Apparatus and method of sealing a valve against increasing fluid pressure

摘要

A double lobed seal comprises first and second annular seals, each having a radially inwardly projecting annular lobe that engages against a sealing surface of a valve element in a valve housing to seal the valve element in its closed position. With increasing fluid pressure exerted on the dual lobe seal, the upstream seal is compressed and moves radially away from the valve element sealing surface. This movement allows the fluid under pressure to enter a void between the two annular seals. The increasing fluid pressure in the void exerts a compressive force on the downstream annular seal that causes its annular lobe to move radially inwardly increasing the force of its sealing engagement with the disk valve sealing surface. In this manner, the dual lobe seal increases its sealing effectiveness when subjected to increasing fluid pressures.