Patent Publication Number: US-10315785-B2

Title: Unit and method for filling containers forming single-use capsules for extraction or infusion beverages

Description:
This application is a national phase of International Application No. PCT/IB2015/050816 filed Feb. 2, 2015 and published in the English language, which claims priority to Italian Patent Application No. BO2014A000052 filed Feb. 6, 2014, which are hereby incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     This invention relates to a unit and a method for filling containers with a dose of product. Advantageously, the containers may define single-use capsules for extraction or infusion beverages. 
     BACKGROUND ART 
     The prior art capsules, used in machines for making extraction or infusion beverages, comprise in their simplest form, the following:
         a rigid, cup-shaped outer container comprising a perforatable or perforated bottom and an upper aperture provided with a rim (and usually, but not necessarily, having the shape of a truncated cone);   a dose of product for extract or infusion beverages contained in the outer container;   and a length of sheet obtained from a web for sealing (hermetically) the aperture of the rigid container and designed (usually but not necessarily) to be perforated by a nozzle which supplies liquid under pressure.       

     Usually, but not necessarily, the sealing sheet is obtained from a web of flexible material. 
     In some cases, the capsules may comprise one or more rigid or flexible filtering elements. 
     For example, a first filter (if present) may be located on the bottom of the rigid container. A second filter (if present) may be interposed between the piece of sealing sheet and the product dose. 
     The dose of product may be in direct contact with the rigid, cup-shaped outer container, or with a filtering element. 
     The capsule made up in this way is received and used in specific slots in machines for making beverages. 
     In the technical sector in question, the need is particularly felt for filling in a simple and effective way the rigid, cup-shaped containers or the filtering elements whilst at the same time maintaining a high productivity. 
     It should be noted that, in this regard, there are prior art packaging machines having a filling unit which allows the simultaneous filling of several parallel rows of rigid, cup-shaped containers, which are advancing. In this case, each row of rigid, cup-shaped containers is associated with a dedicated filling device, generally equipped with a screw feeder to allow the descent of the product inside the container. 
     This type of unit is therefore obviously quite expensive and complex, since it comprises a plurality of devices and drives (one for each screw device) which are independent from each other and which must necessarily be coordinated. 
     Moreover, the overall reliability of the machine resulting from this configuration/arrangement of elements is necessarily limited because the rate of faults is inevitably linked with the number of devices and drives present. 
     Moreover, the screw feeder devices may have drawbacks due to clogging, soiling and poor dosing accuracy. More in detail, the end part of the screw feeder is not normally able to retain the product, which therefore falls and soils the machine. 
     A strongly felt need by operators in this sector is that of having a unit and a method for filling containers (rigid, cup-shaped containers, or filtration elements) forming single-use capsules for extraction or infusion beverages which are particularly simple, reliable and inexpensive and at the same time maintain a high overall productivity. 
     AIM OF THE INVENTION 
     The aim of this invention is therefore to satisfy the above-mentioned need by providing a unit and a method for filling containers (rigid, cup-shaped containers) forming single-use capsules for extraction or infusion beverages which can be made relatively simply and inexpensively and which is particularly reliable. 
     Another aim of the invention is to provide a machine for packaging single-use capsules for extraction or infusion beverages which can guarantee a high productivity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The technical features of the invention, with reference to the above aims, are clearly described in the claims below and its advantages are apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate a non-limiting example embodiment of the invention and in which: 
         FIG. 1  is a schematic view of a machine for packaging containing elements of single-use capsules for extraction or infusion beverages comprising a filling unit according to a preferred embodiment of the invention; 
         FIG. 2  is a schematic view of a single-use capsule for beverages which can be made by the machine of  FIG. 1 ; 
         FIG. 3  is a schematic side view of the filling unit present in the machine according to the invention and present in the machine of  FIG. 1 ; 
         FIGS. 4 to 8  show respective side views partly in cross section of the filling unit of  FIG. 3  according to different operating steps; 
         FIG. 9  shows an enlargement of a detail of the filling unit of the preceding figures; 
         FIGS. 10 and 12  are plan views of some components of the filling unit of the preceding figures. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
     With reference to the accompanying drawings, the numeral  1  denotes a unit for filling containers  2  forming single-use capsules  3  for extraction or infusion beverages, with a dose  33  of solid product in powder, granules or leaves, such as coffee, tea, milk, chocolate, or combinations of these. 
     The filling unit  1  is particularly suitable for filling containers  2  forming single-use capsules  3  with products in powder, preferably coffee. 
     More specifically, as illustrated in  FIG. 2 , the single-use capsules  3  for extraction or infusion beverages comprise, in a minimum, but non-limiting, embodiment: a rigid, cup-shaped container  2  (usually to define a frustoconical shape) comprising a base  30  and an upper opening  31  equipped with a collar  32 ; a dose  33  of extraction or infusion product contained in the rigid container  2  and a lid  34  for closing the upper opening  31  of the rigid container  2 . 
     The capsule  3  may comprise one or more filtering or product retaining elements (not illustrated here for simplicity reasons). 
     In the capsule  3  illustrated in  FIG. 2 , the rigid, cup-shaped body  2  defines the container to be filled with a dose  33  of product. 
     Other types of capsules may be filled with the filling unit according to the invention, for example capsules wherein the dose  33  of product is contained in, and retained by, a filtering element connected to the rigid container, wherein the rigid container can be closed at the bottom, or open. 
     In other words, in capsules not illustrated, a filtering element may contain and retain the dose  33  of product, forming the container in combination with the rigid body with which it is coupled. 
     In the following description, reference will be made to the rigid, cup-shaped body  2  as the container, but it is understood that the invention can be made with reference to capsules wherein the container is formed by a filtering element (or other components of the capsule designed to contain a dose  33  of product) and by the respective rigid body to which it is connected. 
     It should be noted that the filling unit  1  comprises a line  4  for transport (that is to say, movement) of rigid, cup-shaped containers  2  designed to contain a predetermined quantity of extraction or infusion product (dose  33 ) and a filling station SR. 
     The transport line  4  extends along a first movement path P and is provided with a plurality of seats  5  for supporting the rigid containers  2 , arranged in succession along the first path P. Preferably, the first movement path P is a closed path lying on a horizontal plane. 
     The supporting seats  5  are arranged one after another, not necessarily continuously. In addition, the supporting seats  5  each have a corresponding vertical axis of extension. 
     The transport line  4  comprises a transport element  39  to which the supporting seats  5  are connected to be moved along the first path P. 
     The transport element  39  is closed in a loop around movement means  17  which rotate about vertical axes for moving the transport element  39 . 
     Preferably, the transport element  39  is a chain  40  comprising a plurality of links, hinged to one another in succession about corresponding vertical axes, to form an endless loop. 
     At least one of the links comprises at least one supporting seat  5  with a vertical axis for corresponding rigid container  2  which can be positioned with the opening  31  facing upwards. 
     It should be noted that the chain  40  may comprise both links having a corresponding supporting seat  5  and connecting links which are not provided with supporting seats  5  and which are interposed between links provided with supporting seats  5 . Therefore, preferably, a certain number of links comprises each supporting seat  5 . 
     Alternatively, in an embodiment not illustrated, the transport element  39  may comprise a flexible belt to which the supporting seats  5  for the rigid containers  2  are fixed. 
     Preferably, but not necessarily, the movement means  17  rotate continuously about vertical axes to allow the transport element  39  to move continuously. 
     Described below is the station SR for filling the rigid, cup-shaped containers  2 . 
     The station SR for filling the rigid, cup-shaped containers  2  comprises:
         at least one first containing seat S 1  (hereinafter referred to as first seat S 1  or also as a first receiving seat S 1 ) designed to receive a dose  33  of product;   a device  10  for moving the first seat S 1  along a closed path PS;   a device  11  for adjusting the position of the first seat S 1 , configured for adjusting the position of the first seat S 1  along the closed path PS, between a position P 1  for receiving the dose  33  and a position P 2  for releasing the dose  33  inside one of the containers  2 ;   a substation ST 1  for forming the dose  33  inside the at least one first containing seat S 1 , provided with a device  6  for releasing a predetermined quantity of product forming the dose  33  inside the at least one first containing seat S 1  located in the position P 1  for reception of the dose;   a substation ST 3  for releasing the dose  33  of product from the at least one containing seat S 1  positioned in the position P 2  for releasing the dose to a container  2  transported by the transport line  4 ;       

     It should be noted that for reasons of clarity, only part of the product in the release device  6  is illustrated in  FIGS. 3 to 5 . In reality, the release device  6  is, in operating conditions, normally full of product to be dosed. 
     The device  11  for adjusting the position is configured to place the at least one first seat S 1  in the position P 1  for receiving at the substation ST 1  for forming the dose  33  and in the position P 2  for releasing the dose at the substation ST 3  for releasing the dose  33 . 
     All the above-mentioned components forming part of the filling station SR of the rigid, cup-shaped containers  2  are described below in more detail, with particular reference to the accompanying drawings. 
     It should be noted that the device  10  for moving the first containing seat S 1  comprises a first element  9  rotating about a first axis X 1  of rotation which is substantially vertical, on which is connected the first containing seat S 1  to be rotated about the first vertical axis X 1  of rotation. 
     The first element  9  comprises a wheel, and the movement device includes the wheel connected to a driver for driving the rotation (for example, connected to a drive unit, not illustrated here). 
     The first seats S 1  are connected radially to the first rotary element  9  to be rotated with it. Preferably, the first seats S 1  are positioned along an arc of a circle of the rotary element  9 , even more preferably they are positioned along the entire circumference having as the centre a point of the first axis X 1 . 
     Still more preferably, the first seats S 1  are angularly equispaced from each other along a circumference having as the centre a point of the first axis X 1 . 
     It should be noted that each first seat S 1  is moved by the first rotary element  9  in rotation so as to engage cyclically—during the rotation—the substations for forming ST 1  and releasing ST 3  the dose. 
     In the embodiment illustrated in the accompanying drawings, the first containing seats S 1  are supported by the first rotary element  9  in a radially movable fashion. 
     According to this aspect, the adjustment device  11  is configured to move the at least one first seat S 1  radially relative to the first axis X 1  of rotation between the position P 1  for receiving the dose and the position P 2  for releasing the dose. 
     More specifically, the adjustment device  11  is configured to move the at least one first seat S 1  radially in a forward stroke from the position P 1  for receiving the dose to the position P 2  for releasing the dose and according to a return stroke from the position P 2  for releasing the dose to the position P 1  receiving the dose. 
     In the embodiment illustrated, the first seat S 1  is formed in an element  20  for containing the dose (preferably having an elongate shape). 
     Preferably, the first seat S 1  is a through seat. 
     In other words, the first through seat S 1  extends between an upper face and a lower face of the above-mentioned element  20  for containing the dose. 
     Preferably, the first seat S 1  has a cylindrical shape, that is, it has a circular cross section. 
     According to another aspect, the filling unit  1  comprises an element  21  for housing the element  20  for containing the dose, provided with openings upper ( 23 A,  23 B) and lower openings ( 22 A,  22 B). 
     Preferably, the housing element  21  is fixed to the rotary element  9 , in such a way as to be rotated by the rotary element without the position being modified. 
     In practice, the housing element  21  defines a housing cavity, inside of which the element  20  for containing the dose is movably inserted to be movable between the position P 1  for receiving the dose and the position P 2  for releasing the dose. 
     Advantageously, the containing element  20  is movable on a horizontal plane. 
     A rotation of the rotary element  9  determines a rotation of the containing  21  and housing  20  elements. 
     The filling unit  1  also comprises a track, or cam,  57  having side walls  11 A,  11 B facing each other. The track  57  extends on a closed-loop path. 
     The element  20  for containing the dose is configured for engaging in the track  57  in such a way that the position of the element  20  for containing the dose along the closed path PS can be adjusted. 
     It should be noted that the track  57  is fixed relative to the frame  29  of the filling unit  1 , that is, it is not rotated as one with the rotary element  9 . 
     In practice, it should be noted that the element  20  for containing the dose is equipped with a portion, or cam follower,  20   a  designed to be inserted in the track  57 . 
     It should be noted that the portion  20   a  and the track  57  define, in combination, a cam device configured for adjusting the position of the first seat S 1  along the closed path PS. 
     It should also be noted that the containing element  20 , the housing element  21  and the cam device ( 20   a ,  57 ) define the above-mentioned device  11  for adjusting the position of the first seat S 1  along the closed path PS. 
     It should also be noted that the housing element  21  comprises an upper wall  50 , provided with a first upper opening  23 A and a second upper opening  23 B. 
     The first upper opening  23 A is located in a position close to the axis X 1 , whilst the second upper opening  23 B is located in a position far from the axis X 1 . 
     The housing element  21  also comprises a lower wall  51 , provided with a first lower opening  22 A and a second lower opening  22 B. 
     The first lower opening  22 A is located in a position close to the axis X 1 , whilst the second lower opening  22 B is located in a position far from the axis X 1 . 
     Preferably, the first upper opening  23 A is vertically superposed on the first lower opening  22 A. Preferably, the second upper opening  23 B is vertically superposed on the second lower opening  22 B. 
     The first and second openings ( 22 A,  22 B,  23 A,  23 B), are in communication with the housing cavity defined by the housing element  21  and inside of which the containing element  20  can move radially. 
     The containing element  20 , therefore the first seat S 1 , is movable in such a way as to be positioned:
         in the first position P 1  for receiving the dose  33 , in a condition of vertical alignment with the first upper opening  23 A and the first lower opening  22 A, and   in the second position P 2  for receiving the dose  33 , in a condition of vertical alignment with the second upper opening  23 B and the second lower opening  22 B.       

     In other words, when the first seat S 1  is positioned vertically aligned with the first upper openings  23 A and lower openings  22 A, the first seat S 1  is in the position P 1  for receiving the dose, whilst when first seat S 1  is positioned vertically aligned with the second upper openings  23 B and lower openings  22 B the first seat S 1  is in the position P 2  for releasing the dose  33 . 
     Each first seat S 1  is defined, preferably, by lateral walls of a cavity  18  and by a bottom wall F (the bottom wall F is a movable wall, that is to say, it may be defined by one or more elements as a function of the position of the first seat). 
     Preferably, the cavity  18  is a cylindrical cavity. 
     Furthermore, still more preferably, the cavity  18  has a vertical axis of extension (parallel to the first axis X 1  of rotation). 
     Again, preferably, the filling station SR comprises, for each first seat S 1 :
         a first piston  13 , which is movable between a lower position and an upper position and forming the above-mentioned bottom wall F of the first seat S 1  when the first seat S 1  is in the position P 1  for receiving the dose;   means  14  for moving the first piston  13  for moving the first piston  13  between the lower and upper positions in such a way as to adjust the volume inside the first seat S 1 .       

     Examples of movement means  14  are electric motors, pneumatic devices, cam devices, and other prior art devices. 
     Preferably, but not necessarily, the filling station SR comprises movement means  14  which are independent for each first piston  13 , so that each piston  13  can be moved independently of the others. 
     It should be noted that each first piston  13  is rotated by the rotary element  9 . 
     More specifically, the first pistons  13  are positioned in a predetermined radial position relative to the axis X 1  of the rotary element  13 . 
     According to another aspect, the filling unit  1  comprises a control unit  15 , designed to control one or more moving elements of the unit. 
     The control unit  15  is configured to control, when the first seat S 1  is positioned at the substation ST 1  for forming the dose, the movement of the first piston  13  to place it in a predetermined position corresponding to a desired internal volume of the first seat S 1 . 
     In practice, as described in more detail below, the first piston  13  is positioned at a predetermined height, so that the first seat S 1  has a predetermined and desired internal volume (which is filled by a predetermined quantity of product). 
     It should also be noted that the first piston  13  defines the bottom F of the first seat S 1  at least at the forming substation ST 1 . 
     When the containing element  20  is moved from the first receiving position P 1  to the second release position P 2 , the bottom wall  51  of the housing element  21  defines the bottom F of the first seat S 1 . 
     The forming ST 1  and release ST 3  substations of the dose  33  are positioned along the periphery of the first rotary element  9 , in such a way as to be engaged cyclically by the first seats S 1  during rotation around the first axis X 1 . 
     More specifically, the forming ST 1  and release ST 3  substations of the dose are arranged in a predetermined position relative to a frame  29  of the filling station SR, along the closed movement path P 1  of the first seats S 1 . In a complete rotation of the first rotary element  9  each first seat S 1  is positioned in the forming substation ST 1  of the dose and in the release substation ST 3  of the dose. 
     Advantageously, the filling unit  1  further comprises a substation ST 2  for compacting the dose, configured to compact the dose inside the first seat S 1 . In alternative embodiments not illustrated, the station ST 2  for compacting the dose can be omitted. 
     The compacting substation ST 2  is located along the closed path PS between the substation ST 1  for forming the dose and the substation ST 3  for releasing the dose. 
     More specifically, the first seat S 1  during rotation intercepts firstly (that is, it is positioned at) the forming station ST 1 , then the compacting station ST 2  and lastly the substation ST 3  for releasing the dose. 
     Preferably, the closed path PS is a curved path around the first axis X 1 . 
     Preferably, the closed path PS is a substantially circular path around the first axis X 1 . 
     Still more preferably, the closed path PS lies on a horizontal plane. 
     Described below is the substation ST 1  for forming the dose  33 . 
     The substation ST 1  for forming the dose  33  is positioned in a region R 1  for forming the dose  33 . 
     At the substation ST 1  for forming the dose  33  there is the release device  6 , designed for releasing a predetermined quantity of product (defining the dose  33 ) inside the containing seat S 1  positioned in the region R 1  for forming the dose  33 . 
     The releasing device  6  according to a first embodiment comprises a hopper  38  (filled, in use, with loose product) having at the bottom an outfeed for the product. 
     It should be noted that the hopper  38  is configured to create a layer of product at the region R 1  for forming the dose  33  above the first seats S 1 , so as to release the product inside the first seat(s) S 1  positioned, each time, in the forming region R 1 . 
     More specifically, the outfeed of the hopper  38  is shaped in such a way as to occupy a portion of the closed movement path P 1  of the first seats S 1 . 
     More specifically, according to one embodiment, the outfeed of the hopper is in the form of an arc, centred on the first axis X 1 . 
     The outfeed of the hopper  38  releases the product to a plurality of first seats S 1  positioned temporarily in the region R 1 , that is to say, opposite below the outfeed of the hopper  38 . 
     In other words, the first seats S 1 , passing below the hopper  38 , are filled with product, in a filling time which depends on the speed of transit of the first seats S 1  in the forming region R 1  and on the amplitude of the portion of the closed movement path PS of the first seats S 1  occupied by the outfeed  19  of the hopper  38 . 
     According to one embodiment, the release device  6  comprises at least a first rotary element  40   a , designed to rotate about its axis of rotation X 4 . 
     The first axis of rotation X 4  of the first rotary element  40   a  is fixed relative to the hopper  38 , or equally, to the frame  29 . 
     The first rotary element  40   a  is configured to create a flow of product under pressure which intercepts the at least one first seat S 1  and to release the product inside the at least one first containing seat S 1  in transit through the region R 1  for forming the dose. 
     Preferably, the first rotary element  40   a  is operating in the region R 1  for forming the dose on a seat S 1 , or on a plurality of seats S 1  simultaneously in transit through the forming region R 1 . 
     It should be noted that the release device  6  also comprises drive means (such as, for example, a first drive unit), operatively coupled to the first rotary element  40   a  to rotate the rotary element  40   a.    
     The first rotary element  40   a  preferably comprises an element  41   a  which defines a surface with a helical extension. 
     The helical surface extends—in a spiral shape—along the first axis of rotation X 4  of the first rotary element  40   a.    
     The first rotary element  40   a  also comprises a respective first shaft  42   a , to which the element  41   a  is connected, defining a surface with a helical extension for being rotated. 
     The first shaft  42   a  is supported rotatably relative to the frame  29  of the filling unit  1 . 
     The first shaft  42   a  extends along the first axis of rotation X 4  of the first rotary element  40   a.    
     It should be noted that the first rotary element  40   a  described above defines a screw feeder, which by rotation about the first axis of rotation X 4  allows a feeding of the product along the direction of axial extension of the first axis of rotation X 4 . 
     According to a preferred embodiment, the first axis of rotation X 4  of the first rotary element  40   a  is inclined relative to a horizontal plane. It should be noted that, in this embodiment, the product is fed from the first rotary element  40   a  angularly, according to the direction of extension of the axis of rotation X 4 , so that the motion of the product has, as well as a horizontal component, also a vertical component which favours the insertion of the product inside the first seat S 1  in transit in the region R 1  for forming the dose (slightly compressing the product inside the first seat S 1 ). 
     The helical element  41   a  of the first rotary element  40   a  is rotated in such a way that the product is pushed, along the direction of extension of the first axis X 4  of rotation, in such a way as to create a flow of product under pressure inside the hopper  38 , the flow intercepting the first seat S 1  to be filled, thereby filling the first seat S 1 . 
     It should be noted that the first rotary element  40   a  defines a unit for feeding the product inside the first seat S 1 . 
     In a first embodiment, the release device  6  comprises, in addition to the first rotary element  40   a , a second rotary element  40   b , designed to rotate about a relative second axis of rotation X 5  ( FIG. 12 ). 
     It should be noted that the release device  6  also comprises drive means, operatively coupled to the first rotary element  40   a  and to the second rotary element  40   b  to rotate the second rotary element  40   b.    
     The second axis of rotation X 5  of the second rotary element  40   b  is parallel to the first axis X 4 . 
     With regard to the second rotary element  40   b , all the considerations and the technical and functional features described with reference to the first rotary element  40   a  apply. 
     It should be noted that each of the two rotary elements ( 40   a ,  40   b ) is equipped with a respective helical element ( 41   a ,  41   b ) and a respective shaft ( 42   a ,  42   b ), to which a respective helical is connected for being rotated. 
     The second shaft  42   b  is supported rotatably relative to the frame  29  of the filling unit  1 . 
     The second shaft  42   b  extends along the second axis of rotation X 5  of the second rotary element  40   b.    
     The second rotary element  40   b  also defines a screw feeder, which by rotation about the second axis of rotation X 5  allows a feeding of the product along the direction of axial extension of the second axis of rotation X 5 . 
     Advantageously, the first rotary element  40   a  and the second rotary element  40   b  rotate accordantly, or discordantly. 
     It should be noted that the shafts  42   a ,  42   b  of the first and the second rotary element  40   a ,  40   b  are parallel to each other. 
     According to yet another aspect, it should be noted that the control unit  15  of the unit  1  (which advantageously also controls the machine  100 ) is designed to rotate the at least one first rotary element  40   a  of the release device  6  (and preferably also the second rotary element  40   b ) with a speed depending on the speed of movement of the first seat S 1  by the first rotary unit  9 . 
     Further, according to another aspect of the invention, the control unit  15  of the machine  100  is designed to rotate the at least one first rotary element  40   a  of the release device  6  (and preferably also the second rotary element  40   b ) with variable speed as a function of the quantity of product to be inserted inside each first seat S 1 . 
     More in detail, it is possible to increase the quantity of product inserted inside each seat S 1  by increasing the speed of rotation of the first and/or secondary rotary element  40   a ,  40   b , in such a way as to increase the apparent density of the product, and vice versa. 
     In other words, it is possible to vary the quantity of product contained in the first seat S 1 , and hence in the capsules  3 , by adjusting the speed of rotation of the at least one first rotary element  40   a  (and second rotary element  40   b ). 
     The rotary element ( 40   a ,  40   b ) is associated with (positioned inside) the hopper  38 , which also forms part of the release device  6 . 
     It should be noted that the hopper  38  is defined by corresponding side walls, which are vertical and/or inclined. 
     More specifically, in the embodiment shown in the accompanying drawings, the filling unit  1  comprises a hopper  38  to which the first rotary element  40   a  and the second rotary element  40   b  are associated (positioned inside). 
     It should be noted that, advantageously, the presence of one or more rotary elements  40   a ,  40   b  prevents the product, in particular with powder type products (such as, for example, coffee), from creating blockages, that is, build-ups, inside the hopper which render incomplete the filling of the first seats S 1  in transit through the region R 1  for forming the dose. Indeed, it should be noted that the one or more rotary elements  40   a ,  40   b  are rotated so as to move the product and prevent the formation of any blockage inside the hopper  38  for feeding the product. In this way, advantageously, the speed at which the unit  1  may be used is particularly high and, consequently, the unit  1  is particularly fast and reliable in its operation. 
     With reference to the movement of the piston  13  in the region R 1  for forming the dose, the following should be noted. 
     Preferably, when the above-mentioned first seat S 1  is inside the region R 1  for forming the dose, in particular at the infeed zone, the first piston  13  associated with the first seat S 1  is positioned in a predetermined position (vertical) wherein it defines a predetermined space in the first seat S 1 . 
     According to a possible operating mode, the first piston  13  can be moved (vertically) from the top downwards in such a way that the first seat S 1  is filled, not only by gravity acting on the product which causes the product to enter the seat S 1 , but also due to the suction effect on the product caused by the movement (displacement) of the piston  13  from an upper position to the desired (lower) position. 
     In this way, advantageously, thanks to the additional suction effect due to the lowering of the first piston  13 , the resulting speed of the machine  100  at the filling station SR, in particular at the substation ST 1  for forming the dose, is particularly high. 
     According to this invention, by varying the position (vertical) of the piston  13  by means of the movement means  14  in the region R 1  for forming the dose  33  it is possible to vary the quantity of product contained in the first seats S 1 , or in other words, it is possible to vary the dose  33 . Basically, the movement means  14  are designed to position the piston  13  in a desired dosing position at an outfeed zone of the region R 1  for forming the dose  33 , wherein a levelling element of the hopper  38  defines the dose  33 . With reference to the compacting substation ST 2 , it should be noted that the compacting substation ST 2  is equipped with compacting means  101  designed to compress the product, in phase with the piston  13 , inside the first seat S 1 . 
     The compacting means  101  are described below in more detail. 
     In the example described, the compacting means  101  comprise a compacting element  26 . 
     The compacting element  26 , in the preferred embodiment illustrated, comprises a compacting piston. 
     It should be noted that the compacting element  26  is connected to the (carried by the) rotary element  9  of the filling station SR. 
     In practice, the compacting element  26  is rotated by the rotary element  9 , as one with the first seat S 1 . 
     More specifically, the filling unit  1  preferably comprises a compacting element  26  associated with every containing seat S 1 . 
     The compacting element  26  is movable vertically, between a raised non-operating position and a lowered operating position. 
     It should be noted that the compacting element  26  is positioned in the lowered operating position at the substation ST 2  for compacting the dose. 
     The compacting element  26  is positioned above the first piston  13 . 
     In practice, the compacting element  26  is positioned relative to the rotary element  9  in a position such that in the lowered operating position it can be inserted through the first upper opening  23 A of the upper wall  50  of the housing element  21 . 
     On the other hand, the first piston  13  is positioned relative to the rotary element  9  in a position such that the first piston  13  can pass through the first lower opening  22 A of the lower wall  51  of the housing element  21 . 
     It should be noted that the lower face of the compacting element  26  defines, at the compacting region R 2 , an upper contact element of the dose  33  positioned inside the first seat S 1 , so as to compact the product. 
     In other words, the dose S 1  is compressed between the first piston  13  and the compacting element  26 , by the action of the compression applied by the latter. 
     Alternatively, once the dose  33  is formed, the first piston  13  can be moved to compact the product and the compacting element  26  act as a fixed contact element for the first piston  13 . In other words, the drive and control unit  15  can move one or other, or both, between the first piston  13  and the compacting element  26  for compressing the dose  33 . 
     It should also be noted that, according to an embodiment not illustrated, the filling unit  1  comprises a single compacting element  26  which is stationary relative to the frame  29  (that is, it is not rotated by the rotary element  9 ). 
     Alternatively, according to an embodiment not illustrated, the compacting element  26  may be omitted and replaced by an upper fixed contact element, for example a plate stationary relative to the frame  29 . 
     According to another aspect, advantageously, the filling unit  1  further comprises at least one ejection device  36  movable at the substation ST 3  for releasing the dose to abut (at the top) the dose  33  inside the at least one first containing seat S 1  and eject it to the outside of the first seat S 1  so as to release it inside the containing element  2  (located under the first seat S 1  waiting). 
     Advantageously, the ejection device  36  is movable vertically. 
     More specifically, according to the embodiment illustrated in the accompanying drawings, the filling unit  1  comprises a plurality of ejection devices  36 , with each of the ejection devices  36  being associated with a first seat S 1 . 
     Preferably, the ejection devices  36  comprise a piston, configured to abut the top of the dose  33  inside the first seat S 1  at the substation ST 3  for releasing the dose. 
     It should be noted that at the substation ST 3  for releasing the dose, the closed path PS of the first seat S 1  is positioned above the first movement path P of the transport line  4  (and hence of the containers  2 ). 
     These ejection devices  36  are movable between an upper non-operating position and a lower operating position, wherein they make contact (at the top) with the dose  33  inside the seat S 1  to cause the ejection. 
     It should be noted that the ejection device  36  is positioned in the lowered operating position at the substation ST 3  for releasing the dose  33 , as described in more detail below. 
     The ejection device  36  is located above a piston  23  for lifting the container  2 . 
     It should be noted that the unit  1  also comprises a piston  23  for lifting the container  2 , which is movable at the substation ST 3  for releasing the dose between a lower position and an upper position for lifting the container  2 . 
     Advantageously, the lifting piston  23  is movable vertically. 
     Preferably, the filling unit  1  comprises a lifting piston  23  for each first containing seat S 1 ; preferably, each piston  23  rotated by the rotary element  9  as one with the first seat S 1 . The lifting piston  23  may be driven by respective actuators, or by a fixed cam. 
     In practice, the ejection device  36  is positioned relative to the housing element  21  in a position such that in the lowered operating position the ejection device  36  can be inserted through the second upper opening  23 B of the upper wall  50 . 
     On the other hand, the lifting piston  23  is positioned relative to the housing element  21  in a position aligned relative to the second lower opening  22 B. 
     It should be noted that the lower face of the ejection device  36  abuts at the top, at the region R 3  for releasing the dose, the dose  33  positioned inside the first seat S 1 , in such a way as to push the product towards the outside of the seat S 1  to release the dose inside the container  2  lifted by the lifting piston  23 . 
     It should be noted that at the region R 3  for releasing the dose  33  the container  2  is raised, for moving the container  2  to the second lower opening  22 B and minimising the escape of product. 
     It should also be noted that, according to an embodiment not illustrated, advantageously in the case of step operation, the filling unit  1  comprises a single ejection device  36  which is stationary relative to the frame  29  of the unit  1 . 
     The ejection device(s)  36  is/are movable, and operate on the first seat S 1  at the release substation ST 3 . 
     According to an alternative embodiment not illustrated, the ejection device  36  may be omitted and the dose  33  may fall by gravity inside the container  2  when the seat S 1  is located at the release position P 2 , that is, when the seat S 1  is aligned with, that is, in fluid communication with, the second lower opening  22  B. 
     With reference to the compacting element(s)  26 , the ejection devices  36 , the first piston  13  and the piston lifting  23 , it should be noted that the above-mentioned elements/devices ( 26 ,  36 ) and pistons ( 13 ,  23 ) are supported (vertically movable) by the rotary element  9 , that is to say, they are positioned in a predetermined radial position. 
     The compacting element(s)  26 , ejection device(s)  36 , first piston(s)  13  and the lifting piston(s)  23  are movable vertically, as described above. 
     With reference to the filling unit  1  in its entirety, it should be noted that the unit  15  also comprises a unit (formed by one or more electronic cards) for drive and control of the devices for moving, respectively, the first seat S 1 . 
     Advantageously, the drive and control unit  15  is also configured to control the advance of the transport element  39  and the movable elements of the filling station SR (for example, the pistons  13  and  23 , the compacting elements  26  and the ejecting devices  36 ). 
     It should be noted that the drive and control unit  15  coordinates and controls the step of moving all the above-mentioned elements connected to it, so as to allow the operations described below to be performed. 
     The filling unit  1  according to the invention may advantageously form part of a packaging machine  100  (illustrated in  FIG. 1 ) designed for packaging single-use capsules for extraction or infusion beverages, for example of the type described above. The packaging machine  100  further comprises a plurality of stations, positioned along the first path P performed by the transport element  39 , configured to operate in a synchronised fashion (preferably continuously) with the transport element  39  and with the filling station SR, comprising at least:
         a station SA for feeding rigid containers  2  into corresponding seats  5  of the transport element  39 ;   a station SC for closing the rigid containers, in particular the upper opening  31  of the rigid container  2 , with a lid  34 ;   an outfeed station which picks up the capsules  3  from the respective seats  5  of the transport element  39 .       

     In addition to the stations listed above (SA, SR, SC, SU), the packaging machine  100  may comprise further stations, such as, for example, one or more weighing stations, one or more cleaning stations, one or more control stations and, depending on the type of capsule to be packaged, one or more stations for applying filtering elements. 
     The operation of the filling unit  1  is briefly described below, in particular the filling station SR, with the aim of clarifying the scope of the invention: in particular, the filling of a rigid, cup-shaped container  2  is described with reference to the embodiment illustrated in the accompanying drawings (in particular  FIGS. 4 to 8 ). 
     During movement (rotation) of the first rotary element  9 , a first seat S 1  designed to be filled with a dose  33  of product is positioned in the region R 1  for forming the dose  33 , that is to say, in the proximity of the substation ST 1  for forming the dose  33 . 
     It should be noted that the feeding device  6  feeds product in the region R 1  for forming the dose  33 , filling the first seat S 1  at the forming region R 1 . 
     The movement of the first rotary element  9  is, preferably, a continuous type movement. Alternatively, the movement of the first rotary element  9  is of a step type. 
     More specifically, the first seat S 1  is completely filled at the outfeed of the region R 1  for forming the dose  33 . 
     Advantageously, once the seat S 1  has been filled, the filling unit  1  can operate a step for compacting the dose  33 . 
     More specifically, from the substation ST 1  for forming the dose, a rotation of the rotary element  9  by a predetermined angle moves the first seat from the substation ST 1  for forming the dose to the substation ST 2  for compacting the dose. 
     It should be noted that the containing element  20  (that is, the first seat S 1 ) is kept in the position P 1  for receiving the dose both at the substation ST 1  for forming the dose and at the substation ST 2  for compacting the dose. 
     At the compacting substation ST 2 , the compacting element  26  is moved from the top downwards, through the first upper opening  23 A of the upper wall  21  of the housing element  50 , until abutting the top of the dose  33  inside the first seat S 1 , to compact the dose. 
     The dose S 1  is in effect inside the first seat S 1  and supported by the first piston  13 : the combined action of supporting the first piston  13  and compressing the compacting element  26  allows the dose to be compressed to a predetermined value. 
     Alternatively, the ejecting device  36  may act as upper contact for the dose  33  which is compressed by the action of the first piston  13 . In other words, the dose  33  is compacted by moving one or other, or both, between the first piston  13  and compacting element  26 , towards each other. 
     In practice, the dose  33  is subjected to a desired compression which determines a reduction in volume, so as to be able to dose more product inside the container  2 . 
     The compacting element  26 , after the compression is performed, is raised so as to come out of the seat S 1 . 
     At this point, the first seat S 1 —following a further rotation of the rotary element  9 —is moved by rotation to the release substation ST 3 . 
     Simultaneously with that rotation, or immediately before or after, the position of the first seat S 1  is adjusted in such a way as to move the first seat S 1  from the position P 1  for receiving the dose to the position P 2  for releasing the dose. 
     In other words, the element  20 , that is, the first seat S 1 , is moved radially, in such a way that the first seat S 1  is positioned in the position P 2  for releasing the dose at the substation ST 3  for releasing the dose. 
     In the release position P 2 , the first seat S 1 , the second upper opening  23 B and the second lower opening  22 B are superposed on each other (that is, they occupy a shared region in plan). 
     Advantageously, at the release region/substation (R 3 /ST 3 ) the lifting piston  23  is moved from the lowered position to the raised position, in such a way as to lift a container  2  not yet filled with product (and which must be filled with the product). 
     In order to perform the transfer, for a period of time depending on the speed of rotation of the rotary element  9 , the first seat S 1 , the seat  5  of the chain  40  which carries the container  2  to be filled, the lifting piston  23  and the ejection device  36  are positioned superposed (at different heights) at the region R 3  for releasing the dose. 
     The release of the dose  33  of product from the first seat S 1  to the containing element  2  is described below. 
     The lifting piston  23  abuts the bottom of the container  2  in such a way as to lift the container  2 . 
     It should be noted that the lifting piston  23  is moved (from the bottom upwards, that is, vertically) until the container  2  comes into contact with, that is moves close to, a tubular element  53  which extends downwards from the second lower opening  22 B. 
     More specifically, the container  2  is positioned in such a way that the tubular element  53  is partially located inside it. 
     Advantageously, there is a transit gap between the tubular element  53  and the container  2  in a raised position, designed to minimise the escape of product from the container  2 , but at the same time allow air to pass through during the release of the dose  33 . 
     In practice, the tubular element  53  forms an extension of the second lower opening  22 B; in more detail, the element  53  constitutes a channel for releasing the product from the first seat S 1  to the container  2 . 
     Once the first containing seat S 1  is in release position P 2 , the dose  33  falls, or is pushed, towards the container  2  positioned below the tubular element  53 , that is, to the second lower opening  22 B. 
     Advantageously, so as to favour the transfer of the product from the first seat S 1  to the container  2 , the ejection device  36  is moved from the non-operating raised position to the lowered operating position. 
     During the movement from the non-operating raised position to the lowered operating position, the ejection device  36  comes into contact with the dose  33  of product which is positioned inside the first seat S 1 , pushing it downwards and encouraging the escape from the first seat S 1 . 
     The dose  33  is transferred from the first seat S 1  to the containing element  2 . 
     It should be noted that at the step of transferring the dose  33  from the first seat S 1  to the container  2 , the seat S 1  and the container  2  are moved along superposed trajectories, in such a way that the container  2  is positioned below the first seat S 1  for a shared stretch. 
     It should be noted that, after the transfer, a flow of air is preferably released on the collar  32  (upper edge) of the container  2 . 
     For that purpose, the filling unit  1  comprises means  55  for releasing fluid, that is, air or inert gases, such as for example, nitrogen, CO2, etc., operatively associated with the release station ST 3  to release a flow of fluid on the collar  32  of the container  2 . 
     It should be noted that the ejection device  36 , when the flow of fluid is released on the container  2 , is in the lowered operating position. 
     More specifically, when the flow of fluid is released on the containing element  2 , the container  2  is preferably closed by the tubular element  53 , thereby preventing escape of product. 
     It should be noted that the release of the flow of air (by the fluid release means  55 ) means that the containing collar  32  of the container  2  is cleaned, in such a way that it is in perfect order for the subsequent operations, in particular for the operation of sealing a piece  34  of sealing sheet to the collar  32 . 
     With reference to this aspect, it should be noted that the means  55  for releasing the fluid preferably comprise a nozzle  56  (clearly visible in  FIG. 9 ). Preferably, the nozzle  56  is associated with the tubular element  53 . Preferably, at least one nozzle  56  is associated with each tubular element  53 . 
     Advantageously, the fluid release means  55  preferably comprise a source (not illustrated) fluid, such as nitrogen, CO2, other inert gases or air under pressure and a plurality of nozzles  56  in fluid connection with the source, so as to allow the release of pressurised fluid. 
     After transfer, the lifting piston  23  is moved from the raised position to the lowered position, so as to move the container  2  inside, and resting against, the respective seat  5  of the chain  40 . 
     It should be noted that the filling unit  1  according to this invention is particularly simple in terms of construction and at the same time is extremely flexible, and can easily adapt to different types of products and capsules. 
     According to this invention, a method is also defined for filling containers forming single-use capsules for extraction or infusion beverages. As stated above, the term “containers” is deemed to mean both rigid, cup-shaped containers  2 , of the type shown, and elements for filtration or retention of a dose of product connected to a rigid container. 
     The method according to the invention comprises the following steps:
         moving a succession of containers  2  along a first movement path P;   moving at least one first receiving seat S 1  designed to receive a dose  33  of product along a closed path PS, the moving comprising a rotation of the at least one first containing seat S 1  about a first substantially vertical axis of rotation X 1 ;   creating a dose  33  of product inside the at least one first containing seat S 1  at a region R 1  for forming the dose located along the closed path PS by releasing product inside the at least one first containing seat S 1 ;   adjusting the position of the first seat S 1  for receiving the product along the closed path PS, for positioning the first seat S 1  in a position P 1  for receiving the product at a predetermined region R 1  for forming the dose of the closed path PS and a position R 2  for releasing the dose in a container  2  at a predetermined region R 3  for transfer of the dose of the closed path PS;   releasing a dose  33  of product in a first containing seat S 1  at the region R 1  for forming the dose  33  of the path PS;   transferring the dose  33  of product from the first containing seat S 1  to a container  2  at the region R 3  for transferring the dose of the closed path PS.       

     Preferably, the step of creating the dose  33  comprises a step of releasing inside the at least one first containing seat S 1  a portion of a quantity of product accumulated loose in a hopper  38 . 
     Still more preferably, the step of creating the dose comprises a step of releasing product, inside the at least one first containing seat S 1 , using the pushing action of a screw feeder. 
     It should be noted that the dose of product (which will be released in a containing seat S 1 ) is created at the region R 1  for forming the dose starting from a mass of product, which—in terms of quantity—is able to define a plurality of doses  33 . 
     According to the method, the step of moving a succession of containers along a first movement path P preferably comprises moving the containers  2  along a path PS which is a closed loop lying on a horizontal plane. 
     Preferably, the succession of containers  2  is moved with continuous motion. 
     Moreover, the step of moving the first containing seat S 1  towards the release region R 3  comprises a rotation of the first seat S 1  about a first vertical axis X 1 . 
     Preferably, the step of transferring the dose  33  from the first seat S 1  to the container S 2  comprises a step of pushing the dose  33  (preferably using an ejection device  36 ) from the first seat S 1  to the container  2 . 
     Preferably, the pushing step comprises making contact with the dose  33  at the top and pushing the dose  33  from the top downwards, for causing the escape from the first seat S 1 . 
     According to another aspect, during the step of moving the first seat S 1  from the forming region R 1  to the release region R 3 , the method comprises a step of compacting the dose  33  inside the first seat S 1 . 
     Preferably, the compacting step comprises abutting the top of the dose  33  (preferably using a compacting element  26 ) inside the first seat S 1 . 
     According to this aspect, the compacting step comprises compressing the dose  33  inside the first seat S 1  by the combined action of a compacting element  26 , which comes into contact with the top of the dose  33 , and a first piston  13  which supports and comes into contact with the bottom of the dose  33 . In practice, the dose  33  is compressed between the compacting element  26  and the first piston  13 . 
     More generally speaking, it should be noted that the method comprises a step of compacting the dose  33  inside the first containing seat S 1  after the step of releasing a dose  33  of product inside a first seat S 1  and before the step of transferring the dose  33  of product from the first containing seat S 1  to a container  2 . 
     It should be noted that the step of compacting the dose  33  of product inside the first containing seat S 1  comprises a step of preparing a compacting element  26  and a step of moving the compacting element  26  to compress the product inside the first seat S 1 , so as to compact it. 
     Alternatively, the step of compacting the dose  33  of product inside the first containing seat S 1  comprises a step of preparing the compacting element  26  and a step of moving the first piston  13  towards the compacting element  26 , to compress the product inside the first seat S 1 , so as to compact it. 
     In a further variant embodiment, the step of compacting the dose  33  of product inside the first containing seat S 1  comprises a step of preparing the compacting element  26  and a step of moving both the first piston  13  and the compacting element  26  towards each other, to compress the product inside the first seat S 1 , so as to compact it. 
     According to another aspect, the above-mentioned step of adjusting the position of the first seat S 1  for receiving the product comprises a step of moving the first seat S 1  along a rectilinear direction according to forward and return stroke. 
     Advantageously, the rectilinear direction lies on a horizontal plane. 
     More specifically, the step of adjusting the position of the first seat S 1  for receiving the product comprises a step of moving the first seat S 1  radially relative to the first axis of rotation X 1  according to forward and return stroke. 
     According to another aspect, the step of transferring the dose  33  of product from the first seat S 1  to the container  2  comprises a step of preparing the ejection device  36  and a step of moving the ejection device  36  for pushing the dose  33  outside the first seat S 1  and releasing the dose  33  inside the container  2 . 
     The method described above is particularly simple and allows the creation of a dose  33  of product and the filling in a fast, clean and reliable manner of a container  2 , such as a rigid, cup-shaped container of a single-use capsule  3  for extraction or infusion beverages.