MEGA Corp. MMP4-2 - Manual (Page 17)

MMP 4-2
5 Nov 2011
SECTION 4
Basic Hydraulics System
4-2
HYDRAULIC PUMP
The hydraulic pump is coupled to the flywheel
end of the engine. The hydraulic pump moves
the oil through the system to generate flow and
pressure needed to operate the water pump and
boom cylinders. The pump draws oil from the
hydraulic tank and moves it to the hydraulic
control valve.
HYDRAULIC CONTROL VALVE
The hydraulic control valve directs and
regulates the hydraulic pumps oil flow. The
valve operates the boom lifting cylinders by
pressurizing the rod end of the cylinder to make
the booms move up (Cylinder retract). To
lower the booms the valve opens to allow the
oil to return to the hydraulic filter through a
metering control that controls the speed of the
cylinder movement. The hydraulic drive motor
for the water pump portion of the control valve
is equipped with a detent to allow the valve
spool to stay in an open position when the lever
is moved to the ON position for normal water
pump operation. When this lever is moved to
OFF it will shut off hydraulic oil flow to the
water pump drive motor. The hydraulic control
valve is fitted with a pressure regulator that
limits the maximum pressure of the hydraulic
system to 2,100 psi (14,450 kpa). The excess
oil flow is diverted to the hydraulic oil filter.
When the control valves are in the neutral
position, all of the hydraulic oil by-passes
through the control valve to the return
hydraulic oil filter.
WATER PUMP HYDRAULIC
DRIVE MOTOR
The hydraulic drive motor is coupled to the
water pump drive shaft inside the water pump.
The drive motor is controlled by the hydraulic
control valve, water pump spool. When the
lever is moved to the ON position the fluid is
directed to the drive motor causing the water
pump impeller to rotate, moving water up the
inlet boom.