Apparatus and method for forming a hermetic package for creamy products

1. A method for forming a package for creamy products comprising the following steps:

forming a tray starting from a first piece of wrapping material by folding the first piece to form a base and a continuous perimeter edge extending substantially perpendicular to the base;

dosing a predetermined quantity of creamy product inside the tray formed;

forming a lid for closing a top opening of the tray starting from a second piece of wrapping material by folding the second piece to define a covering surface and a raised perimeter edge which extends substantially perpendicular from the covering surface;

inserting the lid into the tray placing the covering surface in contact with the creamy product positioned in the tray and the raised perimeter edge of the lid facing the perimeter edge of the tray;

sealing by sealing the lid to the tray;

wherein the sealing step comprises the following sub-steps:

partially sealing the perimeter edges facing each other of the tray and of the lid to define at least a first perimeter zone of the perimeter edges sealed to each other and at least a second perimeter zone of the perimeter edges not sealed and communicating with the creamy product contained in the tray; after the partially sealing steps:

folding the facing perimeter edges of the tray and the lid on the covering surface of the lid; and lastly

pressing the creamy product contained in the partly sealed tray for expelling any air present in the tray; and

finally sealing the perimeter edges folded on the covering surface of the lid to obtain a complete sealing of the package obtained.

2. The method according to claim 1 , wherein the step of forming the lid forms a perimeter edge of the lid with a height such that when the lid is rested on the creamy product inside the tray, the perimeter edge of the lid is placed over the perimeter edge of the tray.

3. The method according to claim 2 , wherein the perimeter edge of the tray is at a height, above the covering surface, which is greater than the perimeter edge of the lid so that, after the step of folding the two perimeter edges onto the covering surface of the lid, an outer portion of the perimeter edge of the tray, on an inner side in contact with the creamy product, lies in contact with an outer side not in contact with the creamy product, of the covering surface of the lid.

4. The method according claim 1 , wherein the tray and the lid have a perimeter with a polygonal shape and wherein the sub-step of partially sealing occurs only close to corners joining the sides of the raised and facing perimeter edges of the tray and the lid.

5. The method according to claim 1 , wherein the tray and the lid have a circular or ellipsoid shaped perimeter, and wherein the sub-step of partially sealing occurs along curved and limited stretches of the raised and facing perimeter edges of the tray and of the lid.

6. The method according to claim 1 , wherein the sub-step of partially sealing is obtained by sealing the raised and facing perimeter edges of the tray and lid starting from a predetermined height relative to the covering surface of the lid resting on the creamy product, so as not to seal the zone between the covering surface and said predetermined height.

7. The method according to claim 1 , wherein the sub-step of partially sealing and/or the sub-step of finally sealing occurs hot and at an operating temperature of not less than 100° C.

8. The method according to claim 1 , wherein the sub-step of finally sealing of the folded perimeter edges is performed by pressing the creamy product contained in the tray.

9. The method according to claim 1 , wherein the sub-step of pressing the creamy product contained in the partly sealed tray is performed with a pressure exerted only on the folded perimeter edges on the covering surface of the lid, leaving a central zone unpressed.

10. An apparatus for forming a package for creamy products comprising at least:

a first forming device configured to form a tray by folding a first piece of wrapping material which is able to define a base and at least one continuous perimeter edge extending perpendicular to the base;

an element for dispensing a creamy product in the tray and configured to dispense a predetermined dose of the creamy product in the tray;

a second forming device configured to form a lid by folding a second piece of wrapping material and placing the lid on the creamy product located in the tray, said lid defining a covering surface lying on the creamy product and a perimeter edge positioned to face the perimeter edge of the tray;

a station for sealing the lid to the tray;

wherein the sealing station comprises at least:

a partial sealing device for performing a partial sealing the facing perimeter edges of the tray and lid and configured to seal at least one first perimeter zone of the perimeter edges facing each other, said at least one first perimeter zone covering in its entirety a limited perimeter portion of the facing perimeter edges of the tray and of the lid such as to leave at least a second perimeter zone of the unsealed perimeter edges in communication with the creamy product contained in the tray;

a folding element configured for folding the facing perimeter edges of the lid and of the tray on the covering surface of the lid, said folding element being configured to be actuated after the partial sealing with said partial sealing device has been performed;

a pressing device and a complete sealing device for performing a complete sealing of the folded perimeter edges, said pressing and complete sealing devices being configured, respectively, for pressing the creamy product into the tray to expel any air still present in the tray and to completely seal the folded perimeter edges to obtain a sealed package, said pressing and complete sealing devices being configured to be actuated after the folding of the facing perimeter edges of the lid and of the tray with said folding element.

11. The apparatus according to claim 10 , wherein the tray and the lid have a perimeter of the corresponding facing perimeter edges which is polygonal in shape and wherein the partial sealing device is configured to perform the partial sealing only in proximity to corners of the facing perimeter edges of the tray and of the lid.

12. The apparatus according to claim 10 , wherein the pressing device and the complete sealing device consist of a shared pressing-sealing device configured to expel the air from inside of the tray and completely seal the folded perimeter edges, said complete sealing device being actuated to perform the complete sealing while the creamy product contained in the tray is held pressed.

13. The apparatus according to claim 10 , wherein the partial sealing device comprises a pair of sealing units configured to be actuated towards each other along a direction parallel to the base of the tray, whilst said pressing and complete sealing devices are configured to be actuated along a direction perpendicular to the base of the tray.

14. The apparatus according to claim 10 , wherein the partial sealing device comprises at least one fixed sealing element and a movable sealing element movable between a position away from the fixed sealing element and a position close to the fixed sealing element with interposed the facing perimeter edges of the tray and of the lid, the fixed sealing element positioned stationary outside the tray, while the movable sealing element is configured to be actuated away from/towards the fixed sealing element from inside of the tray.

15. The apparatus according to claim 14 , wherein the fixed sealing element consists of a single element configured to encircle the facing perimeter edges of the tray and of the lid, while the movable sealing element comprises a plurality of movable sealing elements which are configured to operate in conjunction with the fixed sealing element and are of a size to leave unsealed zones between the movable sealing elements when the movable sealing elements are close to the fixed sealing element.