Safety explosion-proof pressure release valve linkage structure of pressure-bearing boiler

Abstract

The utility model relates to the technical field of boilers, in particular to a safety anti-explosion pressure release valve linkage structure of a pressure-bearing boiler, which comprises a boiler body, a valve nozzle port is arranged on the boiler body, a pressure release valve body is arranged on the outer side of the valve nozzle port, the pressure release valve body comprises a pressure release pipe, an exhaust pipe is arranged on the outer wall of the pressure release pipe, and a threaded groove and a movable groove are arranged on the inner wall of the pressure release pipe. A blocking sliding block used for blocking the vent hole is arranged in the movable groove, a limiting vertical rod is arranged at the top of the blocking sliding block, a limiting sliding block is arranged on the outer wall of the limiting vertical rod, the outer wall of the limiting vertical rod is sleeved with an annular extrusion block, a spring is arranged between the limiting sliding block and the annular extrusion block, the outer side of the pressure relief pipe is sleeved with a sleeve, and an annular pressure sensor is arranged in the sleeve. A pressure adjusting piece is arranged on the outer wall of the pressure relief pipe. According to the safe anti-explosion pressure release valve linkage structure of the pressure-bearing boiler, the pressure adjusting piece drives the sleeve to ascend and descend, the compression amount of the spring is changed, the opening pressure threshold value of the pressure release valve can be adjusted, and the pressure release requirements under different working conditions are met.

Description

Technical Field

[0001] This utility model relates to the field of boiler technology, specifically to a safety explosion-proof pressure relief valve linkage structure for pressure-bearing boilers. Background Technology

[0002] A pressure boiler is a type of equipment used in industrial and domestic applications, capable of producing steam or hot water under high temperature and pressure conditions. It is widely used in power, chemical, metallurgical, and construction industries. The working principle of a pressure boiler is to heat water by burning fuel or using electrical energy, causing the water to rapidly heat up within the sealed boiler and produce steam. Inside the boiler, the water pressure increases with the rising temperature, thus forming high-temperature, high-pressure steam. The design of pressure boilers must meet strict safety standards to prevent explosions caused by excessive pressure. Therefore, the boiler must be equipped with a safety pressure relief device to ensure that excessive pressure can be released promptly in abnormal situations, protecting the safety of equipment and operators.

[0003] Patent CN208967144U discloses a safety explosion-proof pressure relief valve device for a steam pressurized boiler, including a boiler body and a pressure relief valve pipe. The lower end of the pressure relief valve pipe can be fitted onto the valve port of the boiler body. A ring is provided on the inner wall of the pressure relief valve pipe, on which a cylindrical pressure-bearing weight is placed. Under natural conditions, the pressure-bearing weight falls onto the ring under the action of gravity and seals the pressure relief hole on the wall of the pressure relief valve pipe. It can automatically relieve pressure when the pressure inside the boiler body reaches or exceeds a certain pressure value, thus preventing the boiler body from exploding. A top cover is provided at the top end of the pressure relief valve pipe, and a magnet is provided on the lower end face of the top cover. The upper end face of the pressure-bearing weight is made of magnetic metal material, so the pressure-bearing weight can be pushed upward and attracted, and cannot fall back on its own. The boiler will always be in a depressurized state, and the gas will be quickly discharged from the pressure relief hole.

[0004] While the aforementioned existing technologies can automatically release pressure when a certain pressure value is reached or exceeded within the boiler body, thus preventing boiler explosions, in practical use, the pressure relief valve relies primarily on the weight of the pressure-bearing object to seal the pressure relief orifice when closed. This mechanism leads to several shortcomings. First, the weight of the pressure-bearing object is fixed, making it difficult to precisely adjust the opening pressure of the pressure relief valve. When an increase in boiler pressure relief is required, the existing design cannot meet this need, limiting the flexibility and adaptability of the equipment. Furthermore, because the pressure-bearing object seals the pressure relief orifice under gravity, its response speed and stability may be limited, especially in rapidly changing pressure environments, potentially failing to release pressure and seal the orifice in a timely and effective manner. To overcome these shortcomings, we propose a safety explosion-proof pressure relief valve linkage structure for pressurized boilers, aiming to improve the efficiency and reliability of the pressure relief valve through an adjustable design. Utility Model Content

[0005] The purpose of this invention is to provide a safety explosion-proof pressure relief valve linkage structure for pressure-bearing boilers to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] The safety explosion-proof pressure relief valve linkage structure of the pressurized boiler is combined with Figure 1 , Figure 2 and Figure 4 As shown, the system includes a boiler body for containing high-temperature, high-pressure steam or hot water and providing heat exchange. The boiler body has a valve port, which serves as a pressure release outlet and is connected to a pressure relief valve body. A pressure relief valve body is located on the outside of the valve port, integrating a pressure relief assembly and controlling pressure release. The pressure relief valve body includes a pressure relief pipe, which serves as a pressure relief channel and is connected to the valve port. An exhaust pipe is located on the outer wall of the pressure relief pipe, guiding the released high-pressure gas to an external pipe. A threaded groove is formed at the bottom of the inner wall of the pressure relief pipe for threaded connection with the valve port, ensuring a sealed connection between the pressure relief pipe and the valve port. A movable groove is formed inside the pressure relief pipe, providing vertical movement space for a sealing slider. The movable groove and the threaded groove are connected through a vent hole, allowing high-pressure gas to enter the movable groove.

[0008] The movable groove is equipped with a sealing slider for sealing the vent. Under normal conditions, the sealing slider seals the vent; in case of overpressure, it moves upward to release pressure. A limiting vertical rod is located at the top of the sealing slider, restricting its displacement range. A limiting slider is located on the outer wall of the limiting vertical rod, near its bottom. This limiting slider works in conjunction with an annular compression block. The annular compression block is fitted onto the outer wall of the limiting vertical rod and can slide up and down. When the distance between the annular compression block and the limiting slider decreases, the spring is compressed shorter, making it more difficult for the sealing slider to move upward. The system achieves the effect of increasing the pressure relief pressure and conversely decreasing the pressure relief pressure. A spring is provided between the limiting slider and the annular extrusion block. The spring adjusts the opening pressure threshold of the pressure relief valve by the degree of compression. A sleeve is sleeved on the outside of the pressure relief pipe. The sleeve is linked to the pressure regulating component to adjust the pressure relief pressure. An annular pressure sensor is provided at the top of the inner wall of the sleeve. It is connected to the pressure detector through a wire to obtain the pressure value on the top of the sealing slider. The annular pressure sensor detects pressure changes in real time and feeds them back to the pressure detector. The pressure detector can display the pressure value so that the operator can adjust it to the required pressure relief pressure.

[0009] The outer wall of the pressure relief pipe is provided with a pressure regulating component for adjusting the height of the sleeve. The pressure regulating component adjusts the height of the sleeve through mechanical transmission to change the pressure relief pressure.

[0010] Preferred, such as Figure 4As shown, a first rubber ring is provided at the bottom of the inner wall of the movable groove. The first rubber ring enhances the sealing performance between the sealing slider and the bottom of the movable groove. A second rubber ring is provided on the inner wall of the movable groove near the bottom. The second rubber ring further prevents gas leakage. The air inlet end of the exhaust pipe is located between the first rubber ring and the second rubber ring.

[0011] The outer wall of the sealing slider is in contact with the inner wall of the first rubber ring, and the outer wall of the sealing slider is also in contact with the inner wall of the second rubber ring, thereby improving the sealing performance.

[0012] Preferred, combined Figure 2 and Figure 5 As shown, the outer diameter of the limiting slider is larger than the outer diameter of the blocking slider, and the outer wall of the limiting slider fits against the inner wall of the movable groove. The outer diameter design of the limiting slider ensures that it fits against the inner wall of the movable groove to limit displacement.

[0013] The two ends of the spring abut against the opposite sides of the limiting slider and the annular extrusion block, respectively. The abutment design of the two ends of the spring realizes the linear transmission of force. The annular extrusion block abuts against the detection surface of the annular pressure sensor, and the annular extrusion block transmits the pressure change to the annular pressure sensor.

[0014] Preferred, such as Figure 6 As shown, the top of the sleeve has a clearance hole a in the middle for the limiting vertical rod to pass through. The clearance hole a allows the limiting vertical rod to pass through and restricts lateral displacement. The top of the outer wall of the sleeve is provided with a connecting rod, which is connected to a pressure regulating component to transmit the adjustment action. The top of the connecting rod has a clearance hole b, which allows the rotating rod to pass through to achieve height adjustment.

[0015] Preferred, combined Figure 2 and Figure 7 As shown, the pressure regulating component includes a fixed base plate, one end of which is fixedly connected to the bottom of the outer wall of the pressure relief pipe. The top of the fixed base plate is provided with an internally threaded vertical pipe, which achieves linear displacement conversion through a threaded connection. A rotating rod is movably connected inside the internally threaded vertical pipe, and the rotating rod transmits rotational motion to the threaded rod. The bottom end of the rotating rod is provided with a threaded rod that is threadedly connected to the internally threaded vertical pipe. The threaded rod moves up and down inside the internally threaded vertical pipe by rotation. The top end of the rotating rod passes through the clearance hole b and is fixedly connected with a knob. The knob is operated manually to drive pressure adjustment. The bottom of the knob abuts against the top of the connecting rod, thereby positioning the sleeve.

[0016] In use, the threaded rod is passed through the clearance hole b and threaded into the internal threaded vertical tube. Rotating the rotating rod drives the threaded rod to rotate, causing the threaded rod to move downward in the internal threaded vertical tube, thereby driving the sleeve to move downward, which can increase the pressure relief.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] 1. The safety explosion-proof pressure relief valve linkage structure of this pressure-bearing boiler drives the sleeve to rise and fall through the pressure regulating component, thereby changing the compression of the spring and adjusting the opening pressure threshold of the pressure relief valve to meet the pressure relief requirements under different working conditions. This solves the defect that traditional fixed-weight pressure-bearing objects cannot adjust the pressure.

[0019] 2. The safety explosion-proof pressure relief valve linkage structure of this pressure-bearing boiler, with the linkage design of spring and annular compression block combined with real-time feedback from an annular pressure sensor, makes it easy for operators to adjust the pressure relief pressure through pressure regulating components.

[0020] 3. The safety explosion-proof pressure relief valve linkage structure of this pressure-bearing boiler has a first rubber ring and a second rubber ring that fits into the sealing slider. During the up-and-down movement of the sealing slider, it maintains airtightness, effectively avoids high-pressure gas leakage, and ensures the sealing reliability of the pressure relief valve when it is closed.

[0021] 4. The safety explosion-proof pressure relief valve linkage structure of this pressure-bearing boiler uses a mechanical adjustment method that drives a threaded rod with a knob. This retains the intuitiveness of manual adjustment and allows for rapid pressure relief through manual intervention in emergencies, while also simplifying the daily maintenance process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the overall cross-sectional structure of this utility model;

[0024] Figure 3 This is a partial structural schematic diagram of the present invention;

[0025] Figure 4 This is a cross-sectional structural diagram of the pressure relief pipe in this utility model;

[0026] Figure 5 This is a partial structural diagram of the pressure relief valve body in this utility model;

[0027] Figure 6 This is a schematic diagram of the sleeve structure in this utility model;

[0028] Figure 7 This is a partial structural schematic diagram of the pressure regulating component in this utility model;

[0029] In the diagram: 1. Boiler body; 10. Valve port; 2. Pressure relief valve body; 20. Pressure relief pipe; 200. Threaded groove; 201. Movable groove; 202. Vent hole; 21. Exhaust pipe; 22. First rubber ring; 23. Second rubber ring; 24. Sealing slider; 25. Limiting vertical rod; 250. Limiting slider; 26. Spring; 27. Annular extrusion block; 28. Sleeve; 280. Clearance hole a; 281. Connecting rod; 282. Clearance hole b; 29. ​​Annular pressure sensor; 3. Pressure regulating component; 30. Fixed base plate; 31. Internally threaded vertical pipe; 32. Rotating rod; 320. Threaded rod; 33. Knob. Detailed Implementation

[0030] 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 of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component 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 utility model.

[0032] Please see Figures 1-7 This utility model provides a technical solution:

[0033] The safety explosion-proof pressure relief valve linkage structure of the pressurized boiler is combined with Figure 1 , Figure 2 and Figure 4As shown, the system includes a boiler body 1, which is used to contain high-temperature and high-pressure steam or hot water and provide heat exchange. The boiler body 1 is provided with a valve port 10, which serves as a pressure release outlet and is connected to a pressure relief valve body 2. The pressure relief valve body 2 is located on the outside of the valve port 10, and is used to integrate pressure relief components and control pressure release. The pressure relief valve body 2 includes a pressure relief pipe 20, which serves as a pressure relief channel and is connected to the valve port 10. An exhaust pipe 21 is provided on the outer wall of the pressure relief pipe 20. The exhaust pipe 21 is used to guide the released high-pressure gas to an external pipe. The bottom of the inner wall of the pressure relief pipe 20 is provided with a threaded groove 200 for threaded connection with the valve port 10. The threaded groove 200 ensures a sealed connection between the pressure relief pipe 20 and the valve port 10. The pressure relief pipe 20 is provided with a movable groove 201, which provides space for the blocking slider 24 to move up and down. The movable groove 201 and the threaded groove 200 are connected through a vent hole 202, which allows high-pressure gas to enter the movable groove 201.

[0034] The movable groove 201 is equipped with a sealing slider 24 for sealing the vent 202. Under normal conditions, the sealing slider 24 seals the vent 202. When overpressure occurs, it moves upward to open and release pressure. A limiting vertical rod 25 is provided at the top of the sealing slider 24, restricting its displacement range. A limiting slider 250 is located on the outer wall of the limiting vertical rod 25 near its bottom. The limiting slider 250 works in conjunction with an annular compression block 27. The annular compression block 27 is sleeved on the outer wall of the limiting vertical rod 25, allowing it to slide up and down. When the distance between the annular compression block 27 and the limiting slider 250 decreases, the spring 26 is compressed shorter, which leads to… The more difficult it is for the blocking slider 24 to move upward, the greater the pressure relief; conversely, the greater the upward movement, the less pressure relief. A spring 26 is provided between the limiting slider 250 and the annular compression block 27. The spring 26 adjusts the opening pressure threshold of the pressure relief valve by the degree of compression. A sleeve 28 is sleeved on the outside of the pressure relief pipe 20. The sleeve 28 is linked to the pressure regulating component 3 to adjust the pressure relief. An annular pressure sensor 29 is provided at the top of the inner wall of the sleeve 28. It is connected to the pressure detector through a wire to obtain the pressure value at the top of the blocking slider 24. The annular pressure sensor 29 detects pressure changes in real time and feeds them back to the pressure detector. The pressure detector can display the pressure value so that the operator can adjust it to the required pressure relief.

[0035] The outer wall of the pressure relief pipe 20 is provided with a pressure regulating component 3 for adjusting the height of the sleeve 28. The pressure regulating component 3 adjusts the height of the sleeve 28 through mechanical transmission to change the pressure relief pressure.

[0036] In this embodiment, as Figure 4As shown, a first rubber ring 22 is provided at the bottom of the inner wall of the movable groove 201. The first rubber ring 22 enhances the sealing between the sealing slider 24 and the bottom of the movable groove 201. A second rubber ring 23 is provided on the inner wall of the movable groove 201 near the bottom. The second rubber ring 23 further prevents gas leakage. The air inlet end of the exhaust pipe 21 is located between the first rubber ring 22 and the second rubber ring 23.

[0037] The outer wall of the sealing slider 24 is in contact with the inner wall of the first rubber ring 22, and the outer wall of the sealing slider 24 is also in contact with the inner wall of the second rubber ring 23, thereby improving the sealing performance.

[0038] Specifically, in combination Figure 2 and Figure 5 As shown, the outer diameter of the limiting slider 250 is larger than the outer diameter of the blocking slider 24. The outer wall of the limiting slider 250 fits against the inner wall of the movable groove 201. The outer diameter design of the limiting slider 250 ensures that it fits against the inner wall of the movable groove 201 to limit displacement.

[0039] The two ends of the spring 26 abut against the opposite sides of the limiting slider 250 and the annular extrusion block 27, respectively. The abutment design of the two ends of the spring 26 realizes the linear transmission of force. The annular extrusion block 27 abuts against the detection surface of the annular pressure sensor 29, and the annular extrusion block 27 transmits the pressure change to the annular pressure sensor 29.

[0040] Furthermore, such as Figure 6 As shown, a clearance hole a280 is provided in the middle of the top of the sleeve 28 for the limiting vertical rod 25 to pass through. The clearance hole a280 allows the limiting vertical rod 25 to pass through and restricts lateral displacement. A connecting rod 281 is provided at the top of the outer wall of the sleeve 28. The connecting rod 281 is connected to the pressure regulating component 3 to transmit the adjustment action. A clearance hole b282 is provided at the top of the connecting rod 281. The clearance hole b282 allows the rotating rod 32 to pass through to achieve height adjustment.

[0041] Furthermore, in combination Figure 2 and Figure 7 As shown, the pressure regulating component 3 includes a fixed base plate 30. One end of the fixed base plate 30 is fixedly connected to the bottom of the outer wall of the pressure relief pipe 20. The top of the fixed base plate 30 is provided with an internally threaded vertical pipe 31. The internally threaded vertical pipe 31 achieves linear displacement conversion through a threaded connection. A rotating rod 32 is movably connected inside the internally threaded vertical pipe 31. The rotating rod 32 transmits rotational motion to the threaded rod 320. The bottom end of the rotating rod 32 is provided with a threaded rod 320 that is threadedly connected to the internally threaded vertical pipe 31. The threaded rod 320 moves up and down inside the internally threaded vertical pipe 31 by rotation. The top end of the rotating rod 32 passes through the clearance hole b282 and is fixedly connected to a knob 33. The knob 33 is operated manually to drive pressure adjustment. The bottom of the knob 33 abuts against the top of the connecting rod 281, thereby positioning the sleeve 28.

[0042] In use, the threaded rod 320 is passed through the clearance hole b282 and threaded into the internal threaded vertical tube 31. Rotating the rotating rod 32 causes the threaded rod 320 to rotate, causing the threaded rod 320 to move downward in the internal threaded vertical tube 31, thereby causing the sleeve 28 to move downward, which can increase the pressure relief.

[0043] In this embodiment, the safety explosion-proof pressure relief valve linkage structure of the pressure-bearing boiler allows steam or hot water in the boiler body 1 to enter the pressure relief pipe 20 under high pressure through the valve port 10. The pressure relief pipe 20 is sealed to the valve port 10 through the threaded groove 200. When the internal pressure of the boiler exceeds the set threshold, the high-pressure gas enters the movable groove 201 through the vent 202 and pushes the sealing slider 24 upward. The sealing slider 24 drives the limiting vertical rod 25 and the limiting slider 250 to slide upward, and the high-pressure gas is discharged from the exhaust pipe 21. At this time, the spring 26 is compressed, and the annular extrusion block 27 moves along the outer wall of the limiting vertical rod 25 and transmits the pressure to the annular pressure sensor. Device 29, the annular pressure sensor 29 transmits real-time pressure data to an external pressure detector via a wire. Operators can adjust the pressure regulating component 3 based on the pressure detector's display value: rotating the knob 33 drives the rotating rod 32 and threaded rod 320 to move up and down within the internally threaded vertical tube 31. The threaded rod 320, through the connecting rod 281, drives the sleeve 28 to rise and fall, thereby changing the compression of the spring 26 to adjust the pressure relief threshold. When the pressure drops to a safe range, the spring 26 rebounds, pushing the sealing slider 24 downwards. The outer wall of the sealing slider 24 tightly fits against the first rubber ring 22 and the second rubber ring 23 to seal the vent 202, completing the pressure relief process. For emergency pressure relief, the knob 33 can be rotated directly to quickly adjust the position of the sleeve 28 upwards, or the limiting vertical rod 25 can be pulled upwards to quickly move the sealing slider 24 upwards, ensuring the safe operation of the boiler body 1.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A linkage structure of a safety explosion-proof pressure relief valve of a pressure boiler, comprising a boiler body (1), characterized in that: The boiler body (1) is provided with a valve port (10), the outer side of the valve port (10) is provided with a pressure relief valve body (2), the pressure relief valve body (2) comprises a pressure relief pipe (20), the outer wall of the pressure relief pipe (20) is provided with an exhaust pipe (21), the bottom of the inner wall of the pressure relief pipe (20) is provided with a threaded groove (200) for being screwed with the valve port (10), the pressure relief pipe (20) is internally provided with a movable groove (201), the movable groove (201) is communicated with the threaded groove (200) through a vent hole (202), the movable groove (201) is provided with a blocking sliding block (24) for blocking the vent hole (202), the top of the blocking sliding block (24) is provided with a limiting vertical rod (25), the outer wall of the limiting vertical rod (25) and the position close to the bottom are provided with a limiting sliding block (250), the outer wall of the limiting vertical rod (25) is sleeved with an annular extrusion block (27), the limiting sliding block (250) and the annular extrusion block (27) are provided with a spring (26), the outer side of the pressure relief pipe (20) is sleeved with a sleeve pipe (28), the inner wall of the top of the sleeve pipe (28) is provided with an annular pressure sensor (29), the outer wall of the pressure relief pipe (20) is provided with a pressure adjusting part (3) for adjusting the height of the sleeve pipe (28).

2. The safety relief valve linkage for pressure parts of a boiler according to claim 1, characterized in that: The bottom of the inner wall of the movable groove (201) is provided with a first rubber ring (22), the inner wall of the movable groove (201) and the position close to the bottom are provided with a second rubber ring (23), and the air inlet end of the exhaust pipe (21) is located between the first rubber ring (22) and the second rubber ring (23).

3. The safety relief valve linkage for pressure boilers according to claim 2, characterized in that: The outer wall of the blocking sliding block (24) is attached to the inner wall of the first rubber ring (22), and the outer wall of the blocking sliding block (24) is also attached to the inner wall of the second rubber ring (23).

4. The safety relief valve linkage for pressure boilers according to claim 1, characterized in that: The outer diameter of the limiting sliding block (250) is greater than the outer diameter of the blocking sliding block (24), and the outer wall of the limiting sliding block (250) is attached to the inner wall of the movable groove (201).

5. The safety relief valve linkage for pressure boilers according to claim 1, characterized in that: The two ends of the spring (26) are respectively abutted against the opposite sides of the limiting sliding block (250) and the annular extrusion block (27), and the annular extrusion block (27) is abutted against the detection surface of the annular pressure sensor (29).

6. The safety relief valve linkage for pressure boilers according to claim 1, characterized in that: The middle part of the top of the sleeve pipe (28) is provided with an avoiding hole a (280) for the limiting vertical rod (25) to pass through, the top of the outer wall of the sleeve pipe (28) is provided with a connecting rod (281), and the top of the connecting rod (281) is provided with an avoiding hole b (282).

7. The safety relief valve linkage for pressure boilers according to claim 6, characterized in that: The pressure adjusting part (3) comprises a fixed bottom plate (30), one end of the fixed bottom plate (30) is fixedly connected to the bottom of the outer wall of the pressure relief pipe (20), the top of the fixed bottom plate (30) is provided with an internally-threaded vertical pipe (31), the internally-threaded vertical pipe (31) is movably connected with a rotating rod (32), the bottom end of the rotating rod (32) is provided with a threaded rod (320) which is screwed with the internally-threaded vertical pipe (31), and the top end of the rotating rod (32) penetrates through the avoiding hole b (282) and is fixedly connected with a knob (33).

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