U.S. patent application number 12/068547 was filed with the patent office on 2008-10-02 for plasma actuated electronic catalytic converter.
Invention is credited to Michael E. Jayne, Jeffrey J. Karl.
Application Number | 20080241004 12/068547 |
Document ID | / |
Family ID | 39794712 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080241004 |
Kind Code |
A1 |
Jayne; Michael E. ; et
al. |
October 2, 2008 |
Plasma actuated electronic catalytic converter
Abstract
An apparatus and method for the breakdown of exhaust gas
pollutant molecules into their constituent atoms and then
re-assembling those atoms into low energy state non-toxic molecules
that are found in the atmosphere naturally is disclosed. A plasma
actuated electronic catalytic converter includes an exhaust gas
inlet, a first oxidization reaction chamber, a second reduction
reaction chamber, an exhaust gas outlet, and an electronics power
source. A first reaction chamber includes a plasma discharge
electrode and semi-spherical screen that are negatively biased by a
direct current source followed by a mixing screen and an anode
screen. A second reaction chamber includes a plasma discharge
electrode and semi-spherical screen that are positively biased by a
direct current source followed by a mixing screen, if needed, a
fresh air inlet, and a screen or screens that are negatively biased
so as to gradually return electrons to the exhaust gasses.
Inventors: |
Jayne; Michael E.; (Amherst,
MA) ; Karl; Jeffrey J.; (Williamsburg, MA) |
Correspondence
Address: |
SMITH PATENT OFFICE
1901 PENNSYLVANIA AVENUE N W, SUITE 901
WASHINGTON
DC
20006
US
|
Family ID: |
39794712 |
Appl. No.: |
12/068547 |
Filed: |
February 7, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60901306 |
Feb 15, 2007 |
|
|
|
Current U.S.
Class: |
422/173 |
Current CPC
Class: |
F01N 13/0093 20140601;
F01N 3/0892 20130101; F01N 2240/28 20130101 |
Class at
Publication: |
422/173 |
International
Class: |
F01N 3/10 20060101
F01N003/10 |
Claims
1. A plasma oxidization device comprising: an electrically
insulated outer casing with a gas flow inlet and a gas flow outlet;
a plasma discharge anode device disposed within the outer casing,
wherein the plasma discharge anode device includes a first plasma
discharge electrode and a second plasma discharge electrode,
wherein at least one of the first and second plasma discharge
electrodes can donate electrons; a gas mixing and charge
distribution mesh being electrically isolated from the outer
casing; an electron retrieval cathode mesh; a plasma generation
circuit connected to the-first and second plasma discharge
electrodes; and a direct current power source being operatively
connected to the electron retrieval cathode mesh and at least one
of the plasma discharge electrodes.
2. A plasma oxidation device according to claim 1, wherein a
negative output of the direct current power source is connected to
at least one of the plasma discharge electrodes and and a positive
output of the direct current power source is connected to the
electron retrieval cathode mesh.
3. A plasma reduction device comprising: an electrically insulated
outer casing with a gas flow inlet and a gas flow outlet; a plasma
discharge cathode device disposed within the outer casing, wherein
the plasma discharge cathode device includes a first plasma
discharge electrode and a second plasma discharge electrode,
wherein at least one of the first and second plasma discharge
electrodes can remove electrons for a gas; a gas mixing and charge
distribution mesh electrically isolated from the outer casing; a
plurality of electron return anode meshes; a plasma generation
circuit connected to the first and second plasma discharge
electrodes; and a direct current power source being operatively
connected to at least one of the electron return anode meshes and
at least one of the plasma discharge electrodes.
4. A plasma reduction device according to claim 1, wherein a
negative output of the direct current power source is connected to
the plurality of electron return anode meshes and a positive output
of the direct current power source is connected to at least one of
the plasma discharge electrodes.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a nonprovisional application of U.S.
Provisional Patent Application No. 60/901,306 filed on Feb. 15,
2007, currently pending. The disclosure of U.S. Provisional Patent
Application No. 60/901,306 is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method and apparatus for
improving exhaust after-treatment devices for use by diesel and
gasoline powered vehicles, generators, heavy equipment, industrial
power sources, fuel burners and other sources of airborne
pollutants from a wide variety of air pollution sources.
Specifically, the invention includes a plasma electronic catalyst
assisted molecular reformation of the elements within the exhaust
gases into their least toxic and lowest energy molecular states,
specifically, N.sub.2, CO.sub.2, and H.sub.2O, all of which occur
naturally within the atmosphere.
[0004] 2. Description of the Related Art
[0005] The plethora of exhaust after-treatment systems devoted to
reduction of pollution of the air are simply too numerous to
specifically reference individually. In the specific case of diesel
vehicles there is no system that, at present, is in widespread use
that treats the exhaust in a manner that is sufficiently efficient
or effective for it to be commercially viable and accepted at this
time. The reason for this is that to date no practical solution has
been found for the following issues: [0006] 1. High soot
(hydrocarbon particulate) output during engine warm-up that leads
to clogging of conventional metallic catalyst type catalytic
converters; [0007] 2. Very high NOx output due to the nature of
compression ignition used by diesel engines; and [0008] 3. The
sensitivity of the diesel engine to any exhaust restriction leading
to increased exhaust back-pressure which seriously degrades
performance.
[0009] A number of systems are under development, other than the
present invention, attempt to solve this problem but none of them
deal with the pollutant output of a diesel engine with a simple
elegant integrated solution that does not involve bulky and
complicated equipment, significantly degrade performance, and/or
increase fuel usage.
[0010] The plasma based emissions control technology now getting
the most developmental attention for diesel engines, is all based
on various non-thermal plasma or more simply corona discharge
plasma systems (or to a lesser extent fuel reformers which will be
discussed later). These systems have shown enough promise to
continue to attract research funding, but they have yet to reach
commercial viability. The reasons for this system's difficulty in
development are: [0011] 1. limitations in handling high amounts of
hydrocarbon particulates; [0012] 2. susceptibility to vibration of
the material used to provide a surface area for the corona
discharge; and [0013] 3. the bulk of the apparatus necessary to
create enough surface area to treat typical exhaust flow rates.
Although this technology has shown some promise in the laboratory,
the above mentioned problems have yet to be given cost effective
and market acceptable solutions.
[0014] The other plasma based exhaust treatment technology getting
research attention is one that uses the plasma with a conventional
filter and/or catalytic converter. A plasma fuel reformer is used
to create a reaction between a hydrocarbon of some sort (usually
fuel but in a couple of cases alcohol) and either air or exhaust
gas to create an intermediate compound (urea and aldehyde are both
mentioned in the prior art) that is then combined with the exhaust
gases before they enter either a filter trap or a metallic catalyst
type catalytic converter. These systems have been under development
for a number of years without reaching the market for the following
reasons: [0015] 1. they require either extra fuel or a totally
separate tank of its own special fuel to operate; [0016] 2. the
accompanying plumbing and apparatus is complex and expensive; and
[0017] 3. in many cases there is a filter trap that accumulates
solid waste that must be disposed of on a regular basis, which is
probably subject to EPA regulations.
[0018] New development activity for technologies of this type has
been declining lately probably due to the above stated issues. For
these reasons, the need for the present invention is greater now
than ever.
[0019] Automotive catalytic converters of the type mandated by
federal law for every car sold in America are a great success story
in terms of how much they have cleaned up the air we breathe.
Despite this, these catalytic converters have several serious
limitations. Conventional catalytic converters cannot be used to
treat the exhaust of diesel engines for oxides of nitrogen
(NO.sub.x) because of the presence of oxygen in the exhaust.
[0020] For a conventional catalytic converter to break down oxides
of nitrogen (NO.sub.x) in automotive exhaust, the engine is
deliberately de-tuned to run rich and produce carbon monoxide (CO),
normally considered a pollutant. However, in the presence of a
metallic catalyst at operating temperature, the carbon monoxide
(CO) completes its combustion by removing the additional oxygen
atom each molecule needs from the oxides of nitrogen (NO.sub.x) in
the automotive exhaust. Diesel engines on the other hand are
designed to be "over-scavenged" to insure complete removal of
exhaust gases at the end of each exhaust cycle. This results
inevitably in the presence of free oxygen in the exhaust. With free
oxygen available, the carbon monoxide (CO) completes its combustion
by using the free oxygen instead of reacting with the oxides of
nitrogen (NO.sub.x) thus defeating one of the primary purposes of
the conventional catalytic converter.
[0021] An additional limitation of the conventional catalytic
converter is the presence of the "Hydrocarbon Bubble". The
phenomenon that the E.P.A. refers to as the "Hydrocarbon Bubble" is
the pollution emitted by a modern gasoline fueled automobile
equipped with a conventional catalytic converter during its first
ten to twenty minutes of operation. Until the catalytic converter
reaches its approximate operating temperature at least 685.degree.
F., it does not function. Unfortunately, this also happens to be at
the same time that a gasoline fueled spark ignited engine is
getting an enriched fuel-air mixture during its warm-up period. The
resultant high output of pollution that occurs during engine
warm-up is referred to within the industry as the "Hydrocarbon
Bubble" and constitutes between 80 to 90% of the total air
pollution that the average automobile engine will make in a day.
Ironically this usually occurs within the first 10% of its
operation for each use.
[0022] Another problem associated with the conventional catalytic
converter is its susceptibility to a reduction in efficacy due to
fuel contamination. Substances such as lead or sulfur in the fuel
"poison" the rare earth metals used in the catalyst material
rendering them useless. These contaminant elements pass through the
combustion process without having their metallic catalyst
contaminant qualities affected. The only way to avoid this problem
is to avoid the dependence on metallic catalysts.
[0023] The effectiveness of the metallic catalyst in a conventional
catalytic converter is limited by its surface area. This problem is
obviated by the use of a plasma actuated electronic catalyst
instead of depending on a metallic catalyst. Since metallic
catalysts produce their effect of promoting a chemical reaction by
making electrons available for a chemical reaction without
otherwise directly participating in the reaction, use of a plasma
actuated electronic catalyst completely avoids the surface area
issue. If a stronger catalytic effect is needed the output level of
the direct current power supply for the present invention can be
increased to make a greater number of electrons available. This
power level output could be adjusted in response to signals from an
engine management computer or from sensors that respond to
pollutant levels in the exhaust to be treated, the presence of
pollutants in the treated exhaust, or by a variety of other sensor
feedback systems.
[0024] This same apparatus and method can also be applied to
industrial gaseous exhaust systems used by a wide variety of
processes and is not limited to just combustion occurring within
internal combustion engines.
[0025] The prior art for catalytic converters does not disclose any
apparatuses that electronically disassemble the pollutant molecules
within the exhaust gases into their constituent atoms. Nor does it
disclose any apparatuses that then electronically re-assemble these
same atoms from the exhaust gas pollutants into innocuous non-toxic
molecules normally found in the atmosphere.
SUMMARY OF THE INVENTION
[0026] As best understood, the present invention operates by having
the exhaust gas stream flow through into a reaction chamber by
passing through a plasma discharge device that either adds or
subtracts electrons depending upon the type of pollutants to be
treated. After this, the electrical charge is evenly distributed
and the gases are mixed to promote the desired reaction that either
oxidizes or reduces the pollutants as determined by whether
electrons were either added or subtracted. After the reaction has
taken place and the right conditions are achieved, then the
electrical charge in the gases caused by the electrons earlier
being added or subtracted are then returned to a balanced
condition. Once the exhaust gases reach an electrically neutral
charge, the treatment of gases for that set of pollutants meant to
be treated by that specific reaction, be it oxidization or
reduction, is complete.
[0027] More specifically, if both types of reaction chambers are
used together, the most practical arrangement is two reaction
chambers with the first chamber being a plasma oxidization reaction
chamber, and the second chamber being a plasma reduction reaction
chamber. The first chamber, a plasma oxidization reaction chamber
treats hydrocarbons (C.sub.xH.sub.x), partially combusted
hydrocarbons to include hydrocarbon particulates
(C.sub.xH.sub.xO.sub.x), carbon monoxide (CO) and especially the
carcinogenic aromatic nitrogenated hydrocarbon particulates
(C.sub.xH.sub.xN.sub.xO.sub.x). The second chamber, a plasma
reduction reaction chamber, treats ozone (O.sub.3), and oxides of
nitrogen (NO.sub.x).
[0028] The plasma oxidization reaction chamber uses a plasma
discharge anode device to introduce free electrons into the gas
stream. These free electrons act as an electronic catalyst to
promote the breakdown and oxidization of the hydrocarbon based
pollutants. This action is similar to and an improvement upon
metallic catalysts, which work by making electrons available to the
chemical reaction that they are assisting. In addition to the
electronic catalytic action circumventing the surface area problem
of metallic catalysts, there is not an opportunity for soot
(hydrocarbon particulates) to build up and clog the apparatus
before it is oxidized.
[0029] The plasma reduction reaction chamber first uses a plasma
discharge cathode device to strip electrons from highly polar, high
energy state molecules such as O.sub.3 and NO.sub.x. This stripping
of electrons from these oxides causes them to break down into their
individual constituent atoms in a positively ionized state. Then
the plasma reduction reaction chamber has the gases containing
these ionized atoms cooled down to the appropriate lower
temperature. With the temperature of the gases reduced, and by
having the final series of anodes gradually return the electrons to
the atoms, there would not be enough energy available to
re-constitute them into ozone (O.sub.3) and oxides of nitrogen
(NO.sub.x). Instead, when the electrons are returned to the atoms
from the second set of pollutants, they will come together in their
lowest energy state to reform the molecules of N.sub.2 and O.sub.2.
Molecular nitrogen (N.sub.2) and molecular oxygen (O.sub.2) are
innocuous compounds normally found in the atmosphere. These last
set of anodes also balance out into neutrality the electrical
charge of the exhaust gases.
[0030] By doing all of this, the present invention can take in
complex nitrogenated aromatic hydrocarbon particulates (a
carcinogen found in diesel engine exhaust that is responsible for
several hundred thousand cancer cases in the USA each year), NOx,
CO, and other pollutants, break them down and then reform them into
compounds that normally occur in the air we breath. The benefits of
the present invention are complimentary with and in addition to
those achieved by all other methods currently in use to reduce the
pollutant content of gaseous exhaust outputs.
[0031] It is accordingly an object of the present invention to
provide an apparatus and method for assuring the immediate and
complete breakdown of the pollutants in exhaust gases and their
subsequent reformation into innocuous gases that are normally found
in the atmosphere.
[0032] It is a further object of the present invention to make
possible the practical and economically viable retrofitting of
existing vehicles, engines, furnaces, and other sources of air
pollution with an apparatus and method that provides for the
complete treatment of their exhaust gases.
[0033] Another object of the present invention when applied to
vehicles, engines or other noisy industrial processes is to provide
for the combined functions of noise pollution control as well as
air pollution control in the same apparatus.
[0034] The outer housing of the main body of the Plasma Actuated
Electronic Catalytic Converter comprises of an electrically
insulated outer casing that contains the reaction chamber(s). In
the most complete and effective version of the present invention,
the electrically insulated outer casing encloses two reaction
chambers. The first one is a plasma oxidization reaction chamber.
The exhaust gases are subjected to a plasma discharge as soon as
they enter the plasma oxidization reaction chamber. This plasma
discharge occurs between a centrally located plasma discharge
electrode and a relatively open mesh plasma discharge screen that
the exhaust gases flow past and then through. To create this plasma
discharge, both the centrally located plasma discharge electrode
and the relatively open mesh plasma discharge screen are provided
with a multi-frequency high voltage current by a plasma generation
circuit.
[0035] In order to produce the electronic catalytic action,
electrons must be added to the exhaust gases as they pass through
the plasma discharge. This is accomplished by having the relatively
open mesh plasma discharge screen also act as an anode to provide
the extra free electrons necessary for oxidization catalysis. For
this to happen, the relatively open mesh plasma discharge screen is
connected to the negative voltage output of a direct current power
source as well as to one of the multi-frequency high voltage
outputs of the plasma generation circuit.
[0036] Collectively, the structure that subjects the exhaust gases
to a plasma discharge and also adds the extra free electrons needed
for the electronic catalytic oxidization to take place is referred
to as a plasma discharge anode device. This comprises of the plasma
generation circuit connected to both the centrally located plasma
discharge electrode and the relatively open mesh plasma discharge
screen with the relatively open mesh plasma discharge screen also
connected to the negative voltage output of the direct current
power source. This electrical connection of the relatively open
mesh plasma discharge screen to the negative voltage output of the
direct current power source is the source of the extra free
electrons needed for the electronic catalytic oxidization action to
take place.
[0037] In order to prevent particulate matter (soot) from causing
clogging up of the plasma discharge anode device, there is a
constant radius from the tip of the centrally located plasma
discharge electrode (or alternative structure) to every point on
the surface of the relatively open mesh plasma discharge screen
which the gases flow through. By being set up with a constant
radius, any particulate matter (soot) that should build up on the
relatively open mesh plasma discharge screen would present a
shorter distance for the plasma discharge to cross from the
centrally located plasma discharge electrode to the part of the
screen with the soot. As a result of this, the focus of the
discharge would shift to that location on the relatively open mesh
plasma discharge screen having the effect of literally blasting
that soot into atoms. To enable this screen to handle the process
and environment that it is subjected to, it would preferably be
made of heavy gage high temperature stainless steel or some other
appropriate alternative material. It is also within the spirit and
intent of the present invention for the plasma discharge anode
device to be comprised of alternative structures for the individual
internal components that accomplish the same function.
[0038] After the exhaust gases pass through the plasma discharge
anode device, they are thoroughly mixed and have the extra free
electrons evenly distributed throughout by an electrically isolated
gas mixing and charge distribution spiral screen. It is here that
the majority of the electronic catalytic reaction takes place.
While passing through the electrically isolated gas mixing and
charge distribution spiral screen, the extra free electrons will
have their electronic catalytic effect on the pollutants in the
exhaust by aiding the oxidization process, causing it to take place
rapidly and completely. Anything that has not been yet been
oxidized will be oxidized by the addition of electrons (oxidization
is accomplished through the donation of electrons), thus changing
the hydrocarbons (CH.sub.x), partially combusted hydrocarbons
(C.sub.xH.sub.xO.sub.x), carbon monoxide (CO), and hydrocarbon
particulates from the exhaust gases into carbon dioxide (CO.sub.2)
and water (H.sub.2O) however the oxides of nitrogen (NO.sub.x) will
remain unaffected. In addition to free electrons, the other thing
needed for this electronic catalytic oxidization to take place is
available oxygen from extra air.
[0039] When used for treating diesel engine exhaust the extra air
needed for the complete treatment of hydrocarbons is already
available because diesel engines are "over-scavenged" and run with
a lean fuel-to-air ratio. This over-scavenging usually occurs at
the end of the exhaust stroke when both the intake and exhaust
valves (or ports) are kept open and extra air is sent completely
through the combustion chamber into the exhaust manifold in order
to insure that as much of the exhaust as possible has been removed
(scavenged) from it before the next intake of fresh air into the
combustion chamber. Also, diesel engines are always set up so that
there is more air than necessary for a stoichiometric mixture of
fuel and air in order to insure that the most complete combustion
possible can occur under the circumstances.
[0040] When used for treating gasoline powered engine exhaust the
additional air needed for the complete treatment of hydrocarbons is
already available from the air pump or other device already in
place for use with the conventional catalytic converter that the
present invention would be replacing.
[0041] Actually an automotive gasoline engine equipped with the
present invention could have its brake specific fuel consumption
(BSFC: the ratio of horsepower over time per unit of fuel consumed)
significantly improved while still meeting environmental
regulations for oxides of nitrogen (NO.sub.x) content in the
exhaust. This is possible because for a conventional catalytic
converter to operate, the spark ignited engine must be deliberately
de-tuned in order to insure the production of carbon monoxide (CO)
in the exhaust. Also the compression ratio of the engine must be
limited in order to limit the production of oxides of nitrogen
(NO.sub.x) in the automotive exhaust so that it does not overwhelm
the production of carbon monoxide (CO) produced by de-tuning. This
is because the carbon monoxide (CO) is used in the conventional
catalytic converter to react with the oxides of nitrogen (NO.sub.x)
to produce molecular nitrogen (N.sub.2) and carbon dioxide
(CO.sub.2) in the exhaust. In a vehicle equipped with the present
invention the engine can be tuned for maximum efficiency instead of
being de-tuned. Also since the present invention is more effective
in treating the oxides of nitrogen (NO.sub.x) to begin with, it is
possible to raise the compression ratio of the spark ignited engine
as well which would further increase the brake specific fuel
consumption (BSFC).
[0042] When used for other applications such as industrial process
exhaust treatment, if the gases are oxygen free it may be necessary
to provide for additional air to be introduced to the exhaust
before it enters the present invention.
[0043] Electronic catalysis is an improvement over the action of
metallic catalysts that also work by making electrons available to
the chemical reaction in order to facilitate the process they are
applied to. The three primary advantages of using an electronic
catalyst over a metallic catalyst are: [0044] 1. Metallic catalysts
do not become active until they reach their operating temperature,
before that they do not contribute anything to the reaction unlike
an electronic catalyst that operates once the circuit is turned on;
[0045] 2. The effectiveness of an conventional catalyst is limited
by its surface area, whereas with an electronic catalyst the extent
of electrons available to assist the chemical reaction can be
determined by the amount of current that the designer wishes to use
for a given application, or by a sensor feedback system that
responds in real time to the operating conditions encountered; and
[0046] 3. A ceramic substrate that is long, thin and easily clogged
with soot, is not needed at all with an electronic catalyst. With
these advantages, electronic catalysis as a process can accomplish
many things that have defied treatment by conventional catalytic
converters.
[0047] In addition to its other functions dealing with electronic
catalysis, the electrically isolated gas mixing and charge
distribution spiral screen also contributes to noise control by
helping to break up standing waves of acoustic energy. This last
feature is especially important for the diesel over-the-road truck
market with the functions of exhaust treatment and noise abatement
provided for in one retrofitted device. It will only require the
space already allocated for the muffler already in place on diesel
powered buses and trucks.
[0048] Although a spiral screen is specified throughout this
section, it is to be understood that it is within the spirit and
intent of the invention to utilize alternative screen
configurations, or other structures that accomplish the same
function.
[0049] In the simpler variation of the plasma oxidization reaction
chamber, meant to handle lesser loads of hydrocarbon based
pollutants, after enough of a distance to insure electrical
isolation from the electrically isolated gas mixing and charge
distribution spiral screen, the exhaust gases pass through an
electron retrieval cathode conical screen. This is connected to the
positive voltage output of the direct current power source for
recovering the extra free electrons used in the plasma catalytic
oxidization reaction. By removing these extra free electrons used
for the electronic catalytic reaction it also balances out to
neutrality the overall electrical charge of the exhaust gases
leaving the plasma oxidization reaction chamber. In the simpler
variation of the plasma oxidization reaction chamber, it has the
exhaust gases completely exit the apparatus at this point. If the
exhaust gases also contain pollutant oxides, such as oxides of
nitrogen (NO.sub.x) then it enters the next section, a plasma
reduction reaction chamber. If however, this is not the case, this
is not necessary and the process is complete.
[0050] However for the version of the plasma oxidization reaction
chamber required to handle greater concentrations of hydrocarbon
pollutants, the next thing encountered by the exhaust gases after
the electrically isolated gas mixing and charge distribution spiral
screen is an electron retrieval cathode spiral screen. This
achieves the same functions of electron retrieval and electrical
neutrality of the exhaust gases as the electron retrieval cathode
conical screen used in the previously discussed variation of the
plasma oxidization reaction chamber. The electron retrieval cathode
spiral screen is also connected to the positive voltage output of
the direct current power source but since it has a number of turns
and much more surface area, it contributes to two other functions
as well: [0051] 1. It helps to cool down the exhaust gases in order
to limit the re-formation of NO.sub.x; and [0052] 2. It also
further contributes to noise reduction. However, at this point in
the treatment process, although all of the hydrocarbon based
pollutants have been oxidized into carbon dioxide (CO.sub.2) and
water (H.sub.2O), the oxides of nitrogen (NO.sub.x) remain
unaffected.
[0053] In order to avoid wasting energy from the plasma oxidization
reaction chamber during its operation, a hydrocarbon pollutant
level sensor can used to monitor the amount of hydrocarbons
contained by the incoming exhaust gases. This information will be
used to determine more precisely the amount of current needed to
thoroughly oxidize the hydrocarbons in the incoming exhaust gases.
By providing a control signal to the direct current power source,
so that it produces just the appropriate amount of free electrons
necessary to oxidize the hydrocarbons present, power waste can be
avoided and component life can be extended. This is especially
important when the present invention is applied to treating engine
exhaust. When the engine first starts up, during its warm-up period
it produces much more hydrocarbon based pollutants than it does
after it has run long enough to warm-up. During this time, more
power would be needed to effectively treat the exhaust gases. After
warm-up, the hydrocarbon pollutant level sensor would detect the
drop in incoming hydrocarbons and the power output from the direct
current power source could be reduced accordingly.
[0054] The plasma oxidization reaction chamber can exist as a stand
alone device for the treatment of hydrocarbon based pollutants by
themselves. If there are not any oxides of nitrogen in need of
treatment in the exhaust gases, then the process is complete with
just the plasma oxidization reaction chamber by itself as a
stand-alone device.
[0055] After leaving the plasma oxidization reaction chamber the
exhaust gases will enter the plasma reduction reaction chamber
which is the second chamber of the device meant to treat both types
of pollutants found in diesel engine exhaust for an example.
Although there are alternative second reaction chamber
configurations they all have in common a plasma discharge cathode
device as the first thing encountered by the exhaust gases as they
enter the chamber.
[0056] The plasma discharge cathode device consists of exactly the
same components as the plasma discharge anode device with the only
difference being the polarity of its connections to the direct
current power source being used for the plasma reduction reaction
chamber. For the purpose of clarification, the plasma discharge
cathode device is comprised of the plasma generation circuit
connected to both the centrally located plasma discharge electrode
and the relatively open mesh plasma discharge screen with the
relatively open mesh plasma discharge screen also connected to the
positive output of the direct current power source for the plasma
reduction reaction chamber. There is a constant radius from the tip
of the centrally located plasma discharge electrode (or other
structure) to every point on the surface of the relatively open
mesh plasma discharge screen which the gases flow through. For this
screen to handle the process and environment that it is subjected
to, it would preferably be made of heavy gage high temperature
stainless steel or some other appropriate alternative material.
[0057] The function of the plasma reduction reaction chamber is the
removal of electrons from the various pollutant oxides,
specifically oxides of nitrogen (NO.sub.x), to break them down into
their individual component atoms. In the field of chemistry the
process of reversing oxidization through the removal of electrons
is referred to as reduction, hence the name of this portion of the
present invention: the plasma reduction reaction chamber. If the
exhaust gas flow is only being treated for pollutant oxides such as
oxides of nitrogen (NO.sub.x) then the plasma reduction reaction
chamber can be used as a stand-alone device.
[0058] For the treatment of pollutants in the exhaust gases the
electrons removed will tend to come off of those molecules that are
highly polar in nature and in a high energy state to begin with
such as ozone (O.sub.3) and oxides of nitrogen (NO.sub.x) leaving
alone the more stable molecules such as carbon dioxide (CO.sub.2)
and water (H.sub.2O). To avoid breaking down non-pollutant
molecules and wasting power from the direct current power source,
the extent of electron stripping can be controlled by an oxides of
nitrogen pollution level sensor. This sensor is used to detect the
presence of oxides of nitrogen (NO.sub.x) in the exhaust as it
leaves the plasma reduction reaction chamber or to detect the level
of oxides of nitrogen (NO.sub.x) present in the incoming exhaust
gases if the plasma reduction reaction chamber is being used as a
stand alone device. This would provide feedback or input to control
power output from the direct current power source in order to
insure that only enough direct current is supplied to strip
electrons from just the high energy state pollutant oxides without
affecting the more stable non-pollutant compounds such as carbon
dioxide (CO.sub.2) and water (H.sub.2O).
[0059] The high energy state pollutant molecules have their shared
outer valence electrons removed causing them to break apart into
their constituent atoms leaving them in an ionized state. To insure
that the entire gas stream is treated after passing through the
plasma discharge cathode device they will then flow through the
electrically isolated gas mixing and charge distribution spiral
screen with the following three functions: [0060] 1. Mixing the
exhaust gases and evenly distributing the positive electrical
charge; [0061] 2. As a heat sink to reduce the temperature of the
exhaust gases in order to inhibit the re-formation of oxides of
nitrogen (NO.sub.x); and [0062] 3. To provide for additional noise
abatement.
[0063] An option within the present invention includes a cooler
fresh air inlet pipe that introduces cooler fresh air into the
exhaust gases approximate in the middle of the electrically
isolated gas mixing and charge distribution spiral screen to
further cool down the gases. This exhaust gas dilution and cooling
effect is very important to insure that oxides of nitrogen
(NO.sub.x) are not re-created when the electrons are returned. For
application to internal combustion engines, this option is most
easily applied if an air pump, turbo-charger, or super-charger is
already available as a source of air with the best practice being
to have the air pass through an intercooler to cool them down
before being introduced into the flow of exhaust gases.
[0064] After the exhaust gases containing ionized atomic nitrogen
and ionized atomic oxygen leave the electrically isolated gas
mixing and charge distribution spiral screen, they enter the
section where the electrons are gradually returned. The electron
return function is accomplished by a series of screens, each
individual one being either an electron return anode spiral screen,
an electron return anode conical screen, or an electron return
anode hemispherical screen. There is also the option of using a
resistive electron return anode spiral screen for a smoother
voltage gradient to do electron return compared to using a series
of electron return anode screens.
[0065] The key to avoiding the formation of higher energy pollutant
compounds such as oxides of nitrogen (NOx) and ozone (O.sub.3)
during the electron return phase is having each screen in the
series only getting a portion of the return voltage from the
relatively open mesh plasma discharge screen of the plasma
discharge cathode device. This is done by having each screen that
the exhaust gases pass through have progressively less resistance
between it and the negative terminal of the direct current power
source that has its positive terminal connected to the relatively
open mesh plasma discharge screen of the plasma discharge cathode
device. In order to insure complete electrical charge neutrality of
the exhaust gases exiting the plasma reduction reaction chamber,
the final electron return screen that the exhaust gases pass
through has no resistance between it and the negative terminal of
the direct current power source of the plasma reduction reaction
chamber.
[0066] It is may also possible to use a single anode screen if the
material that it is made of has sufficient resistance in the
material it is constructed from so that there will be a significant
voltage drop across the length of the screen. By having the
negative output of the direct current power source connected to the
end of the end of the screen closest to the exhaust gas exit of the
present invention, there will be a voltage gradient across its
length. This voltage gradient will result in a smoother gradient of
electron return compared to using a series of electron return anode
screens.
[0067] Since the exhaust gases have been cooled below the
temperature at which oxides of nitrogen (NOx) can form and the
outer valence electrons are being returned at a controlled and
gradual rate, not enough energy is available from the heat of the
exhaust gases and the energy released by electrons being returned
together for the formation of such compounds as oxides of nitrogen
(NOx) and ozone (O.sub.3). This ensures that the exhaust exiting
the device consists of compounds that already exist within the
atmosphere such as molecular nitrogen (N.sub.2), carbon dioxide
(CO.sub.2), molecular oxygen (O.sub.2), and water (H.sub.2O) which
present no threat to the public health.
[0068] With the integration of pollution and noise control in one
device it makes possible the equipping of all of the diesel engine
powered vehicles on the road today with the present invention.
Since there is so little change to the existing structure of the
vehicle, there is no excuse not to retro-fit everything on the road
to bring them into compliance with the 2009 diesel engine emission
regulations.
[0069] This is especially important since that there are several
hundred thousand cases each year of cancer in the United States
that have been directly linked to nitrogenated aromatic hydrocarbon
particulate emission from diesel trucks and buses. To have a
solution that because of its ease of installation can be
implemented across the board to include vehicles presently in use
is of incredible importance.
[0070] It is within the spirit and intent of the present invention
for either the plasma oxidization reaction chamber or the plasma
reduction reaction chamber to be used as an individual stand-alone
device or in any of a number of combinations with each other or
other apparatuses for the treatment of exhaust gases. Whether or
not one type of reaction chamber, the other, or both are used and
in what combination they are with each other or with other
pollution control devices used are dependent on what pollutants are
present in the exhaust being treated.
[0071] With the enormous personal heartbreak, societal costs,
diverted economic resources, and specifically governmental
expenditures in the form of Medi-Care and Medic-Aid costs that
threaten to bankrupt our healthcare system, there is enormous
pressure to get all of the diesel powered vehicles in the USA to
pollute much less. With the present invention, it is not necessary
to "grandfather" in older vehicles already on the road. The present
invention offers this capability with a minimum of change to the
existing design and structure of vehicles already in use at a
minimum of expense to the vehicle owner and/or operator.
[0072] The present invention also has the capacity to be up-scaled
to provide large scale treatment of industrial process exhaust as
well which provides a new and different tool for the control of air
pollution.
BRIEF DESCRIPTION OF THE DRAWINGS
[0073] The above and other objects and features of the present
invention will be clearly understood from the following description
with respect to the preferred embodiment thereof when considered in
conjunction with the accompanying drawings and diagrams, in
which:
[0074] FIG. 1 is a cross sectional side view of the entire exhaust
after treatment apparatus of the present invention installed in an
exhaust pipe.
[0075] FIG. 2A is a cross sectional side view of the plasma
oxidization reaction chamber with an electron retrieval conical
cathode screen.
[0076] FIG. 2B is a cross sectional side view of the plasma
oxidization reaction chamber including an exhaust gas cooling and
cathode screen.
[0077] FIG. 3 is a cross sectional side view of the plasma
reduction reaction chamber equipped with a set of the electron
return anode conical screens.
[0078] FIG. 4A is a cross sectional side view of the electron
return portion of the electron return anode spiral screen equipped
with a set of an electron return anode hemispherical screens.
[0079] FIG. 4B is a cross sectional side view of the electron
return portion of the electron return anode spiral screen equipped
with a set of the electron return anode spiral screens.
[0080] FIG. 4C is a cross sectional side view of the electron
return portion of the plasma reduction reaction chamber equipped
with the electron return anode spiral screen made of resistive
material.
[0081] FIG. 5 is a schematic of the plasma generation circuit in
its simplest form.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0082] The invention will now be described in further detail in
connection with illustrative preferred embodiments for improving
exhaust after-treatment of industrial processes, furnaces, and
internal combustion engines. Special attention will be paid to the
problems faced in the treatment of exhaust from diesel engines.
There will be presented several different variations of each
section of the device within the scope of the present
invention.
[0083] Referring to FIG. 1, the present invention is shown treating
an exhaust output from a diesel engine 101 which enters a plasma
oxidization reaction chamber 103 which is enclosed in an
electrically insulated outer casing 105. As the gases to be treated
flow in the first thing they encounter is a hydrocarbon pollutant
level sensor 107 just before they are subjected to the first phase
of the treatment process. This process is the ionization and the
addition of electrons to the exhaust gases by a plasma discharge
anode device 109 which consists of a centrally located plasma
discharge electrode 111 and a relatively open mesh plasma discharge
screen 113.
[0084] A plasma generation circuit 115 supplies the centrally
located plasma discharge electrode 111 and the relatively open mesh
plasma discharge screen 113 with the high voltage multi-frequency
electrical current produces a plasma discharge 99 (not shown in
FIG. 1) that ionizes the exhaust gases as they flow through the
plasma discharge anode device 109. By having the relatively open
mesh plasma discharge screen 113 have open mesh design and be at a
constant radius from the centrally located plasma discharge
electrode 111, the problem from hydrocarbon particulate (soot)
build-up causing clogging is avoided. This is because the open mesh
design does not significantly restrict flow in the first place and
more importantly, when any soot does deposit on the relatively open
mesh plasma discharge screen 113, it has a reduced distance between
it and the centrally located plasma discharge electrode 111. The
result of this reduced distance at the location of the soot
build-up is that the plasma discharge 99 (not shown in FIG. 1) will
shift its point of focus on the relatively open mesh plasma
discharge screen 113 to the soot literally blasting it into atoms
thus preventing any clogging from taking place.
[0085] The relatively open mesh plasma discharge screen 113 is also
connected to a negative output lead 117 of a high voltage direct
current power source 119 to provide the extra free electrons to the
exhaust gas being treated for the electronic catalytic effect to
take place. The high voltage direct current power source 119 is of
a type than be obtained "off-the-shelf" from a commercial power
supply manufacturer and is well known within the art to include
those models with the feature of having their output level
controlled by some kind of sensor input.
[0086] To avoid wasting power and extend the life of the system
components, the needed amount of extra electrons provided for the
electronic catalytic action from the high voltage direct current
power source 119 is controlled by the hydrocarbon pollutant level
sensor 107 which sends its signal through a sensor signal line 108.
This system is especially useful when the present invention is
applied to internal combustion engines used to power vehicles which
produce widely differing amounts of hydrocarbons depending on their
operating conditions. Specifically, when an engine is warming up,
it produces a very high amount of hydrocarbons and the high voltage
direct current power source 119 would have to produce much more
current in order to effectively treat the exhaust. Once the engine
is warmed up, the amount of hydrocarbons produced decreases
dramatically reducing the need for electronic catalytic action
which will be sensed by the hydrocarbon pollutant level sensor 107
with the power output of the high voltage direct current power
source 119 reduced accordingly.
[0087] Since the plasma discharge anode device 109 can not possibly
treat all of the exhaust gases exactly evenly or equally, and
because time with space in addition to the extra electrons are
needed for electronic catalysis to take place, the exhaust gases
need to be thoroughly mixed. To do this, after enough spacing to
insure electrical isolation between the two components the next
thing encountered by the exhaust gases is an electrically isolated
gas mixing and charge distribution spiral screen 121. It is to be
understood that it is within the spirit of the present invention to
employ alternative structures to a spiral screen to accomplish the
same function. It is in this part of the plasma oxidization
reaction chamber 103 that the hydrocarbon based pollutants are
oxidized completely.
[0088] The electrons used to achieve the catalytic action are
recovered by an electron retrieval cathode conical screen 123 after
enough spacing to insure electrical isolation between the two
components. This is connected to a positive output lead 125 of the
high voltage direct current power source 119 which in the process
of picking up the extra electrons also balances out into neutrality
the electrical charge of an exhaust flow free of hydrocarbon based
pollutants 126 leaving the plasma oxidization reaction chamber
103.
[0089] It is within the spirit and intention of the present
invention for any of a number of different cathode screen
configurations (or other structure to accomplish the same function)
to retrieve the extra free electrons added by the plasma discharge
anode device 109 inside the plasma oxidization reaction chamber
103.
[0090] The exhaust flow free of hydrocarbon based pollutants 126
now enter a plasma reduction reaction chamber 127 that treats the
non-hydrocarbon pollutants such as oxides of nitrogen (NO.sub.x).
The first thing that the exhaust gases encounter is a plasma
discharge cathode device 129 that just like the plasma discharge
anode device 109, it consists of another set of a centrally located
plasma discharge electrode 131 and a relatively open mesh plasma
discharge screen 133. Similarly, it too is connected to a plasma
generation circuit 135 but the difference is that the plasma
discharge cathode device 129 has the relatively open mesh plasma
discharge screen 133 connected to a positive output lead 137 of a
high voltage direct current power supply 139. The effect of this is
to strip electrons from the ionized gases passing through the
plasma discharge cathode device 129 resulting in a breakdown of
high energy state highly polar pollutant oxides such as oxides of
nitrogen (NO.sub.x).
[0091] To keep the electron stripping process selective, prevent
energy waste, and to increase the life of the parts, the amount of
power applied to the electron stripping process by the high voltage
direct current power supply 139 is controlled by an oxides of
nitrogen pollutant level sensor 141 which sends its signal through
a sensor signal line 142. This feedback loop will insure that just
enough power was supplied to the plasma reduction reaction chamber
127 by the high voltage direct current power supply 139 to break
down the oxides of nitrogen (NO.sub.x) in the exhaust without
squandering energy or the useful life of component breaking down
non-pollutants. Just like the high voltage direct current power
source 119 used for the plasma oxidization reaction chamber 103,
the high voltage direct current power supply 139 used for the
plasma discharge cathode device 129 is of a type than be obtained
"off-the-shelf" from a commercial power supply manufacturer and are
well known within the art. These can be purchased with the feature
of having their output level controlled by some kind of sensor
input.
[0092] Since the plasma discharge cathode device 129 can not
possibly treat all of the exhaust gases exactly evenly or equally,
and because the ionized atoms from the pollutant oxides must be
significantly cooled down before the electrons are returned to them
in order to avoid re-formation of oxides of nitrogen (NO.sub.x),
the next thing they go through is an electrically isolated gas
mixing and charge distribution spiral screen 143. Between the
relatively open mesh plasma discharge screen 133 and the
electrically isolated gas mixing and charge distribution spiral
screen 143 there is enough of an interval to insure electrical
isolation between the two components. It is to be understood that
it is within the spirit of the present invention to employ
alternative structures to a spiral screen to accomplish the same
function. If the electrically isolated gas mixing and charge
distribution spiral screen 143 is not sufficient to effectively
cool the ionized atoms from the pollutant oxides, it is within the
spirit of the invention to include the option of a cooler fresh air
inlet pipe 145. This will further cool the exhaust gases by
diluting them with cooler fresh air from an outside source (not
shown) such as a bleed-off from the turbo-charger, supercharger, or
air pump with the air cooled by an intercooler (not shown).
[0093] With the exhaust gases sufficiently cooled down the next
step is to re-assemble the atoms from the pollutant oxides into
non-toxic innocuous compounds. In order to avoid releasing too much
energy at one time in one place leading to oxides of nitrogen
(NO.sub.x) being created, electron return is done gradually by four
individual units of an electron return anode conical screen 147.
Each of the electron return anode conical screens 147 gets its
supply of electrons ultimately from the high voltage direct current
power supply 139 through the negative output lead 149 from the high
voltage direct current power supply 139. The rate of electron
return is controlled by changing the amount of resistance between
each of the electron return anode conical screens 147 and the high
voltage direct current power supply 139.
[0094] The electron return anode conical screen 147 closest to the
electrically isolated gas mixing and charge distribution spiral
screen 143 is connected to a high value current limiting resistor
151. The actual resistance for an operational unit being determined
by the specific conditions of the application but for purposes of
illustration in this description will be referred to as X ohms. The
high value current limiting resistor 151 is in turn connected to
the negative output lead 149 coming from the high voltage direct
current power supply 139. The electron return anode conical screen
147 that comes next is connected to a medium value current limiting
resistor 153 with a resistance of 2/3 X ohms which is in turn
connected to the negative output lead 149 coming from the high
voltage direct current power supply 139. The electron return anode
conical screen 147 that follows the previous two is connected to a
low value current limiting resistor 155 with a resistance of 1/3 X
ohms which is in turn connected to the negative output lead 149
coming from the direct current power supply 139. Finally, to insure
that all of the electrons are returned and that the electrical
charge of the gases leaving the present invention is neutral, the
electron return anode conical screen 147 that comes at the end of
the process is connected directly to the negative output lead 149
coming from the high voltage direct current power supply 139
without any resistor.
[0095] The operative concept employed in this section is the
gradual return of electrons. It is within the spirit and intention
of the invention to employ any of a number of screen designs, a
different number of screens than four, and/or any mixture of screen
designs to accomplish the function done by the four of the electron
return anode conical screens 147 mounted in the plasma reduction
reaction chamber 127 shown in FIG. 1.
[0096] The one last thing that the exhaust gases flow past before
they exit the present invention is an oxides of nitrogen pollutant
level sensor 141 used to control the power output level from the
high voltage direct current power supply 139 as described earlier.
At this point, all of the exhaust gases have been treated: the
hydrocarbon based pollutants have been subjected to electronic
catalysis and thoroughly oxidized into carbon dioxide (CO.sub.2)
and water (H.sub.2O) inside the plasma oxidization reaction chamber
103 and the pollutant oxidants have been molecularly disassembled
and then the atoms re-assembled into molecular oxygen (O.sub.2) and
molecular nitrogen (N.sub.2) by the plasma reduction reaction
chamber 127. Exiting the present invention is an output flow of
treated exhaust gases 157.
[0097] Referring to FIG. 2A, a cut-away close-up view of the plasma
oxidization reaction chamber 103 with the plasma discharge 99 shown
between the centrally located plasma discharge electrode 111 and
the relatively open mesh plasma discharge screen 113. Also shown is
an exhaust gas flow free of hydrocarbon based pollutants 126
exiting the plasma oxidization reaction chamber 103 and entering
the plasma reduction reaction chamber 127 (not shown). Other than
this, FIG. 2A is an exact duplicate of the plasma oxidization
reaction chamber 103 portion of the present invention that was
described in detail for FIG. 1.
[0098] FIG. 2B is a cut-away close-up view of the plasma
oxidization reaction chamber 103 shown with a component variation
in place designed to reduce the temperature of the exhaust gases
being treated. This function is done by having an electron
retrieval cathode spiral screen 159 perform the electron return
function with a much greater surface area than the electron
retrieval cathode conical screen 123 shown in FIG. 2A. The greater
surface area of the electron retrieval cathode spiral screen 159
will have the effect of reducing the temperature of the exhaust
gases being treated. Prior to this point in the process, the
temperature of the exhaust gases being treated has been raised by
the combustion of the hydrocarbons (C.sub.xH.sub.x), partially
combusted hydrocarbons (C.sub.xH.sub.xO.sub.x), carbon monoxide
(CO), and hydrocarbon particulates. At the point that the electrons
are returned, the temperature is further raised by the electrical
discharge between the ionized exhaust gases and the beginning of
the electron retrieval cathode spiral screen 159. However, as the
exhaust gases travel through the length of the electron retrieval
cathode spiral screen 159, it will absorb heat from the exhaust
gases passing through it. This is of great importance if the plasma
oxidization reaction chamber 103 is going to be used in conjunction
with the plasma reduction reaction chamber 127. The cooler the
exhaust gas flow free of hydrocarbon based pollutants 126 is
entering the plasma reduction reaction chamber 127, the easier it
is to avoid the re-formation of oxides of nitrogen (NO.sub.x) in
the following reduction process.
[0099] FIG. 3 shows the plasma reduction reaction chamber 127 as
either a stand-alone device or as the second reaction chamber of
the present invention with the plasma discharge 99 shown between
the centrally located plasma discharge electrode 131 and the
relatively open mesh plasma discharge screen 133. As described
earlier, its function is the treatment of pollutants such as oxides
of nitrogen (NO.sub.x) and ozone (O.sub.3). Its construction and
method of operation is exactly the same as that described in the
detailed description of FIG. 1 with the only potential difference
being the option of placement for the oxides of nitrogen pollutant
level sensor 141. Hot ionized gases would be found in the exhaust
gas flow free of hydrocarbon based pollutants 126 coming from the
plasma oxidization reaction chamber 103. But when the plasma
reduction reaction chamber 127 is used as a stand-alone device it
is possible to place the oxides of nitrogen pollutant level sensor
141 at the inlet because it would not be confused by hot ionized
gases in the exhaust being treated.
[0100] FIG. 4A shows the electron return section of the plasma
reduction reaction chamber 127 with an electron return anode
hemispherical screen 161 installed in each of the four positions
originally occupied by the electron return anode conical screens
147.
[0101] FIG. 4B shows the electron return section of the plasma
reduction reaction chamber 127 with an electron return anode spiral
screen 163 installed in each of the four positions originally
occupied by the electron return anode conical screens 147. The
electron return anode spiral screens 163 shown have a greater
surface area than either the electron return anode conical screens
147 or the electron return anode hemispherical screen 161 and may
be called for if it turns out that more surface area is needed for
the gradual, complete, and even return of electrons.
[0102] FIG. 4C shows an electrically resistive material electron
return anode spiral screen 165 taking the place of an entire series
of electron return screens of the other types. This is done by
being made of a resistive material and by having the end of it that
is at the very end of the treatment process connected without any
resistor to the negative output lead 149 coming from the direct
current power supply 139. The placement of the electrical
connection establishes a voltage gradient across the length of the
electrically resistive material electron return anode spiral screen
165. This voltage gradient has its lowest voltage being at its end
closest to the electrically isolated gas mixing and charge
distribution spiral screen 143 (shown and described in reference to
FIG. 1, and shown in FIG. 3) and its highest voltage right at the
end of the treatment process. The purpose of voltage gradient is to
affect a gradual return of electrons thus avoiding a concentration
of energy release from electron return discharge leading to oxides
of nitrogen (NOx) re-forming in the exhaust gases.
[0103] Another option (not shown) for an even more gradual return
of electrons is to have a series of the electrically resistive
material electron return anode spiral screens 165 connected to the
negative output lead 149 coming from the high voltage direct
current power supply 139 through a set of resistors such as those
used with the electron return anode conical screens 147. In this
arrangement, the electrically resistive material electron return
anode spiral screens 165 closest to the electrically isolated gas
mixing and charge distribution spiral screen 143 is connected to a
high value current limiting resistor 151. The actual resistance for
an operational unit being determined by the specific conditions of
the application, but for purposes of illustration in this
description will be referred to as X ohms. The high value current
limiting resistor 151 is in turn connected to a negative output
lead 149 coming from the high voltage direct current power supply
139. The electrically resistive material electron return anode
spiral screens 165 that comes next is connected to a medium value
current limiting resistor 153 with a resistance of 2/3 X ohms which
is in turn connected to the negative output lead 149 coming from
the high voltage direct current power source 139. The electrically
resistive material electron return anode spiral screens 165 that
follows the previous two is connected to a low value current
limiting resistor 155 with a resistance of 1/3 X ohms which is in
turn connected to the negative output lead 149 coming from the high
voltage direct current power supply 139. Finally, to insure that
all of the electrons are returned and that the electrical charge of
the gases leaving the present invention is neutral, the
electrically resistive material electron return anode spiral
screens 165 that comes at the end of the process is connected
directly to the negative output lead 149 coming from the high
voltage direct current power source 139 without any resistor. Of
all of the options presented for electron return described, this
one offers the most gradual return capability.
[0104] FIG. 5 shows a schematic used for both the plasma generation
circuit 115 connected to the plasma discharge anode device 109 and
the plasma generation circuit 135 connected to the plasma discharge
cathode device 129 (shown in FIG. 1). This circuit is controlled by
a square wave generator 167 through a control signal input line 169
that is connected to the gates of a set of three matching power
Metal Oxide Surface Field Effect Transistors 171 (henceforth
referred to as the power MOSFETs 171). These three power MOSFETs
171 are the switches that when turned on allow current to flow from
a direct current power source 173 through a primary winding 175 of
a high voltage transformer labeled T1 177. The three power MOSFETs
171 connect the other end of the primary winding 175 to a direct
current ground connection 179 through a 0.2 ohm resistor 181.
Between the low voltage side of the primary winding 175 and the
direct current ground connection 179 are a capacitor of 4700
picofarads 183, another capacitor of 4700 picofarads 185 and a
capacitor of 2200 picofarads 187 and a high amperage diode 189.
When used in this circuit, the high amperage diode 189 acts as a
free wheeling diode.
[0105] A capacitor of 0.047 microfarads 191, a capacitor of 0.1
microfarads 193, and a capacitor of 2200 picofarads 195 are
connected across the leads to the primary winding 175. Also
attached to the power side of the primary winding 175 connected to
the direct current ground connection 179 are a capacitor of 4700
picofarads 197, a capacitor of 2200 picofarads 199, a capacitor of
0.1 microfarads 201, and a capacitor of 1.0 microfarad 203.
[0106] Connected to a secondary winding 205 of the high voltage
transformer labeled T1 177 are two plasma discharge circuit output
lines 207. These lines are each in turn connected to either the
plasma discharge anode device 109 (shown in FIG. 1) or to the
plasma discharge cathode device 129 (shown in FIG. 1) depending
which reaction chamber the plasma generation circuit 115, 135 is
used with. The plasma discharge circuit output line 207 that is
connected to the relatively open mesh plasma discharge screen 113,
133 (shown in FIG. 1) is also connected to one of the outputs from
the high voltage direct current power source 119, 139 (shown in
FIG. 1). This connection is used to introduce the direct current
high voltage component into the plasma discharge 99 (shown in FIGS.
2A, 2B, and 3) needed to produce either the plasma oxidization or
plasma reduction effect inside the reaction chamber.
[0107] When the power MOSFETs 171 are turned on by the individual
pulses of the square wave signal from the square wave generator 167
through the control signal input line 169 more than just the
electricity from the direct current power source 173 flows through
the primary winding 175 of the high voltage transformer labeled T-1
177. Four capacitors 197, 199, 201, and 203 of different values
also discharge through the primary winding 175 of the high voltage
transformer labeled T-1 177.
[0108] These four capacitors 197, 199, 201, and 203 are also set up
as a resonant tank circuit with the primary winding 175 which
acting as the inductor in the tank circuit. Since each of the four
capacitors 197, 199, 201, and 203 have a different value, four
resonant tank circuits are set up, each one resonating at a
different frequency. When the power MOSFETs 171 are turned on, the
high amperage diode 189 plays an important role in this resonance
in that the high amperage diode 189 and the power MOSFETs 171 allow
current to flow in both directions during resonance through the
primary winding 175. When the power MOSFETs 171 are turned off,
resonance can occur for another half cycle through the high
amperage diode 189.
[0109] This does not however stop circuit resonance because at this
point the three capacitors 191, 193, and 195 (each of a different
value) that are across the leads to the primary winding 175 take
over and continue to resonate in the resonant tank circuit they
form. Since these three capacitors 191, 193, and 195 all have
different values, three different tank circuits are formed that
continue to resonate at three different frequencies even after the
power MOSFETs 171 are turned off.
[0110] Also contributing to the collection of various resonant
frequencies are the three capacitors 183, 185, and 187 that are
connected between the lead of the primary winding 175 opposite its
lead connected to a direct current power source 173 and the direct
current ground connection 179. Although the values of two of the
capacitors 185 and 187 are the same, it was determined empirically
that this combination produced the most vigorous plasma
discharge.
[0111] It should be appreciated that there are other equally
effective point-to-point plasma discharge circuits that could be
used within the spirit and intention of the invention that can
accomplish the same function.
* * * * *