Blower Capacity
Page
120
05/06
The maximum allowable speed for
the blower is 4500 rpm. A restrictor plate
has been fitted to the flow control valve to
help prevent over running the blower. The
alarm on the monitor in the tractor has also
been set to activate if the speed runs over
the recommended maximum of 4500 rpm.
Constant over running of the blower
will reduce the life of the hydraulic motor
and possibly cause damage to the blower
impeller.
Blower Speed
The speed setting for the blower will
depend on the amount of material you wish
to convey. Blower speed is not critical to
the accuracy of the metering because of the
inbuilt pressure equalisation system that
exists on the Gason Air Seeder.
A more important factor when setting
the blower speed is to supply enough air to
reliably convey the product but not so much
that you produce seed bounce or product
damage at the sowing boot.
One method of checking fan speed is to
remove one of the tertiary hoses from a
sowing boot and hold it at chest height with
the end of the hose pointing up. With the
fan at operating speed have someone turn
the calibration handle over to simulate
ground speed, or activate the prime
function if VRT equipped, to send product
through the system. Material should exit
the hose and be projected approximately
300 to 500mm vertically beyond the hose
end.
NOTE:
All reference to blower speed refers
to operational speed while seeding. This
speed may vary from the blower speed set
when no material is being conveyed. It is
important to remember when setting the
blower speed to check the speed again
when actually seeding. This can be done
through the seeder’s monitor in the cab of
the tractor.
At low application rates the difference
between a stationary fan speed setting and
when actually seeding will vary little if at all.
However on some tractors it may be
impossible to obtain the high blower speeds
(4500rpm) required, when the application
rates are high, until the product is being
conveyed.
To obtain maximum fan speed, simply
set the flow control valve to maximum and
begin seeding. Once material is being
conveyed check fan speed on the monitor.
DO NOT EXCEED 4500 RPM BLOWER
SPEED. EXCESSIVE BLOWER SPEED
WILL REDUCE THE LIFE OF THE
HYDRAULIC MOTOR AND IMPELLER.
If when seeding, you find that the
blower is running too fast, stop the machine
and reduce the setting on your flow control
valve at the seeder (refer Fig. B2), or from
the tractor, if equipped with closed centre
hydraulics.
Determining the Appropriate Blower Speed
Blower speeds can be grouped into 4
different levels for material application.
A low total application rate will only
require a relatively low blower speed. As the
application rate increases, so too will need
for the blower speed to increase. Refer to
Table B3 for recommended speeds.
Very low application rate
3000 rpm
Low application rate
3800 rpm
Medium application rate
4100 rpm
High application rate
4500 rpm
Table B3 Blower Speed
To determine the appropriate speed for
the blower we must first determine the total
material application rate to be conveyed.
