EP3587285A1 - Method for volume flow and fill level determination on a packaging machine - Google Patents

Abstract

Method for operating a sealing station (3) of a packaging machine (1) for producing packaging (V) with a packaging optics which is at least substantially similar to one another with possibly varying degrees of filling (22), comprising carrying out a comparison (C) of a recorded pressure curve (27) with a reference pressure curve (28), and the calculation (D) of a degree of filling (22) of the packaging (V) positioned within the sealing station (3) based on the comparison of the detected pressure curve (27) with the reference pressure curve (28), and / or the calculation of a volume flow (V) with respect to the pressure curve (27) or the reference pressure curve (28), and the setting (E) of at least one process parameter (PP) on the packaging machine (1) taking into account the calculated degree of filling (22) and / or Volume flow (V).

Description

The invention relates to a method for producing packaging with a packaging optics that is at least substantially similar to one another according to claim 1. Furthermore, the invention relates to a packaging machine for producing packaging with a packaging optics that are at least substantially similar to one another according to independent claim 13.

The invention is in particular the following in connection with Fig. 1 described problem underlying.

Fig. 1 shows a schematic representation of a sealing station S '. The sealing station S 'comprises an upper sealing tool part SO' and a lower sealing tool part SU ', which can be brought together by means of a lifting movement H' to form an airtight sealed sealing chamber SK '. For a gassing and / or evacuation process, an upper film O 'and a lower film U' are brought together within the sealing chamber SK 'in such a way that they enclose a packing volume P' between them, which essentially consists of the sum of a partial volume V1 'that of each into the lower film U 'formed packaging trays VM' minus the product contents I 'present, and a partial volume V2' which is above the respective packaging trays VM 'and is enclosed by the upper film O'.

The package volume P 'is generally larger than the total of the individual volumes enclosed by the packaging produced, so that a gas distribution can take place between the packages, particularly during gassing. This results in the in Fig. 1 shown, in the sealing tool upper part SO ', a positioning of a sealing tool SW' stored therein above the packaging troughs VM 'positioned within the sealing station S', a gap SP 'between the lower and upper film U', O ', through which the supplied gas can be found in all can distribute packaging positioned within the sealing station S '.

When the packing volume P 'is compressed again, i.e. when the top film O' is pressed down for the sealing process, packaging with a varying packing appearance can be produced despite an optimized gassing process, for example using an adjustable step throttle, because it happens again and again that doing that Packaging are produced that have different top film curvatures, for example, inflated or rather indented.

These optical deviations are caused in the sealing process by the lifting (lowering) of the sealing tool SW '. Since the sealing tool SW 'is initially positioned in the upper part of the sealing tool SO' during the gassing process in order to create the gap SP 'necessary for the distribution of the gas, the sealing tool SW' is then moved downwards in the direction of the packaging trough VM positioned below for the sealing process 'shifted, whereby it displaces the partial volume V2 initially created'. By moving the sealing tool SW 'down, the fumigated partial volume V2' is pressed into the partial volume V1 ', so to speak as an additional volume. As a result, the pressure in the packaging increases. Depending on the contents of the packaging I ', this creates packaging with a different packaging appearance.

The following applies here, the smaller the freely available partial volume V1 ', the greater the influence of the partial volume V2' displaced by the sealing stroke on the pressure change within the finished packaging.

So far, attempts have been made to counteract the problem described above with a preset gassing offset printing, i.e. At the beginning, the gas was only gassed to a pressure reduced by the gassing offset pressure, in the hope that the desired set pressure within the packaging would then be achieved through the sealing stroke.

However, the use of a gassing offset printing requires knowledge of the degree of filling of the respective packaging to be closed, whereby it has previously been assumed for the sake of simplicity in conventional applications that the product line has a constant degree of filling across the respective packaging. As a result, it always becomes problematic if the respective packaging, contrary to the aforementioned assumption, does not have a uniform degree of filling, which can be particularly true for nominal weight products with a varying product density, for example sliced meat or cheese. Despite the use of a predetermined gassing offset printing, finished packaging with a different visual appearance results due to varying fill levels.

In addition, the gassing offset printing previously had to be calculated manually during an adjustment process and entered as arithmetic parameters on the packaging machine, so that its use is reserved for specially trained operating personnel.

Working with constant, preset process parameters therefore does not deliver the desired manufacturing quality and can be optimized in particular with a view to manufacturing tailored to each individual product.

Operating a packaging machine assuming a constant degree of filling over the respective packaging and / or a constant volume flow predetermined for the gassing in this regard, without taking into account the actual actual degree of filling of individual packaging, can lead to a not inconsiderable amount of rejects.

This can be influenced by the fact that empty packaging repeatedly runs through the gassing and / or evacuation process temporarily, for example due to interruptions in the product supply. The empty packaging then carried falsifies the fumigation and / or evacuation process extremely, provided that rigidly preset process parameters are used. As a result, the desired appearance is not produced, at least on the filled packs processed together with the empty packs in one work cycle.

The EP 2 668 102 B1 discloses a packaging machine and a method for producing individually evacuated and / or fumigated packaging. It is generally further disclosed that an agent can be used with which the fill level of the packaging goods in the respective packaging tray and / or the filling quantity of the packaging goods within the respective packaging tray can be determined. Depending on this measurement signal, a shut-off device can then be regulated, for example, in order to individually regulate the gas volume that is removed or supplied from the respective packaging tray.

The object of the invention is to produce a method and a device for the production of packaging with a packaging optic which is at least substantially similar to one another. This should be possible even if the respective packaging has varying degrees of filling, i. H. are voluminously filled unevenly.

This object is achieved by means of a method according to claim 1 and by means of a packaging machine according to independent claim 13.

Improved developments of the invention are the subject of the respective subclaims.

• Befüllen eines zwischen einem unteren und einem oberen Verpackungsmaterial eingeschlossenen, freien Packungsvolumens mindestens einer innerhalb der Siegelstation positionierten Verpackung mit einem zur Schaffung einer gewünschten Atmosphäre bestimmten Gas von einem im Packungsvolumen herrschenden Ausgangsdruck auf einen vorbestimmten Begasungsdruck,
• Erfassen eines Druckverlaufs zumindest temporär während des Befüllens des Packungsvolumens mittels mindestens einer damit verbundenen, druckerfassenden Sensorik, wobei der Druckverlauf vorzugsweise anhand einer zeitabhängigen Druckkurve zwischen dem Ausgangsdruck bis hin zu dem vorbestimmten Begasungsdruck erfasst wird,
• Vergleichen des erfassten Druckverlaufs mit einem Referenzdruckverlauf, der vorzugsweise anhand einer seinerseits zeitabhängigen Druckkurve für ein Befüllen eines bekannten freien Referenzpackungsvolumens mindestens einer innerhalb der Siegelstation positionierten, insbesondere leeren Referenzverpackung mit dem Gas zwischen dem Ausgangsdruck bis hin zu dem vorbestimmten Begasungsdruck erfasst wird,
• Berechnen eines Füllgrads der innerhalb der Siegelstation positionierten Verpackung basierend auf dem Vergleich des erfassten Druckverlaufs mit dem Referenzdruckverlauf und/oder eines Volumenstroms bezüglich des Druckverlaufs oder des Referenzdruckverlaufs, und
• Einstellen mindestens eines Prozessparameters an der Verpackungsmaschine unter Berücksichtigung des berechneten Füllgrads und/oder des Volumenstroms.

The invention relates to a method for operating a sealing station of a packaging machine, in particular a thermoforming packaging machine. The procedure is for this configured to produce packaging with an at least substantially similar packaging optics with possibly varying degrees of filling. The method according to the invention comprises the following steps:

• Filling a free package volume enclosed between a lower and an upper packaging material at least one package positioned within the sealing station with a gas intended to create a desired atmosphere from an initial pressure prevailing in the package volume to a predetermined gassing pressure,
• Detection of a pressure curve at least temporarily during the filling of the package volume by means of at least one pressure-sensing sensor connected to it, the pressure curve preferably being recorded on the basis of a time-dependent pressure curve between the initial pressure and the predetermined gassing pressure.
• Comparing the recorded pressure curve with a reference pressure curve, which is preferably recorded using a time-dependent pressure curve for filling a known free reference pack volume of at least one, in particular empty, reference pack positioned within the sealing station with the gas between the initial pressure up to the predetermined gassing pressure,
• Calculating a degree of filling of the packaging positioned within the sealing station based on the comparison of the detected pressure curve with the reference pressure curve and / or a volume flow with respect to the pressure curve or the reference pressure curve, and
• Setting at least one process parameter on the packaging machine taking into account the calculated degree of filling and / or the volume flow.

In the present invention, by considering the current pressure profile during the gassing process, a degree of filling of a "deduction" provided within the sealing station, ie the respective packaging processed per machine cycle in one operation at the sealing station, and possibly based thereon, is adapted to the respective deduction determines the volume flow of the fumigation medium.

The essence of the invention is, at least temporarily, but preferably right at the beginning of the gassing process, to record the pressure curve on a respective trigger and to compare it with a reference pressure curve, which is generated and recorded, for example, on a trigger from empty packaging, with a Analysis, i.e. a comparison of the respective gradients of the pressure increases is possible, the degree of filling of the currently available print, i.e. the packaging positioned within the sealing station, as well as, if necessary, also an optimal volume flow of the gassing medium used to calculate the processing of the existing deduction and / or at least one subsequent deduction process-controlled.

The invention therefore makes it possible that current filling degree and / or volume flow values per machine cycle can be recorded and used as process parameters, in particular as the basis for calculating at least one process parameter for the manufacturing process, be it at the sealing station itself and / or at other work stations of the packaging machine.

In particular, it is possible on the basis of the invention that the comparison of the pressure curve with the reference pressure curve is timely, i.e. during a predeterminable time window at the beginning of the filling, it is carried out that a filling level and / or a volume flow is predictable (calculable) for the same deduction, so to speak in real time, that during a remaining running time of the filling, i.e. before a variable gassing end pressure within the Packing volume, the process parameter is adjustable. In other words, the time window for the aforementioned comparison can be timed such that the present deduction can itself be influenced in a process-controlled manner based on the comparison carried out in this regard. Such advantageous cascading can lead to higher process accuracy.

The invention is based on process steps which can be carried out in a simple manner in order to better adapt the manufacturing process to possibly varying fill levels, which has the consequence that improved product quality, that is to say packagings with a packaging optics which are at least substantially similar to one another, can be produced.

The invention is particularly suitable for the qualitative packaging of respectively weighted products with a varying product volume, in particular for packaging fresh meat or cheese with a varying product density. Even in the event that empty packaging is included in the product line during the manufacturing process for procedural reasons, its "empty contents" can be determined using the inventive method Optimally compensate for process steps so that even with a deduction with empty packaging enclosed therein, packaging with the desired packaging appearance can be produced.

To derive the degree of filling, in particular for carrying out the comparison of the detected pressure curve with the reference pressure curve, it can be expedient to assume an isothermal change in state under the same volume flow conditions, preferably with the same pressure conditions and possibly with the same throttle valve position. The derivation is preferably based on the Boyle-Mariotte law as a theoretical basis. It is particularly advantageous if, based on at least one process parameter preset at the sealing station (e.g. gassing temperature, volume flow, pressure ratio, throttle position for gassing, etc.), a corresponding reference pressure curve can be called up to carry out the inventive method, so that the inventive method is used in the production of various Packaging types can be used.

An advantageous variant of the invention provides that a quotient of a ratio of a time recorded for the pressure curve and a time recorded for the reference pressure curve is subtracted from a whole in order to calculate the degree of filling.

A recording and / or calculation unit, which may be an integral part of a control unit of the packaging machine, is preferably used to record and / or calculate the elapsed time for the pressure curve increasing between different pressure levels, which results during the filling within the packaging positioned in the sealing station is.

It can be advantageous that a variable time window can be selected for recording the pressure curve on the packaging machine. For example, for longer gassing processes, a larger time window could be selected to record the pressure curve because this enables a more precise prediction of the degree of filling and / or volume flow present.

The time-based comparison with the reference pressure curve can still take place during the gassing on the basis of a previously recorded and / or calculated time for the reference pressure curve. For this purpose, a memory of the packaging machine preferably has at least one time-dependent reference pressure curve predetermined for the packaging format, with respect to which the degree of filling of the current print can be determined. For the process-controlled comparison, in particular reference pressure profiles of different packaging formats can be kept ready are, so that the invention can be used for an optically homogeneous production of different packaging formats. The comparison can be particularly meaningful if comparable process parameters, for example the same volume flows, are used to produce the reference pressure curve and the recorded pressure curve.

In this context, it can in particular be the case that the degree of filling and / or the volume flow is calculated in real time per machine cycle and an automated adjustment of the process parameter is carried out on this basis. In real time, this means that the automated adaptation of the process parameter takes place during the same work cycle, and in particular can also concern an adjustment of the gassing process currently being carried out, during which the degree of filling is determined.

It is advantageous if the process parameter is an offset printing, which is still used in the current filling process and / or in at least one subsequent filling process, in order to fill the package volume with gas only until a pressure is reached that results from a gassing target pressure for finished packaging minus the calculated offset print results.

For an improved production quality, the offset printing could be adjusted automatically at least at intervals, but preferably per machine cycle, so that varying fill levels can be better taken into account during production. It would then be possible, in particular, to continuously adapt the filling pressure to the detected filling levels, so that the subsequent sealing stroke in the interior of the packaging precisely produces the gassing target pressure. As a result, optically equivalent packaging, i.e. packaging with the same gassing target pressure, can leave the sealing station.

The Boyle-Mariotte law is expediently used to calculate the offset printing, taking into account a partial volume of the packaging volume displaced by a sealing stroke and a free packaging volume that can be determined in view of the calculated degree of filling, including the gassing target pressure of finished packaging to be produced therein. When applying the Boyle-Mariotte law, an isothermal pressure equalization between the packaging positioned within the sealing station can be assumed.

The process parameter is preferably a gas velocity which is achieved at the respective gas pins designed to fill the packing volume. Given the nature of the products, particularly the nature of food products, this can in the packaging can be useful. For example, it matters whether dimensionally stable, one-piece products with a solid surface finish, such as B. a piece of cheese, or products with unstable, especially applied surface texture, e.g. B. breaded meat, be gassed. Packaging with a high filling level, in which breaded meat is inserted, could be gassed with reduced gas velocity to avoid damage to the breading layer. On the other hand, for an increased production rate, gassing with a higher gas velocity could in principle be set in the case of one-piece package contents formed with a stable surface, in particular if a low degree of filling is detected.

According to one embodiment, the process parameter is a valve setting value, in particular a throttle valve position, which influences an evacuation and / or the gassing process. This could influence the pressure course within the pack volume in a targeted manner. The valve setting value is preferably continuously adapted automatically during the manufacturing process, so that optimum process settings can always be used. This particularly favors exact fumigation and offers excellent control for the production of optically equivalent products.

One embodiment variant provides that the process parameter triggers a malfunction indicator on the packaging machine. In this way, for example, leaks during the production process, in particular during the gassing and / or evacuation process within the sealing station, can be detected and can be displayed to the operating personnel immediately, so that the production can be interrupted if necessary, for example to adapt process parameters to the packaging machine.

The (free) pack volume is preferably connected to a collecting volume of known size and the (free) pack volume is calculated based on a detected pressure compensation. An external storage, an external gas tank or a volume created by the upper part of the sealing station can be used as the collecting volume of known size. This procedure can be used in particular for the precise calculation of a reference packaging volume of empty packaging of a print, which can then be used in the calculation of the reference pressure curve.

A separately provided gas tank could be designed so that it can be shut off by means of an additional valve, so that the pressure equalization between it and the free pack volume can be precisely regulated. After the packaging has been gassed to a desired pressure, a change in pressure in the gas tank can then be recorded, which is used to calculate the volume transition is used as a basis from which the remaining volume, i.e. the (free) pack volume, can be calculated. The Boyle-Mariotte law could in turn be used as the basis for the calculation.

An improved variant provides that the process parameter is set continuously in view of the averaged values of the degree of filling and / or the volume flow. This can reduce the tax expense on the packaging machine. This can be particularly advantageous in an operating situation in which there is a high probability that small changes in the degree of filling occur, for example when packaging sliced sausages.

According to a variant, the package volume filled with gas is formed in such a way that a pressure equalization takes place between several packages positioned within the sealing station during the gassing process, in particular during the sealing stroke. The respective packaging enclosed within a sealing chamber can be connected via a gap formed between the upper and the lower packaging material. Here, the process parameter can be an adjustable speed of a lifting movement of the sealing tool, which is adjustably mounted within the sealing station, so that it moves in such a way that the pressure equalization between the several packs provided can take place reliably.

A supply volume connected with the packing volume, which results, for example, from a gassing line, an evacuation line and / or a tool volume, is preferably eliminated when the degree of filling is calculated. Additionally or alternatively, the sealing plate stroke, i. H. the partial volume of the pack displaced as a result, given the known geometries of the upper part of the sealing tool, should be eliminated when calculating the degree of filling. Assuming that these values, which may falsify the degree of filling calculation, remain constant, standard values that are stored in the machine control can be used for this.

The principle according to the invention, which precedes the gassing process, could already take place during an evacuation process. It would thus be possible to functionally transfer the statements previously described in connection with the invention to the evacuation process, so that a process-controlled parameter setting based thereon can already take place during the evacuation process.

With the aid of the invention, process parameters can preferably also be set outside the sealing station, ie at other workstations of the packaging machine, such that the respective workstations of the packaging machine can work together excellently to achieve an improved manufacturing result. The invention thus contributes to an overall process-controlled packaging machine.

The invention also relates to a packaging machine which is in particular in the form of a thermoforming packaging machine, the sealing station of which is designed for producing packaging with a packaging optics which is at least substantially similar to one another and with varying degrees of filling. In addition to the sealing station, the packaging machine according to the invention comprises a control unit which is functionally connected to at least one sensor system designed at the sealing station for detecting a pressure of a packaging volume provided within the sealing station.

According to the invention, the control unit is configured to fill a degree of filling based on a comparison of a time-dependent, at least temporarily preferably during the filling of the pack volume enclosed within the sealing station between predetermined pressure levels with a time-dependent reference pressure curve stored in the control unit between the predetermined pressure levels known reference volume, and / or to calculate a volume flow with respect to the pressure curve or the reference pressure curve, the control unit also being designed to set at least one process parameter on the packaging machine, taking into account the calculated degree of filling and / or the volume flow.

In the case of the invention, the control unit is designed as a process-controlled sequence control, so that operation of the packaging machine can be adapted excellently to the respective actual measured variables. On the basis of a comparison of the pressure curve with a reference pressure curve provided for the manufacturing situation, the control unit can determine the degree of filling and / or volume flow based on the current pressure curve that can be detected by the sensor and transmitted to the control unit. Based on this, the control unit sets at least one process parameter of at least one further actuator of the packaging machine. From the input signals of the control device depicting the pressure curve, process parameters (control signals) are thus formed as output signals in accordance with a control algorithm for carrying out the above-mentioned comparison, which parameters are applied via actuators to a control object (technological process, control path) provided on the packaging machine, for example to at least one work process on the Sealing station, act.

Figur 1

eine schematische Ansicht einer bekannten Siegelstation;

Figur 2

eine Verpackungsmaschine, die in Form einer Tiefziehverpackungsmaschine ausgebildet ist, an welcher die Erfindung zum Einsatz kommt;

Figur 3

eine schematische Darstellung der erfindungsgemäßen Siegelstation mit verbundener Steuereinheit zum Durchführen der erfindungsgemäßen Verfahrensschritte; und

Figur 4

eine schematische Darstellung des erfindungsgemäßen Verfahrens.

The prior art and embodiments of the invention are explained in more detail below with reference to the figures. Show:

Figure 1

a schematic view of a known sealing station;

Figure 2

a packaging machine which is designed in the form of a thermoforming packaging machine on which the invention is used;

Figure 3

a schematic representation of the sealing station according to the invention with a connected control unit for performing the method steps according to the invention; and

Figure 4

a schematic representation of the method according to the invention.

Fig. 1 shows a schematic representation of a sealing station S 'according to the prior art.

The sealing station S 'has a sealing tool upper part SO' and a sealing tool lower part SU 'which can be closed with the sealing tool upper part SO' and is designed to accommodate preformed packaging trays VM '. In the in Fig. 1 Packaging troughs VM 'shown include packaging contents I', ie products, whose filling levels FG 'are different.

In Figure 1 The sealing station S 'forms a sealing chamber SK', in which the packaging troughs VM ', together with an upper film O' positioned above them, enclose an airtight packing volume P 'which consists of a partial volume V1' and a partial volume V2 '. The partial volume V1 'is composed of the sum of the respective packaging tray volumes created by the packaging trays VM' and released by the products. The partial volume V2 'forms an imaginary partial volume which is enclosed between the upper film O' and an imaginary plane E 'shown in broken lines. On the basis of the sub-volume V2 ', a connecting gap SP' is formed above the packaging trough VM ', which allows the gas G' to be distributed within the entire packaging volume P ', in particular during the filling process.

According to Fig. 1 a sealing tool SW ', for example a height-adjustable sealing frame, is positioned within the upper sealing tool part SO' for a sealing process, which is designed to move the upper film O 'for the sealing process by means of a lifting movement H' in the direction of the packaging troughs VM 'provided below.

At the in Fig. 1 shown embodiment, the packing volume P ', consisting of the sum of the respective partial volumes V1', V2 ', is filled to a preset gassing pressure with a gas G' to create a desired atmosphere. The fumigation pressure will conventionally generated from a difference between a gassing target pressure of finished packaging and a preset gas offset pressure. By means of the subsequent stroke movement H ', the sealing tool SW' pushes the gas quantity contained in the partial volume V2 'into the partial volume V1' released from the product contents I 'within the packaging trough VM', so that assuming a homogeneous level distribution, ie not with itself varying filling levels, the gassing target pressure can set in the finished packaging.

As already mentioned in the introduction to the description, however, the respective fill levels of the packaging provided can vary, so that the above offset approach, which, contrary to actual circumstances, is based on the assumption of a homogeneous fill level distribution, leads to the production of optically different packaging.

Fig. 2 shows a schematic view of a packaging machine 1, which is designed in the form of a thermoforming packaging machine T. The packaging machine 1 has a molding station 2, a sealing station 3, a cross cutting device 4 and a longitudinal cutting device 5. These are arranged in this order in a working direction R on a machine frame 6.

On the machine frame 6 of the packaging machine 1, a feed roller 7 is arranged on the input side, from which a lower film U as the lower packaging material 8 is pulled off. The lower film U is transported into the forming station 2 by means of a feed device, not shown. By means of a deep-drawing process taking place there, packaging troughs 14 are formed into the bottom film U by means of the forming station 2. The packaging troughs 14 are then transported further to an insertion section 15, where they can be filled with a product 16 manually or automatically. Following the insertion section 15, the packaging troughs 14 filled with the products 16 are transported further to the sealing station 3. By means of the sealing station 3, the packaging troughs 14 can be sealed with an upper film O, which forms an upper packaging material 10, so that by sealing the upper film O onto the packaging troughs 14, closed packages V are produced, which are made by means of the cross cutting device 4 and the longitudinal cutting device 5 can be separated and transported away by means of a discharge device 13. It may be that empty packaging LV is included in the conveyed goods, for example because of an interruption in the product preparation process.

Furthermore, the in Fig. 2 shown packaging machine 1 via an operator terminal 9, on which process parameters can be set for the respective work stations provided on the packaging machine 1. The operating terminal 9 comprises a control unit 11, which is only shown schematically. The control unit 11 is configured to carry out arithmetic operations, in particular in real time during the manufacturing process, in order to control the packaging machine on a process-based basis, that is to say, if necessary, to initiate an adaptation of the respective process parameters of the packaging machine ,

The control unit 11 is equipped with a sensor system 12 for detecting a pressure P _IST (see Fig. 3 ) one within the sealing station 3 according to Fig. 3 trained pack volume P connected. The sensor unit 12 can be used to continuously transmit current pressure values, ie respective pressure profiles, to the control unit 11 during the gassing and / or evacuation process during the manufacturing process.

Furthermore shows Fig. 2 that the control unit 11 is connected to a schematically represented memory 17, so that it can use reference values stored on it to generate process parameters, in particular to adapt them. For example, it can compare the pressure curve recorded as an input variable at the sealing station 3 by means of the sensor system 12 with a corresponding reference pressure curve of the memory 17, whereby in a first step it uses an algorithm to determine a degree of filling and / or a volume flow and in a further step it is based thereon generates at least one process parameter as an output variable, on the basis of which the manufacturing process can be adapted, so that the packaging machine 1 is able to optimally adapt the manufacturing process running thereon to the respective filling conditions.

Fig. 3 shows the sealing station 3 of the in Fig. 2 shown packaging machine 1 in an isolated representation.

The sealing station 3 comprises an upper sealing tool part 20 and a lower sealing tool part 21, which enclose a sealing chamber 23. Fig. 3 further shows that two packaging troughs 14 with respective products 16 are accommodated in the lower sealing tool part 21, their respective filling degrees 22 differing.

The packaging troughs 14 received within the sealing station 3, together with the upper film O arranged above them, enclose a packaging volume P. The pack volume P is traversed by means of an imaginary plane E, shown in broken lines, whereby it is divided into a sub-volume V1 and a sub-volume V2. The one seen in the image plane on the right A packaging tray 14 with a lower filling level 22 forms a larger proportion of the packaging volume P than the other packaging tray 14 shown to the left with a larger filling level 22.

According to Fig. 3 the partial volume V2 enclosed by the upper film O and the imaginary plane E and the partial volume V1 (free packaging volume P) provided within the packaging troughs 14 can be filled with a gas G via a line 26 and gas pins 29 provided thereon. A gas source Q is provided for the gas supply. An evacuation process can be controlled using a (vacuum) pump VP. Valves 27a, 27b are formed in the line 26 for the filling process and the evacuation process, which valves can in particular be controlled in a process-controlled manner, for example on the basis of recorded pressure values.

A pressure sensor 18 is connected to the line 26 as a sensor system 12 for detecting the pressure P _IST prevailing within the package volume P. The pressure sensor 18 is functionally connected to the control unit 11, which is configured to further calculate the pressure P _IST transmitted to it as an input variable. In particular, the control unit 11 is able to determine the pressure _{curve that is} present on the basis of the detected pressure values P _IST during the filling of the package volume P and to compare this, possibly a section thereof, with a preset reference pressure curve, in order to use this to determine an algorithm based on an algorithm To calculate the degree of filling and / or a volume flow with respect to the packaging V positioned within the sealing station 3, on the basis of which the control unit 11 generates at least one process parameter PP as an output variable.

According to line 26 Figure 3 a collecting volume is connected, which can be used to calculate the packing volume P. Furthermore shows Figure 3 a supply section 30, the volume of which can be eliminated when calculating the degree of filling 22.

Fig. 4 shows a schematic representation of a method using the invention.

First, in a first method step A, the free packing volume P is filled with a gas G via line 26 to create a desired atmosphere.

During the filling according to step A, according to method step B, pressure is detected by means of the sensor 12 within the package volume P. This allows a time-dependent pressure curve 27 for the pressure P _{IST present} within the pack volume P between an initial pressure P1 up to a predetermined gassing pressure P2 to capture. In this case, the control unit 11 can be configured to take into account only a section of the pressure curve 27 for the further method.

According to Fig. 4 the pressure curve 27 recorded in method step B is a linear pressure curve K _IST .

According to the further method step C, a comparison VG of the detected pressure curve 27 with a reference pressure curve 28 takes place. The control unit 11 retrieves the reference pressure curve 28 from the memory 17 for the comparison VG. The control unit 11 can be designed to call up a suitable reference pressure curve 28 with respect to at least one process parameter predetermined for the manufacturing process on the packaging machine 1, in particular at the sealing station 3, from a multiplicity of reference pressure curves 28 provided on the memory 17. According to the reference _pressure curve 28, a time-dependent reference _pressure curve K _{REF is} shown, which would occur in particular when gassing empty packaging LV used for the manufacturing process. To carry out a meaningful comparison and an appropriate derivation of the degree of filling 22, it is advantageous to assume the same volume flow for the respective pressure profiles 27, 28.

After performing step C, i.e. after comparing the respective gradients of the pressure curve 27 and the reference pressure curve 28, the degree of filling 22 and / or the volume flow V becomes in accordance with the subsequent method step D. This is based in particular on the respective for the pressure curve 27 and for the time t and t * elapsed over the reference pressure curve 28, based on the pack volume P and the respective pressure levels P1, P2.

The calculated degree of filling 22 and / or volume flow V can be used by the control unit 11 in a further method step E to calculate at least one process parameter PP. For example, the control unit 11 calculates an offset pressure P _OFF , a gas velocity V _GAS , a valve setting value x and / or triggers a malfunction indicator y based thereon.

Based on the offset pressure P _OFF , the control unit 11 can calculate a pressure P _{RED in} view of a desired gassing _target pressure P _{SOLL of} finished packs V until the filling process A is controlled until it is reached. This is shown schematically in Figure 4 represented by the dash line EZ.

The principle according to the invention can be excellently applied to a process-controlled packaging machine, in which the respective work processes are based on the measurement signal, so that in total both optimal process times and high-quality products can be produced.

Claims (13)

Method for operating a sealing station (3) of a packaging machine (1) for producing packaging (V) with an at least substantially similar packaging optics with possibly varying degrees of filling (22), comprising the following steps: Filling (A) of a free packaging volume (P) enclosed between a lower and an upper packaging material (8, 10) with at least one packaging (V) positioned within the sealing station (3) with a gas (G) intended to create a desired atmosphere from an outlet pressure (P1) prevailing in the package volume (P) to a predetermined gassing pressure (P2), • Detection (B) of a pressure curve (27) at least temporarily during filling (A) of the package volume (P) by means of at least one pressure-sensing sensor (12) connected to it, the pressure curve (27) preferably being based on a time-dependent pressure curve (K _IST ) the outlet pressure (P1) up to the predetermined gassing pressure (P2) is detected, • comparing (C) the recorded pressure curve (27) with a reference pressure curve (28), which is preferably based on a pressure curve (K _REF ), which in turn is time-dependent, for filling a known free reference _{pack volume} (P _REF ) at least one positioned within the sealing station (3), in particular empty reference packaging (V _REF ) with the gas (G) is detected between the initial pressure (P1) up to the predetermined gassing pressure (P2), • Calculate (D) a degree of filling (22) of the packaging (V) positioned within the sealing station (3) based on the comparison of the recorded pressure curve (27) with the reference pressure curve (28), and / or a volume flow (V̇) with respect to the pressure curve (27) or the reference pressure curve (28), and • Setting (E) at least one process parameter (PP) on the packaging machine (1) taking into account the calculated degree of filling (22) and / or the volume flow (V̇). Method according to Claim 1, characterized in that a quotient of a ratio of a time (t, t *) recorded for the pressure curve (27) and a time for the reference pressure curve (28) is subtracted from the whole in order to increase the degree of filling (22) to calculate. Method according to claim 1 or 2, characterized in that the calculation of the degree of filling (22) and / or the volume flow (V Berechnung) is carried out in real time per machine cycle and based on this an automated adjustment of the process parameter (PP) is carried out. Method according to one of the preceding claims, characterized in that the process parameter (PP) is an offset printing (P _OFF ) which is used in and / or in at least one subsequent filling process (A) in order to reduce the packing volume (P) only with gas ( G) until a pressure (P _RED ) is reached, which results from a gassing _target pressure (P _SOLL ) for finished packaging (V) minus the calculated offset pressure (P _OFF ). Method according to claim 4, characterized in that for the calculation of the offset printing (P _OFF ) the Boyle-Mariotte law taking into account a partial volume (V2) of the package volume (P) displaced by a sealing stroke (H) and one in view of the calculated filling degree (22 ) determinable free package volume (V1) including the gassing _target pressure (P _SOLL ) of finished packaging (V) to be produced. Method according to one of the preceding claims, characterized in that the process parameter (PP) is a gas velocity (V _GAS ) which is achieved at the respective gas pins (29) designed to fill the packing volume (P). Method according to one of the preceding claims, characterized in that the process parameter (PP) is a valve setting value (x) which influences an evacuation and / or the gassing process. Method according to one of the preceding claims, characterized in that the process parameter (PP) triggers a malfunction indicator (y) on the packaging machine (1). Method according to one of the preceding claims, characterized in that the free pack volume (P) is connected to a collecting volume (AV) of known size and the free package volume (P) is calculated based on a detected pressure equalization. Method according to one of the preceding claims, characterized in that the process parameter (PP) is continuously set in view of averaged values of the degree of filling (22) and / or the volume flow (V̇). Method according to one of the preceding claims, characterized in that the packing volume (P) filled with gas (G) is formed in such a way that a pressure equalization takes place between several packages (V) positioned within the sealing station (3) during the sealing stroke (H). Method according to one of the preceding claims, characterized in that a supply volume (30) connected to the packing volume (P) is calculated out when calculating the degree of filling (22). Packing machine (1) for producing packagings (V) with a packing optic that is at least substantially similar to one another with possibly varying degrees of filling (22), comprising a sealing station (3) and a control unit (11), which is functionally compatible with one at the sealing station (3) configured sensor system (12) for detecting a pressure (P _IST ) of a pack volume (P) provided within the sealing station (3), characterized in that the control unit (11) is configured to determine a fill level (22) based on a comparison (C) a time-dependent, at least temporarily during filling (A) of the package volume (P) enclosed within the sealing station (3) between predetermined pressure levels (P1, P2) with a time-dependent, between the predetermined pressure levels (P1, P1, P2) P1) stored in the control unit (11) reference pressure curve (28) for filling (A) a known reference volume (V _{R EF} ) and / or to calculate a volume flow (V̇) with respect to the pressure curve (27) or the reference pressure curve (28), the control unit (11) also being designed to record at least one process parameter (PP) on the packaging machine (1) Taking into account the calculated degree of filling (22) and / or the volume flow (V̇).

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