The safety of the firing grate
The object underlying the invention is achieved by a water-cooled fire grate , which consists of a plurality of blocks of grate bars extending over the width of the grate, each block consisting of multiple grate bars, wherein each grate bar has a meander-shaped channel in addition to several cut-in grate slots inside. The grate bars are furthermore connected with each other by screwable connecting pieces such that a grate slot is formed between two grate bars. In the interior of the connecting pieces a connecting passage extends, which connects the meander-shaped channels of two grate bars. The grate bars positioned on the boundaries of the grate have screwable inlet and outlet pieces, through which the liquid coolant water is supplied and discharged.
Because of the cooling of the grate with the liquid coolant water, the temperature at the surface of the travelling grate bar is 90 to 110° C. The result is a reduction of the wear of the grate and the grate has a high thermal load-bearing capacity of 0.9 to 1.1 MW/m 2 grate area. This leads to the fact that the inventive grate can be built smaller by about 30% as compared to the known air-cooled grates with the same thermal efficiency. The meander-shaped design of the channels arranged in the interior of the grate bars, through which flows the coolant, and the connecting, inlet and outlet pieces to be used in accordance with the invention advantageously cooperate such that the supply and discharge of the coolant is only effected from the boundaries of the grate. The individual blocks of grate bars or several blocks of grate bars can thus be provided with the coolant at the boundaries of the grate, so that the operational safety is increased. The connecting pieces ensure that between the individual grate bars, of which a block of grate bars consists, grate slots are formed, which do not change their width during the operation. This high dimensional accuracy of the inventive travelling grates ensure both a minor passage of ash through the grate and an optimum supply with combustion air and a substantial burn-out of the fuel on the grate, so that finally a high thermal load is achieved.
In accordance with the invention it is furthermore provided the connecting, inlet and outlet pieces enclose a grate bar carrier and are screwed to the carrier. The meander-shaped channels of the grate bars are connected with each other via the connecting passages of the connecting pieces. The dimensional accuracy of the blocks of grate bars and the operational safety of the firing grate are thus increased.
Because of the cooling of the grate with the liquid coolant water, the temperature at the surface of the travelling grate bar is 90 to 110° C. The result is a reduction of the wear of the grate and the grate has a high thermal load-bearing capacity of 0.9 to 1.1 MW/m 2 grate area. This leads to the fact that the inventive grate can be built smaller by about 30% as compared to the known air-cooled grates with the same thermal efficiency. The meander-shaped design of the channels arranged in the interior of the grate bars, through which flows the coolant, and the connecting, inlet and outlet pieces to be used in accordance with the invention advantageously cooperate such that the supply and discharge of the coolant is only effected from the boundaries of the grate. The individual blocks of grate bars or several blocks of grate bars can thus be provided with the coolant at the boundaries of the grate, so that the operational safety is increased. The connecting pieces ensure that between the individual grate bars, of which a block of grate bars consists, grate slots are formed, which do not change their width during the operation. This high dimensional accuracy of the inventive travelling grates ensure both a minor passage of ash through the grate and an optimum supply with combustion air and a substantial burn-out of the fuel on the grate, so that finally a high thermal load is achieved.
In accordance with the invention it is furthermore provided the connecting, inlet and outlet pieces enclose a grate bar carrier and are screwed to the carrier. The meander-shaped channels of the grate bars are connected with each other via the connecting passages of the connecting pieces. The dimensional accuracy of the blocks of grate bars and the operational safety of the firing grate are thus increased.
