Seal for rotary hydraulic machine

Claim 1

IN A ROTARY HYDRAULIC MACHINE COMPRISING A STATIONARY HOUSING, A ROTATING MEMBER, SAID MEMBER COMPRISING SPACED AXIALLY UPPER AND LOWER SHROUDS HAVING BLADES SECURED THEREBETWEEN, AND DEFINING A FLUID FLOW CHANNEL, SAID LOWER SHROUD HAVING A HIGH PRESSURE EDGE AT A LARGE DIAMETER THAN THE LOW PRESSURE EDGE, SAID STATIONARY HOUSING HAVING A PORTION SURROUNDING SAID HIGH PRESSURE EDGE OF SAID LOWER SHROUD TO COOPERATE THEREWITH TO PROVIDE A CLOSE RUNNING CLEARANCE THEREBETWEEN, SAID STATIONARY HOUSING HAVING A SECOND PORTION EXTENDING FROM SAID FIRST PORTION TOWARD SAID LOW PRESSURE EDGE OF SAID LOWER SHROUD AND SPACED THEREFROM TO DEFINE AN ANNULAR SPACE BETWEEN SAID LOWER SHROUD AND THE STATIONARY HOUSING, SEALING MEANS BETWEEN THE LOWER SHROUD ADJACENT ITS LOW PRESSURE EDGE AND THE SECOND PORTION OF THE STATIONARY STRUCTURE EXTENDING TOWARD THE LOW PRESSURE EDGE, SAID SEALING MEANS BETWEEN SAID LOWER SHROUD AND THE SECOND PORTION OF SAID STATIONARY STRUCTURE COMPRISING A PAIR OF SEAL ELEMENTS, ONE OF SAID PAIR OF SEAL ELEMENTS BEING REPLACEABLE AND CARRIED BY THE ANNULAR SPACE AND COSTATIONARY STRUCTURE ADJACENT THE ANNULAR SPACE AND COOPERATING WITH SAID STATIONARY STRUCTURE TO DEFINE ONE SIDE OF AN ANNULAR RECESS IN SAID SECOND PORTION OF SAID STATIONARY STRUCTURE, THE SECOND OF SAID SEAL ELEMENTS DEFINING THE LOW PRESSUE EDGE OF SAID LOWER SHROUD AND HAVING AN ANNULAR OUTWARD PROJECTION THEREON EXTENDING INTO SAID ANNULAR RECESS AND OVERLAPPING SAID FIRST SEAL ELEMENT, MEANS FOR INJECTING HIGH PRESSURE AIR INTO THE ANNULAR SPACE BETWEEN THE LOWER SHROUD AND THE SECOND PORTION OF THE STATIONARY HOUSING, AND MEANS TO INJECT A HIGH PRESSURE LIQUID LUBRICANT INTO SAID ANNULAR RECESS TO PREVENT ESCAPE OF AIR PAST THE LOW PRESSURE EDGE OF SAID LOWER SHROUD INTO SAID FLUID FLOW CHANNEL.