Flexible storage device comprising a flexible container and an inner liner

Patent metadata

Field	Value
Publication number	US-9938076-B2
Application number	US-201414908672-A
Country	US
Kind code	B2
Filing date	Jul 17, 2014
Priority date	Aug 2, 2013
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A storage device ( 1 ) for bulk material intended for powdery materials, includes a flexible container ( 2 ) for bulk material and an insulating inner liner ( 3 ), of which the surface resistivity is greater than 1.0×1012Ω, without a static electricity conductive layer and without a static electricity dissipation layer, the inner lining ( 3 ) covering the inner walls of the container, the inner lining ( 3 ) including micro-perforations that pass there through, distributed over the whole surface of the inner lining ( 3 ) in such a way that the breakdown voltage of the inner liner ( 3 ) is lower than 4 kV and the breakdown voltage of the wall of the container is lower than 6 kV.

First claim

The invention claimed is:

1. A bulk storage device ( 1 ) intended for powdery materials, said device comprising:
a flexible bulk container ( 2 ), the material of the container being an insulator, without antistatic additive or electrically conductive layer,
an insulating inner liner ( 3 ), of surface resistivity greater than 1.0×10 12 Ω, without a static electricity conducting layer and without a static electricity dissipation layer, said inner liner ( 3 ) covering the inner walls of the container, the thickness Δ of the inner liner ( 3 ) being greater than 60 microns and inferior or equal to 700 microns, said inner liner ( 3 ) comprising micro-perforations ( 4 ) that pass therethrough, the diameter of the micro-perforations ( 4 ) being between 5 microns and 130 microns, the micro-perforations being distributed over the whole surface of said inner liner ( 3 ), the density of the micro-perforations on the inner liner ( 3 ) being between 0.2 perforations per cm 2 and 2 perforations per cm 2 , and in such a way that the breakdown voltage of said inner liner ( 3 ) is lower than 4 kV and in that the breakdown voltage of the wall of the container is lower than 6 kV without requiring the device to be earthed,
such that the storage device can be qualified as a intermediate flexible bulk container classified as type B according to the standard 61340-4-4 Edition 2.0 2012-01.

2. The device as claimed in claim 1 , in which the inner liner ( 3 ) consists of a single film of material having said micro-perforations ( 4 ).

3. The device as claimed in claim 1 , in which the inner liner is a multilayer of several different insulators.

4. The device as claimed in claim 1 , in which the flexible bulk container ( 2 ) is formed from fabric ( 20 ).

5. The device as claimed in claim 4 , in which the fabric ( 20 ) is a coated fabric.

6. The device as claimed in claim 4 , in which the fabric ( 20 ) is a laminated fabric.

7. The device as claimed in claim 4 , in which the fabric ( 20 ) is a non-laminated and non-coated fabric.

8. The device as claimed in claim 4 , in which the fabric ( 20 ) of the flexible bulk container is a fabric permeable to air, preferably non-laminated and non-coated, so as to allow the de-aeration of the device ( 1 ) through the micro-perforations ( 4 ) of the inner liner ( 3 ) and through the fabric ( 20 ) of said container ( 2 ).

9. The device as claimed in claim 1 , in which the density of the micro-perforations ( 4 ) over the whole surface of the inner liner ( 3 ) is such that two neighboring micro-perforations are separated by a dimension δ less than or equal to 2 cm.

10. The device as claimed in claim 9 , in which the maximum surface area of the inner liner not having any micro-perforations must not exceed a disk of 2.5 cm in diameter.

11. The device as claimed in claim 1 , in which the diameter of the micro-perforations ( 4 ) is between 5 microns and 40 microns.

12. The device as claimed in claim 1 , in which the breakdown voltage of the container ( 2 )/inner liner ( 3 ) assembly is lower than or equal to 6 kV.

13. The device as claimed in claim 1 , in which the thickness Δ of the inner liner ( 3 ) is between 90 microns and 700 microns.

14. The device as claimed in claim 13 , in which the thickness Δ of the inner liner ( 3 ) is between 90 microns and 500 microns.

15. The device as claimed in claim 1 , in which the container forms a body comprising a bottom wall ( 21 ), four side walls ( 22 to 25 ) and a roof ( 26 ), said device comprising a flexible filling chute ( 27 ), fixed to the roof ( 26 ), extending from an opening of the roof, outside the body, and a flexible emptying chute ( 28 ), extending from an opening of the bottom wall ( 21 ), outside the body and in which the perforated inner liner ( 3 ) cover not only the inner walls of the body of the container, but also the inner wall of the filling chute ( 27 ) and the inner wall of the emptying chute ( 28 ).

16. The device as claimed in claim 15 , in which the perforated inner liner ( 3 ) covering not only the inner walls of the body of the container, the inner wall of the filling chute ( 27 ) and the inner wall of the emptying chute ( 28 ) consists of a gusset sheath, of a single piece, extending lengthwise, from the filling chute ( 27 ) to the emptying chute ( 28 ).

17. The device as claimed in claim 1 , in which the distribution of the micro-perforations ( 4 ) over the inner liner is uniform.

18. The device as claimed in claim 17 , in which the micro-perforations ( 4 ) are arranged in parallel lines, the micro-perforations of each line being separated by a constant distance between any two successive micro-perforations of the line, and in which the perforations of two successive lines are arranged staggered relative to one another.

19. The device as claimed in claim 1 , in which the material of the container ( 2 ) and/or the material of the inner liner ( 3 ) are chosen from polyethylene, polypropylene, polyamide, PET and a biopolymer.

20. A method for manufacturing a bulk storage device ( 1 ) for powdery materials, said device comprising:
a flexible bulk container ( 2 ), the material of the container being an insulator, without antistatic additive or electrically conductive layer, and
an insulating inner liner ( 3 ), of surface resistivity greater than 1.0×10 12 Ω, without a static electricity conducting layer and without a static electricity dissipation layer, said inner liner ( 3 ) covering the inner walls of the container, the thickness Δ of the inner liner ( 3 ) being greater than 60 microns and inferior or equal to 700 microns,

said method comprising a step of microperforating said inner liner ( 3 ) with micro-perforations ( 4 ) that pass therethrough, the diameter of the micro-perforations ( 4 ) being between 5 microns and 130 microns, the micro-perforations being distributed over the whole surface of said inner liner ( 3 ), the density of the micro-perforations on the inner liner ( 3 ) being between 0.2 perforations per cm 2 and 2 perforations per cm 2 , and in such a way that the breakdown voltage of said inner liner ( 3 ) is lower than 4 kV and in that the breakdown voltage of the wall of the container is lower than 6 kV without requiring the device to be earthed, such that the storage device can be qualified as an intermediate flexible bulk container classified as type B according to the standard 61340-4-4 Edition 2.0 2012-01.

21. The method for manufacturing a device as claimed in claim 20 , in which the micro-perforated inner liner is obtained from a non-perforated inner liner and by means of a perforation device comprising at least one roller provided, on its circumference, with needles, driven in rotation about its axis and rolling over the inner liner while perforating same.

22. The method as claimed in claim 21 , in which the perforation device comprises two contra-rotating rollers, each provided with needles on its circumference, driven in counter rotations, the two rollers rolling over the inner liner while perforation same.

23. The method as claimed in claim 21 , in which the micro-perforations are produced from a gusset sheath ( 6 ), directly in the gusset sheath, when the sheath is flat, in the form of a strip.

Assignees

• Roquette Freres
• So Bag

Inventors

• Lecocq Jean-Pierre
• Chevalier Nicolas

Classifications

• B31B2155/002

  by joining superimposed webs, e.g. with separate bottom webs · CPC title

• B26F1/24

  Perforating by needles or pins · CPC title

• B31B70/146

  using tools mounted on a drum · CPC title

• B65D88/54

  characterised by means facilitating filling or emptying · CPC title

• B65D88/1618

  double-walled or with linings · CPC title