Cleaning Seeds With an Aspirator
How to Build and Use an Aspirator
Seed Purity Is
•
•
•
•
How much of a seed lot is pure seed
Weight of pure seeds ÷ total weight of seeds
Raised when trash is removed
An important measure in managing seeds
– Test for weeds and other species more easily, at
less cost
– Pure seeds are more accurately sown and
germinated
– Reduce storage volume, more seeds fit in freezer
What An Air Cleaner Does
• Seed lots with trash lighter than the seeds (or
heavier than the seeds) can be cleaned (raised
in purity)
• Seeds are fed into an upward moving column
of air where the light particles are lifted into a
settling chamber and heavy partitcles fall to
the bottom of the air column
Aspirator: An
air cleaner
using vacuum
to remove light
trash from
seeds
Funnel to feed
seeds into
drop tube
below air
exhaust
Control ports to adjust
vacuum, cover with
something to increase
vacuum in seed drop
tube
Seed
drop
tube
made
from
drink
bottle
Two inch
electric conduit
connector
Seed aspirator made from
repurposed parts
2x1½
inch
adapter,
seems to
fit most
vacuum
inlets
Set up for very light seeds
Extra port to
bleed off
additiional
vacuum for
very light seeds
Shop
vacuum
Stock pot
settling
chamber
Vacuum control ports
Under side of the stock pot cover
Female adaptor
screwed on to conduit
connector
45 elbow to defect light
particles to bottom of
settling chamber (stock
pot)
Adjusting the Aspirator
• Seeds are fed in a narrow uniform stream on
to the side of the funnel and into the seed
drop tube
• The control ports are gradually closed until the
desired amount of trash is removed
– Seeds fall down the seed drop tube
– Trash goes to the settling chamber
– A few good seeds lost for maximum trash removal
Heavier good
seeds
Insect hole
Lighter insect
damaged seeds
Lomatium seeds separated in the column blower
Separating Weeviled Seeds From
Whole Seeds With Lomatium spp
• At first glance it looks easy because there are
holes straight through the bad seeds
• But removing the bad seeds does not work
– To remove most of the bad seeds, many goods
seeds are also removed
– To leave most good seeds in the lot, many bad
seeds remain
– Why not if I have good equipment?
Sizing Seeds First
• The Lomatium seeds were sized with round
hole screens: 16, 18 (bigger number large
diameter hole)
• Then each size cleaned separately in the
aspirator and an excellent separation of good
and bad seeds was obtained
• Next slide shows the reason for this result is
that smaller (16) diameter good seeds weigh
what larger (18 ) diameter bad seeds do
LODI 26
Individual seed weight
Larger diameter light (18L) (bad) seeds weigh the same
as smaller diameter heavy (16H) (good) seed
0.03
0.025
16H
0.02
16L
0.015
18H
0.01
18L
0.005
0
1
2
3
4
5
6
7
Individual seed number
8
9
10
Why it is necessary to size
Seed to remove lighter
damaged seed
How Clean Do I need the Seed?
• For genetic conservation: close to 100% pure
• For automated sowing in containers: close to
100% pure
• Sometimes answer is not clear, weigh different
needs against cost of extra cleaning
– Is the lot clean enough to sample and test
accurately?
– Will the seed flow through seeders?
– Will the customer pay for extra purity?
Quality Seed Does Not
Cost, It Pays