U.S. patent application number 12/941111 was filed with the patent office on 2011-12-29 for insulated chamber with phase change material.
This patent application is currently assigned to CARON PRODUCTS AND SERVICES, INC.. Invention is credited to MILTON F. BAKER, DALE C. BARNETT, ROBERT W. DOTTERER, DAVID N. FIGEL, STEPHEN C. KEISER.
Application Number | 20110315783 12/941111 |
Document ID | / |
Family ID | 45351601 |
Filed Date | 2011-12-29 |
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United States Patent
Application |
20110315783 |
Kind Code |
A1 |
BAKER; MILTON F. ; et
al. |
December 29, 2011 |
INSULATED CHAMBER WITH PHASE CHANGE MATERIAL
Abstract
An insulated chamber having an interior chamber for storing
items therein includes a phase change material to facilitate
controlling the temperature of the interior chamber and the items.
A heating device or cooling device may be used to melt or freeze
the phase change material, which may be in various locations such
as the walls of the chamber or packets which may serve as shelves
and may be removable from the interior chamber with the items
thereon. The packets may have recesses for receiving the items. The
phase change material may be within capsules which may be within a
liquid or a solid matrix. Controls may be provided to control
humidity and carbon dioxide within the interior chamber.
Inventors: |
BAKER; MILTON F.; (VINCENT,
OH) ; BARNETT; DALE C.; (MARIETTA, OH) ;
DOTTERER; ROBERT W.; (SARDIS, OH) ; FIGEL; DAVID
N.; (CALDWELL, OH) ; KEISER; STEPHEN C.;
(VIENNA, WV) |
Assignee: |
CARON PRODUCTS AND SERVICES,
INC.
MARIETTA
OH
|
Family ID: |
45351601 |
Appl. No.: |
12/941111 |
Filed: |
November 8, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61359143 |
Jun 28, 2010 |
|
|
|
Current U.S.
Class: |
236/3 ; 236/4;
236/44A |
Current CPC
Class: |
B01L 2300/043 20130101;
B01L 2300/1855 20130101; C12M 41/14 20130101; B01L 1/025 20130101;
B01L 2300/1844 20130101; Y02E 60/147 20130101; Y02E 60/14 20130101;
B01L 2300/1805 20130101; F24F 5/0021 20130101; B01L 7/52 20130101;
B01L 2300/1894 20130101; B01L 2300/10 20130101; B01L 2300/185
20130101; F25D 31/00 20130101; B01L 2300/1883 20130101 |
Class at
Publication: |
236/3 ; 236/4;
236/44.A |
International
Class: |
B01L 7/00 20060101
B01L007/00; F24F 3/14 20060101 F24F003/14 |
Claims
1. An apparatus comprising: a container defining a storage interior
chamber adapted to receive therein a storage item; a first phase
change material adjacent the interior chamber and having a first
melting or freezing phase change temperature; and a
temperature-altering device adjacent the first phase change
material and capable of causing the first phase change material to
reach the first melting or freezing phase change temperature.
2. The apparatus of claim 1 wherein the temperature-altering device
is electrically powered.
3. The apparatus of claim 1 wherein the temperature-altering device
comprises a heating device.
4. The apparatus of claim 1 wherein the temperature-altering device
comprises a cooling device.
5. The apparatus of claim 1 further comprising a sidewall of the
container comprising a layer which includes the first phase change
material and an inner layer between the layer of the first phase
change material and the interior chamber.
6. The apparatus of claim 5 wherein the sidewall comprises a layer
of thermal insulation; and the layer of the first phase change
material is between the layer of thermal insulation and inner
layer.
7. The apparatus of claim 1 further comprising a sidewall of the
container which defines a sidewall interior chamber; and wherein
the first phase change material is inside the sidewall interior
chamber.
8. The apparatus of claim 7 further comprising a layer of thermal
insulation within the sidewall interior chamber.
9. The apparatus of claim 8 further comprising a metal inner layer
of the sidewall which bounds the storage interior chamber.
10. The apparatus of claim 7 further comprising a metal inner layer
of the sidewall which bounds the storage interior chamber.
11. The apparatus of claim 7 further comprising a liquid in the
sidewall interior chamber; and a plurality of capsules in the
sidewall interior chamber each containing a portion of the phase
change material.
12. The apparatus of claim 1 further comprising a plurality of
capsules each containing a portion of the phase change material;
and a solid matrix in which the capsules are embedded.
13. The apparatus of claim 1 further comprising a door which is
mounted on the container, is movable between open and closed
positions, and comprises the phase change material.
14. The apparatus of claim 1 further comprising a shelf which
comprises the phase change material and which is movable between a
first position inside the interior chamber and a second position
outside the interior chamber.
15. The apparatus of claim 14 in combination with the storage item;
and wherein the shelf and storage item are movable together between
the first and second positions.
16. The apparatus of claim 1 further comprising a shelf which
comprises the phase change material and is inside the interior
chamber; and a recess which is formed in the shelf and adapted to
receive therein the storage item.
17. The apparatus of claim 1 further comprising a packet comprising
a metal skin defining a packet interior chamber; and wherein the
phase change material is inside the packet interior chamber; and
the packet is insertable into and removable from the storage
interior chamber.
18. The apparatus of claim 17 further comprising an outer surface
on the metal skin; and a storage item-receiving recess which is
formed in the skin, extends inwardly from the outer surface and is
adapted to receive therein the storage item.
19. The apparatus of claim 1 further comprising a second phase
change material adjacent the interior chamber and having a second
melting or freezing phase change temperature which is different
than the first melting or freezing phase change temperature; and a
temperature-altering device adjacent the second phase change
material and capable of causing the second phase change material to
reach the second melting or freezing phase change temperature.
20. The apparatus of claim 1 further comprising a fan in
communication with the storage interior chamber; a humidity control
unit operatively connected to the storage interior chamber; and a
carbon dioxide control unit operatively connected to the storage
interior chamber.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. Provisional
Application Ser. No. 61/359,143 filed Jun. 28, 2010; the disclosure
of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to insulated
chambers such as incubators, environmental chambers, freezers,
refrigerators and ovens. More particularly, the present invention
relates to an insulated chamber in which a phase change material
enhances temperature control.
[0004] 2. Background Information
[0005] Insulated chambers may be used for a variety of purposes.
For instance, such chambers may include incubators, environmental
chambers, freezers, refrigerators and ovens. Incubators are
typically used for growing cultures in a controlled environment,
wherein temperature, humidity, and atmospheric gas concentration
are maintained at selected levels. For certain applications it is
highly desirable to have both temperature and gas concentrations
maintained within strict tolerances while still allowing easy
access to the incubator chamber for adding or removing items to and
from the chamber or for inspecting the contents of the chamber.
Control of environmental variables is desirable to maintain
accuracy and reproducibility of incubation results. Typical
incubators have used either open-coil heaters within the incubator
chamber or water jackets surrounding the incubator chamber.
However, while such configurations can be effective in heating an
incubator, they do not necessarily provide as strict a control on
the incubator temperature as is desirable for consistent
results.
[0006] Conventional air heater type incubators lack the temperature
stability of the water jacket type. Water-jacketed incubators
maintain temperature by surrounding the interior chamber with
heated water in a separate compartment. The water is heated and
circulates around the inner chamber via natural convection. The
heat from the water radiates to the interior chamber to maintain a
substantially constant temperature inside. Water is an effective
thermal insulator and the water-jacket system is considered a more
reliable method of heating in case of a power outage. In the wake
of a power failure, a water-jacketed incubator will hold a set
temperature inside the chamber 4-5 times longer than a
radiant-walled unit.
[0007] Radiant-walled incubators heat the interior chamber using
heaters mounted in the surrounding cavity that radiate heat through
to the inside chamber. A radiant-walled heating system allows for
quick recovery of temperature following door openings or changes in
temperature settings. Radiant-walled heating systems are also more
simplified for the user, not requiring filling, monitoring, and
emptying water in the water jacket.
[0008] A fan may be mounted outside of the culturing area to help
to circulate the air inside the chamber without disturbing
cultures. This gentle circulation helps maintain a consistent
temperature throughout the chamber and speeds recovery of internal
temperature as well as CO.sub.2 and humidity levels following door
openings.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention provides an apparatus comprising: a
container defining a storage interior chamber adapted to receive
therein a storage item; a first phase change material adjacent the
interior chamber and having a first melting or freezing phase
change temperature; and a temperature-altering device adjacent the
first phase change material and capable of causing the first phase
change material to reach the first melting or freezing phase change
temperature.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0010] A preferred embodiment of the invention, illustrated of the
best mode in which Applicant contemplates applying the principles,
is set forth in the following description and is shown in the
drawings and is particularly and distinctly pointed out and set
forth in the appended claims.
[0011] FIG. 1 is a front elevational view of a first embodiment of
the insulated chamber of the present invention with portions shown
diagrammatically.
[0012] FIG. 2 is a sectional view taken on Line 2-2 of FIG. 1.
[0013] FIG. 3 is a sectional view taken on Line 3-3 of FIG. 2.
[0014] FIG. 4 is a sectional view taken on Line 4-4 of FIG. 2.
[0015] FIG. 5 is similar to FIG. 2 and is a sectional view of a
second embodiment of the chamber of the present invention.
[0016] FIG. 6 is a perspective view with portions cut away of the
removable and repositionable phase change material packet or wall
of the present invention.
[0017] FIG. 7 is a sectional view similar to FIG. 2 of a third
embodiment of the chamber of the present invention utilizing the
phase change material packets.
[0018] FIG. 8 is a sectional view similar to FIG. 7 of a fourth
embodiment of the present invention also utilizing the phase change
packets.
[0019] FIG. 9 is a sectional view similar to FIG. 2 of a fifth
embodiment of the chamber of the present invention utilizing a
heating element between the insulation and phase change
material.
[0020] FIG. 10 is a sectional view similar to FIG. 9 of a sixth
embodiment of the chamber of the present invention utilizing a
heating element between the phase change material and the inner
layer of the skin.
[0021] FIG. 11 is a sectional view similar to FIG. 5 of a seventh
embodiment of the chamber of the present invention wherein the
phase change material is contained within numerous encapsulated
pellets which are within a liquid medium.
[0022] FIG. 12 is a sectional view of one of the encapsulated
pellets.
[0023] FIG. 13 is a sectional view similar to FIG. 12 of an eighth
embodiment of the chamber of the present invention showing the
phase change material within encapsulated pellets which are
embedded in a solid matrix.
[0024] FIG. 14 is a perspective view of a PCM packet or shelf
having recesses formed therein for receiving respective storage
items.
[0025] FIG. 14A is a sectional view taken on line 14A-14A of FIG.
14.
[0026] FIG. 15 is a sectional view similar to FIG. 7 of a ninth
embodiment of the chamber of the present invention using the PCM
packets or shelves shown in FIG. 14.
[0027] FIG. 16 is a sectional view similar to FIG. 15 with the door
removed and portions cut away to illustrate the use of the PCM
packets or shelves inside and outside of the chamber.
[0028] FIG. 17 is a flow chart illustrating various methods of the
present invention. Similar numbers refer to similar parts
throughout the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0029] A first embodiment of the insulated enclosure or chamber of
the present invention is shown generally at 1 in FIG. 1, with
additional embodiments shown generally at 1A in FIG. 5, at 1B in
FIG. 7, at 1C in FIG. 8, at 1D in FIG. 9, at 1E in FIG. 10, at 1F
in FIG. 11, at 1G in FIG. 13, and at 1H in FIG. 15. Chamber 1 is
configured to serve as an incubator, environmental chamber, oven,
refrigerator or freezer. Chamber 1 includes a main body or
container 3, a storage interior chamber 4 defined by container 3, a
door 5 and a control assembly 7 secured to and seated atop
container 3. Container 3 in the exemplary embodiment is in the form
of a five-sided or five-walled box-like structure wherein the
forward terminal ends of four of these walls define an entrance
opening 6 (FIG. 2) of interior chamber 4. Upper and chamber 4.
Upper and lower horizontal shelves 2 are disposed within interior
chamber 4 extending between three of the walls of container 3 and
suitably supported therein for supporting thereon one or more
storage items 40 (dashed lines) to be stored in interior chamber 4
over a duration typically measured in hours, days, or weeks.
Storage item 40 may, for example, be one or more petri dishes or
other containers for growing cultures or for supporting other items
which need incubation or heating in a controlled manner. Storage
item 40 may also include the contents of a dish or container, such
as a culture, and may include other components, some of which are
discussed in greater detail further below. Item 40 may also be
cooled in a controlled manner and frozen if desired. Insulated
chamber is configured to heat and/or cool item 40 and/or to
maintain item 40 within interior chamber 4 at a desired
temperature, as described further below. Door 5 is hingedly
attached to container 3 by hinges 9 to swing between open (FIG. 1)
and closed (FIGS. 2, 4) positions. An annular sealing gasket 11
provides a seal between door 5 and container 3 when door 5 is
closed, such that main body 3 and door 5 together form a six-sided
or six-walled container or enclosure. Items 40 are removable from
and insertable into (Arrows A in FIGS. 2, 5 7-11 and 13) interior
chamber 4 through entrance opening 6 when door 5 is open.
[0030] Door 5 includes a transparent window 12 which may be double
paned (FIG. 2) with two parallel panes 16 (typically made of glass)
with an annular elastomeric seal 18 therebetween and in contact
therewith to separate panes 16 by a space 20. Space 20 is defined
by the inner perimeter of seal 18 and panes 16 and is filled with
gas or under vacuum to help thermally insulate interior chamber 4
when door 5 is closed to cover entrance opening 6. Door 5 includes
a rectangular annular wall 10 which surrounds window 12 along its
outer edges and is hollow and typically includes a metal skin which
defines a rectangular annular insulated fully enclosed door
interior chamber or compartment 13 with thermal insulation 14
therein which nearly or completely fills compartment 13.
[0031] Control assembly 7 includes an enclosure or housing 8 on
which is mounted a manual control interface 15 and which houses a
temperature control unit 17, a humidity control unit 19 and a
carbon dioxide control unit 21. Interface 15 is in electrical
communication with control units 17, 19 and 21, and also with a fan
assembly 23 within or in communication with interior chamber 4 and
an electric power source 25 outside housing 8. Temperature control
unit 17 is in electrical communication with a temperature sensor 27
within or bounding interior chamber 4 and with an electric heating
unit or device in the form of a heating coil 29 within interior
chamber 4. Temperature control unit 17 is also in electrical
communication with a cooling device or refrigeration assembly 28
which includes internal heat-exchanging pipes 30 and external
components 32 which typically include external heat-exchanging
pipes, a compressor, and an expansion valve such that the
refrigeration assembly provides a typical refrigeration cycle
whereby the refrigerant within the coils is capable of providing
active cooling within interior chamber 4 via the internal coils 30
therein. Cooling and heating devices 28 and 29 serve as
electrically powered temperature-altering devices for altering the
temperature of interior chamber 4, items 40 and other components
within chamber 4 and portions of the walls defining chamber 4.
Humidity control unit 19 is in electrical communication with a
humidity sensor 31 within or bounding interior chamber 4 and with
an actuator such as a solenoid of a water control valve 33 which is
in fluid communication with a water source 35. Thus, humidity
control unit 19 is operatively connected to interior chamber 4 to
control the amount of humidity within chamber 4. Carbon dioxide
control unit 21 is in electrical communication with a carbon
dioxide sensor 37 and an actuator such as a solenoid of a carbon
dioxide control valve 39 which is in fluid communication with a
carbon dioxide source 41. Thus, carbon dioxide control unit 21 is
operatively connected to interior chamber 4 to control the level of
carbon dioxide within chamber 4.
[0032] Main body or container 3 is now described in greater detail.
Container 3 has several generally rigid walls or sidewalls
including a flat vertical rectangular back wall 42, flat
rectangular horizontal top and bottom walls 44 and 46 secured
respectively to the top and bottom of back wall 42 and extending
forward therefrom, and flat vertical left and right side walls 48
and 50 secured respectively to the left and right sides of back
wall 42 and extending forward therefrom. Left and right side walls
48 and 50 are also secured to and extend between the respective
left and right ends of top and bottom walls 44 and 46. Walls 42-50
thus form a box or cup-shaped configuration defining interior
chamber 4 such that walls 44-50 at their front ends define entrance
opening 6. A fully enclosed sealed rectangular cup-shaped interior
cavity or chamber 52 is formed within container 3 separate from
interior chamber 4 and more particularly is defined by a
substantially rigid skin 54 which is typically formed of metal
although it may be formed of a plastic or other suitable material.
Chamber 52 surrounds interior chamber 4 on five five sides thereof.
Wall or sidewall chamber 52 is sealed from external atmosphere and
is nearly or completely filled by insulation 56 and a phase change
material 58 (PCM), each of which is also in a substantially
rectangular cup-shaped configuration corresponding to that of
chamber 52. The phase change material 58 is disposed between the
insulation and interior chamber 4 along the entire inner surface of
insulation 56 and thus essentially completely surrounds interior
chamber 4 on all five sides of container 3. Thus, each of walls
42-50 includes several layers or materials. Insulation 56 may be
formed of a variety of insulation materials which remain in a solid
state throughout the operation of the chamber and which are
generally rigid or compressible. For example, insulation 56 may be
fiberglass, styrofoam, or various types of foam boards or sheets,
such as those formed from polystyrene, polyurethane,
polyisocyanurate and the like. Some of these insulation boards are
referred to commonly as polyiso boards. PCM 58 is discussed in
greater detail further below. Although PCM 58 is shown on all five
sides of container 3 entirely surrounding interior chamber 4,
chamber 1 may also be formed with PCM 58 on only one, two, three or
four sides of container 3 so that PCM 58 is adjacent chamber 4, but
does not surround chamber 4.
[0033] Skin 54 includes a rectangular cup-shaped outer layer 60, a
rectangular cup-shaped inner layer 62 and a rectangular annular
front layer 64 which is substantially vertical and extends between
the front of outer and inner layers 60 and 62. Outer layer 60 thus
forms outer layers of each of the walls of container 3, namely
vertical rear outer layer 66A of back wall 42, horizontal top outer
layer 66B of top wall 44, horizontal bottom outer layer 66C of
bottom wall 46, vertical left outer layer 66D of left side wall 48
and vertical right outer layer 66E of right side wall 50. Inner
layer 62 similarly forms the inner layers of each of these walls,
namely vertical front inner layer 68A of back wall 42, horizontal
bottom inner layer 68B of top wall 44, horizontal top inner layer
68C of bottom wall 46, vertical right inner layer 68D of left side
wall 48 and vertical left inner layer 68E of right side wall 50.
Each of layers 66 and 68 is flat and rectangular.
[0034] Insulation 56 likewise makes up insulation layers of each of
the five walls of container 3 which abut the respective outer layer
66 thereof and extend inwardly therefrom part of the way toward the
respective inner layer 68 thereof. More particularly, insulation 56
includes a vertical flat rectangular insulation layer 70A of back
wall 42 which abuts the front inner surface of outer layer 66A and
extends forward therefrom, a flat rectangular horizontal insulation
layer 70B of top wall 44 which abuts the lower inner surface of
outer layer 66D and extends downwardly therefrom, a flat
rectangular horizontal insulation layer 70C of bottom wall 46 which
abuts the top inner surface of outer layer 66C and extends upwardly
therefrom, a flat rectangular vertical insulation layer 70D of left
side wall 48 which abuts the inner surface of outer layer 66D and
extends inwardly to the right therefrom, and a flat rectangular
vertical insulation layer 70E of right side wall 50 which abuts the
left inner surface of outer layer 66E and extends inwardly to the
left therefrom.
[0035] PCM 58 also forms respective PCM layers of each of the walls
of container 3, namely a vertical flat rectangular PCM layer 72A of
back wall 42 which extends between and is in contact with the front
inner surface of insulation layer 70A and the rear surface of skin
inner layer 68A, a flat rectangular horizontal PCM layer 72B which
extends between and is in contact with the bottom inner surface of
insulation layer 70B and the top surface of inner layer 68B, a flat
rectangular horizontal PCM layer 72C which extends between and is
in contact with the upper surface of insulation layer 70C and the
lower surface of inner layer 68C, a vertical flat rectangular PCM
layer 72D which extends between and is in contact with the inner
surface of insulation layer 70D and the left surface of inner layer
68D, and a flat rectangular vertical PCM layer 72E which extends
between and is in contact with the left inner surface of insulation
layer 70E and the right surface of inner layer 68E. Each PCM layer
17 is thus disposed within a cavity or portion of interior chamber
52 between the corresponding inner layer of the skin and layer of
insulation 70.
[0036] Chamber 1A (FIG. 5) is similar to chamber 1 except that it
includes a door 5A which is somewhat different than door 5 although
both doors are substantially rigid and serve as a wall or sidewall
of the chamber 1 or 1A. Unlike door 5, door 5A does not include a
transparent window which allows someone to view the contents of
interior chamber 4 from outside the chamber without opening the
door. Instead, door 5A is opaque and has a configuration similar to
one of the walls of container 3 and is thus made of several layers.
In particular, door 5A includes a substantially rigid skin 74 which
is relatively thin and typically formed of metal and defines a
fully enclosed vertical rectangular interior cavity or chamber 76
which is separate from chambers 4 and 52, which is sealed from
external atmosphere and in which are disposed an insulation layer
70F and a PCM layer 72F. Skin 74 includes outer end inner vertical
rectangular layers 78 and 80 and a rectangular annular perimeter
layer 82 which extends between and is secured to the respective
outer perimeters of outer and inner layers 78 and 80 such that
layers 78-82 define therewithin chamber 76. Insulation layer 70F
extends from the top to the bottom and from the left side to the
right side of interior chamber 76. Insulation layer 70F also abuts
the inner surface of outer layer 78 and extends inwardly and
rearwardly therefrom and may contact the front inner surface of
inner layer 80 along its outer perimeter although insulation layer
70F only extends part of the way towards inner layer 80 along a
rectangular portion of door 5A which is directly in front of
entrance opening 6. PCM layer 72F is a flat vertical rectangular
layer which extends between and abuts the front surface of inner
layer 80 and the rear surface of insulation layer 70F such that
when door 5A is closed, PCM layer 72F entirely covers or spans the
entrance opening 6 of interior chamber 4. PCM layer 72F is thus
disposed within a cavity or portion of the sidewall or door
interior chamber 76 defined between inner layer 80 and insulation
layer 70F. PCM layer 72F is intended to be permanently disposed
within chamber 76 and is thus not removable therefrom, just as the
PCM layers 72A-E are not removable from interior chamber 52 of
container 3.
[0037] FIG. 6 illustrates a removable PCM packet 84 which is
typically easily carried by one person and otherwise manipulated
with one or two hands for use with chambers configured to receive
packet 84. Packet 84 includes first and second substantially flat
rectangular walls 86 and 88 which together form an outer skin and
overlay one another such that their outer perimeters are
superimposed and in contact with one another while the vast
majority of walls 86 and 88 are spaced from one another to define
therebetween a flat rectangular interior cavity or chamber 89 which
receives therein a flat rectangular PCM layer 72G which nearly or
completely fills chamber 89. Walls 86 and 88 are preferably formed
of a substantially rigid thermally conductive material, such as a
metal. Aluminum, stainless steel and copper are well suited for
this purpose. However, walls 86 and 88 may be formed of a plastic
or other suitable material. Packet 84 has first and second opposed
straight parallel end edges 90 and 92, and first and second
straight parallel opposed side edges 94 and 96 which extend
respectively between end edges 90 and 92 so that edges 90-96 form a
rectangular configuration along the outer perimeters of walls 86
and 88. Walls 86 and 88 are sealed to one another along each of
edges 90-96 so that interior chamber 89 is fully enclosed and
sealed from external atmosphere.
[0038] Chamber 1B is shown in FIG. 7 and utilizes removable PCM
packets 84. Chamber 1B is similar to chambers 1 and 1A and is shown
with door 5 although a door such as door 5A may also be used.
Chamber 1B includes a container 3A which is similar to container 3
except that the insulation entirely or nearly entirely fills the
interior chamber 52 since the PCM material is provided in packets
84 instead of within interior chamber 52. Thus, for example, the
insulation layer 70A in the back wall of container 3A extends all
the way from the front surface of outer layer 66A to the back
surface of inner layer 68A. Similarly, insulation layer 70B extends
continuously from the bottom surface of outer layer 66B to the top
surface inner layer 68B, and insulation layer 70C extends all the
way from the bottom surface of inner layer 68C to the top surface
of outer layer 66C. The insulation layers in the two side walls of
container 3A also extend all the way between the respective inner
and outer layers thereof.
[0039] As shown in FIG. 7, the heating element 29 of chamber 1B is
mounted on the top wall of container 3 within interior chamber 4
adjacent the top thereof. FIG. 7 further illustrates three of the
removable PCM packets 84 within interior chamber 4. One of packets
84 is seated on top inner layer 68C of the bottom wall of container
3, which thus serves as a supporting structure or permanent shelf
for the lower packet 84. Chamber 1B further includes a pair of
horizontal trays 98 which respectively hang downwardly from the
wire or other type shelves 2 such that each tray and the respective
shelf are adjacent one another and define therebetween a respective
rectangular flat horizontal packet-receiving space 100 for
removably inserting therein a respective packet 84 through a front
entrance opening of a respective space 100. Thus, the lowermost
packet 84 is directly below the other two packets as well as
directly below the two shelves and trays, and spaced downwardly
from the lower tray. The middle packet 84 is thus seated atop the
lower tray 98 below and adjacent the lower removable shelf 2.
Similarly, the top or upper packet 84 is seated atop the upper tray
98 below and adjacent the removable upper shelf 2. In addition, the
upper tray 98 is spaced upwardly from the lower shelf 2 so that a
portion of interior chamber 4 is defined between the top of the
lower shelf 2 and the bottom of tray 98 inasmuch as the upper tray
98 and the corresponding upper packet 84 is spaced upwardly from
the lower shelf 2. This portion of interior chamber 4 receives
petri dishes or other items 40 which are seated on the lower shelf
2 so that the temperature of item 40 and the environment
environment in interior chamber 4 surrounding item 40 may be
controlled. Items 40 are thus adjacent, above and out of contact
with the respective packet 84 during the process of temperature and
other environmental control in interior chamber 4. Similarly,
interior chamber 4 includes an upper portion above the upper shelf
2 also configured to receive items 40, which are likewise adjacent,
above and out of contact with the upper packet 84 during the
process of thermal and other environmental control within interior
chamber 4. As previously noted, each packet 84 may be inserted and
removed from its respective space 100 or from atop the bottom wall
(Arrows B in FIGS. 7, 8) through the entrance opening 6 when door 5
is open. Trays 98 serve as PCM packet shelves. However, PCM packets
84 may also be seated on shelves 2 or another support so that items
40 may be seated directly on packets 84.
[0040] Chamber 1C (FIG. 8) is similar to the previous chambers and
includes a container 3B which is similar to but somewhat modified
from the earlier containers. The insulation within interior chamber
52 of container 3B is the same as that described with reference to
the insulation within container 3A of chamber 1B. As shown in FIG.
8, the heating element 29 is mounted adjacent and above the bottom
wall of the container within interior chamber 4 in the same manner
as with chamber 1. Chamber 1C illustrates the use of two PCM
packets 84 in a different orientation than that shown with chamber
1B. A tray 98 is mounted on the top wall of container 3B within the
upper portion of interior chamber 4 so that the upper PCM packet
may slide horizontally (Arrow B in FIG. 8) to be inserted or
removed from the space 100 above tray 98 and below and adjacent the
top wall of container 3B. The 3B. The other packet 84 is positioned
in a vertical orientation behind removable shelves 2 abutting or
adjacent the front inner surface of inner layer 68A of the back
wall of container 3B. More particularly, a clip 102 is secured to
the back wall adjacent the top wall of the container and clips or
clamps the first end edge 90, which serves as the top of packet 84
in the vertical orientation in order to suspend packet 84 in this
rearward position. As will be appreciated, any suitable mechanism
may be used in order to secure packet 84 in its hanging position or
a vertical position closely adjacent the back insulating wall. PCM
packets 84 of insulated chamber 1B and 1C are positioned so that
they do not hinder the insertion and removal of items 40 from
interior chamber 4, that is, items 40 may be inserted and removed
without moving PCM packets from their respective positions within
chamber 4. In addition, packets 84 are configured so that PCM 72G
(like the non-removable PCM 56 of chamber 1) is not visible to the
end user of the insulated chambers 1B and 1C. Moreover, PCM packets
84 are configured and positioned in chamber 4 so that the space
normally reserved for items 40 on shelves 2 (i.e., without the use
of packets 84 or trays 98) is not substantially reduced, and in
most cases the reduction in available space for items 40 is not
significant enough to have any real impact. Thus, the items 40
normally placed in a chamber 4 of a given size may still be placed
therein with the addition of trays 98 and/or packet(s) 84. Although
not shown, it is contemplated that a packet 84 may be positioned in
a space behind or adjacent a "false" wall within chamber 4 such
that the packet is hidden and whereby heat transfer to and from the
packet is largely by convection. For example, such a false wall may
be situated in front of the vertical packet 84 shown in FIG. 8.
[0041] Chamber 1D (FIG. 9) is similar to the previous chambers and
includes a modified container 3C such that the interior chamber 52
contains insulation, PCM, and a heating element 29A sandwiched
therebetween. The insulation layer 70C of chamber 1D is
substantially the same as that described with regard to the
chambers 1B and 1C in FIGS. 7 and 8. Similarly, the insulation in
the left and right side walls of container 3C completely or nearly
fills the portions of chamber 52 within the respective left and
right side walls of container 3C. The insulation layers 70A and 70B
of container 3C are substantially the same as those of chamber 1,
as illustrated in FIGS. 2 and 3. In addition, the PCM layers 72A
and 72B within container 3C are substantially the same as that
shown and described with reference to FIGS. 2 and 3 of chamber 1.
In chamber 1D, only these two PCM layers 72A and 72B are used such
that the bottom wall and left and right side walls of container 1D
do not include such PCM layers. As FIG. 9 illustrates, interior
chamber 4 is free of a heating element such as heating element 29
of the previous embodiments. Instead, heating element 29A is
sandwiched between insulation layer 70A and PCM layer 72A and is
thus substantially vertically oriented and in contact with each of
said layers. Element 29A is thus entirely external to interior
chamber 4.
[0042] Chamber 1E (FIG. 10) is similar to chamber 1D except that it
includes a heating element 29A which is sandwiched between PCM
layer 72A and inner layer 68A. Element 29A is thus in contact with
the rear surface of layer 68A and the front surface of PCM layer
72A.
[0043] Chamber 1F (FIG. 11) is similar to chamber 1A (FIG. 5)
except that the various layers 72 of PCM 58 are replaced by
numerous encapsulated PCM pellets 104 and a liquid medium 105 in
which the pellets 104 are disposed. As shown in FIG. 12, each
pellet 104 includes a solid capsule 106 having an inner surface
which defines an interior chamber 108 or an enclosure which is
sealed from the external atmosphere or environment by the solid
skin or capsule 106. Interior chamber 108 is nearly or completely
filled with PCM 58. As shown in FIG. 11, the mixture of pellets 104
and medium 105 form layers 110 which include a substantial amount
of PCM 58 and are analogous to layers 72. While layers 110 may be
on all sides of interior chamber 4, FIG. 11 shows only layers 110A,
110B, 110C and 110F, which are respectively analogous to layers
72A, 72B, 72C and 72F. Typically, pellets 104 are packed in as
tightly or nearly as tightly as they can within the portion of
interior chamber 52 defined between insulation 56 and inner layer
62 of skin 54. Pellets 104 are similarly packed into the portion of
interior chamber 76 of the door between the insulation layer 70F
and inner layer 80 of skin 74. Pellets 104 define therebetween
interstitial spaces which are typically completely or nearly filled
by liquid medium 105. Although in the exemplary embodiment, medium
105 is in a liquid form, it may also be in a gaseous form. In any
case, the interior chamber 52 is completely or nearly filled by
insulation 56, pellets 104 and medium 105. Similarly, the interior
chamber 76 of the door is nearly or completely filled with
insulation 70F, pellets 104 and medium 105.
[0044] As shown in dashed lines in FIG. 11, chamber 1F may include
an inlet 112 and an outlet 114 communicating with the portion of
interior chamber defined between insulation 56 and inner layer 62
of skin 54 such that a liquid or a mixture of pellets 104 and
liquid medium 105 may be pumped or otherwise moved into this
portion of the interior cavity via inlet 112 (arrow C) and out of
this portion of the interior cavity through outlet 114 (arrow D).
The provision of an inlet and an outlet is one manner of filling
this portion of the interior chamber 52 with pellets 104 and medium
105, and also would allow for the pellets and medium to be removed
via outlet 114 and, if desired, replaced with another set of
pellets and liquid medium in which the PCM 58 of the pellets has a
different melting or freezing temperature than that of the original
pellets. It is noted that liquid 105 may be a phase change material
which serves in the same fashion as PCM 58, or it may remain in a
liquid state within the operational parameters of chamber 1F. The
illustration with the use of inlet 112 and outlet 114 may represent
the type of insulated chamber which uses a water jacket. Thus,
instead of using the water jacketed insulated chamber in the
standard manner, pellets 104 and liquid medium 105 may instead be
used to fill the interior chamber of the water jacket in order to
utilize the advantage of PCM 58 of the present invention.
[0045] Chamber 1G (FIG. 13) is similar to chamber 1F in that it
also utilizes PCM pellets 104. However, instead of pellets 104
being disposed within liquid medium 105, pellets 104 of chamber 10
are embedded in a solid matrix 116. More particularly, the matrix
116 and embedded pellets 104 form respective flat rectangular
layers 118 which are analogous to PCM layers 72A-F and layers 110
such that each of the layers is flat and rectangular and either
horizontal or vertical as previously discussed with respect to
layers 72. FIG. 13 shows specifically layers 118A-C, 118E and 118F.
However, unlike layers 72 and layers 110, layers 118 are in the
exemplary embodiment not within the interior chamber 52 defined by
skin 54 of such chambers as chamber 1, 1A and 1F. Although layers
118 could be positioned within chamber 52 in the analogous
positions of layers 72 and 110, the use of layers 118 illustrates
one manner of forming layers comprising PCM 58 wherein the layers
are external to interior chambers 52 and 76. Thus, chamber 1G may
include a container 3D and a door 5C each of which has a somewhat
different configuration than those of the previous embodiments.
Container 3D retains skin 54 and its various layers to define there
within the interior chamber 52. However, insulation 56 itself
either completely or nearly fills interior chamber 52. FIG. 13
shows that inner layers 68 of skin 54 are positioned closer to the
corresponding outer layers 68 such that outer layers 66 abut the
outer surface of insulation 56 and the inner layer 68 abut the
inner surface of insulation 56. Thus, insulation 56 in FIG. 13
appears to have the same thickness as insulation 56 in FIG. 11.
However, the inner and outer layers 66 and 68 may also be spaced
apart from one another as in the previous embodiments such that
insulation 56 still fills the entire chamber 52 and is thicker, as
shown in FIG. 7. Each of layers 118 has an outer surface 120 and an
inner surface 122.
[0046] Each outer surface 120 of a given layer 118 which is part of
container 3D abuts an inner surface of a corresponding inner layer
68 so that each layer 118 extends inwardly therefrom to inner
surface 122. Thus, for instance, outer surface 120 of layer 118A is
vertical and abuts the vertical inner surface of back inner layer
68A and extends inwardly therefrom to vertical surface 122 of layer
118A. The outer surface 120 of layer 118B serves as a top surface
which thus abuts the inner or bottom surface of top inner layer 68B
so that layer 118B extends downwardly therefrom to the horizontal
inner or bottom surface 122 thereof. The outer surface 120 of layer
118C thus serves as a bottom horizontal surface from which layer
118C extends upwardly to the inner or top horizontal surface 122
thereof. The left and right walls of container 3D are formed in a
similar manner to the back wall thereof such that the corresponding
layer 118 is vertical, and the inner and outer surfaces 120 and 122
of the corresponding vertical layers 118 (layer 118E shown in FIG.
13) are vertical and oriented such that the outer layer 120 abuts
the corresponding inner layer 68 and extends inwardly therefrom to
the vertical inner surface 122. Thus, the inner surfaces 122 of the
layers 118 define interior chamber 4, unlike the earlier
embodiments in which the inner layers 68 of skin 54 defined
interior chamber 4.
[0047] Although door 5C is similar to the doors of the earlier
embodiments, it also differs somewhat in that inner layer 80
defines a vertical flat rectangular recess 124 in which layer 118F
is received with its vertical outer or front surface 120 abutting
the vertical inner surface of layer 80 and extending forward
therefrom to the flat vertical inner or rear surface 122, which
bounds interior chamber 4 when door 5C is closed. Although layer
118F is shown disposed in recess 124, a layer similar to 118F may
be mounted on a door without such a recess and thus project forward
beyond the forward most portion of the inner skin.
[0048] In the exemplary embodiment, solid matrix 116 is typically
formed of a cured resin. Thus, during formation of layers 118, the
original material which ultimately becomes matrix 116 is a liquid
resin or in liquid form and thus cures to form the solid resin. In
one embodiment, pellets 104 are mixed into a paint, which can then
be painted onto any given surface, such as the inner layer 62 and
the inner layer 80 and then allowed to dry. Paints typically
contain a resin and a solvent, such that when the solvent dries,
the resin is allowed to cure by chemical reaction. Some paints are
also thermosetting, meaning that they are also heated in order to
cure the resin. In another embodiment of solid matrix 116, the
resin may not include a solvent which needs to dry in order to
cure. For example, some resins are simply heat cured from a liquid
state to a solid state without or with extremely minimal
evaporation of components making up the liquid resin. Other liquid
resins may be light cured in order to reach the solid state.
[0049] Thus, the layers 118 may be formed in several different
ways. Where the matrix and its liquid form is a paint, the paint
with pellets 104 mixed into it may simply be painted onto a given
desired surface and allowed to dry. Another option is to pour a
given liquid resin with the pellets 104 mixed therein into a cavity
or recess such as recess 124 (such as when door 5C is laid
horizontal with the recess 124 facing upwardly), and either allowed
to dry, as with the paint, or cured by heat, light or any other
suitable method in order to cure the resin within the recess.
Alternately, any of the layers 118 may be independently formed in a
mold cavity and subsequently mounted in the positions shown in FIG.
13 by any suitable mechanism. For instance, the bottom layer 118C
may simply be laid atop the inner inner layer 68C, or may be
adhered with a glue or another adhesive thereto. The other layers
118 may similarly be adhered by a glue or an adhesive or so forth.
Further, the various layers 118 of container 3D may be formed as a
single cup-shaped piece. Such formations may be done in a separate
mold, or may use the inner layer 62 of skin 54 to define a portion
of the mold. Matrix 116 may have varying degrees of thermal
conductivity. The thermal conductivity may be enhanced by
incorporating metal chips or other materials which are highly
thermally conductive into the liquid resin during formation of the
layers 118.
[0050] FIG. 14 shows another PCM packet or shelf 84A which is
similar to packet 84 shown in FIG. 6. Shelf 84A thus includes
generally flat rectangular bottom wall 88 and a generally flat
rectangular top wall 86A which define therebetween an interior
chamber 89A which is filled with a layer 72H of PCM. PCM layer 72H
typically completely or nearly fills interior chamber 89A. It is
noted that PCM layer 72H of packet 84A or PCM layer 72G of packet
84 (FIG. 6) may be replaced with pellets 104, along with a gas or
liquid medium 105 (FIG. 11) or embedded in solid matrix 116 (FIG.
13). Walls 86A and 88 are formed of the same materials as
previously described with regard to packet 84, and are joined to
one another to form end edges 90 and 92, and side edges 94 and 96.
Unlike wall 86 of packet 84, which is substantially flat in a
continuous manner from adjacent edge 90 to adjacent edge 92 and
from adjacent edge 94 to adjacent edge 96, wall 86A includes an
upper flat portion 126 which extends from adjacent edge 90 to
adjacent edge 92 and from adjacent edge 94 to adjacent edge 96, but
is interrupted by a plurality of recesses 128 extending downwardly
therefrom. In the exemplary embodiment, packet 84A includes six
recesses 128 although the number may vary depending on the size of
the packet and the specific need. Although recesses 128 may be of
any desired shape, each recess 128 is shown with a circular central
portion 130 and a pair of opposed finger receiving portions 132
which extend laterally outwardly from central portion 130 on
opposite sides thereof and away from one another. The bottom of
each recess 128 is defined by a flat horizontal recessed wall 134
which is spaced downwardly from upper flat portion 126. An annular
side wall 136 at its lower end is rigidly secured to and extends
upwardly from the outer perimeter of recessed wall 134 to a rigid
connection at its upper end to upper flat portion 126, whereby each
recessed wall 134 and the corresponding side wall 136 defines the
corresponding recess 128. Each recess 128 has a top entrance
opening 138 through which a given storage item 40 may be downwardly
inserted and upwardly removed, as indicated at arrow E in FIG.
14.
[0051] With continued reference to FIG. 14, the specific storage
item 40 includes a container or petri dish 140 having a flat
circular bottom wall 142 and a circular annular side wall 144
rigidly secured to and extending upwardly from the bottom wall 142
to define there within a cylindrical cavity 146 with a top entrance
opening 148. Cavity 146 is thus configured to receive various
contents via entrance opening 148 and/or have the contents removed
thereby. In the exemplary embodiment, item 40 includes the
contents, which are in the form of a culturing medium 150 with
living cells 152 to be grown or cultured thereon.
[0052] The sectional view of FIG. 14A illustrates the relative
positions of the petri dish 140 and its contents to the
corresponding recess 128 and various components of the packet 84A,
including the PCM. The PCM of layer 72H includes a lateral portion
or portions 149 which may also be referred to as a
recess-surrounding portion. The PCM of layer 72H also includes
respective sub-recess portions 151 which are located directly below
the corresponding recess 128 and recessed wall 134. The lateral
portions 149 extend laterally outwardly from annular side wall 136
in all directions so that this portion of the PCM, as viewed from
above, surrounds the corresponding annular side wall 136, as well
as the bottom wall 134, recess 128, and when petri dish 140 is
disposed within 128, also the bottom wall 142 thereof, at least a
portion of side wall 144, and all or part of medium 150 and cells
152. Portions 149 have a top surface which abuts the bottom surface
of upper flat portion 126 whereby the PCM of layer 72H extends from
below recessed wall 134 and the bottom of petri dish 140 to above
recessed wall 134, bottom wall 142, most or all of side wall 144
and all or part of medium 150 and cells 152. In the exemplary
embodiment, bottom wall 142 of dish 140 is seated on horizontal
flat recessed wall 134 with annular side wall 144 abutting or
closely adjacent annular side wall 136, which typically has a
substantially similar shape as side wall 144 as viewed from above
so that the petri dish side wall and the contents of the dish are
adjacent portions 149 of PCM. In the exemplary embodiment, the top
of the petri dish is no higher than the top of the top of upper
flat portion 126 although this may vary. Likewise, the medium 150
and cells 152 are typically no higher than the top of portion
126.
[0053] Referring now to FIG. 15, chamber 1H is configured to use
the packets or shelves 84A shown in FIG. 14. Chamber 1H is similar
to chamber 1B shown in FIG. 7 except that chamber 1H shows a
different shelving configuration. FIG. 15 illustrates that the
lower packet or shelf 84A is removably positioned atop inner layer
68C of the bottom wall, similar to the lower packet 84 in FIG. 7.
However, the middle packet or shelf 84A is seated atop a wire or
other shelf 2 rather than on a tray 98 as in FIG. 7. The bottom
walls 88 of each of the lower and middle shelves or packets 84A are
atop a supporting surface or shelf whereby each packet 84A serves
as a shelf on which the various items 40 are seated within interior
chamber 4. The upper shelf 84A of chamber 1H is supported within
interior chamber 4 in a different manner. More particularly,
support ledges 154 are connected to and extend inwardly from the
left and right walls defining interior chamber 4 in order to
support the upper packet 84A respectively along its left and right
side edges 94 and 96. FIG. 15 shows only one of support ledges 154,
which extends from adjacent the back of interior chamber 4 to
adjacent the front of interior chamber 4. Thus, packet 84A along
the left and right edges 94 and 96 form respective lips which are
seated on the support ledges 154. These lips or side edges of
packet 84 easily slide along support ledges 154 to insert the
packet or shelf 84A into chamber 4 or remove it therefrom via
entrance opening 6 when door 5 is opened.
[0054] Although each of the chambers described above vary somewhat
from one another, all of them operate in essentially the same basic
manner. Various processes of the present invention are illustrated
in the flow chart of FIG. 17 at blocks 160-168 and will be referred
to hereafter although not necessarily in the same order. Each
insulated chamber is configured to control various atmospheric
conditions within interior chamber 4 (block 162). For example,
power source 25 provides the power for running the various
electrical components of chamber 1, such as fan assembly 23,
control units 17, 19, and 21, refrigeration assembly 28, heating
unit 29 and the solenoid or other actuator of control valves 33 and
39. The user of chamber 1 manipulates the settings of temperature,
humidity and CO.sub.2 level within interior chamber 4 via control
interface 15, which may include three or more buttons or controls
as shown in FIG. 1 which correspond respectively to these three
features. Sensors 27, 31 and 37 respectively sense or determine the
temperature, humidity and CO.sub.2 level within interior chamber 4
and produce respective signals which are sent respectively to
temperature control unit 17, humidity control unit 19 and CO.sub.2
control unit 21. Based on the signal from temperature sensor 27,
temperature control unit 17 controls heating unit 29 to turn it
off, turn it on and/or control the degree of heat produced thereby
for providing heat within interior chamber 4 as well as heat to PCM
material 58 radiated through the various inner layers 68 of skin
54. Temperature control unit 17 may also control refrigeration
assembly 28 in response to the signal from temperature sensor 27 to
control the degree of cooling provided thereby within interior
chamber 4, such as by turning it off or turning it on. Based on the
signal from humidity sensor 31, humidity control unit 19 controls
the solenoid or other actuating mechanism for operating control
valve 33 to increase or decrease the amount of moisture within
interior chamber 4. Similarly, based on the signal from CO.sub.2
sensor 37, CO.sub.2 control unit 21 controls the solenoid or other
actuating mechanism of control valve 39 in order to increase or
decrease the amount of carbon dioxide entering interior chamber 4
in order to provide the appropriate level of CO.sub.2 in accordance
with the input settings. Fan assembly 23 may be operated to rotate
the fan in order to gently blow the gas within interior chamber 4
to maintain a substantially uniform temperature, humidity and level
of carbon dioxide throughout the chamber. Fan assembly 23 may be
operated on a continuous basis or intermittently in a variety of
predetermined patterns, which may be related to the opening and
closing of door 5, especially to help recover the internal
temperature and the CO.sub.2 and humidity levels after the door has
been opened and closed.
[0055] PCM 58 of the present invention helps to maintain interior
chamber 4 at a substantially constant temperature due to the
significant amount of latent heat which PCM 58 absorbs or releases
during its phase change, namely melting or freezing. PCM 58 is
especially helpful in maintaining that temperature if there is a
loss of power to the heating element 29 or refrigeration assembly
28 for an extended period. More particularly, PCM 58 is configured
to have a melting or freezing phase change temperature which is at
or about a desired selected temperature of interior chamber 4.
Thus, the storage item or items 40 may be placed in interior
chamber 4 to help maintain the storage items near the phase change
temperature of a given PCM 58 (block 161). Typically, the melting
or freezing temperature of PCM 58 is within the range of about
-40.degree. C. (-40.degree. F.) to about 150.degree. C.
(302.degree. F.) or 160.degree. C. (320.degree. F.). However, the
melting or freezing temperature of PCM 58 may be less or greater
than this range.
[0056] In one embodiment, the melting temperature of PCM 58 is
about 37.degree. C. (98.6.degree. F.) since this is one of the most
commonly used temperatures for culturing bacteria and mammalian
cells. One suitable phase change material which has a melting or
freezing temperature of about 37.degree. C. is available under the
name "BioPCM Phase Change Material-37" from Phase Change Energy
Solutions, Inc. of Asheboro, N.C. This product includes a phase
change component and a fire suppression component. The phase change
component is a derivative of fatty acids. The above noted business
also produces PCMs which have respective melting or freezing
temperatures anywhere within the range of about -40.degree. C. to
about 150.degree. C. or 160.degree. C. Similarly, phase change
materials which are suitable for use as PCM 58 in the present
invention are available from Entropy Solutions, Inc. of
Minneapolis, Minn. Entropy Solutions, Inc. also produces a large
variety of PCMs which have a respective melting temperature within
the range of about -40.degree. C. to about 150.degree. C. or so.
For example, one such PCM which melts or freezes at about
37.degree. C. is available from Entropy Solutions, Inc. under the
name "PureTemp 37." Likewise, Entropy Solutions, Inc. produces
other PCMs, such as "PureTemp -40" having a melting point of about
-40.degree. C., "PureTemp -12" having a melting point of about
-12.degree. C., "PureTemp 4" having a melting point of about
4.degree. C., "PureTemp 23" having a melting point of about
23.degree. C., "PureTemp 30" having a melting temperature of about
30.degree. C., "PureTemp 40" having a melting point of about
40.degree. C. and "PureTemp 50" having a melting point of about
50.degree. C. This company also produces a much wider variety of
PCMs, for example PCMs (with analogous names) which have melting or
freezing points respectively of about -14.degree. C., about
7.degree. C., about 7.degree. C., about 15.degree. C., about
18.degree. C., about 27.degree. C., about 30.degree. C., about
43.degree. C., about 48.degree. C., about 53.degree. C., about
55.degree. C., about 56.degree. C., about 61.degree. C., about
68.degree. C., about 103.degree. C. and about 151.degree. C.
Entropy Solutions, Inc. is capable of producing a PCM of
substantially any desired melting temperature. Entropy Solutions,
Inc. indicates that the PCMs which they produce are from
vegetable-based fats and oils. It is noted, however, that any
suitable phase change material having the desired melting
temperature may be used as PCM 58.
[0057] In some cases, it is desired to maintain the temperature of
interior chamber 4 and item 40 at a temperature higher than room
temperature (about 22 to 23.degree. C. or 71 to 73.degree. F.) or
the ambient temperature, and thus PCM 58 is a solid at room
temperature or at the ambient temperature. To take advantage of the
phase change concept of such an embodiment of material 58, heating
element 29 is operated in order to heat interior chamber 4 and the
phase change material 58 until it melts at its melting phase change
temperature (block 160). Most preferably, all of PCM 58 is melted
so that PCM 58 is able to provide the greatest duration of
substantially constant temperature during its phase change from the
liquid state to the solid state while there may be no additional
heat source available to maintain the interior temperature of
interior chamber 4, such as during a power outage. In the heating
scenario, each of the chambers positions the phase change material
between the solid insulation and interior chamber 4, or positions
the phase change material within interior chamber 4 itself so that
insulation 56 of the container and the insulation of door 5A and/or
the double paned window of door 5 substantially aids in preventing
loss of heat from interior chamber 4.
[0058] In other cases, it is desired to maintain the temperature of
interior chamber 4 and item 40 at a temperature lower than room
temperature or the ambient temperature, and thus PCM 58 is a liquid
at room temperature or at the ambient temperature. Thus,
refrigeration assembly 28 is operated in order to cool interior
chamber 4 and the phase change material 58 to its freezing point or
phase change temperature so that it freezes or solidifies (block
160). Most preferably, all of PCM 58 is frozen or solidified so
that PCM 58 is able to provide the greatest duration of
substantially constant temperature during its phase change from the
solid state to the liquid state while there may be no additional
cooling or refrigeration source available to maintain the interior
temperature of interior chamber 4, such as during a power outage.
In the refrigeration scenario, the phase change material in the
respective insulation chambers is positioned so that insulation 56
of the container and the insulation of door 5A and/or the double
paned window of door 5 substantially aids in preventing the
transfer of external heat into interior chamber 4.
[0059] Although PCM 58 is well suited to help maintain the
temperature during a power outage, it also helps in a variety of
other situations. For instance, PCM 58 helps maintain and/or
expedite recovery of the desired temperature within interior
chamber 4 during and after door 5 is opened (FIG. 1) such as when
item or items 40 are inserted and/or removed from interior chamber
4 (Arrows A in FIGS. 2, 5, 7-11, 13). Further, PCM 58 helps
maintain or expedite recovery of the desired temperature when the
temperature in chamber 4 is otherwise changed (increased or
decreased) due to such factors as electrical power fluctuations,
gas injections such as injection of carbon dioxide via CO.sub.2
control unit 21, liquid injections such as injection of water via
humidity control unit 19, exothermic or endothermic reactions
occurring within item or items 40, and electronic devices which are
part of an item 40. Such an electronic device might be, for
example, lighting equipment such as might be used to simulate
sunlight for growing plants, such that the light would produce heat
when turned on within chamber 4. Another type of such an electronic
device is a water pump for pumping water through an aqua tank, such
as used for growing algae. Other examples of such an electronic
device are a shaker for agitating a solution to facilitate growth,
or a cell roller for rolling a bottle back and forth. Any of these
electronic devices or others would during operation produce heat
which would likewise tend to heat chamber 4 and any item therein.
In addition, turning such electronic devices off while in chamber 4
would reduce the amount of heat energy that the electronic device
produced within chamber 4 and thus alter the temperature in chamber
4. Likewise, altering the operation of such electronic devices in
particular ways may also change the amount of heat that the device
produces within chamber 4 at a given time. PCM 58 thus helps to
maintain and/or facilitate recovery of the desired chamber 4
temperature in all of these scenarios or any other situation which
would affect the internal temperature of chamber 4.
[0060] PCM 58 enhances the ability to maintain the stability of the
temperature within chamber 4 as well as the uniformity of the
temperature throughout chamber 4. The use of PCM 58 also enhances
humidity uniformity in chamber 4 in combination with the humidity
controls of the insulated chambers of the present invention, such
that a stable dew point can be created in chamber 4, and the
formation of condensation on items within chamber 4 or the walls
defining chamber 4 can be minimized or eliminated. While the
usefulness of PCM 58 has been described primarily as being related
to its phase change characteristics, it is worth noting that PCM 58
also acts as an effective thermal mass and/or a thermal
insulator.
[0061] It is also noted that other than PCM 58 and possibly the
liquid medium 105, the other components of the various insulated
chambers of the present invention are not considered to be PCMs,
but rather remain in a single state, typically solid, throughout
the entire range of the operational parameters of the given
insulated chamber. Thus, among the components that remain in a
solid state over the entire operational parameter of the insulated
chambers of the present invention are the skins of the container
and door, the control assembly, the various layers of insulation 70
and the like, the various control units, sensors and control
valves, the heating and cooling devices (other than the liquid
refrigerant within the cooling device), glass panes of the door
where used, the seals used between the panes and between the door
and the container, the wire or other similar shelves, the outer
skin of the PCM packets, the fan assembly, the solid matrix when
used, and any other components which would obviously remain in a
solid state during the normal operational parameters of the
insulated chamber.
[0062] Although the various insulated chambers described herein are
similar, the certain aspects of the configurations may be more
suited to certain purposes. For example, the upper and middle
packets 84 in chamber 1B (FIG. 7) are positioned below and adjacent
the respective shelf 2 and item 40 thereon, which is better suited
for when the desired temperature of chamber 4 and item 40 is above
the ambient temperature. On the other hand, the upper packet 84 in
chamber 1C (FIG. 8) is positioned above and adjacent the upper
shelf 2 and upper item 40 thereon, which is better suited for when
the desired temperature of chamber 4 and item 40 is below the
ambient temperature. Generally, the PCM is distributed
strategically to enhance natural convection, and thus more PCM is
located toward the bottom of chamber 4 when the desired chamber 4
temperature and PCM melting temperature is above the ambient
temperature, whereas more PCM is located toward the top of chamber
4 when the desired chamber 4 temperature and PCM melting
temperature is below the ambient temperature. In addition, more PCM
is typically positioned adjacent the door opening to offset the
heat loss path created in this area. It is further noted that
various of the thermally conductive materials used in the present
invention enhance thermal conduction between the PCM and interior
chamber 4 and between the PCM and components within chamber 4
including item 40. In particular, layers 86 and 88 of packet 84
enhance such thermal conduction, as do inner layer 62 of skin 54
(FIGS. 2, 3) and inner layer 80 of skin 74 of door 5A (FIG. 5).
[0063] FIG. 16 illustrates an additional advantage of using packets
or shelves 84A. More particularly, each shelf 84A is removable from
and insertable into interior chamber 4 with items 40 thereon within
recesses 128, as indicated at arrow F (block 161). Thus, a given
packet 84A may be removed from interior chamber 4 and placed at a
position outside the interior chamber 4 such as on a support
surface 156 while the storage items 40, shown here as petri dishes
140, and the contents thereof, remain seated on the shelf within
recesses 128 (block 163). While the storage items 40 and/or shelves
84A are removed from interior chamber 4, various procedures may be
undertaken with regard to the storage items, either while the
storage items are on or removed from the given shelf 84A or a
similar shelf (block 164). Support surface 156 may, for example, be
in the form of a table, or a counter which is part of a fume hood
whereby fumes from the petri dishes or other items under the hood
may be exhausted. During the culturing of cells 152, it is
necessary for the cells to be fed a suitable food, as indicated at
arrow G. Thus, a worker may feed the cells 152 on medium 150 while
the petri dish is seated within recesses 128 on packet 84A while
the packet is on support surface 156 within a fume hood or the
like. When the petri dishes are placed within recesses such as
recesses 128, or remain seated atop a PCM packet like packet 84 in
FIG. 6, the PCM of the corresponding packet helps to maintain the
desired temperature of the item 40, including the medium 150 and
cells 152 while they are outside the interior chamber 4 of
insulated chamber 1H or the like. In addition, FIG. 16 illustrates
that a given petri dish or other storage item 40 may be removed
from the shelf or packet 84A when both are outside interior chamber
4 in order that the storage item 40 may be manipulated for other
purposes. For example, storage item 40 may be removed from the
packet (arrow H) and seated on another support surface 158. Support
surface 158 also represents, for example, a scale on which item 40
may be weighed, or a microscope so that cells 152 or other
components of item 40 may be viewed under the microscope. After a
given item 40 has been manipulated on surface 158 or by any given
tool as desired, it may be returned to the recess of packet 84
(arrow H) and other items 40 may similarly be removed and
reinserted on packet 84. Once all procedures involving storage
items 40 have been performed outside the insulated chamber, packet
84 with the various items 40 may be reinserted into interior
chamber 4 (block 165).
[0064] Each of the chambers of the present invention may also be
configured with two or more PCMs each of which has a different
melting or freezing point. Thus, for example, one or more of layers
72A-E of chamber 1 (FIGS. 2-4) or layers 72A-F of chamber 1A (FIG.
5) may be formed of one PCM having a first melting or freezing
phase change temperature while one or more of the other of said
layers 72 may be formed of a PCM having a second melting or
freezing phase change temperature which is different than the first
melting or freezing temperature. Similarly, the layer 72G within
one of packets 84 of chambers 1B or 1C (FIG. 7-8) may be formed of
a PCM having the first melting or freezing temperature while
another one of the layers 72G of the corresponding chamber 1B or 1C
is formed of a PCM having the second melting or freezing
temperature. Likewise, the layers 72A of chambers 1D or 1E (FIGS.
9-10) may have the first melting or freezing temperature while the
respective layer 72B has the second melting or freezing
temperature. Moreover, any one of the above noted PCM layers 72 may
be formed of two or more different PCMs each having different
melting temperatures. Whether these two or more PCMs are in
separate layers or intermixed, the chamber thus provides the
corresponding PCM for the respective first, second or third
selected internal temperature of the interior chamber. In addition,
the encapsulated pellets 104 of chambers 1F and 1G (FIGS. 11 and
13) may include two or more batches of pellets 104 such that the
PCM 58 within one batch has a melting or freezing phase change
temperature which is different than that of the other batch or
batches. Configuring the chambers to have PCMs with differing
melting or freezing temperatures may be useful, for example, in the
pharmaceutical industry. In particular, drug manufacturers run
stability tests on various medicines respectively at 30.degree. C.
and 40.degree. C. (104.degree. F.). Thus, the chambers of the
present invention may be configured with one PCM having a melting
point of about 30.degree. C. and another PCM having a melting point
of about 40.degree. C. to facilitate maintaining the temperature of
interior chamber 4 at the corresponding temperature as desired by
the user. The melting or freezing phase change temperatures of the
two PCMs in the above example are both, for example, above
0.degree. C. and above the typical ambient temperature or typical
room temperature of about 22.degree. C. or 23.degree. C. However,
two or more PCMs used with a given insulated chamber of the present
invention may also be configured to have melting or freezing phase
change temperatures which are both below 0.degree. C., the ambient
temperature or the room temperature noted above, or may also be
configured such that the phase change temperature of one of the
PCMs is above one of these reference temperatures and the other is
below the corresponding reference temperature.
[0065] Thus, where the chamber utilizes two phase change materials
each having different melting or freezing phase change
temperatures, the chamber may be operated to either heat or cool
the first phase change material with one of the heating or cooling
devices carried by the chamber to melt or freeze the first phase
change material at its melting or freezing temperature while also
heating or cooling the interior chamber to that temperature and
incubating, storing or maintaining a given item within the interior
chamber at about this first melting or freezing temperature.
Subsequently, the chamber may be similarly operated to heat or cool
the second phase change material and the interior chamber at a
second melting or freezing phase change temperature of the second
phase change material such that it melts or freezes. Then, either
the item that was incubated, stored or maintained at the first
temperature may also be incubated, stored or maintained at the
second temperature (block 166), or it may be removed and another
item may be inserted into interior chamber 4 (block 167) and
incubated, stored or maintained at or near the second temperature
(block 168). It is noted that the processes illustrated in FIG. 17
do not necessarily occur in the order shown nor are the processes
necessarily separate as might be suggested by the arrows.
[0066] In the foregoing description, certain terms have been used
for brevity, clearness, and understanding. No unnecessary
limitations are to be implied therefrom beyond the requirement of
the prior art because such terms are used for descriptive purposes
and are intended to be broadly construed.
[0067] Moreover, the description and illustration of the invention
is an example and the invention is not limited to the exact details
shown or described.
* * * * *