EP1934537B1 - Dual-compartment carbon dioxide snow receptacle for isothermal containers - Google Patents

Description

The invention relates to the field of transportation of perishable foodstuffs in isothermal containers, where the maintenance of the cold chain is provided by solid phase carbon dioxide ("dry ice").

Such isothermal containers commonly include a cryogenic compartment disposed in the upper part of the container, above the compartment where are placed the products to be kept at controlled temperature. The cryogenic compartment is materialized (by rails, a bottom wall, etc.) or not depending on the case.

Traditionally, this upper compartment receives a reservoir intended to contain a refrigerant, such as carbon dioxide in the solid phase, the sublimation of which releases cold gases compensating the heat input through the joints between the container and its door or to through the insulation of the container.

It is well known that the regulations in force concerning the respect of the cold chain for the transport of perishable foodstuffs are becoming more and more rigorous, and in particular are leading retail players to evolve in terms of product preparation and traceability. to carry.

However, it is also known that the directed temperature of the working premises as well as waiting quays intended for the loading of conditioned containers (in foodstuffs and refrigerating agent), requires a significant energy expenditure punctuated by a weak renewal of air in all transit areas of products.

Isothermal container structures are already known in which the cryogenic compartment, in which the cryogenic mass is stored, is provided with means (typically in the form of grids) making it possible to retain the charged carbon dioxide snow while allowing the gas to pass through, and so organize the fact that during the loading of the fluid reservoir, one proceeds to the recovery of gas in the ambience of the premises using an extractor. The document EP-631 096 illustrates this state of the art.

More recently, it has been proposed in the document EP-823,600 a container structure in which the storage tank of the cryogenic mass is slidably mounted in horizontal runners of the cryogenic compartment of the container, and where this tank is divided internally by such means for retaining dry ice in two zones, a zone storage of dry ice, connected to means for supplying liquid CO ₂ , and an expansion zone of the gas communicating with carbon dioxide suction means. The author of the document also insists a lot on the fact that the reservoir described is carbon dioxide tight to better isolate the product storage compartment of cold gases from either carbon dioxide sublimated by snow or air cooled by carbon dioxide. radiative action of this snow.

• tout d'abord le fait que le réservoir est étanche au gaz rend le conteneur inefficace pour sa mission de préservation de denrées alimentaires périssables, on comprend que dans cette configuration le compartiment cryogénique n'échange des frigories (froid) avec les produits qu'au travers de la paroi horizontale froide qui sépare les deux compartiments, ce qui est tout à fait insuffisant;
• d'autre part, on comprend bien que l'exploitation de ce système nécessite des conteneurs spécifiques (dédiés) avec une géométrie intérieure adaptée (plans de joint, rainures transversales ...) puisque également le conteneur lui même dans sa partie haute ( plafond ) joue un rôle en participant à la constitution de la zone de détente et permettre ainsi la récupération des gaz.

The work carried out by the Applicant has shown that the containers proposed by the latter document have the following drawbacks:

• first of all the fact that the tank is gas-tight makes the container ineffective for its mission of preservation of perishable foodstuffs, it is understood that in this configuration the cryogenic compartment exchange cold (cold) with products that through the cold horizontal wall that separates the two compartments, which is quite insufficient;
• on the other hand, it is understandable that the operation of this system requires specific containers (dedicated) with a suitable internal geometry (joint planes, transverse grooves ...) since also the container itself in its upper part (ceiling ) plays a role by participating in the constitution of the relaxation zone and thus allow the recovery of gases.

A tank according to the preamble of claim 1 is, for example, known from the document DE-A1-19808267 .

One of the objectives of the present invention is then to propose a new reservoir or receptacle of dry ice, which certainly makes it possible to recover the gases resulting from the injection of liquid CO ₂ and to route them outside the premises without modifying the environment. but also a reservoir that is autonomous that is to say that can adapt to any type of insulated container on the market, in standard version, and whose autonomy allows even the filling of the tank outside the container and the loading subsequent tank in the container.

• un bac de réception de neige carbonique, de forme sensiblement parallélépipédique, muni d'une part de moyens d'injection adaptés pour coopérer avec un injecteur relié à une source de CO₂ liquide et permettre l'injection de neige carbonique dans le bac, et d'autre part dont la face supérieure présente une zone de perforation apte à permettre l'évacuation du gaz généré à l'intérieur du bac; caractérisé par:
  • - un couvercle rendu solidaire de la face supérieure du bac de réception de façon à laisser entre la face supérieure et le couvercle un espace permettant l'accumulation du gaz généré; et
  • - la présence, sur l'une des faces latérales du bac de réception, desdits moyens d'injection et de moyens qui sont d'une part en communication avec ledit espace permettant l'accumulation du gaz généré et qui sont d'autre part adaptés pour coopérer avec des moyens extérieurs d'évacuation des gaz générés.

The work carried out by the Applicant has allowed it to demonstrate that this goal could be achieved by means of a cryogenic tank, able to contain a cryogenic mass and to be mounted in the cryogenic compartment of an isothermal storage container. and / or transporting perishable food products, the tank being provided with means for connection to a source of carbon dioxide in the liquid phase and separation means retaining the carbon dioxide snow but allowing the gas to pass, comprising:

• a carbon dioxide snow tray, of substantially parallelepiped shape, provided on the one hand with injection means adapted to cooperate with an injector connected to a source of liquid CO ₂ and to allow the injection of dry ice into the tank, and on the other hand whose upper face has a perforation zone adapted to allow evacuation of the gas generated inside the tray; characterized by:
  • - A lid made integral with the upper face of the receiving tray so as to leave between the upper face and the cover a space for the accumulation of the generated gas; and
  • the presence, on one of the lateral faces of the receiving tray, of said injection means and means which are on the one hand in communication with said space allowing the accumulation of the generated gas and which are on the other hand adapted to cooperate with external means of evacuation of the generated gases.

• le couvercle laisse en outre un espace pour permettre, en dehors des phases d'évacuation vers l'extérieur des gaz générés, le passage des gaz générés depuis le bac vers le compartiment de stockage des produits.
• le réservoir comprend un écran thermique en une matière thermiquement isolante, préférentiellement amovible, et apte à être installé sous le bac afin de protéger contre les rayonnements les denrées stockées dans le conteneur.
• les moyens d'injection sont adaptés pour coopérer avec un injecteur muni d'une buse de sortie de forme cylindrique à axe horizontal, s'étendant vers l'intérieur du bac, adapté pour orienter l'injection de neige carbonique sensiblement tangentiellement à une paroi latérale du bac de manière à créer un tourbillon dans le bac.

The tank according to the invention can also adopt one or more of the following technical characteristics:

• the cover also leaves a space to allow, outside of the phases of evacuation to the outside of the generated gases, the passage of gases generated from the tray to the product storage compartment.
• the tank comprises a heat shield made of a thermally insulating material, preferably removable, and able to be installed under the tray to protect the food stored in the container from radiation.
• the injection means are adapted to cooperate with an injector provided with a cylindrical shaped outlet nozzle with a horizontal axis, extending towards the inside of the tank, adapted to direct the injection of dry ice substantially tangentially to a wall side of the bin to create a vortex in the bin.

The invention also relates to an isothermal container for preserving and / or transporting perishable food products, of the type comprising a cryogenic compartment and a product storage compartment, as well as a cryogenic tank, suitable for being mounted in the cryogenic compartment, adapted for refrigerating the product storage compartment, characterized in that the cryogenic tank is in accordance with the tank according to the present invention.

As already mentioned above, the tank according to the invention is adaptable to all types of container, and the term "cryogenic compartment" must be understood to mean a space traditionally located in the upper part of the container, this space being or not materialized (by rails, a lower wall etc ...).

• la figure 1 est une représentation schématique partielle d'un réservoir conforme à l'invention ;
• la figure 2 est une représentation schématique partielle d'un réservoir conforme à l'invention permettant de visualiser un des modes d'injection mettant en oeuvre une buse de sortie de forme cylindrique à axe horizontal, s'étendant vers l'intérieur du bac, adaptée pour créer une structure de vortex ;
• la figure 3 est une représentation schématique partielle en coupe d'un conteneur équipé d'un réservoir conforme à l'invention.

Other characteristics and advantages will emerge from the following description, given solely by way of example and with reference to the appended figures in which:

• the figure 1 is a partial schematic representation of a reservoir according to the invention;
• the figure 2 is a partial schematic representation of a reservoir according to the invention for viewing one of the injection modes using a cylindrical shaped outlet nozzle with a horizontal axis, extending towards the inside of the tray, adapted to create a vortex structure;
• the figure 3 is a partial schematic sectional representation of a container equipped with a tank according to the invention.

We recognize on the figure 1 a partial schematic representation of a tank 1 according to the invention, comprising a carbon dioxide snow tray, of substantially parallelepiped shape, provided with a lid 2 and on the other hand whose upper face has a perforation zone 3 adapted to allow evacuation of the gas generated inside the tank. The figure 1 allows to visualize the perforation area in the form of a partial burst under the cover.

The front side of the tank is also shown the presence of a connector device comprising means 4 for injecting the cryogenic liquid into the tank, able to cooperate with external means for supplying cryogenic liquid (of the injection gun type ), and an opening 5, which is on the one hand in communication with the space between the tank and the lid, space which allows the accumulation of gases, and which is adapted to cooperate with external means of evacuation of generated gases (suction means coming to become solid with the opening 5).

• de créer une légère surpression résiduelle au sein du réceptacle, qui permet d'obtenir un tassement de la neige carbonique produite et donc d'améliorer la densité de la neige produite ;
• l'évacuation du gaz, ce qui permet d'obtenir un bon rendement de transformation.

The perforation zone is defined to allow:

• to create a slight residual overpressure within the receptacle, which makes it possible to obtain a settlement of the dry ice produced and thus to improve the density of the snow produced;
• evacuation of the gas, which makes it possible to obtain a good transformation yield.

The figure 2 is a partial schematic representation of a tank according to the invention for displaying one of the injection modes using an outlet nozzle 6 of cylindrical shape with a horizontal axis, extending towards the inside of the tank, and which is adapted to create a vortex structure 7. It has been found in practice that such a nozzle shape produces snow which is stored in a geometric Vortex motion by allowing nearly 90% of the volume of the receptacle to be occupied.

The figure 3 is a partial schematic sectional representation of a container equipped with a tank according to the invention, shown open door to view the mounting of the tank in the upper part of the container.

A thermal barrier 8 (here a polyurethane foam under plastic shell) is installed under the tank 1 to allow the protection of the fresh products that will be stored in the bottom of the container against radiation (it can be fixed or removable in the case of transport single frozen products)

The tank is self-contained and adaptable to all types of isothermal containers, it can be slid in horizontal slides provided in the walls of the cryogenic compartment of the container, or fixed by any other mode according to the request of the end user.

As will be understood from reading the above, unlike the prior art the tank here is not "sealed", it allows the escape of gases: when filling via the suction system that is branch on the front side, and in stable operation (food preservation) by the fact that the lid leaves a space not only above the upper face of the tray (which is provided with the mesh surface) but also in the front, to allow the gas, in operation, closed door, to reach the product storage compartment and perform its function of conservation / cooling products.

• le réservoir est autonome et adaptable à tous les types de conteneurs isothermes.
• il présente une capacité de chargement en neige carbonique et une vitesse de chargement en neige carbonique remarquable, atteignant jusque 15 kg de neige à la minute.
• la structure d'injection de type "vortex" ainsi que le dimensionnement de l'aire de perforation du séparateur Neige / Gaz spécifique permettent d'excellentes performances de ratio de transformation et de densité de neige formée dans le bac.
• on n'observe aucune modification d'atmosphère des locaux mettant en oeuvre le conteneur conforme à l'invention.

The advantages of the device according to the invention can then be summarized as follows:

• the tank is autonomous and adaptable to all types of insulated containers.
• it has a dry ice loading capacity and a remarkable dry ice loading speed of up to 15 kg of snow per minute.
• the "vortex" type injection structure and the dimensioning of the perforation area of the specific snow / gas separator allow for excellent conversion ratio and snow density performance in the tank.
• there is no change in the atmosphere of the premises using the container according to the invention.

Claims (5)

1. Cryogenic reservoir, adapted to hold a cryogenic mass and to be mounted in the cryogenic compartment of an isothermal container for preserving and/or transporting perishable food products, the reservoir being equipped with connecting means for connection to a source of carbon dioxide in the liquid phase and separating means retaining the carbon dioxide snow, but letting the gas pass through, comprising:

   - a substantially parallelepiped carbon dioxide snow receptacle, on the one hand equipped with injecting means adapted to engage with an injector connected to a source of liquid CO₂ and for injecting carbon dioxide snow into the receptacle, and on the other hand, the upper surface of which has a perforated zone for evacuating the gas generated inside the receptacle; characterised by:

   - a lid secured to the upper surface of the holding receptacle to allow a space for accumulating the generated gas between the upper surface of the receptacle and the lid; and

   - the presence, on one of the side surfaces of the receptacle, of said injecting means and means that on the one hand communicate with said space allowing for the accumulation of the generated gas and that on the other hand are adapted to engage with external means for evacuating the generated gases.
2. Cryogenic reservoir according to claim 1, characterised in that the lid further provides a space allowing for the generated gases to pass from the receptacle to the product storage compartment, outside of the external evacuation phases for the generated gases.
3. Cryogenic reservoir according to claim 1 or 2, characterised in that it comprises a heat shield made from a heat-insulating material, capable of being installed below the receptacle to protect the foods stored in the container against radiation.
4. Cryogenic reservoir according to claim 1 or 2, characterised in that the injecting means are adapted to engage with an injector equipped with a cylindrical output nozzle with a horizontal axis, extending inwards towards the receptacle, adapted to orient the injection of carbon dioxide snow substantially tangentially to a side wall of the receptacle so as to create a whirl in the receptacle.
5. Isothermal container for preserving and/or transporting perishable food products, of the type comprising a cryogenic compartment and a product storage compartment, as well as a cryogenic reservoir, capable of being mounted in the cryogenic compartment, adapted to cool the product storage compartment, characterised in that the cryogenic reservoir complies with any one of the previous claims.

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