Hydrostatic Seal Design

The literature contains numerous references to applications where the designer has utilized the advantages of non-contacting hydrostatic seals to solve problems of operating under conditions of high speeds, pressures and temperatures. Examples vary from gas designs for turbines and compressors to liquid applications such as boiler feed pumps and liquid-sodium pumps for nuclear reactors. It is the view of the authors that this type of seal, proved under these very difficult operating conditions, has considerable advantages when compared to ‘balanced’ mechanical face seals. In this paper, the principles of operation of hydrostatic seals are presented and design data are given for orifice-, capillary- and slot-controlled designs, including a comparison of their performances under variable-temperature conditions. A method for optimizing the location of the seal groove is presented.