Improvement Of A High Temperature Bellows Seal

Abstract

An Inconel 718 metal bellows seal has been developed to meet the demands for high temperature applications in corrosive media such as high Sulphur bearing crude oil. Finite element analysis was used to develop concepts having low seal face distortion at high temperatures and to minimize bellows stress. Laboratory testing at temperatures to 700 degrees F demonstrates that the final seal design exhibits both low leakage and low wear. A thick plate bellows construction provides high resistance to corrosion, fatigue, and pressure stress. The Inconel 718 bellows was evaluated for resistance to shear and fatigue failure in dry running tests using silicon carbide vs silicon carbide faces. This resulted in heavy damage to the silicon carbide faces, but in every test the Inconel bellows were intact and helium leak tight afterwards. The seal has a sufficient number of diaphragms to accommodate seal setting tolerance and shaft axial growth during thermal warm up of a pump.