Influence of Submerged Bearings for Vertical Pumps on Vibration Characteristics

Abstract

As long as each component part of pumps is produced within their fixed limit, and pumps are set with reasonable accuracy, it is generally considered that the bearing load generated by rotating shafts is small in vertical pumps. However, even though pumps are operated under the same conditions, the life times of bearings often makes a difference among the kinds of them related to their structure and / or materials, and problems with vibration are frequently experienced. Therefore, using an apparatus that is similar to a real pump, the influence of three kinds of bearings made of synthetic rubber (NBR), polytetrafluoroethylene (PTFE) and ceramics (SiC) on the vibration characteristics of the pump was investigated. As a result, an anomalous phenmenon of self-excited vibration was observed when ceramics bearings were used.