U.S. patent number 3,851,437 [Application Number 05/423,345] was granted by the patent office on 1974-12-03 for receptacle evacuation apparatus and method.
This patent grant is currently assigned to W. R. Grace & Co.. Invention is credited to Stanley D. Hall, Thomas E. Waldrop.
United States Patent |
3,851,437 |
Waldrop , et al. |
December 3, 1974 |
RECEPTACLE EVACUATION APPARATUS AND METHOD
Abstract
A receptacle whose interior is in communication with a portable
vacuum reservoir can have its interior evacuated within a vacuum
chamber and then be removed from the chamber so that final closing
of the receptacle takes place outside the chamber thus freeing the
chamber for a subsequent receptacle.
Inventors: |
Waldrop; Thomas E. (Greer,
SC), Hall; Stanley D. (Greer, SC) |
Assignee: |
W. R. Grace & Co. (Duncan,
SC)
|
Family
ID: |
23678551 |
Appl.
No.: |
05/423,345 |
Filed: |
December 10, 1973 |
Current U.S.
Class: |
53/434; 53/86;
53/512 |
Current CPC
Class: |
B65B
31/024 (20130101) |
Current International
Class: |
B65B
31/02 (20060101); B65b 031/02 (); B65b
031/04 () |
Field of
Search: |
;53/22B,86,112B |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McGehee; Travis S.
Attorney, Agent or Firm: Toney; John J. Lee, Jr.; William
D.
Claims
Having thus described our invention, we claim:
1. In the method of evacuating receptacles within a vacuum chamber,
the improvement which comprises:
a. providing a portable vacuum reservoir;
b. placing said receptacle and said reservoir within a vacuum
chamber, said reservoir being in communication with the interior of
said receptacle;
c. evacuating said reservoir and said receptacle;
d. sealing the evacuated reservoir while leaving it in
communication with the receptacle; and,
e. removing the receptacle and reservoir from said chamber and
thereafter closing said receptacle.
2. The method of claim 1 wherein said receptacle is a flexible,
thermoplastic bag.
3. The method of claim 2 including the step of evacuating the
vacuum chamber while said reservoir and receptacle are being
evacuated.
4. The method of claim 4 including the steps of providing a nozzle
in communication with said reservoir and clamping the neck of the
bag thereto.
5. A method of evacuating receptacles containing a product
comprising the steps of:
a. providing a vacuum reservoir in communication with the interior
of said receptacle;
b. placing said reservoir and receptacle in a vacuum chamber;
c. evacuating the chamber, reservoir, and receptacle;
d. sealing the reservoir but leaving it in communication with the
interior of the receptacle;
e. removing said receptacle and reservoir from said chamber; and,
thereafter,
f. sealing said receptacle and severing its communication with said
reservoir.
6. Apparatus for evacuating receptacles comprising:
a. a vacuum reservoir;
b. means for communicating said reservoir with the interior of a
receptacle;
c. vacuum chamber means for receiving said reservoir and
receptacle;
d. means for evacuating said chamber, reservoir, and
receptacle;
e. means for sealing said reservoir after it has been evacuated;
and,
f. means for closing said receptacle and severing its communication
with said reservoir.
7. The apparatus of claim 6 wherein the means for communicating
said reservoir with the interior of a receptacle is a clamping
nozzle with an evacuation port and passageway therein.
8. The apparatus of claim 7 including a conveyor belt to transport
said receptacles to and away from said vacuum chamber.
9. The apparatus of claim 8 wherein said clamping nozzle and said
reservoir are mounted on a support plate, said plate being mounted
on said conveyor belt.
10. The apparatus of claim 9 including a port and check valve in a
wall of said reservoir whereby said reservoir will be evacuated as
said chamber is evacuated.
11. The apparatus of claim 9 wherein said reservoir has a bottom
port and a valve to control the opening and closing thereof, said
support plate and conveyor belt having orifices aligned with said
port whereby said reservoir may be evacuated through said port and
orifices.
12. Apparatus for evacuating filled, flexible receptacles
comprising:
a. a conveyor belt mounted for intermittent motion, said belt
having an evacuation orifice therein;
b. a support plate mounted on said conveyor, said plate having an
orifice aligned with the orifice in said belt;
c. a clamping nozzle mounted on said plate, said nozzle being
adapted to clamp the necks of flexible receptacles thereto;
d. a vacuum reservoir mounted on said plate, said reservoir having
a port in its bottom wall aligned with said orifices;
e. a valve for controlling the opening and closing of said port,
said valve opening when the air pressure in said port and orifices
is lower than the pressure in the reservoir and closing when the
air pressure in said port and orifices is equal to or greater than
the pressure in said reservoir;
f. a vacuum line connecting said clamping nozzle and said reservoir
whereby the interior of a clamped receptacle is in communication
with said reservoir;
g. a vacuum chamber into which said reservoir and nozzle may be
conveyed by said belt;
h. a vacuum port beneath said belt whereby said orifices and
reservoir port may be aligned when said reservoir and nozzle are
within said chamber;
i. means for evacuating said chamber;
j. means for evacuating said reservoir through said ports and said
orifices;
k. means outside said chamber for closing and severing the
receptacle while it is in communication with said reservoir.
13. The apparatus of claim 12 wherein said clamping nozzle
comprises a slidable barrel; a clamping plunger mounted coaxially
within said barrel, said plunger having an evacuation passageway
therethrough; and, a locking handle to hold said plunger and barrel
in a fixed position with a portion of the neck of a receptacle
clamped therebetween.
14. Apparatus for evacuating filled, flexible receptacles
comprising:
a. a conveyor belt mounted for intermittent motion;
b. a support plate mounted on said conveyor;
c. a clamping nozzle mounted on said plate, said nozzle being
adapted to clamp the necks of flexible receptacles thereto;
d. a vacuum reservoir mounted on said plate, said reservoir having
a port in one of its walls;
e. a valve for controlling the opening and closing of said port,
said valve opening when the air pressure exterior of said reservoir
is lower than the pressure inside the reservoir and closing when
the air pressure exterior of said reservoir is equal to or greater
than the pressure inside said reservoir;
f. a vacuum line connecting said clamping nozzle and said reservoir
whereby the interior of a clamped receptacle is in communication
with said reservoir;
g. a vacuum chamber into which said reservoir and nozzle may be
conveyed by said belt;
h. means for evacuating said chamber whereby said reservoir and bag
interior are consequently evacuated; and,
i. means outside said chamber for closing and severing the
receptacle while it is in communication with said reservoir.
Description
FIELD OF THE INVENTION
This invention relates to the evacuation of receptacles to
pressures lower than that of the atmosphere. Particularly, this
invention relates to the evacuation and sealing of filled, flexible
receptacles such as thermoplastic bags to very low pressure levels
in order to preserve the contents of the receptacle. A useful
application of the invention is in the packaging of food products
such as meat and poultry, cheese, and other foods whose storage
lifetime is increased by the absence of atmospheric air.
BACKGROUND OF THE INVENTION
It is well known to package and store articles, particularly food
products, in receptacles in which substantially all of the
atmospheric air has been removed. One apparatus and method for
evacuating flexible receptacles such as thermoplastic bags filled
with a food product is disclosed in U.S. Pat. No. 3,714,754 issued
to E. L. Holcombe et al. on Feb. 6, 1973. In that patent, a
thermoplastic bag filled with a food product is conveyed into a
vacuum chamber where the pressure is lowered to remove the air from
the bag; and, after a sufficiently low pressure has been reached
the bag neck is clipped shut by the application of a metal clip
which effects a hermetic or air tight closure of the bag. However,
the process is somewhat slowed down by the fact that there is a
delay of the product in the vacuum chamber while it is being
closed. Accordingly, it is one object of the present invention to
provide a method and apparatus whereby a receptacle may be
evacuated within a vacuum chamber and then finally sealed and
closed outside of the vacuum chamber.
Another object of the present invention is to provide a method of
evacuating and sealing filled receptacles at speeds greater than
prior art methods.
These and other objects accomplished by the present invention will
be apparent to those skilled in the art from the following
description of the invention.
SUMMARY OF THE INVENTION
The present invention is a method and apparatus whereby a
receptacle whose interior is in communication with a vacuum
reservoir can have its interior evacuated within a vacuum chamber
and then be removed from the chamber so that final closing of the
receptacle takes place outside of the chamber thereby freeing the
chamber for a subsequent receptacle.
Specifically, the method of the present invention comprises the
steps of providing a vacuum reservoir in communication with the
interior of a receptacle; placing the reservoir and receptacle
within a vacuum chamber; evacuating a chamber, reservoir, and
receptacle; sealing the reservoir but leaving it in communication
with the interior of the receptacle; removing said receptacle and
reservoir from said chamber; and, thereafter, sealing said
receptacle and severing its communication with the reservoir.
The apparatus of the present invention comprises a vacuum
reservoir; means for communicating said reservoir with the interior
of a receptacle; vacuum chamber for receiving said reservoir and
receptacle; means for evacuating said chamber, reservoir and
receptacle; means for sealing said reservoir after it has been
evacuated; and, means for closing said receptacle and severing its
communication with said reservoir.
In one embodiment of the present invention, the reservoir and the
receptacle may be evacuated independently of the evacuation of the
vacuum chamber; and, in a second embodiment, the reservoir and
receptacle are evacuated as the vacuum chamber is evacuated. A
chief advantage in evacuating a receptacle within a vacuum chamber
according to the present invention is that as the chamber pressure
is lowered more rapidly than the pressure inside of the receptacle,
the receptacle will expand outwardly if it is flexible thus
exposing all of its interior to the evacuation means with which it
is in communication. This is especially important for meat and
poultry products which have crevices and cavities and are damp when
packaged so that the receptacle wall would tend to stick to the
damp product thus trapping air in the crevices and cavities. Once
the outward expansion or "ballooning" had taken place and the
receptacle thereafter evacuated, in prior art devices it was
necessary to retain the product in the vacuum chamber until it was
finally clipped in order to insure that air did not leak back into
the bag. In the present invention, when the receptacle is flexible
and has been collapsed tightly around the product after evacuation
of the receptacle, there is little, if any, space or volume within
the receptacle that is not occupied by the product whereas the
reservoir which is in communication with the interior of the
receptacle is a relatively large volume or space which has been
essentially completely evacuated of any air or gas and serves as a
vacuum reservoir. The difference in volume between the vacuum
reservoir and the unoccupied space within the receptacle being
quite great, the reservoir can absorb any leakage of air into the
receptacle when the receptacle is removed from the vacuum chamber
before it is clipped, sealed, or closed.
The present invention may be even better understood by referring to
the following detailed description and to the attached drawings
which are described below.
DESCRIPTION OF THE DRAWINGS
In the drawings which are attached hereto and made a part
hereof:
FIG. 1 is a top plan view of the vacuumizing machine employing a
vacuum reservoir according to the present invention;
FIG. 2 is a side elevation view of the machine shown in FIG. 1;
FIG. 3 is a schematic representation of the operation of the vacuum
reservoir within a vacuum chamber;
FIG. 4 is a perspective view of a bagged product and the reservoir
assembly showing the bag's neck over the clamping nozzle;
FIG. 5 is a sectional view of a clamping nozzle; and,
FIG. 6 is a top plan view of one embodiment of a reservoir assembly
according to the present invention.
PREFERRED EMBODIMENT
In FIGS. 1 and 2 a flexible receptacle or bag evacuation apparatus
or machine 5 is illustrated. The major components of the machine 5
include a conveyor belt 3, a reservoir assembly 1, a vacuum chamber
4, and a bag closing means 10.
In operation these components relate to one another and function in
the following manner;
Still referring to FIGS. 1 and 2, receptacles or bagged products 2
are delivered to the machine by any convenient means; e.g., infeed
conveyor 6, whereupon the bagged products are deposited on the
conveyor belt 3 and placed on the clamping nozzles 33 by operators
8. The bagged products are transported to vacuum chamber 4, which
is raised to an open position by cam-driven pushrods (not shown),
the cams rotating as the belt moves to cycle the chamber cover up
and down once for each reservoir assembly 1. Sensor 32 acts to
introduce vacuum to line 23 so that suction will be present at port
22 when the reservoir arrives there. After the vacuumizing
operation within the chamber 4, which will be discussed
hereinafter, the bagged products are conveyed to a bag sealing
means located outside of the chamber; e.g., a clipping-severing
device 10 supported by frame 9. The sealed bags may be transported
from the machine by any effective means; e.g., discharge conveyor
7.
Referring now to FIGS. 3 and 4 wherein there is shown a schematic
and a perspective view, respectively, of the reservoir assembly 1,
a bagged product 2 is shown resting on conveyor belt 3 with the
neck of the bag on neck or throat gathering support 24 with the
open end of the bag clamped on nozzle 33. As illustrated, the
nozzle is mounted on support 13 which is attached to a reservoir
support plate 12 which is fixedly attached to conveyor belt 3.
Turning now to FIG. 3, which schematically represents the operation
of the reservoir 11 within the vacuum chamber, there is shown an
inverted U-shaped housing valve 19 wherein the top most side,
having an opening therein, also serves as a valve seat for check
valve 20 having closure spring 21. The housing 19 is located over
an opening in plate 12 and port 22 beneath the conveyor belt. As
shown in FIG. 3, when the reservoir is in operation, the port 22
lies coincidentally with vacuum line 23.
Certain variations may be made in the components of the receptacle
evacuation apparatus as described and shown and still fall within
the generally preferred embodiment of the present invention. For
instance, it is not necessary that two bagged products be evacuated
and sealed simultaneously. One or any additional number of bagged
products within practical limits may be evacuated and sealed.
Furthermore, although preferred, it is not necessary in some
instances to employ mechanical bag closing devices of the type
shown which is Tipper Clipper Model AZ4100 manufactured by the
Tipper Tie Division of Rheem Manufacturing Company of New York,
N.Y. and which closes the bags with metal clips. For instance, the
bag's open end may be closed by heat sealing means. Any well-known
sensing device 32 for actuating vacuum line 23 may be used
including both electrical and pneumatic switches. The vacuum
chamber cover 4, as stated before, is raised by cam-driven pushrods
but may be raised by actuating means such as pneumatically driven
pistons or by electrically driven motors or solenoids.
The sequence of events during the operation of the apparatus are as
follows:
The major events to be sequenced are: (1) clamping the bagged
products on the vacuum nozzles; (2) conveying the clamped bagged
product to the vacuum chamber; (3) opening the vacuum chamber; (4)
stopping the conveyor belt; (5) closing the vacuum chamber; (6)
evacuating the chamber; (7) evacuating the reservoir assembly; (8)
discontinuing evacuating chamber, (9) venting chamber to
atmosphere; (10) conveying bagged product which is under vacuum
because of the reservoir to a bag sealing device; (11) sealing the
bag and severing it from the nozzle which automatically vents the
reservoir assembly to atmosphere; and (12) conveying the sealed
bagged product to the discharge end of conveyor.
Most of the components required for the sequencing events, as
outlined heretofore, are well known in the art; e.g., as shown in
U.S. Pat. No. 3,714,754, which was mentioned hereinabove.
Turning now to the clamping nozzle, its operation will be described
below:
Many different evacuation nozzle designs are available and
applicable to the operation of this receptacle evacuation
apparatus, particularly when the receptacle is flexible. One
particularly pertinent nozzle is disclosed in U.S. Pat. No.
3,094,825. The nozzle disclosed in this patent has a coaxially
disposed flared nozzle extension in the center of the nozzle barrel
which serves to clamp the neck of a bag between the flared
extension or plunger and the barrel of the nozzle.
Another pertinent nozzle is disclosed in U.S. Ser. No. 258,665, now
U.S. Pat. No. 3,780,489, which is assigned to this assignee of the
present application. The nozzle disclosed in this patent has a
barrel slidably mounted in a cover and has upper and lower nozzle
portions coaxially positioned in the barrel. The upper and lower
portions have mating flanges and are resiliently held together.
Attached to the lower end of the lower nozzle portion is a flared
resilient plunger which is positioned outside of the barrel so that
a bag neck can be clamped therebetween. The lower nozzle portion
can be swung a limited distance like a pendulum and such motion
will separate the mating flanges on the nozzle portions. The upper
portion is provided with a central vacuum duct or passageway and
the separation of the flanges will introduce vacuum into the
barrel, and the barrel, being slidably mounted, will move down upon
the plunger under the force created by the air pressure
differential, thus clamping the bag between the plunger and the
barrel and at the same time introducing vacuum into the interior of
the bag. This clamping action will hold a filled bag. The vacuum
valve and clamping action are released by the introduction of
compressed air into the barrel.
In addition to the two above described nozzles, the preferred
clamping nozzle 33, as shown in FIG. 5 has a barrel 14 moveably
mounted on plunger 16 which is fixedly connected to clamping nozzle
support 13. As shown in FIGS. 3 and 4 said nozzle support is
mounted on reservoir support plate 12 which in turn is mounted to
conveyor belt 3. Flared plunger head 25 is located on the external
forward end of the plunger and annularly located in the internal
forward portion of the barrel is chamber or cavity 30 having a
vacuum supply line 15 (vacuum source not shown) connected thereto.
A second vacuum line 23A runs through the plunger and plunger head
of the nozzle and is connected to product evacuation line 18 from
the reservoir (FIGS. 3 and 4) to communicate the interior of the
bag or receptacle with the interior of the reservoir.
A locking handle 17 is moveably mounted to the barrel by means of
handle pivot plate 27. Said pivot plate is pivotally attached to
the barrel and is further attached to arm 26 at second pivot point
29'. Said arm is pivotally attached at third pivot point 29" to a
fixed pivot plate 28 which in turn is attached to support 13.
The advantage of the design of nozzle 33 over prior art is better
illustrated by an understanding of the operation of this unique
clamping nozzle. The neck of a bag 2 is placed around barrel 14 of
nozzle 33 (not shown) by an operator 8 (FIG. 1) and a vacuum is
applied to barrel chamber 30 through passageway 15. Because of the
force created by the air pressure differential, the moveable barrel
will slide toward plunger head 25 thereby clamping the neck of the
bag between the barrel and the plunger head. To further clamp the
neck of the bag between the barrel and plunger head the operator
pushes handle 17 toward support 33 to a closed position thereby
forcing the barrel against the plunger head forming a leak proof
clamp around the neck of the bag.
Next, the operation of the reservoir assembly will be described
with reference to FIGS. 3, 4, and 6 in the following
paragraphs:
In FIG. 4 the components of the reservoir assembly are shown in
perspective. Support plate 12, nozzle support 13, clamping nozzle
33, receptacle evacuation line 18, and reservoir 11 comprise the
reservoir assembly. Also included for bag-like flexible receptacles
is bag neck gathering support 24. The support plate 12 which
supports the other components is carried by conveyor belt 3. These
same components of reservoir assembly 1 may be seen in FIG. 6 where
a top plan view of the assembly is shown. The top wall of reservoir
11 is broken away to show the location of check valve 20 in the
bottom wall of the reservoir. Reservoir latches 31 allow the
reservoir to be opened and cleaned should any moisture or debris
collect in the reservoir. In FIG. 6, clamping nozzle 33 is shown
with the clamping plunger 25 (see FIG. 5) closed against barrel 14
so that the locking handle 17 is in the "down" or locked position
whereas in FIG. 5, handle 17 is in the "up" or unlocked
position.
In operation, the neck or throat of a bag or receptacle 2 will be
placed around nozzle 33 as shown in FIG. 4. The nozzle is then
actuated and the bag clamped securely as described above. Then, the
bag 2 and reservoir assembly are placed in a vacuum chamber 4 as
shown in FIG. 3. In the preferred embodiment, as shown, the check
valve 20 is aligned with flanged vacuum port 22 so that air can be
withdrawn through the aligned orifice which is defined by the lower
opening of valve housing 19 as the housing extends through support
plate 12 and through a matching orifice in belt 3. When the air
pressure in vacuum line 23 is lowered below the pressure in the
reservoir 11, valve 20, which is hingedly attached to housing 19 to
cover the upper opening or orifice of housing 19, will be forced
open against valve spring 21 by the difference in pressure. When
the pressure in the line 23 or, after movement from alignment with
line 23, when the pressure exterior of the reservoir 11 is greater
than that in the reservoir, valve 20 will close. It is to be
understood that other valves could be used and be within the scope
of the present invention. For example, a poppet valve, a ball
valve, or a butterfly valve could be used. The valve spring in each
instance would, of course, have to be selected so that the valve
opens at the desired pressure differential. One preferred valve is
a swing check valve Model Number 583-1D2 made by Teledyne Rupublic
Manufacturing Co.
Still referring to FIG. 3, once evacuation has begun in the vacuum
chamber 4 through line 34 which is connected to a vacuum pump (not
shown) which is preferably a conventional pump such as a 300 CFM
Nash pump, the bag or flexible receptacle 2 will balloon outwardly
as indicated by dotted line 2' due to the pressure difference
between the inside and outside of the bag. If the bag or receptacle
has been filled with a meat or poultry product containing crevices
or cavities, these crevices will now be subjected to evacuation
when air is withdrawn through vacuum line 23, valve 20, reservoir
11, line 18, and nozzle vacuum line 23A. (see FIG. 5) The vacuum
applied through line 23 may come from the same pump as used to
evacuate the chamber 4 or it may be from an independent pump. Once
the evacuation of the receptacle 2 and reservoir 11 is complete
atmospheric air will be introduced into the chamber causing the
receptacle 2 to collapse upon the product inside. When the vacuum
to line 23 is stopped, the valve 20 will close and the reservoir
assembly 1 and receptacle 2 are moved to clipper 10 (see FIG. 1)
outside the chamber 4 for final closure of the receptacle. Since
virtually all air has been removed from the receptacle any leakage
of air into the receptacle will be evacuated to reservoir 11 as the
difference in volume is so great that the lower pressure will be
effectively maintained. For example, in one embodiment the
reservoir has a volume of about 350 cubic inches while there is
virtually no measureable cavity volume in the flexible receptacle
because its walls are collapsed and held against the product by the
pressure differential of about 29 inches of Hg. Thus, clipping the
receptacle outside the vacuum chamber while a subsequent package is
being evacuated within the chamber saves the time of the entire
clipping procedure each cycle of the apparatus.
Referring again to FIG. 3, in another embodiment, valve 20 with its
housing 19 may be placed in a side or top wall of reservoir 11 and
the bottom wall will not be provided with an opening. This
configuration is not shown in FIG. 3; but, when used, the bag 2
will balloon outwardly as before because the pressure in chamber 4
will decrease more rapidly then the pressure inside the reservoir
and bag because the air leaving bag 2 has a more restricted path to
travel by going through line 18, reservoir 11, and valve 20. This
embodiment makes use of one vacuum line 34 and eliminates the need
for vacuum line 23 as the check valve 20 will open to evacuate the
reservoir 11 and bag 2 as soon as the chamber 4 pressure is
lowered.
* * * * *