Design of a New Tribometer for Tribological and Viscoelasticity Studies of PTFE Valve Seats

This paper presents a new tribometer developed for a study of the tribological and the viscoelastic behaviour of seat materials used in ball valve. This device simulates the contact configuration and the loading conditions produced during service process (opening-closing valve). The originality of such tribometer lies in the possibility of coupling/decoupling the stress relaxation from the tribological behaviour that allows the evaluation of the interaction between tribology and viscoelastic behaviour. Besides, the tribometer concept and manufactured solution of the same subassemblies as well as the measure system and software for data acquisition and processing results are described. This paper also reports the results of a very first set of experiments conducted on polytetrafluoro ethylene materials under dry rolling conditions. The results obtained show a good correlation with the results found in literature, which encourages more investigation into seats ball valve.