Gravity

Have I told you how seed cleaning is the hardest part of being a grain farmer? It's the biggest barrier between the farm and market. Imagine you dropped a sack of multi-sized marbles on a pile of round rocks, then they got mixed together. How would you separate them? You could put them through a screen, but some of the rocks are the same size as the marbles. The marbles aren't the same size, so you might keep some and lose others. That's like seed cleaning. Grains with weed seeds of the same size and shape.One stage of cleaning, with the air screen cleaner, material can be separated by size and somewhat by weight. The very light material, usually chaff, get blown off. But, if the detritus and grains are the same size and approximate weight, then another mechanism is required.Enter the gravity table. The gravity table holds up a vibrating surface that separates material by density. Brilliant! Too bad they're very expensive new ($20,000) and hard to find used (took us 2 years). Our equipment co-op finally got one, but it's the wrong motor phase! So, I was a human gravity table last night for 2 hours, shaking through 5 pounds of grain on a cookie sheet. Yet, I need to send off a grain sample to a customer. Here's to hoping we get the motor and convert it soon.