Capsule for holding coffee powder

Abstract

The invention relates to a capsule for holding coffee powder and for producing a coffee beverage with the aid of water in a device holding the capsule, wherein the capsule has a container (1) with an interior space accessible via an opening and a lid (2) for the reversible opening and closing of the opening by a user, a snap-action disc (4) is arranged on the container (1) and / or on the lid (2), which snap-action disc is designed such that it is in a non-snap-open state below a predetermined pressure in the capsule and in a snap-open state above the predetermined pressure in the capsule, and the snap-action disc (4) is designed and arranged such that, in the non-snap-open state, it seals the interior space of the capsule from the outside and, in the snap-open state, opens an opening to the outside which allows the coffee beverage to escape from the interior of the capsule to the outside.In this way, a simple and efficient capsule is provided for receiving coffee powder and for producing a high-quality coffee beverage with the aid of water in a device receiving the capsule.

Description

The present invention relates to a capsule for containing coffee powder and for producing a coffee beverage by means of water in a device containing the capsule, the capsule comprising a container having an interior space accessible via an opening and a lid for reversibly opening and closing the opening by a user.Capsule coffee machines have found wide spread. In addition to the first supplier of capsule coffee machines and disposable capsules, many suppliers have meanwhile been working on the market, which offer either their own disposable systems or disposable capsules that are compatible with capsule coffee machines of other suppliers. Disposable capsules can consist of metal or plastic or of both materials. Due to the small amount of usually about 5.5 g coffee per capsule, the amount of metal and plastic waste per kilogram coffee powder is relatively large, since the disposable capsules must be disposed of after one use.Disposable capsules usually consist of a container which is filled with coffee powder and of a lid for closing the container after it has been filled with coffee powder. They usually have a peripheral flange which can be clamped between two seats in the associated capsule coffee machine in order to form at least one closed space which lies on one side of the flange. The flange is usually arranged on the side of the container which is closed by the lid. During the brewing process, water is introduced into this closed space, usually under elevated pressure with respect to ambient pressure, in order to flow through the inlet openings into the disposable capsule and through the coffee powder in order to mix with the latter and to dissolve substances out of the coffee powder. The maximum water pressure attainable in typical capsule coffee machines is usually between 3 and 25 bar.Usually on the side of the disposable capsule which lies on the other side of the clamped flange, the prepared coffee beverage exits the disposable capsule again. For this purpose, the disposable capsules usually have a cover which is designed as a thin membrane made of aluminum or plastic and which tears in the capsule during the brewing process when a specific pressure is reached, wherein the cracks serve as outlet openings for the coffee beverage. For this purpose, the membrane can usually contact a relief pane which, due to its shape, assists the tearing open relatively precisely at a specific pressure.As an alternative to disposable capsules, refillable capsules have also been offered by various manufacturers for some years. These refillable capsules are compatible with disposable capsules and compatible with capsule coffee machines intended for disposable capsules, respectively. The advantage of these refillable capsules is the reduced amount of waste and the possibility of being able to select the coffee itself, whereby the costs per portion can be considerably reduced or one can deliberately use a certain type of coffee.The basic principle of many refillable capsules is that they consist of at least two parts, the container for containing the coffee powder and a lid as a cover for closing the container after its filling with coffee powder, which lid can be connected to the container to enclose the coffee powder. Containers or lids are often not closed, but rather have inlet openings for allowing the water to pass into the capsule during the brewing process and outlet openings for allowing the finished coffee beverage to exit from the capsule.In their basic form, refillable capsules usually correspond to the disposable capsule for which they are to serve as a refillable alternative, or to the corresponding accommodation geometry in the matching capsule coffee machine, in order to obtain the largest possible volume for the coffee powder close to that of the disposable capsule. In this case, a refillable capsule usually has recesses opposite the disposable capsule at the locations at which parts of the capsule coffee machine penetrate into the disposable capsule when the disposable capsule is inserted into the capsule coffee machine and the latter has been closed. These may be, for example, structures which pierce the disposable capsule to form an inlet opening for the water. If the refillable capsule is rotationally symmetrical and can thus be inserted into the capsule coffee machine in any desired orientation, then such recesses must also be rotationally symmetrical, for example as an annular groove, in order to prevent contact of the structures with the capsule in any possible insertion position of the capsule into the capsule coffee machine. An example of a refillable capsule is described in the document EP 2 604 151 B1.The inlet openings in the case of refillable capsules are usually located on one side of the flange and the outlet openings for the coffee beverage are located on the other side of the flange. In any event, the side of the capsule on which the water is introduced into it must be sealed against the refill capsule receptacle in the capsule coffee machine in order for the water to flow through the capsule and not past the capsule. For this purpose, the flange of a refillable capsule is generally clamped between two parts of the capsule coffee machine, in order to form on one side of the flange a closed space, into which water is introduced and then can flow through the inlet openings into the refillable capsules.EP 2 483 177 B1 proposes a coffee capsule which is suitable for the preparation of a coffee beverage in a beverage machine and is provided with a thin-walled, frustoconical housing part and with a base part provided with inflow openings for an extraction fluid and with a cover part having at least one outlet opening. The outlet opening of the cover part is covered with a membrane permanently connected to the cover part and having a plurality of perforations.EP 3 088 330 A1 describes a capsule for beverages which consists of a housing which is closed with barriers which can be pierced at the top and at the bottom and is intended for the preparation of hot, liquid foods, in particular beverages such as cappuccino and coffee. The capsule is characterized in that inside a casing, at the level of the upper part of the casing, between an upper barrier and the surface of a separator which is sealingly connected along its periphery to the inner surface of the casing, there is a bushing provided at the base with openings for the outflow of the liquid for mixing the substances in the direction from the separator to the upper barrier, and the outflow from each hole of the separator is controlled by a pressure regulating valve.CH 708 662 A1 discloses a capsule having a preferably rotationally symmetrical capsule body with a side wall and a base formed in particular integrally therewith, and having a cover which covers the capsule body for forming a closed chamber which contains a substance for the preparation of a liquid foodstuff. The capsule has an outlet opening for dispensing the liquid foodstuff in the region of the base. The outlet opening is closed with a valve, wherein the valve has a valve opening and is designed in such a way that the valve opening is open under a working pressure prevailing in the capsule and the valve opening is closed in a pressure-free rest state.WO 2015 / 173375 A1 describes a beverage capsule comprising: a container defining a chamber for storing beverage material, wherein the container is designed such that a fluid entering the chamber can build up a pressure, and a valve means which can be switched from a first setting in which the discharge of pressurized fluid from the chamber is prevented to a second setting in which the discharge of pressurized fluid from the chamber is permitted, wherein the valve means can subsequently be switched from the second setting to the first setting.CN 2 19 135 145 U provides a food capsule and a device for preparing beverages. The food capsule comprises a capsule shell, a piercing structure and a capsule bottom structure. The capsule shell is provided with a receiving cavity, and a liquid outlet is formed in the lower end of the capsule shell. The bottom structure of the capsule comprises a deformable bottom and a first sealing film. The deformable bottom covers the liquid outlet, and a through hole corresponding to the piercing structure is formed in the deformable bottom. The first sealing film covers the through hole to isolate the liquid outlet from the food to be scalded, and the deformable bottom has a first state in which the deformable bottom protrudes upward to be removed from the piercing structure. When the deformable bottom is in the second state, the piercing structure pierces the first sealing film, so that the brewing liquid in the receiving cavity is discharged through the through hole and the liquid outlet one by one.US 2016 / 0 145 038 A1 describes various beverage preparation systems, beverage capsules and beverage preparation machines. In some embodiments, a beverage capsule for preparing a single portion of beverage comprises a portion containing whole coffee beans. The capsule may include a movable grinding element disposed in the section. The movable grinding element may be constructed to move relative to the section and to grind the coffee beans into coffee grounds within the beverage capsule. The capsule may have an inlet configured for the supply of liquid. The liquid may mix with the coffee grounds to prepare the beverage inside the capsule. The beverage can be dispensed through an outlet, for example directly into a cup.WO 2014 / 053 614 A1 relates to a beverage capsule comprising a capsule body having an outlet, a plug configured to mate with the outlet, and an opening device made at least partially of a shape memory alloy and biased to maintain the plug in the outlet in a first closed position and configured to release from the first closed position when heated above the transition temperature of the shape memory alloy, thereby retracting the plug from the outlet to a second open position and allowing fluid communication through the outlet.It is the object of the invention to provide a capsule which can be used easily and efficiently for receiving coffee powder and for producing a high-quality coffee beverage with the aid of water in a device which receives the capsule.LiquidThis object is achieved by the subject matter of claim 1. Preferred developments of the invention are described in the dependent claims.Features of a high quality coffee beverage from a capsule are a good taste, a good consistency and, in the case of an espresso type coffee beverage, sufficiently frothy components, the so-called crema. These characteristics depend on the coffee grade, the amount of coffee powder filled into the capsule, its freeness and the resulting various particle sizes and their proportions in the coffee powder, and the compression of the coffee powder in the capsule before the brewing process.It is also important in particular how the water flows through the capsule during the brewing process, in particular in the case of a coffee beverage of the type Espresso. When the brewing process is started in a capsule coffee machine, heated water is conducted under elevated pressure into the capsule. The capsule should only open when a certain pressure is reached in the capsule and form an outlet opening for the coffee beverage. Until opening, the water or the coffee beverage formed does not yet leave the capsule, but rather collects in the capsule, wets through the coffee powder located therein or mixes with it and allows it to swell.Ideally, the complete coffee powder is moistened and fills the interior of the capsule completely and with uniform compaction before opening occurs and the actual so-called extraction of the coffee beverage begins. As a result, the now moistened and swollen coffee powder is flowed through more uniformly by the water during the extraction. Channels can also be formed in the coffee powder less easily, through which the water entering the capsule flows too quickly to the outlet openings without coming into sufficient contact with the entire coffee powder. The previously described effect of water and coffee powder mixing before extraction occurs is also called pre-infusion. When the term pre-infusion is used hereinafter, it means the effect described above. Pre-infusion provides an improved taste, consistency and more so-called crema in the prepared coffee beverage, in particular an Espresso type beverage.For an optimum coffee from a capsule, the following should therefore be observed: the outlet opening of the capsule should remain closed during the brewing process until a specific pressure is reached in the capsule. After opening, the outlet opening should be open at considerably less pressure than is necessary for opening or even remain open without pressure, so that the coffee beverage can pass through the outlet opening at the smallest possible flow rate. The volume in the capsule available for coffee powder should otherwise be as large as possible or the space requirement for the closure mechanism of the outlet opening should be as small as possible.All of this addresses the present invention in a simple and efficient manner.In the present case, the terms listed below are understood as explained below."Brewing" means the preparation of a coffee beverage with a capsule coffee machine, this term including pre-infusion and extraction."Extraction" means the extraction of the aroma and flavouring substances from the coffee powder by passing heated water under elevated pressure through the coffee powder and, after accumulation with the dissolved aroma and flavouring substances, flowing out of the coffee powder as a coffee beverage."Coffee powder" means roasted and ground coffee beans and products containing roasted and ground coffee beans."Coffee beverage" means any beverage that arises by passing cold or heated water through and interacting with coffee powder, without pressure or at elevated pressure relative to ambient pressure."Capsule" means any type of container which is provided for holding coffee powder and for preparing a coffee beverage by introducing cold or heated water which interacts with the coffee powder in the capsule and then exits the capsule again as coffee beverage into a capsule coffee machine provided for holding the capsule. The term "capsule" here comprises both disposable capsules which have to be disposed of after one use and refillable capsules which can be filled several times with fresh coffee powder. If only one of the two embodiments is explicitly meant, the term "disposable capsule" or "fillable capsule" is used instead of capsule. It also includes all parts which are necessary for the preparation of a coffee beverage and are firmly connected or separate from the capsule, such as in particular seals for sealing the capsule against the capsule coffee machine or for sealing the lid against the capsule. The terms "capsule", "disposable capsule" and "fillable capsule" can refer both to the still unsealed capsule having an opening for filling the coffee powder and to the capsule already filled and sealed with coffee powder."Capsule coffee machine" means any device for preparing a coffee beverage which is provided for receiving capsules and in which the preparation is effected by passing water through a coffee powder located in a capsule. This includes cold and heated water and the passage without or with increased pressure of the water."Opening pressure" means the pressure in the capsule during the brewing process from which the valve opening opens. In the case of a snap-action disc or bimetallic snap-action disc, the snap-action force of the snap-action disc or bimetallic snap-action disc corresponds to the opening pressure.The term "profiled" means in the present case "extending linearly with constant cross section"."Relief disc" means a surface in a capsule coffee machine, against which the surface of a disposable capsule abuts, in which the outlet openings in the disposable capsule arise or are introduced during the preparation of a coffee beverage. This is usually done in that the water introduced under pressure into the capsule presses the surface of the capsule against the relief pane and when a certain pressure is reached the surface of the capsule is torn at the relief pane. This occurs because the relief disc has raised and depressed areas, for example in the form of truncated pyramid shapes, and the surface tears when pressed into the depressions."Outlet opening" or "outlet openings" means one or more openings in a capsule through which coffee beverage can exit the capsule."Container" means that part of a capsule which, due to its shape, can contain the coffee powder."Lid" means that portion of a capsule which, by connection to the container, closes the capsule."Inlet ports" means an opening or openings in containers or lids through which water can enter a capsule for the preparation of a coffee beverage."Elastically deformable" means the deformability of a component by applying a force, wherein the deformed component opposes a force to the applied force, as in the case of a spring, and that the component returns to its initial shape again after removing the applied force, as in the case of a spring."Disc with a formation" means a separate component or part of container or lid which has a formation which, due to its shape, can bear so tightly against a valve opening that it is closed, which in this case means that the pressure inside the capsule can rise during the brewing process until the opening pressure is reached and from here on a considerably larger cross section of the valve opening becomes free. The disc can also have a plurality of formations in order to close a plurality of valve openings."Screen disk" means a separate part or part of container or lid which, when the capsule is closed, separates the coffee powder in the capsule from the snap disk."Valve opening" means an opening in a separate part or part of container or lid, which can be closed by a closure element, here in particular a formation on a disc with a formation or a valve pin, namely so tightly that the pressure in the interior of the capsule can increase during the brewing process until the opening pressure is reached and from here the valve opening opens and a considerably larger cross section of the valve opening becomes free."Valve pin" means a separate part or part which is fastened to the screen disk, or an integral part of the screen disk which, at least at one point, has a profile-like cross section which corresponds to the shape of the valve opening and which projects into the latter and thereby closes it, and which can be moved with its complete profile-like cross section into and out of the valve opening with little play, but freely."Snap disc" means a circular or other shaped disc having a bulge extending over the entire disc or only a part, the bulge snapping over by applying a force to the bulge from reaching the snapping force and thereafter remaining snapped over by applying a force smaller than the snapping force until the snap-back force is undershot and the bulge snapping back into the initial shape."Bimetallic snap disc" means a snap disc which, when the snap-over temperature is reached, snaps over without the application of a force from the outside, and remains snapped over as long as it does not fall below the snap-over temperature. If the snapping over is triggered by applying a force to the curvature below the snapping over temperature but above the snap-back temperature, the snap-back disc remains snapped over by itself, even without further application of a force to the curvature, as long as the snap-back temperature is not fallen below."Snap-back force" means the force on the curvature of a snapped-back snap-on disc, which must be undershot in order for the curvature to snap back against the snap-back force. The snap-back force is significantly lower than the snap-over force."Snap-back temperature" means the temperature at which a snapped-back bimetallic snap disc snaps back again by itself, i.e. without application of a force."Snap-over force" means the force that must be applied to the arch of a snap-over disc in order for the arch to snap over. In the case of a "bimetallic snap disc", the snap-over force decreases with increasing temperature."Snap-over point" means the point up to which the curvature of a snap-over disc has to be pressed in by applying the snap-over force to the curvature, so that it can be snapped over from this point by applying a force which is then significantly smaller and also to remain snapped over on further application of the significantly smaller force. In the case of a bimetallic snap disc, the term also means the point to which it deforms slowly when it is heated before it snaps over rapidly by itself when the snap-over temperature is reached."Snap-over temperature" means the temperature at which a bimetallic snap-over disc snaps over by itself, i.e. without application of a force.It is an essential aspect of the invention that the capsule is equipped with a snap disc. Snap-action disks are known per se from the prior art. Snap-action disks are used, for example, in electrical tactile switches (tactile switches) for generating tactile feedback. Bimetallic snap-action disks are used, for example, in thermal switches (snap-action thermostats) for switching a circuit when a specific temperature is reached.The valve opening can be arranged in the snap-action disc and be closed by a further component or the valve opening can be located in a component other than the snap-action disc and be closed by the snap-action disc. In both cases, the opening of the valve takes place by snapping over the snap disc, which is triggered by a certain pressure of the water introduced into the capsule being reached against the snap disc.The solution according to the invention can be implemented both with one valve opening and with a plurality of valve openings, even if only one embodiment with a single or only one embodiment with a plurality of valve openings is discussed in the description of the individual solutions and exemplary embodiments.In addition to the use of a snap-in disc, the use of a plurality of snap-in discs is also possible, even if only one embodiment with a snap-in disc is discussed in the description of the individual solutions and exemplary embodiments.By appropriate design of the snap-action disc, the opening pressure at which the valve opening is intended to open or at which the snap-action disc snaps over can be determined.In the case of a snap-action disc, the valve opening opens abruptly when the opening pressure, which corresponds to the snap-action force of the snap-action disc, is reached, and the valve opening remains open as long as the pressure in the capsule on the snap-action disc is so high that the snap-action force is not undershot.In the case of a snap-action disc as a bimetallic snap-action disc, the valve also opens abruptly when the opening pressure, which corresponds to the snap-action force of the snap-action disc, is reached. It remains snapped over after the snapping over even if no pressure in the capsule acts on the snap disc until the bimetallic snap disc has fallen below the snap-back temperature, provided that this was exceeded during the snapping over. If this is not the case during the snapping over, the bimetallic snap-action disc behaves like a snap-action disc which is not a bimetallic snap-action disc, and snaps back as soon as the snap-back force is undershot.An embodiment is preferred in which the snap-over is triggered by reaching a certain pressure in the capsule and the bimetallic snap-over disc remains snapped over after the snap-over, so that the coffee beverage can flow out through the valve without pressure against the snap-over disc. For this purpose, the snap-back temperature must be reliably exceeded during the brewing process. The snap-over temperature, on the other hand, should never be reached so that the bimetallic snap-over disc is snapped over only by the pressure in the capsule and not by reaching a certain temperature. As the temperature rises, the snap-over force of a bimetallic snap-action disc decreases until the snap-over action takes place automatically when the snap-over temperature is reached. The bimetallic snap disc is therefore preferably designed such that it snaps over when it has reached a temperature typical during the brewing process by the water flowing into the capsule and the pressure in the capsule has reached the desired opening pressure. The snap-over force or the snap-over temperature can be designed to the desired values for the snap-over force at a specific temperature by the size of the pane, the material, the thickness and the depth of the curvature. By the introduction of radially or concentrically embossed ribs, the stiffness can be increased, which enables a flatter bulge or a smaller material thickness with the same snap-over force and thus a smaller installation space.The solution according to the invention is preferably implemented in the case of refillable capsules with a container and lid shaped in a rotationally symmetrical manner. For this variant, embodiments are described which, however, can be implemented in the same form even in the case of a differently shaped container and lid, for example rectangular or polygonal ones.The solution according to the invention can preferably be implemented for refillable capsules having a diameter in the region of the connection of container and lid of 25 mm to 75 mm, preferably of 32 mm to 60 mm, and a total height of the capsule, measured vertically to the connection plane of container and lid of 12 mm to 60 mm, preferably 20 mm to 42 mm. As material for the container and the lid, it is preferably possible to use metal, but also plastic or one material for the lid and the other for the container. The solution according to the invention is independent of the type of connection of container and lid. All the following embodiments of the solution according to the invention show a cover which is designed as a round turned part and which accommodates the further components in a concentric opening in its center. There are further possible embodiments in which, for example, the solution according to the invention is accommodated in the container instead of in the lid, or in which the lid can be designed not as a turned part but as a sheet metal formed part and then optionally also the snap disc or the screen disc can be an integral component of the lid.Hereinafter, the individual components will be described in the order in which they are inserted into the refillable capsule. In one possible embodiment, a screen disk is located in the lid or in the container of a refillable capsule, which screen disk can be a separate part or an integral component of the lid or container. It is preferably arranged on the side of a refillable capsule, which during the brewing process abuts the relief disc of the capsule coffee machine. It can be firmly connected to the cover or container as a separate component, or can be removed and re-inserted by the user. If it is removable, it should then lie so tightly against the component in which it is mounted, i.e. the cover or container, that no coffee powder can pass through the gap between it and the component receiving it.It is intended to absorb the pressure of the coffee powder which expands during moistening with water, without deforming strongly in the process, since the position of a valve pin connected to it, which closes the valve opening, then changes relative to the snap-action disc and thus also the opening pressure. This includes the pressure which the moistened coffee powder exerts on the screen disk during the brewing process because it opposes the water introduced under pressure with a flow resistance which leads to a force which corresponds to the maximum pressure of the coffee machine multiplied by the projected contact surface of the coffee powder on the screen disk.The stiffer the screen disk, the less the required stroke of the snap disk until the snap point is reached, since it has to be able to compensate for less theoretically possible deformation of the screen disk. For this purpose, it can have inherent rigidity by suitable shaping, for example by having the shape of a dome which bulges into the interior of the capsule in the direction of the coffee powder and is supported at the edge on the cover or container component receiving it. The inherent stiffness can also be influenced by the choice of material. Metal or plastic, preferably a stainless steel of higher strength, can be used in order to make it as thin as possible. Instead of increasing the rigidity of the screen disk, the valve pin can also project further into the valve opening than is necessary for the opening at the desired opening pressure and protrude on the other side of the snap disk as far as a structure of the capsule coffee machine, for example the relief disk, in order to bear against the latter. The valve pin must then have a significantly smaller cross section in the further protruding part in order to achieve a sufficiently large cross section of the open valve opening. The transition between the part of the valve pin with a profile-like cross section and the further protruding part with a significantly smaller cross section can be embodied with sharp edges or as a rounded transition to the significantly smaller cross section. The dimension of the significantly smaller cross-section relative to the cross-section of the valve opening is dependent on the required open cross-section of the valve opening, which should be similar to the cross-section of the openings in the capsule coffee machine for the outflow of the prepared coffee beverage.The screen disk as a separate component is preferably round, but it can also have a different shape. The size of the individual openings in the screen disc depends on the particle size of the coffee powder provided for retaining it. It can be between 0.05 mm and 0.7 mm, preferably between 0.2 mm and 0.4 mm.On the side of the screen disk facing away from the interior of the capsule, a snap disk is arranged, which encloses the coffee powder and the screen disk in the capsule when the container and the lid of the capsule are connected. It is preferably a separate part, but can also be an integral component of the lid or container. In the snap disc there is a valve opening which is preferably round, but can also have a different shape. The valve opening is closed by the valve pin, which may be a separate part, is attached as a separate part to the screen disk, or may be an integral part of the screen disk. The profile-like cross section of the valve pin must project so far into the valve opening that, taking all tolerances into account, it always reaches at least as far as the snap-over point of the snap-on disk. This ensures that the valve opening is first opened and thus the pressure inside the capsule falls when the snap-action disc has passed the snap-action point and only a significantly lower pressure is necessary in order to keep it in the state, or, in the case of a bimetallic snap-action disc, it reaches the fully snapped-action position without pressure and remains when it has exceeded the snap-action temperature during the snap-action.The valve pin preferably has a round shape, but can also be shaped differently. In the region over which the valve opening moves, it must have a profile-like cross section, i.e. a cylindrical shape in the preferred round shape of the valve opening.In order to achieve the above-described necessary tightness of the closed valve opening, the width of the gap between the profile-like cross section of the valve pin and the valve opening in the snap disc should preferably be between 0.005 mm and 0.15 mm, preferably between 0.02 mm and 0.05 mm, depending on the size of the profile-like cross section and thus on the overall length of the gap.During the brewing process, water is conducted under pressure into the capsule, which water flows through the coffee powder, can pass through the screen disc and finally presses and heats the snap disc outwards with increasing pressure in the capsule. When the opening pressure is reached, the snap disc snaps over, so that the part of the valve pin with profile-like cross section is no longer located in the valve opening and a larger gap now becomes free.In a further possible embodiment, a screen disk is located in the lid or in the container of a refillable capsule, as described in the "valve pin" solution. The difference is that no valve pin is connected to the screen disk. On the side of the screen disk facing away from the interior of the capsule, a snap disk is arranged, as described in the solution valve pin. Between the screen disk and the snap disk there is an elastically deformable disk with a formation which can close the valve opening in the snap disk when, after assembly in the cover or in the container of a capsule, it is pressed against the latter due to its elastic deformation. The shape can preferably have the shape of a spherical cap or that of a cone or another shape.For this purpose, the shaping must fit the shape of the valve opening, so that a sufficiently small gap is formed between the shaping and the valve opening. In order to achieve the above-described necessary tightness of the closed valve opening, the width of the gap should be between 0 mm and 0.15 mm, preferably between 0.01 mm and 0.05 mm, depending on the size of the cross section of the valve opening. To improve the seal between the formation and the valve opening, an elastomer material can also be applied partially or completely to the side of the snap-action disc on which the formation bears. This allows greater tolerances during valve opening and forming. The thickness of the elastomer can be between 0.1 mm and 1 mm, preferably 0.2 mm to 0.5 mm. The pane with a shaped portion can preferably be a separate part or integral part of the lid or container. The disk with a shaped portion should be designed such that coffee beverage can pass during the brewing process from the side with the screen disk to the side with the snap disk. For this purpose, the pane with a shaped portion can have openings or cut-outs at the edge.During the brewing process, water is conducted under pressure into the capsule, through which the coffee powder flows, can pass the screen disc and the disc with a shaping and presses against the snap disc and heats the latter. When the opening pressure is reached, the snap-action disc snaps over, wherein the formation of the disc with a formation is pressed against the valve opening and closes the latter until the snap-action disc passes the snap-action point, the formation of the disc with a formation then strikes against a stop and the valve opening in the snap-action disc opens when the snap-action disc is pressed further beyond the snap-action point, or, in the case of a bimetallic snap-action disc, it is deformed further by itself into the snapped-over end position.A surface of the capsule coffee machine can serve as a stop for the shaping. A further possible embodiment is a stop in the capsule itself. For this purpose, when the opening pressure is reached, the formation must be prevented from resting further on the valve opening and closing it when the snap-action disc has passed the snap-action point during the snapping-over.In a further possible embodiment, a screen disk is located in the lid or in the container of a refillable capsule, as described in the "valve pin" solution. The difference is that no valve pin is connected to the screen disk. On the side of the screen disk facing away from the interior of the capsule, a disk with an outlet opening is arranged, which encloses the coffee powder and the screen disk in the capsule when the container and lid of the capsule are connected. It is preferably a separate part, but can also be an integral component of the lid or container. The outlet opening is preferably round, but can also have a different shape. An embodiment with several outlet openings is also possible.Between the screen disc and the disc with the outlet opening there is a bimetallic snap disc. The bimetallic snap disc is pressed against a circumferential bead in the orifice disc within which the orifice or orifices are located. For this purpose, the curvature of the bimetallic snap-action disc must fit the curvature of the circumferential bead, so that a sufficiently small gap is produced when the bimetallic snap-action disc rests on the circumferential bead or the latter is pressed thereon. Preferably, the curvature of the bimetallic snap-action disc is rotationally symmetrical and the shape of the encircling bead is correspondingly circular.In order to achieve the necessary tightness described above in the closed state, the width of the gap should be between 0 mm and 0.15 mm, preferably between 0.005 mm and 0.05 mm, depending on the diameter of the circumferential bead. To improve the seal between the encircling bead and the snap-action disc, an elastomer can be applied partially or completely to the side of the snap-action disc which bears against the closure element or against the contact surface in the interior of the capsule. This allows greater tolerances with a circumferential bead and snap-fit disc. The thickness of the elastomer can be between 0.1 mm and 1 mm, preferably 0.2 mm to 0.5 mm.The outlet opening should be designed such that when the bimetallic snap-action disc rests on the edge of the outlet opening after snapping over, coffee beverage can nevertheless still flow through between it and the edge of the outlet opening. For this purpose, the edge of the outlet opening can be corrugated up and down, or the outlet opening can have a shape which is different from the section of the bimetallic snap disc which rests on it.The bimetallic snap disc is to be pressed with sufficient pressure against the circumferential bead in the orifice disc to remain closed until the orifice pressure is reached. This can be achieved in that the space between the screen disk and the disk with the outlet opening is somewhat lower than the height of the bimetallic snap-action disk and the latter thus bears under prestress against the circumferential bead and against the screen disk. The bimetallic snap-action disc can preferably be a separate part or integral part of the cover or container.If the bimetallic snap disc does not have cut-outs at the edge, the screen disc, which presses the bimetallic snap disc against the disc with outlet opening, must have formations in the direction of the bimetallic snap disc, on which the bimetallic snap disc can be supported, so that coffee beverage can flow through the gap between the formations.During the brewing process, water is conducted under pressure into the capsule, through which the coffee powder can pass, can pass through the screen disc, and with increasing pressure in the capsule presses against the bimetallic snap disc and heats the latter. When the opening pressure is reached, the bimetallic snap disc snaps over, then no longer rests on the circumferential bead and opens the path to the outlet opening.The invention is explained in more detail below with reference to drawings which merely represent exemplary embodiments. In the drawings, FIG. 1a shows a preferred embodiment of the "valve pin" solution, wherein the dashed line shows the position of the valve disc and the disc with a formation when the valve opening is open, FIG. 1 bshows a partially cut-away perspective view of FIG. 1 a, FIG. 2 shows a preferred embodiment of the "shaping" solution as a section of a side view, wherein the dashed line shows the position of the valve disk and of the disk with a shaping when the valve opening is open, FIG. 3 ashows a further preferred embodiment of the "shaping" solution as a section of a side view, wherein the dashed line shows the position of the valve disk and the disk with a shaping when the valve opening is open, FIG. 3 bshows a view in the direction of the axis of rotation of the pin in the disc with a formation, and FIG. 4 shows a preferred embodiment of the solution "snap disc without hole" as a section of a side view of a capsule, wherein the dashed line shows the position of the bimetallic snap disc when the valve opening is open.For a better understanding, only the cut surface of the screen disk is shown in FIGS. 1 a, 2, 3 aand 4, but not the edges of the wall sections and the openings in the screen disk.FIG. 1 ashows a preferred embodiment of the solution "valve pin" as a section in a side view. For a better understanding, only the cut surface of the screen disk is shown. The dashed line shows the position of the snap disc when the valve opening is open. FIG. 1 bshows a partially cut-away perspective view of FIG. 1 a.A screen disk 3 and a snap disk 4 are arranged in the cover 2 of a capsule which is manufactured as an annular rotating part from metal. At its outer edge, the cover 2 has a flange 14 which receives a seal 10. On its inner edge, the cover 2 has a circumferential step 13, on which the snap disc 4 rests. At the outer edge of the step 13 there is a conical peripheral wall which has at its upper end an inwardly projecting peripheral bead 12 against which the wall portions of the screen disc 3 are supported. On the outside there is a circumferential groove 11 into which the container 1 with inlet openings 16 provided therein can engage when it is to be connected to the lid 2. For this purpose, the container has gill-like cut-outs at two mutually opposite points in the direction of the container interior. These can latch into the groove when they are pressed over the conical circumferential wall and the open part of the container thereby deforms into an oval. The edge of the container can be pressed against the seal 10 in the locked state in such a way that the connection between container and lid is sealed. Alternatively, the conical peripheral wall can be set back at its upper end at two mutually opposite locations, namely up to the depth of the peripheral groove 11 and somewhat wider than the gill-like cut-outs, so that the container can be placed on the lid without deformation and, by a rotation relative to the lid, the gill-like cut-outs lie in the groove next to the set-back locations, in the sense of a bayonet lock.The snap disc 4 is formed with a valve opening 6 in the middle. The snap disc 4 can be produced by punching, and the valve opening 6 in the middle can be fine-cut with the necessary tolerance. The screen disk 3 has the shape of a rotationally symmetrical dome and is made of stainless spring steel. On the outer edge of the dome-shaped region, it has a conical encircling wall which opens upwards and which has sixteen radial incisions all around, of which two are situated alternately in each case only in the encircling wall and two extend into the dome a distance of two in each case a few millimetres. The wall sections between the cuts extending far into the dome are bent slightly upwards compared to the other wall sections in the dome and act like a spring, the upper edge of which can spring in parallel to the axis of rotation of the dome as well as vertically to it. The wall sections between the notches located only in the circumferential wall, on the other hand, act like a spring, the upper edge of which can spring only vertically to the axis of rotation of the dome. The valve pin 5 is designed as an integral part of the screen disk 3, which can be done during the production of the screen disk 3 by means of deep drawing. The outer contour and the openings in the screen disk 3 can be produced by punching and the final shape of the dome and the circumferential wall sections can be produced by pressing.When the cover 2 is assembled, the snap-fit disc 4 is placed on the circumferential step 13 in the cover 2. The screen disk 3 is pressed onto the snap disk 4 by the inwardly projecting circumferential bead 12 on the cover 2, wherein the valve pin 5 on the screen disk 3 must find it into the valve opening 6 in the snap disk 4. First, the wall portions of the screen disk 3 catch under the circumferential bead 12 which are not bent upward. By pressing on the four upwardly bent wall sections of the screen disk 3, these are pressed downward, then also latch under the circumferential bead 12 and press the outer edge of the dome-shaped region of the screen disk 3 against the snap disk 4 and the latter against the circumferential step 13 in the cover 2.The surface on the circumferential bead 12 behind which the wall sections of the screen disk 3 engage is designed obliquely. The angle is dimensioned such that the upper edges of the wall sections of the screen disk 3 press outwards as far as possible by their spring action until they lie at the end of the oblique surface on the circumferential bead 12. Removal of the screen disk 3 and the snap disk 4 takes place by pressure against the snap disk 4 in the direction of the interior of the capsule. At this time, the upper edges of the wall portions of the screen disk 3 slide over the inclined surface on the circumferential bead 12 and are pushed inward until they pass the narrowest point of the circumferential bead 12 and the screen disk 3 can be pushed out of the lid 2 with little force. Screen disk 3 and snap disk 4 can thus be disassembled and remounted without tools for cleaning.FIG. 2 shows a preferred exemplary embodiment of the "shaping" solution as a section of a side view. For a better understanding, only the cut surface of the screen disk is shown. The dashed line shows the position of the snap disc and the disc with a protrusion when the valve opening is open.The construction is substantially identical to the exemplary embodiment in FIG. 1 a. However, one difference lies in the fact that a disk with a formation 7 is arranged between the snap disk 4 and the screen disk 3. The disk with a formation 7 is designed as an elastically deformable disk made of stainless spring steel, namely with several holes in order to allow coffee beverage to pass from the screen disk 3 to the valve opening 6, a formation as a truncated cone in the region of the contact surface with the valve opening 6 of the snap disk 4 and a spherical cap as a termination, which can strike against a surface of the capsule coffee machine with a formation 7 outwards when the disk is elastically deformed. The necessary elastic deformability is achieved by the relatively thin wall thickness of 0.2-0.3 mm. The screen disk 3 is thus substantially designed as described in the exemplary embodiment according to FIG. 1 a. However, the difference is that it does not have a valve pin.FIG. 3 ashows a preferred embodiment of the "shaping" solution as a section of a side view, wherein FIG. 3 bshows a view in the direction of the axis of rotation of the valve pin in the disk with a shaping. For a better understanding, only the cut surface of the screen disk is shown. The dashed line shows the position of the snap disc and the disc with a protrusion when the valve opening is open.The construction is substantially identical to that of the embodiment shown in FIG. 2, however, a difference lies in that the screen disk 3 has a hole in the center, which hole has the shape of two semicircles, the ends of which are connected to straight lines, respectively. A further difference lies in the fact that the shaping of the pane with a shaping 7 does not have a spherical cap as a termination, but rather a planar surface. A pin 17 is fastened to the latter by means of a spot weld, which has a cylindrical cross section in the central part and at its head a cross section which corresponds to the hole in the screen disc 3, but which is reduced by slightly more than the manufacturing tolerances of the two parts in order to always be able to pass freely through it. The pin 17 can be inserted with its head through the hole in the screen disc 3 in an orientation. After a rotation of a few degrees, preferably 30°-90°, the head can no longer be guided through the hole. The cylindrical part of the pin 17 can then, however, still be moved freely up and down in the hole when a disc with a formation 7 and the screen disc 3 are inserted into the cover 2 in this position relative to each other. The screen disk 3 thus serves as a stop for the disk with a formation 7 and limits the deformation or the path of the disk with a formation 7 outwards when the snap disk 4 is pressed outwards during the brewing process by the pressure in the capsule.FIG. 4 shows a preferred exemplary embodiment of the solution "snap disc without hole" as a section of a side view of a capsule. For a better understanding, only the cut surface of the screen disk is shown. The dashed line shows the position of the bimetallic snap disc when the valve opening is open.The construction is substantially identical to the exemplary embodiment in FIG. 1 a except for the following differences: instead of a snap disc, a round disc with an outlet opening 9 rests on the circumferential step 13 on the cover 2. It has a concentric, circumferential bead which projects into the interior of the capsule and on which the screen disc 3 rests. The bead simultaneously serves as a lateral guide for the bimetallic snap disc 4, for which purpose the distance from the bead must be so large, even with the greatest manufacturing tolerances, that the edge of the bimetallic snap disc 4 can move freely up and down during snapping over.The disc with outlet opening 9 has a further, somewhat smaller concentric, circumferential bead which projects into the interior of the capsule and against which the bimetallic snap disc 4 is pressed. Within this bead there is an outlet opening 6 with an edge which is corrugated up and down in a wave-shaped manner so that coffee beverage can flow between bimetallic snap disc 4 and disc with outlet opening 9 to outlet opening 6 when bimetallic snap disc 4 is snapped over and then no longer rests on the somewhat smaller bead, but rather on the edge of outlet opening 6.The screen disk 3 is substantially designed as described in the exemplary embodiment in FIG. 1 a. One difference is that it does not have a valve pin, but at least three formations towards the bimetallic snap disc 4 on which it can bear when it is snapped over so that coffee beverage can pass through the gap between the formations. A further difference lies in the fact that it has in the middle a formation in the direction of the bimetallic snap disc 4 which presses the latter, in the non-snapped-over state, against the smaller concentric, circumferential bead in the disc with outlet opening 9.The opening behavior of this embodiment is such that the bimetallic snap disc 4 snaps over as soon as the opening pressure and thus the snap-over force of the bimetallic snap disc 4 is reached in the interior of the capsule during the brewing process, and the bimetallic snap disc 4 releases the valve opening 6 as soon as it has been snapped over beyond the snap-over point and then no longer bears against the smaller concentric circumferential bead. It snaps back as soon as the snap-back temperature is reached again on cooling.List of reference characters1 Container 2 Cover 3 Screen disk 4 Snap disk 5 Valve pin 6 Valve opening 7 Disk with a formation 8 Formation 9 Disk with outlet opening 10 Seal on cover 11 Groove on cover 12 Bead on cover 13 Step on cover 14 Flange on cover 15 Openings in screen disk 16 Inlet openings 17 Pin

Claims

Capsule for containing coffee powder and for producing a coffee beverage with the aid of water in a device containing the capsule, wherein the capsule comprises a container (1) having an interior space accessible via an opening and a lid (2) for reversibly opening and closing the opening by a user, characterized in that a snap disc (4) is arranged on the container (1) and / or on the lid (2), which snap disc can also be a bimetallic snap disc, wherein the snap disc has a curvature which extends over the entire disc or only a part, wherein the curvature snaps over by applying a force to the curvature after reaching the snap-over force and thereafter remains snapped over by applying a force smaller than the snap-over force, until the snap-back force is undershot and the curvature snaps back into the starting shape, wherein the snap-back into the starting shape in the case of a bimetallic snap disc takes place only when a snap-back temperature is undershot, wherein the snap disc is designed such that it is in a non-snapped state below a predetermined pressure in the capsule and in a snapped state starting from the predetermined pressure in the capsule, and the snap disc (4) is designed and arranged such that, in the non-snapped state, it seals off the interior of the capsule from the outside and, in the snapped-over state, it opens off an opening from the outside, which allows coffee beverage to escape from the interior of the capsule from the outside.Capsule according to claim 1, wherein the snap disc (4) has at least one valve opening (6) which is closed by a closure element in the non-snapped-over state of the snap disc (4) and which is open in the snapped-over state of the snap disc (4).Capsule according to claim 2, wherein the closure element has a region, the cross section of which corresponds to the shape of the valve opening (6) in the snap disc and which, in the non-snapped-over state, is seated sealingly in the valve opening (6), wherein the closure element is designed and arranged such that, when the snap disc (4) is snapped over from the non-snapped-over state to the snapped-over state, it does not move with the latter, but rather remains in its position such that the valve opening (6) is opened.Capsule according to claim 2, wherein the closure element is pressed against the valve opening (6) by a resilient element and the closure element moves with the snap disc (4) from the non-snap-over state to the snap-over state when it snaps over, but is stopped by a stop after the snap disc (4) has passed the snap-over point, and the closure element then no longer closes the valve opening (6).Capsule according to claim 3, wherein the closure element has a first region which corresponds in shape and size to the valve opening (6), and a second region which adjoins the first region and tapers in the direction in which the snap disc (4) snaps over.Capsule according to claim 1, wherein the snap disc (4) is formed and arranged such that in the non-snapped-over state it presses with its circumferential edge against a contact surface in the interior of the capsule in order to seal the interior of the capsule and in the snapped-over state is at a distance from the contact surface, wherein the contact surface forms a closed circumferential line, within which at least one opening is located in the capsule, through which coffee beverage can escape from the interior of the capsule outwards in the snapped-over state of the snap disc (4).Capsule according to one of the preceding claims, wherein the snap disc (4) is designed as a bimetallic snap disc.Capsule according to any one of the preceding claims, wherein the snap disc (4) is preceded towards the interior by a screen disc (3) provided with openings (15) designed to retain coffee powder but to pass coffee beverage.Capsule according to claim 4, 6 or 7, wherein an elastomer is applied partially or completely to the side of the snap disc (4) which bears against the closure element or against the contact surface in the interior of the capsule.Capsule according to one of the preceding claims, wherein the snap disc (4) has radially or concentrically impressed ribs.

Images