Safe screening system and process method for dangerous materials

Abstract

The invention discloses a safe screening system and process method for dangerous materials. The safe screening system comprises a two-layer feeding platform and a dust-free feeding bin arranged at the upper end of the two-layer feeding platform. A quantitative feeding mechanism is located on the two-layer feeding platform, a feeding hopper is connected to the lower portion of the dust-free feeding bin, and inner cavities of the feeding hopper and the dust-free feeding bin are communicated. An oversize product collecting tank and an undersize product collecting tank are arranged under an oversize product discharge port and an undersize product discharge port of the screening machine respectively; and the gas replacement device is communicated with the inner cavity of the screening machine and the dust-free feeding bin. Through reasonable arrangement of component structures, the system integrates functional modules of feeding, gas replacement, charging, screening and the like, full-process automatic control is achieved, manual operation links are reduced, labor intensity is reduced, the overall leakproofness of the system is matched, dust pollution is reduced, and the production environment and the health of operators are protected; and meanwhile, production fluctuation caused by manual operation errors is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wheel stopper, and particularly relates to a dangerous material safe screening system and process method. BACKGROUND

[0002] In the fields of chemical industry, medicine and new energy, the screening operation of flammable, explosive and easily oxidized dangerous materials is a key link in the production process, and its safety and efficiency directly determines the stability of the overall production and the product quality. However, the existing dangerous material screening technology still has many problems to be solved, mainly in the following aspects: Firstly, the lack of safety protection is the most prominent problem at present. In the screening process of dangerous materials (such as some metal powders and energetic material particles), if they are fully contacted with oxygen in the air, or static electricity and local high temperature are generated due to screening friction, combustion, explosion and other safety accidents are easily caused. The traditional screening equipment lacks effective gas environment control means, and only relies on simple ventilation or sealing design, which cannot realize the precise regulation of the oxygen content in the screening machine, resulting in high safety hidden danger in the operation process.

[0003] Secondly, the screening efficiency and effect are poor. Dangerous materials often have strong cohesiveness, and the conventional rotary vibrating screen screening device only relies on mechanical vibration to realize material dispersion. For fine powder or particles with strong viscosity, the phenomenon of screen clogging and material accumulation is easy to occur, which not only reduces the screening efficiency, but also leads to the decrease of the separation precision of the oversize and undersize materials, affecting the product quality in the subsequent production link. Part of the equipment tries to introduce auxiliary dispersion means, but the integration degree with the screening system is low, and it is difficult to realize collaborative operation.

[0004] Thirdly, the labor participation is high, and the process automation degree is low. In the traditional screening process, the material feeding relies on manual operation, which not only has high labor intensity, but also increases the risk of direct contact between the operator and the dangerous materials; at the same time, the key process parameters such as the thickness of the oversize material accumulation and the feeding speed rely on manual observation and adjustment, and it is difficult to realize real-time monitoring and accurate control, which is easy to cause production fluctuation or safety problems due to human operation errors.

[0005] In addition, the dust pollution problem is significant. If the dust of dangerous materials leaks in the feeding and screening process, it will not only pollute the production environment, but also harm the health of the operators, and further increase the risk of dust explosion. The sealing performance of the existing feeding bin is insufficient, and there is no effective dust-free treatment mechanism, which is difficult to meet the environmental protection and safety requirements of dangerous material screening. SUMMARY

[0006] In view of the above problems, the purpose of the present application is to provide a dangerous material safe screening system and process, which realizes the whole process precise control of the oxygen content in the screening machine and the material accumulation thickness, improves the material dispersion effect and screening efficiency, reduces the manual participation, and finally achieves the safe, efficient and dust-free operation of the dangerous material screening.

[0007] To achieve the above purpose, the technical solution adopted by the present application includes: A dangerous material safe screening system, which comprises a two-layer feeding platform and a dust-free feeding bin arranged at the upper end of the two-layer feeding platform; further comprises a quantitative safe screening and testing device, the quantitative safe screening and testing device comprising a quantitative feeding mechanism and a rotary vibration screening mechanism; the quantitative feeding mechanism comprises a feeding hopper and an inclined chute, the inclined chute is a hollow cylinder as a whole, and its axis is inclined to the horizontal plane, the inlet of the inclined chute is located on the side wall close to one end of the inclined chute and opens upward to communicate with the outlet of the feeding hopper, and the outlet of the inclined chute is located on the side wall close to the other end of the inclined chute and is opposite to the inlet; the rotary vibration screening mechanism comprises a screening machine, and the outlet of the inclined chute communicates with the feeding port of the screening machine; the quantitative feeding mechanism is located on the two-layer feeding platform, the feeding hopper is connected to the lower part of the dust-free feeding bin and the inner cavities of the two are communicated; a sieve-on material collecting tank and a sieve-under material collecting tank are respectively arranged below the sieve-on material discharge port and the sieve-under material discharge port of the screening machine; further comprising a gas replacement device which communicates with the inner cavities of the screening machine and the dust-free feeding bin.

[0008] Preferably, the outlet of the feeding hopper and the inlet of the inclined chute are communicated through a first anti-static soft connection, and the outlet of the inclined chute and the feeding port of the screening machine are communicated through a second anti-static soft connection; a pneumatic pipe clamp valve is further arranged between the outlet of the feeding hopper and the first anti-static soft connection.

[0009] Preferably, a pneumatic knocking hammer is arranged on the outer wall of the cone body of the feeding hopper, and a vibration exciter is arranged on the lower side wall close to one end of the inclined chute.

[0010] Preferably, the inclination angle of the inclined chute is 2-15°.

[0011] Preferably, an ultrasonic generating mechanism is arranged on the screen frame of the screening machine.

[0012] Preferably, an acceleration sensor and a non-contact electrostatic voltage sensor are arranged on the upper part of the cover of the screening machine, and a first contact electrostatic voltage sensor and a second contact electrostatic voltage sensor are respectively arranged on the sieve-on material discharge port and the sieve-under material discharge port of the screening machine.

[0013] Preferably, a baffle plate is arranged on the inner measurement of the sieve-on material discharge port of the screening machine, and the opening extension direction of the baffle plate is the same as the positive rotation direction of the screen frame of the screening machine.

[0014] Preferably, the driving of the screening machine is an explosion-proof servo motor, and the screen mesh in the screening machine is a brass screen mesh.

[0015] Preferably, the gas replacement device comprises a nitrogen generator and two groups of gas conveying pipes connected with the nitrogen generator, one group of the gas conveying pipes being communicated with the inner cavity of the screening machine, and the other group of the gas conveying pipes being communicated with the inner cavity of the dust-free feeding bin; the inner cavity of the screening machine and the inner cavity of the dust-free feeding bin are both provided with oxygen content sensors.

[0016] A process method for safe screening of dangerous materials based on the safe screening system for dangerous materials disclosed in the present application, specifically comprising the following steps: Step one, the dangerous materials are added into the bin through the dustproof feeding port of the dust-free feeding bin, after closing the feeding port, the gas replacement device is started to fill inert gas into the inner cavity of the screening machine and the dust-free feeding bin to replace the internal oxygen, and when the oxygen content is reduced to the preset safety standard, the gas replacement device is closed; Step two, the ultrasonic generating mechanism and the motor of the screening machine are started to make high-frequency vibration act on the screen in the screening machine; at the same time, the pneumatic knocking hammer and the exciter are started to quantitatively convey the materials in the dust-free feeding bin to the screening machine according to the preset feeding speed and total amount; Step three, after the materials enter the screening machine, they are quickly dispersed and classified on the screen under the synergistic action of mechanical vibration and ultrasonic vibration; the required particles with a particle size smaller than the screen aperture are discharged from the undersize discharge port and collected by the undersize collection tank, and the impurities with a particle size larger than the screen aperture are discharged from the oversize discharge port and collected by the oversize collection tank, and the oversize accumulation state in the screen is monitored in real time through the material accumulation thickness sensor during the process, and when the accumulation thickness exceeds the preset value, the automatic feeding speed can be adjusted or the power of the ultrasonic generating mechanism can be increased for processing; Step four, after the screening operation is completed, the pneumatic knocking hammer and the exciter are closed, the motor of the screening machine and the ultrasonic generating mechanism are closed after the materials in the screening device are basically discharged, and finally the inert gas is continuously introduced into the inner cavity of the screening machine through the gas replacement device for a period of time to blow and clean the inside of the screening machine, so as to ensure that there is no dangerous material residue.

[0017] Compared with the prior art, the advantages of the present application are: (1) The safe screening system and process method for dangerous materials of the present application realize full-process automatic control, reduce manual operation links, reduce labor intensity, reduce dust pollution, protect the production environment and the health of the operators, and avoid production fluctuations caused by human operation errors, through the reasonable setting of the component structure, the system integrates the functions of feeding, gas replacement, feeding, screening and other function modules.

[0018] (2) The application discloses a dangerous material safety screening system and process method, which realizes accurate control of oxygen content in the system through a gas replacement device, effectively avoids the combustion and explosion risk caused by the contact between dangerous materials and oxygen, and reduces the direct contact between operators and dangerous materials through a remote control mode, so that the safety hidden danger is further reduced.

[0019] (3) The application discloses a dangerous material safety screening system and process method, which realizes rapid dispersion of agglomerated materials through the cooperation of an ultrasonic generating mechanism, a pneumatic knocking hammer and a vibration exciter, prevents the clogging of a screen, greatly improves the material dispersion effect and screening efficiency, realizes quantitative feeding, cooperates with the thickness monitoring of the material on the screen, ensures the stability of the screening process, and improves the separation precision. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings are used to provide further understanding of the application and constitute a part of the specification, and are used to explain the application together with the specific embodiments below, but do not constitute a limitation to the application. In the drawings: Figure 1 It is a structural schematic diagram of the dangerous material safety screening system of the application; Figure 2 It is a structural schematic diagram of the quantitative safety screening and testing device in the application; Figure 1 Figure 3 It is a structural schematic diagram of the quantitative feeding mechanism in the application; Figure 2 Figure 4 It is a structural schematic diagram of the screen in the application; Figure 2 Figure 5 It is a structural schematic diagram of the material blocking plate of the material outlet on the screen in the application. Figure 4

[0021] The various reference numerals in the drawings represent: A two-layer feeding platform, B dust-free feeding bin, C quantitative safety screening and testing device, D gas replacement device, E screen material collecting tank, F screen material collecting tank; 1-feeding hopper, 2-pneumatic knocking hammer, 3-pneumatic pipe clamp valve, 4-first anti-static soft connection, 5-vibration exciter, 6-inclined chute, 7-screen upper cover observation window, 8-feeding port, 9-acceleration sensor, 1001-non-contact electrostatic voltage sensor, 1002-first contact type electrostatic voltage sensor, 1003-second contact type electrostatic voltage sensor, 11-ultrasonic generating mechanism, 12-screen material outlet 12, 13-screen material outlet, 14-material blocking plate. DETAILED DESCRIPTION

[0022] ​​​​The application is not limited to the following specific embodiments, and any equivalent variations made on the basis of the technical solutions of the application fall within the protection scope of the application.

[0023] It should be noted that the directional terms mentioned herein are consistent with the specific directions on the paper of the drawings or the corresponding directions of the space shown in the drawings; all components and devices in the application, unless otherwise specified, all use the components and devices known in the prior art.

[0024] Embodiment 1 A dangerous material safety screening system, comprising a two-layer feeding platform A and a dust-free feeding bin B arranged at the upper end of the two-layer feeding platform A; further comprising a quantitative safety screening and testing device C, the quantitative safety screening and testing device comprising a quantitative feeding mechanism and a rotary vibration screening mechanism; the quantitative feeding mechanism comprises a feeding hopper 1 and an inclined chute 6, the inclined chute 6 is a hollow cylinder as a whole, and its axis is inclined to the horizontal plane, the inlet of the inclined chute 6 is located on the side wall close to one end and opens upward to communicate with the outlet of the feeding hopper 1, and the outlet of the inclined chute 6 is located on the side wall close to the other end and is opposite to the inlet; the rotary vibration screening mechanism comprises a screening machine, and the outlet of the inclined chute 6 communicates with the feeding port 8 of the screening machine; the quantitative feeding mechanism is located on the two-layer feeding platform A, and the feeding hopper 1 is connected to the lower part of the dust-free feeding bin B and the inner cavities of the two are communicated; a sieve-on material collecting tank E and a sieve-under material collecting tank F are respectively arranged directly below the sieve-on material discharge port 12 and the sieve-under material discharge port 13 of the screening machine; further comprising a gas replacement device D communicating with the inner cavities of the screening machine and the dust-free feeding bin B; The function is: through the dust-free feeding bin B, the material is added into the feeding hopper 1 of the quantitative safety screening and testing device C, the material is continuously and uniformly fed to the feeding port 8 of the screening machine through the feeding hopper 1 and the inclined chute 6 in sequence, and the sieve-on material and the sieve-under material after screening are collected by the sieve-on material collecting tank E and the sieve-under material collecting tank F respectively; at the same time, through the gas replacement device D, the oxygen content in the system is precisely controlled, and the risk of combustion and explosion caused by the contact between the dangerous material and oxygen is effectively avoided; at the same time, the dust-free feeding bin B adopts a sealed structure design, a feeding port is arranged on the side, the sealed design effectively prevents dust leakage during the feeding process, cooperates with the overall airtightness of the system, reduces dust pollution, and protects the production environment and the health of the operators; the system integrates the functions of feeding, gas replacement, feeding, screening and other function modules, realizes full-process automatic control, reduces manual operation links, reduces labor intensity, and avoids production fluctuations caused by human operation errors.

[0025] The embodiment can adopt a remote control mode to reduce the direct contact between the operators and the dangerous materials, and further reduce the safety hazards.

[0026] The screening machine of the embodiment selects a rotary vibration screening machine.

[0027] The outlet of the feeding hopper 1 of the embodiment is communicated with the inlet of the inclined chute 6 through the first anti-static soft connection 4, the outlet of the inclined chute 6 is communicated with the feeding port 8 of the screening machine through the second anti-static soft connection, the first anti-static soft connection 4 and the second anti-static soft connection are both selected to be electrostatic conductive rubber pipes, and the two ends of the electrostatic conductive rubber pipes are fixed by stainless steel clamps; a pneumatic pipe clamp valve 3 is further arranged between the outlet of the feeding hopper 1 and the first anti-static soft connection 4, and the valve in contact with the material is the pneumatic pipe clamp valve 3.

[0028] The outer wall of the cone body of the feeding hopper 1 of the embodiment is provided with a pneumatic knocking hammer 2 for preventing the bridging of the material in the hopper, the frequency of the pneumatic knocking hammer 2 is 10-30 times per minute, and the pressure is 0.3-0.8 MPa; the lower side wall of the inclined chute 6 close to one end thereof is provided with a vibration exciter 5, and the above connection modes can be welded / riveted; the inclination angle of the inclined chute 6 of the embodiment is 2-15°, and is preferably 5°, which meets the requirement of continuously and uniformly feeding the material to the feeding port 8 of the screening machine under the vibration of a specific frequency and amplitude.

[0029] The screening machine of the embodiment is provided with an ultrasonic generating mechanism 11 on the screen frame, the 35 kHz mechanical wave generated by the ultrasonic generating mechanism 11 is transmitted to the screen through the net frame, the material above the screen is quickly dispersed to avoid clumping, the screening efficiency is improved, and the accumulation of static electricity is reduced.

[0030] The whole can quickly disperse the agglomerated material through the synergistic effect of the ultrasonic generating mechanism 11, the pneumatic knocking hammer 2 and the vibration exciter 5, prevent the screen from being blocked, greatly improve the material dispersion effect and the screening efficiency; the quantitative safe screening and testing device C realizes quantitative feeding, the optical sensor is installed on the screen frame of the screening machine for observing the thickness of the material on the screen, and cooperates with the monitoring of the thickness of the material on the screen in the screening machine to ensure the stability of the screening process and improve the separation precision.

[0031] The drive of the screening machine of the embodiment is an explosion-proof servo motor, the motor meets the requirement of real-time adjustment of the rotation speed of 0-3000 rpm, and can realize online adjustment of the screening frequency. The screen in the screening machine is a brass screen, the static electricity generated by the friction between the material and the screen can be conducted to the grounding device in real time, the accumulation of static electricity is avoided from the source, and the high potential formed by the accumulation of static electricity is avoided; in addition, brass is a non-ferromagnetic material, and the brass screen can be used for screening of materials sensitive to magnetism such as semiconductor materials; the static voltage sensor on the cover of the screen frame and the feeding and discharging ports can monitor the accumulation of static electricity in real time, forming a double safety guarantee, greatly reducing the flash explosion risk in the screening process of flammable and explosive materials, and improving the production safety.

[0032] The inner circumferential surface of the material outlet 12 of the screening machine of the embodiment is welded with a baffle plate 14, and the opening extension direction of the baffle plate 14 is the same as the forward rotation direction of the screen frame of the screening machine. Figure 4As shown, when the motor drives the screen frame to rotate forward, the material above the screen does not discharge, and when the motor reverses, the material on the screen is discharged from the discharge port 12.

[0033] The upper cover of the screen machine is provided with an acceleration sensor 9 and a non-contact electrostatic voltage sensor 1001, and the screen machine is provided with a first contact electrostatic voltage sensor 1002 and a second contact electrostatic voltage sensor 1003 at the screen material discharge port 12 and the undersize material discharge port 13 respectively. The acceleration sensor 9 is used to monitor the vibration amplitude and frequency of the screen machine under different process parameters, and each electrostatic voltage sensor is used to monitor the static electricity accumulation generated by the friction of the material under different process parameters. When in use, the static voltage changes obtained by the three position electrostatic voltage sensors are compared to guide the safety control of the screening process.

[0034] The gas replacement device D of the embodiment includes a nitrogen generator and two groups of gas conveying pipelines connected with the nitrogen generator. One group of gas conveying pipelines is in communication with the inner cavity of the screen machine, and the other group of gas conveying pipelines is in communication with the inner cavity of the dust-free feeding bin B. The internal air is replaced, and the inner cavities of the screen machine and the dust-free feeding bin B are both provided with oxygen content sensors to ensure that they are maintained within the safe standard range.

[0035] Embodiment 2 The process method for safe screening of dangerous materials of the embodiment is based on the system for safe screening of dangerous materials of embodiment 1, and specifically includes the following steps: Step one, feeding and gas replacement: the operator adds 50 kg of aluminum powder into the dust-free feeding bin B through the dust-free feeding port of the dust-free feeding bin B, closes the feeding port, and then remotely starts the gas replacement device D to fill inert gas into the screen machine and the dust-free feeding bin B to replace the internal oxygen; the oxygen content in the system is monitored in real time through the oxygen content monitoring sensor, and the gas replacement is stopped when the oxygen content is reduced to 2%.

[0036] Step two, start the screening system: remotely start the ultrasonic generating mechanism 11 and the motor of the screen machine, set the power of the ultrasonic generating mechanism 11 to 200 W so that it generates high-frequency vibration acting on the screen in the screen machine; at the same time, start the pneumatic knocking hammer 2 and the exciter 5, and set the feeding speed to 80 kg / h to quantitatively convey the material in the dust-free feeding bin B into the screen machine.

[0037] Step three, material screening and discharge: after the material enters the screen machine, it is quickly scattered and classified on the screen surface under the synergistic action of mechanical vibration and ultrasonic vibration; the required particles with a particle size smaller than the screen mesh aperture are discharged from the undersize material discharge port 13 and collected in the undersize material collection tank F, and the impurities (oversize material) with a particle size larger than the screen mesh aperture are discharged from the oversize material discharge port 12 and collected in the oversize material collection tank E; during the process, the oversize material accumulation state is monitored in real time through the material accumulation thickness sensor, and when the accumulation thickness exceeds the preset value, the power of the ultrasonic generating mechanism 11 is increased to 400 W.

[0038] Step four, job end and cleaning: after the screening job is completed, first close the pneumatic hammer 2 and the exciter 5, and then close the motor of the screening machine and the ultrasonic generating mechanism 11 after the material in the screening machine is basically discharged; finally, the inert gas is continuously introduced into the screening machine through the gas displacement device D for a period of time to blow and clean the inside of the system to ensure that there is no dangerous material residue.

[0039] The preferred embodiments of the present disclosure are described in detail above in combination with the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Within the technical concept range of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection range of the present disclosure.

[0040] In addition, it should be noted that various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combination manners.

[0041] In addition, various different embodiments disclosed in the present solution can also be combined in any manner as long as they do not deviate from the idea of the present disclosure, and they should also be considered as the content invented by the present disclosure.

Claims

1. A safety screening system for hazardous materials, characterized in that, It comprises a two-layer feeding platform (A) and a dust-free feeding bin (B) arranged at the upper end of the two-layer feeding platform (A); It also comprises a quantitative safety screening and testing device (C) which comprises a quantitative feeding mechanism and a rotary vibration screening mechanism; the quantitative feeding mechanism comprises a feeding hopper (1) and an inclined chute (6), the inclined chute (6) is a hollow cylinder as a whole, the axis of which is inclined to the horizontal plane, the inlet of the inclined chute (6) is located on the side wall close to one end and opens upward to communicate with the outlet of the feeding hopper (1), and the outlet of the inclined chute (6) is located on the side wall close to the other end and is opposite to the inlet; the rotary vibration screening mechanism comprises a screening machine, the outlet of the inclined chute (6) communicates with the feeding port (8) of the screening machine; the quantitative feeding mechanism is arranged on the two-layer feeding platform (A), and the feeding hopper (1) is connected to the lower part of the dust-free feeding bin (B) and the inner cavities of the two are communicated; The screening machine is provided with a sieve-on material collecting tank (E) and a sieve-under material collecting tank (F) below the sieve-on material discharge port (12) and the sieve-under material discharge port (13) of the screening machine, respectively; It also comprises a gas replacement device (D) which communicates with the inner cavity of the screening machine and the inner cavity of the dust-free feeding bin (B).

2. The hazardous material safety screening system as claimed in claim 1, wherein, The outlet of the feeding hopper (1) communicates with the inlet of the inclined chute (6) through a first anti-static soft connection (4), and the outlet of the inclined chute (6) communicates with the feeding port (8) of the screening machine through a second anti-static soft connection; A pneumatic pipe clamp valve (3) is further arranged between the outlet of the feeding hopper (1) and the first anti-static soft connection (4).

3. The hazardous material safety screening system of claim 2, wherein, A pneumatic knocking hammer (2) is arranged on the outer wall of the cone of the feeding hopper (1), and an exciter (5) is arranged on the lower side wall close to one end of the inclined chute (6).

4. The hazardous material safety screening system of claim 3, wherein, The inclination angle of the inclined chute (6) is 2-15°.

5. The hazardous material safety screening system as defined in claim 4, wherein, An ultrasonic generating mechanism (11) is arranged on the screen frame of the screening machine.

6. The hazardous material safety screening system as defined in claim 5, wherein, An acceleration sensor (9) and a non-contact electrostatic voltage sensor (1001) are arranged on the upper part of the upper cover of the screening machine, and a first contact electrostatic voltage sensor (1002) and a second contact electrostatic voltage sensor (1003) are arranged on the sieve-on material discharge port (12) and the sieve-under material discharge port (13) of the screening machine, respectively.

7. The hazardous material safety screening system as defined in claim 6, wherein, A baffle plate (14) is arranged on the inner wall of the sieve-on material discharge port (12) of the screening machine, and the opening of the baffle plate (14) extends in the same direction as the forward rotation direction of the screen frame of the screening machine.

8. The hazardous material safety screening system of claim 7, wherein, The driving of the screening machine is an explosion-proof servo motor, and the screen mesh in the screening machine is a brass screen mesh.

9. A hazardous material safety screening system as claimed in any one of claims 1 to 8, wherein, The gas replacement device (D) comprises a nitrogen generator and two groups of gas conveying pipelines connected with the nitrogen generator, one group of gas conveying pipelines communicates with the inner cavity of the screening machine, and the other group of gas conveying pipelines communicates with the inner cavity of the dust-free feeding bin (B). The inner cavities of the screening machine and the dust-free feeding bin (B) are both provided with an oxygen content sensor.

10. A process for the safe screening of hazardous materials, characterized in that, The dangerous material safety screening system based on claim 9 specifically comprises the following steps: Step one, the dangerous material is added into the dust-free feeding bin (B) through the dust-free feeding port, after the feeding port is closed, the gas replacement device (D) is started, inert gas is filled into the inner cavities of the screening machine and the dust-free feeding bin (B) to replace the internal oxygen, when the oxygen content is reduced to the preset safety standard, the gas replacement device (D) is closed; Step two, open the ultrasonic generator (11) and sieve machine motor, so that it produces high frequency vibration effect on the screen in the sieve machine; at the same time, start the pneumatic hammer (2) and exciter (5), according to the preset feeding speed and total amount, the material in the dust-free feeding bin (B) is quantitatively conveyed to the sieve machine; Step three, under the synergistic effect of mechanical vibration and ultrasonic vibration, the material is quickly dispersed and classified on the screen; the required particles with particle size smaller than the screen aperture are discharged from the undersize discharge port (13) and collected by the undersize collection tank (F), and the impurities with particle size larger than the screen aperture are discharged from the oversize discharge port (12) and collected by the oversize collection tank (E), and the accumulation state of the oversize material in the screen is monitored in real time by the material accumulation thickness sensor during the process, when the accumulation thickness exceeds the preset value, the automatic feeding speed can be adjusted or the power of the ultrasonic generator (11) can be increased for processing; Step four, after the screening operation is completed, first close the pneumatic hammer (2) and exciter (5), and then close the sieve machine motor and ultrasonic generator (11) after the material in the sieve machine is basically discharged, and finally blow inert gas into the sieve machine cavity for a period of time through the gas displacement device (D) to clean the inside of the sieve machine, so as to ensure that there is no dangerous material residue.

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