MODEL 66-80 VIBRATORY DRIVER/EXTRACTOR
V. HYDRAULIC CIRCUITRY
B. VIBRATOR DRIVE (CONTINUED)
Full motor speed is reached within a few seconds and the motor drive pressure is
indicated by GAGE (GA1). Maximum drive pressure is limited to approximately
5500 PSI (379 Bar) by the FORWARD RELIEF VALVE (RV1). The RELIEF
VALVE (RV1), if opened by over pressure, permits a small pilot flow from cartridge
(C2). This pilot flow causes cartridge (C2) to partially open and allows some or all
of the pump flow to return to the reservoir. Oil exiting VIBRATOR MOTORS (M)
opens cartridge BV and returns to the power unit. Cartridge BV opens easily
because its pilot flow is "vented" by BRAKE VALVE (RV5). BRAKE VALVE (RV5)
is held open by pressure coming from the motor drive FORWARD system. Case
drain oil from the motors returns to the reservoir. Case drain pressure is limited to
65 PSI (4.5 Bar) by the CASE DRAIN RELIEF VALVE (RV3). Oil returning to the
power unit returns to the reservoir through COOLER VALVES (V3), HEAT
EXCHANGER (HE) and RETURN FILTERS (F2).
Pushing the STOP button on the control pendant, de-energizes the CONTROL
VALVE (V2) and "vents" (open) cartridge C2, allowing pump flow to go directly
back to the reservoir. When pressure is removed from the drive FORWARD
system, the BRAKE VALVE RELIEF (RV5) closes and blocks the pilot flow to
BRAKE VALVE (BV) cartridge, causing it to close. Maximum brake pressure
generated by BRAKE VALVE (BV) is limited by BRAKE VALVE RELIEF (RV5) TO
2000 PSI (138 Bar). This 2000 PSI (138 Bar) back pressure rapidly brakes the
motors (M) to a stop.
Hydraulic oil temperature is regulated by the COOLER VALVES (V3). When oil
temperature is below 100°F (38°C), V3 directs the flow directly to the reservoir
through FILTER (F2). When oil temperature exceeds 100°F (38°C), COOLER
VALVE (V3) directs flow through the HEAT EXCHANGER (HE) before it enters the
reservoir, through FILTER (F2). Excessive pressure in the HEAT EXCHANGER
(HE) is prevented by CHECK VALVES (CV3 & CV4), which bypasses excess flow
and limits pressure to 65 PSI (4.5 Bar).
The quick-disconnect couplers (QD1, QD2, and QD5) permit de-coupling of the
drive and case drain hoses at the power unit.
V-2
