Multi-layer heat insulation pipe for conveying high-temperature steam

Abstract

The utility model discloses a multi-layer heat insulation pipe for conveying high-temperature steam, which is applied to the field of high-temperature steam conveying and comprises an inner pipe, an outer pipe, an infrared radiation reflecting layer, a first heat insulation layer and a second heat insulation layer, the second heat insulation layer and the first heat insulation layer are distributed in a staggered mode, and when the multi-layer heat insulation pipe is used, the first heat insulation layer is formed by splicing two semicircular assemblies. The second heat insulation layer adopts the same structure, but is staggered with the joints of the first layer, and covers the splicing gaps of the first layer, so that heat needs to penetrate through more layers of materials, and double heat resistance is realized by prolonging the heat flow path and increasing the interface heat resistance; and then the outer protective layer resists mechanical shock, chemical corrosion and environmental aging.

Description

Technical Field

[0001] This utility model belongs to the field of high-temperature steam transportation technology, and specifically relates to a multi-layer heat-insulating pipe for transporting high-temperature steam. Background Technology

[0002] High-temperature steam transmission pipelines are key equipment in energy, chemical, and metallurgical fields. Their core function is to safely and efficiently transport high-temperature steam from the source to the heat-using terminal. Traditional steam pipelines mostly adopt a single-layer insulation structure, mainly using conventional insulation materials such as rock wool and glass wool.

[0003] The current announcement of Chinese utility model patent CN2682268Y discloses a multi-layered insulated pipe for conveying high-temperature steam. It consists of a steel pipe, a rust-proof layer, a high-strength insulation block, an air layer, an aluminum plate reflective layer, an inner porous insulation layer, an aluminum foil reflective layer, an outer porous insulation layer, a low-emissivity insulation layer, an outer protective layer, and a reserved welding section. It features simple construction, reasonable insulation structure, reduced total insulation thickness, good insulation effect, significant energy-saving and economic benefits, safe and reliable use, and long service life. It can be used for insulated pipelines for conveying high-temperature media.

[0004] Existing high-temperature steam insulation pipelines all use two semi-circular insulation cotton bundles for insulation. However, the joint between the two semi-circular insulation cotton bundles will form a seam, which is the weakest point of the insulation layer and affects the insulation effect. Utility Model Content

[0005] The purpose of this invention is to provide a multi-layered insulated pipe for conveying high-temperature steam, which solves the problem that existing high-temperature steam insulated conveying pipes all use two semi-circular insulation cotton bundles for insulation, but the splicing of the two semi-circular insulation cotton will form a seam, which is the weakest point of the insulation layer and affects the insulation effect.

[0006] The above-mentioned technical objective of this utility model is achieved through the following technical solution: a multi-layer heat-insulating pipe for conveying high-temperature steam, comprising an inner pipe and an outer pipe, wherein a microchannel is formed between the inner pipe and the outer pipe, and a support frame is fixedly installed on the outer pipe, wherein the number of support frames is several and arranged circumferentially, the cross-section of the support frame is hexagonal, an infrared radiation reflective layer is provided on the outer side of the support frame, a first heat insulation layer is provided on the infrared radiation reflective layer, the first heat insulation layer is composed of two semicircles, a second heat insulation layer is provided on the first heat insulation layer, the second heat insulation layer is composed of two semicircles, the second heat insulation layer and the first heat insulation layer are staggered, and a protective layer is provided on the outside of the second heat insulation layer.

[0007] The above technical solution involves setting up an inner pipe, an outer pipe, a support frame, an infrared radiation reflective layer, a first insulation layer, a second insulation layer, and a protective layer. The insulated pipe consists of an inner pipe and an outer pipe, forming a microchannel between them. The support frame is circumferentially distributed with a hexagonal cross-section to maintain the stability of the pipe structure. The infrared radiation reflective layer blocks heat radiation. The first insulation layer is composed of two semi-circular components spliced ​​together to form an initial thermal resistance barrier, blocking most of the direct conduction paths. The second insulation layer has the same structure but is staggered from the first layer, covering the splicing gaps of the first layer, forcing heat to penetrate more layers of material. This achieves dual heat insulation by extending the heat flow path and increasing the interface thermal resistance. Finally, the outer protective layer resists mechanical impact, chemical corrosion, and environmental aging.

[0008] Furthermore: a spiral groove is formed on the inner wall of the inner tube, and a number of high thermal conductivity graphite sheets are arranged inside the spiral groove.

[0009] By adopting the above technical solution, the spiral grooves and high thermal conductivity graphite sheets are set. The spiral grooves guide the high temperature steam to form a spiral flow, force the fluid to generate centrifugal motion, destroy the laminar boundary layer, enhance the convective heat transfer efficiency of the inner tube, and increase the contact area between the steam and the inner wall, thereby increasing the surface area base of heat exchange. The high thermal conductivity graphite sheets are evenly distributed along the spiral grooves, which quickly conduct the local high temperature of the inner wall along the axial direction, eliminate "hot spots" and homogenize the temperature field.

[0010] Furthermore, the microchannel is filled with a phase change material, which may be composed of a NaNO3-KNO3-LiNO3 eutectic salt.

[0011] By adopting the above technical solution, when high-temperature steam passes through the microchannel, the phase change material absorbs heat and melts, storing latent heat and accelerating thermal equilibrium. When the steam temperature fluctuates, the phase change material suppresses sudden temperature changes in the pipe wall through phase change, thereby reducing thermal stress.

[0012] Furthermore, the interior of the support frame is filled with low thermal conductivity aerogel particles, which may be SiO2 aerogel.

[0013] By adopting the above technical solution, the hexagonal cross-section has the highest structural stiffness-to-weight ratio when distributed circumferentially by setting the filling material inside the support frame. It can withstand the radial pressure of the inner and outer tubes, and avoid local stress concentration by filling with aerogel. The low elastic modulus of SiO2 aerogel allows the support frame to produce slight deformation when the temperature changes, which alleviates the mechanical stress caused by the difference in thermal expansion coefficients between the inner and outer tubes.

[0014] Furthermore, both the first and second insulation layers are made of insulation cotton.

[0015] By adopting the above technical solution, and by setting the materials of the first and second insulation layers, the fiber interwoven structure of the insulation cotton forms a large number of nanoscale pores, which can effectively block solid heat conduction.

[0016] Furthermore, both the inner and outer tubes are made of stainless steel.

[0017] By adopting the above technical solution, and by setting the materials of the inner and outer pipes, the high strength of stainless steel can withstand the radial pressure of high-pressure steam, preventing the pipe body from deforming, and the toughness of stainless steel can absorb the stress generated by the thermal expansion and contraction of the pipeline or external vibration, thus extending the service life.

[0018] Furthermore, the width of the microchannel is 4-6 mm.

[0019] By adopting the above technical solution, the width of the microchannel is set to 4-6mm, which can accommodate a sufficient amount of phase change material to meet the transient heat load requirements of high-temperature steam transportation. The matching of the microchannel width with the latent heat of fusion of the phase change material ensures that the phase change material can be completely melted / solidified when the steam temperature fluctuates, avoiding the heat capacity decay caused by partial phase change.

[0020] Furthermore, the infrared radiation reflective layer may be made of aluminum and have a polished surface.

[0021] By adopting the above technical solution and setting the material of the reflective layer, aluminum can achieve a reflectivity of 90%-95% in the infrared band, which can better reflect the thermal radiation of high-temperature steam.

[0022] In summary, this utility model has the following beneficial effects:

[0023] The insulated pipe is composed of an inner pipe, an outer pipe, a support frame, an infrared radiation reflective layer, a first insulation layer, a second insulation layer, and a protective layer. The inner and outer pipes form a microchannel between them. The support frame is circumferentially distributed with a hexagonal cross-section to maintain the stability of the pipe structure. The infrared radiation reflective layer blocks heat radiation. The first insulation layer is composed of two semi-circular components spliced ​​together to form an initial thermal resistance barrier, blocking most of the direct conduction path. The second insulation layer adopts the same structure but is staggered from the first layer, covering the splicing gap of the first layer, forcing heat to penetrate more layers of material. This achieves dual heat insulation by extending the heat flow path and increasing the interface thermal resistance. Finally, the outer protective layer resists mechanical impact, chemical corrosion, and environmental aging.

[0024] By setting the filling material in the microchannel, when high-temperature steam passes through, the phase change material absorbs heat and melts, storing latent heat and accelerating thermal equilibrium. When the steam temperature fluctuates, the phase change material suppresses sudden temperature changes in the pipe wall through phase change, reducing thermal stress.

[0025] Based on the above improvements, the overall technical effect achieved by this device is that by staggering the two insulation layers, the seams of the insulation layers can be covered, forcing heat to penetrate more layers of material. This achieves dual heat insulation by extending the heat flow path and increasing the interface thermal resistance, and further improves the insulation effect through multi-layer insulation. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0027] Figure 2 This is the left view of this utility model;

[0028] Figure 3 This is the utility model Figure 2 3D cross-sectional view at point AA;

[0029] Figure 4 This is a schematic diagram of the microchannel, support frame, and infrared radiation reflective layer of this utility model;

[0030] Figure 5 This is a schematic diagram of the structure of the first and second heat insulation layers of this utility model;

[0031] Figure 6 This is the utility model Figure 3 Enlarged view of point A in the middle.

[0032] In the diagram, 1 is the inner tube; 2 is the outer tube; 3 is the microchannel; 4 is the support frame; 5 is the infrared radiation reflective layer; 6 is the first heat insulation layer; 7 is the second heat insulation layer; 8 is the protective layer; 9 is the spiral groove; and 10 is the high thermal conductivity graphite sheet. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings.

[0034] Example:

[0035] Please see Figures 1-6 The present invention provides a technical solution: a multi-layered heat-insulating pipe for conveying high-temperature steam, comprising an inner pipe 1 and an outer pipe 2, with a microchannel 3 formed between the inner pipe 1 and the outer pipe 2, and a support frame 4 fixedly installed on the outer pipe 2. The support frame 4 is a plurality of supports arranged in a circle, and the cross-section of the support frame 4 is hexagonal. An infrared radiation reflective layer 5 is provided on the outside of the support frame 4, and a first heat insulation layer 6 is provided on the infrared radiation reflective layer 5. The first heat insulation layer 6 is composed of two semicircles. A second heat insulation layer 7 is provided on the first heat insulation layer 6, and the second heat insulation layer 7 is composed of two semicircles. The second heat insulation layer 7 and the first heat insulation layer 6 are staggered. A protective layer 8 is provided on the outside of the second heat insulation layer 7.

[0036] The insulated pipe consists of an inner pipe 1, an outer pipe 2, a support frame 4, an infrared radiation reflective layer 5, a first insulation layer 6, a second insulation layer 7, and a protective layer 8. The inner pipe 1 and the outer pipe 2 form a microchannel 3 between them. Meanwhile, the support frame 4 is circumferentially distributed with a hexagonal cross-section to maintain the stability of the pipe structure. The infrared radiation reflective layer 5 can block heat radiation. The first insulation layer 6 is spliced ​​from two semi-circular components to form an initial thermal resistance barrier, blocking most of the direct conduction path. The second insulation layer 7 adopts the same structure but is staggered from the first layer's seam, covering the splicing gap of the first layer, forcing heat to penetrate more layers of material. By extending the heat flow path and increasing the interface thermal resistance, dual heat insulation is achieved. Finally, the outer protective layer 8 resists mechanical impact, chemical corrosion, and environmental aging.

[0037] refer to Figure 6 The inner wall of the inner tube 1 is provided with a spiral groove 9, and a number of high thermal conductivity graphite sheets 10 are arranged inside the spiral groove 9. The high thermal conductivity graphite sheets 10 are evenly arranged. By setting the spiral groove 9 and the high thermal conductivity graphite sheets 10, the spiral groove 9 guides the high temperature steam to form a spiral flow, forces the fluid to generate centrifugal motion, destroys the laminar boundary layer, enhances the convective heat transfer efficiency of the inner tube 1, and increases the contact area between the steam and the inner wall, thereby increasing the surface area of ​​heat exchange. The high thermal conductivity graphite sheets 10 are evenly distributed along the spiral groove 9, which quickly conducts the local high temperature of the inner wall along the axial direction, eliminates "hot spots" and homogenizes the temperature field.

[0038] refer to Figure 4 The microchannel 3 is filled with a phase change material, which can be composed of NaNO3-KNO3-LiNO3 eutectic salt. By setting the filling material in the microchannel 3, when high-temperature steam passes through, the phase change material absorbs heat and melts, stores latent heat, and accelerates thermal equilibrium. When the steam temperature fluctuates, the phase change material suppresses the sudden change in pipe wall temperature through phase change and reduces thermal stress.

[0039] refer to Figure 4 The support frame 4 is filled with low thermal conductivity aerogel particles, which can be SiO2 aerogel. By setting the filling material inside the support frame 4, the hexagonal cross section has the highest structural stiffness-to-weight ratio when distributed circumferentially. It can withstand the radial pressure of the inner and outer tubes 2, and avoid local stress concentration through aerogel filling. The low elastic modulus of SiO2 aerogel allows the support frame 4 to produce small deformations when the temperature changes, which alleviates the mechanical stress caused by the difference in thermal expansion coefficients between the inner tube 1 and the outer tube 2.

[0040] refer to Figure 5 The first heat insulation layer 6 and the second heat insulation layer 7 are both made of heat insulation cotton. By setting the materials of the first heat insulation layer 6 and the second heat insulation layer 7, the fiber interwoven structure of the heat insulation cotton forms a large number of nanoscale pores, which can effectively block the heat conduction of solids.

[0041] refer to Figure 1 Both the inner tube 1 and the outer tube 2 are made of stainless steel. By setting the materials of the inner tube 1 and the outer tube 2, the high strength of stainless steel can withstand the radial pressure of high-pressure steam, preventing the tube body from deforming. In addition, the toughness of stainless steel can absorb the stress generated by the thermal expansion and contraction of the pipeline or external vibration, thus extending its service life.

[0042] refer to Figure 4 The width of microchannel 3 is 4-6mm. By setting the width of microchannel 3, a width of 4-6mm can accommodate a sufficient amount of phase change material to meet the transient heat load requirements of high-temperature steam transportation. The matching of the width of microchannel 3 with the latent heat of melting of phase change material ensures that the phase change material can completely melt / solidify when the steam temperature fluctuates, avoiding the heat capacity decay caused by partial phase change.

[0043] refer to Figure 1 The infrared radiation reflective layer 5 can be made of aluminum with a polished surface. By setting the material of the reflective layer, aluminum can achieve a reflectivity of 90%-95% in the infrared band, which can better reflect the thermal radiation of high-temperature steam.

[0044] Brief description of usage:

[0045] In use, the insulation pipe is first composed of an inner pipe 1 and an outer pipe 2, with a microchannel 3 formed between the inner pipe 1 and the outer pipe 2. At the same time, the support frame 4 is distributed in a hexagonal cross-section to maintain the stability of the pipe structure. Then, the infrared radiation reflective layer 5 can block heat radiation. Then, the first insulation layer 6 is spliced ​​together by two semi-circular components to form an initial thermal resistance barrier, blocking most of the direct conduction path. The second insulation layer 7 adopts the same structure but is staggered from the first layer seam, covering the splicing gap of the first layer, forcing heat to penetrate more layers of material. By extending the heat flow path and increasing the interface thermal resistance, dual heat insulation is achieved. Then, the outer protective layer 8 resists mechanical impact, chemical corrosion and environmental aging.

[0046] Then, the spiral groove 9 guides the high-temperature steam to form a spiral flow, forces the fluid to generate centrifugal motion, destroys the laminar boundary layer, enhances the convective heat transfer efficiency of the inner tube 1, and can increase the contact area between the steam and the inner wall, increase the surface area base of heat exchange, and the high thermal conductivity graphite sheet 10 is evenly distributed along the spiral groove 9, which quickly conducts the local high temperature of the inner wall along the axial direction, eliminates "hot spots" and homogenizes the temperature field.

[0047] Finally, when high-temperature steam passes through, the phase change material absorbs heat and melts, storing latent heat and accelerating thermal equilibrium. When the steam temperature fluctuates, the phase change material suppresses sudden temperature changes in the pipe wall through phase change, reducing thermal stress. The 4-6mm microchannel 3 width can accommodate a sufficient amount of phase change material to meet the transient heat load requirements of high-temperature steam transportation. The matching of the microchannel 3 width with the latent heat of melting of the phase change material ensures that the phase change material can completely melt / solidify when the steam temperature fluctuates, avoiding heat capacity decay caused by partial phase change.

[0048] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

Claims

1. A multi-layer insulated pipe for conveying high-temperature steam, comprising an inner pipe (1) and an outer pipe (2), characterized in that: A microchannel (3) is formed between the inner tube (1) and the outer tube (2). A support frame (4) is fixedly installed on the outer tube (2). There are several support frames (4) arranged in a circle. The cross-section of the support frame (4) is hexagonal. An infrared radiation reflective layer (5) is provided on the outside of the support frame (4). A first heat insulation layer (6) is provided on the infrared radiation reflective layer (5). The first heat insulation layer (6) is composed of two semicircles. A second heat insulation layer (7) is provided on the first heat insulation layer (6). The second heat insulation layer (7) is composed of two semicircles. The second heat insulation layer (7) and the first heat insulation layer (6) are staggered. A protective layer (8) is provided on the outside of the second heat insulation layer (7).

2. The multi-layer insulated pipe for conveying high-temperature steam according to claim 1, characterized in that: The inner wall of the inner tube (1) is provided with a spiral groove (9), and a high thermal conductivity graphite sheet (10) is provided inside the spiral groove (9). The number of high thermal conductivity graphite sheets (10) is several and they are evenly arranged.

3. The multi-layer insulated pipe for conveying high-temperature steam according to claim 1, characterized in that: The microchannel (3) is filled with a phase change material, which may be composed of NaNO3-KNO3-LiNO3 eutectic salt.

4. The multi-layer insulated pipe for conveying high-temperature steam according to claim 1, characterized in that: The support frame (4) is filled with low thermal conductivity aerogel particles, which may be SiO2 aerogel.

5. A multi-layer insulated pipe for conveying high-temperature steam according to claim 1, characterized in that: The first heat insulation layer (6) and the second heat insulation layer (7) are both made of heat insulation cotton.

6. A multi-layer insulated pipe for conveying high-temperature steam according to claim 1, characterized in that: Both the inner tube (1) and the outer tube (2) are made of stainless steel.

7. A multi-layer insulated pipe for conveying high-temperature steam according to claim 1, characterized in that: The width of the microchannel (3) is 4-6 mm.

8. A multi-layer insulated pipe for conveying high-temperature steam according to claim 1, characterized in that: The infrared radiation reflective layer (5) may be made of aluminum and have a polished surface.

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