GAUGE (OIL TEMPERATURE) 6215023 - Caterpillar

Illustration 1 g00923903
Drift reduction valve (1) Relief valve (5) Manual lowering valve
Illustration 2 g00964200
Neutral (1) Relief valve (2) Resolver check valve (3) Load check valve (4) Line from control valve (5) Screw for manual lowering (6) Pilot piston (7) Line from pilot valve (8) Spring chamber (9) Port to cylinder (10) Ball check valves
Illustration 3 g00964580
Stick in or lowering of VA boom (1) Relief valve (2) Resolver check valve (3) Load check valve (4) Line from control valve (5) Screw for manual lowering (6) Pilot piston (7) Line from pilot valve (8) Spring chamber (9) Port to cylinder (10) Ball check valvesThe drift reduction valves for the VA boom cylinder head end and for the stick cylinder rod end are pilot controlled valves. The drift reduction valve will prevent circuit leakage in the main control valve when the implement control valve is in the NEUTRAL position.While the implement is in the NEUTRAL position and a load is raised, the static pressure from the load goes into the drift reduction valve at port (9). This forces load check valve (3) against the seat. This blocks the oil return flow. Now, the cylinder position will be maintained.Load check valve (3) is opened by pilot controlled pressure (7) in order to permit the oil in spring chamber (8) behind load check valve (3) to return to the tank. The pressure in spring chamber (8) decreases and double check valve (10) opens in order to return the cylinder oil to the tank. The effective area at the cylinder port at load check valve (3) and the static pressure from the cylinder is now able to open load check valve (3). The oil is now able to drain through the control valve.When the main control valve is activated to the STICK OUT position or to the VA BOOM RAISE position, the pump pressure is applied against the bottom end of load check valve (3). When the pump pressure increases beyond the force of the spring for load check valve (3), load check valve (3) opens in order to provide pressure to the cylinder.The relief valve in the drift reduction valve opens when the circuit pressure between the cylinder and load check valve (3) exceeds the setting of relief valve (1). When relief valve (1) opens, oil is sent to the opposite end of the cylinder in order to lower the load.The VA boom or the stick can be lowered manually if pilot pressure is lost. Manual lowering screw (5) moves pilot piston (6) downward in order to lower the implement without pilot pressure.