Circulating fluidized bed boiler tail gas treatment device

Abstract

The application discloses a circulating fluidized bed boiler tail gas treatment device and relates to the technical field of circulating fluidized bed boilers, which comprises a cylinder and a tail gas pipe; a filtering round net plate is arranged in the cylinder; a rotating column is rotatably connected to the inside of the tail gas pipe near the filtering cavity; a stepping motor is connected to the outer wall of the tail gas pipe, and the main shaft end of the stepping motor is connected to one end of the rotating column; and a plurality of heating cavities are circumferentially arranged on the rotating column. The heating cavities distributed on the rotating column can be used for batch pushing of tail gas, and the distributed heating cavities pass through the position of the arc plate in sequence. Whenever a heating cavity is docked to the position of the arc plate, the heating cavity heats the tail gas, and when the temperature of the tail gas rises to the required temperature, the temperature sensor drives the rotating column to rotate through the stepping motor, so that the heated tail gas can advance to contact the atomized ammonia water, and the problem that the reaction is insufficient and the tail gas treatment effect is affected due to the fact that the temperature of the tail gas does not reach the set temperature can be avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circulating fluidized bed boilers, in particular to a circulating fluidized bed boiler tail gas treatment device. BACKGROUND

[0002] In recent years, in order to prevent and control air pollution, improve environmental quality, and further reduce the emission intensity of pollution sources, the environmental protection department has increasingly high requirements for the emission limit value of air pollutants. Since the circulating fluidized bed boiler flue gas contains a large amount of nitrogen oxides, direct emission will pollute the environment, and therefore non-catalytic reduction method is needed for denitration treatment, that is, nitrogen oxides are reduced to water and nitrogen by adding a nitrogen-containing reactant such as ammonia water in the flue gas with a temperature of 800-1200℃;

[0003] Chinese patent authorization announcement No. CN219231958U, named circulating fluidized bed boiler flue gas treatment device, including shell, the inside of the shell is installed through the injection agent, the inside of the shell is fixedly installed with multiple groups of resistance plates, the side of the resistance plate relative to the filter screen is installed with electric heating wire, the inside of the shell is installed with filter screen, the scheme relies on the filter screen to filter the impurities and dust in the tail gas first, and then the tail gas passes through the resistance plate, the electric heating wire on the resistance plate is heated to reach the reaction temperature, and then reacts with the atomized ammonia water sprayed by the injection agent to realize the treatment;

[0004] The above-mentioned prior art scheme has the following disadvantages: although the above-mentioned scheme can rely on the electric heating wire to heat and warm the tail gas, it cannot be determined that the tail gas can reach the corresponding temperature range after passing through each resistance plate. The resistance plate only prolongs the path of the tail gas, but cannot ensure that the tail gas is warmed to the required temperature after passing through. Once the tail gas does not reach the required temperature, the nitrogen oxides in the tail gas cannot be fully reduced, that is, the treatment effect is not good enough. In addition, the filter screen used in the prior art cannot be automatically cleaned. Once the filtered impurities exceed, the mesh holes of the filter screen are blocked, which causes the filter screen to be unable to filter, and manual regular cleaning cannot guarantee timeliness. SUMMARY

[0005] The purpose of the present application is to provide a circulating fluidized bed boiler tail gas treatment device to solve the technical problem that the circulating fluidized bed boiler tail gas treatment device in the prior art cannot guarantee that the tail gas is warmed to the required reaction temperature during reaction treatment, affecting the reaction treatment effect.

[0006] The technical problem solved by the present application can be realized by the following technical scheme:

[0007] The circulating fluidized bed boiler tail gas treatment device comprises a cylinder and a tail gas pipe.

[0008] The inside of the cylinder is provided with a filtering cavity, the lower side of the cylinder is provided with a cleaning cavity, the tail gas pipe is connected to one side of the cylinder and communicates with the filtering cavity, and the inside of the cylinder is provided with a filtering round net plate in a matched mode.

[0009] The inside of the filtering cavity is connected with a driving motor, the main shaft end of the driving motor is connected with the center position of the filtering round net plate, the inner wall of one side of the cleaning cavity is rotatably connected with an extension connecting rod, the extension end of the extension connecting rod is connected with a plate-shaped brush head, the rotating end and the extension end of the extension connecting rod are connected with a spring, and the main shaft end of the driving motor and the extension connecting rod are connected with a transmission impact mechanism in a matched mode.

[0010] The inside of the tail gas pipe close to the filtering cavity is rotatably connected with a rotating column in a matched mode, the outer wall of the tail gas pipe is connected with a stepping motor, the main shaft end of the stepping motor is connected with one end of the rotating column, a plurality of heating cavities are circumferentially arranged on the rotating column, the inner walls on the two sides of each heating cavity are connected with an electric heating sheet, the upper and lower inner walls of the tail gas pipe are connected with arc plates matched with the rotating column, the arc plate at the upper inner wall of the tail gas pipe is connected with a temperature sensor electrically connected with the stepping motor, and an electricity connection assembly is arranged in a matched mode between the arc plate at the upper inner wall of the tail gas pipe and the electric heating sheet.

[0011] The top of the end of the tail gas pipe away from the cylinder is connected with an ammonia water atomizing nozzle assembly, and the bottom of the end of the tail gas pipe away from the cylinder is connected with a discharge cylinder aligned with the ammonia water atomizing nozzle assembly.

[0012] As a further scheme of the present application, the transmission impact mechanism comprises a driving gear and a magnet block, the driving gear is coaxially connected to the main shaft end of the driving motor, the magnet block is connected to one end of the driving gear, the rotating end of the extension connecting rod is coaxially connected with a linkage gear engaged with the driving gear, and the extension end of the extension connecting rod is connected with an iron disc matched with the magnet block.

[0013] As a further scheme of the present application, the electricity connection assembly comprises a conductive sheet group and a plurality of ball-shaped electricity connection ends, the conductive sheet group is connected to the arc plate at the upper inner wall of the tail gas pipe, and each ball-shaped electricity connection end is connected to a corresponding electric heating sheet.

[0014] As a further scheme of the present application, the lower side of the discharge cylinder is provided with an expanding box, the bottom of the expanding box is connected with a liquid discharge pipe, and a plurality of air holes are circumferentially arranged on the side wall of the expanding box.

[0015] As a further scheme of the present application, a spiral pipe is connected between the bottom of the discharge cylinder and the top of the expanding box.

[0016] As a further scheme of the present application: the inner diameter of the spiral pipe and the drain pipe is smaller than the inner diameter of the flared box.

[0017] As a further scheme of the present application: the bottom of the cylinder is provided with a detachable bottom plate.

[0018] As a further scheme of the present application: the filter cavity is connected with a check valve away from the tail gas pipe.

[0019] The present application has the following beneficial effects:

[0020] 1. The heating cavities distributed on the rotating column can be used to push the tail gas in batches, and the distributed heating cavities pass through the position of the arc plate in turn. When the heating cavity is docked to the position of the arc plate, the heating wire in the heating cavity is powered to heat, which facilitates heating and warming of the tail gas. When the temperature of the tail gas rises to the required temperature, the temperature sensor drives the stepping motor to rotate the rotating column, so as to push the warmed tail gas to contact the atomized ammonia water, realize effective reaction, and avoid insufficient reaction caused by the temperature of the tail gas not reaching the set temperature, which affects the tail gas treatment effect.

[0021] 2. The driving motor can drive the filter round net plate to rotate, so as to replace the part in the filter cavity with the filter round net plate, and the part of the filter round net plate replaced from the filter cavity to the cleaning cavity contacts the plate-shaped brush head to obtain cleaning effect. When the driving motor drives the filter round net plate to rotate, the plate-shaped brush head is also driven to rotate by the gear combination, and the magnet block connected to the driving gear at the end of the driving motor shaft intermittently acts on the iron disc on the telescopic connecting rod connected to the plate-shaped brush head, so that the telescopic connecting rod realizes telescopic linkage, so that the plate-shaped brush head impacts the filter round net plate in the cleaning cavity, so as to clean the filter round net plate sufficiently, so that the cleaned filter round net plate returns to the filter cavity to continue filtering, and realizes continuous and effective filtering. BRIEF DESCRIPTION OF DRAWINGS

[0022] The present application will be further described below with reference to the accompanying drawings.

[0023] Figure 1 is a schematic diagram of the overall structure of the present application;

[0024] Figure 2 is Figure 1 is an enlarged structure schematic diagram of position A in the present application;

[0025] Figure 3 is a left view cross-sectional structure schematic diagram of the cooperation and connection of the cylinder and the filter round net plate in the present application;

[0026] Figure 4 is a structure schematic diagram of the mutual adsorption of the magnet block and the iron disc in the present application;

[0027] Figure 5 is Figure 1 an enlarged structural schematic view at B in figure

[0028] Figure 6 is a left view structural schematic view of the tail gas pipe and the rotating column in the application.

[0029] In the figure: 1, cylinder; 2, check valve; 3, filter round mesh plate; 4, filter cavity; 5, driving motor; 6, cleaning cavity; 7, detachable bottom plate; 8, tail gas pipe; 9, ammonia water atomizing nozzle assembly; 10, rotating column; 11, heating cavity; 12, discharge cylinder; 13, spiral pipe; 14, flared box; 15, air hole; 16, plate-shaped brush head; 17, iron round piece; 18, spring; 19, telescopic connecting rod; 20, linkage gear; 21, driving gear; 22, magnet block; 23, electric heating sheet; 24, spherical electric connection end; 25, circular arc plate; 26, conductive piece group; 27, temperature sensor; 28, stepping motor. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0031] As Figures 1-6 shown, the circulating fluidized bed boiler tail gas treatment device comprises a cylinder 1 and a tail gas pipe 8, a filter cavity 4 is arranged on the upper side inside the cylinder 1, a cleaning cavity 6 is arranged on the lower side inside the cylinder 1, the filter cavity 4 and the cleaning cavity 6 are separated by a plate body, the tail gas pipe 8 is connected to one side of the cylinder 1, and the tail gas pipe 8 is in communication with the filter cavity 4, a check valve 2 is connected to the side of the filter cavity 4 away from the tail gas pipe 8, the check valve 2 is a tail gas inlet end, which facilitates the tail gas to enter the filter cavity 4, and the tail gas cannot flow back through the check valve 2, a filter round mesh plate 3 is arranged in the cylinder 1 in a matching manner, a part of the filter round mesh plate 3 matches the filter cavity 4, and the other part matches the cleaning cavity 6, after the boiler tail gas enters the filter cavity 4 through the check valve 2, the boiler tail gas can pass through the filter round mesh plate 3 in the filter cavity 4, so that tail gas filtration is realized;

[0032] The inside of the filtering cavity 4 is fixedly connected with a driving motor 5, the main shaft end of the driving motor 5 is connected with the center position of the filtering round net plate 3, the driving motor 5 drives the filtering round net plate 3 to rotate, and the filtering round net plate 3 is conveniently alternately operated between the filtering cavity 4 and the cleaning cavity 6; the side inner wall of the cleaning cavity 6 is rotatably connected with an extension connecting rod 19, the extension end of the extension connecting rod 19 is connected with a plate-shaped brush head 16, the rotating end and the extension end of the extension connecting rod 19 are connected with a spring 18, the main shaft end of the driving motor 5 and the extension connecting rod 19 are cooperatively connected with a transmission impact mechanism, the transmission impact mechanism comprises a driving gear 21 and a magnet block 22, the driving gear 21 is coaxially connected with the main shaft end of the driving motor 5, the magnet block 22 is connected with one end of the driving gear 21, the rotating end of the extension connecting rod 19 is coaxially connected with a linkage gear 20 which is engaged with the driving gear 21, and the extension end of the extension connecting rod 19 is connected with an iron round piece 17 which cooperates with the magnet block 22;

[0033] The driving motor 5 drives the filtering round net plate 3 to rotate, so that the filtering round net plate 3 which filters impurities in the filtering cavity 4 is partially rotated into the cleaning cavity 6, and at the same time the main shaft end of the driving motor 5 drives the driving gear 21 to rotate, the driving gear 21 drives the linkage gear 20 to rotate, so that the extension connecting rod 19 drives the plate-shaped brush head 16 to rotate, when the magnet block 22 is away from the iron round piece 17, the extension connecting rod 19 remains in the extended state, and the plate-shaped brush head 16 abuts against the filtering round net plate 3, so as to conveniently clean the filtering round net plate 3 which is rotated into the cleaning cavity 6 by rotation; during the rotation of the driving gear 21, when the magnet block 22 rotates to the position close to the iron round piece 17, the magnet block 22 generates magnetic attraction force to the iron round piece 17, so that the iron round piece 17 drives the extension end of the extension connecting rod 19 to contract, in this process, the spring 18 is compressed to generate elastic force, and the plate-shaped brush head 16 is separated from the filtering round net plate 3, when the magnet block 22 is away from the iron round piece 17 again, the extension end of the extension connecting rod 19 drives the plate-shaped brush head 16 to impact the filtering round net plate 3 by the elastic force of the spring 18, so as to fully clean the dust and impurities attached to the filtering round net plate 3, and the cleaned filtering round net plate 3 is rotated into the filtering cavity 4 again to filter the tail gas, so as to continuously filter the tail gas by the filtering round net plate 3;

[0034] The bottom of the cylinder 1 is provided with a detachable bottom plate 7, the detachable bottom plate 7 can detachably open the bottom of the cylinder 1, so as to take out the dust and impurities cleaned in the cleaning cavity 6;

[0035] The tail gas pipe 8 is internally connected with a rotating column 10 near one side of the filtering cavity 4, the rotating column 10 is in a horizontal position, the outer wall of the tail gas pipe 8 is connected with a stepping motor 28, and the main shaft end of the stepping motor 28 is connected with one end of the rotating column 10, a plurality of heating cavities 11 are circumferentially arranged on the rotating column 10, the inner walls on both sides of each heating cavity 11 are connected with an electric heating sheet 23, the upper and lower inner walls of the tail gas pipe 8 are connected with arc plates 25 matched with the rotating column 10, the arc plate 25 at the upper inner wall of the tail gas pipe 8 is connected with a temperature sensor 27 electrically connected with the stepping motor 28, the temperature sensor 27 is used for detecting the temperature of the tail gas, when the temperature of the tail gas reaches the set reaction temperature, the stepping motor 28 is triggered to operate, driving the rotating column 10 to rotate clockwise by a certain angle, and the angle is just the central angle of the heating cavity 11 corresponding to the arc plate 25; the arc plate 25 at the upper inner wall of the tail gas pipe 8 and the electric heating sheet 23 are matched with an electricity connection assembly, the electricity connection assembly comprises a conductive sheet group 26 and a spherical electricity connection end 24, the conductive sheet group 26 is connected to the arc plate 25 at the upper inner wall of the tail gas pipe 8, the conductive sheet group 26 is connected to an external power supply, the spherical electricity connection end 24 is provided with a plurality of spherical electricity connection ends 24, and each spherical electricity connection end 24 is connected to the corresponding electric heating sheet 23 and electrically connected, when each heating cavity 11 is rotated to the position matched with the arc plate 25 at the upper position by the rotating column 10, the spherical electricity connection end 24 on the electric heating sheet 23 of the inner wall on both sides of the heating cavity 11 is in contact with the conductive sheet group 26 to electrically connect the electric heating sheet 23, so as to heat the electric heating sheet 23, and facilitate heating and warming of the tail gas in the heating cavity 11, when the temperature of the tail gas in the heating cavity 11 reaches the set temperature, the temperature sensor 27 drives the rotating column 10 to rotate by a certain angle, so that the heated heating cavity 11 rotates away from the matched arc plate 25, so as to make the heated tail gas continue to flow forward;

[0036] The tail gas pipe 8 is connected with an ammonia water atomizing nozzle assembly 9 at the top of the end away from the cylinder 1, the ammonia water atomizing nozzle assembly 9 sprays atomized ammonia water to contact and react with the heated tail gas, so that the nitrogen oxides in the tail gas are reduced to water and nitrogen;

[0037] The tail gas pipe 8 is connected with a discharge cylinder 12 aligned with the ammonia water atomizing nozzle assembly 9 at the bottom of the end away from the cylinder 1, a flared box 14 is arranged below the discharge cylinder 12, and a spiral pipe 13 is connected between the bottom of the discharge cylinder 12 and the top of the flared box 14, the spiral pipe 13 is used to prolong the contact and reaction time of the tail gas with the atomized ammonia water, so as to facilitate sufficient reaction, the bottom of the flared box 14 is connected with a liquid discharge pipe, the inner diameters of the spiral pipe 13 and the liquid discharge pipe are smaller than the inner diameter of the flared box 14, a plurality of air holes 15 are circumferentially arranged on the side wall of the flared box 14, the air holes 15 are connected with air guide pipes, so that after the reacted liquid and gas pass through the discharge cylinder 12 into the flared box 14, the gas is discharged from the air holes 15, and the liquid is discharged from the liquid discharge pipe at the bottom of the flared box 14.

[0038] The working principle of the present application is as follows: firstly, the side of the non-return valve 2 connected with the cylinder 1 is connected with the tail gas discharging end of the circulating fluidized bed boiler, so that the generated tail gas enters the filtering cavity 4 in the cylinder 1 through the non-return valve 2, and then the tail gas can pass through the filtering round mesh plate 3 in the filtering cavity 4 to realize tail gas filtering;

[0039] The driving motor 5 drives the filtering round mesh plate 3 to rotate, so that the filtering round mesh plate 3 in the filtering cavity 4 which filters impurities rotates into the cleaning cavity 6, and at the same time, the driving motor 5 drives the driving gear 21 to rotate, so that the driving gear 21 drives the linkage gear 20 to rotate, thereby driving the telescopic connecting rod 19 to drive the plate-shaped brush head 16 to rotate. When the magnet block 22 is far away from the iron round plate 17, the telescopic connecting rod 19 keeps in the elongated state, and the plate-shaped brush head 16 abuts against the filtering round mesh plate 3, so that the rotating filtering round mesh plate 3 in the cleaning cavity 6 is cleaned. When the driving gear 21 rotates, when the magnet block 22 rotates to the position close to the iron round plate 17, the magnet block 22 generates magnetic attraction force to the iron round plate 17, so that the iron round plate 17 drives the telescopic end of the telescopic connecting rod 19 to contract. In this process, the spring 18 is compressed to generate elastic force, and the plate-shaped brush head 16 is separated from the filtering round mesh plate 3. When the magnet block 22 is far away from the iron round plate 17 again, the telescopic end of the telescopic connecting rod 19 drives the plate-shaped brush head 16 to impact the filtering round mesh plate 3 by the elastic force of the spring 18, so as to clean the dust and impurities attached to the filtering round mesh plate 3. The cleaned filtering round mesh plate 3 part rotates into the filtering cavity 4 again to filter the tail gas, so that the filtering round mesh plate 3 continuously filters the tail gas.

[0040] The filtered tail gas enters the tail gas pipe 8, and then the tail gas fills into the heating cavity 11 on the side of the rotating column 10 opposite to the filtering cavity 4. At this time, the stepping motor 28 is manually controlled to feed once, so that the rotating column 10 rotates by a certain angle, and one heating cavity 11 containing the tail gas rotates to the position of the circular arc plate 25 on the upper side inner wall of the tail gas pipe 8. At this time, the spherical electric connection end 24 on the electric heating sheet 23 on the two side inner walls of the heating cavity 11 is in contact with the conductive sheet group 26 to be connected with electricity, so as to heat the electric heating sheet 23, and facilitate heating and warming the tail gas in the heating cavity 11. When the temperature of the tail gas in the heating cavity 11 reaches the set temperature, the temperature sensor 27 drives the rotating column 10 to rotate by a certain angle, so that the heated heating cavity 11 rotates away from the matched circular arc plate 25, so as to push the heated tail gas to continue to flow forward. The ammonia water atomizing nozzle assembly 9 sprays atomized ammonia water, which contacts and reacts with the heated tail gas, and the mixed tail gas and atomized ammonia water flow to the expanding box 14 along the spiral pipe 13, and fully react during the flowing process to reduce the nitrogen oxides in the tail gas into water and nitrogen. Finally, the reacted gas is discharged from the air hole 15, and the liquid is discharged from the liquid discharge pipe at the bottom of the expanding box 14.

[0041] The above detailed description has shown, by way of example, an embodiment of the application. It is specifically contemplated that the application is not limited to the embodiments described herein, but rather, the application is intended to cover all modifications and equivalents thereof falling within the scope of the application.

Claims

1. A circulating fluidized bed boiler tail gas treatment device, comprising a cylinder (1) and a tail gas pipe (8); characterized in that: an internal upper side of the cylinder (1) is provided with a filtering cavity (4), an internal lower side of the cylinder (1) is provided with a cleaning cavity (6), the tail gas pipe (8) is connected to one side of the cylinder (1), and the tail gas pipe (8) is in communication with the filtering cavity (4), an internal cooperation of the cylinder (1) is provided with a filtering round mesh plate (3), a part of the filtering round mesh plate (3) is matched with the filtering cavity (4), and another part is matched with the cleaning cavity (6); an internal end of a main shaft of the driving motor (5) is connected with a center position of the filtering round mesh plate (3); an inner wall of one side of the cleaning cavity (6) is rotatably connected with a telescopic connecting rod (19), a telescopic end of the telescopic connecting rod (19) is connected with a plate-shaped brush head (16), a rotating end and the telescopic end of the telescopic connecting rod (19) are connected with a spring (18), and a transmission impact mechanism is cooperatively connected between the main shaft end of the driving motor (5) and the telescopic connecting rod (19); an internal cooperation of one side of the tail gas pipe (8) close to the filtering cavity (4) is rotatably connected with a rotating column (10), an outer wall of the tail gas pipe (8) is connected with a stepping motor (28), a main shaft end of the stepping motor (28) is connected with one end of the rotating column (10), a plurality of heating cavities (11) are circumferentially arranged on the rotating column (10), an inner wall of each of the heating cavities (11) is connected with an electric heating sheet (23), upper and lower inner walls of the tail gas pipe (8) are connected with arc plates (25) matched with the rotating column (10), the arc plate (25) at the upper inner wall of the tail gas pipe (8) is connected with a temperature sensor (27) electrically connected with the stepping motor (28), and an electricity connection assembly is cooperatively arranged between the arc plate (25) at the upper inner wall of the tail gas pipe (8) and the electric heating sheet (23); an end of the tail gas pipe (8) away from the cylinder (1) is connected with an ammonia water atomizing nozzle assembly (9) at a top portion, and is connected with a discharge cylinder (12) aligned with the ammonia water atomizing nozzle assembly (9) at a bottom portion. The transmission impact mechanism comprises a driving gear (21) and a magnet block (22), the driving gear (21) is coaxially connected to the main shaft end of the driving motor (5), the magnet block (22) is connected to one end of the driving gear (21), the rotating end of the telescopic connecting rod (19) is coaxially connected with a linkage gear (20) engaged with the driving gear (21), and the telescopic end of the telescopic connecting rod (19) is connected with an iron round sheet (17) matched with the magnet block (22).

2. The circulating fluidized bed boiler exhaust gas treatment apparatus according to claim 1, characterized by The electricity connection assembly comprises a conductive sheet group (26) and a spherical electricity connection end (24), the conductive sheet group (26) is connected to the arc plate (25) at the upper inner wall of the tail gas pipe (8), and a plurality of the spherical electricity connection ends (24) are arranged and connected to the corresponding electric heating sheets (23).

3. The circulating fluidized bed boiler exhaust gas treatment apparatus according to claim 1, characterized by ​ 4. The circulating fluidized bed boiler exhaust gas treatment apparatus according to claim 1, characterized by The lower part of the discharge cylinder (12) is provided with a flared box (14), the bottom of the flared box (14) is connected with a liquid discharge pipe, and a plurality of air holes (15) are circumferentially arranged on the sidewall of the flared box (14).

5. The circulating fluidized bed boiler exhaust treatment apparatus according to claim 4, characterized in that, A spiral pipe (13) is connected between the bottom of the discharge cylinder (12) and the top of the flared box (14).

6. A circulating fluid bed boiler exhaust gas treatment apparatus according to claim 5, characterized in that The inner diameters of the spiral pipe (13) and the liquid discharge pipe are smaller than the inner diameter of the flared box (14).

7. The circulating fluidized bed boiler exhaust treatment apparatus according to claim 1, characterized by The bottom of the cylinder (1) is provided with a detachable bottom plate (7).

8. The circulating fluidized bed boiler exhaust treatment apparatus according to claim 1, characterized by The filter cavity (4) is connected with a check valve (2) on the side away from the tail gas pipe (8).

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