A uniform thickness screen for pulverized coal injection and its use method

Abstract

The present invention proposes a uniform thickness screen for pulverized coal injection and a method for using the same, which solves the problem of excessive slime in the material mixed on the screen after desliming the raw coal. The uniform thickness screen includes a screen box body, a vibrator is provided on the screen box body, a multi-angle screening assembly is provided in the screen box body, a scrubbing assembly is fixed on the upper side of the middle part of the screening assembly, the scrubbing assembly includes a transverse conical mesh frame, the conical mesh frame is filled with polyurethane scrubbing rods, a flushing assembly is provided above the discharge side of the conical mesh frame, and the flushing direction of the flushing assembly is opposite to the movement direction of the coal material; a feed chute is provided at the feed end of the screening assembly, a stirring assembly is provided in the feed chute, and the stirring assembly is connected to the screen box body through the feed chute. The present invention improves the desliming effect, shortens the desliming path, and reduces the amount of flushing water used in the desliming process.

Description

Technical Field

[0001] The present invention relates to the technical field of uniform thickness screens, in particular to a uniform thickness screen for pulverized coal injection and a method for using the screen. Background Art

[0002] PCI coal sorting typically utilizes a pre-desliming process followed by a pressurized three-product dense medium cyclone. The raw coal is crushed to less than 50mm. The 50-0mm raw coal is deslimed to 1mm using a uniform thickness screen, resulting in undersize coarse coal slime and oversize 50-1mm mixed raw coal. The oversize mixed coal is sorted using a pressurized three-product dense medium cyclone. The undersize coarse coal slime is classified using a hydraulic classifying cyclone. The underflow is a coarse coal slime of 1-0.25mm, and the overflow is a fine coal slime of 0.25-0mm. These are processed in a coarse coal slime separator and a flotation machine, respectively.

[0003] When the existing uniform thickness screen is used for 1mm desliming, there is a problem that the amount of coal slime in the mixed raw coal on the screen is too large and the screening efficiency needs to be improved, which will have the following adverse effects:

[0004] (1) Excessive coal slime enters the heavy medium cyclone along with the mixed raw coal, which will increase the coal slime content in the heavy medium suspension, destroy the stability of the suspension, and make the density control of the suspension more complicated and more difficult to adjust;

[0005] (2) Coal slime will reduce the density of the suspension, reduce the separation density of the heavy medium cyclone, increase the mismatch of clean coal in the coal and the mismatch of medium coal in the gangue, resulting in a decrease in the yield of clean coal and medium coal;

[0006] (3) The increase in the amount of coal slime brought in will reduce the removal efficiency of clean coal, medium coal and gangue, increase the medium consumption, and in the subsequent magnetic separation stage, excessive coal slime will also reduce the magnetic separation efficiency and increase the magnetic separation cost.

[0007] In addition, before the 50~0mm raw coal enters the equal-thickness screen, the raw coal and water are mixed in the feed chute mainly through the impact force of the water flow, while preventing the material from sinking to the bottom. Due to space limitations in the feed chute and the control of equipment costs and production costs, it is not suitable to increase mechanical stirring, and it mainly relies on the huge impact force of the water flow.

[0008] The 50~0mm raw coal is vibrated and deslimed on the equal-thickness screen. The large-particle coal moves upward, the fine-particle coal moves downward, and the coal with a particle size of less than 1mm passes through the screen. In the middle and late stages of desliming of the coal on the screen (desliming is mainly carried out at this stage), the fine-particle materials adhere to the surface of the large particles, or stick together, or are at the bottom of the material group on the screen, which hinders the contact between the coal with a particle size of less than 1mm and the screen surface. Water flushing from the upper side of the material group on the screen, slowing down the movement of the material group on the screen, and increasing the screening time, the improvement of desliming efficiency is still limited. Summary of the Invention

[0009] The present invention provides a uniform thickness screen for pulverized coal injection and a method for using the same, which improves the desludging effect, shortens the desludging path, and reduces the amount of flushing water used in the desludging process.

[0010] The technical solution of the present invention is implemented as follows: a uniform thickness screen for pulverized coal injection, comprising a screen box body, a vibrator provided on the screen box body, a multi-angle screening assembly provided in the screen box body, a scrubbing assembly fixed on the upper side of the middle part of the screening assembly, the scrubbing assembly comprising a transverse conical mesh frame, the conical mesh frame being filled with polyurethane scrubbing rods, a flushing assembly being provided above the discharge side of the conical mesh frame, the flushing direction of the flushing assembly being opposite to the moving direction of the coal material; a feed chute being provided at the feed end of the screening assembly, a stirring assembly being provided in the feed chute, the stirring assembly being connected to the screen box body through the feed chute.

[0011] Furthermore, the screening assembly includes multiple sections of longitudinal screen bodies with successively decreasing inclination angles. The longitudinal screen body with the smallest inclination angle is the last section of the screen body. A recoil assembly is provided below the middle of the last section of the screen body. The recoil assembly flushes water from the lower side of the last section of the screen body at an angle upward, and the flushing direction is opposite to the movement direction of the coal.

[0012] Furthermore, the feed chute includes a feed section, a premixing section and a discharge section connected in sequence. The feed end of the premixing section is provided with a flushing pipe, and the flushing direction of the flushing pipe is opposite to the movement direction of the raw coal. The discharge end of the premixing section is provided with an overflow baffle. The stirring assembly is located in the premixing section. The stirring assembly is a flat horizontal frame. Connecting rods are fixed at both ends of the stirring assembly. A perforation is provided on the premixing section. The perforation is higher than the overflow baffle. The connecting rod passes through the perforation and is connected to the screen box body. A rubber sealing plug is provided at the perforation.

[0013] Furthermore, the screening assembly includes a polyurethane flexible frame with positioning slots arranged in a horizontal and vertical array. Screen panels are mounted within the slots, and the joints between the upper surfaces of adjacent panels are bonded with waterproof tape. Compared to bulky, integrated screens, this structure facilitates the production, transportation, and on-site assembly of the screening assembly, as well as subsequent replacement of the screen panels.

[0014] Furthermore, support shafts are installed at intervals within the screen box body along the direction of coal conveyance. The height of the support shafts is adjustable and located below the screening assembly to support the assembly. Polyurethane elastic blocks are fixed to both sides of the screen box body along the direction of coal conveyance. The lower ends of the polyurethane elastic blocks seal against the edges of the upper side of the screening assembly. The polyurethane elastic blocks seal and position the upper edge of the screening assembly, preventing unscreened coal slime from passing through the edges of the screening assembly.

[0015] A polyurethane flexible frame allows for flexible connection between adjacent horizontal screen panels. By adjusting the height of the support shafts and the number of support shafts corresponding to each longitudinal screen section, the length and tilt angle of each longitudinal screen section can be adjusted as needed. Existing uniform thickness screens have adjustable angles for each longitudinal screen section, but the length is usually fixed, making it difficult to adjust as needed.

[0016] Furthermore, a screen hopper is provided below the screening assembly, and a fixed shaft is provided at the upper end of the screen hopper, which abuts against the lower side of the screening assembly. When the screening assembly vibrates, it collides with the fixed shaft, causing the material stuck in the screen hole to be released.

[0017] A method for using a uniform thickness screen for pulverized coal injection comprises the following steps:

[0018] (1) The vibrator drives the screen box body and the screening assembly to vibrate, and the screen box body drives the stirring assembly to vibrate in the feed chute, so that the raw coal and water are mixed in the feed chute to form coal slurry;

[0019] (2) The coal slurry enters the screening assembly for desliming, and the oversize material in the middle of the screening assembly enters the conical mesh frame. As the screening assembly vibrates, the polyurethane scrubbing rod scrubs the oversize material, and at the same time, the flushing assembly performs reverse flushing to wipe off the coal slime adhering to the surface of the oversize material particles, making the surface of the oversize material particles smooth;

[0020] (3) The scrubbed material on the screen continues to be desludged along the screening assembly.

[0021] Furthermore, in step (3), the scrubbed oversize material continues to be deslimed along the screening assembly, and after entering the middle of the final screen body, the backflush assembly flushes water from the lower side of the final screen body at an angle upward, and the fine particles of oversize material at the bottom of the upper surface of the final screen body are moved upward by the water impact, so that the particle gaps of the oversize material are opened, and with the subsequent vibration desliming, it is convenient for the coal slime to contact the screen surface through the particle gaps and pass through the screen.

[0022] Furthermore, in step (1), when the raw coal enters the premixing section through the feeding section, the water flushing pipe flushes the raw coal in the reverse direction. With the impact force of the water and the vibration stirring of the stirring assembly, the raw coal and water are mixed to form a coal slurry. The coal slurry overflows into the discharge section through the overflow baffle, and then enters the screening assembly through the discharge section.

[0023] Furthermore, in steps (1) to (3), when the screening assembly vibrates, the lower side of the screening assembly collides and vibrates with the fixed shaft, causing the blocking material to separate from the sieve holes of the screening assembly.

[0024] Beneficial effects of the present invention:

[0025] The present invention adds a scrubbing assembly to the upper middle portion of the screening assembly. During the vibratory desludging of the oversize material, scrubbing is performed simultaneously, breaking up agglomerated coal, scrubbing fine particles adhering to the surfaces of larger particles, removing adhered coal slime, and smoothing the surface, reducing the likelihood of subsequent slime adhesion. Furthermore, the use of a polyurethane scrubbing rod, coordinated with the movement rate of the coal in the middle of the screening assembly, prevents over-abrasion of coal particles during scrubbing while ensuring effective scrubbing.

[0026] The present invention adds a stirring assembly in the feed chute, and the stirring assembly is connected to the screen box body, vibrates with the vibration of the screen box body, and then vibrates and stirs the coal slurry in the feed chute. The stirring assembly is a flat horizontal frame, and stirring is achieved by vibration. The space requirement for the feed chute is small, and no new drive is added. The combination of hydraulic impact and vibration stirring is conducive to achieving rapid mixing of raw coal and water, and reducing the requirement for water impact force.

[0027] The present invention adds a backwash component below the middle of the last stage screen body, which flushes water obliquely from bottom to top to break up the fine particles accumulated at the bottom of the material group, making it easier for the coal slime to contact the screen surface and further facilitate the coal slime to pass through the screen.

[0028] The present invention improves the desludging effect and shortens the screening and desludging path by cooperating with the scrubbing component and the backflushing component; compared with flushing from the upper side of the screen during the desludging process, the present invention is also beneficial to reducing the amount of flushing water used in the desludging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a schematic structural diagram of Example 1 of the present invention;

[0031] Figure 2 Schematic diagram of the internal structure of the screen box body;

[0032] Figure 3 for Figure 2 Schematic diagram of the local structure of A;

[0033] Figure 4 It is a structural diagram of the feeding chute;

[0034] Figure 5 Schematic diagram of the structure of the screening component;

[0035] Figure 6Schematic diagram of the structure of the positioning groove;

[0036] Figure 7 This is a schematic structural diagram of Example 3 of the present invention;

[0037] Figure 8 Schematic diagram of the structure of the polyurethane elastic block;

[0038] Figure 9 Schematic diagram of the structure of the stirring component.

[0039] Screen box body 1, base frame 2, spring seat 3, underscreen hopper 4, vibrator 5, screening assembly 6, scrubbing assembly 7, conical mesh frame 8, polyurethane scrubbing rod 9, flushing assembly 10, feeding section 11, premixing section 12, flushing pipe 13, overflow baffle 14, stirring assembly 15, connecting rod 16, perforation 17, final screen body 18, backflushing assembly 19, polyurethane flexible frame 20, positioning groove 21, screen sheet 22, waterproof tape 23, support shaft 24, strip hole 25, polyurethane elastic block 26, fixed shaft 27, inner vertical section 28, transverse section 29, outer vertical section 30, support rod 31. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] like Figure 1 and 2 As shown, a uniform thickness screen for pulverized coal injection comprises a screen box body 1 and a base frame 2, connected to the base frame 2 via a spring seat 3. A vibrator 5 is mounted on the screen box body 1. A multi-angle screening assembly 6 is longitudinally disposed within the screen box body 1. The vibrator 5 drives the screen box body 1 and screening assembly 6 to vibrate. An undersize hopper 4 is located below the screening assembly 6, into which the undersize material enters.

[0043] like Figure 2 and 3 As shown, a scrubbing assembly 7 is fixed on the upper side of the middle of the screening assembly 6, and the scrubbing assembly 7 vibrates synchronously with the screening assembly 6. The scrubbing assembly 7 includes a transverse conical mesh frame 8, which is fixed on the upper side of the middle of the screening assembly 6. The conical mesh frame 8 is filled with a polyurethane scrubbing rod 9. The diameter of the polyurethane scrubbing rod 9 is larger than the aperture of the conical mesh frame 8, and the polyurethane scrubbing rod 9 cannot be detached from the conical mesh frame 8. The aperture of the conical mesh frame 8 is larger than the particle size of the raw coal, which facilitates the raw coal to pass through the conical mesh frame 8.

[0044] The front end of the screening assembly 6 has a larger inclination angle, so the coal moves faster, while the rear end has a smaller inclination angle, so the coal moves slower. The scrubbing assembly 7 is placed in the middle of the screening assembly 6, so that the coal passes through the conical mesh frame 8 at an appropriate time. This prevents the coal from moving too fast and not being fully scrubbed in time. It also allows the coal to pass through the conical mesh frame 8 at a faster speed, preventing coal from accumulating at the conical mesh frame 8. The use of a polyurethane scrubbing rod and the rapid passage of the coal through the conical mesh frame 8 prevents over-abrasion of the coal particles during scrubbing.

[0045] In addition, the screened material in the middle of the screening component 6 has been preliminarily screened. The large particles are adhered to the surface of the coal slime, or the fine particles of coal slime are agglomerated, which increases the difficulty of subsequent screening. Through the setting of the scrubbing component 7, on the one hand, the agglomerated fine particles of coal slime are broken up, and on the other hand, the surface of the large particles is scrubbed to remove the adhered coal slime and make the surface smooth, thereby reducing the probability of subsequent coal slime adhesion.

[0046] A flushing assembly 10 is fixed above the discharge side of the conical mesh frame 8. The flushing assembly 10 is a row of flushing nozzles arranged horizontally. The flushing direction of the flushing assembly 10 is opposite to the moving direction of the coal material, so that the scrubbed coal slime is fully mixed with water and enters the screen.

[0047] like Figure 1 and 4 As shown, the feed end of the screening assembly 6 is provided with a feed chute, which includes a feed section 11, a premixing section 12, and a discharge section connected in sequence. The opening of the feed section 11 faces upward to facilitate the entry of raw coal, and the opening of the discharge section faces downward and connects to the upper end of the screening assembly 6. A flushing pipe 13 is fixed to the feed end of the premixing section 12. The flushing direction of the flushing pipe 13 is opposite to the movement direction of the raw coal. An overflow baffle 14 is fixed to the discharge end of the premixing section 12. After the raw coal and water are fully mixed, a coal slurry is formed. The coal slurry overflows through the overflow baffle 14 into the discharge section, facilitating the lateral and uniform feeding of the screening assembly 6.

[0048] like Figure 4 and 9As shown, the stirring assembly 15 is located within the premixing section 12. The stirring assembly 15 is a planar transverse frame, which includes an outer frame, and transverse bars are fixed at intervals within the outer frame. Connecting rods 16 are fixedly connected at both ends of the stirring assembly 15. A perforation 17 is provided on the premixing section 12, which is higher than the overflow baffle 14. The connecting rod 16 includes an inner vertical section 28, the lower end of the inner vertical section 28 is fixedly connected to the transverse frame, and the upper end is fixedly connected to a transverse section 29. The transverse section 29 passes through the perforation 17 and is fixedly connected to the outer vertical section 30. The lower end of the outer vertical section 30 is connected to the screen box body 1 via a support rod 31. The perforation 17 is filled with a rubber sealing plug to prevent leakage of coal slurry from the perforation 17. The overall size of the raw coal feed hopper is relatively large and tall, and the feed chute is fixed to the lower end of the feed hopper. The vibration stirring of the stirring assembly 15 in this embodiment does not affect the feed hopper.

[0049] The screen box body 1 drives the stirring assembly 15 to vibrate and stir in the premixing section 12 through the connecting rod 16. When the raw coal enters the premixing section 12 through the feeding section 11, the flushing pipe 13 flushes water in the reverse direction to the raw coal. With the impact force of the water and the vibration and stirring of the stirring assembly 15, the raw coal and water are quickly mixed to form coal slurry. The coal slurry overflows into the inlet and outlet sections through the overflow baffle 14, and then enters the screening assembly 6 through the discharge section.

[0050] The method for using the uniform thickness screen for coal injection in this embodiment includes the following steps:

[0051] (1) The vibrator 5 drives the screen box body 1 and the screening assembly 6 to vibrate, and the screen box body 1 drives the stirring assembly 15 to vibrate in the feed chute, so that the raw coal and water are quickly mixed in the feed chute to form coal slurry;

[0052] (2) The coal slurry enters the screening assembly 6 for desliming, and the oversize material in the middle of the screening assembly 6 enters the conical mesh frame 8. As the screening assembly 6 vibrates, the polyurethane scrubbing rod 9 scrubs the oversize material, and at the same time, the flushing assembly 10 performs reverse flushing to remove the coal slime adhering to the surface of the oversize material particles, making the surface of the oversize material particles smooth. The smooth surface of the particles reduces the probability of subsequent adhesion of coal slime;

[0053] (3) The scrubbed material on the screen continues to be desludged along the screening assembly 6.

[0054] Example 2

[0055] This embodiment is basically the same as embodiment 1, except that Figure 2 As shown, the screening assembly 6 includes multiple sections of longitudinal screen bodies with successively decreasing inclination angles. The longitudinal screen body with the smallest inclination angle is the final screen body 18. A recoil assembly 19 is fixed below the middle of the final screen body 18. The recoil assembly 19 is a row of flushing nozzles arranged horizontally. The recoil assembly 19 flushes water obliquely upward from the lower side of the final screen body 18, and the flushing direction is opposite to the movement direction of the coal.

[0056] If the desliming particle size is below 1mm, that is, the coal particles below 1mm are the undersize materials, with the vibration screening of the coal material, fine particles of coal material such as particle size 3mm~1mm, or even particle size 5mm~3mm, which are close to the particle size below 1mm, are also likely to become the bottom material of the oversize materials, which hinders the downward movement of coal particles below 1mm and their contact with the screen surface, thereby reducing the desliming efficiency. Continuing through vibration screening and water flushing from the upper side will have little effect.

[0057] In this embodiment, by setting the backflush component 19, the scrubbed oversize material continues to be deslimed along the screening component 6. After entering the middle part of the final screen body 18, the backflush component 19 flushes water obliquely upward from the lower side of the final screen body 18. The fine particles oversize material on the upper surface of the final screen body 18 at the bottom layer are impacted and moved upward by the water, breaking up the accumulation of fine particles at the bottom layer, so that the particle gaps of the oversize material are opened. With the subsequent vibration desliming, it is convenient for the coal slime to contact the screen surface through the particle gaps, thereby facilitating the coal slime to pass through the screen.

[0058] Example 3

[0059] This embodiment is basically the same as embodiment 1, except that Figure 2 、 5 As shown in Figure 6, the screening component 6 includes a polyurethane flexible frame 20, which is composed of positioning grooves 21 arranged in a horizontal and vertical array. Screen sheets 22 are mounted in the positioning grooves 21, and the joints of the upper surfaces of adjacent screen sheets 22 are bonded with waterproof tapes 23. On the one hand, this prevents material from being stuck at the joints to form screening dead corners, and on the other hand, it fixes the screen sheets 22 to prevent them from falling off from the positioning grooves 21.

[0060] Support shafts 24 are fixed at intervals in the screen box body 1 along the conveying direction of the coal material. Figure 7 As shown, the screen box body 1 is provided with a strip hole 25 corresponding to the support shaft 24. The end of the support shaft 24 is connected to the strip hole 25 by a bolt. When the height of the support shaft 24 needs to be adjusted, just loosen the bolt. The support shaft 24 is located at the lower side of the screening assembly 6 and is used to support the screening assembly 6. Figure 2 and 8 As shown, polyurethane elastic blocks 26 are fixed on both sides of the screen box body 1 along the conveying direction of the coal material. The lower end of the polyurethane elastic block 26 is sealed against the edge of the upper side of the screening component 6. The upper side edge of the screening component 6 is sealed and positioned by the polyurethane elastic block 26 to avoid leakage at the edge of the screening component 6.

[0061] The assembly method for screening assembly 6 is as follows: The screen mesh pieces 22 are clipped into the positioning slots 21 of the polyurethane flexible frame 20. Waterproof tape 23 is then applied to the joints between adjacent screen mesh pieces 22 to form the assembled screen body. The screening assembly 6 comprises multiple longitudinal screen sections with decreasing inclination angles. The number and height of the corresponding support shafts 24 are adjusted based on the longitudinal length and inclination angle of the longitudinal screen sections. The assembled screen body is then placed on the support shafts 24. Finally, polyurethane elastic blocks 26 are installed at both ends of the upper side of the screen body.

[0062] like Figure 2 As shown, a height-adjustable fixed shaft 27 is installed at the upper end of the under-screen hopper 4. The fixed shaft 27 is staggered with the support shaft 24. The fixed shaft 27 is against the lower side of the screening component 6. When the screening component 6 vibrates, its lower side collides with the fixed shaft 27, which facilitates the pore-blocking material to escape from the sieve holes of the screening component 6.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A uniform thickness screen for pulverized coal injection, comprising a screen box body, a vibrator provided on the screen box body, and screening assemblies with multiple inclination angles provided longitudinally within the screen box body, characterized in that: A scrubbing assembly is fixed on the upper side of the middle of the screening assembly. The scrubbing assembly includes a horizontal conical mesh frame filled with polyurethane scrubbing rods. The diameter of the polyurethane scrubbing rods is larger than the aperture of the conical mesh frame, and the aperture of the conical mesh frame is larger than the particle size of the raw coal. A flushing assembly is provided above the discharge side of the conical mesh frame. The flushing direction of the flushing assembly is opposite to the movement direction of the coal. A feeding chute is provided at the feeding end of the screening assembly. A stirring assembly is provided in the feeding chute. The stirring assembly passes through the feeding chute and is connected to the screen box body. The feed chute includes a feed section, a premixing section, and a discharge section connected in sequence. The feed end of the premixing section is provided with a flushing pipe, and the flushing direction of the flushing pipe is opposite to the movement direction of the raw coal. The discharge end of the premixing section is provided with an overflow baffle. The stirring assembly is located in the premixing section. The stirring assembly is a flat horizontal frame. Connecting rods are fixed at both ends of the stirring assembly. A perforation is provided on the premixing section. The perforation is higher than the overflow baffle. The connecting rod passes through the perforation and is connected to the screen box body. A rubber sealing plug is provided at the perforation. The screening assembly includes a polyurethane flexible frame, which is composed of positioning grooves arranged in a horizontal and vertical array. Screen sheets are fixed in the positioning grooves, and waterproof tape is bonded to the joints of the upper surfaces of adjacent screen sheets. Support shafts are arranged at intervals in the screen box body along the conveying direction of the coal material. The height of the support shafts is adjustable. The support shafts are located on the lower side of the screening assembly and are used to support the screening assembly. By adjusting the height of the support shafts and the number of support shafts corresponding to each section of the longitudinal screen body, the length and inclination angle of each section of the longitudinal screen body can be adjusted.

2. The uniform thickness screen for pulverized coal injection according to claim 1, characterized in that: The screening assembly includes multiple sections of longitudinal screen bodies with successively decreasing inclination angles. The longitudinal screen body with the smallest inclination angle is the last section of the screen body. A recoil assembly is provided below the middle of the last section of the screen body. The recoil assembly flushes water from the lower side of the last section of the screen body at an angle upward, and the flushing direction is opposite to the movement direction of the coal.

3. The uniform thickness screen for pulverized coal injection according to claim 1, characterized in that: Polyurethane elastic blocks are fixed on both sides of the screen box body along the conveying direction of the coal material, and the lower ends of the polyurethane elastic blocks are sealed against the edge of the upper side of the screening component.

4. A uniform thickness screen for pulverized coal injection according to claim 1 or 3, characterized in that: An under-screen hopper is provided below the screening assembly, and a fixed shaft is provided at the upper end of the under-screen hopper, which abuts against the lower side of the screening assembly.

5. The method for using the uniform thickness screen for pulverized coal injection according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) The vibrator drives the screen box body and the screening assembly to vibrate, and the screen box body drives the stirring assembly to vibrate in the feed chute, so that the raw coal and water are mixed in the feed chute to form coal slurry; (2) The coal slurry enters the screening assembly for desliming, and the oversize material in the middle of the screening assembly enters the conical mesh frame. As the screening assembly vibrates, the polyurethane scrubbing rod scrubs the oversize material, and at the same time, the flushing assembly performs reverse flushing to wipe off the coal slime adhering to the surface of the oversize material particles, making the surface of the oversize material particles smooth; (3) The scrubbed material on the screen continues to be desludged along the screening assembly.

6. The method of use according to claim 5, characterized in that: In step (3), the scrubbed oversize material continues to be deslimed along the screening assembly. After entering the middle of the final screen body, the backflush assembly flushes water from the lower side of the final screen body at an angle upward. The fine particles on the upper surface of the final screen body are moved upward by the water impact, so that the gaps between the particles of the oversize material are opened. With the subsequent vibration desliming, the coal slime is facilitated to contact the screen surface through the gaps between the particles and pass through the screen.

7. The method of use according to claim 5, characterized in that: In step (1), when the raw coal enters the premixing section through the feeding section, the water pipe flushes the raw coal in the reverse direction. With the impact force of the water and the vibration stirring of the stirring assembly, the raw coal and water are mixed to form coal slurry. The coal slurry overflows into the discharge section through the overflow baffle, and then enters the screening assembly through the discharge section.

8. The method of use according to claim 5, characterized in that: In steps (1) to (3), when the screening assembly vibrates, the lower side of the screening assembly collides and vibrates with the fixed shaft, causing the blocking material to separate from the sieve holes of the screening assembly.

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