Composite insulation pipe

Abstract

The present invention discloses a composite thermal insulation pipe, comprising a pipe body, an inner liner, a support ring, an inner insulation layer and an outer insulation layer. The inner liner is sleeved inside the pipe body, and a plurality of pressure-equalizing holes are arranged on the inner liner; a plurality of support rings are sleeved on the outer wall of the inner liner at intervals, and the outer edges of the support rings are in contact with the inner wall of the pipe body; the inner insulation layer is arranged between two adjacent support rings to fill the space between the inner liner and the pipe body; the outer insulation layer is sleeved on the outer side of the pipe body. The technical solution disclosed in the present invention can achieve less heat energy loss, shorter time to reach thermal equilibrium, and faster thermal response speed when the pipe is started at room temperature by arranging an inner insulation layer with small specific heat in the pipe body. The technical solution disclosed in the present invention is particularly suitable for long-distance transportation pipelines, which reduces investment cost and operation cost and prolongs service life.

Description

Technical Field

[0001] The present disclosure relates to the technical field of thermal insulation pipes, and in particular to a composite thermal insulation pipe. Background Art

[0002] Pipelines are widely used to transport fluids in industries such as oil and gas, chemical companies, and power plants. Pipeline insulation can effectively ensure the temperature of the transported fluid and reduce the operating costs of the pipeline. In addition, in the field of aircraft engine and gas turbine component test benches, taking the combustion chamber test bench as an example, according to the changing characteristics of the combustion chamber inlet air, its pressure and temperature change greatly. The current temperature is as high as 800°C, and the pressure ranges from normal pressure to 5MPa. The pipeline that undertakes the air transportation function needs to respond quickly. On the one hand, it is expected to shorten the cycle from starting the engine to reaching thermal equilibrium. On the other hand, from the perspective of changing operating conditions, it is expected to respond quickly according to the requirements of changing operating conditions.

[0003] For pressure pipes used in high temperature environments (above 600°C), the tensile strength of general metal materials decreases rapidly as the temperature rises. Therefore, high temperature and high pressure (3-10MPa) pipes are generally made of expensive high temperature alloy materials. However, there are still many problems to be solved and optimized:

[0004] (1) When a conventional externally insulated pipeline is started at room temperature, due to the large volume specific heat of the metal pipeline material, it takes a long time for the pipeline to reach thermal equilibrium at room temperature, and the dynamic thermal response speed of the pipeline when the working condition changes is slow. Moreover, under the same working condition, the longer the pipeline transportation distance, the longer the thermal equilibrium time of the pipeline, and the slower the dynamic thermal response speed;

[0005] (2) For pipelines with high working temperatures, in order to avoid a series of thermal stress hazards caused by excessive pipeline heating rate, the equipment pipelines are often preheated for a period of time before starting. The preheating process takes a long time before the equipment pipelines start, and the dynamic thermal response speed is slow, while also adding a certain amount of preheating operation costs;

[0006] (3) The metal pipe body of the conventional external insulation pipe is in direct contact with the fluid in the pipe, and forced convection heat exchange is carried out. The thermal conductivity of the metal material is relatively large, which causes the metal pipe of the conventional external insulation pipe to absorb heat and heat up rapidly. The direct impact is that the air flow temperature at the pipe outlet is low before reaching thermal equilibrium. At the same time, the temperature gradient of the metal pipe body along the axial direction is also large, and the thermal stress is large, which causes great damage to the metal pipe body and affects the service life.

[0007] (4) For long-distance high-temperature and high-pressure pipelines, high-temperature alloys are used as pipeline materials, which makes the investment cost of the entire pipeline high; at the same time, the working temperature of the pipeline in a steady state is basically the same as the temperature of the fluid in the pipe, and the thermal expansion compensation required for the pipeline is large, which is costly;

[0008] (5) When the pipeline is in stable operation, the working temperature of the pipeline material is basically the same as the temperature of the fluid in the pipe. The frequent start and stop of the equipment causes its temperature to rise from room temperature to working temperature, and then drop from working temperature to room temperature, or the pipeline's operating conditions change. Frequent and large-scale heating and cooling can easily cause thermal fatigue and even cracks in the pipeline, affecting the service life of the pipeline. Summary of the invention

[0009] In the prior art, conventional external insulated pipes start at room temperature, and it takes a long time to reach thermal equilibrium, the dynamic thermal response speed is slow, and the investment cost is high. In addition, the preheating process increases the operating cost. At the same time, frequent and large-scale heating and cooling can easily cause thermal fatigue and even cracks in the pipe, affecting the service life of the pipe. In view of the above defects, the present invention provides a heat-insulated pipe structure for use under high temperature and high pressure, which adopts an internal and external composite insulation structure. The heat balance time required for the pipe to start at room temperature is short, the thermal response speed of the variable working condition is fast, and the insulation effect is good. At the same time, the temperature resistance requirements for the main material of the metal pipe are reduced, and the service life of the pipe is increased.

[0010] In order to achieve the above objectives, the present disclosure provides the following technical solutions.

[0011] A composite thermal insulation pipe comprises a pipe body, an inner lining pipe, a support ring, an inner thermal insulation layer and an outer thermal insulation layer.

[0012] The inner liner pipe is sleeved inside the pipeline body, and a plurality of pressure equalizing holes are arranged on the inner liner pipe.

[0013] The support rings, a plurality of the support rings are sleeved on the outer wall of the inner liner pipe at intervals, and the outer edges of the support rings are in contact with the inner wall of the pipe body.

[0014] The inner insulation layer is arranged between two adjacent support rings and is used to fill the space between the inner liner pipe and the pipeline body.

[0015] The outer insulation layer is sleeved on the outside of the pipeline body.

[0016] According to some embodiments provided by the present disclosure, the inner liner pipe includes a perforated pipe and a filter screen, and the filter screen is sleeved on the outer wall of the perforated pipe to prevent debris of the inner insulation layer from falling into the inner liner pipe.

[0017] According to some embodiments provided in the present disclosure, the perforated tube is a metal perforated tube, the filter screen is a metal filter screen, and the perforated tube and the filter screen are sintered and connected together.

[0018] According to some embodiments provided by the present disclosure, the total area of ​​the equalizing pressure holes is less than 10% of the surface area of ​​the liner pipe, and the pore diameter of the equalizing pressure holes is less than 2 mm.

[0019] According to some embodiments provided by the present disclosure, the holes on the liner pipe are completely through holes or bridge holes.

[0020] According to some embodiments provided in the present disclosure, a plurality of air holes are provided on the support ring.

[0021] According to some embodiments provided by the present disclosure, the outer diameter of the support ring is 1 mm to 2 mm smaller than the inner diameter of the pipe body, and is used for thermal expansion compensation.

[0022] According to some embodiments provided by the present disclosure, the outer thermal insulation layer includes multiple layers of thermal insulation cotton and multiple layers of metal foil, and the multiple layers of thermal insulation cotton and the multiple layers of metal foil are spaced apart and sleeved.

[0023] According to some embodiments provided by the present disclosure, a protective layer is provided on the outside of the outer thermal insulation layer.

[0024] According to some embodiments provided by the present disclosure, the inner insulation layer includes high-temperature resistant silicate ceramic fibers, and the inner insulation layer is bundled on the inner liner pipe by steel wires, and the bundling spacing is 100 mm to 150 mm.

[0025] It can be seen from the above technical solutions that the composite thermal insulation pipe disclosed in the present invention has at least one or part of the following beneficial effects.

[0026] ① By setting an inner insulation layer with a small specific heat inside the pipeline body, it is possible to achieve less heat energy loss when the pipeline is started at room temperature, a shorter time is required to reach thermal equilibrium, and a faster thermal response speed, which is particularly suitable for long-distance transportation pipelines. Taking a DN800 pipeline as an example, when the pipe length is 550 meters, the thermal response time of the inner insulation pipeline is only 12 minutes, which is about 1 / 10 of that of the ordinary outer insulation pipeline in the prior art;

[0027] ② Because of its fast thermal response speed, preheating is not required, which reduces the number of processes, improves efficiency, and reduces investment and operating costs;

[0028] ③ Due to the heat insulation effect of the inner insulation layer, the temperature of the pipeline body rises mainly through heat conduction, which is transferred from the inner insulation layer to the metal pipeline body, rather than direct forced convection heat exchange with the gas in the pipe. Therefore, even if the internal and external composite insulation pipeline is directly started at room temperature, there will be no thermal stress hazards caused by excessive heating rate of the pipeline body, which prolongs the service life;

[0029] ④ In view of the high temperature of the high-temperature compressed air pipeline in the prior art, which requires the selection of expensive high-temperature alloy pipelines, the internal and external composite insulation pipeline provided by the present invention places the insulation layer on the inner side of the pipeline body, thereby reducing the working temperature of the pipeline body, that is, reducing the temperature requirements of the pipeline body material, thereby reducing the investment cost;

[0030] ⑤ Due to the heat insulation effect of the inner insulation layer, the working temperature of the pipeline body will be much lower than the gas temperature in the pipe even in a steady state. At the same time, for equipment pipelines that are frequently started and stopped or have variable working conditions, the temperature fluctuation amplitude of the metal pipeline body can be reduced, thereby effectively reducing thermal fatigue damage and extending service life;

[0031] ⑥ The inner liner made of sintered perforated tube and filter screen is placed inside the inner insulation layer, which can not only ensure that there is no pressure difference on both sides of the inner liner, but also prevent the fibers or debris of the inner insulation layer material from mixing into the pipeline airflow;

[0032] ⑦ The external insulation layer laid on the outside of the pipeline body can ensure that the temperature of the metal pipeline body will not be lower than the pressure dew point temperature of the fluid in the pipe, thereby preventing condensation of gas in the pipe from reducing the thermal insulation performance of the internal insulation layer and avoiding dew point corrosion of the metal pipeline body. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The overall main cross-sectional perspective structure diagram of the embodiment of the present disclosure is schematically shown;

[0034] Figure 2 Schematically shows a main structural diagram of an embodiment of the present disclosure;

[0035] Figure 3 A three-dimensional diagram of a liner pipe according to an embodiment of the present disclosure is schematically shown;

[0036] Figure 4 A perspective view of a support ring according to an embodiment of the present disclosure is schematically shown.

[0037] Figure 5 Schematically shows a schematic diagram of the overall main cross-sectional three-dimensional structure of another embodiment of the present disclosure;

[0038] Figure 6 Schematically shows a main structural diagram of another embodiment of the present disclosure;

[0039] Figure 7 A perspective view of a liner pipe according to another embodiment of the present disclosure is schematically shown;

[0040] Figure 8 Schematically shown as Figure 7 The enlarged structural diagram at A in the middle;

[0041] Among them, 1 represents the inner lining pipe; 2 represents the support ring; 3 represents the inner insulation layer; 4 represents the pipeline body; 5 represents the outer insulation layer; 6 represents the perforated pipe; 7 represents the filter screen; 8 represents the pressure-equalizing hole; 9 represents the air vent; 10 represents the metal foil; 11 represents the outer protective layer; 12 represents the insulation cotton; 13 represents the steel wire; and 14 represents the bridge hole. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0043] But it should be understood that these descriptions are exemplary only, and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, the description of known techniques is omitted to avoid unnecessary confusion of concepts of the present invention.

[0044] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0045] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used here should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner. For example, the normal pressure mentioned in this disclosure is a standard atmospheric pressure, about 0.1 MPa, which varies slightly depending on the experimental location; for example, the high temperature mentioned in this disclosure is defined as a range above 600°C, that is, high temperature; the high pressure mentioned in this disclosure is defined as a range of 3-10 MPa; the steady state mentioned in this disclosure is the steady state of the fluid, that is, the fluid parameters in the pipeline do not change with time, such as flow rate, temperature, pressure density, etc.; In addition, the sintering mentioned in this disclosure originally refers to the conversion of powdered materials into dense bodies, which is a traditional process. People have long used this process to produce ceramics, powder metallurgy, refractory materials, ultra-high temperature materials, etc. Here, it refers to the process of tying and fixing the metal perforated tube and the metal filter screen and then putting them into the kiln for heating to combine the two.

[0046] In addition, the composite thermal insulation pipe provided by the present disclosure is provided with an inner liner pipe with holes, so it is particularly suitable for the transportation of high-temperature and high-pressure gases.

[0047] The present invention provides a composite thermal insulation pipe. Figure 1 The overall main cross-sectional perspective structure diagram of the embodiment of the present disclosure is schematically shown; Figure 2 The main structural diagram of an embodiment of the present disclosure is schematically shown.

[0048] like Figure 1 As shown, it includes an inner liner pipe 1, a support ring 2, an inner insulation layer 3, a pipeline body 4, and an outer insulation layer 5.

[0049] According to some embodiments provided by the present disclosure, Figure 1 , Figure 2 As shown, the inner liner pipe 1 is sleeved inside the pipeline body 4, and a plurality of equalizing pressure holes 8 are provided on the inner liner pipe 1.

[0050] According to some embodiments provided by the present disclosure, a support ring 2 or a plurality of support rings 2 are sleeved on the outer wall of the liner pipe 1 at intervals, and the outer edge of the support ring 2 contacts the inner wall of the pipe body 4 .

[0051] According to some embodiments provided by the present disclosure, the inner insulation layer 3 is disposed between two adjacent support rings 2 to fill the space between the inner liner pipe 1 and the pipeline body 4 .

[0052] According to some embodiments provided by the present disclosure, the outer insulation layer 5 is sleeved on the outside of the pipeline body 4.

[0053] Among them, the inner space of the pipeline body 4 is divided into two parts by the inner liner 1, and the inner insulation layer 3 is filled in the space between the inner liner 1 and the pipeline body 4. The inner insulation layer 3 is made of a material with a small specific heat, which can change the defects of ordinary pipelines in the prior art. The high-temperature gas in the ordinary pipeline performs forced convection heat exchange on the metal pipeline body. Because the thermal conductivity of the metal pipeline body is large, it will cause rapid heat absorption and temperature rise, which directly leads to a low temperature of the air flow at the pipeline outlet before thermal equilibrium, wasting a lot of heat; at the same time, the temperature gradient of the metal pipeline body along the axial direction is also large, and the thermal stress is large, which seriously affects the service life of the pipeline. The composite insulated pipeline provided by the present disclosure is provided with an additional inner liner 1, and at the same time, an inner insulation layer with a small specific heat is filled between the inner liner 1 and the pipeline body 4, so as to change the heat absorption mode of the pipeline body 4 from direct forced convection heat exchange to indirect heat absorption through heat conduction of the inner insulation layer 3, slowing down the heat absorption speed of the pipeline body 4 and reducing the speed of heat loss. That is, the air flow temperature at the pipeline outlet can quickly reach the preset temperature and reach the time period required for thermal equilibrium, and the thermal response speed is fast. Taking a DN800 pipe as an example, when the pipe is 550 meters long, the traditional ordinary pipe takes about 120 minutes from startup to thermal equilibrium. The thermal response speed is too slow and generally requires preheating. However, the composite insulated pipe provided in this application, under the same conditions, takes only 12 minutes to reach a steady state, and the thermal response time is only 1 / 10 of that of existing ordinary pipes, greatly shortening the thermal response time. At the same time, the preheating time can be reduced or no preheating is required, greatly reducing investment costs and operating costs.

[0054] In addition, in the prior art, when the pipeline reaches a steady state, the temperature of the pipeline body of the ordinary pipeline is the same as the temperature of the fluid in the pipeline body. However, the composite thermal insulation pipeline provided by the present disclosure can reduce the temperature of the pipeline body 4 after reaching a steady state by adding an inner thermal insulation layer 3 inside the pipeline body 4, thereby reducing the material requirements of the pipeline body 4 and reducing the investment cost of the pipeline.

[0055] In addition, by adding an inner insulation layer 3 inside the pipe body 4, the temperature difference of the high-temperature airflow in various axial areas inside the pipe body is small. With the action of the inner insulation layer 3, the temperature difference of various areas of the pipe body 4 along the axial direction is very small, that is, the temperature gradient of the pipe body 4 along the axial direction is small, the temperature stress is small, the damage to the pipe body 4 is small, and the service life of the composite insulation pipe is extended.

[0056] Finally, for equipment pipelines that are frequently started and stopped or have changing operating conditions, the pipeline body of the composite insulated pipeline provided by the present invention can reduce the impact on the pipeline body 4 and reduce the temperature fluctuation amplitude of the pipeline body 4 by adding an inner insulation layer 3 inside the pipeline body 4, thereby effectively reducing thermal fatigue damage and extending the service life.

[0057] According to some embodiments provided by the present disclosure, Figure 3 A three-dimensional view of a liner pipe according to an embodiment of the present disclosure is schematically shown.

[0058] like Figure 3 As shown, a plurality of pressure-equalizing holes 8 are provided on the inner liner 1. By providing a plurality of pressure-equalizing holes 8 on the inner liner 1, the gas pressure on both sides of the inner liner 1 can be balanced to prevent the high-pressure gas from damaging the inner liner. The inner liner 1 is only used to fix and position the inner insulation layer 3, and is not used as a force-bearing component.

[0059] According to some embodiments provided by the present disclosure, the inner liner pipe 1 includes a perforated pipe 6 and a filter screen 7. The filter screen 7 is sleeved on the outer wall of the perforated pipe 6 to prevent debris of the inner insulation layer from falling into the inner liner pipe.

[0060] According to some embodiments provided by the present disclosure, the perforated tube 6 is a metal perforated tube, the filter screen 7 is a metal filter screen, and the perforated tube 6 and the filter screen 7 are sintered and connected together.

[0061] Among them, a plurality of equalizing pressure holes 8 are evenly distributed on the perforated tube 6. During the manufacturing process, the filter screen 7 is wrapped on the outer surface of the perforated tube 6, and the two are fixed together by bundling, welding or other methods.

[0062] An optional solution is to put the orifice tube 6 and filter screen 7 that are temporarily fixed together into a furnace, heat and sinter them into a whole. The advantage is that the combination of the orifice tube 6 and the filter screen 7 is more stable, and because they are sintered into a whole under high temperature environment after heating, there will be no situation where the two are firmly bonded before use, but during use, the bond between the two is broken due to the increase in heating temperature, causing damage to the composite insulation pipe.

[0063] A further optional solution is to use a multi-layer filter screen 7 wrapped on the outer surface of the perforated tube 6. This prevents the single-layer filter screen 7 from being damaged during sintering, transportation or installation, resulting in the mesh of the filter screen 7 being too large, and then during use, the broken fiber debris of the inner insulation layer 3 falls into the inner liner tube 1 and mixes with the airflow.

[0064] Specifically, the inner lining pipe 1 may be made of high temperature resistant stainless steel such as 316L stainless steel or 310S according to the temperature range of the gas fluid inside the composite thermal insulation pipe.

[0065] According to some embodiments provided by the present disclosure, the total area of ​​the equalizing pressure holes 8 is less than 10% of the surface area of ​​the liner pipe 1 , and the pore diameter of the equalizing pressure holes 8 is less than 2 mm.

[0066] Among them, when making the inner lining tube 1, the smaller the aperture of the pressure equalizing hole 8, the better, and the larger the area occupied by the pressure equalizing hole 8, the better the pressure equalizing effect. However, as the aperture decreases, the processing difficulty also increases, that is, the cost increases. As the area occupied by the pressure equalizing hole 8 increases, the strength of the inner lining tube 1 decreases. After comprehensive consideration, an optimal scheme is that the total area of ​​the pressure equalizing holes 8 is less than 10% of the surface area of ​​the inner lining tube 1, and the aperture of the pressure equalizing hole 8 is less than 2mm, which can ensure the strength of the inner lining tube 1 and the good air permeability of the inner lining tube 1. The air pressure on both sides of the inner lining tube 1 can quickly reach balance to prevent the inner lining tube 1 from being damaged by force and affecting its use.

[0067] According to some embodiments provided by the present disclosure, Figure 5 Schematically shows a schematic diagram of the overall main cross-sectional three-dimensional structure of another embodiment of the present disclosure; Figure 6 Schematically shows a main structural diagram of another embodiment of the present disclosure; Figure 7 A perspective view of a liner pipe according to another embodiment of the present disclosure is schematically shown; Figure 8 Schematically shown as Figure 7 Enlarged structural diagram at A in the middle.

[0068] like Figures 5 to 8 As shown, the hole on the liner pipe 1 is a bridge-type hole 14 .

[0069] Among them, the bridge hole 14 is commonly seen in the bridge filter pipe, which is generally a rectangular hole. Compared with the traditional through hole, the four sides of the bridge hole 14, the two opposite sides are disconnected, and the other two opposite sides are adhered to the surrounding structure of the hole and bulge in one direction to form a structure similar to a "bridge". It is engaged in hydrogeological exploration, drilling, well construction, reservoir precipitation, foundation deep excavation precipitation, geothermal development and utilization, mineral water development and utilization, geothermal air conditioning, bad well repair, underground water source water extraction, etc. The special hole structure of the water filter has the effect of enhancing the mechanical strength of the water filter and has high mechanical strength. However, in the present disclosure, the bridge hole 14 is mainly used. After bulging upward, the high-temperature and high-pressure airflow will change its direction after passing through the bridge hole 14, from the axial direction perpendicular to the pipe body 4 to the axial direction parallel to the pipe body 4. The benefit is that it can reduce the damage of the high-temperature and high-pressure gas passing through the equalizing pressure hole 8 to the inner insulation layer 3, and prevent the airflow from causing a through hole perpendicular to the axial direction of the pipe body 4 to the inner insulation layer 3, thereby forming a structure with a "thermal bridge" function, so that the high-temperature gas inside the composite insulation pipe can be in contact with the pipe body 4 locally, thereby forming forced convection heat exchange, causing the pipe body 4 to absorb heat too quickly, and the temperature rises too quickly, thereby affecting the thermal response speed. In addition, the structural strength of the inner liner 1 with a bridge hole 14 of the same thickness is higher than that of the inner liner 1 with a through hole, that is, under the premise of ensuring that the inner liner 1 is within the specified strength range, the equalizing pressure hole 8 adopts a bridge hole 14 structure, which can reduce the thickness of the inner liner 1 or increase the area ratio of the equalizing pressure hole 8, which can reduce costs or improve efficiency.

[0070] According to some embodiments provided by the present disclosure, the outer diameter of the support ring 2 is 1 mm to 2 mm smaller than the inner diameter of the pipe body 4, and is used for thermal expansion compensation.

[0071] Among them, the function of the support ring 2 is to connect, fix and position the inner liner pipe 1 in the pipeline body 4. In actual operation, the outer diameter of the support ring 2 is slightly smaller than the inner diameter of the pipeline body 4, and the difference is about 1mm to 2mm, which is convenient for the assembly of the composite insulation pipeline and used as thermal expansion compensation during working state.

[0072] According to some embodiments provided by the present disclosure, Figure 4 A perspective view of a support ring according to an embodiment of the present disclosure is schematically shown.

[0073] like Figure 4 As shown, a plurality of air holes 9 are provided on the support ring 2 .

[0074] The provision of multiple air holes allows the space between the inner liner pipe 1 and the pipe body 4 of the composite thermal insulation pipe to be relatively connected in the axial direction, that is, the tiny airflow in the inner thermal insulation layer 3 can flow through the multiple air holes 9, reducing the possibility of excessive local air pressure or temperature in the inner thermal insulation layer 3, and extending the service life. At the same time, the provision of multiple air holes 9 on the support ring 2 can appropriately reduce the weight of the support ring, facilitate installation, and reduce costs.

[0075] According to some embodiments provided in the present disclosure, the inner insulation layer 3 includes high-temperature resistant silicate ceramic fibers, and the inner insulation layer 3 is bundled on the inner liner pipe 1 by steel wires, and the bundling spacing is 100 mm to 150 mm.

[0076] During the installation process, multiple support rings 2 are fixed to the inner liner 1 at equal distances by welding, wherein the welding points should be avoided at the pressure-balancing holes 8 or rectangular pressure-balancing holes 14 of the orifice tube 6. This prevents the inner liner 1 from squeezing one side of the inner thermal insulation layer 3 due to its own weight or airflow impact, causing gaps on the other side, thereby affecting the thermal insulation effect of the inner thermal insulation layer 3.

[0077] In some optional solutions, the inner insulation layer material can be made of silicate ceramic fiber products mixed with a certain amount of water repellent to prevent the thermal insulation performance of the inner insulation layer 3 from being affected by moisture.

[0078] In some optional schemes, the inner insulation layer 3 is covered on the outside of the inner lining pipe 1 and is placed between each support ring 2, and the inner insulation layer 3 is tied with a steel wire 13, and the tying spacing is controlled between 150mm and 200mm. The outer diameter of the inner insulation layer 3 after tying should be equal to or basically equal to the outer diameter of the support ring 2 (the error range is controlled within ±1mm) to facilitate the assembly and installation of the composite insulation pipe.

[0079] According to some embodiments provided by the present disclosure, the outer insulation layer 5 includes multiple layers of insulation cotton 12 and multiple layers of metal foil 10, and the multiple layers of insulation cotton 12 and the multiple layers of metal foil 10 are alternately arranged.

[0080] Among them, the multi-layer heat-insulating cotton 12 and the multi-layer metal foil 10 are alternately sleeved on the outside of the pipe body 4, that is, a layer of heat-insulating cotton 12 is laid on the outside of the pipe body 4, and then a layer of metal foil 10 is laid, and the multi-layer heat-insulating cotton 12 and metal foil 10 are repeatedly laid. The heat-insulating cotton 12 is selected from heat-insulating materials with high temperature resistance and small specific heat, and its purpose is to reduce the heat transfer from the pipe body 4 to the surrounding environment. In combination with the multi-layer metal foil 10, it can reflect part of the heat radiation of the pipe body 4, further reducing the heat energy emitted by the pipe body 4 to the external environment, causing energy loss.

[0081] As an optional solution, the metal foil 10 can be aluminum foil.

[0082] According to some embodiments provided by the present disclosure, a protective layer 11 is provided on the outside of the outer thermal insulation layer 5 .

[0083] Specifically, iron sheets can be selected as the material of the protective layer 11 , and the iron sheets can be cut and overlapped according to the size of the composite thermal insulation pipe after the outer thermal insulation layer 5 is installed to protect and fix the outer thermal insulation layer.

[0084] So far, the embodiments of the present disclosure have been described in detail in conjunction with the accompanying drawings. It should be noted that the implementation methods not shown or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each component are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them.

[0085] It should also be noted that, in the specific embodiments of the present disclosure, unless otherwise indicated, the numerical parameters in the present specification and the attached claims are approximate values ​​and can be changed according to the desired characteristics obtained through the content of the present disclosure. Specifically, all numbers used in the specification and claims to express the size, range conditions, etc. of the composition should be understood to be modified by the term "about" in all cases. In general, the meaning of the expression refers to the change of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments by a specific number.

[0086] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All of these combinations and / or combinations fall within the scope of the present invention.

[0087] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite thermal insulation pipe, characterized in that: include: Pipeline body; An inner liner pipe is sleeved inside the pipeline body, and a plurality of pressure equalization holes are arranged on the inner liner pipe; Support rings, a plurality of said support rings are sleeved on the outer wall of said inner liner pipe at intervals, and the outer edges of said support rings are in contact with the inner wall of said pipe body; An inner insulation layer, disposed between two adjacent support rings, and used to fill the space between the inner liner pipe and the pipeline body; An outer insulation layer is sleeved on the outside of the pipeline body; The support ring is provided with a plurality of air holes.

2. The composite thermal insulation pipe according to claim 1, characterized in that: The inner liner pipe comprises a perforated pipe and a filter screen, wherein the filter screen is sleeved on the outer wall of the perforated pipe to prevent the debris of the inner insulation layer from falling into the inner liner pipe.

3. The composite thermal insulation pipe according to claim 2, characterized in that: The perforated tube is a metal perforated tube, the filter screen is a metal filter screen, and the perforated tube and the filter screen are sintered and connected together.

4. The composite thermal insulation pipe according to claim 1, characterized in that: The total area of ​​the equalizing pressure holes is less than 10% of the surface area of ​​the inner liner pipe, and the aperture of the equalizing pressure holes is less than 2 mm.

5. The composite thermal insulation pipe according to any one of claims 1 to 4, characterized in that: The pressure-equalizing hole on the inner liner pipe is a completely through hole or a bridge hole.

6. The composite thermal insulation pipe according to claim 1, characterized in that: The outer diameter of the support ring is 1 mm to 2 mm smaller than the inner diameter of the pipe body and is used for thermal expansion compensation.

7. The composite thermal insulation pipe according to claim 1, characterized in that: The outer heat-insulating layer comprises multiple layers of heat-insulating cotton and multiple layers of metal foil, and the multiple layers of heat-insulating cotton and the multiple layers of metal foil are sleeved at intervals.

8. The composite thermal insulation pipe according to claim 7, characterized in that: A protective layer is arranged outside the outer thermal insulation layer.

9. The composite thermal insulation pipe according to claim 1, characterized in that: The inner thermal insulation layer comprises high temperature resistant silicate ceramic fibers, and the inner thermal insulation layer is bundled on the inner liner pipe by steel wires, with a bundling spacing of 100 mm to 150 mm.

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