NZ759032B2 - Ventilatable valve bag - Google Patents

Abstract

ventilatable valve bag (2) made from a wall material (4) with two layers of plastic. The inner layer (6) is gas-permeable but impermeable to the filling material, and the outer layer (8) is gas-impermeable. The bag has two closing sides, with a first closing side (10) formed by folding the wall material, and a second closing side opposite the first closing side. An intermediate space (14) is formed between a part of the inner layer and the outer layer, defining an inner space (12) of the bag . At least one ventilation channel (18) is constructed in an outer side fold (20) of at least one closure side, the channel leading out of a wall material edge section (16) between the inner layer and the outer layer. The invention provides a stable and operationally reliable means for ventilating sacks by arranging the valve mouth away from sealing seams and areas that can be prone to blockage when sacks are stacked upon each other. terial, and a second closing side opposite the first closing side. An intermediate space (14) is formed between a part of the inner layer and the outer layer, defining an inner space (12) of the bag . At least one ventilation channel (18) is constructed in an outer side fold (20) of at least one closure side, the channel leading out of a wall material edge section (16) between the inner layer and the outer layer. The invention provides a stable and operationally reliable means for ventilating sacks by arranging the valve mouth away from sealing seams and areas that can be prone to blockage when sacks are stacked upon each other.

Description

(12) Granted patent specificaon (19) NZ (11) 759032 (13) B2 (47) Publicaon date: 2022.01.28 (54) VENTILATABLE VALVE BAG (51) Internaonal Patent Classificaon(s): B65D 30/08 B65D 33/01 B65D 30/12 B65D 30/24 B65D 30/18 (22) Filing date: (73) Owner(s): 2018.05.23 BISCHOF + KLEIN SE & CO. KG (23) Complete specificaon filing date: (74) Contact: 2018.05.23 PHILLIPS ORMONDE FITZPATRICK (30) Internaonal Priority Data: (72) Inventor(s): DE 20 2017 103 128.4 2017.05.23 REPP, Waldemar (86) Internaonal Applicaon No.: (87) Internaonal Publicaon number: WO/2018/215560 (57) Abstract: A venlatable valve bag (2) made from a wall material (4) with two layers of plasc. The inner layer (6) is gas-permeable but impermeable to the filling material, and the outer layer (8) is gas- impermeable. The bag has two closing sides, with a first closing side (10) formed by folding the wall material, and a second closing side opposite the first closing side. An intermediate space (14) is formed between a part of the inner layer and the outer layer, defining an inner space (12) of the bag . At least one venlaon channel (18) is constructed in an outer side fold (20) of at least one closure side, the channel leading out of a wall material edge secon (16) between the inner layer and the outer layer. The invenon provides a stable and operaonally reliable means for venlang sacks by arranging the valve mouth away from sealing seams and areas that can be prone to blockage when sacks are stacked upon each other.

NZ 759032 B2 Ventilatable valve bag The invention relates to a ventable valve sack having a wall material which comprises at least one inner layer which is permeable to gas and non-permeable to a filling material and at least one outer layer which is non-permeable to gas. The valve sack has two closure sides, wherein a first closure side is formed by closing the sack and a second closure side is arranged facing away from the first closure side. An intermediate space is formed between a portion of the inner layer which delimits a sack inner space and the outer layer.

Such a valve sack is known, for example, from EP 2 186 741 B1. It is used primarily to store and transport powder-like or granular or bulk type and pourable filling material, such as cement or animal feed products. So that the air which is introduced into the sack inner space during filling of the valve sack can subsequently be discharged therefrom, the valve sack can be vented. In the prior art, the valve sack has a ventilation opening in the region of a longitudinal edge which extends as far as a main face of the valve sack and which is constructed as a folding edge, with an interrupted longitudinal sealing seam. In this embodiment of the valve sack, the structure thereof is weakened by the ventilation opening and the necessary interrupted longitudinal sealing seam in a highly loaded region, wherein the folding of the wall material through 180° leads to a considerable expansion or compression of the wall material layers. Furthermore, the ventilation effect is limited in that, during storage of the valve sack, during which generally a plurality of valve sacks are positioned one on the other with the main sides thereof, a mouth opening for the air is blocked by the weight of any valve sacks located thereon. Furthermore, a high resistance to the ventilation is provided by multiple redirection of the air flow between the intermediate space and the environment.

An object of the present invention is to increase the stability of a ventable valve sack and to configure the ventilation in a manner as operationally reliable as possible.

The object is achieved according to the invention in that a ventilation channel is arranged at least at one closure side of the valve sack between the inner layer and the outer layer of a wall material region. This ventilation channel opens from a wall material edge portion in such a manner that the intermediate space is thereby configured to be ventable with respect to the environment. [0004a] According to an aspect of the invention, there is provided a ventable valve sack having a wall material formed from a multi-layered plastic film, the wall material having exactly two layers comprising one inner layer which is permeable to gas and non-permeable to a filling material and an outer layer which is non-permeable to gas and having two closure sides, wherein a first closure side is formed by closing the valve sack and a second closure side is arranged facing away from the first closure side, and wherein an intermediate space is formed between a portion of the inner layer which delimits a sack inner space and the outer layer, characterised in that at least one ventilation channel which opens from a wall material edge portion in such a manner that the intermediate space is thereby configured to be ventable with respect to the environment is arranged at least at one closure side of the valve sack between the inner layer and the outer layer of a wall material region and wherein the ventilation channel is constructed in an outer side fold which forms the first closure side.

As a result of the ventilation channel, the air which has been introduced into the intermediate space from the sack inner space through the inner layer is discharged at the closure side. The sack inner space is the space which is located inside the closed valve sack and which is delimited by the wall material. After the valve sack is filled, the bulk type and pourable filling material is located therein. In this case, a closure side is the side of the valve sack, by the formation of which the sack is closed, wherein a second closure side is arranged parallel with the first side mentioned at the opposite or facing end of the valve sack. The ventilation channel is arranged in a region of the same multi-layered wall material between the inner layer and the outer layer thereof and consequently not between an outer layer of a first wall material portion and the inner layer of an additional wall material portion folded against it.

The inner layer and the outer layer of the wall material which is arranged at the closure side are not connected in a region which extends from the wall material edge as far as the edge of the closure side. The wall material has a substantially planar extent, wherein the thickness thereof is smaller by a multiple than the length of the closure-side and coherent wall material edge thereof. Typically, the wall material is formed from a multi-layered plastics film. The wall material edge describes a surface-area of the wall material, the width of which corresponds to the thickness of the wall material irrespective of the ventilation channel and which delimits an inner main face and an outer main face of the wall material. The wall material edge portion is a coherent portion of the wall material edge, wherein the width of the wall material edge portion is equal to that of the wall material edge.

In that the valve sack according to the invention has the at least one ventilation channel at the closure side, the stability of the valve sack is improved. The closure sides are the least powerfully loaded sides of a valve sack and a discharge of the air at this side produces the greatest possible stability. Both during filling and during storage, any critical stresses act on the wall material which forms the generally larger main sides and/or auxiliary sides of the valve sack. As a result of the arrangement of the ventilation channel, a particularly operationally reliable ventilation of the valve sack is further enabled in that the valve sack can still also be vented when it is filled and closed and stored in a stacked state. As a result of the configuration of the ventilation channel according to the invention, the valve sack can also be further ventilated during such storage.

Preferably, the at least one closure side is configured by folding the wall material. This is the closure side on which the ventilation channel is arranged. The folding of the wall material in order to close the valve sack leads to an increased closure-side stability and reliability of the valve sack. The structural weakening of the wall material by the ventilation channel is compensated for by the folding.

The same closure side is preferably configured by folding the wall material in the manner of a cross bottom. A cross bottom is distinguished in that, starting from an open valve sack, first two mutually opposing corner folds are folded in the direction of the sack inner space. These corner folds do not come into contact with each other.

Subsequently, side folds are formed, in particular from wall material regions which adjoin the main faces of the valve sack, by these wall material regions also being folded. Portions of the side folds are subsequently positioned one on the other and on the corner folds located underneath, whereby after corresponding fixing the valve sack is reliably closed.

The cross bottom increases the stability of the valve sack in the region of the ventilation channel. Inadvertent closure of the ventilation channel as a result of production of stresses in the closure-side wall material is prevented, whereby both the valve sack per se and the ventilation are particularly reliable. An additional advantage of this preferred configuration is the possibility of simple guiding of air between the intermediate space and the environment because the portions of the wall material forming the closure side are each folded only by 90° with respect to the wall material portions which form the main sides and auxiliary sides of the valve sack. At this folding edge, the air flow is redirected only once, which reduces the resistance thereof and makes the ventilation more reliable. Alternatively or additionally, the ventilation channel is delimited by an inner layer which is both arranged on the closure side and which delimits the sack inner space, whereby the inner space can be vented directly into a, for example, ventilation channel at the bottom.

In a particularly preferred manner, the ventilation channel is constructed in an outer side fold which also forms the closure side. The outer side fold is the one of the two side folds which adjoins the inner side fold with respect to the sack inner space. It is referred to as the outer one irrespective of a covering sheet which is possibly fixed to the closure side. In that the ventilation channel extends in the wall material which forms the outer side fold, the air is directed out of the intermediate space into the environment particularly easily because the ventilation channel cannot be closed in a manner dependent on loading by any stress in a superimposed wall material layer.

In an advantageous configuration of the invention, the outer side fold has the wall material edge portion in such a manner that it adjoins the environment. In that the wall material edge portion is located with the mouth opening at the outer side, the air is located in the environment immediately after being discharged from the ventilation channel. In turn, this allows a conventional and particularly stable fixing of the closure side, in which the side folds are adhesively bonded in a planar manner with the corner folds or the inner side fold with the lower sides thereof facing the sack inner space. Furthermore, it minimises the resistance for the air flow in that the air flow is not guided through an additional limited cross-section with resistance. If the outer side fold is adhesively bonded only along an adhesive strip which extends along the side fold edge which adjoins the environment, the ventilation channel extends over a length which corresponds to the width of the wall material edge strip or the adhesive strip. If, starting from wall material edge strips, any coverings of the side fold are present, the ventilation channel is lengthened accordingly.

The valve sack can be produced by closure-side folding of a tubular wall material which is fixed by a longitudinal seam which connects two sides of the wall material. This longitudinal seam extends from one closure-side wall material edge to the other closure-side wall material edge and extends for reasons of stability preferably over one of the main faces of the valve sack. As a result of the better configuration for printing, the main face of the sack facing away from the longitudinal seam is preferably provided with a front side printing which is not disrupted by any seam and which can be seen from above during conventional storage and transport of the sack. In this case, in order to prevent the introduction of foreign bodies as a result of gravitational force, in particular water, into the ventilation channel, the cross bottom is preferably constructed in such a manner that the longitudinal seam extends over the inner side fold of the at least one closure side. It is thereby ensured that, during conventional flat storage, the side fold which includes the ventilation channel is folded downwards from the horizontal, front main face to the rear main face with the longitudinal seam. The opening of the ventilation channel is directed downwards so that an introduction of water via capillary action is also made harder or prevented by the opposing gravitational force.

Preferably, a longitudinal centre axis of the ventilation channel extends substantially parallel with a narrow edge of the at least one closure side. The closure side is delimited by two opposing narrow edges and two wide edges which adjoin them. The narrow edges are located between the closure side and an auxiliary side and are located on the lines at which the corner folds of the closure side adjoin an auxiliary side. However, the wide edge delimits the closure side from a main side of the valve sack.

[0015] In a preferred embodiment, the longitudinal centre axis of the ventilation channel has at each location within the ventilation channel the same spacing with respect to two ventilation channel boundary lines which delimit the ventilation channel transversely to the direction of the air flow at both side thereof. In this case, the ventilation channel can also be delimited by the portions of the outer side fold which do not adjoin the environment and by which the side fold is positioned on the corner folds. The longitudinal centre axis of the ventilation channel intersects with that of the wide edge, as far as which the ventilation channel extends at the closure side, between two auxiliary locations which are arranged on the wide edge and which are displaced in a direction parallel with the narrow edge by a notional displacement of the two boundary locations of the wall material edge portion. The boundary locations form the intersection of the wall material edge and the ventilation boundary lines. The longitudinal centre axis does not necessarily intersect with the wall material edge portion.

[0016] As a result of this extent of the ventilation channel, a path which is as short as possible is ensured for the air flow from the intermediate space to the wall material edge portion. The ventilation of the valve sack can thereby be produced in a particularly operationally reliable manner.

[0017] Preferably, the inner layer and the outer layer are connected to each other on the closure side along a wall material edge strip which adjoins the wall material edge. In this case, the inner layer and the outer layer are not connected only in a portion of the wall material edge strip which directly adjoins the wall material edge portion. The wall material edge strip is a portion of the wall material which adjoins the complete closure-side wall material edge and which in this case has a preferably constant extent in a direction away from the wall material edge. The mouth opening of the ventilation channel is located between the inner layer and the outer layer in the wall material edge portion. This mouth opening and the outermost portion of the ventilation channel adjoining it are delimited laterally, that is to say, at the ventilation channel boundary lines, by the connection of the inner layer and the outer layer in the wall material edge strip.

In this case, this extensive connection of the inner and outer layers in the wall material edge strip is preferably produced before the closure side is folded. In this case, the inner layer and the outer layer are connected to each other along the wall material periphery of the open sack over a predominant portion of the periphery. The connection may be produced in the form of a large number of mutually spaced apart connection locations or in the form of a continuous connection strip. Only the portion of the wall material edge strip through which the ventilation channel leads remains completely disconnected. By the inner layer and the outer layer being connected to the described extent, the stability of the valve sack at the closure side can be further increased. In particular, a relative movement between the inner layer and the outer layer is thereby prevented and the dimensional stability of the closure side is thereby ensured. At the same time, the ventilation channel is constructed in a simple manner.

In a particularly preferred manner, the inner layer and the outer layer are formed from the same material. In that the materials of the inner layer and outer layer are identical, it is possible to select for both layers the material which provides the optimal properties with respect to the stability of the valve sack. The risk of interactions between different materials and particular requirements during the connection of the inner layer and outer layer of different materials can thus be excluded. Generally, the stability of the valve sack can thereby be increased again. In an advantageous embodiment of the invention, the inner layer and the outer layer are primarily, that is to say, by more than 50%, formed from a polyolefin, in particular from polyethylene. This material is distinguished by a particularly high expansibility and impact resistance. These properties make the valve sack particularly robust with respect to environmental influences.

[0020] Preferably, the portion of the inner layer delimiting the sack inner space has ventilation openings. These ventilation openings serve to guide the air from the sack inner space into the intermediate space. The outer layer of the wall material remains free from openings in this case. The ventilation openings, the cross-section of which is smaller than the smallest cross-section of the filling material particles, serve to discharge air from the sack inner space as efficiently as possible. As a result of the number and size of the ventilation openings which can be varied within a broad range, a high total ventilation surface-area which is composed of the cross-sections of the provided ventilation openings at the main faces and auxiliary faces of the valve sack and good adaptation to different filling materials can be produced. Consequently, the ventilation openings allow an increase in the operational reliability of the ventilation with different filling materials.

Preferably, the valve sack has spacer elements which define the intermediate space. These spacer elements ensure that the intermediate space also has a minimum volume if ventilation does not occur and the outer layer is not positioned on a main portion of the inner layer which is provided with openings. This makes the discharge of the air from the sack inner space easier, for example, in the case of ventilation starting again during storage, in that the outer layer cannot be applied to the inner layer in a planar manner beforehand and consequently a necessary spacing of the wall material layers and the transfer of air into the intermediate space between the inner layer and outer layer are made easier.

In a particularly preferred manner, the spacer elements are formed by edges of the ventilation openings in the inner layer. Ventilation openings, the edge of which is constructed to be displaced in the direction of the outer layer and transversely relative to the planar extent of the inner layer, can be constructed in the inner layer by punching or the like. If the inner layer and outer layer are in a tensioned state, the outer layer only has contact with these edge regions of the inner layer facing it. The operational reliability of the ventilation is increased by spacer elements which are constructed in this manner in that they produce the valve action of the ventilation in a particularly reliable manner. If there is a higher pressure in the sack inner space than in the environment, the outer layer can be lifted against only low resistance and the air can reach the environment from the sack inner space and through the ventilation channel. However, if the pressure in the sack inner space is lower than in the environment, the outer layer which adjoins the intermediate space is placed against the edge regions of the inner layer, wherein the pressing force of the layers against each other is increased by the reduced contact area thereof and prevents an inflow of air into the sack inner space.

In an advantageous embodiment of the invention, a covering sheet which covers the wall material edge portion is arranged at the at least one closure side. This cover sheet which is adhesively bonded in a planar manner also forms the ventilation channel. By fixing such a covering sheet to the closure side, the dimensional stability of this side is increased. In this case, the wall material edge portion can be arranged both at a wide edge of the closure side and between the two wide edges. If the wall material edge portion is arranged between the two wide edges, the ventilation channel is lengthened by a covering sheet placed thereon from the wall material edge portion as far as an edge of the closure side covering sheet contact face.

Preferably, a covering element which extends from the wall material edge portion as far as an edge of the covering sheet is arranged between the at least one closure side and the covering sheet. The closure side and the covering sheet are conventionally connected to each other by an adhesive which is applied to the entire contact face. The adhesive-free covering element allows the ventilation channel to be lengthened in that it partially prevents adhesive bonding of the wall material and the covering sheet by being placed on the adhesive between it and the wall material or between it and the covering sheet. It forms a non-bonded hollow space between the wall material edge portion and the edge of the covering sheet in such a manner that, in the event of a sufficient pressure difference between the intermediate space and the environment, ventilation is brought about by this hollow space and the remainder of the ventilation channel. Consequently, an air-permeable connection which adjoins the wall material edge portion is ensured between the covering sheet and the closure side. In this case, the use of the covering element allows the use of conventional methods for adhesively bonding the covering sheet and the closure side with the operational reliability of the ventilation being obtained. In turn, they reliably lead to stabilisation of the valve sack at the closure side.

Consequently, the ventilation channel does not have to be constructed continuously in this embodiment and in the other embodiments of the invention, which prevents the introduction of insects, moisture or other foreign bodies. Without adequate excess pressure, the upper side and lower side of the ventilation channel can be positioned one on the other.

[0026] Alternatively to the covering element, the closure side covering sheet contact face may have an adhesive recess face, on which the covering sheet and the closure side are not adhesively bonded in order to lengthen the ventilation channel.

Additional details and advantages of the invention can be taken from the schematically illustrated embodiments described below; in the drawings: Figure 1 is a perspective view of a portion of an embodiment of a valve sack according to the invention, Figure 2 is a perspective view of a closure side of an additional embodiment of a valve sack according to the invention, Figure 3 is a perspective view of a wall material blank for producing the embodiment of the valve sack according to the invention according to Figure 1.

The features of the embodiments according to the invention as explained below may also be the subject-matter of the invention individually or in combinations other than those set out or described, but always at least in combination with the features of claim 1. If advantageous, functionally equivalent components are indicated with identical reference numerals.

Figure 1 is a perspective view of a closure side 10, an auxiliary side 30 and a main side 28 of a ventable valve sack 2. The illustration of the valve sack 2 is sectioned in the lower region in this case. A wall material 4, from which the valve sack 2 is substantially constructed, comprises an outer layer 8 which is visible from outside and an inner layer 6 which internally adjoins and/or abuts the outer layer 8 and which is made visible in Figure 1 by a partial section of the main side 28.

Figure 3 is a perspective view of a non-closed valve sack blank. It comprises a tubular wall material 4. By closing the valve sack blank or the valve sack 2 formed therefrom, there is defined a sack inner space 12 which is indicated in Figure 3 as a result of the opened state of the valve sack blank. An intermediate space 14 is located between a portion of the inner layer 6 adjoining the sack inner space 12 and the outer layer 8. This intermediate space 14 is located in the illustrated embodiment according to Figure 1 at the main face between the inner layer 6 and the outer layer 8. In this case, the inner layer 6 is permeable to a gas and impermeable to a filling material which is intended to be poured into the sack inner space 12. This is achieved by a large number of ventilation openings 36 which are indicated by dots (cf.

Figure 1) and which are located in the inner layer 6 and which are illustrated in a partially enlarged state. The outer layer 8 which delimits the intermediate space 14 at the side facing the environment is impermeable both to a gas and to the filling material in this case. The intermediate space 14 can extend completely or partially over two main sides 28 and two auxiliary sides 30.

The ventable valve sack 2 has, at the closure side 10 illustrated in Figure 1, a mouth opening 34, in which a ventilation channel 18 opens. This ventilation channel 18 connects the intermediate space 14 and the environment so that air from the intermediate space 14 can reach the environment through the ventilation channel 18. In this case, the mouth opening 34 is located in a wall material edge portion 16, in which the inner layer 6 and the outer layer 8 of a wall material region are spaced apart from each other.

The closure side 10 of the ventable valve sack 2 is constructed by folding the wall material 4 to form a cross bottom. This cross bottom has an inner side fold, which is therefore visible on the real valve sack with respect to a smaller portion, and an outer side fold 20. The wall material edge portion 16, in which the mouth opening is located, is part of this outer side fold 20. Furthermore, the wall material edge portion adjoins the environment irrespective of a covering sheet or the like which can be applied to the closure side 10.

[0033] The ventilation channel 18 extends from the wall material edge portion 16 substantially in the direction of the longitudinal centre axis 22 thereof as far as a wide edge 26 of the closure side 10, at which the wall material 4 is folded and at which the outer side fold 20 adjoins a main side 28. The longitudinal centre axis 22 of the ventilation channel 18, which has at each location along the closure side 10 a substantially identical spacing with respect to the two transverse and parallel- extending ventilation channel transverse boundaries, extends parallel with the two narrow edges 24 of the closure side 10 (cf. Figure 1).

Figure 3 shows that the inner layer 6 and the outer layer 8 are connected to each other at the closure side along a wall material edge strip 32 which adjoins the wall material edge and which has a constant width along the periphery of the valve sack blank. This closure-side connection of the inner layer 6 and the outer layer 8 is interrupted in the portion of the wall material edge strip 32 which adjoins the wall material edge portion 16 in order to form the mouth opening 34, in which the inner layer 6 and outer layer 8 are spaced apart from each other.

Figure 2 shows a closure side 10 of a different embodiment of the valve sack according to the invention. A covering sheet 38, which is illustrated in a transparent manner and the edge side of which substantially corresponds to the narrow edges 24 and the wide edges 26 of the closure side 10, is positioned on the illustrated closure side 10. The covering sheet 38 is adhesively bonded to the closure side 10.

The outer side fold 20 does not extend from a wide edge 26 as far as the opposite edge, whereby the mouth opening 34 is located between the two wide edges 26 on the closure side 10. Since the applied covering sheet 38 is adhesively bonded to the closure side 10, the ventilation channel 18 from the mouth opening 34 as far as the closer wide edge 26 is formed by the covering sheet. In this region, the ventilation channel 18 further extends between the covering sheet 38 and the inner side fold outside the wall material 4. It is formed by a covering element 40 in the region which is marked with broken lines accordingly.

List of reference numerals: 2 Valve sack 4 Wall material 6 Inner layer 8 Outer layer Closure side 12 Sack inner space 14 Intermediate space 16 Wall material edge portion 18 Ventilation channel Outer side fold 22 Longitudinal centre axis 24 Narrow edge 26 Wide edge 28 Main side Auxiliary side 32 Wall material edge strip 34 Mouth opening 36 Ventilation opening 38 Covering sheet 40 Covering element

Claims (14)

Claims:

1. Ventable valve sack having a wall material (4) formed from a multi-layered plastic film, the wall material (4) having exactly two layers comprising one inner layer 5 (6) which is permeable to gas and non-permeable to a filling material and an outer layer (8) which is non-permeable to gas and having two closure sides (10), wherein a first closure side (10) is formed by closing the valve sack (2) and a second closure side (10) is arranged facing away from the first closure side (10), and wherein an intermediate space (14) is formed between a portion of the inner layer (6) which 10 delimits a sack inner space (12) and the outer layer (8), characterised in that at least one ventilation channel (18) which opens from a wall material edge portion (16) in such a manner that the intermediate space (14) is thereby configured to be ventable with respect to the environment is arranged at least at one closure side (10) of the valve sack (2) between the inner layer (6) and the outer 15 layer (8) of a wall material region and wherein the ventilation channel (18) is constructed in an outer side fold (20) which forms the first closure side (10).

2. Ventable valve sack according to Claim 1, characterised in that the at least one closure side (10) is configured by folding the wall material (4).

3. Ventable valve sack according to Claim 2, characterised in that the at least one closure side (10) is configured by folding the wall material (4) in the manner of a cross bottom.

4. Ventable valve sack according to Claim 1, characterised in that the outer side fold (20) has the wall material edge portion (16) which adjoins the environment.

5. Ventable valve sack according to any one of the preceding claims, 5 characterised in that a longitudinal centre axis (22) of the ventilation channel (18) extends substantially parallel with a narrow edge (24) of the at least one closure side (10).

6. Ventable valve sack according to any one of the preceding claims, 10 characterised in that the inner layer (6) and the outer layer (8) are connected to each other on the closure side (10) along a wall material edge strip (32) which adjoins the wall material edge, wherein a mouth opening (34) of the ventilation channel (18) is constructed only at the wall material edge portion (16) between the inner layer (6) and the outer layer (8).

7. Ventable valve sack according to any one of the preceding claims, characterised in that the inner layer (6) and the outer layer (8) are formed from the same material. 20

8. Ventable valve sack according to Claim 7, characterised in that the inner layer (6) and the outer layer (8) are formed primarily from a polyolefin.

9. Ventable valve sack according to claim 8, characterised in that the polyolefin is polyethylene.

10. Ventable valve sack according to any one of the preceding claims, characterised in that the portion of the inner layer (6) delimiting the sack inner space (12) has ventilation openings (36). 5

11. Ventable valve sack according to any one of the preceding claims, characterised in that the valve sack (2) has spacer elements which define the intermediate space (14).

12. Ventable valve sack according to Claim 10 and Claim 11, characterised in that 10 the spacer elements are formed by edges of the ventilation openings (36) in the inner layer (6).

13. Ventable valve sack according to any one of the preceding claims, characterised in that a covering sheet (38) which covers the wall material edge 15 portion (16) and which also forms the ventilation channel (18) is arranged at the at least one closure side (10).

14. Ventable valve sack according to Claim 13, characterised in that a covering element (40) which extends from the wall material edge portion (16) as far as an edge 20 of the covering sheet (38) is arranged between the at least one closure side (10) and the covering sheet 38).