Abstract: A fire grate has tensioning devices (3) inserted in recesses (2) of an oven wall (1), with each device acting upon one grate side plate. The tensioning device (3) includes a cylinder (4) inserted into the oven wall, a hollow piston (7) guided therein and a spring (26), which can be adjusted in its tension. The grate side plate has a carrying plate (12) directly fastened to the piston bottom (10) with a grate border plate (13) suspended, or hanging, on the carrying plate (12). The piston (7) has diameter and length dimensions such that it can support and guide the grate side plate without further guiding devices. Neighboring pistons (7) are connected flexibly to each other by guiding bars (36), so that the pistons (7) can influence each other reciprocally. An upper edge of the grate side plate, particularly the grate border plate (13), has a flange (17) extending toward the oven wall. The flange (17) sealingly engages an elastical seal (19), fastened onto the oven wall.

Abstract: A combustion chamber is arranged above a burner grate, and a fragmentizing device fragmentizes refuse and forwards it to the combustion chamber in form a mix composed of lighter and heavier refuse particles. The lighter refuse particles become combusted in the combustion chamber whereas the heavier refuse particles drop out of the combustion chamber through an opening of the same and become deposited on the burner grate where they themselves become combusted.

Abstract: A combustion chamber has a lower end provided with a grate, and an inlet admits unclassified refuse into a comminutor wherein it is comminuted and forms a heavier particle fraction and a lighter particle fraction. The fraction having the heavier particles is directly admitted onto the grate, whereas the fraction having the smaller and lighter particles is subjected to a second comminution to convert the smaller particles into fine particles which are then admitted, either directly or indirectly, into the combustion chamber upwardly of the grate so that they become incinerated in the combustion chamber while floating therein. A method of incinerating refuse is also disclosed.