A downhole heat exchange combined pipe for geothermal well

Abstract

The present application belongs to the technical field of geothermal energy utilization, and particularly relates to a downhole heat exchange combined pipe for geothermal well, comprising: a heat transfer layer, which is arranged on the inner wall of a straight well; a turbulence anti-blocking structure is arranged on the inner bottom of the heat transfer layer; a heat insulation sleeve is axially connected to the top surface of the turbulence anti-blocking structure; a heat flow gap is arranged between the heat insulation sleeve and the heat transfer layer; one end of the cold water pipe is fixedly connected to the top end of the heat flow gap; a segmented communication pipe structure is sleeved in the heat insulation sleeve; the bottom end of the segmented communication pipe structure is fixedly connected to the turbulence anti-blocking structure through a bottom connecting head; a sealing connecting structure is arranged between the bottom connecting head and the turbulence anti-blocking structure; and the top end of the segmented communication pipe structure is fixedly connected to one end of the hot water pipe through a top connecting head. By using these structures, the downhole heat exchange combined pipe for geothermal well is realized, which can effectively reduce the occurrence of blockage, has better adaptability, can adapt to engineering operation deviation, and has good sealing effect.

Description

Technical Field

[0001] This invention belongs to the field of geothermal energy utilization technology, and particularly relates to a downhole heat exchange combination pipe for geothermal wells. Background Technology

[0002] Currently, commonly used medium-deep geothermal wells typically employ double-casing heat exchangers to provide heating energy for buildings. The circulating heat exchange medium flows downwards through the gap between the outer and inner casings, exiting the double casing upwards from the center of the inner casing at the bottom. The circulating heat exchange medium releases heat and cools down via a heat pump evaporator before flowing back into the double-casing heat exchanger. Geothermal wells are generally 500-4000 meters deep. During heat exchange, the temperature of the circulating heat exchange medium within the double casing is generally greater than 30°C. The double-casing heat exchanger exhibits two different heat transfer directions: in the upper part of the well, when the temperature of the circulating heat exchange medium inside the pipe is higher than the temperature of the surrounding rock layer, heat is transferred from the circulating heat exchange medium to the rock layer; in the lower part of the well, when the temperature of the circulating heat exchange medium inside the pipe is lower than the temperature of the surrounding rock layer, heat is transferred from the rock layer to the circulating heat exchange medium. The heat transfer methods are primarily conduction and convection. The inner and outer tubes of the double-layer heat exchanger are straight tubes. During the process of the circulating heat exchange medium flowing from the bottom of the outer tube into the center of the inner tube, it is easily blocked by sediment. Summary of the Invention

[0003] The purpose of this invention is to provide a downhole heat exchange combination pipe for geothermal wells to solve the above-mentioned problems and effectively reduce the occurrence of blockages.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] A downhole heat exchange assembly pipe for a geothermal well includes: a heat transfer layer disposed on the inner wall of a vertical well; a turbulence-prevention structure disposed at the bottom inner side of the heat transfer layer; a heat insulation sleeve axially connected to the top surface of the turbulence-prevention structure; a heat flow gap disposed between the heat insulation sleeve and the heat transfer layer; the top end of the heat flow gap being fixedly connected to one end of a cold water pipe; and a segmented connecting pipe structure sleeved inside the heat insulation sleeve.

[0006] The bottom end of the segmented connecting pipe structure is fixedly connected to the turbulent flow anti-blocking structure through a bottom connector. A sealing connection structure is provided between the bottom connector and the turbulent flow anti-blocking structure. The top end of the segmented connecting pipe structure is fixedly connected to one end of the hot water pipe through a top connector.

[0007] Preferably, the inner sidewall of the heat transfer layer is provided with a flow guiding thread.

[0008] Preferably, the pitch of the lower part of the guide thread is smaller than the pitch of the upper part.

[0009] Preferably, the segmented connecting pipe structure includes several equally spaced insulation cylinders. The insulation cylinder at the bottom end is threadedly connected to and communicates with the bottom connector, and the insulation cylinder at the top end is threadedly connected to and communicates with the top connector. A connecting pipe is provided between adjacent insulation cylinders. The inner side of the insulation cylinder is provided with an internal thread, and the outer side of the connecting pipe is provided with an external thread. The internal thread and the external thread are threadedly connected.

[0010] Preferably, an inner limiting ring is provided in the middle of the inner side of the insulation cylinder.

[0011] Preferably, the outer side of the insulation cylinder has circumferentially spaced protrusions, and the protrusions are slidably connected to the inner side of the insulation sleeve.

[0012] Preferably, the sealing connection structure includes a sealing inner tube, the upper part of which is threaded to the inner side of the bottom connector, the lower part of which is snapped into the inner side of the turbulence anti-blocking structure, a sealing retaining ring fixedly connected to the outer side of the middle part of the sealing inner tube, a first retaining groove provided on the top surface of the sealing retaining ring, the bottom end of the bottom connector snapping into the first retaining groove, a second retaining groove provided on the bottom surface of the sealing retaining ring, and the top end of the turbulence anti-blocking structure snapping into the second retaining groove;

[0013] The sealing ring is fitted with a sealing outer tube, and the sealing outer tube is threaded with fixing screws at equal intervals along the circumference. One end of the fixing screw is rotatably connected to the outer side of the sealing ring.

[0014] Preferably, the turbulence-preventing structure includes an outer cylinder, the bottom surface of which is fixedly connected to the inner bottom surface of the heat transfer layer, the top surface of which is fixedly connected to the bottom end of the heat insulation sleeve, and the outer cylinder is provided with water inlet holes at equal intervals on its outer side;

[0015] The inner side of the outer cylinder is axially connected to a water pumping pipe. The top end of the water pumping pipe passes through the outer cylinder and is engaged with the second slot. The portion of the water pumping pipe located on the inner side of the outer cylinder has several water pumping pipe inlet holes at equal intervals along the circumference.

[0016] An inner turbulence seat is provided between the outer cylinder and the water pumping pipe. Several turbulence generation passages are opened on the inner side of the inner turbulence seat. The turbulence generation passages are curved. One end of the turbulence generation passage is connected to the corresponding water inlet of the outer shell, and the other end of the turbulence generation passage is connected to the corresponding water inlet of the water pumping pipe.

[0017] Preferably, the bottom outer side of the sealing inner tube is provided with locking teeth, and the top inner side of the water pumping pipe is provided with a toothed groove, and the locking teeth match the toothed groove.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] By setting up a turbulent flow anti-clogging structure, the occurrence of deposition and blockage at the bottom of the inner side of the heat transfer layer in this device can be reduced. When the heat flow passes through the turbulent flow anti-clogging structure, rapid turbulence can occur, thereby impacting the sludge, scale, or salt deposits at the bottom and carrying these deposits upward. They are then discharged from the vertical well through the segmented connecting pipe structure, allowing for external filtration and preventing blockage in the vertical well.

[0020] By incorporating a segmented connecting pipe structure, the height of this device can be adjusted to accommodate engineering deviations, allowing the segmented connecting pipe structure to be easily lengthened or shortened as needed. Through the installation of a sealing connection structure, this device achieves a good seal between the bottom connector and the turbulence-preventing structure.

[0021] These structures enable the development of a geothermal well downhole heat exchange assembly that effectively reduces the occurrence of blockages, has better adaptability, can accommodate deviations in engineering operations, and provides a good sealing effect. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a front sectional view of the device;

[0024] Figure 2 This is a schematic diagram of the inner part of the heat insulation sleeve of this device;

[0025] Figure 3 This is a schematic diagram of the structure of the heat insulation cylinder;

[0026] Figure 4 This is a schematic diagram of the connecting pipe structure;

[0027] Figure 5 This is a schematic diagram of the connection between the segmented connecting pipe structure and the turbulence-preventing structure.

[0028] Figure 6 for Figure 5 Enlarged diagram of part A in the middle;

[0029] Figure 7 This is a schematic diagram of the internal structure of the turbulence-prevention structure.

[0030] Attached reference numerals: 1. Vertical well; 2. Heat transfer layer; 3. Insulation sleeve; 4. Segmented connecting pipe structure; 5. Bottom connector; 6. Sealing connection structure; 7. Turbulent flow anti-clogging structure; 8. Top connector; 9. Cold water pipe; 10. Heat exchanger; 11. High-pressure water pump; 12. Hot water pipe; 201. Flow guide thread; 401. Insulation cylinder; 402. Connecting pipe; 403. Outward protrusion; 404. Inner limiting ring; 40 5. Internal thread; 406. External thread; 601. Sealing inner tube; 602. Clamping tooth; 603. Tooth groove; 604. Sealing outer tube; 605. Fixing screw; 606. First clamping groove; 607. Second clamping groove; 608. Sealing retaining ring; 701. Outer cylinder; 702. Inner turbulence seat; 703. Outer shell water inlet; 704. Turbulence generation passage; 705. Pumping pipe; 706. Pumping pipe water inlet. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Reference Figure 1-7 As shown, the present invention provides a downhole heat exchange combination pipe for a geothermal well, comprising: a heat transfer layer 2, which is disposed on the inner wall of a vertical well 1; a turbulence anti-blocking structure 7 is provided at the bottom of the inner side of the heat transfer layer 2; a heat insulation sleeve 3 is axially connected to the top surface of the turbulence anti-blocking structure 7; a heat flow gap is provided between the heat insulation sleeve 3 and the heat transfer layer 2; the top of the heat flow gap is fixedly connected to one end of a cold water pipe 9; and a segmented connecting pipe structure 4 is sleeved inside the heat insulation sleeve 3.

[0034] The bottom end of the segmented connecting pipe structure 4 is fixedly connected to the turbulent flow anti-blocking structure 7 via the bottom connector 5. A sealing connection structure 6 is provided between the bottom connector 5 and the turbulent flow anti-blocking structure 7. The top end of the segmented connecting pipe structure 4 is fixedly connected to one end of the hot water pipe 12 via the top connector 8.

[0035] Specifically, the top end of the segmented connecting pipe structure 4 is fixedly connected to one end of the hot water pipe 12 via the top connector 8, the other end of the hot water pipe 12 is fixedly connected to the input end of the heat exchanger 10, the output end of the heat exchanger 10 is fixedly connected to one end of the cold water pipe 9, the other end of the cold water pipe 9 is fixedly connected to the hot flow gap, and a high-pressure water pump 11 is provided on the cold water pipe 9.

[0036] By setting up the turbulence-preventing structure 7, the occurrence of deposition and blockage at the bottom of the inner side of the heat transfer layer 2 in this device can be reduced. When the heat flow passes through the turbulence-preventing structure 7, rapid turbulence can occur, thereby impacting the sludge, scale or salt deposits at the bottom and carrying these deposits upward. They are then discharged from the vertical well 1 through the segmented connecting pipe structure 4, and can be filtered externally to prevent blockage in the vertical well 1.

[0037] By incorporating the segmented connecting pipe structure 4, the height of the segmented connecting pipe structure 4 located inside the insulation sleeve 3 can be adjusted to accommodate engineering deviations, allowing the segmented connecting pipe structure 4 to be easily lengthened or shortened as needed. By incorporating the sealing connection structure 6, the device can achieve a good sealing effect between the bottom connector 5 and the turbulence anti-clogging structure 7.

[0038] These structures enable the development of a geothermal well downhole heat exchange assembly that effectively reduces the occurrence of blockages, has better adaptability, can accommodate deviations in engineering operations, and provides a good sealing effect.

[0039] To further optimize the design, a flow-guiding thread 201 is provided on the inner sidewall of the heat transfer layer 2. The flow-guiding thread 201 can not only effectively reduce the turbulence of hot water in the heat flow gap inside the heat transfer layer 2 due to the high temperature at the bottom and the low temperature at the top, thus reducing the resistance to hot water flow, but also increase the heat conduction area and the heating speed of hot water by setting the flow-guiding thread 201, making the heating more efficient.

[0040] The design was further optimized so that the pitch of the lower part of the guide thread 201 is smaller than the pitch of the upper part.

[0041] When the high-pressure water pump 11 pumps water into the hot flow gap, the water flow above has a faster velocity and has not yet been heated to a certain temperature. Therefore, the pitch of the guide thread 201 is larger, which is conducive to the downward flow of the cooler water. However, the water flow below has a higher temperature, so it is necessary to reduce its turbulence. This requires the guide thread 201 to have a smaller pitch, which can effectively reduce the upward turbulence of the hot water.

[0042] Further optimization of the scheme: the segmented connecting pipe structure 4 includes several equally spaced insulation cylinders 401. The insulation cylinder 401 at the bottom is threadedly connected to the bottom connector 5 and communicates with it. The insulation cylinder 401 at the top is threadedly connected to the top connector 8 and communicates with it. A connecting pipe 402 is provided between adjacent insulation cylinders 401. The inner side of the insulation cylinder 401 is provided with an internal thread 405, and the outer side of the connecting pipe 402 is provided with an external thread 406. The internal thread 405 and the external thread 406 are threadedly connected.

[0043] The spacing between the insulation cylinder 401 and the connecting pipe 402 can be adjusted by rotating them, thus adapting well to the height required by the project. This structure not only adapts to the project requirements and has high flexibility, but also meets the needs of handling and transportation.

[0044] To further optimize the design, an inner limiting ring 404 is provided in the middle of the inner side of the insulation cylinder 401. The inner limiting ring 404 can prevent the connecting pipe 402 from entering too deeply into the inner side of a certain insulation cylinder 401, which would cause the insulation cylinder 401 to dislodge in other positions.

[0045] To further optimize the design, the outer side of the insulation cylinder 401 is provided with protrusions 403 at equal intervals along the circumference, and the protrusions 403 are slidably connected to the inner side of the insulation sleeve 3. The protrusions 403 can prevent the insulation cylinder 401 from directly contacting the inner side of the insulation sleeve 3, thereby further reducing heat dissipation.

[0046] Further optimizing the scheme, the sealing connection structure 6 includes a sealing inner tube 601. The upper part of the sealing inner tube 601 is threaded to the inner side of the bottom connector 5. The lower part of the sealing inner tube 601 is snapped into the inner side of the turbulence anti-blocking structure 7. A sealing retaining ring 608 is fixedly connected to the outer side of the middle part of the sealing inner tube 601. The top surface of the sealing retaining ring 608 is provided with a first retaining groove 606. The bottom end of the bottom connector 5 is snapped into the first retaining groove 606. The bottom surface of the sealing retaining ring 608 is provided with a second retaining groove 607. The top end of the turbulence anti-blocking structure 7 is snapped into the second retaining groove 607.

[0047] A sealing outer tube 604 is sleeved on the outside of the sealing ring 608. The sealing outer tube 604 is threaded with fixing screws 605 at equal intervals along the circumference. One end of the fixing screw 605 is rotatably connected to the outside of the sealing ring 608.

[0048] During sealing, simply tightening the fixing screw 605 will seal and lock the bottom end of the bottom connector 5 and the top end of the pumping pipe 705 of the turbulent anti-clogging structure 7. Effective sealing can be achieved through the cooperation of the sealing outer pipe 604 and the sealing inner pipe 601.

[0049] Further optimization of the scheme: the turbulence anti-blocking structure 7 includes an outer cylinder 701, the bottom surface of the outer cylinder 701 is fixedly connected to the inner bottom surface of the heat transfer layer 2, the top surface of the outer cylinder 701 is fixedly connected to the bottom end of the heat insulation sleeve 3, and the outer cylinder 701 is provided with shell water inlet holes 703 at equal intervals on the outer side.

[0050] A water pumping pipe 705 is axially connected to the inner side of the outer cylinder 701. The top end of the water pumping pipe 705 passes through the outer cylinder 701 and is engaged with the second slot 607. The portion of the water pumping pipe 705 located inside the outer cylinder 701 has several water pumping pipe inlet holes 706 at equal intervals along the circumference.

[0051] An inner turbulence seat 702 is provided between the outer cylinder 701 and the water pumping pipe 705. Several turbulence generation passages 704 are opened on the inner side of the inner turbulence seat 702. The turbulence generation passages 704 are curved. One end of the turbulence generation passage 704 is connected to the corresponding outer shell water inlet 703, and the other end of the turbulence generation passage 704 is connected to the corresponding water pumping pipe water inlet 706.

[0052] When hot water enters the curved turbulence generation passage 704, continuous turbulence will occur. The turbulence can flush away the sediments accumulated and adhered inside the turbulence generation passage 704 and the water pumping pipe 705. The flushed-off dirt is then moved out of the pipe by the hot water, thus achieving a good anti-clogging effect.

[0053] The design is further optimized by providing a locking tooth 602 on the outer bottom of the sealing inner tube 601 and a toothed groove 603 on the inner top of the water pumping pipe 705, with the locking tooth 602 matching the toothed groove 603.

[0054] The structural design of the tooth 602 and the tooth groove 603 provides a good connection effect.

[0055] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0056] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A downhole heat exchange assembly pipe for a geothermal well, characterized in that, include: A heat transfer layer (2) is provided on the inner wall of the vertical well (1). A turbulent flow anti-blocking structure (7) is provided at the bottom of the inner side of the heat transfer layer (2). A heat insulation sleeve (3) is axially connected to the top surface of the turbulent flow anti-blocking structure (7). A heat flow gap is provided between the heat insulation sleeve (3) and the heat transfer layer (2). The top of the heat flow gap is fixedly connected to one end of the cold water pipe (9). A segmented connecting pipe structure (4) is sleeved on the inner side of the heat insulation sleeve (3). The bottom end of the segmented connecting pipe structure (4) is fixedly connected to the turbulent anti-blocking structure (7) through the bottom connector (5), and a sealing connection structure (6) is provided between the bottom connector (5) and the turbulent anti-blocking structure (7). The top end of the segmented connecting pipe structure (4) is fixedly connected to one end of the hot water pipe (12) through the top connector (8). The sealing connection structure (6) includes a sealing inner tube (601), the upper part of which is threaded to the inner side of the bottom connector (5), the lower part of which is snapped into the inner side of the turbulent anti-blocking structure (7), and a sealing ring (608) fixedly connected to the outer side of the middle part of the sealing inner tube (601). The top surface of the sealing ring (608) is provided with a first groove (606), the bottom end of the bottom connector (5) is snapped into the first groove (606), the bottom surface of the sealing ring (608) is provided with a second groove (607), and the top end of the turbulent anti-blocking structure (7) is snapped into the second groove (607). The sealing ring (608) is fitted with a sealing outer tube (604) on the outside. The sealing outer tube (604) is threaded with fixing screws (605) at equal intervals along the circumference. One end of the fixing screw (605) is rotatably connected to the outside of the sealing ring (608). The turbulence-preventing structure (7) includes an outer cylinder (701), the bottom surface of the outer cylinder (701) is fixedly connected to the inner bottom surface of the heat transfer layer (2), the top surface of the outer cylinder (701) is fixedly connected to the bottom end of the heat insulation sleeve (3), and the outer cylinder (701) is provided with water inlet holes (703) at equal intervals on the outer side. The outer cylinder (701) is axially connected to a water pump pipe (705). The top end of the water pump pipe (705) passes through the outer cylinder (701) and is engaged with the second slot (607). The portion of the water pump pipe (705) located inside the outer cylinder (701) has several water pump inlet holes (706) evenly spaced along the circumference. An inner turbulence seat (702) is provided between the outer cylinder (701) and the water pumping pipe (705). Several turbulence generation passages (704) are opened on the inner side of the inner turbulence seat (702). The turbulence generation passages (704) are curved. One end of the turbulence generation passage (704) is connected to the corresponding water inlet hole (703) of the outer shell, and the other end of the turbulence generation passage (704) is connected to the corresponding water inlet hole (706) of the water pumping pipe.

2. The downhole heat exchange assembly pipe for a geothermal well according to claim 1, characterized in that, The heat transfer layer (2) has a flow guiding thread (201) on its inner sidewall.

3. The downhole heat exchange assembly pipe for a geothermal well according to claim 2, characterized in that, The pitch of the lower part of the guide thread (201) is smaller than the pitch of the upper part.

4. The downhole heat exchange assembly pipe for a geothermal well according to claim 1, characterized in that, The segmented connecting pipe structure (4) includes several equally spaced insulation cylinders (401). The insulation cylinder (401) at the bottom end is threadedly connected to the bottom connector (5) and communicates with it. The insulation cylinder (401) at the top end is threadedly connected to the top connector (8) and communicates with it. A connecting pipe (402) is provided between adjacent insulation cylinders (401). The insulation cylinder (401) has an internal thread (405) on its inner side and an external thread (406) on its outer side. The internal thread (405) and the external thread (406) are threadedly connected.

5. A downhole heat exchange assembly pipe for a geothermal well according to claim 4, characterized in that, An inner limiting ring (404) is provided in the middle of the inner side of the insulation cylinder (401).

6. A downhole heat exchange assembly pipe for a geothermal well according to claim 4, characterized in that, The outer side of the heat insulation cylinder (401) is provided with an outward protrusion (403) at equal intervals along the circumference, and the outward protrusion (403) is slidably connected to the inner side of the heat insulation sleeve (3).

7. A downhole heat exchange assembly pipe for a geothermal well according to claim 1, characterized in that, The sealing inner tube (601) has a retaining tooth (602) on the outer side of its bottom, and the water pumping pipe (705) has a toothed groove (603) on the inner side of its top, and the retaining tooth (602) matches the toothed groove (603).

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