Design of bladeless impellers for abrasive fluid pumping

Abstract

Centrifugal pumps are commonly used by mineral processing companies, such as Vale, CBMM, Kinross, and Anglo-American. As a consequence of the presence of abrasive particles in the mineral pulp, their housing and impellers readily wear out. As a result, industrial companies invest a lot of their financial resources in the maintenance of these pumps, in addition to replacing their damaged mechanical parts. To solve this problem, some researchers have been proposing novel metal alloys to improve centrifugal pump properties and mechanical endurance. In an attempt to explore a new approach, this study focuses on the disc impellers reported in Nikola Tesla’s patents. In the laboratory, an experimental bench was developed to simulate the pumping of a highly abrasive pulp composed of water and silicon carbide. An impeller base was designed to allow the assembly of 2, 3 and 4 discs. It was observed that an increase in the number of discs resulted in increased pump performance. However, the dimensions and distance between the discs depend on operational parameters, such as: dimensions of the housing and the abrasive particles to be pumped. Besides, disc impellers need to operate at higher rotations to reach the same flow and total head obtained from commercial blade impellers. In this work, the wear on the casing and on the three-disc and semi-open impellers was quantified by measuring mass losses. The disc impellers showed less wear, which provides an increase in their useful life. In addition, a three-disc impeller demonstrated high performance when compared to a semi-open impeller.