U.S. patent application number 11/575871 was filed with the patent office on 2008-05-22 for flexible container for bulk material.
This patent application is currently assigned to NORDENIA DEUTSCHLAND EMSDETTEN GMBH. Invention is credited to Siegfried Hartmann, Erich Jordan.
Application Number | 20080118187 11/575871 |
Document ID | / |
Family ID | 34982108 |
Filed Date | 2008-05-22 |
United States Patent
Application |
20080118187 |
Kind Code |
A1 |
Jordan; Erich ; et
al. |
May 22, 2008 |
Flexible Container for Bulk Material
Abstract
A flexible bulk material container has a container body having
at least one opening for filling and emptying the bulk material
container. Carrying loops are attached to the container body. The
container body and the carrying loops are made from an electrically
non-conductive base fabric. A first conductive element for
conducting an electrostatic charge of the bulk material container
is provided which electrostatic charge occurs primarily during
filling or emptying of the bulk material container. At least one
the carrying loops has a discharge device. The first conductive
element is connected to the discharge device and is a coating of
the container body. At least one of the coating and the discharge
device is made from a thermoplastic synthetic material containing a
conductivity-increasing additive and having a surface resistance of
between 10.sup.8 Ohm and 10.sup.11 Ohm.
Inventors: |
Jordan; Erich; (Horstel,
DE) ; Hartmann; Siegfried; (Ibbenburen, DE) |
Correspondence
Address: |
GUDRUN E. HUCKETT DRAUDT
SCHUBERTSTR. 15A
WUPPERTAL
42289
omitted
|
Assignee: |
NORDENIA DEUTSCHLAND EMSDETTEN
GMBH
Emsdetten
DE
|
Family ID: |
34982108 |
Appl. No.: |
11/575871 |
Filed: |
July 9, 2005 |
PCT Filed: |
July 9, 2005 |
PCT NO: |
PCT/EP05/07460 |
371 Date: |
January 4, 2008 |
Current U.S.
Class: |
383/16 |
Current CPC
Class: |
D03D 15/533 20210101;
B65D 88/165 20130101 |
Class at
Publication: |
383/16 |
International
Class: |
B65D 90/46 20060101
B65D090/46; B65D 88/16 20060101 B65D088/16; B65D 33/14 20060101
B65D033/14; B65D 30/04 20060101 B65D030/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 23, 2004 |
DE |
10 2004 046 579.7 |
Claims
1-12. (canceled)
13. A flexible bulk material container comprising: a container body
having at least one opening for filling and emptying the bulk
material container; carrying loops attached to the container body;
wherein the container body and the carrying loops are comprised of
an electrically non-conductive base fabric; a first conductive
element for conducting an electrostatic charge of the bulk material
container which electrostatic charge occurs primarily during
filling or emptying of the bulk material container; at least one
the carrying loops having discharge means correlated therewith;
wherein the first conductive element is connected to the discharge
means; wherein the first conductive element is a coating of the
container body; wherein at least one of the coating and the
discharge means is comprised of a thermoplastic synthetic material
containing a conductivity-increasing additive and having a surface
resistance of between 10.sup.8 Ohm and 10.sup.11 Ohm.
14. The bulk material container according to claim 13, comprising
second conductive elements correlated with the carrying loops or
partial areas of the container body, respectively, wherein the
second conductive elements are comprised of a thermoplastic
synthetic material containing a conductivity-increasing additive
and having a surface resistance of between 10.sup.8 and 10.sup.11
Ohm, wherein the second conductive elements are ribbons or
threads.
15. The bulk material container according to claim 14, wherein the
discharge means is arranged within said at least one carrying loop,
wherein the second conductive elements are arranged approximately
parallel to a longitudinal extension of the carrying loops in an
area having a width transversely to the longitudinal extension of
the carrying loops that is maximally two and a half times a width
of the carrying loops, respectively.
16. The bulk material container according to 14, wherein the second
conductive elements are incorporated in a warp direction in the
base fabric.
17. The bulk material container according to 14, wherein the
coating is arranged on a side of the container body opposite a side
to which the carrying loops are attached, wherein the second
conductive elements correlated with the partial areas of the
container body connect the coating with the second conductive
elements correlated with the carrying loops and/or the discharge
means.
18. The bulk material container according to 13, wherein the
discharge means is a thread having thread loops.
19. The bilk material container according to claim 18, wherein the
thread loops are provided on edges of the at least one carrying
loop.
20. The bulk material container according to claim 13, wherein the
discharge means has a plurality of strips made form a conductive
material and projecting at least partially from the base
fabric.
21. The bulk material container according to claim 20, wherein the
strips are conductively connected with one another.
22. The bulk material container according to claim 20, wherein the
strips are part of a polymer film.
23. The bulk material container according to claim 20, wherein the
discharge means has a seam reinforcement.
24. The bulk material container according to claim 13, wherein the
discharge means is incorporated in the weft direction into the base
fabric of said at least one carrying loop.
25. The bulk material container according to claim 14, wherein at
least two of the carrying loops comprise the discharge means,
wherein the second conductive elements of said at least two
carrying loops are conductively connected to one another.
Description
[0001] The invention relates to a flexible container for bulk
material comprising a container body that can be filled with bulk
material and emptied again through at least one opening, wherein
the container body can be lifted by means of carrying loops that
are attached to the container body. The container body comprises an
electrically non-conductive base fabric as well as a conductive
element that is suitable for conducting an electrostatic charge of
the bulk material container occurring preferably during filling or
emptying, wherein the conductive element, for discharging the bulk
material container, is connected to at least one discharge means
correlated with a carrying loop.
[0002] DE 299 24 464 discloses a bulk material container of the
aforementioned kind that is suitable for corona-discharge. Such a
bulk material container has in the area of its carrying loops at
least one discharge means correlated with a carrying loop wherein
the discharge means projects from the material of the carrying loop
in the form of an exposed conductor. Despite the fact that corona
discharges are possible anytime, partial areas of the container
body can become temporarily charged and this leads to the hazard of
arc-over. On the one hand, this is so because the corona discharge
occurs at a comparative low rate in a secured area in the vicinity
of the support frame, and, on the other hand, because the electric
conductors woven into the fabric can still conduct charges well as
a result of their comparatively minimal electrical surface
resistance.
[0003] It is therefore an object of the present invention to
improve the article according to the preamble of claim 1 with
regard to its electrostatic properties.
[0004] The object is solved by an article of the aforementioned
kind in which the conductive element that is formed as a coating of
the container body and/or the discharge means are/is comprised of a
thermoplastic synthetic material wherein, as a result of a
conductivity-increasing additive, it has a surface resistance
between 10.sup.8 and 10.sup.11 Ohm. The bulk material container
according to the invention thus has a coating, preferably applied
to the inner side of the container body, that takes over the tasks
of the prior art conductive paths woven into the fabric material
and arranged usually in a grid pattern. Because the resistance of
the coating surface is between 10.sup.8 Ohm and 10.sup.11 Ohm,
i.e., within a range that is above 10.sup.8 Ohm of an electrical
conductor conventionally used in connection with bulk material
containers, there is still charge transport in the direction of the
discharge means correlated with the carrying loops but it is not
capable of enabling arc-over in case of local charging because of
the high resistance.
[0005] The container according to the invention thus has for
dissipating its electrostatic charges only the antistatic coating
as well as the discharge means correlated with at least one
carrying loop. A mandatory requirement for the functioning of the
bulk material container is that the coating is in contact with the
discharge means. Depending on the configuration of the bulk
material container, for example, with a container body having a
rectangular or round cross-section, it must also be ensured that
the coating of the individual walls of the container body are in
contact with one another. This contact can be realized, for
example, by applying the coating after individual walls have been
sewn together.
[0006] It was found that for a surface resistance of the coating
and/or of the discharge means between 10.sup.9 Ohm and 10.sup.10
Ohm, measured e.g. in accordance with DIN 53482, the bulk material
container according to the invention functions particularly
well.
[0007] Advantageously, the bulk material container according to the
invention can have additional conductive elements, correlated
respectively with the container body or the carrying loop and
configured as ribbons or threads and also comprised of a
thermoplastic synthetic material that, as a result of an additive
that increases its conductivity, has a surface resistance between
10.sup.8 Ohm and 10.sup.11 Ohm. These additional conductive
elements are to be provided, inasmuch as they are arranged in the
area of the carrying loop fabric and extend in this area preferably
in warp in the direction of longitudinal extension of the carrying
loop, to connect the discharge means to the conductive means of the
container body and to ensure a continuous charge transport.
[0008] The additional conductive elements are arranged moreover
preferably in areas of the container body that are exposed to
particularly high mechanical loads and enable thus also an
excellent dissipation of the collected electrostatic charge in the
direction of the discharge means and discharge thereat of the bulk
material container by means of corona discharge, even in case of a
coating that has been possibly damaged after extended use.
[0009] It is within the boundaries of the invention to provide
grounding of the bulk material container that provides an
additional safety means of the container in addition to the at
least one discharge means arranged in the area of at least one
carrying loop.
[0010] According to a further embodiment of the invention, the
discharge means is configured as a thin thread and has thread loops
preferably in the area of the edges of the carrying loops which
thread loops project past the edges of the carrying loop or project
from the material of the carrying loop. The thread is very thin in
order to also enable a corona discharge and is incorporated in the
weft direction into the base fabric of the carrying loop. Such a
thread is advantageously in conductive contact with the surface of
the container body by means of additional conductive elements that
are incorporated in the warp direction as well as by means of the
coating according to the invention and therefore contributes
decisively to the discharge of the container body.
[0011] According to another advantageous embodiment of the
invention, at least two carrying loops have discharge means wherein
the carrying loops are in conductive contact with one another, for
example, by means of conductive elements. These conductive elements
that extend preferably in the corner areas of the container body
assist in the uniform discharge of the bulk material container.
[0012] Further advantages and details of the invention result from
the schematic illustrations of an article according to the
invention described in the following. The illustrations show
in:
[0013] FIG. 1 a perspective view of a bulk material container
according to the invention;
[0014] FIG. 2 a plan view onto the area of a carrying loop with
discharge means and additional conductive elements;
[0015] FIG. 3 a plan view onto a part of a discharge means.
[0016] The bulk material container according to the invention
comprises a container body 1 that can be filled by means of filling
socket 3 arranged at the topside 2 through an opening 4 (FIG. 1).
Ties 5 serve for closing the filling socket 3. On the bottom side 6
of the container body 1 there is also an opening 7 through which
the bulk material can be emptied from the container body through an
outlet socket 8 that can also be closed by ties 5.
[0017] In the corner areas of the topside 2 carrying loops 11 are
sewn to the sidewalls 9 of the container body 1. All carrying loops
11 comprise parts of a discharge means 14 illustrated by thin lines
12.
[0018] Moreover, the bulk material container according to the
invention has in accordance with the invention additional
conductive elements 13 that are arranged approximately parallel to
the longitudinal extension of the carrying loops 11, attached to
the container body 1 and comprising the discharge means 14, in an
area whose width transverse to the longitudinal extension of the
carrying loop 11 is maximally two and half times, preferably
maximally two times, the width of the carrying loop 11. In this
way, the particularly kink-prone corner areas of the bulk material
container, in addition to being provided with a coating, are also
provided with conductive elements that ensure in the case of the
coating of the buck material container being damaged, in particular
at the greatly loaded areas, an unimpeded dissipation of the charge
that is being collected on the bulk material container.
[0019] The additional conductive elements 13, of which some can be
arranged in the carrying loops as will be explained in more detail
in the following, are preferably incorporated in the warp direction
of the base fabric. The expenditure that has been required up to
now for incorporating the conductive elements, usually employed in
the prior art by frequently being incorporated in a grid
arrangement in the base fabric, is reduced significantly in the
bulk material container according to the invention.
[0020] In a further advantageous embodiment of the invention, the
carrying loops 11 are provided on a different side of the container
body 1 than the coating, for example, on its outer side. The
additional conductive elements 13, woven in the longitudinal
direction of the carrying loops into the base fabric of the
container body 1, connect by means of their arrangement the coating
and the conductive elements of a carrying loop 11 with one another
without both of them having to be arranged on the same side of the
container body. This is advantageous for the surface of the inner
side of the container body 1.
[0021] In FIG. 2 a detail of the carrying loop 11 is shown; in
addition to the conductive elements 13 incorporated in the warp
direction, the carrying loop has discharge means 14 incorporated
primarily in the weft direction and provided with a plurality of
strips 16 that are projecting at least partially from the base
fabric and are made of a conductive material, preferably a polymer
film. In addition, the discharge means 14 projects in the area of
edges 17 of the carrying loop 11 into the surroundings, preferably
in the form of a loop, in order to assist particularly well corona
discharge thereat. The distances between the individual additional
conductive elements 13 that are used in the form of
electrostatically discharging yarns or ribbons are between 3 and 20
mm for the conductive elements 13 correlated with the carrying
loops 11 as well as for the conductive elements 13 correlated with
the container body 1. It is understood that the additional
conductive elements 13 of the container body 1 and carrying loop 11
are in contact with one another.
[0022] It is also advantageous when the individual strips 16 of the
discharge means 14 are connected conductively with one another in
order to enhance the uniform corona discharge.
[0023] Advantageously, the discharge means 14 is embodied as a
polymer film strip from which the individual strips 16 are cut out
(FIG. 3). Since a corona discharge preferably takes place at the
narrow edge areas of the discharge means, as a result of the great
edge area the polymer film is suitable for corona discharge across
large areas. Instead of strips that are arranged perpendicularly to
the longitudinal extension of the film, other cutting patterns or
strip patterns are conceivable, in particular those that have long
edge areas in comparison to their surface area.
[0024] For reinforcing the polymer film, a reinforcement seam 18 is
applied to the film wherein for this purpose threads of synthetic
material, metal or other materials can be used. The
electrostatically conductive polymer film strips of the discharge
means 14 as well as the fine yarn loops of the discharge means
provided as an alternative or as a supplement and having, for
example, a thickness of Dtex 1100/100, are incorporated in the
transverse direction and are in contact with the additional
conductive elements 13 that are woven in the longitudinal direction
(warp) and embodied as electrostatically discharging ribbons or
yarns. The carrying loops 11 produced in this way are then
contacted with the conductive element embodied as a coating and the
additional conductive elements 13 that are arranged on the
sidewalls 9 of the container body 1. It is also conceivable that,
instead of the coating, conventional conductive elements arranged
in a grid pattern are used that discharge the bulk material
container according to the invention in cooperation with the
polymer film comprising the discharge strips 16.
[0025] The antistatic coating embodied as the conductive element
can be comprised of a plurality of thermoplastic synthetic
materials that comprise additives that increase their conductivity.
The latter can be, for example, a polymer that is penetrated by an
electrically conductive network of microcrystalline needles that,
depending on the quantity that is being embedded, can vary the
discharge properties of the surface in the disclosed range. It was
found that such an additive increasing the conductivity can be
admixed in a quantity of 5 percent to 25 percent by weight into the
synthetic material, comprised preferably of polyolefin, in order to
bring the resistance into the disclosed range.
* * * * *