EP0757206B1 - Grate for a furnace - Google Patents

Abstract

The grid plates (3,4) have openings or slots (8) for feeding in primary air. The back ends of the plates are connected to a fixed or movable support (6). The front ends of the plates rest on the adjacent grid plate. The grid plates in one row are joined by connections so that adjacent plates can move to a limited extent in a longitudinal direction, and can swivel in relation to their support. The undersides of the grid plates have cooling ducts (9) between the openings or slots and formed by the grid plates themselves and by the hollow profiles (10) on the grid plates. The cooling ducts run parallel with the grid longitudinal direction and are in series or sinusoidal.

Description

TECHNICAL AREA

The invention relates to a grate for a furnace with at least one grate track with several in the longitudinal direction alternating, delimited on both sides by side walls Fixed bar rows and moving bar rows from liquid-cooled Rust plates, which rust plates with a variety of in Groups of openings or slots arranged for primary air supply are provided and in the area of their rear end swiveling with a fixed or movable grate plate support are connected and with their front end on the adjacent one Rest the grate plate, the grate plates one Row of grate plates each arranged below them Connection means are connected such that neighboring Grate plates can be moved against each other to a limited extent in the longitudinal direction of the grate and with regard to the grate plate carrier assigned to them are pivotable to a limited extent.

The invention relates to a prior art, as it results for example from CH-PS 684 118.

TECHNOLOGICAL BACKGROUND AND PRIOR ART

Grates of the type mentioned are used for burning and at the same time transport of fired goods and above all used in waste incineration plants.

In addition to air-cooled grate plates - this is where the serves Slots in the grate plates from primary air supplied from below at the same time as a coolant - have been water-cooled for many years Grate plates used to the service life of the grate plates to increase.

So in the German patent application St 942 V / 24f from 10.9.19953 a poker grate with alternating fixed and movable Grate bar rows proposed, in which the fixed Grate bar rows from transverse to the grate direction, in there are cooling pipes switched on in the boiler water circuit, to which the pipes, some of which have extensive grids, fit snugly are attached.

The thrust combustion grate known from CH-PS 684 118 has a grate plate, which consists of a substantially rectangular Hollow body made of sheet metal, which hollow body on the a connector on one side of its underside and on the other side of its underside a discharge pipe for the supply and discharge of a cooling fluid flowing through the hollow body having. The primary air is supplied by a variety of tubes with round, elliptical or slit-shaped cross-section, which pipes the hollow body push through.

While with the grate after the German patent application only has a comparatively modest cooling effect, is the rust according to CH-PS 684 118, due to the large number of tightly welded thin tubes for primary air flow, comparatively complex to manufacture.

SUMMARY OF THE INVENTION

The object of the invention is based on the prior art based on creating a grate that is easy to manufacture is optimally cooled.

According to the invention, this object is achieved in that cooling channels are provided on the underside of the grate plate between the openings or slots, these Cooling channels on the one hand through the grate plate itself and on the other formed by hollow profiles attached to the grate plate are.

The advantage of the invention can be seen in particular in that cooling function and primary air supply are independent of each other are. This means that e.g. in contrast to the execution According to CH-PS 684 118, the primary air is not through the liquid flow Hollow body must be directed, but only through the openings or slots in the grate plate, see above that the heat exchange between the two media is only on the the smallest possible distance, namely the thickness of the (massive) Rust plate, done. However, the cooling effect is sufficient because only comparatively narrow areas of the grate plate not in direct contact with the coolant. There however, cooling takes place by heat conduction. The production the grate plate including cooling channels is economically simple because only comparatively simple connections preferably welded connections, which are also easy to check and, if necessary, touch up are.

Especially viewed as currently particularly advantageous Embodiment of the invention with in the longitudinal direction of the grate flow through cooling channels can be the distribution of the openings or slots for the primary air supply practically unchanged to be kept. Among other things, this means that existing grate plates can be retrofitted with such cooling channels or in the case of replacement procurement of the design and manufacturing technology Effort is minimal and no adjustment in the control / regulation the primary air supply is necessary.

Another significant advantage of the invention is that that it is possible to arrange the To meet cooling channels so that fresh cooling water initially due to the thermally most stressed front end of the grate plate flows. Also with regard to the location of the inlet and outlet connections there is the greatest possible freedom for the coolant, so that it is usually possible in the area of the grate plate end to arrange.

Embodiments of the invention and the achievable therewith Advantages are explained below with reference to the drawing.

BRIEF DESCRIPTION OF THE DRAWING

Fig.1

eine perspektivische Darstellung eines herkömmlichen aus Bewegtstabreihen und Feststabreihen aus Rostplatten bestehenden Vorschubrostes;

Fig.2

einen vereinfachten Querschnitt durch eine Rostplatte;

Fig.3

ein erstes Ausführungsbeispiel einer Rostplatte mit quer zur Rostlängsrichtung verlaufenden, mäanderförmigen seriell durchströmten Kühlkanälen;

Fig.4

einen Querschnitt durch die Rostplatte gemäss Fig.3 längs deren Linie AA mit Kühlkanälen mit Halbkreisquerschnitt;

Fig.5

eine Abwandlung von Fig.4 mit Kühlkanälen mit dreicksförmigem Querschnitt;

Fig.6

eine Abwandlung von Fig.4 mit Kühlkanälen mit trapezförmigem Querschnitt;

Fig.7

eine Abwandlung von Fig.4 mit Kühlkanälen mit rechteckigem Querschnitt;

Fig.8

ein zweites Ausführungsbeispiel einer flüssigkeitsgekühlten Rostplatte mit quer zur Rostlängsrichtung verlaufenden parallel durchströmten Kühlkanälen;

Fig.9

einen Querschnitt durch die Rostplatte gemäss Fig.8 längs deren Linie BB mit Kühlkanälen mit Halbkreisquerschnitt;

Fig.10

ein drittes Ausführungsbeispiel einer flüssigkeitsgekühlten Rostplatte mit in Rostlängsrichtung verlaufenden seriell bzw. mäanderförmig durchströmten Kühlkanälen;

Fig.11

einen Querschnitt durch die Rostplatte gemäss Fig.10 längs deren Linie CC mit Kühlkanälen mit Halbkreisquerschnitt;

Fig.12

einen Längsschnitt durch die Rostplatte gemäss Fig.10 längs deren Linie DD in vergössertem Massstab;

Fig.13

ein viertes Ausführungsbeispiel einer flüssigkeitsgekühlten Rostplatte mit in Rostlängsrichtung verlaufenden parallel durchströmten Kühlkanälen;

Fig.14

einen Querschnitt durch die Rostplatte gemäss Fig.13 längs deren Linie EE mit Kühlkanälen mit Halbkreisquerschnitt;

Fig.15

eine der Ausführungsform nach Fig.3 entsprechende mehr ins Detail gehende Draufsicht auf die Oberseite einer Rostplatte mit seriell durchströmten Kühlkanälen;

Fig.16

einen Querschnitt durch die Rostplatte gemäss Fig.15 längs deren Linie GG;

Fig.17

eine der Ausführungsform nach Fig.8 entsprechende mehr ins Detail gehenden Längsschnitt durch eine Rostplatte mit quer zur Rostlängsrichtung verlaufenden seriell durchströmten Kühlkanälen längs der Linie HH in Fig.18;

Fig.18

einen Querschnitt durch die Rostplatte gemäss Fig.17;

Fig.19

einen Querschnitt durch die Rostplatte gemäss Fig.17 längs deren Linie II.

Exemplary embodiments of the invention are shown schematically in the drawing. The same or equivalent parts are provided with the same reference numerals in all figures. It shows:

Fig. 1

a perspective view of a conventional moving rod rows and fixed bar rows of grate plates existing feed grate;

Fig. 2

a simplified cross section through a grate plate;

Fig. 3

a first embodiment of a grate plate with meandering cooling channels running serially through the grate longitudinal direction;

Fig. 4

a cross section through the grate plate according to Figure 3 along the line AA with cooling channels with a semicircular cross section;

Fig. 5

a modification of Figure 4 with cooling channels with a triangular cross-section;

Fig. 6

a modification of Figure 4 with cooling channels with a trapezoidal cross-section;

Fig. 7

a modification of Figure 4 with cooling channels with a rectangular cross-section;

Fig. 8

a second embodiment of a liquid-cooled grate plate with parallel through-flow cooling channels running transversely to the grate longitudinal direction;

Fig. 9

a cross section through the grate plate according to Figure 8 along the line BB with cooling channels with a semicircular cross section;

Fig. 10

a third embodiment of a liquid-cooled grate plate with cooling channels running in series or meandering fashion in the longitudinal direction of the grate;

Fig. 11

a cross section through the grate plate according to Figure 10 along the line CC with cooling channels with a semicircular cross section;

Fig. 12

a longitudinal section through the grate plate according to Figure 10 along the line DD on an enlarged scale;

Fig. 13

a fourth embodiment of a liquid-cooled grate plate with cooling channels running in parallel in the longitudinal direction of the grate;

Fig. 14

a cross-section through the grate plate according to Figure 13 along the line EE with cooling channels with a semicircular cross-section;

Fig. 15

a more detailed plan view corresponding to the embodiment of Figure 3 on the top of a grate plate with cooling channels flowed through in series;

Fig. 16

a cross section through the grate plate according to Figure 15 along the line GG;

Fig. 17

a more detailed longitudinal section corresponding to the embodiment according to FIG. 8 through a grate plate with cooling channels running through in series and transverse to the grate longitudinal direction along the line HH in FIG. 18;

Fig. 18

a cross section through the grate plate according to Fig.17;

Fig. 19

a cross section through the grate plate according to Fig.17 along the line II.

WAYS OF CARRYING OUT THE INVENTION

The grate according to Figure 1 has a grate track 1 on both sides is limited by side walls 2. It can also have two or more grating tracks arranged side by side, separated by central beams show. The grate track 1 consists of in the grate longitudinal direction alternating rows of fixed bars 3 and 4 rows of moving bars Grate plates. At the rear end of the grate plate is a half-open one Pipe piece 5 attached, with which the grate plate on a grate plate support, which here as a rod 6 with a circular cross section trained, rests (see Fig. 2). The rows of fixed bars assigned grate plate supports are fixed to the side walls 2 connected, which are assigned to the moving rod rows Grate plate supports are interconnected and in the longitudinal direction of the grate slidably arranged and can by both sides arranged double-acting hydraulic or pneumatic cylinders relative to the fixed grate plate supports and be moved around.

The grate plate itself consists of a largely flat Plate that is bent down at the front end and there into a slide piece 7 running approximately parallel to the plate ends. There the grate plate lies on the in the direction of movement next to the grate plate. In the level section the red plate is three rows narrower in the example Slots 8 or openings are provided that face down extend in both the longitudinal and transverse directions and run parallel to the grate longitudinal direction. Through these slots 8, the primary air is supplied from the underside of the grate.

Insofar such grids are known and for example in EP 0 650 017 A1 described and illustrated in more detail. Of the For the sake of good order, it should be noted that this is known Rust each row of grate bars from a variety of narrower ones There are grate bars, with the primary air passing through the gap between two neighboring grate bars is guided.

As already mentioned at the beginning, the grate bars (grate covering) exposed to considerable thermal stress. Because cooling with the one flowing from below through the grate Primary air alone is not sufficient to have a rust coating To achieve a long service life, the invention provides that cooling channels 9 are provided on the underside of the grate plate are between the openings or slots 8 3.4 these cooling channels on the one hand through the grate plate itself and on the other hand through hollow profiles attached to the grate plate 10 are formed, as shown in simplified form in FIGS. 3 and 4 is. Through these cooling channels, a cooling liquid, preferably water. The hollow profiles 10 are for example half-tubes 10a with a semicircular or oval Cross section on the underside of the grate plate 3 (4) outside the slots 8 are welded. In addition to hollow profiles in the form of half tubes 10a (Fig.4) come with hollow profiles Triangular cross section 10b (Fig.5), hollow profiles with trapezoidal Cross section 10c (Fig.6) or hollow profiles with rectangular Cross section 10d (Fig.7) for use. Of course other cross-sectional shapes are possible, e.g. Hollow profiles with oval cross section.

In the case of the arrangement according to Fig. 3 or 4, the flow takes place transverse to the grate longitudinal direction and serial or meandering from the supply nozzle 11 on one narrow side of the grate plate to the discharge nozzle 12 on the opposite narrow side the grate plate 3 (4).

In the variant of a shown in Figures 8 and 9 Grate plate with three grids running transversely to the longitudinal direction of the grate Cooling channels 9 is carried out in parallel by flow, the the narrow sides of the grate plate 3 (4) directly adjacent cooling duct sections act as cooling water distribution chambers.

FIGS. 10 to 12 show an embodiment of the invention, in which the cooling channels run in the red longitudinal direction and are serially flowed through in a meandering manner, with each on The beginning and end of the grate plate are deflected.

Based on the variant according to FIG. 8, it can also be used in the red longitudinal direction running cooling channels a parallel flow can be realized, as is shown in FIGS. 13 and 14 is illustrated. Here they form almost over the whole Grate plate width extending cooling duct sections on A kind of cooling water distribution chamber at the front and rear end of the grate plate 3 (4). The feed is preferably carried out particularly thermally highly stressed front end.

Figures 15 and 16 and Figures 17 to 19 include opposite the previously presented embodiment variants of the invention more detailed representations of rust plates, whereby the embodiment shown in Figures 15, 16 in principle the embodiment according to FIG. 4, which is shown in FIGS. 18 corresponds in principle to the embodiment according to FIG. 10.

The grate plate 3 (4) is through the grate in the longitudinal direction Webs or frames 13 stiffened; the webs on the narrow sides of the slab are designated 13L and 13R, respectively. Analogous to Fig. 4 are liquid-tight on the underside of the grate plate 3 (4) half pipes 10a attached, preferably welded. This run across the grate longitudinal direction between the three Slot groups. As can be seen from the cross section according to Fig. 16, the slots 8 extend so far to the half-tubes 10a that there is enough space for the attachment of weld seams S remains. The supply and discharge of the cooling water takes place at the rear end of the grate plate 3 (4) by means of a feed connector 11 or discharge nozzle 12 in the middle section of the grate plate 3 (4). A first cooling duct 9a leads from the nozzle 11 to the narrow side of the grate plate 3 (4), then emerges from the plate level down and then runs at the free end of the web 13L to the front end of grate plate 3 (4) and then opens in the cooling channel 9f. This is through a quarter pipe 10a downward end 3 '(4') of the grate plate 3 (4) and that Slider 7 limited. The cooling channel 9f extends over the entire width of the grate plate 3 (4). After redirection at the other plate narrow side, it flows through the cooling channel 9e in the rounding of the grate plate (Fig. 16) is in turn at the end of the plate deflected, then flows through the cooling channels 9d, 9c, 9b and 9a 'and leaves the grate plate through the discharge nozzle 12th

With the described arrangement of the flow through the series Cooling channels 9a, ... is achieved that the thermally most stressed front end of the grate plate of fresh cooling water is applied, while the rear end is rather less intense is cooled, which is portable. Through the stoking movements (Relative movements between movable 4 and fixed Grate plates 3 is the rear section of the grate plate 3 (4) in the Medium less exposed to the combustion material on the grate than their front end. Could be considered disadvantageous at best be that the length of the slots 8 is not freely selectable, because there is space for attachment between adjacent slot groups the cooling channels 9a, ... must remain. It may therefore be necessary be the number of slots 8 per slot group increase.

A particularly preferred embodiment of the invention is shown in FIGS. 17 to 19. It corresponds in principle to the embodiment shown in FIG. 10, that is to say has cooling ducts 9 _i (i = 1,..., 16) with a triangular cross section that run in the longitudinal direction of the grate. These are made of sheet steel with an apex angle of approximately 60 degrees and run between the slots 8 and parallel to them. The cooling water is supplied in the middle section of the grate plate 3 (4). From there, a first transverse channel 14 leads to the narrow side of the grate plate. This continues in a lateral cooling channel 9L on the left edge of the plate and is formed by a plate 15 bent at right angles (FIG. 19). At the front edge of the plate, the cooling water is deflected by 180 degrees and flows through the first triangular channel 9 ₁ to the rear end of the grate plate. So that the entire front part 3 '(4') of the grate plate 3 (4) is covered by the cooling water, a deflection plate 16 is provided in the extension of the slots 8, which forces the flow downwards. The renewed deflection at the rear grate plate end takes place through a dividing wall 17 which runs transversely to the grate longitudinal direction and at the same time delimits the transverse channel 14. Then the cooling water flows through the next cooling channel 9 ₂ , is again deflected at the front end of the grate plate. A dividing wall 18 running in the longitudinal direction of the grate separates the cooling channels 9 ₁ and 9 ₂ . On the other narrow side of the grate plate, the cooling water is guided to the rear end of the grate plate through a second lateral cooling channel 9R, flows through a second transverse channel 14 ′ and leaves the grate plate through the discharge nozzle 12.

As can be seen from a view of FIG. 17, this preferred embodiment of the invention offers the advantage over the embodiment according to FIGS. 14 and 15 with comparatively little additional effort that practically the entire surface of the grate plate is in direct contact with the cooling water. Only the narrow strips between adjacent cooling channels 9 _i (i = 1, ... 16), where the slots 8 are, are not directly cooled. For this there is enough space (in the longitudinal direction of the grate) to accommodate the slots 8 required for the primary air supply. The thermally highly stressed front of the grate plate is also optimally cooled because there are practically no dead water zones and the deflection by the deflection plates 16 in connection with the 180 degree deflection taking place there results in favor of heat exchange.

Based on that in CH-PS 684 118, the invention offers also the possibility of cooling the coolant to control the temperature To use grate or individual grate sections by each one or more adjacent ones as required by the furnace Grate plates are charged with "preheated" coolant, to the required grate plate temperature to be able to adjust.

LIST OF DESIGNATIONS

1

Rostbahn

2nd

Side wall

3rd

fixed grate plates

3rd

downward bent front end of 3

4th

movable grate plates

4 '

downward bent front end of 4

5

half-open pipe section

6

Rod (grate plate support)

7

Slider

8th

Slots in 3 and 4

9 ...

Cooling channels

10th

Hollow profiles

10a

Half pipes

10a '

Quarter pipe

10b

Triangular cross-section tubes

10c

Trapezoidal tubes

10d

Rectangular cross-section tubes

11

Liquid supply nozzle

12th

Liquid discharge nozzle

13

Stiffening bars

13L, 13R

Stiffening webs on the narrow sides of the grate plate

14

first cross channel

14 '

second cross channel

15

bent sheet

16

Baffles

17.18

Partitions

S

Welds

Claims (9)

1. Grate for a firing system, with at least one grate conveyor having a plurality of fixed bar rows and moving bar rows alternating in the longitudinal direction, which are limited on both sides by side walls (2) and which are composed of liquid-cooled grate plates (3; 4), said grate plates being provided with a multiplicity of orifices or slits (8), arranged in groups, for the supply of primary air and each being pivotably connected respectively to a fixed and a movable grate plate carrier (6) in the region of their rear end and resting with their front end on the adjacent grate plate, the grate plates of a grate plate row being connected in each case by connection means arranged underneath these, in such a way that adjacent grate plates are displaceable relative to one another to a limited extent in the grate longitudinal direction and are pivotable to a limited extent with respect to the grate plate carrier assigned to them, characterized in that there are provided, on the underside of the grate plate, cooling ducts (9) which are located between the orifices or slits (8), these cooling ducts being formed, on the one hand, by the grate plate itself and, on the other hand, by hollow profiles (10) attached to the grate plate.
2. Grate according to Claim 1, characterized in that the cooling ducts (9) extend essentially parallel to the grate longitudinal direction.
3. Grate according to Claim 2, characterized in that the cooling water can flow through the cooling ducts (9) serially, or in a meander-shaped manner, or in parallel.
4. Grate according to Claim 1, characterized in that the cooling ducts (9) extend essentially transversely to the grate longitudinal direction.
5. Grate according to Claim 4, characterized in that the cooling water can flow through the cooling ducts (9) serially, or in a meander-shaped manner, or in parallel.
6. Grate according to Claim 2 or 3, characterized in that the cooling ducts each extend between two adjacent slit groups (8) in each case.
7. Grate according to Claim 4 or 5, characterized in that the cooling ducts (9) each extend between two adjacent slit groups in each case.
8. Grate according to one of Claims 2 to 7, characterized in that, in the case of a parallel throughflow, cooling water distribution and cooling water collecting chambers are provided.
9. Grate according to one of Claims 1 to 8, characterized in that the arrangement of the cooling ducts is made such that cooling water flows in a controlled manner first through the front end of the grate plate.

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