Abstract:
A packaging plant comprises several test stations as well as a transport system and a control system. The control system is configured to manage packages which are transported in the packaging plant on the transport system along the test stations such that a status is assigned on each package by the control system which can be changed by the test stations together with the control system. A discharge station for defective packages is arranged in the direction of production downstream of at least two test stations. The status of the packages can be changed by at least two test stations to be passed one after the other, and the packages can be marked by a marking means corresponding to their status.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims foreign priority benefits under 35 U.S.C. §119(a)-(d) to German patent application number DE 102010004630.2, filed Jan. 14, 2010, which is incorporated by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to a packaging plant as well as to a method for operating a packaging plant. 
       BACKGROUND 
       [0003]    Packaging plants usually comprise several workstations. At the beginning of a packaging plant, containers can be transferred to a transport system where the transport system is in most cases configured as a conveying belt. If the containers are first produced within the packaging plant by a shaping station, a film web is moved along the workstations by a film transport chain on both sides. Subsequently, products are introduced into the containers. In a subsequent sealing station, the containers are closed with a lid film after the containers have been evacuated and/or treated with gas to produce a package that ensures maximum storage life, mainly for food. 
         [0004]    If an error occurs, for example in a sealing process, the status of the respective packages is changed in a control system which traces all packages in the packaging plant. The packages have been thereby provided with a status, for example “error”. These packages must be subsequently sorted out as they must not be delivered. 
         [0005]    In the further course of this text, the term “status” will be defined as a virtual condition of the container or the package in the control system. The degree of processing by the workstations is to be understood as the actual condition of the container or the package in the packaging plant. A “container” is open for product supply; a package is defined as an open or closed container, preferably as a container closed by a lid film. 
         [0006]    A next workstation can be a labeling station which applies a label onto all packages. The label can contain the best before date, article number and product information which are usually determined by statutory provisions. 
         [0007]    Packages that have been produced in a deep-drawing packaging machine by a shaping station and are still joined in a coherent film are separated by one or several cutting stations and transported further on one or several tracks. 
         [0008]    Deep-drawing packaging machines are already known in which a machine control system traces the containers or packages across a transport system within the machine from the shaping of containers, filling of products into the containers and closing the containers by sealing a lid film, and applying labels onto the thus produced packages. This means that the position and the status of the container or the package are present in the control system. 
         [0009]    If an error occurs in the workstations for shaping, filling, sealing or labeling, the status of these respective packages is set to “error”. Above all after the deep-drawing packaging machine has been retrofitted, a plurality of empty packages are produced during readjustment. These so-called empty packages should not be fed to the production progress downstream of the deep-drawing packaging machine. This is why these empty packages or the packages with the status “error” are sorted out after the workstation for separating the packages from the coherent film which is situated at the end of each deep-drawing packaging machine. 
         [0010]    In a packaging plant which comprises a deep-drawing packaging machine, for example test stations follow which are designed as independent plant components and take over the packages from a conveying belt, transport these packages through the test stations by means of a conveying belt, and subsequently forward them to a following conveying belt of a following plant component. In such test stations, means such as sliders or air nozzles are provided to discharge packages that are detected as defective into a provided container of the test station. 
         [0011]    Operators of such packaging plants often buy the packaging machines and plant components from various manufacturers. It thus results that each plant component comprises its own discharge system with a receptacle. Here, it is important to at least adjust the conveying belts in the position for transferring the packages and the transport speeds between the packaging machine and between the plant components. Usually, the release for a start of the packaging plant or for stopping the packaging plant is forwarded to the control systems of the respective upstream and downstream plant components by digital signals. 
         [0012]    Here, the test stations work independently and also discharge the packages detected here into a separate receptacle. 
         [0013]    Preferably, the packages are transported, after they have exited from the packaging machine, through a metal detector which checks the packages for metal residues. In case of an error, i.e. the detection of foreign metallic matters in the package, these packages concerned are sorted out into a preferably closable receptacle of this test station by a mechanical slider or by means of air nozzles. It is thus ensured that these packages can only be withdrawn by authorized personnel, usually the personnel responsible for quality, and the operators at the packaging plant cannot feed the products of these packages to the packaging machine again. 
         [0014]    Another test station can be a pair of scales at which packages that are not within the weight tolerance limits are sorted out into a receptacle this station comprises. 
         [0015]    As another test station, a vision system is common to check the presence, the position and/or the correct design of the printing of a label on the package. Here, too, the package is sorted out into a receptacle of this test station in case of an error. 
         [0016]    Thus, by default, many receptacles with sorted out packages are present in series along the packaging plant at the test stations which function as independent plant components. With most of the errors, it is admissible and common to remove the products from the packages again and supply them to the workstation of the packaging machine for filling the containers with the products, because the error of the package is not always related to the quality of the product itself. 
         [0017]    Configuring a packaging plant with several discharge means at the respective workstations or test stations results in a high space requirement for the packaging plant and thus the production area. 
         [0018]    Moreover, the personnel have to cover long distances to empty the receptacles with the discharged packages at the different workstations. 
         [0019]    The operators only identify the reason for the error on the basis of the assignment of the respective receptacle at the respective test station. If packages from different receptacles, and thus with different errors, are unintentionally combined it is no longer possible for the operators to distinguish the packages by their kind of error. 
       SUMMARY 
       [0020]    It is an object of the present disclosure to provide a packaging plant and a method for the operation of such a packaging plant where the above described disadvantages can be eliminated. 
         [0021]    The packaging plant according to the present disclosure can comprise the following workstations and test stations: 
         [0000]    container feed or shaping station for containers,
 
product feed, insertion station or filling station,
 
sealing station,
 
labeling station,
 
cutting or separating station,
 
test station metal detector,
 
test station scales,
 
test station vision system,
 
discharge station,
 
transfer station.
 
         [0022]    The advantage of a discharge station downstream of the test station following a packaging plant is that defective packages can be sorted out at this one discharge station, independent of whether an error was detected at a workstation of the packaging machine or one or several test stations. 
         [0023]    Advantageously, the discharge station also comprises means to apply an optical marking to be able to visually distinguish the packages by the error detected in each case after they have been removed from one or several receptacles. 
         [0024]    A transport system transports the containers or packages through the packaging plant along all workstations and test stations. By means of a control system, all containers and packages are managed within the packaging plant. This means that the information indicating where the containers and packages are situated on the transport system and what is the condition of the containers and packages is present in the control system. In the control system, each container and each package has a status assigned to it by the control system which describes the condition of the container. 
         [0025]    For the further description, the condition of the container or the package is defined as the actual degree of processing by the workstations, and the status as virtual feature for description within the control system. 
         [0026]    The workstations and test stations can change the status of the containers or packages which have been processed by the workstations or checked by the test stations in cooperation with the control system. A container or a package that has already been processed by several workstations can comprise three or more different states (e.g. no error, error 1, error 2) in the control system as several workstations have previously processed the container, and different causes of error and thus different states can exist. It is conceivable that a status which represents the combination of different errors also exists. It is also conceivable that a container or a package where the status has already been changed to “error” is no longer checked by further test stations which it passes. 
         [0027]    The packages can be provided with an optical marking which is preferably carried out directly upstream of or at the discharge station. 
         [0028]    Such a central discharge station following the workstations and test stations does not only have the advantage of one single position in the packaging plant for removing the sorted out packages by operators and/or quality assurance personnel, but also of less required space for the complete packaging plant. If a robot is used for removing the packages from the transport system, the same can replace the individual mechanical sliders at the respective workstations and sort out the packages in a very simple and efficient way into a common or also into several receptacles. 
         [0029]    To allow the personnel to distinguish the packages located in a common receptacle, these can be provided for example with a label upstream of or at the discharge station. This label can contain a text with the status or a color code which corresponds to the status and represents the respective error in a quickly and easily detectable manner. 
         [0030]    For example by an ink jet printer, it is also possible to print a text information or color code directly onto the packages. 
         [0031]    The discharge station is preferably disposed at the end of the packaging plant, at least downstream of the test stations for checking the packages according to different criteria: for example checking for metal residues, wrong weight, wrong or missing label, erroneous print or product residues at the sealed seam. 
         [0032]    Due to statutory provisions, it can be necessary to have several receptacles provided at the central discharge station, one of them having a design which only permits an authorized group of people to remove packages from it because in the food sector, products with metal residues must not be returned to the packaging process. 
         [0033]    According to the method according to the present disclosure, the containers are transported along the workstations, and the workstations forward information to the control system, the latter can lead to changes of the status of a container in the control system. 
         [0034]    In the direction of transport upstream of the discharge station, the packages are optically identified with the status in case of an error during the former processing within the packaging plant, and removed from the transport system in the discharge station. 
         [0035]    By this optical marking, the personnel can visually easily detect which error has occurred in the respective package, be it by a color code or a printed text. 
         [0036]    It is advantageous for the discharge station to have several receptacles for sorting for the different states, as by the different possible errors, different states are also possible which have the common property that the respective packages must be sorted out. 
         [0037]    Below, an advantageous embodiment of the present disclosure will be illustrated more in detail with reference to a drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0038]      FIG. 1  shows a schematic side view of an embodiment of the packaging plant according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]      FIG. 1  shows a packaging plant  1  according to the present disclosure where at the beginning a film web  2  is unwound from a roller  3 , and a shaping station  4  as a first workstation shapes containers  5  for receiving products  6  into the film web  2 . In  FIG. 1 , not all shaped containers  5  are drawn in the film web  2 . An insertion section follows in the direction of production R where a robot  7  inserts the products  6 , which are for example transported on a conveyor belt  8 , into the containers  5 . A next workstation is a sealing station  9  which supplies a lid film  10  (the course of the lid film is not represented more in detail) into the sealing station  9  and seals it with the film web  2  and thus forms closed packages  11  filled with product. In the process, the packages  11  can be evacuated and/or treated with gas before the sealing operation. 
         [0040]    The packages  11  are further transported as coherent film with the film web  2  and in a non-depicted workstation could be provided with a label on their upper and/or bottom side by means of a labeling means. For example, the labeling means could also be a part of a further workstation. The latter is referred to as separating station  12  as at this workstation, the packages  11  are separated from the film web  2  and then leave this separating station  12  one after the other as individual packages  11  on a conveying belt  13 . 
         [0041]    If the products are for example products of the food sector, test stations, such as an X-ray apparatus  14  or a metal detector for checking for foreign metallic matter in the package  11 , and a pair of scales  15  for detecting the weight of the package  11  with the product  6  follow. 
         [0042]    A vision system  16  follows as a further test station which for example checks the position and printing of a label or only the presence of a label. Other test features evaluable by the vision system  16  can also be evaluated. 
         [0043]    At the end of the packaging plant  1 , the individual packages  11  are transferred, for example, into cartons  17  or boxes. In  FIG. 1 , this workstation (transfer station) is configured by a robot  18  which takes the individual packages from the conveying belt  13  and places them into a provided carton  17 . 
         [0044]    One important prerequisite for this is that only packages  11  are introduced into the carton  17  and made available for the further transport path which are in a perfect condition with respect to the product and package including the marking. 
         [0045]    The determination and information whether a product is in a perfect condition or defective is accomplished by means of a continuous-path-control in a control system  19  of the packaging plant  1 . Here, one data record each is assigned to a container or a package within the packaging plant  1 . This data record can contain information, such as the status, cause of defect, position of the container or the package on the transport system within the packaging plant. 
         [0046]    Each workstation and test station  4 ,  7 ,  9 ,  12 ,  13 ,  14 ,  15 ,  16  is connected with the control system  19  and reports, when it identifies an error, the cause of the problem for the respective packages  11 . The control system or the workstation or test station itself thereupon sets another value in the status of the respective container or containers  5  or packages  11 , which are all traced over the complete transport section of the packaging plant  1  and are displayed at an operator terminal  20  preferably graphically and/or with colors. 
         [0047]    The following causes of error can lead to a status “defective” in the respective workstations and test stations: 
         [0000]    Shaping station  4 : 
         [0048]    With an overpressure and/or a vacuum not sufficient for the shaping process, it is not ensured that the troughs  5  exit from the shaping station  4  in a perfect condition. Thus, all troughs contained therein are sent to the control system as being “defective”, and the status is set to “defective—incorrect shaping”. Thereafter, the robot  7  will not place any more products  6  into these troughs. 
       Insertion Section: 
       [0049]    If the robot  7  is not able to fill the provided troughs  5  with products  6 , for example due to a lack of products  6  on the supply belt  8 , the status of the unfilled troughs is changed to “defective—incorrect filling” in the control system  19 . 
       Sealing Station  9 : 
       [0050]    A problem in the gas treatment process with a required gas mixture can lead to an inappropriate atmosphere in the package  11  due to a missing gas type. In such a case, the state of all packages  11  contained in the sealing station  9  is changed to “defective—incorrect gas treatment” in the control system  19 . 
         [0000]    Separating Station  12  with Labeling: 
         [0051]    In case of a lack of labels, for example not all packages can be provided with labels. The status of the packages  11  which have not obtained a label is in this case changed to “defective—incorrect labeling” in the control system  19 . 
       Test Station X-Ray Apparatus  14 : 
       [0052]    Individual packages  11  pass through the tunnel of the X-ray apparatus  14 . If foreign matter is detected in the package  11 , the status of this package is changed to “defective—foreign matter” in the control system  19 . 
       Test Station Scales  15 : 
       [0053]    On the conveying belt of the scales  15 , the weight of the package  11  with the product  6  is determined during the transport movement. For example, with a package with a deficiency in weight outside the predetermined tolerances, here, too, the status of this package is changed to “defective—underweight” in the control system  19 . 
       Test Station Vision System  16 : 
       [0054]    If a missing or incorrectly positioned label or an erroneous printing is evaluated by the vision system, here, too, the status is changed to “defective—vision” in the control system  19 . 
         [0055]    To ensure that no “defective” packages  11  exit from the packaging plant  1 , a central discharge station  21  is provided before the end of the transport section. In  FIG. 1 , the central discharge station  21  is configured by a robot which is able to remove packages from the conveying belt which are set to “defective” via the information of the continuous-path-control  19  and place them into corresponding receptacles  22  or other discharge belts. To be able to distinguish packages  11  which are sorted out due to different causes of error but placed in a common receptacle, a marking means or device  23  is provided by means of which the packages  11  can be lettered, labeled, marked with a color or otherwise optically marked upstream of or at the discharge station  21 . For example, the marking device  23  may comprise a label printing and application device; a printer, such as an ink jet printer, for printing text information and/or a color code directly onto each defective package  11 ; or any other suitable marking device. Furthermore, the marking device  23  may be connected with the control system  19 , or otherwise be in communication with the control system  19 , and may be used to mark each defective package  11  with a mark, such as a letter, label and/or color, that indicates the status of the package and the respective error associated with the package. 
         [0056]    The invention is not restricted to one single central discharge station  21 . Due to statutory provisions, it can also be necessary that in addition an individual test station exists which comprises a separate discharge means where for example the packages are sorted out into a receptacle only accessible to authorized personnel. 
         [0057]    While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.