Fine filtering equipment

Abstract

The invention relates to fine filtering equipment which comprises a box body, a main motor, a transmission mechanism and a circulating filtering device, the transmission mechanism at least comprises a rotating shaft which is rotatably arranged on the side wall of the box body in a penetrating mode, and the main motor drives the rotating shaft to drive the circulating filtering device which limits target dirt to penetrate through through circulating rotation. The circulating filtering device comprises a belt conveying filtering assembly, the belt conveying filtering assembly comprises a belt-shaped filtering mechanism, a driving belt wheel and a driven belt wheel, the rotating shaft comprises a driving shaft I and a driven shaft, the driving belt wheel penetrates through the driving shaft I, the driven belt wheel penetrates through the driven shaft, and a distance is kept between the driving shaft I and the driven shaft; the strip-shaped filtering mechanism at least comprises a deformable filtering net which is in a continuous strip shape and is tensioned by a driving belt wheel and a driven belt wheel, and a rotating shaft drives the filtering net to move circularly.

Description

Technical Field

[0001] This invention relates to water treatment equipment, and more particularly to fine filtration equipment. Background Technology

[0002] Fine filtration equipment, commonly known as a rotary fine bar screen, is primarily used to separate and remove solids from wastewater. It is mainly used for the re-filtration of return water from MBR membrane tanks, removing solid particles such as membrane fibers that have already been treated in the biological and membrane tanks. The fine filtration equipment uses a rotating, barrel-shaped filter roller that continuously rotates in the water, with part of the roller submerged below the water surface. Water from the membrane tank enters the filter roller through the inlet, and impurities are intercepted, thus achieving filtration. Currently, the rotating shaft and the filter roller driven by the shaft are installed in water channels or stainless steel housings, resulting in a compact and small-sized system. However, with increasingly stringent water quality requirements and ever-increasing wastewater flow rates, water utilities' equipment is often operating at full capacity. This is especially true for the biological and MBR membrane tanks, which are the core of water treatment processes, requiring increased re-filtration flow rates for the membrane tank wastewater. Existing compact fine filtration equipment can no longer meet these demands.

[0003] Increasing the number of fine filtration devices would require extensive water pipeline construction, which would be counterproductive for water companies with numerous underground treatment ponds. Furthermore, the daily processing capacity of each fine filtration device remains fixed. The peak seasons for water treatment are the beginning of each year and summer, while the off-seasons do not have such a large processing capacity, leading to a large number of devices being idle. Therefore, simply increasing the number of devices cannot solve the problem. Summary of the Invention

[0004] To solve the above problems, a fine filtration device is provided. The provided technical solution includes a housing, a main motor, a transmission mechanism, and a circulating filtration device. The transmission mechanism includes at least a rotatable shaft mounted on the side wall of the housing. The main motor drives the shaft to drive the circulating filtration device, which restricts the passage of target dirt through cyclic rotation. The device is characterized by further including a belt conveyor filtration assembly, which includes a belt filter mechanism, a drive pulley, and a driven pulley. The shaft includes a drive shaft I with the drive pulley mounted on it and a driven shaft with the driven pulley mounted on it. A distance is maintained between the drive shaft I and the driven shaft.

[0005] The belt filter mechanism includes at least a deformable filter screen, which is a continuous belt and is tensioned by main and driven pulleys. The rotating shaft drives the filter screen to circulate.

[0006] Based on the above technical solution, a variable adjustment device is also included, which includes a water-blocking component, a motion component, and an adjustment component. The motion component includes a base and a sliding mechanism. The base is fixed on the side wall outside the box, and the sliding mechanism is set on the base.

[0007] The adjustment assembly includes a sliding support and a swing arm. The main body of the sliding support is connected to the sliding mechanism via a support leg. One end of the swing arm can swing on the main body, and the other end of the swing arm is provided with a tension wheel shaft. The tension wheel shaft can rotate coaxially on the connecting arm. The main body is also provided with an auxiliary motor that drives the drive shaft II.

[0008] The water-blocking assembly includes at least a water-blocking plate a and a sealing strip. A working area and a maintenance area are pre-set within the housing. The interval and position between the drive shaft I and the driven shaft are adjusted to match the layout of the working area. The tensioning wheel axle is used to re-tension the untensioned filter screen between the drive shaft I and the driven shaft. The water-blocking plate is detachably inserted vertically into the housing, and the sealing strip detachably seals the gap between the water-blocking plate and the housing, achieving separation of different areas. The water-blocking plate a is hollow inside, and multiple openings are provided on the end face of the water-blocking plate a that contacts the housing. Electromagnets are fixed inside the openings, and the water-blocking plate a is fixed to the housing by electromagnets.

[0009] Based on the above technical solution, the water-blocking assembly includes at least a water-blocking plate b and a sealing strip; the water-blocking plate b is hollow inside, and multiple parallel strip-shaped grooves are opened inside the box. The grooves are opened along the inner wall of the box and the direction of the grooves is perpendicular to the length direction of the box. The water-blocking plate b is inserted from the grooves to divide the box into a preset working area and a maintenance area; the interval and position between the drive shaft I and the driven shaft are adjusted to match the arrangement of the working area; the untensioned filter screen between the drive shaft I and the driven shaft is re-tensioned using the tensioning wheel shaft.

[0010] Based on the above technical solution, the strip filter mechanism also includes a connecting ridge and a fixing insert. The fixing insert is fixed at both ends of the filter screen. The connecting ridge has slots at both ends. The slots have openings extending along the length of the connecting ridge in the direction away from the connecting ridge. The top of the slot is open and serves as an insertion port. The fixing insert is inserted into the slot through the insertion port. The opening is used to accommodate the filter screen.

[0011] Based on the above technical solution, a limiting rod is also fixedly connected to the bottom of the slot. The limiting rod extends to the insertion port along the length of the connecting ridge. A limiting hole that matches the limiting rod is opened at the bottom of the fixing strip. The fixing strip is fitted onto the limiting rod through the limiting hole and fixed.

[0012] The beneficial effects of this invention are as follows:

[0013] (1) The cylindrical filter element was creatively changed to a conveyor circulation scheme, which lengthened and widened the size of the box. The filter screen with the conveyor belt structure can filter more sewage at one time with a larger filtration area, meet the filtration needs during peak water treatment periods, and contribute to water quality compliance in an efficient and convenient manner.

[0014] (2) In order to improve the strength and durability of the filter screen, reduce the risk of breakage, and allow workers to disassemble and replace worn parts, the filter screen is divided into dozens of segments connected together. Each segment of the filter screen is separated by a connecting ridge. Each segment of the filter screen is inserted into the connecting ridge by a fixing strip to form a continuous strip filter mechanism. The fixing strip and the connecting ridge can provide better resistance to torsion and other external forces in the form of reinforcing ribs.

[0015] (3) It creatively provides a variable adjustment device to realize stepless adjustment of the slab and area. It can adjust the ratio of the working area and the non-working area (maintenance area) as needed, and can adapt to the changes in water treatment peak and valley periods on an annual basis. During the valley period, the position of the water-blocking component in the box can be adjusted to control and reduce the size of the filter screen that can be used for filtration. At the same time, the adjustment component ensures that the filter screen will not detach from the connection of the active and driven pulleys, so that the filter screen always remains taut. Attached Figure Description

[0016] Figure 1 This is a top view of the prior art of the present invention.

[0017] Figure 2 This is a side view of the prior art of the present invention.

[0018] Figure 3 This is a front view schematic diagram of the prior art of the present invention.

[0019] Figure 4 This is a top view schematic diagram of some embodiments of the present invention.

[0020] Figure 5 This is a top view schematic diagram of another embodiment of the present invention.

[0021] Figure 6 This is a schematic diagram of the strip filter mechanism of the present invention.

[0022] Figure 7 For the present invention Figure 4 A three-dimensional schematic diagram.

[0023] Figure 8 This is a perspective view of some embodiments of the strip filter mechanism of the present invention.

[0024] Figure 9 This is a three-dimensional schematic diagram of some other embodiments of the strip filter mechanism of the present invention.

[0025] Figure 10 For the present invention Figure 9 A magnified three-dimensional schematic diagram of a portion of the structure.

[0026] Figure 11 For the present invention Figure 5 A three-dimensional schematic diagram.

[0027] Figure 12 This is a three-dimensional schematic diagram of the water-blocking component of the present invention in its installation state.

[0028] Figure 13 For the present invention Figure 11 A diagram illustrating the usage status.

[0029] Figure 14 This is a top view showing a comparison of the cross-sectional structures of waterproof membrane a and waterproof membrane b of the present invention.

[0030] Figure 15 This is a three-dimensional schematic diagram of the water baffle of the present invention.

[0031] Figure 16 This is a three-dimensional schematic diagram of the water baffle plate of the present invention after the electromagnet and the rubber strip are installed.

[0032] Figure 17 This is a three-dimensional schematic diagram of the adhesive strip of the present invention. Detailed Implementation

[0033] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0034] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0036] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] like Figures 1 to 3 As shown, the prior art of the present invention is illustrated. The prior art provides a cylindrical filter element that is tilted at a fixed angle within a water tank and partially submerged in water. Water to be filtered flows in from the bottom of the filter element, solid particles are intercepted, and the water can pass through the filter element and flow out from the outlet. As shown, the structural limitations mean that the amount of water to be treated in the MBR membrane tank during peak periods is greater than the average daily treatment capacity of the prior art.

[0039] In some embodiments of the present invention, structural limitations are overcome by using devices with conveying mechanisms or capable of cyclic filtration. For example, cyclic filtration devices can replace existing technologies through mechanisms that perform filtration via cyclic motion. The present invention continues the inventive concept and spirit of the prior art, improving upon it. For the sake of brevity, structural descriptions such as supports are omitted. Specifically, as follows... Figure 4There is a gap between the housing 1 and the filter screen 5 of the belt filter mechanism. In practice, this gap is filled by a bracket or frame, but it is not shown to clearly illustrate the contents of the drawing. Similar common methods in the prior art are all referenced to this, and while the description is omitted, they are implemented according to the prior art and are also included as part of a circulating filtration device.

[0040] like Figure 4 and Figure 7 As shown, in this embodiment, the length and width of the housing 1 are significantly increased. The appropriate distance between the drive shaft I3 and the driven shaft 4 is determined by the required sewage treatment volume. This embodiment still uses the existing power motor (i.e., the main motor 2 in this embodiment) to drive the output shaft (i.e., the drive shaft I3 in this embodiment) and the drive pulley to drive the filter screen 5 of the belt filter mechanism in this embodiment. The combination of the driven shaft 4 and the drive pulley is structurally identical to that of the drive shaft I3 and the drive pulley. Both the drive shaft I3 and the driven shaft 4 can be coaxially and rotatably mounted on the housing 1. As shown in the figure, the main motor 2 is set on both the drive shaft I3 and the driven shaft 4. This is to consider design redundancy and increase power backup within the limits of cost. If the motor of the drive shaft I3 fails, the main motor 2 on the driven shaft 4 will start, and the roles of the driven shaft 4 and the drive shaft I3 will be reversed.

[0041] The specific method by which the driving pulley and driven pulley drive the filter screen 5 can be implemented with reference to existing technology or other feasible methods. The use of friction or sprockets is not limited. This embodiment does not require excessive operational precision; the filter screen 5 only needs to be able to circulate. The filter screen 5 is made of a soft, deformable material and also needs to have a certain degree of corrosion resistance, such as polyester fiber.

[0042] In other embodiments, a variable adjustment device is also provided. The variable adjustment device drives the drive shaft I3 and / or the driven shaft 4 to slide through the motion component 7, shortening the distance between the driven shaft 4 and the drive shaft I3. The adjustment component is used to re-tension the filter screen that has lost tension due to the shortened distance between the driven shaft and the drive shaft I. The sliding support part 10 of the adjustment component slides through the sliding mechanism 28 of the motion component, and is always kept in a position close to the middle between the drive shaft I and the driven shaft. The main body 11 of the sliding support part 10 is connected to the sliding mechanism 28 through the support leg 12. In order to better support the weight of the sliding support part 10, the main body 11 can also be mounted on the top of the box wall. A slider is set in the area where the main body 11 contacts the top of the box wall to facilitate sliding on the top of the box. Since the slider has no active power, in order to reduce friction and ensure that the up and down movement of the main body 11 is as synchronous as possible, the slider can be made of a low-friction material, such as polytetrafluoroethylene (PTFE) or Teflon. The adjusting component 8 is used to re-tension the filter screen 5, which had become taut due to the shortening of the distance between the driven shaft 4 and the drive shaft I3. The shortening of the distance between the driven shaft 4 and the drive shaft I3 and the re-tensioning of the filter screen 5 by the adjusting component 8 are performed synchronously. Finally, the water-blocking component 6 is installed, which allows the processing area of ​​the tank 1 to be reduced as needed, forming a preset working area and maintenance area. During the off-peak water treatment period, maintenance can be carried out inside the tank 1, such as the annual anti-rust and anti-corrosion painting. Reducing the area of ​​the working area, and most importantly, can also reduce the speed and power of the main motor 2, saving electricity.

[0043] In this embodiment, the sliding mechanism 28 is mounted on the base 9, which is an extension of the spindle support frame in the prior art. The sliding mechanism 28 can adopt any feasible solution to drive the drive shaft I3 and the driven shaft 4 to slide along the base 9. It should be noted that this embodiment does not require the opening of a sliding window on the housing 1 for the drive shaft I3 and the driven shaft 4 to slide. The main motor 2 can be mounted above the housing 1 in a staggered arrangement similar to the letter Z with the drive shaft I3 through another transmission mechanism (such as a reducer), thereby achieving the effect of not needing to open a sliding window. However, this embodiment takes into account that the angle of the filter screen 5 is fixed, so the water level is usually fixed as well. By limiting the upper limit of the daily processing capacity and determining the width and angle of the filter screen 5, it can be ensured that the water level in the housing 1 will never overflow from the sliding window. Therefore, an example of opening a sliding window is shown in the figure, which also helps to simplify the transmission structure.

[0044] like Figure 5 , Figures 10 to 12As shown, when the filter screen 5 needs to be readjusted and re-tensioned, the auxiliary motor drives the swing arm 13 to swing in a circle, which in turn drives the tensioning wheel shaft 1414 to lift and tension the filter screen 5 that is about to sag. The tensioning wheel shaft 1414 can be able to rotate on the swing arm 13 or it can be fixed, and it can also be made of a low-friction material. The water baffle plate a15 of the water baffle assembly 6 can be fixed inside the housing 1 in any feasible way, and the sealing strip can also be fixed between the housing 1 and the water baffle plate a15 in any feasible way for watertight treatment. Figure 5 , Figures 14 to 17 As shown, the baffle plate a15 is preferably magnetically attached to the housing 1 by an electromagnet 19, and the gap is sealed with a sealing strip. In this embodiment, the baffle plate a15 is hollow inside and is vertically inserted into the housing 1. Except for the top, the other three sides of the baffle plate a15 are in contact with the housing 1. An opening 18 is made on the outer wall of the baffle plate a15, which is in contact with the housing 1, to accommodate the electromagnet 19. Through its hollow structure, the wires of the electromagnet 19 are introduced into the hollow interior of the baffle plate a15 through the opening 18, and then led out from the top of the baffle plate a15. Because of the magnetic attachment scheme using the electromagnet 19, the baffle plate a15 can be placed anywhere inside the housing 1 except for the inlet and outlet, allowing for relatively free adjustment of the area ratio of the partitions. Figures 11 to 13 As shown, a baffle plate b16 is also provided. The baffle plate b16 is not fixed to the tank 1 via magnetic attraction or other common connection methods. Instead, multiple grooves 17 are pre-cut inside the tank 1. The baffle plate b16 is inserted into the grooves 17 and fixed. Using the grooves 17 to fix the baffle plate b16 is simple and reliable when the water pressure is limited. Figures 14 to 17 As shown, except for the electromagnet 19, the wiring channel between the opening 18 and the interior of the baffle a15, and the power cord pulled out from the wiring channel extending from the outlet hole (not shown) at the top of the baffle a15, the remaining structure of the baffle a15 is the same as that of the baffle b16; in addition, a preferred sealing strip installation scheme is provided, namely in Figures 14 to 17Both the baffle plate a15 and b16 shown have a fixing groove 26 and a limiting flange 27. Taking the baffle plate a15 as an example, it not only has a recessed fixing groove 26 along its outer edge, but also a limiting flange 27 extending towards the edge of the baffle plate a15 on the outer side of the fixing groove 26. This limiting flange 27 extends along the fixing groove 26 and can serve as a structure for fixing, limiting, and guiding the sealing strip. A heating wire (not shown) can also be installed within the limiting flange 27. The heating wire is positioned at the contact point between the limiting flange 27 and the sealing strip. Based on the baffle plate a15, power can be drawn from the circuit of the electromagnet 19 and introduced from the hollow inner wall of the baffle plate a15 into the switching module of the heating wire within the limiting flange 27. Various necessary slots and holes need to be formed in the limiting flange 27 to accommodate the heating element and the circuit, which are not shown in this embodiment. When the water temperature is low in winter, the heating wire is activated to heat the sealing strip, causing it to expand and thus improving the sealing performance to some extent. However, a separate wiring connection is required for the heating wire on the b16 water baffle. During the installation of the water baffle assembly, work can be temporarily stopped and the water drained.

[0045] like Figure 6 , Figures 8 to 10 As shown, in some other embodiments, since the direction of the filter screen 5 can be adjusted by the variable adjustment device, the filter screen 5 needs to undergo multiple bends. To increase strength and improve durability, referring to the prior art scheme of using mesh-like plastic reinforcing ribs, a connecting ridge 20 and a fixing insert 21 are added to the strip filter mechanism. At the same time, the filter screen 5 is divided into dozens or even hundreds of segments, and a fixing insert 21 is fixedly attached to both sides of each segment of the filter screen 5. Slots 22 are opened on both sides of the connecting ridge 20. The slots 22 have an opening 23 on the outer side—that is, the edge of the slot 22 away from the connecting ridge 20—extending from the top of the slot wall to the bottom of the slot wall. The fixing insert 21 is inserted into the slot 22 from the top insertion opening 25. The bottom of the slot 22 faces the direction of the incoming water, so the bottom of the slot 22 is not open to prevent solid particles from easily entering the slot 22 and causing blockage. The filter screen 5 can rotate and swing within the opening 23 to better adapt to bending and other deformations. Preferably, to improve the stability of the fixing strip 21 within the slot 22 and prevent it from being forcibly pulled out of the slot 22 in extreme cases, a limiting rod 24 extending coaxially with the slot 22 is provided within the slot 22. Correspondingly, a limiting hole is formed at the bottom of the fixing strip 21 to mate with the limiting rod 24. The fixing strip 21 is fitted onto the limiting rod 24 through the limiting hole, limiting horizontal displacement. Then, a connector is used to fix the limiting hole and the limiting rod 24. It should be noted that the connector between the fixing limiting hole and the limiting rod 24 should not restrict the fixing strip 21 from rotating coaxially on the limiting hole, but only restrict the fixing strip 21 from detaching from the limiting rod 24.

Claims

1. A fine filtration device, comprising a housing, a main motor, a transmission mechanism, and a circulating filtration device, wherein the transmission mechanism includes at least a rotatable shaft mounted on the side wall of the housing, and the main motor drives the shaft to drive the circulating filtration device, which restricts the passage of target contaminants through cyclic rotation, characterized in that... The circulating filtering device comprises a belt conveying filtering assembly, the belt conveying filtering assembly comprises a belt filtering mechanism, a driving pulley and a driven pulley, and the rotating shaft comprises a driving shaft provided with the driving pulley and a driven shaft provided with the driven pulley, and the driving shaft and the driven shaft are kept apart. The belt filtering mechanism comprises a deformable filtering screen in the shape of a continuous belt and is tensioned by the driving pulley and the driven pulley, and the rotating shaft drives the filtering screen to perform a circulating movement.

2. The fine filter apparatus according to claim 1, wherein The variable adjusting device comprises a water blocking assembly, a movement assembly and an adjusting assembly, the movement assembly comprises a base and a sliding mechanism, the base is fixed to the side wall outside the box body, and the sliding mechanism is arranged on the base. The adjusting assembly comprises a sliding support and a swing arm, the main body of the sliding support is connected to the sliding mechanism through a supporting leg, one end of the swing arm can swing on the main body, the other end of the swing arm is provided with a tension pulley shaft, the tension pulley shaft can coaxially rotate on the connecting arm, and a secondary motor for driving the driving shaft II is further arranged on the main body. The water blocking assembly comprises a water blocking plate a and a sealing strip, a working area and a maintenance area are pre-set in the box body, the interval and position between the driving shaft and the driven shaft are adjusted, and the arrangement of the working area is matched; the filtering screen not tensioned between the driving shaft and the driven shaft is re-tensioned by using the tension pulley shaft; the water blocking plate a is vertically inserted into the box body and the gap between the water blocking plate a and the box body is detachably sealed by the sealing strip, so that different areas are separated; the water blocking plate a is hollow, a plurality of openings are formed in the end surface of the water blocking plate a in contact with the box body, an electromagnet is fixed in each opening, and the water blocking plate a is fixed in the box body by the electromagnet.

3. The fine filtration apparatus of claim 2, wherein, The water blocking assembly further comprises a water blocking plate b and a sealing strip; the water blocking plate b is hollow, a plurality of parallel strip-shaped grooves are formed in the box body, the grooves are formed along the inner wall of the box body and the extension direction of the grooves is perpendicular to the length direction of the box body, and the water blocking plate b is inserted into the grooves to separate the box body into the pre-set working area and maintenance area; the interval and position between the driving shaft and the driven shaft are adjusted, and the arrangement of the working area is matched; the filtering screen not tensioned between the driving shaft and the driven shaft is re-tensioned by using the tension pulley shaft.

4. The fine filter apparatus according to any one of claims 1 to 3, characterized by The belt filtering mechanism further comprises a connecting ridge and a fixed insertion strip, the fixed insertion strip is fixed to both ends of the filtering screen, the connecting ridge is provided with an insertion slot at both ends, the insertion slot is provided with a port extending along the length direction of the connecting ridge in the direction away from the connecting ridge, the top of the insertion slot is open and serves as an insertion port, the fixed insertion strip is inserted into the insertion slot through the insertion port, and the port is used to accommodate the filtering screen.

5. The fine filter apparatus according to claim 4, wherein The bottom of the insertion slot is further fixedly connected with a limiting rod, the limiting rod extends to the insertion port along the length direction of the connecting ridge, the bottom of the fixed insertion strip is provided with a limiting hole matched with the limiting rod, and the fixed insertion strip is sleeved on the limiting rod through the limiting hole and is fixed.

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