There are many ways to balance axial thrust. Generally, single-stage pumps are different from multi-stage pumps. For single-stage pumps, there are mainly three ways to balance the axial thrust: 1, balance hole; 2, balance pipe; 3, double suction impeller. The purpose of the first two methods is to make the pressure behind the impeller equal to the pressure in front of the impeller so as to balance the axial thrust. In order to reduce the pressure behind the impeller, impeller rear cover is also provided with a seal ring, the diameter of the front cover seal ring diameter equal. The latter method is to balance itself. Even so, single-stage pump is not one hundred percent balance, so the use of thrust bearings. For multi-stage pumps, there are two main balancing methods: 1, impeller symmetrical layout, 2, the use of balance plate. Method 1 is the two sets of impeller water opposite mounted on the shaft, the axial thrust offset each other. Symmetrically arranged multistage pumps are mostly volute pumps, in order to lead the water from the previous stage to another stage, the pump casing is provided with a catheter. Method 2 is used on a segmented multistage pump. Balance plate role is: the pressure from the last stage impeller out of water, through the adjustment sleeve radial gap into the balance before the water chamber, the water chamber at high pressure. Equilibrium plate after a balanced pipe connected to the pump inlet, the pressure is similar to the inlet pressure. This balance disc pressure on both sides are not equal, which also resulted in a backward axial thrust - that is, balance. The impeller axial thrust is automatically balanced. When the axial thrust of the impeller is greater than the balancing force on the balance disc, the pump rotor will move toward the inlet side and, due to inertia, this movement does not immediately stop at the equilibrium position but beyond the limit Reduce the amount of leakage to reduce the amount of leakage, increase the pressure in the water chamber, so the balancing force on the balance plate increases, and beyond the thrust of the impeller thrust the rotor to the outlet side. The same process is inertia, so that balance disc axial gap increases too much, causing the balance force is less than the axial thrust, the rotor moves to the entrance side again, repeat the above process. This process is automatic, and when the pump is in operation, the rotor is always axially displaced in some equilibrium position. However, the amount of movement is minimal, from the appearance is difficult to see. Balance disc diameter D 'and impeller seal diameter Dw size, the general is: D' = 1.05Dw