New method for axial force balance of canned motor pump

The magnitude of axial force has great impacts on the life and efficiency of canned motor pump. Because the traditional balance methods can not completely eliminate the axial force of canned motor pump, it is quite necessary to create new technique. Based on the analysis and calculation of axial force of canned motor pump, an auxiliary impeller was designed using the method of examination calculation. The auxiliary impeller drives coolant in the cooling circuit, and generates an axial force which is equal and opposite to axial force by the main impeller and rotor gravity force, thereby the axial force was eliminated. Through the axial force comparisons between theory calculation and experimental measurement, the residual axial force of canned motor pump is small, and the calculation results are basically consistent with experimental measurements. The practical application indicates that the new axial force balance method of canned motor pump is reliable and the calculation is correct. The new method can basically eliminate the residual axial force, reduce the bearing load and extend bearing life, so the canned motor pump can run safely and reliably. These research achievements are also valuable for engineering application.