Since their inception, the reliability and mean time between failure of mechanical seals fitted to pumps have been inconsistent. Operational experience shows that seal performance varies relative to application, pump type and manufacture. A significant amount of research in seal face materials, hydraulic and thermal face distortion, face lubrication, seal cooling, etc., has been carried out by a number of mechanical seal makers and, while Large strides in technology and seal performance have been achieved, the ultimate  breakthrough which will give consistent high reliability mechanical seals has still to be made.

As a contribution towards achieving this step change in operation, the pump maker should recognize those design and manufacturing aspects of pump design that affect the seal performance and, where necessary, alter pump design philosophy to ensure the pump to seal interface is idealised not only from the standpoint of the pump, but also from that of the mechanical seals. Here followed some requirement for the pump.

A. Radial runout of shaft < 0.03mm
B. Coaxiality of shaft and sealing chamber > 0.02mm
C. Verticality of shaft and sealing face < 0.05mm
D. Axial float <0.01 mm
E. Amplitude of vibration of the shaft during running <10um