A backflush filter

Abstract

The utility model discloses a backwash filter, including filter jar body and setting at the water inlet of filter jar body right end center upper side, the water outlet is provided with at filter jar body right end center downside, the water inlet and water outlet are close to the top and bottom of filter jar body respectively, the differential pressure switch is provided with at filter jar body left end center, the filter jar body inside is provided with the cylinder type filter screen, can with the original structure cooperation and promote cylinder type filter screen cleaning effect through the filter jar body additional novel efficiency decontamination device, reduce the block, prolong filter screen life, guarantee the filtration efficiency and reduce maintenance cost, the device is divided to the gas branch pipe of sending gas by ring type gas collector, is accurately spouted to the filter screen outer wall through the jet pipe head, the stubborn stain and small impurity that the stubborn stain and small impurity that traditional mechanical decontamination missed are cleaned up through the jet pipe head, realizes all -round deep -cleaning, avoids the filtration precision decline.

Description

Technical Field

[0001] This utility model belongs to the technical field of fluid filtration and purification, and specifically relates to a backwash filter. Background Technology

[0002] Backwash filters, as a highly efficient water purification device, are widely used in industrial circulating water, municipal water supply, agricultural irrigation, and sewage treatment. Their core principle is to intercept suspended solids, particulate matter, and other impurities in the water using filter elements such as cylindrical screens, reducing water turbidity and ensuring the stable operation of subsequent pipelines and equipment. Simultaneously, the equipment is equipped with a backwash cleaning system that periodically removes accumulated impurities from the filter screen, preventing clogging and subsequent decrease in filtration efficiency. This allows for long-term continuous filtration operations, making it an indispensable key device in modern fluid processing systems.

[0003] However, traditional backwash filters mostly rely on mechanical cleaning (such as brush wiping) or water backwashing. The mechanical cleaning components usually only wipe the inside of the filter screen and cannot reach the outside of the filter screen. Impurities in the water are mainly intercepted on the outside of the filter screen, and long-term accumulation can easily form a stubborn dirt layer, or even block the filter screen pores. Even if some equipment uses water backwashing, uneven flushing force and many dead corners can easily lead to local impurities remaining on the filter screen, which will continuously affect the filtration accuracy and increase the operating resistance of the equipment. Utility Model Content

[0004] The purpose of this utility model is to provide a backwash filter to solve the problems mentioned in the background art. Traditional backwash filters rely on mechanical cleaning or water backwashing. Mechanical cleaning only reaches the inside of the filter screen and is difficult to remove the main impurities on the outside, which easily accumulates dirt and clogs the holes. Water backwashing also often leaves impurities due to uneven flushing force and dead corners, which affects the filtration accuracy and increases the operating resistance.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a backwash filter, comprising a filter tank and an inlet located on the upper side of the center of the right end of the filter tank, an outlet located on the lower side of the center of the right end of the filter tank, the inlet and outlet being located near the top and bottom of the filter tank respectively, a differential pressure switch located at the center of the left end of the filter tank, a cylindrical filter screen being installed inside the filter tank, and ring-shaped fixing plates being fixed at both ends of the cylindrical filter screen, with the two ring-shaped fixing plates respectively sealing and fixing to the inner wall of the bottom end of the filter tank and the upper circular inner wall of the center, and an efficiency-enhancing decontamination device being sleeved and fixed to the outside of the bottom end of the filter tank.

[0006] Preferably, the enhanced decontamination device includes a ring-shaped fixing frame, a ring-shaped air collecting pipe, and air supply branch pipes. The ring-shaped fixing frame is sleeved and fixed on the circular outer wall at the bottom of the filter tank. The ring-shaped air collecting pipe is fixed at the top of the ring-shaped fixing frame and is also sleeved on the outside of the filter tank. Multiple air supply branch pipes are equidistantly arranged at the top of the ring-shaped air collecting pipe.

[0007] Preferably, the annular air collecting pipe is internally connected to multiple air supply branches, all of which are vertically arranged upwards and are arranged in a circular pattern around the outer wall of the filter tank. The arrangement of the multiple air supply branches bypasses the water inlet, water outlet, and differential pressure switch, i.e., the water inlet, water outlet, and differential pressure switch are located between two adjacent air supply branches.

[0008] Preferably, the enhanced decontamination device further includes jet nozzles and anti-reverse jet nozzles. Multiple jet nozzles are equidistantly arranged on the outer wall of the multiple air supply pipes near the outer wall of the filter tank. The multiple jet nozzles are arranged equidistantly from bottom to top and penetrate the outer wall of the filter tank. The connection between the multiple jet nozzles and the filter tank is sealed with rubber sleeves and sealant. One end of the air outlet of each of the multiple jet nozzles is connected to an anti-reverse jet nozzle, and the multiple anti-reverse jet nozzles are located between the circular inner wall of the filter tank and the circular outer wall of the cylindrical filter screen.

[0009] Preferably, the enhanced decontamination device further includes an external pipe connector, which is fixed to the top of the annular gas collection pipe and connected to an external high-pressure gas supply pipe. The gas delivery branch pipe is at the same height as the cylindrical filter screen, and the jet direction of the multiple anti-reverse jet nozzles is all aligned with the center of the cylindrical filter screen.

[0010] Preferably, both the inlet and outlet are provided with external flanges on the right side, and both the inlet and outlet are connected to the inside of the filter tank. The inlet is located above the right side of the annular fixing plate at the top of the cylindrical filter screen.

[0011] Preferably, a drain valve is provided at the center of the bottom of the filter tank, the inlet of the drain valve is connected to the inside of the filter tank, the right end of the drain valve is provided with an outlet, and a drain pipe is connected to the outlet of the drain valve.

[0012] Preferably, a sealing flange is provided on the top of the filter tank, and an end cap is provided on the top of the filter tank and the sealing flange. The end cap is fixedly connected to the sealing flange by multiple screws. A speed reducer is provided at the center of the top of the end cap, and a decontamination motor is provided on the top of the speed reducer. The decontamination motor and the differential pressure switch are both electrically connected to an external control power supply through wires.

[0013] Preferably, a decontamination shaft is vertically arranged inside the center of the filter tank. The top end of the decontamination shaft is connected to the output shaft of the reducer via a coupling. The bottom end of the decontamination shaft is located above the drain port at the center of the bottom of the filter tank. Fixing sleeves are fitted and fixed on the upper side of the center of the decontamination shaft and the outside of the bottom end.

[0014] Preferably, both ends of the two fixed sleeves are connected to U-shaped cleaning brackets, and the outer walls of the two U-shaped cleaning brackets are densely covered with cleaning bristles, which are in close contact with the inner wall of the cylindrical filter screen.

[0015] Compared with the prior art, the present invention provides a backwash filter with the following advantages:

[0016] This invention adds a novel enhanced cleaning device to the bottom and top of the filter tank. This device works synergistically with the original filtration and cleaning structure of the filter to significantly improve the cleaning effect on the cylindrical filter screen, effectively reduce the probability of filter screen clogging, extend the service life of the filter screen, and at the same time ensure the stability of the overall filtration efficiency of the filter, reducing the frequency and cost of equipment maintenance. The enhanced cleaning device distributes external high-pressure gas evenly to multiple air delivery pipes through a ring-shaped air collection pipe. Then, the air jet head and anti-reverse air jet head on each air delivery pipe precisely spray air onto the outer wall of the cylindrical filter screen. The high-pressure gas can form a strong impact on the impurities and dirt attached to the outer wall of the cylindrical filter screen. In particular, it can clean stubborn stains or small impurities in the filter screen pores that may be missed by traditional mechanical cleaning (such as brush wiping), achieving all-round and deep cleaning of the filter screen and avoiding the problem of decreased filtration accuracy caused by the accumulation of impurities.

[0017] Furthermore, the anti-reverse jet head in the device is in a closed state when not spraying, which can effectively prevent water or impurities inside the filter tank from flowing back into the jet head, air supply pipe, and ring-shaped air collection pipe, preventing air blockage or component corrosion damage, ensuring smooth airflow for the next jet, and guaranteeing long-term stable operation of the enhanced cleaning device without the need for frequent cleaning and maintenance of the air path. When the enhanced cleaning device is operating for jet cleaning, the inlet or outlet needs to be opened to allow gas to be discharged. This design can avoid excessive pressure generated inside the tank due to jetting, preventing equipment damage or sealing failure due to pressure overload. At the same time, it allows impurities washed off during the jetting process to be discharged with water or airflow through the inlet or outlet (or to achieve centralized sewage discharge in conjunction with the drain valve), further improving cleaning efficiency and ensuring that the entire cleaning process is carried out safely and orderly. Attached Figure Description

[0018] Figure 1 This is a front view three-dimensional structural diagram of the external structure of a backwash filter according to the present invention.

[0019] Figure 2This is a schematic diagram of the external front view of a backwash filter according to the present invention.

[0020] Figure 3 This is a front sectional three-dimensional structural diagram of the internal structure of a backwash filter according to the present invention.

[0021] Figure 4 This is a front-view three-dimensional structural diagram of the efficiency-enhancing decontamination device of this utility model.

[0022] In the diagram: 1. End cap; 2. Inlet; 3. Outlet; 4. Drain pipe; 5. Enhanced cleaning device; 6. Differential pressure switch; 7. Filter tank; 8. Sealing flange; 9. Reducer; 10. Cleaning motor; 11. Drain valve; 12. Fixing sleeve; 13. Cleaning shaft; 14. U-shaped cleaning bracket; 15. Cleaning brush bristles; 16. Tubular filter screen; 17. Ring-type fixing plate; 18. Ring-type fixing frame; 19. Ring-type air collection pipe; 20. External pipe connector; 21. Air supply branch pipe; 22. Air jet head; 23. Check jet head. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] This utility model provides, for example Figures 1-4The backwash filter shown achieves high-efficiency filtration and deep cleaning through a scientific structural design and collaborative working mechanism. Specifically, the core carrier of the filter is the filter tank 7. The filter tank 7 adopts an upper and lower split design at the center of the right end, with an inlet 2 on the upper side and an outlet 3 on the lower side. These are located near the top and bottom of the tank, respectively, and both are equipped with external flanges on their right ends for quick connection to external pipelines, ensuring the stability of water delivery. Both the inlet 2 and outlet 3 are connected to the inside of the tank, and the inlet 2 is precisely aligned with the upper right side of the annular fixing plate 17 at the top of the cylindrical filter screen 16. This position guides the water to be filtered from the outside to the inside of the filter screen. When water enters the tank from the inlet 2, it must pass through the cylindrical filter screen 16. Suspended solids, particulate matter, and other impurities in the water are intercepted by the cylindrical filter screen 16, and the filtered clean water passes through the cylindrical filter screen 16, ultimately... The water is discharged from the bottom outlet 3, achieving basic filtration. The cylindrical filter screen 16, as the core filtration element, is fixed with ring-shaped fixing plates 17 at both its upper and lower ends. The two sealing plates are respectively sealed and fixed to the inner wall of the bottom end and the upper circular inner wall of the center of the filter tank 7. This sealing and fixing method not only ensures the stability of the cylindrical filter screen 16 in the tank and avoids the filter screen from shifting due to water flow impact, but also completely separates the water inside and outside the cylindrical filter screen 16, preventing unfiltered water from mixing with filtered water and ensuring filtration accuracy. In order to monitor the filtration status in real time, a differential pressure switch 6 is set at the center of the left end of the filter tank 7. It judges the degree of blockage of the cylindrical filter screen 16 by detecting the pressure difference change inside and outside the cylindrical filter screen 16. When too many impurities accumulate inside the cylindrical filter screen 16, the pressure difference inside and outside the cylindrical filter screen 16 will exceed the preset value. At this time, the differential pressure switch 6 will send a signal to the external control power supply to trigger the subsequent cleaning process and realize intelligent operation and maintenance.

[0025] like Figure 1 , Figure 2 and Figure 3As shown, to address the fine impurities that may adhere to the inner side of the cylindrical filter screen 16, the tank is equipped with a mechanical decontamination assembly, specifically including a decontamination motor 10, a reducer 9, a decontamination shaft 13, a fixing sleeve 12, a U-shaped decontamination bracket 14, and decontamination brushes 15. The filter tank 7 has a sealing flange 8 on its top exterior, with an end cap 1 fixed to the top of the flange by screws. A reducer 9 is installed at the center of the top of the end cap 1, and the reducer 9 is connected to the decontamination motor 10. The decontamination motor 10 and the differential pressure switch 6 are both electrically connected to an external control power supply via wires, forming a linkage control logic. A decontamination shaft 13 is vertically installed at the center of the filter tank 7, with its top connected to the output shaft of the reducer 9 via a coupling. Its bottom extends above the drain port at the center of the bottom of the tank. Fixing sleeves 12 are fitted onto the upper side and the outer side of the bottom of the decontamination shaft 13. The two fixing sleeves 12 are positioned on the left and right sides of the shaft. A U-shaped cleaning bracket 14 is connected to each of the right ends. The outer wall of the U-shaped bracket is densely covered with cleaning bristles 15, and the bristles are in close contact with the inner wall of the cylindrical filter screen 16. When the differential pressure switch 6 triggers the cleaning signal, the cleaning motor 10 starts and drives the cleaning shaft 13 to rotate at low speed through the reducer 9. The shaft drives the fixed sleeve 12 and the U-shaped cleaning bracket 14 to rotate synchronously, so that the cleaning bristles 15 slide along the inner wall of the cylindrical filter screen 16 and wipe off the impurities attached to the inner side of the cylindrical filter screen 16. The detached impurities are deposited downward under the action of gravity, preparing for subsequent sewage discharge. A sewage discharge valve 11 is set at the center of the bottom of the filter tank 7. Its inlet is connected to the inside of the tank and its outlet is connected to the sewage discharge pipe 4. When the mechanical cleaning is completed, the sewage discharge valve 11 is opened, and the impurities deposited at the bottom of the tank will be discharged from the sewage discharge port along with some water, achieving preliminary cleaning and ensuring the flow of the cylindrical filter screen 16.

[0026] like Figure 1 and Figure 4As shown, to further enhance the cleaning effect of the cylindrical filter screen 16, an efficiency-enhancing decontamination device 5 is fixedly fitted onto the bottom of the filter tank 7. This device works in conjunction with the mechanical decontamination components to form a dual internal and external cleaning mechanism. The efficiency-enhancing decontamination device 5 includes a ring-shaped fixing frame 18, a ring-shaped air collecting pipe 19, an air supply branch pipe 21, an air jet head 22, a backflow preventer air jet head 23, and an external pipe head 20. The positional relationship of each component is fully adapted to the original structure of the tank to avoid functional interference. The ring-shaped fixing frame 18 is fitted and fixed on the circular outer wall at the bottom of the filter tank 7, providing stable support for the entire device. The top of the ring-shaped air collecting pipe 19 is fixed, and the air collecting pipe is also fitted onto the outside of the tank to evenly collect high-pressure gas. Multiple air supply branch pipes 21 are equidistantly arranged at the top of the ring-shaped air collecting pipe 19. The air supply branch pipes 21 are all vertically arranged upwards and are arranged in a circle around the outside of the tank. The key is that the arrangement of the air supply branch pipes 21 precisely bypasses the water inlet. 2. The outlet 3 and differential pressure switch 6 are located between two adjacent air supply pipes 21, which does not affect the original pipeline connection and pressure monitoring, and ensures that the gas delivery covers the circumference of the filter tank 7. The air supply pipe 21 is at the same height as the cylindrical filter screen 16, and multiple air jet heads 22 are evenly arranged from bottom to top on the outer wall of the filter tank 7. The air jet heads 22 penetrate the outer wall of the tank, and the connection with the tank is sealed with rubber sleeves and sealant to prevent water leakage. One end of the air outlet of the air jet head 22 is connected to the check jet head 23, and the check jet head 23 is located between the circular inner wall of the filter tank 7 and the circular outer wall of the cylindrical filter screen 16. It can directly spray air onto the outer wall of the cylindrical filter screen 16 to specifically clean the stubborn impurities accumulated on the outside. In addition, the top of the annular air collecting pipe 19 is fixed with an external pipe head 20, which is connected to the external high-pressure gas supply pipeline to provide a stable high-pressure gas source for the device.

[0027] like Figure 1 and Figure 4As shown, the check jet head 23 is the core component of the enhanced cleaning device 5. It is responsible for high-pressure jet cleaning and prevents water from back-contaminating the air path. Its specific structure and working principle are as follows: The check jet head 23 is mainly composed of a ball joint, a spring-loaded joint, a valve seat, a check valve core, a pressure spring, and a detachable nozzle. These components work together to realize the functions of opening and closing the jet. When cleaning is required, external high-pressure gas enters the annular gas collection pipe 19 through the external pipe joint 20, and is then distributed to each gas delivery pipe 21, finally reaching the jet head 22 and the check jet head 23. At this time, the pressure of the high-pressure gas is greater than the pressure of the water inside the tank. The pressure difference pushes the check valve core downward, causing it to press against the spring. The head separates, forming a gas flow gap. High-pressure gas flows through the gap, passes through the internal flow channel, and reaches the detachable nozzle. Finally, it is precisely sprayed onto the outer wall of the cylindrical filter screen 16, creating a strong impact on the impurities accumulated on the outside of the filter screen. This washes away stubborn stains that are difficult to clean by mechanical cleaning and small impurities in the filter screen pores. When the gas is not sprayed, the high-pressure gas supply stops. At this time, the water pressure inside the tank is greater than the gas pressure. The compression spring resets and pushes the check valve core upward. The valve core tightly seals the central hole, completely preventing water or impurities inside the tank from entering the jet head 22, the gas supply branch pipe 21, and the ring-shaped gas collection pipe 19 in reverse. This avoids gas path blockage or component corrosion, ensuring long-term stable operation of the device without the need for frequent gas path cleaning.

[0028] like Figure 1 and Figure 4 As shown, the operation of the enhanced decontamination device 5 needs to be coordinated with the original inlet and outlet of the tank to form a complete process from air jetting to exhausting to sewage discharge. During operation, the inlet 2 or outlet 3 and the drain valve 11 need to be opened to provide an exhaust channel for the gas in the filter tank 7 (the inlet 2 and outlet 3 can provide an exhaust channel for the gas, and the drain valve 11 provides an exhaust channel for the impurities). When the high-pressure gas is sprayed onto the outer wall of the cylindrical filter screen 16, it will drive some water to flow. The gas and the impurities washed off can be discharged with the water from the opened drain valve 11, which avoids excessive pressure generated in the tank due to air jetting. While preventing equipment damage from force, this device ensures that impurities are promptly removed from the cartridge filter 16 and filter tank 7, improving cleaning efficiency. The core advantage of this device lies in its ability to overcome the limitation of traditional mechanical decontamination, which can only clean the inside of the filter screen. By impacting from the outside with high-pressure gas, it achieves dual cleaning of the cartridge filter 16, significantly reducing the probability of clogging and extending its service life. At the same time, the anti-reverse structure and sealing design ensure the reliability of the device, while the adaptability design ensures seamless integration with the original structure without affecting the overall operational stability of the filter.

[0029] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the complete backwashing process of this backwash filter is based on the logic of differential pressure monitoring, mechanical decontamination, gas-enhanced cleaning, and sewage discharge. Each link works together to achieve efficient cleaning. When the accumulation of impurities on the cylindrical filter screen 16 causes the internal and external pressure difference to exceed the preset value, the differential pressure switch 6 sends a signal to start the cleaning process. The decontamination motor 10 starts and drives the U-shaped bracket and brush bristles to rotate through the shaft, wiping the inner side of the filter screen and removing the impurities. External high-pressure gas enters the enhanced decontamination device 5 through the external pipe connector 20, and is distributed to the check jet head 23 through the gas collection pipe and the gas delivery pipe 21. The jet head opens and sprays air onto the outer wall of the filter screen, washing away the impurities. For stubborn impurities on the outside, simultaneously open inlet 2 or outlet 3 to ensure smooth gas discharge. Open drain valve 11, and all impurities deposited at the bottom of the tank will be discharged with the water from drain pipe 4. After cleaning, all components will be reset, and the filter will resume normal filtration. The advantage of this collaborative process is that it cleans more thoroughly, can clean impurities inside and outside the filter screen at the same time, has a high degree of intelligence, is automatically triggered based on pressure difference, does not require frequent manual intervention, operates stably, and has a reasonable design for the position of each component and reliable sealing to avoid leakage and functional interference. It can ensure filtration accuracy and efficiency for a long time and is suitable for various industrial and municipal scenarios that require high-precision filtration.

[0030] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A backwash filter, comprising a filter tank (7) and an inlet (2) disposed on the upper side of the center of the right end of the filter tank (7), an outlet (3) disposed on the lower side of the center of the right end of the filter tank (7), the inlet (2) and the outlet (3) being located near the top and bottom of the filter tank (7) respectively, a differential pressure switch (6) disposed at the center of the left end of the filter tank (7), a cylindrical filter screen (16) disposed inside the filter tank (7), and annular fixing plates (17) fixed at both the upper and lower ends of the cylindrical filter screen (16), the two annular fixing plates (17) being respectively sealed and fixed on the inner wall of the bottom end and the upper circular inner wall of the center of the filter tank (7), characterized in that: The filter tank (7) is fitted with an enhanced decontamination device (5) on the outside of the bottom end; The enhanced cleaning device (5) includes a ring-shaped fixing frame (18), a ring-shaped air collecting pipe (19), and an air supply branch pipe (21). The ring-shaped fixing frame (18) is sleeved and fixed on the circular outer wall at the bottom of the filter tank (7). The ring-shaped fixing frame (18) is fixed at the top of the ring-shaped fixing frame (18), and the ring-shaped air collecting pipe (19) is also sleeved on the outside of the filter tank (7). Multiple air supply branch pipes (21) are equidistantly arranged at the top of the ring-shaped air collecting pipe (19).

2. The backwash filter according to claim 1, characterized in that: The annular gas collecting pipe (19) is internally connected to multiple gas supply pipes (21). The multiple gas supply pipes (21) are all vertically arranged upwards, and the multiple gas supply pipes (21) are arranged in a circle and surround the outer wall of the filter tank (7). The arrangement of the multiple gas supply pipes (21) bypasses the water inlet (2), the water outlet (3), and the differential pressure switch (6). That is, the water inlet (2), the water outlet (3), and the differential pressure switch (6) are located between two adjacent gas supply pipes (21).

3. A backwash filter according to claim 2, characterized in that: The enhanced cleaning device (5) also includes a jet nozzle (22) and a check jet nozzle (23). Multiple jet nozzles (22) are equidistantly arranged on the outer wall of the multiple air supply pipes (21) near the outer wall of the filter tank (7). The multiple jet nozzles (22) are arranged equidistantly from bottom to top, and the multiple jet nozzles (22) penetrate the outer wall of the filter tank (7). The connection between the multiple jet nozzles (22) and the filter tank (7) is sealed with rubber sleeves and sealant. One end of the air outlet of the multiple jet nozzles (22) is connected to a check jet nozzle (23), and the multiple check jet nozzles (23) are located between the circular inner wall of the filter tank (7) and the circular outer wall of the cylindrical filter screen (16).

4. A backwash filter according to claim 3, characterized in that: The enhanced cleaning device (5) also includes an external pipe head (20), which is fixed at the top of the annular gas collection pipe (19) and connected to an external high-pressure gas supply pipe. The gas delivery pipe (21) is at the same height as the cylindrical filter screen (16), and the jet direction of the multiple anti-reverse jet heads (23) is aligned with the center of the cylindrical filter screen (16).

5. A backwash filter according to claim 1, characterized in that: Both the inlet (2) and outlet (3) are provided with external flanges on the right side. Both the inlet (2) and outlet (3) are connected to the inside of the filter tank (7), and the inlet (2) is located above the right side of the ring-shaped fixed sealing plate (17) at the top of the cylindrical filter screen (16).

6. A backwash filter according to claim 5, characterized in that: A drain valve (11) is provided at the center of the bottom of the filter tank (7). The inlet of the drain valve (11) is connected to the inside of the filter tank (7). The drain valve (11) has an outlet at the right end, and a drain pipe (4) is connected to the outlet of the drain valve (11).

7. A backwash filter according to claim 6, characterized in that: The filter tank (7) is provided with a sealing flange (8) on the outside of the top. The filter tank (7) and the sealing flange (8) are provided with an end cap (1), and the end cap (1) is fixedly connected to the sealing flange (8) by multiple screws. A speed reducer (9) is provided at the center of the top of the end cap (1), and a decontamination motor (10) is provided at the top of the speed reducer (9). The decontamination motor (10) and the differential pressure switch (6) are both electrically connected to an external control power supply through wires.

8. A backwash filter according to claim 7, characterized in that: A cleaning shaft (13) is vertically installed inside the center of the filter tank (7). The top end of the cleaning shaft (13) is connected to the output shaft of the reducer (9) through a coupling. The bottom end of the cleaning shaft (13) is located above the drain port at the center of the bottom of the filter tank (7). Fixing sleeves (12) are fitted and fixed on the upper side and the bottom outside of the center of the cleaning shaft (13).

9. A backwash filter according to claim 8, characterized in that: Both ends of the two fixed sleeves (12) are connected to U-shaped cleaning brackets (14). The outer walls of the two U-shaped cleaning brackets (14) are densely covered with cleaning bristles (15), and the cleaning bristles (15) are tightly attached to the inner wall of the cylindrical filter screen (16).

Images