HK1058510B - Packaging machine and setting method for the same - Google Patents

Description

Packaging machine and setting method thereof

Technical Field

The invention relates to a packaging machine for the continuous production of sealed packages of a pourable food product and equipped with programmable photocells, and to a method for setting same.

Background

Many pourable food products, such as juice, UHT milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.

A typical example of such a package is the parallelepiped-shaped package for liquid or pourable food products known as Tetra Brik or Tetra Brik Aseptic (registered trademark), which is made by folding and sealing a laminated strip packaging material.

The packaging material has a multilayer construction comprising a layer of fibrous material, e.g. paper, covered on both sides with heat-seal plastic layers, e.g. polyethylene.

In the case of aseptic packages for long-storage products, such as UHT milk, the packaging material also comprises a layer of barrier material, formed for example by an aluminium foil, which is superimposed on a layer of heat-seal plastic material and is in turn covered with another layer of heat-seal plastic material to finally form the inner face of the package containing the food product.

As is known, such packages are manufactured on fully automatic packaging machines, wherein a continuous tubular structure is manufactured from a packaging material supplied in strip form and the strip-shaped packaging material is sterilized on the packaging machine, for example by applying a chemical sterilizing agent, such as a hydroperoxide solution.

After sterilization, the sterilization agent is removed from the surface of the packaging material, for example by evaporation by heating; and the strip packaging material thus sterilized is stored in a closed sterile environment and then folded and sealed longitudinally to form a tubular configuration.

The tubular structure is filled with the sterilized or sterile-processed food product and sealed and cut at equally spaced cross sections to form pillow packs, which are then folded mechanically to form the finished, e.g. substantially parallelepiped-shaped, packages.

Along the way of the strip of packaging material, packaging machines of the above-mentioned type generally comprise a plurality of photocells facing the strip and intended to detect the passage of optically detectable elements, such as optical records or reference codes, in particular bar codes printed on the strip.

These photocells are connected to a control unit for controlling the packaging machine and the control unit acquires the signals generated by the photocells and then, in a known manner, effects the execution of specific operations on the strip of packaging material accordingly.

The photocells currently available on the market are also set themselves to adapt to specific operating conditions by executing teaching programs which can be activated either in local mode, i.e. by the operator pressing a button on the photocell, or in centralized or remote control mode, i.e. by an activation signal from the control unit to an inlet of the photocell.

The teaching program requires that the registration code be advanced past each photocell either manually by an operator advancing the strip of packaging material past each photocell or by applying the registration code printed on a separate layer of paper.

The teaching program provides for automatically setting the photocell operating parameters, which are: for detecting the cursor color (red, green, blue) and the static interference threshold for the passage of the register code on the strip of packaging material.

Despite the great advantages in terms of cost, photovoltaic elements of the above type, when used on packaging machines, cause several drawbacks, namely that they prevent the full exploitation of these available advantages.

In particular, it takes a relatively long time to initiate the local mode of each individual photocell teaching program, since on the one hand a large number of photocells are involved, and in addition the actual position of these photocells on the packaging machine is not always easily accessible by the operator.

Although faster than the local mode, the centralized start-up of the teach-in program cannot be ignored as still involving considerable down-time.

Disclosure of Invention

It is an object of the present invention to provide a packaging machine for continuously producing sealed packages of pourable food products and equipped with an optoelectronic element designed to eliminate the aforementioned drawbacks.

Another object of the present invention is to provide a method of setting photocells on a packaging machine for the continuous manufacture of sealed packages of pourable food products, designed to eliminate the above-mentioned drawbacks.

According to the present invention, there is provided a packaging machine for making sealed packages of pourable food products from a sheet of packaging material; the packaging machine comprises at least one photocell for detecting optically detectable elements located on the packaging material, characterized in that the photocell is externally programmed with respect to its setting parameters.

According to the present invention, there is also provided a method of setting a photocell on a packaging machine for making sealed packages of a pourable food product from a sheet of packaging material; the method is characterized by comprising the step of externally programming the setting parameters of the photoelectric element.

Drawings

A preferred, non-limiting embodiment of the present invention will now be described by way of example with reference to the accompanying drawings. In the drawings:

fig. 1 shows a perspective view of a packaging machine for continuously producing aseptic sealed packages of pourable food products from a tubular structure of packaging material, with parts removed for clarity;

FIG. 2 shows a block diagram of an electrical circuit of an optoelectronic component according to the invention and forming part of the packaging machine of FIG. 1;

figures 3 to 6 show a block diagram of the operational procedure carried out for setting the photocells of the packaging machine of figure 1;

Detailed Description

Number 1 in fig. 1 indicates as a whole a packaging machine 2 for continuously producing sealed packages 2 of pourable food products, such as pasteurized or UHT milk, fruit juices, wines and the like, from a tube 4 of packaging material.

The packaging material has a multilayer structure and comprises a layer of fibrous material, usually paper, covered on both sides with layers of heat-seal material, for example polyethylene.

The tube 4 is made in a known manner not described in detail, i.e. by folding and sealing longitudinally to form a strip 6 of heat-seal laminar packaging material; which is filled with sterilized or sterile-processed food product through a filling duct 8 extending inside the tube 4 and having a flow regulating solenoid valve 10; and the tube 4 is fed by known means along a vertical path a to a forming station 12, where it is cut transversely and folded mechanically to form the packs 2.

The packaging machine also comprises a plurality of photocells 14, which are arranged along the strip 6 of packaging material and are positioned facing the strip 6, also being held in position by respective supports, not shown; and to a control unit 16 for controlling the packaging machine 1.

More precisely, the photocells 14 are arranged in pairs along the strip 6 of packaging material in order to read the pairs of recorded codes side by side on the strip 6. For simplicity, however, fig. 1 shows only two optoelectronic elements 14 forming part of different pairs.

The photocell operating parameters can be configured either in a remote control mode, i.e. by means of a signal from the control unit to an entry on the photocell or by means of implementing a teaching program; it can also be realized in a local (local) mode, i.e. by the operator pressing a button of the photocell, or in a centralized or remote control mode, i.e. by means of an activation signal from the control unit to said entrance of the photocell.

These measures provide for automatically or self-setting parameters of the operation of the photocell: for detecting the color of the passing light spot (red, green, blue) registering the code on the strip of packaging material; a static interference threshold; a dynamic interference threshold; a static or dynamic photoelectric mode of operation whereby the passage of a recording code is detected by comparing the level of the photoelectric element signal with a static interference threshold or by comparing the value of the change in the photoelectric element signal with a dynamic interference threshold, respectively; signal offset (degree) for calculating the static and dynamic interference thresholds, i.e. the photocell signal level change between the recording code detection and the background detection on which the code is printed; and an activated/deactivated state of the teaching program activation button.

Fig. 2 shows a schematic circuit diagram of one of the optoelectronic components 14.

As shown in fig. 2, the photocell 14 comprises a casing 20 housing a known LED-type light emitting/receiving device 22, not described in detail; a teach pendant start button 24; a microprocessor 26 connected to the light emitting/receiving means 22 and to the actuation button 24 and having a corresponding memory 28, and an input/output interface 30 connected to the microprocessor 26 and to the control unit 16 and allowing the exchange of two-way data and signals between the microprocessor 26 and the control unit 16; this will be described in detail later.

The memory 28 stores the above-mentioned photocell setting parameters: for detecting the color of the light spot through which the recording code passes; the static or dynamic interference threshold; electrostatic or dynamic modes of operation; signal offset; and the state of start/stop of the start button 24.

The memory 28 may also store data relating to photocell operation and operating status, such as total operating time of each LED of the light emitting/receiving device 22, to allow for preventative LED maintenance or to prevent the application of a failed LED.

Suitably, the input/output interface 30 is preferably an RS232 model series communication interface that performs 1200-baud, 8-bit (bit), 1-stop, non-parity procedures and 0-24V dynamic signaling.

The microprocessor 26 is designed to control the operation of the photocell 14 in different programmed operating modes and in particular in an automatic sensing regulation mode; in the locally set mode, this can be achieved either by means of the activation button 24 or by the control unit 16 by means of an activation signal provided by the input/output interface 30; and by means of which the photocells are set directly by the control unit 16 via the input/output interface 30 in different centralized or remote setting modes, as will be explained in detail later on with reference to the flow diagrams of fig. 3-6.

The flow chart of fig. 3 illustrates the operation with respect to the first photocell setting mode, which is performed when the reference to the strip 6 of packaging material is known in advance.

More precisely, in this first setting mode, the operator, starting from a data input device, for example a keyboard or a selector, with which the packaging machine 1 is generally equipped, first inputs into the control unit 16 the feeding speed and the colour of the strip 6 of packaging material and the recording of the coded colour on the strip 6, or one or more sets of preset parameters (block 50).

On the basis of the operator input strip parameters, the control unit 16 then calculates the setting parameters of the photocell 14: in the example shown, the dynamic interference threshold and the spot color (box 60).

At this point, the control unit 16 uploads, i.e. provides, the photocell 14 with the calculated setting parameters, which are obtained by the corresponding microprocessor 26 via the corresponding input/output interface 30 and stored in the corresponding memory 28 (block 70).

Finally, the microprocessor 26 sets the respective photocell 14 to a static or dynamic mode of operation as a function of the upload setting parameters (block 80). In the example shown, a dynamic interference threshold is input to photocell 14, and microprocessor 26 sets photocell 14 to the dynamic mode of operation.

When the first photocell setting mode operation is completed, the photocell starts detecting the passage of the recording code using the setting parameters.

Fig. 4 shows a block diagram of the operational flow relating to a second photocell setting mode which is performed by the control unit 16 when the parameters of the strip 6 of packaging material are not known in advance.

More precisely, in the second setting mode, the control unit 16 first obtains default photocell setting parameter values, in the present illustrated embodiment the dynamic interference threshold values and preset values of the spot color, which may be stored in the control unit 16 or entered by the operator from a keyboard (block 100).

The control unit 16 then uploads the setting parameters to the photocells 14 (block 110) and the microprocessor 26 sets the respective photocell 14 to the corresponding operating mode (block 120).

At this point, the control unit 16 advances the strip of packaging material 6, starts acquiring from the photocell 14 a signal on the passage of the recorded code on the strip of packaging material 6, and decodes the recorded code (block 130).

The control unit 16 then detects whether the recording code has been correctly interpreted in a known manner not described in detail (block 140).

If the recorded code is correctly interpreted (yes output of block 140), this marks the end of the second photocell setting mode; conversely (no output of block 140), the control unit 16 further detects the photocell setting parameter value (block 150), and the sequence starts again with block 110.

Fig. 5 shows a block diagram of the operational flow relating to a third photocell setting mode which is performed by the control unit 16 when the parameters of the strip 6 of packaging material are not known in advance.

More specifically, in this third setting mode, the control unit 16 first operates the strip of packaging material 6 so as to position the recording code just in front of a specific photocell 14 (block 200).

At this point, the control unit 16 initiates the teach-in routine for that particular photocell 14 by providing an activation signal to the respective microprocessor 26 via the input/output interface 30 (block 210).

At the same time, the control unit 16 runs the strip of packaging material 6 slowly and acquires the signal provided by the particular photocell 14 as to the passage of the recorded code (block 220).

Upon detecting the recorded code pass, the control unit 16 interrupts the teaching program for that particular photocell 14 by providing a stop signal to the respective microprocessor 26 via the input/output interface 30 (block 230).

At this point, control unit 16 downloads the photocell setting parameters, specifically the static interference threshold, the signal offset and the spot color, generated by the teach-in program from the particular photocell 14 (block 240). The control unit 16 processes the downloaded setting parameters and, in particular, calculates the dynamic interference threshold and the spot color (block 250); the calculated setting parameters are then uploaded to all photocells 14 of the packaging machine 1, including the photocell 14 from which the setting parameters were downloaded specifically (block 260).

This marks the end of the third photocell setting mode operation.

Fig. 6 shows a block diagram of the operational flow relating to a fourth photocell setting mode which is performed when the parameters of the strip 6 of packaging material are not known in advance.

In the fourth setting mode, the operator first manually activates the teach pendant for a particular photocell 14 by pressing the corresponding activation button 24 (block 300).

This requires the recorded code to be advanced past the photocell by the operator manually moving the strip of packaging material or applying the recorded code printed on a separate sheet of paper.

Once the teach routine is complete, control unit 16 downloads from the particular photocell 14 the photocell setting parameters generated by the teach routine, specifically the electrostatic interference threshold, the signal offset and the spot color (block 310). The control unit 16 processes the downloaded setting parameters and, in particular, calculates the dynamic interference threshold and the light spot color (block 320) and then uploads the calculated setting parameters to all the photocells 14 of the packaging machine 1, including the particular photocell 14 from which the setting parameters were downloaded (block 330).

This marks the end of the fourth photocell setting mode.

The advantages of the present invention will become apparent from the foregoing description.

In particular, equipping each photocell with an input/output interface allowing the exchange of two-way data and signals between the control unit 16 and the various photocells ensures not only the centralized or remote activation of the program taught by each photocell 14 (as with known photocells), but also the external programming of the setting parameters of the photocells 14 by the control unit 16 and therefore eliminates the aforementioned drawbacks of known photocells.

The invention also ensures the elimination of the drawbacks of the known photovoltaic elements with regard to the printing of strips of packaging material.

This is the case for the known photocells which require the register code to be printed on a white background, which means that, on the one hand, one of the four colours normally used for printing the packaging material strip can only be used for printing the background of the register code, while, on the other hand, white must of course be included in the printing process.

The invention in turn ensures that all the above problems are eliminated, since it allows reading the recorded code on any material or background or even metallized material, and the appropriate spot color and the interference threshold of the photocell are set more simply by the control unit 16.

Furthermore, the above advantages are achieved with relatively small, low cost optoelectronic component variations: the serial input/output interface is, in terms of cost, relatively trivial with respect to the optoelectronic components and can be incorporated in conventional optoelectronic components with little difficulty.

It is clear that several variants may be made to the photovoltaic element illustrated and described above, without departing from the scope of protection of the present invention, as defined in the annexed claims.

Claims (17)

1. A packaging machine (1) for making sealed packages (2) of pourable food products from a sheet of packaging material (6); the packaging machine (1) comprises at least one photocell (14) for detecting optically detectable elements located on the packaging material, characterized in that the photocell (14) is externally programmed with respect to its setting parameters.

2. The packaging machine according to claim 1, characterized by comprising control means (16) connected to said photocell (14); and wherein said photocell (14) comprises input/output means (30) allowing a bidirectional exchange of photocell (14) setting parameters between said control means (16) and said photocell (14).

3. A packaging machine according to claim 2, wherein said input/output means comprise an input/output interface (30) in series.

4. The packaging machine according to any one of the preceding claims, wherein the control means (16) comprise data downloading means (26, 240, 310) for downloading the setting parameters of the photocell (14) from the photocell (14).

5. The packaging machine according to claim 4, characterized in that said control means (16) further comprise data uploading means (26, 260, 330) for uploading set parameters onto said photocell (14).

6. The packaging machine according to claim 1, characterized in that the photocell (14) comprises setting means (26, 210, 300); and wherein activation means (24) are provided for activating said setting means (26, 210, 300).

7. A packaging machine as claimed in any one of claims 1 to 3, characterized by comprising a plurality of said photocells (14); and wherein said control means (16) comprises data downloading means (26, 240, 310) for downloading its setting parameters from a specific one of said photocells (14); and data uploading means (26, 260, 330) for uploading to at least one other optoelectronic component (14) setting parameters related to those downloaded from said optoelectronic component (14).

8. A packaging machine according to claim 7, characterized in that said data uploading means (26, 260, 330) upload said set parameters to all the photocells (14) of the packaging machine (1).

9. The packaging machine according to claim 7, characterized in that at least said specific photocell (14) comprises setting means (26, 210, 300); and wherein activation means (24) are provided for activating said setting means (26, 210, 300).

10. A method of setting a photovoltaic element (14) on a packaging machine (1), the packaging machine (1) being for making sealed packages (2) of a pourable food product from a sheet of packaging material (6); characterized in that it comprises a step of external programming of the setting parameters of said photocell (14).

11. A setting method as claimed in claim 10, characterized in that the programming step comprises the step of providing the photocell (14) with input/output means (30) to allow bidirectional exchange in setting parameters of the photocell (14) between the photocell (14) and the programming means (16).

12. A setting method according to claim 10 or 11, characterized in that said programming step comprises the step of downloading the setting parameters of the photocell (14) from said photocell (14).

13. A setting method as claimed in claim 10, characterized in that the programming step comprises a step of uploading setting parameters onto the optoelectronic component (14).

14. The method of claim 10, wherein the programming step includes the step of controlling the photocell to initiate a setting procedure for the photocell.

15. A setting method as claimed in claim 10 or 11, for a packaging machine (1) comprising a plurality of said photocells (14), characterized in that said programming step comprises the steps of downloading from a specific one of said photocells (14) the setting parameters thereof and uploading to at least one other photocell (14) those setting parameters which are related to the setting parameters downloaded from said specific photocell (14).

16. A setting method as claimed in claim 15, characterized in that said step of uploading to at least one other photocell (14) those setting parameters associated with the setting parameters downloaded from said particular photocell (14) comprises the step of uploading said setting parameters to all photocells (14) of said packaging machine (1).

17. A setting method according to claim 15, characterized in that the programming step further comprises the step of controlling the specific photocell (14) to initiate a setting procedure of the photocell.