Abstract: A multi-stage centrifugal pump is described having a linear series of impellets mounted on a common impeller shaft, with axial thrusts imparted to the shaft by the impellets being balanced by a sealed high-pressure thrust bearing assembly secured to the pump casing. The pump is particularly suitable for using in pumping an abrasive fluid. A clean lubricating oil is supplied to the thrust bearing assembly at a pressure slightly greater than that of the abrasive pumped fluid, to ensure that the fluid that migrates across a mechanical seal interposed between the impeller assembly and the thrust bearing assembly is the lubricating oil, not the abrasive pumped fluid. High pressure differentials across a breakdown bushing involving the abrasive pumped fluid, and a resulting wear and erosion of pump components, thereby are avoided.

Abstract: A closure arrangement for a pump housing having a generally cylindrical bore, comprising a closure member connected to the housing by a closure ring and a plurality of shear studs received in threaded openings, a portion of each opening being in the housing member and a portion being in the closure ring, and locking or compression means comprising compression bolts received in the closure ring and acting on the closure member.