Package making – Methods – Forming or partial forming a receptacle and subsequent filling
Reexamination Certificate
1999-06-17
2001-04-17
Kim, Eugene (Department: 3721)
Package making
Methods
Forming or partial forming a receptacle and subsequent filling
C493S920000, C493S931000
Reexamination Certificate
active
06216426
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bag for packaging liquid formed using a film of plastic, comprising a leaktight chamber for the liquid and a pocket, adjacent to this chamber, in which a pipe for withdrawing the liquid is housed, means being provided to give access to the inside of the said pocket, an opening being formed through part of the wall of this pocket, adjacent to the said chamber, to allow the said withdrawing pipe to enter the said chamber in a leaktight fashion. This invention also relates to a method for the manufacture of bags and for packaging liquid continuously in these bags.
2. Description of the Prior Art
There has already been proposed, especially in WO 95/23742, a bag for packaging liquid comprising an incorporated valve for controlling the outlet of liquid and which can be manufactured continuously from a film of thermoplastic. It has been proposed that a drinking straw be associated with this bag to allow the liquid to be accessed through the valve that consists of a passage formed between two layers of film which normally touch and which open when the drinking straw is inserted. Thus, when the drinking straw is withdrawn at least partially from the passage that forms the valve, this passage closes back up and the liquid can no longer get out. The drawback with this system lies in the fact that by withdrawing the drinking straw, this straw makes liquid in the passage of the valve come out, gradually soiling the outside of the bag.
Clearly it is not easy to make an effective seal in this kind of bag, even less so when this bag is equipped with a valve of the aforementioned type. The edges of the passage delimiting the valve are made by welding together films of thermoplastic. Now, by welding these films together, the structure of the substance of the film is locally altered and the film becomes amorphous and loses some of its elasticity, so detracting from the quality of seal that can be formed. The use of an element added on to the inlet end of this valve-forming passage is also precluded. This clearly demonstrates the complexity of the problem to be solved, it being necessary for the solution to be appropriate to the very low cost price that can be tolerated for a bag of this type. Other problems associated with this design of bag, and the solutions to which are combined and re-used in the present invention, have already been provided by the inventor of the present invention and have been covered by other protections. These in particular include the question of incorporating a drinking straw into the bag, and the tamper-proofing of this bag for obvious health and safety reasons.
By contrast, the problems associated with sealing and with a certain method of manufacture and of packaging the liquid continuously had hitherto not yet been dealt with satisfactorily. One of these problems is associated with incorporating a drinking straw into a closed pocket of the packaging in a manufacturing process that uses a material in the form of continuous strip.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is specifically to provide a solution to the problem of sealing, and to that of manufacturing bags and packaging liquid continuously in such bags, allowing in particular the use of known designs of machine even if these machines need after all to be converted substantially so that they can be adapted to the manufacture and packaging of these bags.
Thus the subject of the present invention is first of all a bag for packaging liquid of the aforementioned type as defined in Claim
1
. This tubular element of decreasing section is obtained by stretching out a plastic film and thus allows the film to maintain its elasticity which guarantees effective sealing. What is more, this is a very simple solution perfectly suited to the product for which it is intended.
As a preference, the wall of the pocket containing the said withdrawing pipe is secured to a tab cut from one layer of film intended to form the leaktight chamber. This tab makes it possible to guarantee that the access to the drinking straw which acts as a pipe for dispensing the liquid has not been tampered with.
Advantageously, the opening formed at the end of the tubular element forming the seal communicates with one end of a passage forming a valve between this opening and the inside of the leaktight chamber, the pocket of the bag being formed between a first layer of film forming one of the walls of the said passage and a second layer of film which is appreciably narrower than the first layer and secured to the tab for opening the pocket. Thanks to this arrangement, a saving of one thickness of film is made because one of the walls of the pocket is formed by one of the films of the valve passage. This saving in thickness has an advantage when the strip of part-finished bags has to be wound onto a reel to be sent to a liquid-packaging unit. The added thickness consisting of two thicknesses of film forming the walls of the pocket can thus be reduced by half, also reducing the difference in thickness from one edge of the reel of part-finished bags to the other.
As an alternative, this pocket may however be formed in the fold of a film folded on itself. As a preference, this fold may lie adjacent to one end of the passage controlling the flow of the liquid and the tubular element forming the seal may extend over part of this passage.
Another subject of this invention is a method for the manufacture of bags and for the packaging of liquid continuously in these bags according to claim
9
. One of the advantages of this method is that it allows the bags to be filled and the straws to be inserted laterally, one of the longitudinal edges of the material in strip form intended to form one of the edges of these bags remaining open until the time of filling. Thus the drinking straw can be inserted laterally along the axis of the seal and of the valve passage when there is this passage, and a liquid-supply pipe can be slipped between the walls of the bag, along its edge that coincides with the longitudinal edge of the material in strip form. This longitudinal edge is welded up as the material in strip form progresses, just before filling.
Advantageously, the method takes place in two separate phases, one consisting in forming a continuous strip of part-finished bags, and the second consisting in forming the tubular seal, in inserting the withdrawing pipe therein and in packaging the liquid in the chamber. The advantage of this method of production is that it allows the part-finished bags to be manufactured and the liquid to be packaged in two separate production units, the packager of the product not necessarily being called upon to solve the problems involved in the manufacture of a bag of this kind.
Thus the packager of liquid into the packaging can then use the part-finished bags thus produced just like simple sheets or films used for packaging liquid in sachets, bags or cartons, carrying out the packaging using conventional machinery, so that in order to package the liquid he wishes to sell in the bags according to the invention, especially bags with valves, all the liquid packager needs to do is replace the customary sheet materials or simple extruded films with the part-finished bags according to the present invention.
One of the main advantages of the chamber that is the subject of the invention is that there is a film seal over the valve passage and this means that by piercing this film seal, not by cutting it, but by a point deformation of the film seal towards the valve passage until it bursts, an annular seal which is slightly conical is obtained and guarantees elastic clamping of the drinking straw, giving a seal that makes it possible to prevent any liquid in the valve passage from escaping.
In addition, the two faces of the chamber which come from the same sheet folded onto itself do not become o
Carapak Braintrust NV
Henderson & Sturm LLP
Kim Eugene
LandOfFree
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