U.S. patent number 3,832,824 [Application Number 05/375,300] was granted by the patent office on 1974-09-03 for apparatus and method for evacuating packages.
This patent grant is currently assigned to W. R. Grace & Co.. Invention is credited to William E. Burrell.
United States Patent |
3,832,824 |
Burrell |
September 3, 1974 |
APPARATUS AND METHOD FOR EVACUATING PACKAGES
Abstract
A filled flexible receptacle such as a thermoplastic bag
containing a food product is evacuated by placing the filled
portion of the bag in a first vacuum chamber; extending the neck of
the bag into a second and adjacent chamber; evacuating the first
chamber thereby causing the bag to balloon outwardly away from the
product; and, while the first chamber is being evacuated,
evacuating the second chamber and, consequently, evacuating the
interior of the ballooned bag; thereafter, when evacuation of the
bag is complete, elevating the pressure in the first chamber to
collapse the bag firmly around the product and immediately closing
the bag thereby making an evacuated package.
Inventors: |
Burrell; William E. (Duncan,
SC) |
Assignee: |
W. R. Grace & Co. (Duncan,
SC)
|
Family
ID: |
23480318 |
Appl.
No.: |
05/375,300 |
Filed: |
June 29, 1973 |
Current U.S.
Class: |
53/417; 53/86;
53/434; 53/479; 53/512 |
Current CPC
Class: |
B65B
31/024 (20130101) |
Current International
Class: |
B65B
31/02 (20060101); B65b 031/02 () |
Field of
Search: |
;53/22B,112B,79,86 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3714754 |
February 1973 |
Holcombe et al. |
|
Primary Examiner: McGehee; Travis S.
Attorney, Agent or Firm: Toney; John J. Lee, Jr.; William
D.
Claims
I claim:
1. A process of evacuating and closing flexible, impervious
receptacles such as pouches, bags and the like which have at least
one opening and contain at least one product comprising the steps
of:
a. confining the product containing portion of said receptacle with
a first region;
b. confining a portion of the receptacle which contains said
opening in a second region so that the interior of said receptacle
is in communication with said second region through said
opening;
c. reducing the pressure within said first region thereby causing
at least a part of said receptacle to move outwardly away from
contact with said product; and, subsequently,
d. reducing the pressure within said second region and consequently
evacuating the interior of said receptacle;
e. elevating the pressure in said first region to cause the
receptacle to move back into contact with said product; and,
thereafter,
f. closing said opening thereby making an evacuated, sealed,
package.
2. The method of claim 1 wherein the reduction in pressure in the
second chamber continues until the pressure in the second region is
lower than that in the first so that the receptacle has begun to
move back against said product before the pressure in the first
chamber is elevated.
3. The method of claim 1 wherein said regions are divided by a wall
having an aperture therein and the portion of the receptacle having
said opening is extended through said aperture.
4. The method of claim 1 wherein said receptacle is a thermoplastic
bag having a neck and a mouth which is the single opening to said
bag and including the steps of:
i. placing said bag's mouth and a portion of said bag's neck within
said second region while the product containing portion of the bag
remains in the first region; and, after the bag's interior has been
evacuated and pressure has been elevated in the first region,
ii. closing said opening by applying a metal clip to the neck of
said bag.
5. The method of claim 1 wherein said bag opening is closed by heat
sealing the neck walls together.
6. In the process of evacuating filled thermoplastic bags, pouches,
and the like, the improvement which comprises:
a. providing adjacent first and second vacuum chambers with an
aperture connecting said chambers;
b. placing the filled portion of the bag in the first vacuum
chamber,
c. extending the neck of the bag into the second vacuum chamber,
said bag neck passing through said aperture whereby the mouth of
said bag is unrestrained and open within the second chamber;
d. evacuating the first chamber; and, subsequently,
e. evacuating the second chamber thereby evacuating said bag;
f. stopping the evacuation of the first chamber before the
evacuation of the second is completed; and,
g. closing and sealing said bag.
7. The process of claim 6 including the step of venting said first
chamber to the atmosphere after the evacuation of said chamber has
stopped but before said bag is closed and sealed.
8. An apparatus for evacuating and closing flexible, impervious
receptacles such as pouches, bags and the like which have at least
one opening and contain at least one product comprising:
a. a first vacuum chamber;
b. a second vacuum chamber adjacent to said first chamber;
c. aperture means connecting said chambers for passing the portion
of said package containing an opening therethrough;
d. means to evacuate said first and second chambers independently
of each other; and,
e. means to close said receptacle when its evacuation is
completed.
9. The apparatus of claim 8 wherein said closure means is a metal
clip applying means within said first chamber.
10. The apparatus of claim 9 including control means for said
evacuation means whereby the first chamber will reach maximum
evacuation before the second chamber.
11. The apparatus of claim 10 including wherein said closure means
is a heat seal means.
12. The apparatus of claim 8 including means to vent said chambers
to atmosphere independent of each other.
13. An apparatus for evacuating receptacles into which a product
has been loaded comprising:
a. a first vacuum chamber for receiving the product containing
portion of said receptacle;
b. a second vacuum chamber adjacent to said first chamber;
c. a wall separating said chambers, said wall having an aperture
therein through which a portion of a receptacle containing an
opening may be passed;
d. means for evacuating and venting the first and second chambers
independently of each other; and,
e. closing and sealing means within said first chamber to close
said receptacle after evacuation.
14. The apparatus of claim 13 wherein said closing and sealing
means includes gathering means and clip applying means.
15. The apparatus of claim 13 wherein the means for evacuating and
venting the first and second chambers independently of each other
includes control means whereby said first chamber will reach
maximum evacuation before said second chamber.
16. An apparatus for evacuating filled receptacles such as bags,
pouches, and the like comprising:
a. a base member divided into first and second chamber bases by a
lower wall, said first chamber base being larger than said
second;
b. a cover member hingedly attached to said base member, said cover
member being divided by an upper wall into first and second chamber
heads;
c. a recess in the upper edge of said bottom wall;
d. a recess in the lower edge of said upper wall, said recesses
being complementary whereby when said cover member is rotated to a
closed position first and second vacuum chambers are formed by the
mating of said upper and lower walls and an aperture between said
chambers is formed by said complementary recesses;
e. a vacuum port in said first chamber;
f. a vacuum port in said second chamber;
g. vacuum pump means in communication with each of said ports;
h. control means whereby one chamber may be evacuated and restored
to atmospheric pressure independently of the other; and,
i. receptacle closure means within said first chamber to seal said
receptacle after evacuation has been completed.
17. The apparatus of claim 16 wherein said receptacle is a
thermoplastic bag and said package closure means includes:
1. gathering arms to gather the neck of the bag;
2. clip applying means to apply a clip to said gathered bag neck;
and,
3. severing means to cut off excess material extending beyond the
bag's neck.
18. The apparatus of claim 16 wherein said receptacle is a
thermoplastic bag and the receptacle closure means is heat seal
means.
Description
FIELD OF THE INVENTION
This invention relates to a method and apparatus for evacuating
receptacles, especially impervious, flexible receptacles such as
thermoplastic bags and pouces. The invention has particular
application in the vacuum packaging of fresh and frozen food
products such as beef, poultry, ham, cheese, etc.
BACKGROUND OF THE INVENTION
A number of methods are available in the prior art for packaging
food products such as meat and poultry in flexible containers such
as thermoplastic packages and bags. In some processes the product
is placed in a bag, a vacuumizing nozzle is then inserted into the
bag, the mouth of the bag is gathered around the nozzle while the
vacuum acting through the nozzle withdraws the air from the bag,
and after evacuation is completed the bag is either clamped shut
with a metal clip or heat welded shut. In this method complete
evacuation of the bag is difficult to obtain because the meat
product is usually damp and tends to cling to the bag wall so that
surface crevices in the meat will form a pocket with the bag which
blocks the passage of air out of the bag during the vacuumizing
process. Accordingly, it is one object of the present invention to
provide a method and apparatus for satisfactorily evacuating bags
filled with meat products and the like.
Rather than insert a nozzle into a filled, impervious pouch or bag,
other prior art methods employ a vacuum chamber into which a filled
bag is placed in open condition. Subsequent evacuation of the
chamber also evacuates the bag; and, before the chamber is opened,
the bag is sealed or closed within the chamber. An apparatus for
carrying out such a process is disclosed in U.S. Pat. No. 2,790,284
issued on Apr. 30, 1957 to P. B. Hultkrans. However, the
immediately foregoing method still does not solve the problem of
evacuation of a bag filled with a crevice containing product such
as meat or poultry. Accordingly, it is another object of the
present invention to provide a method and apparatus whereby a
package filled with a product which tends to cling to the package
wall may be evacuated and closed within a vacuum chamber.
Another prior art method and apparatus for evacuating a filled bag
within a vacuum chamber is disclosed in U.S. Pat. No. 3,714,754
issued on Feb. 6, 1973 to Edward L. Holcombe et al. In the Holcombe
et al patent, the bag loaded with a product is placed in a vacuum
chamber and the neck of the bag is clamped over an extractor which
can withdraw vacuum from the bag independently of the vacuum
applied within the chamber. However, this method requires the
manual locating of the bag neck around the extractor tube and the
manual clamping of the bag neck thereto. Accordingly, it is another
object of the present invention to provide an independent means for
evacuating a bag within a vacuum chamber which requires a minimum
of manual handling and locating of the bag within the vacuum
chamber.
The foregoing and other objects are achieved by the process and
apparatus described below.
SUMMARY OF THE INVENTION
In one aspect, the present invention is a process of evacuating
filled receptacles such as thermoplastic bags, pouches, and the
like by placing the filled portion of the bag in a first vacuum
chamber, extending the neck of the bag into a second and adjacent
vacuum chamber, evacuating the first chamber thereby causing the
bag to balloon outwardly away from the product; and, while said
first chamber is being evacuated, evacuating the second chamber
and, consequently, evacuating the interior of the ballooned bag;
thereafter when evacuation of the bag is complete, elevating the
pressure in the first chamber to collapse the bag firmly around the
product and immediately closing the bag thereby making an evacuated
package.
In another aspect, the present invention is a process of evacuating
and closing flexible, impervious receptacles such as pouches, bags,
and the like which have at least one opening and certain at least
one product, the process comprising the steps of confining the
product containing a portion of the receptacle within a first
region, confining a portion of the receptacle which contains the
opening in a second region so that the interior of said receptacle
is in communication with the second region through said opening of
the receptacle, reducing the pressure within said first region and,
subsequently, reducing the pressure within said second region so
that the interior of the receptacle is evacuated, elevating the
pressure in the first region, and, thereafter, closing the opening
to make an evacuated package.
In still another aspect, the present invention is an apparatus for
evacuating and closing flexible, impervious receptacles such as
pouches, bags, and the like which have at least one opening and
contain at least one product and the apparatus comprises a first
vacuum chamber with a second vacuum chamber adjacent to it and an
aperture connecting the two chambers for passing the portion of the
receptacle containing an opening therethrough. Means to evacuate
the first and second chambers and means to close the package when
its evacuation is completed are included in the apparatus. Also,
the closing means for the apparatus may be either a clip applying
device or a heat seal apparatus located within one of the vacuum
chambers.
The invention may be better understood by reference to the drawings
described below and the following Description of the Preferred
Embodiment.
DESCRIPTION OF THE DRAWINGS
In the drawings which are appended hereto and made a part of this
disclosure;
FIG. 1 is a side elevational representation of a preferred
apparatus according to the present invention in which the vacuum
chambers of the apparatus are closed and a chamber wall is removed
to show the interior arrangement;
FIG. 2 is a top plan view of the apparatus shown in FIG. 1 with
both of said vacuum chambers open;
FIG. 3 is an isometric representation of a section of the lower
portion of both of said vacuum chambers showing a filled package
ready to be evacuated;
FIG. 4 is a representation in partial section showing the gathering
arms of the preferred closing means of the preferred apparatus;
FIG. 5 shows in partial section a clip being applied to a bag neck
which has been gathered by the gathering arms shown in FIG. 4;
FIG. 6 shows the clip of FIG. 5 being closed around the gathered
bag neck as the clip is forced into the clip anvil;
FIG. 7 is a sectional schematic side representation of the base of
the vacuum chambers of the preferred embodiment showing the clip
magazine and the clip punch and driving wheel; and,
FIG. 8 is a front elevational representation of the drive and
timing wheel shown in FIG. 7.
DEFINITIONS
As used herein, the terms listed below will be understood to have
the meaning set forth beside each term:
"Receptacle" means any container for receiving an article or
product to be packaged in the receptacle and includes bags and
pouches.
"Bag" means a receptacle or container constructed from tubular
stock by sealing one end of the tube. A bag may be pleated or
gusseted.
"Pouch" means a receptacle or container constructed from sheet
stock. A single or multiple sheets may be used; and, commonly a
pouch may be made by folding a single sheet and sealing the free
edges of the sheet together.
"Aperture" means a hole in a wall that may be of any shape and
includes slot, oval, circular, rectangular, and irregular shaped
holes. An aperture may be formed by joining two wall sections that
have indentations in one or both of the surfaces so joined.
"Vacuum" means a pressure level lower than atmospheric pressure and
may be expressed in lbs./sq.in. or in inches of Hg. A "high" vacuum
means a very low pressure level.
"Heat shrinkable" means that the particular material referred to
will shrink upon the application of heat.
"Heat sealable" means that the particular material referred to can
be welded to itself under the influence of temperature and
pressure.
"Opening" in a receptacle means a passageway from the exterior of
the receptacle to the interior; and, in the case of a bag, the
"opening" can be the bag's mouth and the part of the bag containing
the "opening" would be the bag's neck.
PREFERRED EMBODIMENT
In FIG. 1, a double chamber vacuumizing apparatus 1 is shown in a
side elevational representation with the side wall of the apparatus
cut away so that the interior arrangement may be clearly seen.
Also, reference will be made to FIG. 2 which is a top plan view of
the apparatus of FIG. 1 with the hinged cover or head 3 being open.
The cover 3 is hinged to base member 2 which is divided by lower
chamber divider wall 12 which cooperates with the upper divider
wall 11 to separate apparatus 1 into the two chambers or regions 4
and 5. The first and larger region or chamber 4 is the product
chamber in which the portion of a bag or receptacle 9 containing a
product 8 is placed on product conveyor 14. The receptacle opening
or bag neck is extended into the second and smaller region 5 which
serves as the receptacle or bag evacuation chamber. The second
chamber 5 is evacuated through vacuum port 7 and the first chamber
4 is evacuated through vacuum port 6.
Looking now at FIG. 3, the extension of the neck of bag 9 from the
first chamber 4 into the second chamber 5 can be more clearly seen.
The operator of the apparatus 1 receives the bag 9 filled with a
product 8 and places the bag on the conveyor 14 and brings the neck
of the bag down through the bag neck guide 13 and extends the neck
of the bag across walls 18a and 18b of the gathering arm track 18,
across plunger housing 21, cutter housing 22, and the recess 12a in
wall 12 so that the opening 9b of the package is located in the
second region or chamber 5 just above the evacuation port 7. The
recess 12a in the wall 12 forms the lower half of the aperture in
the wall which divides chambers 4 and 5 and this aperture and wall
is completed when the cover 3 is rotated into the position shown in
FIG. 1 so that a corresponding recess in wall 11 forms the upper
half of the divider wall aperture.
Once the chamber is closed evacuation of chamber 4 begins through
vacuum port 6. Any conventional vacuum pump which is well known in
the art may be used and be connected to vacuum port 6 to evacuate
chamber 4. As vacuum is applied the chamber will be evacuated very
rapidly, in the order of 2 to 3 seconds to a low level of pressure
or around 27 inches of Hg. and further reduction in pressure takes
a significantly longer period of time. The bag neck sufficiently
fills the aperture between chambers 4 and 5 so that very little air
is leaked from the second region 5 into the first region 4 during
this phase of evacuation. In this initial phase, the bag 9 will
balloon outwardly as shown by dotted lines 10 because of the
difference in pressure between the interior of the bag 9 and the
chamber 4. This outward expansion of ballooning of the bag also
occurs in the bag's neck region and the expanded neck further seals
the aperture between chambers 4 and 5. While the bag is ballooned
into shape 10, evacuation of the second region or chamber 5 is
begun. This will usually be of the order of one-half sec. after the
beginning of the evacuation of chamber 4. Chiefly because of its
smaller size, the evacuation of the second chamber 5 proceeds at a
more rapid rate than that of first chamber 4 and overtakes the
vacuum level in first chamber 4 thus causing the ballooned bag 10
to begin to collapse back onto product 8. The second chamber 5 will
reach a vacuum level of 28 inches of Hg. or lower depending on the
period of time vacuum is supplied through port 7. As the vacuum
level in the second chamber 5 is reduced below that in chamber 4
and the bag 9 begins to collapse back upon the product 8,
atmospheric pressure is restored in chamber 4 by stopping the
vacuum pumping action through port 6 and venting the chamber to the
atmosphere by valve means which are not shown. This sudden increase
in the pressure differential between the inside and outside of the
bag will cause the bag to collapse rather rapidly and suddenly
driving out any remaining air. Immediately as this takes place, the
bag is clipped and closed as will be described more fully
hereinafter.
Once the bag is clipped and closed, the excess bag neck material is
trimmed off and the head or cover 3 is opened and conveyor 14 will
start up and deliver the sealed bag to conveyor 16 while the
operator is preparing to place another filled bag within apparatus
1 to begin the process again.
When , as described above, the bag balloons outwardly to the shape
10 the bag wall is separated from the product 8 and any crevices or
cavities in the product are exposed to the space which now exists
between product 8 and the expanded bag wall 10. Thus, when
evacuation of the second chamber 5 begins, a continuous passageway
exists whereby a substantial portion of the surface of the product
8 is brought directly under the influence of the vacuum being drawn
through second chamber 5.
A preferred package or bag closing and sealing means is illustrated
in FIGS. 3-7. FIG. 4 is a view in partial section looking along the
direction of lines 4--4 of FIG. 3. This view is from between walls
18a and 18b of the lower gathering arm guide track 18 and between
walls 17a and 17b of the upper gathering arm track 17. In FIG. 4
bag neck 9a is shown partially compressed between the bag neck
guide 13 and walls 17a and 18a. Gathering arms 25 move inwardly
towards each other to further compress the bag neck 8 into the
shape shown in FIG. 5. As the gathering arms 25 have moved more
closely together to wedge the bag neck 9a into a smaller space,
plunger 24 drives clip 37 up around the gathered bag neck 9a and
forces the clip towards anvil 19. Further motion of the plunger
forces the clip into the anvil 19 and bends it into the shape shown
in FIG. 6 securely around the bag neck 19 thereby closing and
sealing same. As this is completed cutter arm 26 with serrated
cutter blade 27 is driven upwardly to cut off the excess bag
material which extends beyond clip 37. The clip 37 is taken from
the group of clips 33 contained in clip magazine 32 shown in FIG.
7. The clips 33 are urged forward in the magazine 32 under the
influence of clip spring 34 and are delivered to plunger 24
immediately below plunger housing 21. Plunger 24 is connected to
plunger crank arm 29 at pivot 30, and crank arm 29 is driven by
timing wheel 28 to which it is connected by crank pin 35.
Cutter arm 26 is driven upwardly through cutter housing 22 to sever
the excess bag neck material and the drive means for cutter arm 26
is not shown but may be a pneumatically operated cylinder or an
electrically driven solenoid, both of which drive means are well
known in the art.
An alternate method and means for closing a package or bag after
evacuation is to remove the bag neck guide 13 shown in FIG. 3 and
widen the aperture opening 12a to correspond to the width of the
flattened bag neck. The clip applying means may be eliminated in
this alternate closure means and a sealing bar may be substituted
for the blade 27 with the sealing bar being the same width as the
aperture 12a. Bar 27 may be electrically resistance heated and a
pressure backing member may be substituted for the cutter track 38
as shown in FIG. 6 so that when the arm 26 is driven upwardly after
the evacuation of the bag the heated bar 27 will contact the
flattened bag neck 9a and press same against the pressure backing
member 38. The bar would dwell sufficiently long in its position of
pressing the bag neck against the backing member 38 until the bag
is sealed to itself. Of course, for this alternate method and means
to be employed the bag material must be of a type that will weld to
itself under the influence of heat and the thermoplastic material
such as polyethylene, ethylene vinyl acetate copolymers, saran, and
the like with the appropriate coatings and surface treatments are
suitable for this purpose.
FIG. 8 is a frontal view of the plunger drive wheel 28 which is
driven by pinion 36 which, in turn, is driven by a conventional
electrical motor which is not shown. Crank pin 35 is connected to
plunger crank 29 and at the beginning of each cycle crank pin 35 is
at bottom dead center of the wheel. The time represented by t.sub.1
is the time from the beginning of the clip's engagement with the
anvil to the end of the engagement as the plunger withdraws.
Referring also to FIG. 7, timing cams may be placed on shaft 31 on
which wheel 28 is mounted and these cams can be used to control
such functions as the venting of the chambers to atmosphere as the
clipping and cutting cycle is completed.
Referring now to FIGS. 1-8, a semi-automatic operation of the
foregoing described apparatus according to the process of the
present invention will be described. In the following description
valves, cams, a timer, vacuum pump, pressure sensor, etc. are
mentioned. None of these are shown in the drawings and each is a
conventional item whose use and application is familiar to those
skilled in the packaging machinery arts. The packaging cycle begins
when the operator manually places a filled bag into first chamber 4
and extends the neck into second chamber 5. The operator then
closes the chambers with cover 3 and the closing actuates a
microswitch which starts a timer and opens the valve to port 6 so
that a vacuum pump can evacuate chamber 4. At a predetermined time,
preferably of the order of one-half or five-eighths of a second
after the evacuation of the first chamber has begun depending on
the size of the chamber and power of the vacuum pump, the
evacuation of the second chamber is started by the timer opening
the valve connecting port 7 with the vacuum pump. During this time
ballooning of the bag 9 to shape 10 will have occurred. When the
pressure in the first chamber reaches a preset level, preferably
about 26 or 27 in. Hg., a pressure sensor in the first chamber
shuts off the vacuum in the first chamber and simultaneously sends
a signal through a delay timer to the electric drive motor for
pinion 36. At this point, the timing and drive wheel 28 is at the
position shown in FIG. 8 with the crank pin at bottom dead center.
The timed signal can be preset for any given duration and is
preferably about 11/2 seconds which means that wheel 28 will start
to make one complete revolution at the end of that preset period of
time. Timing cams are located on the supporting shaft or axle 31 of
wheel 28 and as wheel 28 rotates in a counterclockwise manner (FIG.
8) one of the cams will actuate a valve causing the first chamber
to vent to atmosphere prior to reaching time span t.sub.1. Venting
the first chamber to atmosphere causes the bag 9 to collapse or,
rather, be violently pushed against the product since the bag
interior is at the pressure level of the second chamber which now
will have reached lower than 28 in. Hg. This violent collapsing of
the bag drives out any residual air in the bag immediately before
the gathering and clipping cycle begins with time span t.sub.1.
During t.sub.1, the bag neck is gathered and the clipper plunger 24
drives clip 37 into position around the gathered bag to seal and
close same. Following withdrawal of the plunger and trimming of the
bag neck at the end of t.sub.1, a second cam shuts off the vacuum
to the second chamber and vents that chamber to the atmosphere. The
cover 3 may now be raised and while the operator is getting another
filled bag ready, conveyor 14 moves the completed package to exit
conveyor 16.
It is to be understood that the present invention is not limited to
bags and pouches but can be applied generally to any receptacle
whose walls will flex outwardly under the influence of a pressure
differential and will conform to a wall aperture. Furthermore, as
set forth above, the shape of the wall aperture may be made to
conform to the shape of the receptacle opening and to the closing
and sealing method desired.
One particularly desirable package results from the process and
apparatus of this invention when a meat or poultry product is
enclosed in a heat shrinkable, essentially gas impervious,
thermoplastic bag. After the meat product has been sealed in the
bag and the resulting package conveyed out of the apparatus, the
package is passed through either a hot water bath or through a hot
air tunnel to shrink and further tighten the bag material around
the product. Te tight grip of the shrunken material protects the
product from pinhole leakage because the material is so firmly
pressed against the product that even when a hole or cut occurs the
hole is essentially sealed by the adjacent or exposed portion of
the product so that no air can enter the package.
* * * * *