FR2463894A1 - Solid fuel grate with vibrating grid - has water cooling pipes under grid supported on antivibration mountings - Google Patents

Abstract

The hearth consists of a grid (1), mounted on a slope and set to vibrate under the influence of a vibrator (12). The grid is supported on a chassis (2) which has cross beams (15) fixed through shock absorbers. The grid is fitted with internal water pipes (40) supplied from a header box (4) through the pipes (45) with a lower header (3) and drain connections (39). The chassis is mounted on flexible mountings (7,8) at each corner of the box.

Description

 The invention relates to an inertia hearth for solid fuels comprising a horizontal or inclined grid subjected to vibrations and / or tremors generated by a vibration generator and / or directed tremors, with a slight oblique deviation upwards, substantially in the direction desired progression of solids on the grid and having a grid support frame.

Many devices of the type mentioned above are contacted; particular mention will be made of French patents or patent applications 1,377,257, 1,573,678 and 2,385,033.

Experience has shown that it is very difficult to avoid
and poor mechanical performance of these parasites, causes of accelerated wear / of the equipment. When, in addition, the known devices include fluid circulation tubes, such as water, we must face difficult problems of flexible connection and therefore sealing, as is the case for French patent 1 377,257.

Furthermore, the known devices cannot be reconciled with a controlled distribution of the combustion air through the grate.

 The object of the invention is to propose a new inertia hearth which does not have the above drawbacks and which can be adapted, with a minimum of modifications to all types of existing ovens, and in particular to refuse combustion ovens, in with good longevity and offering new advantages, such as a controlled distribution of combustion air through the grate and no transfer of dynamic forces in the oven structures, the hearth resting independently on the floor.

This object is achieved, according to the invention, by the fact that the chassis is rigid and it is made up of a vibrating and / or jerking chassis, elastically mounted, on which is directly mounted the vibration generator and / or jerks and the grid. is fixed in contact with the chassis at at least two points, at least one of which includes a friction damper. According to the invention, we therefore deviate completely from the usual practice of vibrating the grid relative to a fixed chassis , and the hearth is given a general structure quite similar to that of a vibrating or shaking screen, but with means allowing a relative expansion play between the chassis and the grid, while preventing the grid from vibrating with respect to the chassis , so that the frame and the grid constitute a single inertial assembly which cannot be deformed to the vibrations generated and which excludes resonance vibrations at the natural frequency of the grid.

It is in accordance with the invention that with a grid constituted by a plurality of parallel bars arranged in the direction of progression of the solids, the bars are each linked to the chassis by at least one damping connection means constituted by a fastening device. with friction ensuring a friction force greater than the force of action or reaction by inertia of the bars to be driven or driven in vibrations and / or jolts. In this way the assembly can support the relative displacements necessary to avoid the stresses due to thermal expansions, but it behaves dynamically like a rigid body with a single center of inertia free of its own resonance. various components.

 it is advantageous that the chassis comprises upper crosspieces by means of which, taken two by two, each bar is linked by a friction damper.

 It is also advantageous that each bar extending from one end to the other of the grid is constituted by several elements arranged contiguous end to end and of which one end, at least, is frictionally linked to the chassis by means of the sleepers. In this way the bars are easily mounted and dismountable and light to handle.

It is advantageous for each bar to have a general inverted U shape and for the bars to be joined in parallel and to have grooves on their junction faces constituting air intake vents.

 It is in accordance with the invention that the bars have attachment ears, by which they are clamped in contact with the chassis by means of connecting rods, constituting tie rods, and springs with large clamping force, such as stacks of Belleville washers.

According to a preferred embodiment, the chassis is constituted by a partitioned box for supplying and distributing combustion air, with upper crosspieces arranged at least in line with each partition.

 In a hearth in which are arranged under or in the grid bundles of fluid circulation tubes parallel to the direction of progression of the solids, and connected to at least one of the ends of the grid to a collector, it is in accordance with the invention that at least at one end the collector mounted mobile and that this collector and / or the connected ends of the fluid circulation tubes are connected to the chassis by a friction device.

 It is advantageous for the hearth to be associated with a programmed and / or programmable digital control for intermittent start-up of the generator device and vibrations and / or shaking and for the start control for the generator device to be associated with a blow-out control command. air through the grid and vice versa. In this way a good homogenization of the layer in ignition is obtained, which is important in particular in the case of combustion of garbage or waste, better elimination at the end of combustion, as well as the limitation of the flight of incandescent particles or not.

The invention also offers the advantage of allowing easy elimination by vibrations and / or shaking of the solid particles having passed through the grid. For this purpose, it suffices that the bottom of the box is shaped as a collector for transporting and discharging solid particles, since it is subjected by construction to vibrations or jolts giving a suitable direction of progression to any particle collected. In this case, any transverse partitions must be open in their zone adjoining the bottom of the box.

 Other characteristics and advantages of the invention will emerge from the description, which will be given below only by way of example, of embodiments of the invention. For this purpose, reference is made to the accompanying drawings.

Figure 1 is a perspective view of a fireplace according to the invention.

 Figure 2 is a schematic view on a smaller scale to show the direction of action of vibrations and / or shaking.

FIG. 3 is a perspective view on a larger scale of a bar element for a grid of FIG. 1 with tubes of water for cooling the grid.

 Figure 4 is an equivalent view for an air-cooled grid.

Figure 5 is a longitudinal view showing the mounting of a bar and its associated water tube.

FIG. 6 is a detailed exploded view - of the mounting device - of the bar element of FIG. 3.

An inertia hearth according to the invention consists, as a whole, of a rigid box 2 elastically mounted by supports 6 on resorts 7 fixed to the ground by the inter
sealed to the ground.

middle of seat plates 8 / On the box 2, two exciters 12 of vibrations or jolts are fixed. The top of the box 2 is occupied by a grid 1, the constitution and method of attachment of which will be explained in more detail, and whose inclination relative to the horizontal makes an acute angle 9 (, so that the grid is inclined at the bottom from right to left in FIGS. 1 and 2. The general direction of the vibrations or tremors makes an acute angle with the grid plane and is directed left upwards in FIGS. 1 and 2. Your directed vibrations printed
to the box are so that they facilitate the desired progression of the fuel from right to left according to FIGS. 1 and 2. To ensure its rigidity, the box comprises upper cross members 15 which at the same time serve to support the grid 1, and, to ensure a suitable air distribution under the grid, the box 2 comprises transverse partitions 9 delimiting compartments supplied with air by openings 14 made in the side walls of the calisson. These openings 14 can receive pulsed air through flexible connections.

Depending on their lateral or lower position, these openings also receive a suitable protection device against falls of sieved products in the flexible connector.

 The bars of the grid 1 are made up of longitudinal elements end to end and side by side as shown in FIG. 3, for cooling the grid by water tubes and, in FIG. 4, for cooling the grid. by air.

 Each bar element 20, shown in FIG. 3, has a general shape of an inverted U carrying, in the vicinity of each of the ends of its wings 21, a stirrup 22 projecting downward constituting an ear 23 with two notches 24. In FIGS. 5 and 6, it can be seen that two notches 24 transversely opposite can receive a lifter 25 for a tie rod 26 on which a spring box 27 can be mounted for Belleville washers 28 which can be tightened by a pressure washer 29, a nut 30 and a lock nut 31 on the threaded end 32 of the tie rod 26. Before engaging the spring box 27 on the tie rod 26, the latter is introduced into a through hole 33 of a horizontal wing 34 of an angle iron 35 extending along the cross member 15 to which it is integral. Between the two wings 21 of the inverted U-shaped bar is disposed a water circulation tube 40, which, except to the right of the leftmost cross member 15, can be blocked between grid element 20 and cross 15 and whose the assembly will be explained later in more detail. The length of the longitudinal elements 20 corresponds to the spacing between crosspieces 15, so that the ends of two end-to-end elements join in line with one of the crosspieces 15 and that each crosspiece maintains, by their ears 23, the respective ends of each of these two elements.

 The bars 20, having a general shape of an inverted U, however have two longitudinal edges 36 with vertical plane faces extending transversely and symmetrically beyond the wings 21 so that two bars side by side touch by a plane of vertical joint of the edges 36. In the edges 36 are provided vertical grooves 37 extending on the outer face of the wings 21 to constitute air intake vents through the grid formed by the bars which are joined longitudinally and in transverse direction. The air intake thus produced through the vents can be adjusted by acting on the quantity of air admitted separately into each compartment by means of any conventional device located before the flexible connector.

As already explained, water circulation tubes 40 are mounted clamped between the bars 29 and the sleepers 21. We will now show how these tubes 40 are mounted at their ends. At the lowest part of the hearth, on the left in the figures, the tubes 40 are bent in s downwards and thus deviate from the grid plane to each connect to a single transverse collector 3 mounted fnxed on the box 2 The manifold 3 is connected to a water supply circuit by means of flexible pipes connected to its inlet fittings 39. At the highest part of the hearth, on the right in the figures, the tubes 40 open out. straight in another single transverse manifold o mounted & rction on friction boxes 5 integral with the casing 2. Outlet fittings 45 allow the manifold 4 to be connected by flexible pipes to the general circuit of a boiler or to a circuit of use water if necessary. The friction assembly comprises a friction pad 43 mounted between the upper face of the manifold 4 and the upper branch of each friction box and a friction pad 44 mounted on an elastic device interposed between the underside of the manifold 4 and the lower branch friction force of the Belleville washers 28 of the bar fasteners and the friction pads 44 is adapted so that the bond by adhesion ensures a sufficient frictional force bars-tube-crosspiece and collector-friction head so that the vibrations and / or jolts of the hearth do not cause any sliding between the tubes and / or the bars and the box, but sufficiently weak to yield longitudinally to the stresses of thermal expansion of the tubes and! / or bars. In this way we avoid parasitic resonances, but at the same time we avoid undesirable deformations of pipes and / or bars, that is to say of their elements.
The grid elements 10 of FIG. 4 are designed for a grid without bundles of water tubes. Their construction differs from the previous ones only in the greater height of their wings 21 and in the fact that the ears 23 are cut in these wings instead of projecting downwards. Using the same assembly as above, these are the ends of the wings 21 which will bear directly on the crosspieces 15 on which they will be directly mounted with friction, which allows them to withstand expansion play, while avoiding movement movements relative to the box, which could be due to vibrations alone and / or shakes. The assembly is the same on the leftmost cross member of fig. 3.

It is advantageous that the on and off periods of the exciters 12 are controlled by a programmed or programmable digital control 50 and that this same control stops the blowing of air, if there is one, during the application of the vibrations and / or shakes in the hearth.

 It will be noted that the invention very simply solves the problem of removing particles which have fallen through the grid. It suffices that the bottom 11 of the box has the general shape of a chute and is slightly inclined downwards to the left (FIG. 1) for it to serve as a transport and evacuation collector thanks to the appropriate vibrations and / or jolts that it undergoes as a constituent part of the box. The partitions 9 must have low openings 16 allowing the passage of the particles on the bottom 11.

Claims (13)

 1. Inertia hearth for solid fuels comprising a horizontal or inclined grid (1) subjected to vibrations and / or tremors generated by a generator (12) of directed vibrations and / or tremors, with a slight oblique deviation upwards, substantially in the desired direction of progression of the solids on the grid (1) and comprising a chassis (2) for supporting the grid, characterized in that the chassis (2) is rigid and it is made up of a vibrating and / or shaking chassis , mounted resiliently, on which is directly mounted the generator (12) of vibrations and / or tremors and the grid (1) is fixed in contact with the chassis (2) at at least two points, at least one of which comprises a shock absorber with friction (28).  2. Inertial hearth according to claim 1, in which the grid (1) consists of a plurality of parallel bars (10, 20) arranged in the direction of progression of the solids, characterized in that the bars (10, 20) are each linked to the chassis (2) by at least one shock-absorbing connection means constituted by a friction fastening device (26, 28, 30) ensuring a friction force greater than the action force or inertia reaction of the bars (10, 20) to be trained or supported in vibrations and / or jolts. 3. Hearth according to claim 2, wherein the frame (2) comprises crosspieces (15) upper, characterized in that each bar (10, 20) is connected by at least one friction damper (26, 28, 30) at least two upper crosspieces (15). 4. Hearth according to claim 3, characterized in that each bar extending from one end to the other of the grid consists of several elements (10, 20) arranged contiguous end to end and of which one end, at least , is frictionally linked to the chassis (2) via the crosspieces (15). 5. Hearth according to any one of claims 3 and 4, characterized in that each bar (10, 20) has a general shape of inverted U.  6. Hearth according to any one of claims 3 to 5, characterized in that the bars (10, 20) are joined in parallel and their junction faces (36) vis-à-vis have grooves (37) constituting vents d air intake. 7. Hearth according to claim 2, characterized in that the bars (10, 20) comprise lugs (23) of attachment by which they are clamped in contact with the chassis (2) by means of connecting rods (26), constituting tie rods, and springs with large clamping force, such as stacks of Belleville washers (18).  8. Hearth according to claim 3, in which the frame (2) is made up of a partitioned box for supplying and distributing combustion air, characterized in that upper cross-members (15) are arranged at least in line with each partition (9).  9. Hearth according to claim 1, in which are arranged under or in the grid (1) bundles of tubes (40) of fluid circulation parallel to the direction of progression of the solids, and connected to at least one of the ends of the grid to a manifold (3, 4), characterized in that at least at one end of the grid (1) the manifold (4) is mounted movable and this manifold (4) and / or the connected ends of the tubes (40 ) of fluid circulation are linked to the chassis (2) by a friction damping device (5).  10. Hearth according to claims 7 and 9 combined, characterized in that the tubes (40) are interposed in clamping between the bars (15) and the frame (2). 11. Hearth according to claim 1, characterized in that it is associated with a digital control (50) programmed and / or programmable intermittent start of the generator (12) of vibrations and / or jolts. 12. Hearth according to claims 8 and 11 combined characterized in that the operating command of the vibration generator and / or shaking is associated with a concomitant command to stop blowing air through the grill and vice versa.  13. Hearth according to claim 8, characterized in that the bottom (11) of the box (2) is shaped collector of transport and evacuation. Hearth according to claim 13, characterized in that the transverse partitions (9) are open (16) in their zone adjoining the bottom (11) of the box (2).