Abstract:
A method and apparatus ( 22 ) for treating culinary gaseous effluents (Eg) carried in an air extraction duct of a kitchen, the apparatus includes:
       a unit ( 24 ) for storing in liquid form a nucleophilic active product (Pa), or odour destroyer, able to fix foul-smelling molecules in the form of inert salts,   a nebulizing and diffusing unit ( 26 ) which vaporizes or sublimates the active product (Pa) coming from the storage unit, and which diffuses the vaporized or sublimated active product (Pa) in an extraction duct ( 18 ), at ambient temperature, so as to minimize the discharge of foul-smelling molecules at the outlet of the extraction duct. A plant including this apparatus is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for treating culinary gaseous effluents carried in an air extraction duct of a kitchen. 
     2. Description of the Related Art 
     The present invention also relates to a plant for extracting air from a kitchen. 
     Anyone versed in the art of foul odour treatment will immediately recognize that the invention presented here in the form of the description of apparatus and the way said apparatus functions, also defines without ambiguity novel methods to execute the odour destruction that can be considered as well as novel inventions for which we seek patent protection. 
     In a kitchen, in particular in a professional catering kitchen or in an industrial culinary laboratory, the gaseous effluents produced by the culinary operations, in particular when cooking to food, are removed to the outside by means of an extractor hood and an air extraction duct which discharges outside the kitchen. 
     These gaseous effluents contain foul-smelling organic compounds such as ammonia (NH 3 ), sulphuric acid (H 2 S), mercaptans, fatty acids, etc. These foul-smelling molecules arise in particular from the combustion of plant and/or animal oils when, cooking food. 
     The presence of these foul-smelling molecules in the gaseous effluents is a considerable source of olfactory nuisance, especially for the surroundings located close to the region discharging the gaseous effluents. 
     The regulations applicable to kitchens in a professional environment are becoming increasingly restrictive on this subject. French Ministerial Decree (Ministry of Agriculture) of 9 May 1995, Part 1, Chapter 1, Article 3, paragraphs 2a and 2e may be quoted for example: “ . . . the (kitchen) premises must enable good hygiene practices to be implemented . . . in particular, to prevent . . . by ventilation . . . the persistence of bad smells . . . ”. 
     To solve the problem of these bad smells, it is known to use a perfumed or deodorizing chemical product, so as to mask the bad smells in the kitchen. However, this solution is not completely satisfactory since it leads to producing a mixture of smells which may prove to be unpleasant to smell. 
     Furthermore, the use of a deodorant in the kitchen entails risks to the food quality. Deodorant particles may be deposited on the food or on the cooking utensils, which may cause chemical contamination of the food, or at least impair its qualities of taste. 
     It is also known to fit, in the kitchen, filter systems, for example based on activated charcoal, or systems using ozone to destroy the organic compounds contained in the gaseous effluents. 
     These solutions are expensive and they require frequent maintenance operations. In addition, the efficiency of these solutions is not always satisfactory. 
     SUMMARY OF THE INVENTION 
     The invention aims to overcome these drawbacks in a simple, economic and efficient manner. 
     With this aim, the invention provides an apparatus for treating culinary gaseous effluents carried in an air extraction duct of a kitchen, characterized in that it comprises:
         a unit for storing, for instance in liquid form, a nucleophilic active product, or odour destroyer, able to fix foul-smelling molecules in the form of inert salts,   a nebulizing and diffusing unit which vaporizes or sublimates the active product coming from the storage device, and which diffuses the vaporized or sublimated active product in the extraction duct, at ambient temperature,   so as to minimize the discharge of foul-smelling molecules at the outlet of the extraction duct.       

     According to other features of the invention:
         the nebulizing and diffusing unit comprises a nebulizer which is supplied with compressed air by a compressor and which vaporizes or sublimates the active product in the form of fine droplets in suspension in a stream of compressed air;   the storage unit comprises a packaging container containing the active product which is accommodated in a detachable and complementary manner, in a housing, so as to put the inside of the container in communication with a buffer tank which is connected to the nebulizing and diffusing unit;   the container has the overall shape of a bottle, and the bottle is placed in the housing with its neck downwards;   the neck of the bottle is provided with a septum, before it is placed in the housing, and the housing comprises a tubular filling element complementary in shape to the neck, which is provided with means for piercing the septum, so as to put the inside of the bottle in communication with the buffer tank;   the housing comprises a duct which communicates with the atmospheric air and which emerges near the tubular filling element, so as to make it easier for the active product to flow into the tank by replacing the active product with air as it flows out;   the storage unit comprises means for determining the amount of active product stored;   the storage unit and the nebulizing and diffusing unit are arranged inside a control cabinet, and the nebulizing and diffusing unit is connected to the extraction duct via a diffusion duct;   the electrical elements of the nebulizing and diffusing unit are placed in a first compartment of the cabinet, and the other elements of the nebulizing and diffusing unit are placed, with the storage unit, in a second compartment of the cabinet;   the operation of the nebulizing and diffusing unit is tied to the operation of an extractor hood serving to extract air towards the extraction duct;   the nucleophilic active product is the product Nora Steam CM 8510 LO;   the method of nebulization used in the nebulizing unit is a dry vapour nebulization method.       

     It should be clear that neither the nucleophilic active product nor the method of nebulization that have been indicated are limitative of the scope of the present invention. The invention also provides a plant for extracting air from a kitchen comprising an extractor hood which is equipped with a filter, and an extraction duct which routes the culinary gaseous effluents from the extractor hood to the outside, characterized in that it comprises an apparatus according to one of the previous features. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the invention will become apparent on reading the following detailed description, for an understanding of which reference may be made to the appended drawings in which: 
         FIG. 1  is a diagram which shows a kitchen equipped with a plant and an apparatus made according to the teachings of the invention; 
         FIG. 2  is a vertical sectional view which schematically shows the apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a professional kitchen  10  which comprises cooking appliances  12  able to produce culinary gaseous effluents Eg when producing culinary preparations. 
     Conventionally, the kitchen  10  is equipped with a plant  14  for extracting air. 
     This plant  14  comprises an extractor hood  16  which extracts the gaseous effluents Eg from the kitchen  10  in order to discharge them outside EXT through an extraction duct  18 . 
     The plant  14  comprises a filter which is inserted between the hood  16  and the extraction duct  18  so as to retain some of the oil particles in suspension in the gaseous effluents Eg. 
     According to the teachings of the invention, the plant  14  comprises an apparatus  22  which treats the gaseous effluents Eg by diffusing an active product Pa into the extraction duct  18 , so as to minimize the discharge of foul-smelling molecules at the outlet of the extraction duct  18 . 
     In  FIG. 1 , the gaseous effluents which are emitted outside EXT, after treatment, are referenced Eg′. 
     The active product Pa, or odour destroyer, is a nucleophilic product able to fix foul-smelling molecules contained in the gaseous effluents Eg in the form of inert salts. 
     Such an active product Pa generally consists of organic groups from the carboxylase family, which react chemically and irreversibly with foul-smelling organic compounds, especially with sulphur compounds and with nitrogen compounds, thereby producing water-soluble, stable, non-toxic and inert salts. 
     Preferably, the product “NORA STEAM® CM 8510 LO”, marketed by Phodé, 25 rue Jean Rostand, zone artisanale Val de Caussels, 81000 Albi, France, is used. The type and brand of active products that have been specified should however not be understood as limitative of the scope of the present invention. 
     The apparatus  22  according to the invention is shown diagrammatically in a more detailed manner in  FIG. 2 . 
     As may be observed in  FIG. 2 , the apparatus  22  comprises a storage unit  24  and a nebulizing and diffusing unit  26 . 
     The storage unit  24  comprises a packaging container  28  containing the active product Pa in liquid form. 
     The packaging container  28  is accommodated in a detachable and complementary manner in a housing  30 , so as to put the inside of the container  28  in communication with a buffer tank  32  which is connected to the nebulizing and diffusing unit  26 . 
     In this case, the packaging container  28  has the shape of a bottle which is arranged vertically in the housing  30 , with its neck  34  extending downwards. 
     Preferably, the bottle  28  is equipped, during its packaging, with a cap and a safety ring (not shown), for example of the same type as those which are used for packaging mineral water in a plastic bottle. 
     The safety ring remains in place on the bottle  28 , when the cap is removed, which makes it possible to distinguish a new bottle  28  from a bottle which has already been opened at least once. 
     In vertical section and according to the embodiment shown here, the buffer tank  32  is in the form of a capital “L”-shaped chamber. The buffer tank  32  therefore comprises a vertical parallelepipedal main portion or arm  36  and a lower horizontal parallelepipedal side portion or arm  38  which has a height less than the main portion  36 . 
     In this case, the housing  30  is placed on the upper wall  40  of the side portion  38  of the buffer tank  32 . It comprises a vertical cylindrical tubular element  42  which leads into the buffer tank  32 , via a filling orifice  44  made in the upper wall  40  of the side portion  38 . 
     The inside diameter of the tubular element  42  is slightly greater than the outside diameter of the neck  34  of the bottle  28 , so as to accommodate it in a substantially complementary manner, and so that the connection between the neck  34  and the housing  30  is leaktight. 
     Note that the neck  34  of the bottle  28  may be screwed into the housing  30 , or else be fitted into the housing  30 , for example using a mounting of the bayonet type. 
     Preferably, the housing  30  is equipped with a perforating device  46 , which is shown in  FIG. 2  in the form of a rod whose upper end is pointed, and which extends vertically upwards, inside the tubular element  42 . 
     The reason for this is that when the active product Pa is packaged in the bottle  28 , before the bottle  28  is put in place in the housing  30 , the neck  34  is closed off by a septum  48 , or membrane. 
     The rod  46  therefore makes it possible to perforate the septum  48 , after the bottle  28  is put in place in the housing  30 , so as to put the inside of the bottle  28  in communication with the inside of the buffer tank  32 . 
     In  FIG. 2 , since the bottle  28  is shown put in place in the housing  30 , that is to say in the mounted position, the septum  48  is shown in the perforated state. 
     Advantageously, the housing  30  also comprises an air duct  50 , a first end  52  of which is placed inside the tubular element  42 , with its opening upwards, and a second end  54  of which is placed outside the housing  30 . 
     The second end  54  of the air duct  50  is placed at a height greater than the height of the bottle  28  in the mounted position, so as to route the air at atmospheric pressure into the bottle  28 , as the bottle  28  gradually empties into the buffer tank  32 . 
     Note that the first end  52  of the air duct  50  is in this case bevelled, so as to form a second perforation means with the rod  46 . 
     According to a variant embodiment (not shown), guiding means may be provided to make it easier to put the bottle  28  in the housing  30 . 
     Advantageously, the buffer tank  32  comprises means  56  for determining the amount of active product Pa stored. In this case, these means consist of a sensor  56  comprising a dip tube which is placed in the tank  32 , close to the bottom wall  58  of the tank  32 . 
     The sensor  56  is able to transmit an electric signal, when the level of active product Pa in the tank  32  reaches a critical value, less than a minimum predetermined value. 
     The nebulizing and diffusing unit  26  will now be described. 
     In this case, the nebulizing and diffusing unit  26  comprises a nebulizer  60 , or atomizer, which vaporizes the active product Pa in the form of an aerosol, that is to say in the form of a “cloud” of active product Pa called an active mist Ba, consisting of fine droplets in suspension in the air. 
     Note that the nebulizer  60  operates at room temperature, without it being necessary to provide means for heating the active product Pa. 
     Advantageously, a nebulizer  60 , like those which are employed for aerosol therapy, in order to administer drugs into the respiratory tract of a patient, is used. 
     This type of nebulizer  60  especially makes it possible to produce fine droplets of active product Pa, that is to say droplets whose size is of the order of a few micrometres. 
     The active product can also be sublimated instead of vaporized. 
     The active product can also be stored in a non liquid form. 
     Now, the smaller the droplet size, the greater the surface area of exchange between the active product Pa and the foul-smelling molecules to be treated, which makes it possible to obtain very fast chemical reaction kinetics. 
     However, the regulations currently in force, relating to chemical products likely to be inhaled, impose a particle size greater than 5 micrometres. It is therefore necessary to use a nebulizer  60  which guarantees compliance with these regulations by producing droplets of active product Pa whose size is greater than 5 micrometres. 
     For example, the pneumatic nebulizer “Atomisor NL7 BSDG”, marketed by Diffusion Technique Française SARL, 120 rue Bergson, 42003 Saint-Etienne, France, is used. 
     By suitable adjustment, this nebulizer  60  makes it possible to comply with the regulations with respect to particle size, while producing fine droplets which optimize the efficiency of the active mist Ba. 
     Here, the nebulizer  60  is placed on the upper wall  62  of the main portion  36  of the buffer tank  32 . The nebulizer  60  is supplied with active product Pa via a first feed line  64 , which extends inside the buffer tank  32 , through the upper wall  62 , almost down to the bottom wall  58  of the buffer tank  32 . 
     The nebulizer  60  is also supplied with compressed air Ac via a second feed line  66 . 
     Here, the compressed air Ac is produced, from atmospheric air, by an electric compressor  68  which is connected to the second feed line  66 . 
     Advantageously, a compressor  68  of the type which is usually coupled with a nebulizer  60  in therapeutic applications and which makes it possible to obtain a pressure greater than 50 bar, is used. 
     The compressed air stream Ac produced by the compressor  68  flows through the nebulizer  60  and is then sent to the extraction duct  18 , via a diffusing duct  70 . 
     While flowing through the nebulizer  60 , the compressed air stream Ac sucks the active product Pa up, by means of the Venturi effect, and transports the droplets of active product Pa into the diffusing duct  70 . 
     The diffusing duct  70 , which connects the nebulizer  60  to the extraction duct  18  and which leads into the extraction duct  18  via a hole  72 , therefore makes it possible to route the active product Pa, in the form of an active mist Ba, to the extraction duct  18 . 
     The method of nebulization used here is called dry vapour nebulization, that is to say that, since the size of the droplets is very small, the active mist Ba has virtually no effect on the hygrometry of the gaseous effluents Eg in the extraction duct  18 . 
     Advantageously, the storage unit  24  and the nebulizing and diffusing unit  26  are placed inside a control cabinet  74 . 
     The control cabinet  74  is preferably made of stainless steel. 
     In  FIG. 2 , the cabinet  74  is shown with its door  86  in the open position. 
     Preferably, the cabinet  74  comprises an inner separating partition  75  which defines a first compartment  76  in which the electrical elements of the apparatus  22  are placed, and a second compartment  78  in which the non-electric elements of the atomizing and diffusing unit  26 , and the storage unit  24 , are placed. 
     This separation makes it possible to limit the risk of electrical accidents, especially when handling the active product Pa which is in liquid form. 
     According to the embodiment shown here, the first compartment  76  contains the electric compressor  68  and a control unit  80 , which is in particular connected to the compressor  68 , to the sensor  56 , and to an electrical power supply device  82 . 
     The electrical supply device  82  consists, for example, of the electrical supply network (not shown) of the kitchen  10 . 
     Here, the control unit  80  is connected to a series of switches  84 , which are placed on the outer face of the door  86  of the cabinet  74 , and which make it possible, in particular, to start and stop the apparatus  22 . 
     Advantageously, the operation of the apparatus  22  according to the invention is tied to the operation of the extractor hood  16 . 
     According to the preferred embodiment of the invention, the apparatus  22  operates continuously with the extractor hood  16 , such that the start-up or shutdown of the hood  16  triggers the start-up or shutdown, respectively, of the apparatus  22 . 
     The operation of the apparatus  22  and of the plant  14  according to the invention is as follows. 
     Initially, during the first use of the apparatus  22 , a user pours active product Pa into the buffer tank  32 , by means of the bottle  28 . 
     For this purpose, the bottle  28  is mounted in its housing  30 , until the rod  46  and the end  52  of the air duct  50  perforate the septum  48  which closes the neck  34 . 
     As soon as the septum  48  is perforated, the active product Pa pours into the buffer tank  32 , until the bottle  28  is empty, or until the liquid levels in the tank  32  and in the bottle  28  come into equilibrium, as in  FIG. 2 . 
     During this operation, the air duct  50  provides the inside of the bottle  28  with air, so as to replace the product Pa which has flowed out, thereby making it easier for the product Pa to flow into the tank  32 . 
     Note that the bottle  28  may remain in place in the housing  30  until it is empty and/or it is replaced. 
     When the bottle  28  is empty, it can be replaced by a new bottle  28 , without the supply of active product Pa to the apparatus  22  being cut off, in so far as the buffer tank  32  still contains active product Pa. 
     Once the buffer tank  32  contains active product Pa, the apparatus  22  is ready to operate. 
     When the cooking appliances  12  are used, the hood  16  is switched on, which automatically causes the compressor  68  of the apparatus  22  to start up. 
     The flow of the compressed air stream Ac, produced by the compressor  68 , in the second feed line  66 , causes, in the nebulizer  60 , the active product Pa to be sucked up through the first feed line  64 , and the active product Pa to be vaporized in the compressed air stream Ac. 
     The nebulizer  60  produces, in the diffusing duct  70 , an active mist Ba, which is made up of droplets of active product Pa in suspension in the compressed air stream Ac. 
     The diffusing duct  70  routes the active mist Ba to the extraction duct  18  of the hood  16 , where the particles of active product Pa react with the foul-smelling molecules contained in the gaseous effluents Eg. 
     The reaction of the active product Pa with the foul-smelling molecules produces inert salts, mainly in the form of volatile particles which are removed with the treated gaseous effluents Eg′ outside EXT the kitchen  10 . 
     The apparatus  22  and the plant  14  according to the invention therefore make it possible to treat the gaseous effluents Eg emitted in the kitchen  10 , so as to discharge to the outside EXT gaseous effluents Eg′ comprising very few foul-smelling molecules. 
     Chromatographic analyses have shown that the majority of sulphur or nitrogen molecules or the like, which are responsible for bad cooking smells, have disappeared. 
     It is possible to obtain an efficiency of treatment of the foul-smelling molecules of 85 to 100%, depending on the type of molecule and on their concentration in the gaseous effluents Eg. 
     The efficiency of the system is in particular associated with the dimensions of the droplets of active product Pa. The dimensions of the droplets are conditioned by the operating pressure of the nebulizing and diffusing unit  26 , by the diameter and by the structural properties of the orifice of the nozzle (not shown) fitted to the nebulizer  60  and which vaporizes the active product Pa into the compressed air stream. 
     Note that the apparatus  22  and the plant  14  according to the invention do not diffuse active product Pa into the ambient air of the kitchen  10 , but directly inside the extraction duct  18 . This especially makes it possible to prevent the contamination of food or of culinary containers by the active product Pa. 
     The diffusion of the active mist Ba in the extraction duct  18  may lead to a light deposit of active product Pa on the inner walls of the extraction duct  18 . This deposit contributes to the efficiency of treatment of the gaseous effluents Eg, by maximizing the surface area of exchange between the active product Pa and the foul-smelling molecules. 
     The packaging of the active product Pa in a bottle  28  closed by a septum  48 , and the way it is placed in the storage unit  24 , allows easy and safe handling of the active product Pa, which avoids the risks of food contamination. 
     Furthermore, because the elements of the apparatus  22  according to the invention are placed in a closed cabinet  74 , use of the active product Pa and treatment of the gaseous effluents Eg is made easier, and the maintenance operations are reduced.