Among the piles of screens, sieves, fans and motorized contraptions that we’ve cobbled together over the years to clean seed on our farm, the aspirator seed cleaner we built based on Real Seeds open source plans (https://www.realseeds.co.uk/seedcleaner.html) is one of the more efficient and versatile processing tools at our disposal for dry seeds. A vacuum pulls air upward through the vertical box where the raw seed and chaff are introduced. The lighter bits of leaf and plant material get blown upward and out into a chaff collector, separating them from the denser seeds, which continue their way down the shaft and into a collection tub at the bottom.
Aside from the Lexan front plate purchased new for the project, I built our seed cleaner out of scraps lying around the barn. I run it using a small household vacuum rescued from the dump. The only major change I made to the original plans was to cut a hole in the back of the apparatus that can be incrementally opened or closed to modulate the strength of the vacuum suction. This refinement allows us to extend the range of the machine to process many of the smaller, lighter herb and flower seeds that we grow. When we need extra power for high-grading especially heavy seeds, we use a stronger Shop-Vac motor.
– Daniel MacPhee