Coalfield fire area gravity heat pipe cooling and extinguishing device and method
By employing the lightweight design and oxygen-sealing technology of gravity heat pipe devices, the construction challenges in coalfield fire zones have been solved, enabling long-term and efficient cooling and fire extinguishing of fire zones. This solution is adaptable to complex terrain and remote areas, providing an efficient coalfield fire zone management solution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA COAL TECH & ENG GRP CHONGQING RES INST CO LTD
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-09
AI Technical Summary
Existing cooling and extinguishing devices and methods for coalfield fire zones suffer from high construction costs, low efficiency, poor applicability, and inability to provide long-term effective cooling and extinguishing. They are particularly difficult to implement in remote areas, and existing methods cannot completely isolate the air from the fire zone, making reignition easy.
The gravity heat pipe device includes an evaporation section, an insulation section, a condensation section, a fixing device, an oxygen barrier unit, and a monitoring unit. It utilizes the phase change heat transfer of the gravity heat pipe, and is installed through drilling and sealed to isolate oxygen, thereby realizing the heat export from deep fire zones. Combined with a lightweight design and a monitoring unit, it is suitable for construction in complex terrain and remote areas.
It achieves long-term and efficient cooling and fire suppression in fire zones, adapts to complex terrain and remote areas, has good sealing properties to prevent air infiltration, reduces operation and maintenance costs, and meets the sustainability and safety requirements of coalfield fire zones.
Smart Images
Figure CN122169865A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coalfield fire prevention and control technology, and relates to a gravity heat pipe cooling and extinguishing device and method for coalfield fire zones. Background Technology
[0002] Coalfield fire zones are a major hazard caused by coal seams exposed at shallow depths, continuously leaking air, supplying oxygen, and storing heat. They not only waste vast amounts of coal resources but also release toxic and harmful gases, polluting the atmosphere, encroaching on land resources, damaging ecosystems, triggering geological disasters, and threatening the lives and property of surrounding people and the stability of the ecological environment. Coalfield fire zones are mostly distributed deep underground or within coal gangue deposits, characterized by large areas, high concealment, rapid fire spread, great difficulty in control, and a high risk of reignition, posing a significant challenge to fire zone management. Currently, the core strategy for coalfield fire zone management is to cut off the combustion chain, namely, cooling, oxygen isolation, and inhibiting oxidation.
[0003] Currently, the main cooling and extinguishing devices and methods for coalfield fire zones have many shortcomings in practical applications: 1) Water injection method: This method requires injecting a large amount of water. When the water comes into contact with the high-temperature fire zone, it produces water vapor, which has a limited cooling effect and cannot continuously cool down and extinguish the fire.
[0004] 2) Grouting extinguishing method: The device requires a large amount of grouting material, resulting in high construction costs and long construction period; the grout is prone to solidification and blockage of the channel, making it difficult to penetrate deep into the fire zone, thus failing to achieve effective cooling and extinguishing of deep fire zones, easily forming "false extinguishing", and posing a high risk of reignition later.
[0005] 3) Covering and compaction method: It can only isolate the surface air and has no effect on the heat accumulation in the deep fire area; the cover layer is easily penetrated by air under complex terrain such as slopes, so the treatment effect is limited and it cannot be adapted to complex geological conditions.
[0006] 4) Inert gas injection method: The gas is easy to diffuse and lose, and the cost of maintaining the fire extinguishing effect is high; it cannot fundamentally reduce the temperature of the fire zone, and it is difficult to achieve complete control of the fire zone. It can only temporarily inhibit the oxidation of coal and cannot cut off the combustion chain.
[0007] 5) Stripping extinguishing method: The stripping extinguishing method is only suitable for fire areas with shallow fire sources and small areas. The applicable conditions are strict and it cannot be implemented in deep fire areas. Moreover, the construction process is complicated and inflexible. It requires large-scale earth stripping operations. The stripping process can easily disturb the fire area, allowing the originally smoldering coal seam to come into contact with sufficient air and intensify the combustion. It may also cause safety hazards. At the same time, the stripping operation will seriously damage the surface vegetation and soil structure, causing great ecological disturbance and high land restoration costs after treatment.
[0008] Furthermore, the remote locations of many coalfield fire zones make it difficult to carry out large-scale equipment construction, further increasing the difficulty and cost of cooling and extinguishing fires in these areas. Existing fire zone cooling devices and methods are limited by geographical and construction conditions, making them unsuitable for long-term and effective cooling and extinguishing. Summary of the Invention
[0009] In view of this, the purpose of the present invention is to provide a gravity heat pipe cooling and extinguishing device and method for coalfield fire areas, so as to improve the cooling and extinguishing efficiency of underground coal mine fire areas, reduce energy consumption, and achieve long-term effective fire extinguishing and cooling.
[0010] To achieve the above objectives, the present invention provides the following technical solution: A gravity heat pipe cooling and extinguishing device for coalfield fire zones includes a gravity heat pipe, a fixing device, a heat dissipation unit, an oxygen isolation unit, and a monitoring unit. Gravity heat pipes consist of an evaporation section, an insulation section, and a condensation section. The evaporation section corresponds to the interior of the fire zone, the insulation section corresponds to the overlying rock layer and surface layer of the fire zone, and the condensation section is the above-ground section and is connected to the heat dissipation unit. The anchoring device is used to secure the gravity heat pipe to the ground surface; The oxygen-barrier unit includes an oxygen-barrier sleeve fitted on the outside of the insulation section and a sealing filler layer filled between the oxygen-barrier sleeve and the gravity heat pipe to prevent air from seeping into the fire zone. The monitoring unit includes temperature sensors installed below the surface of the evaporation section, condensation section, and fire zone, as well as pressure sensors installed inside the oxygen isolation unit to monitor the sealing status.
[0011] Optionally, several annular heat exchange fins are provided on the outer side of the evaporation section.
[0012] Optionally, the bottom annular heat exchange fins are connected to soft metal sheets that can extend to the surface of the high-temperature coal body.
[0013] Optionally, the metal sheet has an anti-slip raised structure.
[0014] Optionally, the evaporation section is filled with a composite heat exchange medium, which is a mixture of naphthalene, biphenyl and thermally conductive silicone oil, and the ratio is adjusted according to the temperature of the fire zone.
[0015] Optionally, the fixing device includes a cross-shaped base that fits against the ground surface. The center of the base has a central hole that matches the gravity heat pipe. The four arms extending from the base are anchoring arms. The ends of the four anchoring arms away from the central hole have anchoring holes that match the anchor rods. The anchor rods anchor the fixing device to the ground surface through the anchoring holes.
[0016] Optionally, the anchoring arm is connected to a height adjustment device, which includes a slide rail assembly, a connecting rod, and a flexible element sleeved on the gravity heat pipe; the slide rail assembly includes a slide rail seat mounted on the base, a slide rail set on the slide rail seat, and a slider slidably connected to the slide rail; the slider is locked in position by bolts threaded onto it; the flexible element is hinged to the slider by the connecting rod, so that the installation height of the flexible element can be changed by adjusting the position of the slider on the slide rail.
[0017] Optionally, the slide rail assembly's slide rail seat is mounted on the base via a ball joint to allow for a certain angle of adjustment.
[0018] Optionally, one end of the connecting rod is hinged to the slider via a first pivot, and the other end is hinged to the flexible element via a second pivot.
[0019] Optionally, a clamp is provided on the outside of the flexible element to lock the flexible element in place.
[0020] Optionally, a sealing gasket is provided on the inner side of the flexible element.
[0021] Optionally, the heat dissipation unit includes a cold plate with internal flow channels, in which coolant flows under the drive of a pump, and the pump is connected to a solar power module.
[0022] Optionally, the outer side of the cold plate is equipped with a perforated protective cover to prevent external debris from affecting the heat dissipation effect.
[0023] Optionally, the outer wall of the condenser section is provided with fins to increase the contact area with air.
[0024] Optionally, the fins have a reflux channel with a hydrophilic surface, which is connected to the condensation section to guide the liquid to flow back quickly.
[0025] Optionally, the oxygen-barrier sleeve is made of high-temperature resistant and flame-retardant silicone; the sealing filler layer is a mixture of expanded graphite and flame-retardant clay.
[0026] Optionally, the oxygen barrier unit also includes an elastic sealing ring fitted onto the oxygen barrier sleeve and located between the fixing device and the ground surface.
[0027] Optionally, the evaporation section, the insulation section, and the condensation section can be integrally formed.
[0028] A method for cooling and extinguishing coalfield fires using gravity heat pipes, comprising the following steps: (The method includes the gravity heat pipe cooling and extinguishing device for coalfield fires as described above.) S1. Fire Zone Survey: Survey the fire zone's extent, depth, and temperature distribution; determine gravity heat pipe parameters, including length, aspect ratio, and filling rate, as well as the composite heat exchange medium ratio and spacing. S2. Drilling: Drill a hole at a predetermined location in the fire zone to the depth of the fire zone; S3. Installation: Insert the assembled gravity heat pipe into the borehole, positioning the evaporation section in the core area of the fire zone and the condensation section above the ground surface; then anchor the gravity heat pipe to the ground surface and seal the borehole to prevent oxygen ingress. S4. Monitoring: The monitoring unit monitors the fire zone temperature, heat pipe operating status, and sealing status in real time. S5. Maintenance: Regularly check the operating status of the cooling and extinguishing device based on monitoring data, and replenish or replace the working fluid and sealing materials until the fire is extinguished.
[0029] The beneficial effects of this invention are as follows: (1) Good continuity: By using gravity heat pipe phase change heat transfer, heat from deep fire zone can be continuously and efficiently discharged to the surface without external power. After the gravity heat pipe cooling and extinguishing device is completed, it can be used for long-term cooling of fire zone without the need for additional measures, thus fundamentally reducing coal temperature and cutting off the combustion chain. (2) Good adaptability: solves the construction problem in remote areas: the device adopts a lightweight and segmented design, and each component can be prefabricated and assembled. It is suitable for manual or small equipment construction, adapts to the working conditions of remote coalfield fire areas where it is not easy to carry out large equipment construction, solves the problem of large equipment entering the site in remote areas, and adapts to different terrains, expanding the applicability of the device. (3) Good sealing performance: The combination of elastic sealing ring and heat-expanding sealing filling layer can effectively adapt to geological deformation, completely isolate the fire zone from the air, prevent air from entering the fire zone, and prevent reignition; (4) Convenience of maintenance: Each component has a simple structure, reliable connection, and good sealing performance, which can effectively prevent air from seeping into the fire area and working fluid from leaking; the monitoring components are easy to operate, and staff can view the monitoring data on-site in real time or remotely. The maintenance workload is small and the cost is low. No professional maintenance team is required, which is suitable for the maintenance needs of remote areas.
[0030] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram of a gravity heat pipe cooling and fire extinguishing device; Figure 2 Schematic diagram of the fixing device Figure 1 ; Figure 3 Schematic diagram of the fixing device Figure 2 .
[0032] Reference numerals: 1. Metal sheet; 2. Annular heat exchange fin; 3. Evaporation section; 4. Insulation section; 5. Sealing filler layer; 6. Oxygen barrier sleeve; 7. Elastic sealing ring; 8. Fixing device; 9. Pressure sensor; 10. Condensation section; 11. Cold plate; 12. Fin; 13. Temperature display; 14. Temperature sensor; 15. Flexible element; 16. Base; 17. Fastening anchor; 18. Slide rail assembly; 19. Connecting rod; 20. Sealing gasket; 21. Ball joint; 22. Slide rail; 23. First rotating shaft; 24. Clamp; 25. Second rotating shaft. Detailed Implementation
[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0034] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.
[0035] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0036] Gravity heat pipes, as a highly efficient passive heat transfer element, are suitable for cooling and extinguishing fires in coalfield fire areas due to their advantages such as simple structure, low cost, high heat transfer limit, no secondary pollution, and ability to achieve long-distance passive heat transfer.
[0037] Example 1 Please see Figures 1-3 This is a gravity heat pipe cooling and extinguishing device for coalfield fire zones. The figure shows the following structure: 1. Metal sheet; 2. Annular heat exchange fins; 3. Evaporation section; 4. Insulation section; 5. Sealing and filling layer; 6. Oxygen barrier sleeve; 7. Elastic sealing ring; 8. Fixing device; 9. Pressure sensor; 10. Condensation section; 11. Cold plate; 12. Fins; 13. Temperature display; 14. Temperature sensor; 15. Flexible element; 16. Base; 17. Fastening anchor; 18. Slide rail assembly; 19. Connecting rod; 20. Sealing gasket; 21. Ball joint; 22. Slide rail; 23. First rotating shaft; 24. Clamp; 25. Second rotating shaft. This cooling and extinguishing device mainly includes a gravity heat pipe, a fixing device, a heat dissipation unit, an oxygen barrier unit, and a monitoring unit.
[0038] The gravity heat pipe includes an evaporation section 3, an insulation section 4, and a condensation section 10. The three sections are integrally formed and sealed together. The evaporation section 3 is located inside the fire zone, the insulation section 4 penetrates the overlying rock layer and the surface layer of the fire zone, and the condensation section 10 is located above the surface and connected to the high-efficiency heat dissipation unit.
[0039] The outer side of the evaporation section 3 is uniformly provided with several annular heat exchange fins 2, which are made of high-temperature and corrosion-resistant alloy material. The bottom annular heat exchange fins 2 are connected to soft metal sheets 1, which have anti-slip protrusions. The metal sheets 1 extend to the surface of the high-temperature coal body, increasing the contact area with the coal body, improving heat absorption efficiency, and enhancing the fit with the coal body to prevent the gravity heat pipe from loosening. The evaporation section 3 is filled with a composite heat exchange medium, which can be a mixture of high-temperature working fluids such as naphthalene, biphenyl, and thermally conductive silicone oil. The ratio can be adjusted according to the actual temperature of the fire zone to avoid working fluid failure and ensure long-term stable heat transfer. The gravity heat pipe is made of high-temperature and corrosion-resistant material and can withstand the high temperature and corrosive environment of the fire zone for a long time.
[0040] Aluminum or copper fins 12 are attached to the outer wall of the condensing section 10 to increase the contact area with air. Fins are added inside the condensing section 10 to increase the contact with the heat exchange medium. The fins 12 have a return flow channel communicating with the condensing section 10. The return flow channel is designed with a hydrophilic surface to guide rapid return flow.
[0041] The fixing device 8 is used to fix the gravity heat pipe. The fixing device 8 includes a cross-shaped base 16, which is set against the ground surface. The center of the base 16 has a central hole that matches the gravity heat pipe. Four long arms distributed around the fixing device 8 are anchoring arms. The end of each anchoring arm away from the central hole has an anchoring hole that matches an anchor rod. The anchor rod anchors the fixing device 8 to the ground surface through the anchoring holes. No large anchoring equipment is required; installation can be completed manually or with a small drilling rig, making it suitable for construction in remote locations. A height adjustment device is provided on the upper side of the anchoring arms. The height adjustment device includes a slide rail assembly 18, a connecting rod 19, and a flexible element 15, which can adjust the fixing height of the gravity heat pipe. The slide rail assembly 18 includes a slide rail seat mounted on a base 16 via a ball joint 21, a slide rail 22 disposed on the slide rail seat, and a slider slidably connected to the slide rail 22. The slide rail seat can be adjusted to a certain angle via the ball joint 21. The slider is locked in place by a bolt threaded onto it. One end of the connecting rod 19 is hinged to the slider via a first pivot 23, and the other end is hinged to the flexible element 15 via a second pivot 25. A sealing gasket 20 is provided on the inner side of the flexible element 15. After the bolt is loosened, the connecting rod 19 can move along the slide rail 22 of the slide rail assembly 18. As the connecting rod 19 moves on the slide rail 22, the height of the flexible element can be adjusted. After adjusting to a suitable position, the flexible element is locked by a clamp 24, thereby completing the fixation of the gravity heat pipe. The fixing device 8 of the present invention is a cross-anchoring structure with height adjustment, which is convenient for installation in complex terrain.
[0042] The heat dissipation unit includes a cold plate 11 and a protective cover. The cold plate 11 has flow channels inside, through which coolant (water) flows under the drive of a pump, carrying away heat. The water is taken from a nearby water source. The pump can be powered by a solar power module, eliminating the need for external large power supply equipment, making it suitable for remote areas without power grid coverage. The protective cover is located on the outside of the cold plate 11. The protective cover has a hollow structure, which combines dustproof, rainproof and protective functions, preventing external debris from affecting the heat dissipation effect.
[0043] The oxygen-barrier unit includes an oxygen-barrier sleeve 6, a sealing filling layer 5, and an elastic sealing ring 7. The oxygen-barrier sleeve 6 is located outside the insulated section 4 of the gravity heat pipe. The sealing filling layer 5 and the elastic sealing ring 7 are located between the fixing device 8 and the ground. The oxygen-barrier sleeve 6 is made of high-temperature resistant and flame-retardant silicone material, which can effectively prevent air from penetrating into the fire zone. The sealing filling layer 5 is filled between the oxygen-barrier sleeve 6 and the gravity heat pipe. The sealing filling layer 5 is made of a mixture of expanded graphite and flame-retardant clay. After being heated, it expands and can further enhance the sealing and oxygen-barrier effect, while also playing a buffering and shock-absorbing role to protect the heat pipe body.
[0044] The monitoring unit includes a temperature sensor 14 (platinum resistance thermometer), a pressure sensor 9, and a temperature display 13. The temperature sensor 14 (platinum resistance thermometer) is installed in the evaporation section 3, the condensation section 10 of the gravity heat pipe, and 0.5m below the ground surface in the fire zone, respectively, to monitor the temperature of the fire zone and the heat transfer status of the heat pipe in real time. The pressure sensor 9 is installed inside the oxygen-barrier sleeve 6 to monitor the sealing and oxygen-barrier effect and prevent air infiltration due to seal failure. The temperature display 13 is installed above the fixed device 8 and adopts a portable design. It can display monitoring data in real time and can upload data via network, adapting to the monitoring needs of remote areas.
[0045] The gravity heat pipe cooling and extinguishing device for coalfield fire areas is designed according to the fire area, terrain and temperature distribution. The heat pipe spacing is set as follows: the heat pipe spacing in the construction platform area (8) is set to 3~10m, and the heat pipe spacing in the sloping area is set to 2.5~6m to increase the effective temperature control radius of a single pipe and reduce the number of heat pipes.
[0046] Example 2 A method for cooling and extinguishing coalfield fires using gravity heat pipes includes the following steps: (1) Fire zone reconnaissance and fire source detection A detailed survey was conducted to determine the location, area, combustion depth, temperature distribution, and topographical conditions of the fire zone. Surface temperatures in the fire zone were measured, and isotherm maps were drawn. Based on the survey results, the length, aspect ratio, liquid filling rate, and composite heat exchanger ratio of the gravity heat pipes were determined. Simultaneously, the location and spacing of the multi-pipe arrangement were determined to ensure the device is adapted to the actual conditions of the fire zone.
[0047] (2) Components of the prefabrication device Based on the determined parameters, prefabricate gravity heat pipes, fixing devices, heat dissipation units, oxygen isolation units, and monitoring units to complete the assembly of each component.
[0048] (3) On-site installation A drilling rig is used to drill holes at a predetermined location in the fire zone. The drilling depth is determined according to the depth of the fire zone, ensuring that the bottom of the hole extends into the fire zone. The diameter of the hole is slightly larger than the diameter of the gravity heat pipe. The assembled gravity heat pipe is inserted into the hole, so that the evaporation section 3 is located in the core area of the fire zone, the insulation section 4 penetrates the hole, and the condensation section 10 is located above the ground surface. The annular heat exchange fins 2 of the evaporation section 3 are tightly attached to the coal body on the inner wall of the hole. The fixing device 8 is adjusted to ensure that the gravity heat pipe is firmly fixed. The installation can be completed manually or with small equipment, making it suitable for construction in remote areas.
[0049] (3) Sealing and oxygen-proof treatment: Adjust the elastic sealing ring 7 to fit tightly to the ground surface and adapt to complex terrain; fill the gap between the oxygen-proof sleeve 6 and the gravity heat pipe with a sealing filling layer to ensure that the sealing filling layer is filled tightly and achieves complete sealing after heating and expansion, thus preventing air from seeping into the fire zone.
[0050] (4) Monitoring component debugging Debug the monitoring components, start the pressure sensor 9 and temperature display 13, set the monitoring alarm threshold, and ensure that the monitoring data is accurate and the alarm function is normal.
[0051] (5) Long-term cooling and fire extinguishing When the gravity heat pipe is working, the evaporation section 3 absorbs heat from the core area of the fire zone through the annular heat exchange fins 2, causing the composite heat exchange medium to evaporate into steam. The steam rises along the heat pipe body to the condensation section 10, where it carries away the heat through the heat dissipation unit. After the steam condenses into liquid, it flows back to the evaporation section 3 under the action of gravity, completing the cycle of heat transfer and continuously reducing the temperature of the fire zone. Firefighters should promptly check the monitoring data, regularly inspect the operating status of the heat pipe and the sealing and oxygen-proof effect, and replenish the heat exchange medium and sealing materials. According to the temperature changes in the fire zone, the operating parameters should be adjusted to ensure long-term stable cooling and fire suppression.
[0052] (6) Post-maintenance Once the relevant parameters of the fire zone reach the standard for extinguishing the coalfield fire, the gravity heat pipe is recovered for long-term monitoring and ecological restoration.
[0053] This invention utilizes the passive and efficient heat transfer characteristics of gravity heat pipes to continuously and deeply reduce coal temperature, thereby extinguishing fires at their root. The device is lightweight, easy to construct, and suitable for remote and complex terrains. It is reliably sealed to prevent reignition. It has low operation and maintenance costs and is environmentally friendly, providing an efficient solution for coalfield fire control.
[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A gravity heat pipe cooling and extinguishing device for coalfield fire zones, characterized in that: Includes gravity heat pipe, fixing device (8), heat dissipation unit, oxygen isolation unit and monitoring unit; The gravity heat pipe includes an evaporation section (3), an insulation section (4) and a condensation section (10). The evaporation section (3) corresponds to the interior of the fire zone, the insulation section (4) corresponds to the overlying rock layer and surface layer of the fire zone, and the condensation section (10) is the above-ground section and is connected to the heat dissipation unit. The fixing device (8) is used to anchor the gravity heat pipe to the ground surface; The oxygen-barrier unit includes an oxygen-barrier sleeve (6) fitted outside the insulation section (4) and a sealing filling layer between the oxygen-barrier sleeve (6) and the gravity heat pipe to prevent air from penetrating into the fire zone. The monitoring unit includes a temperature sensor (14) installed in the evaporation section (3), the condensation section (10) and below the surface of the fire zone, and a pressure sensor (9) installed inside the oxygen isolation unit (6) to monitor the sealing status.
2. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: Several annular heat exchange fins (2) are provided on the outer side of the evaporation section (3).
3. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 2, characterized in that: The bottom annular heat exchange fins (2) are connected to soft metal sheets (1) that can extend to the surface of the high-temperature coal body.
4. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 3, characterized in that: The metal sheet (1) has an anti-slip protrusion structure.
5. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: The evaporation section (3) is filled with a composite heat exchange medium, which is a mixture of naphthalene, biphenyl and thermally conductive silicone oil, and its ratio is adjusted according to the temperature of the fire zone.
6. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: The fixing device (8) includes a cross-shaped base (16) that fits against the ground surface. The center of the base (16) has a central hole that matches the gravity heat pipe. The four arms extending from the base (16) are anchoring arms. The ends of the four anchoring arms away from the central hole have anchoring holes that match the anchor rods. The anchor rods anchor the fixing device (8) to the ground surface through the anchoring holes.
7. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 6, characterized in that: The anchoring arm is connected to a height adjustment device, which includes a slide rail assembly (18), a connecting rod (19), and a flexible element (15) sleeved on a gravity heat pipe. The slide rail assembly (18) includes a slide rail seat mounted on a base (16), a slide rail (22) set on the slide rail seat, and a slider slidably connected to the slide rail (22). The slider is locked in place by a bolt threaded onto it. The flexible element (15) is hinged to the slider through the connecting rod (19) so that the installation height of the flexible element (15) can be changed by adjusting the position of the slider on the slide rail (22).
8. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 7, characterized in that: The slide rail seat of the slide rail assembly (18) is mounted on the base (16) via a ball joint (21) to achieve a certain angle of adjustment.
9. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 7, characterized in that: One end of the connecting rod (19) is hinged to the slider via the first pivot (23), and the other end is hinged to the flexible element (15) via the second pivot (25).
10. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 7, characterized in that: The flexible element (15) is provided with a clamp (24) on the outside to lock the flexible element (15).
11. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 7, characterized in that: The flexible element (15) has a sealing gasket (20) on its inner side.
12. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: The heat dissipation unit includes a cold plate (11) with internal flow channels. Coolant flows in the flow channels under the drive of a pump, and the pump is connected to a solar power module.
13. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 12, characterized in that: The outer side of the cold plate (11) is provided with a perforated protective cover to prevent external debris from affecting the heat dissipation effect.
14. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: The outer wall of the condensation section (10) is provided with fins (12) to increase the contact area with air.
15. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 14, characterized in that: The fins (12) have a reflux channel with a hydrophilic surface, which is connected to the condensation section (10) to guide the liquid to reflux rapidly.
16. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: The oxygen-barrier sleeve (6) is made of high-temperature resistant flame-retardant silicone; the sealing filling layer (5) is a mixture of expanded graphite and flame-retardant clay.
17. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: The oxygen isolation unit also includes an elastic sealing ring (7) that is sleeved on the oxygen isolation sleeve (6) and located between the fixing device (8) and the ground surface.
18. The gravity heat pipe cooling and extinguishing device for coalfield fire zones according to claim 1, characterized in that: The evaporation section (3), the insulation section (4), and the condensation section (10) are integrally formed.
19. A method for cooling and extinguishing fires in coalfield fire zones using gravity heat pipes, characterized in that: The gravity heat pipe cooling and extinguishing device for coalfield fire zones as described in any one of claims 1 to 18 includes the following steps: S1. Fire Zone Survey: Survey the fire zone's extent, depth, and temperature distribution; determine gravity heat pipe parameters, including length, aspect ratio, and filling rate, as well as the composite heat exchange medium ratio and spacing. S2. Drilling: Drill a hole at a predetermined location in the fire zone to the depth of the fire zone; S3. Installation: Insert the assembled gravity heat pipe into the borehole, so that the evaporation section (3) is located in the core area of the fire zone and the condensation section (10) is located above the ground surface; then anchor the gravity heat pipe to the ground surface and seal the borehole to prevent oxygen from entering. S4. Monitoring: The monitoring unit monitors the fire zone temperature, heat pipe operating status, and sealing status in real time. S5. Maintenance: Regularly check the operating status of the cooling and extinguishing device based on monitoring data, and replenish or replace the working fluid and sealing materials until the fire is extinguished.