Porting arrangement for balancing valve of fluid pressure device

Claim 1

A ROTARY FLUID PRESSURE DEVICE COMPRISING A CASING, FLUID INLET AND OUTLET MEANS, AN INTERNALLY TOOTHED RING MEMBER, A COOPERATING EXTERNALLY TOOTHED STAR MEMBER HAVING FEWER TEETH THAN SAID RING MEMBER DISPOSED ECCENTRICALLY RELATIVE TO THE AXIS OF SAID RING MEMBER, ONE OF SAID MEMBERS HAVING ROTATIONAL MOVEMENT ABOUT ITS OWN AXIS AND ONE OF SAID MEMBERS HAVING ORBITAL MOVEMENT ABOUT THE AXIS OF THE OTHER OF SAID MEMBERS WITH THE TEETH OF SAID MEMBERS INTERMESHING IN SEALING ENGAGEMENT TO FORM EXPANDING CELLS ON ONE SIDE OF THE LINE OF ECCENTRICITY AND CONTRACTING CELLS ON THE OTHER SIDE OF SAID LINE DURING RELATIVE MOVEMENT BETWEEN SAID MEMBERS, FIRST AND SECOND RELATIVELY MOVABLE VALVE ELEMENTS HAVING RESPECTIVE FIRST AND SECOND SLIDABLY ENGAGING SURFACES WITH ONE OF SAID VALVE ELEMENTS BEING MOVABLE IN SYNCHRONISM WITH ONE OF SAID MOVEMENTS OF ONE OF SAID MEMBERS, SAID FIRST VALVE ELEMENTS HAVING A PLURALITY OF PASSAGES COMMUNICATING WITH SAID EXPANDING AND CONTRACTING CELLS AND HAVING PASSAGE OPENINGS DEFINED IN SAID FIRST SURFACE ARRANGED CIRCUMFERENTIALLY RELATIVE TO THE AXIS THEREOF, SAID SECOND VALVE ELEMENT HAVING PORTS HAVING OPENINGS DEFINED IN SAID SECOND SURFACE ARRANGED CIRCUMFERENTIALLY RELATIVE TO THE AXIS THEREOF, SAID PORTS INCLUDING A FIRST GROUP OF PORTS HAVING CONSTANT FLUID COMMUNICATION WITH SAID INLET MEANS AND A SECOND GROUP OF PORTS HAVING CONSTANT FLUID COMMUNICATION WITH SAID OUTLET MEANS, SAID FIRST VALVE ELEMENT PASSAGE OPENINGS BEING REGISTERABLE WITH AT LEAST A PORTION OF SAID SECOND VALVE ELEMENT PORT OPENINGS DURING RELATIVE MOVEMENT BETWEEN SAID MEMBERS TO DIRECT FLUID FROM SAID FLUID INLET MEANS TO SAID EXPANDING CELLS AND TO DIRECT FLUID FROM SAID CONTRACTING CELLS TO SAID FLUID OUTLET MEANS, AND A PLURALITY OF CIRCUMFERENTIALLY ARRANGED FLUID PRESSURE BALANCING RECESSES IN SAID FIRST VALVE SURFACE HAVING OPENINGS IN SAID FIRST SURFACE WHICH ARE ALTERNATELY AND SYMMETRICALLY ARRANGED RELATIVE TO SAID PASSAGE OPENINGS AND ARE EQUAL IN NUMBER TO SAID PASSAGE OPENINGS.