A gas filtration device and method with self-adjusting porosity

Abstract

This invention discloses a gas filtration device and method with self-adjusting porosity. The gas filtration device includes a gas pretreatment device, a spacing adjustment component, a particle state detection unit, an axial compression mechanism, and an adjustable filter assembly. The gas pretreatment device is used to change the particle state in the gas. The adjustable filter assembly includes a housing and an internal compression chamber. A compressible filter medium is arranged axially within the compression chamber, and isolation discs are arranged between adjacent filter media to form a segmented confined structure, creating radial limiting within the confined space of the housing to suppress axial migration of the filter medium during repeated adjustment. The filter medium is an open-pore porous material with elastic deformation capability, capable of elastic reset after the axial force is released. The particle state detection unit can detect the state of the filtered gas and control the axial compression mechanism to apply an overall axial force to the adjustable filter assembly based on the detection result, so that the pore structure of the filter medium matches the state of the gas particles.

Description

Technical Field

[0001] This invention belongs to the field of gas filtration technology, specifically relating to a gas filtration device and method with self-adjusting porosity. Background Technology

[0002] Gas filtration devices are widely used in industrial waste gas treatment, dust control, and other fields, relying on the pore structure of the filter media to intercept particulate matter. Existing devices mostly use metal mesh, fiber filter media, or porous ceramics, whose porosity and pore size distribution are fixed, making it difficult to adapt to continuous fluctuations in the concentration, size, and flow rate of particulate matter in the gas. When filtration requirements change, the filter media must be replaced or operating conditions adjusted, increasing maintenance costs and failing to meet the rapid response requirements for continuous operation.

[0003] Some technologies attempt to adjust filtration performance through mechanical compaction, but these often involve unilateral or localized pressure application, easily leading to uneven pore distribution and localized over-compaction of the filter media, affecting filtration efficiency and stability. Other technologies pre-treat the particle state before filtration, but fail to effectively link this pre-treatment to the adjustment of the filter structure. The filter structure remains fixed or relies on manual adjustment, lacking real-time responsiveness, resulting in fluctuating filtration efficiency and shortened filter media lifespan. These shortcomings are particularly pronounced in scenarios with variable operating conditions and large fluctuations in particle load. Existing technologies still require an adaptive pore size adjustment scheme for the filter media based on particle state. Summary of the Invention

[0004] This invention provides a gas filtration device and method with self-adjusting porosity.

[0005] In a first aspect, the present invention provides a gas filtration device with self-adjusting porosity, comprising an outer frame and a gas pretreatment device and an adjustable filter assembly installed inside the outer frame; the gas pretreatment device is used to pretreat the gas to be filtered by electrolysis; the adjustable filter assembly is used to further filter the pretreated gas using a filter medium.

[0006] The adjustable filter assembly includes a housing and a compression chamber installed inside the housing; the compression chamber includes an upper partition, a lower partition, and multiple accordion-style compression bladders between the upper and lower partitions for storing different filter media; the accordion-style compression bladders are axially stacked along the gas flow direction, and the porosity of the filter media stored in the accordion-style compression bladders decreases along the gas flow direction; adjacent accordion-style compression bladders are isolated by an isolation disc;

[0007] The gas filtration device also includes an axial compression mechanism; the axial compression mechanism is used to adjust the position of the upper and lower partitions to control the porosity of the filter medium in the bellows-type compression airbag.

[0008] Preferably, the gas pretreatment device electrolyzes the gas to be filtered using porous conductive components and needle-shaped conductive components.

[0009] Preferably, the device also includes a control unit and a particle state detection unit; the particle state detection unit is used to detect the particle size of the gas particles filtered by the adjustable filter assembly; the gas pretreatment device also includes a particle sensor; the particle sensor is used to monitor the particle size and particle concentration of the pretreated gas particles; the particle state detection unit is used to adjust the distance between the porous conductive component and the needle-shaped conductive component, as well as the positions of the upper and lower partitions, according to the particle size and particle concentration of the pretreated gas particles and the particle size of the filtered gas particles.

[0010] Preferably, the device also includes a spacing adjustment component; the spacing adjustment component drives the needle-shaped conductive component to move horizontally under the action of a servo motor through a sliding pair consisting of a slider and a lead screw, thereby controlling the distance between the porous conductive component and the needle-shaped conductive component.

[0011] Preferably, the outer edge of the isolation disc is fixed to the inner wall of the housing; the axial compression mechanism controls the movement distance of the upper and lower partitions respectively, so that the filter media in the two outermost accordion-type compression airbags reach their corresponding set porosity.

[0012] Preferably, the axial compression mechanism includes a fixed base and a cylinder, a piston rod, and a second servo motor mounted on the fixed base; the axial compression mechanism drives the piston rod to move linearly in the cylinder through the second servo motor, thereby adjusting the positions of the upper and lower partitions.

[0013] Secondly, the present invention provides a gas filtration method with self-adjusting porosity, which employs the aforementioned gas filtration device; the gas filtration method includes:

[0014] The filter medium and the preset distance between the porous conductive component and the needle-shaped conductive component are determined based on the gas to be filtered; the filter medium is stored in different bellows-type compressed air bags according to its initial porosity; the gas to be filtered is passed into a gas pretreatment device for pretreatment, and the pretreated gas is input into an adjustable filter assembly for filtration.

[0015] Preferably, during the gas filtration process, the particle size of the gas filtered by the adjustable filter assembly is detected, and the distance between the porous conductive component and the needle-shaped conductive component is adjusted based on the particle size; the particle concentration and particle size of the pretreated gas after the distance adjustment are detected, and the porosity of the filter medium is adjusted based on the particle concentration and particle size; the above process is repeated until the particle size of the filtered gas meets the preset conditions.

[0016] Preferably, the porosity adjustment method is as follows: obtaining the target compression stroke based on particle concentration and particle size; if the target compression stroke is greater than the maximum allowable compression stroke threshold, obtaining the target spacing between the porous conductive component and the needle-shaped conductive component based on the target compression stroke; adjusting the gas pretreatment device using the target spacing as the control adjustment amount of the spacing adjustment component; repeating the above process until the target compression stroke is less than the maximum allowable compression stroke threshold; applying corresponding axial forces to the upper and lower partitions respectively based on the target compression stroke to independently adjust the porosity of different filter media.

[0017] Preferably, the gas to be filtered is ammonia; the filter medium is an open-cell polyurethane elastic foam and an expanded polytetrafluoroethylene elastic porous membrane.

[0018] The beneficial effects of this invention are:

[0019] 1. This invention stores the filter medium by axially stacking multiple bellows-type compressed airbags along the gas flow direction, and dynamically adjusts the filter porosity by adjusting the bellows-type compressed airbags through an axial compression mechanism, thereby improving filtration stability and adaptability. At the same time, this invention uses a spacing adjustment component to adjust the spacing between porous conductive components and needle-shaped conductive components, thereby better modulating the charge, distribution and aggregation state of gas particles.

[0020] 2. This invention uses the state of gas particles as the basis for adjusting the gas pretreatment device and the adjustable filter component, realizing the overall, coordinated, and adaptive adjustment of the pore structure of the filter medium, thereby improving the stability of the filtration process. At the same time, this invention constructs a fully closed-loop system of "pretreatment - particle detection - compression adjustment - stroke feedback - pretreatment readjustment" through the linkage of displacement sensor and gas pretreatment device, which adaptively responds to drastic fluctuations in operating conditions, further improving filtration efficiency and stability, while avoiding the problems of excessive filtration resistance and increased energy consumption caused by over-compression. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the gas pretreatment device in Embodiment 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of the spacing adjustment component in Embodiment 1 of the present invention.

[0024] Figure 4 This is a schematic diagram of the adjustable filter component in Embodiment 1 of the present invention.

[0025] Figure 5 This is a schematic diagram of the compression chamber in Embodiment 1 of the present invention.

[0026] Figure 6 This is a schematic diagram of the axial compression mechanism in Embodiment 1 of the present invention.

[0027] Figure 7 This is an overall flowchart of Embodiment 2 of the present invention.

[0028] Reference numerals: 1. Outer frame; 2. Gas pretreatment device; 3. Spacing adjustment component; 4. Adjustable filter component; 5. Axial compression mechanism; 2-1. Sealing chamber; 2-2. Support plate; 2-3. Porous conductive component; 2-4. Needle-shaped conductive component; 2-5. Drive motor; 2-6. Particle sensor; 3-1. Base; 3-2. Slide rail; 3-3. Lead screw; 3-4. Slider; 3-5. Fixing component; 3-6. Servo motor; 4-1. Housing; 4-2. Compression chamber; 4-3. Upper partition; 4-4. Lower partition; 4-5. Bellows-style compression airbag; 4-6. Isolation disc; 4-7. Displacement sensor; 5-1. Fixing seat; 5-2. Cylinder; 5-3. Piston rod; 5-4. Second servo motor. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] Example 1

[0031] like Figure 1 As shown, a gas filtration device with self-adjusting porosity includes an outer frame 1 and a gas pretreatment device 2, a spacing adjustment component 3, an adjustable filter component 4, an axial compression mechanism 5, a particle state detection unit, and a control unit installed inside the outer frame 1. The gas pretreatment device 2 is used to pretreat the gas to be filtered by arc electrolysis and to detect the state of the pretreated gas. The spacing adjustment component 3 is used to adjust the treatment effect of the gas pretreatment device 2 on the filtered gas. The adjustable filter component 4 is used to further filter the pretreated gas using filter media with different porosities. The axial compression mechanism 5 is used to adjust the porosity of the filter media in the adjustable filter component 4. The particle state detection unit is used to detect the particle size of the gas particles filtered by the adjustable filter component 4.

[0032] In this embodiment, the filter medium is an open-pore porous material with elastic deformation capability, which can elastically reset after the axial force is released, so as to maintain the reversibility of the pore structure change.

[0033] like Figure 2As shown, the gas pretreatment device 2 includes a sealed chamber 2-1, a support plate 2-2, a porous conductive component 2-3, a needle-shaped conductive component 2-4, a drive motor 2-5, and a particle sensor 2-6. The sealed chamber 2-1 has a hollow cylindrical structure with an inlet and an outlet. The inlet of the sealed chamber 2-1 is used to introduce the gas to be filtered, and the outlet is used to output the filtered gas to the inlet of the adjustable filter assembly 4 through a gas delivery pipe. The support plate 2-2 is nested on the circular tube 2-1 to provide support for the circular tube 2-1. Both the porous conductive component 2-3 and the needle-shaped conductive component 2-4 are disposed inside the circular tube 2-1, and the outer edge of the porous conductive component 2-3 is tightly fitted to the inner wall of the circular tube 2-1. The drive motor 2-5 is connected to the needle-shaped conductive member 2-4 via a coupling and a conductive slip ring, and is used to drive the needle-shaped conductive member 2-4 to rotate. By continuously applying a negative current to the needle-shaped conductive member 2-4, the rotating needle-shaped conductive member 2-4 (negative pole) generates an electric arc with the porous conductive member 2-3 (positive pole). The electric arc decomposes the gas for pretreatment, thereby modulating the charge, distribution, and aggregation state of the gas particles. The particle sensor 2-6 is used to monitor the particle size and particle concentration of the gas particles.

[0034] In this embodiment, the sealed chamber 2-1 is made of acrylic tubing; the support plate 2-2 is made of mica board.

[0035] like Figure 3 As shown, the spacing adjustment assembly 3 includes a base 3-1 and a slide rail 3-2, a lead screw 3-3, a slider 3-4, a fixing member 3-5, and a servo motor 3-6 mounted on the base 3-1. The slide rail 3-2 and the lead screw 3-3 are arranged side by side on the base 3-1, and both ends of the lead screw 3-3 are supported by the fixing member 3-5. The slider 3-4 is mounted on the slide rail 3-2 and the lead screw 3-3, and is supported and has the power for horizontal sliding through the slide rail 3-2 and the lead screw 3-3, respectively. The servo motor 3-6 is connected to one end of the lead screw 3-3 through a coupling. By driving the rotation of the lead screw 3-3, the servo motor 3-6 drives the slider 3-4 to slide laterally along the slide rail 3-2, thereby adjusting the position of the drive motor 2-5 fixed on the slider 3-4 and controlling the distance between the porous conductive member 2-3 and the needle-shaped conductive member 2-4.

[0036] like Figure 4 and Figure 5As shown, the adjustable filter assembly 4 includes a housing 4-1 and a compression chamber 4-2 installed inside the housing 4-1. The housing 4-1 consists of an upper housing and a lower housing. The upper and lower housings are fixed together by bolts and nuts, facilitating the disassembly and installation of the components inside the housing 4-1. The compression chamber 4-2 includes an upper partition 4-3, a lower partition 4-4, and two accordion-type compression chambers 4-5 axially stacked between the upper and lower partitions along the gas flow direction. The two accordion-type compression chambers 4-5 are used to store filter media with different initial porosities, and the porosity decreases along the airflow direction. An isolation disc 4-6 is provided between the two bellows-type compressor airbags 4-5. The outer edge of the isolation disc 4-6 is fixed to the inner wall of the housing 4-1, thereby forming a radial limit. While suppressing the axial migration of the filter medium, it limits the position of one end of the bellows-type compressor airbag 4-5. This allows the volume of the bellows-type compressor airbag 4-5 to be changed when the positions of the upper partition 4-3 and the lower partition 4-4 are adjusted by the axial compression mechanism 5, thereby adjusting the porosity of the filter medium in the bellows-type compressor airbag 4-5. A displacement sensor 4-7 is provided on the isolation disc 4-6 to detect the distance between the isolation disc 4-6 and the upper partition 4-3 and the lower partition 4-4, respectively.

[0037] In some embodiments, multiple conventional airbags are also stacked between the two accordion-type compressed airbags 4-5. The multiple conventional airbags are separated from each other, as well as from the conventional airbags and the accordion-type compressed airbags 4-5, by an isolation plate 4-6; since only one side of the two accordion-type compressed airbags 4-5 is connected to the upper partition 4-3 and the lower partition 4-4, the volume of the remaining conventional airbags is fixed except for the two accordion-type compressed airbags 4-5.

[0038] In some embodiments, a plurality of accordion-type compressed air bags 4-5 are axially stacked between the upper and lower partitions; the isolation disc 4-6 between adjacent accordion-type compressed air bags 4-5 is slidably connected to the inner wall of the housing 4-1, thereby allowing the volume of all accordion-type compressed air bags 4-5 to be adjusted simultaneously by adjusting the positions of the upper partition 4-3 and the lower partition 4-4.

[0039] like Figure 6 As shown, the axial compression mechanism 5 includes a fixed base 5-1, a cylinder 5-2, a piston rod 5-3, and a second servo motor 5-4 mounted on the fixed base. The cylinder 5-2 has a hollow structure, forming a sealed chamber inside to accommodate the piston and guide its linear motion. One end of the piston rod 5-3 is rigidly connected to the piston, and the other end extends out of the cylinder as a thrust output end, connecting to the upper partition 4-3 or the lower partition 4-4 through a through hole in the housing 4-1. The second servo motor 5-4 drives the piston rod 5-3 to move linearly, thereby adjusting the positions of the upper partition 4-3 and the lower partition 4-4.

[0040] The control unit coordinates the operation of each component, adjusts based on particle state, and combines precise detection and assisted reset to achieve dynamic adjustment of the pore structure of the filter medium. It also links with the spacing adjustment component through a displacement sensor to complete the closed-loop coordination of pretreatment and filtration adjustment.

[0041] Example 2

[0042] like Figure 7 As shown, a gas filtration method with self-adjusting porosity is described, employing the gas filtration device described in Example 1. This gas filtration method includes the following steps:

[0043] Step 1: Determine the filter medium and the preset distance between the porous conductive component 2-3 and the needle-shaped conductive component 2-4 based on the gas to be filtered. In this embodiment, ammonia is used as the gas to be filtered, and open-cell polyurethane elastic foam and expanded polytetrafluoroethylene (ePTFE) elastic porous membrane are used as the filter medium. The open-cell polyurethane elastic foam and the expanded polytetrafluoroethylene elastic porous membrane are sequentially stored in different bellows-type compression bladders 4-5 along the airflow direction. The former has an initial porosity of 85%, and the latter has an initial porosity of 70%. The structural parameters of the gas pretreatment device 2 are adjusted according to the preset distance using the spacing adjustment component 3.

[0044] Step 2: The gas to be filtered is introduced into the gas pretreatment device 2 through the air inlet of the sealed chamber. The porous conductive component 2-3 and the needle-shaped conductive component 2-4 in the gas pretreatment device 2 electrolyze the gas to be filtered, causing the particle state of the gas to change as it passes through.

[0045] Step 3: Input the pretreated gas into the adjustable filter assembly 4. The adjustable filter assembly 4 performs graded filtration on the pretreated gas. Large particles are intercepted by the open-cell polyurethane elastic foam section, and small particles are finely filtered by the expanded polytetrafluoroethylene porous membrane section.

[0046] Step 4: Detect the particle concentration and particle size of the pretreated gas using particle sensors 2-6. Obtain the target compression stroke based on the particle concentration and particle size. (Target compression stroke including open-cell polyurethane elastic foam) The target compression stroke of expanded polytetrafluoroethylene elastic porous membrane Its expression is:

[0047]

[0048] in, Porosity – compressibility coefficient (a core material property); The initial porosity of the filter medium; Minimum allowable porosity for the filter medium (to prevent crushing); This is the concentration influence coefficient; Particle concentration (mg / m³) 3 ); This is the particle size influence coefficient; The particle size is denoted as μm.

[0049] If the target is to compress the stroke Greater than the maximum allowable compression stroke threshold Then, based on the target, the journey is compressed. Obtain the target spacing of conductive components Its expression is:

[0050]

[0051] in, This is the initial spacing; The main gain is adjusted for spacing (experimental calibration coefficient); and The target compression strokes for the two filter media are respectively; The system's rated target stroke; This is the piecewise gradient difference correction coefficient (experimental calibration coefficient).

[0052] With target spacing The spacing of the conductive components is adjusted by the control adjustment amount of the spacing adjustment component 3. The larger the average compression stroke of the two segments and the more significant the stroke difference, the smaller the spacing of the conductive components, so as to enhance the particle agglomeration effect, reduce the filtration load, and realize closed-loop coordinated adjustment of filtration status and pretreatment parameters.

[0053] Repeat the above process until the target compression stroke is achieved. Less than the maximum allowable compression stroke threshold Compress the journey to the target. The axial compression mechanism 5 applies a corresponding axial force to the adjustable filter assembly 4, independently adjusting the porosity of the two filter media: the polyurethane elastic foam and the expanded polytetrafluoroethylene porous membrane.

[0054] Step 5: Detect the particle size of the gas processed by the adjustable filter assembly 4 using the particle state detection unit. Based on this particle size, determine the target spacing of the conductive components. and with target spacing The spacing of the conductive components is adjusted by the control adjustment amount of the spacing adjustment component 3. Target spacing The expression is:

[0055]

[0056] in, The spacing of the conductive components before adjustment; This is the stroke deviation correction coefficient control, which indicates the adjustment strength of the deviation. It has no effect when the deviation is 0. This refers to the actual compression stroke of the filter medium; Compress the travel distance to achieve the preset target; The outlet particle size feedback coefficient; The particle size of the gas after treatment by the adjustable filter component 4.

[0057] Step 6: Repeat steps 4 and 5 until the particle size of the gas processed by the adjustable filter component 4 meets the expectations, thus achieving the filtration of ammonia.

Claims

1. A gas filtration device with self-adjusting porosity, comprising an outer frame (1) and a gas pretreatment device (2) and an adjustable filter assembly (4) installed inside the outer frame (1); the gas pretreatment device (2) is used to pretreat the gas to be filtered by electrolysis; the adjustable filter assembly (4) is used to further filter the pretreated gas using a filter medium; characterized in that: The adjustable filter assembly (4) includes a housing (4-1) and a compression chamber (4-2) installed inside the housing (4-1); the compression chamber (4-2) includes an upper partition (4-3), a lower partition (4-4), and multiple accordion-type compression bladders (4-5) between the upper and lower partitions for storing different filter media; the accordion-type compression bladders (4-5) are axially stacked along the gas flow direction, and the porosity of the filter media stored in the accordion-type compression bladders (4-5) decreases along the gas flow direction; adjacent accordion-type compression bladders (4-5) are isolated by an isolation disc (4-6); The gas filtration device also includes an axial compression mechanism (5); the axial compression mechanism (5) is used to adjust the position of the upper partition (4-3) and the lower partition (4-4) to control the porosity of the filter medium in the bellows-type compression airbag (4-5).

2. A self-adjusting porosity gas filter device according to claim 1, wherein: The gas pretreatment device (2) electrolyzes the gas to be filtered through porous conductive components (2-3) and needle-shaped conductive components (2-4).

3. A self-adjusting porosity gas filter device according to claim 2, wherein: It also includes a control unit and a particle state detection unit; the particle state detection unit is used to detect the particle size of the gas particles after filtration by the adjustable filter assembly (4); the gas pretreatment device (2) also includes a particle sensor (2-6); the particle sensor (2-6) is used to monitor the particle size and particle concentration of the gas particles after pretreatment; the particle state detection unit is used to adjust the distance between the porous conductive component (2-3) and the needle-shaped conductive component (2-4) and the position of the upper partition (4-3) and the lower partition (4-4) according to the particle size and particle concentration of the gas particles after pretreatment and the particle size of the filtered gas particles.

4. A self-adjusting porosity gas filter device according to claim 2, wherein: It also includes a spacing adjustment component (3); the spacing adjustment component (3) drives the needle-shaped conductive component (2-4) to move horizontally under the action of a servo motor through a sliding pair consisting of a slider and a lead screw.

5. A gas filtration device with self-adjusting porosity according to claim 1, characterized in that: The outer edge of the isolation disc (4-6) is fixed to the inner wall of the housing (4-1); the axial compression mechanism (5) controls the moving distance of the upper partition (4-3) and the lower partition (4-4) respectively, so that the filter medium in the two outermost accordion-type compression airbags (4-5) reaches its corresponding set porosity.

6. The gas filtration device with self-adjusting porosity according to claim 1, characterized in that: The axial compression mechanism (5) includes a fixed base (5-1), a cylinder (5-2), a piston rod (5-3), and a second servo motor (5-4) mounted on the fixed base. The axial compression mechanism (5) drives the piston rod (5-3) to move linearly in the cylinder (5-2) through the second servo motor (5-4), thereby adjusting the positions of the upper partition (4-3) and the lower partition (4-4).

7. A gas filtration method with self-adjusting porosity, characterized in that: The gas filtration device with self-adjusting porosity as described in claim 1 is used; the gas filtration method includes: The filter medium and the preset distance between the porous conductive component (2-3) and the needle-shaped conductive component (2-4) are determined based on the gas to be filtered; the filter medium is stored in different bellows-type compressed air bags (4-5) according to the initial porosity of the filter medium; the gas to be filtered is passed into the gas pretreatment device (2) for pretreatment, and the pretreated gas is input into the adjustable filter assembly (4) for filtration.

8. A gas filtration method for self-adjusting porosity according to claim 7, characterized in that: During the gas filtration process, the particle size of the gas filtered by the adjustable filter assembly (4) is detected, and the distance between the porous conductive component (2-3) and the needle-shaped conductive component (2-4) is adjusted based on the particle size; the particle concentration and particle size of the pretreated gas after the distance adjustment are detected, and the porosity of the filter medium is adjusted based on the particle concentration and particle size; the above process is repeated until the particle size of the filtered gas meets the preset conditions.

9. A gas filtration method for self-adjusting porosity according to claim 8, characterized in that: The porosity adjustment method is as follows: the target compression stroke is obtained based on the particle concentration and particle size; if the target compression stroke is greater than the maximum allowable compression stroke threshold, the target spacing between the porous conductive component (2-3) and the needle-shaped conductive component (2-4) is obtained based on the target compression stroke. The gas pretreatment device (2) is adjusted by controlling the amount of the spacing adjustment component (3) with the target spacing; the above process is repeated until the target compression stroke is less than the maximum allowable compression stroke threshold; the corresponding axial force is applied to the upper partition (4-3) and the lower partition (4-4) with the target compression stroke to independently adjust the porosity of different filter media.

10. A gas filtration method for self-adjusting porosity according to claim 7, characterized in that: The gas to be filtered is ammonia; the filter medium is an open-cell polyurethane elastic foam and an expanded polytetrafluoroethylene elastic porous membrane.

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