Grate bar for stepped grate

A grate bar rear section configured for being mounted to a grate bar front section, in order to form by such mounting a grate bar,

• wherein the grate bar rear section has a middle part, a first side element, and a second side element,
• wherein:
• the middle part has at least a first leg and a second leg, wherein the first leg and the second leg form an angle profile,
• the first leg has at least one through hole, and
• the middle part has two longitudinal sides and on each side of the two longitudinal sides of the middle part one of the first and second side elements is attached, respectively, and the middle part has a third leg,
• the second leg and the third leg point in opposite directions and axes of the second and third legs form an angle with a value within ±30°, wherein the first leg is the middle leg.

A grate bar front section configured to be mounted to a grate bar rear section to form by such mounting a grate bar,

• wherein:
• the grate bar front section includes a refractory mineral material and a top side, a bottom side, a front side, two narrow sides, and a rear side as well as a grate bar longitudinal axis that extends parallel to the top side through the front side and the rear side,
• wherein:
• the grate bar front section includes a recess that extends from the bottom side in a direction of the top side,
• the recess has at least one contact surface configured to introduce a force acting in a direction of the rear side and/or the front side into the grate bar front section, and
• the grate bar front section includes at least one channel with a channel longitudinal axis, the at least one channel connecting the rear side and/or the front side and/or at least one side surface with the recess, the grate bar front section further comprising at least one gas passage that extends from the bottom side in the direction to the top side and/or in a direction to the front side,
• wherein the at least one gas passage has an inlet in the bottom side and an outlet in the top side and/or the front side,
• wherein the at least one gas passage is curved towards the front side at least in a region adjacent to the top side, the top side and a tangent forming an acute angle,
• wherein the tangent is defined at a point of a lower side of the at least one gas passage a region adjacent to the top side, and
• wherein a value of the acute angle decreases as a distance between said point and the outlet is decreasing.

A grate bar front section configured for being mounted to a grate bar rear section, in order to form by such mounting a grate bar,

• wherein the grate bar front section includes a refractory mineral material and a top side, a bottom side, a front side, two narrow sides, and a rear side as well as a grate bar longitudinal axis that extends parallel to the top side through the front side and the rear side,
• wherein:
• the grate bar front section includes a recess that extends from the bottom side in a direction of the top side,
• the recess has at least one contact surface configured to introduce a force acting in a direction of the rear side and/or the front side into the grate bar front section,
• the grate bar front section includes at least one channel with a channel longitudinal axis, the at least one channel connecting the rear side and/or the front side with the recess,
• the grate bar front section comprising at least one gas passage that extends from the bottom side in the direction to the top side and/or the front side,
• wherein the at least one gas passage has an inlet in the bottom side and an outlet in the top side and/or the front side, and
• wherein the at least one gas passage has a longitudinal axis that forms an acute angle with the top side or the front side.