Great Plains 3PYPA Operator Manual - Manual (Page 47)

Great Plains Manufacturing, Inc. Table of Contents Index Operating Instructions 43
03/20/2012 Table of Contents Index 401-647M
Air System Overview
The hydraulic fan supplies air for both seed delivery
and meter operation. Fan rpm is operator-adjusted
(page 45) via the tractor’s hydraulic flow control, and
reported by the seed monitor system. The rest of the
system is fully automatic.
At the split air manifold , a rotary actuator operates
a vane, under the control of software in the WSMT ,
which regulates the air diverted to the meter pressuriza-
tion system
.
Air not used for metering (typically just under half of it)
flows to the air box
for bulk seed delivery. The meter
pressurization air has priority, and can take all the air.
Several rows have lines to sample metering air pres-
sure, which is measured in a sensor chamber . The
sensor reading is fed back to the WSMT for
closed-loop pressure control. No operator adjustment is
required for the metering air system.
At the air box , air is mixed with seed from the bulk
hopper or ProBox, and flows out of the air box manifold
ports into primary seed hoses
to the rows. Y-tubes
(not shown) may split primary hoses into secondary
hoses to rows.
An air release screen above each Air-Pro
®
meter
vents the delivery air. The vent has two functions:
1. It releases delivery air while retaining the delivered
seeds.
2. It is a passive control gate for bulk seed delivery.
Note: It takes about a minute to initially fill the meters.
Separate pressurization tubes provide the air to the
meters that holds the seed in disk cells until released to
the seed tubes
.
A detector in each seed tube reports seed passage to
the seed monitor system, which reports counts and rates
on the console
.
There is a butterfly valve for the center section meter
pressurization air. This valve is calibrated at the factory
for your planter, and locked. Do not adjust it.
Null4:
Figure 49
Fan and Manifold
29882
There are console menus for adjustment of metering air,
and manual fall-back modes.
In the case of insufficient fan air, or significant seed
delivery air leaks, seed flow may be irregular or stop.
Meter Pressurization is displayed by a mechanical
gauge, and by sensors connected to the seed monitor
system. As these sensors measure pressure at similar
locations, they generally agree.
If seed delivery air flow is insufficient, the indication will
be low seed rate alarms. If fan speed and direction are
as recommended, check for air leaks in the seed deliv-
ery system.
When the meter inlet is filled, and seed fills the tube
above the inlet, the screen becomes blocked by seed,
shutting off air flow to that meter. As the meter con-
sumes seed, the screen becomes exposed, air resumes
flowing, carrying more seed from the air box manifold to
the meter.
Several rows have pressure sensor ports for the meter
pressurization system. Use of the special blank disk is
particularly important when one of these rows is shut
off. Running a normal disk with no seed causes the air
system to over-compensate.
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