A method and device for online monitoring of air tightness of oil-immersed distribution transformer

Abstract

The present invention discloses a method and device for online monitoring of the air tightness of an oil-immersed distribution transformer. A placement plate is provided at the bottom of the discharge plate. One side corresponding to two positioning plates is fixedly connected to the placement plate. Two fixed cylinders are installed on the left and right sides of the two placement plates. Every two adjacent fixed cylinders are symmetrically arranged front and back. Every two adjacent fixed cylinder output ends are commonly fixedly connected to a linkage plate. Two I-beams are fixedly connected to the bottom of the oil-immersed distribution transformer. The present invention can monitor the transformer oil when the transformer oil leaks from the bottom of the oil-immersed distribution transformer through the mutual cooperation between components such as a flip plate, a crank, an L-shaped connecting plate, a placement plate, a motor, an L-shaped fixed rod, a movable block, a screw rod, a swing plate, and a discharge plate. If transformer oil leakage is detected, the bottom of the oil-immersed distribution transformer can be simply repaired to avoid further deterioration of the leakage.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer detection, and in particular to a method and a device for online monitoring of the air tightness of an oil-immersed distribution transformer. Background Art

[0002] Oil-immersed power transformer refers to a transformer whose windings use insulating oil as the insulating medium. The airtightness of an oil-immersed distribution transformer refers to the sealing performance of its casing and internal components to gas, that is, the ability to prevent gas leakage. This is an important indicator of the performance of an oil-immersed distribution transformer and has a significant impact on its stable operation and service life.

[0003] Existing oil-immersed distribution transformers do not have a method for detecting internal air tightness during use. Most of the time, workers inject helium into the transformer and then detect the concentration of helium in the exhaust gas to determine the air tightness. This method has high accuracy, but requires expensive professional equipment and cannot automatically monitor the air tightness of oil-immersed distribution transformers online. Summary of the invention

[0004] To achieve the above object, the present invention provides the following technical solution: a method for online monitoring of the air tightness of an oil-immersed distribution transformer, comprising the following steps: Step 1: Install the monitoring mechanism as a whole at the bottom of the oil-immersed distribution transformer (1) to complete the fixing of the monitoring mechanism as a whole; Step 2: When the oil-immersed distribution transformer (1) starts to leak oil from the bottom, the oil may fall onto the flip mechanism, and the flip mechanism may transfer the oil stains to the surface of the detection mechanism; Step 3: When the detection mechanism is activated, the repair mechanism can be activated. When the repair mechanism is activated, the bottom of the oil-immersed distribution transformer (1) can be repaired.

[0005] A device for online monitoring of the air tightness of an oil-immersed distribution transformer, characterized in that: Preferably, the flipping mechanism in step 2 includes a discharge plate, the discharge plate is fixedly connected with a central axis at the center of the front and rear sides, the two sides corresponding to the central axis are fixedly connected with a gear, a movable plate is hinged at the center of the front side of the gear, and the two gears have a positioning plate on the side away from the discharge plate, a rectangular opening is opened on the positioning plate, the left and right sides of the movable plate are slidingly connected to the inner side wall of the rectangular opening, a return spring is fixedly connected to the bottom of the movable plate, and the bottom end of the return spring is fixedly connected to the bottom of the inner cavity of the rectangular opening, the two positioning plates are fixedly connected with a welding plate on the corresponding side, and the two welding plates are fixedly connected with a rack on the corresponding side.

[0006] Preferably, there is a placement plate at the bottom of the discharge plate, and the corresponding sides of the two positioning plates are fixedly connected to the placement plate. Two fixed cylinders are installed on the left and right sides of the two placement plates, and every two adjacent fixed cylinders are symmetrically arranged front to back. The output ends of every two adjacent fixed cylinders are commonly fixedly connected to a linkage plate, and two I-beams are fixedly connected to the bottom of the oil-immersed distribution transformer, and the two I-beams are symmetrically arranged front to back.

[0007] Preferably, the detection mechanism in step 2 includes a flip plate, and slide grooves are provided on the front and rear sides of the inner cavity of the flip plate, and the inner cavities of the two slide grooves are slidably connected with sliders, and the bottom of the slider is fixedly connected with a spring, and the bottom end of the spring is fixedly connected to the bottom of the inner cavity of the slide groove, and the corresponding sides of the two sliders are commonly fixedly connected with a movable plate, and two openings are provided on the movable plate, and the two openings are symmetrically arranged front and back, and the inner cavity of the openings has a lifting plate.

[0008] Preferably, there are two baffles below the opening, and the two baffles are symmetrically arranged front to back, and the tops of every two adjacent baffles are fitted with the bottoms of adjacent lifting plates, and a trigger is installed at the center of the bottom of the inner cavity of the flip plate, and two push rods are fixedly connected to the bottom of the inner cavity of the flip plate, and the two push rods are symmetrically arranged front to back, and a discharge port is opened at the bottom of the flip plate, and cranks are hinged on the front and back sides of the flip plate, and the other sides of the two cranks are hinged to the placement plate, and two L-shaped connecting plates are fixedly connected to the bottom of the placement plate near the left side, and the two L-shaped connecting plates are symmetrically arranged front to back, and the two L-shaped connecting plates are fitted with the bottom of the flip plate.

[0009] Preferably, the repair mechanism in step 3 includes a rotating plate, the bottom of the rotating plate near the front and rear sides is fixedly connected to a bonding plate, there are two mounting plates on the left side of the rotating plate, the tops of the two mounting plates are fixedly connected to the bottom of the placement plate, the right side of the placement plate is fixedly connected to a hinged plate, the hinged plate is hinged with a swing plate near the center, the other side of the swing plate is hinged to the bonding plate, the swing plate is hinged with an L-shaped swing plate near the bottom, the other side of the L-shaped swing plate is hinged to the bonding plate, and a limiting spring is fixedly connected between the bonding plate and the hinged plate.

[0010] Preferably, magnetic blocks are fixedly connected to the front and rear sides of the rotating plate near the left side, side panels are fixedly connected to the top of the rotating plate near the front and rear sides, the side panel located on the front side has a motor, an L-shaped fixing rod is fixedly connected to the bottom of the motor, the other end of the L-shaped fixing rod is fixedly connected to the rotating plate, the motor power output shaft is fixedly connected to a screw rod, the rear end of the screw rod passes through the inner cavity of the side panel, and two clamping rods are fixedly connected between the two side panels, and the screw rod is located between the two clamping rods.

[0011] Preferably, a movable block is threadedly connected to the outer side of the screw rod near the front end, the inner cavities of the two screw rods both pass through the inner cavity of the movable block, a stirring motor is installed in the inner cavity of the movable block, an arc plate is fixedly connected to the left side of the movable block, a cavity is opened in the inner cavity of the arc plate, a plurality of arc openings are opened on the inner wall of the arc plate, and the plurality of arc openings are linearly arranged from left to right, the power output shaft of the stirring motor passes through the inner cavities of the movable block and the arc plate, and a plurality of brushes are fixedly connected to the outer side of the power output shaft of the stirring motor.

[0012] Preferably, two vertical rods are inserted near the left side of the top of the placement plate, and the two vertical rods are symmetrically arranged front to back. A clamping plate is fixedly sleeved on the outer sides of the two vertical rods near the top, and a fixing spring is sleeved on the outer sides of the vertical rods. The top end of the fixing spring is fixedly connected to the clamping plate, and the bottom end of the fixing spring is fixedly connected to the placement plate.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention can monitor the transformer oil when the bottom of the oil-immersed distribution transformer leaks transformer oil through the mutual cooperation between the flip plate, crank, L-shaped connecting plate, placement plate, motor, L-shaped fixing rod, movable block, screw rod, swing plate, discharge plate and other components. If transformer oil leakage is detected, the bottom of the oil-immersed distribution transformer can be simply repaired to avoid further deterioration of the leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the component placement board structure of the present invention; Figure 3 It is a right view of the structure of the discharge plate of the component of the present invention; Figure 4 This is a schematic diagram of the component placement board structure of the present invention; Figure 5 This is a disassembled diagram of the flip plate structure of the component of the present invention; Figure 6 for Figure 5 Enlarged view of point A in the middle; Figure 7 This is a schematic diagram of the structure of the discharge plate of the component of the present invention; Figure 8 for Figure 7 Enlarged view of point B in the middle; Fig. 9 This is a schematic diagram of the component mounting plate structure of the present invention; Fig.10 This is a schematic diagram of the structure of the rotating plate component of the present invention; Fig.11 for Figure 4 Enlarged view of point C in the middle; Fig.12 This is a schematic diagram of the brush structure of the component of the present invention; Fig.13 for Fig.12 Enlarged view of point D in the middle.

[0015] Numbers in the figure: 1. Oil-immersed distribution transformer; 2. I-beam; 3. Turning plate; 4. Lifting plate; 5. Movable plate; 6. Trigger; 7. Crank; 8. L-shaped connecting plate; 9. Fixed cylinder; 10. Linkage plate; 11. Motor; 12. L-shaped fixed rod; 13. Discharge plate; 14. Placement plate; 15. Side plate; 16. Swivel plate; 17. Movable block; 18. Screw rod; 19. Ejector rod; 20. Baffle; 21 , slider; 22, spring; 23, arc plate; 24, gear; 25, center axis; 26, positioning plate; 27, return spring; 28, moving plate; 29, welding plate; 30, rack; 31, mounting plate; 32, hinged plate; 33, swing plate; 34, limit spring; 35, L-shaped swing plate; 36, fitting plate; 37, clamping rod; 38, splint; 39, fixing spring; 40, vertical rod; 41, brush. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1-13 The present invention provides a technical solution: a method for online monitoring of the air tightness of an oil-immersed distribution transformer, comprising the following steps: Step 1: Install the monitoring mechanism as a whole at the bottom of the oil-immersed distribution transformer 1 to complete the fixing of the monitoring mechanism as a whole; Step 2: When oil starts to leak from the bottom of the oil-immersed distribution transformer 1, the oil may fall onto the flip mechanism, and the flip mechanism may transfer the oil stains to the surface of the detection mechanism; Step 3: When the detection mechanism is activated, the repair mechanism can be activated, and when the repair mechanism is activated, the bottom of the oil-immersed distribution transformer 1 can be repaired.

[0018] A device for online monitoring of the air tightness of an oil-immersed distribution transformer, characterized in that: The flipping mechanism in step 2 includes a discharge plate 13, and a central axis 25 is fixedly connected to the center of the front and rear sides of the discharge plate 13, and a gear 24 is fixedly connected to the corresponding side of the two central axes 25. A movable plate 28 is hinged at the center of the front side of the gear 24, and a positioning plate 26 is provided on the side of the two gears 24 away from the discharge plate 13. A rectangular opening is opened on the positioning plate 26, and the left and right sides of the movable plate 28 are slidably connected to the inner side wall of the rectangular opening. A return spring 27 is fixedly connected to the bottom of the movable plate 28, and the bottom end of the return spring 27 is fixedly connected to the bottom of the inner cavity of the rectangular opening. The corresponding sides of the two positioning plates 26 are fixedly connected to welding plates 29, and the corresponding sides of the two welding plates 29 are fixedly connected to racks 30.

[0019] A placement plate 14 is provided at the bottom of the discharge plate 13, and the corresponding sides of the two positioning plates 26 are fixedly connected to the placement plate 14. Two fixed cylinders 9 are installed on the left and right sides of the two placement plates 14, and every two adjacent fixed cylinders 9 are symmetrically arranged front to back. The output ends of every two adjacent fixed cylinders 9 are commonly fixedly connected to a linkage plate 10, and two I-beams 2 are fixedly connected to the bottom of the oil-immersed distribution transformer 1, and the two I-beams 2 are symmetrically arranged front to back.

[0020] The detection mechanism in step 2 includes a flip plate 3, and slide grooves are provided on the front and rear sides of the inner cavity of the flip plate 3. The inner cavities of the two slide grooves are slidably connected with sliders 21, and the bottom of the slider 21 is fixedly connected with a spring 22. The bottom end of the spring 22 is fixedly connected to the bottom of the inner cavity of the slide groove. The corresponding sides of the two sliders 21 are commonly fixedly connected with a movable plate 5. The movable plate 5 has two openings, and the two openings are symmetrically arranged front and back. The inner cavity of the openings has a lifting plate 4.

[0021] There are two baffles 20 below the opening, and the two baffles 20 are symmetrically arranged front to back, and the tops of every two adjacent baffles 20 are in contact with the bottoms of the adjacent lifting plates 4, and a trigger 6 is installed at the center of the bottom of the inner cavity of the flip plate 3. Two push rods 19 are fixedly connected to the bottom of the inner cavity of the flip plate 3, and the two push rods 19 are symmetrically arranged front to back. A discharge port is provided at the bottom of the flip plate 3, and cranks 7 are hinged on the front and back sides of the flip plate 3. The other sides of the two cranks 7 are hinged on the placement plate 14, and two L-shaped connecting plates 8 are fixedly connected to the bottom of the placement plate 14 near the left side. The two L-shaped connecting plates 8 are symmetrically arranged front to back, and the two L-shaped connecting plates 8 are in contact with the bottom of the flip plate 3.

[0022] The repair mechanism in step 3 includes a rotating plate 16, and the bottom of the rotating plate 16 near the front and rear sides is fixedly connected to a bonding plate 36, there are two mounting plates 31 on the left side of the rotating plate 16, the tops of the two mounting plates 31 are fixedly connected to the bottom of the placement plate 14, and the right side of the placement plate 14 is fixedly connected to a hinged plate 32, the hinged plate 32 is hinged to a swing plate 33 near the center, and the other side of the swing plate 33 is hinged to the bonding plate 36, the swing plate 33 is hinged to an L-shaped swing plate 35 near the bottom, and the other side of the L-shaped swing plate 35 is hinged to the bonding plate 36, and a limiting spring 34 is fixedly connected between the bonding plate 36 and the hinged plate 32.

[0023] Magnetic blocks are fixedly connected to the front and rear sides of the rotating plate 16 near the left side, and side plates 15 are fixedly connected to the top of the rotating plate 16 near the front and rear sides. The side plate 15 located on the front side has a motor 11, and an L-shaped fixing rod 12 is fixedly connected to the bottom of the motor 11. The other end of the L-shaped fixing rod 12 is fixedly connected to the rotating plate 16. The power output shaft of the motor 11 is fixedly connected to a screw rod 18, and the rear end of the screw rod 18 passes through the inner cavity of the side plate 15. Two clamping rods 37 are fixedly connected between the two side plates 15, and the screw rod 18 is located between the two clamping rods 37.

[0024] The outer side of the screw rod 18 is threadedly connected to the movable block 17 near the front end. The inner cavities of the two screw rods 18 pass through the inner cavity of the movable block 17. A stirring motor is installed in the inner cavity of the movable block 17. An arc plate 23 is fixedly connected to the left side of the movable block 17. The inner cavity of the arc plate 23 has a cavity. The inner wall of the arc plate 23 has a plurality of arc openings, which are linearly arranged from left to right. The power output shaft of the stirring motor passes through the inner cavities of the movable block 17 and the arc plate 23. A plurality of brushes 41 are fixedly connected to the outer side of the power output shaft of the stirring motor.

[0025] Two vertical rods 40 are inserted near the left side of the top of the placement plate 14. The two vertical rods 40 are symmetrically arranged front to back. A clamping plate 38 is fixedly sleeved on the outer side of the two vertical rods 40 near the top. A fixing spring 39 is sleeved on the outer side of the vertical rod 40. The top end of the fixing spring 39 is fixedly connected to the clamping plate 38, and the bottom end of the fixing spring 39 is fixedly connected to the placement plate 14.

[0026] Working principle: When there are defects such as sand holes and cracks at the bottom of the oil-immersed distribution transformer 1, the transformer oil inside the oil-immersed distribution transformer 1 will leak downward and accumulate on the surface of the discharge plate 13. When the transformer oil on the top of the discharge plate 13 accumulates to a certain weight, the two gears 24 can be driven to move downward through the central shaft 25. When the gears 24 move downward, the movable plate 28 can be driven to move downward. When the movable plate 28 moves downward, the moving trajectory of the gear 24 can be limited. When the gear 24 moves downward and meshes with the rack 30, it can be turned over, so that the discharge plate 13 can be driven to turn over through the central shaft 25. When the discharge plate 13 turns over, the transformer oil on the surface can be poured to the top of the movable plate 5; Since the transformer oil is poured onto the top of the movable plate 5 through the discharge plate 13 in a centralized manner, the movable plate 5 is driven to move downward. When the movable plate 5 moves downward, the trigger 6 can be activated, and at the same time, the two push rods 19 can lift the corresponding lifting plate 4, so that the transformer oil on the top of the movable plate 5 is discharged to the bottom of the inner cavity of the flip plate 3 and discharged through the discharge port. The discharge plate 13 can be turned 90 degrees by the crank 7, and the clamping plate 38 is fitted with the discharge plate 13, so that the discharge plate 13 is stored; When the staff drives the rotating plate 16 to flip, the flipping trajectory can be limited by the swing plate 33, the L-shaped swing plate 35 and the limit spring 34. When the rotating plate 16 flips to be flush with the placement plate 14, the current position of the rotating plate 16 can be fixed by the magnetic block. When the trigger 6 is activated, the stirring motor can be started. When the stirring motor rotates, it can drive a number of brushes 41 to rotate. When the brushes rotate, they can contact the plugging glue inside the arc-shaped mouth, so as to apply the bottom of the oil-immersed distribution transformer 1. The motor 11 drives the screw rod 18 to rotate, which can drive the movable block 17 to move, so that the bottom of the oil-immersed distribution transformer 1 is coated with a large area.

[0027] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for online monitoring of the air tightness of an oil-immersed distribution transformer, characterized in that: The following steps are involved: Step 1: Install the monitoring mechanism as a whole at the bottom of the oil-immersed distribution transformer (1) to complete the fixing of the monitoring mechanism as a whole; Step 2: When the oil-immersed distribution transformer (1) starts to leak oil from the bottom, the oil may fall onto the flip mechanism, and the flip mechanism may transfer the oil stains to the surface of the detection mechanism; Step 3: When the detection mechanism is activated, the repair mechanism can be activated. When the repair mechanism is activated, the bottom of the oil-immersed distribution transformer (1) can be repaired.

2. A device for online monitoring of the air tightness of an oil-immersed distribution transformer, characterized in that: The turning mechanism in step 2 comprises a discharge plate (13), wherein the discharge plate (13) is fixedly connected with a central shaft (25) at the center of both front and rear sides, and a gear (24) is fixedly connected to the corresponding side of the two central shafts (25), and a movable plate (28) is hingedly connected to the center of the front side of the gear (24), and a positioning plate (26) is provided on the side of the two gears (24) away from the discharge plate (13), and a rectangular opening is opened on the positioning plate (26), and the left and right sides of the movable plate (28) are slidably connected to the inner side wall of the rectangular opening, and a return spring (27) is fixedly connected to the bottom of the movable plate (28), and the bottom end of the return spring (27) is fixedly connected to the bottom of the inner cavity of the rectangular opening, and the corresponding side of the two positioning plates (26) is fixedly connected with a welding plate (29), and the corresponding side of the two welding plates (29) is fixedly connected with a rack (30).

3. The device for online monitoring of air tightness of oil-immersed distribution transformer according to claim 2, characterized in that: A placement plate (14) is provided at the bottom of the discharge plate (13), and corresponding sides of the two positioning plates (26) are fixedly connected to the placement plate (14). Two fixed cylinders (9) are installed on the left and right sides of the two placement plates (14), and each two adjacent fixed cylinders (9) are symmetrically arranged front and back. The output ends of each two adjacent fixed cylinders (9) are commonly fixedly connected to a linkage plate (10). Two I-beams (2) are fixedly connected to the bottom of the oil-immersed distribution transformer (1), and the two I-beams (2) are symmetrically arranged front and back.

4. The device for online monitoring of air tightness of oil-immersed distribution transformer according to claim 3 is characterized in that: The detection mechanism in step 2 comprises a flip plate (3), wherein the flip plate (3) has slide grooves on both the front and rear sides of its inner cavity, wherein the inner cavities of the two slide grooves are slidably connected with sliders (21), wherein the bottom of the slider (21) is fixedly connected with a spring (22), wherein the bottom end of the spring (22) is fixedly connected to the bottom of the inner cavity of the slide groove, wherein the two sliders (21) are fixedly connected with a movable plate (5) on the corresponding sides thereof, wherein the movable plate (5) has two openings, wherein the two openings are symmetrically arranged front and back, and wherein the inner cavities of the openings have a lifting plate (4).

5. The device for online monitoring of air tightness of oil-immersed distribution transformer according to claim 4 is characterized in that: There are two baffles (20) below the opening, the two baffles (20) are symmetrically arranged front to back, and the tops of every two adjacent baffles (20) are in contact with the bottoms of the adjacent lifting plates (4). A trigger (6) is installed at the center of the bottom of the inner cavity of the flip plate (3). Two push rods (19) are fixedly connected to the bottom of the inner cavity of the flip plate (3), and the two push rods (19) are symmetrically arranged front to back. A discharge port is opened at the bottom of the flip plate (3). The flip plate (3) is hinged with cranks (7) on both the front and rear sides, and the other sides of the two cranks (7) are hinged on the placement plate (14). Two L-shaped connecting plates (8) are fixedly connected to the bottom of the placement plate (14) near the left side, and the two L-shaped connecting plates (8) are symmetrically arranged front to back. The two L-shaped connecting plates (8) are in contact with the bottom of the flip plate (3).

6. The device for online monitoring of air tightness of oil-immersed distribution transformer according to claim 5, characterized in that: The repair mechanism in step 3 includes a rotating plate (16), the bottom of the rotating plate (16) is fixedly connected to a bonding plate (36) near the front and rear sides, the left side of the rotating plate (16) has two mounting plates (31), the tops of the two mounting plates (31) are fixedly connected to the bottom of the placement plate (14), the right side of the placement plate (14) is fixedly connected to a hinged plate (32), the hinged plate (32) is hinged to a swing plate (33) near the center, the other side of the swing plate (33) is hinged to the bonding plate (36), the swing plate (33) is hinged to an L-shaped swing plate (35) near the bottom, the other side of the L-shaped swing plate (35) is hinged to the bonding plate (36), and a limit spring (34) is fixedly connected between the bonding plate (36) and the hinged plate (32).

7. The device for online monitoring of air tightness of oil-immersed distribution transformer according to claim 6, characterized in that: The rotating plate (16) is fixedly connected to magnetic blocks at the front and rear sides near the left side, and the top of the rotating plate (16) is fixedly connected to side plates (15) near the front and rear sides. The side plate (15) located at the front side has a motor (11), and the bottom of the motor (11) is fixedly connected to an L-shaped fixing rod (12), and the other end of the L-shaped fixing rod (12) is fixedly connected to the rotating plate (16). The power output shaft of the motor (11) is fixedly connected to a screw rod (18), and the rear end of the screw rod (18) passes through the inner cavity of the side plate (15). Two clamping rods (37) are fixedly connected between the two side plates (15), and the screw rod (18) is located between the two clamping rods (37).

8. The device for online monitoring of air tightness of oil-immersed distribution transformer according to claim 7, characterized in that: The outer side of the screw rod (18) is threadedly connected to a movable block (17) near the front end. The inner cavities of the two screw rods (18) penetrate the inner cavity of the movable block (17). A stirring motor is installed in the inner cavity of the movable block (17). The left side of the movable block (17) is fixedly connected to an arc plate (23). The inner cavity of the arc plate (23) is provided with a cavity. The inner side wall of the arc plate (23) is provided with a plurality of arc openings. The plurality of arc openings are linearly arranged from left to right. The power output shaft of the stirring motor penetrates the inner cavities of the movable block (17) and the arc plate (23). The outer side of the power output shaft of the stirring motor is fixedly connected to a plurality of brushes (41).

9. The device for online monitoring of air tightness of oil-immersed distribution transformer according to claim 6, characterized in that: Two vertical rods (40) are inserted into the top of the placement plate (14) near the left side. The two vertical rods (40) are symmetrically arranged front to back. Clamps (38) are fixedly sleeved on the outer sides of the two vertical rods (40) near the top. A fixing spring (39) is sleeved on the outer sides of the vertical rods (40). The top end of the fixing spring (39) is fixedly connected to the clamps (38), and the bottom end of the fixing spring (39) is fixedly connected to the placement plate (14).

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