2.14
Pinto BT-POM 1212 - Revision 5
Pre-Operation
Speed adjustment fl ow-control valve.
2 Open the speed adjustment fl ow-
control valve fully by winding it out
anti-clockwise – this must be done
prior to engaging your hydraulics
3 Engage the hydraulic control in the
cab of the tractor
4 Close the speed adjustment fl ow-
control valve slowly by turning it
clockwise until the desired RPM of
the pump is reached. Ensure the
RPM DO NOT exceed 540.
Consult your Croplands dealer if you require
assistance with determining pump RPM.
The dealer will be able to calibrate this using an
RPM meter or rev counter.
NOTE
Hook-up
Open Centre vs Closed
Centre Hydraulics
For the best operation of your hydraulic-
drive Diaphragm pump or hydraulic-drive
fi lling pump, there are some adjustments
that can be made by your dealer on your
tractor hydraulics for best performance
& lower heat generation to protect your
tractor.
In general terms, there are three systems,
which are described below:
Open Centre Systems
In an open centre system, the hydraulic
pump on the tractor puts out a constant
fl ow. If the pump puts out more oil than the
hydraulic-drive motor can use, a portion
of the oil must be bypassed around the
motor.
When the oil is bypassed around a loop
and does no work, the energy put into it
by the pump turns into heat. Therefore, the
amount of oil bypassed should be kept to
a minimum.
Tractor adjustments may be necessary,
consult your dealer if you are unsure.
Closed Centre (Pressure
Compensated) Systems.
The closed centre pressure-compensated
system has a variable displacement pump
which will deliver fl ow at the necessary rate
to maintain a specifi ed pressure.
It is best to have the pump operating at
around 1800 to 2100 psi with the relatively
low-fl ow hydraulic drive motor fi tted to the
Pegasus (if fi tted).
Tractor adjustments may be necessary,
consult your dealer if you are unsure.
Closed Centre Load Sensing
Systems (Flow and Pressure
Compensating).
The closed centre flow-compensated
system is a variation of the pressure-
compensated system, designed primarily
for more efficient operation and the
generation of less heat.
It works on the principle of maintaining a
constant pressure drop from the pump to
the work port of the selector valve.
Any variation in the demand at the motor
will cause a change in fl ow.
The system senses this change in fl ow
due to the change in pressure drop
across the valve, and causes the pump
to compensate by varying the pump fl ow.
No restrictor is required in the pressure
line and no oil is bypassed.
Check with your dealer to see if your
tractor has this system.
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