A preprocessing device for coal dust classification detection using laser-induced breakdown spectroscopy

Abstract

A pretreatment device for laser-induced breakdown spectroscopy (LASPS) coal powder classification and detection includes a processing table. A refining box and a preparation box are fixedly mounted on the table surface. A pushing mechanism penetrating the upper part of the processing table is located on the lower inner side of the refining box. A grinding mechanism is positioned above the pushing mechanism. A feeding and stirring mechanism is located on the upper inner side of the preparation box, with its outlet connected to the inlet of a pressing mechanism penetrating the processing table surface. This invention uses the pushing mechanism to push coal blocks to the grinding mechanism for crushing and grinding, resulting in uniformly refined coal powder. The coal powder and boric acid powder are then placed in the feeding and stirring mechanism for proportional feeding and mixing, ensuring more rational material release and improved mixing effect. The mixed powder is then moved to the pressing mechanism for tableting. The resulting tablet samples for LASPS coal powder classification have the characteristics of uniform particle refinement, thorough raw material mixing, and good preparation effect.

Description

Technical Field

[0001] This invention belongs to the field of coal classification, detection and preparation technology, and particularly relates to a pretreatment device for coal powder classification and detection using laser-induced breakdown spectroscopy. Background Technology

[0002] Laser-induced breakdown spectroscopy (LAS) is essentially an atomic emission spectroscopy technique. It uses a high-energy pulsed laser to ablate and excite the sample surface, generating plasma. During quenching, the plasma emits bremsstrahlung radiation and characteristic spectral lines. By analyzing the wavelength and intensity of these characteristic lines, qualitative and quantitative analysis of the sample can be achieved. Applying this technique to coal classification and detection can significantly improve accuracy. However, when used for coal classification and detection, basic processing of the coal raw materials is necessary. Mixing it with boric acid and pressing it into flakes yields better processing and analysis results. Typically, a simple mixing and extrusion mechanism is used for raw material preparation. However, due to insufficient refinement of the coal material itself, inconsistent particle sizes, and the simplistic mixing process, the actual raw material preparation effect is poor, resulting in uneven samples that significantly affect the subsequent spectral quality. Therefore, effective processing of the raw materials is crucial for its application in coal classification and detection.

[0003] Chinese invention patent application number 201810827113.7 discloses a media grinding and stirring mechanism. This mechanism includes a fixed base plate, a mounting shell fixed to the top surface of the fixed base plate, a mounting groove formed in the center of the top surface of the mounting shell, and a bottom mounting slot on the bottom surface of the mounting groove. An electromagnet plate is inserted into the bottom mounting slot, and the bottom surface of the electromagnet plate is fixed to the bottom surface of the bottom mounting slot. An elastic buffer layer is fixed to the inner wall of the mounting groove, and a grinding and dispensing container is placed in the mounting groove. In this technology, the grinding and dispensing container is fixed by an electromagnet plate and a clamping cylinder, which is convenient for fixing, installation, and disassembly. Furthermore, the grinding and dispensing container is equipped with a grinding basin, allowing the ground powder to be poured into the container for accumulation without the need for an additional receiving device. Multiple batches of material can be ground in the grinding basin and accumulated in the grinding and dispensing container, which can then be removed all at once to retrieve the ground powder, making it very convenient and requiring minimal external space. Because this device uses a grinding motor to drive the grinding balls in the grinding basin to grind the material, it has the disadvantage of insufficient fineness of the coal material itself and inconsistent particle size.

[0004] Chinese invention patent application number 201911074524.4 discloses a pesticide and fertilizer mixing device, including a base, a mixing cylinder, a dispensing mechanism, a material hopper and mixing mechanism, a processing mechanism, and a power component. This device thoroughly breaks up clumps of fertilizer and can simultaneously dispense four different fertilizers. The fertilizers are spread evenly in layers before mixing. The device performs both horizontal and vertical mixing and can control the mixing ratio of the fertilizers. The mixing cylinder is fixedly mounted on the base, the material hopper and mixing mechanism are movably mounted in a groove on the mixing cylinder, the dispensing mechanism is fixedly mounted on the material hopper and mixing mechanism, the processing mechanism is fixedly mounted on the material hopper and mixing mechanism, and the power component is fixedly mounted on the material hopper and mixing mechanism. Because this device dispenses materials through individual hoppers and controls the mixing ratio of the fertilizers through the dispensing mechanism, it has drawbacks such as the inability to dispense materials intermittently and insufficient precision in the dispensing ratio. Furthermore, this device cannot solve the problem of pressing samples into flakes. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a pretreatment device for laser-induced breakdown spectroscopy (LAS-PSA) coal powder classification and detection. This device uses a grinding needle to pierce and grind the coal block during rotation, ensuring thorough and uniform refinement. The grinding needle impacts the grinding plate, vibrating and cleaning away residual coal powder, allowing for complete collection of the processed coal powder sample. By incorporating a feeding and stirring mechanism and a briquetting mechanism within the preparation chamber, proportional feeding is achieved, resulting in more rational material release, improved mixing and sample preparation, and ultimately, a sheet-like sample with uniformly fine particles. Therefore, the sheet-like sample used for LAS-PSA coal powder classification and detection features uniformly fine particles, thorough raw material mixing, and excellent preparation results.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection includes a treatment table 1. A refining box 2 and a preparation box 3 are fixedly arranged on the table surface of the treatment table 1. A pushing mechanism 51 penetrating the upper part of the treatment table 1 is arranged in the lower part of the inner side of the refining box 2. A grinding mechanism 50 is arranged above the pushing mechanism 51. A feeding and stirring mechanism 52 is arranged in the upper part of the inner side of the preparation box 3. The discharge port of the feeding and stirring mechanism 52 is connected to the inlet of the pressing mechanism 53 penetrating the table surface of the treatment table 1.

[0008] The pushing mechanism 51 includes a support plate 20 located inside the refining box 2. The lower end of the support plate 20 is fixedly connected to the screw 18. The end of the screw 18 away from the support plate 20 is screwed into the threaded groove of the screw sleeve 16 and can be screwed in and out of the threaded groove. The inner end of the screw 18 away from the support plate 20 is inserted into the driving rod 19 and slidably connected to the driving rod 19. The end of the driving rod 19 away from the support plate 20 is connected to the power input shaft of the displacement motor 15.

[0009] The grinding mechanism 50 includes a refining shaft 5, which is connected to the power output shaft of the refining motor 4. The end of the refining shaft 5 away from the refining motor 4 is connected to the refining plate 6. A groove 7 is provided at the bottom center of the refining plate 6. The inner wall of the groove 7 is connected to the grinding plate 9 by a spring 8. The refining shaft 5 passes through the driving plate 10 and is fixedly connected to the driving plate 10. At least one upper repulsion block 11 is embedded in the driving plate 10. The upper repulsion block 11 is connected to the lower repulsion block 13 by a compression spring 12. A grinding needle 14 is fixedly provided at the lower end of the lower repulsion block 13. The grinding needle 14 passes through the refining plate 6 and the grinding plate 9 and is slidably connected to the refining plate 6 and the grinding plate 9.

[0010] The feeding and mixing mechanism 52 includes a mixing motor 25, the power output shaft of the mixing motor 25 is fixedly connected to the mixing shaft 26, the mixing shaft 26 is fixedly connected to the power input mechanism of the feeding assembly 54, the discharge port of the feeding assembly 54 is connected to the inlet of the mixing assembly 55, and the power input mechanism of the mixing assembly 55 is fixedly connected to the mixing shaft 26.

[0011] The feeding assembly 54 includes symmetrical feeding hoppers 28 located on the left and right sides of the mixing motor 25. The power input mechanism of the feeding assembly 54 includes a drive gear 43 set on the side wall of the mixing shaft 26. The drive gear 43 is meshed with a driven gear 42. The bottom of the driven gear 42 is fixedly connected to the mounting shaft 40. The mounting shaft 40 is embedded in the feeding box 27 and rotatably connected to the upper box of the feeding box 27. A protrusion 41 is fixedly set on the side of the mounting shaft 40 away from the mixing shaft 26. The side of the protrusion 41 away from the mounting shaft 40 is movably connected to a stop block 38. The stop block 38 is fixedly connected to the inner wall of the feeding box 27 by a return spring 37. A through misaligned hole 39 is provided in the middle of the stop block 38. A through discharge port 36 is provided at the bottom of the feeding box 27. The discharge port 36 intermittently coincides with the misaligned hole 39 and the discharge port of the feeding hopper 28.

[0012] The stirring assembly 55 includes a mixing hopper 29, the inlet of which is connected to the outlet 36 of the discharging assembly 54. The bottom of the mixing hopper 29 abuts against the surface of the release plate 44. The release plate 44 is rotatably connected to the power output shaft of the drive motor 45. The drive motor 45 is fixedly installed on the inner wall of the preparation box 3. The power input mechanism of the stirring assembly 55 includes a lead screw 30, which is fixedly connected to the bottom of the mixing shaft 26. A base plate 46 is fixedly provided at the bottom of the lead screw 30. A stirring rod 47 is fixedly provided on the side of the base plate 46 away from the lead screw 30. The base plate 46 is in movable contact with the release plate 44.

[0013] The lead screw 30 is a reciprocating lead screw with a fully closed threaded groove and is threadedly connected to the slider 31. A fan blade 34 is fixedly provided at the end of the slider 31 away from the lead screw 30, and a toggle plate 35 is fixedly provided at the bottom end of the slider 31 away from the lead screw 30.

[0014] The pressing mechanism 53 includes a connecting rod 22, which includes an operating connecting rod 57 and an L-shaped actuating connecting rod 58 connected to one end of the operating connecting rod 57. The other end of the operating connecting rod 57 is fixedly connected to the power output shaft of the hydraulic cylinder 21, which is fixedly connected to the top of the inner side of the processing table 1. A pressure plate 23 is fixedly installed on the other end of the L-shaped actuating connecting rod 58. A pressing box 24 located inside the preparation box 3 is fixedly installed on the table surface of the processing table 1. The area of ​​the upper opening of the pressing box 24 matches the area of ​​the pressure plate 23 located directly above the pressing box 24.

[0015] Both the upper repulsion block 11 and the lower repulsion block 13 are electromagnets, and they repel each other when energized.

[0016] The driving gear 43 is a sector gear.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] 1. Compared with the prior art where the sample is simply refined by grinding balls in the grinding basin, the present invention uses grinding needles to pierce the coal block, and at the same time, the grinding needles collide and cut the coal block during the rotation process, so that the coal block is fully crushed. In addition, the continuous rotational motion during the upward movement of the bearing plate enhances the grinding capacity of the grinding plate and improves the efficiency of coal block refinement.

[0019] 2. In this invention, the grinding needle passes through the refining plate and repeatedly impacts the grinding plate during the random magnetic recovery process, so that the coal powder remaining at the bottom of the grinding plate is vibrated and cleaned, thereby collecting all the fine and uniform coal powder and improving the accuracy of subsequent sample mixing.

[0020] 3. This invention designs two sets of different numbers of teeth on the drive gears to make the material release frequency different. The tooth ratio can be designed according to the proportion to achieve proportional material release, making the material release more reasonable and improving the mixing effect of subsequent samples.

[0021] 4. This invention uses a stirring rod to stir the sample laterally, and utilizes the characteristics of a reciprocating screw to drive a fan blade and a toggle plate fixedly connected to a slider to reciprocate. During the up-and-down reciprocating motion of the fan blade, the airflow direction is changed, causing the airflow inside the mixing hopper to become turbulent, which improves the mixing degree during the powder falling process. This results in multiple mixing of the sample in both the horizontal and vertical directions, and has the characteristic of good mixing effect.

[0022] 5. This invention uses a pressing mechanism to press a uniformly mixed powder sample into a sheet-like sample, thereby meeting the sample preparation requirements for laser-induced breakdown spectroscopy detection of coal powder classification.

[0023] In summary, this invention achieves thorough and uniform finening of the coal lumps by using grinding needles to pierce them and by cutting and grinding them during rotation. The grinding needles also impact the grinding plate, vibrating and cleaning away residual coal powder, ensuring all finely ground coal powder is collected. Furthermore, the inclusion of a feeding and mixing mechanism and a briquetting mechanism within the preparation chamber enables proportional feeding, improving the mixing and sample preparation effect, ultimately resulting in a sheet-like sample with uniformly fine particles. Therefore, the sheet-like sample used for laser-induced breakdown spectroscopy (LAS) for coal powder classification exhibits characteristics of uniformly fine particles, thorough raw material mixing, and excellent preparation results. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection proposed in this invention.

[0025] Figure 2 This is a half-sectional view of a pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection proposed in this invention.

[0026] Figure 3 This is a schematic diagram of the lower half of the refining box in a pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection proposed in this invention.

[0027] Figure 4 This is a schematic diagram of the upper half of the refining box in a pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection proposed in this invention.

[0028] Figure 5 This is a schematic diagram of the upper half of the preparation box in a pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection proposed in this invention.

[0029] Figure 6 This is a schematic diagram of the lower half of the preparation box in a pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection proposed in this invention.

[0030] In the diagram: 1. Processing table; 2. Refining box; 3. Preparation box; 4. Refining motor; 5. Refining shaft; 6. Refining plate; 7. Groove; 8. Connecting spring; 9. Grinding plate; 10. Upper repulsion block; 11. Compression spring; 12. Lower repulsion block; 13. Grinding needle; 14. Displacement motor; 15. Screw sleeve; 16. Relief hole; 17. Screw; 18. Drive rod; 19. Bearing plate; 20. Hydraulic cylinder; 21. L-shaped connecting rod; 22. Pressure plate; 23. Pressure box; 24. Mixing motor; 25. Mixing shaft; 26. Discharge box; 27. Discharge hopper; 28. Mixing hopper; 29. ​​Lead screw; 30. Slider; 3 1. Guide sleeve 32. Spacer sleeve 33. Fan blade 34. Actuating plate 35. Lowering port 36. Return spring 37. Stop block 38. Misalignment hole 39. Mounting shaft 40. Protrusion 41. Passive gear 42. Active gear 43. Release plate 44. Drive motor 45. Base plate 46. Stirring rod 47. First discharge channel 48. Second discharge channel 49. Grinding mechanism 50. Pushing mechanism 51. Discharge and stirring mechanism 52. Pressing mechanism 53. Discharge assembly 54. Stirring assembly 55. Baffle 56. Operating linkage 57. L-shaped action linkage 58. Detailed Implementation

[0031] To more directly demonstrate the purpose, technical solution, and advantages of this invention, the structural principle of this invention will be described in detail below with reference to the accompanying drawings.

[0032] Reference Figure 1 , 2 A pretreatment device for laser-induced breakdown spectroscopy coal powder classification and detection includes a treatment table 1. A refining box 2 and a preparation box 3 are fixedly installed on the upper end of the treatment table 1. A pushing mechanism 51 penetrating the table surface of the treatment table 1 is provided on the lower part of the inner side of the refining box 2. A grinding mechanism 50 is arranged above the pushing mechanism 51. A feeding and stirring mechanism 52 is provided on the upper part of the inner side of the preparation box 3. The discharge port of the feeding and stirring mechanism 52 is connected to the inlet of the pressing mechanism 53 penetrating the table surface of the treatment table 1.

[0033] Reference Figure 3 The pushing mechanism 51 includes a support plate 20 located inside the refining box 2, the lower end of which is fixedly connected to the screw 18; the screw sleeve 16 has a threaded groove inside, and the end of the screw 18 away from the support plate 20 is screwed into the threaded groove of the screw sleeve 16 and can be screwed in and out of the threaded groove; the end of the screw 18 away from the support plate 20 is inserted into the driving rod 19 and is slidably connected to the driving rod 19, the end of the driving rod 19 away from the support plate 20 is connected to the power input shaft of the displacement motor 15, and the driving rod 19 has a square structure; the inner side of the screw sleeve 16 near the end of the displacement motor 15 is provided with a clearance hole 17.

[0034] Reference Figure 4The grinding mechanism 50 includes a refining shaft 5, which is connected to the power output shaft of the refining motor 4. The end of the refining shaft 5 away from the refining motor 4 is connected to the refining plate 6. A groove 7 is provided at the bottom center of the refining plate 6, and four springs 8 are provided inside the groove 7. The inner wall of the groove 7 is connected to the grinding plate 9 through the springs 8. The refining shaft 5 passes through the driving plate 10 and is fixedly connected to the driving plate 10. Eight upper repulsion blocks 11 are embedded at the bottom of the driving plate 10. The upper repulsion blocks 11 are connected to the lower repulsion blocks 13 through compression springs 12. A grinding needle 14 is fixedly provided at the lower end of the lower repulsion block 13. The grinding needle 14 passes through the refining plate 6 and the grinding plate 9 and is slidably connected to the refining plate 6 and the grinding plate 9. Both the upper repulsion blocks 11 and the lower repulsion blocks 13 are electromagnets. When energized, the two repel each other.

[0035] Reference Figure 5 The feeding and mixing mechanism 52 includes a feeding assembly 54 and a mixing assembly 55 connected to the discharge port of the feeding assembly 54. The feeding assembly 54 includes feeding hoppers 28 symmetrically located at the left and right ends of the mixing motor 25. The feeding hoppers 28 include a first feeding channel 48, the discharge port of the first feeding channel 48 and the inlet of a second feeding channel 49 are integrally connected, and the second feeding channel 49 passes through the upper box of the feeding box 27. The power output shaft of the mixing motor 25 is fixedly connected to the mixing shaft 26. A drive gear 43 is provided on the side wall of the mixing shaft 26. The drive gear 43 is a sector gear. The drive gear 43 meshes with the driven gear 42. The bottom of the driven gear 42 The mounting shaft 40 is fixedly connected to the feeding box 27, which is embedded in the feeding box 27 and rotatably connected to the upper box of the feeding box 27. A semi-circular baffle 56 is fixedly installed on the bottom of the feeding box 27 near the mixing shaft 26. A protrusion 41 is fixedly installed on the side of the mounting shaft 40 away from the mixing shaft 26. The side of the protrusion 41 away from the mounting shaft 40 is movably connected to the stop block 38. The stop block 38 is fixedly connected to the inner wall of the feeding box 27 by a return spring 37. A through misaligned hole 39 is provided in the middle of the stop block 38. A through discharge port 36 is provided at the bottom of the feeding box 27. The discharge port 36 intermittently overlaps with the misaligned hole 39 and the discharge port of the second feeding channel 49.

[0036] The stirring assembly 55 includes a mixing hopper 29 embedded in the inner wall of the preparation chamber 3. The mixing hopper 29 is connected to the lower outlet 36 of the discharging assembly 54. The bottom of the mixing hopper 29 abuts against the surface of the release plate 44. The release plate 44 is rotatably connected to the power output shaft of the drive motor 45. The drive motor 45 is fixedly installed on the inner wall of the preparation chamber 3. A lead screw 30 is fixedly installed at the bottom of the mixing shaft 26. The lead screw 30 is a reciprocating lead screw with a fully closed thread groove. A base plate 46 is fixedly installed at the bottom of the lead screw 30. A stirring rod 47 is fixedly installed on the side of the base plate 46 away from the lead screw 30. The base plate 46 and the release plate 44 are connected. 4. Active contact; A metal ring is provided at the bottom of the spacer 33 and the metal ring is connected to the base plate 46 through a bearing. The spacer 33 is made of elastic rubber material. The end of the spacer 33 away from the base plate 46 is movably connected to the bottom of the slider 31. A fan blade 34 is fixedly provided at the end of the slider 31 away from the lead screw 30. A toggle plate 35 is fixedly provided at the bottom of the slider 31 away from the lead screw 30. The slider 31 is threadedly connected to the lead screw 30. A guide sleeve 32 is fixedly provided at the end of the slider 31 away from the base plate 46. The guide sleeve 32 is embedded in the bottom of the discharge box 27 and is slidably connected to the bottom of the discharge box 27. The baffle 56 and the mixing shaft 26 are slidably connected through the guide sleeve 32.

[0037] Reference Figure 6 The pressing mechanism 53 includes a connecting rod 22, which includes an operating connecting rod 57 and an L-shaped actuating connecting rod 58. The operating connecting rod 57 is fixedly connected to the power output shaft of the hydraulic cylinder 21, which is fixedly connected to the top of the inner side of the processing table 1. The operating connecting rod 57 passes through the table surface of the processing table 1 and is slidably connected to the processing table 1. The L-shaped actuating connecting rod 58 is integrally fixedly connected to the end of the operating connecting rod 57 away from the hydraulic cylinder 21. A pressure plate 23 is fixedly installed at the end of the L-shaped actuating connecting rod 58 near the processing table 1. A pressing box 24 located inside the preparation box 3 is fixedly installed on the table surface of the processing table 1. The area of ​​the upper opening of the pressing box 24 matches the area of ​​the pressure plate 23 located directly above the pressing box 24.

[0038] The working principle of this invention is:

[0039] In actual use, the coal block to be processed is placed on the bearing plate 20, the displacement motor 15 is started, and the external power supply continuously supplies power to the repulsion block 11. The displacement motor 15 drives the drive rod 19 to rotate, which in turn drives the screw 18 to rotate. The screw 18 rotates inside the screw sleeve 16, causing it to move upward, thereby driving the bearing plate 20 to rotate upward. At the same time, the refining motor 4 is started, and the power output shaft of the refining motor 4 drives the refining shaft 5 to rotate, which in turn drives the refining plate 6 to rotate. The grinding plate 9 is limited by the grinding needle 14 and rotates synchronously with the refining plate 6. As the coal block on the bearing plate 20 continuously rotates, the refining plate 9 rotates upward. The rotating and rising contact with the grinding needle 14 causes the grinding needle 14 to continuously squeeze the coal block, eventually piercing it. At the same time, the rotation process causes the coal blocks to collide and cut each other, thus crushing the coal blocks. As the coal blocks on the support plate 20 continue to rise, the coal blocks also continuously squeeze the grinding needle 14, thereby continuously reducing the distance between the lower block 13 and the upper block 11, resulting in a continuous strengthening of the magnetic repulsion effect. This gives the grinding needle 14 enough pressure to pierce the coal block, thus crushing it. The continuously rotating and rising support plate 20 forces the crushed coal blocks to be squeezed and ground on the grinding plate 9 to obtain coal powder.

[0040] After grinding is completed, the reverse displacement motor 15 is reversed, and the displacement motor 15 drives the bearing plate 20 to fall back. At the same time, the continuous power supply of the external power supply equipment to the repulsion block 11 is changed to random power supply, so that the power-on and power-off states of the repulsion block 11 occur randomly. When the upper repulsion block 11 is de-energized, the magnetic force between the upper repulsion block 11 and the lower repulsion block 13 disappears. The grinding needle 14 moves upward under the elastic force of the compression spring 12, so that the grinding plate 9 is no longer limited. As a result, the grinding plate 9 and the refining plate 6 are connected only by the connecting spring 8. However, the strength of the connecting spring 8 is limited. During the rotation and descent of the bearing plate 20, the connecting spring 8 will deviate to a certain extent, and the grinding plate 9 and the grinding needle 14 will be misaligned to a certain extent, so that the subsequent grinding needle 14 can no longer accurately pass through the grinding plate 9. When the upper repulsion block 11 is energized, the grinding needle 14 passes through the refining plate 6 and hits the grinding plate 9 under the action of magnetic force. This causes the coal powder residue at the bottom of the grinding plate 9 to be cleaned by vibration, so that all the coal powder is collected, which is convenient for subsequent accurate proportioning and avoids affecting the proportioning quality.

[0041] After the coal lumps are crushed and refined, coal powder and boric acid powder are added to two discharge hoppers 28 according to a certain weight ratio. The mixing motor 25 is started, which drives the mixing shaft 26 to rotate. The mixing shaft 26 drives the drive gear 43 to rotate, which in turn drives the meshing driven gear 42 to rotate. The driven gear 42 drives the mounting shaft 40 to rotate, which in turn drives the protrusion 41 to rotate. The protrusion 41 pushes the stop block 38 to slide back and forth, so that the misaligned hole 39 intermittently overlaps with the discharge port 36 and the discharge port of the discharge hopper 28, thereby intermittently releasing coal powder and boric acid powder. Since the number of teeth of the two sets of drive gears 43 is different, the release frequency of the materials is different. The tooth ratio can be designed according to the ratio to achieve proportional feeding, making the release of materials more reasonable and improving the subsequent mixing effect.

[0042] After the coal powder and boric acid powder are released, they enter the mixing hopper 29. The mixing shaft 26 drives the lead screw 30 to rotate. Utilizing the characteristics of the reciprocating lead screw, the lead screw 30 can drive the slider 31 to move up and down. The slider 31 drives the agitator plate 35 to move up and down. The agitator plate 35 moves the powder up and down, so that the powder can be mixed better. At the same time, the lead screw 30 drives the bottom plate 46 to rotate, which in turn drives the stirring rod 47 to rotate, and mixes the powder laterally. Meanwhile, the slider 31 drives the fan blade 34 to move up and down, changing the airflow direction, making the airflow inside the mixing hopper 29 turbulent, and improving the mixing effect of the powder.

[0043] After the powder mixing is completed, the drive motor 45 is started, and the drive motor 45 drives the release plate 44 to deflect. The mixed powder moves along the release plate 44 into the pressure box 24. Then the hydraulic cylinder 21 is started, and the hydraulic cylinder 21 drives the pressure plate 23 to move downward through the connecting rod 22, pressing the mixed powder into a sheet. Finally, the sheet sample is taken out and transferred to the testing station. The spectrum of the sample is obtained by using a pulsed laser and a spectrometer. The coal powder is classified by analyzing the spectrum of the sample.

Claims

1. A pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection, comprising a processing table (1), wherein a refining box (2) and a preparation box (3) are fixedly arranged on the surface of the processing table (1), characterized in that: The lower part of the inner side of the refining box (2) is provided with a pushing mechanism (51) that penetrates the upper part of the processing table (1); a grinding mechanism (50) is arranged above the pushing mechanism (51); a feeding and stirring mechanism (52) is provided on the upper part of the inner side of the preparation box (3), and the discharge port of the feeding and stirring mechanism (52) is connected to the inlet of the pressing mechanism (53) that penetrates the table surface of the processing table (1); the grinding mechanism (50) includes a refining shaft (5), which is connected to the power output shaft of the refining motor (4), and the end of the refining shaft (5) away from the refining motor (4) is connected to the refining plate (6). A groove (7) is provided at the bottom center of the refining plate (6). The inner wall of the groove (7) is connected to the grinding plate (9) by a connecting spring (8). The refining shaft (5) passes through the driving plate (10) and is fixedly connected to the driving plate (10). At least one upper repulsion block (11) is embedded in the driving plate (10). The upper repulsion block (11) is connected to the lower repulsion block (13) by a compression spring (12). A grinding needle (14) is fixedly provided at the lower end of the lower repulsion block (13). The grinding needle (14) passes through the refining plate (6) and the grinding plate (9) and is slidably connected to the refining plate (6) and the grinding plate (9).

2. The pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 1, characterized in that: The pushing mechanism (51) includes a bearing plate (20) located inside the refining box (2), the lower end of the bearing plate (20) being fixedly connected to the screw (18); the end of the screw (18) away from the bearing plate (20) is screwed into the threaded groove of the screw sleeve (16) and can be screwed in and out of the threaded groove; the inner end of the screw (18) away from the bearing plate (20) is inserted into the driving rod (19) and is slidably connected to the driving rod (19); the end of the driving rod (19) away from the bearing plate (20) is connected to the power input shaft of the displacement motor (15).

3. The pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 1, characterized in that: The feeding and mixing mechanism (52) includes a mixing motor (25), the power output shaft of the mixing motor (25) is fixedly connected to the mixing shaft (26), the mixing shaft (26) is fixedly connected to the power input mechanism of the feeding assembly (54), the discharge port of the feeding assembly (54) is connected to the inlet of the mixing assembly (55), and the power input mechanism of the mixing assembly (55) is fixedly connected to the mixing shaft (26).

4. The pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 3, characterized in that: The feeding assembly (54) includes feeding hoppers (28) symmetrically located on the left and right sides of the mixing motor (25). The power input mechanism of the feeding assembly (54) includes a drive gear (43) disposed on the side wall of the mixing shaft (26). The drive gear (43) meshes with a driven gear (42). The bottom of the driven gear (42) is fixedly connected to the mounting shaft (40). The mounting shaft (40) is embedded in the feeding box (27) and rotatably connected to the upper body of the feeding box (27). The mounting shaft (40) is away from the upper body of the feeding box (27). A protrusion (41) is fixedly provided on one side of the mixing shaft (26). The side of the protrusion (41) away from the mounting shaft (40) is movably connected to the stop block (38). The stop block (38) is fixedly connected to the inner wall of the feeding box (27) by a return spring (37). A through misalignment hole (39) is provided in the middle of the stop block (38). A through discharge port (36) is provided at the bottom of the feeding box (27). The discharge port (36) intermittently overlaps with the misalignment hole (39) and the discharge port of the feeding hopper (28).

5. A pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 3 or 4, characterized in that: The stirring assembly (55) includes a mixing hopper (29), the inlet of the mixing hopper (29) is connected to the outlet (36) of the discharge assembly (54), the bottom of the mixing hopper (29) abuts against the surface of the release plate (44), the release plate (44) is rotatably connected to the power output shaft of the drive motor (45), and the drive motor (45) is fixedly installed on the inner wall of the preparation box (3); the power input mechanism of the stirring assembly (55) includes a lead screw (30), the lead screw (30) is fixedly connected to the bottom of the mixing shaft (26), a base plate (46) is fixedly provided at the bottom of the lead screw (30), and a stirring rod (47) is fixedly provided on the side of the base plate (46) away from the lead screw (30), and the base plate (46) is in movable contact with the release plate (44).

6. The pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 5, characterized in that: The lead screw (30) is a reciprocating lead screw with a fully closed threaded groove and is threadedly connected to the slider (31). A fan blade (34) is fixedly provided at the end of the slider (31) away from the lead screw (30), and a toggle plate (35) is fixedly provided at the bottom of the slider (31) away from the lead screw (30).

7. The pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 1, characterized in that: The pressing mechanism (53) includes a connecting rod (22), which includes an operating connecting rod (57) and an L-shaped action connecting rod (58) connected to one end of the operating connecting rod (57). The other end of the operating connecting rod (57) is fixedly connected to the power output shaft of the hydraulic cylinder (21) fixedly connected to the top of the inner side of the processing table (1). The other end of the L-shaped action connecting rod (58) is fixedly provided with a pressure plate (23). A pressure box (24) located inside the preparation box (3) is fixedly provided on the table surface of the processing table (1). The area of ​​the upper opening of the pressure box (24) matches the area of ​​the pressure plate (23) located directly above the pressure box (24).

8. The pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 1, characterized in that: Both the upper repulsion block (11) and the lower repulsion block (13) are electromagnets, and they repel each other when energized.

9. A pretreatment device for laser-induced breakdown spectroscopy-based coal powder classification and detection according to claim 4, characterized in that: The driving gear (43) is a sector gear.

Images