HEAT EXCHANGER GP-SEA WATER 2461102 - Caterpillar

Hydraulic Schematic for the Main Control Valve
Illustration 1 g03810218
Main control valve (1) Bucket control valve (2) Boom control valve (3) Right travel control valve (4) Left travel control valve (5) Stick control valve (6) Attachment control valve (7) Valve (8) Swing control valve (9) Blade control valve (10) Swing control valve (11) Inlet Port (12) Return port (13) Return portThe main control valve is located in the hydraulic system between the main pump and the actuators (cylinders and motors). According to the machine operation, components in the main control valve control the flow of pump oil. The components also control the pressures in the circuits for the pilot pump. In this way, the operating speed and directions of the cylinders and motors are changed, and the pressure of the pump oil is controlled.Operation and Functions
Illustration 2 g01210873
Main control valve (1) Bucket control valve (2) Boom control valve (3) Right travel control valve (4) Left travel control valve (5) Stick control valve (6) Attachment control valve (8) Swing control valve (9) Blade control valve (10) Swing control valve (11) Inlet Port (12) Return portThere are nine major valves in the main control valve. Oil is directed from the pumps to these valves in the following manner:Oil from the main pump enters the main control valve through inlet port (11) .The major valves in the main control valve have the following functions:Control in the NEUTRAL position - When the joysticks are in the NEUTRAL position, oil passes through the unloader valve in the main control valve. The oil is exhausted through return ports (12) and (13) .Operation of individual valves - Individual valves are used in extending the cylinder rods and retracting the cylinder rods. These valves are also used to actuate the hydraulic motors. Pump oil is supplied to the valves through the center bypass passage and the parallel feeder passages.Prevention of leakage and drift in cylinders and motors - This function is performed through the use of load check valves.Release of the swing brake - Oil under pressure is required to release the swing brake.Limitation of circuit pressure - This function is performed through the use of relief valves.Straight travel - The straight travel control enables the machine to continue straight travel even though an implement or the attachment is used.Individual Valve Operation
Illustration 3 g01210920
Bucket control valve (NEUTRAL position) (1) Cylinder port A (2) Pressure compensator valve (3) Cylinder port B (4) Pa port (5) Neutral passage (6) Tank passage (7) Pb port (8) Load check valveWhen the joysticks are in the NEUTRAL position cylinder port A (1) and cylinder port B (3) are closed to pump oil.
Illustration 4 g01210923
Bucket control valve in activated modeBucket control valve (NEUTRAL position) (1) Cylinder port A (2) Pressure compensator valve (3) Cylinder port B (4) Pa port (5) Neutral passage (6) Tank passage (7) Pb port (8) Load check valveWhen pilot oil enters Pa port (4) , the spool shifts and pump oil in neutral passage (5) pushes up pressure compensator valve (2) and load