PRESSURE AND FLOW COMPENSATOR VALVE GROUP 1336727 - Caterpillar

The pilot oil in port (20) of control valve (16) also moves stem (36) to the left against the force of spring (35). Lower pump oil from parallel feeder passage (7) now flows through passage (34), passage (37), check valve (13) and flows out of port (15) to line (9). The oil then combines with the upper pump oil in line (3). The combined pump oil flows to the head end of boom cylinders (1) .Return oil from the rod end of boom cylinders (1) flows through line (2) to control valve (19). The oil then flows through passage (30), return passage (18) and return line (22) and back to the hydraulic tank.Boom Raise (Low Speed)
When the boom control lever is moved less than half of the travel distance for BOOM RAISE, full pilot oil pressure will never be supplied to control valve (16) and control valve (19) .When the boom is raised at a slow speed, control valve (19) opens and control valve (16) remains closed. The force of spring (31) in control valve (19) is less than the force of spring (35) in control valve (16). Pilot oil pressure will open control valve (19) before control valve (16) .Only upper pump oil now flows to the head end of boom cylinders (1). Without lower pump oil, the cylinder rod movement slows down when the boom is raised.Hydraulic Schematic for Boom Lower
Illustration 5 g00670688
(1) Boom cylinders (2) Line (3) Line (4) Drain line (5) Check valve (6) Boom lowering control valves (7) Pilot line (8) Passage (9) Spool (10) Line (11) Center bypass passage (12) Load check valve (13) Control valve (boom I) (14) Center bypass passage (15) Control valve (stick II) (16) Center bypass passage (17) Orifice (18) Line (19) Parallel feeder passage (20) Return passage (21) Check valve (22) Port (23) Pilot line (24) Port (25) Shuttle valve (26) Pilot line (27) Pilot line (28) Pilot line (29) Shuttle valve (30) Upper pump (31) Pilot pump (32) Pilot control valve (bucket and boom) (33) Pilot line (34) Lower pumpBoom Lower
Introduction
When the boom is lowered, oil from upper pump (30) is supplied to boom cylinders (1) through control valve (13) .Control valve (13) contains a regeneration circuit for check valve (21). When the control lever is moved