U.S. patent application number 09/876100 was filed with the patent office on 2002-12-12 for thermoelectric temperature controlled drawer assembly.
This patent application is currently assigned to Maytag Corporation. Invention is credited to Anderson, Ronald K., Mandel, Sheldon W., Zimmerman, Robert C..
Application Number | 20020184895 09/876100 |
Document ID | / |
Family ID | 25367002 |
Filed Date | 2002-12-12 |
United States Patent
Application |
20020184895 |
Kind Code |
A1 |
Anderson, Ronald K. ; et
al. |
December 12, 2002 |
THERMOELECTRIC TEMPERATURE CONTROLLED DRAWER ASSEMBLY
Abstract
A temperature controlled drawer assembly incorporates a
thermoelectric device and a control system to selectively heat or
cool the contents of a drawer which is selectively movable into and
out of a cabinet designed to be part of an end table, such as a
nightstand, or other cabinet remote from a household kitchen. In a
cooling mode of operation, a fan, disposed in the cabinet, draws
air from inside the drawer and blows the air over a cold side of a
heat sink to cool the air. The treated air is blown through
plenums, back into the drawer. At the same time, heat is drawn away
from the cold side and directed out of the cabinet. The current
through the heat sink may be reversed to flip the cold and hot
sides of the heat sink to enable the contents of the drawer to be
heated.
Inventors: |
Anderson, Ronald K.;
(Galesburg, IL) ; Mandel, Sheldon W.; (East
Galesburg, IL) ; Zimmerman, Robert C.; (Galesburg,
IL) |
Correspondence
Address: |
DIEDERIKS & WHITELAW, PLC
12471 Dillingham Square, #301
Woodbridge
VA
22192
US
|
Assignee: |
Maytag Corporation
|
Family ID: |
25367002 |
Appl. No.: |
09/876100 |
Filed: |
June 8, 2001 |
Current U.S.
Class: |
62/3.6 ;
62/258 |
Current CPC
Class: |
F25B 2700/2104 20130101;
F25B 2321/0211 20130101; F25D 25/025 20130101; F25B 21/04
20130101 |
Class at
Publication: |
62/3.6 ;
62/258 |
International
Class: |
F25B 021/02; F25D
023/12 |
Claims
We claim:
1. A temperature controlled drawer assembly comprising: a cabinet
having at least top, front and side walls, said cabinet defining an
interior drawer space; a drawer selectively slidable into and out
of said drawer space, said drawer including a back wall, opposing
side walls, a bottom wall and a front wall; a thermoelectric
temperature adjusting device mounted inside said cabinet; a power
source connected to said temperature adjusting device; a fan,
disposed adjacent to said temperature adjusting device, said fan
being adapted to generate a flow of air across said temperature
adjusting device; and a plenum defined inside said cabinet and
extending from adjacent the fan to along a portion of the drawer,
said plenum being formed with at least one outlet opening into the
drawer space at a position remote from the fan, said plenum being
adapted to receive the flow of air generated by the fan and to
direct the flow of air into the drawer space through the at least
one outlet.
2. The temperature controlled drawer assembly according to claim 1,
further comprising: a control unit for regulating a temperature
within the drawer space.
3. The temperature controlled drawer assembly according to claim 2,
further comprising: a thermistor thermally exposed to said drawer
space, said thermistor being electrically linked to the control
unit for signaling a current temperature within the drawer
space.
4. The temperature controlled drawer assembly according to claim 1,
wherein said plenum extends along at least one of said side walls
of said cabinet.
5. The temperature controlled drawer assembly according to claim 4,
wherein said plenum includes a vent portion which defines the at
least one outlet, said vent portion being flush with said at least
one of said side walls of said cabinet.
6. The temperature controlled drawer assembly according to claim 4,
wherein said plenum includes first and second plenum sections, with
each plenum section extending along a respective one of the side
walls of the cabinet, each of said plenum sections including a
plurality of fore-to-aft spaced outlets arranged along the
respective one of said side walls of said cabinet.
7. The temperature controlled drawer assembly according to claim 6,
wherein each of the side walls of said drawer is formed with a
multiple, spaced holes, said holes being arranged directly adjacent
the outlets, at least when the drawer is wholly disposed within the
drawer space.
8. The temperature controlled drawer assembly according to claim 7,
wherein each of the holes in the drawer is enlarged relative to
each of the outlets such that each said hole spans a plurality of
the outlets of the plenum.
9. The temperature controlled drawer assembly according to claim 6,
wherein each of the first and second plenum sections includes an
enlarged section leading from the fan, with each of the first and
second plenum sections tapering away from the enlarged section.
10. The temperature controlled drawer assembly according to claim
4, further comprising: an enlarged opening, formed in the back wall
of the drawer, opposing said fan, said fan being adapted to draw
the flow of air from the drawer through said enlarged opening.
11. The temperature controlled drawer assembly according to claim
1, further comprising: a drip pan positioned below said temperature
adjusting device for collecting moisture.
12. The temperature controlled drawer assembly according to claim
11, wherein said drip pan is directly accessible from with said
drawer space upon removal of said drawer.
13. The temperature controlled drawer assembly according to claim
1, wherein the temperature adjusting device constitutes a heat sink
including a cold side and a hot side, said fan being disposed
directly adjacent said cold side.
14. The temperature controlled drawer assembly according to claim
13, further comprising: an additional fan disposed directly
adjacent the hot side of the heat sink for dissipating heat from
the hot side.
15. The temperature controlled drawer assembly according to claim
1, wherein said drawer space is defined by a liner positioned
within said cabinet.
16. The temperature controlled drawer assembly according to claim
15, wherein the liner is thermoformed of plastic.
17. The temperature controlled drawer assembly according to claim
1, further comprising: a magnetic seal between the front wall of
the drawer and the cabinet.
18. The temperature controlled drawer assembly according to claim
17, wherein the magnetic seal includes a gasket disposed on said
front wall of said drawer.
19. The temperature controlled drawer assembly according to claim
1, wherein the cabinet constitutes an end table.
20. The temperature controlled drawer assembly according to claim
19, wherein the end table constitutes a night stand.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a thermoelectric
temperature controlled device including a drawer moveable within a
cabinet designed to resemble a standard household end table, such
as a night stand.
[0003] 2. Discussion of the Prior Art
[0004] Thermoelectric devices which can selectively maintain their
contents at an elevated or reduced temperature are known in the
art. Such a device traditionally contains a power supply which
provides energy necessary to move electrons through energy states
across a bimetallic heat sink. As the electrons move from a lower
energy state to a higher energy state, a cold junction is produced.
Heat absorbed at the cold side is pumped to a hot side in
proportion to the current supplied. By reversing the direction of
the current, and therefore the heat flow, it is possible to change
from a cooling device to a heating device.
[0005] People normally keep their beverages and other food items in
a refrigerator located in a kitchen because of the necessity, or
simply the desire, to maintain the particular items at a reduced
temperature. With such a typical arrangement, when a cooled
beverage is desired, a person must travel through the house to the
refrigerator in the kitchen. Under certain circumstances, it may
not be convenient, or even possible, to obtain a beverage or the
like from a kitchen refrigerator. It has also been known to place a
mini-refrigerator in area of a household remote from a kitchen.
However, such mini-refrigerator units are typically not
aesthetically appealing, but rather stand out wherever they are
placed.
[0006] Portable coolers could be used to store such items in
potentially convenient locations, but this creates other problems.
First, these passive coolers are typically only insulated boxes
without any refrigeration systems and only function to maintain the
difference between the internal and external temperatures.
Therefore, in order to keep the contents at a reduced temperature,
an additional cooling device must be used. The items could be
placed in a refrigerator or freezer for a period before being
placed in the cooler, or ice packs could be placed in the cooler to
prolong the cooled state of the food items. Of course,
non-refrigerated coolers only maintain the temperature of its
contents. Because the cooler does not have any cooling device of
its own, once the ice melts, or the items lose their initial cooled
state, the entire cooler will cease to cool the items.
[0007] There have been developed systems for cooling using
thermoelectric devices. These systems generally use a heat sink to
dissipate heat from the device. In a typical heat sink arrangement,
a heat generating device is provided with a number of electrically
conductive fingers or fins which conduct excess heat away from the
heat generating device. The excess heat is dissipated through the
fingers. The amount of heat dissipated can be increased by forming
the fingers with greater surface areas and/or creating an air flow
across the fingers. Generally, in thermoelectric cooling devices, a
fan draws air from inside a cooling chamber and blows the air
across the cold side of a heat sink. Electric current flowing
through the thermoelectric device causes heat to flow from the cold
side to the hot side. As such, heat is extracted from the air
inside the cooling chamber and drawn across the heat sink to the
hot side, where the heat is dissipated.
[0008] Accordingly, small devices have been developed which
actively cool their contents without bulky traditional
refrigeration systems. The system described in U.S. Pat. No.
5,301,508 to Kahl et al. represents a portable container
incorporating a cooling device. Essentially, the system represents
a traditional passive cooler with a small removable refrigeration
apparatus installed therein without any substantial air circulation
apparatus. Although this system will actually cool the contents of
the cooler, it is not very efficient. First, the location of the
thermoelectric cooling element is on a wall adjacent to the
opening. Therefore, when the cooler is opened, the fan inside the
thermoelectric cooling element is drawing in ambient air. In
addition, the thermoelectric unit does not efficiently distribute
the cooled air throughout the chamber.
[0009] U.S. Pat. No. 3,733,836 to Corini discloses a cooling unit
including an inner shell with a plurality of holes inside an
associated cooling chamber. By positioning a thermoelectric device
and fan between the inner shell and an outer shell, the fan
distributes cooled air through the gap formed between the two
shells. The cooled air then enters the cooling chamber through the
holes. Although such a configuration works well for a device such
as an ice cream cart, inserting a drawer into the cooling chamber
would prevent adequate cooling of the chamber. Additionally,
because air cannot flow across the hot side heat sink, the
potential efficiency of the thermoelectric device is reduced.
[0010] Based on the above, there exists a need for an efficient
thermoelectric device particularly adapted for conveniently storing
and cooling food items. In addition, there exists a need for a
compact thermoelectric cooling device which can be used in various
environments, particularly in connection with conveniently storing
food items in areas outside the kitchen.
SUMMARY OF THE INVENTION
[0011] The present invention is particularly directed to a cooling
unit using a thermoelectric device with a fan to circulate cooled
air throughout a cooling chamber. More specifically, a first fan is
provided to draw air from the cooling chamber and blow the air
across a cold side heat sink. The electric current supplied to the
thermoelectric device causes the cold side heat sink to draw heat
from the air and pass the absorbed heat to the hot side heat sink
where it can be dissipated. The entire apparatus is preferably
designed to resemble an end table, such as a nightstand, found in a
typical household.
[0012] In a preferred form of the invention, a drawer is installed
inside the thermoelectric cooling device. The fan blows cooled air
from between an inner liner and an outer liner, and the drawer is
designed to allow for the circulation of air through the drawer. In
accordance with the invention, the same fan also draws air from
inside the drawer, causes the air to flow over the cold side heat
sink and then recycles the air back into the drawer. Specifically,
the drawer is designed with various ports and openings to
accommodate the desired circulation. In accordance with the most
preferred form of the invention, the drawer is essentially
constituted by a frame with many holes, rather than a traditional
drawer having solid side walls.
[0013] The thermoelectric device is also provided with a second fan
to increase system efficiency. As the first fan draws the air from
inside the cooling chamber and blows the air across the cold side
heat sink prior to returning the cooled air to the cooling chamber,
the thermoelectric device causes absorbed heat to travel to a hot
side heat sink. The second fan is located near the hot side heat
sink such that the excess heat can be more quickly dissipated. With
both the cold side heat sink fan and the hot side heat sink fan
running, the temperature regulating efficiency of the
thermoelectric device can be greatly increased.
[0014] Because the heat flow of a thermoelectric device depends
upon the direction of current flow, the thermoelectric cooling
drawer of the invention can also be used to heat the contents of
the drawer. To change the thermoelectric device from a cooling mode
to a heating mode, a switch is provided to reverse the polarity of
the power supply. This causes the heat flow direction to be
reversed and heat to build up on the drawer side of the
thermoelectric device.
[0015] Additional objects, features and advantages of the invention
will become more readily apparent from the following detailed
description of a preferred embodiment thereof, when taken in
conjunction with the drawings wherein like reference numerals refer
to corresponding parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a preferred embodiment of
the thermoelectric cooling device of the invention;
[0017] FIG. 2 is a perspective view of a drawer, incorporated in
the thermoelectric cooling device of FIG. 1;
[0018] FIG. 3 is a front perspective view of the cooling chamber
portion of the thermoelectric cooling device of the invention;
[0019] FIG. 4 is a cross-sectional top view of a rear portion of
the thermoelectric cooling device of FIG. 1; and
[0020] FIG. 5 is a cross-sectional side view of the rear portion of
the thermoelectric cooling device of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] FIG. 1 depicts an embodiment of a thermoelectric cooling
device 10 constructed in accordance with the present invention. In
the preferred embodiment, a cabinet 15 is provided which
essentially resembles a nightstand used in a typical bedroom, but
could equally constitute another type of end table such as that
found in a living room or a family room. Cabinet 15 includes at
least a top 16, opposing side walls 17 and a front 18. Inside
cabinet 15 is defined a drawer space 20 which opens at front 18 of
cabinet 15. Disposed inside drawer space 20 is a drawer 22. The
drawer 22 is shown to include a face 23, two upstanding, spaced
apart sides 25 and 26, and a bottom 28 extending between sides 25
and 26. Opposite drawer face 23 is a substantially parallel back 30
as best shown in FIG. 2. Drawer 22 is preferably suspended on rails
32 which mate with corresponding rail structure inside drawer space
20 to allow for sliding movement of drawer 22 in and out of cabinet
15. Each of the sides 25 and 26 is provided with enlarged vent
holes 35, with enlarged vent holes 35 being preferably rectangular
in shape and spaced along the length of a respective side 25, 26 to
allow for air flow. At the front 18 of cabinet 15, slightly spaced
from and extending about drawer space 20, is an annular magnetic
strip 36, arranged for sealing face 23 to front 18 when drawer 22
is closed, as will be discussed further below.
[0022] FIG. 2 shows the entire structure of drawer 22 which has
been removed from cabinet 15. Drawer 22 basically constitutes a
box, with the top removed and vent holes 35 provided. The main
distinction between a standard cabinet drawer and drawer 22 of the
invention is the structure of sides 25 and 26, as well as back 30.
On each of sides 25 and 26, three pairs of vent holes 35 are
preferably provided. Back 30 has an enlarged opening 54. When
inserted into space 20, vent holes 35 and opening 54 allow for the
circulation of air, as will be detailed below. Drawer wheels 56 are
shown below rails 32 on each of sides 25 and 26. In general, the
construction and operation of rails 32 and wheels 56 are widely
known in the art and therefore will not be described in detail
here.
[0023] FIG. 2 also shows a gasket 58 disposed on an inside of face
23. Because sides 25 and 26 are preferably elongated and parallel,
drawer 22 is generally rectangular in shape. When drawer 22 is
closed, gasket 58 abuts front 18 to effectively seal space 20 and
prevent any influx of ambient air. In a preferred embodiment,
gasket 58 has an internal metal member (not shown) which becomes
seated against magnetic strip 36 upon closing of drawer 22 in order
to provide a substantially air tight seal. Of course, other sealing
arrangements could be used and the positioning of the gasket 58 and
magnetic strip 36 could be reversed.
[0024] FIG. 3 shows the inside of drawer space 20, with drawer 22
removed. As shown, drawer space 20 is defined by two spaced apart
side walls 70 and 71, a bottom wall 72 and a back wall 73, all of
which are preferably, integrally formed by a single, thermoformed
plastic liner. Located at each of side walls 70, 71 is a vent 75
which is preferably flush with the respective side wall 70, 71. A
plurality of fore-to-aft spaced outlets in the form of slits 78 are
present along vents 75.
[0025] In the center of back wall 73 is a first or inside fan 84.
Attached to the sides of, and in fluid communication with, inside
fan 84 are two plenums 85 and 86. Where plenums 85 and 86 attach to
inside fan 84, each plenum 85, 86 is defined by an enlarged section
87. Each plenum 85, 86 extends laterally from adjacent inside fan
84 completely to a respective side wall 70, 71 within drawer space
20, as best shown in FIGS. 3 and 4. Below inside fan 84 is a drip
pan 89. In the embodiment shown, drip pan 89 has an associated
drain 93 used to direct condensate through bottom wall 72. Although
not shown, drain 93 preferably leads to a collecting pan located
within cabinet 15 below drawer space 20. In the alternative, drain
93 need not be provided, wherein drip pan 89 will simply function
to collect any condensate. As clearly shown in FIG. 3, drip pan 89
is readily accessible upon removing drawer 22.
[0026] Below slits 78 in vent 75 on each of side walls 70 and 71
are provided cabinet rails 96, 97 and a respective wheel or roller
98. Roller 98 and rails 96 and 97 are of a conventional design and
function to support/guide drawer 22 into and out of drawer space 20
in combination with rails 32 and drawer wheels 56 in a manner known
in the art as discussed above. In general, when drawer 22 is
inserted into drawer space 20, rails 96, 97 and rollers 98 mate
with drawer rails 32 and drawer wheels 56 to allow drawer 22 to
slide in and out of drawer space 20.
[0027] As best shown in FIGS. 4 and 5, immediately behind drawer 22
is inside fan 84. Plenums 85 and 86 can be seen extending laterally
from adjacent fan 84. Behind inside fan 84 is an outside fan 120.
Between inside fan 84 and outside fan 120 is a heat sink 124 which
forms part of a thermoelectric temperature regulating device. Heat
sink 124 is divided into a cold side 126 and a hot side 128. When
heat sink 124 is in cooling mode as shown in these figures, cold
side 126 is located near inside fan 84, and hot side 128 is located
near outside fan 120. On at least the surface closest to fans 84
and 120, heat sink 124 is provided with a plurality of fingers or
fins 129 and 130 to assist in heat dissipation and absorption.
[0028] Adjacent hot side 128 of heat sink 124 is a power supply 140
which delivers electricity to heat sink 124. Power supply 140
includes a standard three-prong plug 142 which is adapted to fit
into a common household grounded socket. Via a switch wire 144, a
control box 145, incorporating control circuitry and an adjustable
control element or switch (not shown), is electrically connected to
power supply 140 to direct power to heat sink 124. Control box 145
is connected to both cold side 126 and hot side 128 through a cold
side wire 146 and a hot side wire 148, respectively. Switch box 145
is shown as being attached to a rear of cabinet 15, but may be in
any location, as long as the electrical connections are maintained.
As indicated above, control box 145 preferably houses a rotary or
other switching arrangement that is used to selectively regulate
the power transferred from supply 140 to heat sink 124. As
mentioned above and shown in FIG. 5, drip pan 89 extends below cold
side 126 and is preferably accessible upon removing drawer 22 from
drawer space 20. In addition, a second drip pan 148 is located
below hot side 128 to funnel any condensate into a second drain
150.
[0029] When thermoelectric cooling device 10, and hence control box
145, is in a COOL mode, a maximum temperature is selected through
control box 145. When, via thermistor 160 which is linked to switch
box 145 (see FIGS. 3 and 4), control box 145 detects an over
temperature condition, both inside fan 84 and outside fan 120 are
activated to blow air across fins 129 and 130 of heat sink 124.
Inside fan 84 draws air from inside drawer 22, through opening 54,
and blows the air across fins 129 of cool side 126. Because the
current is flowing from cold side 126 to hot side 128 and the
current pulls the heat with it, cold side 126 draws heat from the
air into heat sink 124. The inclusion of fins 129 and 130 allows a
more efficient transfer of heat at both sides of heat sink 124.
[0030] Once the air is cooled, i.e., the heat is absorbed into heat
sink 124, the air is blown into plenums 85 and 86. Because plenums
85 and 86 are provided with slits 78 of vents 75 on side walls 70
and 71, the air is blown through plenums 85 and 86 and out slits
78. When drawer 22 is inserted into drawer space 20, vent holes 35
line up with slits 78 to allow the air to directly enter the
interior of drawer 22. Most preferably, each vent hole 35 aligns
with multiple slits 78 such that, as the air flowing out of slits
78 deaccelerates and expands in breadth, substantially the entire
air flow will be directed into drawer 22. The air is then
recirculated within drawer 22 and drawn to inside fan 84 through
opening 54. The heat absorbed through fins 129 on cold side 126 is
moved through heat sink 124 to hot side 128. Because hot side 128
also has its own fins 130, outside fan 120 assists in the
dissipation of the absorbed heat by blowing air across fins 130 and
out a plurality of louvers 152 provided at the back face of cabinet
15.
[0031] Thermoelectric cooling device 10 of the invention may also
be used to heat the contents of drawer 22. Preferably, control box
145 can accessed to selectively determine the direction of the
current flow through heat sink 124. Because of the thermoelectric
properties of heat sink 124, when the current flows from cold side
126 to hot side 128, the current pulls the heat with it. Therefore,
when control box 145 is placed in a COOL setting, the current is
caused to flow to cold side 126 of heat sink 124. When a HOT
setting is selected, the current flows in the opposite direction
through heat sink 124, and hot side 128 and cold side 126 actually
flip, i.e., the side adjacent inside fan 84 becomes the hot side
and the side adjacent outside fan 120 becomes the cold side. With
the current reversed, outside fan 120 draws in cool air through
louvers 152 and blows the air across the fins on the cold side of
heat sink 124. Heat sink 124 absorbs heat from the air and pulls it
across to the hot side. Air, which has been drawn through opening
54 from inside drawer 22 is then blown across fins 130 on the hot
side, where it absorbs the excess heat which was pulled from the
outside air. Finally, the treated air is then blown through plenums
85 and 86 and back into drawer 22.
[0032] As indicated above, drip pans 89 and 148 are located to
collect any condensate which may develop on fins 129 and 130 on
either side of heat sink 124. When the temperature of fins 130
drops below 0.degree. C., ice will form on them. When the
temperature increases, either because device 10 has been shut off
or due to a low power state, the ice will melt. The melting ice
will be collected in drip pans 89 and/or 148. The invention
requires two drip pans 93 and 148 because, depending upon the
setting at control box 145 and the direction of current flow, ice
and water may collect on either side of heat sink 124. At this
point, it should be realized that drip pans 89 and 148 may share a
common drain.
[0033] It should also be realized that the switch associated with
control box 145 may take on a variety of forms. In its simplest
form, the switch would be a three-position switch, which can be set
to COOL, HEAT, or OFF positions, with the current through heat sink
124 being constant, but the direction being alterable. In a more
complex scheme, the switch can be constituted by a temperature
dial, with control box 145 including electronic logic controls
through which a user would select a desired temperature. Using the
thermistor 160, the controls would be able to determine the current
temperature within drawer 22 and determine if device 10 should be
placed in a COOL, HEAT or OFF mode. Therefore, control box 145
could automatically change the direction of current flow in
response to the temperature reading from thermistor 160. Control
box 145 could also adjust the amount of current flowing through
heat sink 124 to vary the amount of heat transfer. Alternatively,
control box 145 may include a timer which would allow a user to set
the apparatus to automatically start-up at a desired time.
[0034] Although described with reference to a preferred embodiment,
it should be readily understood that various changes and/or
modifications could be made to the invention without departing from
the spirit thereof. For instance, a control switch could be placed
in various locations, including on drawer front 23 or on the side
of cabinet 15. Additionally, rather than cabinet 15 be incorporated
into a nightstand, thermoelectric cooling device 10 may take the
form of other household or office cabinetry. In any event, it is
preferable that device 10 remain inconspicuous, while enabling the
cabinet to perform multiple functions, i.e., as a cooling device
and a table. In addition, thermoelectric cooling device 10 of the
invention may include two temperature adjusting drawers, i.e., a
cooling drawer and a warming drawer. In such an arrangement, the
hot side for the cooling drawer would preferably be positioned such
that when air is blown across its fins, the warmed air would be
circulated through the warming drawer. Otherwise, the structure and
function of the cooling drawer would be the same as in the
embodiment discussed above. Alternatively, the warming drawer may
contain an electric heater. Preferably, the warming drawer would be
defined by a separate liner arranged within the cabinet above the
cooling drawer with sufficient insulation therebetween. In any
event, the invention is only intended to be limited by the scope of
the following claims.
* * * * *