I was recently contacted by a customer who processed grain seeds. From harvested wheat, he separates out the largest grains and processes them for next year’s seed. This is accomplished by screening.
The problem that he was having though, was the presence of a particular weed seed that was approximately the same size as the wheat and would not separate out. This compromised the quality of his seed stock.
Since this weed seed was considerably lighter than the wheat seed, I suggested he build a vibrating table positioned on a slant so that the seeds would progress to one edge of the table and free fall to a bin below. As the seeds were in their free fall state, position a model 110048, 48″ Super Air Knife blowing a laminar sheet of air through the downward falling stream of seed. This would redirect the lighter weed seed away from the heavier wheat seed.
Being resourceful as farmers are, he simply took a 4×8 sheet of plywood and mounted an electric motor to the bottom side. Then on the motor shaft he installed a metal disc with a hole drilled off center. This caused the plywood to vibrate. With a grain auger he poured enough grain to get a single layer falling over the edge. Then by adjusting the air pressure to the air knife, the right amount of force was achieved to blow the lighter weed seed away but not disturb the heavier wheat seed.
With a minimum investment, this customer was able to produce a superior grade of seed.