The semi-open impeller and open impeller in the vane impeller are easy to cast, and easy to maintain and clean the impurities blocked in the transportation process. However, its disadvantage is that the gap between the wall of the pressurized water chamber and the blade increases under the abrasion of solid particles during the transportation process, which reduces the operation efficiency of the pump, and because the increase of the gap destroys the stability of the flow pattern of the liquid in the flow channel, causing the pump to vibrate. This type of impeller is not easy to transport the medium containing large particles and long fibers.