Apparatus for providing containers with a controlled environment

An apparatus for providing a container with a controlled environment utilizing a plunger having openings with a contour complementary to an opening in the container. The apparatus is useful, for example, in food packaging applications whereby oxygen is removed from the food containers and replaced with a substantially inert environment prior to sealing the containers.

TECHNICAL FIELD 
This invention relates to an apparatus for exposing a container to a 
controlled environment, such as to accomplish removal of one environment 
from a container or sequence of containers and replacement with a new 
environment. More particularly, the invention is directed toward nearly 
complete removal of atmospheric oxygen from containers for storing oxygen 
sensitive food products using an inert environment. 
BACKGROUND OF THE INVENTION 
In certain industries it is necessary to remove as much of an original 
environment from contact with a product as possible and to replace it with 
a new environment. Fat and oil containing foods, for example are very 
susceptible to attack from oxygen and can be preserved much longer in its 
absence. A near complete removal of oxygen from containers for storing 
oxygen-sensitive products has, until now required complex and/or expensive 
equipment and often has required specialized and/or expensive containers. 
Oxygen removal has traditionally been accomplished by packaging under 
vacuum or with a combination of inert gas and vacuum, see U.S. Pat. No. 
2,718,345 issued to Howard. Plungers have been disclosed in the prior art 
for use under these traditional removal processes, see U.S. Pat. No. 
3,508,373 issued to Robinson; U.S. Pat. No. 2,412,167 issued to Minaker. 
Other prior art discloses flushing with inert gas the uppermost portion of 
containers after the containers have been filled with material, see U.S. 
Pat. No. 2,240,655 issued to Kronquest; U.S. Pat. No. 2,768,487 issued to 
Day et al. In addition, there is disclosed in the prior art means for 
flushing empty containers with inert gas, see U.S. Pat. No. 4,140,159 
issued to Demke. 
One object of this invention is to provide an apparatus which imparts a 
controlled environment, such as nitrogen or another inert gas, to one or 
more containers containing material at or near atmospheric pressure prior 
to sealing. This allows the use of less expensive container materials than 
used for the vacuum-packaging devices of the prior art. A related object 
is to provide an apparatus which achieves the desired near-total 
atmospheric exchange or control without at any time subjecting the 
container walls to a vacuum. 
Another object of the present invention is to provide such an apparatus for 
use in a continuous processing operation, which is mechanically simple, 
having few components and which is therefore economical and highly 
reliable. 
Another object is to provide such an apparatus which is adapted for use 
with specific sizes and configurations of jars and other containers, 
including containers of different heights. A further related object is to 
provide such a system adapted use with containers of specific diameters. 
These and other objects shall be apparent in light of the present 
specification. 
SUMMARY OF THE INVENTION 
In order to achieve a near complete substitution of an oxygen-containing or 
other environment within containers, means are provided for exposing the 
container to a source of environment, including means for applying the 
environment for a period of time. The environment is applied through a 
flow means which is connected to a plunger that connects to the container. 
The environment is applied to create a net circulation within the 
containers. This is accomplished by forming a seal on the top of each 
container with the plunger, and entering an environment such as nitrogen 
or another inert gas on one side of the container, while removing an 
environment (oxygen or air) on the other side by means of an escape 
orifice. The inert gas preferably passes through the product and sweeps 
down to the bottom of a container along one side, and then up and out 
through the other side. This circulation eventually forces substantially 
all of the original environment (e.g. the oxygen-containing environment) 
out of the container, replacing it with an environment substantially 
consisting of inert gas. The result is to substantially reduce the amount 
of oxygen in the container without requiring numerous processing steps or 
a vacuum. This embodiment of the invention provides a very efficient and 
effective system for removing substantially all of the atmosphere from the 
product container prior to sealing, an accomplishment which previously 
required vacuum or burdensome gas flushing tunnels.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, the plunger 140 includes a top plate 145 which may be 
constructed of metal, a middle layer 146 which may be constructed of 
plastic, and a base plate 147 preferably constructed of metal for 
engagement with the upper rim of the container 70. A piston 190 is 
attached to the plunger 140, such as by means of a rod-like protrusion 148 
projecting upward from the base plate 147 and into a hollow portion 170 in 
the bottom of the piston 190. The rod-like protrusion 148 is locked into 
the hollow portion 170 by means of locking the pin 174 passing through 
openings 171 in the wall 172 of the hollow portion 170, and an opening 173 
in the rod-like protrusion 148. Preferably, the openings 171 or the 
openings 173 are in the form of vertical slots in order to allow some lost 
motion biasing of the hollow portion 170 relative to the plunger 140 by 
means of a spring 178. 
Located above the spring 178 is a solid portion 179 telescopically engaging 
a second hollow portion 182 and a piston rod 184 and connected thereto 
using a pin 185 passing through openings 186 in the wall 183 of hollow 
portion 182 and through an opening 187 in the solid portion 179. The 
plurality of openings 186 allows adjustment of the piston 190 to different 
lengths by moving the position of the lower solid portion 179 relative to 
the piston rod 184. The plunger 140 thus is brought into contact proximity 
of the top of the container 70. 
It is understood that alternate means may similarly be used for attaching 
the plunger 140. Further, while it is desirable to provide for vertical 
movement of the plunger, such movement is not necessary. The plunger may 
be fixed. Other electrical, hydraulic or pneumatic means may be used for 
moving the plunger. 
Referring now to FIGS. 1, 2, 3 and 4, the optimum design for the plunger 
140 is illustrated for a system which a source of nitrogen is utilized to 
remove oxygen from a cylindrical container having about a four-inch 
diameter opening in the top and replace it with a substantially inert 
environment comprising nitrogen. This design is for a container containing 
loose food such as nuts, positioned inside a chamber having a volume of 
about 0.20 cubic foot, wherein the desired residual oxygen content in the 
containers is less than about 1.0% by volume of the total gas present in 
the container. 
The top plate 145, the middle layer 146 and the base plate 147 of the 
plunger 140 are held together in a sealing fashion by means of nut and 
bolt assemblies positioned at four openings 151, 152, 153 and 154 of each 
plunger plate. Each plate can be trapezoidal in shape in order to 
correspond to the cross-sectional shape of the individual chambers in the 
apparatus shown in the parent application Ser. No. 07/184,282, the 
disclosure of which has been incorporated herein by reference. 
Alternatively, the plates 145, 146 and 147 can be circular, as shown in 
FIGS. 2, 3 and 4, respectively, or can have another suitable shape. 
The top plate 145 and the bottom plate 147 are preferably constructed of 
metal and have thicknesses of about 0.187 inches. The middle layer 146 is 
preferably constructed of plastic and has a thickness of about 0.720 
inches. Other suitable materials and thicknesses may, of course, be 
utilized. 
Nitrogen enters the plunger 140 through passage 142 in the top plate 145 
which opens into a curved channel 200 in the middle layer 146. The channel 
200 has a width of about 0.375 inches, a depth of about 0.375 inches and a 
radius of curvature of about 1.75 inches. After entering the curved 
channel 200, the nitrogen passes into the container 70 through four 
openings 201, 202, 203 and 204, each having a diameter of about 0.156 
inches and passing through the floor of the curved channel 200 and through 
the bottom plate 147 of the plunger 140. Openings 202 and 203 are located 
about 10.degree. to the left and right of the center line 205 of the 
channel, while openings 201 and 204 are located about 17.degree. 
therefrom. 
The preferred flow rates for this application are less than about 12 cubic 
feet per minute of nitrogen. The optimum flow rate will vary to an extent 
depending upon the product for which oxygen removal is sought, the size 
and shape of the container and depending upon the speed and the number of 
plungers incorporated in the rotary configured machine. 
The plunger 140 may further comprise a screen positioned below the middle 
layer 146 in order to keep product from the container from entering the 
plunger 140 and clogging the passages. The openings may be enlarged for 
gentler gas flow or reduced in size to create higher velocity jets. 
Orifices and nozzles may be employed as well. Further, the environment 
openings may be inclined radially or circumferentially to create desired 
flow patterns in the container (for example, swirling or directing the 
flow against the container walls). 
The air within the container and excess nitrogen exit the container through 
an outlet curved channel 210 formed in the base plate 147 and leading into 
and encompassing outlet openings 211-219 formed in the middle layer. The 
outlet opening leads to a second channel 220 in the middle layer 146 and 
then through an outlet passage 144 formed in the top plate 145 which vents 
the air and excess nitrogen to the atmosphere. 
The curved channels have contours complementary to an opening in the 
container. When the plunger is sealed on the container opening the curved 
channels located on opposite sides of the plunger correspond substantially 
to the curvature of the container opening being purged such that all of 
the container wall and floor is subject to the purge. The curved channel 
210 increases the surface area of the screen reducing the ability of 
product material to clog in the outlet openings. Additional means of 
reducing potential clogging is accomplished by reversing the flow of gas 
to jet down through the curved channel and screen (inlet 144) via a 
reversing manifold system. This would be accomplished when the plunger is 
in a neutral position and not in contact with a container. The placement 
of the openings having a contour complementary to the opening of the 
container provide the most efficient means of purging the container of 
air. 
The nitrogen gas is able to substantially travel along the one wall of the 
container with fewer redirections than would be possible if the gas was 
jetted more towards the center of the container where the gas would be 
allowed to dissipate in more directions. 
It should be understood that the present invention may be embodied in other 
specified forms without departing from its spirit or essential 
characteristics. The present embodiments are, therefore, to be considered 
in all respects as illustrative and not restrictive. All changes which 
come within the meaning and range of the equivalents of the claims are 
therefore, intended to be embraced therein.