Experimental Study On The Effect Of Different Motion Forms Of Vibrating Screen On Maize Particles Dispersion

Vibrating screen is an important part of maize combine,which directly affects the performance of maize combine.In the operation of vibrating screen,the dispersion degree of particle group on the screen surface of vibrating screen directly affects the dispersion and permeability of materials,and then affects the screening efficiency of vibrating screen.At present,the research on the dispersion of particle groups on the screen surface of different vibrating screens is mainly based on simulation re search,while the research on the dispersion of particle groups on different screen surface is rarely reported,and the role of airflow is ignored.Under the condition of the same initial airflow,the movement as a result of the vibrating screen and vibrating screen space on the screen flow distribution,the flow effect of particles,in view of regulating fan flow through bench test is also difficult to implement different vibrating screen oversize airflow field distribution are the same.Relying on the National Natural Science Foundation of China(51475090),Heilongjiang Science Foundation(E2017004),the National Key Research and Development Program(2018YFD0300103)and the Key Laboratory of Heilongjiang Province for Modern Agricultural Equipment in Northern Cold Areas.we consider the movement of the vibrating screen form of particle group and to examine the effects of dispersion.The research in this paper mainly includes election of vibrating screen mechanism,three kinds of vibration screen motion form analysis,three kinds of vibration screen particle nonlinear runout theory analysis,particle group dispersion test on vibration plate,material screening test and other contents.The research content and conclusions of this paper are as follows:Based on the research platform of three vibrating screens,the composition and working principle of three kinds of vibrating screen mechanisms are expounded.The screen surface of the planar reciprocating vibrating screen moves along the x and y directions driven by the driving mechanism.The screen surface of the three-moving and one-swinging vibrating screen realizes the movement along the x,y and z directions and the swing along the z direction under the drive mechanism.The screen surface of the three-moving two-rotating sieve is driven by the driving mechanism to move along the x,y and z directions and swing along the x and z directions.According to the driving mechanism of three kinds of vibrating screen,the two-dimensional mapping of the vibrating screen is obtained,and the eigenvalue of the jacobian matrix of the two-dimensional mapping is further obtained.Based on Matlab numerical calculation and visualization functions,the characteristic values of fixed point mapping of the three kinds of vibrating screens were numerically simulated,and the movement rules of particles along the length direction of the screen surface on the plane reciprocating vibrating screen,three translations and one swing vibrating screen and three translations and two swing vibrating screen were obtained.The coordinates of the particles at different moments on the three vibr ating plates were extracted by using the high-speed camera post-processing software,and the displacement of the particles along the x,y and z directions of the screen surface was obtained.The results show that the displacement of particles in the x and z directions on the vibrating plate increases gradually with time,indicating that the dispersion of particle groups on the plate increases gradually,which is conducive to the dispersion of particles along the x and z directions of the plate.The dispersion degree of particle groups at different spindle speeds of three vibrating screens was obtained according to the calculation formula of dispersion index.The corresponding spindle speed of the optimal dispersion degree of particle groups on three vibrating plates was determined.The optimal spindle speed corresponding to the optimal dispersion of the particle group in the plane reciprocating,three-moving,one swinging and three-moving vibration plates is 240 r/min,250 r/min and 240 r/min,respectively.Under the optimal rotation speed of the main shaft of the vibrating screen,the comprehensive dispersion of the particle group on the plane reciprocating vibration plate was 34.06,and that of the corn particle group on the three moving one swinging and thre e moving two rotating vibration plate was 38.96 and 40.73,respectively.This indicates that the rotation along the x direction has a significant effect on the dispersion of the particle group.The sieving test of corn exudate on three vibrating screens wa s carried out,and the dispersion and sieving efficiency were used as the test indexes to track the dispersion of corn particle group in real time.The relationship between dispersion and screening efficiency was obtained.When the feeding amount of corn ejectors is 5 kg/s,the screening performance of the three kinds of vibrating screens is in order from high to low: three translations and two swing vibrating screens,three translations and one swing vibrating screens,and planar reciprocating vibrating sc reens.This study proved the feasibility of using plate to study the dispersion of particle group and the accuracy of the results of plate test,and provided a reference for the selection of different shakers and the design and application of new shakers.