Grain shape optimization grading control device for tuff machine-made sand

Abstract

The invention discloses a grain shape optimization grading control device for tuff machine-made sand, and relates to the technical field of building material processing. The device comprises a feeding unit, a grain shape optimization unit, a real-time monitoring unit, a grading control unit and an intelligent control system. The core of the invention lies in that the intelligent control system carries out calculation through a built-in comprehensive quality evaluation model containing sphericity, fineness modulus and stone powder content based on real-time grain shape, grading data and stone powder content fed back by a real-time monitoring unit; and the rotating speed of the grain shape optimization unit and the vibration frequency and the airflow speed of the grading control unit are dynamically adjusted by using a feedback control algorithm, so that integrated and intelligent closed-loop control of grain shape optimization and grading control is realized. The method is particularly suitable for solving the technical problem that in tuff machine-made sand production, the content of needle-sheet-shaped particles and stone powder is difficult to stably control, and the stability of product quality and production benefits can be effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of building material processing technology, specifically relating to a particle shape optimization and gradation control device for manufactured tuff sand. Background Technology

[0002] Tuff, as a type of volcanic clastic rock, has the characteristics of low density, high porosity, and brittle texture. During the production of manufactured sand, brittle fracture can easily lead to problems such as excessive needle-like and flaky particles and large fluctuations in gradation, which directly affect the performance of manufactured sand in building materials such as mortar and concrete.

[0003] Manufactured tuff sand, as a substitute for natural sand, has advantages such as abundant resources and environmental friendliness. However, its production faces two major bottlenecks: particle shape and gradation issues. Tuff has a loose structure, and after crushing, it easily produces a large number of needle-like and flaky particles with a length-to-thickness ratio greater than 3:1, reducing the strength and workability of concrete. Traditional shaping equipment, such as vertical shaft impact crushers, relies solely on experience to adjust the rotation speed, lacking quantitative control. This results in manufactured sand with a needle-like and flaky content often exceeding 15%, far exceeding the national standard requirement of less than 10%, leading to low efficiency in particle shape optimization. Furthermore, the gradation of manufactured sand is prone to the phenomenon of "large at both ends and small in the middle," affecting the density of concrete. Existing vibrating screens use fixed screens, which cannot dynamically respond to raw material fluctuations, resulting in a gradation pass rate of less than 60%.

[0004] While existing technologies attempt to integrate crushing and screening, they suffer from the following drawbacks: no correlation model between particle shape and gradation has been established, and the shaping and screening processes operate independently, resulting in low overall efficiency; control relies on manual experience and lacks mathematical model support, making it impossible to optimize parameters in real time; and there is a lack of targeted design for the brittle characteristics of tuff, such as low hardness and well-developed bedding, leading to high equipment wear rates.

[0005] Therefore, there is an urgent need for a device with a simple structure and intelligent control to achieve synergistic optimization of particle shape and gradation of manufactured tuff sand. Summary of the Invention

[0006] This invention addresses the problems of existing technologies by providing a particle shape optimization and gradation control device for manufactured tuff sand. Through mechanical structural innovation and mathematical model-driven design, it solves the problems of poor particle shape and unreasonable gradation, ensuring that the content of needle-like and flaky particles in the manufactured sand is less than 8%, and that the fineness modulus meets the Class I sand standard.

[0007] To solve the above technical problems, the present invention provides the following technical solution: a particle shape optimization and gradation control device for manufactured tuff sand, comprising a feeding unit for conveying semi-finished manufactured tuff sand produced by a sand making machine into the particle shape optimization and gradation control device; characterized in that it further comprises: a particle shape optimization unit, a real-time monitoring unit, a gradation control unit, and an intelligent control system; the intelligent control system is electrically connected to the particle shape optimization unit, the real-time monitoring unit, and the gradation control unit respectively;

[0008] The particle shape optimization unit is connected to the feeding unit and adopts a dual-cavity shaping chamber. It dynamically adjusts the shaping parameters of the tuff manufactured sand through a mathematical model to reduce needle-shaped and flaky particles.

[0009] The real-time monitoring unit is connected to the particle shape optimization unit to acquire the particle shape parameters and gradation curve of the material in real time. The gradation control unit is connected to the real-time monitoring unit to classify the material according to its coarseness for subsequent processing.

[0010] The intelligent control system is equipped with a process control model for the quality of manufactured tuff sand. Based on the particle shape parameters and gradation curves of the material output by the real-time monitoring unit, the intelligent control system dynamically adjusts the relevant control parameters of the particle shape optimization unit and the gradation control unit by calculating the quality index and preset target value in real time through the process control model, and iteratively optimizes the particle shape of the manufactured tuff sand.

[0011] Furthermore, the aforementioned particle shape optimization unit includes a primary shaping chamber and a secondary optimization chamber connected thereto. The primary shaping chamber crushes and shapes the tuff manufactured sand through high-energy impact, while the secondary optimization chamber optimizes the particle shape through material layer grinding, that is, by utilizing the mutual friction between the sand materials.

[0012] Furthermore, the aforementioned real-time monitoring unit includes an image acquisition unit, a laser particle size analysis unit, and a first conveying system. The image acquisition unit is located at the feed inlet of the gradation control unit. The real-time monitoring unit receives the shaped material conveyed from the particle shape optimization unit by the first conveying system and captures particle images in real time using a high-speed industrial camera. The laser particle size analysis unit monitors the particle size distribution through a laser particle size analyzer.

[0013] Furthermore, the aforementioned gradation control unit includes: a variable frequency vibrating screen and an air classifier, as well as a return chute. The variable frequency vibrating screen includes several layers of screen mesh, and the mesh size decreases sequentially from the upper layer to the lower layer. The air classifier includes a fan and an adjustable damper. The return chute is used to re-transport coarse particles to the particle shape optimization unit for iterative optimization.

[0014] Furthermore, the process control model for the quality of manufactured tuff sand products in the aforementioned intelligent control system calculates the comprehensive quality index of the material based on the sphericity, fineness modulus, and stone powder content, as shown in the following formula:

[0015] ,

[0016] In the formula, Q is the overall quality index; Sphericity; The fineness modulus; For real-time monitoring of stone powder content; The optimal stone powder content is determined for concrete based on different usage requirements; , , These are the weighting coefficients, and .

[0017] Furthermore, the aforementioned intelligent control system includes a central controller that optimizes particle shape by adjusting the rotor speed n of the particle shape optimization unit; adjusts the fineness modulus by adjusting the vibration frequency f of the square hole screens of each aperture in the frequency-controlled vibrating screen of the gradation control unit; and controls the stone powder content by adjusting the airflow velocity v of the airflow separator of the gradation control unit.

[0018] Furthermore, the aforementioned particle shape optimization gradation control device for manufactured tuff sand also includes a stone powder collection bin, a finished manufactured sand bin, and a second conveying system, all connected to the gradation control unit.

[0019] The stone powder collection bin receives ultrafine particles conveyed by the gradation control unit; the finished manufactured sand bin receives qualified particles conveyed by the gradation control unit through the second conveying system;

[0020] Furthermore, the aforementioned image acquisition unit uses a high-speed industrial camera with an image resolution of no less than 2048×2048 pixels to identify particles with a diameter of 0.08mm–4.75mm, and the measurement error range of the laser particle size analysis unit is ±0.5%.

[0021] Furthermore, the aforementioned fineness modulus is calculated as follows:

[0022] ,

[0023] In the formula, A1, A2, A3, A4, A5, and A6 are the cumulative sieve residue percentages for square-hole sieves with apertures of 4.75 mm, 2.36 mm, 1.18 mm, 0.60 mm, 0.30 mm, and 0.15 mm, respectively.

[0024] Furthermore, the screen apertures of the aforementioned variable frequency vibrating screen (41) from top to bottom are 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, and 0.15mm, respectively.

[0025] Compared with the prior art, the beneficial technical effects of the present invention using the above technical solution are as follows:

[0026] By integrating particle shape optimization and gradation control into a single system and achieving closed-loop intelligent regulation of the production process through online monitoring and feedback control based on mathematical models, the system can dynamically adapt to fluctuations in the characteristics of tuff raw materials, adjust operating parameters in real time, and ensure that the particle shape and gradation of the final product remain stable within the optimal range. By precisely controlling the stone powder content and the amount of recycled material, the system reduces waste of raw materials and excessive energy consumption, thereby improving production efficiency and economy. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 This is a flowchart illustrating the operation of this invention.

[0029] In the diagram, 1-feeding unit; 2-particle shape optimization unit; 3-real-time monitoring unit; 4-gradation control unit; 5-intelligent control system; 6-stone powder collection bin; 7-finished manufactured sand bin; 8-first conveying system; 9-second conveying system; 21-first-stage shaping chamber; 22-second-stage optimization chamber; 41-variable frequency vibrating screen; 42-air classifier; 43-return chute; 51-central controller. Detailed Implementation

[0030] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0031] In this invention, various aspects of the invention are described with reference to the accompanying drawings, in which numerous illustrative embodiments are shown. Embodiments of the invention are not limited to those depicted in the drawings. It should be understood that the invention is implemented through any of the various concepts and embodiments described above, as well as the concepts and embodiments described in detail below, because the concepts and embodiments disclosed herein are not limited to any particular implementation. Furthermore, some aspects of the invention disclosed may be used alone or in any suitable combination with other aspects of the invention disclosed.

[0032] refer to Figures 1 to 2 An embodiment provides a particle shape optimization and gradation control device for manufactured tuff sand, comprising: a feeding unit 1 for conveying semi-finished manufactured tuff sand produced by a sand making machine into the particle shape optimization and gradation control device; and further comprising: a particle shape optimization unit 2, a real-time monitoring unit 3, a gradation control unit 4, and an intelligent control system 5; the intelligent control system 5 is electrically connected to the particle shape optimization unit 2, the real-time monitoring unit 3, and the gradation control unit 4 respectively.

[0033] The particle shape optimization unit 2 is connected to the feeding unit 1 and adopts a dual-cavity shaping chamber. It dynamically adjusts the shaping parameters of the tuff manufactured sand through a mathematical model to reduce needle-like and flaky particles. The dual-cavity shaping chamber is divided into a primary shaping chamber 21 and a secondary optimization chamber 22. It is equipped with a centrifugal rotor and an adjustable angle impact plate. The primary shaping chamber 21 mainly crushes and shapes the tuff manufactured sand through high-energy impact, while the secondary optimization chamber 22 mainly optimizes the particle shape through material layer grinding, that is, by utilizing the mutual friction between the sand materials.

[0034] The primary shaping chamber 21 of the particle shape optimization unit 2 is located on the upper side of the rotor, and its inner wall is inlaid with a first impact plate made of high manganese steel. The installation angle of this impact plate is close to 80°, which is intended to allow the high-speed material flow ejected from the rotor to collide with it at a near-vertical angle. According to the momentum theorem, this high-angle impact can generate huge impact force, instantly crushing larger tuff particles. The purpose is to efficiently crush incoming materials smaller than 45mm to smaller than 10mm and initially remove sharp edges. The secondary optimization chamber 22 is located below the rotor and has a vortex structure. The upper part of its inner wall is equipped with a second impact plate made of composite ceramic to improve wear resistance. Its installation angle is close to 50°. This smaller angle allows the material to collide with it at a shallower incident angle, generating more shear force to "grind" and "trim" the particles. The lower part of the chamber is lined with a peripheral plate made of high-chromium cast iron, which, together with the dense "stone curtain" ejected by the rotor, constitutes the material layer grinding zone. Within the secondary optimization chamber 22, the primary process shifts from simple impact crushing to a shaping stage dominated by inter-layer grinding. A large number of particles extend their movement path within the vortex chamber, allowing for sufficient and continuous friction and grinding between particles and between particles and the liner. This process effectively rounds the edges of the particles, significantly improving their sphericity. Meanwhile, by avoiding high-energy impacts, the generation of secondary stone powder is greatly suppressed, achieving a balance between "efficient shaping" and "low-over-grinding".

[0035] The real-time monitoring unit 3 is connected to the particle shape optimization unit 2 and is used to acquire the particle shape parameters and gradation curves of the material in real time. The gradation control unit 4 is connected to the real-time monitoring unit 3 and is used to classify the material according to its fineness for subsequent processing. In this embodiment, the real-time monitoring unit consists of an image acquisition unit and a laser particle size analysis unit. The image acquisition unit includes a high-speed industrial camera, which is placed at the feed inlet of the gradation control unit 4 to capture particle images in real time. The laser particle size analysis unit mainly uses a laser particle size analyzer to monitor the particle size distribution.

[0036] Tuff raw material is processed into semi-finished tuff manufactured sand by a sand making machine. This semi-finished sand is then conveyed into the system via feeding unit 1, where it first enters particle shape optimization unit 2 for particle shape shaping. The shaped material then passes through the first conveying system 8, above the real-time monitoring unit 3. The high-speed industrial camera in the real-time monitoring unit 3 acquires particle images and calculates the average sphericity; simultaneously, a laser particle size analyzer rapidly scans the material to obtain real-time particle size distribution data.

[0037] The intelligent control system 5 incorporates a process control model for the quality of manufactured tuff sand. Based on the particle shape parameters and gradation curves of the material output by the real-time monitoring unit 3, the intelligent control system 5 dynamically adjusts the relevant control parameters of the particle shape optimization unit 2 and the gradation control unit 4 through real-time calculation of the quality index and preset target value using the process control model, iteratively optimizing the particle shape of the manufactured tuff sand. The particle shape parameters and gradation curve data are transmitted to the central controller 51 in real time. The central controller 51 calculates the current comprehensive quality index Q based on the pre-stored optimization objective function and compares it with the target value. The comparison is performed. The controller bases the comparison on the deviation. The rotor speed of particle shape optimization unit 2 is generated using a fuzzy PID algorithm. The vibration frequency of the variable frequency vibrating screen 41 of the gradation control unit 4 The airflow velocity v of the airflow classifier 42 is adjusted.

[0038] The gradation control unit 4 includes a variable frequency vibrating screen 41, an air classifier 42, and a return chute 43. The screen mesh sizes of the variable frequency vibrating screen 41 are 4.75 mm, 2.36 mm, 1.18 mm, 0.60 mm, 0.30 mm, and 0.15 mm, respectively. The air classifier 42 includes a fan and an adjustable damper, with a wind speed range of 5–12 m / s.

[0039] The material then enters the gradation control unit 4. The variable frequency vibrating screen 41 and the air classifier 42 separate the material according to the received instructions. The coarse particles are returned to the particle shape optimization unit 2 through the return chute 43 for further shaping. The qualified particles are used as finished products and enter the finished product manufactured sand silo 7 through the second conveying system 9. The stone powder is collected from the stone powder collection silo 6 and can be used as a by-product.

[0040] The intelligent control system of the entire system is a continuous closed loop, such as... Figure 2 As shown, its operation steps are as follows:

[0041] First, data collection is performed. The shaped material flows through the real-time monitoring unit 3. A high-speed industrial camera captures images of the falling particles at 30 frames per second, and the average sphericity of the material is calculated in real time using an image processing algorithm. In this embodiment, the goal is to determine the sphericity. The particle size distribution remains stable above 0.8. Simultaneously, an online laser particle size analyzer scans the material in real time, generating a complete particle size distribution curve within seconds, which can be used as a reference for the gradation curve. In this embodiment, the target fineness modulus requirement is... The target stone powder content is between 2.3 and 3.2. Set to 8%.

[0042] Secondly, there is quality assessment and decision-making. The central controller 51 embedded in the intelligent control system receives... , and After the data is collected, it is substituted into the pre-stored comprehensive quality index (Q) model for calculation: (The weighting coefficient here is taken as...) , , (emphasizing the primacy of particle shape optimization). The central controller 51 compares the real-time calculated Q value with the set target value. Compare and calculate the deviation. Simultaneously, the sphericity deviation is calculated. Fineness modulus deviation and deviation in stone powder content .

[0043] Then comes intelligent feedback and execution. The fuzzy PID control algorithm embedded in the central controller 51 is activated, according to... and The magnitude and trend of change are used to output adjustment instructions:

[0044] When sphericity If the speed is too low, increase the rotation speed of the particle shape optimization unit. Increase impact energy and grinding energy to improve the particle shape of manufactured sand; when the fineness modulus When the particle size is less than the minimum limit of 2.3 for Class I sand, increasing the vibration frequency f of the square-hole screen with a larger aperture in the frequency conversion vibrating screen accelerates the collection of coarser particles and increases the fineness modulus; when the fineness modulus... When the vibration frequency exceeds the maximum limit of 3.2 for Class I sand, increase the vibration frequency of the square-hole sieve with smaller aperture and decrease the vibration frequency of the sieve with larger aperture to reduce the collection of coarse particles and lower the fineness modulus; when When the stone powder content exceeds the preset optimal value, the airflow velocity v of the air classifier is increased to separate and remove more stone powder particles; the proportion of coarse particles returned to the particle shape optimization unit is also finely adjusted according to the gradation situation to ensure the continuity of the overall gradation.

[0045] Finally, there's the cycle and stabilization. The adjusted material is monitored, evaluated, and regulated again… this cycle repeats continuously, forming a dynamic, adaptive, intelligent closed-loop control system. This system can automatically compensate for disturbances caused by fluctuations in the tuff raw material, ensuring that the manufactured sand collected from the finished product sand silo maintains a consistently stable particle shape, gradation, and stone powder content within the preset optimal range.

[0046] In summary, this invention, through mechanical innovation of a dual-cavity shaping chamber and intelligent quality evaluation and feedback control based on mathematical models, successfully and systematically solves the problem of difficulty in balancing particle shape and gradation in the production of manufactured sand from tuff, providing an efficient, stable, and high-quality production solution.

[0047] While the present invention has been described above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A device for controlling the grain shape and grading of tuff tamped sand, comprising a feed unit (1) for feeding tuff tamped sand semi-finished products produced by a sand making machine into the device for controlling the grain shape and grading; characterized in that, Also includes: Particle shape optimization unit (2), real-time monitoring unit (3), gradation control unit (4), and intelligent control system (5); the intelligent control system (5) is respectively connected with particle shape optimization unit (2), real-time monitoring unit (3) and gradation control unit (4) electric connection; Particle shape optimization unit (2) is connected to feeding unit (1), adopts double cavity shaping cavity, adjusts the shaping parameter of tuff mechanism sand through mathematical model dynamically, reduces the needle flaky particle; Real-time monitoring unit (3) is connected to particle shape optimization unit (2), is used for real-time acquisition of the particle shape parameter and gradation curve of material, gradation control unit (4) is connected to real-time monitoring unit (3), is used for classifying material according to the degree of thickness, subsequent processing is carried out; Intelligent control system (5) is provided with the process control model of tuff mechanism sand product quality, the intelligent control system (5) is based on the particle shape parameter and gradation curve of material exported by real-time monitoring unit (3), the quality index calculated by process control model in real time and preset target value, dynamically adjusts the relevant control parameters of particle shape optimization unit (2) and gradation control unit (4), iteratively optimizes the particle shape of tuff mechanism sand.

2. A tuff machine-made sand grain shape optimization grading control device according to claim 1, characterized in that, Particle shape optimization unit (2) includes primary shaping cavity (21) and the secondary optimization cavity (22) connected therewith, the primary shaping cavity (21) is broken and shaped to tuff mechanism sand by high-energy impact, the secondary optimization cavity (22) is optimized particle shape by material layer grinding, that is, by mutual friction between sand materials.

3. The apparatus for controlling the grain shape optimized gradation of tuff machine-made sand according to claim 1, characterized in that, Real-time monitoring unit (3) includes image acquisition unit, laser particle size analysis unit and first conveying system (8), image acquisition unit is placed in the feeding port of gradation control unit (4), real-time monitoring unit (3) receives the shaped material conveyed from particle shape optimization unit (2) by first conveying system (8), uses high-speed industrial camera to shoot particle image in real time;Laser particle size analysis unit monitors particle size distribution by laser particle size analyzer.

4. The apparatus for controlling the grain shape optimization gradation of tuff machine-made sand according to claim 1, characterized in that, The gradation control unit (4) includes: variable frequency vibrating screen (41) and air flow classifier (42), and return chute (43), the variable frequency vibrating screen (41) includes several layers of screen mesh, and the screen mesh is sequentially reduced from the upper layer to the lower layer aperture;Airflow classifier (42) includes a fan and an adjustable air door, and the return chute (43) is used to convey the coarse particle material back to the particle shape optimization unit (2) for iterative optimization.

5. The apparatus for controlling the grain shape optimization gradation of tuff machine-made sand according to claim 1, characterized in that, The process control model of tuff mechanism sand product quality in intelligent control system (5) calculates the comprehensive quality index of material according to the sphericity, fineness modulus and stone powder content of material, as follows: ， In the formula, Q is a comprehensive quality index; is a sphericity; is a fineness modulus; is a real-time monitored stone powder content; is an optimal stone powder content determined according to different use requirements of the concrete; , , is a weight coefficient, and .

6. The apparatus for controlling the grain shape optimization gradation of tuff machine-made sand according to claim 1, characterized in that, Intelligent control system (5) includes central controller (51), which optimizes particle shape by adjusting rotor speed n of particle shape optimization unit (2);Adjust the vibration frequency f of each aperture square hole screen of variable frequency vibrating screen (41) of gradation control unit (4) to adjust the fineness modulus;Adjust the airflow velocity v of air flow classifier (42) of gradation control unit (4) to control the stone powder content.

7. The apparatus for controlling the grain shape optimized gradation of tuff machine-made sand according to claim 1, characterized in that, Also includes stone powder collection bin (6) and finished mechanism sand bin (7) connected with gradation control unit (4) respectively, second conveying system (9); The stone powder collecting bin (6) receives the ultra-fine particles delivered by the grading control unit (4); the finished machine-made sand bin (7) receives the qualified particles delivered by the grading control unit (4) through the second conveying system (9).

8. The apparatus for controlling the grain shape optimized gradation of tuff machine-made sand according to claim 3, characterized in that, The image resolution of the high-speed industrial camera used by the image acquisition unit is not less than 2048*2048 pixels, which is used to identify particles with a particle size of 0.08mm-4.75mm, and the measurement error range of the laser particle size analysis unit is ±0.5%.

9. The apparatus for controlling the particle shape optimized gradation of tuff machine-made sand according to claim 5, characterized in that, The fineness modulus is calculated as follows: ， In the formula, A1, A2, A3, A4, A5, A6 are the cumulative percentage of the square hole screen, respectively: 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, 0.15mm.

10. A tuff machine-made sand grain shape optimization grading control device according to claim 6, characterized in that, The screen mesh aperture of the frequency conversion vibrating screen (41) arranged from top to bottom is: 4.75mm, 2.36mm, 1.18mm, 0.60mm, 0.30mm, 0.15mm.

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