Online pulverized coal fineness detection equipment

Abstract

The invention discloses an online pulverized coal fineness detection device. The problems that manual detection procedures are tedious, detection time is long, the data size is small, and automatic detection precision is low in pulverized coal fineness detection are solved. The screening device comprises an upper cover assembly and a movable lower cover, and the upper cover assembly and a screening net form a sealing cavity; the negative pressure fan forms a negative pressure environment in the sealing cavity, and cooperates with the rotary air knife to enable the pulverized coal to be in a fluidized state, and fine pulverized coal is screened; the weighing device is connected with the screening net through a connecting rod, the upper cover assembly and the movable lower cover are separated from the screening net during weighing, and the weight of pulverized coal before and after screening is obtained respectively; and the control module calculates the fineness of the pulverized coal according to the pulverized coal weight before and after screening. Through the principle of aerodynamic force negative pressure method separation, in combination with high-precision weighing and online pulverized coal fineness calculation, reliable, timely and massive data support is provided for pulverized coal fineness control of an outlet of a coal mill, the carbon content of fly ash after combustion is reduced, and the combustion efficiency of a boiler is improved.

Description

Technical Field

[0001] This invention relates to the field of coal powder fineness detection, and more particularly to an online coal powder fineness detection device. Background Technology

[0002] my country's power production is currently dominated by coal-fired power generation, which accounts for more than 70% of the country's total power generation. Coal-fired power generation will remain the main source of power generation in my country for a considerable period of time.

[0003] The production process of a coal-fired power unit involves burning coal in a boiler to produce high-temperature, high-pressure steam, which drives a steam turbine to rotate and generate electricity, thus converting primary energy into electrical energy.

[0004] The coal used for boiler combustion needs to be ground into fine pulverized coal by a coal mill, and then injected into the boiler for combustion after being mixed with air. The fineness of the pulverized coal entering the boiler directly affects the combustion stability and efficiency of the boiler. Therefore, the measurement and control of the fineness of the pulverized coal produced by the boiler coal mill is extremely important.

[0005] Currently, coal-fired power plants generally use manual analysis to obtain pulverized coal fineness. The measurement method involves manually weighing the powder sample, placing it in a sieve, and then mechanically rotating and striking the sieve. After sieving, coarse powder needs to be manually collected, weighed, and the fineness calculated. This process is cumbersome, time-consuming, and yields limited data, serving only as interim data verification and failing to provide reliable data support for pulverizer fineness control in continuous production. Manual analysis is labor-intensive, time-consuming, and produces very little data. It also fails to achieve closed-loop control of pulverized coal fineness, leading to significant fluctuations in fineness and severely impacting boiler stability and efficiency.

[0006] Currently, no fully automated product for detecting the fineness of pulverized coal has been found for coal-fired power plants. Although there have been reports of methods such as charge method, laser method, photographic comparison method, and micro-nano wave method, the results have been unsatisfactory, and there are no mature products on the market. Summary of the Invention

[0007] This invention primarily addresses the problems of cumbersome manual coal powder fineness detection procedures, long detection times, limited data volume, and low accuracy of automatic detection in existing technologies. It provides an online coal powder fineness detection device that can be installed online and periodically detects coal powder fineness data. This device provides reliable, timely, and abundant data support for controlling the fineness of coal powder at the coal mill outlet, ensuring that the coal powder fineness meets the economical fineness requirements for boiler combustion, reducing the carbon content of fly ash after combustion, improving boiler combustion efficiency, and making a significant contribution to energy conservation and emission reduction in my country.

[0008] The above-mentioned technical problems of the present invention are mainly solved by the following technical solutions:

[0009] An online coal powder fineness detection device includes:

[0010] The sampling device collects the air-coal mixture in the coal powder pipe through a sampler, and after separation, quantitatively feeds the coal powder to the screening device;

[0011] The screening device includes an upper cover assembly that forms a sealed cavity with the screening screen and a movable lower cover; a negative pressure fan creates a negative pressure environment inside the sealed cavity, which, together with a rotating air knife, keeps the coal powder in a fluidized state and screens the fine coal powder.

[0012] The weighing device is connected to the screening screen via a connecting rod. During weighing, the upper cover assembly and the movable lower cover are separated from the screening screen to obtain the weight of coal powder before and after screening.

[0013] The control module controls the operation of the fineness detection equipment and calculates the fineness of the coal powder based on the weight of the coal powder before and after screening.

[0014] By utilizing the principle of pneumatic negative pressure separation combined with high-precision weighing, the fineness of pulverized coal is calculated online, providing reliable, timely, and abundant data support for the control of pulverized coal fineness at the coal mill outlet. This ensures that the fineness of the pulverized coal meets the economic fineness requirements of boiler combustion, reduces the carbon content of fly ash after combustion, and improves boiler combustion efficiency.

[0015] Preferably, the sampling device includes:

[0016] The sampler, including a sampling rod, extends into the pulverized coal pipe during operation to draw in the air-powder mixture;

[0017] The separator separates the air-powder mixture by cyclone separation. The pulverized coal falls into the pulverizer, while the air passes through the upper part of the separator and is blown back into the pulverized coal pipe by a negative pressure fan.

[0018] The powder discharge valve is installed on the powder discharge pipeline to isolate the separator from the powder feeder;

[0019] The coal feeder feeds pulverized coal into the screening device in a metered manner through the feeding pipeline.

[0020] The pulverized coal in the separator falls into the pulverizer through the pulverizer's feed pipe, and then quantitatively and evenly falls into the screening device through the feed pipe located at the bottom of the pulverizer. The feed pipe is located at the bottom of the pulverizer, and there are stirring rods along the radius inside the pulverizer to agitate the pulverized coal. The stirring blades are driven by a motor.

[0021] Preferably, a powder feeding vibrator is installed on the separator; a powder feeding vibrator is installed on the side of the powder feeding pipe near the powder feeder.

[0022] The powder feeding vibrator provides vibration at the separator, which is beneficial for powder feeding; similarly, the powder supply vibrator provides vibration at the powder supply pipeline, which is beneficial for powder supply.

[0023] Preferably, the screening device includes:

[0024] Screening mesh is used to filter coal powder according to its size.

[0025] The upper cover assembly includes an upper cover and a sealing ring, wherein the upper cover is sealed and disposed on the upper part of the screening screen by the sealing ring;

[0026] The lower cover is moved, and the seal is located at the bottom of the sieve screen.

[0027] The upper push rod connects to the sealing ring at the upper cover and drives the sealing ring to move.

[0028] The push rod is connected to the movable lower cover and drives the movable lower cover to move.

[0029] The rotating air knife, installed on the movable lower cover, generates upward rotating airflow, keeping the pulverized coal in a fluidized state.

[0030] During weighing, the upper and lower push rods control the sealing ring at the upper cover and the movable lower cover to detach from the screening screen, ensuring that only the screening screen is connected to the weighing device, thus reducing the influence of other components on the weighing process. In the screening state, the upper cover, sealing ring, and movable lower cover together with the screening screen form a sealed cavity. A negative pressure fan draws this cavity into a negative pressure state, and combined with the rotating air from the rotary air knife, the pulverized coal is fluidized. At this point, the fine powder passes through the screening screen for filtration.

[0031] As a preferred option, the following are also provided:

[0032] The cleaning circuit of the sieve separator sends compressed air into the sieve device from the top cover through the cleaning pipe, and a cleaning valve is installed on the cleaning pipe.

[0033] Compressed air is used to purge the separator to ensure it is clean.

[0034] As a preferred option, it also includes:

[0035] The coarse powder return circuit includes a coarse powder return pipe connecting the top cover and the negative pressure fan, and a coarse powder cleaning valve is installed on the coarse powder return pipe.

[0036] The fine powder return circuit is divided into a fine powder return pipe that connects the movable lower cover and the negative pressure fan, and a fine powder sieving valve is installed on the fine powder return pipe.

[0037] Preferably, the fine powder return pipe is a spiral flexible tube, used to absorb the vertical displacement of the lower sealing cap.

[0038] It facilitates the movement of the lower cover, reducing the impact of movement on system stability.

[0039] Preferably, the weighing device includes:

[0040] An electronic balance is used to weigh the coal powder before and after sieving on a screening screen.

[0041] Adjustment block automatically adjusts the position of the screening assembly;

[0042] Balance block, used to balance the weight of the screening assembly;

[0043] A sealing cover keeps the electronic balance in a sealed environment.

[0044] A sealing ring is used for dustproof sealing of electronic balances. The space between the connecting rod and the sealing cover is sealed with a sealing ring. The sealing ring is closed during weighing to ensure the accuracy of the electronic balance.

[0045] Preferably, the sealing ring is connected to an electronic balance cleaning pipe, and the electronic balance cleaning pipe is equipped with an electronic balance cleaning valve. This ensures dustproof sealing and accurate weighing.

[0046] Preferably, the system also includes a powder feeder cleaning pipe, one end of which is connected to the powder feeder and the other end to compressed air. A powder feeder cleaning valve is installed on the powder feeder cleaning pipe. The separator cleaning can be performed synchronously.

[0047] Preferably, the sampling machine includes:

[0048] The electric push rod drives the inner tube sleeve to reciprocate.

[0049] The outer tube is fixedly inserted into the pulverized coal pipe at one end, and has a pulverized coal inlet facing the direction of pulverized coal entry.

[0050] The inner sleeve is inserted into the outer sleeve and reciprocates within the outer sleeve to collect pulverized coal.

[0051] The sampling rod consists of a nested outer tube and an inner tube, which extends into the pulverized coal pipe during operation to draw in the air-pulverized coal mixture.

[0052] The beneficial effects of this invention are:

[0053] By utilizing the principle of pneumatic negative pressure separation combined with high-precision weighing, the fineness of pulverized coal is calculated online, providing reliable, timely, and abundant data support for the control of pulverized coal fineness at the coal mill outlet. This ensures that the fineness of the pulverized coal meets the economic fineness requirements of boiler combustion, reduces the carbon content of fly ash after combustion, and improves boiler combustion efficiency. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the coal powder fineness detection device and the sieving device when closed.

[0055] Figure 2 This is a schematic diagram of the structure of the coal powder fineness detection device and the screening device of the present invention when the device is opened.

[0056] Figure 3This is a schematic diagram of the sampling mechanism of the present invention.

[0057] Figure 4 This is a module connection diagram of the control module of the present invention.

[0058] In the diagram: 1. Sampler, 2. Separator, 3. Powder feeder, 4. Screening screen, 5. Electronic balance, 6. Negative pressure fan, 7. Powdered coal pipe, 8. Powder inlet valve of the screener, 9. Upper cover, 10. Movable lower cover, 11. Upper push rod, 12. Lower push rod, 13. Rotary air knife, 14. Air knife motor, 15. Connecting rod, 16. Adjusting block, 17. Balance block, 18. Sealing cover, 19. Sealing air ring, 20. Powder discharge valve, 21. Powder discharge vibrator, 22. Powder feeding vibrator 23. Cleaning valve, 24. Push rod air inlet control valve, 25. Electronic balance cleaning valve, 26. Coarse powder cleaning valve, 27. Fine powder sieving valve, 28. Powder feeder and separator cleaning valve, 29. Manual sampling port, 30. Control unit, 31. Solenoid valve, 32. Sealing ring, 33. Sampling inlet pneumatic valve, 34. Sampling separation regulating valve, 35. Electric push rod, 36. Outer sleeve, 37. Inner sleeve, 38. First sealing device, 39. Second sealing device. Detailed Implementation

[0059] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0060] Example:

[0061] This embodiment provides an online coal powder fineness detection device, such as... Figure 1 and Figure 2 As shown, it includes a sampler 1, a separator 2, a powder feeder 3, a screening device, a weighing device, a negative pressure fan 6, and a coal powder pipe 7.

[0062] Sampling machine 1 collects coal powder samples from the coal powder pipe 7. The specific structure of sampling machine 1 is as follows: Figure 3 As shown, the sampler 1 includes an electric push rod 35, an outer sleeve 36, an inner sleeve 37, and a sealing device. One end of the outer sleeve 36 is fixedly inserted into the pulverized coal pipe 7, and a pulverized coal inlet is provided on the outer sleeve 36 in the pulverized coal pipe 7 facing the pulverized coal inlet direction. The inner sleeve 37 is inserted into the outer sleeve 36, and the electric push rod 35 drives the inner sleeve 37 to reciprocate within the outer sleeve 36 to ensure representative sampling.

[0063] The sealing device includes a first sealing device 38 and a second sealing device 39. The first sealing device 38 is located at the connection between the outer sleeve 36 and the inner sleeve 37; the second sealing device 39 is located at the connection between the outer sleeve 36 and the pulverized coal pipe 7. The nested outer sleeve and inner sleeve act as a sampling rod, which extends into the pulverized coal pipe during operation to draw in the air-powder mixture.

[0064] The separator 2 has a coal powder inlet pipe connected to the coal powder pipe 7 on its side. The sampler 1 is installed on the coal powder inlet pipe. A sampling inlet pneumatic valve 33 is installed between the sampler 1 and the separator 2. A return air pipe connected to the negative pressure fan 6 is installed on the upper part of the separator 2. A sampling separation regulating valve 34 is installed on the return air pipe between the separator 2 and the negative pressure fan 6.

[0065] Separator 2 separates the air-powder mixture by cyclone separation. The coal powder falls into the coal feeder 3, while the air passes through the upper part of separator 2 and is blown back into the coal powder pipe 7 by negative pressure fan 6.

[0066] A powder feeding pipe is installed below the separator 2, and the other end of the powder feeding pipe is connected to the powder feeder 3 from above. A powder feeding vibrator 21 is installed on the separator 2, and a powder feeding valve 20 is installed on the powder feeding pipe to separate the separator 2 and the powder feeder 3.

[0067] The sampler 1 collects the air-coal mixture in the coal powder pipe through the sampling rod. The separator 2 separates the air-coal mixture by cyclone separation. The coal powder falls into the feeder 3. The coal powder in the separator is controlled by the coal powder discharge valve 20 to control whether the coal powder in the separator falls into the feeder 3. The coal powder discharge vibrator 21 provides vibration at a fixed frequency, which is conducive to the falling of coal powder in the separator 2.

[0068] A pulverizing pipe is installed at the bottom of the pulverizing feeder 3, and the other end of the pulverizing pipe is connected to the screening device through the upper cover 9. Inside the pulverizing feeder 3, stirring blades are arranged along the radius to agitate the pulverized coal, and the stirring blades are driven by a motor. A manual sampling port 29 is also provided at the bottom of the pulverizing feeder 3.

[0069] The motor drives the stirring blades to rotate, stirring the coal powder in the feeder 3, so that the coal powder can fall evenly into the screening device through the feeding pipe.

[0070] A sieve inlet valve 8 is installed on the powder feeding pipe, and a powder feeding vibrator 22 is installed on the side of the powder feeding pipe near the powder feeder 3.

[0071] By controlling the opening of the pulverized coal inlet valve 8 of the sieve, the amount of pulverized coal falling into the sieve device can be controlled; the pulverized coal vibrator 22 provides vibration on the pulverized coal inlet pipe, which is beneficial to the falling of pulverized coal.

[0072] The screening device includes a screening screen 4, an upper cover assembly, a movable lower cover 10, and a rotating air knife 13. The upper cover assembly includes an upper cover 9 and a sealing ring 32.

[0073] The upper cover 9 is sealed to the top of the sieve 4 via a sealing ring 32; the movable lower cover 10 is sealed to the bottom of the sieve via a sealing structure. The upper cover 9 and the movable lower cover 10 seal with the sieve 4 from the top and bottom respectively, forming a sealed cavity.

[0074] A rotary air knife 13 is installed on the movable lower cover 10 inside the sealed cavity. The movable lower cover 10 also has an air knife motor 14 for driving the rotary air knife 13 and an air inlet. The rotary air knife 13 generates upward rotating air, which fluidizes the coal powder, and the screening screen 4 filters the coal powder according to its size. A coarse powder return circuit and a fine powder return circuit are provided between the screening device and the negative pressure fan 6.

[0075] The coarse powder return circuit includes a coarse powder return pipe connecting the upper cover 9 and the negative pressure fan 6, and a coarse powder cleaning valve 26 is installed on the coarse powder return pipe. The fine powder return circuit includes a fine powder return pipe connecting the movable lower cover 10 and the negative pressure fan 6, and a fine powder screening valve 27 is installed on the fine powder return pipe.

[0076] The sealing ring 32 at the top cover 9 is connected to the upper push rod 11, which drives the sealing ring 32 at the top cover 9 to move up and down. The movable lower cover 10 is connected to the lower push rod 12, which drives the movable lower cover 10 to move up and down. The fine powder return pipe is a spiral flexible tube, which facilitates the movement of the movable lower cover 10 and reduces the impact of movement on the stability of the system.

[0077] The upper and lower push rods are also connected to push rod air inlet pipes. One end of the push rod air inlet pipe is connected to the push rod, and the other end of the push rod air inlet pipe is connected to compressed air. A push rod air inlet control valve 24 is installed on the push rod air inlet pipe.

[0078] During the pulverization and screening process, the upper cover 9 and the movable lower cover 10 are sealed and connected to the screening screen 4 by the upper and lower push rods to form a sealed cavity. The negative pressure fan 6 creates a negative pressure environment in the sealed cavity of the screening device. Combined with the upward rotating air generated by the rotating air knife 13, the pulverized coal is in a fluidized state and screened according to the size of the pulverized coal.

[0079] The weighing device includes a sealing cover 18, an electronic balance 5, a balance block 17, and an adjusting block 16.

[0080] The electronic balance 5 is housed within a sealed cover 18, which has a sealing ring 19. A connecting rod 15 passes through the sealing ring 19, connecting the electronic balance 5 and the sieve 4. The connecting rod 15 transfers the weight of the sieve 4 to the electronic balance 5. An adjusting block 16 automatically adjusts the position of the sieve assembly, and a balance block 17 balances the weight of the sieve assembly. The sealing ring 19 provides dust protection for the electronic balance 5, sealing the space between the connecting rod 15 and the sealed cover 18. The sealing ring 19 is closed during weighing to ensure the accuracy of the electronic balance.

[0081] During weighing, the sealing ring 32 at the upper cover 9 and the lower cover 10 are removed from the sieve 4 by the upper and lower push rods respectively. The weighing device only weighs the weight of the sieve 4 and weighs the weight before and after sieving to calculate the fineness of the coal powder.

[0082] The system in this embodiment also includes a cleaning device. The cleaning device includes a screen cleaning circuit, an electronic balance cleaning circuit, and a powder feeder and separator cleaning circuit.

[0083] The cleaning circuit of the sieve divider sends compressed air into the sieve device from the upper cover 9 through the cleaning pipe, and the cleaning pipe is equipped with a cleaning valve 23.

[0084] The electronic balance cleaning circuit sends compressed air through the electronic balance cleaning pipe from the sealing air ring 19, and the electronic balance cleaning pipe is equipped with an electronic balance cleaning valve 25.

[0085] The powder feeder and separator cleaning circuit delivers compressed air to powder feeder 3 and separator 2 respectively through the powder feeder and separator cleaning pipes. Powder feeder and separator cleaning valves 28 are installed on the powder feeder and separator cleaning pipes. Separator cleaning is connected to powder feeder cleaning, allowing for simultaneous cleaning.

[0086] When cleaning the pulverizer 3 and separator 2, close the pulverizer discharge valve 2 and open the pulverizer and separator 2 cleaning valve 28. Compressed air is sent into the pulverizer 3 and separator 2 respectively through the parallel pulverizer and separator cleaning circuit to clean the residual coal powder in the pulverizer 3 and separator 2.

[0087] When cleaning the weighing device, open the electronic balance cleaning valve 25 and send compressed air through the electronic balance cleaning circuit to the sealing air ring 19. This can remove a small amount of coal dust from the sealing air ring 19 and further prevent coal dust or dust from entering the sealing cover of the weighing device.

[0088] When cleaning the screener, open the cleaning valve 23; at the same time, close the screener inlet valve 8 to isolate the feeder 3 and the screening device. Compressed air is then introduced into the screening device through the cleaning circuit to clean the coal powder within the screening device.

[0089] The online coal powder fineness detection device in this embodiment achieves its function by using the principle of pneumatic negative pressure separation combined with high-precision weighing and cleaning.

[0090] The online coal powder fineness detection device in this embodiment also includes a control module, such as... Figure 4 As shown, the control module includes a control unit 30. The control unit 30 can be a semiconductor chip (industrial control computer) or a PLC. The control unit 30 is connected to several solenoid valves 31 (including electric actuators, contactors, etc.) through I / O ports. In this embodiment, the solenoid valves 31 include a sieve feed valve 8, a feed valve 20, an upper cleaning valve 23, a lower cleaning valve 24, an electronic balance cleaning valve 25, a coarse powder cleaning valve 26, a fine powder sieve valve 27, and a feeder cleaning valve 28; different solenoid valves 31 are controlled to switch on and off at different stages according to the built-in program.

[0091] The control unit 30 is also connected to a motor to drive the motor to rotate. In this embodiment, the motor includes an air knife motor 14 and a negative pressure fan 6.

[0092] The control unit 30 is also connected to an upper push rod 11 and a lower push rod 12, which drive the upper and lower push rods to move up and down.

[0093] The control unit 30 is also connected to the electronic balance 5 to receive the mass of coal powder before and after sieving by the electronic balance 5 and to perform calculations.

[0094] Furthermore, the control unit 30 can also be connected to a human-machine interface module to display the equipment's operating status and weight calculation results, and to interact with relevant personnel for control. The control unit 30 is communicatively connected to the sampler 1, controlling the sampler 1 to sample the coal powder from the system.

[0095] The specific working process of this device is as follows:

[0096] 1) Pulverized coal sampling and pulverized coal feeding into the pulverizer:

[0097] Status: Machine system cleaning complete. Coarse powder cleaning valve 26 and fine powder screening valve 27 are closed; sampling separation regulating valve 34 is open.

[0098] Sampling action: The negative pressure fan 6 is turned on. After 1 second, the fan outlet pipe purging is automatically turned off, the sampling tube purging is turned off, and the sampler 1 is turned on. The extension and retraction of the inner sleeve is controlled by the electric push rod 35 (the sampling rod extends into the coal powder pipe at a constant speed, and withdraws at the same speed when the stroke is completed. It can be set to extend and withdraw N times to ensure the sampling volume).

[0099] After the last sampling rod returns to its original position, the electric push rod 35 closes, simultaneously shutting down the negative pressure fan 6, the sampling inlet pneumatic valve 33, and the sampling separation regulating valve 34. Sampling ends 1 second later.

[0100] While sampling, the powder feeder 3 will feed powder by gravity. After sampling is completed, it will stand still for 10 seconds, then the powder feeding vibrator 21 will be turned on, and after 10 seconds, the powder feeding will end.

[0101] 2) Powder feeding into the screening device:

[0102] The sieving device has been cleaned. The lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to loosen the sieve screen 4. After the weighing device is zeroed (the weight G0 is recorded), the powder can be discharged.

[0103] The lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to press the screen 4. The screener powder inlet valve 8 is opened (after it is in position), the powder feeding vibrator 22 is opened, and the powder feeder 3 is opened (the powder feeding amount is controlled at 25-30g according to the time setting). Then, the powder feeder 3, the screener powder inlet valve 8, and the powder vibrator 22 are closed. (The control of the second powder feeding time needs to be calculated).

[0104] 3) Weighing the sample powder:

[0105] After 10 seconds of stillness, the lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to loosen the sieve screen 4. After 10 seconds, read the reading of the weighing device (if the reading is less than 20g, feed powder again and weigh it again until the sample powder is around 30g). Record the weight G1. The weight is related to the fine powder sieving program (the formula "G1X coefficient" determines the system sieving time).

[0106] 4) Fine powder sieving:

[0107] The lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to press the screen 4. The fine powder screening valve 27 is opened, and the coarse powder cleaning valve 26 is closed. After it is in place, the air knife motor 14 is turned on, and the negative pressure fan 6 is turned on (1 second can be set). After 5 seconds, the solenoid valve of the screener is turned on and blown for 5 seconds before being turned off. After the system screens for 240 seconds (related to weight, the time of the whole step), 16 / 17 / 12 are turned off and left to stand for 10 seconds.

[0108] 5) Weighing the coarse powder:

[0109] The lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to loosen the sieve screen 4. After 10 seconds, the reading of the weighing device is read and recorded as G2.

[0110] 6) Calculate the fineness:

[0111] R = (G2-G0) / (G1-G0)*100% (Generally, G0 is zero after being zeroed out, but each GO before being zeroed out needs to be accumulated. When ΣG0≥10g, manual cleaning is required).

[0112] 7) Fineness accuracy analysis:

[0113] If R is within the normal range (e.g., 10-35%), perform system cleaning; otherwise, only clean the screener and repeat steps 2) to 6). (If R is less than 10% twice consecutively, the system will stop and an alarm will sound: please check the screen. If R is less than 35%, a negative pressure alarm will sound and the machine will stop: check the screener's sealing ring.)

[0114] 8) Screening device cleaning:

[0115] Close the fine powder screening valve 27 and open the coarse powder cleaning valve 26. After the valves are in position, turn on the negative pressure fan 6 / air knife motor 14 and clean for 150 seconds. Then open the upper cleaning valve 23 and the lower cleaning valve 24. After 30 seconds, close the upper cleaning valve 23 and the lower cleaning valve 24. Clean for another 30 seconds and then turn off the negative pressure fan 6 / air knife motor 14. After standing still for 10 seconds, the lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to loosen the screening screen 4. After 10 seconds, read the weighing device reading G0. If G0 ≥ 3g, repeat the first part of step 8. Finally, record the weighing reading and accumulate it in the powder accumulation ΣG0 (the system needs to be zeroed after cleaning). After cleaning the sieve, the fineness of the sample powder can be measured again. If the deviation from ΣG0 is too large (e.g., 10g), a fault can be reported.

[0116] 9) System cleaning:

[0117] When the measurement fineness is within the normal range, the system can be cleaned directly;

[0118] The lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to press the sieve screen 4. The sampling inlet pneumatic valve 33, the sampling separation regulating valve 34 and the fine powder sieve valve 27 are closed. After the sieve inlet valve 8 and the coarse powder cleaning valve 26 are in place, the negative pressure fan 6 and the air knife motor 14 are turned on. After 1 second, the powder-feeding vibrator 22 is turned on (vibrate for 5 seconds, then close the fine powder sieve valve 27 and vibrate again). After 3 seconds, the powder feeder 3 and the powder feeder cleaning valve 28 are turned on. After running for 120 seconds, the powder-feeding vibrator 22 / powder feeder 3 / powder feeder cleaning valve 28 are turned off. The upper cleaning valve 23 and the lower cleaning valve 24 are turned on. After running for another 60 seconds, the upper cleaning valve 23 and the lower cleaning valve 24 are turned off. The cleaning is stopped (the negative pressure fan 6 and the air knife motor 14 are turned off). After standing still for 10 seconds, the weighing device reading G0 is read. If G0 ≥ 3g, the cleaning is repeated in step 9.

[0119] 10) After the system is cleaned, the next measurement cycle can be executed.

[0120] 11) Chassis cleaning:

[0121] After the system has run 10 times (configurable), perform a chassis cleaning after the system cleaning is complete.

[0122] The lower push rod 12 drives the lower cover 10 to move, and the upper push rod 11 drives the sealing ring 32 to loosen the sieve screen 4. The coarse powder cleaning valve 26 is opened, and the fine powder sieve valve / 2 is in place. The negative pressure fan 6 is started, and the chassis purging solenoid valve is opened. Cleaning lasts for 10 minutes (adjustable). The negative pressure fan 6 is then stopped. After 10 seconds of stillness, the reading Gq of the weighing device is recorded.

[0123] If Gq > 3, execute program 9; if Gq < 0, subtract it from the accumulated powder weight ΣG0. The measurement cycle can be resumed after cleaning is completed.

[0124] It should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. An on-line coal fineness detection apparatus, characterized by, include: The sampling device collects the air-coal mixture in the coal powder pipe (7) through the sampler (1), and after separation, the coal powder is quantitatively fed to the screening device; The screening device includes an upper cover assembly that forms a sealed cavity with the screening screen (4) and a movable lower cover (10); the negative pressure fan (6) creates a negative pressure environment in the sealed cavity, and the rotating air knife (14) keeps the coal powder in a fluidized state to screen the fine coal powder. The weighing device is connected to the sieve (4) via a connecting rod (15). During weighing, the upper cover assembly and the movable lower cover (10) are separated from the sieve (4) to obtain the weight of coal powder before and after sieving. The control module controls the operation of the fineness detection equipment and calculates the fineness of the coal powder based on the weight of the coal powder before and after screening.

2. The online coal fineness detection device according to claim 1, characterized in that, The sampling device includes: The sampler (1) includes a sampling rod that extends into the coal powder pipe (7) during operation to draw in the air-coal mixture; The separator (2) separates the air-powder mixture by cyclone separation. The coal powder falls into the coal feeder (3), and the air is blown back into the coal powder pipe (7) through the upper part of the separator by the negative pressure fan (6). The powder discharge valve (20) is installed on the powder discharge pipeline to isolate the separator (2) from the powder feeder (3); The coal feeder (3) feeds coal powder quantitatively to the screening device through the coal feeding pipe.

3. The online coal powder fineness detection device according to claim 2, characterized in that, A powder feeding vibrator (21) is installed on the separator (2); a powder feeding vibrator (22) is installed on the side of the powder feeding pipe near the powder feeder (3).

4. An online coal powder fineness detection device according to claim 1, 2, or 3, characterized in that, The screening device includes: Screening mesh (4) is used to screen and filter coal powder according to its size; The upper cover assembly includes an upper cover (9) and a sealing ring (32), wherein the upper cover (9) is sealed on the upper part of the sieve (4) by the sealing ring (32); Move the lower cover (10) and seal it at the bottom of the sieve (4); The upper push rod (11) is connected to the sealing ring (32) at the upper cover (9) and drives the sealing ring (32) to move; The lower push rod (12) is connected to the movable lower cover (10) and drives the movable lower cover (10) to move; The rotating air knife (13) is set on the movable lower cover (10) to generate upward rotating air and fluidize the coal powder.

5. The online coal powder fineness detection device according to claim 4, characterized in that, It also includes: The cleaning circuit of the sieve is used to send compressed air into the sieve device from the top cover (9) through the cleaning pipe. A cleaning valve (23) is installed on the cleaning pipe.

6. The online coal powder fineness detection device according to claim 4, characterized in that, Also includes: The coarse powder return circuit includes a coarse powder return pipe connecting the top cover (9) and the negative pressure fan (6), and a coarse powder cleaning valve (26) is installed on the coarse powder return pipe; The fine powder return circuit includes a fine powder return pipe connecting the movable lower cover (10) and the negative pressure fan (6), and a fine powder screening valve (27) is installed on the fine powder return pipe.

7. The online coal powder fineness detection device according to claim 6, characterized in that, The fine powder return pipe is a spiral flexible tube that absorbs the vertical displacement of the lower cover (10).

8. An online coal powder fineness detection device according to claim 1, 5, 6, or 7, characterized in that, The weighing device includes: Electronic balance (5) is used to weigh the coal powder before and after sieving on the sieve (4); Adjusting block (16) automatically adjusts the position of the screening assembly; Balance block (17) balances the weight of the screening assembly; The sealing cover (18) places the electronic balance (5) in a sealed environment; A sealing ring (19) is used for dustproof sealing of the electronic balance (5). It is located between the connecting rod (15) and the sealing cover (18) and closes the sealing ring (19) when weighing.

9. The online coal powder fineness detection device according to claim 8, characterized in that, The sealing ring (19) is connected to an electronic balance cleaning pipe, and an electronic balance cleaning valve (25) is installed on the electronic balance cleaning pipe.

10. The online coal powder fineness detection device according to claim 1, characterized in that, The sampling machine (1) includes: The electric push rod (35) drives the inner tube sleeve (37) to reciprocate; The outer sleeve (36) is fixedly inserted into the pulverized coal pipe (7) at one end, and has a pulverized coal inlet facing the pulverized coal inlet direction; The inner sleeve (37) is inserted into the outer sleeve (36) and reciprocates within the outer sleeve (36) to collect coal dust.

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