Analysis of Double Seat Seal of Ultra High Pressure Flat Gate Valve

Abstract

As an important part of the Christmas tree, the sealing performance of the flat gate valve is very important, and the O-ring seal is the most commonly used seal in the flat gate valve. Therefore, the research on O-rings is particularly important. For the flat gate valve with a single gate, its structure has gradually developed from a single seat seal to a double seat seal. This article mainly analyzes the sealing principle of the double seat in the ultra-high pressure flat gate valve and the influence of the pre-tightening force of the sealing ring on the sealing effect. Using finite element analysis software, a two-dimensional axisymmetric model of the double valve seat sealing structure was established to study the non-metallic sealing performance of the valve seat. The Mises stress, the maximum contact stress of the sealing surface, and the contact area of the sealing surface of the O-ring seal under different compression ratios are analyzed. The results show that when only the sealing performance and pre-tightening force requirements are considered, an O-ring with a larger wire diameter should be selected as much as possible. When considering the service life of the O-ring seal, the compression rate of the seal ring should not exceed 20%. Therefore, the selected seal ring wire diameter is 3.75mm within the recommended seal ring compression rate range.