U.S. patent application number 09/975729 was filed with the patent office on 2002-08-08 for heat transfer device.
Invention is credited to Curtiss, Richard, Paine, Lisa Jane, Riffat, Saffa Bashir.
Application Number | 20020104319 09/975729 |
Document ID | / |
Family ID | 26315799 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020104319 |
Kind Code |
A1 |
Paine, Lisa Jane ; et
al. |
August 8, 2002 |
Heat transfer device
Abstract
A self cooling can has water on a pre-wetted wick (478), in a
chamber and an adsorbent in another chamber communicable upon
actuation of the can with the chamber. One or both of the chambers
is at low pressure. Upon actuation the pressure of the wick drops,
water vapour is absorbed by the adsorbent from the internal
atmosphere and more water evaporates from the wick to replace it,
thereby causing a cooling effect in heat generated in the adsorbent
may be contained by but a take-up system, such as phase change
material or microcapsules of high heat capacity material such as
water.
Inventors: |
Paine, Lisa Jane;
(Leicestershire, GB) ; Riffat, Saffa Bashir;
(Nottingham, GB) ; Curtiss, Richard; (Chelmsford,
GB) |
Correspondence
Address: |
BAKER & BOTTS
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
|
Family ID: |
26315799 |
Appl. No.: |
09/975729 |
Filed: |
October 11, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09975729 |
Oct 11, 2001 |
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09492642 |
Jan 27, 2000 |
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6341491 |
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Current U.S.
Class: |
62/4 ; 62/480;
62/60 |
Current CPC
Class: |
F25B 17/08 20130101;
F25D 31/007 20130101; F25D 2331/805 20130101 |
Class at
Publication: |
62/4 ; 62/480;
62/60 |
International
Class: |
F25D 005/00; B65B
063/08; F25B 017/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 1999 |
GB |
9917570.5 |
Jan 25, 1999 |
GB |
PCT/GB99/00255 |
Claims
1. A self cooling beverage container having a beverage chamber
adapted to hold a beverage, an adsorbent, an evaporative
refrigerant, an isolator isolating said refrigerant from said
adsorbent and an actuator adapted in use to communicate said
adsorbent with said refrigerant so that, in use, said evaporative
refrigerant evaporates and is adsorbed by said adsorbent,
evaporation causing cooling of said beverage in use, a plurality of
heat take up bodies comprised of heat take up material being
provided in said body of adsorbent, said heat take up bodies each
having a surface area in contact with said adsorbent, which said
surface areas of said heat take up bodies are significantly larger
than the respective surface areas of spheres of equivalent
volume.
2. A self cooling beverage container according to claim 1 wherein
said heat take up means comprise a plurality of elongate looped
filaments.
3. A self cooling beverage container according to claim 2 wherein a
substantial number of said looped filaments are connected to a
common core.
4. A self cooling beverage container according to claim 3 wherein a
majority formation of said looped filaments are connected to a
common core at both ends of the loops.
5. A self cooling beverage container according to claim 1 wherein
said heat take up means comprise substantially flattened tapes.
6. A self cooling beverage container according to claim 1 wherein
said heat take up means comprise tubes.
7. A self cooling beverage container according to claim 6 wherein
said tubes contain a fluid, or a phase change material.
8. A self cooling beverage container according to claim 7 wherein
said tubes contain wax adapted to melt as said heat take up
material absorbs heat.
9. A self cooling beverage container according to claim 6 wherein
said tubes have a substantially helical shape.
10. A self cooling beverage container according to claim 1 wherein
said heat take up means are arranged as a plurality of
substantially flat and parallel plates.
11. A self cooling beverage container according to claim 1 wherein
said heat take up means are arranged as elongate capsules.
12. A self cooling beverage container according to claim 11 wherein
said capsules contain phase change material and have a retaining
layer surrounding said phase change material such that in use said
phase change material changes phase and is retained with said
retaining layer.
13. A self cooling beverage container according to claim 12 wherein
said retaining layer has a higher melting point than said phase
change material.
14. A self cooling beverage container according to claim 13 wherein
said phase change material comprises wax.
15. A self cooling beverage container according to claim 1 wherein
said heat take up means are arranged as a plurality of filaments
each having a first end connected to a common core and a second end
which extends into said adsorbent.
16. A self cooling beverage container having a beverage chamber
adapted to hold a beverage; an adsorbent; an evaporative
refrigerant; an isolator isolating said refrigerant from said
adsorbent; an actuator adapted in use to communicate said adsorbent
with said refrigerant so that, in use, said evaporative refrigerant
evaporates and is adsorbed by said adsorbent evaporation causing
cooling of said beverage in use; and a pre-wetted wick; said
prewetted wick wetted before activation of the device with said
evaporative refrigerant, and said wick being adapted to hold an
amount of said evaporative refrigerant close to said beverage
container, and wherein said wick is provided with apertures.
17. A self cooling beverage container according to claim 16 wherein
said wick has a first surface spaced from a second surface by a
body of material of said wick; said body of material of said wick
having a wicking porous or voided structure adapted to enable said
evaporative refrigerant to be wicked, in use, along said wick and
where said apertures extend through said body of material from said
first surface towards said second surface; said apertures being of
a size such that the smallest cross-sectional dimension across said
aperture is significantly bigger than an average pore or void
dimension, thereby rendering said apertures less likely to block
with solid, frozen, refrigerant in use than said pores or
voids.
18. A self cooling beverage according to claim 16 wherein said wick
has a first surface spaced from a second surface by a body of
wicking material, and holes or recesses are provided in said wick
extending from at least one of said surfaces.
19. A self cooling beverage according to claim 18 wherein said
holes or recesses comprise at least some through-holes or recesses
extending from said first surface to said second surface.
20. A self cooling beverage container having a beverage chamber
adapted to hold a beverage, an adsorbent body comprising adsorbent
material, an evaporative refrigerant, an isolator isolating said
evaporative refrigerant from said adsorbent body and an actuator
adapted in use to communicate said adsorbent body with said
evaporative refrigerant such that, in use said evaporative
refrigerant evaporates and is adsorbed by said adsorbent material,
evaporation causing cooling, in use; and wherein said adsorbent
body is shaped so as to form channels within said adsorbent body so
as to, in use, expose evaporated evaporative refrigerant to parts
of said adsorbent body that otherwise said evaporative refrigerant
would not reach if said adsorbent body were an unchannelled block
of adsorbent material.
21. A self cooling beverage container according to claim 1 being
further provided with a pre-wetted wick; said prewetted wick wetted
before activation of the device with said evaporative refrigerant,
and said wick being adapted to hold an amount of said evaporative
refrigerant close to said beverage container, and wherein said wick
is provided with apertures.
22. A self cooling beverage container according to claim 21 wherein
said wick has a first surface spaced from a second surface by a
body of material of said wick; said body of material of said wick
having a wicking porous or voided structure adapted to enable said
evaporative refrigerant to be wicked, in use, along said wick and
where said apertures extend through said body of material from said
first surface towards said second surface; said apertures being of
a size such that the smallest cross-sectional dimension across said
aperture is significantly bigger than an average pore or void
dimension, thereby rendering said apertures less likely to block
with solid, frozen, refrigerant in use than said pores or
voids.
23. A self cooling beverage container according to claim 21 wherein
said wick has a first surface spaced from a second surface by a
body of wicking material, and holes or recesses are provided in
said wick extending from at least one of said surfaces.
24. A self cooling beverage container according to claim 23 wherein
said holes or recesses comprise at least some through-holes or
recesses extending from said first surface to said second
surface.
25. A self cooling beverage container according to claim 1 wherein
said adsorbent comprises an adsorbent body comprising adsorbent
material, said adsorbent body is shaped so as to form channels
within said adsorbent body so as to, in use, expose evaporated
refrigerant to parts of said adsorbent body that otherwise said
evaporative refrigerant would not reach if said adsorbent body were
an unchannelled block of adsorbent material.
Description
[0001] This invention relates to heat transfer devices. In
particular, but not exclusively, this invention relates to heat
transfer devices for heating or cooling edible or drinkable
materials.
[0002] The development of efficient and "environmentally-friendly"
technologies for cooling drink and food products has been sought
after. The trend towards more leisure time being spent in locations
away from home is on the increase as the range and availability of
outdoor entertainments and pastimes increases.
[0003] Advances have been made in developing cooling devices,
including cold boxes, thermoelectric picnic coolers and portable
chilling units. However, these units have the disadvantages of
being bulky and expensive. One device, known as the "chill can" has
been subjected to International restrictions owing to environmental
concerns over its use. Furthermore, little attention has been paid
to the development of heating devices for heating drinks and food
products.
[0004] A lot of work has already been done in the area of
self-cooling cans/self-heating cans (or other containers). In order
to understand fully the remainder of this application the reader is
now directed to read PCT/GB99/00255 (the contents of which are
hereby incorporated into this application by reference), and to
read: U.S. Pat. Nos. 4,978,495, 5,168,708, 736,599, WO 9 202 770,
U.S. Pat. No. 4,771,607, 4,752,310, EP 0 726 433, U.S. Pat. No.
4,126,016, 5,088,302, 5,083,607, and 5,054,544, and our own earlier
patent applications GB 2 329 461, GB 2 329 392, GB 2 329 459 and GB
2 333 586. Reading these documents, especially our own patent
applications and PCT/GB99/00255, will assist in determining the
full disclosure of the text and drawings that follow.
[0005] According to one aspect of the invention there is provided a
heat transfer device containing a refrigerant, and said device
further including operative means for allowing transfer of the
refrigerant from a first region of the device to a second region of
the device and means to drive said transfer of the refrigerant,
thereby transferring heat from said first region to said second
region, such that heat can be transferred to or from a material to
be heated or cooled.
[0006] Preferably, the transfer of said refrigerant occurs by
evaporation of the refrigerant. However, any other change of phase
of a material may be used. For example sublimation of a solid to a
gas may be used. The use of a phase change is advantageous because
of the heat that must be absorbed to achieve this phase change.
[0007] Desirably, the means to drive said transfer of the
refrigerant comprises a refrigerant take up agent to take up said
refrigerant. Thus, heat can be extracted from the material by
transfer of the refrigerant and heat is given out by the take up
agent when the refrigerant is taken up thereby. The take up agent
may be in the form of an adsorbent or absorbent.
[0008] According to another aspect of this invention there is
provided a heat transfer device containing a refrigerant and a
refrigerant take up agent, and said device further including
operative means for allowing evaporation of the refrigerant,
whereby the take up agent takes up said evaporated refrigerant such
that heat absorbed on evaporation of the refrigerant is evolved at
the take up agent to enable heat to be transferred to or from a
material to be heated or cooled.
[0009] Advantageously, the device is of a suitable size to be
inserted in, or arranged in, or installed, or arranged around, a
vessel suitable for holding a beverage or a foodstuff. Examples of
such a vessel include beverage cans, bottles, cups, kegs, casks,
and the like.
[0010] Preferably, the taking up of the refrigerant occurs at a
first region of the device and evaporation of the refrigerant by
the take up agent occurs at a second region.
[0011] The take up agent may be an adsorbent or an absorbent. Thus,
heat of adsorption or absorption is given out when the evaporated
refrigerant is adsorbed onto the adsorbent or absorbed by the
absorbent and the heating or cooling of the material is
enhanced.
[0012] Desirably, the device comprises a first part for the take up
agent and a second part for the refrigerant. The first part is
preferably at a lower pressure than the second part before the
operative means is operated. An advantage of having the lower
pressure in the first part is that evaporation of the refrigerant
is enhanced once the pressures have been allowed to equalise.
[0013] In one embodiment, the second part may be at ambient
pressure and the first part may be evacuated. In another
embodiment, the second portion may be at above ambient pressure and
the first part may be at ambient pressure. Alternatively, both the
first and second parts are evacuated.
[0014] The skilled person will appreciate that the rate of
evaporation is affected by the physical conditions surrounding the
system in which evaporation is occurring. That is the pressure,
temperature, temperature gradients, etc. will all affect the
evaporation rate. Providing a low pressure environment may be
advantageous because of a consequent reduction in the temperature
at which evaporation of the refrigerant occurs.
[0015] In one embodiment the refrigerant may be water and the
pressures in the first and second parts (once the operative means
has allowed evaporation of the refrigerant) may be such that the
water boils at substantially room temperature. Such a structure is
clearly advantageous because boiling of the water will increase the
rate of evaporation of the refrigerant which will speed the rate of
cooling or heating of the material.
[0016] The first and second parts are advantageously isolated from
each other, providing a structure in which the pressures can be
maintained before activation of the operative means.
[0017] The operative means may be adapted to provide communication
between the first and second parts on operation thereof. The first
and second parts may be permanently attached to each other, for
example they may be integral with each other. Alternatively, the
first and second parts may be initially separate from each other to
be attached together to allow communication therebetween on
operation of the operative means.
[0018] The device may comprise a first element, which may be in the
form of a first wall, on which the take up agent can be arranged,
and a second element, which may be in the form of a second wall, to
provide dispersion of the refrigerant.
[0019] The first element may be substantially cylindrical in shape,
but it may be of any other suitable shape. The second element may
be cylindrical in shape and dispersal means may be provided on said
second element to disperse the refrigerant around the second
element.
[0020] The dispersal means may comprise wicking means. The first
and second elements are desirably spaced from each other to allow
heat transfer from one to the other.
[0021] In one embodiment, the first part includes the second
element and the second part may be in the form of a container
adapted to release refrigerant into the second element on operation
of the operative means.
[0022] In another embodiment, the second part may comprise the
second element.
[0023] The operative means may comprise a release member adapted to
provide an aperture in the second part to release said refrigerant
or it may comprise an elongate rod having at one end thereof a
substantially cylindrical member (the elongate rod and the
cylindrical member may be thought of as a release means).
[0024] A membrane may be provided between the first and second
parts to isolate the first part from the second part. The membrane
may be formed of a metallic foil, for example aluminium foil.
Alternatively, the membrane may be formed from a plastics material.
Indeed, the membrane may be formed from any material which is
compatible with the materials of the device.
[0025] A membrane compromising means (which may be the same as the
release member) may be provided, adapted to pierce, rupture, cut or
otherwise compromise said membrane so connecting said first and
second parts. The operative means may comprise the membrane
compromising means.
[0026] The skilled person will appreciate that the membrane
compromising means should be adapted to allow communication between
the first and second parts and that should the membrane
compromising means simply pierce the membrane the membrane may
still substantially provide a seal between the first and second
parts i.e. perhaps sealing to the membrane compromising means.
Therefore, the membrane piercing means may be adapted, in use, to
retract slightly after compromising the membrane. This retraction
may be provided by way of a cam or other similar structure.
Alternatively, or additionally, the membrane compromising means may
comprise a vent means, which may be duct, or hole, etc. to allow
communication between the first and second parts once the membrane
has been compromised.
[0027] The cylindrical member preferably has an open end arranged
adjacent the membrane, whereby operation of the operative means
pushes the open end of the cylindrical member into engagement with
the membrane and pierces the membrane.
[0028] The release member may be in the form of a spike or pin to
pierce the second part.
[0029] The second part may be formed of a suitable plastics
material, and may be in the form of a bubble.
[0030] Where the device is to be used to cool the material, the
second element is advantageously adapted to be arranged adjacent,
or in contact with said material, and the first element is arranged
such that heat transfer thereto can be dissipated to the
atmosphere.
[0031] Where the device is to be used to heat the material, the
first element is advantageously adapted to be arranged adjacent, or
in contact with, said material and the second element is arranged
such that heat can be extracted from the atmosphere to be
transferred to the first element thereby heating said material.
[0032] Preferably, at least the first part is in the form of a tube
or pipe, although both first and second parts may be generally in
the form generally of a tube or pipe. The first part or both first
and second parts may be in the form of an elongate tube, wherein
the first part constitutes a first portion of the tube and the
second part constitutes a second portion of the tube. The skilled
person will appreciate that the tube or pipe is intended to cover
embodiments wherein the cross section is not circular and is for
example square, triangular, elliptical, etc.
[0033] In one embodiment, the first part constitutes a double skin
of a vessel holding the material to be heated or cooled, the double
skin comprising inner and outer walls.
[0034] In another embodiment, the device is in the form of a sleeve
having said inner and outer walls, the said sleeve being adapted to
receive a vessel, for example a bottle or a can to be heated or
cooled. Preferably, where the material is to be heated, the inner
wall comprises said first element and the outer wall comprises said
second element. Preferably, where the material is to be cooled, the
outer wall comprises the first element and the inner wall comprises
the second element.
[0035] In a further embodiment, the device is configured to be
arranged inside a vessel for heating or cooling the material
therein. The device may be manufactured separately to be inserted
in the vessel when desired, or may be arranged in the vessel during
manufacture.
[0036] A wicking means may be provided to assist the evaporation or
movement of said refrigerant. A wicking means is advantageous
because it increases the surface area from which the refrigerant
can evaporate thus speeding the heat transfer process. Preferably
the wicking means is pre-wetted with refrigerant prior to the
operation of the operative means. Pre-wetting is advantageous
because it increases the rate at which evaporation initially
occurs, thus again increasing the heat transfer rate.
[0037] Pre-wetting (wetting of the wick prior to actuation of the
device) is further advantageous because it should evenly distribute
the refrigerant on the wick and removes the need for the
refrigerant to wet the wick. Such wetting of refrigerant through
the wick may slow the cooling process.
[0038] Preferably the material from which the wicking means is
fabricated readily gives up the vapour phase of the refrigerant
whilst maintaining the liquid phase within. This is advantageous
because it allows the refrigerant to remain in the wicking means
(if it is pre-wetted) before operation of the operative means but
allows the refrigerant to evaporate readily. Using a material which
holds onto the liquid phase is advantageous in circumstances
wherein the device is tipped before operation which is clearly a
possibility during transport of the device.
[0039] The wicking means can be made, for example, of metallic mesh
(e.g. copper mesh or stainless steel mesh), or of a sintered powder
(e.g. sintered copper or P.T.F.E.), tissue paper, plastic foam, or
paper fibre.
[0040] Alternatively, the wicking means may be formed of a porous
fabric, for example cloths sold under the trade mark JCloth or
similar. The fabric is preferably perforated to define at least one
aperture, and desirably a plurality of apertures therethrough which
may serve to prevent or reduce the formation of ice on the
fabric/wick.
[0041] The apertures may provide alternate pathways for liquid in
the wick which resist being blocked with ice to a greater extent
then the porous body of the wick. Alternatively, the apertures may
form sites at which ice forms to a greater extent than on the
porous body of the wick such that ice does not stop evaporation
from said porous body of the wick.
[0042] In yet further embodiments, the wicking means may be
provided from materials such a shammy (which may be real or
synthetic), hyrophillic gels or granules (which may be such as
water retaining gels used in horticulture), micro-fibre type
materials, or Pertex.TM..
[0043] Localised freezing may occur which is caused by the cooling
process being too efficient at localised points in the device.
Freezing of the refrigerant is disadvantageous because it restricts
further evaporation of the refrigerant and means that additional
energy is required to melt the ice which reduces the efficiency.
Pre-wetting of the wick may be advantageous because it increases
the surface area over which the refrigerant evaporates which may
prevent such localised freezing from occurring (if the evaporation
occurs over a larger area the localised rates of cooling may be
less). Further, the pre-wetting may ensure that evaporation occurs
over the whole surface area of the wick. If the refrigerant is left
to wet up the wick, initially evaporation will only occur from
portions of the wick.
[0044] The wicking means may be corrugated, or other wise
contoured. Such a structure is advantageous because it maximises
the surface area of the wicking means and increases the
advantageous effects.
[0045] In another embodiment, the second part constitutes a double
skin of a vessel holding the material to be cooled, the double skin
comprising inner and outer walls.
[0046] Preferably, the inner wall is provided with the wicking
means which preferably substantially covers the inner wall. Again,
the wicking means is advantageously wetted prior to use of the
device.
[0047] In a further embodiment, the first part is arranged on the
second part.
[0048] The first part may be in the form of a first tube and the
second part may be in the form of a second tube.
[0049] The first or second part may be receivable in the material
and may further include one or more heat exchange members adapted
to extend into the material to enhance the transfer of heat.
Enhancing the heat transfer is advantageous because it speeds the
heating or cooling process.
[0050] The heat exchange member(s) may comprise a plurality of fins
which are preferably in the form of wire loops. Both of these
structures providing simple yet efficient heat transfer.
[0051] Further heat exchange members may extend in the second part,
which may comprise a plurality of fins preferably in the form of
wire loops.
[0052] Heat absorption means may be provided in association with
the take up agent. Such an absorption means is advantageous because
it may promote further take up of the refrigerant because the take
up agent may be maintained at a lower temperature. A lower
temperature of the take up agent may not only increase the rate of
heating or cooling of the material but may also reduce make the
device more pleasant to hold and perhaps safer as well.
[0053] The surface area of the heat take up means may be enlarged
with respect to the amount of the heat take up means. By enlarged
in this case we may mean having a greater surface area than a
sphere of the same mass and material, by a factor in the region of
10%, 20%, 50%, 100%, 200% or possibly more.
[0054] Alternatively, the heat absorption means may also comprise
pockets of a material which is adapted to change phase (a phase
change material) as heat is absorbed. The skilled person will
appreciate that a phase change requires an enthalpy change which in
turn requires a heat input. Such a phase change is therefore
advantageous because of the increased amount of heat absorbed from
the take up agent. The phase change material may change from solid
to liquid, from liquid to vapour or possibly from solid to
vapour.
[0055] The heat absorbing means may be moulded into the take up
agent. Indeed a mixture of heat take up material and adsorbent may
be formed (e.g. moulded) into a cake or body.
[0056] The heat take up means may comprise a plurality of elongate
looped filaments. A majority of said filaments may be connected to
a common core. The filaments may have a cross section with a
greatest dimension in the plane of the cross section and the loops
may have a greatest dimension in the plane of the loop. By elongate
we may mean having the greatest dimension of the loop in the region
of 2, 3, 5, 10, 100 or more times the greatest dimension of the
cross section.
[0057] The heat take up means may comprise substantially flattened
tapes. By substantially flattened tapes we may mean tapes having a
width and a thickness where said width is at least twice said
thickness.
[0058] The heat take up means may also comprise a hollow tube
extending through the take up agent. The tube may contain a fluid,
which may be a liquid. Filling the tube with a liquid is
advantageous because of the high heat capacity of the liquids which
will increase the amount of heat which can be absorbed from the
take up agent, thereby increasing the rate of heating or cooling of
the material.
[0059] Water may be used to fill the tube, providing a cheap
material with a high thermal mass.
[0060] The tube may be formed into a convoluted shape, such as a
helix, thereby increasing the length of tube (and therefore the
heat capacity) which can be fitted within the take up agent. The
skilled person will appreciate that it is important for the heat
absorption means to have a large surface area to increase the rate
at which heat can be absorbed.
[0061] Conveniently the tube is fabricated from a material with a
high heat conductivity. The tube may be fabricated from a metal.
This structure is advantageous because it increases the amount of
heat that can be absorbed by the tube.
[0062] The heat take up means may be arranged as a plurality of
substantially flat and parallel plates.
[0063] The heat take up means may comprise elongate capsules. By
this we may mean capsules having a maximum diameter is at least
twice the minimum diameter.
[0064] The capsules may contain a phase change material or may
contain a material with a high heat capacity, perhaps water, oil,
or air. They may have a wall of a first material and a centre of a
different material, which may change phase with temperature over
the operating temperature of the device (e.g. plastics, or other
material, capsules may surround a wax centre which may melt,
absorbing energy, in use). The capsule may have a high thermal
conductivity wall, for example a metal wall, or metal foil.
Alternatively, there may be no containment wall for the melted
phase change material, which when melted may be permitted to
contact the adsorbent directly. The capsule wall may have a higher
melting point than that of the interior.
[0065] The heat absorption means may comprise pockets of air.
[0066] The heat take up means may comprise a plurality of
filaments, each having a first end connected to a core to which a
plurality of said filaments are connected and a second end with
extends into the absorbent.
[0067] Insulation means may be provided. The insulation means may
insulate the first part, or the second part or perhaps both of the
first and second parts.
[0068] The skilled person will appreciate that insulation on the
first part (around the take up agent) may be adapted to prevent
heat given off from the take up agent from heating any of the
refrigerant, the atmosphere or the material. If the device is
adapted to cool the material then it is clearly disadvantageous for
heat from the take up agent to reach the material. Further, it is
clearly disadvantageous for the device to become too hot and it is
desirable to provide insulation to prevent this from occurring. The
insulation may be required to prevent significant, rapid, heat
transfer, rather than completely block heat transfer. For example,
it is envisaged that a can of self-chilled beverage would be drunk
by the consumer in, say, 15 minutes after opening, or 20 minutes
(or perhaps 30 minutes). After, next say 10 minutes or 15 minutes
(a period) it may not matter to the consumer too much if the
beverage begins to warm up due to heat transfer from the
adsorbent--they have by then had a first cold draught from the can,
and the can is in any event absorbing heat from the external
environment. Thus a "firewall" delay of heat transfer from the
adsorbent may be enough.
[0069] Further, it will be appreciated that insulation on the
second part (around the refrigerant) may be adapted to prevent heat
from reaching the refrigerant from the atmosphere, the material or
the take up agent. If the device is adapted to heat the material
then it is clearly disadvantageous for heat to be absorbed by the
refrigerant from the material. Insulation may be provided around
the second part to ensure that heat is not absorbed from the
atmosphere by the refrigerant: if the material is to be cooled then
it is advantageous that heat is absorbed from the material rather
than from the surroundings.
[0070] One of said first and second elements may surround the other
of said first and second elements. The other of said first and
second element can preferably be arranged in a material to be
heated or cooled.
[0071] In one embodiment, the first element is in the form of a
first tube surrounding the second element, which is preferably in
the form of a second tube. The second element is desirably adapted
to be arranged in a material to be cooled.
[0072] A conduit arrangement may extend between the first and
second elements to conduct the evaporated refrigerant, thereby
transferring heat from the second element to the first element.
When the device is to be used to cool the material, the first
element surrounds the second element and, when the device is to be
used to heat the material, the second element surrounds the first
element.
[0073] Heat exchange members may extend from the first or second
element into the material to be heated or cooled.
[0074] The first and second elements may comprise first and second
tubes initially separate from each other and adapted to be
connected in communication for heating or cooling. The first and
second elements may be connected by the operative means.
[0075] The second part may comprise a container connected to the
first part.
[0076] The operative means may comprise a valve between the first
and second parts. The valve is preferably movable to an open
position to allow the first and second parts to communicate with
each other.
[0077] Heat absorption means may be arranged adjacent one of the
first or second elements. Where the device is to be used to cool
the material, the heat absorption means may be arranged in thermal
contact with the first element to absorb heat given out by the take
up agent. The heat so absorbed by the heat absorption means may be
given off to the atmosphere.
[0078] Where the device is to be used to heat the material, the
heat absorption means may be arranged in thermal contact with the
second element, whereby heat absorbed by the heat absorption means
can be desorbed via the second element to evaporate refrigerant in
the first part.
[0079] In one embodiment, the heat absorption means is provided in
a chamber which may be defined at least partially by the first or
second element. Preferably, the chamber surrounds, or is surrounded
by, said first part.
[0080] In one embodiment, the chamber is in the form of a
substantially cylindrical tube defined substantially wholly by said
first or second element internally of the first part. The skilled
person will appreciate that the chamber could have any other cross
section and is not necessarily cylindrical.
[0081] In another embodiment, the chamber is in the form of a
sleeve defined partially by the first or second element externally
of said first part. The sleeve is conveniently defined between said
first or second element and an external wall.
[0082] In one embodiment, the heat absorption means comprises a
refrigerant adapted to evaporate when heat is absorbed thereby.
Valve means may also be provided to release to the atmosphere
evaporated refrigerant from the heat absorption means. The valve
means is particularly suitable where the device is to be used for
cooling the material.
[0083] In another embodiment, the heat absorption means may be a
phase change material adapted to change phase from solid to liquid
or from solid to vapour on absorption of heat. Where the phase
change material changes from solid to vapour, valve means may be
provided to release the vapour to the atmosphere. The use of valve
means is particularly suitable where the device is to be used in
cooling the material.
[0084] In a further embodiment, the heat absorption means may be a
heat pipe preferably having one end region in thermal contact with
the first part and the opposite end region outside the first part.
The end region of the heat pipe external of said first part may be
provided with fin means to assist in heat transfer to or from the
heat pipe. In this embodiment, said one end region is preferably
surrounded by the first part.
[0085] In another embodiment, the device may comprise at least one
heat pipe, and preferably a plurality of heat pipes extending from
the second part into the material. The, or each, heat pipe is
preferably in the form of a needle heat pipe. In this embodiment, a
valve is provided between the second part and the first part,
whereby when the valve is opened, refrigerant in the second part is
evaporated to be taken up by the take up agent in the first part,
and the evaporation of the refrigerant causes heat to be
transferred from the material along the heat pipes to an end region
of the or each heat pipe in the first part, thereby cooling the
material. In this embodiment, the first part is arranged outside
the vessel containing the material, and the second part is arranged
inside the vessel. Alternatively, where heating is required, the
second part may be arranged outside the vessel, and heat pipes may
extend from the first part inside the vessel whereby when the valve
is opened, evaporating refrigerant is taken up by the take up agent
and heat dissipated by the, or each, heat pipe into the
material.
[0086] The above embodiments are particularly suitable for use with
a take up agent in the form of an adsorbent.
[0087] In a further embodiment, where the take up agent comprises
an absorbent, the device may be provided with a third part
initially containing the absorbent. The third part may be provided
with release means, whereby when the release means is activated,
absorbent is released into the second portion. In this embodiment,
when the operative means for the second part is operated, the
refrigerant is released into the first part to be evaporated
therein and absorbed by the absorbent thereby releasing heat. The
third part may be a further bubble, and the operative means may be
suitable for piercing the bubble, or otherwise forming an aperture
in said further bubble.
[0088] A material mixing means may be provided adapted to ensure
that the material is mixed. The skilled person will appreciate that
the cooling/heating process relies on temperature differences.
Unless the material is mixed temperature gradients may occur in the
material which slows the cooling or heating process. Therefore,
mixing the material is advantageous because it can help to prevent
the occurrence of such gradients and can help to increase the rate
at which the material is heated or cooled. The skilled person will
appreciate that the rate of heating/cooling should be higher if
there is more of a temperature difference. Therefore, if
temperature gradients exist within the material (for instance
cooler toward an outside region and hotter toward a central region)
then the rate of cooling/heating may be reduced because the
temperature difference between the material and the first or second
part is reduced. Therefore, removing temperature gradients within
the material is beneficial because it may increase the rate of
cooling or heating.
[0089] The material mixing means may comprise a disk or other body
provided within the material. This is especially advantageous when
the material is a liquid.
[0090] Preferably the disk/body is perforated. The disk/body may be
adapted, in use, to move through the material, thus providing a
mixing action. The device may be adapted to be inverted to cause
the disk/body to move through the material under the influence of
gravity. Such a structure is simple yet effective in providing a
mixing action. Alternatively a manually operated mixing/circulating
mechanism may be provided, for example a finger-operated pump or
paddle.
[0091] Of course, the skilled person will appreciate that any means
that mixes the material will prevent temperature gradients from
forming. Pumps, vanes, stirring means may all be provided to
prevent temperature gradients from occurring.
[0092] In one embodiment, the device may comprise a pipe (or a
linked plurality of pipes).
[0093] Preferably, a device according to this embodiment comprises
an elongate pipe having a first portion to containing the adsorbent
or absorbent, a second portion initially separated from said first
portion and adapted to contain the refrigerant, and communication
means between said first and second portions, whereby operation of
said communication means causes the refrigerant to be adsorbed or
absorbed by the adsorbent or absorbent, with evolution of heat from
the first portion of the device and corresponding absorption of
heat at the second portion of the device.
[0094] The second portion (to contain the refrigerant) is generally
integral with the elongate pipe. The second portion may be adapted
to contain the refrigerant either under sub-ambient or under
super-ambient pressure, I.e. under vacuum or under pressure
respectively, relative to ambient pressure.
[0095] The second portion may contain the refrigerant under
permanent sub-ambient or super-ambient pressure.
[0096] Alternatively, means, such as a pump, may be provided to
produce a sub-ambient or super-ambient pressure in the first
portion when required. Means may also be provided to purge air from
the first portion, thereby increasing the efficiency of the
device.
[0097] The first portion (to contain the adsorbent or absorbent)
may likewise be integral with the elongate pipe.
[0098] Alternatively, the first portion may be initially discrete
relative to the second portion and adapted to be connected thereto.
Such connection may preferably include operating means for causing
communication between the first and second portions of the elongate
pipe.
[0099] The communication means may, for example, comprise one or
more valves (such as one-way or throttle valves). Alternatively,
the communication means may comprise a three-way (or ejector)
valve.
[0100] In another embodiment, the heat-transfer device may comprise
a pipe (or a linked plurality of pipes).
[0101] In a further embodiment, the device comprises an elongate
pipe in which the refrigerant and the adsorbent or absorbent are
combined and under super ambient pressure within the pipe. In this
embodiment, the adsorption or absorption of the refrigerant by the
adsorbent or absorbent, with consequent cooling and heating
respectively, is achieved by the release of the super-ambient
pressure by means of a valve or the like provided in operative
association with the elongate pipe.
[0102] In yet another embodiment, the refrigerant is contained,
under sub-ambient pressure, in an outer skin of a vessel containing
a liquid such as a soft drink) to be cooled. A valve is provided in
the skin for the release of the vacuum and the valve is operable by
means including a container for the adsorbent.
[0103] The device according to the present invention, may be
permanently fixed inside a vessel to contain a liquid to be cooled
or heated.
[0104] Alternatively, such a device may be provided as a "portable"
or "pocket" device, to be placed in an opened container (such as a
can of beer to be cooled or a can of soup to be heated) when
required.
[0105] Devices according to the present invention may be operated
by producing communication between the refrigerant and the
adsorbent or absorbent (generally by actuating a valve). The
provision of the communication causes the refrigerant to volatilise
and to interact with the adsorbent or absorbent. As a result of
that interaction, heat is evolved from the adsorbent or absorbent
and heat is correspondingly absorbed from the surroundings of the
refrigerant.
[0106] In one instance, where a device according to the present
invention is placed in, say, a can of beer, with the portion
containing the adsorbent or absorbent being outside the can and the
portion containing the refrigerant material being inside the can,
interaction between the refrigerant and the adsorbent or absorbent
causes the evolution of heat to the atmosphere and absorption of
heat from the beer within the can leading to cooling.
[0107] In a second instance, where the device is placed in, say, a
can of soup, with the portion containing the adsorbent or absorbent
being inside the can, interaction between the refrigerant and the
adsorbent or absorbent again causes evolution of heat from the
adsorbent, but the heat evolved is used to heat the soup within the
can instead of being vented to the atmosphere.
[0108] Operation of the valve may be achieved by means external to
the device (as, for example, where a pump or the like is
operatively associated with the elongate pipe or the adsorbent
material is contained in a discrete "plug-in" member).
Alternatively, the valve may be actuated by means of the internal
pressure of the contents of a vessel (as, for example, a can of
drinkable liquid to be cooled or heated by means of a device
according to the present invention).
[0109] Refrigerants suitable for use with a present invention
preferably include the following:
[0110] Water, alcohols (e.g. methanol, ethanol), haloalcohols (e.g.
triflerethanol), haloalkanes (e.g. trifluoro-ethane), alkanes (e.g.
C.sub.3 to C.sub.6), ammonia, carbon dioxide, aromatic hydrocarbons
(e.g. benzene, toluene, aniline), acetophenone, butyl acetate,
butyric acid, cellulose acetate, cresol, cumene, cyclohexanol,
cyclohexanone, dibutylphtalate, diethanolamine, diethylsulphate,
dimethylformamide, dimethylhydrazine, dimethylphtalate, ethylene
glycol, hydrazine, methylhydrazine, methylpyrrolidinone,
naphthalene, styrene, sulfolane, tetrachloroethylene,
trichloroethylene, undecane.
[0111] In the preferred embodiment the refrigerant may be water.
Water is advantageous because it is cheap and readily available and
is also nontoxic. Clearly, when the device is being used in
conjunction with foodstuffs it is desirable that there is no chance
of contamination of the foodstuff occurring.
[0112] The skilled person will appreciate that a mixture of a first
substance and a second substance will have a different boiling
point to a sample of substantially pure first substance. In some
embodiments the refrigerant may be a mixture adapted to reduce the
boiling point of the refrigerant. For instance, the refrigerant may
be a mixture of water and alcohol.
[0113] Take up agents suitable for use with the present invention
preferably include the following:
[0114] silica gel, activated alumina, zeolites (molecular sieves),
activated charcoal, alkanes (e.g. C.sub.3 to C.sub.6), alcohols
(e.g. methanol, ethanol), amides (e.g. N, N-dimethyl acetamide),
ketones/lactams (e.g. N-methyl pyrrolidone), carboxylic acid salts
(e.g. potassium formate), esters, alkali metal salts (e.g. lithium
bromide, lithium nitrate).
[0115] Thus, the refrigerant may be a volatile liquid or a gas, and
the take up agent may be a solid or a liquid.
[0116] Suitable combinations of refrigerant/take up agent for use
with the present invention preferably include the following:
[0117] water/zeolites-activated carbon, ethyl alcohol/silica gel,
water/silica gel, water/activated alumina, carbon dioxide/activated
alumina, water/zeolites 4A, 5A, 13X, ammonia/zeolites 4A, 5A, 13X,
carbon dioxide/zeolites 4A, 5A, 13X, ethene/activated carbon,
ammonia/activated carbon, water/activated carbon, methyl
alcohol/activated carbon, water/polymers, ammonia or water/metal in
organic salts (e.g. water/CaCl.sub.2, ammonia CaCl.sub.2
hydrogen/LaNi.sub.4, hydrogen/FeTi, water/potassium formate),
hydrofluorocarbons (HFC) refrigerant/adsorbent combinations (e.g.
R134a/activated carbon), fluid mixtures (e.g. water,
methanol/activated carbon, water/ammonia, ammonia (or carbon
dioxide/potassium formate, water/lithium bromide,
N-methylpyrrolidinone/t- rifluorethanol, dithioglycol (DTG)
/tetrafluorethane, water/ammonia-lithium nitrate, carbon
dioxide/N,N-dimethylacetamide, H.sub.2O/CaO.
[0118] It is desirable to increase the surface area of the
adsorbent/absorbent as much as possible to increase the rate at
which the adsorbent/absorbent can take up the refrigerant. This can
be achieved by the following means, for example coating the surface
with the adsorbent/absorbent (e.g. by using a binder or growing
adsorbent/absorbent on the surface) using adsorbent/absorbent
membranes (e.g. growing zeolites on a mesh) using an
adsorbent/absorbent cloth (e.g. activated carbon), providing
channels within the adsorbent/absorbent (or take up agent),
providing the take up agent as a powder or as pellets.
[0119] Suitable phase change materials that can be used with the
present invention preferably include the following: Glycerol, oils,
coconut/butter, paraffin wax, glauber salt
(Na.sub.2SO.sub.4.10H.sub.2O, butyl phenol, methanol, pentane,
ethane.
[0120] In most circumstances, the take up agent can be regenerated
once adsorption has occurred. Regeneration may be achieved by
heating the adsorbent (for example by means of a Peltier or like
device) or by means of an integral compressor provided in
association with the device.
[0121] The present invention further provides a method for heating
or cooling the contents of an enclosed vessel, in which one or more
heat transfer devices of the type hereinbefore described are placed
in contact with the contents of the vessel and each said device is
caused to transfer heat by means of an adsorption-based process
between a refrigerant material and an adsorbent material, whereby
heat is respectively liberated into or absorbed from the contents
of the vessel.
[0122] Thus, a method according to the present invention can be
applied to the heating of soup, tea or the like in an enclosed
vessel
[0123] Alternatively, the method can be applied to the cooling of
beer, soft drinks or the like in an enclosed vessel.
[0124] According to another aspect of the present invention there
is provided a heat-transfer device comprising an elongate,
generally tubular member adapted to contain a refrigerant and an
adsorbent or absorbent, together with means to cause the
refrigerant to be adsorbed by the adsorbent, whereby heat is
evolved from the adsorbent or absorbent and absorbed by the
refrigerant material.
[0125] According to another aspect of this invention there is
provided an assembly comprising a vessel for holding a material to
be cooled or heated and a heat transfer device as described above
arranged in thermal contact with the material.
[0126] According to another aspect of the invention comprises a
self cooling beverage container having a beverage chamber adapted
to hold a beverage, an adsorbent, an evaporative refrigerant, an
isolator isolating the refrigerant from the adsorbent, and an
actuator adapted in use to communicate the adsorbent with the
refrigerant so that, in use, the evaporative refrigerant evaporates
and is adsorbed by the adsorbent, evaporation causing cooling of
the beverage in use.
[0127] Preferably the adsorbent comprises activated carbon and the
refrigerant comprises water. The heat take up material may be
provided associated with the adsorbent, the heat take up material
comprising at least one of i) phase change material or ii) heat
exchange members comprising wire loops or wire bushes; or iii)
liquid-cooled surfaces provided in a body of the adsorbent.
[0128] A pre-wetted wick, wetted before activation of the device,
may be provided, the wick being wetted with the refrigerant and the
relationship between the refrigerant and wick being such that when
activated the refrigerant evaporates from the wick but before
activation the wick holds the refrigerant such that the liquid
refrigerant does not seep under gravity to leave a wick having dry
areas, irrespective of the orientation of the container during
storage or prior to use. The relationship between the wick and
refrigerant is preferably such that the wick is substantially
saturated with refrigerant, and remains so over substantially the
whole evaporative surface prior to use of the device, irrespective
of the orientation of the container during pre-use storage. A
refrigerant reservoir may be provided, refrigerant in the reservoir
replacing refrigerant in the wick as refrigerant in the wick
evaporates in use.
[0129] Beverage mixing means may be provided adapted to ensure that
the beverage to be cooled is mixed or made turbulent during cooling
of the beverage. Said beverage mixing means may comprise a gravity
moved member adapted to move through the beverage under the
influence of gravity. The member may comprise a sliding body
provided with through-holes. The beverage mixing means may comprise
a so-called "widget", adapted to generate a head on the
beverage.
[0130] The heat take up material comprises a tube, capsule or other
closure provided within a body of adsorbent. The closure may
comprise a spiralled or curved tube. The closure may contain at
least one of i) water; or ii) phase change material.
[0131] The adsorbent may be provided as a body of adsorbent
material and the body may be provided with surface area maximising
means which may comprise any one of the of following: i) channels
provided on or within the body; ii) the adsorbent being provided in
granular form or in powder form.
[0132] A membrane may be provided to separate the adsorbent and
refrigerant prior to the actuator allowing the refrigerant to be
adsorbed.
[0133] The wick may be provided with apertures, which may assist in
the prevention of ice. The adsorbent may be provided as a body and
there are distributed in the adsorbent body of a plurality of
microcapsules comprising water or a waxy phase change material. The
microcapsules may contain phase change material which melts, in
use, and wherein the microcapsules have a sheath to retain the
melted phase change material. The adsorbent may be provided as a
body, and wherein the adsorbent body has provided in it a plurality
of channels adapted to take refrigerant vapour to different regions
of said body.
[0134] The self cooling beverage container may have a beverage
chamber, a beverage in the beverage chamber, a body of adsorbent
material, an evaporative refrigerant held on wick, an isolator
isolating the wick from the adsorbent body, an actuator adapted in
use to communicate the adsorbent with the wick so that said
evaporative refrigerant evaporates and is adsorbed by the
adsorbent, with the evaporation cooling the beverage; and wherein
the adsorbent is activated carbon, the evaporature refrigerant is
water, and the evaporative process occurs at sub atmospheric
pressure; and wherein a mixer is provided in said beverage chamber,
said mixer being gravity operated by inversion of the container to
cause said mixer to move and thereby mix the beverage to assist
cooling of the beverage; and wherein said adsorbent body has heat
take up means provided in it, said heat take up means comprising at
least one of; i) microcapsules of phase change material or heat
capacity material distributed in said body; ii) liquid cooled
surfaces provided on said adsorbent body; and wherein said wick is
thermally coupled with at least one of: i) heat exchange fins
extending into said beverage; ii) extensions or loops of wire in
thermal contact with said beverage.
[0135] A method of cooling a beverage may comprise providing a
container having a gravity powered beverage mixer and actuating
said actuator, and then periodically inverting said container to
cause said gravity moved member to move repeatedly through said
beverage, in opposite directions relative to said conductor, and
repeatedly moving said beverage prior to opening said beverage
container.
[0136] Embodiments of the invention will now be described by way of
example only, with reference to the accompanying drawings in
which:
[0137] FIG. 1 shows a self-cooling can of beverage in accordance
with the invention;
[0138] FIG. 2 shows a modification of the device shown in FIG.
1;
[0139] FIG. 3 is a further embodiment of the heat transfer device
showing the use of heat exchange means to enhance a transfer;
[0140] FIGS. 4A to C show the sequence of events for using the
embodiment shown in FIG. 3;
[0141] FIG. 5 is a modification of the device shown in FIG. 3;
[0142] FIG. 6 is a further embodiment of the heat transfer device,
in which the adsorbent is arranged around the material, and a
conduit arrangement is used to deliver evaporated refrigerant to
the adsorbent;
[0143] FIG. 7 is a further embodiment of the heat transfer
device;
[0144] FIG. 8 is a further embodiment of the heat transfer device
using an enlarged chamber for the adsorbent;
[0145] FIG. 9 shows schematic representations of further possible
enhancements of the system;
[0146] FIGS. 10A to 10D show heat take up mechanisms which may be
provided associated with the evaporant take up medium;
[0147] FIGS. 11A to 11B show heat sink material distributed in
adsorbent/evaporant take up material;
[0148] FIGS. 12A to 12C show further heat sink structures;
[0149] FIGS. 13A to 13D show ways of getting the evaporated coolant
to deeper parts of a body of evaporant take up material;
[0150] FIG. 14 shows a way of cooling the adsorbent/take up
agent;
[0151] FIG. 15 shows a self-cooling beverage container with a
temperature gradient over the volume of adsorbent;
[0152] FIG. 16 shows an embodiment of the heat take up means;
[0153] FIG. 17 shows a further embodiment of the heat take up
means;
[0154] FIG. 18 shows an elongate capsule containing phase change
material; and
[0155] FIG. 19 shows wicking means provided with apertures.
[0156] Referring to FIG. 1 there is shown a can 300 having a heat
transfer device 410 comprising a first part 416 having a
cylindrical chamber 419 for an adsorbent 418 (e.g. activated
charcoal), and a second part 420 which cools a beverage 422 (e.g.
beer, lager, soft drinks or the like) to be cooled, and comprises a
double skin in the form of a pair of concentrically arranged outer
and inner walls 424, 426. Wicking means 428 is provided on and
surrounds the inner wall 426. The wicking means 428 is soaked in a
suitable refrigerant, for example water, and can be a porous fabric
material capable of dispersing the refrigerant throughout the
fabric by capillary action. One example of a suitable fabric is
that sold under the Trade Mark J-Cloth. The space between the outer
and inner walls 424, 426 is evacuated to a low pressure. Mixing
means in the form of a disc or body 430 provided with a plurality
of perforations is provided in the beverage 422, the purpose of
which is explained below.
[0157] Operative means in the form of a plunger 432 is provided in
the first part 416 and comprises an elongate rod 434 extending
between a button 436 to be pressed to operate the operative means
432, and piercing means 438 at the opposite end region of the rod
434 to pierce a membrane 440 separating and isolating the first and
second parts from each other. The operative means extends through
an elongate hole 435 through the cylindrical chamber 417.
[0158] The piercing means 438 is in the form of a substantially
cylindrical member, the lower end 439 being open. The edge of the
cylinder surrounding the open end is sharp and can readily pierce
the membrane 440 which is in the form of a suitable plastics or
metal foil, for example aluminium foil.
[0159] In operation, the button 436 is depressed which causes the
piercing means 438 to pierce the membrane 440. Upon piercing of the
membrane, the water in the space between the outer and inner walls
424, 426 is adsorbed by the adsorbent 418, and evaporates from the
wicking means 428 thereby extracting heat from the beverage 422. In
order to ensure that heat is extracted from all parts of the
beverage 422, the device 410 is inverted to enable the mixing disc
430 to descend under gravity thereby creating eddy currents in the
beverage 422 and stirring the beverage.
[0160] As the water evaporates from the wicking means, it is
absorbed by the adsorbent 418 until all the water has been so
adsorbed or until the adsorbent is substantially exhausted and
there is no further significant driver to the evaporative
process.
[0161] A ring pull 442 is provided to open an aperture in the can
and allow the beverage to be consumed.
[0162] Referring to FIG. 2, there is shown a modification of the
device shown in FIG. 36 in which the first part 416 is surrounded
by heat absorption means, or a heat sink 444. The heat sink 444
absorbs heat from the adsorbent 418.
[0163] The heat sink 444 could, for example, be further wicking
means, soaked in a suitable refrigerant e.g. water, whereby as the
adsorbent releases heat of adsorption, the refrigerant evaporates
thereby removing the heat of adsorption from the device. Again, the
further wicking means could be a porous cloth, for example a cloth
sold under the Trade mark J-Cloth.
[0164] Alternatively, in an embodiment not shown, the further
wicking means could be provided around the inside walls of the
elongate hole 435.
[0165] Micro capsules containing water may be provided in the
further wicking means to enhance the removal of heat of adsorption.
The micro capsules may contain water (or other high heat capacity
material) or they may contain phase change material. It is
envisaged that of the order of tens, several tens, hundreds,
several hundred, or even thousands of microcapsules would be used.
The microcapsules may not have an outer skin and a core of
different material; they could be of a single material (e.g. wax
pellets) or metal powder or granules.
[0166] Both the first part and the second part of both embodiments,
shown in FIGS. 1 and 2 are placed under vacuum.
[0167] The adsorbent is placed in a cylinder made from stainless
steel or copper mesh. The operative means extends through the hole
435 through the centre of the cylinder.
[0168] Referring to FIGS. 3 to 5, there is shown a heat transfer
device 510 which comprises a first part 512 which holds an
adsorbent 514 (e.g. activated carbon) arranged in a cylinder of
stainless steels or copper mesh 516. A second part 518 is provided
on the first part 512 and extends into a beverage to be cooled 520.
The second part 518 consists of a cylindrical tube 522 having
provided on the inner surface thereof wicking means 524 which is
saturated with a suitable refrigerant, for example, water. Heat
exchange means in the form of wire filaments, loops, protrusions,
or fins 526 extend outwardly from the tube 522. Both the first and
second parts 512, 518 are under vacuum/low pressure.
[0169] Operative means 528 is provided in the first part 512 and
extends through a bore in the cylinder holding the adsorbent 514.
The operative means 528 comprises a button 530 and piercer 532
adapted to pierce a membrane 534 separating and isolating the first
and second parts from each other. A rigid rod 536 extends between
the button 530 and the piercing means 532 such that depression of
the button 530 causes the piercing means 532 to pierce the membrane
534.
[0170] Referring to FIGS. 4A to 4C, there is shown the sequence of
events for using the device shown in FIG. 3.
[0171] FIG. 4A shows the device as it appears in FIG. 3 i.e. before
operation. Referring to 4B, when it is desired to consume the
beverage 520, the button 530 is pushed down. This causes the
piercing means 532 to be pushed through the membrane 534 by the rod
536 and ruptures the membrane 534.
[0172] Immediately this is done, the water on the, pre-wet, wicking
means 524 evaporates and is adsorbed by the absorbent 516. This
extracts heat from the beverage 520 and this heat extraction is
enhanced by the fins 526. The fins 526 could be bushes of wire
strands, for example like wire wool. This would have a large
surface area and good thermal conductivity, and would allow the
beverage 520 to flow through the bushes.
[0173] When the heat transfer has been completed, and the beverage
520 is cooled, a ring pull 538 can be pulled to allow the beverage
520 to be poured into a glass 540 for consumption.
[0174] Referring to FIG. 39, there is shown a modification to the
device shown in FIG. 37 in which the inside of the tube 522 forming
the second part 518 is provided with an internal arrangement 542 of
looped wire, similar to that provided outside.
[0175] A filter may be provided to prevent any parts of the heat
exchange mechanism that have broken off in transport, storage, or
use, of the container from being dispensed from the can via the
aperture by the ring pull. The heat exchanger or cooling unit may
be provided in a porous/permeable bag/shroud.
[0176] Referring to FIG. 6, there is shown a further embodiment 610
in which a first part 612 comprises a vessel having a double skin
inner and outer wall 616, 618, the adsorbent 614 being arranged
circumferentially around the outer wall 618. An inner tube 620
extends into the beverage 622 and comprises wicking means 624
arranged internally of the tube 620, and fins 626 extending
outwardly from the tubes 620 into the beverage 622. The second part
628 is provided separate from the vessel, and comprises a copper
container 630 holding a refrigerant 632, for example water. A
conduit 636 extends from the container 628 to a region adjacent the
bottom of the tube 620. A valve 638 is provided in the pipe 636
which is initially set to its closed position and, upon opening,
allows water in the container 630 to flow into the tube 620. An
arrangement of conduits 640 extends from the tube 620 into the
first part 612 for the purpose of delivering evaporated refrigerant
to the first part 612. A water trap 642 is provided at the top of
the tube 620 to connect the tube 620 to the conduit arrangement
640, whereby any water condensing prior to entering the conduit
arrangement 640 is returned back to the tube 620 to undergo
evaporation again.
[0177] In operation, the valve 638 is opened and water from the
container 630 is emptied into the tube 620. The water is then
dispersed by the wicking means around the inside of the tube 620
and is evaporated by the transfer of heat from the beverage via the
fins 626. The evaporated water thereby extracts heat from the
beverage to cool it down. Water vapour passes through the tube via
the conduit arrangement 640 into the first part 612 to be adsorbed
by the adsorbent 614 arranged on the outer wall 618. A covering of
insulating material 644 is provided around the inner wall 616 to
ensure that, once cooled, the beverage 622 is kept cool. When the
cooling process is completed, the ring pull 646 can be pulled to
allow the beverage to be consumed. The ring pull 646 could be a
closable closure, to enable the beverage chamber to be sealed
closed after opening, and possibly re-filled with beverage.
[0178] A lid 648 is provided which can be removed to allow the
water in the adsorbent 614 to be discharged thereby allowing the
device to be used again.
[0179] Referring to FIG. 7, there is shown a modified device 710
which comprises an inner cylinder 712 holding a beverage 714.
Wicking means 716 is provided on the wall of the cylinder 712. An
outer wall 718 is provided on the inside thereof with an adsorbent
720 which extends substantially wholly around the inside of the
wall 718.
[0180] A container 722 is provided separate from the vessel and
contains a suitable refrigerant, for example water. The container
722 is connected to the wicking means 716 via a conduit 724 and a
valve 726. The space between the inner and outer walls 712, 718 is
under vacuum.
[0181] On operation, the valve 726 is opened to allow the water in
the container 722 to empty into the space between the two walls
718, 712 whereupon the water is dispersed around the outside of the
cylinder holding the beverage 714. In evaporation the water
therefrom extracts heat from the beverage 714. The evaporated
refrigerant is then adsorbed by the adsorbent 720 surrounding the
inside of the outer wall 718. In this way, the beverage 714 is
cooled
[0182] A lid 728 (e.g. plastic) is provided to cover the space
between the inner and outer wall 718, 712 and the conduits 724 is
formed in the lid 728. An evacuation point 730 is provided on the
lid, to allow the water adsorbed onto the adsorbent 720 to be
discharged therefrom to allow the device to be used again. The
container 722 can be refilled with water through a suitable fill
point 732. The container 722 is suitably formed from copper.
[0183] Referring to FIG. 8, there is shown a further embodiment 710
and is formed in two separate but connected elements 712. The first
element 712 comprises a large cylinder the adsorbent 718 extends
substantially wholly around the inside of the wall of the cylinder
716. A lid 720 is provided on the cylinder to allow water adsorbed
onto the adsorbent 718 to be reused.
[0184] The second element 714 comprises a tubular member 722 having
provided on the outside thereof a plurality of fins 724. Wicking
means 726 extends around the inside of the wall of the tube 722. A
container 728, initially charged with a refrigerant, for example
water is provided separately from. the tube 722 and is connected
thereto by pipes 730 and a valve 732. A flange 734 is provided to
connect the two elements 712, 714 together.
[0185] On operation, the first element 712 is connected to the
second element 714 by the flange 734 The tube 722 is then inserted
in a material to be cooled, and a valve 732 is opened to allow the
water to enter the tube 722 to be dispersed around the inside wall
of the tube. Heat is transferred to the inside of the tube via the
fins 724 to evaporate the water thereby cooling the material. The
evaporated water is then passed into the first element 712 to be
adsorbed by the adsorbent 718. When the process is completed, the
cooled material can be consumed, and the first clement can be used
again by removing the water from the adsorbent 718 by, for example,
heating.
[0186] FIG. 9 is based upon FIG. 3 but shows enhancements which may
be provided. The skilled person will appreciate that the
enhancements shown in relation to FIG. 9 could equally well be
applied to any other of the embodiments shown in the various
Figures of this description.
[0187] FIG. 9a shows pockets 800 of a phase change material
provided within the within the take up agent (e.g. adsorbent) 514.
As the device is used the temperature of the take up agent 514
rises and eventually the material provided within the pockets
either melts, vaporises, or sublimates. This change of phase of the
material within the pocket 800 requires a heat input which is
absorbed from the take up agent 514. This absorption of heat
reduces the temperature of the take up agent thus improving the
rate of cooling of the beverage 520. The absorbing/take up reaction
of the take up agent/evaporant is an equilibrium reaction and
operates faster the further away from equilibrium--it is therefore
helpful to cool the take up agent to maintain the speed of reaction
and hence speed of cooling of the beverage.
[0188] FIG. 9b shows a tube 802, provided as a spiral within the
take up agent 514. The tube is fabricated from a metal, in this
case aluminium, so that it conducts heat rapidly. The tube is
filled with water which absorbs heat from the take up agent 514
again increasing the rate of cooling of the beverage 520. The tube
and its water is a heat sink.
[0189] FIG. 9c shows cooling fins 804 extending into the take up
agent 514. As with the embodiments shown in FIGS. 9a and 9b the
fins are adapted to remove heat from the take up agent 514 so that
its rate of change of temperature is reduced which promotes cooling
of the beverage 520. The fins 804 are substantially flat and
parallel plates.
[0190] FIG. 9d shows the provision of insulation around the heat
transfer device 510. A portion of insulation 806 is provided
between the first part 512 (containing the take up agent) and the
beverage container 808 which is adapted to prevent heat from the
take up agent 517 from reaching the beverage 520. It will be
appreciated that in this embodiment the heat transfer device is
adapted to cool the beverage 520 and that therefore it is not
desirable for heat to reach the beverage 520.
[0191] A portion of insulation 810 is provided around the beverage
container 808 and is adapted to prevent heat reaching the beverage
520 from the atmosphere.
[0192] A further portion of insulation 812 is provided around the
first part 512 and is adapted to prevent the outside of the heat
transfer device 510 from becoming too hot. It will be appreciated
that the take up agent is absorbing heat and will therefore
experience a temperature rise. This may become dangerous or
uncomfortable for a user. Indeed, this may cause a psychological
effect wherein the user knows that the heat transfer device 510 is
adapted to cool the beverage 520 but is somewhat surprised by the
device 510 becoming hot and may not perceive the cooled beverage as
really being as cold as it is.
[0193] FIG. 9e shows channels 814 provided within the take up agent
517. These channels are adapted to maximise the surface area of the
take up agent and improve efficiency of the cooling process of the
beverage 520. They take the water vapour (evaporant) to different
regions of the take up agent, preventing localised saturation of
the take up agent (and localised heating) which would serve to
stop/retard the equilibrium drive of the process: ensuring that
substantially the whole body of the take up agent is exposed to
water vapour makes for a further cooling process for the
beverage.
[0194] The skilled person will appreciate that the features shown
in FIG. 9 are applicable to any of the embodiments shown herein,
including those adapted to heat a beverage or food stuff. Indeed,
some embodiments may have a combination of the features shown in
FIG. 9. With respect to FIG. 9d only some of the portions of
insulation may be provided, and the purpose of the insulation may
be different (although readily apparent) if it is provided on
devices adapted to heat a beverage or foodstuff.
[0195] Where "heat-pipe" is referred to in the foregoing
description, it is to be understood as including any one or more of
needle heat-pipes, loop heat-pipes or micro heat-pipes.
[0196] Various modifications can be made without departing from the
scope of the invention. For example, each of the embodiments shown
above comprises one adsorber or absorber unit. The devices may
comprise two or more absorber or adsorber units to enhance the
cooling/heating programme. Also, a device may comprise a
combination of solid/gas adsorption and liquid/gas absorption. In
the pocket/portable coolers/heaters (or, indeed any of the
embodiments shown in the drawings) the refrigerant may be desorbed
from the adsorbent to allow the adsorbent to be re-used.
[0197] FIGS. 10a to 10d show heat sink devices which in some
embodiments may be provided distributed in the evaporant take up
agent/adsorbent. A spiral shape, such as that of FIG. 10a, or a
convoluted shape, as in FIG. 10d (which need not be planar) are
space-efficient. Smaller, simpler shapes such as shown in FIGS. 10b
and 10c may be used. The heat sink devices may simply be of a
material with high heat capacity (e.g. metal), or they may be of a
phase change material, e.g. wax. They may have an outer skin or
sheath of one material and a core of another (e.g. metal, or cloth,
or plastics skin with a phase change core). They may be distributed
through the body if adsorbent.
[0198] FIG. 11a shows a cake of adsorbent (e.g. carbon) 900 having
heat sink, particles 902 randomly distributed in it. The heat sink
particles 902 are made of metal in this example. FIG. 11b shows a
cake of adsorbent (e.g. carbon or zeolite) with both metal
particles 902, and phase-change heat sink particles 904 distributed
within it. The phase change particles are preferably non-toxic to
humans, as are preferably all materials in the container/can. That
is why carbon/water is preferred as the adsorbent/evaporant, and
why wax is preferred as heat sink/phase change material.
[0199] FIG. 12a shows a heat sink/sphere 910 having a stem 912
containing a core 914. The core 914 is of high heat capacity
material, e.g. water. The stem 912 is a good thermal conductor,
e.g. a metal foil/metalised membrane. FIG. 12b shows a capsule 916
having an outer wall 918 of retaining material, e.g. wax, cloth,
metal or plastic, and a core 920 of phase change material.
[0200] FIG. 12c shows a capsule 920 having an outer skin 922, an
inner core 924, and an intermediate layer 926. The intermediate
layer 926 could be of a phase change material or high heat capacity
material and could be solid or liquid. The core could be of phase
change material or high heat capacity material and would be solid
or liquid. In one version the core is water and the intermediate
layer is a phase change material, such as wax. The outer stem may
itself be of wax and may or may not melt in use (e.g. the wax of
the skin could have a higher melting point that that of the
intermediate layer or core).
[0201] FIG. 13a shows a body 930 of adsorbent (or other evaporant
take up agent) having a number of channels 932a, 932b, 932c, 932d,
provided in it. Each channel 932 has its own entrance 934 and water
vapour (or other evaporant vapour) enters via the entrances 934.
This ensures (and the aim of the improvement is to ensure) that not
all of the water vapour is adsorbed at the end, referral 936, of
the body of adsorbent near the vapour entrance to the body. If no
channels/guide/splitter for the vapour was not provided the vapour
may tend to condense on the lower parts of the body first, and the
adsorption reaction would be greatly unequal over the height of the
body 930. The separate channels 932a to 932d ensure that "fresh"
vapour reaches the further/remote parts of the adsorbent.
[0202] The right hand half of FIG. 13a shows another modification
in which the passages/channels 932 are not simply straight, but are
convoluted (938) in order to have a larger surface area/have less
of the body of adsorbent so far away from the nearest channel
portion/place where water can be adsorbed. Of course, the channels
can have an arcuate extent around the can/container, and may have
both a circumferential extent and an axial extent. The body 930 may
be made of sections which define the channels between them, as
shown in FIG. 13d. The sections may be circular and may stack one
above the other, possibly with protrusions to hold them apart so as
to define the channels.
[0203] FIG. 13b shows another body of adsorbent/take up material
940 which has a channel 942 into which vapour enters at entry 944.
The channel 942 is shaped so that at its entry the vapour is
flowing relatively quickly, and such that further downstream in the
channel, for example at point 946, the flow is slower. This means
that vapour reaches the downstream regions of the channel since at
least some of it rushes past the upstream surfaces of adsorbent
before it can be adsorbed, thereby spreading out the adsorption
over a larger volume of the body, or makes the adsorption more even
over the volume of the body. This may be achieved in part by having
the channel 942 have an increased cross-sectional area at a region
downstream of the entry 944, and it may have a progressively, or
stepped, widening of cross-section.
[0204] FIG. 13c shows another way of spreading out the adsorption
of reaction over a larger volume of body of adsorbent.
[0205] FIG. 14 shows a body 950 of adsorbent (or other take up
material) 951 with a liquid cooling system. Water cooling channels
952 are provided and movable circulation drivers 954 are provided
in the channels 952, as is water 955. Access to the adsorbent 951
for the evaporated water vapour (or other vapour) is not shown, but
does exist. In this example the circulation drivers 954 are bodies
with a through bores 956. When the body 950 is inverted the drivers
954 slide down the channels 952, with the water 955 flowing through
the bores 956 as they move under gravity. This causes turbulent
mixing of the water 955, which aids heat transfer from the body 950
to the water 955. The drivers 954 may be parts of a common member,
e.g. a plate. They may not be of the same cross-section as the
channels, allowing water to slide past them. They may not then need
bores 956.
[0206] The coolant liquid circulation achieved by drivers 954 is,
of course, similar to that achieved by plate 430 for the beverage
itself. The plate 430 and driver 954 may be different components,
or they may be provided by a common gravity driven component. In a
modification instead of being gravity driven the beverage mixer
and/or coolant fluid mixer may be manually driven. They may be
gravity driven as they fall, and manually returnable to an elevated
position. Alternatively the user may be directed to turn the
container upside down periodically whilst it cools, so as to enable
the plate 430 and/or drivers 954 to operate repeatedly.
[0207] FIG. 15 shows a temperature gradient over a block of
adsorbent. This may encourage the reaction to use the cooler parts
of the block. The usage of the block may therefore be in part
self-regulating. However, for maximum speed of cooling of the
beverage large temperature gradients over the adsorbent are to be
avoided since they demonstrate that some parts of the adsorbent are
not taking up as much vapour as they could be (and indeed as other
parts of the adsorbent are taking up).
[0208] The performance of the self-cooling can/container is
intended to cool a can at an initial temperature of 20-25.degree.
C. to a final temperature of around 8.degree. C..+-.a few .degree.
C. in a time of 2 minutes or less.
[0209] It will be appreciated that the self-cooling container of
main interest is likely to be a can, or other container having
about 300-500 ml or so of beverage. Typical cans and bottles have
275 ml, 330 ml, 440 ml, 500 ml of beverage, and the temperature
reduction performance envisaged is for such containers.
[0210] Details of particular variants of the heat take up means are
shown in FIGS. 16 to 18.
[0211] FIG. 16 shows a possible embodiment of the heat take up
means. A plurality of wire loops 961 are connected to a common core
962.
[0212] FIG. 17 shows a further possible embodiment of the heat take
up material. A plurality of wires 971 each have a first end
connected to a common core 962.
[0213] Either of the assemblies shown in FIGS. 16 or 17 have the
advantage that they can be assembled into one piece and then,
depending on the make up of the adsorbents have the adsorbent
poured over them to fill the space around the assembly, being a
simple method of manufacture.
[0214] FIG. 18 shows a cross section of an elongate capsule 982 of
heat take up material. It consists of an outer layer 918 of wax
surrounding an inner core 920, such that the melting point of the
inner core 920 is lower than that of the outer layer 918 so that in
use the outer layer 918 retains the inner core 920 if the inner
core 920 melts. These may then be distributed throughout the
adsorbent.
[0215] FIG. 19 shows wicking means 428, provided with a plurality
of apertures 991 arranged about the inner wall 426 of FIG. 1. In
use, as the beverage 422 cools ice will preferentially form about
the apertures 991 rather than the surface 992 of the wicking means
428, meaning that the refrigerant is free to evaporate from said
surface 992.
[0216] Whilst endeavouring in the foregoing specification to draw
attention to those features of the invention believed to be of
particular importance it should be understood that the Applicant
claims protection in respect of any patentable feature or
combination of features hereinbefore referred to and/or shown in
the drawings whether or not particular emphasis has been placed
thereon.
* * * * *