Abstract: An improved system for mounting components to a rotatable shaft. The improved system may include a pump having impellers keyed to a rotatable shaft. Diffusers cooperate with the impellers to conduct pumped fluid upward from the impeller. The improved system for mounting includes a plurality of stop rings and an expansion assembly. A stop ring is secured to the shaft at each end of the rotatable component. An expansion assembly is disposed between a first stop ring and the rotatable component. The expansion assembly is axially expanded to force the rotatable component against a second stop ring.

Abstract: A centrifugal liquid-gas separator apparatus which is particularly adapted for use downhole with a submergible pump comprises an elongated hub having disposed on its periphery helical blades defining a screw-type inducer for pressurizing a liquid-gas fluid mixture entering the apparatus, axially extending vanes defining a centrifugal separator for separating the liquid and gas components of the fluid mixture, and smoothly curved blade segments disposed intermediate the blades and the vanes for providing a smooth transition for the fluid mixture flowing from the inducer to the centrifugal separator. The apparatus is capable of maintaining a substantially constant flow rate over a large range of volumetric ratios of gas to liquid.