The grate includes a number of grate lanes arranged side by side between a left and a right side section, neighbouring lanes being connected by a midsection and including a lane section having a number of pivotal grate shafts carrying grate bars. Each midsection includes an upper relatively narrow housing section arranged between grate bars of neighbouring lanes and a lower relatively broad housing section protruding under grate bars of said lanes. The upper housing section of each midsection encloses bearings for grate shaft ends of neighbouring lanes. At least one midsection includes a drive mechanism for pivoting back and forth neighbouring grate shafts in opposite rotational directions and a synchronising mechanism of at least one lane section. An actuator of said drive mechanism and said synchronising mechanism are located in the lower housing section of said midsection.

Slag (28) is formed during the combustion of solid fuels with a lower ash fusion temperature and covers parts of the solid fuel, prevents complete combustion and blocks the air supply, thereby leading to an interruption of the combustion process. According to the invention, the embers and the fusing ashes are mixed by means of a cleaning comb (22) and are discharged from the burner. The burner consists of rotating grate bars (25) which are arranged parallel to one another within the inner walls (1). The cleaning comb (22) moves between the grate bars (25); upwards between the grate bars (25); in direction of the burner opening; downwards under the grate bars; and finally in the direction of the burner flange (7). When the slag (28) adheres to the rotating grate bars (25), it is scraped off by the cleaning comb (22). The fuel supplied to a funnel (8) slides downwards by the force of gravity, the funnel lid (9) opens, and the fuel is pushed onto the grate bars (25) by the plunger (11). The plunger (11) has at least one opening (15) for secondary air (5) which also provides cooling. A blower (13) blows the ashes fallen through the grate bars (25) through a cut-out section in the burner floor (30) opened by the floor trap (20).

Slag (28) is formed during the combustion of solid fuels with a lower ash fusion temperature and covers parts of the solid fuel, prevents complete combustion and blocks the air supply, thereby leading to an interruption of the combustion process. According to the invention, the embers and the fusing ashes are mixed by means of a cleaning comb (22) and are discharged from the burner. The burner consists of rotating grate bars (25) which are arranged parallel to one another within the inner walls (1). The cleaning comb (22) moves between the grate bars (25); upwards between the grate bars (25); in direction of the burner opening; downwards under the grate bars; and finally in the direction of the burner flange (7). When the slag (28) adheres to the rotating grate bars (25), it is scraped off by the cleaning comb (22). The fuel supplied to a funnel (8) slides downwards by the force of gravity, the funnel lid (9) opens, and the fuel is pushed onto the grate bars (25) by the plunger (11). The plunger (11) has at least one opening (15) for secondary air (5) which also provides cooling. A blower (13) blows the ashes fallen through the grate bars (25) through a cut-out section in the burner floor (30) opened by the floor trap (20).