Dave Pennington and I have need to sort rock sizes from a gravel pile, for use in our fill and drain Aquaponics system. Seems this is an overlooked area that is a lot of manual labor. Your choices are to buy expensive presorted stone like “rainbow” rock or clay beads (Hydroton), or to sort and clean it yourself. Dave already has a customized concrete mixer that is a dedicated gravel washer, so washing gravel is much easier.
Dave found the motor and springs for the rock sorter, and I cobbled together the rest. The motor is from an old paint shaker mixer. It is just 1/12th horsepower so it is more of a vibrate than a shaker.
The design is supposed to shake rocks shoveled into the top and sort the large stones out one end.
The stones 7/8″ or less fall through the first tray into the second tray that is a 1/2″ screen. Rocks and dirt smaller than that fall into the yet to be built 3″ tall tray at ground level. The rock size we want should also roll (shake) out the end into a separate, shorter bucket.
The trays can be raised to level or one of 5 settings of tilt up to 4″ on the outgoing end. Also, the sorting sizes can be changed by changing out the screen on the trays, with a few screws.
The unit is 2′ by 3′ by 26″ tall where you shovel in the rocks. The top of the motor is at 33″. It should be short enough to ease shoveling in the rocks and small and light enough to transport easily.
The motor mount is hinged by loosening a couple bolts, should better access to the “wobble-later” be required.
I still need to add output trays, make a short bucket to catch the rocks from tray two and perhaps add wheels.
We will see how well it works. We may need a more violent shaker motor.
Below are first pictures of our design. Click to see the larger pictures.