EP0165432B1 - Furnace, especially for the combustion of refuse, coal, wood and industrial waste - Google Patents

Abstract

1. Furnace with a sliding grate (7) consisting of grate rods (8) which forms a closure which forms a seal with the combustion chamber (1) on at least one side, which closure consists of a fixed sealing rail (5 or 5 and 6) and a sealing profile (13) which is attached to the sliding grate (7), parallel surfaces on the combustion chamber side and on the grate side defining a sealing gap (14), so that free lateral expansion and contraction of the sliding grate (7) due to the influence of temperature is possible, characterised in that the seeing profile (13) is connected directly to the sliding grate (7) by an anchoring rod (11).

Description

The present invention relates to a furnace with sliding grate consisting of grate bars, which forms at least on one side a sealing with the combustion chamber, which consists of a fixed sealing rail and a sealing profile attached to the sliding grate, parallel surfaces on the combustion chamber side and grate side defining a sealing gap, so that free lateral stretching and contraction of the sliding grate due to temperature influences is possible.

Various incineration grates are used in waste incineration plants. Larger systems in particular work with tensioned or pressed grates. This is easy to explain when you look at the combustion process. For grids that are not tensioned or not pressed, grate bars or grate blocks are usually used, which have an expansion play on the side. This expansion play is distributed across the entire grate width, sometimes unevenly. There is also an air gap on the sides of the combustion chamber walls as an expansion game. In these known grates, the pressure drop in the combustion air, given by the air gaps, is largely in the combustion material.

These gratings are not freely movable, but by means acting in the transverse direction, e.g. B. coil or leaf springs loaded.

When it comes to combustion, too, it can be observed that the combustion air always follows the path of least resistance. Is z. B. on a rust side of paper (high calorific value), this burns immediately. Vegetable waste on the other grate side (low calorific value) does not burn. The burnt paper creates a hole in the combustion material, through which the combustion air escapes uselessly without any significant resistance. The air necessary for the combustion of vegetable waste (low calorific value) escapes through the paper hole and is missing for the combustion of the components with low calorific value. This results in poor burnout.

In the case of tensioned or pressed grates, the pressure drop in the combustion air lies in the grate or grate covering and not in the combustion material. Air pressure builds up under the grate. The combustion air only flows into the medium to be burned through recesses, holes or slots in the grate. It is less important whether there is good or poorly flammable material on the grate.

Due to the higher resistance in the grate than in the material to be burned, the combustion air appears evenly on the material to be burned. The result is a good, even burnout of the combustion material. This result is achieved with more or less great effort and wear on parts.

In this sense, for example, a device for compensating dimensional changes in components caused by temperature fluctuations, in particular in the case of a grate or an input device for furnaces, has become known which has at least one displacement direction of a component which is movable in the direction of a compensation of the temperature fluctuations and must be compensated for and against this Component has a cheek that can be pressed by means of an adjusting device. The cheek is pivoted and supports are provided which can be moved in the direction of the displacement movement of the component or components to be compensated. (CH-PS-619 764.) However, this construction is quite expensive to implement and, with its moving parts, more prone to failure than if no such moving parts are provided.

Another construction discloses a feed grate for incinerators, in particular garbage incinerators, with rows of grate blocks which can be moved in the feed direction and run transversely to the grate. In this grate, each block transverse row is provided with a clamping device which engages one of the two outermost grate blocks of this transverse row and whose grate blocks are resiliently pressed against one another. (CH-PS-585 372.) This construction is also prone to failure and complicated because of the parts to be moved in rough operation at high temperatures

The present invention aims to provide a furnace which avoids temperature-compensating means as externally moved parts and is therefore more suitable in terms of operation and wear than the previously known designs.

Another object of the invention is to develop a combustion grate system which achieves a very high degree of efficiency with simple means, can be produced and operated inexpensively.

Correspondingly designed grate bars and built-in elements which spring-connect the grate bars serve for this purpose.

According to the invention, such a furnace is characterized in that the sealing profile is connected directly to the sliding grate by a tie rod.

Furthermore, the contents of the remaining claims are all essential to the invention.

The invention is subsequently explained, for example, using a drawing

• Fig. 1 einen Querschnitt durch den Feuerraum eines Ofens zur Verbrennung von Müll, Kohle, Holz und Industrieabfällen,
• Fig. 2 einen Ausschnitt aus Fig. 1 einer ähnlichen Rostanlage gemäss Fig 1,
• Fig. 3 eine Einzelheit aus einer Variante eines Feuerraumquerschnittes analog Fig. 1,
• Fig. 4 eine Variante analog Fig. 1 eines sehr breiten Feuerraumes,
• Fig. 5 eine Seitenansicht eines Wechselroststabes,
• Fig. 6 eine Aufsicht auf den Wechselroststab gemäss Fig. 5,
• Fig. 7 einen Schnitt durch den Wechselroststab gemäss Schnittlinie VII - VII der Fig. 5,
• Fig. 8 eine schematische Darstellung eines Ausschnittes aus einem Feuerraum eines Ofens zur Verbrennung von Müll, Kohle, Holz und Industrieabfällen, mit dem Rost in Seitenansicht.

Show it:

• 1 shows a cross section through the furnace of a furnace for the combustion of waste, coal, wood and industrial waste,
• 2 shows a detail from FIG. 1 of a similar grate system according to FIG. 1,
• 3 shows a detail from a variant of a combustion chamber cross section analogous to FIG. 1,
• 4 shows a variant analogous to FIG. 1 of a very wide combustion chamber,
• 5 is a side view of an interchangeable grate bar,
• 6 is a plan view of the removable grate bar according to FIG. 5,
• 7 shows a section through the exchangeable grate rod according to section line VII - VII of FIG. 5,
• Fig. 8 is a schematic representation of a section of a furnace of a furnace for burning garbage, coal, wood and industrial waste, with the grate in side view.

The side boundary of a furnace 1 of a furnace - it can also be a boiler - for the combustion of waste, coal, wood and industrial waste is indicated by two brick side walls 2 and 3. In the masonry of these side walls 2 and 3, a steel structure with two fixed sealing rails 5 and 5 and 6 can be seen. A sliding grate 7 is shown schematically. It is composed of grate bars 8, as shown in FIGS. 5 to 7. End profiles 10 can be seen on the side of the grate. A plurality of tie rods 11 distributed over the grate width each combine grate rod packs or blocks to connect them. On the sides of the grate 7, the sealing profiles 13 matching the rails 5 and 6 can be seen. With the respective upper end flanks of rails 5 and 6, you define column 14, which are selected so that the material to be burned cannot pass through to the side and the air passage remains regulated. On the other hand, this construction enables the grate 7 to be freely expanded and contracted to the side without the need for any clamping devices. This ensures that the grate works properly between the side walls 2 and 3, without any risk of jamming during the reciprocating movements of grate bars and without any additional mechanical actuation means.

It is possible to fasten the grate bars to blocks with one another with the calculated thermal expansion.

At the lateral ends of the grate surface formed in this way, left and right elements are attached to the sealing profiles 13 on the end grate bars of the fixed grate bar rows on the end grate bars of the fixed grate bar rows, which are usual with feed grates. These profiles 13 are connected to the fixed grate bars 8. If necessary, they can still be supported on the solid grating supports.

The grating that is held together in this way can expand and contract with the thermal expansion to the left and right without problems and without lateral pressure or tension.

The side rails 5 and 6 ensure expansion absorption and controlled air outlet.

In Fig. 1, in contrast to Fig. 2, a construction with side end of the grate 7 is shown, in which the sealing rails 5 and 6 are not attached directly to the brick side walls 2 and 3, but via brackets 20. This is also the Substructure for grate 7 with cross members 21 and 22 shown. In order to widen the grate 7, additional grate bars 24 arranged laterally at an angle are introduced, which are held on a holding rail 26 fastened to the steel structure with the aid of the support arms 27 and 28. These are also grate bars, as can be seen in detail in FIGS. 5 to 7. A support bracket 29 is arranged in the middle of the rod 24. The ash funnel 30 lies below the grate 7.

Fig. 3 shows a further, even better developed construction of the one side to a combustion chamber 1, in which construction above the inclined side grate bars 24 to produce a trough-like grate fixed inclined and side walls, fixed by the grate bars 24, and grate bars 32 are, the grate bar 32 in turn corresponds to a construction as shown in FIGS. 5 to 7 in detail. The side-by-side grate bars 32 are held by corresponding supports 33, since these bars 34 and 35, as explained later, are used with play.

Only one model of grate bars 8 is necessary for such grates. This type can be adjusted in width by removing it from the side, so that no fitting parts are required.

The constructions according to FIGS. 1 and 3 show how the grate can be enlarged laterally in a simple manner by obliquely arranged grate bars 24 and expanded like a trough by means of grate bars 32 additionally arranged above it, which contributes to a substantial increase in capacity of an existing oven. The grate bars 24 and 32, together with their end boundaries, define air outlet channels, as indicated by corresponding arrows.

This shows a simple way of broadening the grate in loose or bound and pressed grates by adding a grate bar, which is installed in position 0 to the desired slope or vertical. In the case of unpressed gratings, the installation can be fixed, also in the case of supported grates.

As with the pressed grate, a side end piece can be used. The grate surface is enlarged simply and inexpensively by this grate broadening and the dreaded edge fire is also eliminated. This is made possible by the in the Size of optional air outlet openings that keep the fire away from the side walls. The rising gases are mixed with secondary air and burned out. The air is blown back from the combustion chamber walls into the hot core zone by the air blown in in two directions. The radiant heat of the firebox is partially suppressed by the air curtain placed in front of the boiler pipes or the masonry. The heat of the ceramic walls or masonry, which is still absorbed by radiation, is reflected in the combustion chamber.

It is also possible to shake, shake or vibrate these so-called side grate elements. There are installation options for a wide variety of grate systems. As an extension and optimization of the aforementioned grate system or individually in existing plants and systems, one or more grate bars can be attached. The air volumes can be selected via column 14 to be determined.

4 shows a construction of a very wide combustion chamber with a wide grate 36 which is divided into two parts by means of a central web 37. This wide grate 36 is sealed in the middle with the aid of sealing rails 38 and sealing profiles 39 in the manner discussed, but allows the two grate parts to move freely to the side in the event of temperature fluctuations in the combustion chamber. As indicated, it is possible to install disc springs 40 between the individual grate bars in order to achieve a tie rod effect in this way, i. H. to ensure a corresponding elastic behavior of the grate in the transverse direction. Basically, the wide grate 36 has the same structure and can be supplemented as well as the grids shown in FIGS. 1 to 3.

5 to 7, a turning grate bar 8 can be seen, as this is preferably used for the grids described above. This rod 8 has a T-shaped cross section 41, as can be seen in the section plane VII - VII in FIG. 7. The support surfaces 42 of the individual grate bars 8, which are arranged laterally in a row, define the surface for the reception of the firing material in rows. It should be noted that in the case of the indicated feed grates, for example, the odd rows of grates are fixed and the even rows are arranged to be movable, as will be explained in FIG. 8 subsequently.

The grate bars 8, since they are so-called turning grate bars, are designed symmetrically with respect to the transverse central plane, which allows them to be turned by their polar axis (parallel to the cutting axis VII-VII in the central plane) by rotation through 180 °, e.g. B. if burning has occurred, the front part to rotate. In order to prevent jamming of the grate bars 8 on their axis-shaped holders, semicircular support shells 43 and 44 are formed, the diameter of which is larger in the horizontal direction than in the vertical, so that there is a longitudinal play of the grate bar 8 used with respect to the holding axis, a measure which prevents any jamming. Furthermore, a cleaning stroke will take place due to the forward and backward movement of the moving rods with the frictional resistances. Any foreign bodies that may have penetrated from the air gaps may fail due to the shifting of the grate bar. The storage takes place in the rear part of the grate bar 8, d. H. in the support shell 43 z. B.

Corresponding transverse walls 46 are provided in the area of the bearing shells 43 and 44 for reinforcement. Lateral oval passages 47, 48 and 49 allow the assembly of grate bars 8 lying next to one another in the form of groups, which in turn are combined to form the overall grate. On the inside of the grate bar 8, opposite the support surface 42 and on the side walls, there are, as shown in the figures, cooling pins 50, which significantly reduce the heat given off by the grate bars 8 to the cooling and combustion air and to the grate diarrhea funnel due to the massive increase in area improve. Between the transverse walls 46 on both sides of the center, the cooling pins 50 are additionally provided with conical lower parts 51 with a smaller diameter, shoulders at the transition point of the cooling pins 50 into the lower parts 51 serving to support duct sheet profiles 52 and 53, which profiles, as shown in FIG. 7 shows are attached laterally in the T-shaped main part. Not shown, but possible is the same arrangement for the front and back of the grate bar. The front and rear end wall of each grate bar 8 are each provided with an air nozzle 54 and 55, which is inclined upwards, i. H. directed at an angle to the support surface 42, direct an air jet which does not aim at the support surface 42 of the grate bar 8 in front of it and thus protects it from excessive surface temperatures as a result of fanned combustion. It is worth noting the targeted air outlet of the side wall nozzles on the turning grate bars, which aim into the combustion bed and do not flow against the grate bars. This avoids excessive heating of the grate bars. There are no metal melts caused by local overheating, which disrupt operational safety and reduce the service life of the grate bars due to excessive wear. The air nozzles 54 and 55, as can be seen, converge towards the nozzle mouth, whereby an accelerated air flow is generated in the nozzle. The turbulence of this air jet is improved in that the nozzle guide walls are designed like a cone and not parallel walls.

The cooling air passes through the rear air nozzle 54 into the space 58 in the area of the upper pins 50, which, as shown, is preferably closed by means of the duct sheet profiles 52 and 53, in such a way that the air flow brings optimal heat transfers to the cooling pins arranged in staggered rows. The lower parts 51 of the cooling pins 50 also allow the heat-emitting surfaces to be enlarged. Through holes 56 and 57 in the transverse walls 46 result in the continuous air duct informing the space 58 from the air nozzle 54 to the air nozzle 55.

8 shows a combustion chamber 60 in longitudinal section with respect to the grate, with a feed plunger 61 and an inclined grate 62 assembled from fixed grate bars 8 and a subsequent combustion grate 63. The firing material, coming from the feed plunger 61, arrives, as shown by reference number 65. onto the sloping grate 62 and slips on the incineration grate 63 in order to then fall into the slag shaft 67 completely burned out as slag material. With the help of an inclined grate 62, this construction allows the combustion of the fired material to be significantly improved and prevents the not yet completely burned-out material from falling early into the slag shaft 67 via so-called rust falls.

So-called rust falls are installed in incineration plants and especially in waste incineration plants. These have the task of loosening and rearranging the combustion material as it falls.

As mentioned, the intention here is to replace these lintels with the slanted gratings 62. This helps to avoid deflagrations and fluctuations in operation during the dropping process. The grate area is enlarged and the burnout section is extended. These inclined gratings 62 can be designed to be stationary or movable. Problems of rust falls with the slag caking, high wear and tear and training with cooling plates and their air requirement are thus eliminated. A built-in sloping grate 62 in a waste incineration plant increases the active grate area significantly and produces very good results through increased performance and good burn-out. The position of the grate bars results in a loosening of the waste in this case with a targeted air entry into the combustion material.

The illustration according to FIG. 8 also shows how the grate bars 8 are arranged on the supports of the substructure of the grates on corresponding supports or axles and each rest on the upstream rows of grate bars with the front part. In this case, in this example of the combustion grate 63, the odd grate bar rows are fixed components of the grate in the feed grate, as is indicated by double arrows, while the straight grate bar rows in a known manner by pushing the support profiles with their front parts back and forth on the following push off the fixed grate bar row of accumulated material 65, in which way the material 65 is known to be moved forward in the direction of the slag shaft 67.

As shown in FIG. 8, the grate frame can lie horizontally or can be arranged sloping towards the slag shaft 67.

These constructions are suitable as a whole or in individual system parts, for new as well as for "existing" combustion grate systems.

• 1. Verwendung von Roststäben besonderer Konstruktion, insbesondere Wenderoststäben
• 2. Rostzusammenbau mit Dehnungs-DichtungsElementen
• 3. Rostverbreiterung
• 4. Verbrennung der flüchtigen Bestandteile mit gleichzeitiger Kühlung der Feuerraumwände
• 5. Roststäbe für Sekundärlufteindüsungen 70, Brennkammerumlenkungen 71 und Brennräume 60
• 6. Ersetzen der Roststufen bzw. Stürze durch feststehende oder bewegliche Schrägroste.

The Zeil is essentially achieved by:

• 1. Use of special construction grate bars, especially turning grate bars
• 2. Grate assembly with expansion sealing elements
• 3. Rust broadening
• 4. Combustion of the volatile components with simultaneous cooling of the combustion chamber walls
• 5. Grate bars for secondary air injection 70, combustion chamber deflections 71 and combustion chambers 60
• 6. Replace the grate steps or lintels with fixed or movable inclined grates.

Claims (5)

1. Furnace with a sliding grate (7) consisting of grate rods (8) which forms a closure which forms a seal with the combustion chamber (1) on at least one side, which closure consists of a fixed sealing rail (5 or 5 and 6) and a sealing profile (13) which is attached to the sliding grate (7), parallel surfaces on the combustion chamber side and on the grate side defining a sealing gap (14), so that free lateral expansion and contraction of the sliding grate (7) due to the influence of temperature is possible, characterised in that the seeing profile (13) is connected directly to the sliding grate (7) by an anchoring rod (11).

2. Furnace according to Claim 1, characterised in that the grate rods, forming a whole, are held together in groups, expansion elements (40) being provided between groups, which elements operatively connect adjacent grate rods (8) resiliently.

3. Furnace according to Claim 2, characterised in that disc spring-like elements (40) are provided as expansion elements. (Fig. 4).

4. Furnace according to Claim 1, characterised in that a sloping grate (62) consisting of grate rods, especially reversing grate rods (8), is inserted before the combustion grate (63).

5. Furnace according to at least one of Claims 1 to 4, characterised in that the grate rods (8) have air nozzles (54, 55) which are directed forwards, preferably upwards, and an air duct (58) leading along the grate rod (8) to the front air nozzle (55) is provided to guide the air around the parts of heat-emitting elements (50), e.g, studs or ribs, which are close to the wall, characterized in that parts (51) of said elements, lying outside the air duct (58), protrude into an air-cooling area in order to ensure cooling of the grate rod (8) even if the air duct (58) is blocked. (Fig. 5).

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