Heat exchanger unit with conductive discs

A heat exchange unit for use in containers for cooling a food or beverage. The heat exchange unit includes inner end outer vessels with inner vessel having a plurality of thermally conductive discs in thermally conductive contact with an inner surface thereof. An adsorbent material is disposed between adjacent discs is compacted between them to provide maximum adsorbent material per unit volume. The outer surface of the inner vessel defines a plurality of grooves and is in thermally conductive contact with the inner surface of the outer vessel. The grooves provide flow paths for a gas such as carbon dioxide which is adsorbed onto the adsorbent material to flow and exit the heat exchange unit and to carry with it, the heat contained in the food or beverage, thereby lowering its temperatures.

FIELD OF THE INVENTION 
The present invention relates generally to a heat exchange unit for use in 
containers for self-chilling foods or beverages and more particularly to a 
heat exchange unit of the type in which temperature reduction is caused by 
the desorption of a gas from an adsorbent disposed within the heat 
exchange unit. 
DESCRIPTION OF THE ART 
Many foods or beverages available in portable containers are preferably 
consumed when they are chilled. For example, carbonated soft drinks, fruit 
drinks, beer, puddings, cottage cheese and the like are preferably 
consumed at temperatures varying between 33.degree. Fahrenheit and 
50.degree. Fahrenheit. When the convenience of refrigerators or ice is not 
available such as when fishing, camping or the like, the task of cooling 
these foods or beverages prior to consumption is made more difficult and 
in such circumstances it is highly desirable to have a method for rapidly 
cooling the content of the containers prior to consumption. Thus a 
self-cooling container, that is, one not requiring external low 
temperature conditions is desirable. 
The art is replete with container designs which incorporate a coolant 
capable of cooling the contents without exposure to the external low 
temperature conditions. The vast majority of these containers incorporate 
or otherwise utilize refrigerant gases which upon release or activation 
absorb heat in order to cool the contents of the container. Other 
techniques have recognized the use of endothermic chemical reactions as a 
mechanism to absorb heat and thereby cool the contents of the container. 
Examples of such endothermic chemical reaction devices are those disclosed 
in U.S. Pat. Nos. 1,897,723, 2,746,265, 2,882,691 and 4,802,343. 
Typical of devices which utilize gaseous refrigerants are those disclosed 
in U.S. Pat. Nos. 2,460,765, 3,373,581, 3,636,726, 3,726,106, 4,584,848, 
4,656,838, 4,784,678, 5,214,933, 5,285,812, 5,325,680, 5,331,817, 
5,606,866, 5,692,381 and 5,692,391. In many instances the refrigerant gas 
utilized in a structure such as those shown in the foregoing U.S. Patents 
do not function to lower the temperature properly or if they do, they 
contain a refrigerant gaseous material which may contribute to the 
greenhouse effect and thus is not friendly to the environment. 
To solve problems such as those set forth above in the prior art, applicant 
is utilizing as a part of the present invention an adsorbent-desorbent 
system which may comprise adsorbent materials such as zeolites, cation 
zeolites, silicagel, activated carbons, carbon molecular sieves and the 
like. Preferably the present invention utilizes activated carbon which 
functions as an adsorbent for carbon dioxide. A system of this type is 
disclosed in U.S. Pat. No. 5,692,381 which is incorporated herein by 
reference. 
In these devices the adsorbent material is disposed within a vessel, the 
outer surface of which is in contact thermally with the food or beverage 
to be cooled. Typically, the vessel is connected to an outer container 
which receives the food or beverage to be cooled in such a manner that it 
is in thermal contact with the outer surface of the vessel containing the 
adsorbent material. This vessel or heat exchange unit is affixed to the 
outer container typically to the bottom thereof and contains a valve or 
similar mechanism which functions to release a quantity of gas, such as 
carbon dioxide which has been adsorbed by the adsorbent material contained 
within the inner vessel. When opened the gas such as carbon dioxide is 
desorbed and the endothermic process of desorption of the gas from the 
activated carbon adsorbent causes a reduction in the temperature of the 
food or beverage which is in thermal contact with the outer surface of the 
inner vessel thereby lowering the temperature of the food or beverage 
contained therein. 
To accomplish this cooling it is imperative that as much carbon dioxide be 
adsorbed onto the carbon particles contained within the inner vessel and 
further that the thermal energy contained within the food or beverage be 
transferred therefrom through the wall of the inner vessel and through the 
adsorbent material to be carried out of the heat exchange unit along with 
the desorbed carbon dioxide gas. It is known in the art that most 
adsorbents are poor conductors of thermal energy. For example, activated 
carbon can be described as an amorphic material and consequently has a low 
thermal conductivity. By compacting the activated carbon to the maximum 
amount while still permitting maximum adsorption of the carbon dioxide gas 
thereon does assist some in conduction of thermal energy. However, 
sufficient thermal energy conduction is not accomplished simply by the 
compaction of the carbon particles. To allow better heat transfer of the 
heat contained in the food or beverage it is necessary to incorporate a 
thermal conductivity enhancer heat transfer means which will assist in 
conducting heat from the surface of the inner vessel through the carbon 
particles disposed within the inner vessel to be carried out with the 
desorbed carbon dioxide gas as it leaves the heat exchange unit. 
As above pointed out one of the problems with conventional arrangements 
utilizing adsorbent desorbent systems is that the flow of desorbed gas 
does not efficiently remove the heat from the food or beverage in contact 
with the outer surface of the heat exchange unit. Although part of the 
desorbed gas leaves the adsorbent material adjacent the nearest wall and 
then travels along the vessel wall to the exit valve, a significant 
portion also permeates through the adsorbent and through the exit valve of 
the vessel without coming into contact with the vessel wall and thus a 
significant amount of the potential cooling capability of the desorbed gas 
is effectively wasted. Also, as above pointed out, it is important that 
the adsorbent material, such as the activated carbon particles, be 
compacted as highly as possible without substantially reducing the 
porosity of the body of adsorbent material to such a degree that its 
capability of adsorbing the carbon dioxide gas or the retardation of the 
rate of desorption from within the body of the absorbent is not 
deleteriously affected. 
SUMMARY OF INVENTION 
A heat exchange unit for use in a container for chilling a food or beverage 
contained therein wherein the heat exchange unit includes a thermally 
conductive outer vessel having a wall with inner and outer surfaces and a 
closed end. A second vessel having an open end inserted within and in 
thermal contact with the inner surface of the outer vessel to provide a 
thermally conductive path therebetween. The outer surface of the inner 
vessel defining with the inner wall of the outer vessel a plurality of 
passage ways for conducting gas. Said inner vessel being disposed with its 
open end adjacent the closed end of said outer vessel. The interior of 
said inner vessel having disposed therein a plurality of layers of an 
adsorbent material with thermally conductive discs disposed between 
adjacent layers of said adsorbent material.

DETAILED DESCRIPTION 
Referring now to the drawings there is shown in FIG. 1 a beverage can 10 
having disposed therein a heat exchange unit 12. The heat exchange unit 12 
is affixed to the bottom 14 of the beverage can 10 through the utilization 
of a valve mechanism 16 which is secured by crimping to an opening in a 
cap 18 secured to the top of the heat exchange unit and closing the same. 
As shown by the dashed line 17 the cap 18 may be dispensed with and the 
heat exchange unit may be formed or necked inwardly as a unitary vessel 
which is secured to the valve mechanism 16. 
The heat exchange unit 12 includes an outer vessel 20 which includes an 
outer wall 22 and an inner wall 24 and a closed bottom 26. Also included 
as part of the heat exchange unit is an inner vessel 30 having an outer 
wall 32 and an inner wall 34 and an open end 36. The end opposite the open 
end 36 namely end 38 is closed. 
Disposed within the interior of the inner vessel 30 is a plurality of 
layers 40, 42, 44, 46 - - - N of adsorbent material. The use of the 
designator N indicates that there may be any number of layers as may be 
needed for the application under consideration depending upon the food or 
beverage to be chilled and the amount of adsorbent to be contained within 
the heat exchange unit. Also disposed within the interior of the inner 
vessel 30 are a plurality of thermally conductive discs 48, 50, 52, 54 - - 
- N again indicating that there may be any number of such thermally 
conductive discs. As is illustrated, the discs are spaced apart and layers 
of adsorbent material such as activated carbon 40, 42, 44, 46 - - - N are 
interposed between adjacent ones of the thermally conductive discs. Each 
of the thermally conductive discs is in thermally conductive contact with 
the inner surface 34 of the inner vessel 30 and extends completely 
thereacross. Preferably the inner and outer vessels as well as the 
beverage can 10 are cylindrical in construction and the discs are also 
cylindrical in construction. 
As is more clearly shown in FIGS. 5 and 6 to which reference is hereby made 
a thermally conductive disc such as shown at 60 includes a plurality of 
openings as shown at 62 through 74 defined therethrough. Although there 
are seven such openings shown in the disc 60 there may be any number 
desired depending upon the particular construction desired. As is 
illustrated particularly in FIG. 6 the disc 60 is formed of solid material 
except for the openings 62 through 74 therethrough. The diameter of the 
disc 60 is such that it is press fitted into the interior of the inner 
vessel 30 of the heat exchange unit 12 so that the outer periphery 76 
accomplishes an interference fit with the inner surface 34 of the inner 
vessel 30 and is in excellent thermally conductive contact therewith. By 
the interference fit the disc is also mechanically secured to the inner 
vessel 30 for reasons to be explained hereinafter. 
During construction what typically will occur is that the layers of 
adsorbent material are placed into the inner vessel 30 with the first 
being such that it contacts the bottom 38 thereof. After the layer of 
material is disposed within the inner vessel and against the bottom 38 
thereof the top most (as viewed in FIG. 1) thermally conductive disc such 
as shown at 60 is inserted in place and press fitted so that there is an 
intimate thermal contact with the inner surface 34 of the inner vessel 30. 
If desired, pressure can be applied to compress the adsorbent particles, 
such as particles of activated carbon, to the extent desired to enable 
adsorption of a maximum amount of a gas to be inserted under pressure 
therein, such for example as carbon dioxide. Additional layers of the 
activated carbon can then be disposed one after the other with a thermally 
conductive disc being placed thereon and press fitted into the inner 
vessel 30 with appropriate compression as above-described until the entire 
vessel 30 is filled with layers of the activated carbon adsorbent material 
sandwiched between thermally conductive members such as the discs or the 
bottom of the inner vessel 30. As will now be appreciated, by securing the 
discs 60 mechanically the integrity of the compaction of the carbon 
particles is maintained. 
It should be recognized that it is very important to compact the carbon 
particles to the maximum extent possible without destroying the ability of 
the particles to adsorb the carbon dioxide gas. Such compaction is 
required to obtain the greatest amount of carbon particles within the 
given space allocated within a particular heat exchange unit. The greater 
the amount of carbon the larger the amount of carbon dioxide gas can be 
adsorbed per unit volume which, in turn, increases the cooling effect. 
That is, more carbon given, more carbon dioxide gas adsorbed, which give 
more cooling on desorption. Therefore, it is seen that the plurality of 
thermally conductive discs when inserted, compact the carbon particles and 
since the discs achieve an interference fit with the interior surface 34 
of the container 30, the compaction of each layer is retained permanently. 
As is illustrated in FIGS. 2-4 the inner vessel 30 includes an outer 
surface 32 which has a diameter which is substantially identical to the 
inner diameter of the outer vessel 20 so that the inner vessel with its 
open end 36 facing the closed end 26 of the outer vessel is pressed fitted 
into the outer container. By such press fitting, the outer surface 32 of 
the inner vessel 30 is in intimate thermal conductivity with the outer 
vessel 20. Along the surface 32 of the inner vessel 30 there are provided 
a plurality of grooves or slots as shown at 72, 74 and 76 in FIG. 3. These 
slots although illustrated as being vertical may be provided in any 
configuration desired such as helical, in a spiral fashion, tartiutous or 
the like. The function of the slots is to provide along the inner surface 
24 of the outer container 20 a passageway through which gaseous material 
may pass when the same is flowing in the heat exchange unit. The flowing 
of such gas, such as carbon dioxide under pressure, will occur during two 
separate events. The first of these is when the heat exchange unit is 
charged with the gas such as carbon dioxide to be adsorbed onto the 
particles of adsorbent material such as the activated carbon particles 
contained within the interior of the inner vessel 30. Subsequently, when 
the valve 16 is activated by depressing the same downwardly the adsorbed 
gas under pressure is released and upon being desorbed will try to escape 
through the valve 16 to the atmosphere. By providing the holes in the 
conductive disc 60 as shown in FIGS. 5 and 6 and the slots or grooves as 
shown in FIGS. 2 and 3 in the outer surface 32 of the inner vessel 30 the 
desorbed gas will flow out of the open-end 36 of the inner vessel 30 and 
through the passageways formed by the slots or grooves, 72, 74, 76 and the 
inner wall of the outer vessel 20 into the chamber 39 and then the valve 
16. The openings such as shown as 62, 64 and 66 in the disc 60 will 
provide pathways for the desorbed gas to flow through the layers of carbon 
out of the open-end 36 and up through the passage ways along the outer 
surface of the inner vessel 30. This will provide a flow path for the 
desorbed gas to contact the wall of the outer vessel 20 and as the 
desorbed gas travels through the passage ways to cause the heat contained 
in the food or beverage which is in contact with the outer surface 22 of 
the outer vessel 20 to be conducted away from the food or beverage and 
with the desorbed gas into the atmosphere. This will enhance the cooling 
effectiveness of the heat exchange unit. 
It will also be recognized that the intimate thermal contact between the 
walls of the inner and outer vessels and the discs causes the heat 
contained within the food or beverage to also be conducted internally of 
the heat exchange unit and into contact with the carbon particles. This 
heat transfer enhances the desorption process therefore releasing more 
carbon dioxide gas from the carbon particles. As the carbon dioxide gas is 
desorbed, it passes downwardly (FIG. 1) through the openings in the discs 
and out the open end of the inner vessel and upwardly to the chamber 39. 
There is thus provided a dual heat flow path thus increasing the 
effectiveness of the heat exchange unit.