Axial layering and pressure decreasing type pneumatic unblocking device and control method

Abstract

The invention discloses an axial layering and pressure decreasing type pneumatic unblocking device and a control method. The axial layering and pressure decreasing type pneumatic unblocking device comprises a stock bin, a radar level gage, an air compressor, a main pipeline, a multi-layer flow assisting pipeline set, a pressure adjusting assembly, a nozzle and a control valve. A radar level gage is mounted at the top of the stock bin and is linked with the high-speed pulse electromagnetic valve through a controller; flow assisting pipelines are laid on the main pipeline along the outer wall of the stock bin in a layered mode, each layer of pipeline is connected with an electromagnetic proportional pressure reducing valve and a pressure transmitter through a branch pipe, the axial pressure gradient is formed, and each layer is matched with a corresponding duckbilled structure and a corresponding rubber valve to improve the flow state stability. According to the control method, the injection modes are dynamically switched based on the radar material level change rate and include point-by-point injection, section-by-section injection and layer-by-layer injection. The material compaction gradient is matched through axial pressure layering, radar feedback accurate control is combined, the blockage clearing efficiency and the energy utilization rate are obviously improved, and the device is suitable for stock bin flow aiding in the industries of metal and nonmetal mines, cement, grain, chemical engineering and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of powder storage and blockage removal, and specifically provides an axial layered and pressure decreasing pneumatic blockage removal device and a control method therefor. Background Art

[0002] Affected by the properties of materials, the structure of the silo and other factors, it is very difficult for bulk materials to flow uniformly, regularly and orderly under gravity in a container. In most cases, local materials flow along the center of gravity formed by the discharge port, greatly reducing the effective volume of the silo. The main reason for this phenomenon is that materials are blocked in the silo, such as arching, bridging, and sticking.

[0003] There are many pneumatic blockage removal and flow assistance methods in the prior art. For example, Chinese Patent CN219688131U discloses a silo cleaning device for a quadrangular pyramid-shaped silo, which solves the silo blockage by arranging an annular pipeline for flow assistance air path and nozzles on the silo wall of the quadrangular pyramid-shaped silo and injecting compressed air into the silo. However, most of the prior art has the following defects:

[0004] (1) Single pressure distribution: Traditional pneumatic blockage removal devices adopt a uniform pressure design, which cannot match the density gradient distribution of the materials in the silo, resulting in insufficient blockage removal energy at the bottom layer and energy waste at the top layer (the bottom layer has a high density and the top layer is loose);

[0005] (2) Unsatisfactory blockage removal effect: A single blowing pressure may cause large fluidity in the upper layer, small or even no fluidity in the lower layer, and the flow of materials is disordered, resulting in an unsatisfactory blockage removal effect;

[0006] (3) Low energy consumption efficiency: The gas consumption for a single cycle of blockage removal operation reaches 15 - 20 m³ (under a pressure of 0.7 MPa), and the energy utilization rate may be less than 50%.

[0007] In addition, the prior art relies on a single sensor (such as a pressure switch) to judge blockage, with a high misjudgment rate, and the spraying mode is fixed, which is likely to cause disturbance to the flow state of materials. Summary of the Invention

[0008] The purpose of the present invention is to provide an axial layered and pressure decreasing pneumatic blockage removal device and a control method therefor, which achieve precise blockage removal by matching the axial pressure layer with the density gradient of the materials in the silo, feedback of the radar level change rate and dynamic switching of the spraying mode, so as to improve the blockage removal efficiency, blockage removal effect and utilization rate of air kinetic energy, and avoid disturbance to the flow state of materials, thereby solving the deficiencies of the prior art.

[0009] To achieve the above purpose, the present invention provides the following technical solutions:

[0010] An axial layered and pressure decreasing pneumatic blockage removal device, comprising:

[0011] A silo, at least one radar level gauge is installed on the top of the silo, and the radar level gauge is signal-connected to a PLC controller;

[0012] An air compressor, the output end of the air compressor is connected to the input end of an air tank through a pipeline, and the outlet end of the air tank is successively connected in series with an electric ball valve and a check valve;

[0013] A main pipeline, the outlet end of the check valve is connected to the inlet of the main pipeline, and the main pipeline is provided with branch main pipelines from the bottom to the top along the side of the silo;

[0014] A silo wall flow-aid pipeline group, including 3 - 5 layers of flow-aid pipelines arranged horizontally around the outer wall of the silo, the axial distance between each layer of flow-aid pipelines is 1.2 - 1.5 m, each layer of flow-aid pipelines is evenly distributed into four sections along the circumferential direction, and each section of flow-aid pipeline is vertically connected to the branch main pipeline through a branch pipe;

[0015] A pressure regulating component, a pilot-operated electromagnetic proportional reducing valve and a pressure transmitter are successively arranged in series on each branch pipe, wherein the outlet pressure of the bottommost layer is set to 2.0 - 2.5 MPa, the topmost layer is set to 0.8 - 1.0 MPa, the pressure setting value of the middle layer decreases arithmetically according to the pressure difference between the bottommost layer and the topmost layer, the pressure of the nth layer = the pressure of the bottommost layer - (n - 1) × tolerance, and the tolerance = (the pressure of the bottommost layer - the pressure of the topmost layer) / (the number of layers - 1);

[0016] An injection unit, 4 - 6 nozzles are installed at intervals on each section of flow-aid pipeline, and the nozzles penetrate the silo wall plate and extend into the interior by 50 - 80 mm;

[0017] A control valve, a high-speed pulse solenoid valve is arranged at the connection of each nozzle and the flow-aid pipeline, and is used to control the start and stop of injection.

[0018] Further, the installation angle of the nozzle meets the following conditions: the injection axis of the bottommost layer nozzle is parallel to the silo wall and downward; from the bottom layer to the top layer, the included angle between the injection axes of the nozzles of each adjacent two layers and the silo wall increases by 10 - 15°.

[0019] Further, the installation quantity of the radar level gauge is set according to the size of the silo: when the side length or diameter of the silo is less than 6 m, 1 - 2 radar level gauges are installed; when the side length or diameter of the silo is greater than or equal to 6 m, 2 - 4 radar level gauges are installed and evenly distributed.

[0020] Further, the end of the nozzle is of a duckbill-shaped structure, the opening width of the valve nozzle is 15 - 20 mm, and a rubber duckbill valve is inlaid inside.

[0021] Further, the response time of the high-speed pulse solenoid valve is less than 50 ms, and it is controlled in linkage with the electromagnetic proportional reducing valve by the PLC controller to realize synchronous regulation of pressure - flow.

[0022] The present invention provides another technical solution: a control method for an axial layered and pressure decreasing pneumatic plugging removal device, comprising the following steps:

[0023] S1: Real-time collect the material level height data in the silo through a radar level gauge, and calculate the material level change rate ΔL'; S2: Compare ΔL' with a preset reference change rate ΔL:

[0024] 1. When ΔL' > 0.9ΔL, enter the point-by-point injection mode;

[0025] 2. When 0.5ΔL ≤ ΔL' ≤ 0.9ΔL, enter the section-by-section injection mode;

[0026] 3. When ΔL' < 0.5ΔL, enter the layer-by-layer injection mode;

[0027] S3: Control the opening and closing sequence of the high-speed pulse solenoid valve according to the selected mode:

[0028] Point-by-point injection mode: Open and close a single nozzle in sequence according to the number, with an injection time of 1 - 2 seconds and an interval time of 30 - 60 seconds;

[0029] Section-by-section injection mode: Open and close the nozzles in the same section simultaneously within the layer, with an injection time of 2 - 3 seconds and an interval time of 60 - 120 seconds;

[0030] Layer-by-layer injection mode: Open and close all nozzles simultaneously in the layer, with an injection time of 3 - 5 seconds and an interval time of 300 - 600 seconds;

[0031] S4: Set the cyclic working time, and perform the corresponding injection operation within the cyclic working time;

[0032] S5: When the cyclic working time is full, end the automatic plugging removal control mode or enter the next automatic plugging removal control mode.

[0033] Further, the reference change rate ΔL in S2 is dynamically calibrated in the following manner: Calibrate the zero point under the no-load state of the silo; When discharging without blockage under the full-load state, record the material level drop rate once every 24 hours, and take the average value of 1 continuous hour as ΔL.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. For the axial layered and pressure decreasing pneumatic plugging removal device and control method of the present invention, the axial layered pressure design is adopted to significantly improve the energy density at the bottom layer, and the overall plugging removal efficiency is significantly improved compared with the traditional equal pressure arrangement.

[0036] 2. For the axial layered and pressure decreasing pneumatic plugging removal device and control method of the present invention, the pressure gradient of the axial layer can better match the density of the material, and the utilization rate of air kinetic energy is improved.

[0037] 3. The axial layer-by-layer and pressure-decreasing pneumatic plugging removal device and control method of the present invention improve the precise control of the plugging removal mode selection and the plugging removal efficiency by dynamically adjusting the reference of the radar material level.

[0038] 4. The axial layer-by-layer and pressure-decreasing pneumatic plugging removal device and control method of the present invention make the falling trajectory of the material stable and orderly by the increasing design of the nozzle angle, reducing the flow state disturbance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the overall structure of the pneumatic plugging removal device of the present invention;

[0040] Figure 2 It is a schematic diagram of the axial layer-by-layer and segmented of the pneumatic plugging removal device of the present invention;

[0041] Figure 3 It is a schematic diagram of the connection of the main pipeline, branch pipeline and bin wall flow-aiding pipeline of the pneumatic plugging removal device of the present invention;

[0042] Figure 4 It is a schematic diagram of the installation angle of the nozzle of the pneumatic plugging removal device of the present invention;

[0043] Figure 5 It is a schematic diagram of the structure of the duckbill nozzle of the present invention;

[0044] Figure 6 It is a logic flow chart of the control method of the present invention.

[0045] In the figure: 1. Bin; 2. Radar level gauge; 3. Air compressor; 4. Air tank; 5. Electric ball valve; 6. Check valve; 7. Main pipeline; 7'. Branch main pipeline; 8. Bin wall flow-aiding pipeline group; 9. Branch pipeline; 10. Electro-magnetic proportional pressure reducing valve; 11. Pressure transmitter; 12. High-speed pulse solenoid valve; 13. Nozzle; 14. PLC controller; 15. Rubber duckbill valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] Please refer to Figures 1-5, in the embodiment of the present invention, an axial layered and pressure decreasing pneumatic plug clearing device is provided, which includes a silo 1. A radar level gauge 2 is installed at the top of the silo 1. The installation quantity of the radar level gauge 2 is set according to the size of the silo 1: when the side length or diameter of the silo 1 is less than 6m, 1 - 2 radar level gauges 2 are installed at the center position of the feed inlet of the silo 1; when the side length or diameter of the silo 1 is greater than or equal to 6m, 2 - 4 radar level gauges 2 are installed, and the level heights of the installation positions are representative and evenly distributed.

[0048] The axial layered and pressure decreasing pneumatic plug clearing device of the present invention further includes an air compressor 3. The air compressor 3 is a screw air compressor with a rated working pressure of 2.5MPa, and the loading pressure and unloading pressure are adjustable; the output end of the air compressor 3 is connected to the input end of an air tank 4 through a pipeline. The volume of the air tank 4 is preferably 10 - 15 cubic meters. When the installation space is limited, two or more air tanks can be connected in parallel. Its outlet end is successively connected in series with an electric ball valve 5 and a check valve 6. The electric ball valve 5 is used to cut off the on - off of the gas source device and the subsequent pipeline air flow, and the check valve 6 is used to prevent backflow.

[0049] Based on the above - mentioned embodiment, in the present invention, a main pipeline 7 is laid at the bottom end of the silo 1. The air inlet port of the main pipeline 7 is connected to the outlet section of the check valve 6; the main pipeline 7 is provided with branch main pipelines 7' along the side of the silo 1 from bottom to top; a silo wall flow - assisting pipeline group 8 is arranged on the silo wall of the silo 1. The silo wall flow - assisting pipeline group 8 includes 3 - 5 layers of flow - assisting pipelines A, B, C, and D arranged horizontally around the outer wall of the silo. The axial distance between each layer of flow - assisting pipelines is 1.2 - 1.5m. Each layer of flow - assisting pipelines is evenly distributed into 4 sections along the circumferential direction. Each section of the flow - assisting pipeline is vertically connected to the branch main pipeline 7' through a branch pipe 9. Among them, a pressure - regulating component is arranged on the branch pipe 9. A pilot - type electro - magnetic proportional pressure reducing valve 10 and a pressure transmitter 11 are successively arranged in series on each branch pipe 9. The control accuracy of the electro - magnetic proportional pressure reducing valve 10 is ±0.5%FS. Specifically, the pressure setting of the electro - magnetic proportional pressure reducing valve 10 is as follows: the outlet pressure of the bottom - most layer is set to 2.0 - 2.5MPa, the top - most layer is set to 0.8 - 1.0MPa, the pressure setting value of the middle layer decreases arithmetically with the pressure difference between the bottom - most layer and the top - most layer. The pressure of the nth layer = the pressure of the bottom - most layer - (n - 1)×tolerance, and the tolerance = (the pressure of the bottom - most layer - the pressure of the top - most layer) / (the number of layers - 1); for example, the pressure of the first - layer flow - assisting pipeline A is set to 2.5MPa, the pressure of the second - layer flow - assisting pipeline B is set to 2.0MPa, the pressure of the third - layer flow - assisting pipeline C is set to 1.5MPa, and the pressure of the fourth - layer flow - assisting pipeline D is set to 1.0MPa.

[0050] In the embodiment of the present invention, a nozzle 13 is installed in a hole in the wall plate of the silo 1, and the nozzle 13 penetrates the silo wall and extends into the interior by 50 to 80 mm; 4 to 6 nozzles 13 are installed on each section of the flow-aiding pipe at intervals, and the spacing between adjacent nozzles 13 is preferably 600 to 1000 mm; the end of the nozzle 13 is forged into a duckbill shape, and the opening width of the duckbill valve mouth is 15 to 20 mm. A rubber duckbill valve 15 is embedded in the nozzle 13, and the two are interference fit. The installation angle of the nozzle 13 at each layer meets the following conditions: the spray axis of the nozzle 13 at the bottom layer is parallel to the silo wall and downward; from the bottom layer to the top layer, the angle between the spray axis of the nozzle 13 of each adjacent layer and the silo wall increases by 10-15°; for example, all the nozzles 13 of the first layer of the flow-aiding pipeline A are parallel to the silo wall, and the nozzles are facing downward; all the nozzles 13 of the second layer of the flow-aiding pipeline B are at an angle of 15° to the silo wall, and the nozzles are facing downward; all the nozzles 13 of the third layer of the flow-aiding pipeline C are at an angle of 30° to the silo wall, and the nozzles are facing downward; all the nozzles 13 of the fourth layer of the flow-aiding pipeline D are at an angle of 45° to the silo wall, and the nozzles are facing downward. A larger angle will result in faster velocity decay, but a wider coverage area, which is suitable for loose materials at the top of the silo 1; a smaller angle maintains a higher velocity and impact force, which is suitable for the dense area at the bottom of the silo 1.

[0051] The present invention connects the nozzle 13 with each section of the flow-aiding pipeline through a connecting pipe, and a high-speed pulse solenoid valve 12 is arranged on the connecting pipe. The response time of the high-speed pulse solenoid valve 12 is less than 50ms, and the high-speed pulse solenoid valve 12 is controlled by the PLC controller 14 in linkage with the electromagnetic proportional pressure reducing valve 10 to achieve pressure-flow synchronization regulation. Among them, the PLC controller 14 includes a PID controller and a PWM controller. The pressure regulation is realized by the PID controller, and the actual pressure detected by the pressure transmitter 11 is compared with the set pressure, the deviation value is calculated, and the opening of the electromagnetic proportional pressure reducing valve 10 is adjusted according to the deviation size; for example, when it is detected that the pressure of a certain layer is lower than the set value (such as 2.0MPa), the PID controller automatically increases the opening of the electromagnetic proportional pressure reducing valve 10 to quickly restore the pressure. Among them, the flow regulation can be realized by pulse width modulation (PWM), and the total amount of gas injection is controlled by adjusting the switching time ratio (duty cycle) of the high-speed pulse solenoid valve 12; for example, in the case of severe blockage, the PLC controller 14 sets the injection time to 5 seconds, with an interval of 30 seconds to ensure that the high-pressure gas fully impacts the dense material. The PID controller ensures that the pressure of each layer accurately matches the set value, and the PWM controller synchronously adjusts the airflow injection duration. The two work together to achieve "stable pressure and flow on demand" and efficient blockage clearing.

[0052] See also Figure 6 , in order to further better explain the above embodiments, the present invention also provides a control method for an axially layered, pressure-decreasing pneumatic blockage clearing device, including a manual blockage clearing control mode and an automatic blockage clearing control mode;

[0053] Among them, in the manual blockage clearing control mode, the corresponding blocked area can be targeted for blockage clearing in combination with the display of the radar level gauge 2.

[0054] In the automatic blockage clearing control mode, the following steps are included:

[0055] S1: Real-time collect the level height data through the radar level gauge 2, and calculate the radar level change rate ΔL’, ΔL’ = dL / dt; S2: Compare ΔL’ with the preset reference change rate ΔL (wherein, the reference change rate ΔL is dynamically calibrated in the following way: calibrate the zero point in the no-load state of the silo 1; when discharging without blockage at full load, record the level drop rate every 24 hours, and take the average value of 1 continuous hour as ΔL):

[0056] (1) When ΔL’ > 0.9ΔL, enter the point-by-point injection mode;

[0057] (2) When 0.5ΔL ≤ ΔL’ ≤ 0.9ΔL, enter the section-by-section injection mode;

[0058] (3) When ΔL’ < 0.5ΔL, enter the layer-by-layer injection mode;

[0059] S3: Control the opening and closing sequence of the high-speed pulse solenoid valve 12 according to the selected mode:

[0060] Point-by-point injection mode: Number all the nozzles 13 of the silo 1 one by one from the bottom layer to the top layer. Select a reference for the nozzles 13 in the same layer and number them in a clockwise or counterclockwise direction; for example, first number the nozzles 13 in the A-1 section, A-2 section, A-3 section, and A-4 section of the first-layer auxiliary flow pipeline A in a counterclockwise direction for the same-layer numbering sequence, and then number them layer by layer in the order of the first layer, the second layer, the third layer, and the fourth layer; in the point-by-point injection mode, open and close the single nozzles 13 in ascending order of the numbers until all the nozzles 13 are sprayed for one cycle; the spraying time of a single nozzle 13 is 1 - 2 seconds, and the interval time is 30 - 60 seconds;

[0061] Section-by-section injection mode: Spray the auxiliary flow pipelines section by section from the bottom layer to the top layer. First spray the bottom layer, and then spray section by section in a clockwise or counterclockwise direction. When spraying, all the nozzles 13 in the same section are sprayed simultaneously. After the lower layer is sprayed, proceed to the upper layer in turn until the top layer is sprayed and completed for one cycle; for example, first spray the A-1 section, A-2 section, A-3 section, and A-4 section in the first-layer auxiliary flow pipeline A section by section, and then spray the sections in the second layer, the third layer, and the fourth layer in turn until the last section of the auxiliary flow pipeline is sprayed and completed for one cycle; in the section-by-section injection mode, open and close the nozzles 13 in the same section in the same layer simultaneously, the spraying time is 2 - 3 seconds, and the interval time is 60 - 120 seconds;

[0062] Layer-by-layer spraying mode: Spraying is carried out layer by layer from the bottom layer to the top layer. First, all segments of the bottom layer are sprayed simultaneously, and then it progresses to the upper layers in sequence. When the spraying of the top layer is completed, it is one cycle; that is, spraying is carried out layer by layer in the order of the flow-aiding pipeline A, the flow-aiding pipeline B, the flow-aiding pipeline C, and the flow-aiding pipeline D; in the layer-by-layer spraying mode, all nozzles 13 are opened and closed simultaneously by layer, the spraying time is 3 - 5 seconds, and the interval time is 300 - 600 seconds;

[0063] Step S4: Set the cycle working time of this automatic plugging removal control on the control interface, and perform corresponding spraying operations within the cycle working time;

[0064] Step S5: When the cycle working time is up, end the automatic plugging removal control mode or enter the next automatic plugging removal control mode.

[0065] By comparing the test situations of the traditional pressure equalizing plugging removal device and the present invention under the same working conditions, the material is iron ore powder with a particle size of less than 3 mm after high-pressure roller grinding, the water content is 6%, and the structure of the silo 1 is a steel silo with a cylindrical upper part and a quadrangular pyramid lower part. The present invention can shorten the plugging removal time from 8 - 10 minutes to within 5 minutes by the methods of axial stratification (axially divided into 4 layers) and pressure reduction (high pressure at the bottom layer and low pressure at the top layer), which is nearly 50% improvement; the gas consumption for solving plugging once is reduced from 20 m³ to 12 m³, saving 40% of the energy consumption, and greatly improving the plugging removal work efficiency.

[0066] In summary: An axial stratification and pressure reduction type pneumatic plugging removal device and control method provided by the present invention, through axial pressure stratification matching the material density gradient and combined with precise control by radar feedback, have obvious improvements in both plugging removal efficiency and energy utilization rate compared with traditional devices, and are applicable to the flow-aiding of silos in industries such as metal and non-metal mines, cement, grain, and chemical industries.

[0067] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. An axial layered and pressure decreasing pneumatic plug cleaning device, characterized in that, Comprising: A silo (1), at least one radar level gauge (2) is installed on the top of the silo (1), and the radar level gauge (2) is signal-connected to a PLC controller (14); An air compressor (3), the output end of the air compressor (3) is connected to the input end of an air tank (4) through a pipeline, and the outlet end of the air tank (4) is sequentially connected in series with an electric ball valve (5) and a check valve (6); A main pipeline (7), the outlet end of the check valve (6) is connected to the inlet of the main pipeline (7), and a branch main pipeline (7') is arranged on the side of the silo (1) from bottom to top along the main pipeline (7); A group of bin wall flow-aiding pipelines (8), including 3 - 5 layers of flow-aiding pipelines arranged horizontally around the outer wall of the silo (1), the axial distance between each layer of flow-aiding pipelines is 1.2 - 1.5 m, each layer of flow-aiding pipelines is evenly distributed into four sections along the circumferential direction, and each section of flow-aiding pipeline is vertically connected to the branch main pipeline (7') through a branch pipe (9); A pressure regulating assembly, a pilot-operated electromagnetic proportional reducing valve (10) and a pressure transmitter (11) are sequentially arranged in series on each branch pipe (9), the outlet pressure of the bottom layer is set to 2.0 - 2.5 MPa, the top layer is set to 0.8 - 1.0 MPa, the set pressure value of the middle layer decreases arithmetically according to the pressure difference between the bottom layer and the top layer, the pressure of the nth layer = the pressure of the bottom layer - (n - 1) × tolerance, and the tolerance = (the pressure of the bottom layer - the pressure of the top layer) / (the number of layers - 1); An injection unit, 4 - 6 nozzles (13) are installed at intervals on each section of flow-aiding pipeline, and the nozzles (13) penetrate the wall plate of the silo (1) and extend into the interior by 50 - 80 mm; A control valve, a high-speed pulse solenoid valve (12) is arranged at the connection of each nozzle (13) and the flow-aiding pipeline, and is used to control the start and stop of injection.

2. The axial layer-by-layer and pressure-decreasing pneumatic plug cleaning device according to claim 1, wherein: The installation angle of the nozzle (13) satisfies the following conditions: the injection axis of the bottom layer nozzle (13) is parallel to the bin wall and downward; from the bottom layer to the top layer, the included angle between the injection axes of every two adjacent layers of nozzles (13) and the bin wall increases by 10 - 15°.

3. The axial layered and pressure decreasing pneumatic plug cleaning device according to claim 1, wherein: The installation quantity of the radar level gauge (2) is set according to the size of the silo (1): when the side length or diameter of the silo (1) is less than 6 m, 1 - 2 radar level gauges (2) are installed; when the side length or diameter of the silo (1) is greater than or equal to 6 m, 2 - 4 radar level gauges (2) are installed and evenly distributed.

4. The axial layering and pressure decreasing type pneumatic plug clearing device according to claim 1, wherein: The end of the nozzle (13) is a duckbill-shaped structure, the opening width of the valve nozzle is 15 - 20 mm, and a rubber duckbill valve (15) is inlaid inside.

5. The axial layered and pressure decreasing pneumatic plug clearing device according to claim 1, characterized in that: The response time of the high-speed pulse solenoid valve (12) is less than 50 ms, and it is controlled in linkage with the electromagnetic proportional reducing valve (10) by the PLC controller (14) to realize synchronous regulation of pressure - flow.

6. A control method for an axial layered and pressure decreasing pneumatic plug cleaning device as claimed in claim 1, characterized in that: Including the following steps: S1: Real-time collect the material level height data in the silo (1) through the radar level gauge (2), and calculate the material level change rate ΔL'; S2: Compare ΔL' with a preset reference change rate ΔL: (1) When ΔL' > 0.9ΔL, enter the point-by-point injection mode; (2) When 0.5ΔL ≤ ΔL' ≤ 0.9ΔL, enter the section-by-section injection mode; (3) When ΔL' < 0.5ΔL, enter the layer-by-layer injection mode; S3: Control the opening and closing sequence of the high-speed pulse solenoid valve (12) according to the selected mode: Point-by-point injection mode: Open and close individual nozzles (13) in sequence according to the numbering, with an injection time of 1 - 2 seconds and an interval time of 30 - 60 seconds; Segment-by-segment injection mode: Open and close the nozzles (13) in the same segment simultaneously within a layer, with an injection time of 2 - 3 seconds and an interval time of 60 - 120 seconds; Layer-by-layer injection mode: Open and close all nozzles (13) simultaneously for each layer, with an injection time of 3 - 5 seconds and an interval time of 300 - 600 seconds; S4: Set the cyclic working time, and perform the corresponding injection operation within the cyclic working time; S5: When the cyclic working time is up, end the automatic blockage clearing control mode or enter the next automatic blockage clearing control mode.

7. The control method of an axial layered and pressure decreasing pneumatic plug clearing device as claimed in claim 6, wherein: The reference change rate ΔL in S2 is dynamically calibrated in the following way: Calibrate the zero point in the no-load state of the silo (1); When discharging without blockage at full load, record the material level decline rate every 24 hours, and take the average value of 1 continuous hour as ΔL.

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