US Patent 7270469 Apparatus and method for adding pigmentation to concrete mix

A pigmentation dispenser utilizes a hopper having two rotors therein, a first rotor above a second rotor. The second rotor moves the pigmentation material through an outlet opening and deposits it on a conveyor containing a concrete mix. The concrete mix and pigmentation material are then moved to a mixer which mixes them together. A cleanout is also in communication with the hopper and the second rotor can be reversed to move the pigmentation toward the cleanout.