Patent Publication Number: US-2005121099-A1

Title: Filling bags of film material

Description:
BACKGROUND OF THE INVENTION  
      The invention concerns a method for filling contents into film bags, where film bag items in one continuous web are conveyed through a filling station. The invention furthermore concerns an apparatus for filling contents into film bags, where film bag items are conveyed in a continuous web that includes a channel-shaped opening rim area with bag openings for filling the bags with a liquid fluid when these are passed through a filling station, as the bags after filling are closed and separated from the web. The invention also concerns a packing web for use in the method and in the apparatus.  
      An example of technology for such filling is indicated in EP 0 696 997 in which is specified that the opposite upper edge areas of the bag item web are made with folded, channel-forming rim parts for drawing on guide rods, which in the direction of conveying have a mutual extension for producing opening of the bag items so that these may be filled e.g. through an overlying filling funnel, after which the guide rods are narrowed again towards each other for preliminary closing of the filled bag items. These may then be closed finally by welding below the said duct parts, after which these are cut off and the items are mutually separated. As alternative is specified that instead of the channel parts there may be used edge thickenings that may be received in slotted guide tubes for quite corresponding conveying of the bag items. This technique is not ideal for filling liquid or paste-like fluid into the bags.  
      Furthermore, other forms of means for gripping and carrying the opposite upper edges of the bag item web have been proposed, e.g. as indicated in EP 0 555 321, where special gripping chains are used for the purpose, without special requirements for the design of the upper edge areas of the folded bag item web. This is of particular significance in that a simple rolled up flat film web without local thickenings may be used as starting material, but on the other hand there are considerable problems, both with regard to filling liquids and the guiding of the opposite bag item edges for secure engagement with the gripper chains and with regard to a desirably cheap design of these chains.  
      In EP 0 396 838 and EP 0 825 116 is indicated working with a closed flat tube web of the film which running may be cut along its upper edge with associated integrated unfolding and gripping of the upper edges thus cut up without these being particularly designed neither as ducts nor with thickenings, which would signify a marked simplification of the requirements for formation of the bag web. The cut up upper edge parts are unfolded for clamping between respective moved belts, which are formed with longitudinal recesses, and corresponding cords for pressing in, whereby a suitably firm carrying engagement can be established. Furthermore, there is a risk of product penetrating down into the belts of the driving arrangement etc. Also, there is risk of axial displacement of web material, which can cause formation of folds and problems with welding problems coming thereof.  
      This engagement, however, is not more firm than axial slipping may occur between the upper edges of the bag web and associated belt conveyor means, whereby uncertainty may arise as to whether a conveyed item has been conveyed entirely synchronously with the conveyor belts. Furthermore, deviations with regard to level of the area of the web sides clamped between the conveyor belts may arise, which can have significance to whether the filled bags are finally closed just on the spot intended for this purpose, e.g. with regard to print on the bag. Finally, this technique will not be suited either for use in filling liquid or pasta-like fluid into the bags.  
      It is the purpose of the present invention to indicate a method, an apparatus and a packing item that relieve the disadvantages of the prior art, and which enable filling film bags in a simple way with a liquid or pasta-like fluid, preferably so that each bag contains a well-defined volume and which furthermore can establish a firm a well-defined carrying engagement during filling and welding.  
      According to the present invention, this is achieved with a method of the type mentioned in the introduction, which is peculiar in that a mandrel is successively guided into a channel-shaped opening rim area of the web of coherent film bag items, whereby bag openings are opened for receiving the contents, as the bags via the mandrel are filled with a liquid fluid and are then closed and separated from the web, and that squeezing of the channel-shaped area of the channel-shaped opening rim area around the mandrel is established at opposite sides of one or more bag openings for a bag, that the filling is established through one or more openings in the mandrel by displacing a well-defined volume through one or more ducts in the mandrel.  
      The apparatus according to the invention is peculiar in that the filling station includes a mandrel for successive guiding coherent film bag items of the web into the channel-shaped opening rim area, whereby the bag openings are opened for receiving the fluid and squeeze means disposed at opposite sides of one or more bag openings for a bag, and which are adapted for squeezing around the mandrel with the channel-shaped opening rim area disposed around the mandrel opposite to one or more openings that are established in the mandrel, and which through one or more ducts in the mandrel are connected with means for displacing a well-defined volume.  
      The packing web according to the invention is designed with a continuous row of flat bag items, the web including along a top edge a channel-shaped opening rim area that communicates with bag openings for receiving a content in use, as the bags via a mandrel inserted into the channel-shaped opening rim area are filled with liquid fluid and then is closed and separated from the web.  
      In a special embodiment, the packing web will be peculiar in that the rim strip areas are constituted by a simple extension of the bag side.  
      By the present invention it has appeared possible to achieve a simple filling of film bags that are unrolled from a continuous web, by the filling station including a mandrel that is simultaneously used for supporting the web of film bag items and for filling the bags with a liquid fluid. As the bags are filled directly through duct, there is no risk that the fluid penetrates into the driving arrangement. The liquid fluid is pressed via internal ducts in the mandrel out through openings formed in the circumferential surface of the mandrel, and which communicate with one or more ducts in the mandrel, and which are aligned with the bag opening in a filling situation where the squeeze means are squeezing the channel shaped opening rim area around the mandrel, whereby the fluid may only flow into an associated bag through one or more openings connecting the interior of the bag with the closed duct length between two successive squeeze means.  
      It is possible to have several juxtaposed openings in the mandrel which is aligned with one or more corresponding bag openings for a bag. One or more ducts inside the mandrel is/are connected with each their displacement pump or corresponding element that is capable of supplying a well-defined fluid volume corresponding to the volume desired to be filled into the bag.  
      By using the apparatus and method according to the invention, a mandrel penetrating into the channel-shaped opening rim area is to open this duct where opposite sides will be in close contact. At the start of fluid filling, filling of the part of the duct surrounding the mandrel will occur very quickly. After that, a well-defined volume introduced through the mandrel will thus fill the bag disposed opposite to the filling opening of the mandrel. Thus it is also possible to avoid the risk of air being filled into the bag, which may be advantageous for durability both for the product and for the bag itself.  
      If the mandrel contains several ducts that are connected with the associated filling openings, it is possible by a simple filling sequence to fill several juxtaposed bags which are disposed opposite to associated filling openings in the mandrel. As clamping is established where the channel-shaped opening rim area is clamped around the mandrel, fluid introduced through the duct will necessarily be filled into the bag without risk of air being confined or letting out fluid, which mean insufficient filling of the bag.  
      The clamping is preferably established by the film being squeezed between displacing elastic jaws and the surface of the mandrel. The jaws may be displaced by pivoting or a translational displacement. The jaws only need an elastic surface, e.g. in the form of a rubber coating on metal jaws. Hereby is achieved a secure closing even if tolerances occur between jaws and associated mandrel.  
      However, it is preferred that there are provided well-defined interacting surfaces on the mandrel. Such interacting surfaces may e.g. be constituted by slightly elevated parts. Such slightly elevated parts may, in case of largely cylindric mandrels, be constituted by bushings that are used for assembling successive tubular parts of the mandrel. By such an assembling method it is possible at the same time to provide more concentric pipes within the mandrel, so that each concentric pipe opens at a tubular section of the mandrel which is placed between two assembly bushings.  
      By the method is provided secure filling of the bags, whereby risk of confining air is avoided, which can give rise to decomposition of the fluid products. When the case is liquids like water, juice, dairy products and the like, it is possible to perform welding of the bag opening so that penetration of air into the bag does not occur at the closing, and thereby confining of air in the filled bag is also avoided.  
      According to a particular embodiment for low-viscosity fluid, it is preferred that the filling occurs with an upwards directed flow of fluid through upwards directed openings. Hereby is achieved that fluid is running out of the mandrel and thereby contribute to an uncertain volume at the filling of each individual bag.  
      According to an alternative embodiment by filling oil- or fat-containing liquid or paste-like fluids, it is preferred that filling occurs by downwards directed flow of fluid through downwards directed apertures that are directly aligned with bag openings. This will particularly take place by air being allowed access to the interior of the bag web in order to enable an opening without formation of vacuum. Therefore, there will either be openings in the web material or air ducts in the mandrel and use of vacuum nozzles for pulling the webs of material away from each other to form a distended bag opening. Hereby, contact between the fluid and the rim areas of the bag opening, which are welded subsequently, may be avoided. By filling such oil- and fat-containing fluids it will also be possible to provide a bag filling and subsequent closing of bags by welding.  
      Even if it is preferred that the bag openings are welded after filling in order to close the bags, it is possible to use alternative methods for closing the bags, e.g. by applying a glue strip.  
      After the bags have been closed it is possible to remove exceeding parts of the rim strip areas by cutting. Hereby is achieved a film bag where the rim strip area, which has formed the channel-shaped opening rim area, is removed after filling. According to a further embodiment of the invention, the method is peculiar in that the bag web is cut up, and the cut free rim strip areas thereby formed are brought into connection with pressing rollers that are arranged downstream of the mandrel, and which are arranged for squeezing around the rim strip areas, whereby the channel-shaped opening mouth areas of the bag web is drawn over the mandrel. By this method is achieved a simple and secure drawing of the bag web over the mandrel.  
      It is also possible to fill bags having a channel-shaped extension or filling opening. In such a bag, besides rim strip areas, parts of the bag web disposed at the sides of the channel-shaped filling opening will also be cut free.  
      Correct indexing and thereby correct positioning of the bag openings in relation to associated filling openings in the mandrel can be achieved by using index means in the shape of photo cells that detect holes or colour codes in the bag web and which, via a control unit, are connected to motors for driving the pressing rollers. The pressing rollers shall have a speed which is synchronised with the driving speed for further guide means in the shape of endless opposite parallel conveyor runs constituting a part of the transport line.  
      The packing web according to the invention may be provided in rolled up state, as it appears as flat bag items with uniform thickness across the entire width. This enables easy handling of material webs that may be provided with considerable lengths, whereby long-time intermittent filling of bags is possible. Alternatively, it is possible to provide the webs of material from a folded supply as alternative to the rolled up supply. Also by such folded supply there will be uniform thickness, giving handling advantages in relation to material webs where different thickness appears transversely of the material webs. Alternatively, in a folded supply there may be used bag items that do not have uniform thickness, as for example bags with zip closure.  
      According to a particular embodiment, the packing webs are peculiar in that it is made with prepared film bag items extending in from one side edge until a distance from the opposite side edge.  
      By such packing webs, the flat bag items will already be completely or partly divided in advance, which is easier than the subsequent separation which in principle can be effected by cutting off the unbroken rim strip areas appearing between the opposite side edges of the web and the bag openings that are welded. By-rolling up, bags will cohere for easy winding. Therefore, the bags will be connected at certain points or at perforations so that they are only partly divided, but may be readily separated anyway by filling. In this way, welding and cutting up may occur in the same operation after which the bags appear separated for subsequent handling in packing equipment.  
      It is to be mentioned that the packing web may be designed as a bag which is divided as a large compartment which is only provided along edge areas at the bottom, side edges and a part of the top for leaving a bag opening.  
      Alternatively, the bags may be designed with a plurality of weldings between the side edges for dividing the bag into a number of chambers that are mutually connected, and to which access is provided through several juxtaposed bag openings that are juxtaposed at the top of the bag in a side in the channel-shaped opening rim area.  
      Alternatively, the bags of the packing web may be designed with one or more inlet ducts connecting the channel-shaped rim strip area with the interior of the bag. 
    
    
     DESCRIPTION OF THE DRAWING  
      The invention is explained in detail in the following with reference to the accompanying drawing where:  
       FIG. 1  shows a schematic perspective view of an apparatus according to the invention,  
       FIG. 2  shows a partial side view of the apparatus shown in  FIG. 1 ,  
       FIGS. 3-5  show a mandrel for use in the apparatus, seen from different sides, and  
       FIGS. 6-8  show different alternative packing webs.  
    
    
      On  FIG. 1  of the drawing is shown that from a supply roll  2  a film material web  4  may be unrolled which consists of a double film folded around a bottom edge  6  and joined at the edge along the upper edge by a simple welding  8 , without any foldings or thickenings of any kind. Therefore, it may also be a tubular film.  
      In the web there may occur a series of slots  10  that extend from the bottom edge  6  at a distance under the top edge  8 , so that the web appears with mutually separate bag items  12 , the side edges of which are closed by weldings  14 . Right over the top of the slits  10 , the double web is cut along a horizontal line  16 .  
      It is also important that it is ensured that a channel-shaped opening rim area  38  at the upper side of the web is formed in connection with bag openings  40  that are intended to receive a liquid or pasta-like fluid which is filled into the bag.  
      As it appears from  FIGS. 1 and 2 , this previously prepared web  4 , rather than being better rolled up may appear in a supply box in zigzag folded form, will be threaded into a filling station  34  that include a mandrel or rail  20  extending from a fixed frame part  22  of the unit and which is hollow and serve to be inserted in the channel-shaped opening rim area  38 , whereby the channel-shape opening area is opened. At the insertion of the mandrel  20 , openings  42  in the surface of the mandrel (see  FIG. 5 ) are brought to correspond to the bag openings  40 .  
      As it further appears from  FIGS. 3-5 , the openings  42  of the mandrel communicate with concentrically disposed, internal ducts  44 ,  46 . The ducts  44 ,  46  open into mandrel sections  45  and  47 , respectively. At each end of the sections  45 ,  47  there are provided bushings  49  that are used for assembling pipe sections and which at their upper side have surfaces  50  interacting with displacing elastic jaws  48 . The jaws  48  are provided on a common frame  51  that may be pivoted back and forth for squeezing against the surfaces  50  on the mandrel with the channel-shaped opening rim area  38  disposed therebetween. Hereby are formed closed compartments ensuring that liquid from the openings  42  of the mandrel is led down into the bags  12 .  
      Furthermore, it is to be mentioned that by filling the two ducts  44 , 46 , supply ducts  56 ,  58  connected with each their displacement pump or piston  60  and  62 , respectively, are used.  
      As it particularly appears from  FIGS. 1 and 2 , at a small distance in front of the connection of the supply pipe  56  to the mandrel, the mandrel  20  has an upwards projecting knife member  24  that by advancing the web  4  will cut the upper edge  8  thereof con-currently, and a horizontal knife member  32  that is cutting the channel-shaped opening rim area  38  from the bags  12  at the cutting line  16 , whereby rim strip areas  54  are formed, passing at both sides of the supply pipes  56 ,  58 .  
      The rim strip areas  54  are then brought around rollers  25  and guide means in the shape of pressing rollers  26  pressing around the rim strip areas  54 , thereby advancing the bag web over the mandrel. Furthermore, there is arranged a support system for carrying on, consisting of opposite, parallel conveyor runs  30  in the shape of tooth belts that are pressed into engaging opposite side edges at the upper side of the bags at a position immediately below the welding  31  closing the bags. These runs  30  are arranged in order to support the weight of the filled bags  12  and are disposed around reversing wheels  33 ,  35 , of which the first wheel  33  is disposed so that the filled bags  12  are supported before they are separated from the support on the mandrel  20  by the knife elements  24 ,  32 .  
      By operating the pressing rollers  26 , the channel-shaped opening rim area  38  is drawn in over the mandrel  20 .  
      By a weld closure is used a welder  36  including two jaws  37  that are moved against opposite sides of the bag items in order to weld the bag openings  40  together. This occurs e.g. immediately under the top of the slits  10 . In the shown embodiment, the welder  36  is disposed after the knives  24 ,  32 . Alternatively, the welder may be provided before the knife so that there may be performed a subsequent cutting of and releasing of the filled and closed bags from the rims strip areas  54  of the web which are then rolled up as excess.  
      The pumps  60 ,  62  used may at each stepwise advancing of the bag web fill two juxtaposed bags that are disposed opposite the sections  45  and  47 , respectively, which is FIG. in  FIG. 2 . This filling is effected with the jaws  48  in squeezing abutment against the surfaces  50  (see  FIGS. 3-5 ), whereby advancing of fluid/liquid from each of the two displacement pumps  60 ,  62  is provided to each juxtaposed bag. It is possible to fill several juxtaposed bags by having several concentric tubes inside each other. However, in such a situation the mandrel may become disproportionately long.  
      Alternatively, for using concentric tubes for forming the ducts  44 ,  46 , it is possible to use parallel tubes that discharge into each of the juxtaposed sections  45 ,  47 .  
      It is possible to provide the ducts with liquid from the same container or with different types of liquid if it is desired to fill juxtaposed film bags  12  with different content. E.g. it may be possible to provide essence in one bag and water in a juxtaposed bag, or alternatively, it is possible to provide a base product and a substrate in a subsequent bag.  
      In the shown embodiment, the channel-shaped opening rim area  38  is separated at the intrusion of the mandrel  20 . Alternatively, it is possible to assist this opening by using vacuum nozzles that draw the bag sides apart at the insertion of the mandrel. As mentioned above, this occurs in a method allowing access of air, either via duct in the mandrel or via openings in the bag sides, to the interior of the bag for enabling opening of the bag openings  40 .  
      Furthermore, it is also to be mentioned that by filling with low viscosity liquid, it is preferred that the openings  42  are facing upwards, whereas by filling-with high viscosity liquids or pasta-like products the openings will face downwards and be directly aligned with the bag openings  40  in order to avoid oil-containing and pasta-like products coming in contact with the bag sides, thereby preventing welding. There will be a separation of the bag sides in order to open the bag openings  40  as described above. If the openings face downwards, it is preferred by the filling that displacement pumps or pistons are performing a short return movement in order thereby to avoid dripping after the filling has been terminated.  
      Furthermore, it is to be noted that subsequent bags  12  do not need to have the same width. It is possible to use bags with different width and thereby with different volume content. This may be advantageous when filling different substances in succeeding bags  12 .  
      With an apparatus as describe above, it is very easy to perform changing for filling different bag types. The mandrel  20  can be exchanged in a simple way in order thereby to be adapted to new bag width and/or dimension on the opening rim area  38 . The mandrel  20  may thus be provided with bayonet sockets on the fixed support part  22 . Furthermore, the squeeze jaws  48  may be disposed displacing in the longitudinal direction of the mandrel, so that they may easily be adjusted to different distance between the interacting surfaces  50 .  
      In  FIGS. 6-8  are illustrated different examples of packing-webs that contain different bag types  12  which via the channel-shaped opening rim area  38  are supported by the mandrel  20 .  
      In  FIG. 6  is illustrated a bag  12  in which is provided three juxtaposed bag openings  40  that each are communicating with the channel-shaped opening rim area  38 . The bags  12  are made with opposite bag sides, partly welded together at punctiform vertical weldings  13  and punctiform horizontal weldings  15 . Hereby the bag is produced with a number of chambers  12 ′ that are mutually connected, and which enables making of a filled bag having a relatively flat shape and which e.g. may be used for making ice cubes.  
      In  FIG. 7  is illustrated a bag  12  having one bag mouth  40  extending over largely the entire width of the bag. Each bag has one large chamber and is only closed at bottom, side edges and top as described in connection with web shown in  FIG. 1 .  
      In  FIG. 8  is illustrated a bag  12  provided with a channel-shaped filling opening  17  where the bag opening  40  communicates with the channel-shaped opening rim area. When the bag  12  is cut free, parts  19  at each side of the channel-shape filling opening  17  are also cut free.  
      A bag may, as alternative to the above shown types, also be formed as a standing bottom bag, e.g. for juice, dairy products and the like.