CS254700B1 - The grate of Huid's boiler - Google Patents

Abstract

The essence of the solution lies in the fact that the cooled pipes fixed by ridges are bridged by continuous bombed steel strips, equipped with transverse grooves, while the transverse grooves are covered by segments of the rectifiers.

Description

BACKGROUND OF THE INVENTION The present invention relates to the field of fluidized bed steam boilers and solves the construction of a fluidized bed boiler. Fluid grate structures are known. The most well-known and most commonly used (mainly abroad) is the fluidized grate, which is made in various modifications, which makes it possible to create an insulating stagnant layer and its construction is suitable mainly for single-stage fluidized bed combustion. For the two-stage combustion, for example, a fluidized-bed grid according to Czechoslovakian AO 2 141129 was constructed, where the fluidized bed consists of cooled pipes and inserted perforated angles, or a construction according to Swiss Patent No. 36,942, where the own grate is formed by a membrane wall with openings in the filling flat bars.

For combustion by higher fluidization rates, for example in fluidized-bed fluidized bed boilers and also in two-stage combustion, the cap grate is unsuitable because the caps do not allow for a sufficient fluidizing air cross section. In the case of the fluidized bed according to the Czechoslovak AO 2 141129 and the like, the non-leakage of the fluidized bed particles under the grate is not ensured and the pipes of the fluidized bed are eroded. Although the fluidized bed construction of Swiss Patent No. 636,942 prevents the falling of the fluidized bed particles, the unfavorable pipe erosion factor is the same as in the previous case and, in addition, the thermal load in the absence of an insulating stagnant layer achieves unacceptable values for larger rods. All of the aforementioned drawbacks are eliminated by the grid of the fluidized-bed boiler according to the invention, characterized in that the cooled grate tubes fixed in precise spacing by welded ridges are bridged with continuous crowned steel strips provided with transverse grooves. The continuous crowned steel strips are reinforced by flat bars in the area between the transverse grooves in the longitudinal axis, on which only the deflection segments overlapping the transverse grooves are welded on one side. The advantage of this solution is that the transverse grooves formed over almost the entire width of the continuous crowned steel strips compensate for the longitudinal dilatation differences resulting from the rough temperature of the steel strips and the cooled tubes, thereby eliminating the causes of tension and subsequent possible deformations. By crowning the continuous steel strips, their compensating ability in the transverse direction is increased with the dilatation differences between the welded comb and the continuous steel strip. The grate construction also ensures that the fluidized bed particles below the grate are not obstructed and the cooled pipes are protected from erosion by the fluidized bed particles.

1 shows a cross-sectional view of the grate, FIG. 2 is a plan view, and FIG. 3 is a side elevation of the grate.

The cold tubes 1 are provided with a welded ridge 2 at the desired exact spacing. The adjacent chilled tubes 1 are bridged by continuous crowned steel strips 4, which are in calculated longitudinal spacing, with transverse grooves 3. The baffle segments 5 overlapping the transverse grooves 3 are welded on flat bars 6 which are disposed in a longitudinal axis of the continuous crowned steel strips 4 in the area between the transverse grooves 3.

The fluidizing air supplied under the grate exits through the baffle segments 5 through the transverse grooves 3 and causes the fluidized bed of the fluidized bed process. When the fluidizing air is shut down, the baffle segments 5 prevent the fluidized bed particles from falling under the grate. By bridging the cooled tubes 1 through the continuous crowned steel strips 4, the erosion of the cooled tubes 1 by the fluidized bed particles is prevented.

The invention can be used for all types of fluidized hearths, and it is particularly advantageous for fluidized bed furnaces with two-stage combustion.

Claims (2)

SUBJECT Fluidized bed boiler grate with refrigerated tubes fixed to a precise distance by means of welded ridges, characterized in that the refrigerated tubes (1j) are bridged to each other by continuous grooved steel strips (4) provided with transverse grooves (3j), wherein the continuous grooved steel strips (4) they are reinforced in the area between the transverse grooves (3) by flat bars (6) in the invention of the longitudinal axis, to which the rectifying segments (5) overlapping the transverse grooves (3) are welded on only one side. 2. A fluidized bed boiler as set forth in claim 1, characterized in that the continuous grinded steel strips (4) are welded together with the cooled tubes (11) which fully overlap them.