种子清选机电磁变频激振清筛装置设计与试验

Design and Test of Electromagnetic Variable Frequency Excitation Sieve-cleaning Device of Seed Cleaner

清筛装置对筛片的振动激励是提高物料透筛概率、减少筛孔堵塞以及有效清筛的根本因素。现有清筛装置多使用随机弹跳的橡胶球完成清筛作业,但其清筛效果易受到结构与工作参数制约。为解决橡胶球激振力难以精准调控问题,设计了电磁变频激振清筛装置,阐述了总体结构与工作原理,设计了激振清筛单体与变频激振控制系统,分析了振动激励作用机制;以加速度为指标,研究了弹簧预压缩量与激振频率对振动激励的影响规律,结果表明两者均与振动激励正相关;以净度、筛分效率、筛分时间、卡种数量为指标开展了16组玉米种子清选试验,试验结果表明弹簧预压缩量为2 mm、工作频率为3.5 Hz、清筛频率为50 Hz时清筛装置具有较好的作业效果,种子净度99.1%,筛分效率88.6%,筛分时间70 s,卡种数量为0;通过分段设置工作频率与清筛频率,实现了清筛装置激振力的精准调控,能够满足不同工况下正常筛分与强振清筛的作业要求。

The vibratory excitation of the sieve by the sieve-cleaning device is a fundamental reason for increasing the probability of material penetration,reducing seed clogging and effective sieve cleaning.Existing sieve-cleaning devices mostly use randomly bouncing rubber balls to clean the sieve,but the sieve-cleaning effect is easily restricted by the structure and operating parameters.In order to solve the problem that rubber balls’impact force is difficult to accurately control,an electromagnetic variable frequency excitation sieve-cleaning device was developed,the overall structure and operating principle was introduced,the excitation sieve-cleaning monomer and frequency conversion excitation control system was designed,and the vibration excitation mechanism was analysed;using acceleration as an indicator,the effects of spring pre-compression and excitation frequency on the vibration excitation law were studied,the results showed that both were positively related to the vibration excitation;sixteen sets of maize seed cleaning trials were carried out by using purity,screening efficiency,screening time and number of clogging seeds as indicators.The results showed that the sieve-cleaning device had a good operating effect when the spring pre-compression was 2mm,the operating frequency was 3.5Hz and the sieve cleaning frequency was 50Hz,with seed purity of 99.1%,screening efficiency of 88.6%,screening time of 70s,and clogging seed of 0.By setting the operating frequency and the sieve cleaning frequency in stages,the sieve-cleaning device could be precisely adjusted to meet the requirements of normal sieving and strong vibration sieve cleaning under different operating conditions.The research could provide reference for the development of intelligent sieve-cleaning equipment.