EP1726525A1

EP1726525A1 - Method and apparatus for sealing containers

Info

Publication number: EP1726525A1
Application number: EP05425372A
Authority: EP
Inventors: Mauro Biondi Compagnoni
Original assignee: Guerra SpA
Current assignee: Guerra SpA
Priority date: 2005-05-26
Filing date: 2005-05-26
Publication date: 2006-11-29

Abstract

A method for sealing containers and the like by application of a protective film (100) at a mouth (20) of a container (30) to be sealed, comprising a step of fixing the film (100) onto the edge of the mouth (20) and a step of forming that occurs by exerting a pressure onto the film (100) at the mouth (20), such as to cause a permanent sinking (110) on the film (100) internal to the container (30).

Description

The present invention relates to a method and an apparatus for sealing containers and the like.
More specifically, this invention relates to the field of the hermetic closure of containers by application of a protective film at a mouth thereof
A prolonged preservation and a safer protection of products subject to drying when put into contact with air, or anyhow to contamination, spilling and alteration of their physico-chemical properties if not properly shielded from the outside environment, are certainly desirable in view of the remarkable saving attainable thereby.
Moreover, the ever stricter hygiene standards passed on the preservation and storage of food products - naturally perishable - or generally of products with features such as to call for an adequate isolation thereof from the outside environment make ever more pressing the need to optimise the sealing power of the containers intended to contain such typologies of products or materials.
Accordingly, finding systems for subjecting the containers to a really effective sealing ensuring a hermetic closure thereof is of primary importance.
For this purpose, it has e.g. been developed and is in use a combined sealing system envisaging, besides the application of lids or caps as is common practice, a preliminary and additional procedure of filming the mouth of the containers.
Therefore, the sealing process is integrated with a step of applying a protective film, lids or caps being then overlapped thereto in order to reinforce its seal and provide greater mechanical strength.
However, the combined sealing systems implemented with the current technologies entail drawbacks, the main one among them lying in that the previous step of filming does not allow the use of all shapes of lids or caps.
In particular, the protective film applied to the mouth of the containers does not allow a subsequent closure by lids or caps having a portion of the covering surface sunken with respect to the edges of the mouth of the containers themselves.
Lids or caps with a shape such as to have, once applied, a covering surface sunken with respect to the edges of the mouth of the container involved are currently used, e.g. in the field of manufacturing of food containers or of paint cans.
The particular shape of such lids or caps gives a good sealing capacity to the coupling with the edges of the containers.
In the case at issue, the depth of engagement, e.g. by fitting in, of the peripheral portion of such lids or caps with the edges of the containers, attainable thanks to said specific shape, ensures a closure with a strong seal.
However, the joint application of a protective film and of lids or caps having a structure with said shape is not allowed when operating with the conventional machineries used to date.
In fact, a covering surface of the lids or caps sunken with respect to the edges of the mouth of the container involved would cause the rupture of the protective film previously fixed to the edges of the mouth.
On the other hand, the plane lids or caps not incorporating such a sinking of the covering surface do not prove as sealing, and, though compatible with the applying of a protective film, are anyhow a compromise solution.
To date, the known art is not aware of a method for sealing containers and the like allowing the joint application of a protective film and, thereabove, of a lid or cap with good sealing capacity by virtue of a specific shape having a covering surface sunken with respect to the edges of the mouth of the container to which it is to be applied; nor is it aware of a machinery capable of implementing such a method.
Hence, object of the present invention is to solve said problems, by proposing a sealing method and a sealing apparatus for containers and the like as defined in claim 1 and in claim 7, respectively.
The sealing method according to the present invention constitutes a process optimizing the capacity for hermetic closure of containers and the like.
In particular, the sealing method according to the present invention allows to apply a protective film at a mouth of a container to be sealed, and concomitantly to use lids or caps shaped so as to have, in the operating configuration when closing said container, a covering surface sunken with respect to the edges of the mouth of the container itself.
Thus, there can advantageously be exploited the good sealing capacities of said typology of lids and caps, also benefiting by the joint additional protection offered by a protective film.
Of course, the sealing method according to the present invention is perfectly compatible with a closure of the containers carried out with conventional lids or caps having a plane covering surface, e.g. in case only these are in stock or a saving on supply costs is desired.
Thanks to their versatility, the sealing method and apparatus according to the present invention can advantageously and economically be adapted to any container typology and shape.
Advantageously, the adoption of a method according to the present invention allows to attain an effective sealing of containers through the carrying out of a sequence of simple steps.
The apparatus according to the present invention, apt to carry out such a sequence of steps, is of easy manufacture and installation by virtue of a linear structure and an operation marked by utmost rationality.
Further advantages, as well as the features and the modes of employ of the present invention will be made apparent by the following detailed description of an embodiment thereof, given by way of a non-limiting example, making reference to the figures of the annexed drawings, wherein:

figure 1 is an exploded perspective view depicting some components of a sealing station of the apparatus for sealing containers and the like according to a preferred embodiment of the present invention, operating on the basis of the method for sealing containers and the like according to the present invention,

figure 1A is a front view of a detail of the fixing member of the apparatus of figure 1;
figure 1B is a perspective view of a detail of the shearing means of the apparatus of figure 1;
figure 2 is a perspective view of the sealing station components depicted in figure 1, when in the assembled configuration;
figure 3 is a sectional view of the components of figure 2
figures 4A, 4B and 4C are front views illustrating three subsequent steps of the operation of the sealing station of the apparatus of figure 1;
figure 5 is a top plan view of means for removing a portion of protective film left over from shearing and of means for providing an intact portion of protective film for the sealing station of the apparatus of figure 1;
figure 6 is a front view of the apparatus according to the present invention, apt to illustrate the succession of two subsequent containers at the sealing station of the apparatus of figure 1;
figure 7 is a front view illustrating the passage of a container from the sealing station to a station for sterilizing the apparatus of figure 1; and
figure 8 is a perspective view of a container sealed by the application of a protective film as provided by the method according to the present invention.

To describe a preferred embodiment of the present invention, hereinafter reference will be made to the above-indicated figures.
In the figures, an apparatus for sealing containers and the like by the application of a protective film 100 at a mouth 20 of a container 30 to be sealed generally comprises a sealing station and a station for sterilizing the air head comprised between the protective film 100 and a product optionally contained by the container 30.
A sealing station for an apparatus according to the present invention comprises a member 1 for fixing the protective film 100 onto the edge 21 of the mouth 20 of the container 30 to be sealed.
Such a fixing member 1, e.g. basically disc-shaped, is preferably connected to means 10 for the vertical translation thereof, e.g. ram-shaped, apt to make it movable between a top position A detached from the mouth 20 of the container 30 and a bottom position B of contact with the edge 21 of the mouth 20.
The modes of fixing the film 100 onto the edge 21 of the mouth 20 of the container 30 can be plural and envisage different variants, all falling within the protective scope defined for the present invention.
In figure 1A it is highlighted how the fixing member 1 may incorporate resistors 4 for heat-sealing the film 100.
The sealing station also comprises means 2 for forming the film 100 at the mouth 20.
The forming means 2, positioned at the bottom of the fixing member 1, is apt to exert a pressure onto the film 100 such as to cause a permanent sinking 110 on the film 100 internal to the container 30.
Said means 2 comprises a forming member 2 that, with regard to the hereto-illustrated embodiment of the apparatus according to the present invention, is basically disc-shaped.
Preferably, such a forming member 2 is made integral to the fixing member 1 and it is dimensioned so as to pass through the mouth 20 of the container 30; thus the forming occurs concomitantly to the lowering of the fixing member 1 to the bottom position B of contact with the edge 21 of the mouth and during its permanence in said position B.
A sealing station for an apparatus according to the present invention further comprises means 3 for shearing the film 100, acting onto the film 100 externally to the periphery of the mouth 20 of the container 30.
Such means for shearing the film 100 is made, e.g., by a blade 3 circumferentially arranged about the fixing member 1, preferably heated by Joule effect via a resistor arranged into contact with the blade 3 itself.
The blade 3 can be made integral to the fixing member 1, and mounted coaxial thereto, so that the descent of the fixing member 1 into position B results in the concomitant carrying out of the shearing of the protective film 100 externally to the periphery of the mouth 20 of the container 30.
Thus, the fixing member 1, the forming member 2 and the shearing means 3 define, once assembled, a sealing head 500.
With reference to Figure 5 and 6, the apparatus according to the present invention further comprises means 200 for removing the portion 101 of film 100 left over from said shearing step, as well as means 210 for supplying an intact portion 102 of protective film 100.
Thanks to said supplying means 210, the intact portion 102 can be made available so as to allow its application onto the mouth 20 of a further container 30b taking the place in the sealing station of a previous container 30a already subjected to filming.
Such removing and supplying means may comprise a take-up reel 200 and a roll system 210.
Said means is in charge of the rewinding of the left-over portion 101 of the film 100 and of the positioning and tensioning of the intact portion 102 of the film 100.
The configuration of the apparatus is such that the roll system 210, e.g. comprising two rolls having parallel axis of rotation and being arranged at the same height above the container 30 with respect to the conveyor belt 300, keeps the film 100 tensioned and ready for the application onto the edge 21 of the underlying container 30.
With reference to the application disclosed here, the take-up reel 200 is located in a position raised with respect to one of the rolls 210 and such as to ease the rewinding without tearing of the left-over portion 101 of the film 100.
The vertical translation means 10, apt to carry out the joint descent of the fixing member 1, the forming means 2 and the shearing means 3 for the filming of the container 30, is located in a position basically equidistant from the rolls 210 and anyhow basically true with respect to the surface of the intact portion 102 of the film 100.
The container 30 can be brought at the sealing station of the apparatus according to the present invention by means of a moving mechanism, e.g. automatic, like a conveyor belt 300.
Likewise, once the sealing has occurred, the container 30 can be transferred by means of the moving mechanism to the next sterilizing station.
The station for sterilizing the apparatus according to the present invention is apt to disinfect an air head 50 comprised between the film 100 and a product contained in the container. For this purpose, the sterilizing station may comprise means 70 for emitting germicidal radiations 60, e.g. UV-ray lamps.
With reference to the foregoing, hereinafter it will be described the operation of the embodiment of the apparatus according to the present invention examined here.
As it can be verified in figure 4A, the film 100 is fed to the sealing station and tensioned between the rolls 210a and 210 b.
The rotation of the rolls 210a and 210b causes the same feed of the film 100.
Preferably, at least one of the rolls 210a or 210b is dragged in rotation by motorized actuating means.
A container 30 is located at the sealing station by the moving mechanism 300.
Upon arranging between the rolls 210 an intact portion 102 of film 100, basically flush with the mouth 20 of the container 30, a control unit, e.g. programmable by a user, commands the activation of vertical translation means 10.
Such vertical translation means 10 brings the sealing head 500 from a top position A where the fixing member 1 is detached from the mouth 20 of the underlying container 30 to a bottom position B where the fixing member 1 is into contact with the edge 21 of the mouth 20.
Consequently to the lowering of the fixing member 1 to the bottom position B of contact with the edge 21 of the mouth 20 of the container 30, the forming member 2 comes to press against the intact portion 102 of the protective film 100.
The value of the pressure exerted by the forming member 2 is calibrated so as not to cause the perforation of the protective film 100, merely inducing a progressive deformation thereof until the fixing member 1 adjoins the edge 21 of the mouth 20 of the container 30.
Such a deformation process goes on along the whole permanence of the fixing member 1 in said position B.
By virtue of the physico-chemical features of the (preferably plastic) material used, and of the value of the load applied, the deformation induced onto the protective film 100 is of a permanent kind.
In particular, the forming member is shaped so as to induce a permanent sinking 110 in the intact portion 102 of protective film, entering through the mouth 20 of the container 30.
When the fixing member 1 lands on the edges 21 of the mouth 20 of the container 30, after the expelling of air in excess inside the container 30 as a consequence of the full passing of the forming member 2 through said mouth, there starts the process of fixing the protective film 100 to the container.
In the case of the embodiment given here, such a fixing process occurs by heat-sealing, thanks to the heat developed by the resistors 4, incorporated in the fixing member and heated by Joule effect when power-supplied.
Said heat propagates through the conductive structure of the fixing member 1, until spreading onto the surface area of the fixing member 1 intended to come into contact with the container 30.
The shearing process at the periphery of the mouth of the container 30 carried out by the blade 3 can it also occur through an alike heating by Joule effect of a resistor arranged into contact with the blade 3.
The dimensioning of the fixing member 1 and of the blade 3, as well as their relative positioning, will be such that the shearing occurs only after the fixing step has been completed, thereby not compromising the success thereof and ensuring the perfect adhesion of the film onto the edge 21.
When also the shearing step has been completed, the rising of the sealing head 500 is commanded again, until the fixing member gets to position A.
Then, the left-over film portion 101 is rewound about a reel 200, e.g. motorized. The left-over film portion 101 is depicted in the top view of figure 5, in which there can be seen a void left by the film portion applied to the container 30.
The rewinding occurs so as to preserve the continuity of the film 100, which is advanced until an intact portion 102 of film useful to the filming of a subsequent container is repositioned between the rolls 210.
As it is evident from figure 6, once a container 30a has been filmed, the conveyor belt 300 leads to the filming station a subsequent container 30b so that the latter be subjected to the same process.
The filmed container 30a is in turn led from the conveyor belt 300 to the sterilizing station, as illustrated in figure 7.
At this stage, there are subjected to sterilization the air head 50 comprised between the permanent sinking 110 of the film 100, created at the preceding sealing station, and a product contained by the container 30a.
In the case at issue, germicidal UV radiations are emitted by lamps 70 at the opening mouth 20 of the container 30a.
The access to the sealing and sterilizing stations can be regulated, e.g., by a sensor system along the moving path, so as to optimize the continuity of the production cycle, e.g. providing that when the sterilizing step to which the container 30a is subjected has ended, the fully filmed container 30b be ready to take the place of the container 30a onto the sterilizing station.
To the above-described method and apparatus for sealing containers and the like by application of a protective film a person skilled in the art, in order to satisfy further and contingent needs, may effect several further modifications and variants, all however falling within the protective scope of the present invention, as defined by the appended claims.

Claims

A method for sealing containers and the like by application of a protective film (100) at a mouth (20) of a container (30) to be sealed, comprising a step of fixing said film (100) onto the edge of said mouth (20) and a step of forming that occurs by exerting a pressure onto the film (100) at said mouth (20), such as to cause a permanent sinking (110) on the film (100) internal to the container (30).
The method according to claim 1, further comprising a step of shearing said film (100) at the periphery of said mouth (20) of said container (30), said shearing occurring subsequently to said fixing.
The method according to claim 2, wherein said step of shearing occurs through heating by Joule effect.
The method according to one of the claims 1 to 3, wherein the fixing of said film (100) onto the edge (21) of said mouth (20) occurs by heat-sealing.
The method according to one of the claims 1 to 4, comprising a step of sterilizing an air head (50) comprised between said permanent sinking (110) of said film (100) and a product contained in said container (30).
The method according to claim 5, wherein said sterilizing step occurs by emission of germicidal radiations (60).
An apparatus for sealing containers and the like by the application of a protective film (100) at a mouth (20) of a container (30) to be sealed, comprising a sealing station comprising:
- a member (1) for fixing said film (100) onto the edge (21) of said mouth (20);

- means (2) for forming said film (100) at said mouth (20), positioned at the bottom of said fixing member (1), apt to exert a pressure on said film (100) such as to cause a permanent sinking (110) of the film (100) internal to said container (30).
The apparatus according to claim 9, further comprising means (3) for shearing said film (100) acting onto the film (100) externally to the periphery of said mouth (20) of said container (30).
The apparatus according to claim 8, comprising means (200) for removing the portion (101) of said film (100) left over from said shearing and means (210) for supplying an intact portion (102) of said film (100) for a new application at the mouth (20) of a further container (30b) to be sealed, operating by rewinding of the left-over portion of said film (100), positioning and tensioning (210) of the intact portion (102) of said film (100) and comprising a roll system (210) and a take-up reel (200).
The apparatus according to claim 7, wherein said fixing member (1) incorporates resistors (4) for the heat-sealing of said film (100).
The apparatus according to claim 7, wherein said fixing member (1) is movable between a top position (A) detached from said mouth (20) of said container (30) and a bottom position (B) of contact with the edge (21) of said mouth (20), in which it is carried out the fixing of said film (100) onto the edge (21) of said mouth (20), being connected to means (10) for the vertical translation (10) thereof.
The apparatus according to claim 11, wherein said fixing member (1) is basically disc-shaped.
The apparatus according to claim 7, wherein said forming means comprises a forming member (2) basically disc-shaped, made integral to said fixing member (1) and dimensioned so as to pass trough said mouth (20).
The apparatus according to claim 8, wherein said shearing means comprises a blade (3) circumferentially arranged about said fixing member (1).
The apparatus according to claim 14, wherein the blade (3) is heated by Joule effect via a resistor arranged into contact with said blade (3).
The apparatus according to claim 14, wherein said blade (3) is integral and coaxial to said fixing member (1).
The apparatus according to one of the claims 7 to 16, comprising a station for sterilizing an air head (50) comprised between said permanent sinking (110) of said film (100) and a product contained in said container.
The apparatus according to claim 17, wherein said sterilizing station comprises means (70) for emitting germicidal radiations (60).