This invention relates to a single-lobe or single-chamber filter bag for infusion products, such as tea, coffee, camomile and the like.
The current market offers many different kinds of filter bags (or tea bags) for infusing the above mentioned products in water.
The wide range of filter bags currently available is the result of the increasingly widespread use and popularity of filter bags among consumers, both in the home and in public places, which has led to a growing demand, especially from product distributors, for diversification of filter bag designs with a view to obtaining filter bags with improved properties in terms of product containment, ease of exchange with the liquid during infusion, shelf life, ease of final packaging, and so on.
The two main designs currently used are the traditional single-lobe bags (usually with tie string and tag) and the now well-established two-lobe bags (also with tie string and tag, with or without individual overwrapper), whose characteristic feature is the larger surface area in contact with the liquid, which allows optimum extraction of the flavour from the infusion product).
Over the years, both these designs have been made from different types of filter paper, including, more recently, biodegradable products.
Similarly, the methods of closing the bag and simultaneously applying the string and tag (in designs where these are present) have been diversified according to production needs and, in some countries, legislative requirements: for example, the tie string, tag and filter bag may be closed and joined by a metal staple, by gluing, by a heat sealable "accessory stamp", by forming a stitch with the tie string itself or by using an adhesive tag.
All of these have improved the quality of filter bags, the processes used to manufacture them (filter bag making machines) and end user satisfaction.
Continuing its policy of product improvement, however, the Applicant has noticed that current filter bags, especially single-lobe bags (which this invention is concerned with in particular) have inherent shortcomings due to their shape which, precisely because they have a single chamber, tend to lack adequate three-dimensional, or volumetric, properties. The resulting disadvantages are that:
Flattening and movement of the filter bags may damage and reduce the overall quality of the product contained. Moreover, it should also be noticed that a loose (that is, single) filter bag will not stand erect for display purposes (during presentation and selection), unlike other types of filter bag, such as tetrahedral or pyramidal bags which, however, are much more expensive than single-lobe bags. In order to improve the stability of the bags, document
However, it is to be noted that the filter bag of
In this regard, it is also known document
Disadvantageously, such known embodiment is very difficult to realize since the folding of the lateral edges needs to be carried out very carefully (i.e. slowly) in order to avoid unaesthetic gibbosities or curls.
For this purpose, the Applicant has created a single-lobe filter bag that overcomes the above mentioned disadvantages and whose structure, besides having the well-known features of customary single-lobe filter bags, is such as to provide a "stiffer" configuration that meets market requirements and, at the same time, improves the overall quality of the infusion and of the filter bag itself.
Accordingly, the invention achieves this purpose by providing a single-lobe filter bag, in particular a single-lobe filter bag for infusion products comprising the technical characteristics described in one or more of the appended claims.
The technical characteristics of the invention, with reference to the above aims, are clearly described in the claims below and its advantages are apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate a preferred embodiment of the invention provided merely by way of example without restricting the scope of the inventive concept, and in which:
With reference to the accompanying drawings, in particular
The filter bag, labelled 1 in its entirety, essentially comprises a length 2 of filter material forming a chamber 3 containing a charge 4 of the infusion product. The length 2 of filter material has a quadrangular shape defined by:
In the filter bag 1, furthermore:
Looking in more detail (with reference to
In a second embodiment (not part of the present invention, see
More specifically, in the first embodiment illustrated in
In the third embodiment (see
According to the invention, the tab 12 is folded and joined stably by a seal S4 to the bottom supporting base 11, thus forming a larger, stiff longitudinal area (see
In the second embodiment illustrated in
Each pair of ends of the second edges 7a and 7b is reciprocally joined by a seal S2 at the respective bottom areas of the connecting sides 8 and 9: this creates a stiff lateral area of the length 2 in order to form wide supporting shoulders for the closed bottom supporting base 11 of the filter bag 1.
In this specific case, the seal S2 is simultaneously made also on the substantially central area of each side 8, 9 in order to also join the latter which, as stated, are initially open, in the configuration in which they are folded towards the inside of the chamber 3.
In addition to the above, the filter bag 1 may be equipped, on the length 2, with a string 13 joined by sealing one end of it to the length 2 itself and the other end to a tag 14 which is in turn removably associated with the length 2 of filter material: this allows correct handling of the filter bag 1 during infusion.
As regards other manufacturing aspects of the filter bag 1, the length 2 of filter material may consist of filter paper or biodegradable material (such as, by way of non limiting example, maize starch) or a non-biodegradable plastic material (such as polyethylene).
The joins on the length 2 of filter material may consist of a first and a second heat seal S1 and S2, that is to say, made by heat sealing.
Alternatively, the two joins may consist of a first and a second seal S1 and S2 made using a suitable glue.
In yet another alternative, the two joins on the length 2 may consist of a first and a second ultrasound seal S1 and S2.
According to one possible variant applicable to all three embodiments described above, the corners 5a and 5b of the first top end 5 of the length 2 are bevelled symmetrically according to an angle α (see
The tubular length 2, having an initially open tubular shape, may, at least in the first two embodiments described above, have a central join for closing the tube and consisting of a third join or seal S3.
In this case, the length 2 of filter material is provided with a string 13 joined, at one end, to the length 2 itself by a knot A1 and, at the other end, to the tag 14 by a knot A2, the string 13 being looped around the length 2 and also around the elastically compliant tab 12 protruding from the bottom supporting base 11.
The tag 14 may also be removably attached, for example by sealing, to the length 2 of filter material.
To keep the tag 14 in position on the length 2, the tag 14 may have a slit 14f made at the top of it for engaging an end portion P of the string 13 knotted to the length 2 of filter material in such a way as to hold it against the length 2.
In both solutions, that is to say, supported by the string 13 or attached to the length 2, the tag 14 is positioned at the top 5 of the length 2 (where the closing seal S1 is located) and protrudes partially from the length 2 itself.
The filter bag 1 illustrated in
A filter bag made as described above therefore achieves the above mentioned purposes thanks to the special forms imparted to the connecting sides and to the bottom edges that close the length of filter material in such a way as to create a flat stiff base that provides: a chamber 3 with a constant volume not only before use, housing the product comfortably and stably, and allowing the filter bag to stand erect on a supporting surface, but also during infusion, allowing the product to move and expand optimally within the chamber, thus guaranteeing an infusion of excellent quality and reduced infusion times.
The invention described above is susceptible of industrial application and may be modified and adapted in several ways without thereby departing from the scope of the inventive concept as defined by the claims. Moreover, all the details of the invention may be substituted by technically equivalent elements.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.