EP0686574A1

EP0686574A1 - Filter-bag for infusion products, e.g. tea

Info

Publication number: EP0686574A1
Application number: EP95108354A
Authority: EP
Inventors: Calogero Daunisi
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-06-09
Filing date: 1995-05-31
Publication date: 1995-12-13
Also published as: ITBO940272A1; ITBO940272A0

Abstract

The filter-bag for infusion products comprises a tubular element made of a filtering material that cannot be subjected to thermal bonding and in which at least one median transverse folding line is formed and is adapted to define a first lobe (3) and a second lobe (4) that are meant to contain respective doses of an infusion product. The lobes (3,4) are folded together in packaging position and are rigidly closed by folding at an angle the corners (5) that correspond to the opposite ends of the tubular element, so as to form a trapezoidal profile, and by subsequently folding an end flap (6) of the first lobe (3) over the corresponding edge of the second lobe (4). A handling string (7) made of natural fiber is rigidly coupled, at one end (7a), to the folded flap (6) of the lobes by means of a seam (8) for closing the lobes with natural fiber thread, and a label (9) is fixed at the free end of the handling string.

Description

The present invention relates to a filter-bag for infusion products.
Various kinds of filter-bag for infusion products, such as tea, camomile, and the like, are known; they contain a single dose of product that must be immersed, at the time of use, in a suitable vessel containing boiling liquid. These filter-bags are usually obtained from a tubular element made of filtering material which is appropriately closed at its ends.
In particular, filter-bags with two lobes have long become widespread; the lobes are formed by transversely folding the tubular element in half, conveniently so that when the filtering material cannot be subjected to thermal bonding, a sort of accordion-like fold forms on the bottom of the bag; sometimes, when the filtering material can be subjected to thermal bonding, said lobes are furthermore hermetically separated by means of one or two transverse bonding lines at the bottom and at the folding line. The two lobes are meant to contain respective doses of the infusion product, so as to increase the contact surface of said product with the liquid and thus obtain a better infusion.
In the prior art, filter-bags of the above mentioned type are manufactured according to different methods which obviously require the use of suitable machines for packaging and filling; in any case, they have contraindications and drawbacks for various reasons.
More specifically, a known method for manufacturing said filter-bags entails forming individual elements from a roll of filtering material, for example filter paper that can be subjected to thermal bonding, each element being meant to form a bag. Said elements are folded in half and then along their lateral edges to form the bag which, after filling, is folded on the last side as well.
A second known method entails folding said roll of filter paper longitudinally and forming thereon a series of transverse bondings that are meant to delimit the individual bags. Said bags are separated from each other after filling them and closing the last side.
In a similar manner, starting from a roll of filter paper that is folded longitudinally so as to form said tubular element, it is possible to obtain the individual elements that are meant to form respective filter-bags with two lobes.
A known bag of the above mentioned type entails that the opposite ends of the tubular element, after overlapping the two lobes, be folded so as to form a trapezoidal or pagoda-like shape, so as to close and couple said lobes to each other.
The filter-bag is sometimes closed by means of a staple or clip made of aluminum, which also retains one end of a cotton string that bears a label at the other end. The string, of course, allows to dip the filter-bag in the boiling infusion liquid and to remove it therefrom.
According to a different known solution, the filter-bags are joined by means of an aluminum staple to a continuous string carrying fixed thereon alternatively to said bags respective labels. The string is subsequently cut so as to form individual packages.
The metal clip or staple that closes the bag entails several drawbacks and contraindications, mainly owing to the fact that the aluminum alloy has minor components that can easily oxidize, so that in the course of time the aluminum staple tends to oxidize and, in contact with the boiling infusion water, releases oxidized microparticles into it, microparticles that are then unwittingly ingested by the consumer.
Furthermore, during infusion the staple may inadvertently separate from the filter-bag, fall into the beverage, and then be ingested with it.
Furthermore, if the infusion is prepared directly inside a microwave oven, there is also the risk that the metal staple might melt.
In another known solution, the string is fixed to the opposite ends of the tubular element, which is made of filter paper that can be subjected to thermal bonding and forms the two overlapping lobes, by means of respective thermoplastic tags, so as to wrap longitudinally around the outside surface of the bag; one of said thermoplastic tags also retains the label against the surface of a corresponding lobe and retains the edge of the opposite lobe, which protrudes slightly with respect to the edge of the other lobe for this purpose. During use, the pulling of the label allows to separate the corresponding thermoplastic tag from the bag, so as to release the string. In the configuration for use, the two lobes of the bag are therefore divaricated.
The bag according to this other solution also has various drawbacks and contraindications. First of all, the bag is considerably expensive because the filter paper can be subjected to thermal bonding, and therefore has a higher weight per unit surface than normal filter paper, and because of the excessive cost of the two thermoplastic tags for fixing the string to the label and to the bag.
Secondly, the very fact that the filter paper can be subjected to thermal bonding, that is to say, that it has a layer of adhesive material for thermal bonding, and the fact that, to allow its adhesive layer to firmly fix the string to the bag, said tag must be subjected to thermal bonding at temperatures above 100^oC, entails that the package is not free from the risk of contaminating the beverage, since the heat-activated adhesive layers, during infusion, remain in direct contact with the boiling water.
The aim of the present invention is to obviate the above mentioned drawbacks by providing a filter-bag for infusion products that is simple to manufacture, has a relatively low cost, and allows in particular to eliminate the above mentioned risks and dangers and to ensure optimum ecological characteristics as regards the product that is offered and the consumer's protection.
Within the scope of this aim, another object of the present invention is to provide a filter-bag for infusion products that is simple in concept, easy to use, and assuredly functional.
This aim and this object are achieved, according to the invention, by the present filter-bag for infusion products, which is characterized in that it comprises: a tubular element made of a filtering material that cannot be subjected to thermal bonding and in which at least one median transverse folding line is formed, said line being adapted to define a first lobe and a second lobe meant to contain respective doses of an infusion product, said lobes being folded together in packaging position and being rigidly closed by folding at an angle the corners corresponding to the opposite ends of said tubular element, so as to form a trapezoidal profile, and subsequently fold an end flap of said first lobe over the corresponding edge of said second lobe; a handling string made of natural fiber rigidly coupled, at one end, to said folded flap of said lobes, by means of a seam for closing said lobes with natural fiber thread; and a label fixed at the free end of said handling string.
The details of the invention will become apparent from the detailed description of preferred embodiments of the filter-bag for infusion products, illustrated only by way of non-limitative example in the accompanying drawing sheets, wherein:

figure 1 is a perspective view of the filter-bag according to the invention;
figure 2 is a similar perspective view of a different embodiment of the filter-bag;
figure 3 is a view of the filter-bag of figure 1 during a step of the stitching of said string.

With particular reference to the above figures, the numeral 1 designates a filter-bag obtained from a tubular element made of a filtering material that cannot be subjected to thermal bonding, for example filter paper. The tubular element is formed, in a known manner, by joining the longitudinal edges of an appropriately folded sheet of said material; said joining is provided for example by folding and then scoring the sheet edges along the median longitudinal axis.
A joining line 2 is formed transversely by cold-scoring in a median position on said tubular element. It is conveniently possible to provide two adjacent joining lines 2.
The transverse joining lines 2 are adapted to form a first lobe and a second lobe, designated by the reference numerals 3 and 4 respectively, that are meant to contain respective doses of an infusion product, for example tea and the like. It should be noted that the first lobe 3 has slightly larger longitudinal dimensions than the second lobe 4.
In practice, the lobes 3 and 4 of the bag are meant to be folded together by folding the tubular element transversely at the axis that lies in an intermediate region between the joining lines 2.
The overlapping lobes 3 and 4 are closed hermetically, at the opposite ends of the tubular element, by folding the corners 5 of the bag in a pagoda-like shape and by subsequently folding an end flap 6 of the first lobe 3 over the edge of the second lobe 4. The folding of the flap 6 partially affects the corners 5.
A cotton string 7 is arranged along the median longitudinal axis of the tubular element and wraps around the bag 1.
The string 7 is fixed to the bag, at its opposite ends, by means of a seam 8 formed at the folded flap 6 and with a cotton thread. The seam 8 obviously closes the lobes 3 and 4 of the bag in addition to coupling them to each other.
A conventional label 9 is fixed to the thread 7 proximate to one end. Said label 9 is preferably folded over the thread 7 and is rigidly coupled to it by means of a spot of glue 10.
The bag thus produced is preferably packaged inside a corresponding envelope, not shown in the drawing. During use, the filter-bag is removed from said envelope. By means of suitable traction, the label 9 is then released, separating the end of the string 7 that is adjacent to said label from the seam 8. When the bag is to be used, the string 7 can therefore extend to its full length and remains joined to the package only at one end 7a. The string 7 allows to handle the filter-bag for immersion in the boiling infusion liquid and removal therefrom.
The fact should be stressed that the end 7a of the handling string 7 is stably fixed to the filter-bag, since it wraps around the edge of the folded flap 6 and therefore on both sides of the bag and is retained by the seam 8 on both sides of the bag, whereit is folded back.
The free end of the string 7, which is adjacent to the label 9, can instead be extracted easily from the seam 8 since it is retained only on one side of the bag.
Figure 2 is a view of a different embodiment of the filter-bag, in which the label 9 fully covers the free end of the string 7. The label 9 is partially inserted, in its packaging configuration, below the folded corners 5 and flap 6. Of course, in this case the label 9 is removed from its seat at the time of use.
Of course, the label 9, instead of being folded back, that is to say, instead of being double as in figure 1, can also be single, and instead of being rigidly coupled to the string 7 with a spot of glue 10, it can be self-adhesive or can be fixed by means of a metal staple or of a seam formed with thread.
The string 7, instead of being wrapped around the bag 1 and being arranged along the longitudinally median axis of said tubular element, can furthermore be arranged adjacent to the bag in any manner.
The lobes 3 and 4 of the filter-bag can furthermore be separated by means of an accordion-like fold 11 formed transversely to the tubular element instead of by the scored lines 2.
As shown in figure 3, the seam 8 of the handling string 7 is preferably formed by means of a conventional sewing machine, of the type with an oscillating crochet spool tip, such as those used to attach buttons and the like. In this machine, an oscillating hook 13, commonly termed "crochet", cooperates with the needle 12 and is adapted to grip a loop formed by the sewing thread 14; said loop is formed in the ascending stroke of the needle 12 and is then crossed by said needle 12 during descent. The stitch thus formed is generally termed "chain-stitch".
Conveniently, the seam 8 is formed by means of a series of stitches, preferably at least six. It should be noted that for the sake of clarity in the drawing, the holes formed by said stitches have been shown as if they were separate; actually, said stitches substantially coincide, so that only two holes pass through the filter paper. The holes are formed with needles having a diameter of a few tenths of a millimeter, so that the stitching holes do not remain on the bag. The number of stitches that form the seam is related to the size of the thread, to the speed of the machine, and to the weight per unit surface of the filter paper.
To conclude, the described filter-bag achieves in an optimum manner the functionality and low-cost requirements typical of this type of products. In particular, the absence of metal staples or of thermoplastic tags for fixing the thread to the bag and to the label, and the use of normal filter paper that cannot be subjected to thermal bonding allow savings in material and avoid unnecessary additional costs.
The fact should also be stressed that the filter-bag is closed without the aid of metal staples or thermoplastic or heat-activated adhesive materials. The lobes for containing the product are in fact formed exclusively by means of folds in the filter-paper element and are closed by means of said seam formed with natural-fiber thread.
Accordingly, the filter-bag according to the invention, used in the most disparate manners (with boiling water, with hot water, in microwave ovens) does not entail the danger of finding thermoplastic pollutants or metal oxide particles in the infusion, to the detriment of the consumer.
The filter-bag, which nonetheless preserves its practicality in handling as regards its use, therefore has exclusive ecological characteristics that have never before been achieved in the specific field and, for the protection of the consumer, compliance with the most demanding food safety and quality requirements of the offered product is ensured.
In the practical embodiment of the invention, the materials employed, as well as the shape and the dimensions, may be any according to the requirements.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A filter-bag for infusion products, characterized in that it comprises: a tubular element made of a filtering material that cannot be subjected to thermal bonding and in which at least one median transverse folding line (2) is formed, said line being adapted to define a first lobe (3) and a second lobe (4) adapted to contain respective doses of an infusion product, said lobes (3,4) being folded together in packaging position and being jointly closed by folding at an angle the corners (5) that correspond to the opposite ends of said tubular element, so as to form a trapezoidal profile, and by subsequently folding an end flap (6) of said first lobe (3) over a corresponding edge of said second lobe (4); a handling string (7) made of natural fiber that is rigidly coupled, at one end (7a), to said folded flap (6) of said lobes (3,4), by means of a seam (8) for closing said lobes with natural-fiber thread; and a label (9) that is fixed at the free end of said handling string (7).
A bag according to claim 1, characterized in that said end (7a) of the handling string (7) that is rigidly coupled to said folded flap (6) of said lobes (3,4) wraps around the edge of said folded flap (6) and is retained by said seam (8) on both sides of said bag.
A bag according to claim 1, characterized in that said free end of the handling string proximate to which said label (9) is fixed is retained by said seam (8) on said folded flap (6) of said lobes (3,4) and can be separated by pulling said label at the time of use.
A bag according to claim 1, characterized in that said label is adapted to fully cover said free end of the handling string (7) and to be partially inserted, in said packaging position, below said folded corners (5) and said folded flap (6).
A bag according to claim 1, characterized in that said seam (8) is formed by means of a sewing machine of the type with an oscillating "crochet" spool tip (13), which is adapted to form a plurality of stitches passing through said lobes (3,4), which are folded together at said end flap (6).
A bag according to claim 1, characterized in that said natural-fiber handling string (7) is arranged along a longitudinally median axis of said tubular element, so as to wrap around said bag in said packaging position.
A bag according to claim 1, characterized in that two joining lines (2) are arranged adjacent to said median folding line, are formed by cold-scoring, and are adapted respectively to close said lobes (3,4) at the base.
A bag according to claim 1, characterized in that said lobes (3,4) are separated by means of an accordion-like fold (11) that is formed transversely to said tubular element.