APPARATUS AND METHOD FOR FORMING A HERMETIC PACKAGE FOR CREAMY PRODUCTS

A method for forming a package for creamy products including the following steps: the formation of a tray starting from a first piece of wrapping material in such a way as to form a base and a continuous perimeter edge perpendicular to the base; dosing a predetermined quantity of creamy product into the tray formed; forming a lid for closing the upper opening of the tray starting from a second piece of wrapping material and positioning the lid formed in contact with the creamy product; the second piece has a surface for covering the creamy product and a raised perimeter edge extending from the covering surface and positioned to face the perimeter edge of the tray; a sealing of the package by sealing the lid to the tray obtained by partial sealing of the perimeter edges placed side by side of the tray and of the lid to the tray in such a way as to define at least a first perimeter zone of the edges sealed together and at least a second perimeter zone of the edges which are not sealed and communicating with the creamy product contained in the tray; a folding of the facing perimeter edges on the covering surface of the lid; a subsequent step of expelling any air present in the tray by pressing on the creamy product contained in the tray; and lastly a complete sealing of the folded perimeter edges in such a way as to define a complete sealing of the package obtained.

TECHNICAL FIELD

This invention relates to an apparatus and a method for forming a package for creamy products, that is, with a creamy consistency such as products derived from milk, such as cheeses.

BACKGROUND ART

Currently, the sealed packages of creamy products, in particular processed cheese, are of different geometrical types, such as a polygonal solid with a square, rectangular or triangular base, but also with a circular base and are all obtained by a method which comprises:forming a tray starting from a first piece of wrapping material (flat), which is folded in such a way as to define a base and at least one continuous perimeter edge with an extension perpendicular to the base;dosing a predetermined quantity of processed cheese inside the tray;closing the upper opening of the tray with a second piece of wrapping material positioned in contact with the creamy product;folding the free edges of the tray on the second piece; andhot sealing the perimeter edges of the package.

The first and second pieces of wrapping material are made from metal films, such as, for example, aluminium, but the material which can be used may be different even though with properties similar to metal films.

The second piece of wrapping material for closing the tray is currently prepared with two different operational methods.

In a first solution for dosing the tray, the second piece with a flat extension is positioned above the product and inside the tray in such a way that free edges of the tray protrude from the perimeter.

The package is closed by folding the free edges (on the inner side, that is, the one in contact with the processed cheese) of the tray towards the second piece (on the outer side, that is to say, opposite the one in contact with the processed cheese) placed and then sealing the folded edges onto the second piece of covering.

It is understood that during the sealing step, as a consequence also of the type of product, which is semi-liquid and therefore not fully stable during packaging operations, some zones of the edges joining the two components may have folds which are able to form gaps which can generate, once the closure process has been completed, extremely small slits which, when the package is closed, may adversely affect the hermetic seal of the package.

This problem of the absence of a hermetic seal may worsen with the increase in the size of the package to be formed and hence the high perimeter of the closure.

In a second solution for closing the tray (of particular relevance for this invention), the second piece is firstly formed with a base and a continuous perimeter edge perpendicular to the base (in the same way as the tray) and then positioned above the product inside the tray (closing the free opening of the tray) in such a way as to have the edges of the second piece (on the inner side) facing the free edges (on the inner side) of the tray.

At this point, the two facing edges in contact are joined over the entire perimeter by sealing and then folded together towards the inside of the tray.

These packages are made from automatic apparatuses comprising:a station for feeding individual pieces of wrapping material;a hopper for forming the open tray;a conveyor (with a linear or circular path) equipped with a plurality of open cavities or seats in which corresponding open trays are positioned to allow the trays to reach in sequence:a filling station having a device for dispensing the product configured for depositing a predetermined dose of product in the tray;a station for closing the tray comprising a unit for forming and depositing the second piece of wrapping material on the tray, a unit for sealing the edges alongside each other of the tray and of the second piece of wrapping material and a folding unit configured to fold the edges joined so as to adhere to the outer surface of the second piece in such a way as to form the final package.

Although this second solution allows an adequate hermetic seal to be obtained, it does not guarantee an optimum duration of the product in the package if air bubbles are trapped.

AIM OF THE INVENTION

The aim of this invention is to provide an apparatus and a method for forming a package for creamy products, that is to say, with a creamy consistency like products derived from milk, such as cheeses, which overcome the above-mentioned disadvantages of the prior art.

More specifically, the aim of the invention is to provide an apparatus and a method for forming a package for creamy products which is able to reduce the risks of lack of hermetic seal and eliminate, at the same time, the risk of entrapping air in the package.

A further aim of the invention is to provide an apparatus and a method for forming a package for creamy products which is able to maintain a high rate of quality of the finished product combined with a high level of operating flexibility irrespective of the shape of the package.

Said aims are fully achieved by the apparatus and method for forming a package for creamy products according to the invention as characterised in the appended claims.

With reference to the accompanying drawings, in particularFIGS.1to6and9to16, the method according to the invention and the relative apparatus implementing the method are used for forming a package, shown in some of these drawings and labelled1in its entirety, for creamy products, such as, for example, but without limiting the scope of the invention, processed cheese.

As illustrated, the method comprises a step for forming a tray starting from a first piece2of wrapping material (using a first forming device3) folding the first piece2in such a way as to form a base4and a continuous perimeter edge5extending substantially perpendicular to the base4(FIGS.1and9).

The tray is cup-shaped, with an upper opening facing upwards. In a quadrangular configuration, the perimeter edge5is formed by four vertical walls which extend from the base4. The four vertical walls and the base4are formed starting from a single piece2of wrapping material.

Subsequently, the method comprises a step of dosing a predetermined quantity of creamy product P into the tray formed (FIGS.2and10).

The quantity of product dosed into the tray formed is such as to leave, in the upper part, a free perimeter edge5not struck by the creamy product P.

Again as illustrated, the method comprises a step for forming a lid for closing the top opening of the tray starting from a second piece6of wrapping material folding the second piece6in such a way as to define a covering surface and a raised perimeter edge7which extends substantially perpendicular from the covering surface;

The method also comprises a step of inserting the dosing lid into the tray placing the covering surface in contact with the creamy product P positioned in the tray and the raised perimeter edge7of the lid facing the perimeter edge5of the tray (seeFIGS.3,11and12).

In practice, the lid6is made in the same way as the tray.

More specifically, defining as an inner side of the first and second piece the side in contact with the product and the outer side of the first and second piece the side opposite the inner side, the edge7of the lid and the free edge5of the tray have both the relative inner sides facing each other.

The method comprises a step of sealing the package1by sealing the lid to the tray.

As illustrated, the step of sealing the package1comprises the following sub-steps:a partial sealing of the perimeter edges5and7facing each other of the tray and of the lid6in such a way as to define at least a first perimeter zone Z1of the edges5and7sealed to each other and at least a second perimeter zone Z2of the edges5and7not sealed and communicating with the creamy product contained in the tray (seeFIGS.4,7and13and13a).

After the partial sealing step, the method comprises the following sub-steps:

folding the facing (and partly sealed) perimeter edges5and7of the tray and the lid6on the covering surface of the lid (seeFIGS.5and14);

a subsequent step of expelling any air present in the tray by pressing on the product contained in the tray; and lastly

a step of pressing the creamy product P contained in the partly sealed tray for expelling any air present in the tray;

a final sealing of the perimeter edges5and7folded on the covering surface of the lid6in such a way as to obtain a complete sealing of the package1obtained (seeFIGS.6,15and16).

Thanks to this method for forming the package, a package is obtained which has both an optimum seal with consequent better hermetic properties and a package without air bubbles inside it which might adversely affect the life of the product located in the closed package.

Preferably, the sub-step of expelling air and the sub-step of complete sealing are carried out almost simultaneously by means of a single sealing/pressing device9(seeFIG.6).

It should be noted that the edges5and7of the lid6and of the tray may have different heights where they face each other.

In light of this, the step of forming the closing lid6(of the upper opening of the tray) forms a perimeter edge7of the lid6with a height such that when it is rested on the creamy product P inside the tray, it is placed over the perimeter edge5of the tray.

In the case illustrated inFIG.7, the perimeter edge5of the tray has a height, from the covering surface, which is greater than the edge7of the lid6so that, after the step of folding the two edges5,7onto the covering surface of the lid6, an outer portion of the edge5of the tray, on its inner side, that is, the one in contact with the creamy product P, lies in contact with the outer side, that is, the one not in contact with the creamy product P, of the covering surface of the lid6.

Substantially, the free edge of the tray may have a height greater than the edge of the lid6, so, after the step of folding the lid6towards the covering surface, a portion of the free edge (the inner side of it) of the tray comes into contact with the covering surface of the lid (on the outer side of the latter).

FIGS.9to16show a tray and the lid6having a perimeter (more specifically, the corresponding raised edges5and7) which are polygonal in shape (in this case square, but it might also have the shape of a triangle, rectangle, etc.).

With this geometry of the package, the sub-step of partial sealing only occurs close to the corners joining the sides of the raised and facing edges5and7of the tray and lid6.

As illustrated inFIG.8, the package1might have a circular perimeter shape (or ellipsoid shape, depending on production requirements), so the tray and the second piece6have a circular or ellipsoid perimeter (of the corresponding raised edges5and7.

With this geometry, the sub-step of partial sealing occurs along curved, and limited, stretches of the raised and facing edges5and7of the tray and lid6.

Preferably, the curved zones Z1may be alternated in a constant fashion with non-sealed zones Z2(seeFIG.8), but this does not mean that the alternating cannot be differentiated in a constant manner with respect to that illustrated inFIG.8.

It should be noted that the partial sealing sub-step is obtained by sealing (by means of a partial sealing device10) the raised and facing edges5and7of the tray and of the lid6starting from a predetermined height Q relative to the covering surface formed by the lid6resting on the creamy product P (seeFIG.7), so as not to seal the zone between the covering surface and the predetermined height Q.

In light of this, the first partial seal is made at an intermediate height between the upper end of the edge7of the lid6and the corner joining the edge7with the covering surface of the lid6.

Preferably, both the partial sealing sub-step and the complete sealing sub-step are carried out hot and at an operating temperature of not less than 100° C.

Preferably, the sub-step of final sealing of the folded perimeter edges5,7is performed by keeping the creamy product P contained in the tray pressed.

In light of this, the sub-step of pressing the creamy product P contained in the partly sealed tray is performed with a pressure exerted only on the folded perimeter edges5,7on the covering surface of the lid6, leaving a central zone unpressed.

The first piece2and the second piece6are preferably made of material with heat-sealing characteristics. More specifically, at least the inner surface of the first and second pieces2and6are treated with lacquers which are able to give said inner surfaces heat-sealing characteristics.

The invention also comprises an apparatus for forming the package1for creamy products.

As illustrated, the apparatus comprises a first forming device3configured to form a tray by folding a first piece2of wrapping material which is able to define a base4and at least one continuous perimeter edge5extending perpendicular to the base4(FIGS.1and9).

In the case illustrated, by way of example, the device3comprises a forming hopper14located above a conveyor15(with a linear or circular path) equipped with a plurality of open cavities or seats16in which the respective open trays are formed and positioned to allow the trays to reach in sequence the further zones for completing the package1.

The forming of the tray in the hopper14is achieved with a piston17movable along the opening of the hopper14.

The apparatus also comprises an element30(dispensing nozzle) for filling the tray and configured to dispense the creamy product P at a predetermined rate in the tray (FIGS.2and10).

The apparatus comprises a second device11(for example, a second forming hopper18with a relative piston19) configured to form a lid by folding a second piece6of wrapping material and placing the lid thus formed on the creamy product in the tray.

In this way, the lid forms a covering surface lying on the creamy product and a perimeter edge7positioned to face the free perimeter edge5of the tray (FIGS.3and11).

The apparatus also comprises a station12for hermetic sealing of the lid to the tray.

As illustrated, the sealing station12comprises a device10for partial sealing of the facing perimeter edges5and7of the tray and of the lid6configured to perform a sealing of at least one perimeter zone Z1of the edges5and7facing each other.

It should be noted that the first zone Z1covers in its entirety a limited perimeter portion of the facing edges5,7of the tray and of the lid6in such a way as to leave at least a second perimeter zone Z2of the unsealed edges5,7in communication with the creamy product contained in the tray (FIGS.4and13).

Again as illustrated, the sealing station12comprises a folding element8configured to fold the facing perimeter edges5and7of the lid6and of the tray on the covering surface of the lid6. The folding element8is configured to be actuated after the partial sealing has been performed with the partial sealing device10(FIGS.5and14).

Again as illustrated, the sealing station12comprises a pressing device and a device for sealing complete of the folded perimeter edges5and7. The pressing and complete sealing devices being configured so as to be actuated after the folding of the facing perimeter edges5,7of the lid6and of the tray with the folding element8so as to define a complete sealing of the package1obtained (FIGS.6,15and16).

It should be noted that the device10for partial sealing of the opposite perimeter edges5and7of the tray and of the cover6comprises a sealing plate22having a heated discontinuous track (with suitable heating unit23), that is, only predetermined stretches of the track are sealed.

In light of this, the discontinuous track could be equipped with a translation unit22afor moving the heated stretches towards and away from the facing edges5and7. In a first embodiment, the folding unit8comprises a series of walls21which are movable preferably horizontally in both directions to allow the folding of the partly sealed edges5and7.

The pressing device and the complete sealing device comprise a plate29having a continuous track on the heated lower surface to allow the pressing of the product and the complete sealing of the folded edges5and7and the relative sealing of the package.

Preferably, the pressing device and the complete sealing device consist of a shared pressing-sealing device9configured to expel the air from the inside of the tray and completely seal the folded perimeter edges5,7.

In light of this, the pressing-sealing device9is operated in such a way as to perform the complete sealing while the creamy product P contained in the tray is kept pressed.

In a first embodiment, the tray and the lid6may have the perimeter of the corresponding facing edges5and7which are polygonal in shape (square, quadrangular, etc.).

In this case, the partial sealing device10(with a shape matching the shape of the raised edges5and7) is configured in such a way as to perform a partial sealing only in the proximity of the corners of the facing edges5and7of the lid6and of the tray.

It should be noted that if the tray and the lid6have a perimeter of the corresponding facing edges which is circular or ellipsoid, the partial sealing device10has a shape matching the shape of the edges5and7and is configured in such a way as to define a plurality of curved and limited sealed zones Z1, of the facing edges5and7of the tray and lid6.

As illustrated inFIG.8, a circular plate24is equipped with a set of heated semi-circular portions which are translatable towards and away from the facing edges5and7in such a way as to partly seal the facing edges5and7of the tray and of the lid6.

In terms of construction, the partial sealing device10comprises a pair of sealing units configured to be actuated towards each other along a direction parallel to the base4of the tray, whilst the pressing and complete sealing devices are configured to be actuated along a direction perpendicular to the base4of the tray.

Preferably (seeFIGS.13aand13b), the partial sealing device10comprises at least one fixed sealing element30and a sealing element31movable between a position away from the fixed sealing element30and a position close to the fixed sealing element30with the perimeter edges5,7facing the tray and the lid6interposed between them.

The fixed sealing element30is located stationary outside the tray whilst the movable sealing element31is configured to be actuated away from/towards the fixed sealing element30from the inside of the tray.

In light of this, the fixed sealing element30consists of a single element configured to encircle the facing perimeter edges5,7of the tray and of the lid6, whilst the movable sealing element31comprises a plurality of movable sealing elements which are configured to operate in conjunction with the fixed sealing element30and are of a size such as to leave unsealed zones between them when they are close to the fixed sealing element30.

It should be noted that (in an example embodiment of quadrangular packages), the fixed sealing element30is part of a perimeter supporting frame T.

The movable sealing units31may comprise two pairs of plates31aand31bwith angled sealing heads.

Each plate31a,31bhas the corresponding ends tapered to define inclined surfaces32,33complementary to and facing the inclined surfaces33,32of the plates contiguous thereto in order to complete the perimeter configuration of the fixed sealing element30.

The inclined surfaces32,33of the plates31a,31ballow the plates to slide in both directions along trajectories which are also transversal to each other and simultaneously move away from/towards the fixed sealing element30from the inside of the tray.

As mentioned, each plate31aand31has at least two outer side surfaces heated and contiguous and angled to allow the sealing of the corners of the edges5,7, whilst the remaining surfaces are inactive and form only parts of the frame of the plates or the tapered ends.

The packaging method and the relative apparatus structured in this way fully achieve the preset aims thanks to the sealing of the edges alongside each other divided into two steps separate from each other.

The partial sealing step makes it possible to stabilise the reciprocal position of the edges whilst keeping zones of the edges still relatively free or open.

The pressing step allows escape of any air from the inside of the tray and substantially simultaneously the edges are completely sealed with the complete sealing step.

There are advantages with this system such as greater security of internal seal of the package and a linear and compact closure of the entire perimeter edge.