Apparatus for mixing bulk materials in dust, powder or coarse grained form

Device for blending dust, powder or coarse particle bulk materials, comprising a first upper blending device with a cylindrical blending container and a connecting upper discharge funnel tapering conically towards a second lower blending device with a cylindrical container and a connecting discharge hopper which tapers conically towards the bottom to form an upper and lower mass flow silo, a blending pipe concentrically installed in the upper blending device for mass flow, which extends approximately to the lower end of the upper connecting discharge funnel, whereby the blending pipe contains inlet openings throughout its whole length for bulk material;

• and wherein:
• the concentrically installed blending pipe is vertically subdivided into numerous gravity pipes arranged side by side, each of which contains several inlet openings arranged above one another, said blending pipe is constructed cylindrically in the lower end region;
• and means are provided for transporting the bulk material situated at the lower end of the lower blender device back to the upper material surface of the device via a conveying pipe.