# US 7,608,796 B2 · Plasma generating electrode and plasma reactor

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- Number: US 7,608,796 B2
- Document ID: US7608796B2
- Status: Granted
- Kind: B2
- Application number: 11/389,010
- Filed: 2006-03-27
- Published: 2006-10-05
- Granted: 2009-10-27
- Earliest claimed: 2005-03-30
- Assignees: NGK Insulators, Ltd.; Honda Motor Co., Ltd.
- Inventors: Yasumasa Fujioka; Atsuo Kondou; Takeshi Sakuma; Masaaki Masuda; Kenji Dosaka; Kazuhiro Kondo
- Web page: https://patentgrep.com/patent/US7608796B2

## CPC

- H01J 37/32431: {Constructional details of the reactor}
- B01D 53/32: by electrical effects other than those provided for in group B01D61/00
- B01D 53/92: of engine exhaust gases (exhaust {or silencing} apparatus {for internal combustion engines, machines or engines in general}, having means for purifying, {rendering innocuous} or otherwise treating exhaust gases F01N3/00)
- B01D 2259/818: Employing electrical discharges or the generation of a plasma
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

A plasma generating electrode capable of generating plasma with a high energy level by using a small amount of electric power is provided. The plasma generating electrode includes at least a pair of unit electrodes including a unit electrode as an anode and a unit electrode as a cathode, and can generate plasma by applying voltage, the unit electrode as an anode and the unit electrode as a cathode being disposed facing each other, and at least the unit electrode as an anode having a plate-like ceramic dielectric and a conductive film disposed in the ceramic dielectric, wherein the unit electrode as a cathode can emit secondary electrons in a number five times or greater than the number of cations (primary particles) which it receives when the cations produced in the process of plasma generation collide therewith.

## Claims

### Claim 1

A plasma reactor comprising:
a plasma generating electrode that generates plasma by applying voltage; and
a casing having a passage (gas passage) for a gas containing a specific component formed therein,
wherein, when the gas is introduced into the gas passage of the casing, the specific component contained in the gas reacts with the plasma generated by the plasma generating electrode,
wherein the plasma generating electrode comprises at least a pair of unit electrodes including a unit electrode as an anode and a unit electrode as a cathode,
the unit electrode as an anode and the unit electrode as a cathode being disposed facing each other, and at least the unit electrode as an anode having a plate-like ceramic dielectric and a conductive film disposed in the ceramic dielectric,
wherein the unit electrode as a cathode emits secondary electrons in a number five times or greater than the number of cations (primary particles) which it receives when the cations produced in a process of plasma generation collide therewith,
wherein the unit electrode as a cathode contains at least one material selected from the group consisting of a beryllium-copper alloy, silver-magnesium alloy, aluminum-magnesium alloy, nickel-beryllium alloy, cesium oxide, binary oxide of barium and strontium, zinc sulfide, and calcium tungstate.

### Claim 2 (depends on 1)

The plasma reactor according to claim 1, wherein the ceramic dielectric of the unit electrode as an anode contains at least one ceramic selected from the group consisting of alumina, mullite, ceramic glass, zirconia, cordierite, silicon nitride, aluminum nitride, and glass.

### Claim 3 (depends on 1)

The plasma reactor according to claim 1, wherein the conductive film of the unit electrode as an anode contains at least one metal selected from the group consisting of tungsten, molybdenum, manganese, chromium, titanium, zirconium, nickel, iron, silver, copper, platinum, and palladium.

### Claim 4 (depends on 1)

The plasma reactor according to claim 1, further comprising one or more pulse power supplies for applying voltage to the plasma generating electrode.

### Claim 5 (depends on 4)

The plasma reactor according to claim 4, wherein the pulsed power supply includes with at least one SI thyristor.

### Claim 6 (depends on 1)

The plasma reactor according to claim 1, wherein the conductive film is embedded within the ceramic dielectric.