Research On Weighing Device Of Symmetrical Belt Conveyor

The electronic belt scale is a measuring device for continuous weighing of materials during the process of conveying solid bulk materials on a belt conveyor.The complex structure of the weighing frame and low weighing accuracy are the main problems existing in the current electronic belt scale.In view of the above problems,this paper analyzes the characteristics of the different structure of the weighing frame,and designs a symmetrical structure of the belt conveyor weighing device.Low measurement accuracy The influencing factors of the error are analyzed,and the hysteresis of the load cell is modeled and optimized.Finally,the control variable method and multi-factor analysis method are used to verify the influencing factors of the weighing error of the electronic belt scale.Analyze the working principle of the symmetrical belt conveyor weighing device,combine the symmetrical weighing frame structure and the force of the conveyor belt in the weighing section,establish a mechanical model of the symmetrical belt conveyor weighing device,and derive a section The expression of the cumulative mass of the conveying belt running material within the time.The advantages and disadvantages of the electronic belt weigher with single roller type,multiple roller type and complete machine structure are analyzed from accuracy,stability,complexity and working conditions.Symmetrical type,double roller type,and suspension type structure are selected.The weighing frame can offset the horizontal influence,the structure is stable and simple,and the weighing accuracy can be improved.Analyze the influencing factors of the weighing accuracy of the symmetrical belt conveyor weighing device,which are mainly composed of tension factors,speed factors and external environmental factors.The tension factor has the greatest influence.The weighing error decreases with the increase of the initial tension of the belt conveyor,and increases with the increase of the uniform load mass of the material;the speed factor is mainly composed of the incremental rotary encoder speed measurement point and The load cell’s measuring points are inconsistent,caused by the deviation between the rolling direction of the incremental rotary encoder and the running direction of the conveyor belt;the external environmental factors mainly include temperature,humidity,electromagnetic interference and vibration,and the tension of the conveyor belt decreases with the increase of temperature.Small,the quality of the conveyor belt increases with the increase of humidity,and the comprehensive error influence of external environmental factors is less than ±0.2%.According to the hysteresis of the load cell itself,the Preisach modeling and the optimization and experimental verification of the Preisach model are carried out.The results show that the optimization of the Preisach model effectively reduces the hysteresis of the load cell,and the maximum error is reduced from 10.26% to 1.66% And as the number of loading increases,the accumulation of errors is effectively reduced.Analyze the hardware requirements of the weighing device of the symmetric belt conveyor,design and build the circuit diagram of the weighing device of the symmetric belt conveyor;optimize the access of the speed signal and the weighing signal;the conveyor belt will run the material for a period of time The cumulative mass expression is written into the PLC and SIWAREX weighing modules,and is equipped with a weighing zero adjustment function,and a timer function is used to control the accumulation sub-interval of the material weight signal;a function-rich man-machine interface is designed to perform Monitoring,control and storage of weighing results.A symmetrical belt conveyor weighing device experimental platform was built,and the control variable method and multi-factor analysis method were used to measure the belt conveyor weighing with the scale structure,initial tension,and uniform load mass as the control group.The experiment,the experimental result basically accords with the error theory analysis.The results show that using a symmetrical structure has a smaller error than a single roller structure;within a certain range,the greater the initial tension,the smaller the error;the smaller the uniform load of the material,the smaller the error,but the smaller the mass,the more vulnerable In order to improve the operation efficiency,the uniform load quality should not be too low.