Apparatus and method for working plastic material and container for fluid product
The invention relates to apparatus and method for producing containers by working plastic material, the containers being arranged for containing a fluid product.
Containers are known obtained by thermo-forming a sheet material, for example a film of plastic material, arranged for containing a fluid or semi-fluid product, which 'may be poured through a suitable pouring outlet of the container. These containers are opened by removing therefrom an end portion of container so as to obtain an opening in said containers.
These containers have a drawback consisting in that once they have been opened they can not be closed again and therefore an undesired pouring may take place, so causing a certain consumption of said product. Furthermore, outflow of product may cause soiling of parts of the body and/or clothes of a user as well as of the region surrounding the container. International patent application WO 95/12531 discloses a container suitable for being closed again, comprising a container body arranged for containing a fluid product and a self-closing valve arranged for allowing said product to be poured, once the container has been opened, only when a pressure is applied by a user on the walls of -the container body.
In particular, the aforesaid patent application discloses a first version of container comprising a valve in which a first film and a second film define a duct through which the product is distributed. The first film constitutes a hemispherical dome facing the second film, which, on the contrary, is substantially undeformed so as to form a substantially flat portion. During pouring, the fluid product may flow out from the container passing through the duct defined between the hemispherical dome and the underlying flat portion. After pouring, the user has to deform the hemispherical dome, substantially flattening it, by applying on the hemispherical dome a slight pressure in order to bring the 'first film in contact with the second film, so causing the duct to be closed. _ '
Therefore, the container described in WO 95/12531 can not be closed again without intervention of the user. International patent application WO 95/12531 further discloses a second version of container in which the distribution valve is provided with a pipe suitable for allowing the product to flow out, said pipe being defined by a first film and a second film which, as previously described, in a distributing position, are arranged so as to constitute, respectively, a dome and a flat portion. In a closing position, on the contrary, the first film may be deformed so that the dome, having initially a convex profile towards the outside of the container, constitutes a concave portion which may be received into a suitable recess obtained from a simultaneously deformation of the second film.
In this manner, the valve hermetically closes the container, so preventing the product from being distributed even in the case in which a certain pressure is applied on the walls of the container body. I International patent application WO 99/10252 discloses a container obtained by thermoforming a sheet material and comprising a closing valve arranged for allowing the product contained in the container to be poured in a partial and deferred manner. The container comprises a lower, relatively thick, film having a shaped profile so as to define a container body and an upper film thinner than the lower film and arranged in substantially flat position. The lower film and the upper film are welded along the border of the container. At one end of the shaped film there is a region comprising a plurality of recesses mutually separated by protuberances arranged therebetween. The upper film and the protuberance cooperate for forming the closing valve preventing the product contained in the container from being distributed when no force acts on the aforesaid container body.
Working of the valve is substantially based on the deformability of the upper sheet: in fact, once the pressure which caused pouring of the product is finished, the upper sheet is forced to penetrate, at least partially, into each one of the recesses, so being in contact with the protuberances arranged therebetween and thus preventing the product from f rther flowing out . A drawback of the above mentioned containers is that their production is very complicated.
Obtaining substantially hemispherical recesses and domes is, in fact, quite difficult and may remarkably compromise the productivity of the plants arranged for producing such containers. Furthermore, in case of containers made with a .pair of films having different thickness, problems can take place connected to differences of thermal expansions which make problematic coupling the films. An object of the invention is to improve containers obtained by thermoforming and provided with a controlling valve for distributing a product contained therein.
A further object of the invention is to obtain a thermoformed container in which a valve may be easily obtained suitable for effectively controlling the flow of product through a distributing pipe.
A further object of the invention is to obtain an apparatus and a method for producing thermoformed containers provided with a controlling valve for distributing a .fluid product contained therein. In a first aspect of the invention, a container is provided preferably obtained by thermoforming a first film and a second film of thermoformable material, comprising container body means arranged for containing a fluid product and pipe means arranged for controlling distribution of said product from said container, characterized in that said pipe means defines a non-rectilinear path for said product along progressively decreasing sections of said pipe means. In an advantageous version, the first film defines a first concave portion of said pipe means, whereas the second film may define a second concave portion of said pipe means extending internally to said first portion.
In a second aspect of the present invention, a container is provided, comprising container body means arranged for containing a fluid product and pipe means arranged for controlling distribution of said product from said container, characterized in that, said pipe means comprises a first concave portion and a second concave portion, said second concave portion extending internally to said'first concave portion.
Owing to these aspects of the invention, it is possible to obtain a container provided with pipe means which define valve means suitable for controlling outflow of a fluid product. The pipe means preferably define a curvilinear path along which, at the end of the distribution of the product, a small bubble of air is sucked back from the external environment into the container; such bubble of air is trapped between the pipe means so opposing undesired outflows of product. Furthermore, as the pipe means has a section having a very little surface extension and the fluid product flows with friction on the walls of said pipe means, pouring is very difficult, if not absolutely prevented, even in case in which the air bubble has penetrated into the container body means and therefore does not further oppose the passage of the product through the pipe means.
It has been verified that the pipe means according to the invention prevents dripping or loss of product even in case of highly fluid product.
Since the liquid outflow inhibiting effect is not due to contact between the two films constituting the valve means, but is achieved by forming pipe means sufficiently narrow and having walls which are constantly separated by a pre- established distance, it is not necessary to use film of different thickness, and in particular thin films, in order to have high deformability.
That allows to remarkably simplify the producing process since film of any thickness may be used, particularly films having thickness equal to each other, which may be simultaneously thermoformed by means of a single apparatus .
In a third aspect of the invention, an apparatus for producing containers is provided, comprising thermoforming means arranged for thermoforming first film means and second film means of thermoformable material for obtaining said containers, characterized in that said thermoforming means comprises forming mould means arranged for obtaining into said containers pipe means having a non-rectilinear I path suitable for inhibiting undesired outflows of product after opening. In a fourth aspect of the present invention, an apparatus for producing containers is provided, comprising thermoforming means arranged for thermoforming thermoformable sheet material for obtaining said containers, characterized . in that said thermoforming means comprises forming mould means provided with a protruding element arranged for deforming said thermoformable sheet material.
In an advantageous version, the thermoforming mould means comprises first half-mould means provided with at least one cavity arranged for deforming the first film in order to obtain a first concave portion of said pipe means, and preferably, second half-mould means provided with at least a protruding element arranged for deforming the second film in order to obtain a second concave portion of said pipe means, said second concave portion extending internally to said at least one cavity.
Owing to this aspect of the invention, it is possible to obtain an apparatus allowing to effectively produce containers provided with pipe means acting also as distributing valve arranged for controlling outflow of a fluid product from said containers. Such apparatus is suitable for simultaneously working a pair of films of any thickness by thermo-welding and thermoforming said films in order to obtain the desired containers. In a fifth aspect of the invention, a method for producing containers is provided, comprising thermoforming thermoformable sheet material for defining in said containers container body means arranged for containing a . fluid product and pipe means arranged for controlling distribution of said product from said containers, characterized in that said thermoforming comprises defining in said pipe means a non- rectilinear path suitable for inhibiting undesired outflows of product after opening. In an advantageous version, said defining comprises obtaining in the pipe means a first concave portion and a second concave portion of said sheet material extending into said first concave portion.
Owing to this aspect of the invention, it is possible to obtain a method for producing containers provided with pipe means acting also as distributing valve arranged for controlling outflow of a fluid product from said containers. The invention may be better understood and carried out with reference to the enclosed drawings, which show some exemplifying and not limiting embodiments thereof;, in which: Figure 1 is a sketched view taken along a vertical plane of a pre-heating station, of a welding station and of a forming station of an apparatus according to the invention;
Figure 2 is a front view of the welding and forming stations of Figure 1 in which respectively a welding half-mould and a forming half-mould have been removed;
Figure 3 is a detail sectioned along a vertical and broken plane of a welding mould of the apparatus according to the invention; Figure 4 is a detail sectioned along a vertical plane of a forming mould of the apparatus according to the invention;
Figure 5 is a front view of a container according to the invention;
Figure 6 is a side view of a container according to the invention;
Figure 7 is an enlarged and sectioned detail of distributing valve means of a container according to the invention;
Figure 8 is an enlarged and sectioned detail as that of Figure
7, showing a variation. With reference to Figures 1 to 4, an apparatus 1 for producing containers 2 is shown suitable for distributing in a controlled manner a product 3 contained therein..
The apparatus 1 comprises a plurality of stations through which a first film 4 and a second film 5 of thermo-formable material are indexed along an advancing direction shown by the arrow F, said first film 4 and second film 5 being progressively unwound from a not shown reel.
The above-mentioned stations comprise a pre-heating station 6 in which heating means βa, 6b, 6c soften the film so prearranging the film for the next stages of the working cycle.
Downstream of the pre-heating station 6, a welding station 7 is provided in which welding mould means 8 comprising a first welding half-mould 8a and a second welding half-mould 8b, movable so as to be able to mutually approach and move away, as shown by the arrows FI and F2, interact with the first film
4 and the second film 5 in order to obtain therefrom a plurality of pre-forms 9 of containers welded along respective peripheral edges.
Downstream of the welding station 7, a forming station 10 is arranged comprising forming mould means 11 provided with a first forming half-mould 11a and a second forming half-mould lib arranged for tightening on the pre-forms 9, being moved along the direction shown by the arrows F3 and F4, in order to form the containers 2.
Downstream of the forming station 10, a filling station, not t shown, is provided, in which the product 3 is introduced into the containers 2. Finally, downstream of the filling station, a sealing station, not shown, is provided in which the containers 2, filled with the product 3, are sealed; a separating station, not shown, is also provided in which the filled and sealed containers 2 are separated from the undeformed portions of the first film 4 and the second film 5, which keep the containers 2 mutually joined.
As shown in Figure 2, pipe means 12 is obtained in the welding mould means 8 and in the forming mould means 11, suitable for allowing a forming fluid to be introduced into the welding mould means 8 and the forming mould means 11 through an inlet 12a.
In particular, the forming fluid, when introduced into the welding mould means 8, causes slight deformations of the first film 4 and the second film 5, so allowing to obtain the pre- forms 9; this is achieved owing to the limited depth of the cavities 8c with which the first half-mould 8a and the second half-mould 8b are provided.
In the forming mould means 11, on the contrary, the forming fluid blows the pre-forms 9 until bringing the first film 4 and the second film 5 in contact with the walls of the cavities lie, lid of the forming mould means 11', so obtaining the finished containers 2.
As shown in Figure 4, the first forming half-mould 11a and the second forming half-mould lib have respectively a shaped region 13 and a further shaped region 13a, arranged for forming distributing valve means 14 in the containers 2. The first forming half-mould 11a comprises a region 13 having substantially the shape of a truncated cone, whereas the second forming half-mould lib comprises initially a region 13a having the shape of a cylinder and then a protruding element 19 suitable for forming in said distributing valve means 14 a suitable narrowing of the internal section of the distributing valve means 14. With reference to Figures 5 to 7, a container 2 is shown comprising a container body 2a suitable for receiving a fluid product 3 and distributing valve means 14' arranged for controlling outflow of the fluid 3 from the container 2, in particular for preventing the product 3 from being poured from the container 2 when no external pressure is applied on the walls of the body 2a.
The distributing valve means 14 comprises pipe means 15 obtained by properly deforming the first film 4 and the second film 5 so as to give a "S"-like shape to the pipe means. Thus, the pipe means 15 comprises in succession, a first curved portion 25 and a second curved portion 26, the first curved portion and said second curved portion having respective centres of curvature CI, C2 placed at opposite sides of said pipe means 15. Such pipe means 15 has a decreasing section departing from the body 2a and defines a curvilinear path 21 for the fluid 3. The pipe means 15 comprises outflow preventing means 16 for the fluid 3 comprising capillary means 17i • obtained by remarkably reducing the section of the distributing valve means 14 at its end section.
The pipe means 15 is crossed by opening indicating means 23 consisting for example of a preferred notching or cutting line along which the container may be opened by tearing, or by removing a strip 24 of the container, so allowing outflow of product 3 from the pipe means 15.
Such reduction of the section of the pipe means '15 is obtained by deforming the second film 5 so as to obtain a concave portion 18 extending into a respective concave portion 20 obtained from said first film 4. The concave portion 18 has a substantially dome-shaped profile so as to define capillary means 17 extending along the above-mentioned curvilinear path 21. The capillary means 17 is therefore obtained by reducing the distance between the first film 4 and the second film 5, which, however, never lie in mutual contact.
The outflow preventing means 16 works according to the principles described hereinafter: first of all when a user releases the body 2a, at the end of the distribution of the product 3, a suction effect takes place which causes a bubble of air of limited dimension to be trapped in the curvilinear path 21, defined by the capillary means 17, so preventing outflow of further product 3. If the aforesaid bubble of air, being attracted by the vacuum pressure present in the container 2, penetrates into the body 2a, • clearing the capillary means 17, the fluid 3 starts to flow towards the outside of the container 2 without being able to reach the outside as it is kept by friction on the walls of the capillary means 17 until any further advancing is prevented.
The length and the area of the capillary means 17 may be varied according to the viscosity of the product 2, so allowing the outflow preventing means 16, to perform effectively the function of controlling distribution of product having viscosity belonging to a wide range.
As shown in Figure 8, the curvilinear path 21 may also have, in a portion thereof extending towards the outlet of the container, a region 22 in which a widening of section takes place.