Multi-stage thermal bridge conduction type combined heat rod

Abstract

This application relates to the field of roadbed protection technology in permafrost areas, and discloses a multi-stage thermal bridge conductive combined heat pipe, including at least two heat pipe sections. Each heat pipe section has a quick-connect coupling fixedly installed at both ends. Adjacent heat pipe sections are joined together via the quick-connect coupling and butt-welded using a clamp-type pipe welding machine. The internal cavities of adjacent heat pipe sections are interconnected. Each heat pipe section includes: an evaporation section, used to penetrate deep into the permafrost area beneath the roadbed, filled with refrigerant and with heat dissipation fins on its outer wall; and a heat dissipation section, corresponding to the vertical condensation heat dissipation section of an "L"-shaped heat pipe, or the upper heat dissipation part of an extra-long heat pipe, with condensation fins on its outer wall. This solves the transportation problems of extra-long heat pipes and "L"-shaped heat pipes: through the segmented design, the length of each heat pipe section can be flexibly adjusted according to the cargo box size of freight vehicles, eliminating the need for special equipment during transportation and reducing transportation costs and risks.

Description

Technical Field

[0001] This invention relates to the field of roadbed protection technology for road engineering in permafrost regions, specifically to a multi-stage thermal bridge conductive combined heat pipe. Background Technology

[0002] In high-altitude permafrost regions, wide roadbeds have large cross-sectional dimensions and extensive heat-receiving areas. Furthermore, the dark color of the pavement significantly increases its heat absorption capacity, making it highly susceptible to melting of the underlying permafrost layer and threatening roadbed stability. Existing technologies commonly use heat pipes for protection, but traditional heat pipes are often installed vertically or at an angle at the slope toe, making it difficult for the evaporation section to extend to the center of the roadbed. This results in gaps in thermal stability maintenance of the permafrost in the center and on both sides of the roadbed, easily leading to the formation of a thaw plate at the upper limit of the underlying permafrost. This thaw plate gradually expands during long-term freeze-thaw cycles, exacerbating water accumulation on the frozen layer and further compromising roadbed stability.

[0003] To cover the central area of ​​the roadbed for thermal stability maintenance, the project uses extended heat pipes or "L"-shaped heat pipes (with a vertical upper condensation and heat dissipation section and an inclined lower evaporation section, with an angle between the two of 15° and 70°). However, existing heat pipes are all single, factory-installed integral structures. After the parts are processed, assembled, inspected, refrigerant-filled, and performance tested in the factory, they are transported to the site as a whole and installed by drilling. This integral structure is suitable for small, short-length heat pipes that are installed vertically or at a small angle. However, for extra-long heat pipes that exceed the length of a freight truck's cargo box and for "L"-shaped heat pipes with special structures, there are technical difficulties such as transportation and complex on-site installation, which seriously limits their application in the thermal stability maintenance of wide roadbeds.

[0004] Therefore, there is an urgent need for a heat pipe structure that can be transported in sections, quickly assembled on site, and ensures heat transfer efficiency and sealing performance, in order to solve the transportation and installation problems of ultra-long and "L"-shaped heat pipes and achieve effective freezing and maintenance of permafrost under the entire cross-section of wide roadbeds. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a multi-stage thermal bridge conductive combined heat pipe, which solves the problems of difficult transportation and inconvenient installation of existing ultra-long heat pipes and "L"-shaped heat pipes.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a multi-stage thermal bridge conductive combined heat pipe, comprising at least two heat pipe sections, wherein both ends of the heat pipe sections are fixedly installed with open and close quick connectors, adjacent heat pipe sections are connected by open and close quick connectors and fixed by butt welding with a clamp-type pipe welding machine, and the inner cavities between adjacent heat pipe sections are interconnected.

[0007] The heat pipe sections include:

[0008] The evaporation section is segmented and used to penetrate deep into the permafrost area beneath the roadbed. It is filled with refrigerant and has heat-dissipating fins on the outer wall.

[0009] The heat dissipation section is segmented, corresponding to the vertical condensation heat dissipation section of the "L"-shaped heat pipe, or the upper heat dissipation part of the extra-long heat pipe, with condensation fins on the outer wall.

[0010] The ground-mounted auxiliary section is installed on top of the heat dissipation section for protection and auxiliary heat dissipation.

[0011] Preferably, the opening and closing quick connector includes a male connector and a female connector. The male connector has an external thread on its outer side, and the female connector has a matching internal thread on its inner side. A sealing groove is formed on the mating surface of the male connector and the female connector. A sealing gasket is installed inside the sealing groove. The sealing gasket is made of low-temperature resistant fluororubber.

[0012] Preferably, the weld between adjacent hot rod sections is a continuous annular weld, and a polyethylene anti-corrosion sealing sleeve is fitted on the outside of the continuous annular weld, the thickness of the anti-corrosion sealing sleeve being not less than 3mm.

[0013] Preferably, the refrigerant is R134a or other low-temperature refrigerants suitable for environments ranging from -50°C to 30°C.

[0014] Preferably, the outer diameter of the evaporation section and the heat dissipation section is 80-120 mm, the thickness of the heat dissipation fins and the condensation fins is 1-3 mm, and the spacing between the fins is 30-100 mm.

[0015] Preferably, the heat pipe section further includes a corner section, the included angle of the axis of the corner section is 15 to 70°, the inner wall of the corner section is provided with a guide groove, and the opening and closing quick connectors are respectively installed at both ends of the corner section.

[0016] Preferably, the length of a single section of the heat pipe is between 0.5m and 7m.

[0017] Working principle: This combined heat pipe system comprises at least two heat pipe sections, which include an evaporation section, a heat dissipation section, and above-ground auxiliary sections, wherein:

[0018] (1) Evaporation section segment: used to penetrate deep into the permafrost area under the roadbed. It is filled with refrigerant and has heat dissipation fins on the outer wall (to enhance heat exchange with the permafrost).

[0019] (2) Heat dissipation section segment: The vertical condensation heat dissipation section corresponding to the "L"-shaped heat rod, or the upper heat dissipation part of the extra-long heat rod, is provided with condensation fins on the outer wall (to improve the heat exchange efficiency with the air).

[0020] (3) Ground-mounted auxiliary section: installed on the top of the heat dissipation section for protection and auxiliary heat dissipation.

[0021] 2. Segmented connection structure

[0022] (1) Each section of the heat pipe is fixedly installed with a quick-connect coupling at both ends. The quick-connect coupling includes a male coupling and a female coupling. The mating surfaces of the male coupling and the female coupling are provided with a sealing gasket (made of low-temperature resistant fluororubber). The male coupling has an external thread on the outside and the female coupling has a matching internal thread on the inside.

[0023] (2) Adjacent hot rod sections are connected to the female connectors via male connectors and then pre-fixed by threads to ensure that the inner cavities between sections are connected (to ensure that the refrigerant circulation channel is unobstructed).

[0024] (3) The pipe wall joints of adjacent hot rod sections are welded using a clamp-type pipe welding machine. The weld is a continuous annular weld. After welding, an anti-corrosion sealing sleeve (made of polyethylene with a thickness of not less than 3mm) is installed on the outside of the weld.

[0025] 3. Special design of the "L"-shaped combined heat pipe

[0026] For the "L"-shaped multi-stage thermal bridge conductive combined heat pipe, a corner section is set, and an openable quick connector is installed at both ends of the corner section. The included angle of the axis of the corner section is 15 to 70° (to adapt to different roadbed slope inclination requirements). The inner wall of the corner section is provided with a flow guide groove (to guide the flow of refrigerant and avoid local liquid accumulation affecting heat transfer).

[0027] 4. Segmented processing and assembly process

[0028] (1) Each heat pipe section is independently processed, assembled, sealed, charged with refrigerant and tested for thermal performance in the factory to ensure that the performance of each section meets the standards;

[0029] (2) After the sections are transported to the construction site, holes are first drilled at the preset positions on the roadbed using drilling equipment (the hole diameter is 5-10 mm larger than the outer diameter of the heat pipe section). Then, the evaporation section sections are installed in sequence, and fixed and welded together by opening and closing quick connectors.

[0030] (3) After the evaporation section is installed, the corner section (applicable to the “L” type structure) and the heat dissipation section are pre-fixed and welded through quick connectors. Finally, the ground auxiliary section is installed to complete the overall assembly.

[0031] This invention provides a multi-stage thermal bridge conductive combined heat pipe. It has the following beneficial effects:

[0032] 1. This invention solves the transportation problems of extra-long heat pipes and "L"-shaped heat pipes: through the segmented design, the length of each heat pipe segment can be flexibly adjusted according to the cargo box size of the freight vehicle, and no special equipment is required during transportation, reducing transportation costs and risks.

[0033] 2. This invention simplifies on-site installation: The segmented structure can be quickly connected on-site via openable and closed quick connectors, and can achieve efficient welding with a clamp-type pipe welding machine, eliminating the need for large installation equipment and adapting to the complex construction environment of high-altitude permafrost areas.

[0034] 3. This invention ensures heat transfer efficiency and sealing performance: the openable quick-connect coupling ensures the continuity of the internal cavity of the sections, and the refrigerant circulation is not affected. The annular continuous weld and anti-corrosion sealing sleeve ensure the structural sealing performance and avoid refrigerant leakage. At the same time, the low-temperature resistant sealing gasket is suitable for the extreme low temperature environment (-50℃~30℃) in the frozen soil area.

[0035] 4. This invention is suitable for the full-section maintenance needs of wide roadbeds: by combining to form an ultra-long or "L" shaped structure, the evaporation section can penetrate deep into the central area of ​​the roadbed, filling the gap in the thermal stability maintenance of traditional heat pipes, effectively inhibiting the formation of melting plates, and ensuring the long-term stability of the roadbed.

[0036] 5. The invention has a highly flexible structure: the number, length and turning angle of the heat pipe sections can be flexibly adjusted according to the roadbed width, frost depth and slope inclination to adapt to the needs of different engineering scenarios. Attached Figure Description

[0037] Figure 1 This is a diagram illustrating the ultra-long multi-stage thermal bridge conductive combined heat pipe of the present invention;

[0038] Figure 2 This is one of the exploded views of the ultra-long multi-stage thermal bridge conductive combined heat pipe in this invention;

[0039] Figure 3 The second exploded view of the ultra-long multi-stage thermal bridge conductive combined heat pipe in this invention;

[0040] Figure 4 This is a cross-sectional view of the "L"-shaped multi-stage thermal bridge conductive combined heat pipe in this invention;

[0041] Figure 5 This is a split view of the "L"-shaped multi-stage thermal bridge conductive combined heat pipe in this invention;

[0042] Figure 6 This is an exploded view of the "L"-shaped multi-stage thermal bridge conductive combined heat pipe in this invention;

[0043] Figure 7 This is a diagram illustrating the opening and closing quick connector of the present invention;

[0044] Figure 8 This is a schematic diagram of the opening and closing quick connector in this invention;

[0045] Figure 9 This is one of the exploded views of the opening and closing quick connector in this invention;

[0046] Figure 10 This is the second exploded view of the opening and closing quick connector in this invention;

[0047] Figure 11 This is a schematic diagram of the installation of the multi-stage thermal bridge conductive combined heat pipe in this invention.

[0048] The components are as follows: 1. Evaporation section; 2. Heat dissipation section; 3. Ground auxiliary section; 4. Open / close quick connector; 5. Male connector; 6. Female connector; 7. Circular continuous weld; 8. Anti-corrosion sealing sleeve; 9. Corner section; 10. Fin; 41. Male connector body; 42. External thread; 43. Sealing groove; 51. Female connector body; 52. Internal thread; 53. Sealing surface; 54. External connector. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Please see the appendix Figure 1 - Appendix Figure 11 The present invention provides a multi-stage thermal bridge conductive combined heat pipe, including at least two heat pipe sections. The two ends of the heat pipe sections are fixedly installed with open and close quick connectors 4. Adjacent heat pipe sections are connected by open and close quick connectors 4 and fixed by butt welding with a clamp-type pipe welding machine. The inner cavities between adjacent heat pipe sections are connected.

[0051] The heat pipe is segmented into sections including:

[0052] The evaporation section 1 is used to penetrate deep into the permafrost area beneath the roadbed. Its interior is filled with refrigerant and its outer wall is equipped with heat dissipation fins 10.

[0053] The heat dissipation section is divided into 2 sections, corresponding to the vertical condensation heat dissipation section of the "L"-shaped heat pipe, or the upper heat dissipation part of the extra-long heat pipe, and the outer wall is provided with condensation fins 10.

[0054] The ground-mounted auxiliary section 3 is installed on top of the heat dissipation section 2 for protection and auxiliary heat dissipation.

[0055] The quick-connector 4 includes a male connector 5 and a female connector 6. The male connector 5 has an external thread 42 on its outer side, and the female connector 6 has a matching internal thread 52 on its inner side. The mating surfaces of the male connector 5 and the female connector 6 have a sealing groove 43. A sealing gasket is installed inside the sealing groove 43. The sealing gasket is made of low-temperature resistant fluororubber.

[0056] The weld seam between adjacent hot bars is a continuous annular weld seam 7. A polyethylene anti-corrosion sealing sleeve 8 is fitted on the outside of the continuous annular weld seam 7. The thickness of the anti-corrosion sealing sleeve 8 is not less than 3mm.

[0057] The refrigerant is R134a or other low-temperature refrigerants suitable for environments ranging from -50℃ to 30℃.

[0058] The outer diameter of the evaporation section 1 and the heat dissipation section 2 is 80-120 mm, the thickness of the heat dissipation fins 10 and the condensation fins 10 is 1-3 mm, and the spacing between the fins 10 is 30-100 mm.

[0059] The length of a single section of the heat pipe ranges from 0.5m to 7m.

[0060] For details, please refer to the appendix. Figure 7 Appendix Figure 8 Appendix Figure 9 and appendix Figure 10 The male connector 5 of the openable quick connector 4 includes a male connector body 41, with an external thread 42 on the outside of the male connector body 41 and a sealing groove 43 (with a built-in sealing gasket) at the end. The female connector 6 includes a female connector body 51, with an internal thread 52 on the inside of the female connector body 51 and a sealing surface 53 at the end that is adapted to the sealing gasket. The male connector 5 and the female connector 6 are connected by threaded screwing. The external connector 54 is welded to the heat rod in sections.

[0061] The following description is based on specific examples:

[0062] Example 1: Extra-long multi-stage thermal bridge conductive combined heat pipe

[0063] Please see the appendix Figure 1 Appendix Figure 2 and appendix Figure 3 The implementation site of this embodiment is a high-altitude permafrost area with a roadbed width of 25m. It is necessary to use an ultra-long heat pipe with a length of 12m to maintain the permafrost under the center of the roadbed.

[0064] 1. Sectional design of heat pipe: The 12m ultra-long heat pipe is divided into 3 sections, each 4m long (adapted to the cargo box size of freight trucks), including two evaporation section sections 1 (total length 8m) and one heat dissipation section section 2 (length 3m), and an additional 0.5m long ground-mounted auxiliary section 3;

[0065] 2. Segmented processing: Each segment is processed in the factory. The outer wall of the evaporator segment 1 is welded with heat dissipation fins 10 with a thickness of 2mm and a spacing of 50mm. The outer wall of the heat dissipation segment 2 is welded with condensation fins 10 with a thickness of 2mm and a spacing of 80mm. The inside is filled with R134a refrigerant and passes the sealing test (pressure 0.8MPa, pressure holding for 24h without leakage) and thermal performance test (thermal conductivity ≥1000W / (m・K)).

[0066] 3. On-site installation: Drill holes (110mm diameter) at the pre-set positions on the roadbed, and insert the two evaporation section segments 1 into the holes in sequence. Connect them with the quick-connect couplings 4, and after pre-fixing by screwing in the threads, weld the circumferential weld using a clamp-type pipe welding machine. Fit the outside of the weld with a 3mm thick polyethylene anti-corrosion sealing sleeve 8. Then connect the heat dissipation section segment 2 and the above-ground auxiliary segment 3 with the quick-connect couplings 4, and repeat the connection, welding and anti-corrosion treatment steps.

[0067] 4. Effect verification: After installation, the heat pipe evaporation section penetrates deep into the permafrost layer below the center of the roadbed. Monitoring shows that the temperature of the permafrost in the center of the roadbed is stable at -3℃ to -1℃, with no thawing plate forming, and the roadbed settlement is controlled within 5mm / year, meeting the stability requirements.

[0068] Example 2: "L"-shaped multi-stage thermal bridge conductive combined heat pipe

[0069] The features that are the same as those in Embodiment 1 will not be repeated in this embodiment. The different features are as follows:

[0070] The heat pipe section also includes a corner section 9, the included angle of the axis of the corner section 9 is 15 to 70°, the inner wall of the corner section 9 is provided with a guide groove, and the openable and closable quick connectors 4 are respectively installed at both ends of the corner section 9.

[0071] Please see the appendix Figure 4 Appendix Figure 5 and appendix Figure 6 The implementation site of this embodiment is a permafrost area with a wide roadbed slope angle of 45°. It is necessary to use "L"-shaped heat pipes (the evaporation section has the same inclination angle as the slope, and the condensation section is vertical) for maintenance. The total length of the heat pipe sections is 10m, of which the evaporation section 1 is 7m long, the heat dissipation section 2 is 2.5m long, and the corner section 9 has a corner angle of 45°.

[0072] 1. Heat pipe segment design: It is divided into evaporation section 1 (7m, 1 section), corner section 9 (0.5m, axial angle 45°), heat dissipation section 2 (2.5m, 1 section) and ground auxiliary section 3 (0.3m). Each heat pipe section is equipped with a quick-connect coupling 4 at both ends.

[0073] 2. Segmented processing: The inner wall of the corner segment 9 is processed with a spiral guide groove with a width of 10mm and a depth of 5mm. The remaining heat rods are processed in the same way as in Example 1. After passing the sealing test (pressure 0.8MPa, pressure holding for 24h without leakage) and thermal performance test (thermal conductivity ≥1000W / (m・K)), the heat rods are transported in segments.

[0074] 3. On-site installation: Drill holes from the toe of the roadbed slope to the center area (100mm diameter for inclined sections and 90mm diameter for vertical sections). First, install the evaporation section segment 1, then connect the corner segment 9 (ensure that the included angle of the axis is consistent with the slope inclination angle), and finally connect the heat dissipation section segment 2 and the above-ground auxiliary segment 3 to complete the connection, welding and anti-corrosion treatment.

[0075] 4. Effect verification: Monitoring shows that the underlying frozen soil in the center and on both sides of the roadbed remains frozen, the amount of water accumulation on the frozen layer is reduced by 80%, and the stability of the roadbed is significantly improved.

[0076] Please see the appendix Figure 11 When the multi-stage thermal bridge conductive combined heat pipe provided by the present invention is installed, its evaporation section 1 extends into the permafrost layer below the central area of ​​the wide roadbed, and the heat dissipation section 2 extends vertically upward to the outside of the wide roadbed, covering the blank area of ​​traditional heat pipe maintenance and effectively inhibiting the formation of melting plate.

[0077] In summary, the multi-stage thermal bridge conductive combined heat pipe provided by this invention features a segmented design that allows for flexible adjustment of the heat pipe segment length according to the cargo box size of the transport vehicle, eliminating the need for special equipment and thus reducing the transportation costs and risks associated with ultra-long heat pipes and "L"-shaped heat pipes. During on-site installation, the segmented structure can be quickly connected via openable and closable quick connectors 4, and efficient welding can be achieved with a clamp-type pipe welding machine, eliminating the need for large equipment and adapting to the complex construction environment of high-altitude permafrost regions. Simultaneously, the openable and closable quick connectors 4 ensure the continuity of the internal cavities of each segment, without affecting refrigerant circulation. The annular continuous weld 7 and the anti-corrosion sealing sleeve 8 guarantee structural sealing, preventing leakage, and the low-temperature resistant sealing gasket can adapt to extreme low-temperature environments ranging from -50℃ to 30℃. By combining to form ultra-long or "L"-shaped structures, the evaporation section can penetrate deep into the central area of ​​the roadbed, effectively inhibiting the formation of melting plates and ensuring the long-term stability of the roadbed. Furthermore, this structure is highly flexible, allowing adjustment of the number, length, and turning angle of segments according to the roadbed width, permafrost depth, and slope inclination, adapting to the needs of different engineering scenarios.

[0078] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-stage thermal bridge conductive combined heat pipe, comprising at least two heat pipe sections, characterized in that, The two ends of the heat rod section are fixedly installed with open and close quick connectors (4). Adjacent heat rod sections are connected by open and close quick connectors (4) and fixed by clamp-type pipe welding machine. The inner cavities of adjacent heat rod sections are connected. The heat pipe sections include: The evaporation section (1) is used to penetrate into the permafrost area under the roadbed. It is filled with refrigerant and has heat dissipation fins (10) on the outer wall. The heat dissipation section is divided into sections (2), corresponding to the vertical condensation heat dissipation section of the "L"-shaped heat rod, or the upper heat dissipation part of the ultra-long heat rod, and the outer wall is provided with condensation fins (10). The ground-mounted auxiliary section (3) is installed on top of the heat dissipation section section (2) for protection and auxiliary heat dissipation.

2. The multi-stage thermal bridge conductive combined heat pipe according to claim 1, characterized in that, The opening and closing quick connector (4) includes a male connector (5) and a female connector (6). The male connector (5) has an external thread (42) on its outer side and a matching internal thread (52) on its inner side. A sealing groove (43) is provided on the mating surface of the male connector (5) and the female connector (6). A sealing gasket is installed inside the sealing groove (43). The sealing gasket is made of low-temperature resistant fluororubber.

3. The multi-stage thermal bridge conductive combined heat pipe according to claim 1, characterized in that, The weld seam between adjacent hot rod sections is a continuous annular weld seam (7), and a polyethylene anti-corrosion sealing sleeve (8) is fitted on the outside of the continuous annular weld seam (7), and the thickness of the anti-corrosion sealing sleeve (8) is not less than 3mm.

4. The multi-stage thermal bridge conductive combined heat pipe according to claim 1, characterized in that, The refrigerant is R134a or other low-temperature refrigerants suitable for environments ranging from -50℃ to 30℃.

5. The multi-stage thermal bridge conductive combined heat pipe according to claim 1, characterized in that, The outer diameter of the evaporation section (1) and the heat dissipation section (2) is 80-120 mm, the thickness of the heat dissipation fins (10) and the condensation fins (10) is 1-3 mm, and the spacing between the fins (10) is 30-100 mm.

6. The multi-stage thermal bridge conductive combined heat pipe according to claim 1, characterized in that, The heat pipe section also includes a corner section (9), the included angle of the axis of the corner section (9) is 15 to 70°, the inner wall of the corner section (9) is provided with a flow guide groove, and the opening and closing quick connector (4) is respectively installed at both ends of the corner section (9).

7. The multi-stage thermal bridge conductive combined heat pipe according to claim 1, characterized in that, The length of each section of the heat pipe is between 0.5m and 7m.

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