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For the balance of the axial force in single-stage pumps, there are generally the following methods: creating balance holes – drilling several holes near the hub on the pump’s rear cover, and adding a seal ring to this rear cover; the outer diameter of this seal ring is equal to the outer diameter of the impeller’s inlet. When the pump is operating, the liquid inside the seal ring of the rear cover is in communication with the suction inlet, and its pressure is similar to that of the suction inlet. The area of the rear cover outside the sealing ring is equal to the area of the front cover outside the suction inlet; as a result, the total force exerted by the liquid exiting under pressure on the front and rear covers is roughly equal. The small amount of unbalanced axial force is borne by the bearings. Under normal circumstances, opening balance holes is an effective way to balance axial forces. Its characteristics are: significant leakage, and the liquid passing through the balance hole interferes with the normal flow of liquid at the impeller inlet, resulting in a reduction in the efficiency of the centrifugal pump by about 2-5%; it is only suitable for small single-stage centrifugal pumps. Use of a balance tube: This method is essentially similar to that of using balance holes. A ring is installed on the rear cover of the impeller at the location corresponding to the inlet, and a balance tube is used to introduce the liquid from this sealed space into the pump inlet, thereby balancing the hydraulic pressure in this area with the inlet pressure. This helps to balance the axial forces. For this device, it is required that the cross-sectional area through which fluid flows in the balance tube be 4–5 times greater than the cross-sectional area through which fluid flows in the gap between the rings. Use of balancing vanes: Several radial ribs are symmetrically arranged on the back side of the impeller’s rear cover. As the impeller rotates, these ribs act like pump blades, accelerating the rotation of the fluid on the back side of the blades. This increases the centrifugal force, resulting in a significant decrease in pressure on that side of the blades. As a result, pressure is balanced on both sides of the impeller. The degree of this balance depends on the size of the balancing vanes and the gap between the blades and the pump casing. The downside is a decrease in pump efficiency. Double-suction impeller: In single-stage centrifugal pumps with high flow rates, or in a few multi-stage centrifugal pumps, impellers with water inlet on both sides are used; the axial thrust is balanced by the operating conditions of such impellers. However, since it is difficult for manufacturers to ensure that the geometric shapes of the flow-through components on both sides of the pump are exactly identical, a slight axial force still acts on the rotor. This force is then absorbed by a single row of radial ball bearings located at one end of the pump shaft. Additionally, for the axial balancing devices of multi-stage pumps, methods such as symmetric arrangement of impellers, balance hubs for balancing axial forces, and balance discs for balancing axial forces can be employed.