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 one or more sonotrodes (21), the sonotrode (21) 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 transducing devices (35) configured to generate ultrasonic vibrations coupled to the sonotrode head (23) and one or more temperature sensors (36) configured to measure the temperature of the one or more piezoelectric transducing devices (35) to determine and / or monitor a respective operating condition of the one or more piezoelectric transducing devices (35).

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, especially sealed packages, made of sterile packaging material.

[0005] A typical example is the pourable parallelepiped-shaped package 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 packages for long-term storage products, the packaging material includes a layer of oxygen barrier material, e.g., aluminum foil, which is laminated with a layer of heat-sealable plastic material and covered with another layer of heat-sealable plastic material, finally forming the inner surface of the package that comes into contact with the food.

[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 within an isolation chamber and advanced, longitudinally folded and sealed to form a tube, which is then advanced further. The tube is further filled with the pourable product and 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 includes a plurality of form and seal assemblies, each of which, upon use, forms, transversely seals and cuts a tube to yield 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, which may be performed, for example, by using a 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 transducer devices disposed within the housing shell and configured to generate ultrasonic vibrations coupled to the sonotrode head.

[0012] Piezoelectric transducer devices are known to have a reduced lifespan due to aging and the entire sonotrode or at least the piezoelectric transducer device needs to be replaced according to pre-established maintenance procedures.

[0013] Despite the high quality and reliable operation of known sealing devices, there is a need in the art to further improve upon known sealing devices.

[0014] In particular, there is a desire to make each sonotrode last as long 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 simple and low cost packaging machine having an improved sealing arrangement.

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

[0018] According to the present 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, according to the present invention, there is also provided a method as set forth in 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 diagram, with parts removed for clarity, showing details of the packaging machine of FIG. 1 including part of a sealing device according to the present invention; [Diagram 3] FIG. 3 is a side view of a portion of the sealing arrangement of FIG. 2 with parts removed for clarity. [Figure 4] FIG. 4 is an enlarged perspective view of a portion of FIG. 3 with parts removed for clarity. [Diagram 5] 3 is a side view of a portion of the seal apparatus of FIG. 2 with parts removed for clarity in accordance with one or more embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Number 1 indicates as a whole a packaging machine for producing 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 a composite package 2 from a composite multi-layer packaging material.

[0027] More specifically, the packaging material may comprise at least one layer of fibrous material, such as paper or paperboard, and at least two layers of heat-sealable plastic material, such as polyethylene, sandwiched between the layers of fibrous material, one of the two layers of heat-sealable plastic material defining the inner surface of the body 2 in contact with the pourable product.

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

[0029] More particularly, the packaging material may be provided in the form of a web 3 .

[0030] Additionally, 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, sealing the tube 4 transversely, and cutting.

[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 sealing bands arranged on opposite sides of the package 2. In particular, the first transverse sealing band may define a transverse top sealing band and the second transverse sealing band may define a transverse bottom sealing band.

[0032] Referring to FIG. 1, a packaging machine 1 includes: 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 apparatus 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 former 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 also comprise a sterilization unit configured to sterilize the advancing web 3, in use, at a sterilization station, which may in particular be arranged along the web advancement path P upstream of the forming station 8.

[0034] More specifically, the conveying device 7 may in particular be configured to advance the tube 4 and any intermediate part of the tube 4 along the tube advancement path Q from the forming station 9 to the package forming device 16. In particular, by intermediate part of the tube 4 is meant any configuration of the web 3 before obtaining the tube structure and after the 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 particularly, the tube forming and sealing apparatus 10 may include at least two forming ring assemblies 16 disposed within the isolation chamber 9 and configured to cooperate with one another to gradually fold the web 3 into the tube 4, in particular by overlapping edges of the web 3 with one another, thereby forming a seam 5 in the tube 3, in use.

[0037] Additionally, the tube forming and sealing apparatus 10 may include a sealing head 17 , particularly disposed within the isolation chamber 9 , configured to longitudinally seal the tube 4 along the seam 5 .

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

[0039] Furthermore, the filling device 11 may include a filling pipe 18 configured to, in use, direct the pourable product into the tube 4. In particular, the filling pipe 18 may be at least partially disposed 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 molding machine 12 includes: a plurality of forming and sealing assemblies 19 (only partially shown in FIG. 2 to the extent necessary for an understanding of the invention), each forming and sealing assembly being configured 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, but known per se) for advancing the forming and sealing assembly 19; The present invention may also include:

[0041] In particular, the package former 12 is configured to control the form and seal assembly 19 and transfer units to transversely seal and cut the tube 4 along equally spaced transverse cross sections.

[0042] More specifically, each molded and sealed assembly 19 includes: a molded shell (not shown, but known per se) configured to at least partially define the shape of the package 2; a sealing device 20 configured for at least laterally compressing, in particular squeezing flat, and laterally sealing 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 transversely cutting the tube 4 .

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

[0045] More particularly, each molded shell may comprise at least a first half shell (not shown, as known) and a second half shell (not shown, as known) 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 are configured to contact opposite sides of the tube 4.

[0046] More specifically, each sealing device 20 is of the ultrasonic type, i.e. it is 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 the respective parts of the layer of heat-sealing plastic material; an anvil 22 for compressing, in particular for locally flattening and squeezing, in cooperation with the sonotrode 21 and the tube 4; The present invention may also include:

[0048] More specifically, each cutting device comprises at least one movable blade for cutting the tube 4 transversely.

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

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

[0051] Further, the transport unit may be configured to advance each first manipulator along a first path and to advance each second manipulator 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 progress along the respective operating portions of the first path and the second path, respectively.

[0053] Referring to Figures 3 and 4, each sonotrode 21 comprises at least: a sonotrode head 23 having a sealing surface 24 extending in particular along a 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 operable connection with a portion of the layer of heat seal plastic.

[0055] Further, each sealing surface 24 may include a first portion 26 and a second portion 27 disposed parallel to and spaced apart from one another.

[0056] Furthermore, each sonotrode head 23 may in particular include a groove 28 interposed between the respective first portion 26 and the respective second portion 27. In particular, each groove 28 is designed to receive a portion of a respective blade when cutting the tube 4 transversely.

[0057] 2 to 4, each vibration control unit 25 may comprise one or more piezoelectric transducer devices 35 (shown in Figs. 3 and 4) configured to generate ultrasonic vibrations that are coupled to the respective sonotrode head 23. In the illustrated example, the vibration control unit 25 comprises three piezoelectric transducer devices 35, but the number may vary depending on the type of package 2. That is, depending on the type of package 2, the extension of the sealing surface 24 may be greater or less. In particular, if the sealing surface 24 is shorter, fewer piezoelectric transducer devices 35 are required than if it is larger.

[0058] Further, each vibration control unit 25 may include one or more temperature sensors 36 configured to measure (directly or indirectly) the temperature of the piezoelectric transducer 35 in order to determine and / or control the operating state of each of the piezoelectric conversion devices 35.

[0059] In particular, Applicant has observed that the temperature of each piezoelectric transducer device 35 is indicative of the operational characteristics of the piezoelectric transducer device 35 and / or of the aging of the piezoelectric transducer device 35 and / or of the remaining life of the piezoelectric transducer device 35. For example, Applicant has found that each piezoelectric transducer device 35, as a result of its operation, degrades over time resulting in increased heat dissipation during use.

[0060] Preferably, the temperature sensor 36 is configured to measure the temperature of the piezoelectric conversion device 35 continuously and / or in real time, and in particular to determine and / or monitor the operating condition of the piezoelectric conversion device 35 continuously and / or in real time.

[0061] According to the illustrated embodiment, at least one temperature sensor 36 is associated with each piezoelectric transduction device 35 to measure the respective temperature and to determine and / or monitor the operational status of each piezoelectric transduction device 35 .

[0062] According to some possible embodiments, each temperature sensor 36 is connected to a respective piezoelectric transducing device 35 so as to (directly) measure the respective temperature.

[0063] Alternatively, each temperature sensor 36 can determine its respective temperature in a non-contact mode.

[0064] According to some possible alternative embodiments, it is also possible to determine the temperature of the piezoelectric transducer 35 by the average temperature of each piezoelectric transducer 35 of each sealing device 20 .

[0065] More specifically, each temperature sensor 36 may be a thermistor, i.e., the temperature determined by the temperature sensor 36 results from a change in resistance of the temperature sensor 36.

[0066] More specifically, each temperature sensor 36 may be a negative temperature coefficient (NTC) thermistor (i.e., the resistance decreases with increasing temperature) or a positive temperature coefficient (PTC) thermistor (i.e., the resistance increases with increasing temperature).

[0067] It should be noted that the accuracy of such type of temperature sensor 36 is about + / - 0.5°C. Such accuracy is therefore limited compared to other types of temperature sensors. However, the applicant has discovered that the accuracy provided by thermistors, in particular NTC and PTC thermistors, is sufficient to determine and / or monitor the operating state of the piezoelectric conversion device 35. Thus, by using thermistors, in particular NTC and PTC thermistors, it is possible to obtain a more economical solution to other types of temperature sensors that are more expensive but still reliably determine the operating state of the piezoelectric conversion device 35.

[0068] 4, each piezoelectric transducer device 35 may include a plurality of piezoelectric (ceramic) elements 37 stacked on top of each other. More specifically, each piezoelectric transducer device 35 may include a plurality of conductive metal sheets, in particular forming a stack of alternating piezoelectric elements 37 and conductive metal sheets together with the piezoelectric elements 37. Preferably, each temperature sensor 36 may be configured to measure the temperature of each piezoelectric element 37.

[0069] Further, each sealing device 20, and in particular each vibration control unit 25, may comprise one or more generators (not shown, but known) operably connected to the piezoelectric conversion device 35, and in particular the piezoelectric element 37, so as to operate and control the ultrasonic vibrations of the piezoelectric conversion device 35.

[0070] Furthermore, each piezoelectric transducer device 35 may comprise at least one metal connector 38 designed to establish an electrical connection with at least one generator, in particular connected to one respective conductive metal sheet. In particular, each vibration control unit 25 comprises one or more electrical cables 39 connected to at least one generator and to at least one metal connector 38, in order to establish an electrical connection between the generator and the metal connector 38.

[0071] Advantageously, each temperature sensor 36 contacts a respective metal connector 38 of a respective piezoelectric transducer device 35 (so as to establish contact with the respective piezoelectric transducer device 35 ).

[0072] Preferably, each metal connector 38 may in particular comprise copper, which has very good thermal properties, thereby ensuring that the temperature determined by the respective temperature sensor 36 corresponds to the temperature of the respective piezoelectric transducer device 35, in particular the respective piezoelectric element 37.

[0073] According to some possible non-limiting embodiments, the packaging machine 1, in particular the package forming apparatus 12, may be equipped with at least one analysis unit 40 operably coupled to a temperature sensor 36 and configured to monitor and / or determine the operating state of the piezoelectric conversion device 35 depending on the temperature determined by the temperature sensor 36.

[0074] According to some possible non-limiting embodiments, each sealing device 20 comprises a respective portion of an analysis unit 40 operably connected to a respective temperature sensor 36 so as to determine the temperature of the respective piezoelectric conversion device 35, and in particular, each portion of the analysis unit 40 is configured to monitor and / or determine the operating state of the piezoelectric conversion device 35 depending on the temperature determined by the temperature sensor 36.

[0075] Furthermore, the analysis unit 40 and / or parts of the analysis unit 40 may be configured to plan maintenance activities based on the operating state of the piezoelectric transducer device 35. In particular, the analysis unit 40 and / or parts of the analysis unit 40 may be configured to plan maintenance activities as a function of the remaining life and / or aging of the piezoelectric transducer device 35. In this way, the use of the piezoelectric transducer device 35 can be optimized.

[0076] For example, each analysis unit 40 and / or portions of the analysis unit 40 may signal the remaining life of the piezoelectric transducer device 35 and indicate that maintenance should be performed within a particular time frame.

[0077] Furthermore, the analysis unit 40 and / or parts of the analysis unit 40 may be configured to assess the likelihood of the occurrence of an abnormal operating condition based on the temperature measured by the temperature sensor 36. Furthermore, the analysis unit 40 and / or parts of the analysis unit 40 may be configured to warn about the risk of an abnormal operating condition, for example by means of a prompt on a human-machine interface (of the packaging machine 1) and / or an acoustic message and / or a similar electronic message.

[0078] Furthermore, each vibration control unit 25 may comprise at least a housing shell 41 (shown in FIG. 3, the transparent representation is for illustrative purposes) having an interior space 42. In particular, the housing shell 41 contacts the respective sonotrode head 23 so as to seal the interior space 42 from the exterior space.

[0079] Preferably, each piezoelectric transducer device 35 and each temperature sensor 36 is arranged within the respective interior space 42. In particular, each generator may also be arranged within the respective interior space 42.

[0080] Furthermore, each vibration control unit 25 may comprise a coupling portion 43 that contacts the respective sonotrode head 23 along a respective contact surface. Furthermore, each piezoelectric transducer device 35 may be disposed within a respective sheet 44 (see in particular FIG. 3 ) of the respective coupling portion 43 and in contact with the coupling portion 43 so as to be able to transmit the generated ultrasonic vibrations to the respective sonotrode head 23.

[0081] In use, the packaging machine 1 produces packages 2 filled with a pourable product.

[0082] 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.

[0083] 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 .

[0084] Thereby, shaping takes place by the respective shaping shells, in particular by the respective first and second half shells cooperating with one another.

[0085] Further, lateral sealing is provided by respective sealing devices 20 .

[0086] Furthermore, the transverse cuts are carried out by respective cutting devices.

[0087] More specifically, the operation of each sealing device 20 is as follows: - compressing, in particular squeezing flat, the tube 4 by the cooperation of the respective anvil 22 and the respective sonotrode 21; - generating ultrasonic vibrations by means of a sonotrode 21 to heat a portion of the layer of heat-sealing plastic; At least the following is provided.

[0088] More specifically, the operation of each sealing device 20 is as follows: a) exciting ultrasonic vibrations of each sonotrode head 23 by operation of the vibration control unit 25 and the respective piezoelectric transducer device 35; b) measuring the temperature of each piezoelectric transducer device 35; c) determining, in particular by the analysis unit 40 and / or each part of the analysis unit 40, the operating state of each piezoelectric transducer device 35 based on the temperature obtained in step b); It further comprises:

[0089] More specifically, during each step b), the temperature of each piezoelectric conversion device 35 may be measured by a respective temperature sensor 36, and during step c), the operating state of each piezoelectric conversion device 35 may be determined according to the respective temperature determined during each step b).

[0090] Preferably, steps b) and c) may be carried out consecutively.

[0091] Furthermore, the operation of each sealing device 20 may further include a transfer step, in which the measurement result of the temperature sensor 36 is transferred to the analysis unit 40 and / or a respective part of the analysis unit 40 .

[0092] More specifically, in step c), the remaining life and / or ageing of the piezoelectric transducing device 35 may be estimated.

[0093] Furthermore, the operation of each sealing device 20 may further include the step of: d) scheduling maintenance based on the operational state of one or more piezoelectric transducer devices 35. In particular, in this way, maintenance can be scheduled based on the effective remaining life and / or aging of the piezoelectric transducer devices 35.

[0094] Furthermore, operation of each sealing device 20 may include a warning step during which the risk of an abnormal working condition may be signalled, for example by a prompt on a human-machine interface, and / or an acoustic message, and / or a similar electronic message.

[0095] 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.

[0096] In particular, by providing a temperature sensor 36, it is possible to measure the temperature of the piezoelectric conversion device 35 and monitor and / or determine the operating state of the piezoelectric conversion device 35 depending on the measured temperature. In this way, it is possible to monitor whether the piezoelectric conversion device 35 operates in a correct manner and / or to determine the remaining life and / or aging of the piezoelectric conversion device. This allows a decision to perform or not to perform a maintenance action based on the actual aging of the piezoelectric conversion device 35 without following a predefined schedule. This ensures that undesired breakdowns and unnecessary maintenance actions are avoided.

[0097] A further advantage lies in the possibility of obtaining real-time data regarding the operating status of the piezoelectric conversion device 35, which allows for rapid response and further reduces the risk of operational anomalies that may prevent the correct operation of the sealing device 20.

[0098] Another advantage is the connection of the temperature sensors 36 to respective metal connectors 38 which are already used to connect the piezoelectric transducer devices 35, in particular the piezoelectric elements 37, to the respective generators by respective electrical cables 39. In this way, space requirements are optimized.

[0099] A further advantage is the use of a thermistor as the temperature sensor 36. Thermistors are relatively inexpensive, easy to install, and may be accurate enough for certain applications.

[0100] However, changes can obviously 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.

[0101] One or more embodiments therefore relate to a sealing device 20 for sealing packages 2 filled with a pourable product in a packaging machine 1, a part of which is shown in Figure 5. The reference numbers used with reference to Figure 5, where they correspond to reference numbers previously used with reference to the remaining figures, have the same meaning and refer to the same features.

[0102] The sealing device 20 comprises at least one sonotrode 21 consisting of at least 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 .

[0103] As illustrated in FIG. 5, the vibration control unit 25 includes: one or more piezoelectric transducer devices 35 configured to generate ultrasonic vibrations coupled to the sonotrode head 23; - one or more electrical cables 39 configured to provide power (e.g. provide electrical connection and power) to each of the one or more piezoelectric transducer devices 35, the one or more electrical cables 39 being connected to the respective one or more piezoelectric transducer devices 35 via a first end 39b; one or more temperature sensors 36 configured to measure (e.g. directly or indirectly) the temperature of the one or more piezoelectric transducer devices 35 in order to determine and / or monitor the operating state of each of the one or more piezoelectric transducer devices 35 by measuring the temperature of the first end 39b of the one or more electric cables 39; The present invention may also include:

[0104] In other words, the temperature sensor 36 may be configured to measure the temperature of the first end 39b of the electric cable 39, which is indicative of the temperature of the respective piezoelectric transducer device 35. In this way, a reliable, accurate and reliable measurement of the temperature of the piezoelectric transducer device 35 can be obtained without direct contact with the piezoelectric transducer device 35. In particular, the temperature at the first end of the electric cable 39 closest to the piezoelectric transducer device 35 is very similar to the temperature of the piezoelectric transducer device 35, so that an accurate measurement of the temperature of the piezoelectric transducer device 35 can be obtained. The embodiment shown in FIG. 5 may be advantageous in that it is particularly robust in view of vibrations of the piezoelectric transducer device 35.

[0105] The one or more temperature sensors 36 may be disposed at a first end 39 b of each of the one or more electrical cables 39 .

[0106] Each electrical cable 39 may include an electrical wire and a protective sheath 39a surrounding the electrical wire. As shown in Figure 5, one or more temperature sensors 36 may be disposed between the protective sheath 39a and the electrical wire of each one or more electrical cables 39, for example at a first end 39b.

[0107] For example, the temperature sensor(s) 36 may be fully or partially covered by the protective sheath 39a of the respective electrical cable(s) 39. For example, the temperature sensor 36 may be pressed against and / or held in contact with the electrical wiring by the sheath 39a. For example, the electrical cable 360 ​​supplying power to the temperature sensor 36 may likewise be disposed between the protective sheath 39a and the electrical wires of the respective electrical cable(s) 39 and may, for example, be fully or partially covered by the protective sheath 39a.

[0108] More specifically, each electric cable 39 may be connected to at least one generator and at a first end 39b to at least one metal connector 38 of the piezoelectric transducer device 35 so as to establish an electrical connection between the generator and the metal connector 38. The temperature sensor 36 may be configured to measure the temperature of the first end 39b, such temperature being indicative of the temperature of the piezoelectric transducer device 35 and the metal connector 38. In this way, instead of measuring the temperature of the metal connector 38, it is possible to measure the temperature of the first end of the electric cable 39 and still obtain a reliable, robust and accurate measurement of the temperature of the piezoelectric transducer device 35.

[0109] The temperature measurements obtained by the temperature sensor 36 at the first end 39b of the electrical cable 39 may indicate the temperature of the respective one or more piezoelectric transducer devices 35. The analysis unit 40 may receiving one or more temperatures measured at a first end 39b of one or more electrical cables 39; It may be configured to calculate the temperature of the one or more piezoelectric transducer devices 35 as a function of the measured temperature or temperatures and preferably a correction factor, for example a linear correction factor.

[0110] For the avoidance of doubt, each piezoelectric transducer device 35 has a respective electrical cable 39 that provides power thereto. Also, each temperature sensor 26 may be located at an end 39b of a respective electrical cable 39. That is, each temperature sensor 36 is associated with (e.g., in contact with or in close proximity to) a single electrical cable 39 and a single piezoelectric transducer device 35.

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), The sonotrode is Sonotrode head (23); 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 (35) configured to generate ultrasonic vibrations coupled to the sonotrode head (23); one or more temperature sensors (36) configured to measure a temperature of the one or more piezoelectric transducer devices (35) to determine and / or monitor an operational state of each of the one or more piezoelectric transducer devices (35); Equipped with A sealing device (20).

2. the one or more temperature sensors (36) are operably connected and / or coupleable to an analysis unit (40) configured to monitor and / or determine an operating state of the one or more piezoelectric transducer devices (35) depending on the temperature measured by the one or more temperature sensors (36); The sealing device of claim 1 .

3. the one or more temperature sensors (36) are associated with each piezoelectric transducer (35) to measure a temperature of the respective piezoelectric transducer (35) to determine and / or monitor an operating condition of the respective piezoelectric transducer (35); The sealing device of claim 1 .

4. Each temperature sensor (36) is in contact with a respective piezoelectric transducer device (35); The sealing device according to claim 3.

5. each said piezoelectric transducer device (35) comprises a metal connector (38) designed to establish an electrical connection with a generator of said sealing device (20); Each of the temperature sensors (36) contacts the metal connector (38) of the respective piezoelectric transducer device (35). The sealing device according to claim 3.

6. the metal connector (38) comprises copper; The sealing device according to claim 5.

7. the vibration control unit (25) comprises one or more electrical cables (39) configured to supply power to each of the one or more piezoelectric transducer devices (35); the one or more electrical cables (39) are connected to the respective piezoelectric transducer devices (35) via first ends (39b) of the electrical cables (39); the one or more temperature sensors (36) are configured to measure a temperature of the one or more piezoelectric transducer devices (35) by measuring a temperature of the first ends (39b) of the one or more electric cables (39); The sealing device of claim 1 .

8. the one or more temperature sensors (36) are disposed at the first ends (39b) of the respective one or more electrical cables (39); The sealing device according to claim 7.

9. each electric cable (39) comprises an electric wire and a protective sheath (39a) surrounding said electric wire, said one or more temperature sensors (36) being disposed between said protective sheath (39a) and said electric wire of said respective one or more electric cables (39); The sealing device according to claim 7.

10. Each temperature sensor (36) is a thermistor; The sealing device of claim 1 .

11. each said temperature sensor (36) being a negative temperature coefficient thermistor or a positive temperature coefficient thermistor; The sealing device of claim 10.

12. The vibration control unit (25) further comprises at least a housing shell (41) having an interior space (42); Each piezoelectric transducer (35) and each temperature sensor (36) are disposed within the internal space (42). The sealing device of claim 1 .

13. the operating condition of the one or more piezoelectric transducer devices (35) is the respective lifetime and / or respective aging and / or operating characteristics of the one or more piezoelectric transducer devices (35); The sealing device of claim 1 .

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

15. 2. A method of operating the sealing device (20) of claim 1, comprising the steps of: a) exciting ultrasonic vibrations in the sonotrode head (23) by operation of one or more piezoelectric transducer devices (35); b) measuring the temperature of the one or more piezoelectric transducer devices (35); c) determining an operating state of the one or more piezoelectric transducer elements (35) based on the temperature obtained in step b); The method includes at least the following steps.

16. During said step b), the temperature of each piezoelectric transducer device (35) is measured by a respective temperature sensor (36); During said step c), the operating state of each of said piezoelectric transducer devices (35) is determined in response to the respective temperatures determined during said step b). The method of claim 15.

17. During said step c), the remaining life and / or aging of said one or more piezoelectric transducer devices (35) is estimated. The method of claim 15.

18. d) scheduling maintenance based on the operational status of the one or more piezoelectric transducer devices (35); The method of claim 15.

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