U.S. patent application number 11/935244 was filed with the patent office on 2008-06-19 for plastic bag with improved air evacuation structure.
This patent application is currently assigned to MARKO I.R.D.C.. Invention is credited to Ludovic CAPT, Mark FROHLICH, Gonzalo GONZALES, Roger TAMBAY.
Application Number | 20080144979 11/935244 |
Document ID | / |
Family ID | 39047950 |
Filed Date | 2008-06-19 |
United States Patent
Application |
20080144979 |
Kind Code |
A1 |
CAPT; Ludovic ; et
al. |
June 19, 2008 |
PLASTIC BAG WITH IMPROVED AIR EVACUATION STRUCTURE
Abstract
A plastic bag comprising a first face and a second face, at
least a portion of each being 2-ply and having an intermediate
space therebetween, the 2-ply portion of the first face having an
inner layer of air-impervious plastic material having openings
therein; the 2-ply portion of the second face having an outer layer
of air-impervious plastic material, the outer layer having openings
therein permitting air to pass therethrough, the openings of the
outer layer having a smaller average opening area than an average
opening area of the openings of the inner layer of the first face;
and a filtering chamber formed between the inner layer and the
outer layer such that air in an interior of the bag may egress the
bag by passing through the filtering chamber, the air being at
least partially filtered of particulate matter as it egresses the
bag.
Inventors: |
CAPT; Ludovic; (Montreal,
CA) ; FROHLICH; Mark; (St. Leonard, CA) ;
GONZALES; Gonzalo; (Montreal, CA) ; TAMBAY;
Roger; (Rosemere, CA) |
Correspondence
Address: |
OSLER, HOSKIN & HARCOURT, LLP (OTHER)
1000 DE LA GAUCHETIERE STREET WEST, SUITE 2100
MONTREAL
QC
H3B-4W5
omitted
|
Assignee: |
MARKO I.R.D.C.
St. Leonard
CA
|
Family ID: |
39047950 |
Appl. No.: |
11/935244 |
Filed: |
November 5, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60864589 |
Nov 6, 2006 |
|
|
|
60954145 |
Aug 6, 2007 |
|
|
|
Current U.S.
Class: |
383/207 ;
383/100; 383/109 |
Current CPC
Class: |
B65D 31/04 20130101;
B65D 33/01 20130101; B65D 31/145 20130101; B65D 31/10 20130101 |
Class at
Publication: |
383/207 ;
383/109; 383/100 |
International
Class: |
B65D 33/00 20060101
B65D033/00; B65D 30/10 20060101 B65D030/10; B65D 33/01 20060101
B65D033/01 |
Claims
1. A plastic bag comprising: a first face, at least a portion
thereof being 2-ply and having a first intermediate space
therebetween, the 2-ply portion of the first face having an inner
layer of air-impervious plastic material having openings therein
permitting air to pass therethrough; a second face, at least a
portion thereof being 2-ply and having a second intermediate space
therebetween, the 2-ply portion of the second face having an outer
layer of air-impervious plastic material, the outer layer having
openings therein permitting air to pass therethrough, the openings
of the outer layer having a smaller average opening area than an
average opening area of the openings of the inner layer of the
first face, the first intermediate space and the second
intermediate space being fluidly interconnected; whereby a first
filtering chamber is formed between the inner layer and the outer
layer such that air in an interior of the bag may egress the bag by
passing through the openings of the inner layer and through the
openings of the outer layer, the air being at least partially
filtered of particulate matter as it egresses the bag.
2. The plastic bag of claim 1, wherein the bag is a 2-ply bag.
3. The plastic bag of claim 2, wherein the first face and the
second face are different faces of the bag.
4. The plastic bag of claim 3, wherein no other layer of any other
face of the bag has openings therein permitting air to pass
therethrough.
5. The plastic bag of claim 2, wherein the first face and the
second face are the same face of the bag.
6. The plastic bag of claim 5, wherein the first intermediate space
and the second intermediate space are the same intermediate
space.
7. The plastic bag of claim 6, wherein the openings of the outer
layer of the second face are offset from the openings of the inner
layer of the first face.
8. The plastic bag of claim 6, wherein in the absence of air and
particulate matter in the filtering chamber, the outer layer of the
second face and the inner layer of the first face lie flat against
one another.
9. The plastic bag of claim 6, further comprising: a third face, at
least a portion thereof being 2-ply and having a third intermediate
space therebetween, the 2-ply portion of the third face having an
inner layer of air-impervious plastic material having openings
therein permitting air to pass therethrough; a fourth face, at
least a portion thereof being 2-ply and having a fourth
intermediate space therebetween, the 2-ply portion of the fourth
face having an outer layer of air-impervious plastic material, the
outer layer having openings therein permitting air to pass
therethrough, the openings of the outer layer having a smaller
average opening area than an average opening area of the openings
of the inner layer of the third face, the third intermediate space
and the fourth intermediate space being fluidly interconnected;
whereby a second filtering chamber is formed between the inner
layer and the outer layer such that air in an interior of the bag
may egress the bag by passing through the openings of the inner
layer and through the openings of the outer layer, the air being at
least partially filtered of particulate matter as it egresses the
bag.
10. The plastic bag of claim 9, wherein the first intermediate
space, the second intermediate space, the third intermediate space,
and the fourth intermediate space are all fluidly interconnected
forming such that the first filtering chamber and the second
filtering chamber are the same filtering chamber.
11. The plastic bag of claim 10, wherein the third face and the
fourth face are the same face of the bag.
12. The plastic bag of claim 11, wherein the third intermediate
space and the fourth intermediate space are the same intermediate
space.
13. The plastic bag of claim 12, wherein the openings of the outer
layer of the fourth face are offset from the openings of the inner
layer of the third face.
14. The plastic bag of claim 11, wherein in the absence of air and
particulate matter in the filtering chamber, the outer layer of the
fourth face and the inner layer of the third face lie flat against
one another.
15. The plastic bag of claim 12, wherein the first face and the
second face are a front face of the bag, and the third face and the
fourth face are a rear face of the bag.
16. The plastic bag of claim 15, wherein only the front face and
the rear face of the bag have a layer having openings therein.
17. The plastic bag of claim 15, wherein the openings in the outer
layer of the second face and the openings in the outer layer of the
fourth face are arranged with respect to each other such that the
outer layer of the bag may be ripped apart along a tear line
including such openings.
18. The plastic bag of claim 1, wherein the inner-layer openings
have a jagged edge.
19. The plastic bag of claim 18, wherein the outer-layer openings
have a non-jagged edge.
20. The plastic bag of claim 1, wherein a total opening area of the
openings of the inner layer is greater than a total opening area of
the openings of the outer layer.
21. A plastic bag comprising: an inner layer of air-impervious
plastic material, at least a portion of which has openings therein
permitting air to pass therethrough; an intermediate layer of
air-impervious plastic material, at least a portion of which has
openings therein permitting air to pass therethrough; and an outer
layer of air-impervious plastic material, at least a portion of
which has openings therein permitting air to pass therethrough.
22. The plastic bag of claim 21, wherein: the openings of the outer
layer have an average opening area that is smaller than an average
opening area of the openings of the intermediate layer; and the
average opening area of the openings of the intermediate layer is
smaller than an average opening area of the openings of the inner
layer whereby a filtering chamber is formed such that air in an
interior of the bag may egress the bag by passing through the
openings of the inner layer, through the openings of the
intermediate layer, and through the openings of the outer layer,
the air being at least partially filtered of particulate matter as
it egresses the bag.
23. The plastic bag of claim 22, wherein the openings of the outer
layer are offset from the openings of the intermediate layer; and
the openings of the intermediate layer are offset from the openings
of the inner layer.
24. The plastic bag of claim 22, wherein in the absence of air and
particulate matter in the filtering chamber, the outer layer, the
intermediate layer and the inner layer lie flat against one
another.
25. The plastic bag of claim 22, wherein the bag has a plurality of
faces including a front face and a rear face, and the openings are
located solely on the front face and the rear face of the bag.
26. The plastic bag of claim 22, wherein the inner-layer openings
have a jagged edge.
27. The plastic bag of claim 26, wherein the outer-layer openings
have a non-jagged edge.
28. A plastic bag comprising: a front face; a rear face; at least a
portion of the front and rear face being 2-ply and having a first
intermediate space therebetween; the 2-ply portion of the front and
rear face each having an inner layer of air-impervious plastic
material, the inner layers having openings therein permitting air
to pass therethrough; the 2-ply portion of the front and rear face
each having an outer layer of air-impervious plastic material, each
of the outer layers having openings permitting air to pass
therethrough, the openings of the outer layers arranged with
respect to each other such that the outer layer made be removed
from the bag by being ripped along a tear including the openings of
the outer layer.
29. The plastic bag of claim 28, wherein the openings of the outer
layer are serrations at least a length of the bag.
30. The plastic bag of claim 29, wherein the bag is one selected
from a group consisting of open-mouth bags and valve bags.
31. The plastic bag of claim 29, wherein: the openings of the outer
layer have an average opening area that is smaller than an average
opening area of the openings of the inner layer; whereby a
filtering chamber is formed such that air in an interior of the bag
may egress the bag by passing through the openings of the inner
layer and through the openings of the outer layer, the air being at
least partially filtered of particulate matter as it egresses the
bag.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present invention claims priority to U.S. Provisional
Patent Application Nos. 60/864,589 filed Nov. 6, 2006 and
60/954,145 filed Aug. 6, 2007, both entitled "Plastic Bag with
Improved Air Evacuation Structure". The entirety of each of these
documents is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to plastic bags such as those
that may be used for packaging bulk products.
BACKGROUND OF THE INVENTION
[0003] Bulk products, such as concrete, plaster, foodstuffs, pet
foods and litters, lawn care products, salt, and many others, are
conventionally transported, distributed, and sold in bags.
Depending on the application, these bags are typically made of
paper or plastic, both of which have their advantages and
drawbacks, which may either be inherent and/or dependent on the
particular product being packaged.
[0004] Most bags used with cement and concrete products and other
heavy flowable contents are large multi-wall paper bags with fill
valves, like those commonly seen palletized in home improvement
centers throughout the U.S. They typically contain products, such
as 60# mortar and concrete mix and 94# cement and concrete mix,
sold to consumers for use in home, garden and yard applications.
The chief reason paper valve bags are used for these applications
is primarily due to per unit costs and productivity factors. Paper
valve bags cost more than standard, top-loading plastic bags, but
the paper bags are much faster to fill, thus substantially
improving productivity and output.
[0005] Nonetheless, as anyone experienced in the art knows, there
are several problems associated with conventional paper bags. In
addition to the high cost, other disadvantages of paper packaging
include the consumption of five times the storage space of plastic,
the vulnerability of cement and concrete products stored in paper
to weather conditions (especially rain and moisture), and the
vulnerability of paper to pest infestations. Another significant
disadvantage of paper packaging is that it often rips or breaks,
spilling out its contents. Indeed, this occurs so often that in
some home improvement centers, an employee is assigned the
full-time task of cleaning up bulk materials spilled from ripped or
broken paper bags. Both the wasted material and the time spent
cleaning it up are a significant wasted expense.
[0006] To improve this situation, one prior art solution was to use
a plastic bag for packaging such materials. International Patent
Publication No. WO 03/000005 entitled "Flowing Bag Filling System
and Bag Therefor" published on Jan. 3, 2003 (herein incorporated by
reference in its entirety) describes a bag particularly adapted for
this purpose. It provides a bag having an inwardly disposed seam
manufactured from a sheet of plastic bag material having two major
surfaces and two parallel side edges. A first seam seals the two
parallel side edges together at the same major surface with the
side edges disposed inwardly of the tube to form the sheet of
plastic bag material into a tube with internal flap portions
extending interiorly of the tube. At least one seal across the tube
is provided for forming at least a three-sided bag structure (and
preferably two seals across the tube for forming a closed
four-sided bag structure) whereby pressure in the interior of the
bag acts against the internal flap portions disposed inwardly of
the tube to enhance the sealing of the seam. The bag is filled at
an opening defined along the opposite side edges of the seam facing
inwardly of the tube.
[0007] The bag of the '005 publication was an improvement over the
then conventional paper bags. Being made of plastic, it was
lightweight, took up less storage space, and was significantly less
prone to ripping or breaking. Moreover, these bags were not subject
pest infestation. They were impervious to fluids, meaning that rain
water could not cause the bags to deteriorate; nor could unwanted
moisture pass through the bags and into the contents thereof (it
being particularly important to keep contents such as cement or
concrete moisture-free).
[0008] However, fluid-imperviousness, while clearly helpful in some
ways, is a major problem in others, particularly in the filling of
the bag with its contents. In order to fill the bag with its
contents, the bulk material to be put into the bag (such as cement
or concrete) must be fluidized by being mixed with and suspended in
moving air to form a flowing stream of material/air mixture. The
more fine the particles of the material, the more air that is
required to fluidize them and create the flowing material/air
stream. Fine materials in powder form require a significant amount
of air to be fluidized and moved.
[0009] Once the flowing fluidized mixture is created it is directed
into the bag, wherein the material is deposited and the air must be
withdrawn. Given the plastic material of the bag, the plastic
material being impervious to fluids, some means for removing the
air must be provided. The means described in the '005 publication
(at paragraph 54 and in FIG. 15) is an air evacuation system
combined with the filling system to withdraw air from the bag
during filling operations. While adequate for its intended purpose,
that system is not optimal. The difficultly is that its does not
completely "defluidize" the air/material mixture, and leaves some
air entrapped in the bag. This makes these bags unwieldy and
difficult (and in some instances very difficult or nearly
impossible) to stack. This situation is undesirable for bags that
are destined to be palletized for transportation and/or
distribution, as stackablity of the bags is extremely desirable.
Simple and economical means for allowing air entrapped in the bag
after the bag has been filled would be desirable.
[0010] One such means for allowing air to escape from a plastic bag
is described in European Patent No. 0,444,261, entitled "Flexibles
Verpackungsbehaltnis in Form eines Sackesoder Beutels aus
Kunststoffolle" ("Flexible Packaging Container in the Form of a Bag
or Pouch, Made from Plastic Film") published on Aug. 11, 1993
(herein incorporated by reference in its entirety). The '261 patent
provides a flexible packaging container in the form of a bag or
pouch made from plastic film or similar material which is
impermeable to air, which has in the bag wall an air outlet region
in which the bag material as an outside wall part is provided with
perforations for passage of air from the filling space of the bag.
The perforated bag material is covered on the inside by an
air-permeable inside wall part. The inside wall part consists, in
turn, of material, such as plastic film, which is impermeable to
air and, for its air-permeable construction, is likewise provided
with perforations which, however, although being the same size,
have a construction and arrangement for a greater air passage than
the perforations of the outside wall part in the air outlet region
of the bag wall, the inside wall part and the outside wall part
jointly bounding an air chamber which is closed all round at the
edge. The difficulty with the bag described in the '261 patent is
that, while air is indeed permitted to escape from the interior, so
is the material that the bag is supposed to contain unless some
kind of external filter is added. This escape of material is
undesirable where the material is a fine power such as cement or
plaster; and external filters are expensive and needlessly
complicate the manufacture process.
[0011] There is thus a need in the art for a fluid-impervious bag
made from a plastic material having structure allowing for air
entrapped in the interior of the bag to escape therefrom, while at
the same time preventing an undesirable quantity of material
contained within the bag from escaping.
STATEMENT OF THE INVENTION
[0012] It is therefore an object of the present invention to
provide a plastic bag with an improved air evacuation structure
over plastic bags of the prior art.
[0013] Thus, in one aspect, as embodied and broadly described
herein, the present invention provides a plastic bag comprising a
first face, at least a portion thereof being 2-ply and having a
first intermediate space therebetween, the 2-ply portion of the
first face having an inner layer of air-impervious plastic material
having openings therein permitting air to pass therethrough; a
second face, at least a portion thereof being 2-ply and having a
second intermediate space therebetween, the 2-ply portion of the
second face having an outer layer of air-impervious plastic
material, the outer layer having openings therein permitting air to
pass therethrough, the openings of the outer layer having a smaller
average opening area than an average opening area of the openings
of the inner layer of the first face, the first intermediate space
and the second intermediate space being fluidly interconnected;
whereby a first filtering chamber is formed between the inner layer
and the outer layer such that air in an interior of the bag may
egress the bag by passing through the openings of the inner layer
and through the openings of the outer layer, the air being at least
partially filtered of particulate matter as it egresses the
bag.
[0014] Although many different bag constructions are contemplated
(some of which are described hereinbelow), it is preferred for most
embodiments of the present invention that the bag simply be of a
two-layer construction (i.e. 2-ply) in order to simplify
manufacturing and to avoid increasing costs. In bags of a two-layer
construction there will be an inner layer (i.e. the layer to be in
contact with the contents of the bag), an outer layer (i.e. the
layer surrounding the inner layer and in contact with the
environment), and an intermediate space therebetween. The term
"intermediate space" should be understood as encompassing the
situation where the inner layer and the outer layer are in direct
contact, and thus there is no actual space between them (i.e. bags
of the present invention should be understood to have an
intermediate space even if situations exist during the course of
their use during which there is no actual space between the
relevant layers).
[0015] Typically bags of the present invention (when filled with
material) will be three-dimensional rectilinear bodies, most
commonly rectangular parallelepipeds. As would be apparent to those
of ordinary skill in the art, in such cases the bags will have 6
faces: a front face, a rear face, a left side face, a right side
face, a bottom face and a top face. The front face and the rear
face will typically be the two parallel rectangular faces with the
greatest surface area, and the remainder of the faces will be
defined to be consistent with the front face and the rear face. In
cases where the bags are cubes, the same 6 faces will be present,
however, any two parallel faces may be the front face and the rear
face, with the remainder of the faces being consistently defined
therewith. Where the bag is a three-dimensional curvilinear body,
for example, a right circular cylinder, the front face and the rear
face may be opposing portions of an appropriate exterior
surface.
[0016] For greater certainty it should be understood that a "face"
of a bag of the present invention includes all of the layers
comprising the face and not just the outer layer. Thus for example
for 2-ply bags the front face includes both the front face outer
layer and the front face inner layer. The front face inner layer is
termed "front face" even though it actually faces the front face
outer layer.
[0017] An "opening" in a layer of material should be understood to
mean an absence of material, however caused or formed, that allows
air to pass through the layer. For example openings may be formed
by needle perforation (the preferred method for forming the
openings in the outer layer) or by a slicing with spinning blade
(the preferred method for forming the openings in the inner layer).
The average opening area of the openings of a face is calculated by
determining the effective cross-sectional open area of each of the
openings of a face, and averaging them.
[0018] Bags of the present invention provide a filtering chamber
between the inner layer of the first face and the outer layer of
the second face such that air in an interior of the bag may egress
the bag by passing through the openings of the inner layer into the
filtering chamber and then through the openings of the outer layer,
such that the air is at least partially filtered of particulate
matter as it egresses the bag. Preferably, what occurs is that the
inner and outer layers act as a progressive sieve. Thus, the inner
layer will allow air to escape but will filter out all particles
over a certain size allowing only (generally) very fine particles
to pass therethrough entrained with the air. The openings in the
outer layer are however smaller and will again allow to air to pass
therethrough while filtering out particles over a certain size even
smaller than that of the inner layer. Ideally, if possible, the
size of the outer layer is such that no particles will be allowed
to pass therethrough, only air. If not possible, the size is
calculated to keep particle passage below a desired maximum.
[0019] This construction is beneficial in that because the
particles capable of reaching the outer layer of are a much smaller
size than those filtered out by the inner layer; clogging of the
openings of the outer layer is less likely to occur than if the bag
consisted of a single layer equivalent to the outer layer.
[0020] In should be understood that merely because the average
opening area of the openings of the outer layer is smaller than the
average opening area of the openings of the inner layer, it does
not mean that the total opening area of the openings (i.e. the sum
of the opening area of each of the openings) of the outer layer is
smaller than the total opening area of the openings of the inner
layer. Indeed, preferably, it is larger (i. e. the total opening
area of the openings of outer layer is greater than the total
opening area of the openings of the inner layer). In this manner,
control of the air flow through the filtering chamber and out of
the bag is controlled by the total opening area of the openings of
the inner layer. Thus depending on the application of the bag, a
desired airflow can be created or controlled by increasing or
decreasing the size and/or number of openings in the inner
layer.
[0021] It is not required that the inner-layer openings and the
outer-layer openings be on the same face of the bag. They may be on
different faces. For example, it may be that the left side face
inner layer has openings and the front face outer layer has
openings. What is important is that there be some pathway for air
to egress the interior of the bag passing through both the openings
of the inner layer and the openings of the outer layer; the
intermediate spaces of 2-ply areas (of the left side inner layer
and the front face outer layer - from the previous example) thus
must be fluidly connected. It may be that in such situations no
other faces of the bag have layers with openings. Alternatively, it
may that there are other faces that do have openings, but that
their intermediate spaces are not in fluid communication with the
faces in question (the left side inner layer and the front face
outer layer--from the previous example), and thus they provide for
filtering chambers that are fluidly distinct from others on the
bag.
[0022] Nonetheless, for most applications it is preferred that the
first face and the second face are the same face of the bag and
that the first intermediate space and the second intermediate space
are the same intermediate space. I.e. it is the inner layer and the
outer layer of the same face that have openings and a filtering
chamber is formed directly therebetween.
[0023] In such cases, it is highly preferred that the openings of
the outer layer be offset from the openings of the inner layer.
This will discourage the openings of the outer layer from becoming
clogged with particles or having particles become lodged therein.
Particles travelling through the openings of the inner layer will
impact on the material of the outer layer itself and will
(hopefully) ricochet back into the filter chamber where they will
harmlessly remain trapped. This is contrasts with the situation
where particles travelling through the inner layer would be
directed (with some force) directly towards an opening in the outer
layer, greatly increasing the chances that the outer-layer opening
will become clogged.
[0024] It is further preferred that in the absence of air and
particulate matter in the filtering chamber the outer layer of the
second face and the inner layer of the first face lie flat against
one another.
[0025] It is also highly preferred that the plastic bag further
comprises: a third face, at least a portion thereof being 2-ply and
having a third intermediate space therebetween, the 2-ply portion
of the third face having an inner layer of air-impervious plastic
material having openings therein permitting air to pass
therethrough; a fourth face, at least a portion thereof being 2-ply
and having a fourth intermediate space therebetween, the 2-ply
portion of the fourth face having an outer layer of air-impervious
plastic material, the outer layer having openings therein
permitting air to pass therethrough, the openings of the outer
layer having a smaller average opening area than an average opening
area of the openings of the inner layer of the third face, the
third intermediate space and the fourth intermediate space being
fluidly interconnected; whereby a second filtering chamber is
formed between the inner layer and the outer layer such that air in
an interior of the bag may egress the bag by passing through the
openings of the inner layer and through the openings of the outer
layer, the air being at least partially filtered of particulate
matter as it egresses the bag.
[0026] As was previously described hereinabove with respect to the
first and second faces, it is not required that the third-face
inner-layer openings and the fourth-face outer-layer openings be on
the same face of the bag. They may be on different faces.
Nonetheless, for most applications it is preferred that the third
face and the fourth face are the same face of the bag and that the
third intermediate space and the fourth intermediate space are the
same intermediate space. I.e. it is the inner layer and the outer
layer of the same face that have openings and a filtering chamber
is formed directly therebetween. In such cases, it is highly
preferred that the openings of the outer layer be offset from the
openings of the inner layer as was also described hereinabove.
[0027] It should be understood that there may or may not be any
correlation between the first, second, third and fourth faces. That
is to say that none, some or all of the faces may be the same face.
Further, their intermediate spaces may or may not be fluidly
connected (provided at least one pathway for air to egress the
interior of the bag is provided). Thus, many different
constructions within the scope of the present invention are
possible.
[0028] By way of non-limiting example, it may be that all of the
faces are the same face, yet the first and second intermediate
spaces are not fluidly connected with the third and fourth
intermediate space. Thus two independent filtering chambers would
be formed on the same face. Alternatively, it may be that only the
second and third face are the same face. In such as case, the first
and second intermediate spaces may or may not be fluidly connected
with the third and fourth intermediate spaces such that one or more
than one filtering chamber will be formed.
[0029] For most applications it is preferred that the first
intermediate space, the second intermediate space, the third
intermediate space, and the fourth intermediate space are all
fluidly interconnected forming such that the first filtering
chamber and the second filtering chamber are the same filtering
chamber. This will maximize the chances of air egressing the
interior of the bag as many pathways will be formed.
[0030] It is highly preferred that the layers with openings therein
be the front face and rear face inner layer and the front face and
the rear face outer layer. Where such is the case, it is also
preferred that no other layer of any other face have openings. Bags
of the present invention are likely destined to be palletized for
transport and distribution. Where this is the case, they will be
laid on the pallet (or on another bag lower down on the pallet)
either on their front face or on their rear face, such that the
material in the bag will lie on the face of the bag facing the
pallet (or the bag below as the case may be) and the air will rise
to the above and be permitted to egress the bag through the filter
chamber described hereinabove. If both the front faces and rear
faces of all layers of the bag having openings, it is not necessary
for the person placing the bag to ensure that a particular face is
oriented in a particular direction; either face may be face-up,
simplifying packing operations.
[0031] In such cases, it is highly preferred that the bag have no
structure that would keep the layers of the faces in a spaced-apart
relationship, i.e. in the absence of air and/or particulate matter
in the filter chamber, the outer layer and the inner layer should
lie flat against one another (i.e. be touching such that there is
no volume therebetween). The openings of the outer layer being
misaligned with the openings of the inner layer will cause the
openings of the inner layer to be blocked by the outer layer when
the two layers are in contact. This is desirable to occur in the
scenario described above for the face-down face of the bag. In this
manner, the face-down face of the bag is sealed by the weight of
the material in the bag, and the air will have to pass through the
openings in the face-up face of the bag (the overpressure of air
will force the inner and outer layers to separate and create the
filter chamber). When the next bag is placed on top of the bag on
the pallet, the weight of material in the second bag will then seal
(at least until that bag is removed) both its own face-down face
and the face-up face of the bag on which it was placed. This will
have the effect of sealing the first bag (ideally completely) so as
to prevent moisture from re-entering the bag through any of the
openings. In situations where this described occurrence is desired,
it is preferred that none of the other faces of the bags have
openings so that the bags may be completely sealed once stacked on
one another.
[0032] It is also preferred the openings of the inner layer (of
whatever face) have a jagged edge (i.e. a jagged-edge that opens
inward toward the interior or outward away from the interior of the
bag). It has been found that this structure will discourage
particles from clogging the openings of the inner layer. Jagged
edges may be formed by any suitable method.
[0033] It should be understood that bags of other physical
constructions are within the scope of the present invention. In
this respect, it is not necessary that bags of the present
invention be completely 2-ply (i.e. that each and every one of
their faces is 2-ply). Also possible is a construction where only a
portion or portions of the bags are 2-ply. The portion or portions
may be on a single face or may be on multiple faces. Where the
later is the case, it is not necessary that the portion of the
inner layer having openings and the portion of the outer layer
having openings be on the same face. It may be that these portions
are remote from one another and it also may be that they are on
different faces. What is important is that there be some pathway
for air to egress the interior of the bag; the intermediate spaces
of 2-ply areas must be fluidly connected.
[0034] For some applications (particularly those requiring
cleanliness), it may be preferred that the openings of the outer
layer are arranged with respect to each other such that the outer
layer of the bag may be ripped apart (and removed from the bag)
along a tear line including such openings. In such cases, the
openings of the outer layer are preferably serrations (that may be
easily torn) running across the length of the bag. In this manner,
it may not be necessary to ship and store the bag in any particular
fashion. The outer layer will be exposed to the environment but the
inner layer will not. At an appropriate time, the outer layer may
be removed and the clean inner layer and its contents may be used
as desired.
[0035] In another aspect, as embodied and broadly described herein,
the present invention also provides a multi-ply plastic bag
comprising: an inner layer of air-impervious plastic material, at
least a portion of which has openings therein permitting air to
pass therethrough; an intermediate layer of air-impervious plastic
material, at least a portion of which has openings therein
permitting air to pass therethrough; and an outer layer of
air-impervious plastic material, at least a portion of which has
openings therein permitting air to pass therethrough.
[0036] It is preferred that the openings of the outer layer have an
average opening area that is smaller than an average opening area
of the openings of the intermediate layer; and the average opening
area of the openings of the intermediate layer is smaller than an
average opening area of the openings of the inner layer, whereby a
filtering chamber is formed such that air in an interior of the bag
may egress the bag by passing through the openings of the inner
layer, through the openings of the intermediate layer, and through
the openings of the outer layer, the air being at least partially
filtered of particulate matter as it egresses the bag.
[0037] It is further preferred that the openings of the outer layer
are offset from the openings of the intermediate layer; and the
openings of the intermediate layer are offset from the openings of
the inner layer. It also preferred that in the absence of air and
particulate matter in the filtering chamber, the outer layer, the
intermediate layer and the inner layer lie flat against one
another. It is still also preferred that the total opening area of
the openings of outer layer and the total opening area of the
openings of the intermediate layer are each individually greater
than the total opening area of the openings of the inner layer.
[0038] Preferably, as described herein above in relation to other
aspects of the invention, the plastic bag has a plurality of faces
including a front face and a rear face, and the openings are
located solely on the front face and the rear face of the bag.
Further, the inner-layer openings have a jagged edge and the
outer-layer openings have a non-jagged edge.
[0039] Embodiments of the present invention each have at least one
of the above-mentioned objects and/or aspects, but do not
necessarily have all of them. It should be understood that some
aspects of the present invention that have resulted from attempting
to attain the above-mentioned objects may not satisfy these objects
and/or may satisfy other objects not specifically recited
herein.
[0040] Additional and/or alternative features, aspects, and
advantages of the embodiments of the present invention will become
apparent from the following description, the accompanying drawings,
and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] For a better understanding of the present invention, as well
as other aspects and further features thereof, reference is made to
the following description which is to be used in conjunction with
the accompanying drawings, where:
[0042] FIG. 1 is a front elevation view of an unfilled bag of a
first embodiment of the present invention;
[0043] FIG. 2 is cross-sectional view of the bag of FIG. 1 taken
along the line 2-2 therein;
[0044] FIG. 3 is a rear left perspective view of a filled bag of
FIG. 1;
[0045] FIG. 4 is a close-up top plan view of the front surface of
the inner layer of the bag of FIG. 1;
[0046] FIG. 5 is a close-up top plan view of an opening on the
front surface of the inner layer of the bag of FIG. 1;
[0047] FIG. 6 is a cross-sectional view of the opening of FIG.
5;
[0048] FIG. 7 is a close-up top plan view of the front surface of
the outer layer of the bag of FIG. 1;
[0049] FIG. 8 is a close-up top plan view of an opening on the
front surface of the outer layer of the bag of FIG. 1;
[0050] FIG. 9 is a cross-sectional view of the opening of FIG.
8;
[0051] FIG. 10 is top plan view showing a comparison of the
openings of FIGS. 5 and 8;
[0052] FIG. 11 is close-up cross sectional view of the front
surfaces of the inner and outer layers of the bag of FIG. 1,
showing the offset of the openings therein;
[0053] FIG. 12 is a schematic cross-sectional view of a filled bag
of the present invention on a pallet;
[0054] FIG. 13 is a close-up cross sectional view of the front
surfaces of the inner and outer layers of the bag of FIG. 12,
showing the action of the filtering chamber therebetween;
[0055] FIG. 14 is a close-up cross sectional view of the rear
surfaces of the inner and outer layers of the bag of FIG. 12;
[0056] FIG. 15 is a close-up cross sectional view of the front
surfaces of the inner and outer layers of the bag of FIG. 12 as
well the rear surfaces of the inner and outer layers of a second
bag of similar construction placed on top of the bag of FIG. 12 on
the pallet;
[0057] FIG. 16 is a front elevation view of a bag of a second
embodiment of the present invention;
[0058] FIG. 17 is cross-sectional view of a bag of a third
embodiment of the present invention;
[0059] FIG. 18 is close-up cross sectional view of the bag of FIG.
17;
[0060] FIG. 19 a top plan view showing a comparison of the openings
of FIG. 18;
[0061] FIG. 20 is a front elevation view of an unfilled bag of a
fourth embodiment of the present invention; and
[0062] FIG. 21 is a close-up top plan view of the front surface of
the inner layer of the bag of FIG. 20.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0063] In FIG. 1 of the present invention there is shown a bag 10
similar (albeit constructed according to the teachings of the
present invention) to one described in the '005 publication. It
should be understood that this bag is described herein only as a
preferred embodiment. Other embodiments are possible in accordance
with the teachings of the present invention.
[0064] In FIG. 1, bag 10 (collapsed) has a top face 12 and a bottom
face 14, left- and right side gussets 16' and 16, respectively,
with left- and right-side center gusset creases 18' and 18
respectively. (For ease of understanding, it should be noted that
the left side of the bag is closer to the right edge of the drawing
page (and vice versa), as it is the bag's left, and not the viewer
of the drawing's left, that is being referred to.) Extending inward
from the right-side center gusset crease 18 are internal flap edges
20 and 22 (the latter not shown in FIG. 1 as it lies directly
underneath internal flap edge 20). Internal lap sealed portion 24
(the shaded strip) is the narrow strip of material in between
right-side center gusset crease 18 and internal flap edges 20 and
22, and runs continuously from bag top 12 to bottom 14. As viewed,
the lap sealed portion 24 lies inside of the bag 10 adjacent to the
right-side center gusset crease 18, and the lap seal defining
right-side center gusset crease 18. With the lap seal facing
inward, inside the bag, the outer surface of the bag has no ridges
or seals pointed outward.
[0065] As can be seen in FIG. 2, bag 10 is of a 2-ply construction,
having an outer layer 40 and an inner layer 42. (The 2-ply nature
of the bag 10 is not shown in FIG. 1 simply for ease of
understanding.) The outer layer and the inner layer may be of
plastic material suitable for the intended use of the bag.
Thermoplastic resins blends such as polyolefin resin blends and
polyethylene resin blends are non-limiting examples of preferred
materials.
[0066] The bag 10 has front face 26 and a rear face 28. The front
face 26 has an outer layer 26o (being a portion of the outer layer
40) and an inner layer 26i (being a portion of the inner layer 42).
Similarly, the rear face 28 has an outer layer 28o (being a portion
of the outer layer 40) and an inner layer 28i (being a portion of
the inner layer 42).
[0067] The bag 10 also has a right side face 31 and a left side
face 35. The right side face 31 has an outer layer 31o (being a
portion of the outer layer 40) and an inner layer 31i (being a
portion of the inner layer 42). The right side face outer layer 31
o is formed from a right side front gusset outer layer 30o, a right
side rear gusset outer layer 32o, and a right side center gusset
crease 18. The right side face inner layer 31i is formed from a
right side front gusset inner layer 30i, a right side rear gusset
inner 32i, and the right side center gusset crease 18. The left
side face 35 has an outer layer 35o (being a portion of the outer
layer 40) and an inner layer 35i (being a portion of the inner
layer 42). The left side face outer layer 35o is formed from a left
side front gusset outer layer 34o and a left side rear gusset outer
layer 36o. The left side face inner layer 35i is formed from a left
side front gusset inner layer 34i and a left side rear gusset inner
36i. (For ease of understanding there is a gap shown in FIG. 2
between the inner layer 42 and the outer layer 40 layers of the bag
10. It should be understood however, that ideally there is no such
gap when the bag 10 is flat and unfilled. The gap illustrates
intermediate spaces associated with of the various layers of the
faces. For example, there is an intermediate space 46o associated
with the front face outer layer 26o, an intermediate space 46i
associated with the front face inner layer 26i, an intermediate
space 48o associated with the rear face outer layer 28o, and an
intermediate space 48i associated with the rear face inner layer
28i. These intermediate spaces will form part of the filtering
chamber 44, best shown in FIG. 13.)
[0068] In between the right side center gusset crease 18 and
internal flap edges 20 and 22 is internal lap-sealed portion 24.
(The lap-sealed portion sealing the inner layer 42 and outer layer
40 together, each of these portions of the bag is labelled as a
single common portion.) This lap-sealed portion may be a strip as
narrow as 3 mm or may be wider.
[0069] In FIG. 3 bag 10 has been filled with a flowable material
(air and material mixture under pressure) and sealed at the top
edge 12. Right side center gusset crease 18 is one continuous
crease formed by the internal lap-sealed portion 24 (the latter not
shown since it is inside bag 10). The outer appearance of center
gusset crease 18 looks much like that of any other side gusset
crease commonly seen in standard tube-type bags, that is, one
clean, continuous fold.
[0070] Referring still to FIGS. 1 to 3, there are marked areas (27
in FIGS. 1 & 3) on the front face outer layer 26o (marked area
being 27o in FIG. 2), front face inner layer 26i (marked area being
27i in FIG. 2), rear face outer layer 28o (marked area being 29o in
FIG. 2), and rear face inner layer 28i (marked area 29i in FIG. 2).
These areas have openings therein (described hereinbelow), although
the openings have been omitted in these figures for ease of
illustration.
[0071] FIG. 4 shows a close-up view of the marked area 27i of front
surface inner layer 26i. Openings 25i can be seen. The openings are
preferably slits being 500 microns long and 100 microns wide. The
openings 25i are shown at a regularly-spaced intervals (which is
preferably along a grid 1.25 cm apart in both directions), but this
is merely a preferred configuration. FIG. 5 shows a close-up view
of single opening 25i shown in FIG. 4. The opening 25i is irregular
in shape, again this being a preferred configuration. Finally, FIG.
6 shows a cross-sectional view of the opening 25i of FIG. 5. The
opening 25i has an (outwardly) jagged edge 33i. The marked area 29i
of the rear surface inner layer 28i has similar openings.
[0072] FIG. 7 shows a close-up view of the marked area 27o of front
surface outer layer 26o. Openings 25o can be seen. The opening are
preferably circular and have a diameter of between 20 and 100
microns, with 50 microns being most preferred. The openings 25o are
shown at a regularly-spaced intervals (which is preferably along a
grid 5 mm apart in both directions), but this is merely a preferred
configuration. FIG. 8 shows a close-up view of single opening 25o
shown in FIG. 7. The opening 25o is regular in shape, again this
being a preferred configuration. Finally, FIG. 9 shows a
cross-sectional view of the opening 25o of FIG. 8. The opening 25o
has a smooth edge 33o. The marked area 29o of the rear surface
outer layer 28o has similar openings.
[0073] FIG. 10 shows the relative size difference between the
openings 25i of the inner layer 26i/28i and the openings 25o of the
outer layer 26o/28o.
[0074] FIG. 11 shows the relative positioning of the openings 25i
of the rear face inner layer 28i and the openings 25o of the rear
face outer layer 28o. As can be seen, the openings 25i are offset
from the openings 25o.
[0075] FIG. 12 shows a bag 10 that has been filled with particulate
material 37 and has been placed on a palette rear face 28 down.
(The filling of the bag could have been by any conventional means,
including those described in the '005 publication.). Air is
entrapped within the particulate matter 37. FIG. 13 shows a
close-up of the front face of the bag. As can be seen, particulate
matter 37 is made up a particles of different sizes, for ease of
illustration shown as large particles 37a, medium particles 37b,
and small particles 37c. Air under pressure inside the bag a result
of the filling of the bag, will flow out of the bag in the path
shown, first through an opening 25i of the front face inner layer
26i and into filter chamber 44 between the front face inner layer
26i and the front face outer layer 26o (the air will force the
inner layer 26i and the outer layers 26o apart to create the filter
chamber 44) and then from the filter chamber 44 through an opening
25o of the front face outer layer 26o to the environment. As can be
seen, the opening 25i is of such as size so as to prevent large
particles 37a from entering the filter chamber 44. Further, opening
25o is of such as size so as to prevent medium particles 37b from
exiting the filter chamber. (Those particles will remain in the
filter chamber 44 or flow back into the interior of the bag 10
through an opening 25i.) Only small particles 37c are of a size
that can exit the bag 10 through the opening 25o (and only then if
they actually reach the opening 25o. Some will impact the outer
layer 26o and be deflected into the filter chamber 44 to a point
where they cannot reach an opening 25o). In this manner, air is
filtered as it exists the bag 10.
[0076] FIG. 14 shows a close-up of the rear face 28 of the bag 10
of FIG. 12. The weight of the particles 37 maintains the rear face
outer layer 28o and rear face inner layer 28i together such the
openings 25i and 25o are effectively sealed on that face 28. (The
edge 33i of the opening 25i of the rear face inner layer 28i has
collapsed into the opening 25i.) No filter chamber is formed and no
air can escape the bag through the rear face 28 of the bag.
[0077] FIG. 15 shows a close up of the front face 28 of the bag 10
after a second bag 10' has been placed on top. In this case, the
weight of the second bag 10' helps to seal and discourage moisture
from entering the first bag 10 as it forces the front face of the
outer layer 28o of the first bag 10 against the front face inner
layer 28i of the first bag 10, sealing off the openings 25i/25o.
(Some small 37c and medium particles 37b remain trapped between the
layers.) In addition, adding to this effect, the rear face outer
layer 28o' of the second bag 10' blocks off the openings 25o of the
front surface the outer layer 28o of the first bag 10.
[0078] FIG. 16 shows a second embodiment of the present invention,
a gusset valve bag 210. Valve bag 210 is similar to the previously
described first embodiment of the present invention gusset bag 10,
with the exception of the presence of a valve portion similar to
that found on conventional paper valve bags. In valve bag 210,
internal lap-sealed portion 224 (shaded portion) is a narrow sealed
strip that lies adjacent to side center gusset crease 218 and
spaced from internal flap edges 250, but runs continuously only
from bag bottom face 214 up to a point 256 where it stops. Valve
opening 258 is the unsealed portion that lies along the center
gusset crease 218 in between point 256 and bag top face 212, and is
suitable for allowing entry of a fill nozzle much like those used
to fill standard paper valve bags. With valve opening 258
positioned at the center gusset crease, it is easy and natural for
the user to find the valve opening 258 of bag 210 and mount it on a
fill nozzle. In between lap-sealed portion 254 and valve opening
258, and internal flap edges 250, lie internal flap portions 260
that run continuously from bag top face 212 to bag bottom face 214.
Typically flap portions 260 may extend inward, inside bag 210,
about 5 cm to 7.5 cm depending on bag size, but could be more or
less. Horizontal seal 264 begins at point 256 and runs
approximately horizontally into internal flap portions 260. The
area in between horizontal seal 264 and sealed bag top 212 forms a
valve sleeve 265, which sleeve, along with valve opening 258,
typically measure about the same overall circumference, or slightly
greater, as an existing prior art fill nozzle. Thus, valve opening
258 and valve sleeve 265 may be mounted onto a fill nozzle with a
reasonably snug fit, preventing leakage as the bag is filled, and
subsequently collapsing upon itself after filling, so that the
flowable material contained inside will not leak out. In other
respect, for instance the presence of openings in area 227, the bag
210 is similar to bag 10 of the first embodiment.
[0079] FIG. 17 shows a third embodiment of the present invention,
multi-ply bag 310. As can be seen in FIG. 17, bag 310 is of a 3-ply
construction, having an outer layer 340, an inner layer 342, and an
intermediate layer 341 therebetween. The bag 310 has front face 326
and a rear face 328. The front face 326 has an outer layer 326o
(being a portion of the outer layer 340), an intermediate layer
326m (being a portion of the intermediate layer 341) and an inner
layer 326i (being a portion of the inner layer 342). Similarly, the
rear face 328 has an outer layer 328o (being a portion of the outer
layer 240), an intermediate layer 328m (being a portion of the
intermediate layer 341) and an inner layer 328i (being a portion of
the inner layer 342).
[0080] The bag 310 also has a right side face 331 and a left side
face 335. The right side face 331 has an outer layer 331o (being a
portion of the outer layer 340), an intermediate layer 331m (being
a portion of the intermediate layer 341) and an inner layer 331i
(being a portion of the inner layer 342). The right side face outer
layer 331o is formed from a right side front gusset outer layer
330o, a right side rear gusset outer layer 332o, and a right side
center gusset crease 318. The right side face intermediate layer
331m is formed from a right side front gusset intermediate layer
330m, a right side rear gusset intermediate layer 332m, and a right
side center gusset crease 318. The right side face inner layer 331i
is formed from a right side front gusset inner layer 330i, a right
side rear gusset inner 332i, and the right side center gusset
crease 318. The left side face 335 has an outer layer 335o (being a
portion of the outer layer 340), an intermediate layer 335m (being
a portion of the intermediate layer 341) and an inner layer 335i
(being a portion of the inner layer 342). The left side face outer
layer 335o is formed from a left side front gusset outer layer 334o
and a left side rear gusset outer layer 336o. The left side face
intermediate layer 335m is formed from a left side front gusset
intermediate layer 334m and a left side rear gusset intermediate
layer 336m. The left side face inner layer 335i is formed from a
left side front gusset inner layer 334i and a left side rear gusset
inner 336i. (In FIG. 17 the layers are shown as flat and lying
together with no gap therebetween. This is the preferred state
before the bag is filed.
[0081] In between the right side center gusset crease 318 and
internal flap edges 320 and 322 is internal lap-sealed portion 324.
The lap-sealed portion sealing the inner layer 342, intermediate
layer 341, and outer layer 340 together. This lap-sealed portion
may be a strip as narrow as 3 mm or may be wider.
[0082] As shown in FIG. 18, when the bag 310 is filled and has air
entrapped therein, the inner layer 342 and the intermediate layer
341 will separate from each other forming an inner filter chamber
344i. Similarly the intermediate layer 341 and the outer layer 342
will separate from each other forming an outer filter chamber 344o.
Air will egress the bag by flowing from the interior into the inner
filter chamber 344i, then into the outer filter chamber 344o, and
finally to the environment. FIG. 18 also shows the relative
positioning of the openings 325i of the front face inner layer
326i, the openings 325m of the front face intermediate layer 326m,
and the openings 325o of the front face outer layer 326o. As can be
seen, the openings 325o are offset from the openings 325m and the
openings 325m are offset from the openings 325i.
[0083] FIG. 19 shows the relative size difference between the
openings 325i of the inner layer 342, the openings 325m of the
intermediate layer 341, and the openings 325o of the outer layer
340. The openings 325i of the inner layer 342 are preferably
irregularly-shaped slits being 500 microns long and 100 microns
wide, being formed by slicing with a spinning blade. They
preferably have an (outwardly) jagged edge 333i (FIG. 18). The
openings 325o of the outer layer 340 and the openings 325m of the
intermediate layer 341 are preferably circular and have a diameter
of between 20 and 100 microns (with openings 325m of the
intermediate layer 341 being larger than those 325o of the outer
lawyer 340), preferably being formed by needle perforation. They
preferably have an (outwardly) smooth edge 333o/333m. In this
manner the inner filter chamber 344i and outer filer chamber 344o
progressively filter air egressing the bag therethrough.
[0084] In FIG. 20, There is shown a bag 400 (collapsed) of a 2-ply
construction in accordance with a fourth embodiment. Bag 400 has a
top face 402 and a bottom face 404, a front face 401 and a rear
face 403 (not shown) which is identical to the front face 401, Bag
also has right- and left side gussets 406 and 406', respectively,
with right- and left-side center gusset creases 408 and 408'
respectively. Bag 400 has an outer layer 410 and an inner layer 412
(FIG. 21). The 2-ply nature of the bag 400 is not shown in FIG. 20
for ease of understanding. The inner layer 412 of the bag 400 is
micro-perforated with openings 414 having a diameter of between 20
and 100 microns, with 50 to 75 microns being the most preferred.
The outer layer 410 is not perforated but includes four serrations.
Each serration extending substantially the entire length of the bag
400 from the top face 402 to the bottom face 404. Specifically,
there is a first serration 416a extending the length of bag 400 on
the right side of the front face 401, a second serration 416b
extending the length of bag 400 on the left side of the front face
401, and two similarly positioned serrations on the right side and
the left side of the rear face 403 of the bag 400.
[0085] Bag 400 is destined to be used in a food application, where
a virtually impermeable (although not quite) outer layer 410 is
required to prevent dust from entering into the bag 400 at all. Air
evacuation is slower than previous embodiments since the inner
layer 412 includes micro-openings 414 of between 20 and 100 microns
and air can only evacuate through the serrations 416 of the outer
layer 410. The serrations 416 are preferably larger in size than
the openings 414. However, the openings 414 of the inner layer 412
could be larger than the serrations 416 for food products that are
not powdery such as grains and flakes.
[0086] The serrations 416 are designed so that the outer layer 410
can be removed just before the bag 400 is emptied. For example bags
400 is filled with a food product such as batter mix, then shipped
to a user and stored. When the bag 400 is ready to be used, it is
placed in a clean room where it is opened and the product is dumped
into the batch mix. Just before going into the clean room, an
operator rips the outer layer 410 of the front face 401 and the
rear face 403 along a tear line including the serrations 416,
removes outer layer 410 from the bag and discards it. The bag 400
is now clean since the inner layer 412 remains and it was never
exposed to the outside environment. The bag 400 is then brought
into the clean room, cut open and the product is dispensed into an
appropriate processor for processing.
[0087] A bag 400 provided with outer layer 410 including serrations
that allow removal of the outer layer 410 may be, for example,
either an open-mouth bag which is sealed after being filled or a
valve bag as previously described.
[0088] Modifications and improvements to the above-described
embodiments of the present invention may become apparent to those
skilled in the art. The foregoing description is intended to be
exemplary rather than limiting. The scope of the present invention
is therefore intended to be limited solely by the scope of the
appended claims
* * * * *