Note: Descriptions are shown in the official language in which they were submitted.
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1 FIELD OF THE INVENTION
The present invention relates to a vacuum
packing method and an apparatus for practicing the same.
It is noted in this specification that the term of
"vacuum packing" means to pack contents in a bag by
reducing the pressure in the bag sufficiently lower than
the atmospheric pressure. The pressure in the bag may
be relatively high, for example in the order of a few or
several hundreds torr, depending upon the kind of .
10 contents.
DESCRIPTION OF THE PRIOR ART
There has been disclosed in Japanese Patent
Unexamined Publication No. 51-40291 a vacuum packing
method and an apparatus therefor in which after a mouth
or opening of a bag is temporarily or roughly sealed in
such a manner as to prevent the leakage of contents such
as cereal grains or the like, the bag thus sealed
temporarily is placed in a closed chamber covered with a
cover ember serving as a vacuum chamber-forming means,
and the interior of the closed chamber is evacuated and,
at the same time, the bag is shaped by a pressure plate,
and thereafter, the mouth of the bag is sealed com-
pletely in the closed chamber.
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1 However, according to the above vacuum packing
method) it is necessary for the mouth of the bag to be
subjected to the sealing step at twice. Furthermore, in
this vacuum packing apparatus, it is necessary to equip
a sealing machine for bag welding use which is capable
of being positioned in the closed chamber of a vacuum
chamber-forming device.
On the other hand, there has been disclosed in
Japanese Patent Unexamined Publication No. 58-193227 a
vacuum packing method and an apparatus therefor in which
after filling contents into a packing bag one end of
which is opened, a nozzle is inserted into the opening
of the packing bag so as to permit parts of the opening
around the inserted nozzle to be sealed, then the
interior of the bag is evacuated under an environment of
the atmospheric pressure, and the then remaining parts
of the opening which are brought into close contact with
each other are sealed by welding.
However, even according to this vacuum packing
method, it is necessary that the mouth or opening of the
bag is subjected to the sealing step at twice. In
addition, in the case of this vacuum packing method, it
is necessary to shift the nozzle away from the sealing
position at the time of the second sealing work.
Furthermore, in the case of this vacuum packing method,
there is a possibility that a part of the contents is
ucked into the nozzle when elements constituting the
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1 contents are relatively small in size. Moreover, in
this case, there i5 another possibility that a trace of
the shape of the nozzle is l~ft on the bag. Further, in
this vacuum packing apparatus, it is required to provide
the sealing machine with the vacuum suction nozzle.
Further, in Japanese Patent Unexamined
Publication Nc. 63-317430, a vacuum shaping apparatus is
disclosed in which a vacuum-packed article, formed by
vacuum-packing granular contents such as rice grains,
wheat grains, coffee beans or the like in advance making
use of a similar method to the vacuum packing method
disclosed in Japanese Patent Vnexamined Publication No.
58-193227, is placed in a closed chamber covered with a
cover member serving as a vacuum chamber-forming means,
the pressure in the closed chamber is reduced down to
the internal pressure of the packed article, and then
the packed article is given with pressure and oscilla-
tion due to a pressure holding plate so as to be shaped.
However, in the case of the similar method to
the vacuum packing method disclosed in Japanese Patent
Unexamined Publication No. 58-193227, suction or evacua-
tion by the nozzle is performed in the atmospheric
environment so that it is hard to avoid variation or
unevenness in the degree of vacuum in the packing bags.
Accordingly, the pressure in the closed chamber does not
always become e~ual to the internal pressure of the
packed article in some cases. Concerning the packed
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l articles the internal pressure of which is relatively
low, for example, the internal pressure is lower than
the pressure in the vacuum chamber, resulting in that it
is difficult to shape the article satisfactorily.
SUMMARY OF THE INVENTION
The present invention has been made in view of
the above-described points and an object thereof is to
provide a vacuum packing method which is capable of
enabling the vacuum-packed state to be maintained in the
atmospheric air even without sealing a bag member as by
welding after the evacuation suction is effected, and an
apparatus for practicing this method.
To this end, there is provided according to
the present invention a vacuum packing method for
packing contents in a reduced pressure, comprising the
steps of: after filling a predetermined quantity of the
contents into a packing bag, sealing a mouth or opening
portion of the packing bag in such a manner as to leave
an elongated non-linear communication passage between an
inner region of the bag in which the contents are filled
and an outside of the bag so as to form an intermediate
packed article; subjecting the intermediate packed
article to pressure reduction for degassing the inner
region in the intermediate packed article; and after the
pressure reduction and degassing step, restoring an
atmosphere around the packed article to the atmospheric
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1 pressure so as to close the communication passage.
In accordance with the vacuum packing method
of the present invention, since the intermediate packed
article is formed by sealing the mouth portion of the
packing bag in such a manner as to leave the elongated
non-linear communication passage between the inner
region of in the bag in which the contents are filled
and the out ide of the bag, it is possible to let air
out of (degas) the intermediate packed article through
the elongated non-linear communication passage by
subjecting the intermediate packed article to pressure
reduction. Further, according to the vacuum packing
method of the invention, the inner region of the bag in
which the contents are filled is communicated with the
outside of the bag only through the elongated non-linear
communication passage defined by a wall portion having
the flexibility attributable to the bag itself, so that
the communication passage defined by the flexible wall
is squashed to be closed simply by restoring the atmos-
phere around the packed article to the atmosphericpressure after the degassing. The communication passage
thus squashed serves as a check valve in practice so
that the sealing is completed automatically. It is
preferred that the restoring to the atmospheric pressure
is effected rapidly. The term of "rapidly" means,
herein, that the restoring is effected sufficiently more
quickly than the internal pressure of the packed article
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l becomes higher through the communication passage. In
this case, it is possible to close the communication
passage without breaking or affecting the vacuum or
reduced-pressure state in the packed article in
practice. In the case of this method, if the communi-
cation passages of the respective packing bags are
formed to have the same configuration and size, it is
possible to positively obtain the packed articles of a
substantially uniform degree of vacuum or reduced
pressure by keeping the degassing condition constant.
In a vacuum packing method according to a
preferred embodiment of the present invention, the
communication passage is formed into a zigzag shape in
the intermediate packed article forming step. Further,
in a vacuum packing method according to another pre-
ferred embodiment of the invention, the communication
passage is formed into a mazy shape in the intermediate
packed article forming step. The open ends of the
communication passage may be formed at side ends of the
bag or at a central or intermediate position(s) between
the side ends.
In a vacuum packing method according to a
preferred embodiment of the invention, the degree of
expansion of the packing bag of the intermediate packed
article is controlled to be not greater than a pre-
determined level by a wall of a vacuum chamber, for
example, in the pressure reduction and degassing step.
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1 In this case, there is no possibility that the bag is
expanded in excess to be burst or ruptured even if a
large differential pressure is applied between the
inside and outside of the bag.
In a vacuum packing method according to a
preferred embodiment of the invention, the intermediate
packed article is pressed from outside during at least a
part of a period of the pressure reduction and degassing
step. In this case, pressing of the intermediate packed
article makes it possible not only to reduce the time
required for the pressure reduction and degassing but
also to perform the shaping of the packed article.
In a vacuum packing method according to a
preferred embodiment of the invention, the intermediate
packed article is vibrated or oscillated during at least
a part of a period of the pressure reduction and degas-
sing step. In this case, giving vibration or oscilla-
tion to the intermediate packed article makes it
possible not only to perform the shaping of the packed
article but also to reduce the time required for the
pressure reduction and degassing.
In a vacuum packing method according to a
preferred embodiment of the invention, the intermediate
packed article i5 pressed from an outside thereof while
being vibrated or oscillated during at least a part of a
period of the pressure reduction and degassing step. In
this case, giving vibration or oscillation to and
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1 pressing of the intermediate packed article make it
possible not only to reduce the time required for the
pressure reduction and degassing but also to perform the
shaping of the packed article.
A vacuum packing method according to a
preferred embodiment of the invention further comprises
the step of closing the communication passage by an
additional sealing after the step of exposing to the
air, i.e. restoring the atmosphere to the atmospheric
pressure. The term "additional sealing" referred to in
this case means the simple one such as the bonding with
a bonding agent or the adhering of a sheet such as
paper, for example. However, if desired, the communica-
tion passage may be additionally sealed as by heat
welding mean~ at least at a portion of the aperture or
opening thereof. In the case of this embodiment, the
vacuum packed state can be prevented from being broken
even if it is handled very roughly during the trans-
portation or the like.
Further, there is provided according to the
present invention a vacuum packing apparatus for
packing, in a reduced pressure, contents of an inter-
mediate packed article formed by sealing a mouth or
opening portion of a packing bag in which the contents
are filled in such a manner as to leave an elongated
non-linear communication passage between an inner region
of the bag in which the contents are filled and an
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1 outside of the bag, which apparatus comprises a cradle
plate on which the intermediate packed article is to be
placed, vibration means for vibrating or oscillating the
cradle plate on which the intermediate packed article is
placed so as to give vibration or oscillation to the
intermediate packed article, a chamber-forming means
having a concave portion of a capacity greater than a
volume of the intermediate packed article, a periphery
of an opening end of the concave portion being brought
10 into air-tight contact with the cradle plate so as to '`!
form an openable closed chamber in cooperation with the
cradle plate, pressure reduction means for reducing a --
pressure in the closed chamber, and air supply means for
supplying air rapidly into the closed chamber, and
wherein the intermediate packed article placed on the
cradle plate is given with vibration or oscillation by
the vibration or oscillation means within the closed
chamber and, at the same time, the pressure in the
closed chamber i5 reduced by the pressure reduction
2~ means so as to reduce a pressure in the inner region of
the intermediate packed article through the communica-
tion passage thereof, and thereafter, the pressure in
the closed chamber i5 restored to the atmospheric
pressure rapidly by the air supply means. In this case,
there is no necessity to equip a sealing machine in the
vacuum chamber-forming means because the additional
sealing is not necessarily required.
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1 In addition, there is provided according to
the present invention a vacuum packing apparatus for
packing, in a reduced pressure, contents of an inter-
mediate packed article formed by sealing a mouth portion
of a packing bag in which the contents are filled in
such a manner as to leave an elongated non-linear
communication passage between an inner region of the bag
in which the contents are filled and the outside of the
bag, which apparatus comprises a cradle plate on which
the intermediate packed article is to be placed, vibra-
tion means for vibrating or oscillating the cradle plate
on which the intermediate packed article is placed so as
to give vibration or oscillation to the intermediate
packed article, a chamber-forming means having a concave
portion of a capacity greater than a volume of the
intermediate packed article, a periphery of an opening
end of the concave portion being brought into air-tight
contact with the cradle plate so as to form an openable
closed chamber in cooperation with the cradle plate,
pressure means connected to the chamber-forming means
for s0rving to press a top surface of the intermediate
packed article placed on the cradle plate, pressure
reduction means for reducing a pressure in the closed
chamber and air supply means for supplying air rapidly
into the closed chamber, and wherein the intermediate
packed article placed on the cradle plate is given with
vibration or oscillation by the vibration or oscillation
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1 means within the closed chamber while being pres~ed by
the pressure means and, at the same time, the prea~ure
in the closed chamber is reduced by the pressure reduc-
tion means so as to reduce a pressure in the inner
region of the intermediate packed article through the
communication passage thereof, and thereafter, the
pressure in the closed chamber is restored to the ~.
atmospheric pressure rapidly by the air supply means.
The foregoing and other objects, features as
well as advantages of the invention will be made clearer
from description of preferred embodiments of the inven-
tion referring to attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures lA to lC are explanatory views of
intermediate packed articles, a mouth or opening of a
bag of each article being sealed by a welding sealing
machine known per se in accordance with a vacuum packing
method of a preferred embodiment of the present inven-
tion in such a manner that an elongated non-linear
communication passage is left;
Figure 2 is a front sectional view of a vacuum
packing apparatus for practicing a vacuum packing method
according to a preferred embodiment of the invention;
Figure 3 is a front sectional view of the
apparatus of Figure 2 but showing an operating state
different rom that of Figure 2;
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1 Figure 4 is a front sectional Vi2W of a vacuum
packing apparatus for practicing a vacuum packing method
according to another preferred embodiment of the
invention;
Figure 5 is a front sectional view of a vacuum
packing apparatus for practicing a vacuum packing method
according to still another preferred embodiment of the
invention;
Figure 6 is a front sectional view of the
apparatus of Figure 5 but showing an operating state
different from that of Figure 5; and
Figures 7 and 8 are views for explanation of
vacuum packing methods according to further preferred
embodiments of the invention in which a packed article
is subjected to an additional sealing work.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
Description will now be given of preferred
embodiments of the present invention with reference to
the drawings.
Contents 1 are first filled or stuffed into a
packing bag 2 and, then, a mouth or opening portion 6 of
the packing bag 2 i9 subjected to the sealing work along
lines 7, 8 in such a manner as to permit an elongated
non-linear communication passage 5 to be left between a
region 3 in the bag 2 in which the contents 1 are filled
and an outside 4 of the bag 2, thereby forming an inter-
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1 mediate packed article 9 shown in Figure lA, for
example.
The contents 1 consist of cereal grains such
as rice grains, wheat grains, coffee beans or the like,
for example. The contents 1 may be other granular
substance than the cereal grain or a substance of
similar shape such a~ tea. However, the contents are
not limited to these substances but may be any goods so
far as it is suitable for the vacuum packing and can be
received in the bag 2.
The packin~ bag 2 is typically made of a
thermoplastic film or sheet, and however, it may be made
of other material so far as it is a flexible sheet
material and fits for the sealing work. More spe-
cifically and typically, the film may be made fromlaminated layers, one of which comprises a gas barrier
resin layer of material such as polyamide resin,
saponificated ethylene-vinyl acetate copolymer, thermo-
plastic polyester or polyvinylidene chloride, and the
other of which is a transparent polyolefin resin layer
of material such as low-density polyethylene, ethylene-
vinyl acetate copolymer or polypropylene, as described
in Japanese Patent Examined Publication No. 57-40781.
The size of the bag 2, the thickness of the
film constituting the bag 2 and the like are so selected
as to be conformed to the volume, weight and the like of
the contents 1 to be received.
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1 The communication passage 5 is formed to
extend long (length) and slenderly or narrow (width) so
that when the pressure at the outside 4 of the bag 2
becomes higher than the pressure at the inside 3
thereof, communication between the inside and outside 3
and 4 of the bag 2 is interrupted in a short time due to
deformation of a portion of the film constituting a
peripheral wall lO of the communication passage 5. The
width and length of the communication passage 5 are
respectively sufficiently wide and short enough to make
it possible to deflate a gas from the inside 3 of the
bag 2 through the communication passage 5 within a short
time (within about ten seconds, for example) so as to
substantially equalize the pressures at the inside and
outside 3 and 4 of the bag 2 to each other when the
pressure at the inside 3 of the bag 2 is higher than the
pressure at the outside 4 of the bag 2 beyond a certain
degree (beyond several hundred torr, for example) as
described later in detail. The width and length of the
communication passage 5 are selected in accordance with
the bag size, kind of material of the film forming the
bag 2, thickness of the film and the like. In the case
of the example shown in Figure lA, the communication
passage 5 is defined between sealing lines 7 and 8 to
extend from a small opening 11 to small openings 12, 13
in a zigzag way. The width of the communication passage
5 may vary depending upon the longitudinal position
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1 thereof. In such case, it is preferred to make it easy
to close the passage at a narrow portion serving as a
bottle neck. The apertures 11, 13 may be formed at
intermediate regions, instead of side ends, as shown in
Fig. lC.
Since a sealing operation effected on a bag of
a thermoplastic film using the heat or thermal welding
as indicated by the sealing lines 7, 8 and a sealing
device for carrying out such sealing operation per se is
well known, detailed explanation thereof will be
omitted. The small openings or apertures 11, 13 can be
formed, for example, by placing a thermally passive or
non-operative material such as glass fibers in the form
of a tape at each of the positions for the apertures 11,
13 before thermal welding operation to form the sealing
lines 7, 8. Such provision of glass fibers allows to
form the apertures 11, 13 when the sealing lines 7, 8
has been formed. It is noted that any other device or
method is available as well so far as it is capable of
providing the similar sealing lines and apertures.
This type of bags, having seal lines with
small apertures left, per se are known for example in
Japanese Patent Examined Publication No. 57-40781 for
packing the contents such as mushroom which generate a
gas such as carbon dioxide, where there i5 a possibility
that the gas is accumulated in the packing bag to cause
the swelling and rupture of the bag provided that the
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1 sealing is so effected as to make airtight completely
the interior of the bag. In this known sealing tech-
nique, therefore, such possibility can be avoided by
discharging the gas generate in the bag through an
elongated communication passage. In this respect, the
present invention differs from thi~ known technique in
t~rms of the manner of using the communication passage.
In place of the zigzag one shown in Figure lA,
the communication passage may be a mazy one 14 or 15 as
shown in Figure ls or lC, for example. In the case of
an intermediate packed article 24 shown in Figure lB,
sealing lines 16 and 17 themselves are straight lines so
that the communication passage 14 leads from a gap or a
small opening or aperture 11 defined between one end of
the sealing line 17 and the peripheral wall of the mouth
or opening portion 6 of the bag 2 to another gap or a
small opening or aperture 13 defined between one end of
the sealing line 16 and the peripheral wall of the mouth
or opening portion 6 of the bag 2 through a rectilinear
intermediate passage 18. In the case of an intermediate
packed article 25 shown in Figure lC as well, sealing
lines 19 and 20 per se are straight lines. However, the
sealing line 19 is divided into a plurality of segments
l9a, l9b and l9c by intermediate gaps or apertures 21a
and 21b, while the sealing line 20 is divided into a
plurality of segments 20a and 20b by an intermediate gap
or aperture 22. In consequence, the communication
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1 passage 15 consists of a first communication passage
portion 15a leading from the gap 22 to the gap 21a
through an intermediate passage portion 23a and a second
communication passage portion 15b leading from the gap
22 to the gap 21b through an intermediate passage por-
tion 23b. One of the apertures 21a, 21b may be omitted,
i.e. sealed. Such being the case, the aperture 22 will
be offset from the center to allow the associated
passage 23a or 23b sufficiently long.
Next, description will be given of the process
of letting air out of the inside of the intermediate
packed article 9 shown in Figure lA, for example, with
reference to Figures 2 and 3.
Reference numeral 31 denotes a plate pedestal
or base fixed to a frame (not shown). A cover member 33
serving as chamber-forming means which cooperates with
the pedestal 31 to form a closed chamber 32 is connected
to the pedestal 31 through a hinge element 34 so as to
be able to rotate in the directions A and B with respect
to the pedestal 31. The hinge element 32, however, can
be dispensed with. When the cover member 33 is rotated
in the direction B and put on the pedestal 31 as shown
in the drawing, a peripheral wall end face 35 of an
opening portion of a concave portion 33a of the cover
member 33 is brought into airtight contact with an upper
~urface 36 of the pedestal 31. If desired, either of
the airtight contact surfaces 35 and 36 may be provided
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1 with a proper sealing means such as a seal ring.
Although the height C of the cover member 33 is so
selected as to be suitable for the degassing operation
to be described later, the cover member 33 may be
con~tructed to have a changeable or variable height C.
An oscillating or vibrating plate 38 serving
as cradle plate is placed horizontally on the pedestal
31 through an air bag 37. The cradle plate 38 may be
formed in the upper surface thereof with a concave
portion of a prescribed form suited to the form into
which the lower part of the packed article 9 is to be
shaped, in place of a flat surface. The air bag 37 is
fixed to the pedestal 31 at the lower end hereof and to
the oscillating plate 38 at the upper end thereof in
such a manner that it is made to expand in the direction
D when the pressure in the closed chamber 32 is lowered
and to contract in the direction E when the pressure in
the closed chamber 32 is increased or when the inter-
mediate packed article 9 or the like is put on the
oscillating plate 38. The quantity of air in the air
bag 37 may be kept constant or adjustable. An oscilla-
tion or vibration generator or generating device 39
serving to oscillate upon receiving energy from the
power suppl~ (not shown), for example, is fixed to the
oscillating plate 38 so that, when the oscillation
generator 39 is made to oscillate, the oscillating plate
38 fixed thereto is caused to oscillate in the hori-
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1 zontal and/or vertical plane, for example.
A pressure plate 41 is fixed to the inner wall
of the cover member 33 through elastic members 40 in
such a manner as to be opposed to the oscillating plate
38 with space 42 left therebetween when the cover member
33 is brought into a closed chamber-forming position
thereof as shown in the drawing. The distance F between
a lower surface 43 of the pressure plate 41 and an upper
surface 44 of the oscillating plate 38 is greater than
the thickness G of the intermediate packed article 9
under the atmospheric pressure.
Reference numeral 45 denotes a evacuating or
exhaust device such as a vacuum pump. The evacuating
device 45 serves to reduce the pressure in the closed
chamber 32 through a pipe 46.
In case of performing the degassing by a
degassing apparatus 47 constructed as described above,
the cover member 33 is first opened in the direction A
through the medium of a handle (not shown), for example,
so as to permit the intermediate packed article 9 to be
put on the oscillating plate 38, and then, the energy is
supplied to the oscillation generator 39 to cause the
oscillation plate 38 to oscillate. At this time, since
the intermediate packed article 9 on the oscillation
plate 38 is also made to oscillate together with the
oscillation plate 38, even if the height of the inter-
mediate packed article 9 is not uniform exceedingly at
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1 first as indicated by an imaginary line in Figure 2, the
contents are moved due to oscillation so that the non-
uniformity of height can be reduced as indicated by a
solid line in Figure 2, for example, thereby enabling
the intermediate packed article 9 to be shaped to a
satisfactory degree or, in some cases, almost com-
pletely.
Then, if desired, the cover member 33 is
rotated in the direction B after once interrupting the
oscillation due to the oscillation generator 39, so as
to form the closed chamber 32 as shown in Figure 2. At
this time, the space 48 is left between the top portion
of the shaped intermediate packed article 9 and the
lower surface 43 of the pressure plate 41. When the
height C of the cover member 33 is sufficiently high or
when the intermediate packed article 9 is freed from
over little suffered from the nonuniformity of height,
the oscillation or vibration plate 38 may be started to
be oscillated or vibrated after the cover member 33 is
closed.
Then, as the evacuation device 45 is made to
operate, the pressure in the closed chamber 32 is
reduced rapidly so that the bag 2 of the intermediate
packed article 9 is made to expand due to the pressure
difference between the inside and outside of the bag 2
as shown in Figure 3. On the other hand, since the
inside and outside of the bag 2 are communicated with
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1 each other through the elongated communication passage
5, the air in the bag 2 is discharged into the closed
chamber 32 through the communication passage 5, thereby
performing the degassing of the stuffed or filled area 3
of the intermediate packed article 9. Further, at this
time, the air bag 37 is also caused to expand gradually
to push up the oscillating plate 38 in the direction D
so that the packed article 9 is pressed against the
pressure plate 41. This pressing promotes the degassing
of the packed article 9. During the evacuation and
degassing, since the oscillation generator 39 continues
to operate, the shaping function is continued due to the
oscillation of the oscillating plate 38.
After a predetermined time has elapsed in
accordance with various characteristics of the inter-
mediate packed article 9, as the oscillation generator
39 is stopped to operate and a valve ~not shown) for a
branch pipe (not shown) of a pipe 46, for example, is
opened to make the air flow into the closed chamber 32,
the pressure in the chamber 32 constituting an atmos-
phere around the packed article 9 is increased very
rapidly to become higher than the internal pressure of
the packed article 9, resulting in that tAe elongated
communication passage 5 of the packed article 9 is
squashed to be closed abruptly so as to serve as a check
valve in practice. In a vacuum packed article 49 thus
completed, since the pressure at the inside of the
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1 packing bag 2 can be maintained lower than the pressure
at the outside thereof (usually the atmospheric pres-
sure), the vacuum packed article 49 can hold its vacuum
shaped state or form permanently. With the increase of
the pressure in the chamber 32, the air bag 37 is
brought back again to its contracted state shown in
figure 2. After the pressure in the chamber 32 is
restored to the atmospheric pressure, the cover member
33 is opened in the direction A through the handle (not
shown) so that the vacuum packed article 49 is taken
out.
Not only the size and form of the cover member
33 and the size of the air bag 37 but also the amplitude
and frequency of oscillation of the oscillation gene-
rator 39, the rate of exhaust by the pump 45 and thelike are selected to be their respective predetermined
values depending on the size and kind of the packed
article 9, 49. It is of course possible as well that
the oscillation generator 39, pump 45 and the like are
so constructed as to be able to adjust these parameters.
By the way, before the degassing, the inside
and outside of the intermediate packed article 9 are
kept at the atmospheric pressure, so that the contents 1
in the packing bag 2 can flow freely in practice.
Therefore, it is also possible to shape the intermediate
packed article 9 manually after putting the same on the
plate 38. In this case, the oscillation generator 39
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1 may be dispensed with, and the oscillating plate 38
serves simply as the support and pressure plate.
However, in order to sufficiently reduce the pressure in
the vacuum packed article 49 in a short time, it is
preferred as described later to oscillate or vibrate the
bag 9 through the oscillating plate 38 even if the
shaping is not needed.
Next, description will be given of a modified
vacuum packing and shaping apparatus (referred to as
"vacuum shaping apparatus" hereinafter) 51 used for
practicing the vacuum shaping method according to a
preferred embodiment of the present invention with
reference to Figure 4. In the vacuum shaping apparatus
51, the same or similar components as those of the
apparatus 47 shown in Figures 2 and 3 are designated by
the same reference numerals.
In the vacuum shaping apparatus 51, reference
numeral 52 denotes a cylinder device actuated by
hydraulic or pneumatic pressure. The cylinder device 52
is fixed at cylinder main body portions 53 thereof to
the cover member 33. Piston rod portions 54 of the
cylinder device 52 penetrate through holes 55 formed in
the cover member 33 in such a manner as to be slidable
in the directions D and E with respect to the cover
member 33. A pressure plate 56 is fixed to projected
ands of the piston rod portions 54 so that, when the
piston rod portions 54 of the cylinder device 52 are
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1 made to stretch in the direction E by means of a drivinq
device inot shown), the pressure plate 56 acts to press
the intermediate packed article 9 put on the oscillation
plate 38, thereby effecting he degassing of the inter-
mediate packed article 9. In case that the pressure inthe chamber 32 is reduced, it is pre~erred to apply by
the cylinder device 52 a force which has a magnitude at
which the expansive force of the bag 2 of the packed
article 9 in the direction D and the pressing force of
the cylinder device 52 acting in the direction E are
balanced. This is because, if the pressing force of the
cylinder device 52 is too large, the bag 2 of the packed
article 9 is prevented from expanding in excess to
thereby hinder the contents 1 in the bag 2 from being
given with oscillation. In consequence, the cylinder
device 52 fulfills the same function as that the the air
bag 37 of the apparatus 47. However, since the cylinder
device 52 can be actuated independently whether the
pressure in the chamber 32 is reduced or not, it becomes
possible, as the degassing of the bag 2 proceeds to make
the bag 2 contract, to shape the intermediate packed
article 9 without manually not only at the atmospheric
pressure but also at reduced pressure. Further, it is
also possible to change the operating conditions such as
the length of extension stroke, pressing force and the
like of the cylinder device 52 in accordance with the
size, kind and the like of the intermediate packed
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. . ~ . .. . .. .
203~2~
l article 9. It is common to the apparatuses 51 and 47
that the intermediate packed article 9 is pressed by the
pressure plate and the oscillating plate, and however,
in the case of the apparatus 51, it is not the oscillat-
ing plate but the pressure plate 56 to be moved in thedirections E and D. Reference numeral 57 denotes an
oscillation generator having the same function as that
of the oscillation generator 39. In the apparatus 51,
however, there is provided no air bag 37 so that the
oscillation generator 57 can be attached to the lower
surface of the oscillating plate 38 over a wide range.
Reference numeral 58 denote~ an elastic or resilient
member serving to support he oscillating plate 38 while
permitting the plate 38 to oscillate with respect to the
pedestal 31.
It is evident that the apparatus 51 can be
used for the vacuum packing and shaping of the inter-
mediate packed article 9 in the same manner as the
apparatus 47 shown in Figures 2 and 3 and, therefore,
description of the operation thereof is omitted.
Next, description will be given of another
modified vacuum packing and shaping apparatus (referred
to as "vacuum shaping apparatus" hereinafter) 61 used
for practicing the vacuum shaping method according to a
preferred embodiment of the present invention with
reference to Figures 5 and 6. In the vacuum shaping
apparatus 61, the same or similar components as those of
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. .
. , . . : . - .
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2 :3 3 ~
1 the apparatus 51 shown in Figure 4 are designated by the
same reference numerals.
In the vacuum shaping apparatus 61, the
cylinder device 52 of the apparatus 51 is dispensed with
and the shaping of the packed article 9 is performed by
the oscillation of the oscillating plate 38. If
desired, the packed article 9 may be shaped manually
beforehand as mentioned before. Further, in this
apparatus 61, the height of the elastic support portion
58 and the height C of the cover member 33 are selected
to be their respective predetermined values for the
purpose of preventing the packing bag 2 by a top wall
portion 33b of the cover member 33 from being expanded
in excess to be burst or ruptured owing to the pressure
reduction in the closed chamber 32.
It is evident that the apparatus 61 can be
used for the vacuum packing and shaping of the inter-
mediate packed article 9 in the same manner as the
apparatus 47 shown in Figures 2 and 3 and the apparatus
51 shown in Figure 4 and, therefore, description of the
operation thereof is omitted.
Description will now be given below of
examples of the vacuum packing and shaping performed by
making use of the vacuum packing and shaping apparatus
47 shown in Figure 4.
FXAYPL~S
The cover member 33 had a concave portion 33a
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2 ~ ,J~ ~ ~ ? S
1 of the size which enabled the closed chamber 32 to have
the volume of 30 liters, and the vacuum or exhaust pump
45 had the capacity of enabling the pressure in the
closed chamber 32 to be reduced from 760 torr to 160
torr in five seconds. The air cylinders 52 serving as
the pressure devices had the pressing force of 210 kgf
at the maximum in all. 3 kg of polished rice grains
were received as the contents in the packing bag 2 made
from laminated film of polyamide resin layer (20 ~m) and
low density polyethylene layer (80 ~m). The inter-
mediate packed article 9 similar to that shown Figure lC
but the aperture 21b being sealed (closed) was made by
the sealing machine known per se. The communication
passage 23a was about 6 mm in width at the narrowest
portion thereof and about 8 cm in length from the
aperture 22 (offset from the center as described before)
to the apertu~e 21a.
Results of the vacuum packing and shaping
effected by the apparatus 51 shown in Figure 4 are shown
in Table 1 below.As understood from Example 1, in case
of exhausting at the aforementioned exhaust rate while
operating the pressure devices 52 and the oscillation
plate 38 concurrently, the pressure in the packed
article 49 after the completion of the shaping was 230
torr and the shaped state of the packed article 49 was
good as well. Accordingly, there is no possibility,
differently from the case of bad shaping, that the bag 2
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1 Table 1
.
Pressure o 11 Pressure
Example of vacuum Pressure scl a- of vacuum Shaped
No. in closed device 52 tion after state
chamber shaping
1 160 torr Maximum Full time 230 torr Good
power use use
160 torr Maximum Unuse 650 torr Bad
power use
_
3 160 torr Maximum two 270 torrBad
_ power use seconds
4 160 torr Unuse Full time Bag
use burst
160 torr 100 kgf Full time 700 torr Bad
is broken during the circulation or distribution of the
packed article 49 as commercial goods through a trade
market.
In case of effecting the vacuum shaping
without oscillating the oscillation plate 38 as seen in
Example 2, the pressure in the packed article 49 after
the shaping was 650 torr which is not so low and the
shaped state thereof was also bad. It is proved from
this fact that the oscillation is effective for the
shaping. Further, it is proved as well that the
pressure in the packed article 49 after the shaping
greatly depends on the presence of oscillation when the
contents 1 consist of granular one such as polished rice
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. . . :
. ...... ~ - . , ~ -. .
~3~33~
1 grains. On the other hand, in case of operating the
oscillation plate 38 only for initial two seconds of the
5-second evacuation time as seen in Example 3, although
the pressure in the packed article 49 was sufficiently
lowered to assure the vacuum packing completely, the
shaped state was bad.
To the contrary, in case of keeping the
pressure device 52 inoperative as seen in Example 4, the
expansion of the bag 2 could not be controlled within
the predetermined range so that the bag 2 was expanded
in excess to be burst or ruptured. It goes without
saying that different result can be obtained provided
that the expansion of the bag 2 is controlled in the
manner described in connection with the apparatus 61
shown in Figure 6, for example. On the other hand, in
case of setting the pressing force of the pressure
devices 52 as small as 100 kgf or so, the pressure in
the packed article 49 was 700 torr which was not sub-
stantially lowered and the shaped state was also bad,
and however, the bag 2 was prevented from being burst.
~ he examples described above were limited to
cases where the capacity and working time of the vacuum
pump 45 are fixed. Therefore, by adopting at least one
of the measures including to lengthen the evacuation
time while maintaining or decreasing the exhaust rate or
speed of the vacuum pump 45 and to increase the degree
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2 Q ~ 6
1 of vacuum in the closed chamber 32 by improving the
capacity of the vacuum pump 45, it will be possible to
perform the vacuum packing even if the pressure device
52 and the oscillation device 3~, 57 are not used.
Furthermore, if the manual shaping is performed before-
hand, the oscillation generator 39, 57 may not be used.
In addition, it is preferred that the volume
of the closed chamber 32, oscillation energy of the
oscillating plate 38, evacuating speed and the like can
be adjusted in accordance with the size, kind and the
like of the packing bag 2.
The vibrating, evacuating and/or pressing ope-
rations described above may be automatically controlled
by a control mechanism (not shown).
A product finished through the above vacuum
packing and shaping can maintain the vacuum packed and
shaped state thereof as it is under the normal handling
condition. In order to make it possible to maintain the
vacuum packed and shaped state even if given with an
excessive shock during the transportation or the like,
an additional sealing may be further performed for
completely closing the fine gap, such as the apertures
13, 21a, 21b, of the vacuum packed and shaped article
described above. It is sufficient for the additional
sealing to close the fine gap (corresponding to the
portion designated by reference numeral 13 in Figure lA,
for example) of the communication passage 5 only at
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. . :, : . ;......................... .: -- - -
-- ~ ~ .. . .. . .
.
2 ~ 3 ~ J ~
1 portions designated by reference numeral 70 as illust-
rated in Figures 7 and 8, for example. The additional
sealing means can include not only the heat or thermal
welding by the sealing machine but also any simple means
such as the appl.cation of a quick dry bonding agent or
the like and the adhering of a sheet piece so far as
being able to close the fine gap at the opening portion
of the communication passage 5.
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