Online detection device for blast furnace coal injection powder granularity

Abstract

The online detection device comprises a screening cavity, an auxiliary cavity, a bottom plate, a powder feeding mechanism, a powder discharging mechanism, a screening part and an after-screening powder weighing mechanism, the screening cavity and the auxiliary cavity are both arranged on the bottom plate, the bottom plate is arranged on the platform through a support and is fixed relative to the position of a vertical mill pulverized coal outlet pipeline, and the screening cavity is connected with the auxiliary cavity; the powder feeding mechanism is arranged at the top end of the screening cavity, the powder discharging mechanism is arranged on the auxiliary cavity, and the powder feeding mechanism and the powder discharging mechanism are both connected with a vertical mill pulverized coal outlet pipeline; and the sieving part and the sieved powder weighing mechanism are arranged on the sieving cavity. According to the invention, the efficiency of vertical mill pipeline granularity detection is improved.

Description

Technical Field

[0001] This invention relates to an online coal powder particle size detection device, and more particularly to a device capable of online detection of coal powder particle size in a coal injection system, belonging to the technical field of coal powder particle size detection equipment. Background Technology

[0002] In blast furnace pulverized coal injection (PCO) technology, the particle size of the pulverized coal produced by the pulverizing system is a key parameter affecting the injection effect and blast furnace operation. Appropriate pulverized coal particle size helps optimize combustion efficiency and control the heat release rhythm, thereby reducing fuel ratio and production costs. Currently, obtaining this parameter mainly relies on manual sampling and laboratory analysis. Operators need to collect pulverized coal samples at the vertical mill's pulverized coal outlet pipe, then transport them to the laboratory. After multiple processes such as weighing, sieving, re-weighing, and calculation, the particle size distribution results can be obtained. This process is not only cumbersome but also often time-consuming from sampling to data acquisition. This long time lag prevents production personnel from timely grasping the real-time operating status of the pulverizing system. When the pulverized coal particle size deviates from the process requirements, it cannot be quickly detected and adjusted, causing the system to operate in a suboptimal state for extended periods. Therefore, the time-consuming nature of manual sampling and analysis has become one of the main bottlenecks restricting the refined control and rapid response to changes in raw materials in the pulverizing system. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an online detection device for the particle size of pulverized coal in blast furnace injection, which can quickly detect the particle size of pulverized coal in the outlet pipe of vertical mill pulverized coal.

[0004] The problem described in this invention is solved by the following technical solution: An online detection device for pulverized coal in blast furnace includes a screening chamber, an auxiliary chamber, a bottom plate, a powder feeding mechanism, a powder discharging mechanism, a sieving section, and a post-screening powder weighing mechanism. The screening chamber and the auxiliary chamber are both mounted on the bottom plate, which is supported on a platform and fixed relative to the vertical mill's pulverized coal outlet pipe. The screening chamber and the auxiliary chamber are connected. The powder feeding mechanism is located at the top of the screening chamber, and the powder discharging mechanism is located on the auxiliary chamber. Both the powder feeding mechanism and the powder discharging mechanism are connected to the vertical mill's pulverized coal outlet pipe. The sieving section and the post-screening powder weighing mechanism are both located on the screening chamber.

[0005] The above-mentioned online detection device for pulverized coal particle size in blast furnaces includes a screening chamber comprising a first vertical plate, a second vertical plate, a third vertical plate, and a fourth vertical plate, which are connected end to end to form a square frame shape. The first vertical plate and the third vertical plate are opposite to each other. The auxiliary chamber includes a fifth vertical plate, a sixth vertical plate, and a seventh vertical plate. One side of the fifth vertical plate is aligned with the second vertical plate, one side of the sixth vertical plate is aligned with the fourth vertical plate, and the seventh vertical plate is positioned between the fifth and sixth vertical plates. Except for the third vertical plate, the bottom ends of the remaining vertical plates are all mounted on a base plate.

[0006] The aforementioned online detection device for pulverized coal particle size in blast furnace injection includes a sieving section comprising a square frame, a first weighing mechanism, a screen, and a first electric cylinder. Both the first and third vertical plates are provided with slotted holes, and the two ends of the square frame are respectively inserted into the slotted holes of the first and third vertical plates. A vibrator is provided on the end face of the square frame near the first electric cylinder, and the signal input terminal of the vibrator is connected to the signal output terminal of the CPU. Both the second and fourth vertical plates are provided with sliding grooves, and sliding strips on the outer walls of both sides of the square frame are slidably inserted into the inner walls of the second and fourth vertical plates, respectively. The sliding grooves are provided on the inner walls of the fifth and sixth vertical plates, and the sliding grooves on the fifth vertical plate are aligned with the sliding grooves on the second vertical plate, and the sliding grooves on the sixth vertical plate are aligned with the sliding grooves on the fourth vertical plate; the first weighing mechanism is set on the inner wall of the square frame, and the screen is set on the first weighing mechanism; the first electric cylinder is set on the outer wall of the first vertical plate through a bracket, and its piston rod is connected to the outer wall of the square frame, and the axis of the piston rod of the first electric cylinder is parallel to the center line of the sliding strip on the side wall of the square frame; the signal input terminal of the first electric cylinder is connected to the signal output terminal of the CPU.

[0007] The above-mentioned online detection device for pulverized coal particle size in blast furnace injection includes a first weighing mechanism comprising four weighing components, which are respectively located at the four corners of the bottom of the inner wall of a square frame. A screen is mounted on the four weighing components, with the outer wall of the screen in contact with the inner wall of the square frame. Each weighing component includes a fixed block and a first weighing device. The fixed block is located at the bottom corner of the inner wall of the square frame and has a hollow internal structure. The first weighing device is located inside the fixed block. A perforation is provided at the top of the fixed block, through which a support rod passes. The top of the support rod is connected to the bottom corner of the screen, and the bottom of the support rod is connected to the top of the first weighing device. The signal output terminal of the first weighing device is connected to the signal input terminal of the CPU.

[0008] The above-mentioned online detection device for pulverized coal particle size in blast furnace includes a weighing mechanism for the screened powder, comprising a second weighing mechanism, a bottom slide plate, a first side plate, a second side plate, and a second electric cylinder. The second electric cylinder is mounted on the outer wall of the first vertical plate, and its piston rod passes through a perforation in the side wall of the first vertical plate. The end of the piston rod of the second electric cylinder is connected to the first side plate, which is located within the screening chamber. The bottom slide plate is located between the bottom ends of the first and second side plates. The length of the bottom slide plate is equal to the distance between the first and third vertical plates. The top surfaces of the first and second side plates are flush with the bottom surface of the third vertical plate. The second weighing mechanism is mounted on the bottom slide plate. A strip-shaped hole is provided at the bottom end of the side wall of the second side plate, and a rotating shaft is provided on both sides of the inner wall of the strip-shaped hole. A flap is mounted on the rotating shaft, and the flap covers the strip-shaped hole of the second side plate.

[0009] The above-mentioned online detection device for pulverized coal particle size in blast furnace includes a second weighing mechanism comprising a weighing plate and a second weigher; the top surface of the bottom slide plate is provided with a square hole, and the second weigher is disposed on the bottom surface of the square hole, the weighing plate is disposed on each of the second weighers, and the outer wall of the weighing plate is in contact with the inner wall of the square hole of the bottom slide plate; the signal output terminal of the second weigher is connected to the signal input terminal of the CPU.

[0010] The above-mentioned online detection device for pulverized coal particle size in blast furnace injection includes a pulverizing mechanism comprising a high-pressure nitrogen source, a first solenoid valve, a duck-shaped nozzle, a pulverizing hopper, a pulverizing pipeline, a second solenoid valve, and a first check valve. A strip-shaped hole is provided at the bottom of the seventh vertical plate. The duck-shaped nozzle is located on the outer wall of the seventh vertical plate, with its end connected to the strip-shaped hole. The other end of the duck-shaped nozzle is connected to the first solenoid valve, which is connected to the high-pressure nitrogen source via a pipeline. The strip-shaped hole at the bottom of the seventh vertical plate is aligned horizontally with the strip-shaped hole on the second side plate. The end with the largest opening of the pulverizing hopper is located on the top surface of the third, fifth, sixth, and seventh vertical plates. The end with the smallest opening of the pulverizing hopper is connected to the bottom of the pulverizing pipeline, and the other end of the pulverizing pipeline is connected to the pulverized coal outlet pipeline of the vertical mill. A second solenoid valve and a first check valve are provided on the pulverizing pipeline. The signal input terminals of the first and second solenoid valves are connected to the signal output terminals of the CPU.

[0011] The above-mentioned online detection device for pulverized coal particle size in blast furnace injection includes a pulverizing mechanism comprising a top cover plate, a pulverizing pipe, a third solenoid valve, and a second check valve. The top cover plate is located at the top of a combination of a first vertical plate, a second vertical plate, a third vertical plate, and a fourth vertical plate. The pulverizing pipe is located on the top cover plate, with its bottom end extending into the screening chamber. The top end of the pulverizing pipe is connected to the pulverized coal outlet pipe of the vertical mill. Both the third solenoid valve and the second check valve are located on the pulverizing pipe. The signal input terminal of the third solenoid valve is connected to the signal output terminal of the CPU.

[0012] This invention uses a powder feeding mechanism to transport coal powder from the vertical mill's coal outlet pipe to the screening chamber. The coal powder is then screened by a screening section and a post-screening powder weighing mechanism. The weight of the screened coal powder is compared to calculate the proportion of small-particle coal powder. Finally, the coal powder is transported back to the vertical mill's coal outlet pipe through the cooperation of the powder discharge mechanism and the auxiliary chamber, thus avoiding waste. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the first three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the second three-dimensional structure of the present invention; Figure 3 This is a schematic diagram of the first three-dimensional structure of the present invention after removing the fourth and sixth vertical plates; Figure 4 This is a schematic diagram of the second three-dimensional structure of the present invention after removing the fourth and sixth vertical plates.

[0014] The following is a list of the labels in the diagram: 1. Base plate, 2. First vertical plate, 3. Second vertical plate, 4. Third vertical plate, 5. Fourth vertical plate, 6. Square frame, 7. Screen, 8. First electric cylinder, 9. Weighing component, 10. Fifth vertical plate, 11. Sixth vertical plate, 12. Seventh vertical plate, 13. Powder inlet pipe, 14. Second weighing mechanism, 15. Bottom slide plate, 16. First side plate, 17. Second side plate, 18. Second electric cylinder, 19. First solenoid valve, 20. Duck-shaped nozzle, 21. Powder outlet hopper, 22. Powder outlet pipe, 23. Top cover plate, 24. Vibrator. Detailed Implementation

[0015] See Figure 1 , 2 3 and Figure 4 The present invention includes a screening chamber, an auxiliary chamber, a base plate 1, a powder feeding mechanism, a powder discharging mechanism, a sieving section, and a post-screening powder weighing mechanism. The screening chamber and the auxiliary chamber are both mounted on the base plate 1, which is supported on a platform and fixed relative to the vertical mill's coal powder outlet pipe. The screening chamber and the auxiliary chamber are connected. Coal powder is screened and weighed in the screening chamber and then blown back to the vertical mill's coal outlet pipe in the auxiliary chamber. The powder feeding mechanism is located at the top of the screening chamber, and the powder discharging mechanism is located on the auxiliary chamber. Both the powder feeding and discharging mechanisms are connected to the vertical mill's coal powder outlet pipe. The sieving section and the post-screening powder weighing mechanism are both located on the screening chamber. The sieving section and the post-screening powder weighing mechanism work together to screen and weigh the coal powder, thereby determining the proportion of small-particle coal.

[0016] The screening chamber includes a first vertical plate 2, a second vertical plate 3, a third vertical plate 4, and a fourth vertical plate 5, which are connected end to end to form a square frame shape. The first vertical plate 2 and the third vertical plate 4 are opposite to each other. The auxiliary chamber includes a fifth vertical plate 10, a sixth vertical plate 11, and a seventh vertical plate 12. One side of the fifth vertical plate 10 is aligned with the second vertical plate 3, one side of the sixth vertical plate 11 is aligned with the fourth vertical plate 5, and the seventh vertical plate 12 is located between the fifth vertical plate 10 and the sixth vertical plate 11. Except for the third vertical plate 4, the bottom ends of the other vertical plates are all located on the base plate 1. There is a gap between the bottom end of the third vertical plate 4 and the base plate for the first side plate, the second side plate, and the bottom slide plate assembly to pass through.

[0017] The sieving section includes a square frame 6, a first weighing mechanism, a screen 7, and a first electric cylinder 8. The first vertical plate 2 and the third vertical plate 4 are each provided with strip-shaped holes, and both ends of the square frame 6 are respectively inserted into the strip-shaped holes of the first vertical plate 2 and the third vertical plate 4. Driven by the first electric cylinder, the square frame 6 can move from the sieving chamber to the auxiliary chamber for backflushing. A vibrator 24 is provided on the end face of the square frame 6 near the first electric cylinder 8, and the signal input end of the vibrator 24 is connected to the signal output end of the CPU. The vibrator 24 ensures that the coal powder on the screen is fully sieved. The second vertical plate 3 and the fourth vertical plate 5 are each provided with sliding grooves, and sliding strips on both sides of the outer wall of the square frame 6 are respectively slidably inserted into the sliding grooves on the inner walls of the second vertical plate 3 and the fourth vertical plate 5. Guided by the sliding grooves of the second, fourth, fifth, and sixth vertical plates, the square frame 6 smoothly slides into the auxiliary chamber.

[0018] The inner walls of the fifth vertical plate 10 and the sixth vertical plate 11 are both provided with sliding grooves, and the sliding groove on the fifth vertical plate 10 is aligned with the sliding groove on the second vertical plate 3, and the sliding groove on the sixth vertical plate 11 is aligned with the sliding groove on the fourth vertical plate 5; the first weighing mechanism is set on the inner wall of the square frame 6, and the screen 7 is set on the first weighing mechanism; the first weighing mechanism is used to weigh the coal powder on the screen; the first electric cylinder 8 is set on the outer wall of the first vertical plate 2 through a bracket, and its piston rod is connected to the outer wall of the square frame 6, and the axis of the piston rod of the first electric cylinder 8 is parallel to the center line of the sliding strip on the side wall of the square frame 6; the first electric cylinder drives the square frame 6 to slide along the direction of the sliding groove; the signal input terminal of the first electric cylinder 8 is connected to the signal output terminal of the CPU.

[0019] The first weighing mechanism includes four weighing components 9, which are respectively located at the four corners of the bottom of the inner wall of the square frame 6. A screen 7 is mounted on the four weighing components 9, and the outer wall of the screen 7 is in contact with the inner wall of the square frame 6. Each weighing component 9 includes a fixed block and a first weighing device. The fixed block is located at the bottom corner of the inner wall of the square frame 6 and has a hollow structure inside. The first weighing device is located inside the fixed block. A through hole is provided at the top of the fixed block, and a support rod passes through the through hole at the top of the fixed block. The top of the support rod is connected to the bottom corner of the screen 7, and the bottom of the support rod is connected to the top of the first weighing device. The signal output terminal of the first weighing device is connected to the signal input terminal of the CPU. The weight of the residual coal powder on the screen is obtained through the first weighing device, and combined with the weight of the sieved powder weighed by the second weighing mechanism 14, the percentage of sieved powder can be obtained.

[0020] The post-screening powder weighing mechanism includes a second weighing mechanism 14, a bottom slide plate 15, a first side plate 16, a second side plate 17, and a second electric cylinder 18. The second electric cylinder 18 is disposed on the outer wall of the first vertical plate 2, and its piston rod passes through a perforation in the side wall of the first vertical plate 2. The end of the piston rod of the second electric cylinder 18 is connected to the first side plate 16, which is located in the screening chamber. The action of the second electric cylinder 18 drives the assembly of the first side plate, the second side plate, the second weighing mechanism 14, and the bottom slide plate 15 to move between the screening chamber and the auxiliary chamber. The bottom slide plate 15 is located between the bottom end of the first side plate 16 and the bottom end of the second side plate 17. The length of the bottom slide plate 15 is equal to the distance between the first vertical plate 2 and the third vertical plate 4. The first side plate 16 and the second... The top surface of the side plate 17 is flush with the bottom surface of the third vertical plate 4; this ensures that when the assembly is in the screening chamber, the second side plate blocks the gap between the third vertical plate and the bottom plate, and when the assembly is in the auxiliary chamber, the first side plate blocks the gap between the third vertical plate and the bottom plate; the second weighing mechanism 14 is set on the bottom slide plate 15; the small coal powder particles after screening fall onto the second weighing mechanism for weighing; the bottom end of the side wall of the second side plate 17 is provided with a strip hole, and the inner walls of the strip hole are provided with rotating shafts on both sides, and the flap is set on the rotating shaft, the flap blocking the strip hole of the second side plate 17; on the one hand, the flap prevents the coal powder from falling off the second weighing mechanism 14, and on the other hand, it ensures that when high-pressure nitrogen is injected, the high-pressure nitrogen can smoothly lift the flap and blow the coal powder upward.

[0021] The second weighing mechanism 14 includes a weighing plate and a second weighing device; the top surface of the bottom slide plate 15 is provided with a square hole, and the second weighing device is provided on the bottom surface of the square hole. The weighing plate is provided on each of the second weighing devices, and the outer wall of the weighing plate is in contact with the inner wall of the square hole of the bottom slide plate 15; the signal output terminal of the second weighing device is connected to the signal input terminal of the CPU; the sieved coal powder is weighed on the second weighing mechanism.

[0022] The powder discharge mechanism includes a high-pressure nitrogen source, a first solenoid valve 19, a duck-shaped nozzle 20, a powder discharge hopper 21, a powder discharge pipe 22, a second solenoid valve, and a first one-way valve. The bottom end of the seventh vertical plate 12 has a strip-shaped hole. The duck-shaped nozzle 20 is located on the outer wall of the seventh vertical plate 12, with its end connected to the strip-shaped hole. The other end of the duck-shaped nozzle 20 is connected to the first solenoid valve 19, which is connected to the high-pressure nitrogen source via a pipe. The strip-shaped hole at the bottom of the seventh vertical plate 12 is aligned horizontally with the strip-shaped hole of the second side plate 17. When the second side plate is attached to the seventh vertical plate 12, the flap aligns precisely with the strip-shaped hole of the seventh vertical plate. At this time, the nitrogen gas blown in can enter the weighing plate from the flap aligning with the strip-shaped hole, causing the coal powder to move upwards.

[0023] The largest opening of the powder discharge hopper 21 is located on the top surface of the third vertical plate 4, the fifth vertical plate 10, the sixth vertical plate 11, and the seventh vertical plate 12. The upward-blown coal powder passes through the powder discharge hopper 21 and the powder discharge pipe 22 in sequence and returns to the coal powder outlet pipe of the vertical mill. The smallest opening of the powder discharge hopper 21 is connected to the bottom end of the powder discharge pipe 22, and the other end of the powder discharge pipe 22 is connected to the coal powder outlet pipe of the vertical mill. The powder discharge pipe 22 is equipped with a second solenoid valve and a first check valve. The first check valve prevents the coal powder in the coal powder outlet pipe of the vertical mill from flowing back into the powder discharge hopper 21. The signal input terminals of the first solenoid valve 19 and the second solenoid valve are connected to the signal output terminal of the CPU.

[0024] The powder feeding mechanism includes a top cover plate 23, a powder feeding pipe 13, a third solenoid valve, and a second check valve. The top cover plate 23 is located at the top of the assembly of the first vertical plate 2, the second vertical plate 3, the third vertical plate 4, and the fourth vertical plate 5. The powder feeding pipe 13 is located on the top cover plate 23, and its bottom end extends into the screening chamber. The top end of the powder feeding pipe 13 is connected to the vertical mill coal powder outlet pipe. The third solenoid valve and the second check valve are both located on the powder feeding pipe 13. The signal input end of the third solenoid valve is connected to the signal output end of the CPU. The second check valve ensures that the airflow in the screening chamber does not enter the vertical mill coal powder outlet pipe, forming a double safety measure in conjunction with the third solenoid valve.

[0025] The CPU module used in this invention is model 87C196KC.

[0026] Operating principle: This invention is activated periodically to sample, screen, weigh, and calculate the proportion of pulverized coal in the coal outlet pipe of the vertical mill; the steps are as follows; The third solenoid valve is activated to allow coal powder in the vertical mill's coal outlet pipe to enter the screen. After a period of time, the third solenoid valve is closed. Then, the vibrator 24 is activated to vibrate the square frame 6, causing the coal powder to pass through the screen 7. The screened powder falls onto the second weighing mechanism 14 for weighing. The first weighing mechanism weighs the powder on the screen, and the percentage of screened powder (i.e., coal powder with a particle size smaller than the required value) can be calculated. After the calculation is completed, the second electric cylinder 18 is activated to slide the bottom slide plate 15 until the second side plate touches the side wall of the seventh vertical plate. Then, the first solenoid valve is activated to connect the high-pressure nitrogen gas. At this time, the pressure of the high-pressure nitrogen gas is greater than the pressure of the vertical mill's coal outlet pipe. Then, the second solenoid valve is opened. High-pressure nitrogen gas in the auxiliary chamber blows the coal powder on the second weighing mechanism to move into the coal outlet pipe of the vertical mill. After a period of time, the first and second solenoid valves are closed. Then the second electric cylinder is reset. The first electric cylinder is activated to push the square frame 6 into the auxiliary chamber. Then the first and second solenoid valves are activated. High-pressure nitrogen gas blows the coal powder on the screen from bottom to top back into the coal conveying pipe of the vertical mill. The coal powder on the screen is also cleaned by backflushing. After a period of time, the first and second solenoid valves are closed, the first electric cylinder is reset, and the mill waits for the next test.

Claims

1. An online detection device for particle size of pulverized coal in blast furnace injection, characterized in that: It includes a screening chamber, an auxiliary chamber, a bottom plate (1), a powder feeding mechanism, a powder discharging mechanism, a sieving section, and a powder weighing mechanism after sieving; the screening chamber and the auxiliary chamber are both set on the bottom plate (1), which is set on the platform by a bracket and is fixed relative to the vertical mill coal powder outlet pipe, and the screening chamber is connected to the auxiliary chamber; the powder feeding mechanism is set at the top of the screening chamber, the powder discharging mechanism is set on the auxiliary chamber, and both the powder feeding mechanism and the powder discharging mechanism are connected to the vertical mill coal powder outlet pipe; the sieving section and the powder weighing mechanism after sieving are both set on the screening chamber.

2. The online detection device for pulverized coal particle size in blast furnace according to claim 1, characterized in that: The screening chamber includes a first vertical plate (2), a second vertical plate (3), a third vertical plate (4), and a fourth vertical plate (5). The four vertical plates are connected end to end to form a square frame shape. The first vertical plate (2) and the third vertical plate (4) are opposite to each other. The auxiliary chamber includes a fifth vertical plate (10), a sixth vertical plate (11), and a seventh vertical plate (12). One side of the fifth vertical plate (10) is aligned with the second vertical plate (3), one side of the sixth vertical plate (11) is aligned with the fourth vertical plate (5), and the seventh vertical plate (12) is located between the fifth vertical plate (10) and the sixth vertical plate (11). Except for the third vertical plate (4), the bottom ends of the other vertical plates are all located on the base plate (1).

3. The online detection device for pulverized coal particle size in blast furnace according to claim 2, characterized in that: The sieving section includes a square frame (6), a first weighing mechanism, a screen (7), and a first electric cylinder (8); both the first vertical plate (2) and the third vertical plate (4) are provided with strip holes, and the two ends of the square frame (6) are respectively inserted into the strip holes of the first vertical plate (2) and the third vertical plate (4); a vibrator (24) is provided on the end face of the square frame (6) near the first electric cylinder (8), and the signal input end of the vibrator (24) is connected to the signal output end of the CPU; both the second vertical plate (3) and the fourth vertical plate (5) are provided with sliding grooves, and the sliding strips on the outer walls of both sides of the square frame (6) are respectively slidably inserted into the sliding grooves on the inner walls of the second vertical plate (3) and the fourth vertical plate (5); The inner walls of the fifth vertical plate (10) and the sixth vertical plate (11) are provided with sliding grooves, and the sliding groove on the fifth vertical plate (10) is aligned with the sliding groove on the second vertical plate (3), and the sliding groove on the sixth vertical plate (11) is aligned with the sliding groove on the fourth vertical plate (5); the first weighing mechanism is set on the inner wall of the square frame (6), and the screen (7) is set on the first weighing mechanism; the first electric cylinder (8) is set on the outer wall of the first vertical plate (2) through a bracket, and its piston rod is connected to the outer wall of the square frame (6), and the axis of the piston rod of the first electric cylinder (8) is parallel to the center line of the sliding strip on the side wall of the square frame (6); the signal input terminal of the first electric cylinder (8) is connected to the signal output terminal of the CPU.

4. The online detection device for pulverized coal particle size in blast furnace according to claim 3, characterized in that: The first weighing mechanism includes four weighing components (9), which are respectively located at the four corners of the bottom of the inner wall of the square frame (6). A screen (7) is set on the four weighing components (9), and the outer wall of the screen (7) is in contact with the inner wall of the square frame (6). The weighing component (9) includes a fixed block and a first weighing device. The fixed block is located at the bottom corner of the inner wall of the square frame (6) and has a hollow structure inside. The first weighing device is located inside the fixed block. A through hole is provided at the top of the fixed block. A support rod passes through the through hole at the top of the fixed block and is connected to the bottom corner of the screen (7). The bottom end of the support rod is connected to the top of the first weighing device. The signal output terminal of the first weighing device is connected to the signal input terminal of the CPU.

5. The online detection device for particle size of pulverized coal injection in blast furnaces according to claim 4, characterized in that: The post-screening powder weighing mechanism includes a second weighing mechanism (14), a bottom slide plate (15), a first side plate (16), a second side plate (17), and a second electric cylinder (18); the second electric cylinder (18) is disposed on the outer wall of the first vertical plate (2), and its piston rod passes through a perforation on the side wall of the first vertical plate (2). The end of the piston rod of the second electric cylinder (18) is connected to the first side plate (16), and the first side plate (16) is located in the screening chamber; the bottom slide plate (15) is located at the bottom end of the first side plate (16) and the second side plate (17). Between the bottom ends of the plate (17); the length of the bottom plate (15) is equal to the distance between the first vertical plate (2) and the third vertical plate (4); the top surfaces of the first side plate (16) and the second side plate (17) are flush with the bottom surface of the third vertical plate (4); the second weighing mechanism (14) is set on the bottom plate (15); the bottom end of the side wall of the second side plate (17) is provided with a strip hole, and the inner walls of the strip hole are provided with a rotating shaft on both sides, and the flip plate is set on the rotating shaft, and the flip plate covers the strip hole of the second side plate (17).

6. The online detection device for pulverized coal particle size in blast furnace according to claim 5, characterized in that: The second weighing mechanism (14) includes a weighing plate and a second weigher; the top surface of the bottom slide plate (15) is provided with a square hole, and the second weigher is provided on the bottom surface of the square hole. The weighing plate is provided on each of the second weighers, and the outer wall of the weighing plate is in contact with the inner wall of the square hole of the bottom slide plate (15); the signal output terminal of the second weigher is connected to the signal input terminal of the CPU.

7. The online detection device for pulverized coal particle size in blast furnace according to claim 6, characterized in that: The powder discharging mechanism includes a high-pressure nitrogen source, a first solenoid valve (19), a duck-shaped nozzle (20), a powder discharging hopper (21), a powder discharging pipe (22), a second solenoid valve, and a first one-way valve; the bottom end of the seventh vertical plate (12) is provided with a strip-shaped hole, the duck-shaped nozzle (20) is provided on the outer wall of the seventh vertical plate (12), and its end is connected to the strip-shaped hole of the seventh vertical plate (12), the other end of the duck-shaped nozzle (20) is connected to the first solenoid valve (19), and the first solenoid valve (19) is connected to the high-pressure nitrogen source through a pipe; the strip-shaped hole at the bottom end of the seventh vertical plate (12) is connected to the second side plate. The strip holes of (17) are aligned in the horizontal direction; the end with the largest opening of the powder discharge hopper (21) is set on the top surface of the third vertical plate (4), the fifth vertical plate (10), the sixth vertical plate (11) and the seventh vertical plate (12); the end with the smallest opening of the powder discharge hopper (21) is connected to the bottom end of the powder discharge pipe (22), and the other end of the powder discharge pipe (22) is connected to the coal powder outlet pipe of the vertical mill; a second solenoid valve and a first check valve are provided on the powder discharge pipe (22); the signal input terminals of the first solenoid valve (19) and the second solenoid valve are connected to the signal output terminal of the CPU.

8. The online detection device for particle size of pulverized coal injection in blast furnaces according to claim 7, characterized in that: The powder feeding mechanism includes a top cover plate (23), a powder feeding pipe (13), a third solenoid valve, and a second check valve; the top cover plate (23) is located at the top of the assembly of the first vertical plate (2), the second vertical plate (3), the third vertical plate (4), and the fourth vertical plate (5); the powder feeding pipe (13) is located on the top cover plate (23), and its bottom end extends into the screening chamber; the top end of the powder feeding pipe (13) is connected to the coal powder outlet pipe of the vertical mill; the third solenoid valve and the second check valve are both located on the powder feeding pipe (13); the signal input end of the third solenoid valve is connected to the signal output end of the CPU.

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