U.S. patent application number 10/636454 was filed with the patent office on 2004-02-19 for storage device utilizing zeolites to control gaseous content.
Invention is credited to Carlson, Peter, Kunstadt, Lawrence.
Application Number | 20040033162 10/636454 |
Document ID | / |
Family ID | 31720712 |
Filed Date | 2004-02-19 |
United States Patent
Application |
20040033162 |
Kind Code |
A1 |
Kunstadt, Lawrence ; et
al. |
February 19, 2004 |
Storage device utilizing zeolites to control gaseous content
Abstract
A storage device for the preservation of oxidizable materials
includes a storage chamber enclosing a storage space adapted to
receive oxidizable materials for storage therein. The storage
device also includes a zeolite chamber having a zeolite therein,
the zeolite chamber allowing at least one selected gas to pass
therethrough while inhibiting at least oxygen from passing
therethrough. The zeolite chamber is in fluid communication with
the storage chamber such that the at least one selected gas allowed
to pass through the zeolite chamber flows into the storage chamber.
An air mover feeds gases to the zeolite chamber, and the level of
oxygen within the storage chamber is reduced relative to the level
of oxygen in the atmosphere.
Inventors: |
Kunstadt, Lawrence;
(Ardsley, NY) ; Carlson, Peter; (Chevy Chase,
MD) |
Correspondence
Address: |
ST. ONGE STEWARD JOHNSTON & REENS, LLC
986 BEDFORD STREET
STAMFORD
CT
06905-5619
US
|
Family ID: |
31720712 |
Appl. No.: |
10/636454 |
Filed: |
August 7, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60404009 |
Aug 16, 2002 |
|
|
|
Current U.S.
Class: |
422/40 ; 422/243;
62/271; 62/78 |
Current CPC
Class: |
F25D 17/042 20130101;
A23L 3/3436 20130101 |
Class at
Publication: |
422/40 ; 62/78;
62/271; 422/243 |
International
Class: |
F24F 003/16 |
Claims
What is claimed is:
1. A storage device for the preservation of oxidizable materials
comprising: a storage chamber enclosing a storage space adapted to
receive oxidizable materials for storage therein; a zeolite chamber
having a zeolite therein, said zeolite chamber allowing at least
one selected gas to pass therethrough while inhibiting at least
oxygen from passing therethrough, said zeolite chamber in fluid
communication with said storage chamber such that the at least one
selected gas allowed to pass through said zeolite chamber flows
into said storage chamber; an air mover for feeding gases to said
zeolite chamber; and wherein the level of oxygen within said
storage chamber is reduced relative to the level of oxygen in the
atmosphere.
2. The storage device of claim 1 wherein said zeolite chamber
employs pressure swing absorption in order to allow the at least
one selected gas to pass therethrough while inhibiting at least
oxygen from passing therethrough.
3. The storage device of claim 1 further comprising a cooling
element for cooling the temperature within said storage chamber
below that of the ambient temperature surrounding said storage
device.
4. The storage device of claim 3 wherein said cooling element cools
the temperature within said storage chamber to a temperature within
a range from about 15.degree. F. to about 20.degree. F. below
normal room temperature.
5. The storage device of claim 3 wherein said cooling element
comprises a piezoelectric or Peltier module.
6. The storage device of claim 1 wherein the at least one selected
gas allowed to pass through said zeolite chamber comprises
nitrogen.
7. The storage device of claim 6 wherein the zeolite within said
zeolite chamber has an affinity for nitrogen.
8. The storage device of claim 1 wherein said zeolite chamber
comprises a vent for venting oxygen to the atmosphere.
9. The storage device of claim 1 further comprising a flow
controller valve which, in conjunction with said air mover,
selectively maintains a positive pressure within said zeolite
chamber.
10. The storage device of claim 9 wherein said flow controller
valve comprises a needle valve.
11. The storage device of claim 9 further comprising a gauge to
indicate a level of positive pressure within said zeolite
chamber.
12. The storage device of claim 1 further comprising a moisture
separator or filter to remove moisture from gases entering said
zeolite chamber.
13. The storage device of claim 1 wherein said air mover draws the
gases for feeding to said zeolite chamber from the atmosphere.
14. The storage device of claim 13 wherein said storage chamber
includes a vent to allow gases present therein, including oxygen
introduced when said storage chamber is opened to access objects
therein, to be forced out by substantially oxygen free gases passed
through said zeolite chamber.
15. The storage device of claim 14 wherein the vent of said storage
chamber comprises a seal around a door of said storage chamber
which allows gases to escape there around.
16. The storage device of claim 1 wherein the level of oxygen
within said storage chamber is maintained in a range of about 2% to
about 8%.
17. The storage device of claim 16 wherein the level of oxygen
within said storage chamber is maintained in a range of about 4% to
about 6%.
18. The storage device of claim 1 wherein said air mover comprises
a compressor.
19. A storage device for the preservation of oxidizable materials
comprising: a storage chamber enclosing a storage space adapted to
receive oxidizable materials for storage therein; a zeolite chamber
having a zeolite with an affinity for nitrogen therein, said
zeolite chamber employing pressure swing absorption to allow at
least nitrogen to pass therethrough while inhibiting at least
oxygen from passing therethrough, said zeolite chamber in fluid
communication with said storage chamber such that the at least
nitrogen allowed to pass through said zeolite chamber flows into
said storage chamber; a compressor for feeding gases to said
zeolite chamber; a piezoelectric or Peltier module cooling element
for cooling the temperature within said storage chamber below that
of the ambient temperature surrounding said storage device; and
wherein the level of oxygen within said storage chamber is reduced
relative to the level of oxygen in the atmosphere.
20. The storage device of claim 19 wherein said zeolite chamber
comprises a vent for venting oxygen to the atmosphere.
21. The storage device of claim 19 further comprising a flow
controller valve which, in conjunction with said compressor,
selectively maintains a positive pressure within said zeolite
chamber.
22. The storage device of claim 21 wherein said flow controller
valve comprises a needle valve.
23. The storage device of claim 21 further comprising a gauge to
indicate a level of positive pressure within said zeolite
chamber.
24. The storage device of claim 19 further comprising a moisture
separator or filter to remove moisture from gases entering said
zeolite chamber.
25. The storage device of claim 19 wherein said cooling element
cools the temperature within said storage chamber to a temperature
within a range from about 15.degree. F. to about 20.degree. F.
below normal room temperature.
26. The storage device of claim 19 wherein said compressor draws
the gases for feeding to said zeolite chamber from the
atmosphere.
27. The storage device of claim 26 wherein said storage chamber
includes a vent to allow gases present therein, including oxygen
introduced when said storage chamber is opened to access objects
therein, to be forced out by substantially oxygen free gases passed
through said zeolite chamber.
28. The storage device of claim 27 wherein the vent of said storage
chamber comprises a seal around a door of said storage chamber
which allows gases to escape therearound.
29. The storage device of claim 19 wherein the level of oxygen
within said storage chamber is maintained in a range of about 2% to
about 8%.
30. The storage device of claim 29 wherein the level of oxygen
within said storage chamber is maintained in a range of about 4% to
about 6%.
31. A method for storing and preserving oxidizable materials, said
method comprising the steps of: providing a storage chamber
enclosing a storage space adapted to receive oxidizable materials
for storage therein; forcing at least one selected gas to pass
through a zeolite chamber having a zeolite therein and into the
storage chamber while inhibiting at least oxygen from passing
through the zeolite chamber; and maintaining the level of oxygen
within the storage chamber at a level which is reduced relative to
the level of oxygen in the atmosphere.
32. The method of claim 31 wherein said forcing step comprises the
step of employing pressure swing absorption in order to force at
least one selected gas to pass through a zeolite chamber having a
zeolite therein and into the storage chamber while inhibiting at
least oxygen from passing through the zeolite chamber.
33. The method of claim 31 further comprising the step of cooling
the temperature within the storage chamber below that of the
ambient temperature surrounding the storage chamber.
34. The method of claim 33 wherein said cooling step comprises that
step of cooling the temperature within the storage chamber to a
temperature within a range from about 15.degree. F. to about
20.degree. F. below normal room temperature.
35. The method of claim 33 wherein said cooling step comprises that
step of providing a piezoelectric or Peltier module for cooling the
temperature within the storage chamber below that of the ambient
temperature surrounding the storage chamber.
36. The method of claim 31 further comprising the step of venting
the oxygen inhibited from passing through the zeolite chamber to
the atmosphere.
37. The method of claim 31 further comprising the step of
maintaining a positive pressure within the zeolite chamber.
38. The method of claim 31 wherein the at least one selected gas
forced to pass through the zeolite chamber comprises nitrogen.
39. The method of claim 31 wherein said maintaining the level of
oxygen step comprises the step of maintaining the level of oxygen
within the storage chamber within a range of from about 2% to about
8%.
40. The method of claim 39 wherein said maintaining the level of
oxygen step comprises the step of maintaining the level of oxygen
within the storage chamber within a range of from about 4% to about
6%.
41. A refrigerator which includes a storage chamber enclosing a
storage space adapted to receive oxidizable materials for storage
therein, said refrigerator comprising: a zeolite chamber having a
zeolite therein, said zeolite chamber allowing at least one
selected gas to pass therethrough while inhibiting at least oxygen
from passing therethrough, said zeolite chamber in fluid
communication with the storage space such that the at least one
selected gas allowed to pass through said zeolite chamber flows
into the storage space; an air mover for feeding gases to said
zeolite chamber; and wherein the level of oxygen within the storage
space is reduced relative to the level of oxygen in the
atmosphere.
42. The refrigerator of claim 41 wherein said zeolite chamber
employs pressure swing absorption in order to allow the at least
one selected gas to pass therethrough while inhibiting at least
oxygen from passing therethrough.
43. The refrigerator of claim 41 wherein said air mover comprises a
compressor.
Description
RELATED APPLICATIONS
[0001] This patent application claims the benefit of, under Title
35, United States Code, Section 119(e), U.S. Provisional Patent
Application No. 60/404,009, filed Aug. 16, 2002.
FIELD OF THE INVENTION
[0002] The present invention relates to a storage device, and more
specifically to a long-term storage device for oxidizable materials
which controls the gaseous content of a storage volume of the
device in order to prolong storage life, allow storage of currently
difficult-to-store materials and to inhibit the ripening and/or
deterioration of certain foods.
BACKGROUND OF THE INVENTION
[0003] Refrigerated devices are well known and widely utilized to
increase the storage life of items to be stored, such as food
items. As an example, a refrigerator commonly used in most
households in the United States increases the storage life of many
foods by maintaining the temperature well below room temperature,
thereby slowing the natural ripening and oxidation processes.
However, such devices suffer from a number of disadvantages,
including complexity, weight and cost.
[0004] Moreover, devices which rely solely upon refrigeration can
be noisy and generate a great amount of heat, which may be
undesirable in many circumstances. Furthermore, refrigeration
devices are generally not energy efficient, and thus such devices
are typically costly to operate and environmentally unfriendly.
Furthermore, refrigeration devices may not be appropriate for
storing all food items (e.g., apples may lose their taste when
cold, bananas may turn black, etc.). Another problem with
refrigeration devices is that they may not be appropriate for
storing many non-food items (e.g., documents, stamps, coins, etc.)
due to moisture problems.
[0005] Another type of storage device which has been developed is a
vacuum storage device, which operates by creating a vacuum within a
storage volume of the device in order to remove oxygen therefrom,
and extend the storage life of oxidizable materials. Although such
devices obviate some of the disadvantages of refrigeration devices
(i.e., the problems associated with storing certain food items in a
cold environment and the moisture problems), vacuum devices do not
remedy a number of the other problems. Vacuum storage devices are
typically even more complex, heavy and costly to produce than
refrigeration devices, which is why such vacuum devices are
typically used only in industrial settings. These devices are
typically large and may pose a safety problem, as it has been known
that persons may become trapped within such devices, and be injured
or killed because of the vacuum created therein.
[0006] Furthermore, the vacuum pumps used with vacuum storage
devices can be noisy and are generally not energy efficient,
thereby making vacuum storage devices costly to operate and
environmentally unfriendly. Moreover, vacuum storage devices suffer
from a number of additional disadvantages. In addition to requiring
a costly vacuum pump, the storage volume itself is also costly.
This is true because, due to the vacuum created, a structurally
heavy storage volume is required so as to inhibit implosion or
collapsing thereof due to the vacuum formed therein. Moreover, a
complex and expensive sealing means is required so that the storage
volume can hold a vacuum. Moreover, despite the precautions taken,
there is a very real possibility that implosion may occur and/or
that a vacuum may not be held.
[0007] Yet another type of storage device which has been developed
is an inert gas pumping system. In these devices, an inert gas
environment is artificially maintained within a storage volume by
pumping an inert gas, such as nitrogen, into the storage volume,
thereby displacing the normal atmospheric content (including
oxygen) to maintain and prolong the storage life of oxidizable
items stored therein. However, these devices are typically even
more costly and complex than refrigeration and vacuum systems, and
are therefore generally used only to store rare documents, stamps,
coins, and/or other valuable materials. A further disadvantage of
these types of systems is that it is necessary to provide, and to
replace on a regular basis, cylinders of inert gas, which can be
costly and burdensome, and which renders such devices appropriate
only for large-scale industrial use (as opposed to home use).
[0008] Still another type of storage device includes a storage
chamber enclosing a storage space where oxidizable materials may be
placed and a differentially permeable membrane. The differentially
permeable membrane allows at least one selected gas to pass
therethrough while inhibiting at least oxygen from passing
therethrough. The differentially permeable membrane is in fluid
communication with the storage chamber such that the at least one
selected gas is allowed to pass through the differentially
permeable membrane flows into the storage chamber. An air mover,
preferably a compressor, feeds gases to the differentially
permeable membrane. Such devices may not provide adequate
efficiency at a reasonable cost in certain situations.
[0009] What is desired, therefore, is a storage device for
oxidizable materials which controls the gaseous content of a
storage volume of the device in order to prolong storage life, to
allow storage of currently difficult-to-store materials, to allow
storage of non-refrigeratable foods and to inhibit the ripening
and/or deterioration of certain foods without adversely affecting
flavor, which is relatively simple in design, lightweight and
inexpensive to produce, which operates quietly and does not
generate a great amount of heat, which is appropriate for storing
substantially all oxidizable food items and non-food items, which
is energy efficient and therefore relatively inexpensive to operate
and environmentally friendly, which does not risk implosion, and
which does not require servicing and/or the replacement of
components on a regular basis.
SUMMARY OF THE INVENTION
[0010] Accordingly, it is an object of the present invention to
provide a storage device for oxidizable materials which controls
the gaseous content of a storage volume of the device in order to
prolong storage life, to allow storage of currently
difficult-to-store materials, to allow storage of
non-refrigeratable foods and to inhibit the ripening and/or
deterioration of certain foods without adversely affecting
flavor.
[0011] Another object of the present invention is to provide a
storage device for oxidizable materials having the above
characteristics and which is relatively simple in design,
lightweight and inexpensive to produce.
[0012] A further object of the present invention is to provide a
storage device for oxidizable materials having the above
characteristics and which operates quietly and does not generate a
great amount of heat.
[0013] Still another object of the present invention is to provide
a storage device for oxidizable materials having the above
characteristics and which is appropriate for storing substantially
all oxidizable food items and non-food items.
[0014] Yet a further object of the present invention is to provide
a storage device for oxidizable materials having the above
characteristics and which is energy efficient and therefore
relatively inexpensive to operate and environmentally friendly.
[0015] Still yet a further object of the present invention is to
provide a storage device for oxidizable materials having the above
characteristics and which does not risk implosion.
[0016] Yet another object of the present invention is to provide a
storage device for oxidizable materials having the above
characteristics and which does not require servicing and/or the
replacement of components on a regular basis.
[0017] These and other objects of the present invention are
achieved in one embodiment by the provision of a storage device for
the preservation of oxidizable materials including a storage
chamber enclosing a storage space adapted to receive oxidizable
materials for storage therein. The storage device also includes a
zeolite chamber having a zeolite therein, the zeolite chamber
allowing at least one selected gas to pass therethrough while
inhibiting at least oxygen from passing therethrough. The zeolite
chamber is in fluid communication with the storage chamber such
that the at least one selected gas allowed to pass through the
zeolite chamber flows into the storage chamber. An air mover feeds
gases to the zeolite chamber, and the level of oxygen within the
storage chamber is reduced relative to the level of oxygen in the
atmosphere.
[0018] In some embodiments, the zeolite chamber employs pressure
swing absorption in order to allow the at least one selected gas to
pass therethrough while inhibiting at least oxygen from passing
therethrough. In some embodiments, a cooling element is provided
for cooling the temperature within the storage chamber below that
of the ambient temperature surrounding the storage device. In
certain of these embodiments, the cooling element cools the
temperature within the storage chamber to a temperature within a
range from about 15.degree. F. to about 20.degree. F. below normal
room temperature. In certain embodiments, the cooling element
comprises a piezoelectric or Peltier module.
[0019] In some embodiments, the at least one selected gas allowed
to pass through the zeolite chamber comprises nitrogen. In certain
of these embodiments, the zeolite within the zeolite chamber has an
affinity for nitrogen. In some embodiments, the zeolite chamber
comprises a vent for venting oxygen to the atmosphere. A flow
controller valve may be provided which, in conjunction with the air
mover, selectively maintains a positive pressure within the zeolite
chamber. In certain of these embodiments, the flow controller valve
comprises a needle valve. In certain embodiments, a gauge is
provided to indicate a level of positive pressure within the
zeolite chamber.
[0020] In some embodiments, a moisture separator or filter may be
provided to remove moisture from gases entering the zeolite
chamber. In some embodiments, the air mover draws the gases for
feeding to the zeolite chamber from the atmosphere. In certain of
these embodiments, the storage chamber includes a vent to allow
gases present therein, including oxygen introduced when the storage
chamber is opened to access objects therein, to be forced out by
substantially oxygen free gases passed through the zeolite chamber.
In certain embodiments, the vent of the storage chamber comprises a
seal around a door of the storage chamber which allows gases to
escape therearound.
[0021] In some embodiments, the level of oxygen within the storage
chamber is maintained in a range of about 2% to about 8%. In
certain of these embodiments, the level of oxygen within the
storage chamber is maintained in a range of about 4% to about 6%.
In some embodiments, the air mover comprises a compressor.
[0022] In another embodiment of the present invention, a storage
device for the preservation of oxidizable materials includes a
storage chamber enclosing a storage space adapted to receive
oxidizable materials for storage therein. A zeolite chamber, having
a zeolite with an affinity for nitrogen therein, employs pressure
swing absorption to allow at least nitrogen to pass therethrough
while inhibiting at least oxygen from passing therethrough. The
zeolite chamber is in fluid communication with the storage chamber
such that the at least nitrogen allowed to pass through the zeolite
chamber flows into the storage chamber. A compressor feeds gases to
the zeolite chamber. A piezoelectric or Peltier module cooling
element is provided for cooling the temperature within the storage
chamber below that of the ambient temperature surrounding the
storage device, and the level of oxygen within the storage chamber
is reduced relative to the level of oxygen in the atmosphere.
[0023] In some embodiments, the zeolite chamber comprises a vent
for venting oxygen to the atmosphere. In some embodiments, a flow
controller valve is provided which, in conjunction with the
compressor, selectively maintains a positive pressure within the
zeolite chamber. In certain of these embodiments, the flow
controller valve comprises a needle valve, and in certain of these
embodiments, a gauge is provided to indicate a level of positive
pressure within the zeolite chamber.
[0024] In some embodiments, a moisture separator or filter is
provided to remove moisture from gases entering the zeolite
chamber. In some embodiments, the cooling element cools the
temperature within the storage chamber to a temperature within a
range from about 15.degree. F. to about 20.degree. F. below normal
room temperature. In some embodiments, the compressor draws the
gases for feeding to the zeolite chamber from the atmosphere.
[0025] In certain embodiments, the storage chamber includes a vent
to allow gases present therein, including oxygen introduced when
the storage chamber is opened to access objects therein, to be
forced out by substantially oxygen free gases passed through the
zeolite chamber. In certain of these embodiments, the vent of the
storage chamber comprises a seal around a door of the storage
chamber which allows gases to escape therearound.
[0026] In some embodiments, the level of oxygen within the storage
chamber is maintained in a range of about 2% to about 8%. In
certain of these embodiments, the level of oxygen within the
storage chamber is maintained in a range of about 4% to about
6%.
[0027] In another embodiment of the present invention a method for
storing and preserving oxidizable materials is provided. The
inventive method involves providing a storage chamber enclosing a
storage space adapted to receive oxidizable materials for storage
therein. At least one selected gas is forced to pass through a
zeolite chamber having a zeolite therein and into the storage
chamber while inhibiting at least oxygen from passing through the
zeolite chamber, and the level of oxygen within the storage chamber
is maintained at a level which is reduced relative to the level of
oxygen in the atmosphere.
[0028] In some embodiments, pressure swing absorption is employed
in order to force the at least one selected gas to pass through a
zeolite chamber having a zeolite therein and into the storage
chamber while inhibiting at least oxygen from passing through the
zeolite chamber. In some embodiments, the temperature within the
storage chamber is cooled below that of the ambient temperature
surrounding the storage chamber. In certain of these embodiments,
the cooling step comprises that step of cooling the temperature
within the storage chamber to a temperature within a range from
about 15.degree. F. to about 20.degree. F. below normal room
temperature. In certain embodiments, the cooling step comprises
that step of providing a piezoelectric or Peltier module for
cooling the temperature within the storage chamber below that of
the ambient temperature surrounding the storage chamber.
[0029] In some embodiments, the oxygen inhibited from passing
through the zeolite chamber is vented to the atmosphere. In some
embodiments, a positive pressure is maintained within the zeolite
chamber. In certain embodiments, the at least one selected gas
forced to pass through the zeolite chamber comprises nitrogen.
[0030] In some embodiments, the maintaining the level of oxygen
step comprises the step of maintaining the level of oxygen within
the storage chamber within a range of from about 2% to about 8%. In
certain of these embodiments, the maintaining the level of oxygen
step comprises the step of maintaining the level of oxygen within
the storage chamber within a range of from about 4% to about
6%.
[0031] In another embodiment of the present invention, a
refrigerator includes a storage chamber enclosing a storage space
adapted to receive oxidizable materials for storage therein. The
refrigerator comprises a zeolite chamber having a zeolite therein,
the zeolite chamber allowing at least one selected gas to pass
therethrough while inhibiting at least oxygen from passing
therethrough. The zeolite chamber is in fluid communication with
the storage space such that the at least one selected gas allowed
to pass through the zeolite chamber flows into the storage space.
An air mover feeds gases to the zeolite chamber, and the level of
oxygen within the storage space is reduced relative to the level of
oxygen in the atmosphere.
[0032] In some embodiments, the zeolite chamber employs pressure
swing absorption in order to allow the at least one selected gas to
pass therethrough while inhibiting at least oxygen from passing
therethrough. In certain embodiments, the air mover comprises a
compressor.
[0033] The invention and its particular features and advantages
will become more apparent from the following detailed description
considered with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a schematic view of an embodiment of a storage
device for oxidizable materials in accordance with the present
invention; and
[0035] FIG. 2 a schematic view of a refrigerator including a
storage device for oxidizable materials in accordance with the
present invention.
DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION
[0036] Referring first to FIG. 1, a storage device 10 for
oxidizable materials is shown. Storage device 10 includes a storage
chamber 12, which may be of substantially any shape, for example,
square, rectangular, cylindrical, trapezoidal, cookie jar-shaped,
thermos-shaped, etc., by varying the configuration of its walls, as
should be readily apparent to those skilled in the art. A
rectangular shape, however, is preferred for ease of construction
and use. Storage chamber 12 provides a convenient place to store
oxidizable objects.
[0037] Access to the interior of storage chamber 12 is provided
through a door utilizing hinges and a handle mechanism which is
known in the art. As such, and because such door and handle means
are known in the art, a detailed description thereof is not
presented herein. However, it should be noted that it is
preferable, although not necessary, that the door comprise
substantially an entire side of storage chamber 12 and that the
hinges are positioned accordingly, such as is the case with a
typical microwave oven. This arrangement is preferable so as to
allow unrestricted access to the interior of storage chamber 12,
and to allow off-gases (which may occur particularly when fresh
fruits or vegetables are stored) to exit storage chamber 12 through
the door when opened.
[0038] A gauge or oxygen meter may optionally be provided to
monitor the percentage of oxygen content within storage chamber 12.
Although not required, such a gauge may allow a user or
manufacturer to verify that the oxygen content of storage chamber
12 is within a desired range.
[0039] Storage device 10 also includes an air mover 14 to draw air
from the atmosphere and feed it to a zeolite chamber 16. Air mover
14 preferably comprises a compressor, but may also comprise a fan,
a pump, a blower or any other device for feeding various gases.
[0040] Zeolite chamber 16 may take many forms so long as it
contains zeolites. Zeolites are microporous crystalline solids with
well-defined structures. Generally they contain silicon, aluminium
and oxygen in their framework and cations, water and/or other
molecules Within their pores. Many occur naturally as minerals, and
are extensively mined in many parts of the world. Others are
synthetic, and are made commercially for specific uses, or produced
by research scientists trying to understand more about their
chemistry. What is of particular importance here is that certain
zeolites exhibit an affinity for one or more particular gases,
effectively acting as sieves capturing these gases as a combination
of gasses pass adjacent thereto. Zeolites with an affinity to
substantially any gas other than oxygen may be employed in zeolite
chamber 16. Because of the abundance of nitrogen in the atmosphere,
a zeolite with an affinity to nitrogen would be a preferable
choice.
[0041] Zeolite chamber 16 is configured so as to allow for pressure
swing absorption of nitrogen therein. As pressure swing absorption
is known in the zeolite art, only a simple illustration is provided
herein. In this example, zeolite chamber 16 includes an inlet 18
for receiving gases from air mover 14 and two outlets 20, 22. One
of outlets 20 is in communication with atmosphere, while the other
of outlets 22 is in communication with storage chamber 12. Outlets
20, 22 each have a valve 24, 26 therein for selectively opening or
closing each outlet 20, 22. Outlet 22 in communication with storage
chamber 12 may also include a flow controller valve 28, such as a
needle valve, to maintain, in conjunction with air mover 14, a
positive pressure within zeolite chamber 16 when such a positive
pressure is necessary to free captured nitrogen from the zeolites
within zeolite chamber 16, as more fully described below. A gauge
30 or the like may be provided to ensure that the proper positive
pressure required by the zeolites in zeolite chamber 16 is being
maintained.
[0042] In operation, valve 26 in outlet 22 which is in
communication with storage chamber 12 is closed, and valve 24 in
outlet 20 which is in communication with atmosphere is opened. Air
mover 14 causes gases (containing at least oxygen and nitrogen) to
pass through zeolite chamber 16. The zeolites in zeolite chamber,
having an affinity for nitrogen, capture nitrogen from the stream
of gases passing therethrough before the gases (including
substantially all of the oxygen) are vented to atmosphere. After a
predetermined time period when a sufficient amount of nitrogen has
been captured by the zeolites in zeolite chamber, valve 24 in
outlet 20 which is in communication with atmosphere is closed and
valve 26 in outlet 22 which is in communication with storage
chamber 12 is opened. The positive pressure in zeolite chamber 16
generated by air mover 14 and flow controller valve 28 causes the
nitrogen captured by the zeolites to be freed and to flow into
storage chamber 12. As such, the gases entering storage chamber 12
contain substantially more nitrogen and substantially less oxygen
than normal atmosphere. After a predetermined time period when a
large amount of the nitrogen is freed from the zeolites, valve 24
in outlet 20 which is in communication with atmosphere is re-opened
and valve 26 in outlet 22 which is in communication with storage
chamber 12 is re-closed before a substantial amount of oxygen can
escape through outlet 22 in communication with storage chamber 12.
This process is repeated over and over so as to maintain a gas
content in storage chamber with a substantially lower concentration
of oxygen as compared to atmosphere.
[0043] Storage chamber 12 includes a vent 32 or the like to allow
gases present therein, including oxygen which may be introduced
when storage chamber 12 is opened to access objects therein, to be
forced out by the substantially oxygen free gases passed through
zeolite chamber 16. In one preferred embodiment, vent 32 may simply
comprise a seal around a door of storage chamber 12 which allows
gases to escape therearound.
[0044] Storage device 10 may include various additional air
treatment devices when desirable depending upon the objects to be
stored. For example, a moisture separator or filter, such as a
water absorbent 34, may be provided to remove moisture from gases
in the system. In addition, a heating or cooling element 36 may be
provided is desired to adjust the temperature of the gases in the
system. In this manner, storage device 10 or a section thereof may
be refrigerated if such is desired. A heating, or more preferably,
cooling element 40, such as a thermoelectric or Peltier module, may
be provided in or around storage chamber 12. Although such cooling
elements are not generally as effective as traditional
refrigeration systems, they are sufficient here, since only a small
temperature decrease is necessary, and since they are much less
expensive to manufacture and operate.
[0045] By employing the above-described storage device, the
atmosphere within storage chamber 12 may be controlled to replace
normal atmospheric content of gas (i.e., approximately 80% nitrogen
and 20% oxygen) with an atmosphere with considerably less oxygen.
It has been found that that providing an atmosphere within storage
chamber 12 wherein the content of oxygen is between 2% and 8% is
desirable. This is true because, as will be understood by those
skilled in the art, there are generally three processes of
deterioration which adversely affect stored materials: (i)
oxidation, (ii) enzymatic deterioration, and (iii) microbial
contamination. With respect to the first two of these processes, it
is generally desirable to maintain as low an oxygen content as
possible (i.e., the closer the oxygen content to 0% the better).
However, with respect to microbial contamination, some types of
bacteria (i.e., anaerobic bacteria) are known to flourish in
substantially oxygen-free environments. Thus, maintaining an oxygen
content of less than approximately 2% may be undesirable. It has
also been found that the above-referenced deterioration processes
are slowed or halted only in environments having oxygen contents of
approximately 8% or less. Thus, the preferred range for oxygen
content within storage chamber 12 is from about 2% to about 8%. As
will also be recognized by those skilled in the art, the ideal
oxygen content may vary depending upon the objects expected to be
stored therein. However, it is often the case that various objects
will be stored together, each of which has its own ideal oxygen
content associated therewith. For example, when various fruits,
vegetables and other food materials are being stored together, an
oxygen content in the most preferred range of from about 4% to
about 6% provides acceptable results.
[0046] It should be understood that a storage device 10 in
accordance with the present invention may comprise a stand-alone
device. If desired, such a storage device may be portable, and may
be powered by a self-sustained power supply, such as by batteries,
rechargeable or conventional. It should also be understood that, as
schematically illustrated in FIG. 2, storage device 10 may be
incorporated into a larger device, such as a refrigerator 38. In
such a case, storage device 10 may be used instead of or in
addition to various fruit/vegetable and/or crisper drawers as are
conventional in known refrigerator designs. It should be further
understood that storage device 10 may be used in conjunction with
other devices which control the gaseous content within a chamber.
For example, system 10 may form a part of a larger system which
employs a selectively permeable membrane in addition to zeolites in
order to control the gaseous content within a chamber.
[0047] The present invention, therefore, provides a storage device
for oxidizable materials which controls the gaseous content of a
storage volume of the device in order to prolong storage life, to
allow storage of currently difficult-to-store materials, to allow
storage of non-refrigeratable foods and to inhibit the ripening
and/or deterioration of certain foods without adversely affecting
flavor, which is relatively simple in design, lightweight and
inexpensive to produce, which operates quietly and does not
generate a great amount of heat, which is appropriate for storing
substantially all oxidizable food items and non-food items, which
is energy efficient and therefore relatively inexpensive to operate
and environmentally friendly, which does not risk implosion, and
which does not require servicing and/or the replacement of
components on a regular basis.
[0048] Although the invention has been described with reference to
a particular arrangement of parts, features and the like, these are
not intended to exhaust all possible arrangements or features, and
indeed many other modifications and variations will be
ascertainable to those of skill in the art.
* * * * *