U.S. patent application number 14/722706 was filed with the patent office on 2015-10-01 for temperature controlled cargo containers.
The applicant listed for this patent is AAR Manufacturing, Inc.. Invention is credited to David Scott Farrar, Mark Hugh, Karen Rutter, Mark Rutter.
Application Number | 20150274415 14/722706 |
Document ID | / |
Family ID | 47742154 |
Filed Date | 2015-10-01 |
United States Patent
Application |
20150274415 |
Kind Code |
A1 |
Farrar; David Scott ; et
al. |
October 1, 2015 |
Temperature Controlled Cargo Containers
Abstract
Temperature controlled cargo containers may include thermal
masses conditioned to temperatures above and/or below a target
temperature. Example thermal masses may include plates including
phase change materials, such as eutectic materials. One or more
fans and flapper valves may be selectively operated to circulate
air in the cargo container across one or more of the thermal masses
to maintain the temperature within the cargo container within a
prescribed temperature band. Some example temperature controlled
cargo containers may include refrigeration units and/or heaters for
regenerating the thermal masses when receiving power from an
external power source and/or may include one or more rechargeable
batteries for providing power during transport or storage
independent of external power sources.
Inventors: |
Farrar; David Scott;
(Marietta, OH) ; Rutter; Karen; (Marietta, OH)
; Rutter; Mark; (Lowell, OH) ; Hugh; Mark;
(Marietta, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AAR Manufacturing, Inc. |
Wood Dale |
IL |
US |
|
|
Family ID: |
47742154 |
Appl. No.: |
14/722706 |
Filed: |
May 27, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13662648 |
Oct 29, 2012 |
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14722706 |
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12705803 |
Feb 15, 2010 |
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13662648 |
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61244232 |
Sep 21, 2009 |
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Current U.S.
Class: |
165/248 |
Current CPC
Class: |
B65D 88/745 20130101;
F25D 11/025 20130101; F25B 2400/06 20130101; F25D 2400/02 20130101;
F25D 11/006 20130101; F25D 11/003 20130101 |
International
Class: |
B65D 88/74 20060101
B65D088/74 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2010 |
EP |
10817879.9 |
Sep 17, 2010 |
US |
PCT/US2010/049246 |
Claims
1. A method of controlling the temperature of a product, the method
comprising: placing a product in an interior storage space of a
container, the container comprising an enclosure including
insulated walls, wherein the interior storage space is within the
enclosure, wherein the container includes a warm phase change plate
and a cold phase change plate, and wherein each of the warm phase
change plate and cold phase change plate is disposed within the
enclosure and is arranged for selective heat exchange with the
interior storage space, and wherein at least one flapper valve is
arranged to selectively permit and obstruct airflow about at least
one of said warm phase change plate and said cold phase change
plate; and controlling a temperature of the product by at least one
of raising a temperature of the interior storage space by
recirculating across the warm phase change plate without
substantial air flow across the cold phase change plate, and
lowering the temperature of the interior storage space by
recirculating air across the cold phase change plate without
substantial air flow across the warm phase change plate.
2. The method of claim 1, wherein controlling the temperature of
the interior storage space includes sensing a temperature
associated with the product; wherein lowering the temperature of
the interior storage space comprises, if the temperature associated
with the product is above a target temperature range, operating a
cooling fan associated with causing air flow across the cold phase
change plate to draw air from the interior storage space through a
separator wall at least partially interposing the interior storage
space and the cold phase change plate, opening one of said at least
one flapper valve and flowing the air past the cold phase change
plate, and discharging the air into the interior storage space; and
wherein raising the temperature of the interior storage space
comprises, if the temperature associated with the product is below
the target temperature range, operating a warming fan associated
with causing air flow across the warm phase change plate to draw
air from the interior storage space through a separator wall at
least partially interposing the interior storage space and the warm
phase change plate, opening one of said at least one flapper valve
and flowing the air past the warm phase change plate, and
discharging the air into the interior storage space.
3. The method of claim 1, further comprising, prior controlling the
temperature of the product, conditioning at least one of the warm
phase change plate and the cold phase change plate.
4. The method of claim 3, wherein conditioning the cold phase
change plate includes operating a refrigeration unit comprising at
least one evaporator coil extending through an interior of the cold
phase change plate to cause freezing of a cold phase change
solution within the cold phase change plate; and wherein
conditioning the warm phase change plate includes operating a
heater in thermal contact with the warm phase change plate to melt
a warm phase change solution within the warm phase change
plate.
5. The method of claim 1, wherein controlling the temperature of
the product includes directing the air flow along a first side of
at least one of the warm phase change plate and the cold phase
change plate in a first direction and directing the air flow along
a second side of the at least one of the warm phase change plate
and the cold phase change plate in a second direction; and wherein
the second direction is substantially opposite the first
direction.
6. The method of claim 1, further comprising reducing natural
circulation flow across at least one of the warm phase change plate
and the cold phase change plate.
7. The method of claim 6, wherein reducing natural circulation flow
across at least one of the warm phase change plate and the cold
phase change plate includes at least one of providing an air trap
associated with at least one of the warm phase change plate and the
cold phase change plate and closing said at least one flapper
valve.
8. The method of claim 7, wherein providing the air trap includes
providing at least one of a downwardly extending wall at least
partially interposing the warm phase change plate and the interior
storage space, and an upwardly extending wall at least partially
interposing the cold phase change plate and the interior storage
space.
9. The method of claim 1, further comprising transporting the
container from a first location to a second location while the
product remains within the interior storage space.
10. A method of storing a product in a container, the method
comprising: operating a refrigeration system comprising at least
one evaporator coil extending through an interior of a cold phase
change plate associated with an interior storage space of a
container to cool the cold phase change plate, wherein the
container comprises an enclosure constructed of insulated walls,
wherein the interior storage space is within the enclosure, wherein
the cold phase change plate is disposed within the enclosure and is
arranged for selective thermal communication with the interior
storage space, and wherein the refrigeration system is powered from
a first external source of electrical power; operating a heater in
thermal contact with a warm phase change plate associated with the
interior storage space to heat the warm phase change plate, wherein
the warm phase change plate is disposed within the enclosure and is
arranged for selective thermal communication with the interior
storage space, wherein the heater is powered from the first
external source of electrical power; placing a product in the
interior storage space; disconnecting the refrigeration system and
the heater from the first external source of electrical power; and
controlling a temperature associated with the interior storage
space by measuring the temperature associated with the interior
storage space; and selectively operating at least one of a cooling
fan arranged to cause airflow across the cold phase change plate
and a warming fan arranged to cause airflow across the warm phase
change plate if the temperature associated with the interior
storage space departs from a predetermined temperature range,
wherein the at least one cooling fan and the at least one warming
fan are powered from a rechargeable battery associated with the
container, and wherein at least one flapper valve is arranged to
selectively permit and obstruct airflow about at least one of said
warm phase change plate and said cold phase change plate where said
at least one flapper valve is propelled to an open position when
said at least one cooling fan or said at least one warming fan is
operating; wherein the refrigeration unit and the heater are not
operable while disconnected from the first external source of
electrical power.
11. The method of claim 10, further comprising, prior to operating
the refrigeration system and operating the heater, connecting the
refrigeration system and the heater to the first external source of
electrical power.
12. The method of claim 11, further comprising, after disconnecting
the refrigeration system and the heater from the first external
source of electrical power, loading the container into a
vehicle.
13. The method of claim 12, wherein loading the container into a
vehicle includes loading the refrigeration system and the heater
into the vehicle, the refrigeration system and the heater being
mounted to the container.
14. The method of claim 13, further comprising, transporting the
container from a first location to a second location using the
vehicle; and at the second location, conditioning at least one of
the cold phase change plate and the warm phase change plate.
15. The method of claim 14, further comprising, prior to
conditioning the at least one of the cold phase change plate and
the warm phase change plate at the second location, connecting at
least one of the refrigeration unit and the heater to a second
external source of electrical power.
16. The method of claim 15, wherein the container further comprises
an equipment section substantially adjacent to the enclosure; and
wherein at least a portion of the refrigeration system is disposed
in the equipment section.
17. A method of operating a temperature-controlled cargo container,
the method comprising: conditioning a cold phase change plate
disposed within an insulated enclosure using a refrigeration system
comprising at least one evaporator coil extending through an
interior of the cold phase change plate, wherein the enclosure is a
component of a temperature-controlled cargo container, and wherein
the cold phase change plate comprises a cold phase change solution
having a cold phase change solution melting point; conditioning a
warm phase change plate disposed within the insulated enclosure
using a heater in thermal contact with the warm phase change plate,
wherein an insulated divider wall interposes cold phase change
plate and the warm phase change plate, and wherein the warm phase
change plate comprises a warm phase change solution having a warm
phase change solution melting point, and wherein the warm phase
change solution melting point is higher than the cold phase change
solution melting point; receiving a product in an interior storage
space of the temperature-controlled cargo container, wherein the
interior storage space is disposed within the enclosure, and
wherein the interior storage space is arranged for selective heat
exchange with the cold phase change plate and the warm phase change
plate; and controlling a temperature associated with the product
while the refrigeration system and the heater are not operated,
including monitoring the temperature associated with the product;
if the temperature associated with the product rises above a target
temperature range, operating a cooling fan arranged to cause air
flow across the cold phase change plate by drawing air from the
interior storage space through a separator wall at least partially
interposing the interior storage space and the cold phase change
plate, flowing the air past the cold phase change plate, and
discharging the air into the interior storage space; and if the
temperature associated with the product falls below the target
temperature range, operating a warming fan associated with causing
air flow across the warm phase change plate by drawing air from the
interior storage space through a separator wall at least partially
interposing the interior storage space and the warm phase change
plate, flowing the air past the warm phase change plate, and
discharging the air into the interior storage space, and wherein at
least one flapper valve is arranged to selectively permit and
obstruct airflow about at least one of said warm phase change plate
and said cold phase change plate where said at least one flapper
valve is propelled to an open position when said at least one
cooling fan or said at least one warming fan is operating.
18. The method of claim 17, wherein at least one of the cold phase
change solution and the warm phase change solution comprises a
eutectic material.
19. The method of claim 17, wherein controlling the temperature
associated with the product includes directing the air flow along a
first side of the warm phase change plate in a first direction and
directing the air flow along a second side of the warm phase change
plate in a second direction; and wherein the second direction is
substantially opposite the first direction.
20. The method of claim 17, wherein controlling the temperature
associated with the product includes directing the air flow along a
first side of the cold phase change plate in a first direction and
directing the air flow along a second side of the cold phase change
plate in a second direction; and wherein the second direction is
substantially opposite the first direction.
21-29. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. patent
application Ser. No. 12/705,803, filed Feb. 15, 2010, U.S.
Provisional Application No. 61/244,232, filed Sep. 21, 2009, and
PCT/US10/49246, filed Sep. 17, 2010, which are incorporated by
reference.
BACKGROUND
[0002] The present disclosure is directed to containers for
controlling the temperature of a product placed therein and methods
of using temperature controlled cargo containers.
[0003] The following documents may be related to cargo containers
and/or temperature controlled transport: U.S. Pat. Nos. 3,180,403;
4,462,461; 5,561,986; 6,020,575; 6,281,797; 6,694,765; 6,865,516;
and 7,501,944; and U.S. Patent Application Publication No.
2007/0175236, and are incorporated by reference into this
Background section.
SUMMARY
[0004] Some example temperature controlled cargo containers
according to the present disclosure may include one or more thermal
masses conditioned to temperatures above and/or below a target
temperature. Example thermal masses may include plates including
phase change materials, such as eutectic materials. One or more
fans may be selectively operated to circulate air in the cargo
container across one or more of the thermal masses to maintain the
temperature within the cargo container within a prescribed
temperature band. Some example temperature controlled cargo
containers may include refrigeration units and/or heaters for
regenerating the thermal masses while receiving power from an
external power source and/or may include one or more rechargeable
batteries for providing power during transport or storage
independent of external power sources.
[0005] In an aspect, a method of controlling the temperature of a
product may include placing a product in an interior storage space
of a container, where the container includes a warm phase change
plate and a cold phase change plate; and changing a temperature of
the interior storage space by causing airflow across at least one
of the warm phase change plate and the cold phase change plate.
[0006] In a detailed embodiment, changing the temperature of the
interior storage space may include sensing a temperature associated
with the product; if the temperature associated with the product is
above a target temperature range, operating a cooling fan
associated with causing air flow across the cold phase change
plate; and if the temperature associated with the product is below
the target temperature range, operating a warming fan associated
with causing air flow across the warm phase change plate. In a
detailed embodiment, operating the cooling fan associated with the
cold phase change plate may include drawing air from the interior
storage space through a separator wall at least partially
interposing the interior storage space and the cold phase change
plate, flowing the air through an open flapper valve past the cold
phase change plate, and discharging the air into the interior
storage space. In a detailed embodiment, operating the warming fan
associated with the warm phase change plate may include drawing air
from the interior storage space through a separator wall at least
partially interposing the interior storage space and the warm phase
change plate, flowing the air through an open flapper valve and
past the warm phase change plate, and discharging the air into the
interior storage space.
[0007] In a detailed embodiment, a method may include, prior to
changing a temperature of the interior storage space, conditioning
at least one of the warm phase change plate and the cold phase
change plate. In a detailed embodiment, conditioning the cold phase
change plate may include operating a refrigeration unit to cause
freezing of a cold phase change solution within the cold phase
change plate. In a detailed embodiment, conditioning the warm phase
change plate may include operating a heater to melt a warm phase
change solution within the warm phase change plate.
[0008] In a detailed embodiment, changing a temperature of the
interior storage space may include directing the airflow along a
first side of the at least one of the warm phase change plate and
the cold phase change plate in a first direction and directing the
airflow along a second side of the at least one of the warm phase
change plate and the cold phase change plate in a second direction,
where the second direction may be substantially opposite the first
direction.
[0009] In a detailed embodiment, a method may include reducing
natural circulation flow across at least one of the warm phase
change plate and the cold phase change plate. In a detailed
embodiment, reducing natural circulation flow across at least one
of the warm phase change plate and the cold phase change plate may
include providing flapper valves and an air trap associated with at
least one of the warm phase change plate and the cold phase change
plate. In a detailed embodiment, providing the air trap may include
providing at least one of a downwardly extending wall at least
partially interposing the warm phase change plate and the interior
storage space, and an upwardly extending wall at least partially
interposing the cold phase change plate and the interior storage
space.
[0010] In a detailed embodiment, a method may include transporting
the container from a first location to a second location while the
product remains within the interior storage space.
[0011] In an aspect, a method of storing a product in a container
may include operating a refrigeration system to cool a cold phase
change plate associated with an interior storage space of a
container; operating a heater to heat a warm phase change plate
associated with the interior storage space; placing a product in
the interior storage space; measuring a temperature associated with
the interior storage space; and selectively operating at least one
fan to cause airflow across at least one of the cold phase change
plate and the warm phase change plate if the temperature associated
with the interior storage space departs from a predetermined
temperature range.
[0012] In a detailed embodiment, a method may include, prior to
operating the refrigeration system and operating the heater,
connecting the refrigeration system and the heater to a first
external source of electrical power. In a detailed embodiment, a
method may include, after operating the refrigeration system and
operating the heater, disconnecting the refrigeration system and
the heater from the first external source of electrical power. In a
detailed embodiment, a method may include, after disconnecting the
refrigeration system and the heater from the first external source
of electrical power, loading the container into a vehicle. In a
detailed embodiment, loading the container into a vehicle may
include loading the refrigeration system and the heater into the
vehicle, the refrigeration system and the heater being mounted to
the container. In a detailed embodiment, a method may include
transporting the container from a first location to a second
location using the vehicle; and, at the second location,
conditioning at least one of the cold phase change plate and the
warm phase change plate. In a detailed embodiment, a method may
include, prior to conditioning the at least one of the cold phase
change plate and the warm phase change plate at the second
location, connecting at least one of the refrigeration unit and the
heater to a second external source of electrical power. In a
detailed embodiment, a method may include, after the refrigeration
unit and the heater have been disconnected from the first external
source of electrical power and prior to connecting the
refrigeration unit and the heater to the second external source of
electrical power, operating the at least one fan using power
supplied from a rechargeable battery associated with the
container.
[0013] In an aspect, a temperature controlled container may include
an interior space for receiving a product; a warm phase change
plate arranged for selective heat exchange with the interior space;
and a cold phase change plate arranged for selective heat exchange
with the interior space.
[0014] In a detailed embodiment, the warm phase change plate and
the cold phase change plate may be at least partially separated
from the interior space by a separator wall. In a detailed
embodiment, a temperature controlled cargo container may include a
first fan selectively operable to cause forced convection between
the interior space and the warm phase change plate; and a second
fan selectively operable to cause forced convection between the
interior space and the cold phase change plate. In a detailed
embodiment, the cold phase change plate may include a first phase
change solution, and the warm phase change plate may include a
second phase change solution. In a detailed embodiment, a melting
point of the second phase change solution may be higher than a
melting point of the first phase change solution. In a detailed
embodiment, a target temperature range may lie between the melting
point of the first phase change solution and the melting point of
the second phase change solution. In a detailed embodiment, the
melting point of the first phase change solution may be about
-5.5.degree. C., and the melting point of the second phase change
solution may be about 15.degree. C. In a detailed embodiment, the
target temperature range may be about 2-8.degree. C.
[0015] In an aspect, a container may include an interior space for
receiving a product; a phase change plate arranged for selective
heat exchange with the interior space; and a trap arranged to
reduce natural convection heat transfer between the phase change
plate and the interior space while allowing forced convection heat
transfer between the phase change plate and the interior space.
[0016] In a detailed embodiment, the phase change plate may include
a cold phase change plate and/or the trap may include an upwardly
extending wall at least partially interposing the interior space
and the cold phase change plate. In a detailed embodiment, the trap
may include a P-trap. In a detailed embodiment, a container may
include a fan configured to cause air flow from the interior space,
across the cold phase change plate, and into the interior
space.
[0017] In a detailed embodiment, the phase change plate may include
a warm phase change plate and/or the trap may include a downwardly
extending wall at least partially interposing the interior space
and the warm phase change plate. In a detailed embodiment, the trap
may include a P-trap. In a detailed embodiment, a container
includes a fan configured to cause air flow from the interior
space, across the warm phase change plate, and into the interior
space.
[0018] In an aspect, a container may include a phase change plate
including a first side and a second side and/or a flow path
arranged to direct airflow along the first side in a first
direction and then along the second side in a second direction,
where the second direction may be substantially opposite the first
direction.
[0019] In a detailed embodiment, the first side may be
substantially opposite the second side. In a detailed embodiment, a
container may include at least one fan configured to cause the
airflow through the flow path. In a detailed embodiment, the phase
change plate may be at least partially separated from an interior
storage space of the container by a wall.
[0020] In a detailed embodiment, the phase change plate may include
at least one augmented surface. In a detailed embodiment, the
augmented surface may include at least one internally extending
fin.
[0021] In an aspect, a shipping system may include a container
including an interior space for receiving a product, a warm phase
change plate arranged for selective heat exchange with the interior
space, and a cold phase change plate arranged for selective heat
exchange with the interior space; a refrigeration system mounted to
the container and configured to cool the cold phase change plate;
and a heating system configured to heat the warm phase change
plate.
[0022] In a detailed embodiment, a shipping system may include a
data logger configured to record data pertaining to the container.
In a detailed embodiment, the data may include a temperature
associated with the interior space.
[0023] In a detailed embodiment, the warm phase change plate may
include a cold phase change material having a melting point of
about -5.5.degree. C. In a detailed embodiment, the cold phase
change plate may include a warm phase change material having a
melting point of about 15.degree. C. In a detailed embodiment, the
heating system may include at least one electrical resistance
heater in thermal communication with the warm phase change
plate.
[0024] In an aspect, a container for shipping pharmaceuticals may
include a warm phase change plate and/or a cold phase change
plate.
[0025] In a detailed embodiment, the container may include an
interior storage space for pharmaceuticals, the interior storage
space being in selective thermal communication with the warm phase
change plate and/or the cold phase change plate. In a detailed
embodiment, a container may include a warming fan configured to
cause airflow across the warm phase change plate and/or a cooling
fan configured to cause airflow across the cold phase change plate.
In a detailed embodiment, the cold phase change plate may include a
cold eutectic material having a melting point of about -5.5.degree.
C. and/or the warm phase change plate may include a warm eutectic
material having a melting point of about 15.degree. C. In a
detailed embodiment, a container a refrigeration system arranged to
cool the cold phase change plate and/or a heater arranged to heat
the warm phase change plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The detailed description refers to the following figures in
which:
[0027] FIG. 1 is an isometric view of an example temperature
controlled cargo container;
[0028] FIG. 2 is an overhead cross-sectional view of an example
temperature controlled cargo container;
[0029] FIG. 3 is an elevational cross-sectional view of an example
temperature controlled cargo container;
[0030] FIG. 4 is an elevational cross-sectional view of an example
temperature controlled cargo container with open flapper valve;
[0031] FIG. 5 is an elevational cross-sectional view of an example
temperature controlled cargo container with closed flapper
valve;
[0032] FIG. 6 is an elevational cross-sectional view of an example
temperature controlled cargo container;
[0033] FIG. 7 is an elevational cross-sectional view of an example
temperature controlled cargo container with open flapper valve;
[0034] FIG. 8 is an elevational cross-sectional view of an example
temperature controlled cargo container with closed flapper
valve;
[0035] FIG. 9 is a cross-sectional view of a wall of an example
temperature controlled cargo container;
[0036] FIG. 10 is cross-sectional view of an example phase change
plate for a temperature controlled cargo container;
[0037] FIG. 11 is a schematic diagram of an example refrigeration
system for a temperature controlled cargo container;
[0038] FIG. 12 is a schematic diagram of an example electrical
system for a temperature controlled cargo container;
[0039] FIG. 13 is a schematic diagram illustrating an example
temperature controlled cargo container configured for use with
external conditioning sources;
[0040] FIG. 14 is a is a schematic diagram illustrating an example
temperature controlled cargo container configured for use with
removable phase change plates; and
[0041] FIG. 15 is a perspective view of two example temperature
controlled cargo containers on an aircraft pallet; all arranged in
accordance with at least some aspects of the present
disclosure.
DETAILED DESCRIPTION
[0042] The present disclosure includes, inter alia, temperature
controlled cargo containers and methods for using temperature
controlled cargo containers.
[0043] The present disclosure contemplates that some products
(e.g., pharmaceutical products) may be transported (e.g., by
ground, sea, and/or air modes) and may be exposed to ambient
conditions outside of an allowable product temperature range during
such transportation and/or during storage. Temperature excursions
outside of the allowable product temperature range may
detrimentally affect a product, such as by reducing the efficacy
and/or shelf life of a pharmaceutical product.
[0044] Some example temperature controlled cargo containers
according to the present disclosure may be configured to maintain a
product located therein within an allowable product temperature
range while the temperature controlled cargo container is exposed
to various ambient conditions. For example, some example
temperature controlled cargo containers may be configured to
maintain pharmaceutical products within an interior storage space
at about 5.degree. C. (e.g., between about 2.degree. C. and about
8.degree. C.) during ground, sea, and/or air transportation and/or
during temporary and/or long-term storage. Some example temperature
controlled cargo containers may maintain an interior storage space
at about 5.degree. C. for about 72 hours when the ambient
temperature is about 30.degree. C. while operating independently
from external power sources and/or cooling sources. Some example
temperature controlled cargo containers may maintain an interior
storage space at about 5.degree. C. during ambient temperature
excursions, such as from about -40.degree. C. to about +60.degree.
C.
[0045] Referring to FIGS. 1-8, an example temperature controlled
cargo container 100 according to the present disclosure may include
a generally rectangular enclosure 101 and/or an equipment section
111, which may be disposed substantially adjacent to enclosure 101.
Enclosure 101 may include walls 102 and/or a door 103, which may be
pivotably affixed to walls 102 by a hinge 109. In some example
embodiments, door 103 and equipment section 111 may be disposed on
generally opposite sides of enclosure 101. A door sealing assembly
associated with door 103 may include thermal breaks on one or both
sides of the door/enclosure interface, redundant compression bulb
gaskets, and/or multi-point (e.g., three-point) draw latches which
may fix the gasket compression depth. Enclosure 101 and/or
equipment section 111 may be mounted on a pallet base 113, which
may facilitate handling of temperature controlled cargo container
100 by forklifts and/or other material handling equipment, for
example. An interior storage space 104 within enclosure 101 (which
may be accessible via door 103) may receive a product 106, such as
a pharmaceutical product.
[0046] Some example temperature controlled cargo containers 100 may
include at least one cold thermal mass and/or at least one warm
thermal mass disposed within enclosure 101. For example, a cold
phase change plate 112 and/or a warm phase change plate 212 may be
mounted within enclosure, such as generally opposite door 103. Cold
phase change plate 112 may comprise a cold phase change material
(PCM), which may include a eutectic material, having a desired
melting point (e.g., about -5.5.degree. C. (e.g., about 5.5.degree.
C. below 0.degree. C.)). Warm phase change plate 212 may comprise a
warm phase change material, which may include a eutectic material,
having a desired melting point (e.g., about 15.degree. C.).
[0047] Some example temperature controlled cargo containers may
include one or more thermal masses (e.g., cold phase change plates
112 and/or warm phase change plates 212) having sufficient thermal
capacitance (e.g., total energy capacity) to accommodate the total
energy requirements of a design condition. Some exemplary
temperature controlled cargo containers may include one or more
thermal masses having sufficient surface area and/or thermal
conductivity to accommodate the peak heat transfer rate
requirements of a design condition.
[0048] Some example phase change plates may be constructed from,
for example, galvanized steel, aluminum, and/or stainless steel. In
some example embodiments, such materials may be welded. An example
phase change plate may have a generally flattened, rectangular
shape with dimensions of about 4.5''.times.6.5''.times.40''. As
used herein, "plate" refers to generally rectangular shapes as well
as any other desirable shape.
[0049] Some example temperature controlled cargo containers 100
according to the present disclosure may be operated as follows.
Warm phase change plate 212 and/or cold phase change plate 112 may
be conditioned. As used herein, "conditioning" refers to freezing
the cold phase change material of cold phase change plate 112
and/or melting the warm phase change material of warm phase change
plate 212. Product 106 may be placed in interior storage space 104
of temperature controlled cargo container 100. The temperature of
interior storage space 104 may be controlled by causing airflow
across at least one of warm phase change plate 212 and cold phase
change plate 112. Specifically, airflow across cold phase change
plate 112 may cool interior storage space 104 and/or airflow across
warm phase change plate 212 may warm interior storage space
104.
[0050] In some example temperature controlled cargo containers 100,
one or more phase change plates 112, 212 may be mounted such that
they are at least partially thermally insulated from one or more
other phase change plates 112, 212 and/or from interior storage
space 104. For example, a divider wall 107, which may be insulated,
may interpose cold phase change plate 112 and warm phase change
plate 212. An interior separator wall 105, which may be insulated,
may at least partially interpose interior storage space 104 and
cold phase change plate 112 and/or warm phase change plate 212.
Thus, in some example embodiments, interior storage space 104 may
be generally rectangular and/or may be substantially defined by
door 103, walls 102, and/or interior separator wall 105. Interior
separator wall 105 may not extend fully between walls 102, thereby
allowing thermal communication between interior space 104 and phase
change plates 112, 212 when desired.
[0051] In some example temperature controlled cargo containers 100,
one or more cooling fans 108 may be selectively operable to cause
flow of air 110 past a cold thermal mass, such as cold phase change
plate 112, and/or one or more warming fans 208 may be selectively
operable to cause flow of air 210 past a warm thermal mass, such as
warm phase change plate 212. As illustrated in FIGS. 3-8, fans 108,
208 may be arranged draw air 110, 210 from interior storage space
104, through separator wall 105, and past phase change plate 112,
212 and/or to discharge air 110, 210 into interior storage space
104. Some example embodiments may include at least two cooling fans
108 and/or at least two warming fans 208, which may allow continued
operation of temperature controlled cargo container 100 if one of
cooling fans 108 and/or one of warming fans 208 fails. Some example
cooling fans 108 and/or warming fans 208 may include fans driven by
low voltage DC motors.
[0052] Some example temperature controlled cargo containers 100 may
be configured to selectively direct air flow 110, 210 past one or
more phase change plates 112, 212 such that the air 110, 210 passes
along one side of phase change plate 112, 212 in a first direction
and passes along an opposite side of phase change plate 112, 212 in
an opposite direction. For example, referring to FIGS. 3-5, air 110
may flow generally downward along a front face 112A of cold phase
change plate 112 and may flow generally upward along a rear face
112B of cold phase change plate 112. Similarly, referring to FIGS.
6-8, air 210 may flow generally upward along a front face 212A of
warm phase change plate 212 and may flow generally downward along a
rear face 212B of warm phase change plate 212. The present
disclosure contemplates that such a flow arrangement may reduce the
temperature variation in the phase change materials within cold
phase change plate 112 and/or warm phase change plate 212 as
measured along axes generally parallel with the air flow.
[0053] Some exemplary temperature controlled cargo containers may
be designed to reduce natural convection (e.g., fluid motion caused
by density differences in the fluid due to temperature gradients)
past one or more phase change plates 112, 212. For example,
referring to FIG. 3, an upwardly extending wall 114 (which may be
referred to as a "false wall") may be provided near cold phase
change plate 112, such as between cold phase change plate 112 and
separator wall 105. Wall 114 may prevent cooler, denser air near
the cold phase change plate 112 from settling into the interior
storage space 104. Similarly, referring to FIG. 6, a downwardly
extending wall 214 (which may be referred to as a "false wall") may
be provided near warm phase change plate 212, such as between warm
phase change plate 212 and separator wall 105. Wall 214 may prevent
warmer, less dense air near the warm phase change plate 212 from
rising into the interior storage space 104. Such walls 114, 214 may
shape the respective air flow paths into P-traps 114A, 214A. Some
example embodiments may direct air flow in a generally serpentine
path past phase change plates 112, 212. In some example
embodiments, walls 105, 114, 214 and/or phase change plates 112,
212 may provide a generally S-shaped serpentine air flow path.
[0054] Some exemplary embodiments may reduce natural convection
using one or more devices in addition to or instead of a P-trap.
For example, some example embodiments may include one or more
dampers and/or shutters, which may be selectively opened and/or
shut by pneumatic, spring, electromechanical (such as solenoid or
motor) and/or other similar actuators. Such dampers and/or shutters
may be mounted to obstruct a natural convection flow path, such as
adjacent to separator wall 105.
[0055] For example, as shown in FIGS. 4 and 5, natural convection
may be significantly reduced when desired by providing a flapper
valve 115 disposed in the airflow path. Flapper valve 115 may be
hingedly attached to a flapper valve support 119 which may be
installed near the cold phase change plate 112. In one embodiment,
the flapper valve 115 and flapper valve support may be disposed
substantially above the upwardly extending wall 114. The flapper
valve 115 may also include a flapper valve backer 117 that may
contact and may assist with the closing of valve 115 when desired.
In one embodiment, as shown in FIGS. 5 and 6, flapper valve backer
117 may be disposed on the top end of upwardly extending wall 114
substantially aligned with and underneath flapper valve 115 and may
be separated from the flapper valve by a portion of the airflow
path. As shown in FIG. 4, when the cooling fan 108 is operating
causing the air 110 to flow near the cold phase change plate 112 in
a generally serpentine air flow path the air may flow with
sufficient pressure to open the flapper valve 115 and pivot it away
from flapper valve backer 117 so as to allow airflow to pass
between the flapper valve 115 and the backer 115. As shown in FIG.
5, when the cooling fan 108 is off, the airflow caused by the fan
substantially ceases allowing the flapper valve 115 to close and
contact flapper valve backer 115. As shown in FIG. 5, when the
flapper valve 115 is closed it may substantially block the air flow
path 110. As such, when additional cooling in the interior storage
space 104 is no longer required, and the cooling fan 108 is shut
off, the flapper valve 115 closes against the backer 117 to
obstruct convection from the cooling plate 112 into the interior
storage space 104.
[0056] Similarly, as shown in FIGS. 6 and 7, natural convection may
be significantly reduced when desired by providing a flapper valve
215 disposed in the airflow path near the warm phase change plate
212. Flapper valve 215 may be hingedly attached to a flapper valve
support 219 which may be installed near the warm phase change plate
212. In one embodiment, the flapper valve 215 and flapper valve
support may be disposed substantially above the interior separator
wall 105. Just as with the flapper valve near the cold phase change
plate 112, the flapper valve 215 may also include a flapper valve
backer 217 that may contact and may assist with the closing of
valve 215 when desired. In one embodiment, as shown in FIGS. 7 and
8, flapper valve backer 217 may be disposed on the top end of
interior separator wall 105 substantially aligned with and
underneath flapper valve 215 and may be separated from the flapper
valve by a portion of the airflow path. As shown in FIG. 6, when
the warming fan 208 is operating causing the air 210 to flow near
the warm phase change plate 212 in a generally serpentine air flow
path the air may flow with sufficient pressure to open the flapper
valve 215 and pivot it away from flapper valve backer 217 so as to
allow airflow to pass between the flapper valve 215 and the backer
215. As shown in FIG. 7, when the warming fan 208 is off, the
airflow caused by the fan substantially ceases allowing the flapper
valve 215 to close and contact flapper valve backer 215. As shown
in FIG. 7, when the flapper valve 215 is closed it may
substantially block the air flow path 210. As such, when additional
warming in the interior storage space 104 is no longer required,
and the warming fan 208 is shut off, the flapper valve 215 closes
against the backer 217 to obstruct convection from the warming
plate 212 into the interior storage space 104.
[0057] Any number of sufficiently resilient and flexible materials
may be selected for the flapper valve 115, 215 including but not
limited to a variety of plastics, rubber, silicon rubber,
elastomers, or coated fabrics. To provide additional force to
releasably close the flapper valve 115, 215 when the circulating
fans 108, 208 stop operating and it is desired to close the flapper
valves, the flapper valves 115, 215 may be at least partially
comprised of ferrous material and the flapper valve backer 117, 217
may include a magnet that attracts and assists with drawing the
flapper valves 115, 215 against the flapper valve backer 117, 217.
It should be understood that the magnetic components of flapper
valve 115, 215 and flapper valve backer 117, 217 could be reversed
such that the flapper valve 115, 215 includes a magnet and the
flapper valve backers 117, 217 include ferrous material that would
cause the flapper valve 115, 215 with magnets to pull and attach to
the backers 117, 217 when the circulating fan 108, 208 is stopped.
It is contemplated that various known cooperative magnetic
arrangements may be employed such as varying the magnetic strength
of the backer 117, 217 or flapper valve 115, 215 at different
points of an associated magnet to optimize the ability of the valve
115, 215 to stay open during circulating fan 108, 208 operation and
to close when the fan operation is stopped.
[0058] Walls 102 may be insulated, such as by vacuum panels. In
some example embodiments, walls 102 may have a thickness 401 of
about 4'' and/or may have an R-value (a measure of thermal
resistance) of about R-70 to resist thermal energy transfer between
interior storage space 104 and the ambient environment. Referring
to FIG. 9, an example wall may include an exterior skin 402 and/or
an interior skin 404. Exterior skin 402 and/or interior skin 404
may comprise aluminum and/or may have a thickness of about 0.030'',
for example. An insulating foam layer, such as poured foam 406, may
be provided adjacent to exterior skin 402. Poured foam 406 may have
a thickness 408 of about 2'', for example. A vacuum panel 410 may
be provided adjacent to poured foam 406. Vacuum panel 410 may have
a thickness 412 of about 1'', for example. An insulating foam
layer, such as poured foam 414, may be provided between vacuum
panel 410 and interior skin 404. Poured foam 414 may have a
thickness 416 of about 1/2'' or about 3/4'', for example. In some
example embodiments, poured foam 414 may be replaced by a foam
board, which may be bonded to vacuum panel 410 and/or interior skin
404, such as using an adhesive.
[0059] In some example temperature controlled cargo containers 100,
walls 102 may comprise a stressed skin construction, which may
provide a relatively high strength with relatively low weight. In
some example embodiments, inner layers (e.g., poured foam 406,
vacuum panel 410, and/or poured foam 414) and/or outer layers
(e.g., exterior skin 402 and/or interior skin 404) may be disposed
such that layers may not slide relative to others layer. Such a
construction may provide a wall structure having relatively high
area moment of inertia, which may add considerable structural
strength to the product with minimal additional weight, while
allowing a "flex" component to the structure.
[0060] Some exemplary temperature controlled cargo containers 100
may include one or more thermal masses including one or more
augmented surfaces, such as fins and/or other similar heat transfer
enhancing features, internally and/or externally. For example,
referring to FIG. 10, an example phase change plate 302 may include
one or more thermally conductive fins 304 extending through the
thickness 306 of the plate 302, such as substantially from one wall
308 to the opposite wall 310, which may enhance heat transfer to
and/or from phase change material 312 (e.g., a eutectic solution
and/or other phase change material) between walls 308, 310. In some
exemplary embodiments, one or more fins 304 may be mounted to the
first wall 308 and may seat against the second wall 310 when the
phase change plate 302 is assembled.
[0061] It is within the scope of the disclosure to utilize fins 304
or other conductive augmentations of any cross section or profile.
The present disclosure contemplates that some example phase change
materials may be relatively poor thermal conductors and that
utilizing conductive augmentations within the phase change material
may reduce the temperature gradient across the thickness of the
phase change material. Some example phase change plates may include
refrigerant lines (and/or lines for other materials used to
condition phase change materials) and/or electrical resistance
heaters extending therethrough for conditioning the phase change
material.
[0062] FIG. 11 is a schematic diagram of an example refrigeration
system 500 which may be used in connection with an example
temperature controlled cargo container 100. In some example
embodiments, refrigeration system 500 may include two substantially
independent refrigeration units 500A, 500B, thus providing
redundancy. Refrigeration units 500A, 500B may be substantially
identical and, for purposes, of clarity, FIG. 11 is discussed with
reference to refrigeration unit 500A with the understanding that
refrigeration unit 500B may include corresponding components. An
individual refrigeration unit 500A may include a compressor 504, a
condenser 506, a fan 508 configured to provide airflow across
condenser 506, and/or an expansion valve 512.
[0063] In some example embodiments, an individual refrigeration
unit 500A may include an evaporator 502 disposed in thermal
communication with one or more cold phase change plates 112 (e.g.,
with evaporator coils extending through the interior of cold phase
change plate 112). In some example embodiments, evaporators 502
associated with more than one individual refrigeration unit 500A,
500B may be in thermal contact with the same cold phase change
plate 112, which may increase the reliability of temperature
controlled cargo container 100 because the failure of a single
refrigeration unit 500A, 500B may not prevent cold phase change
plate 112 from being conditioned. Each of refrigeration units 500A,
500B may be sized to be capable of conditioning one or more cold
phase change plates 112 without the other system operating.
However, the time to condition one or more cold phase change plates
112 with a single refrigeration unit 500A, 500B operating may be
longer than the time to condition one or more cold phase change
plate 112 with both refrigeration units 500A, 500B operating. In
some example embodiments, one or more cold phase change plates 112
and/or evaporator 502 may be located within enclosure 101 and/or
many of the remaining components of refrigeration units 500A, 50013
may be disposed in equipment section 111.
[0064] FIG. 12 is a schematic diagram of an example electrical
system 600 associated with a temperature controlled cargo container
100 according to the present disclosure. An external power source
connection 602 may provide power to one or more power supplies 604,
606, 608 and/or a battery charger 610. Power supply 604 may feed
refrigeration unit 500A and/or warm plate regenerator 612 (e.g., an
electrical resistance heater in thermal contact with warm phase
change plate 212). Power supply 606 may feed refrigeration unit
500B and/or warm plate regenerator 614. Battery charger 610 may
provide a charging current to rechargeable battery 616, which may
feed control electronics 618, warming fans 208A, 20813, and/or
cooling fans 108A, 108B. Power supply 608 may also feed control
electronics 618, warming fans 208A, 208B, and/or cooling fans 108A,
108B.
[0065] Some example temperature controlled cargo containers 100 may
be operable in a recharge mode (also referred to as an active mode)
and/or a transport move (also referred to as a passive mode). In an
example recharge mode, a temperature controlled cargo container 100
may connected to an external power source, such as standard
electric line power (e.g., 100-230 VAC, 50 or 60 Hz).
[0066] In the recharge mode, refrigeration units 500A, 500B may
cool cold phase change plate 112, which may freeze the cold phase
change material of cold phase change plate 112. Similarly, one or
more warm plate regenerators 612, 614 (e.g., electrical resistance
heaters) may heat warm phase change plate 212, which may melt the
warm phase change material of warm phase change plate 212.
Refrigeration units 500A, 500B and/or regenerators 612, 614 may be
powered from the external power source. Rechargeable battery 616
(such as a 12 V lead-acid battery) may be charged from the external
power source. In some example embodiments, the components within
box 620 as well as the components within box 622 of FIG. 12 may be
powered from the external power source when in the recharge
mode.
[0067] Referring to FIG. 13, some example temperature controlled
cargo containers according to the present disclosure may be
constructed to interface with external conditioning systems. Such
embodiments may or may not include refrigeration units 500A, 500B,
warm plate regenerators 612, 614, and/or equipment section 111. As
illustrated in FIG. 13, an example temperature controlled cargo
container 100A holding product 106A may be generally similar to
temperature controlled cargo container 100 described above.
Temperature controlled cargo container 100A may be configured for
use with externally supplied conditioning for cold phase change
plate 112A and/or warm phase change plate 212A. For example, cold
phase change plate 112A may be conditioned by a chilled fluid 802
(e.g., a water-ethylene glycol solution at about -5.degree. C.)
circulated through a heat exchanger 800 in thermal contact with
cold phase change plate 112A. Chilled fluid 802 may be propelled by
a pump 804 via through appropriate conduits, which may include
fittings 806, 808 (e.g., quick disconnect fittings). A
refrigeration system 810, which may be powered from an external
power source 812, may remove heat from chilled fluid 802 using a
heat exchanger 814. In some example embodiments, refrigeration
system 810 may include one or more vapor-compression refrigeration
systems, which may be generally similar to refrigeration units
500A, 500B.
[0068] Similarly, warm phase change plate 212A may be conditioned
by a warmed fluid 902 (e.g., a water-ethylene glycol solution at
about 25.degree. C.) circulated through a heat exchanger 900 in
thermal contact with warm phase change plate 212A. Warmed fluid 902
may be propelled by a pump 904 via through appropriate conduits,
which may include fittings 906, 908 (e.g., quick disconnect
fittings). A heater system 910, which may be powered from an
external power source 912, may remove heat from chilled fluid 902
using a heat exchanger 914. In some example embodiments, heater
system 910 may include one or more electrical resistance heaters in
thermal contact with warmed fluid 902 in heat exchanger 914.
[0069] Referring to FIG. 14, Some example temperature controlled
cargo containers 100B according to the present disclosure may
include one or more readily removable and/or replaceable cold phase
change plates 112B and/or warm phase change plates 212B. Such
example embodiments may allow pre-conditioned cold phase change
plates 112B and/or warm phase change plates 212B to be installed
into temperature controlled cargo container 100B prior to
transport. In addition, such embodiments may permit replacement of
partially or fully expended cold phase change plates 112B and/or
warm phase change plates 212B with conditioned cold phase change
plates 112B and/or warm phase change plates 212B during extended
storage and/or during extended transport. Such embodiments may or
may not include refrigeration units 500A, 500B, warm plate
regenerators 612, 614, and/or equipment section 111. For example,
removable cold phase change plates 112B may be conditioned in an
environmental chamber 1002 (which may be maintained at about
-5.degree. C.) and/or removable warm phase change plates 212B may
be conditioned in an environmental chamber 1004 (which may be
maintained at about 15.degree. C.).
[0070] In an example transport mode, some example temperature
controlled cargo containers 100 may be disconnected from the
external power source and/or conditioning source. In the transport
mode, the temperature of interior storage space 104 may be
monitored, and one or more of fans 108A, 108B, 208A, 208B may be
selectively operated to circulate air across one or more cold phase
change plates 112 and/or one or more warm phase change plates 212
as necessary to maintain the temperature of interior storage space
104 within a prescribed temperature band (e.g., between about
2.degree. C. and about 8.degree. C.). For example, if the
temperature within the interior storage space 104 exceeds a
predetermined setpoint, fans 108A, 108B may be operated to
circulate air across cold phase change plate 112, which may cool
interior storage space 104. Similarly, if the temperature within
interior storage space 104 drops below a predetermined setpoint,
fans 208A, 208B may be operated to circulate air across warm phase
change plate 212, which may warm interior storage space 104. More
specifically, circulation of air across cold phase change plate 112
may transfer heat from the air to the cold phase change material,
which may cause the cold phase change material to melt. As the cold
phase change material melts, it may absorb from the air an amount
of heat equal to its latent heat of fusion. Similarly, circulation
of air across warm phase change plate 212 may transfer heat from
the warm phase change material to the air, which may cause the warm
phase change material to freeze. As the warm phase change material
freezes, it may transfer to the air an amount of heat equal to it
latent heat of fusion.
[0071] Control electronics 618 (e.g., temperature monitoring
components, fan control components, etc.) and/or fans 108A, 108B,
208A, 208B may be powered from the rechargeable battery 616 in the
transport mode. In some example embodiments, refrigeration units
500A, 500B used to cool cold phase change plates 112 and/or the
regenerator used to heat warm phase change plates 212 may not
operate during transport mode. In some example embodiments, the
components within box 622 of FIG. 12 may be powered from battery
616 during the transport mode.
[0072] In some example embodiments, various control electronics 618
(which may include a status panel) may be powered from rechargeable
battery 616 during the transport mode. The control electronics may
include, for example, a low power embedded industrial PC for low
power consumption and/or low EMI (electromagnetic interference).
The control electronics and/or status panel may be configured to
communicate the condition of the cargo unit to the user. For
example, a temperature of the interior storage space 104 may be
displayed and/or transmitted to a user. In some example
embodiments, a data logger may monitor and/or record the
temperature in the interior storage space 104. In some example
embodiments, the data logger may be independently powered by a
non-replaceable battery with an extended life, such as a three year
life.
[0073] Some exemplary temperature controlled cargo containers
according to the present disclosure may be configured to be
received within and/or on an air transport cargo unit for shipment
via air. For example, two exemplary 76 cubic foot capacity
temperature controlled cargo containers 100 may be placed inside an
L9 unit load device (ULD) for shipment aboard certain types of
aircraft. Similarly, as illustrated in FIG. 15, some example
temperature controlled cargo containers 100 may be transported in a
net/pallet configuration. One or more temperature controlled cargo
containers 100 may be placed on a generally flat pallet 700, which
may be referred to as a "cookie sheet" in the air transport
industry. Temperature controlled cargo containers 100 may be
fastened to pallet 700 using, for example, one or more straps 702
and/or nets 704. Pallet 700 with temperature controlled cargo
containers 100 thereon may be considered a ULD for air transport
purposes and/or may be readily loaded into and secured within an
aircraft (or other vehicle).
[0074] Some example temperature controlled cargo containers 100
according to the present disclosure may be configured to function
as a ULD in an air transport system. Such example embodiments may
be sized and/or shaped substantially the same as a ULD used by an
air carrier, and the air carrier may load such temperature
controlled cargo containers 100 in an aircraft in generally the
same manner as other ULDs.
[0075] Some example temperature controlled cargo containers 100 may
be sized to receive standard units of product. For example, an
example 76 cubic foot capacity temperature controlled cargo
container 100 may include an interior storage space 104 sized to
receive an about 40''.times.48''pallet containing about 250 lbs. of
product. In such an example embodiment, interior storage space 104
may have interior dimensions of about 46'' high.times.44''
wide.times.53'' deep. Such an example embodiment may have overall
dimensions of about 58'' high.times.52.75'' wide.times.80'' long,
and its tare weight may be about 1250 lbs.
[0076] Some example thermal masses comprising phase change
materials may include one or more of water, potassium nitrate,
ethylene glycol, propylene glycol, one or more alcohols (e.g.,
ethyl alcohol, methyl alcohol, and/or isopropyl alcohol), potassium
chloride, sodium borate, zinc, and/or ammonium chloride. In
general, it is within the scope of the present disclosure to
utilize one or more thermal masses comprising any materials capable
of accepting and/or delivering appropriate amounts of thermal
energy at appropriate rates to satisfy design conditions. Further,
it is within the scope of the present disclosure to utilize any
phase change materials providing desired melting points.
[0077] Some example temperature controlled cargo containers have
been described herein with reference to a target temperature of
about 5.degree. C., which may correspond to temperature range of
about 2.degree. C. to about 8.degree. C. Other example temperature
controlled cargo containers according to the present disclosure may
be configured to maintain a product located therein at colder
temperatures (e.g., about -20.degree. C., about -40.degree. C.,
about -80.degree. C., and/or about -100.degree. C.) or warmer
temperatures (e.g., about 25.degree. C., about 50.degree. C.,
and/or about 60.degree. C.). In general, temperature controlled
cargo containers according to the present disclosure may be
configured to maintain any desired interior temperature.
[0078] Some example temperature controlled cargo containers
according to the present disclosure may include warm and cold
thermal masses including phase change materials having melting
points differing from a target temperature by various amounts. For
example, a warm phase change material may have a melting point
about 15.degree. C. above a target temperature and a cold phase
change material may have a melting point about 15.degree. C. below
the target temperature. Similarly, the melting points of the warm
and cold phase change materials may differ from the target
temperature by any other desired amount (e.g., about 5.degree. C.,
about 10.degree. C., about 20.degree. C., about 25.degree. C.,
etc.). In some example embodiments, the melting point of the warm
phase change material may differ from the target temperature by a
greater (or lesser) amount than the cold phase change material
differs from the target temperature. For example, a warm phase
change material may have a melting point of about 10.degree. C.
about above a target temperature and a cold phase change material
may have a melting point of about 20.degree. C. below the target
temperature.
[0079] Some example temperature controlled cargo containers may be
operated as follows. A refrigeration system may be operated to cool
a cold phase change plate associated with an interior storage space
of a container. A heater may be operated to heat a warm phase
change plate associated with the interior storage space. A product
may be placed in the interior storage space. A temperature
associated with the interior storage space may be measured. At
least one fan may be selectively operated to cause airflow across
at least one of the cold phase change plate and the warm phase
change plate if the temperature associated with the interior
storage space departs from a predetermined temperature range.
[0080] As used herein, ambient conditions refer to the
environmental conditions to which a temperature controlled cargo
container is subject. For example, the ambient temperature for a
temperature controlled cargo container on an airport ramp may be
the outside air temperature at the ramp. As another example, the
ambient temperature for a temperature controlled cargo container
being transported in an aircraft at cruise altitude may be the
interior temperature of the aircraft where the temperature
controlled cargo container is stowed.
[0081] While exemplary embodiments have been set forth above for
the purpose of disclosure, modifications of the disclosed
embodiments as well as other embodiments thereof may occur to those
skilled in the art. Accordingly, it is to be understood that the
disclosure is not limited to the above precise embodiments and that
changes may be made without departing from the scope. Likewise, it
is to be understood that it is not necessary to meet any or all of
the stated advantages or objects disclosed herein to fall within
the scope of the disclosure, since inherent and/or unforeseen
advantages may exist even though they may not have been explicitly
discussed herein.
* * * * *