• Rotary

Centrifugal High Speed Pump

In a single stage, single suction, high speed centrifugal pump utilizing a closed Francis-vane impeller including a radially extending vane support portion having an outer discharge diameter at least approximately twice the inlet diameter of the inlet eye of the impeller, operating noise is reduced by encasing a single-step helical gear drive arrangement in a common bearing housing with the impeller's shaft. The operating noise is further reduced by forming the driven helical gear directly on the impeller's shaft to improve dynamic balance, by tensioning the shaft to reduce its vibration, and by mounting a plurality of fins on the bearing housing of the pump to absorb some of the high frequency sound wave energy of the pump and to translate a further portion of the high frequency sound wave energy into low frequency mechanical vibrations of the fins. Additional reductions in operating noise are obtained by encasing the fins within a shroud and by providing a fan to blow ambient air by the fins to disrupt the sound wave patterns emanating from the bearing housing.

Specification Content