Combustion grate

Abstract

A grate (1) for furnaces comprises grate bars (5, 6, 8, 9) and grate rods (4, 7) engaging in receptacles (3) of grate bars (5, 6, 8, 9), by which grate bars (5, 6, 8, 9) can be moved back and forth in the direction of their longitudinal extent. Adjacent grate bars (5, 6, 8, 9) are moved relative to each other by pivoting movements during the back-and-forth movement in order to clean the air gaps between grate bars (5, 6, 8, 9). The direction of the relative movement between adjacent grate bars (5, 6, 8, 9) is essentially horizontal, parallel to the longitudinal extent of the grate bars (5, 6), and essentially perpendicular, due to pivoting movements of the grate bars (8, 9) transverse to the longitudinal extent of the grate bars (8, 9).

Description

[0001] The invention relates to a method for cleaning grates of furnaces on the one hand and a grate for carrying out the method for cleaning grates on the other.

[0002] Grates for furnaces are known to have several grate bars that sit on grate bars with downward-facing receptacles, which extend essentially transversely to the longitudinal extent of the grate bars.

[0003] The ends of the grate bars furthest from the recesses in the grate bars rest on grate bars adjoining those grate bars in the area of ​​the ends having the recesses for grate bars, so that the grate bars successive in the longitudinal direction of the grate bars are arranged overlapping each other.

[0004] In grates, the grate bars are arranged in several adjacent rows running in the direction of their longitudinal axis, so that the grate contains several grate bars arranged side by side transversely to their longitudinal axis. Gaps are provided between these transversely arranged grate bars to allow the passage of (combustion) air ("air gaps").

[0005] Such grates can be designed as sliding grates, with the overlapping grate bars forming a stepped upper surface of the grate.

[0006] To execute feed movements of the grate bars, the grate bars or individual grate bars are adjustable in the direction of their longitudinal extension. By moving the grate bars, and thus the grate bars coupled to them, back and forth, the material to be burned is conveyed along the sloping grate.

[0007] A problem with conventional grates is that the air gaps between the grate bars can become clogged, for example by combustion residues, and thus impede airflow to a greater or lesser degree. Obstructed airflow through the grate in the area of ​​the air gaps between adjacent grate bars impairs the efficiency of the combustion process.

[0008] DE 10 2008 056 468 B3 discloses a method for cleaning grates, comprising grate bars and grate rods arranged on the grate bars, between which air gaps are provided. The grate rods engage in receptacles in the grate bars. To clean the air gaps, the grate rods are moved relative to each other. The relative movements between the grate rods result from different clearances between the grate bars and the receptacles of the grate rods. DE 10 2008 056 468 B3 also describes a grate for carrying out this method. In the known grate, the clearance of the grate rods in the receptacles of adjacent grate bars is of different magnitudes, thus generating the relative movements. DE 10 2008 056 468 B3 also discloses how to effect vertical movements of grate rods perpendicular to the feed direction by providing wedge-shaped ramps on the grate bars.

[0009] Similar methods for cleaning the air gaps between grate bars and corresponding grates are known from DE 911 317 C and GB 2 503 319 A.

[0010] The invention is based on the objective of proposing an improved method for cleaning grates and a grate suitable for carrying out the method.

[0011] This problem is solved by a method that has the features of claim 1.

[0012] Insofar as the rust is concerned, the problem underlying the invention is solved with a rust which has the features of independent claim 4 directed to the rust.

[0013] The relative movements of adjacent grate bars occurring in the inventive method reliably and effectively clean air gaps located between the grate bars.

[0014] The invention also considers an embodiment of the method in which the grate bars are moved relative to each other both in the direction of their longitudinal extension and relative to each other by pivoting transversely to the direction of their longitudinal extension.

[0015] Relative movement between adjacent grate bars in the direction of their longitudinal extension can be achieved by engaging the grate bars in receptacles of adjacent grate bars arranged perpendicular to the direction of their longitudinal extension, with varying degrees of clearance. This embodiment has the effect that when the grate bars are moved back and forth, only those bars into which the grate bars engage with the receptacles with less clearance are moved, whereas the grate bars into which the grate bars engage with the receptacles with greater clearance are (initially) not moved, i.e., remain stationary, at least temporarily. Only when the grate bars contact the ends of the receptacles with greater clearance that are located at the front of the grate bars' movement, are these grate bars also moved, provided the magnitude of the grate bar's movement exceeds the clearance.

[0016] The difference in play between the grate bar receptacles and the grate bars themselves can be achieved either by making the receptacles larger and smaller, and / or by providing areas of different thickness on the grate bars.

[0017] The relative movement of adjacent grate bars transverse to the direction of their longitudinal extension can also be achieved by pivoting the grate bars about axes located in the area of ​​the receptacles into which the grate bars engage. According to the invention, the pivoting movement of the grate bars is selected such that the pivoting movements of adjacent grate bars are of different magnitudes and / or opposite to each other, resulting in the relative movements between adjacent grate bars according to the invention.

[0018] Further details and features of the invention will become apparent from the following description of preferred embodiments with reference to the partly schematic drawings. These show: Fig. 1 in side view of a feed grate, Fig. 2 in side view of a grate bar with a grate rod arranged in its receptacle with less play, Fig. 3 in side view of a grate bar with a grate rod arranged in its receptacle with greater play, Fig. 3 in top view of a part of the grate comprising four adjacent grate bars and their grate rod, Fig. 4 the position of the grate bars of the part of the grate of Fig. 3 After moving the grate bar, Fig. 5 a grate bar with areas of varying thickness, Fig. 6 in top view a part of a grate comprising three grate bars and with the grate bar with areas of varying thickness according to Fig. 5 , Fig. 7 the position of the grate bars of the part of the grate of Fig.6 After moving the grate bar, Fig. 8 shows a section of a wedge-shaped thickening grate bar, Fig. 9 shows a section of a wedge-shaped tapering grate bar, Fig. 10 shows overlapping wedge-shaped tapering and wedge-shaped thickening grate bars, Fig. 11 shows overlapping wedge-shaped thickening and wedge-shaped tapering grate bars, and Fig. 12 shows a top view of overlapping grate bars encompassing part of the grate. Fig. 10 und Fig. 11 .

[0019] A in Fig. 1 The grate 1 shown comprises several grate bars. The grate bars are arranged side by side transversely to their longitudinal direction, according to the desired width of the grate 1, with air gaps provided between adjacent grate bars. Fig. 1 shows that the grate bars in the grate 1 are arranged overlapping each other, resulting in a stepped top surface of the grate 1.

[0020] Each grate bar has a downwardly open receptacle 3 on its underside, in which a grate rod 4 is received. The grate bars can be moved back and forth along their longitudinal axis by moving the grate rods 4 in the receptacles 3 of the grate bars.

[0021] The end of each grate bar opposite the opening 3 rests on the adjacent grate bar in the longitudinal direction of the grate bars from above, for example approximately in the area of ​​its opening 3.

[0022] In the Fig. 1 In the illustrated embodiment, fixed grate bars 4 and adjustable grate bars 4 (movable back and forth) are provided in the direction of the longitudinal extent of the grate 1. In this embodiment of the grate 1, the movable grate bars 4 are mounted on a grate slide 2. The grate slide 2 is equipped with a drive (not shown) that allows the grate slide 2 to be moved back and forth. The grate slide 2 is moved in the direction of the Fig. 1 The double arrow 15, as indicated, moves back and forth – essentially horizontally. This back-and-forth movement of the grate bars 4 results in a movement of the grate 1 similar to a feed grate, so that the material to be fired is gradually conveyed downwards over the steps of the grate 1.

[0023] A preferred embodiment of the grate 1 is also considered in which all grate bars 4, and not just individual grate bars 4, are driven to move back and forth.

[0024] In one embodiment, it is provided that the clearance between grate bars 4 and receptacles 3 of the grate bars is of different sizes for grate bars arranged adjacent to one another.

[0025] The grate 1 comprises grate bars 5, in whose receptacles 3 grate bars 4 with smaller play ( Fig. 2a ) intervene, and grate bars 6, in whose receptacles 3 grate bars 4 with greater play ( Fig. 2b ) intervene. By providing grate bars 5 with receptacles 3 into which the grate bars 4 engage with less play ( Fig. 2a ) and grate bars 6 with receptacles 3 are provided, into which the grate bars 4 engage with greater clearance ( Fig. 2b ), it is achieved that when the grate bars 4 are moved back and forth between adjacent grate bars 5 and 6, a relative movement occurs in the direction of the longitudinal extent of the grate bars 5 and 6, as this Fig. 4 This is shown. The reason for this is that when the grate bars 4 are moved back and forth, grate bars 6 with receptacles 3 with a larger clearance between grate bar 4 and receptacle 3 are (initially) not moved, but only grate bars 5 with receptacles 3 with a smaller clearance between receptacle 3 and grate bar 4. Thus, grate bars 5 and 6 are moved by different distances in the direction of their longitudinal extension (horizontal or oblique to the horizontal), i.e., a movement of grate bars 5 and 6 relative to each other occurs.

[0026] An embodiment is also considered in which grate bars 7 have alternating areas of greater and lesser strength, in particular areas with a larger and areas with a smaller diameter ( Fig. 5 The grate bar 7, with thicker and thinner areas, engages, for example, in receptacles 3, which are dimensioned such that in areas of the grate bar 7 with a smaller diameter there is greater clearance between receptacle 3 and grate bar 7 than in areas of the grate bar 7 with a larger diameter ( Fig. 6 This allows uniform grate bars, for example grate bars 6 according to, to be used in grate 1. Fig. 2b to use. Thus, as in Fig. 7 indicated - when moving the grate bars 7 back and forth, the relative movement according to the invention between adjacent grate bars 6 is achieved.

[0027] The relative movement between adjacent grate bars 5 and 6 cleans the air gaps between adjacent grate bars 5 and 6 by removing combustion residues and / or unburned material from the (downward) air gaps.

[0028] Since the grate bars on the grate bars 4 are mounted by the engagement of the grate bars 4 in the receptacles 3 in such a way that the grate bars can be pivoted up and down around the axis of the grate bars 4, in addition to the relative movement between adjacent grate bars, a (horizontal) relative movement between adjacent grate bars in the direction of the longitudinal extent of the grate bars can be achieved by pivoting up and down.

[0029] In one embodiment, it is provided that, viewed longitudinally and transversely, grate bars 9 are alternately arranged ( Fig. 9 ) are provided, which taper, in particular wedge-shaped (-ΔH) and grate bars 8 ( Fig. 8 ), which thicken, particularly in a wedge shape (+ΔH). Therefore, the grate bars 8 and 9 have different heights at their ends furthest from their supports 3: -ΔH (grate bar 9) and +ΔH (grate bar 8), respectively. Fig. 10 und Fig. 11 Figure 1 shows how grate bars 8 and 9 are arranged alternately along their longitudinal axis such that a grate bar 8 always rests with its thinner (less tall) end on a thickening grate bar 9, and conversely, a grate bar 9 rests with its thicker (taller) end on a tapered grate bar 8. For example, the arrangement of grate bars 8 and 9 in grate 1 is such that in Fig. 10 shown series of alternating tapered grate bars 9 (-ΔH) and thickened grate bars 8 (+ΔH) and the in Fig. 11 The rows of alternating thickening grate bars 8(+ΔH) and tapered grate bars 9 (-ΔH) shown are arranged side by side as shown in Fig. 12 shown.

[0030] In this embodiment of the grate 1 according to the invention, the grate bars 4, which engage in the receptacles 3 of grate bars 8 and 9, which are arranged adjacent to each other in the direction of the longitudinal extension of the grate bars 8 and 9, are moved differently from one another. The different movement of the grate bars 4 can be achieved by - see Fig. 1 - only every second grate bar 4 is moved using the grate carriage 2. It is also considered to move adjacent grate bars 4 at different speeds, in different directions, and / or with different step sizes of the back-and-forth movement.

[0031] This ensures that, in the grate 1, when viewed in both directions (namely in the direction of the longitudinal extension of the grate bars 8 and 9 and transversely to the longitudinal extension of the grate bars 8 and 9), grate bars 8 (+ΔH) are always provided next to each other, which thicken away from the receptacle 3, and grate bars 9 (-ΔH) are provided, which thin away from the receptacle.

[0032] By moving the grate bars 8 and 9 with the aid of grate bars 4 engaging in their receptacles 3, the ends of the grate bars 8 and 9 furthest from the receptacles 3 slide on the upper side of grate bars 8 and 9 that are adjacent to each other in the direction of the longitudinal extent of the grate bars 8 and 9. When the ends of the grate bars 8 and 9 slide on a thickening grate bar 8 (+ΔH), they are pivoted upwards. When the ends of the grate bars 8 and 9 slide on a tapered grate bar 9 (-ΔH), they are pivoted downwards. Since grate bars 8, 9 with +ΔH and those with -ΔH are always arranged next to each other (see Figure 1), the following applies: Fig. 10 bis 12 ), due to the opposite pivot directions, the relative movements according to the invention between adjacent grate bars 8 and 9 result, transversely (vertically, namely up and down) to the longitudinal extent of the grate bars 8 and 9.

[0033] By moving the grate bars 8 and 9 back and forth using grate bars 4 engaging in their receptacles 3, the grate bars 8 and 9 move (pivot) up and down relative to each other in different directions (perpendicularly). This achieves the relative movements perpendicular to the longitudinal extent of the grate bars 8 and 9 that clean the air gaps between them.

[0034] Within the scope of the invention, it is also considered to move grate bars 5, 6, 8, 9 relative to each other not only transversely to the direction of their longitudinal extension, but also in the direction of their longitudinal extension. This can be achieved, for example, by positioning one of the grate bars 5 and 6 with +ΔH (similarly Fig. 8 ) and the other grate bar 5 or 6 with -ΔH (similar) Fig. 9 ) or one of the grate bars 8 and 9 with a receptacle 3 with a small clearance to the grate bar 4 (similar to Fig. 2a ) and the other grate bar 8 or 9 with a receptacle 3 with greater clearance to the grate bar 4 (similar to Fig. 2b ) is formed. Another way to move grate bars both in the direction of their longitudinal extension and transversely to it is to place a grate bar 7 on grate bars 8 and 9 according to Fig. 5 to use.

[0035] In summary, an embodiment of the invention can be described as follows: A grate 1 for furnaces comprises grate bars 5, 6, 8, 9 and grate rods 4, 7 engaging in receptacles 3 of grate bars 5, 6, 8, 9, with which grate bars 5, 6, 8, 9 can be moved back and forth in the direction of their longitudinal extent. Adjacent grate bars 5, 6, 8, 9 are moved relative to each other by pivoting movements during the back-and-forth movement in order to clean the air gaps between grate bars 5, 6, 8, 9. The direction of the relative movement between adjacent grate bars 5, 6, 8, 9 is essentially horizontal, parallel to the longitudinal extent of the grate bars 5, 6, and essentially perpendicular, by pivoting movements of the grate bars 8, 9 transverse to the longitudinal extent of the grate bars 8, 9.

Claims

1. A method for cleaning grates (1), comprising grate bars (4) and grate bars (5, 6, 8, 9) arranged on the grate bars (4), wherein grate bars (4) engage in receptacles (3) in grate bars (5, 6, 8, 9), and wherein air gaps are provided between grate bars (5, 6, 8, 9), wherein grate bars (5, 6, 8, 9) are moved relative to one another around an axis which lies in the region of the grate bar (4) which engages in its receptacle (3) in order to clean air gaps present between them, during their movements in the direction of their longitudinal extent, resting on adjoining grate bars (8, 9), characterized in that adjacent grate bars (8, 9) perform pivoting movements of different sizes and / or opposite to each other.

2. Method according to claim 1, characterized in that Grate bars (5, 6, 8, 9) are moved relative to each other by moving grate bars (4).

3. Method according to claim 1 or 2, characterized in thatGrate bars (5, 6, 8, 9) are moved relative to each other both in the direction of their longitudinal extension and transversely to the direction of their longitudinal extension.

4. Grate (1) for furnaces for carrying out the method according to one of claims 1 to 3, comprising a plurality of grate bars (8, 9) aligned parallel to one another and grate bars (4) aligned transversely to the grate bars (8, 9), wherein grate bars (4) engage in receptacles (3) in the grate bars (8, 9) and wherein the grate bars (8, 9) rest with their ends remote from the receptacles (3) on grate bars (8, 9) adjoining in the direction of their longitudinal extent, characterized in that adjacent grate bars (8, 9) are of different heights at their ends remote from the receptacles (3).

5. Grate according to claim 4, characterized in thatGrate bars (9) which taper towards their end remote from their holder (3) and grate bars (8) which thicken towards their end remote from the holder (3) are provided.

6. Grate according to claim 5, characterized in that in the grate (1), on the one hand, grate bars (8) which thicken and grate bars (9) which taper are provided next to one another, and on the other hand, in the direction of the longitudinal extension of grate bars (8, 9), grate bars (8) which thicken and grate bars (9) which taper are provided alternately one after the other.

7. Grate according to one of claims 4 to 6, characterized in that Grate bars (8, 9) are pivotably mounted on the grate bars (4) about axes located in the area of ​​their receptacles (3).