计算筛分效率时需要确定筛上物与筛下物的分级粒度界限，即分级粒度．分级粒度不同的划定原则使得与之时应的筛分效率具有不同的意义。在实际筛分作业中应使依照不同原则划定的分级粒度要尽可能地接近直至相等，这样就可以通过对筛机的作业参数进行简单的调整而收到显著的经济效益。 When calculating the screening efficiency, it is necessary to determine the classification granularity limit of the sieve substance and the sieve substance, that is, the classification granularity. The principle of delineation of different grading granularity makes the screening efficiency with different meaning have different meanings. In the actual screening operation should be based on different principles delineated grading size should be as close as possible until equal, so that you can get a significant economic benefit by simply adjusting the operating parameters of the sieve machine.