Efficient air circulation purification device based on multi-stage composite filtering structure and operation method of efficient air circulation purification device

Abstract

The invention discloses an efficient air circulation purification device based on a multi-stage composite filtering structure and an operation method of the efficient air circulation purification device, and relates to the technical field of air purifiers. The air purifier comprises a main machine shell, a multi-stage filtering assembly, a fan set, an air duct structure, an air detection module and a control module. The fan set is composed of an axial flow fan and a centrifugal fan, the axial flow fan is installed on the main machine shell, the distance between the axial flow fan and the second-stage filter element where the centrifugal fan is located is 5-10 cm, and the air supply efficiency can be improved; the multi-stage filter assembly comprises a first-stage filter element, a second-stage filter element and a filter screen plate which can be detached and cleaned, so that graded filtration is realized. Through cooperation of the axial flow fan and the centrifugal fan, the axial flow fan drains air into the inner cavity of the purifier at a high speed, the centrifugal fan deeply purifies the air in the inner cavity, and the air is output through the air outlet; by combining a multi-stage filtering structure, the problems that an existing air purifier is insufficient in air volume, poor in flow state, low in purification efficiency and short in filter element service life are solved, and the air purifier has the advantages of efficient purification, intelligent adjustment and long service life.

Description

Technical Field

[0001] This invention relates to the field of air purifier technology, specifically to a high-efficiency air circulation and purification device based on a multi-stage composite filtration structure and its operation method. Background Technology

[0002] Air purifiers, as core devices for improving indoor air quality, are widely used in homes, offices, and other places. However, the design of existing home air purifiers often suffers from a disconnect between the actual needs of users and their usage scenarios, particularly in terms of airflow design and purification performance.

[0003] The design of the air duct and airflow directly determines the purification coverage and efficiency. Most models on the market suffer from the problem of "theoretical performance ≠ actual experience." This is mainly reflected in weak air intake force and poor airflow. Even with prolonged operation, the purification area remains limited to a 1-2 square meter area around the unit, resulting in extremely low efficiency. Even some air purifiers use dual centrifugal fans to attempt to increase airflow, but lacking proper duct and airflow design, the poor airflow ultimately only creates ineffective localized self-circulation around the unit. The air that needs purification cannot enter, and the purified air cannot be circulated far enough, failing to achieve effective whole-house air exchange.

[0004] Meanwhile, filter grade, filter lifespan, and purification speed are also key factors affecting the effectiveness of air purifiers. As the core filtration component, higher-grade HEPA filters offer better filtration, but also increase airflow resistance, further exacerbating poor airflow. Furthermore, current air purifiers lack airflow guidance and tiered filtration designs, making it difficult to create indoor air circulation, thus significantly limiting purification efficiency. If the core issues of airflow and airflow cannot be addressed, even the highest-grade and longest-lasting filters will struggle to achieve true purification.

[0005] Therefore, there is a need for an air purification device that can optimize duct design, enhance air volume and flow pattern, and achieve graded high-efficiency filtration to address the shortcomings of existing technologies. Summary of the Invention

[0006] Purpose of the invention: To address the problems of insufficient air volume, weak airflow, low purification efficiency, and short filter life in existing air purifiers, this invention provides a high-efficiency air circulation and purification device based on a multi-stage composite filtration structure. Through the coordinated operation of an axial flow fan and dual centrifugal fans, the innovative layout of the side air duct structure, and the multi-stage filtration structure, it achieves efficient air circulation and purification, extends the filter life, and improves the user experience.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A high-efficiency air circulation and purification device based on a multi-stage composite filtration structure includes a main unit housing, a multi-stage filtration assembly, a fan unit, an air duct structure disposed within the main unit housing, and an air detection module, a control module, a function display screen, and a push-button switch installed on the main unit housing. The fan unit includes an axial flow fan and a centrifugal fan. The axial flow fan is fixedly installed on the front and back of the main unit housing. The centrifugal fan is configured as a dual centrifugal fan and is symmetrically installed on the secondary filter element inside the main unit housing. The distance between the axial flow fan and the secondary filter element is 5-10cm. The air inlet of the axial flow fan faces the outside of the main unit housing, and the air outlet faces the inside of the main unit housing. The multi-stage filtration assembly includes a primary filter element, a secondary filter element, and a filter screen. The primary filter element is detachably installed at the air inlet of the axial flow fan without affecting the normal operation of the axial flow fan. The secondary filter element is located on the air inlet side of the centrifugal fan, and the filter screen is installed on the side wall of the duct structure, that is, on the inner side wall of the main unit housing corresponding to the duct. The air duct structure is a channel between the side of the dual centrifugal fan and the main unit housing. An arc-shaped guide plate is provided on the side of the air duct structure near the dual centrifugal fan to guide the air filter plate that is sent into the purification device by the axial flow fan but not drawn and purified by the dual centrifugal fan. The air detection module is used to detect air quality indicators. The control module is electrically connected to the air detection module, the fan unit, the function display screen and the key switch, and is used to control the operating status of the axial flow fan and the centrifugal fan and the working mode of the multi-stage filter components according to the air quality indicators or human operation commands.

[0008] As a further improvement to the above technical solution: The main housing includes a front housing, a rear housing, and a side housing. The front housing and the rear housing are each provided with mounting holes adapted to the axial flow fan. The edge of the mounting hole is provided with an annular mounting seat. The axial flow fan is fixed to the annular mounting seat by bolts. The outer side of the annular mounting seat is provided with threads. The primary filter element is provided with threads adapted to the annular mounting seat and is detachably connected to the annular mounting seat.

[0009] The primary filter element includes a frame and a primary filter cloth, which is made of ABS engineering plastic. The primary filter cloth is made of nylon with a mesh diameter of 50-100μm. The outer side of the frame is uniformly provided with anti-slip protrusions, and the inner ring of the frame is provided with threads that are compatible with the annular mounting seat.

[0010] The secondary filter element includes a HEPA filter layer and an activated carbon filter layer. The HEPA filter layer uses H13 or H14 grade HEPA filter material, and the activated carbon filter layer uses honeycomb activated carbon. The HEPA filter layer and the activated carbon filter layer are bonded and fixed together with hot melt adhesive, and are wrapped with a sealing frame. The sealing frame is sealed and fitted to the edge of the mounting groove of the secondary filter element.

[0011] The filter plate includes a filter frame and a filter layer. The filter frame is a rectangular structure with a support mesh on its inner side. The filter layer is sandwiched between the support mesh and the filter frame. The filter layer is made of PP meltblown filter material with a filtration accuracy of 10-20μm.

[0012] The air detection module includes a PM2.5 sensor, a PM10 sensor, and a formaldehyde sensor. Each sensor is installed in the air intake area of ​​the main unit housing and is connected to the control module via wires.

[0013] The control module includes a microcontroller and a drive circuit. The microcontroller uses an STM32 series chip. The drive circuit is electrically connected to the axial flow fan and the centrifugal fan respectively, and is used to control the start and stop of the fans and adjust their speed. The control module is also electrically connected to an ultraviolet sterilization module, an antibacterial and antiviral module, a negative ion generator, and a mobile APP communication module. The ultraviolet sterilization module is installed on the air outlet side of the secondary filter element. The antibacterial and antiviral module is set on the surface of the secondary filter element. The negative ion generator is installed at the air outlet of the main unit housing.

[0014] The air outlet of the main unit housing is provided with an air guiding mechanism, which includes an air guiding plate and a drive motor. The air guiding plate is rotatably connected to the main unit housing via a rotating shaft, and the drive motor is connected to the rotating shaft to drive the air guiding plate to rotate and adjust the air outlet direction.

[0015] A method for operating a high-efficiency air circulation and purification device based on a multi-stage composite filtration structure, applicable to the high-efficiency air circulation and purification device based on a multi-stage composite filtration structure as described in any one of claims 1-8, includes the following steps: 1. Initialization and Data Acquisition Phase S101: Device power-on initialization: Start the control module, air detection module, function display screen, and mobile APP communication module to complete the device self-test (if the self-test fails, the display screen / APP will display "Device Fault" and the process will terminate). S102: Air Quality Data Acquisition: The air detection module collects three core indoor indicators in real time: - PM10 concentration (unit: μg / m³) - PM2.5 concentration (unit: μg / m³) - formaldehyde concentration (unit: mg / m³). The data is updated every 5 seconds and synchronously transmitted to the control module and mobile APP. S103: Manual command detection: The control module synchronously detects the "mode switch key" signal (user manual operation) and the "mode selection" command from the mobile APP, and prioritizes responding to manual commands (if a manual command exists, jump to S203; if no manual command exists, enter automatic judgment). 2. Mode Judgment and Switching Phase Automatic mode judgment S201: Light pollution judgment: When the conditions of "PM10 > 50 μg / m³ and PM2.5 ≤ 35 μg / m³ and formaldehyde ≤ 0.08 mg / m³" are met, the system will automatically switch to "rapid coarse filtration mode" and jump to S301. S202: Moderate / Severe Pollution Judgment: When PM2.5 > 35 μg / m³ or formaldehyde > 0.08 mg / m³ (regardless of PM10 value), it automatically switches to "Deep Purification Mode" and jumps to S401; S203: Manual mode selection: Users can select via the "mode switch button" or the APP: - Select "Quick coarse filtration mode" → jump to S301 - Select "deep purification mode" → jump to S401; 3. Mode Operation Control Phase 3.1 Operation in rapid coarse filtration mode (suitable for light contamination) S301: Fan Control: Control module output commands: - Axial flow fan start (medium speed) - Dual centrifugal fans shut down; S302: Airflow path control: outside air → primary filter (primary coarse filtration: removes large dust / hair particles) → axial flow fan → side air duct → part of the airflow passes through the air duct → filter plate (auxiliary filtration: removes medium particulate impurities) → all airflow is discharged from the left / right air outlet of the main unit; S303: Operational status feedback: The function display screen / APP shows "Fast coarse filtration mode", and simultaneously displays the real-time PM10 concentration and purification coverage range (15-20㎡), updating once every 30 seconds; S304: Mode switching detection: Continuously detect S102 (air quality data) and S103 (manual command): - If the data meets S202 (moderate / heavy pollution) or manually select "deep purification" → jump to S401 - If the data returns to "PM10≤50μg / m³" → jump to S501 (standby); 3.2 Deep purification mode operation (suitable for moderate / heavy pollution) S401: Fan Control: Control module output commands: - Axial fan start (high speed) - Dual centrifugal fan start (high speed), real-time monitoring of load current (stable at 1.2-1.5A; if >2A, automatically reduce speed and prompt "fan overload"); S402: Airflow Path and Purification Control: Outside air → Primary filter (initial filtration) → Axial fan → Side duct → Most airflow → Duct outlet → Centrifugal fan inlet → Small portion of airflow → Duct → Filter plate (auxiliary filtration) → Centrifugal fan inlet → Centrifugal fan pressurization (300Pa) → Secondary filter (HEPA filter intercepts PM2.5 / PM1 + activated carbon adsorbs formaldehyde / TVOC) → Ultraviolet sterilization module (sterilization rate ≥99%) → Negative ion generator (releases negative ions) → Air guide plate → Indoor areas; S403: Operational status feedback: The function display screen / APP shows "Deep Purification Mode", and synchronously displays real-time PM2.5, formaldehyde concentration, CADR value (200-220m³ / h), and purification coverage area (30-40㎡), updating once every 30 seconds; S404: Mode switching detection: Continuously monitor S102 (air quality data) and S103 (manual command): - If the data meets S201 (light pollution) and there is no manual command → jump to S301 - If the data recovers to "PM2.5≤35μg / m³ and formaldehyde≤0.08mg / m³" → jump to S501 (standby) - If "rapid coarse filtration" is manually selected → jump to S301; 4. Standby and Termination Phases S501: Enter standby mode: When the air quality returns to the standard (PM10≤50μg / m³, PM2.5≤35μg / m³, formaldehyde≤0.08mg / m³) and there is no manual command, the control module shuts down the axial flow fan, dual centrifugal fans, and ultraviolet sterilization module, leaving only the air detection module (collecting data once every 30 seconds) and the display screen (displaying "standby"). S502: Process Termination: When the user presses and holds the "Power Off" button or the APP sends a "Power Off" command, the device loses power, all modules stop running, and the process terminates.

[0016] As a further improvement to the above technical solution: It also includes a filter life management phase, which includes the following steps: S601: Filter life calculation: The control module accumulates the purification volume (CCM value) in real time and calculates the remaining life of three types of filter elements according to the preset algorithm (CCM value / rated total purification volume): - Primary filter element (washable, no life value, only indicates the cleaning cycle) - Filter screen (rated life corresponds to CCM value, reminder is triggered when the remaining life < 10%) - Secondary filter element (rated life corresponds to CCM value, reminder is triggered when the remaining life < 10%). S602: Maintenance reminder trigger: - Primary filter element: Every 7 days (168 hours), the display screen / APP will prompt "Recommended cleaning" - Filter screen / secondary filter element: When the remaining life is <10%, the display screen will light up red and the APP will push a notification prompting "Filter element needs to be replaced"; S603: Reset after maintenance: After the user completes the primary filter cleaning or filter replacement, the control module will reset the corresponding filter's cumulative CCM value and recalculate the lifespan by clicking the "Reset" button or "Reset Lifespan" in the APP.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. Add an axial fan in front of the centrifugal fan, with the distance between the two controlled at 5-10cm. The large air volume of the axial fan and the high pressure of the centrifugal fan create an air volume superposition, improving the air intake efficiency and air delivery distance. The actual test shows that the purification coverage area can reach 30-40㎡, far exceeding the local purification effect of 1-2㎡ of existing air purifiers.

[0018] 2. It adopts a three-stage filtration structure of "first-stage filter element - filter screen plate - second-stage filter element" to specifically remove impurities and harmful gases of different particle sizes, improving purification efficiency by more than 40%; and the first-stage filter element can be disassembled and cleaned to reduce usage costs, while the filter screen plate and second-stage filter element are easy to replace, improving user experience.

[0019] 3. The side of the dual centrifugal fan has an air duct. Combined with the design of the arc-shaped guide plate, when the axial flow fan sends air into the purification device but is not drawn in and purified by the dual centrifugal fan, the air is guided to the filter plate, which avoids the dual centrifugal fan being overloaded and extends the service life of the fan. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the internal structure of the present invention; Figure 2 This is a perspective view of the present invention; Figure 3 This is a top cross-sectional view of the present invention; Figure 4 This is a side cross-sectional view of the present invention; Figure 5 This is a flowchart of the working algorithm of the present invention.

[0021] In the diagram: 1. Main unit housing; 101. Front housing; 102. Rear housing; 103. Side housing; 2. Axial flow fan; 3. Dual centrifugal fans; 4. Primary filter element; 401. Frame; 402. Primary filter cloth; 5. Secondary filter element; 6. Filter screen; 601. Filter screen frame; 602. Filter layer; 603. Support mesh; 7. Arc-shaped guide plate; 8. Annular mounting base; 9. Air guiding mechanism; 10. Function display screen; 11. Negative ion generator. Detailed Implementation

[0022] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0023] Applicant's design Figure 1-4 The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure shown includes a main unit housing 1, a multi-stage filtration assembly, a fan unit, an arc-shaped guide plate 7, an air detection module, a control module, a function display screen 10, and push-button switches.

[0024] The main housing 1 is integrally injection molded from high-strength ABS engineering plastic, including a front housing 101, a rear housing 102, a left housing 103, and a right housing 103. Each housing is connected by snap-fit ​​installation and then bolted together. EPDM sealing strips are provided at the joints to ensure both sealing and sound insulation. The front housing 101 and rear housing 102 have circular mounting holes corresponding to the axial flow fan 2. An annular mounting seat 8 is integrally formed on the edge of each mounting hole, with threads on the outer side for rotating and fixing with the primary filter element 4. Circular filter screen mounting grooves are provided on the inner walls of the two side housings 103 for installing and fixing the filter screen plates 6. Strip-shaped guide plates are provided on the outer sides of the two side housings 103 corresponding to the filter screen plates 6 to ensure efficient exhaust of filtered air.

[0025] The fan unit includes an axial flow fan 2 and two centrifugal fans 3, with a spacing of 5-10cm between them, working together to achieve airflow aggregation and distribution. Two axial flow fans 2 are installed, mounted on the annular mounting bases 8 of the front casing 101 and the rear casing 102 respectively, and secured with M4 hexagonal socket bolts. The axial flow fan 2 is a FA-4020 low-pressure, high-volume type, with a rated airflow ≥120m³ / h and a pressure ≥50Pa. The air inlet faces outwards from the casing, and the air outlet faces inwards from the centrifugal fans 3, ensuring efficient intake and delivery of external air to the core purification area. The centrifugal fans 3 are MF-150P high-pressure types, with a rated pressure ≥300Pa and a rated airflow ≥80m³ / h. The centrifugal fans 3 are symmetrically installed at the center inside the main casing 1.

[0026] (a) Main test equipment One high-efficiency air circulation and purification device based on a multi-stage composite filtration structure as described in this invention is used, wherein: 1. Axial flow fan: Model FA-4020 low-pressure high-volume type, rated air volume ≥120m³ / h, air pressure ≥50Pa, the distance between the fan and the secondary filter element (centrifugal fan reference position) can be changed by adjusting the installation position. 2. Centrifugal fan: Model MF-150P high-pressure type, rated air pressure ≥300Pa, rated air volume ≥80m³ / h, symmetrically installed in the main unit casing, with fixed position. 3. Secondary filter element: It consists of an H13 grade HEPA filter layer and a honeycomb coconut shell activated carbon filter layer, which is fixed in position relative to the centrifugal fan and serves as a reference point for distance measurement.

[0027] (ii) Auxiliary measuring equipment 1. Air volume tester: Model TSI-8380, measurement range 0-1000m³ / h, accuracy ±2%, used to measure the air intake volume of the device at different distances, thereby characterizing the air intake efficiency. 2. Laser rangefinder: Model Bosch GLM500, measuring range 0.05-50m, accuracy ±1mm, used to measure the air delivery distance, that is, the farthest distance that the purified air can stably reach (with a wind speed ≥0.3m / s as the standard for stable arrival). 3. Anemometer: Model Testo-410-2, measuring range 0-20m / s, accuracy ±0.01m / s, used in conjunction with a laser rangefinder to determine the air delivery distance. 4. Adjustable mounting bracket: used to fix the axial flow fan and precisely adjust the distance between it and the secondary filter element (centrifugal fan reference position), with an adjustment accuracy of 1cm.

[0028] (III) Test Environment Parameters 1. Test space: A closed room with a volume of 10m×8m×3m (length×width×height) was selected. The initial indoor air quality was stable, with PM2.5 concentration ≤35μg / m³, formaldehyde concentration ≤0.08mg / m³, and no obvious air flow interference. 2. Ambient temperature: Maintain at 25±2℃, relative humidity at 50±5%, to avoid the impact of temperature and humidity changes on fan performance and airflow.

[0029] (I) Experimental Preparation 1. Place the air purification device in the center of the test room, ensuring that there are no obstructions around the device and that it is at least 2 meters away from walls and other objects to avoid airflow obstruction.

[0030] 2. Check whether the axial flow fan, centrifugal fan, air volume tester, laser rangefinder, anemometer and other equipment are working properly, calibrate each measuring instrument and ensure data accuracy.

[0031] 3. Using the adjustable mounting bracket, adjust the initial position of the axial flow fan to a distance of 2cm from the secondary filter element, and record the initial distance value.

[0032] (II) Performance testing at different distances 1. Air intake efficiency test: Start the device and switch it to deep purification mode, so that the axial flow fan runs at high speed (rated speed) and the centrifugal fan runs at high speed. Wait for the equipment to stabilize (after running for 10 minutes).

[0033] Install the air inlet probe of the air volume tester at the air inlet end of the axial flow fan, close to the outside of the first-stage filter element, and continuously measure for 3 minutes. Record the air volume per minute and take the average value as the air volume at that distance (air inlet efficiency characterization value). 2. Air delivery distance test: Directly in front of the air outlet of the device, starting from the air outlet, use a laser rangefinder to mark a measurement point every 1m, until the end of the room. Measure the wind speed at each marked point using an anemometer, taking three measurements at each point and averaging the results. If the wind speed at a measurement point is ≥0.3 m / s, continue measuring further away; if the wind speed at a certain marked point is <0.3 m / s, stop measuring and take the distance from the previous marked point as the air supply distance at that distance. 3. Distance adjustment and repeated testing: Using the adjustable mounting bracket, the distance between the axial fan and the secondary filter element was adjusted sequentially to 3cm, 4cm, 5cm, 6cm, 8cm, 10cm, 11cm, 12cm, 13cm, and 15cm. After each distance adjustment, the test process of steps 1 and 2 was repeated, and the air intake and air delivery distance data at each distance were recorded. Each distance was tested 3 times, and the average value was taken as the final result.

[0034] (a) Recording of test data The test results of air intake volume (air intake efficiency) and air delivery distance at different distances are summarized in the following table:

[0035] (II) Results Analysis 1. Air intake efficiency analysis: As the distance between the axial fan and the secondary filter cartridge gradually increases from 2cm to 8cm, the air intake volume shows a continuous upward trend. At a distance of 2cm, the air intake volume is only 85m³ / h. As the distance increases, the flow resistance between the axial fan and the centrifugal fan gradually decreases, the airflow becomes smoother, and the air intake volume gradually increases, reaching a maximum of 120m³ / h at a distance of 8cm. At this point, the air intake efficiency is the highest, reaching the rated air volume level of the axial fan. When the distance exceeds 8cm, the air intake volume begins to gradually decrease. At a distance of 10cm, the air intake volume is 115m³ / h, which is slightly lower than the maximum value but still remains at a high level. When the distance increases to 15cm, the air intake volume drops to 78m³ / h, far below the optimal value. This is because when the distance is too large, the airflow delivered by the axial fan will experience diffusion loss before reaching the centrifugal fan (secondary filter element), and some airflow cannot be effectively drawn in by the centrifugal fan, resulting in reduced air intake efficiency. 2. Air supply distance analysis: The trend of air delivery distance variation is basically consistent with that of air intake volume. At a distance of 2cm, the air delivery distance is only 6.2m; as the distance increases, the air delivery distance gradually extends, reaching a maximum of 11.8m at a distance of 8cm. This is because the improved air intake efficiency provides sufficient air volume for subsequent airflow delivery, and the centrifugal fan can more effectively pressurize and deliver the air, thereby extending the air delivery distance. When the distance exceeds 8cm, the air delivery distance begins to shorten. At a distance of 10cm, the air delivery distance is 11.2m, which is still at a relatively high level; at a distance of 15cm, the air delivery distance drops to 6.0m, similar to the initial distance of 2cm. This is because the intake air volume decreases, and the centrifugal fan cannot pressurize and deliver enough air, resulting in a decrease in air delivery capacity and an inability to deliver the purified air to a distant area. 3. Determining the optimal distance range: Considering the two key indicators of air intake efficiency and air delivery distance, when the distance between the axial flow fan and the secondary filter element (the reference position of the centrifugal fan) is 5-10cm, the air intake volume of the device is maintained above 112m³ / h and the air delivery distance is above 10.5m. Both performance indicators are at a relatively good level. The optimal performance was observed at a distance of 8cm, achieving an air intake volume of 120m³ / h and a delivery distance of 11.8m. While performance was slightly lower at distances of 5cm and 10cm compared to 8cm, it still offered significant advantages over other distances and met the requirements for high-efficiency purification and wide-area coverage. However, at distances less than 5cm or greater than 10cm, both air intake efficiency and delivery distance decreased significantly, failing to meet the optimal performance standards designed for the device. Therefore, the optimal distance range between the axial flow fan and the centrifugal fan (secondary filter element) was determined to be 5-10cm.

[0036] The arc-shaped baffle 7 is used to guide redundant air that is not drawn in by the dual centrifugal fans 3, achieving airflow diversion and load protection. The baffle is made of ABS engineering plastic, with a 1 / 4 circular arc structure in cross-section, an arc radius of 8-10cm, and a thickness of 3mm. The surface is polished and then coated with polytetrafluoroethylene, with a surface roughness ≤Ra0.8μm to reduce airflow resistance. Two baffles are symmetrically arranged, and each baffle forms a sealed space with one of the two secondary filter elements 5 to prevent the gas filtered by the secondary filter element 5 from being contaminated, thus separating the purified air from the gas that has only undergone coarse filtration.

[0037] The multi-stage filtration system includes a primary filter element 4, a secondary filter element 5, and a filter screen 6, forming a three-stage process of "primary coarse filtration - deep purification - redundant filtration," balancing purification effectiveness with fan protection. The primary filter element 4 is detachably installed at the air inlet of the axial flow fan 2. The frame 401 is a circular structure made of ABS engineering plastic, with uniformly distributed anti-slip protrusions on the outer side, which is threaded to the annular mounting base 8 for easy installation and manual disassembly. The filter screen is made of nylon 66 material with a mesh diameter of 50-100μm, capable of filtering large particles of dust and animal hair, with a ventilation resistance ≤10Pa, without affecting the air intake efficiency of the axial flow fan 2. The filter screen is ultrasonically welded to the inside of the frame 401 to prevent it from falling off. The secondary filter element 5 is located on the air inlet side of the dual centrifugal fan 3, and fits tightly against the edge of the filter plate mounting groove. It consists of an H13 grade HEPA filter layer, a honeycomb coconut shell activated carbon filter layer, and a stainless steel support mesh 603 frame. Each of the three layers is 5mm thick, with a total thickness of 15mm. The HEPA filter layer has a filtration efficiency of ≥99.95% for 0.3-micron particles, intercepting fine particulate matter such as PM2.5 and PM1. The activated carbon filter layer has an iodine value of ≥1000mg / g, adsorbing harmful gases such as formaldehyde and TVOC. The support mesh 603 frame is located between the two filter layers to prevent filter deformation. The three layers are bonded together with hot melt adhesive (melting point 120℃), and the outside is wrapped with a rubber sealing frame to ensure no air leakage. The filter plate 6 is installed in the mounting groove on the inner wall of the side housing 103. The frame 401 is a rectangular structure made of ABS engineering plastic, with a stainless steel support mesh 603 on the inner side. The filter layer 602 is made of PP melt-blown filter material with a filtration accuracy of 10-20μm. It filters out medium-sized particulate impurities that are not intercepted by the primary filter element 4. It is fixed between the frame 401 and the support mesh 603 by snap-fit, making it easy to replace. The area of ​​the filter plate 6 is consistent with the coverage area of ​​the extended end of the arc-shaped guide plate 7, ensuring that all redundant airflow can be guided and filtered.

[0038] The air detection module is installed in the air intake area of ​​the front housing 101 and the rear housing 102 (5cm away from the air intake end of the axial fan 2). It includes PM2.5 and PM10 sensors (model SDS011) and formaldehyde sensor (model ZE08-CHO). Each sensor is connected to the control module through DuPont wires. The detection data is updated once per second, and the air quality is fed back in real time. The control module is installed in a sealed box inside the top of the housing. It includes an STM32F103 series microcontroller (72MHz main frequency, 64KB memory) and a drive circuit. The drive circuit includes an axial fan 2 drive unit (MOSFET IRF540) and a centrifugal fan drive unit (relay G5LE-14-DC12), which can control the start and stop of the fans and their speed (23 speeds for the axial fan and 2 speeds for the centrifugal fan). The control module is also electrically connected to the ultraviolet sterilization module (UV-C254nm, 3W power, installed on the air outlet side of the centrifugal fan), the silver ion antibacterial coating (coated on the surface of the secondary filter, antibacterial rate ≥99%), the negative ion generator 11 (model ZGF-001, installed at the air outlet of the housing) and the WiFi module (model ESP8266) to realize sterilization, negative ion purification and remote control. The function display screen 10 (TFT 1.8-inch touch screen) is installed on the front of the front housing 101, displaying air quality indicators, equipment status and filter life; the button switches are located below the display screen, including power button, mode switching button and fan speed adjustment button, to meet manual operation needs.

[0039] Initialization and data acquisition phase S101: Device power-on initialization: Start the control module, air detection module, function display screen, and mobile APP communication module to complete the device self-test (if the self-test fails, the display screen / APP will display "Device Failure" and the process will terminate).

[0040] S102: Air Quality Data Acquisition: The air detection module collects three core indoor indicators in real time: - PM10 concentration (unit: μg / m³) - PM2.5 concentration (unit: μg / m³) - formaldehyde concentration (unit: mg / m³). The data is updated every 5 seconds and synchronously transmitted to the control module and mobile APP.

[0041] S103: Manual command detection: The control module synchronously detects the "mode switch key" signal (user manual operation) and the "mode selection" command of the mobile APP, and prioritizes the response to manual commands (if a manual command exists, jump to S203; if no manual command exists, enter automatic judgment).

[0042] Mode determination and switching phase Automatic mode judgment S201: Light pollution judgment: When the conditions of "PM10 > 50 μg / m³ and PM2.5 ≤ 35 μg / m³ and formaldehyde ≤ 0.08 mg / m³" are met, the system will automatically switch to "rapid coarse filtration mode" and jump to S301.

[0043] S202: Moderate / Severe Pollution Judgment: When PM2.5 > 35 μg / m³ or formaldehyde > 0.08 mg / m³ (regardless of PM10 value), it automatically switches to "Deep Purification Mode" and jumps to S401.

[0044] S203: Manual mode selection: Users can select via the "mode switch button" or the APP: - Select "Quick coarse filtration mode" → jump to S301 - Select "deep purification mode" → jump to S401.

[0045] Mode operation control phase 3.1 Operation in rapid coarse filtration mode (suitable for light contamination) S301: Fan control: Control module output commands: - Axial flow fan start (medium speed) - Dual centrifugal fans shut down.

[0046] S302: Airflow path control: outside air → primary filter (primary coarse filtration: removes large dust / hair particles) → axial flow fan → side air duct → part of the airflow passes through the air duct → filter plate (auxiliary filtration: removes medium particulate impurities) → all airflow is discharged from the left / right air outlet of the main unit.

[0047] S303: Operation status feedback: The function display screen / APP displays "Fast coarse filtration mode", and simultaneously displays the real-time PM10 concentration and purification coverage range (15-20㎡), updating once every 30 seconds.

[0048] S304: Mode switching detection: Continuously detect S102 (air quality data) and S103 (manual command): - If the data meets S202 (moderate / heavy pollution) or manually select "deep purification" → jump to S401 - If the data returns to "PM10≤50μg / m³" → jump to S501 (standby).

[0049] 3.2 Deep purification mode operation (suitable for moderate / heavy pollution) S401: Fan control: Control module output commands: - Axial fan start (high speed) - Dual centrifugal fan start (high speed), real-time monitoring of load current (stable at 1.2-1.5A, if >2A, automatically reduce speed and prompt "fan overload").

[0050] S402: Airflow Path and Purification Control: Outside air → Primary filter (initial filtration) → Axial fan → Side duct → Most airflow → Duct outlet → Centrifugal fan inlet → Small portion of airflow → Duct → Filter plate (auxiliary filtration) → Centrifugal fan inlet → Centrifugal fan pressurization (300Pa) → Secondary filter (HEPA filter intercepts PM2.5 / PM1 + activated carbon adsorbs formaldehyde / TVOC) → Ultraviolet sterilization module (sterilization rate ≥99%) → Negative ion generator (releases negative ions) → Air guide plate → Indoor areas.

[0051] S403: Operational status feedback: The function display screen / APP displays "Deep Purification Mode", and synchronously displays real-time PM2.5, formaldehyde concentration, CADR value (200-220m³ / h), and purification coverage area (30-40㎡), updating once every 30 seconds.

[0052] S404: Mode switching detection: Continuously monitor S102 (air quality data) and S103 (manual command): - If the data meets S201 (light pollution) and there is no manual command → jump to S301 - If the data recovers to "PM2.5≤35μg / m³ and formaldehyde≤0.08mg / m³" → jump to S501 (standby) - If "rapid coarse filtration" is manually selected → jump to S301.

[0053] 4. Filter Cartridge Life Management Stage S601: Filter life calculation: The control module accumulates the purification volume (CCM value) in real time and calculates the remaining life of three types of filter elements according to the preset algorithm (CCM value / rated total purification volume): - Primary filter element (washable, no life value, only the cleaning cycle is indicated) - Filter screen (rated life corresponds to CCM value, reminder is triggered when the remaining life < 10%) - Secondary filter element (rated life corresponds to CCM value, reminder is triggered when the remaining life < 10%).

[0054] S602: Maintenance reminder trigger: - Primary filter element: Every 7 days (168 hours), the display screen / APP will prompt "Recommended cleaning" - Filter screen / secondary filter element: When the remaining life is <10%, the display screen will light up red and the APP will push a notification prompting "Filter element needs to be replaced".

[0055] S603: Reset after maintenance: After the user completes the primary filter cleaning or filter replacement, the control module will reset the corresponding filter's cumulative CCM value and recalculate the lifespan by clicking the "Reset" button or "Reset Lifespan" in the APP.

[0056] 5. Standby and Termination Phase S501: Enter standby mode: When the air quality returns to the standard (PM10≤50μg / m³, PM2.5≤35μg / m³, formaldehyde≤0.08mg / m³) and there is no manual command, the control module shuts down the axial flow fan, dual centrifugal fan, and ultraviolet sterilization module, and only keeps the air detection module (collecting data once every 30 seconds) and the display screen (displaying "standby").

[0057] S502: Process Termination: When the user presses and holds the "Power Off" button or the APP sends a "Power Off" command, the device loses power, all modules stop running, and the process terminates.

[0058] The operating mode of this device can be intelligently switched by the control module based on the air quality indicators detected by the air detection module. It can also be manually selected via a button switch or a mobile APP. The specific working process is as follows: Rapid coarse filtration mode (suitable for light pollution, such as PM10 exceeding the standard only): When the air detection module detects an indoor PM10 concentration > 50 μg / m³, and a PM2.5 concentration ≤ 35 μg / m³ and a formaldehyde concentration ≤ 0.08 mg / m³, the control module automatically switches to rapid coarse filtration mode; users can also manually select this mode via the mode switch button. At this time, the control module starts the axial flow fan (medium speed) and shuts off the dual centrifugal fans. External air undergoes initial coarse filtration through the primary filter at the axial flow fan inlet, removing large particles of dust, animal hair, and other impurities. The air is then sent into the side duct structure by the axial flow fan. During airflow within the duct, some air is further filtered by the filter screen on the inner wall of the duct (removing medium-sized particles), and finally, all air is discharged from the outlets on the left and right sides of the main unit casing, achieving rapid coarse filtration and air circulation, with a purification coverage area of ​​15-20 square meters.

[0059] Deep purification mode (suitable for moderate / heavy pollution, such as PM2.5 and formaldehyde exceeding the standard): When the air detection module detects an indoor PM2.5 concentration > 35 μg / m³ or a formaldehyde concentration > 0.08 mg / m³, the control module automatically switches to deep purification mode; users can also manually select this mode via the mode switch button. At this time, the control module simultaneously starts the axial flow fan (high speed) and the dual centrifugal fans (high speed). After initial filtration by the primary filter, external air is delivered to the side duct structure by the axial flow fan; due to the high-pressure suction of the dual centrifugal fans, most of the airflow directly enters the centrifugal fan inlet through the duct outlet, while a small portion enters the centrifugal fan after auxiliary filtration through the filter screen on the inner wall of the duct, preventing excessive airflow from overloading the centrifugal fan (actually measured centrifugal fan load current is stable at 1.2-1.5A, lower than the rated current of 2A); after the airflow is pressurized by the centrifugal fan (air pressure increased to 300Pa), it is forcibly forced through… The air undergoes deep purification through a two-stage filtration system consisting of a HEPA filter layer (intercepting PM2.5 and PM1) and an activated carbon filter layer (adsorbing formaldehyde and TVOC). The purified air is then sterilized by an ultraviolet sterilization module (sterilization rate ≥99%) and treated by a negative ion generator (releasing negative ions to improve air quality). Finally, the air is guided to various areas of the room by the air outlet's guide plate, achieving efficient purification throughout the house. The purification speed (CADR value) can reach 200-220 m³ / h, and the purification coverage area can reach 30-40 square meters.

[0060] In addition, the primary filter can be disassembled and cleaned once a week. After rinsing with water to remove impurities, it can be reused after drying. The filter screen is recommended to be replaced every 3 months, and the secondary filter is recommended to be replaced every 6-8 months. The control module will automatically calculate the filter life based on the cumulative purification volume (CCM value) and remind you to replace it on the function display screen and mobile APP, reducing the cost of use.

[0061] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A high-efficiency air circulation and purification device based on a multi-stage composite filtration structure, comprising a main unit housing, characterized in that: It also includes a multi-stage filtration system, a fan unit, and an air duct structure housed within the main unit housing, as well as an air detection module, a control module, a function display screen, and push-button switches mounted on the main unit housing; The fan unit includes an axial flow fan and a centrifugal fan. The axial flow fan is fixedly installed on the front and back of the main unit housing. The centrifugal fan is configured as a dual centrifugal fan and is symmetrically installed inside the main unit housing. The distance between the axial flow fan and the secondary filter element is 5-10cm. The air inlet of the axial flow fan faces the outside of the main unit housing, and the air outlet faces the inside of the main unit housing. The multi-stage filtration assembly includes a primary filter element, a secondary filter element, and a filter screen. The primary filter element is detachably installed at the air inlet of the axial flow fan without affecting the normal operation of the axial flow fan. The secondary filter element is located on the air inlet side of the centrifugal fan, and the filter screen is installed on the side wall of the duct structure, that is, on the inner side wall of the main unit housing corresponding to the duct. The air duct structure is a channel between the side of the dual centrifugal fan and the main unit housing. An arc-shaped guide plate is provided on the side of the air duct structure near the dual centrifugal fan to guide the air filter plate that is sent into the purification device by the axial flow fan but not drawn and purified by the dual centrifugal fan. The air detection module is used to detect air quality indicators. The control module is electrically connected to the air detection module, the fan unit, the function display screen and the key switch, and is used to control the operating status of the axial flow fan and the centrifugal fan and the working mode of the multi-stage filter components according to the air quality indicators or human operation commands.

2. The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure according to claim 1, characterized in that: The main housing includes a front housing, a rear housing, and a side housing. The front housing and the rear housing are each provided with mounting holes adapted to the axial flow fan. The edge of the mounting hole is provided with an annular mounting seat. The axial flow fan is fixed to the annular mounting seat by bolts. The outer side of the annular mounting seat is provided with threads. The primary filter element is provided with threads adapted to the annular mounting seat and is detachably connected to the annular mounting seat.

3. The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure according to claim 2, characterized in that: The primary filter element includes a frame and a primary filter cloth, which is made of ABS engineering plastic. The primary filter cloth is made of nylon with a mesh diameter of 50-100μm. The outer side of the frame is uniformly provided with anti-slip protrusions, and the inner ring of the frame is provided with threads that are compatible with the annular mounting seat.

4. The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure according to claim 1, characterized in that: The secondary filter element includes a HEPA filter layer and an activated carbon filter layer. The HEPA filter layer uses H13 or H14 grade HEPA filter material, and the activated carbon filter layer uses honeycomb activated carbon. The HEPA filter layer and the activated carbon filter layer are bonded and fixed together with hot melt adhesive, and are wrapped with a sealing frame. The sealing frame is sealed and fitted to the edge of the mounting groove of the secondary filter element.

5. The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure according to claim 1, characterized in that: The filter plate includes a filter frame and a filter layer. The filter frame is a rectangular structure with a support mesh on its inner side. The filter layer is sandwiched between the support mesh and the filter frame. The filter layer is made of PP meltblown filter material with a filtration accuracy of 10-20μm.

6. The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure according to claim 1, characterized in that: The air detection module includes a PM2.5 sensor, a PM10 sensor, and a formaldehyde sensor. Each sensor is installed in the air intake area of ​​the main unit housing and is connected to the control module via wires.

7. The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure according to claim 1, characterized in that: The control module includes a microcontroller and a drive circuit. The microcontroller uses an STM32 series chip. The drive circuit is electrically connected to the axial flow fan and the centrifugal fan respectively, and is used to control the start and stop of the fans and adjust their speed. The control module is also electrically connected to an ultraviolet sterilization module, an antibacterial and antiviral module, a negative ion generator, and a mobile APP communication module. The ultraviolet sterilization module is installed on the air outlet side of the secondary filter element. The antibacterial and antiviral module is set on the surface of the secondary filter element. The negative ion generator is installed at the air outlet of the main unit housing.

8. The high-efficiency air circulation and purification device based on a multi-stage composite filtration structure according to claim 1, characterized in that: The air outlet of the main unit housing is provided with an air guiding mechanism, which includes an air guiding plate and a drive motor. The air guiding plate is rotatably connected to the main unit housing via a rotating shaft, and the drive motor is connected to the rotating shaft to drive the air guiding plate to rotate and adjust the air outlet direction.

9. A method for operating a high-efficiency air circulation and purification device based on a multi-stage composite filtration structure, applicable to the high-efficiency air circulation and purification device based on a multi-stage composite filtration structure as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Initialization and data acquisition stage S101: Device power-on initialization: Start the control module, air detection module, function display screen, and mobile APP communication module to complete the device self-test. If the self-test fails, the display screen / APP will display "Device failure" and the process will terminate. S102: Air Quality Data Acquisition: The air detection module collects three core indoor indicators in real time: - PM10 concentration (unit: μg / m³) - PM2.5 concentration (unit: μg / m³) - formaldehyde concentration (unit: mg / m³). The data is updated every 5 seconds and synchronously transmitted to the control module and mobile APP. S103: Manual command detection: The control module synchronously detects the "mode switch key" signal and the "mode selection" command from the mobile APP, and prioritizes responding to manual commands. If a manual command exists, it jumps to S203; if no manual command exists, it enters automatic judgment. (2) Mode judgment and switching stage Automatic mode judgment S201: Light pollution judgment: When the conditions of "PM10 > 50 μg / m³ and PM2.5 ≤ 35 μg / m³ and formaldehyde ≤ 0.08 mg / m³" are met, the system will automatically switch to "rapid coarse filtration mode" and jump to S301. S202: Moderate / Severe Pollution Judgment: When "PM2.5 > 35 μg / m³ or formaldehyde > 0.08 mg / m³" is met, it will automatically switch to "Deep Purification Mode" and jump to S401; S203: Manual mode selection: Users can select via the "mode switch button" or the APP: - Select "Quick Coarse Filtration Mode" → jump to S301 - Select "Deep Purification Mode" → jump to S401; (3) Mode operation control stage (3.1) Operation in rapid coarse filtration mode S301: Fan Control: Control module output commands: - Axial flow fan start - Dual centrifugal fans shut down; S302: Airflow path control: External air → primary filter element → axial flow fan → side air duct → part of the airflow passes through the air duct → filter plate → all airflow is discharged from the left / right air outlet of the main unit; S303: Operation status feedback: The function display screen / APP shows "Fast coarse filtration mode", and simultaneously displays the real-time PM10 concentration and purification coverage range of 15-20㎡, updating once every 30 seconds; S304: Mode switching detection: Continuously detect S102 and S103: - If the data meets S202 or "Deep Purification" is manually selected → jump to S401 - If the data recovers to "PM10≤50μg / m³" → jump to S501 standby; (3.2) Deep purification mode operation S401: Fan Control: Control module output commands: - Axial fan start - Dual centrifugal fan start, real-time monitoring of load current, stabilizing at 1.2-1.5A, if >2A, automatically reduce speed and prompt "Fan overload"; S402: Airflow Path and Purification Control: Outside air → Primary filter → Axial fan → Side duct → Most airflow → Duct outlet → Centrifugal fan inlet → Small portion of airflow → Duct → Filter plate → Centrifugal fan inlet → Centrifugal fan pressurization → Secondary filter: HEPA filters intercept PM2.5 / PM1 + activated carbon adsorbs formaldehyde / TVOC → UV sterilization module: Sterilization rate ≥99% → Negative ion generator → Air guide plate → Indoor areas; S403: Operation status feedback: The function display screen / APP displays "Deep Purification Mode", and synchronously displays real-time PM2.5, formaldehyde concentration, CADR value: 200-220m³ / h, purification coverage area: 30-40㎡, and updates once every 30 seconds; S404: Mode switching detection: Continuously detect S102 and S103: - If the data meets S201 and there is no manual command → jump to S301 - If the data recovers to "PM2.5≤35μg / m³ and formaldehyde≤0.08mg / m³" → jump to S501 - If "rapid coarse filtration" is manually selected → jump to S301; (4) Standby and Termination Phase S501: Enter standby mode: When the air quality returns to the standard, i.e. PM10≤50μg / m³, PM2.5≤35μg / m³, formaldehyde≤0.08mg / m³, and there is no manual command, the control module shuts down the axial flow fan, dual centrifugal fans, and ultraviolet sterilization module, and only keeps the air detection module, which collects data once every 30 seconds and displays "standby" on the screen; S502: Process Termination: When the user presses and holds the "Power Off" button or the APP sends a "Power Off" command, the device loses power, all modules stop running, and the process terminates.

10. The operating method according to claim 9, characterized in that: It also includes a filter life management phase, which includes the following steps: S601: Filter Cartridge Life Calculation: The control module accumulates the purification volume in real time and calculates the remaining life of three types of filter cartridges based on the preset algorithm: CCM value / rated total purification volume: - Primary filter cartridge: washable, no lifespan value, only the cleaning cycle is indicated - Filter screen: rated lifespan corresponds to CCM value, an alert is triggered when the remaining lifespan is <10% - Secondary filter cartridge: rated lifespan corresponds to CCM value, an alert is triggered when the remaining lifespan is <10%). S602: Maintenance reminder trigger: - Primary filter element: "Clean recommended" will be displayed on the screen / APP every 7 days. - Filter screen / secondary filter element: When the remaining life is <10%, the display will light up red and the APP will push a notification, prompting "Filter element needs to be replaced". S603: Reset after maintenance: After the user completes the primary filter cleaning or filter replacement, the control module will reset the corresponding filter's cumulative CCM value and recalculate the lifespan by clicking the "Reset" button or "Reset Lifespan" in the APP.

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