Gas Buffer Seal

The figure presents a simplified view of a shaft seal that provides a small flow of neutral buffer gas to prevent contact between different gases contained in two adjacent regions along the shaft. In the original application, the shaft couples a hydrogen-burning turbine with a high-pressure oxygen pump, and helium is used as the buffer gas to prevent hydrogen/oxygen contact along the shaft. Other potential applications could involve the use of helium or other buffer gases or liquids to prevent mixing of fluids or to prevent escape of process fluids that are poisonous, odorous, or harmful to equipment or to the environment.