Abstract:
The present invention relates to a chamber machine for packaging products in at least one bag, where said chamber machine includes at least one gas nozzle. The chamber machine can also include a monitoring device configured for detecting the presence of a bag neck of the bag over the gas nozzle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority to European Patent Application Number 14190229.6 filed Oct. 24, 2014, to Konrad Möβnang et al. entitled “Chamber Machine with Gas Nozzle Monitoring,” currently pending, the entire disclosure of which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a vacuum chamber machine (i.e. a chamber packaging machine) and to a method of packaging products. 
       BACKGROUND OF THE INVENTION 
       [0003]    European Patent 2 093 147 A1 discloses a belted chamber machine having nozzles that can be introduced into and positioned in bags for gas-flushing a plurality of bags or for allowing a liquid to be injected into these bags. When the bags are placed manually onto the conveyor belt, bags that have not been properly placed may be gas-flushed incorrectly, or not at all, inside the belted chamber machine. In the case of sealed packages having an internal pressure that is similar or equal to the ambient pressure, insufficient gas flushing cannot be detected without using special measurement devices. 
         [0004]    Also, in chamber machines in which the bag is manually pulled over a statically fixed gas nozzle, insufficient gas flushing may result from incorrect handling. In the case of medical products, such errors would lead to high failure costs. 
       SUMMARY OF THE INVENTION 
       [0005]    It is the object of the present invention to provide a chamber machine that is capable of detecting gas-flushing errors. 
         [0006]    The chamber machine according to one embodiment of the present invention can be used for packaging products in at least one bag and can include at least one gas nozzle and a monitoring device configured for detecting the presence of a bag neck of the bag over the gas nozzle. This can allow for reliable detection of a bag that has been inserted incorrectly by hand as well as a bag that has been mispositioned. This is particularly advantageous in a belted chamber machine with automatic bag feeding. Without these reliable detection measures, at least in the case of sealed bags that have been gas-flushed at ambient pressure, it has, up to now, been impossible to recognize whether a sufficient amount of gas has been introduced in the bag or whether gas has been introduced in the bag at all. Validating the packaging process can be of particular importance, especially when medical products are being packed, so that complicated gas measurements of the already sealed bag can be dispensed later on. 
         [0007]    According to one embodiment of the present invention, the monitoring device comprises at least one sensing finger for each gas nozzle, so as to examine on at least one side the presence of a bag pulled over the gas nozzle. 
         [0008]    According to one embodiment of the present invention, each gas nozzle or each sensing finger is adapted to have applied thereto an electric voltage, and the gas nozzle is electrically insulated from each sensing finger. 
         [0009]    According to one embodiment of the present invention, a control unit is provided, which can be configured for applying to a respective gas nozzle an electric voltage, which may be a DC voltage. The control unit can also be configured for detecting a current that flows between the gas nozzle and a sensing finger, or for measuring the voltage across the sensing finger. The presence of a bag over a gas nozzle can thus be examined in a structurally simple and cost-efficient manner. 
         [0010]    According to one embodiment of the present invention, the control unit is configured for indicating an error at a gas nozzle to an operator. The operator can thus be able to sort out the respective bag or to subject it to further examination. 
         [0011]    Two sensing fingers can be provided for each gas nozzle. The sensing fingers can be movable relative to the gas nozzle and relative to one another. The movable nature of the sensing fingers can allow, in a situation in which the whole bag is positioned between only one sensing finger and the gas nozzle without being recognized, prevention of an error by requiring two sides of the bag to be pulled over the gas nozzle. This can further improve process reliability and error checking. 
         [0012]    The sensing fingers can be configured as spring steel sheets, on the one hand for being electrically conductive and on the other hand for applying a slight pressure to the bag and the gas nozzle. This can allow for electric contact in case of an error without damage being caused to the bag. 
         [0013]    According to one embodiment of the present invention, the monitoring device comprises at least one sensor for each gas nozzle. In such an embodiment, the sensor(s) can be an inductive, capacitive or capacitive proximity sensor or an optical sensor. 
         [0014]    According to one embodiment of the present invention, a single sensor is provided for each gas nozzle and the single sensor can be configured so as to detect the inflation behavior of the bag at the respective gas nozzle during the evacuation process and the subsequent gas-flushing process. The single sensor can be a touch switch according to one particular embodiment of the present invention. 
         [0015]    A method according to one embodiment of the present invention used for packaging products in a bag by means of gas-flushing the bag in a chamber machine is characterized in that the position of a bag neck of the bag over a gas nozzle is monitored by means of a monitoring device. In this way, it can be guaranteed that the exchange of gas in the bag is reliably carried out. 
         [0016]    As part of the method, a control unit of the chamber machine can indicate an incorrect position of the bag neck to an operator. 
         [0017]    According to a particular embodiment, the control unit of the chamber machine measures an electric current flowing through the gas nozzle and a sensing finger associated with said gas nozzle, or an electric voltage applied between the gas nozzle and an associated sensing finger. In such an embodiment, the presence of a bag over a gas nozzle can be examined in a structurally simple and cost-efficient manner in this way. 
         [0018]    According to one embodiment of the present invention, the electric circuit is examined directly after closing of a chamber lid or during the gas-flushing process. 
         [0019]    A further step in the method can include execution of an additional examination for validating the electric circuit without a bag being positioned over the gas nozzle, so as to carry out an examination for line fracture of the electric circuits and validate the monitoring device in this way. 
         [0020]    Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description. 
     
    
     
       DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0021]    In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views: 
           [0022]      FIG. 1  is a perspective view of a chamber machine according to one embodiment the present invention; 
           [0023]      FIG. 2  is a perspective view of a monitoring device at an open position according to one embodiment of the present invention; 
           [0024]      FIG. 3  is a perspective view of a monitoring device at a closed position according to one embodiment of the present invention; 
           [0025]      FIG. 4  is a side elevation sectional view of the monitoring device of  FIG. 2  at an open position with an attached bag according to one embodiment of the present invention; and 
           [0026]      FIG. 5  is a side elevation sectional view of the monitoring device  FIG. 3  at a closed position with an attached bag according to one embodiment of the present invention. 
       
    
    
       [0027]    Like components are provided with like reference numerals in all the figures. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purpose of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures. 
         [0029]    The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
         [0030]      FIG. 1  shows a vacuum chamber machine  1  according to one embodiment of the present invention with an open chamber lid  2 , a frame  3 , a chamber base  4  and a plurality of sealing rails  5  on three sides thereof. For packaging a product  6  under a modified atmosphere, the product  6  can be filled into a bag  7  of electrically insulating material and the bag  7  can be placed onto the chamber base  4  in the chamber machine  1  so that the open area of the bag  7 , which still is to be sealed, can rest on or be positioned over the sealing rail  5 . In this position, the open part of the bag  7 , the bag neck  8 , can be pulled over a row of gas nozzles  9 . When the chamber lid  2  has been closed in the direction of the arrow, the interior of the chamber defined between the chamber lid  2  and the chamber base  4  can be evacuated and the bags  7  can be gas-flushed via the gas nozzles  9  prior to hermetically sealing the bags  7  by means of the sealing rails  5 . The chamber lid  2  may be motor driven and activated for closing via a push button  10  or other suitable device. 
         [0031]    The gas nozzles  9  can each include a monitoring device  11 , which can examine whether the bag neck  8  and the bag  7  have been correctly pulled over the gas nozzle  9  or over a plurality of gas nozzles  9 . According to one embodiment, this means that the gas nozzle  9  projects into the bag neck  8  sufficiently far for guaranteeing a reliable gas-flushing of the bag interior. 
         [0032]      FIG. 2  shows the monitoring device  11  at an open position for one and for three gas nozzles  9 , respectively. The monitoring device  11  can comprise an upper sensing finger  12  and a lower sensing finger  13  for each gas nozzle  9 . The upper sensing finger  12  can be attached to a first bar  14  in an electrically insulated manner and the lower sensing finger  13  can be attached to a second bar  15  in an electrically insulated manner. The two bars  14 ,  15  themselves can be, in turn, electrically insulated from the gas nozzles  9  and can be configured so that they are vertically movable by means of guides  16 . A pneumatic cylinder  17  can have a piston rod  18  connected to the second bar  15  and the cylinder body  19  itself can be connected to the first bar  14 . The pneumatic cylinder  17  can cause the first bar  14  and the second bar  15  to move toward and away from each other in a movement relative to one another. 
         [0033]    Making reference to  FIG. 3 , the sequence of movements of the bars  14 ,  15  and of the sensing fingers  12 ,  13 , respectively, will be explained in more detail. The activated pneumatic cylinder  17  can extend its piston rod  18  and, in so doing, push the first bar  14  downwards into contact with a stop  20 . The upper sensing finger  12 , which can be attached to the first bar  14 , can thus be caused to approach the gas nozzle  9  to such an extent that the sensing finger  12 , which can consist of a spring steel sheet, presses against the gas nozzle  9 . As the extension movement of the piston rod  18  continues, the cylinder body  19  can come to rest on the stop  20  via the first bar  14  and also push the second bar  15  with the lower sensing finger  13  into contact with the gas nozzle  9 . At this position, it can be examined whether a bag  7  correctly abuts on the gas nozzle  9  from above with a first side  22  thereof and from below with a second side  21  thereof, as best shown in  FIG. 4 . The bag neck  8  can here be pulled over the gas nozzle  9  at least up to the respective point of contact  23 , as best shown in  FIG. 5 , between the sensing fingers  12 ,  13  and the gas nozzle  9 . 
         [0034]      FIG. 4  shows a sectional view of the monitoring device  11  comprising a single gas nozzle  9 , the two sensing fingers  12 ,  13  and the two bars  14 ,  15 . The two sensing fingers  12 ,  13  and the gas nozzle  9  can each be electrically insulated from one another and each can be connected to a control unit  24 . The control unit  24  can apply a DC voltage, such as 5 V or 24 V or other applicable voltage, to a connection line  30  to the gas nozzle  9  and can measure an electric voltage at the respective connection lines  31 ,  32  to the sensing fingers  12 ,  13 .  FIG. 4  also shows a correctly inserted bag  7  having its bag neck  8  pulled over the gas nozzle  9  so that the first side  22  and the second side  21  of the bag neck  8  project beyond the gas nozzle  9  farther than the point of contact  23  between the sensing fingers  12 ,  13  and the gas nozzle  9  shown in  FIG. 5 . 
         [0035]      FIG. 5  shows the monitoring device  11  at its closed or examination position. In this position the bars  14 ,  15  have been moved apart, the bar  14  can be in contact with the stop  20  and the sensing fingers  12 ,  13  can press against the gas nozzle  9  and the first and second sides  22 ,  21  of the bag neck  8 , respectively. When the first side  22  of the correctly inserted bag neck  8  is positioned between the first sensing finger  12  and the gas nozzle  9 , the control unit  24  can recognize that no current or only a minimum current flows across the gas nozzle  9  having the voltage applied thereto, or that the connection line  31  to the upper sensing finger  12  does not have applied thereto any voltage, since the bag  7 , which can consist of plastic material, can have an insulating effect. This can apply analogously also to the second sensing finger  13 . The control unit  24  can evaluate this result as a correctly inserted bag  7 . 
         [0036]    In the event that at least one side  21 ,  22  has not been pulled over the gas nozzle  9  to a sufficient extent or no bag  7  at all has been inserted, this mispositioning can be detected, since at least one sensing finger  12 ,  13  can be electrically connected to the gas nozzle  9  directly at the point of contact  23  and the control unit  24  can measure the voltage or detect a flow of current at the connection line  31 ,  32  to a sensing finger  12 ,  13  because the insulating effect produced by the bag  7  is missing. The control unit  24  can detect this error and can display it on a display  40  (as shown in  FIG. 1 ) of the control unit  24  of the chamber machine  1 . The operator can thus decide whether a gas-flushed and sealed bag  7  has to be re-examined in some other way or sorted out. 
         [0037]    The monitoring device  11  can also be examined for a fracture of the electric connection lines  31 ,  32  or for contamination of the gas nozzles  9  by moving the sensing fingers  12 ,  13  to the examination position prior to insertion of the bag  7  or after removal of the bag  7  from the chamber machine  1  while the control unit  24  carries out a successful voltage or current measurement. If one of the connection lines  31 ,  32  should be interrupted or if one of the sensing fingers  12 ,  13  should be, for example distorted, the control unit  24  can determine this by means of the monitoring device  11 . 
         [0038]    Another possibility of examination is given during removal of the bags  7 . If the sensing fingers  12 ,  13  still occupy the examination position, a voltage between the sensing fingers  12 ,  13  and the gas nozzles  9  can be measurable at the moment of removal. 
         [0039]    In the event that the chamber machine  1  is configured as a belted chamber machine comprising a conveyor belt and automatically positionable gas nozzles  9 , the above described examination can be carried out automatically prior to feeding new bags  7  or after the discharge of bags  7  that have already been gas-flushed and sealed. 
         [0040]    It is also imaginable that the presence of bags  7  in the chamber machine  1  can be examined by the control unit  24  by means of sensors, preferably light barriers. In this case, only the errors of not correctly inserted bags  7  are likely displayed to the operator by the display  40  and errors caused by the absence of bags  7  are likely neglected by the control unit  24  and not displayed on the display  40 . 
         [0041]    In addition, it is imaginable that gas lines leading to the gas nozzles  9  can be opened by means of valves for the purpose of gas-flushing only if the correct application of a bag  7  has been ascertained for the respective gas nozzles  9 . 
         [0042]    The chamber machine  1  can also comprise a belted chamber machine in which the bags  7  filled with a product  6  are conveyed into the chamber by means of a conveyor belt in alternative embodiments of the present invention. 
         [0043]    From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting. 
         [0044]    The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereto, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.