KR20220017923A - drink capsules - Google Patents

Abstract

Capsules for use in coffee machines having a brew chamber are formed of a soft metal such as aluminum. The capsule has a generally frustoconical shape with an upper surface and a lower surface, and an annular flange is provided on the lower surface. An annular seal having first and second layers is provided on the annular flange, the first layer comprising long, well-bonded fibers of cellulosic material.

Description

drink capsules

The present invention relates in particular to beverage capsules for espresso machines, for the production of espresso under high pressure.

Electric espresso machines are well known. A conventional espresso machine comprises a water chamber and a heating element configured to heat the water to about 95 to 98° C., after which the water is pumped into a filter holder or portafilter under a high pressure of 15 to 19 bar. Low pressure systems also exist. A filter holder typically includes a handle portion and a holder portion, provided with two or three lugs configured to engage in an installed position with a machine brewhead into which water is pumped. A holder portion, which is a conventional metal bowl with a number of perforations in the bottom, is configured to receive the filter. In use, the filter is filled with fine ground coffee, and water is pressurized through the coffee at high pressure generated by a pump to produce espresso coffee that is collected in a cup placed below the filter holder.

Traditional coffee machines have two potential drawbacks. The first disadvantage is that the ground coffee begins to lose its freshness and flavor after a few days, so for an optimal espresso the user will also need to have a coffee grinder. Another disadvantage is that the used espresso coffee has to be removed from the filter, which can lead to messiness as the ground is fine.

This led to the development of the ESE coffee pod, which could be used in many espresso machines. Coffee pods are usually individually packaged to maintain freshness, and consist of small pods of perforated filter paper containing the coffee. The pod is placed in a filter holder and then discarded after use. Coffee pods are convenient, but they must fit into the filter holder and positioned correctly, otherwise water can leak around the edges.

This in turn leads to the development of capsule machines. The coffee capsules for these machines are completely sealed. The capsule machine does not use a conventional filter holder. Capsule machines typically have a two-part mechanism. The first portion receives the capsule and has an extraction surface upon which the capsule rests. The second part is provided with a lock lever used to unite the first and second parts. In use, the second portion cuts the upper surface of the capsule to allow water to enter and permeate downwardly through the capsule, wherein the water is directed at a plurality of locations determined by the geometry of the extraction surface. It is expelled through the lower surface of the capsule. Examples of such machines are disclosed in EP 0870457 or WO2005/004683. Capsules in known capsule coffee machines are inserted into a capsule cage of the machine which, in use, holds the capsules in place so that the capsules can be cut by a cutting member.

Capsule machines have proven to be very successful commercially because they are very convenient to use and produce consistent products. However, each manufacturer's coffee machines and capsules are designed to work under the manufacturer's own brand. The most popular brand of capsules is Nespresso®, which uses sealed capsules made of aluminum. In use, the capsule is clamped into position within the machine with the capsule cage portion holding the capsule, so the capsule can be cut by three prongs to allow water, usually under pressure, to enter the coffee capsule. have.

Aluminum has the significant advantage of being impermeable to oxygen and water, which means that the coffee in the capsule has a long shelf life. However, aluminum also has several major disadvantages in that the aluminum deforms easily during the filling and packing steps and it is difficult and expensive to create a reliable seal on the capsule rim. The only known seal that works despite considerable research efforts is the silicone elastomer disclosed in EP1654966. In these capsules, the edge of the aluminum rim is rolled over where the front foil seal is attached. Known solutions to these problems additionally require very high capital investments that most companies cannot.

It has been proposed to use raised ribs formed by extruding material from the capsule rim. These seals are functional but reduce the effective sealing area on the front circumference of the capsule where the capsule is sealed with the foil. This results in an unacceptably high failure rate of the foil seal resulting in degassing of the filled capsules and consequently not fresh coffee.

Attempts to use paper gaskets have also failed for several reasons. Known paper gaskets tend to peel off due to the rapid depressurization of the brew chamber when the handle is lifted over the coffee machine, causing the stacked layers of material to separate and detach from the capsule. An additional type of delamination occurs when the ink printed on the surface forms a water barrier and prevents pressure in the gasket from escaping.

This peeled gasket material can build up on the brew chamber in the machine over time and cause subsequent capsules to leak during brewing and cause short shots/incomplete brewing.

A further problem is that paper gaskets are prone to rupture because they do not have sufficient wet strength to withstand the high pressures encountered during coffee extraction. The gasket collapses in a small area, allowing water to escape and reducing the pressure.

A further problem with aluminum capsules arises from the perforation of the capsule foils that allow water to pass through the coffee for extraction. The size of the orifice affects the flow rate of water into and through the capsule, the larger the hole the greater the flow rate and the smaller the hole the smaller the flow rate. Therefore, controlling the flow rate is important for the quality of the coffee, with a flow rate that is too slow which results in over-extraction and makes the coffee bitter, and a flow rate that is too fast results in too weak extraction and thus unflavored coffee.

Accordingly, it is an object of the present invention to provide an improved coffee capsule.

According to a first aspect of the invention there is provided a capsule for use in a coffee machine according to the characterizing part of claim 1 , the machine having a capsule cage for holding the capsule in the brewing position, the capsule being formed of a soft metal .

Preferred embodiments of the invention are disclosed in the dependent claims.

The seal of the present invention advantageously provides a good seal for capsules and is more readily recycled compared to known silicone seals.

An exemplary embodiment of the present invention will now be described with reference to the drawings.

1a schematically shows a cross-section of a capsule;
1b schematically shows a cross-section of a capsule interacting with a machine blade;
1c schematically shows the brewhead of a coffee machine.
2 shows a perspective view of a capsule;
3A shows a first layered seal.
Figure 3b shows a second layered seal.
Figure 4 shows the laminate structure of the seal.
Fig. 5a schematically shows a first alternative structure.
Figure 5b schematically shows a second alternative structure.

1a shows a cross-section of a capsule 1 having a general frustoconical shape with respect to a body 2 . The upper end 3 of the capsule has a second frustoconical section 4 having a smaller diameter than the lower end. The upper end 3 is additionally provided with an additional frusto-conical indentation 5 in the center of the upper end 3 . The capsule is provided with a flange 7 at the end of the body 2 remote from the upper end 3 .

In order to ensure that the capsule functions effectively in a wide range of capsule coffee machines on the market, the four dimensions, denoted V, W, X and Y, are important and need to be used in cases where problems with insertion and ejection of the capsule within the machine are avoided. .

1B shows an additional dimension for the capsule, ie the distance A between the capsule sealing surface and the surface of the capsule interacting with the machine blade on top of the capsule, FIG. 1C showing the coffee machine brew head or capsule cage sealing surface and blade The dimension B, which is the distance between the tips in (20), is shown. Dimension A depends on the thickness of the seal on the flange, while dimension B is determined by the capsule coffee machine design. The penetration depth of the blade is estimated by subtracting dimension B from dimension A.

2 shows a perspective view of a capsule provided with an annular protruding surface 10 facing outward from the upper surface. The protruding surface 10 may be chamfered or beveled but curved. The protruding surface 10 provides a steeper angle to the blade than the surface 4, which improves entry of the blade. The flange 7 comprises an upright wall 8 , thereby forming a trough 9 between the wall of the capsule and the upstanding wall 8 . The upstanding wall 8 is then curved back down towards the same side as the opening so that the distal end is substantially in the longitudinal plane of the capsule but below the trough 9 . The shape of the distal end forms an open hook. The opening hook receives the seal to close the capsule after packing or filling. The open hook configuration provides the rim of the flange with a plurality of webs that provide some reinforcement so that the foil can be easily attached to a capsule made of a softer, softer material such as aluminum.

The annular surface 10 is raised from the peripheral plane of the capsule surface 12 by between 0.15 mm and 0.35 mm, in a particularly preferred embodiment by 0.25 mm. The surface has a width of about 0.2 to 0.3 mm to allow for tolerances between machines. The angle of the surface to the planar surface of the capsule is between 30° and 34°, with the angle increasing from the center of the capsule to the edge. Within the range of the height of the protruding surface, the blades of the brew head maintain an angle of incidence of about 30° with respect to the planar surface of the capsule 12 . When the angle of incidence of the blade is greater than about 35° or less than about 25°, the capsule tends to deform under the action of the blade rather than penetrate. Within the scope of specific embodiments, hole sizes of 0.95 to 1.05 mm diameter can be achieved, which allows for optimal flow rates for standard espresso grounds.

A seal 9 having a generally annular shape is provided on the flange in the exemplary seal structure shown in FIGS. 3A, 3B and 4 . Exemplary seals include three layers with a layer of chemical (sulphate) pulp or CTMP (chemical-thermomechanical pulp) or a layer of chemical (sulphate) pulp and CTMP (chemical-thermomechanical pulp). The chemical pulping process produces long, well-bonded fibers, which give the material high strength and water resistance.

The material structure also provides good edge wick holdout. The edge wick defines resistance to liquid penetration along the exposed edge of the board, which helps maintain the strength and stiffness of the gasket in use.

PE:

A further exemplary embodiment illustrated in Figures 3A and 3B is a hybrid lamination option, wherein the hybrid concept can be a lamination of an elastic material (e.g., one of foam/plastic/silicone) and an inelastic deformable material (i.e., paper). have. The laminate may be two or more layers, with the paper being the outer or upper layer such that the paper is plastically deformed.

Residual water in the brewhead causes a small amount of swelling of the paper or cellulosic material when the coffee machine is in use, which swelling allows for better bonding with the castellation on the brewhead, which improves the seal.

The seal may be held in place by adhesive or mechanical means.

In a first embodiment, the seal is secured to the flange with an adhesive having a melt range of about 140 degrees, which is well above the 100 degrees seen during coffee brewing, but low enough to be activated for a short dwell time during capsule filling, specifically a starch-based biodegradable adhesive. do. With an elevated sealing head temperature, temperatures of 140 degrees can be reached in that short time.

In alternative embodiments, the gasket may be applied by pressure and/or heat without the use of an adhesive. This could be a dry thermal process or it would be possible to use steam. As pressure and/or heat is applied, the gasket is swaged out and tightened around the inner diameter, creating a tight fit across the capsule. The outer diameter also increases, pressing the gasket against the rim of the capsule.

In a further alternative embodiment, the liquid heat sealable adhesive may be applied directly to the board. It can be used instead of gluing the film to the board, which will help reduce cost and improve recyclability. The liquid heat sealable adhesive is applied with one or more coatings. The first coating acts as a primer and subsequent coatings or coatings are applied to build up a level of thickness on the surface ensuring that not all adhesive is absorbed into the board. An exemplary basis weight of the heat seal adhesive to be applied is 4 to 30 gsm.

For aesthetic reasons, it is preferred to use color matched gaskets for the capsules. Known approaches have the problem of gaskets being attached to the brew chamber during/after extraction when the capsules are ejected. This is because ink softens and is prone to reactivation (softening) when exposed to heat and pressure. Then, upon cooling, the ink and gasket stick to the brew chamber. This may leave all or part of the gasket on the brew chamber, eventually causing build-up leading to leakage during extraction. A printed gasket may also prevent pressure release from the gasket.

In a preferred embodiment, the seal is made as an uncoated board or as a board coated on only one side, and ink is applied to the uncoated side, for example to color match the seal to the capsule body. This approach advantageously allows the ink to seep into the core of the board, lowering the likelihood of delamination. Alternatively, it is possible to apply the pattern to the uncoated side, which splits the printed layer into small fragments, which allow the pressure to escape. Once delamination begins, the pattern reduces the likelihood of delamination spreading. The pattern may include a dotted/dotted line/wavy line and the like. Aesthetically, the pattern can be chosen so that the board appears fully printed.

This can be addressed by laminating over the top of the printed surface, as shown in Figure 4, and the ink is not in direct contact with the brew chamber. Therefore, even if reactivated, the ink cannot stick to the brew chamber.

The capsule wall is provided with a flute extending substantially over the length of the side wall portion 2 of the body. The flutes are concave by 0.1 to 0.3 mm from the maximum outer radius of the side wall 2 . The flutes may be 0.5 to 10 mm wide. The flutes may be disposed substantially continuously within the sidewall.

Surprisingly, it has been found that the provision of flutes extending over a significant portion of the sidewall 2 greatly increases the strength of the capsule, making the capsule much less likely to deform. The fluted design capsule requires a force of 20N to deform the side of the capsule by 2.0 mm, whereas the known capsule requires a force of 10N to 15N. The force is applied 1/3 above the gasket sealing surface in a direction perpendicular to the axis of the capsule using a 9.0 mm diameter pad. This greatly improves the ease of handling capsules, both in the manufacture of the capsules and in their filling. It is also less likely to be damaged during transport. This will reduce waste in capsule production and facilitate the wider use of aluminum capsules, which is desirable over plastics with respect to recyclability.

In the capsule of the present invention, the aluminum has a thickness of 0.075 to 0.125 mm.

5a shows an alternative configuration of the seal in which the annular seal 9 is provided with an annular groove or concave rib 15 . A corresponding annular groove 16 is formed on the annular flange of the capsule. The annular groove 16 may receive the capsule cage of the coffee machine.

FIG. 5B shows an alternative arrangement to that of FIG. 5A , wherein the seal is provided with an annular projection or convex rib 17 . The annular flange is provided with corresponding projections or ribs 18 . In use, the capsule cage of the coffee machine may be coupled to the protrusion to form a seal.

Although the capsules have been specifically described as being used for making espresso coffee, it is possible to use the capsules for making other beverage capsules such as tea or chocolate.

Claims (15)

A capsule for use in a coffee machine having a brew chamber, the capsule having a generally frustoconical shape having an upper surface and a lower surface, an annular flange provided on the lower surface, and comprising a paper-like cellulosic material that plastically deforms in use. A capsule comprising an annular seal provided on the annular flange, the annular seal comprising first and second layers, the first layer comprising elongate well-bonded fibers. The capsule of claim 1 , wherein the second layer comprises an elastically compressible material. 3. The capsule of claim 1 or 2, wherein the seal further comprises a layer for adhesive for attaching the seal to the capsule rim. 4 . The capsule according to claim 1 , wherein the first layer is formed from chemical (sulphate) pulp or CTMP (chemical-thermomechanical pulp). 5. The capsule of any one of claims 1 to 4, wherein the seal comprises a layer of liquid heat sealable adhesive. 6. The capsule of any one of claims 3-5, wherein the adhesive is a starch-based biodegradable adhesive having a melting range of about 140°C. 3. The seal according to claim 1 or 2, wherein the seal is applied by pressure and/or heat without the use of adhesive, and as pressure and/or heat is applied, the gasket is swaged and tightened around the inner diameter of the seal to form the seal on the capsule. A capsule that holds the seal in place. 8. The capsule according to any one of the preceding claims, wherein the seal is made of an uncoated board or of a board coated on only one side and the ink is applied on the uncoated side. 9. A capsule according to any one of the preceding claims, wherein a pattern is applied to the uncoated side of the seal, the pattern splitting the printed layer into small pieces to release pressure. 10. A capsule according to claim 8 or 9, wherein the seal is laminated over the top of the printed surface such that the ink does not come into direct contact with the brew chamber of the coffee machine. 11 . The capsule according to claim 1 , wherein the edge wick is less than 5 mm in an edge wick test in hot water at 95° C. for 10 minutes. 12. The capsule according to any one of claims 1 to 11, wherein the seal has a tear resistance of 3000 to 5000 mN and an internal bond strength of at least 90 J/m ² . 13. A capsule according to any one of the preceding claims, wherein the seal has an annular groove for receiving the coffee machine's capsule cage or brewhead, thereby providing a sealing fit. 13. A capsule according to any one of the preceding claims, wherein the seal has an annular projection for engagement with the coffee machine's capsule cage or brewhead, thereby providing a sealing engagement. 15. A capsule according to claim 13 or 14, wherein the flanges have corresponding grooves or projections.

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