A backwashing screen filter based on micro-nano bubble reinforced filtration

Abstract

The application discloses a backwashing screen filter based on micro-nano bubble reinforced filtration, and belongs to the field of filtration devices in agriculture, which comprises a filter shell with a water outlet, a first inlet, a second inlet and a blowdown outlet; a filter screen that separates the internal space of the filter shell into a filter screen inside filtering area and a filter screen outside water outlet area; a filtration process water inlet pipeline and a backwashing process water inlet pipeline, the first end of the filtration process water inlet pipeline is connected with the first inlet, the first end of the backwashing process water inlet pipeline is connected with the second inlet, the second end of the filtration process water inlet pipeline and the second end of the backwashing process water inlet pipeline are connected with a water inlet three-phase valve, and the third interface of the water inlet three-phase valve is a water inlet; and a micro-nano bubble generator that introduces gas into the water inlet area of the filter shell and forms a gas-liquid mixed flow rich in micro-nano bubbles. The application can effectively improve the filtration performance, self-cleaning capacity and operation stability of the filter.

Description

Technical Field

[0001] This invention pertains to filtration devices in the agricultural field, and more specifically relates to a backwashing mesh filter based on micro-nano bubble enhanced filtration. Background Technology

[0002] Mesh filters are widely used in agricultural irrigation, industrial circulating water treatment, landscape water treatment, and pre-treatment processes. They primarily use a filter screen to trap suspended particles, silt, and organic impurities in the water. Existing mesh filters typically rely on the filter screen itself for mechanical filtration, and remove adhering dirt through backwashing when the screen becomes clogged.

[0003] In existing technologies, common mesh filters allow water to simply pass through the filter screen during normal filtration, causing impurities to accumulate on the screen surface and form a fouling layer. As operating time increases, this fouling layer gradually compacts, leading to increased pressure differential, decreased flow rate, and increased backwashing frequency. While some filters are equipped with steel brushes or backwash jet structures, they primarily rely on passive cleaning after clogging has occurred, failing to effectively reduce dirt adhesion and deposition during normal filtration.

[0004] In addition, existing backwashing structures usually rely on a single reverse high-pressure water flow for flushing. For dirt layers that are highly adhesive, easily clump or compacted, the flushing effect is limited, and there are still problems such as incomplete dirt removal, repeated local clogging of the filter screen, and insufficient equipment operation stability.

[0005] Therefore, there is an urgent need for a mesh filter that can reduce the tendency of filter screen to adhere to dirt during the normal filtration stage and further enhance the dirt removal effect during the backwashing stage, so as to improve filtration efficiency and self-cleaning ability. Summary of the Invention

[0006] This invention aims to provide a mesh filter that can reduce the tendency of filter screen fouling during the normal filtration stage and further enhance the fouling removal effect during the backwashing stage. To achieve the above objective, this invention adopts the following technical solution: A backwashing mesh filter based on micro / nano bubble enhanced filtration, comprising: A filter housing having a water outlet, a first inlet, a second inlet, and a drain outlet; A filter screen is disposed inside the filter housing and divides the internal space of the filter housing into an inner filtration area and an outer water outlet area; wherein the water outlet and the second inlet are connected to the outer water outlet area, and the first inlet and the drain outlet are connected to the inner filtration area. The filter process inlet pipe and the backwash process inlet pipe are provided. The first end of the filter process inlet pipe is connected to the first inlet, and the first end of the backwash process inlet pipe is connected to the second inlet. The second ends of the filter process inlet pipe and the backwash process inlet pipe are connected to the inlet three-phase valve. The third interface of the inlet three-phase valve is the inlet. A micro-nano bubble generator, wherein the micro-nano bubble generator introduces gas into the water inlet area of ​​the filter housing and forms a gas-liquid mixture rich in micro-nano bubbles; In normal filtration conditions, raw water is introduced into the inner side of the filter screen through the inlet three-phase valve and the filtration process inlet pipe. In backwashing conditions, raw water is introduced into the outer side of the filter screen through the backwash process inlet pipe under the switching action of the inlet three-phase valve, so as to form a reverse flushing water flow on the filter screen.

[0007] Furthermore, the micro / nano bubble generator includes: A turbine, which is installed in the inlet pipe of the filtration process or in an adjacent flow channel, is driven to rotate by the kinetic energy of the inlet flow; An air intake valve, which is connected to an external air source or air, is used to introduce gas into the water intake area; The gas entering the intake valve forms micron-sized primary bubbles under the high-speed shearing and crushing action of the turbine, and mixes with the water flowing into the filter housing.

[0008] Furthermore, the micro / nano bubble generator also includes: The first-stage dissolved gas release head is located in the filtration zone inside the filter screen. It is set inside the filter housing near the water inlet area or at the front end of the inner side of the filter screen to refine and uniformly disperse the gas-liquid mixture after initial crushing by the turbine, so that the bubbles are further reduced and a more uniform gas-containing water flow is formed inside the filter screen. The secondary dissolved gas release head is located in the filtration zone inside the filter screen, and is set near the filter screen or distributed along the filter screen axis. It further releases, shears, and refines the gas-liquid mixture after it has been treated by the primary dissolved gas release head, so that the bubbles are further reduced to the micro-nano level, thereby forming a reinforced filtration flow field rich in micro-nano bubbles near the filter screen.

[0009] Furthermore, it also includes a brushing and scraping section, said brushing and scraping section comprising: A drive unit, which is mounted on the outside of the filter housing; A rotating shaft, one end of which is driven to the output end of the drive unit, and the other end extends into the interior of the filter housing and is disposed inside the filter screen or arranged parallel to the axis of the filter screen; A scraper / steel brush is mounted on the rotating shaft and is in close contact with the inner or outer surface of the filter screen. The drive unit drives the rotating shaft to rotate, thereby driving the scraper / steel brush to rotate, realizing mechanical brushing or scraping of the filter screen surface.

[0010] Furthermore, it also includes a solenoid valve installed in the gas-liquid delivery or gas release control path, the solenoid valve being used to control the proportion of water flow and gas entering the turbine; through the opening and closing control of the solenoid valve, the gas release intensity and injection state can be adjusted according to the filtration state.

[0011] Furthermore, a pressure gauge is installed on the inlet and outlet water passages of the filter area inside the filter screen of the filter housing. The pressure gauge is used to detect pressure or differential pressure changes during the operation of the filter.

[0012] Furthermore, it also includes a control unit, wherein the solenoid valve, the inlet three-phase valve, and the drive unit are all connected to the control unit, and the control unit performs automatic adjustment based on the pressure signal fed back by the pressure gauge.

[0013] Furthermore, a check valve is installed on the inlet pipe of the backwashing process to prevent backflow of water during the backwashing process, ensure the stability of the backwash water flow direction, and improve the safety of system operation.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention introduces micro-nano bubbles during the normal filtration stage, which can create continuous disturbance on the filter screen surface, reducing the deposition, aggregation, and compaction of impurity particles and adhesive dirt on the filter screen. This reduces the tendency to clog from the source and achieves a synergistic coupling of micro-nano bubble de-adhesion, mechanical disturbance to prevent deposition, and backwashing to enhance cleaning. This can effectively improve the filter's filtration performance, self-cleaning ability, and operational stability.

[0015] This invention incorporates an air inlet valve and turbine at the inlet, utilizing the inherent flow energy of the raw water to achieve air intake and primary aeration, eliminating the need for additional complex bubble generation equipment and resulting in a compact structure. Through two-stage dissolved air release heads (primary and secondary), the bubbles entering the filter are gradually reduced to micro-nano scale, thereby inhibiting dirt adhesion and compaction even during normal filtration.

[0016] This invention utilizes a dissolved gas release head injection combined with a steel brush assembly to enable the filter to have a slight self-cleaning ability during normal filtration operation. This changes the traditional mesh filter's working method of passive backwashing only after clogging. The mechanical cleaning component is composed of a rotating shaft, scraper / steel brush, and motor. During the backwashing stage, a three-phase valve is used to switch the direction to achieve reverse high-pressure flushing, and the motor drives the steel brush to rotate actively. This enables online slight decontamination during normal filtration and enhanced scrubbing during backwashing.

[0017] This invention forms a stable backwashing flow channel through a three-phase valve at the inlet, an inlet pipe for the backwashing process, and a check valve. It can quickly switch to the reverse flushing mode after the pressure difference increases, thereby improving the efficiency of dirt removal.

[0018] This invention integrates bubble decontamination, jet turbulence, mechanical scrubbing, and backwashing enhancement into one unit. It has a reasonable structure and is suitable for various scenarios such as agricultural irrigation, industrial circulating water, and reclaimed water filtration, and has good application value. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 A front view of a backwashing mesh filter based on micro-nano bubble enhanced filtration; Figure 2 A top view of a backwashing mesh filter based on micro-nano bubble enhanced filtration; Figure 3 A cross-sectional view of a backwashing mesh filter based on micro-nano bubble enhanced filtration; Figure 4 This refers to the normal filtration process of a backwashing mesh filter based on micro-nano bubble enhanced filtration. Figure 5 This describes the self-cleaning process of a backwash mesh filter based on micro-nano bubble enhanced filtration.

[0021] The components include: 1. Drain outlet; 2. Filter housing; 3. Check valve; 4. Backwashing process inlet pipe; 5. Inlet three-phase valve; 6. Inlet; 7. Solenoid valve; 8. Turbine; 9. Air inlet valve; 10. Pressure gauge; 11. Filtration process inlet pipe; 12. Outlet; 13. Secondary dissolved gas release head; 14. Primary dissolved gas release head; 15. Rotating shaft; 16. Scraper / steel brush; 17. Filter screen; 18. Motor. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] refer to Figures 1-5 A backwashing mesh filter based on micro-nano bubble enhanced filtration, comprising: The filter housing 2 has an outlet 12, a first inlet, a second inlet, and a drain outlet 1; The filter screen 17 is disposed inside the filter housing 2 and divides the internal space of the filter housing 2 into an inner filtration area and an outer water outlet area; wherein, the water outlet 12 and the second inlet are connected to the outer water outlet area of ​​the filter screen 17, and the first inlet and the drain outlet 1 are connected to the inner filtration area of ​​the filter screen 17. The filtration process inlet pipe 11 and the backwashing process inlet pipe 4 are connected. The first end of the filtration process inlet pipe 11 is connected to the first inlet, and the first end of the backwashing process inlet pipe 4 is connected to the second inlet. The second ends of the filtration process inlet pipe 11 and the backwashing process inlet pipe 4 are connected to the inlet three-phase valve 5. The third interface of the inlet three-phase valve 5 is the inlet 6. The inlet three-phase valve 5 is used to switch the inlet flow direction between normal filtration and backwashing conditions. The micro-nano bubble generator introduces gas into the water inlet area of ​​the filter housing 2 and forms a gas-liquid mixture rich in micro-nano bubbles. Under normal filtration conditions, raw water is introduced into the inner side of filter screen 17 through the three-phase valve 5 at the inlet and the inlet pipe 11 of the filtration process. Under backwashing conditions, raw water is introduced into the outer side of filter screen 17 through the backwashing inlet pipe 4 under the switching action of the three-phase valve 5 at the inlet, so as to form a reverse flushing water flow on filter screen 17.

[0025] Specifically, the filter housing 2 is the main supporting structure of the present invention. The filter screen 17 is disposed inside the filter housing 2, dividing the internal space of the filter into an inner filtration area and an outer water outlet area. The water outlet 12 is disposed on one side or the top of the filter housing 2 for discharging filtered clean water; the sewage outlet 1 is disposed at the bottom or end of the filter housing 2 for discharging the detached dirt and sewage during backwashing.

[0026] In this embodiment, the micro / nano bubble generator includes: The turbine 8 is installed in the inlet pipe 11 of the filtration process or in its adjacent flow channel. The turbine 8 is driven to rotate by the kinetic energy of the inlet water flow. Air inlet valve 9 is connected to an external air source or air and is used to introduce gas into the water inlet area. The gas entering the intake valve 9 forms micron-sized primary bubbles under the high-speed shearing and crushing action of the turbine 8, and mixes with the water entering the filter housing 2 to form a primary gas-liquid mixture.

[0027] In this embodiment, the micro / nano bubble generator further includes: The first-stage dissolved gas release head 14 is located in the filtration area inside the filter screen 17. It is set inside the filter housing 2 near the water inlet area or the front end of the filter screen 17 to refine and uniformly disperse the gas-liquid mixture after initial crushing by the turbine 8, so that the bubbles are further reduced and a more uniform gas-containing water flow is formed inside the filter screen 17. The secondary dissolved gas release head 13 is located in the filtration zone inside the filter screen 17. It is set near the filter screen 17 or distributed along the axial direction of the filter screen 17 to further release, shear and refine the gas-liquid mixture after it has been treated by the primary dissolved gas release head 14, so that the bubbles are further reduced to the micro-nano level, thereby forming a reinforced filtration flow field rich in micro-nano bubbles near the filter screen 17.

[0028] The backwashing mesh filter based on micro-nano bubble enhanced filtration provided in this embodiment also includes a brush and scraper section, which includes: The drive unit is installed on the outside of the filter housing 2; The rotating shaft 15 has one end connected to the output end of the drive unit and the other end extends into the interior of the filter housing 2 and is disposed inside the filter screen 17 or arranged parallel to the axis of the filter screen 17. Scraper / steel brush 16 is mounted on the rotating shaft 15 and is in close contact with the inner or outer surface of the filter screen 17. The drive unit drives the rotating shaft 15 to rotate, thereby driving the scraper / steel brush 16 to rotate, realizing mechanical brushing or scraping of the surface of the filter screen 17.

[0029] Specifically, the drive unit can be a hydraulic motor, a pneumatic motor, or an electric motor 18, with an electric motor 18 being preferred.

[0030] The motor 18 is connected to the rotating shaft 15 for driving the rotating shaft 15 to rotate, thereby driving the scraper / steel brush 16 to rotate, so as to achieve mechanical brushing or scraping of the surface of the filter screen 17.

[0031] During normal filtration, the motor 18 can operate intermittently or at low speed. The scraper / steel brush 16, aided by the jet flow from the secondary dissolved air release head 13 and driven by the rotating shaft 15, provides gentle, continuous agitation to the surface of the filter screen 17. Simultaneously, micro-nano bubbles flow through the filter screen 17 with the water, trapping impurities on its surface. The bubbles continuously adhere, coalesce, and burst on the filter screen surface, in the gaps between dirt particles, and in localized high-shear areas. The localized disturbance generated by the bursting of bubbles loosens, breaks down, and destabilizes the already attached dirt, thereby reducing the deposition, compaction, and adhesion of dirt on the surface of the filter screen 17. The filtered clean water is discharged from the outlet 12.

[0032] The backwashing mesh filter based on micro-nano bubble enhanced filtration provided in this embodiment also includes an electromagnetic valve 7 disposed in the gas-liquid delivery or gas release control passage. The electromagnetic valve 7 is used to control the ratio of water flow and gas entering the turbine 8. By controlling the opening and closing of the electromagnetic valve 7, the gas release intensity and injection state can be adjusted according to the filtration state.

[0033] In this embodiment, a check valve 3 is installed on the backwash inlet pipe 4 to prevent backflow of water during the backwash process, ensure the stability of the backwash water flow direction, and improve the safety of system operation.

[0034] In this embodiment, a pressure gauge 10 is installed on the inlet and outlet water passages of the filter area inside the filter screen 17 of the filter housing 2. The pressure gauge 10 is used to detect pressure or differential pressure changes during filter operation. When the pressure gauge 10 shows that the system differential pressure increases to a set threshold, it indicates that a lot of dirt has accumulated on the surface of the filter screen 17, and the system enters the backwashing state.

[0035] During the backwashing process, the inlet three-phase valve 5 switches the flow channel, closes the normal filtration process inlet pipe 11, and opens the backwash process inlet pipe 4, so that the backwash water flow directly enters the outer area of ​​the filter screen 17 and passes through the filter screen 17 in reverse from the outside to the inside under pressure.

[0036] The reverse high-pressure water flow impacts and peels off the dirt layer adhering to the surface of the filter screen 17; at the same time, the motor 18 starts and drives the rotating shaft 15 to rotate, driving the scraper / steel brush 16 to perform enhanced mechanical scraping on the surface of the filter screen 17. The dirt that is removed by reverse flushing and mechanical brushing is finally discharged with the sewage through the drain outlet 1.

[0037] Through the above structural design, this invention integrates "inlet air intake - turbine primary air breaking - primary dissolved air release - secondary micro-nano air release - filtration process de-adhesion - backwashing reverse flushing - scraper / steel brush enhanced peeling" into one unit. It can not only inhibit dirt adhesion and compaction during the normal filtration stage, but also significantly enhance the dirt removal effect during the backwashing stage, thereby improving the filtration efficiency, self-cleaning ability and operational stability of the mesh filter.

[0038] Example 2

[0039] This embodiment describes the normal filtration process based on the backwashing mesh filter with micro-nano bubble enhanced filtration provided in Embodiment 1.

[0040] In this embodiment, the backwashing mesh filter based on micro-nano bubble enhanced filtration operates under normal filtration conditions. The inlet three-phase valve 5 switches to the filtration channel, and raw water flows into the filter housing 2 through the filtration process inlet pipe 11. The water flow first passes through the turbine 8 located near the inlet 6, which rotates under hydraulic pressure. Simultaneously, air enters through the air inlet valve 9 and is broken into micron-sized primary bubbles under the shearing action of the turbine 8, mixing with the water flow to form a primary gas-liquid mixture.

[0041] With solenoid valve 7 open, the primary gas-liquid mixture flows sequentially into the first-stage dissolved gas release head 14 and the second-stage dissolved gas release head 13. The first-stage dissolved gas release head 14 disperses and refines the gas-liquid mixture for the first time, further reducing the bubble size and making it more uniformly distributed. The second-stage dissolved gas release head 13 further refines the bubbles to the micro-nano level and sprays them into the area near the filter screen 17, forming a reinforced filtration flow field rich in micro-nano bubbles.

[0042] Water containing micro-nano bubbles flows from the inside to the outside of filter screen 17, trapping suspended particles, silt, and organic impurities. Because the micro-nano bubbles are continuously present on the surface of filter screen 17 and between dirt particles, they weaken the adhesion between particles and between particles and the filter screen. These bubbles also rupture during flow rate fluctuations and local pressure changes, creating micro-scale disturbances that prevent dirt from easily caking and compacting on the surface of filter screen 17. Simultaneously, the jet stream from the secondary dissolved air release head 13 creates a disturbance on the scraper / steel brush 16, which, combined with the low-speed rotation of the rotating shaft 15, continuously and gently scrubs the surface of filter screen 17, further reducing the rate of dirt deposition. The filtered water is finally discharged from the outlet 12.

[0043] Example 3

[0044] This embodiment describes the backwashing process based on the backwashing mesh filter with micro-nano bubble enhanced filtration provided in Embodiments 1 and 2.

[0045] When the backwashing mesh filter based on micro-nano bubble enhanced filtration continues to operate, as the surface of the filter screen 17 becomes increasingly dirty, the system resistance increases, and the pressure difference between the filter inlet and outlet reaches a preset value. At this time, the system switches to backwashing mode, the three-phase valve 5 at the inlet closes the inlet water pipe 11 for the filtration process, and opens the inlet water pipe 4 for the backwash process, allowing the backwash water to flow through the check valve 3 and into the filter housing 2, and then directly into the outer area of ​​the filter screen 17.

[0046] During backwashing, water flows in the opposite direction from the outside to the inside of filter screen 17, passing through the screen and performing a reverse high-pressure flushing of the dirt adhering to its surface. Simultaneously, motor 18 starts, driving shaft 15 to rotate, which in turn moves scraper / steel brush 16 along the surface of filter screen 17, further scraping and washing away the dirt loosened by the reverse water flow. Because the micro-nano bubbles weaken the adhesion of the dirt during normal filtration, the dirt layer is more easily peeled off or broken up during backwashing. The detached dirt and backwash wastewater are discharged from the filter housing 2 through drain port 1. After backwashing, the inlet three-phase valve 5 returns to its original position, and the device re-enters normal filtration mode.

[0047] Example 4

[0048] This embodiment describes the continuous operation mode based on the backwashing mesh filter with micro-nano bubble enhanced filtration provided in Embodiments 1, 2 and 3.

[0049] In a preferred embodiment, the solenoid valve 7, the inlet three-phase valve 5, and the motor 18 are all connected to the control unit, which automatically adjusts the system based on the pressure signal fed back by the pressure gauge 10. During normal filtration, the control unit controls the solenoid valve 7 to open periodically, causing the primary dissolved air release head 14 and the secondary dissolved air release head 13 to release gas intermittently or continuously, thereby maintaining the concentration of micro-nano bubbles near the filter screen 17. Simultaneously, the control unit controls the motor 18 to drive the rotating shaft 15 to rotate at low speed or intermittently, achieving slight online decontamination of the filter screen 17 surface. When the pressure difference reaches a set threshold, the control unit controls the inlet three-phase valve 5 to switch and starts the motor 18 to run at high speed, entering the backwashing mode; after backwashing, the system returns to normal filtration mode.

[0050] Example 5

[0051] This embodiment illustrates the application effect based on the backwashing mesh filter with micro-nano bubble enhanced filtration provided by the present invention.

[0052] This invention is applicable to various scenarios, including agricultural irrigation head filtration systems, brackish water or reclaimed water pretreatment systems, industrial circulating water filtration systems, and landscape water purification. Compared to traditional mesh filters, this invention constructs a micro-nano bubble-enhanced filtration environment during the normal filtration stage through a turbine 8, an air inlet valve 9, a primary dissolved air release head 14, and a secondary dissolved air release head 13, weakening the adhesion and compaction tendency of dirt before it forms. During the backwashing stage, the inlet three-phase valve 5 switches the reverse flow channel, and combined with a scraper / steel brush 16 driven by a motor 18, it achieves enhanced peeling, thereby improving the regeneration effect of the filter screen 17, reducing the clogging rate, and extending the stable operation time of the equipment.

[0053] The technical solutions of the present invention have been fully described above. It should be noted that the specific embodiments of the present invention are not limited to the above description. All technical solutions formed by those skilled in the art based on the spirit and essence of the present invention by adopting equivalent transformations or equivalent transformations in terms of structure, method or function fall within the protection scope of the present invention.

Claims

1. A backwashing mesh filter based on micro / nano bubble enhanced filtration, characterized in that, include: A filter housing having a water outlet, a first inlet, a second inlet, and a drain outlet; A filter screen is disposed inside the filter housing and divides the internal space of the filter housing into an inner filtration area and an outer water outlet area; wherein the water outlet and the second inlet are connected to the outer water outlet area, and the first inlet and the drain outlet are connected to the inner filtration area. The filter process inlet pipe and the backwash process inlet pipe are provided. The first end of the filter process inlet pipe is connected to the first inlet, and the first end of the backwash process inlet pipe is connected to the second inlet. The second ends of the filter process inlet pipe and the backwash process inlet pipe are connected to the inlet three-phase valve. The third interface of the inlet three-phase valve is the inlet. A micro-nano bubble generator, wherein the micro-nano bubble generator introduces gas into the water inlet area of ​​the filter housing and forms a gas-liquid mixture rich in micro-nano bubbles; In normal filtration conditions, raw water is introduced into the inner side of the filter screen through the inlet three-phase valve and the filtration process inlet pipe. In backwashing conditions, raw water is introduced into the outer side of the filter screen through the backwash process inlet pipe under the switching action of the inlet three-phase valve, so as to form a reverse flushing water flow on the filter screen.

2. The backwashing mesh filter based on micro-nano bubble enhanced filtration according to claim 1, characterized in that, The micro / nano bubble generator includes: A turbine, which is installed in the inlet pipe of the filtration process or in an adjacent flow channel, is driven to rotate by the kinetic energy of the inlet flow; An air intake valve, which is connected to an external air source or air, is used to introduce gas into the water intake area; The gas entering the intake valve forms micron-sized primary bubbles under the high-speed shearing and crushing action of the turbine, and mixes with the water flowing into the filter housing.

3. The backwashing mesh filter based on micro / nano bubble enhanced filtration according to claim 2, characterized in that, The micro / nano bubble generator also includes: The first-stage dissolved gas release head is located in the filtration zone inside the filter screen. It is set inside the filter housing near the water inlet area or at the front end of the inner side of the filter screen to refine and uniformly disperse the gas-liquid mixture after initial crushing by the turbine, so that the bubbles are further reduced and a more uniform gas-containing water flow is formed inside the filter screen. The secondary dissolved gas release head is located in the filtration zone inside the filter screen, and is set near the filter screen or distributed along the filter screen axis. It further releases, shears, and refines the gas-liquid mixture after it has been treated by the primary dissolved gas release head, so that the bubbles are further reduced to the micro-nano level, thereby forming a reinforced filtration flow field rich in micro-nano bubbles near the filter screen.

4. The backwashing mesh filter based on micro-nano bubble enhanced filtration according to claim 3, characterized in that, It also includes a scrubbing and scraping brush section, which includes: A drive unit, which is mounted on the outside of the filter housing; A rotating shaft, one end of which is driven to the output end of the drive unit, and the other end extends into the interior of the filter housing and is disposed inside the filter screen or arranged parallel to the axis of the filter screen; A scraper / steel brush is mounted on the rotating shaft and is in close contact with the inner or outer surface of the filter screen. The drive unit drives the rotating shaft to rotate, thereby driving the scraper / steel brush to rotate, realizing mechanical brushing or scraping of the filter screen surface.

5. The backwashing mesh filter based on micro / nano bubble enhanced filtration according to claim 4, characterized in that, It also includes a solenoid valve installed in the gas-liquid delivery or gas release control path, the solenoid valve being used to control the proportion of water flow and gas entering the turbine; by controlling the opening and closing of the solenoid valve, the gas release intensity and injection state can be adjusted according to the filtration state.

6. The backwashing mesh filter based on micro-nano bubble enhanced filtration according to claim 5, characterized in that, Pressure gauges are installed on the inlet and outlet water passages of the filter area inside the filter screen of the filter housing. The pressure gauges are used to detect pressure or differential pressure changes during the operation of the filter.

7. The backwashing mesh filter based on micro / nano bubble enhanced filtration according to claim 6, characterized in that, It also includes a control unit, and the solenoid valve, the inlet three-phase valve and the drive unit are all connected to the control unit. The control unit automatically adjusts the pressure based on the pressure signal fed back by the pressure gauge.

8. The backwashing mesh filter based on micro / nano bubble enhanced filtration according to claim 2, characterized in that, A check valve is installed on the inlet pipe of the backwash process to prevent backflow of water during backwashing, ensure the stability of the backwash water flow direction, and improve the safety of system operation.

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