Automatic pulse type backwashing filtering system

Abstract

The invention discloses an automatic pulse type backwash filtering system, which relates to the technical field of pulse type backwash filtering, and specifically comprises a filtering tank, the bottom of the filtering tank is communicated with a liquid inlet pipe, the liquid inlet pipe is provided with an electric valve I, the side wall of the filtering tank is communicated with a liquid outlet pipe, and the inner wall of the filtering tank is fixedly provided with a partition plate by welding; a trash holding filter cartridge I is uniformly fixed between the filter tank and the partition plate through bolts; according to the invention, a plurality of trash holding filter cartridges are connected in parallel, so that the trash holding filter cartridges can work in turn in the backwashing process, the design ensures that the flow fluctuation of the system is small, and the liquid discharge mechanism and the waste liquid treatment mechanism are switched, and the system can isolate the filter cartridges needing to be cleaned from a main flow path and guide sewage to flow out from other filter cartridges during backwashing; sewage generated in the backwashing process is treated by the waste liquid treatment mechanism and then is discharged back to the filtering tank again, so that the filtering operation without shutdown, no flow interruption and water conservation is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of pulsed backwashing filtration, and particularly to an automatic pulsed backwashing filtration system. Background Art

[0002] In the field of sewage treatment, traditional filtration systems have significant limitations during the backwashing stage. For example, in the patent "An efficient sewage purification device" with the publication number CN215137212U, a cylindrical filtration housing is used to intercept sewage impurities from the outside to the inside. During backwashing, through another set of pipelines, with the bottom blocked, the cleaning liquid is discharged from the inside to the outside to wash the impurities on the outer wall of the cylindrical filtration housing.

[0003] However, the water consumption of the flushing liquid for the cylindrical filtration housing is large and the flushing effect is low;

[0004] Meanwhile, the filtration system needs to be shut down for backwashing operations to clean the solid particles and suspended matters intercepted by filtration media such as filter screens and filter elements;

[0005] However, the shutdown treatment not only reduces the overall net sewage efficiency but also causes liquid waste during the treatment process.

[0006] Therefore, we propose an automatic pulsed backwashing filtration system. Summary of the Invention

[0007] The purpose of the present invention is to provide an automatic pulsed backwashing filtration system to solve the problems raised in the above background art.

[0008] To achieve the above purpose, the present invention provides the following technical solution: An automatic pulsed backwashing filtration system includes a filtration tank. A liquid inlet pipe is connected to the bottom of the filtration tank, and an electric valve I is installed on the liquid inlet pipe. A liquid outlet pipe is connected to the side wall of the filtration tank. A partition is fixedly welded to the inner wall of the filtration tank, and a pollution interception filter cylinder I is uniformly fixed between the filtration tank and the partition by bolts. The pollution interception filter cylinder I is connected and fixed with an air pulse generator at the top of the filtration tank;

[0009] An air duct is connected and fixed inside the pollution interception filter cylinder I where the air pulse generator is located, and a nozzle is connected and fixed to the end of the air duct. A monitoring box is fixed to the outer wall support of the filtration tank by bolts;

[0010] The monitoring box includes a front-end data acquisition unit and a comparison and control unit. The front-end data acquisition unit is used to collect the weight change values of each pollution interception filter cylinder I during the monitoring period, and the comparison and control unit is used to obtain the weight change values of each pollution interception filter cylinder I and compare them with a set threshold value to generate a backwashing signal to control the opening and closing of the valve.

[0011] Further, a conversion liquid discharge mechanism is installed at the top of the filter tank. The conversion liquid discharge mechanism includes a drive shaft, a guide cylinder, and a U-shaped pipe. The output end of a motor installed at the top of the filter tank is fixed with the drive shaft. A guide cylinder is fixedly connected to the inside of the filter tank and on the partition plate. The bottom of the guide cylinder is movably connected to the U-shaped pipe. One end of the drive shaft passes through the filter tank and the guide cylinder respectively and is connected to the U-shaped pipe. An elastic plug cover is installed on the other side of the U-shaped pipe. A communication pipe is communicated with the side wall of the guide cylinder located above the partition plate.

[0012] Further, a waste liquid treatment mechanism is fixed on the side wall of the filter tank through a bracket. The waste liquid treatment mechanism includes a Y-shaped cylinder tank and a second anti-pollution filter cylinder. The Y-shaped cylinder tank is fixedly connected to the side wall bracket of the filter tank. The second anti-pollution filter cylinders are symmetrically installed inside the Y-shaped cylinder tank.

[0013] Further, one end of the communication pipe passes through the filter tank and is communicated with the Y-shaped cylinder tank. The waste liquid treatment mechanism further includes a piston rod. One end of the piston rod passes through the Y-shaped cylinder tank and is slidably connected to the tank body.

[0014] Further, liquid control pipes are symmetrically communicated on both sides of the Y-shaped cylinder tank. An electric valve II is installed on one of the liquid control pipes, and an electric valve III is installed on the other liquid control pipe.

[0015] Further, weighing sensors are evenly installed on the top of the filter tank and on one side of the anti-pollution filter cylinders. The weighing sensors monitor the weight change values of each first anti-pollution filter cylinder and send the generated signals to the monitoring box.

[0016] The filtering method of this automatic pulse type backwashing filtration system is as follows:

[0017] Online filtration monitoring of multiple filter cylinders follows the operations of sewage inlet through the inlet pipe, filtration by the first anti-pollution filter cylinder, and liquid discharge through the outlet pipe. The sewage first enters the first anti-pollution filter cylinder through the holes on the bottom partition plate of the filter tank, diffuses from the inside to the outside, the liquid level gradually rises above the outlet pipe, and after being intercepted by the first anti-pollution filter cylinder, the pollutants stay on the inner wall of the first anti-pollution filter cylinder to complete the forward filtration operation;

[0018] With the accumulation of pollutants on the inner wall of the first anti-pollution filter cylinder, its own mass increases. The weighing sensors installed on the top of the filter tank send the obtained weight values of each first anti-pollution filter cylinder to the monitoring box. The front-end data acquisition unit in the monitoring box calculates the difference of the weight values of the first anti-pollution filter cylinder obtained within the set monitoring period according to the set monitoring period, and sends the weight change value of the first anti-pollution filter cylinder to the comparison control unit for threshold comparison. When the weight change value of the first anti-pollution filter cylinder is greater than the set threshold, a backwashing signal is generated to control the pneumatic pulse generator on the corresponding first anti-pollution filter cylinder to work;

[0019] Meanwhile, the drive shaft drives the elastic blocking cover on the U-shaped pipe to move to the bottom of the first pollution interception filter cylinder corresponding to the overweight load. The second electric valve on the side liquid control pipe of the Y-shaped cylinder tank is opened, and the pneumatic pulse transmitter on the first pollution interception filter cylinder is opened. The nozzle at the end of the air guide pipe releases compressed air instantaneously through the nozzle into the liquid near the first pollution interception filter cylinder, forming a dense bubble group. The bubbles rapidly expand in the liquid, generating local high-pressure shock waves and microjets, directly flushing the filter holes, clearing the blocked particles. At the same time, the sewage to be cleaned flows into the Y-shaped cylinder tank along the connecting pipe, and after being filtered by the second pollution interception filter cylinder, it is discharged back into the filter tank again, completing the liquid filtration operation without stopping the machine or interrupting the flow.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. In the present invention, based on the significantly improved sewage treatment efficiency, a parallel structure of multiple pollution interception filter cylinders is adopted, enabling alternate operation during the backwashing process. This design ensures small fluctuations in the system flow rate, avoids shutdown caused by the backwashing of a single filter cylinder, realizes continuous and efficient sewage treatment, greatly improves the sewage treatment efficiency, ensures the continuity and stability of the treatment process, and with the installation of the pneumatic pulse generator, compressed air is instantaneously released through the nozzle, forming a dense bubble group, directly flushing the filter holes, clearing the blocked particles, and enhancing the backwashing effect;

[0022] With the innovative design of the conversion liquid discharge mechanism and the waste liquid treatment mechanism, the system can isolate the filter cylinder to be cleaned from the main flow path during backwashing and guide the sewage to flow out from other filter cylinders. At the same time, the sewage generated during the backwashing process is treated by the waste liquid treatment mechanism and then discharged back into the filter tank again, realizing the filtration operation without stopping the machine, without interrupting the flow, and saving water. This design not only improves the operation efficiency of the system but also significantly reduces the treatment delay and cost increase caused by shutdown;

[0023] 2. In the present invention, the system is equipped with a monitoring box. The front-end data acquisition unit can collect the weight change values of each pollution interception filter cylinder in real time and transmit the data to the comparison and control unit. The comparison and control unit automatically analyzes the data according to the preset threshold. When it is found that the weight change value of a certain pollution interception filter cylinder exceeds the set threshold, it will automatically control the corresponding pneumatic pulse generator to work and start the backwashing program. This automated monitoring and control design reduces the frequency and difficulty of manual intervention, making the system operation more intelligent and convenient. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the overall structure of the automatic pulse type backwashing filtration system of the present invention;

[0025] Figure 2 It is a schematic diagram of the installation structure of the first pollution interception filter cylinder in the filter tank of the present invention;

[0026] Figure 3Schematic diagram of the installation of the nozzle structure of the pneumatic pulse generator of the present invention in the first anti-blocking filter cylinder;

[0027] Figure 4 Schematic diagram of the connection structure between the side communication pipe of the guiding cylinder and the Y-shaped cylinder tank of the present invention;

[0028] Figure 5 Schematic diagram of the installation structure of the U-shaped pipe at the bottom of the guiding cylinder of the present invention;

[0029] Figure 6 Schematic diagram of the sectional structure of the Y-shaped cylinder tank of the present invention.

[0030] In the figure: 1. Filter tank; 2. Liquid inlet pipe; 3. Electric valve 1; 4. Liquid outlet pipe; 5. First anti-blocking filter cylinder; 6. Pneumatic pulse generator; 7. Air duct; 8. Nozzle; 9. Monitoring box; 10. Conversion liquid discharge mechanism; 101. Driving shaft; 102. Guiding cylinder; 103. U-shaped pipe; 104. Elastic plug cover; 105. Communication pipe; 11. Partition board; 12. Waste liquid treatment mechanism; 121. Y-shaped cylinder tank; 122. Second anti-blocking filter cylinder; 123. Piston rod; 13. Liquid control pipe; 14. Electric valve 2; 15. Electric valve 3. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figure 1-6 , the present invention provides a technical solution:

[0033] Embodiment 1: An automatic pulse type backwashing filtration system is an efficient and intelligent filtration device, mainly divided into filtration and monitoring components. Regarding the normal filtration stage, the liquid enters the filtration unit from the inlet, intercepts impurities such as solid particles and suspended matters through filtration media such as filter screens, filter elements, and filter bags, and the clean liquid is discharged from the outlet. Different from the backwashing stage, the commonly used disassembly and washing treatment is adopted. The control system starts a pulse generator such as a solenoid valve or a pneumatic device, instantly releases high-pressure water flow or gas, forms a reverse shock wave, and completes the cleaning of the filter cylinder after shutdown. However, the shutdown of the equipment will also cause a reduction in the overall sewage purification efficiency.

[0034] Therefore, a continuous-flow backwashing filtration system is provided, such as Figure 1As shown, the main body is divided into a filtering component and a monitoring component. The bottom of the filter tank 1 is connected to a liquid inlet pipe 2, and an electric valve 3 is installed on the liquid inlet pipe 2. The side wall is connected to a liquid outlet pipe 4, and the bottom inlet liquid and the side wall outlet liquid complete the sewage circulation in the filter tank 1. Figure 2 As shown, six dirt filter cartridges 5 are evenly arranged inside the filter tank 1 and extending to the tank top. The bottom of the dirt filter cartridge 5 is connected to the inner wall partition 11 of the filter tank 1. The sewage enters the dirt filter cartridge 5 along the partition 11, and then gradually reaches the position of the liquid outlet pipe 4 through the dirt filter cartridge 5, automatically completing the filtering and external discharge operation. This type of liquid circulation belongs to the normal filtering stage;

[0035] When the impurities adsorbed on the inner wall of the dirt filter cartridge 5 increase, the pressure difference on both sides of the filter medium gradually increases, and at the same time, the weight of the dirt filter cartridge 5 increases, and the backwash signal begins to be triggered to clean the inner wall of the dirt filter cartridge 5;

[0036] A monitoring box 9 is fixed on the top of the side wall of the filter tank 1. At the same time, a weighing sensor is set on the top of each filter cartridge 5 on the filter tank 1 side to monitor the weight values ​​of the six filter cartridges 5 in real time. As the dirt on the inner wall of the filter cartridge 5 accumulates, its own weight continues to increase. The weighing sensor sends the collected weight values ​​of each filter cartridge 5 to the monitoring box 9.

[0037] A front-end data acquisition unit and a comparison and control unit are arranged in the monitoring box 9. The front-end data acquisition unit is used to collect real-time weight values ​​on the six dirt filter cartridges 5, set a monitoring cycle, such as monitoring the weight values ​​on the six dirt filter cartridges 5 every 10 minutes, obtain the weight values ​​of the previous and next monitoring cycles on a single dirt filter cartridge 5, calculate the weight difference of the dirt filter cartridge 5, and send the collected weight difference values ​​of each dirt filter cartridge 5 within the monitoring cycle to the comparison and control unit for in-depth processing;

[0038] According to the obtained weight difference within the monitoring period of the dirt filter cartridge 5, the comparison control unit compares it with the set threshold of the dirt filter cartridge 5 stored and set by itself. When the weight difference within the monitoring period of the dirt filter cartridge 5 is greater than the set threshold of the dirt filter cartridge 5, it is determined that the impurities intercepted by the inner wall of the single dirt filter cartridge 5 at this time exceed the standard, and a backwashing operation is required to generate a corresponding backwashing signal. When the weight difference within the monitoring period of the dirt filter cartridge 5 is less than or equal to the set threshold of the dirt filter cartridge 5, no signal is generated;

[0039] A plurality of dirt filter cartridges are used in a 5-unit parallel structure, which work in turns during backwashing, and the system flow fluctuation is small. At the same time, unlike traditional pulse cleaning, the filter tank 1 is used to intercept the raw liquid for auxiliary cleaning, and no external independent water supply is required, and the water consumption is greatly reduced.

[0040] Example 2: Compared with the filter cartridge flushing taken during shutdown,Figure 3 and Figure 4 It can be understood that a motor is fixed at the top of the filter tank 1, and a conversion liquid discharge mechanism 10 is fixed on the output end of the motor. Among them, the drive shaft 101 in the conversion liquid discharge mechanism 10 is driven by the motor, and the guide cylinder 102 is fixed on the partition plate 11. The drive shaft 101 penetrates through the guide cylinder 102 and is connected to the U-shaped pipe 103 at its bottom, and an elastic plugging cover 104 is fixed at the end of the U-shaped pipe 103, which fits against the bottom of the partition plate 11;

[0041] As Figure 5 shown, under normal conditions, the elastic plugging cover 104 is in contact with the non-hole part at the bottom of the partition plate 11, and the sewage usually flows normally along the holes. When the drive shaft 101 drives the U-shaped pipe 103 to rotate, the elastic plugging cover 104 contacts the hole at the bottom of the single sewage interception filter cylinder 5 and is completely sealed. At this time, the filtered and unfiltered liquid at the top of the partition plate 11 will flow reversely along the U-shaped pipe 103, and the water flow starts to flow into the communication pipe 105 along the guide cylinder 102;

[0042] As Figure 4 shown, the communication pipe 105 is communicated with the waste liquid treatment mechanism 12 on the outer wall of the filter tank 1. If the single-side electric valve of the Y-shaped cylinder tank 121 is opened at this time, as Figure 6 shown, when the electric valve three 15 is opened, the water flow in the filter tank 1 continuously discharges from the liquid control pipe 13 of the electric valve three 15. Along with the discharge of the sewage in the single sewage interception filter cylinder 5, the remaining sewage interception filter cylinders 5 normally carry out the filtering work, which will not affect the normal operation of the entire filtering system. Compared with shutting down for the backwashing and cleaning of the filtering system, the overall sewage treatment efficiency is improved;

[0043] When the sewage in the single sewage interception filter cylinder 5 starts to be discharged reversely, in order to improve the cleaning effect of the inner wall of the overall single sewage interception filter cylinder 5, it is necessary to simultaneously control the air pulse generator 6 on the corresponding single sewage interception filter cylinder 5 to work. When the air pulse generator on the corresponding single sewage interception filter cylinder 5 is turned on, the nozzle 8 at the end of the air guide pipe 7, and the compressed air is instantly released into the liquid near the single sewage interception filter cylinder 5 through the nozzle 8, forming a dense bubble group. The bubbles rapidly expand in the liquid, generating local high-pressure shock waves and micro-jet flows, directly flushing the filter holes and removing the blocking particles. At the same time, the impact force of the bubbles is gentle, avoiding mechanical damage to the precision filter screen by high-pressure water. Since the bubbles move upward, a liquid vortex is caused during the rising process, enhancing the shear peeling ability of the impurities on the filter screen surface. At this time, the outer purified water flow starts to flow reversely downward from the inner wall of the flushed single sewage interception filter cylinder 5 and enters the Y-shaped cylinder tank 121 together with the peeled impurities, avoiding excessive liquid waste problems during backwashing;

[0044] As Figure 6As shown, the middle part of the entire Y-shaped cylinder tank 121 is connected to the guide cylinder 102. The liquid mixed with a large amount of impurities enters the Y-shaped cylinder tank 121 and first contacts the second pollution interception filter cylinder 122 arranged on one side. Through the setting of the second pollution interception filter cylinder 122, the fixed original liquid is intercepted and recycled for backwashing, avoiding a large amount of waste of the original liquid during backwashing. After being intercepted and treated by the second pollution interception filter cylinder 122, the purified original liquid returns to the filter tank 1 through the liquid control pipe 13. The sewage treatment carried out by the second pollution interception filter cylinder 122 has a large pollution content. Subsequently, for the backwashing sewage treatment on the first pollution interception filter cylinder 5, it is necessary to switch the flow direction of the externally discharged sewage in the Y-shaped cylinder tank 121;

[0045] A piston rod 123 that can slide is arranged in the middle of the Y-shaped cylinder tank 121. As Figure 6 shown, if the piston rod 123 is located on the left side at this time, the original liquid sewage is discharged through the second pollution interception filter cylinder 122 on the right side. At the same time, the second electric valve 14 on the right liquid control pipe 13 is opened. If the flow direction of the entire original liquid purification is controlled and the second pollution interception filter cylinder 122 on the other side is manually cleaned, only need to push the piston rod 123 on one side, so that the original liquid starts to move to the left, and at the same time open the third electric valve 15 on the left liquid control pipe 13. At this time, the second pollution interception filter cylinder 122 on the right side is in a static state. Without affecting the normal purification of the original liquid, the second pollution interception filter cylinder 122 on the right side can be taken out for manual flushing treatment to provide continuous purification conditions for the subsequent sewage;

[0046] By switching the piston rod 123 left and right to restrict the sewage discharge direction and purify the backwashing original liquid of the filter tank 1, the pulse cleaning time is short, avoiding the problem of waste of impurities and the original liquid caused by using the original liquid to clean the inner wall of the first pollution interception filter cylinder 5.

[0047] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the relevant technical field can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. An automatic pulse backwashing filtration system, comprising a filter tank (1), characterized in that: The bottom of the filter tank (1) is connected to a liquid inlet pipe (2), an electric valve (3) is installed on the liquid inlet pipe (2), the side wall of the filter tank (1) is connected to a liquid outlet pipe (4), a partition (11) is fixed to the inner wall of the filter tank (1) by welding, a dirt filter cartridge (5) is evenly fixed between the filter tank (1) and the partition (11) by bolts, and the dirt filter cartridge (5) is located at the top of the filter tank (1) and is connected to and fixed with a pneumatic pulse generator (6); The pneumatic pulse generator (6) is located inside the dirt filter cartridge (5) and is connected to and fixed with an air guide pipe (7), the end of the air guide pipe (7) is connected to and fixed with a nozzle (8), and a monitoring box (9) is fixed to the outer wall bracket of the filter tank (1) by bolts; The monitoring box (9) comprises a front-end data acquisition unit and a comparison and control unit, wherein the front-end data acquisition unit is used to collect the weight change value of each dirt filter cartridge (5) within a monitoring period, and the comparison and control unit is used to obtain the weight change value of each dirt filter cartridge (5) and compare it with a set threshold value to generate a backwashing signal to control the opening and closing of the valve.

2. The automatic pulse backwashing filtration system according to claim 1, characterized in that: A conversion drainage mechanism (10) is installed on the top of the filter tank (1), and the conversion drainage mechanism (10) comprises a drive shaft (101), a guide cylinder (102) and a U-shaped tube (103). The drive shaft (101) is fixed to the output end of the motor installed on the top of the filter tank (1). The guide cylinder (102) is fixedly connected to the partition (11) in the filter tank (1). The bottom of the guide cylinder (102) is movably connected to the U-shaped tube (103). One end of the drive shaft (101) passes through the filter tank (1) and the guide cylinder (102) respectively and is connected to the U-shaped tube (103). An elastic plug cover (104) is installed on the other side of the U-shaped tube (103). The guide cylinder (102) is connected to a connecting tube (105) on the side wall located on the top of the partition (11).

3. The automatic pulse backwashing filtration system according to claim 2 is characterized in that: A waste liquid treatment mechanism (12) is fixed on the side wall of the filter tank (1) via a bracket, and the waste liquid treatment mechanism (12) comprises a Y-shaped barrel tank (121) and a second dirt filter cartridge (122). The Y-shaped barrel tank (121) is fixedly connected to the side wall bracket of the filter tank (1), and a second dirt filter cartridge (122) is symmetrically installed in the Y-shaped barrel tank (121).

4. The automatic pulse backwashing filtration system according to claim 3 is characterized in that: One end of the connecting pipe (105) passes through the filter tank (1) and is connected to the Y-shaped cylindrical tank (121). The waste liquid treatment mechanism (12) also includes a piston rod (123). One end of the piston rod (123) passes through the Y-shaped cylindrical tank (121) and is slidably connected to the tank body.

5. The automatic pulse backwashing filtration system according to claim 4 is characterized in that: The two sides of the Y-shaped cylinder tank (121) are symmetrically connected with liquid control pipes (13), one side of the liquid control pipe (13) is equipped with an electric valve 2 (14), and the other side of the liquid control pipe (13) is equipped with an electric valve 3 (15).

6. The automatic pulse backwashing filtration system according to claim 5, characterized in that: Weighing sensors are evenly installed on the top of the filter tank (1) and on one side of the trash filter cartridge (5). The weighing sensors monitor the weight change of each trash filter cartridge (5) and send the generated signal to the monitoring box (9).

7. The automatic pulse backwashing filtration system according to claim 6, characterized in that: The filtering method of the automatic pulse backwashing filter system is: The multi-filter cartridge online filtration monitoring follows the operation of sewage entering through the liquid inlet pipe (2), filtering through the sewage filter cartridge (5) and discharging through the liquid outlet pipe (4). The sewage first enters the sewage filter cartridge (5) through the holes on the bottom baffle (11) of the filter tank (1), diffuses from the inside to the outside, and the liquid level gradually rises above the liquid outlet pipe (4). After being intercepted by the sewage filter cartridge (5), the sewage remains on the inner wall of the sewage filter cartridge (5), completing the forward filtration operation. As dirt accumulates on the inner wall of the dirt filter cartridge (5), its own mass increases. The weighing sensor installed on the top of the filter tank (1) sends the weight values ​​obtained on each dirt filter cartridge (5) to the monitoring box (9). The front-end data acquisition unit in the monitoring box (9) calculates the difference between the weight values ​​of the dirt filter cartridge (5) obtained during the monitoring period according to the set monitoring period, and sends the weight change value of the dirt filter cartridge (5) to the comparison control unit for threshold comparison. When the weight change value of the dirt filter cartridge (5) is greater than the set threshold, a backwashing signal is generated to control the pneumatic pulse generator (6) on the corresponding dirt filter cartridge (5) to work. At the same time, the drive shaft (101) drives the elastic blocking cover (104) on the U-shaped tube (103) to move to the bottom of the corresponding overloaded dirt filter cartridge (5), the electric valve (14) on the liquid control pipe (13) on the side of the Y-shaped cylinder tank (121) is opened, the corresponding pneumatic pulse transmitter on the dirt filter cartridge (5) is opened, the nozzle (8) at the end of the air guide pipe (7) is opened, and the compressed air is instantly released into the liquid near the dirt filter cartridge (5) through the nozzle (8), forming a dense bubble group. The bubbles expand rapidly in the liquid, generating local high-pressure shock waves and microjets, directly flushing the filter holes, removing the blocked particles, and at the same time, the cleaned sewage flows into the Y-shaped cylinder tank (121) along the connecting pipe (105), is filtered by the dirt filter cartridge (122), and is discharged back into the filter tank (1), completing the liquid filtering operation without stopping the machine and continuing the flow.

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