There are four types of impeller: runner type (single runner, double runner), vane type (closed, open), spiral centrifugal type and swirl type. The performance and structure of various impellers are detailed as follows. Centrifugal pump impeller is generally closed impeller.
Runner impeller is a curved runner from the inlet to the outlet. This type of impeller is suitable for conveying liquids containing large particles of impurities or long fibers. Because this type of impeller has excellent anti clogging performance. Its disadvantage is that its anti cavitation performance is weaker than other forms.
The semi open impeller and open impeller in the vane impeller are easy to cast, and easy to maintain and clean up the impurities blocked in the transportation process. But its disadvantage is that the gap between the wall and the blade of the pressurized water chamber is increased due to the erosion of solid particles during the transportation process, which reduces the operation efficiency of the water pump. Because of the increase of the gap, the stability of the flow state of the liquid in the flow passage is damaged and the pump vibrates. This type of impeller is not easy to transport medium containing large particles and long fibers. The closed impeller has the advantages of high efficiency, stable operation for a long time and small axial thrust of the pump, but the closed impeller is easy to be wound, and it is not easy to transport sewage medium containing large particles or long fibers.
Spiral centrifugal impeller
The spiral centrifugal impeller is a twisted blade, which extends axially from the suction port on the conical hub. The delivered liquid will not impact any part of the pump when passing through the blades, so there is no damage to the pump and no damage to the delivered liquid. Because of the propelling effect of the screw and the strong passing ability of the suspended particles, the pump with this type of impeller is suitable for pumping the medium containing large particles and long fibers.
The swirl impeller is a kind of impeller that is all or part of the impeller is shrunk to the flow passage of the water chamber, which has good anti clogging performance. The particles flow in the water pressure chamber is driven by the vortex generated by the rotation of the impeller. The motion of the suspended particles does not generate energy itself, and the energy is exchanged with the liquid in the flow passage. In the flow process, the suspended particles or long fibers do not contact with the worn blade, the wear condition is lighter, and there is no increase of the gap due to wear, so it is suitable for pumping medium containing large particles and long fibers.