A process for controlling the fineness of a single coal

Abstract

The present application relates to coking technical field, especially be a kind of fineness control process of single coal, the process includes incoming material conveyor, first communicating chute, first stage belt feeder, second communicating chute, first stage pulverizer, third communicating chute, first stage sampler, second stage belt feeder, tail chute, head chute, second stage pulverizer, fourth communicating chute, second stage sampler and discharge conveyor;The process proposed by the present application compared with traditional coking coal preparation process, pre-pulverizer room and pulverizer room are combined into one, set two stage pulverizer room before coal blending unit, simplify traditional coal preparation process, shorten the process, make production management more centralized, only set a pulverizer room before coal blending, save the corridor before the second seat pulverizer room in conventional process, significantly reduce the initial investment cost, reduce the explosion danger zone of coal preparation system at the same time, improve the safety of production.

Description

Technical Field

[0001] This invention relates to the field of coking technology, specifically to a process for controlling the fineness of a single type of coal. Background Technology

[0002] In coking coal preparation processes, fineness control of different coal types is a key factor affecting coke quality. In traditional processes, different coal types have different fineness requirements due to their different physicochemical properties. Hard coal types usually require two grinding processes to achieve the required fineness, while non-hard coal types can achieve the required fineness with a single grinding process.

[0003] For coal blending schemes with significant differences in coal hardness, the following two process flows are typically used in coking coal preparation to control the fineness of the blended coal entering the furnace.

[0004] 1. Selective pre-crushing process: This process involves selectively pre-crushing the individual coals that make up the coking coal according to their different properties, and then mixing and crushing them in a specified ratio.

[0005] 2. Group pre-crushing process: This process divides the individual coals that make up the coking coal into two groups, hard coal and non-hard coal, according to their differences in hardness. After being mixed in a specified ratio, the hard coal is pre-crushed and then combined with the non-hard coal for further crushing.

[0006] Both of the aforementioned processes require two process units: a pre-crushing chamber and a crushing chamber. This arrangement results in complex processes, long flow rates, high investment costs, and multiple explosion-hazardous areas. Furthermore, both processes involve a second crushing of mixed coal types, making precise control over the fineness of each individual coal type impossible. Summary of the Invention

[0007] The purpose of this invention is to provide a fineness control process for a single type of coal, achieving precise control over the fineness of each individual type of coal. This invention simplifies the traditional coking coal preparation process, shortens the process flow, reduces investment, and reduces the explosion hazard zone, while improving the accuracy of fineness control of the coal entering the coking furnace, which is beneficial for precise coal blending.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a fineness control process for a single type of coal, comprising an incoming conveyor, a first connecting chute, a primary belt feeder, a second connecting chute, a primary crusher, a third connecting chute, a primary sampler, a secondary belt feeder, a tail chute, a head chute, a secondary crusher, a fourth connecting chute, a secondary sampler, and an outgoing conveyor. The incoming conveyor, the first connecting chute, the primary belt feeder, and the second connecting chute constitute the feeding system for the primary crusher, and this feeding system is located above the primary crusher. The third connecting chute, the secondary belt feeder, and the head chute constitute the system for supplying material to the secondary crusher, and are located above the secondary crusher. The primary sampler and the secondary sampler are respectively located at the discharge ports of the primary and secondary crushers. The bottoms of the primary and secondary belt feeders are each equipped with a self-cleaning mechanism.

[0009] Preferably, the width of the primary belt feeder and the secondary belt feeder are matched with the feed inlets of the primary crusher and the secondary crusher, and the primary belt feeder and the secondary belt feeder are equipped with a material leveling device to spread the material evenly.

[0010] Preferably, the incoming and outgoing conveyors are belt conveyors, scraper conveyors, vibrating conveyors, chain conveyors, or screw conveyors.

[0011] Preferably, the self-cleaning mechanism includes: The movable seat is located below the belt feeder; Two sets of vertical plates are attached to both sides of the bottom of the belt feeder. The crankshaft is rotatably connected to the surface of the vertical plate and is connected to the drive roller shaft of the belt feeder via belt drive. The movable column is connected to the crankshaft via a connecting rod, and the two ends of the connecting rod are respectively hinged to the movable column and the crankshaft. A sliding assembly is used to support the movable column and the movable seat for sliding. An electric cylinder is bolted to the top of the movable seat; The brush plate is bolted to the output shaft of the electric cylinder, and dust collection covers are bolted to both sides of the brush plate. The dust collection component, used in conjunction with the dust collection hood, adsorbs the dust generated during cleaning; A collection component is used to collect the dust adsorbed by the dust collection component.

[0012] Preferably, the sliding assembly includes a first connecting rod, a slider, a slide rail, a second connecting rod, and a sliding sleeve. The first connecting rod fixes the slider to the movable seat, the slider is slidably connected to the surface of the slide rail, the second connecting rod is bolted to the bottom of the belt feeder, the sliding sleeve is bolted to the other end of the second connecting rod, and the movable column is slidably connected to the inner wall of the sliding sleeve.

[0013] Preferably, the dust collection assembly includes a fixed rod, a movable rod, and a housing. The fixed rod is bolted to the belt feeder, and the movable rod is bolted to the fixed rod. The other end of the movable rod extends into the interior of the housing and is bolted with a piston. A first box and a second box are respectively connected to both sides of the surface of the housing. A first one-way door and a second one-way door are respectively provided inside the first box and the second box. A flexible hose is connected to the surface of the first box, and the other end of the flexible hose is connected to the dust collection hood. A connecting pipe is connected to the second box.

[0014] Preferably, the first one-way door can only be opened to the inside of the enclosure, and the second one-way door can only be opened to the outside of the enclosure.

[0015] Preferably, the collection assembly includes a storage box, a barrier net, a box cover, and an air outlet pipe. The other end of the connecting pipe is connected to the storage box. The barrier net is bolted to the inside of the box. The box cover is bolted to the side of the storage box. The air outlet pipe is connected to the storage box.

[0016] Preferably, the outlet end of the air duct is aligned with the bottom of the belt feeder.

[0017] A process for controlling the fineness of a single type of coal, characterized by the following steps: Step 1: The incoming material enters the material layer of the two-stage crusher chamber via the material conveyor, and then enters the first-stage belt feeder in the lower layer through the first connecting chute; Step 2: After the material is leveled by the leveling device on the primary belt feeder, it enters the primary crusher through the second connecting chute for the first crushing. The crushed coal then enters the secondary belt feeder in the lower layer through the third connecting chute. Step 3: The material can be directly fed into the lower discharge conveyor through the tail chute on the secondary belt feeder and sent out of the two-stage crushing chamber; or it can be flattened by the leveling device and then fed into the secondary crusher through the head chute for a second crushing. The material after the second crushing is fed into the lower discharge conveyor through the fourth connecting chute and sent out of the two-stage crushing chamber. Step 4: Install a sampler at the feed inlet of each stage of the crusher to take samples of the crushed material. Adjust the crushing effect of the crusher by inspecting the fineness of the samples.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Compared with the traditional coking coal preparation process, the process proposed in this invention combines the pre-crushing chamber and the crushing chamber into one, setting up two-stage crushing chambers before the coal blending unit. This simplifies the traditional coal preparation process, shortens the process flow, and makes production management more centralized. Only one crushing chamber is set up before coal blending, eliminating the corridor in front of the second crushing chamber in the conventional process, significantly reducing the initial investment cost. At the same time, it reduces the explosion hazard area of ​​the coal preparation system, improves production safety, and achieves precise control of the fineness of single coal types by performing two-stage crushing for hard coal types and selectively performing one-stage crushing for non-hard coal types. This is conducive to coking plants to achieve precise coal blending and achieve the goal of cost reduction and efficiency improvement.

[0019] 2. This invention utilizes a self-cleaning mechanism located below the belt feeder. Through the linkage design of its movable seat and crankshaft, the brush plate continuously cleans the return belt surface of the primary or secondary belt feeder during the reciprocating motion driven by the active roller. This removes dry coal powder adsorbed by electrostatics, wet coal slurry, and residual coal ash trapped on the aged and rough surface of the belt, thus preventing cross-contamination of different coal types during belt conveying and ensuring the accuracy of subsequent sampling fineness test results.

[0020] 3. When the movable seat drives the box to reciprocate, the piston remains relatively stationary with the movable rod through the fixed rod, causing the volume of the inner cavity of the box to change periodically. Combined with the one-way conduction characteristic that the first one-way door opens only into the box and the second one-way door opens only outward, the dust-laden air captured by the dust hood and hose is continuously drawn into the box and compressed into the storage box. The coal dust is effectively trapped in the storage box by the blocking net, while the separated clean airflow is blown back onto the belt surface through the air outlet pipe, forming an auxiliary blowing airflow, which further enhances the removal effect of residual micro-dust on the belt surface. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the equipment used in the process of this invention; Figure 2 This is a schematic diagram of the equipment used in the process of this invention from another side view; Figure 3 This is a schematic diagram of the self-cleaning mechanism in this invention on a belt feeder; Figure 4 This is a bottom view of the self-cleaning mechanism of the present invention on a belt feeder; Figure 5 This is a schematic diagram of the self-cleaning mechanism in this invention; Figure 6 This is a schematic diagram of the structure of the brush plate and its surface in this invention; Figure 7 This is a partial structural diagram of the self-cleaning mechanism in this invention; Figure 8 This is a schematic diagram of the dust collection component in this invention; Figure 9 This is a cross-sectional view of the box body, the first box body, and the second box body in this invention; Figure 10 This is a schematic diagram of the storage box after the lid has been removed in this invention.

[0022] In the diagram: 1. Incoming material conveyor; 2. First connecting chute; 3. Primary belt feeder; 4. Second connecting chute; 5. Primary crusher; 6. Third connecting chute; 7. Primary sampler; 8. Secondary belt feeder; 9. Tail chute; 10. Head chute; 11. Secondary crusher; 12. Fourth connecting chute; 13. Secondary sampler; 14. Discharge conveyor; 15. Self-cleaning mechanism; 151. Movable seat; 152. Crankshaft; 153. Vertical plate; 154. Movable column; 155. Dust collection assembly; 1551. Fixed rod; 1552. Movable rod; 155 3. Box body; 1554. First box body; 1555. Hose; 1556. Piston; 1557. Second box body; 1558. Connecting pipe; 1559. First one-way door; 1559a. Second one-way door; 156. Collection assembly; 1561. Storage box; 1562. Barrier net; 1563. Box cover; 1564. Air outlet pipe; 157. Electric cylinder; 158. Brush plate; 1581. Dust hood; 159. Sliding assembly; 1591. First connecting rod; 1592. Slider; 1593. Slide rail; 1594. Second connecting rod; 1595. Sliding sleeve. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1-10As shown, a fineness control process for a single type of coal includes an inlet conveyor 1, a first connecting chute 2, a primary belt feeder 3, a second connecting chute 4, a primary crusher 5, a third connecting chute 6, a primary sampler 7, a secondary belt feeder 8, a tail chute 9, a head chute 10, a secondary crusher 11, a fourth connecting chute 12, a secondary sampler 13, and an outlet conveyor 14. The inlet conveyor 1, first connecting chute 2, primary belt feeder 3, and second connecting chute 4 form the feeding system for the primary crusher 5, positioned above it. The third connecting chute 6, secondary belt feeder 8, and head chute 10 form the feeding system for the secondary crusher 11, positioned above it. The primary sampler 7 and secondary sampler 13 are respectively located at the discharge ports of the primary crusher 5 and the secondary crusher 11 to sample the crushed material. The outlet conveyor 14 is located below the crushers to deliver the crushed material.

[0025] The main body of the entire process equipment is located in a two-stage crusher room, which facilitates centralized management and control. The width of the primary belt feeder 3 and the secondary belt feeder 8 is matched with the feed inlet of the crusher. The belt feeders are equipped with a leveling device to spread the incoming material evenly and improve the crushing effect. The design of the leveling device allows the material to enter the crusher evenly, avoids local overload, and improves the crushing efficiency. The secondary belt feeder 8 can convey materials in both directions, allowing different types of coal to selectively enter the secondary crusher 11. This bidirectional conveying design increases the flexibility of the process and allows for the selection of whether to perform secondary crushing based on the characteristics of different types of coal.

[0026] The primary sampler 7 and the secondary sampler 13 sample the coal from the discharge ports of the primary crusher 5 and the secondary crusher 11, respectively. The samples collected by the samplers can be used to analyze the fineness of the coal and provide a basis for process adjustment.

[0027] The incoming material conveyor (1) and outgoing material conveyor (14) include belt conveyors, scraper conveyors, vibrating conveyors, chain conveyors, or screw conveyors. The appropriate conveyor type can be selected based on the actual working conditions to improve conveying efficiency.

[0028] The fineness control process for this single type of coal is set before the coal blending unit in the coal preparation process, so as to provide coal with uniform particle size for subsequent coal blending processes and improve the quality of coal blending.

[0029] The fineness control process for this single type of coal includes the following steps: Step 1: The incoming material enters the material layer of the two-stage crusher chamber through the material conveyor 1, and then enters the lower-level primary belt feeder 3 through the first connecting chute 2; Step 2: After being leveled by the leveling device on the primary belt feeder 3, the material enters the primary crusher 5 through the second connecting chute 4 for the first crushing. The crushed coal enters the secondary belt feeder 8 through the third connecting chute 6. Step 3: The material can be directly fed into the lower discharge conveyor 14 through the tail chute 9 on the secondary belt feeder 8 and sent out of the two-stage crushing chamber; or it can be flattened by the leveling device and then fed into the secondary crusher 11 through the head chute 10 for a second crushing. The material after the second crushing is fed into the lower discharge conveyor 14 through the fourth connecting chute 12 and sent out of the two-stage crushing chamber. Step 4: Install a sampler at the feed inlet of each stage of the crusher to take samples of the crushed material. By inspecting the fineness of the samples, adjust the crushing effect of the crusher to achieve accurate control of the fineness of a single type of coal.

[0030] In practical applications, when finer particle size is required for the coal, two-stage crushing can be chosen; when only one-stage crushing is needed, the material can pass through only the primary crusher 5 and then be directly conveyed to the discharge conveyor 14 via the secondary belt feeder 8. The sample analysis results obtained through the sampler allow for timely adjustment of the crusher's operating parameters, such as speed and gap, to achieve the desired crushing effect.

[0031] The advantage of this process is that it can flexibly adjust the degree of crushing according to the characteristics of different coal types and the requirements of subsequent processes for coal fineness, so as to achieve precise control of the fineness of a single type of coal, provide stable quality raw materials for the coal blending process, and improve overall production efficiency and product quality.

[0032] During the coal preparation and conveying process, the primary belt feeder 3 and the secondary belt feeder 8 may experience coal ash adhesion due to electrostatic adsorption of dry coal powder, moisture adhesion of wet coal slurry, or surface aging and roughness. This residual coal ash mixes with the next batch of different coal types as the belt moves, causing cross-contamination of individual coal types. This directly interferes with the accuracy of subsequent sampling fineness testing, thus undermining the precise coal blending control target pursued by the process. Therefore, a self-cleaning mechanism 15 is installed below the belt feeder. The self-cleaning mechanism 15 includes a movable seat 151, a vertical plate 153, a crankshaft 152, a movable column 154, a sliding assembly 159, an electric cylinder 157, a brush plate 158, a dust collection assembly 155, and a collection assembly 156. The movable seat 151 is located below the belt feeder. Two sets of vertical plates 153 are respectively bolted to both sides of the bottom of the belt feeder. The crankshaft 152 and the vertical plate 159... The surface of the 3 is rotatably connected and connected to the drive roller shaft of the belt feeder via belt drive. The movable column 154 and the crankshaft 152 are connected to each other via connecting rods, and the two ends of the connecting rods are respectively hinged to the movable column 154 and the crankshaft 152. The sliding assembly 159 is used to support the movable column 154 and the movable seat 151 for sliding. The electric cylinder 157 is bolted to the top of the movable seat 151. The brush plate 158 is bolted to the output shaft of the electric cylinder 157. Dust suction hoods 1581 are bolted to both sides of the brush plate 158. The dust suction assembly 155 works in conjunction with the dust suction hoods 1581 to adsorb the dust generated during cleaning. The collection assembly 156 is used to collect the dust adsorbed by the dust suction assembly 155.

[0033] The sliding assembly 159 includes a first connecting rod 1591, a slider 1592, a slide rail 1593, a second connecting rod 1594, and a sliding sleeve 1595. The first connecting rod 1591 fixes the slider 1592 to the movable seat 151. The slider 1592 is slidably connected to the surface of the slide rail 1593. The second connecting rod 1594 is bolted to the bottom of the belt feeder. The sliding sleeve 1595 is bolted to the other end of the second connecting rod 1594. The movable column 154 is slidably connected to the inner wall of the sliding sleeve 1595. The movable column 154 can drive the slider 1592 to slide along the surface of the slide rail 1593, increasing the stability of the movement. The movable column 154 can slide along the inner wall of the sliding sleeve 1595, thus being supported and not easily bent.

[0034] During operation, the primary belt feeder 3 or the secondary belt feeder 8 runs, and its drive roller is connected by belt drive to drive the crankshaft 152 to rotate, and drive the movable column 154 to slide back and forth along the inner wall of the sliding sleeve 1595. At the same time, it drives the movable seat 151 to move back and forth. At this time, the electric cylinder 157 is activated to extend its output shaft, so that the brush plate 158 is attached to the surface of the primary belt feeder 3 or the secondary belt feeder 8 to clean the coal ash adhering to the surface.

[0035] However, dust is generated during the cleaning process, so a dust collection component 155 and a collection component 156 are provided. The dust collection component 155 includes a fixed rod 1551, a movable rod 1552, and a housing 1553. The fixed rod 1551 is bolted to the belt feeder, and the movable rod 1552 is bolted to the fixed rod 1551. The other end of the movable rod 1552 extends into the interior of the housing 1553 and is bolted with a piston 1556. A first box 1554 and a second box 1557 are respectively connected to both sides of the surface of the housing 1553. A first one-way door 1559 and a second one-way door 1559a are respectively provided inside the first box 1554 and the second box 1557. A flexible hose 1555 is connected to the surface of the first box 1554. The other end of the hose 1555 is connected to the dust hood 1581. The second box 1557 is connected to the connecting pipe 1558. The first one-way door 1559 can only be opened to the inside of the box 1553, and the second one-way door 1559a can only be opened to the outside of the box 1553. The collection component 156 includes a storage box 1561, a barrier net 1562, a box cover 1563, and an air outlet pipe 1564. The other end of the connecting pipe 1558 is connected to the storage box 1561. The barrier net 1562 is bolted to the inside of the box 1553. The box cover 1563 is bolted to the side of the storage box 1561. The air outlet pipe 1564 is connected to the storage box 1561, and the outlet end of the air outlet pipe 1564 is aligned with the bottom of the belt feeder.

[0036] During the movement of the movable seat 151, it drives the housing 1553 to move together. Since the fixed rod 1551 and the movable rod 1552 are fixed to the belt feeder, the piston 1556 is also fixed. Therefore, the piston 1556 moves relative to the inside of the housing 1553, causing the volume of the side of the housing 1553 away from the movable rod 1552 to sometimes increase and sometimes decrease. When the volume increases, the internal pressure decreases, allowing external air and coal ash to pass through the dust suction hood 1581, hose 1555, first housing 1554, and first one-way door 1559. The first one-way door 1559 opens inwards, while the second one-way door 1559a closes, allowing air and coal ash to temporarily enter the interior of the housing 1553. As the volume decreases, the coal ash and air cause the second one-way door 1559a to open outwards, while the first one-way door 1559 closes. The second one-way door 1559a then opens, allowing air and coal ash to enter the interior of the storage tank 1561 through the connecting pipe 1558. The coal ash is intercepted by the barrier net 1562, and the air is blown onto the surface of the belt feeder through the exhaust pipe 1564, achieving further cleaning and thus realizing the adsorption and collection of coal ash. After the equipment is shut down, opening the housing cover 1563 allows the coal dust accumulated inside the storage tank 1561 to be cleaned out.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for controlling the fineness of a single type of coal, characterized in that: The process includes an inlet conveyor (1), a first connecting chute (2), a primary belt feeder (3), a second connecting chute (4), a primary crusher (5), a third connecting chute (6), a primary sampler (7), a secondary belt feeder (8), a tail chute (9), a head chute (10), a secondary crusher (11), a fourth connecting chute (12), a secondary sampler (13), and an outlet conveyor (14). The inlet conveyor (1), the first connecting chute (2), the primary belt feeder (3), and the second connecting chute (4) constitute the primary crusher. The feeding system of the crusher (5) is located above the primary crusher (5). The third connecting chute (6), the secondary belt feeder (8), and the head chute (10) form a feeding system for the secondary crusher (11) and are located above the secondary crusher (11). The primary sampler (7) and the secondary sampler (13) are respectively located at the discharge ports of the primary crusher (5) and the secondary crusher (11). The bottom of the primary belt feeder (3) and the secondary belt feeder (8) are both equipped with a self-cleaning mechanism (15).

2. The fineness control process for a single type of coal according to claim 1, characterized in that: The width of the primary belt feeder (3) and the secondary belt feeder (8) are matched with the feed inlets of the primary crusher (5) and the secondary crusher (11). The primary belt feeder (3) and the secondary belt feeder (8) are equipped with a material leveling device to spread the material flat.

3. The fineness control process for a single type of coal according to claim 1, characterized in that: The incoming material conveyor (1) and the outgoing material conveyor (14) are selected from belt conveyors, scraper conveyors, vibrating conveyors, chain conveyors or screw conveyors.

4. The fineness control process for a single type of coal according to claim 1, characterized in that, The self-cleaning mechanism (15) includes: The movable seat (151) is located below the belt feeder; Vertical plates (153), in two sets, are respectively bolted to both sides of the bottom of the belt feeder; The crankshaft (152) is rotatably connected to the surface of the vertical plate (153) and is connected to the drive roller shaft of the belt feeder via belt drive; The movable column (154) is connected to the crankshaft (152) via a connecting rod, and the two ends of the connecting rod are respectively hinged to the movable column (154) and the crankshaft (152); A sliding assembly (159) is used to support the movable column (154) and the movable seat (151) for sliding. An electric cylinder (157) is bolted to the top of the movable seat (151); The brush plate (158) is bolted to the output shaft of the electric cylinder (157), and dust collection covers (1581) are bolted to both sides of the brush plate (158). The dust collection component (155) is used in conjunction with the dust collection hood (1581) to adsorb the dust generated during cleaning; A collection component (156) is used to collect the dust adsorbed by the dust collection component (155).

5. The fineness control process for a single type of coal according to claim 4, characterized in that: The sliding assembly (159) includes a first connecting rod (1591), a slider (1592), a slide rail (1593), a second connecting rod (1594), and a sliding sleeve (1595). The first connecting rod (1591) fixes the slider (1592) to the movable seat (151). The slider (1592) is slidably connected to the surface of the slide rail (1593). The second connecting rod (1594) is bolted to the bottom of the belt feeder. The sliding sleeve (1595) is bolted to the other end of the second connecting rod (1594). The movable column (154) is slidably connected to the inner wall of the sliding sleeve (1595).

6. The fineness control process for a single type of coal according to claim 4, characterized in that: The dust collection assembly (155) includes a fixed rod (1551), a movable rod (1552), and a housing (1553). The fixed rod (1551) is bolted to the belt feeder, and the movable rod (1552) is bolted to the fixed rod (1551). The other end of the movable rod (1552) extends into the interior of the housing (1553) and is bolted with a piston (1556). First boxes are respectively connected to both sides of the surface of the housing (1553). The first box (1554) and the second box (1557) are respectively provided with a first one-way door (1559) and a second one-way door (1559a). A flexible hose (1555) is provided on the surface of the first box (1554), and the other end of the flexible hose (1555) is connected to the dust hood (1581). A connecting pipe (1558) is provided on the second box (1557).

7. The fineness control process for a single type of coal according to claim 6, characterized in that: The first one-way door (1559) can only be opened to the inside of the housing (1553), and the second one-way door (1559a) can only be opened to the outside of the housing (1553).

8. The fineness control process for a single type of coal according to claim 6, characterized in that: The collection assembly (156) includes a storage box (1561), a barrier net (1562), a box cover (1563), and an air outlet pipe (1564). The other end of the connecting pipe (1558) is connected to the storage box (1561). The barrier net (1562) is bolted to the inside of the box body (1553). The box cover (1563) is bolted to the side of the storage box (1561). The air outlet pipe (1564) is connected to the storage box (1561).

9. The fineness control process for a single type of coal according to claim 8, characterized in that: The outlet end of the air duct (1564) is aligned with the bottom of the belt feeder.

10. The fineness control process for a single type of coal according to claim 1, characterized in that: The process includes the following steps: Step 1: The incoming material enters the material layer of the two-stage crusher chamber through the material conveyor (1), and enters the first-stage belt feeder (3) of the lower layer through the first connecting chute (2); Step 2: After the material is flattened by the leveling device on the primary belt feeder (3), it enters the primary crusher (5) through the second connecting chute (4) for the first crushing. The crushed coal enters the secondary belt feeder (8) in the lower layer through the third connecting chute (6). Step 3: The material can be directly fed into the lower discharge conveyor (14) through the tail chute (9) on the secondary belt feeder (8) and sent out of the two-stage crusher chamber; or it can be flattened by the leveling device and fed into the secondary crusher (11) through the head chute (10) for a second crushing. The material after the second crushing is fed into the lower discharge conveyor (14) through the fourth connecting chute (12) and sent out of the two-stage crusher chamber. Step 4: Install a sampler at the feed inlet of each stage of the crusher to take samples of the crushed material. Adjust the crushing effect of the crusher by inspecting the fineness of the samples.

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