Coffee capsule

Abstract

A capsule which under pressure in expresso machines is suitable for extraction of coffee, including a truncated cone-shaped capsule body of thermoformed plastic having a conical side wall, the wider end of the side wall defining an outlet side of the capsule and the narrower end of the side wall defining an inlet side of the capsule. A destructible inlet sealing membrane closes the inlet opening of the capsule body and is attached to the inside of the capsule body. The capsule body further includes a circumferential centering ramp at the narrower end of the conical side wall, which translates into an inwardly directed circumferential second flange forming the circular inlet opening, the circumferential centering ramp designed to align the inlet sealing membrane with the inlet opening before welding it to the second flange. The inlet sealing membrane has a diameter larger than the outer diameter of the second flange to be bend upwards along the centering ramp and to at least partially cover the centering ramp when welding it to the second flange. The upwards bend edge forms a heat protecting layer between a hot sealing tool and the centering ramp during welding.

Claims

1. A capsule which under pressure in espresso machines is suitable for extraction of coffee, the capsule comprising: a truncated cone-shaped capsule body of thermoformed plastic having; a conical side wall, the wider end of the side wall defining an outlet side of the capsule and the narrower end of the side wall defining an inlet side of the capsule; an outwardly directed circumferential first flange on the wider end of the conical side wall providing a sealing area towards a brewing chamber of the espresso machine; and a circular inlet opening on the narrower end of the conical side wall; the capsule further comprising; a destructible outlet sealing membrane being attached to the first flange and closing the outlet side of the capsule body; and a destructible inlet sealing membrane closing the inlet opening of the capsule body and being attached to the inside of the capsule body; wherein the capsule body further comprises a circumferential centering ramp at the narrower end of the conical side wall, which translates into an inwardly directed circumferential second flange forming the circular inlet opening, the circumferential centering ramp designed to align the inlet sealing membrane with the inlet opening before welding it to the second flange; and wherein the inlet sealing membrane has a diameter larger than the outer diameter of the second flange, such that the circular edge of the inlet sealing membrane is able to bend upwards along the centering ramp and at least partially covers the centering ramp when welding it to the second flange, wherein the upwards bend circular edge forms a heat protecting layer between a hot sealing tool and the centering ramp during welding the inlet membrane to the second flange.

2. The capsule of claim 1, wherein the circumferential centering ramp has an off-axis angle to the longitudinal axis of the capsule of 20 to 50 degrees.

3. The capsule of claim 1, wherein the second flange is approximately perpendicular to the longitudinal axis of the conical side wall and forms a bottom portion of the capsule body.

4. The capsule of claim 1, wherein the second flange has a width in radial direction of 2 to 3 mm.

5. The capsule of claim 1, wherein the diameter of inlet sealing membrane is 5 to 15% larger than the outer diameter of the second flange, such that it partially covers partially covers the centering ramp when attached to the second flange.

6. The capsule of claim 1, wherein the second flange and the inlet sealing membrane form a flat bottom portion of the capsule.

7. The capsule of claim 1, wherein the capsule body is thermoformed from a layered plastic sheet material comprising on both outer sides a layer of polypropylene and an inner barrier layer of EVOH.

8. The capsule of claim 1, wherein the sealing membrane is a metallic membrane.

9. The capsule of claim 8, wherein the outlet and inlet sealing membrane are coated on the sealing side with polypropylene to improve welding onto the first or second flange, respectively.

10. The capsule of claim 1, wherein the inlet membrane is permanently attached to the second flange by welding.

11. The capsule of claim 1, wherein the inlet and/or outlet sealing membrane are structured by embossing.

12. The capsule of claim 1, wherein the circumferential centering ramp has an off-axis angle to the longitudinal axis of the capsule of 35 to 40 degrees.

13. The capsule of claim 1, wherein the second flange has a width in radial direction of between 2.2 and 2.5 mm.

14. The capsule of claim 1, wherein the diameter of inlet sealing membrane is about 10% larger than the outer diameter of the second flange, such that it partially covers partially covers the centering ramp when attached to the second flange.

15. The capsule of claim 1, wherein the sealing membrane is an aluminium membrane.

16. The capsule of claim 15, wherein the outlet and inlet sealing membrane are coated on the sealing side with polypropylene to improve welding onto the first or second flange, respectively.

Description

BRIEF EXPLANATION OF THE FIGURES

(1) The invention is described in greater detail below with reference to embodiments that are illustrated in the figures. The figures show:

(2) FIG. 1 a perspective view of the capsule showing the inlet side;

(3) FIG. 2 a sectional view of the capsule of FIG. 1;

(4) FIG. 3 a detailed view of the capsule of FIG. 1; and

(5) FIG. 4 a detailed view of the capsule during welding.

EMBODIMENTS OF THE INVENTION

(6) FIG. 1 and FIG. 2 show a perspective view and a sectional view of the capsule according to the invention. The capsule 1, which may be filled with roasted and ground coffee (not shown), has a truncated cone-shaped capsule body 2 made of thermoformed plastic. The capsule body 2 has a conical side wall 3 the wider end of which defines an outlet side 4 of the capsule 1 and the narrower side of which defines an inlet side 5 of the capsule 1. The inlet side 5 of the capsule 1 refers to the water entering side of the capsule in use, where hot injection means of a expresso machine penetrate into the capsule. The outlet side 4 of the capsule 1 refers to the side, where the brewed coffee leaves the capsule 1.

(7) The capsule body 2 comprises on its wider end an outwardly directed (away from the longitudinal axis A of the capsule body) circumferential first flange 6 provided with a sealing and clamping area 7 to seal the capsule 1 against a brewing chamber of a expresso machine and hold the capsule in said brewing chamber in position while the coffee is brewed. A destructible outlet sealing membrane or film 8 of aluminium is welded from the outside onto the first flange 6.

(8) The capsule body 2 is further provided with an inwardly directed (towards the longitudinal axis A of the capsule body) circumferential second flange 9 on the narrower inlet side defining an inlet opening 10. The second flange 9 is formed after the thermoforming process by cutting the opening 10 into the bottom of a preformed capsule body. A destructible inlet sealing membrane or film 10 of aluminium is welded from the inside onto the second flange 9 to sealingly close the inlet opening 10. The diameter of the inlet opening 10 is designed such that hot injection needles or piercing members of the expresso machine cannot touch the plastic capsule body 2 while penetrating into the capsule 1, but only pierce the aluminium sealing membrane 10.

(9) The second flange 9 is approximately perpendicular to the longitudinal axis A of the conical side wall 3 forming a bottom portion of the capsule body 2. The width in radial direction of the second flange is 2 to 3 mm, preferably between 2.2 and 2.5 mm, most preferably approximately 2.4 mm, to allow enough contact area for welding the inlet sealing membrane 11 onto the capsule body 2.

(10) Between the second flange 9 and the conical side wall 3, the capsule body 2 further comprises a circumferential centering ramp 12 with an off-axis angle to the longitudinal axis A of 20 to 50 degrees, preferably about 35 to 40 degrees, as can be nicely seen in the detailed views of FIG. 3 and FIG. 4.

(11) The centering ramp 12 fulfils two functions: firstly it supports the precise alignment of the inlet sealing membrane 11 with the second flange 9 and the inlet opening 10 when placed inside the capsule body 2 during the manufacturing process of the capsule 1; secondly it supports protection of the conical side wall 3 from the heat of the sealing tool e.g. in form of a welding iron 14 (see FIG. 4) during the thermo welding. Therefore, the circular inlet sealing membrane 10 has a diameter slightly larger as the outer diameter of the second flange 9 (or the corresponding inner diameter of the centering ramp 12), preferably larger by about 5 to 15%, more preferably by about 10%. The oversize together with the inclined centering ramp 13 leads to an upwards bend 14 of the circular edge of the inlet sealing membrane to form a heat protecting layer between a hot sealing tool 14 and the plastic capsule body 2 during welding (see FIG. 4).

(12) Both the outlet and inlet sealing membrane (8, 11) are provided with a coating, preferably polypropylene, in order to effectively weld it onto the respective flange (6, 9). The sealing membranes (8, 11) of aluminium may further have an embossed structure to reduce unintentional tearing of the membrane.

REFERENCE SIGNS

(13) 1 capsule 2 capsule body 3 conical side wall 4 outlet side 5 inlet side 6 first flange 7 sealing area 8 outlet sealing membrane 9 second flange 10 inlet opening 11 inlet sealing membrane 12 centering ramp 13 bend in inlet sealing membrane 14 sealing tool/welding iron