Improved multi-stage configuration super-long gravity heat pipe

Abstract

This invention discloses an improved multi-stage ultra-long gravity heat pipe, belonging to the technical field of ultra-long gravity heat pipes. The improved multi-stage ultra-long gravity heat pipe includes a heat pipe body, a support mechanism fixedly installed on the outer side of the heat pipe body, several steam pools fixedly installed on one side of the inner wall of the heat pipe body, and several two-phase flow mechanisms fixedly installed on the other side of the inner wall of the heat pipe body. A return liquid pipe extending into the two-phase flow mechanism is fixedly installed inside the heat pipe body. Each of the two-phase flow mechanisms includes a buffer pool and an overflow pipe. One side of the bottom of the buffer pool is fixedly connected to the top of the overflow pipe, and the bottom of the buffer pool has several open liquid tanks. By setting up two-phase flow mechanisms, the working fluid return is achieved by gravity, requiring no external power input. The heat transfer coefficient is higher than that of copper, and groundwater is not extracted, avoiding geological subsidence, brine scaling, water resource consumption, and the phenomenon of decreased or even failed heat transfer performance.

Description

Technical Field

[0001] This invention belongs to the field of ultra-long gravity heat pipe technology, specifically relating to an improved multi-stage ultra-long gravity heat pipe. Background Technology

[0002] Geothermal energy, as a clean and renewable energy source, has received increasing attention globally. To more efficiently extract and utilize geothermal energy, ultra-long gravity heat pipe circulation technology has emerged as a major innovation in the field. This advanced geothermal extraction technology utilizes the high-efficiency heat transfer characteristics of heat pipes, combined with gravity, to achieve continuous and stable geothermal energy extraction. This technology can significantly improve geothermal energy extraction efficiency and reduce extraction costs, laying the foundation for large-scale geothermal energy application. Ultra-long gravity heat pipes possess excellent heat transfer performance, rapidly transferring geothermal energy to the ground and improving extraction efficiency. The circulation method ensures the continuous utilization of geothermal resources and reduces environmental impact. Ultra-long gravity heat pipe circulation technology can reduce geothermal extraction costs, improve energy utilization efficiency, and bring considerable economic benefits to the geothermal industry.

[0003] However, when ultra-long gravity heat pipes exceed one kilometer in length, a deep pool of liquid working fluid forms at the bottom, causing a sharp increase in static pressure. According to the principle of phase equilibrium, the increased pressure leads to a rise in the saturation temperature of the working fluid, inhibiting the boiling phase change process in the evaporation section. This makes it difficult for the working fluid to vaporize at normal formation temperatures, severely hindering heat absorption and upward transport. This phenomenon directly results in a significant decrease in the overall heat transfer performance of the heat pipe, or even its failure, posing a serious challenge to this technology in deep geothermal development.

[0004] To alleviate the high static pressure problem, several improvement schemes have been proposed in existing technologies. One is to use a mixed working fluid, adjusting the saturation pressure curve by adding non-condensable gases to lower the initial boiling temperature. Another is to modify the structure by adding a guide tube or riser pipe inside the heat pipe, utilizing the gaseous working fluid to entrain the liquid working fluid and reduce the liquid column height. A third is to adopt a staged heating strategy, arranging multiple layers of casing along the evaporation section to achieve a stepped phase change of the working fluid. However, these schemes still have significant limitations in ultra-long heat pipes. The mixed working fluid method alters the transport properties of the working fluid, potentially leading to a decrease in circulation stability, and the optimal ratio is difficult to precisely control with well depth. The structural improvement method, on an ultra-long scale, results in a complex gas-liquid two-phase flow pressure drop model, easily inducing flow instability. The staged heating method, on the other hand, has extremely high requirements for manufacturing processes, significantly increasing engineering costs and making maintenance difficult. Summary of the Invention

[0005] The purpose of this invention is to provide an improved multi-stage ultra-long gravity heat pipe to solve the technical problem that when the length of the heat pipe exceeds one kilometer, a deep liquid working fluid pool is formed at the bottom, the static pressure increases significantly, inhibiting the boiling phase change of the working fluid in the evaporation section, leading to a decrease in heat transfer performance or even failure.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses an improved multi-stage configuration ultra-long gravity heat pipe, including a heat pipe body; The interior of the heat pipe body is provided with multiple steam pools and multiple two-phase flow mechanisms arranged axially; the steam pools and the two-phase flow mechanisms are arranged opposite to each other. The two-phase flow mechanism includes a buffer tank and an overflow pipe. One side of the bottom of the buffer tank is connected to the overflow pipe. The bottom of the buffer tank is provided with multiple open liquid tanks. The other side of the bottom of the buffer tank is connected to a distribution pipe extending into the open liquid tanks. The heat pipe body is also provided with a return pipe, which extends into the two-phase flow mechanism.

[0007] Furthermore, the liquid distribution pipe is equipped with multiple liquid level valves that extend into the corresponding open liquid tank.

[0008] Furthermore, the bottom end of the overflow pipe is connected to the interior of an adjacent buffer pool.

[0009] Furthermore, the bottom end of the return pipe is connected to the opposite buffer solution tank.

[0010] Furthermore, both the buffer solution pool and the open liquid tank are fixedly connected to the inner wall of the heat pipe body.

[0011] Furthermore, a support mechanism is provided on the outer side of the heat pipe body. The support mechanism includes multiple connecting rings and multiple reinforcing rings. Multiple length rods are installed on the outer side of the connecting rings. The ends of the length rods are connected to the corresponding reinforcing rings. Multiple reinforcing rods are provided between adjacent reinforcing rings.

[0012] Furthermore, the inner side of the connecting ring is fixedly connected to the heat pipe body.

[0013] This invention also discloses a working fluid circulation method based on the above-mentioned improved multi-stage configuration ultra-long gravity heat pipe, comprising the following steps: The working fluid is heated and evaporated at the bottom of the heat pipe body, forming a gaseous working fluid that rises to the steam pool and then condenses and releases heat. The condensed liquid working fluid flows back to the buffer pools of each stage through the return pipe. The liquid working fluid in the buffer pool is distributed to each open liquid tank through the distribution pipe, and then passed down through the overflow pipe in turn, eventually returning to the bottom of the heat pipe body, forming a multi-stage segmented circulation flow.

[0014] Furthermore, the liquid level of the liquid working medium in the open liquid tank is sensed and adjusted in real time by a level valve installed on the distribution pipe to control the distribution amount of working medium and the flow stability between each stage.

[0015] Furthermore, the two-phase flow and evaporation-condensation heat transfer process of the working fluid inside the heat pipe body are characterized using the Lee model.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses an improved multi-stage ultra-long gravity heat pipe. By arranging multiple two-phase flow mechanisms along the axial direction, consisting of buffer pools, overflow pipes, open liquid tanks, and distribution pipes, the traditional single-segment long liquid column is divided into multi-stage segmented liquid columns, fundamentally solving the technical problem of excessive static pressure at the bottom of ultra-long heat pipes inhibiting phase change. Specifically, each stage of the two-phase flow mechanism independently undertakes local working fluid circulation. The liquid working fluid is distributed to each open liquid tank via the distribution pipe and overflows naturally to the next stage by gravity, rather than relying on a single liquid column at the bottom to provide circulation driving force. This disperses the huge static pressure generated by the kilometer-long liquid column into controllable short liquid columns at each stage, effectively reducing the static pressure load at the bottom of the evaporation section and eliminating the inhibitory effect on the boiling phase change of the working fluid. Meanwhile, this scheme relies entirely on gravity for the gradual return and distribution of the working fluid, requiring no external power input, thus possessing inherent advantages such as extremely low energy consumption and low operation and maintenance costs. The heat transfer process is dominated by the latent heat of phase change, resulting in a significantly higher heat transfer coefficient than traditional metal pipes. Furthermore, it eliminates the need for groundwater extraction, avoiding environmental problems such as geological subsidence, brine scaling, and water resource consumption. In summary, this multi-stage configuration design, through a purely passive and segmented approach, systematically eliminates the high static pressure suppression effect caused by deep liquid working fluid pools, ensuring that the heat pipe maintains stable evaporation and condensation heat transfer performance even under deep burial conditions, effectively preventing the phenomenon of decreased or even failed heat transfer performance.

[0017] Furthermore, by installing level valves extending into each open liquid tank on the distribution pipe, real-time sensing and active adjustment of the liquid level in each open liquid tank are achieved. The advantage of this design is that it can dynamically distribute the working fluid flow rate according to the difference in evaporation intensity at each stage, avoiding static pressure accumulation due to excessively high local liquid levels or drying failure due to excessively low liquid levels, ensuring that each stage in the multi-stage configuration can operate within the optimal liquid level range, thereby improving the uniformity and stability of heat transfer throughout the pipe.

[0018] Furthermore, the bottom end of the overflow pipe is connected to the interior of the adjacent buffer tank, creating a clear interstage overflow path. Its advantage lies in the fact that when the liquid level in the previous stage buffer tank exceeds the set height, the liquid working medium can naturally overflow to the next stage by gravity, automatically maintaining the dynamic balance of liquid levels at each stage without the need for complex control mechanisms. This simplifies the structure and enhances the system's adaptive capacity under varying operating conditions.

[0019] Furthermore, by installing a support mechanism consisting of connecting rings, reinforcing rings, length rods, and reinforcing rods on the outside of the heat pipe body, the heat pipe is reinforced as a whole in both longitudinal and transverse dimensions. Its advantages are: ultra-long gravity heat pipes need to withstand enormous ground pressure and their own weight at depths of thousands of meters. The support mechanism significantly improves the compressive strength and structural integrity of the pipe body, preventing buckling deformation or rupture during long-term service, and providing reliable structural protection for deep-penetration engineering applications. Attached Figure Description

[0020] Figure 1 This is a perspective view of the improved multi-stage ultra-long gravity heat pipe of the present invention; Figure 2 This is a cross-sectional view of the improved multi-stage ultra-long gravity heat pipe of the present invention; Figure 3 This is an enlarged schematic diagram of point A of the improved multi-stage ultra-long gravity heat pipe of the present invention; Figure 4 This is a connection diagram of the return pipe and the two-phase flow mechanism of the present invention; The components are: 1. Heat pipe body; 2. Support mechanism; 21. Reinforcing rod; 22. Reinforcing ring; 23. Connecting ring; 24. Length rod; 3. Steam pool; 4. Two-phase flow mechanism; 41. Buffer pool; 42. Overflow pipe; 43. Open liquid tank; 44. Dividing pipe; 45. Liquid level valve; 5. Return pipe. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] This invention discloses an improved multi-stage ultra-long gravity heat pipe, comprising a heat pipe body 1, a support mechanism 2 fixedly installed on the outer side of the heat pipe body 1, a plurality of steam pools 3 fixedly installed on one side of the inner wall of the heat pipe body 1, a plurality of two-phase flow mechanisms 4 fixedly installed on the other side of the inner wall of the heat pipe body 1, and a return pipe 5 extending into the two-phase flow mechanism 4 fixedly installed inside the heat pipe body 1; each of the plurality of two-phase flow mechanisms 4 includes a buffer pool 41 and an overflow pipe 42, one side of the bottom end of the buffer pool 41 is fixedly connected to the top end of the overflow pipe 42, the bottom end of the buffer pool 41 is provided with a plurality of open liquid tanks 43, and the other side of the bottom end of the buffer pool 41 is fixedly connected to a distribution pipe 44 extending into the plurality of open liquid tanks 43. By arranging multiple steam pools 3 and multiple two-phase flow mechanisms 4 alternately along the axial direction inside the heat pipe body 1, and cooperating with the return liquid pipe 5 to form a multi-stage segmented circulation path, its core advantage lies in breaking down the single long-distance liquid column in traditional ultra-long gravity heat pipes into multiple independent short liquid column segments. Each stage of the two-phase flow mechanism 4 independently undertakes the local working fluid distribution and phase change circulation. This multi-stage configuration fundamentally avoids the large accumulation of liquid working fluid at the bottom at depths of thousands of meters, significantly reduces the static pressure load of the evaporation section, thereby eliminating the inhibitory effect of high static pressure on the boiling phase change of the working fluid, and ensuring that the heat pipe can maintain stable heat transfer performance under deep burial conditions.

[0024] Preferably, a plurality of level valves 45 extending into the interior of the open liquid tank 43 are fixedly installed on the surface of the distribution pipe 44. By installing level valves 45 extending into the interior of each open liquid tank 43 on the surface of the distribution pipe 44, real-time sensing and active adjustment of the liquid level in each open liquid tank 43 are achieved. Its advantages are: it can dynamically distribute the working fluid flow rate according to the differences in evaporation intensity at each stage, avoiding localized excessively high liquid levels leading to static pressure accumulation or excessively low liquid levels causing drying failure, ensuring that each stage in the multi-stage configuration operates within the optimal liquid level range, thereby improving the uniformity of heat transfer and operational stability of the entire pipe.

[0025] Preferably, the bottom end of the overflow pipe 42 is fixedly connected to the interior of the buffer tank 41. This fixed connection establishes a clear interstage overflow path. Its advantage lies in the fact that when the liquid level in the previous stage buffer tank 41 exceeds a set height, the liquid working fluid can naturally overflow to the next stage by gravity, automatically maintaining the dynamic balance of liquid levels at each stage without any external control mechanism. This simplifies the system structure and enhances the heat pipe's adaptability under varying operating conditions.

[0026] Preferably, the bottom end of the return pipe 5 is fixedly connected to the buffer solution tank 41 directly opposite. This fixed connection establishes a direct reflux channel from the condensation section to each level of the buffer solution tank 41. Its advantage is that the condensed liquid working fluid can be directly transported to each level of the buffer solution tank 41 without intermediate steps, avoiding uneven flow distribution caused by flash evaporation or pressure fluctuations along the way during long-distance reflux, thus improving the certainty and response speed of the working fluid reflux.

[0027] Preferably, one end of each of the buffer pools 41 and one end of each of the open liquid tanks 43 are fixedly connected to the heat pipe body 1. This fixed connection ensures that the two-phase flow mechanism 4 forms a stable, rigid connection within the heat pipe body 1. Its advantage lies in the fact that during the lowering, hoisting, and long-term service of ultra-long gravity heat pipes (several kilometers long), the fixed connection can withstand enormous self-weight loads and vibration impacts, preventing relative displacement or detachment of internal components and ensuring the structural integrity and long-term reliability of the multi-stage configuration under extreme conditions.

[0028] Preferably, the support mechanism 2 includes several connecting rings 23 and several reinforcing rings 22. Several length rods 24 are fixedly installed on the outer side of each of the connecting rings 23. One end of each length rod 24 is fixedly connected to the inner side of each of the reinforcing rings 22. Several reinforcing rods 21 are fixedly installed between every two adjacent reinforcing rings 22. By setting the support mechanism 2, composed of connecting rings 23, reinforcing rings 22, length rods 24, and reinforcing rods 21, on the outer side of the heat pipe body 1, the heat pipe is reinforced as a whole in both longitudinal and transverse dimensions. The length rods 24 provide tensile and compressive strength in the longitudinal direction, while the reinforcing rods 21 and reinforcing rings 22 provide buckling resistance in the transverse direction. Its advantage is that ultra-long gravity heat pipes need to withstand ground pressure, self-weight, and temperature stress at burial depths of thousands of meters. This support mechanism 2 significantly improves the compressive strength and deformation resistance of the pipe body, preventing buckling, rupture, or instability during long-term service, and providing reliable structural protection for deep engineering applications.

[0029] Preferably, the inner sides of several connecting rings 23 are fixedly connected to the heat pipe body 1. Fixing the inner sides of the connecting rings 23 to the heat pipe body 1 ensures that the support mechanism 2 is firmly attached to the outer side of the heat pipe body 1. This has the advantage of achieving integrated load-bearing between the support mechanism 2 and the heat pipe body 1, preventing relative sliding or separation between them; simultaneously, the connecting rings 23, as a force transmission hub, can evenly transmit the constraint forces applied by the length rod 24, the reinforcing rod 21, and the reinforcing ring 22 to the surface of the heat pipe body 1, avoiding localized stress concentration and further improving the overall structural safety margin.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 , Figure 2 , Figure 3 and Figure 4 This invention provides an improved multi-stage ultra-long gravity heat pipe, comprising a heat pipe body 1; a support mechanism 2 is fixedly installed on the outer side of the heat pipe body 1; a plurality of steam pools 3 are fixedly installed on one side of the inner wall of the heat pipe body 1; a plurality of two-phase flow mechanisms 4 are fixedly installed on the other side of the inner wall of the heat pipe body 1; and a return pipe 5 extending into the two-phase flow mechanism 4 is fixedly installed inside the heat pipe body 1; each of the plurality of two-phase flow mechanisms 4 includes a buffer pool 41 and an overflow pipe 42; one side of the bottom end of the buffer pool 41 is fixedly connected to the top end of the overflow pipe 42; the bottom end of the buffer pool 41 is provided with a plurality of open liquid tanks 43; and the other side of the bottom end of the buffer pool 41 is fixedly connected to a distribution pipe 44 extending into the plurality of open liquid tanks 43.

[0031] During use, the entire device involves two-phase flow and heat transfer through evaporation and condensation.

[0032] Several level valves 45 extending into the open liquid tank 43 are fixedly installed on the surface of the separator 44.

[0033] During use, the level valve 45 senses the liquid level in the open liquid tank 43 in real time.

[0034] The bottom end of the overflow pipe 42 is fixedly connected to the interior of the buffer pool 41.

[0035] In use, buffer pool 41 is connected to buffer pool 41 through overflow pipe 42.

[0036] The bottom end of the return tube 5 is fixedly connected to the buffer pool 41 directly opposite it.

[0037] When in use, the vapor in the buffer solution tank 41 is discharged through the return pipe 5.

[0038] One end of each of the several buffer pools 41 and one end of each of the several open liquid tanks 43 are fixedly connected to the heat pipe body 1.

[0039] In use, the two-phase flow mechanism 4 is installed on the heat pipe body 1 through the buffer pool 41 and the open liquid tank 43.

[0040] The support mechanism 2 includes several connecting rings 23 and several reinforcing rings 22. Several length rods 24 are fixedly installed on the outer side of each of the connecting rings 23. One end of each length rod 24 is fixedly connected to the inner side of each of the reinforcing rings 22. Several reinforcing rods 21 are fixedly installed between each pair of adjacent reinforcing rings 22.

[0041] In use, the length rod 24 is used to reinforce the heat pipe body 1 longitudinally from the outside to improve the compressive strength of the heat pipe body 1. The reinforcing rod 21 and the reinforcing ring 22 are used to reinforce the heat pipe body 1 transversely from the outside to improve the compressive strength of the heat pipe body 1.

[0042] The inner sides of several connecting rings 23 are fixedly connected to the heat pipe body 1.

[0043] In use, the support mechanism 2 is installed on the outside of the heat pipe body 1 via the connecting ring 23.

[0044] In this invention, the length rod 24 is longitudinally reinforced from the outside of the heat pipe body 1 to improve its compressive strength. The reinforcing rod 21 and the reinforcing ring 22 are transversely reinforced from the outside of the heat pipe body 1 to improve its compressive strength. The entire device involves two-phase flow and evaporation-condensation heat transfer. The buffer pools 41 are connected by an overflow pipe 42. The level valve 45 senses the liquid level in the open liquid tank 43 in real time. During evaporation and condensation, heat transfer is mainly due to the latent heat of phase change of the working fluid, which is much higher than the single-phase sensible heat transfer. The heat transfer rate is controlled by the gas-liquid interface structure, such as the liquid film thickness, bubble dynamics, and interfacial transport resistance. Different flow regimes, such as bubbly, annular, misty, and stratified flow, significantly affect the heat transfer coefficient, and the corresponding correlation formula needs to be selected in combination with the flow pattern. The Lee model was used for verification. ; Where coeff is an empirical coefficient that depends on the bubble diameter d. b saturation temperature T sat Latent heat L parameter.

[0045] This invention, through the setting of a two-phase flow mechanism 4, enables the improved multi-stage ultra-long gravity heat pipe to achieve the step-by-step reflux and distribution of the working fluid entirely by gravity without any external power input. Specifically, the liquid working fluid is transported to each level of buffer tank 41 via the return pipe 5, then distributed to each open liquid tank 43 via the distribution pipe 44, and finally overflows naturally to the next level via the overflow pipe 42, forming a purely passive multi-stage segmented circulation. Compared with traditional heat pipe or mechanical pump driven circulation systems, this design has the inherent advantages of extremely low energy consumption and low operation and maintenance costs; at the same time, since the heat transfer process is dominated by the latent heat of phase change of the working fluid, its equivalent heat transfer coefficient is significantly higher than that of traditional metal heat-conducting materials such as copper. More importantly, this multi-stage configuration completely avoids the need for groundwater extraction, eliminating a series of environmental and engineering problems such as geological subsidence, brine scaling, and water resource consumption that may be caused by large-scale water extraction. By breaking down a kilometer-long liquid column into multiple controllable short liquid column segments, the static pressure load at the bottom of the evaporation section is effectively reduced, and the inhibitory effect of high static pressure on the boiling phase change of the working fluid is completely eliminated. This fundamentally avoids the phenomenon of heat transfer performance degradation or even failure of ultra-long heat pipes under deep burial conditions, and provides a reliable technical path for the efficient, clean, and low-cost development of deep geothermal resources.

[0046] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An improved multi-stage ultra-long gravity heat pipe, characterized in that, Including the heat pipe body (1); The interior of the heat pipe body (1) is provided with multiple steam pools (3) and multiple two-phase flow mechanisms (4) arranged axially; the steam pools (3) and the two-phase flow mechanisms (4) are arranged opposite to each other; The two-phase flow mechanism (4) includes a buffer pool (41) and an overflow pipe (42). One side of the bottom of the buffer pool (41) is connected to the overflow pipe (42). The bottom of the buffer pool (41) is provided with a plurality of open liquid tanks (43). The other side of the bottom of the buffer pool (41) is connected to a dispensing pipe (44) extending to the open liquid tanks (43). The heat pipe body (1) is also provided with a return pipe (5), which extends into the two-phase flow mechanism (4).

2. The improved multi-stage ultra-long gravity heat pipe according to claim 1, characterized in that, The liquid distribution pipe (44) is equipped with a plurality of liquid level valves (45) that extend into the corresponding open liquid tank (43).

3. The improved multi-stage ultra-long gravity heat pipe according to claim 1, characterized in that, The bottom end of the overflow pipe (42) is connected to the interior of the adjacent buffer pool (41).

4. The improved multi-stage ultra-long gravity heat pipe according to claim 1, characterized in that, The bottom end of the return pipe (5) is connected to the opposite buffer pool (41).

5. An improved multi-stage ultra-long gravity heat pipe according to claim 1, characterized in that, Both the buffer pool (41) and the open liquid tank (43) are fixedly connected to the inner wall of the heat pipe body (1).

6. An improved multi-stage ultra-long gravity heat pipe according to claim 1, characterized in that, The outer side of the heat pipe body (1) is provided with a support mechanism (2), which includes multiple connecting rings (23) and multiple reinforcing rings (22).

7. An improved multi-stage ultra-long gravity heat pipe according to claim 6, characterized in that, Multiple length rods (24) are installed on the outside of the connecting ring (23). The ends of the length rods (24) are connected to the corresponding reinforcing rings (22). Multiple reinforcing rods (21) are provided between adjacent reinforcing rings (22).

8. An improved multi-stage ultra-long gravity heat pipe according to claim 7, characterized in that, The inner side of the connecting ring (23) is fixedly connected to the heat pipe body (1).

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