Device and method for testing the sealing of a container closed by a corresponding membrane

Abstract

A device for testing the tightness of receptacles (1) closed by respective membranes (2), the device comprising: a deformation unit (15) configured to exert a deformation effect on a plurality of said receptacles (1); and a detection unit (40) for detecting the deformation of the membrane (2) of each receptacle (1) subjected to the deformation action; wherein the deformation unit (15) comprises a plurality of deformation means (20), and each deformation means (20) is individually associated with a single respective receptacle (1) of the plurality of receptacles in order to exert the deformation effect.

Description

[0001] The invention relates to a device and a method for testing the tightness of a container closed by a corresponding membrane.

[0002] The entire contents of Italian patent application number 102022000012308 filed by the same applicant on June 10, 2022 and entitled “Method and apparatus for testing the tightness of a container closed by amembrane” are deemed to be incorporated herein.

[0003] The invention is preferably, but not exclusively, applied in the field of production of loose containers such as yoghurt pots, dessert pots, cups for pre-cooked food, capsules for brewed products such as coffee, to which reference may subsequently be made without loss of generality.

[0004] In the present context, the term "capsule" therefore means a product formed by a container provided with a closing membrane.

[0005] Typically, containers belonging to this technical field are products having a glass element shape, a generally inverted truncated cone shape, or an equivalent shape with the widest part of the container opening facing upward, and containers belonging to this technical field are usually made of polymer materials.

[0006] During the production of the capsule, after a filling step of the container in which the brewing product is introduced into the container through the opening, the container is sealed by applying a film which has the function of a closing lid and has a layered structure and is fixed to the edge of the container which delimits the opening.

[0007] By means of a seal which is usually carried out by welding or gluing or by an operation comprising both welding and gluing, an airtight closure of the container is obtained which allows the contents of the capsule and an inert protective atmosphere which may be introduced into the interior of the capsule to remain permanently separated from the external atmosphere, at least until the closing membrane is removed during use of the capsule or the closing membrane (if a closing membrane is provided) is perforated, i.e. the container is perforated.

[0008] In this specification and the appended claims, unless expressly stated otherwise, certain terms and expressions are deemed to have the meanings expressed in the following definitions.

[0009] The term "film" means a body having a thin-thickness sheet structure, which is used to close an opening and which is easily deformed due to a change in internal pressure or external pressure acting on the body when opened.

[0010] "Deformation of the membrane" means a change in the shape of the membrane, wherein at least part of the membrane is spaced apart from a reference plane of the container, such as a plane defined by an edge of the container to which the membrane is attached, and the distance orthogonal to the reference plane is at least a few millimeters.

[0011] A container is "hermetically closed" when it is closed gas-tightly, ie without any appreciable possibility of gas / air exchange between the interior and the exterior of the container itself.

[0012] In the packaging process of capsules, the following step is usually provided: after the steps of filling and sealing the container, a test of the leak tightness of the container closed by the film is carried out. In fact, it is essential to ensure the integrity of the leaktight closure of the capsule in order to prevent contamination or oxidation phenomena of the product contained inside the capsule or to prevent the contents themselves from possibly leaking out of the capsule. Defects that may compromise the airtight closure may for example result from ruptures or tears of the container and / or of the closing film and / or from interruptions in the welding or gluing areas of the film to the container.

[0013] Known testing systems are arranged to subject the container to a deformation effect by compression, for example by local squeezing, in a section of its handling path, along which a check station is located. A load sensor is provided in the check station and is positioned so as to come into contact with the membrane during the transport of the container in order to detect possible changes in the pressure inside the container acting on the membrane. These internal pressure changes caused by the squeezing effect actually tend to deform the membrane, for example by causing an expansion of the membrane itself. Since the pressure inside the container changes in the presence of a loss of tightness, any loss of tightness can be identified on the basis of the pressure changes detected by the detection system, due to the effect of air escaping from the container, in view of the possible abandonment of the container.

[0014] The Applicant has observed how the action of deforming the containment is essential for the realization of an effective control system for detecting any loss of tightness of the containment.

[0015] The applicant has first discovered that, since a plurality of containers are typically manipulated along a production line, for example a plurality of containers are arranged in a single-row configuration or in a multi-row configuration, a deformation action should be applied to several containers simultaneously so that the step of testing the sealing properties can be compatible with the manipulation time and speed of the containers required by a production cycle that is typically designed for high productivity.

[0016] The Applicant can also observe that both the degree and the duration of the deformation action applied to each container are relevant factors for the system used to test the tightness. On the one hand, in fact, if the container is a sealed closed container, the force used to apply the deformation - which must not destroy the container - is proportional to the increase in internal pressure, and this internal pressure is responsible for the deformation of the membrane. On the other hand, the time during which the deformation force is applied to the container - which must be compatible with the cycle time of the production line - is also a critical factor, because the time during which the deformation force is applied to the container affects the amount of air that escapes from the container in the presence of a defect. In fact, the longer the deformation force is applied, the greater the amount of air that comes out of the opening that characterizes the defect, and therefore the smaller the size of the opening that can be detected. Therefore, this factor is decisive for the identification of a loss of tightness associated with the presence of an opening with extremely reduced size.

[0017] The applicant has understood that the more uniform the deformation forces applied to the different receiving parts, the more accurate and reliable the detection of defects is. The applicant has also understood that, in order to achieve this uniformity, it is advisable to avoid, as far as possible, the receiving parts subjected to deformation being able to influence each other, for example by preventing the receiving parts that react to the deformation, in particular in the presence of a defect, from being able to influence the deformation forces applied to other receiving parts.

[0018] The Applicant has thus realised that uniformity of the deformation force applied to a plurality of containers subjected to a method for testing tightness can be obtained by applying the deformation action to containers substantially independently of one another.

[0019] The applicant has ultimately discovered that a deformation unit provided for deforming a container and comprising a plurality of deformation devices, each of which is individually associated with a single corresponding container among the plurality of containers, can ensure that as uniform a deformation effect as possible is applied to all of the plurality of containers subjected to a leak-tightness test, thereby making it possible to obtain results with greater precision and reliability in the identification of leaks that can be classified as defective.

[0020] In a first aspect of the invention, the invention therefore relates to a device for testing the tightness of a container closed by a corresponding membrane.

[0021] Preferably, the device comprises a deformation unit.

[0022] Preferably, the deformation unit is configured to exert a deformation effect on a plurality of the receiving elements.

[0023] As a result of this deformation effect, the pressure level within the container is increased if the container is a tightly closed container.

[0024] Preferably, the device comprises a detection unit for detecting the deformation of the membrane of each receiving element subjected to the deformation.

[0025] Preferably, the deformation unit comprises a plurality of deformation devices.

[0026] Preferably, each deformation means is individually associated with a single respective housing element of said plurality of housing elements for applying said deformation action.

[0027] In a second aspect of the invention, the invention relates to a method for testing the tightness of a container closed by a corresponding membrane.

[0028] Preferably, the method comprises the step of providing a deformation unit, the deformation unit comprising a plurality of deformation devices, the deformation devices being configured to exert a deformation effect on a corresponding plurality of said receiving members.

[0029] Preferably, the method comprises the step of providing a detection unit for detecting the deformation of the membrane of each receiving element that is subjected to the deformation.

[0030] Preferably, the method comprises the step of individually associating each deformation means with a single respective housing element of said plurality of housing elements to apply said deformation action.

[0031] Preferably, the method comprises the step of detecting the deformation of the membrane of each container that is subjected to deformation in order to test the tightness of the container.

[0032] Thanks to these features, the deformation action can be applied to each of the containers independently of one another, thereby ensuring the uniformity of the deformation force applied to all of the plurality of containers subjected to the leak-tightness test by appropriate control of the deformation means.

[0033] Furthermore, due to the fact that each deformation device is individually associated with a single corresponding housing, a possible failure of one of these devices does not have an impact on the others, thus ensuring the continuity of operation of the entire plant without interrupting the production line.

[0034] In at least one of the above aspects, the present invention may also have at least one of the following preferred features.

[0035] In a preferred embodiment, the apparatus further comprises a conveying device for conveying the plurality of containers toward the detection unit.

[0036] Preferably, the plurality of deformation devices are mounted on a conveying device.

[0037] Preferably, each deformation device comprises a pair of pressing elements, and the corresponding receiving piece can be positioned between the pair of pressing elements.

[0038] Preferably, the pressing element is mounted on the corresponding support in an articulated manner so that the pressing element undergoes a displacement movement away from and towards the operating position. Preferably, in the operating position, the pressing element exerts an action that causes the corresponding receiving member to deform.

[0039] Preferably, the displacement movement of the pressure element away from the operating position and towards the operating position is a swiveling movement.

[0040] In a preferred embodiment, the device comprises a control device for controlling the displacement movement of each pressure element.

[0041] Preferably, the control device comprises a cam mechanism.

[0042] Preferably, the cam mechanism comprises a corresponding cam-follower element. Preferably, the cam-follower element is rotatably supported on each pressing element. Preferably, the cam-follower element is coupled to a cam profile surface, in particular, the cam profile is common to a plurality of deformation devices.

[0043] Due to this feature, a deformation force can be exerted uniformly and in a controlled manner on each of the receiving elements associated with the respective deformation device.

[0044] Preferably, the cam profile is mounted on a fixed frame supporting the conveying device.

[0045] Preferably, the apparatus comprises a pair of cam profiles which are respectively arranged at opposite sides of the conveying device in a transverse direction with respect to a longitudinal extension of the conveying device.

[0046] In this way, a structural simplification is achieved in the control of the cam-follower element, since one cam profile in a pair of cam profiles is dedicated to the movement of a portion of the swinging pressing element in one swinging direction, while the other opposite cam profile in the pair of profiles is dedicated to the movement of the remaining portion of the swinging pressing element in the other swinging direction.

[0047] Preferably, the pressing element comprises a surface with a concave contour for contacting the receiving part surface.

[0048] Due to this feature, the holding stability of the receiving part between the pairs of pressure elements of the deformation device is improved.

[0049] In a preferred embodiment, the deformation device is designed in such a way that, when the receiving part is actuated along the actuation path, the deformation device exerts a deformation effect on the respective receiving part associated with the deformation device.

[0050] In this way, the time required for the step of testing the tightness can substantially occupy at least a portion of the time required to complete a production cycle of the capsule.

[0051] In a preferred embodiment, each pressing element of a pair of pressing elements associated with a corresponding receiving member is configured to apply a deformation action including a corresponding extrusion, and the two extrusion actions applied by the pair of pressing elements are performed on the receiving member in a substantially simultaneous manner on two corresponding sides of the receiving member that are diametrically opposite to each other.

[0052] Preferably, the container closed by the membrane is a capsule for containing powder for brewing a beverage, and more preferably, the powder for brewing a beverage is coffee powder.

[0053] It should be noted that some steps of the above method may be independent of the execution order described. In addition, some steps may be optional. In addition, some steps of the method may be repeated, or some steps of the method may be performed in series or in parallel with other steps of the method.

[0054] The characteristics and advantages of the present solution will become more apparent from the detailed description of an embodiment of the present solution illustrated by way of non-limiting example with reference to the accompanying drawings, in which:

[0055] - Figure 1 is a schematic perspective view of a device according to the invention for testing the tightness of a container closed by a membrane.

[0056] - Figure 2 yes Figure 1 A schematic diagram of a side elevation and a partial cross section of the device;

[0057] - Figure 3 and Figure 4 is a schematic, partial, enlarged view of a detail of the device in the previous figures.

[0058] With reference to the cited figures, 100 denotes in its entirety a device for testing the leaktightness of a container 1 closed by a membrane 2 , made according to the invention.

[0059] In this preferred embodiment, the container 1 is configured to form a capsule for brewing a product, such as coffee powder, and for this purpose, the container 1 is formed in the form of a truncated cone glass having a cavity with a larger portion facing upwards, where an opening 3 is provided that communicates with the cavity of the container 1. The loose product is introduced through the opening 3.

[0060] The container 1 is provided with an edge 4 delimiting the opening 3, formed in the form of an annular crown, to which the closing membrane 2 is fixed, for example by gluing or welding or by an operation comprising both.

[0061] The membrane 2 is fixed to obtain a gas-tight closure of the container 1 , allowing the contents of the capsule, and the inert protective atmosphere possibly introduced inside the capsule, to remain permanently separated from the external atmosphere, preferably until the step of using the capsule.

[0062] The device 100 includes a conveying device 10, which is formed as a conveyor belt and is configured to manipulate a plurality of containers 1 along a conveying direction F from an entry area, in which the plurality of containers 1 are placed on the conveyor belt by a supply device (not depicted), to an exit area, in which the containers 1 that have completed the step of testing the sealing are picked up and taken to a subsequent processing step of the capsule production cycle.

[0063] In this preferred example, the containers 1 are handled by the conveyor 10 in two rows arranged side by side, each row including a plurality of containers 1 aligned at regular intervals along the conveying direction F, and in this example, each row is linear. The containers 1 are conveyed in a manner that their respective bottoms are placed on the conveyor 10, and their respective bottoms are placed on the portion opposite to the film 2 in the vertical direction.

[0064] The device 100 further comprises a deformation unit 15 which is configured to apply a deformation action to a plurality of containers 1 and which is suitable for testing the tightness.

[0065] The deformation unit 15 comprises a plurality of deformation devices, all of which are denoted by 20 , wherein each deformation device 20 is individually associated with a single corresponding receiving element 1 in order to exert a deformation effect.

[0066] Each deformation device 20 is mounted on the transport device 10 and comprises a plurality of pairs of pressure elements 21 between which the respective receiving element 1 remains positioned during handling of the receiving element 1 on the transport device 10 .

[0067] Each pair of pressing elements 21 is mounted in an articulated manner on a respective support 22 integral with the conveying plane of the conveying device 10. By being mounted in an articulated manner about a respective swing axis directed perpendicularly to the conveying direction F, each pressing element 21 can be swung away from or into an operating position in which it is displaced to exert a deforming action by local squeezing of the receiving element 1. More specifically, each receiving element 1 is subjected to a squeezing action consisting of two squeezing actions performed in a substantially simultaneous manner by the respective squeezing element 21 on two diametrically opposite sides of the receiving element 1.

[0068] In order to control the pivoting movement of the pressure element 21 , a control device 25 is provided which comprises a cam mechanism which comprises a cam follower element 26 which is coupled to a cam contour 27 .

[0069] The cam profile 27 is mounted on a fixed frame 28 which supports the conveyor 10 .

[0070] In more detail, the cam-follower element 26 is formed by a respective roller which is supported on the corresponding pressing element 21 in a rotatable manner about an axis of rotation directed perpendicularly to the conveying direction F, and a cam profile 27 is defined on a track extending longitudinally in the conveying direction F, to which the cam-follower roller 26 is surface-coupled. In this way, by a suitable configuration of the cam profile 27, for example a cam profile 27 comprising parallel sections inclined with respect to the conveying direction F, the cam-follower roller 26 is displaced transversely with respect to the conveying direction F, and by providing a suitable lever arm between the articulation axis of the cam-follower roller 26 and the articulation axis of the pressing element 21, this movement generates a swinging motion of the pressing element 21 out of and towards the operating position during the manipulation of the container 1 in the conveying direction F.

[0071] In each container 1 subjected to deformation, the pair of pressing elements 21 swings around the corresponding swing axis in opposite directions. By swinging toward the operating position, each pressing element 21 applies corresponding compression to the corresponding container 1, and the two compression effects are applied to the corresponding two diametrically opposite sides of the container 1 in a substantially simultaneous manner.

[0072] Reference numeral 21 a denotes a surface of the corresponding pressing element 21 having a concave contour, which is used for surface contact with the receiving part 1 .

[0073] Reference Figure 3 Since in this preferred example the manipulation of two rows of receptacles 1 arranged side by side is provided, the pressure element 21 is controlled in a structurally and functionally effective manner in the following way.

[0074] Each pair of receiving members 1 comprises a first receiving member and a second receiving member which are moved side by side along the conveying direction F and are subjected to the deformation action of the first pair of pressing elements 21 and the second pair of pressing elements 21 .

[0075] The first pair of pressing elements 21 acts on the first receiving member, and the second pair of pressing elements 21 acts on the second receiving member. One pressing element of the first pair of pressing elements 21 and one pressing element of the second pair of pressing elements 21, which are positioned on the same side of the paired receiving members 1 so as to be arranged side by side with each other, can swing integrally with each other around a common swing axis, and the control of such swinging is carried out by a cam-follower roller 26, which is coupled to the track of a cam profile 27 positioned on one side of the conveyor 10.

[0076] Similarly, another pressing element in the first pair of pressing elements 21 and another pressing element in the second pair of pressing elements 21 are also arranged side by side with each other and can swing integrally with each other around the corresponding common swing axis, and the control of such swing is carried out by the corresponding cam-follower roller 26, which is connected to the second track of the cam profile member 27 positioned on the opposite side of the conveying device 10.

[0077] In other words, on this opposite side of the conveying device 10 , the second track of the cam profile 27 to which the corresponding cam-follower roller 26 is coupled is arranged in a mirror-image manner.

[0078] However, it should be noted that, based on this configuration, each pair of pressing elements 21 is configured to act on a single receiving part 1 .

[0079] Furthermore, each pair of containers 1 moving side by side in the conveying direction F is subjected to the action of a corresponding pair of deformation devices 20 , the control of which, by means of a cam mechanism, is common to each other.

[0080] It should also be noted that, through the cam profile 27 shared by all deformation devices 20, the same swinging movement of the pressing element 21 away from the operating position and toward the operating position can be applied in each deformation device 20, and in the operating position, a deformation effect is applied to the corresponding receiving member 1, thereby ensuring the uniformity of the deformation force applied to the receiving member 1.

[0081] 30 denotes a device for manipulating a plurality of abutment elements 31 , each of which is configured to exert an abutment action on the membrane 2 of the corresponding container 1 , thereby counteracting deformation of the membrane 2 caused by the deformation action generated by the compression exerted by the pressing element 21 .

[0082] The manipulator 30 is placed in a position above the conveyor 10, and is constructed as a closed endless belt between a pair of return wheels 32, on which abutment elements 31 aligned at regular intervals are mounted along a moving direction parallel to the conveying direction F. In the manipulator 30, an active branch 30a is defined (identified) between the return wheels 32 having a predetermined interval, and the active branch 30a is rotated to be in a position facing the receiving member 1, so that the abutment element 31 can apply an abutment action to the film 2 during the conveyance of the abutment element 31 along the active branch 30a.

[0083] Downstream of the manipulator 30 relative to the conveying direction F, the apparatus comprises a detection unit 40, which is configured to detect at least one parameter related to the contour portion of the membrane 2, in particular, the detection unit 40 is configured to detect at least one parameter related to the contour portion of the membrane 2 when the abutment applied by the abutment element 31 has stopped.

[0084] Conveniently, the detection unit 40 comprises at least one optical device 41 for contactless measurement of the film 2 .

[0085] Examples of the optical device may include a photoelectric sensor, and in particular, examples of the optical device may include an analog laser sensor.

[0086] The optical device 41 is arranged to detect the contour of the film 2, for example comprising a series of points of the surface of the film 2, during the transport of the containers 1 with a predetermined sampling frequency of the readings performed. It is also provided that for each row of containers 1 a respective sensor is provided.

[0087] In a further embodiment, it can be provided that the optical device comprises a video camera or a camera which is configured to detect the contour of the film 2 by analyzing the image acquired by the optical device 41 .

[0088] The device 100 also includes Figure 2 Schematically shown in FIG. 1 is a control unit 50 configured to compare a parameter related to the profile of the membrane 2 with a predetermined threshold value in order to verify whether the tightness of the container should be classified as defective.

Claims

1. A device for testing the tightness of a container (1) closed by a corresponding membrane (2), comprising: - a deformation unit (15), the deformation unit (15) being configured to exert a deformation effect on a plurality of the receiving elements (1); as well as a detection unit (40) for detecting the deformation of the membrane (2) of each container (1) subjected to the deformation; The deformation unit (15) comprises a plurality of deformation devices (20), and each deformation device (20) is individually associated with a single corresponding container (1) among the plurality of containers to apply the deformation effect.

2. The device according to claim 1, further comprising a conveying device (10) for conveying a plurality of the containers (1) toward the detection unit (40), wherein: A plurality of the deformation devices (20) are mounted on the conveying device (10).

3. The device according to claim 1 or 2, wherein: Each deformation device (20) comprises a pair of pressing elements (21), between which the corresponding container (1) can be positioned, and the pressing elements (21) are hingedly mounted on the corresponding support (22) so that the pressing elements (21) undergo displacement movement away from and toward an operating position, in which the pressing elements (21) exert an action that causes the corresponding container (1) to deform.

4. The device according to claim 3, wherein: The displacement movement of the pressing element (21) away from the operating position and towards the operating position is a swiveling movement.

5. The device according to claim 3 or 4 comprises a control device (25) for controlling the displacement movement of each pressing element (21), the control device comprising a cam mechanism, the cam mechanism comprising a corresponding cam-follower element (26) supported in a rotatable manner on each pressing element (21), and the cam-follower element (26) is connected to the surface of a cam profile member (27) shared by multiple deformation devices (20).

6. The device according to claim 5, wherein: The cam profile (27) is mounted on a fixed frame (28) supporting the conveying device (10).

7. An apparatus according to claim 5 or 6, comprising a pair of cam profiles (27), which are respectively arranged at opposite sides of the conveying device (10) in the transverse direction relative to the longitudinal extension direction of the conveying device (10).

8. The device according to one of claims 3 to 7, wherein The pressing element (21) comprises a surface (21a) having a concave contour portion, and the surface (21a) having a concave contour portion is used for surface contact with the receiving member (1).

9. The device according to one or more of the preceding claims, wherein: The deformation device (20) is configured such that when the receiving part (1) is manipulated along the manipulation path, the deformation device (20) exerts the deformation effect on the corresponding receiving part (1) associated with the deformation device (20).

10. The device according to one or more of claims 3 to 9, wherein: Each pressing element (21) in the pair of pressing elements associated with the corresponding container (1) is configured to apply a deformation effect including corresponding extrusion, and the two extrusion effects applied by the pair of pressing elements (21) are performed on the container in a substantially simultaneous manner on two corresponding diametrically opposite sides of the container (1).

11. A method for testing the tightness of a container (1) closed by a corresponding membrane (2), the method comprising the following steps: A deformation unit (15) is provided, comprising a plurality of deformation devices (20), wherein the deformation devices (20) are configured to exert a deformation effect on a corresponding plurality of the receiving members (1), A detection unit (40) is provided, wherein the detection unit (40) is used to detect the deformation of the membrane (2) of each container (1) subjected to the deformation effect; Associating each deformation device (20) individually with a single corresponding container (1) of the plurality of containers to apply the deformation effect; The deformation of the membrane (2) of each container (1) subjected to the deformation is detected to test the sealing performance of the container (1).

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