EP0781394B1 - Device for the controlled transfer of cold from a cold source to a cooling enclosure - Google Patents

Description

The invention relates to a device for the regulated transfer of frigories between a cold store and a cold storage enclosure as defined in the preamble of claim 1. Such a device is known, for example, from document EP-A-0 166 086.

Although more specifically aimed at isothermal containers intended for the conservation of fresh or frozen products, during their transport and storage temporary, the device applies to any isolated enclosure in which the frigories ensuring the conservation comes from a reserve which can be constituted by an added box in the enclosure or on the enclosure, or by a separate compartment arranged above the enclosure.

The problem underlying the invention is that of temperature regulation. in the conservation enclosure, while the emission of frigories is permanent and uncontrollable, whatever the source, namely cartons containing frozen fluid, plate containing eutectic liquid, brine, or dry ice in the form of snow, sorbet, or bread.

This lack of regulation leads to two drawbacks which limit the application of this method of conservation.

The first is that of the consumption of frigories which, depending on the outside temperature, the overall insulation coefficient of the container, and the duration of the transport and / or storage, is highly variable and leads to overconsumption, when all the energy is not consumed, since it is planned in a quantity greater than the real needs. or deterioration of the foodstuffs, or of the products to be preserved, when the quantity supplied is insufficient for the shelf life.

The second drawback is encountered more particularly in the use of the dry ice which, due to its temperature of the order of - 70 ° to -80 ° C, can manage, despite the presence of protective screens, to freeze, burn or dehydrate food perishable.

These drawbacks are well known, but despite the many solutions proposed in the state of the art, they have not yet been able to be entirely eliminated, by reliable means regulating the temperature in the conservation enclosure.

Thus, for example, EP - A 136 458 and EP - A 166 086, describe devices distribution of frigories between a reserve and an enclosure using networks thermal tubes, also called heat pipes, composed of closed tubes containing, under vacuum, a heat transfer fluid removing the frigories from the reserve to bring them into the enclosure.

Due to the absence of any regulation and the operating principle of heat pipes, frigories try to accumulate on the arm of the conservation enclosure by emptying the reserve, which neither solves the problem of consumption, nor that of obtaining a optimal temperature, favorable for the good conservation of foodstuffs.

The object of the present invention is to remedy these drawbacks by providing a device for the regulated transfer of frigories between a reserve and a conservation enclosure, device for regulating the temperature in the enclosure, regardless of the power of the refrigerant installed in the reserve, while considerably reducing the consumption of this means.

This object is achieved by a device as defined in claim 1.

In this device, of the type using a heat pipe, the heat pipe is composed by an exchange and regulation plate placed in the enclosure, below the reserve and near but without contact with the insulating wall separating the reserve and the enclosure, this plate, provided with an internal serpentine network for the heat transfer fluid and, on one side, at least one sensor tube communicating with the aforementioned network and penetrating into the reserve of frigories by a channel of the insulating wall, being mounted oscillating around a horizontal transverse axis between two positions, arranged on either side of the plane horizontal, i.e. an exchange position in which it is tilted up and down in starting from the sensor tube, and a stabilization position in which it is inclined from below at the top from this sensor tube, said plate also being connected by its side opposite to that with the sensor tube, to motor means controlling its oscillation by on either side of the horizontal plane as a function of the temperature in the enclosure.

In this device, when the heat pipe, consisting of the exchange plate and the sensor tube is in the exchange position, i.e. when the plate is tilted from top to the bottom from the sensor tube, the end of this sensor tube is inside the reserve of frigories, of which it can capture the frigories to transmit them to the coil contained in the exchange plate.

As soon as the temperature in the enclosure reaches a defined threshold, for example 4 °, 0 ° or 20 ° C, the drive means cause the plate to tilt so that, part, the latter coming in the stabilization position, either inclined from the bottom upwards starting of the sensor tube and that the end of the sensor tube is no longer in the reserve. but in the wall separating this reserve from the conservation enclosure. The sensor tube is no longer in the reserve of frigories and the plate no longer having the adequate inclination, the cold can no longer be taken to the conservation area.

It is obvious that a rise in temperature in the enclosure triggers the operation of the motor means to bring the plate from its stabilization position to its exchange position.

In one embodiment of the invention, the sensor tube, rigid and integral with the plate, has at its free end a suitable insulating plug, when the plate is in stabilization position, to close the communication channel between the reserve and the enclosure of conservation to interrupt any heat exchange with the reserve.

This simple arrangement prevents any loss of calories by conductivity thermal through the material constituting the heat pipe.

In another embodiment, the sensor tube consists of a body tubular, elastically deformable longitudinally, sealingly passing through the channel of the insulating wall, the end of which, arranged in the reserve, is connected to the heat transfer fluid network of a transfer plate which, similar to the exchange plate and regulation with which it forms a single heat pipe, is arranged on the bottom of the reserve, in a fixed manner and is inclined from the top downwards towards the sensor tube.

This transfer plate, which is therefore permanently placed in the reserve of frigories, reduces the response time of the heat pipe when the exchange plate and regulation is brought to the exchange position but does not influence the emission of frigories when the exchange plate is in the stabilization position, since precisely the circulation of the heat transfer fluid within the heat pipe is interrupted by the reversal of the angular position of the exchange plate.

It already appears that the device according to the invention brings significant progress to the control of the temperature regulation in the conservation enclosure, while allowing, with the same refrigerant mass to save the emission of frigories and to increase the autonomy, therefore to increase the shelf life.

Figures 1 et 2 sont des vues partielles de côté en coupe montrant une première forme d'exécution de ce dispositif, respectivement lorsqu'il est en position de stabilisation, et en position d'échange,

Figure 3 est une vue en plan par dessus de la plaque d'échange,

Figure 4 est une vue de côté en coupe transversale et à échelle réduite d'un conteneur équipé du dispositif selon l'invention,

Figures 5 et 6 sont des vues partielles de côté en élévation montrant une autre forme d'exécution du dispositif lorsque la plaque d'échange est, respectivement, en position de stabilisation et en position d'échange, et dans le cadre de l'application de ce dispositif à une réserve de frigories alimentable par un fluide frigorigène ou par des pains de glace carbonique, et par un fluide frigorigène refroidi par serpentin,

Figure 7 est une vue partielle de côté, en coupe transversale, montrant l'application du dispositif à un conteneur équipé d'une réserve hermétique à refroidissement par une platine extérieure,

Figure 8 est une vue partielle de côté en élévation et en coupe transversale montrant le conteneur de figure 7, lorsque sa réserve est encastrée sur une platine d'alimentation,

Figure 9 est une vue partielle de côté en élévation avec coupe transversale montrant l'application du dispositif à un conteneur avec réserve de frigories rechargeable par un dispositif de régénération extérieur.

Other advantages will emerge from the description which follows with reference to the appended schematic drawing representing, by way of example, several embodiments of this device in the case of its application to a container.

FIGS. 1 and 2 are partial side views in section showing a first embodiment of this device, respectively when it is in the stabilization position, and in the exchange position,

FIG. 3 is a plan view from above of the exchange plate,

FIG. 4 is a side view in cross section and on a reduced scale of a container equipped with the device according to the invention,

Figures 5 and 6 are partial side views in elevation showing another embodiment of the device when the exchange plate is, respectively, in the stabilization position and in the exchange position, and in the context of the application from this device to a reserve of frigories which can be supplied by a refrigerant or by dry ice bars, and by a refrigerant cooled by a coil,

FIG. 7 is a partial side view, in cross section, showing the application of the device to a container equipped with an airtight reserve cooled by an external plate,

FIG. 8 is a partial side view in elevation and in cross section showing the container of FIG. 7, when its reserve is embedded on a supply plate,

Figure 9 is a partial side view in elevation with cross section showing the application of the device to a container with reserve of refrigerants refillable by an external regeneration device.

In the embodiment shown in Figures 1 to 4, the reference numeral 1 designates the container with its reserve 2 of frigories. These two elements have insulating walls 3 and are therefore separated by a wall 3a. The conservation enclosure 10, formed in the container 1, communicates with the cold store 3 via a channel 4.

The regulation device according to the invention is composed of a plate 7, of transfer and exchange, containing a meandering network 6, shown here by a serpentine. This network, filled with heat transfer fluid after being emptied of air, is part of the heat pipe also comprising at least one sensor tube 5 projecting vertically upwards from the plate 7.

The plate 7, which is made of heat conductive material, and by example in metal such as stainless steel or aluminum, is arranged in the enclosure, below and close, but without contact, to the wall 3a separating the enclosure 10 from the reserve 2.

Figure 3 shows that this plate has, plan view from above, a shape general rectangular, whose dimensions are smaller than those of the section transverse of the enclosure 10 in which the plate is called to move. Indeed, this plate is mounted oscillating around a horizontal transverse axis, materialized by the two tenons 12, visible in FIG. 3. It can oscillate on either side of the horizontal plane between an exchange position, represented at A in FIG. 2, and a stabilization position, shown in B in Figure 1.

The sensor tube 5 extends the heat transfer coil and is provided at its end free, which enters the reserve of frigories 2, of a plug 8 of insulating material of which the usefulness will be specified later.

By its edge, which is opposite to that equipped with the sensor tube 5, the plate 7 is connected to motor means which, in the embodiment of Figures 1 to 4, include an electric motor 11 powered by batteries 22 actuating an endless screw 23. This screw endless cooperates with a nut, not shown, linked to the plate. Motor power 11 is under the control of a thermostat 9, placed in the enclosure of conservation 10.

The cold store 2 is provided with a hatch 13 enabling it to be filled with refrigeration products which may consist of glycol 19 or ice packs carbon dioxide 20. This reserve also has a valve 14 used for degassing the gaseous products and a sheet metal 15 protecting the sensor tube, so that its movement does not is not hindered by any product or refrigerant. Finally, a trap door 16 is used for exchanging the batteries 22 and for controlling the motor 11, which can moreover be replaced by an electromagnet.

In FIG. 1, the plate 7 is in the stabilization position and therefore inclined from the bottom at the top from the sensor tube. In this position, it opposes the circulation of frigories in the coil 6 of the heat pipe and therefore interrupts any emission of frigories in direction of the conservation area. It will be noted that, in this position, the plug 8 of the sensor tube 5 seals the end of the communication conduit 4 between the reserve 2 and the enclosure 10 and thus avoids any heat exchange by direct conduction. When the temperature in the enclosure rises, the thermostat 9 triggers the supply of the motor 11 which, by screw 21, swings the plate from its stabilization position B to its exchange position A in which it is inclined up and down starting from the sensor tube 5. This has the effect, on the one hand, of penetrating the upper end of the sensor tube 5 in reserve 2, and on the other hand, to bring the heat pipe into its operating position. he as a result that the frigories, taken by the sensor tube 5 and circulating in the coil 6, are transferred to the plate 7 which diffuses them into the enclosure 10.

It is very important that, in its exchange position, the plate 7 has a inclination which with respect to the horizontal plane is at least of the order of 3 °, in order to allow the operation of the heat pipe. The inclination of the exchange plate, in its stabilization position, is of the same order, but may be lower, the main thing being that the plate passes beyond the horizontal position to stop the operation of the heat pipe.

Of course, as soon as the temperature in the enclosure 10 is sufficiently lowered and reaches the trigger threshold of thermostat 9, it controls power to the motor 11 to bring the plate into its stabilization position.

It appears from the above that the temperature regulation in the enclosure is done according to the all or nothing principle, and automatically. This allows to reduce the consumption of refrigerated products and increase the duration of consumption compared to current containers not containing such a device.

Figure 4 shows a complete and equipped transport container. His enclosure 10 is equipped with shelves 18 and a grid 17 protecting the plate and preventing its travel space is congested with products or foodstuffs stored in the enclosure.

In the embodiment shown in Figures 5 to 9, the sensor tube 5a is constituted by a tubular body deformable longitudinally in an elastic manner and, by example, originally having folding zones facilitating its longitudinal deformation. As before, this sensor tube communicates by its lower end with the network 6 of plate 7, but in addition, it communicates by its upper end with a coil 26 circulating in a transfer plate 27, arranged on the bottom of the reserve 2 of frigories. The plate 27 occupies a fixed position and is inclined relative to horizontally, from top to bottom, going towards the sensor tube 5a. Network 26, network 6 and intermediate sensor tube 5a define the same heat pipe.

In this embodiment, the transfer plate 27, in direct contact with refrigerants 19 or 20, supplies plate 7 more quickly with refrigerants when it passes into the exchange position, shown in FIG. 6. It will be noted that in this plate exchange position 7, the tube 5a is compressed longitudinally, without this affects the circulation of the heat transfer fluid which flows through it between the transfer plate 27 and the exchange plate 7 and vice versa.

The tilting of the plate 7 can be ensured by the same motor means than those described in the previous embodiment or by those described in Figures 5 and 6. These means are essentially composed of a bar 28 made of a good conductive material heat constituting, at the same time, means for detecting the temperature in the enclosure 10 and motor means.

In the embodiment shown in Figures 5 and 6, this bar is arranged vertically against one of the vertical walls of the enclosure 10 with respect to which it is guided in longitudinal translation. It rests on the lower wall of the enclosure and is provided at its upper end with a head 29 supported with interposition of a spring 30 against the free end of the plate 7. It is easy to see that the variations in temperature in the enclosure 10 cause variations in the length of the bar 8 and, in consequence, variations in the angular position of the plate 7 relative to the plane horizontal. The spring 30 makes it possible to absorb the large elongations of the bar 28, by example, in the case of very hot weather, by avoiding that the bar destroys the plate 7 and the regulating device.

In the embodiment shown in Figures 7 to 9, the bar 28a is arranged horizontally in sliding bearings, not shown, below the plate 7 in the gap between plate 7 and the protective grid 17. One of its ends is fixed against the vertical wall of the container arranged on the side of the sensor tube 5a and its other end is in abutment against a lever 31 actuating a finger 32 projecting towards the bottom of plate 7.

The bar can be made of metal, but it can also be made of synthetic material and, for example, in a polyethylene having a good coefficient of expansion such as high density polyethylene having a coefficient of expansion of the order 0.004.

These drive means are particularly advantageous since they do not require no energy, are reliable, are space saving and can work equally well for storage at 4 ° C or 0 ° C for fresh products, or - 25 ° C for frozen products, and this by simple modification of the position of their anchoring relative to the container.

The regulating device according to the invention can be used whatever the nature the products or means constituting the reserve of frigories. This is how, as shown in Figure 6, the reserve 2a can be arranged to receive a liquid 35, is freezing at a temperature below the storage temperature in the enclosure, and include, for this purpose, a conduit 36 for supplying the liquid reserve and a conduit 37 for draining this liquid, but also a cooling coil 38 for this liquid. The two ends 38a and 38b of the coil respectively pass through one of the insulating walls 3 of the reserve 2 and are provided with fittings 39a. 39b can be connected to a refrigeration unit supplying a refrigerant at a temperature lower than that liquid 35 contained in the reserve.

Figure 9 shows the regeneration of the cold store 2 using a device 40 comprising a refrigeration unit 42 whose coil 43 ensures the cooling of a refrigerant 44, placed in an insulating container 45. Two flexible conduits 46a and 46b, of which that 46a is provided with a pump 47, lead to fittings 48a, 48b which can be connected to the fittings 39a, 39b of the coil 38 of the reserve calories from the container. The regeneration of reserve 2a is carried out by making circulate the refrigerant 44 towards this reserve. Trailing the coil 38, this liquid causes the fluid 35 to freeze. As soon as this is reached, the fittings 48a and 48b are disconnected and the container can be used to receive the products from which it conservation must be ensured.

It will be noted that, under these conditions, the exchange plate 27, by its large contact surface with the frozen product, promotes the transmission of frigories to the heat pipe. When all the frigories are consumed, and in anticipation of a new one use, the container is returned to loading station 40. This may be of the type that which, described in European Patent No. 639,256 in the name of the applicant, takes the fluid having lost their frigories by the circuit 39b, 48b, 46d, to direct it towards a first reserve then replaces it with a refrigerated fluid coming from another reserve by the circuit 46a, 48a, 39a.

With this arrangement, the container has a large reserve of frigories, without being equipped with a refrigeration unit.

For example, to obtain in a conservation enclosure 10 having a capacity of 900 liters, a storage temperature of the order of - 20 to - 25 ° C, the fluid refrigerant 35 placed in the reserve 2a is brought to a freezing temperature of the order of - 30 to - 33 ° C by the coil 38 whose fluid 44 is itself brought to a temperature of the order of -37 ° C. Such a refrigeration charge allows, even in summer conditions, to ensure the conservation of frozen products for a period of several days, thanks to the regulating device according to the invention.

In the embodiment shown in Figures 7 and 8, the reserve 2b can also be adapted to be recharged in calories by the device described in the patent French 2,689,222 in the name of the applicant. For this purpose, the reserve 2b includes a cavity watertight opening to the outside and capable of being closed by a hatch 52. The wall of this cavity is made of heat conductive material and is in direct contact with the liquid refrigerant 53 placed in the reserve.

The frigories are loaded by introducing into the cavity 50 a plate 54 internally traversed by the evaporator 55 of a refrigeration unit 56. After that the refrigerant 53 has been brought to the appropriate temperature, up to its freezing, the plate 54 carried by a bracket 57 is uncoupled from the container 1, and the hatch 52 is closed.

This charging technique also makes it possible to regenerate the reserve of frigories at a fixed station, without the need to equip the container with a refrigeration unit.

In this application, the regulation device is very important because it saves the dissipation of frigories and increases the shelf life of products and commodities arranged in the container.

In FIG. 8, the references 58, 59 and 60 designate a cowling and flaps insulators folded down onto the plate 55 to avoid heat loss from the plate 58 when not in use.

Although very interesting in the case of its application to the regulation of temperature in the storage container, the regulated transfer device according to the invention can also be applied to any container having insulated walls and intended to contain any products. It can, for example, be arranged in a case placed on an insulating box of the type used to contain fresh fish, or any other fishery product immersed in a bed of crushed ice, or for the transfer of corpses.

Claims (9)

1. A device for the controlled transfer of negative thermal energy between a negative thermal energy store (2,2a,2b) and a cold storage enclosure (10) in which the transfer of negative thermal energy between the upper store (2,2a,2b) and the lower enclosure (10) separated by an insulating wall (3a), is effected by a thermal tube or heat duct made of material which is a good heat conductor and containing, under vacuum, a heat-exchanging fluid, characterised in that the heat duct comprises an exchange and control plate (7) disposed in the enclosure (10), below the store (2,2a,2b) and close to but not in contact with the insulating wall (3a) separating the store and the enclosure, this plate (7) being provided with a winding internal system (6) for the heat-exchanging fluid and, on one side, with at least one collector tube (5,5a) communicating with the aforementioned system and penetrating into the negative thermal energy store (2,2a,2b) through a passage (4) formed in the insulating wall (3a) and being mounted so as to oscillate about a transverse horizontal axis between two positions disposed to either side of the horizontal plane, namely an exchange position (A), in which it is downwardly inclined from the collector tube, and a stabilisation position (B), in which it is upwardly inclined from the collector tube (5,5a), the plate (7) also being connected, by its side opposed to that having the collector tube (5,5a), to motor means (11 and 9,28,28a) controlling its oscillation to either side of the horizontal plane as a function of the temperature within the enclosure (10).
2. A device according to claim 1, characterised in that the exchange and control plate (7) forms, with respect to the horizontal, and when it is in the exchange position (A), an angle of at least 3°.
3. A device according to any one of claims 1 and 2, characterised in that the collector tube (5), which is rigid and joined to the plate (7), has at its free end an insulating plug (8) adapted, when the plate is in the stabilisation position (B), to close the communication passage (4) between the store (2) and the storage enclosure (10) in order to cut off any heat exchange with the store.
4. A device according to any one of claims 1 and 2, characterised in that the collector tube (5a) is constituted by a resiliently longitudinally deformable tubular body, extending in sealed manner through the passage (4) in the insulating wall, and of which the end located in the store is connected to the heat-exchanging fluid system (26) of a transfer plate (27) which, similar to the exchange and control plate (7) with which it forms a single heat duct, is disposed on the base of the store (2,2a,2b), in a fixed manner, and is downwardly inclined towards the collector tube (5a).
5. A device according to any one of claims 1 to 4, characterised in that the motor means are constituted by an electro-magnet supplied by batteries (22) and of which the supply is controlled by a thermostat (9) disposed within the storage enclosure (10).
6. A device according to any one of claims 1 to 4, characterised in that the motor means are constituted by an electric motor (11) connected to an endless screw (21) cooperating with a nut joined to the plate (7), this motor being supplied by batteries (22) under the control of a thermostat (9) disposed in the storage enclosure (10).
7. A device according to any one of claims 1 to 4, characterised in that the motor means are constituted by a bar (28,28a) of heat conducting material having a high coefficient of expansion, of which one end is fixed against one of the walls of the enclosure (10), and of which the other end comes into contact with the plate (7), directly or by means of an angle-change drive.
8. A device according to claim 7, characterised in that the bar (28a) is disposed horizontally below the exchange plate (7), between this plate and a protective grill, and its free end comes to bear against a lever (31) actuating a finger (32) projecting vertically towards the bottom of the plate (7).
9. A device according to any one of claims 1 to 8, characterised in that the negative thermal energy store (2a) contains a fluid (35) which freezes at a temperature lower than the storage temperature in the enclosure (10), and a freezing coil (38), the two ends (38a,38b) of this coil passing through one of the insulating walls of the store (2a), being provided with connections (39a,39b) for connection to the inlet (46a) and outlet (46b) conduits of a cooling unit (40) ensuring the cooling of the refrigerant fluid (44) contained in the coil (38) to a temperature lower than the freezing temperature of the fluid (35) contained in the store (2a).

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