DE102010047371A1 - Sorption cooling elements - Google Patents

Abstract

Cooling element (20) for cooling a vessel (30) with a filling quantity of sorbent (10), which can sorb a vaporous working medium under vacuum, which evaporates from a liquid working medium quantity in an evaporator (3) and with a feed device (40) at the start of each cooling process, a portioned amount of working fluid can flow into the evaporator and the feed device (40) during each cooling process the amount of working fluid flowing into the evaporator (3) to a maximum of a quarter of the sorbent (10) at T = 50 ° C and p = 6 mbar can limit the maximum amount of working fluid that can be absorbed and the amount of working fluid in the cooling element (20) enables at least four successive cooling processes, and the evaporator (3) is equipped with a flexible heat exchanger surface for absorbing heat from dockable vessels (30), which can be detached by means of detachable pressing agents (27 ) onto the successively docked vessels (30) is pressed.

Description

The invention relates to sorption cooling elements for cylindrical vessels with a gas-tight multilayer film for cooling vessels in which by evaporation of a working fluid and sorption of the working medium vapor in a sorbent under vacuum cold is generated and methods for producing and starting these cooling elements.

Adsorption devices are devices in which a solid adsorbent sorbs a second, boiling at lower temperatures, the vaporous working medium, under heat release (sorption). The working fluid evaporates in an evaporator while absorbing heat.

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 sorption heat 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.

Similar solutions are z. B. in the EP 01902261 , of the US 5,197,302 or the WO 2007/006065 disclosed. Common to all is the use of steam valves and the use of heat sinks to keep the temperature rise of the sorbent low. At elevated temperature, namely, the ability of the sorbent significantly decreases to accumulate additional work equipment. In order to minimize the use of relatively expensive and equally voluminous sorbent materials such as PCM (Phase Change Material) are essential.

The mass ratio between sorbent and PCM is 1: 1.5; d. H. to a mass of 100 g of active sorbent, add 150 g of PCM. The total mass is thus 250 g. There are also housing components, a valve and the working fluid. In the case of zeolite and water, this total mass of at least 250 g can adsorb only about 15 g of water. The maximum amount of refrigerant that can be generated amounts to 37 KJ. Even if this amount of refrigerant would be transferred lossless on a drink, so that a can with 330 ml content can be cooled by a maximum of 27 K. Consequently, in all known technical solutions, the additional volume and additional weight almost reach that of the beverage to be cooled. The cost of cooling thus easily exceed the cost of the drink.

The US Pat. No. 6,474,100 B1 finally describes a self-cooling cooling element on 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 EP 08008007 Finally, describes cooling elements for cooling a glass bottle from 25 ° C to 10 ° C within a period of 20 minutes. The working fluid is introduced in two separate subsets. Cooling is possible twice. The glass bottle can be separated from the cooling element.

The object of the invention are cost-effective sorption cooling elements and methods for their preparation and for cooling.

This object is achieved by the characterizing features of claim 1. The dependent claims show other inventive devices and methods.

The cooling element according to the invention does not use heat storage materials. The released heat of adsorption is rather buffered in an amount of sorbent at least four times excessive. Although this requires four times the cost and volume of sorbent material, on the other hand, the cooling elements can cool not only once but at least four times in succession, provided that heat is transferred to the environment in between. With a cooling system according to the invention four beverage cans can be cooled. To cool four beverages with the prior art, four separate refrigeration systems are necessary. The invention thus saves the entire, additional heat storage mass, three evaporator structures, three valves and the necessary connection and insulation elements. Based on the cooled beverage volume, this means a significant material and cost savings. The user is also free to choose and cool the beverage can to cool yourself. Vessel and cooling do not form an indivisible unit in the invention.

Since, according to the invention, at least four vessels can be cooled, it is also necessary to dock four vessels in succession to the cooling system and to remove them again easily after the cooling process. According to the invention, this is done by a flexible evaporator geometry and by means of pressing, which press the evaporator good heat-conducting on the cylindrical outer surfaces of the vessels.

According to the invention, the sorbent, the evaporator and the feed device are enveloped by a multilayer film. The evaporator contains at least one fleece and a flexible, vapor-permeable structural material. Both together form under vacuum a smooth as possible, flexible design that can be pressed accurately and large area of the vessel to be cooled. The structural material distributed at the start of cooling the liquid working fluid over a large area in the fleece and directs the working medium vapor in the sorbent. According to the invention, the structural material leaves open a flow cross section which is dimensioned such that the working medium in the nonwoven fabric can not normally freeze during the cooling process. This is especially important when working with water. Ice significantly reduces the heat transfer from the vessel to the evaporator. However, too narrow a flow cross-section limits the cooling capacity. The cooling time will be considerably longer. Ideal are evaporation temperatures between 7 and 0 ° C. The ideal flow area is given when, with warm vessel fillings (above 30 ° C), the initial vaporization temperature is about 7 ° C and then drops to as low as 0 ° C when the vessel is further cooled.

By using a structural material that can be produced at low cost, on the one hand, a flexible construction of the evaporator can be realized, which can be optimally adapted to particular cylindrical geometries. On the other hand, the necessary flow channel from the evaporator to the sorbent can be realized in the required cross-section. In order to achieve a sufficiently rapid cooling, the flow cross-section must have at least an area of 1 cm ² . With water as working fluid, a cooling capacity of up to 50 watts can be achieved.

The multi-layer film used for the gastight vacuum envelope encloses all components necessary for operation and storage time. It can be manufactured in one piece and allows the necessary bending freedom under vacuum to the internal flexible components. With an aluminum barrier layer in the multilayer film, storage times of more than two years are possible without an excessively large amount of gas diffusing through the film during this period.

For rapid cooling of liquids within the vessels, the evaporator surface of the cooling element is pressed onto the outer surface of the vessel according to the invention. The evaporator is designed to be flexible and pressed the cold evaporator surface by means of separate, elastic pressing means flat on the outer surface of the liquid container to use a large part of the sometimes structured surface of the container for heat exchange. As a pressing means are z. As detachable tapes, rubber bands or hook and loop fasteners of any kind. When creating the cooling element to the vessels is important to ensure that the heat transfer is not affected unnecessarily by gaps and wrinkles in the film material.

Within the evaporator flexible plastic structural materials can advantageously be used, which are adapted to the respective cooling task. The prerequisite is, however, that the structural materials do not outgas during the storage time and thereby impair the vacuum. It is advantageous if polycarbonate (PA), polyethylene terephthalate (PET) or polypropylene (PP) are used, since these materials were heated to higher temperatures before and during the manufacturing process and thereby degassed. Plastic structural materials can be inexpensively manufactured by the usual manufacturing techniques such as deep drawing, extruding, weaving or blowing. Advantageously, it is important in the manufacturing process that no later outgassing substances such as plasticizers or dyes are added. Extruded meshes and meshes of polypropylene, which are used in one or more layers, have proven to be particularly effective, on the one hand providing the necessary flexibility with respect to deformation and, on the other hand, providing rigidity against the air pressure applied from outside over the multilayer film. Particularly suitable polypropylene structural materials are sold by Tenax Germany. The product OS 102 is a diamond-shaped grid that leaves ideal geometries for the working medium vapor flowing in the lattice plane open and supports the externally applied multi-layer foil. Single or multi-layer layers of this grid can be used particularly advantageous as a structural material. In order to ensure very smooth heat exchanger surfaces and sufficiently large flow cross sections, it may be advantageous to additionally insert a finely structured, firm woven or knitted fabric of polyester between nonwoven and structural material. This may possibly be achieved smoother surfaces relative to the vessel. On the side facing away from the fleece can also be a stabilizing cover plate be inserted to bridge too far carrier distances of the structural material relative to the external atmospheric pressure. Advantageously, PP films having a thickness of approximately 0.5 mm have proven to be suitable for the cover plate. In general, however, the structural material should consist of one piece and fulfill all supporting functions self-supporting.

As vessels all common containers such as bottles, cans, barrels, bags, jugs, etc. are understood, which serve to hold liquids such as drinks, medicines but also chemical products. Of course, the vessel may also contain solid or free-flowing products. Basically it does not have to be changed compared to its usual form and equipment. Thus, all previously common manufacturing processes, filling devices and distribution channels for the vessels can be kept unchanged.

According to the invention, the evaporator together with the internal structural material and fleece is pressed around the cylindrical outer jacket of the vessels. Since the inner radius of the all-enveloping multilayer film is thus smaller than the outer radius, it is particularly important to ensure that the resulting difference between the outer and inner circumference of the film geometry is recorded. In order to avoid wrinkles along the shorter inner circumference, the foil blank along the vessel sheath is made segmentally wider than would be geometrically necessary. The supernatant film material can then compensate for the length differences by folding in this area. The relevant contact surfaces for the heat transfer remain wrinkle-free. These compensation surfaces to accommodate the differences in length can be turned over in the course of the manufacturing process in less disturbing or non-visible areas.

Sorbents can reach temperatures of over 100 ° C during the sorption process. For such high temperatures, the multilayer films commonly used in the packaging sector are less suitable. In particular, the polyethylene layers frequently used for sealing become soft even at 80 ° C. and cause the sheath to leak under vacuum. Polypropylene sealing layers, on the other hand, can withstand significantly higher temperatures. Its melting point is above 150 ° C. At higher temperatures, sharp edges on the sorbent and structural material can easily lead to impermissible leaks. This risk can be met according to the invention by polyamide and / or polyester sheaths within the multilayer film. Polyester and polyamide films are particularly tear and puncture resistant. The actual gas barrier is ensured by a layer of thin metal foils or metallized layers. For this purpose, thin aluminum foils with a layer thickness from 7 μm have proved suitable. Less dense are metallized plastic films. Nevertheless, with short storage periods, the use of these metallized films is possible, especially since they are cheaper compared to the metal foils. The individual layers of a multilayer film are bonded together by adhesive. Commercially available adhesives contain solvents which are not completely removed from the adhesive layer during bonding. Over long periods of time, these solvents then diffuse through the internal layers, particularly the polypropylene 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 and vacuum. According to the invention, multilayer films with polyester or polyamide layer thicknesses of 12 to 50 μm, an aluminum layer thickness of at least 7 μm and a polypropylene layer thickness of 50 to 100 μm are used. Use find such films z. As in the packaging of foods that are sterilized after packaging for preserving at temperatures of about 120 ° C. Even more stable multilayer films are obtained when a further approximately 15 microns thick polyester or polyamide layer is bonded between the aluminum and the polypropylene layer. Sharp or pointed sorbent particles then can not penetrate to the gas barrier, the aluminum layer.

When filling solid sorbent in bags, dust forms, which deposits on the inside of the film. Dust on the subsequent welds 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 encase hot, sharp-edged and dust-releasing sorbent without further, protective intermediate layers 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 the sorption reaction or even completely stop it. The sealing seams should therefore have a width of at least 5 even better but 10 mm.

Inventive multilayer films are z. B. via the companies Cellpack, Switzerland or Pawag, Austria. When using such films cooling elements with a leakage rate of less than 1 × 10 high-7 mbarl / sec are possible. The Shelf life thus reaches several years without the cooling effect being restricted.

The welding 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. Particularly noteworthy are stand-up pouches, bags with pouring openings, pouches with cardboard reinforcement, tear-open pouches, pouches with peel effect for easier opening and bags with valves. All of them can be advantageous with their specific properties for the cooling elements according to the invention. However, bag geometries without branches or foil overlaps have proven to be useful. In particular, simple tube geometries are to be preferred in terms of manufacturing technology. According to the invention, it is assumed in the production of a tubular film bag, the longitudinal sides may be structured to allow the compensation surfaces for wrinkles or the absorption of the sorbent. Space for the evaporator is provided in the middle region of the film tube, while the sorption material and the feed device are accommodated in the two opposite tube ends.

The sorbent used is advantageously zeolite. This can reversibly sorb in its regular crystal structure up to 36% by mass of water. In the application according to the invention, the technically feasible water absorption is between 16 and 20 percent by mass, since the sorbent is not filled in completely dry. In practice, a moisture content of more than 3 percent by mass is to be assumed before the first cooling step. During a cooling process, the sorbent with water vapor of about 7 mbar (evaporator temperature about 1 ° C) in contact. Zeolites adsorb water vapor to thermodynamic equilibrium with heat release. The equilibrium is reached when the maximum zeolite temperature is reached under the prevailing vapor pressure. In the first cooling step, commercially available zeolites without heat removal and under 7 mbar steam pressure heated to a maximum of 125 ° C. The maximum adsorbable amount of water vapor is then 4% by mass. Together with the initial load, this results in an intermediate load of about 7 percent by mass. After a subsequent cooling phase, the next adsorption phase can be started. Again, the temperature rises, but only to about 98 ° C. The adsorbed amount of water vapor is again about 4 percent by mass. Although in the second cooling step less adsorption could be buffered in the sorbent (heating only to 98 ° C and not to 125 ° C), also about 4 percent by mass of water vapor are adsorbed. The explanation lies in the fact that, on the one hand, the adsorption heat is lower in the case of higher pre-loads and, on the other hand, that even the larger water load itself can absorb more buffer heat. In the third cooling process, the processes are similar. Here, too, approx. 4% by mass of water is taken up again, although the temperature of the zeolite filling only rises to approx. 79 ° C. The reason for the similarly high water absorption is also due to the even greater water pre-charge and the even lower adsorption heat. Also in the fourth cooling process again up to 4 percent by mass of water vapor are adsorbed, although the increase in temperature at 60 ° C comes to a standstill. All measured data were based on an initial sorbent temperature of 25 ° C.

Theoretically, another, but lower water absorption would be possible. Practically, however, so that a sufficient cooling result can be achieved only after a long wait, if additional heat of adsorption can be dissipated via the container walls of the cooling element.

According to the invention, therefore, the minimum amount of sorbent used is designed according to the required cooling amount of a single cooling step. For the rapid cooling of a 250 ml beverage can with a cooling element according to the invention this is exemplified below:
The contents of the can (250 ml) should be cooled from 30 ° C to 5 ° C in about 12 minutes. For a 25 K temperature drop, together with losses to the environment, cooling of vaporizer and vaporizer masses and internal irreversibilities (inhomogeneous water distribution, entrained water droplets, etc.) provide 32 kJ of evaporative coldness. This amount of cold is achieved by the evaporation of 13 g of water. With a maximum water absorption of 4 percent by mass, therefore, about 325 g of zeolite are to be provided. With this amount of zeolite, the other three cooling operations are possible, provided in between enough time for the heat to be released to the environment. It also follows from the results that any number of coolings above four can be realized by a small increase in the amount of zeolite. Increasing the amount of zeolite, for example, by a quarter of 325 g, ie by about 81 g to a total of 406 g so already 5 cans can be cooled with a single cooling element. For 8 beverage cans, therefore, a quantity of zeolite of 8 × 81 g = 648 g would have to be provided. It is also easy to understand that with this amount of zeolite, 2 beverage cans can be cooled immediately in succession without any interim heat release to the environment. After cooling the respective second can, an intermediate cooling is to be expected. Of course, the simultaneous cooling of two vessels is possible with this 8-fold amount of zeolite. In this case, however, two evaporator transfer surfaces would be necessary.

To emphasize only the weight advantage over the prior art, the zeolite mass for 8 vessels of 648 g is divided into eight conventional, self-cooling beverage cans. The then additionally necessary heat buffer mass adds up to almost 1 kg alone.

It will be apparent to those skilled in the art that for the sorbent zeolite and the working fluid water for all cooling tasks, the same relation can be used: zeolite can absorb a maximum of 4% by mass without additional heat buffering. One after the other (with intermediate cooling), at least four coolings are possible, so that together at least 16% by mass of water vapor adsorption can be realized. Depending on the container size to be cooled (= beverage volume) and depending on the desired temperature reduction, the necessary amount of water to be evaporated is calculated. This amount of water can then amount to a maximum of 4% of the zeolite. Thus, the minimum amount of zeolite is easy to calculate. For at least four coolings is then always sufficient sorbent available.

Zeolite is a crystalline mineral that consists of a regular skeletal structure of silicon and aluminum oxides. This 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 (and therefore the heat of adsorption) depends on the amount of water already contained in the framework structure and the temperature of the zeolite. Of the synthetic zeolite types, especially the types A, X and Y are used, each in their inexpensive Na form.

For all types of zeolites, there is a risk that, depending on the synthesis processes and starting materials, they contain admixtures which release gaseous constituents in a vacuum, and in particular at elevated temperatures, which influence the cooling process. The problem of gas release is solved by the fact that zeolites are heated in the manufacture of the cooling element at least to the later sorbent temperature and at the same time placed under the then prevailing 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. In order to be able to carry out this treatment within the multilayer film, the gas-tight multilayer films with an inner polypropylene layer and at least one polyester layer are used according to the invention.

In addition to the combination of zeolite / water, other solid sorption substance combinations are 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 work in a vacuum, they can also be welded in multilayer films according to the invention.

According to the sorbent amount is to be 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 multilayer films. After evacuation, they form a hard, pressure and dimensionally stable sorption container that retains the shape required for evacuation. Also advantageous are zeolite powder preformed, stable zeolite blocks, in which the flow channels are incorporated and whose shape is adapted to the desired cooling element geometry. The stable zeolite blocks may have cavities in the region of the later steam opening in order not to obstruct the flow through the steam channel.

In direct contact of the sorbent with the multilayer film, the heat of adsorption is discharged 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. The waiting time before the following cooling process can thus be shortened.

Since the heat transfer to an air flow from the outside of the multilayer film is of the same order of magnitude as the heat transfer of a sorbent granulate to the inside of the film, in principle large film surfaces without ribbing are recommended, for example in cylinder, plate or tube geometries. 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.

To control the heat flow from the hot sorbent to the nearby To minimize cold evaporators, either provide insulation materials or pay attention to a poorly heat-conducting connection between the components. It is also desirable to thermally isolate the vessel and the surrounding evaporator. If the vessel and the evaporator are exposed to the ambient air uninsulated, condensation of water vapor from the air on the cold surfaces may occur. On the one hand, moisture that precipitates between the vessel and the evaporator can improve the heat transfer, but on the other hand, a considerable part of the cooling capacity for this condensation is lost.

Particularly inexpensive cooling elements are possible if the thermal insulation can be combined with the pressing means. Insulation materials often have a resilient restoring force against compression. This restoring force can be used according to the invention as a resilient compensation medium in order to distribute pressure forces applied on one side more uniformly to the entire evaporator contact surface.

The feed device has the task in each cooling process to limit the amount of working fluid flowing into the evaporator to a maximum of a quarter of the maximum amount of working medium that can be absorbed by the sorbent at T = 50 ° C. and p = 6 m bar. According to the invention, the working fluid can be distributed at least to four individual bags, since the amount of sorbent can adsorb at least four times until the maximum loading width is reached.

The feed device can be designed in many ways. Two advantageous types are shown below in principle:
In the first design, the respectively necessary amount of working fluid is already pre-dosed, z. B. in separate bags. To start the cooling effect, a working medium supply line is opened by a working fluid bag to the evaporator, z. B. by piercing the working fluid bag and pressing the working fluid. In this case, only a small opening in the working fluid bag must be stung and provided a supply line for the still liquid working fluid to the evaporator fleece. A further advantageous embodiment of this first design is obtained when the working fluid pouches are inserted outside the evaporator region between the multilayer film. Due to external pressure on the multi-layer film in the area of the working fluid bags, these burst and the liquid working fluid flows to the evaporator fleece. Bursting due to external pressure can be achieved either by the use of a film with a peel effect or by inserting a pointed opener into the working fluid bag. The pointed opener can not press on the film and perforate it within the bulging agent bag during storage time. Only by the action of an additional external force in the area of the opener, the liquid working fluid is displaced and the pointed opener can pierce a small opening in the film. If the tool bags made of a film with peel effect, can be dispensed with separate opener, because the seal seams are due to the peel effect by vigorous pressure on the bag leak and let the contents leak. The physical rupture properties of the peel seal can be specifically adapted to the requirements of the working fluid bag. It must be ensured that the bag does not burst due to the atmospheric pressure applied from the outside, but that the contents are allowed to flow out into the evaporator when the finger pressure is adequately increased. The connecting channel to the evaporator, which can be optimally adapted to the respective geometries present, can keep a narrow strip of flow fabric or flexible plastic hoses open.

In the second type, the entire working fluid can be stored in only one reservoir within the feeding device. The individual subsets must then be divided with other dosing techniques known in principle. The feeding device can be carried out particularly expediently if the filling and emptying valves contained therein are actuated by the already necessary actuation of the pressing means.

In preferred embodiments, the vaporizer may be loaded with the sorbent within a single, all-enveloping, multilayer film. Only when the liquid working fluid flows from the feed device to the evaporator, it can evaporate from there and continue to flow vapor to the sorbent. It is even more advantageous if only a relatively small flow cross-section is required for the liquid working medium. A disadvantage, however, is that the working fluid must sufficiently homogeneously wet the evaporator without being entrained in liquid form in the sorber or even on exiting the opening of the working fluid bag to ice and thus to block the further inflow.

A homogeneous distribution of the working fluid can be achieved according to the invention by a separate, finely branched channel structure, which distributes the working fluid after flowing out of the feed device homogeneously, before it could be entrained liquid by the steam flow. An inexpensive distribution can, for. B. can be achieved by a layer of finely foil, which is arranged around the outlet opening.

A particularly efficient and at the same time cost-effective solution is achieved when the liquid working fluid is homogeneously distributed through the structural material of the steam channel in the evaporator fleece. For this purpose, the working fluid is pressed into the structural material after the feed device has been opened by the overpressure acting from outside on the multilayer film. Here, a part of the working fluid evaporates and tears the still liquid working fluid at high speed. In accordance with the invention shaping of the structural material, the liquid working fluid is deflected several times on the way to the sorbent and thrown repeatedly against the adjacent nonwoven material. This absorbs the liquid components of the working fluid and fixes this against the inflowing agent vapor. In this way, the evaporator fleece is wetted in a very short time homogeneously with the optimum amount of working fluid. The transport of the liquid working fluid is therefore not within the evaporator fleece but via the steam channel within the structural material. Advantageously, the evaporator is flooded from its one end with the liquid working fluid while the pure working medium vapor flows out of the evaporator at the other, far end. The evaporator does not necessarily have to be upright. According to the invention, the feed of the liquid working fluid can also take place from above while the working medium vapor flows out from below. The amount of evaporator fleece is to be adjusted to the volume of the liquid working medium. At the end of the dosing process, the surface of the evaporator fleece, which is in contact with the vessel to be cooled, should be able to absorb and distribute the necessary amount of working medium. But that does not mean that the fleece itself must be distributed homogeneously. In particular, it may be made thinner in the dosing device. Forcibly guided, the entire working fluid flows through this area. This also moisturizes the structural material, the knitted fabric and other fixtures. To ensure even cooling, the fleece can be thinned out at these areas. Consequently, the fleece can also be made thicker at other locations. In particular, where the vessel can deliver more heat by internal, thermal redistribution, this measure increases the cooling rate.

The working medium is distributed and fixed in the fleece by capillary forces or hygroscopic effects. Particularly inexpensive nonwoven materials contain absorbent papers, as they are used in a wide variety for household and industrial for absorbing liquids. Particularly absorbent nonwovens consist of polypropylene microfibers. Equipped with special wetting agents, they can absorb and fix a multiple of their own weight in water.

The manufacturing method for cooling elements according to the invention can proceed as follows. In a pre-sealed tube made of multilayer film, all evaporator components including the feed device are inserted at defined positions. Even before the evacuation, the evaporator area of the geometry of the vessel to be cooled is reshaped. Thereafter, hot sorbent is filled and the cooling element evacuated either in the vacuum chamber or at atmospheric pressure by means of a suction adapter and then sealed.

The sealing of the multi-layer film is usually carried out by pressing hot welding bar on the outer surfaces of the film until the internally superimposed polypropylene layers are liquid and merge together. In addition to thermal contact processes, welding processes using ultrasound have also proven successful. Advantageously, the seal has a width of at least 5 mm even better but of 10 mm. The wider the sealed seam, the lower the leakage rate and consequently the longer the storage time of the cooling element.

The drawing shows in:

1 , Parts of a cooling element in exploded view,

2 , a preformed cooling element when filled with zeolite,

3 , a finished cooling element without pressing means and without thermal insulation,

4 , a thermal insulation with a pressing means,

5 , a cooling element together with insulation and pressing means in a sectional view,

6 , further feeding device with metering chamber and valves,

7 , actuated valves of a feed device after 6 ,

In 1 the main vacuum components of a cooling element are shown. The cooling element is made of a film tube of two multilayer films 1 . 2 envelops. The two multilayer films 1 . 2 can already be cut before sealing according to the drawing. In the area of the evaporator 3 be a cover plate 4 , a structural material 5 to keep the steam flow channel free and a knitted fabric 6 made of PET fibers for smoothing a fleece 7 inserted. The two multilayer films 1 . 2 come to lie each with their PP-sealing layer to each other. By means of not drawn, Hot sealing tools will guide them along the two textured side seams 14 sealed. Along the side seams 14 are four compensation surfaces 13 formed during deformation of the evaporator 3 can absorb wrinkles. The two narrow sides of the multilayer films 1 . 2 stay unsealed first. In the right side opening are eight water bags 8th along with a flow channel 9 introduced. The water bags 8th are made of a peel film and filled with the working fluid water. By manual pressure on the water bags 8th can burst one of the four sealing seams and the water content can be squeezed out because of the external atmospheric pressure. About the flow channel 9 the water content becomes a knitted fabric 6 forwarded and in the area of the evaporator 3 from the fleece 7 distributed homogeneously. Through the left side opening can after deforming the evaporator 3 the hot zeolite filling 10 be filled.

2 shows the loop-like deformation of the evaporator 3 over a cylindrical mold 12 , which has the diameter of the vessels to be cooled later. Because the evaporator 3 before deformation, the non-visible components (cover plate 4 , Structural material 5 , Knitted fabric 6 and fleece 7 ) is the radius of the outer multilayer film 2 about 3 mm larger than the radius of the internal multilayer film 1 , Because the multilayer films 1 . 2 are not stretchable, the forced deformation inevitably leads to wrinkles in the inner radius. In order to prevent the resulting poorer heat transfer, the wrinkles in the area of the four compensation surfaces 13 postponed. The contact surfaces to the vessels thus remain completely wrinkle-free. By means not shown holding tools, the cooling element 20 fixed in the drawn form and position. About the front side opening were the eight water bags including flow channel 9 so inserted that the flow tissue 9 flush with the knitwear 6 docks. About the rear side opening then 750 g, 180 ° C hot zeolite material of the type 13X via a funnel 15 filled. The rear side opening is then also sealed while the front side opening still remains open. The hot zeolite material is then molded and fixed into the desired geometry within the multilayer films by means of hot, externally pressed dies (not shown). In the immediately subsequent manufacturing step, the entire cooling element 20 spent together with the above-described forming and holding tools in a vacuum chamber and evacuated several minutes to a pressure below 6 mbar (abs.). Even in the vacuum chamber then the last still open side opening is behind the water bags 8th sealed.

After removal from the vacuum chamber, the four compensation surfaces 13 folded outwards in the area of the evaporator rim. The finished, evacuated cooling element 20 now has a form according to 3 , The evaporator 3 is after removal of the mold 12 formed into a flexible, laterally open, cylindrical shell. At both ends is the evaporator 3 open and can easily accommodate the vessels to be cooled. The folds are located in the folded compensation surfaces 13 along the cylinder outer shape. The hot zeolite material 10 (not visible) is a space-saving zeolite block 19 shaped and stands with the evaporator 13 over the entire width of the evaporator 3 fluidically connected. The eight water bags 8th form together with the flow channel 9 the metering element. It is housed in the upwardly protruding hose end easily accessible.

To achieve optimum cooling effect, the cooling element must 20 be pressed by means of pressing well on the outer surface of the vessels to be cooled. 4 shows a suitable pressing means 27 in conjunction with a thermal insulation 26 , To a sealable film 21 are tabs on two opposite sides 22 sealed, in which two bars 23 can be threaded. The two parallel bars 23 are at one end by means of a wire 24 connected at a distance of a few millimeters. The thermal insulation 26 consists of an initially plan, about 7 mm thick plate of Styrofoam, which is on the flat film 21 is glued on. If you roll this arrangement then over a form cylinder arises in 4 illustrated pressing means 27 including thermal insulation 26 , About a lever mechanism 33 can the insulation 26 by means of the bars 23 on the evaporator 3 be pressed. After loosening the lever mechanism 33 can be easily removed after cooling the vessel again. The lower bar 23 is in a hole of a disk 31 pressed while the upper bar 23 in a sickle-shaped curved slot 32 to be led. In the picture is the disc 31 positioned horizontally so that the two rods 23 pressed tightly together. Will the disc 31 around the lower bar 23 turned in a vertical position (arrow A) runs the upper bar 23 inside the slot 32 in the direction of arrow B upwards. The pressing force on the evaporator 3 is solved in this position. The vessels to be cooled can be easily inserted and removed in this position. To activate the pressing force, only the disc must 31 be swung back to the left.

5 shows one with pressing means 27 Completed cooling element 20 in a cutaway view. The vessel to be cooled 30 , a commercial soda can, lies on the side, the gas bubble 35 of Drink is located above. The evaporator 3 is from the insulation 26 that from the slide 21 surrounded by the two rods 23 large area on the coat of the vessel 30 pressed. The bars 23 while pressing forceps at the same time on the vapor discharge to the zeolite block 19 and the supply line from the water bags 8th , water bag 8th , Flow channel 9 , Zeolite material 10 and all internal evaporator components are of the multilayer films 1 . 2 enclosed. Because the water bags 8th are inserted at a distance, it is possible, the entire feed device ( 40 ) to save space and in the space between pressing means 27 and zeolite block 19 store. To trigger the cooling function, the feed device 40 be unfolded. To the water vapor without large pressure drop in the zeolite material 10 (only partially drawn) initiate and distribute optimally within this, are the structural material 5 and the cover plate 4 cut so long that they go far into the zeolite material 10 pass. The knitwear 6 and the fleece 7 However, they are cut so short that the liquid water can not flow into the connection channel. At the other end of the evaporator 3 towers the fabric 6 slightly beyond the evaporator surface towards the water bag 8th , This achieves a more even distribution of the from the water bags 8th over the flow tissue 9 inflowing water content.

For cooling the vessel 30 This is first in the relaxed evaporator 3 pushed and with the pressing means 27 on the evaporator 3 pressed. By external pressure on one of the water bags 8th opens a sealed seam and the outer atmospheric pressure presses the bag contents through the flow channel 9 in the evaporator 3 , The dry fleece 7 distributes the liquid water homogeneously. Because of the low system pressure, the water evaporates in the fleece 7 and cools the vessel through the multilayer film 30 ,

6 shows an alternative feeding device 40 at the confluence with the evaporator 3 , In the drawing, the upper multilayer film 2 , the rod 23 and the foil of a foil bag 41 shown transparent. Instead of individual water bag is in this embodiment, a large film bag 41 filled with the total amount of water. Inside the foil bag 41 is a pressure-stable dosing volume 42 housed for a single dosage of 14 ml. The dosing volume 42 has an access 43 inside the foil bag 41 and a spout 44 outside the foil bag 41 , Access 43 is with a flexible, thick-walled silicone hose 48 provided inside the foil bag 41 flows and is open, unless it is squeezed by additional, external forces. Water from the foil bag 41 is thus always when the access 43 is open, due to the upcoming atmospheric pressure from the foil bag 41 in the dosing volume 42 pressed. To the outlet 44 is a spout 45 molded with the foil of the foil bag 42 sealed gas-tight. At the outer end of the spout 45 is on a pipe socket 49 also a silicone hose 46 deferred, but its second end, unlike access 43 , with a tight-fitting, cylindrical plug 47 is closed. The feeding device 40 is thus a separate item that can be bottled and stored separately. In the design case, for a zeolite filling of 750 g, at least 112 g of water are in the foil bag 41 filled in gas-free. The two silicone tubes 46 . 48 are so to the knit 6 of the evaporator 3 put on that the rods 23 of the pressing agent 27 across the ends of the silicone tubing 46 . 48 to come to rest. How out 7 visible (sectional view along the bars 23 ), squeeze the two bars 23 in the pressed state on the two ends of the silicone tubes 46 . 48 , The silicone tube 48 it is closed, the silicone tube 46 opens by external pressure two small column 50 between the stopper 47 and the inner wall of the silicone tube 46 , Through the column 50 the water filling can be pushed by its own vapor pressure from the dosing volume 42 into the knitwear 6 leak. Only when the bars 23 be released again (arrow C), the additional pressing force disappears onto the silicone hoses 46 . 48 , The spout 44 closes first and access 43 opens shortly afterwards. Thus, the dosing volume 42 automatically filled again, without water in the evaporator 3 to let flow out. Once the bars 23 be pressed again, the dosed amount of water for the next cooling is available again.

8th finally shows the cooling curve of a 250 ml beverage can with an initial temperature of 31 ° C (thick curve 1). At the start time (minute 2), a water bag with 14 ml content is squeezed out. Within a few seconds, the first temperature in the evaporator (curve 2) drops to approx. 7 ° C. As soon as the water entering the evaporator has reached the second measuring point (curve 3), its temperature also drops. There are three measuring points in the zeolite material. Again, a time delay is apparent. First, the measuring point 5 reached by the incoming steam, after 3 minutes measuring point 4 and it is not until the end of the cooling time that the furthest zeolite material becomes warm (curve 6). The very shallow rise of this measuring point shows the expert that in this cooling element more than the minimum amount of zeolite necessary for 4 vessels is filled. With a precisely measured, minimum amount, this measuring point would also be very hot. After about 12 minutes, the beverage can is cooled from 31 ° C to below 7 ° C. The late rise of the two evaporator temperatures (curves 2 and 3) shows that the Water supply is consumed at these locations. The cooled beverage can can then be removed after releasing the pressing means and replaced by a warm can.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0368111 [0003]
• DE 3425419 [0003]
• WO 01/10738 A1 [0004]
• EP 01902261 [0005]
• US 5197302 [0005]
• WO 2007/006065 [0005]
• US 6474100 B1 [0007]
• EP 08008007 [0008]

Claims (14)

Cooling element ( 20 ) for cooling a vessel ( 30 ) with a filling amount of sorbent ( 10 ) which is capable of sorbing, under vacuum, a vaporous working fluid which is of a liquid working fluid quantity in an evaporator ( 3 ) evaporates and with a feed device ( 40 ), which at the beginning of each cooling process, a portioned amount of working fluid to flow into the evaporator, characterized in that the feed device ( 40 ) in each cooling process in the evaporator ( 3 ) inflowing working fluid to a maximum of one quarter of the sorbent ( 10 ) at T = 50 ° C and p = 6 mbar limit the maximum amount of working fluid that can be absorbed and that in the cooling element ( 20 ) existing working fluid allows at least four consecutive cooling operations and that the evaporator ( 3 ) for heat absorption from dockable vessels ( 30 ) is equipped with a flexible heat exchanger surface, which by means of releasable pressing means ( 27 ) on the successively docked vessels ( 30 ) can be pressed. Cooling element ( 20 ) according to claim 1, characterized in that the adsorbed at the respectively absorbed agent portion in the sorbent ( 10 ) released heat of adsorption predominantly as sensible heat (temperature increase) in the sorbent ( 10 ) is buffered. Cooling element ( 20 ) according to one of the preceding claims, characterized in that the vacuum-tight envelope of the cooling element ( 20 ) predominantly of multilayer film ( 1 . 2 ) and that the evaporator ( 3 ) is flexible in order, by means of pressing means ( 27 ) has good thermal conductivity on the vessels ( 30 ) can be pressed. Cooling element ( 20 ) according to one of the preceding claims, characterized in that on the multilayer film ( 1 . 2 ) in the area of the evaporator ( 3 ) Compensation surfaces ( 13 ) are provided, which can compensate for differences in length during deformation by wrinkling. Cooling element ( 20 ) according to one of the preceding claims, characterized in that the sorbent ( 10 ) synthetic and / or natural zeolite and that the working fluid contains water. Cooling element ( 20 ) according to one of the preceding claims, characterized in that at least the evaporator ( 3 ) and / or the vessel ( 30 ) with a flexible insulation ( 26 ) and that the flexible insulation ( 26 ) at least part of the pressing means ( 27 ) outgoing pressing forces on the evaporator ( 3 ) transmits. Cooling element ( 20 ) according to any one of the preceding claims, characterized in that the working medium in at least four separate water bags ( 8th ), which by manual pressure, the working medium for evaporation in the evaporator ( 3 ). Cooling element ( 20 ) according to one of the preceding claims, characterized in that the feed device ( 40 ) a metering volume ( 42 ), from which by opening an outlet ( 44 ) the metered amount of working fluid in the evaporator ( 3 ) and access ( 43 ), via which working medium from a foil bag ( 41 ) into the dosing volume ( 42 ) and that the access ( 43 ) and the spout ( 44 ) can not be opened at the same time. Cooling element ( 20 ) according to claim 8, characterized in that the outlet ( 44 ) and / or access ( 43 ) from the outside onto the multilayer film ( 1 . 2 ) applied forces can be opened or closed. Cooling element ( 20 ) according to claim 9, characterized in that the outlet ( 44 ) with the application of the pressing agent ( 27 ) can be opened. Cooling element ( 20 ) according to one of the preceding claims, characterized in that the multilayer film ( 1 . 2 ) is sealed to a film tube in the middle of the evaporator ( 3 ) and at one end of the hose the feeding device ( 40 ) and in the other end of the tube the sorbent ( 10 ) contains. Cooling element ( 20 ) according to one of the preceding claims, characterized in that the evaporator ( 3 ) a fleece ( 7 ) for the planar distribution of the liquid working medium and a structural material ( 5 ) for the forwarding of the fleece ( 7 ) vaporizing agent vapor to the sorbent ( 10 ) and that by the structural material ( 6 ) stretched flow cross-section is small enough to freeze the working fluid in the fleece ( 7 ) to prevent. Cooling element according to one of the preceding claims, characterized in that the pressing means ( 27 ) on the flexible insulation ( 26 ) and thereby the evaporator ( 3 ) over the entire surface of the vessel ( 30 ) presses. Method for producing a cooling element ( 20 ) according to one of the preceding claims, characterized in that at least 150 ° C hot sorbent ( 10 ) in the cooling element ( 20 ) and that the finished molded cooling element ( 20 ) is evacuated to an absolute pressure of less than 6 mbar until the sorbent ( 10 ) Evaporating working fluid displaces residual gases and only working agent vapor in the internal volume of the cooling element ( 20 ) is included.

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