Method and device for covering an opening of a container for food products

Abstract

Method for covering an opening (2) of a container (1) for food products, comprising the method steps of: providing a container (1), positioning a flexible film (7) over the opening, providing a sealing element (200) having a sealing space (209), providing a pressure element (210), moving the sealing element and the pressure element from opposite sides of the folded perimeter wall (3) of the container towards each other, applying heat by the sealing element and / or the pressure element to the flexible film and sealing the flexible film to a peripheral area of the folded perimeter wall (3), and moving the sealing element and the pressure element away from each other and removing the sealed container.

Description

[0001] Method and device for covering an opening of a container for food products

[0002] The invention relates to a method for covering an opening of a container for food products such as a tray, tub, bucket, cup, dish or jar. The invention further relates to a device for covering an opening of a container for food products.

[0003] Food products are usually packaged in a container with a coverable opening. The opening can be covered with a lid and / or by a layer of foil material. The lid and / or the layer of foil material provides a barrier between the food product(s) contained in the container and the environment to keep the food product(s) fresh and to protect the food product(s) from contamination.

[0004] Current packaging methods and devices often cover the opening of a container by externally applying a foil material to the container opening. The foil material is usually sealed to the container by applying a pressure to the outside of the container opening. In practice, the foil material is sealed onto a peripheral top edge of a packaging. Known methods and devices seal the film material to the opening by using a sealing arm which slides across the film material. The abovementioned prior art sealing method result in the risk of damaging the film material and / or the container upon covering the container. A further disadvantage is the relative complex equipment that is required to perform the prior art sealing method.

[0005] The present invention aims to improve the abovementioned drawback(s). Thereto a first aspect of the invention is a method for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, comprising the method steps of: a) providing a container having an opening, and in particular a container body, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall comprising: a top edge portion adjacent to the opening and / or in contact with at least a part of the container body optionally comprising a bottom and outer side (circumference wall) defining a container interior, and a side edge portion extending, in particular outwardly, from and / or adjacent to and / or in contact with the top edge portion, wherein at least a part of the side edge portion extends in a downward direction, and preferably wherein at least part of the side edge portion is at least partially, preferably substantially, parallel to and / or at least partially aligned with at least part of the container body, b) providing and positioning a flexible film over the opening entirely covering the opening and at least partially covering the contour of the opening, in particular such that the top edge portion and / or at least part of the downwardly extending part of the side edge portion of the folded perimeter wall is covered with the flexible film, c) providing a sealing element having a sealing space for accommodating the folded perimeter wall of the container, d) providing a pressure element fitting into the inside of the folded perimeter wall of the container, e) moving the sealing element and the pressure element from opposite sides of the folded perimeter wall towards each other, such that the pressure element presses the inside of the folded perimeter wall that is covered with the flexible film in contact with the sealing space, in particular such that the pressure element presses the inside of the top edge portion that is covered with the flexible film and / or the inside of at least part of the side edge portion that is covered with the flexible film, preferably at least part of the inside of the downwardly extending part of the side edge portion, f) applying heat by the sealing element and / or the pressure element to the flexible film and sealing the flexible film to the folded perimeter wall, in particular to at least to at least part of the top edge portion of the folded perimeter wall and / or to at least part of the side edge portion, preferably at least a part of the downwardly extending part of the side edge portion, and g) moving the sealing element and the pressure element away from each other and removing the sealed container. As an alternative solution the present invention aims to improve the abovementioned drawback(s) by a method for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, comprising the method steps of: a) providing a container having an opening, and in particular a container body comprising a bottom and outer side (circumference wall) defining a container interior, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall comprising: a top edge portion adjacent to the opening and / or in contact with at least a part of the container body, and a side edge portion extending, in particular outwardly, from and / or adjacent to and / or in contact with the top edge portion, wherein at least a part of the side edge portion extends downwardly, and preferably wherein at least part of the side edge portion is at least partially, preferably substantially, parallel to and / or at least partially aligned with at least part of the container body, b) providing and positioning a flexible film over the opening entirely covering the opening and at least partially covering and protruding beyond the contour of the opening, in particular such that the top edge portion and / or at least part of the downwardly extending part of the side edge portion of the folded perimeter wall is covered with the flexible film, c) providing a sealing element, e) moving the sealing element to the top edge of the container such that the sealing element is in contact with the flexible film and the top edge, f) applying heat by the sealing element to the flexible film and sealing the flexible film to top edge portion of the folded perimeter wall, h) folding a part of the flexible film overhanging or protruding beyond the contour of the opening towards, and preferably against, the outer side of the container, in particular below the perimeter wall, such that the contour of the opening is covered by the flexible film and the part overhanging the contour is pleated along the outer side of the container, h) providing a second heat-seal element for sealing the pleaded part of the flexible film, i) heat sealing the pleaded part of the flexible film to the outside of the container, preferably wherein said second seal is separate from the first seal, and g) moving the sealing element and second heat-seal element away from the container and removing the sealed container. Folding over the overhanging part to the outside wall of the container may be performed by a part of the sealing element and / or second heat-seal element.

[0006] The method provides an improved and / or alternative way for covering the opening of a container, in particular for sealing a flexible film to a folded perimeter wall of a container. By applying pressure from the pressure element to the inside of the folded perimeter wall direct contact between the pressure element and the flexible film is reduced or limited, in particular prevented. This is advantageous since it decreases the risk of damaging the flexible film. The combination of the pressure element and the sealing element further allows to seal a flexible film to both a top edge portion and a side edge portion of the folded perimeter wall. Consequently, the formed seal is less prone to detachment, while the risk of damaging the flexible film and / or the container is reduced. As the pressure element and the sealing space are in contact with opposite sides of the folded perimeter wall this method also limits the risk of damaging the container. In particular wherein the sealing element and the pressure element are moved towards each other from the inside and the outside of the folded perimeter wall. Preferably, the pressures exerted by the pressure element may at least be partially cancelled out by the sealing element. Preferably, the sealing space, in particular the sealing element, is configured to provide a resistance force against the pressure applied by the pressure element. Therewith, the risk of damaging the flexible film and / or the container is further reduced. By means of this method, it is possible to apply a heat-seal to the peripheral top edge and the outside wall of a container, in which case the film / foil is not broken or damaged by the contact point of the device. Heat-sealing onto the outside wall of the packaging takes place at at least one location on the peripheral wall, and preferably in several locations.

[0007] The opening of the container provides access to the interior of the container body. The container may have a cylindrical, rectangular, or irregularly shaped container body. The contour of the opening of the container is formed by an outwardly folded perimeter wall. The perimeter wall protrudes outwardly or in an outward direction from the container, in particular from the opening. The perimeter wall may be referred to as a circumference wall. The inside of the folded perimeter wall may define a volume of the folded perimeter wall, in particular at least partially enclosed by a part of the outside wall of the container (body) and the folded perimeter wall. The outside of the folded perimeter wall may be described as the part of the folded perimeter wall extending from the opening of the container. The outside of the folded perimeter wall is in particular the opposite to the inside of the folded perimeter wall.

[0008] In the method a flexible film is provided which may be made of or comprise a polymer material such as a plastic foil or a plastic coated foil. Materials used for the foil are for instance polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and / or a polyester (PET). The flexible film may also comprise a metal, such as for instance an (plastic coated) aluminium layer and / or a paper layer.

[0009] In the method the flexible film is positioned over the opening entirely covering the opening. The flexible film may extend at least over a part of the folded perimeter. The flexible film may entirely cover the outside of the folded perimeter wall. Optionally, the flexible film may at least partially or entirely cover the inside of the folded perimeter wall. The flexible film also may have a variable length along the perimeter of the folded perimeter wall. For instance, the flexible film may comprise an extended portion, optionally forming a grip tab. Optionally, the flexible film is positioned over the opening such that the flexible film overhangs the folded perimeter wall thereby forming an overhanging edge. In that case, the flexible film does not only cover the opening but it also hangs downwardly along the periphery of the container or the contour of the container. Such a decorative overhanging edge may also be referred to as a “skirt”.

[0010] In the method a sealing element having a sealing space for accommodating the folded perimeter wall of the container is provided. Preferably, the sealing element is heatable, in particular at least the sealing space of the sealing element is heatable. A heatable sealing element and / or heatable sealing space is beneficial as it contributes to sealing the flexible film to a peripheral area of the folded perimeter wall. In particular, for sealing the flexible film at least to the outside of the folded perimeter wall.

[0011] In the method a pressure element fitting into the inside of the folded perimeter wall of the container is provided. The pressure element may extend along the container, in particular along the container body, and into at least part of the inside of the folded perimeter wall. Optionally, the part of the pressure element fitting into the inside of the folded perimeter wall may be a form-fitting end portion. Preferably, the pressure element is heatable, in particular at least the form-fitting end portion of the pressure element is heatable. A heatable pressure element and / or heatable formfitting end portion is beneficial as it contributes to sealing the flexible film to a peripheral area of the folded perimeter wall. In particular, for sealing the flexible film at least to the outside and / or to the inside of the folded perimeter wall. The pressure element may fit into the inside of a (peripheral) top edge portion of the folded perimeter wall. The top edge portion may be defined as a transition area of the container body and at least a part of the folded perimeter wall, in particular a side edge portion of the folded perimeter wall. Therewith, the outside of the (peripheral) top edge portion can be brought into contact with the sealing space. The (peripheral) top edge portion may form part of a peripheral area. Sealing the flexible film to the (peripheral) top edge portion may contribute to an improved sealing of the flexible film to the folded perimeter wall. Optionally, the pressure element may only fit into the inside of the side edge portion of the folded perimeter wall.

[0012] The method further comprises the step of applying heat by the sealing element and / or the pressure element to the flexible film and sealing the flexible film to the folded perimeter wall, in particular at least to at least part of the top edge portion and / or to at least part of the side edge portion, preferably the downwardly extending part of the side edge portion. Preferably, at least the sealing space of the sealing element is heated. The step of applying heat and sealing the flexible film may be referred to as heat-sealing the flexible film to the folded perimeter wall. The step of applying heat and sealing the flexible film to the folded perimeter wall may be understood to mean the actual fusing together of a flexible film and the folded perimeter wall, bonding a flexible film and the folded perimeter wall by means of an applied coating, in which case the coating may be applied to the folded perimeter wall and / or the flexible film. It is conceivable for this fusing and / or bonding to be brought about by way of a coating by means of an elevated temperature. However, it is also conceivable for this fusing and / or bonding to be brought about by way of a coating by means of a chemical process. More particularly, such a chemical process may comprise the use of a bonding agent, such as an adhesive. This adhesive may be applied separately or may, for example, already be present on one of the two components to be bonded. It is also conceivable for the adhesive to be multi-component adhesive, in which case one of the two types of adhesive is applied to each of the parts. In certain cases, a chemical process, and in particular the use of an adhesive, may make it possible to effect the bonding without (optionally local) heating. In particular, according to the present invention, a flexible film may be used as a bonding agent, in combination with heating, together with a coating as bonding agent, unheated or in combination with heating, or with an adhesive layer as heat-seal medium, unheated or in combination with heating. Optionally, the step of applying heat and sealing the flexible film may be referred to as welding the flexible film to the folded perimeter wall.

[0013] Preferably, the method steps, in particular steps a) to g) are subsequent steps. It is furthermore imaginable that the method steps, preferably at least steps a) to g), are iterated for covering the opening of a plurality of containers. Optionally, steps e) to g) are iterated for sealing the flexible film to the folded perimeter wall at multiple locations.

[0014] Preferably, during or after step b), in particular at least during step e) and / or step f), the flexible film contacts the folded perimeter wall over a perimeter of a bandshaped area. A band-shaped area may be referred to as a strip-shaped area. The band-shaped area may be referred to as a band-shaped contact area of the folded perimeter wall and the flexible film. Optionally, during step f) the flexible film is sealed to a band-shaped (peripheral) area. This embodiment provides a contact area of the flexible film and the folded perimeter wall which contributes to improving the covering of the opening of the container.

[0015] Preferably, during step e) and / or step f) the pressure element deforms at least part the folded perimeter wall, in particular at least part of the top edge portion and / or at least part of the side edge portion, more in particular at least part of the downwardly extending part of the side edge portion, to bring it in contact with the sealing element. Therewith, preferably only the folded perimeter wall deforms. In particular, the pressure element deforms at least the part of the folded perimeter wall with which the pressure element is in contact. During step e) and / or step f) the pressure element may press the folded perimeter wall towards the sealing space. In particular, during step e) and / or step f) the pressure element presses the folded perimeter away from the container body. The pressure element may elastically or plastically deform at least part the folded perimeter wall to bring it in contact with the sealing element. This embodiment improves contact of the folded perimeter wall that is covered with the flexible film with the sealing space. Hence, this embodiment improves the sealing the flexible film to a peripheral area of the folded perimeter wall.

[0016] During step f) the flexible film may, in particular only, be sealed to the outside of the folded perimeter wall, preferably to a peripheral area at the outside of the folded perimeter wall. The pressure element is free from contact with the flexible film, in particular at least during steps e) and / or f) and / or g). Preferably, the inside of the folded perimeter wall is free from flexible film. Leaving the inside of the folded perimeter wall free from the flexible film may require the flexible film to only be deformed and / or folded over a top (peripheral) edge portion and side edge portion of the folded perimeter wall. This embodiment particularly provides that the flexible film does not need to be folded over a bottom (peripheral) edge portion of the perimeter wall. A bottom (peripheral) edge portion may be defined as an end portion of the folded perimeter wall opposing the top peripheral edge portion. In particular, the bottom edge portion extends from the side edge portion of the folded perimeter wall. Hence, less deformation and / or folding of the flexible film is needed, whereby the risk of damaging the flexible film decreases. A further benefit is that by leaving the inside of the folded perimeter wall free from flexible film a user is able to relatively easily remove the flexible film from a sealed container.

[0017] A peripheral area may extends over the entire length of the folded perimeter wall. Preferably, the flexible film is sealed to the folded perimeter wall over the entire length of the folded perimeter wall, in particular after step f). In particular, the length of the perimeter wall may be defined by the length of the contour of the opening of the container. This embodiment improves the sealing, in particular the sealing strength, of the flexible film to the folded perimeter wall.

[0018] Preferably, the folded perimeter wall comprises a plurality of interrupted peripheral areas. The flexible film may be sealed to a plurality of interrupted, in particular mutually distant, seal locations on the top edge portion of the folded perimeter wall. Additionally or alternatively, the flexible film may be sealed to a plurality of interrupted, in particular mutually distant, seal locations on side edge portion of the folded perimeter wall, in particular on the downwardly extending part of the side edge portion. After step f) the flexible film may be sealed to the folded perimeter wall at interrupted (peripheral) areas. In particular, the plurality of interrupted (peripheral) areas and / or locations on the top edge portion and / or side edge portion are distributed along the length of the folded perimeter wall, more in particular along the entire length of the folded perimeter wall. Preferably, the seal locations of the flexible film on the top edge portion and the seal locations of the flexible film on the side edge portion are mutually shifted in a circumferential direction of the folded perimeter wall. Optionally, each seal location of the flexible film on the top edge portion is staggered with respect to each seal location of the flexible film on the side edge portion. Since the flexible film is sealed at interrupted (peripheral) areas and / or seal locations on the top edge portion and / or seal locations on the side edge portion, less contact between the flexible film and the sealing element and / or pressure element is needed. This contributes to less risk on damaging the container and / or the flexible film. Additionally, the flexible film is sealed to a plurality of seal locations which contributes to an improved sealing. An additional benefit is that this embodiment provides a sufficient sealing properties of the flexible film while providing a relatively easy way to remove the flexible film from a sealed container. Preferably, during step e) the pressure element locally presses the inside of the folded perimeter wall, in particular at and / or close to the (peripheral) area and / or location to which the flexible film is to be sealed. By locally pressing the inside of the folded perimeter wall, a specific (peripheral) area(s) and / or location(s) is brought into contact with the sealing space. Therewith, a degree of deformation of the folded perimeter wall, if present, decreases which contributes to decreasing the risk of damaging the container and / or the flexible film.

[0019] The sealing space may be configured to accommodate the entire folded perimeter wall of the container. In particular, the sealing space is configured to accommodate the entire outside of the folded perimeter wall of the container. Optionally, the sealing space is configured for only accommodating the peripheral area. The sealing space may have a shape complementary to the contour of the opening of a container. This embodiment contributes to improving the contact of the folded perimeter wall that is covered with the flexible film with the sealing space.

[0020] Therewith, an improved sealing of the flexible film to the folded perimeter wall can be obtained.

[0021] During step f) the sealing element and / or the pressure element is preferably heated to a temperature between approximately 100 to 200°C, preferably between approximately 130 to 180°C. In particular, at least the sealing space is heated to a temperature between approximately 100 to 200°C, preferably between approximately 130 to 180°C. The temperature applied during step f) is in particular dependent on the material properties of the flexible film and / or of the folded perimeter wall. The elevated temperature preferably allows fusing together the flexible film and the peripheral area of the folded perimeter wall. Optionally, when a coating is applied, the elevated temperature allows bonding of the flexible film and the peripheral area of the folded perimeter wall. This embodiment contributes an improved sealing of the flexible film to the folded perimeter wall can be obtained.

[0022] The method preferably comprises a step h) of applying an adhesive or a glue to at least a part of the folded perimeter wall and adhering the flexible film to the folded perimeter wall, wherein step h) is performed prior to step f). Preferably, step h) is performed prior to step e), more preferably step h) is performed prior to step b). Preferably, the adhesive or glue is applied to the top edge portion and / or the side edge portion, preferably at least the downwardly extending part of the side edge portion, of the folded perimeter wall. Additionally or alternatively, the adhesive is applied to the flexible film. The addition of an adhesive provides an improvement in the sealing properties of the flexible film to the peripheral area of the folded perimeter wall. The adhesive is preferably a food-grade melt adhesive and / or a water-based adhesive and / or a pressure-sensitive adhesive. The adhesive or glue preferably comprises polyvinyl acetate and / or cyanoacrylate and / or natural adhesive components, such as gelatine, starch and / or cellulose. If step h) is performed, it is not necessary to apply heat during step f). Hence, if step h) is applied, step f) may be replaced by a step f1) of sealing the flexible film to a peripheral area of the folded perimeter wall. In that case, preferably a pressuresensitive adhesive is used during step h). The combination of step h) and step f1 ) provides an alternative to heat-sealing the flexible film to the peripheral area. If the folded perimeter wall comprises a plurality of interrupted peripheral areas, it is imaginable that a part of the interrupted peripheral areas are provided with an adhesive during step h). Preferably, all interrupted peripheral areas are provided with an adhesive during step h).

[0023] The sealing element may be static. In that case, the pressure element is moved towards the sealing element during step e). Hence, during step d) and / or step e), the pressure element is provided in the inside of the folded perimeter wall and moves or brings at least the folded perimeter wall towards the sealing element. Preferably, during step d) and / or step e), the pressure element moves or brings the container towards the sealing element. This embodiment requires less moveable components which contributes to the need of less complex equipment for the sealing method. Hence, this embodiment provides a more robust system.

[0024] The pressure element may comprise a first pressure portion and a second pressure portion, wherein the first pressure portion is positioned closer to at least part of, in particular an outer side of, a container body of the container than the second pressure portion, and wherein during step e), and optionally during step f), the first pressure portion presses at least part of the top edge portion of the folded perimeter wall in contact with the sealing space and the second pressure portion presses the side edge portion, in particular the downwardly extending part of the side edge portion, of the folded perimeter wall in contact with the sealing space. This embodiment is beneficial as it improves, in particular specific, contact of the folded perimeter wall with the sealing space to seal the flexible film to specific location(s) on the top edge portion and the side edge portion. Therewith an improved sealing of the flexible film to the folded perimeter wall can be obtained.

[0025] Preferably, during step b) the flexible film is provided over the entire contour of the container, wherein at least a part of the flexible film overhangs the folded perimeter wall of the container, in particular at a bottom end portion of the folded perimeter wall. The method may further comprise a step of connecting portions of a perimeter edge of the flexible film to each other, thereby forming a skirt. The step of connection portions of the perimeter edge of the flexible film to each other may be performed after step d), preferably prior to or during or after step e).

[0026] The flexible film provided during step b) is preferably at least partially composed of or comprises a shape memory film material, such as a shape memory alloy, SMA, and / or a shape memory polymer, SMP. Preferably, an original shape of the flexible film is the shape as sealed to the folded perimeter wall. When removing the flexible film from the container to which it is sealed to open the container, the flexible film at least partially deforms back from a deformed state to the original state. Hence, the flexible film may be reused for closing the opening of the container. The shape memory properties of the shape memory film material may allow the flexible film to conform more closely to the perimeter wall of the container and thereby providing a more tight seal.

[0027] Preferably, during step a) at least one compartment is provided in the opening of the container. During step b) the flexible film may entirely cover said at least one compartment. Optionally, the opening of the container provided during step a) may be divided into a plurality of separate compartments, and wherein during step b) the, in particular single one, flexible film preferably entirely covers all said separate compartments. A container comprising one or more (separate) compartments is beneficial for separately accommodating food products. Adjacent compartments may be mutually separated by walls. The invention allows to provide one flexible film covering one or the plurality of compartments. The sealing according to the present invention is capable of sealing the flexible film to the perimeter wall of the container (body), such that displacement of food products when accommodated in the compartments between adjacent compartments is circumvented. This not only reduces the material needed to close a container comprising compartments, but may also improve the strength of the individual compartment. In particular, providing said flexible film over the plurality of compartments allows to distribute forces more evenly across the flexible film and hence the plurality of compartments, thereby increasing the resistance of each container to deformation or damage. Covering all compartments with a single flexible film may provide a uniform seal across the entire opening. This may help maintain the integrity of each compartment and prevent cross-contamination between sections. A further benefit of sealing the multiple compartments with a single flexible film is that the sealing process can be simplified as less sealing steps and / or equipment is required.

[0028] A second aspect of the invention relates to a device for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall comprising: a top edge portion adjacent to the opening, and a side edge portion extending from the top edge portion, wherein at least a part of the side edge portion extends in a downward direction, the device comprises: a pressure element having a form-fitting end portion which fits into an inside of the outwardly folded perimeter wall, a sealing element having a sealing space for accommodating, in particular an outside of, the folded perimeter wall of the container, wherein the sealing space comprises: a first region for accommodating a top edge portion of the folded perimeter wall of a container, and a second region for accommodating at least part of the side edge of the folded perimeter wall of a container, in particular at least the downwardly extending part of the side edge portion of the folded perimeter wall of a container, a drive for mutually moving the pressure element and the sealing element between: an initial position, wherein the pressure element and the sealing element are located at a distance from each other, and a sealing position, wherein the pressure element and at least part of the sealing element are aligned and located close to each other, wherein at least in the sealing position at least a part of the pressure element is moveable between: a first position, wherein at least part of the pressure element, in particular at least the form-fitting end portion, is aligned with the first region of the sealing space for allowing to press or bring the top edge portion of a container in contact with the sealing space, and a second position, wherein at least part of the pressure element, in particular at least the form-fitting end portion, is aligned with the second region of the sealing space for allowing to press or bring the side edge portion, in particular at least the downwardly extending part of the side edge portion, of a container in contact with the sealing space, and wherein at least in the sealing position at least part of the sealing element and / or at least part of the pressure element is configured to be heated for sealing a flexible film to at least a part of the top edge portion and to at least a part of the side edge portion, in particular to the downwardly extending part of the side edge portion, of the folded perimeter wall of the container. Preferably, at least the form-fitting end portion of the pressure element is moveable between the first position and the second position. In the first position the pressure element, in particular the form-fitting end portion, may be configured to apply a pressure at least to a part of the top edge portion of a container. In the second position the pressure element, in particular the form-fitting end portion, may be configured to apply a pressure to at least to a part of a side edge portion, in particular a downwardly extending part of the side edge portion. Preferably, in the first position at least part of the pressure element, in particular at least the form-fitting end portion, is aligned with the first region of the sealing space for allowing to press or bring the top edge portion of a container which is covered with a flexible film in contact with the sealing space. Preferably, in the second position at least part of the pressure element, in particular at least the form-fitting end portion, is aligned with the second region of the sealing space for allowing to press or bring the side edge portion, in particular at least the downwardly extending part of the side edge portion, of a container which is covered with a flexible film in contact with the sealing space. Consequently, the flexible film provided on top of the top edge portion and / or on at least part of a side edge portion particularly comes into direct contact with the sealing space. The pressure element, in particular the form-fitting end portion, particularly comes into direct contact with the folded perimeter wall of the container.

[0029] In an alternative solution the invention relates to a device for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall comprising: a top edge portion adjacent to the opening, and a side edge portion extending from the top edge portion, wherein at least a part of the side edge portion extends downwardly, the device comprises: a sealing element for sealing, in particular heat sealing, of the folded perimeter wall of the container, a drive for moving the sealing element between: an initial position, wherein the sealing element is at a distance from the perimeter wall, and a sealing position, wherein at least in the sealing position at least a part of the sealing element is pressing the flexible film against the perimeter wall, a bending element, for bending a part of the flexible film overhanging beyond the contour of the opening of the peripheral top edge over the top edge as far as against the outside wall of the container, a second heat-seal element, wherein said second heat seal element is movable, preferably by said drive, in a different direction with respect to the sealing element, wherein said second heat-seal element is movable to heat-seal a part of the flexible film protruding beyond the contour of the opening to an outside of the container. The device is capable of producing a double heat-seal, the second heatseal being performed by means of a movable second heat-seal element, wherein the second heat-seal element, at least with one directional component, is movable substantially perpendicularly to the peripheral wall, and wherein the second heatseal element is configured to force the film / foil layer towards the peripheral wall during heat-sealing.

[0030] The device provides an improved and / or alternative way for covering the opening of a container, in particular for sealing a flexible film to a folded perimeter wall of a container. By providing a form-fitting end portion which fits into the inside of the outwardly folded perimeter wall direct contact between the pressure element, in particular the form-fitting end portion, and the flexible film is reduced or limited, in particular prevented. This is advantageous since it decreases the risk of damaging the flexible film. In the sealing position, the pressure element and the sealing space are in contact with opposite sides of the folded perimeter wall. Preferably, wherein the sealing element and the pressure element are moved towards each other from the inside and the outside of the folded perimeter wall, respectively. Therewith, the device according to the invention contributes to limiting the risk of damaging the container. The combination of the moveable pressure element and the sealing element further allows to seal a flexible film to both a top edge portion and a side edge portion, in particular the downwardly extending part of the side portion, of the folded perimeter wall. Consequently, the formed seal is less prone to detachment, while the risk of damaging the flexible film and / or the container is reduced.

[0031] Furthermore, the device according to the second aspect of the invention contributes to simplifying the equipment for sealing a flexible film to the folded perimeter wall of a container. The drive is configured for mutually moving the pressure element and the sealing element between the initial position and the sealing position. In the initial position, the pressure element, in particular the form-fitting end portion, and the sealing element are located at a distance from each other, preferably such that a container to be covered can be placed in the device and / or such that a covered or sealed container can be removed from the device. In the sealing position, the pressure element and the sealing element are aligned and located close to each other, preferably such that the sealing element and the pressure element are in contact with opposite sides of the folded perimeter wall of a container. In the sealing position the pressure element, in particular the form-fitting end portion, is configured to apply a force, in particular a pressure, to the inside of the folded perimeter wall for bringing the folded perimeter wall in contact with the sealing element, in particular in contact with the sealing space. If the folded perimeter wall is covered with a flexible film, the pressure element is configured to bring the flexible film (also) into contact with the sealing element, in particular the sealing space. By applying pressure from the inside of the folded perimeter wall, the flexible film, if the opening of the container is covered therewith, is exposed to less direct contact with the pressure element. This contributes to the decreasing the risk of damaging the flexible film. Since the pressure element and the sealing element are aligned in the sealing position, the device is configured to make contact with opposite sides of the folded perimeter wall of a container. This contributes to decreasing the risk of damaging the container, in particular the container body. Preferably, the sealing space, in particular the sealing element, is configured to provide a resistance force against the pressure applied by the pressure element. This further contributes to decreasing the risk of damaging the damaging the container and / or the flexible film.

[0032] The device is preferably suitable for use in a method according to the first aspect of the invention. Aforementioned embodiments relating to the first aspect of the invention may be applied and / or implemented in the device according to the second aspect of the invention. Similar or equal features between the method and the device may have the same or similar benefits as indicated above.

[0033] The device comprises a pressure element which comprises a form-fitting end portion. The form-fitting end portion is preferably configured to be placed into the inside of a peripheral top edge portion of a folded perimeter wall defined by a transition area of the container body of the folded perimeter wall. Preferably, the form-fitting end portion entirely fits into the inside of the outwardly folded perimeter wall. Preferably, at least a part of the pressure element is heatable, in particular at least a part of the form-fitting end portion is heatable, more preferably the entire form-fitting end portion is heatable. Hence, in the sealing configuration, at least part of the pressure element, in particular the form-fitting end portion, is configured to be heated for sealing a flexible film to a peripheral area of the folded perimeter wall of the container. A heatable pressure element and / or heatable form-fitting end portion is beneficial as it contributes to sealing the flexible film to the peripheral area of the folded perimeter wall. In particular, for sealing the flexible film at least to the outside and / or to the inside of the folded perimeter wall. This embodiment preferably allows the peripheral top edge portion to be brought into contact with the sealing space in the sealing position. Hence, the peripheral top edge portion may form part of the peripheral area which contributes to an improvement of the sealing of the flexible film to the folded perimeter wall.

[0034] The device comprises a sealing element including a sealing space configured for accommodating at least a part of the outside of the folded perimeter wall of the container. The sealing space comprises a first region configured to accommodate at least part of the outside of the top edge portion of the folded perimeter wall and a second region configured to accommodate at least part of the outside of the side edge portion of the folded perimeter wall, in particular the downwardly extending part of the side edge portion. The first region and the second region may be adjacent regions. Preferably, the first region and the second region are integral regions. The first region and the second region of the sealing space may mutually enclose an angle. Preferably, at least a part of the sealing element is heatable, in particular at least a part of the sealing space is heatable, more preferably the entire sealing space is heatable. Hence, in the sealing configuration, at least part of the sealing element, in particular at least part of the sealing space, is configured to be heated for sealing a flexible film to a peripheral area of the folded perimeter wall of the container. A heatable sealing element and / or heatable sealing space is beneficial as it contributes to sealing the flexible film to the peripheral area of the folded perimeter wall. In particular, for sealing the flexible film at least to the outside of the folded perimeter wall. This embodiment contributes to improving the sealing of the flexible film to the folded perimeter wall of a container.

[0035] Preferably, the drive is configured for mutually moving the pressure element and the sealing space between an initial position, wherein the pressure element and the sealing space are located at a distance from each other, and a sealing position, wherein the pressure element and at least part of the sealing space are aligned and located close to each other, wherein at least in the sealing position at least part of the sealing space and / or at least part of the pressure element is heated for sealing a flexible film to a peripheral area of the folded perimeter wall of the container. Optionally, in the sealing position, at least part of the form-fitting end portion is configured to be heated for sealing a flexible film to a peripheral area of the folded perimeter wall of the container. This embodiment contributes to simplifying the equipment needed for covering the opening of a container. According to this embodiment, the sealing space and / or the pressure element, in particular the formfitting end portion, are heated. Hence, this embodiment allows for decreasing the risk of damaging the flexible film and / or the container since less, preferably none, unnecessary parts of the flexible film and / or container are heated. Furthermore, this embodiment requires a smaller surface that needs to be heated and therewith less energy consumption is required for sealing a flexible film to the folded perimeter wall of a container. The drive may furthermore be configured to move the pressure element between the first position and the second position. Optionally, the device comprises an additional drive configured to move the pressure element between the first position and the second position.

[0036] Preferably, the form-fitting end portion is moveable relative to a remaining part of the pressure element, such that in the first position the form-fitting end portion and the remaining part are aligned and in the second position the form-fitting end portion and the remaining part mutually enclose an angle. Preferably, the formfitting end portion is moveable relative to a remaining part of the pressure element between: an aligned state, wherein the form-fitting end portion and the remaining part are aligned, and a diverged state, wherein the form-fitting end portion is outwardly displaced relative to the remaining part. In the aligned state the formfitting end portion is configured to be placed into the inside of the outwardly folded perimeter wall and / or to be brought into contact with the inside of the top edge portion of the perimeter wall. In the diverged state, the form-fitting end portion is configured to be brought in contact with the inside of the folded perimeter wall, in particular to at least part of the side edge portion, more in particular a downwardly extending part of the side edge portion. In the sealing position, the form-fitting end portion is in particular configured for applying a force, in particular a pressure, to the inside of the folded perimeter wall. Preferably, in the initial position, the formfitting end portion and the pressure element are in the aligned state for placing the form-fitting end portion in the inside of the folded perimeter wall. The form-fitting end portion is preferably in the aligned state and / or in the diverged state in the sealing position, such that the form-fitting end portion is configured to apply pressure to the inside of the folded perimeter wall. In the aligned state, the formfitting end portion is in line with the remaining part of the pressure element. In the diverged state, the remaining part and the form-fitting end portion form an angle. The angle is preferably between 170° and 90°, more preferably between 150° and 100°. Preferably, in the aligned state, the form-fitting end portion is in line with a longitudinal axis extending in a longitudinal direction of the remaining part. Optionally, in the aligned state, the form-fitting end portion is in line with a vertical axis extending in a vertical direction of the pressure element, in particular in a vertical direction of the remaining part. Preferably, in the aligned state, the formfitting end portion and the remaining part follow the shape of a container (body). In the diverged state, the form-fitting end portion and the remaining part are mutually displaced, in particular such that the form-fitting end portion diverges relative to the remaining part. In the diverged state, the form-fitting end portion is preferably at least partially outwardly displaced with respect to the remaining part. Optionally, in the diverged state, the form-fitting element is outwardly displaced relative to a vertical axis extending in a substantial vertical direction of the pressure element, in particular of the remaining part. Preferably, in the diverged state, the form-fitting end portion is outwardly displaced relative to the longitudinal axis extending in the longitudinal direction of the remaining part. Preferably, in the diverged state, the remaining part follows the shape of a container (body) and the form-fitting end portion is moved in a direction away from or outwardly relative to the container (body). This embodiment improves the contact of the folded perimeter wall of a container with the sealing space in the sealing position. Therewith an improved sealing of the flexible film to the folded perimeter wall can be obtained. Preferably, the form-fitting end portion is expandable, in particular relative to a remaining part of the pressure element, between a non-expanded state and an expanded state, wherein at least in the second position, and preferably in the first position, the form-fitting end portion is in the expanded state. In the sealing position at least a part of the form-fitting end portion may simultaneously be positioned in the first position and the second position. In the sealing position, at least part of the form-fitting end portion is preferably aligned with at least part of the inside of the top edge portion of the folded perimeter wall and simultaneously with at least part of the side edge portion, in particular at least part of the downwardly extending part of the side edge portion. In an expanded state, the form-fitting end portion may be configured for applying a pressure to the inside of the outwardly folded perimeter wall, in particular to the inside of the side edge portion and / or the top edge portion. The form-fitting end portion is preferably in the expanded state in the sealing position. Preferably, in the initial position, the form-fitting end portion is in a nonextended state such that the form-fitting end portion can easily be fitted into the inside of the folded perimeter wall. It is imaginable that the form-fitting end portion is inflatable. The form-fitting is preferably at least expandable in a diverging direction relative to the remaining part of the pressure element. The form-fitting end portion is preferably expandable in a perpendicular direction to a vertical axis extending in a substantial vertical direction of the remaining part of the pressure element. In particular, the form-fitting end portion is expandable in a transversal direction of the remaining part. This embodiment allows for an alternative way for improving the contact of the folded perimeter wall of a container with the sealing space in the sealing position. Hence, this embodiment contributes to improving the sealing of the flexible film to the folded perimeter wall.

[0037] Additionally or alternatively, the form-fitting end portion may be extendable relative a remaining part of the pressure element, wherein in the extended state the formfitting end portion is configured for applying a pressure to the inside of the outwardly folded perimeter wall. The form-fitting end portion is preferably extendable in a diverging direction relative to the remaining part of the pressure element. In particular, in the sealing position the form-fitting portion is in the extended state and preferably in the initial position the form-fitting portion is in an non-extended state. This embodiment may improve the contact of the folded perimeter wall of a container with the sealing space in the sealing position. Hence, this embodiment contributes to improving the sealing of the flexible film to the folded perimeter wall.

[0038] Preferably, the pressure element comprises at least two mutually displaceable components each comprising a form-fitting end portion, wherein at least in the sealing position at least one first component is configured to be, preferably solely, displaced to the first position and at least one second component is configured to be, preferably solely, displaced to the second position. Preferably, the at least two mutually displaceable components of the pressure element are displaceable to a mutually distinct position. Preferably, the pressure element comprises at least two mutually displaceable parts or components extending in a downward direction from the form-fitting end portion, wherein the mutually displaceable parts are displaceable in a direction towards the form-fitting end portion and in a direction away from the form-fitting end portion. It is imaginable that the mutually displaceable parts are displaceable relative to each other in a direction towards and in a direction away from the form-fitting end portion. This embodiment contributes to bringing the form-fitting end portion into contact with, in particular a specific location at, the inside of the outwardly folded perimeter wall of the container. In particular, the mutually displaceable parts assist the form-fitting end portion in applying a pressure to the inside of the outwardly folded perimeter wall of the container. Optionally, the mutually displaceable parts may contribute to bringing the top edge portion and / or the side edge portion of the folded perimeter wall which is covered with a flexible film into contact with the sealing element, in particular the sealing space, for sealing the flexible film to the peripheral area. Hence, this embodiment contributes to improving the sealing of the flexible film to the folded perimeter wall.

[0039] Preferably, a footprint defined by the pressure element has a geometrical shape. The footprint may be referred to as a plane. The geometrical shape may at least partially correspond to the shape of the container (body). Preferably, the form-fitting end portion follows the geometrical shape of the pressure element. This embodiment contributes to the need of less complex equipment and hence a more robust device for covering an opening of a container. It furthermore contributes in decreasing the risk of damaging the container by distributing the force(s) along the geometrical shape upon sealing a flexible film to the folded perimeter wall of a container in the sealing position. Preferably, the pressure element is configured to surround a container, in particular to accommodate a container. The geometrical shape may be a closed shape for entirely surrounding a container. This container surrounding pressure element may be configured for holding the container in place at least in the sealing position. This decreases the risk of damaging the flexible film and / or the container.

[0040] Preferably, the form-fitting end portion is ring-shaped. A ring-shaped form-fitting end portion particularly fits into the inside of a folded perimeter wall having a circular and / or an ellipsoidal shape. Preferably, the ring-shaped form-fitting end portion fits into the inside of the top edge portion and the side edge portion, in particular the downwardly extending part of the side edge portion, of the perimeter wall. Preferably, the ring-shaped form-fitting end portion fits into the entire inside of the outwardly folded perimeter wall. The ring-shaped form-fitting end portion may be configured to extend along the entire length of the folded perimeter wall. Preferably, in the sealing position, the ring-shaped form-fitting portion is configured to apply pressure over the entire length of the inside of the outwardly folded perimeter wall. Optionally, a peripheral area of the folded perimeter wall extends over the entire length of the folded perimeter wall. In that case, if a ring-shaped form-fitting end portion is used in the sealing position, a flexible film is sealed to the folded perimeter wall over the entire length of the folded perimeter wall of the container. This embodiment allows for increasing a peripheral area and improves the contact of the folded perimeter wall of a container with the sealing space in the sealing position. Hence, this embodiment contributes to improving the sealing of the flexible film to the folded perimeter wall can be obtained. Furthermore, a ringshaped form-fitting end portion contributes to a robust device for covering an opening of a container. It furthermore contributes in decreasing the risk of damaging the container by distributing the force(s), in particular the pressure, applied to the folded perimeter wall in the sealing position.

[0041] The device according to the second aspect of the invention preferably comprises a film providing structure for providing and positioning a flexible film over the opening of the container in the initial position. In particular, the film providing structure is configured for positioning a flexible film over the opening such that the flexible film entirely covers the opening of the container. Optionally, the film providing structure is configured for positioning a flexible film such that the flexible film extends over the full folded perimeter wall. The film providing structure may be configured for positioning a flexible film such that the flexible film overhangs the folded perimeter wall thereby forming an overhanging edge. This embodiment provides a less labour-intensive device for covering an opening of a container. The film providing structure may be connected to a drive for moving the film providing structure towards and away from the opening of a container. Preferably, the drive is configured to move the film providing structure towards and / or away from the opening of the container in the initial position. Preferably, the drive is configured to halt movement once the device is in the sealing position. Therewith, this embodiment contributes to decreasing the risk of damaging the flexible film upon covering the container.

[0042] The device according to the second aspect of the invention preferably comprises a holder for retaining a container, wherein the pressure element is connected to said holder. In particular, the pressure element extends in an upward direction from the holder, preferably such that the form-fitting end portion can be brought into the inside of the outwardly folded perimeter wall of a container received in the holder. The holder preferably surrounds a container. The holder may be configured for retaining the container in place in the sealing position, such that a container is kept in place during sealing a flexible film to the folded perimeter wall of said container, at least in the sealing position. Therewith, this embodiment contributes to improvement of sealing the flexible film to the folded perimeter wall. Furthermore, the holder contributes to a robust system for covering a container. Preferably, the drive is configured for moving said holder relative to the sealing element, in particular the sealing space, such that the pressure element and the sealing element are moved between the initial position and the sealing position.

[0043] Preferably, the sealing element is static. In that case, the drive is configured for moving the pressure element between the initial position and the sealing position. Hence, the drive is configured for moving the pressure element in a direction towards and in a direction away from the static sealing element, in particular at least in a direction towards and in a direction away from the sealing space. That means that once the form-fitting end portion is provided in the inside of the folded perimeter wall of a container the movement of the pressure element towards and / or away from the static sealing element, in particular towards and / or away from the sealing space, driven by the drive results in the movement of the container, in particular at least the folded perimeter wall, towards and / or away from the sealing element, in particular towards and / or away from the sealing space. Optionally, if the device comprises a holder, the drive is configured form moving the holder towards and away from the sealing element. In this embodiment less moveable components are required and hence this embodiment contributes to reduction of complex equipment for covering the opening of the container.

[0044] The device according to the second aspect of the invention preferably comprises a drive control for controlling the mutual movement of the pressure element and the sealing element between the initial position and the sealing position. Optionally, the drive control is configured for controlling the speed of the mutual movement of the sealing element and the pressure element. Optionally, if the device comprises a holder, the drive control may be configured for controlling the movement of the holder. This embodiment allows a more controlled movement of the relative movement of the pressure element and the sealing element and hence contributes to the robustness of the device.

[0045] The sealing element is preferably made from a thermal conductive material. Preferably at least part of the sealing space is at least partially made from a thermal conductive material. Optionally, at least part of the pressure element, in particular at least part of the form-fitting end portion, is at least partially made from a thermal conductive material. A thermal conductive material may be a metal, like copper, aluminium, silver and / or gold, and / or a ceramic. This embodiment allows for an efficient thermal energy transfer, which contributes to improvement of the sealing properties of the device.

[0046] The device according to the second aspect of the invention preferably comprises a heat source connected to the sealing element and / or the pressure element for heating the sealing element and / or the pressure element at least in the sealing position for sealing a flexible film to the folded perimeter wall of the container. The heat source is preferably an electrical heat source or an inductive heat source. The device according to the second aspect of the invention may further comprise an adhesive applicator for applying an adhesive or a glue to the folded perimeter wall of a container. Preferably, the adhesive applicator is configured for applying an adhesive or a glue to at least the peripheral area. In particular, the adhesive applicator is configured for applying an adhesive or a glue to the outside of the outwardly folded perimeter wall. Alternatively or additionally, the adhesive applicator is configured for applying an adhesive or a glue to at least an adhesion portion of the flexible film, wherein the adhesion portion is a portion of the flexible film to be sealed to the folded perimeter wall. This embodiment improves the sealing of the flexible film to the folded perimeter wall. Hence, an improved sealed container can be retrieved from the device according to this embodiment. Optionally, the adhesive applicator is connected to a drive for moving the adhesive applicator in a direction towards and / or away from the folded perimeter wall of a container to be covered. Preferably, the drive is configured to move the adhesive applicator towards and / or away from the opening of the container in the initial position. Preferably, the drive is configured to halt movement once the device is in the sealing position. This allows for an automated way of applying an adhesive to the container and / or flexible film.

[0047] The invention will be further elucidated based upon the following non-limitative clauses.

[0048] 1 . Method for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, comprising the method steps of: a) providing a container having an opening, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall, b) providing and positioning a flexible film over the opening entirely covering the opening, c) providing a sealing element, optionally having a sealing space for accommodating the folded perimeter wall of the container, d) optionally, providing a pressure element fitting into the inside of the folded perimeter wall of the container, e) moving the sealing element and the pressure element from opposite sides of the folded perimeter wall towards each other, such that the pressure element presses the inside of the folded perimeter wall that is covered with the flexible film in contact with the sealing space, or moving the sealing element towards the folded perimeter wall, f) applying heat by the sealing element and / or the pressure element to the flexible film and sealing the flexible film to a peripheral area, in particular a top peripheral area, of the folded perimeter wall, and g) moving the sealing element and the pressure element away from each other and removing the sealed container

[0049] - Optionally, folding a part of the flexible film overhanging beyond the contour of the opening towards, and preferably against, the outer side of the container, in particular below the perimeter wall, such that the contour of the opening is covered by the foil layer and the part of the foil layer overhanging the contour of the opening is pleated along the outer side of the container, and preferably heat-sealing the folded-over flexible film to the outer side of the container at a distance from the peripheral top edge.

[0050] 2. Method according to clause 1 , wherein at least during step e) and f) the flexible film contacts the folded perimeter wall over a perimeter of a band-shaped area.

[0051] 3. Method according to clause 1 or clause 2, wherein during step e) and / or step f) the pressure element deforms at least part of the folded perimeter wall to bring it in contact with the sealing element.

[0052] 4. Method according to any of the preceding clauses, wherein during step f) the flexible film is sealed to the peripheral area at the outside of the folded perimeter wall.

[0053] 5. Method according to any of the preceding clauses, wherein the peripheral area extends over the entire length of the folded perimeter wall.

[0054] 6. Method according to any of the clauses 1 -4, wherein the folded perimeter wall comprises a plurality of interrupted peripheral areas. 7. Method according to any of the preceding clauses, wherein the sealing space is configured to accommodate the folded wall of the container over the entire perimeter.

[0055] 8. Method according to any of the preceding clauses, wherein during step f) the sealing element and / or the pressure element is heated to a temperature between approximately 100 to 200°C, preferably between approximately 130 to 180°C.

[0056] 9. Method according to any of the preceding clauses, comprising a step h) of applying an adhesive to at least a part of the peripheral area of the folded perimeter wall and adhering the flexible film to the folded perimeter wall, wherein step h) is performed prior to step f).

[0057] 10. Method according to any of the preceding clauses, wherein the sealing element is static.

[0058] 11 . Device for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall, the device comprises:

[0059] - an optional pressure element having a form-fitting end portion which fits into the inside of the outwardly folded perimeter wall,

[0060] - a sealing element having a sealing space for accommodating the outside of the folded perimeter wall of the container,

[0061] - a drive for, optionally mutually, moving the pressure element and the sealing element between: o an initial position, wherein the pressure element and the sealing element are located at a distance from each other, and preferably wherein the sealing element is at a distance from the container, and o a sealing position, wherein the pressure element and at least part of the sealing element are aligned and located close to each other, and preferably wherein the sealing element is in contact with the container, optionally, wherein at least in the sealing position at least part of the sealing element and / or at least part of the pressure element is configured to be heated for sealing a flexible film to a peripheral area of the folded perimeter wall of the container

[0062] Optionally, the device may comprise;

[0063] - a bending element for bending a part of the flexible film overhanging beyond the contour of the peripheral top edge over the peripheral top edge as far as against the outside wall of the container;

[0064] - a second heat-seal element, wherein said second heat-seal element is movable in a different direction with respect to the sealing element, wherein said second heat-seal element is movable to heat-seal a part of the flexible film protruding beyond the contour of the opening to an outside of the container.

[0065] 12. Device according to clause 11 , wherein the form-fitting end portion is moveable relative to a remaining part of the pressure element between: o an aligned state, wherein the form-fitting end portion and the remaining part are aligned, and o a diverged state, wherein the form-fitting end portion is outwardly displaced relative to the remaining part.

[0066] 13. Device according to clause 11 or 12, wherein the form-fitting end portion is expandable relative a remaining part of the pressure element, wherein the formfitting end portion is configured for applying a pressure to the inside of the outwardly folded perimeter wall and / or wherein the second heat-seal element is at least movable in a direction towards the outside wall of the container, and wherein the second heat-seal element is configured to force the film / foil layer towards the outside wall during heat-sealing.

[0067] 14. Device according to any of the clauses 11-13, wherein the form-fitting end portion is extendable relative a remaining part of the pressure element, wherein in the extended state the form-fitting end portion is configured for applying a pressure to the inside of the outwardly folded perimeter wall and / or wherein the sealing element and second heat-seal element are configured to engage at different positions on the container, wherein in particular a seal of the sealing element and a seal of the second heat-seal element are at a mutual distance. 15. Device according to any of the clauses 11-14, wherein the pressure element comprises at least two mutually displaceable parts extending in a downward direction from the form-fitting end portion, wherein the mutually displaceable parts are displaceable in a direction towards the form-fitting end portion and in a direction away from the form-fitting end portion.

[0068] 16. Device according to any of the clauses 11-15, wherein a footprint defined by the pressure element has a geometrical shape.

[0069] 17. Device according to any of the clauses 11-16, wherein the form-fitting end portion is ring-shaped.

[0070] 18. Device according to any of the clauses 11-17, comprising a film providing structure for providing and positioning a flexible film over the opening of the container in the initial position.

[0071] 19. Device according to any of the clauses 11-18, comprising a holder for retaining a container, wherein the pressure element is connected to said holder.

[0072] 20. Device according to any of the clause 19, wherein the drive is configured for moving the holder relative to the sealing element.

[0073] 21 . Device according to any of the clauses 11-20, wherein the sealing element is static and / or wherein the sealing element and second heat-seal element form a dynamic and movable heat sealing element.

[0074] 22. Device according to any of the clauses 11-21 , comprising a drive control for controlling the mutual movement of the pressure element and the sealing element between the initial position and the sealing position.

[0075] 23. Device according to any of the clauses 11-22, wherein the sealing element is made from a thermal conductive material.

[0076] 24. Device according to any of the clauses 11-23, comprising a heat source connected to the sealing element and / or the pressure element for heating the sealing element and / or the pressure element at least in the sealing position for sealing a flexible film to the folded perimeter wall of the container.

[0077] 25. Device according to any of the clauses 11-24, comprising an adhesive applicator for applying an adhesive to the folded perimeter wall of a container.

[0078] The invention will be further elucidated by several examples and with reference to the appended figures, wherein:

[0079] - Figure 1 schematically shows a method and a first embodiment of a device for covering an opening of a container for food products according to the first aspect of the invention,

[0080] - Figure 2 schematically shows an enlarged view of the circled area in figure 1 ,

[0081] - Figures 3a-3c schematically show a cross-sectional view of a second embodiment of a device for covering an opening of a container for food products according to the second aspect of the invention,

[0082] - Figures 4a and 4b schematically show a cross-sectional view of a third embodiment of a device for covering an opening of a container for food products according to the second aspect of the invention, and

[0083] - Figures 5a and 5b schematically show a cross-sectional side view of a device in the sealing position according the present invention.

[0084] Within these figures, similar reference numbers correspond to similar or equivalent elements or features.

[0085] Figure 1 schematically shows a method for covering an opening 2 of a container 1 for food products according to the invention. The method according to the invention comprises a step a) of providing a container 1 having an opening 2, wherein a contour of the opening 2 is formed by an outwardly folded perimeter wall 3. The embodiment shows a cross-sectional side view of a container 1 . The shown container 1 comprises a container body for retaining food products and at least one opening 2 providing access to the interior of the container body. In the shown embodiment, a compartment 19 is provided in the opening 2 of the shown container 1 . Alternatively, the opening 2 of the container may be divided into a plurality of separate compartments 19. The shown container body comprises a bottom wall 5 and at least one side wall 4. A first end of the shown side wall 4 is connected to the bottom wall 5 and a second end of the side wall 4 forms a (peripheral) top edge portion 6. Said peripheral top edge 6 may be defined as a transition area of the container body and the outwardly folded perimeter wall 3. The perimeter wall 3 further comprises a side edge portion 14 extending from the top edge portion 6. At least a part of the side edge portion 14 extends downwardly. The perimeter wall 3 may further comprise a bottom edge portion 13 extending from the side edge portion 14 and forming the end of the folded perimeter wall 3. The bottom edge portion 13 and the top edge portion 6 are arranged at opposite sides from the side edge portion 14. The contour of the opening 2 of the container 1 is formed by an outwardly folded perimeter wall 3. The perimeter wall 3 of the shown embodiment protrudes in an outward direction from the container 1 . The outwardly folded perimeter wall 3 has an outside 3a and an inside 3b.

[0086] In step b) of the method a flexible film 7 is provided and positioned over the opening 2 of the container 1 entirely covering the opening 2. In the shown embodiment, the flexible film 7 has a length which exceeds the length of the folded perimeter wall 3. In the shown embodiment, the opening 2, the top edge portion 6, the downwardly extending part of the side edge portion 14 of the folded perimeter wall 3 are covered with the flexible film 7. In the shown figure, during step b) the flexible film 7 entirely covers the shown compartment 19.

[0087] In step c) a sealing element 8 is provided. The sealing element 8 has a sealing space 9 for accommodating the folded perimeter wall 3 of the container 1 . In particular, the sealing space 9 is configured for at least accommodating the outside 3b of the folded perimeter wall 3 of the container 1 . The sealing space 9 is preferably also configured for accommodating at least part of the flexible film. The shown sealing space 9 is configured for accommodating the entire folded perimeter wall 3 of the shown container 1 . It is imaginable that the sealing space 9 is configured for accommodating at least a part of a folded perimeter wall 3 of a container 1 . In step d) a pressure element 10 fitting into the inside 3b of the folded perimeter wall 3 of the container 1 is provided. The pressure element 10 may entirely fit into the inside 3b of the folded perimeter wall 3. Alternatively, a part of the pressure element 10 may fit into the inside 3b of the folded perimeter wall 3. Optionally, the pressure element 10 fits into the inside 6b of the (peripheral) top edge portion 6 and / or the side edge portion 14. At least a form-fitting end portion 11 of the pressure element 10 fits into the inside of the folded perimeter wall 3.

[0088] In step e) the sealing element 8 and the pressure element 10 are moved from opposite sides of the folded perimeter wall 3 towards each other, in particular wherein the sealing element 8 and the pressure element 10 are moved towards each other from the inside 3b and the outside 3a of the folded perimeter wall 3, respectively, such that the pressure element 10 presses the inside 3a of the folded perimeter wall 3 that is covered with the flexible film 7 in contact with the sealing space 9. Hence, the pressure element 10 presses at least part of the inside 3a of top edge portion 6 and the side edge portion 14 in contact with the sealing space 9. Thereby, at least part of the folded perimeter wall 3, in particular the top edge portion 6 and / or the side edge portion 14, may at least partially (elastically) deform. In particular, the form-fitting end portion 11 of the pressure element 10 presses the inside 3a of the folded perimeter wall 3 that is covered with the flexible film 7 with the sealing space 9. The sealing element 8 and / or the pressure element 10 may be connected to a drive (not shown) for mutually moving the pressure element 10 and the sealing element 8.

[0089] In step f) heat is applied by the sealing element 8 and / or the pressure element 10 to the flexible film 7 and the flexible film 7 is sealed to a peripheral area P of the folded perimeter wall 3. In particular, at least the part of the sealing element 8 and / or the part of the pressure element 10 that is in contact with the flexible film 7 and / or that is in contact with the folded perimeter wall 3 is heated. In particular, at least part of the sealing space 9 and / or at least part of the form-fitting end portion 11 is heated. Preferably, the flexible film 7 is sealed to the folded peripheral wall 3 at least at the peripheral area P formed by the folded peripheral wall 3 covered by the flexible film 7 which contacts the sealing element 8 and the pressure element 10. The peripheral area P is at least formed by the top edge portion 6 and / or at least part of the side edge portion 14, in particular the downwardly extending part of the side edge portion 14.

[0090] In step g) the sealing element 8 and the pressure element 10 are moved away from each other and a sealed container 12 can be removed. In the shown embodiment, the peripheral area P extends from the (top) peripheral edge portion 6 of the folded perimeter wall 3 via the side edge portion 14 to at least a bottom peripheral edge portion 13 of the perimeter wall 3. In another embodiment, the peripheral area P may extend beyond the bottom peripheral edge portion 13. Alternatively, the peripheral area P extends over a part of the area between the top peripheral edge portion 6 and the bottom peripheral edge portion 13. Optionally, a part of the flexible film 17 extends beyond the perimeter wall 3.

[0091] The figure further shows an optional step h), wherein a part of the flexible film 17 which protrudes beyond the contour of the opening is folded towards the outer side or side wall 4 of the container 1 . In shown step h) the overhanging part of the flexible film 17 is folded towards the outer side 4 of the container 1 below the perimeter wall 3. The overhanging part of the flexible film 17 may be pleated along the outer side 4 of the container 1 . In step h) a second heat-seal element 18 is provided for sealing the overhanging part of the flexible film 17, in particular a pleaded part of the flexible film 17, to the outer side 4 of the container 1 . Step h) may be performed after step g) or after steps e), f). Optionally, step h) may replace the use of the pressure element 10 as shown in panels c)-g). Instead, first the flexible film 7 is sealed to the top edge 6 of the container 1 . A sealing element 8 may be used to seal the flexible film to the top edge 6 of the container 1 . Subsequently or simultaneously a second heat-seal element 18 may seal the overhanging part of the flexible film 17 to the outer side 4 of the container 1 .

[0092] Figure 1 also shows a first embodiment of a device 100 for covering the opening 2 of a container 1 for food products according to the second aspect of the invention. The device 100 comprises a pressure element 10 having a form-fitting end portion 11 which fits into the inside 3b of the outwardly folded perimeter wall 3. The device 100 further comprises a sealing element 8 having a sealing space 9 for accommodating the outside 3a of the folded perimeter wall 3 of the container 1 . The sealing space 9 comprises at least a first region Ri for accommodating the top edge portion 6 of the folded perimeter wall 3. The sealing space 9 further comprises a second region R2for accommodating at least part of the side edge portion 14 of the perimeter wall 3, in particular at least the downwardly extending part of the side edge portion. The first region Ri and the second region R2of the shown embodiment are integrally formed. The device 100 further comprises a drive (not shown) for mutually moving the pressure element 10 and the sealing element 8 between: an initial position, wherein the pressure element 10 and the sealing element 8 are located at a distance from each other, as shown in steps c), d) and g), and a sealing position, as shown in steps e), f), wherein the pressure element 10 and at least part of the sealing element 8 are aligned and located close to each other. The pressure element is moveable between: a first position (not shown), wherein at least part of the pressure element 10, in particular at least the formfitting end portion 11 , and the first region Ri of the sealing space 9 are aligned, in particular such that the flexible film 3 can be sealed to the top edge portion 6, and a second position, as shown in step e), f), wherein at least part of the pressure element 10, in particular at least the form-fitting end portion 11 , and the second region R2of the sealing space 9 are aligned, in particular such that the flexible film 3 can be sealed to the side edge portion 14. At least in the sealing position, steps e), f), at least part of the sealing element 8 and / or at least part of the pressure element 10 is configured to be heated for sealing a flexible film 7 to the folded perimeter wall 3 of the container 1 .

[0093] Figure 2 shows an enlarged view of the circled area in figure 1 , wherein the pressure element 10 and the sealing element 8 moved towards opposite sides of the folded perimeter wall 3 of the container 1 . The flexible film 7 is clamped between the pressure element 10 and the sealing element 8. A first contact area C1 may be defined by the area of contact between the sealing element 8, in particular the sealing space 9, and the flexible film 7 and / or the outside 3a of the folded perimeter wall 3. A second contact area C2 may be defined by the area of contact between the pressure element 10, in particular the form-fitting end portion 11 , and the flexible film 7 and / or the inside 3b of the folded perimeter wall 3. The peripheral area may be defined by an overlapping area of the first contact area C1 and the second contact area C2.

[0094] Figures 3a-3c schematically show a cross-sectional view of a second embodiment of a device 200 for covering an opening of a container 1 according to the second aspect of the invention. A flexible film 7 is provided and positioned over the opening of the container 1. The device 200 comprises a pressure element 210 having a form-fitting end portion 211 which fits into the inside 3b of an outwardly folded perimeter wall 3 of a container 1 and a sealing element 208 having a sealing space 209 for accommodating the outside 3a of the folded perimeter wall 3 of the container 1 . In the shown embodiment, the form-fitting end portion 211 and the sealing space 209 have at least a partial complementary shape. The shown pressure element 210 comprises a form-fitting end portion 211 and a remaining part 213. In the shown embodiment, the form-fitting end portion 211 and the remaining part 213 are moveable relative to each other. The form-fitting end portion 211 is connected to the remaining part 213 at a pivot point 212. A rotational axis R extends through the pivot point 212, wherein the form-fitting end portion 211 is preferably rotatable around said rotational axis R. Furthermore, a longitudinal axis L extends along the longitudinal direction of the remaining part 213.

[0095] Figure 3a shows the device 200 in an initial position, wherein the pressure element 210 and the sealing element 208, in particular the sealing space 209, are located at a distance from each other. In the shown initial position, the form-fitting end portion 211 and the remaining part 213 of the pressure element 210 are in an aligned state. In the aligned state at least part of the form-fitting end portion 211 is in line with the remaining part 213. In particular, the form-fitting end portion 211 is located on the longitudinal axis L of the remaining part 213. Hence, the form-fitting end portion 211 and the remaining part 213 preferably do not make an angle with each other. Optionally, the longitudinal axis is a vertical axis extending in a substantial vertical direction of the pressure element 210, in particular of the remaining part 213. In the aligned state, the form-fitting end portion 211 may be located on said vertical axis.

[0096] Figure 3b shows the device 200 in a sealing position, wherein the pressure element 210 is arranged in the first position. The pressure element 210, in particular the form-fitting end portion 211 , and the first region Ri of the sealing space 209 are aligned. Consequently, the flexible film 7 can be sealed to the top edge portion 6 of the folded perimeter wall 3 of the container 1 . In the shown first position, the form-fitting end portion 211 is aligned with the remaining part 213. In particular, the form-fitting end portion 211 is located on the longitudinal axis L of the remaining part 213. In an alternative embodiment, the form-fitting end portion 211 and the remaining part 213 may mutually enclose an angle.

[0097] Figure 3c shows the device 200 in a sealing position, wherein the pressure element 210 is arranged in the second position. The pressure element 210, in particular the form-fitting end portion 211 , and the second region R2of the sealing space 209 are aligned. Consequently, the flexible film 7 can be sealed to a side edge portion 14 of the folded perimeter wall, in particular the downwardly extending part of the side edge portion 14. The pressure element 210 and at least part of the sealing element 208, in particular at least part of the sealing space 209, are aligned and located close to each other. In the shown sealing position at least part of the sealing element 208, in particular at least part of the sealing space 209, and / or at least part of the pressure element 210, in particular at least part of the form-fitting end portion 211 , is configured to be heated for sealing the flexible film 7 to a peripheral area P of the folded perimeter wall 3 of the container 1 . In the shown sealing position, the form-fitting end portion 211 and the remaining part 213 of the pressure element 210 are in a diverged state. In the diverged state at least part of the form-fitting end portion 211 outwardly displaced relative to the remaining part 213. In particular, the form-fitting end portion 211 is rotated around the rotational axis R. In the shown diverged state, the form-fitting element 211 is outwardly displaced relative to the longitudinal axis L of the remaining part 213 of the pressure element. Optionally, the longitudinal axis is a vertical axis extending in a substantial vertical direction of the pressure element 210, in particular of the remaining part 213. In the diverged state, the form-fitting end portion 211 is at least outwardly displaced relative to the vertical axis. In the shown embodiment, the remaining part 213 at least partially follows the shape of a container 1 and the formfitting end portion 211 is moved in a direction away from or outwardly relative to the container 1 .

[0098] Figures 4a and 4b schematically show a cross-sectional view of a third embodiment of a device 300 for covering an opening of a container 1 according to the second aspect of the invention. A flexible film 7 is provided and positioned over the opening of the container 1. The device 300 comprises a pressure element 310 having a form-fitting end portion 311 which fits into the inside 3b of an outwardly folded perimeter wall 3 of a container 1 and a sealing element 308 having a sealing space 309 for accommodating the outside 3a of the folded perimeter wall 3 of the container 1 . The sealing space 309 comprises a first region Ri and a second region R2. In the shown embodiment, the form-fitting end portion 311 and the sealing space 309 have at least a partial complementary shape. The shown pressure element 310 comprises a form-fitting end portion 311 and a remaining part 313. In the shown embodiment, the form-fitting end portion 311 is expandable relative a remaining part 313 of the pressure element 310. A vertical axis V extends in a vertical direction from the remaining part 313 of the pressure element 310. The vertical axis V divides the form-fitting end portion 311 into two sub-portions 311 a, 311 b. Figure 4a shows the device 300 in an initial position, wherein the pressure element

[0099] 310 and the sealing element 308, in particular the sealing space 309, are located at a distance from each other. In the shown initial position, the form-fitting end portion

[0100] 311 is in a non-extended state allowing the form-fitting end portion 311 to be relatively easy be fitted into the inside 3b of the folded perimeter wall 3 of the container 1 . The outer edge 314a of a first sub-portion 311 a of the form-fitting end portion 311 is located at a first distance D1 from the vertical axis V. The outer edge 314b of a second sub-portion 311 b of the form-fitting end portion 311 is located at a second distance D2 from the vertical axis V. Optionally, the first distance D1 and the second distance D2 are preferably equal in size.

[0101] Figure 4b shows the device 300 in an sealing position, wherein the pressure element 310 and at least part of the sealing element 308, in particular at least part of the sealing space 309, are aligned and located close to each other. In the shown sealing position at least part of the sealing element 308, in particular at least part of the sealing space 309, and / or at least part of the pressure element 310, in particular at least part of the form-fitting end portion 311 , is configured to be heated for sealing the flexible film 7 to a peripheral area P of the folded perimeter wall 3 of the container 1 . In the shown sealing position, the form-fitting end portion 311 is in an extended state allowing the form-fitting end portion 311 apply a pressure to the inside 3b of the folded perimeter wall 3 of the container 1 . In the shown expanded state, the pressure element, in particular the form-fitting end portion 311 , is simultaneously in the first position and the second position. In particular, the inside 3a a part of the top edge portion 6 and a part of the side edge portion 14, in particular the downwardly extending part of the side edge portion 14, are in contact with the form-fitting end portion 311. Therewith, the form-fitting end portion 311 is configured to press both the top edge portion 6 and the side edge portion 14 in contact with the sealing space 209, respectively with the first region Ri and the second region R2. The form-fitting end portion 311 is expanded in an outwardly direction from or diverging direction of the remaining part 313 or container 1. In particular, the form-fitting end portion 311 is expandable in a perpendicular direction to the vertical axis V of the remaining part 313 of the pressure element 310. In particular, the outer edge 314a of the first sub-portion 311a of the formfitting end portion 311 is located at a third distance D3 from the vertical axis V. The outer edge 314b of the second sub-portion 311 b of the form-fitting end portion 311 is located at a fourth distance D4 from the vertical axis V. The third distance D3 and / or the fourth distance D4 is larger than the first distance D1 and / or the second distance D2. Optionally, the third distance D3 is larger than the fourth distance D4 allowing the form-fitting end portion 311 to apply a pressure to the inside 3b of the folded perimeter wall 3.

[0102] Figures 5a and 5b schematically show a cross-sectional side view of a device 500 in the sealing position according the present invention. The device 500 comprises a pressure element 500 and a sealing element 508 comprising a sealing space 509. The sealing space 509 comprises a first region Ri and a second region R2. The shown pressure element 510 comprises two mutually displaceable components 510a, 510b. Both components 510a, 510b comprise a form-fitting end portion 511 a, 511 b. In figure 5a, the pressure element 510 is positioned in the first position, wherein the first component 510a is aligned with the first region Ri of the sealing space 509. Upon applying heat by the pressure element 510, in particular the first component 510a, and / or the sealing element 508, in particular the sealing space 509, more in particular the first region Ri, the flexible film 7 can be sealed to the top edge portion 6 of the perimeter wall 3 of the container 1 .

[0103] In figure 5b, the pressure element 510 is positioned in the second position, wherein the second component 510b is aligned with the second region R2of the sealing space 509. Upon applying heat by the pressure element 510, in particular the second component 510b, and / or the sealing element 508, in particular the sealing space 509, more in particular the second region R2, the flexible film 7 can be sealed to the side edge portion 14, in particular a downwardly extending part of the side edge portion 14, of the perimeter wall 3 of the container 1 . Between the first position (figure 5a) and the second position (figure 5b), the two components 510a, 510b of the pressure element 510 are mutually displaceable. In the shown figures, the two components 510a, 510b of the pressure element 510 are mutually displaceable in a vertical direction.

[0104] It will be clear that the invention is not limited to the exemplary embodiments which are illustrated and described here, but that countless variants are possible within the framework of the attached claims, which will be obvious to the person skilled in the art. In this case, it is conceivable for different inventive concepts and / or technical measures of the above-described variant embodiments to be completely or partly combined without departing from the inventive idea described in the attached claims.

[0105] The verb 'comprise' and its conjugations as used in this patent document are understood to mean not only 'comprise', but to also include the expressions 'contain', 'substantially contain', 'formed by' and conjugations thereof.

Claims

Claims1 . Method for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, comprising the method steps of: a) providing a container having an opening, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall comprising:• a top edge portion adjacent to the opening, and• a side edge portion extending from the top edge portion, wherein at least a part of the side edge portion extends in a downward direction, b) providing and positioning a flexible film over the opening entirely covering the opening and at least partially covering the contour of the opening, such that the top edge portion and at least part of the downwardly extending part of the side edge portion of the folded perimeter wall is covered with the flexible film, c) providing a sealing element having a sealing space for accommodating the folded perimeter wall of the container, d) providing a pressure element fitting into an inside of the folded perimeter wall of the container, e) moving the sealing element and the pressure element from opposite sides of the folded perimeter wall towards each other, such that the pressure element presses the inside of the folded perimeter wall that is covered with the flexible film in contact with the sealing space, f) applying heat by the sealing element and / or the pressure element to the flexible film and sealing the flexible film to at least a part of the top edge portion of the folded perimeter wall and to at least a part of the downwardly extending part of the side edge portion, and g) moving the sealing element and the pressure element away from each other and removing the sealed container.

2. Method according to claim 1 , wherein at least during step e) and f) the flexible film contacts the folded perimeter wall over a perimeter of a band-shaped area.

3. Method according to claim 1 or claim 2, wherein during step e) and / or step f) the pressure element deforms at least part of the folded perimeter wall, in particularat least part of the top edge portion and / or at least part of the side edge portion, more in particular at least part of the downwardly extending part of the side edge portion, to bring it in contact with the sealing element.

4. Method according to any of the preceding claims, wherein during step f) the flexible film is sealed to the outside of the folded perimeter wall.

5. Method according to any of the preceding claims, wherein the flexible film is sealed to the folded perimeter wall over the entire length of the folded perimeter wall.

6. Method according to any of the preceding claims, wherein the flexible film is sealed to a plurality of interrupted, in particular mutually distant, seal locations on the top edge portion of the folded perimeter wall, and / or wherein the flexible film is sealed to a plurality of interrupted, in particular mutually distant, seal locations on side edge portion of the folded perimeter wall.

7. Method according to claim 6, wherein the seal locations of the flexible film on the top edge portion and the seal locations of the flexible film on the side edge portion are mutually shifted in a circumferential direction of the folded perimeter wall.

8. Method according to any of the preceding claims, wherein the sealing space is configured to accommodate the folded perimeter wall of the container over the entire perimeter.

9. Method according to any of the preceding claims, wherein during step f) the sealing element and / or the pressure element is heated to a temperature between approximately 100 to 200°C, preferably between approximately 130 to 180°C.

10. Method according to any of the preceding claims, comprising a step h) of applying an adhesive to at least a part of the folded perimeter wall and adhering the flexible film to the folded perimeter wall, wherein step h) is performed prior to step f)-11 . Method according to any of the preceding claims, wherein the sealing element is static.

12. Method according to any of the preceding claims, wherein the pressure element comprises a first pressure portion and a second pressure portion, wherein the first pressure portion is positioned closer to at least part of, in particular an outside of, a container body of the container than the second pressure portion, and wherein during step e), and optionally during step f), the first pressure portion presses at least part of the top edge portion of the folded perimeter wall in contact with the sealing space and the second pressure portion presses the side edge portion, in particular the downwardly extending part of the side edge portion, of the folded perimeter wall in contact with the sealing space.

13. Method according to any of the preceding claims, wherein the flexible film provided during step b) is at least partially composed of a shape memory material, such as a shape memory alloy, SMA, and / or a shape memory polymer, SMP.

14. Method according to any of the preceding claims, wherein during step a) at least one compartment is provided in the opening of the container, and wherein during step b) the flexible film entirely covers said at least one compartment.

15. Device for covering an opening of a container for food products, such as a tray, tub, bucket, cup, dish or jar, wherein a contour of the opening of the container is formed by an outwardly folded perimeter wall comprising: a top edge portion adjacent to the opening, and a side edge portion extending from the top edge portion, wherein at least a part of the side edge portion extends in a downward direction, the device comprises:- a pressure element having a form-fitting end portion which fits into an inside of the outwardly folded perimeter wall,- a sealing element having a sealing space for accommodating the folded perimeter wall of the container, wherein the sealing space comprises: o a first region for accommodating a top edge portion of the folded perimeter wall of a container, and o a second region for accommodating at least the downwardly extending part of the side edge portion of the folded perimeter wall of a container, a drive for mutually moving the pressure element and the sealing element between:o an initial position, wherein the pressure element and the sealing element are located at a distance from each other, and o a sealing position, wherein at least a part of the pressure element and at least part of the sealing element are aligned and located close to each other, wherein at least in the sealing position at least a part of the pressure element is moveable between:- a first position, wherein at least part of the pressure element, in particular at least the form-fitting end portion, is aligned with the first region of the sealing space for allowing to press the top edge portion of a container in contact with the sealing space,- a second position, wherein at least part of the pressure element, in particular at least the form-fitting end portion, is aligned with the second region of the sealing space for allowing to press at least the downwardly extending part of the side edge portion of a container in contact with the sealing space, and wherein at least in the sealing position at least part of the sealing element and / or at least part of the pressure element is configured to be heated for sealing a flexible film to at least a part of the top edge portion and to at least a part of the downwardly extending part of the side edge portion of the folded perimeter wall of the container.

16. Device according to claim 15, wherein the form-fitting end portion is moveable relative to a remaining part of the pressure element, such that in the first position the form-fitting end portion and the remaining part are aligned and in the second position the form-fitting end portion and the remaining part mutually enclose an angle.

17. Device according to claim 15 or 16, wherein the form-fitting end portion is expandable, in particular relative to a remaining part of the pressure element, between a non-expanded state and an expanded state, wherein at least in the second position, and preferably in the first position, the form-fitting end portion is in the expanded state.

18. Device according to any of the claims 15-17, wherein the pressure element comprises at least two mutually displaceable components each comprising a formfitting end portion, wherein at least in the sealing position at least one first component is configured to be displaced to the first position and at least one second component is configured to be displaced to the second position.

19. Device according to any of the claims 15-18, wherein a footprint defined by the pressure element has a geometrical shape.

20. Device according to any of the claims 15-19, wherein the form-fitting end portion is ring-shaped.21 . Device according to any of the claims 15-20, comprising a film providing structure for providing and positioning a flexible film over the opening of the container in the initial position.

22. Device according to any of the claims 15-21 , comprising a holder for retaining a container, wherein the pressure element is connected to said holder.

23. Device according to any of the claim 22, wherein the drive is configured for moving the holder relative to the sealing element.

24. Device according to any of the claims 15-23, wherein the sealing element is static.

25. Device according to any of the claims 15-24, comprising a drive control for controlling the mutual movement of the pressure element and the sealing element between the initial position and the sealing position.

26. Device according to any of the claims 15-25, wherein the sealing element is made from a thermal conductive material.

27. Device according to any of the claims 15-26, comprising a heat source connected to the sealing element and / or the pressure element for heating thesealing element and / or the pressure element at least in the sealing position for sealing a flexible film to the folded perimeter wall of the container.

28. Device according to any of the claims 15-27, comprising an adhesive applicator for applying an adhesive to the folded perimeter wall of a container.

Images