EP1981768B1 - Bag and method for producing the same - Google Patents

Description

The invention relates to a bag according to claim 1 and a bag making method according to claim 18. Sacks are known, which are produced and filled according to the so-called FFS (FFS Form Fill and Seal) method. This procedure is used inter alia in the DE 199 204 78 described. First, in this case, a film tube is unwound from an unwinding device and fed to an FFS machine, in which the film tube is first separated into sacks by transverse cutting welds. These bags are detected by suitable gripping devices, filled in a filling station, closed by another cross-welding and thus discharged as filled and sealed bags from the machine. Furthermore, there has recently been a trend to package ever finer bulk goods in bags. In particular, when the packaging operation of such goods is made by an FFS machine which quickly fills the bag material into the bag, which material may well be exposed to free fall movement by some distance, relatively much ambient air will be packed therefrom Material taken in the bag. This air is initially trapped in the sack by the process of closing the sack.

However, it is an often-pursued goal of experts to vent the interior of the bag and to leave as little air as possible in the bag filling material. For this purpose, bags are usually provided with perforations. However, such perforations or perforations of the bag outer wall have the disadvantage that they lead to leakage, in particular of the fine filling material.

For this reason, the EP 0 768 254 A1 and EP 1 600 399 A1 , which discloses a bag according to the preamble of claim 1, to provide a bag with a vent channel, which is formed of two film layers. The one film layer has first vents to the bag interior and the other second vents to the atmosphere. The object of the present invention is to propose a bag in which the ratio between ventability and possible loss of filling material is improved in the closed state.

This object is achieved in that at least one second venting channel is provided, which is connected to the first channel through second venting openings and which in turn has third venting openings which vent the at least one second venting channel. Such a bag is surprisingly easy to produce.

Among other things, the direct connections of the first venting channel to the atmosphere (perforation of the outer film layer) can often be saved by this measure, without the ventability of the bag falling below the required level. Alternatively, the outer film layer may be provided with a less permeable perforation than the first film layer.

Also, the vent channel of the bag according to the invention is usually formed by a double film layer parallel to the tube axis of the bag. For this purpose, the double layer can already be formed during tube formation. The boundaries of the at least one first venting channel are then advantageously defined by longitudinal welding, which can be introduced by suitable welding devices already in the context of tube formation. If the hose is formed from a flat film by means of a longitudinal weld, then only a second seam running parallel to this first weld is needed to define such a channel. The term venting channel in the sense of the present Registration, however, is to be understood as meaning any manifestation of sack components which are suitable for guiding air from the interior of the sack to further vents, which may well also lead to a further venting channel. In general, such venting channels will have a greater length than width and be formed of double film layers.

According to the invention, at least one second venting channel is provided in addition to the at least one first venting channel. The ordinal numbers first, second and later third vent channel depend on the order in which the air escaping from the interior of the bag flows through the channels on their way into the atmosphere - that is, the outer space. Thus, the at least one second venting duct generally has at least areas without direct connections to the interior of the bag. In this way, the connections to the interior of the bag are spaced from the vents to the atmosphere along the bag surface, which increases the tightness. Direct connections to the interior of the bag are preferably either no longer present in the at least one second venting channel or limited to the areas in which the axes of the first and second channels intersect. The same applies to the third and further venting channels in relation to the second. A venting channel here is an at least partially delimited space.

For example, in the case where at least one first vent channel is parallel to the tube axis and the second is orthogonal thereto, only vents should be in the crossing region of the two channels either from the first to the second or from the second to the third channel or to the atmosphere. If there are vents from the first to the second channel in or near the crossing area, it is advantageous to space the openings from the second to the third channel or to the atmosphere thereof. Optionally, the gusset area can be used for this purpose. Regarding the naming of the vents with ordinal numbers is analogous to the venting channels:

The connection openings between the bag interior and the at least first ventilation channel are the first ventilation openings, the connections between the at least one first ventilation channel to the at least second are the second ventilation openings and so on.

If the at least one first ventilation channel runs parallel to the at least one second ventilation channel, it is advantageous that the longitudinal weld seams required for the formation of the two channels are already introduced into double film layers during tube formation. The vents connecting the first and the second channel should then be designed as interruptions of this weld.

Another advantageous possibility is a largely orthogonal arrangement of the first and second channels to each other. It is clear that manufacturing tolerances, but also acute-angled angles between the channel axes are still covered by the word "largely". It is particularly advantageous to provide channels at a sack end so that a wall or boundary of the relevant channel can already be formed by a final weld. The other wall can then be formed by a transverse weld. Such channels may be first, second or even third venting channels.

The other bag end can be designed in the same way. In general, symmetrical bag designs should be preferred.

For vents come, as already mentioned, interruptions in separating welds in question. Further advantageous vents are holes that can come through punches and perforations to conditions. Often, micro-perforations will be beneficial.

For the purposes of the present invention, "microperforation" is understood to mean above all those perforations whose diameter is smaller than the average or the smallest particle size of the filling material.

In vents filters or valves can be introduced. Filter here means all types of felt-like or stoffartigem material - whether "woven" (woven) or "nonwoven" (non-woven) - understood that on the one hand is permeable to air, but on the other hand dust-like solids can stop.

The production of a bag according to the invention can advantageously be combined with elements of the FFS method in many ways. However, it has been found in experiments to be advantageous that the ventilation ducts extending along the hose axis are already produced during tube formation on a tube former. If then bags with a second are made largely parallel to the first channel extending second vent channel, it is possible to install the necessary transverse seams on the tube former or on the FFS machine. Since the FFS machine works at least partially intermittently, it is better to form the transverse welds here. This can be done by an advantageous (double) welding tool.

Further embodiments of the invention will become apparent from the description and the claims.

Fig. 1

Skizze eines Schlauchstücks 1

Fig. 2

Das Ende eines ersten Ausführungsbeispiels eines erfindungsgemäßen Sackes

Fig. 3

Den Schnitt A-A aus Figur 2

Fig. 4

Das Ende eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Sackes

Fig. 5

Den Schnitt D-D aus Figur 4

Fig. 6

Den Schnitt B-B aus Figur 4

Fig. 7

Den Schnitt C-C aus Figur 4

Fig. 8

Eine Skizze eines Sackes mit zwei parallel laufenden Entlüftungskanälen

Fig. 9

Ein drittes Ausführungsbeispiel eines Sackes 29 mit zwei Entlüftungskanälen 21 und 23

Fig. 10

Ein viertes Ausführungsbeispiel eines Sackes 29 mit zwei Entlüftungskanälen 21 und 23

• Fig. 1 zeigt ein Schlauchstück 101, aus dem ein erfindungsgemäßer Sack 220 gefertigt werden kann. Das Schlauchstück 101 ist durch die erste Längsschweißung 60 aus einer Flachfolie gebildet. Durch die erste Längsschweißung 60 und die zweite Längsschweißung 50 ist der erste Entlüftungskanal 20 gebildet. Die äußere Begrenzungswand 30 dieses Kanals 20 kann im vorliegenden Beispiel nicht gezeigte Mikroperforationen ausweisen. In diesem Fall besitzt die innere Begrenzungswand (auch innere Folienlage) 40 größere Perforationen als die vorgenannten Mikroperforationen. Der Pfeil 70 deutet an, dass Luft durch die vorgenannten Mikroperforationen austreten kann. Das Sackinnere 210 dient der Aufbewahrung von nicht gezeigtem Füllgut.
• Figur 2 zeigt ein Ende eines erfindungsgemäßen Sackes 220. Wieder ist ein erster Entlüftungskanal durch die Längsschweißnähte 50 und 60 gebildet. Dieser erster Kanal mündet über die Entlüftungsöffnungen 90 in den zweiten Entlüftungskanal 140, der durch die Endabschweißung 110 und die zusätzliche Querschweißung 150 gebildet wird. Die zusätzliche Abschweißung 150 übernimmt an den Rändern des Sackes auch die Funktion einer Eckabschweißung 130. Der vorliegende Sack wird vor allem im Bereich der Seitenfalten 80 durch die Nadelung 120, die weit von dem Kreuzungsbereich zwischen erstem 20 und zweitem Kanal 140 entfernt ist, gegen die Atmosphäre entlüftet. Die beiden Kanäle werden durch die Entlüftungsöffnungen 90 und 100 miteinander verbunden. Diese sind durch die Unterbrechung der Schweißnähte 50 und 150 zustande gekommen. Solche Unterbrechungen können durch entsprechend geformte oder gesteuerte Schweißwerkzeuge und/oder eine entsprechende Lackierung der Folienbestandteile, die eben nicht verschweißt werden sollen, zustande kommen.
• Figur 3 zeigt den Schnitt A-A aus Figur 2 aus der durch die Pfeile 160 angegebenen Blickrichtung, wobei Elemente hinter der Schnittebene aus darstellerischen Gründen nicht dargestellt werden konnten. In dieser Schnittdarstellung ist die Wirkung der Unterbrechung der Schweißnaht 50 noch einmal genauer zu sehen. Die Luft strömt dabei entlang des Pfeils 170 aus dem Überlappungsbereich der Begrenzungswände 30 und 40 in den zweiten Entlüftungskanal 140 ein. Entlang der Pfeile 170 und 180 gelangt die Luft dann zu den dritten Entlüftungsöffnungen 120, durch sie dann entlang der Pfeile 190 in die Atmosphäre austritt.
• Figur 4 zeigt ein Sackende, bei dem lediglich die Entlüftungsöffnungen anders gestaltet sind als bei dem in Figur 2 und 3 dargestellten Ausführungsbeispiel, bei dem die Verbindung zwischen dem ersten 20 und dem zweiten Entlüftungskanal 140 von auch als zweite Entlüftungsöffnungen zu bezeichnende Unterbrechungen 90 der Schweißnähte 150 und 50 gebildet wird. In Figur 4 gibt es ebenfalls Unterbrechungen in der Schweißnaht 150, die den ersten Entlüftungskanal 20 bis in den Bereich über dem zweiten Entlüftungskanal 140 ausdehnen. Das Folienmaterial in diesem Überlappbereich zwischen den beiden Entlüftungskanälen 20 und 140 ist durch die Öffnungen 200 durchlöchert, so dass der Kanal 20 durch diese Öffnungen 200 und die Unterbrechungen 90 der Schweißnaht in den zweiten Kanal 140 entlüftet wird (siehe auch Fig. 7). Die schlussendliche Entlüftung des zweiten Kanals 140 zur Atmosphäre erfolgt wieder durch die Nadelung 120.

The individual figures show:

Fig. 1

Sketch of a hose piece 1

Fig. 2

The end of a first embodiment of a bag according to the invention

Fig. 3

The cut AA FIG. 2

Fig. 4

The end of a second embodiment of a bag according to the invention

Fig. 5

The cut DD off FIG. 4

Fig. 6

The cut BB off FIG. 4

Fig. 7

Cut CC FIG. 4

Fig. 8

A sketch of a bag with two parallel ventilation channels

Fig. 9

A third embodiment of a bag 29 with two ventilation channels 21 and 23

Fig. 10

A fourth embodiment of a bag 29 with two ventilation channels 21 and 23

• Fig. 1 shows a piece of tubing 101 from which a bag 220 according to the invention can be made. The tube piece 101 is formed by the first longitudinal weld 60 of a flat film. By the first longitudinal weld 60 and the second longitudinal weld 50, the first vent passage 20 is formed. The outer boundary wall 30 of this channel 20 may identify microperforations not shown in the present example. In this case, has the inner boundary wall (also inner film layer) 40th larger perforations than the aforementioned microperforations. The arrow 70 indicates that air can escape through the aforementioned microperforations. The bag interior 210 is used for storage of not shown contents.
• FIG. 2 shows an end of a bag 220 according to the invention. Again, a first vent channel through the longitudinal welds 50 and 60 is formed. This first channel opens via the vent openings 90 into the second vent channel 140, which is formed by the Endabschweißung 110 and the additional transverse weld 150. The additional Abschweißung 150 takes over at the edges of the bag and the function of a Eckabschweißung 130. The present bag is mainly in the gussets 80 through the needling 120, which is far away from the crossing region between the first 20 and second channel 140, against the Atmosphere vented. The two channels are connected by the vents 90 and 100 together. These are due to the interruption of the welds 50 and 150 come about. Such interruptions can be achieved by appropriately shaped or controlled welding tools and / or a corresponding coating of the film components, which just should not be welded.
• FIG. 3 shows the section AA FIG. 2 from the direction indicated by the arrows 160, with elements behind the cutting plane could not be presented for illustrative reasons. In this sectional view, the effect of the interruption of the weld 50 is shown again in more detail. The air flows along the arrow 170 from the overlapping region of the boundary walls 30 and 40 into the second venting channel 140. Along the arrows 170 and 180, the air then passes to the third vents 120, then exits along the arrows 190 into the atmosphere.
• FIG. 4 shows a sack end, in which only the vents are designed differently than in the FIG. 2 and 3 illustrated embodiment, in which the connection between the first 20 and the second vent passage 140 is formed by also as second vents to be designated interruptions 90 of the welds 150 and 50. In FIG. 4 There are also breaks in the weld 150, which extend the first vent passage 20 into the area above the second vent passage 140. The film material in this overlap area between the two vent channels 20 and 140 is perforated by the openings 200, so that the channel 20 is vented through these openings 200 and the interruptions 90 of the weld in the second channel 140 (see also Fig. 7 ). The final venting of the second channel 140 to atmosphere is again through the needling 120.

The FIGS. 5 to 7 Contain sectional views FIG. 4 , FIG. 5 shows the section DD FIG. 5 merely showing that the second venting channel 140 is arranged between the top seam 11 and the further transverse weld seam 15. In FIG. 6 is the cut BB off FIG. 4 which shows the overlap area between the two venting channels 20 and 140. The openings 200 could again be indicated only by arrow and reference numerals. The reference numeral 210, the bag interior is provided. By the arrow 9, the interruptions of the weld 150 are indicated again. Objects behind the cutting plane were not shown.

In FIG. 7 is the cut CC off FIG. 4 illustrated in which the arrows 260 symbolize the air flows in the second vent channel 140, which come through the air flow through the introduced into the inner boundary wall 40, but not shown here openings 200 to conditions. The Arrows 250 symbolize the flow of air from the outlet openings 120 to the atmosphere.

Of course, both ends of a bag can be equipped with the bag ends shown.

First vent openings For the purposes of the present document, that is to say vent openings which connect the bag interior 210 and the first venting channel 20 to each other, are not shown in the figures for illustrative purposes. Likewise, it was omitted to represent a likewise advantageous needling, perforation or micro-perforation of the outer boundary wall 30 of the first Entlüffungskanals.

FIG. 8 shows a further embodiment of a bag 29 according to the invention, in which two substantially parallel venting channels 20 and 21 are provided, which are bounded by the longitudinal seams 26, 27 and 28. The first vent channel 20 communicates with the interior of the bag via the first vent openings 22 and in turn is vented via the indicated by the rectangle 23 second vent openings 23 in the second vent passage 21. This 21 has vents 24 to the atmosphere. The bag 29 is formed from a piece of hose and closed by Endabschweißungen 22. It is preferably stacked on its area formed by the bag width x and the bag length z (along the tube axis, as is customary in sacks.) When this occurs, a height offset occurs between the first and third vent openings 22 and 24 and the second vent openings 23. LIST OF REFERENCE NUMBERS 101 hose Connector 20 first venting channel 30 outer boundary wall 40 inner boundary wall 50 second longitudinal welding 60 first longitudinal welding 70 Arrow in the direction of the air flow 80 gusset 90 second vents 100 second vents 110 Endabschweißung 120 Needling / punching / third vent 130 corner welding 140 second venting channel 150 Cross weld / additional end weld 160 Arrow in the direction of the section AA 170 Arrow in the direction of the airflow 180 Arrow in the direction of the airflow 190 Arrow in the direction of the airflow 200 second vents / punching 210 Sac interior 220 bag 230 240 250 Arrow in the direction of the airflow 260 Arrow in the direction of the airflow 21 Second, largely parallel to the first 20 running venting channel 22 First vents (sac interior - first channel 2) 23 Second vents between the first and second vent channel 24 Third vents (second channel - outside world) 26 First longitudinal seam 27 Middle longitudinal seam 28 Third longitudinal seam 29 bag 30 boundary wall

Claims (21)

1. Bag (220), which is formed from a tubular film (101) by first transverse weld seams (110, 150), and which bag (220) is provided with at least one first ventilation duct (20) that runs substantially parallel to the axis of the tubular film (101), the inner film layer (40) of which ventilation duct (20) exhibits first ventilation openings for the ventilation of the bag interior (210) into the first ventilation duct (20),
   characterized in that
   at least one second ventilation duct (140) is provided, which is connected to the first ventilation duct (20) by second ventilation openings (90, 100, 200), and said second ventilation duct (140) for its part has third ventilation openings (120) which ventilate the at least one second ventilation duct (140).
2. Bag according to Claim 1,
   characterized in that
   the at least one second ventilation duct (140) extends substantially parallel to the first ventilation duct (20) .
3. Bag according to Claim 1,
   characterized in that
   the at least one second ventilation duct (140) extends substantially orthogonally to the first ventilation duct (20).
4. Bag according to one of the preceding claims,
   characterized in that
   at least one second ventilation duct (140) is provided on at least one end of the bag and that the end block weld (110) of the bag on that end of the bag delimits the at least one second ventilation duct (140).
5. Bag according to the preceding claim,
   characterized in that
   at least one further second ventilation duct (140) is provided on the other end of the bag.
6. Bag according to either of the two preceding claims,
   characterized in that,
   in the direction of the width of the bag (x), the ventilation openings (120) which ventilate the at least one second ventilation duct lie outside the region of the ventilation of the bag interior (210) to the first ventilation duct (20).
7. Bag according to the preceding claim,
   characterized by
   side gussets (80) and in that, in the direction of the width of the bag (x), the third ventilation openings (120) which ventilate the at least one second ventilation duct (140) lie in the region of the side gussets (80).
8. Bag according to one of the three preceding claims,
   characterized in that
   the bag (220) exhibits at least one corner block weld (130) which in the direction of the tubular axis (z), commencing from the bag interior (210), lies in front of the at least one second ventilation duct (140).
9. Bag according to one of the preceding claims,
   characterized in that
   the third ventilation openings (120), which ventilate the at least one second ventilation duct (140), connect the ventilation duct (140) to the atmosphere or to a further third ventilation duct which for its part again exhibits ventilation openings (90, 100, 120, 200).
10. Bag according to one of the preceding claims,
    characterized in that
    at least part of the ventilation openings (90, 100, 120, 200), which ventilate ventilation ducts (20, 140), interrupt a weld seam (50, 60, 110, 150) .
11. Bag according to one of the preceding claims,
    characterized in that
    at least part of the ventilation openings (90, 100, 120, 200), which ventilate ventilation ducts (20, 140) or the bag interior (210), are holes (200) in a film layer (30, 40).
12. Bag according to one of the preceding claims,
    characterized in that
    at least part of the ventilation openings (200), which ventilate ventilation ducts (20, 140) or the bag interior (210), are equipped with filters.
13. Bag according to one of the preceding claims,
    characterized in that
    a second ventilation duct (21) is provided which extends substantially parallel to the first ventilation duct, wherein the first ventilation duct (20) is connected to the second ventilation duct (21) by second ventilation openings (23).
14. Bag according to the preceding claim,
    characterized in that
    at least one of the following groups of ventilation openings (22, 23, 24) is spaced apart from another of the following groups of ventilation openings (22, 23, 24) in the direction of the axis of the bag (z):

    - the first ventilation openings (22)

    - the second ventilation openings (23)

    - the third ventilation openings (24).
15. Bag according to the preceding claim,
    characterized in that
    at least the second (23) and/or third ventilation openings (24) are spaced apart from the first ventilation openings (22) in the direction of the axis of the bag (z) in such a manner that a vertical offset (y) between the first ventilation openings (22) and the second (23) and/or third ventilation openings (24) occurs when the bags are stacked.
16. Bag according to the preceding claim,
    characterized in that
    at least the second ventilation openings (23) are arranged in such a manner that a vertical offset (y) in relation to the first ventilation openings (22) occurs in stacking.
17. Bag according to one of the preceding claims,
    characterized in that
    at least two of the three groups of ventilation openings (22, 23, 24) are spaced apart from one another in such a manner that one of the groups is situated on one end side of the bag and another group on another end side.
18. Method for producing bags according to one of the preceding claims,
    characterized in that

    - a tube is unwound from an unwinding device and fed to a machine which by means of transverse block welds (110) singularizes the tube into tube sections (10),

    - said machine fills the bag (220) which is created in the singularizing process

    - and said machine seals the filled bag by means of a further transverse block weld (110).
19. Method for producing a bag according to Claim 2 or 13 according to the method according to the preceding claim,
    characterized in that
    a tube is unwound from the unwinding device, said tube already exhibiting at least two ventilation ducts (20, 140) located beside one another, said ventilation ducts (20, 140) being arranged substantially parallel to the tube axis.
20. Method for producing a bag according to Claim 3 according to the method according to Claim 18,
    characterized in that
    a tubular film, which exhibits the first ventilation duct (20), is unwound from an unwinding device and fed to a machine which performs transverse welds (110, 150) preferably prior to filling, at least one second ventilation duct (140) being formed by said transverse welds (110, 150).
21. Method according to one of the preceding claims,
    characterized in that
    a tube is unwound which already exhibits at least two ventilation ducts (20, 21) that extend substantially in parallel.

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