Cavitation And Recirculation Troubleshooting Methodology

Abstract

High reliability and large rangeability are required of pumps in existing and new plants which must be capable of reliable on-off cycling operations and especially low load duties. The reliability and rangeability target is a new task for the pump designer/researcher and is made more challenging by cavitation and/or suction recirculation effects, primarily, the pump damage. Knowledge about design critical parameters and t heir optimization, and field problems diagnosis and troubleshooting has advanced considerably in recent years. The objective of the pump manufacturer is to develop design solutions, and troubleshooting approaches that improve the impeller life as related to cavitation erosion, and to enlarge the reliable operating range by minimizing the effects of the suction recirculation. A short description of several failure modes, including damage patterns and other symptoms, which are related to cavitation and/or suction recirculation is presented. The troubleshooting methodology is described in detail, focusing on the various steps of failure analysis diagnosis, and solution strategy, including quick fixes and ultimate solutions along with new material. The troubleshooting method essentially is focused on failures characterized by metal damage.