Alumina production wastewater filtering device

Abstract

The application discloses an alumina production wastewater filtering equipment, which comprises a cyclone separator cylinder, a cyclone separation assembly is arranged in the cyclone separator cylinder, the cyclone separator cylinder is composed of an upper cylindrical section and a conical section, the cyclone separation assembly comprises upper spiral plates and lower spiral plates, the upper spiral plates and the lower spiral plates are fixedly connected to the inner side of the cyclone separator cylinder, a lap joint cylinder is arranged at the top of the cyclone separator cylinder, a water outlet inner cylinder is rotatably lap jointed on the lap joint cylinder, and the bottom of the water outlet inner cylinder extends to a demarcation line between the upper cylindrical section and the conical section; a gap knocking assembly is arranged on the outer side of the conical section of the cyclone separator cylinder; through the design of multistage spiral flow guide, optimized flow field, gap knocking, anti-blocking stirring and automatic slag discharge, the application can significantly improve the separation efficiency, effectively prevent the slag discharge port from being blocked, prolong the service life of the equipment, improve the automation degree and operation convenience of the equipment, reduce the production cost and ensure the continuity of production.

Description

Technical Field

[0001] This invention relates to the technical field of centrifugal separation, specifically to a wastewater filtration device for alumina production. Background Technology

[0002] Alumina production wastewater is characterized by its complex composition, high concentration of suspended solids, and the presence of red mud particles, alkaline solutions, and colloidal substances, as well as its strong corrosiveness. Traditional filtration equipment often employs gravity sedimentation, centrifugal separation, or inertial separation technologies. Among these, centrifugal separation technology is often used in cyclone separators due to its high treatment efficiency. The centrifugal force generated by high-speed rotation can effectively separate red mud particles from the wastewater. However, traditional cyclone separators have revealed significant shortcomings in practical applications:

[0003] Existing cyclone separators lack efficient cyclone separation components, making it difficult to fully separate solid particles and resulting in low separation efficiency. This leads to a still high suspended solids content in wastewater. The bottom of the cyclone separator has an inverted conical structure, meaning the discharge port diameter is too small. High-concentration red mud particles and colloidal substances easily stick together and clump together, causing blockage of the discharge port. This requires daily shutdown for high-pressure water flushing, affecting continuous production. Summary of the Invention

[0004] The purpose of this invention is to provide a wastewater filtration device for alumina production, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a wastewater filtration device for alumina production, comprising a cyclone separator cylinder, a cyclone separation component disposed within the cyclone separator cylinder, the cyclone separator cylinder being composed of an upper cylindrical section and a conical section, the cyclone separation component comprising an upper spiral plate and a lower spiral plate, the upper spiral plate and the lower spiral plate being fixedly connected to the inner side of the cyclone separator cylinder, an overlapping cylinder being disposed at the top of the cyclone separator cylinder, an outlet inner cylinder being rotatably overlapped on the overlapping cylinder, the bottom of the outlet inner cylinder extending to the dividing line between the upper cylindrical section and the conical section, and a spiral plate being disposed on the outer side of the outlet inner cylinder;

[0006] The outer side of the conical section of the cyclone separator cylinder is provided with a gap striking assembly. The gap striking assembly includes a support base, a rotating shaft is rotatably connected to the support base via a support block, and a striking block is fixedly sleeved on the rotating shaft. The striking part of the striking block is close to the outer side of the bottom of the conical section. The rotation of the cyclone separator centrifuges the wastewater, and the striking block achieves gap striking of the outer side of the bottom of the conical section by adjusting the transmission of the assembly.

[0007] The bottom of the cyclone separator cylinder is provided with an anti-clogging stirring assembly, which includes a transition cover. A drive shaft is rotatably connected to the transition cover, and a stirring plate is provided on the drive shaft. The transition cover has an arc cavity structure, and the end of the stirring plate extends to the part above the parallel line at the bottom of the conical section.

[0008] Preferably, the cyclone separator cylinder has a tangential inlet on its side, which is directly opposite the water outlet cylinder. A first annular groove is provided at the top edge of the water outlet cylinder, and an arc block is provided on the outer side of the top of the water outlet cylinder.

[0009] Preferably, the adjustment assembly includes a receiving seat, which is fixedly installed on the top of the cyclone separator cylinder, and a top block is slidably inserted into the receiving seat.

[0010] Preferably, the end of the top block has an inclined surface structure, and the end penetrates through the overlapping cylinder and corresponds to the arc block. The movement trajectory of the arc block forms an annular groove, which is opened on the inner side of the overlapping cylinder.

[0011] Preferably, a first airbag is provided between the top block and the receiving seat, a connecting tube is provided at the end of the first airbag, a gear is provided on the rotating shaft, a fixed seat is provided at the bottom of the rotating shaft, the fixed seat has a groove, an installation block is provided at the opening of the groove, and a rack block is slidably inserted into the groove.

[0012] Preferably, the rack block meshes with the gear, a return spring is provided between the rack block and the groove, a second airbag is provided between the mounting block and the groove, and the second airbag is connected to the connecting pipe.

[0013] Preferably, the bottom of the transition cover is provided with a waste residue outlet pipe, a collection cylinder is screwed onto the waste residue outlet pipe, and a limit ring is provided on the outside of the waste residue outlet pipe.

[0014] Preferably, a pressure sensor is provided on the limiting ring, and the pressure sensor is electrically connected to the control center. A switching valve is provided inside the waste residue outlet pipe, and the switching valve is electrically connected to the control center.

[0015] Preferably, the waste outlet pipe is provided with an external thread, and the inner side of the end of the collection cylinder is provided with an internal thread, and the external thread and the internal thread are threadedly connected.

[0016] Preferably, the end of the arc block has a semi-circular arc structure, the overlapping cylinder has a stepped cylindrical structure, and a second annular groove is provided at the top. Both the first and second annular grooves are inlaid with sealing rings.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. This invention utilizes the combined use of an upper and lower spiral plate, along with a spiral plate on the outer side of the effluent inner cylinder, to form a multi-stage spiral flow guiding system. The upper spiral plate creates the initial vortex, while the lower spiral plate extends the vortex path, increasing the probability of particle collision and sedimentation. The spiral plate on the outer side of the effluent inner cylinder further stabilizes the flow field around the inner cylinder, preventing separated solid particles from being rolled up again and improving the quality of the effluent. This multi-stage spiral flow guiding design is more efficient than the traditional single vortex design, and can more effectively guide solid particles in wastewater to the cylinder wall, where they move downwards under centrifugal force, achieving solid-liquid separation.

[0019] 2. This invention provides a gap-knocking component, including a support base, a rotating shaft, and a knocking block, installed on the outer side of the conical section of the cyclone separator cylinder. By adjusting the transmission of the component, the rotation of the cyclone separator component can drive the knocking block to knock the outer side of the bottom of the conical section with gaps, thereby destroying the particle adhesion layer on the inner side of the bottom of the conical section and preventing material accumulation and blockage. This active anti-blocking design avoids the passive method of relying on manual or high-pressure water flushing in traditional designs, and improves the reliability and continuous operation capability of the equipment.

[0020] 3. This invention features a pressure sensor and a switching valve installed on the waste residue outlet pipe, electrically connected to the control center. The pressure sensor detects the pressure at which the collection cylinder is installed and transmits the signal to the control center. When the collection cylinder is in place, the pressure sensor detects the pressure, and the control center controls the switching valve to open and discharge the waste residue. When the collection cylinder needs to be replaced, the pressure sensor does not detect the pressure, and the control center controls the switching valve to close the waste residue outlet pipe, eliminating the need to stop the machine. This automatic waste residue discharge design improves the automation level of the equipment, reduces labor costs, and ensures continuous production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the alumina production wastewater filtration equipment of the present invention.

[0022] Figure 2 This is a schematic diagram of the waste residue outlet pipe of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of the collection tube of the present invention.

[0024] Figure 4 This is a schematic diagram of the structure of the receiving seat and the support seat of the present invention.

[0025] Figure 5 This is a schematic diagram of the cyclone separator component of the present invention.

[0026] Figure 6 This is a cross-sectional view of the transition cover of the present invention.

[0027] Figure 7 This is a cross-sectional view of the housing of the present invention.

[0028] Figure 8 For the present invention Figure 7 Enlarged structural diagram at point A in the middle.

[0029] Figure 9 This is a cross-sectional view of the fixing base of the present invention.

[0030] Figure 10 For the present invention Figure 9 Enlarged structural diagram at point B.

[0031] In the diagram: Cyclone separator cylinder 1; upper spiral plate 11; lower spiral plate 12; tangential inlet 2; water outlet inner cylinder 3; first annular groove 31; arc block 32; spiral plate 33; overlapping cylinder 4; second annular groove 41; transition cover 5; drive shaft 51; stirring plate 52; waste residue outlet pipe 6; external thread 61; switch valve 62; limit ring 63; pressure sensor 64; collection cylinder 7; internal thread 71; receiving seat 8; top block 81; first airbag 82; connecting pipe 83; support seat 9; rotating shaft 91; gear 92; striking block 93; fixed seat 94; reset spring 95; second airbag 96; mounting block 97; rack block 98. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figure 1 This is a schematic diagram of the structure of the alumina production wastewater filtration equipment of the present invention. Figure 5 This is a schematic diagram of the cyclone separation component of the present invention. The present invention provides a technical solution: a wastewater filtration device for alumina production, including a cyclone separator cylinder 1, in which a cyclone separation component is installed. The cyclone separator cylinder 1 is composed of an upper cylindrical section and a conical section, providing space for the entire separation process. The upper cylindrical section contains high-speed rotating wastewater and uses centrifugal force to initially separate solid particles. The conical section accelerates the downward movement of the fluid through a tapered structure, enhancing the settling efficiency of solid particles. The cyclone separator cylinder 1 is made of wear-resistant alloy steel lined with a ceramic coating to resist the scouring of high-speed particles.

[0034] The cyclone separator assembly includes an upper spiral plate 11 and a lower spiral plate 12. The upper spiral plate 11 and the lower spiral plate 12 are fixedly connected to the inner side of the cyclone separator cylinder 1. The upper spiral plate 11 is fixed to the inner side of the cylinder and guides the wastewater to form an initial vortex. The lower spiral plate 12 is connected to the upper spiral plate 11 to extend the vortex path and increase the probability of particle collision and sedimentation. The upper spiral plate 11 and the lower spiral plate 12 can guide the wastewater, enhance the vortex effect, and improve the separation efficiency. The design of the spiral plates can more effectively guide the solid particles in the wastewater to the cylinder wall and move downward under the action of centrifugal force to achieve solid-liquid separation.

[0035] The combined use of the upper spiral plate 11 and the lower spiral plate 12, along with the spiral plate 33 on the outside of the inner cylinder 3, constitutes a multi-stage spiral flow guiding system. The upper spiral plate forms the initial vortex, the lower spiral plate extends the vortex path, and increases the probability of particle collision and sedimentation. The spiral plate 33 on the outside of the inner cylinder 3 further stabilizes the flow field around the inner cylinder, preventing the separated solid particles from being rolled up again and improving the quality of the effluent. This multi-stage spiral flow guiding design is more efficient than the traditional single vortex design, and can more effectively guide the solid particles in the wastewater to the cylinder wall and move downward under the action of centrifugal force to achieve solid-liquid separation.

[0036] The top of the cyclone separator cylinder 1 is fixedly connected to an overlapping cylinder 4, and an outlet inner cylinder 3 is rotatably connected to the overlapping cylinder 4. The bottom of the outlet inner cylinder 3 extends to the dividing line between the upper cylindrical section and the conical section. The outlet inner cylinder 3 collects the upward-moving clean water and guides it to the top for discharge. The design of extending the bottom to the dividing line can more effectively collect the separated clean water and reduce the influence of short-circuit flow. A spiral plate 33 is fixedly connected to the outside of the outlet inner cylinder 3. The spiral plate 33 further stabilizes the flow field around the inner cylinder, prevents the separated solid particles from being rolled up again, and improves the quality of the effluent. At the same time, the wastewater can drive the rotation of the outlet inner cylinder 3, further enhancing the swirling effect.

[0037] Figure 4 The diagram shows the structure of the receiving seat and the support seat of the present invention. A gap striking component is provided on the outer side of the conical section of the cyclone separator cylinder 1. The gap striking component prevents material accumulation on the inner side of the bottom of the conical section and avoids blockage. The gap striking component includes a support seat 9. A rotating shaft 91 is rotatably connected to the support seat 9 via a support block. A striking block 93 is fixedly sleeved on the rotating shaft 91. The striking part of the striking block 93 is close to the outer side of the bottom of the conical section. The rotation of the cyclone separator component is achieved by adjusting the transmission of the component to make the striking block 93 intermittently strike the outer side of the bottom of the conical section.

[0038] Figure 6This is a cross-sectional view of the transition cover of the present invention. The bottom of the cyclone separator cylinder 1 is provided with an anti-clogging stirring assembly. The anti-clogging stirring assembly includes a transition cover 5. A drive shaft 51 is rotatably connected to the transition cover 5. A motor is installed at the end of the drive shaft 51. The start of the motor drives the drive shaft 51 to rotate. A stirring plate 52 is fixedly connected to the drive shaft 51. The transition cover 5 has an arc cavity structure. The end of the stirring plate 52 extends to the part above the parallel line of the bottom end of the cone section. The stirring plate 52 stirs the wastewater at the bottom of the cone section to prevent solid particles from depositing and clogging.

[0039] A tangential inlet 2 is connected to the side of the cyclone separator cylinder 1. The tangential inlet 2 is directly opposite the outlet inner cylinder 3. The tangential inlet 2 is connected to a wastewater inlet pipe. Wastewater in the wastewater inlet pipe is pumped into the cyclone separator cylinder 1 through the tangential inlet 2 by a conveying pump, so that the wastewater enters the cylinder 1 at a tangential velocity. A first annular groove 31 is opened at the top edge of the outlet inner cylinder 3. An arc block 32 is fixedly connected to the outer side of the top of the outlet inner cylinder 3.

[0040] The end of the arc block 32 is a semi-circular arc structure, the overlapping cylinder 4 is a stepped cylindrical structure, and a second annular groove 41 is opened at the top. Both the first annular groove 31 and the second annular groove 41 are embedded with sealing rings. The sealing rings ensure the sealing between the water outlet inner cylinder 3 and the overlapping cylinder 4 to prevent wastewater leakage. The overlapping cylinder 4 is fixedly connected to the subsequent treatment pipeline, which is not shown in the attached figure, so that the clean water goes out from the water outlet inner cylinder 3 and enters the subsequent pipeline for subsequent processes.

[0041] Figure 7 This is a cross-sectional view of the housing of the present invention. Figure 8 For the present invention Figure 7 The enlarged structural diagram at point A shows that the adjustment component includes a receiving seat 8, which is fixedly installed on the top of the cyclone separator cylinder 1. A top block 81 is slidably inserted into the receiving seat 8. The end of the top block 81 has an inclined surface structure and the end passes through the overlapping cylinder 4 and corresponds to the arc block 32. The movement trajectory of the arc block 32 forms an annular groove, which is opened on the inner side of the overlapping cylinder 4. A first airbag 82 is bonded between the top block 81 and the receiving seat 8. The end of the first airbag 82 is connected to a connecting pipe 83.

[0042] The rotation of the inner cylinder 3 causes the arc block 32 to periodically compress the top block 81. The rotation of the arc block 32 abuts against the inclined surface of the top block 81, causing the top block 81 to move into the receiving seat 8, squeezing the first air bladder 82. The gas in the first air bladder 82 is transmitted through the connecting pipe 83.

[0043] Figure 9 This is a cross-sectional view of the fixing base of the present invention. Figure 10 For the present invention Figure 9The enlarged structural diagram at point B shows a gear 92 fixedly sleeved on a rotating shaft 91. A fixed base 94 is fixedly connected to the bottom of the rotating shaft 91. The fixed base 94 has a groove, and a mounting block 97 is fixed to the opening of the groove by screws. A rack block 98 is slidably inserted into the groove, and the rack block 98 meshes with the gear 92. A return spring 95 is fixedly connected between the rack block 98 and the groove. A second airbag 96 is bonded between the mounting block 97 and the groove. The second airbag 96 is connected to the connecting pipe 83. The model and specifications of the second airbag 96 and the first airbag 82 can be selected according to the specific working conditions.

[0044] When the gas in the first airbag 82 is transmitted to the second airbag 96 through the connecting pipe 83, the second airbag 96 expands and compresses the movement of the rack block 98, thereby driving the gear 92 and the rotating shaft 91 to rotate, driving the striking block 93 to strike the bottom of the cone section, thereby destroying the particle adhesion layer on the inner side of the bottom of the cone section.

[0045] By adjusting the drive of the components, the rotation of the cyclone separator can drive the striking block 93 to strike the outer bottom of the cone section, thereby breaking the particle adhesion layer on the inner bottom of the cone section and preventing material accumulation and blockage. This active anti-clogging design avoids the passive method of relying on manual or high-pressure water flushing in traditional designs, improving the reliability and continuous operation capability of the equipment.

[0046] Figure 2 This is a schematic diagram of the waste residue outlet pipe of the present invention. Figure 6 This is a cross-sectional view of the transition cover of the present invention. Figure 3 The diagram shows the structure of the collection cylinder of the present invention. A waste slag outlet pipe 6 is welded to the bottom of the transition cover 5. The transition cover 5 forms a transition space, providing space for the rotation of the stirring plate 52 and guiding the waste slag to the waste slag outlet pipe 6. A collection cylinder 7 is screwed onto the waste slag outlet pipe 6. A limit ring 63 is fixedly connected to the outside of the waste slag outlet pipe 6. The drive shaft 51 drives the stirring plate 52 through the motor to continuously agitate the bottom slurry to prevent caking. The waste slag is introduced into the waste slag outlet pipe 6 through the transition cover 5.

[0047] A pressure sensor 64 is installed on the limit ring 63 and is electrically connected to the control center. A switch valve 62 is installed inside the waste slag outlet pipe 6 and is electrically connected to the control center. An external thread 61 is welded on the waste slag outlet pipe 6, and an internal thread 71 is welded on the inner side of the end of the collection cylinder 7. The external thread 61 and the internal thread 71 are threaded together. The pressure sensor 64 detects the pressure of the collection cylinder 7 during installation and transmits the signal to the control center to control the opening and closing of the switch valve 62. When the collection cylinder 7 is replaced, if the pressure sensor 64 does not detect pressure, the control center controls the switch valve 62 to close the waste slag outlet pipe 6 without stopping the machine. This automatic slag discharge design improves the automation level of the equipment, reduces labor costs, and ensures the continuity of production.

[0048] In actual use, wastewater enters the cyclone separator cylinder 1 at high speed through the tangential inlet 2. The tangential velocity triggers centrifugal swirling, and solid particles are thrown against the cylinder wall under centrifugal force, settling along the conical section. Clean water gathers towards the center and is discharged through the inner outlet cylinder 3. The upper spiral plate 11 and lower spiral plate 12 extend the fluid path, increasing the probability of particle collision. The spiral plate 33 of the inner outlet cylinder 3 suppresses secondary entrainment. When the inner outlet cylinder 3 rotates, the rotation drives the arc block 32 to periodically compress the top block 81. The rotation of the arc block 32 abuts against the inclined surface of the top block 81, causing the top block 81 to move into the receiving seat 8, squeezing the first air bladder 82. The gas in the first air bladder 82 is transmitted to the second air bladder 96 through the connecting pipe 83. The second air bladder 96 expands, squeezing the movement of the rack block 98, which in turn drives the gear 92 and the rotating shaft 91 to rotate, driving the striking block 93 to strike the bottom of the conical section. The particle adhesion layer on the inner side of the bottom of the cone section is destroyed. The drive shaft 51 drives the stirring plate 52 through the motor to continuously agitate the bottom slurry to prevent caking. The waste residue is introduced into the waste residue outlet pipe 6 through the transition cover 5, which can effectively prevent the deposition and caking of solid particles at the bottom of the cone section and ensure the smooth flow of the slag discharge port. After the collection cylinder 7 is fixed by the threaded connection, the pressure sensor 64 detects the position signal and sends it to the control center. The control center controls the switch valve 62 to open the slag discharge. When the collection cylinder 7 is replaced, if the pressure sensor 64 does not detect pressure, the control center controls the switch valve 62 to close the waste residue outlet pipe 6. Through the design of multi-stage spiral flow guidance, optimized flow field, gap knocking, anti-clogging stirring and automatic slag discharge, the separation efficiency is significantly improved, the slag discharge port is effectively prevented from being blocked, the service life of the equipment is extended, the automation level and ease of operation of the equipment are improved, the production cost is reduced, and the continuity of production is guaranteed.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wastewater filtration device for alumina production, comprising a cyclone separator cylinder, characterized in that: The cyclone separator cylinder is equipped with a cyclone separation component. The cyclone separator cylinder is composed of an upper cylindrical section and a conical section. The cyclone separation component includes an upper spiral plate and a lower spiral plate. The upper spiral plate and the lower spiral plate are fixedly connected to the inner side of the cyclone separator cylinder. The top of the cyclone separator cylinder is equipped with an overlapping cylinder. An outlet inner cylinder is rotatably overlapped on the overlapping cylinder. The bottom of the outlet inner cylinder extends to the dividing line between the upper cylindrical section and the conical section. A spiral plate is provided on the outer side of the outlet inner cylinder. A gap-knocking assembly is provided on the outer side of the conical section of the cyclone separator cylinder. The gap-knocking assembly includes a support base, a rotating shaft is rotatably connected to the support base via a support block, and a knocking block is fixedly sleeved on the rotating shaft. The knocking part of the knocking block is close to the outer side of the bottom of the conical section. The rotation of the cyclone separator centrifuges the wastewater, and the knocking block knocks the outer side of the bottom of the conical section at intervals by adjusting the transmission of the assembly. The adjustment assembly includes a receiving seat, which is fixedly installed on the top of the cyclone separator cylinder. A top block is slidably inserted into the receiving seat. A first airbag is provided between the top block and the receiving seat. A connecting pipe is provided at the end of the first airbag. A gear is provided on the rotating shaft. A fixed seat is provided at the bottom of the rotating shaft. The fixed seat has a groove. An installation block is provided at the opening of the groove. A rack block is slidably inserted into the groove. The rack block meshes with the gear. A return spring is provided between the rack block and the groove. A second airbag is provided between the installation block and the groove. The second airbag is connected to the connecting pipe. The bottom of the cyclone separator cylinder is equipped with an anti-clogging stirring assembly, which includes a transition cover. A drive shaft is rotatably connected to the transition cover, and a stirring plate is installed on the drive shaft. The transition cover has an arc cavity structure, and the end of the stirring plate extends to the part above the parallel line at the bottom of the cone section. The bottom of the transition hood is equipped with a waste residue outlet pipe, and a collection cylinder is screwed onto the waste residue outlet pipe. A limit ring is installed on the outside of the waste residue outlet pipe, and a pressure sensor is installed on the limit ring. The pressure sensor is electrically connected to the control center. A switch valve is installed inside the waste residue outlet pipe, and the switch valve is electrically connected to the control center. The waste residue outlet pipe is equipped with an external thread, and the inner side of the end of the collection cylinder is equipped with an internal thread. The external thread and the internal thread are threaded together.

2. The alumina production wastewater filtration equipment according to claim 1, characterized in that: The cyclone separator cylinder has a tangential inlet on its side, which faces the water outlet cylinder. A first annular groove is provided at the top edge of the water outlet cylinder, and an arc block is provided on the outer side of the top of the water outlet cylinder.

3. The alumina production wastewater filtration equipment according to claim 1, characterized in that: The top block has an inclined surface structure at its end, and the end passes through the overlapping cylinder and corresponds to the arc block. The movement trajectory of the arc block forms an annular groove, which is opened on the inner side of the overlapping cylinder.

4. The alumina production wastewater filtration equipment according to claim 2, characterized in that: The ends of the arc block are semi-circular arc structures, the overlapping cylinder is a stepped cylindrical structure, and a second annular groove is provided at the top. Both the first and second annular grooves are embedded with sealing rings.

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