Bridge-cutting heat-insulating composite prefabricated overhead thermal-insulation pipe and manufacturing method thereof

Abstract

The present application relates to the technical field of heat pipe, especially to a kind of broken bridge heat insulation composite prefabricated overhead thermal insulation pipe and its manufacturing method, wherein the prefabricated overhead thermal insulation pipe includes working steel pipe, and a plurality of hard insulation layers are arranged on the working steel pipe in axial direction, a plurality of soft insulation layers are arranged between two adjacent hard insulation layers, and a reflecting layer is arranged on the surface of each soft insulation layer, an inner fixed pipe is arranged on the surface of each hard insulation layer and the outermost reflecting layer, a foaming layer is arranged on the surface of the inner fixed pipe, and an outer protective pipe is arranged on the surface of the foaming layer.The prefabricated overhead thermal insulation pipe adopts the structure of hard insulation layer combined with soft insulation layer, and has both structural stability and thermal insulation performance, cancels air layer, avoids thermal bridge effect, effectively prevents heat loss in the pipe, the overall structure does not need maintenance, significantly improves the strength of the thermal insulation layer and the thermal insulation effect of long-period use of the thermal insulation structure.

Description

Technical Field

[0001] This invention relates to the field of thermal pipeline technology, and in particular to a thermally broken composite prefabricated overhead insulated pipe and its manufacturing method. Background Technology

[0002] In industrial production, residential heating, and other fields, a large amount of heat energy needs to be extracted and used from heating systems. Thermal power plants, as the "heart" of the heating system, continuously provide heat energy, while heat pipelines act as the "blood vessels," serving as crucial infrastructure for transporting heat energy carriers such as hot water and steam.

[0003] Among them, the two most important parameters of thermal pipelines are thermal insulation performance and structural strength, which directly affect energy consumption and service life. Common pipe insulation structures are divided into rigid and flexible materials. Rigid materials make the pipe structure reliable, but the thermal insulation performance is poor; flexible materials have better thermal insulation performance, but may collapse, settle, or hollow out under conditions such as hoisting, transportation, installation, and trial operation. Therefore, reliable support structures need to be designed, which is also the current mainstream research and development direction.

[0004] The existing structure of flexible prefabricated steam insulation pipes involves wrapping a working steel pipe with flexible insulation and reflective materials, inserting an inner sleeve and an outer protective pipe, and then using a foaming machine to inject polyurethane foam into the cavities of the inner sleeve and outer protective pipe for foaming and curing. Because the flexible insulation material is relatively soft, the gap between the flexible insulation layer and the inner sleeve is relatively large after insertion. This not only affects the insulation effect of the pipeline, but also, after the pipeline is installed, deformation can easily occur at the pipe support and bracket locations due to the pipeline's own weight and vibrations generated during operation. This can lead to rupture of the polyurethane foam layer, increasing heat loss from the steam insulation pipeline.

[0005] In addition, due to insufficient clamping between the soft insulation layer and the working steel pipe, the thermal expansion and contraction of the working steel pipe leads to a large relative displacement between the soft insulation layer and the working steel pipe. In order to maintain the integrity of the polyurethane foam layer, soft prefabricated steam insulation pipes usually require a complex internal sliding pipe support system. However, the spacing of the supports of the internal sliding pipe support system on the soft prefabricated insulation pipe is determined during factory manufacturing. It is difficult to coordinate the spacing with the concrete support piers during on-site installation, which brings many inconveniences to the installation and construction of prefabricated insulation pipes. Summary of the Invention

[0006] In view of the above problems, one object of the present invention is to provide a thermally broken composite prefabricated overhead insulated pipe, which improves the overall pipe insulation effect and eliminates the problem of relative sliding between the soft insulation layer and the working steel pipe, thus facilitating the on-site installation and construction of the prefabricated insulated pipe.

[0007] Another objective of this invention is to provide a method for manufacturing a thermally broken composite prefabricated overhead insulated pipe, which facilitates mass production and on-site construction.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A prefabricated overhead insulated pipe with thermal break and insulation includes a working steel pipe with several rigid insulation layers spaced apart along the axial direction. Several soft insulation layers are stacked and wrapped between two adjacent rigid insulation layers. Each soft insulation layer has a reflective layer on its surface. Each rigid insulation layer and the outermost reflective layer have an inner fixed pipe on their surfaces. The inner fixed pipe has a foamed layer on its surface. The foamed layer has an outer protective pipe on its surface.

[0010] Optionally, the rigid insulation layer includes a support ring made of microporous calcium silicate material, with the inner ring surface of the support ring abutting against the outer wall of the working steel pipe and the outer ring surface of the support ring abutting against the inner wall of the inner fixed pipe.

[0011] Optionally, multiple support rings are stacked in the radial direction of the working steel pipe, and a reflective layer is also provided between two adjacent stacked support rings.

[0012] Optionally, the soft insulation layer can be made of insulation cotton, and the reflective layer can be made of aluminum foil fiber cloth.

[0013] Optionally, the entire surface of the working steel pipe is coated with nano-aerogel.

[0014] Optionally, the internal fixing tube is formed by spirally winding steel strip around the surface of the rigid insulation layer and the reflective layer, so that the rigid insulation layer is in close contact with the inner surface of the steel strip, and the thickness of the soft insulation layer is compressed by 5%.

[0015] Optionally, the outer protective tube is made of strip steel plate spirally rolled into a cylindrical shape.

[0016] Optionally, the surface of the outer protective tube is provided with several fixed tube supports at intervals along the axial direction, and the spacing between adjacent fixed tube supports is adjustable.

[0017] Therefore, the aforementioned thermally broken composite prefabricated overhead insulated pipe has the following advantages:

[0018] (1) The combination of rigid insulation layer and soft insulation layer takes into account both structural stability and insulation performance.

[0019] (2) Eliminate the air layer in the insulated pipe to cut off the flow of air and avoid the thermal bridging effect;

[0020] (3) The internal fixed tube and the external protective tube work together to make the soft insulation layer and the foam layer a whole insulation structure to prevent the soft insulation layer from deforming after long-term operation.

[0021] (4) The multi-layer insulation structure effectively prevents heat loss from the pipe and reduces energy consumption;

[0022] (5) The relative displacement of rigid insulation layer is small, while soft insulation material can absorb the insulation expansion joint generated by thermal expansion and contraction, so there is no need to set up insulation expansion joint separately.

[0023] (6) The overall thermal break insulation structure requires no maintenance, is safe and reliable in long-term operation, significantly improves the strength of the insulation layer and the insulation effect of the insulation structure for long-term use, and can fully meet the safe use within the design life.

[0024] On the other hand, the present invention adopts the following technical solution:

[0025] A method for manufacturing a thermally broken composite prefabricated overhead insulated pipe, based on the aforementioned thermally broken composite prefabricated overhead insulated pipe, includes the following steps:

[0026] Step 1: Grind and polish the inner and outer surfaces of the working steel pipe, and apply an anti-corrosion layer to the outer surface of the working steel pipe.

[0027] Step 2: A rigid insulation layer is axially spaced on the surface of the working steel pipe, and a soft insulation layer is alternately wrapped in both directions between adjacent rigid insulation layers, with a reflective layer wrapped around the surface of each soft insulation layer.

[0028] Step 3: Spiral wind steel strips are wound around the rigid insulation layer and the outermost reflective layer to form an inner fixed tube, and the rigid insulation layer and the soft insulation layer are pressed together to obtain a prefabricated insulation pipe.

[0029] Step 4: Insert the prefabricated insulation pipe into the outer protective pipe, maintain the gap between the inner fixed pipe and the outer protective pipe, and inject foaming material into the gap to form a foaming layer;

[0030] Step 5: Reserve spaced fixed pipe supports on the surface of the outer protective pipe to fix it to the concrete support pier at the installation site.

[0031] Optionally, both ends of the working steel pipe are left with bare pipe sections that are not covered with rigid insulation layer, soft insulation layer, reflective layer, inner fixed pipe, foam layer and outer protective pipe. After welding is completed on the construction site, the bare pipe sections at the joint are then covered.

[0032] Therefore, the manufacturing method of the thermally broken composite prefabricated overhead insulated pipe can produce unit insulated pipe sections with thermal break insulation and high insulation performance in batches, which is convenient for on-site installation and greatly shortens the installation and construction cycle. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the thermally broken composite prefabricated overhead insulation pipe provided in an embodiment of the present invention;

[0034] Figure 2 yes Figure 1 Cross-sectional view at point AA;

[0035] Figure 3 yes Figure 1 Enlarged view at point B in the middle;

[0036] Figure 4 This is a schematic diagram of the installation of the fixed pipe support on the thermally broken composite prefabricated overhead insulated pipe provided in an embodiment of the present invention.

[0037] In the picture:

[0038] 1. Working steel pipe; 2. Rigid insulation layer; 3. Soft insulation layer; 4. Reflective layer; 5. Inner fixed pipe; 6. Foaming layer; 7. Outer protective pipe; 8. Nano aerogel; 9. Fixed pipe support; 10. Smooth pipe section. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, a mechanical connection, an electrical connection, or an indirect connection via an intermediate medium. They can also refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In the description of this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. The technical solutions of this invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0042] Please see Figures 1 to 3As shown, this preferred embodiment provides a thermally broken composite prefabricated overhead insulated pipe, including a working steel pipe 1. Several rigid insulation layers 2 are spaced apart along the axial direction on the working steel pipe 1. Several layered and wrapped soft insulation layers 3 are arranged between two adjacent rigid insulation layers 2. A reflective layer 4 is provided on the surface of each soft insulation layer 3. An inner fixing tube 5 is provided on the surface of each rigid insulation layer 2 and the outermost reflective layer 4. A foaming layer 6 is provided on the surface of the inner fixing tube 5. An outer protective tube 7 is provided on the surface of the foaming layer 6.

[0043] It should be noted that the combination of rigid insulation layer 2 and flexible insulation layer 3 takes into account both structural stability and insulation performance. Because the sliding displacement caused by thermal expansion of the working steel pipe 1 during operation is relatively large, while the tightness between the flexible insulation layer 3 and the working steel pipe 1 is insufficient, the relative displacement between the flexible insulation layer 3 and the working steel pipe 1 is relatively large when the working steel pipe 1 expands and contracts with temperature. Meanwhile, the relative displacement of the rigid insulation layer 2, as a support component of the internal insulation material, is relatively small. Therefore, a thermal break insulation structure of both flexible insulation layer 3 and rigid insulation layer 2 is used on the working steel pipe 1. The flexible insulation layer 3 can absorb the insulation expansion joints generated during thermal expansion and contraction, while the rigid insulation layer 2 can ensure structural strength.

[0044] In addition, the structure of the inner fixed pipe 5, the foam layer 6, and the outer protective pipe 7 makes each insulation material a whole, preventing the soft insulation layer 3 from deforming after long-term operation, reducing heat loss in the pipeline, and the overall thermal break insulation structure requires no maintenance, ensuring safe and reliable long-term operation. It significantly improves the strength of the insulation layer and the insulation effect of the insulation structure for long-term use, and can fully meet the safe use within the design life.

[0045] The rigid insulation layer 2 is preferably a support ring made of microporous calcium silicate material. The inner ring surface of the support ring is in contact with the outer wall of the working steel pipe 1, and the outer ring surface of the support ring is in contact with the inner wall of the inner fixed pipe 5. This not only improves the structural strength of the insulation layer, but also reduces the amount of rigid insulation material used.

[0046] Specifically, when the required thickness of the insulation layer is large, multiple support rings, corresponding to the thickness of the soft insulation layer 3, are stacked radially upwards on the working steel pipe 1. A reflective layer 4 is also provided between two adjacent stacked support rings. The figure shows an example of a stack of one 85mm microporous calcium silicate tile and two 80mm microporous calcium silicate tiles. Furthermore, the end faces of two adjacent stacked support rings are not flush to improve the continuity between the rigid insulation layer 2 and the soft insulation layer 3, avoiding the formation of obvious seams that could lead to excessive heat loss at the seams.

[0047] Among them, the entire surface of the working steel pipe 1 is coated with nano aerogel 8 after treatment. The nano aerogel 8 serves as the basic insulation layer and has extremely strong insulation properties. The figure shows an example of two layers of 10mm heating network-specific nano aerogel 8 felt.

[0048] Among them, the soft insulation layer 3 is preferably made of insulation cotton, such as one or more of high-temperature glass wool felt or aluminum silicate needled blanket, and the insulation materials of each layer are alternately wrapped in the forward or reverse direction. The figure shows an example of six layers of 40mm environmentally friendly high-temperature resistant glass wool.

[0049] Among them, the reflective layer 4 is preferably made of aluminum foil fiber cloth, which has the characteristics of being resistant to ultra-high temperature, high temperature, medium temperature and normal temperature according to the distribution of inner and outer layers.

[0050] The internal fixing tube 5 is preferably made of steel strip spirally wound on the surface of rigid insulation layer 2 and reflective layer 4, and fixed by spiral interlocking or intermittent welding. The thickness of the steel strip is about 0.3mm to 0.5mm and the width is 50mm to 300mm, so that the rigid insulation layer 2 is in close contact with the inner surface of the steel strip, and the thickness of the soft insulation layer 3 is compressed by 5%, ensuring a tight structure, no air layer, blocking the flow of air, and no thermal bridge effect.

[0051] The foaming layer 6 is preferably made of polyurethane foam, forming an environmentally friendly rigid polyurethane foam of about 50mm as shown in the figure.

[0052] The outer protective tube 7 is preferably made of a spiral rolled strip steel plate into a cylindrical shape. The steel plate is about 0.5mm to 2.0mm thick and 137mm to 300mm wide. The inner fixed tube 5 and the outer protective tube 7 are used to make the soft insulation layer 3 and the foam layer 6 into an integral insulation structure to prevent the soft insulation layer 3 from deforming after long-term operation.

[0053] Furthermore, since the working steel pipe 1, all the insulation layers, and the outer protective pipe 7 form an integral external sliding structure, several fixed pipe supports 9 can be axially spaced on the surface of the outer protective pipe 7, as shown in the installation structure. Figure 4 As shown, the fixed pipe support 9 here adopts a low-friction coefficient external sliding clamp pipe support, which makes the spacing between adjacent fixed pipe supports 9 adjustable to match the concrete support piers at the installation site. Furthermore, the support base plate of the fixed pipe support 9 has sufficient length allowance along the axial direction of the precast insulated pipe, improving adaptability. Moreover, to avoid damage to the entire pipe surface caused by the fixed pipe support 9, the fixed pipe support 9 is preferably positioned corresponding to the internal rigid insulation layer 2.

[0054] In this regard, this embodiment also provides a method for manufacturing the above-mentioned thermally broken composite prefabricated overhead insulation pipe, which includes the following steps:

[0055] Step 1: Grind and polish the inner and outer surfaces of the working steel pipe 1, and apply an anti-corrosion layer to the outer surface of the working steel pipe 1.

[0056] Specifically, by grinding and polishing the inner and outer surfaces of the working steel pipe 1, the surface roughness is reduced to below 6.3 μm, which can reduce the emissivity of the working steel pipe 1 by 80 to 100 times. The anti-corrosion layer on the outer surface of the working steel pipe 1 is preferably composed of an inorganic zinc-rich primer or an organosilicon powder heat-resistant primer and an organosilicon powder heat-resistant topcoat.

[0057] Step 2: A rigid insulation layer 2 is axially spaced on the surface of the working steel pipe 1, and a soft insulation layer 3 is alternately wrapped in both directions between adjacent rigid insulation layers 2, and a reflective layer 4 is wrapped around the surface of each soft insulation layer 3.

[0058] Among them, the nano-aerogel 8 serves as the basic insulation layer, closely attached to the anti-corrosion layer. When the soft insulation layer 3 has a multi-layer structure, insulation cotton is alternately wrapped in the forward or reverse direction, and the reflective layer 4 is wrapped around it layer by layer.

[0059] Step 3: Spiral wind steel strips are wound around the rigid insulation layer 2 and the outermost reflective layer 4 to form an inner fixed tube 5. The rigid insulation layer 2 and the soft insulation layer 3 are then pressed together to obtain a prefabricated insulation pipe.

[0060] Specifically, a special winding device is used to spirally wind a steel strip around the reflective layer 4. The edges of the steel strip have pre-pressed spiral seams or lap welds. During winding, the special device applies a predetermined tension force to the steel strip, causing it to press the soft insulation layer 3 and the reflective layer 4 onto the working steel pipe 1. Each turn of the steel strip overlaps with the previous turn at the spiral seam and is pressed together under the tension force. The steel strip is wound from one end of the prefabricated insulation pipe to the other end, and is fixed by welding at the end of the winding, thus forming an inner fixed pipe 5 outside the rigid insulation layer 2 and the reflective layer 4. At the same time, it is necessary to ensure that after the inner fixed pipe 5 presses the soft insulation layer 3, the thickness of the soft insulation layer 3 meets the design thickness requirements.

[0061] Step 4: Insert the prefabricated insulation pipe into the outer protective pipe 7, maintain the gap between the inner fixed pipe 5 and the outer protective pipe 7, and inject foaming material into the gap to form a foam layer 6.

[0062] Specifically, the gap between the inner fixed tube 5 and the outer protective tube 7 is maintained by a fixing block, and polyurethane foam is injected into the gap using a polyurethane foaming machine with or without a support to form a rigid polyurethane foam layer 6.

[0063] Step 5: Reserve spaced fixed pipe supports 9 on the surface of the outer protective pipe 7 so as to fix it to the concrete support pier at the installation site.

[0064] Specifically, fixed pipe supports 9 are set at certain intervals on the surface of the outer protective pipe 7 corresponding to the calcium silicate support ring inside the inner fixed pipe 5, and the distance between adjacent fixed pipe supports 9 is equal to the distance between the concrete support piers at the installation site.

[0065] In addition, about 150mm to 250mm from both ends of the working steel pipe 1, there are bare pipe sections 10 without covering the rigid insulation layer 2, soft insulation layer 3, reflective layer 4, inner fixed pipe 5, foam layer 6 and outer protective pipe 7. After welding is completed on the construction site, the bare pipe sections 10 at the joint are then covered.

[0066] Therefore, prefabricated insulated pipes facilitate on-site construction and enable the rapid and high-quality installation of thermal pipelines.

[0067] The above embodiments merely illustrate the basic principles and characteristics of the present invention. The present invention is not limited to the above embodiments. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite precast overhead thermal insulation pipe with a broken bridge, characterized in that, The utility model provides a kind of heat preservation pipe, including working steel pipe (1), several hard thermal insulation layers (2) are provided on the working steel pipe (1) in axial interval, several soft thermal insulation layers (3) are provided between two adjacent interval hard thermal insulation layers (2), and the surface of each soft thermal insulation layer (3) is provided with reflective layer (4), the surface of each hard thermal insulation layer (2) and outermost reflective layer (4) is provided with inner fixed pipe (5), the surface of inner fixed pipe (5) is provided with foaming layer (6), and the surface of foaming layer (6) is provided with outer protective tube (7);The inner fixed pipe (5) is spirally wound on the surface of hard thermal insulation layer (2) and reflective layer (4) with strip steel, and is fixed into shape, so that the hard thermal insulation layer (2) is closely attached to the inner surface of strip steel, and the thickness of soft thermal insulation layer (3) is compressed by 5%;The surface of outer protective tube (7) is provided with several fixed pipe supports (9) in axial interval, and the interval of adjacent fixed pipe supports (9) is adjustable, and the fixed pipe support (9) is arranged at the position corresponding to the hard thermal insulation layer (2).

2. The composite precast bridge-closed thermal insulation overhead pipe according to claim 1, characterized in that, The hard thermal insulation layer (2) includes a support ring made of microporous calcium silicate material, the inner ring surface of the support ring is in contact with the outer wall of the working steel pipe (1), and the outer ring surface of the support ring is in contact with the inner wall of the inner fixed pipe (5).

3. The composite precast bridge-closed thermal insulation overhead pipe according to claim 2, characterized in that, The support rings are stacked in the radial direction of the working steel pipe (1), and the reflective layer (4) is also arranged between two adjacent stacked support rings.

4. The composite precast bridge-closed thermal insulation overhead pipe according to claim 1, characterized in that, The soft thermal insulation layer (3) is made of thermal insulation cotton, and the reflective layer (4) is made of aluminum foil fiber cloth.

5. The composite precast bridge-closed thermal insulation overhead pipe according to claim 1, characterized in that, The entire surface of the working steel pipe (1) is wrapped with nano aerogel (8).

6. The composite bridge-cut-off and heat-insulated precast overhead insulated pipe according to claim 1, characterized in that, The outer protective tube (7) is spirally rolled into a cylindrical shape with a strip-shaped steel plate.

7. A method for manufacturing a composite precast overhead thermal insulation pipe with a thermal bridge break, based on the composite precast overhead thermal insulation pipe with a thermal bridge break according to any one of claims 1-6, characterized in that, The utility model includes the following steps: Step one, grinding and polishing the inner and outer surfaces of the working steel pipe (1), and coating a corrosion-resistant layer on the outer surface of the working steel pipe (1); Step two, arranging hard thermal insulation layers (2) on the surface of the working steel pipe (1) in axial interval, and alternately winding soft thermal insulation layers (3) between adjacent hard thermal insulation layers (2), and winding reflective layers (4) on the surface of each soft thermal insulation layer (3); Step three, spirally winding strip steel on the outer surface of the hard thermal insulation layer (2) and the outermost reflective layer (4) to form an inner fixed pipe (5), and compressing the hard thermal insulation layer (2) and the soft thermal insulation layer (3) to obtain a prefabricated thermal insulation pipe; Step four, inserting the prefabricated thermal insulation pipe into the outer protective tube (7), maintaining the gap between the inner fixed pipe (5) and the outer protective tube (7), and injecting foaming material into the gap to form a foaming layer (6); Step five, arranging fixed pipe supports (9) on the surface of the outer protective tube (7) in advance to facilitate fixation with concrete support piers at the installation site.

8. The method of claim 7, wherein the method further comprises: The working steel pipe (1) has a light pipe section (10) at both ends without being wrapped with hard thermal insulation layers (2), soft thermal insulation layers (3), reflective layers (4), inner fixed pipes (5), foaming layers (6), and outer protective tubes (7), and the light pipe section (10) is wrapped after welding at the construction site.

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