Spray Pump Drive Circuit - Toro Multi Pro 5800 Service Manual

Spray Pump Drive Circuit

A two (2) section gear pump is coupled to the piston
(traction) pump. The front gear pump section (closest to
the piston pump) supplies hydraulic flow to the spray
pump drive circuit. The rear gear pump section supplies
hydraulic flow to both the steering and spray boom lift/
lower circuits. The gear pump takes its suction from the
hydraulic reservoir. Spray pump circuit pressure is limit-
ed to 2000 PSI (138 bar) by a relief valve located in the
spray pump control manifold.
Spray pump drive circuit hydraulic flow can be moni-
tored at the outlet of the front gear pump section. Circuit
pressure can be measured at a diagnostic fitting in port
G on the spray pump control manifold.
Hydraulic flow control for the spray pump drive motor is
completed by the spray pump control manifold. The
pump control manifold includes a solenoid controlled
proportional control valve (PV) that allows the operator
to adjust hydraulic flow to the spray pump motor. The
spray pump on/off and application rate (increase/de-
crease) switches are used to adjust electrical current to
the control manifold solenoid.
Spray Pump Switch OFF (Fig. 13)
With the engine running and the spray pump switch in
the OFF position, the solenoid valve in the spray pump
control manifold is not energized. All gear pump flow to
the manifold is routed through the pressure compensa-
tor valve (LC) in the manifold, directed out the T port of
the manifold, to the oil cooler and returns to the hydraulic
oil reservoir. The spray pump hydraulic motor receives
no hydraulic flow so the spray system pump is not ro-
tated and no spray system flow is available.
Spray Pump Switch ON (Fig. 12)
With the engine running and the spray pump switch in
the ON position, the solenoid valve in the spray pump
control manifold is energized. Based on available cur-
rent (mA) from the spray pump application rate (in-
crease/decrease) switch, the spool in the proportional
control valve directs some gear pump flow out the M1
port to the spray pump hydraulic motor. This hydraulic
flow causes the motor to rotate the spray system pump
for spray system operation. The manifold pressure com-
pensator valve (LC) maintains a pressure differential of
80 PSI (5.5 bar) across the proportional control valve
(PV). Any excess flow above what the proportional con-
trol valve is electrically adjusted for, is by--passed to the
reservoir through the compensator valve. Hydraulic flow
returns out the manifold T port, to the oil cooler and then
to the hydraulic oil reservoir.
Multi Pro 5800
The spray pump application rate (increase/decrease)
switch allows the operator to adjust electrical current to
the proportional control valve (PV) solenoid. Higher cur-
rent (rate increase) to the proportional control valve so-
lenoid increases hydraulic flow to the spray pump motor
and results in a higher spray pump speed with more
spray system output/pressure. Lower current (rate de-
crease) to the proportional control valve solenoid de-
creases hydraulic flow to the spray pump motor and
results in a lower spray pump speed with less spray sys-
tem output/pressure.
G
Spray Pump Switch in OFF Position
(Spray Pump Motor NOT Rotating)
Page 4 - - 17
SPRAY PUMP
6.0
M1 M2
CV
OR1
.040
80 PSI
PV
LC
2000 PSI
RV
SPRAY PUMP
P T
CONTROL
MANIFOLD
Figure 13
Hydraulic System