A waste heat recovery device for a medium-deep geothermal ground heat pipe heat extraction

Abstract

The utility model discloses a kind of waste heat recovery devices for medium-deep geothermal buried pipe heat extraction, it is related to geothermal energy technical field.The utility model includes shell, the two sides of shell are respectively fixedly connected with first side cover and second side cover, the inside of shell is fixedly connected with multiple heat exchange pipes at equal intervals, the inside of shell is provided with baffling component, baffling component includes two installation cylinders fixedly connected in the inside of shell two sides respectively, the inside of installation cylinder is fixedly connected with electromagnet.The utility model is driven movable rod and baffle to move by electromagnet and iron sheet, reduce flowing dead zone by reciprocating linear motion of baffle, solve the problem that the existing baffle flowing dead zone is larger and is easy to induce vibration, simultaneously by winding shaft to winding rope is wound, so that winding rope drives sponge stick to pass through heat exchange pipe, the inside wall of heat exchange pipe is cleaned by sponge stick, solve the problem that the existing heat exchange pipe is not convenient to clean.

Description

Technical Field

[0001] This utility model belongs to the field of geothermal energy technology, and in particular relates to a waste heat recovery device for heat extraction from medium-deep geothermal buried pipes. Background Technology

[0002] Medium-deep geothermal energy refers to the thermal energy contained in hot rock masses and fluids at a certain depth below the Earth's surface (usually 200 to 3,000 meters, sometimes extending to 5,000 meters). It is an important component of geothermal energy resources and is distinct from shallow geothermal energy and deep dry hot rock. The extraction of medium-deep geothermal energy generally uses buried pipes, also known as "heat extraction without water extraction" technology. Waste heat recovery devices are an important component of medium-deep geothermal extraction systems. The existing authorization announcement document CN222012807U discloses a shell-and-tube heat exchanger, including a shell body, a tube-side medium inlet fixedly connected to the top of the shell body, a shell-side medium inlet fixedly connected to the top of the shell body, a tube-side medium outlet fixedly connected to the bottom of the shell body, a shell-side medium outlet fixedly connected to the bottom of the shell body, a heat exchange structure provided inside the shell body, and a scale collection structure provided at the bottom of the shell body; However, it still has the following drawbacks in practical use: 1. The shell-and-tube heat exchanger mentioned above has a heat exchange structure including tube sheet, heat exchange tubes and baffles. The baffles deflect the fluid in the shell, thereby prolonging the flow time of the fluid in the shell and enhancing the waste heat recovery efficiency. However, during use, the baffles have flow dead zones, large pressure drops, and are prone to inducing vibration, which affects waste heat recovery. 2. The shell-and-tube heat exchanger mentioned above has a heat exchange structure including a tube sheet, heat exchange tubes, and baffles. The heat exchange tubes are installed through the tube sheet and heat exchange is carried out through the heat exchange tubes, thereby realizing the recovery and reuse of waste heat. However, during use, some dirt in the water will adhere to the inner wall of the heat exchange tubes, thus forming scale. The presence of scale will affect the heat exchange efficiency of the heat exchange tubes, and thus affect the waste heat recovery efficiency.

[0003] To address these issues, we provide a waste heat recovery device for medium-deep geothermal buried pipes to solve the aforementioned problems. Utility Model Content

[0004] The purpose of this invention is to provide a waste heat recovery device for medium-deep geothermal buried pipes. It uses an electromagnet and an iron plate to drive a movable rod and a baffle plate. The reciprocating linear motion of the baffle plate reduces the flow dead zone, solving the problem of large flow dead zones in existing baffle plates that easily induce vibration. Simultaneously, a winding shaft winds up a winding rope, which in turn drives a sponge rod through the heat exchange tube. The sponge rod cleans the inner wall of the heat exchange tube, solving the problem of inconvenient cleaning of existing heat exchange tubes.

[0005] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution: This utility model relates to a waste heat recovery device for medium-deep geothermal buried pipe heat extraction, comprising a shell, with a first side cover and a second side cover fixedly connected to both sides of the shell respectively. Multiple heat exchange tubes are fixedly connected at equal intervals inside the shell. A baffle assembly is provided inside the shell, comprising two mounting cylinders fixedly connected to both sides of the shell, each mounting cylinder having an electromagnet fixedly connected inside. A movable rod is movably connected between the two mounting cylinders, with multiple baffle plates fixedly connected at equal intervals on the outer wall of the movable rod. Iron plates are fixedly connected to both ends of the movable rod. A cleaning assembly is provided inside both the first and second side covers, comprising multiple winding shafts rotatably connected inside the first and second side covers and a sponge rod located at one end of the heat exchange tube. A shaping rod is fixedly connected inside the sponge rod, with winding ropes fixedly connected to both ends of the shaping rod. The end of the winding rope away from the shaping rod is wound around the winding shafts.

[0006] A further feature of this invention is that: tube sheets are fixedly connected to both sides of the inner side of the shell, and both ends of the heat exchange tubes penetrate the tube sheets and are fixedly connected to fixing plates, with the fixing plates respectively attached to the mutually distant end faces of the tube sheets.

[0007] A further feature of this invention is that: a first flange is fixedly connected to both ends of the housing, and a second flange is fixedly connected to both the first side cover and the second side cover; the first flange and the second flange are fixedly connected by bolts.

[0008] A further feature of this invention is that a first water inlet pipe extends through one side of the bottom of the housing, and a first water outlet pipe extends through the other side of the bottom of the housing. The top ends of the first water inlet pipe and the first water outlet pipe extend to the lower sides of the interior of the housing, respectively.

[0009] A further feature of this invention is that a second water inlet pipe extends through the top of the first side cover, a second water outlet pipe extends through the bottom of the first side cover, and a partition is fixedly connected to the center of the interior of the first side cover.

[0010] A further feature of this invention is that mounting plates are welded to both the front and rear ends of the mounting cylinder, and a limiting rod is fixedly connected between adjacent mounting plates on the left and right sides, with one end of the baffle plate attached to the outer wall of the limiting rod.

[0011] A further feature of this invention is that both ends of the movable rod extend into the interior of the mounting cylinder and are fixedly connected to a limiting plate, the outer side wall of the limiting plate is attached to the inner side wall of the mounting cylinder, and the iron sheet is fixedly connected to the limiting plate.

[0012] A further feature of this invention is that: a first bevel gear is fixedly connected to the front end of each winding shaft, the first bevel gear being located outside and in front of the first and second side covers; a pad is fixedly connected to the lower front end face of each of the first and second side covers, a drive motor is fixedly connected to the pad via a motor frame; a mounting base is fixedly connected to the upper front end face of each of the first and second side covers, a drive rod is rotatably connected to the mounting base, the end of the drive rod away from the mounting base is fixedly connected to the output shaft of the drive motor, and multiple second bevel gears are fixedly connected at equal intervals on the outer wall of the drive rod, all of the second bevel gears meshing in front of the first bevel gear.

[0013] This utility model has the following beneficial effects: 1. This utility model uses a baffle assembly and an electromagnet that alternately switches on and off twice. The electromagnet attracts the iron plate, which in turn drives the movable rod and the baffle plate to reciprocate linearly. The movement of the baffle plate reduces the dead zone of liquid flow in the shell, reduces pressure drop, avoids vibration of the heat exchange tube, facilitates heat exchange between the liquid inside and outside the heat exchange tube, and facilitates the recovery of waste heat from the medium-deep geothermal buried pipe system.

[0014] 2. This utility model, by setting up a cleaning component, starts the drive motor. The output shaft of the drive motor drives the drive rod to rotate, and the drive rod drives the winding shaft to rotate. At this time, the winding shaft on one side winds up the winding rope, and the winding shaft on the other side unwinds the winding rope. Under the combined action of the winding ropes on both sides, the shaping rod drives the sponge rod to move in the direction of winding the winding rope, so that the sponge rod passes through the heat exchange tube. The movement of the sponge rod cleans the inner wall of the heat exchange tube, avoiding the formation of scale on the inner wall of the heat exchange tube. The presence of scale does not affect the heat exchange efficiency of the heat exchange tube, thus ensuring the heat exchange efficiency of the heat exchange tube and the waste heat recovery efficiency. This facilitates the recovery and reuse of waste heat from medium and deep geothermal buried pipe systems, enhancing environmental protection. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a front sectional view of the present invention.

[0017] Figure 2 This is a structural disassembly diagram of the shell of this utility model.

[0018] Figure 3 This is a schematic diagram of the structure of the baffle assembly of this utility model.

[0019] Figure 4 This is a partial sectional view of the mounting cylinder of this utility model.

[0020] Figure 5 This is a schematic diagram of the structure of the movable rod of this utility model.

[0021] Figure 6 This is a schematic diagram of the cleaning component of this utility model.

[0022] Figure 7 This is a schematic diagram showing the installation of the winding shaft and drive rod of this utility model.

[0023] Figure 8 This is a structural disassembly diagram of the sponge rod of this utility model.

[0024] The attached diagram lists the components represented by each number as follows: 1-Shell, 101-Tube sheet, 102-First inlet pipe, 103-First outlet pipe, 104-First flange, 2-First side cover, 201-Second inlet pipe, 202-Second outlet pipe, 203-Baffle plate, 204-Second flange, 3-Second side cover, 4-Heat exchange tube, 401-Fixing plate, 5-Baffle assembly, 501-Mounting cylinder, 501a-Mounting plate, 501b-Limiting rod, 502- 502a-Limiting plate, 503-Baffle plate, 504-Electromagnet, 505-Iron sheet, 6-Cleaning assembly, 601-Rewinding shaft, 601a-First bevel gear, 602-Sponge rod, 602a-Shaping rod, 603-Rewinding rope, 604-Drive rod, 604a-Padded block, 604b-Motor frame, 604c-Drive motor, 604d-Mounting base, 604e-Second bevel gear. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0026] Example 1 Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5The first embodiment of this utility model is shown, which provides a waste heat recovery device for medium-deep geothermal buried pipe heat extraction. It includes a shell 1, with a first side cover 2 and a second side cover 3 fixedly connected to both sides of the shell 1. Multiple heat exchange pipes 4 are fixedly connected at equal intervals inside the shell 1. A flow baffle assembly 5 is provided inside the shell 1. The flow baffle assembly 5 includes an installation cylinder 501, a movable rod 502, a flow baffle 503, an electromagnet 504, and an iron plate 505. The electromagnet 504 and the iron plate 505 drive the movable rod 502 and the flow baffle 503 to move. The reciprocating linear motion of the flow baffle 503 reduces the flow dead zone, solving the problem that the existing flow dead zone of the flow baffle 503 is large and easily induces vibration.

[0027] Specifically, there are two mounting cylinders 501, which are fixedly connected to the inside of the housing 1 on both sides. The mounting cylinders 501 are bolted to the tube sheet 101 inside the housing 1. The mounting cylinders 501 are used to install structures such as the movable rod 502 and the electromagnet 504. The electromagnet 504 is fixedly connected inside each mounting cylinder 501. The movable rod 502 is movably connected between the two mounting cylinders 501. Multiple baffles 503 are fixedly connected at equal intervals on the outer wall of the movable rod 502. The movable rod 502 is used to adjust the baffles 503. 03 is installed and drives the baffle plate 503 to reciprocate linearly. The baffle plate 503 is a semi-circular plate. By setting the baffle plate 503, the flow direction of the liquid in the shell 1 is changed, thereby prolonging the flow time of the liquid in the shell 1, increasing the heat exchange time between the liquid in the shell 1 and the liquid in the heat exchange tube 4, and improving the waste heat recovery efficiency. Both ends of the movable rod 502 are fixedly connected with iron plates 505. The electromagnet 504, together with the iron plates 505, drives the movable rod 502 to move, thereby causing the movable rod 502 to drive the baffle plate 503 to move.

[0028] Furthermore, tube sheets 101 are fixedly connected to both sides of the interior of the shell 1. The tube sheets 101 are used to install the heat exchange tubes 4 inside the shell 1 and to seal the interior of the shell 1 to prevent liquid from flowing into the shell 1 from the first side cover 2 and the second side cover 3. Both ends of the heat exchange tubes 4 pass through the tube sheets 101 and are fixedly connected to fixing plates 401. The fixing plates 401 are respectively attached to the opposite end faces of the tube sheets 101. The fixing plates 401 are installed on the heat exchange tubes 4 by means of threaded connection. The installation of the heat exchange tubes 4 and the tube sheets 101 is achieved by setting the fixing plates 401. Both ends of the housing 1 are fixedly connected to a first flange 104, and the first side cover 2 and the second side cover 3 are fixedly connected to a second flange 204. The first flange 104 and the second flange 204 are fixedly connected by bolts. The arrangement of the first flange 104 and the second flange 204 realizes the connection between the housing 1 and the first side cover 2 and the second side cover 3. A first water inlet pipe 102 is inserted through one side of the bottom of the housing 1, and a first water outlet pipe 103 is inserted through the other side of the bottom of the housing 1. The top ends of the first water inlet pipe 102 and the first water outlet pipe 103 extend to the lower sides of the inside of the housing 1, respectively. The first water inlet pipe 102 is used to add liquid into the housing 1, and the first water outlet pipe 103 is used to export the liquid from the housing 1. The top of the first side cover 2 is through a second water inlet pipe 201, the bottom of the first side cover 2 is through a second water outlet pipe 202, and a partition 203 is fixedly connected to the center of the inside of the first side cover 2. Mounting plates 501a are welded to the front and rear ends of the mounting cylinder 501. Limiting rods 501b are fixedly connected between adjacent mounting plates 501a on the left and right sides. One end of the baffle plate 503 is attached to the outer wall of the limiting rod 501b. The limiting rod 501b is set to limit the movement of the baffle plate 503. Both ends of the movable rod 502 extend into the interior of the mounting cylinder 501 and are fixedly connected to the limiting plate 502a. The outer side wall of the limiting plate 502a is attached to the inner side wall of the mounting cylinder 501, and the iron sheet 505 is fixedly connected to the limiting plate 502a.

[0029] The operation process of this embodiment is as follows: First, the first water inlet pipe 102 and the first water outlet pipe 103 of the shell 1 are connected to a water tank, and the second water inlet pipe 201 and the second water outlet pipe 202 on the first side cover 2 are connected to a medium-deep geothermal buried pipe system. Wastewater in the buried pipe system flows into the first side cover 2 through the second water inlet pipe 201. The wastewater flows into the second side cover 3 through the upper heat exchange pipe 4 and flows back into the first side cover 2 through the lower heat exchange pipe 4. Finally, it flows back into the buried pipe system through the second water outlet pipe 202. Cold water in the water tank flows into the shell 1 through the first water inlet pipe 102. Under the deflection effect of the baffle plate 503, the cold water in the water tank flows in a deflection direction in the shell 1. Heat is exchanged between the cold water and the heat exchange pipe 4. Finally, the water in the shell 1 flows out through the first water outlet pipe 103, realizing the waste heat recovery of the wastewater in the buried pipe system. Meanwhile, during the heat exchange process, the electromagnet 504 on the left is turned on first. After the electromagnet 504 is energized, it generates a magnetic field, which attracts the iron plate 505 under the action of the magnetic field. This causes the iron plate 505 on the left to drive the movable rod 502 and the baffle plate 503 to move linearly to the left. When the iron plate 505 on the left comes into contact with the electromagnet 504 on the left, the electromagnet 504 on the left is turned off. Then the electromagnet 504 on the right is turned on, which causes the movable rod 502 and the baffle plate 503 to move to the right. By alternating the switching of the electromagnets 504 on both sides, the linear reciprocating motion of the baffle plate 503 is achieved, and the movement of the baffle plate 503 reduces the dead zone of liquid flow in the shell 1.

[0030] Example 2 Please see Figure 1 , Figure 2 , Figure 6 , Figure 7 and Figure 8 As shown, this is the second embodiment of the present invention. This embodiment is based on the previous embodiment, but differs from the previous embodiment in that: a cleaning component 6 for cleaning the heat exchange tube 4 is provided in both the first side cover 2 and the second side cover 3. The cleaning component 6 includes a winding shaft 601, a sponge rod 602 and a winding rope 603. The winding shaft 601 winds up the winding rope 603, thereby causing the winding rope 603 to drive the sponge rod 602 through the heat exchange tube 4. The sponge rod 602 cleans the inner wall of the heat exchange tube 4, thus solving the problem of the existing inconvenience in cleaning the heat exchange tube 4.

[0031] Specifically, multiple take-up shafts 601 are rotatably connected at equal intervals inside the first side cover 2 and the second side cover 3. The take-up shafts 601 are used to wind the take-up rope 603, and the connection between the take-up shafts 601 and the housing 1 is sealed. Multiple sponge rods 602 are located at one end of the heat exchange tube 4. The sponge rods 602 are used to clean the inner wall of the heat exchange tube 4. The outer diameter of the sponge rods 602 is slightly larger than the inner diameter of the heat exchange tube 4. A shaping rod 602a is fixedly connected inside the sponge rods 602. The shaping rod 602a is used to... The sponge rod 602 is shaped to ensure that the outer wall of the sponge rod 602 is always in contact with the inner wall of the heat exchange tube 4. Both ends of the shaping rod 602a are fixedly connected to the winding rope 603. The end of the winding rope 603 away from the shaping rod 602a is wound on the winding shaft 601. The winding rope 603 is used to connect the shaping rod 602a to the winding shaft 601, and the winding of the winding rope 603 drives the shaping rod 602a to move, thereby driving the sponge rod 602 through the heat exchange tube 4, thus cleaning the inner wall of the heat exchange tube 4.

[0032] Furthermore, a first bevel gear 601a is fixedly connected to the front end of each take-up shaft 601. The first bevel gear 601a is located outside and in front of the first side cover 2 and the second side cover 3. The first bevel gear 601a is configured to drive the take-up shaft 601 to rotate. A pad 604a is fixedly connected to the lower front end face of both the first side cover 2 and the second side cover 3. A drive motor 604c is fixedly connected to the pad 604a via a motor frame 604b. A mounting base 604d is fixedly connected to the upper front end face of both the first side cover 2 and the second side cover 3. A drive rod 604 is rotatably connected to the mounting base 604d. The end of the drive rod 604 away from the mounting base 604d is fixedly connected to the output shaft of the drive motor 604c. Multiple second bevel gears 604e are fixedly connected at equal intervals on the outer wall of the drive rod 604. All second bevel gears 604e mesh in front of the first bevel gear 601a.

[0033] The rest of the structure is the same as in Example 1.

[0034] The operation process of this embodiment is as follows: Start the drive motor 604c and make the output shafts of the two drive motors 604c rotate in opposite directions. The output shafts of the drive motors 604c drive the drive rod 604 to rotate synchronously. During the movement, the drive rod 604 drives the second bevel gear 604e to rotate synchronously. Under the action of meshing transmission between the first bevel gear 601a and the second bevel gear 604e, the take-up shaft 601 rotates. At this time, the take-up shaft 601 on one side winds up the take-up rope 603, and the take-up shaft 601 on the other side unwinds the take-up rope 603. Under the combined action of the take-up ropes 603 on both sides, the shaping rod 602a drives the sponge rod 602 to move in the winding direction of the take-up rope 603, so that the sponge rod 602 passes through the heat exchange tube 4. The movement of the sponge rod 602 cleans the inner wall of the heat exchange tube 4 and prevents scale from forming on the inner wall of the heat exchange tube 4.

[0035] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0036] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it.

Claims

1. A waste heat recovery device for medium-deep geothermal buried pipe heat extraction, comprising a shell (1), characterized in that: The shell (1) is fixedly connected to a first side cover (2) and a second side cover (3) on both sides respectively, and multiple heat exchange tubes (4) are fixedly connected at equal intervals inside the shell (1). A baffle assembly (5) is provided inside the shell (1), and the baffle assembly (5) includes two mounting cylinders (501) fixedly connected to both sides inside the shell (1). An electromagnet (504) is fixedly connected inside each mounting cylinder (501), and a movable rod (502) is movably connected between the two mounting cylinders (501). Multiple baffle plates (503) are fixedly connected at equal intervals on the outer wall of the movable rod (502), and the movable rod (502) is movably connected to the inner side of the shell (1). Iron plates (505) are fixedly connected to both ends of the rod (502). A cleaning component (6) is provided in both the first side cover (2) and the second side cover (3). The cleaning component (6) includes multiple winding shafts (601) rotatably connected in the first side cover (2) and the second side cover (3) and a sponge rod (602) located at one end of the heat exchange tube (4). A shaping rod (602a) is fixedly connected inside the sponge rod (602), and winding ropes (603) are fixedly connected to both ends of the shaping rod (602a). The end of the winding rope (603) away from the shaping rod (602a) is wound on the winding shaft (601).

2. The waste heat recovery device for medium-deep geothermal buried pipe heat extraction according to claim 1, characterized in that, Both sides of the inner side of the shell (1) are fixedly connected to the tube sheet (101), and both ends of the heat exchange tube (4) pass through the tube sheet (101) and are fixedly connected to the fixing plate (401). The fixing plate (401) is respectively attached to the end face of the tube sheet (101) that is far away from each other.

3. The waste heat recovery device for medium-deep geothermal buried pipe heat extraction according to claim 1, characterized in that, Both ends of the housing (1) are fixedly connected with a first flange (104), and the first side cover (2) and the second side cover (3) are fixedly connected with a second flange (204). The first flange (104) and the second flange (204) are fixedly connected by bolts.

4. A waste heat recovery device for medium-deep geothermal buried pipe heat extraction according to claim 3, characterized in that, The bottom side of the housing (1) is provided with a first water inlet pipe (102) and the bottom side of the housing (1) is provided with a first water outlet pipe (103). The top ends of the first water inlet pipe (102) and the first water outlet pipe (103) extend to the lower sides of the interior of the housing (1).

5. A waste heat recovery device for medium-deep geothermal buried pipe heat extraction according to claim 3, characterized in that, The top of the first side cover (2) is penetrated by a second water inlet pipe (201), and the bottom of the first side cover (2) is penetrated by a second water outlet pipe (202). A partition (203) is fixedly connected to the center of the inside of the first side cover (2).

6. A waste heat recovery device for medium-deep geothermal buried pipe heat extraction according to claim 1, characterized in that, Mounting plates (501a) are welded to the front and rear ends of the mounting cylinder (501), and a limiting rod (501b) is fixedly connected between adjacent mounting plates (501a) on the left and right sides. One end of the baffle plate (503) is attached to the outer wall of the limiting rod (501b).

7. A waste heat recovery device for medium-deep geothermal buried pipe heat extraction according to claim 1, characterized in that, Both ends of the movable rod (502) extend into the interior of the mounting cylinder (501) and are fixedly connected to the limiting plate (502a). The outer side wall of the limiting plate (502a) is attached to the inner side wall of the mounting cylinder (501), and the iron sheet (505) is fixedly connected to the limiting plate (502a).

8. A waste heat recovery device for medium-deep geothermal buried pipe heat extraction according to claim 1, characterized in that, The front end of each winding shaft (601) is fixedly connected to a first bevel gear (601a), and the first bevel gear (601a) is located in front of the outside of the first side cover (2) and the second side cover (3). A pad (604a) is fixedly connected below the front end face of the first side cover (2) and the second side cover (3). A drive motor (604c) is fixedly connected to the pad (604a) through a motor frame (604b). A mounting base (604d) is fixedly connected above the front end face of the first side cover (2) and the second side cover (3). A drive rod (604) is rotatably connected to the mounting base (604d). The end of the drive rod (604) away from the mounting base (604d) is fixedly connected to the output shaft of the drive motor (604c). A plurality of second bevel gears (604e) are fixedly connected at equal intervals on the outer wall of the drive rod (604). The second bevel gears (604e) mesh in front of the first bevel gear (601a).

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