ES2266306T3 - CONTAINER FOR FOOD WARMING, EQUIPPED WITH VENTILATION MEDIA. - Google Patents

Abstract

Device (1) for the packaging and preparation of food, (20), provided with a dish-shaped container (4), which is provided at the topside with a take out opening, closed by at least two layers of film (8,10) which are placed above each other, whereby at least the bottom film is provided with perforations (18), whereby means are provided to allow for the escape of vapour during use between the bottom film and a film placed above it.

Description

Food heating container, endowed of ventilation means.

The present invention relates to a device for packaging and food preparation. This type of devices are known from EP document 0971849.

This known device, particularly suitable for use in a microwave oven, comprises a plastic container, closed on the upper side by a laminar material that closes tightly by wrapping the container. A part of said sheet material is made to function as a valve. During the heating of the food inside the container, the vapor pressure increases inside it, rising above the atmospheric pressure. Therefore, the temperature in the container will rise rapidly above 100 ° C, allowing such foods to be prepared quickly, while maintaining their properties. The valve is adjusted so that said steam escapes through it when a certain pressure is reached, thus avoiding pressures and temperatures too much.
high.

This known device has the advantage of that food can be packaged and transported within the same easily, keeping them fresh, and protecting them outside environment and also preventing moisture losses out of the container. In addition, food can be prepared quickly, preserving, for example, aroma, texture and vitamins, while preventing the formation of pressures too high. However, the disadvantage of this device is that a valve should be applied relatively expensive.

In addition, fixing said valve (one or more valves per device) is complex and time consuming, in particular because this procedure must be carried out with great care. After all, when fixing is not accurate, the steam could escape from the valve and / or the valve or the material laminate could be separated preventing proper operation of the device, with all the dangers that this fact entails.

Another disadvantage of this known device is that the valve may become clogged with food, limiting this way the amount of steam that can escape or preventing that escape. An additional disadvantage is that this device must be Opened by the user quickly after the given heating otherwise, the device would be compressed because of the pressure differences During the opening of the container there is the risk of the user coming into contact with hot steam that is still present inside.

EP 0661219 discloses a material multilayer laminating for closing food containers; said multilayer sheet material comprises two layers of sheet material joined together on a large part of its surface which, during use, closes the extraction opening of the container, before closing said container. There are channels of ventilation between said layers of sheet material, in which  have ventilation openings on the edge of the sheet material shaped like valves for manual opening ("rip valves").

EP 0967160 discloses an element laminated with layers, and at least equipped with two layers of sheet material bonded together along most of the surface that extends along the extraction opening of a container

A device has been proposed in which a opening closed by an adhesive laminar element is made in the laminar element instead of a valve.

Said adhesive element must be removed by the user before heating. The disadvantage of this is that I don't know produces a rapid rise in pressure inside the device and the user must first manipulate the device before its utilization.

It is an objective of the present invention to give know a device of the type described above, in which the disadvantages of known devices are avoided at the same long as its advantages are retained. Therefore a device in accordance with the present invention is characterized by provisions of claim 1.

A device in accordance with this invention offers the advantage that the layers of sheet material they can be fixed easily, so that during your utilization excess pressure can be achieved and maintained desired inside the package automatically, for example a pressure between 1.0 and 4.0 bar and preferably between 1.3 and 1.9 bar, as a result of the means arranged to allow the escape of steam.

The steam can only escape when a certain increase in vapor pressure. Since I don't know need valves, the mentioned disadvantages are avoided previously. The laminar elements can be supplied with Simple form in the form of rolls and can be cut to size, which is why it can also be applied easily to several container sizes In addition, this way you can always choose an appropriate combination of laminar elements and containers, for example depending on the food that will be packaged and prepared. Preparation must be understood in this context at least as a preparation for consumption, including heating.

An advantageous embodiment of a device according to the present invention is characterized by provisions of claim 3.

Making at least one laminar element, particularly the upper laminar element, be impermeable to gas and liquid impermeable, the advantage is achieved by which the pressure can increase relatively quickly between the lower laminar element and the laminar element impervious to gases and liquids mentioned above, so it is also achieved a rapid increase in pressure to the desired level within the container.

In an alternative embodiment of the present invention multiple perforated laminar elements are arranged, whereby in the direction away from the lower layer, the laminar element or each laminar element positioned thereon has perforations with a total permeable surface that is less than the laminar element
lower.

In a particularly advantageous embodiment, a device according to the present invention is characterized by the provisions of claim 5.

In said device the steam, trapped between The two laminar elements, can escape because the second laminar element is loosened, at least partially, when the pressure between said laminar elements exceeds a certain increased pressure Said device can be manufactured in a manner particularly simple, at the same time that an action is achieved automatic immediately, in which overpressures allowed can be adjusted simply by choosing of the mentioned connections.

In an alternative embodiment the element laminar or every second laminar element is implemented so that it tears when a certain pressure is exceeded, allowing the release of overpressure.

The use of a closed laminar element, gas and liquid impermeable, on the lower laminar element perforated for a device according to the present invention, offers the advantage that being closed prevents moisture from escape outwards through the perforations, at the same time that is also achieved a tight seal. This implies that, by For example, a modified atmosphere can also be created within the container before or during packaging, for example for preservation of packaged food. The gas in that atmosphere It can only escape when the laminar elements are separated from others at least partially.

It is preferred that the perforations in the lower laminar element are relatively small, for example, round perforations with a diameter between 50 and 5000 µm, preferably between 100 and 750 µm, or openings with a shape different but with a comparable surface. A dimension between 200 and 500 µm is particularly appropriate. Through this one obtains a favorable resistance to the passing flow of steam, by at the same time that these perforations can be manufactured in a way relatively accurate

In a device in accordance with this invention, the lower laminar element is preferably manufactured  from a thermosetting sheet material, particularly a sheet material made from polyester and polypropylene. The lower laminar element or each laminar element arranged on the lower laminar element is preferably a laminar element thermally sealed plastic, particularly polyester, which can be taken off Other sheet materials could still be selected, consisting of one or more layers depending on the application particular selection that will be apparent to technicians in the matter.

The present invention further relates to a method for manufacturing a packaging device and food preparation, characterized by the provisions of the claim 14.

Said method has the advantage that the container or package can be manufactured particularly fast and simple, in which food can be packaged, transported and prepared. In this method they can be supplied several laminar elements arranged one above the other, for example as a laminated material, before joining them with the container, although said laminar elements can be supplied separately from each other. The laminar elements, for example, they can be supplied with roll form and be cut directly to size before or during the operation of positioning In this way a great freedom of design is achieved, so you can easily make packages with great variety of sizes.

The present invention further relates to a food preparation method, characterized by provisions of claim 18.

With this method the advantage is achieved that Packaged foods can be placed directly in an oven, in particular a microwave oven or a steam oven, in which Food can be heated and prepared quickly, without being negatively affected. On the contrary, with a method according to the present invention preserves the quality of food in a particularly favorable way. In In particular, packaged foods are prevented, for example, from being dry or lose texture, color, aroma or characteristics similar, or in any case prevents such qualities from being Affected unwantedly. In addition, in this way they remain the vitamins.

In the attached claims are presented more detailed advantageous embodiments of a device or method in accordance with the present invention.

To clarify the present invention, they will be given examples of embodiments of a device and method according to the present invention in greater detail with reference to following drawings:

Figure 1 is an enlarged schematic view and in perspective of a packaging device according to the present invention;

Figure 2 is a sectional side view cross section of a package or container according to figure 1, in closed state;

Figures 3A-C show the food warming in three consecutive stages for a package according to the present invention;

Figure 4 shows an alternative embodiment in schematic cross-sectional side view of a container of according to the present invention.

Figure 5 schematically shows a detail of an edge of a container with laminar elements; Y

Figure 6 shows a corner of a alternative embodiment of a packaging device according to  The present invention.

Figure 1 shows schematically and with an enlarged perspective view, a packaging device (1) in accordance with the present invention.

Said packaging device (1) comprises a plate-shaped container (4), for example manufactured from of heat-sealable plastic material, known in practice and Suitable for use in a magnetron or steam oven. Said container shaped plate (4) is provided in its part upper with an extraction opening (2), surrounded by an edge plane (6) extending outward. Said device of packaging (1) further comprises a first lower laminar element (8) and a second upper laminar element (10). The term lower should be understood in this context as closer to the extraction opening (2), the upper laminar element as the laminar element or each laminar element on the side that is remote of the extraction opening (2) of the lower laminar element (8). In the embodiment shown, the two laminar elements (8) and (10) they are endowed with a surface size that fits so approximate to the upper side of the container (4), as it is determined by the longitudinal edge (6). The laminar elements (8) and (10) are manufactured from a material that can be fixed by a thermal closure on the longitudinal edge (6). By therefore, the lower laminar element is manufactured preferably from a heat sealable laminate material and thermostable, the upper laminar element (10) from a heat sealable plastic material, preferably a plastic heat sealable that can be detached. Figure 5 shows the laminar elements (8) and (10) on the longitudinal edge (6). He lower element (8) consists for example of a sheet material manufactured from a first layer (14) of polypropylene, by example, with a thickness between 60 and 120 µm, and particularly 90 um, and a second layer (12) of polyester on the layer above, for example, with a thickness between 10 and 15 µm, particularly 12 µm. Therefore, the laminar element upper (10) is manufactured, for example, from polyester with a thickness of about 25 µm, preferably polyester 20 µm heat sealable that can be torn off. The materials and  dimensions mentioned in this document are presented to as an example and should not be taken as a limitation in terms of Field of the present invention.

As shown in figure 1, the element lower laminar (8) is equipped with a perforation pattern (16), in the embodiment shown is a quantity of perforations (18) with Mainly circular cross section. Such perforations they have, for example, a diameter between 50 µm and 5000 µm, particularly between 200 µm and 500 µm, so that the water droplets, or in any case steam, can pass through thereof when there is sufficient pressure inside the container (4), as will be described in greater detail herein document.

During use, an amount of food (20), as shown for example in figure 2, in the plate-shaped container (4), after which it is fixed around you the first lower laminar element (8) with the help of first sealing means (22) at the longitudinal edge (6). The first sealing means (22) are represented schematically by shading. It will be clear that Any type of sealing method can be applied to carry out the fixation of the first lower laminar element (8) at the longitudinal edge (6), or in any case to the container (4). In the embodiment shown in Figure 2, the second element Laminar (10) is fixed to the lower laminar element (8) with the support of second sealing means (24), in the embodiment shown directly on the first sealing means (22) and the longitudinal edge (6). The first means of closure waterproof (22) and the second sealing means (24) are chosen so that the lower laminar element (8) is joined relatively tightly with the longitudinal edge (6). That connection, formed by the first sealing means (22), is stronger than the connection between the lower laminar element (8) and the second laminar element (10), formed by the second means Watertight closure (24). The purpose of this will be described more later in this document. It will be clear that in the drawings the thickness of the laminar elements (8) and (10), the first and second sealing means (22) and (24) and the Plate-shaped container (4) are not shown to scale.

When food (20) is packaged from the way shown in figure 2 on the packaging device (1), then they can be transported and stored within said device, at the same time as the package (1) with food (20) can be placed in a closed state inside an oven of microwave (magnetron) or inside a steam oven or other Similary. When the oven is turned on, food (20) can be prepared by a method according to the present invention, explained in greater detail by referring to the figures 3A-C. The term preparation should be understood in this context comprising at least the preparation for consumption, including heating.

Figure 3A schematically shows the package (1) according to the present invention being relatively cold In the interior space of the shaped container of plate (4) there is a relatively low temperature T_ {for example room temperature or a lower temperature) and there is a relatively low pressure P0, comparable for example with the atmospheric pressure P_ {A} outside the container (4). Possibly there is a shielding gas inside the container space (4) to get a modified atmosphere. In such cases the Foods (20) are better protected with said gas.

After the oven is turned on, the foods (20) are heated and the humidity present in said food (20) together with possible added moisture is heated and evaporated For this reason, the pressure inside the container (4) is will raise up to a relatively high pressure P1, and therefore the temperature will also increase to a temperature value relatively high T1. As a result of said increase in pressure, the steam will be forced through the openings (18), such as shown with the arrows (25). This steam will flow between the lower laminar element (8) and the upper laminar element (10), but there will be no escape because of the second means of waterproof closure (24). Therefore, the pressure will increase between the lower laminar element (8) and upper laminar element (10) up to a relatively high pressure P2, and consequently the temperature will also increase to temperature T2. When the pressure P2 exceeds a limit pressure, in any case a part of the second sealing means (24) will break,  as shown in figure 3C, allowing steam flow between the lower laminar element (8) and the laminar element superior (10) towards the surroundings, thus balancing the pressure to about atmospheric pressure P A. By therefore the space inside the container (4) below the lower laminar element (8) will expand, while the pressure will will balance up to a maximum pressure P_ {3}, while the temperature will rise to a relatively high temperature T_ {3}. Said T 3 will be for example greater than 100 ° C in views of the relatively high vapor pressure P3. This means that food (20) will be relatively heated fast, so that food quality will be preserved, particularly they will not dry out, and / or they will not lose texture, color or they will undergo flavor changes, at the same time as For example, vitamins will be preserved particularly appropriate. Since the second tight seal is broken automatic, in any case partially, when the pressure P2 between the layers of laminar elements (8) and (10), is automatically adjusts the desired pressure, depending on example of heating, of the amount of steam produced, the inner volume of the container (4) below the element lower laminar (8) and of the total permeable surface of the permeability openings (18) present in the laminar element lower (8).

An embodiment is shown in Figure 4 alternative of a device (1) in accordance with the present invention, in which the lower laminar element (8) and the element upper laminar (10) are fixed with the help of the first means airtight closure (22) and the second sealing means (24), respectively, directly on the longitudinal edge (6). Advantageously, a good connection is achieved between the second laminar element (10) and the rest of the container (4), also when the upper layer of the lower laminar element (8) does not have, or in In any case, the thermal closing capacity is low, or not allows a weak connection appropriately.

In a further alternative embodiment, such as shown in figure 6, the upper laminar element (10) and the lower laminar element (8) is directly fixed one on the other, the lower laminar element (8) being fixed directly on the longitudinal edge (6). There is a line of weakening (26) in the upper laminar element (10), which It is initially closed. When package (4) with food (20) is placed in an oven and is heated, steam flows between the first and second laminar elements (8) and (10) of the mode shown in figures 3A and B, the volume increases between laminar elements and a pressure P2 is created. The line of breakage or weakening (26) will open when the pressure limit P_ {2} and the steam can escape towards surroundings. In this embodiment the lower laminar element (8) and the upper laminar element (10) can remain connected between if and when opening the packaging device (1) they can be torn off and discarded together.

In the exemplary embodiment shown, use a basically rectangular container (4). But nevertheless, the use of a container may be preferred, for example, with an oval or round shape, with which a more uniform warming while developing a heating distribution and one more vapor pressure uniforms

This description is based on a container shaped container since it is known in the art. Said container shaped plate is manufactured, for example, to from plastic or cardboard laminated with plastic, manufactured by example, by vacuum formation, injection molding or Similar techniques In the examples of the embodiments shown, a plate-shaped container is used, manufactured from a material that can be sealed tightly within itself same, used sealing methods known in the art, particularly heat sealing methods. Such materials that They can be used are well known in the art.

The present invention is not limited in any way. mode by the embodiments shown in the description and the drawings. Numerous variations can be carried out within the scope of it, as defined by the claims. Therefore, the perforations (16) and (18) can be arranged in another way, for example forming a matrix regular or irregular openings (18). The quantity and size of the perforations can be selected easily, depending on the products that will be heated, the surfaces, the contents of the container and similar parameters. Bliss Selection will be apparent to those skilled in the art. More than two laminar elements can also be arranged, for example, two laminar elements perforated one above the other, possibly covered by a closed laminar element, in which preferably the perforations of the intermediate laminar element they have a completely permeable surface that is smaller than that of the perforations of the lower laminar element, or in any case they have a resistance to steam flow that is greater than that of lower laminar element. In this way, the pressure can increase Stepwise. In addition, a container that is divided into several compartments, in which at least the lower laminar element is also fixed to a wall of separation of the various compartments. In a particular way, the perforations in the lower laminar element can be different for each compartment to achieve different pressures and / or temperatures in said compartments. Any material appropriate can be applied inside a packaging device in accordance with the present invention. At least one of the laminar elements can also be attached to another container way instead of the heat sealing technique, for example by the application of any suitable sizing technique, of welding or similar. The upper laminar element can also be implemented so that it tears open when a certain maximum pressure, to allow steam to escape.

In an alternative embodiment that is not waterproof to the gas of the device according to the present invention they have multiple perforated layers of sheet material, by which, in the direction away from the laminar element bottom, any laminar element placed on it is equipped with perforations with a completely permeable surface which is smaller than that of the lower laminar element.

Said perforations in the previous element Laminar placed are, for example, round and have a diameter between 10 and 1000 µm, preferably between 20 and 100 µm and particularly they have a diameter between 20 and 60 µm. These perforations are made with a frequency of, for example, 10 to 1000 perorations per m2.

The objective of this alternative embodiment is increase the shelf life of food products packaged in the device, particularly the plant material. Said set of perforated layers of sheet material allow adjust the O2 and CO2 levels during transport and storage.

This and many other comparable variants remain within the scope of the present invention as defined by the appended claims.

Claims (19)

1. Device (1) for food packaging and preparation (20), equipped with a plate-shaped container (4), which is provided on the upper side by an extraction opening, closed at least by two layers of material laminar that are placed one on top of the other, in which at least the lower laminar element (8) is provided with perforations (18) arranged for steam escape during use between the lower laminar element (8) and the laminar element ( 10) placed thereon, characterized in that said lower laminar element (8) and said laminar element (10) disposed thereon are connected to each other and / or to the container (4) by tight seals (22, 24) exclusively at the circumferential edge (6) of the extraction opening (2) of the container (4) whereby essentially at least two layers of the laminar elements (8, 10) remain separated from each other along the entire surface of the extraction opening (2) of the container (4), so that during use when the pressure between said two laminar elements (8, 10) exceeds an upper limit by at least a part of the seal that connects the upper laminar element with said edge, it breaks and / or said upper laminar element (10) is torn to allow steam to escape between said laminar elements (8, 10). 2. Device according to claim 1, in the that the laminar elements (8, 10) composed of at least two layers are sealed tightly over the longitudinal edge of the container (4). 3. Device according to claim 1 or 2, in which at least one of the laminar elements is sealed to Gases and liquids. 4. Device, according to any of the preceding claims, wherein at least one element laminar (10) placed on the lower laminar element (8) comprises perforations (18) with a total permeable surface that is less than the permeable surface of the perforations of the lower laminar element (8). 5. Device, according to any of the preceding claims, wherein the lower web  (8) is connected to the container (4) and the laminar element or second laminar element (10) is connected to the element lower laminate (8), preferably along the edge longitudinal thereof, whereby the connection between the element bottom (8) and the container (4) is stronger than the connection between the lower laminar element (8) and the second element laminate (10) to allow the formation of the means that allow escape said steam so that the gas can flow through the perforations (18) in the lower laminar element (8), and between the lower laminar element (8) and the second laminar element (10) during the formation of the pressure inside the container (4) and the connection between the second sheet element (10) and the element lower laminar (8) will break at least partially, so which conserves the connection between the container between the container (4) and the lower laminar element (8). 6. Device, according to any of the claims 1 to 5, wherein the lower laminar element (8) is connected to the container (4) and the laminar element or a second laminar element (10) is connected to the element lower laminate (8), preferably along the edge longitudinal thereof, in which the connection between the element lower laminar (8) and container (4), the connection between the lower laminar element (8) and the second laminar element (10) and the layer of laminar elements, is selected so that the gas can flow through the perforations (18) of the web lower (8) between the lower laminar element (8) and the second laminar element (10) during the increase in pressure within the container (4) and the connection between the second laminar element (10) and the lower laminar element (8) will break at least in a way partial and / or an opening in the second laminar element (10) is will form to allow the escape of the mentioned steam to relieve the pressure between the laminar elements, so that the connection between the container (4) and the lower laminar element (8) remains intact 7. Device, according to any of the preceding claims, wherein the perforations (18) in the lower laminar element (8) has a diameter between 50 µm and 5000 µm, preferably between 100 µm and 750 µm, and particularly between 200 µm and 500 µm. 8. Device, according to any of the preceding claims, wherein the lower web  (8) is formed from a thermoset laminated material, particularly a polyester laminate material and Polypropylene. 9. Device, according to any of the preceding claims, wherein any laminar element (8) placed at the bottom is heat sealable, preferably a heat-sealable plastic sheet element that can be torn off, particularly a polyester. 10. Device, according to any of the claims 1 to 9, wherein multiple layers are arranged perforated sheet material (8, 10), in which at least one laminar element (10) which is placed on said laminar element bottom (8) contains perforations (18) with a surface fully permeable that is smaller than the surface completely permeable of the perforations of the lower laminar element. 11. Device, according to any of the claims 1 to 10, wherein multiple layers are arranged perforated sheet material (8, 10), in which at least one laminar element (10) is placed on the laminar element bottom (8) containing perforations with a diameter between 10 - 1000 µm, preferably between 20-100 µm and particularly a diameter between 40-60 µm. 12. Device, according to any of the claims 1 to 11, wherein multiple layers are arranged perforated sheet material (8, 10), in which at least one of the laminar elements (10) that is placed on the element lower laminar (8) contains perforations with a density of 10 to 1000 perforations per m2. 13. Device, according to any of the claims 1 to 12, wherein a container is used which is  divided into several compartments, in which at least the lower laminar element (8) is also fixed to the wall of Separation of the different compartments. 14. Method for the production of a device for food packaging and preparation, in which a container (4) is filled with a portion of food (20), after which the container (4) is sealed tightly to gases and liquids mainly at least by means of two laminar elements (8, 10) placed one above the other and which are held or fixed in the container (4), in which a laminar element (8) is applied as the element lower laminar (8) with perforations (18) through which the gas or vapor of the container (4), can flow between the laminar elements (8, 10) during use, and in such a way that an increase occurs of the pressure between said laminar elements, characterized in that said laminar elements (8, 10) are placed on each other and are fixed on said container (4) exclusively on the circumferential edge (6) of the extraction opening (2) of said container (4), so that essentially at least the two layers (8, 10) of sheet material remain separated from each other along the entire surface area of the extraction opening (2) of the container (4), so that when during use the pressure between said two laminar elements (8, 10) exceeds an upper limit by at least a part of the seal that connects the upper laminar element with said edge is broken and / or said upper laminar element is torn allowing steam to escape between said laminar elements. 15. Method according to claim 14, in the that a gas-tight laminar element is applied to the gases and liquids as the laminar element or as the second laminar element (10) placed on the lower laminar element (8). 16. Method according to claim 14 or 15, in which the layers of laminar elements (8, 10) are fixed to the container (4) and / or each other, particularly by closing waterproof, in which the lower laminar element (8) is connected with the container (4) so that said connection is more resistant that the connection between the laminar element or each laminar element (10) placed thereon and said lower laminar element (8) and / or the container (4), so that the second laminar element (10) it looses at least partially during use as consequence of the increase in pressure between the laminar elements (8, 10) without lower laminar element (8) loosening with Regarding the container. 17. Method for the production of a device for food packaging and preparation according to any of the claims 14 to 16, wherein a container (4) is applied which It is divided into several compartments, in which at least the lower laminar element (8) is also fixed to the wall of Separation of the different compartments. 18. Method for food preparation, in that food is put inside a container (4) that is at least closed with a perforated lower laminar element (8) and a second laminar element (10) placed thereon, in which said lower laminar element (8) and said second laminar element (10) are attached to said container exclusively at the edge circumferential (6) of the extraction opening (2) of said container (4), in which essentially at least two layers of laminar elements (8, 10) remain separated from each other at along the entire surface area of the extraction opening (2) of the container (4), after which the container (4) is placed in a closed state inside an oven, particularly a microwave oven or steam oven, after which foods are heated so that steam is created inside the container that then flows at least partially between the perforated laminar element and the second laminar element and generates higher pressure between said laminar elements, so that the second sheet element is loosened at least partially and / or it tears at a position close to said circumferential edge to relieve said pressure increase at the same time as the element lower laminar remains attached to container and pressure within it something above the pressure is maintained atmospheric 19. Method for food preparation, in that food is placed inside a container (4), according to the claim 18, and wherein a container (4) is applied which is divided into several compartments, in which at least the lower laminar element (8) is also fixed to the wall of separation of said various compartments.