Only self aligning and stationary designs can compensate for this movement and pass fugitive emission standards. Unfortunately many stationary seal designs are cartridge mounted to facilitate easier installation. It is always desirable to use less flushing water, or to eliminate it completely. Seals with springs in the sealing fluid are more likely to clog with solids than those designs where the springs are placed outside the fluid. Springs in the sealing fluid are also more sensitive to corrosion because of their high stress.
Balanced seals generate less heat and therefore require less cooling.
Suction recirculation makes sense in most applications with the exception of those applications that are being sealed near their vapor point, fluids containing solids with a low specific gravity, double suction, single stage pumps, and most Durco semi- open impeller designs It is always better to use clearly identifiable seal materials. You must know what material and grade of material is being used in the component to make a sensible decision as to what went wrong. Superior, universal materials are better than individually selected materials that are chosen to satisfy only one set of operating conditions. The number of spare parts can be reduced significantly. Flushing fluids and cleaning chemicals may attack the carefully selected low cost materials.