EP1996863A1

EP1996863A1 - Liquid-cooled grill comprising wear plates

Info

Publication number: EP1996863A1
Application number: EP07710802A
Authority: EP
Inventors: Martin Stiefel; Thomas Stiefel
Original assignee: Doikos Investments Ltd
Current assignee: Doikos Investments Ltd
Priority date: 2006-03-17
Filing date: 2007-03-16
Publication date: 2008-12-03
Also published as: WO2007107024A1; CN101405542A; CA2645442C; HK1131204A1; US8256361B2; CN101405542B; CA2645442A1; US20090101320A1; JP2009530578A; JP5113829B2

Abstract

The invention relates to a grill consisting of liquid-cooled grill plates and liquid-cooled lateral panels, the surfaces of which are provided with wear plates (1) connected to the liquid-cooled grill plates (2) and lateral planks in a heat-conducting manner. Said wear plates (1) consist of a wear-resistant material which must however by cooled. Advantageously, a layer of a heat-conducting material in the form of a highly heat-conducting soft silicon film (3) is clamped between the liquid-cooled grill plates (2) and lateral panels and the wear plates (1), said layer providing a good heat transfer between the wear plates (1) and the permeable grill plates (2) and central panels. It is thus ensured that, during operation, the wear plates (1) always remain in a non-critical temperature range as they are cooled by the underlying grill plates (2) and lateral panels which are cooled to ca. 50°C g.

Description

Liquid-cooled grate with wear plates

So far, built for a liquid-cooled grate for waste incineration water-cooled grate plates as they emerge, for example, from EP 0 621 449, which are arranged in a staircase overlapping arranged to form a grate. Each grate step is in the running direction of the entire grate forward and backward displaced to produce a stoking and transport movement for the lying on the grate kiln.

These liquid-cooled grate plates are made of steel, which is about 10-12mm thick, is folded and then welded together in two half-shells, creating a cavity through which the coolant, such as cooling water, a suitable oil or a specific Components offset coolant can flow. For example, Hardox is used for the surface, because it is much harder, ie ordinary steel and therefore more resistant to wear. On the other hand, Hardox is temperature sensitive and softens above about 280 °. These steel grate plates are relatively expensive to manufacture and the welding together of the two half-shells is delicate. Welding is done in a water bath to avoid heat hardness of the Hardox, to continuously heat from remove the weld, because the temperature of Hardox must remain below about 28O ⁰ C, because only up to this temperature up Hardox remains hard. After welding, the grate plate must be straightened because it is inevitably distorted by welding, as welding produces high temperatures in very local areas and large temperature gradients in the plate.

From DE 196 13 507 C1 it is known, at those points of the grate plate tops, where the cascaded superimposed grate plates touch and by the feed motion wear occurs, provide separate wear plates. These can be replaced if necessary, so that the main body of the grate plate can continue to be used. The wear plates are DE 196 13 507 C1 placed directly on the body and welded with them.

The US 6,266,883 also shows a solution in which the grate plate includes a relatively thin support plate as a wear plate, which is preferably fixed to the grate plate along the edges fixed with welds and then forms a highly wear-resistant surface. As a material for these wear plates rolled steel is given a special wear-resistant alloy, wherein it is cured by a temperature or is provided with a specially hard surface layer. Such steel was allegedly commercially available, but so far been used for special machinery, but not in connection with grate plates.

In these solutions mentioned here, the wear plates are placed directly on the cooled grate plates. Although these wear plates macroscopically rest on the cooled grate plates, it turns out that the heat transfer from the wear plate to the cooled grate plate is very limited. Accordingly, the liquid cooling of the underlying cooled grate plate is less effective. Because the bottom of the wear plates on the one hand, as well as the tops of the On the other hand microscopically, the plates are microscopically only pointwise or at small elevations on each other and touch only there full, so that only in these places an effective heat transfer takes place, while everywhere else Air gaps have an insulating effect. , ,

The object of the present invention is therefore to provide a liquid-cooled grate of grate plates and planks, which are made of non-temperature-sensitive, cheap iron or steel, which, but still bring the required wear resistance by equipped with replaceable wear plates is, and at which at the same time a much improved heat transfer from the Verschleissplatte is achieved on the liquid-cooled grate plate or the plank, so that the cooling effect is hardly limited despite the attached wear plate.

This object is achieved by a liquid-cooled grate, consisting of several permeable by a liquid grate plates and side planks whose surface are each equipped with one or more Verschleissplatten which are thermally conductively connected to the liquid-cooled grate plate or the side plank, said this Characterized in that in order to achieve the heat transfer from the Verschleissplatten to the liquid-cooled grate plates and side planks between the Verschleissplatten and the liquid-cooled grate plates and side planks ever a highly heat-conducting film is clamped and the Verschleissplatten are releasably connected to the liquid-cooled grate - and side planks.

Reference to the drawings, the invention will be further described and its function will be explained;

It shows: Figure 1: A single grate plate of the grate with a wear plate and a heat-conducting intermediate layer in a perspective view, wherein the three parts are shown separated from each other;

Figure 2: A single grate plate of the grate with two adjacent wear plates and a heat-conducting; Intermediate layer in a perspective view; ,

Figure 3: A single grate plate with Verschleissplatte in a schematic cross section; ,

Figure 4: A sectional view across a liquid-cooled grate with two grate webs;

FIG. 5: The central plank between two grate webs enlarged in a cross section;

FIG. 6: A lateral guide rail of the grate track enlarged in a cross section.

This liquid-cooled grate plate with separate Verschleissplatte to build such a liquid-cooled grate is built in principle exactly the same as a conventional, only that is not necessarily used as a building material tempered steel, but about iron, structural steel, cast or a combination thereof. This liquid-cooled grate plate as shown in Figure 1 thus forms a stream of ble ble body 2 by zürn example is designed as a hollow body, with a supply and discharge pipe for the cooling liquid. This coolant is. usually water, but oils or an oil or water mixed with specific components can also be used as the cooling liquid. The plate is made by, for example, welding two half shells together, including a cavity become. However, such welding does not need to be carried out in a water bath because the steels used readily withstand higher temperatures. Warping is much less to be feared because of the material-specific properties of such steels. The flow-through body 2 may also consist of a solid material plate, which is interspersed by suitable holes or cavities.

To give such a plate the required wear resistance, the surface must, however, be much harder than an ordinary structural steel. The solution consists in the fact that the top of the grate plate, where it comes into contact with the kiln, is equipped with at least one separate wear plate 1. As material for such a closure plate 1 comes ^' any material in question, which is sufficiently hard and mechanically resistant and can be preserved by cooling through the underlying plate at a temperature which does not jeopardize its hardness. In particular, for example, Hardox steel is suitable as a building material for the Verschleissplatten. This wear plate 1 is - and this is very crucial - brought into the best possible thermal contact with the body 2 can be flowed through. Such Verschleissplatte 1, for example, 5 to 10 mm thickness is placed on the permeable body 2 and with the same positive and non-positive screwed, riveted, jammed or glued. In the wear plate corresponding holes 4 are provided for this purpose, so that the screw heads are flush with the Verschleissplattenoberfläche. To ensure good heat conduction from the plate 1 to the liquid-cooled steel structure 2, a suitable heat-conducting material 3 is inserted between the wear plate 1 and the liquid-cooled body 2 and clamped therebetween. This material 3 should compensate for any bumps and lead to a rich and intimate mechanical connection and heat connection of the two plates 1, 2. As such highly thermally conductive materials prove, for example, so-called highly heat-conductive soft silicone films. These are soft, by the filling with thermally conductive ceramics highly heat conductive silicone films of extraordinary elasticity. They prove to be special suitable to dissipate heat due to different tolerances and unevenness of two connectors over a greater distance to a housing or a heat sink. All the advantages of silicone as a base material come into play here, namely the high temperature resistance, the chemical resistance and the high electrical breakdown strength, although this latter property is not the focus of the present application.

Due to the high compressibility of the soft silicone films heat sources and heat sinks that have large bumps and tolerances, thermally optimally connected to each other. Due to the very good conformability of the silicone material, the contact surfaces are increased and the thermal connection is significantly improved. The applied pressure is low, and the very high elasticity provides additional mechanical damping. Because of their thermal properties, such soft silicone films have hitherto been used as ideal thermal solutions for use in electronic components on SMD printed circuit boards. Such soft silicone films can greatly reduce the overall thermal transfer resistance between two materials. Soft silicone films of this kind are available, for example, from Kunze Folien GmbH, Raiffeisenallee 12a, D-82041 Oberhaching (www.heatmanagement.com), where they are listed as highly heat-conductive soft silicone films KU-TDFD. They are available in different thicknesses: 0.5mm, 1mm, 2mm and 3mm. The thermal conductivity of this film material is 2.5 W / mK and the films can be used in a temperature range from -60 ° C to + 18O ⁰ C. Therefore, an employment between the wear plates and the cooled grate plate body of a refuse incineration grate is possible, because the cooled grate plates always remain at a temperature of less than 50 ⁰ C.

It is important for the use of the hard wear plates 1 namely, that their thermal capacity is not exceeded, which can be achieved by cooling by the liquid-cooled hollow iron plate 2, the operating temperature is around 50 ° C. So it's a sufficient one To ensure heat transfer from the Hardox wear plate 1 on the iron plate 2. This is now made possible by clamping a soft silicone film as described between the wear plate and the cooled grate plate, as shown in FIG. The soft silicone film 3 is placed on the grate plate 2 and the Verschleissplatte 1 placed on it. The Verschleissplatte 1 is folded forward and includes when placed on the grate plate 2 Whose whole, the kiln facing top and front.

In Figure 2, a grate plate is shown with three separate Verschleissplatten, said wear plates are juxtaposed and juxtaposed against each other and form a continuous grate surface except for the joints formed between. A division of the wear plate into several pieces is indicated on larger grate surfaces and facilitates the installation and removal in the grate, in which the individual Verschleissplatten pieces then less difficult.

The Verschleissplatte 1 is clamped to the grate plate 2. This can be seen, for example, with reference to FIG. For the clamping are about screw. As shown in the picture, the wear plate has several holes 4 with countersunk mouth. Through the cooled grate plate lead holes with the same flight. These can be realized, for example, by welding bushes 5 in the half-shells which seal the holes 4 in the surface of the half-shells. The half-shells are then welded together and the bushes 5, which engage with their ends in the holes 4 in the half-shell, are welded there sealingly with the surface of the half-shells. The wear plates are then bolted to the cooled grate plate 2 while clamping a soft silicone film 3 having corresponding holes. As shown in the picture on the right, countersunk screws 6 are inserted from above through the wear plate 1, through the soft silicone film 2 and through the bushings 5 in the grate plates 2 and clamped on the underside of the grate plate 2 with a lock nut 7. Thus, the wear plate 1 at several points down firmly on the grate plate. 2 tense and clamps the soft silicone film rich and form-fitting, so that an optimal heat transfer is guaranteed. Experiments showed that the heat transfer through the use of a soft silicone film is up to five times better so without inserting such a soft silicone film. The attachment of the wear plates can be done as an alternative to screw through rivets, or it will be used, for example, instead of screws as shown in the picture on the left bolts 8 with countersunk heads, which bolts 8 have a transverse slot 9 in the region of its end. It then only needs a wedge 10 by means of a hammer laterally driven into this slot 9. The release can then be done simply by a hammer blow on the opposite side of the wedge 10, which is even faster than a large lock nut to solve.

Instead of silicone films or soft silicone films and copper sheets can be used. Copper is a soft metal and also very good thermal conductivity. It is suitable in a similar manner for clamping between the water-cooled grate plates and the wear plates clamped therewith and, due to its softness, hugs the contours of the wear plate and the grate plate. All of the above applies equally to the provision of the side planks of a water-cooled grate. These side plates have hitherto also been made of water-cooled hollow bodies.

Figure 4 shows a sectional view across a liquid-cooled grate with two grids R (= right) and L (= left). The two grate webs R and L are separated by a central plank 11, which forms a Schürplanke both for the grate R and for the grate L. At the outer edges of the grate side planks 12,13 are present. The grate plates 2, at least every other, are designed to be movable and slide perpendicular to the drawing sheet plane along the central plank 11 and the side planks 12,13 back and forth. Thus, these side planks 12,13 and the central plank 11 are subject to wear. Through the use of wear plate on the surface, these wear plates under Clamping a soft Wärmeleitfolie with the planks 11, 12,13 are braced, it is possible to elegantly solve the wear problem without significantly worsen the desired heat dissipation. To revise such grate equipped with wear plates rust need only to be replaced, which is faster and cheaper, so to replace the entire grate plates 2 and planks 11, 12,13. Thus, the liquid-cooled grate is everywhere, where it comes into contact with firing material, and also everywhere, where it is subject to wear due to sliding friction, equipped with replaceable wear plates. At the same time, however, the cooling effect due to the liquid cooling is hardly affected, so that all their benefits still come to fruition.

5 shows the central guide rail 1 1 of Figure 4 in an enlarged view. The wear plates 1 are here made of two parts, which are joined together at the top 14 in the middle. From both sides they are secured with countersunk screws 6 on the plank 11, wherein they pinch an inserted heat-conducting film 3 below. In the lower part are the cooled and on its upper side also equipped with Verschleissplatten 1 grate plates 2 on the Verschleissplatten on the central plank 1 1 at.

FIG. 6 shows the one side guide rail 13 from FIG. 4 in an enlarged view. The wear plate 1 is pulled around here in one piece around the plank 13. Below it clamps a thermal pad 3 and it is screwed here with two countersunk screws 6 with the plank 13. In the lower of the wear plate 1 are the cooled and on its upper side also equipped with Verschleissplatten 1 grate plates 2 on the Verschleissplatte 1 at. The advantage of this rust-construction with separately applied Verschleissplatte 1 and soft heat conducting foil, for example, a soft silicone foil or a copper sheet for the heat transfer are the following: For maintenance, the individual grate plates or rust levels must not be removed and replaced, but you just replace the Wear plates 1 on the grate plates and on the same lateral limiting planks 11, 12,13, which therefore always remain in the system. The grate plates 2 and planks 11, 12,13 of iron keep up with their operating temperature of 5O ⁰ C and without mechanical wear for many years, so even decades. If only one wear plate 1 must be replaced on a grate plate, it costs a fraction of a whole conventional hollow grate plate. In addition, the replacement of a wear plate 1 is much faster than the replacement of a whole grate plate. If such has to be replaced, the cooling circuit must be interrupted and the plates must be emptied of the coolant. Then the individual grate plates can be lifted out of the grate in a relatively expensive way by means of a lifting device. The replacement panels must be redone in a relatively complex manufacturing process. On the other hand, if one only needs to replace wear plates 1, then the liquid-cooled rust need not even be emptied. All you have to do is loosen the nuts on the underside of the grate plate, and then you can lift the wear plates off the grate and replace them. New countersunk screws are used and the new wear plates are in turn clamped to the grate plates. The same applies to the lateral liquid-cooled planks of the grate. The replacement of the closure plates 1 is therefore much faster than the replacement of whole grate stages, and the preparation of new liquid-cooled grate plates as practiced previously eliminated altogether. In addition, the heat distribution is greatly improved thanks to this inserted Wärmeleitfolie. The heat is therefore everywhere uniformly removed from the grate surface, that is, from the wear plates and these are largely the same hot over their entire surface. The advantages of this design presented here are therefore very obvious.

Claims

claims

1. A liquid-cooled grate comprising a plurality of grate plates (2) through which a liquid can flow and side planks (11, 12, 13) whose surfaces are each equipped with one or more wear plates (1) which conduct heat-conducting with the liquid-cooled grate plate (2) the side plank (11, 12, 13) are connected, characterized in that in order to obtain the heat transfer from the wear plates (1) to the liquid - cooled grate plates (2) and side planks (11, 12, 13) between the wear plates (1) and the liquid-cooled grate plates (2) and side planks (11, 12, 13) are each clamped in a highly heat-conducting film and the wear plates (1) are detachably connected to the liquid-cooled grate plates (2) and side planks (11, 12, 13).

2. Liquid-cooled grate according to claim 1, characterized in that the highly heat-conductive film (3) consists predominantly of silicone.

3. Liquid-cooled grate according to claim 1, characterized in that the highly heat-conductive film is a soft silicone film (3).

4. Liquid-cooled grate according to claim 1, characterized in that the highly heat-conductive foil is a copper sheet.

5. Liquid-cooled grate according to one of the preceding claims, characterized in that its surfaces are equipped with wear plates (1) made of Hardox, which by clamping a highly heat-conducting film (3) heat-conducting with the underlying liquid-cooled grate plates (2) and side planks (11, 12 , 13) are connected.

6. Liquid-cooled grate according to one of the preceding claims, characterized in that its surface, that is to say the surfaces of the grate plates (2) and side planks (11, 12, 13) are equipped with wear plates (1) in that they are secured by means of screw connections (6, 7) are connected to the grate plates (2) or side planks (11, 12, 13).

7. Liquid-cooled grate according to one of claims 1 to 6, characterized in that its surface, that is, the surfaces of the grate plates (2) and side panels (11, 12,13) are equipped with Verschleissplatten (1) by the same by means of rivets with the grate plates (2) or side planks (11, 12,13) are connected.

8. Liquid-cooled grate according to one of claims 1 to 5, characterized in that its surface, that is to say the surfaces of the grate plates (2) and side planks (11, 12, 13) are equipped with wear plates (1) in that they are clamped by means of clamping Connections (8-10) with the grate plates (2) or side planks (11, 12,13) are connected.