Balance hole can not be too much open, mainly affecting the efficiency of the pump, the following describes some of the axial thrust of the pump balance. For the single-stage pump axial force balance generally have the following forms: 1, open the balance hole in the pump near the rear cover plate drilling a few holes, and in the rear cover to add a ring, the ring outside Diameter and impeller inlet diameter equal. Pump work, the back cover ring liquid and suction port connected, the pressure and suction port pressure is similar. Seal outside the cover area and the suction port outside the front cover of the same area, thus sending the liquid pressure in the front and rear cover of the total force is basically equal to a small part of the unbalanced axial force by the bearing. Under normal circumstances, a balanced hole balancing axial force better. Its characteristics are: more leakage, through the balanced hole of the liquid and impede the normal flow of impeller liquid inlet, the centrifugal pump to reduce the efficiency of about 2-5%, only for small single-stage centrifugal pump. 2, the use of this method of balance pipe and open the hole method is basically the same, in the impeller rear cover and the suction port corresponding to set mouth ring, the use of balance pipe to the liquid in this sealed space into the pump inlet, so that Part of the hydraulic pressure balance with the inlet, so that the axial force balance, this device requires cross-flow pipe cross-sectional area should be equal to or greater than the mouth ring gap flow area 4-5 times. 3, the use of balanced blades on the back of the impeller rear cover symmetrically placed a few radial ribs, when the impeller rotation, the same as the pump blades to make the blade back of the liquid to accelerate the rotation, increased centrifugal force, so that the back of the blade pressure significantly Drop, so that the pressure on both sides of the impeller balance, the balance depends on the balance of the size of the blade and the gap between the blade and the pump body. The disadvantage is the pump efficiency is reduced. 4, the use of double-suction impeller in the larger flow single-stage centrifugal pump or a few multistage centrifugal pump with double inlet impeller, the axial thrust by its own working conditions to be balanced, but in fact the manufacturer is very It is difficult to achieve exactly the same geometry of the overcurrent components on both sides of the pump so that there will still be less axial forces acting on the rotor and therefore being supported by single row radial ball bearings on one end of the pump shaft. In addition, for multi-stage pump axial balance device, impeller symmetrical layout method, balanced hub balance axial force and balancing disk balance axial force and other forms.
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