Pitot pump with jet pump operated thrust balance

Abstract

This pitot pump is provided with pressure balancing for minimizing thrust loads on its bearings. The pump has a housing containing a rotatable casing mounted on a shaft. A fixed pitot tube is mounted in the casing for withdrawing pressurized fluid as the casing rotates and discharging the fluid through an axial outlet passage extending through one end wall of the casing. Fluid is introduced to the casing through the same end wall by way of an annular inlet passage coaxial with the outlet passage. The fluid flows from this inlet passage to the interior of the casing through a plurality of radiating passages in the end wall of the casing. When such a pump is used with a pressurized inlet fluid, an axial thrust on the casing bearings would result if it were not for the thrust balancing means. This comprises an axial balancing chamber between a portion of the end wall opposite the fluid inlet and a portion of the pitot tube. The interior of this chamber is in fluid communication with the suction inlet of a jet pump. Pressurized fluid from the pitot pump is applied to the jet inlet of the jet pump and the outlet of the jet pump is connected to the inlet to the pitot pump. Thus, pressure in the balancing chamber is reduced for minimizing axial thrust and any fluid entering the chamber from the interior of the casing is repressurized and returned to the pitot pump inlet.