The balance of the axial force of a single-stage pump generally has the following forms: 1. Open the balance hole Drill several holes on the rear cover of the pump near the hub, and add a sealing ring on the rear cover, the outer diameter of the sealing ring is equal to the outer diameter of the impeller suction inlet. When the pump is working, the liquid in the sealing ring of the back cover communicates with the suction port, and its pressure is similar to the pressure of the suction port. The area of the outer rear cover of the sealing ring is equal to the area of the outer front cover of the suction port, so the total force of the pressure of the discharged liquid on the front and rear cover is basically equal, and a small part of the unbalanced axial force is borne by the bearing. In general, the effect of opening the balance hole to balance the axial force is better. Its characteristics are: there is a lot of leakage, and the liquid passing through the balance hole interferes with the normal flow of the impeller inlet liquid, reducing the efficiency of the centrifugal pump by about 2-5%. It is only suitable for small single-stage centrifugal pumps. 2. Using balance tube This method is basically the same as the method of opening the balance hole. An orifice ring is arranged on the rear cover plate of the impeller corresponding to the suction port, and the liquid in the sealed space is introduced into the pump inlet by using the balance pipe, so that the hydraulic pressure of this part is consistent with the inlet pressure. Balance, so that the axial force is balanced. This device requires that the flow cross-sectional area of the balance pipe should be equal to or greater than 4-5 times the flow area of the mouth ring gap. 3. Using balanced blades Several radial ribs are arranged symmetrically on the back of the impeller rear cover. When the impeller rotates, the ribs, like pump blades, make the liquid on the back of the blade rotate faster, and the centrifugal force increases, which makes the pressure on the back of the blade drop significantly, so that the impeller The pressure on both sides is balanced, and the balance depends on the size of the balance vane and the gap between the vane and the pump body. The disadvantage is reduced pump efficiency. 4. Adopt double suction impeller If the impeller with double-sided water inlet is used on a single-stage centrifugal pump with a large flow rate or a small number of multi-stage centrifugal pumps, the axial thrust will be balanced by its own working conditions, but in fact it is difficult for the manufacturer to achieve the two-sided impeller of the pump. The geometric shape of the side flow parts is exactly the same, so there will still be a small axial force acting on the rotor, so it is borne by the single row radial ball bearing at one end of the pump shaft. In addition, for the multi-stage pump axial balance device, the impeller symmetrical arrangement method, the balance hub balance axial force and the balance disc balance axial force can be used.    

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