GB2408252A

GB2408252A - Three-dimensional infusion packages

Info

Publication number: GB2408252A
Application number: GB0425762A
Authority: GB
Inventors: Duncan Ross Purvis; Richard Ford Freeman; Michelle Marie Eales; Gary Stacey; Paul Anthony Johnson
Original assignee: Tetley GB Ltd
Current assignee: Tetley GB Ltd
Priority date: 2003-11-24
Filing date: 2004-11-23
Publication date: 2005-05-25
Anticipated expiration: 2024-11-23
Also published as: GB2408252B; GB0425762D0; GB0327299D0; WO2005051797A1

Abstract

At least one panel of an infusion package is formed in such a way that it will adopt a three-dimensional shape in use. As shown, an infusion package 1 has two panels 2, 3, each of which has been formed to a hemispherical shape. The panels are sealed together around their peripheral margins 4 to form an infusion containing chamber that contains an infusible substance, such as tea or coffee. When the package 1 is immersed in hot liquid (e.g. by pouring water at 85{C to 100{C onto it) it will tend to re-adopt its formed shape and thus an expanded, three-dimensional, volume. There may be a support component within the package helping to form the shape.

Description

Infusion Packages 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.

Infusion packages that can adopt a three-dimensional shape during infusion are now becoming increasingly common. Such packages are believed to have consumer appeal. They can also improve infusion performance, as a more three-dimensional shape can allow a greater circulation and mixing of the infusing liquid around and into contact with the infusible material.

An example of a prior art three-dimensional infusion package is the known tetrahedral infusion package.

Other prior art designs for infusion packages that

will tend to adopt a more 3-dimensional shape on infusing have tended to focus on providing folds, or gussets, in the panels of the package that then allow the panels of the package to expand on infusion. Examples of such infusion packages are given in GB-A-2337738 and the Applicants own UK Patent No. 2369095.

Another design is shown in EP-A-0811562. That infusion package comprises 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. This arrangement again provides the facility for - 2 the package to expand when infused, by virtue of the folded pieces forming the package being able to open outwards from their folded configuration.

The Applicants believe that there remains scope for improvement in the design of three-dimensional infusion packages.

According to a first aspect of the invention, there is provided an infusion package comprising a chamber for containing an infusible substance, wherein at least one of the panels of the chamber has been formed into a three-dimensional shape such that the chamber can adopt an expanded volume upon immersion with a hot liquid.

In the present invention, one or more panels of the infusion package are formed into a three-dimensional shape. The Applicants have found that the panel or panels that have been formed in this way will tend to re-adopt their three-dimensional shape upon immersion with a hot liquid (i.e. upon infusion), thereby allowing the infusion package to adopt a threedimensional, expanded volume when, e.g. infusing. Furthermore, the Applicants have found that by "pre-shaping" or "pre-forming" a panel or panels of the infusion package to a three- dimensional shape in this way, the panel or panels will tend much more readily to re-adopt that three-dimensional shape upon infusion, as compared, e.g., to arrangements in which a panel must "unfold" to form the expanded volume. It is also believed that "forming" the panels to the desired shape allows a more selective and precise three-dimensional shape to be achieved, than when, e.g., relying on folding arrangements.

Furthermore, with the arrangement of the present invention, a smoother outer surface of the package when expanded can be achieved, as the presence of (large) creases or folds in the package can be reduced or avoided. This is believed to assist particularly the infusion package in spinning or tumbling in the infusing - 3 liquid when infused (as there is less drag), which is believed to further improve and enhance and accelerate the infusion process. The absence of larger folds and creases in the infusion package also helps to reduce or eliminate areas in the package that could trap the infusible material (that could again, e.g., hinder the infusing process).

The infusion containing chamber in the infusion package of the present invention should be formed from porous material, as is known in the art. It could be made from one or two or more pieces of porous material, as desired. The actual porous material used could be any suitable such material, such as commonly-used infusion package tissue comprising porous "paper" containing both cellulosic and thermoplastic fibres, or a plastic film (whether conventional or biodegradable).

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.

Most preferably both (or all) of the panels of the infusion-containing chamber have been formed to a three-dimensional shape. Preferably each shaped panel is formed to the same shape. The actual shape used can be selected as desired, but is preferably a particular, preferably predetermined, three-dimensional shape.

In a particularly preferred embodiment, the panel (and preferably each panel) is formed into a hemispherical shape, as that allows the infusion package to adopt a hemispherical or spherical (where both panels have been so formed) shape upon infusion. Indeed, the Applicants have found that an infusion package whose panels have been preformed to a hemispherical shape will tend to re-adopt a particularly good approximation to a sphere on immersion in an infusing liquid.

Other designs of shape might be geodesic shapes, such as geodesic domes, and shapes that are made up of a number of tessellating regions.

The way that the panels of the infusion package are formed to their threedimensional shape can be selected as desired. It should be appreciated in this regard that a requirement of the forming process is that the panel will tend to return to or re-adopt the shape that it has been formed to upon immersion with a hot (an infusing) liquid. However, the formed shape does not otherwise have to be set permanently, but could be only temporary or set to a partial degree, rather than completely set.

Indeed, it is anticipated and intended that with conventional infusion package materials at least, the panels of the package can (and will) be deformed from their formed shapes (and will not significantly resist such deformation) during, e.g., packing, distribution, and handling, but will, as set out above, tend to revert to their formed shape upon immersion with an infusing liquid.

As is known in the art, infusion packages are commonly made by taking a web or webs of porous material and sealing the web or webs together to form the infusion packages. Thus in a particularly preferred embodiment of the present invention, the infusion package is formed by forming the web or webs of porous material to be used to make the infusion package to have the desired three-dimensional shape before the web or webs are sealed together to form the individual packages.

Thus, according to a second aspect of the present invention, there is provided a method of manufacturing an infusion packages, comprising: providing a pair of continuous travelling webs of porous material for forming successive infusion packages; - 5 forming portions of one or both webs into a three-dimensional shape; dosing an infusible substance on one of the webs or between the webs; sealing the webs together to form a twoply web having pockets containing the infusible substance in such a manner that each pocket includes at least one formed portion of a web; and cutting the pockets from the sealed webs to form infusion packages each having a chamber containing an infusible substance and a panel or panels including at least one formed portion of a web.

According to a third aspect of the present invention, there is provided an apparatus for manufacturing infusion packages, comprising: means for providing a pair of continuous travailing webs of porous material for forming successive infusion packages; means for forming portions of one or both webs into a three-dimensional shape; means for dosing an infusible substance on one of the webs or between the webs; means for sealing the webs together to form a two-ply web having pockets containing the infusible substance in such a manner that each pocket includes at least one formed portion of a web; and means for cutting the pockets from the sealed webs to form infusion packages each having a chamber containing an infusible substance and a panel or panels including at least one formed portion of a web.

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

The way that portions of the webs are formed to have the threedimensional shape can be selected as desired.

For example, the shaped portions could be formed, e.g., - 6 as part of the material or "paper" making process for forming the web or webs in the first place, e.g. by laying the fibres to make up the web or webs onto an appropriately shaped former as the web or webs of tissue are themselves made.

However, in a particularly preferred embodiment, the shaped portions of the web or webs are formed by deforming or shaping portions of a substantially flat web of porous material to the desired threedimensional shape.

Thus, according to a fourth aspect of the present invention, there is provided a method of manufacturing infusion packages from a substantially flat web of porous material, comprising: deforming portions of the flat web of porous material to a three-dimensional shape; and forming infusion packages from the deformed web such that the infusion packages include a deformed portion of the web.

According to a fifth aspect of the present invention, there is provided an apparatus for manufacturing infusion packages, comprising: means for deforming portions of a flat web of porous material to a threedimensional shape; and means for forming infusion packages from the deformed web such that the infusion packages include a deformed portion of the web.

According to a sixth aspect of the present invention, there is provided an infusion package comprising a chamber for containing an infusible substance, wherein at least one of the panels of the chamber is formed from a substantially flat portion of porous material that has been deformed into a three-dimensional shape.

The web or webs of porous material could, e.g., be vacuum formed into the three-dimensional shape. In a - 7 particularly preferred embodiment they are so-formed mechanically, e.g. using an appropriately shaped forming tool that is, e.g., pressed into the web to deform it.

Most preferably this tool is in the form of co-rotating and cooperating forming rollers that have appropriate male and female portions and between which the web travels.

Most preferably the deforming of the web is accompanied by the application of one or more of heat, moisture and/or pressure to help to, e.g., at least partially "set" the web in the formed shape. In particular, the Applicants have recognised that in the case of web materials that include a thermoplastic component, such as is the case for materials commonly used to form infusion packages (that, as is known in the art, typically comprise porous paper tissue that includes heat-sealable fibres) , the application of heat can be used to exploit the presence of the thermoplastic, heat-sealing material to help form the infusion package tissue into the desired three-dimensional shape.

In particular, the Applicants believe that the application of heat firstly helps to soften the thermoplastic material, e.g., fibres, so that they can more plastically deform to the desired shape, with the consequent removal of the heat then allowing the deformed material to "set" in its new shape, thereby helping to "set" the "formed" shape of the web. Furthermore, as will be appreciated by those skilled in the art, when a flat piece of web is deformed to a three-dimensional, e.g., hemispherical form, there will inherently be some folding, pleating and gathering, etc. of the web material, particularly, e.g., at the base of the shape being formed. The application of heat has been found to encourage some localised heat sealing in these folded and gathered regions, which again tends to help "fix" and - 8 retain the formed shape once the, e.g., forming tool and pressure, is removed.

The conditions for heating the tissue as it is formed can be selected as desired, but should be so as to, e.g., suitably soften the heat-sealable fibres so that they can be deformed and then allow the fibres to set so as to retain the three-dimensional form of the web. It is also desirable that the heating does not significantly close the perforations in the tissue.

It is believed that as well as for the application of heat, similar effects, e.g., in helping to soften and then "set" any deformations in the tissue may be facilitated by applying moisture (preferably in combination with heat) to web materials that include, e.g., cellulosic fibres.

The Applicants believe that this may be the first time that anyone has recognised the possibility of forming infusion package tissue in these ways.

Thus, according to a seventh aspect of the present invention, there is provided a method of manufacturing infusion packages from a web of porous material that includes a thermoplastic component, comprising forming a portion or portions of the web into a three-dimensional shape whilst applying heat and/or moisture to the web prior to forming infusion packages using the web.

According to an eighth aspect of the present invention, there is provided an apparatus for manufacturing infusion packages from a web of porous material that includes a thermoplastic component, comprising means for forming a portion or portions of the web into a three-dimensional shape whilst applying heat and/or moisture to the web prior to forming infusion packages using the web.

According to a ninth aspect of the present invention, there is provided an infusion package comprising a chamber for containing an infusible - 9 substance, wherein at least one panel of the chamber has been formed to a three-dimensional shape using the application of heat and/or moisture.

These aspects and embodiments of the invention can include any one or more or all of the preferred and optional features of the invention described herein.

Thus, for example, the thermoplastic component of the porous material making up the infusion packages will typically be in the form of heatsealable fibres, e.g., of polypropylene.

It would also be possible to apply some form of setting or sizing agent, e.g. a suitable polymeric agent, to the web after it has been formed to again help to "set" and retain the formed shape.

As discussed above, when the three-dimensional shape is formed, the web of porous material will tend to become gathered up and folded, at least in some regions. While as discussed above, some such folding and gathering can be desirable, an excessive amount may be, e.g., cosmetically undesirable, and, furthermore, tend to close larger numbers of pores in the material. Where it is desired to reduce the extent of folding and gathering of the material when the three-dimensional shape is formed, then the (e.g. flat) web could, e.g., be appropriately relieved, e.g. by perforating it or providing pre-cuts in it, prior to it being formed to the desired three-dimensional shape, so as to reduce the amount of folding and overlapping of web material that occurs when the three- dimensional shape is formed.

It will be appreciated that as well as the processes discussed above that can help to set and retain the formed three-dimensional shape of the panels of the infusion package, the process of sealing the panels of the package together around their periphery will also help to retain the desired shape, as such sealing will constrain the ability of the panels to relax or deform to - 10 another shape. Such sealing can be effected in any suitable manner known in the art, such as by, for example, heat- sealing, ultrasonic welding or mechanical crimping.

All of these aspects and embodiments of the invention can, as will be appreciated by those skilled in the art, include any one or more or all of the preferred and optional features of the invention discussed herein.

Thus, for example, preferably both (or all) of the panels (and thus, e.g. both webs of porous material where appropriate) making up the infusion package are formed into a three-dimensional shape, and, most preferably, the deformed portions of the web or webs are formed into a hemispherical or substantially hemispherical shape.

In a particularly preferred embodiment, the infusion package of the present invention further includes a supporting component that provides a skeletal structure to help form the three-dimensional shape that the infusion package is to adopt when immersed in an infusing liquid. Thus, for example, in the case of a hemispherical or spherical infusion package, the package preferably further comprises a supporting ring that is attached to the panels of the package for helping to maintain its circular cross-section, i.e. to provide support around an equator of the package. This supporting structure is preferably of a more rigid material (and preferably is rigid (in normal use)) so as to help maintain the shape of the package even if its (more flexible) panels have been squashed or deformed.

It can also be used as a convenient component by which to hold the package.

The supporting component or components can be arranged as desired in the infusion package. It or they are preferably located at least partly within the infusion-containing chamber (and preferably wholly within it), and, preferably, are adhered to one or more panels of the infusion package. The supporting component is most preferably arranged to lie along the seal or seals that form the periphery of the chamber (particularly where it is in the form of a ring or hoop and the panels of the chamber are formed from one or two hemispherical pieces that are sealed together around their periphery) as that facilitates manufacture of the infusion package, and, e.g., can provide a more rigid surface against which to seal the porous material making up the package.

The supporting component can be made out of any suitable material that is, e.g., sufficiently rigid to provide support to, or a skeletal structure for, the walls of the infusion-containing chamber, such as an appropriate plastic material. In a preferred embodiment the supporting component or components are formed from the same polymer as is used to provide the heat-sealing fibres in the porous material forming the panels for the infusion package, i.e., typically, polypropylene. In another preferred embodiment, the supporting component or components are made of the same material as is used to form the panels of the package but, e.g., preferably in a thicker or folded arrangement so as to provide greater structural rigidity.

It is also envisaged that an infusion package could be provided with some form of skeletal component that will adopt a three-dimensional shape in use, for example in the manner of so-called tt shape memory" material. This could allow, e.g., a "conventional" flat infusion package to be forced to adopt a three-dimensional shape by including in the package a skeletal component that will itself deform (and thereby deform the infusion package) on immersion in an infusing liquid.

It is again believed that the idea of an infusion package containing some form of more rigid supporting or skeletal component may be novel and inventive in its own right. Thus, according to a tenth aspect of the present invention, there is provided an infusion package comprising a chamber for containing an infusible substance, and further comprising one or more supporting components that help to form the chamber into a particular shape.

According to an eleventh aspect of the present invention, there is provided a method of manufacturing an infusion package, comprising: including in the infusion package one or more supporting components that can help to form an infusing-containing chamber of the package into a particular shape.

According to a twelfth aspect of the present invention, there is provided an apparatus for manufacturing an infusion package, comprising: means for including in the infusion package one or more supporting components that can help to form an infusion-containing chamber of the package into a particular shape.

According to a thirteenth aspect of the present invention, there is provided an infusion package, comprising: one or more supporting components that help to form an infusion-containing chamber of the package into a particular shape.

These aspects and embodiments of the invention can again include any one or more or all of the preferred and optional features of the invention discussed herein.

Thus, for example, the supporting component or components preferably help to support the chamber in a particular three-dimensional shape, and could, e.g., be in the form of a hoop or ring. They could also comprise a component or components that will tend to deform to a particular threedimensional shape from another form (e.g. a substantially flat configuration) upon immersion in an infusing liquid. - 13

Thus, according to a fourteenth aspect of the present invention, there is provided an infusion package comprising: a component or components that will tend to deform to a particular three-dimensional shape from another form upon immersion with a hot liquid.

It will be appreciated from the above that the present invention provides an infusion package whose panel surface area is greater than the largest corresponding cross-sectional area of the corresponding panel (in contrast to a conventional flat teabag where each panel's surface area will be the same as its largest cross-sectional area), by forming the panel or panels to have a three-dimensional shape. This should be contrasted with existing infusion package designs that provide such "excess" panel surface area by the use of folds or gussets that can open out in use.

Thus, according to a fifteenth aspect of the present invention, there is provided an infusion package comprising a chamber for containing an infusible substance, wherein the surface area of at least one of the panels of the package is greater than the largest cross-sectional area of that panel when the infusion package is immersed with a hot liquid, and that panel is substantially without any expansion folds or creases in it.

Again, this aspect of the present invention can include any one or more or all of the preferred and optional features of the invention discussed herein.

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., dualchambered, infusion packages if desired, to provide such a package with one or more three-dimensionally shaped chambers upon infusion.

The present invention is applicable to infusion packages generally, although 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 infusion packages of the present invention can be made as desired, and are preferably made as discussed above. Thus, they are preferably made by forming a web or, e.g., two separate webs, of porous material into the desired shapes, and then sealing the web or 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 sealed web or webs to form the individual infusion packages. As is known in the art, the webs used to form the packages could be two separate webs, or formed by a single web that is folded over.

In a preferred embodiment, the infusible material is dosed during the manufacturing process into a portion of a web that has been deformed, as that can help to retain the infusible substance away from the region or regions of the web that will subsequently be (heat) sealed when the infusion package is formed.

In a preferred embodiment where both panels of the infusion containing chamber are formed into a three-dimensional shape (e.g. hemispheres), the second panel is preferably laid inside the first panel (after the infusible material has been dosed into the first panel) with the panels (i.e. what will become the panels of the package) then being sealed together. This is believed to be a particularly convenient way to manufacture, e.g., a spherical infusion package. Once formed, the package can then, e.g., be shaken to invert the second panel to provide its intended, e.g. convex hemispherical, shape.

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: Figures 1 and 2 show a first embodiment of an infusion package in accordance with the present invention; Figures 3 and 4 show schematically part of a first method of manufacturing the infusion package of Figures 1 and 2; Figures 5 and 6 show schematically a second method of manufacturing the infusion package of Figures 1 and 2; Figures 7 and 8 show a second embodiment of an infusion package in accordance with the present invention; Figure 9 shows schematically a supporting ring used in the infusion package of Figures 7 and 8; Figures 10 and 11 show schematically a method of manufacturing the infusion package of Figures 7 and 8; and Figures 12 and 13 show schematically another method of manufacturing the infusion package of Figures 7 and 8.

Figures 1 and 2 show a first embodiment of an infusion package in accordance with the present invention. The infusion package 1 has two panels 2, 3, each of which has been formed to a hemispherical shape.

The panels are then sealed together around their peripheral margins 4 to form an infusion containing chamber that contains an infusible substance, such as tea or coffee.

As can be seen from Figures 1 and 2, the infusion package essentially comprises two hemispheres, which are joined with an external, equatorial seal or frill where the panels of the package are sealed together. When the - 16 package 1 is immersed in hot liquid (e.g. by pouring water at 85 C to 100 C onto it) it will tend to re-adopt its formed shape and thus an expanded, three-dimensional, volume. This is because, inter alla, the heat of the water causes the air trapped inside the package to suddenly expand, thereby expanding the package to its three-dimensional form. It will be appreciated in this regard that the panels of the infusion package are not rigidly set in their formed, hemispherical shapes, but can be deformed therefrom. However, when, e.g., the air inside the package expands, the package will tend to re-adopt the hemispherical shape that it has previously been formed into.

As is known in the art, conventional infusion package material consists of cellulosic fibres and polypropylene fibres (which polypropylene fibres are usually deposited onto the paper on one side only to confer the ability for two sheets of infusion package tissue to be welded together with the application of heat). The Applicants have found that the presence of the polypropylene also enables the infusion material itself to be formed into three-dimensional shapes, such as a hemisphere or near- hemisphere, using the application of heat and shaped former. Upon cooling, the shape into which the tissue has been formed tends to be retained, even after subsequent cold deformation.

In particular, the Applicants have found that heat can be used to softenthe polypropylene heat-sealing fibres included in the infusion package tissue, such that the tissue can then be deformed into a desired threedimensional shape, with the polypropylene fibres then being allowed to set and thereby retain the three-dimensional form. Furthermore, as can be seen from, e.g., Figure 1, the forming of the three-dimensional shape will tend to cause some gathering and overlapping of the infusion package material, - 17 particularly around the base of the shape being formed.

The application of heat can cause some localised heat sealing of these overlapping folds in the material, which sealed folds will then also help to retain and encourage the three-dimensional shape of the package.

Figures 3 and 4 show schematically part of a method of manufacturing the infusion package shown in Figures 1 and 2.

Figure 3 shows schematically the forming process. A web of porous material 60 for making one panel of the infusion package is placed between two forming tools 61, 62, comprising a shaped former 61 that is cylindrical with a hemispherical or near-hemispherical tip constructed of aluminium, and a corresponding, receiving, aluminium cylinder 62. The polypropylene-loaded side of the porous material 60 is arranged to face towards the hemispherical former 61. The hemispherical former 61 is heated to 60 C, and the receiving cylinder 62 is heated to 9 O C.

To deform the web 60 to the desired hemispherical shape, the hemispherical forming tool 61 is lowered into the receiving cylinder 62 at the rate of approximately mm per second. In this embodiment, it penetrates mm into the cylinder 62. After being held in position for 3 seconds the shaped forming tool 61 is withdrawn again at a rate of approximately 20 mm per second.

The result of this is that the web of porous material 60 is formed into a shape that mimics that of the leading edge of the forming tool 61 (i.e. a hemisphere or similar shape), with its concave face being the polypropylene impregnated (i.e. adhesive) surface.

There also remains a 'frill' of unchanged, flat porous material 62. (The inner portion of the frill may have been formed by heating (depending on the shape of the tools 60, 61), but there will be a surrounding portion of untreated frill.) Figure 4 shows schematically the two stages of the web of porous material, i.e. in its flat, unformed configuration, and then after it has been formed to the hemispherical shape. Figure 4 also shows the use of pre-moulding V-shaped cut-outs 65 in the flat web 60 to reduce the concentration of gathered, pleated and overlapping material in the formed hemisphere.

To produce the infusion package shown in Figures 1 and 2, the above process can be used to form two portions of web that will make up the panels of the infusion package. The infusible substance such as tea can then be dosed into one of the hemispherical portions, with the other hemispherical portion then being located, e.g., over the first (with its concave side downwards), and then sealed thereto around the periphery of the hemispherical portions. The sealed infusion packages can then be cut from the web to remove, e.g., any excess frill of porous material.

Figures 5 and 6 show schematically a second method of manufacturing the infusion package of Figures 1 and 2.

Figure 5 shows schematically the forming operation of this embodiment. A web of porous material 10 is passed between two co-rotating and cooperating shaped and heated rollers 11, 12, that, as shown in Figure 5, form the web such that it then has a series of hemispherical protrusions 13 on it.

Figure 6 shows the manufacturing process in more detail.

As shown in Figure 6, the infusion packages are formed from two separate webs of porous material 20, 21.

Each web is first formed into the appropriate hemispherical shape by means of cooperating heated rollers 22, 23. The infusible substance (which in the present example is tea) is then dosed into the hemispherical portions of one of the webs 20 by means of a tea dosing roller 24. - 19

As shown in Figure 6, the dosed tea is retained against the bottom surface of the hemispherical portions of the webs by means of a vacuum 25. An advantage of dosing the infusible substance into the formed hemispherical portions of the web is that the infusible substance will tend to collect in the bottom of the hemispherical portions and therefore can more easily be retained away from and clear of the areas of the webs that are to be sealed to form the individual infusion packages.

The cooperating rollers 23 then act to seal the webs 20, 21 together around the periphery of the hemispherical portions that have been formed so as to form closed chambers 26 containing the infusible substance. The enclosed chambers are then cut from the webs by means of cooperating and co-rotating cutting rollers 27, and finally the individual infusion packages 28 are removed from the web by means of a hammer 29. (Such use of co-rotating rollers for, e.g., sealing and cutting infusion packages from travailing webs is described, for example, in the Applicant's European Patent No. 0548057.) Figures 7 and 8 show a second preferred embodiment of an infusion package in accordance with the present invention. This infusion package 30 is again formed from panels of porous material 31, 32 that have been formed into a hemispherical shape. However, the infusion package further comprises a rigid plastic supporting ring or hoop 33 to which the panels have been sealed. This supporting ring provides an equatorial circumferential support for the infusion package to help it to form and maintain its three-dimensional shape and also provides a convenient, more rigid, surface against which the porous material forming the panels of the infusion package can be sealed. It accordingly eliminates, for example, the sealed frill or flange that is present in the infusion package shown in Figures 1 and 2. -

The presence of the more rigid support ring 33 helps to retain the shape of the infusion package in use, even if, for example, it may be squashed down when packaged or transported, etc. It also provides a convenient component by which to hold the infusion package. It can in effect act as a skeletal structure that helps to form the desired three-dimensional shape of the expanded package.

Figure 9 shows schematically the supporting ring 33.

It is made from polypropylene, although other materials such as paper, cardboard, ceramic, wood and other plastics could be used, if desired. The ring 33 is cylindrical in form, with a cylindrical internal face and an external face which is also cylindrical but with two chamfers 80, 81. These chamfered surfaces are not essential, but make it easier to seal (weld) the infusion package panels to the ring 33 (as discussed further below). It would also be possible to use a supporting ring 33 that has a different external profile, such as a spherical external profile.

To manufacture the infusion package shown in Figures 7 and 8, two hemispheres of porous material are first formed, for example, in the manner discussed above. One hemisphere 70 (of formed material) is then welded to the supporting ring 33 (at welds 74) using the application of heat, as shown in Figure 10, and cut out. After cutting out, the excess frill of unformed material 71 is then folded down, held against the supporting ring 33, and then welded thereto, for example by rolling the folded frill and ring 33 against a metal hot plate (e.g. of aluminium alloy) at, e.g., 180 C.

Tea (or another infusible substance) can then be dosed into the formed hemisphere 70.

Then as shown in Figure 11, the second hemisphere 72 can similarly be welded to the ring 33 (at welds 74) and its frill 73 folded down and again welded to the ring (or the frill of the other hemisphere) to provide a smoother outer surface. As can be seen from Figures 10 and 11, the hemispheres 70, 72 are welded to the chamfered surfaces of the supporting ring 33.

The frill 73 of the second hemispherical portion 72 will, as can be seen from Figure 11, be folded down and welded to either the surface of the supporting ring 33, or the already welded frill 71 of the first hemispherical panel 70.

The resulting infusion package is spherical in shape, and contains a polypropylene supporting ring 33 which is welded to both hemispheres 70, 72, and which therefore bonds the hemispheres together.

Figures 12 and 13 show schematically another method of manufacturing the infusion package shown in Figures 7 and 8. Again, as shown in Figure 12, the webs 40, 41 of porous material to form the infusion package are first formed to have hemispherical portions 42 into one of which an infusible substance 43 such as tea is dosed.

This can be done in the same way as described above in relation to, for example, Figure 6. In this embodiment, there is also provided between the webs 40, 41 of porous material a skeletal structure or web 44 of a more rigid polymeric material that will form the supporting rings 33 in the finished infusion packages. As shown in Figure 12, the components are brought together (stage 1 of Figure 12), assembled (stage 2), and then heat sealing is applied (stage 3) which seals the webs 40, 41 to the skeletal polymeric structure 44.

Then, as shown in Figure 13, the individual infusion packages can be cut from the web (stage 4) and, if desired, hot cutting or another process could be used to blunt or smooth any protruding more rigid polymeric material 50 (stage 5). For example, the finished packages could be rotated against a hotplate to melt and smooth any protruding polymeric material.

Although it is preferred in the present embodiments to use the application of heat when forming the panels of the infusion package, other techniques would be possible.

For example, moisture could also or instead be applied to the webs, or the webs could be vacuum-formed to provide the appropriate shapes for the panels. It would also be possible to form the infusion packages from material other than "conventional" infusion package tissue, such as, for example, an appropriate porous plastic film or sheet (which could, e.g., be supplied in a porous form or made porous as part of the infusion package making process).

It can be seen from the above that the present invention in its preferred embodiments at least provides an infusion package that will, upon immersion in an infusing liquid, adopt a desired three-dimensional shape that can lead to, for example, improved infusion performance. In arrangements in which the infusion package has hemispherical panels, it can form a substantially spherical shape on infusion that has a relatively smooth surface and that therefore allows the package to spin and tumble end-over-end in the infusing liquid. This motion in the water is believed to be encouraged by the relatively smooth nature of the outer surface of the infusion package. It is also believed that this motion in the water substantially helps to increase the infusion rate, as it allows the water to move in and around and into contact with the infusible material more easily. - 23

Claims

1. An infusion package comprising a chamber for containing an infusible substance, wherein at least one of the panels of the chamber has been formed into a three-dimensional shape such that the chamber can adopt an expanded volume upon immersion with a hot liquid.

2. The infusion package of claim 1, wherein all of the panels of the infusion-containing chamber have been formed to a three-dimensional shape.

3. The infusion package of claim 1 or 2, wherein the or each formed panel of the chamber has been formed into a hemispherical shape.

4. An infusion package as claimed in claim 1, 2 or 3, wherein the formed panel of the chamber is formed from a substantially flat portion of porous material that has been deformed into a three-dimensional shape.

5. An infusion package comprising a chamber for containing an infusible substance, wherein at least one of the panels of the chamber is formed from a substantially flat portion of porous material that has been deformed into a three-dimensional shape.

6. An infusion package as claimed in any one of the preceding claims, wherein the formed panel of the chamber has been formed to a threedimensional shape using the application of heat and/or moisture.

7. An infusion package comprising a chamber for containing an infusible substance, wherein at least one panel of the chamber has been formed to a - 24 three-dimensional shape using the application of heat and/or moisture.

8. An infusion package as claimed in any one of the preceding claims, further comprising a supporting component that helps to form the chamber into a particular shape.

9. An infusion package comprising a chamber for containing an infusible substance, and further comprising one or more supporting components that help to form the chamber into a particular shape.

10. An infusion package as claimed in claim 8 or 9 wherein the supporting component comprises a ring.

11. An infusion package as claimed in claim 8, 9 or 10, wherein the supporting component or components is made of a material that is used in or to form the panels of the package.

12. An infusion package comprising: a component or components that will tend to deform to a particular three-dimensional shape from another form upon immersion with a hot liquid.

13. An infusion package as claimed in any one of claims 1 to 8 or claim 10 or 11 when dependent upon claim 8, wherein the surface area of the formed panel of the package is greater than the largest cross- sectional area of that panel when the infusion package is immersed with a hot liquid, and that panel is substantially without any expansion folds or creases in it.

14. An infusion package comprising a chamber for containing an infusible substance, wherein the surface - 25 area of at least one of the panels of the package is greater than the largest cross-sectional area of that panel when the infusion package is immersed with a hot liquid, and that panel is substantially without any expansion folds or creases in it.

15. A method of manufacturing an infusion packages, comprising: providing a pair of continuous travailing webs of porous material for forming successive infusion packages; forming portions of one or both webs into a three-dimensional shape; 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 includes at least one formed portion of a web; and cutting the pockets from the sealed webs to form infusion packages each having a chamber containing an infusible substance and a panel or panels including at least one formed portion of a web.

16. The method of claim 15, comprising forming the shaped portions of the web or webs by deforming or shaping portions of a substantially flat web of porous material to the desired three-dimensional shape.

17. A method of manufacturing infusion packages from a substantially flat web of porous material, comprising: deforming portions of the flat web of porous material to a three-dimensional shape; and forming infusion packages from the deformed web such that the infusion packages include a deformed portion of the web. - 26

18. The method of claim 15, 16 or 17, comprising forming the shaped portions of the web or webs mechanically.

19. The method of claim 15, 16, 17 or 18, wherein the forming of the web is accompanied by the application of one or more of heat, moisture and/or pressure.

20. A method of manufacturing infusion packages from a web of porous material that includes a thermoplastic component, comprising forming a portion or portions of the web into a three-dimensional shape whilst applying heat and/or moisture to the web prior to forming infusion packages using the web.

21. The method of any one of claims 15 to 20, comprising: including in the infusion packages one or more supporting components that can help to form the infusing-containing chambers of the packages into a particular shape.

22. A method of manufacturing an infusion package, comprising: including in the infusion package one or more supporting components that can help to form an infusing-containing chamber of the package into a particular shape.

23. The method of any one of claims 15 to 21, wherein the webs used to form the packages are two separate webs, or formed by a single web that is folded over.

24. The method of any one of claims 15 to 21, comprising dosing the infusible substance into portions of a web that have been formed into a three-dimensional shape.

25. An apparatus an apparatus for manufacturing infusion packages, comprising: means for providing a pair of continuous travailing webs of porous material for forming successive infusion packages; means for forming portions of one or both webs into a three-dimensional shape; means for dosing an infusible substance on one of the webs or between the webs; means for sealing the webs together to form a two-ply web having pockets containing the infusible substance in such a manner that each pocket includes at least one formed portion of a web; and means for cutting the pockets from the sealed webs to form infusion packages each having a chamber containing an infusible substance and a panel or panels including at least one formed portion of a web.

26. An apparatus for manufacturing infusion packages, comprising: means for deforming portions of a flat web of porous material to a threedimensional shape; and means for forming infusion packages from the deformed web such that the infusion packages include a deformed portion of the web.

27. The apparatus of claim 25 or 26, comprising means for forming a portion or portions of the web into a three-dimensional shape whilst applying heat and/or moisture to the web prior to forming infusion packages using the web.

28. An apparatus for manufacturing infusion packages from a web of porous material that includes a thermoplastic component, comprising means for forming a portion or portions of the web into a three-dimensional shape whilst applying heat and/or moisture to the web prior to forming infusion packages using the web.

29. The apparatus of any one of claims 25 to 28, comprising: means for including in the infusion packages one or more supporting components that can help to form the infusing-containing chambers of the packages into a particular shape.

30. An apparatus for manufacturing an infusion package, comprlslng: means for including in the infusion package one or more supporting components that can help to form an infusing-containing chamber of the package into a particular shape.

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

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

33. An apparatus for manufacturing infusion packages substantially as hereinbefore described with reference to any one of the accompanying drawings.