Grate block for a combustion grate

A grate block for a combustion grate, in which successive grate blocks are disposed one on top of one another in the manner of steps and are designed in such a manner that the incinerator charge is shifted and conveyed during the combustion by means of thrust movements performed relative to one another, wherein the grate block has a block body which has an upper wall and defines a longitudinal axis L, wherein the upper wall forms a bearing face along which the incinerator charge is to be conveyed and the foremost end thereof, when viewed in a thrust direction S aligned substantially parallel to the longitudinal axis L forms an edge by way of which the bearing face descends into a thrust face formed by a front wall, the front wall has first air supply openings which are in each case formed by a first air supply duct for supplying air onto the combustion grate that, when viewed in the longitudinal section, runs orthogonally or obliquely to the thrust face, and has a lower bearing edge which is disposed in a plane E running substantially orthogonally to the longitudinal axis L and is specified for coming into contact with the bearing face of a grate block adjacent in the thrust direction S, characterized by further air supply ducts for cooling the upper wall and the front wall that extend through the upper wall and the front wall and are aligned obliquely to the direction of the first air supply ducts, wherein the further air supply ducts, when viewed in the longitudinal section, run at an angle β to the longitudinal axis L of the block body, where β is from 10° to 60°.