WO1999048807A1

WO1999048807A1 - Ozone generator and method of generating o¿3?

Info

Publication number: WO1999048807A1
Application number: PCT/US1999/006738
Authority: WO
Inventors: Wesley G. Price; Kenneth A. Wilson
Original assignee: Eden Air, Inc.
Priority date: 1998-03-26
Filing date: 1999-03-26
Publication date: 1999-09-30
Also published as: AU3211799A

Abstract

A device for generating ozone is provided. The device includes an ozone generating unit having a dielectric member having a first surface and a second surface, a high voltage electrode situated on the first surface of the dielectric member, and a ground electrode situated on the second surface of the dielectric member. The device also includes a chamber within which the ozone generating unit is situated so as to shield the ozone generated by the unit from oxidizing components of the ozone generator not within the chamber. A controller is provided for supplying a specific duration of power to the electrode so as to specifically control a concentration of ozone generated from the ozone generating unit.

Description

OZONE GENERATOR AND METHOD OF GENERATING O₃

Technical Field

This invention relates to devices and methods for generating an oxidant for treating pollutants or contaminants within an environment, and more particularly, to devices and methods for generating ozone gas.

Background Art

Ozone gas (O₃) is a triatomic form of oxygen (O₂). Ozone gas is typically oxygen that has been subject to high voltage. In converting oxygen to ozone, energy is absorbed resulting in an endothermic reaction. This absorption of energy results in an ozone gas that has a higher energy content than oxygen. As a result, ozone gas can be unstable and chemically very active in comparison to oxygen. Due to its unstable nature, ozone gas has been recognized as a strong oxidizing agent and has been used in various disinfecting applications. In particular, it is believed that ozone will oxidize pollutants or contaminants, such as smog, bacteria, mildew, mold, fimgi and other similar odor-causing or antigenic agents, in a particular environment, for instance, air or water, to render the pollutants or contaminants harmless and odorless, so as to disinfect and purify the environment.

Ozone can be generated by a variety of natural occurrences. For example, solar radiation can ionize oxygen in the atmosphere at high altitudes, in the arctic and over snow covered terrain so as to form ozone. Ozone may also be generated by electrical discharges from lightning.

There are also available various devices for generating ozone. These ozone generators typically include a pair of electrodes separated by a dielectric member and a space. The dielectric member and electrodes are often positioned within a housing adjacent to the transformer and other electrical components. When the transformer supplies a high voltage, an electrical discharge is generated forming an electrostatic field between the electrodes. In the presence of the electrical discharge, oxygen is converted into ozone. The ozone generated within the housing is then pulled from the housing by a fan into the environment. However, because the ozone is permitted to come into contact with the transformer, the fan, and other electrical components within the housing, these components tend to get oxidized by the ozone and may deteriorate, thus can shorten the period during which the ozone generator can be used.

Some ozone generators include electrodes and dielectric members that are tubular in construction. These tubular members are often constructed with fluctuation in the diameter along their lengths. The use of these tubular members, as a result, can lead to uneven spacing between the dielectric member and the electrodes. The uneven spacing can cause the generator to require more voltage than necessary, which can result in an inefficient generation ozone. In addition, many ozone generators are not designed to permit a precise control of the concentration of ozone to be generated. As a result, it may not possible to determine whether the amount of ozone generated from an ozone generator conform to, for example, EPA standards, which standards, for instance, provide for a safe outdoor air quality level of ozone at a concentration of about 120 parts per billion. Moreover, many ozone generators are big, bulky, and may not be portable. As a result, they may not permit the ozone generator to be easily moved to and from an area or environment which needs disinfecting and decontamination.

Accordingly, it is desirable to provide an ozone generator which permits efficient generation of ozone, while permitting for the precise control of a concentration of ozone to be generated. Furthermore it is desirable to provide an ozone generator which minimizes oxidation of the components in the generator and which is sufficiently portable for easy relocation from area to area.

Summary of the Invention In accordance with one embodiment of the present invention, an ozone generator is provided with an ozone generating unit. The ozone generating unit, in one embodiment, includes a high voltage electrode, a ground electrode, and a dielectric member positioned between and against the high voltage and ground electrodes. In the presence of, for example, electricity supplied to the electrodes, the ozone generating unit is designed to produce a high voltage electrical discharge to form an electrostatic field, which field is capable of converting oxygen into ozone. - 3 -

The ozone generating unit, in a preferred embodiment, is situated within a chamber, so as to isolate the unit from the other components of the ozone generator, for instance, a high voltage transformer used to provide the electrodes with electricity. This separation is important as it minimizes or prevents the generated ozone from oxidizing the components of the ozone generator, and causing these components to rust.

To maintain the ozone generating unit within the chamber, a connector is provided, in one embodiment, at an end of the chamber for removably securing the unit within the chamber. The connector can be provided with electrically conductive clamping members for transmitting electricity from the transformer to the electrodes. The conductive clamping members may also act to securely hold the ozone generating unit within the chamber.

A fluid impelling device, such as a fan, may also be provided at the end of the chamber adjacent the connector to facilitate fluid movement (e.g., air movement) into and out of the chamber. The position of the fluid impelling device can further minimize the occurrence of oxidation of the components of the ozone generator. Specifically, if the fluid impelling device were positioned at an end of the chamber opposite the connector, to remove the ozone from the chamber, the ozone must be pulled across the fluid impelling device and its components, thereby subjecting the device and its components to oxidation by the ozone. On the other hand, by positioning the fluid impelling device in the manner suggested by the present invention, the fluid impelling device can push the generated ozone out of the chamber, and not run the risk of being oxidized by the ozone as it moves across the fluid impelling device.

The ozone generator of the present invention also includes a controller for controlling the concentration of ozone to be generated by regulating the on/off cycles of the power transmitted to the ozone generating unit. This is accomplished by providing a switch circuit which can be actuated between an "on" position for permitting power to be supplied to the ozone generating unit and an "off position for preventing power to be supplied to the ozone generating unit. A microprocessor may also be provided for regulating the duration of the "on" period and the "off period to control the duration of power supplied to the ozone generating unit. Assuming that when continuous power is supplied to the ozone generating unit, full scale generation of ozone results. Thus, by controlling the duration of power supplied to the ozone generating unit, the user can precisely control the concentration of ozone generated as a percentage of full scale. The present invention, in accordance with one embodiment, also provides a method for generating ozone within a specified environment. Initially, a dielectric member is provided to aid in the generation of an electrical discharge. Thereafter, a high voltage electrode may be positioned adjacent one surface of the dielectric member. A ground electrode may be positioned adjacent another surface of the dielectric member, such that the electrodes are substantially opposite one another. Subsequently, the electrodes are caused to generate an electrical discharge, so as to form an electrostatic field for producing ozone in the presence of oxygen. Once the ozone has been produced, movement of the ozone into a desired environment is facilitated. In one embodiment, the ozone generated may be confined to a specific area prior to being directed to the desired environment.

Brief Description of the Drawings

Fig. 1 illustrates an ozone generator in accordance with one embodiment of the present invention.

Figs. 2 A-C illustrate a longitudinal and end views of an ozone generating chamber for used in the ozone generator shown in Fig. 1. Fig. 3 is a top sectional view of the ozone generating chamber shown in Fig. 2.

Fig. 4 is a block diagram of a controller in accordance with an embodiment of the present invention.

Fig. 5 is a schematic diagram of a switch circuit for use in connection with the controller shown in Fig. 4. Fig. 6 is a schematic diagram of a detector unit and microprocessor for use in connection with the controller shown in Fig. 4.

Fig. 7 is a block diagram of a controller and ozone generator in accordance with one embodiment of the present invention.

Fig. 8 illustrate a control panel for use in connection with an ozone generator of the present invention.

Figs. 9A-D illustrate a set of waveforms for a resistive load. Figs. 10A-D illustrate a set of waveforms for an inductive load. - 5 -

Figs. 11 A-D illustrate a set of waveforms for a capacitive load.

Detailed Description of Specific Embodiments With reference now to embodiments of the present invention, Fig. 1 illustrates an ozone generator 10 having a housing 12, within which an ozone generating chamber 14 is positioned. The housing 12 includes a fluid input 121 and a fluid output 122. In the embodiment shown in Fig. 1, each of the input 121 and output 122 is situated at one end of the housing 12 substantially opposite one another, with the ozone generating chamber 14 extending between the input 121 and output 122. The input 121 permits fluid, such as air, from the environment to flow into the housing 12, through the ozone generating chamber 14, and out through the output 122. This alignment of the chamber 14 with the input 121 and output 122 permits efficient fluid flow into the chamber 14 and ozone flow out of the chamber 14. Of course other alignment designs may also be used so long as efficient fluid flow is maintained. For instance, the input 121 and output 122 may be situated diagonally from or substantially at right angle to one another.

To further facilitate efficient movement of fluid into and out of the housing 12, the generator 10 is provided with a fluid impelling device 16. In an embodiment of the invention, the fluid impelling device 16 can either be an axial or a centrifugal fan that is situated between the fluid input 121 of the housing 12 and an input end 141 of the chamber 14. By positioning the fluid impelling device 16 adjacent to the input end 141, the amount of oxidation which may occur within the generator 10 may be minimized. If the fluid impelling device 16 is positioned at an end of the chamber 14 opposite the input end 141, the motor and blades (not shown) on the fluid impelling device 16 can act as potential oxidizing surfaces across which generated ozone within the chamber 14 must move. If oxidized, the motor and blades may quickly rust, thereby shortening the period over which the generator 10 may be useful. If on the other hand, the fluid impelling device is positioned in the manner shown in Fig. 1, fluid from the environment may initially be pulled into the chamber 14 through the input 121, but is subsequently pushed out of the chamber 14 through the output 122. As a result, the path over which the ozone must move from inside the chamber 14 to the environment completely avoids movement across the fluid impelling device and its motor. - 6 -

In addition, a filter 18 may be situated adjacent the fluid impelling device 16 to remove particulates which may interfere with the generation of ozone, and to provide the generator 10 with substantially clean fluid from which ozone may be generated. In one embodiment of the invention, the filter 18 may be positioned between the fluid input 121 of the housing 12 and the fluid impelling device 16. Alternatively, the filter 18 may be positioned between the fluid impelling device 16 and the input end 141 of the chamber 14. It should be noted, however, that regardless of its position, the filter 18 is preferably designed for easy removable to permit cleaning of the filter should the filter 18 become full of particulates. Referring now to Figs. 2A-C, there is shown the ozone generating chamber 14 in accordance with one embodiment of the present invention. The chamber 14 includes an ozone generating unit 20 situated horizontally along the length of the chamber 14. The generating unit 20, as illustrated in Fig. 2 A, includes a dielectric member 21 positioned between a pair of electrodes 22 and 24. The electrodes preferably includes a high voltage electrode 22 and a ground electrode 24. In the presence of power (i.e., electricity) supplied to the high voltage electrode 22 and ground electrode 24, a high voltage electrical discharge may be generated to form an electrostatic field between the electrodes 22 and 24. During the presence of the electrostatic field, if oxygen is present within the electrostatic field, the oxygen can be converted into ozone. It should be noted that power may be supplied to the electrodes 22 and 24 by a transformer 25 (Fig. 1) having an electrical conduit (not shown) for connection to a power source. In one embodiment, the transformer may be positioned within the housing 12 but external of the chamber 14.

The dielectric member 21, as shown in Fig. 2 A, may be defined by a substantially thin and flat rectangular plate. In a preferred embodiment, the dielectric member 21 may be provided with a width which substantially spans the interior of the chamber 14 and a thickness of approximately 0.025 in. The dielectric member 21 may be manufactured from a high density tape cast material having approximately 96%, by weight, aluminum oxide. Such a material may be obtained commercially as Lasered Substrate R708S from CeramTec in Mansfield, Massachusetts. The electrodes 22 and 24 may similarly be substantially thin, flat and rectangular in shape. The electrodes 22 and 24, however, are provided with an area that is measurably smaller than that provided to the dielectric member 21 (see Fig. 3). In a preferred embodiment, the electrodes 22 and 24 may be - 7 -

manufactured from, for example, #304 stainless steel wire mesh, such as WC 10 X 10 mesh, with a perforated diameter of about 0.028 in. Such mesh can be obtained commercially from Belleville Wire Cloth Co., Inc. in Cedar Grove, New Jersey. Although the electrodes 22 and 24 and the dielectric member 21 are shown to be rectangular in shape, it should be appreciated that the electrodes and the dielectric member may be provided with any geometric shape, so long as the shape permit efficient generation of ozone.

The ozone generating unit 20, as indicated, may be situated horizontally along the length of the chamber 14. To support the unit 20 in the horizontal position within the chamber 14, mounting channels 26 (Fig. 2B) may be provided along opposite sides of the chamber 14. The mounting channels 26 should be designed with a sufficient width to permit the dielectric member 21 to securely fit therein. Preferably, however, the ozone generating unit 20 may be situated diagonally along the length of the chamber 14, as illustrated in Fig. 2C. By positioning the unit 20 diagonally, the area over which ozone may be generated can be increased up to about 140% over an ozone generating unit 20 mounted horizontally in the same chamber 14.

It should be appreciated that there are several advantages in using the ozone generating chamber 14. One advantage is to permit isolation of the generated ozone from, for instance, the electrical components of the ozone generator 10, such as, a high voltage transformer used to provide the electrodes 22 and 24 with electricity, to minimize and prevent oxidation of those components. Another advantage is permit efficient direction of generated ozone into the environment. In particular, by limiting the generated ozone within the confined area of chamber 14, the generated ozone can be easily pushed along the chamber 14 and out through the output 122. Since the chamber 14 will be exposed to the oxidative nature of ozone over an extended period of time, it is preferable that the chamber 14 be constructed from a material resistant to oxidation by ozone. One example of an oxidation resistant material is polystyrene. Other oxidative resistant material known in the art may also be used. The chamber 14, in a preferred embodiment, is rectangular in shape and is an integrally extruded member, that is, it can be extruded as one piece. In the alternative, the chamber 14 can be manufactured with multiple pieces for subsequent assembly. - 8 -

Referring now to Fig. 3, there is shown a connector 30 for removably securing the ozone generating unit 20 within the chamber 14. The connector 30, positioned adjacent the input end of the chamber 14, can also act as a stop for the ozone generating unit 20 as the unit 20 is inserted into the chamber 14. The connector 30 includes a board 32, which substantially spans the interior width of the chamber 14 similar in manner to the dielectric member 21, and which securely fits within the mounting channel 26. If desired, the board 32 may be secured within the chamber 14 by any attachment means known in the art, for example, adhesives or screws. By securing the board 32 within the chamber 14, high voltage leads 34 from a transformer may be fixed on the board 32 for subsequent coupling to the electrodes 22 and 24.

The connector 30 further includes clamping members 36 for firmly engaging and removably securing the ozone generating unit 20 between the members 36. As shown in Figs. 2A-C, each of the clamping members 36 can be fixedly positioned on one side of the board 32 to permit a sliding engagement of the ozone generating unit 20 between the clamping members 36. Furthermore, the positions of the clamping members 36 are such that clamping members 36 can provide the ozone generating unit 20 with a firm and secure grip. For example, the clamping members 36 may be positioned away from the center of the board 32 and towards the sides of the chamber 14. Alternatively, the clamping members 36 may be provided with a substantially wide width, such that a larger surface area of the unit 20 may be engaged. In one embodiment of the invention, the clamping members 36 are designed to contact the electrodes 22 and 24 and to couple the high voltage leads 35 from the transformer to the electrodes, so that power may be transmitted to the electrodes for the generation of an electrical discharge. Accordingly, the clamping members 36 are preferably constructed from an electrically conductive material, such as stainless steel. The use of stainless steel also prevents oxidation of the clamping members 36 by the ozone. The board 32, on the other hand, is preferably constructed from or includes an insulative material to prevent any potential electrical shortage to the ozone generating unit 20.

The production of ozone by the generator 10 can be precisely controlled by using a alternating current (AC) controller 40, illustrated as part of a system shown in Fig. 4. The AC controller 40, in accordance with one embodiment of the present invention, includes a switch circuit 42, a detector circuit 43, a microprocessor 44 and a data input circuit 45. It - 9 -

should be understood that the term AC refers to a typical AC input line voltage of 115 volts, at a frequency of 60 cycles per second (Hertz), common in use as a household utility current in the United States. However, it should be understood that AC controller application is not restricted to this voltage or frequency. As shown in Fig. 7, the AC controller 40 may be used in combination with an ac load 41, such as an ozone generator 10 described above. Although the discussion hereinafter will be in connection with an ozone generator 10, it will be appreciated that the AC controller 40 of the present invention may be used to control a variety of different ac load with any particular function. Moreover, reference to either "ac load" or "ozone generator" hereinafter should be understood as reference to the same component. The switch circuit 42 of the AC controller 40, in one embodiment, may be interposed between the ozone generator 41 and the ac voltage return 48. The switch circuit 42 is designed to control the supply of power to the ozone generator 41 by actuating between an "on" position and an "off position. In the "on" position, the ozone generator 41 is connected to ac input line 47 to permit power to be supplied to the ozone generating unit 20. In the "off position, the ozone generator 41 is disconnected from the ac input line 47 to prevent power from being supplied to te ozone generating unit 20. The ac input line 47 and the ac voltage return 48 together comprise a power input to the system from a power source. The microprocessor 44 of the AC controller 40 can be coupled to the switch circuit

42 to regulate the actuation of the switch circuit 42. To regulate the actuation of the switch circuit 42, the microprocessor 44 provides an output signal sw-sig 46 to the switch circuit 42, which output signal sw-sig 46 actuates the switch circuit 42 between the on and off positions. Looking now at Fig. 5, in accordance with one embodiment of the invention, when the output signal 46 is sent from the microprocessor 44 is relatively high, transistor 50 is turned on, causing collector 51 to be pulled towards ground and allowing triac gate 56 to conduct. This switches on triac 58 to permit the ozone generator 10 to be connected across the ac voltage input 47 and ac voltage return 48. When the output signal 46 sent from the microprocessor 44 is relatively low, the transistor 50 is turned off, thus not allowing current to be conducted through resistor 59. As a result, collector 51 is caused to rise to +12V to inhibit triac gate 56 from conducting, which in turns inhibits the triac 58 from connecting the ozone generator 10 across the ac voltage input 47 and ac - 10 -

voltage return 48. Capacitor 570 and resistor 571 are provided in series across triac 58 and to create a path for absorbing transient energy during switching.

The generation of output signal 46 takes into consideration, in part, the data received from the detector circuit 43. The detector circuit 43, referring now to Fig. 6, is connected to the ac input line 47 and the microprocessor 44, and is designed to receive voltage input from the input line 47. When the detector circuit 43 receives a voltage input from the input line 47, the detector circuit 43 provides a detector signal, sense-sig 49, to the microprocessor 44, which detector signal 49 can indicate to the microprocessor 44 the input voltage level. The detector circuit 43, in an embodiment, includes resistor 62 and diodes 63 and 64. Diode 63 can be provided between resistor 62 and microprocessor 44 to limit the maximum voltage applied to the microprocessor 44. In one embodiment of the invention, the maximum voltage applied to the microprocessor 44 is limited to about 5.5 V. Diode 64, on the other hand, can be provided between resistor 62 and microprocessor 44 to limit the minimum voltage applied to the microprocessor 44. In one embodiment of the invention, the minimum voltage applied to the microprocessor 44 is limited to about -0.5 V. The resistor 62 for use with the present invention may be a 1 mega ohm resistor.

The generation of output signal 46 to the switch circuit 42 also results in part from data received from the data input circuit 45. The data input circuit 45, in one embodiment, is connected to the microprocessor 44 and provides the microprocessor with input information from, for example, a user, regarding how the ozone generator 41 is to operate. By way of example, the data input circuit 45 may include a set of controls (see Fig. 8) provided, for instance, on the ozone generator 10 for setting a desired concentration of ozone to be produced. The data input circuit 45 may also be in a remote format, such as an RS-232 format, similarly used to regulate the concentration of ozone to be produced.

The microprocessor 44 may additionally include stored application-specific data and algorithms which will, in combination with data from the data input circuit 45 and signals from the detector circuit 43, regulate the actuation pattern of the switch circuit 42, so as to precisely control the concentration of ozone to be produced by the ozone generator 10. - 11 -

The function of the controller is described hereinafter in accordance with one embodiment of the present invention. A user may initially access the data input circuit 45 by way of control panel 80, shown in Fig. 8. The control panel 80 can be provided on the front of the ozone generator housing 12. The user may operate the "ozone level" control 81 to precisely set the concentration level of ozone to be produced. One hundred percent (100%) on the "ozone level" control represents full scale generation of ozone. Full scale generation, in one embodiment, is dependent on certain factors, including the size of the ozone generating unit 20. Thus, if the concentration of ozone produced at full scale is determined to be, for example, 100 parts per billion (i.e., 0J0 ppm), the "ozone level" control 81 will permit the user to precisely set the concentration of ozone to be produced as a percentage of full scale. The "fan" control 82 permits the user to set the speed of the fluid impelling device 16, and thus the force with which the generated ozone is pushed from the chamber 14. The "time" control 83 permits the user to set the time duration for which the ozone generator operates. The control panel 80 may also have an "ozone level" setting for specific concentrations, so that a user may avoid calculating the concentrations as a percentage of full scale.

It should be noted that the acceptance of ozone as a disinfectant is well established worldwide, but is still being considered in the United States. Studies have shown that, when continuously exposed to the presence of ozone, the human irritation threshold is about 0.06 parts per million (ppm) with no evidence of health damage. Moreover, it has been well established that ozone will oxidize odors and other indoor pollutants at a concentration that is about one-eighth of the limit established by the American Conference of Governmental Industrial Hygienists. Once the odors and pollutants have been oxidize, the residual ozone in the environment will decay to oxygen. This decay rate is a function of temperature, that is, the warmer the temperature of the environment, the faster the rate of decay, and the cooler the temperature of the environment, the slower the rate of decay.

In the United States, several different organizations have established ozone concentration limits which are deemed acceptable for human exposure, depending on the environment. Below is a representative list: - 12

Concentration (ppm) Environment

0J 2 Environmental Protection Agency (EPA) limit for city, outdoor, and air quality

0J 0 American Conference of Governmental

Industrial Hygienists limit for exposure for eight-hour day with no observed side effects 0.05 Food and Drug Administration (FDA) limit for ozone generator labeled as medical device

0.05 Underwriters Laboratory (UL) limit for ozone produced by electrostatic precipitators

0.03-0.06 Typical measurement in cities

0.01-0.015 Odor threshold for most people

0.005-0.1 Typical measurement in fresh country air

In operation, referring to Figs. 4-8, the ozone generator 10 is turned on when AC power is applied between input line 47 and voltage return 48 (Fig. 4), as represented by, for example, the sinusoidal waveform in Figs. 9 A, 10A and 11 A. In one embodiment, +5V power, a typical power level from the standard power supply, is used by the microprocessor 44 and the detector circuit 43. When the microprocessor 44 initially receives this +5V signal, it is prompted to initialize its programs and to send an output signal, sw-sig 46, at 0V (i.e., 5V common) to the switch circuit 42 to disconnect the ozone generator 10 from the ac voltage input 47. Thereafter and once data input has been established by the user by way of control panel 80, the AC controller 40 can act to precisely generate the desired concentration of ozone set by the user. In particular, at the instant of data input from the control panel 80, the microprocessor 44 begins monitoring for a detector signal, sense-sig 49 (representative of the square wave form in Fig. 9B) from the detector circuit 43, which signal is indicative of the input voltage received by the detector circuit 43 from the ac input line 22. At the instant the detector signal 49 from the detector circuit 43 changes from low (from about 0V to about 1.5V) to high - 13 -

(from about 3V to about 5V), the microprocessor 44 sends an output signal 46 to the switch circuit 42 to connect the ozone generator 10 to the ac voltage input 47. The microprocessor 44 then, while monitoring the detector signal 49 from the detector circuit 43 so as to determine the state of the AC input voltage, counts for the positive transitions 901 in the detector signal 49.

The microprocessor 44, depending on the concentration level set by the user as a percentage of full scale and provided to the data input circuit 45, will determine the pattern for regulating the on off actuation of the switch circuit 42, based on a particular algorithm stored in the microprocessor 44. In accordance with one embodiment, the concentration of ozone produced by the ozone generator 10 is related to the duration of power applied to the ozone generator 10. That is, if the power is supplied continuously to the ozone generator, continuous full scale ozone generation is provided. The present invention, in applying this concept, has discovered that by regulating the duration of power applied to the ozone generator 10, the concentration of ozone as a percentage of full scale can be precisely set for generation.

By way of example, if the "ozone level" control 81 is set for 50% of full scale, the microprocessor 44 is designed to count, for example, six positive transitions 901 during which power is supplied to the ozone generator 10, then sends an output signal 46 to turn off the switch circuit 42 to disconnect the supply of power to the ozone generator 10. The microprocessor 44 then continues to count the positive transitions 901, and when the sixth positive transitions 901 is again counted after the previously sent output signal 46, another output signal 46 is sent to turn the switch circuit 42 on. In other words, if the "ozone level" control 81 is set to 50%, the switch circuit 42 would be regulated by the microprocessor 44 to actuate to the "on" position for about 6 cycles along the sinusoidal wave form in Fig. 9A and then actuated to the "off position for about 6 cycles. This pattern of on/off actuation would last for the duration of the period set by the "time" control 83 or until the user provides a new set of data input to the data input circuit 45. The duration of power can be represented by the following formula:

Duration of power = (n(on)/[n(on) + n(off)]) X 100 - 14 -

where n is representative of the number of cycles along a 60 cycles per second sinusoidal waveform in Fig. 9A or positive transitions along a square waveform in Fig. 9B. Applying this formula to the above example, the following is obtained:

50% = 6 cycles on/ (6 cycles on + 6 cycles off) X 100

Accordingly, if it is known that with continuous power to the ozone generator results in continuous full scale ozone generation, then if the duration of power to the ozone generator is only 50% of the time, only 50% of the full scale concentration of ozone would be produced. Thus, if the full scale production of ozone by the ozone generating unit 20 is 0J0 ppm, then a setting of 50% will be 0.05 ppm.

If, on the other hand, the "ozone level" control 81 is set to 1%, the switch circuit 42 would by regulated by the microprocessor 44 to actuate to the "on" position for about 6 cycles, and then actuated to the "off position for about 594 cycles. Using the formula above, the duration of power supplied to the ozone generating unit 10 would be:

6 cycles on/(6 cycles on + 594 cycles off) X 100 = 1%

Accordingly, if full scale production is 0J0 ppm, then 1% will only be 0.001 ppm. Of course, the ozone generating unit may be designed to have a full scale production of ozone at any desired concentration.

To further precisely control the concentration of generated ozone as a percentage of full scale, the microprocessor 44, in accordance with an embodiment of the invention, can be designed to actuate the switch circuit 42 between the "on" and "off positions at substantially the same point of a cycle along a waveform analyzed. The following is an illustration of the switching of various types of devices using the AC controller 40.

Figs. 9A-D show the waveforms for the switching of a device that is a resistive load type using the AC controller 40 at 50% of full power. The switching of the switch circuit 42, for exemplary purposes only, uses a three cycle duration, that is, 3 "on" cycles and 3 "off cycles of ac power across the device. Each cycle is represented by one positive transition 901 and one negative transition 902. Fig. 9A is the waveform of the ac input voltage 22. Fig. 9B is the waveform of the detector signal 49 from the detector - 15 -

circuit 43. Fig. 9C is the waveform of the switch-sig output signal 46. As indicated above, when the switch-sig 46 is hi (item 99), the switch circuit 42 is actuated to the "on" position to permit the ac input voltage 22 to be applied across the device, as shown in Fig. 9D. When the switch-sig 46 is low (item 98), the switch circuit 42 is actuated to the "off position to prevent the ac input voltage 22 from being applied across the device, as shown in Fig 9D. In a device that is of the resistive load type, the ac voltage across the device is in phase with the ac current through the device, and any transients caused by switching are thus minimized.

Figs. 10A-D show the waveforms for the switching of a device that is an inductive load type using the AC controller 40 at 50% of full power. The switching of the switch circuit 42 is shown using a three cycle duration. Fig. 10A is the waveform of the ac input voltage 22. Fig. 10B is the waveform of the detector signal 49 from the detector circuit 43. Fig. IOC is the waveform of the switch-sig 46. As indicated above, when the switch- sig 46 is hi (item 102), the switch circuit 42 is actuated to the "on" position to permit the ac input voltage 22 to be applied across the device, as shown in Fig. 10D. When the switch-sig 46 is low (item 101), the switch circuit 42 is actuated to the "off position to prevent the ac input voltage 22 from being applied across the device, as shown in Fig 10D. In a device that is of the inductive load type, the ac voltage across the device is leading the ac current through the device. It should be noted that a negative transition 104 of the switch-sig 46 has been advanced by an amount of time 103 sufficient to cause the voltage across the device to be disconnected at exactly the time when the ac current through the device is passing through zero. This disconnection at the instant of zero load current minimizes any transients caused by load switching.

Figs. 11 A-D show the waveforms for the switching of a device that is a capacity load type using the AC controller 40 at 50% of full power. The switching of the switch circuit 42 is shown using a three cycle duration. Fig. 11 A is the waveform of the ac input voltage 22. Fig. 1 IB is the waveform of the detector signal 49 from the detector circuit 43. Fig. 11C is the waveform of the switch-sig 46. When the switch-sig 46 is hi (item 115), the switch circuit 42 is actuated to the "on" position to permit the ac input voltage 22 to be applied across the device, as shown in Fig. 1 ID. When the switch-sig 46 is low (item 114), the switch circuit 42 is actuated to the "off position to prevent the ac input voltage 22 from being applied across the device, as shown in Fig 1 ID. In a device that is - 16 -

of the capacitive load type, the ac voltage across the device is lagging the ac current through the device. It should be noted that the negative transition 113 of the switch-sig 46 has been delayed by an amount of time 116 sufficient to cause the voltage across the device to be disconnected at exactly the time when the ac current through the device is passing through zero. This disconnection at the instant of zero load current minimizes any transients caused by load switching. In order to delay the timing of the negative transition 113 of the switch-sig 46, the microprocessor 4 detects the negative transition 113 of the n-l(off)'th cycle of the ac power and adds a delay time equal to the time for one cycle 117 minus the required delay time 116. While the invention has been described in connection with the specific embodiments thereof, it will be understood that it is capable of further modification. For example, the ozone generator 10 may be modified for use in the generation of ozone in water. The ozone generator may also be provided with a sensor which detects a concentration of ozone in an environment, which sensor can instruct the generator to stop generating ozone above a certain concentration. Furthermore, this application is intended to cover any variations, uses, or adaptations of the invention, including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as fall within the scope of the appended claims.

Claims

- 17 -What is claimed is:

1. An ozone generator comprising:

(a) an ozone generating unit including a dielectric member having a first surface and a second surface; a high voltage electrode situated on the first surface of the dielectric member; and a ground electrode situated on the second surface of the dielectric member; wherein an electrical discharge from the first and second electrodes causes generation of an electrostatic field, which field being capable of generating ozone in the presence of oxygen;

(b) a chamber within which the ozone generating unit is situated so as to shield the ozone generated by the unit from oxidizing components of the ozone generator not within the chamber; and (c) a controller for supplying a specific duration of power to the electrode so as to specifically control a concentration of ozone generated from the ozone generating unit.

2. An ozone generator as set forth in claim 1 further including a connector attached to the chamber for removably securing the ozone generating unit within the chamber.

3. An ozone generator as set forth in claim 1, wherein the connector includes electrically conductive members for contacting the electrodes.

4. An ozone generator as set forth in claim 1, wherein the chamber is an integrally extruded member.

5. An ozone generator as set forth in claim 1, wherein the chamber is constructed from a material resistant to oxidation by the ozone. - 18 -

6. An ozone generator as set forth in claim 5, wherein the material is polystyrene.

7. An ozone generator as set forth in claim 1 , wherein the dielectric member comprises a ceramic material.

8. An ozone generator as set forth in claim 7, wherein the ceramic material includes aluminum oxide.

9. An ozone generator as set forth in claim 7, wherein the ceramic material is approximately 96% by weight aluminum oxide.

10. An ozone generator as set forth in claim 1, wherein each of the electrodes comprises an electrically conductive wire mesh.

11. An ozone generator as set forth in claim 10, wherein the conductive wire mesh is stainless steel.

12. An ozone generator as set forth in claim 1, wherein the controller includes a switch circuit which can be actuated between an on position for permitting power to be supplied to the ozone generating unit and an off position for preventing power to be supplied to the ozone generating unit.

13. An ozone generator as set forth in claim 12, wherein the controller further includes a microprocessor for regulating an on/off cycle of the switch circuit so as to control the duration of power to the ozone generating unit.

14. An ozone generator as set forth in claim 13, wherein the duration of power to the ozone generating unit correspond to a ratio between a total of on cycles and a total of on and off cycles over a period during which the controller is operating, which ratio is determinative of a calculable concentration of ozone produced by the ozone generating unit. - 19 -

15. An ozone generator as set forth in claim 1 further comprising a fluid impelling device located at one end of the chamber to facilitate fluid movement into the chamber, which fluid movement subsequently pushes generated ozone out from the chamber.

16. An ozone generator as set forth in claim 15, wherein the one end of the chamber permits fluid input into the chamber by the fluid impelling device.

17. An ozone generator as set forth in claim 16 further including a fluid filter positioned against a surface of the fluid impelling device opposite a surface of the impelling device that is adjacent the chamber.

18. An ozone generator as set forth in claim 16 further including a fluid filter positioned between the chamber and the fluid impelling device.

19. An ozone generator as set forth in claim 1, wherein the ozone generating unit is positioned within the chamber along the length of the chamber.

20. An ozone generator as set forth in claim 1, wherein the ozone generating unit is positioned within the chamber substantially diagonally along the chamber.

21. An ozone generator comprising: an ozone generating chamber; a dielectric member situated within the chamber; a high voltage electrode positioned against a surface of the dielectric member, which electrode when supplied with power is capable of generating an electrical discharge to form an electrostatic field for generating ozone in the presence oxygen; a controller for regulating a specific duration of power to the electrode, so as to specifically control a concentration of ozone generated; and a fluid impelling device positioned at one end of the chamber to facilitate fluid movement into the chamber and ozone movement from the chamber. - 20 -

22. An ozone generator as set forth in claim 21 further including a ground electrode positioned against the dielectric member.

23. An ozone generator as set forth in claim 21, wherein the ozone generating chamber acts to confine generated ozone within the chamber, so as to isolate such ozone from coming into contact with and oxidizing components of the ozone generator.

24. An ozone generator as set forth in claim 21, wherein the position of the fluid impelling device at one end of the chamber facilitate movement of fluid into the one end of the chamber and ozone movement out of an opposite end of the chamber, so as not to permit ozone movement over the impelling device.

25. An ozone generator as set forth in claim 21 , wherein the dielectric member is positioned substantially diagonally along the chamber.

26. A method of generating ozone within a specified environment comprising: providing a dielectric member; positioning a high voltage electrode adjacent one surface of the dielectric member; causing the electrode to generate an electrical discharge to form an electrostatic field for formation of ozone in the presence of oxygen; defining a pattern of electrical discharge, so as to precisely control a concentration of ozone generated within the environment; and facilitating movement of the generated ozone into the specified environment.

27. A method as set forth in claim 26 further including positioning a ground electrode adjacent an opposite surface of the dielectric member.

28. A method as set forth in claim 26 further including the step of confining the ozone generated to a particular area prior to facilitating movement of the generated ozone into the specified environment. - 21 -

29. A method as set forth in claim 26, wherein in the step of defining, the control of the concentration of ozone generated includes regulating an on/off pattern of power directed to the electrode.

30. A method as set forth in claim 29, wherein the concentration of ozone generated is in a sufficient amount to permit oxidation of targeted pollutants without causing irritation to a human being.

31. A controller for regulating the power applied to an electrical device, the controller comprising: a switch circuit for controlling a supply of power to the device by actuating between an "on" position and an "off position; and a microprocessor for regulating the actuation of the switch circuit in accordance with a predetermined pattern, so as to control a duration over which the switch circuit is in "on" position and a duration over which the switch circuit is in the "off duration; wherein the power applied to the device is a ratio between duration of the "on" position and a total duration of the "on" position and the "off duration.

32. A controller as set forth in claim 31 further including a detector circuit for providing a signal to the microprocessor, which signal permits the microprocessor to calculate the duration over which the switch circuit is to remain in the "on" position and the duration over which the switch circuit is to remain in the "off position.

33. A controller as set forth in claim 31 further including a data input circuit to permit an input of conditions for influencing the regulation of the actuation pattern of the switch circuit.

34. A controller as set forth in claim 31 , wherein the power is an alternating current having a regularly repeating waveform.

35. A controller as set forth in claim 34, wherein the microprocessor actuates the switch circuit to an "on" position at substantially a same point along the waveform. - 22 -

36. A controller as set forth in claim 34, wherein the microprocessor actuates the switch circuit to an "off position at substantially a same point along the waveform, the point along the waveform when the switch circuit is actuated to the "off position being different than the point along the waveform when the switch circuit is actuated to the "on" position.

37. A controller as set forth in claim 31 , wherein the device is an ozone generator having an ozone generating chamber, a dielectric member situated within the chamber, a high voltage electrode positioned against a surface of the dielectric member, which electrode when supplied with power is capable of generating an electrical discharge to form an electrostatic field for generating ozone in the presence oxygen, and a fluid impelling device positioned at one end of the chamber to facilitate fluid movement into the chamber and ozone movement out from the chamber.

38. A method for regulating power applied to an electrical device, the method comprising: controlling a supply of power to the device by switching between an "on" position and an "off position; and regulating the switching in accordance with a predetermined pattern, so as to control a duration of the "on" position and a duration of the "off duration; the power applied to the device being a ratio between the duration of the "on" position and a total duration of the "on" position and the "off duration.