Discharge Methods Utilizing Tubular or Cylindrical Electrodes
Patent #906,468--December 8, 1908
Steynis, Jan. Process for the Production of Ozone.
This patent is for an ozone generator which is made up of three tubular electrodes separated by dielectric plates made of glass. The electrodes are attached to a transformer which provides alternating current; this alternating current causes a silent discharge or streaming electrical discharge between the electrodes in the space between the electrodes. This space between the dielectrics and the electrodes is the ozonizing chamber into which an oxygen-containing gas is admitted. The discharge causes oxygen to be converted to ozone, and the produced ozone exits the generator via an outlet duct. A cooling liquefied gas is introduced into the hollow tube electrodes and chills the electrodes. The temperature of the gas to be ozonized remains constant as it passes through the generator because each short period of ozonization is followed by a period of cooling. This maintenance of temperature allows for the temperature to remain at the point for optimum ozone production throughout the process.
Patent #1,157,859--October 26, 1915
Freet, William O. Ozone-Generator.
This concentric tube electrode/corona discharge ozone generator uses ammonia or brine as a coolant. The apparatus uses mica as a dielectric between a stationary inner metallic cylindrical electrode and a removable outer metallic cylindrical electrode. The outer electrode is removable so that it may be easily cleaned or replaced if it is damaged in repeated use of the ozone generator.
Patent #1,454,219--May 8, 1923
Goedicke, Richard. Ozone-Generating Apparatus.
This patent is for an ozone generator with concentric tubular electrodes located inside one another and spaced from one another. The electrodes are separated from each other by a glass tube which serves as a dielectric. The outer electrode is also surrounded by a glass tube. An electrical discharge between the electrodes ozonizes air which is fed into the generator. The inventor claims that water-cooling devices of this sort is insufficient due to problems such as forgetting to turn the water on and leaks in the water lines. To avoid these problems, this invention uses air to cool the electrodes. Air flows through the generator in the space inside the innermost tube of the apparatus and through the space between the outer electrode and a glass tube which surrounds it. The cooling air is also ozonized to a degree by the discharges. This partially ozonized air is recirculated through the apparatus and is finally collected with the produced ozonized air to be purified.
Patent #1,505,669--August 19, 1924
Quain, John Robert. Apparatus for the Production of Ozone.
This patent is for a generator which produces ozone to be used in the antiseptic treatment of wounds and for general oxidizing purposes. The ozonizer consists of concentric tube electrodes separated by a silica dielectric. Ozone is produced in the chamber between the electrodes by electrical discharge. The outer electrode is coated with silica to prevent erosion of the electrode by ozone. The apparatus is fitted with a nozzle for applying ozone as an antiseptic to wounds.
Patent #3,730,874--May 1, 1973
Trüb, Hannes. Tubular-Shaped Ozonizer Possessing Cooled Inner Electrode.
This patent is for an ozone generator which consists of a tubular inner electrode and a tubular outer electrode, both made of aluminum. The electrodes are separated by a dielectric tube made of thin walled glass with a metallic coating on the inner wall. The electrodes and the dielectric tube are arranged concentrically with spaces between the inner electrode and the dielectric tube and between the dielectric tube and the outer electrode. Water or some other cooling fluid is fed into the space between the inner electrode and the dielectric tube. The space between the dielectric tube and the outer electrode serves as an ozonizing chamber. An oxygen-containing gas is fed into this ozonizing chamber, and the oxygen is converted to ozone by an electrical discharge between the inner and outer electrode.
Patent #3,833,492--September 3, 1974
Bollyky, L. Joseph. Method of Producing Ozone.
This patent outlines an ozonizing apparatus consisting of a several ozone generating cells of the concentric tube electrode type inside an electrically non-conductive container which is filled with a cooling dielectric liquid such as silicone oil. The container has an inlet and an outlet for the cooling liquid which continually passes through the container cooling the ozone generating cells. The ozone generating cells consist of an inner metal tube, which forms one electrode. Water or another cooling liquid flows through the metal tube. The tube is surrounded by another tube made of a dielectric material such as glass and is spaced radially from the inner metal tube. The outer surface of the glass tube is coated with a metal which forms the outer electrode. An oxygen-containing gas passes through the space between the dielectric and the inner metal tube, and an electric discharge between the two electrodes excites the oxygen in the space to ozone which exits the apparatus through an outlet.
Patent #3,921,002--November 18, 1975
Williams, Laurence O., et al. Ozone Generator.
This patent is for a cryogenically cooled corona discharge ozone generator. The ozone generator outlined in the patent is cylindrically shaped with an inlet for oxygen at one end and an outlet for liquid ozone at the other end. The temperature of the generator is maintained below the boiling point of ozone so that the ozone formed by the corona discharge is condensed to a liquid before it exits through the generator’s outlet. The outlet is packed with glass beads to prevent the explosive decomposition of ozone and is maintained at a thermal gradient so that gaseous ozone exits from the generator in a controllable fashion.
Patent #3,967,131--June 29, 1976
Slipiec, Romuald E., et al. Corona Discharge Ozone Generating Unit.
This patent is for an ozone generator comprising concentric tube electrodes. The generator consists of three dielectric tube/electrode assemblies enclosed in a cylindrical casing made of polyvinyl chloride or another suitable insulating material. The dielectric tube/electrode assemblies consist of dielectric cylindrical tubes made of glass or a similar material, and electrodes which are connected to high voltage terminals which are connected to opposite ends of a high voltage transformer. The assembly is cooled by the air which is to be ozonized. The inner electrode is on the inner surface of the dielectric tube, and is made of a flexible, conductive piece of metal mesh material which initially does not have the same curvature as the dielectric tube. The outer electrode is made of a rigid metal mesh and is spaced from the dielectric tube forming a gap in which air is ozonized by a corona discharge between the two electrodes. The heat produced from the discharge between the electrodes causes the inner electrode to expand into contact with the inner surface of the dielectric tube.
Patent #4,025,441--May 24, 1977
Tabata, Norikazu, et al. Ozone Generating Apparatus.
This patent is for an ozone generating apparatus of the concentric tube electrode type. The invention consists of an inner metallic electrode surrounded by a dielectric tube. The dielectric tube is cooled by a mixture of deionized water and a glycol such as ethylene glycol or propylene glycol. The tube is equipped with an inlet and an outlet for the coolant liquid so that the liquid is continually circulated through the tube. A metallic cylindrical grounded electrode surrounds the dielectric tube and is separated from it by an annular space. This metallic cylindrical grounded electrode is cooled by water which enters through an upper inlet and exits through an outlet positioned near the lower portion of the apparatus. Air or oxygen is fed into the apparatus and enters the space between the dielectric and the outer metallic electrode. An electric discharge between the two electrodes in this space causes the conversion of oxygen gas to ozone. The ozonized gas exits through an outlet and is collected. This apparatus differs from previous ozonizers of the same type which only provided for cooling of the outer metallic electrode because both the dielectric tube and the outer metallic electrode are cooled. This cooling prevents ozone from being converted back to oxygen by the heat of the discharge.
Patent #4,048,668--September 13, 1977
von Bargen, John D. Electrically Driven High Voltage Ozonator.
This patent outlines an ozone generator of the concentric tube electrode type which converts oxygen to ozone by exposing the oxygen in the space between the two electrodes to a corona discharge generated between the two concentric electrodes. The inner electrode is a hollow stainless steel tube into which oxygen gas is fed. The inner electrode is perforated with four holes through which the oxygen gas escapes into the space between the inner electrode and a concentric glass dielectric tube. This dielectric tube is in contact with the outer ground electrode which is also made of stainless steel. The oxygen gas in the gap between the dielectric tube and the inner electrode is subjected to corona discharge which is produced by applying a potential of 30 to 50 kV between the inner electrode and the ground electrode. This discharge converts the oxygen to ozone. By feeding the oxygen gas into the interior of the hollow inner electrode, the gas serves to dissipate excess heat generated by the discharge.
Patent #4,049,552--September 20, 1977
Arff, John H. Ozone Generating System.
This patent describes a technique for using the ozone generated from a discharge ozone generator to purify water. Specifically, the process described in this patent specifies that the water treated with this process produces water with purity high enough such that it can be used as a substitute for distilled water or as rinse solution for electroplating. The ozonizer is of the general tubular type. Included in the process is a method for introducing the ozone produced by the ozonizer into a captured body of water, and a filtration system for filtering out the fine particles produced by ozone purification. It is claimed that this method of producing purified water removes not only dissolved metals but also bacterial and viral contaminants.
Patent #4,051,045--September 27, 1977
Yamamoto, Yoshihiko, et al. Ozone Generating Apparatus.
This patent outlines an ozone generator with concentric tube electrodes. A glass tube which serves as a dielectric is surrounded by a metallic cylinder which is the outer electrode. An annular space exists between the dielectric tube and the metallic cylinder. A second, inner electrode is formed by adhering a vaporized metal to the inner surface of the dielectric tube. The inner electrode is connected to a high voltage terminal which supplies a rectangular waveform alternating current to the ozone generator. A discharge is formed in the space between the dielectric tube and the outer electric, and the oxygen in the space is converted to ozone. The patent claims that this rectangular waveform alternating current is more suitable for
ozone production than the typical sinusoidal waveform alternating current employed in previous methods.
Patent #4,079,260--March 14, 1978
Dmietriev, Andrei V., et al. Ozone Generator.
This patent describes an ozone generator which consists of an inner metallic cylindrical electrode with a dielectric coating of glass enamel on its outer surface (see Figure 3). Spaced from the dielectric coating is an outer electrode, two metal plates which envelope the inner electrode with the dielectric coating. The electrodes are liquid-cooled, and an electric discharge is initiated between the electrodes through an oxygen containing gas. The ozonizer has an inlet and an outlet for the cooling liquid so that it can continuously circulate through the apparatus, and it also has an inlet for oxygen or oxygen-bearing gas and an outlet for ozone-enriched gas.
igure 4: Schematic Diagram of Apparatus Outlined in US Patent #4,079,260Patent #4,101,783--July 18, 1978
Hutter, Felix J. Ozone Generator.
This patent describes a concentric tube type ozone generator which consists of a twin-walled dielectric tube with a space between the two walls in which oxygen is converted to ozone by an electrical discharge in the space. The inner wall of the dielectric tube is in contact with an inner electrode which is made of a metallic foil such as aluminum foil or some other thin conductive material. The outer electrode is made of the same substance and is in contact with the outer wall of the dielectric tube. Oxygen gas or another oxygen-containing gas is injected into the space between the walls of the dielectric tube through an inlet, and an electrical discharge between the two electrodes formed by placing a voltage of about 20 kV across the electrodes converts this oxygen to ozone. The ozone-enriched gas exits the device through an outlet near the bottom of the dielectric tube and is either collected or may be sent to another ozone generator so that the remaining oxygen may be converted to ozone. An advantage of this device is that it incorporates a space between the inner walls of the dielectric tube in which a supply of a liquid insulating medium such as oil is housed. This oil prevents the flow of "creep currents," currents which result from dust on the walls of twin-tube type ozone generators and flow along the shortest path between the inner and outer electrodes. These creep currents can result in short circuits, damage to the high-voltage source, and injury to nearby persons. The reservoir containing an insulating medium prevents these creep currents.
Patent #4,123,664--October 31, 1978
Yamamura, Takashi, et al. Ozone Generating Apparatus.
The ozone generator described in this patent consists of a glass dielectric tube surrounded by a metallic cylindrical electrode which is spaced from the glass tube. An inner metallic electrode is adhered or vapor-metallized on the inner surface of the glass dielectric tube. This inner electrode is connected to a high voltage terminal. A power source connected to the high voltage terminal supplies a rectangular waveform alternating current between the two discharge electrodes. The resulting discharge between the two electrodes converts oxygen in the space between the dielectric tube and the outer electrode to ozone. This type of waveform is ideal for production of ozone because it reduces thermal and mechanical stress on the glass dielectric tube because its voltage waveform changes in proportion to the period of the current.
Patent #4,128,768--December 5, 1978
Yamamoto, Yoshihiko, et al. Ozone Generating Apparatus.
This patent is for a glass discharge tube ozone generator. The purpose of this invention is to increase the conversion of oxygen to ozone in commercial ozone generators by improving the discharge density between the discharge electrodes. To accomplish this, the generator described in this patent has been electrically engineered to convert alternating sinusoidal waveform current to a rectangular waveform alternating current. Included in the patent is a transformer that is designed to use a commercial power supply.
Patent #4,159,971--July 3, 1979
Gneupel, Arthur. Ozone Generator.
This patent is a design for an electric discharge tubular ozone generator that uses a mesh inner electrode, a solid dielectric, and a metallic foil outer electrode. As outlined in the patent, the advantage of the described ozonizer lies in the helically shaped grooves that extend in the axial direction and form a throughpass channel for the formation of ozone around the inner tube electrode. It is claimed in the patent that the helical grooves result in an increase in the efficiency of the conversion of an oxygen containing gas to an ozone/gas mixture. The design of the ozonizer also includes a means of air cooling the inner electrode by moving air through a hollow inner tube and a means of air cooling the outer electrode by attaching cooling flanges.
Patent #4,216,096--August 5, 1980
Pare, Maurice, et al. Ozone Generation Device and Electrode.
This patent is a design for a silent discharge ozone generator of the tubular kind. While it is not mentioned in the claims section of the patent, the discussion mentions that the electrical engineering of this ozone generator is such that it will allow an increase in voltage over other conventional designs and reduce electrode degradation by arcing and sparking. The patented design differs from other conventional tubular electrodes in the electrical engineering of an electrically conductive cap positioned in contact with the inner electrode and at one end of the generator tube. The cap is cylindrically shaped and extends into a conical portion. It is claimed in this patent that the design of the cap causes a reduction in the concentration of lines of force in its area.
Patent #4,234,800--November 18, 1980
Kenly, William L. Ozone Generator.
This patent is for a modular ozone generator in which ozone is formed by corona discharge. The ozonator is tubular in design and consists of a central fluid-cooled metal electrode surrounded by an intermediate tubular dielectric material that has an outer metallic coating and is designed to serve as an outer electrode. Furthermore, the outer dielectric/electrode is designed to be surrounded by a jacket through which a cooling oil circulates. The main purpose of this design is to simplify the construction of the general type of ozone generator described by the apparatus and to reduce construction costs and breaking.
Patent #4,383,976--May 17, 1983
Notaro, Salvador P. Ozone-Generating Assembly.
This patent is a design for an electric discharge ozone production apparatus that makes use of a plurality of generator tubes that are mounted parallel with respect to one another and are connected together by perpendicular rods that serve to provide electrical connections and support to the generator tubes. The individual generators are made up of rod electrodes on the interior of the tube that comprise the inner tube electrode of the generator and the tube is covered by a cylindrical casing of metal mesh that comprises the outer tube electrode. Air or oxygen is fed into the tops of each of the generator tubes by tubing that is connected to an air distributor that has the potential to feed gas into a number of discharge tubes simultaneously. The lower rod of the discharge tubes which serves to provide both support and electrical connection to the individual discharge tubes is hollow. Gas that is fed into the tops of the ozone generators exits the generator by a connection between the generator and the hollow bottom support rod. In this manner, the ozone that is produced by the assembly can be collected at one location and then be fed to any desired location. The advantages of this apparatus over other industrial scale ozone generators is that the use of a battery of smaller ozone generators instead of a "giant ozonizer" avoids the problems associated with the high voltages that are required by the "giant ozonizers."
Patent #4,411,756--October 25, 1983
Bennett, Douglas L., et al. Boiling Coolant Ozone Generator.
This patent is a design for a boiling coolant corona discharge ozone generator. Oxygen is fed into a cylindrical electrode/dielectric/electrode assembly where the corona discharge causes the reaction that converts some of the oxygen to ozone. The oxygen/ozone mixture is then directed out of the generator. The reaction chamber is housed inside a rectangular assembly which contains a cooling fluid and a condenser. The heat created by the ozonizer is transferred to the cooling fluid which in turn boils. The gas phase coolant is then condensed by a water fed condenser so that it is recycled. This patent claims that the cooling method increases the efficiency of the conversion of oxygen to ozone.
Patent #4,417,966--November 29, 1983
Krauss, Ralf, et al. Apparatus and Method of Producing Ozone.
This patent is a design for both an apparatus and method for a geometrically cylindrical ozone generator that uses a "plasma electrode", a second annular electrode, and an insulating material between the two electrodes. The "plasma electrode" as described in the patent is formed by sealing a metal electrode inside a glass/Pyrex/quartz tube that has an internal atmosphere which consists of an ionizable gas. Between the "plasma electrode" and the outer annular electrode there is a space containing an air inlet and outlet that allows for an oxygen containing gas to flow and be converted to an ozone/gas mixture. As mentioned in the discussion of this patent, this type of generator shows an increase in the efficiency of the conversion of oxygen to ozone. Also discussed are several advantages that this design has over other discharge ozone generators, including but not limited to the production of less heat and the protection against electrode oxidation.
Patent #4,461,744--July 24, 1984
Erni, Peter, et al. Apparatus for Generating Ozone by an Electrical Discharge.
This patent outlines an apparatus for generating ozone by electric discharge. The apparatus is a tube ozonizer consisting of an outer metal tube that forms one electrode with a glass tube inside and an electrically conductive layer coating the inside of the glass tube and forming the second electrode. The apparatus uses pulse discharges to form ozone by creating a plate-like spark gap. According to the claims, the pulse production method leads to an increase in the efficiency of the conversion of oxygen to ozone, and it is possible to convert conventional AC ozonizers to pulse operation.
Patent #4,504,446--March 12, 1985
Kunicki, Wojciech, et al. Ozone Generator.
This patent is an outline for a tubular ozone generator. The generator uses a discharge method for the production of ozone in which an outer metal tube forms one electrode, a glass tube forms a dielectric, and a metal coating on the interior of the glass tube forms the second electrode. The discharge method uses a high-frequency AC source. Included in the design is a method for air cooling the inner electrode by using a heat dissipating metal body inside the inner electrode which also has the potential for serving as the electric connection for connecting the inner electrode to the voltage source, and a method for air cooling the outer electrode by attaching metal cooling flanges.
Patent #4,614,573--September 30, 1986
Masuda, Senichi. Method for Producing an Ozone Gas and Apparatus for Producing the Same.
This patent is a design for an oxygen fed ozone generator that uses an electric discharge method for the production of ozone. As discussed in the patent, the design of the discharge device is in the form of two cylindrical electrodes that have an alumina ceramic dielectric between them. This design is unique in that it includes a method for increasing the density of the oxygen gas that is in the ozonizer. The density of the gas in the ozonizer is increased by means of a pressurizing pump and two types of cooling fins that are attached to the electrodes. Of the fins that are attached to the electrodes, some of them are air cooled and some are designed to allow for a cooling fluid to circulate in the interior of the fin. It is claimed in this patent that the increase in the density of oxygen in the ozonizer results in a 5% conversion efficiency of oxygen to air.
Patent #4,640,782--February 3, 1987
Burleson, James C. Method and Apparatus for the Generation and Utilization of Ozone and
Singlet Oxygen.
This patent is an outline for both a method of producing ozone and singlet oxygen and a process to use the ozone and singlet oxygen to sterilize surgical instruments/containers and kill pathogens on the surface of the skin. The production process involves circulating oxygen into a cylindrical discharge area formed by a cylindrical outer electrode, a cylindrical solid dielectric spacing , and a cylindrical interior electrode. After the oxygen gas flow passes through the reaction chamber, the ozone, singlet oxygen/oxygen flow is directed towards the instruments/containers for sterilization or towards the surface of skin for the purpose of killing pathogens.
Patent #4,650,573--March 17, 1987
Nathanson, Roger T. Ozone Generator Water Treatment.
This patent is for an ozone generator consisting of a metal "brush" which forms an inner electrode in a concentric tube electrode arrangement. The brush is surrounded by an ozonizing space which is bounded by a Pyrex glass cylinder which functions as a dielectric between the brush electrode and an outer cylindrical electrode made of sheet metal. Corona discharge between the two electrodes converts oxygen in air which is fed into the apparatus to ozone which is collected outside the ozonizing chamber. The patent involves a method for water purification using the produced ozone. The method entails a means of automatically activating the ozone generator in response to water flowing through the use of an aspirator in conjunction with a faucet or in response to activation of a well pump.
Patent #4,656,010--April 7, 1987
Leitzke, Ortwin, et al. Device for Producing Ozone.
This patent is a design for a tubular high voltage discharge ozone generator. This design is unique in that it uses a small inner electrode with a diameter that is one-half the diameter of the outer electrode. The design for the inner electrode includes diameters from 0.5 to 10 mm, and the inner electrode is constructed from either a single wire or a plurality of wires. A plastic, glass, or Pyrex dielectric separates the inner electrode from the outer electrode and creates the region through which oxygen or oxygen containing gas flows. A second design is included in this patent which uses a generator built along the same principles but with parabolic shaped electrodes to allow a cooling fluid to circulate along the exterior of the outer electrode. This patent claims that this type of ozone generator can be used to create a uniform charge density between the inner and outer electrode as opposed to other types of tubular discharge ozone generators and thereby increase the efficiency of the process which converts oxygen to ozone.
Patent #4,690,803--September 1, 1987
Hirth, Michael. Ozone Generator.
This patent is an improvement of the concentric tube electrode corona discharge ozone generator. The inner metallic electrode is covered with a dielectric material of titanium dioxide ceramic or of plastic filled with a dielectric powder. Between the dielectric material and the outer electrode is a discharge gap in which corona discharge between the two electrodes converts oxygen to ozone. The surface of the dielectric layer facing the discharge gap is coated with a protective glass or ceramic layer of silicon dioxide. This protective coating makes the ozone generating apparatus more resistant to stresses caused by the discharge.
Patent #4,696,800--September 29, 1987
Sasaki, Toshihiko, et al. Ozone Generating Apparatus.
This patent is a design for a safe and compact high voltage ozone generator. The design of the generator includes a casing in which all parts of the ozone generator are mounted. A transformer is mounted inside the casing and is connected to the discharge apparatus. The outer electrode of the discharge apparatus is in the form of a rectangle in which one end is closed and the other end left open. The inner electrode consists of a parabolically shaped glass discharge tube with an interior coating of an electrically conductive material. Included in the design of the electrodes are grounding connections, transformer connections, a gas inlet, and a gas outlet.
Patent #4,725,412--February 16, 1988
Ito, Hajime. Ozone Generator.
This patent is a design for an electric discharge ozone generator that is engineered so that the ozone/gas mixture produced by the generator is not contaminated with particles that are the result of electrode degradation. This type of generator is designed to be used in industrial situations that require a clean room. The apparatus described by this patent is formed by two electrodes that are made by starting with either quartz or silica tubes and depositing an electrically conductive material on the exterior of the outer electrode and the interior of the inner electrode by metallic vapor deposition. In this manner, the discharge area between the two electrodes is not in contact with the metallic electrically conductive material that forms the electrodes. In addition, the outer electrode coating is designed to be made from a water resistant material so that electrically nonconductive pure water can circulate in direct contact with this electrode for cooling purposes.
Patent #4,764,349--August 16, 1988
Arff, John H., et al. Ozone Generator.
This patent is a design for a high voltage electric discharge ozone generator. The design itself consists of a sealed glass tube that is filled with a gas that when subjected to high voltage will produce a radiation of energy through the tube. A high voltage on the interior of the glass tube is accomplished by longitudinally mounting a conductive metallic rod inside the glass tube such that the rod perforates one end of the tube while maintaining an atmospheric seal. The outer electrode of the ozone generator has undergone extensive engineering and does not resemble the common plate or tube electrode that is characteristic of many ozone generators. Instead, the outer electrode is a sleeve of flute like perforations that surrounds the glass tube. It is on the interior of the flute-like perforations that ozone is formed by this apparatus. This design is intended to provide a simplistic and inexpensive method for producing ozone.
Patent #4,877,588--October 31, 1989
Ditzler, Lee C., et al. Method and Apparatus for Generating Ozone by Corona Discharge.
This patent is for a corona discharge ozone generator that is designed to add the ozone produced from an oxygen containing gas to a body of captured water. Furthermore, the outlined apparatus also includes a method for monitoring and controlling the content of ozone in the captured water by means of a device that reads the oxidation-reduction potential of the water. The outlined apparatus consists of a metallic inner electrode connected to electrified radial brushes that come into contact with bands of dielectric material that alternate with cooling regions. The metallic inner electrode defines the axis of the ozone generating apparatus which is of cylindrical design. The alternating corona discharge and cooling regions are achieved by surrounding the circular dielectric bands in contact with the radial brushes with an outer cooling wall that is in contact with a coolant liquid such as water.
Patent #4,886,645--December 12, 1989
Fischer, Melchior, et al. Ozone Generator.
This patent is for a stack type modular discharge ozone generator. As described in the patent, the outer electrodes are of the water cooled tubular type. Furthermore, the tubular outer electrodes are vertically stacked with respect to one another while the axis of each individual tubular outer electrode is horizontal with respect to the tank that contains all of the inner and outer electrodes. The modular inner electrodes are formed from a dielectric material and a metallic coating. A number of the modular inner electrodes are placed in series in between two outer electrode plates to form a discharge gap for the production of ozone. The purpose behind the construction of this ozone generator was to provide a means for producing the quantities of ozone needed in industrial situations.
Patent #4,960,569--October 2, 1990
Fovell, Richard C., et al. Corona Discharge Ozonator with Cooled Flow Path.
This patent is for an ozone generator of the concentric tube electrode corona discharge type (see Figure 4). The invention consists of the typical inner metallic cylindrical electrode made of tungsten or stainless steel, typical outer electrode made of aluminum, steel or copper, and the typical dielectric made of borosilica glass. The ozonation chamber is formed between the dielectric and the outer electrode; corona discharge in this chamber formed by applying a high voltage across the electrodes ozonizes the oxygen within the chamber. This invention also comprises a plurality of spherical solids made of an ozone-resistant metal which line the ozonation chamber which is the space between the outer electrode and the dielectric. The spheres function to transfer heat by direct thermal conduction from the hot dielectric material and inner electrode to the cooler outer electrode.
Figure 5: Diagram of Apparatus Detailed in US Patent #4,960,569
Patent # 4,981,656--January 1, 1991
Leitzke, Ortwin. Device for the Production of Ozone.
This patent discusses an apparatus for production of ozone involving two electrodes which are concentric tubes. A silent electrical discharge oxidizes gases in a chamber between the two tubes to produce ozone. The internal electrode is a voltage-conducting hexagonal bar or hexagonal tube, the outer electrode is a circular metal tube which is either water-cooled or air-cooled, and the ratio of the diameter of the external electrode to the diameter of the internal electrode is not greater than two. The inner electrode is surrounded by a gas discharge chamber; this gas discharge chamber is surrounded by a dielectric which is a glass tube. The dielectric is then surrounded by another gas discharge chamber which is in contact with the external electrode. In previous inventions of similar design, the ratio of the diameters was greater than two. The inventor claims that the smaller ratio (which reduces the distance between the two electrodes) results in a lesser field intensity or voltage required for the silent electrical discharge; this decrease in field intensity or voltage required to produce the discharge increases the degree of efficiency of the type of device consisting of concentric tubular electrodes.
Patent #5,004,587--April 2, 1991
Tacchi, Ernest J. Apparatus and Method for Ozone Production.
This patent details an ozonizer chamber consisting of a flexible high tension electrode with supporting spacers which are enclosed within a flexible dielectric tubing. The dielectric tubing separates the high tension electrode from a fluid counter-electrode which surrounds the outside of the dielectric tube. A dry oxygen-bearing gas passes through and is stored inside the tube; electrical discharges occur between the high tension electrode enclosed by the dielectric tube and the fluid counter-electrode which completely surrounds the dielectric tube, and ozone is produced by oxidization of the oxygen-bearing gas. The fluid counter-electrode used is of high electrical conductivity so that it functions as an electrolytic power connection to the gas discharge chamber by changing electron current to ion current and is also a means of heat removal. The ability of the fluid counter-electrode to absorb thermal energy by conduction is an advantage since elevated temperatures caused by the electrical discharges lead to more rapid decomposition of the produced ozone.
Patent #5,008,087--April 16, 1991
Batchelor, Douglas R. Ozone Generator Apparatus and Method.
This patent outlines an ozone generating apparatus of the type involving concentric tube electrodes with a middle dielectric member. The device described in this patent consists of an inner electrode made of stainless steel which is hollow to effect more efficient cooling of the electrode, a middle dielectric member made of a glass material such as borosilicate, and an outer electrode made of stainless steel. The device is enclosed in a housing with a much larger diameter than the outer electrode so that a jacket through which water is introduced as a coolant can be inserted in the space. The chambers between the inner electrode and the dielectric member and the outer electrode and the dielectric member serve as gas discharge chambers so that applying a high voltage between the inner and outer electrodes produces a corona discharge of the gas through the dielectric member which creates ozone. One end of this device is sealed to enable feed gas traversing the gap between the inner electrode and dielectric member to reverse direction and traverse the gap between the dielectric member and the outer electrode thus producing additional ozone as the gas travels between the dielectric and the outer electrode. The created ozone is collected from an outlet when the gas returns to its starting point. The reversing of the gas flow cools the outer surface of the dielectric which reduces the difference in temperature between the inside and the outside of the dielectric; this reduction in temperature difference decreases stress on the dielectric and lengthens the life of the apparatus.
Patent #5,034,198--July 23, 1991
Kaiga, Nobuyoshi, et al. Ozone Generator and Ozone Generating Method.
This patent discusses an ozone generating device which consists of a dielectric tube with an inner-surface stainless steel coating between 2,000 A and 5,000 A thick. The stainless steel coating serves as the inner electrode in the water-cooled concentric tube electrode arrangement. The outer electrode is also made of stainless steel and serves as a grounding electrode. An oxygen-containing gas is fed into the device via a feed gas inlet, and the gas passes between the two electrodes which are connected to a high-frequency power source. The high-frequency power supplied to the stainless steel film by the source causes a silent discharge between the dielectric tube with the stainless steel coating and the outer cylindrical grounding electrode. The oxygen molecules in the gas are excited by the discharge to form ozone gas. The gas is then expelled from the chamber through a gas outlet. The inventors claim that the invention has the advantages of having an increased ozone generation amount per unit volume due to the high-frequency electric power supplied by the power source, high resistance of stainless steel against erosion by nitric acid which is formed when nitrogen oxides react with moisture in air and high resistance against erosion by ozone itself. The thickness of the stainless steel coating on the inside of the dielectric tube is ideal in that it is resistant to peeling due to repeated heating and cooling of the ozonizer.
Patent #5,093,087--March 3, 1992
Freeman, Michael D. Ozonator Apparatus.
This patent outlines an ozonator of the concentric tube electrode type. The ozonator comprises a conductive rod inside an outer metallic housing. The conductive rod is surrounded by a polymeric tube, and the ozonizing chamber is formed between this polymeric tube and a polymeric housing on the inside of the outer metallic housing. A twelve-volt coil with a positive terminal and a negative terminal and a coil output socket is in contact with the inner conductive rod. A battery with a positive and a negative twelve-volt cable is connected to the terminals of the twelve-volt coil, a source of 110 volt alternating current which is attached to a voltage regulator, and a capacitor bank are linked together to produce a discharge in the ozonizing chamber which excites oxygen to ozone. The device has the advantages of being compact, economical, and easy to use.
Patent #5,124,132--June 23, 1992
Francis, Jr., Ralph M., et al. Corona Discharge Ozone Generator.
This patent is for a tubular plasma discharge ozone generator. The ozonator described in this patent has a hollow metal cylinder in which a sealed glass tube is mounted so as not to touch the cylinder walls. The sealed glass tube is filled with an ionizable gas, and is connected to wire leads at both ends. Together, the outer metal cylinder and the sealed glass tube are designed to form the outer and inner electrodes for a discharge ozone generator. Oxygen containing gas is introduced into the apparatus between the outer and inner electrodes at one end of the tube and the ozone/oxygen containing gas is collected at the other end.
Patent #5,145,653--September 8, 1992
Fischer, Melchior, et al. Device for Generating Ozone.
This patent describes an ozone generator consisting of a plurality of concentric tube type ozone generators inside a casing. Each generator consists of an outer tubular metallic electrode inside which is a segmented inner electrode coated with a dielectric. The segments are supported and spaced independently from one another inside the outer electrode. A tension rod through the middle of the segmented inner electrode connects the segments and supplies power to the ozone generator. The segmenting of the electrode ensures accurate spacing between the electrodes because it eliminates the problems of dimensional deviation and bending.
Patent #5,268,151--December 7, 1993
Reed, Bruce A., et al. Apparatus and Method for Generating Ozone.
This patent details an ozone generator of the concentric tube electrode type. The inner electrode is a stainless steel tube which is surrounded by a glass dielectric tube separated from the stainless steel tube by non-conducting spacers forming a chamber for air to pass through. The glass tube is coated with a graphite dispersion in liquid which dries in a uniform, conductive layer. This outer coating of graphite serves as the outer electrode. Oxygen or an oxygen-bearing gas is introduced into the chamber between the inner electrode and the glass dielectric through holes in the upper portion of the inner stainless steel tube, and a corona discharge is formed in the gas by a pulsed electrical signal. The discharge splits apart O2 molecules to form oxygen atoms which may then recombine with O2 molecules to form O3. The ozone exits the generator through holes in the downstream end of the inner stainless steel tube.
Patent #5,411,713--May 2, 1995
Masao, Iwanaga. Ozone Generating Apparatus.
This patent is for a method of ozone production that uses discharge electrodes as the ozone generators. The outlined process uses a series of the ozone generators that are stacked on top of one another and are spaced in such a way so that the oxygen or oxygen-containing gas that enters into the ozone generating apparatus must pass successively through each individual generator. The individual generators themselves consist of a water cooled outer tubular electrode with a dielectric spacing and an inner linear electrode. Furthermore, the decreasing voltage differential occurs along the arrangement of electrodes in the direction of the gas flow.
