Study on Radial Force of a Modified Centrifugal Charging Pump

In order to reduce the leakage of an ordinary centrifugal pump used as the charging pump of a triplex drilling pump, the characteristics of the pump and the analytic formula of the leakage are analyzed, and it is held that the leakage is mainly caused by the clearance of the bearing seal of the pump, and the clearance is caused by the radial force acting on the turbine wheel of the pump. The analyses show that the radial force and the clearance of the ordinary centrifugal pump are too great, so it is not suitable to using as the charging pump. The authors designed a modified centrifugal pump, and its water pressurizing room is composed of two sections: circular section and spiral section. The radial forces of the centrifugal pumps with circular, spiral and circular spiral pressurizing water rooms separately are qualitatively analyzed, and it is shown that the radial force of the modified pump with circular spiral pressurizing water room is little, and the minimum radial force appears under little flow rate. This characteristic of the pump meets just the right requirement of a charging pump. The radial force of the pump is measured, and the measured data are compared with the calculated results of a circular pump and a volutex pump under the same specific speed. The same conclusion as the qualitative analysis above is drawn out.