EP3066405B1 - Device for the hot processing of granular products and method for regulating the temperature of emanations produced by a device for the hot processing of granular products - Google Patents

Description

TECHNICAL AREA

The present invention relates to the general technical field of the hot treatment, including drying, of granular products of the aggregate, pebble or aggregate type, which are intended for example for the manufacture of bituminous products. The present invention relates in particular to devices designed to perform such treatment, and to methods of regulating the temperature of volatile emanations produced by such heat treatment devices.

• une enceinte de forme générale sensiblement cylindrique définissant un axe longitudinal, l'enceinte étant pourvue, au voisinage de l'une de ses deux extrémités, d'une entrée principale permettant l'introduction de produits granuleux à l'intérieur de l'enceinte, et étant pourvue, au voisinage de l'autre extrémité, d'une sortie permettant l'extraction des produits granuleux hors de ladite enceinte, lesdits produits granuleux étant destinés à subir un traitement en circulant à l'intérieur de ladite enceinte depuis l'entrée principale jusqu'à la sortie selon un sens de circulation,
• un moyen de chauffe qui est situé à l'intérieur de ladite enceinte, et qui est conçu pour générer un flux de séchage orienté à contre-courant du sens de circulation, et traversant une section de séchage de l'enceinte, le flux de séchage étant apte à contribuer au séchage desdits produits granuleux au sein de la section de séchage,
• un évacuateur principal d'émanations volatiles produites à l'intérieur de l'enceinte, l'évacuateur principal étant connecté à ladite enceinte par un premier embranchement, et étant conçu pour évacuer hors de l'enceinte un flux principal d'émanations,
• un évacuateur dérivé qui est connecté d'une part à ladite enceinte par un deuxième embranchement au niveau de la section de séchage, en amont du premier embranchement en considération du flux de séchage pour prélever un flux dérivé d'émanations à l'intérieur de ladite enceinte, l'évacuateur dérivé étant connecté d'autre part audit évacuateur principal pour transmettre le flux dérivé audit évacuateur principal, ledit évacuateur dérivé étant doté d'un moyen de réglage du débit du flux dérivé.

The present invention relates more particularly to a device for the hot treatment of granular products, such as pebbles or aggregates, comprising:

• an enclosure of generally substantially cylindrical shape defining a longitudinal axis, the enclosure being provided, in the vicinity of one of its two ends, with a main inlet allowing the introduction of granular products inside the enclosure, and being provided, in the vicinity of the other end, with an outlet allowing the extraction of the granular products out of said enclosure, said granular products being intended to undergo treatment by circulating inside said enclosure from the inlet main until the exit according to a direction of circulation,
• a heating means which is located inside said enclosure, and which is designed to generate a drying flow directed against the flow direction, and passing through a drying section of the enclosure, the drying flow being able to contribute to the drying of said granular products within the drying section,
• a main evacuator of volatile emanations produced inside the enclosure, the main evacuator being connected to said enclosure by a first branch, and being designed to evacuate out of the enclosure a main flow of emanations,
• a bypass evacuator which is connected on the one hand to said enclosure by a second branch at the level of the drying section, upstream of the first branch in consideration of the drying flow in order to take a flow derived from emanations inside said enclosure, the bypass evacuator being connected on the other hand to said main evacuator to transmit the bypass flow to said main evacuator, said bypass evacuator being provided with means for adjusting the flow rate of the bypass flow.

• une enceinte de forme générale sensiblement cylindrique définissant un axe longitudinal, l'enceinte étant pourvue, au voisinage de l'une de ses deux extrémités, d'une entrée principale permettant l'introduction de produits granuleux à l'intérieur de l'enceinte, et étant pourvue, au voisinage de l'autre extrémité, d'une sortie permettant l'extraction des produits granuleux hors de ladite enceinte, lesdits produits granuleux étant destinés à subir un traitement en circulant à l'intérieur de ladite enceinte depuis l'entrée principale jusqu'à la sortie selon un sens de circulation,
• un moyen de chauffe qui est situé à l'intérieur de ladite enceinte, et qui est conçu pour générer un flux de séchage orienté à contre-courant du sens de circulation, et traversant une section de séchage de l'enceinte, le flux de séchage étant apte à contribuer au séchage desdits produits granuleux au sein de la section de séchage,
• un évacuateur principal d'émanations volatiles produites à l'intérieur de l'enceinte, l'évacuateur principal étant connecté à ladite enceinte par un premier embranchement et étant conçu pour évacuer hors de l'enceinte un flux principal d'émanations,
• ledit procédé comportant une étape au cours de laquelle on prélève un flux dérivé d'émanations produites à l'intérieur de ladite enceinte au niveau de la section de séchage, en amont du premier embranchement en considération du flux de séchage, et au cours de laquelle on transmet le flux dérivé audit évacuateur principal.

The present invention also relates to a method of regulating the temperature of volatile emanations produced by a device for hot treatment of granular products, of the pebble or aggregate type, comprising:

• an enclosure of generally substantially cylindrical shape defining a longitudinal axis, the enclosure being provided, in the vicinity of one of its two ends, with a main inlet allowing the introduction of granular products inside the enclosure, and being provided, in the vicinity of the other end, with an outlet allowing the extraction of the granular products out of said enclosure, said granular products being intended to undergo treatment by circulating inside said enclosure from the inlet main until the exit according to a direction of circulation,
• a heating means which is located inside said enclosure, and which is designed to generate a drying flow directed against the flow direction, and passing through a drying section of the enclosure, the drying flow being able to contribute to the drying of said granular products within the drying section,
• a main evacuator of volatile emanations produced inside the enclosure, the main evacuator being connected to said enclosure by a first branch and being designed to evacuate out of the enclosure a main flow of emanations,
• said method comprising a step during which a flow derived from emanations produced inside said enclosure at the level of the drying section, upstream of the first branch, in consideration of the drying flow, and during which the bypass flow is transmitted to said main evacuator.

PRIOR TECHNIQUE

Devices for the hot treatment of granular products, in particular aggregates intended for the manufacture of bituminous products of the asphalt type, are known and generally consist of rotary kilns generally qualified as drying drums, and optionally coating drums. The techniques used can be so-called continuous or discontinuous techniques and operate according to a so-called “ counter-current ” technique, when the movement of the heating flow is in opposition relative to the movement of the aggregates.

A known treatment device uses a drying oven in the form of a cylindrical body of revolution defining an enclosure having at least one inlet at one of its ends and an outlet at the other end, the oven of drying being driven in rotation by any suitable means while the mass of aggregates or stones to be treated is introduced through the inlet so as to progress towards the outlet to be treated. The rotation of the enclosure thus makes it possible to circulate the aggregates which enter cold and wet by the inlet, towards the other end of the outlet, while stirring them and lifting them in the enclosure using all appropriate means.

The known treatment device also uses a heating flow produced by a burner supplying a flame in the enclosure. The flame produces a flow of hot air which propagates against the direction of circulation of the aggregates inside the enclosure, and which allows said aggregates to be dried. Fumes are then generated in the heart of the enclosure, and formed in particular by dust resulting from the aggregates, by water vapor resulting from their drying, and by gases generated by the combustion of the heating means. The fumes generally flow in the direction of the hot air flow.

It is therefore necessary to evacuate and treat these fumes, which are generally polluting. For this, it is known to provide the oven, at its inlet end, with a smoke evacuation duct, for example opening onto a bag filter making it possible to remove dust from said fumes before discharging them into the atmosphere.

When the temperature of the flue gases within the exhaust duct is lower than a dew point temperature, condensation may form such as to block the bag filter, or lead to progressive corrosion of the duct filter. evacuation.

To overcome this problem, it is known to provide the furnace with a bypass channel connected on the one hand to the heating means, and on the other hand to the discharge duct, so as to transmit the heat generated by the heating means to said exhaust duct, and thus heat the fumes within said exhaust duct.

As the bypass channel is designed to take heat from the heating medium, this can be difficult to collect, since the heating medium radiates (for example near the burner flame) at an intensity requiring the implementation of a branch channel specifically designed to resist radiation. As a corollary, the maximum heating power of the device is limited by such a design. Poorly, the bypass channel, by taking heat, is likely to also take part of the oxidizer not burnt by the burner, thus altering the quality of the combustion so as to generate polluting and / or toxic substances in the fumes. .

In addition, of course, it is advisable not to heat the exhaust fumes excessively, which would entail on the one hand a substantial waste of energy linked to an unnecessary generation of heat dispersed unnecessarily in the atmosphere, and on the other hand apart from a risk of damage to the filter. To this end, the channel derived from the known device comprises a closure means designed to limit the transfer of heat to the discharge duct. In known manner, the opening of the closure means is controlled as a function of the temperature of the fumes from the exhaust duct, in order to maintain said temperature within a tolerance interval between the dew point temperature and a critical temperature. maximum.

However, in the event that a relatively large quantity of aggregates has to be dried, it is necessary to provide intense heating which can lead, on the contrary, to an undesirable rise in the temperature of the fumes in the exhaust duct, for example of likely to damage the filter. Consequently, the quantity of aggregates that can be treated by the device is found to be limited in order to preserve the integrity of the devices located downstream of the exhaust duct, in the absence of means for cooling the fumes.

Furthermore, it may prove advantageous to add a predetermined proportion of bituminous products resulting from recycling (for example recovered during maintenance operations carried out on a roadway) to the new aggregates intended for treatment, in particular to lower the costs of production of new bituminous products. It is then necessary to provide more intense heating, such as to overheat the new aggregates so that they themselves communicate heat to the products resulting from the recycling in order to dry them. Also, the drying ability of recycled products is more variable than that of new aggregates, due to their origin. Consequently, the temperature of the outlet fumes is then liable to vary over a large amplitude depending on the nature of the products circulating in the enclosure, and may suddenly cause, in an undesirable manner, condensation, or on the contrary overheating in the enclosure. the exhaust duct.

The document FR-2 632 715 describes a dryer for an asphalt paving installation provided in particular with a gas discharge pipe connected to a cold hopper and a gas discharge bypass pipe.

The objects assigned to the invention therefore aim to remedy the various drawbacks listed above and to propose a new treatment device and a new method of regulating the temperature of the emanations from the treatment device in which the regulation is particularly easy and s 'frees from all constraints, especially design.

Another object of the invention aims to provide a new treatment device and a new method of regulating the temperature of the emanations from the treatment device making it possible to effectively regulate the temperature of the emanations, even in the case where the drying ability of the vapors. products to be processed vary widely.

Another object of the invention aims to provide a new treatment device and a new method of regulating the temperature of the emanations from the treatment device, the energy efficiency of which is particularly high.

Another object of the invention aims to provide a new treatment device and a new method for regulating the temperature of the emanations from the treatment device of simple, robust and inexpensive design.

Another object of the invention aims to provide a new treatment device and a new method of regulating the temperature of emanations from the treatment device generating emanations whose temperature is within a range making it possible to avoid deterioration of the equipment. located downstream of production.

Another object of the invention aims to provide a new treatment device and a new method for regulating the temperature of emanations from the treatment device making it possible to treat granular products with eclectic properties, whether new or recycled.

DISCLOSURE OF THE INVENTION

• une enceinte de forme générale sensiblement cylindrique définissant un axe longitudinal, l'enceinte étant pourvue, au voisinage de l'une de ses deux extrémités, d'une entrée principale permettant l'introduction de produits granuleux à l'intérieur de l'enceinte, et étant pourvue, au voisinage de l'autre extrémité, d'une sortie permettant l'extraction des produits granuleux hors de ladite enceinte, lesdits produits granuleux étant destinés à subir un traitement en circulant à l'intérieur de ladite enceinte depuis l'entrée principale jusqu'à la sortie selon un sens de circulation,
• un moyen de chauffe qui est situé à l'intérieur de ladite enceinte, et qui est conçu pour générer un flux de séchage orienté à contre-courant du sens de circulation, et traversant une section de séchage de l'enceinte, le flux de séchage étant apte à contribuer au séchage desdits produits granuleux au sein de la section de séchage,

• un évacuateur principal d'émanations volatiles produites à l'intérieur de l'enceinte, l'évacuateur principal étant connecté à ladite enceinte par un premier embranchement, et étant conçu pour évacuer hors de l'enceinte un flux principal d'émanations,
• un évacuateur dérivé qui est connecté d'une part à ladite enceinte par un deuxième embranchement au niveau de la section de séchage, en amont du premier embranchement en considération du flux de séchage pour prélever un flux dérivé d'émanations à l'intérieur de ladite enceinte, l'évacuateur dérivé étant connecté d'autre part audit évacuateur principal pour transmettre le flux dérivé audit évacuateur principal, ledit évacuateur dérivé étant doté d'un moyen de réglage du débit du flux dérivé,

le dispositif de traitement étant caractérisé en ce qu'il comprend un système de régulation de la température du flux principal conçu pour agir sur le moyen de réglage afin d'augmenter ou de réduire le débit du flux dérivé en fonction de la température du flux principal.The objects assigned to the invention are achieved using a device for hot treatment of granular products, such as pebbles or aggregates, comprising:

• an enclosure of generally substantially cylindrical shape defining a longitudinal axis, the enclosure being provided, in the vicinity of one of its two ends, with a main inlet allowing the introduction of granular products inside the enclosure, and being provided, in the vicinity of the other end, with an outlet allowing the extraction of the granular products out of said enclosure, said granular products being intended to undergo treatment by circulating inside said enclosure from the inlet main until the exit according to a direction of circulation,
• a heating means which is located inside said enclosure, and which is designed to generate a drying flow directed against the flow direction, and passing through a drying section of the enclosure, the drying flow being fit to contribute to the drying of said granular products within the drying section,

• a main evacuator of volatile emanations produced inside the enclosure, the main evacuator being connected to said enclosure by a first branch, and being designed to evacuate out of the enclosure a main flow of emanations,
• a bypass evacuator which is connected on the one hand to said enclosure by a second branch at the level of the drying section, upstream of the first branch in consideration of the drying flow in order to take a flow derived from emanations inside said enclosure, the bypass evacuator being connected on the other hand to said main evacuator to transmit the diverted flow to said main evacuator, said bypassed evacuator being provided with means for adjusting the flow rate of the bypassed flow,

the treatment device being characterized in that it comprises a system for regulating the temperature of the main flow designed to act on the adjustment means in order to increase or reduce the flow rate of the bypass flow as a function of the temperature of the main flow .

• une enceinte de forme générale sensiblement cylindrique définissant un axe longitudinal, l'enceinte étant pourvue, au voisinage de l'une de ses deux extrémités, d'une entrée principale permettant l'introduction de produits granuleux à l'intérieur de l'enceinte, et étant pourvue, au voisinage de l'autre extrémité, d'une sortie permettant l'extraction des produits granuleux hors de ladite enceinte, lesdits produits granuleux étant destinés à subir un traitement en circulant à l'intérieur de ladite enceinte depuis l'entrée principale jusqu'à la sortie selon un sens de circulation,
• un moyen de chauffe qui est situé à l'intérieur de ladite enceinte, et qui est conçu pour générer un flux de séchage orienté à contre-courant du sens de circulation, et traversant une section de séchage de l'enceinte, le flux de séchage étant apte à contribuer au séchage desdits produits granuleux au sein de la section de séchage,

• un évacuateur principal d'émanations volatiles produites à l'intérieur de l'enceinte, l'évacuateur principal étant connecté à ladite enceinte par un premier embranchement et étant conçu pour évacuer hors de l'enceinte un flux principal d'émanations,
• ledit procédé comportant une étape au cours de laquelle on prélève un flux dérivé d'émanations produites à l'intérieur de ladite enceinte au niveau de la section de séchage, en amont du premier embranchement en considération du flux de séchage, et au cours de laquelle on transmet le flux dérivé audit évacuateur principal, le procédé étant caractérisé en ce qu'il comporte une étape au cours de laquelle on augmente ou on réduit le débit du flux dérivé transmis à l'évacuateur principal en fonction de la température du flux principal.

The objects assigned to the invention are also achieved using a method for regulating the temperature of volatile emanations produced by a device for hot treatment of granular products, of the pebble or aggregate type, comprising:

• an enclosure of generally substantially cylindrical shape defining a longitudinal axis, the enclosure being provided, in the vicinity of one of its two ends, with a main inlet allowing the introduction of granular products inside the enclosure, and being provided, in the vicinity of the other end, with an outlet allowing the extraction of the granular products out of said enclosure, said granular products being intended to undergo treatment by circulating inside said enclosure from the inlet main until the exit according to a direction of circulation,
• a heating means which is located inside said enclosure, and which is designed to generate a drying flow directed against the flow direction, and passing through a drying section of the enclosure, the drying flow being fit to contribute to the drying of said granular products within the drying section,

• a main evacuator of volatile emanations produced inside the enclosure, the main evacuator being connected to said enclosure by a first branch and being designed to evacuate out of the enclosure a main flow of emanations,
• said method comprising a step during which a flow derived from emanations produced inside said enclosure at the level of the drying section, upstream of the first branch in consideration of the drying flow, is taken, and during which the bypass flow is transmitted to said main evacuator, the method being characterized in that it comprises a step during which the flow rate of the bypassed flow transmitted to the main evacuator is increased or reduced as a function of the temperature of the main flow.

BRIEF DESCRIPTION OF THE DRAWINGS

• La figure 1 illustre, selon une vue schématique en coupe longitudinale, une vue générale d'un dispositif de traitement de produits granuleux conforme à l'invention.
• La figure 2 représente, selon une vue en perspective localement en coupe, une section de séchage et une section de combustion du dispositif de la figure 1.
• La figure 3 représente, selon une vue en perspective localement en coupe, la section de séchage, la section de combustion et une section de malaxage du dispositif de la figure 1.
• La figure 4 représente, selon une vue en perspective en coupe longitudinale, la section de séchage, la section de combustion et une entrée principale du dispositif de la figure 1.
• La figure 5 représente, selon une vue schématique en coupe longitudinale, un détail de réalisation du dispositif de la figure 1, savoir un dispositif de prélèvement du dispositif de la figure 1.

Other features and advantages of the invention will appear and emerge in more detail on reading the description given below, with reference to the appended drawings, given solely by way of illustrative and non-limiting example, in which:

• The figure 1 illustrates, in a schematic view in longitudinal section, a general view of a device for processing granular products according to the invention.
• The figure 2 shows, in a perspective view locally in section, a drying section and a combustion section of the device of the figure 1 .
• The figure 3 shows, in a perspective view locally in section, the drying section, the combustion section and a mixing section of the device of the figure 1 .
• The figure 4 shows, in a perspective view in longitudinal section, the drying section, the combustion section and a main inlet of the device of the figure 1 .
• The figure 5 shows, in a schematic view in longitudinal section, an embodiment of the device of the figure 1 , namely a device for sampling the device of the figure 1 .

BEST WAY TO MAKE THE INVENTION

The figure 1 illustrates a general view of a device 1 for hot treatment of granular products, such as pebbles or aggregates, in accordance with the invention.

Within the meaning of the invention, the “ granular products ” to be treated are in the form of a plurality of solid mineral elements such as pebbles, chippings, or aggregates, which may be of variable size and shape, and which are preferably intended to enter into the composition of bituminous products of the asphalt type after, for example, a coating operation with bitumen. Thus, the granular products are preferably intended for use in the field of public works.

The treatment device 1 according to the invention is designed to impart one or more transformation (s), for example of physico-chemical type, to the granular products introduced into it, the treatment including heating allowing the partial or complete drying of said products. granular. Of course, the treatment can include additional operations, for example coating granular products with bitumen, or adding additives to said granular products.

According to the invention, and as illustrated in figures 1 to 4 , the device 1 for hot treatment of granular products comprises an enclosure 2 of generally substantially cylindrical shape defining a longitudinal axis X-X '. The enclosure 2 is thus in the form of a hollow solid of revolution forming a drum, the axis of revolution of which is formed by the longitudinal axis X-X ', said enclosure 2 comprising an outer envelope formed in particular by a side wall 18 extending from one end of the cylinder to the other, enclosing an interior space within which the granular products are intended to be processed. The enclosure 2 is, due to its shape of revolution, particularly suitable for being rotated around the longitudinal axis X-X '. Of course, the enclosure 2 according to the invention may be formed by a succession of cylindrical shapes of different diameters, or by another shape of revolution without departing from the scope of the invention.

According to the invention, the enclosure 2 is provided, in the vicinity of one of its two ends, with a main inlet 3A allowing the introduction of granular products inside the enclosure 2, and being provided, in the vicinity of the other end, an outlet 4 allowing the extraction of granular products from said enclosure 2, said granular products being intended to undergo treatment by circulating inside said enclosure 2 from the main entrance 3A up to the outlet 4 in a direction of circulation C. The granular products are intended to be inserted into the enclosure 2 through the main inlet 3A while they are preferably cold and / or wet, for example at the '' using a conveyor 18 (as shown in figure 1 ). The main entrance 3A is thus designed to admit the major part of the raw materials intended to be transformed into the enclosure. The outlet 4, located substantially opposite the enclosure 2 vis-à-vis the inlet, allows the evacuation or extraction of finished or unfinished products, and in particular granular products treated in the heart of said enclosure 2, towards the outside of said enclosure 2 (the products leaving enclosure 2 through outlet 4 can for example fall by gravity into a recovery hopper not shown). The granular products discharged through the outlet 4 are treated products, preferably heated and / or dried granular products, and / or coated, and / or mixed with additives and / or mixed with products resulting from the recycling of bituminous products ( for example recovered during maintenance operations carried out on a roadway). The granular products evacuated through the outlet 4 are liable to undergo subsequent treatments within devices arranged downstream of the treatment device 1 in order to form finished products. Preferably, the granular products circulate from one end to the other of the enclosure 2, from the main inlet 3A to the outlet 4, without leaving the interior of the enclosure 2 during the treatment. Thus, the treatment of the granular products is preferably carried out continuously inside the enclosure 2. The design of the device 1 is thus relatively simple, and the treatment particularly rapid.

Preferably, the enclosure 2 is rotated by a conventional drive means (not shown) and its longitudinal axis XX 'is inclined so that the main inlet 3A is placed at an altitude higher than the outlet 4 , for promote the progression by gravity of the granular products in the direction of circulation C. The wall 18 of the enclosure 2 may be provided, near the main inlet 3A, with intake vanes 19A forming for example a propeller of axis the longitudinal axis X-X ', and making it possible to facilitate the introduction of the granular products into the chamber 2, or to induce the direction of circulation C thereto. Likewise, the wall 18 of the enclosure 2 can be provided with extraction vanes 19B designed to direct the processed products towards the outlet 4 (which is for example located in a lower zone of the enclosure 2), and in particular to avoid the agglutination of the latter at the end of said enclosure 2.

Among the treatments which the granular products are subjected to during their passage within the enclosure 2, said granular products are intended to undergo heating such as to dry them. For this, the treatment device 1 according to the invention comprises a heating means 5 which is located inside said enclosure 2. The heating means 5 according to the invention can be in the form of any known means allowing to heat granular products, of the heating resistance type, heating by electromagnetic induction or by microwave, but is preferably in the form of a fuel burner, for example fuel oil or gas (as illustrated in figure 1 ), emitting a radiant flame and / or capable of generating heat by conduction and convection. Preferably, the flame generated in the heart of enclosure 2 contributes to defining a combustion section 6C of said enclosure 2 at which said flame is located. Preferably, the side wall 18 of the enclosure 2 is protected from the heating means at the level of the combustion section 6C by suitable protective plates 20. Within the combustion section 6C, the granular products may optionally be caused to circulate between the protection plates 20 and the side wall 18 to be protected from the heating means 5.

As depicted in figure 1 , the heating means 5 formed by the burner is designed to generate heat in an oriented manner, for example by creating a current of hot air or gas channeled through the side wall 18 of said enclosure 2. According to the invention, the heating means 5 is designed to generate a drying flow F oriented against the flow direction C, and passing through a drying section 6B of the enclosure 2, the drying flow F being capable of (at least) contribute to, if not ensure totally drying said granular products within the drying section 6B. The treatment device 1 according to the invention thus has a so-called “ counter-current ” operation, the drying flow F being oriented in opposition to the direction of circulation C of the granular products in order to force all or part of the humidity of said products. granular to vaporize under the effect of dry heat, and to entrain this moisture in gaseous form with said drying stream F, to help form a main stream P of volatile emanations (described in more detail below) . The drying flow F is thus directed from the outlet 4 to the main inlet 3A, and is preferably emitted from the vicinity of the outlet end 4 of the enclosure 2, or in a middle part of the enclosure located between outlet 4 and main inlet 3A, according to the different treatments to be applied to granular products.

The drying stream F according to the invention passes through the drying section 6B, within which it is particularly suitable for drying granular products, for example by being neither too hot nor too cold. The drying section 6B is the main seat of the drying of the granular products in the heart of the enclosure, in particular insofar as the radiations produced by the heating means 5 are preferably less intense than in the combustion section 6C, so that granular products are less likely to be burnt by radiation or by the flame itself.

Preferably, the enclosure 2 successively comprises the drying section 6B, the combustion section 6C, and a mixing section 6A (as shown in figures 1 to 4 ) in consideration of the direction of flow C, the mixing section 6A being arranged downstream of the heating means 5 and making it possible to ensure the mixing and mixing of the granular products before they leave the enclosure 2 via the outlet 4. The mixing section 6A is preferably provided for mixing and mixing the granular products (new and / or from recycling) with bitumen, in order to form coated products such as asphalt. The mixing section 6A can also be provided, preferably, to mix the new granular products with granular products resulting from recycling, which have for example been introduced into said chamber 2 by an auxiliary inlet 3B (which is described below ) of said enclosure 2.

Preferably, the enclosure 2 is provided at the level of the drying section 6B with lifting means 16 for the granular products circulating in said enclosure 2, the lifting means 16 being designed to lift and release said granular products during their circulation in said chamber 2 in order to form a curtain of granular products through which the drying flow F is intended to pass. The lifting means 16 thus make it possible, thanks to the rotation of the enclosure 2, to create a mist of granular products covering all or part of the internal cross section of said enclosure 2, the granular products swirling up and down (or in any directions) of the side wall 18 in order to be aerated and dried individually, such a movement of the granular products promoting in particular the chemical and thermal exchanges between the drying flow F and said granular products in order to allow optimum drying of said granular products by absorbing heat from said drying stream F.

In addition, and particularly advantageously, the lifting means 16 of the drying section 6B preferably form a means for cooling the drying flow F, which reaches the end of the enclosure 2 near the main entrance. 3A with a temperature lower than the temperature of said drying stream F before it has passed said drying section 6B.

Preferably, said enclosure 2 is rotatable about its longitudinal axis X-X ', the lifting means 16 comprising at least two rows 11 of contiguous lifting buckets, said buckets being distributed for each row 11 over at least the majority of the circumference of said enclosure 2, and being designed to lift the granular products circulating in said enclosure 2 during the rotation thereof, in order to form at least one curtain of granular products covering all or part of the internal cross section of the 'enclosure 2.

The buckets form shovels (or trays) oriented so as, during the rotation of the enclosure 2, to fill with granular products (when the rotation brings the buckets to the lower zone of the treatment device 1), then lift the said granular products (when the rotation raises the buckets to an altitude close to the longitudinal axis X-X '), and finally pour the said granular products (when the rotation brings the buckets to the upper zone of the treatment device 1, the buckets then being overturned). Preferably, the buckets are double-volume lifting buckets, comprising two nested bins one inside the other (as illustrated in particular on figure 4 ) allowing the formation of a dense granular product curtain. Each row 11 of the bucket is formed by an annular arrangement of a plurality of buckets attached to the side wall 18.

Preferably, the enclosure 2 comprises at least one annular dam 12 (as illustrated in figures 1 and 4 ) separating the rows 11 of buckets interposed between two rows 11 of contiguous buckets, said at least one annular dam 12 being designed to limit the circulation of granular products from one row 11 of buckets to the other.

Said at least one annular dike 12 is preferably formed by an annular flat wall perpendicular to the longitudinal axis X-X ', and arranged concentrically with the enclosure 2 inside the latter, said at least one dike annular 12 being attached to the side wall 18 by a first edge, the second edge rising in the direction of the longitudinal axis XX 'to a height substantially equal to that of the buckets projecting from said side wall 18 (as illustrated in the figure 4 ). The annular dam 12 interposes the passage of granular products from one row 11 to the other, forcing them to approach the axis XX 'in order to be able to circulate in the direction of circulation C. Thanks to such a provision, the granular products are retained in the drying section 6B for a long time, regardless of the throughput of said granular products, and in particular when the throughput of said granular products is low.

Of course, the drying section 6B may include lifting devices 16 different from those mentioned without departing from the scope of the invention, since they make it possible to form a curtain of granular products capable of cooling the drying flow F.

Furthermore, according to the invention, the device 1 for hot treatment of granular products comprises a main evacuator 7A of volatile emanations produced inside the enclosure 2, the main evacuator 7A being connected to said enclosure 2 by a first branch 8A, and being designed to evacuate from the enclosure 2 a main flow P of emanations.

The treatment of granular products in enclosure 2 is likely to generate volatile emanations at the heart thereof which are entrained by the drying flow F. These volatile emanations are in the form of a fluid with gaseous behavior being released. the transformation of granular products, in particular their drying, and carrying with it particles (for example dust from granular products) and / or water in gaseous form resulting from the drying. The products of the combustion of the heating means (such as, for example, carbon compounds of the carbon dioxide or monoxide type, or else nitrogen oxides of the “ NOx” type ) also contribute to the formation of volatile fumes. The volatile fumes are in the form of charged fumes comprising both water in the form of vapor, the products of the combustion of the heating means 5, and dust in suspension resulting from the drying of the granular products. Other constituents linked to other treatments carried out in enclosure 2 can also contribute to forming the volatile fumes. Of course, these volatile fumes are liable to be polluting, and / or to smother the combustion in a manner detrimental to the operation of the heating means 5 (which requires, for example, a fresh oxidizer of the oxygen type to operate) and require be evacuated, and / or decontaminated.

Thus, the main evacuator 7A is designed to receive, evacuate, and possibly clean up all or part of the fumes carried by the drying stream F. For this, the main evacuator preferably has the form of an evacuation duct, connected in its lateral part directly to the enclosure 2 by an access opening forming the first branch 8A (as shown in figure 1 ). The first branch 8A, within the meaning of the invention forms a link between the interior space of the enclosure 2 and the interior space of the main evacuator 7A, in order to communicate (in a controlled or uncontrolled manner, and / or filtered or not) these two interior spaces to allow the circulation of emanations from one to the other of said interior spaces. Preferably, the first branch 8A is designed so that the granular products can substantially not enter the main evacuator 7A (the passage being prohibited for granular products, for example by means of a grid or a path. baffle) the intake vanes 19A can for example also contribute to such a technical effect. Thus, the main evacuator 7A is designed to substantially admit only the volatile emanations forming the main flow P (preferably transporting dust in suspension), and not to admit granular products within it.

Preferably, the first branch 8A is connected to said enclosure 2 at the level of, or upstream of, the main entrance 3A in consideration of the direction of circulation C of the granular products, for example at the end of the enclosure 2, so that the drying stream F is able to drain the volatile fumes over the entire length of the enclosure 2 in order to escape through the first branch 8A via the main evacuator 7A. Preferably, the first branch 8A is connected downstream of the drying section 6B in consideration of the drying flow F. The figure 1 shows in this regard a treatment device 1 according to the invention, the main evacuator 7A of which is connected via the first branch 8A at the end of the enclosure, parallel to the main inlet 3A. Of course, the main evacuator 7A can be connected to the enclosure 2 at a different location, since it allows the main flow P of emanations to be evacuated from the enclosure 2.

As soon as the drying stream F, carrying emanations, leaves the enclosure 2 by crossing the first branch 8A, it becomes, within the meaning of the invention, the main stream P of emanations, no longer used for drying, but being simply intended to be evacuated, and / or decontaminated.

To clean up the main stream P, the main evacuator 7A preferably comprises a filtering device, for example of the bag filter type, through which the main stream P is intended to be filtered in order to be rid of all or part of its particles. polluting. Other depolluting treatments may be implemented within the main evacuator 7A or downstream thereof, for example before rejection of the main stream P into the atmosphere, or storage of the filtered fumes.

The treatment device 1 according to the invention also comprises a bypass evacuator 7B which is connected on the one hand to said chamber 2 by a second branch 8B upstream of the first branch 8A in consideration of the drying flow F, to take a bypass flow D of emanations inside said enclosure 2, the bypass evacuator 7B being connected on the other hand to said main evacuator 7A to transmit the bypass flow D to said main evacuator 7A.

The first branch 8A is distinct from the second branch 8B. The bypass evacuator 7B is thus designed to divert part of the emanations circulating inside the enclosure 2 from a location different from the enclosure 2 from that where the first branch 8A is positioned (preferably at a place where the emanations are hotter than the emanations passing through the first branch 8A), preferably from the side wall 18 to which the second branch 8B connects said branch evacuator 7B. The derivative evacuator 7B thus subtracts a certain amount of the emanations carried by the drying stream F in order to form within said derivative evacuator 7B the derivative stream D of emanations. Advantageously, the temperature of the emanations of the derivative stream D taken upstream of the first branch 8A in consideration of the drying stream F are at a temperature different from those taken at the level of the first branch 8A.

Preferably, all of the emanations are extracted from inside the enclosure 2 by the action, or the simple presence, of the main evacuator 7A and the derivative evacuator 7B.

The branch evacuator 7B is connected to the main spillway 7A, for example at the level of a third branch 8C (as shown figure 1 ), which allows the derivative flow D to circulate from the interior of the enclosure 2 at the level of the second branch to the interior of the main evacuator 7A, within which the emanations of said derivative flow D are placed in contact and / or mixed with those of the main flow P. Alternatively, the derivative flow D of emanations and the main flow P can simply be subjected to a heat exchange in order to exchange their heat without contact, for example within a heat exchanger (not shown) of the main evacuator 7A.

Preferably, said branch evacuator 7B comprises a pipe 9 connected on the one hand to said enclosure 2 by the second branch 8B and on the other hand to said main evacuator 7A in order to connect said enclosure 2 to said main evacuator 7A (as shown at the figure 1 ). Preferably, the pipeline extends from the first branch 8B, placed at the top of the enclosure 2, and forms an elbow.

Like the first branch 8A, the second branch 8B forms a link between the interior space of the enclosure 2 and the interior space of the branch spillway 7B, in order to communicate (in a controlled manner or not, and / or filtered or not) these two interior spaces to allow the circulation of emanations from one to the other of said interior spaces. Preferably, the second branch 8B is designed so that the granular products cannot substantially enter the bypass evacuator 7B (the passage being prohibited for granular products, for example by means of a grid or a path. in baffle) a device for sampling the derivative flow D preferably contributing to produce such a technical effect. Thus, the main evacuator 7A is designed to admit substantially only the volatile fumes forming the derivative flow D (preferably containing the dust in suspension), and not to admit granular products within it.

• au moins une ouverture de prélèvement 13 du flux dérivé D ménagée à la périphérie de ladite enceinte 2, à travers la paroi latérale 18, au niveau du deuxième embranchement 8B, l'ouverture de prélèvement 13 formant par exemple un chemin suffisamment tortueux pour que les émanations puissent s'engouffrer à travers elle tout en prévenant sensiblement l'intrusion de produits granuleux,
• une jupe annulaire 14 s'étendant entre un bord intérieur 14A et une portion libre 14B, la jupe annulaire 14 étant rattachée par le bord intérieur 14A à l'intérieur de ladite enceinte 2 en amont de ladite au moins une ouverture de prélèvement 13 en considération du sens de circulation C des produits granuleux, la portion libre 14B recouvrant à distance au moins la majorité de ladite au moins une ouverture de prélèvement 13, de manière à former un paravent ou un bouclier dérivant les produits granuleux à l'écart de ladite au moins une ouverture de prélèvement, tout en incitant au contraire les émanations (charriées par le flux de séchage F) à s'engouffrer sous ladite jupe annulaire 14 afin de pénétrer dans les ouvertures de prélèvement 13,
• au moins une aube de barrage 15 rattachée à l'intérieur de ladite enceinte 2, disposée en hélice par rapport à l'axe longitudinal X-X', et disposée en aval de ladite au moins une ouverture de prélèvement 13 en considération du sens de circulation C des produits granuleux, la disposition et la forme de ladite au moins une aube de barrage 15 permettant de repousser des produits granuleux qui seraient susceptible de circuler incidemment en sens inverse du sens de circulation C, la disposition et la forme de ladite au moins une aube de barrage 15 autorisant toutefois le passage des émanations sous la jupe annulaire 14.

Preferably, the processing device 1 comprises a device for sampling the derivative flow D (as shown schematically on figure 5 , and represented at figures 2 to 4 ) comprising:

• at least one sampling opening 13 of the bypass flow D formed at the periphery of said enclosure 2, through the side wall 18, at the level of the second branch 8B, the sampling opening 13 forming for example a sufficiently tortuous path so that the fumes can rush through it while significantly preventing the intrusion of granular products,
• an annular skirt 14 extending between an inner edge 14A and a free portion 14B, the annular skirt 14 being attached by the inner edge 14A inside said enclosure 2 upstream of said at least one sampling opening 13 in consideration of the direction of circulation C of the granular products, the free portion 14B covering at a distance at least the majority of said at least one sampling opening 13, so as to form a screen or a shield diverting the granular products away from said au less an opening for sampling, while on the contrary encouraging the emanations (carried by the flow of drying F) to be engulfed under said annular skirt 14 in order to penetrate into the sampling openings 13,
• at least one barrier blade 15 attached to the interior of said enclosure 2, disposed in a helix with respect to the longitudinal axis X-X ', and disposed downstream of said at least one sampling opening 13 in consideration of the direction of circulation C of granular products, the arrangement and shape of said at least one barrier blade 15 making it possible to repel granular products which would be liable to flow incidentally in the opposite direction to the direction of circulation C, the arrangement and shape of said at least a barrier blade 15, however, allowing the passage of the fumes under the annular skirt 14.

The shape and arrangement of the annular skirt 14 make it possible, by taking advantage of the direction of circulation C of the granular products opposed to the drying flow F carrying the fumes, to create an annular opening oriented in a favorable manner for the penetration of a portion of the emanations under said annular skirt 14 while this annular opening remains inaccessible to any granular product circulating in the direction of circulation C. The annular skirt 14 thus houses said at least one sampling opening 13 for granular products.

Preferably, and as shown in the figures, the annular skirt 14 is provided on its free portion with a row 11 of lifting vanes.

Preferably, the sampling device comprises a plurality of barrier vanes 15 and a plurality of sampling openings 13 connected to an annular collector 21 (shown diagrammatically on figure 1 ) non-rotating encircling enclosure 2 and leading the fumes taken by the various sampling openings 13 to the second branch 8B then to the bypass evacuator 7B.

Preferably, the lifting means 16 are designed to form a curtain of granular products at the level of the drying section 6B, the curtain of granular products being able to absorb a quantity of heat from the drying stream F sufficient for the temperature of the main flow P is kept below a critical temperature. The critical temperature can be defined for example by the temperature above which the main evacuator 3A is deteriorated, or its impaired operation. Thus, the drying section 6B provided with the lifting means 16 forms a means for cooling the main stream P of emanations, while the bypass stream D forms a means for heating the main stream P of emanations.

According to an important characteristic of the invention, the bypass evacuator 7B is connected to the enclosure 2 by the second branch 8B at the level of the drying section 6B. Thus the bypass evacuator 7B can take a bypass flow D of emanations formed by emanations coming from the drying section 6B of said chamber 2.

Thus, advantageously, the fumes forming the bypass stream D taken from the drying section are hotter than those taken by the main evacuator 7A to form the main stream P downstream of the second branch 8B, in consideration of the drying stream F. The fumes forming the bypass flow D thus serve as a heat transfer fluid intended to be mixed with the main flow P in order to heat the latter.

Thus, the bypass evacuator 7B is connected to said enclosure 2 by the second branch 8B away from the combustion section 6B, within which the radiation and / or the heat produced by the heating means 5 would be susceptible to 'alter or damage the second branch 8B and / or the branch spillway 7B. In addition, the bypass evacuator 7B is connected to said enclosure 2 by the second branch 8B away from the combustion section 6B to substantially avoid evacuating, with the fumes, a certain proportion of unconsumed oxidizer necessary for operation. of the heating means 5, the oxidizer being for example formed by fresh air containing dioxygen, admitted into the heating means 5 upstream of said heating means 5 in consideration of the drying flow F, the oxidizer content of l the air inside said chamber 2 at the level of the drying section 6B being much lower than the oxidizer content of the air inside said chamber 2 at the level of the combustion section 6C and mixing 6A.

The bypass evacuator 7B connected to the enclosure 2 at the level of the drying section 6B thus makes it possible to take a relatively large quantity of emanations, which are relatively dense, compared for example to the quantity of unpolluted air or of oxidizer incidentally taken. Advantageously, a small amount of air not polluted will be wasted by evacuation in the main evacuator 7A, which allows the by-pass flow D to additionally constitute a high-performance coolant.

Preferably, the processing device 1 comprises an auxiliary input 3B for granular products separate from the main input 3A and connected to said enclosure 2 between the main input 3A and the output 4, as shown in figures 1 to 4 . The auxiliary inlet 3B is preferably provided with a hopper 22 located on the top of the enclosure 2 and allowing the insertion of granular products into the heart of said enclosure 2. At the level of the auxiliary inlet 3B, auxiliary vanes inlet 23 arranged inside the enclosure 2 in a helix on the side wall 18 in consideration of the longitudinal axis XX 'preferably allow a setting in motion in the direction of circulation C substantially immediately granular products introduced through the auxiliary inlet 3B, said granular products thus introduced then mixing with the granular products already present in the chamber 2 and having passed for example the drying section 6B.

The auxiliary inlet 3B advantageously allows the introduction of granular products of a different nature from those introduced by the main inlet 3A, and intended to undergo a different treatment (for example not including any passage at the level of the drying section 6B) at the heart of the enclosure 2.

Preferably, the auxiliary input 3B is connected to said enclosure 2 between the second branch 8B and the heating means 5. Such an arrangement ensures that the bypass stream D remains hot, by not being cooled by the granular products ( generally cold and humid) introduced by auxiliary input 3B.

Preferably, the auxiliary inlet 3B is designed and adapted to allow the introduction of granular products resulting from the recycling of bituminous product (and / or addition elements for the treatment), which are of size and / or composition and / or of more variable particle size than in the case of new granular products (of the type of those which can be introduced for example through the main inlet 3A), and are likely to contain a variable proportion of foreign elements such as bitumen or other unwanted elements. Granular products from recycling are for example recovered during maintenance operations carried out on a roadway.

Advantageously, the granular products introduced into the enclosure 2 via the auxiliary inlet 3B circulate in the enclosure 2 from said auxiliary inlet 3B to the outlet 4, according to the direction of circulation C, preferably without exit from inside the enclosure 2. The treatment of the granular products introduced through the auxiliary inlet 3B is thus advantageously carried out continuously inside the enclosure 2.

Preferably, the bypass evacuator 7B is provided with a means 10 for adjusting the flow rate of the bypass flow D, formed for example by a valve 10 (as shown in figure 1 ) designed to move between an open or closed position in order to block or not said bypass evacuator 7B, and in particular to block or not the pipe 9 of said bypass evacuator 7B, in order to interrupt, interfere or selectively allow the passage of the emanations of said derivative flow D. The valve 10 may be placed for example at the level of the third branch 8C, as shown in the figures. The adjustment means 10 may also include a second valve (not shown), preferably placed within the bypass evacuator 7B, for example at the level of the second branch 8B, in order to better control the flow rate of the bypass flow D. Of course. , any other means making it possible to authorize, prohibit, or adjust the flow rate of the admission of the bypass flow D into the bypass evacuator 7B may be implemented without departing from the scope of the invention, such as a valve, or a butterfly valve, or a combination of these elements, placed at the level of the first, second, and / or third branch 8A, 8B, 8C, and / or within the main spillway 7A and / or derivative 7B, so as to control the flow rate of the main flow P and / or of the derivative flow D.

Preferably, the treatment device 1 comprises a system for regulating the temperature of the main stream P designed to act on the adjustment means 10 in order to increase or reduce the flow rate of the bypass stream D as a function of the temperature of the main stream. P. The admission of a more or less important flow of derivative flow D into the main evacuator 7A allows, thanks to the mixing of said derivative flow D with the main flow P within said main evacuator 7A, to vary the temperature of the flux main stream 7A, said main stream 7A and derivative 7B being of different temperatures, the derivative stream 7B preferably being hotter than the main stream 7A. The temperature regulation system may include one or more temperature sensors of the main flow P and of the derivative flow D, as well as a device for slaving the adjustment means 10 as a function of the temperatures detected.

Preferably, the regulation system is designed to increase the flow rate of the derived flow D when the temperature of said main flow P is lower than a set temperature, and to reduce the flow rate of the derived flow D when the temperature of said main flow P is greater than the set temperature.

Preferably, the heating means formed by the derivative flow D is thus adjustable, while the cooling means formed by the drying section 6B provided with the lifting means 6B for forming the curtain of granular products is permanently active. The activation of the bypass flow D can thus allow for example the main flow P to be heated in order to be maintained at a temperature above the dew point temperature, thus avoiding the formation of condensation in the main evacuator 7A, and possibly downstream of the latter. The weakening of the bypass flow rate D, on the contrary, allows the main flow P to cool by itself thanks to the cooling means, which can make it possible for example to prevent the deterioration of pollution control installations located downstream of the main evacuator 7A.

In particular, the main stream P is liable to undergo strong temperature variations during the introduction for example of granular products resulting from the recycling of bituminous products, insofar as their receptivity to drying by their drying stream F is liable to be very variable. In addition, to treat both the granular products introduced through the main inlet 3A and the auxiliary inlet 3B, it may prove necessary to increase the quantity of heat produced by the heating means 5, which may have as a consequence of varying the temperature of the main flow P. In any situation, and whatever the quantity or the quality of the granular products admitted into the chamber 2, by any inlet (3A, 3B) thereof, the temperature of the main stream P is thus kept constant, or slightly variable, within a tolerance interval, in which the main stream P is sufficiently hot for, for example, not to generate condensation, and is cold enough not to damage or alter the main evacuator 7A.

Thus it is possible to maintain the temperature of the main stream P within this range, which is preferably between 50 ° C and 170 ° C, even more preferably between 70 ° C and 150 ° C, more preferably between 80 ° C and 130 ° C.

• une enceinte 2 de forme générale sensiblement cylindrique définissant un axe longitudinal X-X', l'enceinte 2 étant pourvue, au voisinage de l'une de ses deux extrémités, d'une entrée principale 3A permettant l'introduction de produits granuleux à l'intérieur de l'enceinte 2, et étant pourvue, au voisinage de l'autre extrémité, d'une sortie 4 permettant l'extraction des produits granuleux hors de ladite enceinte 2, lesdits produits granuleux étant destinés à subir un traitement en circulant à l'intérieur de ladite enceinte 2 depuis l'entrée principale 3A jusqu'à la sortie 4 selon un sens de circulation C,
• un moyen de chauffe 5 qui est situé à l'intérieur de ladite enceinte 2, et qui est conçu pour générer un flux de séchage F orienté à contre-courant du sens de circulation C, et traversant une section de séchage 6B de l'enceinte 2, le flux de séchage F étant apte à contribuer au séchage desdits produits granuleux au sein de la section de séchage 6B,
• un évacuateur principal 7A d'émanations volatiles produites à l'intérieur de l'enceinte 2, l'évacuateur principal 7A étant connecté à ladite enceinte 2 par un premier embranchement 8A, et étant conçu pour évacuer hors de l'enceinte 2 un flux principal P d'émanations.

ledit procédé comportant une étape au cours de laquelle on prélève un flux dérivé D d'émanations produites à l'intérieur de ladite enceinte 2 en amont du premier embranchement 8A en considération du flux de séchage F, et au cours de laquelle on transmet le flux dérivé D audit évacuateur principal 7A, et étant caractérisé en ce qu'on prélève le flux dérivé D au niveau de la section de séchage 6B.The invention also relates to a process for regulating the temperature of volatile emanations produced by a device 1 for hot treatment of granular products, of the pebble or aggregate type, comprising:

• an enclosure 2 of generally substantially cylindrical shape defining a longitudinal axis X-X ', the enclosure 2 being provided, in the vicinity of one of its two ends, with a main inlet 3A allowing the introduction of granular products to the 'inside the enclosure 2, and being provided, near the other end, with an outlet 4 allowing the extraction of granular products out of said enclosure 2, said granular products being intended to undergo treatment by circulating at inside said enclosure 2 from the main entrance 3A to the exit 4 in a direction of circulation C,
• a heating means 5 which is located inside said enclosure 2, and which is designed to generate a drying flow F directed against the flow direction C, and passing through a drying section 6B of the enclosure 2, the drying flow F being able to contribute to the drying of said granular products within the drying section 6B,
• a main evacuator 7A of volatile emanations produced inside the enclosure 2, the main evacuator 7A being connected to said enclosure 2 by a first branch 8A, and being designed to evacuate out of the enclosure 2 a main flow P of emanations.

said method comprising a step during which a derivative flow D of emanations produced inside said enclosure 2 is taken upstream of the first branch 8A in consideration of the drying flow F, and during which the flow is transmitted derivative D from said main evacuator 7A, and being characterized in that the derivative stream D is taken at the level of the drying section 6B.

The derivative stream D is taken at a level distinct from the main stream P, so that said derivative D and main stream P have a different temperature.

Thus, to help regulate the temperature of the main stream P of emanations within the main evacuator, a portion of the emanations circulating in the chamber 2 (preferably carried by the drying stream F) is cut off at the level of the drying section 6B, in order to form the derivative stream D of emanations, to then bring into contact and / or mix the derivative stream D with the main stream P. Instead of mixing the main stream P and derivative D, one can consider, without departing from the scope of the invention, subjecting them to a simple heat exchange, without necessarily being put in contact, for example within a heat exchanger (not shown) of the main evacuator 7A . The main flow P and derivative D are advantageously at a different temperature from one another, insofar as they are taken from a different location in the enclosure 2.

Preferably, the process for regulating the temperature of volatile emanations is implemented using the treatment device 1 described above and illustrated in the figures. Therefore, the bypass is preferably carried out using a bypass evacuator 7B as described above.

Preferably, the regulation method comprises a step during which the flow rate of the bypass flow D transmitted to the main spillway 7A is increased or reduced as a function of the temperature of the main flow P, the contribution of the bypass flow D to the flow main P making it possible to vary the temperature of said main flow P when the latter absorbs said bypass flow, or at least absorbs its heat, within the main evacuator 7A. By controlling the flow rate of the bypass flow D, it is thus possible to control the temperature of the main flow.

Preferably, the flow rate of the branched flow D transmitted to the main evacuator 7A is increased when the temperature of said main flow P is lower than a set temperature, and the flow rate of the branched flow D transmitted to the main evacuator 7A is reduced when the temperature of said main stream P is higher than the set temperature. The derivative flow D containing emanations whose temperature is advantageously higher than that of the emanations of the flow main flow P, we can thus use the bypass flow D to heat the main flow P. The reduction in, or the absence of, flow rate of the bypass flow D transmitted to the main evacuator 7A allows the main flow P not to be heated , so that it is able to cool down.

In fact, when it is not reheated using the derivative flow D, the emanations from the main flow P are relatively cold, because the drying flow F intended to form said main flow P on its arrival in the main evacuator P is preferably passed through the drying section 6B, provided with means for cooling said drying stream F, such as lifting means 16, the cooling means being such as to sufficiently cool said drying stream F so that said main flow P never reaches a critical temperature (regardless of the nature or quantity of granular products introduced into chamber 2), such as, for example, to deteriorate or alter the main evacuator 3A or any equipment downstream of the latter.

Preferably, the regulation method comprises a step during which granular products resulting from the recycling of bituminous products are introduced into said chamber 2 between the main inlet 3A and the outlet 4, preferably an auxiliary inlet 3B. Thanks to the design of the treatment device 1 described above, it is advantageously possible to introduce granular products whose thermal receptivity is very variable, without the risk of excessive variations in the temperature of the main stream P of emanations.

Preferably, the granular products resulting from the recycling of bituminous products are introduced into the chamber 2 between the level at which the derivative stream D is taken and said heating means 5. Introduce the granular products resulting from the recycling of bituminous products into the 'enclosure 2 at such a level ensures that the bypass stream D remains hot, by not being cooled by said granular products (generally cold and wet) introduced through the auxiliary inlet 3B.

Of course, it is also possible to introduce other elements, together or alternatively with the granular products resulting from recycling, such as additives for the treatment (for example a coating product such as bitumen) by the auxiliary input 3B, or elsewhere in the enclosure 2.

POSSIBILITY OF INDUSTRIAL APPLICATION

The invention finds its industrial application in the design, production and implementation of hot treatments of granular products, such as pebbles or aggregates.

Claims (14)

1. Device (1) for the hot treatment of granular products, of the gravel or aggregate type, comprising:

   - an enclosure (2) that is substantially cylindrical in shape overall, defining a longitudinal axis (X-X'), the enclosure (2) being provided, in the vicinity of one of the two ends thereof, with a main inlet (3A) for introducing granular products inside the enclosure (2), and being provided, in the vicinity of the other end, with an outlet (4) for extracting the granular products out of said enclosure (2), said granular products being intended to undergo treatment while travelling inside said enclosure (2) from the main inlet (3A) as far as the outlet (4) in a travel direction (C),

   - a heating means (5) that is situated inside said enclosure (2) and is designed to generate a drying flow (F) oriented in the opposite direction to the direction of travel (C), and passing through a drying section (6B) of the enclosure (2), the drying flow (F) being able to contribute to the drying of said granular products in the drying section (6B),

   - a main discharger (7A) of volatile emanations produced inside the enclosure (2), the main discharger (7A) being connected to said enclosure (2) by a first branch (8A), and being designed to discharge out of the enclosure (2) a main flow (P) of emanations,

   - a diverted discharger (7B) that is connected on the one hand to said enclosure (2) by a second branch (8B) at the drying section (6B), upstream of the first branch (8A) in terms of the drying flow (F) in order to take off a diverted flow (D) of emanations inside said enclosure (2), the diverted discharger (7B) being moreover connected to said main discharger (7A) in order to transmit the diverted flow (D) to said main discharger (7A), said diverted discharger (7B) being provided with a means for adjusting (10) the flow rate of the diverted flow (D),

   the treatment device (1) being characterised in that it comprises a system for regulating the temperature of the main flow (P) designed to act on the means for adjusting (10) in order to increase or reduce the flow rate of the diverted flow (D) according to the temperature of the main flow (P).
2. Treatment device (1) according to claim 1, characterised in that it comprises an ancillary inlet (3B) for granular products distinct from the main inlet (3A) and connected to said enclosure (2) between the main inlet (3A) and the outlet (4).
3. Treatment device (1) according to claim 2, characterised in that the ancillary inlet (3B) is connected to said enclosure (2) between said second branch (8B) and said heating means (5).
4. Treatment device (1) according to any one of the preceding claims, characterised in that said diverted discharger (7B) comprises a duct (9) connected firstly to said enclosure (2) by the second branch (8B) and secondly to said main discharger (7A) in order to connect said enclosure (2) to said main discharger (7A).
5. Treatment device (1) according to the preceding claim, characterised in that the regulation system is designed to increase the flow rate of the diverted flow (D) when the temperature of said main flow (P) is lower than a set temperature, and to reduce the flow rate of the diverted flow (D) when the temperature of said main flow (P) is higher than the set temperature.
6. Treatment device (1) according to any one of the preceding claims, characterised in that said enclosure (2) is provided, at the drying section (6B), with means for lifting (16) the granular products travelling in said enclosure (2), the means for lifting (16) being designed to raise and release said granular products in the course of the travel thereof in said enclosure (2) in order to form a curtain of granular products able to absorb a quantity of heat from the drying flow (F) sufficient for the temperature of the main flow (P) to be maintained below a critical temperature.
7. Treatment device (1) according to the preceding claim, characterised in that said enclosure (2) is rotary about the longitudinal axis (X-X') thereof, the lifting means (16) comprising at least two rows (11) of contiguous lifting buckets, said buckets being distributed for each row (11) over at least the majority of the circumference of said enclosure (2), and being designed to lift the granular products travelling in said enclosure (2) during the rotation of the latter.
8. Treatment device (1) according to the preceding claim, characterised in that the enclosure (2) comprises an annular dam (12) for separating the rows (11) of buckets interposed between two contiguous rows (11) of buckets, said at least one annular dam (12) being designed to limit the travel of the granular products from one row (11) of buckets to another.
9. Treatment device (1) according to any one of the preceding claims, characterised in that it comprises a device for taking off the diverted flow (D) comprising:

   - at least one opening (13) for taking off the diverted flow (D) provided at the periphery of said enclosure (2) at the second branch (8B),

   - an annular skirt (14) extending between an interior edge (14A) and a free portion (14B), the annular skirt (14) being attached by the inner edge (14A) to the inside of said enclosure (2) upstream of said at least one takeoff opening (13) in terms of the direction of travel (C) of the granular products, the free portion (14B) covering at a distance at least the majority of said at least one takeoff opening (13),

   - at least one barrier blade (15) attached inside said enclosure (2), disposed in a helix with respect to the longitudinal axis (X-X'), and disposed downstream of said at least one takeoff opening (13) in terms of the direction of travel (C) of the granular products.
10. Treatment device (1) according to any one of the preceding claims, characterised in that the first branch (8A) is connected to said enclosure (2) at, or upstream of, the main inlet (3A) in terms of the direction of travel (C) of the granular products.
11. Method for regulating the temperature of volatile emanations produced by a device (1) for the hot treatment of granular products, of the gravel or aggregate type, comprising:

    - an enclosure (2) that is substantially cylindrical in shape overall, defining a longitudinal axis (X-X'), the enclosure (2) being provided, in the vicinity of one of the two ends thereof, with a main inlet (3A) for introducing granular products inside the enclosure (2), and being provided, in the vicinity of the other end, with an outlet (4) for extracting the granular products out of said enclosure (2), said granular products being intended to undergo treatment while travelling inside said enclosure (2) from the main inlet (3A) as far as the outlet (4) in a travel direction (C),

    - a heating means (5) that is situated inside said enclosure (2) and is designed to generate a drying flow (F) oriented in the opposite direction to the direction of travel (C), and passing through a drying section (6B) of the enclosure (2), the drying flow (F) being able to contribute to the drying of said granular products in the drying section (6B),

    - a main discharger (7A) of volatile emanations produced inside the enclosure (2), the main discharger (7A) being connected to said enclosure (2) by a first branch (8A), and being designed to discharge out of the enclosure (2) a main flow (P) of emanations,

    said method comprising a step during which a diverted flow (D) of emanations produced inside said enclosure (2) in the drying section (6B) is taken off, upstream of the first branch (8A) in terms of the drying flow (F), and during which the diverted flow (D) is transmitted to said main discharger (7A), the method being characterised in that it comprises a step during which the flow rate of the diverted flow (D) transmitted to the main discharger (7A) is increased or reduced according to the temperature of the main flow (P).
12. Regulation method according to the preceding claim, characterised in that the flow rate of the diverted flow (D) transmitted to the main discharger (7A) is increased when the temperature of said main flow (P) is lower than a set temperature, and in that the flow rate of the diverted flow (D) transmitted to the main discharger (7A) is reduced when the temperature of said main flow (P) is higher than the set temperature.
13. Regulation method according to either one of claims 11 or 12, characterised in that it comprises a step during which granular products resulting from the recirculation of bituminous products are introduced in said enclosure (2) between the main inlet (3A) and the outlet (4).
14. Regulation method according to the preceding claim, characterised in that the granular products resulting from the recirculation of bituminous products in the enclosure (2) are introduced between the place at which the diverted flow (D) is taken off and said heating means (5).

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