Method and apparatus for making capsules provided with filter

Abstract

A method for making a capsule provided with a body containing a filtering element suitable for receiving a product for preparing a beverage, including: supplying a first film of thermoplastic material and a second film of filtering material to a forming mold according to a supplying direction, superimposing the second film on the first film, the forming mold including a lower half mold in which a plurality of cavities is obtained and an upper half mold provided with a plurality of stretching elements, one for each cavity, which are movable in one direction that is perpendicular to the supplying direction; pre-heating to a softening temperature the first film of thermoplastic material, by a pre-heating device arranged upstream of the forming mold; closing the forming mold bringing the lower half mold and the upper half mold towards one another until they clamp between one another the first film of thermoplastic material and the second film of filtering material; simultaneously forming in the cavities the bodies of the capsules and the respective filtering elements, using the stretching elements. An apparatus for making a capsule provided with a body containing a filtering element suitable for receiving a product for preparing a beverage, including: one forming mold including a lower half mold wherein a plurality of cavities is obtained and an upper half mold provided with a plurality of stretching elements, one for each cavity, movable in one direction, a supplying means that is movable in one advancement direction that is perpendicular to the direction, to supply simultaneously to the forming mold and to keep taut a first film of thermoplastic material and a second film of filtering material, a pre-heating device for pre-heating at least the first film of thermoplastic material before it is supplied to the forming mold.

Claims

1. A method for making a capsule provided with a body containing a filtering element suitable for receiving a product for preparing a beverage, including the steps of: supplying a first film of thermoplastic material and a second film of filtering material to a forming mold according to a supplying direction, superimposing said second film on said first film, said forming mold having a lower half mold in which a plurality of cavities is obtained and an upper half mold provided with a plurality of stretching elements, one for each cavity, which are movable in a direction that is perpendicular to said supplying direction; pre-heating to a softening temperature said first film of thermoplastic material, by a pre-heating device arranged upstream of said forming mold; closing said forming mold bringing said lower half mold and said upper half mold towards one another until they clamp between one another said first film of thermoplastic material and said second film of filtering material; simultaneously forming in said cavities the bodies of the capsules and the respective filtering elements, using said stretching elements; and delivering compressed air to said forming mold to separate the first film of thermoplastic material from the second film of filtering material and deform both the thermoplastic material and the filtering material until, in each cavity, they reach the final shape of the respective capsule body and of the filtering element associated therewith.

2. The method according to claim 1, wherein, before closing said forming mold, said stretching elements are moved towards said lower half mold until they come into contact with the second film of filtering material superimposed to the first film of thermoplastic material and partially deform said first film of thermoplastic material and said second film of filtering material.

3. The method according to claim 1, wherein said forming includes advancing said stretching elements inside the cavities of the lower half mold to obtain simultaneously preforming of the bodies of the capsules and of the respective filtering elements.

4. The method according to claim 1, wherein said first film and said second film are advanced in said advancement direction and are kept taut by at least one supplying means located downstream of said mold, with respect to said advancement direction.

5. The method according to claim 1, wherein during said closing said first film and said second film are welded together in preset zones.

6. The method according to claim 1, wherein during, or after, the delivery of compressed air to said forming mold, when the first film of thermoplastic material is separated from the second film of filtering material, the stretching elements perform an extra stroke downwards to increase the depth of the filtering element inside the body of the capsule.

7. The method according to claim 1, wherein said first film of thermoplastic material and said second film of filtering material are both preheated and pressed against one another by said pre-heating device so as to be welded together before being supplied to said forming mold.

8. The method according to claim 7, wherein said compressed air deforms the thermoplastic material and the filtering material welded together, until, in each cavity, they reach the final shape of the respective capsule body and of the filtering element associated therewith.

9. The method according to claim 4, further comprising opening said mold at the end of forming the capsule bodies and the respective filtering elements and extracting from the mold said capsule bodies with the respective filtering elements with the help of said supplying means.

10. The method according to claim 1, wherein said thermoplastic material is a compostable material.

11. An apparatus for making a capsule provided with a body containing a filtering element suitable for receiving a product for preparing a beverage, said apparatus including a forming mold having a lower half mold in which a plurality of cavities is obtained and an upper half mold provided with a plurality of stretching elements, one for each cavity, which are movable in a direction, said stretching elements being intended to simultaneously obtain the bodies of the capsules and the filtering elements, and further including: a supplying means that is movable in an advancement direction that is perpendicular to said direction, to supply simultaneously to said forming mold and to keep taut a first film of thermoplastic material and a second film of filtering material, a pre-heating device for pre-heating at least said first film of thermoplastic material before it is supplied to said forming mold, and a conduit through which compressed air can be delivered inside the forming mold; wherein said supplying means includes a gripper element or a catenary element; wherein said second film of filtering material is arranged in such a manner as to be preheated by said preheating device, together with said first film of thermoplastic material; wherein said pre-heating device includes heating plates and wherein said heating plates are arranged so as to exert on said first film of thermoplastic material and on said second film of filtering material, during preheating thereof, a pressure, such that said first film and said second film are welded together.

12. A method for making a capsule provided with a body containing a filtering element suitable for receiving a product for preparing a beverage, including the steps of: supplying a first film of thermoplastic material and a second film of filtering material to a forming mold according to a supplying direction, superimposing said second film on said first film, said forming mold having a lower half mold in which a plurality of cavities is obtained and an upper half mold provided with a plurality of stretching elements, one for each cavity, which are movable in a direction that is perpendicular to said supplying direction; pre-heating to a softening temperature said first film of thermoplastic material, by a pre-heating device arranged upstream of said forming mold; closing said forming mold bringing said lower half mold and said upper half mold towards one another until they clamp between one another said first film of thermoplastic material and said second film of filtering material; and simultaneously forming in said cavities the bodies of the capsules and the respective filtering elements, using said stretching elements; wherein said first film of thermoplastic material and said second film of filtering material are both preheated and pressed against one another by said pre-heating device so as to be welded together before being supplied to said forming mold.

13. The method according to claim 12, wherein said compressed air deforms the thermoplastic material and the filtering material welded together, until, in each cavity, they reach the final shape of the respective capsule body and of the filtering element associated therewith.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) One non limiting embodiment of the method and apparatus according to the invention will be described hereinafter referring to the enclosed drawings, wherein:

(2) FIG. 1 is a schematic view of an apparatus according to the invention;

(3) FIG. 2 is a view as that of FIG. 1 which illustrates a first step of the method according to the invention;

(4) FIG. 3 is a view as that of FIG. 2 which illustrates a second step of the method according to the invention;

(5) FIG. 4 is a view as that of FIG. 3 which illustrates a third step of the method according to the invention;

(6) FIG. 5 is a schematic view which illustrates a fourth step of the method according to the invention;

(7) FIG. 6 is a schematic view which illustrates a variant of the method according to the invention;

(8) FIG. 7 is a view as that of FIG. 1, relative to a further variant of the invention;

(9) FIG. 8 is a view as that of FIG. 1, relative to a still further variant of the invention.

DETAILED DESCRIPTION

(10) In FIG. 1 it is illustrated one forming mold 1 for making beverage capsules provided with a concave-section filtering element 13 (FIG. 4) extending inside a cavity of the body 12 of the capsule for forming a containment chamber of a dose of product for producing a beverage.

(11) The mold 1 comprises a lower half mold 2, wherein a plurality of cavities 3 is obtained intended to form the capsule body, and an upper half mold 4 provided with a plurality of stretching elements 5, for instance punches, one for each cavity 3, movable in one direction indicated by the double arrow F1 and intended to form the body 12 of the capsules and the respective filtering elements 13 by stretching a thermoplastic material and a filtering material respectively, as will be explained in detail hereinafter. In the illustrated example it is shown a mold 1 with two cavities 3. It is understood that there can be any number of cavities 3 in the mold 1.

(12) The mold 1 is supplied with a first film 6 of thermoformable plastic material, which can also be, for example, a compostable plastic material, and with a second film 8 of filtering material, in particular a non-woven tissue, and arranged so as to be superimposed to the strip of thermoformable plastic material.

(13) The first film 6 of thermoformable plastic material can be wound on a first coil 7 and the second film 8 of filtering material may be wound on a second coil 9. Alternatively the first film 6 of thermoformable plastic material and the second film 8 of filtering material may be wound on a same coil.

(14) The first film 6 of thermoformable plastic material and the second film 8 of filtering material are advanced together between the upper half mold 4 and the lower half mold 2 in a direction and in an advancement direction indicated by arrow F2, which is perpendicular to direction F1 along which punches 5 are movable. The transversal dimensions of the first film 6 and of the second film 8, in a direction perpendicular to the advancement direction F2 and to the direction F1, are preferably substantially the same.

(15) Upstream of the mold 1, with respect to the advancement direction F2, a preheating device is arranged comprising a pair of heating elements, including, for example, heating plates, or heating lamps, by means of which the first film 6 is heated up to a softening temperature to allow the subsequent deformation for forming the capsule body.

(16) In the illustrated embodiment, only the first film 6 of thermoformable plastic material is passed through the pair of heating elements 10. Alternatively it is possible to place the second coil 9 upstream of the heating elements 10 so that the second film 8 of filtering material also can pass through the heating elements 10 and can be preheated in order to facilitate the deformation during the forming of the filtering elements 13 (FIG. 7).

(17) If both films are wound on the same coil 16 (FIG. 8), this is arranged upstream of the heating elements 10 so that both films can pass through the heating elements to preheat them.

(18) Downstream of the mold 1, with respect to the advancement direction F2, a gripper element 11 is positioned, or a catenary, movable in both ways in the advancement direction F2, which is used to advance the first film 6 and the second film 8 in the advancement direction F2, and to keep them taut. The gripper element 11, or the catenary, acts as supplying means of the first film 6 and of the second film 8 to the forming mold 1, as while moving in the advancement direction F2 it unwinds the first film 6 and the second film 8 from their respective coils.

(19) If the second film 8 of filtering material has not been preheated, the first film 6 of preheated thermoplastic material heats the second film 8 of filtering material, while the two films are supplied to the mold 1, so as to facilitate the deformation of the second film 8 of filtering material during the forming of the filtering material 13.

(20) In FIG. 1, mold 1 is illustrated in open position, before the starting of the forming of the capsule body and their respective filters.

(21) In FIG. 2 it is illustrated a first step of the forming of the capsule body 12 and of the filtering elements 13, wherein the lower half mold 2 and the upper half mold 4 are brought towards one another and punches 5 are moved towards the lower half mold 2 until they contact the first film 6 of thermoplastic material and the second film 8 of filtering material and partially deform them to realize a first stretching of the first film 6 and of the second film 8, by performing a so called “enrichment” process of the thermoplastic material and of the filtering material, avoiding that during the following stretching or deep drawing operations, required for forming the body 12 of the capsule (FIG. 6) and the filtering element 13 according to desired sizes and volume, the thermoplastic material and the filtering material may tear or wear thin excessively.

(22) In FIG. 3 it is illustrated a second step of the method according to the invention, wherein the mold 1 is closed, clamping the first film 6 and the second film 8 between the lower half mold 2 and the upper half mold 4, and punches 5 are advanced inside the cavities 3 to simultaneously obtain a pre-formation of the bodies 12 of the capsules and of the filtering elements 13.

(23) When the first film 6 of thermoplastic material and the second film 8 of filtering material are clamped between the lower half mold 2 and the upper half mold 4, the thermoplastic material and the filtering material are welded together in preset zones 15, due to the fact that the thermoplastic material, which has been heated by the heating plates 10, is in a softening state, determining, together with the pressure exerted by the two half molds, the welding of the thermoplastic material with the filtering material. It should be noted that in order to guarantee the welding of the thermoplastic material and of the filtering material it is not necessary to heat the two half molds, which allows a significant energy saving.

(24) In FIG. 4 it is illustrated a third step of the method according to the invention, wherein compressed air is injected into the mold 1 through an inlet channel 14 provided, for example, in the upper half mold 4. The inlet of air is indicated with an arrow A, in FIG. 4. Compressed air, passing through the second film 8 of the filtering material separates therefrom the first film 6 of thermoplastic material and deforms both of the thermoplastic material and the filtering material until they assume in each cavity 3 the final shape of the respective capsule body 12 and of the filtering element 13.

(25) During or after the inlet of compressed air into the mold, when the first film 6 of thermoplastic material has separated from the second film 8 of filtering material, an extra stroke downwards of the punches 5 can be provided, to increase the depth of the filtering element 13 inside the body 12 of the capsule.

(26) In FIG. 5 it is illustrated the final step of the forming of the capsule bodies 12 with their respective filtering elements 13, wherein the mold 1 is opened and the formed capsule bodies 12, with the respective filtering elements 13, are extracted out of the mold 1 which is ready for a subsequent forming cycle.

(27) In FIG. 6 it is illustrated a variant of the method according to the invention, wherein the “enrichment” process of the material is omitted. In this variant of the method according to the invention, in a first step, illustrated in FIG. 6, the mold is closed, so as to weld together in preset zones 15 the first film 6 of thermoplastic material and the second film 8 of filtering material. As previously explained, it is not necessary to heat the two half molds to obtain the welding of the thermoplastic material with the filtering material.

(28) Thereafter, in a second step, the punches 5 are advanced inside the cavities 3 to obtain a pre-formation of the bodies 12 of the capsules and of the filtering elements 13, similarly to what is illustrated in FIG. 3.

(29) In a third step, compressed air is introduced into the upper half mold 4, similarly to what is illustrated in FIG. 4, in order to detach the first film 6 of thermoplastic material from the second film 8 of the filtering material and deform both the thermoplastic material and the filtering material until they assume, in each cavity 3, the final shape of the respective capsule body 12 and of the filtering element 13.

(30) Finally, the mold 1 is opened to extract therefrom the formed capsule bodies 12, with the respective filtering elements 13, as already shown in FIG. 5.

(31) The capsule bodies 12 with the respective filtering elements 13, after having been extracted out from the forming mold 1 are sent towards a shearing station (not shown) wherein the capsule bodies 12 are separated from each other by shearing. Shearing may be carried out in zones where the thermoplastic material 6 and the filtering material 8 are welded together, or in zones where the two materials are not welded together. In this latter case it is possible to easily separate the thermoplastic material from the filtering material in the shearing offcuts, facilitating the disposal of offcuts.

(32) Owing to the invention a significant simplification of the process for forming capsule bodies 12 with the respective filtering elements 13 and the forming apparatus is obtained, as the forming of the capsule bodies 12 and of the filtering elements 13 occurs simultaneously in one single mold reducing remarkably the production time and the plant costs, as it is no longer required to provide separate stations for forming the capsule bodies 12 and the filtering elements 13.

(33) Furthermore, the simultaneously forming of the capsule bodies 12 and of the respective filtering elements 13, reduces to the minimum the production rejects, with respect to the methods and apparatuses known in the state of the art. It should be noted that if the first film 6 of thermoplastic material and the second film 8 of filtering material are heated together, it is possible, using heating plates 10, to weld the two films together before they arrive to the forming mold 1, exerting a pressure by means of heating plates 10.

(34) Thereby the first film of thermoplastic material 6 and the second film 8 of filtering material, being joint together, undergo the same deformations during the formation of the capsule bodies 12 and filtering elements 13, both due to the action of punches, and to the action of compressed air. It is thus possible to obtain filtering elements 13 which substantially have the same shape and size of capsule bodies 12.