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The hydraulic yaw suspension system uses hydraulic
cylinders and nitrogen filled accumulators to dampen
and control the back and forth sway (yaw) of the
booms.
The hydraulic yaw system is a closed hydraulic circuit.
The base of the right hand yaw cylinder is connected
via hydraulic hoses to the rod end of the left hand
cylinder. A nitrogen charged accumulator (70 bar
for 36 m booms) is connected via a t-piece into the
cross over hose. The base of the left hand cylinder
is connected via hydraulic hose to the rod end of
the right hand cylinder. A second nitrogen charged
accumulator (70 bar for 36 m booms) is connected
via a t-piece into the other cross over hose.
If the boom yaws to the left, the right hand cylinder
will try to compress. This will push oil out of the base
of the right hand cylinder into the rod end of the
left hand cylinder also into the accumulator against
the precharge pressure (70 bar for 36 m booms).
Because the hydraulic yaw is a closed circuit the oil
movement is restricted by the precharge pressure
in the accumulator. This precharge pressure is what
resists the boom yaw movement and pushes it back
to the centered position. If the boom yaws to the
right the opposite action occurs.
The circuit precharge needs to be monitored and
maintained. Gauges on the centre section display the
closed loop hydraulic yaw pressure. This pressure
should be maintained at 100 bar.
NOTE: When the hydraulic yaw system is installed
or any components are replaced, the closed loop
hydraulic circuit needs to be bled of any air. The
maximum pressure needs to be set, the system
charged and the booms aligned.
BLEEDING YAW CIRCUIT
When the hydraulic yaw system is installed or any
components are replaced, the closed loop hydraulic
circuit needs to be bled of any air, the maximum
pressure set, system charged and the booms aligned.
1. Park the machine on a flat level surface, engage
the parking brake and chock the sprayer wheels.
2. Open the boom into the working position and
lower to the minimum working height. (Ensure
there is ample room in front and behind the
boom as it will be required to oscillate. )
Prairie Pro Operator's Manual MY19 - REV 2
t ent
3. Isolate the boom lift cylinders by rotating the
Paralift cylinder ball valves to the OFF position.
4. Remove the covers from the in-line test point on
the accumulators.
5. Connect the bleed hose (supplied in the sprayer
kit) to in-line test point on the accumulators.
6. Couple the bleed hose quick connect end to an
external hydraulic source, such as a tractor.
7. Using the external hydraulic source, oscillate the
boom back and forth ensuring to hold the boom
at its extremities for approximately 30 seconds
in each direction. Start by activating the hydraulic
source in one direction. The boom will oscillate
forward and stop when the hydraulic cylinder is
fully extended.
Hold the hydraulic supply in position for at least
30 seconds to ensure that the hydraulic cylinder
is fully extended. Move the hydraulic source in
the opposite direction until the opposite cylinder
is fully extended, again hold in position for 30
seconds to ensure the cylinder is fully extended.
Repeat this at least 15-20 times to bleed any air
from the system.
Continued over page
Chapter 9 - Boom -
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