EP1746365A2 - Sorption cooling element with gasproof film - Google Patents

Abstract

The unit has a sorbent material (4) sealed into a sorbent-containing pouch (1) having a multilayer sheeting material with metallic layer or metallized layer. The material allows a vacuo to sorb a vaporous working medium that evaporates from a fluid working medium in an evaporator. A shut-off unit prevents the working medium vapor from flowing into the sorbent material upto the moment at which the cooling process is initiated. An independent claim is also included for a method for producing a cooling unit.

Description

The invention relates to a sorption cooling element for cooling with a gas-tight film in which is produced by evaporation of a working fluid and subsequent sorption of the working medium vapor in a sorbent under vacuum cold and method for producing and starting these cooling elements.

A sorption d are apparatuses in which a solid adsorbent, a second, boiling at lower temperatures means the working fluid, as vapor while releasing heat sorbed (sorption phase). The working fluid evaporates in an evaporator while absorbing heat. After the sorbent is saturated, it can be desorbed by supplying heat at a higher temperature (desorption phase). During this process, working fluid evaporates from the adsorbent. The working fluid vapor can be reliquefied and then re-vaporized, etc.
A sorption b are apparatuses in which a liquid absorbent is employed. The generic term sorption both A and A d sorption b sorption systems are classified.

Adsorption apparatus for cooling with solid sorbents are from EP 0 368 111 and the DE-OS 34 25 419 known. Sorbent container, filled with sorbents, thereby absorb working agent vapor, which is produced in an evaporator, and sorb it under heat release. This Sorptionswänne must be removed from the sorbent. The chillers can be used to cool and keep food warm in thermally insulated boxes.

The WO 01/10738 A1 describes a self-cooling beverage can with an evaporator inside and a sorber outside the can. The cooling is started by opening a steam channel between evaporator and sorber. The cold generated in the evaporator is discharged through the surfaces of the drink to be cooled within the can. The heat generated in the sorbent is stored in a heat buffer. The self-cooling beverage can is heavily modified over an ordinary can and expensive to manufacture.

Further theoretical refinements of self-cooling containers are in the WO 99/37958 A1 compiled. Cost effective is none of the devices implement and manufacture.

The US 6,474,100 B1 finally describes a self-cooling cooling element the outside of a bag for liquids or bulk materials. The sorbent is enclosed in a flexible, multi-layered film. The contact with the hot sorption filling is reduced to a minimum by insulation and flow materials as well as by heat storage masses lying between them. The temperature compensation between the hot sorber filling and the cold evaporator, which are opposed over a large area, must be reduced by an elaborate insulation.

The object of the invention are inexpensive sorption cooling elements for cooling, as well as processes for their preparation.

These objects are achieved by the characterizing features of claims 1 and 14. The dependent claims show other inventive devices and methods.

Sorbents can reach temperatures of over 100 ° C during the sorption process. For such high temperatures, the multi-layer films used in the packaging sector are not suitable. In particular, the polyethylene layers used for the sealing soften even at 80 ° C and leave the sheath to leak under vacuum. A welding layer of polypropylene, however, can withstand much higher temperatures. Its melting point is above 150 ° C.
In combination with high temperatures, sharp edges, corners and tips of sorbent granules create impermissible leaks. This risk is counteracted by at least one polyester layer within the multilayer film according to the invention. Polyester films are particularly tear and puncture resistant. The actual gas barrier is ensured by a layer of a thin metal foil or a metallized layer. Thin aluminum foils with a layer thickness of approx. 8 μm have proven to be suitable for this purpose. Less dense are metallized plastic films. Nevertheless, with short storage periods, the use of these metallized films is possible, especially since they are cheaper to produce compared to the metal foils.
The individual layers of a multilayer film are connected to one another by means of adhesive layers. Commercially available adhesives contain solvents which are not completely removed from the adhesive layer during bonding. Over longer periods of time, these solvents then diffuse through the internal layers, particularly the polyethylene layer, and affect the vacuum within the cooling element. The diffusion is enhanced at higher temperatures, such as occur in the sorption and manufacturing process of the cooling elements. The adhesive used must therefore also be designed for high temperatures.
According to the invention are multi-layer films having a polyester layer thickness of 12 to 50 microns, an aluminum layer thickness of 6 to 12 microns and a polypropylene layer thickness from 50 to 100 microns for use. Use find such films z. As for the packaging of foods that are sterilized after packaging for preserving at temperatures above 120 ° C.

Even more stable multilayer films are obtained when a further approximately 15 microns thick polyester layer is bonded between the aluminum and the polypropylene layer. Sharp or pointed Sorptionsmittelteile then can not penetrate to the gas barrier, the aluminum layer.
Inventive multilayer films are z. B. on the company Wipf AG in Volketswil, Switzerland. When using such films cooling elements with a leakage rate of less than 1x10 high -7 mbarl / sec are possible. Shelf life thus reaches several years without the cooling readiness being restricted.

The welding (sealing) of multilayer films to bags and the filling of bulk material and the subsequent evacuation are state of the art in the food industry.
Countless bag sizes and shapes are in use there. Particularly noteworthy are stand-up pouches, pouches with pouring openings, pouches with cardboard reinforcement, tear-open pouches, peel-effect pouches for easier opening and pouches with valves. All of them can be advantageous with their specific properties for the cooling elements according to the invention.

When filling solid sorbent in bags, dust forms, which deposits on the inside of the film. Dust on the subsequent sealing sites can lead to leaks if the dust layer is too thick compared to the polypropylene layer. Polypropylene layer thicknesses of 50 to 100 microns are sufficient to melt fine dust grains in the polypropylene layer safely and vacuum-tight.

When using films according to the invention, it is possible to wrap hot, sharp-edged and dust-releasing sorbent without further protective liners directly under vacuum and to store over a period of several years without foreign gases entering the cooling element from the film material itself or through it Impair sorption or even completely stop.

The sorbent used is advantageously zeolite. In its regular crystal structure, this can reversibly absorb up to 36% by mass of water. In the application according to the invention, the technically feasible water absorption is 20 to 25%. Zeolites still have a considerable water vapor sorption capacity even at relatively high temperatures (above 100 ° C.) and are therefore particularly suitable for the use according to the invention.
Zeolite is a crystalline mineral that contains silicon and aluminum oxides in a framework structure contains. This very regular framework structure contains cavities in which water molecules can be sorbed by releasing heat. Within the framework structure, the water molecules are exposed to strong field forces whose strength depends on the amount of water already contained in the framework structure and the temperature of the zeolite.
Naturally occurring natural zeolite types absorb significantly less water. Per 100 g of natural zeolite, only 7 to 11 g of water are sorbed. This reduced water absorption capacity is due on the one hand to their specific crystal structures and on the other hand to non-active impurities of the natural product. For cooling elements, which also have the opportunity during a longer cooling period to release the heat of sorption via the shell, synthetic zeolites with their greater sorption capacity are therefore to be preferred. For cooling elements with high cooling capacity and / or short cooling time, in which the sorbent remains relatively hot, according to the invention also natural zeolites are used. At high sorbent temperatures, synthetic zeolites are no longer at an advantage over the natural ones. Typically, with inhibited release of the heat of sorption and concomitant high sorbent temperatures of over 100 ° C, both types can sorb only 4 to 5 g of water vapor per 100 g of dry sorbent mass. Economically, even the natural representatives are clearly in the advantage for this application, since the price is considerably lower.
Natural zeolites have another advantage. The non-active admixtures are typically 10 to 30%. They are not actively involved in refrigeration, but they are heated by the neighboring zeolite crystals. They thus act as an additionally installed, inexpensive heat buffer. The result is that the zeolite filling is less hot and thus can sorb additional water vapor at lower temperatures.

Natural zeolite granules consist of broken or crushed fragments and therefore have sharp and pointed geometric shapes that can puncture or cut through the envelope under vacuum and elevated temperatures.

Another disadvantage of natural, but also synthetically produced zeolites is that they contain, depending on occurrence and degradation processes admixtures that give off in a vacuum and especially at higher temperatures gaseous components that adversely affect the cooling process.
This problem of gas release is solved by heating natural zeolites to at least the later sorbent temperature before production of the cooling element and placing them under vacuum. In this procedure, zeolites can release their interfering constituents according to the invention. This thermal treatment is particularly efficient if at the same time the presorbed water can be evaporated off. To increase this treatment at To be able to carry out temperatures and to withstand the sharp edges and tips, gas-tight multilayer films having an inner polypropylene layer and at least one polyester layer are used according to the invention.

Among the approximately 30 different natural zeolites, the following are to be used advantageously for the cooling elements according to the invention: clinoptilolites, chabazites, mordenites and phillipsites.

Naturally occurring substances can also be returned to nature without environmental requirements. Natural zeolites can after their use in cooling elements z. B. be used as soil conditioner, as a liquid binder or to improve the quality of water in stagnant water.

Of the synthetic zeolite types, the types A, X and Y, each in their inexpensive Na form are recommended.

In addition to the combination of zeolite / water, other solid sorption pairings are also possible for use in cooling elements according to the invention. Particularly noteworthy are bentonites and salts, which also represent suitable combinations with the working medium water. Activated carbon can also offer a beneficial solution in combination with alcohols. Since these pairings also work under reduced pressure, they can be welded into multi-layer films according to the invention.

According to the invention, the amount of sorbent is to be dimensioned and arranged so that only a minimal pressure drop within the sorbent must be overcome for the incoming water vapor. The pressure drop should be less than 5 mbar, in particular for water as working fluid. In addition, the sorbent must provide the inflowing agent vapor sufficient surface for attachment. In order to ensure a uniform sorption within the sorbent and a low pressure drop, particularly sorbent granules have been proven. Granule diameters between 3 and 10 mm show the best results. These are easy to pack in foil bags. After evacuation, they form a hard, pressure and dimensionally stable sorption container, which retains the forced upon evacuation form. However, preformed stable, dimensionally stable zeolite blocks, into which the flow channels can already be incorporated and whose shape is adapted to the desired cooling element geometry, are also advantageous. The stable zeolite blocks may have cavities in the region of the later steam opening, which can facilitate the cutting of the film by means of a cutting tool and can pick up the separated film piece, so as not to obstruct the flow through the steam channel.

The sorption heat releases heat of sorption that heats the sorbent. The absorption capacity for water decreases sharply at higher sorbent temperatures. In order to maintain a high cooling capacity over a longer period, it makes sense to cool the sorbent.
In direct contact of the sorbent with the multi-layer film resulting heat of sorption can be dissipated unhindered through the film to the outside. As a rule, the heat will be dissipated to the surrounding air. It is also very efficient to cool the sorption container by means of liquids, in particular with water.

Since the heat transfer to an air flow from the outside of the sorbent bag is of the same order of magnitude as the heat transfer of a sorbent granulate to the inside of the bag, in principle large film surfaces without ribbing, such as cylinder, plate or tube geometries, are recommended. In particular, since zeolite granules have a low heat conduction, the sorption containers are to be designed so that the average heat conduction within the sorbent does not exceed 5 cm.

• A: Schnelle Abkühlung einer Flüssigkeit
  Z. B. die Abkühlung einer 0,75 1 Champagner-Flasche von 25 °C auf 8°C innerhalb einer Zeitspanne von 15 min.
• B: Anhaltende Kühlung eines Luftstromes
  Z. B. die Kühlung eines Luftstromes in einem Atemluftkühler
• C: Kalt- und/oder Warmhalten von Getränken und Lebensmitteln
  Z. B. Warmhalten einer Mahlzeit unter gleichzeitigem Kalthalten eines vorgekühlten Getränkes während einer längeren Transportzeit.
• D: Verzögern des Auftauprozesses eines gefrorenen Produktes.
  Z. B. Kalthalten (unter -10°C) einer Speiseeispackung nach der Entnahme aus dem Tiefkühlfach bis zum späteren Verzehr oder während des Transportes.

The cooling elements according to the invention can be divided into the following fields of application:

• A: Quick cooling of a liquid
  For example, the cooling of a 0.75 1 champagne bottle from 25 ° C to 8 ° C within a period of 15 min.
• B: Continuous cooling of an airflow
  For example, the cooling of an air stream in a breathing air cooler
• C: Cold and / or warm drinks and food
  For example, keeping a meal warm while keeping a pre-chilled beverage cold for a longer transport time.
• D: Delaying the thawing process of a frozen product.
  Eg cold holding (below -10 ° C) of an ice cream pack after removal from the freezer until later consumption or during transport.

In principle, these different applications can be met with cooling elements according to the invention. All applications are characterized in that a cooling element is stored for an indefinite period of time at any temperatures. At the start time of the cooling effect, the shut-off device is actuated. From this point on, working agent vapor can flow to the sorbent and be deposited by it. The sorbent gets hot because it liquefies and adsorbs the vapor within its crystal structure. The evaporator cools down and can be used as a source of cold. In the case of rapid cooling tasks (eg cooling of a liquid), the period of time will generally be insufficient to cool the sorbent appreciably. The working fluid vapor capacity will therefore be limited because of the hot sorbent temperatures unless admixtures act as heat buffers.
For cooling elements with a longer cooling time, the sorbent will be able to give off heat through the multi-layer film and, depending on the application, this heat can also be transferred to a product to be kept warm at a higher temperature level.

For applications in the deep-freeze area, sufficiently dimensioned flow channels and, if necessary, freezing point-lowering additives in the working medium must also be taken into account.

In order to minimize the heat flow from the hot sorbent to the cold evaporator, either isolation materials are provided or according to the invention to ensure a sufficient spatial separation of the two components.

Particularly inexpensive cooling elements can be achieved even if the evaporator is sealed in a gas-tight film. Under vacuum, the flow channels to the sorbent must be maintained. For this purpose, spacers are provided according to the invention, which allow the working medium vapor flow freely from the liquid working fluid and at the same time contact the cold surfaces with good thermal conductivity of the film.
Advantageously, this plastic flexible spacers can be used, which are adapted to the particular cooling task. However, the prerequisite is that the plastic spacers do not outgas during storage and worsen the vacuum. It is advantageous if polycarbonate or polypropylene are used as plastic, since these materials can be heated to higher temperatures before and during the manufacturing process and thereby degassed. It is particularly advantageous if this temperature increase takes place simultaneously with the heating of the sorption agent during the production process of the cooling element.
Spacers made of plastic can be produced inexpensively by the usual manufacturing methods such as deep drawing, extruding or blowing. Advantageously, in the manufacturing process, it is important to ensure that no later outgassing substances such as plasticizers are added.

• E: Dampfkanal vom Verdampfer zum Sorptionsmittel wird geöffnet.
  Z. B. Durchstoßen eines Folienbeutels, der das Sorptionsmittel umschließt.
• F: Flüssigkeitsleitung von einem Vorratsgefäß zum Verdampfer wird geöffnet.
  Z. B. Platzen eines Wasserbeutels und Austritt des Wasserinhalts in den Verdampfer. Von dort verdampft es dann und strömt weiter zum Sorptionsmittel.

In principle, the cooling elements can also be subdivided with respect to their shut-off device:

• E: Steam channel from evaporator to sorbent is opened.
  For example, puncturing a foil bag which encloses the sorbent.
• Q: Liquid line from a storage vessel to the evaporator is opened.
  For example bursting of a water bag and leakage of the water content in the evaporator. From there it evaporates and then flows on to the sorbent.

In the first case, the sorbent enveloping multi-layer film can be pierced. Suitable for this purpose are sharp-edged cutting tools, which strike a sufficiently large hole in the film. The cutting tool can act on the film both from the sorbent side and from the evaporator side. Since the films according to the invention are flexible, the cutting tool according to the invention is actuated by a deformation exerted externally on the films. This shut-off devices can be designed inexpensively and operated gas-tight.

In principle, the cutting tool must be sufficiently sharp to cut through the film in the necessary cross-section. Suitable z. B. cylindrically shaped expanded metals or sharp-edged molded parts made of plastic, which also additionally squeeze the sorbent located behind the film, or can move to cut through the film safely.

Of course, this also applies to the shut-off devices (case F), which only have to produce a small opening for the foil bag containing the liquid working medium. According to the invention, a film bag with the corresponding amount of working fluid and a connecting channel can additionally be molded onto the evaporator film. The channel provided between the sorbent and the liquid working medium can be sealed according to the invention by bending the film in this area one or more times, so that the polypropylene layers are pressed against each other. Together with the externally applied air pressure, this measure results in a sufficient seal between working fluid bag and the evaporator. The kinked channel thus forms a closed fluid valve. To open only the film in the channel area must be folded back into its original shape and optionally pressed by pressure on the working fluid bag, the working fluid in the evaporator.

A further advantageous embodiment is obtained when a separate bag with liquid working fluid is inserted within the evaporator. By external pressure on the evaporator shell of the working fluid bag can be made to burst and the liquid working fluid z. B. flow out into an evaporator fleece. The torn leakage point then forms the liquid valve.

In further embodiments, the evaporator may be disposed within the sorbent bag together with the sorbent. Only when the liquid valve opens the access of the working fluid in the evaporator, it can evaporate from there and continue to flow vapor to the sorbent.
The advantage of this shut-off device is that only a relatively small opening cross section for liquid working fluid is required. On the other hand, it is disadvantageous that the working medium must be able to homogeneously wet the evaporator sufficiently quickly without being entrained in liquid form in the sorber or even freezing on leaving the opening and thus blocking the further inflow.

It is known that the icing of water as a working fluid can be prevented by the admixture of a freezing point lowering agent. An admixture of sodium chloride may, for. B. Lower the freezing point to -17 ° C. It is already sufficient if the freezing point lowering means is arranged around the outlet opening of the water bag. Only when the water comes out of the mouth does it mix with the freezing point depressant in high concentration. A freezing is thereby excluded. Subsequent water then dilutes the solution and transports the working fluid to all areas of the evaporator.

A homogeneous distribution of the working fluid can also be achieved by a separate, finely branched channel structure, which distributes the working fluid homogeneously after passing through the shut-off device, before it could be entrained liquid by the steam flow. An inexpensive distribution can be achieved by a layer of finely delineated foil, which is arranged around the outlet opening.

Only in exceptional cases, the working fluid in the evaporator can be present in unbound form. Mostly it is distributed in an absorbent fleece and fixed by hygroscopic forces. Particularly low-priced materials are absorbent papers, as they are used in a great variety for household and industry for the absorption of liquids. The water-spanning nonwovens, like the spacers made of plastic or natural zeolite, must not outgas under vacuum and higher temperatures. Commercially available microfibers made of polypropylene are particularly suitable for this purpose. These fibers are made to absorb water and do not release the vacuum interfering gases.

Another solution opens the fixation of the working fluid in organic binders such. B. water lock from Grain Processing Corp. USA. Also advantageous may be the combination of several measures mentioned above.

For rapid cooling of a liquid in a liquid container, according to the invention, the outer surface of the liquid container is pressed onto the evaporator surface of the cooling element. This is done very efficiently if the liquid container is arranged directly inside the evaporator film. Due to the negative pressure between the multilayer film and the liquid container, the spacer can press the nonwoven fabric onto the container surface with a high pressing force and use a large part of the sometimes highly structured surface of the container for heat exchange.

However, this arrangement is only recommended if the container material itself does not emit gas and any existing closure for later pouring the beverage is sufficiently tight. If this can not be guaranteed or the outer side of the container is covered with gassing labels, the liquid container is first itself sealed in a gas-tight enveloping film under vacuum. This gas-tight packaging then allows a direct arrangement within the evaporator shell. The wrapping film for the liquid container need not withstand higher temperatures than the multi-layer film that surrounds the sorbent. For this purpose suffice z. As thin, metallized films with a more easily processed polyethylene layer.

Another solution according to the invention is to keep the evaporator structure flexible and to press the cold surface of the evaporator shell by means of separate, elastic pressing means surface on the outer surface of the liquid container. As external, elastic pressing means are stretch or shrink films or rubber bands. An advantage of this solution is that the liquid container remains partially visible and the cooling element does not have to be opened to pour out the liquid. The disadvantage, however, is a poorer heat transfer, since gaps between the outside of the container and the evaporator shell can remain, which hinder the heat transfer.

In order to maintain the necessary steam channel cross-section between the evaporator and sorbent filling despite the pending from the outside air pressure according to the invention the steam channel is formed and stabilized by several layers of a plastic network. There remains enough cross section for the flow between the network structure. When using polypropylene nets higher temperatures can be allowed without gas release. Due to the flexible structure of the nets, they also adapt optimally to the respective geometries.

Under liquid container all known and common vessels such as bottles, cans, bags, jugs, cardboard packaging, etc. understood that serve to hold liquids such as drinks, medicines but also chemical products. Of course, the liquid container may also contain solid or free-flowing products. Basically, the liquid container needs not be changed compared to its usual form and features. Thus, all previously used manufacturing and filling devices can be used unchanged.

The evaporator can take any shape and be made of any materials. Technically, it is necessary that during the cooling process, a sufficiently large opening for the escape of water vapor in the sorbent is formed or remains, working fluid remains in the liquid state at the point to be cooled, entrainment of liquid components is prevented and a good thermal connection to the cooling object persists.

Technically and economically interesting z. B. cooling elements in the form of trays for food transport with adjacent hot and cold shelves. These can be advantageously formed into shells into which the food can be filled directly. Also advantageous are cooling elements, in which the hot and the cold side face each other. These can be optimally used for separating hot and cold areas in cool boxes or insulated transport packaging. Between hot and cold zone, in these cases, an insulating spacer material can be inserted, which can also be arranged within the multi-layer film in an advantageous manner. The arrangement in a vacuum also very efficiently reduces heat conduction.

To produce cooling elements according to the invention, a sorbent bag open on one side is produced by thermal welding, for example, from a multilayer film. The sorbent bag is filled with sorbent, which is low in work equipment and without later releasing gases filled to less than 15 mbar, in particular less than 5 mbar, evacuated and sealed gas-tight. Subsequently, the vacuum sorbent bag is packed together with a shut-off device, a spacer and an evaporator fleece, which is impregnated with working fluid, in another envelope bag made of multilayer film. The envelope bag is then evacuated in a vacuum chamber to the vapor pressure of the working fluid and then also sealed gas-tight. When introducing the shut-off device, make sure that its opening device is not already triggered when the vacuum chamber is flooded.

The sealing of the film bag is usually carried out thermally by pressing hot sealing bars on the outer surfaces of the film until the internally superimposed polypropylene layers are soft and welded together. The welding process is usually carried out within a vacuum chamber under vacuum. But it is also known to evacuate the bag only inside by means of a suction device and then to weld. In addition to the thermal contact process, welding processes have also proved their worth with ultrasound.

According to the invention, a cooling element can already be added to the liquid container to be cooled later. This can, in order to keep disturbing gases from the cooling element away, be welded into an evacuated bag before being introduced into the enveloping bag itself. To ensure that during the storage time and also during the running at higher temperatures no cooling, the vacuum disturbing gases, all vacuum components should be heated during the evacuation process to at least 80 ° C or previously degassed at even higher temperatures be.

• Fig. 1 einen Sorptionsmittelbeutel in perspektivischer und geschnittener Darstellung,
• Fig. 1a eine vergrößerte Teilansicht der Mehrschicht-Folie aus Fig. 1.
• Fig. 2 in perspektivischer und geschnittener Darstellung eine Verdampferanordnung,
• Fig. 3 eine Ausgestaltung eines Abstandhalters,
• Fig. 4 ein Kühlelement zur Kühlung einer Getränkedose,
• Fig. 4a das Kühlelement nach Fig. 4 im Längsschnitt KK,
• Fig. 4b das Kühlelement nach Fig. 4 im Querschnitt SS,
• Fig. 4c das Kühlelement nach Fig. 4 in einem weiteren Querschnitt VV,
• Fig. 4d das Kühlelement nach Fig. 4 mit geöffnetem Dampfkanal,
• Fig. 5 ein Kühlelement zum gleichzeitigen Kühlen und Warmhalten,
• Fig. 5a das Kühlelement nach Fig. 5 im Querschnitt SS,
• Fig. 6 eine Kühlelementanordnung zum Abkühlen einer Flasche,
• Fig. 6a eine Draufsicht auf eine Zeolithplatte aus Fig. 6,
• Fig. 7 eine weitere Anordnung eines Sorptionsmittelbeutels und einer zu kühlenden Flasche und
• Fig. 8 eine Absperrvorrichtung mit einem Schneideisen in geschnittener Darstellung.

The drawing shows in:

• 1 shows a sorbent bag in perspective and sectional view,
• 1a is an enlarged partial view of the multilayer film of FIG. 1st
• 2 is a perspective and sectional view of an evaporator arrangement,
• 3 shows an embodiment of a spacer,
• 4 shows a cooling element for cooling a beverage can,
• FIG. 4a shows the cooling element according to FIG. 4 in longitudinal section KK, FIG.
• 4b, the cooling element of FIG. 4 in cross section SS,
• 4c, the cooling element according to Fig. 4 in a further cross-section VV,
• 4d shows the cooling element according to FIG. 4 with the steam channel open, FIG.
• 5 shows a cooling element for simultaneous cooling and keeping warm,
• 5a shows the cooling element according to FIG. 5 in cross-section SS, FIG.
• 6 shows a cooling element arrangement for cooling a bottle,
• 6a is a plan view of a zeolite plate of Fig. 6,
• Fig. 7 shows a further arrangement of a sorbent bag and a bottle to be cooled and
• Fig. 8 shows a shut-off device with a cutting iron in a sectional view.

The sorbent bag 1 according to the invention shown in FIG. 1 in a perspective and sectional illustration consists of a multi-layer film 2 which is thermally sealed at the edge of the bag 3. The evacuated interior contains the desorbed sorbent 4, which contains a broken, natural zeolite granulate.
The pre-sealed to a bag multi-layer film 2 was filled with a heated in a convection oven at 140 to 200 ° C granules and then evacuated in a vacuum chamber to a pressure of less than 5 mbar. Both gases and water vapor were pumped out of the zeolite crystal structure. The sorbent bag 1 was sealed gas-tight by means of welding tongs and the vacuum chamber was re-aerated. By dipping in a water bath, the sorbent bag 1 was cooled. To On cooling, the water vapor pressure within the bag is below 1 mbar absolute. Residual gases are not measurable and are not subsequently outgassed from the multi-layer film, since these too were heated to over 100 ° C during filling of the hot granular bed and released any gases. Heating during the subsequent sorption process to a similar temperature level will therefore release no further interfering gases.

It consists of an enlarged sectional view of the multi-layer film 2. It consists of the inside to the outside of a 80 micron thick polypropylene layer 5 on which by means of adhesive 6 8 microns thick aluminum layer 7 is adhered. A second adhesive layer 8 fixes a durable 30 micron thick polyester layer 9. The selection of layers and adhesives takes place from the viewpoint that the layers release under vacuum and at temperatures above 100 ° C no disturbing gases, the welds are not fragile and the sharp-edged, Zeolite-containing sorbent 4 can not pierce the film. According to the invention, a further polyester layer can also be adhesively bonded between the polypropylene layer 5 and the aluminum layer 7.

Fig. 2 shows a perspective and sectional view of an evaporator. This consists of a spacer 11, which is made of a flexible, extruded Polycarbonatformstück and on the smooth outer side 12 a multilayer film 13 rests and on the structured inner side 14 flow channels 15 are kept free for the working medium vapor. Between a second multi-layer film 16, which covers the cold surface of the evaporator and the spacer 11, a fibrous web 17 is inserted, which is impregnated with liquid working fluid. The web 17 contains microfibers made of polypropylene. The two multilayer films 16 and 13 are thermally welded together at the seam 10 with a sealing seam width of at least 5 mm.

In Fig. 3, a further embodiment of a spacer 18 is shown. This is made of a 1 mm thick polypropylene plate 21, in which by means of a deep drawing spacer studs 19 were drawn, which space a nonwoven 20 so that water vapor which evaporates from the nonwoven 20, unhindered in the channel space between nonwoven 20 and polypropylene plate 21 can flow.

4 and 4a to 4d show a cooling element which contains a beverage can 24 with 0.5 l content at the top and a sorbent bag 22 with 400 g natural clinoptilolite at the bottom. Beverage can 24 and sorbent bag 22 have been sealed in a pouch 23 under vacuum. The wrapping bag 23 is made of a piece of multi-layer film, which was simply folded and welded to the lower transverse seam 26 and the longitudinal seam 27. After introducing the sorbent bag 22, a piercing tool 25 and provided with an evaporator 29 beverage can 24, the envelope bag 23 was set in a vacuum chamber to a pressure below the vapor pressure of the working fluid and then welded at the upper edge 28. So that the piercing tool 25 does not penetrate the film of the sorbent bag 22 in the piercing region 30 when the vacuum bag is flooded, two spacers 31 made of foamed polypropylene, each with an adhesive strip 32, are fixed outside the outer bag 23. The spacers 31 prevent the puncturing tool 25 from severing the sorbent bag 22 despite negative pressure. The opening of the flow channel takes place only after removal of the adhesive strips 32, the spacers 31 are removed and thus the piercing tool 25, as shown in Fig. 4d, has penetrated into the sorbent bag 22 and punched out the lancing portion 30. The piercing tool 25 consists of a small piece of expanded metal, which is formed into a cylinder. At its upper end it touches the beverage can 24, its lateral support is ensured by a channeled fixing plate 33, which at the same time holds the steam path from the evaporator 29 through the piercing tool 25 into the sorbent 34 after removal of the spacers 31.

The structure of the evaporator 29 can be seen according to the section VV in Fig. 4c. To the beverage can 24 is a 30 g water-soaked paper wrapper 35 is wound, which in turn is pressed by a spacer 36, analogous to the spacer 11 of FIG. 3, on the outer wall of the beverage can 24. The spacer 36 is in turn pressed onto the beverage can 24 by the enveloping bag 23 on which the external air pressure rests. This ensures optimal thermal contact of the evaporating body of water with the contents of the can.

Finally, Fig. 4b shows the section SS of Fig. 4. The sorbent 34, in this case natural zeolite, is packed in the sorbent bag 22 as explained in the description of Fig. 1. Around the sorbent bag 22, the film of the outer bag 23 nestles. This also contains a barrier layer of aluminum and a sealable layer of polyethylene or polypropylene. If it is ensured that no gases escape from the surface or the lid sealing of the beverage can 24 into the evaporator region, the beverage can 24 does not have to be additionally surrounded by a gas-tight, evacuated film.

During the production of the cooling element, it must be ensured that all media within the vacuum system release no or only harmless quantities of gas. Advantageously, the sorbent bag 22 is first pushed into the envelope bag 23. Subsequently, the spacers 31 are fastened by means of the adhesive strips 32 from the outside.
To the lateral surface of the beverage can 24, the paper wrapper 35 is wound and soaked with the working fluid water. Based on the sorbent mass this is 7.5% water. It follows the spacer 36 made of polypropylene and the fixing plate 33, in which the piercing tool 25 is clamped. The fixing plate 33 and the spacer 36 can be conveniently fixed on the beverage can 24 by shrink films (not shown).
The thus prepared beverage can 24 is pushed into the outer bag 23 until the two spacers 31 pending on the fixing plate 33. The thus-stocked envelope bag 23 is now evacuated in a vacuum chamber until some water vapor flows out of the working medium water. This working medium vapor flow degasifies the working medium itself and also tears all other gases out of the enveloping bag 23. After it has been ensured that all disturbing gases have been pumped off, the enveloping bag 23 is thermally sealed in the region of the upper edge 28 by means of welding bars.
After venting the vacuum chamber, the finished cooling element can be removed. In order to be sure even after a long storage time that the cooling element is welded gas-tight and no foreign gases were released, the element can in turn be placed in a vacuum chamber and evacuated. In a functionally reliable cooling element, the enveloping bag 23 will not bulge until the chamber pressure drops below the water vapor pressure.

To activate the cooling element, the two spacers 31 have to be withdrawn, which are firmly clamped between the sorbent bag 22 and the fixing plate 33 because of the negative pressure. Thanks to the flexible spacer material, the film of the outer bag 23 and the sorbent bag 22 is not damaged despite sharp-edged zeolite granules. Due to the internal negative pressure, the piercing tool 25 will immediately penetrate into the lancing region 30 of the sorbent bag 22, cut out a portion of the film material and release the steam channel for the upcoming water vapor. Within a few minutes, the water in the paper sheath 35 will cool to about 0 ° C and heat the sorbent 34 to over 100 ° C. After about 10 minutes, the content of the beverage can 24 is cooled by about 18 Kelvin and the sorbent 34 uniformly hot. Occasional shaking of the beverage can 24 accelerates the cooling of the beverage within the can. About a notch on the weld along the longitudinal seam 27 of the envelope bag 23 can be separated and the cold beverage can 24 are pulled out of the evaporator 29. The used sorbent granules can be used to improve the soil or pond water quality or be disposed of together with the film material in the residual waste.
From the water mask in the paper wrapper 35 about 18 g have been evaporated and sorbed by the sorbent 34. With a filled zeolite mass of 400 g, this results in a loading of only 4.5%. However, since the zeolite filling can hardly give off heat to the environment in the short cooling period, a significant drop in temperature and a concomitant additional water adsorption is not possible. For this reason, a natural zeolite is well suited for the cooling element described here.

Fig. 5 and 5a show a flat cooling element, which allows not only the cold from the evaporator 42 at the same time the use of heat from the sorbent. A flat sorbent bag 40 contains a zeolite plate 41 of synthetic zeolite and an evaporator 42 without interposed shut-off device. The evaporator 42 includes an anhydrous web 43 and a spacer 44, which is constructed analogously to the spacer of FIG. The zeolite plate 41 has been formed from powdered Na-A zeolite with the addition of binder. In it flow channels 45 are incorporated in the lower region, which allow the forwarding of the steam flow from the spacer 44 in the sorbent. The working fluid water 47 is located in a water bag 46, which communicates via a connecting channel 48 with the evaporator 42 and is also part of the sorbent bag 40. In the region of the mouth of the connecting channel 48 in the evaporator 42, a film piece 50 is arranged, which ensures that inflowing water is directed into the web 43 and does not reach the flow channels of the spacer 44 in the liquid state. In addition, 48 g of salt are inserted into the web 43 in the mouth region of the connecting channel 48. According to the invention, a single multi-layer film bag is used which encloses or forms both the sorbent, the evaporator 42, the connecting channel 48, the working medium water 47 and the shut-off device. The shut-off device is that the connecting channel 48 is bent from its original plan position by 180 ° upwards. The water bag 46, which assumes the position shown in dashed lines in FIG. 5 during production, thus lies on the evaporator 42 during the storage time. Due to the sharp fold 49, in whose area the two superposed polypropylene layers are strongly squeezed against each other, a very inexpensive shut-off device has arisen which can be folded back by folding the water bag 46 into the starting position (dashed position in FIG. 5 and position in FIG. 5 a) can easily open another tool by pressing on the water bag 46 from the outside.
To produce the cooling element, the zeolite plate 41 is heated in a circulating air oven to temperatures between 150 and 200 ° C. The hot zeolite plate 41 is then introduced together with the heated to about 80 ° C evaporator components in the partially prefabricated sorbent bag 40. The sorbent bag 40 is then welded so far that only the connection channel to the water bag 46 and the water bag itself have a suction opening to a vacuum chamber. By evacuating the vacuum chamber to less than 5 mbar, the pressure within the sorbent bag 40 is also lowered. As a result, residual water evaporates from the zeolite, the steam flow of which expels air and gases released from the hot components through the connecting channel 48. Then, the connecting channel 48 can be kinked. The water bag 46 can now be filled with degassed water and then welded gas-free.

To take the cooling element into operation, only the water bag 46 is returned to its original position and thus the folding 49 straightened. Driven by the water vapor pressure in the water bag 46, water now flows through the connecting channel 48 into the fleece 43. It dissolves the salt crystals located there, as a result of which the freezing point is lowered to almost -17 ° C. By inflowing water, the salt solution is further passed into the fleece, from where it can evaporate. The vapor is directed into the zeolite plate 41 via the channels maintained by the spacer 44 and sorbed exothermically. The heat of sorption heats the zeolite plate 41 to over 100 ° C. The web 43 cools by the evaporative cooling to temperatures below the freezing point. The cooling element can thus be used, for example, in the region of the zeolite plate 41 for keeping food warm and in the region of the evaporator 42 for keeping cold drinks. After use, it can be sent to the residual waste.

Without a graphical representation, it should be noted that the evaporator 42 of the cooling element of FIG. 5 can be brought into a cylindrical shape which is suitable for receiving a can or a bottle. To get a good thermal contact between bottle surface and sorbent bag, both can be pressed together by means of stretch films or rubber bands.
It is also very efficient to place the bottle and the cooling element in an additional bag, which is then evacuated. The heat transfer from the evaporator to the bottle is significantly improved by the then applied air pressure.

Finally, FIG. 6 shows further components of a cooling element according to the invention for rapid cooling of a bottle 53 filled with a beverage. The bottle 53 shown in cross section is in turn driven by a cylindrically moldable spacer 54 which presses a nonwoven 52 onto the cylindrical bottle part and a fixing element 55 Surrounding receiving a cutting tool 56. The bottle 53 itself may first be sealed in a gas-tight - not shown - evacuated film, so that from the cork 61 of the bottle 53 diffusing gases that can not affect the necessary vacuum function. A sorbent bag 57 contains 6 disk-shaped zeolite plates 58, one of which is shown in plan view in FIG. 6a. The plates contain centrally steam channel holes 59 through which the water vapor is fed to radial channels 60. From the radial ducts, the steam can then quickly penetrate into all areas of the sorbent via thin gaps, which inevitably remain between the plates during stacking. The uppermost plate 58 has a larger steam channel hole so that the cutting tool 56 and the multi-layer film punched out by it can find room.
The other, necessary for the operation of the invention components are not illustrated by drawings. They result analogously from the illustrations and descriptions of FIGS. 4 to 4d.

Fig. 7 shows a further, space-saving arrangement of a cooling element for cooling a bottle 62. In the sorbent bag 63, a recess is formed, in which the bottle neck 64 and the shut-off device 65 are arranged. The sorbent bag 63 advantageously has the diameter of the bottle 62, not shown evaporator. The shut-off device forms a cutting tool 65, which can perforate the multilayer film of the sorbent bag 63 only by manually increased axial pressure. The remaining components are not shown here for the sake of clarity. For them and the manufacturing and cooling method, the description of FIGS. 4 to 4d applies analogously.

Fig. 8 shows a shut-off device in which a die 80 can pierce a sorbent bag 81. The sorbent bag 81 contains a zeolite 82 in spherical form. The cylindrically shaped die 80 has at its one end a knife edge 83 which is designed to sever the film of the sorbent bag 81. So that the separation does not happen unintentionally, a protective film 84 is placed between knife edge 83 and sorbent bag 81, which ensures by its nature that the cutting iron 80 only the sorbent bag 81 severed when additional external forces in the direction of arrow A on the other end of the cutting iron 80 and not already by the external air pressure. This other end is provided with a cap 85 which projects beyond the diameter of the cutting iron 80 and supports the outer enveloping bag 86. The diameter of the cap 85 is slightly larger than the punched hole 88 in a working medium vapor channel disposed between sorbent bag 81 and wrapping bag 86. In order to maintain the necessary vapor cross-section, it is made up of several layers of a net 87 of polypropylene filaments. Through this multi-layer structure remains within the network structure sufficient flow cross-section for the working medium vapor although the difference between the working medium vapor pressure to the outside air pressure is present on the steam channel. The cutting iron 80 has in its cylinder wall a plurality of windows 89 through which the working medium vapor from the steam channel can flow into the die. By pressure on the enveloping bag 86 in the direction of arrow A, the protective film 84 is severed together with the sorbent bag from the knife edge 83 of the cutting iron 80. The stamped parts are pushed by the rolling zeolite 82 into the interior of the cutting cylinder and thus release the steam path. The die 80 can be so far pressed until its cap 85 rests on the edge of the holes 87 networks. The flexible envelope bag 86 folds without leaking.

Claims (21)

A cooling element comprising a sorbent (4) capable of sorbing, under vacuum, a vaporous working fluid which evaporates from a liquid working fluid in an evaporator (29) and a shut-off device which prevents fluid vapor from flowing to the sorbent (4) until the start of the cooling process .
characterized in that
the sorbent (4) is sealed in a sorbent bag (22) containing a multilayer film which in turn contains at least one metallic layer or layer. Cooling element according to claim 1,
characterized in that
the multi-layer film contains a polyester layer with a layer thickness of 12 to 50 μm. Cooling element according to one of the preceding claims,
characterized in that
the multilayer film contains a polypropylene layer between 50 and 100 μm thick. Cooling element according to one of the preceding claims,
characterized in that
the multilayer film can be sterilized at temperatures up to 120 ° C. Cooling element according to one of the preceding claims,
characterized in that
the sorbent (4) contains zeolite and in particular natural zeolite. Cooling element according to one of the preceding claims,
characterized in that
the shut-off device includes a cutting tool (25) adapted to sever the multilayer film. Cooling element according to one of the preceding claims,
characterized in that
the evaporator (29) contains a fleece from which evaporate the working fluid can and a spacer (36), which forms steam channels and
that the evaporator (29) is enclosed by a flexible and gas-tight envelope bag (23) on which the external air pressure rests. Cooling element according to one of the preceding claims,
characterized in that
the flexible, gas-tight envelope bag (23) also encloses the sorbent bag (22). Cooling element according to one of the preceding claims,
characterized in that
the sorbent bag (22) also envelops the evaporator. Cooling element according to one of the preceding claims,
characterized in that
the enveloping bag (23) also encloses a container whose contents are to be cooled. Cooling element according to one of the preceding claims,
characterized in that
the sorbent bag (22) and the cutting tool (25) are arranged so that the external air pressure is used to actuate the cutting tool (25) and the wrapping bag (23) is deformable for this purpose. Cooling element according to one of the preceding claims,
characterized in that
the sorbent bag (22) is shaped and sealed to form a water bag (46) which communicates with an evaporator (42) via a connection channel (48). Cooling element according to one of the preceding claims,
characterized in that
the connecting channel (48) in the folded state serves as a closed shut-off device and, in the extended state, allows working fluid to flow from the water bag (46) into the evaporator (42). Cooling element according to one of the preceding claims,
characterized in that
the shut-off device contains a cutting tool, which is arranged between the enveloping bag and the sorbent bag and cuts the sorbent bag when exposed to external force and releases the access of working medium vapor into the sorbent filling, without thereby causing the deforming enveloping bag to leak. Cooling element according to one of the preceding claims,
characterized in that
the Arbeitsmitteldampfkanal is formed of flexible plastic nets, which are superimposed in several layers and withstand the external pressure. Method for producing a cooling element according to one of the preceding claims,
characterized in that
hot sorbent (34) is filled into the sorbent bag (22), the still open sorbent bag (22) is then evacuated so long from the sorbent (34) evaporating working fluid residual gases from the sorbent bag (22) has displaced and then under vacuum Sorbent bag (22) is sealed gas-tight. Method for producing a cooling element according to one of the preceding claims,
characterized in that
the sorbent (34) at temperatures between 120 and 250 ° C, in particular between 150 and 190 ° C in the sorbent bag (22) is filled. Method for producing a cooling element according to one of the preceding claims,
characterized in that
the pressure during evacuation of the outer bag (23) is lowered below the working medium vapor pressure. Method for starting the cooling function of a cooling element according to one of the preceding claims,
characterized in that
by manual deformation of the flexible, gas-tight outer bag (23) the shut-off device is triggered. Method for starting the cooling function of a cooling element according to one of the preceding claims,
characterized in that
outer spacers (31) are removed on the cooling element and thereby the sorbent bag (23) is pulled by the negative pressure against the cutting tool (25). Method for starting the cooling function of a cooling element according to one of the preceding claims,
characterized in that
a fold (59) within the sorbent bag (22) is smoothed, whereby liquid working fluid from the water bag (46) can flow into the evaporator (42).

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