Abstract: A mechanical face seal is provided that incorporates fluid passages through either or both of a first and a second element of the seal for directing a flow of cooling fluid to an exposed area of the second element which extends radially outward beyond the contact area of the seal. The fluid passages are configured and oriented to provide more cooling flow through each seal element and over the surfaces of each seal element then is achievable with prior cooling and lubrication approaches, to thereby enhance heat dissipation from the elements of the seal to such a degree that lubrication, seal life and performance of the seal are improved. In preferred embodiments of the invention, the seal elements are specially configured to create an annular gap between the elements for centrifugally pumping fluid away from a contact area of the seal.

Abstract: Cavitation in axial piston motors (20) caused to act as a pump by an aiding load (28), and the related difficulty of loss of hydrostatic film (52), and tipping or hammering of motor slippers (64), can be reduced by a method which includes the step of recirculating hydraulic fluid from the supply port (18) of the motor (20) to the return port (30) of the motor (20) upon the occurrence of an aiding load (28).