http://www.pumpdelin.com/pump-parts/ The open impeller has no cover plate on both sides of the blade, which is easy to manufacture and easy to clean. It is suitable for conveying materials containing a large amount of suspended solids, with low efficiency and low liquid pressure. The semi closed impeller has no cover plate on one side of the suction port, while there is a cover plate on the other side, which is suitable for conveying materials that are easy to precipitate or contain particles, and the efficiency is also low; the closed impeller has a front cover on both sides of the blade Rear cover plate, high efficiency, suitable for conveying clean liquid without impurity. General centrifugal pump impeller for this kind of. Main parts of centrifugal pump The main components are impeller, pump shell and shaft seal device. Impeller The function of impeller is to transfer mechanical energy of prime mover to liquid directly, so as to increase static pressure energy and kinetic energy of liquid (mainly static pressure energy). The impeller generally has 6 ~ 12 backward curved blades. Impeller has open, semi closed and closed three types. The impeller has two suction modes: single suction and double suction. Pump housing The function is to seal the impeller in a certain space, so as to inhale and press out the liquid by the impeller. Pump case made of volute shape, it is also known as volute. As the cross-sectional area of the flow channel is gradually enlarged, the high-speed liquid thrown out from the impeller gradually reduces the flow velocity, so that part of the kinetic energy can be effectively converted into static pressure energy. The pump shell not only collects the liquid thrown out by the impeller, but also is an energy conversion device. Shaft sealing device The function is to prevent the liquid in the pump shell from leaking out along the shaft or the external air leaking into the pump shell. There are two kinds of common shaft seal devices: packing seal and mechanical seal. The filler is usually impregnated with oil or coated with graphite asbestos rope. Mechanical seal mainly relies on the relative movement of the end face between the moving ring installed on the shaft and the stationary ring fixed on the pump shell to achieve the purpose of sealing.China Pump Parts website:http://www.pumpdelin.com/pump-parts/