THE FUNDAMENTAL SEALING CHARACTERISTICS EVALUATION FOR METAL HOLLOW O-RING GASKETS

Metal hollow O-ring gaskets have been used in bolted flanged connections for high-pressure piping. Some studies have been conducted on their deformation characteristics. However, the sealing performance of the connections, which is important for practical use, has not been fully elucidated. The purpose of this study is to investigate the effects of metal hollow O-ring under compression on the sealing performance. So, the effects of the thickness ratio of O-ring to the diameter of it on the sealing performance are examined using both FEM stress analysis and the leakage measurements in platen tests. A helium leak detector was used to measure the amount of leakage from the O-ring alone in the platen test, and the compression behavior was investigated using FEM analysis to show the relationship between the contact stress and the amount of leak rate. As a result, it is demonstrated that the leak rate can be predicted using the maximum contact stress. Additionally, the relationship between the contact force. per unit length (load per unit length) and the displacement for bolted flange connections with O-ring gaskets is examined both experiments and the FEM analysis.