FR2614394A1 - Incineration furnace with hearth rotating around a vertical axis - Google Patents

Abstract

This incineration furnace comprises, on the one hand, a stationary arch 7, a stationary outer wall and a central core which delimit, with the rotating hearth 2, an annular incineration chamber 11, and, on the other hand, means imparting to the hearth 2 a stepped rotational movement in order to bring each of its waste reception segments successively to a feeding zone A, with a waste reception hopper 8, to a zone B for promoting the combustion of the waste by means blowing a delivery of air through perforations in the segments of the hearth 2, to a raking zone C, where the waste in combustion is turned over, and to an ash removal zone. According to the invention, on the one hand, the arch 7 comprises, after the raking zone C, and before a gas discharge zone F, a radial projection 12 which generates turbulence promoting the combustion of the waste and of the gas, and, on the other hand, is lowered, at 7a, downstream of the removal zone, in order to constitute a zone G for calcining the waste by infrared radiation, whilst the feeder hopper 8 is arranged laterally to the incineration chamber 11 and communicates with the latter through a feeding chute 15, which constitutes a waste reserve and emerges above the lower wall 20 of a filling channel 18, which, inclined towards the hearth 2 and tangentially to the rotational trajectory of this hearth, is combined with a push member 22.

Description

 "Incineration furnace with a hearth around a vertical axis".

 To incinerate household refuse, it is known to use rotary hearth ovens. This type of oven comprises, as shown in the attached FIG. 1, a tang 2 which can rotate step by step around a vertical axis. This sole is composed of perforated segments carried by a frame and is associated with lower hoppers 3 and 3 directing the fine ashes on the ground. Those 3 direct the blowing air coming from nozzles 4 towards the perforations on which the sole segments are provided. The oven also includes a central core 5, a fixed external peripheral wall 6 and a fixed vault 7. These elements define, with the hearth, an annular incineration chamber 11.

 During its rotation, the hearth 2 passes successively to a feed zone A where it receives a metered quantity of waste at a combustion activation zone visible at B in FIG. 3, at a ringing zone C (FIG. 3 ), and finally to a zone D for the removal of unburnt residues. In general, the hot gases are evacuated by a duct with cyclone dedusting and used in an exchanger to produce steam.

 In current ovens, the feed is provided by a hopper 8 disposed above the vault 7 and the opening of which is closed by a sliding drawer 9, also closing an opening 10 formed in the vault. This feeding method has many drawbacks stemming from the arrangement of the hopper and the need to provide significant functional clearances in the drawer to allow its movement, despite its fouling with tarry residues. When the oven is opened, and during loading, the hot gases escape outside the oven by reducing the thermal efficiency of the installation by raising the temperature of the room and by carrying smoke and dust which pollute and dirty the room and the other equipment. Finally, even when the drawer is in the closed position, its functional clearances prevent the obtaining of a seal and allow the passage of gases therefore, cause pollution of the premises, and soiling of the equipment and the site.

 It therefore appears that this loading method reduces the energy efficiency of the oven, due to the poor regulation of the primary combustion air.

 One of the objects of the invention is to provide a furnace having a thermal efficiency higher than the current furnace, free from pollution by the gases escaping therefrom, and leading to a reduced operating cost.

 When such ovens are supplied with waste containing plant products with a high water content such as watermelons, melons, pumpkins, it turns out that, despite the activation of the hearth by the combustion air and the heat radiation from the walls from the oven heated white by gases, these plants do not have time to calcine to the core during their trajectory in the annular chamber and thus increase the volume of unburnt residues which must be removed.

This incineration defect also appears for compact plants and poor conductors of heat forming unburnt matter, that is to say polluting products.

 Another object of the invention is to provide an oven calcining even plants with a high water content, and making it possible to reduce the volume of unburnt residues and to increase the energy efficiency of the installation.

 According to the invention, the vault, on the one hand, comprises, after the ringing zone and before a gas exhaust zone communicating with a vertical duct and a radial projection, generating turbulence activating the combustion of waste and that of gas and is lowered, upstream of the evacuation zone and at least until the end of this zone to constitute a zone for calcining waste by infrared radiation, while the feed hopper is disposed laterally to the incineration.

and communicates with the latter by a goulotted'alimentat.ion, constituting reserve of waste and opening above the lower wall of a filling channel which, inclined towards the floor and tangential to the rotary trajectory thereof, is associated with a pusher, with intermittent operation, distributing the waste on the floor by forming a continuous belt, and that the evacuation zone comprises a rotary extractor, connected to motor means capable of passing it from a dam position in the annular chamber, in a position for evacuating the ashes from this chamber.

 The use of a feed chute forming a reserve of waste, that is to say constituting an accumulation zone, makes it possible to use this waste as means for closing the conduit. The waste thus opposes any leakage of air or gas through the conduit and any external pollution. It is the same in the inclined filling channel, a channel which is permanently filled with waste and closed off on the outside by the pusher. The cyclic movement of the latter on the lower wall of the channel ensures the pushing of a quantity of waste on the floor. The operation of the pusher synchronized or simultaneous with the rotation of the floor, is determined at the option of the operator depending lower calorific value and humidity of the waste and so as to always form on it a continuous ribbon of waste, and not juxtaposed heaps favoring the location of combustion foci between the heaps.

When the pusher moves a quantity of waste in the direction. from the end of the channel, not only does it drop this waste on the floor but causes the upturn of the waste collapse face, extending between the belt and the end of the channel, the face which, previously, was ignited by the heat radiation from the combustion chamber. As a result, the ignited waste mixes with the waste being spilled on the mat and ensures the ignition of the fire inside this mat as soon as it is formed. The fire is thus distributed in a homogeneous manner, which avoids the formation of preferential craters and ensures the ignition of the entire layer, as soon as it is formed, and increases the length of the fire and its thermal efficiency.

 The long length of the feed chute, necessary to ensure its reserve function, allows it to pass through the wall of the room and to place the hopper outside the room. Thus, the loading of the hopper by a large capacity grapple can be done outside the room, above the waste storage pit. As a result, the dust caused by the loading of the hopper evolves outside the premises and no longer constitutes a source of pollution of the latter.

 During the incineration, the baffle of the vault puts the hot gases in turbulence and promotes their penetration into the layered waste. These receive an additional calorific contribution improving their combustion and their dehydration without any additional cost.

This improvement in combustion is all the more effective since it is carried out immediately after the old-fashioned tackling, that is to say after the waste has been brewed to bring to the surface those which are larger, and therefore less affected by fire. .

 The hot gases supplied can be used immediately, which reduces the manufacturing and operating costs of the installation while increasing thermal efficiency.

 Lowering the vault before the evacuation zone brings the waste closer to the infrared emission zone and increases the efficiency of the radiation on products that have not yet been calcined because they are poor conductors or loaded with water at their core. Finally, the disposal of the means of evacuation as close as possible to the loading area makes it possible to use a rotary extractor providing the possibility of either turning part of the ashes, or extracting them completely, or letting them accumulate on this extractor to increase the duration of their parking in the oven, at the operator's choice. It follows from the above that these various provisions combine with each other to reduce pollution, operating costs and improve energy efficiency, at least compared to an existing oven with the same floor area and same chamber volume. annular.

 In one embodiment of the invention and in order to further improve the combustion of the waste, each of the tackles arranged in the tacking zone and passing through the outside wall of the furnace through openings, is constituted by a frustoconical tubular body, of prismatic section, comprising in its walls perforations constituting ventilation nozzles, is fixed, by its end of larger diameter and external to the furnace, in a sheath which, connected to a source of combustion air, is articulated around a horizontal axis on a yoke and is associated with means capable of making it penetrate, the point forward, into the waste mat, with means capable of straightening it substantially horizontally at the end of the introduction stroke and means capable of making it oscillate around its articulation on the yoke.

 Thus, by penetrating radially into the annular chamber, each nerdy sinks first on the waste mat before lifting it and then shaking it according to the fork technique used to rekindle a fire with a fork. These successive operations are carried out with an air supply inside the carpet, which has the effect of taking off the waste adhering to the floor, of facilitating their reversal and to form a new carpet composed of the fine incandescent resting on the floor and supporting larger waste which will then be more easily dehydrated and incinerated.

 This operation, making it possible to obtain a thick fire catch and aeration of the waste mat, is carried out just before the zone of the hearth where the turbulences of the hot gases increase combustion and before passing through the calcination zone of the unburnt so to promote combustion in these areas and further reduce the volume of unburnt.

 Other characteristics and advantages will emerge from the description which follows, with reference to the appended diagrammatic drawing, representing, by way of nonlimiting example, an embodiment of this rotary hearth furnace.

FIGS. 1 and 2 are views in cross section through the supply and extraction stations respectively of a traditional oven and of the oven according to the invention,
FIG. 3 is a plan view from above of the oven according to the invention,
FIG. 4 is a sectional view along IV-IV of FIG. 3 showing the cross section of the furnace in the combustion activation zone,
FIGS. 5 and 6 are sectional views along VV of FIG. 3 showing, in the coring area, a coring, respectively, in the rest position and at the end of engagement in the oven,
FIG. 7 is a sectional view along VII-VII of FIG. 3 showing the cross section of the furnace in the gas exhaust zone,
Figure 8 is a schematic view corresponding to the development of the annular chamber showing the different phases of waste incineration.

 Figure 9 is a view similar to Figure 8 showing an alternative embodiment of the oven.

 Like the traditional oven, the oven according to the invention comprises a rotary hearth 2, boxes for receiving fine ash 3 from the conduits 4 bringing the combustion air, a central core 5, an outer wall 6 and a vault 7.

 According to the invention, this oven comprises an arrangement of its vault and arrangements respectively of the loading station A, the tackling station C, the evacuation station D, and the gas exhaust zone F but also has a turbulence zone E, a waste calcination zone G. As shown diagrammatically in FIG. 8, the vault comprises, after the ringing zone C, a projection 12 promoting, in the annular incineration chamber, the formation of turbulences of hot gases. This turbulence zone E extends to the end of the gas exhaust zone F. In this zone F, the annular chamber 11 comunicates with a vertical duct 13 and is associated with nozzles 14 for injection d combustion air.

 At the end of the turbulence zones E and of exhaust F, and upstream of the extraction zone D, the arch 7 is lowered at 7a to form the calcination zone G. In the embodiment of FIG. 8, the lowering of the vault extends to the feeding zone A while in the embodiment of FIG. 9, this lowering stops at the end of the calcination zone, the feeding station then being in elevation with respect to chamber 11, and not inscribed in the height of this chamber as in FIG. 8.

 The advantages provided by these variations in height of the vault will be highlighted when describing the operation of the oven.

As shown in FIG. 2 representing the feed zone of this oven, the feed hopper 8 is disposed laterally to the incineration chamber 11 and communicates with a long chute 15, inclined relative to the vertical by a value included between
O and 300. In this embodiment, the chute 15 inclined at 300 crosses the wall 16 of the room containing the oven and constituting the wall of the pit 17 for storing waste. The hopper 8 is therefore in the pit immediately in the path of the grapple supplying it. This arrangement reduces the feeding time and the operating cost but also isolates the room from the dust that forms on each loading of the hopper.

 The lower end of the conduit 15 opens into a supply channel 18 which, like. shown in Figure 8, is delimited between the upper edge of an opening 19 formed at the base of the conduit. 15 and a wall 20, inclined and extending the arch 7a in the direction of the sole. This channel 18 is substantially tangential to the average diameter of the sole 2, as shown in FIG. 3. I1 is associated with a pusher 22 closing the opening 19, sliding on the wall 20 ~ and the part of which outside the channel is connected to means actuation, such as a jack 23 (Figures 3 and 8j, intermittent operation and whose operating mode simultaneous or synchronized with the rotation of the floor is defined by the operator.

 In operation, the grapple deposits in the hopper 8, a quantity of waste which is added to the waste accumulating in the conduit 15 and constitutes with these closure plug opposing the passage in the conduits of hot gases and combustion air.

The waste rests on the inclined wall 20 (Figure 8; and flows to the end thereof. When the pusher comes into action and displaces a quantity of waste to the lower end of the wall 20 and forces them to fall in cascade on the floor whether it is stopped or in motion. This forms a continuous carpet 24 of waste. The excess waste and that which escapes by gravity from the downstream end of the conduit 15 form a pile 25, the landslide face 25a immediately ignites under the action of hot gases at a temperature between 900 and 10000 C. During the action of the pusher 22, the waste in combustion on the face 25a fall and mix with the other waste. They thus ensure the ignition at the heart of the waste mat in its constitution. This ignition is accelerated by additional air blown in through a nozzle 21 arranged at the end of the inclined wall 20 (Figures 8 and 9).

 All of these operations are carried out in the annular chamber 11, without the hot gases being able to escape to the outside, therefore without heat losses.

 To avoid any external pollution at the end of the cycle, that is to say when the chute 15 is gradually emptied of the waste without new supply of waste by the hopper, the upper end of this chute is provided with a valve 26 which, visible Figure 2, is adapted to close the opening of the hopper 8 and to oppose the exhaust to the outside of the combustion gases.

 The sectoral rotation of the floor 2 leads the waste mat into the combustion activation zone B, where the combustion air 27 (FIG. 4) arriving in the boxes 3 passes through the orifices provided in the floor 2. At this Indeed, it should be noted that, according to the invention, each of the boxes 3 intended to recover the fine ash, is constructed in the form of a closed structure opposing the exhaust of the combustion air through any opening other than the perforations in the sole. To this end, as shown in FIG. 4, the opening 35 made in each box to allow the escape of fines 36 is closed by a flap 37 articulated around a horizontal axis 38 on the box 3. This flap is integral of a lower support leg 39 resting, by a roller 40, on a circular rail 42. As will be specified below, the rail 42 is interrupted in the evacuation zone D so that, in this zone, the flap 37 can be lowered by gravity, releasing the fines. The support legs 39 assigned to the different boxes 3 also have the advantage of improving the support of the sole 2 during the rotation of the latter. They therefore make it possible to reduce the dimensions of the structure normally used to compensate for the overhang of the sole 2. Preferably, each box 3 is provided with an internal partition 70 associated with a flap 72, articulated at 73 and in support, by its lower end, on the flap 37. When the flap 37 is in the closed position, as shown in FIG. 4, the wall 70-flap 72 assembly isolates the box 3 from the circular slot 74 formed between the outer edge of the hearth and the wall 6 of the oven and prevents the combustion air preferentially escaping through this slot and promotes the formation of lateral craters in the carpet.

 As it advances in the combustion activation zone, the thickness of the mat 25 is reduced, as shown in FIG. 8. In the nerardage zone, and in known manner, the nerds 43 are introduced into the incineration chamber passing through openings 44 formed in the outer wall 6 of the oven. According to the invention, each nerdy 43 is constituted by a frustoconical tubular body of prismatic section crossed, in each of its longitudinal walls, by orifices 45 constituting ventilation nozzles. As shown in Figures 5 and 6, each nerdy 43 is linked, by its end of larger diameter, and outside the oven, to a sheath 46 articulated around a horizontal axis 47 carried by a yoke 48.The yokes of the different sheaths 46 are fixed on a common support 49 articulated, at 50, at the upper ends of connecting rods 52, articulated by their lower ends, at 53, on a fixed bearing 54. The connecting rods are connected to motor means, not shown, such as by example a jack capable of communicating to them a pivoting bringing them from the position shown in strong lines in Figure 5, to the position shown in strong lines in Figure 6 and vice versa.

 Each of the sleeves 46 is provided with a lever 55 carrying a roller 56 capable of coming to bear against a stop 57, projecting from the wall 6 of the oven. This stop 57 is advantageously constituted by a cam, or an eccentric, wedged on a shaft 58 linked to means capable of driving it in rotation cyclically. The setting angle of each of the cams 57 on the shaft 58 is different from one cam to another.

 Thus, at each stop of the sole, the nerds, five in number in this embodiment, are introduced with the point forward in the annular chamber, are raised relative to this point, thanks to the circular movement which is communicated to them. by the connecting rods 52. During this engagement, the nerds scrape the surface of the sole 2, take off the waste adhering to it and allow the fine incandescent to fall on the sole to form a bed of embers.

Takeoff and activation of the oven are facilitated by the air arriving at the sleeves 46 and escaping through the nozzles 45 of the nerds.

 When the rollers 56 carried by the lever 55 come into contact with the cams 57, not driven in rotation, they cause by their support, and by the rocking movement of the connecting rods 52, the straightening of the tacky 43 which then take a substantially horizontal position by lifting all or part of the waste pile. At this stage, as shown in FIG. 6, the rotation of the cams 57 communicates, to the different nerds, a movement oscillating around their horizontal articulation axis 47, a movement which has the effect of disaggregating the heap of waste raised by ensuring the separation of unburnt waste from calcined waste and bringing the former to the surface of the bed of embers previously formed, to promote their subsequent dehydration and calcination.

 Thanks to their structure, these nerds modify the distribution of waste on the hearth, revive the fire, improve the setting of the fire and thickness, while ensuring ventilation of the hearth as a human being activating a waste fire. Finally, and unlike the current nerds, when the nerds according to the invention are removed from the oven, they no longer support waste and, consequently, do not risk collecting them against the external wall 6 of the oven by unbalancing the layer combustion.

 The waste belt 24 then reaches the turbulence zone E, zone in which, as shown in FIG. 8, the hot gases from the annular chamber 11, describe whirling paths 27 which are incident with respect to the belt 24. In other In other words, the hot gases which, in other areas of the oven, pitch the pile of waste, secant it in this area and increase its core temperature. The turbulence zone E is, in fact, partially common with the exhaust zone F where the nozzles 14 inject combustion air. Thus, the combustion air mixes better with the swirling hot gases. The resulting supply of oxygen makes it possible, due to the high temperature of the gases, to immediately ignite the ash particles suspended in the gases and thus ensure, in zone F and from the start of the exhaust duct 13, the complete combustion of oxidizing gases.

 The hot gases are thus subjected in the furnace to a rise in their temperature increasing the efficiency of the turbulence attacking the waste mat. As soon as they come out of the oven, they can be sent to a heat exchanger, which, by reducing their path, reduces their heat loss and increases the quantity of calories they give up and the thermal efficiency of the installation.

 The temperature inside the mat 24 is increased before it enters the calcination zone G, that is to say in the zone which, as shown in FIGS. 7, 8 and 9, has a lowering of the vault 7 of the oven. In this zone, the infrared rays 28 emitted by the burning waste and reflected by the roof 7a, have a maximum efficiency much higher than that which they have in a current section of the furnace, shown in section in FIG. 4 and. that of a current oven in FIG. 1. As a result, they have a much higher calorific power allowing them to completely incinerate plants loaded with water and which have hitherto been only calcined.

 This incineration is all the more effective as the thickness of the mat 24 is reduced and it is carried out over a long stroke. This stroke is provided by the approximation towards the supply zone A of the evacuation means. In fact, in the oven according to the invention, the ash removal means are separated from the feed zone A by an angle b (FIG. 2, of value equal to the operating pitch of the hearth, while in a traditional oven, they are separated by substantially 90, that is to say of a value equal to several steps, due to the tangential evacuation of the ashes by means of a fixed wall.

 This gain in surface area and residence time is used to ensure total incineration of the waste, therefore to further increase the thermal efficiency of the oven and reduce the volume of ash.

 As shown in Figures 2 and 3, the discharge means are constituted by a rotary flap 60 extending transversely in the annular chamber and articulated on the furnace, by a vertical shaft 62solidated from its outer edge. The end of the shaft 62, passing through the vault 7a, is secured to a lever 63 connected to actuation means, such as a jack 64 shown in FIG. 3.

The other end of the flap 60 is provided, as shown in this figure 3, with a roller 65 bearing on the sole. This flap is arranged near an evacuation duct 66 opening into a box 67 filled with water to avoid pollution of the room by the ashes, and connected to an extractor conveyor. In a variant not shown, the flap is articulated at mid-length, and forms a butterfly.

 It is easily understood that the ashes 69 brought into the evacuation zone by the movement of the hearth 2, can easily be pushed into the conduit 66 by the flap 60. This operation not only makes it possible to remove the ashes but also to release the sole to allow it to receive a new carpet of waste. The rotation of the shutter, controlled at the operator's choice, makes it possible to regulate the evacuation of the ashes according to the operation of the oven and, for example, evacuate the ashes after a period of accumulation against the shutter to further increase their stay in the oven and reduce their volume.

 As shown in FIG. 2, at the same time as the ashes are poured into the box 67 and thanks to the interruption, in this single zone, of the rail 42 serving to support the support leg 39, the flap 37, d 'shutter box 3, tilted by gravity in the open position, also releases the flap 72 and allows the fines 36 to fall into the box.

 Of course, ramps are provided downstream of this zone for, by bringing the support leg 39 in its vertical position and the roller 40 on the rail 42, ensuring the closing of the flap 37 with pivoting of the flap 72 of insulation of the box 3.

 The various characteristics of the invention which have been described above, not as a function of their importance but as and when they are used in the operation of the furnace, combine to reduce the volume of the ashes, to increase the energy efficiency of the oven, improve its operation, facilitate its maintenance, reduce its operating cost and eliminate any nuisance in the room.

Claims (12)

CLAIMS.  1. Incineration furnace with rotary hearth around a vertical axis of the type comprising, on the one hand, a fixed vault (7), a fixed external wall (6o and a central core (5) delimiting, with the rotary hearth (2i, an annular incineration chamber (11) and, on the other hand, means communicating to the hearth (2) a stepwise rotation movement to bring each of its waste reception segments, successively to a zone supply (A), with a hopper (8) for receiving the waste, to a zone (B) for activating the combustion of the waste by means (4) blowing an air flow through the perforations of the segments from the sole (2i, to an area (C) of old-fashioned tackling, returning the waste in combustion, and to an area (D) for evacuation of the ashes, characterized in that, on the one hand, the arch (7; , after the zone (C; of netting, and before a zone (F) of gas exhaust, communicating with a vertical duct (13), a radial projection (12 "generating turbulence has ctivant the combustion of waste and that of gases, and, on the other hand, is lowered, (in 7ai, upstream of the evacuation zone (D) and at least until the end of this zone, to constitute zone ( G) of calcination of waste by infrared radiation, while the feed hopper (8, is disposed laterally to the incineration chamber (11, and communicates with the latter by a feed chute (15j, constituting reserve of waste) and opening above the bottom wall (20) of a filling channel (18) which, inclined in the direction of the hearth (2) and tangential to the rotary trajectory thereof, is associated with a pusher (22) , intermittent operation, distributing the waste on the floor by forming a continuous belt, and that the discharge zone (D) comprises a rotary extractor (60), connected to motor means capable of passing it from a position of barrier in the annular chamber (11), in a position for evacuating the ashes from this chamber.  2. Oven according to claim 1 characterized in that the lowered part of the vault extends to the loading area (A).  3. Oven according to any one of claims 1 and 2 characterized in that the feed chute (15) is inclined relative to the vertical by a value between 0 and 300, and has at its lower upstream end a opening (19) through which the pusher (22) passes.  4. Oven according to claim 1 and any one of. Claims 2 to 3 characterized in that the feed chute (15) is provided at its upper end with an oscillating valve (26) for closing the opening of the hopper (8).  5. Oven according to claim 1 and any one of claims 3 to 4 characterized in that each tacky (43), disposed in the area (C) of tacking and passing through openings (44) the outer wall (6) of the oven, is constituted by a frustoconical tubular body of prismatic section, traversed in its longitudinal walls by perforations (45) constituting ventilation nozzles, is fixed, by its end of larger diameter and external to the oven, in a sheath (46 ), connected to a source of combustion air and articulated around a horizontal axis (47) on a yoke (48), and is associated with means (52) capable of making it penetrate, the point forward, into the waste, to means (56-57) capable of straightening it substantially horizontally, at the end of the introductory stroke, and to means (58) capable of making it oscillate around its axis of articulation (47 ) on the yoke (48).  6. Oven according to claim 5 characterized in that the yoke (48) of each nerdy (43) is integral with a support (49) which, common to the different nerds, is itself articulated at the end of connecting rods (52 ) able to impart a semi-circular movement of introduction into the oven and withdrawal.  7. Oven according to all of claims 5 and 6 cactérisé in that the sheath (46) of each nerdy (43) is provided with a lever (55) suitable, at the end of the movement of introduction of the nerdy (43) in the oven, to come into abutment against a stop (57) projecting from the outer wall (6) of the oven, to bring about the substantially horizontal of the tacky (43), with lifting of the waste.  8. Oven according to all of claims 5 to 7 characterized in that each of the stops (57) is constituted by a cam which, fixed on a shaft (58) connected to means capable of driving it in rotation cyclically , is wedged on this shaft (58) with an angle different from the wedging angles of the neighboring cams, associated with the other nerds.  9. Oven according to claim 1 and any one of claims 2 to 8 characterized in that the inclined wall (20) of the filling channel (lob) is provided at its lower end with a blowing nozzle (21) of air.  10. Oven according to claim 1 and any one of claims 2 to 9 characterized in that it comprises in the area (F) of exhaust. gas from the combustion air injection nozzles (14) causing complete combustion of the oxidizing gases and activation of the combustion of the waste mat.  11. Oven according to claim 1 and any one of claims 2 to 10 characterized in that the evacuation zone (D) is separated from the supply zone (A) by a value corresponding to the angular pitch of rotation of the sole.  12. Oven according to claim 1 and any one of claims 2 to 11 characterized in that each of the boxes (3), disposed under the hearth to recover the fine ash (36), is provided with a flap (37j which , articulated around a horizontal axis (38) and closing the opening (35) for evacuation formed in the bottom of the box is integral with a lower support leg (39), supported by at least one roller ( 40j on a circular rail (42), this rail (42) being interrupted, in the ash evacuation zone (D), to allow the leg (39) of the shutter (37) to tilt by gravity and the opening of the box (3) above a tank (67) for receiving unburnt products.