Hydraulic apparatus and method

Claim 1

IN A HYDRAULIC SYSTEM WHEREIN A SYSTEM PUMP SUPPLIES HYDRAULIC FLUID UNDER RELATIVELY HIGH PRESSURE TO A MOTOR ELEMENT UNDER THE CONTROL OF A VALVE ELEMENT, A NOVEL DUAL RESERVOIR SYSTEM FOR SUPPLYING A VOLUME OF CLEAN, COOL HYDRAULIC FLUID COMMENSURATE WITH VARYING MOTOR ELEMENT DEMANDS TO SAID SYSTEM PUMP AT SUPERATMOSPHERIC PRESSURES SUBSTANTIALLY LESS THAN THE OUTPUT PRESSURE OF SAID SYSTEM PUMP COMPRISING FIRST AND SECOND RESERVOIRS SEPARATE AND DISTINCT FROM ONE ANOTHER, SAID FIRST RESERVOIR BEING VENTED TO THE ATMOSPHERE AND SAID SECOND RESERVOIR BEING SEALED FROM THE ATMOSPHERE AND SUPPLYING FLUID DIRECTLY TO SAID SYSTEM PUMP, A VALVE CONDUIT INTERCONNECTING SAID RESERVOIRS, A SUPPLY PUMP INTERPOSED IN SAID INTERCONNECTING CONDUIT AND INTERMITTENTLY SUPPLYING MAKE-UP FLUID TO SAID SYSTEM RESERVOIR AT SUPERATMOSPHERIC PRESSURE LESS THAN THE PRESSURE SUPLIED BY SAID SYSTEM PUMP, RECIRCULATING MEANS DISCHARGING USED FLUID INTO SAID INTERCONNECTING CONDUIT MERGEABLE WITH THE INTERMITTENT FLOW OF MAKE-UP FLUID, A FILTER AND A HEAT EXCHANGER INTERPOSED IN SAID INTERCONNECTING CONDUIT BETWEEN SAID SUPPLY PUMP AND SAID SECOND RESERVOIR DOWNSTREAN OF SAID RECIRCULATING DISCHARGE FOR CLEANING AND COOLING ALL FLUID FLOW PRIOR TO DELIVERY INTO THE SECOND RESERVOIR.