Pump shaft failures - a compendium of case studies

Abstract

During operation, pump shafts usually suffer from degradation as a result of corrosion and/or mechanical degradation, usually in the form of fatigue failures. In many cases corrosion precedes fatigue failure and can actually accelerate the rate of failure. Pump shafts are generally exposed to the liquid being pumped either on a continual basis or at certain locations along the length of the shaft. Specialised sealing arrangements comprising sleeves and o-rings can be used to reduce the amount of liquid ingress, however, where these sealing systems are not implemented or where the integrity of these seals is compromised, damage to the shaft in the form of corrosion may occur. This paper presents a collection of pump shaft failures that have been encountered during the consulting activities at the University of the Witwatersrand and the Plant Infrastructure and Pipelines Centre at the Council for Scientific and Industrial Research (CSIR).