GB2519319A - Coffee capsule - Google Patents

Abstract

A capsule 1 having a generally frusto-conical form with an upper surface and lower surface, an annular flange 4 is provided at the lower surface. The annular flange is provided with a sealing means on a surface facing towards the upper surface, wherein the sealing means comprises first 5 and second walls 6 spaced from one another and adapted to engage with an element of a coffee machine capsule cage. There is also an additional element 7 provided between the first and second walls, disposed at an angle to the first and second walls. The first and second walls can be concentric with the additional element creating a zig-zag 7 between the concentric walls.

Description

coffee Capsule The invention relates to a capsule for making espresso coffee using an espresso machine.

Powered espresso machines arc well known. The conventional espresso machine comprises a water chamber, a heating element adapted to heat the water to around 95- 98 C, Mich is then pumped under high pressure of IS to 19 bar to a filter holder or portafilter. Lower pressure systems also exist The filter holder typically comprises a handle portion and a holder portion provided with two or three lugs that are adapted U) engage in the installed position with the machine brewbead to where the water is pumped. The holder portion is adapted to receive a filter, which is usually a metal bowl with a number of perforations through its bottom. In use, the filter is filled with finely ground coffee and the water is forced through the coffee at the high pressure generated by the pump to produce the espresso cofkc which is collected in a cup placcd under the filter holder.

The classic coffee machine suffers from two potential drawbacks. The first drawback is that ground coffee starts to lose its freshness and flavour after a few days and so for the optimum espresso, the user will also need to have a coffee grinder. The other drawback is that the used espresso coffee has to be removed from the ifiter, which can leadtomessasthegrindsarefine.

This lead to the development of LiNE coffee pods, which can be used in many espresso machines. Coffee pods are generally individually wrapped to maintain freshness and consist of a small pod made of a perforated filter paper which contains the coffee. The pod is placed in the filter holder and then disposed of after use.

coffee pods are convenient but have to fit the ifiter holder and be placed correctly otherwise water can leak around the edge.

This in turn lead to the development of capsule machines. llie coffee capsules for these machines are completely sealed. The capsule machines do not use the conventional filter holder. A capsule machine typically has a two part mechanism.

The first part receives the capsule and is provided with an extraction surface upon which the capsule rests. The second part is provided with a locking lever which is used to make the first and second parts iniegral. In use, the second part cuts the upper surface of the capsule to allow water to enter the capsule and percolate down through the capsule. where it exits through the lower surface of the capsule at multiple locations determined by-the aeometry of the extraction surface. An example of such a machine is disclosed in liP 0870457 or WOWOS10046SJ. Capsules in the known capsule coffee machines are, in use, inserted into a capsule cage of the machine which holds the capsule in position so that it may he cut by a cutting member.

Capsule machines have proved to he commercially very successfuL as they arc very convenient to use and produce a consistent product. However, each manufacturers coffee machines and capsules are designed to work with the manul cturers own brand. The most popular brand of capsule is Nespresso UI), which uses a sealed capsule. in use, the capsule is dampen into position in the machine with a capsule cage part holding the capsule so that it can he cut by three prongs to enable water under pressure to enter the coffee capsule. The main alternative to this type of capsule is perforated with 6 to 9 holes to enable the water to enter the capsule. The perforations have onc significant design drawback in that air can enter the capsule.

Consequently, the capsules are packaged in small quantities in nitrogen iii ed bags to enable the shelf life of the coffee to match that of a sealed capsule. Ihis results in significantly increased transport and packaging costs.

A particular problem with capsule systems is ensuring a right fit between the capsuic cage and the capsule rim in the extraction position, Early sohitions relied on simple mechantcal pressure hut more recent capsules have used a rubber elastic seal such as silicone around the rim due to changes in capsule cage design. in use the capsule cage is applied to the seal to ensure that there is no loss of pressure. This seal has been effective but adds considerably to the production costs of the capsule.

It has been further proposed to use a series of de'formabie concentric rings formed on the rim, which in use are engaged by the capsule cage and deflected to ensure a pressure tight seal. However, the concentric rings need to be closely spaced and if a plastic capsule is used, then in production the capsue otten stick.s to mould.

Removing the capsule then resuks in wear to the tool.

The present invention seeks to provide a coffee capsule with an improved seal.

According to the invention there is provided a capsule for use in a coffee machine having a generally frusto-conical form with an upper surface and a lower surface, an annular flange being provided at the lower suricc, which annular flange is provided with sealing means on the surface facing towards the upper surfitce, wherein the sealing means comprises first and second walls spaced from one another and adapted to engage with an element of a coffbe machine capsule cage, wherein a lbrther element is provided between the first and second walls, which further element generally comprises an element disposed at an angle to the first and second walls.

Preferably, the first wall is substantially annular and the second wall comprises part of or is integral with the frustoconical form. Preferably the wails thereby form a gully.

Preferably, the further element comprises a zigzag wall. Preferably, the angle between adjacent walls of the zig zag is between 600. and 1200 Preibrably the zigzag wall is upstanding. Alternatively, the walls could be cut out from the rim. Preferably, the capsule is made of polypropylene or a co-niouldcd plastic.

It has surprisingly been found that the provision of the intermediate wall results in a more reliable seal and that the capsule is easier to remove from the mould tool during production. The mould tool therefore has a longer life than with the known capsule seal designs.

Exemplary embodiments of the invention will now be described with reference to the drawings, in which: Fig. 1 shows a perspective view of the capsule Fig. 2 shows a top view of the capsule Fig. 3 shows an alternative capsule Figure 1 shows a perspective side section of capsule 1 having a generally frustoconical form and Figure 2 shows a top view of the same capsule. The upper end of the cone frustrum has a smal let diameter than the lower end. The surface of the upper end of the cone is provided with a zone of weakness 2 in the form of an annular groove on the outer surface of the capsule. In use, cutting members of the capsule machine will sit just above the surface of The groove but do not pierce the capsule so that in use the water pressure bursts the weakened section and creates the path for the water to ingress the top of the capsule and into the coffee. in a manual machine that does not have cutting members, the water will simply tear or break the capsule at the zone of weakness.

If the capsule is made of a food grade plastic such as polypropylene, this arrangement substantially reduces air movement between the inside and the outside of the capsule thereby greatly extending the time that the coffee in the capsule retains its aromas. In use, the capsule should be flushed with nitrogen prior to being filled to prevent oxygen degrading the quality of the coffee. This in turn enables the producer to achieve an acceptable shelf life for the coflèe without the use of' a nitrogen filled pillow bag. In a particularly preferred embodiment the capsule wall is generally about 0.8mm thick but the wall around the zone of weakness is only about 0.5mm thick. The interior surface of the upper end has a small stepped profile in the region of the zone of weakness, so that the wall is thicker near the edge of the groove. This encourages the wall to tear near the centre of the groove or undercut rather than at the edge.

The lower end of the capsule is provided with a foil seal 3, which foil seal, in use,, is pressed against a filter element typically comprising a plurality of the upstanding truncated pyramids and adapted to assist in the tearing of the foil in use so that the coffee extracted from the coffee granules can percolate out of the capsule through holes in the filter.

The interior of the capsule is provided with several strengthening ribs to reduce the likelihood of the capsule collapsing under the pressures to which it is subjected in use.

The pressure on the inside of the capsule is typically in the range of 3 to 8 bar depending on the coffee machine and the packing density of the coffee in the capsule.

This pressure is sufficient to cause the foil to tear against a filter plate in tie coffee machine.

The capsule is provided with a flange 4 at its ower eric!, which flange 4 is adapted to co-operated with a retaining mechanism of a cotibe machine in use so that the capsule.

can be held in the correct position when in use in the coffee machine. The flange is prosdded with a first upstanding wall S spaced from the exterior of the ustueoneal svali 6 of the capsule. in use the capsuk cage walls hear against at least one c-f these upstanding walls. A.liirther zigzag wall 7 is Provided between the first and second wails. ihe angle between the adjacent wall elennentsis between 600 and 120°, most typically around 90" The zigzag wail 7 is deformahie by the action of the capsule cage and provides for an improved seal compared to the concentric eirees of the prior art as the capsule cage mouth is typically casteliated and the zie2ag pattern engages with the eastellanons in a sealing fashion. The zigzag wall need not he substantially vertical or upstanding but could a]so he at an angle to the flange surface. It would also he possible fin the first 5 and second 6 walk and the zigzag wall 7 to be eat from the surf cc of a thicker flange. The upstanding walls are generally aroimd 05-0,6mm high but could potentially be in he range 0,2 1.2 rum Figure 3 shows an alternative capsule to that shown in Figures i and 2. [he capsule is provided with a flange 4 at its lower end, which flange 4 is adapted to co-operated with a retaining mechanism of a coffee machine in use Sc) that the eapsu]c can he' held in the correct posiuon when in use in the coffee machine. The flange is provided with a Iirst upstanding wail 5 spaced from the exterior of the fiusto-conical wall 6 of the capsule. In use the capsule cage wails hear against at least one of these upstanding walls. Radial webs 8 are provided between the first wail 5 and the exterior of the frusto-conical wail 6. The radial webs are spaced around 1mm apart.

The capsule does not have a regular conical outer diameter over its entire length. The outer diameter of the upper part of the capsule is initially vertical and increases at a first rate until it reaches shoulder 8 when the outer diameter increases by a small amount to provide a shoulder to the rim of the capsule. The radial webs are generally.

around 0.5-0.6mm high but could potentially-he in the range 0,2 1.2 mm.

FL wtu.1d be po.r5ihie to ptuvide the wall 7 or webN: S with a: a anifered edge., a.round edge or ItwouM also be possibtr to have. the outer diameter (ish cteae: [ a ctoM rate granter thrrrtbe hn4 ratepnttl the run aithe eapsuk.

In uae the: eapsule.. can Ic inserted in a eo}wennonnl naelnne and the arrangenw.nt of the annular zone at weakness enaliles tin: Upper sarftwe; ol the; eapsitk a. be. torn by water pressure. from the espresso machine; Witbeut the need fbi.a c.un:in.g:.device.. The *apcuk N tbci due ufl hfe fur u'c w con entional e'pn\o nucianc> a' a' cap.ute U IL WWS the pressure of force We thu. agaiti the m.te}: plate at the as esse mwrhme. to. enabll.e the extracted cotke to petolate outeftIte eopsuk Atth.ong.h the capsule. has been.spe.dflcally described as bei.n used to make espresso ec.lfe& it. VV()u (3: be osathic to make other:hëveraoes such 25 R or chocOlate:,

Claims (9)

1. Claims 1. A capsule fin use in a coffee machine having a generally frusto-*conicai thrrn with an upper surface and a lower surfiice, an annular flange being provided at the lower surface, which annular flange is provided with sealing means on the surface facing towdrds the upper surface, wherein the sealing means eomprses first and second walls spaced from one another and adapted to engage with an clement of a coffee machthe capsule cage, wherein a further element is prooded between the first and second walls, which further element generally comprises an element disposed at an angle to the first and second walls.
2. 2. A capsule according to Claim 1, wherein the first. and second wails and the second wail comprises part of or is integral with the frustoconical form.
3. 3. A capsule according to Claim I or Claim 2, wherein the further cLement comprises a zigzac wall.
4. 4. A capsule according to Claim 3, wherein the angle between adjacent wails of the zig zag is between 600, and 120°.
5. 5. A capsule according to Claim 3 or Claim 1, wherein the zigzag wail is upstanding.
6. 6. A capsule according to any one of Claims I to 5, wherein the walls are cut out Irom the rim.
7. 7. A capsule according to am' one of Claims I to 6, wherein the capsule is made of polypropylene.
8. 8. A capsule according to any one of Claims I to 7, wherein the thrthcr clenmts comprises a plurality of radial webs spaced from one another.
9. 9. A capsule substantially as described herein with reference to and as illustrated in the accompanying drawing.