part 72, but also insulate all the contact surfaces, thereby enhancing the heat insulation effect on the first connecting part 71 and the second connecting part 72.

[0067] In some embodiments, the outer cylinder 2 includes a plurality of first cylinder segments 21 and second cylinder segments 22 arranged axially. The plurality of first cylinder segments 21 are spaced apart axially, and a gravity support structure 7 is connected to the bottom of each first cylinder segment 21. A second cylinder segment 22 is connected between adjacent first cylinder segments 21, and the second cylinder segment 22 is formed by splicing two semi-circular cylinder segments.

[0068] Combined Figure 4 and Figure 5 As shown, a plurality of first cylinder segments 21 are provided. The plurality of first cylinder segments 21 are distributed at intervals axially. First, the inner cylinder assembly 1 is inserted into the interiors of the plurality of first cylinder segments 21. At this time, the first support structure 4 between the inner cylinder assembly 1 and the outer cylinder 2 can be connected, and the first connecting part 71 of the gravity support structure 7 is also connected to the inner cylinder body 11. Then, the second connecting part 72 of the gravity support structure 7 is connected to the outer cylinder 2, realizing the support of the gravity support structure 7 for the inner cylinder body 11 and the outer cylinder 2.

[0069] The first support part 41 and the second support part 42 are connected through a connecting component 44, and the first support structure 4 and the gravity support structure 7 are staggered at intervals in the circumferential direction. By setting the outer cylinder 2 as a plurality of spaced-apart first cylinder segments 21, after the inner cylinder body 11 is inserted into the plurality of spaced-apart first cylinder segments 21, it is convenient to connect the gravity support structure 7 to the inner cylinder body 11 and the outer cylinder 2, and at the same time, it is also convenient to connect the first support part 41 and the second support part 42.

[0070] After the gravity support structure 7 is connected to the inner cylinder body 11 and the outer cylinder 2, and the first support structure 4 is connected to the inner cylinder body 11 and the outer cylinder 2, then the second cylinder segment 22 is connected to two adjacent first cylinder segments 21. The second cylinder segment 22 is formed by splicing two semi-circular cylinder segments, which is convenient for the second cylinder segment 22 to be connected to the inner cylinder body 11 and also convenient for the second cylinder segment 22 to be connected to the first cylinder segment 21. At this time, the outer cylinder 2 can entirely surround the outer periphery of the inner cylinder body 11, forming a vacuum insulation cavity 3, thereby reducing heat transfer and achieving the heat preservation effect on the inner cylinder body 11.

[0071] In some embodiments, the outer cylinder 2 is further provided with a vacuum pumping port 221 and a vacuum gauge 223. The vacuum gauge 223 measures the vacuum degree of the vacuum insulation cavity 3, and the vacuum pumping port 221 is used for vacuum pumping.

[0072] In practice, refer to Figure 4 As shown, the outer cylinder 2 is provided with a vacuum port 221, which is provided with a vacuum valve 222. A vacuum gauge 223 is also provided on one side of the vacuum port 221. This allows for evacuation and vacuum level monitoring of the vacuum insulation chamber 3 formed between the outer cylinder 2 and the inner cylinder body 11. For example, if the vacuum level cannot be achieved within 24 hours and remains at 0.1 Pa after 24 hours, heating and nitrogen replacement are performed at 80°C for 4-6 hours before further evacuation. Once the required vacuum level is met, the vacuum valve 222 is closed. Since the insulation layer 13 may adsorb large, difficult-to-extract gases such as water molecules and oil, heating and nitrogen replacement can expel these gases. By monitoring the vacuum level with the vacuum gauge 223, the vacuum insulation chamber 3 formed between the outer cylinder 2 and the inner cylinder assembly 1 is maintained in a vacuum state as much as possible, thereby reducing heat conduction and convection from the room temperature region to the superconducting cable in the low-temperature operating region.

[0073] The embodiment of the present invention also discloses a method for manufacturing a cable insulation structure, such as Figure 7 As shown, manufacturing the above-mentioned cable insulation structure 100 includes the following steps: S1: Pass the cable 6 through the cable installation body 5; that is, first pass the superconducting cable through multiple cable installation bodies 5. For example, the cable installation body 5 is provided with multiple insulation rings 54, and the insulation rings 54 are provided with penetration holes. The superconducting cable passes through the penetration holes of the multiple cable installation bodies 5 to achieve the connection between the superconducting cable and the multiple cable installation bodies 5.

[0074] S2: Install the cable installation body 5 on the inner wall of the inner cylinder assembly 1; push the multiple cable installation bodies 5 into the inner cylinder body 11. Specifically, a special tool such as a cylinder or other feasible tools can be used to assist in pushing the cable installation body 5 into the inner cylinder body 11, so that the multiple cable installation bodies 5 support the superconducting cable.

[0075] S3: Connect the outer cylinder 2 to the outer periphery of the inner cylinder assembly 1 to form a vacuum insulation cavity 3. After the inner cylinder assembly 1 is connected to the inside of the outer cylinder 2 and a cavity is formed between the inner cylinder assembly 1 and the outer cylinder 2, the cavity is evacuated, and at the same time, the vacuum degree is detected by a vacuum gauge 223. If the vacuum degree cannot reach the required value within 24 hours and remains at 0.1 Pa after 24 hours, heating and nitrogen replacement are performed. The heating temperature is 80 °C and is maintained for 4 to 6 hours, and then evacuation is performed again. After the vacuum degree meets the requirements, the vacuum valve 222 is closed. Since water molecules, grease and other large molecules of gas that are difficult to evacuate will be adsorbed on the heat insulation layer 13, heating and nitrogen replacement can expel the large molecules of gas that are difficult to evacuate. The vacuum degree is detected by the vacuum gauge 223, so that the vacuum insulation cavity 3 formed between the outer cylinder 2 and the inner cylinder assembly 1 is kept in a vacuum state as much as possible, slowing down the heat conduction and heat convection of the superconducting cable in the room temperature area to the low-temperature working area.

[0076] In some embodiments, after a cable installation body 5 for installing a cable 6 is provided on the inner wall of the inner cylinder assembly 1, it further includes: a first support portion 41 of a first support structure 4 is provided on the outer wall of the inner cylinder assembly 1, and a second support portion 42 of the first support structure 4 is provided on the inner wall of the outer cylinder 2.

[0077] Among them, after keeping the outer surfaces of the inner cylinder body 11 and the outer cylinder 2 clean, the first support portion 41 can be welded to the inner cylinder body 11 by argon arc welding, and the second support portion 42 can be welded to the outer cylinder 2 by argon arc welding. When connecting the inner cylinder body 11 and the outer cylinder 2, it is more convenient, and it is also convenient to provide a heat insulation pad 53 between the first support portion 41 and the second support portion 42, so as to prepare for the connection and support of the inner cylinder body 11 and the outer cylinder 2.

[0078] In some embodiments, connecting the outer cylinder 2 to the outer periphery of the inner cylinder assembly 1 to form a vacuum insulation cavity 3 includes: S31: Install the inner cylinder assembly 1 into a plurality of first cylinder segments 21 axially distributed in the outer cylinder 2; that is, after the inner cylinder assembly 1 first passes through a plurality of axially distributed first cylinder segments 21, it is convenient to connect the first support structure 4 between the inner cylinder body 11 and the outer cylinder 2.

[0079] S32: Connect the first support portion 41 of the inner cylinder assembly 1 to the second support portion 42 of the first cylinder segment 21; for example, connect a first heat insulation plate 43 between the first support portion 41 and the second support portion 42, so as to reduce the heat transfer between the inner cylinder body 11 and the outer cylinder 2 at the first support structure 4 and keep the temperature of the superconducting cable within the preset range all the time. Moreover, when connecting the first support portion 41 and the second support portion 42, it can be extended into the space between the inner cylinder body 11 and the outer cylinder 2 along the axial end of the first cylinder segment 21 of the outer cylinder 2 for connection. Thus, the convenience of connection can be improved.

[0080] S33: Connect the second barrel segments 22 between adjacent first barrel segments 21. Specifically, the second barrel segments 22 include two oppositely disposed semicircular structures. First, the two semicircular second barrel segments 22 are welded relative to each other around the outer circumference of the inner barrel body 11. Then, one end of the second barrel segment 22 is welded to one end of the first barrel segment 21, thereby achieving the connection between the first barrel segment 21 and the second barrel segment 22. After welding, non-destructive testing such as radiographic testing and leak rate testing is performed to improve the integrity and sealing of the outer barrel 2 and reduce heat radiation and heat transfer.

[0081] In some embodiments, before connecting the second barrel segments 22 between adjacent first barrel segments 21 , the process further includes: connecting the gravity support structure 7 to the outer wall of the first barrel segment 21 , and then connecting the gravity support structure 7 to the outer wall of the inner barrel assembly 1 .

[0082] That is, after the first support structure 4 between the inner cylinder body 11 and the outer cylinder body 2 is connected, the first connection part 71, the second connection part 72 and the second heat insulation board 73 are connected to form an integral gravity support structure 7, and the second connection part 72 of the gravity support structure 7 is connected to the outer periphery of the first cylinder segment 21. At the same time, the first connection part 71 is welded to the outer periphery of the inner cylinder body 11. Of course, it is also possible to decide whether to first connect the gravity support structure 7 to the first cylinder segment 21 or to first connect to the inner cylinder body 11 according to the convenience of actual connection, so as to realize the support of the inner cylinder body 11 and the outer cylinder 2 by the gravity support structure 7.

[0083] That is, each first cylinder segment 21 of the outer cylinder 2 is used to connect the gravity support structure 7 and the first support structure 4 , and the second cylinder segment 22 is used to connect adjacent first cylinder segments 21 .

[0084] In some embodiments, before connecting the outer cylinder 2 to the outer periphery of the inner cylinder assembly 1 to form the vacuum insulation chamber 3, the method further includes: S21: Connect the cooling element 12 to the outer periphery of the inner cylinder body 11; before connecting the cooling element 12 to the outer wall of the inner cylinder body 11, first clean the outer periphery of the inner cylinder body 11 to keep the surface clean, and then weld the cooling elements 12 to the outer periphery of the inner cylinder body 11 at intervals along the circumferential direction. After welding, perform non-destructive testing such as radiographic testing and leak rate testing. After welding, the cooling element 12 meets the leakage rate requirement of less than 1x10 at a pressure of 30 bar. -9 Pa·m 3 / s.

[0085] It should be noted that when welding the first support portion 41 on the outer wall of the inner cylinder body 11 and the second support portion 42 on the inner wall of the outer cylinder body 2, and when welding the first connection portion 71 of the gravity support structure 7 on the outer wall of the inner cylinder body 11 and the second connection portion 72 of the gravity support structure 7 on the outer wall of the outer cylinder body 2, non-destructive tests such as radiographic inspection and leak rate inspection shall be carried out after welding to ensure the sealing performance and reliability of the welding, thereby improving the stability of the overall structure.

[0086] S22: Pickle and passivate the surface of the inner cylinder body 11, and then clean and bake it; use distilled water for cleaning during cleaning, and bake it at 120 °C after cleaning to reduce the attachment of impurities on the outer surface of the inner cylinder body 11, thereby improving the vacuum degree of the space between the inner cylinder body 11 and the outer cylinder body 2 after evacuation. Baking the inner cylinder body 11 at 120 °C can reduce the gas adsorption amount on the surface of the inner cylinder body 11, thereby reducing the gas pressure between the inner cylinder body 11 and the outer cylinder body 2 and improving the vacuum degree.

[0087] S23: Bake the heat insulation layer 13 and connect it to the outside of the cooling member 12. In practice, before wrapping the heat insulation layer 13, place the heat insulation layer 13 in a nitrogen box and bake it at 80 °C for 24 hours. Baking can remove impurities such as moisture, grease, wax, and alkali, accelerate the outgassing of the heat insulation layer 13, and shorten the subsequent evacuation time.

[0088] Moreover, before wrapping the multi-layer composite heat insulation layer 131 of the heat insulation layer 13, or the multi-layer first heat insulation layer 134 and the multi-layer second heat insulation layer 132, it is preferable to use a 80 - 120 mm wide rolled multi-layer heat insulation layer 13 and wrap it in a semi-overlapping form. During the wrapping process, ensure that the heat insulation layer 13 is flat and without wrinkles, and each circle covers 50% ± 5% of the width of the previous circle. The starting wrapping angle forms an angle of 22.5° - 45° with the circumferential direction of the inner cylinder body 11, which can effectively reduce the possibility of the insulation layer being wound loosely.

[0089] In some embodiments, after baking the heat insulation layer 13 and connecting it to the outside of the cooling member 12, it includes: punching a plurality of evacuation holes in the heat insulation layer 13.

[0090] That is, after the heat insulation layer 13 is set up, stainless steel needles with a diameter of 2 - 3 mm can be used to punch evacuation holes in the heat insulation layer 13. The depth of the evacuation holes reaches the bottom layer of the heat insulation layer 13, and the hole pitch is 180 mm - 240 mm. The evacuation holes can effectively discharge the gas inside the heat insulation layer 13, thereby improving the vacuum degree between the inner cylinder body 11 and the outer cylinder body 2, and making the effect of reducing heat transfer better.

[0091] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0092] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A cable insulation structure, characterized in that, Comprising: A cable installation body, in which a cable is threaded; An inner cylinder assembly, which is sleeved outside the cable installation body, and a first heat insulation cavity is formed between the inner cylinder assembly and the cable installation body; An outer cylinder body, which is sleeved outside the inner cylinder assembly, a vacuum heat insulation cavity is formed between the outer cylinder body and the inner cylinder assembly, and the temperature zones corresponding to the cable installation body, the inner cylinder assembly and the outer cylinder body increase in sequence.

2. The cable insulation structure according to claim 1, characterized in that, The cable installation body includes a support body and support feet, the support body is installed with the cable, one end of the support feet is connected to the support body, and the other end is connected to the inner wall of the inner cylinder assembly.

3. The cable thermal insulation structure according to claim 2, characterized in that, A heat insulation pad is provided between the support body and the support feet.

4. The cable thermal insulation structure according to claim 2, wherein, The support body is provided with a heat insulation ring, and the cable is threaded through the heat insulation ring to be supported on the cable installation body.

5. The cable thermal insulation structure according to claim 1, characterized in that, The inner cylinder assembly includes an inner cylinder body and a cooling member, the cooling member is provided on the outer peripheral wall of the inner cylinder body, and a cooling medium is provided in the cooling member.

6. The cable insulation structure according to claim 5, characterized in that, The inner cylinder assembly further includes a heat insulation layer, and the heat insulation layer is provided outside the cooling member.

7. The cable thermal insulation structure according to claim 6, characterized in that, The heat insulation layer includes at least multiple layers of composite heat insulation layers, each layer of the composite heat insulation layer includes a heat insulation sub-layer and a reflection sub-layer, the multiple layers of composite heat insulation layers are distributed radially from the inner cylinder body to the outer cylinder body, and the reflection sub-layer includes a reflection surface, and the reflection surface faces the outer cylinder body.

8. The cable thermal insulation structure according to claim 7, wherein, The heat insulation layer further includes a first heat insulation layer, a second heat insulation layer and a fastening layer, the first heat insulation layer and the second heat insulation layer are respectively located on both sides of the multiple layers of composite heat insulation layers, the thermal conductivity of the first heat insulation layer and the second heat insulation layer is lower than that of the composite heat insulation layer, the first heat insulation layer is connected to the inner cylinder body and the second heat insulation layer faces the outer cylinder body, and the fastening layer is provided outside the second heat insulation layer.

9. The cable thermal insulation structure according to claim 1, characterized in that, A first support structure is further provided between the inner cylinder assembly and the outer cylinder body, the first support structure includes a first support portion, a second support portion and a first heat insulation plate, the first support portion is connected to the inner cylinder assembly and the second support portion is connected to the outer cylinder body, and the first heat insulation plate is connected between the first support portion and the second support portion.

10. The cable thermal insulation structure according to claim 9, characterized in that, The first support portion, the second support portion and the first heat insulation plate are connected by a connection component, and a heat insulation bushing is provided on the part of the connection component that penetrates into the first support portion, the second support portion and the first heat insulation plate.

11. The cable insulation structure according to claim 10, wherein The contact surface between the first heat insulation plate and the first support portion is multiple, and the contact surface with the second support portion is multiple.

12. The cable thermal insulation structure according to claim 1, characterized in that, It further includes a gravity support structure, the gravity support structure includes a first connection portion, a second connection portion and a support portion distributed vertically, the first connection portion is connected to the inner cylinder assembly, the second connection portion is connected to the outer cylinder body, and a second heat insulation plate is provided between the first connection portion and the second connection portion.

13. The cable thermal insulation structure according to claim 12, characterized in that, The contact surface between the second heat insulation plate and the first connection portion is multiple, and the contact surface between the second heat insulation plate and the second connection portion is multiple.

14. The cable insulation structure according to claim 12, wherein, The outer cylinder includes a plurality of first cylinder segments and a plurality of second cylinder segments arranged along the axial direction, the plurality of first cylinder segments are spaced apart along the axial direction, and the bottom of each first cylinder segment is connected to the gravity support structure, and a second cylinder segment is connected between adjacent first cylinder segments, and the second cylinder segment is formed by splicing two semi-arc cylinder segments.

15. The cable insulation structure according to claim 1, wherein, The outer cylinder is further provided with a vacuum extraction port and a vacuum gauge. The vacuum gauge measures the vacuum degree of the vacuum insulation cavity, and the vacuum extraction port is used for vacuuming.

16. A manufacturing method of a cable heat insulation structure, for manufacturing the cable heat insulation structure according to any one of claims 1-15, characterized in that, The following steps are involved: Pass the cable through the cable installation body; A cable installation body through which a cable is passed is installed in the inner cylinder assembly; The outer cylinder is connected to the outer periphery of the inner cylinder assembly to form a vacuum insulation chamber.

17. The manufacturing method of the cable thermal insulation structure according to claim 16, characterized in that, After the cable installation body with the cable installed on the inner wall of the inner cylinder assembly is installed, the method further includes: installing a first support portion of a first support structure on the outer wall of the inner cylinder assembly, and installing a second support portion of the first support structure on the inner wall of the outer cylinder.

18. The manufacturing method of the cable heat insulation structure according to claim 16, characterized in that, The method of connecting the outer cylinder to the outer periphery of the inner cylinder assembly to form a vacuum insulation chamber includes: Installing the inner cylinder assembly into a plurality of axially distributed first cylinder segments of the outer cylinder; Connecting the first support portion of the inner barrel assembly to the second support portion of the first barrel segment; The second barrel segments are connected between adjacent first barrel segments.

19. The manufacturing method of the cable thermal insulation structure according to claim 18, characterized in that, Before connecting the second barrel segments between adjacent first barrel segments, the method further includes: After the gravity support structure is connected to the outer wall of the first barrel segment, the gravity support structure is connected to the outer wall of the inner barrel assembly.

20. The manufacturing method of the cable thermal insulation structure according to claim 17, characterized in that, Before the outer cylinder is connected to the outer periphery of the inner cylinder assembly to form the vacuum insulation chamber, the method further includes: A cooling member is connected to the outer periphery of the inner cylinder body; The surface of the inner cylinder body is pickled, passivated, cleaned and baked; The insulation is baked on and attached to the exterior of the cooling element.

21. The manufacturing method of the cable thermal insulation structure according to claim 20, characterized in that, After the heat insulating layer is baked and connected to the outside of the cooling element, the method includes: piercing a plurality of vacuum holes in the heat insulating layer.

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