Great Plains YP925TD Operator Manual - Manual (Page 33)

Great Plains Manufacturing, Inc. Table of Contents Index Operating Instructions 29
02/23/2011 Table of Contents Index 401-755M
Air and Seeding System Overview
Refer to Figure 19, on page 28, and Figure 20.
The hydraulic fan
supplies air exclusively for meter
operation. Fan rpm is operator-adjusted (page 31),
normally via the tractor circuit’s hydraulic flow control.
A manually-adjusted butterfly valve is provided at the
fan outlet. See page 31 for valve adjustment.
The manifold system delivers fan air across the
planter. It includes passive internal design features to
balance pressure across the planter.
Separate pressurization tubes route manifold air to
each row unit.
Seed is delivered from the seed box by gravity
through the sliding seed tubes , to the inlet of the
Air-Pro ® seed meter .
A manually adjusted inlet shutter controls the size of
the seed pool at the base of the meter. The shutter
also minimizes air loss up the seed inlet tube, and is
used during row shut off. See page 57 for shutter
adjustments.
At the meter, pressurization air exits the meter through
the seed pockets
of the disk, and holds seed in the
pockets until released above the seed tube .
In the seed tube, the seed sensor detects passage of
seeds. Medium size and large seeds are counted
individually. With smaller seeds, most are detected,
allowing the monitor to detect stoppages.
Several rows have a pressure sensor port for the
meter pressurization system. A line from each of
these rows is connected to a chamber to average the
pressures.
The averaged pressure is reported by a Magnehelic ®a
gauge visible to the tractor operator. See page 42 for
use of the gauge in making fan adjustments.
A sensor in each seed tube reports seed passage to
the seed monitor. Larger seeds are counted individually.
For smaller seeds, the system detects blockage.
Note: Use of the special blank disk (page 61), and closing
the seed inlet shutter (page 57), are particularly
important when a sensor row is shut off.
Note: On any row, running a normal disk with no seed, or
with an open empty inlet, unbalances the air
system. Doing either at a sensor row causes the
gauge to mis-report as well.
a. Magnehelic ® is a registered trademark of Dwyer Instruments, Inc.
Note: Do not operate in the ground with the fan shut off,
or with insufficient manifold pressure. The meters
will completely fill with seed. Meter clean-out may
be required to resume normal operation.
Figure 20
Air-Pro ® Meter, Disk Side
31040
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