According to the shape of screening impurities to shoose hole-shaped sieve plate (move out long ,Diamond impurities)and the slit-shaped sieve plate (move out particles shape impurities and emplastic).

根据筛选杂质的形状特点可以选择孔形筛板（去长、菱形杂质）和缝形筛板（去颗粒形杂质和粘胶物）。