EP0823600B1 - Isothermal container with cold storage - Google Patents

Description

The invention relates to insulated containers comprising, as described in document FR-A-2 721 382 with respect to which claim 1 has been delimited, a cryogenic compartment disposed in the upper part of the container, above a compartment storage receiving products to be stored at constant temperature.

Currently, this compartment receives a reservoir, for example in the form of a drawer mounted sliding on slides and intended to contain a refrigerant, such as carbon dioxide in solid phase, that is to say in snow, granules or bread, of which sublimation releases cold gases compensating for the heat input through the joints between the container and its door and through the insulation of the container.

Such tanks must be able to ensure the conservation of fresh products at a positive temperature of the order of +1 to +4 ° C, but also that of frozen products at negative temperature of the order of -20 ° C.

To prevent the fresh products placed near the tank from being frozen by the air which cools on contact, whose interior is at -80 ° C, it is necessary to take precautions and, in the case of a tank metallic, as described in FR-A-2 626 554, a screen made of insulating material is added below the tank. When the tank is made of insulating material, as described in US 1,998,681 and FR-A-2,721,382, the bottom of this tank extends beyond the dimensions of the tank to form a screen.

In containers used in storage and dispatch centers food products for distribution to points of sale, it is also in addition makes use of carbon dioxide injected in liquid phase in the tank, so as to form, in this reservoir and by expansion of the liquid, a quantity of snow carbon dioxide dosed according to the season and the expected duration of conservation.

This implies that the tank resists the force of the jet of gas and snow and has means allowing the evacuation of gas, as well as means retaining the snow, as described in US 1,876,915 and EP-A-591,047.

It is here, during the fluid loading phase of the reservoir cryogenic, to evacuate the excess gas out of the tank and the container, and not as described in FR-A-2 721 382, during the conservation phase, control and channel the gas formed by the sublimation of this cryogenic fluid in the tank to diffuse frigories in the storage compartment.

Due to these various constraints during loading , the tanks currently sold are heavy and expensive, which has the disadvantage of limiting the application of this preservation technique, even though the need is growing to meet the regulations imposing a constant temperature storage, in what is known as the cold chain, between the warehouse and the place of sale of fresh or frozen food products.

To these disadvantages, we must add those resulting from the injection of dioxide carbon in the liquid phase in the cryogenic compartment. Indeed, this injection generates, in addition to carbon dioxide snow, a high emission of carbon dioxide may be harmful to personnel continuously loading the compartments of multiple containers. If this gas can be evacuated by an extractor hood, its free outlet compartment damages the staff working environment.

In addition, the gas evacuated in pure loss, because it is not recovered, is mixed with the air local, generally air conditioned, which leads to losses of heat energy.

The object of the present invention is to remedy these drawbacks by providing an inexpensive insulated container with cryogenic compartment to achieve, low height, ensuring good diffusion of frigories, resistant to injection of carbon dioxide, which can be used to maintain the temperature fresh and frozen products, and reducing carbon dioxide emissions when loaded.

• une zone de stockage de la neige carbonique communiquant par un canal d'alimentation avec le moyen de raccordement à la source de dioxyde de carbone en phase liquide,
• et une zone de détente du gaz communiquant avec un canal d'aspiration qui, ménagé dans la paroi frontale du réservoir, à distance du canal d'alimentation, est muni de moyens de raccordement à un conduit d'aspiration du gaz carbonique.

According to the invention defined in the claims, the reservoir of the cryogenic compartment is impermeable to carbon dioxide and is divided internally by the means retaining the carbon dioxide snow and letting the gas pass, by:

• a carbon dioxide snow storage area communicating via a supply channel with the means of connection to the source of carbon dioxide in the liquid phase,
• and a gas expansion zone communicating with a suction channel which, formed in the front wall of the tank, at a distance from the supply channel, is provided with means for connection to a suction pipe for carbon dioxide.

With this arrangement, during the loading of the tank, by injection of carbon dioxide in liquid phase, the tightness of the tank confines the excess gas in this compartment, which avoids its dilution in the ambient air, ensures the protection of the personnel and reduces the energy consumption of air conditioning in the room staff. This gas which expands in the compartment is immediately evacuated by the suction line connected to the compartment and can thus be reconditioned without intermediate treatment. This recovery reduces pollution and the cost of the operation.

Advantageously, the reservoir consists of the entire compartment cryogenic and is delimited by the walls of the container and, on the one hand, by a wall horizontal and insulating, separating this compartment from the storage compartment, and whose edges, respectively, side and rear, are engaged in slides, respectively side and rear of the container, to provide support, insulation and gas tightness, and, on the other hand, by an anterior vertical wall which, insulating and integral with the previous one, fits into an anterior recess of the container and is crossed by the supply channel and by the suction channel, these two walls being monolithic and forming a removable drawer.

This arrangement reduces the size of the compartment cryogenic and consequently increase the loading volume of the compartment conservation.

In one embodiment, the horizontal wall constituting the bottom of the tank supports a wire mesh basket which, internally lined with a tablecloth porous to gas but not to snow; is spaced from all the neighboring walls of the container, extends transversely only over part of the transverse dimension of the anterior wall, in the zone of this wall traversed by the supply channel, to form, opposite the suction channel, the gas expansion compartment.

In the case of storage of fresh products at a temperature between 0 ° C. and + 4 ° C, the insulation and tightness ensured by the engagement in the slides of edges of the horizontal wall of the drawer, effectively protect the products placed in the preservation chamber against the action of cold gases, while this wall horizontal limits the radiative action and ensures sufficient and regular diffusion, allowing, for an equal shelf life, to reduce the necessary amount of snow carbonic, therefore the energy cost of maintaining a cool temperature.

In another embodiment, the tank consists of a tank metallic parallelepipedic whose bottom rests on a horizontal and insulating wall which, separating the cryogenic compartment from the preservation compartment, is engaged by its edges, respectively lateral and rear, in support slides, of insulation and sealing, respectively lateral and rear of the container, this tank being provided with a front opening which is fitted and fixed on the back of a vertical wall anterior, insulating, integral with the horizontal wall and fitting into a container recess, this wall being traversed by the gas supply channel carbonic and through the suction channel and carrying, in the extension of this channel of suction, a blind cuff which, constituted by a porous sheet of gas but no to snow, extends into the bin.

This arrangement has the advantage of withstanding pressure without problem injection, to simplify the division of the cryogenic compartment into two volumes reserved, one for dry ice, the other for carbon dioxide and to facilitate recovery of excess gas.

To better isolate the cold gas storage compartment, either from carbon dioxide sublimated by snow, or from air cooled by the action radiative to this snow, the horizontal wall is surrounded by a seal at the gases whose lateral and rear sections cooperate with the bottoms of the slides, respectively side and rear of the container and whose front section, projecting from the vertical front wall, cooperates with the front part of the container.

Furthermore and to allow, from the same tank, conservation fresh and frozen products, the upper part of the container contains, laterally, on each side and in its rear wall, two superimposed slides, able to receive, the lower ones, the edges of the horizontal wall of the drawer when it is in the conservation position for fresh products, and those above, these same edges, but when the drawer is turned 180 ° with the tray facing down.

Figure 1 est une vue partielle en perspective éclatée montrant les différents éléments composant la réserve à frigories,

Figure 2 est une vue partielle en coupe transversale,

Figures 3 et 4 sont des vues partielles en coupe longitudinale,

Figure 5 est une vue en coupe transversale d'une variante de réalisation du réservoir,

Figure 6 est une vue en perspective avec coupe partielle d'une autre forme d'exécution du réservoir,

Figure 7 est une vue en coupe longitudinale du bac de figure 6,

Figure 8 est une vue en coupe transversale d'une variante de réalisation de ce réservoir,

Figure 9 est une vue partielle en perspective montrant une variante de réalisation de la manchette disposée dans le bac,

Figures 10 et 11 sont des vues en coupe transversale d'une autre forme d'exécution du conteneur et du réservoir, lorsque le réservoir est, respectivement, en position de conservation de produits frais et en position de conservation de produits surgelés.

Other advantages will emerge from the description which follows with reference to the appended diagrammatic drawing representing, by way of example, several embodiments of the reservoir according to the invention.

FIG. 1 is a partial exploded perspective view showing the various elements making up the cold store,

FIG. 2 is a partial view in cross section,

Figures 3 and 4 are partial views in longitudinal section,

FIG. 5 is a cross-sectional view of an alternative embodiment of the reservoir,

FIG. 6 is a perspective view with partial section of another embodiment of the reservoir,

FIG. 7 is a view in longitudinal section of the container of FIG. 6,

FIG. 8 is a cross-sectional view of an alternative embodiment of this tank,

FIG. 9 is a partial perspective view showing an alternative embodiment of the cuff arranged in the tray,

Figures 10 and 11 are cross-sectional views of another embodiment of the container and the tank, when the tank is, respectively, in the fresh product storage position and in the frozen product storage position.

In this drawing, the reference numeral 2 generally designates a insulated container comprising two longitudinal slides 3 intended to cooperate with a tank 4 of a refrigerant mass. The side walls 5a, posterior 5b, the roof 5c and the bottom 6 of the container are composed of an inner skin and a skin exterior trimmed with insulation. These skins can be formed by a laminate glass-resin or by a polyethylene layer participating in the formation of a hollow envelope obtained by rotational molding or equivalent. On its front side, the container comprises in recess 7 for the reception of a front door 9 swivel with seals.

The tank 4 is composed of an insulating bottom wall and rectangular 10 and a front wall 12 which, also insulating and rectangular, is perpendicular to it to form with it a sort of L-shaped drawer. longitudinal 13 of the bottom wall 10 have a thickness allowing them to slide in the slides 3 of the container, while the rear edge 14, of the same thickness, is intended to engage in a dorsal slide 8 formed in the container, at same level as the rails 3.

Figure 1 shows that, for certain applications, the slides 3 and 8 are provided with seals 15 limiting the heat exchanges between the cryogenic compartment upper A and the lower storage compartment B, and ensuring the cold gases between these two compartments.

The walls 10 and 12 constituting the drawer are monolithic and are consisting of a hollow plastic casing filled with insulation, casing obtainable by injection blow molding, rotational molding or equivalent.

Figures 1 and 2 show that the front wall 12 of the drawer fits in a recess 16, made in the bottom of the recess 7 for the door.

In the embodiment of Figures 1 to 4, the upper wall 10 of the drawer 4 supports a wire mesh basket 17 composed of longitudinal metal wires 18 welded on double sleepers 19. These sleepers have lateral returns bent 20, fitted at their ends with bent legs 22. FIG. 3 shows that certain longitudinal members are also extended towards the rear by bent returns 23, bearers of bent legs 24, and on the front by bent legs 25. The different tabs 22, 24 and 25 cooperate with screws to fix the basket 17 on the wall lower 10 and on the front wall 12 of the drawer.

This basket is lined internally with a textile tablecloth 26, porous with gas. but not carbon dioxide snow. This tablecloth can be constituted by an envelope parallelepiped with an opening communicating with the channel 27 described further.

The dimensions of the basket 17 are such that, except on the front where it rests on the front wall 12, all of its other faces are spaced by a value e from the walls Sa, 5b, 5c, but that on the other hand, one of the sides of the tank is spaced from one of the side walls Sa of the container by a greater distance d . This makes it possible to constitute, in compartment A, a storage area C for dry ice and a relaxation area D, the usefulness of which will be specified below.

In its part adjoining the basket 17, the wall 12 is crossed by a channel 27 (Figure 3) provided with connection means with the end piece 28 of a source of carbon dioxide, for example from a loading pistol. This wall 12 comprises, in its part adjoining the expansion compartment D, a channel 29 which, from larger diameter than that 27, is provided with connection means 30 to a carbon dioxide suction line 31. These connection means 30 can also cooperate with a sealing plug, not shown.

When the drawer, carrying the basket 17 and the ply 26, is put in place the upper part of the container, it forms an isothermal enclosure since all walls surrounding compartment A are lined with insulation. This set is held in position by means of screws 32 passing through the wall by suitable channels rear 5b of the container and screwing into threaded inserts 33 opening from the edge posterior of the wall 12 and by screws 34 passing through the wall by appropriate channels front 12 and screwing into threaded inserts 35 formed in the front part of the container. These different screws prevent the drawer from moving during transport and, consequently, cold gas leaks, and are sufficient to maintain the drawer, despite the reaction forces acting on it during the injection of carbon dioxide in the liquid phase by means of the nozzle 28. During this injection, the dioxide relaxes inside the basket 17 and forms snow which is retained by the sheet 26 and therefore accumulates inside the basket. Excess gas passes through the water table porous with gas 26 and this all the more easily as its flow beyond this sheet is not braked thanks to the spaces e formed between it and the walls of the container. The gas thus comes into the expansion space D where it is sucked in through the conduit 31.

At the end of loading, the end piece 28 is disconnected, as is the conduit 31, and the channel 29 is closed by a plug.

The reservoir according to the invention is much less expensive to produce than a metal tray and, by the presence of the insulating walls 10 and 12, eliminates any recourse to screens to control the spread of frigories, and more precisely to control the emission of cold gases.

Figure 5 shows an alternative embodiment of this tank designed for conservation of fresh products, intended to also allow their use for the conservation of frozen products. To this end, the horizontal wall 10 is covered, at less in its internal part to the container, by a metal wall 1 and the wall 10 is provided with an opening 21 opening onto the front. This opening, which is arranged under the basket 17 has on each of its lateral edges and on its rear edge, a groove, or a rib, able to cooperate with a rib, or a groove, formed on the edges, respectively, side and rear of a removable insulating panel 31. When this panel is removed, the metal wall 11 diffuses by direct radiation into the storage compartment B. For storage of fresh produce, simply replace the insulating panel 31 in the slides of the opening 21.

In the description which follows, the parts common to the embodiment previous will bear the same references, the new elements being referenced to from 32.

In the embodiments of FIGS. 6 to 11, the reservoir comprises, in complement of the drawer, a parallelepiped metal tray 32, such as steel stainless. This tray is provided with a front opening 33 through which it fits on a boss 34 projecting from the rear face of the wall 12, as shown in FIG. 7. Sa connection with the drawer is ensured by screws 35. The bottom wall 32a of the tank 32 rests on the bottom 10 of the drawer. Its edge is provided with a seal 36 which engages in a groove 37 formed between the boss and the upper face of the bottom 10. To withstand the pressure injection, the walls, respectively, lower 32a and upper 32b of the tank, are connected by tie rods 38.

In this embodiment, the suction channel 29 is crossed by a cuff 39 which is blind at one end and fitted, by its other end, onto a flange 40, itself fixed by screws 42 in a recess emerging from the outer face of the front wall 12.

The cuff 39 is produced in a ply which, textile or metallic, is porous to gas and not to dry ice. This tablecloth is cylindrical but can also, as shown in figure 9, be constituted by a metallic filter cartridge 39a shaped with radial folds and having a large exchange surface.

When carbon dioxide in liquid phase is injected through channel 27, the gas which expands inside the tank 32 forms carbon dioxide snow. His part excess crosses the membrane 39 where it is sucked in through the suction pipe connecting to the flange 40.

In the embodiment shown, the horizontal wall 10, constituting the bottom of the tank is surrounded by a seal 43, which therefore extends over the edges, respectively longitudinal and posterior of this wall, but also on its edge anterior joint with the front wall 12. This seal is arranged in a groove which positions. Figure 7 shows that when the front door 9 is closed, it comes contact with seal 43 and thus the entire compartment A is separated from the storage compartment B by a watertight barrier.

In a preferred embodiment, the seal 43 is constituted by a flange inflatable whose valve 44 is disposed, as shown in FIG. 6, in a knockout 45 emerging from the front face of the front wall 12. Thus, after installation of the drawer in the upper cryogenic compartment A, the operator inflates the seal 43 using a fluid such as compressed air. Thanks to this inflation, the seal comes in contact with the bottom of the grooves constituting the slides 3 and 8 and ensures perfect tightness, whatever the dimensional variations of these grooves and of the drawer. Another advantage of this seal is that it ensures the translational wedging of the drawer by report to the container. Obviously, to remove the drawer, you must first deflating the seal by acting on valve 44.

Figure 8 shows another embodiment of the tank of Figure 6 allowing a current container equipped with a single level of slides 3 and 8 to be able use the same drawer to ensure the conservation of fresh products and conservation frozen products. The bottom 10 of the drawer is crossed by an opening 46 opening on the front and giving it the shape of a U-shaped frame. The internal edges of this frame are provided with guide and insulation slides 47 formed by ribs or grooves, able to cooperate with grooves or ribs formed on the edges correspondents of a removable and insulating panel 48.

When the panel 48 is placed in the opening 46, the container is similar to that described above, i.e. has an insulating bottom which limits the diffusion of cold towards storage compartment B. When the same container must be used for the storage of frozen products, panel 48 is took of. Under these conditions, cold transmission takes place directly from the wall bottom of metal tray 32 towards compartment B.

Figures 10 and 11 show the application of the reservoir described with reference in FIGS. 6 and 7 to a container 2a fitted, in addition, with the lower slides, longitudinal 3 and dorsal 8 respectively, of upper slides 3a and 8a.

So, as shown in figure 10, for the conservation of fresh products, the reservoir is arranged as in the embodiment shown in FIGS. 6 and 7, that is to say with the tray 32 above the bottom 10 of the drawer. However, for the conservation of frozen products, as shown in figure 11, the whole is turned upside down and the horizontal wall 10 of the drawer is arranged in the slides 3a, 8a with the bin 32 below it. Under these conditions, the seal 43 is not necessarily inflated.

This simple device allows very quickly to modify the conditions of conservation of a cryogenic tank container.

• avec le même encombrement que les bacs actuels, il permet d'augmenter le volume disponible pour le stockage de la neige carbonique,
• il s'adapte sur les conteneurs existants et est amovible et interchangeable,
• grâce à son étanchéité, il permet de récupérer le gaz carbonique excédentaire, sans que celui-ci puisse se mélanger avec l'air ambiant, ce qui permet le recyclage de ce gaz et réduit la consommation d'air frais dans les locaux climatisés,
• le gaz récupéré peut aussi être utilisé pour refroidir la ligne d'alimentation en gaz liquide, ce qui permet d'améliorer la quantité de neige produite et le rendement par kilogramme de gaz liquide,
• la division du réservoir étanche par une nappe poreuse au gaz mais retenant la neige, évite que des particules de neige soient emportées par le gaz et améliore, de l'ordre de 20 à 30 %, la quantité de neige produite, donc le rendement général de la recharge en frigories.
• le réservoir étanche et l'aspiration préservent l'opérateur et l'environnement en réduisant les émissions de gaz carbonique pendant le remplissage du bac,
• le réservoir résiste à la pression d'injection, de l'ordre de 20 bars et peut être rechargé indéfiniment,
• et il assure une excellente diffusion du froid qui est régulière et n'altère pas les produits frais disposés dans le compartiment de conservation.

In its various embodiments, the cryogenic tank according to the invention has the following advantages:

• with the same size as the current tanks, it allows to increase the volume available for the storage of dry ice,
• it adapts to existing containers and is removable and interchangeable,
• thanks to its tightness, it makes it possible to recover the excess carbon dioxide, without it being able to mix with the ambient air, which allows the recycling of this gas and reduces the consumption of fresh air in air-conditioned premises,
• the recovered gas can also be used to cool the liquid gas supply line, which improves the amount of snow produced and the yield per kilogram of liquid gas,
• the division of the sealed reservoir by a porous sheet of gas but retaining snow, prevents snow particles from being carried away by the gas and improves, by around 20 to 30%, the amount of snow produced, therefore the overall yield of the refill in frigories.
• the sealed tank and the suction protect the operator and the environment by reducing carbon dioxide emissions during the filling of the tank,
• the reservoir withstands the injection pressure, of the order of 20 bars and can be refilled indefinitely,
• and it ensures an excellent distribution of the cold which is regular and does not alter the fresh products placed in the preservation compartment.

Claims (10)

1. An isothermal container (2) with a cryogenic compartment (A) disposed above a compartment (B) for conserving fresh or frozen produce, the said cryogenic compartment (A) receiving a cryogenic mass which is stored in a reservoir (4) slidably mounted in horizontal slideways (3) in the container, this reservoir being equipped with means for connection to a source of carbon dioxide in the liquid phase and means (26, 39) retaining the dry ice but allowing the gas to pass through, characterised in that the reservoir (4) of the cryogenic compartment (A) is carbon dioxide gas-tight and is internally divided, by the means (26, 39) retaining the dry ice and allowing the gas to pass through, into:

   a zone (C) for storing the dry ice, which communicates by means of a feed channel (27) with the means for connection to the source of carbon dioxide In the liquid phase,

   and a zone (D) for gas expansion, which communicates with a suction channel (29) which is made in the front wall (12) of the reservoir, spaced from the feed channel (27), and is equipped with means (30) for connection to a suction duct (31) for the carbon dioxide gas.
2. A container according to Claim 1, characterised in that the reservoir (4) is formed by the cryogenic compartment (A) as a whole and is delimited by the walls of the container and, on the one hand, a wall (10) which is horizontal and insulating, separating this compartment (A) from the conserving compartment (B), and whereof the respectively side and rear edges engage in respectively side (3) and rear (8) slideways of the container (2) to ensure support, insulation and gas-tightness and, on the other hand, a front vertical wall (12), which is insulating and integrally formed with the former wall, which fits into a front rebated portion (16) of the container and through which the feed channel (27) and the suction channel (29) pass, these two walls being monolithic and forming a removable drawer.
3. A container according to Claims 1 and 2 together, characterised in that the horizontal wall (10) forming the base of the reservoir (4) supports a metal gridded basket (17) which is lined on the inside by a sheet (19) permeable to gas but not to ice, is spaced from all the adjacent walls of the container and extends transversely only over part of the transverse dimension of the front wall (12) in the region of this wall through which the feed channel (27) passes, to form the gas expansion compartment (D) opposite the suction channel (29).
4. A container according to Claims 1 to 3 together, characterised in that the horizontal wall (10) is covered by a metal wall (11) and, in its part disposed below the basket (17), is equipped with an opening (21) which opens to the front and whereof the respectively side and rear inside edges are equipped with slideways for guiding and insulation which are intended to co-operate with complementary means provided on the respectively side and rear edges of a removable insulating panel (31).
5. A container according to Claim 2, characterised in that the reservoir is formed by a parallelepiped metal tray (32) which rests by means of its base on the horizontal insulating wall (10) and is equipped with a front opening (33) by means of which it is fitted into and fixed to the back of the front vertical wall (12), this wall (12), in an extension to the suction channel (29), bearing a blind sleeve (39) formed by a sheet which is permeable to gas but not to ice and which extends within the tray.
6. A container according to Claim 5, characterised in that the sleeve (39) is integrally formed with a collar (40) for fixing and connection to the suction duct (29), this collar being fitted into and detachably fixed in a shoulder-type housing, opening out from the front face of the front wall and communicating with the suction channel (29) through which the sleeve passes.
7. A container according to Claim 5, characterised in that the horizontal wall (10) has, below the tray (32), an opening (46) which opens to the front and whereof the respectively side and rear edges are equipped with slideways (47) for guiding and insulation which are intended to co-operate with complementary means provided on the respectively side and rear edges of a removable insulating panel (48).
8. A container according to any one of Claims 2 to 7, characterised in that the horizontal wall (10) is ringed by a gas-tight gasket (43) whereof the side and rear sections co-operate with the bases of the respectively side (3) and rear (8) slideways of the container (2) and whereof the front section, which projects from the vertical front wall (12), co-operates with the front door (9) of the container.
9. A container according to Claim 8, characterised in that the gasket (43) is formed by a tube which is inflatable by a pressurised fluid, by means of a valve (44) housed in a depression (45) which opens out in the front face of the front vertical wall (12).
10. A container according to any one of Claims 2 to 9, characterised in that the upper part (2a) of the container, laterally on each side and in its rear wall, has two slideways placed one above the other and intended to receive, in the case of the lower ones (3 and 8), the edges of the horizontal wall (10) of the drawer when it is in the position for conserving fresh produce and, in the case of the upper ones (3a, 8a), the same edges but with the drawer turned through 180° and with the tray (32) turned downwards.

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