Centrifugal pitot pump with means for improving net positive suction head

摘要

A centrifugal pitot pump has a rotor driven in rotation within a casing. A pitot tube pickup in a rotor chamber within the rotor intercepts rotating fluid and withdraws the fluid through a duct. The duct mounts the pitot tube and passes through the rotor casing. Fluid to be pumped passes through the annulus between the rotor and the duct and up through generally radial passages in the rotor into the rotor chamber. A leakage path from the rotor chamber to the inlet annulus between a hub of the pitot tube pickup and the rotor permits fluid to pass from the chamber into the annulus. A ring interrupts line-of-sight communication between the chamber and the annulus along the leak path and dissipates considerable of the leaking fluid velocity head to thereby improve the net positive suction head of the pump. The entrances of the radial passages in the rotor are large in the axial direction to reduce the sharpness of the turn from the annulus into these passages, to thereby reduce the net positive suction head required to operate the pump without cavitation.