Automatic backwash filtration system and control method

Abstract

The application provides an automatic backwashing filtration system and a control method, comprising: a tank body, the tank body having a filter layer inside; a differential pressure detection unit for detecting the operation pressure difference between the water inlet end and the bottom water collecting area of the tank body; a first water quality detection unit for detecting the turbidity of produced water; a second water quality detection unit for detecting the turbidity of backwashing drainage water; a backwashing execution unit for executing the backwashing program of the drainage step, the cleaning step and the positive washing step; and a control unit signal connected with the differential pressure detection unit, the first water quality detection unit, the second water quality detection unit and the backwashing execution unit, wherein, during the production of water, when the turbidity of produced water is detected to be greater than or equal to a first turbidity threshold or the operation pressure difference is greater than or equal to a pressure difference threshold, the control unit controls the backwashing execution unit to start the backwashing program; during the positive washing, when the turbidity of backwashing drainage water is detected to be less than or equal to a second turbidity threshold and the operation pressure difference is less than or equal to the pressure difference threshold, the control unit determines that the backwashing is completed and the production of water is restored, realizes the accurate control of the whole process of the backwashing process, improves the backwashing effect and reduces the operation energy consumption.

Description

Technical Field

[0001] This invention relates to the field of filtration technology, specifically to an automatic backwashing filtration system and control method. Background Technology

[0002] Multi-media filters, as key pretreatment equipment in water treatment systems, are widely used in industrial and municipal water supply. They utilize the graded retention effect of multiple layers of filter media, such as quartz sand and anthracite, to effectively remove suspended solids, colloids, and particulate matter from raw water, reducing the load on subsequent treatment units. However, with continuous operation of the filtration process, the filter media gradually traps impurities and becomes clogged, leading to increased filtration resistance, decreased water production, and water quality deterioration. Therefore, periodic backwashing is necessary to restore the filtration performance of the filter media.

[0003] In existing technologies, backwashing triggering methods for multi-media filters mainly rely on manual inspection, a single preset time period, or monitoring by local differential pressure sensors. These methods have significant limitations: manual inspection is highly subjective and has a delayed response, making timely backwashing difficult; fixed time periods cannot adapt to fluctuations in raw water quality, easily leading to untimely or excessive backwashing; and differential pressure sensors are typically only located at the inlet and outlet of the filter, failing to comprehensively reflect the internal blockage distribution of the filter media, resulting in inaccurate judgment of backwashing timing and consequently affecting the continuous and stable operation of the filtration system.

[0004] Furthermore, there is a lack of precise control over the liquid level in the filter media layer during backwashing. If the backwash water level is too high, the filter media will be lost with the backwash water, resulting in a reduction in the thickness of the filter media layer and damage to the gradation. If the backwash water level is too low, the filter media will not be able to expand and fluidize sufficiently, and impurities will be difficult to effectively peel off from the surface of the filter media. Long-term operation will cause the filter media to clump and agglomerate, which will seriously reduce the backwashing efficiency and filtration cycle.

[0005] Meanwhile, existing backwashing systems generally lack real-time water quality monitoring components in the backwash drainage pipeline, making it impossible to dynamically determine the degree of filter media cleaning based on changes in drainage turbidity. Backwashing operations are usually performed according to fixed air washing and water washing times and steps, continuing backwashing even when the filter media is already clean, resulting in unnecessary waste of water and energy resources, and making it difficult to guarantee that the filter media will return to an ideal clean state after each backwash.

[0006] Therefore, how to solve the problems of single monitoring, poor cleaning effect, high energy consumption and water consumption in the existing multi-media filter backwashing structure? Summary of the Invention

[0007] The problem solved by this invention is to provide an automatic backwashing filtration system and control method, which realizes precise control of the entire backwashing process, improves the backwashing effect, and reduces operating energy consumption.

[0008] To address the aforementioned problems, this invention provides an automatic backwashing filtration system, comprising: a tank having a filter media layer inside; a differential pressure detection unit for detecting the operating pressure difference between the inlet end and the bottom water collection area of ​​the tank; a first water quality detection unit located on the product water side for detecting the turbidity of the product water; a second water quality detection unit located on the outlet side for detecting the turbidity of the backwash outlet water; a backwash execution unit for executing a backwashing procedure consisting of an outlet water step, a cleaning step, and a forward washing step; and a control unit connected to the differential pressure detection unit, the first water quality detection unit, the second water quality detection unit, and the backwash execution unit via signals. During the product water process, when the product water turbidity is detected to be ≥ a first turbidity threshold or the operating differential pressure is detected to be ≥ a differential pressure threshold, the control unit controls the backwash execution unit to initiate the backwashing procedure. During the forward washing process, when the backwash outlet turbidity is detected to be ≤ a second turbidity threshold and the operating differential pressure is detected to be ≤ a differential pressure threshold, the control unit determines that the backwashing is complete and resumes product water production.

[0009] Optionally, if the backwash drainage turbidity is detected to be ≥ the second turbidity threshold or the operating pressure difference is detected to be ≥ the pressure difference threshold, the control unit controls the backwash execution unit to add a cleaning step and re-execute the forward washing step until the backwash drainage turbidity is ≤ the second turbidity threshold and the operating pressure difference is ≤ the pressure difference threshold.

[0010] Optionally, the cleaning steps include a water washing step, an air washing step, and a water washing combined with an air washing step.

[0011] Optionally, the backwash execution unit includes a drainage module, which includes a drainage pipe connected to the tank and a positive discharge valve disposed on the drainage pipe. The second water quality detection unit is disposed on the drainage pipe. The control unit is configured to: control the opening of the positive discharge valve before starting the backwash procedure to lower the water level in the tank to a preset position above the filter media layer; and receive the turbidity of the backwash drainage detected by the second water quality detection unit during the positive wash step.

[0012] Optionally, the backwashing execution unit further includes an air washing module, which includes an air washing pipeline connected to the bottom of the tank, an air washing fan connected to the air washing pipeline, an air inlet valve on the air washing pipeline, and an exhaust valve connected to the top of the tank. The control unit is configured to: in the air washing step and the water washing combined air washing step, turn on the air washing fan, the air inlet valve and the exhaust valve to introduce gas into the filter layer.

[0013] Optionally, the backwash execution unit further includes a backwash water inlet module, which includes a backwash water inlet pipeline connected to the bottom of the tank, a backwash pump connected to the backwash water inlet pipeline, and a backwash valve provided on the backwash water inlet pipeline; the control unit is configured to: in the water washing step and the water washing combined with air washing step, turn on the backwash pump and the backwash valve to introduce backwash water into the tank.

[0014] Optionally, the backwash execution unit further includes a backwash drainage module, which includes a backwash drainage pipeline connected to the tank and a backwash valve disposed thereon; the control unit is configured to: in the water washing step and the water washing combined with air washing step, open the backwash valve to discharge backwash wastewater and backwash waste gas.

[0015] Optionally, it also includes a water inlet module that is signal-connected to the control unit. The water inlet module includes a water inlet pipe that is connected to the water inlet end of the tank, a water inlet pump that is connected to the water inlet pipe, and a water inlet valve that is provided on the water inlet pipe.

[0016] Optionally, it also includes a water production module connected to the control unit. The water production module includes a water production pipeline connected to the bottom water collection area and a water production valve located on the water production pipeline. The first water quality detection unit is located on the water production pipeline. The control unit is configured to: during the water production process, turn on the water inlet pump, the water inlet valve, and the water production valve to introduce raw water into the tank and produce filtered water through the filter media layer; when the turbidity of the produced water is ≥ a first turbidity threshold or the operating pressure difference is ≥ a pressure difference threshold, close the water inlet valve and the water production valve.

[0017] Optionally, the backwash execution unit further includes a forward wash module, which includes the water inlet module and the forward drain valve in the drainage module; the control unit is configured to: in the forward wash step, turn on the water inlet pump, the water inlet valve and the forward drain valve to introduce raw water into the tank for forward wash.

[0018] The present invention also provides a control method for an automatic backwashing filtration system, providing a tank and a filter media layer located within the tank, including a water production step: introducing raw water into the tank, filtering it through the filter media layer, and then entering the bottom water collection area for water production; a monitoring step: during the water production process, detecting the turbidity of the produced water on the water production side, and detecting the operating pressure difference between the water inlet of the tank and the bottom water collection area; a triggering step: when the turbidity of the produced water is detected to be ≥ a first turbidity threshold or the operating pressure difference is detected to be ≥ a pressure difference threshold, initiating a backwashing program; the backwashing program includes a drainage step, a cleaning step, and a forward washing step performed sequentially; a verification step: in the forward washing step, detecting the turbidity of the backwash drainage on the drainage side, and detecting the operating pressure difference; a determination step: when the turbidity of the backwash drainage is detected to be ≤ a second turbidity threshold and the operating pressure difference is detected to be ≤ the pressure difference threshold, determining that the backwashing program has ended and resuming the water production step.

[0019] Optionally, a compensation step is also included: if the backwash drainage turbidity is detected to be ≥ the second turbidity threshold or the operating pressure difference is detected to be ≥ the pressure difference threshold, then an additional cleaning step is added, and the forward washing step and the verification step are re-executed until the backwash drainage turbidity is detected to be ≤ the second turbidity threshold and the operating pressure difference is detected to be ≤ the pressure difference threshold.

[0020] Compared with the prior art, the technical solution of the present invention has the following advantages: In the technical solution of the automatic backwashing filtration system of this invention, during the water production process, the turbidity of the unit's produced water and the operating pressure difference are controlled as dual-parameter triggering conditions. When the turbidity of the produced water is greater than or equal to the first turbidity threshold or the operating pressure difference is greater than or equal to the pressure difference threshold, if the turbidity of the produced water increases, it indicates that the filter media layer's ability to intercept and filter impurities such as suspended solids and colloids has decreased, and impurities penetrate the filter media layer and enter the produced water side, leading to the deterioration of the produced water quality. Conversely, if the operating pressure difference increases, it indicates that the filter media layer has intercepted too many impurities, causing blockage. The filter media pores are filled with impurities, significantly increasing the water flow resistance, and the pressure loss between the inlet and the bottom water collection area exceeds the normal range. Therefore, if any of the above situations occur... The current situation indicates that the filter media layer can no longer maintain normal filtration performance, and a backwashing procedure needs to be initiated promptly to restore its filtration capacity. Therefore, when either of these two parameters is detected to exceed the set threshold, the control unit receives a signal and controls the backwashing execution unit to start the backwashing procedure, which includes drainage, cleaning, and forward washing steps. This effectively overcomes the problems of untimely or excessive backwashing, achieving effective and timely detection. Furthermore, during the forward washing process, the control unit uses the turbidity of the backwash drainage and the operating pressure difference as dual judgment conditions. When the turbidity of the backwash drainage is less than or equal to the second turbidity threshold and the operating pressure difference is less than or equal to the pressure difference threshold, the backwashing is deemed complete and production water is restored. This dynamic endpoint determination mechanism can terminate backwashing in real time based on the actual cleaning effect, avoiding filter media layer blockage caused by switching to production water before the filter media is properly cleaned, and preventing water and energy waste caused by excessive backwashing. In addition, the differential pressure detection unit detects the operating pressure difference between the water inlet and the bottom water collection area of ​​the tank. The obtained data can more comprehensively reflect the overall blockage and resistance distribution of the filter media layer, providing a more reliable basis for backwash triggering and endpoint judgment. This enables accurate determination of backwash timing, dynamic evaluation of backwash endpoint, and full-process automated control, effectively ensuring the filtration performance of the filter media layer and having a wide range of applications. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an automatic backwashing filtration system in one embodiment of the present invention. Detailed Implementation

[0022] Existing backwashing systems suffer from problems such as limited backwashing trigger conditions, unreasonable sensor layout, lack of precise control over filter media liquid level, and lack of real-time water quality monitoring of backwash drainage. These issues lead to untimely or excessive backwashing, filter media caking, and waste of water and energy.

[0023] Based on this, the present invention provides an automatic backwashing filtration system. When either the turbidity of the permeate water or the operating pressure difference, which indicates that the filter media layer can no longer maintain normal filtration performance, exceeds a set threshold, the control unit receives a signal and controls the backwashing execution unit to start a backwashing program including a drainage step, a cleaning step, and a forward washing step. This effectively overcomes the problems of untimely or excessive backwashing and achieves effective and timely detection. Furthermore, during the forward washing process, the control unit uses the turbidity of the backwash drainage and the operating pressure difference as dual judgment conditions. When the turbidity of the backwash drainage is less than or equal to a second turbidity threshold and the operating pressure difference is less than or equal to a pressure difference threshold, the backwashing is determined to be complete and permeate water production is restored. This dynamic endpoint determination mechanism can terminate backwashing in real time based on the actual cleaning effect, avoiding filter media layer blockage caused by transferring to permeate water before the filter media is cleaned, and preventing water and energy waste caused by excessive backwashing. In addition, the differential pressure detection unit detects the operating pressure difference between the water inlet and the bottom water collection area of ​​the tank. The obtained data can more comprehensively reflect the overall blockage and resistance distribution of the filter media layer, providing a more reliable basis for backwash triggering and endpoint judgment. This enables accurate determination of backwash timing, dynamic evaluation of backwash endpoint, and full-process automated control, effectively ensuring the filtration performance of the filter media layer and having a wide range of applications.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] Please refer to the reference. Figure 1 An automatic backwashing filtration system includes a tank 100, a differential pressure detection unit 101, a first water quality detection unit 102, a second water quality detection unit 103, a backwashing execution unit (not shown in the figure), and a control unit (not shown in the figure).

[0026] In this embodiment, the tank 100 has a filter layer 100a inside. The differential pressure detection unit 101 is used to detect the operating pressure difference between the water inlet and the bottom water collection area of ​​the tank 100. The first water quality detection unit 102 is located on the product water side and is used to detect the turbidity of the product water. The second water quality detection unit 103 is located on the drainage side and is used to detect the turbidity of the backwash drainage. The backwash execution unit is used to execute the backwash procedure of drainage step, cleaning step and forward washing step. The control unit (not shown in the figure) is connected to the differential pressure detection unit 100a. 01. The first water quality detection unit 102, the second water quality detection unit 103, and the backwash execution unit are signal connected. During the water production process, when the turbidity of the produced water is greater than or equal to the first turbidity threshold or the operating pressure difference is greater than or equal to the pressure difference threshold, the control unit (not shown in the figure) controls the backwash execution unit to start the backwash program. During the forward washing process, when the turbidity of the backwash drainage is less than or equal to the second turbidity threshold and the operating pressure difference is less than or equal to the pressure difference threshold, the control unit (not shown in the figure) determines that the backwash is completed and restores water production.

[0027] In this embodiment, since the turbidity of the produced water characterizes the ability of the filter media layer 100a to retain and filter impurities such as suspended solids and colloids, and the operating pressure difference reflects the physical state of the filter media layer 100a, which is blocked due to excessive impurities, the filter pores are filled with impurities, and the water flow resistance is significantly increased, the turbidity of the produced water and the operating pressure difference are used as dual-parameter triggering conditions. As long as either of the two values ​​exceeds or reaches the corresponding set threshold range, the control reaction will control the backwash execution unit to execute the backwash program. This comprehensive monitoring of the operating status of the filter media layer 100a from two dimensions of turbidity and pressure can improve the accuracy and timeliness of backwash triggering judgment, effectively avoid misjudgment or response lag caused by single parameter monitoring, and ensure that the backwash program is started in time when the filtration performance of the filter media layer 100a declines. This overcomes the problems of untimely or excessive backwashing, prevents the deterioration of the produced water quality and further blockage of the filter media layer 100a, avoids the waste of water resources and energy, and ensures the continuous and stable operation of the filtration system.

[0028] In this embodiment, the tank 100 also has a support layer (not shown in the figure). In the multi-media filter, the support layer (not shown in the figure) is located between the filter media layer 100a and the bottom water collection area, supporting the filter media layer 100a from bottom to top. The support layer (not shown in the figure) is usually composed of relatively large and graded quartz sand, gravel, or pebbles, etc., with its particle size gradually decreasing from bottom to top, but all larger than the particle size of the filter media in the upper filter media layer 100a.

[0029] In this embodiment, the tank 100 includes a top water inlet area I and a bottom water collection area II. The differential pressure detection unit 101 includes an inlet differential pressure sensor (not shown in the figure) and a product water differential pressure sensor (not shown in the figure). The inlet differential pressure sensor is installed in the top water inlet area I of the tank 100, and the product water differential pressure sensor is installed in the bottom water collection area II. The inlet differential pressure sensor and the product water differential pressure sensor cooperate to detect the operating pressure difference between the top water inlet area I and the bottom water collection area II, and transmit the detected operating pressure difference signal to the control unit (not shown in the figure). Since the inlet differential pressure sensor and the product water differential pressure sensor are located above and below the filter media layer 100a, respectively, the obtained operating pressure difference can comprehensively reflect the overall blockage and resistance distribution of the filter media layer 100a, providing a more reliable physical basis for backwash triggering and endpoint determination.

[0030] In this embodiment, the top of the tank 100 is connected to a water inlet module, which is signal-connected to the control unit (not shown in the figure). The water inlet module includes a water inlet pipe 104 connected to the water inlet end of the tank 100, a water inlet pump 1041 connected to the water inlet pipe 104, and a water inlet valve 1042 provided on the water inlet pipe 104.

[0031] In this embodiment, the control unit (not shown in the figure) controls the opening and closing of the inlet pump 1041 and the inlet valve 1042. Regardless of whether the control unit (not shown in the figure) detects that the turbidity of the produced water is greater than or equal to a preset threshold or that the operating pressure difference is greater than or equal to a threshold, the control unit (not shown in the figure) will close the inlet pump 1041 and the inlet valve 1042, thus blocking the inlet pipeline 104 and allowing the subsequent backwashing procedure to proceed. After the backwashing procedure is completed, when the turbidity of the discharged water and the operating pressure difference both meet the requirements, the control unit (not shown in the figure) will open the inlet pump 1041 and the inlet valve 1042 to continue producing water.

[0032] In this embodiment, the top of the tank 100 has a water distribution plate (not shown in the figure). The water distribution plate (not shown in the figure) is located above the filter media layer 100a and is connected to the water inlet pipe 104. After the water is evenly distributed by the water distribution plate (not shown in the figure), it flows through the filter media layer 100a and the support layer (not shown in the figure) to complete the filtration. The filtered clean water is discharged through the water production pipe.

[0033] In this embodiment, the bottom water collection area II is also connected to a water production module that is signal-connected to the control unit (not shown in the figure). The water production module includes a water production pipeline 105 connected to the bottom water collection area II, a water production valve 1051 disposed on the water production pipeline 105, and a first water quality detection unit 102 disposed on the water production pipeline 105. The control unit (not shown in the figure) is configured to: during the water production process, turn on the inlet pump 1041, the inlet valve 1042, and the water production valve 1051 to introduce raw water into the tank 100 and produce filtered water through the filter media layer 100a; when the turbidity of the produced water is ≥ the first turbidity threshold or the operating pressure difference is ≥ the pressure difference threshold, the control unit (not shown in the figure) closes the inlet valve 1042, the water production valve 1051, and the inlet pump 1041.

[0034] In this embodiment, the inlet valve 1042 and the product valve 1051 can be solenoid valves, pneumatic diaphragm valves or electric butterfly valves, and these valves can form an automated control with the control unit (not shown in the figure).

[0035] In this embodiment, the first water quality detection unit 102 is a turbidity sensor. The first water quality detection unit 102 detects the turbidity value of the filtered water on the water production pipeline 105 and transmits it to the control unit (not shown in the figure). The control unit (not shown in the figure) compares the currently detected turbidity value with the first turbidity threshold to detect whether the backwashing procedure has been triggered.

[0036] It should be noted that the turbidity detected by the first water quality detection unit 102 can be fed back to the control unit (not shown in the figure) in real time, and the control unit (not shown in the figure) can perform real-time detection and comparison; alternatively, the control unit (not shown in the figure) can be set to a time period, and the first water quality detection unit 102 can detect the corresponding turbidity and feed it back to the control unit (not shown in the figure) at the specified time, and the control unit can perform comparison. The choice can be made according to the actual needs.

[0037] In this embodiment, the backwash execution unit includes a drainage module, which includes a drainage pipe 106 connected to the tank 100 and a positive discharge valve 1061 disposed on the drainage pipe 106. The second water quality detection unit 103 is disposed on the drainage pipe 106. The control unit (not shown in the figure) is configured to: control the opening of the positive discharge valve 1061 before starting the backwash procedure to lower the water level in the tank 100 to a preset position above the filter media layer 100a; and receive the turbidity of the backwash drainage detected by the second water quality detection unit 103 during the positive wash step.

[0038] In this embodiment, the backwash execution unit further includes a forward wash module, which includes the water inlet module and the forward drain valve 1061 in the drainage module. The control unit (not shown in the figure) is configured to: in the forward wash step, turn on the water inlet pump 1041, the water inlet valve 1042 and the forward drain valve 1061 to introduce raw water into the tank 100 for forward wash. This means that after the cleaning step is completed, the entire tank 100 needs to be discharged to remove impurities, so that the filter media layer 100a is recompacted and the gradation is restored. At the same time, the turbid water and stripped impurities remaining during the backwash process are discharged through the drainage pipe 106 until the second water quality detection unit 103 detects that the turbidity of the backwash drainage is less than or equal to the second turbidity threshold and the operating pressure difference is less than or equal to the pressure difference threshold, thereby ensuring that the inside of the tank 100 is clean and the filtration performance of the filter media layer 100a is restored, providing conditions for restoring water production.

[0039] In this embodiment, the second water quality detection unit 103 is a turbidity meter.

[0040] In this embodiment, the positive discharge valve 1061 and the second water quality detection unit 103 are signal-connected to the control unit (not shown in the figure). The control unit (not shown in the figure) first controls the opening of the positive discharge valve 1061, so that part of the water in the tank 100 is discharged until the water level drops to a preset position above the filter media layer 100a. This ensures the subsequent backwashing effect and prevents filter media loss. Specifically, if the water level is too high, the gas cannot fully enter the bottom of the filter media layer 100a in the subsequent air washing step, resulting in the filter media not being able to expand and fluidize effectively, and impurities not being able to be peeled off from the surface of the filter media. At the same time, an excessively high water level will make the water cushion layer on top of the filter media layer 100a too thick during air washing or water washing, weakening the agitation effect of the airflow or water flow on the filter media, resulting in incomplete cleaning. If the water level is too low, the filter media may be exposed to the air, and the filter media is easily lost or its gradation is damaged during air washing. In addition, the filter media cannot be fully suspended in the water, which also affects the backwashing effect.

[0041] In this embodiment, a liquid level sensor (not shown in the figure) is installed on the inner wall of the tank 100. The liquid level sensor is a differential pressure type, with the high-pressure side pressure tap located above the filter media layer 100a and the low-pressure side pressure tap located in the bottom water collection area II. It detects the water level in the tank 100 in real time with a monitoring accuracy of ±5mm. Its function is to: control the opening of the positive discharge valve 1061 before starting the backwashing procedure, lowering the water level in the tank 100 to a preset position above the filter media layer 100a. By detecting the pressure difference change between the area above the filter media layer 100a and the bottom water collection area II, the area above the filter media layer 100a is directly used as the reference benchmark for liquid level control, accurately determining whether the water level in the tank 100 has dropped to the preset position above the filter media layer 100a. When the water level is higher than the preset position, the high-pressure side is immersed in the liquid phase, and the sensor outputs a corresponding liquid column pressure difference signal. When the water level drops below the filter media layer 100a, the high-pressure side is separated from the liquid phase, and the pressure difference signal changes significantly. The control unit (not shown in the figure) determines that drainage is complete and controls the positive discharge valve 1061 to close accordingly. This installation method avoids the cumulative error caused by indirect measurement, ensuring that the liquid level is accurately above the filter media layer 100a after drainage. This prevents the filter media from being lost with the water flow and its gradation from being damaged due to excessively high water levels in subsequent air washing steps, and also prevents the filter media from being exposed to the gas phase and caking due to excessively low water levels. This provides stable and reliable liquid level conditions for subsequent backwashing steps such as air washing, water washing, and combined water-air washing, ensuring the backwashing effect and the structural integrity of the filter media layer 100a.

[0042] In this embodiment, the positive discharge valve 1061 can be a solenoid valve, a pneumatic diaphragm valve, or an electric butterfly valve, all of which can form an automated control with the control unit (not shown in the figure).

[0043] In this embodiment, the control unit (not shown in the figure) can be a PLC programmable controller.

[0044] In this embodiment, the backwashing execution unit further includes an air washing module, which includes an air washing pipeline 107 connected to the bottom of the tank 100, an air washing fan 1071 connected to the air washing pipeline 107, an air inlet valve 1072 provided on the air washing pipeline 107, and an exhaust valve 1073 connected to the top of the tank 100. The control unit (not shown in the figure) is configured to: in the air washing step and the water washing combined air washing step, turn on the air washing fan 1071, the air inlet valve 1072 and the exhaust valve 1073 to introduce gas into the filter layer 100a.

[0045] In this embodiment, the purpose of setting up the air washing module is to use compressed air to agitate and fluidize the filter media layer 100a, so that the filter media particles can fully expand, suspend and rub against each other under the action of airflow, thereby effectively removing suspended matter, colloids and other impurities attached to the surface of the filter media, preventing the filter media from caking, and creating conditions for the complete removal of impurities in the subsequent water-air combined washing or water backwashing steps, thereby improving backwashing efficiency, reducing water consumption, and ensuring that the filter media layer 100a restores good filtration performance and pore structure after backwashing.

[0046] In this embodiment, the air washing blower 1071 is a Roots blower, and the end of the air washing pipeline 107 is connected to an air distribution plate (not shown in the figure). The air distribution plate (not shown in the figure) is located inside the tank 100 and laid flat below the support layer (not shown in the figure). The air distribution plate is made of stainless steel, and air distribution holes are evenly opened on the surface of the air distribution plate. The diameter of the air distribution holes is 5mm. The air washing airflow evenly penetrates upward through the support layer (not shown in the figure) and the filter layer 100a.

[0047] In this embodiment, a gas flow meter 1073 is also provided on the gas washing pipeline 107, which is used to detect the gas flow rate.

[0048] In this embodiment, the backwash execution unit further includes a backwash water inlet module, which includes a backwash water inlet pipeline 108 connected to the bottom of the tank 100, a backwash pump 1081 connected to the backwash water inlet pipeline 108, and a backwash valve 10821082 disposed on the backwash water inlet pipeline 108. The control unit (not shown in the figure) is configured to: in the water washing step and the water washing combined with air washing step, turn on the backwash pump 1081 and the backwash valve 10821082 to introduce backwash water into the tank 100.

[0049] In this embodiment, a liquid flow meter 1083 is provided on the backwash water inlet pipe 108, which is used to detect the water flow rate on the backwash water inlet pipe 108. In this way, the flow ratio of water and gas can be reasonably set in the water washing and air washing steps, thereby achieving a better cleaning effect.

[0050] In this embodiment, the backwash execution unit further includes a backwash drainage module, which includes a backwash drainage pipeline 109 connected to the tank 100 and a backwash valve 1091 disposed thereon; the control unit (not shown in the figure) is configured to: in the water washing step and the water washing combined with air washing step, open the backwash valve 1091 to discharge backwash wastewater and backwash waste gas.

[0051] In this embodiment, the installation height of the backwash drainage pipe 109 is 18-22cm higher than the upper surface of the filter layer 100a, and the internal filter screen of the backwash drainage pipe 109 is made of 304 stainless steel mesh cap, with the mesh pore size smaller than the minimum particle size of the filter material.

[0052] Accordingly, the present invention also provides a control method for an automatic backwashing filtration system, including the aforementioned automatic backwashing system, comprising: a water production step: introducing raw water into the tank 100, filtering it through the filter media layer 100a, and then entering the bottom water collection area II for water production; a monitoring step: during the water production process, detecting the turbidity of the produced water on the water production side, and detecting the operating pressure difference between the water inlet of the tank 100 and the bottom water collection area II; a triggering step: when the turbidity of the produced water ≥ a first turbidity threshold or the operating pressure difference ≥ a pressure difference threshold, initiating a backwashing program; the backwashing program includes a drainage step, a cleaning step, and a forward washing step performed sequentially; a verification step: in the forward washing step, detecting the turbidity of the backwash drainage on the drainage side, and detecting the operating pressure difference; a determination step: when the turbidity of the backwash drainage ≤ a second turbidity threshold and the operating pressure difference ≤ the pressure difference threshold, determining that the backwashing program has ended and resuming the water production step.

[0053] In this embodiment, a compensation step is also included: if the turbidity of the backwash drainage is greater than or equal to the second turbidity threshold or the operating pressure difference is greater than or equal to the pressure difference threshold, then an additional cleaning step is added, and the forward washing step and the verification step are re-executed until the turbidity of the backwash drainage is less than or equal to the second turbidity threshold and the operating pressure difference is less than or equal to the pressure difference threshold.

[0054] Please refer to Table 1 for specific backwashing procedure controls.

[0055]

[0056] Table 1

[0057] In this embodiment, the working principle of the automatic backwash filtration system is as follows: During normal filtration and water production, the control unit (not shown in the figure) opens the inlet valve 1042 and the water production valve 1051, and closes the backflow valve 1082, the air inlet valve 1072, and the backflow valve 1091. The raw water enters the top inlet area I through the inlet pipe, and after being evenly distributed by the water distribution plate, it flows through the filter media layer 100a and the support layer (not shown in the figure) to complete the filtration. The filtered clean water is produced through the water production pipeline 105. When a backwashing procedure needs to be executed, the inlet pressure differential sensor and the water production differential sensor cooperate to detect the operating pressure difference between the top inlet area I and the bottom water collection area II. The first water quality detection unit 102 collects the turbidity of the water production. When any parameter reaches a preset threshold, the control unit (not shown in the figure) starts the predetermined backwashing procedure. During the backwashing procedure, all backwashing steps are: first drain - air wash - water, then air wash - water wash - forward wash. First, close the inlet valve 1042 and the product water valve 1051, and open the forward discharge valve 1061 to lower the water level to a preset position above the filter media layer 100a. Then, turn on the air washing fan 1071, the air inlet valve 1072, and the exhaust valve 1073 to loosen the filter media with air washing. Next, turn on the backwash pump 1081, the back inlet valve 1082, and the back discharge valve 1091 to achieve combined air and water backwashing. Finally, turn off the air washing fan 1071 and the exhaust valve 1073 to perform water backwashing. Finally, turn off the backwash pump 1081 and turn on the inlet pump 1041, the inlet valve 1042, and the forward discharge valve 1061 to perform water forward washing. At the end of the backwashing stage, the second water quality detection unit 103 monitors the turbidity of the drainage in real time. The differential pressure sensor at the inlet end and the differential pressure sensor at the product water end cooperate to detect the operating pressure difference between the top inlet area I and the bottom collection area II. When the turbidity and differential pressure return to the set value, the control unit (not shown in the figure) closes all valves in the backwashing process, and after the filter media is allowed to stand, it switches to the normal filtration and product water mode.

[0058] Of course, the above describes the entire process of air washing, water washing, and combined water washing and air washing. In actual use, the second water quality detection unit 103 can monitor the turbidity of the drainage in real time, and the differential pressure sensor at the inlet end and the differential pressure sensor at the product water end can cooperate to detect whether the operating pressure difference between the top water inlet area I and the bottom water collection area II has reached the preset threshold. Then the backwashing program can be ended and the normal filtration and water production mode can be switched.

[0059] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An automatic backwashing filtration system, characterized in that, include: The tank body has a filter media layer inside; The differential pressure detection unit is used to detect the operating pressure difference between the water inlet and the bottom water collection area of ​​the tank. The first water quality testing unit is located on the product water side and is used to test the turbidity of the product water. The second water quality testing unit is located on the drainage side and is used to test the turbidity of the backwash drainage. The backwash execution unit is used to perform the backwash procedure, which includes the drainage step, the cleaning step, and the forward washing step. The control unit is connected to the differential pressure detection unit, the first water quality detection unit, the second water quality detection unit, and the backwash execution unit. During the water production process, when the turbidity of the produced water is detected to be greater than or equal to the first turbidity threshold or the operating pressure difference is detected to be greater than or equal to the pressure difference threshold, the control unit controls the backwash execution unit to start the backwash program. During the forward washing process, when the turbidity of the backwash drainage is less than or equal to the second turbidity threshold and the operating pressure difference is less than or equal to the pressure difference threshold, the control unit determines that the backwash is complete and resumes water production.

2. The automatic backwashing filtration system as described in claim 1, characterized in that, If the backwash drainage turbidity is detected to be ≥ the second turbidity threshold or the operating pressure difference is detected to be ≥ the pressure difference threshold, the control unit controls the backwash execution unit to add a cleaning step and re-execute the forward washing step until the backwash drainage turbidity is ≤ the second turbidity threshold and the operating pressure difference is ≤ the pressure difference threshold.

3. The automatic backwashing filtration system as described in claim 1, characterized in that, The cleaning steps include water washing, air washing, and a combination of water washing and air washing.

4. The automatic backwashing filtration system as described in claim 1, characterized in that, The backwash execution unit includes a drainage module, which includes a drainage pipe connected to the tank and a positive discharge valve installed on the drainage pipe. The second water quality detection unit is installed on the drainage pipe. The control unit is configured to: control the opening of the positive discharge valve before starting the backwash program to lower the water level in the tank to a preset position above the filter media layer; and receive the turbidity of the backwash drainage detected by the second water quality detection unit during the positive wash step.

5. The automatic backwashing filtration system as described in claim 3, characterized in that, The backwashing execution unit further includes an air washing module, which includes an air washing pipeline connected to the bottom of the tank, an air washing fan connected to the air washing pipeline, an air inlet valve on the air washing pipeline, and an exhaust valve connected to the top of the tank. The control unit is configured to: in the air washing step and the water washing combined air washing step, turn on the air washing fan, the air inlet valve and the exhaust valve to introduce gas into the filter layer.

6. The automatic backwashing filtration system as described in claim 3, characterized in that, The backwash execution unit further includes a backwash water inlet module, which includes a backwash water inlet pipeline connected to the bottom of the tank, a backwash pump connected to the backwash water inlet pipeline, and a backwash valve located on the backwash water inlet pipeline. The control unit is configured to: in the water washing step and the water washing combined with air washing step, turn on the backwash pump and the backwash valve to introduce backwash water into the tank.

7. The automatic backwashing filtration system as described in claim 3, characterized in that, The backwash execution unit further includes a backwash drainage module, which includes a backwash drainage pipeline connected to the tank and a backwash valve disposed thereon; the control unit is configured to: in the water washing step and the water washing combined with air washing step, open the backwash valve to discharge backwash wastewater and backwash waste gas.

8. The automatic backwashing filtration system as described in claim 4, characterized in that, It also includes a water inlet module that is signal-connected to the control unit. The water inlet module includes a water inlet pipe that is connected to the water inlet end of the tank, a water inlet pump that is connected to the water inlet pipe, and a water inlet valve that is located on the water inlet pipe.

9. The automatic backwashing filtration system as described in claim 8, characterized in that, It also includes a water production module connected to the control unit. The water production module includes a water production pipeline connected to the bottom water collection area and a water production valve located on the water production pipeline. The first water quality detection unit is located on the water production pipeline. The control unit is configured to: during the water production process, turn on the water inlet pump, the water inlet valve, and the water production valve to introduce raw water into the tank and produce filtered water through the filter media layer; when the turbidity of the produced water is greater than or equal to a first turbidity threshold or the operating pressure difference is greater than or equal to a pressure difference threshold, close the water inlet valve and the water production valve.

10. The automatic backwashing filtration system as described in claim 8, characterized in that, The backwash execution unit also includes a forward wash module, which includes the water inlet module and the forward drain valve in the drainage module; the control unit is configured to: in the forward wash step, turn on the water inlet pump, the water inlet valve and the forward drain valve to introduce raw water into the tank for forward wash.

11. A control method for an automatic backwashing filtration system, comprising a tank and a filter media layer located within the tank, characterized in that, include: Water production steps: Raw water is introduced into the tank, filtered through the filter media layer, and then enters the bottom water collection area for water production; Monitoring steps: During the water production process, the turbidity of the produced water on the production side is detected, and the operating pressure difference between the water inlet of the tank and the bottom water collection area is detected; Triggering steps: When the turbidity of the produced water is detected to be greater than or equal to the first turbidity threshold or the operating differential pressure is detected to be greater than or equal to the differential pressure threshold, the backwashing procedure is started; The backwashing procedure includes a drainage step, a cleaning step, and a forward washing step performed sequentially. Verification steps: In the forward washing step, the turbidity of the backwash drainage on the drainage side is detected, and the operating pressure difference is also detected; Judgment Step: When the turbidity of the backwash drainage is ≤ the second turbidity threshold and the operating pressure difference is ≤ the pressure difference threshold, the backwashing process is determined to be completed and the product water step is restored.

12. The control method as described in claim 11, characterized in that, It also includes a compensation step: if the backwash drainage turbidity is detected to be ≥ the second turbidity threshold or the operating pressure difference is detected to be ≥ the pressure difference threshold, then an additional cleaning step is added, and the forward washing step and the verification step are re-executed until the backwash drainage turbidity is detected to be ≤ the second turbidity threshold and the operating pressure difference is detected to be ≤ the pressure difference threshold.

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