CN115523066A

CN115523066A - Mining vehicle air filter assembly and blowback control method thereof

Info

Publication number: CN115523066A
Application number: CN202211176889.XA
Authority: CN
Inventors: 杨晨; 刘鹏; 宁凡坤
Original assignee: China National Heavy Duty Truck Group Jinan Power Co Ltd
Current assignee: China National Heavy Duty Truck Group Jinan Power Co Ltd
Priority date: 2022-09-26
Filing date: 2022-09-26
Publication date: 2022-12-27

Abstract

The invention discloses a mining vehicle air filter assembly and a blowback control method thereof, belonging to the technical field of air filters and comprising a prefilter, a filter blowback system and a dust collection system; the filtering and back-blowing system comprises an air filter and a back-blowing air storage tank; the air filter comprises a filter shell, an air filter element and a safety filter element are arranged in the filter shell, and an annular channel is formed between the air filter element and the safety filter element; the upper side and the lower side of the filter shell are respectively provided with a filter air inlet and a filter dust exhaust port which are connected with the prefilter air outlet, and one end surface of the filter shell is provided with a filter air outlet; the back-blowing air storage tank is communicated with the annular channel through a back-blowing air inlet pipe; the dust collection system comprises a dust removal pump, and an inlet of the dust removal pump is connected with a dust discharge port of the filter. The closed air filter avoids external influence; the integration level is high, and the space occupation is reduced; realize the automatic blowback of air filter, intelligent judgement maintenance opportunity reduces the manual maintenance cost, reduces filter core damage and secondary pollution risk.

Description

Mining vehicle air filter assembly and blowback control method thereof

Technical Field

The invention belongs to the technical field of air filters, and particularly relates to a mining vehicle air filter assembly and a blowback control method thereof.

Background

The air filter is mainly used for filtering air in engineering locomotives, automobiles, agricultural locomotives, laboratories, sterile operation rooms and various precision operation rooms.

The contradiction (the air inflow, the filtering efficiency and the pressure drop requirement of an engine and the limitation of an arrangement space) between the severe dust environment of a mining area and the limited dust containing capacity of an air filtering system of a mining vehicle faces the problem of non-standardization, non-intellectualization and automation of frequent maintenance of the air inlet system and maintenance of an air filter.

The filter element is easy to damage due to non-standardized maintenance, secondary ash entrance risks of the pipeline are easy to cause, and meanwhile, when part of users replace the air filter element, the filter element with poor quality and poor adaptability is possibly selected for assembly and use due to low quality awareness of the air filter element, so that the air filter efficiency is low and the service life is short; the non-intelligent maintenance easily causes improper maintenance time; the non-automatic maintenance not only can lead to the parking maintenance frequency to be high, and complex operation, maintenance cost are high moreover, and the operating efficiency reduces. And the traditional air filter element is directly communicated with the atmosphere and is seriously influenced by the external environment and weather.

Disclosure of Invention

In order to solve the problems, the invention provides the mining vehicle air filter assembly and the back blowing control method thereof, wherein the air filter is designed in a closed manner, so that the influence of the external environment and weather is effectively avoided; the pre-filter, the filtering and back-blowing system and the dust collection system are integrally mounted on the bracket assembly, so that the space occupation can be effectively reduced, and the integration is high; and realize air filter's full-automatic blowback maintenance, the air cleaner maintenance opportunity is judged to intelligence, reduces artifical maintenance cost, also reduces filter core and damages risk and secondary pollution risk.

The invention is realized by the following technical scheme on one hand:

an air filter assembly of a mining vehicle comprises a prefilter, a filtering blowback system and a dust collection system which are sequentially arranged from top to bottom through a bracket assembly; the prefilter is of a cyclone centrifugal structure and comprises a prefilter air inlet with a downward opening and a prefilter air outlet;

the filtering and back-blowing system comprises an air filter and a back-blowing air storage tank which are arranged up and down; the air filter comprises a filter shell with a horizontal cylindrical shell structure, a cylindrical air filter element and a safety filter element are arranged in the filter shell, and an annular channel is formed between the air filter element and the safety filter element; the upper side and the lower side of the circumferential side wall of the filter shell are respectively provided with a filter air inlet and a filter dust exhaust port which are connected with the prefilter air outlet, and one end surface of the filter shell is provided with a filter air outlet which can be connected with an engine inlet; the back-blowing air storage tank is communicated with the annular channel through a back-blowing air inlet pipe;

the dust collection system comprises a dust removal pump, and an inlet of the dust removal pump is connected with a dust discharge port of the filter.

The invention is further improved that the prefilter comprises a prefilter shell in the shape of a vertical cylindrical shell, and centrifugal blades are rotatably arranged in the prefilter shell along the axial lead of the prefilter shell; a dust exhaust port of the prefilter is formed in the circumferential side surface of the prefilter shell; the air inlet and the air outlet of the prefilter are arranged on the lower end face of the prefilter shell, the air outlet of the prefilter is positioned at the center, and the air inlets of the prefilter are uniformly and annularly distributed at the periphery.

The invention is further improved that the other end surface of the filter shell is provided with a rear cover; the air filter element is provided with an identification chip, and the rear cover is provided with an identification module corresponding to the identification chip.

The invention is further improved in that a negative pressure sensor is arranged on the air outlet of the filter.

The invention is further improved in that a pressure reducing valve is arranged on the back-blowing air inlet pipe.

The invention further improves the structure that a back-blowing electromagnetic valve is arranged at the outlet of the back-blowing air storage tank, and a back-blowing controller capable of controlling the on-off of the back-blowing electromagnetic valve is also arranged in the back-blowing air storage tank.

The invention further improves the structure and the method, and also comprises a control panel capable of controlling a blowback mode and a negative pressure value.

The other aspect of the invention is realized by the following technical scheme:

a blowback control method for an air filter assembly of a mining vehicle comprises the following steps:

the method comprises the following steps: when the negative pressure sensor reaches a set negative pressure value, the engine is in a stop state at the same time, and the control panel is operated to transmit signals to the back flushing controller;

step two: the identification module detects the identification chip in a wireless communication mode, reads the information of the identification chip and transmits the information to the back flushing controller;

step three: after the back-blowing controller identifies that the information is correct, the back-blowing electromagnetic valve is controlled to be opened, high-pressure gas in the back-blowing gas storage tank is depressurized by the pressure reducing valve, enters the annular gas passage through the back-blowing gas inlet pipe, fills the whole annular gas passage, forms back-blowing gas flow from inside to outside, and enables dust on the air filter element to fall off;

step four: the fallen dust is pumped out through the dust collection pump by the dust collection pipe along with the blowback airflow and is discharged through the dust discharge pipe.

According to the technical scheme, the invention has the beneficial effects that:

the back-blowing controller is adopted to control high-pressure gas in the back-blowing gas storage tank to fill an annular channel in the air filter for a short time, so that back-blowing gas flow from inside to outside is formed, dust on the outer surface of the air filter element falls, full-automatic maintenance is realized, the manual maintenance cost is reduced, and the filter element damage risk and the secondary pollution risk caused by manual maintenance are also reduced; the maintenance time of the air filter is intelligently judged according to the negative pressure value of the negative pressure sensor; the recognition module is used for recognizing the information of the recognition chip on the air filter element, and the function of automatically removing dust on the air filter element can be executed after the information is judged to be correct, so that the authenticity of the air filter element can be effectively recognized, a user is prompted to correctly use a genuine air filter element, and an engine is effectively protected; the air filter element is completely wrapped by the filter shell and the rear cover, so that the performance of the air filter element can be protected from being influenced by the environment and weather. And the prefilter, the filtering and back-blowing system and the dust collection system are integrally arranged on the bracket assembly, so that the space occupation can be effectively reduced, and the integration is high.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings required to be used in the description will be briefly introduced below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a schematic diagram of a prefilter structure in accordance with an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a back-flushing filter system according to an embodiment of the present invention.

Fig. 4 is a schematic view of the internal structure of an air cleaner according to an embodiment of the present invention.

Fig. 5 is a schematic view of a control panel structure according to an embodiment of the present invention.

FIG. 6 is a schematic view of a dust collection system according to an embodiment of the present invention.

FIG. 7 is a schematic view of a bracket assembly according to an embodiment of the present invention.

Fig. 8 is a schematic control diagram according to an embodiment of the present invention.

In the drawings: 1. the device comprises a prefilter, 2, a filtration blowback system, 3, a dust collection system, 4, a bracket assembly, 5, a prefilter shell, 6, a prefilter dust exhaust port, 7, a prefilter air inlet, 8, a prefilter air outlet, 9, a centrifugal blade, 10, an air filter, 11, a negative pressure sensor, 12, a pressure reducing valve, 13, a blowback electromagnetic valve, 14, a blowback controller, 15, a blowback air storage tank, 16, a control panel, 17, an identification chip, 18, an identification module, 19, a rear cover, 20, a filter shell, 21, an air filter element, 22, a filter air inlet, 23, an annular channel, 24, a filter air outlet, 25, a blowback air inlet pipe, 26, a filter dust exhaust port, 27, a dust removal pump, 28, a dust collection pipe, 29 and a dust exhaust pipe.

Detailed Description

In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present embodiment, and it is obvious that the embodiments described below are only a part of embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of protection of this patent.

As shown in FIGS. 1-7, the invention discloses an air filter assembly of a mining vehicle, which comprises a prefilter 1, a filter blowback system 2 and a dust collection system 3 which are sequentially arranged from top to bottom through a bracket assembly 4; the prefilter 1 is of a cyclone centrifugal structure and comprises a prefilter air inlet 7 and a prefilter air outlet 8, wherein the openings of the prefilter air inlet 7 and the prefilter air outlet 8 are downward;

the filtering and back-blowing system 2 comprises an air filter 10 and a back-blowing air storage tank 15 which are arranged up and down; the air filter 10 comprises a filter shell 20 with a horizontal cylindrical shell structure, a cylindrical air filter element 21 and a safety filter element are arranged in the filter shell 20, and an annular channel 23 is formed between the air filter element 21 and the safety filter element; the upper side and the lower side of the circumferential side wall of the filter shell 20 are respectively provided with a filter air inlet 22 and a filter dust exhaust port 26 which are connected with the prefilter air outlet 8, and the filter air inlet 22 is connected with the prefilter air outlet 8 through a flexible rubber pipe; a filter air outlet 24 which can be connected with an engine inlet is arranged on one end face of the filter shell 20; the back-blowing air storage tank 15 is communicated with the annular channel 23 through a back-blowing air inlet pipe 25;

the dust collection system 3 comprises a dust collection pump 27, an inlet of the dust collection pump 27 is connected with a dust discharge port 26 of the filter through a dust collection pipe 28, an outlet of the dust collection pump 27 is connected with a dust discharge pipe 29, the dust discharge pipe 29 is fixed on the support assembly 4 through an L-shaped support, and the dust collection pump 27 is arranged on the side face of the back blowing air storage tank 15.

This air cleaner assembly is normal during operation, and in the external air got into prefilter 1 through prefilter air inlet 7, the air after centrifugal separation passed through prefilter gas outlet 8, filter air inlet 22 and got into air cleaner 10 in, filtered through air filter 21 and the safety filter element in the air cleaner 10, got into the engine through filter gas outlet 24, filtered through 1 one-level of prefilter and air cleaner 10 second grade, guaranteed the cleanliness factor that the engine was admitted air. When the air filter element 21 is seriously blocked, and the engine is in a stop state, the back-blowing air storage tank 15 blows high-pressure air into the annular air passage 23 through the back-blowing air inlet pipe 25 to form back-blowing air flow from inside to outside, so that dust on the air filter element 21 falls off; the fallen dust is pumped out through a dust suction pipe 28 by a dust removal pump 27 along with the blowback airflow and is discharged through a dust discharge pipe 29; thereby realizing good back-blowing cleaning effect of the air filter 10 and avoiding secondary ash feeding risk. The whole structure is simple, the use is convenient, and the air filter 10 is of a closed design, so that the influence of the external environment and the weather is effectively avoided; and the prefilter 1, the filtering blowback system 2 and the dust collection system 3 are integrally arranged on the bracket assembly 4, so that the space occupation can be effectively reduced, and the integration is high.

Wherein, safe filter core has two effects: 1. acting as a backup filter, in the special case of damage or incorrect installation of the air filter 21. Such damage may be insignificant, not readily discernible, and may be caused during operation or during servicing of the filter element. In addition, the air filter 21 may not be correctly attached, and a good sealing condition may not be achieved. 2. Protecting the engine and also preventing dirt and other impurities from entering the clean air side of the air induction system when the air filter element 21 is removed during maintenance.

Wherein, the volume of the back-blowing gas storage tank is 15L, the storage pressure is not less than 0.5MPa, and the working pressure is 0.6MPa-1.0MPa; the back-blowing air storage tank 15 is provided with a pressure regulating valve of 0MPa-1.0MPa and a pressure relief valve of 1.0MPa, when the pressure of the back-blowing air storage tank 15 is smaller than the pressure of the pressure regulating valve, the back-blowing air storage tank 15 is inflated, and when the pressure is larger than the pressure of the pressure relief valve, the pressure relief valve is opened to relieve the pressure.

As shown in fig. 2, the prefilter 1 includes a prefilter housing 5 in the form of a vertical cylindrical housing, and centrifugal blades 9 are rotatably mounted in the prefilter housing 5 along the axial center line thereof; the circumferential side surface of the prefilter shell 5 is provided with a prefilter dust exhaust port 6 with a shutter structure; the air inlet 7 and the air outlet 8 of the prefilter are arranged on the lower end face of the prefilter housing 5, the air outlet 8 of the prefilter is positioned at the center, and the air inlets 7 of the prefilter are uniformly and annularly distributed at the periphery. Air is sucked in through a prefilter air inlet 7 on the outer ring of the lower end face of a prefilter shell 5, centrifugal blades 9 rotate to carry out centrifugal separation on the air, dust is discharged outside through a prefilter dust discharge port 6, and air filtered at the first stage enters an air filter 10 through a prefilter air outlet 8.

As shown in fig. 3, the other end face of the filter case 20 is provided with a rear cover 19; the air filter element 21 is provided with an identification chip 17, and the rear cover 19 is provided with an identification module 18 corresponding to the identification chip 17. The distance between the identification module 18 and the identification chip 17 is not more than 100mm, the identification module 18 reads the authenticity information of the identification chip 17 in a wireless communication mode, the use of a genuine product air filter element 21 is ensured, an engine is effectively protected, and the air filter element 21 can be efficiently filtered. The rear cover 19 is detachably connected with the filter housing 20 through a snap-fit assembly, so that the air filter element 21 is well sealed, and the air filter element 21 is convenient to disassemble, assemble and replace.

Wherein, the filter air outlet 24 is provided with a negative pressure sensor 11. The blockage condition of the air filter element 21 can be judged through the negative pressure value detected by the negative pressure sensor 11, so that the air filter element 21 is cleaned in a back blowing mode or replaced in time, the air filter 10 is efficiently filtered, and the use reliability and intelligent detection are guaranteed.

Wherein, the blowback air inlet pipe 25 is provided with a pressure reducing valve 12. Because the air pressure of the back-blowing air storage tank 15 is large, the air is decompressed by the decompression valve 12 and then enters the annular channel 23 to back-blow and clean the air filter element 21, the impact of the over-large air flow on the air filter element 21 is avoided, and the use safety is ensured.

Wherein, the outlet of the back-blowing air storage tank 15 is provided with a back-blowing electromagnetic valve 13, and the back-blowing air storage tank 15 is also internally provided with a back-blowing controller 14 which can control the on-off of the back-blowing electromagnetic valve 13. The back-blowing controller 14 automatically controls the back-blowing electromagnetic valve 13 to be closed, so that the automation and the high efficiency of the back-blowing effect can be realized, manual excessive operation is not needed, the use convenience is ensured, and the labor is saved. The back flushing electromagnetic valve 13 has the working voltage of 24V DC and is normally closed, and the working pressure is 0.6MPa-1.2MPa. The working voltage of the back flushing controller 14 is 24V DC, the output is controlled to be 24V 2A, the working temperature is-40-85 ℃, and the protection level is IP67.

Wherein, blowback gas holder 15, blowback solenoid valve 13, relief pressure valve 12, blowback intake pipe 25 pass through the rubber tube and connect gradually, and blowback solenoid valve 13 and identification module 18 all with blowback controller 14 electric connection.

Wherein a control panel 16 is provided in the vehicle cab (or integrated on the cab instrument desk). The control panel 16 functions include setting a negative pressure value and switching a blowback mode. The back-blowing mode includes an automatic mode and a manual mode. The control panel 16 has 4 keys "D", "M", "plus", "minus", the pressing of the key "D" can reverse the blow in the automatic mode (the pressing of the key "D" in the manual mode is ineffective), the pressing of the key "M" can switch between the automatic mode and the manual mode, and the pressing of the keys "+" and "minus" can set the negative pressure value. The back-blowing controller 14 analyzes the data returned by the negative pressure sensor 11, converts the data into a negative pressure value and displays the negative pressure value on the control panel 16, and the control panel 16 sends out light for prompting the driver that the resistance is normal, the resistance is high, the resistance is over-limit and the like according to the specific negative pressure value.

The invention also discloses a back flushing control method of the mining vehicle air filter assembly, which comprises the following steps:

the method comprises the following steps: when the negative pressure sensor 11 reaches a set negative pressure value and the engine is in a stop state, the operation control panel 16 transmits a signal to the back flushing controller 14;

step two: the identification module 18 detects the identification chip 17 in a wireless communication mode, reads information of the identification chip 17 and transmits the information to the blowback controller 14;

step three: after the information is identified correctly by the back-blowing controller 14, the back-blowing electromagnetic valve 13 is controlled to be opened, high-pressure gas in the back-blowing gas storage tank 15 is depressurized by the pressure reducing valve 12, enters the annular gas passage 23 through the back-blowing gas inlet pipe 25 and fills the whole annular gas passage 23 to form back-blowing gas flow from inside to outside, so that dust on the air filter element 21 falls off;

step four: the fallen dust is sucked out through the dust suction pipe 28 by the dust suction pump 27 with the blowback air flow, and is discharged through the dust discharge pipe 29.

Blowback has an automatic mode and a manual mode:

an automatic mode: when the negative pressure sensor 11 reaches the set negative pressure value and the vehicle key switch is in the power-off condition, the control panel key M is pressed, the back-flushing controller 14 automatically reads the information of the identification chip 17 after receiving the action signal, and drives the back-flushing electromagnetic valve 13 to be opened for 3 seconds and the dust-removing pump 27 to work for 15 seconds after the information is judged to be correct.

Manual mode: after an action signal is artificially provided, the information of the identification chip 17 is automatically read, and after the information is judged to be correct, the blowback electromagnetic valve 13 is driven to be opened for 3 seconds, and the dust removal pump 27 is driven to work for 15 seconds. (this mode is not limited by the negative pressure value).

The mining vehicle air filter assembly and the back blowing control method thereof adopt the back blowing controller to control high-pressure gas in the back blowing gas storage tank to fill an annular channel in the air filter for a short time, so as to form back blowing gas flow from inside to outside, so that dust on the outer surface of an air filter element falls off, full-automatic maintenance is realized, the manual maintenance cost is reduced, and the filter element damage risk and the secondary pollution risk caused by manual maintenance are also reduced; the maintenance time of the air filter is intelligently judged according to the negative pressure value of the negative pressure sensor; the recognition module is used for recognizing the information of the recognition chip on the air filter element, and the function of automatically clearing dust on the air filter element can be executed after the information is judged to be correct, so that the authenticity of the air filter element can be effectively recognized, a user is prompted to correctly use a genuine air filter element, and an engine is effectively protected; the air filter element is completely wrapped by the filter shell and the rear cover, so that the performance of the air filter element can be protected from being influenced by the environment and weather. And the prefilter, the filtering blowback system and the dust collection system are integrally arranged on the bracket assembly, so that the space occupation can be effectively reduced, and the integration is high.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The terms "upper", "lower", "outside", "inside" and the like in the description and claims of the present invention and the above drawings are used for distinguishing relative positions if any, and are not necessarily given qualitatively. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The mining vehicle air filter assembly is characterized by comprising a prefilter (1), a filtering and back-blowing system (2) and a dust collection system (3) which are sequentially arranged from top to bottom through a bracket assembly (4); the prefilter (1) is of a cyclone centrifugal structure and comprises a prefilter air inlet (7) with a downward opening and a prefilter air outlet (8); the filtering and back-blowing system (2) comprises an air filter (10) and a back-blowing air storage tank (15) which are arranged up and down; the air filter (10) comprises a filter shell (20) with a horizontal cylindrical shell structure, a cylindrical air filter element (21) and a safety filter element are arranged in the filter shell (20), and an annular channel (23) is formed between the air filter element (21) and the safety filter element; the upper side and the lower side of the circumferential side wall of the filter shell (20) are respectively provided with a filter air inlet (22) and a filter dust exhaust port (26) which are connected with the prefilter air outlet (8), and one end surface of the filter shell (20) is provided with a filter air outlet (24) which can be connected with an engine inlet; the back-blowing air storage tank (15) is communicated with the annular channel (23) through a back-blowing air inlet pipe (25); the dust collection system (3) comprises a dust removal pump (27), and an inlet of the dust removal pump (27) is connected with a dust discharge port (26) of the filter.

2. The mining vehicle air filter assembly according to claim 1, characterized in that the prefilter (1) comprises a prefilter housing (5) in the form of an upright cylindrical housing, the prefilter housing (5) having mounted therein centrifugal vanes (9) rotatably mounted along its axial center line; a prefilter dust exhaust port (6) is formed in the circumferential side surface of the prefilter shell (5); the air inlet (7) and the air outlet (8) of the prefilter are arranged on the lower end face of the prefilter shell (5), the air outlet (8) of the prefilter is located at the center, and the air inlets (7) of the prefilter are uniformly and annularly distributed at the periphery.

3. A mining vehicle air filter assembly according to claim 1, characterised in that the other end face of the filter housing (20) is provided with a rear cover (19); an identification chip (17) is arranged on the air filter element (21), and an identification module (18) corresponding to the identification chip (17) is arranged on the rear cover (19).

4. A mining vehicle air filter assembly according to claim 1, characterised in that a negative pressure sensor (11) is provided on the filter air outlet (24).

5. The mining vehicle air cleaner assembly of claim 1, characterized in that a pressure relief valve (12) is mounted to the blowback air intake duct (25).

6. The mining vehicle air filter assembly according to claim 1, wherein a blowback solenoid valve (13) is installed at an outlet of the blowback air storage tank (15), and a blowback controller (14) capable of controlling the blowback solenoid valve (13) to open and close is further installed in the blowback air storage tank (15).

7. The mining vehicle air filter assembly of claim 1, further comprising a control panel (16) configured to control the blowback mode and the negative pressure value.

8. A blowback control method for a mining vehicle air filter assembly is characterized by comprising the following steps: the method comprises the following steps: when the negative pressure sensor (11) reaches a set negative pressure value, the engine is in a stop state at the same time, and the operation control panel (16) transmits a signal to the back flushing controller (14); step two: the identification module (18) detects the identification chip (17) in a wireless communication mode, reads information of the identification chip (17) and transmits the information to the back flushing controller (14); step three: after the reverse blowing controller (14) identifies correct information, the reverse blowing electromagnetic valve (13) is controlled to be opened, high-pressure gas in the reverse blowing gas storage tank (15) is depressurized by the pressure reducing valve (12), enters the annular gas channel (23) through the reverse blowing gas inlet pipe (25), fills the whole annular gas channel (23), forms reverse blowing gas flow from inside to outside, and enables dust on the air filter element (21) to fall off; step four: the fallen dust is sucked out through a dust suction pipe (28) by a dust removal pump (27) along with the blowback airflow and is discharged through a dust discharge pipe (29).