NPK M20C, Instruction Manual, Page: 38 / 152

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38
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PROCESSOR – BOOSTER AND CYLINDER
III OPERATING PRINCIPLE
Fig. 7
VALVE SHIFT TO FORWARD STROKE
When the booster piston (c14) reaches
full reverse stroke, oil drains out of the
plunger (c19) end of the main control
valve (c15) through ports C2 (c27) and
C3 (c28) of the booster piston. The
main control valve spring moves the
main control valve spool toward the
plunger. This places the main control
valve in position to direct oil to the
booster piston to start the next forward
piston stroke. These forward and
reverse piston strokes will continue as
long as the excavator’s control valve
(k7) is shifted to send hydraulic flow to
the booster and cylinders and that
there is sufficient resistance ( load ) to
keep the booster active.
c14
Booster Piston
c15
Main Valve Assembly
c19 Plunger
c27 Port C2 Piston
c28
Port C3 Piston
k7
Carrier Control Valve
fl1
High Pressure Hydraulic
Flow
fl2
Low Pressure Hydraulic
Flow
fl3 Intensified Hydraulic Flow