U.S. patent application number 11/214327 was filed with the patent office on 2005-12-22 for method of forming a vented bag.
This patent application is currently assigned to Exopack-Technology, LLC. Invention is credited to Allen, John R., Busbin, Richard Henry.
Application Number | 20050281494 11/214327 |
Document ID | / |
Family ID | 35480651 |
Filed Date | 2005-12-22 |
United States Patent
Application |
20050281494 |
Kind Code |
A1 |
Allen, John R. ; et
al. |
December 22, 2005 |
Method of forming a vented bag
Abstract
A multiwall vented bag is provided which includes an inner tube
formed of a plastic material. The inner tube has an open end
initially in an open position and adapted to receive filling
material therein and at least one vent opening formed therein. The
bag further includes a strip of material positioned adjacent and
attached to a preselected region of the inner tube. The preselected
region includes the at least one vent opening of the inner tube.
The strip also includes at least one vent opening to allow air to
pass from within the inner tube, through both the at least one vent
opening of the inner tube and the at least one vent opening of the
strip. The bag further includes an outer tube positioned to
substantially surround outer surfaces of the inner tube. The outer
tube is formed of a porous material that allows air released from
within the inner tube to pass out of the bag through porous
material of the outer tube. A method of forming and using a vented
bag are also included.
Inventors: |
Allen, John R.; (Tifton,
GA) ; Busbin, Richard Henry; (Chula, GA) |
Correspondence
Address: |
BRACEWELL & GIULIANI LLP
P.O. BOX 61389
HOUSTON
TX
77208-1389
US
|
Assignee: |
Exopack-Technology, LLC
Spartanburg
SC
29302
|
Family ID: |
35480651 |
Appl. No.: |
11/214327 |
Filed: |
August 29, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11214327 |
Aug 29, 2005 |
|
|
|
10421607 |
Apr 23, 2003 |
|
|
|
Current U.S.
Class: |
383/109 ;
383/101; 383/103; 383/111 |
Current CPC
Class: |
B65D 33/01 20130101 |
Class at
Publication: |
383/109 ;
383/101; 383/111; 383/103 |
International
Class: |
B65D 030/08; B65D
033/01 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. A method of forming a vented bag the method comprising:
perforating a tube of at least one ply of plastic material to form
a plurality of spaced apart vent openings in the tube; perforating
a separate plastic strip of material to form a plurality of spaced
apart vent openings in the plastic strip; and adhering the plastic
strip adjacent the tube in a preselected region to thereby form a
vented seal zone having a channel space formed between surfaces of
the plastic strip and the tube so that the combination of the
plurality of vent openings in the tube and the plurality of vent
openings in the plastic strip are positioned to not align so as to
create a tortuous path to reduce product sifting and insect
infestation when product is positioned within the tube and so that
air within the tube travels through both of the plurality of vent
openings in the tube and the plurality of vent openings in the
plastic strip.
27. A method as defined in claim 26, wherein the at least one ply
of plastic material of the tube comprises a continuous seamless,
tubular, plastic film, wherein the tube comprises an inner tube,
and the method further comprises attaching the inner tube to inner
surfaces of an outer tube formed of a porous material to
substantially surround the inner tube.
28. A method as defined in claim 27, wherein the plastic strip
extends substantially the entire longitudinal extent of inner tube,
and wherein the outer tube comprises a plurality of layers of
porous material so that air exiting the inner tube travels into the
porous material of the outer tube and then into atmosphere.
29. A method as defined in claim 28, further comprising heat
sealing an end of the tube defining a closed end of the inner tube
and heat sealing the channel space adjacent the closed end of the
inner tube.
30. A method as defined in claim 29, further comprising heat
sealing the open end of the inner tube and an upper end of the
channel space positioned adjacent the open end of the inner tube
after filler material is filled therein to a selected level to
thereby seal the open end of the inner tube and the upper end of
the channel space.
31. A method as defined in claim 30, the method further comprising
the step of severing the inner tube from the open end of the outer
tube to thereby form a sealed plastic pouch within a paper outer
bag.
32. A method as defined in claim 27, wherein the tube comprises an
inner tube, and the method further comprises forming an outer tube
positioned to substantially surround outer surfaces of the inner
tube, the outer tube having a closed end region, an open end region
being initially in an open position and adapted to receive filling
material therethrough, and an outer tube body extending between the
open end region and the closed end region and overlying the plastic
strip, the outer tube being formed by laminating a plurality of
stepped layers of a porous material.
33. A method as defined in claim 32, further comprising forming
selective regions of adhesive material between inner surfaces of
the closed end region of the outer tube body and outer surfaces of
the inner tube so that the closed end of the inner tube is
detachably adhered to the closed end region of the outer tube, so
that the inner tube remains adhered to the outer tube until after
the bag is filled to a selected level with filling material, and so
that a user of the bag can readily remove the inner tube from the
outer tube without damage to the inner tube when the inner tube has
filling material positioned therein, and wherein the porous
material comprises paper material.
34. A method of forming a vented bag, the method comprising:
positioning a plate member within a tube of at least one ply of
plastic material; and rotatingly perforating the tube with a
perforator roll positioned adjacent a first outer surface of the
plate member so that the plate member operates as a stop for the
perforator roll to prevent perforation of a second opposing outer
surface of the tube and yet allowing perforation of the first outer
surface of the tube to form a plurality of spaced apart vent
openings in the first outer surface of the tube.
35. A method as defined in claim 34, further comprising perforating
a separate plastic strip of material to form a plurality of spaced
apart vent openings in the plastic strip and adhering the plastic
strip adjacent the tube in a preselected region to thereby form a
vented seal zone having a channel space formed between surfaces of
the plastic strip and the tube so that the combination of the
plurality of vent openings in the tube and the plurality of vent
openings in the plastic strip are positioned to not align so as to
create a tortuous path to reduce product sifting and insect
infestation when product is positioned within the tube and so that
air within the tube travels through both of the plurality of vent
openings in the tube and the plurality of vent openings in the
plastic strip.
36. A method as defined in claim 34, wherein the at least one ply
of plastic material of the tube comprises a continuous seamless,
tubular, plastic film, wherein the tube comprises an inner tube,
and the method further comprises attaching the inner tube to inner
surfaces of an outer tube formed of a porous material to
substantially surround the inner tube.
37. A method as defined in claim 36, wherein the plastic strip
extends substantially the entire longitudinal extent of inner tube,
and wherein the outer tube comprises a plurality of layers of
porous material so that air exiting the inner tube travels into the
porous material of the outer tube.
38. A method as defined in claim 34, wherein the tube of at least
one ply of plastic material extends in a substantially horizontal
orientation between at least one pair of spaced-apart rollers
during travel in a preselected manufacturing direction, wherein the
plate member is positioned in the tube between the at least one
pair of spaced-apart rollers, and wherein the perforator roll
overlies the plate member between the at least one pair of
spaced-apart rollers and overlies a substantially horizontal
extending first outer surface of the tube to form the plurality of
spaced-apart vent openings therein.
39. A method as defined in claim 38, wherein the plate member
comprises a metal material and is positioned to be suspended within
the tube between the at least one pair of spaced-apart rollers to
thereby define a floating plate, and wherein the floating plate
travels within the tube between the at least one pair of
spaced-apart rollers in a suspended position when the tube is being
perforated with the perforator roll during travel between the at
least one pair of spaced-apart rollers.
40. A method as defined in claim 35, further comprising heat
sealing an end of the tube defining a closed end of the inner tube
and heat sealing the channel space adjacent the closed end of the
inner tube.
41. A method as defined in claim 40, further comprising heat
sealing the open end of the inner tube and an upper end of the
channel space positioned adjacent the open end of the inner tube
after filler material is filled therein to a selected level to
thereby seal the open end of the inner tube and the upper end of
the channel space.
42. A method as defined in claim 35, wherein the tube comprises an
inner tube, and the method further comprises forming an outer tube
positioned to substantially surround outer surfaces of the inner
tube, the outer tube having a closed end region, an open end region
being initially in an open position and adapted to receive filling
material therethrough, and an outer tube body extending between the
open end region and the closed end region and overlying the plastic
strip, the outer tube being formed by laminating a plurality of
stepped layers of a porous material.
43. A method as defined in claim 42, further comprising forming
selective regions of adhesive material between inner surfaces of
the closed end region of the outer tube body and outer surfaces of
the inner tube so that the closed end of the inner tube is
detachably adhered to the closed end region of the outer tube, so
that the inner tube remains adhered to the outer tube until after
the bag is filled to a selected level with filling material, and so
that a user of the bag can readily remove the inner tube from the
outer tube without damage to the inner tube when the inner tube has
filling material positioned therein, and wherein the porous
material comprises a paper material.
44. (canceled)
45. (canceled)
46. (canceled)
47. (canceled)
48. A method of forming a vented bag the method comprising:
perforating an inner tube of at least one ply of plastic material
to form a plurality of spaced apart vent openings in the inner
tube; perforating a separate plastic strip of material to form a
plurality of spaced apart vent openings in the plastic strip;
adhering the plastic strip adjacent the tube in a preselected
region to thereby form a vented seal zone having a channel space
formed between surfaces of the plastic strip and the tube so that
the combination of the plurality of vent openings in the tube and
the plurality of vent openings in the plastic strip are positioned
to not align so as to create a tortuous path to reduce product
sifting and insect infestation when product is positioned within
the tube and so that air within the tube travels through both of
the plurality of vent openings in the tube and the plurality of
vent openings in the plastic strip; and forming an outer tube from
a plurality of layers of porous material and to substantially
surround outer surfaces of the inner tube, the outer tube having a
closed end region, an open end region being initially in an open
position and adapted to receive filling material therethrough, and
an outer tube body extending between the open end region and the
closed end region and overlying the plastic strip.
49. A method as defined in claim 48, further comprising forming
selective regions of adhesive material between inner surfaces of
the closed end region of the outer tube body and outer surfaces of
the inner tube so that the closed end of the inner tube is
detachably adhered to the closed end region of the outer tube, so
that the inner tube remains adhered to the outer tube until after
the bag is filled to a selected level with filling material, and so
that a user of the bag can readily remove the inner tube from the
outer tube without damage to the inner tube when the inner tube has
filling material positioned therein.
50. A method as defined in claim 48, wherein the porous material
comprises paper material, and wherein the plurality of layers
comprises a plurality of stepped layers of paper material.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to the packaging
industry. In more specific aspects, the present invention relates
to multiwall packaging and methods for forming multiwall packaging
that have vents associated therewith.
[0003] 2. Description of the Related Art
[0004] As more and more industrial, commercial, and consumer
products are packaged, the need for enhanced end product packaging
continues to grow. End product packaging not only has to keep the
products fresh, the product packaging often needs to protect the
environment from the product contents and protect the product
contents from the environment. The packaging must also be strong
enough to hold materials of varying weights, without being damaged,
in order to provide packaging for a vast array of consumer
products.
[0005] Of particular importance is often the ability to extract the
contents of a package such as a bag without contaminating the
contents with a contaminated outer surface of the bag. Various bags
have been developed in attempts to satisfy this requirement. The
typical bag includes integrated inner and outer plies, a flexible
sheet material formed into a tubular form, and the tubular form
being converted into an open mouth bag. At least one ply of the
flexible sheet material for the bag can be coated with a moisture
impervious plastic coating, laminated with a waterproof material,
or be formed of a waterproof material. One such bag, for example,
can be seen in U.S. Pat. No. 4,088,264 by Vogt titled "Multiwall
Pouch Bags Or Detached Packaging Of Commodities." The bag is formed
by first heat sealing and severing an inner plastic tube from an
outer paper tube to form a pouch of the inner tube. The inner tube
is attached to the outer tube only at the open bag end. The outer
plies are closed at a distance below the sack in a sewn or pinch
bottom closure to close the bag at the closed end. After the bag is
filled at the open end with a commodity to be packaged, the inner
pouch into which the commodity is loaded is heat sealed to closure
adjacent the open end and also severed from that end in a manner
similar to severing the lower end of the inner pouch. As packaged,
the commodity is contained within a sealed, sift and leak proof,
inner pouch which is housed within a sealed outer tube for
protection against environmental concerns such as contamination and
insect penetration. A significant difficulty arises, however, when
air is trapped in the inner pouch of the bag prior to sealing.
[0006] In such situations, it is important to permit air or gas
release after the bag has been packed and the open end of the bag
and the plastic pouch or poly liner have been sealed. It is also
important to prevent contamination due to the venting of the
trapped air. Applicants have recognized that when the plastic liner
inside an unvented bag is sealed after being filled, it traps air
and causes the bag to be difficult to handle and stack. The
unvented bags essentially have a balloon affect after being sealed.
There is also the risk that end seals in unvented bags will rupture
during stacking processes due to excess pressure being applied.
This problem is accentuated where the facility filling the bags is
located at a different pressure altitude than a destination
facility. Vents made by piercing a single ply plastic pouch or
liner have been found to be ineffective as they allow material to
sift out and insects to infest the material inside which often
consists of food or pharmaceutical grade product. To allow venting
of trapped air, others have developed various types of bags with
various methodologies of venting.
[0007] Some of the first attempts included perforating the bag with
very small holes in order to vent the trapped air. For example,
U.S. Pat. No. 2,593,328 by Meaker titled "Perforated Multiple Ply
Bag" describes a waterproof bag formed of electrically perforated
paper. Each of the plies that form the body of the bag is
electrically perforated to provide minute burrless perforations
through which air trapped in the bag during filling may escape. The
perforations are small enough to prevent the commodity with which
the bag is filled from passing through the perforations or outside
water from entering such perforations.
[0008] Another methodology includes using a single vent valve-type
bag. For example, U.S. Pat. No. 3,958,749 by Linder et al. titled
"Bacteria Proof Plastic Bag For Articles To Be Sterilized"
describes a bag having a single valve which is gas and steam
permeable at increased temperatures and which closes at a given
normal temperature so that no bacteria can enter. The valve
includes a filter device formed of a layer of water-soluble
adhesive, a gas permeable layer, and a heat resistant adhesive
having a plurality of holes. Also, U.S. Pat. No. 3,989,182 by
Stearley titled "Vented Bag" describes a bag including a valve
member which is positioned between one of the end flaps of the
overlapped side flaps and a plurality of venting perforations
formed in one of the end walls for providing venting of the
interior of the bag to the atmosphere.
[0009] Yet another methodology developed has been the formulation
of the bag using overlapping perforated margins from a continuous
web of flexible plastic material. For example, U.S. Pat. No.
3,302,859 by Perry titled "Bag" describes a bag having a
longitudinal seam including overlapping margins of plastic material
from which a tube is formed. The margins are secured together using
two spaced longitudinal seams of adhesive. Each margin has a series
of tongues for the escape of air from the bag whereby the tongues
in one margin are offset from the tongues in the other. U.S. Pat.
No. 4,470,153 by Kenan titled "Multiwall Pouch Bags with Vent
Strip" expanded on this design. The Kenan patent describes a bag
having an interior plastic pouch formed from a sealed plastic tube
having a longitudinal seam created by overlapping tube margins. The
margins forming the longitudinal seam are secured together using
two spaced-apart longitudinal seams of adhesive placed on opposite
sides of a filter type spacer. The inner margin has a series of
holes that allow air to escape from inside the interior plastic
pouch into a channel formed between the inner and outer margins.
Air escapes from the channel either through a set of holes in the
outer margin or through a heat seal closure. Also, U.S. Pat. No.
4,550,441 by Keppel titled "Vented Bag" further developed this
methodology. The Keppel patent describes a multiwall commodity bag
as an improvement upon U.S. Pat. No. 4,470,153 by Kenan where in
lieu of a series of vent holes or openings along one or both of the
overlapped margins of the channel, a small hole the size of a
pinhole is formed through the inner side of the center of the
overlap forming the channel near one end. A small hole is also
formed through the outer side and near the center of the channel
adjacent the other or opposite end of the plastic pouch. Applicants
have recognized that these type of seamed bags, however, can have
problems with seam overlap alignment and can be complex to
manufacture.
[0010] Also, bags have been developed that attempt not only allow
the protection of the contents from contamination yet are capable
of releasing trapped air, and allow for the extraction of the
contents without contaminating the contents with a contaminated
outer surface of the bag, but bags that are also easy to load,
stack, and palletize. These bags are typically formed using a pinch
bottom whereby the commodity-holding pouch is formed from an inner
plastic ply that is heat sealed at the pinch closure of the outer
enclosing bag and open at the opposite end for receipt of a product
to be packaged. Upon filling the bag to the desired amount, the
inner plastic ply is heat sealed to close the open end and may
remain attached or optionally be severed from the top end of the
outer plies using a pair of beveled compression rollers. Applicants
have recognized that additional problems can be encountered with
this type of bag arrangement, however. For example, often the
unfilled inner plastic bag in the standing position is much shorter
in length than the enclosing outer paper bag. This can cause uneven
or excessive pressures on the lower plastic seal creating a
potential for seal failure or pinholing. Some attempts to solve
this problem were made as seen in U.S. Pat. No. 5,281,027 by Thrall
titled "Multiple Ply Bag with Detachable Inner Sealed Pouch for
Packaging Products" which describes using a seamless inner heat
sealable ply that is as long as the outer paper bag during the
filling process and that is freely folded and fully detachable in a
non-adhesive manner at the bottom end of the pinch bottom bag.
Additionally, U.S. Pat. No. 5,553,943 by Cook et al. titled
"Multiple Ply Plastic Line Bag with Satchel Bottom" describes using
a seamless inner plastic pouch capable of heat sealing wherein the
plastic pouch is foldably, non-adhesively and detachably arranged
at the satchel bottom of the bag. The satchel bottom is formed by
slitting, folding, and overlapping stepped paper plies adhesively
bonded to form the satchel bottom and to loosely retain the pouch
independently and away from the adhesive bond. Applicants have
recognized that there is still a need, however, for alternative
type vented bags and packaging that addresses problems associated
with products sifting and insect infestation and yet is easy and
cost effective to manufacture.
SUMMARY OF THE INVENTION
[0011] In view of the foregoing, an embodiment of the present
invention advantageously provides a multiwall vented bag and
associated methods that allow a vented bag to be easily constructed
and yet substantially reduces the risk of filler material sifting
from the bag and of insects infesting the bag through vents in the
bag. An embodiment of the present invention also advantageously
provides a multiwall vented bag that enhances stacking ability and
yet allows air trapped in the bag to be readily vented therefrom.
An embodiment of the present invention further advantageously
provides end product packaging that is sealable and includes a
vented assembly built onto and inner tube formed of plastic
material that permits air release after the bag is packed and an
open end of the bag and a plastic pouch have been sealed. An
embodiment of the present invention also advantageously provides a
multiwall vented bag of tubular form having a continuous unseamed
tube body to enhance manufacturing and handling and to enhance
reliability. Further embodiments of the present invention
advantageously provide user friendly bags capable of holding
products of varying weights, that are strong and durable, that
provide consumers with a venting capability that will allow air
release to accommodate the handling and stacking the bag for
shipment, will reduce the possibility of product leakage or
infestation, and will be cost effective and easy to
manufacture.
[0012] More particularly, a multiwall bag according to an
embodiment of the present invention is provided which includes an
inner tube formed of a plastic material and having an open-end, a
closed end positioned opposite the open end, an inner tube body
extending between the open end and the closed end initially in an
open position and adapted to receive filling material therethrough,
and a plurality of spaced-apart inner vent openings formed in the
inner tube body. The bag also includes a plastic strip overlying
and adhering to a preselected region of the inner tube body and
positioned to overlie the plurality of spaced-apart inner vent
openings. The plastic strip extends substantially the entire
longitudinal extent of tube body and includes a plurality of
spaced-apart outer vent openings to allow air to pass from within
the inner tube body, through the plurality of space-apart inner
vent openings, and through the plurality of spaced-apart outer vent
openings. The combination of the plastic strip and the preselected
region of the inner tube body define a vent seal zone. The vent
seal zone includes a channel space positioned between an inner
surface of the plastic strip and an outer surface of the inner tube
body. The channel space also allows air to flow therethrough and
extends between the plurality of spaced-apart inner vent openings
and the plurality of spaced-apart outer vent openings so that the
plurality of spaced-apart inner vent openings and the plurality of
spaced-apart outer vent openings are not aligned and thereby form a
tortuous path to significantly reduce the risk of insect
infestation and to significantly reduce product sifting when
product is positioned in the bag. The bag further includes an outer
tube positioned to substantially surround outer surfaces of the
inner tube. The outer tube has a closed end region positioned
closely adjacent the closed end of the inner tube, an open end
region positioned closely adjacent the open end of the inner tube,
positioned initially in an open position, and adapted to receive
filling material therethrough, and an outer tube body extending
between the open end region and the closed end region and overlying
the plastic strip. The outer tube is formed of a plurality of
layers of porous material to thereby allow air released from the
vent seal zone to pass out of the bag through each of the plurality
of layers of porous material.
[0013] Another embodiment of a multiwall vented bag is provided
which includes an inner tube formed of a plastic material and
having an open-end, a closed end positioned opposite the open end,
an inner tube body extending between the open end and the closed
end, and at least one vent opening formed in the inner tube body.
The bag also includes a strip of material adhering to a preselected
region of the inner tube body and positioned to lie adjacent the at
least one vent opening of the inner tube body, e.g., underlying or
overlying the preselected region of the inner tube body. The strip
extends a preselected longitudinal extent of the inner tube body
and includes at least one vent opening formed therein to allow air
to pass from within the inner tube body, through both of the at
least one vent opening of the inner tube body, and the at least one
vent opening of the strip. The combination of the strip and the
preselected region of the inner tube body define a vent seal zone.
The bag further includes an outer tube positioned to substantially
surround outer surfaces of the inner tube. The outer tube has a
closed end region positioned closely adjacent the closed end of the
inner tube, an open end region positioned closely adjacent the open
end of the inner tube, positioned initially in an open position,
and adapted to receive filling material therethrough, and an outer
tube body extending between the open end region and the closed end
region and overlying the inner tube body and the strip. The outer
tube is formed of a porous material to thereby allow air released
from the vent seal zone to pass out of the bag through the porous
material of the outer tube.
[0014] The present invention also advantageously provides an end
product packaging bag according to an embodiment thereof and
includes a tube formed of at least one ply of plastic material and
having an open-end, a closed end positioned opposite the open end,
a tube body extending between the open end and the closed end, and
at least one vent opening, e.g., preferably a plurality of vent
openings, formed in the tube body. The tube is adapted to be sealed
to closure at its opposite ends. The bag also includes a plastic
strip positioned adjacent and attached to a preselected region of
the tube body including the at least one vent opening of the tube.
The plastic strip also includes at least one vent opening, e.g.,
also preferably a plurality of vent openings, and is positioned to
allow air to pass from within the inner tube body, through both the
at least one vent opening of the tube body and the at least one
vent opening of the plastic strip. The combination of the plastic
strip and the preselected region of the tube body define a vent
seal zone positioned to permit air release after the bag has been
filled with filler material and the open end of the bag has been
sealed. The vent seal zone also can include a channel space
positioned between a surface of the plastic strip and a surface of
the tube body. The channel space allows air to flow therethrough
and extends between the at least one vent opening of the tube body
and the at least one vent opening of the plastic strip so that the
at least one vent opening of the tube and the at least one vent
opening of the strip are not aligned and thereby form a tortuous
path to significantly reduce the risk of insect infestation and to
significantly reduce product sifting when product is positioned in
the bag.
[0015] The present invention still also advantageously provides an
apparatus for forming a vented bag. The apparatus includes a supply
of a tube of at least one ply of plastic material, at least a pair
of spaced-apart rollers each positioned to receive the tube, a
plate member positioned in the tube between the at least a pair of
space-apart rollers, and a perforator roll rotatably positioned
adjacent a first outer surface of the plate member so that the
plate member operates as a stop for the perforator roll to prevent
perforation of a second opposing outer surface of the tube and yet
allowing perforation of the first outer surface of the tube to form
a plurality of spaced apart vent openings in the first outer
surface of the tube when the perforator roll rotates adjacent the
first outer surface of the tube. The tube of at least one ply of
plastic material can extend in a substantially horizontal
orientation between the at least one pair of spaced-apart rollers
during travel in a preselected manufacturing direction, and the
perforator roll can overlie the plate member between the at least
one pair of spaced-apart rollers and overlie and contact a
substantially horizontal extending first outer surface of the tube
to form the plurality of spaced-apart vent openings therein. The
plate member is positioned to be suspended within the tube between
the at least one pair of spaced-apart rollers to thereby define a
floating plate. The floating plate travels within the tube between
the at least one pair of spaced-apart rollers in a suspended
position when the tube is being perforated with the perforator roll
and when the tube travels between the at least one pair of
spaced-apart rollers.
[0016] The apparatus can also include the perforator roll being a
first perforator roll, and the apparatus can further have a
separate supply of plastic strip of material, a second perforator
roll rotatably positioned to contact the plastic strip to form a
plurality of spaced-apart vent openings in the plastic strip, and
an adhering device positioned adjacent the plastic strip and the
tube in a preselected region to adhere the plastic strip material
to the tube to thereby form a vented seal zone having a channel
space formed between surfaces of the plastic strip and the tube so
that the combination of the plurality of vent openings in the tube
and the plurality of vent openings in the plastic strip are
positioned to not align so as to create a tortuous path
therebetween. The at least one ply of plastic material of the tube
can be formed of a continuous seamless, tubular, plastic film. The
tube can define an inner tube, and the apparatus can further have a
supply of porous material and an attaching device positioned to
attach the inner tube to inner surfaces of an outer tube formed of
the porous material to substantially surround the inner tube. A
separator can then separate a plurality of preselected portions of
the attached inner and outer tubes. The preselected portions can be
shaped, formed, and closed on at least one end of the separated
plurality of preselected portions to thereby define a plurality of
separate multiwall bags.
[0017] The present invention also includes methods of forming and
using a bag. For example, according to an embodiment of the present
invention, a method of forming a vented bag includes perforating a
tube of at least one ply of plastic material to form a plurality of
spaced apart vent openings in the tube, perforating a separate
plastic strip of material to form a plurality of spaced apart vent
openings in the plastic strip, and adhering the plastic strip
adjacent the tube in a preselected region to thereby form a vented
seal zone having a channel space formed between surfaces of the
plastic strip and the tube so that the combination of the plurality
of vent openings in the tube and the plurality of vent openings in
the plastic strip are positioned to not align so as to create a
tortuous path to significantly reduce product sifting and insect
infestation when product is positioned within the tube and so that
air within the tube travels through both of the plurality of vent
openings in the tube and the plurality of vent openings in the
plastic strip.
[0018] Another method of forming a vented bag includes positioning
a plate member within a tube of at least one ply of plastic
material and rotatingly perforating the tube with a perforator roll
positioned adjacent a first outer surface of the plate member so
that the plate member operates as a stop for the perforator roll to
prevent perforation of a second opposing outer surface of the tube
and yet allowing perforation of the first outer surface of the tube
to form a plurality of spaced apart vent openings in the first
outer surface of the tube. The method can also include perforating
a separate plastic strip of material to form a plurality of spaced
apart vent openings in the plastic strip and adhering the plastic
strip adjacent the tube in a preselected region to thereby form a
vented seal zone having a channel space formed between surfaces of
the plastic strip and the tube so that the combination of the
plurality of vent openings in the tube and the plurality of vent
openings in the plastic strip are positioned to not align so as to
create a tortuous path to reduce product sifting and insect
infestation when product is positioned within the tube and so that
air within the tube travels through both of the plurality of vent
openings in the tube and the plurality of vent openings in the
plastic strip.
[0019] Another example of an embodiment of a method of using a
multiwall bag having a vent seal zone associated therewith includes
filling first and second multiwall bags with filler material. Each
of the first and second multiwall bags have an inner plastic tube,
a vent seal zone formed by a plastic strip attached to a
preselected region of the inner plastic tube, and an outer tube
formed of a plurality of layers of porous material attached to and
substantially surrounding the inner tube. The inner plastic tube
has a plurality of spaced-apart vent openings and the plastic strip
includes a plurality of spaced-apart vent openings not aligned with
the plurality of space-apart vent openings of the inner plastic
tube so as to create a tortuous path therebetween. The vent seal
zone also includes a channel space positioned between a surface of
the plastic strip and a surface of the inner tube body. The method
also includes closing each of an open end of the first and second
multiwall bags after filler material is filled therein and stacking
the second multiwall bag to overlie and contact the first multiwall
bag so that pressure from weight of the second multiwall bag
increases the air flow from the inner tube of the first multiwall
bag, through both the plurality of vent openings in the inner tube
and the plurality of openings in the plastic strip, and through the
porous material of the outer tube to atmosphere.
[0020] Yet another example of a method of using a bag having a vent
seal zone associated therewith according to an embodiment of the
present invention includes filling a bag with filler material. The
bag has a plastic tube which includes a closed end, an open end
through which filler material flows during filling, and a tube body
extending between the open end and the open end. The bag also has a
vent seal zone defined by a plastic strip attached to a preselected
region of the plastic tube. The plastic tube has a plurality of
spaced-apart vent openings and the plastic strip includes a
plurality of spaced-apart vent openings. The vent seal zone also
includes a channel space positioned between a surface of the
plastic strip and a surface of the tube body. The method also
includes heat sealing the open end of the tube body and an upper
end of the channel space positioned adjacent the open end of the
tube body after filler material is filled therein to a selected
level to thereby seal the open end of the tube body and the upper
end of the channel space. The method can also include compressing
the bag so that trapped gas or air flows from within the tube body,
through the innermost plurality of spaced apart vent openings of
the vent seal zone, through the channel space, along the tortuous
path, through the outermost plurality of spaced apart vent openings
of the vent seal zone.
[0021] A multiwall vented bag having a vent seal zone for packaging
end products according to an embodiment of the present invention
can be used for any type of product, but preferably product types
that allow stacking to take advantage of the performance
characteristics of a multiwall bag. Such product uses include bags
for various food items including dairy products, powdered products,
pet food products, rice or pasta products, and other uses as will
be understood by one skilled in the art and are to be considered
within the scope of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] So that the manner in which the features and advantages of
the invention, as well as others which will become apparent, may be
understood in more detail, more particular description of the
invention briefly summarized above may be had by reference to the
embodiments thereof which are illustrated in the appended drawings,
which form a part of this specification. It is to be noted,
however, that the drawings illustrate only various embodiments of
the invention and are therefore not to be considered limiting of
the invention's scope as it may include other effective embodiments
as well.
[0023] FIG. 1 is a perspective view of a multiwall vented bag
according to an embodiment of the present invention;
[0024] FIG. 2 is perspective view of a multiwall vented bag having
portions thereof broken away for clarity according to an embodiment
of the present invention;
[0025] FIG. 3 is an enlarged fragmentary sectional view of a
multiwall vented bag taken along line 3-3 of FIG. 2 according to an
embodiment of the present invention;
[0026] FIG. 4 is an enlarged fragmentary perspective view of a
multiwall vented bag showing air flow according to an embodiment of
the present invention;
[0027] FIG. 5 is an enlarged fragmentary perspective view of a
multiwall vented bag showing reduction in insect infestation
according to an embodiment of the present invention;
[0028] FIG. 6 is a perspective view of a bag forming apparatus to
form a multiwall vented bag according to an embodiment of the
present invention;
[0029] FIG. 7 is a perspective view of the outer tube of a
multiwall vented bag having portions thereof broken away for
clarity and showing paper plies of an outer tube slit and in a
stepped form according to an embodiment of the present
invention;
[0030] FIG. 8 is a fragmentary perspective view of a closed end
region of a multiwall vented bag in the process of being heat
sealed according to an embodiment of the present invention;
[0031] FIG. 9 is a fragmentary perspective view of a closed end
region of a multiwall vented bag having a satchel bottom according
to an embodiment of the present invention;
[0032] FIG. 10 is a fragmentary perspective view of an open end
region of a multiwall vented bag showing an inner tube connection
to an outer tube at the open end region according to an embodiment
of the present invention;
[0033] FIG. 11 is a perspective view of filler material filling a
multiwall vented bag according to an embodiment of the present
invention;
[0034] FIG. 12 is a perspective view of a multiwall vented bag
showing a heat seal being formed on an open end of an inner tube
thereof according to an embodiment of the present invention;
[0035] FIG. 13 is a perspective view of a multiwall vented bag
having filler material therein and showing an inner tube forming a
pouch being separated from an outer tube body during closing of an
open end region thereof according to an embodiment of the present
invention;
[0036] FIG. 14 is a perspective view of a pinch top closure of an
open end region of an outer tube of a multiwall vented bag
according to an embodiment of the present invention;
[0037] FIG. 15 is an elevational view of a stack of multiwall
vented bags after closure and when air is being released therefrom
according to an embodiment of the present invention;
[0038] FIG. 16 is an elevational view of a stack of multiwall
vented bags after air is initially released therefrom according to
an embodiment of the present invention; and
[0039] FIG. 17 is a perspective view of a multiwall vented bag
having an inner tube pouch thereof being readily removed from an
outer tube body according to an embodiment of the present
invention.
DETAILED DESCRIPTION
[0040] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings, which
illustrate embodiments of the invention. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the illustrated embodiments set forth
herein. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the invention to those skilled in the art. Like numbers
refer to like elements throughout. Prime notation, if used,
indicates similar elements in alternative embodiments.
[0041] As illustrated in FIGS. 1-17, embodiments of the present
invention advantageously provide a multiwall bag 20, e.g., a
plurality of overlying layers or plies of material. The bag
includes an inner tube 22 formed of a plastic material, e.g., such
as supplied from a roll of plastic tube material 27 (see FIGS. 1-2
and 6). In a preferred embodiment of the bag 20, the plastic
material includes a seamless, tubular plastic film. "Seamless" is
used herein as lacking or being devoid of at least any longitudinal
seam, and more preferably no lateral seams other than end closures
as well, that is, manufactured as a continuous tubular plastic film
(see FIG. 6) and not a rectangular sheet which is heat or otherwise
sealed along a longitudinal axis between ends thereof or a
horizontal axis transverse to ends thereof. The inner tube 22 has
an open-end 23, a closed end 24 positioned opposite the open end
23, and an inner tube body 25 extending between the open end 23 and
the closed end 24 (see FIGS. 1 and 17). The inner tube 22 also
includes at least one inner vent opening 26, and more preferably a
plurality of vent opening 26, formed in the inner tube body 25 (see
FIG. 1).
[0042] As perhaps best shown in FIG. 2-6, the bag 20 also includes
a plastic strip 31 overlying and adhering to a preselected region
32 of the inner tube body 25 and positioned to overlie the at least
one inner vent opening 26. As shown in FIGS. 1-2, and 6, in an
embodiment of the bag 20, the plastic strip 31 extends
substantially the entire longitudinal extent of the tube body 25.
Other embodiments of the positioning of the plastic strip 31, e.g.,
lateral, transverse, arcuate, shaped, or pattern, adjacent the tube
body 25 can be used as well according to the present invention.
Although the positioning of the plastic strip 31 has some distinct
advantages with respect to ease of manufacturing and enhance
performance characteristics of the bag 20, e.g., quicker and more
even venting of air or gas from the inner tube 22, this feature is
not of necessity in order to still comply with the scope and spirit
of the invention. As shown in FIG. 4, the plastic strip 31 includes
at least one outer vent opening 36, and preferably a plurality of
vent openings 36, to allow air to pass from within the inner tube
body 25, through the at least one inner vent opening 26, and
through the at least one outer vent opening 36. The combination of
the plastic strip 31 and the preselected region 32 of the inner
tube body 25 define a vent seal zone 40. Note, the term "air"
refers to any gaseous substance as used herein. Also, although the
plastic strip 31 is illustrated and described by way of example as
positioned to overlie an outer surface of the inner tube body 25,
the invention also contemplates positioning the plastic strip 31
along an inner surface of the tube body 25 as well.
[0043] In an embodiment of a bag 20, as shown in FIGS. 1 and 2, the
at least one inner vent opening 26 includes a plurality of vent
openings 26 positioned in a space-apart relation such as along the
longitudinal extent of the tube body. The plurality of vent
openings each can be one opening, e.g., a pinhole, as shown, group
or cluster of openings spaced-apart, or a preselected pattern,
e.g., rows and columns, clusters, stars arrangements, and
rectangular arrangements, if desired. Also, the at least one outer
vent opening 36 can include a plurality of outer vent openings 36
positioned in a spaced-apart relation along the longitudinal extend
of the plastic strip as well. The plurality of outer vent openings
36 are positioned spaced apart from and do not align with, e.g.,
directly overlie, the plurality of inner vent openings 26. Instead,
a plurality of individual holes such as the pin holes shown,
openings, slits or patterns, groups, or clusters of vent openings
26 are positioned at different locations along the longitudinal
extent of the inner tube body than the locations of individual
holes such as the pinholes shown, openings, slits or patterns,
groups, or clusters of vent openings 36 formed in the overlying
plastic strip 31.
[0044] As shown in FIGS. 1-2 and 7, the bag 20 includes an outer
tube 52 positioned to substantially surround outer surfaces of the
inner tube 22. The outer tube 52 has a closed end region 54 and an
open end region 53 being initially in an open position and adapted
to receive filling material therethrough. The outer tube 52 also
includes an outer tube body 55 extending between the open end
region 53 and the closed end region 54 and overlying the plastic
strip 31. As shown in FIGS. 2-3, 6-7, 9, and 15-16, the outer tube
52 is formed of a plurality of layers of a porous material 57, 58,
59, e.g., paper or paper ply such as in a range of two to six
layers, to thereby allow air released from the vent seal zone 40 to
exit from, travel from, flow, or pass out of the bag 20 through the
porous material 57, 58, 59. In an embodiment of a bag 20,
overlapping edges of the multiple plies 57, 58, 59 of the nonporous
material are adhesively bonded to form the tube 52. All of this
forming, for example, can be done by a tuber or tube former as
understood by those skilled in the art.
[0045] In an embodiment of a bag 20, as shown in FIGS. 1 and 6, the
plastic material 27 forming the inner tube 22 does not include a
longitudinal seam used to form a sheet of plastic material into a
tube. In this embodiment, the plastic material 27 is formed into a
continuous, unseamed or seamless, tubular film of plastic, which
forms a continuous plastic tube 22. In an alternative embodiment,
however, forming the inner tube 22 by heat or otherwise sealing the
longitudinal edges of a flat sheet or web, may be accomplished in
the bag making process to create a tube 22, but with a longitudinal
seam. As shown in FIGS. 3-6, the strip 31 is formed of a plastic
material 37 overlays a preselected region 32 of the inner tube body
25 and is positioned to overlie the at least one inner vent opening
26. The vent seal zone 40 includes a channel space 42 positioned
between a surface, e.g., an inner surface 33, of the plastic strip
31 and a surface, e.g., an outer surface 28, of the inner tube body
25. For ease of manufacturing and to enhance air flow, the channel
space 42 can advantageously be unobstructed, but having baffles or
other obstructions which allow air or gas to flow between a vent
opening in the tube body and a vent opening in the strip can also
be used as well according to the present invention and still be a
channel space as will be understood by those skilled in the art. If
the channel space 42 is unobstructed, then stacking,
compressibility, and formation of the position or location of vent
opening can be enhanced or made easier as well.
[0046] The channel space 42 of the vent seal zone 40 is
substantially elongate and extends substantially the length of the
inner tube body 25 between the open end 23 and the closed end 24
thereof. The plastic strip 31 includes at least one perforation,
slit, hole, or piercing forming the at least one outer vent opening
36, e.g., formed by a perforating roll 38, to allow air to either
enter or exit the channel space 42 created between the inner tube
22 and the plastic strip 31, depending on whether the strip 31 is
configured on the inside or outside of the inner tube. The inner
tube 22 also includes at least one perforation, slit, hole, or
piercing forming the at least one inner vent opening 26, e.g.,
formed by a perforating roll 21 and a floating plate or roll stop
member 29, to allow air to either enter or exit the channel space
42 created between the inner tube 22 and the plastic strip 31. The
floating plate or roll member 29 can advantageously be positioned
inside the tube 22, e.g., between respective inner surface of faces
or walls of the continuous tube material prior to perforation and
float in a trapped or enclosed region as the perforating roll 21
rotates along an outer surface of the tube 22. The vent openings or
holes 26, 36, for example, advantageously can be as small as the
size of pinholes. Advantageously, the channel space 42 extends
between at least one inner vent opening 26 and at least one outer
vent opening 36 so that the at least one inner vent opening 26 and
the at least one outer vent opening 36 are not aligned, e.g., do
not directly overlie or underlie, and thereby form a tortuous path.
"Tortuous path" is used herein as a path other than a path parallel
to an axis directly perpendicular to the longitudinal plain of the
plastic material strip 31. This path helps to significantly reduce
product sifting and insect infestation. Also, as illustrated, have
both lateral and longitudinal spacing between vent openings 36 in
the plastic strip 31 and vent openings 26 in the inner tube
advantageously makes even further reduces the risk of product
sifting and insect infestation and yet still allows air or gas to
be readily released from the inner tube. Additionally, the
preselected spacing between individual openings, e.g., holes as
shown or clusters holes, can enhance ease of manufacturing and
enhances air flow from the channel without greatly increasing the
risk of product sifting or insect infestation. For example,
selecting a different number or a spacing between individual
openings, e.g., individual holes 26, 36 or groups of holes, such as
one hole every three inches, six inches, or eight inches,
advantageously can be used depending on the desired air flow from
the inner tube body in relation to the length or size of the bag
20.
[0047] In an embodiment, as shown by FIG. 4, the bag 20 can further
include a pair of spaced-apart longitudinal adhesive regions 45
positioned between outer surfaces of the inner tube body 25 and a
pair of elongate inner surface regions of the plastic strip 31 so
that the channel space 42 extends between the pair of spaced-apart
longitudinal adhesive regions 45. Using the adhesive regions 45
enhances ease of manufacturing and forming the internal bag, but
other adhering techniques or processes such as sealing, bonding, or
molding as understood by those skilled in the art can be used as
well according to the present invention. The channel space 42 thus
allows air to flow therethrough. The channel space 42 is formed by
the combination of the inner tube 22 and plastic strip 31. In this
way, as shown in FIGS. 3 and 4, and in the preferred configuration
of the channel space 42, air flows from within the inner tube body
25, and through the at least one inner vent opening 26, a plurality
of spaced-apart inner vent openings 26 in the preferred embodiment.
The air then flows through the channel space 42 extending between
the pair of spaced-apart longitudinal adhesive regions 45, along
the tortuous path, and through the at least one outer vent opening
36, a plurality of spaced-apart outer vent openings 36 in the
preferred embodiment (see, e.g., FIG. 3). The air then flows into
an innermost layer 57 of the plurality of layers 57, 58, 59 of
porous material, and through at least one overlying layer, e.g.,
58, 59, of the plurality of layers 57, 58, 59 of porous material.
Note that although the preferred embodiment includes a plurality of
layers of porous material 57, only one layer is required to comply
with the spirit of the present invention. In an embodiment of the
bag 20, two longitudinal spaced beads of adhesive 46 are used to
adhesively secure the plastic strip 31 to the selected region 32 of
the inner tube body 25. The seal along the plastic strip 31 can be
heat responsive beads of adhesive 46 or other non-heat responsive
seals as understood by those skilled in the art.
[0048] An embodiment of the present invention advantageously
provides a multiwall bag 20 having an outer tube 52 which allows
air released from the channel space 42 in the vented seal zone 40
to pass out of the bag 20 via the porosity of the outer tube
material. In an embodiment, the at least one innermost layer 57 of
porous material of the outer tube 52 is perforated. The
perforations or auxiliary perforations 49, e.g., in addition to the
more natural pores of the porous material, aids the expulsion of
trapped air gathered between the inner tube 22 and the outer tube
52. These perforations in the innermost layer 57, for example, can
be only on one front or back side of the bag 20 and also can be
positioned in the closed end region 54, the open end region 53, or
both. By positioning these perforations or slits in the closed end
region 54, for example, manufacturing and forming the bag 20 can be
enhanced such as when forming a satchel bottom 81 as understood by
those skilled in the art and still enhance air passing from the
inner tube 22 through the outer tube 52.
[0049] In an embodiment of the bag 20, as shown by FIGS. 8-9, the
closed end 24 of the inner tube 22 is heat-sealed during the bag
forming, manufacturing, or making process. The heat seal seals or
closes both the closed end 24 of the inner tube 22 and the lower
end of the channel space 42 adjacent the closed end 24. The
multiwall bag 20 can advantageously have the closed end 24 of the
inner tube 22 detachably adhered to the closed end region 54 of an
outer tube 52 so that the inner tube 22 remains adhered to the
outer tube 52 during filling of the bag 20 with filling material.
The closed end 24, for example, can be adhered or bonded using
individual beads 64 of adhesive material, preferably using a
plurality of beads 64 of adhesive material or similar methodology,
on one-half or one side inner surface, e.g., front or back, of the
outer tube 52, or one side of the outer surface 28 of the inner
tube 22. This advantageously allows the inner tube 22 to be readily
detach or separated from to the inner ply 57 of the outer tube 52
without damage to the inner tube 22, e.g., no tearing, ripping, or
puncturing, when the inner tube 22 is filled with product or filler
material (see, e.g., FIG. 17). Although the bonding may be
accomplished on both sides of an inner ply of the outer tube 22,
bonding only on one side is preferred as it allows for ease of
folding the inner tube 22 with the outer tube 52 and provides the
user of the bag 20 with the ability to selectively remove the inner
tube 22 from the outer tube 52 when the inner tube 22 has filling
material positioned therein.
[0050] Also, in an embodiment of a multiwall vented bag 20, as
shown in FIG. 10, the inner tube 22 is correspondingly bonded at
its circumference adjacent the open end 23 in order to best secure
the inner tube 22 inside the outer tube 52. This is accomplished by
individual beads 74 of adhesive, though other methodologies are of
course possible, including the use of an adhesive strip. This
adhesive attachment or beads along the open end region of the outer
tube 52 allows the inner tube 22 to be readily sealed and separated
from inner surfaces of the outer tube 52 so that the inner tube 22
having filling material therein then becomes an inner pouch or bag
having a seal at the upper end thereof of both the inner tube 22
and the channel space 42.
[0051] As shown by FIGS. 7 and 9, an embodiment of a multiwall
vented bag 20 also advantageously provides an outer tube 52, which
includes a front region and a back region opposite the front region
out of the outer tube body 55. As understood by those skilled in
the art, the closed end region 54 of the outer tube 22 can
advantageously include a satchel bottom 81. In an embodiment of the
bag 20, the outer tube 52 can be cut during the bag manufacturing
process using perforator knives as understood by those skilled in
the art that allow a multiwall paper satchel bottom 81 to be folded
onto the inner tube 22 to retain the closed end 24 of the inner
tube 22. The satchel bottom 81 is basically formed by slitting,
cutting, or perforating the paper or porous material. In an
embodiment of a bag 20, this can be accomplished along a single
longitudinal axis on a selected portion of the tube 52. For
example, a series of slits 49 can be cut through all plies of the
outer tube 52. Two parallel slits 49 are made adjacent the closed
end 54 and on a first side of the outer tube 52 and two parallel
slits 49 are correspondingly made adjacent the closed end 54 and on
a second side thereof. The depth and spacing can be accomplished to
optimize the lateral distances between the slits 49 on sequential
plies as understood by those skilled in the art. As shown in FIGS.
6-7, in an embodiment of a bag 20, the outer tube 52 can have a
stepped arrangement on the layers 57, 58, 59 of porous material on
a selected side, e.g., front or back region, of the closed-end
region 54 and a correspondingly yet opposite arrangement on the
open end region 53. Alternative embodiments, however, can also
provide the customer with a flush cut top, patch bottom, or pinch
bottom. In the preferred embodiment, the porous material is paper
ply stepped longitudinally and oppositely on the front and back
sides in order to provide an easier folding capability on the
closed end region 54 and a smoother contour of an upper seal with
the open end region 53, especially when an embodiment calls for the
open end region 53 to include a pinch step closure pattern. In an
embodiment of a bag 20 as shown in FIGS. 8, 12-14, the bag further
can include a pre-applied hot melt 92 or other adhesive methodology
applied to the open end region 53 of the outer tube 52 that can be
reactivated by the user after the bag 20 has been filled with
product (see, e.g., FIG. 14). Also as part of the open end sealing
process, in an embodiment, the heat sealing of the open end 23 of
the inner tube 22 can advantageously correspondingly seal the
channel space 42 adjacent the open end 23 of the inner tube 22.
Although only heat sealing methodology has been elaborated on
regarding sealing the open and closed ends and ends of the channel
space, other sealing methodologies, as desired, can be used and
still comply with the spirit of the various embodiments of the
present invention.
[0052] As illustrated in FIGS. 3-6, 8, 10, and 17, an embodiment of
the present invention advantageously also provides an end product
packaging bag, e.g., formed by the inner tube 22 or pouch. The bag
includes a tube 22 formed of at least one ply of plastic or
non-porous material. The plastic material advantageously can
include a seamless, tubular plastic film 27. The tube 22 has an
open-end 23, a closed end 24 positioned opposite the open end 23, a
tube body 25 extending between the open end 23 and the closed end
24, and at least one vent opening 26 formed in the tube body 25. As
shown in FIG. 6, the bag also includes a vent seal zone 40, e.g., a
vented assembly as will be understood by those skilled in the art.
The vent seal zone 40 includes a plastic or otherwise non-porous
material strip 31 overlying and adhering to a preselected region 32
of the tube body 22. The strip 31 is positioned to overlie, or
underlie in other embodiments, the at least one vent opening 26 of
the tube 22. The plastic or otherwise non-porous material strip 31
also includes at least one vent opening 36. This combination of the
plastic or otherwise non-porous material strip 31 and the
preselected region 32 of the tube body 25 defines the vent seal
zone 40 as illustrated and described herein.
[0053] As shown in FIG. 4, the vent seal zone 40 includes a channel
space 42 positioned between an inner surface 33 of the plastic or
otherwise non-porous material strip 31 and a surface of the tube
body 25. This channel space 42 is preferably unobstructed in any
significant manner so that the channel space 42 readily also allows
air to flow therethrough and remains substantially flat during
stacking of bags 20 or pouches when filled with filler material or
product. The channel space 42 extends between the at least one vent
opening 26 of the tube 22 and the at least one vent opening 36 of
the plastic or otherwise non-porous material strip 31 so that the
at least one vent openings 26 of the tube 22 and the at least one
vent opening 36 of the strip 31 are not aligned and thereby form a
tortuous path to reduce the risk of insect infestation and to
reduce product sifting when product is positioned in the bag. In an
embodiment of the bag, the channel space 42 of the vent seal zone
40 is substantially elongate and extends substantially the length
of the inner tube body 25 between the open end 23 and the closed
end 24 thereof. The plastic strip 31 includes at least one
perforation, slit, hole, or piercing forming a vent opening 36 to
allow air to either enter or exit the channel space 42 created
between the tube 22 and the plastic strip 31, depending on whether
the strip is configured on the inside 29 or outside 28 of the tube
22. The tube 22 also includes at least one perforation, slit, hole,
or piercing forming a vent opening 26 to allow air to either enter
or exit the channel space 42 created between the tube 22 and the
plastic strip 31. The vent openings or holes, 26, 36 can be as
small as the size of pinholes, for example. The at least one vent
opening 36 of the plastic or otherwise non-porous material strip 31
and the tube 22 advantageously can be provided by a plurality of
spaced-apart vent openings 26, 36 positioned in a preselected
spaced relationship along the longitudinal extent of the tube 22
and the strip 31. The plurality of vent openings 36 of the strip 31
are positioned spaced apart from and do not directly overlie the
plurality of vent openings 26 of the tube 22 as illustrated and
described herein.
[0054] As shown in FIGS. 4, 6 and 8, the plastic or otherwise
nonporous material forming the tube 22 advantageously does not
include a longitudinal seam used to form a sheet of plastic or
non-porous material into a tube 22. In this embodiment of a bag,
the plastic or non-porous material 27 is formed from a continuous,
unseamed or seamless, tubular, film of plastic, which forms a
continuous plastic tube body 25. In an alternative embodiment, a
tube 22 having a longitudinal seam may be used. The tube 22 may be
formed by heat or otherwise sealing the longitudinal edges of a
flat sheet or web to create a tube, albeit with a longitudinal
seam.
[0055] As shown in an embodiment of a bag in FIGS. 8 and 17, shown
inside an external bag or outer tube, the closed end 24 of the tube
is heat-sealed during the bag making process (see, e.g., FIGS.
8-9). The heat seal 28 seals both the closed end 24 of the tube 22
and the end of the channel space 42 adjacent the closed end 24. For
example, to enhance the ease of manufacturing or forming a bag 20,
the closed end 24 of the tube 22 and the closed end region 54 of
the outer tube 52 can collectively or in combination pass through a
radiant set of heat bars as understood by those skilled in the art
to heat the combination of the closed end 24 and at least portions
of the closed end region 54 from outside of the outer tube 52 so
that the heat also softens or melts the plastic material of the
tube 22 and the plastic strip 31. As will be understood by those
skilled in the art, however, other sealing techniques or methods
can be used as well according to the present invention for sealing
the ends of the tube body and for attaching the plastic strip to
the tube body such as radio frequency, microwave, sonic, infrared,
or other techniques. The closed end 24 and the at least portions of
the closed end region 54 can then pass through a nip roller such as
illustrated to enhance or form the heat seal 28 under nip or
contact pressure. Other examples, as understood by those skilled in
the art, can be used as well according to the present invention. An
embodiment of the present invention advantageously allows the end
product packaging bag ("internal bag") to be utilized within an
external bag formed of a porous material or within a bag formed of
nonporous material preferably providing that it includes provisions
to allow the release of trapped air. Various methodologies used
include bonding the closed end 24 of the internal bag to the
external bag, using a plurality of beads of adhesive 64 or similar
methodology, on only one-half or one side of the tube 22. This
provides for the internal bag to be detachably connected to the
innermost ply of the external bag as described above herein.
[0056] Once the end product packaging bag has been filled with the
material, in the preferred embodiment, the user can heat seal the
open end 23 closed (see FIG. 12). This open end 23 sealing can be
performed somewhat like the description above with respect to the
closed end 24 by also using heat sealing such as a set of radiant
heat bars and a nip roller or set of rollers, as shown and as
understood by those skilled in the art, passing over outer surfaces
of the outer tube 52. The heat sealing of the open end 23 of the
bag correspondingly seals the channel space 42 adjacent the open
end 23 of the tube 22. Although only heat sealing methodology has
been elaborated on regarding sealing the open and closed ends 23,
24 of the tube 22, and the open and closed ends of the channel
space 42, other sealing methodologies, as desired, can be used and
still comply with the spirit of the various embodiments of the
present invention as will be understood by those skilled in the
art. Note also, it is a significant advantage of an embodiment of
the present invention to form the end product packaging bag through
use of a continuous unseamed plastic film rather than by forming
the plastic material tube 22 by heat or otherwise sealing
longitudinal edges of a flat sheet or web to form a tube 22 with a
longitudinal seam. It is a further advantage to form or use a
continuous unseamed plastic film rather than creating a tube 22
having a longitudinal seam formed by overlapping longitudinal
margins of the flat sheet or web.
[0057] As perhaps best shown in FIG. 6, the present invention still
also advantageously provides an apparatus for forming a vented bag
20. The apparatus includes a supply 27 of a tube 22 of at least one
ply of plastic material, at least a pair of spaced-apart rollers,
such as a pair of spaced-apart pair of rollers 62, 63 as shown.
Each of the at least a pair of spaced-apart rollers 62, 63 is
positioned to receive the tube 22, a plate member 29, such as
formed of a metal material, is positioned in the tube 22 between
the at least a pair of space-apart rollers 62, 63, and a perforator
roll 21 is positioned adjacent a first outer surface of the plate
member 29 so that the plate member 29 operates as a stop for the
perforator roll 21 to prevent perforation of a second opposing
outer surface of the tube 22 and yet allowing perforation of the
first outer surface of the tube 22 to form a plurality of spaced
apart vent openings in the first outer surface of the tube 22. The
perforator roll 21 can have one or more perforating pins 19, or
other perforating member as understood by those skilled in the art,
associated with the roll 21, such as connected to an outer surface
of the roll, when the perforator roll 21 rotates, e.g., by a drive
as understood by those skilled in the art, and contacts the tube
22. The tube 22 of at least one ply of plastic material can extend
in a substantially horizontal orientation between the at least one
pair of spaced-apart rollers during travel in a preselected
manufacturing direction as illustrated in FIG. 6, and the
perforator roll 21 can overlie the plate member 29 between the at
least one pair of spaced-apart rollers 62, 63 and overlie a
substantially horizontal extending first outer surface of the tube
22 to form the plurality of spaced-apart vent openings 26 therein
when rotating and contacting the tube 22. The plate member 29 is
positioned to be suspended within the tube 22 between the at least
one pair of spaced-apart rollers 62, 63 to thereby define a
floating plate, and the floating plate 29 can travel or move within
the tube 22 between the at least one pair of spaced-apart rollers
26, 28 in a suspended position when the tube 22 is being perforated
with the perforator roll 21 and when the tube 22 travels between
the at least one pair of spaced-apart rollers 62, 63.
[0058] The apparatus can also include the perforator roll 21 being
a first perforator roll, and the apparatus further having a
separate supply 37 of plastic strip 31 of material, a second
perforator roll 38 having a perforating pin 39, or other
perforating member as understood by those skilled in the art,
positioned to contact the plastic strip 31 to form a plurality of
spaced apart vent openings in the plastic strip 31, and an adhering
device 41, such as an adhesive applicator mounted on a frame member
as shown, a sealer, other adherer, and/or in combination with one
or more press rollers 66, positioned adjacent the plastic strip 31
and the tube 22 in a preselected region to adhere the plastic strip
material to the tube 22 to thereby form a vented seal zone having a
channel space formed between surfaces of the plastic strip and the
tube 22 so that the combination of the plurality of vent openings
26 in the tube 22 and the plurality of vent openings 36 in the
plastic strip 31 are positioned to not align so as to create a
tortuous path to reduce product sifting and insect infestation when
product is positioned within the tube 22 and so that air within the
tube travels through both of the plurality of vent openings in the
tube and the plurality of vent openings in the plastic strip. The
at least one ply of plastic material of the tube 22 can be formed
of a continuous seamless, tubular, plastic film, the tube 22 can
form an inner tube, and the apparatus can further have a supply of
porous material 57, 58, 59 a roll 69 or other conveyor, and an
attaching device 67, 68, such as a laminator, sealer, press,
roller, and/or a combination, positioned to attach the inner tube
22 to inner surfaces of an outer tube 52 formed of the porous
material 57, 58, 59 to substantially surround the inner tube 22
such as during shaping or forming as understood by those skilled in
the art. A separator (such as indicated by the "To Cutter and
Former" block), such as a knife, a cutter, a cutting roll, or other
separator as understood by those skilled in the art, can then be
positioned downstream to selectively separate a plurality of
preselected portions of the attached inner and outer tubes, further
shape or form the bag such as by folding over and sealing outer
tube portions after cutting or separating as understood by the
those skilled in the art, and close at least one end of the
separated plurality of preselected portions to thereby define a
plurality of separate multiwall bags 20.
[0059] As shown in FIGS. 1-17, and perhaps as best illustrated in
FIGS. 6-7 and 12-17, in addition to the multiwall bag 20 having a
vent seal zone 40, the present invention also advantageously
provides methods of forming and using a multiwall vented bag 20, a
vented bag 20, or a bag in general. A method of forming a vented
bag 20, for example, can include perforating a tube 22 of at least
one ply of plastic material to form a plurality of spaced apart
vent openings 26 in the tube 22, perforating a separate plastic
strip 31 of material to form a plurality of spaced apart vent
openings 36 in the plastic strip 31, and adhering the plastic strip
31 adjacent the tube 22 in a preselected region to thereby form a
vented seal zone 40 having a channel space 42 formed between
surfaces of the plastic strip 31 and the tube 22 so that the
combination of the plurality of vent openings 26 in the tube 22 and
the plurality of vent openings 36 in the plastic strip 31 are
positioned to not align so as to create a tortuous path to
significantly reduce product sifting and insect infestation when
product is positioned within the tube 22 and so that air within the
tube 22 travels through both of the plurality of vent openings 26
in the tube 26 and the plurality of vent openings 36 in the plastic
strip 31.
[0060] The method of forming a bag 20 can also include the at least
one ply of plastic material of the tube 22 being a continuous
seamless, tubular, plastic film. Also, the tube 22 can be an inner
tube, and the method can further include attaching the inner tube
22 to inner surfaces of an outer tube 52 formed of a porous
material to substantially surround the inner tube 22. The plastic
strip 31 can extend substantially the entire longitudinal extent of
inner tube 22, and the outer tube 52 can be formed of a plurality
of layers 57, 58, 59 of porous material so that air exiting the
inner tube 22 travels into or enters the porous material of the
outer tube 52 and then exits or passes into atmosphere. The method
can also include heat sealing an end of the tube 22 defining a
closed end of the inner tube and heat sealing the channel space 42
adjacent the closed end 24 of the inner tube 22. The method can
also include heat sealing the open end 23 of the inner tube 22 and
an upper end of the channel space 42 positioned adjacent the open
end 23 of the inner tube 22 after filler material is filled therein
to a selected level to thereby seal the open end 23 of the inner
tube 22 and the upper end of the channel space 42. The method
further can include severing, e.g., using score lines through the
outer tube of the bag (FIG. 13) as understood by those skilled in
the art, or using some other separating technique as understood by
those skilled in the art, the inner tube 22 from the open end 53 of
the outer tube 52 to thereby form a sealed plastic pouch within a
paper outer bag.
[0061] The tube 22 as described above and as illustrated herein can
be an inner tube 22, and the method can further include forming an
outer tube 52 positioned to substantially surround outer surfaces
of the inner tube 22. The outer tube 52 can have a closed end
region 54, an open end region 53 being initially in an open
position and adapted to receive filling material therethrough, and
an outer tube body 55 extending between the open end region 53 and
the closed end region 54 and overlying the plastic strip 31. The
outer tube 52, for example, can be formed by laminating a plurality
of stepped layers 57, 58, 59 of a porous material. The method of
forming a bag 20 still further can include forming selective
regions of adhesive material between inner surfaces of the closed
end region 54 of the outer tube body 55 and outer surfaces of the
inner tube 22 so that the closed end 24 of the inner tube 22 is
detachably adhered to the closed end region 54 of the outer tube
52, so that the inner tube 22 remains adhered to the outer tube 52
until after the bag 20 is filled to a selected level with filling
material, and so that a user of the bag 20 can readily remove the
inner tube 22 from the outer tube 52 without damage to the inner
tube 22 when the inner tube 22 has filling material positioned
therein. The method can also include forming or supplying a plastic
strip 31 of at least one ply of plastic material 37. More
particularly, in an embodiment, the plastic material strip 31 is
formed out of at least one ply of plastic film 37, and is cut at
approximately four inches wide, and has a length approximately
equal to the length of the inner tube body 25 (see FIGS. 1-2 and
6). Significant deviations from this size is possible, however, and
still remain within the spirit of this disclosure. The method can
also include perforating the inner tube 22 and plastic strip 31
with at least one vent opening 26, 36, using a perforator roll 21,
58 or knife stack (see, e.g., FIG. 6) having a perforation pin 19,
39 attached to the roll 21, 58. This forms a plurality of spaced
apart vent openings 26, 36, in both the inner tube 22 and the
plastic strip 31, to allow air to pass from within the inner tube
body 25, through the plurality of spaced apart inner vent openings
26 or 36, and through the plurality of spaced apart outer vent
openings 36 or 26, depending on whether the plastic strip 31 is
configured on the outer surface or the inner surface of the inner
tube 22. In an embodiment, the perforations 26, 36, are made to the
inner tube 22 and plastic strip 31 at temporally separate instances
along a direction of manufacture or travel of material in forming
one or more bags.
[0062] According to an embodiment of the method, as perhaps best
shown in FIG. 9, the method can further include forming a satchel
bottom 81 upon outer tube 52 as understood by those skilled in the
art. The satchel bottom 81, for example, can be cut, formed, and
folded to retain the closed end 24 of the inner tube 22. In an
embodiment, a plurality of parallel slits 49 are cut in the first
and second, e.g., front and back, sides of the outer tube 52. The
depth and spacing are accomplished to optimize the lateral
distances between the slits 49 on sequential plies as understood by
those skilled in the art. In an embodiment, the paper ply or porous
material of the layers 57, 58, 59 of the outer tube 52, as
described above, is stepped longitudinally and oppositely on the
front and back or first and second sides, in order to provide an
easier folding capability on the closed end region 54 and a
smoother contour of a seal of the adhesive material 92 on the open
end region 53, especially when an embodiment calls for the open end
region 53 to include a pinch step closure pattern. Nevertheless, in
the embodiment calling for a satchel bottom 81, a main score line
and a series of smaller score lines are made across all paper or
porous material plies 57, 58, 59, thus allowing the folding of the
outer tube closed end region 54, as understood by those skilled in
the art.
[0063] As shown in FIGS. 11-14, in the current described form, the
multiwall bag 20 can be ready to be filled with a filler material.
The method of forming the bag 20 correspondingly includes the step
of sealing the bag 20 closed upon filling the bag 20 with the
filler material. In this embodiment, the method further includes
sealing the inner tube 22 and sealing the outer tube 52. Although
other methodologies are available, as noted above, the preferred
methodology of sealing the outer tube 52 is accomplished by the use
of the pre-applied hot melt 92 or other adhesive material applied
to the open end region 53 that can be reactivated by the user after
the bag 20 has been filled with product. One of the many
methodologies for reactivating the open end region 53 adhesive, for
example, include use of a hot air blast as understood by those
skilled in the art (see FIG. 14).
[0064] Although other methodologies are available, as noted above,
the preferred methodology of sealing the inner tube 22 is
accomplished by use of a pair of heated bars or rolls, as is
described previously, which are actuated compressibly against
opposing sides or front and back surfaces, of the outer surface of
the inner tube 22 adjacent the open end 23. The inner tube opening
23 can be pressed into a substantially flat form. The bars are
heated to a sufficient temperature to fuse the open end 23 of the
inner tube 22 to itself, thus forming an airtight seal. The
temperatures and pressures required in this embodiment and in
alternative embodiments using different fusion bonding
methodologies are well known by those skilled in the art.
Alternatively, the open end inner tube sealing can be accomplished
using a non-heat responsive method as known by those skilled in the
art. In either case, if not already accomplished, the heat sealing
or other selected methodology of sealing the open end 23 of the
inner tube 22, correspondingly seals the channel space 42 adjacent
the open end 23 of the inner tube 22. In an embodiment of a bag 20,
the inner tube 22 is to be housed independently of the outer tube
52 after filling. In this embodiment, following the heat sealing
and while the heated fusion area is still malleable, a cutter or
separator such as a pair of beveled compression rollers are
compressibly and traversely drawn across the fusion area to sever
the inner tube 22 within the outer tube 52 without severing the
outer tube 52 (see, e.g., FIG. 13). This allows for hygienic
removal of the inner tube at destination (see FIG. 17).
[0065] As illustrated in FIG. 6, as well as other figures, a method
of forming a vented bag 20 is provided which includes positioning a
plate member 29 within a tube 22 of at least one ply of plastic
material 27 and rotatingly perforating the tube 22 with a
perforator roll 21 positioned adjacent a first outer surface of the
plate member 29 so that the plate member 29 operates as a stop for
the perforator roll 21 to prevent perforation of a second opposing
outer surface of the tube 22 and yet allowing perforation of the
first outer surface of the tube to form a plurality of spaced apart
vent openings 26 in the first outer surface of the tube 22. The
method can also include perforating a separate plastic strip 31 of
material 37 to form a plurality of spaced apart vent openings 36 in
the plastic strip 31 and adhering the plastic strip 31 adjacent the
tube 22 in a preselected region to thereby form a vented seal zone
having a channel space formed between surfaces of the plastic strip
and the tube so that the combination of the plurality of vent
openings 26 in the tube 22 and the plurality of vent openings 36 in
the plastic strip 31 are positioned to not align so as to create a
tortuous path to reduce product sifting and insect infestation when
product is positioned within the tube 22 and so that air within the
tube 22 travels through both of the plurality of vent openings 26
in the tube 22 and the plurality of vent openings 36 in the plastic
strip 31.
[0066] The at least one ply of plastic material 27 of the tube 22
preferably is a continuous seamless, tubular, plastic film that is
used to form an inner tube. The method can further include
attaching the inner tube 22 to inner surfaces of an outer tube 52
formed of a porous material, 57, 58, 59, e.g., being transported in
a substantially horizontal plane from a flooring surface, to
substantially surround the inner tube 22. The plastic strip 31
extends substantially the entire longitudinal extent of inner tube
31, and the outer tube 52 has a plurality of layers 57, 58, 59 of
porous material, e.g., paper, so that air exiting the inner 22 tube
travels into the porous material 27 of the outer tube 52 and into
atmosphere therefrom. The tube 22 of the plastic material 27
extends in a substantially horizontal orientation, e.g., this can
include a slight upward slope, e.g., less than 45 degrees from the
substantially horizontal plane of the extent of the porous material
as illustrated or a slight downward slope, between at least one
pair of spaced-apart rollers during travel in a preselected
manufacturing direction. The plate member 29 is positioned in the
tube 22 between the at least one pair of spaced-apart rollers 62
63, and the perforator roll 21 overlies the plate member between
the at least one pair of spaced-apart rollers and overlies a
substantially horizontal extending first outer surface of the tube
to form the plurality of spaced-apart vent openings therein.
[0067] The plate member 29 can be a metal material or other
effective stop material for the perforating pin 19 on the
perforator roll 21. The plate member 29 is positioned to be
suspended within the tube between the at least one pair of
spaced-apart rollers 62, 63 to thereby define a floating plate. The
floating plate 29 travels within the tube 22 between the at least
one pair of spaced-apart rollers 62, 63 in a suspended position
when the tube 22 is being perforated with the perforator roll 21
during travel between the at least one pair of spaced-apart rollers
62, 63. The method can further include heat sealing an end of the
tube defining a closed end of the inner tube and heat sealing the
channel space adjacent the closed end of the inner tube. The method
can still further include heat sealing the open end of the inner
tube and an upper end of the channel space positioned adjacent the
open end of the inner tube after filler material is filled therein
to a selected level to thereby seal the open end of the inner tube
and the upper end of the channel space.
[0068] As discussed above herein, the tube 22 can be or form an
inner tube 22, and the method can also further include forming an
outer tube 52 positioned to substantially surround outer surfaces
of the inner tube. The outer tube 52 has a closed end region, an
open end region being initially in an open position and adapted to
receive filling material therethrough, and an outer tube body
extending between the open end region and the closed end region and
overlying the plastic strip. The outer tube 52 can be formed by
laminating a plurality of stepped layers 57, 58, 59 of a porous
material. The method also can include forming selective regions of
adhesive material between inner surfaces of the closed end region
of the outer tube body and outer surfaces of the inner tube so that
the closed end of the inner tube is detachably adhered to the
closed end region of the outer tube, so that the inner tube remains
adhered to the outer tube until after the bag is filled to a
selected level with filling material, and so that a user of the bag
can readily remove the inner tube from the outer tube without
damage to the inner tube when the inner tube has filling material
positioned therein.
[0069] A method of using a multiwall bag 20 having a vent seal zone
40 associated therewith, for example, includes filling first and
second multiwall bags 20 with filler material. Each of the first
and second multiwall bags 20 have an inner plastic tube 22, a vent
seal zone 40 formed by a plastic strip 31 attached to a preselected
region 32 of the inner plastic tube 22, and an outer tube 52 formed
of a plurality of layers 57, 58, 59 of porous material attached to
and substantially surrounding the inner tube 22. The inner plastic
tube 22 has a plurality of spaced-apart vent openings 26 and the
plastic strip 31 includes a plurality of spaced-apart vent openings
36 not aligned with the plurality of space-apart vent openings 26
of the inner plastic tube 22 so as to create a tortuous path
therebetween. The vent seal zone 40 also includes a channel space
42 positioned between a surface of the plastic strip 31 and a
surface of the inner tube body 25. The method also includes closing
each of an open end 23 of the first and second multiwall bags 20
after filler material is filled therein and stacking the second
multiwall bag 20 to overlie and contact the first multiwall bag 20
so that pressure from weight of the second multiwall bag 20
increases the air flow from the inner tube 22 of the first
multiwall bag 20, through both the plurality of vent openings 26 in
the inner tube 22 and the plurality of openings 36 in the plastic
strip 31, and through the porous material of the outer tube 52 to
atmosphere (see, e.g., FIGS. 15-16). The method can also include
compressing the first multiwall bag 20 so that trapped gas or air
flows from within the inner tube body 22, through the innermost
plurality of spaced-apart vent openings 26 or 36, through the
channel space 42, along the tortuous path, through the outermost
plurality of spaced-apart vent openings 26 or 36, and into an
innermost layer 57 of the plurality of layers 57, 58, 59 of porous
material, through at least one overlying layer 58, 59 of a
plurality of layers 57, 58, 59 of porous material, and into
atmosphere therefrom.
[0070] Another method of using a bag 20 having a vent seal zone 40
associated therewith, for example, includes filling a bag 20 with
filler material (see FIG. 11). The bag 20, for example, has a
plastic tube 22 including a closed end 24, an open end 23 through
which filler material flows during filling, and a tube body 25
extending between the open end 23 and the closed end 24 and a vent
seal zone 40 defined by a plastic strip 31 attached to a
preselected region 32 of the plastic tube 22. The plastic tube 22
includes a plurality of spaced-apart vent openings 26 and the
plastic strip 31 includes a plurality of spaced-apart vent openings
36. The vent seal zone 40 also includes a channel space 42
positioned between a surface of the plastic strip 31 and a surface
of the tube body 22. The method also includes heat sealing the open
end 23 of the tube body 25 and an upper end of the channel space 42
positioned adjacent the open end 23 of the tube body 25 after
filler material is filled therein to a selected level to thereby
seal the open end 23 of the tube body 25 and the upper end 23 of
the channel space 42 (see, e.g., FIGS. 12-14). The method can also
include compressing the bag 20 so that trapped gas or air flows
from within the tube body 22, through the innermost plurality of
spaced-apart vent openings 26 or 36 of the vent seal zone 40,
through the channel space 42, along the tortuous path, through the
outermost plurality of spaced-apart vent openings 26 or 36 of the
vent seal zone 40 (see, e.g., FIGS. 15-16).
[0071] As illustrated in FIGS. 15-16, in an embodiment of a bag 20,
the method can further include compressing the bag 20. The user
either palletizes or otherwise stacks the bags 20, allowing the
automatic bleed of the trapped gas or air. Alternatively, the user
can manually compress the bag 20 to increase the rate of bleed
prior to stacking. The air or gas, in turn, then passes from the
tube 22 through the porous material of outer tube 52 and generally
will travel along the path of least resistance, such as through
auxiliary slits or openings formed in the porous material first if
these are formed in the outer tube 52 in the innermost layer 57 or
other layers 58, 59. As shown in FIG. 17, in an embodiment, the
method can advantageously include hygienically removing and/or
sterilizing the outer surface of the inner tube 22. Upon arrival at
destination, the end-user may cut or otherwise separate the outer
tube 52 from the inner tube 22. This advantageously provides the
user the ability to then sterilize or otherwise clean the outer
surface of the inner tube 22 prior to unloading the product or
filler material from the inside of inner tube 22.
[0072] In the drawings and specification, there have been disclosed
a typical preferred embodiment of the invention, and although
specific terms are employed, the terms are used in a descriptive
sense only and not for purposes of limitation. The invention has
been described in considerable detail with specific reference to
these illustrated embodiments. It will be apparent, however, that
various modifications and changes can be made within the spirit and
scope of the invention as described in the foregoing specification
and as defined in the attached claims.
* * * * *