Other round bar concaves work well in that they rarely ever plug, and therefore can be “universally” used across crops and conditions, but the rotor loss and grain damage in corn is unacceptable. Our patented RPR Concave System is the best of all worlds, no plugging, no rotor loss, less broken cobs, less fines, more capacity and significantly better sample from running a slower rotor speed.
Every rotor loses between 2-5 bushels / acre at $4 corn that’s $20k per 1000 acres. Just leaving eight or nine kernels per square foot behind the combine translates into 1 bu. of corn lost per acre. Our round-bar concaves STOPS all rotor loss, improves thresh, reduces splits and makes for a cleaner grain sample.
The Estes notched round bar, “Pacman Bar” is what forces material to rub on material causing thrashing. The only way to get a good thrash from a round bar concave is to keep the concave full, forcing the material to rub on material.
We are Progressively open because thrashing immediately happens on the entrance to the concave section and the Progressively Open bars help unload the concave quicker. Our “Pacman Bars” go from 7/8” to 1 1/8” as crop is moving through the concave section. Our purpose is to get crop out of the front section sooner so that less is needed to be thrashed toward the back of the cleaning system, and no crop is going out the back of the machine.
The round bars on the Estes RPR thrashing/separating system were used only to prevent corn shuck plugging but the restricted flow notch is what forces the thrash and the progressive open spacing is what lets the thrashed crop out stopping rotor loss.