semiclausum impeller intake at the side of non-cover plate, while at the other side there is cover for easy transport or precipitation particles containing materials, the efficiency is lower;

• 半闭式叶轮在吸入口一侧无盖板，而在另一侧有盖板，适用于输送易沉淀或含有颗粒的物料，效率也较低；