What Is The Working Principle And Structure Of Submerged Pump Impeller

May 04, 2022

The impeller is composed of hub, blade and cover plate. The cover plate of the submerged pump impeller is divided into the front cover plate and the rear cover plate. The cover plate on the inlet side of the impeller is called the front cover plate and the cover plate on the other side is called the rear cover plate.

According to the impeller form, it can be divided into the following three types:

Closed impeller: There are cover plates on both sides of the submerged pump impeller and there are 4-6 blades between the cover plates. When the bending direction of the blade is opposite to the rotation direction of the submerged pump, it is called the backward bending blade. Generally, the blades of the impeller are backward curved blades. This submerged pump closed impeller has high efficiency and is the most used. It is suitable for pumping clean liquid without solid particles and fibers. The closed impeller of the submerged pump has two types: single suction and double suction. The flow of the double suction impeller is larger than that of the single suction impeller.

Open impeller: There is no cover plate on both sides of the impeller, and the blades are connected through shaft holes. The impeller has the advantages of a simple structure, easy manufacture, but low efficiency. It is suitable for conveying liquids containing more solid suspended solids or fibers.

Semi-open impeller: This kind of impeller has only a rear cover plate. It can pump the liquid that is easy to precipitate or contains solid suspended solids. The efficiency is between the open impeller and the closed impeller of the submerged pump.

According to the shape of the impeller and the flow direction of the liquid in the pump shell, the impeller of the submerged pump can be divided into runoff type, mixed flow type and axial flow type.

The runoff submerged pump is basically a centrifugal pump. The liquid enters the impeller along the axial direction and is thrown out along the radial direction. The kinetic energy obtained by the liquid mainly comes from the centrifugal force generated when the impeller of the submerged pump rotates.

The liquid in the impeller of mixed flow submerged pump enters the impeller along the axial direction and flows out along the oblique direction between the axial direction and the radial direction. The kinetic energy of the liquid is generated by the mixing action of centrifugal force and axial thrust. The impeller of the underwater axial flow pump makes the liquid flow axially and the energy obtained by the liquid is mainly the thrust generated by the rotation of the impeller.

According to the needs of application, the impeller can be made of cast iron, cast steel, stainless steel, FRP, plastic and other materials. The processing methods of the impeller of the submerged pump include sand casting, precision casting, welding, molding, etc. The size, shape and manufacturing accuracy of the impeller have a great impact on the performance of the submerged pump.