Our aim is to improve the function, safety and durability, of the existing root washer tool we surveyed at the Farm Hack Intervale meet up. We would also like to reduce the up front cost. We were very lucky to have input from the farmers who use this washer on a regular basis and at high volume. The improvements we propose fit into a few basic categories.
1 Materials The materials used for construction of the main barrel in the existing iteration are wood and formed steel-channel rings. Fabrication of the rings is one of the main expenses adding to the cost. They serve as the tracks into which casters fit and as the main support structure. One suggestion was the use of bicycle rims for this purpose. One concern about this solution was that they would be to small. We were told by the farmers that the wood slats of the barrel wore down and needed replacement. Talk about alternatives to wood led to the idea of using a piece of culvert pipe. If this could be sourced cheaply or salvaged, it could solve both issues at once.
2_Drive Mechanism_ Currently a chain is used to rotate the barrel with protruding bolts serving as gear teeth. In the second iteration, a gear box was added allowing for two speeds and the elimination of a pulley and v-belt used to gear down the motor. Occasionally the chain will jam on the teeth, lifting the whole barrel up and dropping it back down on the casters. This created a safety issue. There was talk of using a toothed timing belt, or fabricating gear teeth rather than using bolts. It seems the best way to go would be a pneumatic drive wheel(s) in place of the casters. This would eliminate issues with the chain and have the advantage of increased friction with increased load, avoiding slipping under heavier loads. Perhaps the flange of the culvert pipe could keep it in place over the drive wheels instead of casters/channel?
3_Work Flow_ Last year a hopper was added with a winch to lift it. The goal was to ease loading and control feed speed. This did not work out as planned and may interrupt work flow and could be dangerous. A hopper with a conveyor belt may be a better option. At times farmers wanted to stop the flow of roots coming out of the washer or just wanted them to stay in longer to wash more. A gate was tried, or farmers would push the roots back up the barrel by hand. The ability to change the angle of the barrel could change the speed that roots exit, or stop them from coming out to wash them longer. A re-purposed jack under the frame could quickly change the angle.
4_Silt_ To do a better job cleaning the roots, bristles could be added to the inside. If they were arranged in a helical pattern they could help advance roots like carrots. Silt must be managed so it doesn't clog drains or gravel. A perforated pipe like the ones used in a french drain could drain water from a catchment where silt can settle. The idea of recycling water was put forward. The problem cited was food security.