EP0692086B1 - Chemical reactor, refrigerating machine and container provided therewith, and reagent cartridge therefor - Google Patents

Abstract

PCT No. PCT/FR94/00377 Sec. 371 Date Oct. 5, 1995 Sec. 102(e) Date Oct. 6, 1995 PCT Filed Apr. 5, 1994 PCT Pub. No. WO94/23253 PCT Pub. Date Oct. 13, 1994A reagent (26) combines exothermically with a cold refrigerating fluid exiting a refrigerating evaporator during a refrigeration cycle, then releases the refrigerating fluid endothermically once it has been heated to a sufficiently high temperature by means of a heating element (17) during a regeneration cycle during which the released refrigerating fluid condenses in a pressurized tank. The reagent is confined inside stainless steel walls (29, 31, 34) which prevent it from swelling. These walls include perforated tubes (34) lining channels (32) in which the mass exchanges take place during the combining and separating reactions. The heating element (17) is fitted in a central cavity (46). An air flow (54), which is interrupted during regeneration, evacuates the heat of the combining reaction by means of fins (56). The invention prevents the block of reagent from distorting and becoming progressively inoperative over repeated cycles.

Description

The present invention relates to a chemical reactor for refrigerating machine or the like.

The present invention also relates to a refrigeration machine thus equipped.

The present invention also relates to a container fitted with such a refrigerating machine.

The invention also relates to a cartridge for reagent.

We know the principle of refrigeration machines operating by chemical reaction.

From a refrigerant reserve at the liquid state under pressure, the fluid passes through a regulator then an evaporator placed in the enclosure to cool. Leaving the evaporator, the gas is sucked up by the reactor which contains a reagent which, at room temperature, is chemically hungry for this gas. The reagent chemically combines with the gas in producing some heat release.

When the supply of pressurized liquid is exhausted, the process stops and it is then necessary to initiate a regeneration process of supplying heat to the chemical reactor for the reagent to chemically separate from the gas refrigerant and expels this gas under high pressure. In leaving the reactor, the gas passes through a condenser then is collected in the liquid state in the Reserve. When the regeneration process is finished, the reserve is at its maximum level and a new refrigeration process can be initiated.

This known principle has so far posed serious implementation problems.

The reagent is subjected in service to constraints important, especially temperature and pressure, and it must also be able to absorb chemically and chemically separate from the fluid refrigeration with a speed corresponding to the flows refrigerant in the machine.

We know from US-A-2 649 700 a reactor chemical for refrigerating machine or the like comprising several elementary reagent blocks intended to absorb a chemical flux gaseous from an evaporator and desorb what flow by reverse chemical reaction under the effect of temperature rise. Blocks, of general shape annular, are confined between an inner wall and a peripheral wall. In addition, porous screens separate the elementary blocks from each other. They distribute the gas flow between surfaces upper and lower elementary blocks and a arrival and departure conduit. A channel parallel to the axis crosses the elementary blocks and the screens and serves as a collector for flows from screens or going towards them.

According to this document, the elementary blocks are in sintered metal and are therefore dimensionally stable, in particular with regard to the aforementioned constraints of temperature and pressure. The walls simply for the purpose of positioning the blocks.

Such an absorbent material has many cons: the amount of gas it is capable of to absorb per unit volume is relatively limited, and it retains absorbent particles poorly. This is what forces the gas flow to pass through screens that sort of serve as filter but which slow the flow and which risk moreover, in the long run, to take on particles seeking to flee the elementary blocks. In addition, the need to provide such screens further increases the already large volume that is required due to the relatively low absorption performance of blocks themselves. Finally, these blocks being metallic, preferably in stainless steel, the weight of the set is important.

We also know from US-A-2384460 a reactor in which the reagent is a powder likely to swell when absorbing gas refrigerator. This powder is housed in a body cylindrical while being confined in a determined volume. For mass transfers between the material absorbent and the gas pipe, the space reserved for material is traversed by perforated tubes filled with glass wool to prevent particles from leaking with the gas flow. So we find in a way a little different the peculiarity consisting of a filter supposed to retain particles and let the flow through gaseous. It will be understood, however, that the designer of this known device admits that the particles go cross the perforations of the tube. Otherwise, he would not have no glass wool in the tubes. By therefore there will be more and more particles in glass wool, then finally in the gas stream itself, that is to say precisely what we had wanted to avoid.

And we also know from EP-A-0206875 a solid reagent consisting of a mixture of chloride and of an expanded carbon derivative with structures in slats. This reagent solves transfer problems of mass and heat. It is able to absorb large quantities of gas per unit volume.

On the other hand, its mechanical strength is reduced and it has tendency to deform quickly under the action of pressure gradients and volume variations encountered during machine operation. In especially when the reagent absorbs gas by chemical combination, its volume tends to increase gradually. Following this, the separation chemical may be incomplete and the surfaces of the reagent planned for mass exchanges can be so distorted that they become ineffective. By example, if cavities have been provided in the block reactive to increase the exchange surface, these cavities have tendency to close after a few cycles refrigeration-regeneration.

FR-A-2 455 713 describes an absorbing device comprising a reactive body, possibly returned "practically self-supporting" by a binder. This body is locked up in a flexible envelope. We make an intimate contact of the envelope with the body by means of a difference of pressure between inside and outside of the envelope.

The object of the invention is thus to propose a reactor chemical for refrigeration machine or the like which is capable of ensuring good refrigeration performance which keep for many successive cycles, without prohibitive alteration of its original characteristics.

According to the invention, the chemical reactor for a machine refrigerator or the like, comprising a prefabricated block of reagent intended to absorb a chemical flux gaseous from an evaporator and desorb this flow by reverse chemical reaction due to an increase in temperature, the reagent block being confined between faces containment, at least some of which are permeable to mass exchanges, is characterized in that the block is subject to variation in volume depending on the quantity of absorbed gas, and in that the confining faces belong to containment walls capable of ensuring the shape stability of the block against the trend to said volume variations.

We have indeed noticed that the reagent, despite its tendency to increase in volume during the chemical reaction of combination with the refrigerant, supported without disadvantage of being confined in a substantially fixed volume. In particular, it turned out that this influenced negligible on its ability to chemically absorb a significant amount of refrigerant gas. On the contrary, the confinement stabilizes the physical structure of the block, which is favorable for obtaining good performance absorption and desorption.

Thus, according to the invention, the block of reactive in a substantially fixed volume and like this block is solid, it has good cohesion in service intrinsic thanks to which the active substance is well retained inside. We thus control the reagent leakage problems with single walls permeable, for example being walls openwork.

It is no longer necessary to pass the flow gaseous through more or less efficient filters to retain particles.

Thanks to the invention, for the first time, times a reliable reactor capable of storing in a limited volume of gas quantities allowing to consider the efficient production of cold using of an absorption device. For example, unlike absorption fridges that we know currently and which in fact are just coolers, an apparatus according to the invention is capable of producing ice by being placed under a high outdoor temperature (tropical type) without that its size and weight do not exceed usual standards.

The reactor according to the invention can receive the most if not all of the reagents containing chlorides.

The permeable walls can for example be formed by openwork tubes lining the channels parallels in the block.

During the combination reaction, it is important to dissipate the heat produced to prevent the reagent heats up and therefore becomes less hungry for gas.

For this, we can fix on a wall peripheral, belonging to the containment walls, cooling fins exposed to a flow cooling air, natural or forced.

On the contrary, during regeneration, it is advantageous that heat dissipation is also as low as possible. This is why the fins are placed in a defined annular chamber externally by an insulated sheath. During the refrigeration, this duct channels the air from cooling along the fins. During the regeneration, we at least partially isolate the space surrounded by the sheath relatively on the outside for prevent convection flow along the fins.

To heat the reagent during regeneration, preferably a heating element is used electrical resistance, mounted in a housing located at heart of the block so the heat produced by this element diffuses through the block practically without losses.

We can, if we wish, line this accommodation with a containment wall but it's also acceptable not to line the accommodation, accepting that the substance of the block, due to its tendency to inflate, enclose the heating element. The conduction between the heating element and the block will be that better. Of course, care must be taken to use a heating element whose temperature surface does not exceed acceptable limit temperature for the substance of the block.

With the heating element in the heart of the block and the fins on its periphery, the harmful trend of fins to play the role of thermal diffuser during regeneration is effectively combated.

According to its second aspect, the invention relates also a refrigeration machine comprising, in closed circuit, a high pressure tank, a regulator, evaporator and reactor according to the first aspect.

According to its third aspect, the invention relates in in addition to a container fitted with a refrigerating machine according to the second aspect.

According to a fourth aspect, the cartridge of reagent, especially to be part of a reactor according to the first aspect, of a refrigerating machine according to the second aspect or container depending on the third aspect, including a reagent block surrounded by a waterproof envelope, this block comprising cavities opening out through the sealed envelope, is characterized in that said cavities are closed tightly sealed by temporary fillings.

Such a cartridge allows handling and storage of the reagent without altering its properties especially without moisture absorption, since its manufacturing until its installation in the reactor.

Other features and advantages of the invention will emerge further from the description below, relating to nonlimiting examples.

• la figure 1 est un schéma de principe d'un conteneur frigorifique selon l'invention, pendant la réfrigération ;
• la figure 2 est une vue analogue à la figure 1 mais pendant la régénération ;
• la figure 3 est une vue en coupe axiale du réacteur des figures 1 et 2 ;
• la figure 4 est une vue en coupe transversale du réacteur des figures 1 et 2 ; et
• la figure 5 est une vue partielle d'une variante de réalisation.

In the accompanying drawings:

• Figure 1 is a block diagram of a refrigerated container according to the invention, during refrigeration;
• Figure 2 is a view similar to Figure 1 but during regeneration;
• Figure 3 is an axial sectional view of the reactor of Figures 1 and 2;
• Figure 4 is a cross-sectional view of the reactor of Figures 1 and 2; and
• Figure 5 is a partial view of an alternative embodiment.

In the example shown in Figure 1, the machine refrigerator 1 fitted to the refrigerated container 2 includes a refrigerant tank or tank liquid 3 subjected to its own vapor pressure saturating. The fluid is chosen in particular so that this pressure is relatively high. In the example, this fluid is ammonia whose pressure saturated steam is around 1.5 MPa at 20 ° C. An outlet orifice 4, provided at the bottom of the balloon 3 of so as to let out only liquid, is connected to a regulator 6 via a stop valve 7 which can be a solenoid valve powered by a rechargeable battery associated with container. The regulator 6 is located at the entrance of a evaporator 8, the outlet of which is connected by a fitting in T 10 on the one hand to a reactor 9 and on the other hand to a condenser 11. The condenser 11 is itself connected to an entrance 12 located at the top of the balloon 3.

The regulator 6 and the evaporator 8 are located at the interior of the insulated enclosure 5 of the container refrigerator 2 while the other elements described so far are located outside the enclosure 5. A non-return valve 13 prevents the fluid coming from of reactor 9 to flow towards the evaporator 8, while another non-return valve 14 prevents the fluid contained in balloon 3 to flow to the condenser 11.

A superheat measuring device 16, of the type known, controls the degree of opening of the regulator 6 of so that the fluid leaving the evaporator 8 is completely evaporated without being excessively overheated.

In a manner which will be described in more detail more far away, reactor 9 contains a reagent, preferably that known from EP-A-0477343 / WO-A-9115292 consisting of a mixture of chloride and a derivative expanded carbon with lamellar structures, having the property of chemically combining with the fluid refrigerator used, in this case ammonia, when its temperature is low, and to separate chemically ammonia when its temperature takes a predetermined high value.

This is why the reactor 9 has means selectively allowing it to be heated or cool. Ways to warm it up include basically a heating element 17 which is selectively activated by a switch 18. So not shown, the heating element can be thermostatically controlled. Means for cooling the reactor 9 include a battery-powered fan 19 rechargeable associated with the container. Fan 19 circulates a convection air flow inside an outer sheath 21 of the reactor. Sheath 21 is insulated to limit thermal leakage during heating, and has at its base a flap 22 that it is closed during heating to avoid the effect of fireplace. On the contrary, during the operation of the fan 19, the flap 22 is open.

We will now describe the general operation of the refrigeration machine shown in Figures 1 and 2.

When the machine is waiting to operate in refrigeration, the shut-off valve 7 is closed, so that the refrigerant reserve is trapped between the non-return valve 14 and the valve 7. Sa pressure is important since it corresponds to the saturated vapor pressure of ammonia at the outside temperature, for example 20 ° C.

To start a refrigeration cycle, simply open the shut-off valve 7 and the flap 22, and turn on fan 19. Liquid leaves balloon 3 via outlet 4 and valve 7, then passes through the regulator 6 losing pressure this which allows it to vaporize in the evaporator 8 in extracting heat from the container latent vaporization required. The gas thus formed crosswise through the check valve 13 then reached reactor 9 where given the low temperature maintained by fan 19, the gas chemically combines with the reagent. The effect when the reagent is substantially saturated with ammonia, balloon 3 is then at its low level.

You must then carry out a regeneration cycle, shown in Figure 2. To do this, we close the valve 7 and the flap 22, the operation of the fan 19 and the element is put into operation heating 17 using switch 18. It can also be expected to close the upper end of the sheath 21 by means, for example, of a shutter 23.

The heating of the reagent by element 17 causes separation of ammonia which leaves in gaseous state by the same conduit 24 as that by which it was entered the reactor. Given the temperature relatively high in the reactor, the pressure of the outgoing gas tends to be above temperature equilibrium in balloon 3 so the gas crosses the non-return valve 14. It is then brought to room temperature such as 20 ° C in the condenser 11 to reach the liquid state in the flask 3. When almost all of the reagent has been removed mobile ammonia (after commissioning, a certain amount of ammonia remains permanently prisoner of the block), the regeneration cycle stop. A new refrigeration cycle can to start. The ball 3 is then at its high level.

Such a container has the advantage of being able to undergo the regeneration process when in warehouse, then to be energy independent to ensure the refrigeration of the food in the container during transport of the container.

We will now describe in more detail the reactor 9 with reference to Figures 3 and 4.

The reagent block 26 has a general shape cylindrical having the same axis 27 as the sheath 21 and a diameter smaller than the inner diameter of the sheath 21.

In the example shown, block 26 is made up of a stack of elementary blocks 28 having the form pancakes.

According to the invention, the block 26 is enclosed in containment walls which are preferably made of stainless steel to be mechanically robust and resist corrosion.

The containment walls include particular a cylindrical casing 29 in which the elementary blocks 28 are fitted with a slight initial tightening. This tightening is intended to increase after use of the reactor due to the tendency of the reagent to be inflated as described above. The envelope 29 therefore has the role of shrinking the block 26.

The peripheral envelope 29 is closed each time axial end of block 26 by a closure plate 31 of circular shape. Block 26 is crossed by a number (four in the example) of channels 32 of cylindrical shape, which are parallel to the axis 27 and distributed angularly around it. Canals 32 coincide with lights 33 practiced through the plates 31 and thus open outside of the containment envelope of block 26. Channels 32 are lined with permeable containment walls made up of perforated stainless steel tubes 34. The perforations of the tubes 34 allow the mass exchanges between the gaseous medium of channels 32 and block 26 being exposed to this medium through the perforations. The annular ends of the tubes perforated 34 are joined with the periphery of corresponding lights 33.

In each of the two annular regions where the outer casing 29 is connected to one of the containment plates 31, the outer casing 29 is also tightly connected to a cap upper 36 and lower respectively 37. An upper spacer 38 and respectively lower 39 is mounted in position substantially central between each cap 36 or respectively 37 and the neighboring containment plate 31.

A distribution and collection chamber 41 is defined between the upper cap 36 and the plate containment 31 neighbor, and therefore communicates with the channels 32 through the lights 33. The upper spacer 38 has conduits 42 which communicate the collection and distribution chamber 41 with the inlet and outlet conduit 24 in the reactor 9, through a hole 43 in the cap upper 36 and an orifice 44 for entry and exit in the reactor. The lower cap 37 and the plate containment 31 corresponding define them a circulation chamber 50.

The heating element 17 is an electrical element in shape of rod whose useful length corresponds to the axial length of block 26, and which is mounted substantially free from play in an axial housing 46 provided at across the entire axial length of the block 26. The upper end of the housing 46 is closed by the plate 31 adjacent to chamber 41. According to a first embodiment shown on the left side of the Figure 3, the housing 46 is not lined so that in operation the reagent, taking into account its tendency to swell, encloses the heating element 17 with the advantage of improving thermal contact between them.

On the contrary, as shown on the right in Figure 3, if we fear that the temperature of the heating element 17 degrades the surrounding reagent, it is also possible to line the housing 46 with a tube 47. If this is waterproof, in particular non-perforated, it protects the heating element 17 corrosion.

The heating element is mounted through a hole 48 of the lower cap 37 and a central bore 49 of the lower spacer 39. This therefore serves as mounting for the heating element 17. It can by example be internally threaded to receive a corresponding threading of element 17 for its fixation. The lower containment plate 31 has a central light 51 for the passage of item 17.

To prevent ammonia from leaking out, the peripheral envelope 29 is waterproof, and it is tightly connected to the upper caps 36 and lower 37. These are also waterproof except for their respective holes 43 and 48, which communicate tightly with the passages interiors 42 and 49 of their respective spacer 38 and 39, as well as, in the case of the upper cap 36, with port 44 for connection to the rest of the circuit refrigerator. The heating element 17 is mounted tightly in bore 49.

The peripheral wall 29 and the sheath 21 define between them an annular chamber 52 intended for the upward circulation of cooling air flow produced by the fan 19 (not shown in the Figure 3) located below the cap lower 37. The assembly constituted by the block of reagent 26, the containment walls 29, 31, 32 and the caps 36 and 37 as well as the heating element 17 is supported inside the sheath 21 by any means suitable such as consoles 53 allowing the air flow passage 54.

The peripheral wall 29 carries fins 56 projecting into the annular chamber 52 in direction of the sheath 21. The fins 56 are arranged in axial planes so as to define between them air circulation corridors 57 (Figure 4) parallel to the axis 27. The fins 56 are for example made using profile sections T-shaped aluminum welded to the surface outside of the peripheral envelope 29.

At its upper end, the sheath 21 is closed by an openwork wall 58 whose openings 59 can be selectively closed by a shutter disc materializing the shutter 23 shown schematically in Figure 2.

• pendant le fonctionnement en réfrigération, l'ammoniac gazeux, froid et détendu, arrive par l'orifice 24 dans la chambre de répartition et collecte 41 puis dans les canaux 32 avant d'être absorbé par combinaison chimique avec le réactif 26 à travers les perforations des tubes de confinement 34. Le volet 22 est ouvert, comme représenté à la figure 1, et l'obturateur 23 est également dans la position d'ouverture, représentée à la figure 3. Le ventilateur 19 fonctionne et génère le flux d'air de refroidissement 54 lequel évacue la chaleur de la réaction de combinaison exothermique. Le flux 54 est accéléré par l'effet de cheminée à l'intérieur de la gaine 21, en raison de la température des ailettes 56, réchauffées par la chaleur de réaction.

The operation of reactor 9 is as follows:

• during the refrigeration operation, the gaseous ammonia, cold and relaxed, arrives through the orifice 24 in the distribution chamber and collects 41 then in the channels 32 before being absorbed by chemical combination with the reagent 26 through the perforations containment tubes 34. The shutter 22 is open, as shown in FIG. 1, and the shutter 23 is also in the open position, shown in FIG. 3. The fan 19 operates and generates the air flow cooling 54 which dissipates the heat of the exothermic combination reaction. The flow 54 is accelerated by the chimney effect inside the sheath 21, due to the temperature of the fins 56, heated by the heat of reaction.

During the regeneration, the operation of the fan 19, the shutter 22 is closed and the shutter 23 and we put into operation the heating element 17 for bringing the reagent to a temperature which can be of the order of 200 ° C. It results from an endothermic chemical reaction of separation between the reagent and the ammonia, which is evolves in a gaseous state through the perforations of the tubes 34 then through the inlet and outlet 44, via the distribution and collection chamber 41 and the conduits 42 of the spacer 38.

As at this stage the annular chamber 52 is isolated from the outside, the fins 56 no longer play any role of heat removal, so the reaction endothermic occurs with good efficiency.

The containment plates 31, although flat, effectively resist the tendency of the block to swell because they are adjacent to rooms 41 and 50 in which reigns the pressure of gaseous ammonia.

The resistance of the plates 31 is increased by the connection between them by the perforated tubes 34 and where appropriate the non-perforated tube 47, and also by spacers 38 and 39 which report the thrust of swelling on the caps 36 and 37 which are resistant thanks to their rounded shape. This reinforcement assured to plates 31 is useful when the pressure in rooms 41 and 50 are low while the trend the swelling of the block is maximum, for example at the end refrigeration cycle.

In the example in Figure 5, the blocks elementary 28 are prefabricated cartridges having their own outer casing 60 which is waterproof apart the openings 61 for the passage of the perforated tubes 34 and the heating element 17.

The envelope 60 has a simple sealing and mechanical cohesion, but is not designed to resist at operating pressure.

During the manufacture of the cartridges, the openings 61 with frangible shutters 62, waterproof, made for example of waterproof paper. When of the assembly, we first assemble the peripheral wall 29, the lower cap, the containment plate 31 lower, lower spacer 39, tubes perforated 34 and the heating element 17, then stacked the elementary blocks 28 in the peripheral wall 29 while the heating element 17 and the tubes 34 each perforate two shutters 62 of each block when it comes in and out of the bore respectively 63 or 64 which corresponds to it in the block. The bores 63 and 64 are not jacketed. The shutters 62 have for function to protect the block from unwanted moisture absorption before mounting.

The assembly of the reactor core ends with the fitting of plate 31 and cap 36 superior.

The embodiment according to FIG. 5 simplifies the assembly of the reactor by postponing a certain number of precautions, especially hygrometric, on the sole block manufacturing.

Of course, the invention is not limited to examples described and shown.

We could also perforate the plates 31 for increase the mass exchange surfaces.

To interrupt the flow of cooling air during regeneration, we could only close the top or bottom of the sheath.

There could be several spacers in each room, and several heating elements in the block.

The reactor could have two different accesses, one for the entry of ammonia during the refrigeration, the other for the ammonia outlet during regeneration.

Claims (28)

1. Chemical reactor for a refrigerating machine (1) or similar comprising a pre-made block of reagent (26) intended to absorb by chemical combination a gaseous flow coming from an evaporator (8) and to desorb this flow by reverse chemical reaction under the effect of a rise in temperature, the block of reagent (26) being confined between confining faces (29, 31, 34, 47) at least some of which (34) are permeable to mass exchanges, characterised in that the block (26) is capable of volume variations as a function of the quantity of gas which it has absorbed and in that the confining faces are part of confining walls capable of providing the block with shape stability in opposition to the tendency to the said volume variations.
2. Reactor according to Claim 1, characterized in that the permeable confining walls are perforated walls (34) interposed between the substance of the block and a space (32) for circulation of the gaseous flow.
3. Reactor according to Claim 1 or 2, characterized in that the permeable walls are tubes which line recesses (32) formed in the block (26).
4. Reactor according to Claim 3, characterized in that the recesses are channels (32) parallel with one another.
5. Reactor according to Claim 3 or 4, characterized in that, at one at least of their ends, the recesses open in a chamber (41, 50) adjacent to one of two opposite faces of the block (26) of reagent.
6. Reactor according to Claim 5, characterized in that in that the chamber (41, 50) is separated from the block by a confining plate (31), which is one of the confining walls of the block and through which the recesses (32) open.
7. Reactor according to Claim 6, characterized in that the chamber (41) adjacent to one of the ends of the block is connected with an orifice (44) for connection with a refrigeration circuit.
8. Reactor according to Claim 6, characterized in that at least one cross-piece (38, 39) extends between the confining plate (31) and an opposite wall (36, 37) also delimiting the chamber (41, 50).
9. Reactor according to Claim 8, characterized in that in the cross-piece (38) there is formed a passage (42) connecting the chamber (41) with a refrigeration circuit (24) .
10. Reactor according to Claim 8, characterized in that the cross-piece (39) is hollow and allows the passage and fixing of a heating element (17) engaged in a cavity (46) formed in the block of reagent (26) and opening through the confining plate (31) opposite the cross-piece (39).
11. Reactor according to Claim 4, characterized in that the channels (32) are distributed around a cavity (46) formed in a substantially central position in the block (26) and accomodating a heating element (17).
12. Reactor according to one of Claims 1 to 9, characterized in that the block (26) comprises a cavity (46) in which a heating element (17) is mounted.
13. Reactor according to Claim 12, characterized in that the heating element (17) is fitted substantially without play in the cavity (46), which is delimited by surfaces which are part of the block of reagent.
14. Reactor according to one of Claims 10 to 12, characterized in that the housing (46) is delimited by one of the confining walls (47).
15. Reactor according to Claim 6, characterized in that the confining plate (31) is connected by its periphery to a peripheral hooping casing (29) of the block, being one of the said confining walls.
16. Reactor according to Claim 15, characterized in that, in the region in which the confining plate (31) is connected to the peripheral casing (29), the confining walls are connected to the peripheral edge of an end cap (36, 37).
17. Reactor according to one of Claims 1 to 14, characterized in that the block (26) is of cylindrical shape and the confining walls comprise a peripheral hooping casing (29).
18. Reactor according to one of Claims 1 to 14, characterized in that the confining walls comprise a peripheral casing (29) carrying cooling fins (56) protruding into an annular chamber (52) contained between the peripheral casing (29) and an outer casing (21).
19. Reactor according to Claim 18, characterized in that the fins (56) are oriented in such a way as to define between them parallel air circulation channels (57), preferably vertical.
20. Reactor according to Claim 18 or 19, characterized by means (19, 22, 23) for selectively providing and preventing the circulation of air in the annular chamber (52).
21. Reactor according to one of Claims 18 to 20, characterized in that the outer casing (21) is heat-insulated.
22. Reactor according to one of Claims 18 to 21, characterized in that the confining walls (29, 31, 34, 47) are made of stainless steel and the fins (56) are made of aluminium.
23. Reactor according to one of Claims 18 to 22, characterized in that the fins (56) are formed from sections of profiled material fixed to the peripheral casing (29).
24. Reactor according to one of Claims 15 to 23, characterized in that the block (26) is fitted such that it is lightly clamped in the peripheral casing (29).
25. Reactor according to one of Claims 15 to 24, characterized in that the block (26) comprises elementary blocks (28) slipped one after the other into the peripheral wall (29).
26. Refrigerating machine comprising, in a closed circuit, a high pressure reservoir (3), a pressure reduction device (6) an evaporator (8) and a reactor (9) according to one of Claims 1 to 25.
27. Container provided with a refrigerating machine (1) according to Claim 26.
28. Reagent cartridge, in particular for being part of a reactor according to one of Claims 1 to 25, of a refrigerating machine according to Claim 26 or of a container according to Claim 27 and comprising a block of reagent enclosed in a fluid-tight casing (60), this block comprising cavities (63, 64) emerging through the fluid-tight casing (60), characterized in that said cavities (63, 64) are closed in a fluid-tight manner by temporary obturations (62).

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