METAL-CERAMIC COMPOUND GRATE BAR FOR WASTE INCINERATION

Abstract

A grate bar configured to include a reinforcement structure of sheet metal and structured to be manufacture at a reduced cost while exhibiting reduced wear and enhanced resistivity to hear and corrosives. A metal-ceramic compound grate (for example—an incinerator grate) utilizing such a grate bar. An incinerator and a cooling grate including such grate bar.

Claims

1. A grate bar comprising: a hull with a bottom and side walls, said bottom and first and second side walls made of first sheet metal, at least one of the first and second side walls containing a recess; a support structure inserted into said hull to form compartments between said hull and said support structure, the support structure made of second sheet metal; the compartments containing a ceramic material, wherein the support structure contains at least two pieces of the second sheet metal, each of the at least two pieces having first and second edge surfaces; wherein a first edge surface of the at least two pieces faces the first side wall while the second edge surface of the at least two pieces faces the second side wall; and wherein at least one of said at least two pieces engages in the recess.

2. The grate bar of claim 1, wherein the second sheet metal has recesses configured to establish fluid communication between at least two of said compartments, wherein at least one of the recesses is at least partially filled with said ceramic material and wherein the at least two of said compartments are filled with said ceramic material at least in part.

3. A grate bar of claim 1, further comprising a first top surface formed by said ceramic material, said top surface being formed from said ceramic material.

4. A grate bar of claim 3, further comprising at least a second top surface in a rear end section of the grate bar, said second surface comprising a surface of a metal plate positioned on edge surfaces of the first and second side walls of said hull.

5. A grate bar of claim 4, wherein at least one of (i) the metal plate and (ii) the first and second side walls has a protrusion, and at least one of (a) the first and second side walls and (b) the metal plate has a recess complementary to said protrusion, said protrusion engaging into said complementary recess.

6. The grate bar of claim 4, wherein, when the second top surface is positioned horizontally, the first top surface of ceramic material is substantially parallel, to the second top surface and at a level below said second top surface.

7. The grate bar of claim 1, wherein each of the at least two pieces of the second sheet metal has a slit dimensioned to accommodate another of said at least two pieces, and wherein a first of the at least two pieces of the second sheet metal is inserted into the slit of a second of said at least two piece to affix the first and second of the at least two piece to one another.

8. The grate bar of claim 1, wherein, when the support structure is inserted into the hull, at least one piece, from the at least two pieces of the second sheet metal, extends slantingly with respect to a side wall from the first and second side walls, said at least one piece having a cut through an edge surface thereof and being partially bent along the cut to form a bent portion and a protrusion with respect to the bent portion; wherein the protrusion is engaged in to a recess of the closest of the first and second side walls.

9. The grate bar of claim 1, further comprising at least one threaded insert element is connected to and supported by at least one of said first and second side walls.

10. The grate bar of claim 1, further comprising a metal front plate extending below a bottom of the hull.

11. The grate bar of claim 10, wherein the metal front plate is bent in a u-shaped fashion to form a first leg and a second leg, the first leg being longer than the second leg, with the first leg being attached to front edge surfaces of the first and second side walls and the second leg supporting a bottom of the hull.

12. The grate bar of claim 1, further comprising at least one combustion air channel, with an inlet and an outlet, configured to deliver combustion air to at least one of a top portion of the grate bar and to an area in front of the grate bar.

13. A grate bar of claim 1, wherein the support structure comprises at least one piece of sheet metal forming a tubular section.

14. An incinerator comprising a grate bar of claim 1.

15. A cooling grate comprising a grate bar of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In the following, the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment and with reference to the drawings.

[0047] FIG. 1 shows an isometric view of a grate bar,

[0048] FIG. 2 shows a side view of the grate bar of FIG. 1,

[0049] FIG. 3 shows a longitudinal section (along plane B-B indicated in FIG. 4) of the grate bar of FIG. 1,

[0050] FIG. 4 shows a top view of the grate bar of FIG. 1,

[0051] FIG. 5 shows a front view of the grate bar of FIG. 1, and

[0052] FIG. 6 shows a cross section (along plane A-A indicated in FIG. 2) of the grate bar of FIG. 1,

[0053] FIG. 7 shows a longitudinal section like FIG. 3, but of a grate bar with gas channels.

[0054] Various modifications and alternative forms of the embodiments are within the scope of the present disclosure, specific embodiments of the invention shown in the drawings provide but examples. These will be now described in detail. It should be understood, however, that the drawings and detailed description are not intended to limit the scope of the invention to the particular disclosed form(s), but to the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION

[0055] The grate bar 1 in FIG. 1 has a metal structure of a hull 10 and support structure 20. The hull has a bottom 13 and side walls 11, 12, each preferably of sheet metal. The front of the hull 10 is formed by a front wall 15. The side walls 11, 12 may be congruent, as shown. The bottom 13 and the side walls 11, 12 are formed from a single piece of sheet metal by cutting the sheet metal and folding the sheet metal. Alternatively, the side walls 11, 12 and the bottom 13 may be cut separately and be connected by any appropriate method, e.g. welding. The hull 10 and the support structure 20 are enclosed in a ceramic body 5 made of ceramic material 5, which is indicated only by dashed lines (otherwise the support structure and parts of the hull would be hidden). The grate bar 1 has a recess 19 at the rear and of its down facing side to engage with a cross beam (not shown) of an incinerator grate.

[0056] The hull 10 has a front section and a rear section. The rear section may be covered by a metal plate 14 being supported by the side walls 11, 12. As shown in FIGS. 1, 2 and 3 the side walls 11, 12 and the metal plate 14 may engage with each other, to thereby ease assembly of the metal structure and to enable transfer of shearing forces between the side walls 11, 12 and the metal plate. In the depicted example the side walls 11, 12 have protrusions 111, 121 each engaging into a recess 141 of the metal plate 14 and thus form fittingly connecting the side walls 11, 12 and the metal plate 14. Of course the side walls 11, 12 could as well have recesses into which the metal plate 14 is inserted or into which protrusions of the metal plate 14 engage.

[0057] The front plate 15 of the hull resembles or can be considered to be a profile with a first leg or portion 151 being attached to the side walls 11, 12 front narrow sides (edge surfaces) and/or the bottom's 13 front narrow side (or edge surface). The first leg or portion 151 extends below the bottom, there the front plate 15 is bent to provide an intermediate leg or portion 152 (second leg or portion), with a middle section being at least approximately parallel to the bottom. From the middle section a third leg or portion 153 is bent upwards to support the bottom 13 at its lower facing side.

[0058] Inside the hull 10 is a support structure 20 of sheet metal pieces 30. Each sheet metal piece 30 extends between the side walls 11, 12, i.e. the right and left narrow sides of the pieces 30 face towards the respective side wall 11, 12. However, the pieces 30 do not necessarily extend orthogonally between the side walls but may preferably extend slantingly (as depicted). Only to avoid any confusion slanting is to be understood as ‘in an oblique angle’ as explained in more detail above. Every piece 30 forms an angle opposed to its adjacent pieces. Thus, two adjacent pieces 30 form opposed angles with the side walls 11, 12.

[0059] The pieces 30 are assembled to form a pair of engaging pieces 30 as can be best seen in FIG. 1, FIG. 4 and FIG. 6. To this end, each piece 30 has a slit 31 into which the other piece 30 of the pair is inserted. The other piece 30 has a complementary slit 31 to accommodate the remaining part of the first of said pieces. In the top view (FIG. 4) each pair of sheet metal pieces 30 resembles a Saint Andrew's cross.

[0060] As can be seen best in FIG. 6, the pieces 30 of each sheet or at least some of them each may have two cuts 32 from the left and right narrow sides towards their respective other narrow side. Thus, at each side of the piece 30 may be an upper sheet metal part 33, i.e. the material of the piece 30 above the cut. These parts can be bent towards their respective next side wall 11, 12 and thereby form protrusions 33 which can engage into recesses 113, 123 of the side wall 11, 12. The pieces 30 of sheet metal can thus simply be hung into the hull 10 when manufacturing the grate bar. Additionally the pieces 30 may have protrusions 36 (FIG. 2 and FIG. 6) extending from their lower narrow side into recesses 137 (FIG. 6) of the bottom 13.

[0061] The hull 10 and the pieces 30 forming the support structure 20 may have through holes 114, 124, 134, 304 to enable a ceramic slip to fill each compartment of the metal structure and to provide a reliable engagement between the sheet metal and the ceramic body by positively-locking the (later) ceramic body and the sheet metal structure (FIG. 1 to FIG. 4 and FIG. 6).

[0062] The hull 10 and the support structure 20 may be assembled and subsequently provided into a negative mold of the grate bar 1. The mold is subsequently filled with a ceramic slurry, usually referred to as ceramic slip. After initial hardening of the ceramic slurry, the cured grate bar can be removed from the mold, further dried (if necessary) and fired. Thus, the form does not need to withstand high temperatures and can be made of correspondingly cheap material and/or may be reusable.

[0063] The front plate 15 may be replaceable as shown in FIG. 1 to FIG. 5: The front plate 15 is bolted using bolt 16 to a cross piece 35 supporting a nut 17 into which the bolt 16 engages. In the depicted example, the cross piece 35 is a sheet metal plate, being inserted in the hull. The cross piece engages with the hull like the sheet metal pieces 30. Alternatively, the cross piece could be a cross beam connecting the side walls 11, 12 or a profile.

[0064] In case the front plate is worn off, the bolt can be released and the front plate 15 can be replaced by a new or at least less worn front plate 15 which is bolted to the cross part 35. The cross part 35 extends like the pieces 30 in the hull 10, but different to said pieces 30 it extends preferably orthogonally to the longitudinal direction of the grate bar 1.

[0065] As can be seen in FIG. 2, threaded insert elements 40 are attached to recesses in the hull, in particular in the side walls 11, 12 and enable to connect multiple grate bars 1 to form a row of grate bars.

[0066] The grate bar as shown in FIG. 7 is almost identical to the grate bar as depicted in FIG. 1 to FIG. 6, accordingly the description referring to FIG. 1 to FIG. 6 can be read on FIG. 7 as well, But different from the grate bar of FIG. 1 to FIG. 6, the grate bar as shown in FIG. 7 has gas channels 50 for providing a gas, e.g. air from below of the grate bar to the top of the grate bar. The gas channels are shown only schematically. Gas flowing through said gas channels 50 may be used for processing the matter residing on the grate bar, e.g. as coolant for cooling cement clinker or as oxygen source for waste incineration. The number of gas channels is not limited to the depicted number, any number may be chosen (“at least one”). A gas channel can be formed in the grate bar by first providing corresponding recesses in the support structure and by insertion of a positive form as placeholder of the later gas channel(s) 50 in the hull 10 and the support structure 20. Subsequently, the hull 10 with the support structure 20 and the positive form is inserted into a mold and ceramic slip may be inserted into the mold. After drying of the slip, the positive form is removed from the green body. In the simplest form, the positive form, i.e. the placeholder liquefies when firing the green body to convert it into ceramics and pours out of the grate bar 1. Other techniques for removal of the placeholder(s) may be applied as well.

[0067] It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide a grate bar for a waste incinerator grate and as well for a clinker cooler grate. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.

LIST OF REFERENCE NUMERALS

[0068] 1 grate bar [0069] 5 ceramic body ceramic material [0070] 10 hull [0071] 11 side wall [0072] 111 protrusion [0073] 113 recess [0074] 114 through hole [0075] 12 side wall [0076] 121 protrusion [0077] 123 recess [0078] 124 through hole [0079] 13 bottom [0080] 134 through hole [0081] 137 recess [0082] 14 metal plate [0083] 141 recess [0084] 15 front plate [0085] 151 first leg or portion [0086] 152 second leg or portion [0087] 153 third leg or portion [0088] 16 bolt [0089] 17 nut [0090] 19 recess [0091] 20 support structure [0092] 30 piece of sheet metal [0093] 31 slit [0094] 32 cut [0095] 33 protrusion of left or right narrow side/upper part [0096] 35 cross piece, e.g. a plate of sheet metal, a cross beam, a profile etc. [0097] 36 protrusion of lower narrow side [0098] 304 through hole [0099] 40 threaded insert element [0100] 50 gas channel