U.S. patent application number 13/133995 was filed with the patent office on 2011-10-06 for meltable fuel gas generation apparatus and methods.
Invention is credited to Raymond M. Gatt.
Application Number | 20110239539 13/133995 |
Document ID | / |
Family ID | 43607539 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110239539 |
Kind Code |
A1 |
Gatt; Raymond M. |
October 6, 2011 |
MELTABLE FUEL GAS GENERATION APPARATUS AND METHODS
Abstract
Gas generation apparatus and methods are provided, including
apparatus and methods for efficient vaporization, and optional
burning, of meltable fuels. The apparatus and methods provide
controlled generation and combustion of any low melting point
dimensionally stable combustible meltable fuel. This is preferably
accomplished by first converting the solid or semi solid meltable
fuel material into a liquid state, then into vapor, and finally
mixing with an air source or other oxidizer before combustion.
Inventors: |
Gatt; Raymond M.;
(Hummelstown, PA) |
Family ID: |
43607539 |
Appl. No.: |
13/133995 |
Filed: |
August 11, 2010 |
PCT Filed: |
August 11, 2010 |
PCT NO: |
PCT/US2010/045188 |
371 Date: |
June 10, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12709967 |
Feb 22, 2010 |
|
|
|
13133995 |
|
|
|
|
61235225 |
Aug 19, 2009 |
|
|
|
61254142 |
Oct 22, 2009 |
|
|
|
Current U.S.
Class: |
48/61 |
Current CPC
Class: |
Y02B 40/00 20130101;
F23D 11/44 20130101; Y02B 40/166 20130101; F23D 2900/05001
20130101; F23D 3/22 20130101; F23D 3/02 20130101; F23D 2700/032
20130101; F23D 3/40 20130101; F23D 2700/026 20130101; F23D 2700/023
20130101 |
Class at
Publication: |
48/61 |
International
Class: |
B01J 7/00 20060101
B01J007/00 |
Claims
1. An apparatus for generating a gas vapor state of at least one
meltable fuel, the device comprising a gas generator assembly
configured and disposed to receive a meltable fuel and to convert
at least a portion of the meltable fuel to a gas vapor state.
2. The apparatus of claim 1, wherein the gas generator assembly
includes a heat source in thermal connection with a heat transfer
element, and wherein the heat transfer element is configured and
disposed for converting a meltable fuel from a solid state to at
least a liquid state.
3. The apparatus of claim 2, wherein the apparatus comprises a fuel
reservoir configured and disposed for receiving a meltable fuel,
and wherein the heat transfer element is in thermal connection with
the fuel reservoir.
4. The apparatus of claim 1, wherein the heat transfer element is
comprised of material having a thermal conductivity of greater than
10 W/m K).
5. The apparatus of claim 2, wherein the gas generation assembly
includes at least one inlet opening for receiving meltable fuel,
and wherein the gas generation assembly is configured and disposed
to convert the meltable fuel to vapor state fuel.
6. The apparatus of claim 5, wherein the gas generation assembly
further includes at least one outlet opening for allowing the vapor
state fuel to escape from the assembly.
7. The apparatus of claim 6, wherein the outlet opening of the gas
generation assembly is configured and disposed to convey the
generated vapor state fuel to a nozzle assembly.
8. The apparatus of claim 2, wherein the heat source is a burning
wick flame.
9. The apparatus of claim 8, wherein the apparatus includes at
least one diffuser assembly configured and disposed for controlling
the amount of air available to the wick flame.
10. The apparatus of claim 9, further comprising a nozzle assembly
disposed and configured to produce a combustible mixture of vapor
state fuel and air.
11. The apparatus of claim 10, wherein the heat transfer element
includes a surrounding element.
12. The apparatus of claim 11, wherein the surrounding element
comprises a heating chamber.
13. The apparatus of claim 11, wherein the heat transfer element
comprises a material having a thermal conductivity of at least 10
W/m K.
14. The apparatus of claim 1, wherein the gas generation apparatus
is selectively operable as at least one of a stove, fumigation
device, gas lantern, and heater.
15. A gas generation apparatus comprising: a reservoir configured
for receiving a meltable fuel; a heat transfer element having an
inlet end and an outlet end, wherein said inlet end is in
communicable connection with said reservoir, said heat transfer
element comprising a thermally conductive material, and a heat
source in thermal connection with the heat transfer element, the
heat source configured and disposed to transfer heat to the heat
transfer element in a sufficient amount to convert at least a
portion of a meltable fuel received by the reservoir to at least a
liquid state.
16. The apparatus according to claim 15 wherein said meltable fuel
is a wax, and wherein said heat transfer element comprises a wick
for drawing at least liquid state meltable fuel from the
reservoir.
17. The apparatus according to claim 15, wherein said apparatus is
a lamp, stove, furnace, or gas generator.
18. The apparatus according to claim 15, wherein said heat transfer
element defines a central conduit from said inlet end to said
outlet end, and wherein a capillary element is provided within said
conduit.
19. The apparatus according to claim 18, wherein said thermally
conductive material is at least as conductive as copper.
20. The apparatus of claim 19 wherein the heat source is a wick
flame.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to earlier filed U.S.
Provisional Patent Application No. 61/235,225 filed Aug. 19, 2009
and U.S. Provisional Patent Application No. 61/254,142, filed Oct.
22, 2009, as well as U.S. Utility patent application Ser. No.
12/709,967 filed Feb. 22, 2010.
[0002] Not Applicable.
BACKGROUND
[0003] Gas generation apparatus and methods are provided, including
apparatus and methods for efficient vaporization, and optional
burning, of meltable fuels.
[0004] Known fuel burning apparatus utilize various fuels such as
alcohols, kerosene, and other petroleum products in either liquid
state and/or vapor ("vapor" also referred to herein as "gas")
states. For example, portable camp stoves and heaters commonly
utilize kerosene, which in its ambient temperature, unpressurized
form is a liquid state fuel. Kerosene and other known liquid state
fuels are volatile, flammable, explosive, and sometimes corrosive,
making their transport, handling, and use inherently dangerous to a
user and the surrounding environment.
[0005] In another example, stoves, furnaces, and other combustion
apparatus are known to utilize gas state fuels such as propane,
butane, isobutane, and the like. For example, propane is provided
as a pressurized liquid that converts to gas upon release of
pressure from the tank, such as by opening a valve in a supply line
to a connected stove or heater. Liquid fuels and pressurized gas
fuels are subject to safety, health, and other regulatory
restrictions as a result of their flammable, volatile, explosive,
corrosive, and other undesirable properties. The inherent
properties of known liquid state and gas state fuels present
serious challenges in storage, transportation, and use. Commercial
transportation of such fuels is highly regulated and restricted,
requiring special permits and compliance with health and safety
laws, regulations, and procedures, such as HAZMAT, environmental,
and Homeland Security, for example. Recreational storage,
transportation, and use of known liquid and gas fuels can be just
as dangerous, and just as challenging, especially for consumers
such as hikers and campers who need to travel through commercial
governmentally regulated means such as airlines, trains, ships, and
even tunnels. For example, hikers who are traveling to remote
locations by air, with few exceptions, cannot carry pressurized
propane tanks or liquid fuel for their camp stoves. They must rely
upon the availability of such fuels at their ground
destination--which may not be available depending upon the location
and nature of the destination. Additionally, transport and use of
pressurized gas and/or liquid fuel by campers, military personnel,
or other users presents a real risk of harm by spillage and/or
leakage that can result in severe personal injury whether by flame,
explosion, ordinance, or combination thereof. For example, liquid
fuel famine relief stoves known as "panda stoves" have been banned
from importation into Africa because of the proliferation of fires
resulting from kerosene liquid fuel spillage, as well injuries
resulting from the design of such stoves. The irony of injuring a
starving person or burning down their home by providing a dangerous
stove is not lost on the author. Neither is the irony of a soldier
surviving combat conditions only to find that his liquid fuel
leaked and that he has none left for heat to survive the night. We
have a solution, as described herein.
SUMMARY
[0006] Apparatus and methods for providing safe, efficient burning
of meltable fuel are provided herein. In one embodiment, an
apparatus is provided for generating a gas vapor state of at least
one meltable fuel, the device comprising a gas generator assembly,
wherein the gas generator assembly is configured and disposed to
receive a meltable fuel and to convert the received meltable fuel
to a gas vapor state. In another embodiment, the gas generator
assembly includes a heat transfer element in communicable
connection with a heat source and a meltable fuel source.
[0007] In another embodiment, the apparatus is a gas generation
apparatus comprising a reservoir configured for receiving a
meltable fuel; a heat transfer element having an inlet end and an
outlet end, wherein said inlet end is in communicable connection
with the reservoir, the heat transfer element comprising a
thermally conductive material, in thermal connection with a heat
source, the heat source configured and disposed to transfer heat to
the heat transfer element in a sufficient amount to convert at
least a portion of a meltable fuel received by the reservoir to at
least a liquid state. Optionally, the apparatus includes a
capillary element such as a wick for drawing meltable fuel to the
heat transfer element. Optionally, the apparatus may include a heat
sink in thermal communication with the heat transfer element for
heating meltable fuel contained in a fuel reservoir. Optionally,
the heat transfer element may include an outlet for gas vapor to
escape.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an exploded perspective view of an exemplary gas
generation apparatus.
[0009] FIG. 2 is a cross-sectional perspective view of the
exemplary gas generator assembly of FIG. 1.
[0010] FIG. 3 is a side perspective view of the exemplary apparatus
of FIG. 1 in a fully assembled, closed position.
[0011] FIG. 4 is a cross-sectional perspective view of the
exemplary apparatus of FIG. 3.
[0012] FIG. 5 is a side perspective view of the exemplary apparatus
of FIG. 1 in a fully assembled, open position.
[0013] FIG. 6 is a cross-sectional side view of gas generation
apparatus.
[0014] FIG. 7 is a top perspective view of the apparatus of FIG.
6.
[0015] FIG. 8 is a cross-sectional side view of the apparatus of
FIG. 6 showing the wick flame and combustion flame.
[0016] FIG. 9 is a cross-sectional side view of another exemplary
apparatus.
[0017] FIG. 10 is a cross-sectional side view of another exemplary
apparatus.
[0018] FIG. 11 is a cross-sectional side view of another exemplary
apparatus.
[0019] FIG. 12 is a cross-sectional side view of another exemplary
apparatus.
DETAILED DESCRIPTION
[0020] Apparatus and methods for providing safe, efficient burning
of meltable fuel are provided herein. Without limitation, "meltable
fuel" as used herein includes any fuel that is substantially solid
or semi-solid at an ambient and/or room temperature and an ambient
and/or atmospheric pressure, but that converts to a liquid and/or
vapor state at an elevated temperature and/or reduced pressure. By
way of non-limiting example, meltable fuel include waxes such as
paraffin waxes, alcohol gels and other gels, flora waxes, fauna
waxes, insect waxes, animal waxes, petroleum products, alcohol and
other distillates, fats such as fauna fats, flora fats, and any
other solid or semi-solid material that is functional as a fuel,
and preferably as a combustible fuel when mixed with air or other
oxidizers. The apparatus herein are additionally and alternatively
adaptable to burning known liquid fuels such as kerosene, diesel,
alcohols, and gasolines (hereinafter collectively referred to as
"traditional liquid fuels"), by way of non-limiting example.
[0021] By way of non-limiting example, apparatus embodiments
incorporating the inventor's gas generation technology are
illustrated in FIGS. 1-9. As used herein, "stove" is intended as
non-limiting, and includes any apparatus having the claimed
elements of a gas generation apparatus, and optionally further
including a source of ignition for combustion of generated vapor,
regardless of its use. For example, the inventor contemplates that
the gas generation apparatus and the gas or vapor state fuel it
generates can be used as a stove to heat a surrounding or remote
space, such as by directing a mixture of vapor and air to an
ignition source for combustion and radiating or convecting the
resulting combustion heat to a desired area, to heat or sterilize
food and beverages for consumption, to provide light, to disperse
scents or fumigants, to power engines such as internal combustion
and/or external combustion and/or Stirling engines, among other
uses described herein and that will be apparent from study of the
instant disclosure. Additionally, it may be desirable to provide
the gas generation apparatus in the absence of an ignition and/or
combustion source, such as to provide a non-ignited gas vapor
stream to disperse scents or fumigants, for example.
[0022] The principal underlying the apparatus and methods herein
involves a gas generation cycle wherein a meltable fuel and/or
liquid fuel is converted to a gas or vapor state by the gas
generation assembly of the apparatus. In any embodiment, the
conversion is accomplished by the application of energy to the fuel
to convert the fuel from a solid state to a liquid and/or vapor
state. The energy may be provided in any number of individual or
combined forms, such as heat, light, radiation, microwaves,
electricity, energy pulses, laser, solar, and the like.
[0023] For example, in one embodiment, a meltable solid fuel
provided is melted to a liquid and/or vapor state by heat
transition from a heating assembly of the gas generation assembly.
The heating assembly includes a heat source that is selected from
any number of types, such as burning capillary member such as a
wick element, or electrical coil, radiator, or other available
energy sources. The heating assembly includes a heat transfer
element in thermal connection with the heat source, and further in
thermal connection with a meltable fuel source. The heat transfer
element is configured and disposed to be heat-conductive, and
preferably highly heat conductive at selected operating
temperatures compatible with the heat source, meltable fuel, and
other features of the apparatus and its intended uses. For example,
"highly heat conductive" as used in a paraffin wax stove embodiment
described herein means the heat transfer element has a thermal
conductivity sufficient to transfer heat from a wick flame heat
source to a paraffin wax meltable fuel in an amount sufficient to
raise the wax to a temperature above its solid-to-liquid state
melting point, e.g. to raise the wax to a temperature above
140.degree. F., for example. In other words, heat transmitted from
the heat transfer element is received by meltable fuel. For
example, the meltable fuel is preferably contained, such as in a
fuel reservoir, so that the fuel is efficiently heated by the heat
transfer element to a selected temperature, causing the meltable
fuel to change physical state(s). For example, in the example of
solid state wax fuel, the transferred heat would convert at least a
portion of the solid wax to a liquid state. In that example, the
liquid state fuel is then further heated in a controlled manner,
such as in a heating chamber, so that it is further converted to
its gas vapor state. Such heating and physical state transitions
can be selectively controlled to occur in a single fuel reservoir,
in a heating chamber, or in any combination thereof, whether as
separate or combined processes. For example, liquid state fuel in a
first fuel reservoir that is heated by a heat transfer element can
be permitted to exit the reservoir by seeping or draining through
apertures, wicks, or other communicable means to a heating chamber,
where at least a portion of the liquid state fuel is converted to a
vapor state, whether by heat, reduced pressure, capillary action,
and/or increased surface area. In one embodiment, the heating
chamber is incorporated into the heat transfer element (such as a
heated conduit, for example, as further described herein). In some
embodiments, the apparatus includes a capillary member that serves
as a means to increase the surface area of the meltable fuel
contained within the reservoir and/or heating chamber, thereby
promoting rapid transition and conveyance of a meltable fuel from a
solid state through a liquid state and eventually to a vapor state.
The capillary member may be made of any material capable of
capillary action for transporting meltable fuels in their liquid
and/or vapor states. For example, fibrous materials such as woven
or nonwoven natural or synthetic fibers and combinations thereof,
porous composite materials such as macroporous or microporous
ceramics and the like, and porous metal structures such as sintered
metal compositions, by way of non-limiting example. Preferably, the
capillary member is comprised of non-consumed materials, i.e.
materials that are not quickly degraded or easily consumed by
exposure to meltable fuels and temperatures consistent with the
apparatus and methods described herein.
[0024] Prior art teaches away from intentionally heating fuel,
whether gas or liquid, that is contained in a reservoir, such as a
reservoir in a kerosene lantern or kerosene stove, for example.
Such heating causes traditional known liquid and gas state fuels to
expand, causing undesired pressure in the reservoir that can result
in leaks. Worse, heating of known traditional liquid or gas state
fuels creates the risk of unintentionally exceeding the ignition
and/or spontaneous temperature of the fuel, creating an explosion
hazard. For those reasons, we note that prior art lanterns and
stoves are designed to ensure that any open flame is kept remote
from, and not in thermal communication with, the fuel reservoir.
For example, we note that U.S. Pat. No. 6,347,936 (the "936"
patent"), which relates to portable survival stoves using flammable
liquid fuels such as kerosene, white gas, and the like, and
discloses an integrated sealed reservoir for containing the
flammable liquid fuel. The '936 patent is representative of prior
art teachings that specifically emphasize that heat from a
combustion zone is to be thermally isolated from the fuel
reservoir. The '936 patent describes a stove wherein the "system
comprises a porous fuel wick 50 having a low thermal conductivity
retained in a feed wick shroud 52." See, '936 patent Col. 13, lines
26-28. The '936 patent further describes the wick shroud
surrounding the feed wick as "preferably constructed from a rigid,
vapor and liquid impermeable material that is non-corrosive in
liquid fuels and has a generally low thermal conductivity." See,
'936 patent at Col. 13, lines 52-56. From a further reading of the
'936 patent, it is clear that heating of the liquid fuel reservoir
is intentionally and desirably avoided. Indeed, the embodiments
described in the '936 patent expressly teach away from any transfer
of heat to the fuel reservoir. For example, in addition to the low
thermal conductivity feed wicks and wick shrouds that are in
contact with liquid fuel in the reservoir and the wick, the '936
patent instructs that the liquid fuel wick and feed assembly is
thermally insulated from a very hot "vaporization zone" by a
"substantially vapor impermeable barrier" assembly. In the
embodiments of the '936 patent, that vapor impermeable assembly
comprises a series of non-thermally conductive and low-thermally
conductive elements arranged to allow heat transfer only from a
heated plate to the adjacent surfaces of a porous member, and
specifically does not transfer heat to the wick or other liquid
feed surfaces and assemblies located beneath the porous
member--with no heat transfer suggested or motivated to reach the
fuel reservoir. For example, the '936 patent provides that "in an
embodiment preferred for use in liquid fuel combustional
applications, the substantially vapor impermeable barrier is
provided as a shroud 24, constructed from a rigid material having a
generally low thermal conductivity, and plate 26, constructed from
a rigid material having a generally high thermal conductivity. The
generally low thermal conductivity of shroud 24 is sufficiently low
to prevent a substantial portion of thermal energy from immigrating
from the vaporization zone toward liquid feed surface 12 of porous
member 14. The thermal conductivity of shroud 24 is preferably less
than about 200 watts per meter-Kelvin ("W/m K"), and more
preferably less than about 100 W/m K. The generally high thermal
conductivity of plate 26 [located between the heat source 20 and
the vaporization zone above the porous member 14] is sufficiently
high to transfer the heat required for vaporization to the
vaporization zone of the porous member. The thermal conductivity of
plate 26 is preferably greater than about 200 W/m K and more
preferably greater than about 300 W/m K. This arrangement promotes
heat transfer to and within porous member 14 in proximity to vapor
release surface 18 and vaporization zone 16, yet it advantageously
minimizes heat transfer through porous member 14 between
vaporization zone 16 and liquid feed surface 12, and into the
liquid feed system and any liquid reservoir." See, '936 patent at
Col 9, lines 37-59 (emphasis added). The '936 patent further
teaches that the porous members "preferably comprises a material
having a low thermal conductivity and a substantially uniform pore
size. The thermal conductivity of porous member 14 is preferably
sufficiently low to maintain a thermal gradient from ambient
temperature of liquid feed surface 12 to the temperature of
vaporization at vaporization zone 16, and to prevent substantial
heat transfer out of vaporization zone 16. Materials having a
thermal conductivity of less than about 10 W/m K are suitable for
porous member 14, materials having a thermal conductivity of less
than about 1.0 W/m K are preferred, and materials having a thermal
conductivity of less than about 0.10 W./m K are especially
preferred. See, '936 patent at Col. 10, lines 36-48 (emphasis
added). This arrangement promotes "thin walled Section 80 is
provided to reduce thermal conductivity of shroud 64 where it
interferes with porous member 67 thereby reducing and minimizing
heat transfer between shroud 64 through porous member 62 (emphasis
added). Stainless steel is a preferred material for shroud 64,
although many other materials having a low thermal conductivity,
such as titanium alloys, are suitable." We note that stainless
steel is generally recognized as having a thermal conductivity of
about 12 to about 45 W/m K, and that pure aluminum is generally
recognized as having a thermal conductivity of about 237 W/m K,
with aluminum alloys having a thermal conductivity of generally
between about 120 to about 180 W/m K.
[0025] Importantly, the apparatus described in the '936 patent is
not compatible or combinable with the meltable solid fuels
described herein, and does not anticipate the inventions described
herein. Indeed, the '936 patent lacks a heat transfer element in
thermal communication with a heat source and further in thermal
communication with the fuel reservoir. The low thermal conductivity
of the porous member and shroud assemblies of the 936 patent are
incompatible with the present invention. The '936 patent teachings
teach away from and prevent any significant heating of fuel placed
in the reservoir, thus preventing a meltable solid fuel from being
heated and becoming a liquid moveable by capillary or other action.
Indeed, any meltable fuel placed in the apparatus of the '936
patent will remain in its existing, ambient or room temperature
solid state, and would not liquefy or migrate to be converted to
vapor state fuel as in the present invention.
[0026] Importantly, the inventor has discovered that the use of
meltable fuels in combination with the apparatus and assemblies
described herein provides a high volume of dense vapor gas that
exceeds any known apparatus using meltable fuels, such as candles.
Indeed, even in the wick flame embodiments described herein, the
volume of dense gas vapor generated greatly exceeds the combustion
capacity of the wick flame, producing a continuous stream of excess
gas vapor that can be used for a number of purposes, including but
not limited to downstream mixing with air for combustion,
uncombusted fumigation, and as a power source for internal
combustion and/or external combustion and/or and Stirling engines,
for example.
[0027] In an example of the gas generation assembly herein, a heat
transfer element is in thermal communication with a heat source,
and is further in thermal communication with a meltable fuel
reservoir containing a meltable fuel. The heat transfer element
preferably includes at least one inlet opening for receiving heated
fuel from the reservoir, the heated fuel in a liquid and/or vapor
state. The heat transfer element in this embodiment may include one
or more heating chambers that receives heated fuel from the inlet
opening(s). The heat transfer element in this embodiment further
includes at least one outlet to permit vapor state fuel to exit the
heating chamber. Optionally, the heat transfer element may include
one or more air inlets for receiving air to mix with the heated
fuel, and/or to control the pressure within the heating chamber and
ensure that the heated fuel exits the outlet opening at a desired
rate and/or temperature. In another example, the outlet is
configured so that the exiting vapor state fuel promptly mixes with
air and therefore can be ignited to form a continuous flame. In
other embodiments, the outlet is disposed to permit the exiting
vapor to be conveyed to another combustion source, fumigation
source, storage vessel, or other gas utilization apparatus. In some
embodiments, the fuel vapor production can be increased or
supplemented, such as by utilizing a capillary element such as a
wick to pull heated fuel from the reservoir and allowing it to
evaporate to form an unignited second source of vapor fuel. As
shown and described in the figures and specification herein, for
example, such a second source of fuel vapor can be created when a
diffuser and nozzle assembly are provided in a close proximity
position to a heating element and a capillary element such as a
wick containing meltable fuel. For example, when the heating
element includes an ignited (burning) capillary wick producing a
wick flame, lowering a diffuser and nozzle assembly controllably
and desirably reduces the air supply available to the wick flame,
causing some of the liquid meltable fuel in the wick element to be
released as uncombusted dense vapor. The dense, oxygen-deprived
uncombusted gas vapor travels away from the wick element,
preferably entering into a nozzle assembly. This dense vapor can
then be selectively mixed with air in the nozzle assembly to form a
combustible mixture that can optionally be ignited to form a
combustion flame. Alternatively, the dense vapor can be selectively
directed to another destination, such as a storage tank, internal
combustion engine, fumigation area, or other apparatus or use. In
some stove embodiments shown and described herein involving a wick
flame as the heat source, a self-generated or spark-induced
combustion flame is formed distinct from the wick flame, appearing
as high as several inches above the wick flame depending upon the
air-fuel mixture characteristics provided by the diffuser and
nozzle assemblies.
[0028] As further shown and described herein, where a diffuser and
nozzle assembly is optionally provided, adjusting the diffuser
and/or nozzle position relative to a wick flame heat source can
provide adjustment of the volume of gas vapor generated by the gas
generation assembly can control the wick flame, as well as the
flame characteristics of any downstream combustion flame. The
diffuser element is preferably adjustable so that its proximity to
the heat source, such as a wick flame, can be adjusted by a user.
Moving the diffuser element closer to a heating element such as a
burning wick flame will reduce the amount of air and associated
oxygen getting to the flame, thereby reducing the intensity and
size of the wick flame. In this manner, the wick flame is caused to
emit unburned fuel vapor--not only from vapor exiting the heating
chamber, but also supplemental vapor from the heated wick proximate
the wick flame due to the lack of sufficient oxygen for combustion
as a result of the close diffuser location. Conversely, moving the
diffuser element further from the wick flame heating element allows
more air and associated oxygen to reach the wick flame causing it
to increase in size and allowing it to consume the otherwise
unburned fuel vapor emission. The inventor has observed that the
location of the diffuser and nozzle can be controlled so that the
wick flame will burn in a clean blue sphere, much like a pilot
light, generating enough heat to maintain the thermal cycle of
melting fuel and vaporizing it in the heating chamber, yet allowing
copious volumes of the generated vapor to pass through and around
the wick flame without combusting. In contrast, spacing the
diffuser and nozzle assembly far from the wick flame (or removing
the diffuser entirely) allows the wick flame to consume more vapor
fuel (whether generated from the wick or the heating chamber)--and
produces a very dirty, sooty, orange flame that lacks the heat
intensity of a downstream nozzle-controlled combustion flame in the
diffuser/nozzle examples later described herein. In other
embodiments, no diffuser is provided or necessary, because the air
flow to the wick flame is controlled by other means such as the
size of any provided gap between the capillary member and a
downstream nozzle, for example. Optionally, a porous element, such
as a mesh screen made of metal or other porous materials, can be
provided on or adjacent the outlet end of the capillary member,
such as to control the shape of the capillary member and/or the
flame. When present, the nozzle assembly is configured and disposed
to combine dense, oxygen-poor gas state fuel exiting the heating
chamber outlet (along with any dense gas vapor from the wick
element) with air containing oxygen. In stove embodiments, the
nozzle mixes the vapor with air to form a combustible mixture. The
nozzle assembly preferably includes features to direct and mix the
fuel vapor flow with air, control vapor and air flow rate, and
directing flow. The nozzle may include a converging and/or
diverging inner nozzle surface configured to contain the gas vapor
and to control its flow rate, and/or to direct flow towards a
desired location for combustion or storage. Optionally, in the
nozzle assembly, additional air is added (whether by apertures,
openings, forced air, fans, or otherwise) to the gas vapor thereby
providing an oxygen-rich, combustible mix of air and fuel for
combustion at a desired location. In other example, the nozzle can
direct air against the wick flame and/or other heat source,
altering the heat source's temperature and other properties.
Optionally, when remote combustion is desired for cooking or other
application, a combustion flame is produced downstream of the
nozzle assembly.
[0029] The apparatus and method provides the additional benefit
that when the heat source is turned off, removed, or otherwise
deactivated, the meltable fuel in the apparatus (whether in a
reservoir, heat transfer element, wick, or elsewhere) returns to
its solid or semi-solid state, making it substantially spill proof
and leak proof for storage and transport between uses. In one
example, when the wick flame is extinguished, the meltable fuel in
the wick and in the fuel reservoir returns to its normal, ambient
substantially solid or semi-solid state. This is caused by
extinguishing the wick flame and halting the transfer of heat from
the heat source to the heat transfer element, thereby halting heat
transfer to the meltable fuel reservoir, and thereby stopping the
generation of meltable fuel liquid and vapor states. The return of
the meltable fuel to substantially solid or semi-solid state makes
the apparatus spill-proof, and also substantially non-flammable if
exposed to a low-intensity flame or other ignition source. When
paraffin wax is the fuel, the fuel is non-flammable in its solid
state, and is nearly infinitely storable without degradation. Once
the thermal cycle is re-initiated by turning on the heat source,
the wax will again cycle through its liquid and vapor states
without clogging, pressurizing, priming, or other fueling activity
by the user. These features and advantages are unprecedented in
known portable camping stoves and any other combustion or gas
generation devices fueled by known liquid and/or gas fuels.
[0030] Moreover, the apparatus described herein have allowed the
inventor to reach the full thermal potential of meltable fuels.
Using the examples herein, the inventor has produced an intense,
large, hot, continuous flame of over 1400 degrees Fahrenheit. That
result shows that the inventive embodiments described herein are
harnessing the energy potential of paraffin wax, which has a
heating value of about 18,500 BTU per pound. Notably, the BTU of
liquid kerosene is nearly identical--yet cannot be achieved without
the safety hazards of spillage and explosion as described herein.
In contrast, paraffin wax has a flash point of over 250.degree. C.
(about 480.degree. F.) and solidifies to a non-combustible solid
upon cooling. Solidification begins almost immediately upon any
drip or spill from a reservoir of liquid state paraffin wax. Ask
your local manicurist or spa--people soak their hands in hot
paraffin by choice. They don't soak in kerosene.
[0031] The gas generation cycle disclosed herein, further including
apparatus for the generation of combustible mixtures of vapor and
air, is much more powerful than any existing candle-type solid fuel
apparatus. Indeed, the combustion flame produced by the apparatus
and methods herein appear to be as powerful, or more powerful, than
known catering apparatus. Such known sterno apparatus uses a
volatile jellied alcohol and produces a clear blue flame that is
dangerous if spilled fuel is ignited because it burns hot and is
difficult to spot. In contrast, the present apparatus uses meltable
solid and semi-solid fuels to avoid those undesirable risks.
Furthermore, the non-volatile, non-explosive, and waterproof nature
of meltable fuels such as waxes makes the apparatus suitable for
military use by amphibious personnel, even if exposed to gunfire
and explosions. Indeed, meltable fuels such as wax can safely be
carried on a person's body and even with food supplies without
concern. In contrast, personnel and vehicles carrying fueled stoves
using any other known liquid and gas fuel risk a significant
increased risk of exposure to flammable leaks and spills, which may
cause property damage, injury and even death. The above and other
advantages will be further evident by the following examples and
illustrations.
EXAMPLES
[0032] A first, non-limiting example of an apparatus is illustrated
in FIGS. 1-8 hereof. The apparatus embodiment shown in FIGS. 1-8
accomplish the above-described thermal fuel (and optional
combustion) cycle by the use of the elements as shown and
described. In the FIGS. 1-8, elements are described and shown
individually, and as an assembly, in both perspective and
cross-sectional views. The figures also show some exemplary shapes
and other features of the elements and assemblies, although any
number of geometric shapes and sizes of elements are contemplated
by the inventor to form additional embodiments.
[0033] Note that, although FIGS. 1-12 illustrate the examples of
the apparatus as being generally circular having a diameter of
approximately 1 inch to about 10 inches, and a height of about 2 to
about 12 inches, the apparatus can be provided in any shape or
size, and can be tuned and adjusted to provide a desired structural
rigidity, flame size, selected number of heating elements,
reservoirs, gas generator assemblies, nozzles, and other elements
to provide the desired generation of fuel vapor from a meltable
fuel (or even a traditional liquid fuel) to meet the intended
purposes of a user. Indeed, the inventor has conceived and reduced
to practice several miniaturized embodiments, without sacrificing
the heat and other performance characteristic advantages of the
invention. Exemplary apparatus have been assembled and tested, and
have provided excellent results. The assemblies have been shown to
efficiently generate vapor state fuel from meltable fuels including
paraffin, bees wax, and soy wax in accordance with the previously
described gas generation cycle, using apparatus and features
described herein. The generated vapor state fuel is rich and dense,
and requires mixing with air to be suitable for combustion.
Otherwise, the dense vapor fuel can be used for fumigation,
lubrication, deposition onto surfaces and substrates, and for any
other use appropriate for vapor state meltable fuels in their vapor
state or upon return to a liquid or solid state. When mixed with
air and ignited in an exemplary stove embodiment, the result is a
windproof, continuous wick flame and downstream combustion flame
that will boil a full cup of room-temperature water in less than 10
minutes. In stark contrast, a large candle ("candle" as used herein
is defined as a device having one or more wicks, each wick embedded
with and immediately surrounded by a mass of paraffin or other
known meltable solid fuel) was unable to boil the cup of water in
more than 30 minutes. Indeed, previous attempts to harness
significant thermal energy from candles, including multiple wick
candles, have failed.
[0034] In an exemplary embodiment shown in FIGS. 1-8, meltable fuel
130, such as paraffin wax, is received and contained in a reservoir
80 of the apparatus 10. The meltable fuel 130 can be provided by a
number of ways, including: loading a block of solid state meltable
fuel 131, into the reservoir 80 of a disassembled stove apparatus
10, then assembling the apparatus 10; pouring heated liquid
meltable fuel 132 into the reservoir 80 (whether before or after
assembly of the stove 10); and/or by inserting small wax pieces of
solid meltable fuel 131 into an opening 82 in the reservoir 80 or
reservoir lid 84. Additionally or alternatively, the lid 84 may
include a concave portion so as to permit placing of solid state
fuel 131 pieces onto the lid 84 and having the heat of the
apparatus melt the solid state fuel 131 so that it converts to
liquid state fuel 132 and drains from the lid 84 through the
opening 82 into the reservoir 80. During operation of the stove 10,
such heat may be transferred to the lid 82 from the heat transfer
element 30 and/or radiant heat from the heat source 22 (shown in
the embodiments of FIGS. 1-8 as a wick flame 26). Still further, a
gap (not shown) may be provided between the lid 84 adjacent the
heat transfer element 30 to allow melted liquid state fuel 131 to
drain from the lid 84 into the reservoir 80, such as by providing
an inward slope of the lid 84 towards the heat transfer element 30
and causing the melted wax to drain through a gap provided
therebetween. The opening 82 may be sized to enable wax sticks
(such as crayons), pellets, or other desirable and manageable forms
of meltable fuel 130 to be inserted into the reservoir 80, where
they melt by the heat of the heat transfer element 30 and by the
heat of the liquid state fuel 132 formed thereby. As shown, in one
embodiment, the heat transfer element 30 may include an enlarged
base 36, such as a disk shaped structure, to act as a heat sink
within the reservoir 80, adjacent inlet end 32 of heat transfer
element 30. In another embodiment, the opening 82 is mated to a
section of heat conductive (e.g. copper) tubing (not shown) that is
disposed in thermal contact with the heat transfer element 30
and/or liquid state fuel 132, so that the opening 82 and associated
tubing is heated and will rapidly melt inserted solid state
meltable fuel 131, such as wax crayons, to a liquid state, thereby
refilling the reservoir 80. In any of these manners, and due to the
non-pressurized and non-volatile nature of the meltable fuel 130,
the stove 10 can be safely and easily refueled even when fully
operating with the heat source 22 providing heat, and even with an
open reservoir 80, and with an optional hot continuous downstream
combustion flame 122.
[0035] When provided, a capillary element, here a wick element 40,
is preferably in thermal contact with a heat source 22, such as a
wick flame 26. The wick element 40 is also shown in thermal contact
with a heat transfer element 30, here shown as a generally
cylindrical hollow pipe. In the example shown, the desired thermal
contact and thermal transfer is accomplished by lighting the wick
member 40 at the outlet end 42 of capillary wick member 40, and
further by encasing or surrounding the lower reservoir end 44 of
the wick member 40 with a heat transfer element 30. Heat transfer
element 30 is preferably made of high heat conductive material,
preferably copper. The heat transfer element 30 may be provided as
a solid, semi-solid or hollow structure. Preferably it is hollow to
permit partial or complete surrounding of the capillary wick member
40, except for a protruding outlet end 42. The heat transfer
element 30 may additionally or alternatively include one or more
internal heat transfer elements 39. Although shown in the figures
as a divider that is plate-like and bifurcates the center chamber
38 of the heat transfer element 30, the internal heat transfer
element 39 may additionally or alternatively be any heat-conductive
or heat-retaining structure, such as a rod, tube, or other
structure in thermal contact with the internal surfaces of the wick
member 40, and/or as heat-conductive fibers woven into the wick
member 40, for example. For example, in one embodiment shown, a
first surrounding heat transfer element 30 surrounds the lower wick
portion adjacent outlet end 42, while a thin center heat transfer
element 39 shaped as a dividing plate is located in a central
hollow chamber 38, bifurcating the wick member 40 within the heat
transfer element 30. This embodiment also allows the center heat
transfer element 38 to act as a mount for the diffuser rod 54,
which in turn vertically adjustably holds the diffuser disk 52 of
the diffuser assembly 50 in a desired position relative to the wick
flame end 42 and the wick flame heat source 26.
[0036] In order to generate the gas generation cycle, a heat source
22 is needed. In the embodiment of FIGS. 1-8 and 10, the heat
source is a wick flame 26, although any source of heat or other
energy to convert meltable fuel 130 from its solid state fuel 131
to its liquid state fuel 132 and/or vapor state fuel 134 is
contemplated. In these examples, with the stove apparatus 10 in its
open position as shown in FIG. 5, it is characterized by the upper
housing 70 and fixed nozzle assembly 60 in a position slidably up
and away from the reservoir 80 and wick member 40. To light the
stove apparatus 10 in this embodiment the user inserts a match
through vents 72 provided in the upper housing 70 to reach the
outlet end 42 of the wick member 40. Once the outlet end 42 of the
wick member 40 (opposite the reservoir end 44) is lit, the lighted
end portion of wick member 40 forms a wick flame 26. The wick flame
26 causes meltable fuel 130 impregnated in the wick element 40 to
liquefy, and to gas off and burn at the surface of the wick member
40 in almost candle-like fashion. The burning at the outlet end 42
of the wick member 40 causes the heat transfer element 30
(preferably made of copper material or other highly heat conductive
material) to absorb heat from the wick flame 26. Due to the
preselected heat conductive properties of the heat transfer element
30, heat from the wick flame 26 is conducted along the entire heat
transfer element 30, reaching the reservoir end 44 adjacent the
heat transfer member inlet end 32. The inlet end 32 may be open,
and/or may include apertures 33 to permit liquid state fuel 132 to
enter a heating chamber 38 formed in the heat transfer element 30.
Heat from the heat transfer element 30 melts any solid meltable
fuel 131 in the reservoir 80 into a liquid state fuel 132, which
then freely flows into the chamber 38, whether by autogenous
pressure of the heating of the reservoir 80, capillary action of a
capillary member such as wick member 40, vacuum created from the
chamber 38 and wick flame 26, and/or combinations thereof. Once
inside the chamber 38, the liquid state fuel 132 is quickly
converted to its vapor state, whether by heat, reduced pressure,
evaporative action, or combinations thereof. The vapor state fuel
134 then exits the outlet opening 34 of the heat transfer element
30. In the embodiment of FIGS. 1-8, the outlet opening 34 is in
immediate proximity to the wick flame 26. However, as previously
described herein and as shown in FIG. 5, the closing of the stove,
by sliding upper housing 70 fully downward onto reservoir 80, also
closes the gap 90 provided between the wick member 40 adjacent the
outlet end 42 and the diffuser disk 52, restricting air flow to the
wick flame 26. This closed position results in very low,
controlled, and sustainable combustion at wick flame 26 to minimize
consumption of meltable fuel 130 by the wick flame 26, and allows
the dense vapor state fuel 134 to pass out of the outlet opening 34
and past the wick flame 26 without combusting. The diffuser disk 52
further acts to spread the vapor state fuel 134 into a broader
stream before it enters the lower portion 62 of the nozzle assembly
60. Once in the nozzle assembly 60, the gas mixes with air drawn
through the gap 90 and the apertures 66 provided in the upper
diverging portion 64 of the nozzle assembly 60 to produce a
combustible mixture of gas and air in a combustion zone 120 that
can optionally be ignited to form a downstream combustion flame 122
that appears above the diffuser disk 52.
[0037] Again, any number of heat transfer elements 30 may be
provided in thermal contact with the heat source (here a wick flame
26), with the common functional feature being that heat from the
heat source 22 is conducted to meltable fuel 130 received by the
reservoir 80 to convert the meltable fuel 130 to a vapor state fuel
134 in a controlled manner to sustain the gas generation (aka fuel
vaporization) cycle described herein. In the examples of FIGS. 1-9
and 10, heat from the heat source 22 (here a wick flame 26) is
conveyed by the heat transfer element 30 to meltable fuel 130 in
the reservoir 80. Solid state fuel 131 in the reservoir 80 is
converted by the transferred heat to a liquid state fuel 132. The
resulting liquid state fuel 132 seeps, whether under pressure or by
capillary action or otherwise, into inlet end 32 and/or apertures
33 provided in the heat transfer element 30. Once inside the heat
transfer element 30 the center conduit of the heat transfer element
acts as a heating chamber 38 to hold and heat the liquid state fuel
132 using the surrounding heated walls, capillary wicking material
40 and meltable fuel 130 in the reservoir 80 as chamber boundaries.
As a result, the liquid state fuel 132 in the heating chamber 38 is
heated to a point where it transitions to a vapor state fuel 134,
and wherein the vapor pressure of the vapor state fuel 134 exceeds
any atmospheric or other external applied pressure, allowing
generated vapor state fuel 134 to escape the heating chamber 38,
such as through outlet opening 34. In the case where the heating
chamber 38 is formed as the central conduit of the heat transfer
element 30, the vapor rises upward to the outlet opening 34
opposite the reservoir inlet end 32, and preferably adjacent the
outlet end 42 and wick flame 26. Importantly, and surprisingly, the
inventor has noted that this embodiment generates a very high
volume of dense vapor state fuel 134 that blows past the heat
source 22 (such as the wick flame 26 and/or electrical element 28)
without igniting.
[0038] Optionally, in another embodiment illustrated in FIG. 10
where the wick flame 26 is desired to fuel a combustion flame 122,
one or more air inlets 37 are provided in the heat transfer element
30 and/or reservoir 80 to introduce air at a rate sufficient to
produce a combustible mixture of vapor state fuel 134 and air
immediately adjacent the outlet end 34, allowing the wick flame 26
or other heat source 22 to ignite the mixture to produce a
combustion flame 122. For example, in such an embodiment, as the
vapor state fuel 134 travels up the heat transfer element 30,
chamber 38 wick 40 and/or vapor chamber 35, ambient air is
introduced through an air intake 37 provided in the sidewall of the
heat transfer element 30 which mixes air with the vapor state fuel
134 to produce a combustible air fuel mixture. However, in a
preferred stove embodiment, any air mixture prior to the wick flame
26 is controlled so that upon exit from the heat transfer element
30 only a small portion of the combustible mixture is ignited by
the wick flame 26 and the rest travels into a provided nozzle
assembly 60 where additional air is added before further activity,
such as ignition, to form continuous combustion flame 122. When
desirable, the diffuser disk 52 is made from a highly heat
conductive material, such as copper, by non-limiting example, so
that it can ignite or re-ignite the combustible mixture of air and
vapor state fuel 134 once adequately heated by the wick flame 26 or
other heat source 22. As shown in FIG. 1 and FIG. 10, the diffuser
disk 52 may be substantially solid, may include slots or apertures
or tabs, and may be flat, concave, convex, or finned so as to
produce the desired separation of the wick flame 26 from the
combustion zone 120, and to tune the wick flame 26 as well as the
gas and air mixture entering the nozzle 60. In cases where the disk
52 is highly heat conductive, such as comprising copper, the stove
10 is windproof in that the disk 52 will re-ignite the wick flame
26 and the combustion flame 122 by igniting the vapor gas and air
mixture that continues to spew from the apparatus 10 so long as the
chamber 38 (and optionally vapor chamber 35) is emitting vapor
state fuel 134. That period of reignition can be from milliseconds
up to several minutes. Along with fortifying the wick flame 26 by
contributing additional vapor state fuel 134, the diffuser disk 52
and nozzle apparatus 60 and other apparatus described herein
provide a method of routing and directing additional air for
efficient combustion and reduced soot output, for example.
[0039] As shown in FIG. 9, and as can be accomplished in the
apparatus of FIGS. 1-8 by removal of nozzle assembly 60, nozzle
assembly 60 is optional where an open, sooty flame is desired,
and/or when the gas vapor is not desired to be locally ignited. For
example, where the meltable fuel 130 has fumigant properties (such
as citronella wax), it may be desirable to simply allow the excess
gas vapor state fuel 134 to dissipate from the heat transfer
element 30, outlet opening 34, and/or outlet end 42 of wick member
40 in a dense stream, without igniting it, so that a surrounding
area fills with vapor, such as to mitigate against insects in a
wooded campground, greenhouse, or other space in need of
fumigation. Citronella wax mixed in the reservoir 80 or dropped
onto the lid 84 or diffuser disc 52 is suitable for this purpose,
in this embodiment and also in other embodiments.
[0040] However, in stove embodiments and other embodiments where a
combustion flame 122 is desired, a nozzle assembly 60 is provided.
Preferably, the nozzle assembly 60 is movable, such as by mounting
on the slidable upper housing 70 of the apparatus 10. Desirably,
the nozzle assembly 60 can be adjustably lowered to be placed in
close proximity to the wick 40 and any wick flame 26. In this
position, the air supply to the wick flame 26 is reduced, causing
the wick flame 26 to consume very little meltable fuel 130,
including a minimal amount of any vapor state fuel 134, and thereby
allowing the gas vapor state fuel 134 escaping from the heat
transfer element outlet 34 to pass by unignited, and further
allowing some of the meltable fuel 130 impregnated in the wick
member 40 to vaporize without igniting. Any unignited vapor state
fuel 134 then travels into the nozzle assembly 60. In the nozzle
assembly 60 additional air can be added (whether by an aperture 66,
fan, or otherwise) facilitating desirable combustion. In the closed
position of FIGS. 2, 3 and 4, the closed position of the nozzle
assembly 60 controls a gap 90 that restricts air flow to the wick
flame 26, causing the wick flame 26 to achieve a very efficient,
pilot-like clean blue appearance that keeps the gas generation
cycle of the gas generator assembly continuously churning while
burning a minimum of meltable fuel 130.
[0041] Optionally, vapor introduction and flame tuning and control
can be provided through adjustable means, as shown in the
accompanying examples of FIGS. 1-8 and 10-11. For example, as
expressly shown in FIG. 2 and FIG. 8, the distance between the wick
flame 26 adjacent the outlet end 42 and the diffuser disk 52 can be
adjustable, such as by mounting on a threaded rod 54, to allow the
diffuser disk 52 to be raised to allow more air flow through the
gap 90 to the wick flame 26 and also allowing greater air mixing
(such as at higher elevations where air is thinner) in the nozzle
assembly 60 prior to combustion by combustion flame 122, or lowered
to reduce air to the wick flame 26 (e.g. making fuel burn richer
and/or slower due to less air introduction). In examples wherein an
internal heat transfer element 39 is provided within the heat
transfer element 30, the heat transfer element 30 can be hollow or
solid, and the wicking material of any capillary element, such as
wick member 40, selected to permit vapor state gas 134 to percolate
up through the wick member 40, and/or through the chamber 38 before
reaching the outlet opening 34 and/or wick flame 26.
[0042] Some additional elements used in the present example and
attached drawings include a reservoir 80 used to enclose and hold
fuel, as well as to provide a base to the entire apparatus 10 for
placing on a surface, and allowing the upper housing 70 and
associated nozzle assembly 60 to be adjusted in relation to the
outlet end 42 of the wick member 40. Reservoir 80 provides a rigid
structure to the assembly, it is preferably strong enough to
support pots, pans, and any special use attachment etc. The
reservoir 80 and housing 70 can bear weight, yet are preferably
made of lightweight materials which can be rolled, cast, molded,
laminated or otherwise fabricated. Examples given in the
embodiments shown include, outer side walls that are upright,
spiral, perforated, or otherwise disposed. In either case, the
walls of the reservoir 80 and upper housing 70 provide support for
the apparatus 10, and contain the elements as an assembly. As shown
in other figures, the reservoir 80 may be movable relative to the
diffuser assembly 50 and nozzle assembly 60. Although not shown,
the reservoir 80 and housing 70 and other parts described herein
may include hinges, support legs, and/or other attachment means to
keep the stove parts movably or fixedly connected in desirable
positions. Further, leg members and/or bases members can be
provided to stabilize the apparatus 10 from tipping, and/or to
support pots and items to be heated in a desired proximity to the
combustion flame 122. Any such legs and/or base elements can be
retractable and/or removable to permit the device to have an
overall reduced diameter, and to fit inside small carrying means
such as cups, survival packs, and the like.
[0043] Nozzle assembly 60 and diffuser assembly 50 have a combined
effect of containing, shaping, introducing, and mixing vapor state
fuel 134 and air, optionally resulting in a controlled low soot
combustion flame 122 which can be used for cooking, heating and
other functions as desired. The assemblies 60 and 50 are preferably
adjustable, such as by connection to the upper housing 70 in a
manner so their relative positions in relation to one another and
to the heat source 22 such as wick flame 26 is adjustable. In the
example of FIG. 3, the nozzle assembly 60 includes a mounting base
66 that is fixed by inserting tabs through perforations provided in
the housing 70. Additional perforations or vents 72 may be provided
in the housing 70 to promote mixing, heat dispersion, gas
dispersion, access to the wick 40, nozzle 60, diffuser assembly 50,
and other parts of the apparatus 10.
[0044] Reservoir lid 84 provides the means to contain the meltable
fuel 130 in the reservoir 80, and to protect the meltable fuel 130,
whether as solid fuel 131, or liquid state fuel 132, from direct
and unintended contact with a user, water, or other environmental
surroundings. Further, lid 84 optionally facilitates refueling by
directing solid meltable fuel 131 to contact against the heat
transfer element 30 to promote melting to form a liquid state fuel
132. In some embodiments, the lid 84 is concave, sloped, and/or
angled to direct melted liquid state fuel 132 into the lower fuel
reservoir 80 through recessed opening 82, or another opening or gap
leading to the inside of reservoir 80.
[0045] Vapor gas generator assembly 20 with its sub assemblies 30,
40, and 50 (and in conjunction with reservoir 80 and other features
shown and described herein is configured to support continuous gas
vapor generation by utilizing the resultant heat generated at the
wick flame 26 or other heat source 22 to melt the meltable solid
fuel 131 and vaporize it. The assembly 20 also has the function of
moving melted liquid state fuel 132 from the fuel reservoir 80 by
capillary action and other forces, such as through the wick member
40 as a capillary material, to a location where it can be collected
and/or ignited. In the particular embodiments of FIGS. 1-8 and
10-11, the center chamber 38 of the heat transfer element 30 acts
as a chimney tube to trap and further heat a portion of the melted
fuel causing it to vaporize into a vapor stream and move the
resulting vapor state fuel 134 it in an upwardly direction to
emanate from the outlet opening 34 where it becomes a vaporized
fuel supply for the nozzle assembly 60 positioned above. The nozzle
assembly 60 also allows for the addition of air to the vapor stream
at various points for the purpose of providing a secondary source
of combustible air fuel mixture. Another vapor fuel source for the
nozzle assembly 60 is produced at the wicking material surface
adjacent wick outlet end 42. The amount of vapor production in
relation to wick flame 26 consumption is regulated by moving the
nozzle 60 and diffuser assembly 50 down so as to locate it closer
to the wick member 40 outlet end 42, effectively blocking, or
damping off, some of the combustion air supply to the wick flame 26
causing a very distinct stream of vapor to gas off the wick outlet
end 42 without being ignited by wick flame 26. In other
embodiments, such as in FIGS. 9 and 12, no diffuser is provided or
necessary, because the air flow to the wick flame 26 is controlled
by other means such as the size of any provided gap 90, for
example. Optionally, a porous element, such as a mesh screen made
of metal or other porous materials, can be provided on or adjacent
the outlet end 42 of the wick member 40, to control the shape of
the wick member and/or the flame 26, and/or to retain and/or
conduct heat to or away from the flame 26, the wick outlet end 42
and/or the heat transfer element 30.
[0046] Optionally, the apparatus 10 and gas generation assembly 20
can include features to permit pressurization of the meltable fuel
130 in the reservoir 80 and/or chamber 38 and secondary chamber 35,
with fantastic results in flame intensity and length. Exemplary
pressurization apparatus can be provided by, for example, applying
an air source to opening 84 and/or providing one or more heat
conductive chimney-like vapor chamber assembly 31 in addition to
chamber 38 and/or secondary chamber 35. In one such example shown
in FIG. 11, a narrow straw-like vapor chamber assembly 31 is
inserted down through the center of the heat transfer element 30
towards the bottom inlet end 32, the vapor chamber assembly 31
having a significantly restricted (yet open) opposite outlet end
152, which may be adjacent an outlet end 150 of secondary chamber
35 and/or outlet opening 34 of chamber 38 of heat transfer element
30. In the embodiment of FIG. 11, when the solid state fuel 131
melts, the resulting liquid state fuel 132 enters the chamber 38 of
heat transfer element 30, and the secondary chamber 35. Air and/or
vapor state fuel 134 trapped in secondary chamber 35 becomes heated
and exerts pressure on the surface of liquid state fuel 132 in
secondary chamber 35, forcing liquid state fuel in the secondary
chamber 35 into the vapor chamber assembly 31. The heat conducted
to the liquid state fuel 132 by the vapor chamber assembly 31, as
well as by the wick flame 26 and the surrounding secondary chamber
35, wick 40, and heat transfer element 30, causes at least some of
the liquid state fuel 132 in vapor chamber assembly 31 to vaporize.
The resulting pressurized vapor state fuel 134, and possibly some
liquid state fuel 132 then exits the vapor chamber assembly 31
through outlet opening 152. Optionally, the vapor chamber assembly
31 and outlet 152 can be positioned downstream of the diffuser disk
52 to allow some meltable fuel 130 to be combusted and/or vaporized
at, or downstream, of the diffuser assembly 50. Additional or
alternative pressurization may be accomplished, for example, by
pumping of air, and/or by forcing liquid state fuel 132 through
increasingly reduced channels and conduit in the reservoir 80
and/or heat transfer element 30, among other methods and apparent
from this disclosure. By way of additional example, meltable fuel
130 can be converted into a liquid state fuel 132 and pressurized
either manually (by a pumping device), by an externally powered
device or a trapped air or other pressure-inducing medium that will
naturally expand when heated (air, gas, solid substance), or
anything that has the potential to impart stored energy on the
liquid state fuel 132 in an open and/or closed version of reservoir
80, including but not limited to a spring-loaded and/or air-loaded
bellows baffle, or other known pressurizing devices. By further
example, in a closed reservoir 80 embodiment, the heat transfer
element 30 may heat any air trapped at the top of the closed
reservoir 80, causing pressure that in turn bears down on the
surface of fuel 130 in reservoir 80, forcing heated melted liquid
state fuel 132 into the inlet opening 32 and/or apertures 33,
adding to the pressure in the chamber 38, secondary chamber 35 and
ultimately the vapor chamber assembly 31.
[0047] In yet another embodiment illustrated in FIG. 12, the
apparatus includes features for introducing air and/or other
combustion-enhancing materials into the stream of gas vapor
generated by the gas generation assemblies 20 and apparatus 10. For
example, the inventor has found that providing a supply of focused
air to a location downstream of the wick flame 26 significantly
enhances the combustion flame 122. In the example shown in FIG. 12,
the apparatus includes an exemplary air conduit 150 that feeds air,
whether pressurized or ambient (such as by convection or thermal
draw) to a location for mixing with generated vapor gas 134. For
example, as shown in FIG. 10, the location can be a downstream
combustion zone 120. The air conduit 150 includes a feed end 152
that may be open to the ambient environment, or may be communicably
attached to a source of air or other combustion-enhancing materials
compatible with the gas vapor 134 generated by the apparatus. The
air conduit 150 also includes at least one outlet 154 for conveying
air or other combustion-enhancing material introduced into the feed
end 152 to the desired location. In an efficient example of this
embodiment, the inventor found that by attaching the air conduit
feed end 152 to a low-pressure air source, and locating the outlet
end 154 slightly downstream of the wick flame 26, such as proximate
the center of the combustion flame 122, combustion flame properties
were significantly and surprisingly enhanced. For example, the
combustion flame in "passive" mode (i.e. with no forced air
provided through the air conduit 150) was nearly silent,
approximately 3 inches long and tapered from blue at the base to
yellow at about the last 1/3 of the flame length. When a low
pressure air supply was attached to feed end 152, and the outlet
end 154 was placed at the center of the combustion flame 122, the
flame 122 grew louder, shrunk in length by over 50%, narrowed, and
became pure light blue from base to tip. The inventor further
observed that the combustion flame 122 temperature increased from a
passive flame temperature of about 1330 degrees Fahrenheit to an
air-fed torch-like combustion flame 122 temperature of over
145014501460 degrees Fahrenheit In this example, the fuel was
commercially available paraffin wax labeled specified to have a
melting point of about 140 degrees Fahrenheit. The air supply was
provided by a small electrically powered compressor. Thus, in this
embodiment, the inventor has demonstrated the surprising result
that a gas torch-like flame (with appearance and flame properties
much like a pressurized propane torch) can be generated from solid
meltable fuels such as wax using the apparatus 10 and inventive
methods described herein.
[0048] While the examples herein describe a self-contained
apparatus 10 wherein the meltable fuel 130 is stored as solid state
fuel 131, heated to a liquid state fuel 132, and converted to vapor
state fuel 134 within the self-contained unit, it is contemplated
that those steps can be performed in combination with remote units,
with the liquid state fuel 132 and/or vapor state fuel 134 being
transported, such as through a pipe or other suitable gas vapor
conduit, to an ignition source for combustion. Moreover, it is
contemplated herein that the fuel state conversion may be provided
at multiple locations within or remote from the ignition source. In
this manner, a single gas generation unit may be provided with more
fuel that it can self-generate, thereby providing an increased
combustion zone 120 result, with attendantly higher thermal output
and/or light output. Moreover, the inventive concept herein is
extendable to provide multiple gas generation assemblies 20 and
apparatus 10, whether in series, parallel, or otherwise to provide
a desired gas generation result.
[0049] Moreover, it is contemplated that the adjustable mechanism
for the nozzle assembly 60 and diffuser assembly 50 position and
height can incorporate any number of adjustment means. By way of
non-limiting example, friction devices can be provided to maintain
a desired height, such as compressible material and spring metal
mounted on the nozzle assembly 60 and/or on the housing 70 and/or
reservoir 80 body. The apparatus 10 incorporates passive and
automatic apparatus, assemblies, materials, each of which are
selectable depending on variables such as shape, size, flexibility,
plasticity, hardness, heat conductivity, and other characteristics
of the material and the assembly and functions desired to be
associated therewith.
[0050] The present apparatus and methods provide controlled
generation and combustion of any low melting point dimensionally
stable combustible material. This is preferably accomplished by
first converting the solid or semi solid material into a liquid
state, then into vapor, and finally mixing with an air source or
other oxidizer before combustion. The liquid state conversion can
be accomplished by any number of energy transfer activities,
whether by heat, light, microwave, energy pulse, electricity, or
other energy source operable as a heat source, whether on-site or
remote. Once a solid meltable fuel 131 has reached a liquid state
132 and/or vapor state 134 it can be delivered to a consumption or
storage site by capillary means or any suitable means including
pumps, gravity, venturi, convection, pressure, and/or vehicles such
as compressed gases such as air etc. Desired performance
requirements such as combustion flame 120 versus fumigation will
permit selection and design of the nozzle assembly 60.
[0051] Other features novel to the apparatus and methods described
herein are provided by the new use of meltable fuels 130 as a
storable, stable, non-toxic, and non-volatile fuel source. For
example, a wax fueled heater, furnace, and/or fireplace that is
either self sustaining in a wick flame 26 embodiment or that is
electrically enabled by an electrical heat source 22 using meltable
solid fuels 130 will be safe and able to remain dormant for an
extended period of time without compromising fuel integrity or
power. Lastly, the unit can include elements not shown, including
but not limited to heater boxes to convect heat from a combustion
flame 122 to another site, and/or a mantle installed (such as in or
near the combustion zone 120) to permit operation of the apparatus
10 as a lantern. Additionally, features such as carrying handles,
legs and/or base plates for stability, wind screens or thermal
screens for absorbing or reflecting heat, and other features are
contemplated.
[0052] The above description is intended as non-limiting, and the
inventor has contemplated that any method or apparatus of using
solid wax or other meltable fuels as a fuel source that can be
liquefied and/or converted into vapor state is within the scope of
the invention. While this description is made with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope.
In addition, many modifications may be made to adapt a particular
situation or material to the teachings hereof without departing
from the essential scope. Also, in the drawings and the
description, there have been disclosed exemplary embodiments and,
although specific terms may have been employed, they are unless
otherwise stated used in a generic and descriptive sense only and
not for purposes of limitation, the scope of the claims therefore
not being so limited. Moreover, one skilled in the art will
appreciate that certain steps of the methods discussed herein may
be sequenced in alternative order or steps may be combined.
Therefore, it is intended that the appended claims not be limited
to the particular embodiment disclosed herein.
* * * * *