为便于说明问题,先将清筛机上采用的二层筛网作一简要分析(见图1)。设Q总为挖掘输送来的石碴总量。就普通振动筛而言,当Q总进入上层筛网时,Q总将按照筛孔大小,分别流向。粒度大于筛孔的Q_1,经筛面流入线路;粒度小于筛孔的Q_2,进入下层筛网。Q_2又按下层筛孔大小,分为Q_3及Q_4,其中Q_3经筛面与Q_1汇合流入线路; In order to explain the problem, the first screen on the sieve used in a simple analysis (see Figure 1). Let Q always tap the total amount of ballast delivered. In the case of ordinary shale shakers, when Q always enters the upper sieve, Q always flows in accordance with the size of the sieve. The particle size is greater than the mesh Q_1, the screen surface into the line; particle size smaller than the mesh Q_2, into the lower screen. Q_2 again according to the size of the lower sieve, divided into Q_3 and Q_4, which Q_3 by the screen surface and Q_1 convergence into the line;