The Development of PTFE Faced Hydrodynamic Thrust Bearings for Hydrogenerator Application in the UK

Abstract

Polytctrafluorocthylenc (PTFE)-faced hydrodynamic thrust bearings have been used for many years in the fonner Soviet Union and in the People’s Republic of China for large hydrogenerator applications. Although there has been some recent interest in other countries, few installations of this sort have previously been reported in Europe or the USA. This paper describes the state of the art and the development and laboratory testing of a prototype set of PTFE pads. Following these trials, a second larger set of thrust pads was designed for use in the pumped-storage hydroelectric power station at Ffestiniog in North Wales. The pads were installed in September 1996 and inspected in May 1997. After nearly 3000 h of operation including 900 separate occasions when the system was started up under load, the pads were found to be in excellent condition. Further hydrogenerator installations of PTFE-faced pads are planned as a result of this successful development.

Introduction

Polytetrafluoroethylene (PTFE)-faced bearings have been widely used for heavy-duty thrust bearing applications for many years in Eastern Europe and the People’s Republic of China but hitherto have had little exposure in other parts of the world. The purpose of this paper is twofold: to summarize the state of the art so far as it can be discerned from the available literature and to report on the design and testing of PTFE-faced thrust pads, first for laboratory experiments and then for a major UK generating facility.