Dry separation system with middling coal recleaning function

Abstract

The invention provides a dry separation system with a middling coal re-separation function, which comprises a first-section separation unit, a second-section separation unit and a third-section separation unit, the first-section separation unit comprises a first-section separation bed, a first-section air inlet device and a first-section vibration motor, the first-section vibration motor is used for driving the first-section separation bed to vibrate, and the first-section air inlet device is positioned below the first-section separation bed; the second-section sorting unit comprises a second-section sorting bed, a second-section air inlet device and a second-section vibration motor used for driving the second-section sorting bed to vibrate, and the second-section air inlet device is located below the second-section sorting bed; the inlet end of the middling coal product chute is used for being connected with a middling coal outlet of the discharging end of the first-section separation bed, and the outlet end of the middling coal product chute leads to the second-section separation bed. Efficient re-separation of middling coal is achieved through structural integration and innovation of the two sections of separation beds, equipment arrangement is simplified, and production efficiency and separation precision are improved.

Description

Technical Field

[0001] This invention relates to the field of coal sorting technology, and in particular to a dry sorting system with middlings re-sorting function. Background Technology

[0002] Coal preparation (also known as coal washing) is the process of removing impurities (such as ash, sulfur, and gangue) from raw coal using physical or chemical methods, and processing it into coal products of different qualities according to quality and specifications. Clean coal, middlings, and gangue are different products generated during coal washing and processing, distinguished by their quality, uses, and composition. Clean coal is a high-quality coal product obtained after washing and removing impurities such as gangue from raw coal; it has low ash content and high calorific value. Gangue is solid waste discharged during coal mining and washing, mainly consisting of rocks interbedded in coal seams, with low carbon content (approximately 20%–30%) and is not easily combustible. Middlings is an intermediate product generated during coal separation, with a density between that of clean coal and gangue. Coal preparation processes are mainly divided into two categories: wet separation and dry separation. However, wet separation processes consume large amounts of water resources and require the construction of a coal slurry water treatment system, resulting in high investment costs, long construction periods, and complex operation and maintenance. In the arid and water-scarce regions of Northwest my country, the scarcity of water resources severely restricts the promotion and application of wet coal preparation technology. At the same time, for low-rank coal that is prone to mudification, the treatment of coal slurry water is difficult and the cost of clean coal dewatering is high during the wet separation process, which directly affects the economic benefits of coal preparation plants.

[0003] Dry separation technology provides an effective solution to the above problems. Dry separation has advantages such as no water required, simple process system, low investment, short construction period, and low operating cost, and is particularly suitable for the separation of low-rank, easily muddy raw coal in arid and water-scarce areas.

[0004] However, dry separators still have many shortcomings in practical applications. Existing dry separators have low separation accuracy, poor middlings separation, and some clean coal is mixed in. Direct discharge of this middlings would waste coal resources and reduce the clean coal yield and economic benefits of the coal preparation plant. To solve this problem, existing technologies typically use belt conveyors or other transfer equipment to collect the separated middlings and re-transport them to the dry separator's feed end for further separation—a process known as middlings rewashing. While this rewashing method achieves some degree of middlings re-selection, it also introduces new drawbacks: First, it requires additional belt conveyors, transfer points, and related control systems, leading to a complex dry separator system layout and increased equipment footprint. Second, the re-washing of middlings through transfer equipment increases material transport distance and time, reducing the dry separator's processing capacity per unit time. Furthermore, multiple transfers and rewashings can interfere with the particle size distribution and bed stability of the material, thus affecting the final separation accuracy. Summary of the Invention

[0005] The purpose of this invention is to provide a dry separation system with middlings re-selection function. Through the structural integration and innovation of two-stage separation beds, it achieves efficient middlings re-selection, simplifies equipment layout, and improves production efficiency and separation accuracy.

[0006] To achieve the above objectives, the present invention provides a dry separation system with middlings re-separation function, comprising: A sorting unit includes a sorting bed, an air inlet device, and a vibration motor for driving the sorting bed to vibrate. The air inlet device is located below the sorting bed and is used to supply air to the sorting bed. The discharge end of the sorting bed is provided with a clean coal outlet, a middlings coal outlet, and a gangue outlet in sequence. The sorting bed has a first back plate, which is opposite to the discharge end of the sorting bed. The two-stage sorting unit includes a two-stage sorting bed, a two-stage air inlet device, and a two-stage vibration motor for driving the two-stage sorting bed to vibrate. The two-stage air inlet device is located below the two-stage sorting bed and is used to supply air to the two-stage sorting bed. The discharge end of the two-stage sorting bed is provided with a clean coal outlet and a gangue outlet. The two-stage sorting bed has a second back plate, which is opposite to the discharge end of the two-stage sorting bed. The inlet end of the middlings product chute is used to connect to the middlings outlet of the discharge end of the first-stage sorting bed, and the outlet end of the middlings product chute leads to the feed end of the second-stage sorting bed.

[0007] Optionally, the first-stage sorting unit includes a discharge plate installed at the discharge end of the first-stage sorting bed. The discharge plate is sequentially provided with a clean coal section, a middlings section, and a gangue section, corresponding one-to-one with the clean coal outlet, middlings outlet, and gangue outlet of the first-stage sorting bed. The middlings section of the discharge plate is connected to the inlet end of the middlings product chute. The second-stage sorting unit includes two discharge plates installed at the discharge end of the second-stage sorting bed. The discharge plates are provided with a clean coal section and a gangue section, corresponding one-to-one with the clean coal outlet and gangue outlet of the second-stage sorting bed.

[0008] Optionally, the dry sorting system includes a product chute located below the discharge plate. The product chute includes a first clean coal chute and a first gangue chute. The inlet of the first clean coal chute corresponds to the clean coal section of the discharge plate, and the inlet of the first gangue chute corresponds to the gangue section of the discharge plate.

[0009] Optionally, the dry separation system includes two product chutes located below the two-stage discharge plates. The two product chutes include a second clean coal chute and a second gangue chute. The inlet position of the second clean coal chute corresponds to the clean coal section of the two-stage discharge plates, and the inlet position of the second gangue chute corresponds to the gangue section of the two-stage discharge plates.

[0010] Optionally, at the junction of the first discharge plate and the bed surface of the first sorting bed, the upper surface of the first discharge plate is higher than the bed surface of the first sorting bed; at the junction of the second discharge plate and the bed surface of the second sorting bed, the upper surface of the second discharge plate is higher than the bed surface of the second sorting bed; the dry sorting system includes a first servo motor and a second servo motor, the first servo motor being used to adjust the height of the first discharge plate, and the second servo motor being used to adjust the height of the second discharge plate.

[0011] Optionally, the outlet end of the coal product chute is connected to the feed end of the second-stage sorting bed via a connector, the connector being used to allow coal particles to pass through, preventing coal particles from falling outside the second-stage sorting bed.

[0012] Optionally, the first-stage air intake device includes multiple spaced-apart first-stage air intake pipes, the airflow of each first-stage air intake pipe being adjustable; the second-stage air intake device includes multiple spaced-apart second-stage air intake pipes, the airflow of each second-stage air intake pipe being adjustable.

[0013] Optionally, the airflow strength of the multiple section air inlet pipes is configured such that: the airflow strength decreases from the feed end of the section sorting bed to the gangue outlet of the section sorting bed, and the airflow strength decreases from the first back plate to the discharge end of the section sorting bed; the airflow strength of the multiple section air inlet pipes is configured such that: the airflow strength decreases from the feed end of the section sorting bed to the gangue outlet of the section sorting bed, and the airflow strength decreases from the second back plate to the discharge end of the section sorting bed.

[0014] Optionally, a gap is left between the first-stage sorting bed and the second-stage sorting bed to ensure that the first-stage sorting bed and the second-stage sorting bed do not come into contact during vibration.

[0015] Optionally, the dry sorting system includes a dust removal device, which is located above the first-stage sorting bed and the second-stage sorting bed, and uses negative pressure to suck up dust.

[0016] With the above configuration, the dry separation system with middlings re-selection function of the present invention has the following advantages compared with the prior art: First, this invention simplifies system layout and reduces equipment investment costs. It employs two sorting beds with a middlings product chute between them. The middlings produced in the first sorting bed are directly transported to the second sorting bed for further processing via this chute. Compared to traditional middlings rewashing methods, this eliminates the need for belt conveyors, transfer points, and related electrical control equipment, significantly simplifying system layout, reducing equipment footprint, and lowering equipment investment and installation costs for manufacturers.

[0017] Secondly, this invention enhances the processing capacity of the dry sorting system while ensuring sorting accuracy. It avoids material transport delays and system interruptions caused by external transfers, thus improving the continuous operation capability of the dry sorting system. Simultaneously, by adjusting the airflow in the primary and secondary air inlets and by adjusting the discharge plate height, the sorting process parameters can be optimized according to changes in coal quality, ensuring sufficient stratification of materials of different density levels and effectively improving clean coal yield and sorting accuracy.

[0018] Third, this invention reduces maintenance workload and lowers operating costs. By eliminating external conveyor belts and other transfer equipment, the system's potential failure points are significantly reduced, consequently lowering the workload of daily maintenance and repair. Furthermore, the dust removal device effectively collects dust generated during the sorting process, improving the working environment and benefiting the health of workers. Attached Figure Description

[0019] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein: Figure 1 This is a schematic diagram of a dry separation system with middlings re-selection function according to an embodiment of the present invention.

[0020] The accompanying figure is labeled as follows: 11-First stage sorting bed; 111-First back plate; 112-First side plate; 12-First stage air inlet device; 13-First stage vibrating motor; 14-First stage discharge plate; 2-Mid-coal product chute; 31-Second stage sorting bed; 311-Second back plate; 312-Second side plate; 32-Second stage air inlet device; 33-Second stage vibrating motor; 34-Second stage discharge plate; 4-First stage product chute; 5-Second stage product chute; 61-Dust collector hood; 62-Pipeline; 7-Frame. Detailed Implementation

[0021] In this document, unless otherwise stated, the terms “upper,” “lower,” “left,” “right,” “inner,” “outer,” “front,” “back,” “top,” “bottom,” etc., are used to indicate orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a characteristic orientation and operation, and therefore should not be construed as a limitation of the invention.

[0022] The specific embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0023] Figure 1 This is a schematic diagram of a dry separation system with middlings re-separation function according to an embodiment of the present invention. Please refer to it. Figure 1 This invention provides a dry separation system with middlings re-selection function, including a first-stage separation unit, a second-stage separation unit, and a middlings product chute 2.

[0024] A single-stage sorting unit includes a single-stage sorting bed 11, a single-stage air inlet device 12, and a single-stage vibration motor 13 for driving the single-stage sorting bed 11 to vibrate. The single-stage air inlet device 12 is located below the single-stage sorting bed 11 and is used to supply air to the single-stage sorting bed 11. The discharge end of the single-stage sorting bed 11 is provided with a clean coal outlet, a middlings outlet, and a gangue outlet in sequence. The single-stage sorting bed 11 has a first back plate 111, which is opposite to the discharge end of the single-stage sorting bed 11. It can be understood that the bed surface of the single-stage sorting bed 11 is surrounded on three sides except for the discharge end side. The side opposite to the discharge end is surrounded by the first back plate 111, and the other two sides are each surrounded by a first side plate 112. The single-stage vibration motor 13 is mounted on the first back plate 111.

[0025] Furthermore, the first-stage sorting unit includes a discharge plate 14, which is installed at the discharge end of the first-stage sorting bed 11. It is understood that the discharge plate 14 is connected to the bed surface of the first-stage sorting bed 11. The discharge plate 14 is sequentially provided with a clean coal section, a middlings coal section, and a gangue section, corresponding one-to-one with the clean coal outlet, middlings coal outlet, and gangue outlet of the first-stage sorting bed 11. The middlings coal section of the discharge plate 14 is connected to the inlet end of the middlings coal product chute 2.

[0026] Preferably, at the junction of the discharge plate 14 and the bed surface of the sorting bed 11, the upper surface of the discharge plate 14 is higher than the bed surface of the sorting bed 11. The dry separation system includes a first servo motor, which is used to adjust the height of the discharge plate 14, and the height can be adjusted online according to the coal quality. It is understood that the height of the discharge plate 14 directly determines the residence time of the material on the bed surface. When the discharge plate 14 is raised, the material needs to accumulate higher before overflowing, and the residence time is extended, which is conducive to the full stratification of the material. When the discharge plate 14 is lowered, the material is discharged faster, the throughput increases, but the separation accuracy may be sacrificed. When the material properties (such as particle size distribution and ash content) change, the separation effect can be optimized by adjusting the height of the discharge plate to ensure the yield of clean coal.

[0027] The dry sorting system includes a product chute 4 located below the discharge plate 14. The product chute 4 comprises a first clean coal chute and a first gangue chute. The inlet of the first clean coal chute corresponds to the clean coal section of the discharge plate 14, and it receives the clean coal separated by the sorting bed 11 and feeds it onto a clean coal conveyor belt (not shown in the figure). The inlet of the first gangue chute corresponds to the gangue section of the discharge plate 14, and it receives the gangue separated by the sorting bed 11 and feeds it onto a gangue conveyor belt (not shown in the figure).

[0028] The two-stage sorting unit includes a two-stage sorting bed 31, a two-stage air inlet device 32, and a two-stage vibration motor 33 for driving the two-stage sorting bed 31 to vibrate. The two-stage air inlet device 32 is located below the two-stage sorting bed 31 and is used to supply air to the two-stage sorting bed 31. The discharge end of the two-stage sorting bed 31 is provided with a clean coal outlet and a gangue outlet. The two-stage sorting bed 31 has a second back plate 311, which is opposite to the discharge end of the two-stage sorting bed 31. It can be understood that the bed surface of the two-stage sorting bed 31 is surrounded on three sides except for the discharge end side. The side opposite to the discharge end is surrounded by the second back plate 311, and the other two sides are each surrounded by a second side plate 312. The two-stage vibration motor 33 is mounted on the second back plate 311.

[0029] Furthermore, the two-stage sorting unit includes a two-stage discharge plate 34, which is installed at the discharge end of the two-stage sorting bed 31. It can be understood that the two-stage discharge plate 34 is connected to the bed surface of the two-stage sorting bed 31. The two-stage discharge plate 34 is provided with a clean coal section and a gangue section, corresponding one-to-one with the clean coal outlet and gangue outlet of the two-stage sorting bed 31.

[0030] Preferably, at the junction of the second-stage discharge plate 34 and the bed surface of the second-stage sorting bed 31, the upper surface of the second-stage discharge plate 34 is higher than the bed surface of the second-stage sorting bed 31. The dry sorting system includes a first servo motor and a second servo motor. The first servo motor is used to adjust the height of the first-stage discharge plate 14, and the second servo motor is used to adjust the height of the second-stage discharge plate 34. The height can be adjusted online according to the coal quality. The function of adjusting the height of the second-stage discharge plate 34 is the same as that of the first-stage discharge plate 14.

[0031] The dry separation system includes two product chutes 5 located below the two-stage discharge plate 34. Each product chute 5 comprises a second clean coal chute and a second gangue chute. The inlet of the second clean coal chute corresponds to the clean coal section of the two-stage discharge plate 34, and it receives the clean coal separated by the two-stage separation beds and feeds it onto the clean coal conveyor belt. The inlet of the second gangue chute corresponds to the gangue section of the two-stage discharge plate 34, and it receives the gangue separated by the two-stage separation beds and feeds it onto the gangue conveyor belt. It is understood that the clean coal separated by the two-stage separation beds is mixed with the clean coal separated by the first-stage separation bed, and the gangue separated by the two-stage separation beds is mixed with the gangue separated by the first-stage separation bed. Therefore, it can be seen that after the two-stage separation bed, only two materials are separated: clean coal and gangue, which realizes the complete separation of middlings and greatly improves the separation efficiency and clean coal output.

[0032] The inlet end of the middlings product chute 2 is connected to the middlings outlet of the discharge end of the first-stage sorting bed 11, and the outlet end of the middlings product chute 2 leads to the feed end of the second-stage sorting bed 31. Furthermore, the outlet end of the middlings product chute 2 is connected to the feed end of the second-stage sorting bed 31 via a connector. This connector allows coal particles to pass through, preventing them from falling outside the second-stage sorting bed 31 and damaging the equipment. For example, the connector can be a flexible connector, such as rubber.

[0033] A gap is maintained between the first-stage sorting bed 11 and the second-stage sorting bed 31 to ensure that they do not come into contact during vibration. For example, the vertical distance between the outlet end of the coal product chute 2 and the second-stage sorting bed is controlled at 30mm-50mm to ensure sufficient distance between the two sorting bed surfaces.

[0034] Understandably, both the first-stage sorting bed 11 and the second-stage sorting bed 31 have inclined surfaces.

[0035] Preferably, the first-stage air inlet device 12 includes multiple spaced-apart first-stage air inlet pipes, with the outlet of each first-stage air inlet pipe facing the surface of the first-stage sorting bed 11. The airflow strength of each first-stage air inlet pipe is adjustable; for example, a solenoid valve can be installed in each first-stage air inlet pipe to achieve automatic control of the airflow strength. The second-stage air inlet device 32 includes multiple spaced-apart second-stage air inlet pipes, with the outlet of each second-stage air inlet pipe facing the surface of the second-stage sorting bed. The airflow strength of each second-stage air inlet pipe is adjustable; for example, a solenoid valve can be installed in each second-stage air inlet pipe to achieve automatic control of the airflow strength. Figure 1 To simplify the drawing method, Figure 1 The multiple single-stage air inlet pipes and multiple double-stage air inlet pipes are not shown in the figure. They can be regarded as multiple single-stage air inlet pipes in the single-stage air inlet device 12 and multiple double-stage air inlet pipes in the double-stage air inlet device 32.

[0036] The airflow strength of the multiple section air inlet pipes is configured such that: the airflow is reduced along the direction from the feed end of the section sorting bed 11 to the gangue outlet of the section sorting bed 11, and the airflow is reduced along the direction from the first back plate 111 to the discharge end of the section sorting bed 11; the airflow strength of the multiple section air inlet pipes is configured such that: the airflow is reduced along the direction from the feed end of the section sorting bed 31 to the gangue outlet of the section sorting bed 31, and the airflow is reduced along the direction from the second back plate 311 to the discharge end of the section sorting bed 31. Understandably, when raw coal first enters the sorting bed, the material layer is thick and densely packed. Stronger airflow is used here to quickly disperse the material, breaking up the packing and creating sufficient gaps between particles to facilitate subsequent density-based stratification. As the material moves towards the gangue outlet, the heavier particles have already begun to separate into layers. At this point, the airflow is appropriately reduced to maintain the established stratification and prevent excessively strong airflow from re-blowing up the settled heavier particles, interfering with the sorting process. Upon reaching the gangue outlet, the gangue has settled to the bottom of the bed, where the airflow is weakest. This prevents the airflow from re-blowing up small amounts of clean coal within the gangue, causing mismatch, and also prevents the gangue from being dispersed by the wind, affecting discharge. The back plate is the edge baffle of the sorting bed. Under the influence of vibration and airflow, denser gangue tends to accumulate towards the back plate. Stronger airflow is used on the back plate side to help "blow up" the gangue accumulated near the back plate and push it towards the discharge end, preventing gangue from accumulating on the back plate side and forming a dead zone. The wind is weaker near the discharge end, which helps the gangue that has moved to the vicinity of the discharge end to settle smoothly onto the bed surface and be discharged through the discharge plate, preventing it from being rolled back to the middle of the bed surface by the wind.

[0037] The dry sorting system includes a dust removal device positioned above the first-stage sorting bed 11 and the second-stage sorting bed 31, which draws in dust using negative pressure. Specifically, the dust removal device includes a dust hood 61 and a pipe 62. The dust hood 61 covers the first-stage and second-stage sorting beds 11 and 31, and is connected to the pipe 62, thereby drawing dust into the pipe for subsequent dust processing. It is understood that the dry sorting system also includes a frame 7, on which the dust removal device is mounted.

[0038] With the above configuration, the dry separation system with middlings re-selection function of the present invention has the following advantages compared with the prior art: First, this invention simplifies system layout and reduces equipment investment costs. This invention employs two sorting beds, with a middlings product chute 2 positioned between them. The middlings produced by the first-stage sorting bed 11 are directly transported to the second-stage sorting bed 31 for further sorting via the middlings product chute 2. Compared to traditional middlings rewashing methods, this eliminates the need for belt conveyors, transfer points, and related electrical control equipment, significantly simplifying system layout, reducing equipment footprint, and lowering equipment investment and installation costs for manufacturers.

[0039] Secondly, this invention enhances the processing capacity of the dry sorting system while ensuring sorting accuracy. It avoids material transport delays and system interruptions caused by external transfers, thus improving the continuous operation capability of the dry sorting system. Simultaneously, by adjusting the airflow in the primary air intake device 12 and the secondary air intake device 32, as well as adjusting the discharge plate height, the sorting process parameters can be optimized according to changes in coal quality, ensuring sufficient stratification of materials of different density levels and effectively improving clean coal yield and sorting accuracy.

[0040] Third, this invention reduces maintenance workload and lowers operating costs. By eliminating external conveyor belts and other transfer equipment, the system's potential failure points are significantly reduced, consequently lowering the workload of daily maintenance and repair. Furthermore, the dust removal device effectively collects dust generated during the sorting process, improving the working environment and benefiting the health of workers.

[0041] It should be noted that references to "an embodiment," "an embodiment," "a specific embodiment," "some embodiments," etc., in the specification only indicate that the described embodiment may include a specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in conjunction with an embodiment, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.

[0042] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0043] It should also be noted that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

[0044] It should also be understood that, unless otherwise specified or indicated, the terms “first,” “second,” “third,” etc., in the specification are used only to distinguish the various components, elements, and steps in the specification, and not to indicate the logical or sequential relationships between the various components, elements, and steps.

[0045] Furthermore, it should be recognized that the terminology described herein is used only to describe particular embodiments and is not intended to limit the scope of the invention. It must be noted that the singular forms “a” and “an” as used herein include plural bases unless the context clearly indicates otherwise. For example, a reference to “a step” or “an apparatus” means a reference to one or more steps or apparatuses, and may include secondary steps and secondary apparatuses. All conjunctions used should be understood in the broadest sense. Also, the word “or” should be understood to have the definition of logical “or” rather than logical “exclusive OR”, unless the context clearly indicates otherwise. Furthermore, implementation of the methods and / or devices in embodiments of the invention may include performing selected tasks manually, automatically, or in combination.

Claims

1. A dry separation system with middlings re-separation function, characterized in that, include: A sorting unit includes a sorting bed, an air inlet device, and a vibration motor for driving the sorting bed to vibrate. The air inlet device is located below the sorting bed and is used to supply air to the sorting bed. The discharge end of the sorting bed is provided with a clean coal outlet, a middlings coal outlet, and a gangue outlet in sequence. The sorting bed has a first back plate, which is opposite to the discharge end of the sorting bed. The two-stage sorting unit includes a two-stage sorting bed, a two-stage air inlet device, and a two-stage vibration motor for driving the two-stage sorting bed to vibrate. The two-stage air inlet device is located below the two-stage sorting bed and is used to supply air to the two-stage sorting bed. The discharge end of the two-stage sorting bed is provided with a clean coal outlet and a gangue outlet. The two-stage sorting bed has a second back plate, which is opposite to the discharge end of the two-stage sorting bed. The inlet end of the middlings product chute is used to connect to the middlings outlet of the discharge end of the first-stage sorting bed, and the outlet end of the middlings product chute leads to the feed end of the second-stage sorting bed.

2. The dry separation system with middlings re-separation function as described in claim 1, characterized in that, The first-stage sorting unit includes a discharge plate installed at the discharge end of the first-stage sorting bed. The discharge plate is sequentially provided with a clean coal section, a middlings section, and a gangue section, corresponding one-to-one with the clean coal outlet, middlings outlet, and gangue outlet of the first-stage sorting bed. The middlings section of the discharge plate is connected to the inlet end of the middlings product chute. The second-stage sorting unit includes two discharge plates installed at the discharge end of the second-stage sorting bed. The discharge plates are provided with a clean coal section and a gangue section, corresponding one-to-one with the clean coal outlet and gangue outlet of the second-stage sorting bed.

3. The dry separation system with middlings re-selection function as described in claim 2, characterized in that, The dry sorting system includes a product chute located below the discharge plate. The product chute includes a first clean coal chute and a first gangue chute. The inlet of the first clean coal chute corresponds to the clean coal section of the discharge plate, and the inlet of the first gangue chute corresponds to the gangue section of the discharge plate.

4. The dry separation system with middlings re-separation function as described in claim 2, characterized in that, The dry sorting system includes two product chutes located below the two discharge plates. The two product chutes include a second clean coal chute and a second gangue chute. The inlet of the second clean coal chute corresponds to the clean coal section of the two discharge plates, and the inlet of the second gangue chute corresponds to the gangue section of the two discharge plates.

5. The dry separation system with middlings re-separation function as described in claim 2, characterized in that, At the junction of the first discharge plate and the bed surface of the first sorting bed, the upper surface of the first discharge plate is higher than the bed surface of the first sorting bed; at the junction of the second discharge plate and the bed surface of the second sorting bed, the upper surface of the second discharge plate is higher than the bed surface of the second sorting bed; the dry sorting system includes a first servo motor and a second servo motor, the first servo motor being used to adjust the height of the first discharge plate, and the second servo motor being used to adjust the height of the second discharge plate.

6. The dry separation system with middlings re-separation function as described in claim 1, characterized in that, The outlet end of the coal product chute is connected to the feed end of the second-stage sorting bed via a connector. The connector is used to allow coal particles to pass through, preventing coal particles from falling outside the second-stage sorting bed.

7. The dry separation system with middlings re-separation function as described in claim 1, characterized in that, The first-stage air intake device includes multiple spaced-apart air intake pipes, and the airflow of each air intake pipe is adjustable; the second-stage air intake device includes multiple spaced-apart air intake pipes, and the airflow of each air intake pipe is adjustable.

8. The dry separation system with middlings re-separation function as described in claim 7, characterized in that, The airflow strength of the multiple section air inlet pipes is configured such that: the airflow is reduced from the feed end of the section sorting bed to the gangue outlet of the section sorting bed, and the airflow is reduced from the first back plate to the discharge end of the section sorting bed; the airflow strength of the multiple section air inlet pipes is configured such that: the airflow is reduced from the feed end of the section sorting bed to the gangue outlet of the section sorting bed, and the airflow is reduced from the second back plate to the discharge end of the section sorting bed.

9. The dry separation system with middlings re-separation function as described in claim 1, characterized in that, A gap is left between the first-stage sorting bed and the second-stage sorting bed to ensure that the first-stage sorting bed and the second-stage sorting bed do not come into contact during vibration.

10. The dry separation system with middlings re-separation function as described in claim 1, characterized in that, The dry sorting system includes a dust removal device, which is located above the first-stage sorting bed and the second-stage sorting bed, and uses negative pressure to suck up dust.

Images