A high-efficiency heat extraction device for downhole heat exchange in a medium-deep well

Abstract

The application provides a high-efficiency heat extraction device for heat exchange in a middle-deep well, which comprises an inner tube, the inner tube comprises a heat preservation tube, a reinforcing tube, a filter tube and a counterweight tube, the heat preservation tube is sequentially provided with an inner lining layer, a heat preservation layer and a protective layer from inside to outside, the reinforcing tube is sequentially provided with an inner lining layer, a reinforcing layer, a heat preservation layer and a protective layer from inside to outside, and the counterweight tube is sequentially provided with an inner lining layer, a reinforcing layer, a counterweight layer and a protective layer from inside to outside.In the application, the heat preservation layer and the reinforcing layer made of different materials are arranged, so that the heat preservation capacity of the inner tube is increased, the heat loss caused by the contact between hot water and cold water when the hot water moves upward is avoided, meanwhile, the moving ring can move up and down on the outer wall of the intercepting net, so that the water scale and solid on the intercepting net are cleaned, and the problem that the water scale is accumulated on the inner tube and causes the diameter of the inner tube to become smaller is solved.

Description

Technical Field

[0001] This invention relates to the field of geothermal well heat extraction equipment technology, and in particular to a high-efficiency heat extraction device for medium-deep well downhole heat exchange. Background Technology

[0002] Geothermal energy refers to the natural outward flow of heat from the Earth's molten lava, a type of thermal energy resource originating from the Earth's interior. The Earth's interior is a vast heat reservoir; for example, the temperature of lava ejected from volcanoes can reach 1200℃–1300℃, and the temperature of natural hot springs is mostly above 60℃, with some even reaching 100℃–140℃. This heat from the Earth's interior can be converted into energy. When this heat seeps to the surface, it becomes geothermal energy. To extract geothermal energy, inner and outer pipes are typically placed together in a medium-to-deep well, and a coolant (such as cold water) is filled into the area between the inner and outer pipes. Through the contact between the cold water and the inner wall of the outer pipe, heat exchange occurs with the external hot water. The hot water, after heat exchange, then returns to the heat exchange station through the inner pipe, thus utilizing the geothermal energy. However, during the heat exchange process, since the coolant is usually not pure water, some scale will be generated during the heating process. When this scale enters the inner tube with the water flow, it will adhere to the inner wall of the inner tube. Over time, the accumulation will form hard deposits, gradually narrowing the inner diameter of the inner tube, thus affecting the normal flow of water. At the same time, scale will also adhere to the water inlet at the bottom of the inner tube, causing blockage of the water inlet, thereby reducing the flow rate at the water inlet.

[0003] Chinese patent CN116927721A discloses a descaling device and system for geothermal well pipelines. The device uses a rotary drive to provide cutting power to the descaling device, which drives the scraper teeth to rotate and cut the scale on the inner wall of the geothermal well pipeline. This device solves the problem that excessive scale buildup in geothermal pipelines can easily clog the pipeline, reduce transportation efficiency, and even endanger pipeline safety. However, this method of filtering scale from the inner pipe can damage the pipe wall, thereby affecting the insulation performance and lifespan of the inner pipe, and also increasing production costs.

[0004] Chinese patent CN111678266A discloses a non-intrusive geothermal vent heat extraction device, including a heat exchanger tube, a heat focusing orienter integrated into the front end of the heat exchanger tube; a connecting mesh tube fitted inside the heat exchanger tube and the heat absorption head; and a water absorption mesh tube fitted at the rear end of the connecting mesh tube. This device filters the hot water entering the inner tube by adding a connecting mesh tube. However, this method can only intercept large pieces of scale in the hot water, while small pieces of scale will still enter the inner tube and adhere to it, thus affecting the normal use of the inner tube.

[0005] Current high-efficiency geothermal well systems still have the following problems:

[0006] 1. In traditional medium-deep downhole heat exchange projects, the inner pipes of downhole heat exchangers often use a combination of PERT-II pipes and counterweights. This type of pipe has poor insulation performance. When the hot water after heat exchange enters the inner pipe and moves upward, it exchanges heat with the cold water that just entered through the pipe wall, resulting in heat loss and wasting geothermal resources.

[0007] 2. When cold water exchanges heat with geothermal energy to generate a temperature increase, the calcium and magnesium ions in the cold water become supersaturated and crystallize out, thus producing scale. This scale enters the inner pipe and accumulates on the inner wall. The accumulated scale forms large solid objects, which reduces the diameter of the inner pipe and affects the flow of water. Even if the solid objects fall off, they will fall to the bottom of the inner pipe and still affect the water intake of the inner pipe. Summary of the Invention

[0008] In view of the above situation and to overcome the defects of the prior art, the present invention provides a high-efficiency heat extraction device for medium-deep downhole heat exchange, so as to solve the problems mentioned in the background art.

[0009] The technical solution is that the present invention includes an inner tube, which includes an insulation tube, a reinforcing tube, a filter tube, and a counterweight tube. The insulation tube is provided with an inner lining layer, an insulation layer, and a protective layer from the inside to the outside. The reinforcing tube is provided with an inner lining layer, a reinforcing layer, an insulation layer, and a protective layer from the inside to the outside. The counterweight tube is provided with an inner lining layer, a reinforcing layer, a counterweight layer, and a protective layer from the inside to the outside.

[0010] The filter tube includes an outer shell, an inner liner, a connecting mesh, and a bottom plate. The connecting mesh is disposed on the top of the bottom plate, the inner liner is disposed inside the outer shell, the connecting mesh is disposed between the bottom plate and the outer shell, a mesh frame is fixedly connected to the top of the bottom plate, and an intercepting mesh is connected to the outside of the mesh frame.

[0011] The outer ring of the interception net has a movable ring that slides up and down. Fixed scraping blocks and movable scraping blocks are symmetrically arranged at the upper and lower ends of the movable ring. The fixed scraping blocks and movable scraping blocks are staggered. The fixed scraping blocks and movable scraping blocks have an inclined surface on the side away from the interception net. The side of the fixed scraping blocks and movable scraping blocks away from the inclined surface is slidably connected to the outer wall of the interception net. The fixed scraping blocks and movable scraping blocks have multiple compression chambers of different sizes inside. The compression chambers have exhaust holes that extend through to the inclined surface.

[0012] The movable ring has a square cavity inside, and one end of the movable scraper is fixedly connected to a movable plate located inside the square cavity. A spring is connected to the top of the movable plate.

[0013] A support frame is symmetrically fixedly connected to the inner wall of the lining plate. A rotating rod is rotatably connected inside the symmetrical support frame. A driving assembly is rotatably connected to the outer wall of the rotating rod. The driving assembly includes a cross rod. A ring frame is fixedly connected to the cross rod. The bottom of the ring frame is connected to a movable ring.

[0014] Furthermore, the drive assembly also includes a reciprocating lead screw and rotating fan blades fixedly connected to both ends of the reciprocating lead screw, and the cross bar is drivenly connected to the reciprocating lead screw.

[0015] Furthermore, an annular cavity is provided between the outer shell and the inner liner, the movable ring moves axially within the annular cavity, a strip groove is provided on the side wall of the inner liner that extends into the annular cavity, the cross rod extends from the strip groove into the annular cavity, and a strip cover covering the strip groove is fixedly connected to the cross rod.

[0016] Furthermore, the two ends of the connecting net are provided with symmetrical conical rings, the top conical ring is located at the bottom of the annular cavity and is slidably connected to a movable ring inside, and the bottom conical ring is located at the bottom of the net frame.

[0017] Furthermore, the connecting mesh includes intersecting vertical and horizontal bars, and the width of the fixed scraper block is less than the distance between two adjacent vertical bars.

[0018] Furthermore, the insulation pipe is disposed at the top of the reinforcing pipe, and the filter pipe is located between the reinforcing pipe and the counterweight pipe.

[0019] Furthermore, the reinforcing layer is made of high-strength glass fiber, the insulation layer is made of nano-aerogel material, and the counterweight layer is made of flexible metal wire.

[0020] Compared with existing known technologies, the technical solution provided by this invention has the following significant advantages:

[0021] 1. This device is equipped with fixed and movable scrapers on the moving ring. When hot water flows inside the inner lining plate, the moving ring is driven by the drive component to move up and down on the outer wall of the interception net, thereby cleaning off the scale adsorbed on the interception net. It can clean the scale on the surface of the interception net without power, preventing scale from entering the inner pipe and causing the inner pipe diameter to decrease. This reduces the impact of scale on water flow and extends the service life of the pipe.

[0022] 2. This device has a compression chamber and an exhaust port inside the fixed scraper and the movable scraper. When the fixed scraper and the movable scraper move to the inclined conical ring, it will not affect the cleaning efficiency of scale. At the same time, the fixed scraper can push the scale out between the two vertical bars, so that the scale is discharged from the filter tube, avoiding the situation that the scale that has been cleaned off will be re-adsorbed onto the interception screen, thus ensuring the smooth flow of water during pumping.

[0023] 3. This device uses a high-strength glass fiber reinforcement layer and a nano-aerogel insulation layer inside the pipe, which reduces the thermal conductivity inside the pipe to improve the insulation performance of the pipe. This reduces the heat exchange between the hot water after heat exchange and the newly introduced cold water, and reduces the heat loss when the hot water moves. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the main structure of the present invention.

[0025] Figure 2 This is a schematic diagram of the cross-section of the insulation pipe in this invention.

[0026] Figure 3 This is a schematic cross-sectional view of the reinforcing tube in this invention.

[0027] Figure 4 This is a schematic diagram of the cross-section of the counterweight tube in this invention.

[0028] Figure 5 This is a three-dimensional schematic diagram of the filter tube in this invention.

[0029] Figure 6 This is a three-dimensional cross-sectional view of the filter tube in this invention.

[0030] Figure 7 This is a three-dimensional sectional view of the connection structure between the inner lining plate and the support frame in this invention.

[0031] Figure 8 This is a three-dimensional cross-sectional view of the connection structure between the moving ring and the moving scraper block in this invention.

[0032] Figure 9 This is a three-dimensional schematic diagram of the connection structure between the interception net and the moving ring in this invention.

[0033] Figure 10 This is a three-dimensional cross-sectional view of the connection structure between the interception net and the moving ring in this invention.

[0034] Figure 11 This is a three-dimensional schematic diagram of the connection structure between the drive component and the ring frame in this invention.

[0035] Figure 12This is a three-dimensional schematic diagram of the connection structure between the movable scraper and the compression chamber in this invention.

[0036] Figure 13 This is a three-dimensional schematic diagram of the connecting network in this invention.

[0037] Explanation of the labels in the diagram:

[0038] 101. Insulation pipe; 102. Reinforcing pipe; 103. Filter pipe; 104. Counterweight pipe; 105. Inner lining layer; 106. Insulation layer; 107. Protective layer; 108. Reinforcing layer; 109. Counterweight layer; 201. Outer shell; 202. Inner lining plate; 203. Connecting mesh; 204. Base plate; 205. Grid frame; 206. Interception mesh; 207. Moving ring; 208. Fixed scraper block; 209. Moving scraper block; 210. 211. Inclined surface; 212. Compression chamber; 213. Exhaust port; 214. Square cavity; 215. Moving plate; 216. Spring; 217. Support frame; 218. Rotating rod; 219. Drive assembly; 220. Cross rod; 221. Ring frame; 222. Reciprocating lead screw; 222. Rotating fan blade; 223. Ring cavity; 224. Strip groove; 225. Strip cover; 226. Conical ring; 227. Vertical bar; 228. Horizontal bar. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Depend on Figures 1 to 11The system includes an inner pipe, which is located inside an outer pipe (not shown in the diagram). Cold water enters between the inner and outer pipes, exchanges heat with the medium-deep rock strata, and then returns to the surface through the inner pipe. The inner pipe comprises an insulation pipe 101, a reinforcing pipe 102, a filter pipe 103, and a counterweight pipe 104. From bottom to top, these components are arranged in sequence: counterweight pipe 104, filter pipe 103, reinforcing pipe 102, and insulation pipe 101. The counterweight pipe 104 provides weight to maintain the pipe's vertical position. The filter pipe 103 filters scale from the hot water. The reinforcing pipe 102 and insulation pipe 101 provide insulation and transport for the hot water. The insulation pipe 101 is arranged in sequence from the inside out. The pipe 102 is provided with an inner lining layer 105, an insulation layer 106, and a protective layer 107. The reinforcing layer 108 is made of high-strength glass fiber, which can enhance the pressure bearing capacity of the pipe. The insulation layer 106 is made of nano-aerogel material, which can reduce the thermal conductivity inside the pipe, thereby improving the insulation capacity of the pipe. The counterweight layer 109 is made of flexible metal wire, which can increase the weight at the bottom of the pipe and make it flexible. The reinforcing pipe 102 is provided with an inner lining layer 105, a reinforcing layer 108, an insulation layer 106, and a protective layer 107 from the inside to the outside. The counterweight pipe 104 is provided with an inner lining layer 105, a reinforcing layer 108, a counterweight layer 109, and a protective layer 107 from the inside to the outside.

[0041] refer to Figures 5 to 10 The filter tube 103 includes an outer shell 201, an inner liner 202, a connecting mesh 203, and a base plate 204. The base plate 204 supports the mesh frame 205 and the connecting mesh 203. The connecting mesh 203 is located between the outer shell 201 and the base plate 204. Hot water passing through the connecting mesh 203 is blocked by the intercepting mesh 206. The connecting mesh 203 is located on the top of the base plate 204. The inner liner 202 is located inside the outer shell 201. An annular cavity 223 is provided between the inner liner 202 and the outer shell 201. The connecting mesh 203 is located between the base plate 204 and the outer shell 201. The top of the base plate 204 is fixedly connected to the mesh frame 205. The mesh frame 205 is used to place the intercepting mesh 206. The top of the mesh frame 205 is connected to the inner liner 202, and the outer side of the mesh frame 205 is connected to the intercepting mesh 206.

[0042] refer to Figures 9 to 12A movable ring 207 slides up and down on the outer ring surface of the interception net 206. Fixed scrapers 208 and movable scrapers 209 are symmetrically arranged at the upper and lower ends of the movable ring 207. By moving the movable ring 207 up and down on the interception net 206, the scale and solid matter adsorbed on the interception net 206 are cleaned off. The fixed scrapers 208 and movable scrapers 209 are staggered, with the movable scrapers 209 corresponding to the positions of the vertical bars 227. The fixed scraper 208 is located between the two vertical bars 227. An inclined surface 210 is formed on the side of the fixed scraper 208 and movable scraper 209 away from the interception net 206. The side of block 208 and movable scraper 209 away from the inclined plane 210 is slidably connected to the outer wall of the interception net 206. The fixed scraper 208 and movable scraper 209 have multiple compression chambers 211 of different sizes inside. There are multiple compression chambers 211 of different sizes. The compression chambers 211 closer to the tip are smaller. The fixed scraper 208 and movable scraper 209 have the same structure. In the normal position, the movable scraper 209 protrudes from the fixed scraper 208. When the spring 215 is compressed, the movable scraper 209 will be pressed into the square cavity 213 and then its length will be shorter than that of the fixed scraper 208. The compression chamber 211 has an exhaust hole 212 that extends through the inclined plane 210.

[0043] refer to Figure 8 The moving ring 207 has a square cavity 213 inside. When the moving scraper 209 is blocked by the vertical bar 227, it will be pressed into the square cavity 213. The spring 215 located in the square cavity 213 will be compressed, while the fixed scraper 208 is not blocked and continues to move. One end of the moving scraper 209 is fixedly connected to the moving plate 214 located in the square cavity 213. The top of the moving plate 214 is connected to the spring 215.

[0044] refer to Figures 6 to 11 A support frame 216 is symmetrically fixedly connected to the inner wall of the inner lining plate 202. The symmetrical support frame 216 supports the rotating rod 217. The drive assembly 218 is located between the two support frames 216. The rotating rod 217 is rotatably connected inside the symmetrical support frame 216. The drive assembly 218 is rotatably connected to the outer wall of the rotating rod 217. When hot water flows, it will drive the drive assembly 218 to rotate. The reciprocating screw 221 on the drive assembly 218 causes the moving ring 207 to move up and down on the interception net 206. The drive assembly 218 includes a cross rod 219. A ring frame 220 is fixedly connected to the cross rod 219. The ring frame 220 is located in the annular cavity 223. The cross rod 219 extends into the annular cavity 223 through the strip groove 224 and is connected to the ring frame 220. The bottom of the ring frame 220 is connected to the moving ring 207.

[0045] Specifically, refer to Figure 11The drive assembly 218 also includes a reciprocating lead screw 221 and rotating fan blades 222 fixedly connected to both ends of the reciprocating lead screw 221. When the rotating fan blades 222 are driven by the water flow, they will drive the reciprocating lead screw 221 to rotate. The rotating fan blades 222 are equipped with spiral fan blades. The cross rod 219 is connected to the reciprocating lead screw 221 for transmission.

[0046] Specifically, refer to Figure 6 and Figure 10 An annular cavity 223 is provided between the outer shell 201 and the inner liner 202. The annular cavity 223 is used to accommodate the reciprocating movement of the annular frame 220. The moving ring 207 moves axially within the annular cavity 223. A strip groove 224 is provided on the side wall of the inner liner 202, extending into the annular cavity 223. A strip cover 225 is placed on the strip groove 224 to prevent hot water from entering the annular cavity 223, so as not to affect the movement of the annular frame 220. A cross rod 219 extends from the strip groove 224 into the annular cavity 223. A strip cover 225 covering the strip groove 224 is fixedly connected to the cross rod 219.

[0047] Specifically, refer to Figure 7 and Figure 9 The two ends of the connecting mesh 203 are provided with symmetrical conical rings 226. The inclined surfaces of the symmetrical conical rings 226 face each other. The fixed scraper 208 and the movable scraper 209 can push the scale off the inclined surfaces of the conical rings 226. The top conical ring 226 is located at the bottom of the annular cavity 223 and is slidably connected to the movable ring 207 inside. The bottom conical ring 226 is located at the bottom of the mesh frame 205.

[0048] Specifically, refer to Figure 13 The connecting net 203 includes intersecting vertical bars 227 and horizontal bars 228. The horizontal bars 228 are used to connect the vertical bars 227. The position of each vertical bar 227 corresponds to the position of the movable scraper 209, so that the fixed scraper 208 can pass between two adjacent vertical bars 227. The width of the fixed scraper 208 is smaller than the distance between two adjacent vertical bars 227.

[0049] Specifically, refer to Figure 1 The insulation pipe 101 is located at the top of the reinforcing pipe 102, the filter pipe 103 is located between the reinforcing pipe 102 and the counterweight pipe 104, the counterweight pipe 104 at the bottom is used to increase the weight at the bottom of the pipe, the reinforcing pipe 102 has pressure resistance, and the insulation pipe 101 is used to perform the function of heat preservation.

[0050] Specifically, the reinforcing layer 108 is made of high-strength glass fiber to increase the pressure resistance of the pipe, the insulation layer 106 is made of nano-aerogel material to increase the insulation capacity of the pipe, avoid heat exchange between hot and cold water, and reduce heat loss, and the counterweight layer 109 is made of flexible metal wire, which gives the counterweight layer 109 the ability to bend and also the weight.

[0051] The inner pipe of this invention is placed inside the outer pipe for use. Cold water enters between the inner and outer pipes and exchanges heat with the medium-deep rock strata through the pipe wall of the outer pipe. After heat exchange, the cold water enters the inner pipe through the filter pipe 103. Hot water passes through the filter pipe 103, the reinforcing pipe 102, and the insulation pipe 101 in sequence and then returns to the heat exchange station on the ground, thereby utilizing geothermal energy. The insulation pipe 101 is provided with an inner lining layer 105, an insulation layer 106, and a protective layer 107. The inner lining layer 105 is in direct contact with the hot water. The insulation layer 106 is made of nano-aerogel material and has excellent heat insulation capabilities. The outer protective layer 107 protects the outer wall of the pipe. The reinforcing pipe 102 has an added reinforcing layer 108 inside, which can reduce the thermal conductivity and thus effectively improve the insulation performance of the pipe material, avoid contact with newly entered cold water, and thus reduce heat loss. A counterweight layer 109 is added to the counterweight pipe 104 to increase the weight at the bottom of the pipe, so that the entire pipe remains vertical.

[0052] During use, the heat-exchanged hot water enters the inner liner plate 202 after passing through the connecting mesh 203 on the filter pipe 103. The connecting mesh 203 is used to connect the outer shell 201 and the bottom plate 204. The scale solids in the hot water are filtered and intercepted by the intercepting mesh 206, so that the scale solids in the water are blocked on the intercepting mesh 206. The hot water after passing through the intercepting mesh 206 will move upward. When it moves into the inner liner plate 202, the flowing water will impact the rotating fan blade 222, so that the rotating fan blade 222 can rotate with the flow of water. When the hot water continues to move upward, it will drive the second rotating fan blade 222 to rotate as well, which will further enhance the rotation of the drive component 218.

[0053] When the drive assembly 218 rotates, it will drive the reciprocating screw 221 to rotate together. The cross rod 219 is equipped with a slider that cooperates with the reciprocating screw 221. When the reciprocating screw 221 rotates, it drives the cross rod 219 to perform axial reciprocating motion. The cross rod 219 drives the annular frame 220 located in the annular cavity 223 to move. When the cross rod 219 moves along the strip groove 224, the strip cover 225 on each branch of the cross rod 219 will cover the strip groove 224. The length of the strip cover 225 is longer than the strip groove 224. Even when the cross rod 219 moves to one end of the strip groove 224, the other end of the strip cover 225 can still cover the strip groove 224.

[0054] The cross bar 219 drives the movable ring 207 to move via the ring frame 220. The movable ring 207 is located outside the interception net 206. When it moves up and down, it can clean the scale and solids attached to the interception net 206 through the fixed scraper 208 and movable scraper 209 at both ends. Since the movable scraper 209 extends longer than the fixed scraper 208, and the top of the movable scraper 209 is provided with an arc surface, when the movable scraper 209 scrapes away the scale and solids, the scale and solids will move to one side of the fixed scraper 208 through the arc surface. When the fixed scraper 208 and the movable scraper 209 move to contact the conical ring 226, the tip part will move from the inclined surface of the conical ring 226 to the top. A compression chamber 211 is provided on top. Because the conical ring 226 has an angle, one side of the fixed scraper 208 and the movable scraper 209 changes from a vertical state to an outward tilted state. The internal compression chamber 211 is compressed, so that the fixed scraper 208 and the movable scraper 209 can adapt to the inclined surface of the conical ring 226 and move on it. The exhaust hole 212 on one side of the compression chamber 211 is used to squeeze out the liquid inside when the compression chamber 211 is compressed. After the fixed scraper 208 and the movable scraper 209 move from the interception net 206 to the conical ring 226, they will push the scale solids onto the conical ring 226 together. When the movable ring 207 continues to move, the movable scraper 209 will come into contact with the vertical bar 227 on the connecting net 203.

[0055] Each vertical bar 227 corresponds to the position of the movable scraper 209, so that the fixed scraper 208 is located between the two vertical bars 227. When the movable ring 207 continues to move, the movable scraper 209 will press against the vertical bar 227. Due to the obstruction of the vertical bar 227, the other side of the movable scraper 209 is then pressed into the square cavity 213, and the spring 215 in the square cavity 213 is compressed. Since the fixed scraper 208 is located between the two vertical bars 227, its width is smaller than the distance between the two vertical bars 227, and there is no obstruction from the vertical bars 227, it allows the fixed scraper 208 to move between the two vertical bars 227. The fixed scraper 208 can push the scale solids out from between the two vertical bars 227 through its tip, and push the scale solids out of the filter tube 103, so as to avoid the scale solids being scraped off and re-adsorbed on the interception net 206. Then, because the cross bar 219 changes direction on the reciprocating screw 221, the moving ring 207 also changes direction and moves upward. In this way, the scale solids on the surface of the interception net 206 are cleaned repeatedly. The scale solids that are pushed out will fall down and land at the bottom of the inner tube, so as not to affect the normal water flow of the inner tube.

[0056] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A high-efficiency heat extraction device for medium-deep downhole heat exchange, comprising an inner tube, said inner tube including an insulation tube (101), a reinforcing tube (102), a filter tube (103), and a counterweight tube (104), characterized in that, The insulation pipe (101) is provided with an inner lining layer (105), an insulation layer (106) and a protective layer (107) from the inside to the outside. The reinforcing pipe (102) is provided with an inner lining layer (105), a reinforcing layer (108), an insulation layer (106) and a protective layer (107) from the inside to the outside. The counterweight pipe (104) is provided with an inner lining layer (105), a reinforcing layer (108), a counterweight layer (109) and a protective layer (107) from the inside to the outside. The filter tube (103) includes an outer shell (201), an inner liner (202), a connecting mesh (203), and a base plate (204). The connecting mesh (203) is disposed on the top of the base plate (204), the inner liner (202) is disposed inside the outer shell (201), and the connecting mesh (203) is disposed between the base plate (204) and the outer shell (201). A mesh frame (205) is fixedly connected to the top of the base plate (204), and an intercepting mesh (206) is connected to the outside of the mesh frame (205). The outer ring surface of the interception net (206) has a movable ring (207) that slides up and down. Fixed scraper blocks (208) and movable scraper blocks (209) are symmetrically arranged at the upper and lower ends of the movable ring (207). The fixed scraper blocks (208) and movable scraper blocks (209) are arranged alternately. An inclined surface (210) is opened on the side of the fixed scraper blocks (208) and movable scraper blocks (209) away from the interception net (206). The side of the fixed scraper blocks (208) and movable scraper blocks (209) away from the inclined surface (210) is slidably connected to the outer wall of the interception net (206). Multiple compression chambers (211) of different sizes are opened inside the fixed scraper blocks (208) and movable scraper blocks (209). An exhaust hole (212) penetrating to the inclined surface (210) is opened on the compression chamber (211). The movable ring (207) has a square cavity (213) inside. One end of the movable scraper (209) is fixedly connected to a movable plate (214) located in the square cavity (213). A spring (215) is connected to the top of the movable plate (214). A support frame (216) is symmetrically fixedly connected to the inner wall of the inner lining plate (202). A rotating rod (217) is rotatably connected inside the symmetrical support frame (216). A drive assembly (218) is rotatably connected to the outer wall of the rotating rod (217). The drive assembly (218) includes a cross rod (219). A ring frame (220) is fixedly connected to the cross rod (219). The bottom of the ring frame (220) is connected to the moving ring (207).

2. The high-efficiency heat extraction device for medium-deep downhole heat exchange according to claim 1, characterized in that, The drive assembly (218) also includes a reciprocating lead screw (221) and rotating fan blades (222) fixedly connected to both ends of the reciprocating lead screw (221). The cross bar (219) is connected to the reciprocating lead screw (221) in a transmission connection.

3. The high-efficiency heat extraction device for medium-deep downhole heat exchange according to claim 2, characterized in that, An annular cavity (223) is provided between the outer shell (201) and the inner liner (202). The movable ring (207) moves axially within the annular cavity (223). A strip groove (224) is provided on the side wall of the inner liner (202) and extends into the annular cavity (223). A cross rod (219) extends from the strip groove (224) into the annular cavity (223). A strip cover (225) covering the strip groove (224) is fixedly connected to the cross rod (219).

4. A high-efficiency heat extraction device for medium-deep downhole heat exchange according to claim 1, characterized in that, The connecting net (203) has symmetrical conical rings (226) at both ends. The top conical ring (226) is located at the bottom of the annular cavity (223) and is slidably connected to a movable ring (207). The bottom conical ring (226) is located at the bottom of the net frame (205).

5. A high-efficiency heat extraction device for medium-deep downhole heat exchange according to claim 1, characterized in that, The connecting net (203) includes intersecting vertical bars (227) and horizontal bars (228), and the width of the fixing scraper (208) is less than the distance between two adjacent vertical bars (227).

6. A high-efficiency heat extraction device for medium-deep downhole heat exchange according to claim 1, characterized in that, The heat insulation pipe (101) is disposed on top of the reinforcing pipe (102), and the filter pipe (103) is located between the reinforcing pipe (102) and the counterweight pipe (104).

7. A high-efficiency heat extraction device for medium-deep downhole heat exchange according to claim 6, characterized in that, The reinforcing layer (108) is made of high-strength glass fiber, the insulation layer (106) is made of nano-aerogel material, and the counterweight layer (109) is made of flexible metal wire.

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