Energy-saving industrial waste gas purification device

Abstract

The invention discloses an energy-saving industrial waste gas purification device which comprises a purification tank, the interior of the purification tank is sequentially divided into a primary filter cavity, a pressurization cavity, a secondary filter cavity, a heat exchange cavity and a purification cavity, a primary filter mechanism is fixedly arranged in the primary filter cavity, a gas distribution plate is arranged between the primary filter cavity and the pressurization cavity, a baffle and a secondary filter mechanism are arranged in the secondary filter cavity, and a heat exchanger is arranged in the heat exchange cavity. A water storage tank is arranged at the top of the heat exchange cavity, a plurality of spraying heads are arranged at the top of the secondary filter cavity, the water storage tank is connected with the spraying heads through water pipes, ball valves are arranged on the water pipes, and a transmission mechanism is further arranged in the secondary filter cavity. The transmission mechanism opens the ball valve, the spray header sprays hot water, impurities on the secondary filtering mechanism can be flushed, the secondary filtering mechanism can be wetted, and the impurity filtering effect of the secondary filtering mechanism is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of industrial waste gas purification, and in particular to an energy-saving industrial waste gas purification device. Background Art

[0002] In the process of industrial production, a large amount of waste gas and substances harmful to the human body such as carbon monoxide, sulfur dioxide, hydrocarbons, etc. will be generated. Waste gas purification mainly refers to the work of treating industrial waste gas generated in industrial sites. A large amount of industrial waste gas discharged into the atmosphere will inevitably reduce the quality of the air environment, cause damage to human health, and cause huge losses to the national economy. After the harmful substances in industrial waste gas enter the human body through the respiratory tract and skin, they can cause temporary and permanent lesions in the respiratory, blood, liver and other systems and organs.

[0003] Industrial waste gas often contains a high amount of heat, which is generally recovered to achieve the purpose of energy saving and environmental protection. However, since industrial waste gas contains a lot of particulate matter, it needs to be filtered before heat recovery, but some heat will be lost during the filtration process. How to reduce heat loss is the direction of research and development at this stage. In response to the above problems, a solution is proposed below. Summary of the invention

[0004] The object of the present invention is to provide an energy-saving industrial waste gas purification device having the advantages of being able to.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: An energy-saving industrial waste gas purification device comprises a purification tank, which is divided into a primary filter chamber, a boost chamber, a secondary filter chamber, a heat exchange chamber and a purification chamber in sequence. One end of the primary filter chamber is communicated with the outside through an air inlet pipe. A primary filter mechanism is fixed in the primary filter chamber. An air distribution plate is arranged between the primary filter chamber and the boost chamber. A plurality of air distribution pipes are arranged on the air distribution plate. The primary filter chamber and the boost chamber are communicated through the air distribution pipe. A boost pad is arranged in the boost chamber, and the boost pad is elastic. The boost chamber and the secondary filter chamber are separated by a partition, and a ventilation pipe is connected to the partition. An automatic valve is connected to the ventilation pipe. A baffle and a secondary filter mechanism are arranged in the secondary filter chamber. The baffle is arranged at an angle, and the lower end of the baffle is hinged to the secondary filter chamber, and the upper end of the baffle is hinged to the secondary filter chamber. The lower side of the filter mechanism is connected, the secondary filter mechanism is made of soft material, the upper side of the secondary filter mechanism is fixedly connected to the top of the secondary filter chamber, a heat exchanger is arranged in the heat exchange chamber, the outlet of the secondary filter chamber is connected to the air inlet of the heat exchanger through a pipeline, the water inlet of the heat exchanger is connected to an external water source, a water storage tank is arranged on the top of the heat exchange chamber, the water storage tank is used to store hot water, a plurality of spray heads are arranged on the top of the secondary filter chamber, the water storage tank is connected to the spray head through a water pipe, a ball valve is arranged on the water pipe, a transmission mechanism is also arranged in the secondary filter chamber, the input end of the transmission mechanism is connected to the baffle, the transmission mechanism is used to drive the ball valve to rotate to change the unblocking state of the ball valve, the air outlet of the heat exchanger is connected to the purification chamber, and the purification chamber is used to purify gas.

[0006] Preferably, the primary filter mechanism includes two filter plates and a primary filter element filled between the two filter plates, the two filter plates are made of rigid material, the two filter plates are snap-connected, and the two connected filter plates form a filter box, the primary filter element is folded in a V-shape, and the primary filter element and the two filter plates are detachably connected.

[0007] Preferably, several of the air distribution pipes are arranged around the air distribution plate, and one end of several of the air distribution pipes extends into the boosting chamber. One end of the air distribution pipe located in the boosting chamber is inclined and all face the position of the central axis of the purification tank. One-way valves are provided on several of the air distribution pipes.

[0008] Preferably, a vibrating ball is provided in the boost chamber, the vibrating ball is hemispherical and located at the center of the boost chamber, the curved surface of the vibrating ball faces the air distribution plate, and the air outlets of several air distribution pipes are all facing the vibrating ball. Several tension springs are provided in the boost chamber, and several tension springs are arranged around the vibrating ball, one end of the tension spring is connected to the vibrating ball, and the other end of the tension spring is connected to the side wall of the boost chamber, and the number of the tension springs is not less than four.

[0009] Preferably, the secondary filter mechanism comprises a non-woven fabric filter, a glass fiber filter and a nano silver filter, the three layers of filters are arranged in sequence, and the non-woven fabric filter is located on the side close to the partition.

[0010] Preferably, the transmission mechanism includes a driving shaft and a driven shaft, a transmission chamber is separated in the secondary filter chamber, one end of the driving shaft passes through the side wall of the transmission chamber and is located in the transmission chamber, the driving shaft is rotatably connected to the side wall of the transmission chamber, the end of the driving shaft located in the secondary filter chamber is connected to a main gear, an arc-shaped tooth plate is fixedly provided on one side of the baffle, the main gear is meshed with the tooth plate, a bevel gear is fixedly provided at one end of the driving shaft located in the transmission chamber, the driven shaft is longitudinally arranged, the lower end of the driven shaft is located in the transmission chamber, and a bevel gear is also provided at the lower end of the driven shaft, the two bevel gears are meshed with each other, the upper end of the driven shaft passes through the top of the transmission chamber and is rotatably connected to the transmission chamber, the upper end of the driven shaft is fixedly connected to the ball valve, and the upper end of the driven shaft is used to drive the ball valve to rotate to change the clear or blocked state of the ball valve.

[0011] Preferably, a dosing tank is provided at the upper end of the purification chamber, the hot water tank is connected to the dosing tank through a pipeline, a spray head is provided at the top of the purification chamber, the dosing tank is connected to the spray head in the purification chamber through a pipeline, one side of the purification chamber is connected to the outside through an air outlet pipe, a plurality of purification layers are provided in the purification chamber, the plurality of purification layers are sequentially arranged in the purification chamber along the height direction, and the positions of the plurality of purification layers are all lower than the height of the air outlet pipe.

[0012] The beneficial effects of the present invention are as follows: when the exhaust gas enters the boost chamber after the primary filtration, it will hit the hemisphere, accelerating the collision between the fine particles, making them more chaotic and disordered. When the boost chamber reaches the set pressure value, it will be sprayed into the secondary filter chamber; Due to the pressure difference, the gas flow rate from the boost chamber to the secondary filter chamber will be greater, which can blow the baffle to rotate around the hinge, and open the ball valve through the transmission mechanism. At this time, the spray head in the secondary filter chamber will spray hot water, which can not only clean and moisten the secondary filter mechanism, but also keep the secondary filter chamber at a certain temperature to prevent the heat in the exhaust gas from escaping; the water remaining in the secondary filter chamber can be discharged through the pipeline and processed centrally; After two filtrations, most of the particulate matter impurities in the exhaust gas are removed and will no longer cause damage to the subsequent heat exchanger. The heat exchanger can be used to heat external cold water for cleaning the secondary filter mechanism or for other purposes; The final cold exhaust gas is neutralized and purified by spraying chemicals in the purification chamber, and then discharged or connected to other processing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of an embodiment; Figure 2 is a cross-sectional view of an embodiment; Figure 3 It is a cross-sectional view of an embodiment for showing a transmission mechanism; Figure 4 It is a schematic diagram of the structure of the embodiment used to demonstrate the primary filtration mechanism.

[0014] Figure numerals: 1. purification tank; 2. primary filter chamber; 3. boost chamber; 4. secondary filter chamber; 5. heat exchange chamber; 6. purification chamber; 7. primary filter mechanism; 8. air distributor plate; 9. air distributor pipe; 10. boost pad; 11. partition; 12. vent pipe; 13. automatic valve; 14. baffle; 15. secondary filter mechanism; 16. heat exchanger; 17. water storage tank; 18. ball valve; 19. filter plate; 20. primary filter element; 21. one-way valve; 22. vibration ball; 23. tension spring; 24. driving shaft; 25. driven shaft; 26. main gear; 27. tooth plate; 28. bevel gear; 29. ​​dosing tank; 30. spray head; 31. purification layer. DETAILED DESCRIPTION

[0015] The following is only a preferred embodiment of the present invention, and the protection scope is not limited to this embodiment. All technical solutions under the concept of the present invention should belong to the protection scope of the present invention. The same parts are represented by the same figure marks. It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings, and the words "bottom" and "top", "inside" and "outside" refer to the directions toward or away from the geometric center of a specific component, respectively.

[0016] like Figures 1 to 4 As shown, an energy-saving industrial waste gas purification device includes a purification tank 1, which is divided into a primary filter chamber 2, a booster chamber 3, a secondary filter chamber 4, a heat exchange chamber 5 and a purification chamber 6 in sequence.

[0017] One end of the primary filter chamber 2 is connected to the outside through an air inlet pipe, and the external industrial waste gas enters the primary filter chamber 2 through the air inlet pipe. A primary filter mechanism 7 is fixed in the primary filter chamber 2, and the primary filter mechanism 7 can perform preliminary filtration on the industrial waste gas. In the present application, the primary filter mechanism 7 includes two filter plates 19 and a primary filter element 20. The two filter plates 19 can be buckled together through a snap-fit ​​structure. After buckling, the two filter plates 19 will form a filter box, and the primary filter element 20 is filled in the filter box.

[0018] In this design, the primary filter element 20 is folded into a V shape to increase its contact area. The two filter plates 19 are made of rigid materials, such as metal or ceramic, which are corrosion-resistant and high-temperature-resistant materials. The primary filter element 20 is a filter element made of high-temperature-resistant materials such as commonly used stainless steel woven mesh and stainless steel fiber sintered felt. The primary filter mechanism 7 mainly removes some larger particles in the exhaust gas, and the primary filter element 20 is detachably connected to the two filter plates 19, so it can be taken out for cleaning.

[0019] An air distribution plate 8 is provided between the primary filter chamber 2 and the boost chamber 3, and a plurality of air distribution pipes 9 are provided on the air distribution plate 8, and the plurality of air distribution pipes 9 are arranged around the air distribution plate 8. One end of the plurality of air distribution pipes 9 extends into the boost chamber 3, and the end of the air distribution pipes 9 located in the boost chamber 3 is inclined, and the inclination direction of the plurality of air distribution pipes 9 is toward the center line of the purification tank 1, and is inclined toward the side away from the air distribution plate 8. A one-way valve 21 is provided on each air distribution pipe 9, so that the exhaust gas can flow from the primary filter chamber 2 to the boost chamber 3, and cannot flow back from the boost chamber 3 to the primary filter chamber 2.

[0020] A vibrating ball 22 is provided in the boost chamber 3. The vibrating ball 22 is hemispherical and located at the center of the boost chamber 3. The arc surface of the vibrating ball 22 faces the air distribution plate 8. The exhaust gas blown out from the several air distribution pipes 9 will be blown onto the arc surface of the vibrating ball 22. The particulate impurities in the exhaust gas will be dispersed due to hitting the vibrating ball 22, making the particulate impurities more disordered and easier to filter. A plurality of tension springs 23 are provided in the boost chamber 3. The plurality of tension springs 23 are arranged around the vibrating ball 22. One end of the tension spring 23 is connected to the vibrating ball 22, and the other end of the tension spring 23 is connected to the side wall of the boost chamber 3. The number of tension springs 23 is not less than four. The tension spring 23 fixes the vibrating ball 22 in a fixed area, so that the vibrating ball 22 can shake within a certain range, which is more conducive to the dispersion of particulate impurities.

[0021] A boost pad 10 is provided in the boost chamber 3. The boost pad 10 is elastic and made of elastic materials such as rubber. Gas is injected into the boost chamber 3 through a plurality of gas distribution pipes 9. The gas power at the gas distribution pipes 9 is provided by a high-temperature fan connected to the outside of the purification tank 1. When the air pressure in the boost chamber 3 gradually increases, the boost pad 10 will swell, generating elastic potential energy, so that the boost chamber 3 can reach a higher air pressure value.

[0022] The boost chamber 3 is separated from the secondary filter chamber 4 by a partition 11, and a vent pipe 12 is connected to the partition 11, and an automatic valve 13 is connected to the vent pipe 12. The automatic valve 13 in this design is a valve that can be automatically opened when the air pressure value in the boost chamber 3 reaches a set value, such as a safety valve in the prior art, or a solenoid valve with an air pressure sensor. When the air pressure value in the boost chamber 3 reaches a set value, the automatic valve 13 opens, allowing the exhaust gas in the boost chamber 3 to enter the secondary filter chamber 4 through the vent pipe 12.

[0023] A baffle 14 and a secondary filter mechanism 15 are provided in the secondary filter chamber 4. The secondary filter mechanism 15 includes a non-woven fabric filter, a glass fiber filter and a nano silver filter arranged in sequence. This design uses these three filters to filter the exhaust gas. Other filters of different materials but capable of withstanding water washing may also be used.

[0024] The baffle 14 is arranged at an angle, and the lower end of the baffle 14 is hingedly connected to the secondary filter chamber 4, and the upper end of the baffle 14 is connected to the lower side of the secondary filter mechanism 15. The interior of the secondary filter chamber 4 is a square space, and the two sides of the baffle 14 are against the side walls of the secondary filter chamber 4, and the vent pipe 12 is located above the hinge of the baffle 14. Therefore, the wind blown out of the vent pipe 12 will move the baffle 14 obliquely upward and pass through the secondary filter mechanism 15 while blowing the baffle 14.

[0025] The gas filtered for the second time by the secondary filtering mechanism 15 will enter the heat exchanger 16 in the heat exchange chamber 5. The heat exchanger 16 is a prior art. The outlet of the secondary filtering chamber 4 is connected to the air inlet of the heat exchanger 16 through a pipeline. The water inlet of the heat exchanger 16 is connected to an external water source. A water storage tank 17 is provided on the top of the heat exchange chamber 5. The water passing through the heat exchanger 16 will become hot water and enter the water storage tank 17 for storage.

[0026] A transmission mechanism is also provided in the secondary filter chamber 4, and the transmission mechanism includes a driving shaft 24 and a driven shaft 25. A transmission chamber is separated in the secondary filter chamber 4, and one end of the driving shaft 24 passes through the side wall of the transmission chamber and is located in the transmission chamber; the driven shaft 25 is arranged longitudinally, and its lower end is located in the transmission chamber, and the upper end passes through the top of the transmission chamber and is located outside the purification tank 1. An arc-shaped tooth plate 27 is fixedly provided on one side of the baffle 14, and the end of the driving shaft 24 located in the secondary filter chamber 4 is connected to a main gear 26, and the main gear 26 is meshed with the tooth plate 27. A bevel gear 28 is provided at one end of the driving shaft 24 and the driven shaft 25 located in the transmission chamber, and the two bevel gears 28 are meshed. A plurality of spray heads 30 are provided on the top of the secondary filter chamber 4, and the water storage tank 17 is connected to the spray head 30 through a water pipe. A ball valve 18 is provided on the water pipe, and the upper end of the driven shaft 25 is connected to the ball valve 18.

[0027] When the boost chamber 3 blows air into the secondary filter chamber 4, the baffle 14 will be blown to one side, so that the tooth plate 27 drives the main gear 26 to rotate. The main gear 26 drives the driven shaft 25 to rotate through the driving shaft 24 and the two meshing bevel gears 28, so that the driven shaft 25 can open the ball valve 18, and the hot water in the water pipe will be sprayed onto the secondary filter mechanism 15 through the spray head 30 in the secondary filter chamber 4, which can not only wet the secondary filter mechanism 15 and enhance its ability to filter and adsorb particles, but also wash off the particles originally adsorbed on the surface of the secondary filter mechanism 15, so that the secondary filter mechanism 15 can be kept clean; it can also maintain the temperature in the secondary filter chamber 4 and reduce the heat dissipation in the exhaust gas. When the boost chamber 3 stops blowing air into the secondary filter chamber 4, the baffle 14 will be reset under the action of the torsion spring at the hinge, so that the ball valve 18 is closed, and the spray head 30 located in the secondary filter chamber 4 will no longer spray hot water.

[0028] The air outlet of the heat exchanger 16 is connected to the purification chamber 6, and a plurality of purification layers 31 are arranged in the purification chamber 6 in sequence along the height direction, and the positions of the plurality of purification layers 31 are all lower than the height of the air outlet pipe. The air outlet is located below the plurality of purification layers 31, and the gas entering the purification chamber 6 from the air outlet will pass upward through the plurality of purification layers 31, remove some harmful substances in the gas, and then be discharged through the air outlet pipe. The purification layer 31 in the present application is made of a water-absorbent material such as cotton.

[0029] A dosing tank 29 is provided at the upper end of the purification chamber 6, and the hot water tank is connected to the dosing tank 29 through a pipeline. A spray head 30 is provided at the top of the purification chamber 6, and the dosing tank 29 is connected to the spray head 30 in the purification chamber 6 through a pipeline. A solenoid valve can be set on the pipeline between the dosing tank 29 and the spray head 30 for control. The agent in the dosing tank 29 is prepared according to the substances in the exhaust gas, and the hot water in the hot water tank can be used for preparation to accelerate the dissolution of the agent. After the preparation is completed, the agent is sprayed through the spray head 30 in the purification tank 1, and several purification layers 31 are moistened, so that the gas can fully react when passing through the purification layer 31 to remove harmful substances in the gas.

[0030] The water in the purification chamber 6 and the secondary filter chamber 4 can be discharged through the pipes arranged thereon, and the pipes can be sealed and opened only for drainage.

[0031] The specific embodiments described above further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An energy-saving industrial waste gas purification device, comprising a purification tank (1), characterized in that: The purification tank (1) is divided into a primary filter chamber (2), a boost chamber (3), a secondary filter chamber (4), a heat exchange chamber (5) and a purification chamber (6) in sequence. One end of the primary filter chamber (2) is connected to the outside through an air inlet pipe. A primary filter mechanism (7) is fixedly arranged in the primary filter chamber (2). An air distribution plate (8) is arranged between the primary filter chamber (2) and the boost chamber (3). A plurality of air distribution pipes (9) are arranged on the air distribution plate (8). The primary filter chamber (2) and the boost chamber (3) are connected through the air distribution pipes (9). A boost pad (10) is arranged in the cavity (3), and the boost pad (10) is elastic. The boost cavity (3) and the secondary filter cavity (4) are separated by a partition (11), and a vent pipe (12) is connected to the partition (11), and an automatic valve (13) is connected to the vent pipe (12). A baffle (14) and a secondary filter mechanism (15) are arranged in the secondary filter cavity (4), and the baffle (14) is arranged in an inclined manner, and the lower end of the baffle (14) is hingedly connected to the secondary filter cavity (4), and the upper end of the baffle (14) is hingedly connected to the secondary filter cavity (4). The end is connected to the lower side of the secondary filter mechanism (15), the secondary filter mechanism (15) is made of soft material, the upper side of the secondary filter mechanism (15) is fixedly connected to the top of the secondary filter chamber (4), a heat exchanger (16) is arranged in the heat exchange chamber (5), the outlet of the secondary filter chamber (4) is connected to the air inlet of the heat exchanger (16) through a pipeline, the water inlet of the heat exchanger (16) is connected to an external water source, and a water storage tank (17) is arranged on the top of the heat exchange chamber (5), the water storage tank (17) is used to store hot water, A plurality of spray heads (30) are provided on the top of the secondary filter chamber (4); the water storage tank (17) is connected to the spray heads (30) via a water pipe; a ball valve (18) is provided on the water pipe; a transmission mechanism is also provided in the secondary filter chamber (4); an input end of the transmission mechanism is connected to a baffle (14); the transmission mechanism is used to drive the ball valve (18) to rotate so as to change the unblocking state of the ball valve (18); an outlet of the heat exchanger (16) is connected to a purification chamber (6); and the purification chamber (6) is used to purify gas.

2. The energy-saving industrial waste gas purification device according to claim 1 is characterized in that: The primary filter mechanism (7) comprises two filter plates (19) and a primary filter element (20) filled between the two filter plates (19); the two filter plates (19) are made of a rigid material, the two filter plates (19) are snap-connected, and the two connected filter plates (19) form a filter box; the primary filter element (20) is folded in a V-shape, and the primary filter element (20) and the two filter plates (19) are detachably connected.

3. The energy-saving industrial waste gas purification device according to claim 1 is characterized in that: A plurality of the gas distribution pipes (9) are arranged around the gas distribution plate (8), and one end of the plurality of the gas distribution pipes (9) extends into the boost chamber (3). One end of the gas distribution pipes (9) located in the boost chamber (3) is arranged at an angle and faces the position of the central axis of the purification tank (1). A one-way valve (21) is arranged on each of the plurality of gas distribution pipes (9).

4. The energy-saving industrial waste gas purification device according to claim 3 is characterized in that: A vibrating ball (22) is arranged in the boost chamber (3). The vibrating ball (22) is hemispherical and located at the center of the boost chamber (3). The arc surface of the vibrating ball (22) faces the air distribution plate (8), and the air outlets of the plurality of air distribution pipes (9) all face the vibrating ball (22). A plurality of tension springs (23) are arranged in the boost chamber (3). The plurality of tension springs (23) are arranged around the vibrating ball (22), one end of the tension spring (23) is connected to the vibrating ball (22), and the other end of the tension spring (23) is connected to the side wall of the boost chamber (3). The number of the tension springs (23) is not less than four.

5. The energy-saving industrial waste gas purification device according to claim 1 is characterized in that: The secondary filter mechanism (15) comprises a non-woven fabric filter, a glass fiber filter and a nano silver filter, the three layers of filters are arranged in sequence, and the non-woven fabric filter is located on a side close to the partition (11).

6. The energy-saving industrial waste gas purification device according to claim 1 is characterized in that: The transmission mechanism comprises a driving shaft (24) and a driven shaft (25); a transmission chamber is separated in the secondary filter chamber (4); one end of the driving shaft (24) passes through the side wall of the transmission chamber and is located in the transmission chamber; the driving shaft (24) is rotatably connected to the side wall of the transmission chamber; one end of the driving shaft (24) located in the secondary filter chamber (4) is connected to a main gear (26); an arc-shaped tooth plate (27) is fixedly provided on one side of the baffle (14); the main gear (26) meshes with the tooth plate (27); the driving shaft (24) is located in the transmission chamber A bevel gear (28) is fixedly arranged at one end, the driven shaft (25) is arranged longitudinally, the lower end of the driven shaft (25) is located in the transmission cavity, and the lower end of the driven shaft (25) is also provided with a bevel gear (28), the two bevel gears (28) are meshed with each other, the upper end of the driven shaft (25) passes through the top of the transmission cavity, and is rotatably connected to the transmission cavity, the upper end of the driven shaft (25) is fixedly connected to the ball valve (18), and the upper end of the driven shaft (25) is used to drive the ball valve (18) to rotate, so as to change the open or closed state of the ball valve (18).

7. The energy-saving industrial waste gas purification device according to claim 1 is characterized in that: A dosing tank (29) is provided at the upper end of the purification chamber (6), the hot water tank is connected to the dosing tank (29) via a pipeline, a spray head (30) is provided at the top of the purification chamber (6), the dosing tank (29) is connected to the spray head (30) in the purification chamber (6) via a pipeline, one side of the purification chamber (6) is connected to the outside via an air outlet pipe, a plurality of purification layers (31) are provided in the purification chamber (6), the plurality of purification layers (31) are sequentially arranged in the purification chamber (6) along a height direction, and the positions of the plurality of purification layers (31) are all lower than the height of the air outlet pipe.

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