Directional Control Valve; Pressure Relief Valve - Wittke StarLight Maintenance Manual

Cap on quick
coupler
64
D C
IRECTIONAL
Pressurized oil is directed from the hydraulic pump to a bank of
stack-type directional control valves mounted on the front
header of the W
ITTKE
section.
The valve bank on a commercial unit is comprised of:
a Inlet Section: the oil enters the valve bank through
the top of the inlet section where it is then directed to
the work sections below. The pressure test port is
located at the front of the inlet section. Remove the
cap on the quick coupler and install a pressure
gauge to read the system operating pressure.
b Working sections: hopper top door, tailgate, arms,
forks and pack circuits are controlled by a work
section dedicated to each function. Air actuators
attached to the work section shift the spool in the
desired direction to allow pressurized oil to operate
the hydraulic cylinders. Returning oil is allowed to
escape to tank via the return passage, outlet section
and return lines.
c Outlet Section: caps the bottom of the valve bank
to provide a path for returning oil to travel to the
return line filter in the tank.
P R
RESSURE ELIEF
The pressure relief valve is fitted in the inlet section of the valve
bank and protects the hydraulic components from damage
caused by loads in excess of 2500 psi (S
2750 psi (S
UPERDUTY
the relief valve, the oil overcomes the adjustment spring and
opens the relief valve allowing oil to return to the tank.
V
ONTROL ALVE
body. Rubber gaskets seal each valve
V
ALVE
TARLIGHT
™). When pressure exceeds the setting of
™) or
Part #: 90309