A heat-insulating structure and method for a heat-insulating joint of a rigid overhead finished heat-insulating pipeline

Abstract

The present invention discloses a heat insulation structure and method for a rigid overhead finished heat insulation pipeline joint, belonging to the technical field of pipeline heat insulation. The structure includes a working pipe, a soft heat insulation layer, a rigid spliced heat insulation layer, a dislocation step structure, a polyurethane heat insulation layer, a mortise and tenon assembly, a traction cloth, an inner heat insulation layer for the interface, a traction heat insulation layer for the interface, an outer heat insulation layer for the interface, an outer protective layer, a rigid fixed heat insulation layer, a rigid traction heat insulation layer, and a partial pressing and fixing device. By designing the structure of the heat insulation ring at the interface and using the method of mortise and tenon interface plus heat insulation layer flipping and traction cloth, the present invention always divides the gaps generated by thermal expansion at the heat insulation interface of the working pipeline into multiple independent annular spaces, avoiding the direct transfer of the heat of the working pipe to the outside through natural convection of the air in the gaps, solving the problem of serious heat loss at the interface of the heat insulation pipe, improving the heat insulation performance of the pipeline, and having a good market prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline insulation, and in particular relates to a rigid overhead finished product insulation pipeline joint insulation structure and method. Background Art

[0002] As clean production becomes more and more stringent and the society pays more attention to environmental protection, small coal-fired boilers used for regional heating will be gradually dismantled, and the required heat energy will be centrally supplied by large power plants using long-distance heat transmission networks. The heating radius of the heat transmission network continues to increase, and the loss of pipeline insulation and heat dissipation has become a key factor restricting the economic efficiency of heating pipelines. As the key core investment equipment of the thermal system, how to improve the thermal insulation effect of thermal pipelines and reduce the heat loss of the insulation structure is crucial to the economic efficiency of the thermal system.

[0003] The traditional way of connecting insulated pipes is to coat the interface of the finished pipe with a soft insulation layer, a calcium silicate layer, a polyurethane layer, etc. in sequence without passing steam through the pipe, and fully fill the gap between the steel pipe and the casing. During operation, high-temperature steam needs to be passed through the pipe. Due to the different thermal expansion coefficients of the working pipe and each insulation layer, displacement will occur between the insulation layer and the working pipe, resulting in a gap at the interface of the insulation pipe, so that the working pipe is connected to the outside air to form natural convection. When the gaps of each layer are connected, there will be more serious natural convection at the interface, the heat loss at the interface will be greatly increased, the insulation performance will decrease, and the efficiency of the entire heating network will also decrease. In the existing pipeline system, existing pipelines use the method of laying insulation layers in sections to form steps and staggering the gaps in the insulation layers to limit natural convection, but this method fails to prevent the gaps from being connected due to the thermal expansion of the pipeline, and does not reflect the ideal effect.

[0004] Therefore, from an economic point of view, solving the problem of severe natural convection at the interface of the insulation structure pipe during operation, which leads to large heat loss in the insulation pipe, can effectively improve the insulation performance of the insulation pipe and thus improve the economy, and has broad market prospects. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a hard overhead finished insulated pipe joint insulation structure and method.

[0006] The specific technical solutions adopted by the present invention are as follows:

[0007] In a first aspect, the present invention provides a thermal insulation structure for a rigid overhead finished thermal insulation pipeline joint, comprising two thermal insulation pipelines to be spliced; the thermal insulation pipeline includes a working pipe and a thermal insulation module covering the outer wall of the working pipe body, and the thermal insulation module includes a soft thermal insulation layer, several layers of rigid spliced thermal insulation layers and a polyurethane thermal insulation layer laid in sequence from inside to outside; both ends of the working pipe are located outside the thermal insulation module, and each layer of thermal insulation layer at the end forms a staggered step structure ascending from inside to outside; the splicing ends of the two thermal insulation pipelines together form an interface section; the ends of the two working pipes located in the interface section are connected by welding, and an interface inner thermal insulation layer with the same thickness as the soft thermal insulation layer and fitting with the innermost layer of the staggered step structure is laid on the outer wall; an interface traction thermal insulation layer fitting with the middle layers of the staggered step structure is laid on the outer wall of the interface inner thermal insulation layer; the interface traction thermal insulation layer is a stepped multi-layer structure, and the number of its layers and the thickness of each layer are the same as those of the rigid spliced thermal insulation layer; the interface traction thermal insulation layer includes a rigid fixed thermal insulation layer and a rigid traction thermal insulation layer, and the rigid traction thermal insulation layer includes two rigid traction thermal insulation sub-layers arranged axially and fittingly; an interface outer thermal insulation layer with the same thickness as the polyurethane thermal insulation layer and fitting with the outermost layer of the staggered step structure is laid on the outer wall of the interface traction thermal insulation layer;

[0008] Tenon and mortise components are respectively provided on the outer wall surfaces of two adjacent rigid spliced thermal insulation layers located in the innermost layer and near the interface section, and tenon and mortise components are respectively provided on the outer wall surfaces of the two rigid traction thermal insulation sub-layers; traction cloths are respectively arranged on each thermal insulation pipeline in the same winding manner; the head end of the traction cloth is clamped and fixed by the tenon and mortise component on the rigid spliced thermal insulation layer, then is laid on the inner side of the adjacent rigid traction thermal insulation sub-layer in a fitting manner, then passes through the gap between the two rigid traction thermal insulation sub-layers, is turned over and laid on the outer side of a part of the same rigid traction thermal insulation sub-layer in a fitting manner, and finally the tail end is clamped and fixed by the tenon and mortise component on this rigid traction thermal insulation sub-layer;

[0009] An outer protective layer capable of completely covering it is further provided on the outer wall of the interface outer thermal insulation layer, and the outer protective layer includes a waterproof sealing sleeve and a color steel plate outer protective layer; both ends of the waterproof sealing sleeve are respectively fixed on the polyurethane thermal insulation layers located on the axial two sides of the interface outer thermal insulation layer through waterproof sealant, and the middle part has a foldable and telescopic pleat, and the outer wall is covered with a color steel plate outer protective layer.

[0010] Preferably, the number of layers of the interface traction thermal insulation layer is two or three; when the number of layers of the interface traction thermal insulation layer is two, the rigid fixed thermal insulation layer is located on the inner side and the rigid traction thermal insulation layer is located on the outer side; when the number of layers of the interface traction thermal insulation layer is three, the rigid traction thermal insulation layer is the middle layer, and rigid fixed thermal insulation layers are respectively provided on the inner and outer wall surfaces.

[0011] Preferably, both the rigid fixed thermal insulation layer and the rigid traction thermal insulation layer are formed by splicing two semi-cylindrical structures; the axial lengths of the two rigid traction thermal insulation sub-layers are the same.

[0012] Preferably, the natural lengths of the inner insulation layer and the outer insulation layer of the interface are 1.0 to 1.2 times the length of the weld, and the installation length is the axial length of the interface section.

[0013] Preferably, the width of each step in the staggered step structure is 1.5 to 2.0 times the theoretical thermal expansion length of the working pipe; the length of the outer protective layer is 1.5 to 2.0 times the theoretical thermal expansion length at the interface of the working pipe.

[0014] Preferably, the coefficient of thermal expansion of the traction cloth is not higher than that of the rigid spliced insulation layer, and a reflective layer is coated on the side of the traction cloth facing the working pipe.

[0015] Preferably, the soft insulation layer is made of aerogel, glass fiber or aluminosilicate rock wool materials.

[0016] Preferably, in the rigid spliced insulation layer, the number of splicing blocks in the circumferential direction of each layer is 2 to 6, and the distance of the flat joint in the axial direction from the edge of each block is not less than 1 / 3 of the length of the splicing block.

[0017] Preferably, the mortise and tenon assembly includes a tenon interface and a pressing joint, and its axial length is 1 / 2 to 2 / 3 of the axial length of the splicing block in the layer where it is located.

[0018] In a second aspect, the present invention provides a joint heat preservation method using the joint heat preservation structure of any one of the rigid overhead finished heat preservation pipeline joints in the first aspect, specifically as follows:

[0019] Lay the soft insulation layer, several layers of rigid spliced insulation layers and polyurethane insulation layer on the outer wall surface of the working pipe from the inside to the outside in sequence, and form a staggered step structure rising from the inside to the outside at both ends of the working pipe; clamp and fix one end of the traction cloth through the mortise and tenon assembly on the rigid spliced insulation layer; connect the ends of the two working pipes by welding, and complete the strength test after welding and the anti-corrosion of the weld at the interface.

[0020] Lay the inner interface insulation layer, the interface traction insulation layer and the outer interface insulation layer on the interface section of the two working pipes from the inside to the outside in sequence, and all three insulation layers are tightly connected to the main body insulation module of the working pipe through the staggered step structure under cold conditions; the traction cloth is wound around the adjacent rigid traction insulation sub-layer, and the end is clamped and fixed through the mortise and tenon assembly on the rigid traction insulation sub-layer.

[0021] After the insulation module of the interface section is arranged, lay a waterproof seal on the outer wall of the outer interface insulation layer, and fix the waterproof seal on the polyurethane insulation layers on both axial sides of the outer interface insulation layer with sealant to completely seal the insulation module of the interface section; then, cover a color steel plate outer protective layer on the outer wall of the waterproof seal for protection.

[0022] The present invention has the following beneficial effects compared with the prior art:

[0023] (1) By utilizing the difference in the coefficient of thermal expansion between the flipping traction cloth and the working pipeline, and designing a mortise and tenon structure for fixation on the solid heat-insulating material, the present invention realizes that during the thermal expansion and elongation process of the working pipe, the joints and the intermediate solid heat-insulating layer are relatively fixed, while the other heat-insulating layers can move freely. Thus, the staggered joint effect of the gaps between the heat-insulating layers of each joint is effectively ensured, the purpose of avoiding straight-seam heat dissipation is achieved, the heat-insulating performance at the interface of the heat-insulating pipe is enhanced, and the overall thermal economy of the heat-insulating pipeline is improved.

[0024] (2) When installing the structure of the present invention, there is no need to use a hot-state interface, and a cold-state interface can be used, which makes on-site installation more convenient. Description of the Drawings

[0025] Figure 1 is a schematic cross-sectional view of a heat-insulating structure for the joint of a rigid overhead finished heat-insulating pipeline in a cold-state working condition of the present invention;

[0026] Figure 2 is a schematic cross-sectional view of a heat-insulating structure for the joint of a rigid overhead finished heat-insulating pipeline in a hot-state working condition of the present invention;

[0027] Figure 3 is a schematic structural view of the interface section of the present invention;

[0028] Figure 4 is a schematic structural view of the mortise and tenon assembly of the present invention;

[0029] Figure 5 (a) of is a schematic cross-sectional view of the two-layer semi-cylindrical interface traction heat-insulating layer of the present invention; Figure 5 (b) of is a schematic cross-sectional view of the three-layer semi-cylindrical interface traction heat-insulating layer of the present invention;

[0030] Figure 6 is a detailed schematic view of the outer protective layer of the present invention.

[0031] In the figures: working pipe 1, soft heat-insulating layer 2, rigid spliced heat-insulating layer 3, dislocation step structure 4, polyurethane heat-insulating layer 5, mortise and tenon assembly 6, traction cloth 7, interface section 8, inner heat-insulating layer of the interface 9, interface traction heat-insulating layer 10, outer heat-insulating layer of the interface 11, seam of the inner heat-insulating layer of the interface 12, regulating seam of the heat-insulating layer of the interface 13, seam of the outer heat-insulating layer of the interface 14, outer protective layer 15, rigid fixed heat-insulating layer 16, rigid traction heat-insulating layer 17, waterproof sealing sleeve 18, fold 19, color steel plate outer protective layer 20. Detailed Embodiments

[0032] The present invention will be further described and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly without conflict with each other.

[0033] It should be noted that, in the present invention, the "outer wall" mentioned refers to the side radially outward along the heat-insulating pipeline unless otherwise specified. The "end side" mentioned in the present invention refers to the end pointed along the axial direction of the heat-insulating pipeline unless otherwise specified. The "layer" mentioned in the present invention refers to an annular structure unless otherwise specified.

[0034] As Figure 1 shown, a heat-insulating structure for a rigid overhead finished heat-insulating pipeline joint provided by the present invention mainly includes two heat-insulating pipelines to be spliced, and the two heat-insulating pipelines located in the interface section 8 should be coaxially arranged. The heat-insulating pipeline includes a working pipe 1 and a heat-insulating module. Among them, the heat-insulating module is coated on the main body outer wall of the working pipe 1. The heat-insulating module includes a soft heat-insulating layer 2, several layers of rigid spliced heat-insulating layers 3 and a polyurethane heat-insulating layer 5 laid from the inside to the outside. Each layer of heat-insulating layer is an annular structure and is sleeved in sequence. The two end portions of the working pipe 1 protrude from the heat-insulating module, that is, they are both located outside the heat-insulating module; and each layer of heat-insulating layer at the end forms a staggered step structure 4 ascending from the inside to the outside, so as to facilitate the assembly of the heat-insulating module at the connection. As Figure 3 shown, the splicing ends of the two heat-insulating pipelines together form an interface section 8.

[0035] In this embodiment, the soft heat-insulating layer 2 is preferably made of materials such as aerogel, glass fiber or aluminum silicate rock wool. In the rigid spliced heat-insulating layer 3, the number of splicing blocks in the circumferential direction of each layer is 2 to 6, and the distance of the flat joint seam in the axial direction from the edge of each block is not less than 1 / 3 of the length of the splicing block.

[0036] The present invention mainly improves the heat-insulating module of the interface section 8 and improves the heat-insulating and sealing performance of the interface section, specifically as follows:

[0037] The adjacent ends of the two working pipes 1 located in the interface section 8 are connected by welding to form a weld seam. An interface inner heat-insulating layer 9 is laid on the outer walls of the two working pipes 1 located in the interface section 8. The interface inner heat-insulating layer 9 has the same thickness as the soft heat-insulating layer 2 and fits with the innermost layer of the staggered step structure 4. An interface traction heat-insulating layer 10 is laid on the outer wall of the interface inner heat-insulating layer 9. The interface traction heat-insulating layer 10 is a stepped multi-layer structure and fits with the middle layers of the staggered step structure 4. The number of layers of the interface traction heat-insulating layer 10 is the same as the total number of layers of the rigid spliced heat-insulating layer 3, and the thickness of each layer is the same as that of a single layer of the rigid spliced heat-insulating layer 3. The interface traction heat-insulating layer 10 includes a rigid fixed heat-insulating layer 16 and a rigid traction heat-insulating layer 17. The rigid traction heat-insulating layer 17 includes two rigid traction heat-insulating sub-layers arranged axially in contact. In this embodiment, as Figure 5As shown in the figure, the number of layers of the interface traction insulation layer 10 can be two or three: when the number of layers of the interface traction insulation layer 10 is two, the rigid fixed insulation layer 16 is located on the inner side and the rigid traction insulation layer 17 is located on the outer side; when the number of layers of the interface traction insulation layer 10 is three, the rigid traction insulation layer 17 is the middle layer, and the rigid fixed insulation layers 16 are respectively provided on the inner and outer side walls. An interface outer insulation layer 11 is laid on the outer wall of the interface traction insulation layer 10. The interface outer insulation layer 11 has the same thickness as the polyurethane insulation layer 5 and fits with the outermost layer of the staggered step structure 4. That is to say, the insulation pipe interface is overlapped through the staggered step structure 4 and the interface inner insulation layer 9, the interface traction insulation layer 10 and the interface outer insulation layer 11 are laid in sequence.

[0038] In this embodiment, both the rigid fixed insulation layer 16 and the rigid traction insulation layer 17 are formed by splicing two semi-cylindrical structures. The axial lengths of the two rigid traction sub-layers are preferably the same. It is optimal that the interface inner insulation layer 9 and the interface outer insulation layer 11 are in one piece. Its natural length is 1.0 - 1.2 times the weld length, and the installation length is the axial length of the interface section 8. The staggered step structure 4 is a convex structure, and the width of each step is 1.5 - 2.0 times the theoretical thermal expansion length of the working pipe 1.

[0039] Mortise and tenon assemblies 6 are respectively provided on the outer wall surfaces of two rigid splicing insulation layers 3 that are adjacent to the interface section 8 and located in the innermost layer, and mortise and tenon assemblies 6 are respectively provided on the outer wall surfaces of the two rigid traction sub-layers. That is to say, for one end of each heat-insulating pipeline, there are two mortise and tenon assemblies 6 in total. Traction cloths 7 are respectively arranged on each heat-insulating pipeline in the same winding manner. The winding manner is as follows:

[0040] The head end of the traction cloth 7 is clamped and fixed through the mortise and tenon assembly 6 on the rigid splicing insulation layer 3, then is laid and attached to the inner side of the adjacent rigid traction sub-layer, then passes through the gap between the two rigid traction sub-layers, is turned over and laid and attached to the outer side of a part of the same rigid traction sub-layer, and finally the tail end is clamped and fixed through the mortise and tenon assembly 6 on this rigid traction sub-layer. That is to say, the traction cloth 7 is laid between the rigid fixed insulation layer 16 and the rigid traction insulation layer 17 of the interface traction insulation layer 10, and is fixed on the rigid traction insulation layer 17 through the mortise and tenon assembly 6 after being turned over.

[0041] In this embodiment, the thermal expansion coefficient of the traction cloth 7 should not be higher than that of the rigid splicing insulation layer 3, and a reflective layer is coated on the side of the traction cloth 7 facing the working pipe 1. As Figure 4 shown, the mortise and tenon assembly 6 mainly includes a mortise interface and a pressing joint. The mortise interface is opened on the corresponding heat-insulating (sub-) layer, and the pressing joint can cooperate with the mortise interface to achieve mortise and tenon connection. The axial lengths of the mortise interface and the pressing joint are 1 / 2 - 2 / 3 of the axial length of the splicing block of the corresponding heat-insulating (sub-) layer.

[0042] As Figure 6 shown, an outer protective layer 15 capable of completely covering the outer wall of the interface external thermal insulation layer 11 is provided on the outer wall of the interface external thermal insulation layer 11. The outer protective layer 15 includes a waterproof sealing sleeve 18 and a color steel plate outer protective layer 20. Both ends of the waterproof sealing sleeve 18 are respectively fixed on the polyurethane thermal insulation layers 5 on the axial two sides of the interface external thermal insulation layer 11 through waterproof sealant. The middle part has a retractable fold 19, and the outer wall is covered with a color steel plate outer protective layer 20.

[0043] In this embodiment, the length of the outer protective layer 15 is preferably 1.5 - 2.0 times the theoretical thermal expansion length at the interface of the working pipe 1 (i.e., the interface section 8).

[0044] The joint thermal insulation method using the above-mentioned rigid overhead finished thermal insulation pipeline joint thermal insulation structure is as follows:

[0045] The soft thermal insulation layer 2, several layers of rigid spliced thermal insulation layers 3 and polyurethane thermal insulation layers 5 are sequentially laid on the outer wall surface of the working pipe 1 from the inside to the outside, and a staggered step structure 4 ascending from the inside to the outside is formed at both ends of the working pipe 1. One end of the traction cloth 7 is clamped and fixed through the mortise and tenon assembly 6 on the rigid spliced thermal insulation layer 3. The ends of the two working pipes 1 are connected by welding, and the strength test after welding and the anti-corrosion of the weld at the interface are completed.

[0046] At the interface section 8 of the two working pipes 1, an interface internal thermal insulation layer 9, an interface traction thermal insulation layer 10 and an interface external thermal insulation layer 11 are sequentially laid from the inside to the outside, and the three thermal insulation layers are tightly connected to the main body thermal insulation module of the working pipe 1 under cold conditions through the staggered step structure 4. The traction cloth 7 is wound around the adjacent rigid traction thermal insulation sub-layer, and the end is clamped and fixed through the mortise and tenon assembly 6 on the rigid traction thermal insulation sub-layer. That is to say, the traction cloth 7 is installed between the rigid fixed thermal insulation layer 16 and the rigid traction thermal insulation layer 17 of the interface traction thermal insulation layer 10, and after being turned over between the two rigid traction thermal insulation layers 17 at the interface, it is pressed and fixed through the mortise and tenon assembly 6 on the rigid traction thermal insulation layer 17.

[0047] After the thermal insulation module at the interface section 8 is arranged, waterproof measures must be taken. First, use a reflective layer and a steel strip to fix the thermal insulation ring. A waterproof sealing sleeve 18 is arranged on the outer wall of the interface external thermal insulation layer 11. The waterproof sealing sleeve 18 is fixed on the polyurethane thermal insulation layers 5 on the axial two sides of the interface external thermal insulation layer 11 using high-strength waterproof sealant to completely seal the thermal insulation module at the interface section 8. The sealing sleeve is soft and can be retracted through the fold 19. Finally, a color steel plate outer protective layer 20 is sleeved on the outer wall of the waterproof sealing sleeve 18 for protection.

[0048] When the working pipe 1 is working, all gaps are in a normal closed state under cold conditions. Under hot conditions, as Figure 2As shown, due to the inconsistent thermal expansion coefficients of the working pipe and the thermal insulation material, the elongation of the working pipe will be greater than that of the thermal insulation layer, resulting in an interface inner thermal insulation layer seam 12 formed between both ends of the inner thermal insulation layer 9 in the interface and the soft thermal insulation layer 2, and an interface outer thermal insulation layer seam 14 formed between both ends of the outer thermal insulation layer 11 in the interface and the polyurethane thermal insulation layer 5. Interface thermal insulation layer adjustment seams 13 are respectively formed between the rigid fixed thermal insulation layer 16 and the same-layer rigid spliced thermal insulation layer 3, and between the two rigid traction thermal insulation layers 17. Under the fixing action of the traction cloth 7, the interface thermal insulation layer adjustment seam 13 of the rigid traction thermal insulation layer 17 will appear in the middle instead of at both ends of the working pipe thermal insulation layer, forming a staggered joint effect, avoiding the risk of through seams that may be generated if all leakage seams appear at both ends, thereby effectively reducing the heat leakage effect of natural convection of the seams and improving the thermal insulation effect and reliability at the interface.

[0049] The present invention controls the dimensions of the thermal insulation ring stepped structure and uses the mortise and tenon assembly 6 and the traction cloth 7 to always divide the voids generated by thermal expansion (i.e., the interface inner thermal insulation layer seam 12, the interface thermal insulation layer adjustment seam 13, and the interface outer thermal insulation layer seam 14) into multiple independent annular spaces, avoiding the heat of the working pipe 1 from being directly transferred to the outer protective layer 15 through natural convection of the air in the voids, reducing the natural convection heat transfer and radiation heat transfer caused by the voids, and improving the thermal insulation performance of the pipeline interface.

[0050] The above-described embodiments are only a preferred solution of the present invention, but they are not intended to limit the present invention. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A thermal insulation structure for a rigid overhead finished thermal insulation pipeline joint, characterized in that, Including two heat-insulating pipes to be spliced; the heat-insulating pipe includes a working pipe (1) and a heat-insulating module covering the outer wall of the main body of the working pipe (1), and the heat-insulating module includes a soft heat-insulating layer (2), several layers of hard spliced heat-insulating layers (3) and a polyurethane heat-insulating layer (5) laid in sequence from inside to outside; both ends of the working pipe (1) are located outside the heat-insulating module, and each layer of heat-insulating layer at the end of the working pipe (1) jointly forms a stepped structure (4) ascending from inside to outside; the splicing ends of the two heat-insulating pipes jointly form an interface section (8); the ends of the two working pipes (1) located in the interface section (8) are connected by welding, and an interface inner heat-insulating layer (9) with the same thickness as the soft heat-insulating layer (2) and fitting with the innermost layer of the stepped structure (4) is laid on the outer wall of the working pipe (1); an interface traction heat-insulating layer (10) fitting with the middle layers of the stepped structure (4) is laid on the outer wall of the interface inner heat-insulating layer (9); the interface traction heat-insulating layer (10) is a stepped multi-layer structure, and the number of its layers and the thickness of each layer are the same as those of the hard spliced heat-insulating layer (3); the interface traction heat-insulating layer (10) includes a hard fixed heat-insulating layer (16) and a hard traction heat-insulating layer (17), and the hard traction heat-insulating layer (17) includes two hard traction heat-insulating sub-layers laid axially in contact; an interface outer heat-insulating layer (11) with the same thickness as the polyurethane heat-insulating layer (5) and fitting with the outermost layer of the stepped structure (4) is laid on the outer wall of the interface traction heat-insulating layer (10); Tenon and mortise components (6) are respectively arranged on the outer wall surfaces of two adjacent hard spliced heat-insulating layers (3) closest to the interface section (8) and on the outer wall surfaces of the two hard traction heat-insulating sub-layers; a traction cloth (7) is arranged on each heat-insulating pipe in the same winding manner; the head end of the traction cloth (7) is clamped and fixed by the tenon and mortise component (6) on the hard spliced heat-insulating layer (3), then laid in contact on the inner side of the adjacent hard traction heat-insulating sub-layer, then passes through the gap between the two hard traction heat-insulating sub-layers, is turned over and laid in contact on the outer side of a part of the same hard traction heat-insulating sub-layer, and finally the tail end is clamped and fixed by the tenon and mortise component (6) on this hard traction heat-insulating sub-layer; An outer protective layer (15) capable of completely covering it is further arranged on the outer wall of the interface outer heat-insulating layer (11), and the outer protective layer (15) includes a waterproof sealing sleeve (18) and a color steel plate outer protective layer (20); both ends of the waterproof sealing sleeve (18) are respectively fixed on the polyurethane heat-insulating layers (5) on the axial two sides of the interface outer heat-insulating layer (11) by waterproof sealant, the middle part has a fold (19) capable of stretching, and the outer wall is covered with a color steel plate outer protective layer (20); The coefficient of thermal expansion of the traction cloth (7) is not higher than that of the hard spliced heat-insulating layer (3), and a reflective layer is coated on the side of the traction cloth (7) facing the working pipe (1).

2. The thermal insulation structure of the rigid overhead finished thermal insulation pipeline joint according to claim 1, wherein The number of layers of the interface traction insulation layer (10) is two or three; when the number of layers of the interface traction insulation layer (10) is two, the rigid fixed insulation layer (16) is located on the inner side and the rigid traction insulation layer (17) is located on the outer side; when the number of layers of the interface traction insulation layer (10) is three, the rigid traction insulation layer (17) is the middle layer, and rigid fixed insulation layers (16) are respectively provided on the inner and outer side walls.

3. The thermal insulation structure of the rigid overhead finished thermal insulation pipeline joint according to claim 1, wherein, Both the rigid fixed insulation layer (16) and the rigid traction insulation layer (17) are formed by splicing two semi-cylindrical structures; the axial lengths of the two rigid traction sub-layers are the same.

4. A thermal insulation structure for a rigid overhead finished thermal insulation pipeline joint according to claim 1, characterized in that The natural lengths of the interface inner insulation layer (9) and the interface outer insulation layer (11) are 1.0 - 1.2 times the length of the weld, and the installation length is the axial length of the interface section (8).

5. The thermal insulation structure of the rigid overhead finished thermal insulation pipeline joint according to claim 1, characterized in that The staggered step structure (4) is a convex structure, the width of each step is 1 / 4 - 1 / 3 of the axial length of a single splicing block and not less than 1.5 - 2.0 times the theoretical thermal expansion length of the working pipe (1); the length of the outer protective layer (15) is 1.5 - 2.0 times the theoretical thermal expansion length at the interface of the working pipe (1).

6. The thermal insulation structure of a rigid overhead finished thermal insulation pipeline joint according to claim 1, characterized in that, The soft insulation layer (2) is made of materials such as aerogel, glass fiber or aluminosilicate rock wool.

7. A thermal insulation structure for a rigid overhead finished thermal insulation pipeline joint according to claim 1, characterized in that, In the rigid splicing insulation layer (3), the number of splicing blocks in the circumferential direction of each layer is 2 - 6, and the distance of the flat joint in the axial direction from the edge of each block is not less than 1 / 3 of the length of the splicing block.

8. The thermal insulation structure of the rigid overhead finished thermal insulation pipeline joint according to claim 1, wherein, The tenon and mortise component (6) includes a mortise interface and a pressing joint, and its axial length is 1 / 2 - 2 / 3 of the axial length of the splicing block in the layer where it is located.

9. A joint heat preservation method using the heat preservation structure of the rigid overhead finished heat preservation pipeline joint described in any one of claims 1 to 8, characterized in that, Specifically as follows: The soft insulation layer (2), several layers of rigid splicing insulation layers (3) and the polyurethane insulation layer (5) are sequentially laid on the outer wall of the working pipe (1) from the inside to the outside, and a staggered step structure (4) ascending from the inside to the outside is formed at both ends of the working pipe (1); one end of the traction cloth (7) is clamped and fixed through the tenon and mortise component (6) on the rigid splicing insulation layer (3); the ends of the two working pipes (1) are connected by welding, and the strength test after welding and the anti-corrosion of the weld at the interface are completed. At the interface section (8) of the two working pipes (1), the interface inner insulation layer (9), the interface traction insulation layer (10) and the interface outer insulation layer (11) are sequentially laid from the inside to the outside, and all three insulation layers are tightly connected to the main body insulation module of the working pipe (1) under cold conditions through the staggered step structure (4); the traction cloth (7) is wound around the adjacent rigid traction sub-layer, and the end is clamped and fixed through the tenon and mortise component (6) on this rigid traction sub-layer. After the insulation module of the interface section (8) is arranged, a waterproof seal (18) is arranged on the outer wall of the interface outer insulation layer (11), and the waterproof seal (18) is fixed on the polyurethane insulation layers (5) on the axial two sides of the interface outer insulation layer (11) using sealant to completely seal the insulation module of the interface section (8); then a color steel plate outer protection layer (20) is sleeved on the outer wall of the waterproof seal (18) for protection.

Images