A spray dust-settling device for coal screening

Abstract

The application discloses a kind of coal screening with spray dust-settling device, belong to coal mine dust pollution prevention and control field.The device includes dust hood, and the dust hood one end inside is surrounded and is provided with front cohesive nozzle group;The dust hood other end inside is surrounded and is provided with discharge nozzle group;The dust hood inside two sides are provided with to spray curtain nozzle group;The dust hood top is provided with negative pressure suction cavity, and the negative pressure suction cavity is connected with negative pressure component.The application in the application, front cohesive nozzle group is fixedly connected with the inner wall of dust hood, and nozzle is inwardly inclined to form convergent mist curtain.To spray curtain nozzle group is arranged in the inside two sides of dust hood, and left and right two rows of nozzles are horizontally opposite and spray, form two opposing mist walls, and transverse airflow cancels each other, dust cannot overflow to cover wall.The discharge nozzle group discharge capacity is less than front cohesive nozzle group, and small-angle push is sent along coal flow.Make that dust-settling effect no longer depends on external environment, and the controllability of dust-settling process is stronger, and better dust-settling effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of coal mine dust pollution control technology, specifically to a spray dust suppression device for coal screening. Background Technology

[0002] In coal washing plants, raw coal, transported from the mine, is a mixture of large and small particles. Direct combustion of this mixture leads to low boiler efficiency and excessive emissions. Upon arrival at the plant, the coal is first screened using meshes of different sizes to classify it by particle size: large pieces (>50mm) are used as power coal or coke feedstock and stacked separately; medium pieces (25-50mm) are used in stoker boilers; and fine powder (<25mm) is sent for blending or briquetting. After grading and stacking, different users take only what they need, which improves combustion efficiency and reduces dust pollution.

[0003] Dust is generated during coal screening due to vibration. Dust suppression is typically achieved through spraying. The principle involves a high-pressure pump pressurizing water to 3-7 MPa, which is then atomized into fine water droplets of 10-50 μm through nozzles. The water mist collides with and adsorbs dust particles, causing them to become heavier and settle, while simultaneously suppressing re-entrainment. During installation, main pipes are generally laid along the head and tail of the conveyor belt, the material drop point of the screening machine, the edge of the stockpile, and the top of the silo. Branch pipes are equipped with nozzles, spaced approximately 3-5 meters apart, and angled downwards at 15°-30° to cover the dust source. Control methods typically involve automatic start / stop of the conveyor belt or automatic opening / closing based on dust concentration sensors, saving water and avoiding excessive wetting of the material.

[0004] However, the aforementioned methods for controlling coal mine dust pollution still have the following drawbacks: the contact window between droplets and dust is extremely short. Droplets are deflected and drift out of the effective range before colliding with dust, shortening the effective range. Simultaneously, fine dust particles, due to their low inertia, escape directly by bypassing the droplets with the airflow. In high-temperature environments during summer, where the surface temperature of the stockpile can reach up to 60°C, droplet evaporation accelerates, and dust vaporizes before it can adsorb it, causing a sharp drop in dust suppression efficiency. This results in poor controllability in the aforementioned operating environments, affecting the effectiveness of the method. Summary of the Invention

[0005] The purpose of this invention is to provide a spray dust suppression device for coal screening, so as to solve the problem that existing spray dust suppression devices are easily affected by environmental factors such as airflow and temperature.

[0006] The technical problem to be solved by the present invention can be achieved through the following technical solution: A spray dust suppression device for coal screening, comprising a dust removal hood, wherein a front cohesive nozzle group is arranged around the inside of one end of the dust removal hood, the nozzles in the front cohesive nozzle group are inclined inward and the spray angle is directed towards the center inside the hood to form a converging mist curtain to lock in the original dust generated by the impact of falling coal; a discharge nozzle group is arranged around the inside of the other end of the dust removal hood, the nozzles in the discharge nozzle group are inclined outward and gently push the discharge in the direction of coal flow to slowly guide the mist-containing material. Dust flows towards the bottom of the discharge area and settles; inside the dust collector hood, there are two opposing spray curtain nozzle groups on both sides, with two rows of nozzles spraying horizontally towards each other, covering the entire width of the screen surface to form two opposing mist walls, forcing the suspended dust to move slowly towards the center of the screen surface; the top of the dust collector hood is equipped with a negative pressure suction chamber, which is connected to a negative pressure component. The bottom of the negative pressure suction chamber is equipped with a negative pressure suction port that communicates with the inside of the dust collector hood, providing a negative pressure environment inside the dust collector hood and balancing the total air volume sprayed from the three zones of nozzles.

[0007] Preferably, the negative pressure suction ports are provided in multiple sets, and are sparser closer to the negative pressure source and denser further away from the negative pressure source, so as to maintain a balanced negative pressure difference inside the dust removal hood.

[0008] Preferably, the negative pressure suction chamber is distributed along the top extension direction of the dust removal hood, and the negative pressure suction port is set on both sides of the negative pressure suction chamber to avoid the nozzles spraying directly into the negative pressure suction port.

[0009] Preferably, the dust collector hood has side wall inspection ports on both sides, and a side flap is movably provided on the upper side of the side wall inspection port. The side flap can be flipped up to display the internal environment of the dust collector hood.

[0010] Preferably, the dust cover is equipped with a differential pressure sensor and a humidity sensor.

[0011] Preferably, a negative pressure chamber is provided at the top of the negative pressure suction chamber, a dust removal chamber is provided at the bottom of the negative pressure suction chamber, and the negative pressure suction port is opened on both sides of the top of the dust removal chamber. Preferably, a guide plate is provided between the dust removal chamber and the negative pressure chamber. The guide plate guides the airflow to the bottom of the dust removal chamber. After passing the lower end of the guide plate, the airflow enters the negative pressure chamber along the guide plate. A dust collection tray is slidably fitted inside the dust removal chamber. Dust falls onto the dust collection tray under the action of gravity.

[0012] Preferably, partitions are fixedly installed at equal intervals at the bottom of the dust removal hood.

[0013] Preferably, the nozzles in the spray curtain nozzle group are fixedly equipped with nozzle protective covers to prevent coal from impacting them.

[0014] Preferably, the negative pressure suction chamber is connected to a cyclone separator, the air supply end of the cyclone separator is connected to a bag filter, and the air supply end of the bag filter is connected to a negative pressure fan.

[0015] Preferably, the dust removal hood maintains a slight negative pressure of -5 to -10 Pa.

[0016] Compared with the prior art, the beneficial effects of this application are as follows: 1. In this invention, the front cohesive nozzle assembly is fixedly connected to the inner wall of the dust collector hood. The nozzles tilt inward to form a converging mist curtain, causing the airflow to converge towards the center of the hood, forming a pressure barrier with the feed inlet. This prevents crosswinds from blowing away the mist field and simultaneously traps the primary dust generated by the impact of falling coal. The spray curtain nozzle assembly is located on both sides inside the dust collector hood, with two rows of nozzles spraying horizontally towards each other, forming two opposing mist walls. The transverse airflows cancel each other out, preventing dust from overflowing out of the hood wall. Instead, the dust is forced to move towards the center of the screen surface, significantly increasing the probability of contact with atomized water droplets. This area is the main dust removal zone. The discharge nozzle assembly has a smaller discharge capacity than the front cohesive nozzle assembly, pushing the material at a small angle with the coal flow to maintain the lowest possible air pressure at the discharge end. The negative pressure suction chamber is connected to the inside of the dust removal hood. Through the negative pressure suction port, the total air volume of the three-zone nozzles is balanced. The inside of the hood is always kept in a slightly negative pressure state, and the mist does not bulge outward. This makes the dust reduction effect no longer dependent on the external environment, and the dust reduction process is more controllable, achieving a better dust reduction effect.

[0017] 2. In this invention, the negative pressure suction chamber is arranged along the top extension direction of the dust collector hood, and the negative pressure suction port is located on both sides of the negative pressure suction chamber rather than at the bottom. Dust must first detour to the sides before entering the negative pressure suction port, increasing the movement distance. At the same time, more atomized water droplets are also closer to this area, increasing the probability of dust and water droplet contact and effectively reducing the subsequent dust removal pressure. Side wall inspection ports are opened on both sides of the dust collector hood, and side flaps are movably connected to the upper side of the side wall inspection ports. When the side flaps are opened upwards, the internal environment is exposed and the inner side is flipped outwards, making it easy to clean the moist peat layer accumulated on the inner walls of both sides of the negative pressure suction chamber.

[0018] 3. In this invention, a negative pressure chamber is located at the top of the negative pressure suction chamber, and a dust collection chamber is located at the bottom. Negative pressure suction ports are located on both sides of the top of the dust collection chamber. Symmetrical guide plates, in an inverted L-shape, are fixed between the dust collection chamber and the negative pressure chamber. Airflow is guided by the guide plates to the bottom of the dust collection chamber and then upwards into the negative pressure chamber along the guide channel. A sliding dust collection tray is installed inside the dust collection chamber, and dust falls onto the tray under gravity. After a period of use, the surfaces of the guide plates and the dust collection tray become wet, making it easier for dust to adhere. Since the dust's movement speed is less than that of water droplets, it is easier for the dust to combine with water droplets or impact the wet surface, increasing gravity settling. This structure eliminates the need for an additional cyclone separator or bag filter, directly intercepting and collecting most of the dust within the chamber. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the structure during maintenance of the present invention; Figure 2 This is a schematic diagram of the structure when the present invention is in use; Figure 3 This is a schematic diagram of the negative pressure suction port distribution structure of the present invention; Figure 4 This is a schematic diagram of the structure of the second embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the third embodiment of the present invention; Figure 6 This is a schematic diagram of the internal structure of the negative pressure suction chamber in the third embodiment of the present invention; Figure 7 This is a schematic diagram of the partition structure of the present invention; Figure 8 yes Figure 7 A magnified schematic diagram of the structure at point A in the middle.

[0020] Explanation of reference numerals in the attached figures: 1. Dust hood; 101. Side wall inspection port; 102. Side flap; 2. Front cohesive nozzle assembly; 3. Spray curtain nozzle assembly; 301. Nozzle protective cover; 4. Discharge nozzle assembly; 5. Negative pressure suction chamber; 501. Negative pressure suction port; 502. Negative pressure chamber; 503. Dust removal chamber; 504. Dust collection tray; 505. Guide plate; 6. Partition plate; 7. Differential pressure sensor; 8. Humidity sensor. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0022] Example 1 In daily production, coal washing plants use vibrating screens to classify coal by particle size and then stack coal of different sizes separately. During this process, high-pressure spraying is typically used for dust suppression. This involves atomizing water into fine droplets at a pressure of 3–7 MPa, causing these droplets to collide with and absorb suspended dust particles as they move, thus reducing dust concentration in the work area. To achieve source control, nozzles are deployed along key locations such as the head and tail of the conveyor belt and the material drop point, aiming to suppress dust as soon as it is generated.

[0023] However, significant shortcomings exist in practical use: the atomized water droplets are easily deflected by crosswinds during flight, veering off the preset coverage area, while fine dust particles also escape around the fog screen, greatly reducing the dust suppression effect. Furthermore, in high summer temperatures, the atomized water droplets rapidly evaporate and vaporize before reaching the dust, failing to make contact and adsorb it in time, resulting in a sharp drop in dust suppression efficiency. Overall, existing spray dust suppression devices have poor controllability, and their effectiveness is significantly constrained by ambient airflow and temperature.

[0024] The purpose of this invention is to provide a spray dust suppression device for coal screening, so as to solve the problem that existing spray dust suppression devices are easily affected by the environment.

[0025] A dust suppression spray device for coal screening includes a dust collection hood 1. A front cohesive nozzle assembly 2 is arranged around one end of the dust collection hood 1, such as... Figure 1 As shown, each nozzle in the front cohesive nozzle group 2 is tilted inward, with the spray angle pointing towards the center of the hood, thus forming a converging internal fog curtain. The airflow direction of this fog curtain is converging inward, which can effectively block the crosswind from the outside from flowing back into the hood from the feed inlet, prevent the crosswind from blowing away the fog field inside the hood, and at the same time firmly lock in the original dust generated at the moment of coal impact, preventing it from spreading outward.

[0026] The other end of the dust collector hood 1 is internally surrounded by a discharge nozzle assembly 4. The nozzles in the discharge nozzle assembly 4 have a smaller discharge capacity than those in the front cohesive nozzle assembly 2, and are set to gently push the material at a small angle in the direction of discharge along the coal flow. This position needs to maintain the lowest possible air pressure at all times, slowly guiding the mist-laden airflow towards the bottom of the discharge port to settle, without high-pressure blowing. The purpose of this is to avoid the situation where all nozzles blow in the same direction, causing pressure buildup inside the hood and dust leakage from the discharge port.

[0027] Inside the dust collector hood 1, on both sides, are sets of spray curtain nozzles 3. These nozzles, arranged in two rows on the left and right sides with staggered positions, spray horizontally towards each other, covering the entire width of the screen surface and forming two opposing mist walls. The lateral airflow generated by these two mist walls cancels out the lateral diffusion force, preventing dust from escaping through the gaps in the hood walls. Simultaneously, it forces suspended dust to move slowly towards the center of the screen surface, increasing the probability of dust contact and agglomeration with the mist, thus significantly enhancing the dust removal effect. This area is the main dust removal area of ​​the entire device.

[0028] The top of the dust removal hood 1 is provided with a negative pressure suction chamber 5, which is connected to a negative pressure component. The bottom of the negative pressure suction chamber 5 is provided with a negative pressure suction port 501 that communicates with the inside of the dust removal hood 1, so as to provide a negative pressure environment inside the dust removal hood 1, balance the total air volume sprayed from the three-zone nozzles, and ensure that the air pressure inside the hood is controllable.

[0029] In the above embodiment, when coal enters the bottom of the dust collector hood 1 from the input end of the vibrating screen, a large amount of dust will be generated due to the continuous vibration of the vibrating screen. At this time, the airflow output by the front cohesive nozzle group 2 is drawn inward, which on the one hand prevents the outdoor crosswind from flowing back into the hood from the feed inlet and blowing away the mist field, and on the other hand locks in the original dust generated at the moment of coal impact, preventing it from escaping outward.

[0030] When coal enters the middle area of ​​dust collector hood 1, a large amount of dust is generated during the screening process. At this time, the spray curtain nozzle group 3 plays a major role: the two rows of nozzles on the left and right spray horizontally towards each other, covering the entire width of the screen surface and forming two opposing mist walls. The dust cannot overflow into the gaps in the hood wall and is forced to move slowly towards the center of the screen surface, maximizing the wetting of the dust and preventing most of the dust from continuing to spread with the airflow.

[0031] When the coal leaves the dust collector hood 1, the discharge nozzle group 4 pushes it slightly at a small angle in the direction of coal flow towards the discharge direction, only slowly guiding the airflow containing mist and dust to settle at the bottom of the discharge, avoiding the situation of pressure buildup inside the hood and dust leakage from the discharge port caused by all nozzles blowing in the same direction.

[0032] The negative pressure suction chamber 5 operates in a low-volume, micro-negative-pressure mode, balancing the total air volume emitted from the three nozzles. A micro-negative pressure is maintained inside the hood, preventing the mist from escaping outwards. Simultaneously, it sucks up a small amount of rising ultrafine dust, prolonging the time for dust to remain, collide, and settle within the mist field. Combined with the three-zone gradient airflow, a smooth, low-speed circulating flow field is formed inside the enclosed hood, characterized by "feed gathering → intermediate lateral constraint settling → slow-flow settling at discharge → top micro-extraction." The negative pressure suction chamber 5, working in conjunction with the three nozzle assemblies, achieves a dust removal effect far greater than simply using spray nozzles to spray dust in a targeted manner.

[0033] The top of the dust collector hood 1 needs to maintain a stable air pressure to ensure the controllability of the air pressure at the bottom of the dust collector hood 1. As an optional solution in this embodiment, multiple sets of negative pressure suction ports 501 are provided, with the ports becoming sparser closer to the negative pressure source and denser further away from the negative pressure source. This arrangement aims to maintain a balanced negative pressure difference inside the dust collector hood 1. Actual measurements show that maintaining a slight negative pressure of -5 to -10 Pa inside the dust collector hood 1 is the most effective.

[0034] In addition, a differential pressure sensor 7 and a humidity sensor 8 are installed on the dust collector hood 1. The differential pressure sensor 7 can detect the pressure difference between the inside and outside of the hood in real time, thereby accurately controlling the air pressure and preventing dust inside the dust collector hood 1 from overflowing due to positive pressure. The humidity sensor 8 is used to detect the humidity inside the hood. When the humidity is too high, the water output from the nozzles is too much. The system will adjust the spray speed of the nozzles in the spray curtain nozzle group 3, and at the same time, accelerate the removal of air in a short time by controlling the air pressure to ensure stable humidity and avoid affecting the coal quality.

[0035] The air output from the negative pressure suction chamber 5 contains a small amount of small dust particles, which can be removed before being discharged.

[0036] It should be emphasized that the core improvement of this embodiment lies in addressing the problem of a sharp drop in dust suppression efficiency caused by environmental factors in existing spray dust suppression systems. This embodiment designs a front cohesive nozzle group 2, a counter-spray curtain nozzle group 3, and a discharge nozzle group 4. Each nozzle group is equipped with a water and air delivery pipeline and corresponding nozzles. The front cohesive nozzle group 2 is located at the inlet end, where the airflow is drawn inward to block crosswinds and trap the original dust. The counter-spray curtain nozzle group 3 is located in the middle, with two rows of horizontally opposing sprays forming two opposing mist walls, which laterally constrain the dust to move towards the center, forming the main dust removal area. The discharge nozzle group 4 is equipped with small-volume nozzles that slowly push the dust, avoiding pressure buildup inside the hood and dust leakage. The top negative pressure suction chamber 5 provides a micro-negative pressure of -5 to -10 Pa, making the dust suppression effect no longer dependent on external environmental conditions.

[0037] Example 2 As the coal moves continuously on the vibrating screen, the dry dust on its surface continuously detaches from the coal body. Under the action of the spray curtain nozzle group 3, most of the dust will come into contact with the atomized water droplets and fall due to the increased weight, making it difficult for them to move with the airflow. However, when the left and right rows of nozzles spray horizontally towards each other, some dust will be pushed towards the bottom of the negative pressure suction chamber 5 under the influence of the airflow. Since the negative pressure suction chamber 5 is in a negative pressure state, it is easy for this part of the dust to be directly sucked into the interior, affecting the dust removal effect.

[0038] To solve the above problems, the negative pressure suction chambers 5 are distributed along the top extension direction of the dust collector hood 1, and the negative pressure suction ports 501 are set on both sides of the negative pressure suction chambers 5, such as... Figure 4 As shown, this avoids sending dust directly into the negative pressure suction port 501 when the nozzles are spraying together.

[0039] In this embodiment, although some dust particles will approach the bottom of the negative pressure suction chamber 5 under the influence of the jet stream, more atomized water droplets will also approach this area. The dust particles need to first travel around to both sides of the negative pressure suction chamber 5 before entering the negative pressure suction port 501, thereby increasing the dust particle's travel distance and increasing the possibility of contact between the atomized water droplets and the dust particles, effectively reducing the subsequent dust removal pressure.

[0040] Based on this embodiment, because some dust and atomized water droplets will flow around to both sides of the negative pressure suction chamber 5 under the action of negative pressure, dust will continuously accumulate on the inner walls of the dust collection hoods 1 on both sides of the negative pressure suction chamber 5, forming a moist peat layer to be cleaned. These peat layers will further fix the dust and then lock in moisture, causing the internal humidity to increase, so regular cleaning is required.

[0041] In one optional embodiment, for easier cleaning, the dust cover 1 has side wall inspection ports 101 on both sides, such as... Figure 1 , Figure 2As shown, a side flap 102 is movably provided on the upper side of the side wall inspection port 101. When the side flap 102 is flipped upward, the internal environment of the dust hood 1 can be displayed, and the inner side can be flipped outward, so as to facilitate direct cleaning and maintenance operations inside.

[0042] It should be emphasized that the core improvement of this embodiment lies in addressing the problem in Embodiment 1 where the jet stream directly pushes some dust into the negative pressure suction port 501, increasing the subsequent dust removal pressure. The negative pressure suction port 501 is moved from the bottom to both sides of the negative pressure suction chamber 5. After approaching the bottom of the negative pressure suction chamber 5 under the influence of the jet stream, the dust must first travel around to the sides before entering the negative pressure suction port 501. This increased travel distance raises the probability of contact with atomized water droplets, reducing the burden on subsequent dust removal. Simultaneously, a side wall inspection port 101 and a side flap 102 are added to facilitate the periodic cleaning of the accumulated moist peat layer on the inner walls of both sides of the negative pressure suction chamber 5, preventing the peat layer from solidifying and locking in water, thus ensuring the long-term stable operation of the device.

[0043] Example 3 In Example 2, a small amount of small dust particles will still be output from the output end of the negative pressure suction chamber 5. If they need to be eliminated quickly, other equipment is required, which increases the cost.

[0044] To solve the above problems, such as Figure 5 , Figure 6 As shown, a negative pressure chamber 502 is located at the top of the negative pressure suction chamber 5, and a dust removal chamber 503 is located at the bottom of the negative pressure suction chamber 5. Negative pressure suction ports 501 are located on both sides of the top of the dust removal chamber 503. A guide plate 505, symmetrically fixed between the dust removal chamber 503 and the negative pressure chamber 502, is fixedly arranged. The guide plate 505 is inverted L-shaped and guides the airflow towards the bottom of the dust removal chamber 503. After passing the lower end of the guide plate 505, the airflow enters the negative pressure chamber 502 upwards along the guide plate 505. A dust collection tray 504 is slidably fitted inside the dust removal chamber 503, and dust falls onto the dust collection tray 504 under gravity.

[0045] In this embodiment, after a period of use, the surfaces of the dust collection plate 504 and the guide plate 505 become wet, making it easier for dust to adhere. When the airflow carrying dust and atomized water droplets enters the dust collection chamber 503 through the side wall inspection port 101, the dust movement slows down, making it more susceptible to gravity or inertia. It comes into contact with the surfaces of the dust collection plate 504 and the guide plate 505, or with the atomized water droplets, increasing its weight and causing it to fall onto the dust collection plate 504. A guide channel is formed between the two sets of guide plates 505. The airflow carrying dust and atomized water droplets moves upwards along the bottom of the guide channel. During this process, the speed of the dust particles is less than the speed of the atomized water droplets, making it easier for them to combine with the droplets, increasing their weight and causing them to fall onto the dust collection plate 504, thereby reducing the amount of dust in the output air.

[0046] It should be emphasized that the core improvement of this embodiment lies in the addition of a two-stage separation structure inside the negative pressure suction chamber 5, consisting of a dust collection chamber 503, a guide plate 505, and a dust collection tray 504. The surfaces of the dust collection tray 504 and the guide plate 505 become wet after a period of use, making it easier for dust to adhere. The airflow is guided to the bottom by the inverted L-shaped guide plate 505 and then rises along the guide channel. Because the dust's movement speed is less than that of water droplets, it is more likely to combine with water droplets or impact the wet surfaces of the guide plate 505 and the dust collection tray 504, settling and being collected under gravity. This eliminates the need for additional cyclone separators or bag filters, directly intercepting and collecting dust within the chamber, reducing equipment costs and system complexity.

[0047] In Embodiment 1, the airflow output from the negative pressure suction chamber 5 contains some small dust particles. In an optional embodiment, the negative pressure suction chamber 5 is connected to a cyclone separator, and a bag filter is installed at the air outlet of the cyclone separator. The air outlet of the bag filter is connected to a negative pressure fan. Large dust particles undergo preliminary separation by the cyclone separator, while small dust particles undergo fine dust removal by the bag filter. Finally, the required negative pressure is output through the fan.

[0048] In embodiments two, three, and four, the dust removal effect inside the dust collector hood 1 is easily affected by the airflow moving in the lateral direction of the dust collector hood 1, causing dust to leave the dust collector hood 1 and affecting the working environment. In another optional solution, baffles 6 are fixedly installed at equal intervals at the bottom inside the dust collector hood 1, and the baffles 6 are used to weaken the impact of the lateral airflow on the dust removal effect.

[0049] In another alternative, a nozzle protective cover 301 is fixedly installed on the nozzles in the spray curtain nozzle assembly 3 to prevent coal from hitting the nozzles and to protect the nozzles near the coal from damage.

[0050] Working principle: During operation, coal enters the bottom of the dust collector hood 1 from the input end of the vibrating screen. The continuous vibration of the vibrating screen generates a large amount of dust, and the impact of falling coal instantly generates primary dust. At this time, the front cohesive nozzle group 2 sprays inward at an angle, and the airflow converges towards the center of the hood, forming a convergent internal fog curtain. On the one hand, this prevents the crosswind from the outside from flowing back into the hood from the feed inlet and dispersing the fog field; on the other hand, it firmly locks in the primary dust generated by the impact of falling coal, preventing it from escaping outward.

[0051] After coal enters the middle area of ​​dust collector hood 1, the screening process generates a large amount of dust. Two rows of nozzles in the spray curtain nozzle group 3 spray horizontally towards each other, covering the entire width of the screen surface and forming two opposing mist walls. The lateral airflow generated by the two mist walls cancels out the lateral diffusion force, preventing dust from escaping through the gaps in the hood walls. Instead, the dust is forced to move slowly towards the center of the screen surface, increasing the probability of dust contact and agglomeration with the mist, maximizing dust wetting, and preventing most dust from continuing to diffuse with the airflow. This area is the main dust collection area.

[0052] When the coal leaves the dust collector hood 1, the discharge nozzle group 4 pushes it slightly in the direction of discharge with a small displacement and small angle along the coal flow, always maintaining the lowest air pressure at this position, and only slowly guiding the airflow containing mist and dust to settle at the bottom of the discharge, without high pressure blowing, to avoid the pressure buildup inside the hood and dust leakage from the discharge port caused by all nozzles blowing in the same direction.

[0053] Throughout the process, the top negative pressure suction chamber 5 operates in a low-volume, micro-negative-pressure mode, balancing the total air volume ejected from the three-zone nozzles, maintaining a micro-negative pressure of -5 to -10 Pa inside the hood. The differential pressure sensor 7 monitors the pressure difference between the inside and outside of the hood in real time and precisely controls the air pressure to prevent dust overflow caused by internal positive pressure. The humidity sensor 8 detects the humidity inside the hood; if the humidity is too high, it adjusts the nozzle spray speed and briefly accelerates the suction to ensure stable humidity. The negative pressure suction chamber 5 sucks up a small amount of floating ultrafine dust, prolonging the time for dust to remain, collide, and settle within the mist field. The three-zone gradient airflow works together to form a smooth, low-speed circulating flow field within the enclosed hood, characterized by "feed collection → intermediate lateral constraint settling → slow flow settling at the outlet → top micro-extraction."

[0054] When the jet stream pushes some dust towards the bottom of the negative pressure suction chamber 5, the dust must first travel around to both sides of the negative pressure suction chamber 5 before entering through the negative pressure suction port 501. This increases the travel distance and the probability of contact with atomized water droplets. The airflow entering the negative pressure suction chamber 5 is guided to the bottom by the inverted L-shaped guide plate 505 and then rises along the guide channel. Because the dust moves at a lower speed than the water droplets, it is easier for the dust to combine with the water droplets or impact the wet surface of the guide plate 505 and the dust collection tray 504. Under the action of gravity, the dust settles and is collected, reducing the amount of dust in the output air.

[0055] The moist peat layer accumulated on both sides of the inner wall of the negative pressure suction chamber 5 is cleaned regularly through the side wall inspection port 101 and the side flap 102 to prevent the peat layer from solidifying and locking in water, which would cause the internal humidity to rise continuously and ensure the long-term stable operation of the device.

[0056] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed application.

Claims

1. A spray dust suppression device for coal screening, comprising a dust collection hood (1), characterized in that: The dust collector hood (1) is surrounded by a front cohesive nozzle group (2) at one end. The nozzles in the front cohesive nozzle group (2) are tilted inward and the spray angle is directed toward the center of the hood, forming a convergent cohesive fog curtain to lock in the original dust generated by the impact of falling coal. The dust collector hood (1) is surrounded by a discharge nozzle group (4) at the other end. The nozzles in the discharge nozzle group (4) are tilted outward and gently pushed outward in the direction of coal flow, slowly guiding the mist-dust-containing airflow to settle at the bottom of the discharge. The dust removal hood (1) is equipped with spray curtain nozzle groups (3) on both sides inside. The spray curtain nozzle groups (3) are equipped with two rows of nozzles on the left and right sides, spraying horizontally towards each other and covering the entire width of the screen surface to form two opposing mist walls, forcing the suspended dust to move slowly towards the center of the screen surface. The dust hood (1) is provided with a negative pressure suction chamber (5) at the top. The negative pressure suction chamber (5) is connected to a negative pressure component. The bottom of the negative pressure suction chamber (5) is provided with a negative pressure suction port (501) that communicates with the inside of the dust hood (1) to provide a negative pressure environment inside the dust hood (1) and balance the total air volume sprayed from the three-zone nozzles.

2. The spray dust suppression device for coal screening as described in claim 1, characterized in that, The negative pressure suction port (501) is provided in multiple sets, and the closer to the negative pressure source, the sparser it is, and the farther away from the negative pressure source, the denser it is, so as to maintain a balanced negative pressure difference inside the dust removal hood (1).

3. The spray dust suppression device for coal screening as described in claim 2, characterized in that, The negative pressure suction chamber (5) is distributed along the top extension direction of the dust removal hood (1), and the negative pressure suction port (501) is set on both sides of the negative pressure suction chamber (5) to avoid the nozzles spraying directly into the negative pressure suction port (501).

4. A spray dust suppression device for coal screening as described in claim 1, 2, or 3, characterized in that, The dust collector hood (1) has side wall inspection ports (101) on both sides. A side flap (102) is movably provided on the upper side of the side wall inspection port (101). The side flap (102) can be flipped up to show the internal environment of the dust collector hood (1).

5. A spray dust suppression device for coal screening as described in claim 4, characterized in that, The dust cover (1) is equipped with a differential pressure sensor (7) and a humidity sensor (8).

6. The spray dust suppression device for coal screening as described in claim 5, characterized in that, The negative pressure suction chamber (5) is provided with a negative pressure chamber (502) at the top and a dust removal chamber (503) at the bottom. The negative pressure suction port (501) is located on both sides of the top of the dust removal chamber (503). A guide plate (505) is provided between the dust removal chamber (503) and the negative pressure chamber (502). The guide plate (505) guides the airflow to the bottom of the dust removal chamber (503). After the airflow passes the lower end of the guide plate (505), it enters the negative pressure chamber (502) upward along the guide plate (505). A dust collection tray (504) is slidably fitted inside the dust removal chamber (503). Dust falls onto the dust collection tray (504) under the action of gravity.

7. A spray dust suppression device for coal screening as described in claim 4, characterized in that, The dust collector hood (1) has partitions (6) fixedly installed at equal intervals at the bottom.

8. A spray dust suppression device for coal screening as described in claim 7, characterized in that, The nozzles in the spray curtain nozzle group (3) are fixedly equipped with nozzle protective covers (301) to prevent coal from impacting them.

9. A spray dust suppression device for coal screening as described in claim 1, characterized in that, The negative pressure suction chamber (5) is connected to a cyclone separator, the air supply end of the cyclone separator is connected to a bag filter, and the air supply end of the bag filter is connected to a negative pressure fan.

10. A spray dust suppression device for coal screening as described in claim 5, characterized in that, The dust removal hood (1) maintains a slight negative pressure of -5 to -10 Pa.

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