ABSTRACT
Centrifugal seals utilize the radial pressure rise in a rotating liquid ring to generate a sealing effect. This “centrifugal pressure” either counterbalances the pressure of a process liquid or forms a liquid barrier against a process gas. Rotation of the liquid ring is generated either by a rotating cylindrical housing or a rotating disk in a housing. The moving parts of centrifugal seals do not contact and hence there is no rubbing wear. However, the sealing action vanishes when the shaft speed is low or zero and an additional contact seal is required if leakage is not tolerable under these conditions. At higher speeds, when the centrifugal seal is able to counterbalance the process pressure, centrifugally activated levers press the seal ring against the closing springs to separate the seal faces. Another feature of this design that contributes to sealing are the additional vanes on the back of the pump impeller.
