Gravel aggregate mixing and stirring device

Abstract

The invention discloses a gravel aggregate mixing and stirring device. The gravel aggregate mixing and stirring device comprises a horizontal stirring barrel, a stirring regulation and control system, a feeding system and a quality detection and feedback system. Wherein a plurality of layers of stirring blade groups are arranged in the horizontal stirring barrel, a cooling spraying assembly is installed, the stirring regulation and control system controls the rotating speed of a driving motor and starting and stopping of the spraying assembly through a central controller in combination with data of a temperature sensor and a pressure sensor, and the feeding system controls feeding of each storage bin through an electric feeding valve according to a preset proportion. The quality detection and feedback system analyzes and judges the mixing uniformity degree through a discharge port image and feeds back the mixing uniformity degree to the central controller so as to adjust the opening degree of the feeding valve and the rotating speed of the motor, and closed-loop control is formed. The device is mainly used for efficiently mixing and stirring gravel aggregate in constructional engineering, and the aggregate mixing uniformity and the intelligent regulation and control level in the stirring process can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering machinery and equipment, and more specifically, to a sand and gravel aggregate mixing and stirring device. Background Art

[0002] In the field of construction engineering, the mixing of sand and gravel aggregates is a key link in the process of concrete preparation, and its mixing quality directly affects the mechanical properties and durability of the building structure. The existing sand and gravel aggregate mixing devices face the following technical problems in practical applications: First, it is difficult to control the mixing uniformity. Traditional mixing equipment mostly uses a fixed-speed mixing blade structure, which lacks a dynamic adjustment mechanism for material properties (such as particle grading and moisture content). For example, when sand and gravel aggregates of different particle sizes are mixed, coarse aggregates and fine aggregates are prone to stratification due to gravity differences, and the fixed mixing mode is difficult to effectively break this physical separation, resulting in uneven distribution of local aggregates during discharging. In addition, the increase in material temperature during the mixing process may cause cement to hydrate prematurely, further affecting the mixing uniformity, but existing devices often do not have real-time temperature monitoring and cooling control components, and cannot intervene in material performance changes caused by abnormal temperature in a timely manner.

[0003] Secondly, the feed ratio accuracy is insufficient. Traditional feeding systems usually rely on manual setting of the feed valve opening, lacking real-time monitoring and closed-loop control of material flow. When the material inventory in the storage bin changes or the material humidity fluctuates, the feeding resistance may change, resulting in a deviation between the actual feed flow and the preset ratio. For example, when the moisture content of fine aggregate is high, it is easy to form lumps, block the feed pipe or cause poor feeding, and the existing device is not equipped with flow sensors and anti-blocking components, making it difficult to dynamically adjust the feeding parameters to maintain the ratio accuracy. In addition, when multi-component aggregates are fed at the same time, the differences in the falling speed and flow characteristics of different materials may cause confusion in the feeding sequence, further exacerbating the ratio error.

[0004] Furthermore, the level of intelligent control of the mixing process is limited. The mixing parameters of existing devices (such as motor speed, spray start and stop) are mostly preset fixed values, and cannot be dynamically adjusted according to the real-time working conditions in the mixing chamber (such as material pressure, mixing uniformity). For example, when the material accumulation in the mixing chamber causes the pressure to increase, if the speed is not reduced in time, it may cause equipment overload, but the traditional control system lacks pressure monitoring and speed linkage mechanism; for example, when uneven mixing is found during discharging, manual shutdown and parameter adjustment are required, and real-time feedback and automatic correction cannot be achieved, resulting in low production efficiency and insufficient quality stability.

[0005] In addition, there is a lag in the quality inspection process. Traditional quality inspections mostly rely on manual sampling and analysis, and are unable to monitor the discharging process in real time, resulting in unqualified materials not being intercepted and reworked in a timely manner. For example, the particle dispersion and moisture content distribution after the mixing of sand and gravel aggregates are key indicators affecting the workability of concrete. However, existing devices lack online detection means and it is difficult to quickly identify mixing defects and adjust process parameters during the mixing process, resulting in quality control relying on post-inspection, increasing production losses and quality risks.

[0006] The problem lies in that the existing mixing devices fail to establish a closed-loop system of "detection - control - feedback", and there is a lack of data linkage and intelligent collaboration between various functional modules (such as feeding, mixing, and detection). For example, operating condition data such as temperature and pressure are not dynamically associated with mixing parameters, flow detection is not in a closed-loop control with the feeding valve, and the quality inspection results are not fed back to the feeding and mixing links to achieve process correction. At the same time, the adaptability of the equipment structure design to material characteristics is insufficient. For example, the form of the mixing paddle is single, the anti-blocking ability of the feeding pipe is weak, and the detection module is easily interfered by dust, further restricting the improvement of mixing quality and production efficiency.

[0007] In the process of solving these problems, the technical difficulties faced include how to establish a dynamic ratio adjustment strategy to achieve smooth switching of feeding parameters without interrupting the production process. These technical problems make it difficult for existing devices to meet the higher requirements of modern construction projects for the mixing quality of sand and gravel aggregates and intelligent production. Summary of the Invention

[0008] An object of the present invention is to provide a sand and gravel aggregate mixing and stirring device. Existing sand and gravel aggregate mixing and stirring devices have problems such as insufficient mixing uniformity, inability to adjust stirring parameters in real time and dynamically, low feeding ratio accuracy, and lack of closed-loop feedback. For example, stirring at a fixed speed easily causes material stratification, and the lack of temperature and pressure monitoring may cause equipment overload or deterioration of material properties. Manual parameter adjustment has a lag response and is difficult to adapt to multi-condition requirements. It is necessary to achieve coordinated optimization of stirring, detection, and control through integrated design to improve mixing quality and production efficiency.

[0009] Traditional feeding systems face problems such as large fluctuations in material flow, easy blockage, and lag in ratio switching. For example, high-humidity fine aggregates are prone to caking and blocking the feeding pipe, the lack of flow detection leads to large ratio errors, and manual adjustment is difficult to cope with real-time changes. It is necessary to solve the problems of insufficient feeding accuracy and poor adaptability through real-time flow monitoring, anti-blocking structure design, and dynamic ratio switching mechanism to ensure the stable transportation of multi-component aggregates according to the preset ratio.

[0010] Existing mixing devices lack a hierarchical ratio strategy for mixing uniformity, and the fixed ratio is difficult to cope with different aggregate characteristics or process requirements. For example, too high or too low proportion of coarse aggregate may lead to uneven mixing, but the traditional system cannot automatically adjust the ratio according to real-time quality data. It is necessary to establish a multi-level ratio scheme and a threshold trigger mechanism to achieve intelligent dynamic switching of the ratio strategy and improve the stability of mixing quality.

[0011] A single flow sensor has insufficient reliability in scenarios of high wear and fluctuating material characteristics, and is prone to measurement deviation or blockage problems. For example, a Coriolis flowmeter may be affected by density changes, and an ultrasonic sensor is susceptible to fluid viscosity interference. The traditional design lacks redundant calibration and anti-blocking means. It is necessary to improve the flow measurement accuracy and the anti-interference ability of the feeding system through multi-sensor redundancy, data fusion, and dynamic anti-blocking control.

[0012] Traditional quality inspection methods cannot evaluate the mixing quality in real time and comprehensively, and lack online monitoring of the particle distribution uniformity and moisture content. For example, manual sampling analysis is lagging and cannot capture instantaneous defects during the discharging process, and abnormal moisture content may lead to segregation of concrete. It is necessary to realize multi-dimensional real-time monitoring of the mixing quality through multi-spectral imaging and spectral detection technologies to provide accurate basis for adjusting mixing parameters.

[0013] Dust in the mixing environment is likely to contaminate the optical path of the detection module, resulting in blurred images or attenuated spectral signals, affecting the quality detection accuracy. The traditional dust-proof design relies on manual cleaning, which is inefficient and cannot meet the requirements of continuous production. It is necessary to reduce dust adhesion and achieve automatic cleaning through self-cleaning air curtains and dust-proof structure design to ensure the long-term stable operation of the detection module.

[0014] To achieve these and other advantages of the present invention, a sand and gravel aggregate mixing and stirring device is provided, including: A horizontal stirring cylinder, which is internally provided with multiple layers of stirring paddle groups. The two ends of the stirring cylinder are supported by bearings, and one end is connected to a driving motor. A cooling spray component is installed in the stirring cylinder; A stirring control system, which includes a central controller and multiple temperature sensors and multiple pressure sensors installed on the inner wall of the stirring cylinder. The temperature sensors are used to monitor the material temperature during the stirring process, and the pressure sensors are used to detect the pressure of the material on the inner wall of the stirring cylinder. The central controller controls the rotation speed of the driving motor and the start and stop of the cooling spray component according to preset temperature and pressure thresholds. Among them, when the temperature or pressure exceeds the threshold, the motor speed is reduced and the spray device is started; The feeding system includes multiple storage bins, with an electric feeding valve connected to the bottom of each storage bin. The electric valve is connected to a feeding pipe, and the feeding pipe is connected to the mixing drum. The electric feeding valve is connected to the central controller, and the central controller controls the opening time and opening degree of each electric feeding valve according to the preset ratio of sand and gravel aggregates. The quality detection and feedback system is arranged at the discharge port of the mixing drum. The quality detection and feedback system is used to take real-time pictures of the discharged material and judge the mixing uniformity of the sand and gravel aggregates through an image analysis algorithm. The quality detection and feedback system is connected to the central controller. Among them, if it is detected that the sand and gravel aggregates are not evenly mixed, an uneven signal is fed back to the central controller. The central controller receives the signal and adjusts the opening degree of the feeding valve and the rotation speed of the drive motor in the mixing system to achieve closed-loop control of the mixing process.

[0015] Preferably, the feeding system further includes: Multiple flow sensors, which are respectively installed in multiple feeding pipes. The flow sensors are connected to the central controller and are used to detect the flow data of the corresponding materials in real time and transmit them to the central controller. A diversion conical buffer section is arranged between the bottom outlet of each storage bin and the electric feeding valve, and a polymer wear-resistant coating is attached to the inner wall of the diversion conical buffer section. A high-frequency micro-vibrator is fixed at the outlet flange of each electric feeding valve, with a vibration frequency of 50 - 200 Hz and an adjustable amplitude. The high-frequency micro-vibrator is connected to the central controller. Among them, the central controller is configured to: calculate the theoretical flow of each material according to the preset ratio, and generate a deviation signal in combination with the real-time data of the flow sensor; when the deviation signal exceeds the allowable range, dynamically adjust the opening degree of the electric feeding valve and the amplitude of the high-frequency micro-vibrator until the error between the flow data detected by the flow sensor and the theoretical flow is ≤ 2%; according to the mixing uniformity result of the quality detection and feedback system, automatically select a pre-stored multi-level ratio scheme and synchronously update the opening sequence of the electric feeding valve.

[0016] Preferably, at least two mass ratios of sand and gravel aggregates are pre-stored in the central controller, including a dominant ratio of coarse aggregates, an enhanced ratio of fine aggregates, and an initial ratio. Wherein, the central controller is further configured to: compare the numerical value of the mixing uniformity feedback by the quality detection and feedback system with a preset first threshold and a second threshold, wherein the first threshold < the second threshold; when the numerical value of the mixing uniformity is lower than the first threshold, select the fine aggregate enhancement ratio and shorten the opening interval time of the electric feeding valve corresponding to the coarse aggregate; when the numerical value of the mixing uniformity is between the first threshold and the second threshold, maintain the initial ratio; when the numerical value of the mixing uniformity is higher than the second threshold, automatically select the coarse aggregate dominant ratio and extend the single opening duration of the electric feeding valve corresponding to the coarse aggregate; the opening timing of the electric feeding valve is synchronously updated at the start of the next feeding cycle.

[0017] Preferably, the flow sensor includes: A Coriolis mass flowmeter, which has a U-shaped tubular structure, is vertically installed in the middle of the straight section of each feed pipe, the inner wall is covered with a silicon nitride wear-resistant coating, and the inlet end of the U-shaped pipe is inclined at an angle of 15° - 30° with the horizontal direction; A redundant calibration module, which includes an ultrasonic flow sensor and an annular electrode array. The ultrasonic flow sensor is embedded in the inner wall of the feed pipe downstream of the Coriolis mass flowmeter, and emits pulsed ultrasonic waves with a frequency of 1 MHz - 5 MHz. The annular electrode array is coaxially wound around the outer wall of the feed pipe, and detects the dielectric constant of the material by detecting the change in capacitance; Wherein, the central controller is further configured to: a) Perform mean fusion on the detection data of the Coriolis mass flowmeter and the ultrasonic flow sensor, output the weighted average value when the deviation between the two is ≤ 3%, and preferentially use the ultrasonic flow data when the deviation > 3%; b) Dynamically adjust the density compensation coefficient of the Coriolis mass flowmeter according to the change amount of the dielectric constant detected by the annular electrode array; c) When the material flow rate in the feed pipe continuously remains below 80% of the preset threshold for 10 seconds, control the electric feeding valve to operate in an intermittent opening and closing mode, with an opening and closing frequency of 2 times per second and a single opening duration of 50 - 200 ms.

[0018] Preferably, the quality detection and feedback system includes: A multi-spectral imaging module, which is arranged obliquely above the side of the discharge port of the mixing drum, at an angle of 30° - 45° with the vertical direction. The multi-spectral imaging module includes a polarized industrial camera and a short-wave infrared spectrometer. The polarized industrial camera is used to collect the polarized light image of the material falling trajectory and identify the surface reflection characteristics of sand and gravel particles. The wavelength range of the short-wave infrared spectrometer is 1.4 - 2.0 μm, and it detects the moisture content distribution inside the aggregate. Among them, the central controller is further configured to: calculate the coefficient of variation of sand, stone, and cement according to the difference in the reflected light intensity of particles in the polarized light image, and determine that the mixing is uneven when the coefficient of variation > 0.25; if the short-wave infrared spectroscopy detects that the moisture content range > 5%, a warning signal is triggered and the driving motor speed is reduced to 70%-80% of the rated value.

[0019] Preferably, the quality detection and feedback system further includes: A reflection deflector, which is made of high-transparency wear-resistant glass, the reflection deflector has a semi-enclosed arc-shaped structure, covers the outside of the multispectral imaging module, and a hydrophobic nano-coating is provided on the inner surface of the reflection deflector; A self-cleaning air curtain unit, including a plurality of compressed air nozzles, the plurality of compressed air nozzles are evenly distributed in a ring along the edge of the reflection deflector, the distance between adjacent nozzles is 50-100 mm, and the axis of the nozzle forms an inclination angle of 15°-30° with the tangent direction of the outer surface of the reflection deflector, and the injection direction of the compressed air nozzle forms an angle of 10°-20° with the vertical direction, forming an isolation air curtain covering the outer surface of the reflection deflector; Among them, the central controller is further configured to: after each discharge cycle is completed, control the nozzles in the self-cleaning air curtain unit to spray compressed air at 0.5-0.8 MPa for 2-3 seconds to remove the dust attached to the surface of the reflection deflector.

[0020] Preferably, each layer of stirring blade group is composed of a plurality of stirring blades, and the plurality of stirring blades are staggered along the axial direction of the stirring cylinder. In the material moving direction, the multi-layer stirring blades near the feed pipe are straight blades, the multi-layer stirring blades in the middle of the stirring cylinder are the middle layer, the middle layer stirring blades are curved, and the remaining stirring blades are the outermost layer stirring blades, and the outermost layer stirring blades are serrated.

[0021] The present invention has at least the following beneficial effects: First, the present invention constructs a "detection - control - feedback" full-process closed-loop system through the central controller linking multiple sensors (temperature, pressure, flow rate, multispectral imaging, etc.). For example, according to the real-time data of temperature and pressure in the stirring cavity, the motor speed and cooling spray are dynamically adjusted to avoid equipment overload and material overheating and caking; the feeding system realizes high-precision ratio control through a flow sensor and a high-frequency micro-vibrator, and automatically switches in combination with a multi-stage ratio scheme to adapt to different aggregate gradation requirements; the quality detection module evaluates the mixing uniformity and moisture content in real time through polarized light images and short-wave infrared spectroscopy, and triggers parameter correction to ensure the stability of the discharge quality. This mechanism reduces manual intervention and improves production efficiency, especially suitable for scenarios sensitive to the mixing accuracy of aggregates such as high-performance concrete.

[0022] Second, the multi-layer paddle partition design (straight blade propulsion, curved blade shearing, serrated blade crushing) inside the horizontal mixing drum, combined with the axial staggered layout, eliminates the mixing blind spots and enhances the mixing efficiency and uniformity of multi-sized aggregates; the structural designs such as the diversion conical buffer section, wear-resistant coating, and self-cleaning air curtain reduce the impact wear of materials, prevent dust pollution of the detection module, and extend the service life of the equipment; the designs such as the redundant calibration of the flow sensor and the anti-blocking high-frequency opening and closing valve improve the anti-interference ability of the system in high-humidity and high-dust environments and ensure continuous and stable operation. The overall structure takes into account both the mixing performance and the equipment durability, meeting the requirements of complex working conditions in construction projects.

[0023] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of the sand and gravel aggregate mixing and stirring device according to one of the technical solutions of the present invention; Figure 2 It is a schematic structural diagram of the intermediate layer paddle according to one of the technical solutions of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0025] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0026] As Figure 1-2 shown, the present invention provides a sand and gravel aggregate mixing and stirring device, including: A horizontal mixing drum 1, which is internally provided with a multi-layer mixing paddle group, and both ends of the mixing drum 1 are supported by bearings, one end is connected to a driving motor 2, and a cooling spray assembly is installed inside the mixing drum 1; A mixing control system, which includes a central controller and a plurality of temperature sensors and a plurality of pressure sensors installed on the inner wall of the mixing drum 1. The temperature sensors are used to monitor the material temperature during the mixing process, and the pressure sensors are used to detect the pressure of the material on the inner wall of the mixing drum 1. The central controller controls the rotation speed of the driving motor 2 and the start and stop of the cooling spray assembly according to the preset temperature and pressure thresholds. Among them, when the temperature or pressure exceeds the threshold, the motor speed is reduced and the spray device is started; A feeding system, which includes a plurality of storage bins 7, an electric feeding valve is connected to the bottom of each storage bin 7, the electric valve 9 is communicated with a feeding pipe 10, the feeding pipe 10 is communicated with the mixing drum 1, the electric feeding valve is connected to the central controller, and the central controller controls the opening time and opening degree of each electric feeding valve according to the preset sand and gravel aggregate ratio; The quality detection and feedback system is arranged at the discharge port of the mixing drum 1. The quality detection and feedback system is used to take real-time pictures of the discharged material and judge the mixing uniformity of the sand and gravel aggregate through an image analysis algorithm. The quality detection and feedback system is connected to the central controller. Among them, if it is detected that the sand and gravel aggregate is not evenly mixed, an uneven signal will be fed back to the central controller. The central controller receives the signal and adjusts the opening of the feeding valve and the rotation speed of the driving motor 2 in the mixing system to achieve closed-loop control of the mixing process.

[0027] In this technical solution, the mixing drum 1 is installed on the support frame. The mixing drum 1 is inclined, and the discharge port of the mixing drum 1 is located at the lower end. A rotating shaft 3 is provided inside the mixing drum 1 (mixing blades are arranged on the rotating shaft 3). The two ends of the rotating shaft 3 can be supported by deep groove ball bearings or spherical roller bearings. The driving motor 2 connected to one end of the rotating shaft 3 can be a three-phase asynchronous motor, and the power can be selected between several kilowatts and dozens of kilowatts according to the size of the mixing drum 1. The cooling spray assembly installed inside the mixing drum 1, and the spray nozzles can be spiral nozzles or fan-shaped nozzles, which can effectively achieve the spray cooling function. The blades of the mixing blade group can be straight blades, curved blades or blades with serrations. Different shaped blades are suitable for different mixing stages. The mixing blades can be installed in a staggered distribution along the axial direction of the mixing drum 1 to enhance the mixing effect. The mixing control system includes a central controller, and the central controller can be a PLC (Programmable Logic Controller). The temperature sensor installed on the inner wall of the mixing drum 1 can be a thermocouple sensor or a thermal resistance sensor, and the pressure sensor can be a strain type pressure sensor or a piezoresistive pressure sensor. The central controller controls according to the preset temperature and pressure thresholds. When the temperature exceeds 40 - 60 °C or the pressure exceeds 0.3 - 1.0 MPa (the specific settings can be adjusted according to the properties of the materials used), the motor speed is reduced and the cooling spray assembly is started. The electric feed valve connected to the bottom of each storage bin 7 can be an electric butterfly valve or an electric ball valve, and these valves can accurately control the feeding amount. The electric feed valve is connected to the central controller, and the central controller controls the opening time and opening degree of each electric feed valve according to the preset sand and gravel aggregate ratio. For example, for sand and gravel aggregates of different particle sizes, the central controller can control the opening duration and valve opening degree of the corresponding electric feed valve according to the preset ratio. The quality inspection and feedback system is arranged at the discharge port of the mixing drum 1. The device for taking real-time pictures of the discharged material can be an industrial camera. The mixing uniformity of the sand and gravel aggregates is judged through an image analysis algorithm, and the image analysis algorithm can adopt analysis methods based on color features, texture features, etc. This system is connected to the central controller. If it is detected that the sand and gravel aggregates are not evenly mixed, the uneven signal is fed back to the central controller. The central controller receives the signal and adjusts the opening degree of the feed valve and the speed of the driving motor 2 in the mixing system to achieve closed-loop control of the mixing process. The parameters of the image analysis algorithm can be determined by analyzing and training the images of a large number of standard mixed samples to improve the accuracy of judgment; when the result detected by one of the pressure sensors or one of the temperature sensors exceeds the preset threshold, the central controller drives the motor 2 to reduce the speed and starts the cold spray assembly at the same time.

[0028] In use, first preset the parameters in the central controller according to the required sand and gravel aggregate ratio. The materials in each storage bin 7 enter the horizontal mixing drum 1 through the feeding pipe 10 via the electric feeding valve according to the set opening time and opening degree. The driving motor 2 drives the multi-layer mixing paddle group in the mixing drum 1 to rotate and mix the materials. During the mixing process, the temperature sensor and the pressure sensor monitor the temperature of the materials in the drum and the pressure on the drum wall in real time, and transmit the data to the central controller. If the temperature or pressure exceeds the preset threshold, the central controller controls the driving motor 2 to reduce the speed and simultaneously starts the cooling spray assembly to spray water for cooling. When discharging, the quality inspection and feedback system takes real-time pictures of the discharged materials through an industrial camera, and judges the mixing uniformity through an image analysis algorithm. If it detects uneven mixing, it will feedback the signal to the central controller. The central controller adjusts the opening degree of the feeding valve and the speed of the driving motor 2, and realizes parameter correction in the next mixing cycle to form a closed-loop control.

[0029] Adopting this technical solution, the sand and gravel aggregate mixing and stirring device of the present invention can effectively improve the mixing efficiency of sand and gravel aggregates through the synergistic effect of the multi-layer mixing paddle group. The staggered paddle structure can reduce the mixing blind area and make the material mixing more uniform. The linkage control of the temperature and pressure sensors and the central controller can monitor the stirring working condition in real time, avoid equipment overload or material performance deterioration caused by too high temperature or too large pressure, and improve the safety and stability of the stirring process. The feeding system is based on the precise control of the preset ratio, combined with the closed-loop regulation of the quality inspection and feedback system, can dynamically correct the feeding parameters and stirring parameters, significantly improve the accuracy and uniformity of the aggregate mixing ratio, reduce manual intervention, adapt to different process requirements, provide high-quality mixed aggregates for construction projects, and help improve the performance and construction quality of building materials such as concrete.

[0030] In another technical solution, the feeding system further includes: A plurality of flow sensors, which are respectively installed in a plurality of feeding pipes 10, and the flow sensors are connected to the central controller for detecting the flow data of the corresponding materials in real time and transmitting them to the central controller; A diversion conical buffer section 8 is arranged between the bottom outlet of each storage bin 7 and the electric feeding valve, and the inner wall of the diversion conical buffer section is attached with a polymer wear-resistant coating; A high-frequency micro-vibrator is fixed at the outlet flange of each electric feeding valve, with a vibration frequency of 50 - 200 Hz and an adjustable amplitude, and the high-frequency micro-vibrator is connected to the central controller; The central controller is configured to calculate the theoretical flow of each material according to the preset ratio, and generate a deviation signal in combination with the real-time data of the flow sensor; when the deviation signal exceeds the allowable range, dynamically adjust the opening of the electric feeding valve and the amplitude of the high-frequency micro-vibrator until the error between the flow data detected by the flow sensor and the theoretical flow is ≤2%; according to the mixing uniformity result of the quality inspection and feedback system, automatically select the pre-stored multi-level ratio scheme, and synchronously update the opening timing of the electric feeding valve. Flow sensors are installed one by one in the multiple feeding pipes 10 of the feeding system, and the flow sensors detect the flow data of the corresponding materials in real time and transmit them to the central controller. Under the preset ratio, the central controller dynamically adjusts the opening of the electric feeding valve (such as an electric gate valve or an electric regulating valve) and the amplitude of the high-frequency micro-vibrator according to the deviation between the theoretical flow and the real-time flow (such as the allowable range is set to ±3%). The high-frequency micro-vibrator can be an electromagnetic or piezoelectric vibrator, the vibration frequency range is set to 50-200Hz, the amplitude can be adjusted in the range of 0.1-2mm, and it is installed at the outlet flange of the electric feeding valve and fixed by bolts. The upper diameter of the guide cone buffer section is large and the lower diameter is small. The guide cone buffer section 8 is installed between the outlet of the storage bin 7 and the electric feeding valve by flange connection. Its function is to guide the material to fall smoothly and reduce the impact and turbulence during feeding. During operation, the material enters the buffer section from the storage bin 7 and flows into the electric feeding valve evenly after the cone diversion, avoiding material accumulation or sudden change of flow rate caused by right-angle feeding. The calibration method of the flow sensor can adopt the standard volumetric method, and regularly compare and calibrate with fluids of known flow. With this technical solution, the present invention can monitor the material flow in real time and link with the central controller by arranging a flow sensor in the feed pipe 10, calculate the deviation between the theoretical flow and the actual flow in combination with the preset ratio, dynamically adjust the opening of the electric feeding valve and the amplitude of the high-frequency micro-vibrator, and control the flow error to ≤2%, significantly improve the feed ratio accuracy, and reduce the feeding fluctuation caused by changes in material humidity and particle size. The inner wall of the diversion cone buffer section is provided with a polymer wear-resistant coating (such as polyurethane), which can optimize the material flow path, reduce the impact of material discharge and reduce the wear of the pipe wall, thus extending the service life of the equipment; a high-frequency micro-vibrator (vibration frequency 50-200Hz) is installed at the outlet of the electric feeding valve, which can effectively prevent material agglomeration and blockage through adjustable amplitude vibration, which is especially suitable for high-humidity fine aggregate scenes to ensure feeding continuity. In addition, the central controller automatically switches the multi-stage proportioning scheme and updates the feeding sequence according to the quality inspection results, and can dynamically adjust the feeding strategy according to the mixing uniformity, avoiding the interference of real-time adjustment on the current mixing process, improving the system's adaptability to complex working conditions, and ensuring the stability of mixing quality under different aggregate grading requirements.

[0031] In another technical solution, at least two mass ratios of sand and gravel aggregates are pre-stored in the central controller, including a dominant ratio of coarse aggregates (the proportion of coarse aggregates can be set to 65% and the proportion of fine aggregates is 35%), an enhanced ratio of fine aggregates (the proportion of fine aggregates is 55% and the proportion of coarse aggregates is 45%), and an initial ratio (each of the coarse and fine aggregates accounts for 50%); Among them, the central controller is further configured to: compare the mixing uniformity value fed back by the quality detection and feedback system with a preset first threshold and a second threshold, where the first threshold < the second threshold; when the mixing uniformity value is lower than the first threshold, select the enhanced ratio of fine aggregates and shorten the opening interval time of the electric feeding valve corresponding to the coarse aggregates; when the mixing uniformity value is between the first threshold and the second threshold, maintain the initial ratio; when the mixing uniformity value is higher than the second threshold, automatically select the dominant ratio of coarse aggregates and extend the single opening duration of the electric feeding valve corresponding to the coarse aggregates; the opening timing of the electric feeding valve is synchronously updated at the start of the next feeding cycle. The central controller compares the mixing uniformity value (discrete coefficient calculated by the image analysis algorithm) fed back by the quality detection with a preset first threshold (such as discrete coefficient 0.3) and a second threshold (such as discrete coefficient 0.2): when the value is lower than the first threshold, select the dominant ratio of coarse aggregates and shorten the opening interval time of the electric feeding valve corresponding to the coarse aggregates (such as adjusting from opening once every 10 seconds to opening once every 8 seconds); when it is between the thresholds, maintain the initial ratio; when it is higher than the second threshold, select the enhanced ratio of fine aggregates and extend the single opening duration of the fine aggregate valve (such as extending from opening for 5 seconds each time to opening for 8 seconds). The ratio adjustment signal is synchronously updated at the start of the next feeding cycle (such as a mixing cycle is 3 minutes) (after the current cycle discharges and the mixing drum stops running, the new parameters are applied at the start of the next cycle). ，When switching cycles, reserve a 5-second buffer time to ensure that the materials in the current mixing drum are completely discharged. After the equipment enters the standby state, start the next cycle to avoid interfering with the current mixing process. The opening sequence update mechanism of the electric feeding valve is as follows: after receiving the quality detection feedback signal, the central controller stores the ratio adjustment instruction to be executed in the next feeding cycle (i.e., when the current mixing cycle ends and the next cycle starts), and sets a transition buffer time (such as 5 seconds). For example, if the remaining time of the current cycle is 2 minutes, the adjustment instruction will not take effect temporarily. When the next cycle starts, each valve operates according to the opening time and interval of the new ratio. If the adjustment range is large (such as the ratio switching exceeds 20%), the central controller will gradually adjust the opening degree of the electric feeding valve and the motor speed in stages, with an adjustment interval of 10 seconds for each stage until the target parameters are reached. This design avoids the material impact or mixing load fluctuation caused by suddenly changing the feeding amount during the mixing process and ensures the continuity of the mixing process. The timing control is achieved through the timer function of the central controller. With this technical solution, the present invention pre-stores multi-level schemes such as the dominant ratio of coarse aggregate, the enhanced ratio of fine aggregate, and the initial ratio. The central controller can intelligently switch the ratio strategy according to the comparison result between the mixing uniformity value (such as the coefficient of variation) detected by the quality detection feedback and the preset thresholds (the first threshold < the second threshold). This design can dynamically respond to the change of mixing quality, adapt to different aggregate characteristics and mixing requirements, reduce manual intervention, improve the flexibility of the ratio strategy and the stability of the mixing quality, and is especially suitable for the preparation scenario of high-performance concrete sensitive to aggregate gradation.

[0032] In another technical solution, the flow sensor includes: A Coriolis mass flowmeter, which has a U-shaped tubular structure and is vertically installed in the middle of the straight section of each feed pipe 10. The inner wall is covered with a silicon nitride wear-resistant coating, and the inlet end of the U-shaped pipe forms an inclination angle of 15° - 30° with the horizontal direction. The inclination angle between the inlet end of the U-shaped pipe and the horizontal direction can be set to 15°, 20°, 25°, or 30° to reduce material retention. The vertical straight section length of the feed pipe needs to be ≥ 10 times the pipe diameter. The Coriolis mass flowmeter can be installed on a shock-absorbing bracket or adopt another shock-absorbing method, that is, the connecting section between the feed pipe and the Coriolis mass flowmeter uses a stainless steel bellows flexible connector (material: SUS304, pressure resistance grade ≥ 1.6 MPa, axial compensation amount ± 5 mm) to absorb the mechanical vibration generated by the high-frequency micro-vibrator (50 - 200 Hz) through elastic deformation and reduce the influence of vibration transmission on the measurement accuracy of the flowmeter. The inner wall of the flexible connector is coated with a polymer wear-resistant coating (such as polyurethane, thickness 1.5 mm) to avoid wear caused by the flow of sand and gravel aggregates. During installation, it is necessary to ensure that the bellows is coaxial with the pipeline, and the pre-tightening torque of the flange bolts is 20 - 25 N·m to prevent seal failure caused by eccentric load; A redundant calibration module, which includes an ultrasonic flow sensor and an annular electrode array. The ultrasonic flow sensor is embedded in the inner wall of the feed pipe 10 downstream of the Coriolis mass flowmeter, and emits pulsed ultrasonic waves with a frequency of 1 MHz - 5 MHz (pulsed ultrasonic waves with frequencies of 1 MHz, 2 MHz, 3 MHz, 4 MHz, or 5 MHz). The annular electrode array coaxially surrounds the outer wall of the feed pipe 10, and detects the dielectric constant of the material through capacitance changes (such as the dielectric constant difference between sand and water); Wherein, the central controller is further configured to: a) Perform mean fusion on the detection data of the Coriolis mass flowmeter and the ultrasonic flow sensor, and output the weighted average when the deviation between the two is ≤ 3%, and preferentially use the ultrasonic flow data when the deviation > 3%; b) Dynamically adjust the density compensation coefficient of the Coriolis mass flowmeter according to the change in the dielectric constant detected by the annular electrode array. The adjustment formula for the density compensation coefficient is: compensation coefficient = initial coefficient × (1 + dielectric constant change amount × 0.1), which is determined through experiments on the linear relationship between the dielectric constant and density of the material.

[0033] c) When the material flow rate in the feed pipe 10 continuously remains below 80% (i.e., 0.4 m / s) of the preset threshold (such as 0.5 m / s) for 10 seconds, the central controller controls the electric feed valve to operate in an intermittent opening and closing mode. The opening and closing frequency is set to 2 times per second, and the single - opening duration is 50 ms, 100 ms, 150 ms, or 200 ms. For example, select a combination of a frequency of 3 times per second and a duration of 100 ms, and generate pulsed impact force through rapid opening and closing to break the agglomeration or adhesion state of the material and restore the normal flow rate. The operation duration of this mode can be set to 30 seconds. If the flow rate still does not recover, an alarm is triggered. The preset flow rate threshold is determined according to the diameter of the feed pipe 10 and the material characteristics. For example, the flow rate threshold of sand material with a φ50 mm diameter pipe can be set to 0.8 m / s, which is determined through fluid mechanics calculations and experimental verification. With this technical solution, the present invention improves the reliability of flow measurement through the redundant configuration and data fusion of the Coriolis mass flowmeter and the ultrasonic flow sensor: when the deviation between the two is ≤ 3%, the weighted average is taken; when > 3%, the ultrasonic data is preferentially used. Combining the detection of the dielectric constant by the annular electrode array to dynamically compensate the density parameter to adapt to the fluctuation of material characteristics. When the flow rate is low, control the electric feed valve to open and close frequently (2 - 5 times per second) to effectively break the agglomeration and blockage and ensure the continuity of feeding. Multiple technologies cooperate to achieve accurate flow monitoring and anti - block control, improve the adaptability of the feeding system to high - humidity and easily agglomerated materials, and ensure the proportioning accuracy and production stability.

[0034] In another technical solution, the quality detection and feedback system includes: A multi-spectral imaging module is disposed obliquely above and laterally of the discharge port of the mixing drum 1, with an angle of 30°-45° to the vertical direction (the angle to the vertical direction is set to 30°, 35°, 40° or 45°), the multi-spectral imaging module includes a polarization industrial camera and a short-wave infrared spectrometer, the polarization industrial camera is used to collect polarized light images of the material falling trajectory, and identify the surface reflective properties of sand and gravel particles, the wavelength range of the short-wave infrared spectrometer is 1.4-2.0μm (the wavelength range can reduce the interference of other substances and reflect the absorption of water, thereby achieving more accurate detection of the internal moisture content of the aggregate, and the light in the 1.4-2.0μm band has better penetration and scattering characteristics than the light in other bands when passing through the material), and detects the internal moisture content distribution of the aggregate; The central controller is further configured to calculate the discrete coefficients of sand, stone and cement according to the difference in the reflective intensity of particles in the polarized light image (such as the difference in the reflective rate of sand and stone>20%) (when calculating the discrete coefficient, the image is divided into 10×10 pixel grids, the standard deviation of the reflective intensity is calculated in each grid, and the average value of the whole image is taken as the discrete coefficient). When the discrete coefficient is>0.25, it is judged that the mixing is uneven; if the short-wave infrared spectrum detects that the moisture content range is>5%, the warning signal is triggered and the speed of the drive motor 2 is reduced to 70%-80% of the rated value (such as the rated speed of 100r / min is reduced to 75r / min) to slow down the stirring and avoid the intensification of moisture migration. The angle between the lens axis of the polarized industrial camera and the direction of material falling is set to 45°, and a polarizing filter is equipped to eliminate ambient light interference. The detection window of the short-wave infrared spectrometer is kept 30-50cm away from the surface of the material to ensure the intensity of the spectral signal. During operation, the material falls from the discharge port to form a parabolic trajectory. The imaging module synchronously collects images and spectral data from the upper side and transmits them to the central controller through a data line for real-time analysis. Using this technical solution, the present invention realizes multi-dimensional monitoring of mixing quality through a multi-spectral imaging module: a polarized industrial camera collects polarized light images, analyzes the difference in particle reflection intensity, calculates the discrete coefficient (>0.25 is considered uneven), and accurately identifies the uniformity of aggregate distribution; a short-wave infrared spectrometer (wavelength 1.4-1.8μm) detects the extreme difference in moisture content (>5% triggers an early warning and slows down) to prevent quality defects caused by uneven moisture. The 30°-45° installation angle from the upper side covers the entire trajectory of the material falling, and combines the image and spectral data for linkage control to improve the real-time and comprehensiveness of mixing quality detection, provide a reliable basis for adjusting mixing parameters, and ensure aggregate mixing accuracy and performance stability.

[0035] In another technical solution, the quality detection and feedback system further includes: A reflective air guide cover is made of high-transmittance wear-resistant glass. The reflective air guide cover is a semi-enclosed arc structure, covering the outside of the multi-spectral imaging module. The inner surface of the reflective air guide cover is provided with a hydrophobic nano coating (such as a silica-based coating) with a contact angle of ≥110° to reduce dust adhesion. The coating wear resistance grade meets the ASTM D4060 standard and has a service life of ≥5000 cleaning cycles; The self-cleaning air curtain unit includes multiple compressed air nozzles, which are evenly distributed in a ring along the edge of the reflective guide cover, with adjacent spacing of 50mm, 75mm or 100mm, and the angle between the nozzle axis and the tangent of the cover surface is 15°, 20° or 25°, and the angle between the spray direction and the vertical direction is 10°, 15° or 20°, forming an annular isolation air curtain. The compressed air pressure is set to 0.5-0.8MPa, and the spray is 2-3 seconds after each discharging cycle. The air flow speed can reach 20-30m / s, which can effectively blow away the surface dust; Among them, the central controller is further configured to: after each discharge cycle is completed, control the nozzle in the self-cleaning air curtain unit to spray 0.5-0.8MPa compressed air for 2-3 seconds to remove the dust attached to the surface of the reflective guide cover. The coating process of the hydrophobic nano coating adopts the magnetron sputtering method, and the coating thickness is controlled at 50-100nm. The hydrophobic performance is detected by the contact angle meter. After each discharge cycle (such as 5 minutes), the spraying is delayed for 10 seconds to avoid conflict with the discharge process. The design of the nozzle spray direction ensures that the airflow flows along the tangential direction of the cover surface, forming an "air knife" effect, blowing away the dust particles along the tangential direction, rather than vertical impact to cause dust diffusion. The compressed air for the air curtain spray can come from the air compressor of the equipment, and is used after being filtered by the oil-water separator to ensure gas cleanliness. The optimization of the nozzle spacing and the spray angle is determined by computational fluid dynamics (CFD) simulation to achieve the maximum cleaning coverage area with minimum energy consumption. By adopting this technical solution, the present invention effectively blocks dust adhesion through the combination of a reflective guide cover (high-transmittance wear-resistant glass + hydrophobic coating) and a self-cleaning air curtain (compressed air nozzles evenly distributed in a ring). After each cycle, the surface dust is automatically cleared by blowing (0.5-0.8MPa air pressure for 2-3 seconds), ensuring the long-term and stable operation of the multi-spectral imaging module, avoiding contamination of the detection optical path, and improving the reliability of mixed quality detection and the level of equipment automation maintenance.

[0036] In another technical solution, each layer of stirring paddle group is composed of multiple paddles, which are staggeredly distributed along the axial direction of the mixing drum 1. The multiple paddles close to the feed pipe 10 are the inner paddles 4, which adopt a straight blade structure. The material can be selected from 45# steel or stainless steel, and the surface is quenched to push the material to quickly move towards the middle of the mixing drum 1; the middle intermediate layer paddle 5 is curved (such as a spiral blade with a pitch of 150 - 200 mm), and the material can be selected from stainless steel or wear-resistant cast iron, and the lateral shearing and mixing of the material are enhanced through the curved surface design; the outermost paddle 6 is serrated (tooth height 5 - 10 mm, tooth pitch 20 - 30 mm), and the material is made of high-chromium cast iron, which is used to break up agglomerated materials and increase the surface friction of particles. The installation angle of the paddle: the straight blade is perpendicular to the axis of the mixing drum 1, the spiral angle of the curved blade is set at 30° - 45°, the serration direction of the serrated blade is the same as the rotation direction (tilted forward 10° - 15°). The selection of the paddle material is determined according to the degree of wear. The straight blade at the feed end can be selected as stainless steel due to the large impact of the material, and the middle and outer paddles can be selected from wear-resistant cast iron or high-chromium cast iron. With this technical solution, the straight blade at the feed end of the present invention pushes the material to move quickly, the middle curved blade enhances the lateral shearing and mixing, and the outer serrated blade breaks up agglomerates and strengthens the friction; the axial staggered distribution of the paddles reduces the mixing blind area, and the multiple structures cooperate to adapt to aggregates of multiple particle sizes, improving the mixing efficiency and uniformity, reducing energy consumption and extending the wear life of the equipment.

[0037] The equipment quantities and processing scales described here are used to simplify the description of the present invention. The application, modification, and variation of the sand and gravel aggregate mixing and stirring device of the present invention are obvious to those skilled in the art.

[0038] Although the embodiments of the present invention have been disclosed as above, it is not limited to only the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details and the illustrated and described examples here.

Claims

1. Sand and gravel aggregate mixing and stirring device, characterized in that Including: A horizontal mixing drum, which is internally provided with multiple layers of mixing paddle groups. Both ends of the mixing drum are supported by bearings, and one end is connected to a driving motor. A cooling spray assembly is installed inside the mixing drum; A mixing control system, which includes a central controller and multiple temperature sensors and multiple pressure sensors installed on the inner wall of the mixing drum. The temperature sensors are used to monitor the temperature of the materials during the mixing process, and the pressure sensors are used to detect the pressure of the materials on the inner wall of the mixing drum. The central controller controls the rotation speed of the driving motor and the start and stop of the cooling spray assembly according to preset temperature and pressure thresholds. Among them, when the temperature or pressure exceeds the threshold, the motor speed is reduced and the spray device is started; A feeding system, which includes multiple storage bins. An electric feeding valve is connected to the bottom of each storage bin. The electric valve is connected to a feeding pipe, and the feeding pipe is connected to the mixing drum. The electric feeding valve is connected to the central controller. The central controller controls the opening time and opening degree of each electric feeding valve according to a preset sand and gravel aggregate ratio; A quality detection and feedback system, which is arranged at the discharge port of the mixing drum. The quality detection and feedback system is used to take real-time pictures of the discharged materials and judge the mixing uniformity of the sand and gravel aggregates through an image analysis algorithm. The quality detection and feedback system is connected to the central controller. Among them, if it is detected that the sand and gravel aggregates are not evenly mixed, an uneven signal is fed back to the central controller. The central controller receives the signal and adjusts the opening degree of the feeding valve and the rotation speed of the driving motor in the mixing system to achieve closed-loop control of the mixing process.

2. The sand and gravel aggregate mixing and stirring device according to claim 1, wherein The feeding system further includes: Multiple flow sensors, which are respectively installed in multiple feeding pipes. The flow sensors are connected to the central controller and are used to detect the flow data of the corresponding materials in real time and transmit them to the central controller; A diversion conical buffer section, which is arranged between the bottom outlet of each storage bin and the electric feeding valve. The inner wall of the diversion conical buffer section is attached with a polymer wear-resistant coating; A high-frequency micro-vibrator, which is fixed at the outlet flange of each electric feeding valve, with a vibration frequency of 50 - 200 Hz and an adjustable amplitude. The high-frequency micro-vibrator is connected to the central controller; Among them, the central controller is configured to: calculate the theoretical flow of each material according to the preset ratio and generate a deviation signal in combination with the real-time data of the flow sensor; when the deviation signal exceeds the allowable range, dynamically adjust the opening degree of the electric feeding valve and the amplitude of the high-frequency micro-vibrator until the flow data detected by the flow sensor has an error of ≤ 2% from the theoretical flow; according to the mixing uniformity result of the quality detection and feedback system, automatically select a pre-stored multi-level ratio scheme and synchronously update the opening sequence of the electric feeding valve.

3. The sand and gravel aggregate mixing and stirring device according to claim 2, characterized in that, At least two sand and gravel aggregate mass ratios are pre-stored in the central controller, including a dominant ratio of coarse aggregates, an enhanced ratio of fine aggregates, and an initial ratio; Wherein, the central controller is further configured to: compare the numerical value of the mixing uniformity fed back by the quality detection and feedback system with a preset first threshold and a second threshold, wherein the first threshold < the second threshold; when the numerical value of the mixing uniformity is lower than the first threshold, select the fine aggregate enhancement ratio and shorten the opening interval of the electric feeding valve corresponding to the coarse aggregate; when the numerical value of the mixing uniformity is between the first threshold and the second threshold, maintain the initial ratio; when the numerical value of the mixing uniformity is higher than the second threshold, automatically select the coarse aggregate dominant ratio and extend the single opening duration of the electric feeding valve corresponding to the coarse aggregate; the opening timing of the electric feeding valve is synchronously updated at the start of the next feeding cycle.

4. The sand and gravel aggregate mixing and stirring device according to claim 3, characterized in that, The flow sensor includes: A Coriolis mass flowmeter, which has a U-shaped tubular structure and is vertically installed in the middle of the straight section of each feed pipe. The inner wall is covered with a silicon nitride wear-resistant coating, and the inlet end of the U-shaped pipe is inclined at an angle of 15° - 30° with the horizontal direction; A redundant calibration module, which includes an ultrasonic flow sensor and a ring electrode array. The ultrasonic flow sensor is embedded in the inner wall of the feed pipe downstream of the Coriolis mass flowmeter and emits pulsed ultrasonic waves with a frequency of 1 MHz - 5 MHz. The ring electrode array is coaxially wound around the outer wall of the feed pipe to detect the dielectric constant of the material by detecting the change in capacitance; Wherein, the central controller is further configured to: a) Perform mean fusion on the detection data of the Coriolis mass flowmeter and the ultrasonic flow sensor, and output the weighted average value when the deviation between the two is ≤ 3%. When the deviation > 3%, the ultrasonic flow data is preferentially used; b) Dynamically adjust the density compensation coefficient of the Coriolis mass flowmeter according to the change amount of the dielectric constant detected by the ring electrode array; c) When the material flow rate in the feed pipe continuously remains below 80% of the preset threshold for 10 seconds, control the electric feeding valve to operate in an intermittent opening and closing mode, with an opening and closing frequency of 2 times per second and a single opening duration of 50 - 200 ms.

5. The sand and gravel aggregate mixing and stirring device according to claim 1, characterized in that, The quality detection and feedback system includes: A multi-spectral imaging module, which is arranged obliquely above the side of the discharge port of the mixing drum at an angle of 30° - 45° with the vertical direction. The multi-spectral imaging module includes a polarized industrial camera and a short-wave infrared spectrometer. The polarized industrial camera is used to collect the polarized light image of the material falling trajectory and identify the reflective characteristics of the surface of sand and stone particles. The wavelength range of the short-wave infrared spectrometer is 1.4 - 2.0 μm, and it detects the moisture content distribution inside the aggregate; Wherein, the central controller is further configured to: calculate the dispersion coefficient of sand, stone, and cement according to the difference in particle reflection intensity in the polarized light image. When the dispersion coefficient > 0.25, it is determined that the mixing is uneven; if the moisture content range detected by the short-wave infrared spectrum > 5%, a warning signal is triggered and the driving motor speed is reduced to 70% - 80% of the rated value.

6. The sand and gravel aggregate mixing and stirring device according to claim 5, characterized in that, The quality detection and feedback system further includes: A reflection deflector, which is made of high-transparency wear-resistant glass. The reflection deflector has a semi-enclosed arc structure and covers the outside of the multi-spectral imaging module. The inner surface of the reflection deflector is provided with a hydrophobic nano-coating; Self-cleaning air curtain unit, including a plurality of compressed air nozzles, the plurality of compressed air nozzles are evenly distributed annularly along the edge of the reflection deflector, the distance between adjacent nozzles is 50-100 mm, and the axis of the nozzle forms an inclination angle of 15°-30° with the tangent direction of the outer surface of the reflection deflector, and the injection direction of the compressed air nozzle forms an angle of 10°-20° with the vertical direction, forming an isolation air curtain covering the outer surface of the reflection deflector; Wherein, the central controller is further configured to: after each discharging cycle is completed, control the nozzles in the self-cleaning air curtain unit to inject compressed air of 0.5-0.8 MPa for 2-3 seconds to remove the dust attached to the surface of the reflection deflector.

7. The sand and gravel aggregate mixing and stirring device according to claim 1, characterized in that, Each layer of stirring blade group is composed of a plurality of stirring blades, the plurality of stirring blades are staggered along the axial direction of the stirring cylinder, in the material moving direction, the multi-layer stirring blades close to the feed pipe are straight blades, the multi-layer stirring blades located in the middle of the stirring cylinder are the middle layer, the stirring blades in the middle layer are curved, the remaining stirring blades are the outermost layer stirring blades, and the outermost layer stirring blades are serrated.

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