Abstract: A cooler for cooling particulate material which has been subjected to heat treatment in an industrial kiln, such as a rotary kiln for manufacturing cement clinker, which cooler comprises an inlet, an outlet, end walls, side walls, a bottom and a ceiling, at least one stationary supporting surface for receiving and supporting the material to be cooled, means for injecting cooling gas into the material, as well as a reciprocating scraper system which comprises a number of rows of scraper elements arranged transversely across the direction of movement of the material, said scraper elements being moved back and forth in the direction of movement of the material for conveying the material forward across the supporting surface.