INTEGRATED PRESSURIZED PUMP SHAFT SEAL ASSEMBLY AND METHOD OF USE THEREOF

An integrated pressurized pump shaft seal assembly for a submersible rotary fluid pump comprises an oil reservoir having a pressure equal or less than the ambient pressure external fluids surrounding the casing, the oil reservoir feeding an oil pump impeller that is mountable onto, so as to be rotated by, the rotary fluid pump shaft. The impeller is a radial hole impeller in fluid communication with an adjacent diffusion element comprising an internal diffusion bore in fluid communication with an axially vertical spiral volute diffusion chamber located between inner and outer walls of a mechanical seal housing. The centrifugal oil pump impeller pumps oil from the oil reservoir to the seal chamber through the diffusion element and the internal volute diffusion element so as to increase a pressure within the seal chamber to a positive pressure above the ambient pressure of the external fluids surrounding the pump housing.