U.S. patent application number 09/878169 was filed with the patent office on 2002-12-12 for temperature controlled cabinet system and method employing a thermal barrier to thermally isolate the cabinet interior from the ambient environment.
Invention is credited to Faries, Durward I. JR..
Application Number | 20020184906 09/878169 |
Document ID | / |
Family ID | 25371521 |
Filed Date | 2002-12-12 |
United States Patent
Application |
20020184906 |
Kind Code |
A1 |
Faries, Durward I. JR. |
December 12, 2002 |
Temperature controlled cabinet system and method employing a
thermal barrier to thermally isolate the cabinet interior from the
ambient environment
Abstract
A temperature controlled cabinet system of the present invention
includes at least one heat pump, a controller assembly for
controlling system operation and a temperature sensor for measuring
a cabinet interior temperature. The heat pump heats and/or cools
the cabinet interior to maintain the cabinet interior at a desired
temperature in response to control signals from the controller
assembly. The cabinet system further includes a thermal barrier to
thermally isolate the cabinet interior from the ambient environment
and permit access to medical items contained within the cabinet.
The thermal barrier includes a plurality of strips that maybe
arranged in various fashions (e.g., overlapped, spaced from each
other a selected distance, etc.) to substantially impede or
minimize heat exchange between the cabinet interior and ambient
environment during intervals where the cabinet interior is exposed
to that environment (e.g., intervals where at least one cabinet
door is in an open state).
Inventors: |
Faries, Durward I. JR.; (Las
Vegas, NV) |
Correspondence
Address: |
EPSTEIN, EDELL, SHAPIRO, FINNAN & LYTLE, LLC
1901 RESEARCH BOULEVARD
SUITE 400
ROCKVILLE
MD
20850
US
|
Family ID: |
25371521 |
Appl. No.: |
09/878169 |
Filed: |
June 12, 2001 |
Current U.S.
Class: |
62/229 ;
62/265 |
Current CPC
Class: |
F25D 23/025 20130101;
F25D 2700/12 20130101; F25D 2400/36 20130101; A61J 1/165 20130101;
F25D 19/04 20130101 |
Class at
Publication: |
62/229 ;
62/265 |
International
Class: |
F25B 001/00; F25B
049/00; F25D 023/02 |
Claims
What is claimed is:
1. A temperature controlled cabinet system for storing medical
items and maintaining said medical items within a desired
temperature range comprising: a cabinet to receive at least one
medical item within a cabinet interior and including at least one
door to provide access to said cabinet interior; at least one heat
pump partially disposed within said cabinet interior to heat or
cool said cabinet interior; a temperature sensor disposed within
said cabinet interior to measure a cabinet interior temperature and
to generate a temperature signal indicating said measured cabinet
interior temperature; a controller assembly to enable selection and
entry of said desired temperature range into said system and to
generate control signals to control each of said at least one heat
pump, wherein said controller assembly controls each of said at
least one heat pump to heat or cool the cabinet interior as
required in response to a comparison of said temperature signal
received from said temperature sensor with said selected
temperature range to maintain said cabinet interior within said
selected temperature range; and a thermal barrier disposed between
said at least one door and a rear wall of said cabinet to impede
heat exchange between said cabinet interior and the ambient
environment and maintain temperature of said cabinet interior and
said at least one medical item contained therein when said cabinet
interior is exposed to that environment; wherein said thermal
barrier is configured to facilitate passage of said at least one
medical item through said thermal barrier and to retain heat within
said cabinet interior in response to said cabinet interior
temperature exceeding a temperature of the ambient environment and
impede heat from said ambient environment accessing said cabinet
interior in response to said cabinet interior temperature being
below said ambient environment temperature.
2. The system of claim 1, wherein said thermal barrier is disposed
adjacent at least one door.
3. The system of claim 1, wherein said thermal barrier is disposed
within said cabinet interior a selected distance from said at least
one door to partition said cabinet interior into a plurality of
thermally isolated compartments.
4. The system of claim 1 further including a support member
disposed between at least one door and said cabinet rear wall to
engage and support said thermal barrier within said cabinet
interior.
5. The system of claim 1, wherein said thermal barrier includes a
plurality of elongate strips.
6. The system of claim 5, wherein said plurality of strips are
arranged in an overlapping fashion to form said thermal
barrier.
7. The system of claim 5, wherein said plurality of strips are
arranged with each strip positioned a selected distance from a
neighboring strip to form said thermal barrier.
8. The system of claim 1 further comprising a plurality of thermal
barriers each disposed within said cabinet interior to partition
said cabinet interior into a plurality of thermally isolated
compartments.
9. A method of maintaining an interior of a cabinet within a
desired temperature range, wherein said cabinet stores at least one
medical item and includes at least one door to provide access to
said cabinet interior, a temperature sensor, a controller assembly
to control system operation, at least one heat pump to heat or cool
said cabinet interior, and a thermal barrier disposed between said
at least one door and a cabinet rear wall, said method comprising
the steps of: (a) receiving said desired temperature range for said
at least one medical item entered into said controller assembly;
(b) with said temperature sensor, measuring a temperature within
said cabinet interior and generating a temperature signal
indicating said measured cabinet interior temperature; (c) with
said controller assembly, comparing said temperature signal
received from said temperature sensor to said desired temperature
range; (d) controlling each of said at least one heat pump, via
said controller assembly, to heat or cool said cabinet interior as
required in response to said comparison of said temperature signal
with said desired temperature range to maintain said cabinet
interior temperature within said desired temperature range; (e)
with said thermal barrier, impeding heat exchange between said
cabinet interior and the ambient environment and maintaining
temperature of said cabinet interior and said at least one medical
item contained therein when said cabinet interior is exposed to
that environment by retaining heat within said cabinet interior in
response to said cabinet interior temperature exceeding a
temperature of the ambient environment and impeding heat from said
ambient environment accessing said cabinet interior in response to
said cabinet interior temperature being below said ambient
environment temperature.
10. The method of claim 9, wherein step (e) further includes: (e.1)
with said thermal barrier disposed adjacent at least one door,
impeding heat exchange between said cabinet interior and the
ambient environment and maintaining temperature of said cabinet
interior and said at least one medical item contained therein when
said cabinet interior is exposed to that environment.
11. The method of claim 9, wherein step (e) further includes: (e.1)
forming a plurality of thermally isolated compartments within said
cabinet interior by disposing said thermal barrier within said
cabinet interior a selected distance from said at least one
door.
12. The method of claim 9, wherein said cabinet further includes a
support member disposed between at least one door and said cabinet
rear wall, and step (e) further includes: (e.1) supporting said
thermal barrier within said cabinet interior via said support
member.
13. The method of claim 9, wherein said thermal barrier includes a
plurality of elongate strips, and step (e) further includes: (e.1)
forming said thermal barrier by arranging said strips in an
overlapping fashion.
14. The method of claim 9, wherein said thermal barrier includes a
plurality of elongate strips, and step (e) further includes: (e.1)
forming said thermal barrier by positioning each strip a selected
distance from a neighboring strip.
15. The method of claim 9, wherein said cabinet includes a
plurality of said thermal barriers, and step (e) further includes:
(e.1) forming a plurality of thermally isolated compartments within
said cabinet interior by disposing said thermal barriers within
said cabinet interior.
16. A method of maintaining an interior of a cabinet within a
desired temperature range via a temperature control system, wherein
said cabinet stores at least one medical item and includes at least
one door to provide access to said cabinet interior, and said
temperature control system includes a temperature sensor, a
controller assembly to control system operation, at least one heat
pump to heat or cool said cabinet interior, and a thermal barrier
disposed between said at least one door and a cabinet rear wall,
said method comprising the steps of: (a) retrofitting said
temperature control system into a pre-existing cabinet lacking
temperature control capability; (b) receiving said desired
temperature range for said at least one medical item entered into
said controller assembly; (c) measuring a temperature within said
cabinet interior via said temperature sensor disposed within said
cabinet interior; (d) controlling each of said at least one heat
pump, via said controller assembly, to heat or cool said cabinet
interior as required to maintain said cabinet interior temperature
within said desired temperature range, wherein said controller
assembly controls each of said at least one heat pump in response
to a comparison of said measured cabinet interior temperature with
said desired temperature range; (e) impeding heat exchange between
said cabinet interior and the ambient environment, via said thermal
barrier, and maintaining temperature of said cabinet interior and
said at least one medical item contained therein when said cabinet
interior is exposed to that environment.
17. A temperature controlled cabinet system for storing medical
items and maintaining said medical items within a desired
temperature range comprising: storage means to receive at least one
medical item within an interior of said storage means and including
at least one access means for providing access to said interior; at
least one thermal means partially disposed within said interior for
heating or cooling said interior; temperature means disposed within
said interior to measure an interior temperature and to generate a
temperature signal indicating said measured interior temperature;
controller means for enabling selection and entry of said desired
temperature range into said system and for generating control
signals to control each of said at least one thermal means, wherein
said controller means controls each of said at least one thermal
means to heat or cool said interior as required in response to a
comparison of said temperature signal received from said
temperature sensor with said selected temperature range to maintain
said interior within said selected temperature range; and thermal
insulation means disposed between said at least one access means
and a rear portion of said storage means for impeding heat exchange
between said interior and the ambient environment and maintaining
temperature of said interior and said at least one medical item
contained therein when said interior is exposed to that
environment; wherein said thermal insulation means facilitates
passage of said at least one medical item through said thermal
insulation means and retains heat within said interior in response
to said interior temperature exceeding a temperature of the ambient
environment and impedes heat from said ambient environment
accessing said interior in response to said interior temperature
being below said ambient environment temperature.
18. The system of claim 17, wherein said thermal insulation means
is disposed adjacent at least one access means.
19. The system of claim 17, wherein said thermal insulation means
is disposed within said interior a selected distance from said at
least one access means to partition said interior into a plurality
of thermally isolated compartments.
20. The system of claim 17 further including support means disposed
between at least one access means and said rear portion to engage
and support said thermal insulation means within said interior.
21. The system of claim 17, wherein said thermal insulation means
includes a plurality of elongate strips.
22. The system of claim 21, wherein said plurality of strips are
arranged in an overlapping fashion to form said thermal insulation
means.
23. The system of claim 21, wherein said plurality of strips are
arranged with each strip positioned a selected distance from a
neighboring strip to form said thermal insulation means.
24. The system of claim 17 further comprising a plurality of
thermal insulation means each disposed within said interior to
partition said interior into a plurality of thermally isolated
compartments.
25. The system of claim 1, wherein said thermal barrier includes at
least one opening to facilitate passage of said at least one
medical item through said thermal barrier.
26. The method of claim 9, wherein said thermal barrier includes at
least one opening, and step (e) further includes: (e.1)
facilitating passage of said at least one medical item through said
thermal barrier via said opening.
27. The system of claim 17, wherein said thermal insulation means
includes at least one opening to facilitate passage of said at
least one medical item through said thermal insulation means.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention pertains to temperature control
systems. In particular, the present invention pertains to a
temperature control system for installation within cabinets of
ambulances or other medical vehicles to maintain cabinet interiors
at appropriate temperatures for storing medical items (e.g., drugs
and/or intravenous (IV) solution). The temperature control system
employs a thermal barrier to thermally isolate a cabinet interior
and corresponding medical items contained therein from the ambient
environment during intervals where the cabinet interior is exposed
to that environment (e.g., during intervals where at least one
cabinet door is in an open state).
[0003] 2. Discussion of Related Art
[0004] Ambulances and other medical vehicles typically include
cabinets to store medical items, such as drugs or intravenous (IV)
solution, for use by medical personnel. These items are usually
required to be maintained at specific temperatures. For example, IV
solution is typically contained within IV bags and needs to be
maintained at approximately body temperature in order to avoid
thermal shock and injury to a patient. Similarly, certain drugs are
required to be maintained at particular temperatures in order to
lengthen their active life and/or be safely administered to
patients. However, typical cabinets utilized in ambulances and
other medical vehicles do not provide a temperature controlled
environment, but rather merely store medical items. Further, the
cabinets typically do not include a thermal barrier to thermally
isolate the cabinet interior from the ambient environment when
cabinet doors are in an open state. Thus, drugs or IV solutions
that are initially thermally treated to have temperatures within
their appropriate utilization temperature range may quickly attain
temperatures outside that range when stored in cabinets lacking a
thermal barrier and/or temperature control capability, thereby
risking injury to the patient.
[0005] The related art has attempted to overcome these problems by
utilizing various temperature controlled systems. For example, U.S.
Pat. No. 5,217,064 (Kellow et al) discloses a temperature
controlled pharmaceutical storage device including a substantially
enclosed and thermally insulated structure having at least one port
allowing access to an enclosed storage area. A thermopile heat
exchange unit is provided for heating and cooling the storage area
in response to signals provided by temperature sensors and a window
detector. The storage area is maintained at a temperature between
upper and lower predetermined limits, while a visual display is
actuated in response to the temperature limits being exceeded for a
predetermined length of time to warn that substances should be
discarded immediately. The storage device may be mounted in an
ambulance.
[0006] U.S. Pat. No. 5,572,873 (Lavigne et al) discloses a carrier
apparatus having an insulated structure with a drawer unit located
therein. A primary thermal electric cooler heats and cools the
pharmaceuticals located within the drawer unit, while a controller
senses the temperature within the drawer unit and operates the
thermal electric cooler to maintain the interior of the drawer unit
at room temperature. The drawer unit includes an insulated
refrigerated drawer having a thermal electric cooler operated by
the controller to hold refrigerated drugs. The apparatus provides
warnings of a temperature violation, and locks a door providing
access to the drawer unit in response to detection of the
temperature violation within drawers maintained at room
temperature.
[0007] U.S. Pat. No. 5,924,289 (Bishop, II) discloses a temperature
controlled cabinet system typically for use in ambulances and other
medical vehicles. The cabinet system includes a temperature sensor
for measuring the cabinet interior temperature, a controller
assembly for controlling system operation and preferably two heat
pumps disposed in the cabinet walls to heat or cool the cabinet
interior. A control console within the controller assembly displays
the actual cabinet temperature and facilitates entry of a desired
temperature range into the system. The control console further
displays cooling mode and heating mode indicator lights to indicate
when the cabinet interior temperature has shifted out of the
desired temperature range. The heat pumps include a pair of heat
sinks disposed about a thermoelectric device (e.g., a Peltier chip)
that heats one heat sink, while cooling the other heat sink based
upon a voltage polarity or current flow direction applied to the
device. The system controls the voltage polarity applied to the
thermoelectic device to enable the heat pumps to heat or cool the
cabinet interior based upon a comparison of the measured
temperature with the desired temperature range.
[0008] In addition, various systems of the related art have
employed thermal barriers in the form of coverings or curtains for
varying applications. For example, U.S. Pat. No. 4,288,992
(Eliason) discloses a curtain structure for substantially covering
an access opening of an open-sided, display type, refrigerated food
cabinet. A first curtain comprises a flexible sheet prestressed to
roll up and fixed at its upper edge to the ceiling of the cabinet
inboard of the access opening. The first curtain maybe unrolled and
its bottom edge attached to the floor of the cabinet to
substantially block air movement into and out of the cabinet. A
second curtain comprises a plurality of side-by-side, elongate
strips of flexible transparent sheet material, fixed together at
their upper ends and supported on the cabinet at the top of the
access opening. The lower ends of the strips are free of each other
and terminate slightly above the bottom of the access opening. The
second curtain is spaced away from the closed position of the first
curtain by an air layer providing a thermal barrier across the
access opening when access to the interior of the cabinet is not
needed. With the first curtain rolled up, the second curtain
obstructs air movement into and out of the cabinet but permits
visual and physical access to the interior of the cabinet through
the access opening.
[0009] U.S. Pat. No. 4,296,792 (Gidge et al) discloses a
transparent, flexible curtain with spaced access points for
installation over an opening of a display type open refrigerator of
the type used in retail food markets. The curtain includes a
plurality of elongated, flexible, transparent panels secured at one
end to the top or rear edge of the refrigerator cabinet and
extending in overlapped relation across the cabinet opening. The
curtain retains cold air within the refrigerator and allows food
products to be clearly visible to the customer. Goods are removed
by the customer reaching in between adjacent panels which separate
easily and return to a closed position when the customer's hand is
withdrawn.
[0010] U.S. Pat. No. 4,746,029 (Tyner III, et al) discloses a
cooler curtain for maintaining an air barrier between the opening
of a storage facility and the surrounding atmosphere. A plurality
of closely spaced, resilient self-closing curtain elements are
relatively movable between a closed position in which the elements
of a pair thereof are closely adjacent and collectively define an
air barrier to impede air movement through a portion of the
opening, and an open position in which the elements in the pair are
spaced further apart to provide access therebetween to the storage
unit through the opening. A drop-in removable insert frame
structure is suspended over the horizontal, top opening of the
storage facility to position the curtain elements over the front
opening and top opening forming the air barrier. The plurality of
self-closing curtain elements extend horizontally between the side
rails of the frame over the top opening, and depend generally
vertically from the front rail of the frame over the front opening.
The frame structure may be recessed within the storage unit to
permit closure thereof without removal of the cooler curtain. The
curtain elements are secured by a retaining member to the underside
of the frame by fastening means. In addition, the cooler curtain
may be used to maintain the interior portion of a storage unit at
significantly higher than room temperature for heating or food
warming applications.
[0011] U.S. Pat. No. 5,431,490 (Edwards) discloses a vertical
curtain having vertical slits defined therein and spaced
thereacross. The slits open downwardly through the lower margin of
the curtain and terminate upwardly a spaced distance below a
curtain upper margin. The curtain upper margin is mounted on a
margin of a refrigerated cabinet wall having an access opening
formed therein. The refrigerated cabinet margin extends across the
upper portion of the opening, while the curtain falls by gravity
downwardly across the opening as a thermal and convection current
barrier when the door for the access opening is opened.
[0012] U.S. Pat. No. 5,746,271 (DeCosta) discloses a doghouse
having a heating and air conditioning unit installed therein,
insulated walls and an insulated roof. Hinges connect the roof on
one of its sides to the upright walls for easy access by the pet
owner to the controls of the heating and air conditioning unit. The
doghouse includes a flexible door covering with laterally
overlapping parallel strips that are made from a heavy material so
as to be minimally effected by tangling and frequent wind
interaction. The strips are vertically hung from the upper part of
the door opening to allow pets freedom of access in and out of the
doghouse, while at the same time retaining the major portion of the
climate controlled air within the insulated walls and roof of the
doghouse during pet use.
[0013] The related art suffers from several disadvantages. In
particular, the Kellow et al, Lavigne et al and Bishop, II systems
may enable their system interiors and medical items (e.g., drugs,
intravenous (IV) solution, etc.) contained therein to attain
temperatures that are beyond the desired temperature range. This
tends to occur during intervals where an operator accesses medical
items stored by the systems or inadvertently leaves system doors in
an open state, thereby exposing the system interiors to the ambient
environment. Consequently, the medical items contained within the
system interiors may attain temperatures that compromise their
efficacy due to a heat exchange between the exposed system
interiors and ambient environment. This problem is exacerbated when
the temperature of the ambient environment differs significantly
from the desired temperature maintained by the systems. In response
to detection of the compromising temperatures, these systems may
provide visual indications to the operator, while the Lavigne et al
system may further prevent access to the stored medical items.
However, since these measures concentrate on notification of, or
precautionary measures subsequent to, occurrence of the
compromising temperatures, the systems are not concerned with and
do not provide a manner to prevent or minimize occurrences of that
event.
[0014] Although certain systems described above employ thermal
barriers in the form of coverings or curtains to maintain system
interiors at desired temperatures, these thermal barrier systems
suffer from several disadvantages, especially with respect to
medical applications. In particular, the thermal barrier systems
described above are configured for applications providing a
suitable environment for various items (i.e., food products and
pets) having relatively relaxed temperature requirements and
therefore are generally not suitable for handling medical
applications with rigid temperature constraints. Further, the Gidge
et al and Eliason systems employ a curtain for a display type
refrigerated cabinet containing food products. The curtain is
utilized as the primary thermal barrier for the cabinet during
extended time intervals within which consumers may access the food
products. However, this enables substantial heat exchange between
the refrigerated cabinet interior and ambient environment, thereby
causing significant temperature fluctuations within the system
interiors. With respect to medical applications, these fluctuations
may readily permit medical items (e.g., drugs, intravenous (IV)
solution, etc.) to attain temperatures that are beyond their
required temperature range and compromise medical item efficacy.
The DeCosta structure employs a covering or curtain as the primary
thermal barrier and similarly permits the above heat exchange and
temperature fluctuations within the structure interior. Further,
the Tyner, III et al system employs a frame having curtain elements
respectively covering front and top openings of a storage unit.
Thus, this system basically includes additional access openings
that facilitate enhanced heat transfer and temperature fluctuations
within the storage unit interior during use and access of that
interior.
[0015] The Edwards system employs a curtain in the form of a sheet
having slits defined therein for mounting on upright refrigerators
and freezers. However, the curtain tends to slightly obstruct
closing of refrigerator and freezer doors, thereby enabling
formation of gaps between the doors and corresponding units. These
gaps may facilitate heat transfer and temperature fluctuations
within the refrigerated interiors. Further, the curtain is
typically displaced when the refrigerator and freezer doors are in
a closed state, thereby creating deformities in the curtain over
extended time intervals that degrade the effectiveness of the
curtain as a thermal barrier.
OBJECTS AND SUMMARY OF THE INVENTION
[0016] Accordingly, it is an object of the present invention to
precisely control temperature within ambulance or other medical
vehicle cabinets to maintain medical items contained therein at
desired temperatures.
[0017] It is another object of the present invention to maintain a
desired temperature within medical vehicle cabinets during time
intervals in which at least one cabinet door is in an open state
(e.g., during loading and unloading of medical items within the
cabinet interior).
[0018] Yet another object of the present invention is to maintain a
desired temperature within a cabinet interior during time intervals
in which at least one cabinet door is in an open state by employing
a thermal barrier within the cabinet in the form of a plurality of
thermally insulated strips to thermally isolate the cabinet
interior from the ambient environment.
[0019] The aforesaid objects may be achieved individually and/or in
combination, and it is not intended that the present invention be
construed as requiring two or more of the objects to be combined
unless expressly required by the claims attached hereto.
[0020] According to the present invention, a temperature controlled
cabinet system for maintaining a cabinet or other storage structure
interior at a desired temperature includes at least one heat pump
disposed within a cabinet wall, a controller assembly for providing
a user interface and controlling system operation and a temperature
sensor for measuring cabinet interior temperature. The heat pump is
capable of heating and/or cooling the cabinet interior to maintain
the cabinet interior at the desired temperature. The system is
preferably directed toward cabinets disposed in ambulances and
other medical vehicles in order to maintain medical items, such as
drugs or intravenous solution, contained within the cabinets at
their appropriate temperatures (e.g., 21.degree. C.-26.degree. C.
for drugs, 35.degree. C.-40.degree. C. for IV solution). The
cabinet system further includes a thermal barrier disposed toward
and substantially covering the cabinet interior entrance to
thermally isolate the cabinet interior from the ambient environment
and permit access to medical items contained within the cabinet.
The thermal barrier includes a plurality of strips that may be
spaced from each other a selected distance, or be arranged in an
overlapping fashion to substantially impede or minimize heat
exchange between the cabinet interior and ambient environment
during intervals where the cabinet interior is exposed to that
environment (e.g., intervals where at least one cabinet door is in
an open state).
[0021] The above and still further objects, features and advantages
of the present invention will become apparent upon consideration of
the following detailed description of specific embodiments thereof,
particularly when taken in conjunction with the accompanying
drawings wherein like reference numerals in the various figures are
utilized to designate like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is an exploded view in perspective of an exemplary
temperature controlled cabinet system according to the present
invention.
[0023] FIG. 2 is a block diagram of an exemplary temperature
control system of the cabinet system of FIG. 1.
[0024] FIG. 3 is a front view in plan of an exemplary control
console of the temperature control system of FIG. 2.
[0025] FIG. 4A is a view in perspective of the cabinet system of
FIG. 1 having a thermal barrier disposed within the cabinet
interior according to the present invention.
[0026] FIG. 4B is a front view in elevation and partial section of
the cabinet system of FIG. 4A.
[0027] FIG. 4C is a view in section of the cabinet system thermal
barrier taken along lines 4C-4C in FIG. 4B.
[0028] FIG. 5 is a view in perspective of the cabinet system of
FIG. 1 having an alternative thermal barrier disposed within the
cabinet interior according to the present invention.
[0029] FIG. 6 is an exploded view in perspective of an alternative
embodiment of the temperature controlled cabinet system of FIG. 1
having a single heat pump according to the present invention.
[0030] FIG. 7 is a block diagram of an exemplary temperature
control system of the cabinet system of FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] An exemplary cabinet system of the present invention for use
in ambulance or other medical vehicles to contain medical items
(e.g., drugs or intravenous solution contained within IV bags) is
illustrated in FIG. 1. Specifically, the system includes a cabinet
18, a temperature control system 40 (FIG. 2), a support member 110
(FIG. 4B) and a thermal barrier 80 (FIG. 4B). Cabinet 18, typically
disposed along with a plurality of other cabinets within an
ambulance or other medical vehicle interior, is similar in shape to
a substantially rectangular box and includes top and bottom walls
20, 22, side walls 24, 26 and rear wall 30. The cabinet front
typically includes doors 32,34, preferably disposed between top and
bottom walls 20,22 and side walls 24,26. Each cabinet wall is
substantially rectangular with top and bottom walls 20, 22 having
substantially similar dimensions. Side walls 24, 26 have dimensions
substantially similar to each other, while rear wall 30 is disposed
between top and bottom walls 20, 22 and side walls 24, 26 such that
the cabinet walls and doors collectively define a cabinet interior.
It is to be understood that the terms "front", "rear", "top",
"bottom", "side", "lower", "upper", "vertical", "horizontal",
"width", "length" and the like are used herein merely to describe
points of reference and do not limit the present invention to any
specific configuration or orientation. Thermally insulating doors
32,34 are typically disposed at the front of the cabinet to enable
placement and removal of medical items, such as drugs or
intravenous solution bags, within the cabinet interior. By way of
example only, cabinet 18 includes two substantially rectangular
sliding doors 32,34, however, the cabinet may include any quantity
or type of doors at any location that open and close in any manner
or direction. Further, the cabinet doors may be of any shape, while
the cabinet interior may include any quantity of shelves to contain
the medical items.
[0032] Doors 32, 34 are each typically substantially rectangular
having substantially similar dimensions wherein the height of each
door is slightly less than the distance between top wall 20 and
bottom wall 22, while the width of each door is approximately
one-half the width of the cabinet. Doors 32, 34 are typically
disposed one in front of the other to permit the doors to slide
between the cabinet side walls and enable access to the cabinet
interior. By way of example only, door 34 is disposed in front of
door 32 such that door 32 is slightly recessed toward the cabinet
interior, while door 34 is substantially flush with the top, bottom
and side wall edges. However, the doors may be disposed on the
cabinet in any manner capable of permitting the doors to slide
between the side walls. Alternatively, doors 32, 34 may be attached
to cabinet 18 via hinges such that the doors may pivot to an open
or closed position. Doors 32, 34 are typically secured to cabinet
18 via rails or tracks (not shown) disposed on the interior surface
of top wall 20 and/or bottom wall 22. The doors engage the tracks
to slide between the cabinet side walls. Doors 32, 34 each include
a knob or handle 38 disposed toward the middle portion of each door
32, 34 adjacent a vertical door edge closest to respective cabinet
side walls 24, 26. Knobs 38 may be any conventional knobs, handles
or recesses within the doors and may be disposed anywhere on the
doors in any fashion. For example, knobs 38 maybe implemented by a
handle having a substantially circular gripping portion attached to
an elongated stem (e.g., as illustrated in FIG. 1) that provides
sufficient distance between the gripping portion and the cabinet to
enable an operator hand to manipulate the door.
[0033] Heat pumps 54 are typically placed within cabinet side wall
24 via openings 85. By way of example only, two heat pumps are
utilized in the exemplary cabinet system, however, the cabinet
system may include any quantity of heat pumps, or any other type of
thermal device placed at any location on the cabinet to maintain
the cabinet interior at a desired temperature. Heat pumps 54 may be
implemented by any conventional heat pumps or thermoelectric
devices. By way of example only, the heat pumps each include an
exterior heat sink 88 with corresponding axial fan 90, an interior
heat sink 92 with corresponding axial fan 94, and an insulating
layer 95 and a Peltier chip 96 (e.g., thermoelectric device)
disposed between the exterior and interior heat sinks. Exterior
heat sink 88 typically has larger dimensions than interior heat
sink 92. Heat pumps 54 are inserted into cabinet wall 24 via
openings 85 with insulation 95 and Peltier chip 96 substantially
coincident the wall, exterior heat sink 88 disposed exterior of the
cabinet and interior heat sink 92 disposed within the cabinet
interior.
[0034] Heat sinks 88 and 92 are substantially rectangular and are
typically constructed of a thermally conductive material (e.g.,
metal). Fans 90 and 94 circulate air through channels or passages
(not shown) defined in the heat sinks and back to the corresponding
surrounding area. In particular, air within the cabinet interior
traverses interior heat sink 92 and returns to the cabinet interior
via fan 94. The circulating air transfers thermal energy from the
interior heat sink to the cabinet interior to heat or cool the
cabinet interior and maintain a desired temperature. The air
circulation for exterior heat sink 88 is substantially similar to
that of heat sink 92 described above, except that the air is
circulated with respect to the surrounding environment (e.g.,
external of the cabinet).
[0035] Heat pumps 54 utilize Peltier chip 96 (i.e., a solid state
thermoelectric device) to heat and cool heat sinks 88 and 92. This
type of thermoelectric device typically includes an array of
thermocouples that operate in accordance with the Peltier effect.
Basically, the thermoelectric device obeys the laws of
thermodynamics in a similar manner as mechanical heat pumps,
refrigerators or other devices used to transfer heat energy, except
that this device includes solid state electrical components instead
of mechanical/fluid heating and cooling components. Specifically,
when D.C. (i.e., direct current) electrical power is applied to a
thermoelectric device having an array of thermocouples, heat is
absorbed on a cold side of the thermocouples wherein the heat
passes through the thermocouples to be dissipated on the hot side
of the thermocouples. Heat sinks are typically disposed on the hot
and cold sides of the thermocouples to respectively aid in
dissipating heat to, or removing heat from, the adjacent
environment. Whether the heat sinks absorb or dissipate heat is
determined by the direction of current flow through, or voltage
polarity applied to, the device in accordance with the Peltier
effect.
[0036] Peltier chip 96 enables heat sinks 88 and 92 to dissipate
and absorb heat based on the voltage polarity applied to that chip.
In particular, the Peltier effect stipulates that when current
passes across a junction between two different metals, heat is
either absorbed or dissipated based on current flow in relation to
junction voltage direction. Current opposing the voltage direction
causes heating of the junction, while current flowing with the
voltage causes junction cooling. For example, an electric current
driven in a bimetallic circuit maintained at uniform temperature
causes heat to be dissipated at one circuit junction and absorbed
at the other junction. This phenomenon occurs since an isothermal
electric current in a metal is accompanied by a thermal current.
Since the electric current is uniform and the thermal currents vary
between metals, the difference in thermal currents is dissipated at
one junction and absorbed at the other junction to maintain uniform
temperature. In other words, it is necessary to supply heat at one
junction and extract heat at the other junction to maintain uniform
temperature in a bimetallic circuit. Peltier chip 96 functions in a
similar manner to dissipate heat to interior heat sink 92, while
absorbing heat (i.e., cooling) from exterior heat sink 88 based on
the direction of current flow or voltage polarity received by the
chip. When the current flow or voltage polarity is reversed, then
heat is dissipated to exterior heat sink 88 and absorbed from
interior heat sink 92. For further examples of thermoelectric
devices and their operation, reference is made to U.S. Pat. No.
5,315,830, incorporated herein by reference in its entirety.
[0037] An exemplary temperature control system for maintaining the
cabinet interior at a specified temperature in order to accommodate
medical items requiring certain storage temperature ranges is
illustrated diagrammatically in FIG. 2. Specifically, temperature
control system 40 includes a controller assembly 42, a temperature
sensor 44 interfacing a sensor plug type connector 37, a controller
wiring harness 49 including receptacle type connectors 46 and 47, a
heat pump wiring harness 48 including plug type connector 50 and
receptacle type connectors 52, and heat pumps 54. The controller
assembly includes a control console (FIG. 3) having a controller
display that provides an indication of the temperature within the
cabinet interior, while input devices disposed below the display
enable programming of the controller 14 assembly and entry of a
desired cabinet temperature as described below. Heat pumps 54 are
typically installed within cabinet side walls as described above to
heat and/or cool the cabinet interior based on control signals
generated by controller assembly 42. The heat pumps are each
connected to a respective connector 52 of heat pump harness 48 via
a plug type connector 98 wherein connectors 52 are connected to
receptacle 47 of controller harness 49, via connector 50, to
receive signals from controller assembly 42. Receptacle 47 of
controller harness 49 is connected to controller assembly 42 and
conveys control signals to receptacle connectors 52, via plug
connector 50, to control heat pumps 54. Temperature sensor 44,
typically an RTD thermocouple, is disposed within the cabinet
interior to measure cabinet interior temperature and to send a
converted signal representing the temperature to the controller
assembly. Temperature sensor 44 is connected to receptacle
connector 46 of controller harness 49 via plug connector 37 wherein
the controller harness interfaces the controller assembly to convey
the temperature signals representing the cabinet interior
temperature to the controller assembly.
[0038] Controller assembly 42 includes a control console described
below having switches and a display for entering a desired
temperature and displaying the current temperature of the cabinet
interior. The controller assembly generates signals in a manner
described below to control heat pumps 54 in response to a
particular reading from sensor 44. In other words, when the cabinet
interior temperature exceeds a desired temperature, controller
assembly 42 directs heat pumps 54 to cool the interior, while
directing heat pumps 54 to heat the cabinet interior when the
cabinet interior temperature is less than a desired temperature.
Temperature control system 40 may be incorporated into new cabinets
during manufacture, or may be retrofit into cabinets lacking
temperature control capability to form a temperature controlled
cabinet. For examples of the structure and operation of the heat
pumps and this type of control system, reference is made to U.S.
Pat. No. 5,924,289 (Bishop, II), the disclosure of which is
incorporated herein by reference in its entirety. The cabinet
system typically includes a preset temperature range of 21.degree.
C.-26.degree. C. or 35.degree. C.-40.degree. C., however, any
temperature or range may be programmed or entered into the system
to maintain the cabinet interior at a suitable temperature for
storing various medical or other items.
[0039] Controller assembly 42 controls system operation and
includes a faceplate or control console 56 as illustrated, by way
of example only, in FIG. 3. Specifically, control console 56 is
substantially rectangular and includes a power (i.e., ON/OFF)
switch 58, fuse holder 61, preferably including a fifteen amp fuse
62, and a controller display 63. Fuse holder 61 is generally
disposed between power switch 58 and controller display 63 toward
an upper portion of control console 56, however, the control
console may be of any shape with the power switch, fuse holder and
display arranged on the control console in any fashion. Power
switch 58 may be implemented by any conventional power switch, and
by way of example only, is implemented by a substantially
rectangular switch wherein depressing an end of the switch
associated with "ON" or "OFF" attains the desired power
distribution to the system. Fuse holder 61 may be implemented by
any conventional fuse holder and is preferably implemented by a
panel mount fuse holder typically suited to contain a fifteen amp
fuse. Controller display 63 includes a light emitting diode (LED)
or liquid crystal (LCD) temperature display 66 for displaying the
temperature of the cabinet interior. Controller display 63 is
generally configured to display four digits, however, the display
may be implemented to display any number of digits. The controller
assembly is typically programmable and provides the appropriate
signals to the heat pumps to maintain the cabinet interior at the
desired temperature.
[0040] Controller display 63 may further include cooling mode and
heating mode indicator lights 68, 69, preferably disposed
diagonally opposite each other to indicate when the interior
cabinet temperature has shifted out of a desired temperature range.
In particular, cooling mode indicator light 68 is disposed toward
the bottom portion of temperature display 66 and indicates a
cabinet interior temperature above the desired temperature range,
while heating mode indicator light 69 is disposed toward the top
portion of temperature display 66 and indicates a cabinet interior
temperature below the desired temperature range. User interface
buttons 70, 72 and 74 are disposed below temperature display 66 and
enable programming of the controller assembly and entry of a
desired cabinet temperature. Buttons 70, 72 and 74 are labeled with
various indicia (e.g., a star, down arrow and up arrow) to
distinguish the buttons and indicate button functions. Generally,
button 70 labeled with a star is used for selection, while buttons
72 and 74 are used for manipulating data to be entered. The buttons
may be arranged in any manner on controller display 63 and may
include any indicia uniquely identifying each button. The control
console is typically constructed of metal and may be disposed
within an ambulance or other medical vehicle at any suitable
location. The control console may alternatively be constructed of
any other sufficiently sturdy material.
[0041] The controller assembly circuitry is generally mounted on
the back of the control console and includes power switch 58, fuse
holder 61 with fuse 62 as described above, a programmable
controller and switching circuitry. The controller maybe
implemented by any conventional or other programmable controller,
and receives commands from an operator via buttons 70, 72, 74 as
described above. The switching circuitry controls the heat pumps in
accordance with the controller to maintain the cabinet interior at
the desired temperature. For an example of the structure and
operation of controller assembly circuitry, reference is made to
above-mentioned U.S. Pat. No. 5,924,289 (Bishop, II).
[0042] Doors 32, 34 of cabinet 18 thermally isolate the cabinet
interior from the ambient environment in response to the doors
being in a closed state. However, when at least one of the cabinet
doors is in an open state, the cabinet interior is exposed to and
in thermal exchange relation with the ambient environment, thereby
adversely affecting the cabinet interior temperature. Accordingly,
the cabinet system of the present invention further includes a
thermal barrier to thermally isolate the cabinet interior from the
ambient environment (e.g., minimize or significantly impede the
thermal exchange between the cabinet interior and ambient
environment) and maintain the desired cabinet interior temperature
in response to exposure of the cabinet interior to that environment
(e.g., an open state of at least one cabinet door). An exemplary
cabinet system thermal barrier is illustrated in FIGS. 4A-4C.
Specifically, cabinet 18 is substantially similar to the cabinet
described above and includes heat pumps 54 disposed in side wall 24
to control the cabinet interior temperature. The heat pumps are
preferably horizontally aligned within an upper portion of side
wall 24, but may be disposed at any suitable locations within any
cabinet walls. The cabinet further includes thermal barrier 80 and
support member 110 to suspend the thermal barrier within the
cabinet interior. An optional shelf 36 may be removably or
otherwise attached to side walls 24, 26 at intermediate sections
thereof. The shelf is typically substantially rectangular and
basically partitions the cabinet interior into upper and lower
compartments 82, 84 each for containing medical items 120 placed
therein. The cabinet side walls each preferably include a groove or
slot (not shown) for receiving shelf side edges, however, any
suitable technique for supporting the shelf within the cabinet
interior may be employed. The shelf extends for a distance slightly
less than the distance between thermal barrier 80 and the cabinet
rear wall to form passages for air flow between the upper and lower
compartments. The passages enable heat pumps 54 to circulate
thermally treated air between the upper and lower compartments for
maintaining the cabinet interior at a desired temperature.
Alternatively, each heat pump may be disposed in a cabinet wall
coincident a corresponding compartment to thermally treat that
compartment in substantially the same manner described above.
[0043] Support member 110 is recessed inwardly a slight distance
from the cabinet interior entrance or side wall front edges and is
preferably attached to and extends between upper sections of
cabinet side walls 24,26. The support member may be attached to the
cabinet side and/or top walls via any suitable fastening mechanisms
(e.g., brackets, bolts, etc.) and typically includes clasps or
other fastening devices (not shown) to engage and suspend thermal
barrier 80 within the cabinet interior. The support member may be
of any shape or size, and may be constructed of any suitable
materials.
[0044] Thermal barrier 80, by way of example only, includes a
plurality of flexible insulating strips 100a-100f each having a
substantially rectangular configuration. The strips are preferably
constructed of a substantially transparent plastic material, while
the longer dimension of each strip extends from support member 110
toward the cabinet bottom wall. The longer dimension or length of
each strip is slightly less than the distance between the cabinet
top and bottom walls, while the strip shorter dimension or width is
substantially less than the cabinet width. However, the thermal
barrier may include any quantity of strips of any shape or size and
constructed of any suitable materials to thermally isolate the
cabinet interior from the ambient environment. The strips are
arranged to successively extend in a transverse direction across
the cabinet interior entrance with the longer dimension edges of
neighboring strips adjacent each other. A slot or opening (not
shown) maybe defined toward the top edge of each strip to
facilitate engagement of that strip by a corresponding support
member clasp, thereby attaching the strip to the support
member.
[0045] The thermal barrier strips are preferably arranged in an
overlapping fashion and are manipulable relative to each other to
facilitate passage of medical items 120 through the thermal barrier
for placement and removal within the cabinet interior. By way of
example only, strips 100b, 100d and 100f are recessed within the
cabinet interior relative to strips 100a, 100c, 100e, and are
partially covered by each of their neighboring strips. In other
words, strip 100a partially covers strip 100b; strip 100c partially
covers strips 100b and 100d; and strip 100e partially covers strips
100d and 100f (e.g., as shown in FIG. 4C). This arrangement
prevents formation of gaps between adjacent strips and provides a
thermal barrier toward the cabinet interior entrance that impedes
heat exchange between that interior and the ambient environment,
while permitting passage of medical items therethrough for
placement and removal of those items within the cabinet interior as
described above.
[0046] Thermal barrier 80 maybe disposed at any desired location
within the cabinet interior. For example, the thermal barrier may
be located adjacent the cabinet interior entrance to thermally
isolate the cabinet interior from the ambient environment as
described above. Alternatively, the thermal barrier maybe recessed
inwardly from the cabinet interior entrance to partition the
cabinet interior into a plurality of thermally isolated
compartments. Additional heat pumps may be utilized to heat and/or
cool each partitioned compartment within the cabinet interior in
substantially the same manner described above. Further, the
recessed thermal barrier may serve to insulate a compartment
defined between the thermal barrier and the cabinet rear wall
during intervals in which the cabinet interior is exposed to the
ambient environment (e.g., intervals in which at least one cabinet
door is in an open state). In effect, the cabinet interior section
located adjacent the cabinet interior entrance (e.g., the section
defined between the entrance and recessed thermal barrier)
decreases the temperature differential between the compartment and
ambient environment, thereby enhancing thermal barrier capability
to maintain the compartment at desired temperatures for medical
items contained therein when the cabinet interior is exposed to the
ambient environment (e.g., when at least one cabinet door is in an
open state).
[0047] The thermal barrier strips may be disposed within the
cabinet interior in any desired arrangement (e.g., overlapping,
non-overlapping, etc.) and at any suitable locations via any
conventional or other fastening or suspension mechanisms. Moreover,
the strips may be attached directly to the cabinet walls, or to any
type of support structure mounted on or within the cabinet. In
addition, the thermal barrier and corresponding supporting
mechanisms may be installed in new cabinet structures or
retrofitted into existing structures with or without temperature
control capability in substantially the same manner described above
to impede heat exchange between the cabinet interior and ambient
environment.
[0048] An alternative embodiment of the thermal barrier for the
cabinet system is illustrated in FIG. 5. Specifically, cabinet 18
is substantially similar to the cabinet described above for FIGS. 1
and 4A and includes a thermal barrier 200. The thermal barrier is
in the form of a generally rectangular sheet that substantially
covers the cabinet interior entrance. The sheet is preferably
constructed of the transparent material described above for thermal
barrier 80 to allow medical items disposed within the cabinet to be
visible, however, the sheet may be of any shape or size and may be
constructed of any suitable materials. Thermal barrier 200 is
typically attached to the cabinet interior top, bottom and side
walls via any conventional or other fastening mechanisms (e.g.,
screws, adhesives, clasps, etc.) and includes an opening or slit
202 that extends a substantial distance between the cabinet top and
bottom walls. The slit may be placed in a closed state to thermally
insulate the cabinet interior, and may further be opened and
expanded to permit items to pass therethrough during loading and
unloading of the cabinet. The slit may alternatively be of any
quantity, shape or size, may extend in any desired direction along
the sheet for any desired distance, and may be of any suitable
configuration to permit passage of items therethrough while
effectively thermally insulating the cabinet interior from the
ambient environment. The cabinet may include a shelf as described
above for FIG. 4B, while the sheet maybe disposed and employed
within the cabinet in substantially the same manners described
above for thermal barrier 80 (e.g., partition the cabinet interior
into compartments, dispose the sheet at any suitable locations
within the cabinet interior for additional thermal insulation,
etc.).
[0049] Operation of the cabinet system is described with reference
to FIGS. 1-3 and 4A-4C. Initially, power to the system is initiated
by actuating power switch 58 on control console 56. Fans 91, 94 are
initiated with temperature display 66 showing the cabinet interior
temperature measured by temperature sensor 44 with indicator lights
68, 69 disabled. Doors 32, 34 may be opened via knobs 38 to allow
access to the cabinet interior for placing medical items therein.
Flexible strips 100a-100f are selectively displaced from each other
by an operator to provide an opening within thermal barrier 80 for
placement of medical items within the cabinet interior. The
controller assembly is subsequently programmed to a desired
temperature in accordance with the particular medical items placed
within the cabinet interior. For example, the controller assembly
is typically programmed to a set point of 21.degree. C. for drug
storage. Alternatively, the controller may be programmed to a set
point of 35.degree. C. for IV solution storage. Each set point may
be programmed via buttons 70, 72, 74. During normal or standby mode
when the cabinet temperature resides within the desired range,
temperature display 66 indicates the actual cabinet temperature
measured by temperature sensor 44, while fans 90, 94 circulate air
through the respective heat sinks 88, 92 as described above.
[0050] In response to the measured cabinet interior temperature
exceeding the desired temperature range, cooling mode indicator
light 68 in the lower portion of the controller display flashes.
Controller assembly 42 provides signals to thermoelectric device 96
to enable interior heat sinks 92 to cool the cabinet interior as
described above. Conversely, when the measured cabinet interior
temperature falls below the desired temperature range, heating mode
indicator light 69 disposed in the upper portion of the controller
display flashes. Controller assembly 42 provides signals to
thermoelectric device 96 to enable heat transfer from exterior heat
sinks 88 to interior heat sinks 92 to heat the cabinet interior.
This process continues as described above to maintain the cabinet
interior temperature within the desired temperature range. The
medical items may be removed from the cabinet interior through the
thermal barrier for administration to patients. In effect, the
thermal barrier thermally isolates the cabinet interior from the
ambient environment, thereby permitting doors 32, 34 to remain in
an open state for extended time intervals with decreased risk of
the cabinet interior attaining temperatures outside the desired
temperature range.
[0051] Alternatively, temperature control system 40 maybe
implemented using a single large heat pump 55 in substantially the
same manner described above as illustrated in FIGS. 6-7.
Specifically, system 40 includes heat pump 55, and controller
assembly 42, temperature sensor 44, and controller wiring harness
49 each as described above. The temperature sensor is connected to
the controller assembly via controller wiring harness 49 in
substantially the same manner described above for the dual heat
pump system, while heat pump 55 is directly connected to the
controller assembly via the controller harness (e.g., since the
heat pump harness is not required). The single heat pump system is
substantially similar to, and functions in substantially the same
manner as, the dual heat pump system described above, except that a
single heat pump is utilized to maintain the cabinet interior at
the desired temperature.
[0052] Heat pump 55 includes a configuration similar to that
described above in FIG. 1 for heat pumps 54. In particular, heat
pump 55 includes insulation layer 95 and Peltier chip 96 each
disposed between interior and exterior heat sinks 77,79 wherein
fans 64,65 are disposed adjacent the respective heat sinks. The
heat sinks of pump 55 are substantially similar to but have larger
dimensions than the respective heat sinks of heat pumps 54 wherein
interior heat sink 77 of heat pump 55 corresponds to exterior heat
sink 88 of heat pump 54 and is disposed within the cabinet
interior, while exterior heat sink 79 of heat pump 55 corresponds
to interior heat sink 92 of heat pump 54 and is disposed on the
cabinet exterior. In other words, the alternative embodiment
includes an interior heat sink that has larger dimensions than
exterior heat sink 88 of heat pump 54 (e.g., the heat sinks of heat
pump 54 are basically switched in the alternative embodiment).
[0053] Installation of system 40 with a single heat pump 55 within
cabinet 18 is described. Specifically, system 40 and heat pump 55
are installed in cabinet side wall 26 in substantially the same
manner described above for the system having heat pumps 54, except
that the large interior heat sink is disposed within the cabinet
interior, while the small exterior heat sink is disposed on the
cabinet exterior. An opening 81 for heat pump 55 is defined in side
wall 26 in order to accommodate the heat pump. Once heat pump 55 is
installed within the cabinet side wall, the heat pump is connected
to harness 49 via receptacle 47, while temperature sensor 44 is
connected to receptacle 46. This is substantially similar to the
connections described above for the dual heat pump system, except
that plug 98 from heat pump 55 is directly connected to receptacle
47 since the heat pump harness is not required when utilizing a
single heat pump. Controller harness 49 is also connected to the
controller assembly. Once the heat pump is installed, the
controller assembly is installed at a suitable location within the
vehicle as described above. Subsequent to installation, the system
is operated in substantially the same manner described above, while
a thermal barrier may thermally isolate the cabinet interior from
the ambient environment when the cabinet interior is exposed to
that environment (e.g., when at least one cabinet door is in an
open state) as described above.
[0054] It will be appreciated that the embodiments described above
and illustrated in the drawings represent only a few of the many
ways of implementing a temperature controlled cabinet system and
method employing a thermal barrier to thermally isolate the cabinet
interior from the ambient environment.
[0055] The cabinet may be any type of enclosed structure,
preferably utilized in ambulances or other medical vehicles, and
may include any quantity of drawers, shelves or other storage
arrangements of any shape or size, wherein cabinets having shelves
may include any quantity of doors opening in any direction. The
cabinet may be of any shape or size, and may be constructed of any
suitable materials. The cabinet may be installed within vehicles or
stationary structures (e.g., medical facility, etc.), and may
contain any quantity of any types of medical or other items. The
cabinet may include any quantity of doors or other access devices
that may be of any shape or size, may be constructed of any
suitable materials and may be manipulable in any suitable direction
to provide access to the cabinet interior. The doors may each
include any quantity of any type of handle disposed at any suitable
locations for manipulation of that door. The doors may be attached
and manipulable relative to the cabinet via any conventional or
other fastening devices (e.g., tracks, hinges, etc.), and may
further be substantially transparent or include a window of any
shape or size disposed at any suitable locations to enable viewing
of medical or other items placed within the cabinet.
[0056] The cabinet may include any quantity of heat pumps and
temperature sensors, and may be partitioned into any quantity of
compartments that may be individually controlled (e.g., each
compartment may be associated with a heat pump and temperature
sensor). The heat pumps may be installed at any location on the
cabinet capable of heating and cooling the cabinet interior.
Similarly, the controller assembly and/or console may be installed
at any appropriate location on the cabinet and/or within the
vehicle or stationary structure capable of operating the system.
Further, any quantity of heat pumps, temperature sensors or other
devices may be utilized. The heat pumps may be installed within the
cabinet at any orientation to provide enhanced air flow. The heat
pumps may be implemented by any quantity of any conventional or
other heat pump type devices. The heat sinks may be implemented by
any sufficiently thermally conductive material and may be of any
quantity, shape or size. The heat sinks may be disposed within the
heat pump at any orientation to enhance air flow and heat pump
efficiency. The heat pump and controller wiring harness may utilize
any wiring capable of conveying signals, while the plug and
receptacle type connectors may be implemented by any quantity of
any type of conventional or other connectors capable of
establishing connections. The cabinet system may alternatively
facilitate connections directly with wires or other medium without
the use of wiring harnesses.
[0057] The Peltier chip may be implemented by any circuitry or
other thermoelectric or electromechanical devices having
thermodynamic characteristics capable of transferring thermal
energy between the heat sinks. The insulation layer may include any
conventional insulation, such as foam. The fans may be implemented
by any quantity of any conventional fans or other devices of any
shape or size and capable of circulating air. The temperature
sensor maybe implemented by an RTD thermocouple or any other
temperature sensor capable of providing temperature signals to the
controller.
[0058] The control console may include any quantity of conventional
switches or buttons for the power switch, and may include any
quantity of any conventional or other type of fuse holder and fuse
to protect the controller assembly circuitry. The temperature
display may be an LED or LCD display, or any other mechanism for
indicating temperature and the system mode. The indicator lights,
display and console may be of any color, shape or size. The console
components may be arranged and/or disposed on the console in any
fashion, while the console may be constructed of metal or other
suitable sturdy material. The controller display may be disposed at
any suitable location on the console. The temperature display may
display any desired information and include any quantity of digits.
The controller display may include any quantity of indicator lights
of any shape, size or color and disposed at any suitable locations
on the display. Further, the controller display may include any
quantity of any type of buttons or data entry devices to program
the controller in any manner for a desired temperature.
[0059] The controller may be implemented by any quantity of
conventional controllers, microprocessors or any other analog or
digital circuitry capable of processing a temperature signal from
any quantity of temperature sensors and generating control signals
for any quantity of heat pumps. The controller may be programmed to
maintain the cabinet interior and/or any quantity of thermally
isolated compartments at any corresponding desired temperature, or
within any corresponding desired temperature range. The switching
circuitry may include any quantity of any type of conventional or
other solid state switches (e.g., transistors, etc.) and relays or
other circuitry or components that are capable of supplying control
signals to any quantity of heat pumps. The components may be
arranged in any fashion to provide the proper signals to the heat
pumps. The controller assembly may alternatively include any
quantity of controllers to control any quantity of corresponding
heat pumps.
[0060] The strip thermal barrier may include any quantity of strips
of any size or shape and constructed of any suitable materials. The
strip thermal barrier may be fastened to the support member and/or
directly to any of the cabinet walls or shelves via any quantity of
any conventional or other fastening devices (e.g., clasps, hooks,
etc.). The strips may each include any quantity of slots, openings
or corresponding fastening devices for engagement with the support
member and/or cabinet walls or shelves. The support member may be
of any quantity, shape or size, and maybe constructed of any
suitable materials. The support member maybe disposed at any
locations internal or external of the cabinet, and may be attached
to any cabinet walls or shelves via any conventional or other
fastening devices (e.g., brackets, bolts, etc.). The strips may be
constructed of any suitable transparent, translucent or opaque
materials, and may be arranged in any fashion (e.g., separated by
any desired distance, overlapped in any desired fashion, etc.). The
strips maybe manipulable relative to each other and/or the cabinet
in any fashion to permit passage of items therethrough for
placement and removal within the cabinet interior. Alternatively,
the support member may include a mechanism to pivot, shift or
rotate the strips (e.g., similar to mechanisms for manipulating
vertical or other blinds) to provide passages between or through
the strips for access to the cabinet interior.
[0061] Any quantity of thermal barriers and/or shelves may be
disposed within the cabinet interior to partition that interior
into thermally isolated compartments. The compartments may receive
thermally treated air from the cabinet heat pumps, or each
compartment may be associated with any quantity of corresponding
heat pumps and temperature sensors for individual temperature
control of those compartments by a controller as described
above.
[0062] The thermal barriers may be implemented by any thermal
barrier capable of impeding transfer of heat between the cabinet
interior and the external environment surrounding the cabinet
system. The thermal barriers may permit medical or other items to
pass therethrough in any manner (e.g., by passing through or around
the barrier). The slit thermal barrier may include any quantity of
openings or slits having any orientation and configuration that
permits passage of items through the barrier. The sheet may be of
any shape or size and may be constructed of any suitable materials.
The slit thermal barrier may be attached to the cabinet interior at
any desired locations via any conventional or other fastening
mechanisms (e.g., screws, adhesives, clasps, etc.). The slit may be
of any quantity, shape or size, may extend in any desired direction
along the sheet for any desired distance, and may be of any
suitable configuration to permit passage of items therethrough.
[0063] The thermal barriers may be disposed adjacent a cabinet
interior entrance, or recessed inwardly therefrom at any selected
distance to partition the cabinet interior into at least two
thermally isolated compartments. The cabinet system of the present
invention may include any quantity or combination of any types of
thermal barriers within the cabinet interior, where the thermal
barriers maybe disposed adjacent each other or at separate
locations within the cabinet interior. For example, two thermal
barriers may be placed within the cabinet interior to separate the
interior into two or more thermally isolated compartments. The
thermal barriers may be affixed externally of the cabinet system,
where the thermal barriers may be attached to the external surface
of any of the cabinet front or other edges to cover the cabinet
interior entrance.
[0064] The cabinet system of the present invention may be
implemented in new vehicle or other cabinets as an option, or
mounted in existing cabinets lacking temperature control and
thermal barrier capability. The system may be factory set to
various temperatures, however, any temperature may be programmed
into the system as described above.
[0065] It is to be understood that the temperature controlled
cabinet system of the present invention may utilize any types of
cabinets, heating and cooling devices, appropriate controllers and
associated circuitry, and thermal barriers to control temperature
of and thermally isolate medical items contained within a cabinet
interior.
[0066] From the foregoing description it will be appreciated that
the invention makes available a novel temperature controlled
cabinet system and method employing a thermal barrier to thermally
isolate the cabinet interior from the ambient environment wherein a
cabinet system containing medical items and employing temperature
control to maintain those items at a desired temperature further
includes a thermal barrier to impede heat transfer between the
cabinet interior and ambient environment during intervals where the
cabinet interior is exposed to that environment.
[0067] Having described preferred embodiments of a temperature
controlled cabinet system and method employing a thermal barrier to
thermally isolate the cabinet interior from the ambient
environment, it is believed that other modifications, variations
and changes will be suggested to those skilled in the art in view
of the teachings set forth herein. It is therefore to be understood
that all such variations, modifications and changes are believed to
fall within the scope of the present invention as defined by the
appended claims.
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