A swirl-type reverse flow preventing adjustable dust generator

Abstract

The application discloses a vortex type anti-backflow adjustable dust generator and relates to the field of gas-solid two-phase flow experimental equipment, which comprises a channel violent fan, a gas dust mixing mechanism, a feeding mechanism and a storage mechanism, wherein the gas dust mixing mechanism comprises a dust main mixing area, an upper air inlet, a lower air inlet and an air outlet; the dust main mixing area is a cylindrical shell structure; the upper air inlet and the lower air inlet are symmetrically arranged on the two sides of the outer circle of the dust main mixing area; and the air outlet is arranged on the middle part of the side of the dust main mixing area; the quantitative feeding structure of the servo deceleration motor driving variable pitch screw is adopted to replace the traditional gravity type free feeding mode; the PLC control system is relied on to realize the continuous adjustment of the rotation speed with an ultra-high resolution of 0.1 rpm; the dust feeding flow of different experimental conditions is accurately matched; the disadvantages of the gravity feeding affected by the friction force of dust particles, the structure of the storage bin and the material accumulation state are effectively avoided; and the problems of fast and slow feeding, material interruption and material accumulation are eliminated.

Description

Technical Field

[0001] This invention relates to the technical field of gas-solid two-phase flow experimental equipment, specifically to a vortex-type anti-backflow adjustable dust generator. Background Technology

[0002] In gas-solid two-phase flow research and industrial applications, dust generators are core equipment for constructing controllable dust environments, and their performance directly affects the accuracy of dust diffusion law analysis and dust removal equipment efficiency testing. Traditional dust generators have significant drawbacks: gravity-feed generators rely on material weight for feeding, making them susceptible to particle friction and silo structure, resulting in poor feeding accuracy, large dust concentration fluctuations, and uneven mixing; while air jet feed generators improve mixing efficiency, they rely on high-pressure air sources, limiting feeding controllability and making it difficult to generate high-concentration dust environments. Existing technologies generally suffer from insufficient particle concentration uniformity, limited particle size distribution control, and inadequate characterization of gas-solid coupling mechanisms, failing to meet high-precision experimental requirements, such as dust explosion critical concentration testing or complex industrial scenario simulation. Therefore, there is an urgent need for a dust generator that offers precise feeding, uniform mixing, and strong adaptability.

[0003] To address this issue, we provide a vortex-type anti-backflow adjustable dust generator. Summary of the Invention

[0004] To address the problems of the existing technology, this invention provides a vortex-type anti-backflow adjustable dust generator. Through modular design and gas-solid coupling optimization, it solves the problems of inaccurate feeding, uneven mixing, and poor adaptability to various scenarios in traditional devices. This invention uses a stepper motor to drive the feeding screw to achieve quantitative feeding, combined with a ducted fan to provide stable airflow, achieving efficient gas-solid two-phase mixing in a closed mixing zone.

[0005] To achieve the above objectives, the present invention employs a vortex-type anti-backflow adjustable dust generator, comprising a ducted high-speed fan, a gas-dust mixing mechanism, a feeding mechanism, and a storage mechanism. The gas-dust mixing mechanism includes a main dust mixing zone, an upper air inlet, a lower air inlet, and an air outlet. The main dust mixing zone has a cylindrical shell structure. The upper and lower air inlets are symmetrically arranged on both sides of the outer ring of the main dust mixing zone, and the air outlet is located in the middle of the side of the main dust mixing zone. Two ducted violent fans are provided, and the two ducted violent fans are respectively installed at the ends of the upper air inlet and the lower air inlet, which are used to deliver vortex airflow into the main dust mixing zone and form a double-sided counter-current pressure-stabilizing airflow field. A negative pressure stationary impeller is fixedly installed inside the dust main mixing zone near the feeding end of the storage mechanism. The negative pressure stationary impeller is used to form a stable negative pressure anti-backflow zone at the feeding inlet and to build a positive air pressure gradient to block airflow backflow. The storage mechanism is used to store dust materials, and the feeding mechanism includes an adjustable speed drive component and a variable pitch screw. The variable pitch screw is set at the discharge end of the storage mechanism and is used to quantitatively and adjustablely convey dust to the main dust mixing zone.

[0006] As a further optimization of the above scheme, multiple dust mixing undulating liners are fixed at equal angles on the inner wall of the main dust mixing zone, and the dust mixing undulating liners have a concave-convex structure.

[0007] As a further optimization of the above solution, the storage mechanism includes a cover plate and a storage mechanism housing. The storage mechanism housing is provided with a dust storage area with a funnel-shaped structure and a horizontally arranged feeding mechanism channel. The bottom of the dust storage area is connected to the feeding mechanism channel. The cover plate is sealed and closed on the top of the storage mechanism housing. The feeding mechanism channel is fitted with a metal liner, and the variable pitch screw passes through the metal liner.

[0008] As a further optimization of the above solution, the adjustable speed drive component of the feeding mechanism includes a servo geared motor, a coupling, and a servo driver. The servo geared motor is connected to a variable pitch screw drive through the coupling, and the servo driver is used to drive the servo geared motor to run.

[0009] As a further optimization of the above solution, the negative pressure stationary impeller includes a disc and multiple sets of blades. The multiple sets of blades are distributed at equal angles along the axis of the disc on the side of the disc, and the disc is fitted and installed on the inner side of the feed end of the main dust mixing zone. The chassis of the negative pressure stationary impeller blocks most of the feed inlet section, and the gap between the blades allows the dust to fall by gravity and feed. The vortex airflow inside the cavity forms a local negative pressure zone at the feed end, creating a unidirectional pressure gradient where the air pressure in the storage silo is higher than the air pressure at the feed end of the mixing chamber.

[0010] As a further optimization of the above solution, an intelligent detection and control component is also included, which includes a PLC control unit, an aerosol concentration detection component, and an intracavitary pressure detection component. The aerosol concentration detection component includes a laser aerosol concentration sensor embedded in the inner wall of the air outlet, used to collect and output dust aerosol concentration data in real time. The cavity pressure detection component includes a first negative pressure sensor and a second negative pressure sensor. The first negative pressure sensor is used to collect negative pressure data in the anti-backflow area next to the negative pressure stationary impeller, and the second negative pressure sensor is used to collect reference air pressure data for the entire dust main mixing cavity. The laser aerosol concentration sensor, the first negative pressure sensor, and the second negative pressure sensor are all electrically connected to the PLC control unit.

[0011] As a further optimization of the above solution, a variable frequency drive component is also included. The variable frequency drive component includes two sets of variable frequency drivers. The two sets of variable frequency drivers are electrically connected to two ducted high-speed fans respectively, and both sets of variable frequency drivers are connected to a PLC control unit. The PLC control unit synchronously or differentially fine-tunes the output wind speed of the two ducted violent fans to maintain a stable balance of the opposing airflow field on both sides.

[0012] As a further optimization of the above solution, the PLC control unit has a built-in PID closed-loop calculation module and a multi-parameter automatic calibration subroutine, and an external human-machine interaction touch screen. The human-machine interface touch screen is used to input preset parameters such as dust particle size, target aerosol concentration, and experimental duration. The PLC control unit has multiple sets of matching databases for wind speed, negative pressure, and screw speed corresponding to different particle sizes, enabling automatic parameter calibration upon startup and real-time closed-loop control during operation.

[0013] The vortex-type anti-backflow adjustable dust generator of the present invention has the following beneficial effects: This invention discloses a vortex-type anti-backflow adjustable dust generator. Replacing the traditional gravity-fed free-fall feeding method, it employs a servo-driven geared motor-driven variable-pitch screw quantitative feeding structure. Utilizing a PLC control system, it achieves continuously adjustable speed with ultra-high resolution of 0.1 rpm, precisely matching the dust feed flow rate under different experimental conditions. This effectively avoids the drawbacks of gravity feeding, which is affected by dust particle friction, hopper structure, and material accumulation. It eliminates problems such as inconsistent feeding speed, material interruption, and material accumulation. Simultaneously, with an intelligent PID closed-loop control mechanism, the feeding rate can be dynamically fine-tuned based on real-time aerosol concentration data, solving the problem of large fluctuations in dust output concentration in traditional equipment, ensuring the stability of dust output concentration, and meeting the stringent requirements of high-precision experiments such as dust explosion critical concentration testing. This invention features a symmetrically arranged ducted high-speed fan that can output a stable standard wind speed of 12 m / s, forming a bidirectional opposing vortex airflow field within the main dust mixing zone. Compared to the traditional single airflow jet mixing method, this results in a wider range of airflow disturbance and a more stable field. Simultaneously, multiple sets of undulating dust mixing linings with concave-convex structures are arranged at equal angles within the main dust mixing zone. This continuously cuts and disturbs the vortex airflow, breaking the laminar flow state and extending the mixing residence time of dust and airflow. This effectively suppresses dust settling and agglomeration, comprehensively optimizing the gas-solid coupling effect and achieving a uniform distribution of dust aerosol concentration across the entire region. This solves the problems of uneven mixing and imperfect gas-solid coupling mechanisms in existing technologies.

[0014] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope as a result, and that the embodiments of the present invention include many changes, modifications and equivalents within the spirit and scope of the appended claims. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the vortex-type anti-backflow adjustable dust generator in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the material storage mechanism of the present invention; Figure 3 This is a schematic diagram of the external housing structure of the gas-dust mixing mechanism of the present invention; Figure 4 This is a schematic diagram of the internal structure of the gas-dust mixing mechanism of the present invention; Figure 5 This is a schematic diagram of the feeding mechanism of the present invention; Figure 6 This is a schematic diagram of the housing structure of the material storage mechanism of the present invention; Figure 7 This is a side view of the housing of the material storage mechanism of the present invention; Figure 8 For the present invention Figure 7 Sectional view at point AA; Figure 9 This is a side view of the vortex-type anti-backflow adjustable dust generator in Embodiment 1 of the present invention; Figure 10 For the present invention Figure 9 Sectional view at point BB; Figure 11 For the present invention Figure 10 Sectional view at CC; Figure 12 This is a schematic diagram of the negative pressure stationary impeller of the present invention from one perspective; Figure 13 This is a schematic diagram of the negative pressure stationary impeller of the present invention from another perspective; Figure 14 This is a cross-sectional view of the vortex-type anti-backflow adjustable dust generator in Embodiment 2 of the present invention.

[0016] In the diagram: 1. Ducted high-pressure fan; 2. Gas-dust mixing mechanism; 3. Feeding mechanism; 4. Storage mechanism; 21. Upper air inlet; 22. Main dust mixing zone; 23. Lower air inlet; 24. Air outlet; 25. Negative pressure stationary impeller; 26. Dust mixing undulating lining; 31. Gear motor; 32. Coupling; 33. Feeding mechanism hopper shell; 34. Bearing; 35. Pitch variable screw; 36. Metal lining; 37. Feeding mechanism mixing zone shell; 41. Cover plate; 42. Storage mechanism shell; 421. Dust storage area; 422. Feeding mechanism channel; 5. Laser aerosol concentration sensor; 6. Second negative pressure sensor; 7. First negative pressure sensor; 311. Servo gear motor. Detailed Implementation

[0017] Please refer to the instruction manual appendix. Figure 1-14 The present invention provides a technical solution: a vortex-type anti-backflow adjustable dust generator, which is suitable for high-precision experimental scenarios such as industrial dust environment simulation experiments, dust removal equipment efficiency testing, dust diffusion law analysis and dust explosion critical concentration testing in fixed laboratory settings. It can stably output dust aerosols with uniform concentration, controllable particle size and no airflow backflow.

[0018] Example 1

[0019] refer to Figures 1 to 5 As shown, the vortex-type anti-backflow adjustable dust generator includes a ducted high-pressure fan 1, a gas-dust mixing mechanism 2, a feeding mechanism 3, and a storage mechanism 4. The ducted high-pressure fan 1 generates a rotating gas vortex. The gas-dust mixing mechanism 2 includes an upper air inlet 21, a main dust mixing zone 22, a lower air inlet 23, and an air outlet 24. The main dust mixing zone 22 has a cylindrical shell structure. The upper air inlet 21 is located on one side of the outer ring of the main dust mixing zone 22, the lower air inlet 23 is located on the other side of the outer ring of the main dust mixing zone 22, and the air outlet 24 is located on... Two ducted violent fans 1 are provided on the middle side of the main dust mixing zone 22. The two ducted violent fans 1 are respectively installed at the ends of the upper air inlet 21 and the lower air inlet 23. After generating a rotating gas vortex, the ducted violent fans 1 send the gas into the main dust mixing zone 22 through the upper air inlet 21 and the lower air inlet 23, so that the dust entering the main dust mixing zone 22 is mixed with the rotating gas vortex, and the fully mixed gas forming a dust aerosol is sprayed out from the air outlet 24. The insufficiently mixed dust continues to try to mix again in the main dust mixing zone 22.

[0020] The ducted high-pressure fan 1 provides a stable inlet wind speed of 12 m / s, forming a stable double-sided vortex airflow field. Based on the experimental particle size and concentration requirements, a dust particle size range of 5-20 μm is preset. The feed flow rate is matched by adjusting the speed of the geared motor 31. For example, the speed is matched to the output condition of medium-concentration dust of 0.1 kg / s. At the same time, the internal air pressure parameters of the dust main mixing zone 22 are calibrated to ensure that a stable negative pressure anti-backflow zone is formed at the negative pressure stationary impeller 25. The two ducted high-pressure fans 1 work together to form a double-sided vortex counter-current pressure stabilization structure. Combined with the negative pressure stationary impeller 25 to prevent backflow and stabilize pressure, and the integrated setting of variable pitch screw 35 for quantitative feeding, the industry pain point of airflow backflow in traditional equipment is completely solved from three dimensions: air pressure balance, airflow field structure, and feed sealing and pressure stabilization. It achieves high-precision dust aerosol output with no backflow, uniform concentration, controllable particle size, and adjustable flow rate, and is suitable for various laboratory precision dust simulation experiments.

[0021] Furthermore, a dust mixing undulating liner 26 is fixedly installed on the inner wall of the main dust mixing zone 22. Multiple dust mixing undulating liners 26 are provided and distributed at equal angles along the main dust mixing zone 22. The dust mixing undulating liner 26 has an undulating concave-convex structure to assist in the mixing of gas and dust. The undulating concave-convex structure can continuously cut and disturb the vortex airflow, break the laminar flow state of the airflow, prolong the mixing residence time of dust and airflow, avoid dust settling and agglomeration, and further balance the air pressure distribution in the main dust mixing zone 22 cavity, assist in stabilizing pressure and preventing backflow, and ensure the uniformity of dust mixing.

[0022] refer to Figures 5 to 13As shown, the feeding mechanism 3 is responsible for dynamically adjusting the addition of dust to the main dust mixing zone 22, and the storage mechanism 4 is responsible for storing dust for screw transfer. Specifically, the storage mechanism 4 includes a cover plate 41 and a storage mechanism housing 42. The storage mechanism housing 42 is provided with a dust storage area 421 and a feeding mechanism channel 422. The dust storage area 421 is a funnel-shaped trough structure, and the feeding mechanism channel 422 is a horizontally arranged channel structure. The bottom of the dust storage area 421 is connected to the feeding mechanism channel 422. The cover plate 41 is used to secure the dust storage area 421. The feeding mechanism 3 is mounted on top of the storage mechanism housing 42. It includes a geared motor 31, a coupling 32, a feeding mechanism hopper housing 33, a bearing 34, a variable pitch screw 35, a metal liner 36, and a feeding mechanism mixing zone housing 37. The geared motor 31 and the feeding mechanism hopper housing 33 are both mounted on the side of the storage mechanism housing 42 away from the main dust mixing zone 22. A notch is provided on the top of the feeding mechanism hopper housing 33, corresponding to the lower part of the dust storage area 421. The metal liner 36 is mounted on the feeding mechanism through... In channel 422, the feed mechanism hopper housing 33 is interposed within the metal liner 36 and the feed mechanism hopper housing 33. Two bearings 34 are provided; one bearing 34 rotatably connects one end of the variable pitch screw 35 to the feed mechanism mixing zone housing 37, which is installed at the end of the metal liner 36 near the main dust mixing zone 22. The other bearing 34 is used to connect the variable pitch screw 35 at the position where it intersects within the feed mechanism hopper housing 33. A rotating shaft is provided on the reduction motor 31. The variable pitch screw 35 is connected to the feed mechanism channel 422 via a coupling 32. The variable pitch screw 35 has an integral auger structure on its outer ring at the section in the feed mechanism channel 422. The dust storage area 421 is used to store dust. The dust falls into the feed mechanism hopper shell 33 through a notch. When the geared motor 31 starts, it drives the variable pitch screw 35 to move actively. The auger structure on the variable pitch screw 35 transports the dust to the main dust mixing area 22. The metal liner 36 is used to reduce the friction between the variable pitch screw 35 and the wall of the feed mechanism channel 422.

[0023] A negative pressure stationary impeller 25 is also provided in the main dust mixing zone 22. The negative pressure stationary impeller 25 includes a disc and blades. Multiple blades are provided and are distributed at equal angles along the axis of the disc on the side of the disc. The disc is fitted and installed in close contact with the middle of the main dust mixing zone 22 near the storage mechanism housing 42. Dust falls into the main dust mixing zone 22 through the gaps between the blades on the negative pressure stationary impeller 25 and mixes with the gas. The negative pressure stationary impeller 25 blocks the dust inlet, which can maintain a low pressure state at the dust inlet without affecting the dust entry, reduce the pressure difference with the dust silo, and reduce the backflow of airflow into the dust silo through the dust inlet, thus preventing gas backflow.

[0024] The mechanism of negative pressure stationary impeller 25: The solid chassis of negative pressure stationary impeller 25 blocks most of the feed inlet cross section, greatly reducing the airflow channel and blocking the large-area backflow of high-pressure airflow; the vortex airflow rotates at high speed in the main dust mixing zone 22, forming a stable local negative pressure zone on the side of negative pressure stationary impeller 25 near the feed bin of storage mechanism 4, so that the air pressure at the feed inlet is lower than the air pressure inside storage mechanism 4, forming a positive air pressure gradient, and the airflow can only flow unidirectionally from storage bin to mixing chamber, eliminating the backflow problem of high-pressure airflow in the main dust mixing zone 22 rushing back into storage mechanism 4; the blade gap can ensure that the dust falls normally under the action of gravity and feeds without affecting the feeding efficiency, achieving the anti-backflow effect of "breathable without backflow, falling material without backflow".

[0025] This invention is applicable to dust simulation in fixed laboratory settings, such as dust removal equipment performance testing. The working process is as follows: Step 1, Equipment Assembly: First, fix the ducted violent fan 1, gas-dust mixing mechanism 2, feeding mechanism 3 and storage mechanism 4 to the experimental frame with bolts. Connect the variable pitch screw 35 to the shaft of the geared motor 31 to ensure that the speed is controllable (0-100rpm). The second step is parameter setting: According to the experimental requirements, the equipment operating parameters are precisely set through the supporting control system. The ducted high-speed fan 1 outputs a stable standard inlet wind speed of 12m / s to form a stable double-sided vortex airflow field. According to the experimental particle size and concentration requirements, the dust particle size range of 5-20μm is preset. The speed of the geared motor 31 is adjusted to match the feed flow rate. For example, the speed is matched to the output condition of medium-concentration dust of 0.1kg / s. At the same time, the internal air pressure parameters of the dust main mixing zone 22 are calibrated to ensure that a stable negative pressure anti-backflow zone is formed at the negative pressure stationary impeller 25. The third step is to put dust into the dust storage area 421 and close the cover 41. Fourth step, start the geared motor 31 and the ducted high-speed fan 1; Fifth step, the dust is fed quantitatively into the main dust mixing zone 22 by the variable pitch screw 35 driven by the geared motor 31; The sixth step is that the dust entering the main dust mixing zone 22 is mixed by the vortex airflow generated by the duct violent fan 1, generating a gas-solid two-phase flow. Step 7: An air outlet 24 is provided in the center of the main dust mixing zone 22, and the mixed gas is sprayed out through the air outlet 24.

[0026] Example 2

[0027] refer to Figure 14 As shown in the figure, based on Example 1, an aerosol concentration detection component, an intracavity pressure detection component, a frequency conversion drive component, a servo drive component, and a PLC control unit are added.

[0028] The aerosol concentration detection component includes a laser aerosol concentration sensor 5, which is embedded in the inner wall of the air outlet 24. The sensor probe faces the direction of the airflow from the air outlet and collects and outputs real-time aerosol dust concentration values ​​throughout the process. The sensor signal line passes through the air outlet sealing joint and is led outward to be electrically connected to the signal input terminal of the PLC control unit. The sealing joint is filled with high-temperature resistant and dustproof sealant to prevent dust from entering the line joint and causing signal short circuits and data distortion.

[0029] The cavity pressure detection assembly includes a first negative pressure sensor 7 and a second negative pressure sensor 6. The first negative pressure sensor 7 is sealed and installed on the side cavity wall of the negative pressure stationary impeller 25 in the main dust mixing zone 22, and is used to collect the negative pressure value of the anti-backflow area of ​​the feed inlet in real time. The second negative pressure sensor 6 is sealed and installed on the middle cavity wall of the main dust mixing zone 22, and is used to collect the reference air pressure of the entire mixing cavity. Both negative pressure sensors are connected to the pressure acquisition channel of the PLC control unit through dustproof signal cables.

[0030] Variable frequency drive assembly: includes a first variable frequency drive and a second variable frequency drive; the first variable frequency drive is electrically connected to the upper air inlet side duct violent fan 1, and the second variable frequency drive is electrically connected to the lower air inlet side duct violent fan 1; the communication ports of the two variable frequency drives are uniformly connected to the PLC control unit, and the PLC independently controls the output wind speed of the two duct violent fans 1, which can be adjusted synchronously or slightly differentiated to maintain the balance of the opposing airflow field of the double vortex.

[0031] Servo drive component: Replace the geared motor 31 in Example 1 with a servo geared motor 311 and a matching servo driver; the signal terminal of the servo driver is connected to the PLC control unit, and the PLC can accurately output a continuously adjustable speed command from 0 to 100 rpm to control the dust feed flow of the variable pitch screw 35, with a speed adjustment resolution of 0.1 rpm, to achieve high-precision supply of micro dust.

[0032] PLC control unit: integrates built-in PID closed-loop calculation module, multi-parameter automatic calibration subroutine, and human-machine interaction touch screen; the human-machine interaction touch screen is externally installed on the side of the equipment experimental platform. The operator can input three preset parameters through the touch screen: target dust particle size (5-20μm), target aerosol output concentration, and experimental duration; the PLC has a pre-stored database of matching wind speed, negative pressure, and screw speed for different particle sizes, and automatically retrieves the corresponding basic operating parameters after power-on.

[0033] The overall operation of the equipment is divided into two processes: the automatic calibration stage upon startup and the closed-loop stable control stage. It achieves fully automatic concentration and pressure stabilization control by relying on the coordinated action of the dual-sided vortex airflow field, the negative pressure zone of the negative pressure stationary impeller, and the variable-pitch screw feeder. First, the automatic calibration process upon startup: the operator inputs the required dust particle size and target output concentration on the human-machine interface touchscreen. The PLC retrieves the corresponding reference parameters from the built-in database and sends initial commands to the first frequency converter, the second frequency converter, and the servo driver respectively. The two ducted high-speed fans 1 output a reference inlet wind speed of 12 m / s. The servo geared motor 311 drives the variable pitch screw 35 to transport dust at the reference speed. The laser aerosol concentration sensor 5, the first negative pressure sensor 7, and the second negative pressure sensor 6 synchronously and continuously collect three sets of data: real-time concentration, inlet negative pressure, and cavity reference air pressure. The PLC collects 30 seconds of continuous data to complete the average calculation and automatically generates a three-dimensional matching curve of wind speed, negative pressure, and screw speed adapted to the current dust material, completing the equipment self-calibration and eliminating parameter deviations caused by manual adjustment.

[0034] Second, the real-time PID closed-loop control process: after calibration, the equipment enters continuous experimental operation. The sensors continuously upload detection data to the PLC in real time. The PLC compares the real-time detection values ​​with the target values ​​set by the operator through its built-in PID algorithm, and automatically adjusts the system according to three types of operating conditions: 1. Measured aerosol concentration > set target concentration: The PLC synchronously issues dual adjustment commands. On the one hand, it reduces the output speed of the servo geared motor 311 and reduces the dust feed of the variable pitch screw 35. On the other hand, it slightly reduces the output wind speed of the two ducted violent fans, reduces the intensity of the vortex airflow in the cavity, and synchronously raises the negative pressure value around the negative pressure stationary impeller 25 to reduce the rate at which dust falls from the storage mechanism 4 to the mixing cavity. The bidirectional synchronous control quickly reduces the output dust concentration until the detected concentration returns to the set range.

[0035] 2. Actual aerosol concentration < set target concentration: PLC reverse linkage adjustment slightly increases the servo motor speed to increase the feed flow rate, and simultaneously increases the wind speed of the double-sided duct fan to enhance the vortex disturbance intensity in the cavity, stabilize the negative pressure at the feed inlet, and improve the dust mixing output concentration, avoiding the continuous decrease in concentration due to ash accumulation and material consumption in the cavity during long-term experiments.

[0036] 3. Negative Pressure Abnormality Early Warning and Adjustment: When the first negative pressure sensor 7 detects that the negative pressure at the negative pressure stationary impeller 25 is lower than the safety threshold, indicating a risk of airflow backflow, the PLC prioritizes increasing the wind speed of the two ducted high-pressure fans to strengthen the double-sided counter-current vortex airflow, quickly restore the local negative pressure gradient at the feed inlet, and prevent the high-pressure airflow in the mixing chamber from flowing back into the storage silo; if the negative pressure continues to be abnormal, the touch screen will simultaneously display an audible and visual warning to prompt the operator to check for feed inlet blockage and cavity sealing leaks.

Claims

1. A vortex-type anti-backflow adjustable dust generator, comprising a ducted high-speed fan (1), a gas-dust mixing mechanism (2), a feeding mechanism (3), and a storage mechanism (4), characterized in that: The gas-dust mixing mechanism (2) includes a main dust mixing zone (22), an upper air inlet (21), a lower air inlet (23), and an air outlet (24). The main dust mixing zone (22) is a cylindrical shell structure. The upper air inlet (21) and the lower air inlet (23) are symmetrically arranged on both sides of the outer ring of the main dust mixing zone (22). The air outlet (24) is located in the middle of the side of the main dust mixing zone (22). Two duct violent fans (1) are provided, and the two duct violent fans (1) are respectively installed at the ends of the upper air inlet (21) and the lower air inlet (23) to deliver vortex airflow into the dust main mixing zone (22) and form a double-sided counter-pressure stabilizing airflow field; The dust main mixing zone (22) is fixedly provided with a negative pressure stationary impeller (25) near the feed end of the storage mechanism (4). The negative pressure stationary impeller (25) is used to form a stable negative pressure anti-backflow zone at the feed inlet and to build a positive air pressure gradient to block the backflow of airflow. The storage mechanism (4) is used to store dust materials. The feeding mechanism (3) includes an adjustable speed drive component and a variable pitch screw (35). The variable pitch screw (35) is set at the discharge end of the storage mechanism (4) and is used to quantitatively and adjustablely convey dust to the main dust mixing zone (22).

2. The vortex-type anti-backflow adjustable dust generator according to claim 1, characterized in that: Multiple dust mixing undulating liners (26) are fixed at equal angles on the inner wall of the main dust mixing zone (22), and the dust mixing undulating liners (26) have a concave-convex structure.

3. The vortex-type anti-backflow adjustable dust generator according to claim 1, characterized in that: The storage mechanism (4) includes a cover plate (41) and a storage mechanism housing (42). The storage mechanism housing (42) is provided with a dust storage area (421) with a funnel-shaped structure and a horizontally arranged feeding mechanism channel (422). The bottom of the dust storage area (421) is connected to the feeding mechanism channel (422). The cover plate (41) is sealed and covered on the top of the storage mechanism housing (42). The feeding mechanism channel (422) is fitted with a metal liner (36), and the variable pitch screw (35) passes through the metal liner (36).

4. A vortex-type anti-backflow adjustable dust generator according to claim 1, characterized in that: The adjustable speed drive assembly of the feeding mechanism (3) includes a servo geared motor (311), a coupling (32) and a servo driver. The servo geared motor (311) is connected to the variable pitch screw (35) via the coupling (32), and the servo driver is used to drive the servo geared motor (311) to run.

5. A vortex-type anti-backflow adjustable dust generator according to claim 1, characterized in that: The negative pressure stationary impeller (25) includes a disc and multiple sets of blades. The multiple sets of blades are distributed at equal angles along the axis of the disc on the side of the disc. The disc is fitted and installed on the inner side of the feed end of the dust main mixing zone (22). The chassis of the negative pressure stationary impeller (25) blocks most of the feed inlet section, and the gap between the blades allows the dust to fall by gravity and feed. The vortex airflow in the cavity forms a local negative pressure zone at the feed end, forming a unidirectional pressure gradient where the air pressure in the storage silo is higher than the air pressure at the feed end of the mixing chamber.

6. A vortex-type anti-backflow adjustable dust generator according to claim 1, characterized in that: It also includes an intelligent detection and control component, which includes a PLC control unit, an aerosol concentration detection component, and an intracavity pressure detection component; The aerosol concentration detection component includes a laser aerosol concentration sensor (5) embedded in the inner wall of the air outlet (24) for real-time acquisition and output of dust aerosol concentration data. The cavity pressure detection component includes a first negative pressure sensor (7) and a second negative pressure sensor (6). The first negative pressure sensor (7) is used to collect negative pressure data in the anti-backflow area beside the negative pressure stationary impeller (25), and the second negative pressure sensor (6) is used to collect the reference air pressure data of the entire dust main mixing cavity. The laser aerosol concentration sensor (5), the first negative pressure sensor (7), and the second negative pressure sensor (6) are all electrically connected to the PLC control unit.

7. A vortex-type anti-backflow adjustable dust generator according to claim 6, characterized in that: It also includes a frequency converter drive assembly, which includes two sets of frequency converters. The two sets of frequency converters are electrically connected to two ducted high-speed fans (1), and both sets of frequency converters are connected to a PLC control unit. The PLC control unit synchronously or differentially fine-tunes the output wind speed of the two ducted violent fans (1) to maintain a stable balance of the opposing airflow field on both sides.

8. A vortex-type anti-backflow adjustable dust generator according to claim 7, characterized in that: The PLC control unit has a built-in PID closed-loop calculation module and a multi-parameter automatic calibration subroutine, and an external human-machine interaction touch screen. The human-machine interface touch screen is used to input preset parameters such as dust particle size, target aerosol concentration, and experimental duration. The PLC control unit has multiple sets of matching databases for wind speed, negative pressure, and screw speed corresponding to different particle sizes, enabling automatic parameter calibration upon startup and real-time closed-loop control during operation.

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