Sealing device for packaging machine, packaging machine having sealing device, and method of operating sealing device

Abstract

A sealing apparatus (20) for sealing packages (2) filled with a pourable product in a packaging machine (1) is described. The sealing apparatus (20) comprises at least one sonotrode (21), the sonotrode comprising a sonotrode head (23) and a vibration control unit (25) connected to the sonotrode head (23) and configured to activate ultrasonic vibrations of the sonotrode head (23). The vibration control unit (25) comprises one or more piezoelectric transducer devices (30) configured to generate ultrasonic vibrations that are coupled to the sonotrode head (23) and a sensor device (34) configured to measure one or more time-dependent electrical parameters of each of the one or more piezoelectric transducer devices (30) during use.

Description

[Technical field]

[0001] The present invention relates to a sealing device for sealing, in particular transversely sealing, packages, in particular composite packages, in a packaging machine for packaging pourable products, in particular pourable food products.

[0002] Advantageously, the invention also relates to a packaging machine for packaging pourable products, in particular pourable food products, in packages, in particular composite packages, comprising at least one sealing device for sealing the packages.

[0003] Furthermore, the invention also relates to a method of operating a sealing device in a packaging machine for packaging pourable products, in particular pourable food products, in packages, in particular composite packages. [Background technology]

[0004] As is well known, many liquid or pourable food products, such as fruit juice, UHT (ultra-high temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material, in particular in sealed packages.

[0005] A typical example is the parallelepiped package for pourable food products known as Tetra Brik Aseptic®, which is made by sealing and folding a laminated strip of packaging material. The packaging material has a multi-layer structure including a base layer of carton and / or paper, covered on both sides with a layer of heat-sealable plastic material, e.g., polyethylene. In the case of aseptic packaging for shelf-stable products, the packaging material includes a layer of oxygen barrier material, e.g., aluminum foil, which overlaps with a layer of heat-sealable plastic material and is covered with another layer of heat-sealable plastic material to form the inner surface of the package that ultimately contacts the food product.

[0006] This type of package is typically produced by a fully automatic packaging machine which, in use, advances a web of packaging material through a sterilization unit of the packaging machine to sterilize the web of packaging material. The sterilized web of packaging material is then maintained in an isolation chamber and advanced, longitudinally folded and sealed to form a tube, which is advanced further. The tube is further filled with pourable product, transversely sealed, and cut along equally spaced transverse cross sections within a package forming apparatus of the packaging machine during the advancement of the tube.

[0007] More specifically, the package forming apparatus comprises a plurality of forming and sealing assemblies, each of which, in use, forms, transversely seals and cuts a tube to obtain a single package.

[0008] Each form-and-seal assembly comprises a respective sealing device for transversely sealing the tube by locally compressing the tube and heating a respective portion of the layer of heat-sealable plastic material to obtain a respective transverse seal portion, the heating being carried out, for example, by the sealing device generating ultrasonic vibrations.

[0009] The ultrasonic vibration heating sealing device includes a sonotrode configured to generate ultrasonic vibrations and an anvil designed to cooperate with the sonotrode to locally compress the tube.

[0010] A typical sonotrode comprises a sonotrode head having a sealing surface extending along a longitudinal axis, and a vibration control unit connected to the sonotrode head and configured to activate ultrasonic vibrations of the sonotrode head.

[0011] More specifically, the vibration control unit comprises a housing shell and one or more piezoelectric transducers disposed within the housing shell and configured to generate ultrasonic vibrations coupled to the sonotrode head.

[0012] Although known sealing devices operate with high quality and reliability, there is a desire in the art to further improve upon known sealing devices.

[0013] In particular, there is a desire to control the sealing process as much as possible.

[0014] In particular, there is a desire to extend the life of each sonotrode as much as possible and to avoid undesirable breakdowns. Summary of the Invention [Problem to be solved by the invention]

[0015] SUMMARY OF THE PRESENT EMBODIMENT It is therefore an object of the present invention to provide an improved sealing arrangement which is simple and low cost.

[0016] It is a further object of the present invention to provide a packaging machine having an improved sealing device which is simple and low cost.

[0017] It is a further object of the present invention to provide a method of operating the improved sealing device in a simple and cost-effective manner.

[0018] According to the invention there is provided a sealing device as claimed in independent claim 1.

[0019] Preferred embodiments of the sealing device are set out in the claims which depend directly or indirectly on claim 1.

[0020] According to the invention there is also provided a packaging machine as claimed in claim 11.

[0021] Furthermore, the present invention also provides a method according to claim 12.

[0022] Preferred embodiments of the method are set out in the claims which depend directly or indirectly on claim 12. [Means for solving the problem]

[0023] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. [Brief description of the drawings]

[0024] [Figure 1] 1 is a schematic diagram, with parts removed for clarity, of a packaging machine having at least one sealing device according to the invention; [Diagram 2] FIG. 2 is a schematic view, with parts removed for clarity, of a detail of the packaging machine of FIG. 1 forming part of a sealing device according to the invention; [Diagram 3] FIG. 3 is a side view of a portion of the sealing device of FIG. 2 with parts removed for clarity. [Figure 4] 4A and 4B show respective time-dependent curves of electrical parameters measured with a sensor device of a sealing device and a time-dependent drive signal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Number 1 indicates as a whole a packaging machine for producing packages 2, in particular sealed packages 2, of pourable products, in particular pourable food products, such as (pasteurized) milk, fruit juice, wine, tomato sauce, salt, sugar, etc.

[0026] More particularly, the packaging machine 1 may be configured to produce packages 2 from a multi-layer packaging material.

[0027] More specifically, the multi-layer packaging material may comprise at least one layer of fibrous material, e.g. paper or cardboard, and at least two layers of heat-sealable plastic material, e.g. polyethylene, sandwiching the layers of fibrous material between each other, with one of the two layers of heat-sealable plastic material defining the inner surface of the package 2 in contact with the pourable product.

[0028] Furthermore, the packaging material may comprise a layer of gas- and light-barrier material, such as an aluminum foil or an ethylene vinyl alcohol (EVOH) film, in particular arranged between one of the layers of heat-sealable plastic material and the layer of fibrous material. Preferably, the packaging material may comprise a further layer of heat-sealable plastic material, interposed between the layer of gas- and light-barrier material and the layer of fibrous material.

[0029] In particular, the web 3 comprises a plurality of repeating patterns, each pattern defining a respective blank for forming one of the packages 2 .

[0030] Further, the packaging machine 1 may be configured to produce the package 2 by forming a tube 4 from the web 3, sealing the tube 4 longitudinally, filling the tube 4 with a pourable product, and sealing and cutting the tube 4 transversely.

[0031] A typical package 2 obtained by the packaging machine 1 comprises a longitudinal seam 5 and in particular a pair of respective first and respective second transverse seal bands arranged on opposite sides of the package 2. In particular, the first transverse seal band may define a top transverse seal band and the second transverse seal band may define a bottom transverse seal band.

[0032] With particular reference to FIG. 1, the packaging machine 1 comprises: - a conveying device 7 for advancing the web 3 (in a known manner) along a web advancement path P to a forming station 8; an isolation chamber 9 having an internal environment, in particular an internal sterile environment containing a sterile gas, separated from the (hostile) external environment; - a tube forming and sealing device 10 configured, in use, to form a tube 4 from an advancing web 3 within an internal environment and to longitudinally seal the tube 4 within the internal environment; - a filling device 11 for continuously filling the tubes 4 with pourable product, - a package forming device 12 configured to form, transversely seal and transversely cut an advancement tube 4 for forming a package 2; The present invention may also include:

[0033] Furthermore, the packaging machine 1 may be provided with a sterilization unit configured to sterilize the advancing web 3, in use, at a sterilization station, in particular the sterilization station being arranged along the web advancement path P upstream of the forming station 8.

[0034] More specifically, the conveying device 7 may be configured to advance the tube 4 and any intermediate part of the tube 4 along the tube advancement path Q, in particular from the forming station 9 to the package forming device 16. In particular, under intermediate part of the tube 4 is meant any configuration of the web 3 before obtaining the tube structure and after folding of the web 3 by the tube forming and sealing device 10 has started. In other words, the intermediate part of the tube 4 is the result of a gradual folding of the web 3 to obtain the tube 4, in particular by overlapping the ends of the web 3 on top of each other.

[0035] Preferably, the tube forming and sealing apparatus 10 may be arranged so that the tube 4 is oriented vertically.

[0036] More specifically, the tube forming and sealing device 10 may comprise at least two forming ring assemblies 16, particularly located within the isolation chamber 9, adapted to cooperate with one another to gradually fold the web 3 into the tube 4, particularly by overlapping the edges of the web 3 with one another, thereby forming the seam 5 of the tube 3, in use.

[0037] Furthermore, the tube forming and sealing device 10 may comprise a sealing head 17 , particularly arranged within the isolation chamber 9 , configured to longitudinally seal the tube 4 , particularly along the seam 5 .

[0038] Additionally, the tube forming and sealing device 10 may include a pressure assembly configured to exert a mechanical force on the seam 5 to ensure sealing of the tube 4 along the seam 5 .

[0039] Furthermore, the filling device 11 may comprise a filling pipe 18 configured to, in use, guide the pourable product into the tube 4. In particular, the filling pipe 18 may be arranged at least partially within the tube 4 so as to, in use, supply the pourable product into the tube 4.

[0040] Referring to FIGS. 1 and 2, the package forming apparatus 12 includes: - forming and sealing assemblies 19 (only partially shown in FIG. 2 to the extent necessary for the understanding of the invention), each of which is adapted to at least form the tube 4, to laterally seal the tube 4 and in particular also to laterally cut the tube 4; a transport unit (not shown, as it is well known) for advancing the forming and sealing assemblies 19; The present invention may also include:

[0041] In particular, the package forming apparatus 12 may be configured to control the form and seal assembly 19 and the transfer units to laterally seal and cut the tube 4 along equally spaced cross sections. More particularly, the package forming apparatus 12 may be configured to control the form and seal assembly 19 and the transfer units to laterally seal and cut the tube 4 according to a repeating pattern.

[0042] More specifically, each molded and sealed assembly 19 includes: - a molded shell (not shown, as it is well known) configured to at least partially define the shape of the package 2; a sealing device 20 adapted to at least laterally compress, in particular to flatten and laterally seal, the tube 4; The present invention may also include:

[0043] Additionally, each form and seal assembly 19 may include a cutting device (not shown) for cutting the tube 4 transversely.

[0044] Preferably, each sealing device 20 is configured to form a main seal strip, and in particular each cutting device is configured to cut the main seal strip transversely. More preferably, each main seal strip joins a first transverse seal strip of a respective preceding package 2 with a second transverse seal strip of a respective succeeding package 2.

[0045] More particularly, each molded shell may comprise at least a first half shell (not shown, as it is known per se) and a second half shell (not shown, as it is known per se) configured to cooperate to at least partially define the shape of the package 2. In particular, the first half shell and the second half shell may be configured to contact the tube 4 from opposite sides thereof.

[0046] More particularly, each sealing device 20 may be of the ultrasonic type, i.e. configured to generate ultrasonic vibrations suitable for heating a portion of the layer of heat-sealable plastic material.

[0047] Further, each sealing device 20 includes at least - a sonotrode 21 for generating ultrasonic vibrations, in particular for heating / melting respective portions of the layer of heat-sealing plastic material; - an anvil 22 for compressing, in particular locally flattening and squeezing, the tube 4 in cooperation with the sonotrode 21; Equipped with.

[0048] More specifically, each cutting device may comprise at least one movable blade to cut the tube 4 transversely.

[0049] Further, each sonotrode 21 may be associated with a respective first half shell, in particular defining a first operative portion of each forming and sealing assembly 19, and each anvil 22 may be associated with a respective second half shell, in particular defining a second operative portion of each forming and sealing assembly 19.

[0050] Furthermore, a respective blade of a respective cutting device may be associated with a respective sonotrode 21 or with a respective anvil 22, in a specific case with a respective anvil 22. In other words, each cutting device may be associated with a respective first operating part or with a respective second operating part, in a specific case with a respective second operating part.

[0051] Further, the transport unit may be configured to advance each first working portion along a first path and to advance each second working portion along a second path.

[0052] Further, each first operating portion and each second operating portion may be configured to cooperate with each other to form the package 2 as they advance along the respective operating portions of the first path and the second path, respectively.

[0053] 2 and 3, each sonotrode 21 comprises at least: a sonotrode head 23 having a sealing surface 24 extending in particular along the longitudinal axis A; a vibration control unit 25 connected to the sonotrode head 23 and configured to activate the ultrasonic vibrations of the sonotrode head 23; Equipped with.

[0054] More specifically, each sealing surface 24 may be designed to contact the tube 4 and establish an operative connection with a portion of the layer of heat seal plastic.

[0055] Additionally, each sealing surface 24 may include a first portion and a second portion that are offset and parallel to one another.

[0056] Furthermore, each sonotrode head 23 may in particular include a groove 26 interposed between the respective first portion and the respective second portion. In particular, each groove 26 may be designed to receive a portion of a respective blade when cutting the tube 4 transversely.

[0057] Returning to Fig. 3, each vibration control unit 25 may comprise one or more piezoelectric transducer devices 30 configured to generate ultrasonic vibrations that are coupled to the respective sonotrode head 23. In the illustrated embodiment, the vibration control unit 25 comprises three piezoelectric transducer devices 30, but the number may vary depending on the type of package 2 and / or the dimensions of the sealing surface. That is, depending on the type of package 2, the sealing surface 24 may have a greater or lesser extension. In particular, if the sealing surface 24 is short, fewer piezoelectric transducer devices 30 may be required than if the sealing surface is large.

[0058] 3, each piezoelectric transducer device 30 may comprise a number of piezoelectric (ceramic) elements 31 stacked one on top of the other. More particularly, each piezoelectric transducer device 30 may comprise a number of conductive metal sheets, in particular forming, together with the piezoelectric elements 31, a stack of alternating piezoelectric elements 31 and conductive metal sheets.

[0059] Furthermore, each sealing device 20, and in particular each vibration control unit 25, may comprise one or more generators 32 operably connected to the piezoelectric transducer 30, and in particular the piezoelectric element 31, so as to activate and control the ultrasonic vibrations of the piezoelectric transducer 30.

[0060] In particular, each generator 32 may be configured to introduce a drive signal to a respective piezoelectric transducer 30 , in particular to a respective stack of piezoelectric elements 31 .

[0061] More particularly, and with reference to Figure 4, such a drive signal may be an alternating voltage signal 33 (see, for example, Figure 4). In particular, according to such an embodiment, the piezoelectric transducers 30 may be arranged electrically in parallel.

[0062] Alternatively, the piezoelectric vibrators 30 may be electrically arranged in series, and the drive signal may be an AC signal.

[0063] Advantageously, each sealing device 20 comprises a sensor device 34 configured to measure, in use, one or more time-dependent electrical parameters or quantities of at least one of the one or more piezoelectric transducer devices 30, for example each one, in particular each stack of piezoelectric elements 31. For example, the electrical parameters or quantities may be measured at each piezoelectric transducer 30 after the drive signal has been subdivided for the different piezoelectric transducers 30. The measurements may be performed for one or more or all piezoelectric transducers 30.

[0064] In particular, each sensor device 34 is configured to obtain real-time measurements of one or more time-dependent electrical parameters.

[0065] Examples of time-dependent electrical parameters or quantities include current, voltage, and power.

[0066] More specifically, each sensor device 34 may be configured to selectively determine a time-dependent electrical parameter of one or more piezoelectric transducer devices 30, in particular of each respective stack of piezoelectric elements 31, independently from other respective stacks of piezoelectric elements 31.

[0067] Preferentially, each sensor device 34 may be configured to determine a respective time-dependent curve of one or more electrical parameters of a respective one of the one or more piezoelectric transducer devices 30, in particular of each stack of piezoelectric elements 31.

[0068] Referring to FIG. 4, each sensor device 34 may be configured to determine a first time-dependent curve 35 associated with a first piezoelectric transducer device 30 of the three piezoelectric transducer devices 30, a second time-dependent curve 36 associated with a second piezoelectric transducer device 30 of the three piezoelectric transducer devices 30, and a third time-dependent curve 37 associated with a third piezoelectric transducer device 30 of the three piezoelectric transducer devices 30.

[0069] Furthermore, the first time dependent curve 35, the second time dependent curve 36 and the third time dependent curve 37 may represent electrical parameters or quantities. For example, according to the illustrated embodiment, the first, second and third time dependent curves 35, 36, 37 represent respective time dependent currents flowing in the respective piezoelectric transducer device 30, in particular in the respective stacks of piezoelectric elements 31.

[0070] Alternatively, other electrical parameters may be determined and their time-dependence curves measured in a similar manner.

[0071] According to some non-limiting embodiments, each sensor device 34 may be configured to measure a respective time dependence curve for one or more electrical parameters of each piezoelectric transducer device 30, in particular each stack of piezoelectric elements 31.

[0072] Preferably, each sealing device 20, in particular each sensor device 34, may be provided with a memory adapted to store, in particular at least temporarily store, the electrical parameter and / or the respective time-dependent curve.

[0073] More specifically, each sealing device 20 may be operatively connected, directly or indirectly, for example wirelessly, to the respective sensor device 34 and may comprise an analysis unit 38 configured to receive and analyze the time-dependent electrical parameters, in particular the respective time-dependent curves.

[0074] More specifically, each analysis unit 38 has the following configuration: - determining characteristic parameters or features from the one or more time-dependent curves; - inferring characteristic parameters or characteristics from one or more time-dependent curves and comparing the characteristic parameters or characteristics with reference parameters or characteristics; and / or - comparing one or more of the time-dependent curves with a reference curve; and / or - Analyzing the shape of each of the time-dependent curves.

[0075] The characteristic parameters or properties may comprise one or more root mean square values ​​of time dependent curves, frequency, power, instantaneous power, phase shift between current and voltage, and / or dissipated power.

[0076] In one or more embodiments, the sonotrode may be represented by an (equivalent) electric circuit consisting of the capacitance, the equivalent resistance, the equivalent inductance and the equivalent capacitance of the stack of piezoelectric elements 31. That is, the sonotrode circuit may be approximated using the equivalent electric circuit described above. The analysis unit 38 may be configured to calculate the capacitance, the equivalent resistance, the equivalent inductance and the equivalent capacitance of the stack of piezoelectric elements 31 as a function of characteristic parameters or features of the time-dependent curve.

[0077] Alternatively or additionally, each analysis unit 38 may be configured to determine from the determined electrical parameters, in particular the respective time-dependent curves, information, such as quality information, relating to the lateral sealing process of the respective sealing device 20. For example, each analysis unit 38 may use such information to assess the quality of the respective lateral sealing process and / or to determine the pressure acting on various portions of the respective main sealing strip.

[0078] According to some non-limiting embodiments, each analysis unit 38 may be configured to selectively determine a respective operating state of one or more piezoelectric transducer devices 30, in particular a respective stack of piezoelectric elements 31, depending on the respective electrical parameters, in particular the respective time-dependent curves, determined by the respective sensor devices 34.

[0079] Preferably, each sealing device 20 may be provided with a temperature detection device configured to determine the temperature, in particular the time-dependent temperature profile, of each of the one or more piezoelectric transducer devices 30, in particular each stack of piezoelectric elements 31.

[0080] Advantageously, each analysis unit 38 may be configured to selectively determine the operating state of each of the one or more piezoelectric transducer devices 30 depending on the respective electrical parameters determined by the respective sensor devices 34, in particular the respective time-dependent curves, and the respective temperatures determined by the respective temperature detection devices, in particular the respective time-dependent temperature profiles.

[0081] Preferentially, the operating state of each piezoelectric transducer device 30, in particular each stack of piezoelectric elements 31, may provide information regarding the aging and / or health state and / or remaining life of each piezoelectric transducer device 30, in particular each stack of piezoelectric elements 31.

[0082] According to some non-limiting embodiments, each analysis unit 38 and / or processing unit of the sealing device 20 and / or packaging machine 1 may be configured to plan maintenance activities based on the respective operating state of the piezoelectric transducer device 30. In particular, the analysis unit 38 and / or processing unit may be configured to plan maintenance activities as a function of the remaining life and / or aging and / or health of the piezoelectric transducer device 30. In this way, it is possible to optimize the use of the piezoelectric transducer device 30.

[0083] Preferentially, each analysis unit 38 and / or processing unit may be configured to signal (directly or indirectly) the remaining life of the piezoelectric transducer device 30 and to signal that maintenance should be performed within a certain time window.

[0084] Alternatively or additionally, each analysis unit 38 and / or processing unit may be configured to assess, depending on the respective electrical parameters, in particular the respective time-dependent curves, the possible occurrence of an abnormal operating state of one or more piezoelectric transducer devices 30. Furthermore, each analysis unit 38 and / or processing unit may be configured to warn about the risk of an abnormal operating state, for example by means of a prompt on a human-machine interface (of the packaging machine 1), and / or an acoustic message, and / or an electronic message.

[0085] 3, each sensor device 34 may comprise one or more sensor elements 39, each associated with one respective piezoelectric transducer arrangement 30, in particular a respective stack of piezoelectric elements, for measuring one or more time-dependent electrical parameters of the respective piezoelectric transducer arrangement 30. For example, each sensor device 34 may comprise a plurality of sensor elements 39, which may be associated with a respective plurality of stacks of piezoelectric elements.

[0086] Preferably, each sensor element 39 may comprise at least one Hall effect sensor and / or at least one Shunt sensor.

[0087] According to some non-limiting embodiments, the sensor device 34 may comprise one or more measurement circuits, including in particular portions for signal amplification and / or signal filtering.

[0088] One or more measurement circuits may comprise the sensor element 39 or may be connected to the sensor element 39 .

[0089] According to some preferred, non-limiting embodiments, each sensor device 34 may comprise a substrate carrying a respective sensor element 39 and in particular a respective measurement circuit.

[0090] According to some non-limiting embodiments, each analysis unit 38 may be disposed on a respective substrate of a respective sensor device 34 .

[0091] Alternatively or additionally, each sensor device 34 may comprise a communication group operatively coupled to a respective analysis unit 38 for transferring the respective electrical parameters, in particular the time-dependent curves.

[0092] Furthermore, each communication group may be configured to communicate with a respective analysis unit 38 via hardwire and / or wireless communication.

[0093] According to some possible embodiments, each analysis unit 38 may be spaced apart from its respective sensor device 34 and / or may be part of and / or integrated into a central analysis unit of the package forming device 12 and / or packaging machine 1.

[0094] 2 and 3, the vibration control unit 25 may further include at least a housing shell 41 having an interior space 41 .

[0095] Further, each vibration control unit 25 may comprise at least a housing shell 41 (shown in FIG. 2, the transparent representation being for illustrative purposes) having an interior space 41, in particular the housing shell 41 being in contact with the respective sonotrode head 23 so as to seal the interior space 41 from the exterior space.

[0096] Preferably, each piezoelectric transducer device 30 and each sensor device 34 is arranged in a respective interior space 41, i.e. surrounded by a respective housing 40. In particular, a respective substrate of each sensor device 34 may be arranged in a respective interior space 41. Such a solution allows for a compact construction.

[0097] In particular, each generator 32 may also be disposed within a respective interior space 41 .

[0098] More specifically, each housing 40 may include a main wall 42 , a side wall 43 extending from the main wall 42 , and an opening opposite the main wall 42 .

[0099] Furthermore, each vibration control unit 25 may comprise a coupling part 44 which contacts the respective sonotrode head 23 along a respective contact surface. Furthermore, each piezoelectric transducer device 30 may be disposed in a respective seat 45 (see in particular FIG. 2 ) of the respective coupling part 44 and in contact with the respective coupling part 44 so as to be able to transmit the generated ultrasonic vibrations to the respective sonotrode head 23.

[0100] In particular, the respective opening of each housing 40 may be designed to allow the respective coupling portion 44 to be introduced into the interior space 41 .

[0101] Further, each sensor device 34 may be disposed within a portion of the respective interior space 41 that is interposed between the respective coupling portion 44 and the main wall 42. For example, each substrate may be attached to the respective main wall 42.

[0102] In use, the packaging machine 1 produces packages 2 filled with a pourable product.

[0103] More specifically, a conveying device 7 advances the web 3 along a web advancement path P to a forming station 8. A tube forming and sealing device 10 forms a tube 4 from the advancing web 3 and longitudinally seals the tube 4. Further, a filling device 11 fills the tube 4 with a pourable product, and a package forming device 12 forms, transversely seals and transversely cuts the tube 4 into packages 2.

[0104] More specifically, during operation of the package-forming unit 12 , the form-and-seal assembly 19 forms, transversely seals and in particular transversely cuts the tube 4 to obtain the respective filled package 2 .

[0105] Thereby, shaping takes place by the respective shaping shells, in particular by the respective first and second half shells cooperating with one another.

[0106] Further, lateral sealing is provided by respective sealing devices 20 .

[0107] Furthermore, the transverse cuts are carried out by respective cutting devices.

[0108] More specifically, the operation of each sealing device 20 includes at least the following steps: - compressing, in particular flattening and squeezing, the tube 4 by the cooperation of the respective anvil 22 and the respective sonotrode 21; - generating ultrasonic vibrations by a sonotrode 21 to heat a portion of the heat seal resin layer; Equipped with.

[0109] More specifically, the operation of each sealing device 20 further comprises: a) exciting ultrasonic vibrations of each sonotrode head 23 by operating the vibration control unit 25, in particular the respective generators 32, the respective piezoelectric transducers 30; b) measuring one or more time-dependent electrical parameters of one or more piezoelectric transducer devices 30, in particular of at least one of the respective stacks of piezoelectric elements 31, e.g. of each piezoelectric transducer device 30; Equipped with.

[0110] More specifically, during each step b), each sealing device 34 may measure a respective time-dependent electrical parameter, in particular a respective time-dependent curve.

[0111] Preferentially, the operation of each sealing device 20 may comprise a step c) of measuring the temperature of one or more piezoelectric transducers 30, in particular by means of a respective temperature sensing.

[0112] According to a preferred, non-limiting embodiment, the operation of each sealing device 20 may comprise a step d) of analysing the electrical parameters, in particular the time-dependence curves, in particular by means of the respective analysis unit 38 .

[0113] In particular, during step d), each analysis unit 38 - determining one or more characteristic parameters from the one or more time-dependent curves, and / or - estimating one or more characteristic parameters from the one or more time-dependent curves and comparing the characteristic parameters with reference parameters; - calculating the capacitance of the stack of piezoelectric elements 31, the equivalent resistance, the equivalent inductance and the equivalent capacitance of the (equivalent) electric circuit (electrical circuit) representing the sonotrode as a function of one or more characteristic parameters of the time-dependent curve, and / or - comparing one or more of the time-dependent curves with a reference curve; - analyzing the shape of each of the time-dependent curves; determining information regarding the transverse sealing process of each sealing device 20, e.g. quality information, and / or - determining the operating state of one or more piezoelectric transducer devices 30; The present invention may also include:

[0114] Additionally or alternatively, during step d), the remaining life and / or ageing and / or health and / or abnormal operating conditions of one or more piezoelectric transducer devices 30 may be determined.

[0115] According to some possible non-limiting embodiments, during step d), the temperature of the one or more piezoelectric transducer devices 30 may be taken into account.

[0116] Furthermore, the operation of each sealing device 20 may further comprise a transfer step, during which the measurement results from step b), and in particular also from step c), may be transferred to an analysis unit 38 and / or a processing unit.

[0117] Moreover, operation of each sealing device 20 may further include a planning step, in which maintenance is planned based on the operational state of the one or more piezoelectric transducers 30. In particular, in this way, maintenance may be planned based on the useful remaining life and / or aging and / or health state of the respective one or more piezoelectric transducers 30.

[0118] Furthermore, operation of each sealing device 20 may include a warning step during which the risk of an abnormal operating condition may be indicated, for example by a prompt on a human-machine interface, and / or an acoustic message, and / or a similar electronic message.

[0119] The advantages of the sealing device 20 and / or the packaging machine 1 and / or the method according to the invention will be apparent from the above description.

[0120] In particular, each sealing device 20 with a sensor device 34 allows real-time monitoring of the respective sonotrode 21 by monitoring electrical parameters of the piezoelectric transducer device 30 .

[0121] A further advantage is that direct feedback can be obtained from the piezoelectric transducer 30 to monitor the sealing process.

[0122] Another advantage is that the sensor device 34 can be implemented economically.

[0123] Yet another advantage is that the sensor device 34 enables conditioning monitoring and predictive maintenance.

[0124] A further advantage is that data from the sensor device 34 allows for process control.

[0125] However, modifications may be made to the sealing device 20 and / or the packaging machine 1 and / or the method as described herein without departing from the scope of protection defined in the appended claims.

Claims

1. A sealing device (20) for sealing packages (2) filled with a pourable product in a packaging machine (1), comprising: The sealing device (20) comprises at least one sonotrode (21), which sonotrode comprises at least: Sonotrode head (23) and a vibration control unit (25) connected to the sonotrode head (23) and configured to activate ultrasonic vibrations of the sonotrode head (23); Equipped with The vibration control unit (25) one or more piezoelectric transducer devices (30) configured to generate ultrasonic vibrations coupled to the sonotrode head (23); a sensor device (34) configured to measure, during use, one or more time-dependent electrical parameters of at least one piezoelectric transducer device of the one or more piezoelectric transducer devices (30); Equipped with Sealing device (20).

2. the electrical parameter is selected from the group consisting of current, voltage, and / or power; The sealing device according to claim 1 .

3. the sensor device (34) is configured to determine a respective time-dependence curve (33, 35, 36, 37) of one or more electrical parameters of one or more piezoelectric transducer devices (30); The sealing device according to claim 1 .

4. and an analysis unit (38) operatively connected to the sensor device (34) and configured to receive and analyze the time-dependent curve. The sealing device according to claim 3 .

5. The analysis unit (38) determining one or more characteristic parameters from said one or more time-dependent curves (33, 35, 36, 37); - determining one or more characteristic parameters from said one or more time-dependent curves (33, 35, 36, 37) and comparing said determined characteristic parameters with reference parameters; and / or Calculating the capacitance of the stack of piezoelectric elements (31), the equivalent resistance, the equivalent inductance and the equivalent capacitance of the electric circuit representing the sonotrode as a function of one or more characteristic parameters of said time-dependent curves (33, 35, 36, 37), and / or comparing one or more of said time-dependent curves (33, 35, 36, 37) with a reference curve; and / or analyzing the shape of each of said time-dependent curves (33, 35, 36, 37); determining information about the sealing process from said time-dependent curves (33, 35, 36, 37); Equipped with The sealing device according to claim 4.

6. an analysis unit (38) operatively connected to the sensor device (34) and configured to selectively determine an operating state of the one or more piezoelectric transducer devices (30) depending on respective electrical parameters determined by the sensor device (34); The sealing device according to claim 1 .

7. a temperature sensing device configured to determine a temperature of the one or more piezoelectric transducer devices (30); The sealing device according to claim 1 .

8. an analysis unit (38) operatively connected to the sensor device (34) and configured to selectively determine an operating state of the one or more piezoelectric transducer devices (30) depending on the respective electrical parameters determined by the sensor device (34) and the temperature determined by the temperature detection device; The sealing device according to claim 7.

9. The vibration control unit (25) further comprises at least a housing shell (41) having an interior space (41); Each piezoelectric transducer device (30) and the sensor device (34) are disposed within the housing shell (41). The sealing device according to claim 1 .

10. the sensor device (34) has one or more sensor elements (39) each associated with one respective piezoelectric transducer device (30) for measuring one or more time-dependent electrical parameters of the respective piezoelectric transducer device (30), the one or more sensor elements (39) preferably comprising one or more Hall effect sensors and / or shunt sensors; The sealing device according to claim 1 .

11. A packaging machine (1) for pourable products into packages (2), comprising at least one sealing device (20) according to claim 1.

12. A method of operating the sealing device (20) of claim 1, comprising the steps of: The method includes at least a) exciting ultrasonic vibrations in the sonotrode head (23) by operation of one or more piezoelectric transducer devices (30); b) measuring one or more time-dependent electrical parameters of at least one, and preferably each, of one or more piezoelectric transducer devices (30); A method comprising:

13. d) analyzing the electrical parameters. The method of claim 12.

14. During step d), the analysis unit (38) of the sealing device (20) determining one or more characteristic parameters from one or more time-dependent curves of the electrical parameters; and / or estimating one or more characteristic parameters from the one or more time-dependent curves and comparing the characteristic parameters with reference parameters; Calculating the capacitance of the stack of piezoelectric elements (31), the equivalent resistance, the equivalent inductance and the equivalent capacitance of the electric circuit representing the sonotrode as a function of one or more characteristic parameters of the time-dependent curve; and / or comparing one or more of the time-dependent curves to a reference curve; Analyzing the shape of each of the time-dependent curves; determining information, preferably quality information, about the sealing process performed by the sealing device (20) based on one or more time-dependent electrical parameters; and / or determining an operational state of the one or more piezoelectric transducer devices based on the one or more time-dependent electrical parameters; Equipped with The method of claim 13.

15. During step d), the remaining life time and / or aging and / or health and / or abnormal operating conditions of said one or more piezoelectric transducer devices (30) are determined. The method of claim 13.

Images