Meterbox Assembly - General
Page
114
12/09
Introduction
The hydraulic motor that drives the air
seeder blower is a robust and highly
efficient unit. It has been chosen because
of its ability to operate at high speeds for
extended periods.
The hydraulic circuit has also been
designed to operate for extended periods
with minimal maintenance. The only
component
that
will
require
regular
maintenance is the high capacity oil filter.
Refer
to
the
hydraulic
filter
maintenance
section
for
servicing
information (page 117).
Flow Control Valve
A flow control valve is located near the
fan. The valve can be used to adjust the
fan’s speed and will protect the motor
against excess flow from the tractor. The
valve will also protect the system from
incorrect direction of flow in case the hoses
are connected in reverse.
Fig.H1 Hydraulic layout sketch.
Tractor Requirements
A standard tractors hydraulic system
in good working order with a cooling system
is all that will be required to run the Air
Seeder. In most cases no modification will
be necessary other than having 2 hoses
fitted directly to the tractor’s hydraulic
reservoir for return flow.
The flow required to operate the air seeder
will vary depending on the specific model
and options.
Refer to table H2 to determine the flow
requirement for the particular model air
seeder. The tractor will need to obtain this
flow at 160 bar (2350 psi) to achieve the
indicated fan speed when conveying
product.
Ground Drive
VRT Hyd. Drive
FAN RPM
4000
4500
4000
4500
L / MIN
48
54
68
75
GPM (US)
12.7
14.3
18
19.8
Table H2 6 Outlet Meterbox hyd. requirement.
Open Centre Tractor Hydraulics
It is preferable to have a slightly higher
flow rate going to the seeder’s system when
the tractor is equipped with open centre
hydraulics. This slight excess will help
maintain constant fan speed and reduce the
risk of material blockages in the distribution
system.
Control the required fan speed at the
seeder using the flow control valve (fig.H3).
Closed Centre Tractor Hydraulics
Some closed centre hydraulic systems
that compensate pressure and flow will
require a specific set-up procedure to
control the fan speed and to eliminate
possible fluctuations in fan speed.
It is necessary to control the fan
speed from the tractor instead of the flow
control valve on the seeder.
Use a set of remotes on the
tractor that has some form of control device
fitted as standard. Set the seeder flow
control valve to its maximum position,
against the stop, and lock into place.
