Drawable ventilation filtering device

Abstract

The invention discloses a drawable ventilation filtering device, and relates to the technical field of filtering devices, the drawable ventilation filtering device comprises a connecting pipe shell, a containing groove is formed in the connecting pipe shell, and communication ports are formed between the containing groove and the upper and lower outer walls of the connecting pipe shell; the filter plate is clamped in the containing groove, a mounting groove is formed in the filter plate, and multiple stages of filter layers are mounted in the mounting groove; the communication port sealing assembly is used for sealing the communication port when the filter plate is taken out; the filter plate sealing assembly is used for automatically enabling the filter plate and the inner wall of the containing groove to be in a sealed state when the filter plate is installed. According to the invention, the connection pipe shell can be automatically controlled to be closed and the filter plate can be sealed and wrapped according to the disassembly and assembly of the filter plate through the communication port sealing assembly and the filter plate sealing assembly, so that the situation of gas leakage can be avoided under any condition, and the use safety is good; extra facilities and operation are not needed, and use is convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of filtering devices, in particular to a pullable ventilation filtering device. BACKGROUND

[0002] The pullable ventilation filtering device is a device used in a ventilation system, usually used to improve air quality in an area and effectively remove pollutants.

[0003] The patent document with the publication number CN210645592U discloses a pullable ventilation filtering device, which comprises a frame, a panel is arranged at the top end of the frame, a handle is arranged at the top center position of the panel, steel wire mesh assemblies are symmetrically arranged on both sides of the frame, a clamping groove is arranged on the inner side of the frame, a fixed frame is clamped in the clamping groove, an initial efficiency filter cloth is inlaid on the inner side of the fixed frame, and clamping mechanisms are symmetrically arranged at the bottom end of the frame.

[0004] The pullable ventilation filtering device in the above technical solution has the problem of easy gas leakage during use. When conveying gas with high dust concentration or containing harmful substances, leakage will cause serious consequences. There are two cases of gas leakage. On the one hand, when the filtering structure is disassembled, the gas in the pipeline will immediately diffuse outward, causing gas leakage. On the other hand, due to the pullable use, wear will occur after long-term use, and gaps will be generated between the frame and the pipeline due to wear, thereby causing gas leakage during use. SUMMARY

[0005] The present application aims to provide a pullable ventilation filtering device that solves the problem of easy gas leakage during use and the technical problem of causing serious consequences when conveying gas with high dust concentration or containing harmful substances.

[0006] The present application solves the above technical problems by the following technical solutions. The present application comprises: A connecting pipe shell is provided, and a containing groove is formed in the connecting pipe shell. A communication port is formed between the containing groove and the upper and lower outer walls of the connecting pipe shell. A filter plate is clamped in the containing groove. An installation groove is formed in the filter plate, and a multi-stage filter layer is installed in the installation groove. The multi-stage filter layer is located between the two communication ports. The connecting port sealing assembly is used for sealing the connecting port when the filter plate is taken out, and comprises a sealing baffle and a plurality of limiting springs, the sealing baffle is clamped in the accommodating groove and located at one end of the filter plate, a placing groove is formed in the sealing baffle, and the limiting springs are installed between the inner wall of the placing groove and the inner wall of the accommodating groove. The filter plate sealing assembly is used for automatically sealing the filter plate and the inner wall of the accommodating groove when the filter plate is installed.

[0007] Preferably, positioning grooves are formed on both sides of the sealing baffle, and a positioning plate clamped in the positioning grooves is installed on the inner wall of the accommodating groove.

[0008] Preferably, the filter plate sealing assembly comprises a sealing capsule ring and two sets of negative pressure control structures, the negative pressure control structures are used for controlling the expansion of the sealing capsule ring to make the sealing between the filter plate and the accommodating groove good, an inner ring groove is formed on the inner wall of the accommodating groove, the sealing capsule ring is clamped in the inner ring groove and the outer edge of the sealing capsule ring is bonded in the inner ring groove, a negative pressure control cavity is formed in the positioning plate, a communication groove is formed between the negative pressure control cavity and the inner ring groove, a connecting pipe for connecting the negative pressure control cavity and the sealing capsule ring is installed in the communication groove, the negative pressure control structures are arranged in the sealing baffle and the negative pressure control cavity, and the negative pressure control cavity and the connecting pipe are filled with a pressurizing medium.

[0009] Preferably, the negative pressure control structure comprises an installation rod and a sealing sheet, the sealing sheet is clamped in the negative pressure control cavity, and the installation rod is installed between the sealing sheet and the positioning groove and passes through the negative pressure control cavity.

[0010] Preferably, the pressurizing medium is one of air, water and hydraulic oil.

[0011] Preferably, a handle is installed on the outer side of the filter plate, and a fixing assembly for fixing the filter plate in the accommodating groove is arranged on both sides of the handle.

[0012] Preferably, the fixing assembly comprises a fixing clamping block, a control sheet, a control block and a control spring, a control groove is formed in the filter plate and the handle, the control sheet spring control spring is installed in the control groove, key grooves are formed on both sides of the inner wall of the accommodating groove, a through port corresponding to the key grooves is formed between the control groove and the outer wall of the filter plate, the fixing clamping block is installed on the control sheet and one end of the fixing clamping block passes through the through port and is clamped in the key groove, a slot is formed between the control groove and the outer wall of the handle, and the control block is installed on the control sheet and clamped in the slot.

[0013] Preferably, the cross-sectional area of the connecting port increases from inside to outside, and the cross-sectional area of the inner side of the connecting port is smaller than that of the sealing baffle.

[0014] Preferably, the connecting pipe shell is provided with an air inlet pipe and an air outlet pipe at both ends.

[0015] The beneficial effects of the present application compared with the prior art are: The present application can automatically control the closure of the connecting pipe shell and the sealing of the filter plate according to the disassembly and assembly of the filter plate through the communication port sealing assembly and the filter plate sealing assembly, so that gas leakage can be prevented in any case, thereby improving the safety and convenience of use. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The front view structure of the present application is shown in the figure. Figure 2 The connecting pipe shell structure of the present application is shown in the figure. Figure 3 The filter plate structure of the present application is shown in the figure. Figure 4 The connecting pipe shell cross-sectional view of the present application (when the filter plate is disassembled) is shown in the figure. Figure 5 The connecting pipe shell cross-sectional view of the present application (when the filter plate is assembled) is shown in the figure. Figure 6 The present application is shown in the figure. Figure 5 The partial structure view of the present application is shown in the figure.

[0017] The figure numbers represent: 1, connecting pipe shell; 2, filter plate; 3, communication port sealing assembly; 301, sealing baffle; 302, limiting spring; 4, filter plate sealing assembly; 401, sealing capsule ring; 402, negative pressure control structure; 4021, mounting rod; 4022, sealing sheet; 5, accommodating groove; 6, communication port; 7, multi-stage filter layer; 8, positioning groove; 9, positioning plate; 10, inner ring groove; 11, negative pressure control cavity; 12, connecting pipe; 13, pressurizing medium; 14, handle; 15, fixing assembly; 1501, fixing block; 1502, control sheet; 1503, control block; 1504, control spring; 16, key groove; 17, air inlet pipe; 18, air outlet pipe. DETAILED DESCRIPTION

[0018] The above and other technical features and advantages of the present application will be described in more detail below with reference to the accompanying drawings. Example 1

[0019] The present embodiment provides a technical solution: a pullable ventilation and filtration device, as shown in the figure, comprising a connecting pipe shell 1, a filter plate 2, a communication port sealing assembly 3 and a filter plate sealing assembly 4. Figures 1-6

[0020] Specific implementation, as shown in the figure Figure 2 ​As shown, the connecting pipe shell 1 is provided with a containing groove 5, and the containing groove 5 is provided with a communication port 6 between the upper and lower outer walls of the connecting pipe shell 1. The communication port 6 on both sides of the containing groove 5 can facilitate the air inflow and exhaust.

[0021] In a specific implementation, as shown in Figure 3 As shown, the filter plate 2 is clamped in the containing groove 5, and the filter plate 2 is provided with a mounting groove. The mounting groove is provided with a multi-stage filter layer 7. The multi-stage filter layer 7 can be a single or combined support of synthetic fiber filter cotton, non-woven filter cotton, glass fiber filter cotton, activated carbon filter cotton and other materials. The multi-stage filter layer 7 is located between the two communication ports 6. The multi-stage filter layer 7 can filter the passing gas to filter out the dust in the gas.

[0022] In a specific implementation, as shown in Figure 4 As shown, the communication port sealing assembly 3 is used to seal the communication port 6 when the filter plate 2 is taken out. The communication port sealing assembly 3 includes a sealing baffle 301 and a plurality of limiting springs 302. The sealing baffle 301 is clamped in the containing groove 5 and located at one end of the filter plate 2. The sealing baffle 301 is provided with a placing groove. The limiting spring 302 is installed between the inner wall of the placing groove and the inner wall of the containing groove 5. The filter plate 2 is disassembled, the limiting spring 302 is in an extended state, and the sealing baffle 301 is located between the communication ports 6. Therefore, the communication port 6 of the air inlet end can be sealed and closed by the sealing baffle 301, so as to prevent the gas flow.

[0023] Further, the cross-sectional area of the communication port 6 increases from inside to outside. The cross-sectional area of the inner side of the communication port 6 is smaller than that of the sealing baffle 301. Therefore, the sealing baffle 301 can completely block the communication port 6, so as to ensure good sealing and closing effect of the communication port 6 of the air inlet end.

[0024] In the specific implementation, the filter plate sealing assembly 4 is used to automatically seal the filter plate 2 and the inner wall of the accommodating groove 5 when the filter plate 2 is loaded, the sealing baffle 301 is provided with a positioning groove 8 on both sides, the inner wall of the accommodating groove 5 is provided with a positioning plate 9 clamped in the positioning groove 8, the filter plate 2 is taken out of the accommodating groove 5, the filter plate sealing assembly 4 comprises a sealing bag ring 401 and two groups of negative pressure control structures 402, the negative pressure control structure 402 is used to control the expansion of the sealing bag ring 401 to make the filter plate 2 and the accommodating groove 5 have good sealing performance, the inner wall of the accommodating groove 5 is provided with an inner ring groove 10, the sealing bag ring 401 is clamped in the inner ring groove 10 and the outer edge of the sealing bag ring 401 is bonded in the inner ring groove 10, the sealing bag ring 401 is in a non-expanded normal state, the sealing bag ring 401 is completely in the inner ring groove 10 and a gap is left between the inner wall of the sealing bag ring 401 and the inner wall of the accommodating groove 5, the positioning plate 9 is provided with a negative pressure control cavity 11, a communication groove is arranged between the negative pressure control cavity 11 and the inner ring groove 10, a connecting pipe 12 for connecting the negative pressure control cavity 11 and the sealing bag ring 401 is arranged in the communication groove, the negative pressure control structure 402 is arranged in the sealing baffle 301 and the negative pressure control cavity 11, the negative pressure control cavity 11 and the connecting pipe 12 are filled with a pressurizing medium 13, and most of the pressurizing medium 13 is in the negative pressure control cavity 11.

[0025] Further, the negative pressure control structure 402 comprises an installation rod 4021 and a sealing sheet 4022, the sealing sheet 4022 is clamped in the negative pressure control cavity 11, the installation rod 4021 is installed between the sealing sheet 4022 and the positioning groove 8 and penetrates the negative pressure control cavity 11, the length of the installation rod 4021 in the negative pressure control cavity 11 is short, and the negative pressure control cavity 11 is filled with the pressurizing medium 13.

[0026] Further, the pressurizing medium 13 is one of air, water or hydraulic oil, air is used as the pressurizing medium 13 to ensure that the volume of the sealing bag ring 401 is more flexible, and water or hydraulic oil is used as the pressurizing medium 13 to ensure that the volume of the sealing bag ring 401 is accurate.

[0027] In the specific implementation, as shown in Figure 1 The connecting pipe shell 1 is provided with an air inlet pipe 17 and an air outlet pipe 18 at both ends, and air can flow into and out of the connecting pipe shell 1 through the air inlet pipe and the air outlet pipe 18.

[0028] In this embodiment, the multi-stage filter layer 7 inside the filter plate 2 can filter the gas passing through when using the gas inlet of the connecting pipe shell 1. When the filter plate 2 needs to be disassembled for cleaning or replacing the multi-stage filter layer 7, the connecting port sealing component 3 can automatically seal and close the connecting port 6 at the air inlet when the filter plate 2 is removed, thus preventing gas flow and gas leakage, thereby avoiding gas pollution to the external environment. When the filter plate 2 is removed, the sealing baffle 301 can be pushed outward under the elastic force of the limiting spring 302. The sealing baffle 301 moves synchronously with the filter plate 2. When the filter plate 2 is completely removed, the sealing baffle 301 completely blocks the connecting port 6 to prevent gas leakage. At the same time, the removal of the filter plate 2 is more convenient and less labor-intensive under the elastic force of the limiting spring 302. Example 2

[0029] This embodiment provides a technical solution: a pull-out ventilation and filtration device, such as... Figures 1-6 As shown, it includes a connecting pipe shell 1, a filter plate 2, a connecting port sealing assembly 3, and a filter plate sealing assembly 4.

[0030] In specific implementations, such as Figure 2 As shown, a receiving groove 5 is provided inside the connecting tube shell 1, and a communication port 6 is provided between the receiving groove 5 and the upper and lower outer walls of the connecting tube shell 1. The airflow can be conveniently introduced and discharged through the communication ports 6 on both sides of the receiving groove 5.

[0031] In specific implementations, such as Figure 3 As shown, the filter plate 2 is installed in the receiving groove 5. The filter plate 2 has an installation groove, and a multi-stage filter layer 7 is installed in the installation groove. The multi-stage filter layer 7 can be supported individually or in combination by materials such as synthetic fiber filter cotton, non-woven filter cotton, glass fiber filter cotton, and activated carbon filter cotton. The multi-stage filter layer 7 is located between the two connecting ports 6. The gas passing through the multi-stage filter layer 7 can be filtered to remove dust from the gas.

[0032] In specific implementations, such as Figure 4 As shown, the connecting port sealing assembly 3 is used to seal the connecting port 6 when the filter plate 2 is removed. The connecting port sealing assembly 3 includes a sealing baffle 301 and multiple limiting springs 302. The sealing baffle 301 is stuck in the receiving groove 5 and located at one end of the filter plate 2. A placement groove is opened in the sealing baffle 301. The limiting springs 302 are installed between the inner wall of the placement groove and the inner wall of the receiving groove 5. The limiting springs 302 are in a compressed state. The multi-stage filter layer 7 is located between the connecting ports 6. Therefore, when the air flows through the connecting pipe shell 1, it needs to pass through the multi-stage filter layer 7.

[0033] In specific implementations, such as Figure 5As shown, the filter plate sealing assembly 4 is used to automatically seal the filter plate 2 and the inner wall of the accommodating groove 5 when the filter plate 2 is loaded, the sealing baffle 301 is provided with a positioning groove 8 on both sides, the inner wall of the accommodating groove 5 is provided with a positioning plate 9 clamped in the positioning groove 8, the filter plate 2 is arranged in the accommodating groove 5, the filter plate sealing assembly 4 comprises a sealing bag ring 401 and two groups of negative pressure control structures 402, the negative pressure control structure 402 is used to control the expansion of the sealing bag ring 401 to make the sealing between the filter plate 2 and the accommodating groove 5 good, the inner wall of the accommodating groove 5 is provided with an inner ring groove 10, the sealing bag ring 401 is clamped in the inner ring groove 10 and the outer edge of the sealing bag ring 401 is bonded in the inner ring groove 10, the sealing bag ring 401 is in an expanded state and the inner wall of the sealing bag ring 401 tightly wraps the local outer side of the filter plate 2, the positioning plate 9 is provided with a negative pressure control cavity 11, a communication groove is arranged between the negative pressure control cavity 11 and the inner ring groove 10, a connecting pipe 12 for connecting the negative pressure control cavity 11 and the sealing bag ring 401 is arranged in the communication groove, the negative pressure control structure 402 is arranged in the sealing baffle 301 and the negative pressure control cavity 11, the negative pressure control cavity 11 and the connecting pipe 12 are filled with a pressurizing medium 13, and most of the pressurizing medium 13 enters the sealing bag ring 401.

[0034] Further, the negative pressure control structure 402 comprises an installation rod 4021 and a sealing sheet 4022, the sealing sheet 4022 is clamped in the negative pressure control cavity 11, the installation rod 4021 is installed between the sealing sheet 4022 and the positioning groove 8 and penetrates the negative pressure control cavity 11, the length of the installation rod 4021 in the negative pressure control cavity 11 is short, and the sealing sheet 4022 pushes the pressurizing medium 13 in the negative pressure control cavity 11 out.

[0035] Further, the pressurizing medium 13 is one of air, water or hydraulic oil, air is used as the pressurizing medium 13 to ensure that the volume change of the sealing bag ring 401 is more flexible, and water or hydraulic oil is used as the pressurizing medium 13 to ensure that the volume change of the sealing bag ring 401 is accurate.

[0036] In a specific implementation, as shown in Figure 5 and Figure 6As shown, the filter plate 2 is provided with a handle 14 outside, and a fixing assembly 15 is arranged inside both sides of the handle 14 for fixing the filter plate 2 in the accommodating groove 5. The fixing assembly 15 can quickly fix the filter plate 2 in the accommodating groove 5, and includes a fixing clamping block 1501, a control piece 1502, a control block 1503 and a control spring 1504. The filter plate 2 and the handle 14 are provided with control grooves, the control piece 1502 and the control spring 1504 are arranged in the control grooves, both sides of the inner wall of the accommodating groove 5 are provided with key grooves 16, and the control grooves and the outer wall of the filter plate 2 are provided with through openings corresponding to the key grooves 16. The fixing clamping block 1501 is arranged on the control piece 1502 and one end of the fixing clamping block 1501 is clamped in the key groove 16 through the through opening. The fixing clamping block 1501 clamped in the key groove 16 can ensure that the filter plate 2 is fixedly connected with the connecting pipe shell 1. The control grooves and the outer wall of the handle 14 are provided with a slot, and the control block 1503 is arranged on the control piece 1502 and clamped in the slot. At the same time, the fixing assembly 15 can conveniently and quickly disassemble the filter plate 2 and the connecting pipe shell 1. When disassembling, the control blocks 1503 on both sides are pressed at the same time, the control blocks 1503 can push the control piece 1502 to extrude the control spring 1504 and move inward, the fixing clamping block 1501 can move out of the key groove 16, and when the fixing clamping block 1501 is completely moved out of the key groove 16, the filter plate 2 and the connecting pipe shell 1 are not fixedly connected. Therefore, the filter plate 2 can be directly disassembled.

[0037] In a specific implementation, as shown in Figure 1 The connecting pipe shell 1 is provided with an air inlet pipe 17 and an air outlet pipe 18 at both ends. The air inlet pipe and the air outlet pipe 18 can conveniently make the airflow enter the connecting pipe shell 1 and be discharged from the connecting pipe shell 1.

[0038] In the embodiment, when the filter plate 2 is installed into the connecting pipe shell 1, the filter plate sealing assembly 4 can be automatically triggered to locally seal between the filter plate 2 and the inner wall of the accommodating groove 5, so that the case that the sealing between the filter plate 2 and the accommodating groove 5 is reduced due to the friction caused by the installation and removal of the filter plate 2 can be prevented, and the gas leakage during use can be prevented. When the filter plate 2 is installed, the filter plate 2 can push the sealing baffle 301 to extrude the limiting spring 302 and move inward, and the installation rod 4021 and the sealing sheet 4022 can be adapted to move along the negative pressure control cavity 11, so that the pressurizing medium 13 in the negative pressure control cavity 11 can be pushed into the connecting pipe 12 and the sealing capsule ring 401 under the pushing of the sealing sheet 4022. Then the sealing capsule ring 401 can expand and start to wrap the filter plate 2. Then the control blocks 1503 on both sides of the pressing handle 14 are pressed, the control blocks 1503 can push the control sheet 1502 to extrude the control spring 1504 and move inward, and the fixed clamping block 1501 can completely enter the control groove. Continue to push the filter plate 2 into the accommodating groove 5, and release the control block 1503 after the filter plate 2 is completely in place. The fixed clamping block 1501 can be bounced into the key groove 16 under the elastic force of the control spring 1504, so that the filter plate 2 can be fixed, and the sealing capsule ring 401 can tightly wrap the filter plate 2.

[0039] The above is only the preferred embodiment of the present application, which is only illustrative but not limiting. Those skilled in the art understand that many changes, modifications and even equivalents can be made to the present application within the spirit and scope defined by the claims of the present application, and all of them will fall within the protection scope of the present application.

Claims

1. A pull-through ventilation filter device, characterized in that, Include: The connecting pipe shell (1), the accommodating groove (5) is opened in the connecting pipe shell (1), the communicating port (6) is opened between the accommodating groove (5) and the upper and lower outer wall of connecting pipe shell (1); Filter plate (2), the filter plate (2) is clamped in the accommodating groove (5), the installation groove is opened in the filter plate (2), the multistage filter layer (7) is installed in the installation groove, and the multistage filter layer (7) is located between the two side communicating ports (6); The communicating port sealing assembly (3) is used to seal the communicating port (6) when the filter plate (2) is taken out, the communicating port sealing assembly (3) includes a sealing baffle (301) and a plurality of limit springs (302), the sealing baffle (301) is clamped in the accommodating groove (5) and located at one end of the filter plate (2), the sealing baffle (301) is opened in the placing groove, and the limit spring (302) is installed between the inner wall of the placing groove and the inner wall of the accommodating groove (5); The filter plate sealing assembly (4) is used to automatically make the filter plate (2) and the inner wall of the accommodating groove (5) in a sealed state when the filter plate (2) is installed.

2. A filter unit as claimed in claim 1, wherein, The sealing baffle (301) is opened in the positioning groove (8) on both sides, and the positioning plate (9) is installed on the inner wall of the accommodating groove (5) and clamped in the positioning groove (8).

3. A filter unit as claimed in claim 2, wherein the filter unit is arranged to be pulled out of the housing by the user. 5 The filter plate sealing assembly (4) includes a sealing capsule ring (401) and two groups of negative pressure control structures (402), the negative pressure control structure (402) is used to control the expansion of the sealing capsule ring (401) to make the filter plate (2) and the accommodating groove (5) between the sealing property, the inner ring groove (10) is opened on the inner wall of the accommodating groove (5), the sealing capsule ring (401) is clamped in the inner ring groove (10) and the outer edge of the sealing capsule ring (401) is bonded in the inner ring groove (10), the negative pressure control cavity (11) is opened in the positioning plate (9), the communicating groove is opened between the negative pressure control cavity (11) and the inner ring groove (10), the connecting pipe (12) is installed in the communicating groove, the connecting pipe (12) is communicated with the negative pressure control cavity (11) and the sealing capsule ring (401), the negative pressure control structure (402) is arranged in the sealing baffle (301) and the negative pressure control cavity (11), and the negative pressure control cavity (11) and the connecting pipe (12) are filled with pressurizing medium (13).

4. A filter unit as claimed in claim 3, wherein the filter unit is arranged to be pulled out of the housing by the user. The negative pressure control structure (402) includes an installation rod (4021) and a sealing sheet (4022), the sealing sheet (4022) is clamped in the negative pressure control cavity (11), and the installation rod (4021) is installed between the sealing sheet (4022) and the positioning groove (8) and passes through the negative pressure control cavity (11).

5. A filter unit as claimed in claim 3, wherein the filter unit is adapted to be mounted in a housing having a plurality of filter units mounted therein. The pressurizing medium (13) is one of air, water or hydraulic oil.

6. A filter unit as claimed in claim 1, wherein, The handle (14) is installed on the outer side of the filter plate (2), and the fixing assembly (15) for fixing the filter plate (2) in the accommodating groove (5) is arranged on the inner side of the handle (14).

7. A filter unit as claimed in claim 6, wherein the filter unit is adapted to be mounted in a housing having a plurality of filter units mounted therein. Said fixed assembly (15) includes fixed clamping block (1501), control piece (1502), control block (1503) and control spring (1504), the filter plate (2) and handle (14) are internally provided with control groove, the control piece (1502) spring control spring (1504) is installed in control groove, the inner wall of the accommodation groove (5) both sides are provided with keyway (16), the control groove and the outer wall of filter plate (2) are provided with the through opening corresponding with keyway (16), the fixed clamping block (1501) is installed on control piece (1502) and one end of fixed clamping block (1501) is clamped in keyway (16) through the through opening, the control groove and the outer wall of handle (14) are provided with the slot, the control block (1503) is installed on control piece (1502) and control block (1503) is clamped in the slot.

8. A filter unit as claimed in claim 1, wherein, The cross-sectional area of the communication port (6) increases from inside to outside, and the cross-sectional area of the communication port (6) is smaller than that of the sealing baffle (301).

9. A filter unit as claimed in claim 1, wherein, The connecting pipe shell (1) is provided with an air inlet pipe (17) and an air outlet pipe (18) at both ends.

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