A seed fractionator operates by subjecting seed to a tortuous air stream of finely adjustable speed. The seed sample is separated into light seed and heavy seed. The fractionation can be done several times to subdivide a sample into more parts. Germination tests performed on each sample allow the seed seller to certify the germination rate.
This seed fractionator is powered by an electric shop vacuum, which supplies a steady flow of air.
These plans were developed by Ben of the RealSeeds company in England, http://www.realseeds.co.uk/
