Gangue particle discharging assembly, discharging method and coal grading system

Abstract

The invention discloses a gangue particle discharging assembly, a gangue particle discharging method and a coal grading system, belongs to the technical field of coal grading, and aims to solve the problem that the grading efficiency of coal is affected due to the fact that graded gangue particles cannot be discharged in time in the prior art. In the discharging assembly, the discharging conversion plate has a discharging port mode, a channel mode and a composite mode; the discharging conversion plate is in a discharging opening mode, the discharging conversion plate covers the particle channel, and the particle discharging opening communicates with the coal grading cavity; the discharging conversion plate is in a channel mode, the discharging conversion plate covers the particle discharging opening, and the coal grading cavity communicates with the particle channel; and the discharging conversion plate is in a composite mode, the discharging conversion plate does not cover the particle discharging opening and the particle channel, and the particle discharging opening and the particle channel are both communicated with the coal grading cavity. The discharging device can be used for discharging gangue particles obtained after coal grading.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal classification, and particularly relates to a discharge assembly for gangue particles, a discharge method and a coal classification system. Background Art

[0002] Dry coal classification is an efficient and environmentally friendly classification technology. Without the aid of a water medium, coal is classified according to density by mechanical vibration and / or air separation.

[0003] For the discharge of gangue particles after classification, a discharge port is usually provided on the sorting cavity. However, this discharge method is single. For coals with different gangue particle contents, the discharge method cannot be adjusted according to the amount of gangue particles, and it is easy for gangue particles to accumulate at the discharge port and cannot be discharged in time, thus affecting the classification efficiency of coal. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a discharge assembly for gangue particles, a discharge method and a coal classification system to solve the problem in the prior art that the gangue particles after classification cannot be discharged in time, affecting the classification efficiency of coal.

[0005] The object of the present invention is mainly achieved through the following technical solutions.

[0006] The present invention provides a discharge assembly for gangue particles for discharging the gangue particles obtained after coal classification; the discharge assembly includes a particle discharge port, a particle channel and a discharge conversion plate. The particle discharge port is opened at the bottom of the coal classification cavity, and the particle channel is communicated with the bottom of the coal classification cavity; the discharge conversion plate has a discharge port mode, a channel mode and a composite mode; when the discharge conversion plate is in the discharge port mode, the discharge conversion plate covers the particle channel, and the particle discharge port is communicated with the coal classification cavity; when the discharge conversion plate is in the channel mode, the discharge conversion plate covers the particle discharge port, and the coal classification cavity is communicated with the particle channel; when the discharge conversion plate is in the composite mode, the discharge conversion plate does not cover the particle discharge port and the particle channel, and both the particle discharge port and the particle channel are communicated with the coal classification cavity.

[0007] Further, the discharge conversion plate is arranged between the particle discharge port and the particle channel, and the discharge conversion plate is rotatably connected to the coal classification cavity.

[0008] Further, the discharge assembly further includes a conversion plate driving member for driving the discharge conversion plate to rotate.

[0009] Further, the discharge assembly further includes a mode controller and an ash detector for detecting the ash content of raw coal before classification. The mode controller is respectively connected to the ash detector and the conversion plate driving member.

[0010] Further, the discharging assembly further includes a discharging port belt and a channel belt. The feeding end of the discharging port belt is arranged below the granular discharging port, and the channel belt is arranged below the granular channel.

[0011] The present invention also provides a discharging method for gangue particles. By using the above-mentioned discharging assembly for gangue particles, the discharging method includes the following steps:

[0012] Step a: Detect the ash content of raw coal before classification in real time, and determine whether the ash content of raw coal before classification is within the threshold range;

[0013] Step b: If it is lower than the threshold range, the discharging conversion plate is in the discharging port mode, the discharging conversion plate covers the granular channel, and the granular discharging port is communicated with the coal classification cavity;

[0014] If it is within the threshold range, the discharging conversion plate is in the channel mode, the discharging conversion plate covers the granular discharging port, and the coal classification cavity is communicated with the granular channel;

[0015] If it is higher than the threshold range, the discharging conversion plate is in the composite mode, the discharging conversion plate does not cover the granular discharging port and the granular channel, and both the granular discharging port and the granular channel are communicated with the coal classification cavity.

[0016] Further, the threshold range is 20-45%.

[0017] The present invention also provides a coal classification system, including the above-mentioned discharging assembly for gangue particles.

[0018] Further, the coal classification system further includes a coal classification cavity, a first-stage air supply member, an orifice plate, and a second-stage air supply member; the orifice plate and the second-stage air supply member are arranged on one side inside the coal classification cavity from top to bottom. The space between the top surface of the coal classification cavity and the orifice plate is the rough coal cleaning chamber, the space between the orifice plate and the second-stage air supply member is the second-stage classification chamber, and the space between the second-stage air supply member and the bottom surface of the coal classification cavity is the granular channel.

[0019] Further, there is a gap between the first-stage air supply member and the lower wall surface of the granular channel, and the gap serves as the granular discharging port. One end of the discharging conversion plate is rotatably connected to the side of the granular channel close to the gap, and the other end is a free end; one end of the first-stage air supply member close to the granular discharging port is rotatably connected to the coal classification cavity, and the other end of the first-stage air supply member is a free end.

[0020] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0021] The discharge assembly for gangue particles provided by the present invention is provided with two discharge assemblies (particle discharge ports and particle channels) at the same time, and controls the connection between the particle discharge ports and / or the particle channels and the coal classification cavity through a discharge conversion plate to adjust the specific discharge mode, that is, discharging through the particle discharge ports, discharging through the particle channels, or discharging through the particle discharge ports and the particle channels at the same time. Therefore, the appropriate discharge mode can be selected according to the specific amount of gangue particles to ensure the timely discharge of gangue particles in the coal classification cavity and effectively improve the classification efficiency of coal.

[0022] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the following specification, and some advantages can be made obvious from the specification, or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the content specifically pointed out in the embodiments of the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are only for the purpose of showing specific embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference signs represent the same components.

[0024] Figure 1 It is a schematic structural diagram of the discharge assembly for gangue particles provided by Embodiment 1 of the present invention, wherein the discharge conversion plate is in the discharge port mode;

[0025] Figure 2 It is a schematic structural diagram of the discharge assembly for gangue particles provided by Embodiment 1 of the present invention, wherein the discharge conversion plate is in the channel mode;

[0026] Figure 3 It is a schematic structural diagram of the discharge assembly for gangue particles provided by Embodiment 1 of the present invention, wherein the discharge conversion plate is in the composite mode;

[0027] Figure 4 It is a schematic structural diagram of the coal classification system provided by Embodiment 3 of the present invention;

[0028] Figure 5 It is an internal schematic diagram of the coal classification system provided by Embodiment 3 of the present invention;

[0029] Figure 6 It is a schematic structural diagram of the main air supply chamber in the coal classification system provided by Embodiment 3 of the present invention.

[0030] Reference Signs:

[0031] Ⅰ - First-stage classification area; Ⅱ - Crude selected clean coal chamber; Ⅲ - Second-stage classification chamber; Ⅳ - Particle channel;

[0032] 101 - Coal classification cavity; 1011 - Raw coal feed inlet; 102 - Primary air supply component; 1021 - Main air supply chamber; 1022 - Main air supply plate; 1023 - First elastic ring; 1024 - Second elastic ring; 1025 - First sub - pipe; 1026 - Second sub - pipe; 1027 - Exhaust pump; 103 - Secondary air supply component; 104 - Orifice plate; 105 - Discharge conversion plate; 106 - Particle discharge port. Detailed implementation mode

[0033] The following combines the drawings to specifically describe the preferred embodiments of the present invention. Among them, the drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0034] Embodiment 1

[0035] This embodiment provides a discharge assembly for gangue particles, which is used for discharging the gangue particles obtained after coal classification. The discharge assembly includes a particle discharge port 106, a particle channel IV, and a discharge conversion plate 105. Among them, the particle discharge port 106 is opened at the bottom of the coal classification cavity, and the particle channel IV is communicated with the bottom of the coal classification cavity.

[0036] The discharge conversion plate 105 has a discharge port mode, a channel mode, and a composite mode.

[0037] When the discharge conversion plate 105 is in the discharge port mode, see Figure 1 , the discharge conversion plate 105 covers the particle channel IV, and the particle discharge port 106 is communicated with the coal classification cavity; when the discharge conversion plate 105 is in the channel mode, see Figure 2 , the discharge conversion plate 105 covers the particle discharge port 106, and the coal classification cavity 101 is communicated with the particle channel IV; when the discharge conversion plate 105 is in the composite mode, see Figure 3 , the discharge conversion plate 105 does not cover the particle discharge port 106 and the particle channel IV, and both the particle discharge port 106 and the particle channel IV are communicated with the coal classification cavity.

[0038] Compared with the prior art, the discharge assembly for gangue particles provided in this embodiment sets two discharge assemblies (particle discharge port 106 and particle channel IV) at the same time, and controls the communication between the particle discharge port 106 and / or the particle channel IV and the coal classification cavity 101 through the discharge conversion plate 105 to adjust the specific discharge method, that is, discharging through the particle discharge port 106, discharging through the particle channel IV, or discharging through the particle discharge port 106 and the particle channel IV at the same time. Thus, it can select a suitable discharge method according to the specific amount of gangue particles, ensure the timely discharge of gangue particles in the coal classification cavity 101, and effectively improve the coal classification efficiency.

[0039] In order to enable the mode switching of the discharge conversion plate 105, the discharge conversion plate 105 is arranged between the granular discharge port 106 and the granular channel IV, and the discharge conversion plate 105 is rotatably connected to the coal classification cavity 101 (for example, the bottom surface of the coal classification cavity 101).

[0040] Correspondingly, the discharge assembly of the above-mentioned gangue particles further includes a conversion plate driving member (for example, a driving motor) for driving the discharge conversion plate 105 to rotate. By driving the discharge conversion plate 105 to rotate through the conversion plate driving member, the mode switching of the discharge conversion plate 105 can be realized.

[0041] In order to obtain the amount of gangue particles so as to select a suitable discharge method, the discharge assembly of the above-mentioned gangue particles further includes a mode controller and an ash detector for detecting the ash content of raw coal before classification. The mode controller is respectively connected to the ash detector and the conversion plate driving member. During implementation, the ash detector detects the ash content of raw coal before classification in real time and transmits it to the mode controller, and the mode controller judges whether the ash content of raw coal before classification is within a threshold range (for example, 20% - 45%).

[0042] If it is lower than the threshold range, it indicates that the ash content in the raw coal is less and the amount of gangue particles is less. The mode controller sends a discharge port mode instruction to the conversion plate driving member, and the conversion plate driving member controls the discharge conversion plate 105 to be in the discharge port mode according to the discharge port mode instruction.

[0043] If it is within the threshold range, it indicates that the ash content and the amount of gangue particles in the raw coal are in an intermediate amount. The mode controller sends a channel mode instruction to the conversion plate driving member, and the conversion plate driving member controls the discharge conversion plate 105 to be in the channel mode according to the channel mode instruction.

[0044] If it is higher than the threshold range, it indicates that the ash content in the raw coal is more and the amount of gangue particles is more. The mode controller sends a composite mode instruction to the conversion plate driving member, and the conversion plate driving member controls the discharge conversion plate 105 to be in the composite mode according to the composite mode instruction.

[0045] It should be noted that the threshold range refers to the ash range composed of the ash corresponding to the switch from the composite mode to the channel mode and the ash corresponding to the switch from the channel mode to the discharge port mode.

[0046] In order to facilitate the timely transportation of the gangue particles discharged from the granular discharge port 106 and the granular channel IV, the discharge assembly of the above-mentioned gangue particles further includes a discharge port belt and a channel belt. The feeding end of the discharge port belt is arranged below the granular discharge port 106, and the channel belt is arranged below the granular channel IV.

[0047] Embodiment 2

[0048] This embodiment provides a method for discharging gangue particles, using the discharging assembly for gangue particles provided in Embodiment 1. The discharging method includes the following steps:

[0049] Step a: Detect the ash content of raw coal before classification in real time, and determine whether the ash content of raw coal before classification is within the threshold range;

[0050] Step b: If it is lower than the threshold range, the discharging conversion plate 105 is in the discharging port mode, the discharging conversion plate 105 covers the particle channel IV, and the particle discharging port 106 is communicated with the coal classification cavity;

[0051] If it is within the threshold range, the discharging conversion plate 105 is in the channel mode, the discharging conversion plate 105 covers the particle discharging port 106, and the coal classification cavity 101 is communicated with the particle channel IV;

[0052] If it is higher than the threshold range, the discharging conversion plate 105 is in the composite mode, the discharging conversion plate 105 does not cover the particle discharging port 106 and the particle channel IV, and both the particle discharging port 106 and the particle channel IV are communicated with the coal classification cavity 101.

[0053] Compared with the prior art, the beneficial effects of the method for discharging gangue particles provided in this embodiment are basically the same as those of the discharging assembly for gangue particles provided in Embodiment 1, and will not be elaborated here one by one.

[0054] Embodiment 3

[0055] This embodiment provides a coal classification system, see Figures 4 to 5 , including a coal classification cavity 101, a primary air supply member 102, an orifice plate 104, a secondary air supply member 103, and the discharging assembly for gangue particles provided in Embodiment 1.

[0056] Among them, the orifice plate 104 and the secondary air supply member 103 are arranged on one side inside the coal classification cavity 101 from top to bottom. The inner cavity of the coal classification cavity 101 is divided into a first-stage classification area I without the orifice plate 104 and the secondary air supply member 103 and a second-stage classification area with the orifice plate 104 and the secondary air supply member 103. The space between the top surface of the second-stage classification area and the orifice plate 104 is the rough-selected clean coal chamber II, the space between the orifice plate 104 and the secondary air supply member 103 is the second-stage classification chamber III, and the space between the secondary air supply member 103 and the bottom surface of the second-stage classification area is the particle channel IV. A raw coal feed port 1011 is opened in the first-stage classification area I. There is a gap between the first-stage air supply member 102 and the lower wall surface of the particle channel IV, and this gap serves as the particle discharge port 106. One end of the discharge conversion plate 105 is rotatably connected to the side of the particle channel IV close to the gap, and the other end is a free end. The raw coal feed port 1011 is located on the side of the top of the first-stage classification area I far from the second-stage classification area, and the particle discharge port 106 is located on the side of the bottom of the first-stage classification area I close to the second-stage classification area. The rough-selected clean coal chamber II is provided with a rough-selected clean coal discharge port, and the second-stage classification chamber III is provided with a medium coal discharge port and a re-selected clean coal discharge port. Considering the density of the medium coal and the re-selected clean coal, the re-selected clean coal discharge port is located above the medium coal discharge port.

[0057] During implementation, the raw coal enters the first-stage classification area I from the raw coal feed port 1011, and the air flow is supplied into the first-stage classification area I from the first-stage air supply member 102; in the first-stage classification area I, the raw coal is under the action of the combined force field of the vibration force and the air flow, and stratification occurs longitudinally in the coal classification cavity 101 according to the density difference. The rough-selected clean coal with a low density stays in the upper part of the first-stage classification area I, the gangue particles with a high density sink to the lower part of the first-stage classification area I, and the mixture of medium coal and re-selected clean coal with an intermediate density is suspended in the middle position of the first-stage classification area I; with the continuous addition of the raw coal, the gangue particles, rough-selected clean coal, medium coal, and re-selected clean coal in the first-stage classification area I are under the action of the thrust of the newly added raw coal and the vibration force and migrate horizontally; the rough-selected clean coal enters the rough-selected clean coal chamber II and is then discharged from the discharge port of the rough-selected clean coal chamber II as the clean coal product, and the gangue particles are discharged from the particle discharge port 106 and / or the particle channel IV; the air flow is supplied into the second-stage classification chamber III from the second-stage air supply member 103, and the medium coal and the re-selected clean coal enter the second-stage classification chamber III for secondary separation. The mixture of medium coal and re-selected clean coal is stratified again under the action of the combined force field of the vibration force and the air flow. The re-selected clean coal with a low density stays in the upper part of the second-stage classification chamber III and is then discharged from the re-selected clean coal discharge port, and the medium coal with a high density stays in the lower part of the second-stage classification chamber III and is then discharged from the medium coal discharge port.

[0058] The above coal grading system divides the coal grading cavity 101 into a first-stage grading area I, a rough-selected clean coal chamber II, a second-stage grading chamber III, and a particle channel IV through the setting of the orifice plate 104 and the second-stage air supply member 103. Among them, raw coal enters the first-stage grading area I for first-stage separation, which can realize the separation of gangue particles, rough-selected clean coal, and the mixture of middlings and re-selected clean coal. The mixture of middlings and re-selected clean coal enters the second-stage grading chamber III for second-stage separation, which can realize the separation of middlings and re-selected clean coal, and at the same time complete the full separation of gangue particles, rough-selected clean coal, re-selected clean coal, and middlings. The process flow is simple, the separation cost is low, and it can solve the problems such as low separation accuracy of 0.5-13mm fine coal and serious resource waste.

[0059] Specifically, for the structure of the first-stage air supply member 102, it includes a main air supply chamber 1021 fixedly connected to the coal grading cavity 101 and a main air supply plate 1022 covering the air outlet of the main air supply chamber 1021. The main air supply plate 1022 is provided with main air supply holes.

[0060] Considering that gangue particles will move along the main air supply plate 1022 to the particle discharge port 106 and / or the particle channel IV for discharge, in order to be able to adjust the discharge speed of gangue particles, one end of the main air supply plate 1022 close to the particle discharge port 106 is rotatably connected to the coal grading cavity 101, and the other end of the main air supply plate 1022 is a free end. When the amount of gangue particles is greater than the gangue threshold, the main air supply plate 1022 can be driven to rotate, increasing the inclination angle of the main air supply plate 1022 and accelerating the migration speed of gangue particles to avoid the occurrence of bed deadlock.

[0061] In order to be able to adjust the inclination angle of the main air supply plate 1022 by using air flow, for the case where the number of main air supply chambers 1021 is one, specifically for the structure of the main air supply chamber 1021, see Figure 6 , the main air supply chamber 1021 includes a first elastic ring 1023, a second elastic ring 1024, a first sub-tube 1025, and a second sub-tube 1026 sleeved outside the first sub-tube 1025. There is a gap between the second sub-tube 1026 and the first sub-tube 1025. The main air supply plate 1022 is divided into a central area and a surrounding area around the central area. The surrounding area is provided with main air supply holes, and the central area is not provided with main air supply holes. The air outlet of the first sub-tube 1025 covers the central area and is connected to the edge of the central area through the first elastic ring 1023. A suction pump 1027 is provided on the first sub-tube 1025. The air outlet of the second sub-tube 1026 covers the surrounding area and is connected to the edge of the surrounding area through the second elastic ring 1024.

[0062] When there is no need to increase the inclination angle of the main air supply plate 1022, only the second sub-tube 1026 supplies air into the first-stage classification zone I through the main air supply holes; when it is necessary to increase the inclination angle of the main air supply plate 1022, the air extraction pump 1027 is turned on, and at the same time, air flows are introduced into the first sub-tube 1025 and the second sub-tube 1026, so that the lengths of the first elastic ring 1023 and the second elastic ring 1024 increase, and the main air supply plate 1022 rotates clockwise, and the inclination angle of the main air supply plate 1022 increases. In this way, through the mutually cooperating first sub-tube 1025 and second sub-tube 1026, the rotation of the main air supply plate 1022 can be driven by the pressure of the air flow, so as to realize the adjustment of the inclination angle of the main air supply plate 1022 by using the air flow, without the need to be equipped with other additional driving mechanisms for the main air supply plate 1022.

[0063] For the structure of the second-stage air supply member 103, in order to improve the uniformity of air supply, specifically, it includes an air supply groove, a plate body and dividing ribs. The dividing ribs are arranged in the air supply groove and divide the air supply groove into a plurality of air supply sub-grooves. The air supply of the plurality of air supply sub-grooves is independently set, and air inlet holes are opened on each air supply sub-groove. The plate body covers the notch of the air supply groove, and the selected air supply holes are opened on the plate body.

[0064] In order to improve the sorting accuracy and avoid the mixture of medium coal and re-selected clean coal from being blocked on the side wall of the re-selection air supply plate, resulting in material backmixing, the above-mentioned re-selection air supply plate is inclined towards the first-stage classification zone I, so as to form a tip, which is convenient for accurately sorting gangue particles from the mixture of medium coal and re-selected clean coal.

[0065] In order to be able to adjust the height of the dividing material layer between the mixture of medium coal and re-selected clean coal and the coarsely selected clean coal, the above-mentioned orifice plate 104 is rotatably connected to the side wall of the coal classification cavity 101. By the relative rotation of the orifice plate 104, the sizes of the feed ports of the coarsely selected clean coal chamber II and the second-stage classification chamber III can be adjusted, so as to realize the adjustment of the height of the dividing material layer between the mixture of medium coal and re-selected clean coal and the coarsely selected clean coal. In this way, if the content of the coarsely selected clean coal in the raw coal exceeds the coarsely selected clean coal threshold range, the orifice plate 104 is rotated so that the free end of the orifice plate 104 is lower than the connecting end, and the feed port of the coarsely selected clean coal chamber II increases, increasing the processing capacity of the coarsely selected clean coal; if the content of the mixture of medium coal and re-selected clean coal in the raw coal exceeds the mixture threshold range, the orifice plate 104 is rotated so that the free end of the orifice plate 104 is higher than the connecting end, and the feed port of the second-stage classification chamber III increases, increasing the processing capacity of the mixture of medium coal and re-selected clean coal.

[0066] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A discharge assembly for gangue particles, characterized in that Discharging of the gangue particles obtained after coal classification; The discharging assembly includes a particle discharging port, a particle channel, and a discharging conversion plate. The particle discharging port is opened at the bottom of the coal classification cavity, and the particle channel is communicated with the bottom of the coal classification cavity; The discharging conversion plate has a discharging port mode, a channel mode, and a composite mode; When the discharging conversion plate is in the discharging port mode, the discharging conversion plate covers the particle channel, and the particle discharging port is communicated with the coal classification cavity; when the discharging conversion plate is in the channel mode, the discharging conversion plate covers the particle discharging port, and the coal classification cavity is communicated with the particle channel; when the discharging conversion plate is in the composite mode, the discharging conversion plate does not cover the particle discharging port and the particle channel, and both the particle discharging port and the particle channel are communicated with the coal classification cavity.

2. The discharging assembly for gangue particles according to claim 1, characterized in that, The discharging conversion plate is arranged between the particle discharging port and the particle channel, and the discharging conversion plate is rotatably connected with the coal classification cavity.

3. The discharging assembly for gangue particles according to claim 1, characterized in that, The discharging assembly further includes a conversion plate driving member for driving the discharging conversion plate to rotate.

4. The discharge assembly for gangue particles according to claim 3, wherein, The discharging assembly further includes a mode controller and an ash content detector for detecting the ash content of raw coal before classification. The mode controller is respectively connected with the ash content detector and the conversion plate driving member.

5. The discharging assembly for gangue particles according to claim 1, wherein The discharging assembly further includes a discharging port belt and a channel belt. The feeding end of the discharging port belt is arranged below the particle discharging port, and the channel belt is arranged below the particle channel.

6. A discharging method for gangue particles, characterized in that, Adopting the discharging assembly for gangue particles according to any one of claims 1 to 5, the discharging method includes the following steps: Step a: Detect the ash content of raw coal before classification in real time, and judge whether the ash content of raw coal before classification is within the threshold range; Step b: If it is lower than the threshold range, the discharging conversion plate is in the discharging port mode, the discharging conversion plate covers the particle channel, and the particle discharging port is communicated with the coal classification cavity; If it is within the threshold range, the discharging conversion plate is in the channel mode, the discharging conversion plate covers the particle discharging port, and the coal classification cavity is communicated with the particle channel; If it is higher than the threshold range, the discharging conversion plate is in the composite mode, the discharging conversion plate does not cover the particle discharging port and the particle channel, and both the particle discharging port and the particle channel are communicated with the coal classification cavity.

7. The discharging method of gangue particles according to claim 6, characterized in that, The threshold range is 20% - 45%.

8. A coal grading system, characterized in that, Including the discharging assembly for gangue particles according to any one of claims 1 to 5.

9. The coal grading system according to claim 8, characterized in that, The coal classification system further includes a coal classification cavity, a primary air supply member, an orifice plate, and a secondary air supply member; The orifice plate and the secondary air supply member are arranged on one side in the coal classification cavity from top to bottom. The space between the top surface of the coal classification cavity and the orifice plate is the rough selection clean coal chamber, the space between the orifice plate and the secondary air supply member is the secondary classification chamber, and the space between the secondary air supply member and the bottom surface of the coal classification cavity is the particle channel.

10. The coal classification system according to claim 9, characterized in that, There is a gap between the primary air supply member and the lower wall surface of the particle channel, and the gap serves as the particle discharging port; One end of the discharging conversion plate is rotatably connected to the side of the particle channel close to the gap, and the other end is a free end; One end of the primary air supply member close to the particle discharging port is rotatably connected to the coal classification cavity, and the other end of the primary air supply member is a free end.

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