Note: Descriptions are shown in the official language in which they were submitted.
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DISPENSER ASSEMBLIES AND SYSTEMS
INCLUDING A HEAT STORAGE UNIT
FIELD OF THE INVENTION
[0002] Our invention relates to a heat storage unit for a flowable product and
to dispenser
assemblies and systems utilizing such a heat storage unit. The heat storage
unit is heatable by
either induction heating or microwave heating. Our invention also relates to a
method of
manufacturing a heat storage unit.
BACKGROUND OF THE INVENTION
[0003] Dispenser assemblies for dispensing a heated product are known in the
art.
Conventional dispenser assemblies typically include a container for holding a
flowable
product, a mechanism to expel the product from the container, and, in some
instances, an
electrical heating element for heating the product prior to being dispensed.
For example,
each of U.S. Patent No. 3,144,174 to Abplanalp and U.S. Patent No. 3,644,707
to Costello
discloses an aerosol dispenser assembly having a heating element for heating a
flowable
product, such as shaving cream, prior to dispensing. In each of these patents,
the heating
element is disclosed as being an electrical resistance heating element.
However, the
Abplanalp patent also suggests that the dispenser assembly may use heating
elements having
"other conventional forms," including an "induction type" heating element.
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[0004] The Costello patent further discloses that a heat storage medium, such
as water,
alcohol, powdered metal, or the like, may be used to absorb and retain heat
generated by an
electric resistance heating coil. According to the Costello patent, the heat-
retaining medium
stores heat for only a few minutes so that after the dispenser assembly is
unplugged from a
wall socket, warm shaving cream is still available for a single shave.
SUMMARY OF THE INVENTION
[0005] Our invention provides an improved heat storage unit and a method of
manufacturing
the same, a dispenser assembly, and a system for heating a flowable product,
which is easy to
use, fast, safe, and is capable of heating a flowable product during extended
periods of use.
[0006] In one aspect, our invention relates to a heat storage unit that heats
a flowable product
prior to dispensing. The heat storage unit comprises a body having a passage
formed therein
through which a flowable product passes, and a heatable element incorporated
within the
body in thermal communication with the passage. The heatable element comprises
either a
magnetically-compatible material or a microwave-compatible material that is
heatable by
locating the heatable element in a field generated external to the heat
storage unit. The heat
storage unit does not include any components for generating a field to heat
the heatable
element, and, preferably, is cordless.
[0007] Preferably, the heatable element comprises a magnetically-compatible
material that is
heatable by locating the heatable element in a magnetic field. The heatable
element may
comprise a ferromagnetic material, such as stainless steel or a temperature
sensitive alloy, or
a graphite-based material, such as a flexible graphite-based sheeting material
or a rigid
graphite-filled polymer. The heat storage unit may also include an
identification device (e.g.,
a radio frequency identification device) that stores information about the
heat storage unit or
about a flowable product used therewith. The heat storage unit can be
configured as a
cartridge that is detachably securable to a variety of different flowable
product dispensers, as
an overcap for an aerosol container, or as a porous pad.
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[0008] Alternatively, instead of a magnetically-compatible material, the
heatable element
may comprise a microwave-compatible material that is heatable by exposing the
heat storage
unit to microwave radiation.
[0009] In another aspect, our invention relates to a system that includes a
heat storage unit
and a charging device. The heat storage unit comprises a body having a passage
formed
therein and a heatable element incorporated within the body in thermal
communication with
the passage. The heatable element comprises either a magnetically-compatible
material or a
microwave-compatible material. The heat storage unit is detachably docked with
the
charging device, such that when the charging device is activated, a field is
generated that
encompasses the heatable element of the heat storage unit, thereby raising the
temperature of
the heatable element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. IA is a simplified cross-sectional view of a system according to a
first
embodiment of our invention taken along line IA--lA shown in FIG. 1E,
including a heat
storage unit and a wall-mounted charging device. Hatching of the heat storage
unit has been
omitted for clarity throughout the drawing figures.
[0011] FIGS. 1B-1D are simplified cross-sectional views showing alternative
configurations
of the heat storage unit of the first embodiment of our invention, taken along
line lB--1B
shown in FIG. 1E.
[0012] FIG. 1E is a perspective view showing the relationship of the heat
storage unit to the
charging device in the system of FIG. 1A.
[0013] FIGS. IF and 1G are perspective views showing various dispenser
assemblies
employing a heat storage unit according to the first embodiment.
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[0014] FIG. 2A is a cross-sectional view of a hot-shave dispenser assembly
employing a heat
storage unit according to a second embodiment, attached to a wall-mounted
charging device.
[0015] FIG. 2B is a perspective view of the hot-shave dispenser assembly of
FIG. 2A,
attached to a wall-mounted charging device.
[0016] FIG. 2C is a perspective view showing how, in one example, the
dispenser assembly
of FIG. 2A attaches to the charging device.
[0017] FIG. 3A is a cross-sectional view of a hot-shave dispenser assembly
employing a heat
storage unit according to a third embodiment, attached to a wall-mounted
charging device.
[0018] FIG. 3B is a perspective view of the hot-shave dispenser assembly of
FIG. 3A,
attached to a wall-mounted charging device.
[0019] FIG. 4A is a perspective view of a hot-shave dispenser assembly
employing a heat
storage unit according to a fourth embodiment.
[0020] FIG. 4B is a perspective view of a system including the hot-shave
dispenser assembly
and heat storage unit of FIG. 4A and a wall-mounted charging device.
[0021] FIG. 4C is a cross-sectional view of the system of FIG. 4B, taken along
line 4C--4C
shown in FIG. 4B.
[0022] FIG. 4D is a cross-sectional view of an alternative configuration to
that shown in FIG.
4C.
[0023] FIG. 4E is a cross-sectional view of another alternative configuration
to that shown in
FIG. 4C.
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[0024] FIG. 4F is a cross-sectional view of yet another alternative
configuration to that
shown in FIG. 4C.
[0025] FIG. 5A is a cross-sectional view of a hot storage unit configured as a
porous pad, in
accordance with a fifth embodiment of our invention.
[0026] FIG. 5B is a perspective view of a system including the porous pad of
FIG. 5A and a
charging device.
[0027] FIG. 5C is a cross-sectional view of the system of FIG. 5B, taken along
line 5C--5C
shown in FIG. 5B.
[0028] FIG. 6 is a schematic representation of the electronic components of
the charging
device of the various embodiments.
[0029] FIG. 7 is a flow chart illustrating a method of manufacturing the heat
storage unit of
FIG. 1 A.
[0030] FIG. 8 is a flow chart illustrating a method of manufacturing the heat
storage unit of
FIG. 113.
[0031] FIG. 9 is a flow chart illustrating an alternative method of
manufacturing the heat
storage unit of FIG. 1B.
[0032] Throughout the drawing figures, like or corresponding reference
numerals denote like
or corresponding elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Our invention relates generally to a heat storage unit, a dispenser
assembly, and a
system for heating a flowable product, such as a cleaning solution, an air
freshener, a shaving
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gel or cream, a lotion, an insecticide, or the like. More specifically, the
system of our
invention includes a heat storage unit 2 that is capable of being used either
as part of a
dispenser assembly or alone, and a charging device 6 for charging, or
energizing, the heat
storage unit. The terms "charging" and "energizing" are used interchangeably
herein to mean
to impart energy to the heat storage unit by, among other ways, exposing the
heat storage unit
to a magnetic field or to microwave radiation. The heat storage unit 2 serves
to impart heat to
a flowable product prior to the flowable product being dispensed.
[0034] The heat storage unit 2 preferably comprises a heat-retentive material
8 and a heatable
element 10 arranged in thermal communication with each other. Alternatively,
the heat-
retentive material 8 is not necessary and can be omitted, if desired. A
passage 12 is formed in
the body of the heat storage unit 2 and defines a flow path through which the
flowable
product passes during dispensing. The heat storage unit 2 also may optionally
include an
insulating shell layer 24 that covers at least a portion of the surface of the
heat storage unit 2.
When the heat storage unit 2 is docked with the charging device 6 and the
charging device is
activated, the heat storage unit 2 develops and stores heat, thereby becoming
charged. The
heat storage unit 2, thus charged, gradually meters out heat to the flowable
product in the
passage 12, so as to provide heat over an extended period of time.
[0035] The heatable element 10 preferably comprises a magnetically-compatible
material
("MCM"). As used herein, the term "magnetically-compatible material" means a
material
that is capable of being heated by exposure to an alternating magnetic field,
specific
examples of which are discussed in more detail below. Preferably, the heatable
element 10
comprises a ferromagnetic metal or alloy, such as, for example, stainless
steel or a
temperature sensitive alloy ("TSA"). TSAs lose their magnetic properties when
heated above
a specific temperature, thereby providing a built-in safety mechanism to
prevent overheating.
U.S. Patent No. 6,232,585 discloses examples of ferromagnetic materials
suitable for use
as the heatable element 10.
[0036] Alternatively, the heatable element 10 could comprise a graphite-based
material, such
as GRAFOIL or EGRAFTM sheeting, which are flexible graphite sheeting
materials
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available from Graftech Inc. of Lakewood, Ohio (a division of UCAR Carbon
Technology
Corporation). Another preferred graphite-based material is a rigid graphite-
filled polymer
material available under the designation BMC 940 from Bulk Molding Compounds,
Inc. of
West Chicago, Illinois. Still other rigid, graphite-based materials having
smaller amounts of
polymer filler than the BMC 940 may also be used. These graphite-based
materials are
discussed in U.S. Patent Nos. 6,657,170 and 6,664,520,
[0037] GRAFOIL and EGRAFTM sheeting are graphite sheet products made by
taking high
quality particulate graphite flake and processing it through an
intercalculation process using
strong mineral acids. The flake is then heated to volatilize the acids and
expands to many
times its original size. No binders are introduced into the manufacturing
process. The result
is a sheet material that typically exceeds 98% carbon by weight. The materials
are flexible,
lightweight, compressible, resilient, chemically inert, fire safe, and stable
under load and
temperature.
[0038] GRAFOIL or EGRAFTM sheeting are significantly more electrically and
thermally
conductive in the plane of the sheet than in a direction through the plane. It
has been found
experimentally that this anisotropy has two benefits. First, the higher
electrical resistance in
the through-plane direction allows the material to have an impedance at 20-50
kHz that
allows a magnetic induction heater operating at such frequencies to
efficiently heat the
material while the superior thermal conductivity in the plane of the sheet
enables the sheet to
be quickly and uniformly heated across its entire width. Second, successive
layers of
GRAFOIL or EGRAFTM sheeting can be inductively heated simultaneously, even if
each
layer is electrically insulated from the next. For example, each layer of
GRAFOIL sheeting
in a laminated structure comprising several layers of GRAFOIL sheeting
sandwiched
between layers of an insulative or heat-retentive material can be inductively
heated at
approximately equal heating rates.
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[0039] The BMC 940 rigid graphite-filled polymer material also has advantages
for use as
the heatable element 10 of our invention. Its ability to be injection or
compression molded
into complex shapes allows it to be easily formed into any desired shape or
size.
[0040] Alternatively, instead of MCMs, the heatable element 10 could comprise
a
microwave-compatible material ("MiCM"). The term "microwave-compatible
material" is
used herein to refer to any dielectric insulator that absorbs energy when
exposed to
microwave radiation (i.e., electromagnetic radiation having a frequency in the
range of about
300 Megahertz to about 300 Gigahertz), thereby causing a heating effect within
the MiCM.
[0041] If used, the heat-retentive material 8 preferably comprises a solid-to-
solid phase
change material. Solid-to-solid phase change materials reversibly store large
amounts of
latent heat per unit mass through solid-to-solid, crystalline phase
transformations at unique
constant transformation temperatures that are well below their respective
melting points. The
transformation temperature can be adjusted over a wide range of temperatures,
from about
C to about 188 C, by combining different solid-to-solid phase change
materials. U.S.
Patent Nos. 6,316,753 and 5,954,984 each contains a discussion of solid-to-
solid phase
change materials suitable for use in our invention.
[0042] The solid-to-solid phase change material preferably contains at least a
polyethylene
resin, and may also include structural additives, thermal conductivity
additives, antioxidants,
and the like. Preferably, at least about 70% by weight of the heat-retentive
material is a
polyethylene resin, such as a low density polyethylene resin or a linear low
density
polyethylene resin. Examples of preferred resins for use in our invention
include: a linear
low density polyethylene resin designated as GA 564 from Equistar Chemicals,
LP of
Houston, Texas; a metallocine linear low density resin designated as mPact
D139 from
Phillips Petroleum Company of Houston, Texas; and a low density polyethylene
resin
designated as LDPE 6401 from Dow Plastics of Midland, Michigan. Other
polyethylene
resins of varying densities can also be used in our invention.
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[0043] One or more antioxidants may be added to the polyethylene resin, by
compounding or
the like, in order to deter deterioration of the heat-retentive material
during its life of periodic
exposure to temperatures above its crystalline melting temperature. Examples
of preferred
antioxidants include: IRGANOX 1010 or IRGANOX 1330 produced by Ciba
Specialty
Chemicals of Switzerland; UVASIL 2000 LM produced by Great Lakes Chemical
Corporation of West Lafayette, Indiana; ULTRANOX 641 and WESTONTM 618
produced
by GE Specialty Chemicals of Parkersburg, West Virginia; and DOVERPHOS S-9228
produced by Dover Chemical Corp. of Dover, Ohio. Preferably, the
antioxidant(s) comprise
no more than about 1.0% by weight of the heat-retentive material.
[0044] Structural and/or thermal conductivity materials, such as, for example,
chopped glass
fiber, glass particles, carbon powders, carbon fibers, and the like, may also
be added to the
polyethylene resin in amounts up to about 30% by weight of the heat-retentive
material by
compounding, or the like. Chopped glass fiber, for example, imparts structural
strength to the
heat-retentive material when heated above the melting point of the
polyethylene resin. A
suitable chopped glass fiber is 415A CRATEC chopped glass strands, available
from
Owens Corning, which are particularly formulated to optimize glass/polymer
adhesion.
[0045] Low density polyethylene and linear low density polyethylene resins
incorporating
carbon powder such as MPC Channel Black produced by Keystone Aniline
Corporation of
Chicago, Illinois, and XPB-090 produced by Degussa Chemicals of Akron, Ohio,
exhibit not
only improved structural integrity at high temperatures and improved thermal
conductivity,
but also a reduction in the oxidation rate of the polyethylene.
[0046] In summary, a particularly preferred heat-retentive material 8 is a
solid-to-solid phase
change composite having at least about 70% by weight polyethylene content and
from 0% to
about 30% by weight of additives such as antioxidants, thermal conductivity
additives,
structural additives, or the like.
[0047] While the use of a solid-to-solid phase change material as the heat-
retentive material
is preferred for prolonged heating applications, other heat-retentive
materials that store and
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release sensible heat can be used if a shorter heating period is acceptable.
Indeed, for some
applications it is not even necessary to have a heat-retentive material.
Suitable alternative
heat-retentive materials include polymers such as thermoplastics, thermoset
resins, and
elastomers, preferably, polyethylene, polypropylene, or nylon, to name a few
examples.
Preferably, the heat-retentive material has a specific heat of at least about
0.2 calories per
gram-degree Celsius; more preferably, at least about 0.4 calories per gram-
degree Celsius;
and most preferably, at least about 0.5 calories per gram-degree Celsius. As
used, herein, the
term "heat-retentive material" means a polymeric material that has a specific
heat of at least
about 0.2 calories per gram-degree Celsius, preferred examples of which are
mentioned
above.
[0048] The insulating layer 24 provides a surface that will remain cool to the
touch, while
also limiting the dissipation of heat from the heat storage unit 2 to the
ambient surroundings.
Preferably, the insulating layer 24 includes an inner layer of insulating
material adjacent to an
outer shell layer. The inner layer of insulating material is designed to
withstand the
maximum temperatures of the heat-retentive material 8 (if used) and the
heatable element 10,
while at the same time providing a high insulative value so as to prevent the
surface of the
adjacent outer shell layer from becoming too hot. Many known fiber, foam, or
non-woven
insulating materials may be used for this inner layer. Examples of preferred
insulating
materials include MANNIGLASS V1200 and V1900, available from Lydall of Troy,
New
York. Many known types of plastic materials, such as, but not restricted to,
polypropylene,
polyethylene, various engineered resins, and acrylonitrile butadiene styrene
("ABS"), can be
used to construct the outer layer of the insulating shell layer 24.
[0049] Next, several preferred embodiments of our invention are described
below. It should
be understood, however, that various features of each of these embodiments
could be added,
omitted, and/or combined in different ways depending on the particular
features desired.
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First Embodiment
[0050] A first preferred embodiment of our invention is described below with
reference to
FIGS. 1A-1G. In this embodiment, the heat storage unit 2 is configured as a
removable,
cordless cartridge that can be used with each of a plurality of different
types of dispenser
assemblies. In this embodiment, the heatable element 10 is an MCM.
[0051] In operation, the heat storage unit 2 is plugged into a charging device
6. The charging
device 6 is then activated to generate a high-frequency alternating magnetic
field F, which
causes eddy current heating, hysteresis heating, resistive heating, or a
combination of these
types of heating along the path of the constrained induced current. The heat-
retentive
material 8 absorbs and retains the heat generated by the heatable element,
thereby energizing
the heat storage unit 2. Once charged, the heat storage unit 2 can be removed
from the
charger and installed in any one of a number of different dispensers, such as
those shown in
FIGS. IF and 1G. The heat storage unit 2 then dissipates heat stored in the
heatable element
10 and the heat-retentive material 8 (if used) to the flowable product.
Depending on the
particular application, the heat storage unit 2 can be configured to retain
its charge anywhere
from several minutes to several hours. One skilled in the art will readily
understand that the
heat-retentive ability of the heat storage unit 2 will largely depend on the
size and
arrangement of the heatable element 10, the heat-retentive material 8 (if
any), and the
insulating shell 24.
[0052] The heat storage unit 2 of the first embodiment may be configured in a
variety of
different ways, a few of which are illustrated by FIGS. lA-1D. One of ordinary
skill in the
art will, of course, recognize that the arrangement and size of the heatable
element 10 and, if
used, the heat-retentive material 8 can be varied depending on the desired
heating parameters
such as maximum temperature, heat retention time, and energizing time, and the
desired
flowable product dispensing capabilities such as dispensing rate and quantity.
[0053] In a first variation of the first embodiment, shown in FIG. IA, the
heatable element 10
and the heat-retentive material 8 are formed together as a uniform mixture of
heatable and
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heat-retentive material. The exterior of the unitary heatable element 10 and
the heat-retentive
material 8 mixture is coated with an insulating layer 24. A circuitous passage
12 is formed
through the heat storage unit 2 and defines a long flow path for the flowable
product during
dispensing. An inlet 16 and an outlet 18 are formed at opposite ends of the
passage 12. The
length of the circuitous passage 12 provides a large interface between the
heat storage unit 2
and the flowable product, thereby allowing heat to be rapidly transferred to
the flowable
product. Preferably, the passage 12 is at least twice as long as any dimension
of the heat
storage unit 2. Since heat can rapidly be transferred to the flowable product
as it flows
through the passage 12, the heat storage unit 2 is able to provide "point of
use" heating. That
is, the heat storage unit 2 of this configuration is able to heat the flowable
product at
essentially the same rate it is dispensed.
[0054] In this arrangement, the heatable material and heat-retentive material
are preferably
both moldable materials such as, for example, BMC 940 graphite-filled polymer
material and
solid-to-solid phase change composite material, respectively. A method of
manufacturing the
heat storage unit 2 of this first variation is described with reference to
FIG. 7. First, in step
701, the heatable material and the heat-retentive material are mixed. The
mixture of the
heatable material and the heat-retentive material may be accomplished by a
separate mixing
process, or alternatively, the two materials could simply be allowed to mix as
they are being
injected into the molds. Next, in steps 703a and 703b, the heat storage unit 2
is molded in
two separate halves. Each half of the heat storage unit 2 is molded with half
of the contour of
the circuitous passage 12. The first and second halves of the heat storage
unit 2 are then
ejected from their respective molds in steps 705a and 705b. The two halves of
the heat
storage unit 2 are then arranged adjacent one another and melt-bonded together
in step 707
with the passage 12 extending therethrough. In step 709, the insulating layer
24 is over-
molded about the outside of the heat storage unit 2. While the heat storage
unit 2 is
described, with reference to FIG. 7, as being formed in two halves and then
melt-bonded
together, the heat storage unit 2 could alternatively be molded as a single
unit. Moreover, the
heat storage unit 2 of this variation could be manufactured by injection
molding, compression
molding, or any other suitable molding technique.
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[0055] FIG. 1B illustrates a second variation of the first embodiment. In this
second
variation, the heat storage unit 2 is constructed similarly to the first
variation shown in FIG.
IA, except that instead of the heatable element 10 and the heat-retentive
material 8 being
formed together as a mixture of heatable and heat-retentive materials, these
two elements are
discretely formed, as described below with reference to FIG. 8. In this
variation, heatable
material is provided in step 801. In steps 803a and 803b, the heatable element
10 is molded
in two separate pieces, each piece defining half of the passage 12. The two
halves are then
ejected from their respective molds in step 805a and 805b. In step 807 the two
halves of the
heatable element 10 are assembled adjacent one another and melt-bonded
together to form
the heatable element 10 with the passage 12 formed therethrough. The heat-
retentive
material is then over-molded about the exterior of the heatable element 10 in
step 809 to form
the heat storage unit 2. The insulating layer 24 is over-molded about the
outside of the heat
storage unit 2 in step 811. In this variation, the passage 12 is configured as
a circuitous
passage, substantially the same as that depicted in FIG. lA and discussed
above. The
materials used for the heat-retentive material 8 and the heatable element 10
are preferably the
same as those discussed above with respect to FIG. IA.
[0056] In an alternative construction, the second variation of the first
embodiment could be
constructed with the heat-retentive material 8 at its interior. The method of
manufacturing
this particular alternative is described with reference to FIG. 9. In this
alternative of the
second variation, heat-retentive material is provided in step 901. In steps
903a and 903b, the
heat-retentive material 8 is molded in two separate pieces, each piece
defining half of the
passage 12. The two halves of the heat-retentive material 8 are then ejected
from their
respective molds in step 905a and 905b. In step 907, the two halves of the
heatable element
10 are joined together by, for example, melt-bonding, to form the heat-
retentive material 8
with the passage 12 formed therethrough. The heatable material is then over-
molded about
the exterior of the heat-retentive material 8 in step 909 to form the heat
storage unit 2. The
insulating layer 24 is over-molded about the outside of the heat storage unit
2 in step 911.
[0057] FIG. 1 C illustrates a third variation of the first embodiment. In this
variation, the
heat-retentive material 8 and the heatable element 10 are formed separately.
Instead of a long
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circuitous passage as in the first two variations, the passage 12 in this
variation comprises an
enlarged reservoir 20 formed in the interior of the heat storage unit 2. The
reservoir 20 has
an inlet 16 and an outlet 18 positioned at substantially opposite ends of the
reservoir 20, and
defines a flow path for the flowable product. The reservoir 20 is sized to
hold at least one
dose, and as many as five doses, of the flowable product. A "dose" of the
flowable product,
as used herein, is defined as the amount of the product typically dispensed
with each
actuation of a particular dispenser assembly. (For example, an average dose of
shaving
cream or gel is between about 5 grams and about 15 grams, while an average
dose of liquid
cleanser dispensed from a spray bottle dispenser is between about 0.5 grams
and about 1.5
grams.) This arrangement, in which only a small amount of the flowable product
is heated, is
known as "one shot" heating. In other words, a finite number of shots or doses
(at least one)
of material is heated at a given time. This type of arrangement may be
preferable when the
flowable product is to be heated to a high temperature, or when the size and
cost of the heat
storage unit 2 are considerations. Also, applications such as lotion
dispensers, spray bottles,
and shaving creams or gels, in which only a few doses of product are
successively dispensed
at one time, are particularly amenable to this type of "one shot" heating.
[0058] The heatable element 10 in the third variation comprises a number of
strips of
GRAFOIL or EGRAFTM sheeting positioned in the interior of the reservoir 20,
such that
they will be in direct contact with the flowable product contained therein. As
can be seen in
FIG. 1C, the heat-retentive material 8 is in thermal communication, but not
necessarily direct
contact, with the heatable element 10. That is, heat is transferred to the
heat-retentive
material 8 via conduction through the flowable product. FIG. 1C depicts the
heatable
element 10 as a pair of parallel strips, however, any number of strips may
effectively be used.
It should be apparent that the greater the total surface area of the strips
(as determined by the
size, shape, and number of the strips), the faster the heatable element 10
will be able to heat
the flowable product. Thus, the size, shape, and number of strips making up
the heatable
element 10 in this third variation of the first embodiment can be chosen based
on the type of
flowable product used and the desired rate of heating. Furthermore, various
other
arrangements of the heat-retentive material 8 and heatable element 10 are also
available, as
would be understood by one of ordinary skill in the art. For example, the
location of the
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heatable element 10 and the heat-retentive material 8 could be reversed, the
heatable element
and the heat-retentive material 8 could be located directly adjacent to one
another either
inside or outside the reservoir, etc.
5 [0059] FIG. 1D illustrates a fourth variation of the first embodiment. This
fourth variation is
similar to the second variation shown in FIG. 1B, except that this variation
does not include a
heat-retentive material.
[0060] Furthermore, one of ordinary skill in the art will recognize that the
"point of use" heat
10 storage units 2 shown in FIGS. IA, 1B, 1D, and 3A could also be effectively
used for "one
shot" heating by simply reducing the length of the passage 12 formed therein.
Since the heat
storage unit 2 need not heat the flowable product as fast as it is dispensed
in a "one shot"
system, the passage need only be long enough to accommodate one dose or shot
of the
flowable product at a time. In this modified arrangement, the passage 12 would
function
essentially as a long, narrow version of the reservoir of FIGS. IC and 2A. By
using the
shortened passage 12 in this variation, the size of the heat storage unit 2,
and consequently
the cost, would be advantageously reduced. Conversely, if the surface area of
the heatable
elements 10 in the "one shot" heat storage units 2 of FIGS. 1C and 2A was
increased, it
would be possible to achieve a heat transfer rate sufficient for "point of
use" heating with this
type of arrangement as well. This increase in surface area of the heatable
element might be
accomplished by, for example, increasing the number of strips, making the
strips longer and
thinner, and/or making the strips corrugated or accordion-shaped.
[0061] As described above, the cartridge heat storage units 2 of the first
embodiment can be
used with various types of dispenser assemblies. FIG. IF illustrates a
cartridge heat storage
unit 2 according to the first embodiment inserted in a hand-held scrub brush
dispenser 200.
The passage 12 in the heat storage unit 2 forms part of a dispensing path of
the flowable
product through the scrub brush dispenser. The scrub brush dispenser 200 has a
container 30
for housing a flowable product, such as a cleaning solution, and an actuator
36 connected to a
pumping device (not shown) for dispensing the flowable product. When a user
depresses the
actuator 36, the flowable product is pumped from the container 30, through the
heat storage
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unit 2, and out of a dispenser exit opening (not shown) formed in the bottom
of the scrub
brush dispenser 200. Each single depression of the actuator 36 expels one dose
of the heated
flowable product.
[0062] FIG. 1G depicts a cartridge heat storage unit 2 according to the first
embodiment
inserted in a spray bottle dispenser 100. The spray bottle dispenser 100
functions similarly to
the scrub brush dispenser 200 and also includes a container 30 for holding a
flowable
product, such as a cleaning solution, and an actuator 36 connected to a
pumping device (not
shown) for dispensing the flowable product. When the actuator 36 of the spray
bottle
dispenser 100 is pressed, the flowable product is pumped from the container
30, through the
heat storage unit 2, and out of a dispenser exit opening 38 as a heated spray.
Each single
depression of the actuator 36 expels one dose of the heated flowable product.
[0063] The charging device 6 of the first embodiment, as best seen in FIG. IA,
generally
comprises an electrical plug deck 64, a circuit board 50, a magnetic field
generator 52, and a
detection device 58.
[0064] The plug deck 64 is conventional and serves to both supply power from a
standard
alternating current (A/C) wall socket S to the other electronics of the
charging device 6, and
to support the charging device 6 in the wall socket S. Alternatively, the
charging device can
be equipped with an electrical adapter cord (not shown) for connection to a
remote outlet or
to a vehicle lighter socket, or the charging device might be configured as a
battery-powered
portable or table-top unit.
[0065] When activated, the field generator 52 generates a high-frequency,
alternating
magnetic field F that induces an electromotive force ("EMF') in the heatable
element 10. In
a preferred embodiment, the EMF induced in the heatable element 10 spawns
"eddy
currents," which cause the element 10 to heat up in direct relation to the
power (I2R) of the
current through the element 10. It should be understood, however, that the
heatable element
in other embodiments of our invention can also be designed to experience Joule
heating via
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magnetically induced currents constrained to flow in a wire segment of the
heatable element
and/or to experience hysteresis heating as a result of its presence in the
magnetic field.
[0066] As shown in more detail in FIG. 6, the circuit board 50 preferably
includes (i) a
rectifier 54 for converting alternating current from the wall outlet to direct
current, (ii) a
solid-state inverter 68, coupled to the rectifier 54, for converting the
direct current into
ultrasonic frequency current for powering the field generator 52 (preferably
from about 20
kHz to about 100 kHz), and (iii) a microprocessor-based control circuit 56,
including a
microprocessor operably coupled with the inverter 68 for control thereof. The
control circuit
56 may also include a circuit parameter sensor 70 coupled with the control
circuit 56 for
measuring a parameter related to or dependent on the load experienced by the
circuit. This
parameter sensor 70 can be, for example, a current sensor within the inverter
68 that
measures current through one of the inverter's switching transistors. An
indicator light 62
can also be provided to signal, for example, when the field generator 52 is
activated and/or
when the heat storage unit 2 is fully charged.
[0067] Preferably, the field generator 52 comprises a copper-based induction
coil that is
either printed on or otherwise applied to the circuit board 50. The field
generator 52 could
alternatively be comprised of other metal or alloy wires or coils that
generate a magnetic field
when alternating current is passed through them, and may be embodied as a
separate element
from the circuit board 50, as shown in the drawing figures. Induction coils
can have either
flat or curved configurations, but a cylindrical coil is preferred because it
provides the most
efficient heating. Preferably, the induction coil is positioned such that when
the heat storage
unit 2 is docked with the charging device 6, the distance between the
induction coil and the
heatable element 10 is less than about 0.7 cm. Larger distances can be used,
but will require
more power to be supplied to the induction coil to generate a magnetic field
large enough to
heat the heatable element 10, since the required power is proportional to the
square of the
distance between the coil and the heatable element.
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[0068] As described above, the magnetic field is generated external to the
heat storage unit 2,
i.e., by the charging device 6, and the heat storage unit 2 does not itself
include any
components for generating the magnetic field. Alternatively, the induction
coil 52 can be
incorporated within the body of the heat storage unit 2, in fixed proximity to
the heatable
element 10, as shown in FIG. 4E. Opposite ends of the induction coil 52 can be
electrically
connected to a pair of electrical contacts 28 that is accessible from the
exterior of the heat
storage unit 2. Meanwhile, the charging device 6 has a pair of corresponding
electrical
contacts 72 that, when the heat storage unit 2 is docked with the charging
device 6, provides
an electrical connection between the induction coil 52 and the plug deck 64 of
the charging
device 6.
[0069] Optionally, a radio-frequency identification ("RFID") reader or
reader/writer 58 can
also be coupled to the control circuit 56. RFID is a type of automatic
identification
technology, similar to bar code technology, except that RFID uses radio
frequency instead of
optical signals. The reader (or reader/writer) 58 produces a low-level radio
frequency
magnetic field, typically either at 125 kHz or at 13.56 MHz. This magnetic
field emanates
from the reader (or reader/writer) 58 by means of a transmitting antenna 132,
typically in the
form of a coil. Meanwhile, the heat storage unit 2 can include an RFID tag 22
(as best seen
in FIGS. 1E and 2A), which typically includes an antenna and an integrated
circuit (not
shown). The RFID tag 22 is preferably affixed to the outside of the heat
storage unit 2, such
as by adhesive, bonding, fasteners, or the like. Alternatively, the RFID tag
22 may be formed
integrally with the heat storage unit 2, such as, for example, by being molded
within a portion
of the heat storage unit 2, or applied to the container 30.
[0070] The RFID system can be either a read-only or a read/write system. Read-
only
systems, as their name suggests, permit the reader to receive information from
the tag, but not
vice versa. Read/write systems, on the other hand, permit two-way
communication between
the tag and the reader/writer, and each of these components typically includes
an electronic
memory for storing information received from the other component. The
preferred
embodiment described herein utilizes a read/write RFID system.
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[0071] In order to assure high integrity, interference-free transmissions
between the RFID tag
22 and the reader/writer 58, the control circuit 56 preferably limits
transmissions between the
tag 22 and the reader/writer 58 to times when the field generator 52 is not
generating a
magnetic field F. Some RFID systems, however, such as the TagSys C330 RFID tag
and
P031 RFID reader are able to communicate even when the field generator 52 is
generating a
magnetic field F.
[0072] The RFID tag 22 can be used to signal the reader/writer 58 whenever an
appropriate
heat storage unit 2 is placed in the charging device 6, so that the control
circuit 56 can
activate the field generator 52. Thus, the field generator 52 will not be
activated if an
improper object, or no object at all, is placed in the charging device 6.
Applying an RFID tag
22 to the container 30, instead of or in addition to the heat storage unit 2,
can prevent
charging of the heat storage unit if an inappropriate container is connected
to the heat storage
unit, or if no container is connected to the heat storage unit, thereby
enhancing the safety of
the system.
[0073] In a more advanced embodiment, the RFID tag 22 can also transmit to the
reader/writer 58 information regarding preferred heating conditions (e.g.,
heat at 180 F
(82.2 C) for five minutes, "off' for one minute, and so on) for the
particular heat storage unit
2 used. The RFID tag 22 can also be used to transmit information to the
reader/writer 58
regarding the identity of the flowable product to be used with the heat
storage unit 2, such as,
for example, a liquid cleaning solution, shaving cream or gel, lotion, or the
like, in addition to
or instead of transmitting detailed heating instructions. The control circuit
56, meanwhile,
may also include an electronic memory 134 having stored therein multiple
heating
algorithms, each one designed for heating a different type of flowable product
formulation.
Thus, whenever a heat storage unit 2 containing a particular type of flowable
product is
placed in the charging device 6, the RFID tag 22 transmits to the
reader/writer 58 the identity
of the flowable product, and the control circuit 56 initiates the appropriate
heating algorithm
for that formulation.
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[0074] Optionally, there may be provided a writable electronic memory (not
shown)
associated with the RFID tag 22. The writable electronic memory may contain
stored
information, which is periodically updated by transmissions from the
reader/writer 58, such
as information relating to the heating history of the heat storage unit 2.
This way, a real-time
clock 136 connected to the control circuit 56 can keep track of how long a
particular heat
storage unit 2 has been heated and how recently. In this manner, the control
circuit 56 can
effectively prevent overheating of the heat storage unit 2, as in the case
when the heat storage
unit 2 has not fully dissipated the heat stored therein when it is again
plugged into the
charging device 6. Instead of, or in addition to, the electronic memory, the
RFID tag may be
provided with a temperature sensor (not shown). An example of a read/write
system with
temperature sensing capability is the TagSys C330 RFID tag with an external
temperature
sensor and the accompanying P031 RFID reader, mentioned above. The temperature
sensor
can be placed in thermal communication with the portion of the heat storage
unit 2 whose
temperature is advantageously monitored during the charging process, and thus
is useful in
preventing the heat storage unit 2 from being over-charged. It is also
possible for the
temperature sensor to indicate to a user, either graphically, pictorially, or
audibly, the
temperature of the heat storage unit 2.
[0075] Alternatively, if an MiCM is used as the heatable element 10, the
charging device
may be configured to generate an electric field having a frequency in the
microwave range.
The microwave charging device could be configured either as a specialized
charging device
similar to that of FIG. 1A except having a microwave generator rather than a
magnetic field
generator, or as a conventional microwave oven.
Second Embodiment
[0076] A second preferred embodiment of our invention is described with
reference to FIGS.
2A-2C. In this embodiment, as best seen in FIG. 2A, the heat storage unit 2 is
configured as
an overcap 40 that is detachably securable to a pressurized container 30 that
contains a
flowable aerosol product. The overcap 40 and container 30 together comprise an
aerosol
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dispenser assembly 300. The overcap 40 is detachably secured to the container
30 by a
retaining lip formed in the interior of the overcap 40. In this embodiment,
the overcap 40
substantially covers the exterior of the container 30. The overcap 40 is
adapted to engage an
attachment portion 66 formed on the charging device 6 for storage and during
charging.
[0077] The heat storage unit 2 of this embodiment is configured similarly to
the third
variation of the first embodiment, discussed above and depicted in FIG. 1C.
The heat storage
unit 2 of this embodiment is configured with the heat-retentive material 8 and
the heatable
element 10 formed separately. Alternatively, the heat storage unit need not
include a heat-
retentive material. The passage 12 in this embodiment is an enlarged reservoir
20 formed in
the interior of the heat storage unit 2. The reservoir 20 has an inlet 16 and
an outlet 18
positioned at substantially opposite ends of the reservoir 20, and defines a
flow path for the
flowable product. The reservoir 20 is sized to hold at least one dose, and as
many as five
doses, of the flowable product, i.e., it is a "one shot" system as described
above. A valve
stem 34 is disposed in an opening 32 formed in the top of the container 30,
and is in
communication with the inlet 16 of the heat storage unit 2. An actuator 36 is
formed in the
overcap 40 directly above the valve stem 34. When the actuator 36 is
depressed, it in turn
depresses the valve stem 34, thereby causing flowable product to be propelled
from the
pressurized container 30, through the inlet 16, into the reservoir 20 where
the flowable
product is heated, and ultimately out the outlet 18 to be dispensed. Thus, in
this embodiment,
the reservoir 20, the inlet 16, and the outlet 18 together serve as the
passage 12 through which
the flowable product may pass.
[0078] The charging device 6 of this embodiment includes substantially the
same
components disclosed above with respect to the first embodiment, including an
electrical plug
deck 64, a circuit board 50, a magnetic field generator 52, and a detection
device 58. The
circuit board 50 includes, among other elements, a control device 56 and a
solid-state inverter
68. In this embodiment, shown in FIG. 2A, the rectifier 54 is depicted as a
separate unit,
although this arrangement is not crucial to the function of this embodiment.
The detection
device is preferably an RFID reader/writer 58 and communicates with an RFID
tag 22 in the
dispenser housing 40 in the same manner in as the first embodiment described
above.
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Furthermore, the charging device of this embodiment includes an activator
switch 60 for
manually activating the charging device 6 to begin charging the heat storage
unit 2, and an
indicator light 62 for indicating when the charging device 6 is charging. If
the RFID tag is a
passive, read-only device, then it is preferably arranged parallel to the
reader and no more
than about 3-4 cm from the antenna. Active tags, on the other hand, need not
be parallel, and
can be read/written to by the detection device 58 from significantly greater
distances.
[0079] If the charging device 6 includes both an RFID reader/writer 58 and a
manual
activator switch 60, as shown in FIG. 2A, the charging device 6 will not be
activated to
generate a magnetic field F until the RFID reader/writer 58 detects that the
dispenser
assembly 300 is placed in the attachment portion 66 and the activator switch
60 is
subsequently depressed. Thus, a user may attach the dispenser assembly 300 to
the
attachment portion 66 simply for storage. When the user is next ready to use
the dispenser
assembly 300, he or she simply has to depress the activator switch 60, thereby
activating the
charging device 6 to generate a magnetic field F to charge the heat storage
unit 2. The
charging device will notify the user by one of the previously discussed
indications (i.e., either
indicator light 62 or an audible signal) when the heat storage unit 2 is fully
charged.
Third Embodiment
[0080] A third preferred embodiment of our invention is described with
reference to FIGS.
3A and 3B. As best seen in FIG. 3A, the heat storage unit 2 is again
configured as an
overcap 40 of an aerosol dispenser assembly 300. This embodiment is similar to
the second
embodiment in many aspects. In this embodiment, however, the overcap 40 of the
dispenser
assembly 300 is smaller and fits only over the top portion of a container 30.
[0081] The heat storage unit 2 of this embodiment is permanently installed
with the housing
40 of the aerosol dispenser assembly 300 during the manufacturing process.
However, in this
embodiment, the heat storage unit 2 is configured as a "point of use" heat
storage unit, similar
to that of the first variation of the first embodiment shown in FIG. IA. The
heat storage unit
2 is constructed with the heatable element 10 and the heat-retentive material
8 formed
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together as a uniform mixture of heatable and heat-retentive material. The
exterior of the
heatable element 10 and the heat-retentive material 8 mixture is coated with
an insulating
layer 24. A circuitous passage 12 is formed through the heat storage unit 2
and defines a
long flow path for the flowable product during dispensing. An inlet 16 and
outlet 18 are
formed at opposite ends of the passage. An actuator 36 is formed in the
overcap 40 directly
above the heat storage unit 2. When the actuator 36 is depressed, it in turn
depresses the heat
storage unit 2, thereby depressing the valve stem 34 and causing flowable
product to be
propelled from the pressurized container 30, through the inlet 16, through the
circuitous
passage 12 where the flowable product is heated, and ultimately out the outlet
18 to be
dispensed.
[0082] The charging device 6 of the third embodiment is substantially similar
to that of the
second embodiment, except for the absence of a manual activation switch and
the particular
configuration of the attachment device 66. In the third embodiment, the
attachment device 66
takes the form of an arcuate support arm, which fits around the circumference
of the
container 30 to secure the dispenser assembly 300 to the charging device 6.
The charging
device 6 includes an electrical plug deck 64, a circuit board 50, a magnetic
field generator 52,
and a detection device 58. A detailed description of the various electrical
components will be
omitted since these elements have been previously discussed in detail in the
description of the
first and second embodiments.
Fourth Embodiment
[0083] A fourth preferred embodiment of our invention is described with
reference to FIGS.
4A-4E. In this embodiment, the heat storage unit 2 is configured as an overcap
40 that is
detachably securable to an aerosol container 30 that contains a flowable
product such as, for
example, shaving gel. The overcap 40 and container 30 together comprise an
aerosol
dispenser assembly 300. The overcap 40 is detachably secured to the container
30 by a
retaining lip formed in the interior of the overcap 40. The overcap 40 can be
detached from
the container 30 by pressing a release button 42. The dispenser assembly 300
of this
embodiment is used in conjunction with a charging device 6 that has an opening
through
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which the overcap 40 extends when the dispenser assembly 300 is docked with
the charging
device 6. The overcap 40 can be secured within the charging device 6 by any
suitable means,
such as, for example, the coupling assembly disclosed in commonly-assigned
U.S. Patent No.
6,415,957.
[0084] In a first variation of this embodiment, shown in FIG. 4C, the heat
storage unit 2
includes a reservoir 20 that is defined by a chamber comprising the heatable
element 10. The
heatable element 10 preferably comprises magnetically-compatible stainless
steel having a
thickness between about 0.14 cm to about 0.24 cm (about 0.055 inch to about
0.095 inch),
most preferably 430 grade stainless steel with a thickness of about 0.19 cm
(0.075 inch). A
sleeve comprising a heat-retentive material 8, preferably polyethylene having
a thickness of
about 0.25 cm (0.1 inch), lines the interior of the reservoir 20. The overcap
40 preferably
also includes an insulating shell 24 made of polypropylene, ABS, or the like.
An air gap 26
may optionally be provided between the heatable element 10 and the insulating
shell 24 to
provide additional insulation.
[0085] The reservoir 20 has an inlet 16 and an outlet 18 positioned at
substantially opposite
ends of the reservoir 20. The reservoir 20 is sized to hold at least one dose,
and as many as
five doses, of the flowable product, i.e., it is a "one shot" system. A valve
stem 34 is
disposed in flow communication with the inlet 16. The overcap 40 includes an
actuator 36
which, when depressed, causes the flowable product to be propelled from the
pressurized
container 30, through the inlet 16, into the reservoir 20 where the flowable
product is heated,
and ultimately out the outlet 18. Thus, in this embodiment, the reservoir 20,
the inlet 16, and
the outlet 18 together serve as a passage 12 through which the flowable
product may pass.
[0086] The charging device 6 of this embodiment includes substantially the
same
components disclosed above with respect to the third embodiment, including,
among other
things, a plug deck 64, a circuit board 50, an induction coil 52 for
generating a magnetic field
F, an activator switch 60, an indicator light 62, and an RFID reader (not
shown) that detects
an RFID tag (also not shown) applied to or incorporated within the overcap 40
or the
container 30.
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[0087] In operation, the charging device 6 can be activated automatically,
such as when it is
detected that the heat storage unit 2 is docked with the charging device 6, or
manually, by
pressing the activator switch 60. The indicator light 62 can, for example, be
programmed to
blink red while the heat storage unit 2 is charging, and turn green when the
heat storage unit 2
is fully charged.
[0088] The temperature to which the heatable element 10 is heated depends on
several
factors, including the desired temperature to which the flowable product is to
be heated, as
well as the structure of the heat storage unit 2. Shaving gel, for example,
preferably is heated
to a temperature of between about 49 C to about 60 C (about 120 F to about
140 F). If the
heat unit storage unit is configured as shown in FIG. 4C and described above,
this requires
heating the heatable element 10 to a temperature of between about 54 C to
about 79 C
(about 130 F to about 175 F).
[0089] A second variation of the fourth embodiment is illustrated in FIG. 4D.
In this
variation, the reservoir 20 is defined by a chamber comprising the heat-
retentive material 8,
such as polyethylene or polypropylene. The exterior of the chamber is lined by
a sleeve
comprising the heatable element 10. The chamber can be is formed by injection
molding, for
example. Alternatively, the chamber could be manufactured as an extruded
sleeve in which
the heatable element, preferably GRAFOIL sheeting, is sandwiched between
layers of the
heat-retentive material. In yet another alternative embodiment, the heatable
element
comprises a porous, mesh-like, MCM, preferably stainless steel, that is
disposed within the
chamber, which is preferably made of polyethylene. Because the mesh is porous,
the
flowable product is able to pass directly through the heatable element,
thereby enabling rapid
heating of the flowable product.
[0090] Preferably, in all of the aforementioned embodiments, the heat storage
unit 2 and
charging device 6 are configured such that the maximum distance between the
heatable
element 10 and the induction coil 52 is no more than about 0.64 cm (0.25
inch). Larger
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distances can be used, but will require a greater input of energy to the coil
to generate a field
large enough to heat the heatable element.
[0091] A third variation of the fourth embodiment is illustrated in FIG. 4E.
This variation is
similar to the embodiment shown in FIG. 4C, except that the induction coil 52
is incorporated
within the overcap 40, and corresponding electrical contacts 28 and 72 are
provided on the
overcap 40 and the charging device 6, respectively.
[0092] A fourth variation of this embodiment, which is illustrated in FIG. 4F,
is similar to the
first variation shown in FIG. 4C, except that this fourth variation does not
include a heat-
retentive sleeve.
Fifth Embodiment
[0093] A fifth preferred embodiment of our invention is described with
reference to FIGS.
5A-5C. In this embodiment, the heat storage unit 2 is configured as a
flexible, porous pad 44
that functions as a "hot sponge" for cleaning or personal care treatment
applications such as
shaving, for example. A burstable pouch 14, also known as a blister pack, is
incorporated
within the pad 44 and contains a flowable product, such as a cleaning solution
or shaving gel.
Suitable burstable pouches for use in our invention are available from Klocke
of America,
Inc., among others.
[0094] The pad 44 comprises a combination of heat-retentive and heatable
materials 8, 10.
Preferably, the pad comprises two or three layers of GRAFOIL sheeting, with
each layer
being sandwiched between a layer of a solid-to-solid phase change material.
Alternatively,
the pad could comprise flakes of the heatable material dispersed throughout
the heat-retentive
material. In still further variations, the pad could be comprised of graphite
fibers interspersed
within a woven polymer matting material, or the pad could be comprised of a
woven graphite
fiber matting material interwoven with heat-retentive polymer fibers. In still
another
alternative embodiment, a heatable material could be used without a heat-
retentive material,
either alone or preferably in combination with an insulative material.
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[0095] As with the previous embodiments, the heat storage unit 2 of FIGS. 5A-
5C is
energized using a charging device 6. The charging device 6 contains
substantially the same
functional components previously described, including, among other things, a
circuit board
50, an induction coil 52 for generating a magnetic field F, an activator
switch 60, and an
indicator light 62. In the embodiment illustrated in FIGS. 5B and 5C, the
charging device is
activated manually by pressing the activator switch 60 when the pad 44 is
docked with the
charging device 6.
[0096] In operation, the flowable product is dispensed from the pad 44 by
exerting pressure
on the pad 44, which in turn compresses the burstable pouch 14 and forces the
flowable
product out of the pouch and into the pad 44. The pad 44 is porous and
contains numerous
passages therein through which the flowable product passes. As the flowable
product makes
its way through these passages, the flowable product is warmed by the heatable
and heat-
retentive materials that make up the pad.
[0097] The entire pad 44, including the burstable pouch 14, could be made to
be disposable
once the flowable product is depleted, or the pad 44 could be reused and just
the pouch could
be replaced as needed. Alternatively, the pad need not even include a
burstable pouch, and
could be used simply by applying the flowable product directly onto the pad
prior to or
shortly after heating.
[0098] While our invention has been described with respect to several
preferred
embodiments, these embodiments are provided for illustrative purposes only and
are not
intended to limit the scope of the invention. In particular, we envision that
the various
features of the several embodiments of our invention may be combined and
modified to suit
the needs of a particular application. For example, the heat storage units of
our invention
could advantageously be used with any sort of dispenser and with any sort of
flowable
product where it is desirable to dispense the flowable product at an elevated
temperature.
Thus, other applications that might benefit from the advantages of our
invention include,
personal products, such as hair spray, hair gel, mousse, shampoo, conditioner
and the like,
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food products, such as condiments, ice cream toppings (hot fudge, caramel,
etc.), soups, and
the like, industrial products, such as paint sprayers, pressure washers, and
the like, as well as
numerous other applications. Moreover, the preferred methods described for
manufacturing
the heat storage unit of our invention are merely representative. The various
method steps
described herein can be performed in different combinations and sequences with
each other
and with other method steps not specifically described herein.
[0099] Although specific components, materials, configurations, arrangements,
etc., have
been shown and described with reference to several preferred embodiments, our
invention is
not limited to these specific examples. One of ordinary skill in the art will
realize that
various modifications and variations are possible within the spirit and scope
of our invention,
which is intended to be limited in scope only by the accompanying claims.
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