Note: Descriptions are shown in the official language in which they were submitted.
CA 02279681 2004-12-29
AUTOMATIC SELF-CLOSING VALVE CLOSURE
ASSEMBLY FOR VALVE BAGS
Background of the Invention
The present invention relates to valve bags that feature a self closing valve
which
closes in response to pressure from the contents of the bag after filling. The
contents are
typically a powdered or granular medium. A valve bag is a container made with
one or more
tubular plies of material, the material usually being a rigid paper such as
kraft paper.
Typically, the valve bag ends are formed by cutting and folding the plies,
thereby forming
flaps on the long sides of the bag end. Flaps are also formed on the short
sides of the bag end.
The short flaps are folded inward and the long flaps are folded over each
other on top of the
short flaps, thus forming the end of the bag. These flaps may be glued or
bonded together to
seal the end of the bag. The bag is usually folded to form corner tucks
extending from both
short sides of the bag end resulting in a satchel-type rectangular
configuration. These corner
tucks may be folded inward from the sides of the bag. When the bag is filled,
these corner
tucks unfold and cause the bag
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CA 02279681 1999-08-OS
end, top or bottom, to take the rectangular shape. This type of bag is usually
called a satchel
bag.
A valve bag is most often a satchel bag which features a channel formed on one
of the
short sides of the filling end of the bag. This channel is typically a
flattened tube which is
inserted during bag manufacturing on one side of the bag end before the flaps
are folded and
sealed together. The channel may also be formed by leaving the two flaps on
the long side
of the bag end unsealed to the flap on the short side. The channel and the
length of the flap
on the short side form a passage, which allows access to the interior of the
bag for filling it
with contents. The folded short side flap may extend further into the bag than
the channel,
such as that disclosed in Kelley et al., U.S. Pat. No. 5,516,210, thus
providing a closure or
shutoff for the valve. The valve is closed by the contents of the bag pushing
this flap against
the sealed long side flaps of the bag end. When the prior art valves are
closed, the contents
of the bag are supposed to be prevented from sifting out of the channel. Thus,
there is no
need to immediately heat or sonically seal the bag after it is filled. This
allows the bag to be
sealed immediately or at another location on the production line in the
filling process of the
bag user. In another embodiment, having particular suitability to large width
satchel-type
bags, the valve assembly automatically achieves full closure with no final
sealing step
required subsequent to filling the bag with product.
The main goal of prior art sealable valve bags has been to prevent the sifting
or
leakage of the bag contents back through the channel of the valve after
filling. This goal was
addressed by the initial mechanical closing or sealing of the valve in order
to prevent such
sifting or leaking. Known sealable valve bags have utilized a valve formed
from a flattened
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CA 02279681 1999-08-OS
tube. This tube usually extends outward from the short side of the bag end in
order to
provide an adequate length of material for the sealing process. For the final
sealing closure,
the inner surface of the tube is typically coated with an adhesive or other
sealing material,
which may be activated by heat, pressure, or ultrasonic means. Other valve bag
constructions rely on hot melt glue to provide a final seal to the valve. When
the packer is
ready, valve bags are filled by means of a filling nozzle which is inserted
into the valve
channel. When the bag is full, the nozzle is removed and the valve opening is
then ready to
be finally sealed.
While some of the sifting problems have been prevented by these previously
used
sealable valve bags, they still have limitations inherent in their structure.
Sifting and spillage
may yet occur when the filling nozzle is removed. This is partially due to the
memory of the
rigid valve material after removal of the nozzle. Prior art bags which were to
be finally
sealed at a remote location down the manufacturing line, distant from the
filling point, spilled
out product between these two stages of the process. Even valve bags which
have had an
extended short side flap in order to close off the valve channel, nonetheless
have still allowed
sifting around the sides of this flap, resulting in spillage through the valve
opening during
transport to the final sealing station. This spillage also affects the seal
quality by
contaminating any opposing sealing surfaces prior to the sealing process.
Furthermore, since
the prior art valve constructions have typically utilized only the plies of
the bag to support
the valve tube, they have been susceptible to tears or damage during the
filling process.
It is therefore an object of the present invention to provide a sealable valve
bag
assembly, which upon filling, immediately creates a mechanical seal lock along
the standard
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parallel fold lines of a satchel-type bag end at the bag-inward opening of the
valve tube,
thereby sealing both sides of the valve tube in the fold lines and eliminating
any possible
channeling of the bag contents through and alongside the valve tube prior to a
final sealing
step.
In an alternate embodiment, it is a goal of the invention to eliminate a final
sealing
step whereby the valve assembly automatically reaches full closure upon
filling the bag with
product.
It is a further object of the present invention to provide a seal tab lock
which extends
beyond the innermost edge of the short side flap of the bag, thus creating a
flap valve which
purposely prevents filled product from escaping back out the valve tube before
the valve is
ultimately sealed by heat, sonic, pressure, adhesive means, or the like.
It is still another object of the present invention to provide a seal tab lock
which is
attached to the valve bag assembly, but not formed from the valve bag plies,
thus adding
strength and support to the valve side of the bag end in order to prevent
tears or ruptures in
the valve area during and after the filling operation.
CA 02279681 1999-08-OS
Summary of the Invention
The present invention is a valve closure assembly, preferably sonically
sealable, for
use in valve bags. The valve bag is a container formed from tubular-shaped
plies of material,
the ends of the bag being formed by cutting the bag material at the corners of
the bag end
and folding short sides of the bag end inward, thus creating two flaps along
long sides of the
bag end. A seal tab lock is disposed and affixed on one of the short sides of
the bag end
where the valve will be located, the seal tab lock also being positioned over
the parallel fold
lines of the long side flaps of the bag end and extending past both fold lines
by an equal
length. The seal tab lock is also positioned so that it extends over the inner
edge of the
longest corner infold of the short side of the bag end. A valve tube is
disposed and affixed
over the seal tab lock and offset by a predetermined distance so that the seal
tab lock extends
further into the inner portion of the bag than the inside end of the valve
tube. This offset also
results in the valve tube extending outwardly from the short side of the bag
end. The long
side flaps on the bag end are then folded over each other at the parallel fold
lines and sealed
so that the bag end is formed with the valve tube exposed from one side of the
bag end.
Upon filling the bag with the intended product, the seal tab lock, which is
affixed to
the short side of the bag end before the valve tube is affixed, and also
before the long side
flaps are folded inward and sealed, forms a barrier around the sides of the
inner valve tube
end and a mechanical closure for the valve tube inside the bag. The side
barrier is formed
by extended portions of the seal tab lock inside the bag and along the
parallel folds formed
by the long side flaps on the bag end. When the long side flaps are folded
inward, the
extended portions are also folded over, thus creating the seal lock. The
offset positioning of
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CA 02279681 1999-08-OS
the valve tube in relation to the seal tab lock results in the seal tab lock
extending further into
the bag than the inner valve tube opening, thereby creating a flap valve
closure action, which
effects a valve tube closure prior to sealing.
In a preferred embodiment of the invention, the width of the seal tab lock
equals the
width of the valve size specified plus one inch for use with a full width
valve. A seal tab lock
may also be specified for a reduced valve by providing a wider seal tab lock.
Preferably, the
width of the seal tab lock will allow enough material to fold over the valve
tube in order to
create seal tabs along the sides of the valve tube. 'The valve tube material
is preferably a
heavy paper, or other rigid material, which allows for easy insertion of a
filling nozzle. The
heavy paper also prevents tearing or damage to the valve tube during or after
the filling
process. The inside surface of the valve tube is preferably pre-coated with a
sealable material
to allow sealing of the valve tube by heat, sonic, pressure, adhesive means,
or an equivalent.
In an alternate related invention, a final sealing step is eliminated. The
valve
assembly automatically self closes upon filling the bag with product. A seal
lock is used
having folded and overlapping paper and thin film plastic layers, or all
overlapping paper
layers, fully wrapping a reduced width valve tube for large size satchel-type
bags.
Brief Description of the Drawings
FIG. 1 is a perspective view of a satchel end of an assembled multiple ply
valve bag
at the bag end having the valve assembly.
FIG. lA is a perspective view showing the valve assembly removed from the
valve
bag.
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FIG. 2 is a plan view of the unassembled valve bag end of FIG. 1 showing the
long
side flaps of the multiple bag plies formed by cutting the corners of the
valve bag and the
short side flaps of the multiple bag plies folded inwardly.
FIG. 3 is a plan view of the bag end having the valve assembly showing the
assembly
placement step for the seal tab lock shown exploded away and in dashed lines
with respect
to the flaps and parallel fold lines of the bag end.
FIG. 4 is a plan view of the bag end having the valve assembly showing the
assembly
placement step for the sonic valve tube shown exploded away and in dashed
lines with
respect to the seal tab lock and the parallel fold lines of the bag end.
FIG. 5 is a plan view of the bag end having the valve assembly showing a full
width
valve assembly shown prior to the folding of the long side flaps of the bag
end.
FIG. 6 is a plan view of the bag end similar to FIG. S and having a valve
assembly
in an alternate embodiment for a reduced size valve assembly shown prior to
the folding of
the long side flaps of the bag end.
FIG. 7 is a plan view of an entire assembled valve bag with a full width valve
assembly.
FIG. 8 is a plan view of an entire assembled valve bag with a reduced width
valve
assembly.
FIG. 9 is a cross-sectional side view of the bag end at the valve assembly
before
filling.
FIG. 10 is a cross-sectional side view of the bag end at the valve assembly
during
filling by the filling nozzle inserted into the valve.
s
CA 02279681 1999-08-OS
FIG. 11 is a cross-sectional side view of the bag end at the valve assembly
showing
a filled valve bag and sonic sealing apparatus for sealing the valve closed.
FIG. 12 is a perspective view of a satchel end of an assembled multiple ply
valve bag
at the bag end having an alternate embodiment of the valve assembly.
FIG. 12A is a perspective view showing the alternate embodiment of the valve
assembly of FIG. 12 removed from the valve bag.
FIG. 13 is a plan view of the bag end having the alternate embodiment of the
valve
assembly of FIG. 12 showing the assembly placement step for the seal tab lock
shown
exploded away and in dashed lines with respect to the flaps and parallel fold
lines of the bag
end.
FIG. 14 is a plan view of the bag end having the alternate embodiment of the
valve
assembly of FIG. 12 showing the assembly placement step for the sonic valve
tube shown
exploded away and in dashed lines with respect to the seal tab lock and the
parallel fold lines
of the bag end.
FIG. 15 is a plan view of the bag end having the alternate embodiment of the
valve
assembly of FIG. 12 showing the valve assembly prior to the folding of the
long side flaps
of the bag end.
FIG.16 is a perspective view of a satchel end of an assembled multiple ply
valve bag
at the bag end having another alternate embodiment of the valve assembly.
FIG. 16A is a perspective view showing the alternate embodiment of the valve
assembly of FIG. 16 removed from the valve bag.
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FIG. 17 is a plan view of the bag end having the alternate embodiment of the
valve
assembly of FIG. 16 showing the assembly placement step for the seal tab lock
shown
exploded away and in dashed lines with respect to the flaps and parallel fold
lines of the bag
end.
FIG. 18 is a plan view of the bag end having the alternate embodiment of the
valve
assembly of FIG. 16 showing the assembly placement step for the sonic valve
tube shown
exploded away and in dashed lines with respect to the seal tab lock and the
parallel fold lines
of the bag end.
FIG. 19 is a plan view of the bag end having the alternate embodiment of the
valve
assembly of FIG. 16 showing the valve assembly prior to the folding of the
long side flaps
of the bag end.
FIG. 20 is a perspective view of a satchel end of an assembled multiple ply
valve bag
at the bag end having another alternate embodiment of the valve assembly.
FIG. 20A is a perspective view showing the alternate embodiment of the valve
assembly of Fig. 20 removed from the valve bag.
FIG. 20B is an exploded view of the alternate embodiment of the valve assembly
of
Fig. 20.
Detailed Description of the Invention
A typical valve bag 20 has a tubular configuration with long sides 22 and 23,
and
short sides 24 and 25, as shown in FIG. 1. For simplicity of illustration,
only one bag end
26 with a valve assembly 10 is shown. After final assembly of the valve bag
20, a valve tube
2 extends from the valve side 28 of the bag end 26 and provides a valve
channel 4 in order
to
CA 02279681 2005-04-08
to access the inside of the valve bag 20. The valve bag 20 is usually
constructed with one or
more paper plies A, B, and C, and is provided with a step pattern 60 at the
bag end 26 as
illustrated in FIG. 2.
The first step of the sonic valve bag construction depicted in FIG. 2 is to
cut the paper
plies A, B, and C of the bag end 26, thus creating cut lines 52, 54, and 56.
Short side flaps
36 and 38 are folded inward, creating fold lines 42 at the short sides 24 and
25 of the bag end
26 and also creating flaps 32 and 34 along the long sides 22 and 23 of the bag
end 26. Parallel
fold lines 40 are created to allow the flaps 32 and 34 to fold inward during
the final assembly.
This construction creates a known type of satchel bag end with outwardly
folded gussets 14
and 16 formed by the fold lines 42 at the short sides 24 and 25 of the bag end
26. When the
bag 20 is filled with contents, gussets 14 and 16 unfold and cause the bag end
26 to take a
rectangular shape.
A seal tab lock 3 is disposed on the short side flap 38 as shown in FIG. 3 and
is
centered upon the fold lines 40, so that an equal length of the seal tab lock
3 extends over
each fold line 40, thus creating folded-over tab locks 3a and 3b. The seal tab
lock 3 is further
disposed so that an inner edge 3c extends over an innermost edge 66 of the
short side flap 38
by a predetermined distance, this distance being about two inches in the
preferred
embodiment. This inward extension distance can be longer if the filling nozzle
opening 82
shown in FIG. 10 allows, but preferably is no less than about one and one half
inches. The
seal tab lock 3 in the preferred embodiment is a 50 pound super (high)
performance kraft
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(SPK) paper. The seal tab lock 3 may be formed from the same material as the
plies of the
bag 20.
A valve tube 2 is then disposed on the seal tab lock 3 and positioned such
that the
valve tube 2 is offset toward the valve side 28 by a predetermined distance,
allowing the
inner portion of the seal tab lock 3 to extend past the inner opening 6 of the
valve tube 2 and
creating a flap valve 9 portion of the seal tab lock 3, as shown in FIG. 4.
The offset distance
in the preferred embodiment is one quarter inch towards the valve side 28 from
the innermost
edge 66 of the short side flap 38, plus or minus one quarter inch. The length
of the valve tube
2 is dictated by the satchel size of the valve bag 20 and the sealing
equipment requirements.
The material of the valve tube 2 is preferably a heavy paper, or other rigid
material, such as
a 70 pound natural kraft paper, or equivalent. An example of a suitable
alternative material
for the valve tube 2 is 60 pound bleached white kraft paper. The invention is
not limited to
forming the valve tube 2 or the seal tab lock 3 only from paper as other
suitable materials are
envisioned, including plastic polymers.
An inside surface 1 of the valve tube 2 is coated with a special blend of
coatings for
use in the sealing process. The preferred coating for ultrasonic sealing is
polyethylene
applied in the proportion of about 40 to 50 pounds of coating per ream of
paper. The
preferred formulation for the polyethylene coating has the proportion of about
40% +l- 5%
by weight of low density polyethylene with metallocene and about 60% +/- 5% by
weight
of high density polyethylene. The coating may also include an anti-static
ingredient. An
example of a suitable alternative coating is #1652 slip additive resin, sold
under the brand
name SURLYN by E. I. DuPont deNemours Chemical Company. To prevent curling,
the
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CA 02279681 1999-08-OS
outer surface of the seal tube may be coated with an anti-curling coating.
Other coatings may
be used for different sealing processes. The valve tube 2 may be coated with
other equivalent
sealing compositions that may be alternatively sealed through heat, adhesive,
or pressure
means, as would be understood by those skilled in the art.
FIG. 5 shows the seal tab lock 3 and the valve tube 2 affixed to the short
side flap 38
of the bag end 26.
FIG. 6 shows the seal tab lock 3 and the valve tube 2 formed in different
dimensions,
affixed to the short side flap 38 of the bag end 26, thereby forming a reduced
size alternate
embodiment of the valve assembly 10. The width of the seal tab lock 3 for a
full width valve
in the exemplary embodiment is determined by adding one inch to the width of
the valve tube
2. For standard 40-60 pound capacity paper valve bags, the full width valve
manufacturing
range is from about three to about nine inches. The width of the seal tab lock
3 for a reduced
valve in the disclosed embodiment is determined by adding the width of the bag
end 26 to
the difference between the width of the bag end 26 and the width of the
specified reduced
valve tube 2, plus one inch. The extra width in this formula is for the
purpose of providing
enough material for the seal tab lock 3 to cover widest gaps 12 between sides
7 and 8 of the
valve tube 2 and the parallel fold lines 40, as shown in FIG. 6. The reduced
valves have a
manufacturing range from about three to about eight and three quarter inches
for the
disclosed alternate embodiment.
In the final steps of assembly, the flap 32 is folded inward over the valve
tube 2 and
the flap 34 is folded over the flap 32 along the fold lines 40, thereby
resulting in the tab locks
3a and 3b of the seal tab lock 3 being folded around and on top of the valve
tube 2, as shown
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CA 02279681 1999-08-OS
in FIG. 1. FIG. lA shows an isolated view of the assembled valve tube 2 and
seal tab lock
3 showing the tab locks 3a and 3b of the seal tab lock 3 folded around the
valve tube 2. In
the preferred embodiment, the tab locks 3a and 3b are integrally joined to the
side edges of
the seal tab lock 3 and wrap around or over the top of the valve tube 2 for
one half inch
margins along each side. This provides a complete seal under the valve tube 2
and along the
parallel fold lines 40, leaving no channel for the contents to leak out. The
flap 34 is then
sealed to the flap 32, preferably by pasting, as is known in the bag-making
arts, to complete
the assembly. The tab locks 3a and 3b create a seal around the inner opening
of the valve
tube 2 which, along with the flap valve 9, prevent outward channeling or
sifting of the
contents of the valve bag 20 during and after the filling process.
FIG. 7 and FIG. 8 are plan views of the preferred embodiments for the final
assemblies of the full width valve version and the alternate reduced valve
version of the valve
bag 20, respectively.
FIG. 9 is a vertical cross-section taken at the valve side 28 of an assembled
empty
valve bag 20 ready to be filled. The cross-section reveals the paper plies A,
B, and C of the
valve bag 20, however the invention is not limited to bags having three plies.
The valve tube
2 is shown in a closed but unsealed position with the flap valve 9 of the seal
tab lock 3 in an
open position. The valve bag 20 is filled by inserting a filling nozzle 80
into the valve
channel 4 of the valve tube 2, expanding it open, as shown in FIG. 10. The
filling nozzle
80 extends past both the inner opening 6 of the valve tube 2 and an inner edge
5 of the flap
valve 9. The valve bag 20 is then filled with contents 100, which would
typically be a
granular, powdered, or comminuted product, such as dry powdered milk. As the
contents
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CA 02279681 1999-08-OS
100 inside the valve bag 20 reach the filling nozzle 80, they push flap valve
9 towards the
inner surface of the bag end 26. When filling is complete and the filling
nozzle 80 is
removed, the pressure from the contents 100 of the valve bag 20 forces the
flap valve 9 and
the tab locks 3a and 3b against the inner surface 29 of the bag end 26,
thereby providing a
mechanical closure or shutoff of the inner opening 6 of the valve tube 2. The
valve tube 2
is also flattened against the inner surface 29 of the bag end 26 from the
pressure of the
contents. When the filling nozzle 80 is removed, the tab locks 3a and 3b of
the flap valve
9 prevent the contents from channeling or leaking around the flap valve 9 and
sifting back
outwardly of the valve channel 4 of the valve tube 2, thus providing an
effective closure
between the sides 7 and 8 of the valve tube 2 and the inside of the valve bag
20 prior to final
sealing of the valve tube 2.
In the disclosed embodiment, the final sealing is illustrated in FIG. 11 and
comprises
a sonic sealing process performed by a sealing apparatus 70 located on the
manufacturing
line. The valve bag 20 can be transported to the sealing apparatus 70 via a
conveyor system.
Sifting and spillage of the contents of valve bag 20 are prevented during the
transfer to the
sealing apparatus by the function of the tab locks 3a and 3b and the flap
valve 9 as described.
The prevention of such spillage allows bags from several filling lines to be
transported to
distant sealing apparatus stations or other handling procedures. This
eliminates the
requirement of having a sealing apparatus on each filling line. The sonic
sealing of the valve
bag 20 may be performed by a typical sealing apparatus 70, such as generator
head 72 and
anvil 74 shown in FIG. 11. The valve tube 2 extends outwardly from the valve
side 28
CA 02279681 1999-08-OS
allowing ample material for the valve tube 2 to be sealed by the sealing
apparatus 70
alongside the valve bag 20, as also depicted in FIG. 11.
FIG. 12 shows the assembled valve bag 20 having an alternate embodiment valve
assembly 110. FIG. 12A is an isolated view of the valve assembly 110 showing
tab locks
103a, 103b, 103g, and 103h folded around a valve tube 102. In this embodiment,
a seal tab
lock 103 is folded under itself along an outside edge 103d of the seal tab
lock I03 prior to
being disposed on the bag 20, thus forming folded portion 103e and leading
edge 103f, as
shown in FIG. 13. The folded portion 103e and the tab locks I03g and 103h
provide a
second, or double, barrier to prevent sifting of material between the folded
flaps 32 and 34
of the valve bag 20 and the seal tab locks 103a and 103b of the valve assembly
110, as well
as possible sifting between the seal tab lock 103 and the short side flap 38.
The tab locks
103g and 103h of the folded portion 103e also provide added strength to the
tab locks 103a
and 103b in order to help prevent tearing during the filling and sealing
process.
The valve assembly 110 is assembled and attached to the valve bag 20 in much
the
same way as the other valve assemblies disclosed herein. The seal tab lock 103
with folded
portion 103e is disposed on the short side flap 38 and is centered upon the
fold lines 40, so
that an equal length of the seal tab lock 103 extends over each fold line 40,
thus creating
folded-over tab locks 103a, 103b, 103g, and 103h, as shown in FIG. 13. The
seal tab lock
103 is further disposed so that an inner edge 103c extends over an innermost
edge 66 of the
short side flap 38 by a predetermined distance, this distance being about two
inches in the
preferred embodiment. This inward extension distance can be longer if the
filling nozzle
opening 82 shown in FIG. 10 allows, but preferably is no less than about one
and one half
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CA 02279681 1999-08-OS
inches. The valve tube 102 is then disposed on the seal tab lock 103 and
positioned such that
the valve tube 102 is offset toward the valve side 28 by a predetermined
distance, allowing
the inner portion of the seal tab lock 103 to extend past the inner opening
106 of the valve
tube 102 and creating a flap valve 109 portion of the seal tab lock 103, as
shown in FIGs.
12A, 14 and 15.
FIG. 16 shows the assembled valve bag 20 having yet another alternate
embodiment
valve assembly 210. The valve assembly 210 utilizes a two-piece seal tab lock
configuration
200 consisting of a main layer 203, typically made of paper, and an offset
layer 205,
typically made of a thin plastic film. The main layer 203 and the offset layer
205 of the two-
piece seal tab lock 200 have tab locks 203a, 203b and 205a, 205b,
respectively, folded
around a valve tube 202 in FIG. 16A. FIG. 17 further shows the main layer 203
and the
offset layer 205 to additionally have tab locks 203g, 203h, and 205g, 205h,
respectively, of
the two-piece seal tab lock 200. In this embodiment, the offset layer 205 is
positioned such
that an inner edge 205c of the offset layer 205 overlaps an inner edge 203c of
the main layer
203 of the two-piece seal tab lock 200. This overlap creates a two-layer flap
valve 209 up
to the inner edge 203c and a single layer therepast at 209' comprising the
offset layer 205
alone. Typically the offset layer 205 is made of a thin plastic film which
provides aid in
sealing off the valve when product pressure forces the flap valve 209 and
209'closed. When
filling is complete, the pressure from the contents of the valve bag 20 forces
the flap valve
209 and 209' against the inner surface of the bag end 26, thereby providing a
mechanical
closure or shutoff of the inner opening 206 of the valve tube 202. The thin
plastic film of the
offset layer 205 is very limp and provides for a well-sealed shutoff.
17
CA 02279681 1999-08-OS
Both the offset layer 205 and the main layer 203 are folded over along their
outside
edges 203d and 205d prior to being disposed on the valve bag 20, thus forming
folded
portions 203e and 205e, and leading edges 203f and 205f, as shown in FIG. 17.
These
portions are first folded over the top of the two-layer seal tab lock 200,
unlike the seal tab
lock 110 in FIG. 12A where the folded portion 103e is first folded under the
tab lock 110.
Thus, the folded portion 205e of the thin plastic film is captured by the
folded portion 203e
of paper. The folded portions 203e and 205e and the tab locks 203g, 203h,
205g, and 205h
provide a second, or double, barrier to prevent sifting of material between
the folded flaps
32 and 34 of the valve bag 20 and the tab locks 203a, 203b, 205a, and 205b of
the valve
assembly 210, as well as preventing sifting between the seal tab lock 203 and
the short side
flap 38. The tab locks 203g, 203h, 205g, and 205h of the folded portions 203e
and 205e also
provide added strength to the tab locks 203a, 203b, 205a, and 205b in order to
help prevent
tearing during the filling and sealing process.
The two-piece seal tab lock 200 with the folded portions 203e and 205e is
disposed
on the short side flap 38 as shown in FIG. 17 and is centered upon the fold
lines 40, so that
an equal length of the two-piece seal tab lock configuration 200 extends over
each fold line
40, thus creating the folded-over tab locks 203a, 203b, 203g, 203h, 205a,
205b, 205g, and
205h. The two-piece seal tab lock 200 is further disposed so that an inner
edge 205c extends
over an innermost edge 66 of the short side flap 38 by a predetermined
distance, this distance
being about two inches in the preferred embodiment. This inward extension
distance can be
longer if the filling nozzle opening 82 shown in FIG.10 allows, but preferably
is no less than
about one and one half inches. The valve tube 202 is then disposed on the two-
piece seal tab
18
CA 02279681 1999-08-OS
lock 200 and positioned such that the valve tube 202 is offset toward the
valve side 28 by a
predetermined distance, allowing the inner portion of the two-piece seal tab
lock 200 to
extend past the inner opening 206 of the valve tube 202, thus forTning the two-
piece flap
valve 209, as shown in FIGs. 16A, 18 and 19.
FIGS. 20, 20A and 20B illustrate a related invention in a preferred embodiment
thereof. Typically in the industry, large width satchel-type bags have been
made with
reduced valve tube sizes, such as for satchel bottom standard widths of from
about six to nine
inches. A common size large width satchel-type bag has a nominal width of
eight inches.
The utilization of a less than full width valve tube provides for a cost
savings in material.
Because this smaller valve tube does not extend fully across the width of the
bag, gaps
between the valve tube and sides of the bag and flap valves create the danger
of tearing or
rupturing the valve assembly during filling and handling. Attempts at
providing a reduced
valve tube also have utilized thin polyethylene film closure flaps, but these
too create
problems involving bag rupturing and splitting, because there is little
strength between the
reduced valve tube and the fold lines of the satchel bottom, such as at lines
40 previously
described in reference to FIGS. 1-16.
In addition to the reduction of costs by using a reduced valve tube, the
industry has
sought to further eliminate costs for sealing large size satchel bags. The
utilization of a sonic
sealing valve tube, such as shown in FIG. 6 above, while effective for its
intended purposes,
adds cost in terms of providing a coating to the interior of the valve tube
with a sonic sealable
material, as described above, requiring a further sealing step, and also in
regard to the
19
CA 02279681 2005-04-08
additional material for the valve tube that has to project bag-outwardly for
the sealer to seal,
i.e., the extension of valve tube 2 outward of the bag side 28, as shown in
FIG. 1.
In FIGS. 20, 20A and 20B, an improved reduced valve assembly 510 is shown,
which
provides for an automatic self closing, final sealing without the need for
further adhesives,
sonic sealing, hot melts, sealing tape, stitching, or the like. The valve
assembly 510 is a
tri-partite assembly that is related to the valve assembly 210 as shown in
FIGS.16,16A, and
17. The valve assembly 510 improves upon the valve assembly 210, and affords
particular
suitability to closing larger vvdth satchel-type bottom bags.
The valve assembly 510 embodies modifications to the valve assembly 210 by
providing folded-over, nested portions of a seal lock 503 and offset plastic
layer 505. Further,
the seal lock 503 and offset layer 505 have a sufficient lateral dimension, in
relation to the
width of the bag side 28, whereby to overlap at O and O' to provide a fully
peripherally
wrapping sleeve-like arrangement around a valve-tube 502.
In the illustrative example, and as in the previous descriptions, the valve
bag 20 has
a satchel-type bag end 26 having a width of about eight inches, which reflects
a common
large size satchel-type bag well known in the industry. The seal lock 503 is
made of 30-80
pound high performance paper. The offset layer 505 is preferably made of thin
polyethylene,
preferably thinner than the thickness of the seal lock 503. The outward edge
of the seal lock
503, valve tube 502 and bag side 28 are substantially co-terminate, i.e.,
ending in the same
vertical plane, as shown in FIG. 20 and as more specifically described
hereinafter. Because
the valve assembly 510 is automatically self closing, the valve tube 502 need
not extend from
the bag outwardly and thus offers material cost savings. Of course, the valve
assembly 510
CA 02279681 2005-04-08
would still be automatically self closing if the valve tube 502 did extend
from the bag
outwardly, but this is a waste of material.
As previously described, the valve bag 20 has long sides 22, 23, a bag end 26,
and a
valve side 28 where a short side 24 meets the bag end 26. The satchel-like bag
end 26 is
formed by folded longer flaps 32, 34 and short side flaps 36, 38. The valve
assembly 510 is
generally associated with the bag end 26 in the same manner as shown for the
valve assembly
210 in FIGS.16 and 17, however the valve tube 502 is narrower, the seal lock
503 and offset
layer 505 are nested in folds and overlapped to make a sleeve, and the valve
tube 502 is
shortened to terminate at the outward side of the seal lock 503. As shown in
FIG.16, the seal
tab lock 203 is not folded upon itself and does not overlap. Likewise the
offset layer 205 is
not folded over itself and is not overlapping. The seal lock 503 includes tab
locks 503a,
503b, 503g and 503h. A folded over portion 505e makes the tab locks 503g and
503h to be
double-layered and form a pocket for the offset layer 505, as will be
understood in connection
with FIG. 20B. The seal lock 503 includes an inner edge 503c, an outer edge
503d, and
another inner edge 503f created by the folding of folded portion 503e. The tab
locks 503a,
503b, 5038 and 503h have sufficient width whereby to overlap when folded
around fold lines
F and FF to provide the overlap O, which in the illustrated embodiment is
approximately one
inch. As in previous embodiments, the fold lines F and FF generally correspond
to the fold
lines 40 of the bag end 26. Thus, the dimensions L shown to the sides of the
fold lines F and
FF would add to equal the width of the bag end 26 plus two inches in the
disclosed
embodiment.
21
CA 02279681 1999-08-OS
The formation of the folded portion 505e of the seal lock 505 provides a
pocket-like
configuration for the retention or capture of a portion of the offset layer
505. The offset layer
505 includes opposing tab locks 505a and 505b, and further has an inner edge
505c and an
outer edge 505d. A folded portion SOSe corresponds to, but is not as long as,
the folded
portion 503e. The folded portion 505e extends bag inwardly from the outside
edge 505d and
forms tab locks 505g and 505h, which are folded in the same direction as the
tab locks 505g
and 505h. The tab locks 505g and 505h are nested within the pocket-like folded
configuration of said portion 503e. In the disclosed embodiment, the folded
portion 503e is
approximately twice the length of the folded portion 505e. An inner or leading
edge 503f of
the seal lock 503 thereby projects farther bag-inwardly than an inner leading
edge 505f of the
offset layer 505, however stopping short of projecting to an inner opening 506
of the valve
tube 502, best viewed in FIG. 20B. As with the seal lock 503, the offset layer
505 has a
sufficient lateral dimension allowing the tab locks SOSa, 505b, 505g and 505h
to provide an
overlap O' of approximately one inch, as shown in FIG. 20A. Along the overlaps
O and O',
the seal lock 503 and offset layer 505 are adhered together during the making
of the bag 20,
preferably by use of a hot melt, thereby trapping the offset layer 505 within
the folded
portion 503e. In order to secure the offset layer 505 and to prevent it from
shifting, because
it is preferably made of a thin plastic film that can shift, the offset layer
505 is laterally
stepped, or shifted, to displace its outside later edge 5051 a short distance
from an outside
edge 5031 of the seal lock 503, also as best viewed in FIG. 20B. In the
disclosed
embodiment, the shifting shown at S is about one-quarter inch. It generally
would fall in the
range of from about 1/16 to 3/8 inches. This shift, or stepping S, thereby
provides a small
22
CA 02279681 1999-08-OS
stepped-out part of the offset layer 505 relative to the seal lock 503 to
allow the adhesive to
come into contact with both the seal lock 503 and the offset layer 505 along
the overlaps O
and O'. The stepping S could either be in either lateral direction, i.e.
leftward or rightward
depending upon whether the tab locks 503a, 503g overlap 503b, 503h yr vice
versa. As
shown in FIG. 20A, the tab locks 503a and 503g overlap tab locks 503b and 503h
accordingly, the shifting S is shown in the rightward direction of the arrow
for step S in FIG.
20B. Due to the overlaps O and O', there is no gap between the tab locks 503a,
503g and
503b, 503h of the seal lock 503, or between the tab locks 505a, 505g and 505b,
505h of the
offset layer 505 contrary to the relationships of the tab locks shown for seal
tab lock 203 and
offset layer 205 of the embodiment for valve assembly 210. The valve assembly
210 leaves
a gap across the top of the valve tube 202.
The valve assembly 510 provides a two-layer flap valve 509 and single layer
flap
valve 519, the later of which is created by the inward offsetting of the seal
lock 503 and
offset layer 505 from the inner opening 506 of the valve tube 502.
Specifically, in reference
to FIG. 20B, it would be understood that product filling inside the valve bag
20 will push
upward against both the seal lock 503 and offset layer 505 at the flap valve
509 and press
against both of these layers. However, from the inner edge 503c of the seal
lock 503 to the
inner edge of 505c of the offset layer 505, at the flap valve 519, only the
thin plastic offset
layer 505 would be pushed and compressed upwardly by the product. Thus, at the
flap valve
509, the portions of the seal lock 503 and offset layer 505 above and below
the valve tube
502 are both pressed together. Inwardly of the inner edge 503c of the seal
lock 503, at the
flap valve 519, only the portions of the offset layer 505 above and below the
valve tube 502
23
CA 02279681 1999-08-OS
would be pressed together in a sealingly tight relationship. In further
achievement of this
sealing closure, the pocket-like portions formed by the folded portions 503e
and 505e will
be observed to form a trapping double collar encircling the valve tube 502 in
order to further
prevent sifting of material between the valve assembly 510 and the paper plies
of the bag end
26 and also along gaps G and GG formed between the valve tube sides 507 and
508 and fold
lines F and FF, respectively, as shown in FIGs. 20 and 20B. These folded
portions 503e and
505e create a peripheral trap for catching particles and comminuted or
granulated materials
seeking to otherwise sift and leak outwardly of the bag during filling.
In the illustrative embodiment, the width of the valve tube 502 is slightly
less than
two-thirds of the width of the bag end 26. Accordingly, in the disclosed
embodiment, the
gaps G and GG are approximately one and one-half inches each. T'he valve tube
502 has a
width in the range of from about 50% to 80% of the width of the bag end 26.
T'he valve tube 502 has an outer opening, or outer end 511, which is
coterminous with
the outward edge 503d and valve side 28 of the valve bag 20. T'he valve tube
502 has an
inner opening 506 through which the product is passed into the bag interior.
In the disclosed
embodiment the length of the valve tube 502 between the outer opening 511 and
inner
opening 506 is substantially the same as the distance between the outer edge
503d and inner
edge 503c of the seal lock 503, herein is about four and one-half inches. T'he
offset layer 505
extends bag inwardly of the edge 503c approximately three and three-quarter
inches, but this
dimension may vary, as long as the flap valve 519 has sufficient surface area
to provide
effective sealing closure bag inwardly of the inner edge 503c of the seal lock
503.
24
CA 02279681 1999-08-OS
The valve tube 502, like the valve tube 202 of the valve assembly 210,
includes an
inner surface 501. However, the inner surface 501 need not be provided with
any sealable
coating, because a sonic or other final sealing is not required for the valve
assembly 510.
The valve tube 502 also has a valve channel 504 extending between the outward
opening 511
and inner opening 506 into which a filling nozzle, such as nozzle 80 shown in
FIG. 10, may
be inserted for injecting product into the valve bag 20.
Similar to the assembly of the valve assembly 210 with the bag valve 20 shown
in
FIGS. 17 and 18, the assembly of the valve assembly 510 with the valve bag 20
is achieved
by placing the seal lock 503, having pocketed at its portion 503e the folded
portion 505e of
the offset layer 505, onto the unfolded satchel bottom 26 of the valve bag 20.
Thereafter, the
valve tube 502 is similarly placed and glued onto the folded-together seal
lock 503 and offset
layer 505, as shown in FIG. 20B. The seal lock 503 and offset layer 505 are
then folded
around the fold lines F and FF with the bag flaps along fold lines 40,
whereupon starch based
adhesive, or the like, adheres the valve bag 20 to the valve assembly 510.
As a result, the valve assembly 510 provides a tri-partite arrangement of a
valve tube
502, seal lock 503 and offset layer 505 providing a reduced valve tube width
and an
automatically self closing valve with no outward extension, thereby
eliminating a final
sealing. The valve bag 20 requires no firrther mechanical closure or sealing
step on the
production line. Accordingly, the utilization of the valve assembly 510 for
the larger size
satchel-bottom bag satisfies the needs of the industry for filling such type
bags with
comminuted fine, granular materials without leakage or sifting.
is
CA 02279681 1999-08-OS
While specific embodiments of the present invention have been shown here for
the
purposes of explaining preferred and alternate embodiments of the inventions,
it is to be
understood that the appended claims have a wide range of equivalents and a
broader scope
than the embodiments disclosed.
26
