Note: Descriptions are shown in the official language in which they were submitted.
405060-2060
PATENT
.UET~CD OF FILLING AND SEALING
A DFFORMABLE CO~JTAINF:R 2 0 3 ~ 3 8 Q
BACKGF~OUND OF THE ~NVENTION
This invention relates to a method of filling and
sealina a container with a product, and more particularly, to
a method of producing a package in which the integrity of the
seal is preser~ed and voids within the container are virtually
eliminated.
Prior methods for filling and sealing a container
have provided a substantial "headspace" within the container
in order that the seal area of the container is not
contaminated ~Jith the product, which will result in incomplete
and leaking seals.
This headspace gas hinders exploitation of
sterilizable containers, because of the difficulty of
accurately controllir.a the pressure within the containers
during temperature changes, to ensure the seals are not
ruptured or containers otherwise deformed or damaged. If the
headspace gas is air, this will cause spoilage of
oxygen-sensitive products.
This headspace also has the appearance of a
partially filled container, giving a poor value impression to
the consumer.
Additionally, the headspace allows movement of
product during shipment, resulting in stressing of the lid
material (which mav rupture), and also damage to the product.
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2038380
It is well known to use a diaphragm of stretchable lid material to
close a container which is deformed to eliminate headspace. This stretchable lid
material, however, typically is not puncture resistant and, hence, requires some
secondary protection to maximize quality control of the product.
It is a general object of this invention to provide an improved
method of filling and sealing a container with a product, and an associated
container.
Preferably, an extended package is provided in which the integrity of
the seal of the lid is preserved and the voids within the container that allow
product movement are eliminated.
Use of a diaphragm or flexible lid in addition to the seal to close a
container body preferably is avoided.
Reduction of seal area contamination while increasing value
impression also is desirable.
The fill volume of the container preferably should be less than the
initial container volume to thereby isolate the product from the seal area and
avoid seal area contamination.
In one aspect, the container may be a retortable container which
allows for shorter cooking time.
Objects and advantages of the invention will become apparent from
the detailed description and from the appended drawings in which like numbers
have been used to designate like parts in the several views.
SUMMARY OF THE INVENTION
In one aspect, the invention provides a method of filling and
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2038380
sealing a bi-stable container, subjected to a gaseous environment, with a product
comprising the steps of providing a semi-rigid container having a bi-stable,
unribbed bottom having a hoop member surrounding the side edges of the
container and movable between a first position, wherein said container bottom is
moved into a stable downwardly extended position, and a second position,
wherein said container bottom is moved into a stable inverted domed
configuration; placing the container bottom in its stable downwardly extended
position; charging the product into the container to a level having a volume less
than the container volume but equal to the filled volume with such level
defining a headspace opening; placing the container in a vacuum environment
chamber; sealing a generally flat lid to said container; removing the vacuum
environment from the container so as to return the container to atmospheric
pressure wherein hoop stress of said hoop member overcomes the bending stress
around said unribbed bottom such that the unribbed bottom of the container is
inverted into said stable inverted domed configuration thereby forcing the
product into close contact with the lid to reduce the headspace between the
product and the lid and wherein the lid remains in its generally flat
configuration.
In another aspect there is provided a method of filling and sealing a
bi-stable container, subjected to a gaseous environment, with a product
comprising the steps of:
providing a semi-rigid container having a bi-stable, unribbed
bottom having a hoop member surrounding the side edges of the container and
movable between a first position, wherein said container bottom is moved into a
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2038380
stable downwardly extended position, and a second position, wherein saidcontainer bottom is moved into a stable inverted domed configuration;
placing the container bottom in its stable downwardly extended
osition;
charging the product into the container to a level having a volume
less than the container volume but equal to the filled volume with such level
defining a headspace opening;
positioning a generally flat lid adjacent to a sealing surface and rim
section of said container;
placing the container in a vacuum environment chamber below a
sealing head;
mounting the sealing surface of said container within said vacuum
chamber along a leading edge of an anvil;
evacuating the gas within said vacuum chamber and container such
that said pressure of the headspace air within said container is lowered to that of
said vacuum chamber;
lowering said sealing head within said vacuum chamber when the
desired vacuum level is achieved such that the sealing head seals the lid to said
sealing surface of said container; and
removing said vacuum environment from said container so as to
return the container to atmospheric pressure wherein hoop stress of said hoop
member overcomes the bending stress around said unribbed bottom such that
said unribbed bottom of the container is inverted into said stable inverted domed
configuration thereby forcing the product into close contact with said lid to
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20~8380
reduce the headspace between said product and said lid and wherein said lidremains in its generally flat configuration.
In the invention also provides a bi-stable container, subjected to a
gaseous environment, holding a product, said container being manufactured by
the process comprising the steps of:
providing a semi-rigid container having a bi-stable, unribbed
bottom having a hoop member surrounding the side edges of the container and
movable between a first position, wherein said container bottom is moved into a
stable downwardly extended position, and a second position, wherein said
container is moved into a stable inverted domed configuration;
placing the container bottom in its stable downwardly extended
position;
charging the product into the container to a level having a volume
less than the container volume but equal to the filled volume with such level
defining a headspace opening;
placing the container in a vacuum environment chamber;
sealing a generally flat lid to said container; and
removing the vacuum environment from the container so as to
return the container to atmospheric pressure wherein hoop stress of said hoop
member overcomes the bending stress around said unribbed bottom such that
the unribbed bottom of the container is inverted into said stable inverted domed
configuration thereby forcing the product into close contact with the lid to reduce
the headspace between the product and said lid and wherein said lid remains in
its generally flat configuration.
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2038380
In another aspect, there is provided a bi-stable container, subjected
to a gaseous environment, holding a product, said container being manufactured
according to a method comprising the steps of:
providing a semi-rigid container having a bi-stable, unribbed
bottom having a hoop member surrounding the side edges of the container and
movable between a first position, wherein said container bottom is moved into a
stable downwardly extended position, and a second position, wherein said
container bottom is moved into a stable inverted domed configuration;
placing the container bottom in its stable downwardly extended
osition;
charging the product into the container to a level having a volume
less than the container volume but equal to the filled volume with such level
defining a headspace opening;
positioning a generally flat lid adjacent to a sealing surface and a rim
section of said container;
placing the container in a vacuum environment chamber below a
sealing head;
mounting the sealing surface of said container within said vacuum
chamber along a leading edge of an anvil;
evacuating the gas within said vacuum chamber and container such
that said pressure of the headspace gas within said container is lowered to that of
said vacuum chamber;
lowering said sealing head within said vacuum chamber when the
desired vacuum level is achieved such that the sealing head seals the lid to said
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2038380
sealing surface of said container; and
removing said vacuum environment from said container so as toreturn the container to atmospheric pressure wherein hoop stress of said hoop
member overcomes the bending stress around said unribbed bottom such that
said unribbed bottom of the container is inverted into said stable inverted domed
configuration thereby forcing the product into close contact with said lid to
reduce the headspace between said product and said lid and wherein said lid
remains in its generally flat configuration.
A still further aspect of the invention provides a method of filling
and sealing a semi-rigid bi-stable container, subjected to a gaseous environment,
with a product and having a mechanically bi-stable bottom movable between a
first position, wherein said container bottom is moved into a stable downwardly
extended position, and a second position, wherein said container bottom is
moved into a stable inverted domed configuration, and further having a hoop
member surrounding the side edges of the container, said method comprising
the steps of placing the container bottom formed of a semi-rigid material in said
stable downwardly extended position, charging the product into the container to
a level having a volume less than the container volume but equal to the filled
volume with such level defining a headspace opening; flushing out the
headspace gas with steam; sealing a generally flat lid to the container; allowing
the headspace to cool, and condensing the steam to water resulting in a vacuum
within the headspace; returning the container to atmospheric pressure wherein
hoop stress of said hoop member overcomes the bending stress around said
unribbed bottom such that the unribbed container bottom is inverted into said
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2038380
stable inverted domed configuration thereby forcing the product into closecontact with the lid to reduce the headspace between the product and the lid and
wherein the lid remains in its generally flat configuration.
The invention also provides a method of filling and sealing a bi-
stable container, subjected to a gaseous environment, with a product and having
a bottom deformable between stable upward and downward positions and
having a hoop member surrounding the side edges of the container, said method
comprising the steps of:
placing the container having an unribbed bottom upon an anvil;
charging the container with the unribbed bottom in its stable
downward position with a product to a level having a volume less than the
container volume but equal to the filled volume with such level defining a
headspace opening;
maintaining the unribbed bottom in its downward position with a
vacuum suction cup;
positioning a generally flat lid adjacent to a sealing surface;
placing the container in a position to be steam flushed;
flushing out the headspace gas with steam;
placing the container below a sealing head;
mounting the sealing surface of said container along a leading edge
of said anvil;
lowering said sealing head such that the sealing head seals the lid to
said sealing surface of said container;
allowing the headspace to cool, and condensing the steam to water
-3e-
2038380esulting in a vacuum within the headspace;maintaining the unribbed bottom of the base in its downward
position with a vacuum suction cup;
releasing the vacuum suction cup from the base of the container
and returning the container to atmospheric pressure wherein hoop stress of said
hoop member resists the bending stress around said unribbed bottom such that
the unribbed bottom is inverted to its stable upwardly extended position thereby
forcing the product into close contact with said lid to reduce the headspace
between said product and said lid and wherein said lid remains in its generally
flat configuration.
A still further aspect of the invention provides a container,
subjected to a gaseous environment, holding a product and having a bottom
deformable in shape between downward and upward stable positions and having
a hoop member surrounding the side edges of the container, said container being
manufactured by the process comprising the steps of:
placing the container having an unribbed bottom in said stable
downward position upon an anvil;
charging the container with its unribbed bottom in its downward
position with the product having a volume less than the container volume but
equal to the filled volume with such level defining a headspace opening;
maintaining the unribbed bottom in its downward position with a
vacuum suction cup;
positioning a generally flat lid adjacent to a sealing surface;
placing the container in a position to be steam flushed;
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2038380
flushing out the headspace gas with steam;sealing said lid to said container;
allowing the headspace to cool, and condensing the steam to water
resulting in a vacuum with the headspace;
maintaining the unribbed bottom of the base in its downward
position with a vacuum suction cup;
releasing the vacuum suction cup from the base of the container
and returning the container to atmospheric pressure wherein hoop stress of said
hoop member resists the bending stress around said unribbed bottom such that
the bottom of the container is inverted into its stable upwardly extended position
thereby forcing the product into close contact with the lid to thereby reduce the
headspace between the product and the lid and wherein the lid remains in its
generally flat configuration.
In general, then this invention relates to a method of filling and
sealing a package with a product, and more particularly to a method of producing
a sterilized package in which the integrity of the seal and the lid is preserved and
the voids within the container that allow product movement are eliminated.
The container is designed with a base having a deformable or drawable insert and
with the correct ratio of wall strength to the radius of curvature so that the
bottom is stable in either the up or down position. The whole container is made
of a semi-rigid material, and hence, the bottom is not a stretchable diaphragm.
The use of laminations of thermoplastic foil, thin aluminum or steel enables the
container to be puncture resistant and provides for considerable resistance to
damage in handling and transportation.
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4050~0-2060
PATENT 2 0 3~ 3 ~ ~
In cperation, the container is filled with the base
in i~s downward position so that the charging product ralls
belo~ ~he seal surface. Thus, there is sufficient headspace
to permit the lid placement without squeezina product onto the
seal surface. The edse of a top cut lid is then positioned
ad~acent to a rim section of the container. The filled
container and lid are then transferred into a vacuum chamber
with the sealing surface of the container being supported on
an anvil. The gas in the vacuum chamber is then evacuated.
In this position, a sealing head above the container is in a
raised position. This process lowers the pressure of the
headspace gas within the container to that of the chamber.
When the desired vacuum level is achieved the sealing head is
lowered and the lid is sealed to the container. Subsequent
thereto, the chamber is brought back to atmospheric pressure
such that the base is inverted thereby forcing the product to
move upwardly to fill the headspace or voids within the
container.
As such, this method to fill and seal a container
enables the fill volume to be less than the initial container
volume to thereby isolate the product from the seal area to
avoid seal area contamination. In addition, this process
eliminates the voids within the container which allow product
movement.
20:~8380
BRIEF DESCRIPTION OF THE DRAWI~GS
The following detailed description, given by wav of
example, but not intended to limit the invention solely to the
specific embodiments described, may best be understood in
conjunction with the accompanying drawings in which:
Figure 1 is a front perspective view of a preferred
embodiment of the container of this invention.
Fiqure 2 is a side cross-sectional view taken along
line 2-2 of Fig. l with the base of the container in its
downward position.
Figure 3 is a side cross-sectional view taken along
line 2-2 of Fig. 1 with the base of the container in its
intermediate position.
Figure 4 is a side cross-sectional view taken along
line 2-2 of Fig. 1 illustrating the base of the container in
its upward position.
Figures 5-9 illustrate a preferred method of filling
and sealing a deformable container.
Figures 10 and 11 illustrate a method for steam flushing.
DETAILED DESCRIPTION OF PREF~RRED EM~ODIMENT
- This invention relates to a method of filling and
sealing a package with a product, and more par~icularly, to a
method of producing an e~tended life package in which the
integrity of the seal and the lid is preserved and the voids
within the container that allow product movement are
eliminated. Referring now to Fig. 1, a preferred embodiment
of a container 10 is provided. The body 10 has a bottom 12
which has a flexible insert 14 substantially deformable in
_ 5 _
405060-206Q
2 0 3 8 3 8 0
ahape. Since the hoop stress provides for tension along the
cl cumference of the container ~ase, in the preferred
embodiment, the container can be ~bi-stable" in that it is
stationarv in either the up or down positions of the
container. The base includes a deformable hoop webbing 16
between the insert 14 and the side edges 18 of the container.
These riqid side edges 18 support an upper flange 20 which
extends outwardly therefrom. The upper flange 20 includes a
sealing surface 22 which terminates in a crimped raised rim
section 24.
As is best shown in Fig. 2, the ccntainer body is
capable of receiving and retaining a top cut lid 26 which is
sealed to the container in the grooves 27 formed between the
sealing surface 22 and the raised rim section 24. This lid is
preferably formed of a puncture-resistant plastic material,
but any material, including a nonplastic material, such as
reinforced paper, which is substantially puncture-resistant
may be utilized. As a force A (see Fig. 2), moves the base 12
upwardly, the outer rim or hoop member 16 of the base is
stretched. As is illustrated in Fig. 3, the bending at the
edges of the body induces stress to restore the body 10 to its
original shape in the intermediate position of the deformable
bottom. After a force A is applied to the container bottom,
the bottom is inverted forming an inverted U shape (see Fig.
4). This angle ~ is decreased as the hoop stress of the hoop
member 16 resists the bending stress around the base.
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203~380
A~ a result of this design, the bottom is stable i~
either the up or down position, and as such, the bottom is
bi-stable. Since the whole container is made of a semi-rigid
material, the bottom is not a stretchable diaphragm. The base
1 is thus held stable in either position by the hoop stress
of the outer diameter 16 of the base 12.
In another preferred embodiment of the deformable
container of this invention, the container body may have a
deformable bottom which is entirely deformable in shape. In
this configuration, the base does not include a hoop member,
such as 16 (see Fig. 1). The body of this preferred
embodiment also includes semi-rigid side members which support
an upper flange which extends outwardly from the side
surfaces. The upper flange includes a sealing surface which
terminates in the rim section. A force A applied to the
container base, moves the base upwardly thereby stretching the
outer rlm of the base. In the intermediate stage, the side
walls of the container are pushed outward as the base is
inverted. The bending at the edges induces stress to restore
the container to its original shape. When the base is in its
final upward position, the hoop stress along the side edges
resists this bending stress and holds the base stable in the
up position.
In these or other embodiments, the containers may be
manufactured with the base either up or down, provided the
hoop stress induced in the outer diameter of the base can
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203~380
esist the restoring stresses, and can hold the base stable in
the position opposite to the manufactured position.
A preferred method for filling and sealing these
deformable containers is shown in Figs. 5-9. Referring now to
Fig. 5, the sealing surface 22 of the container body 10 is
mounted on support arms 28 of an anvil 30. The cavity 32 of
container body lO is charged with a product 34 from a filler
36. This product charge is sufficiently fluid or malleable so
that it will not tend to assume any specific natural shape,
but however, will fill the void volume of the container with a
secured lid. In this configuration, the container is filled
with the insert 14 of the base 12 in its downwardly position.
After the product has been initially charged into the
container, there is still suf~icient headspace, however, to
permit lid placement without squeezing the top of the product
fill onto the sealing surface (see Fig. 6).
Referring now to Fig. 7, the filled container
supported on anvil 30 and lid are then transferred into a
vacuum chamber 38. When the container and lid are initially
transferred into the vacuum chamber, a sealing head 40 is
disposed in the vacuum chamber immediately above anvil 30 in
its raised position. In this position, the gas in the vacuum
chamber 38 is evacuated through multiple ports 42a, b and c.
Due to the force of the evacuation, an opening 44 is formed
between lid 26 and sealing sur~ace 22 of the container body
2038380
.0, and as ~ result thereof, the pressure of the headspace ~ir
within the container is lowered to that of the vacuum chamber.
When the desired vacuum le~el is achieved within the
chamber 38, and as such, gas has been exhausted throush ports
42a, b and c, the seal head 40 is lowered and the lid 26 is
sealed to the sealing surface ~2 of the container body 10, as
is shown in Fig. 8. Even though the preferred embodiment
herein discloses that the lid may be heat sealed to the
sealing surface 22 of container body 10, other methods of
sealing may be utilized. These include induction sealing,
spin welding, cold seal, ultrasonic sealing or seaming. The
edges 46 of the seal head 40 apply pressure to the outward
edges 48 of the continuous top lid 26 such that the outward
edges 48 are closely confined to the sealing surface 22 of
container body 10 (see Fig. 8). During this sealing process,
the vacuum is maintained.
As is illustrated in Fig. 9, the container is
removed from the vacuum chamber such that the container is
brought back to atmospheric pressure. As a result thereof,
the deformable insert 14 of base 12 is inverted upwardly,
thereby forcing the product 34 in the direction of arrow B to
fill the headspace and voids 50. The wet or dry products
within the container must be sufficiently mobile to move into
the voids. Since the product is forced into the voids S~ when
the container is brought back to atmospheric pressure, the
value impression of the product to the consumer is thereby
_ g _
2038380
_mproved. As a resu7 t thereof, ~uch a method of ~illing and
sealinq a deformable container enables the fill volume to be
less than the initial container volume to thereby isolate the
product from the seal area to avoid seal area contamination.
This process, however, also eliminates voids within the
container which allow product movement.
While the preferred embodiment of the present
invention has been described, it should be understood that
various changes, adaptations and modifications may be made
therein without departing from the spirit of the invention and
the scope of the appended claims. For instance, the force A,
as is shown in Figs. 2, 3, and 8 may be caused by either the
return to atmospheric pressure of the container after the
vacuum environment is terminated or by a mechanical push. In
ad~ition, preferably the container body is bi-stable, i.e.,
the container is stable with the deformable insert being in
either the up or down position. If, however, the container is
not bi-stable, such that the deformable bottom will remain in
the down position unless held up by a vacuum, or partial
vacuum, within the container, 2 worker will then be able to
recognize that a loss of sufficient vacuum occurred during
filling. As a result thereof, the product should be rejected.
Additionally, this method may be utilized for steam
flushing, as is shown in Figs. 10 and 11, which is an
important alternative for filling the container with a hot
product. Without steam flushing, the vacuum maintained during
-- 10 --
40506~-2060
~ 0 3 8 3 8 0
.he process would cause the hot product to boi~ lith this
steam flushin~ process, the evacuation of the pack may be
achieved by flushing out the headspace qas 5~ (see Fig. 10)
with steam 54 from a steam duct 56 just prior to sealing the
lid. The steam e~its the headspace through an extract duct
58. While the steam flushing is taking place, the lid 60 of
container 62 is held above the container 62 by a lid holding
device 64. As in the previous preferred embodiment, the
sealing sùrface 66 of the container is mounted on support arms
68 of an anvil 70. Additionally, a sealin~ head 74 is in its
raised position above the sealing surface of the container.
After the headspace gas is steam flushed, the
sealing head is lowered and the lid is sealed to the sealing
surface of the container body ~see Flg. 11). This steam will
then condense to water, on cooling, resulting in a vacuum
within the container headspace. As in Fig. 9, the container
is then subjected to atmospheric pressure to invert the
container bottom into its upward position thereby forcing the
product into close contact with the lid to thereby reduce the
headspace between the product and the lid.
With steam flushing, it is possible to utilize a
container that has a bottom which is stable only in the up
position. This base can be held down with a vacuum suction
cup during filling and sealing, then released to invert to its
original and stable position aided by the vacuum induced by
the steam flush. This container design, with its dome base
-- 11 --
405060-2060
PATENT
20~838Q
stable in the up position, could be used with a vacuum
chamber, but, in order to deform the bottom of the container
dcwnwardlv, a mechanical gripper could engage any suitable
attachment member extending from the container bottom.
It is intended that the appended claims be
interpreted as including the foreaoing as well as various
other such changes and modifications.
