The Coperion K-Tron ProBlend zone blender homogenizes or blends free-flowing bulk material within a hopper or silo, while allowing different zones of material to discharge at different rates. Containing no moving parts, the unit uses a combination of mass flow (first in - first out) and funnel flow (last in - last out) in recirculating, batch or continuous systems, or any application requiring the blending of materials. The blender is suitable for 4-ft to 12-ft diameter silos or hoppers.