Centrifuge is now widely use and the main working principle of centrifugal pump is using the centrifuge to work.
Firstly, the impeller is rotating by driving the pump shaft, doing work on the blade between the fluids by the centrifugal effect, and thrown to outside from the centre of the impeller. The speed is too high when the fluid reaches to the outside of the impeller.
Secondly, the liquid thrown from the blade is collected by the pump shell, and the liquid in the shell follow to the expansive direction by the shell channel, which makes the fluid kinetic energy is converted to static pressure and reduce the loss of the energy. So the function of the pump shell is not only collected liquid, but also an energy conversion device.
Thirdly, the principle of absorbing the liquid suction with a high-speed rotating impeller, which forces the liquid in the center, be discarded at a high-speed of the impeller, in order to form a low pressure in the center of the impeller, and absorb the liquid continuously from the low tough. If a centrifugal pump is full of gas before starting, a large enough vacuum formation cannot be formed when the gas is thrown down in the center after starting the impeller, so that liquid cannot be sucked in the tank, such a kind of phenomenon is called air bounding.
In order to prevent the phenomenon of air bounding happened, it must be filled with liquid before starting the centrifugal pump, this step called irrigation pump operation. And to stop the liquid injection pump shell follow into the low slot by gravity, should equip with check valve at the entrance of the pump suction line. If the position of the pump is lower than the liquid surface of the slot, without irrigation pump when it starts.
Fourthly, install guide roller around the impeller, which makes high energy conversion efficiency of the liquid in the centrifugal pump. Roller is a ring with a leaf in peripheral impeller. The bending direction of the blade is opposite to the bending direction of the impeller, its bending angle is corresponding to the direction of the liquid flow from the impeller, which guide liquid change its direction smoothly in the pump shell, make the loss of energy reduce to the bottom out and improve the efficiency of dynamic pressure to be converted to static pressure.
Fifthly, the balance hole of the back shroud eliminates axial thrust. The liquid pressure which has left the peripheral impeller is high, some osmoses to the behind of the back shroud, and the low pressure is formed at the liquid entrance of the side of the impeller, which creates thrust to push pump impeller inlet side of the axial thrust. This will be easy to cause loss of it, if it is seriously, vibration can be produced. The pressure difference in front of and behind the impeller will be reduced if the balance hole makes some of high-pressure liquid leak to the low pressure area, but this may cause low centrifugal pump efficiency.