Patent Publication Number: US-7224567-B2

Title: Structural arrangements for ion generator to promote ionization efficiency

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a division of application Ser. No. 09/979,081, filed Nov. 16, 2001, now U.S. Pat. No. 6,769,420 which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an ion generator adapted to generate ozone by ionizing air introduced into a casing. 
     DESCRIPTION OF THE PRIOR ART 
     There have been used ion generators designed to supply ionized air to intake manifolds of internal combustion engines for the purposes of enhancing the combustion efficiency thereof, improving the fuel economy and reducing the air pollution. 
       FIG. 10  is a sectional view showing an exemplary prior-art ion generator. A casing  80  of this ion generator includes a cylinder body  89  which is formed from stainless steel or the like and the opposite ends of which are closed by caps  84 ,  85 . One  84  of the caps is formed with an intake port  86  whereas the other cap  85  is formed with an exhaust port  87 . The ion generator has an arrangement wherein a gap between the intake port  86  and the exhaust port  87  defines an air-flow passage A in which a high-voltage generator  88  is disposed on an upstream side and an ionization electrode I is disposed on a downstream side. 
     The ionization electrode I includes an outside electrode  81  formed by a part of the cylinder body  89 , an inside electrode  82  disposed centrally of the outside electrode  81 , and a pair of disk-like support members  83  for supporting the inside electrode  82 . The inside electrode  82  includes a conductive shaft  82   a  bridging the pair of support members  83 , and a plurality of star electrodes  82   b  axially mounted on the conductive shaft  82   a  at regular space intervals. The inside electrode  82  is connected to one pole of the high-voltage generator  88  while the outside electrode  81  is connected to the other pole of the high-voltage electrode  88 . 
     The pair of support members  83  are formed from an insulating material. The support members are each formed with vent holes  83   c  extended through a side thereof and arranged at given space intervals along a circumference about the shaft  82   a  such that the air introduced into the casing  80  through the intake port  86  is guided to the exhaust port  87  by the vent holes. 
     In the ion generator, a high voltage is applied between the outside electrode  81  and the inside electrode  82  of the ionization electrode I for effecting corona discharge there between such that the air in the electrode is ionized to produce ozone. 
     Unfortunately, the ionization electrode I of  FIG. 10  suffers a poor air-ionization efficiency because a majority of the corona discharge develops from the star electrodes  82   b  at the opposite ends of the shaft  82   a  while the other star electrodes  82   b  between these electrodes do not function effectively. The ionization electrode also suffers the following problem. If the star electrodes are eccentric with respect to the outside electrode  81  due to the working errors or mounting errors of the outside electrode  81  and the inside electrode  82 , the corona discharge will concentrate on some of the pointed ends of the star electrodes  82   b  that are the closest to the outside electrode  81 , thus developing into spark discharge, which will cause burn of an electric circuit component and the like of the high-voltage generator  88 . Furthermore, even if the discharge does not concentrate on one place, there occurs an instable corona discharge rather closer to the spark discharge. Hence, a measure must be taken to provide the stable discharge by increasing the current value of a primary winding of a transformer incorporated in the high-voltage generator  88 . This results in an increased power consumption. 
       FIG. 11  is a sectional view showing an ionization electrode D of another prior-art ion generator. 
     A casing  90  of the ionization electrode D includes a cylinder body  91  formed from a resin material and a pair of closure plates  92  for closing opposite ends of the cylinder body  91 , the closure plate formed with a plurality of vent holes  92   a.    
     The ionization electrode D includes a hollow brass electrode  93  attached to one of the closure plates  92  of the casing  90 , and a spherical electrode portion  94  attached to the other closure plate  92 . The spherical electrode portion  94  consists of a spherical electrode  94   a  and a support member  94   b . A plurality of rectangular fins  93   a  formed from a thin stainless-steel sheet are attached to an outer periphery of a distal end of the hollow electrode  93 , the fins arranged with equal spacing. 
     The ionization electrode D operates as follows. A DC positive high voltage is applied between the hollow electrode  93  and the spherical electrode portion  94  while allowing for an air flow from the hollow electrode  93  to the spherical electrode portion  94 , thereby effecting corona discharge B from end faces of the fins  93   a  toward the spherical electrode  94   a , the end faces opposing the spherical electrode portion  94 . The air within the electrode D is ionized by the corona discharge B to produce ozone. 
     The ionization electrode D of  FIG. 11  involves a cumbersome working of the fins  93   a , which are insufficient in the ability to generate discharge unless they are so thin as about 0.1 mm. In addition, this electrode also suffers the same drawbacks as the ionization electrode I of  FIG. 10 . That is, the discharge concentrates on one place due to the working errors or mounting errors of the electrodes, resulting in the burn of the electric circuit component and the like. Even if the discharge does not concentrate on one place, the current value of the primary winding of the transformer must be increased and hence, an increased power consumption results. 
     Accordingly, it is an object of the invention to provide an ion generator adapted for stable generation of corona discharge despite the working errors or mounting errors of the electrodes. 
     It is another object of the invention to provide an ion generator allowing for the reduction of the current value of the primary winding of the transformer thereby achieving the reduction of power consumption. 
     It is still another object of the invention to provide an ion generator adapted to improve the air ionization efficiency. 
     DISCLOSURE OF THE INVENTION 
     One structural arrangement for an ion generator according to the inventions described herein includes a casing having an intake port and an exhaust port; an ionization electrode contained in the casing and including a first plate-like pole having a plurality of pointed ends at least on a part of its edge and a second pole opposing a flat surface of the first pole; and a high-voltage generator for applying a high voltage to the ionization electrode. 
     According to the ion generator of this arrangement, the discharge is prevented from concentrating on some of the pointed ends of the first pole that are closer to the second pole than the rest due to the working errors or mounting errors of the poles. This is presumed to be the result of the arrangement wherein the second pole in the ionization electrode opposes the flat surface of the first pole or the first pole does not present its pointed ends directly to the second pole. That is, the corona discharge has a lower directivity than in the arrangement wherein the pointed ends of the first pole are in direct face-to-face relation with the second pole. Accordingly, the corona discharge occurs in a stable manner free from the fear of developing into the spark discharge. Thus, the ion generator of the invention eliminates the possibility of troubles such as the burn of the electric circuit component of the high-voltage generator. Furthermore, the inventive ion generator is adapted to save power by reducing the current value of the primary winding of the transformer and to improve the air ionization efficiency. 
     According to one preferred structural arrangement of the inventions, the ion generator second pole has a discharge surface three-dimensionally curved into a convex surface. The ion generator features a further lowered directivity of the corona discharge. This leads to an even greater effect to prevent the discharge from concentrating on some of the pointed ends due to the working errors or mounting errors of the poles, ensuring a more stable corona discharge. As a result, the current value of the primary winding of the transformer can be further decreased while the air ionization efficiency is further increased. 
     In one preferred structural arrangement the first pole has a star-shaped electrode and the second pole has a spheric discharge surface. This arrangement also ensures a more stable generation of corona discharge. 
     The ion generator may have an arrangement wherein the second pole is shaped in the form of a flat plate inclined at a predetermined angle relative to the flat surface of the first pole. The arrangement provides an even greater effect to prevent the discharge from concentrating on some of the pointed ends due to the working errors or mounting errors of the poles. This eliminates the fear that the corona discharge may develop into the spark discharge, ensuring the stable generation of corona discharge. 
     Another preferred structural arrangement for the ion generator according to the inventions comprises a casing having an intake port and an exhaust port; an ionization electrode contained in the casing and including a first plate-like pole having a plurality of sawtooth-like pointed ends arranged linearly, and a second pole having a discharge surface defined by a cylinder or a part thereof and its generatrix extended in parallel with the pointed ends of the first pole; and a high-voltage generator for applying a high voltage to the ionization electrode. In this ion generator as well, the first pole does not present its pointed ends directly to the second pole whereas the discharge surface of the second pole is in the form of a convex surface defined by a cylinder or a part thereof. Hence, the directivity of the corona discharge is presumed to be lowered so that the corona discharge occurs in a stable manner as prevented from concentrating on some of the pointed ends due to the working errors or mounting errors of the poles. Accordingly, the current value of the primary winding of the transformer can be reduced for power saving while the air ionization efficiency can be increased. In addition, the elongated first and second poles are able to generate a large quantity of corona discharge at a time, thereby producing a large quantity of ozone. 
     According to another preferred structural arrangement, the first poles of the ion generator are disposed at plural places arranged peripherally of the second pole as presenting their respective flat surfaces to a peripheral surface of the second pole. This arrangement provides an even greater ozone generation. 
     The ion generator may have an arrangement wherein the first pole is formed with plural lines of pointed ends whereas the second pole is disposed in correspondence to each of the lines of pointed ends. This arrangement also provides a greater ozone generation. 
     It is preferred in the inventive ion generator that the first pole is formed from tungsten. In this case, the pointed ends of the first pole resist oxidation by ozone even if they are heated to about 1000° C. by the corona discharge so generated and hence, the subsequent generation of corona discharge will not be obstructed. In addition, tungsten does not act as a catalyst assisting the reaction of ozone on the surface of the first pole. 
     The ion generator of-the invention may be provided in an air charging system for supplying air to an internal combustion engine. In this case, a highly efficient combustion of the internal combustion engine is ensured. 
     The ion generator may have a structural arrangement wherein the intake port of the casing is provided with a dust filter whereas the exhaust port is provided with a sirocco fan for discharging ionized air. In this case, air filtered by the dust filter may be continuously introduced into the casing, efficiently ionized and discharged out of the casing. This provides for an efficient supply of ozone to a combustion apparatus such as a boiler, incinerator or the like. 
     The ion generator may have a structural arrangement wherein the intake port of the casing is provided with a dust filter whereas the exhaust port is provided with an air pump for discharging ionized air. In this case as well, the air filtered by the dust filter may be continuously introduced into the casing, efficiently ionized and discharged out of the casing. 
     The ion generator of the invention may further comprise a solar panel for converting the radiation energy of the solar light to an electrical energy, and a power source section comprising a storage battery for storing the electrical energy. In this case, the ion generator is portable because the current for corona discharge is supplied from the power source section. Equipped with the solar panel and designed for automatic storage of the electrical energy, the ion generator can be used for an extended period of time without recharging from utility power. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view showing an ion generator according to a first embodiment of the invention. 
         FIG. 2  is an enlarged sectional view taken on the line II—II in  FIG. 1 . 
         FIG. 3  is a sectional view showing an ion generator according to a second embodiment of the invention. 
         FIG. 4  is a plan view showing an ionization electrode according to the second embodiment hereof. 
         FIG. 5  is an enlarged sectional view taken on the line V—V in  FIG. 3 . 
         FIG. 6  is a sectional view showing an ionization electrode of an ion generator according to a third embodiment of the invention. 
         FIG. 7  is a sectional view showing an ionization electrode of an ion generator according to a fourth embodiment of the invention. 
         FIG. 8  is a perspective view showing an ion generator according to a fifth embodiment of the invention. 
         FIG. 9  is a sectional view showing an ionization electrode of an ion generator according to a sixth embodiment of the invention. 
         FIG. 10  is a sectional view showing a conventional ion generator. 
         FIG. 11  is a sectional view showing an ionization electrode of another conventional ion generator. 
     
    
    
     BEST MODES FOR CARRYING OUT THE INVENTION 
     Next, preferred embodiments of the invention will be described with reference to the accompanying drawings. 
       FIG. 1  is a sectional view showing an ion generator according to a first embodiment of the invention, whereas  FIG. 2  is an enlarged sectional view thereof taken on the line II—II in  FIG. 1 . 
     The ion generator is designed to ionize air for supplying the ionized air to an intake manifold interposed between an air cleaner and a cylinder within an internal combustion engine. 
     In the ion generator, a cylindrical casing  1  is formed with an intake port  11  at one end  1   a  thereof and with an exhaust port  12  at the other end  1   b  thereof. A space between the intake port  11  and the exhaust port  12  defines an air-flow passage A. A high-voltage generator  2  is disposed on an upstream side of the air-flow passage A, whereas an ionization electrode  3  is disposed on a downstream side thereof. 
     The casing  1  is formed from a synthetic resin, such as polyetherimde, having a connection port  14  for an intake pipe  4  protruded from one end la thereof and a connection port  15  for an exhaust pipe  5  protruded from the other end  1   b  thereof. The intake port  11  and the exhaust port  12  are coaxial with the casing  1 . The exhaust pipe  5  communicates with the intake manifold. 
     The high-voltage generator  2  has an arrangement wherein an electric circuit component including a transformer for high-voltage generation is housed in a case and molded therein by an epoxy resin or the like. The high-voltage generator  2  is positioned neutrally of the casing  1  as supported by ribs projecting from plural places of an outer periphery thereof, so that a gap S is defined along its outer peripheral surface and its end opposite the intake port  11  for allowing the air introduced into the casing  1  through the intake port  11  to flow therethrough. The high-voltage generator  2  is disposed coaxially with the intake port  11  and the exhaust port  12 . In the figure, the reference numeral  21  denotes a power cable whereas the numeral  22  denotes a ground lead. 
     The ionization electrode  3  includes (1) a positive pole portion  31  including a positive pole (a first pole)  31   a  of a thin star shape formed with pointed ends  31   b  on its outer circumference, and a support shaft  31   c ; (2) a negative pole portion  32  including a negative pole (a second pole)  32   a  in opposed relation with a flat surface of the positive pole  31   a , and a support shaft  32   b ; and (3) and a pair of disk-like support members  33  supporting the positive pole portion  31  and the negative pole portion  32 , respectively. The pointed end  31   b  is in the form of an equilateral triangle. 
     The positive pole  31   a  is connected to one pole of the high-voltage generator  2  while the negative pole  32   a  is connected to the other pole of the high-voltage generator  2 . In the ionization electrode  3 , the negative pole  32   a  is grounded and a positive high voltage from the high-voltage generator  2  is applied between the positive pole  31   a  and the negative pole  32   a . The positive pole  31   a  is formed from tungsten, which eliminates a fear that the pointed ends  31   b  may be oxidized by ozone and which does not act as a catalyst assisting the reaction of ozone on the surface of the positive pole  31   a . The negative pole  32   a  is formed of a stainless steel sheet three-dimensionally curved into a convex surface, or defined by a part of a spheric surface. 
     The pair of support members  33  are formed from an insulating material such as a diallyl phthalate resin, phenol resin, epoxy resin or the like, each having one vent hole  33   c  extended through its side for guiding the air, introduced into the casing  1  through the intake port  11 , to the exhaust port  12 . 
     The above arrangement allows a negative pressure in the intake manifold to introduce the air into the casing  1  through the intake port  11  and to move the introduced air through the gap S between the high-voltage generator  2  and the casing  1  to the exhaust port  12 . In this process, the air having passed the high-voltage generator  2  is ionized by corona discharge from the ionization electrode  3  and the air thus ionized is supplied to the intake manifold through the exhaust port  12  and the exhaust pipe  5 . 
     In this embodiment, the pointed ends  31   b  on the outer circumference of the positive pole  31   a  emits the corona discharge B along arcuate paths to the negative pole  32   a , the arcuate paths indicated by the dot lines in  FIG. 1 . This ion generator features the positive pole  31   a  with the pointed ends  31   b  radially extended toward an inner circumference of the casing  1  or not indirect face-to-face relation with the negative pole  32   a . As combined effects of this configuration and the convex surface of the negative pole  32   a , the corona discharge B is presumed to be lowered in directivity. Therefore, the discharge is prevented from concentrating on some of the pointed ends  31   b  that are closer to the negative pole  32   a  than the rest because of the working errors or mounting errors of the positive pole  31   a  and the negative pole  32   a . This permits the corona discharge B to be generated in such a stable manner free from the fear of developing into the spark discharge. As a result, the high-voltage generator  2  is free from troubles including the burn of the electric circuit component and the like. Furthermore, a current value of a primary winding of the transformer can be reduced to about ⅓ of that of the prior-art arrangement, so that the ion generator can save power. In addition, the ion generator can generate an increased quantity of ozone per unit time, achieving an efficient air ionization. 
       FIG. 3  is a sectional view showing an ion generator according to a second embodiment of the invention.  FIG. 4  is a plan view showing an ionization electrode of this embodiment whereas  FIG. 5  is a sectional view taken on the line V—V in  FIG. 3 . In the second embodiment, the ionization electrode  3  includes the positive pole portion  31  including a rectangular positive pole  31   a  and the support shaft  31   c ; and the negative pole portion  32  including a semi-cylindrical negative pole  32   a  and the support shaft  32   b . The positive pole  31   a  is formed with sawtooth-like pointed ends  31   b  along opposite longitudinal side edges thereof. The negative pole  32   a  is so disposed as to have its generatrix extended in parallel with the longitudinal direction of the positive pole  31   a.    
     Similarly to the first embodiment, the second embodiment is also arranged such that the pointed ends  31   b  of the positive pole  31   a  are not indirect face-to-face relation with the negative pole  32   a  and that the negative pole  32   a  is of a convex surface. Accordingly, the corona discharge B is prevented from concentrating on some of the pointed ends  31   b  due to the working errors or mounting errors of the poles. As a result, the corona discharge B occurs in a stable manner. 
     In the second embodiment, the positive pole  31   a  is formed with a large number of pointed ends  31   b  on the opposite ends thereof so that a large quantity of corona discharge B develop from the pointed ends  31   b  along the parallel longitudinal lines with respect to the positive pole  31   a . This provides for an efficient air ionization and the reduction of the current value of the primary winding of the transformer to about ⅓ of that of the prior-art arrangement. 
       FIG. 6  is a sectional view showing an ionization electrode  3  according to a third embodiment of the invention. In this ionization electrode  3 , a negative pole  32   a  is in the form of a cylinder whereas a plural number of rectangular positive poles  31   a  (four poles are shown in the figure) are arranged peripherally of the negative pole  32   a  as presenting their respective flat surfaces to a peripheral surface of the negative pole  32   a , the positive pole  31   a  formed with the sawtooth-like pointed ends  31   b  on its opposite side edges as shown in  FIG. 4 . The ionization electrode  3  of the third embodiment is also capable of generating a large quantity of corona discharge B in a stable manner. 
       FIG. 7  is a sectional view showing an ionization electrode  3  according to a fourth embodiment of the invention. The ionization electrode  3  includes two sets of one rectangular positive pole  31   a  formed with the sawtooth-like pointed ends  31   b  on its opposite side edges as shown in  FIG. 4 , and a pair of cylindrical negative poles  32   a , each of which is disposed in correspondence to each of the side edges of the positive pole and has a generatrix thereof extended in parallel with the corresponding pointed ends  31   b . The two sets of the positive pole and negative poles are arranged in a vertically symmetrical fashion. The pair of positive poles  31   a  sandwich an iron plate  34  therebetween. 
     Similarly to the ionization electrode of  FIG. 6 , this ionization electrode  3  is also capable of generating a large quantity of corona discharge B in a stable manner. 
       FIG. 8  is a perspective view showing an ionization electrode  3  of an ion generator according to a fifth embodiment of the invention. The ionization electrode  3  includes a rectangular positive pole  31   a  and a plate-like negative pole  32   a  opposing the positive pole  31   a  as inclined at a predetermined angle relative to the flat surface of the positive pole. The positive pole  31   a  is formed with the sawtooth-like pointed ends  31   b  on one longitudinal side edge thereof. 
     The ionization electrode  3  is also adapted to prevent the corona discharge from concentrating on some of the pointed ends  31   b , thus generating a large quantity of corona discharge B in a stable manner. 
     Although the forgoing embodiments illustrate the ion generator having the exhaust pipe  5  communicated with the intake manifold, the invention is not limited to this arrangement. The ion generator may be incorporated in a surge-tank or the like of the intake manifold. 
     In correspondence to the rotational speed of an internal combustion engine or the quantity of injected fuel, the generation of the corona discharge may be controlled by giving an instruction from a computer to change a voltage value or current value for the primary winding of the transformer or by changing the position of at least one of the positive pole  31   a  and the negative pole  32   a.    
     Although the foregoing embodiments illustrate the application where the ionized air is supplied to the internal combustion engine, the invention is not limited to this. The inventive ion generator may be adapted to supply the ionized air to, for example, combustion apparatuses such as boilers, incinerators and the like, deodorizers, sterilizers, air cleaners, or medical equipments designed to irradiate gangrenous area due to bacteria infection or affected area by Corixidae with ozone for treatment. Where the inventive ion generator is applied to the combustion apparatus such as a boiler, the exhaust pipe  5  of the ion generator may be communicated with an intake pipe of a burner so as to supply the air along with ozone to the burner. 
       FIG. 9  is a sectional view showing an ion generator according to a sixth embodiment of the invention. The ion generator essentially has the same arrangement as the ion generator of  FIG. 1 , except that the cylindrical casing  1  is provided with a dust filter  9  at one aperture  1   c  thereof and with a sirocco fan  10  at the other aperture id thereof. The sirocco fan  10  operates to introduce the air into the casing  1  through the dust filter  9  removing dust contained in the introduced air. 
     According to this embodiment, disposed in the air-flow passage A are a power source section  7 , the high-voltage generator along with an electric circuit component  6 , and the ionization electrode  3 , the power source section located on the uppermost stream side and followed by the others in this order. The power source section  7  contains therein a plurality of storage batteries  71  which are each connected to a solar panel  8  as an external component. The solar panel  8  converts the radiation energy of the solar light to an electrical energy which is stored in the storage batteries  71 . The power source section  7  is connected with the electric circuit component  6  which is connected with a power cable for a motor  10   a  of the sirocco fan  10 . The high-voltage generator  2  contains therein the electric circuit component for high-voltage generation. In addition to the storage batteries  71  for storing the electrical energy supplied from the solar panel  8 , the power source section  7  may further contain there in a storage battery for storing an electrical energy supplied from an AC power source. 
     The above arrangement is adapted to apply a high voltage between the positive pole  31   a  and the negative pole  32   a  of the ionization electrode  3  by using the power from the storage batteries  71  of the power source section  7 . Thus is generated the corona discharge between the positive and negative poles where the continuously introduced air through the dust filter  9  is ionized to generate ozone which is discharged from the casing  1  by means of the sirocco fan  10 . 
     This process generates the corona discharge B in a stable manner just as in the first embodiment, allowing for the reduction of the current value of the primary winding of the transformer and achieving an efficient air ionization. The ion generator of this embodiment uses the storage batteries  71  as the power source and hence is portable. Furthermore, the ion generator is equipped with the solar panel and designed for automatic storage of electrical energy so as to operate for an extended period of time without recharging the batteries with utility power. In this embodiment, the sirocco fan  10  is provided at the aperture  1   d . However, the fan at the aperture  1   d  may be replaced by an air pump  18 . 
     It is noted that the ion generator of the invention is not limited to the foregoing embodiments but various changes and modifications may be made thereto within the scope of the invention. For instance, the casing  1  may be formed square in section. 
     An alternative arrangement may be made wherein the polarities of the positive pole  31   a  and the negative pole  32   a  are reversed so that the positive pole  31   a  is grounded while a negative high voltage from the high-voltage generator  2  is applied.