Note: Descriptions are shown in the official language in which they were submitted.
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This appllcation is a division of parent application 392,517
filed December 17, 1981.
l'}lERMOELECTRIC DEVICE AND PROCESS ~IOR MAKING THE SAME
FIELD OF INVE~TION AND PRIOR ART
..
This invention relates to a thermoelectric device and a
process for making the same.
The invention i~ particularly directed to improvements in
the cooling device illustrated in U. S~ Patent 4,107,934.
Thermoelectric devices powered by a thermoelectric element
of the Peltier type are well known in the art, as shown by the
above-identified patent and the patents cited therein. ~he
device shown in U. S. Patent 4~107,934 has the advantage that the
thermoelectric element is not completely imbedded in the insulat-
ing wall, but has the disadvan~age that the thermoelectric element
is exposed to the ambient atmosphere and is susceptiblP to mal-
functioning in inclement weather or in marine usage. It also has
the disadvantage that the external thermal sink is exposed to
accidental blows which can damage the thermoelectric element. It
further has the disadv~ntage that it is expensive and difficult to
manufacture.
OBJECTS OF THE INVENTION
It is an object of the invention to provide an improved
thermoelectric device and process for making the same. It is a
further object of the invention to provide an improved thermo-
electric cooling device. It is a further o~ject of the invention
to provide for the economic and facile manufacture of such devices
It is a still further object of the invention to provide thermo-
electric devices of the class described which are insensitive to
ambient ~onditions involving water, as in inclement weather and
in marine usage. Still another object of the invention is to
provide a thermoelectric device of the class described in which
the external thexmal sink is protected against accidental blows-
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which might damage the thermoelectric element.
BRIEF DESCRIPTION OF THE INVENTION
.
This invention relates to a thermoelectric device powered by
a thermoelectric element of the Peltier type which comprises an
insulatin~ wall Q~ foamed-in-place insulating foam cast about
an internal thermal sink in a manner which produces an inner and
outer shell portion on the insulating wall and a depression
therein which exposes a surface of the internal thermal sink, the
thermoelectric element being disposed in this depression in
heat-exchange with the surface of the internal thermal sink
exposed by the depression; and an annular resilient and compress-
ible sealing gasket disposed on the outer shell portion in sealing
contact with outer shell portion and an external thermal sink and
being compressible thereby, the sealing gasket heing maintained
under compression and the thermal sinks being maintained in heat-
exchange with the thermoelectric element by draw means which
draws the two thermal sinks toward each other sufficiently to
compress the gasket an~ to bring them into heat-exchange with the
thermoelectric element.
The inner and outer shell portions can be pre-formed or
formed from polyurethane foam in which the inner and outer shell
portions are formed in situ as a skin on the polyurethane foam.
This aspect of the invention also comprises a process which
comprises casting the insulating wall of foamed-in-place plastic
about the internal thermal sink in a manner which provides inner
and outer shell portions on the insulating wall and a depression
therein which exposes a surface ~f the internal thermal sink;
placing the thermoelectric element in the depression in heat-
exchange with the surface of the internal thermal sink exposed by
the depression; placing an annular resilient and compressible
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sealing gasket on the outer shell portion in position such that
it completely surrounds the depression and the thermoelectric
element therein; placing an external thermal sin~ in sealing
contact with the sealing yasket; and, drawing the two sinks
toward each other ~ntil the gasket is compressed and the thexmal
sinks are in heat-exchange with the thermoelectric element.
In the process, the inner and outer shell portions are either
pre-formed or, the insulating foam is a polyurethane foam which is
cast in such a manner as to form the inner and outer shell
portions in situ.
The invention also comprises electrical connectors which,
except for positive and negative contac~ points which project
through the outer shell portion in position to be connected to
the positive and negative poles, respectively, o ~he thermo-
electric element, are completely imbedded in the insulating wall
and electrically-connected with the contact points and in which
the contact points are covered by the annular sealing gas}cet and
thus protected from exposure to moisture.
According to another aspect of the invention, there is
provided a thermoe:Lectric cooling device having an insulating
wall with an insulated thermal sink imbedded in the insulation
thereo~ and having a surface thereof adjacent the surface of the
insulating wall and exposed by a depression therein which has a
thermoelectric device having a cold face and a hot ~ace
disposed in the depression with the cold face thereof in heat-
exchange with the surface of the internal thermal sink exposed by
the depression; an external thermal sink; and an annular resilient
and compressible sealing gasket surrounding the depression and
the thermoelectric element therein in sealing contact with the
3 insulating wall and the external thermal sink and under compression
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between the two~
~ dvantageously, too, the insulating wall has electrical
connectors imbedded in the insulation thereof which extend through
the outer surface thereo~ to the thermoelectric element and in
which the annular gasket overlies the outermost por-tion of the
exposed connectors and seals them against exposure to moisture.
A further aspect of the invention comprises a thermoelectric
cooling device having an insulating wall having an internal
thermal sink imhedded therein and a flat external thermal sink
parallel to and spaced from the insulating wall characterized in
that the insulating wall has a rim extending around ~ut spaced
from the external thermal sink of such height that the edge of
the rim and the outer flat surface of the external thermal sink
are substantially in a common plane. The presen-t divisional
application is directed to this further aspect of the invention~
In_*he drawings.
FIG. 1 is an isometric. view of a portable refrigerator
of the invention;
FIG~ 2 is an exploded view in isometric of the box portion
of FIG~ l;
FIG. 3 is a fragmentary view of a cross-section ta~en along
line 3-3 of FIG. l;
FIG. 4 is an exploded view in isometric of FIG. 3; and,.
FIG. 5 is a plan view, looking in the direction of the
arrows in FIG. 4~
DETAILED DESCRIPTION OF THE INVENTION
... .. .. _ .
ln the embodiment of the invention shown in the drawings,
there is provided a portable refrigerator 10, comprising a con-
tainer portion 12 and a cover portîon 14 fas~ened thereto by
30 hasps 16 on one side, and hinges, not shown, on the other side~
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The container proper is made up of an outer shell 18 and
an inner shell 20, as better seen FIGo 2. The inner shell 20,
advantageously, is made of plastic, but could, if desired, be
made of aluminum or other heat-conducking metal. Fitted snugly
against the ends and bottom of the inner shell 20 is a thermal
sink 22. At each end of the thermal sink 22 is a U-shaped
thermal sink 24 bolted to the end walls 26 of the thermal sink
22. The bolts 28 extend out beyond the flat end or bight 30 of
the U-shaped thermal sink 24, as clearly shown in FIGS. 2 and 3.
When the parts are assembled, laterally~nding side rims 32 of
the inner shell 29 overlap the sides 34 of the outer shell 18
and the ends 36 abut the end walls 38 of the outer shell 18 and
are countersunk therein, as ~n at 39, th-~ hold~g the inner shell 20
spaced from ~he side, ends, and bottom of the outer shell 18.
The end walls 38 have an inset panel 40 fitted in chamfers
42 in the end wall 38. The inset panel 40 has a square hole 44
which is a little smaller than the face 30 of the thermal sink 24
and oriented with respect thereto, as shown in FIG. 5. It forms
a depression in the end walls 38 which expose the face 30 of the
thermal sink 24.
The inset 40 has two electrical contacts 46 and 48 which are
connected by electrical wires 50 and 52 to a pigtail 54, which
extends out rom the interior through the bottom portion of one
of the walls 38 and is connected to a polarized plug 56, which is
suitable for insertion into the li~hter socket in a motor vehicle,
such as a car, an airplane, vr a boat.
When this much of the refrigerator is assembled, it is
placed in a press and injected with a plastic foam-forming com-
position to fill the space ~etween the inner and outer shell with
foam insulation and to imbed the wires 50 and 52 and the inner
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portion of the el~ctric cord 54 in the insulation.
Ther~after, the external portions 58 and 60 of the electricalconnec~ors 46 and 48 are connec~ed by electrical wires 62 and 64
to the positive and negative sides of the thermal electric el~t
66 which has a flat face 68 in surface-to-surface contact with
the flat face 30 of the thermal sink 24, and a flat face 70 in
surface~to-surface contact with an inner flat face 72 of an
external thermal sink 74~ which is bolted up tight with the
thermoelectric element 66 in compression between the faces 72
and 30 by the draw bolts 28.
Before the external thermal sink 74 is put into place, ~here
i~ placed around the thermoelectric element 66, an annular sealing
gasket 76, composed of resilient and compressible material. This
gasket is held in place by the draw bolts 28 passing up through
the slots 78 and 80 in the annular gasket 76. The end 82 of the
annular gasket is made long enough to overlap substantially the
electrical connectors 46 and 48, as best s~ in FIG. 3 and, is of such
thickne~s that, when the external thermal sink 74 is bolted onto
the thermoelectric element 66, the gasket is put in compression,
thereby completely isolating the thermoelectric element from
ambient conditions, such as moisture, and the like. At the same
time, the overlapping portion 82 isolates the electrical connectors
~6 and g~ and electrir~l wires 62 and 64 from exposure to ambien~ conditions.
The external thermal sink 74 is made of material of high
heat-ccnductivity, for e~le, aluminum, has a plurality o vertically-
~ding ribs 84 and at least laterally-extending fins 86 and 87
extending ~tera11y franthe centr~ panel 88, in ~ ch the r~s 84 are
formed. The fins 87 are planar with their outer surfaces ~nd the
outer ends of the ribs 84 lying in a common plane.
3~ The external th~rmal sink 74 is rectangular in shape and of
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a thickness so correlated with the indentations in the ends 38
of the container that the outermost surface 90 of the external
thermal sink 74 is flush with the outermost sur~ace of rim 92
of the ends 38.
The cover 14 is independently produced and filled with foam
insulation and then hinged to the container 12, as already
described.
Thus, there is provided a portable refrigerator container
which is simple and effective in construction, sy~netrical in
outline, contains no external.thermal sinks which project beyond
the walls thereo, and in which the thermoelectric elements and
the electrical connections are completely isolated from ambient
conditions~
There is also provided a new and improved process in which
the insulating wall is cast of foamed-in-place insulating foam
about the internal thermal sink in a manner which provides inner
and outer shell portions on the insulating wall and in which ~he
parts are assemb:Led in a manner to provide a portable refri~erator
in which the thermoelectric element and the electrical connections
thereto are isolated from and protected from ar~ient conditions.
While the specific embodiment discloses a pre-formed con-
tainer with inner and outer shell portions, it is to be understood
that the inner and outer shell portions can be formed in situ by
using a polyurethane foam of the kind which, when cast in a
suitahle mold, produces a dense skin.
It is to be understood that the invention is not to be
limited to the exact details of operation or structure shown and
described, as obvious modifications and equivalents will be
apparent to one skilled in the art.
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