GB2369095A

GB2369095A - An infusion package

Info

Publication number: GB2369095A
Application number: GB0127356A
Authority: GB
Inventors: Guy Harrison
Original assignee: Tetley GB Ltd
Current assignee: Tetley GB Ltd
Priority date: 2000-11-14
Filing date: 2001-11-14
Publication date: 2002-05-22
Anticipated expiration: 2021-11-14
Also published as: GB2369095B; GB0027766D0; GB0127356D0

Abstract

An infusion package comprises a chamber formed from one or two pieces of porous material 3,4, wherein at least one pleat 6,7 is formed in at least one of the panels 3,4 of the infusion package 1 thus allowing the infusion package 1 to be packaged flat and to expand on immersion in hot water. The longitudinally extending outer edge of the pleat 8,9 lies inside and spaced apart from the outer edge 5 of the infusion package 1. The infusion package preferably comprises two panels 3,4 where each panel includes at least one, preferably two pleats 6,7. The pleat(s) is preferably in the form of a box pleat and the infusion package is preferably spherical in shape.

Description

Infusion Package

The present invention relates to infusion packages, such as tea and coffee bags.

Infusion packages such as tea and coffee bags are well-known in the art and are typically substantially flat packages formed from one or two pieces of porous material sealed together to form an infusion containing chamber having two panels enclosing an infusible substance. The packages are commonly rectangular or circular.

Substantially flat infusion packages are used because their being flat facilitates, for example, manufacture of the packages, packaging of the resultant product, and allows a neater presentation to the end consumer.

However, it is becoming increasingly desirable to provide infusion packages that can adopt a three-dimensional shape during infusion. Such packages are believed to have consumer appeal. They may also improve infusion performance, as a more three-dimensional shape allows a greater circulation and mixing of the infusing liquid around and into contact with the infusible material, by allowing the infusible material more freedom to move within the package during infusion. Such faster and more efficient infusion can, for example, allow a particular level of infusion to be achieved in a shorter time.

A difficulty with three-dimensional infusion packages is that they typically will not lie substantially flat, and are therefore less efficient for packing and handling, etc., and can present a less attractive appearance to the end consumer. An example of this is a tetrahedral infusion package, which although adopting a more three-dimensional shape on

infusion, will not neatly lie flat prior to use.

There is therefore a desire to provide an infusion package that is substantially flat prior to use for packing purposes, but which will adopt a more three-dimensional shape when infusing. There have been a number of previous proposals for such infusion packages.

For example, GB-A-2337738 describes a substantially flat infusion package that has a pleat or gusset along one side to allow some, relatively limited, expansion of the package during infusion.

EP-A-0811562 describes infusion packages that are said to swell to approximate a spherical shape on infusion. These packages are made from three (or more) identically shaped separate pieces of porous material that are appropriately sealed to each other around the entire periphery of their margins, to form a package effectively having three (or more)"flaps"arranged about a central axis. The Applicants have found that while this infusion package design does allow some swelling of the package during infusion towards a three-dimensional shape, in practice the swelling action is not particularly effective and tends to collapse after the initial expansion.

It is therefore an object of the present invention to provide an infusion package design that has a relatively flat shape prior to use, but which will expand on infusion to a more three-dimensional shape.

According to a first aspect of the present invention, there is provided an infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, wherein at least one of the panels of the chamber has at least one pleat in it, thereby permitting expansion of that panel, with the longitudinally extending outer edge of the pleat lying inside and spaced apart from the outer periphery of the chamber, and the arrangement

being such that the chamber can swell to an expanded volume when immersed in a hot liquid.

The infusion package of the present invention thus includes a pleat in at least one of the panels of its infusion-containing chamber to allow for expansion upon infusion, as in the known expanding infusion packages.

However, the outer (i. e. exposed) edge of the pleat is arranged to lie inboard of the outer sides of the infusion-containing chamber of the package.

The arrangement of the present invention has been found to provide better expansion of the package in use.

It is believed that this may be because the effect of the arrangement of the present invention is that the two facing panel surfaces formed by the pleat (i. e. extending on each side of the inner (concealed) edge of the pleat) in the present invention have different surface areas and therefore do not completely overlie each other. This contrasts with the known arrangements in, for example, GB-A-2337738 and EP-A-0811562, in which the pleat or folded pieces effectively extend right to the outer edge of the package, such that the inner, facing surfaces formed by the pleat have the same surface area and overlap completely.

The Applicants believe that the material on each side of the inner edge of the pleat may effectively try to expand into the same volume as the chamber swells, and must therefore expand towards and past the material forming the opposing inner surface of the pleat. By arranging the pleat such that the facing surfaces formed by the pleat have different surface areas and do not completely overlie each other, part of the volume into which the pleated material has to expand in use is effectively left open. It is believed that this may allow the pleated material to expand into the"open" volume more freely. The pleated material itself may therefore cause less restriction of the expansion than in the known arrangements in, for example, EP-A-0811562.

Thus, according to a second aspect of the present invention, there is provided an infusion package comprising an infusion containing chamber formed from one or two pieces of porous material, in which at least one of the panels of the chamber includes a pleat to allow for expansion of that panel, the arrangement being such that the chamber can swell to an expanded volume upon immersion in a hot liquid; wherein the pleated panel is arranged such that the facing surfaces of the panel extending from the inner edge of the pleat have different surface areas.

The present invention thus provides a better expansion operation in use, but the use of a pleat still allows the package to lie substantially flat prior to use.

The infusion containing chamber in the infusion package of the present invention is formed from one or two pieces of porous material, such as appropriately perforated paper, as is known in the art. The chamber will typically have two panels of porous material, as is usual in infusion packages, although it could have more panels if desired. Where the chamber has two panels, for example, each panel may be formed from a different piece of porous material, or the two panels could be formed by a single piece of porous material which is folded appropriately, as is known in the art.

In one preferred embodiment of the present invention, all, i. e. typically both, the panels of the infusion containing chamber include at least one pleat in accordance with the present invention. In another particularly preferred embodiment, only one panel of the infusion containing chamber contains a pleat (or pleats), with the other panels not being pleated at all.

In such an arrangement, where the chamber has two panels, one panel would be pleated and the other panel would not be pleated.

The overall number of pleats in the panel or panels

of the infusion containing chamber can be selected as desired, but a preferred arrangement comprises (two) such pleats in one panel, and, where appropriate, most preferably two such pleats in each of the two panels of the infusion containing chamber. In a particularly preferred embodiment one panel (and where appropriate preferably each panel) includes two pleats arranged on opposing sides of a centre line of the panel. These arrangements have been found to give particularly good expansion to a stable three-dimensional shape.

The pleat or each pleat preferably runs along the length of the chamber, and preferably substantially right to the ends of the chamber, i. e. for the full length of the chamber (but the pleats will not extend, as discussed above, across the full width of the chamber). Thus, the inner and outer longitudinal edges of a given, and preferably of each, pleat preferably extend lengthwise along the panel, and most preferably are substantially parallel to each other. In one preferred embodiment the longitudinal edges of the pleat (and preferably of each pleat) are substantially parallel to the lengthwise axis of the chamber. In an alternative preferred embodiment the longitudinal edges of the pleat (and preferably of each pleat) are not parallel to the lengthwise axis of the chamber but lie at an angle to it. In this arrangement the pleats preferably lie at around or at 150 to the lengthwise axis of the chamber, although they can be at a greater or lesser angle to it if desired. It is believed that having the pleats lie at an angle to the lengthwise axis of the chamber can have manufacturing advantages.

The end edges of the pleats (which will be shorter) can. be arranged as desired. They can also lie inwardly of the outer periphery of the chamber, but preferably follow its profile, as that may be more convenient and aesthetically pleasing. Thus, the pleat or pleats preferably run along the outer edge of the chamber to

the position of their outer longitudinal edge, which edge then extends across the chamber to the other end edge of the pleat, which end edge then again runs along the outer edge of the chamber.

Each pleat is preferably arranged in a similar manner, save for its overall positioning on the package, to each of the other pleats in the package.

Most preferably the pleat arrangement is symmetrical about a longitudinal axis lying between the pleats. Most preferably the pleats in a panel, and preferably in each panel where appropriate, are arranged symmetrically about a central longitudinal axis of that panel. In a particularly preferred embodiment where the chamber has two panels, the pleats in the two panels of the infusion containing chamber are arranged symmetrically across the common plane in which the panels lie.

The positioning and size of the pleat or pleats will be governed by the shape and size desired for the expanded chamber and generally speaking their size and positions should be chosen accordingly to accommodate and provide enough material to achieve the desired expanded shape. The overall arrangement should be such that the chamber can adopt a substantially flat form prior to use but will upon immersion for infusion in a hot infusing liquid expand in volume. Most preferably the chamber will swell to a particular three-dimensio--l shape such as a sphere, hemisphere or a rugby-ball shape. It is particularly preferred for the chamber establish and retain a relatively stable three-dimensional shape upon infusion that will not tend to collapse in use after it has initially expanded.

For example, although the outer edge of the pleat or pleats arranged in accordance with the present invention should lie within and be spaced apart from the outer periphery of the chamber, their actual position can vary and will depend, for example, on the desired

expansion effect. Moving the edge of a pleat closer to the outer periphery of the chamber may tend to cause greater restriction on the expansion of the package in use, and so may impair the expansion performance, but will allow more material for that expanded part of the chamber. On the other hand, having a larger spacing from the outer periphery may allow freer and better expansion, but will provide less material for expansion.

To take account of this it is generally preferred where more material for expansion is required to include more pleats to provide the extra material and to space these pleats further from the outer edge of the chamber, rather than to move the outer edges of the pleats closer to the outer edge of the chamber.

Generally speaking, having the, and preferably each, pleat extend out to approximately 50% of the distance from the central axis of the chamber (and/or the central axis between the pleats) to the outer periphery of the chamber at the chamber's widest point along that axis has been found to be a preferred arrangement. In another preferred arrangement, each pleat preferably extends out to no more than 25% of the distance from the central axis of the chamber (and/or the central axis between the pleats) to the outer periphery of the chamber at the chamber's widest point along that axis.

The inner edge or edges of the pleat or pleats can be positioned as desired, but most preferably run along or very close to a longitudinal axis lying (preferably centrally) between the pleats, such as the central longitudinal axis of the chamber (where appropriate), as this is more convenient and provides good expansion performance.

In such an arrangement, an infusion package in accordance with the present invention can then be looked upon as having three (or more, if more than one pleat is provided) flaps each extending from a (preferably

central) longitudinal axis, but with the flap (s) formed by the pleat (s) having a reduced width as compared to another flap or flaps of the package.

Thus according to a third aspect of the present invention, there is provided an infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, and in which the panels of the chamber are arranged to form three or more flaps extending from a central axis, with at least one of the flaps having a reduced width as compared to another of the flaps, the arrangement being such that the chamber can swell to an expanded volume upon immersion in a hot liquid.

In a particularly preferred embodiment of this arrangement, there would be two flaps having equal widths formed by the outer edges of the chamber and one or more reduced width flaps formed by the pleat or pleats in the panel or panels. Thus where a panel has two pleats in it, there would be two reduced width fla (preferably both of the same reduced width). In the preferred arrangement having two panels and in which both panels each have two pleats, there would be four reduced width flaps, again preferably all of the same reduced width. In this arrangement the chamber would then comprise six flaps, with four flaps having the same reduced width and two flaps having the same, but greater width.

It is believed that the use of a six"flap" arrangement may be advantageous in its own right, as providing a better expansion arrangement. Thus, according to a fourth aspect of the present invention, there is provided an infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, and in which the panels of the chamber are arranged such that the chamber effectively comprises six flaps extending around a central axis, the arrangement being such that the

package can swell to an expanded volume upon immersion in a hot liquid.

It will be appreciated from the above that a preferred arrangement for the pleat or pleats in the panels is for them to be substantially rectangular in shape (save for possibly at the longitudinal ends of the pleat depending on the shape of the outer periphery of the chamber), i. e. such that the facing inner surfaces formed by the pleat are of a similar length (subject to the shape of the periphery of the chamber), but with one surface having a greater width than the other (since the pleat does not extend widthwise to the outer periphery of the chamber).

In such an arrangement where a given panel has two such pleat arrangements in it, the effect is then to provide a box pleat in that panel. This has been found to provide good expansion in use.

Thus, according to a fifth aspect of the present invention, there is provided an infusion package comprising an infusion-containing chamber formed from one or two pieces of porous material, wherein at least one of the panels of the chamber has a box pleat arranged in it whose outer edges lie inboard of the outer periphery of the chamber, whereby that panel may expand, the arrangement being such that the chamber will swell to an expanded volume upon immersion in a hot liquid.

In this arrangement one panel only or both or all the panels of the package may include such a box pleat.

In the infusion package of the present invention, the edges of the pleats and the outer edges of the chamber preferably all come together substantially at the-same point or position at each longitudinal end of the chamber. This has been found to help the chamber to "lock"in its expanded three-dimensional shape after it expand during infusion, and to prevent the chamber collapsing after it has swelled, as the edges tend to

interlock at the apices of the chamber.

The overall outer shape of the periphery of the panels of the bag and hence of the chamber in its flat form can be selected as desired. They could for example be rectangular. In one particularly preferred embodiment the chamber is elliptical in its flat configuration, and, preferably, the outer periphery of each panel has an elliptical or substantially elliptical shape. This has been found to provide a better design for achieving a suitable three-dimensional shape when the chamber expands. Where the chamber has such an elliptical shape, the outer edges of the pleats preferably are still substantially straight and not curved (save for where they lie along the outer edge of the chamber at each longitudinal end of the pleat).

The Applicants have found in particular that a design of infusion package having two panels, with each panel having two pleats in accordance with the present invention, and the panels having an outer elliptical shape, will expand to form a substantially spherical shape upon immersion in a hot infusing liquid. In a particularly preferred such arrangement, the outer shape of the chamber when the package is lain flat has a length of approximately 3 r and a maximum width of approximately 1.5 r (in both cases excluding the sealed margins of the chamber), with the outer edge of each pleat lying approximately 0.5 r from the central axis of the chamber: this should provide a sphere of radius r when expanded.

Thus according to a sixth aspect of the present invention, there is provided an infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, and wherein one or more of the panels of the chamber includes a pleat to allow expansion of that panel, the arrangement being such that the chamber can swell to a substantially spherical shape upon immersion in a hot

liquid.

In another preferred embodiment, the infusion containing chamber is circular in its flat configuration and, preferably, the outer periphery of each panel is circular or substantially circular in shape. In this arrangement, the package preferably has two panels, with only one of the panels having two pleats in accordance with the present invention (the other panel being unpleated). The outer edges of the pleats preferably lie approximately 0.2 to 0.25 r from a central axis of the chamber (where r is the radius of the chamber including any margin seals of the chamber). This package expands to an approximately hemispherical shape.

The piece or pieces of porous material forming the infusion containing chamber should be sealed appropriately to form an enclosed chamber, as is known in the art. The entire outer periphery of the chamber may be sealed, or the piece or pieces of porous material making up the chamber may be partially folded (where, for example, the chamber is formed by folding one piece of porous material together, as is known in the art).

The outer edges of the pleats may also be sealed (i. e. the inner surfaces of the pleat at that point sealed to each other) if desired, and this will have to be done where that is necessary to close properly the chamber, e. g. at the longitudinal end edges of the pleated section of the panels. However, the outer longitudinal edges of the pleats are preferably formed substantially, and preferably as far as possible, by means of an (unsealed) fold in the panels (i. e. in the relevant piece of porous material). By forming the pleat from a fold in this manner, the package can expand more freely as a simple fold can be more easily opened out as the panel expands. With a sealed edge, the sealing will restrict the extent to which the pleat can open out and lie flat at that point.

Thus according to a seventh aspect of the present

invention, there is provided an infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, wherein one or more of the panels of the chamber includes a pleat, thereby allowing expansion of that panel, and wherein the outer edge of one or more of the pleats in the panels is formed by folding the panel to form that edge and the panel is not otherwise sealed along that folded edge.

The inner edges of the pleats are also preferably formed by folding (save for any sealing that may be necessary at their longitudinal ends).

The infusion package of the present invention is particularly suited to the design of single-chamber infusion packages, although the techniques of the present invention could be applied to multi-chambered, e. g. dual-chambered, infusion packages if desired to provide such a package with one or more expanding chambers.

The present invention is applicable to infusion packages generally, but it is envisaged that it will have greatest application in relation to infusion packages for the preparation of beverages, such as tea and coffee bags. Thus the infusible substance disposed in the infusion containing chamber, while it can be any suitable such substance, would typically be tea or coffee or a herbal preparation, etc. , as is known in the art.

The shape of the expanded chamber can be selected as desired, but, as discussed above, it is preferably a more regular three-dimensional shape, such as a sphere or rugby-ball shape. The shape of the chamber in its flat configuration will depend upon its expanded shape, but is, as discussed above, preferably generally elliptical or circular in plan view.

The infusion package of the present invention can be made as desired. It could, for example, be formed by

folding separate webs of porous material and then sealing those webs to each other, with the infusible substance being disposed on one or between the webs prior to their being sealed together, and the sealed packages then cut appropriately from the webs to form the individual infusion package.

Thus, according to a further aspect of the present invention, there is provided a method of manufacturing infusion packages, the method comprising: providing a pair of continuous travelling webs for forming successive packages; folding one or both webs so as to form a pleat or pleats in the folded web or webs; dosing an infusible substance on one of the webs or between the webs; sealing the webs together to form a two-ply web having pockets containing the infusible substance in such a manner that each pocket has a pleat running across it, with the outer folded edge of the pleat lying inside and spaced apart from the outer periphery of the pocket; and cutting the pockets from the sealed webs so as to form infusion packages each having a chamber containing an infusible substance and having one or more pleats in it to permit expansion of the chamber.

In this aspect of the invention, the two webs could be two separate webs, or formed by a single web that is folded over, as is known in the art.

In a preferred embodiment of this aspect of the invention, the web or webs are folded substantially parallel to the direction of travel of the web or webs, but the pockets that are to form the infusion packages are. oriented with their central longitudinal axis at an angle to the direction of travel of the (sealed) webs.

(This angle can be selected as desired, but is preferably around or at 150 to the direction of travel of the (sealed) webs. ) This arrangement means that the

pockets in the sealed webs lie at an angle to the direction of travel of the sealed webs. For certain external pocket shapes, such as elliptical pockets, angling the pockets in this way can reduce the amount of waste web material and provide a greater surface area to dose the infusible substance onto. In this embodiment, the pleats in the finished packages will lie at an angle to the central longitudinal axis of the infusion-containing chamber.

A number of preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a plan view of a first embodiment of an infusion package in accordance with the present invention in its flat configuration; Figure 2 is a cross-sectional view along the line A-A of the infusion package in Figure 1; Figure 3 is a view of the infusion package of Figure 1 in its expanded form; Figure 4 is a plan view of the expanded infusion package of Figure 3; Figure 5 is a further view of the expanded infusion package of Figure 3; Figure 6 is a plan view of a second embodiment of an infusion package in accordance with the present invention in its flat configuration; Figure 7 is a schematic drawing illustrating a layout on a web of porous material of infusion packages as shown in Figure 6 during manufacture of those packages; Figure 8 is a plan view of a third embodiment of an infusion package in accordance with the present invention in its flat configuration; Figure 9 is a cross-sectional view along the line B-B of the infusion package in Figure 8; and Figure 10 is a view of the infusion package of

Figure 8 in its expanded form.

Figure 1 shows a first embodiment of an infusion package in accordance with the present invention in its flat, pre-expanded configuration. The infusion package comprises a chamber 1 which contains an infusible substance (which would typically be tea or coffee, as is known in the art). The chamber 1 has two panels of porous material 3,4 which are formed from two separate pieces of porous material sealed to each other around the peripheral margin 5 of the chamber.

The top panel 3 of the chamber includes two pleats 6,7 arranged symmetrically about the longitudinal central axis of the panel 3, thereby forming an effective box-pleat arrangement. The outer edges 8,9 of the pleats 6,7 extend longitudinally along the panel and are spaced inwardly from the outer peripheral margin of the chamber. Those edges 8,9 are formed by fold lines in the panel 3, and are not sealed to each other.

The inner edges 12,13 of the pleats also extend longitudinally along the panel and are formed by folds in the panel. The end edges 10,11 of the pleats are sealed together, as this is necessary to close the infusion containing chamber, and generally follow the outer profile of the sealed-together pieces of material forming the chamber until the start of the outer longitudinal edges 8,9 of the pleats. The pleats allow the panel 3 to expand.

The other panel 4 includes a corresponding pleat arrangement.

In this way the panels of the chamber 1 have pleats in them that allow the chamber 1 to expand in use.

It can be seen that the pleating arrangement of the panels of the chamber is such that the two pieces of porous material forming the chamber are joined to each other but not along their entire perimeter, rather the perimeter of the pieces is greater than the perimeter of their common seal. The additional material is neatly

accommodated in a central box pleat, with self-to-self sealing at the longitudinal ends of the pleats to ensure that the bag is fully sealed and the tea cannot escape.

The arrangement of the infusion package of this embodiment of the present invention is such that it will expand when immersed in hot liquid (i. e. upon infusion).

This is because when the package first contacts the hot infusing liquid, the hot liquid heats the air trapped within the chamber of the infusion package, thereby causing that air to expand. The pleats in the panels of the chamber are pushed out by the expanding air and allow the expansion of the package of the chamber to an expanded form. Thereafter, expansion is further assisted and maintained by the swelling of the infused material as it absorbs the infusing liquid.

Figures 3,4 and 5 illustrate the expanded form of the infusion package of Figure 1. It can be seen that the pleats 6 and 7 in the panel 3 have been opened out such that the panel forms a substantially hemisphericaj surface, save for the sealed ends of the pleats. Th panel 4 expands in a similar manner, and thus the

chamber (and in this embodiment therefore the overall infusion package) adopts a substantially spherical shape in its expanded form.

Because the pleats and edges of the pieces forming the chamber all come together at the apices of the chamber, the sealed margins tend to interlock at the apices in the expanded form of the package and this helps to prevent collapse of the package once it has expanded.

Although the arrangement and shape of the panels and pleats can be selected as desired, a particularly preferred embodiment of the present invention is an infusion package that will expand to produce a sphere.

The infusion package shown in Figures 1 and 2 is of the general configuration necessary to produce a sphere. In a particularly preferred arrangement of that infusion

package, to produce a sphere of volume 45 cm3 and therefore having a radius r of approximately 2. 2 cm, then a suitable arrangement for the outer periphery of the chamber in its flat configuration is an ellipse of approximately 3 r and width approximately 1.5 r at its widest point (both measurements excluding the sealed margins), with the central pleat (i. e. the material between the outer longitudinal edges 8,9 of the two pleats) having a width of approximately 1 r (i. e. each pleat effectively extending 0.5 r from the central longitudinal axis of the flat package).

Figure 6 shows a second preferred embodiment of an infusion package in accordance with the present invention in its flat, pre-expanded configuration. The package is similar to the package shown in Figure 1 (and like reference numerals are used for like features in Figures 1 and 6), except that the pleats 6a, 7a (and hence their outer longitudinal edges 8a, 9a, etc. ) in this embodiment lie at an angle of around 150 to the longitudinal central axis of the chamber of the package.

Figure 8 shows a third preferred embodiment of an infusion package in accordance with the present invention in its flat, pre-expanded configuration. The package is similar to the package shown in Figure 1 (and like reference numerals are used for like features in Figures 1 and 8), except that the package has a circular outer shape and only one of the panels is pleated (with two pleats 6b, 7b). Figure 9 shows a cross-section of the package along the line B-B in Figure 8. Figure 10 shows this infusion package in its expanded form.

It can be seen from the above that the present invention at least in its preferred embodiments provides an infusion package that can be arranged to expand in use to adopt a spherical or other three-dimensional form, and which can be made using only two pieces of porous material to construct the package. This is believed to have manufacturing advantages, since it

allows the infusion package to be made, for example, by modifying a more conventional infusion package manufacturing process that uses two separate continuous webs of porous material which are sealed together and from which the individual infusion packages are cut. In such a process for manufacturing an infusion package in accordance with the present invention, the continuous travelling web or webs should be appropriately folded to pleat it or them before the webs are sealed together.

An advantage of the arrangement of the present invention in this regard is that because the pleats in the panels do not extend to the periphery of the chamber of the infusion package, it is possible to seal the continuous webs together and cut the packages from the sealed webs whilst still leaving an uncut expansion pleat.

Figure 7 illustrates the layout of infusion packages 20 as shown in Figure 6 on a sealed two-ply 21 during manufacture of those packages (i. e. prior to the cutting of the packages from the web). It can be seen that the pleats 22 of the packages are parallel to the direction of travel 23 of the web 21, but the packages 20 themselves lie at an angle of around ISo to the direction of travel 23 of the web 21. Angling of the packages in this way reduces the amount of tissue waste and provides more surface area to dose the infusion onto, and results in the pleats lying at an angle to the infusion-containing chamber's central longitudinal axis in the finished packages.

Claims

1. An infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, wherein at least one of the panels of the chamber has at least one pleat in it, thereby permitting expansion of that panel, with the longitudinally extending outer edge of the pleat lying inside and spaced apart from the outer periphery of the chamber, and the arrangement being such that the chamber can swell to an expanded volume when immersed in a hot liquid.

2. An infusion package comprising an infusion containing chamber formed from one or two pieces of porous material, in which at least one of the panels of the chamber includes a pleat to allow for expansion of that panel, the arrangement being such that the chamber can swell to an expanded volume upon immersion in a hot liquid; wherein the pleated panel is arranged such that the facing surfaces of the panel extending from the inner edge of the pleat have different surface areas.

3. The infusion package of claim 1 or 2, wherein the chamber comprises two panels of porous material.

4. The infusion package of claim 1, 2 or 3, wherein each panel of the infusion containing chamber includes at least one pleat.

5. The infusion package of claim 1, 2 or 3, wherein only one panel of the chamber is pleated.

6. The infusion package of claim 1, 2,3, 4 or 5, wherein a panel of the chamber comprises two pleats with each pleat's longitudinally extending outer edge lying inside and spaced apart from the outer periphery of the

chamber.

7. The infusion package of claim 6, wherein the pleat arrangement is symmetrical about a longitudinal axis lying between the pleats.

8. The infusion package of claim 6 or 7, wherein the two pleats are arranged on opposing sides of a centre line of the panel.

9. The infusion package of any one of the preceding claims, wherein the inner and outer longitudinal edges of each pleat are substantially parallel to each other.

10. The infusion package of any one of the preceding claims, wherein the end edges of each pleat follow the profile of the outer periphery of the chamber.

11. The infusion package of claim 10, wherein each pleat runs along the outer edge of the chamber to the position of its outer longitudinal edge, the longitudinal edge of the pleat then extends across the chamber to the other end edge of the pleat, and that other end edge of the pleat runs along the outer edge of the chamber.

12. The infusion package of any one of the preceding claims, wherein the chamber establishes a three-dimensional shape upon immersion in a hot liquid that will not tend to collapse in use after it has initially expanded.

13.. An infusion package comprising an infusion-containing chamber formed from one or two pieces of porous material, wherein at least one of the panels of the chamber has a box pleat arranged in it whose outer edges lie inboard of the outer periphery of

the chamber, whereby that panel may expand, the arrangement being such that the chamber will swell to an expanded volume upon immersion in a hot liquid.

14. The infusion package of claim 13, wherein only one panel of the package includes a box pleat.

15. An infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, and in which the panels of the chamber are arranged to form three or more flaps extending from a central axis, with at least one of the flaps having a reduced width as compared to another of the flaps, the arrangement being such that the chamber can swell to an expanded volume upon immersion in a hot liquid.

16. The infusion package of claim 15, comprising two flaps having equal widths formed by the outer edges of the chamber and two reduced width flaps formed by pleats in one of the panels.

17. An infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, and in which the panels of the chamber are arranged such that the chamber effectively comprises six flaps extending around a central axis, the arrangement being such that the package can swell to an expanded volume upon immersion in a hot liquid.

18. The infusion package of any one of the preceding claims, wherein the chamber is elliptical in its flat configuration.

19. The infusion package of any one of the preceding claims, wherein the chamber is circular in its flat configuration.

20. The infusion package of any one of the preceding claims, wherein the outer longitudinal edges of the pleat or pleats are formed by means of a fold in the panels.

21. An infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, wherein one or more of the panels of the chamber includes a pleat, thereby allowing expansion of that panel, and wherein the outer edge of one or more of the pleats in the panels is formed by folding the panel to form that edge and the panel is not otherwise sealed along that folded edge.

22. An infusion package comprising a chamber formed from one or two pieces of porous material for containing an infusible substance, and wherein one or more of the panels of the chamber includes a pleat to allow expansion of that panel, the arrangement being such that the chamber can swell to a substantially spherical shape upon immersion in a hot liquid.

23. A method of manufacturing infusion packages, the method comprising: providing a pair of continuous travelling webs for forming successive packages; folding one or both webs so as to form a pleat or pleats in the folded web or webs; dosing an infusible substance on one of the webs or between the webs; sealing the webs together to form a two-ply web having pockets containing the infusible substance in such a manner that each pocket has a pleat running across it, with the outer folded edge of the pleat lying inside and spaced apart from the outer periphery of the pocket; and cutting the pockets from the sealed webs so as to

form infusion packages each having a chamber containing an infusible substance and having one or more pleats in it to permit expansion of the chamber.

24. An infusion package substantially as hereinbefore described with reference to any one of the accompanying drawings.

25. A method of manufacturing infusion packages substantially as hereinbefore described with reference to any one of the accompanying drawings.