Main working principle:

(1) The impeller is driven by the pump shaft to rotate, the fluid located between the blades to do work, the fluid by centrifugal effect, by the impeller centre is thrown to the periphery. When the fluid reaches the periphery of the impeller, the flow rate is very high.

(2) The pump casing collects the liquid thrown out from between the blades, and these fluids flow in the casing in the direction of gradually expanding the worm shell-shaped channel, so that the kinetic energy of the fluid is converted into static pressure energy, reducing energy loss. So the role of the pump casing is not only in the collection of liquid, it is an energy conversion device.

(3) Liquid suction principle: rely on the impeller high-speed rotation, forcing the impeller centre of the liquid at a high speed to be thrown away, thus forming a low pressure in the centre of the impeller, and the liquid in the low slot is therefore continuously sucked up.

Gas bondage phenomenon: If the centrifugal pump is filled with gas in the shell before starting, the impeller centre gas can not be thrown after starting the formation of a sufficiently large vacuum in the place, so that the liquid in the tank can not be sucked on. This phenomenon is called air binding.

In order to prevent the occurrence of gas binding phenomenon, centrifugal pump start before the pump casing with foreign liquid to fill the space. This step is called filling the pump. In order to prevent the liquid in the pump casing from flowing into the low slot due to gravity, the inlet of the pump suction line is equipped with a non-return valve (bottom valve); if the pump position is lower than the liquid level in the slot, there is no need to fill the pump when starting.

(4) The guide wheel is installed at the periphery of the impeller, which makes the energy conversion efficiency of the liquid in the pump high. The guide wheel is a fixed ring with blades located on the periphery of the impeller. The bending direction of these blades is opposite to that of the impeller blades, and the bending angle is exactly in line with the direction of liquid outflow from the impeller, which guides the liquid to change direction smoothly in the pump casing channel and minimises energy loss, and the efficiency of converting the dynamic pressure energy into the static pressure energy is high.

(5) The balance hole on the back cover plate eliminates axial thrust. Leaving the impeller periphery of the liquid pressure has been higher, a part of the impeller will seep into the impeller after the cover plate back side, while the impeller front side of the liquid inlet is low pressure, thus generating the impeller pushed to the pump inlet side of the axial thrust. This is likely to cause wear at the contact between the impeller and the pump casing, and in severe cases, vibration will also be generated. Balance hole so that part of the high-pressure liquid leakage to the low-pressure area, to reduce the pressure difference between the impeller before and after. But this will also cause a reduction in pump efficiency.

(6) shaft sealing device to ensure that the centrifugal pump normal, efficient operation. Centrifugal pump in the work is the pump shaft rotation and the shell does not move, the ring gap between them if not sealed or sealed bad, the outside air will penetrate into the impeller centre of the low-pressure area, so that the pump flow, efficiency decline. In severe cases, the flow rate is zero - air binding. Usually, mechanical seal or packing seal can be used to achieve the seal between the shaft and the shell.