A method of backwashing a filter device using electromagnetic regulation-based control

Abstract

The application discloses a method of backwashing filter device based on electromagnetic control, which comprises a filter tank shell, a composite filter layer arranged in the filter tank shell, and an electromagnetic system, wherein the composite filter layer comprises magnetic filter material and non-magnetic filter material; the electromagnetic system comprises an electromagnet generator and a magnetic field generating unit arranged around the filter tank shell; the magnetic field generating unit comprises a plurality of electromagnet cores and coils wound around the electromagnet cores; the electromagnet generator is electrically connected with the coils through wires and provides direct current or alternating current to the coils. In the backwashing stage, the alternating action of the direct current and alternating current magnetic field guides the spatial reconstruction or micro-vibration of the magnetic filter material, thereby enhancing the filter layer flushing effect and improving the backwashing efficiency. The device realizes low energy consumption, low water consumption and high efficiency backwashing, and has the advantages of compact structure, high automation degree and strong adaptability, and is suitable for the solid-liquid separation process of mine dewatering water, industrial circulating water and sewage treatment.

Description

A method using an electromagnetically controlled backwashing filtration device Technical Field

[0001] This invention relates to the field of water treatment equipment technology, and in particular to a method using an electromagnetically controlled backwashing filtration device for solid-liquid separation and filtration systems in industrial circulating water, mine drainage water, and sewage treatment. Background Technology

[0002] In the process of treating mine drainage water, the water contains a large number of suspended particles, colloids and impurities, which can easily lead to pipeline blockage, reduced heat exchange efficiency or equipment corrosion. Therefore, filters, mechanical filters or multi-media filters are usually installed in the water treatment system to remove suspended solids. Existing traditional filtration equipment mainly uses quartz sand or anthracite as filter media and achieves solid-liquid separation through gravity filtration. When the filter layer is contaminated and blocked, it is necessary to remove impurities by backwashing in order to restore filtration performance. However, the existing technology has the following problems: (1) The filter layer is prone to clumping and backwashing is incomplete: Conventional backwashing only relies on reverse water flow to flush, the filter media gap is small and the resistance is large, impurities are easily retained, and the backwashing effect is poor. (2) High energy consumption and high water consumption: In order to achieve the ideal flushing effect, it is necessary to increase the backwashing flow rate and pressure, which leads to a significant increase in energy consumption and water consumption. (3) Short filter media life: Frequent high-intensity backwashing can easily cause filter media wear and loss, affecting service life.

[0003] To address the aforementioned issues, how to improve backwashing efficiency, reduce energy consumption, and extend filter media lifespan while ensuring filtration accuracy has become a key problem that current technology urgently needs to solve. Summary of the Invention

[0004] To address the common problems of poor backwashing effect, easy wear and tear of filter media, and high operating energy consumption in existing filtration equipment, this invention provides a backwashing filtration device and method based on electromagnetic control. This device utilizes electromagnetic control technology to precisely adjust the structure and movement of the filter media, thereby significantly improving the backwashing effect, reducing operating energy consumption, and extending the service life of the filter media. This invention is particularly applicable to solid-liquid separation processes such as mine drainage, industrial circulating water, and wastewater treatment, and is of great significance for improving the cleaning effect and filtration accuracy of filter media.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, there is an electromagnetically controlled backwashing filtration device, the backwashing filtration device comprising a filter tank shell, a composite filter layer disposed within the filter tank shell, and an electromagnetic system, wherein:

[0007] The composite filter layer includes magnetic filter media and non-magnetic filter media;

[0008] The electromagnetic system includes an electromagnet generator and a magnetic field generating unit surrounding the filter canister; the magnetic field generating unit includes several electromagnet cores and a coil wound around the electromagnet cores; the electromagnet generator is electrically connected to the coil via a wire and provides it with direct current or alternating current.

[0009] The present invention is further configured such that the backwashing filter device includes an outer shell sleeved on the outside of the filter tank shell, a hollow interlayer is formed between the outer shell and the filter tank shell, and the magnetic field generating unit is disposed in the hollow interlayer.

[0010] The present invention is further configured such that the electromagnet cores are uniformly distributed within the hollow interlayer, and adjacent electromagnet cores are interconnected through a magnetic guide to form a closed magnetic circuit, so as to ensure the uniformity and stability of the magnetic field distribution.

[0011] The present invention is further configured such that the coil adopts an interleaved wiring pattern to reduce eddy current losses and improve the magnetic field response speed.

[0012] The present invention is further configured such that the mixing volume ratio of the magnetic filter material to the non-magnetic filter material is 1:1 to 3:1.

[0013] The present invention is further configured such that the magnetic filter material is a soft magnetic material that can be repeatedly magnetized, selected from one or more of magnetite, ferrite and ceramic microspheres coated with magnetic alloy.

[0014] The present invention is further configured such that the non-magnetic filter material is selected from one or more of quartz sand, anthracite, and ceramsite.

[0015] The present invention is further configured such that a filter screen is provided below the composite filter layer to support the filter material and prevent the filter material from being lost.

[0016] Secondly, the method using the aforementioned electromagnetically controlled backwashing filter includes the following steps:

[0017] S1 backwash start-up phase:

[0018] When the filtration resistance rises to the set threshold or when cleaning is automatically determined based on the running time, the backwash filter enters the backwash mode; the electromagnet generator is started and DC power is applied. Under the action of the DC magnetic field, the magnetic filter media are arranged along the direction of the magnetic lines of force to form a magnetic chain structure, the filter layer volume expands, and the porosity increases significantly; at this time, the backwash water penetrates the composite filter layer from bottom to top, flushing and carrying away the trapped impurities.

[0019] S2 backwashing enhancement stage:

[0020] When the pressure difference inside the filter layer drops to the preset value, the electromagnet generator switches to AC power. In AC magnetic field mode, due to the periodic change of the alternating magnetic field, the magnetic filter material vibrates slightly, causing relative motion between it and the non-magnetic filter material, forming a "stirring" cleaning effect, thereby further removing attached pollutants and improving the cleaning effect.

[0021] S3 reset phase:

[0022] After backwashing, turn off the electromagnet generator. The magnetic field disappears, the magnetic filter media loses its magnetic attraction, and it naturally falls back with the non-magnetic filter media under the action of gravity, reforming a dense composite filter layer and restoring the filtration state.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) This invention innovatively employs a controllable electromagnetic field to dynamically adjust the structure and movement of the filter media. In traditional filtration equipment, the backwashing process relies on the reverse scouring of water flow, which often fails to effectively remove fine impurities from the filter media and easily leads to accumulation, clumping, or wear of the filter media. However, this application, through precise control of the electromagnetic field, can adjust the spatial arrangement and dynamic behavior of the magnetic filter media as needed during filtration and backwashing, thereby effectively optimizing the cleaning effect of the filter media, improving backwashing efficiency, and avoiding the retention of deposits on the surface of the filter media.

[0025] (2) In the backwashing stage, this invention guides the magnetic filter media to undergo spatial reconstruction or micro-vibration through the alternating action of DC and AC magnetic fields of the electromagnetic system. Under the DC magnetic field, the magnetic filter media aligns along the magnetic field lines to form magnetic chains similar to floating internal components, causing the filter layer to become loose and the pores to expand, thus significantly enhancing the flowability of the backwashing channel. Under the action of the AC magnetic field, the micro-vibration effect generated by the magnetic filter media enables the particles between the filter media to collide and rub against each other, thereby effectively removing sludge, colloids, and fine suspended matter attached to the surface of the filter media, enhancing the thoroughness of backwashing. This dual action makes the cleaning of the filter media more uniform and efficient, avoiding the problem of impurity residue in traditional backwashing methods.

[0026] (3) Low energy and water consumption. The magnetic expansion and micro-vibration assisted cleaning mechanism significantly reduces the backwash water flow rate and pressure required to achieve the ideal cleaning effect, thereby greatly saving energy and rinsing water consumption, which meets the requirements of energy conservation and environmental protection. Attached Figure Description

[0027] Figure 1 is a schematic diagram of the overall structure of the backwashing filter device based on electromagnetic control according to the present invention.

[0028] Figure 2 is a schematic diagram of the internal structure of the backwashing filter device based on electromagnetic control of the present invention (without power).

[0029] Figure 3A and Figure 3B are schematic diagrams of the disassembled outer shell and filter tank shell, respectively.

[0030] Figure 4 is a schematic diagram of the electromagnet core arrangement.

[0031] Figure 5 is a schematic diagram of a coil wound around an electromagnet core.

[0032] Figure 6A and Figure 6B are respectively the arrangement diagrams of the filter media before and after energization of the electromagnetically controlled backwashing filter device of the present invention.

[0033] In the diagram: Filter tank shell 1; Media inlet 11; Media outlet 12; Backwash inlet 13; Backwash outlet 14; Discharge port 15; Feed inlet 16; Composite filter layer 2; Magnetic filter media 21; Non-magnetic filter media 22; Electromagnet generator 3; Electromagnet core 31; Coil 32; Outer shell 4; Circular structure 41; Filter screen 5; Support leg 6. Detailed Implementation

[0034] 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] As shown in Figures 1-4, the electromagnetically controlled backwashing filtration device of the present invention includes a filter tank 1, a composite filter layer 2 disposed within the filter tank 1, and an electromagnetic system. The composite filter layer 2 includes magnetic filter material 21 and non-magnetic filter material 22 (see Figure 6). The electromagnetic system includes an electromagnet generator 3 and a magnetic field generating unit surrounding the filter tank 1. Referring to Figure 5, the magnetic field generating unit includes several electromagnet cores 31, each of which is uniformly wound with multiple turns of enameled copper wire to form a coil 32. The electromagnet generator 3 is electrically connected to the coil 32 via a wire and provides it with direct current or alternating current, and controls the direction, intensity, and waveform of the current.

[0036] When the electromagnet generator 3 is powered on, the coil 32 generates a circumferential magnetic field around the electromagnet core 31. This magnetic field passes through the filter canister 1 and acts on the magnetic filter material 21 in the internal composite filter layer 2, thereby realizing the spatial reconstruction and flow control of the magnetic filter material 21.

[0037] The backwashing filtration device also includes an outer shell 4 fitted over the outside of the filter tank shell 1, forming a hollow interlayer between the outer shell 4 and the filter tank shell 1. The magnetic field generating unit is disposed within the hollow interlayer. The filter tank shell 1 and the outer shell 4 are preferably made of steel, possessing good mechanical strength and pressure resistance. The hollow interlayer is supported by an upper circular structure 41 and fixedly connected to the filter tank shell 1. A support leg 6 is also provided at the bottom of the outer shell 4 for support and installation fixation.

[0038] The electromagnet cores 31 are uniformly distributed within the hollow interlayer, and adjacent electromagnet cores 31 are interconnected through a magnetic guide (not shown in the figure) to form a closed magnetic circuit, ensuring the uniformity and stability of the magnetic field distribution. The coils 32 employ staggered wiring to reduce eddy current losses and improve the magnetic field response speed.

[0039] The outer shell 4 is also provided with a media inlet 11, a media outlet 12, a backwash inlet 13, a backwash outlet 14, a discharge port 15, and a feed port 16 that communicate with the inside of the filter tank shell 1, for realizing the switching of media flow and the loading and unloading of filter media during the filtration and backwashing process.

[0040] In the composite filter layer 2, the mixing volume ratio of magnetic filter media 21 to non-magnetic filter media 22 is 1:1 to 3:1, which can be flexibly adjusted according to the suspended solids concentration and particle size in the influent water. An appropriate amount of magnetic filter media 21 ensures the filter layer has adjustable porosity and strong agitation capability, while an appropriate amount of non-magnetic filter media 22 prevents magnetic agglomeration that could lead to filter layer hardening. If too much magnetic filter media 21 is used, or if all of it is used, under the influence of a magnetic field, the tightly connected ends of the magnetic filter media 21 can easily form hard magnetic chains or clusters, leading to excessive compaction or "magnetized hardening" of the filter layer. This structure will transform the filter layer from a loose state into a rigid, dense solid network, creating fluid dead zones and causing a significant increase in pressure drop. Therefore, a certain proportion of non-magnetic filter media 22 must be mixed in to maintain the stability and unobstructed flow of the filter layer structure.

[0041] The magnetic filter media 21 is a soft magnetic material that can be repeatedly magnetized, such as magnetite, ferrite, and ceramic microspheres coated with magnetic alloys. It has the characteristics of repeated magnetization, low remanence, and fast response. The non-magnetic filter media 22 can be conventional media such as quartz sand, anthracite, and ceramsite to form a composite pore structure.

[0042] Below the composite filter layer 2, a filter screen 5 is also provided to support the filter material and prevent it from being lost. The filter screen 5 adopts a stainless steel screen structure with a pore size range of 50~200µm, which can effectively trap fine suspended particles.

[0043] As shown in Figure 6, during the filtration stage, the electromagnet generator 3 is not energized, and the magnetic filter media 21 and non-magnetic filter media 22 are uniformly mixed. In the initial stage of backwashing, the electromagnet generator 3 uses DC power supply. The magnetic filter media 21, under the influence of the magnetic field, aligns along the magnetic lines of force to form magnetic chains similar to floating internal components, expanding the gaps between the filter media and facilitating backwashing. Simultaneously, the rigid chain network formed by the magnetic chains maintains a stable pore structure within the composite filter layer 2, preventing pressure drop spikes caused by dust blockage. In the later stage of backwashing, the electromagnet generator 3 switches to AC power mode, using an alternating magnetic field to induce micro-vibrations in the magnetic filter media 21, promoting mutual friction between the filter media and thus enhancing the removal and cleaning effect of attached particles. The output time of the electromagnet generator 3 for both DC and AC power can be adjusted according to the actual contamination level of the material. When contamination is severe, the DC power stage time can be increased; while when high cleaning precision is required, the AC power stage time can be appropriately extended.

[0044] The method using the above-mentioned electromagnetically controlled backwashing filter includes the following steps:

[0045] S1 Filtering Stage:

[0046] When the device is in the filtration stage, the media inlet 11 and media outlet 12 are open, the backwash inlet 13 and backwash outlet 14 are closed, the electromagnet generator 3 is closed, there is no magnetic field inside the filter tank 1, and the magnetic filter media 21 and non-magnetic filter media 22 naturally accumulate under the action of gravity to form a dense composite filter layer 2; the liquid to be treated enters the filter tank 1 through the media inlet 11 and passes through the composite filter layer 2 from top to bottom. Suspended solids are trapped above the filter layer or in the gaps between the filter media, and the purified liquid is discharged from the media outlet 12; after long-term operation, the gaps in the filter layer are gradually blocked by suspended particles, and the filtration pressure difference increases.

[0047] S2 backwash start-up phase:

[0048] When the filtration differential pressure rises to the set threshold or the system automatically determines that cleaning is required based on the running time, the system enters the backwashing stage. The media inlet 11 and media outlet 12 are closed, and the backwash inlet 13 and backwash outlet 14 are opened. At the same time, the electromagnet generator 3 is started and DC power is supplied. Under the action of the DC magnetic field, the magnetic filter media 21 is arranged along the direction of the magnetic lines of force to form a magnetic chain structure. The volume of the composite filter layer 2 expands and the porosity increases significantly. At this time, the backwash water enters through the backwash inlet 13, penetrates the composite filter layer 2 from bottom to top, washes away and carries away the trapped impurity particles, and is discharged from the backwash outlet 14.

[0049] S3 Backwashing Enhancement Stage:

[0050] When the filtration differential pressure drops to the preset value, the electromagnet generator 3 switches to AC power. In AC magnetic field mode, due to the periodic changes of the alternating magnetic field, the magnetic filter media 21 vibrates slightly, causing relative motion between it and the non-magnetic filter media 22, creating a "stirring" cleaning effect. This further removes attached contaminants and improves the cleaning effect. This micro-scale oscillation can effectively remove fine sludge, oil film, and colloidal substances attached to the surface of the filter media, making backwashing more thorough.

[0051] S4 reset phase:

[0052] After backwashing is completed, the electromagnet generator 3 is turned off, the magnetic field disappears, the magnetic filter material 21 loses its magnetic attraction, and it naturally falls back with the non-magnetic filter material 22 under the action of gravity and reforms into a dense composite filter layer 2, restoring the filtration state.

[0053] Backwashing effect test

[0054] This invention verifies the electromagnetic control method of the aforementioned electromagnetically controlled backwashing filter device and the influence of the mixed filter media ratio on the backwashing effect through the following comparative tests. All test cases were conducted under the same backwashing filter differential pressure (contamination level), backwash water flow rate, pressure, and duration. During electromagnetic control, the current direction, intensity, and waveform were all identical.

[0055] Test conditions settings:

[0056] Test Group A (Full Magnetic + Electromagnetic Control): The filter media is 100% magnetic magnetite. The electromagnetic control program is activated during backwashing (DC first, then AC).

[0057] Test Group B (Mixed + Electromagnetic Control): The filter media is a 1:1 volume mixture of magnetite and quartz sand. The same electromagnetic control program as Test Group A is used during backwashing.

[0058] Test group C (mixed + DC): The filter media is a 1:1 volume ratio of magnetite and quartz sand, and only a DC magnetic field is used during backwashing.

[0059] Test group D (mixed + AC): The filter media is a 1:1 volume mixture of magnetite and quartz sand, and only an AC magnetic field is used during backwashing.

[0060] Test Group E (Mixed + Traditional Backwash): The filter media is a 1:1 volume mixture of magnetite and quartz sand. During backwashing, the electromagnetic system is turned off, and only hydraulic backwashing is performed.

[0061] Test methods and results:

[0062] The test was conducted using the aforementioned method. The core measurement indicator was the initial filtration pressure differential after the system recovered its filtration state following backwashing and settling. A lower value indicates better filter bed cleaning and structural recovery. The test data is recorded in Table 1 below:

[0063] Table 1

[0064]

[0065] Results analysis:

[0066] Comparing test groups B through E, it is evident that, with the same proportion of mixed filter media, the filtration pressure difference after using the electromagnetically controlled backwashing of this invention (Group B) is significantly lower than that of traditional hydraulic backwashing (Group E). While backwashing using a direct current magnetic field (Group C) or an alternating current magnetic field (Group D) is superior to traditional hydraulic backwashing (Group E), it is far inferior to the electromagnetically controlled backwashing of this invention (Group B). This is because using only a direct current magnetic field cannot effectively remove contaminants firmly attached to the filter media surface, easily forming fixed channels and leading to uneven cleaning. Using only an alternating current magnetic field results in a limited increase in filter layer porosity, and the backwash water flow resistance remains high. Contaminants dislodged by vibration may not be effectively carried out by the water flow, easily causing "secondary retention," resulting in low backwashing efficiency and high water consumption. This demonstrates that the alternating control method of direct and alternating current magnetic fields can effectively improve the cleaning effect of the filter layer.

[0067] Comparing test groups A and B, it can be seen that under the same electromagnetic control program, the filtration pressure difference after backwashing using 1:1 mixed filter media (group B) is much lower than that using all-magnetic filter media (group A). ​​This is because using only magnetic filter media would lead to excessive compaction and "magnetization and caking" of the filter layer in the magnetic field, which is actually detrimental to cleaning; while incorporating non-magnetic filter media can effectively maintain the stability and unobstructed pore structure of the filter layer, which is a necessary condition to ensure the effectiveness of electromagnetic control.

[0068] In summary, the test results fully demonstrate that the present invention, which uses mixed filter media and combines it with an electromagnetic control backwashing method that first uses DC and then AC, can work synergistically to achieve the optimal backwashing effect.

[0069] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method using an electromagnetically controlled backwashing filtration device, characterized in that, The method employs an electromagnetically controlled backwashing filtration device. The backwashing filtration device includes a filter tank, a composite filter layer disposed within the filter tank, and an electromagnetic system. The composite filter layer includes magnetic and non-magnetic filter media. The electromagnetic system includes an electromagnet generator and a magnetic field generating unit surrounding the filter tank. The magnetic field generating unit includes several electromagnet cores and coils wound around the electromagnet cores. The electromagnet generator is electrically connected to the coils via wires and provides them with direct current or alternating current. The method includes the following steps: S1 Backwashing Start-up Stage: When the filtration resistance rises to a set threshold or cleaning is automatically determined based on the running time, the backwashing filtration device enters backwashing mode. The electromagnet generator is started and direct current is applied. Under the action of a DC magnetic field, the magnetic filter media aligns along the magnetic lines of force to form a magnetic chain structure, causing the filter layer to expand in volume and significantly increase its porosity. At this time, backwash water penetrates the composite filter layer from bottom to top, flushing away and carrying away the trapped impurities. S2 Backwashing Enhancement Stage: When the pressure difference inside the filter layer drops to the preset value, the electromagnet generator switches to AC power. In AC magnetic field mode, due to the periodic changes of the alternating magnetic field, the magnetic filter media vibrates slightly, causing relative motion between it and the non-magnetic filter media, forming a "stirring" cleaning effect, thereby further removing attached pollutants and improving the cleaning effect. S3 Reset Stage: After backwashing, the electromagnet generator is turned off, the magnetic field disappears, the magnetic filter media loses its magnetic attraction, and naturally falls back with the non-magnetic filter media under the action of gravity, reforming a dense composite filter layer and restoring the filtration state.

2. The method of using an electromagnetically controlled backwashing filtration device according to claim 1, characterized in that, The backwashing filter device also includes an outer shell fitted outside the filter tank shell, with a hollow interlayer formed between the outer shell and the filter tank shell, and the magnetic field generating unit disposed within the hollow interlayer.

3. The method of using an electromagnetically controlled backwashing filtration device according to claim 2, characterized in that, The electromagnet cores are evenly distributed within the hollow interlayer, and adjacent electromagnet cores are interconnected through magnetic guide supports to form a closed magnetic circuit.

4. The method of using an electromagnetically controlled backwashing filter according to claim 1, characterized in that, The coil uses an interleaved wiring method.

5. The method of using an electromagnetically controlled backwashing filter according to claim 1, characterized in that, The mixing volume ratio of the magnetic filter material to the non-magnetic filter material is 1:1 to 3:

1.

6. The method of using an electromagnetically controlled backwashing filtration device according to claim 1, characterized in that, The magnetic filter material is a soft magnetic material that can be repeatedly magnetized, selected from one or more of magnetite, ferrite, and ceramic microspheres coated with magnetic alloys.

7. The method of using an electromagnetically controlled backwashing filter according to claim 1, characterized in that, The non-magnetic filter material is selected from one or more of quartz sand, anthracite, and ceramsite.

8. The method of using an electromagnetically controlled backwashing filter according to claim 1, characterized in that, A filter screen is also provided below the composite filter layer.

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