Large seed grains partly have poor
trickling characteristics and thus do not
ll the roller utes completely.
In such cases talcum powder or graph-
ite powder may be added to the seed.
¾ When using the adapter frame you must install
and adjust the wider sealing lip - see adjusting
the sealing lip.
¾ The special rotors for coarse seeds should in
this case be used.
These are available in different sizes to
match the dierent working widths and seed
quantities.
Metering unit with Venturi-
type injector
The metering units in machines with normal
hopper and Venturi-type injector are equipped
with a V2A-cover with machined recesses.
During operation the injector nozzle is exposed
to vacuum. This V2A-cover adds additional air
to the air ow.
Metering unit with cover for injector nozzle
The adjustment between injector nozzle and
cover works up to a max. possible seed quantity.
Exceeding this quantity results in a dynamic
pressure at the injector nozzle. This may blow
seed out through the perforated plate, which
leads to a strip-like emerging of the seeds.
These grains are visible on the surface of the
eld before they are covered by the packer or
the harrow.
70
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