Clinker cooler

A conveyor floor configured to convey cement clinker in a conveying direction from a material inlet to a material outlet, the conveyor floor comprising:

• longitudinal planks, each with a corresponding up-facing surface configured as a rest for the cement clinker, said planks extending parallel to the conveying direction and transversely to the conveying direction one besides another with moving gaps in between,
• a support structure configured to support and reciprocate at least some of said planks, to thereby convey the cement clinker in the conveying direction,
• wherein:
• each plank has a mean coefficient of friction Cf, associated with movement of the cement clinker in the conveying direction relative to the respective plank, and a mean coefficient of friction Cb associated with movement of the cement clinker against the conveying direction relative to the respective plank;
• at least one of said planks has on its up facing surface at least one protrusion, said protrusion having a front facing side and rear facing side, wherein a mean slope of the front facing side is steeper than a mean slope of the rear facing side;
• a relation Cb/Cf≧1.5 holds for at least a majority of said planks and a height h of said protrusion is smaller than a mean diameter of the cement clinker grain;
• and
• the planks are grouped in exactly two groups of planks, wherein planks forming a first group of planks are driven to reciprocate in parallel to their longitudinal axes and planks of a second group of planks are mounted to a static support structure.