Rotary fluid handling machine having reduced fluid leakage

A rotary working fluid handling apparatus for processing working fluid between a high pressure and a low pressure comprising:

• (A) a stationary housing;
• (B) a rotor comprising (i) a shaft axially aligned for rotation within said stationary housing, (ii) at least one wheel mounted on said shaft, said wheel having a plurality of flow paths establishing flow communication between essentially radially directed and axially directed openings, and (iii) an annular seal for preventing working fluid from leaking past the back of said wheel positioned at a lesser radial distance from said shaft than the greatest radial distance from said shaft of said axially directed openings;
• (C) at least one thrust bearing capable of transmitting an axial thrust load between said rotor and said stationary housing;
• (D) means for determining said axial thrust load;
• (E) a balancing chamber sealed from the bearing defined by said rotor and said stationary housing;
• and
• (F) fluid flow conduit means connected at one end of said balancing chamber and at the other end through valve means to at least one pressure source at a pressure at least equal to said high pressure and to at least one pressure sink at a pressure at most equal to said low pressure, said valve means being responsive to said axial thrust load determining means, whereby the net axial thrust load on said thrust bearing is essentially zero.