The three are distinguished by their composition, manufacturing difficulty and application scope.
1. Different structures
The closed impeller is composed of blades and front and rear covers. The semi-open impeller has two structures, one is composed of a rear cover and blades, and the other is composed of a front cover and blades. The open impeller only consists of blades and blade stiffeners, without front and rear covers.
2. Different manufacturing difficulties
Due to its more complex structure, the closed impeller is more difficult to understand. Semi-open impellers are less difficult to manufacture and less expensive. The least difficult is the open impeller.
3. Different application ranges
Closed impellers are most commonly used in centrifugal pumps and are suitable for transporting clean water, solutions and other clean liquids with low viscosity that do not contain particles. The semi-open impeller has strong adaptability and has been increasingly used in centrifugal pumps for refining and chemical industries in recent years. It is suitable for transporting clean water or liquids that are close to clean water containing suspended matter such as solid particles and fibers. Open impellers are rarely used and are mainly used to transport liquids with higher viscosity and slurry liquids.
Reference: Baidu Encyclopedia-Water Pump Impeller