The present invention relates to a device for opening flexible containers.
It is well known that drinks for human consumption, in particular fruit juices and dietary complements, are ever more frequently sold and preserved inside flexible containers, commonly called “pouches”.
Specifically, such containers comprise a flexible pouch, generally made of polyethylene, and a spout, able to allow the outflow of the product preserved within the container.
The outflow of the product is made particularly convenient by the possibility of exerting an adequate pressure on the drink, squeezing the pouch.
Flexible containers, or pouches, are obtained from a pair of polyethylene sheets peripherally sealed to each other and having an inlet adapted to allow the filling of the container with the desired drink.
In correspondence with the aforesaid inlet is inserted and secured, by sealing, a portion of the spout. In particular, said sealing operation involves the edges of said inlet and is performed by heating means which cause a partial melting of the edges themselves, causing them to adhere to the portion of the spout inserted into the pouch.
The insertion of the spout into said inlet takes place before the container is filled.
A particularly acute problem in the pouch filling sector concerns the opening of the pouches, to allow the insertion of the spout.
The opening of the flexible containers is particularly difficult because the polyethylene sheets tend to adhere to each other, by effect of their reduced thickness and of electrostatic attraction.
This problem has been confronted and partially solved by the apparatus disclosed in the document U.S. Pat. No. 4,182,094, in which a plurality of suction cups are used to open a flexible container.
Specifically, three suction cups are located on a movable head, whilst a pair of suction cups is positioned and buried within a support plane.
The flexible container is interposed between the suction cups installed on the movable head and the suction cups buried within the support plane.
The suction cups present on the movable head are set side by side and mutually aligned, so that two lateral suction cups and a central suction cups can be identified. In particular, the central suction cup is of the bellows type and its grip plane can thus move rearwards relative to the grip plane defined by the remaining pair of suction cups, allowing a flexion of the container which favours the entry of air into the container, thereby facilitating its opening.
The apparatus summarily described above has the important drawback that it does not operate continuously, but it is an apparatus in which the containers to be treated are fed at successive time intervals. Moreover, the arrangement of the suction cups shown in said apparatus is absolutely not adaptable to an apparatus with continuous feeding of the containers, especially to an apparatus in which the containers to be treated are positioned on a rotary carrousel.
Secondly, the flexion of the pouches during the opening phase is strongly conditioned by the efficiency of the bellows suction cup. If said suction cup does not effectively adhere to the pouch, the latter is not able to flex to such an extent as to allow the entry of a sufficient quantity of air to allow its opening.