The present invention relates to a pouch filled with phase-change material and method for manufacturing a pouch filled with phase-change material. The present invention further relates to crockery provided with a pouch filled with phase-change material.
The use of phase-change material as heat storage material, wherein the phase-change material is able to absorb heat in a relatively short time and to relinquish this heat again over a longer period of time, is known. An example of such an application is the use of phase-change material in a a plate on which hot food is served. By making use of phase-change material the plate will cool less quickly and the food will remain warm for longer. A cavity filled with phase-change material is typically provided in the plate.
Typically phase-change materials used for this and similar applications are solid at room temperature and transpose to a liquid phase at higher temperatures at which they absorb heat. When the phase-change material is in the liquid phase, there is the danger that particles of the phase-change material can escape through the micropores of the plate. In the liquid phase the phase-change material can moreover move freely in the cavity under the influence of movements of the plate, whereby the release of heat to the plate will decrease and whereby an irregular and/or varying distribution of weight of phase-change material will occur in the plate.
Embodiments of the invention have the object of providing phase-change material in a manner such that a better absorption and release of heat is obtained compared to known applications of phase-change material as heat storage material.
A first aspect of the invention relates to a pouch filled with phase-change material, wherein the pouch comprises a preformed first wall and second wall. The first wall comprises a bowl-shaped part, in which the phase-change material is accommodated, and a peripheral part, wherein the second wall is attached to the peripheral part of the first wall. A high vacuum prevails in the pouch, and the pouch is intended for placing against a wall to be heated or cooled.
By providing the phase-change material in a filled pouch the freedom of movement of the phase-change material is limited by the pouch. Because a high vacuum prevails in the pouch, wherein a pressure of between 1×10−1 and 1×10−7 Pa typically prevails in the pouch, thermally insulating air is prevented from being able to lodge between the phase-change material and the walls of the pouch, or between different parts of the phase-change material. The phase-change material in the vacuum pouch is moreover protected from possible contaminants, protected against possible degradation of the phase-change material, and igniting of the phase-change material is avoided by the vacuum pouch. The high vacuum in the pouch can be achieved by providing a preformed first wall of the pouch with a bowl-shaped part and a peripheral part, so that the phase-change material can be placed in the bowl-shaped part, wherein the second wall is attached to the peripheral part of the first wall immediately after vacuum has been drawn in the pouch. The advantage of the preformed first wall with bowl-shaped part is that vacuum can be drawn in simple manner in the pouch and that a higher vacuum can be achieved when compared to the use of phase-change material between two flat walls. The first wall and second wall of the pouch can be attached to each other in different ways at the peripheral part of the first wall, such as by means of welding, glueing and so on.
In a preferred embodiment the pouch is elastic and flexible to an extent such that the pouch can also stretch when the phase-change material expands during transition from the one phase to the other, and such that the pouch becomes taut again when the phase-change material contracts during a reverse phase transition. In combination with the high vacuum in the pouch, the flexibility of the pouch provides for the largest and most efficient possible contact surface between the phase-change material in the pouch and the wall to be heated or cooled without the phase-change material being able to escape or move away from the wall. In a possible embodiment the walls of the pouch are not elastic, and the wall of the pouch remote from the wall to be heated or cooled has a surface area such that an expansion of the phase-change material is possible.
In a preferred embodiment of the pouch filled with phase-change material the first wall and the second wall are at least 40 μm thick, preferably between 50 μm and 150 μm thick. Walls of such thickness ensure that the pouch provides a high degree of protection and strength. Such wall thicknesses moreover allow preforming of the first and/or second wall of the pouch, and allow a bowl-shaped part to be provided in the first wall in which the phase-change material can be placed. It will be apparent to the skilled person that the first and second walls can have mutually differing thicknesses. The second wall in particular is preferably not too thick in order to guarantee a good heat transfer to the part to be heated or cooled.
In an exemplary embodiment of the pouch filled with phase-change material the first wall is a first film and the second wall is a second film. The first film and second film can have the same thickness, but can also have mutually differing thicknesses. Films have the advantage that they can be laminated in advantageous manner, whereby different material properties can be combined in one film. The bowl-shaped part in the first wall is preferably formed in the case of a film by thermoforming.
In an exemplary embodiment of the pouch filled with phase-change material the first wall and the second wall comprise a plurality of layers. The first wall and second wall can comprise the same layers, although the first and second walls can also comprise mutually differing layers. Depending on the intended use of the pouch, it may be useful for the material properties of the first wall to differ from the material properties of the second wall. It may thus be advantageous for instance to provide the wall of the pouch not intended for placing against the wall to be heated or cooled, and which is therefore remote from the wall to be heated or cooled, with an additional thermally insulating layer.
In a preferred embodiment of the pouch filled with phase-change material the first wall and the second wall comprise a welding layer and a barrier layer, wherein the welding layer of the first wall is welded to the welding layer of the second wall.
The barrier layer is selected such that it does not allow passage of molecules of the phase-change material, particularly at higher temperatures at which the phase-change material becomes liquid. The welding layer is selected such that it is weldable in simple manner, whereby the first wall and second wall can be welded to each other at the peripheral part of the first wall.
In an exemplary embodiment the welding layer comprises polypropylene and the barrier layer comprises polyamide.
In an exemplary embodiment of the pouch filled with phase-change material the first wall and/or second wall comprises a layer manufactured from aluminium.
In an exemplary embodiment of the flexible pouch filled with phase-change material the first wall and/or the second wall are injection-moulded pieces or part of one injection-moulded piece. These can for instance be manufactured from silicone.
In a preferred embodiment the pouch is intended for placing with the second wall against the wall to be heated or cooled, wherein the first wall has better thermally insulating properties than the second wall.
When the second wall is placed against the wall to be heated or cooled, it is advantageous that the second wall interferes as little as possible with the absorption and release of heat by the phase-change material, and so facilitates the exchange of heat as well as possible. Conversely, it is advantageous that the first wall, which is not located against the wall to be heated or cooled, allows the least possible loss of heat from the direction of the wall to be heated or cooled, and so is thermally insulated as well as possible.
In a preferred embodiment the pouch is filled with phase-change material not accommodated in capsules.
The use of phase-change material accommodated in micro- or macro-capsules is known. A higher heat capacity can however be obtained by making use of phase-change material not accommodated in capsules when compared to the same amount of material accommodate in capsules. This is because air is often present between the capsules, and this results in a thermally insulating effect. Phase-change material not accommodated in capsules can moreover be placed in simple manner in a pouch of appropriate form, whereby a more efficient contact surface can be obtained for heat exchange when compared to phase-change material accommodated in capsules.
In an exemplary embodiment of the pouch filled with phase-change material the second wall is a preformed wall. The second wall can for instance be adapted in advantageous manner to a shape of the wall to be heated or cooled, whereby the second wall can be placed in efficient manner against the wall to be heated or cooled. In the case of a coffee or tea cup the pouch with a preformed second wall can advantageously be arranged simultaneously against a bottom part of a part to be heated and against an upright side part of the part to be heated. It will be apparent to the skilled person that the same principle can be applied for any random shape of the wall to be heated or cooled, wherein the pouch has a preformed second wall with a corresponding shape in order to guarantee good contact between the second wall of the pouch and the wall to be heated or cooled.
The measures and advantages associated with the above described embodiments of the pouch filled with phase-change material according to the first aspect of the invention are likewise applicable to a piece of crockery provided with a flexible pouch filled with phase-change material and to a method for manufacturing a pouch filled with phase-change material in accordance with respectively a second and third aspect of the invention as described below.
Provided according to a second aspect of the invention is a piece of crockery which is provided with the pouch according to any of the above described embodiments, wherein the pouch is situated in the crockery and wherein the pouch is placed against a part of the crockery to be heated or cooled. The second wall is preferably arranged here against the part of the crockery to be heated or cooled, preferably crockery of ceramic material such as earthenware, chinaware or glass. In the case of a plate this plate can take a double-walled form with an upper wall to be heated or cooled, and a lower wall. The pouch is then preferably arranged between the lower wall and the upper wall, wherein the second wall is arranged against the upper wall to be heated or cooled, while the first wall is located at a distance from the lower wall such that it is not heated, or hardly so.
A third aspect of the invention relates to a method for manufacturing a pouch filled with phase-change material, wherein the method comprises of:
Providing the first wall with a bowl-shaped part enables easy arrangement of the phase-change material in the bowl-shaped part, wherein the second wall can then be placed as a cover connecting to the first wall. This allows sealing of the whole in simple and reliable manner.
According to an exemplary embodiment of the method for manufacturing a pouch filled with phase-change material, the shaping of the first wall of the pouch comprises of thermally preforming the first wall of the pouch. The first wall can for instance then be a film which is thermally preformed.
In an alternative embodiment the shaping of the first wall of the pouch comprises of preforming the first wall of the pouch in a mould by means of underpressure.
According to an alternative exemplary embodiment, the shaping of the first wall comprises of injection moulding the first wall.
According to a preferred embodiment of the method for manufacturing a pouch filled with phase-change material, attaching the second wall to the peripheral part of the shaped first wall comprises the following steps of:
Providing the first wall with a bowl-shaped part enables the phase-change material to be arranged easily in the bowl-shaped part, wherein the second wall can then be placed as a cover connecting to the first wall. This allows a vacuum to be drawn in simple and reliable manner in the whole entity.
According to an exemplary embodiment, sealing of the pouch at the peripheral part of the first wall comprises of welding or glueing the second wall to the peripheral part of the first wall.
According to an exemplary embodiment, placing of the phase-change material in the bowl-shaped part of the shaped first wall comprises of melting the phase-change material, casting the molten phase-change material in a mould and, after cooling, placing the hardened phase-change material in the bowl-shaped part. This simplifies creation of a vacuum in the space between the first and second walls.
According to an exemplary embodiment, the method for manufacturing a pouch filled with phase-change material comprises of shaping the second wall of the pouch prior to the attachment. The second wall can in this way be given a shape which is adapted to the shape of the part against which the second wall must be placed.
According to an exemplary embodiment, the shaping of the second wall comprises of injection moulding the second wall or thermally preforming the second wall.
In an alternative embodiment the shaping of the second wall of the pouch comprises of preforming the second wall of the pouch in a mould by means of underpressure.
The above stated and other advantageous properties and objectives of the invention will become more apparent, and the invention better understood, on the basis of the following detailed description when read in combination with the accompanying drawings, in which:
A first embodiment of a pouch filled with phase-change material according to the invention is illustrated in
Pouch 100 is preferably filled with phase-change material 130 not accommodated in capsules. Non-encapsulated phase-change materials, or so-called pure phase-change materials, can for instance be obtained by melting phase-change material in granular form to a desire shape. Although the use of phase-change material 130 accommodated in micro- or macro-capsules is known, this is disadvantageous because a thermally insulating air layer may be present between the capsules. By making use of phase-change material 130 not accommodated in capsules, a higher heat capacity can as a result be obtained when compared to the same amount of phase-change material accommodated in capsules. Phase-change material 130 not accommodated in capsules can moreover be placed in simple manner in a suitable form in a pouch, whereby a more efficient contact surface can be obtained for heat exchange between the pouch and the wall to be heated or cooled when compared to phase-change material accommodated in capsules.
Walls 110, 120 of pouch 100 can comprise different materials just as long as the walls 110, 120 can keep the phase-change material 130 contained. The freedom of movement of phase-change material 130 is thus limited by pouch 100. The pouch is preferably elastic and flexible to an extent such that pouch 100 can also stretch when phase-change material 130 expands at the transition from the solid phase to the liquid phase, and such that pouch 100 becomes taut again when phase-change material 130 contracts during a reverse phase change.
In a preferred embodiment of pouch 100 filled with phase-change material 130 the first wall 110 and second wall 120 are at least 40 μm thick, preferably between 50 μm and 150 μm thick. Walls 10, 120 of such thickness ensure that pouch 100 provides a high degree of protection and strength and/or that pouch 100 is sufficiently flexible. Such wall thicknesses moreover allow thermal preforming of first 100 and/or second wall 120 of the pouch and allow a bowl-shaped part 111 to be provided in first wall 110 in which phase-change material 130 can be placed. The first 110 and second wall 120 can have mutually differing thicknesses.
It is noted that
In an exemplary embodiment of pouch 100 filled with phase-change material 130 the first wall 110 is a first film and second wall 120 is a second film. The first film and second film can have the same thickness but can also have mutually differing thicknesses. When first wall 110 is a film, first wall 110 can be preformed by means of thermal preforming such that first wall 110 comprises a bowl-shaped part 111 and peripheral part 112. Films have the advantage that they can be laminated in advantageous manner, whereby different material properties can be combined in one film. Embodiments of the pouch filled with phase-change material 130, wherein the walls or films 110, 120 comprise different layers, will be discussed in more detail with reference to
The preformed first wall 110 and/or second wall 120 of pouch 100 need not be films, but can for instance also be injection-moulded pieces. First wall 110 can for instance be injection moulded in a specific form such that first wall 110 comprises a bowl-shaped part 111 and a peripheral part 112. The first and/or second wall 110, 120 of pouch 100 can thus consist for instance of injection-moulded silicone or other plastics.
In a preferred embodiment of pouch 200 filled with phase-change material 230 the first wall 210 and second wall 210 comprise a welding layer 210b, 220b and a barrier layer 210a, 220a, wherein welding layer 210b of first wall 210 is welded to welding layer 220b of second wall 220. Barrier layer 210a, 220a is selected such that it does not allow passage of molecules of phase-change material 230, particularly at higher temperatures at which phase-change material 230 becomes liquid. Welding layer 210b, 220b is selected such that it is weldable in simple manner, whereby first wall 210 and second wall 220 can be welded to each other at peripheral part 212 of the first wall. A material which is particularly suitable as welding layer 210b, 220b because of its high weldability is polypropylene. A material which is particularly suitable as barrier layer 210a, 220a, because of the low permeability in respect of phase-change material and the high resistance at high temperatures, is polyamide. According to a preferred embodiment, the combined thickness of welding layer 210b, 220b and barrier layer 210a, 220a lies between 60 μm and 100 μm per wall 210, 220. At a thickness within this interval the walls 210, 220 display high resistance to cutting. This is advantageous for instance when pouch 200 is used in a piece of crockery, such as a plate, wherein the high resistance to cutting provides protection against for instance fragments of the plate if the plate were to break, and ensures that phase-change material 230 remains intact in pouch 200.
In an exemplary embodiment of pouch 200 filled with phase-change material 230 the first wall 210 and/or second wall 220 comprises a layer manufactured from aluminium. A pouch can for instance thus be formed in advantageous manner which consists of a welding layer, for instance of polypropylene, laminated with an aluminium foil. The aluminium foil ensures that the pouch is substantially impermeable to molecules.
Although
Shaping of the first wall can take place in different ways. According to an exemplary embodiment of the method 600 for manufacturing a pouch filled with phase-change material, step 610 of shaping the first wall of the pouch comprises of thermal preforming of the first wall of the pouch. When the first wall is a film, it can particularly be shaped by means of thermal preforming. The preformed first wall can have different shapes. Depending on the intended use of the pouch, a specific shape can be preferred to another shape. The dimensions can further be adapted to the intended use. An alternative manner of shaping the first wall is by injection moulding of the first wall. A first wall can for instance thus be injection moulded in silicone or other suitable plastic.
According to an exemplary embodiment, step 620 of method 600 comprises of melting the phase-change material, casting the molten phase-change material in a mould and, following cooling, placing the phase-change material in the bowl-shaped part, for instance phase-change material which has hardened in the form of a disc. First melting for instance granulates of phase-change material enables the phase-change material to be brought into a desired shape by casting the molten phase-change material in a mould as desired. Following cooling, the shaped phase-change material can then be placed in the bowl-shaped part of the first wall, and the phase-change material can be packed under high vacuum between the first and second wall of the pouch.
According to a preferred embodiment, step 630 of method 600 comprises the following steps. During a first step the first and second walls are positioned relative to each other such that the second wall can be attached at the peripheral part of the first wall. When the first and second walls are in position for attachment, a vacuum is drawn in the space between the first wall and the second wall and, substantially instantaneously after applying the vacuum, the pouch is sealed at the peripheral part of the first wall. Drawing a vacuum in the space between the first and second walls takes place for instance by providing tubes between the first and second walls, by means of which vacuum is draws in the space. It will however be apparent to the skilled person that alternative ways can be employed to draw a vacuum in the pouch.
The sealing of the pouch at the peripheral part of the first wall can also take place in different ways. According to an embodiment, the pouch is sealed by welding the second wall to the first wall at the peripheral part of the first wall. According to an alternative embodiment, the pouch is sealed by glueing the second wall to the first wall at the peripheral part of the first wall. It will be apparent to the skilled person that other ways can be employed to seal the pouch.
According to an exemplary embodiment, the method 600 for manufacturing a pouch filled with phase-change material comprises of shaping the second wall of the pouch prior to attachment. Shaping of the second wall can take place in different ways. According to an exemplary embodiment, shaping of the second wall of the pouch comprises of thermally preforming the second wall of the pouch. When the second wall is a film, it can particularly be shaped by means of thermal preforming. The preformed second wall can have different shapes. Depending on the intended use of the pouch, a specific shape can be preferred to another shape. An alternative manner of shaping the second wall is by injection moulding the second wall. A second wall can for instance thus be injection moulded in silicone or other suitable plastic.
The skilled person will appreciate that the invention is not limited to the above described embodiments, and that many modifications and variants are possible within the scope of the invention, which is defined solely by the following claims.
Number | Date | Country | Kind |
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2016/5527 | Jun 2016 | BE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/BE2017/000033 | 6/29/2017 | WO | 00 |