Liquid seal rubber applied to a capsule

Abstract

A method provides a rubber-elastic sealing member onto a capsule intended for producing a beverage in a beverage production device. The capsule has a body portion having a side wall and a flange-like rim portion. The rim portion extends from the side wall of the body portion. The method includes the steps of applying an uncured sealing composition in a liquid or viscous state onto the rim portion of the capsule, heating said applied sealing composition such that the sealing composition at least partially migrates towards the side wall until the sealing composition reaches the side wall, and curing the sealing composition after the migration towards the side wall.

Claims

1. A capsule for containing beverage ingredients which is designed for insertion in a beverage production device in which a liquid under pressure enters the capsule in order to interact with the beverage ingredients in the capsule and to drain a beverage from the capsule, the capsule comprising: a body; a rim that is a flange; and a resilient sealing member formed on an outer surface of the capsule, the resilient sealing member forms a continuous portion distributed about a circumferential transition from the rim to a side wall of the capsule, an outer surface of the resilient sealing member is concave when viewed in a cross-sectional view, the outer surface continuously curving inward toward the circumferential transition of the capsule, the resilient sealing member has a maximum thickness, when measure at an angle of 45 degrees from the flange of the rim toward the side wall, of between 0.3 and 0.7 mm, and the thickness of the resilient sealing member continuously decreases towards a first end at the side wall of the capsule and a second end at the rim, respectively.

2. The capsule according to claim 1, wherein the resilient sealing member has a mass of between 10 and 150 mg and a hardness of between 20 and 40 Shore A.

3. A beverage production system, comprising (i) a capsule for containing beverage ingredients and (ii) a beverage production device, the beverage production device having an enclosing member adapted to be in selective sealing engagement with a sealing member of the capsule; the beverage production device comprises an opener configured to produce at least one opening in a first and a second wall members of the capsule; the at least one opening in the first wall member is separated from the at least one opening in the second wall member by a pressure-tight sealing engagement of a pressing surface of the beverage production device and the sealing member of the capsule, such that liquid can only flow through the capsule, but not at an exterior of the capsule; and an outer surface of the sealing member is concave when viewed in a cross-sectional view, the outer surface continuously curving inward toward the circumferential transition of the capsule, the resilient sealing member has a maximum thickness, when measure at an angle of 45 degrees from the flange of the rim toward the side wall, of between 0.3 and 0.7 mm, and the thickness of the resilient sealing member continuously decreases towards a first end at the side wall of the capsule and a second end at the rim, respectively.

4. The capsule according to claim 1, wherein the outer surface of the resilient sealing member curves inward toward the circumferential transition from the rim to the side wall of the capsule.

5. The beverage production system according to claim 3, wherein the outer surface of the sealing member curves inward toward the circumferential transition from the rim to the side wall of the capsule.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features, advantages and objects of the present invention will become apparent for the skilled person when reading the following detailed description of embodiments of the present invention, when taken in conjunction with the figures of the enclosed drawings.

(2) FIG. 1 shows an extraction capsule known from prior art document EP-A-512 470.

(3) FIG. 2 shows a body of the capsule according to the present invention in sectional side view.

(4) FIG. 3 shows an enlarged view of area Z indicated in FIG. 2.

(5) FIGS. 4a to 4c show the application of the sealing composition onto the rim portion of the capsule's body.

(6) FIGS. 5a to 5c show the applied sealing composition after the heating step and the curing step.

(7) FIG. 6 shows a preferred embodiment of the beverage production device comprising an enclosing member suitable for enclosing a capsule according to the present invention in order to enable a beverage preparation.

(8) FIG. 7 shows the interaction of the sealing composition applied to the intersection between the rim portion and the body portion of the capsule and a dedicated enclosing member of a beverage production machine.

DETAILED DESCRIPTION

(9) FIG. 2 shows a preferred embodiment of a capsule according to the present invention in sectional side view. The capsule 1 comprises a frusto-conical body portion 3 having a side wall 3a and a substantially transversal closed base portion 3b. Said base portion 3b comprises a central recess 3c. At the other end of the frusto-conical body portion 3, a flange-like rim portion 2 is connected to the side wall 3a of the capsule. Thereby, the flange-like rim portion 2 is preferably orientated perpendicular to the central axis c of the capsule 1.

(10) The capsule 1 is preferably an integral part made of metal such as aluminum. Thereby, the shown embodiment of the capsule 1 in FIG. 2 is preferably obtained by a deep drawing operation.

(11) The capsule 1 has an outer surface 7a and an inner surface 7b.

(12) At the intersection of the side wall 3a of the body portion 3 and the flange-like rim portion 2 sealing means 4 are applied which are preferably of a linear or meniscus-like form when seen in cross sectional view.

(13) The indicated height h of the capsule is preferably between 10 and 30 mm. The indicated diameter d1 of the side of the body 3 of the capsule 1 to which the flange-like rim portion 2 is connected, is preferably between 20 and 50 mm. Moreover, the indicated diameter d2 of a second side of the body portion 3 of the capsule 1 which comprises the recess 3c is preferably between 20 and 30 mm.

(14) FIG. 3 is an enlarged view of area Z indicated in FIG. 2 which relates to a sectional side view of the transition 8 between the body portion 3 and the rim portion 2 of the capsule.

(15) The rim portion 2 comprises an upper surface 13a being arranged adjacent to the surface 7a of the side wall 3a and a lower surface 13b being adjacent to the inner surface 7b of the side wall 3a of the capsule body portion 3.

(16) As can be seen in FIG. 3, the rim portion 2 and the side wall 3a preferably intersect by means of a transition 19 which is preferably curved such that no sharp edge is formed between the rim portion 2 and the body portion 3. Thereby, the intersection 19 preferably comprises a radius of curvature between r=0.2 cm to r=0.8 cm.

(17) Furthermore, as indicated in FIG. 3, the rim portion 2 is oriented at a certain angle a to the side wall 3a of the body portion 3 which is preferably equal to or slightly higher or smaller than 90.

(18) At the end portion 9 of the flange-like rim portion 2 a curled end is preferably formed and hence, no sharp edges are protruding from the capsule at the flange portion 2. Accordingly, a user is prevented from cutting himself when handling the capsule 1.

(19) The thickness t1 of the side wall 3a is preferably equal to the thickness of the rim portion 2. Thereby, the thickness t1 is preferably between 0.1 and 0.5 mm.

(20) The sealing means 4 provided at the transition 19 between the rim portion 2 and the side wall 3a of the body portion 3 are preferably of L-shaped form when seen in cross-sectional side view.

(21) Reference number a denotes an axis which is arranged at a 45 angle to the rim portion 2 and which intersects the indicated intersection point 8 of the rim portion 2 and the side wall 3a of the capsule 1. Thereby, the sealing means 4 have their maximum thickness t2 which is preferably between 0.3 and 0.7 mm, and more preferably between 0.4 mm and 0.6 mm in the direction of the indicated axis a. Accordingly, a maximum thickness t2 of the sealing means 4 is provided at the transition 19 between the rim portion 2 and the side wall 3a of the body portion 3. Hence, enclosing means of a dedicated beverage production device may effectively interact with the capsule 1 in order to enable effective sealing of the capsule 1 during a beverage production process.

(22) Furthermore, the thickness t2 of the sealing means 4 continuously decreases towards the end 9 of the rim portion 2 and towards the indicated end 15 of the sealing means 4 at the side wall 3a of the body portion 3 as indicated by reference numerals t2 and t2 in FIG. 3. According to this embodiment, a concave L-shaped form of the sealing means 4 is obtained.

(23) The sealing means 4 are preferably applied between the side wall 3a of the capsule 1 and the end 9 of the rim portion 2, i.e. the sealing means 4 comprise an outer diameter d4 which is preferably between 30 and 40 mm. The inner diameter of the capsule 1 is indicated by reference number d3 and is preferably between 25 and 35 mm.

(24) With reference to FIGS. 4a to 4c, the application process of the sealing composition 4 to the rim portion 2 of the capsule 1 will be described in the following.

(25) As can be seen in FIG. 4a, an uncured and thus, a liquid or viscous sealing composition 4 is dispensed onto the upper surface 13a of the flange-like rim portion 2. Thereby, the liquid or viscous sealing composition 4 is dispensed by means of a dispensing needle or nozzle member 11 which is connected to a sealing composition supply 12. Moreover, a pump 13 is provided between the supply 12 and the nozzle member 11 and thus, a predefined pressure can be provided to the nozzle member 11 in order to enable a dispensing of the liquid sealing composition 4. In addition, a control unit 14 may be provided which is at least connected to the pump 13 and thus, enables the adjustment of the applied pressure.

(26) The sealing composition 4 is preferably selected from elastomers, silicones, plastics, latex, balata or others. More preferably, as sealing composition a heat-curing silicon adhesive is used which has the advantages of bonding to many substrates without a primer and which occurs rapidly at elevated temperatures. A preferred silicone-rubber sealing composition. In particular, a one-component curing silicone system is preferred such as Addisil 1540 D. Such system is sensitive to temperature and must be kept at chilled temperature (5-8 C.) before depositing. It should also be applied at a controlled atmosphere at ambient temperature in order to control its viscosity during deposition so that the dosing is accurate and blocking problems of the dosing means are avoided.

(27) The supply means 12 may be a tamper seal barrel. The material is preferably kept in chilled conditions before deposition onto the capsule 1 to ensure that no curing has started which would affect the viscosity of the material and so the dispensing and forming capabilities on the capsule 1. Before the dispensing process, the lid of the barrel may be removed and replaced by a piston. Therefore, the barrel may serve as a cylinder for delivery of the liquid rubber. By means of the described control means 14 and the piston pump 13, the dispensing time and the dispensing pressure may be adjusted for the dispensing process.

(28) Preferably, the control unit 14 adjusts the applied pressure of the pump 13 such that pulsing occurs at the beginning of the dispensing process. Accordingly the so-called snake-head effect can be prevented and thus, no (or at least a reduced amount of) sealing composition accumulates at the tip portion 11a of the needle or nozzle element 11.

(29) The liquid sealing composition 4 is preferably dispensed at a predefined distance d to the transition 19 of the side wall 3a and the rim portion 2. Thereby, the sealing composition 4 is preferably dispensed onto a central portion 5 of the rim portion 2 as indicated in FIG. 4a. Accordingly, enough space for the nozzle or needle member 11 to approach the rim portion 2 during the dispensing process is provided.

(30) Preferably, the distance d is chosen to be between 0.5 and 3 mm. It should be noted that the sealing composition 4 should not be dispensed too far away from the side wall 3a of the body portion 3 of the capsule 1, since this would result in an insufficient sealing and thus, leakage may appear during the beverage production process. In particular, the position is also critical because of the very thin seal which is applied onto the capsule 1.

(31) FIG. 4b shows a top view of the capsule 1 after the dispensing of the sealing composition 4 to the rim-portion 2. As can be seen in FIG. 4b, a cord 15 is dispensed in a circumferential way to the body 3 of the capsule 1 onto the upper surface 13a of the flange-like rim portion 2. Thereby, the dispensing process is preferably non continuous, i.e. a gap 16 is formed between the dispensing start point 15a and the end point 15b of the dispensing process. Accordingly, the flowing of the rubber material before curing is anticipated. The distance of the gap may, for instance be of from 0.5 to 3 mm.

(32) The time for the dispensing process of the liquid or viscous rubber sealing material is preferably between 400 and 900 ms. As the amount of deposited sealing material is preferably small, i.e., preferably between 40 and 80 mg, the dispensing means which comprises at least the nozzle member 11, the pump 13, the control means 14 and the supply means 12 are preferably designed such that a precision of +/3 mg is achieved. Hence, a very accurate dispensing of the sealing component 4 is obtained.

(33) The gap 16 between the dispensing start and end point 15a,15b of the sealing composition cord 15 is preferably between 0.1 and 0.5 mm. It should be noted that more than one gap 16 may be formed at the cord 15 during the dispensing process. For example, the cord 15 may be applied to the rim portion 2 in an intermittent way.

(34) As can be seen in FIG. 4b, the sealing composition cord 15 applied to the rim portion 2 is circumferentially arranged to the body 3 of the capsule 1 and is preferably concentric to central axis c of the capsule 1. Thereby, the cord 15 is of a unitary width t3 which is preferably between 1 and 2 mm.

(35) FIG. 4c relates to a sectional side view of the rim portion 2 (A-A indicated in FIG. 4b) after the application of the sealing composition 4. As can be seen in FIG. 4c, the liquid or viscous sealing composition 4 is situated at a fixed distance d to the transition 19 of the rim portion 2 and the side wall 3a.

(36) FIGS. 5a to 5c relate to a preferred embodiment of the applied sealing composition after the heating and the curing step.

(37) FIG. 5a shows the migration process of the sealing composition 4 during heating. Thereby, reference number 4 relates to the sealing composition shown in FIGS. 4b and 4c which has been applied to the rim portion 2 by means of a dispensing process. Now, during heating of the capsule 1, migration of the sealing composition 4 towards the side wall 3a of the body 3 is enforced as indicated by arrow M. Heating of the liquid or viscous sealing composition 4 is preferably carried out at a temperature between 60 and 80 C., more preferably, the heating temperature is set to 70 (+/2) C.

(38) Heating of the sealing component 4 is carried out for 1 to 4 minutes, preferably for 3 minutes.

(39) It should be understood that the flow or migration of the sealing component 4 is due to attractive forces such as electrostatic forces or the surface tension to the side of the body of the capsule. The forces may be influenced by the used material of the capsule. In addition, due to the fact that the capsule body 3 and the rim portion 2 is preferably formed by a deep drawing operation, the capsule 1 may be covered with a lacquer and residue of lubricant which are necessary for the deep drawing operation and which may influence the attraction of the liquid or viscous sealing composition 4. Certain lubricants may be preferred for their affinity with the material of the sealing member such as silicone based lubricants. Other lubricants should be avoided because they might negatively affect cross-linking. For example, ester-base lubricants are not desired.

(40) During migration of the sealing component 4, the provided gap 16 disappears, i.e. the dispensing start point 15a and the end point 15b are joined together, resulting in a continuous sealing portion 4 of accurate and unitary width t4 as shown in FIG. 5b. As the sealing component 4 flow towards the side wall 3a of the body portion 3 of the capsule, there are no gaps present between the side wall 3 and the sealing component 4. The width t4 is preferably between 0.5 and 2 mm.

(41) After the heating process, curing of the sealing component 4 is carried out. The curing is preferably carried out at a temperature between 110 and 160 C., more preferably between 115 to 125 C. Thereby, the sealing component 4 is cured for a predefined time of 4 to 10 minutes. More Preferably, curing is carried out for a time of 6 minutes.

(42) Due to the curing of the sealing composition 4, a cross-linking of the material is obtained after it has flown to the side wall 3a of the body 3.

(43) FIG. 5c relates to a sectional side view (B-B in FIG. 5b) of a preferred embodiment of the sealing composition 4 after the curing process. Due to the curing, the sealing composition 4 may be slightly retracted. However, the general concave L-shaped or meniscus-shaped form of the sealing composition 4 is not affected by the curing process according to the invention.

(44) FIG. 6 shows a state in which a capsule 1 according to the present invention has been placed into a beverage production device. Thereby, the capsule 1 is provided with sealing means 4 according to the invention. Moreover, the interior of capsule 1 has been filled with portioned ingredients 21 and the capsule 1 has been sealed by means of a foil member 25. Thereby, the foil member 25 is sealed to the flange-like rim portion 2 to close-off hermetically the body portion 3 of the capsule 1.

(45) The ingredients 21 within the capsule 1 are selected such that a beverage can be produced when having a liquid entering the capsule in the region of the recess 3c of the capsule 1 and then interact which such ingredients 3. Preferred ingredients are e.g. ground coffee, tea or any other ingredients from which a beverage or other liquid or viscous comestible (e.g. soup) can be produced.

(46) Note that the foil member 25 as shown is not exactly flat due to a defined over pressure inside the capsule, which over pressure is generated by natural degassing of the ground coffee in the capsule and eventually further introducing e.g. a protective gas when producing the filled capsule 1.

(47) A capsule holder 20 of the beverage production device is preferably equipped with relief elements 22 which are designed to tear and perforate the foil member 25 of the capsule 1. This tearing of the foil member can e.g. occur as soon as the pressure inside the capsule exceeds a threshold value. Note that the relief elements 22 can have any protruding shape able to cause a (partial) tearing of the foil member. As an example only pyramids, needles, bumps, cylinders, elongated ribs are cited.

(48) As shown in FIG. 6, the capsule 1 is placed on a capsule holder 20 of the beverage production device, the foil member 25 resting on the relief element 22 side of the capsule holder 20 and the base body 3 of the capsule 1 being already partly surrounded by the circumferential wall 24 of an enclosing member 23 of the beverage production device. The shown enclosing member 23 has the shape of a bell. However, other shapes are viable, wherein the design of the interior contours (recess) of the enclosing member 23 is generally adapted to substantially match the contours of the capsule 1.

(49) The enclosing member 23 may comprise an external thread 26 for mounting the enclosing member in a beverage production device and a water inlet opening 27 for feeding a liquid such as for example hot water under pressure to a water injector 28 which is releasable mounted (screwed) to the enclosing member 23.

(50) It should be noted that the shown thread 26 is just an example for connection means and therefore, any other releasable or permanent connection means may be used to connect the enclosing member 23 to a beverage production device.

(51) The other components of the beverage production device, such as e.g. the mechanism for displacing the enclosing member 23 and eventually also the capsule holder 20 are known from the prior art in the field of capsule-based espresso machines.

(52) The water injector 28 may be equipped with a needle or nozzle element (not shown) to pierce water inlets in the body of the capsule 1.

(53) Moreover, the water injector 28 preferably comprises opening means 29 for opening a face of the capsule 1. Such opening means 29 may for example be a perforation element such as a blade, pin, etc. designed to produce an opening in the recess 3c or the top wall 3b of the capsule 1 when the capsule holder 20 and the enclosing member 23 are moved close together e.g. by a manually operated or a automatic mechanism. According to this, a liquid such as water can be fed to the interior of the capsule 1 once the perforation element 29 protrudes into the interior of the capsule 1.

(54) Preferably, the enclosing member 23 is equipped with release means 30 for releasing the capsule 1 after the injection of liquid thereto. Said release means 30 prevent a vacuum effect when the capsule 1 is to be released after it has been enclosed by the enclosing member 23 and the capsule holder 20. Accordingly, when the capsule holder 20 is opened, the risk that the capsule 1, instead of falling down, remains sucked into the enclosing member 23 due to a vacuum effect can be avoided. Preferably, said release means 30 are apertures or recessed provided at the circumference of the lower edge 23a of the enclosing member 23 such that air can get into the space between the top wall 3b and the side walls 3a of the capsule 1 and the inner wall 23b of the enclosing member 23, respectively.

(55) FIG. 7 relates to the interaction of the sealing means 4 applied to the intersection between the rim portion 2 and the body portion 3a of the capsule 1 and the enclosing member 23 of a beverage production device.

(56) As can be seen in FIG. 7, the cured sealing composition 4 which has been provided to the capsule 1 is compressible. Accordingly, when the enclosing member 23 and the capsule holder 20 (see FIG. 6) are brought into a position to enclose the capsule 1, a lower edge 23a of the enclosing member 23 is pressed against the sealing means 4 and thus, against the rim portion 2. Thereby, the transition portion 23c of the lower edge 23a and the inner wall 23b of the enclosing member 23 is preferably round-shaped as indicated in FIG. 7. However, the transition portion 23c may as well be chamfered.

(57) The lower edge 23a is preferably equipped with radial grooves or recesses 30 as already described in order to prevent a vacuum effect when the capsule 1 is to be released from the enclosing means 23 and the capsule holder 20.

(58) Furthermore, the enclosing member 23 comprises an annular skirt 31 and a circular recess 23d for promoting the evacuation of water through the nip when no capsule is inserted in the device as described in co-pending patent application Ser. No. 08/153,050.3 entitled: Beverage production device for producing a beverage from a single-use capsule.

(59) If water is injected to the capsule 1 by means of the injector 28 (see FIG. 6), pressurized liquid may be present between an inner wall 23b of the enclosing member 23 and the side wall 3a of the capsule 1 as indicated by arrow P (see FIG. 7). Due to the interaction of the lower edge 23a with the sealing means 4 provided to the capsule 1, said pressurized liquid is however prevented from by-passing the capsule 1. Accordingly, effective sealing of the capsule 1 during the beverage production process is obtained.

(60) It should be noted that the radial grooves or recesses 30 provided at the lower edge 23a of the enclosing member 23 are designed such that they are fully covered and/or filled by the sealing means 4 in a closed position of the enclosing means 23 with respect to the capsule holder 20. Thereby, due to the concave L-shaped form of the sealing means 4, said radial grooves or recesses 30 can be effectively covered, including at the interior side of the enclosing means 23, and thus, effective sealing is obtained. Accordingly, no liquid may by-pass the capsule through said grooves or recesses 30.

(61) During the shown closing pressure engagement of the enclosing member 23, the cup holder 20 and the capsule 1, water entering the interior of the capsule 1 by means of a opened wall or face 3c,3b of the capsule 1 builds up pressure inside the capsule. Moreover, due to the pressure rise in the interior of the capsule, the relief members 22 produce openings in the foil member 25 of the capsule 1. Accordingly, when a sufficient pressure of water has been built up inside the capsule 1, the beverage produced due to an interaction between the injected water and the portioned ingredients housed within the capsule can be drained in small interstices between the relief members 22 and the surrounding foil member 25. Thereby, due to the sealing means 4 liquid provided to the capsule 1 can only flow through the capsule, but not at the exterior of the capsule.

(62) Although the present invention has been described with reference to preferred embodiments thereof, many modifications and alternations may be made by a person having ordinary skill in the art without departing from the scope of this invention which is defined by the appended claims.

(63) For example, the invention is explained referring to a certain design of a capsule, i.e. a design according to which the capsule comprises a cylindrical or frusto-conical base body and a closing foil member. However, it is to be understood than other designs of the capsule are viable, such as e.g. capsules having a lenticular form with two essentially matching and opposing walls (e.g. foils) being sealed at the e.g. ring-shaped edge. Generally a capsule according to the present invention comprises at least two opposing wall members which are connected to each other at the edges to form a sealed flange-like rim area, thus enclosing a sealed interior.

(64) In order to further improve the production process of the applied sealing composition, after curing of the sealing composition, a quality control process may be carried out to check if the seal has been applied correctly and if the geometry is correct. The control is preferably done by means such as by a vision system or by X-ray. Such a vision system may be equipped with a dedicated camera, e.g. a Cognex camera which produces many flashes of blue/red lights, wherein the reflected lights are analysed and treated by a dedicated suitable software. Furthermore, means for providing X-rays to the sealing may be used for detecting any defects of the sealing.