A waste heat recovery device for sintering a ferrite magnetic ring

Abstract

The application discloses a kind of ferrite magnetic ring sintering waste heat recovery device, belong to ferrite magnetic ring processing related technical field, including fan, first flue and second flue, the fan fixed installation is in the upper end middle position of sintering furnace, the first flue fixed installation is in the outer surface of one side of fan, the second flue fixed installation is in the outer surface of the other side of fan, the outer surface of the second flue is fixedly sleeved with filter cover, the air outlet end of the second flue is connected with drying box, the inside of the drying box is installed with several groups of tray, the inside of the filter cover is movably installed with telescopic cover, the air outlet end of the first flue and sintering furnace are connected;The waste heat generated when sintering furnace is used is secondly shunted, in early stage link, moisture in magnetic ring blank is removed using waste heat, the drying treatment of ferrite magnetic ring early stage is completed, and the sintering furnace waste heat utilization rate is effectively improved.

Description

Technical Field

[0001] This invention belongs to the technical field of ferrite magnetic ring processing, specifically a waste heat recovery device for ferrite magnetic ring sintering. Background Technology

[0002] This ferrite magnetic ring sintering waste heat recovery device uses a heat collection flue to draw clean hot air at 300-600℃ from the induced draft fan. The air is then transported to the preheating section at the front of the kiln through a high-temperature resistant square air pipe and evenly introduced into the kiln through distributed air spray pipes. The waste heat is used to directly preheat and degrease the green rings, which significantly reduces the power or gas consumption of the main heating section and effectively avoids the risk of cracking of the green rings due to sudden heating. At the same time, in conjunction with the heat preservation pipeline and temperature control cooling system, a stable closed loop of thermal parameters in the kiln is achieved.

[0003] Patent document CN108731489B describes a waste heat recovery device for a sintering furnace, including a sintering furnace, a tempering box, and a waste heat recovery mechanism. The waste heat recovery mechanism includes a box body, a first guide rail fixed inside the box body, a first heat dissipation box slidably connected to the first guide rail, a first spring fixed between the first heat dissipation box and the box body, a first partition and a second partition fixed on one side inside the first heat dissipation box, a first channel formed between the first partition and the bottom of the first heat dissipation box, a first baffle slidably connected inside the first channel, a second spring fixed between the first baffle and the side wall of the first heat dissipation box; a second channel is formed between the first partition and the second partition, a second baffle slidably connected inside the second channel, a third spring fixed between the second baffle and the side wall of the first heat dissipation box.

[0004] Existing waste heat recovery devices have certain shortcomings in use. Traditional ferrite magnetic ring sintering waste heat recovery devices generally adopt a simple circulation mode of "direct extraction from the cooling zone - direct delivery to the kiln front," that is, the high-temperature airflow from the cooling section of the sintering furnace is extracted by an induced draft fan and directly fed back to the preheating area at the front of the kiln to participate in the preheating of green billets. This single-loop design has obvious shortcomings in energy utilization. The hot air only acts on the narrow preheating section inside the kiln and cannot extend to the external processes, resulting in a large amount of low-grade waste heat not being utilized in stages. In particular, it lacks a special drying pretreatment function for the magnetic ring billets before entering the kiln. Secondly, the extracted hot air often carries dust particles such as kiln body debris, ferrite powder, and volatile binder residues. If this dust-laden hot air is directly used for drying the billets, it is very easy for impurities to be physically adsorbed and embedded on the surface of the green billets. These deposits will evolve into the source of pores, spots, and even micro-cracks during subsequent high-temperature sintering, seriously deteriorating the density and permeability of the magnetic rings. Summary of the Invention

[0005] This invention provides a waste heat recovery device for ferrite magnetic ring sintering, which solves the problem of the simple circulation mode of "direct extraction from the cooling zone to direct delivery to the kiln front" commonly used in existing ferrite magnetic ring sintering waste heat recovery devices. This mode involves drawing high-temperature airflow from the cooling section of the sintering furnace using an induced draft fan and directly returning it to the preheating zone at the front of the kiln to participate in the preheating of the green body. This single-loop design has significant energy utilization limitations; the hot air only acts on the narrow preheating section inside the kiln and cannot extend to processes outside the kiln, resulting in a large amount of low-grade waste heat not being utilized in a cascade manner. A waste heat recovery device for ferrite magnetic ring sintering includes a fan, a first flue, and a second flue. The fan is fixedly installed at the upper middle position of the sintering furnace. The first flue is fixedly installed on one side of the outer surface of the fan, and the second flue is fixedly installed on the other side of the outer surface of the fan. A filter sleeve is fixedly fitted onto the outer surface of the second flue. A drying box is connected through the outlet end of the second flue. Several sets of trays are installed inside the drying box. A telescopic sleeve is movably installed inside the filter sleeve. The outlet end of the first flue is connected through the sintering furnace.

[0006] As a further technical solution of the present invention, valves are installed at the exhaust ends of both the first and second flues. An exhaust nozzle is provided on one side of the second flue. During operation, the waste heat generated during the operation of the sintering furnace can be transferred back to the interior of the sintering furnace to heat the ferrite magnetic rings inside the sintering furnace. The first flue draws hot air of 300 to 600 degrees Celsius from the sintering furnace and transports it to the heating zone of the sintering furnace, i.e., the preheating section, through the first flue. The hot air is then reintroduced into the kiln through evenly distributed air jets. The waste heat is directly used to perform gradient preheating and degreasing of the ferrite magnetic ring green billets. This not only significantly reduces the consumption of gas or electricity in the main heating section, but also avoids cracking of the green billets through precise temperature control, realizing closed-loop utilization of heat circulation in the kiln and improving energy efficiency.

[0007] As a further technical solution of the present invention, the valve and the exhaust nozzle are connected in a continuous manner. A flow equalization plate is fixedly installed on the outer surface of one end of the exhaust nozzle, and several sets of partition plates are fixedly installed on the inner side of the flow equalization plate. During operation, the excess heat in the sintering furnace is extracted by the fan, and a portion of the hot air is transported to the interior of the drying box through the second flue. In the ferrite magnetic ring processing stage, the ferrite magnetic ring blank can be dried and dehydrated. The setting of the flow equalization plate can evenly discharge the hot air discharged from the exhaust nozzle upward. The exhaust nozzle and the flow equalization plate are connected by air passages corresponding to the number of partition plates, so that the hot air discharged from the exhaust nozzle is guided to each set of partition plates. The hot air is evenly discharged upward through the flow equalization plate to dry and dehydrate the ferrite magnetic ring blank in the tray.

[0008] As a further technical solution of the present invention, a mesh plate is fixedly installed on the upper outer surface of the flow equalization plate. The flow equalization plate is fixedly installed at the lower end of the inside of the drying box. The mesh plate is used to disperse the hot air a second time to avoid heat accumulation. The flow equalization plate is set at the bottom position, and the hot air is discharged upward through the flow equalization plate, so that the ferrite magnetic ring blanks in several trays can be dried evenly.

[0009] As a further technical solution of the present invention, a number of sliding frames are movably installed on the inner side of the tray. The two ends of the sliding frames are slidably connected to the tray through sliding grooves. The sliding grooves are set on the inner side of the tray. During operation, the ferrite magnetic ring blank to be dried is placed on the upper end of the sliding frame. Then, by sliding the sliding frame, the sliding frame moves along the sliding groove of the tray, so that the two sets of sliding frames have a certain distance. At the same time, the upper and lower sliding frames are staggered. This allows the hot air discharged from the equalization plate to pass through the sliding frames of the tray, so that the ferrite magnetic ring blank and the hot air can fully contact each other, and the lower tray is prevented from blocking the heat transfer.

[0010] As a further technical solution of the present invention, both outer surfaces of the filter sleeve are provided with transverse push rods. The filter sleeve and the telescopic sleeve are driven by the transverse push rods. During operation, the filter sleeve can filter impurities in the air when hot air passes through the filter, and the transverse push rods drive the telescopic sleeve to move, so that the filter sleeve can have a filter switching function.

[0011] As a further technical solution of the present invention, two sets of filters are spliced ​​and installed on the inner side of the telescopic sleeve, and sealing caps are fixedly installed on the outer surfaces of both ends of the telescopic sleeve. The user can directly insert the filter into the slot of the telescopic sleeve to complete the replacement of the filter. The sealing cap can improve the sealing performance after the telescopic sleeve is moved and adjusted.

[0012] As a further technical solution of the present invention, an airtight frame is fixedly installed at the middle position of the outer surface of the telescopic sleeve, and two sets of filters are respectively located on both sides of the airtight frame. When the telescopic sleeve is moved and switched, the airtight frame can be sealed and connected with the inner sides of both ends of the filter sleeve to prevent hot air from overflowing from the gap between the filter sleeve and the telescopic sleeve when passing through the filter sleeve.

[0013] As a further technical solution of the present invention, a sealing ring is provided on one outer surface of the sealing cover and on both outer surfaces of the airtight frame. A U-shaped groove is provided on both inner and outer surfaces of the filter sleeve to cooperate with the sealing ring. When the filter is switched, the horizontal push rod is an electric push rod. The horizontal push rod drives the telescopic sleeve to move to one side, removing the used filter from the inside of the filter sleeve. At the same time, the replacement filter is moved into the inside of the filter sleeve. At this time, the sealing ring on one side of the sealing cover aligns with the U-shaped groove on the outside of the filter sleeve, while the sealing ring at the corresponding position of the airtight frame aligns with the U-shaped groove on the inside of the filter sleeve. This ensures that the telescopic sleeve remains sealed after adjustment. In addition, the airtight frame, in conjunction with the use of two sets of sealing covers, allows the two sets of sealing rings and U-shaped grooves to align when the telescopic sleeve moves to one side or the other.

[0014] As a further technical solution of the present invention, the sealing ring has an overall U-shaped structure, and the sealing ring and the U-shaped groove fit together.

[0015] The beneficial effects of the present invention are as follows: By setting up a second flue and a drying box, the waste heat recovery device for ferrite magnetic ring sintering can perform secondary diversion of the waste heat generated during the use of the sintering furnace, use the waste heat to remove moisture from the magnetic ring blank, improve the pass rate, complete the early drying treatment of the ferrite magnetic ring, and effectively improve the waste heat utilization rate of the sintering furnace. In daily operation, excess heat is extracted from the sintering furnace using a blower, and some of the hot air is transported to the interior of the drying chamber through the second flue. During the ferrite magnetic ring processing, the ferrite magnetic ring blanks can be dried and dehydrated. The uniform flow plate ensures that the hot air from the exhaust nozzles is evenly discharged upwards. The exhaust nozzles and the uniform flow plate are connected by air ducts corresponding to the number of partition plates, guiding the hot air from the exhaust nozzles to each set of partition plates. The uniform flow plate then evenly discharges the hot air upwards, and the mesh plate further disperses the hot air, preventing heat accumulation. Next, the ferrite magnetic ring blanks to be dried are... The ferrite magnetic ring blank is placed on the upper end of the sliding frame. The sliding frame moves along the groove of the tray, so that the two sets of sliding frames have a certain distance. This allows hot air to pass through the space between the two sets of sliding frames and move upward. At the same time, the upper and lower sliding frames are staggered, which allows the hot air discharged from the equalizing plate to pass through the sliding frames of several trays. This ensures full contact between the ferrite magnetic ring blank and the hot air, and prevents the lower tray from blocking the heat transfer. This dries and dehydrates the ferrite magnetic ring blank in the tray, making the heating of the multi-layer ferrite magnetic ring blank more uniform. By setting up a filter sleeve, the use of the second flue is optimized when the waste heat recovery device for ferrite magnetic ring sintering is used. Under the premise of ensuring its airtightness, it has a movable switching hot air filtration structure, which effectively removes impurities in the hot air, extends its service life, and improves the drying quality of the ferrite magnetic ring blank. During operation, hot air in the second flue passes through the filter, removing impurities and trapping them inside. After a period of use, the filter is switched. The horizontal push rod is an electric push rod, which drives the telescopic sleeve to move to one side, removing the used filter from the inside of the filter sleeve. At the same time, the replacement filter is moved into the inside of the filter sleeve. At this time, the sealing ring on one side of the sealing cover aligns with the U-shaped groove on the outside of the filter sleeve, while the sealing ring at the corresponding position of the airtight frame aligns with the U-shaped groove on the inside of the filter sleeve. This ensures that the telescopic sleeve remains sealed after adjustment. The airtight frame, combined with the use of two sets of sealing covers, ensures that when the telescopic sleeve moves to one side or the other, the two sets of sealing rings and U-shaped grooves align with each other, keeping the filter sleeve and telescopic sleeve sealed and preventing heat loss. Attached Figure Description

[0016] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is an overall structural diagram of the flow equalization disk in this invention; Figure 3 This is an overall structural diagram of the tray in this invention; Figure 4 This is an overall structural diagram of the filter sleeve in this invention; Figure 5 This is a diagram of the internal structure of the telescopic sleeve in this invention.

[0018] In the diagram: 1. Sintering furnace; 2. Fan; 3. First flue; 4. Second flue; 5. Filter sleeve; 6. Drying box; 7. Tray; 8. Valve; 9. Flow equalization plate; 10. Divider plate; 11. Mesh plate; 12. Exhaust nozzle; 13. Sliding frame; 14. Slide groove; 15. Horizontal push rod; 16. Telescopic sleeve; 17. Filter; 18. U-shaped groove; 19. Airtight frame; 20. Sealing cover; 21. Sealing ring. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0020] like Figures 1-5As shown, a waste heat recovery device for ferrite magnetic ring sintering includes a fan 2, a first flue 3, and a second flue 4. The fan 2 is fixedly installed at the upper middle position of the sintering furnace 1. The first flue 3 is fixedly installed on one side of the outer surface of the fan 2, and the second flue 4 is fixedly installed on the other side of the outer surface of the fan 2. A filter sleeve 5 is fixedly sleeved on the outer surface of the second flue 4. A drying box 6 is connected through the exhaust end of the second flue 4. Several sets of trays 7 are installed inside the drying box 6. A telescopic sleeve 16 is movably installed inside the filter sleeve 5. The exhaust end of the first flue 3 is connected through the sintering furnace 1.

[0021] Both the exhaust ends of the first flue 3 and the second flue 4 are equipped with valves 8. An exhaust nozzle 12 is provided on one side of the second flue 4. During operation, the waste heat generated during the operation of the sintering furnace 1 can be transferred back to the interior of the sintering furnace 1 to heat the ferrite magnetic rings inside the sintering furnace 1. The first flue 3 draws hot air of 300 to 600 degrees Celsius from the sintering furnace 1 and delivers it to the heating zone of the sintering furnace 1, which is the preheating section. The hot air is then reintroduced into the kiln through evenly distributed air jets. The waste heat is used to perform gradient preheating and degreasing of the ferrite magnetic ring green billets. This not only significantly reduces the consumption of gas or electricity in the main heating section, but also avoids cracking of the green billets through precise temperature control, realizing closed-loop utilization of heat circulation in the kiln and improving energy efficiency.

[0022] The valve 8 and the exhaust nozzle 12 are connected in a continuous manner. A flow equalization plate 9 is fixedly installed on the outer surface of one end of the exhaust nozzle 12. Several sets of partition plates 10 are fixedly installed on the inner side of the flow equalization plate 9. During operation, the blower 2 is used to extract the excess heat in the sintering furnace 1, and a part of the hot air is transported to the interior of the drying box 6 through the second flue 4. In the ferrite magnetic ring processing stage, the ferrite magnetic ring blank can be dried and dehydrated. The setting of the flow equalization plate 9 can evenly discharge the hot air discharged into the exhaust nozzle 12 upward. The exhaust nozzle 12 and the flow equalization plate 9 are connected by air passages corresponding to the number of partition plates 10, so that the hot air discharged from the exhaust nozzle 12 is guided to each set of partition plates 10. The hot air is evenly discharged upward through the flow equalization plate 9 to dry and dehydrate the ferrite magnetic ring blank in the tray 7.

[0023] A mesh plate 11 is fixedly installed on the upper outer surface of the flow equalization plate 9. The flow equalization plate 9 is fixedly installed at the lower end of the inside of the drying oven 6. The mesh plate 11 is used to disperse the hot air a second time to avoid heat accumulation. The flow equalization plate 9 is set at the bottom position. The hot air is discharged upward through the flow equalization plate 9, which can evenly dry the ferrite magnetic ring blanks in several sets of trays 7.

[0024] The bottom of the tray 7 is open, and several sets of sliding frames 13 are movably installed on the inner side of the tray 7. The two ends of the sliding frames 13 are slidably connected to the tray 7 through the sliding grooves 14. The sliding grooves 14 are located on the inner side of the tray 7. During operation, the ferrite magnetic ring blank to be dried is placed on the upper end of the sliding frame 13, and then the sliding frame 13 is moved along the sliding grooves 14 of the tray 7 by sliding the sliding frame 13, so that the two sets of sliding frames 13 have a certain distance, and the upper and lower layers of sliding frames 13 are staggered. This allows the hot air discharged from the equalizing plate 9 to pass through the sliding frames 13 of the several sets of tray 7, so that the ferrite magnetic ring blank and the hot air can fully contact each other, and the lower tray 7 is prevented from blocking the heat transfer.

[0025] Both outer surfaces of the filter sleeve 5 are provided with transverse push rods 15. The filter sleeve 5 and the telescopic sleeve 16 are driven by the transverse push rods 15. During operation, the filter sleeve 5 can filter impurities in the air when hot air passes through the filter 17. The transverse push rods 15 drive the telescopic sleeve 16 to move, so that the filter sleeve 5 can have the function of switching the filter 17.

[0026] Two sets of filters 17 are spliced ​​and installed on the inner side of the telescopic sleeve 16. Sealing caps 20 are fixedly installed on the outer surfaces of both ends of the telescopic sleeve 16. Users can directly insert the filters 17 into the slots of the telescopic sleeve 16 to replace the filters 17. The sealing caps 20 can improve the sealing performance of the telescopic sleeve 16 after it is moved and adjusted.

[0027] An airtight frame 19 is fixedly installed at the middle of the outer surface of the telescopic sleeve 16. Two sets of filters 17 are located on both sides of the airtight frame 19. When the telescopic sleeve 16 is moved and switched, the airtight frame 19 can be sealed and connected to the inner sides of both ends of the filter sleeve 5 to prevent hot air from leaking out from the gap between the filter sleeve 5 and the telescopic sleeve 16 when passing through the filter sleeve 5.

[0028] Sealing rings 21 are provided on one outer surface of the sealing cover 20 and on both outer surfaces of the airtight frame 19. The inner and outer surfaces of both sides of the filter sleeve 5 are provided with U-shaped grooves 18 that cooperate with the sealing rings 21. When the filter 17 is switched, the horizontal push rod 15 is an electric push rod. The horizontal push rod 15 drives the telescopic sleeve 16 to move to one side, removing the used filter 17 from the inside of the filter sleeve 5. At the same time, the replacement filter 17 is moved into the inside of the filter sleeve 5. At this time, the sealing ring 21 on one side of the sealing cover 20 aligns with the U-shaped groove 18 on the outside of the filter sleeve 5, while the sealing ring 21 at the corresponding position of the airtight frame 19 aligns with the U-shaped groove 18 on the inside of the filter sleeve 5. This ensures that the telescopic sleeve 16 remains sealed after movement and adjustment. At the same time, the setting of the airtight frame 19, in conjunction with the use of the two sets of sealing covers 20, allows the two sets of sealing rings 21 and U-shaped grooves 18 to align with each other when the telescopic sleeve 16 moves to one side or the other side.

[0029] The sealing ring 21 has an overall U-shaped structure, and the sealing ring 21 and the U-shaped groove 18 fit together.

[0030] A waste heat recovery device for ferrite magnetic ring sintering, in use, utilizes a fan 2 to extract excess heat from the sintering furnace 1, and transports a portion of the hot air to the interior of the drying chamber 6 through a second flue 4. During the ferrite magnetic ring processing, the ferrite magnetic ring blank can be dried and dehydrated. The uniform flow plate 9 ensures that the hot air discharged from the exhaust nozzle 12 is evenly discharged upwards. The exhaust nozzle 12 and the uniform flow plate 9 are connected by air passages corresponding to the number of partition plates 10, guiding the hot air discharged from the exhaust nozzle 12 to each set of partition plates 10. The uniform flow plate 9 then evenly discharges the hot air upwards, and the mesh plate 11 further disperses the hot air to prevent heat accumulation. The ferrite ring blank to be dried is placed on the upper end of the sliding frame 13. The sliding frame 13 moves along the groove 14 of the tray 7, so that the two sets of sliding frames 13 have a certain distance, so that hot air can pass through the gap between the two sets of sliding frames 13 and move upward. At the same time, the upper and lower layers of sliding frames 13 are staggered, so that the hot air discharged from the equalizing plate 9 can pass through the gaps between the sliding frames 13 of several sets of trays 7, so that the ferrite ring blank and the hot air can make full contact, avoid the lower tray 7 from blocking the heat transfer, and dry and dehydrate the ferrite ring blank in the tray 7, so that the heating of the multi-layer ferrite ring blank is more uniform.

[0031] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A waste heat recovery device for ferrite magnetic ring sintering, characterized in that, The system includes a fan (2), a first flue (3), and a second flue (4). The fan (2) is fixedly installed at the upper middle position of the sintering furnace (1). The first flue (3) is fixedly installed on one side of the outer surface of the fan (2). The second flue (4) is fixedly installed on the other side of the outer surface of the fan (2). A filter sleeve (5) is fixedly fitted on the outer surface of the second flue (4). A drying box (6) is connected through the outlet of the second flue (4). Several sets of trays (7) are installed on the inner side of the drying box (6). A telescopic sleeve (16) is movably installed on the inner side of the filter sleeve (5).

2. The waste heat recovery device for ferrite magnetic ring sintering according to claim 1, characterized in that, The exhaust ends of the first flue (3) and the second flue (4) are both equipped with valves (8), and an exhaust nozzle (12) is provided on one side of the second flue (4).

3. The waste heat recovery device for ferrite magnetic ring sintering according to claim 2, characterized in that, The valve (8) and the exhaust nozzle (12) are connected in a continuous manner. A flow equalization plate (9) is fixedly installed on the outer surface of one end of the exhaust nozzle (12), and several sets of partition plates (10) are fixedly installed on the inner side of the flow equalization plate (9).

4. The waste heat recovery device for ferrite magnetic ring sintering according to claim 3, characterized in that, A mesh plate (11) is fixedly installed on the upper outer surface of the flow equalization plate (9), and the flow equalization plate (9) is fixedly installed at the lower end of the interior of the drying oven (6).

5. The waste heat recovery device for ferrite magnetic ring sintering according to claim 1, characterized in that, The bottom of the tray (7) is open, and several sets of sliding frames (13) are movably installed on the inner side of the tray (7). The two ends of the sliding frames (13) are slidably connected to the tray (7) through the sliding grooves (14), which are located on the inner side of the tray (7).

6. The waste heat recovery device for ferrite magnetic ring sintering according to claim 1, characterized in that, The filter sleeve (5) is provided with transverse push rods (15) on both outer surfaces, and the filter sleeve (5) and the telescopic sleeve (16) are driven by the transverse push rods (15).

7. The waste heat recovery device for ferrite magnetic ring sintering according to claim 6, characterized in that, Two sets of filters (17) are spliced ​​and installed on the inner side of the telescopic sleeve (16), and sealing caps (20) are fixedly installed on the outer surfaces of both ends of the telescopic sleeve (16).

8. The waste heat recovery device for ferrite magnetic ring sintering according to claim 7, characterized in that, An airtight frame (19) is fixedly installed at the middle of the outer surface of the telescopic sleeve (16), and two sets of filters (17) are located on both sides of the airtight frame (19).

9. The waste heat recovery device for ferrite magnetic ring sintering according to claim 8, characterized in that, The sealing cover (20) has a sealing ring (21) on one side of its outer surface and the airtight frame (19) has sealing rings (21) on both sides of its outer surface. The filter sleeve (5) has a spiral groove (18) on both sides of its inner and outer surfaces that works with the sealing ring (21).

10. A waste heat recovery device for ferrite magnetic ring sintering according to claim 9, characterized in that, The sealing ring (21) has a U-shaped structure, and the sealing ring (21) and the U-shaped groove (18) fit together.

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