Multi-mode stone-crushing and screening system with ultrasonic wave and auxiliary vibration

Abstract

The application discloses a multi-mode gravel vibrating screen system with ultrasonic wave cooperation and auxiliary excitation, which comprises a rack, a screen box arranged on the rack, a vibrating screen motor arranged on the screen box, a screen mesh arranged in the screen box and used for conveying and vibrating the gravel, a feeding conveying belt connected with a feeding inlet of the screen box, a coarse aggregate conveying belt connected with a coarse aggregate outlet of the screen mesh, and a fine aggregate conveying belt connected with a fine aggregate outlet of the screen mesh, characterized in that the multi-mode gravel vibrating screen system further comprises an ultrasonic transducer assembly, a left aggregate reflection assembly, a right aggregate reflection assembly, a fine aggregate weighing sensor, a coarse aggregate weighing sensor and a vibrating screen analysis control module. The ultrasonic transducer is used for emitting ultrasonic waves with changeable incident directions, and the ultrasonic waves are reflected by the reflection camber surface and the aggregate plate wheel, so that the effect of the ultrasonic waves on the screen mesh is improved. The multi-mode gravel vibrating screen system can automatically switch among a normal working mode, an ultrasonic wave excitation working mode and an ultrasonic wave cleaning working mode, and can realize continuous, stable and efficient operation of the vibrating screen system.

Description

Technical Field

[0001] This invention relates to an engineering stone crushing and screening system, specifically to a multi-mode stone crushing and screening system with ultrasonic-assisted vibration. Background Technology

[0002] In the field of infrastructure project construction, using self-produced rubble for crushing is a common on-site material production and supply method. Because the reserves of self-produced rubble are relatively small compared to large-scale crushing mines, and production is highly mobile, the investment in building self-produced crushing aggregate production lines is relatively small, and the technical standards are relatively low. To reduce production costs, the rubble raw materials, production lines, and finished product warehouses used in self-produced crushing aggregate production lines are often stored in the open air without rain protection and drying functions, resulting in high moisture content in the rubble raw materials and crushed aggregate mixture. Even worse, to improve the cleanliness of manufactured sand, some production lines use wet production processes, resulting in even higher moisture content in the manufactured sand.

[0003] During vibrating screening, fine aggregates such as manufactured sand, stone powder, and stone chips often agglomerate due to their high moisture content and surface tension and capillary effect, clogging the screen holes. This prevents some fine aggregates that should pass through the screen from doing so, causing them to mix with coarse aggregates (4.75-9.5mm) and be directly transported out by the same-stage belt conveyor. This results in:

[0004] (1) The coarse aggregate with a diameter of 4.75-9.5mm has excessive powder content and increased fine particle ratio, resulting in poor gradation curve and affecting the workability of concrete.

[0005] (2) Fine aggregates with a fineness modulus of less than 4.75mm have a coarse gradation curve, which affects the workability of concrete.

[0006] (3) Low production efficiency, requiring frequent shutdowns to clean the screen.

[0007] On the other hand, because wet aggregates frequently clog the screens, resulting in low screening efficiency and poor screening effect, production line managers often control the screen aperture size of the smallest screen to 4.5mm, i.e., reducing the probability of wet aggregate clogging by increasing the screen aperture size. However, while increasing the screen size can reduce the frequency of downtime for screen cleaning, it also has the following disadvantages:

[0008] (1) This further leads to an increase in the proportion of coarse particles in fine aggregates below 4.75mm, poor gradation curve, and deterioration of the workability of fine aggregates.

[0009] (2) This increases the proportion of coarse particles in the 4.75-9.5mm coarse aggregate, resulting in a poor gradation curve and affecting the workability of concrete.

[0010] Currently, similar phenomena exist in the production of manufactured sand for engineering projects across the country, including some commercially available manufactured sand from mineral deposits. This results in a generally coarser fineness modulus and poor gradation curves in manufactured sand, failing to meet the requirements for medium sand in Zone II. This further leads to deterioration in concrete workability, increased difficulty in adjusting and controlling mix proportions, increased dosage of cementitious materials such as cement, and higher requirements for admixtures, thus significantly increasing the cost of concrete.

[0011] During the crushing process, screen clogging is caused by a variety of factors. Generally, it is due to irregular shape of the stone, a large number of flaky particles or particles at the mesh opening, the thickness of the screen wire, the shape of the mesh opening, and the high moisture content of the material, which cause the crushed stone to get stuck in the screen opening and be difficult to remove. In this case, common cleaning methods include impact cleaning, high-pressure water flushing, and ultrasonic cleaning.

[0012] The impact method typically involves bouncing balls striking the screen to vibrate it, causing particles stuck in the screen holes to dislodge and resolve clogging issues. However, this method often suffers from complex structures or the impact mechanism being located below the screen, obstructing material flow. Furthermore, bouncing balls require a sealed space and are generally suitable for lightweight, fine vibrating screens such as rotary vibrating screens. Sand and gravel screening typically uses large, linear vibrating screens with inclined screens. Using bouncing balls in such cases would cause them to accumulate at the lower end of the screen due to gravity, making it difficult to maintain a clean upper screen.

[0013] High-pressure water cleaning utilizes the high impact force of a high-pressure water stream to remove blockages from the screen mesh. It also removes stains and oxides from the screen surface, restoring its original filtration performance. High-pressure water cleaning is effective for materials with small particles, high moisture content, and good adhesion, but it is limited to wet-process manufactured sand production and is not suitable for dry processes. Furthermore, the wash water contains a large number of suspended solid particles, and direct discharge would create significant environmental problems, requiring additional wastewater treatment measures and increasing production costs.

[0014] Ultrasonic cleaning methods have the advantages of simple structure and no obstruction of materials; however, existing ultrasonic cleaning methods also have some drawbacks. For example, Chinese patent (CN205463180U) discloses a dual-frequency vibrating screen for cleaning screens, and Chinese patent (CN208288410U) discloses a screening device combining ultrasound and vibration. Both methods aim to prevent material from clumping on the screen to solve the problem of screen blockage. However, because the direction of ultrasonic waves and air vibration is parallel to the screen surface, the resulting screen vibration effect is poor, making it difficult to remove material blocking the screen holes, resulting in poor cleaning effect. Another example is Chinese patent (CN220004873U), which discloses an ultrasonic vibrating screen that facilitates the inspection of screen blockage. It uses ultrasound to vibrate the screen, which has a certain anti-blocking effect, but its fundamental function is as a vibrator for the screen. On the one hand, vibrating the screen with ultrasound requires high-energy sound waves, resulting in high energy consumption, which is not conducive to energy conservation and environmental protection; on the other hand, the cleaning effect of the ultrasonic device as a vibrator on the screen is negligible.

[0015] Current ultrasonic cleaning applications for screen cleaning convert 220V, 50Hz or 110V, 60Hz electrical energy into 38kHz high-frequency electrical energy, input into an ultrasonic transducer, and transform it into 38kHz mechanical vibration, thereby achieving efficient screening and screen cleaning. Additionally, sound waves exhibit reflection. When ultrasonic waves propagate from one medium to another, at the interface between the two media, a portion of the energy is reflected back into the original medium, called a reflected wave. The change in the acoustic energy of the reflected wave is closely related to the acoustic impedance of the two media. Suppose a wave is incident from medium 1 (acoustic impedance Z1) to medium 2 (acoustic impedance Z2). When Z1 is much larger than Z2, the sound pressure (sound intensity) is almost completely reflected, and the transmittance tends to 0, such as at a steel-air interface. Sound reflection follows the law of reflection, similar to the principle of light focusing. When the incident sound wave encounters a concave parabolic reflector, the reflected sound will concentrate, forming sound focusing. Sound energy is a type of energy that exists in the form of mechanical waves and phonons. The mechanical waves of sound energy are vibration waves. When sound waves propagate in the air, they cause the air to vibrate, which in turn causes the substances in the air to undergo reciprocating motion along with the air vibration. Summary of the Invention

[0016] To address the aforementioned problems, the present invention aims to provide a multi-mode crushing and screening system with ultrasonic-assisted vibration. This invention utilizes an ultrasonic transducer to emit ultrasonic waves with a variable incident direction. Through the interaction of a reflective arc surface and a rotating aggregate plate, the ultrasonic waves are reflected and focused without affecting the material's descent, thus improving the effect of the ultrasonic waves on the screen. Furthermore, this invention uses a weighing sensor to monitor the ratio of coarse to fine aggregates after screening. The system's operating mode can be intelligently adjusted and controlled via a screening analysis and control module, automatically switching between normal operating mode, ultrasonic vibration mode, and ultrasonic cleaning mode. This ensures continuous, stable, and efficient operation of the screening system while maintaining screening effectiveness.

[0017] The present invention is achieved through the following technical solution.

[0018] A multi-mode crushing and screening system with ultrasonic-assisted vibration includes a frame, a screen box mounted on the frame, a vibrating motor mounted on the screen box, a screen mesh inside the screen box for conveying and screening crushed stone, a feed conveyor belt connected to the feed inlet of the screen box, a coarse aggregate conveyor belt connected to the coarse aggregate outlet of the screen mesh, and a fine aggregate conveyor belt connected to the fine aggregate outlet of the screen mesh. The system is characterized by further including: an ultrasonic transducer assembly, a left aggregate reflector assembly and a right aggregate reflector assembly symmetrically arranged at the bottom of the screen mesh with the screen mesh centerline as the axis, a fine aggregate weighing sensor, a coarse aggregate weighing sensor, and a vibration analysis and control module.

[0019] The ultrasonic transducer assembly includes multiple vertical ultrasonic transducers disposed at the top of the sieve box and capable of rotating along the length of the sieve in a plane perpendicular to the sieve surface to change the ultrasonic incident direction, and multiple horizontal ultrasonic transducers disposed on both sides of the sieve box and capable of rotating along the length of the sieve in a plane parallel to the sieve surface to change the ultrasonic incident direction.

[0020] Both the left and right aggregate reflective components include an aggregate plate arranged along the length of the screen and a reflective arc surface arranged along the length of the screen, which is opposite to the aggregate surface of the aggregate plate. The reflective arc surfaces and the aggregate plate on the left and right sides can rotate tangentially around an axis parallel to the length of the screen, and the two ends of the arc surface of the reflective arc surface are located on their respective rotation surfaces, and the two ends of the aggregate plate are located within their respective rotation surfaces.

[0021] The coarse aggregate weighing sensor and the fine aggregate weighing sensor are respectively installed on the coarse aggregate conveyor belt and the fine aggregate conveyor belt, and are used to weigh the coarse aggregate conveyed on the coarse aggregate conveyor belt and the fine aggregate conveyor belt synchronously at intervals t, and send the coarse aggregate weighing value and the fine aggregate weighing value to the screening performance analysis module.

[0022] The vibrating screen analysis and control module includes:

[0023] It is used to issue a start command to control the feeding of the feed conveyor belt, and to issue a stop excitation command to stop the horizontal ultrasonic transducer and the vertical ultrasonic transducer from working. At the same time, it issues a collection command to rotate the collection plates on the left and right sides to the point where the two are connected to form an inverted V-shape and the feed inlet points to the screen, so that the system is in normal working mode.

[0024] The auxiliary excitation command is used to make the horizontal and vertical ultrasonic transducers emit ultrasonic waves with an incident angle of obtuse angle to the length of the screen, which act on the crushed stone material on the screen. At the same time, the collection command is issued to make the collection plates on the left and right sides rotate until they are connected to form an inverted V-shape and the inlet points to the collection port of the screen, so that the system is in ultrasonic excitation working mode.

[0025] It is used to issue a stop command to control the feed conveyor to stop feeding, and at the same time issue an auxiliary cleaning command to make the horizontal ultrasonic transducer and the vertical ultrasonic transducer emit ultrasonic waves with an incident angle perpendicular to the length direction of the screen and act on the screen. It also issues a reflection command to make the reflection arc surfaces on the left and right sides rotate to a position where the two are tangent and connected and the arc surfaces face the screen, so that the system is in ultrasonic cleaning working mode.

[0026] This is used to identify the current operating mode of the system and receive the weighing values ​​of coarse and fine aggregates under the current operating mode to calculate the real-time ratio k between the two. When the weighing values ​​of coarse and / or fine aggregates are 0, the real-time ratio k is 0. Then, the real-time ratio k is compared with a set threshold l. If the current operating mode is normal operating mode, when k > l, an auxiliary excitation command and an aggregate command are issued to switch the system to the excitation operating mode. When k ≤ l, the current operating mode is maintained. If the current operating mode is ultrasonic excitation operating mode, when k > l, a stop command, an auxiliary cleaning command, and a reflection command are issued to switch the system to the ultrasonic cleaning operating mode. When k ≤ l, the current operating mode is maintained. If the system is running or the current operating mode is ultrasonic cleaning operating mode, when k = 0, a start command and an aggregate discharge command are issued to switch the system to normal operating mode.

[0027] Preferably, the threshold l is determined as follows: l = a × i; where i is the actual ratio of coarse aggregate to fine aggregate in the batch of crushed stone raw materials or the first real-time ratio measured in normal working mode after the system is started, and a is a correction coefficient with a value range of 1.05-1.15.

[0028] Preferably, the interval time t ranges from 5 to 10 minutes.

[0029] Preferably, the left and right aggregate reflector components further include an aggregate reflector bracket fixedly connected to the frame, a rotating shaft with both ends rotatably connected to the aggregate reflector bracket and parallel to the length direction of the screen, and a servo motor for driving the rotating shaft to rotate; the aggregate plate is connected to one side of the rotating shaft, the reflective arc surface is connected to the other side of the rotating shaft, and the reflective arc surfaces on the left and right sides and the aggregate plate can rotate tangentially around the axis of the rotating shaft.

[0030] Preferably, when the collecting plates on the left and right sides rotate to connect and form an inverted V-shaped collecting port, the upper opening width of the collecting port is 1 to 1.1 times the width of the screen.

[0031] Preferably, when the left and right reflective arc surfaces rotate to the point where they are tangentially connected and the arc surfaces face the screen, the center of the continuous arc surface formed by the left and right reflective arc surfaces is located on the center line of the screen.

[0032] Preferably, the two side walls of the screen box are arc-shaped. When the reflective arc surfaces on the left and right sides rotate to be tangent to each other and the arc surfaces face the screen mesh, the reflective arc surfaces just connect with the two side walls of the screen box, so that the center of the continuous arc surface formed by the reflective arc surfaces and the side walls of the screen box is located on the center line of the screen mesh.

[0033] Preferably, the ultrasonic transducer assembly further includes a servo motor, which is fixed to the base at the top or both sides of the screen box; the vertical ultrasonic transducer and the horizontal ultrasonic transducer are rotatably connected to the base at the top and both sides of the screen box, respectively, and the servo motor is used to drive the vertical ultrasonic transducer and the horizontal ultrasonic transducer to rotate, so as to change the incident direction of the ultrasonic waves.

[0034] Preferably, the surface of the reflective arc surface, as well as the top and sides inside the sieve box, are coated with a mirror or glaze reflective layer.

[0035] Preferably, the aggregate plate is made of a smooth steel plate.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects:

[0037] 1) This invention sets the reflective arc surface and the collecting plate together at the bottom of the screen. First, the reflective arc surface can reflect the ultrasonic waves emitted by each ultrasonic transducer and refocus them onto the screen, causing secondary vibration of the screen and improving the effect of the ultrasonic waves on the screen. Second, the drive motor can drive the reflective arc surface and the collecting plate to rotate, so that the left and right reflective arc surfaces and the collecting plate rotate in coordination. This not only does not affect the normal flow of materials, but also changes the focus point of the ultrasonic waves by driving the reflective arc surface to rotate, so that the reflected focus of the ultrasonic waves can sweep the screen at a uniform speed and in an orderly manner, thereby achieving comprehensive and uniform cleaning of the screen holes.

[0038] 2) This invention features rotatable vertical and horizontal ultrasonic transducers installed at the top and side walls of the screen box, respectively. This allows for changes in the incident angle of the ultrasonic waves, resulting in different effects. Specifically, controlling the horizontal and vertical ultrasonic transducers to emit ultrasonic waves with an incident angle at an obtuse angle to the length of the screen mesh, and applying them to the crushed stone material on the screen, utilizes the resistive force of the ultrasonic waves on damp, clumped materials to prolong their residence time on the screen surface, ensuring thorough disintegration and improving the screening effect. Conversely, controlling the horizontal and vertical ultrasonic transducers to emit ultrasonic waves with an incident angle perpendicular to the length of the screen mesh, and applying them to the screen, allows the ultrasonic waves to pass through the screen and be reflected and focused onto the screen by the arc surface formed by the reflective arc or the inner wall of the screen box, thereby cleaning clogged screen holes.

[0039] 3) This invention weighs the coarse aggregate conveyed on the coarse aggregate conveyor belt and the fine aggregate conveyor belt simultaneously by setting coarse aggregate weighing sensors and fine aggregate weighing sensors, and uses the vibrating screen analysis and control module to intelligently adjust and control the working mode of the system, so that the system can automatically switch between normal working mode, ultrasonic excitation working mode and ultrasonic cleaning working mode, and can achieve continuous, stable and efficient operation of the vibrating screen system while ensuring the screening effect. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the main view structure of this system;

[0041] Figure 2 for Figure 1 Schematic diagram of the cross-section at point AA;

[0042] Figure 3 for Figure 2 A schematic diagram of the structure when the central material collection plate rotates to the point where the two plates connect to form an inverted V-shape and the inlet of the material collection plate points towards the screen.

[0043] Figure 4 for Figure 2 Sectional view at point BB;

[0044] Figure 5 for Figure 3 Sectional view at CC;

[0045] Figure 6 This is the main view of the system;

[0046] Figure 7 This is a schematic diagram illustrating the switching of various working modes during the operation of the system of the present invention;

[0047] Figure 8This is a schematic diagram of the working principle of ultrasonic waves in the ultrasonic excitation working mode of the system of the present invention. In the diagram, a is a front view when the incident angle of the vertical ultrasonic transducer is obtuse to the length direction of the screen, and b is a top view when the incident angle of the horizontal ultrasonic transducer is obtuse to the length direction of the screen.

[0048] Figure 9 This is a schematic diagram of the working principle of the system of the present invention in the ultrasonic cleaning working mode, where a is a front view when the incident angle of the vertical ultrasonic transducer is perpendicular to the length direction of the screen, and b is a top view when the incident angle of the horizontal ultrasonic transducer is perpendicular to the length direction of the screen.

[0049] Figure 10 This is a right-side view of the structure in the system of the present invention when the arc-shooting surface and the screen box enclose a closed space.

[0050] The meanings of the labels in the above diagram are as follows: 1. Frame; 2. Screen box; 3. Screen mesh; 4. Vibrating screen motor; 5. Ultrasonic transducer assembly; 501. Vertical ultrasonic transducer; 502. Horizontal ultrasonic transducer; 6. Left aggregate reflector assembly; 601. Aggregate reflector bracket; 602. Aggregate plate; 603. Reflective arc surface; 604. Servo motor; 605. Rotating shaft; 8. Feed conveyor belt; 9. Coarse aggregate conveyor belt; 10. Fine aggregate weighing sensor; 11. Coarse aggregate weighing sensor; 12. Fine aggregate conveyor belt; 13. Right aggregate reflector assembly; 14. Agglomerated wet material. Detailed Implementation

[0051] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] The present invention will be further described in detail below with reference to the accompanying drawings.

[0054] Example 1

[0055] For information on a multi-mode stone crushing and screening system with ultrasonic-assisted vibration, please refer to [link / reference]. Figures 1 to 6The system includes a frame 1, a screen box 2 mounted on the frame 1, a vibrating screen motor 4 mounted on the screen box 2, a screen 3 mounted inside the screen box 2 for conveying and vibrating the crushed stone, a feed conveyor belt 8 connected to the feed inlet of the screen box 2, a coarse aggregate conveyor belt 9 connected to the coarse aggregate outlet of the screen 2, a fine aggregate conveyor belt 12 connected to the fine aggregate outlet of the screen 2, an ultrasonic transducer 5, a left aggregate reflector 6 and a right aggregate reflector 13 symmetrically arranged at the bottom of the screen 3 with the center line of the screen 3 as the axis, a fine aggregate weighing sensor 10, a coarse aggregate weighing sensor 11, and a vibrating screen analysis and control module.

[0056] The ultrasonic transducer assembly 5 includes multiple vertical ultrasonic transducers 501 disposed at the top of the sieve box 2 and capable of rotating along the length of the sieve mesh 3 in a plane perpendicular to the mesh surface to change the ultrasonic incident direction; and multiple horizontal ultrasonic transducers 502 disposed on both sides of the sieve box 2 and capable of rotating along the length of the sieve mesh 3 in a plane parallel to the mesh surface to change the ultrasonic incident direction. Specifically, the multiple vertical ultrasonic transducers 501 are disposed on the center line of the top of the sieve box 2, and are disposed at intervals of 0.5-1m along the length of the sieve mesh; the multiple horizontal ultrasonic transducers 502 are disposed 5-15cm above the mesh surface of the sieve mesh 3, and are disposed at intervals of 0.5-1m along the length of the sieve mesh, and are offset from the vertical ultrasonic transducers along the length of the sieve mesh.

[0057] Both the left and right material collection reflector components 6 and 13 include a material collection plate 602 arranged along the length of the screen 3 and a reflective arc surface 603 arranged along the length of the screen 3, facing away from the material collection surface of the material collection plate 602. The reflective arc surface 603 and the material collection plate 602 on the left and right sides can rotate tangentially around an axis parallel to the length of the screen 3. The two ends of the arc surface of the reflective arc surface 603 are located on their respective rotation surfaces, and the two ends of the material collection plate 602 are located within their respective rotation surfaces. This allows the material collection plates 602 on the left and right sides to rotate until they connect to form an inverted V-shaped material collection port 7, or allows the reflective arc surfaces 603 on the left and right sides to rotate until they connect tangentially and the arc surface faces the screen 3.

[0058] The coarse aggregate weighing sensor 11 and the fine aggregate weighing sensor 10 are respectively installed on the coarse aggregate conveyor belt 9 and the fine aggregate conveyor belt 12, and are used to synchronously weigh the coarse aggregate conveyed on the coarse aggregate conveyor belt 9 and the fine aggregate conveyor belt 12 at intervals t, and send the coarse aggregate weighing value and the fine aggregate weighing value to the screening performance analysis module. In order to ensure the consistency of weighing, the coarse aggregate conveyor belt 9 and the fine aggregate conveyor belt 12 can adopt a step-type conveying, that is, every interval t, the coarse aggregate conveyor belt 9 and the fine aggregate conveyor belt 12 move synchronously by one step, and at the same time, the coarse aggregate weighing sensor 11 and the fine aggregate weighing sensor 10 weigh the corresponding material at that step.

[0059] The vibrating screen analysis and control module includes:

[0060] This system is used to issue start-up commands to control the feeding of the feed conveyor belt 8, and to issue stop vibration commands to stop the horizontal ultrasonic transducer 502 and the vertical ultrasonic transducer 501 from working. At the same time, it issues collection commands to rotate the collection plates 602 on the left and right sides until they are connected to form an inverted V-shape and the feed inlet points to the collection port 7 of the screen, so that the system is in normal working mode. In normal working mode, this system is the same as a conventional vibrating screen device. It only uses the vibration generated by the vibrating screen motor 4 to drive the screen box 2 and the screen 2 to resonate at the same frequency to screen and transport the crushed stone on the screen 2. The coarse aggregate falls from the coarse aggregate outlet through the screen 2 onto the coarse aggregate conveyor belt 9, while the fine aggregate passes through the mesh of the screen 2 and falls below the screen, is guided by the collection port 7, and finally falls onto the fine aggregate conveyor belt 12.

[0061] This is used to issue an auxiliary excitation command, causing the horizontal ultrasonic transducer 502 and the vertical ultrasonic transducer 501 to emit ultrasonic waves with an incident angle at an obtuse angle to the length of the screen, which act on the crushed stone material on the screen. Simultaneously, a collection command is issued, causing the collection plates 602 on both sides to rotate until they connect to form an inverted V-shape with the inlet pointing towards the collection port 7 of the screen, thus putting the system into ultrasonic excitation mode. Preferably, the horizontal ultrasonic transducer 502 and the vertical ultrasonic transducer 501 emit ultrasonic waves with an incident angle of 120-150° to the length of the screen. In ultrasonic excitation mode, please refer to... Figure 8 The system screens crushed stone based on the following principles to reduce the risk of screen clogging or grading errors: First, it uses ultrasonic dehumidification to accelerate the evaporation of moisture in the agglomerated wet material 14, reducing the cohesive force of the agglomerated wet material 14 and causing it to disintegrate; second, it uses ultrasonic resonance to cause the agglomerated wet material 14 to vibrate and disintegrate; third, when the linear vibrating screen is working, due to the tilt of the screen, the material on the screen surface will move downward along the screen surface under the action of gravity and vibration. Some larger agglomerated wet material 14 moves faster and has a shorter residence time on the screen surface. The ultrasonic resistance force on the agglomerated wet material 14 is used to prolong its residence time on the screen surface, thereby ensuring that it can be fully disintegrated and improving the material screening effect. Since the material to be screened remains on the screen surface when the vibrating screen is working, it will hinder the passage and reflection of ultrasonic waves. Therefore, the ultrasonic excitation working mode is mainly for dehumidifying and vibrating the agglomerated wet material on the screen surface. It is a preventive cleaning and reduces grading errors, but the cleaning effect on already clogged screen holes is poor.

[0062] This is used to issue a stop command to control the feed conveyor belt 8 to stop feeding, and simultaneously issue an auxiliary cleaning command to cause the horizontal ultrasonic transducer 502 and the vertical ultrasonic transducer 501 to emit ultrasonic waves with an incident angle perpendicular to the length direction of the screen mesh, acting on the screen mesh. It also issues a reflection command to cause the left and right reflective arc surfaces 603 to rotate until they are tangentially connected and the arc surfaces face the screen mesh 3, thus putting the system into ultrasonic cleaning mode. In ultrasonic cleaning mode, please refer to... Figure 9 This method not only utilizes the principle of ultrasonic dehumidification to accelerate the evaporation of moisture in the agglomerated damp material 14 and reduce the cohesive force of the agglomerated material, but also utilizes the principle of ultrasonic resonance to cause the agglomerated damp material to vibrate and disintegrate. Furthermore, at this time, there is no large amount of material stagnating on the screen surface. The ultrasonic waves emitted by the horizontal ultrasonic transducer 502 and the vertical ultrasonic transducer 501 can pass through the screen and be reflected and focused on the screen by the arc surface formed by the reflective arc surface 603 and / or the inner wall of the screen box, thereby achieving the effect of cleaning the clogged screen holes. In addition, since the ultrasonic waves emitted by the ultrasonic transducer component can be focused on a certain area of ​​the screen after being reflected by the reflective arc surface, the vibrating screen analysis and control module can also issue a circular rotation command for the arc surface to make the reflective arc surfaces on the left and right sides rotate periodically, so that the reflection focus of the ultrasonic waves can sweep the screen at a uniform speed and in an orderly manner, thereby achieving comprehensive and uniform cleaning of the screen holes.

[0063] This is used to identify the current operating mode of the system and receive the weighing values ​​of coarse and fine aggregates under the current operating mode to calculate the real-time ratio k between the two. When the weighing values ​​of coarse and / or fine aggregates are 0, the real-time ratio k is 0. Then, the real-time ratio k is compared with a set threshold l. If the current operating mode is normal operating mode, when k > l, an auxiliary excitation command and an aggregate command are issued to switch the system to ultrasonic excitation operating mode. When k ≤ l, the current operating mode is maintained. If the current operating mode is excitation operating mode, when k > l, a stop command, an auxiliary cleaning command, and a reflection command are issued to switch the system to ultrasonic cleaning operating mode. When k ≤ l, the current operating mode is maintained. If the system is running or the current operating mode is ultrasonic cleaning operating mode, when k = 0, a start command and an aggregate discharge command are issued to switch the system to normal operating mode.

[0064] Please see Figure 7When the system of this invention is powered on or the current working mode is ultrasonic cleaning mode, since neither the coarse aggregate conveyor belt nor the fine aggregate conveyor belt carries any material, the coarse aggregate weighing sensor 11 and the fine aggregate weighing sensor 10 both acquire a coarse aggregate weighing value and a fine aggregate weighing value of 0. At this time, the real-time ratio k calculated by the vibrating screen analysis and control module is 0, and the system automatically executes the normal working mode. Therefore, after the system of this invention is powered on, it will work in the normal working mode. After running in the normal working mode for a period of time, if the screening effect of the system decreases, more fine aggregate will be mixed in with the coarse aggregate on the coarse aggregate conveyor belt. That is, the weight of the material carried on the coarse aggregate conveyor belt increases relatively, while the weight of the material carried on the fine aggregate conveyor belt decreases relatively. This causes the real-time ratio k calculated by the vibrating screen analysis and control module to increase until k > 1. Then, an auxiliary excitation command and a material collection command are issued to switch the system to the ultrasonic excitation working mode. Under normal circumstances, when switching from the normal working mode to the ultrasonic excitation working mode, under the synergistic assistance of ultrasound, the system... The screening effect on the screen surface will be improved, reducing the risk of screen clogging or gradation errors, thereby reducing the real-time ratio k to ≤ 1. At this point, the system will maintain the ultrasonic vibration mode. However, as screening continues, the screen holes may still become clogged. The ultrasonic vibration mode is less effective at cleaning clogged screens, and the real-time ratio k will continue to increase. If the real-time ratio k > 1 in the ultrasonic vibration mode, the system needs to switch to the ultrasonic cleaning mode to clean the screen holes. Since the feed conveyor belt 8 stops feeding in the ultrasonic cleaning mode, and neither the coarse nor fine aggregate conveyor belts carry material, the real-time ratio k obtained at the next interval t will inevitably be 0. The vibration screen analysis and control module will then control the system to switch to the normal working mode. Therefore, in this system, the working time of each stage of the ultrasonic cleaning mode is a fixed value t, after which it will automatically enter the normal working mode. In summary, when using the system of this invention to screen crushed stone, the typical workflow is as follows: Figure 7 As shown, the system first executes the normal working mode, then enters the ultrasonic excitation working mode, then enters the ultrasonic cleaning working mode, and then enters the normal working mode again, repeating the above process in a cycle.

[0065] Furthermore, in a preferred embodiment, the threshold l is determined as follows: l = a × i, where i is the actual ratio of coarse aggregate to fine aggregate in the batch of crushed stone raw materials, denoted as i s Alternatively, it can be the second real-time ratio measured in normal operating mode after the system boots up, denoted as i. k ;a is the correction coefficient, with a value range of 1.05-1.15; where the actual ratio i sThe measurement can be performed by the experimenter before the system is powered on, and then input into the vibrating sieve analysis and control module. The actual ratio i s This reflects the most accurate ratio of coarse and fine aggregates in this batch of crushed stone raw materials; the first real-time ratio measured in normal working mode after the system is started is 0, while the second real-time ratio is 1. k This is the ratio of the coarse aggregate weighing value to the fine aggregate weighing value collected for the second time by the coarse aggregate weighing sensor 11 and the fine aggregate weighing sensor 10 in normal working mode. At this time, the screen is not blocked, and it accurately reflects the normal screening performance of the screen. Since coarse aggregate usually contains a small amount of fine aggregate and is conveyed to the coarse aggregate conveyor belt 9, while the coarse aggregate does not pass through the screen and is conveyed to the fine aggregate conveyor belt 12, the second real-time ratio i k It will be slightly larger than the actual ratio i s In addition, the correction coefficient 'a' can be set to a reasonable value as needed. Generally, when the screening quality requirements are high, the correction coefficient 'a' can be set to a lower value, in which case the system switches between different working modes more frequently. Conversely, the correction coefficient 'a' can be set to a lower value.

[0066] Furthermore, in a preferred embodiment, the interval time t ranges from 5 to 10 minutes.

[0067] Furthermore, in a preferred embodiment, please refer to Figures 1 to 6 The left material collection reflection assembly 6 and the right material collection reflection assembly 13 also include a material collection reflection bracket 601 fixedly connected to the frame 1, a rotating shaft 605 rotatably connected to the material collection reflection bracket 601 at both ends and parallel to the length direction of the screen 3, and a servo motor 604 for driving the rotating shaft 605 to rotate; the material collection plate 602 is connected to one side of the rotating shaft 605, and the reflective arc surface 603 is connected to the other side of the rotating shaft 605. The reflective arc surfaces 603 and the material collection plate 602 on the left and right sides can rotate together around the axis of the rotating shaft 605; wherein, the servo motor 604 is electrically connected to the vibrating screen analysis and control module to receive instructions issued by the vibrating screen analysis and control module and execute corresponding actions.

[0068] Furthermore, in a preferred embodiment, when the collecting plates 602 on the left and right sides rotate to form an inverted V-shaped collecting port 7, the upper opening width of the collecting port 7 is 1 to 1.1 times the width of the screen 3, thereby preventing fine aggregate from leaking out from the upper opening of the collecting port 7.

[0069] To better focus the reflected ultrasonic waves onto the screen and improve cleaning performance, in a preferred embodiment, please refer to... Figure 10When the left and right reflective arc surfaces 603 rotate to the point where they are tangent and connected and the arc surfaces face the screen 3, the center of the continuous arc surface formed by the left and right reflective arc surfaces 603 is located on the center line of the screen.

[0070] Furthermore, in a preferred embodiment, please refer to Figure 10 The two side walls of the screen box 2 are arc-shaped. When the reflective arc surfaces 603 on the left and right sides are rotated to be tangent to each other and the arc surfaces face the screen mesh 3, the reflective arc surfaces 603 are just connected with the two side walls of the screen box 2, so that the center of the continuous arc surface formed by the reflective arc surfaces 603 and the side walls of the screen box 2 is located on the center line of the screen mesh. Based on the above structure, the reflective arc surfaces 603 can form a relatively closed space with the screen box, and at the same time, the ultrasonic waves can be better focused on the screen mesh after reflection, thereby improving the cleaning effect of the screen mesh.

[0071] Furthermore, in a preferred embodiment, the ultrasonic transducer assembly 5 further includes a servo motor fixed to the base at the top or sides of the screen box 2; the vertical ultrasonic transducer 501 and the horizontal ultrasonic transducer 502 are rotatably connected to the base at the top and sides of the screen box 2, respectively; the servo motor is used to drive the vertical ultrasonic transducer 501 and the horizontal ultrasonic transducer 502 to rotate, so as to change the incident direction of the ultrasonic waves; the above-mentioned structure for rotating the vertical ultrasonic transducer 501 and the horizontal ultrasonic transducer 502 is prior art, which is similar to the rotation mechanism used by a camera to acquire video images from different directions or angles, therefore, no corresponding structural diagram is given in this embodiment.

[0072] Furthermore, in a preferred embodiment, the surface of the reflective arc surface 603, as well as the top and sides of the screen box 2, are coated with a mirror or glaze reflective layer to improve the reflection effect of ultrasonic waves.

[0073] Furthermore, in a preferred embodiment, the aggregate plate 602 is made of a smooth-surfaced steel plate.

Claims

1. A multi-mode crushing and screening system for ultrasonic-assisted vibration, comprising a frame (1), a screen box (2) mounted on the frame (1), a vibrating motor (4) mounted on the screen box (2), a screen (3) mounted inside the screen box (2) for conveying and screening crushed stone, a feed conveyor belt (8) corresponding to the feed inlet of the screen box (2), a coarse aggregate conveyor belt (9) corresponding to the coarse aggregate outlet of the screen (3), and a fine aggregate conveyor belt (12) corresponding to the fine aggregate outlet of the screen (3), characterized in that, Also includes: Ultrasonic transducer (5), left aggregate reflector (6) and right aggregate reflector (13) symmetrically arranged at the bottom of screen (3) with the center line of screen (3) as the axis, fine aggregate weighing sensor (10), coarse aggregate weighing sensor (11), vibrating screen analysis and control module; The ultrasonic transducer assembly (5) includes a plurality of vertical ultrasonic transducers (501) disposed at the top of the sieve box (2) and capable of rotating along the length of the sieve in a plane perpendicular to the sieve mesh (3) to change the ultrasonic incident direction, and a plurality of horizontal ultrasonic transducers (502) disposed on both sides of the sieve box (2) and capable of rotating along the length of the sieve in a plane parallel to the sieve mesh (3) to change the ultrasonic incident direction. The left and right aggregate reflective components (6 and 13) each include an aggregate plate (602) arranged along the length of the screen (3) and a reflective arc surface (603) arranged along the length of the screen (3) away from the aggregate surface of the aggregate plate (602). The reflective arc surface (603) and the aggregate plate (602) on the left and right sides can rotate tangentially around an axis parallel to the length of the screen (3). The two ends of the arc surface of the reflective arc surface (603) are located on their respective rotation surfaces, and the two ends of the aggregate plate (602) are located within their respective rotation surfaces. The coarse aggregate weighing sensor (11) and fine aggregate weighing sensor (10) are respectively installed on the coarse aggregate conveyor belt (9) and the fine aggregate conveyor belt (12) to weigh the coarse aggregate conveyed on the coarse aggregate conveyor belt (9) and the fine aggregate conveyor belt (12) at intervals t, and send the coarse aggregate weighing value and the fine aggregate weighing value to the screening performance analysis module. The vibrating screen analysis and control module includes: Used to issue a start command to control the feeding of the feed conveyor belt (8), and to issue a stop excitation command to stop the horizontal ultrasonic transducer (502) and the vertical ultrasonic transducer (501) from working. At the same time, it issues a collection command to rotate the collection plates (602) on the left and right sides to the collection port (7) where the two are connected to form an inverted V-shape and the feed inlet points to the screen, so that the system is in normal working mode. The auxiliary excitation command is used to make the horizontal ultrasonic transducer (502) and the vertical ultrasonic transducer (501) emit ultrasonic waves with an incident angle of obtuse angle to the length direction of the screen, which act on the crushed stone material on the screen. At the same time, the collection command is issued to make the collection plates (602) on the left and right sides rotate until the two are connected to form an inverted V-shape and the inlet points to the collection port (7) of the screen, so that the system is in the ultrasonic excitation working mode. The system is used to issue a stop command to control the feed conveyor belt (8) to stop feeding, and at the same time issue an auxiliary cleaning command to make the horizontal ultrasonic transducer (502) and the vertical ultrasonic transducer (501) emit ultrasonic waves with an incident angle perpendicular to the length direction of the screen and act on the screen. It also issues a reflection command to make the reflection arc surfaces (603) on the left and right sides rotate to a position where the two are tangent and connected and the arc surfaces face the screen (3), so that the system is in ultrasonic cleaning working mode. This is used to identify the current operating mode of the system and receive the weighing values ​​of coarse and fine aggregates under the current operating mode to calculate the real-time ratio k between the two. When the weighing values ​​of coarse and / or fine aggregates are 0, the real-time ratio k is 0. Then, the real-time ratio k is compared with a set threshold l. If the current operating mode is normal operating mode, when k > l, an auxiliary excitation command and an aggregate command are issued to switch the system to the excitation operating mode. When k ≤ l, the current operating mode is maintained. If the current operating mode is ultrasonic excitation operating mode, when k > l, a stop command, an auxiliary cleaning command, and a reflection command are issued to switch the system to the ultrasonic cleaning operating mode. When k ≤ l, the current operating mode is maintained. If the system is running or the current operating mode is ultrasonic cleaning operating mode, when k = 0, a start command and an aggregate discharge command are issued to switch the system to normal operating mode.

2. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, The threshold l is determined as follows: l = a × i; where i is the actual ratio of coarse aggregate to fine aggregate in the batch of crushed stone raw materials or the second real-time ratio measured in normal working mode after the system is turned on, and a is a correction coefficient with a value range of 1.05-1.

15.

3. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, The interval time t ranges from 5 to 10 minutes.

4. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, The left material collection reflector (6) and the right material collection reflector (13) also include a material collection reflector bracket (601) fixedly connected to the frame (1), a rotating shaft (605) with both ends rotatably connected to the material collection reflector bracket (601) and parallel to the length direction of the screen (3), and a servo motor (604) for driving the rotating shaft (605) to rotate; the material collection plate (602) is connected to one side of the rotating shaft (605), and the reflective arc surface (603) is connected to the other side of the rotating shaft (605). The reflective arc surface (603) on the left and right sides and the material collection plate (602) can rotate tangentially around the axis of the rotating shaft (605).

5. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, When the collecting plates (602) on the left and right sides rotate to form an inverted V-shaped collecting port (7), the upper opening width of the collecting port (7) is 1 to 1.1 times the width of the screen (3).

6. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, When the left and right reflective arc surfaces (603) rotate to the point where they are tangentially connected and the arc surfaces face the screen (3), the center of the continuous arc surface formed by the left and right reflective arc surfaces (603) is located on the center line of the screen.

7. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 6, characterized in that, The two side walls of the sieve box (2) are arc-shaped. When the reflective arc surfaces (603) on the left and right sides rotate to be tangent to each other and the arc surfaces face the screen (3), the reflective arc surfaces (603) are just connected to the two side walls of the sieve box (2), so that the center of the continuous arc surface formed by the reflective arc surfaces (603) and the side walls of the sieve box (2) is located on the center line of the screen.

8. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, The ultrasonic transducer assembly (5) also includes a servo motor, which is fixed to the top of the sieve box (2) or the base on both sides of the sieve box (2); the vertical ultrasonic transducer (501) and the horizontal ultrasonic transducer (502) are respectively rotatably connected to the top and the bottom of both sides of the sieve box (2), and the servo motor is used to drive the vertical ultrasonic transducer (501) and the horizontal ultrasonic transducer (502) to rotate so as to change the incident direction of the ultrasonic waves.

9. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, The surface of the reflective arc surface (603) and the top and sides of the sieve box (2) are coated with a mirror or glaze reflective layer.

10. The multi-mode stone crushing and screening system with ultrasonic-assisted vibration as described in claim 1, characterized in that, The aggregate plate (602) is made of a smooth steel plate.

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