A vibrating screening device for adjusting the particle size distribution of coal slurry

Abstract

This invention discloses a vibrating screening device for adjustable coal slurry particle size distribution, relating to the field of coal slurry screening technology. It includes: a segmented screen box, the interior of which is divided into at least two vibration zones along the coal slurry flow direction; a screening component disposed within each vibration zone, the screening component being adjustable in terms of particle size; an excitation system disposed on the segmented screen box, the excitation system being used to apply independently adjustable harmonic excitation to each vibration zone; a feed hopper disposed above the feed end of the segmented screen box; and a microbubble generating component disposed inside the feed hopper, injecting microbubbles into the coal slurry. This invention possesses significant advantages such as multi-zone heterogeneous vibration, stepless orifice adjustment for coal slurry particle size, and microbubble anti-clogging and screen cleaning, significantly improving the separation efficiency of coarse and fine particles and meeting the need for refined adjustment of coal slurry particle size distribution under different working conditions.

Description

Technical Field

[0001] This invention relates to the field of coal slurry screening technology, and more particularly to a vibrating screening device with adjustable coal slurry particle size distribution. Background Technology

[0002] In industrial production processes such as coal-water slurry preparation, coal slime flotation, and wet mineral processing, the particle size distribution of coal slurry is a key indicator affecting product quality, conveying efficiency, and subsequent reaction effects. As the core equipment for controlling the particle size distribution of coal slurry, the vibrating screen's screening efficiency, adjustment precision, and operational stability directly determine production efficiency. Currently, traditional coal slurry vibrating screens generally suffer from structural defects, making it difficult to meet the requirements of refined, intelligent, continuous, and stable industrial production.

[0003] Traditional vibrating screens typically employ a single vibration zone and in-phase excitation structure, resulting in a limited range of screen surface vibration patterns. This makes it difficult to create a strong shear flow field on the screen surface, failing to effectively disperse particle agglomerates that easily form in high-concentration coal slurries. Consequently, this leads to insufficient stratification of coarse and fine particles and low separation efficiency. Furthermore, the rigid screen mesh used in traditional screening devices has a fixed and non-adjustable aperture, making it impossible to continuously and dynamically change the screening size according to operating conditions. This limits the ability to achieve precise online control of coal slurry particle size distribution and restricts its applicability.

[0004] In actual screening processes, fine and sticky particles in coal slurry are prone to bridging, adhesion, and blockage at the screen openings. Existing equipment lacks efficient online self-cleaning methods, which can easily lead to a continuous decline in screening efficiency, requiring frequent shutdowns for cleaning and seriously affecting the stability of continuous production. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a vibrating screening device with adjustable coal slurry particle size distribution.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A vibrating screen device with adjustable coal slurry particle size distribution, comprising: The segmented screen box is divided into at least two vibration zones along the coal slurry flow direction. A screening assembly is disposed inside each vibration zone, and the screening assembly can adjust the screening particle size; The excitation system is installed on the segmented screen box, and the excitation system is used to apply simple harmonic excitation with independently adjustable phase to each vibration zone; A feed hopper is located above the feed end of the segmented screen box; A microbubble generating component is installed inside the feed hopper to inject microbubbles into the coal slurry.

[0007] As a further improvement of the present invention, the phase difference between adjacent vibration zones is 30°-180°.

[0008] As a further improvement of the present invention, the screening assembly includes a screen plate fixed inside a segmented screen box, and the screen plate corresponds to the position of the vibration zone. The screen plate is evenly distributed with screen holes. Below the screen plate is a silicon steel sheet fixedly connected to the screen plate. The silicon steel sheet is evenly distributed with grid holes, and the grid holes are located directly below the screen holes. There is a gap between the silicon steel sheet and the screen plate. An elastic membrane layer is provided between the screen plate and the silicon steel sheet. The interior of the elastic membrane layer is filled with magnetorheological fluid. Below each grid hole is a concentric annular micro electromagnetic coil. The concentric annular micro electromagnetic coil is installed at the lower end of the silicon steel sheet. The center of the concentric annular micro electromagnetic coil is provided with a T-shaped iron core.

[0009] As a further improvement of the present invention, the microbubble generating component includes an aeration pipe disposed inside the feed hopper, both ends of which extend through the feed hopper and are rotatably mounted to the feed hopper. A motor is mounted on the outer wall of the feed hopper, and the output shaft of the motor is fixedly connected to one end of the aeration pipe. The other end of the aeration pipe is connected to a first connecting pipe via a rotary vent connector. The first connecting pipe is connected to a first air pump. Aeration holes are evenly distributed on the surface of the aeration pipe. A stirring mechanism is arranged on the aeration pipe. A first inclined plate located above the aeration pipe is fixed inside the feed hopper, and a second inclined plate located below the aeration pipe is fixed inside the feed hopper. The second inclined plate is provided with a flow guiding bend.

[0010] As a further improvement of the present invention, the sieve hole is a conical structure that is wider at the top and narrower at the bottom. The sieve plate is provided with an air chamber inside. The inner wall of the sieve hole is provided with a waterproof and breathable membrane that communicates with the air chamber. The air chamber is connected to a second connecting pipe. The second connecting pipe extends into a segmented sieve box and is connected to a second air pump.

[0011] As a further improvement of the present invention, the stirring mechanism includes a fixed ring fixedly sleeved on the aeration pipe, and a plurality of stirring teeth are fixed on the fixed ring, the plurality of stirring teeth being evenly distributed along the circumference of the fixed ring.

[0012] As a further improvement of the present invention, a base plate is provided below the segmented screen box, and a bracket is fixed at the upper end of the base plate. The segmented screen box and the bracket are connected by a spring support.

[0013] As a further improvement of the present invention, fixing rods are fixed on both opposite side walls of the feed hopper, and the end of the fixing rod away from the feed hopper is fixed on the bracket.

[0014] The beneficial effects of this invention are: This invention creates a strong shear flow field during the screening process by dividing the interior of the segmented screen box into at least two vibration zones along the flow direction of the coal slurry and a phase difference of 30° to 180°. This effectively breaks up the particle agglomerates in the coal slurry and changes the movement trajectory and loose stratification of the particles on the screen surface. Compared with in-phase vibration, this invention significantly improves the separation efficiency of coarse and fine particles.

[0015] This invention utilizes the combination of concentric ring-shaped micro electromagnetic coils and T-shaped iron cores in the screening assembly to achieve precise control of the solidification morphology of magnetorheological fluid. By independently adjusting the current of each coil through a computer, the thickness of the magnetic column can be precisely adjusted, enabling real-time and stepless control of the actual screen gap size. This meets the need for fine adjustment of coal slurry particle size distribution under different working conditions and overcomes the defects of fixed aperture in traditional rigid screens.

[0016] This invention solves the problem of bridging and clogging of difficult-to-screen particles at the screen holes by setting a waterproof and breathable membrane inside the screen holes that communicates with the air chamber and using a second air pump to launch microbubbles to the inner wall of the screen holes, thus greatly improving the self-cleaning ability and operational stability of the screening device.

[0017] The present invention has an aeration pipe and stirring teeth driven by a motor installed inside the feed hopper. Microbubbles are injected into the coal slurry by a first air pump. The guiding effect of the first and second inclined plates makes the coal slurry fully contact the microbubbles, which effectively changes the rheological properties of the coal slurry, reduces the viscosity of the coal slurry, thereby improving the flowability of the coal slurry on the screen plate and increasing the overall screening speed. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a vibrating screening device with adjustable coal slurry particle size distribution proposed in this invention from one perspective. Figure 2 This is a schematic diagram of the structure of a vibrating screening device with adjustable coal slurry particle size distribution proposed in this invention from another perspective. Figure 3 This is a schematic cross-sectional view of the feed hopper, first inclined plate, second inclined plate, guide bend, and aeration pipe of a vibrating screening device for adjustable coal slurry particle size distribution proposed in this invention. Figure 4 This is a schematic diagram of the structure of a vibrating screen device for adjusting the particle size distribution of coal slurry, including a fixed rod, a feed hopper, a motor, a rotary venting joint, a second connecting pipe, and a second air pump, as proposed in this invention. Figure 5 This is a schematic diagram of the aeration pipe, rotary air connector, second connecting pipe, and motor of a vibrating screening device for adjustable coal slurry particle size distribution proposed in this invention. Figure 6 for Figure 5 Enlarged view of point A in the middle; Figure 7 This is a cross-sectional schematic diagram of the screening component of a vibrating screening device for adjustable coal slurry particle size distribution proposed in this invention.

[0019] In the diagram: 1. Base plate, 2. Support frame, 3. Segmented screen box, 4. Spring support, 5. Vibration system, 6. Fixed rod, 7. Feed hopper, 8. Vibration zone, 9. Screen plate, 10. First air pump, 11. First connecting pipe, 12. Second air pump, 13. Second connecting pipe, 14. First inclined plate, 15. Second inclined plate, 16. Guide bend, 17. Aeration pipe, 18. Rotary ventilation joint, 19. Motor, 20. Aeration hole, 21. Fixed ring, 22. Stirring teeth, 23. Screen hole, 24. Air chamber, 25. Waterproof and breathable membrane, 26. Elastic membrane layer, 27. Magnetorheological fluid, 28. Silicon steel sheet, 29. Grid hole, 30. Concentric ring-shaped miniature electromagnetic coil, 31. T-shaped iron core. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] See Figures 1-7 A vibrating screen device with adjustable coal slurry particle size distribution, comprising: The segmented screen box 3 is divided into two vibration zones along the flow direction of the coal slurry. The adjacent vibration zones are independent of each other and form a continuous screening channel. The phase difference between the adjacent vibration zones is 30°-180°. For example, at the same time, the first zone is at a vibration period of 0°, which means that the first zone is moving downwards at this moment. The second zone is at a vibration period of 90°, which means that the second zone has reached the highest point and is preparing to move downwards. If the first zone and the second zone vibrate up and down at the same time (in the same phase), the coal slurry will only be "thrown up and then fall down as a whole". The particles hardly move against each other. The phase difference can change the looseness and stratification of the coal slurry. Due to the different phases, a "shear flow field" will be created. The coal slurry will be stretched, sheared and rotated, just like kneading dough by hand. This shear force will break up the agglomeration of particles in the coal slurry, making it easier to separate coarse and fine particles and change the movement trajectory of particles on the screen surface. The screening assembly is located inside each vibration zone. The screening assembly allows for adjustment of the screening particle size. It includes a screen plate 9 fixed inside the segmented screen box 3, with the screen plate 9 corresponding to the vibration zone 8. Screen holes 23 are evenly distributed on the screen plate 9. Below the screen plate 9 is a silicon steel sheet 28 fixedly connected to it. The silicon steel sheet 28 has evenly distributed grid holes 29, located directly below the screen holes 23. A gap exists between the silicon steel sheet 28 and the screen plate 9. An elastic membrane layer 26, made of polyurethane, is provided between the screen plate 9 and the silicon steel sheet 28. This elastic membrane layer 26 is wear-resistant and non-magnetic, serving a sealing function and transmitting magnetic force. The elastic membrane layer 26 is 2-5 mm thick. The flat, sealed space contains an elastic membrane layer 26 filled with magnetorheological fluid 27. Each grid hole 29 has a concentric ring-shaped micro-electromagnetic coil 30 below it. When the concentric ring-shaped micro-electromagnetic coil 30 is energized, the magnetic particles of the magnetorheological fluid 27 located directly above the coil and below the sieve hole 23 instantly align along the magnetic field direction to form columnar magnetic columns, exhibiting solid-like properties. The gap between the magnetic columns and the sieve hole 23 is the actual sieve gap. This phase transition is reversible, continuous, and controllable. Changing the magnetic field strength alters the "hardness" and shape after solidification. Each concentric ring-shaped micro-electromagnetic coil 30 can be independently switched on / off or its current adjusted (computer-controlled). Furthermore, coils at different points on the rings of the concentric ring-shaped micro-electromagnetic coil 30 can be individually controlled, allowing precise control of the magnetic column thickness. Because the magnetic field strength is controllable, the magnetic column can be made thicker (higher current) or thinner (lower current), thus allowing real-time, stepless adjustment of the sieve gap size (e.g., from 2mm). The particle size is continuously varied up to 0.5 mm, thereby adjusting the screening particle size.

[0022] The non-solidified liquid magnetorheological fluid 27 is fluid. Under the action of feeding pressure or gravity, the elastic membrane layer 26 and the magnetorheological fluid 27 can collapse downward, allowing the particles in the coal slurry to flow along the elastic membrane layer 26 without clogging. The concentric ring-shaped micro electromagnetic coil 30 is installed at the lower end of the silicon steel sheet 28. The center of the concentric ring-shaped micro electromagnetic coil is provided with a T-shaped iron core 31. The T-shaped iron core 31 acts as a "clustering device" to gather the scattered magnetic field generated by the concentric ring-shaped micro electromagnetic coil 30 into a concentrated, vertical strong magnetic bundle.

[0023] The sieve aperture 23 has a conical structure that is wider at the top and narrower at the bottom. The sieve plate 9 has an air chamber 24 inside. A waterproof and breathable membrane 25 communicating with the air chamber 24 is provided on the inner wall of the sieve aperture 23. The air chamber 24 is connected to a second connecting pipe 13, which extends into a segmented sieve box 3 and is connected to a second air pump 12. The second air pump 12 pumps air into the air chamber 24, and then emits microbubbles into the sieve aperture 23 through the waterproof and breathable membrane 25. When particles in the coal slurry smaller than but close to the size of the sieve aperture 23 (difficult-to-screen particles) are present... It is easy for a "bridging" phenomenon to form at the sieve hole 23. Several particles squeeze each other and get stuck on the sieve hole 23, causing the sieve plate 9 to be blocked. When the particles attach to the air bubbles and generate lift to try to float upward, they will be tightly squeezed on the upper wide part of the sieve hole of the conical structure. The particles want to "float" out, but are physically locked by the structure of the sieve hole 23. Under the continuous "pushing force" provided by the air bubbles and the "guiding effect" of the conical structure, the particles are forced to move downward (through the sieve side) where the resistance is less, until they break free from the air bubbles or squeeze through the narrowest part.

[0024] The excitation system 5 is installed on the segmented screen box 3. The excitation system 5 includes a PLC controller, a frequency converter, a servo motor, and a vibrator. The PLC controller sends instructions to the servo motor through the frequency converter. The servo motor has its own encoder. The encoder monitors the rotation angle of each motor in real time and automatically fine-tunes the output of the frequency converter to ensure that the angle difference is always kept at the set value. The excitation system 5 is used to apply simple harmonic excitation with independently adjustable phase to each vibration zone. The feed hopper 7 is located above the feed end of the segmented screen box 3. The bottom plate 1 is located below the segmented screen box 3. The upper end of the bottom plate 1 is fixed with a bracket 2. The segmented screen box 3 and the bracket 2 are connected by a spring support 4. Fixing rods 6 are fixed on the opposite side walls of the feed hopper 7. The end of the fixing rod 6 away from the feed hopper 7 is fixed on the bracket 2.

[0025] A microbubble generating component is installed inside the feed hopper 7 to inject microbubbles into the coal slurry. The component includes an aeration pipe 17 inside the feed hopper 7, with both ends extending out of the hopper 7 and rotatably mounted thereto. A motor 19 is mounted on the outer wall of the feed hopper 7, and the output shaft of the motor 19 is fixedly connected to one end of the aeration pipe 17. The other end of the aeration pipe 17 is connected to a first connecting pipe 11 via a rotary vent joint 18. The rotary vent joint 18 ensures gas flow while the aeration pipe 17 rotates. The first connecting pipe 11 is connected to a first air pump 10 for aeration. The surface of the tube 17 is evenly distributed with aeration holes 20, the diameter of which is 50–150 μm. A stirring mechanism is arranged on the aeration tube 17. The stirring mechanism includes a fixed ring 21 fixedly sleeved on the aeration tube 17. Multiple stirring teeth 22 are fixed on the fixed ring 21. The multiple stirring teeth 22 are evenly distributed along the circumference of the fixed ring 21. The aeration tube 17 is driven to rotate by the motor 19. The aeration tube 17 drives the fixed ring 21 and stirring teeth 22 to rotate. Thus, during the process of introducing microbubbles into the coal slurry using the aeration tube 17, the stirring teeth 22 can be used to stir the coal slurry, so that the microbubbles and coal slurry can be fully and evenly contacted.

[0026] The feed hopper 7 has a first inclined plate 14 fixed inside, located above the aeration pipe 17, and a second inclined plate 15 fixed inside, located below the aeration pipe 17. The second inclined plate 15 is provided with a flow guiding bend 16. The first inclined plate 14 and the second inclined plate 15 can guide the coal slurry to the aeration pipe 17, so that the coal slurry can fully contact the aeration pipe 17, and thus fully fill the coal slurry with microbubbles. The presence of microbubbles can change the rheological properties of the coal slurry, making the coal slurry looser and reducing its viscosity, thereby improving the flowability of the coal slurry on the screen surface of the screen plate 9, allowing the coal slurry to pass through the screen plate 9 more smoothly and increasing the screening speed.

[0027] In actual operation, the amount of microbubbles generated can be controlled by adjusting the flow rate of the first air pump 10 to adapt to different coal slurry properties and screening requirements. For example, when there are many fine particles or high viscosity in the coal slurry, the bubble flow rate can be appropriately increased to enhance the above-mentioned effect.

[0028] When this invention is used, coal slurry from the outside first enters the feed hopper 7, the motor 19 is started and drives the aeration pipe 17 to rotate, the fixing ring 21 and stirring teeth 22 fixed on the aeration pipe 17 rotate accordingly to stir the coal slurry, at the same time the first air pump 10 supplies air to the aeration pipe 17 through the first connecting pipe 11 and the rotating air connector 18, the gas releases microbubbles with a diameter of 50 to 150 micrometers through the aeration holes 20 on the surface of the aeration pipe 17, and the first inclined plate 14 and the second inclined plate 15 cooperate to guide the coal slurry to the area of ​​the aeration pipe 17 to ensure full contact. The microbubbles play a role in reducing viscosity and loosening in the coal slurry, and then the coal slurry enters the segmented screen box 3; The servo motor in the vibration system 5 applies simple harmonic excitation to the segmented screen box 3 through the vibrator. The PLC controller monitors and adjusts the phase difference of each vibration zone through the frequency converter and encoder, so that the adjacent zones generate a phase difference of 30 to 180 degrees to form a shear flow field to disperse the particle agglomeration. The coal slurry flows through the screen plate 9, and the second air pump 12 pumps air to the air chamber 24 through the second connecting pipe 13. The gas passes through the waterproof and breathable membrane 25 and enters the inner wall of the screen hole 23 to generate a micro bubble curtain to assist in anti-blocking and deagglomeration. When it is necessary to adjust the particle size of the coal slurry, the computer controls the concentric ring-shaped micro electromagnetic coil 30 to be energized. The T-shaped iron core 31 located directly below the screen hole 23 concentrates the magnetic field and acts on the magnetorheological fluid 27 in the elastic membrane layer 26, causing it to solidify instantly to form a magnetic column. By controlling the concentric ring-shaped micro electromagnetic coil 30, the thickness of the magnetic column can be precisely controlled, thereby adjusting the actual screen gap size between the magnetic column and the screen hole 23. The coal slurry completes particle size separation on the screen plate 9. Fine particles fall through the screen hole 23 and the gap between the magnetic column, while coarse particles move towards the discharge end under the action of vibration and shearing and are finally discharged.

[0029] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A vibrating screen device with adjustable coal slurry particle size distribution, characterized in that, include: The segmented screen box (3) is divided into at least two vibration zones along the coal slurry flow direction. A screening assembly is disposed inside each vibration zone, and the screening assembly can adjust the screening particle size; The excitation system (5) is installed on the segmented screen box (3). The excitation system (5) is used to apply simple harmonic excitation with independently adjustable phase to each vibration zone. The feed hopper (7) is located above the feed end of the segmented screen box (3); The microbubble generating component is located inside the feed hopper (7) and injects microbubbles into the coal slurry.

2. The vibrating screen device for adjusting the particle size distribution of coal slurry according to claim 1, characterized in that, The phase difference between adjacent vibration zones is 30°-180°.

3. The vibrating screen device with adjustable coal slurry particle size distribution according to claim 1, characterized in that, The screening assembly includes a screen plate (9) fixed inside a segmented screen box (3), and the screen plate (9) corresponds to the position of the vibration zone (8). The screen plate (9) is evenly distributed with screen holes (23). Below the screen plate (9) is a silicon steel sheet (28) fixedly connected to the screen plate (9). The silicon steel sheet (28) is evenly distributed with grid holes (29), and the grid holes (29) are located directly below the screen holes (23). There is a gap between the silicon steel sheet (28) and the screen plate (9). An elastic membrane layer (26) is provided between the screen plate (9) and the silicon steel sheet (28). The interior of the elastic membrane layer (26) is filled with magnetorheological fluid (27). Below each grid hole (29) is a concentric ring-shaped micro electromagnetic coil (30). The concentric ring-shaped micro electromagnetic coil (30) is installed at the lower end of the silicon steel sheet (28). The center of the concentric ring-shaped micro electromagnetic coil is provided with a T-shaped iron core (31).

4. The vibrating screen device with adjustable coal slurry particle size distribution according to claim 1, characterized in that, The microbubble generating component includes an aeration pipe (17) disposed inside the feed hopper (7). Both ends of the aeration pipe (17) extend out of the feed hopper (7) and are rotatably mounted to the feed hopper (7). A motor (19) is mounted on the outer wall of the feed hopper (7). The output shaft of the motor (19) is fixedly connected to one end of the aeration pipe (17). The other end of the aeration pipe (17) is connected to a first connecting pipe (11) via a rotary air connector (18). The first connecting pipe (11) is connected to a first air pump (10). Aeration holes (20) are evenly distributed on the surface of the aeration pipe (17). A stirring mechanism is arranged on the aeration pipe (17). A first inclined plate (14) located above the aeration pipe (17) is fixed inside the feed hopper (7). A second inclined plate (15) located below the aeration pipe (17) is fixed inside the feed hopper (7). A guide bend (16) is provided on the second inclined plate (15).

5. The vibrating screen device for adjusting the particle size distribution of coal slurry according to claim 3, characterized in that, The sieve hole (23) is a conical structure that is wider at the top and narrower at the bottom. The sieve plate (9) is provided with an air chamber (24). The inner wall of the sieve hole (23) is provided with a waterproof and breathable membrane (25) that communicates with the air chamber (24). The air chamber (24) is connected to a second connecting pipe (13). The second connecting pipe (13) extends out to a segmented sieve box (3) and is connected to a second air pump (12).

6. The vibrating screen device for adjusting the particle size distribution of coal slurry according to claim 4, characterized in that, The stirring mechanism includes a fixed ring (21) fixedly sleeved on the aeration pipe (17), and a plurality of stirring teeth (22) are fixed on the fixed ring (21), and the plurality of stirring teeth (22) are evenly distributed along the circumference of the fixed ring (21).

7. The vibrating screen device with adjustable coal slurry particle size distribution according to claim 1, characterized in that, The segmented screen box (3) is provided with a base plate (1) at the bottom, and a bracket (2) is fixed at the upper end of the base plate (1). The segmented screen box (3) and the bracket (2) are connected by a spring support (4).

8. The vibrating screen device for adjusting the particle size distribution of coal slurry according to claim 7, characterized in that, The feed hopper (7) has fixed rods (6) on both sides of its opposite sides. The end of the fixed rod (6) away from the feed hopper (7) is fixed to the bracket (2).

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