Bag and method for producing the same
A sack is formed by first transverse sealing seams from a foil tube, and is provided with at least a first vent channel, which runs largely parallel to the axis of the film tube, and whose inner film layer has first vent openings for venting of the sack interior into the first vent channel. A second vent channel is provided, which is connected to the first vent channel by second vent openings, and which, in turn, has third vent openings, which vent the at least one second vent channel.
1. A sack produced from a film tube, comprising:
an inner film layer and an outer film layer,
at least a first vent channel and a second vent channel, the first and second vent channels being associated with a first, a second, and a third longitudinal sealing seam, the sack having a length in a direction of an axis (z) and a width in a direction of an axis (x), and the first and second vent channels extending substantially parallel to the axis (z) of the film tube,
the inner film layer having first vent openings therein for venting an interior of the sack into the first vent channel, the first vent openings being configured as holes in the inner film layer,
the first vent channel and the second vent channel being in communication via second vent openings for venting the first vent channel into the second vent channel, and
the outer film layer having third vent openings therein for venting the second vent channel to an exterior of the sack, the third vent openings being configured as holes in the outer film layer,
with the first vent openings and the third vent openings being located at substantially a same position relative to the length in the direction of the axis (z) of the sack,
with each of the second vent openings being configured as an interruption in the second longitudinal sealing seam, the interruption being located at a treated portion of the film tube that is bond-resistant to an adhesive, the treated portion being a section of the film tube having a coating thereon, and
with the first longitudinal sealing seam and the third longitudinal sealing seam each being without the interruptions over an entire longitudinal length of the seam.
2. The sack according to claim 1 , further comprising a third vent channel that extends substantially orthogonal to the first and second vent channels.
3. The sack according to claim 2 , wherein the third vent channel is provided on at least a first end of the sack, and wherein sealing of the sack at the first end thereof borders the third vent channel.
4. The sack according to claim 3 , further comprising another third vent channel provided on a second end of the sack.
5. The sack according to claim 4 , wherein the sack has at least one corner sealing, which, in the direction of the sack length axis (z), is positioned in front of the sack interior relative to the third vent channel.
6. The sack according to claim 1 , further comprising gussets, and wherein the third vent openings lie in the direction of the sack width axis (x) in an area of the gussets.
7. The sack according to claim 1 , wherein the exterior of the sack is the atmosphere.
8. The sack according to claim 1 , wherein the treated portion of the film tube that is bond-resistant is electrically resistant to bonding.
9. The sack according to claim 1 , wherein at least part of the first, second and third vent openings are equipped with filters.
10. The sack according to claim 1 , wherein the coating is a sprayed-on layer having a chemical that prevents bonding.
11. The sack according to claim 1 , wherein, in the direction of the sack length axis (z), at least one of the first vent openings, the second vent openings, and the third vent openings is spaced apart from others of the vent openings.
12. The sack according to claim 11 , wherein at least two of the first vent openings, the second vent openings, and the third vent openings are spaced apart from each other, such that one of the first vent openings, the second vent openings, and the third vent openings lies on a front of the sack, and another of the first vent openings, the second vent openings, and the third vent openings lies on another side of the sack.
13. A method of producing a sack according to claim 1 ,
comprising
unwinding a film tube from an unwinding device and feeding the film tube to a machine that separates the film tube by cross-seals to film tube pieces,
filling the sack formed during separation, and
closing the filled sack with an additional transverse seal.
14. The method of producing a sack according to claim 13 , wherein
a film tube that already has at least two vent channels arranged next to each other that are arranged largely parallel to the film tube axis is unwound by the unwinding device.
15. The method of producing a sack according to claim 13 , wherein
a film tube, having a first vent channel ( 20 ), is unwound by the unwinding device and fed to a machine that makes transverse seals before filling, through which at least a second vent channel is formed.
16. The method of producing a sack according to claim 13 , wherein
a film tube is unwound that already has at least two substantially parallel vent channels.