The paper presents an quantitative assessment of the wear process of the sealing ring made of pure PTFE cooperating with steel ball of the industrial valve. The three variants of the sealing PTFE ring differing in shape were taken into consideration. In the first stage the numerical simulation by means of Finite Element Method was used to determine the contact pressure between the steel ball and PTFE seal ring. In the second stage the experimental test was carried out to check the wear rate of

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... he PTFE ring. The DN50 PN10 industrial ball valve was subjected to 1000 of the closing/opening cycles. In the three variants of the sealing ring the friction torque necessarily to open and close of valve was measured. The weight loss due to wear was determined which was the assessment of the wear degree in macro-scale. As a wear in a micro-scale the roughness parameter on the contact surface of the PTFE ring was taken as an index.