The impeller is assembled on the pump body and can be divided into three types: open impeller, semi-open impeller and closed impeller. The best process for investment casting impellers is silica sol casting because of its high precision. The following is a brief introduction of various investment casting impellers:
Investment casting open impeller
The impeller only has blades and blade stiffeners, without front and rear covers. Due to low efficiency, it is less used. Mainly used for conveying high viscosity liquids and slurries.
Precision casting semi-open impeller
There are generally two structures. One is the front semi-open impeller, which consists of a rear cover plate and blades. The impeller efficiency of this structure is low, in order to improve the efficiency, an adjustable gap sealing ring should be installed. The other is the rear semi-open impeller, which consists of a front cover plate and blades. Efficiency is almost the same as a hermetic impeller, since the same sealing ring as a hermetic impeller can be used. The vanes also have a sealing function for conveying liquids. The semi-open impeller is suitable for conveying liquids containing suspended solids such as solid particles and fibers. Due to its low manufacturing difficulty, low cost and strong adaptability, its application in refining and chemical centrifugal pumps has become a trend, and it is also used to transport water and liquids similar to water.
Precision casting enclosed impeller
It consists of impeller blades and front and rear cover plates. The closed impeller has high efficiency, but is difficult to manufacture, and is mostly used in centrifugal pumps. The enclosed impeller is suitable for conveying clean fluids with low viscosity such as clean water, solutions without any particles.