Title of Invention

"AN APPARATUSFOR PRODUCING POWER FROM SOURCE OF LIQUID FUEL"

Abstract The apparatus includes at least one capillary flow passage (12), said capillary flow passage having an inlet end (14) and an outlet end (16), the inlet end in fluid communication with the source of liquid fuel (F), a heat source (20) arranged along the at least one capillary flow passage, the heat source operable to heat the liquid fuel in the at least one capillary flow passage to a level sufficient to change at least a portion thereof from a liquid state to a vapor state and deliver a stream of substantially vaporized fuel from the outlet end of the at least one capillary flow passage, a combustion chamber for combusting the stream of substantially vaporized fuel and air (C), the combustion chamber in communication with the outlet end of the at least one capillary flow passage and a conversion device operable to convert heat released by combustion in the combustion chamber into mechanical or electrical power.
Full Text METHOD AND APPARATUS FOR GENERATING POWER BY COMBUSTION OF VAPORIZED FUEL
[0001] The present invention relates to a power producing
apparatus and method of use thereof. A preferred apparatus can include a liquid fueled combustion chamber supplying heat to a power conversion device outputting up to 510 kg-m/sec (5,000 watts) of mechanical and/or electrical power.
[0002] The need to. power portable electronics equipment,
communications gear, medical devices and other equipment in remote
field service has been on the rise in recent years, increasing the demand
for highly efficient, mobile power systems. These applications require
power sources that provide bnth high power and energy density, while also
requiring minimal size and weight, low emissions and cost.
[0003] To date, batteries have been the principal means for
supplying portable sources of power. However, due to the time required
for recharging, batteries have proven inconvenient for continuous use
applications. Moreover, portable batteries are generally limited to power
production in the range of several milliwatts to a few watts and thus cannot
address the need for significant levels of mobile, lightweight power
production.
[0004] Small generators powered by internal combustion engines,
whether gasoline- or diesel-fueled have also been used. However, the noise and emission characteristics of such generators have made them wholly unsuitable for a wide range of mobile power systems and unsafe for indoor use. While conventional heat engines powered by high energy density liquid fuels offer advantages with respect to size, thermodynamic scaling and cost considerations have tended to favor their use in larger power plants.
[0005] In view of these factors, a void exists with regard to power
systems in the size range of approximately 5.1 to 51 kg-m/sec (50 to 500
watts). Moreover, in order to take advantage of high energy density liquid fuels, improved fuel preparation and delivery systems capable of low fueling rates are needed. Additionally, such systems must also enable highly efficient combustion with minimal emissions.
[0006] A combustion device wherein fuel is atomized by an
ultrasonic atomizing device is proposed in U.S. Patent No. 5,127,822. According to this patent, atomizers have been proposed wherein fuel is supplied to a combustion chamber in fine droplets to accelerate vaporization of the fuel and reduce the combustor residence time required to achieve acceptable combustion efficiency.
[0007] U.S. Patent No. 5,127,822 patent proposes an arrangement
wherein fuel is supplied at 5 cc/min and the fuel is atomized into droplets having a Sauter Mean Diameter (SMD) of 40 urn. Other atomizing techniques are proposed in U.S. Patent Nos. 6,095,436 and 6,102,687. An ultrasonic atomizer for supplying fuel to an internal combustion engine is proposed in U.S. Patent No. 4,986,248.
[0008] U.S. Patent No. 4,013,396 proposes a fuel aerosolization
apparatus wherein a hydrocarbon fuel (e.g., gasoline, fuel oil, kerosene, etc.) is dispensed into a condensation area with the intention of forming an aerosolized fuel of relatively even sized droplets less than 1 urn in diameter.
[0009] The aerosolized fuel is intended to be mixed with air to
provide a desired air-to-fuel ratio and combusted in the combustion area of
a heating burner and a hyat 3xchanger transfers heat from the combusted
fuel to a heat-carrying medium such as air, gas or liquid.
[0010] A fuel-vaporizing device said to address problems
associated with incomplete combustion of fuel aerosols in internal combustion engines is proposed in U.S. Patent No. 5,472,645. According to U.S. Patent No. 5,472,645, because aerosol fuel droplets do not ignite and combust completely in internal combustion engines, unburned fuel residues are exhausted from the engine as pollutants such as hydrocarbons (HC), carbon monoxide (CO) and aldehydes with
concomitant production of oxides of nitrogen (NOX). The proposal of U.S.
Patent No. 5,472,645 is intended to improve combustion of aerosol fuels
by breaking liquid fuel down into an air-fluid stream of vaporized or gas-
phase elements containing some unvaporized aerosols containing
hydrocarbons of higher molecular weight, the lighter fuel distillates said to
quickly evaporate to the gas phase, mix with air and are to be fed to an
internal combustion engine while the heavier fuel portions are said to be
transformed into a gas-phase vaporized state before they exit a cyclone
vortex device and enter the intake manifold of the engine.
[0011] U.S. Patent No. 4,344,404 proposes an apparatus for
supplying aerosol fuel droplets mixed with air to an internal combustion engine or burner, the fuel droplets said to have sizes of 0.5 to 1.5µm. The liquid fuel in aerosol form is intended to be mixed with air in a air-to-fuel ratio of about 18:1 so as to produce the least CO, HC and NOX emissions from the engine.
[0012] Various devices have been proposed for heating fuels into a
vaporized fuel that is combusted by a burner. See, for example, U.S. Patent Nos. 4,193,755; 4,320,180; and 4,784,599.
[0013] U.S. Patent No. 3,716,416 discloses a fuel-metering
device intended for use in a fuel cell system. The fuel eel! system is
intended to be self-regulating, producing power at a predetermined
level. The proposed fuel metering system includes a capillary flow
control device for throttling the fuel flow in response to the power output
of the fuel cell, rather than to provide improved fuel preparation for
subsequent combustion. Instead, the fuel is intended to be fed to a fuel
reformer for conversion to H2 and then fed to a fuel cell. In a preferred
embodiment, the capillary tubes are made of metal and the capillary
itself is used as a resistor, which is in electrical contact with the power
output of the fuel cell. Because the flow resistance of a vapor is greater
than that of a liquid, the flow is throttled as the power output increases.
The fuels suggested for use include any fluid that is easily transformed
from a liquid to a vapor phase by applying heat and flows freely through
a capillary. Vaporization appears to be achieved in the manner that vapor lock occurs in automotive engines.
[0014] U.S. Patent No. 6,276,347 proposes a supercritical or near-
supercritical atomizer and method for achieving atomization or
vaporization of a liquid. The supercritical atomizer of U.S. Patent No.
6,276,347 is said to enable the use of heavy fuels to fire small, lightweight,
low compression ratio, spa k-ignition piston engines that typically bum
gasoline. The atomizer is intended to create a spray of fine droplets from
liquid, or liquid-like fuels, by moving the fuels toward their supercritical
temperature and releasing the fuels into a region of lower pressure on the
gas stability field in the phase diagram associated with the fuels, causing a
fine atomization or vaporization of the fuel. Utility is disclosed for
applications such as combustion engines, scientific equipment, chemical
processing, waste disposal control, cleaning, etching, insect control,
surface modification, humidification and vaporization.
[0015] To minimize decomposition, U.S. Patent No. 6,276,347
proposes keeping the fuel below the -supercritical temperature until
passing the distal end of a restrictor for atomization. For certain
applications, heating just the tip of the restrictor is desired to minimize the
potential for chemical reactions or precipitations. This is said to reduce
problems associated with impurities, reactants or materials in the fuel
stream which otherwise tend to be driven out of solution, clogging lines
and filters. Working at or near supercritical pressure suggests that the fuel
supply system operate in the range of 21.1 to 56.2 kg/cm2 (300 to 800
psig). While the use of supercritical pressures and temperatures might
reduce clogging of the atomizer, it appears to require the use of a
relatively more expensive fuel pump, as well as fuel lines, fittings and the
like that are capable of operating at these elevated pressures.
[0016] Power conversion arrangements are proposed in U.S.
Patent Nos. 4,638,172; 5,836,150; 5,874,798; 5,932,940; 6,109,222; and 6,198,038. Of these, U.S. Patent No. 4,638,172 proposes a direct current generator operatively coupled to a small internal combustion
engine, the generator said to output between 4 volts (V) and 150
milliamperes (mA) to 110 V and over 250 mA. U.S. Patent No. 5,836,150
proposes a micro thrust and heat generator that can be used as a thrust
source for a micro machined turbo-electric generator. U .S. Patent No.
5,874,798 proposes a micro-turbine generator device wherein air is fed
into the device to generate electricity for use with portable electronic
products. U.S. Patent No. 5,932,940 proposes a micro-gas turbine
engine including a combustion chamber used to drive a microgenerator
which is intended to output 1.0 to 3.1 kg-m/sec (10 to 30 watts) of
electrical power for replacement of batteries in portable electronic
devices while producing 20 times the power for the same weight and
volume (e.g., replacing batteries for portable computers, radios,
telephones, power tools, heaters, coolers, military applications, etc.).
U.S. Patent No. 6,109,222 patent proposes a micro heat engine that is
intended to generate 1.0 to 3.1 kg-m/sec 10 to 30 watts of electrical
power wherein a free piston is reciprocated by a periodic combustion
process.
[0017] In one aspect, the present invention is directed to an
apparatus for producing power from a source of liquid fuel, comprising:
(a) at least one capillary flow passage, said at least one
capillary flow passage having an inlet end and an outlet end, said inlet
end in fluid communication with the source of liquid fuel;
(b) a heat source arranged along said at least one
capillary flow passage, said heat source operable to heat the liquid fuel in
said at least one capillary flow passage to a level sufficient to change at
least a portion thereof from a liquid state to a vapor state and deliver a
stream of substantially vaporized fuel from said outlet end of said at least
one capillary flow passage;
(c) a combustion chamber for combusting the stream of
substantially vaporized fuel and air, said combustion chamber in
communication with said outlet end of said at least one capillary flow
passage; and
(d) a conversion device operable to convert heat

released by combustion in said combustion chamber into mechanical and/or electrical power.
[0018] In another aspect, the present invention is directed to a
method of generating power, comprising;
(a) supplying liquid fuel to at least one capillary flow
passage;
(b) causing a stream of substantially vaporized fuel to
pass through an outlet of the at least one capillary flow passage by heating
the liquid fuel in the at least one capillary flow passage;
(c) combusting the vaporized fuel in a combustion
chamber; and
(d) converting heat produced by combustion of the
vaporized fuel in the combustion chamber into mechanical and/or electrical
power using a conversion device.
[0019] To address problems associated with the formation of
deposits during the heating of liquid fuel, another aspect of the present invention provides a method and means for cleaning deposits formed during the operation of the apparatus.
[0020] The invention will now be described in more detail with
reference to preferred forms of the invention, given only by way of
example, and with reference to the accompanying drawings, in which:
[0021] FIG. 1 presents a fuel-vaporizing device, in partial cross
section, which includes a capillary flow passage in accordance with an embodiment of the invention;
[0022] FIG. 2 shows a multi-capillary arrangement that can be used
to implement the device and system of FIG. 4;
[0023] FIG. 3 shows an end view of the device shown in FIG. 2;
[0024] FIG. 4 shows details of a device that can be used to vaporize
fuel and oxidize deposits in a multi-capillary arrangement to deliver substantially vaporized fuel for use in the practice of the present invention;
[0025] FIG. 5 shows a schematic of a control device to deliver fuel
and optionally oxidizing gas to a capillary flow passage;
[0026] FIG. 6 shows a schematic of an arrangement for using
combustion heat to preheat the liquid fuel;
[0027] FIG. 7 is a side view of another embodiment of a fuel-
vaporizing device employing a moveable rod to clean deposits from a capillary flow passage;
[0028] FIG. 7 A is a side view of the embodiment of FIG. 7 shown
with the moveable rod to clean deposits from a capillary flow passage fully engaged within the capillary flow passage;
[0029] FIG. 8 is a schematic view of an apparatus for generating
power in accordance with the invention wherein a Stirling engine is used to
generate electricity in accordance with one embodiment of the invention;
[0030] FIG. 9 s hows a p artial c ross-sectionai s chematic view o f a
power-producing device in accordance with another embodiment of the invention;
[0031] FIG. 10 is a droplet distribution graph showing percentage of
droplets as a function of droplet diameter demonstrating the benefits of the fuel vaporizing devices of the present invention;
[0032] FIG. 11 is a graph of fuel throughput versus fuel pressure for
two differently sized capillary tubes, which can be used to deliver vaporized fuel in accordance.with the invention;
[0033] FIG. 12 is a graph of gasoline mass flow as a function of time
showing the benefit to operation achieved through the use of the oxidation cleaning method of the present invention;
[0034] FIG. 13 is a graph of fuel flow rate vs. time for a commercial-
grade gasoline;
[0035] FIG. 14 presents a graph of fuel flow rate vs. time comparing
various gasolines;
[0036] FIG. 15 is a graph of fuel flow rate vs. time comparing a jet
fuel to a No. 2 diesel fuel;
[0037] FIG. 16 presents a graph of fuel flow rate vs. time for an
unadditized diesel fuel showing the effect of oxidation cleaning; and
[0038] FIG. 1 7 is a graph of fuel flow rate vs. time comparing an
unadditized diesel fuel to a diesel fuel containing an anti-fouling additive.
[0039] Reference is now made to the embodiments illustrated in
Figs. 1-17 wherein like numerals are used to designate like parts throughout.
[0040] The present invention provides a power producing apparatus
which advantageously combusts a high energy density liquid fuel. In a
preferred embodiment, the apparatus includes at least one capillary sized
flow passage connected to the fuel supply, a heat source arranged along
the flow passage to heat liquid fuel in the flow passage sufficiently to
deliver a stream of vaporized fuel from an outlet of the flow passage, a
combustion chamber in which the vaporized fuel is combusted, and a
conversion device which converts heat produced by combustion in the
combustion chamber into mechanical and/or electrical power.
[0041] The flow passage can be a capillary tube heated by a
resistance heater, a section of the tube heated by passing electrical
current therethrough. The capillary flow passage also is characterized by
having a low thermal inertia, so that the capillary passageway can be
brought up to the desired temperature for vaporizing fuel very quickly, e.g.,
within 2.0 seconds, preferably within 0.5 second, and more preferably
within 0.1 second. The capillary sized fluid passage is preferably formed
in a capillary body such as a single or multilayer metal, ceramic or glass
body. The passage has an enclosed volume opening to an inlet and an
outlet either of which may be open to the exterior of the capillary body or
may be connected to another passage within the same body or another
body or to fittings. The heater can be formed by a portion of the body such
as a section of a stainless steel tube or the heater can be a discrete layer
or wire of resistance heating material incorporated in or on the capillary
body.
[0042] The fluid passage may be any shape comprising an
enclosed volume opening to an inlet and an outlet and through which a fluid may pass. The fluid passage may have any desired cross-section with a preferred cross-section being a circle of uniform diameter. Other capillary fluid passage cross-sections include non-circular shapes such as triangular, square, rectangular, oval or other shape and the cross section of the fluid passage need not be uniform. The fluid passage can extend rectiiinearly or non-rectilinearly and may be a single fluid passage or multi-path fluid passage.
[0043] A capillary-sized flow passage can be provided with a
hydraulic diameter that is preferably less than 2 mm, more preferably
less than 1 mm, and most preferably less than 0.5 mm. The "hydraulic
diameter" is a parameter used in calculating fluid flow characteristics
through a fluid carrying element and is defined as four times the flow
area of the fluid-carrying element divided by the perimeter of the solid
boundary in contact with the fluid (generally referred to as the "wetted"
perimeter). For a tube having a circular flow passage, the hydraulic
diameter and the actual diameter are equivalent. In the case where the
capillary passage is defined by a metal capillary tube, the tube can have
an inner diameter of 0.01 to 3 mm, preferably 0.1 to 1 mm, most preferably
0.15 to 0.5 mm. Alternatively, the capillary passage can be defined by
transverse cross sectional area of the passage that can be 8 x 10-5 to 7
mm2, preferably 8 x 10-3 to 8 x 10-1 mm2 and more preferably 2 x 10-3 to 2
x 10-1 mm2. Many combinations of a single or multiple capillaries, various
pressures, various capillary lengths, amounts of heat applied to the
capillary, and different shapes and/or cross-sectional areas will suit a
given application.
[0044] The conversion device can be a Stirling engine, micro-turbine
or other suitable device for converting heat to mechanical or electrical power with an optional generator capable of producing up to about 510 kg-m/sec (5,000 watts) of power. The liquid fuel can be any type of hydrocarbon fuel such as jet fuel, gasoline, kerosene or diesel oil, an oxygenate such as
ethanol, methanol, methyl tertiary butyl ether, or blends of any of these and
the fuel is preferably supplied to the flow passage at pressures of preferably
less than 7.0 kg-m/sec (100 psig), more preferably less than 3.5 kg-m/sec (50
psig), even more preferably less than 0.7 kg-m/sec (10 psig), and most
preferably less than 0.4 kg-m/sec (5 psig). The vaporized fuel can be mixed
with air to form an aerosol having a mean droplet size of 25 urn or less,
preferably 10 µm or less, thus allowing clean and efficient ignition capabilities.
[0045] According to a preferred embodiment of the invention, liquid
fuel is delivered via a heated capillary tube (e.g., a small diameter glass,
ceramic or metallic material such as stainless steel tube having an inner
diameter of 3 mm or less) to a combustion chamber in which Lhe vaporized
fuel is mixed with preheated or unheated air. The vaporized fuel can be
mixed with air at ambient temperature, which is drawn into air supply
passages leading into the combustion chamber. Alternatively, the vaporized
fuel can be mixed with air that has been preheated such as by a heat
exchanger that preheats the air with heat of exhaust gases removed from the
combustion chamber. If desired, the air can be pressurized such as by a
blower prior to mixing with the vaporized fuel.
[0046] During vaporization of liquid fuel in a heated capillary
passage, deposits of carbon and/or heavy hydrocarbons may accumulate on the capillary walls and flow of the fuel can be severely restricted which ultimately can lead to clogging of the capillary flow passage. The rate at which these deposits accumulate is a function of capillary wall temperature, the fuel flow rate and the fuel type. While it is thought that fuel additives may be useful in reducing such deposits, should clogging develop, the fuel vaporizing device of the present invention advantageously provides a means for cleaning deposits formed during operation.
[0047] In accordance with the present invention, the air-fuel mixture is
combusted in a combustion chamber to produce heat that is converted into mechanical or electrical power. The power-producing device provides
reliable liquid fuel delivery and atomization of vaporized fuel prior to combustion.
[0048] The heated capillary flow passage has the ability to form an
aerosol of small fuel droplets (e.g., 25 urn or less, preferably 10 urn or less) when the vaporized fuel mixes with air at ambient temperature, operating at liquid fuel pressures below 7.0 kg-m/sec (100 psig), preferably less than 3.5 kg-m/sec (50 psig), more preferably less than 0.7 kg-m/sec (10 psig), and even more preferably less than 0.4 kg-m/sec (5 psig). The present invention possesses the ability to combust fuel at low air supply pressure (e.g., below 50.80 mm H2O (2 in H2O)), starts rapidly, provides for control of fouling, clogging and gumming, operates at reduced levels of exhaust emissions and requires low ignition energy to ignite the fuel-air mixture.
[0049] One advantage of the apparatus according to the invention
is its ignition energy requirement characteristics. Minimum ignition
energy is a term used to describe the ease with which an atomized
fuel/air mixture can be ignited, typically with an igniter such as a spark
ignition source. The device according to the invention can provide
vaporized fuel and/or aerosol with droplets having a Sauter Mean
Diameter (SMD) of less than 25 um, preferably less than 10 urn and
more preferably less than 5 um, such fine aerosols being useful to
improve the start-up characteristics and flame stability in gas turbine
applications. Additionally, very significant reductions in minimum ignition
energy can be achieved for fuels having values of SMD at or below 25 um.
For example, as discussed in Lefebvre, Gas Turbine Combustion
(Hemisphere Publishing Corporation, 1983) at page 252, Emin, a term that
correlates the ease with which an atomized fuel/air mixture may be ignited,
is shown to sharply decrease as SMD decreases. Minimum ignition
energy is roughly proportional to the cube of the Sauter Mean Diameter
(SMD) of the fuel droplets in the aerosol. SMD is the diameter of a
droplet whose surface-to-volume ratio is equal to that of the entire spray
and relates to the mass transfer characteristics of the spray. The
relationship between Emix and SMD for various fuels is shown in Lefebvre to be roughly approximated by the following relationship:
log Emm = 4.5(log SMD) + k; where Emin is measured in mJ,
SMD is measured in µm, and k is a constant related to fuel type.
[0050] According to Lefebyre, heavy fuel oil has a minimum ignition
energy of about 800 mJ at a SMD of 115 µm and a minimum ignition energy of about 23 mJ at a SMD of 50 urn. Isooctane has a minimum ignition energy of about 9 mJ at a SMD of 90 urn and a minimum ignition energy of about 0.4 mJ at a SMD of 40 urn. For a diesel fuel, when SMD is equal to 100 urn, Emin is about 100 mJ. A reduction in SMD to 30 urn would yield a reduction in Eminto about 0.8 mJ. As may be appreciated, ignition s ystem requirements a re substantially reduced for SMD values below 25 µm.
[0051] The power conversion a pparatus a ccording to the p resent
invention has been found to exhibit highly desirable low ignition energy
requirements. A low ignition energy requirement improves the power
producing benefits of the present invention by reducing the weight of the
overall system and maximizing the power output through the reduction of
the parasitic power losses associated with the ignition system.
[0052] !n view of the benefits hereinabove described, low energy
spark ignition devices are preferred for the igniter of the power producing
apparatus. Preferred are small piezo-electric ignition devices capable of
providing a spark energy in the range of about 5 to 7 mJ. Such devices
are known to be simple, compact and present no parasitic load issues.
The ultra-fine fuel vaporization provided by the apparatus of the invention
cooperates to provide excellent ignition characteristics with low energy
piezo-electric ignition devices.
[0053] The emissions characteristics of liquid-fueled combustion
devices a re k nown t o be sensitive to t he q uality o f t he fuel d roplet s ize distribution. High quality, fine sprays promote fuel evaporation and
enhance mixing, thereby reducing the need for fuel-rich combustion and
the often-attendant generation of smoke and soot. Small droplets follow
flow streamlines and are less prone to impact against burner walls.
Conversely, large droplets can impact burner walls and cause CO and
hydrocarbon emissions and carbon deposits. This problem is more
noticeable in devices where the flames are highly confined.
[0054] The heat produced during combustion of the vaporized fuel
can be converted to electrical or mechanical power. For instance, the heat
could be converted to any desired amount of electrical or mechanical
power, e.g., up to 510 kg-m/sec (5000 watts) of electrical power or
mechanical power. Compared to portable battery technology which can
only provide approximately 2.0 kg-m/sec (20 W) for a few hours or a noisy,
high emissions, internal combustion engine/generator producing above
102 kg-m/sec (1 kW), the apparatus according to one preferred
embodiment of the invention offers a quiet, clean power source in the few
hundred watt range.
[0055] Various technologies exist for conversion of heat produced in
the combustion chamber according to the invention into electrical or
mechanical power. For instance, in the 2.0 to 510 kg-m/sec (20 to 5000
watt) range, at least the following technologies are contemplated: Stirling
engines for conversion of heat into mechanical power which can be used
to drive a generator, micro-gas turbines which can be used to drive a
generator, thermoelectric for direct conversion of heat into electricity, and
thermophotovoltaics for direct conversion of radiant energy into electricity,
[0056] The thermoelectric devices offer advantages in terms of
being quiet and durable, and coupled with external combustion systems,
offer the potential for low emissions and flexibility as to fuel. Various types
of thermoelectric generators.which can be used as the conversion device,
include those disclosed in U.S. Patent Nos. 5,563,368; 5,793,119;
5,917,144; and 6,172.427, the disclosures of which are hereby
incorporated by reference.
[0057] The thermophotovoltaic devices offer advantages in terms of
being quiet, providing moderate power density, and coupled with external
combustion systems offer the potential for low emissions and flexibility as
to fuel. Various types of thermophotovoltaic devices, which can be used
as the conversion device, include those disclosed in U.S. Patent Nos.
5,512,109; 5,753,050; 6,092,912; and 6,204,442, the disclosures of which
are hereby incorporated by reference. As shown in U.S. Patent No.
6,204,442, a heat radiating body can be used to absorb heat from
combustion gases and heat radiated from the heat radiating body is
directed to a photocell for conversion to electricity, thus protecting the
photocell from direct exposure to the combustion gases.
[0058] Micro-gas turbines could be desirable in terms of high
specific power. Microturbine devices, which can be used as the
conversion device, include those disclosed in U.S. Patent Nos. 5,836,150;
5,874,798; and 5,932,940, the disclosures of which are hereby
incorporated by reference.
[0059] Stirling engines offer advantages with respect to size, quiet
operation, durability, and coupled with external combustion systems offer the potential for low emissions and flexibility as to fuel. Stirling engines that can be used as the conversion device will be apparent to those skilled in the art.
[0060] Referring now to FIG. 1, a fuel-vaporizing device for use in
the apparatus of the present invention is shown. Fuel vaporizing device 10, for vaporizing a liquid fuel drawn from a source of liquid fuel, includes a capillary flow passage 12, having an inlet end 14 and an outlet end 16. A fluid control valve 18 is provided for placing inlet end 14 of capillary flow passage 12 in fluid communication with a liquid fuel source F and introducing the liquid fuel in a substantially liquid state into capillary flow passage 12. As is preferred, fluid control valve 18 may be operated by a solenoid. A heat source 20 is arranged along capillary flow passage 12. As is most preferred, heat source 20 is provided by forming capillary flow passage 12 from a tube of electrically resistive
material, a portion of capillary flow passage 12 forming a heater
element when a source of electrical current is connected to the tube at
connections 22 and 24 for delivering current therethrough. Heat source
20, as may be appreciated, is then operable to heat the liquid fuel in
capillary flow passage 12 to a level sufficient to change at least a
portion thereof from the liquid state to a vapor state and deliver a
stream of substantially vaporized fuel from outlet end 16 of capillary
flow passage 20. By substantially vaporized is meant that at least 50%
of the liquid fuel is vaporized by the heat source, preferably at least 70%,
and more preferably at least 80% of the liquid fuel is vaporized.
[0061] Fuel vaporizing device 10 also includes means for cleaning
deposits formed during the operation of the apparatus of the present
invention. The means for cleaning deposits shown in FIG. 1 includes
fluid control valve 18. heat source 20 and an oxidizer control valve 26
for placing capillary flow passage 12 in fluid communication with a
source of oxidizer C. As may be appreciated, the oxidizer control valve
can be located at or near either end of capillary flow passage 12 or
configured to be in fluid communication with either end of capillary flow
passage 12. If the oxidizer control valve is located at or near the outlet
end 16 of capillary flow passage 12, it then serves to place the source
of oxidizer C in fluid communication with the outlet end 16 of capillary
flow passage 12. In operation, heat source 20 is used to heat the
oxidizer C in capillary flow passage 12 to a level sufficient to oxidize
deposits formed during the heating of the liquid fuel F. In one
embodiment, to switch from a fueling mode to a cleaning mode, the
oxidizer control valve 26 is operable to alternate between the
introduction of liquid fuel F and the introduction of oxidizer C into
capillary flow passage 12 and enables the in-situ cleaning of capillary
flow passage when the oxidizer is introduced into the at least one
capillary flow passage.
[0062] One technique for oxidizing deposits includes passing air or
steam through the capillary flow passage. As indicated, the capillary flow

passage i s p referabiy heated during the c leaning o peration s o t hat the
oxidation process is initiated and nurtured until the deposits are
consumed. To enhance this cleaning operation, a catalytic substance
may be employed, either as a coating on, or as a component of, the
capillary wall to reduce the temperature and/or time required for
accomplishing the cleaning. For continuous operation of the fuel
vaporizing device, more than one capillary flow passage can be used
such that when a clogged condition is detected, such as by the use of a
sensor, fuel flow can be diverted to another capillary flow passage and
oxidant flow initiated through the clogged capillary flow passage to be
cleaned. As an example, a capillary body can include a plurality of
capillary flow passages therein and a valving arrangement can be
provided to selectively supply liquid fuel or air to each flow passage.
[0063] Alternatively, fuel flow can be diverted from a capillary flow
passage and oxidant flow initiated at preset intervals. Fuel delivery to a
capillary flow passage can be effected by a controller. For example, the
controller can activate fuel delivery for a preset time period and
deactivate fuel delivery after the preset amount of time. The controller
may also effect adjustment'of the pressure of the liquid fuel and/or the
amount of heat supplied to the capillary flow passage based on one or
more sensed conditions. The sensed conditions may include inter alia:
the fuel pressure, the capillary temperature or the air-fuel ratio. The
controller may also control one or more capillary flow passages to clean
deposits.
[0064] The cleaning technique may be applied to combustion devices
having a single flow passage. However, if the combustion device is intermittently shut down during the cleaning operation, the energy supplied to the flow passage during cleaning would preferably be electrical. The time period between cleanings may either be fixed based upon experimentally determined clogging characteristics, or a sensing and control device may be employed to delect clogging and initiate the cleaning process as
required. For example, a control device could detect the degree of
clogging by sensing the fuel supply pressure to the capillary flow passage.
[0065] As indicated, the oxidation cleaning technique may also be
applied to fuel vaporizing devices that are required to operate
continuously. In this case, multiple capillary flow passages are
employed. An exemplary multiple capillary flow passage fuel-vaporizing
device for use in the present invention is illustrated in FIGS. 2 and 3.
FIG. 2 presents a schematic view of a multiple capillary tube
arrangement, integrated into a single assembly 94. FIG. 3 presents an
end view of the assembly 94. As shown, the assembly can include the
three capillary tubes 82A, 82B, 82C and a positive electrode 92, which
can include a solid stainless steel rod. The tubes and the rod can be
supported in a body 96 of electrically insulating material and power can
be supplied to the rod and capillary tubes via fittings 98. For example,
direct current can be supplied to upstream ends of one or more of the
capillary tubes and a connection 95 at the downstream ends thereof can
form a return path for the curent through rod 92.
[0066] Reference is made now to FIG. 4, wherein a multiple
capillary tube vaporizing system 80 for use in the practice of the present
invention is shown. The system includes capillary tubes 82A through C,
fuel supply lines 84A through C, oxidizer supply lines 86A through C,
oxidizer control valves 88A through C, power input' lines 90A-C and
common ground 91. The system 80 allows cleaning of one or more
capillary tubes while fuel delivery continues with one or more other
capillary tubes. For example, combustion of fuel via capillary flow
passages 82B and 82C can be carried out during cleaning of capillary
flow passage 82A. Cleaning of capillary flow passage 82A can be
accomplished by shutting off the supply of fuel to capillary tube 82A,
supplying air to capillary flow passage 82A with sufficient heating to
oxidize deposits in the capillary flow passage. Thus, the cleaning of
one or several capillaries can be carried out while continuously
delivering fuel. The one or more capillary flow passages being cleaned
are preferably heated during the cleaning process by an electrical
resistance heater or thermal feedback from the application. Again, the
time period between cleanings for any given capillary flow passage may
either be fixed based upon known clogging characteristics, determined
experimentally, or a sensing and control system may be employed to
detect deposit buildup and initiate the cleaning process as required.
[0067] FIG. 5 shows an exemplary schematic of a control system
to operate an apparatus in accordance with the present invention, the
apparatus incorporating an oxidizing gas supply for cleaning clogged
capillary passages. The control system includes a controller 100
operably connected to a fuel supply 102 that supplies fuel and
optionally air to a flow passage such as a capillary flow passage 104.
The controller is also operably connected to a power supply 106 that
delivers power to a resistance heater or directly to a metal capillary flow
passage 104 for heating the tube sufficiently to vaporize the fuel. If
desired, the combustion system can include multiple flow passages and
heaters operably connected to the controller 100. The controller 100
can be operably connected to one or more signal sending devices such
as an on-off switch, thermocouple, fuel flow rate sensor, air flow rate
sensor, power output sensor, battery charge sensor, etc. whereby the
controller 100 can be programmed to automatically control operation of
the combustion system in response to the signal(s) outputted to the
controller by the signal sending devices 108.
[0068] In operation, the fuel vaporizing device of the apparatus
according to the present invention can be configured to feed back heat produced during combustion such that the liquid fuel is heated sufficiently to substantially vaporize the liquid fuel as it passes through the capillary reducing or eliminating or supplementing the need to electrically or otherwise heat the capillary flow passage. For example, the capillary tube can be made longer to increase the surface area thereof for greater heat transfer, the capillary tube can be configured to pass through the
combusting fuel or a heat exchanger can be arranged to use exhaust gas from the combustion reaction to preheat the fuel.
[0069] FIG. 6 shows, in simplified form, how a capillary flow
passage 64 can be arranged so that liquid fuel traveling therethrough can
be heated to an elevated temperature to reduce the power requirements
of the fuel-vaporizing heater. As shown, a portion 66 of a tube
comprising the capillary flow passage passes through the flame 68 of the
combusted fuel. For initial start up, a resistance heater comprising a
section of the tube or separate resistance heater heated by electrical
leads 70, 72 connected to a power source such as a battery 74 can be
used to initially vaporize the liquid fuel. After ignition of the vaporized
fuel by a suitable ignition arrangement, the portion 66 of the tube can be
preheated by the heat of combustion to reduce the power otherwise
needed for continued vaporization of the fuel by the resistance heater.
Thus, by preheating the tube, the fuel in the tube can be vaporized
without using the resistance heater whereby power can be conserved.
[0070] As will be appreciated, the fuel vaporizing device and
attendant system depicted in FIGS. 1 through 6 may also be used in
connection with another embodiment of the present invention.
Referring again to FIG. 1, the means for cleaning deposits includes fluid
control valve 18, a solvent control valve 26 for placing capillary flow
passage 12 in fluid communication with a solvent, solvent control valve
26 disposed at one end of capillary flow passage 12. In one embodiment
of the apparatus employing solvent cleaning, the solvent control valve is
operable to alternate between the introduction of liquid fuel and the
introduction of solvent into capillary flow passage 12, enabling the in-situ
cleaning of capillary flow passage 12 when the solvent is introduced into
capillary flow passage 12. While a wide variety of solvents have utility,
the solvent may comprise liquid fuel from the liquid fuel source. When
this is the case, no solvent control valve is required, as there is no need
to alternate between fuel and solvent, and the heat source should be
phased-out or deactivated during the cleaning of capillary flow passage
12.
[0071] FIG. 7 presents another exemplary embodiment of the
present invention. A fuel-vaporizing device 200 for use in the apparatus of the present invention has a heated capillary flow passage 212 for delivering liquid fuel F. Heat is provided by heat source 220, which is arranged along capillary flow passage 212. As is most preferred, heat source 220 is provided by forming capillary flow passage 212 from a tube of electrically resistive material, a portion of capillary flow passage 212 forming a heater element when a source of electrical current is connected to the tube at connections 222 and 224 for delivering current therethrough,
[0072] in order to clean deposits formed during operation of fuel
vaporizing device 200, an axially moveable rod 232 is positioned through
opening 236 of end cap 234 of device body 230 so as to be-in axial
alignment with the opening of inlet end 214 of capillary flow passage
212. Packing material 238 is provided within the interior volume of end
cap 234 for sealing. Referring now to FIG. 7A, axial moveable rod 232 is
shown fully extended within capillary flow passage 212, As may be
appreciated, selecting the diameter of axial moveable rod 232 for minimal
wall clearance within the interior of capillary flow passage 212 produces
a combination capable of removing substantially all of the deposits built
up along the interior surface of capillary flow passage 212 during the
operation of fuel vaporizing device 200.
[0073] FIG. 8 shows a schematic of an apparatus in accordance
with the invention which includes a free-piston Stirling engine 30, a combustion chamber 34 wherein heat at 550-750°C is converted into mechanical power by a reciprocating piston which drives an alternator 32 to produce electrical power. The assembly also includes a capillary flow passage/heater assembly 36, a controller 38, a rectifier/regulator 40, a battery 42, a fuel supply 44, a recuperator 46, a combustion blower 48, a cooler 50, and a cooler/blower 52. In operation, the controller 38 is
operable to control delivery of fuel to the capillary 36 and to control
combustion of the fuel in the chamber 34 such that the heat of combustion
drives a piston in the Stirling engine such that the engine outputs electricity
from the alternator 32. If desired, the Stirling engine/alternator can be
replaced with a kinematic Stirling engine that outputs mechanical power.
Examples of combustion chambers and air preheating arrangements can
be found in U.S. Patent Nos. 4,277,942, 4,352,269, 4,384,457 and
4,392,350, the disclosures of which are hereby incorporated by reference.
[0074] FIG. 9 presents a partial cross-sectional schematic view of a
power-producing device in accordance with another embodiment of the
invention, which can form part of a heat conversion device such as a
Stirling engine assembly. As shown in FIG. 9, air delivered to an air inlet
by an air blower enters the combustion chamber 34 and mixes with
vaporized fuel delivered to the chamber by the capillary/heater
arrangement 36. Heat of combustion in the chamber 34 heats the end of
the Stirling engine 30 and a sliding piston reciprocates within an alternator
in a manner that generates electricity. The chamber 34 can be designed
to allow the exhaust gases to preheat incoming air and thus lower the
energy requirements for combusting the fuel. For instance, the housing
can include a multiwall arrangement, which allows the incoming air to
circulate in a plenum, which is heated by exhaust gases circulating in an
exhaust passage. Inlet air (indicated by arrow 55) can be caused to swirl
in the combustion chamber by passing the air through s wirier vanes 56
around the combustion chamber 34. The combusted air-fuel mixture heats
the heat conversion, device (Stirling engine) 30 and exhaust gases
(indicated by arrows 57) are removed from the combustion chamber.
[0075] In general, the power conversion apparatus could include a
liquid fuel source, at least one flow passage (e.g., one or more heated
capillary tubes) through which fuel from the fuel supply is vaporized and
delivered to a combustion chamber wherein the vaporized fuel is
combusted, and heat produced in the combustion chamber is used to drive
a Stirling engine or other heat conversion device. A heat exchanger can
be used to preheat air as the air travels through air passages in the heat
exchanger thereby maximizing efficiency of the device, i.e., by preheating
the air mixed with the vaporized fuel to support combustion in the
chamber, less fuel is needed to maintain the Stirling engine at a desired
operating temperature. The exhaust gas can travel through exhaust ducts
in the heat exchanger whereby heat from the exhaust gas can be
transferred to the air being delivered to the combustion chamber.
[0076] The combustion chamber can incorporate any suitable
arrangement wherein air is mixed with the vaporized fuel and/or an air-fuel mixture is combusted. For example, the fuel can be mixed with air in a venturi to provide an air-fuel mixture and the air-fuel mixture can be combusted in a heat-generating zone downstream from the venturi. In order to initiate combustion, the air-fuel mixture can be confined in an ignition zone in which an igniter such as a spark generator ignites the mixture. The igniter can be any device capable of igniting the fuel such as a mechanical spark generator, an electrical spark generator, resistance heated ignition wire or the like. The electrical spark generator can be powered by any suitable power source, such as a small battery. However, the battery can be replaced with a manually operated piezoelectric transducer that generates an electric current when activated. With such an arrangement, current can be generated electro-mechanically due to compression of the transducer. For instance, a striker can be arranged so as to strike the transducer with a predetermined force when the trigger is depressed. The electricity generated by the transducer can be supplied to a spark generating mechanism by suitable circuitry. Such an arrangement could be used to ignite the fuel-air mixture.
[0077] Some of the electrical power generated by the conversion
device can be stored in a suitable storage device such as a battery or capacitor, which can be used to power the igniter. For example, a manually operated switch can be used to deliver electrical current to a resistance-heating element or directly through a portion of a metal tube,
which vaporizes fuel in the flew passage and/or the electrical current can be supplied to an igniter for initiating combustion of the fuel-air mixture delivered to the combustion chamber.
[0078] If desired, the heat generated by combusting the fuel could
be used to operate any types of devices that rely on mechanical or
electrical power. For instance, a heat conversion source could be used to
generate electricity for portable electrical equipment such as telephone
communication devices (e.g., wireless phones), portable computers,
power tools, appliances, camping equipment, military equipment,
transportation equipment such as mopeds, powered wheelchairs and
marine propulsion devices, electronic sensing devices, electronic
monitoring equipment, battery chargers, lighting equipment, heating
equipment, etc. The heat conversion device could also be used to supply
power to non-portable devices or to locations where access to an electrical
power grid is not available, inconvenient or unreliable. Such locations
and/or non-portable devices include remote living quarters and military
encampments, vending machines, marine equipment, etc.
Examples Example 1
[0079] Tests were performed wherein JP 8 jet fuel was vaporized by
supplying the fuel to a heated capillary flow passage at constant pressure with a micro-diaphragm pump system. In these tests, capillary tubes of different diameters and lengths were used. The tubes were constructed of 304 stainless steel having lengths of 2.5 to 7.6 cm (1 to 3 in) and internal diameters (ID) and outer diameters (OD), in cm (in), as follows: 0.025 ID/0.046 OD (0.010 ID/0.018 OD), 0.033 ID/0.083 OD (0.013 ID/ 0.033 OD), and 0.043 ID/0.064 OD (0.017 ID/0.025 OD). Heat for vaporizing the liquid fuel was generated by passing electrical current through a portion of the metal tube. The droplet size distribution was measured using a Spray-Tech laser diffraction system manufactured by Malvern. FIG. 10 presents the results of tests conducted for a capillary tube of 0.025 ID/0.046 OD
(0.010 ID/0.018 OD). As shown, results of these tests revealed droplets
having a Sauter Mean Diameter (SMD) of between 1.7 and 3.0 um. SMD
is the diameter of a droplet whose surface-to-volume ratio is equal to that
of the entire spray and relates to the spray's mass transfer characteristics.
[0080] The apparatus according to the present invention also
produced measurable single and bimodal spray distributions.
Measurements revealed a single mode SMD of 2.3 µm and bimodal SMD
of 2.8 µm, the 'single mode providing aerosol droplet sizes of mostly
between 1.7 and 4.0 um whereas the bimodal spray distribution provided
80% or more of the aerosol droplets in the range of 1.7 to 4.0 um with the
remainder of droplet sizes in the range of 95 to 300 µm.
Example 2
[0081] Tests were performed using a commercial grade gasoline
that was vaporized by supplying the fuel to a heated capillary flow passage at constant pressure with a micro-diaphragm pump system. In these tests, capillary flow passages of different diameters and lengths were used. The following table shows empirical findings for various capillary tube configurations. (Table Removed)
(
Exarnple 3
[0082] Tests were conducted to demonstrate the effect of fuel
pressure on fuel flow rate. FIG. 11 shows the measurements obtained

with various tube dimensions for various fuel throughput and fuel pressures, the (•) data points indicating a 0.043 ID cm (0.017 in ID), 7.6 cm (3 in) long tube and the (A) data points indicating a 0.010 ID, 7.6 cm (3 in) long tube. The apparatus according to the invention exhibited excellent atomization performance with desired fuel flow versus pressure loss characteristics at fuel throughputs as high as 203.9 kg-m/sec (2000 W). (JP8 fuel flow rate: 1 mg/s = 42.5 W chemical energy).
Example 4
[0083] Tests were conducted to d emonstrate the benefits of the
oxidation cleaning technique on a heated capillary flow passage using an unadditized, sulfur-free base gasoline known to produce high levels of deposit formation. The capillary flow passage employed for these tests was a 5.08 cm (2.0 in) long heated capillary tube constructed of stainless steel, having an inner diameter of 0.058 cm (0.023 in). Fuel pressure was maintained at 0.7 kg/cm2 (10 psig). Power was supplied to the capillary to achieve various levels of R/R0; where R is the heated capillary resistance and R0 is the capillary resistance under ambient conditions.
[0084] FIG. 12 presents a graph of fuel flow rate vs. time. As
shown, for this gasoline containing no detergent additive, significant clogging was experienced in a very short period of time, with a 50% loss in flow rate observed in as little as 10 minutes.
[0085] After substantial clogging was experienced, fuel flow was
discontinued and air at 0.7 kg/cm2 (10 psig) substituted. Heating was provided during this period and, in as little as one minute later, significant cleaning was achieved, with flow rates returning to prior levels.
Example 5
[0086] This example demonstrates that clogging is far less severe
in the heated capillary flow passage of Example 4, when a commercial-
grade gasoline employing an effective additive package is employed. As shown in FIG. 13, less than a 10% reduction in fuel flow rate was experienced after running the device for nearly four hours.
Example 6
[0087] To compare various gasolines and the impact of detergent
additives on clogging, five test fuels were run in the heated capillary flow passage of Example 4. The fuels tested included an unadditized base gasoline containing 300 ppm sulfur, an unadditized base gasoline containing no sulfur, the suliur-free base gasoline with a commercially available after-market additive (additive A) added and the sulfur-free base gasoline with another commercially available after-market additive (additive B) added.
[0088] As shown in FIG. 14, the additized fuels performed
similarly, while unadditized fuels experienced severe clogging in less than one hour of operation.
Example 7
[0089] This example compares the operation over time of a
capillary flow passage operating on an unadditized jet fuel (JP-8) to the same capillary flow passage operating on an unadditized No. 2 diesel fuel operated in a capillary flow passage having an I.D. of 0.036 cm (0.014 in) and a 5.1 cm (2 in) length. Fuel pressure was set to 1.1 kg/cm2 (15 psig). Power was supplied to the capillary to achieve a level of R/Ro of 1.19; where R is the heated capillary resistance and R0 is the capillary resistance under ambient conditions.
[0090] As shown in FIG. 15, the fuels performed similarly over the
first ten minutes of operation, with the diesel fuel suffering more severe clogging thereafter.
Example 8
[0091] Tests were conducted to assess the efficacy of the
oxidation cleaning technique on a heated capillary flow passage using an unadditized, No. 2 diesel fuel known to produce high levels of deposit formation. The capillary flow passage employed for these tests was a 5.1 cm (2 in) long heated capillary tube constructed of stainless steel, having an inner diameter of 0.036 cm (0.014 in). Fuel pressure was maintained at 1.1 kg/cm2 (15 psig). Power was supplied to the capillary to achieve a level of R/R0 of 1.19; where R, once again, is the heated capillary resistance and R0 is the capillary resistance under ambient conditions.
[0092] FIG. 16 presents a graph of fuel flow rate vs. time. As
shown, for this fuel containing no detergent additive, significant clogging
was experienced in a very short period of time, with a 50% loss in flow
rate observed in about 35 minutes of continuous operation.
[0093] In a second run, after five minutes of operation, fuel flow
was discontinued and air at 0.7 kg/cm2 (10 psig) substituted for a period
of five minutes. Heating was also provided during this period. This
procedure was repeated every five minutes. As shown in FIG. 16, the
oxidation cleaning process increased fuel flow rate in virtually every
instance and tended to slow the overall decline in fuel flow rate over
time. However, the efficacy of the process was somewhat less than
was achieved using an unadditized gasoline, as described in Example
4.
Example 9
[0094] Tests were conducted to assess the effect of a commercial
grade anti-fouling detergent additive blended with the No. 2 diesel fuel of Example 8 on fuel flow rate over time in a heated capillary flow passage. The capillary flow passage employed for these tests, once again, was a 5.1 cm (2 in) long heated capillary tube constructed of
stainless steel, having an inner diameter of 0.036 cm (0,014 inch). Fuel
pressure was maintained at 1.1 kg/cm2 (15 psig) and power was
supplied to the capillary to achieve a level of R/R0 of 1.19.
[0095] FIG. 17 presents a comparison of fuel flow rate vs. time for
the additized No. 2 diesel fuel and an unadditized diesel fuel. As shown, for the fuel containing no detergent additive, significant clogging was experienced in a very short period of time, with a 50% loss in flow rate observed in about 35 minutes of continuous operation, while the same base fuel containing the detergent showed far less clogging over an extended period of time.
[0096] While the invention has been described in detail with
reference to preferred embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention.





We Claim:
1. An apparatus for producing power from a source of liquid fuel, characterized in that
the apparatus comprises :
(a) at least one capillary flow passage (12), said at least one capillary flow passage (12) having an inlet end (14) and an outlet end (16), said inlet end (14) in fluid communication with the source of liquid fuel;
(b) a heat source (20) arranged along said at least one capillary flow passage (12), said heat source (20) operable to heat the liquid fuel in said at least one capillary flow passage (12) to a level sufficient to change at least a portion thereof from a liquid state to a vapor state and deliver a stream of substantially vaporized fuel from said outlet end 16 of said at least one capillary flow passage (12);
(c) a combustion chamber (34) for combusting the stream of substantially vaporized fuel and air, said combustion chamber (34) in communication with said outlet end (16) of said at least one capillary flow passage (12); and
(d) a conversion device operable to convert heat released by combustion in said combustion chamber into mechanical and electrical power, said conversion device (30) comprising a Stirling engine with electrical generator (32), wherein said conversion device (30) outputs up to 5000 watts of electrical power;
(e) means for cleaning deposits formed during operation of the apparatus .

2. The apparatus as claimed in claim 1, wherein said heat source (20) comprises a resistance-heating element.
3. The apparatus as claimed in claim 1 or 2, comprising a fluid control valve (18) which controls the flow of liquid fuel from the liquid fuel source.
4. The apparatus as claimed in any proceeding claim, wherein said at least one capillary flow passage (12) comprises at least one capillary tube.
5. The apparatus as claimed in any proceeding claim, wherein said heat source (20) comprises a section of said capillary tube heated by passing an electrical current there through.
6. The apparatus as claimed in claim 1, wherein said means for cleaning deposits being
means for oxidizing the deposits or means for abrading deposits or means for in-situ cleaning of deposits using solvent.
7. The apparatus as claimed in claim 1 and 6, wherein said means for cleaning deposits by
oxidizing the deposits comprises a fluid control valve (18) for controlling the flow of liquid fuel from the liquid fuel source, said heat source (20) and an oxidizer control valve (26) for placing said at least one capillary flow passage (12 )in fluid communication with an oxidizer, said heat source (20) also being operable to heat the oxidizer in said at least one capillary flow passage (12) to a level sufficient to oxidize deposits formed during the heating of the liquid fuel, wherein said oxidizer control valve 26 for placing said at least one capillary flow passage (12) in fluid communication with an oxidizer is operable to alternate between the introduction of liquid fuel and the introduction of oxidizer into said capillary flow passage (12) and enables in-situ cleaning of said capillary flow passage (12) when the oxidizer is introduced into said at least one capillary flow passage (12).
8 The apparatus as claimed in claim 7, wherein said at least one capillary flow passage (12) comprises a plurality of capillary flow passages (12), each of said capillary flow

passages (12) being in fluid communication with a supply of fuel and a supply of oxidizing gas.
9. The apparatus as claimed in claim 7 or 8, wherein the oxidizer comprises air, exhaust gas, steam and mixtures thereof.
The apparatus as claimed in claim 1 and 6, wherein said means for abrading deposits comprises an axially movable rod (232) positioned so as to be in axial alignment with said at least one capillary flow passage (12).
The apparatus as claimed in claim 10, wherein said means for abrading deposits comprises cleaning brushes disposed along said axially moveable rod (232).
The apparatus as claimed in claim 1 and 6, wherein said means for in-situ cleaning of deposits comprises a fluid control valve (18) for controlling the flow of liquid fuel from the liquid fuel source and a solvent control valve (26) for placing said at least one capillary flow passage (12) in fluid communication with a solvent, said solvent control valve (26) disposed at one end of said at least one capillary flow passage (12), and wherein said solvent control valve (26) for placing said at least one capillary flow passage (12) in fluid communication with a solvent is operable to alternate between the introduction of liquid fuel and the introduction of solvent into said capillary flow passage (12) and enables in-situ cleaning of said capillary flow passage (12) when the solvent is introduced into said at least one capillary flow passage (12).
The apparatus as claimed in claim 6 and 12, wherein said means for cleaning deposits comprises a fluid control valve (18) for controlling the flow of liquid fuel from the liquid fuel source, said fluid control valve (18) operable for placing said at least one capillary flow passage in fluid communication with a solvent, enabling in-situ cleaning of said capillary flow passage (12) when the solvent is introduced into said at least one capillary flow passage (12).
The apparatus as claimed in claim 13, wherein the solvent comprises liquid fuel from the liquid fuel source and wherein the heat source (20) is phased-out during cleaning of said capillary flow passage.
A method of producing power by the apparatus as claimed in claim 1, the method comprising:
a. supplying liquid fuel to at least one capillary flow passage (12);
b. causing a stream of substantially vaporized fuel to pass through an outlet (16) of
the at least one capillary flow passage (12) by heating the liquid fuel in the at least
one capillary flow passage (12);
c. combusting the vaporized fuel in a combustion chamber (34); and
d. converting heat produced by combustion of the vaporized fuel in the combustion
chamber (34) into mechanical and electrical power using a conversion device (30)
comprising a Stirling engine with electrical generator (33) capable of outputing up
to 5000 watts of electrical power.
The method as claimed in claim 15, wherein the at least one capillary flow passage (12) comprises at least one capillary tube and the heat source (20) comprises a resistance heating element or section of the capillary tube heated by passing an electrical current

therethrough, the method comprising flowing the liquid fuel through the capillary tube and vaporizing the liquid fuel by heating the tube.
17. An apparatus for producing power from a source of liquid fuel substantially as herein described with reference to the foregoing description and the accompanying drawings.
18. A method of generating power substantially as herein described with reference to the foregoing description and the accompanying drawings.

Documents:

2786-DELNP-2004-Abstract-(06-02-2009).pdf

2786-delnp-2004-abstract.pdf

2786-delnp-2004-assignments.pdf

2786-DELNP-2004-Claims-(06-02-2009).pdf

2786-DELNP-2004-Claims-(18-02-2009).pdf

2786-delnp-2004-claims.pdf

2786-DELNP-2004-Correspondence-Others-(06-02-2009).pdf

2786-DELNP-2004-Correspondence-Others-(10-02-2009).pdf

2786-DELNP-2004-Correspondence-Others-(18-02-2009).pdf

2786-DELNP-2004-Correspondence-Others-(21-04-2008).pdf

2786-DELNP-2004-Correspondence-Others-(28-01-2009).pdf

2786-DELNP-2004-Correspondence-Others-(29-01-2009).pdf

2786-delnp-2004-correspondence-others.pdf

2786-delnp-2004-description (complete).pdf

2786-DELNP-2004-Drawings-(29-01-2009).pdf

2786-delnp-2004-drawings.pdf

2786-DELNP-2004-Form-1-(06-02-2009).pdf

2786-delnp-2004-form-1.pdf

2786-delnp-2004-form-13.pdf

2786-delnp-2004-form-18.pdf

2786-DELNP-2004-Form-2-(06-02-2009).pdf

2786-delnp-2004-form-2.pdf

2786-DELNP-2004-Form-3-(21-04-2008).pdf

2786-DELNP-2004-Form-3-(28-01-2009).pdf

2786-delnp-2004-form-3.pdf

2786-delnp-2004-form-5.pdf

2786-delnp-2004-form-6-(10-02-2009).pdf

2786-DELNP-2004-GPA-(06-02-2009).pdf

2786-DELNP-2004-GPA-(10-02-2009).pdf

2786-delnp-2004-pct-101.pdf

2786-delnp-2004-pct-210.pdf

2786-delnp-2004-pct-304.pdf

2786-delnp-2004-pct-409.pdf

2786-delnp-2004-pct-416.pdf

2786-DELNP-2004-Petition-137-(18-02-2009).pdf


Patent Number 232980
Indian Patent Application Number 2786/DELNP/2004
PG Journal Number 13/2009
Publication Date 27-Mar-2009
Grant Date 24-Mar-2009
Date of Filing 20-Sep-2004
Name of Patentee Phillip Morris USA Inc.
Applicant Address 615 MAURY ST. RICHMOD VA 23230-1723, UNITED STATES OF AMERICA.
Inventors:
# Inventor's Name Inventor's Address
1 PELLIZZARI, ROBERTO, O. 95 RADDIN ROAD, GROTON, MA 01450, USA.
PCT International Classification Number F23D 11/44
PCT International Application Number PCT/US03/09220
PCT International Filing date 2003-03-24
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/367,131 2002-03-22 U.S.A.
2 10/143,463 2002-05-10 U.S.A.