Abstract: A pump assembly which overcomes a shaft and cover cracking problem comprising a means for heating the seal purge water flowing along the shaft before it exits into an annulus (mixing region) thus reducing the temperature difference between the cooler seal purge water and the hotter product water prior to the mixing of the two waters.

Abstract: A single or multiple stage mechanical seal assembly in which one seal ring is resiliently coupled to a rotatable shaft and the other seal ring is resiliently urged toward the first seal ring by axially-arranged identical springs received in spring pockets in a spring retainer, some pockets opening at one radial surface of the retainer and others opening at the other radial surface of the retainer. The outer surfaces of the seal rings are protected against deflection by being encircled by cylindrical members and one seal ring is resiliently coupled to its encircling cylindrical member. A balance sleeve means partly supports the axially movable seal ring and is capable of angular adjustment to compensate for shaft misalignment.