EP0277053A1 - Furnace grate with transversal fire bars which are connected to each other at their front side - Google Patents

Abstract

A hearth grate comprises a succession of transverse bars which are alternately fixed and movable with a reciprocating movement, said bars being formed by disposing in side-by-side relationship at vertical lateral faces elements which are generally rectangular, with a projection portion at the junction of a frontal face and a dorsal face and in the dorsal face blowing orifices opening in said projection portion. The elements are held by the insertion into openings provided in the frontal faces of limbs of a fastener. The fastener comprises a transverse portion which is disposed in set-back relationship with respect to the frontal faces. Plate portions are welded over the openings to retain the fastener.

Description

The invention relates to a hearth grate, for supporting a mass of burning solids, in particular urban waste, comprising, on a downward slope from an upstream loading zone to a downstream ashtray, a succession of transverse bars, alternately fixed and movable back and forth longitudinally, and having on the top a dorsal face to support the mass and a front face in sliding support on the dorsal face of an upstream bar, each bar consisting of a plurality of elements generally rectangular contiguous along vertical side faces.

This type of grid, where the faces of the elements devolved to the thrust are turned upstream, to oppose the rapid descent of combustible solids, and cause mixing of the mass, have been abundantly described in the state of the technique since patent US-A-2,250,067, filed in 1939. Since then, improvements have been made, aimed in particular at the provision of blowing orifices which pass through the elements to bring combustion air to the mass in combustion , from blowing boxes located below the grid.

Patent document FR-A-2 574 160 describes a recoil hearth grate which comprises elements of bars provided, at the connection of the front face and the dorsal face, and on the latter, a transverse faceted projection, with air blowing holes made in a rear facet of the projection, so as to look downstream, and channel air jets from below the grid into the mass of combustible solids, in an upward direction with an angle of about 15 ° on the horizontal.

This patent document also describes means for keeping the elements of adjoining bars in alignment, these means consisting of transverse pins which pass through holes made in the lateral faces at the location of the projections.

In fact, it is essential, for the stability of the combustion settings in particular, that the blowing air reaches the mass in combustion only through the blowing orifices. It is therefore necessary to prevent the rod elements from being lifted by the solids in combustion when they are supported by the lower edge of their front face on the dorsal face of the element located immediately upstream. It will be recalled that the bars are held in place by their weight, and held by the rear end of their lower face on a cross member, which engages in a transverse groove formed in this lower face. The cross member is alternately fixed to the general grid frame, and fixed to a moving frame back and forth.

The purpose of dividing the bars into transversely aligned elements is, on the one hand, to give the bar relative flexibility, and on the other hand to facilitate the assembly and disassembly of the grid by constituting elements of dimensions and manageable weight.

But the counterpart of the fractionation is that the risks of lifting of the elements by the mass in combusion are increased; it is therefore recommended to hitch the bar elements together, so that the total weight of the bar opposes the lifting.

The solution recommended by FR-A-2 574 160 has drawbacks, however. The pins can only be inserted into the holes provided for this purpose in the side faces of the elements away from the location of the bar on the grid, because the grid is laterally limited by hearth walls. The bar must be put in place assembled, which involves manipulations of the entire bar. The dismantling in elements also supposes that the bar, removed whole from the grid, is carried away to uncover the elements. This is particularly annoying when it is only necessary to disassemble a few elements, for example to replace them if they appear defective, because it is then necessary to handle all the bars, whole, which comprise at least one defective element.

To overcome this drawback, the invention proposes a hearth grate, to support a mass of burning solids, in particular urban waste, comprising, in a downward slope from an upstream loading zone to a downstream ashtray, a succession of transverse bars, alternately fixed and movable back and forth longitudinally, and having on the upper side a dorsal face for supporting the mass, and a front face in sliding support by a lower edge on the dorsal face of an upstream bar, each bar consisting of '' a plurality of generally rectangular elements in abutment along lateral sides, coupling means, arranged near the front faces, ensuring the maintenance in transverse alignment of the plurality of elements, characterized in that said coupling means include C-shaped staples with two parallel branches joined by a perpendicular crosspiece, each staple being able to be arranged in a bridge between two joined elements s, with each of its branches respectively engaged in a housing formed in the front face of one and the other of the adjoining elements.

It is understood that thus, when mounting the grid, it is only necessary to handle separate elements, the positioning of the staples being done last. In addition, later, to move or replace an element, it suffices to remove the two staples which attach it to the elements placed side by side, or a single staple if it is a border element.

Preferably, the housings are symmetrical with respect to a median plane parallel to the lateral faces, so that the adjacent housings of two adjoining elements are arranged symmetrically with respect to the plane of the joined lateral faces.

According to preferred arrangements, the elements include notches which connect the staple branch housings to the adjacent lateral face, to make room for the staple crosspiece. This crosspiece can be engaged in the recesses set back from the front face. The notches can be extended by slits, along the branches. Plates can be welded above the housings to prevent the staple from coming out of the housing, but these platelets must not bridge between the elements, to keep play possibilities.

Preferably, the elements have transverse projections on their dorsal face, at the connection with the front face, with a rear facet where the blowing orifices open out.

• la figure 1 représente, en perspective éclatée, les moyens d'attelage à agrafe selon l'invention ;
• la figure 2 est une coupe suivant le plan II-II de la figure 3 ;
• la figure 3 est une coupe suivant le plan III-III de la figure 2 ;
• la figure 4 est une perspective d'un élément de barreau, dans la zone à l'angle des faces frontale et latérale ;
• la figure 5 est une vue frontale de la zone d'accolement de deux éléments de barreau ;
• la figure 6 est une vue latérale de l'avant d'un élément de barreau, dans le plan VI-VI de la figure 5 ;
• la figure 7 est une vue de dessus d'une grille de foyer selon l'invention.

The characteristics and advantages of the invention will become apparent from the description which follows by way of example, with reference to the accompanying drawings in which:

• Figure 1 shows, in exploded perspective, the clip coupling means according to the invention;
• Figure 2 is a section along the plane II-II of Figure 3;
• Figure 3 is a section along the plane III-III of Figure 2;
• Figure 4 is a perspective of a bar member, in the area at the corner of the front and side faces;
• Figure 5 is a front view of the adjoining area of two bar elements;
• Figure 6 is a side view of the front of a bar member, in the plane VI-VI of Figure 5;
• Figure 7 is a top view of a fireplace grate according to the invention.

The general structure of the hearth grate will be assumed to be known, in particular for burning urban waste, which will be described very succinctly here, referring for details for example FR-A-2,574,160, this document. constituting a state of the art close to the present invention.

It will be recalled that this kind of hearth grate comprises, in a downward slope from an upstream loading zone to a downstream ashtray, a succession of transverse bars, alternately movable back and forth longitudinally and having on the upper side of the grate a dorsal face to support the mass, and a front face in sliding support by a lower edge on the dorsal face of an upstream bar. Each bar comprises a plurality of generally rectangular elements placed side by side along vertical lateral faces.

According to the embodiment chosen and shown in Figures 1 to 6, two bar elements 10 and 11, of which only the regions of interest are shown, are joined by side faces 109 and 119 respectively. These side faces are vertical on the assembled grid , and perpendicular to a front face 101, 111, respectively, as well as to a dorsal face 102, visible on the element 10 in only FIG. 6. The front faces 101 and 111 comprise two flaps 101 a , 101 b for l element 10, and 111 a , 111 b for element 11.

The lower panel is strongly inclined relative to the plane of the dorsal face 102 (see FIG. 6), while the upper panel is inclined at approximately 45 ° on the plane of the dorsal face 102.

The lower pan 101 a, 111 terminates at its lower part, by a flange 100, 110 by which the element 10, 11 rests on the dorsal face of the element located immediately upstream.

The dorsal face 102, at its connection with the upper face 101 b of the front face, is surmounted by a projection 103 of trapezoidal section, with a front facet 103 a in continuity with the upper face 101 b , an upper facet 103 b substantially parallel to the dorsal face 102, and a rear facet 103 c . In this rear facet and perpendicular to it, holes are made supply air 103 d .

When the elements are in place on the grid, the orifices 103 d are directed downstream, with their axes sloping upwards at approximately 15 ° on the horizontal. The blowing orifices 103 are supplied with air by at least one box located below the grid.

As one bar in two is movable back and forth its projection 103 will approach and move away alternately from the projection of the upstream element and that of the downstream element so as to produce a mixing of the solid mass in combustion. The relative inclinations of the front face 101 and the rear facet 103 c are such that a block of fuel caught between these surfaces is lifted when they approach.

The orientation of the blowing orifices, slightly inclined to the horizontal, reduces the importance of the fly ash entrained through the boiler tubes.

It is clear that the regularity of combustion depends on the adjustment of the blown air-oxidant, so that it is of primary importance that an element cannot be lifted from its support on the dorsal face of the upstream element.

To link together the elements of the same bar, so that each of the elements is held by the total weight of the bar, the coupling means are used which form the precise object of the present invention.

In each of the front faces 101, 111, and more exactly in the lower sections 101 a , 111 a of these faces are formed near the lateral abutment faces 109, 119 of the housings 104, 114, of rectangular section, which can receive branches 20, 21 of a C 2 staple, the two branches 20 and 21 being joined by a cross member 22. This staple is of uniform thickness and its branches 20 and 21, as well as its cross member 22 have rectangular sections.

The housings 104, 114 extend, towards the abutment face 109, 119 by notches 108, 118, such that the crosspiece 22 of the clip 2 can penetrate to come set back from the lower pan 101 a, 111a of the front face 101, 111, while the branches 20 and 21 penetrating respectively in the housings 104 and 114.

It will be understood that the housings 104, 114 are formed perpendicular to the lower sections 101, 111 has end faces 101, 111 and the staple 2 is oriented parallel to the lower edges 100, 110.

It will be noted that a clearance is provided between the housings 104, 114, the notches 108, 118, and the clip 2 with its branches 20 and 21 and its cross member 22, to allow clearances of the order of a millimeter in all directions. It will be remembered that all of these organs are made of refractory, fragile cast iron.

Furthermore, as seen above in Figures 3 and 6, the notches 108 are extended by slots 105 which extend to the bottom of the housing 104, which provides retaining projections 106 and 107 for the branch of clip (see Figure 4).

This arrangement makes it easier to extract a staple stuck in the housing, by breaking the crosspiece to introduce a hook behind the stuck branch.

It will be understood that the housings 104, 114 and the notches 108, 118 are arranged symmetrically with respect to an abutment plane materialized by the lateral faces 109, 119. Like the elements 10, 11, all have the same structure, in each element , in the vicinity of the lateral faces, there will be two housings 104 and notches 108, arranged symmetrically with respect to a median plane of the element parallel to the lateral faces.

When the clip 2 is in place, two rectangular plates 30, 31 are welded onto the opening of the housings 104 114, so as to trap the clip in its housings. The welding of the wafers is done by performing arc welding points. Because of the fragility of the cast iron, a few chisel blows will blow up the plates 30, 31, to release the clip 2.

It may be advantageous to constitute fiber mats at the bottom of the housings 104 and 114, so that the ends of the branches 20 and 21 are stopped while retaining a possibility of play between the elements 10, 11.

FIG. 7 represents a longitudinal portion of the grid, comprising transverse bars 200, 210, 220, 230, 240, 250, 260, each bar comprising several elements which are referenced with the digits of the tens and hundreds of the bar to which they belong, the number of units being 1, 2, 3 or 4, in order from bottom to top.

The upstream of the grid is on the left of the figure and the downstream on the right.

to avoid the formation of extended longitudinal joint lines, the successive elements are offset laterally by thirds of width. Elements of a third and two thirds of width are arranged at the ends of the bars 210,220,240,250, to achieve this offset.

It will be noted that the element 242 is missing, which reveals the dorsal face of the upstream element 232 in its entire extent.

Note that the bar elements have a projection on the dorsal face at the connection with the front face. The projections are referenced by the reference of the element followed by the letter a. In the rear facet of the projections ... a open blowing orifices referenced by the reference of the element followed by the letter b . To make the figure clearer, the projection references ... a only appear for the bar 200, and only one blowing orifice is referenced per element in the bar 200.

Of course, the invention is not limited to the examples described, but embraces all the variant embodiments, within the scope of the claims.

Claims (10)

1. Hearth grate, to support a mass of burning solids, in particular urban waste, comprising, on a downward slope from an upstream loading area to a downstream ashtray, a succession of bars (200, 210, 220, 230, 240 , 250, 260) transverse, alternately fixed and movable back and forth longitudinally, and having on the upper side a dorsal face (102, 112) for supporting the mass, and a front face (101, 111) in sliding support by a lower edge (100, 110) on the dorsal face of an upstream bar, each bar consisting of a plurality of elements (10, 11) generally rectangular in abutment along lateral sides (109, 119), means d coupling (2), arranged near the front faces (101, 111) ensuring the maintenance in transverse alignment of the plurality of elements, characterized in that said coupling means comprise C-clips (2) with two branches (20, 21) parallel joined by a crosspiece (22) perpendicular, each clip (2) able to be arranged in a bridge between two elements (10, 11) joined together, with each of its branches (20, 21) respectively engaged in a housing (104, 114) formed in the front face (101, 111) of one and the other of the joined elements (10, 11). 2. Grid according to claim 1, characterized in that the two housings formed in the front face (101) of each element (10) in order to keep it aligned with similar elements placed on either side of it, are symmetrical with respect to a median plane parallel to the lateral faces (109). 3. Grid according to one of claims 1 and 2, characterized in that the bar elements (10, 11) have notches (108, 118) connecting each of the housings (104, 114) to the lateral face (109, 119) neighboring, these notches (108, 118) being able to receive the crosspiece (22) of staple (2), in bridge between two elements (10, 11). 4. Grid according to claim 3, characterized in that the notch (108) is deep enough for the crosspiece (22) of staple to come back from the front face (101, 111) of the contiguous elements (10, 11). 5. Grid according to one of claims 3 and 4, characterized in that a slot (105) extends the notch (108) over the entire depth of the housing (104), the height of this slot (105) being less to the thickness of the staple branches (20, 21) (2). 6. Grid according to any one of claims 1 to 5, characterized in that the branches (20, 21) and the crosspiece (22) of staple (2) have rectangular sections with similar thicknesses. 7. Grid according to claim 4, characterized in that plates (30, 31) are welded flat on the front faces (101, 111), each covering at least partially a housing (104, 114) of staple branch , without overflowing on the front face of the adjacent element. 8. Grid according to any one of claims 1 to 7, characterized in that the bar elements (10) have on their dorsal face (102) at the connection with the front face (101) at least one transverse projection (103) with a rear side, facing downstream, where at least one blowing channel (103 d ) opens through the element. 9. Grid according to claim 8, characterized in that the blowing channels (103 d ) have, in the grid, an axis directed longitudinally downstream in ascending, the slope of this axis being closer to a horizontal than of a vertical. 10. Grid according to claim 9, characterized in that the slope of the blowing channel axis (103 d ) is approximately 15 °, the rear facet (103 c ) of the projection (103) being perpendicular to this axis.

Images