Centrifugal water pump impeller mainly has the following 4 types, a. closed type; b. front half open type; c. rear half open type; d. open type
1. Closed impeller: It is composed of blades, front and rear cover plates. The closed impeller has higher efficiency and is more difficult to manufacture, so it is widely used in centrifugal pumps. It is suitable for conveying clear water, solutions and other clean liquids with low viscosity and no particles.
2. Semi-open impeller: Generally, there are two structures. One is the front half-open type, which is composed of the rear cover plate and blades. The impeller efficiency of this structure is low. In order to improve the efficiency, it needs to be equipped with a seal ring with adjustable clearance. The other is The rear semi-open type is composed of front cover and blades. Since the same sealing ring as that of the closed pump impeller can be applied, the efficiency is basically the same as that of the closed impeller, and the blades also have (back blade or auxiliary impeller) in addition to conveying liquid. ) sealing effect. The semi-open impeller is suitable for transporting liquids containing suspended solids such as solid particles and fibers. The semi-open impeller is less difficult to manufacture, lower in cost, and has strong adaptability. In recent years, it has been gradually used in centrifugal pumps for refining and chemical industries, and is used to transport clean water and liquids similar to clean water.
3. Open impeller: the impeller with only blades and blade ribs, without front and rear cover plates (the number of blades of open impeller is less than 2-5 pieces). The pump impeller has low efficiency and is rarely used. It is mainly used to transport liquids with high viscosity and slurry liquids.
The impeller blades of the centrifugal pump water pump are generally backward curved blades. There are two types of blades: cylindrical and twisted. The use of twisted blades can reduce the load on the blades, improve the suction performance of the centrifugal pump, and improve the cavitation resistance, but it is difficult to manufacture and the cost is high.
Pump impeller Centrifugal pumps for oil refinery and chemical industry require the impeller to be cast or fully welded integral pump impeller. Welded water pump impellers have been developed in recent years, and are mostly used in special centrifugal pumps for chemical industries made of metal materials with poor casting performance (such as iron and its alloys). The geometric accuracy and surface finish of welded water pump impellers are than cast impellers, which is beneficial to improve the efficiency of centrifugal pumps.