Patent Publication Number: US-8966881-B2

Title: Device and method for combusting particulate substances

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device and a combustion method for combusting particulate matters in which particulate matters discharged from an internal combustion engine can be effectively combusted. 
     BACKGROUND ART 
     A variety of techniques have been studied to remove particulate matters (PM) in exhaust gas discharged from an internal combustion engine. In Patent Document 1, a technique is proposed in which particulate matters are captured by a ceramic honeycomb filter, and when the amount of the captured particulate matters exceeds the predetermined acceptable value, the captured particulate matters are heated to be combusted away. In Patent Document 2, in order to overcome the drawback that the ceramic honeycomb filter used in Patent Document 1 is expensive, fragile and hard to handle, and in order to decrease the power consumption required for burning away particulate matters, a technique is proposed in which a combustion heater is placed between a permeable filter made of ceramic fiber and a heat insulator, and heating is performed by using the heater to burn particulate matters with a timing controlling the inflow of particulate matter-containing gas. 
     Since the techniques in the above Patent Documents 1 and 2 are a technique in which particulate matters are captured by a heat resistant filter and the captured particulate matters are heated to be combusted away in an arbitrary timing, there is concern about a reduced filter life due to a rapid temperature change, a local heating or the like. To address such issues, in Patent Document 3, a technique is proposed in which cracking means for cracking without causing a rapid temperature change or a local heating on a filter which captures particulate matters, and oxidizing means for oxidizing the residual combustion particulate matters by ozone gas are combined. 
     In Patent Document 4, a technique is proposed in which manganese oxide-supported substrate in a gas flow channel is placed and adsorbed particulate matters are oxidatively decomposed, as well as the oxidation decomposition of particulate matters is accelerated by further containing active species such as an OH radical, an oxide atom, oxygen ion and ozone gas. In this technique, particulate matters are charged by electrons generated at the time of discharge in a plasma discharge device so that the adhesion to manganese oxide-supported substrate is accelerated, and the oxidative decomposition of the particulate matters by the catalysis of manganese oxide can be effectively performed, and further, since an OH radical and ozone generated in the plasma discharge device per se oxidatively decompose the particulate matters, the particulate matters can be removed by oxidation. 
     PRIOR ART REFERENCES 
     Patent Document 
     
         
         [Patent Document 1] Japanese Laid-Open Patent Application No. 2005-337153 
         [Patent Document 2] Japanese Laid-Open Patent Application No. 2008-64015 
         [Patent Document 3] Japanese Laid-Open Patent Application No. 2007-187136 
         [Patent Document 4] Japanese Laid-Open Patent Application No. 2009-50840 
       
    
     SUMMARY OF THE INVENTION 
     The Problems Solved by the Invention 
     However, the technique in the above Patent Document 3 includes a filter which captures and cracks particulate matters and generating means for generating an oxidizing and decomposing gas such as ozone gas, and the technique in the above Patent Document 4 includes a catalytic substrate on which particulate matters are adsorbed and heated to be oxidatively decomposed and generating means for generating an oxidizing and decomposing gas such as ozone gas. Both of the techniques require a heating device such as a heater and an oxidizing and decomposing gas generation device. For this reason, the device configuration is complex, large and heavy, and the complex, large and heavy device has a problem when vehicles or the like mounts it from the viewpoint of energy saving. Also, the filter has a problem such as clogging or heat-deterioration, and the oxidation catalyst has a problem such as catalyst life or heat-deterioration, too. 
     Although the related arts individually include a technique of cracking by a heater or the like, a high combustion efficiency cannot be obtained by heating using a heater, and therefore, timing of the combustion is controlled, inflow of a gas is controlled or the combustion is complemented by an ozone generating device or the like. 
     The present invention is devised to solve the above problems, and an object thereof is to provide a device and a method for combusting particulate matters in which particulate matters discharged from an internal combustion engine can be effectively combusted, and the device configuration is simple and does not become large and heavy. 
     Problem Resolution Means 
     The present inventor discovered a device configuration in which an effective combustion is realized and the device configuration is simple and not large and heavy by developing means for lengthening the time when particulate matters receive discharge energy, in order to effectively perform combustion of the particulate matter by silent discharge. Therefore, the present inventor completed the present invention. 
     Specifically, a combustion device for combusting particulate matters of the present invention for solving the above-described problems comprises: 
     an introduction portion which connects to an exhaust port of an internal combustion engine, and is used to introduce a particulate matter-containing gas discharged from the exhaust port; a charging unit which is provided on the downstream side of the introduction portion, and in which all or part of the particulate matters are negatively charged by bringing the particulate matter-containing gas into contact with; an electric discharge unit which is provided in an insulation pipe which is connected to the downstream side of the charging unit, and in which the particulate matters, all or part of which are negatively charged, are introduced into a silent discharge area and are combusted with an increased retention time, the silent discharge area being generated between an anode and a cathode; a discharge portion which is connected to the insulation pipe at the downstream side of the electric discharge unit and which discharges the combusted gas; and a power source unit which applies an electric field to the charging unit and the electric discharge unit. 
     By the present invention, all or part of particulate matters included in a particulate matter-containing gas discharged from an internal combustion engine are negatively charged by a charging unit. Further, the negatively charged particulate matters are introduced into a silent discharge area on the downstream side of the charging unit, and electrically attracted or repelled by constituting electrodes in order to reduce the speed of the negatively charged particulate matters. Therefore, time for the particulate matters to be retained in the silent discharge area can be increased, as well as the combustion efficiency of the particulate matters in the silent discharge area can be improved. As a result, efficient combustion can be realized, and further, miniaturization and weight reduction of the combustion device can be realized by a simple device configuration. 
     The combustion device for combusting particulate matters of the present invention has following three embodiments having the above technical features. 
     In the first embodiment of the combustion device for combusting particulate matters, the introduction portion has a gas flow conversion member which changes the flow of the particulate matter-containing gas to a spiral flow, the charging unit has a ring anode provided along the internal circumference of the pipe where the spiral flow flows, and the electric discharge unit has a cylindrical cathode provided on inner wall of the insulation pipe, a cylindrical dielectric provided inside the cathode and a cylindrical mesh anode is spaced from the cylindrical dielectric at predetermined gap on the inside of the cylindrical dielectric. 
     In the first embodiment of the present invention, the particulate matters in the gas flow changed to the spiral flow by the gas flow conversion member have negative space charge (negative charge) gathered around the ring anode. The particulate matters having the negative space charge are attracted by the electrostatic force of the cylindrical mesh anode and enter the silent discharge area while flowing on the spiral gas flow at the vicinity of the inner wall of the pipe. The speed of the flow of the particulate matters which enter the silent discharge area is reduced by Coulomb force at the silent discharge area extending in the longitudinal direction of the pipe. As a result, the particulate matters obtain much discharge energy and can be efficiently combusted. 
     In the second embodiment of the combustion device for combusting particulate matters, the charging unit has a planar mesh anode provided orthogonal to a flow channel of the particulate matter-containing gas, the electric discharge unit has: a cylindrical cathode spaced from the inner wall of the insulation pipe at predetermined gap; a cylindrical dielectric provided inside the cathode; a cylindrical mesh anode spaced from the cylindrical dielectric on the inside of the cylindrical dielectric; and a gas flow conversion member which introduces particulate matters charged by the planar mesh anode into the silent discharge area between the cylindrical dielectric and the cylindrical mesh anode. 
     In the second embodiment of the present invention, the particulate matters in the gas flow have negative space charge gathered around the planar mesh anode. The particulate matters have negative space charge are guided by the gas flow conversion member to the silent discharge area extending in the longitudinal direction of the pipe, and the speed of the flow of the particulate matters is reduced by Coulomb force at the silent discharge area. As a result, the particulate matters obtain much discharge energy and can be efficiently combusted. 
     In the third embodiment of the combustion device for combusting particulate matters, the charging unit has a planar mesh anode provided orthogonal to a flow channel of the particulate matter-containing gas; and the electric discharge unit has: a planar mesh cathode provided orthogonal to the flow channel; and an anode spaced from the planar mesh cathode at predetermined gap on the upstream side of the planar mesh cathode, and the predetermined gap forms a silent discharge area. 
     In the third embodiment of the present invention, the particulate matters in the gas flow have negative space charge gathered around the planar mesh anode. The particulate matters have negative space charge are introduced into the silent discharge area through the anode, and the particulate matters are electrically repelled by the planar mesh cathode and the speed of the particulate matters is reduced. As a result, the particulate matters obtain much discharge energy and can be efficiently combusted. 
     The combustion method for combusting particulate matters of the present invention for solving the above-described problems comprises: negatively charging all or part of particulate matters included in a particulate matter-containing gas discharged from an internal combustion engine; electrically attracting or repelling the negatively charged particulate matters in order to reducing the speed of the negatively charged particulate matters; and increasing retention time for the particulate matters to be retained in a silent discharge area in order to extend time for applying discharge energy at the silent discharge area. 
     By the present invention, since the particulate matters are combusted in a state that the retention time in the silent discharge area is increased, the combustion efficiency in the silent discharge area can be increased. As a result, an efficient combustion can be realized. 
     In the first embodiment of the combustion method for combusting particulate matters, the retention time is increased at the silent discharge area by electrostatically attracting the negatively charged particulate matters to a mesh anode which is provided on the downstream side of a flow channel of the particulate matter-containing gas. 
     In the second embodiment of the combustion method for combusting particulate matters, the retention time is increased at the silent discharge area by electrostatically attracting the negatively charged particulate matters to a mesh anode which is provided on the downstream side of a flow channel of the particulate matter-containing gas. 
     In the third embodiment of the combustion method for combusting particulate matters, the retention time is increased at the silent discharge area by attracting the negatively charged particulate matters to a mesh anode and depositing the negatively charged particulate matters on the mesh node, the mesh anode being provided on the downstream side of a flow channel of the particulate matter-containing gas. 
     Efficacy of the Invention 
     By the combustion devise and the method combustion for combusting particulate matters of the present invention, all or part of particulate matters included in a particulate matter-containing gas discharged from an internal combustion engine are negatively charged by a charging unit. Further, the negatively charged particulate matters are introduced into a silent discharge area on the downstream side of the charging unit, and electrically attracted or repelled by constituting electrodes in order to reduce the speed of the negatively charged particulate matters. Therefore, time for the particulate matters to be retained in the silent discharge area can be increased, as well as the combustion efficiency of the particulate matters in the silent discharge area can be improved. As a result, efficient combustion can be realized, and further, miniaturization and weight reduction of the combustion device can be realized by a simple device configuration. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is a layout drawing of a combustion device for combusting particulate matters of the present invention. 
         FIG. 2  is a schematic configuration diagram illustrating a first embodiment of a combustion device for combusting particulate matters of the present invention. 
         FIGS. 3A ,  3 B and  3 C are schematic configuration diagrams illustrating one example of a gas flow conversion member. 
         FIG. 4  is a schematic configuration diagram illustrating another example of a gas flow conversion member. 
         FIGS. 5A and 5B  are configuration diagrams illustrating one example of a ring anode. 
         FIGS. 6A and 6B  are a schematic configuration diagram illustrating one example of an electric discharge unit. 
         FIG. 7  is a schematic configuration diagram illustrating a second embodiment of a combustion device for combusting particulate matters of the present invention. 
         FIG. 8  is a schematic configuration diagram illustrating a third embodiment of a combustion device for combusting particulate matters of the present invention. 
         FIG. 9  is a schematic configuration diagram illustrating one example of an electric discharge unit viewed from an introduction portion side. 
     
    
    
     EMBODIMENT OF THE INVENTION 
     Next, embodiments of the present invention will be described. The present invention includes the scope including the technical idea thereof, and is not limited to the following description, drawings or the like. 
     A combustion device and a combustion method for combusting particulate matters of the present invention have means for lengthening the time for receiving discharge energy in order to perform combustion efficiently in silent discharge. The term, “silent discharge” refers to discharge which occurs when one or both of electrode plates with a fixed distance in between is(are) covered with an insulator (dielectric) and an alternating voltage is applied to the electrode plates. Also, the silent discharge is referred to as dielectric barrier discharge. Since the electrode(s) is(are) covered with an insulator(s), an electric charge cannot flow into the electrode(s), and therefore, a large current does not flow. For this reason, in silent discharge, a sound is not heard unlike the case of spark discharge or corona discharge, and thus such discharge is referred to as “silent discharge.” 
     The basic configuration has means for negatively charging all or part of particulate matters included in a particulate matter-containing gas discharged from an internal combustion engine, and means for lengthening time for the particulate matters to be retained in a silent discharge area by reducing the speed of the particulate matters by electrically attracting or repelling the particulate matters in the silent discharge area. By such means, time for applying discharge energy at the silent discharge area can be increased and the particulate matters can be combusted in a state that the retention time in the silent discharge area is increased. As a result, the combustion efficiency in the silent discharge area can be increased, and efficient combustion can be realized. 
     As shown in  FIG. 1 , combustion device  10  for combusting particulate matters of the present invention is provided somewhere on muffler  3  (made of, for example, stainless steel) which is connected to exhaust port  2  of internal combustion engine  1 . Generally, combustion device  10  has introduction portion  8  and discharge portion  9  as shown in  FIG. 1  and  FIG. 2 . Introduction portion  8  is connected to exhaust port  2  of internal combustion engine  1 ; and discharge portion  9  is connected to muffler  3 . In order to effectively use the remaining heat from engine  1 , combustion device  10  is preferably connected near engine  1  as shown in  FIG. 1 . The reference sign  4  in  FIG. 1  represents a power source unit for applying a voltage to an electric discharge unit performing silent discharge. 
     As shown in  FIG. 2 ,  FIG. 7  and  FIG. 8 , specifically, combustion device  10  includes: introduction portion  8  which is connected to exhaust port  2  of internal combustion engine  1  and which is used to introduce particulate matter-containing gas  5  discharged from exhaust port  2 ; charging unit ( 11 ,  21 ,  31 ) which is provided on the downstream side of introduction portion  8 , and in which all or part of particulate matters  6  included in particulate matter-containing gas  5  are negatively charged by bringing particulate matter-containing gas  5  in contact with; electric discharge unit ( 15 ,  25 ,  35 ) which is provided in insulation pipe  100  connected to the downstream side of charging unit ( 11 ,  21 ,  31 ), and in which particulate matters  6 ′, all or part of which are negatively charged, are introduced into a silent discharge area (A 1 , A 2 , A 3 ) which is generated between an anode and a cathode, and are combusted with an increased retention time; discharge portion  9  which is connected to insulation pipe  100  at the downstream side of electric discharge unit ( 15 ,  25 ,  35 ) and which discharges combusted gas  7 ; and power source unit  4  which applies an electric field to charging unit ( 11 ,  21 ,  31 ) and electric discharge unit ( 15 ,  25 ,  35 ). 
     There are three embodiments, the first to the third embodiments, of the present invention in which negatively charged particulate matters  6 ′ are electrically attracted or repelled to reduce the speed of negatively charged particulate matters  6 ′. 
     As shown in  FIG. 2 , the first embodiment of a combustion device and a combustion method for combusting particulate matters is configured so as to electrostatically attract negatively charged particulate matter  6 ′ to cylindrical mesh anode  133 , which is provided on the downstream side of a flow channel of the particulate matter-containing gas  5 , and to retain negatively charged particulate matter  6 ′ at silent discharge area A 1 , in order to increase the retention time when negatively charged particulate matter  6 ′ is retained at silent discharge area A 1 . 
     As shown in  FIG. 7 , the second embodiment of a combustion device and a combustion method for combusting particulate matters is configured so as to attract negatively charged particulate matter  6 ′ to cylindrical mesh anode  233 , which is provided on the downstream side of the flow channel, and can capture particulate matter  6 ′, and to deposit particulate matter  6 ′ on anode  233  in order to increase the retention time when negatively charged particulate matter  6 ′ is retained at silent discharge area A 2 . 
     As shown in  FIG. 8 , the third embodiment of a combustion device and a combustion method for combusting particulate matters is configured so as to electrostatically repel negatively charged particulate matter  6 ′ by planar mesh cathode  331 , which is provided on the downstream side of the flow channel, and to deposit negatively charged particulate matter  6 ′ on cathode  331 , in order to increase the retention time when negatively charged particulate matter  6 ′ is retained at silent discharge area A 3 . 
     By such a combustion device and a combustion method for combusting particulate matters of the present invention, all or part of particulate matters  6  included in particulate matter-containing gas  5  discharged from internal combustion engine  1  are negatively charged by charging unit ( 11 ,  21 ,  31 ); negatively charged particulate matters  6 ′ are introduced into silent discharge area (A 1 , A 2 , A 3 ) and electrically attracted or repelled by constituting electrodes ( 13 ,  23 ,  33  or  14 ,  24 ,  34 ), in order to reduce the speed of negatively charged particulate matters  6 ′. As a result, and retain time for particulate matters  6 ′ to be retained in silent discharge area (A 1 , A 2 , A 3 ) is increased, and the particulate matters can be combusted in such a state. By such an invention, the combustion efficiency in silent discharge area (A 1 , A 2 , A 3 ) can be improved and efficient combustion can be realized, and further, miniaturization and weight reduction of the device can be realized by a simple device configuration. 
     EMBODIMENT 
     Representative three embodiments of a combustion device for combusting particulate matters of the present invention will be described in detail with reference to the drawings. 
     First Embodiment 
     As shown in  FIG. 2 , the first embodiment of combustion device  10 A for combusting particulate matters is configured so as to electrostatically attract particulate matter  6 ′ on which negative charge  122  is charged to cylindrical mesh anode  133 , which is provided on the downstream side, and to retain particulate matter  6 ′ at silent discharge area A 1 , in order to increase the retention time at silent discharge area A 1 . Specifically, as shown in  FIG. 2 , the device  10 A includes introduction portion  8 , charging unit  11 , electric discharge unit  15 , discharge portion  9  and power source unit  4 . 
     As shown in  FIG. 2 , combustion device  10 A is preferably configured to have introduction portion  8 , charging unit  11 , electric discharge unit  15  and discharge portion  9  in the order mentioned toward the downstream side in insulation pipe  100 . Each of the portions may be connected to each other as a separate member in the order mentioned toward the downstream side. Further, combustion device  10 A is preferably configured to have, as a substrate, ceramic insulation pipe  100  having heat insulating properties and electrical insulating properties. The term “upstream side” herein refers to the internal combustion engine side or the introduction portion side, and the term “downstream side” herein refers to the muffler side or the discharge portion side. Each component will now be described. 
     (Introduction Portion) 
     As shown in  FIG. 1  and  FIG. 2 , introduction portion  8  is connected to exhaust port  2  of internal combustion engine  1 , and is used to introduce particulate matter-containing gas  5  discharged from exhaust port  2 . Introduction portion  8  is preferably integrated with insulation pipe  100  (for example, ceramic insulation pipe) including electric discharge unit  15  and charging unit  11 . Introduction portion  8  may be formed by an introduction pipe which is a separate member, and connected to insulation pipe  100 . Particulate matter-containing gas  5  to be introduced includes particulate matter  6  which is a target. 
     As illustrated in  FIG. 3  and  FIG. 4 , introduction portion  8  has gas flow conversion member  101  which changes the flow of particulate matter-containing gas  5  into spiral flow  107 . 
       FIGS. 3A ,  3 B and  3 C are schematic configuration diagrams illustrating one example of a gas flow conversion member.  FIG. 3A  is a schematic diagram,  FIG. 3B  is a view from the upstream side and  FIG. 3C  is a view from the downstream side. Gas flow conversion member  101 A as shown in  FIG. 3  generates spiral flow  107  by allowing a gas flow to pass through a plurality of twisted flow channels  104 , and includes a plurality of inflow ports  102  and as many outflow ports  103 . Particulate matter-containing gas  5  which is input from inflow port  102  is converted into spiral flow  107  when the particulate matter-containing gas passes through flow channel  104  and is output from outflow port  103 . The numbers of inflow ports  102  and outflow ports  103  are not limited, and the numbers are two or more, and preferably three or four individually. Each of flow channel  104  is twisted clockwise or counterclockwise toward outflow port  103 , and further, each of flow channel  104  is provided with a prescribed angle θ (for example, from 15° to 45°) such that each of opening of outflow port  103  faces to the inner wall of insulation pipe  100 . 
     In the example of  FIG. 3 , particulate matter-containing gas  5  is divided into four gas flows at four inflow ports  102  and the each of divided gas flows pass through flow channel  104  and flow out as spiral flow  107  from outflow port  103 , respectively. Each of inflow ports  102  and each of outflow ports  103  are placed at regular intervals individually. This member material preferably has heat resistance and corrosion resistance. Gas flow conversion member  101 A is not limited to the example as shown in  FIG. 3  as long as the member has such a principle. 
       FIG. 4  is a schematic configuration diagram illustrating another example of a gas flow conversion member. Gas flow conversion member  101 B as shown in  FIG. 4  generates spiral flow  107  by rotation of blade  106  attached to propeller shaft  105 . Propeller shaft  105  may freely rotate, or be driven to rotate. Generally, a device which is driven to rotate is used. Particulate matter-containing gas  5  is converted into spiral flow  107  by rotation of propeller shaft  105  and blade  106 . The number of blades  106  is not limited, and generally three or four. This member material also preferably has heat resistance and corrosion resistance. 
     (Charging Unit) 
     Charging unit  11  is a unit which is provided on the downstream side of introduction portion  8 , and in which negative space charge  122  (also simply referred to as “negative charge”) is charged on all or part of particulate matter  6  included in particulate matter-containing gas  5  by bringing particulate matter-containing gas  5  into contact with. In the first embodiment, as shown in  FIG. 2  and  FIG. 5 , ring anode  121  provided along the internal circumference of the pipe where spiral flow  107  flows is preferably used. Specifically, ring anode  121  is spaced at predetermined gap from the internal circumference surface orthogonal to the longitudinal direction of the pipe. Ring anode  121  shown in  FIG. 5  is an example that thin ring metal electrode is held in ring member  125  by four supporting members  124 . Positive high voltage is applied to the thin ring metal electrode from power source unit  4 . The thin ring metal electrode as ring anode  121  is generally formed by stainless steel or the like, and has a conductor diameter of about 1 mm, but not limited thereto. 
     Since negative charge  122  gathers around ring anode  121 , particulate matter-containing gas  5  which flows along the inner wall of the pipe as spiral flow  107  is in contact with anode  121 . As a result, particulate matter  6  included in particulate matter-containing gas  5  has negative charge  122 , and negatively charged particulate matter  6 ′ flows in the pipe as spiral flow  107 . Since spiral flow  107  provide particulate matter  6 ′ with a centrifugal force, a force in the inner wall direction of the pipe is applied to particulate matter  6 ′, and therefore, spiral flow  107  proceeds along the inner wall of the pipe. 
     (Discharge Device) 
     As shown in  FIG. 2  and  FIG. 6 , electric discharge unit  15  is a unit which is provided in insulation pipe  100  which is connected to the downstream side of charging unit  11 , and in which particulate matters  6 ′, on all or part of which negative charge  122  is charged, are introduced into silent discharge area A 1  which is generated between anode  133  and cathode  131 , and are combusted with an increased retention time. Specifically, as shown in  FIG. 6 , electric discharge unit  15  has: cylindrical cathode  131  provided on the inner wall of insulation pipe  100 ; cylindrical dielectric  132  provided inside cathode  131 ; and cylindrical mesh anode  133  spaced from inside of dielectric  132  at predetermined gap G. 
     Electric discharge unit  15  is preferably provided in ceramic insulation pipe  100  having heat resistance, heat insulating properties and electrical insulating properties. Not only in electric discharge unit  15 , but also in the above-mentioned charging unit  11 , it is preferable that electric discharge unit  15  and charging unit  11  be provided in integrated insulation pipe  100  as shown in  FIG. 2 . The inner diameter of insulation pipe  100  is not limited, and generally, in the range of about 20 to 100 mm. 
     On the inner surface of insulation pipe  100 , cylindrical cathode  131  is provided, and cathode  131  may be a stainless metal body having a thickness of, for example, about 0.1 mm. Insulation pipes  134 ,  134  are provided on the both ends (the upstream end and the downstream end) of cylindrical cathode  131  in the longitudinal direction. Cathode  131  may be in close contact with insulation pipe  100 , and spaced from insulation pipe  100  at a little gap as shown in  FIG. 6 . 
     Cylindrical dielectric  132  is provided inside (on the center side of the pipe, same as below) the above-mentioned cylindrical cathode  131 . Preferably, dielectric  132  is ceramic dielectric having, for example, a thickness of 1 mm, and specifically, formed by alumina or the like. Generally, the dielectric  132  is provided in close contact with cathode  131 . 
     Preferably, cylindrical mesh anode  133  is formed on the inside of cylindrical dielectric  132 , and spaced from dielectric  132  at gap G, which is about 1 mm, for example. Anode  133  has mesh structure which has openings allowing particulate matter  6 ′ to pass through. The size of the opening is such that, for example, particulate matter  6  of 2 μm can freely pass through the opening, but not limited. The material of anode  133  is not limited, but tungsten mesh having high heat resistance is preferably used. For example, a tungsten mesh having a wire diameter of 0.4 mm and 20 mesh/inch can be exemplified. 
     A high voltage with a high frequency is applied between cathode  131  and anode  133  from power source unit  4  in order to generate silent discharge. Since particulate matter  6 ′ flows on spiral flow  107  near the inner wall of the pipe, duration time of discharging in silent discharge area A 1  becomes longer than the duration time when the particulate matter  6 ′ flows straightly in the pipe. Further, since particulate matter  6 ′ which flows on the inner wall side of the pipe passes through the mesh opening of anode  133  by the centrifugal force based on spiral flow  107 , it is easy that particulate matter  6 ′ flows in silent discharge area A 1 , and receives silent discharge. Further, since particulate matter  6 ′ is negatively charging and then, attracted to anode  133  by Coulomb force, and particulate matter  6 ′ tends to retain in silent discharge area A 1  for a long time. As a result of this retention of particulate matter  6 ′ in silent discharge area A 1 , particulate matter  6 ′ receives the discharge energy of the silent discharge for a long time, more efficient combustion is performed due to Joule heat by a large discharge energy or the residual heat of combustion of particulate matter  6 ′. 
     Toxic components (NOx, SOx) included in particulate matter-containing gas  5  can be reformed and removed by a high electric field in silent discharge area A 1 . 
     (Power Source Unit) 
     Power source unit  4  is a unit which applies an electric field to charging unit  11  and electric discharge unit  15 . As shown in  FIG. 2  and  FIG. 6 , power source unit  4  has high voltage and high frequency generator  141  and power source  142 . Power source  142  may be a direct-current power source or alternating-current power source, and may be a cell (battery). From such power source  142 , a direct voltage or an alternating voltage is transmitted to high voltage and high frequency generator  141 . In high voltage and high frequency generator  141 , the voltage is converted into a high voltage with high frequency or high pulse voltage. 
     The positive voltage terminal of high voltage and high frequency generator  141  is connected to ring anode  121  of charging unit  11  and cylindrical mesh anode  133  of electric discharge unit  15 . On the other hand, the negative voltage terminal is connected to cylindrical cathode  131 . Silent discharge is generated between cylindrical mesh anode  133  to which the positive voltage terminal is connected and cylindrical cathode  131  to which the negative voltage terminal is connected. Ring anode  12  to which a positive voltage terminal is connected attracts negative space charge  122 . 
     (Discharge Portion) 
     Discharge portion  9  is connected to insulation pipe  100  on the downstream side of electric discharge unit  15 , and discharges combusted gas  151 . Herein, the term “connected to insulation pipe  100 ” means that an discharge portion is formed by a discharge pipe which is a separate member, and the discharge portion is connected to insulation pipe  100  (see  FIG. 7  and  FIG. 8 ), or one integrated with insulation pipe  100  which the end of the downstream side is used as a discharge portion (see  FIG. 2 ). The combustion treated gas becomes exhaust gas  151 , and, as shown in  FIG. 1 , discharged from muffler  3  connected to the downstream side of combustion device  10 . 
     As described above, in the first embodiment of combustion device  10 A, particulate matter  6  in the gas flow converted to spiral flow  107  by gas flow conversion member  101  has negative space charge  122  gathered around ring anode  121 . While particulate matter  6 ′ having negative space charge  122  flows on spiral flow  107  near the inner wall of a pipe, particulate matter  6 ′ is attracted also by cylindrical mesh anode  133  and flows in silent discharge area A 1 . The speed of the flow of particulate matter  6 ′ which flows in silent discharge area A 1  is reduced by Coulomb force at silent discharge area A 1  extending in the longitudinal direction of the pipe. As a result, the particulate matters obtain much discharge energy and can be efficiently combusted. 
     By such combustion device  10 A, the combustion of particulate matter is performed under a more power saving condition, by being connected near exhaust port  2  of engine  1 , preventing heat loss by covering the combustion portion by insulation pipe  100 , increasing the retention time at silent discharge area A 1  by Coulomb force by providing particulate matter  6  with negative charge  122 , and using a high frequency or high pulse discharge. Further, other toxic components (NOx, SOx) included in particulate matter-containing gas  5  can be decomposed and removed. Since combustion device  10  of the present invention which can realize such an effective combusting is simple and small and has light weight, combustion device  10  is suitable for vehicle or the like. 
     Second Embodiment 
     As shown in  FIG. 7 , the second embodiment of combustion device  10 B for combusting particulate matters is configured so electrostatically attract particulate matter  6 ′, which has negative charge  222 , to cylindrical mesh anode  233  which is provided on the downstream side of the flow channel, and can capture particulate matter  6 ′ and to deposited particulate matter  6 ′ on cylindrical mesh anode  233 , in order to increase the retention time at silent discharge area A 2 . Specifically, as shown in  FIG. 7 , the combustion device  10 B includes introduction portion  8 , charging unit  21 , electric discharge unit  25 , discharge portion  9  and power source unit  4  in the order mentioned toward the downstream side. Although, in the example in  FIG. 7 , charging unit  21  and electric discharge unit  25  are configured as one in insulation pipe  100 , charging unit  21  and electric discharge unit  25  may not be necessarily configured as one. 
     In the same manner as in the first embodiment, introduction portion  8  is connected to exhaust port  2  of internal combustion engine  1 , and particulate matter-containing gas  5  discharged from exhaust port  2  is introduced into introduction portion  8 . In the example in  FIG. 7 , introduction portion  8  is formed by pipe  201  which has a smaller diameter than that of insulation pipe  100 . Introduction portion  8  is connected such that pipe  201  is inserted into the upstream end of insulation pipe  100 . On the other hand, in the same manner as in the first embodiment, discharge portion  9  is also connected to insulation pipe  100  and discharges combusted gas  151 . In the example in  FIG. 7 , discharge portion  9  is formed by pipe  241  having a diameter smaller than those of insulation pipe  100  and pipe  201 . Discharge portion  9  is connected such that pipe  241  is inserted into the downstream end of insulation pipe  100  via coaxial ring  242 . Coaxial ring  242  is an important member which secures the below-described silent discharge area A 2  and inner wall flow channel  243 , and has a width in the radial direction by which these flow channels can be secured. 
     The term “upstream side” herein refers to the side of internal combustion engine  1  as shown in  FIG. 1 , and the term “downstream side” herein refers to the side of muffler  3  as shown in  FIG. 1 . In the illustrated example, since pipe  241  which constitutes discharge portion  9  is provided so as to function as a supporting member of cylindrical mesh anode  233 , pipe  241  preferably has insulation properties. On the other hand, since pipe  201  which constitutes introduction portion  8  is not in contact with an electrode, it may be a metal pipe made of stainless steel or the like, and may be an insulation pipe. 
     The configurations of introduction portion  8  and discharge portion  9  are not limited to the examples of connecting pipes illustrated in the figures. Namely, it is only necessary for pipe  201  which constitutes introduction portion  8  to be connected to insulation pipe  100  which constitutes charging unit  21  and electric discharge unit  25 . Also, it is only necessary for pipe  241  which constitutes introduction portion  9  to be connected to insulation pipe  100  which constitutes charging unit  21  and electric discharge unit  25 . Although, in the illustrated example, silent discharge area A 2  and inner wall flow channel  243  is secured by configuring pipe  241  to have a smaller diameter, it is unnecessary to use pipe  241  having a smaller diameter. Silent discharge area A 2  and inner wall flow channel  243  are formed by using another member. 
     In introduction portion  8 , a gas flow conversion member which converts particulate matter-containing gas  5  into spiral flow  107  as shown in  FIG. 3  and  FIG. 4  is not provided. However, plate-like flow channel control member  237  is provided as a gas flow conversion member which controls the flow channel of particulate matter-containing gas  5  which is introduced. Plate-like flow channel control member  237  is used as a member which interrupts the flow of particulate matter-containing gas  5 , which is introduced into introduction portion  8  and proceeds in the longitudinal direction of insulation pipe  100 , and flows particulate matter-containing gas  5  into silent discharge area A 2  from the periphery of plate-like flow channel control member  237 . The shape of this plate-like flow channel control member  237  is preferably a disk shape when the cross-sectional shape of electric discharge unit  25  is circle, and preferably a regular tetragon when the cross-sectional shape of electric discharge unit  25  is tetragon. 
     Plate-like flow channel control member  237  is supported by pillar  238  extending from the center portion of the below-mentioned planar mesh anode  221 . On the other hand, the periphery of plate-like flow channel control member  237  supports the upstream side of cylindrical mesh anode  233 . The downstream side of cylindrical mesh anode  233  is supported by insulation pipe  241  which constitutes discharge portion  9 . Insulation pipe  241  is fixed to insulation pipe  100  via coaxial ring  242  which is inserted into the periphery thereof. 
     The material of plate-like flow channel control member  237  is not limited. When cylindrical mesh anode  233  and planar mesh anode  221  placed on the upstream side are electrically connected as shown in  FIG. 7 , cylindrical mesh anode  233  and planar mesh anode  221  may be, for example, formed by metal such as stainless steel. In this case, pillar  238  is also formed by an electrically conducting material. On the other hand, plate-like flow channel control member  237  may be formed by a metal mesh or an electrically insulating mesh, when a positive voltage is applied to planar mesh anode  221  by another wiring, or when pillar  238  is used simply as a supporting member to support from the upstream side of plate-like flow channel control member  237  without making planar mesh anode  221  function as an electrode. In this case, pillar  238  is composed of an insulating material. 
     On the upstream side of plate-like flow channel control member  237  and on the downstream side of introduction portion  8 , planar mesh anode  221  as charging unit  21  is provided orthogonal to the flow channel of particulate matter-containing gas  5 . Planar mesh anode  221  is supported by cylindrical dielectric  234  so that the periphery of cylindrical dielectric  234  is inserted in the upstream end of cylindrical dielectric  234 . On the center portion of planar mesh anode  221 , pillar  238  for supporting the above-mentioned plate-like flow channel control member  237  which is placed on the downstream side of planar mesh anode  221  is provided. 
     In the same manner as in the first embodiment, planar mesh anode  221  is a member used to bring particulate matter-containing gas  5  into contact with, and to negatively-charge all or part of particulate matter  6  included in particulate matter-containing gas  5  by negative charge  22 . For this reason, a positive voltage is preferably applied to planar mesh anode  221  from power source unit  4 . Since negative space charge (negative charge)  222  gathers to planar mesh anode  221  on which a positive voltage is applied, particulate matter  6  included in particulate matter-containing gas  5  which passes through planar mesh anode  221  has negative charge  222 . Namely, particulate matter  6  is negatively-charged by passing through planar mesh anode  221 , and flows to the downstream side. The flow of particulate matter  6 ′ which flowed to the downstream side is controlled by plate-like flow channel control member  237  and flows into silent discharge area A 2  by electrically attracting to cylindrical mesh anode  233 . 
     Planar mesh anode  221  may have a mesh structure which has, for example, an opening through which particulate matter  6  of 2 μm can freely pass. The material of planar mesh anode  221  is not limited, and preferably a heat resistant metal mesh. For example, a tungsten mesh or a tungsten alloy mesh is preferably used, but not limited thereto. For example, a tungsten mesh having a wire diameter of 0.4 mm and 20 mesh/inch can be used. 
     As shown in  FIG. 7 , electric discharge unit  25  in the second embodiment is a unit which is provided in insulation pipe  100  which is connected to the downstream side of charging unit  11 . Further, electric discharge unit  25  is used to introduce all or part of the particulate matter  6 ′ which has negative charge  222 , into silent discharge area A 2  which is generated between anode  233  and cathode  235 , in order to increase an increased retention time and combust the particulate matter  6 ′. Specifically, electric discharge unit  25  has: cylindrical cathode  235  spaced from the inner wall of insulation pipe  100  at a predetermined gap which is flow channel  243 ; cylindrical dielectric  234  provided inside cathode  235 ; cylindrical mesh anode  233  spaced from the inside of dielectric  234  at predetermined gap (not limited, and for example, in a range of about 0.5 mm to 3 mm). 
     Cylindrical cathode  235  is spaced from the inner wall side of insulation pipe  100  at a predetermined gap (not limited, but, for example, in a range of 1 mm to 10 mm), and may be formed, for example, by a metal body of stainless steel having a thickness of about 0.5 mm. In the example of  FIG. 7 , cathode  235  is provided in close contact with the external surface of the below-described cylindrical dielectric  234 . Flow channel (inner wall flow channel)  243  is formed between cathode  235  and insulation pipe  100 . 
     Cylindrical dielectric  234  is provided inside the above-mentioned cylindrical cathode  235 . Dielectric  234  is fixed on insulation pipe  100  by a plurality of supporting bolts  236 . Dielectric  234  is a ceramic dielectric having a thickness of about 1 mm. Specifically, dielectric is preferably formed by a material such as alumina. Dielectric  234  fixed in the insulation pipe by supporting bolts  236  has a space which is able to form inner wall flow channel  243  between dielectric  234  and insulation pipe  100 . 
     Cylindrical mesh anode  233  is preferably formed by a heat resistant metal fiber mesh (for example, wire diameter (20 μm), porosity: 80%, thickness: 1.3 mm) For example, stainless metal fiber mesh is preferably used, but not limited thereto. The openings of the mesh may have such a size that, for example, particulate matter  6 ′ of 0.1 μm does not easily pass the mesh and the mesh can capture. 
     Since this cylindrical mesh anode  233  can capture particulate matter  6 ′, particulate matter  6 ′ is provided with sufficient discharge energy while particulate matter  6 ′ introduced into silent discharge area A 2  by circular plate-like flow channel control member  237  is captured by the mesh structure. As a result, efficient combustion can be realized. After the combustion, particulate matter  6 ′ becomes combustion gas  250  and passes through the mesh and is discharged from discharge portion  9  as exhaust gas  151 . 
     As shown in  FIG. 7 , flow channel  243  having the above-mentioned prescribed gap (not particularly limited, but, for example, in a range of 1 mm to 10 mm) is formed between cylindrical dielectric  234  provided with cylindrical cathode  235  on the insulation pipe  100  side and insulation pipe  100 . The gas flow which flows in inner wall flow channel  243  is different from the gas flow introduced into silent discharge area A 2  by plate-like flow channel control member  237 . However, particulate matter-containing gas  5  which has flowed in inner wall flow channel  243  turns around (goes back) at the downstream end portion of the pipe structure (turn-around portion)  244  to flow into silent discharge area A 2 . 
     Since particulate matter  6  in particulate matter-containing gas  5  which has flowed into silent discharge area A 2  cannot pass through the metal fiber mesh structure of cylindrical mesh anode  233  and is captured by the structure, particulate matter  6  receives discharge energy and is combusted while being captured. 
     Because the second embodiment of combustion device  10 B has a double pipe structure having two routes of flow channels, combustion device  10 B has a flow channel which introduces particulate matters from both the upstream side and the downstream side of cylindrical metal fiber mesh anode  233 . Therefore, the particulate matters can be deposited with economy on metal fiber mesh  233  along the longitudinal direction of cylindrical mesh anode  233 , and provided with discharge energy and combusted. 
     Since power source unit  4  is the same as in the first embodiment, the description thereof is omitted. 
     As described above, in the second embodiment of combustion device for combusting particulate matters  10 B, particulate matter  6  in the gas flow has negative space charge  222  gathered around planar mesh anode  221 . Particulate matter  6 ′ having negative space charge  222  is introduced into silent discharge area A 2  extending in the longitudinal direction of pipe  100  by plate-like flow channel control member  237 , attracted by Coulomb force of silent discharge area A 2  and captured by cylindrical mesh anode  233  which constitutes silent discharge area A 2 , whereby the retention time at silent discharge area A 2  is increased. As a result, the particulate matter obtains much discharge energy and can be efficiently combusted. 
     Third Embodiment 
     As shown in  FIG. 8 , the third embodiment of combustion device  10 C for combusting particulate matters is configured so that the deposition of particulate matters  6 ′, which are included in particulate matters and have negative charge, on cathode  331  is increased, and then, combustion effect is improved, based on the repelling effect that particulate matters  6 ′ having negative charge are electrostatically repelled by planar metal fiber mesh cathode  331  provided on the downstream side, and the trapping effect of planar metal fiber mesh which constitutes cathode  331 . Specifically, as shown in  FIG. 8 , combustion device  10 C has: introduction portion  8 , charging unit  31 , electric discharge unit  35 , discharge portion  9  and power source unit  4  in the order mentioned toward the downstream side. In the example in  FIG. 8 , charging unit  31  is provided on introduction portion  8  and electric discharge unit  35  is provided in electrically insulating quadrangular prism pipe  100 . 
     In the same manner as in the first embodiment, introduction portion  8  is connected to exhaust port  2  of internal combustion engine  1 , and particulate matter-containing gas  5  discharged from exhaust port  2  is introduced into introduction portion  8 . Introduction portion  8  is formed by pipe  301  which has a smaller diameter than that of insulation pipe  100 , and is connected to the upstream side of insulation pipe  100 . On the other hand, in the same manner as in the first embodiment, discharge portion  9  is also connected to insulation pipe  100  and discharges combusted gas  151 . Discharge portion  9  is formed by pipe  341  having a diameter smaller than that of insulation pipe  100 , and is connected to the downstream side of electrically insulating quadrangular prism pipe  100 . The connection configurations of pipes  301 ,  341  to electrically insulating quadrangular prism pipe  100  are not limited. 
     The term “upstream side” herein refers to the side of engine  1  as shown in  FIG. 1 , and the term “downstream side” herein refers to the side of muffler  3  as shown in  FIG. 1 . Like ceramic pipe, both pipes  301 ,  341  preferably have electrical insulating properties and heat resistance. Introduction portion  8  is not provided with a gas flow conversion member shown in  FIG. 3 ,  FIG. 4  and  FIG. 7 . 
     On the downstream side of introduction portion  8 , planar mesh anode  321  as charging unit  31  is provided orthogonal to the flow channel of particulate matter-containing gas  5 . Planar mesh anode  321  is attached to the inner surface of pipe  301  by an attachment which is not illustrated in the figure. 
     In the same manner as in the first and the second embodiment, planar mesh anode  321  is a member which negatively-charge all or part of particulate matter  6  included in particulate matter-containing gas  5  by bringing particulate matter-containing gas  5  into contact with. For this reason, a positive voltage is preferably applied to planar mesh anode  321  from power source unit  4 . Since negative space charge (negative charge)  322  gathers to planar mesh anode  321  on which a positive voltage is applied, part of particulate matter  6  included in particulate matter-containing gas  5  which passes through planar mesh anode  221  has negative charge  322 . Namely, particulate matter  6  is negatively-charged by passing through planar mesh anode  221 , and flows to the downstream side. 
     Planar mesh anode  321  may have a mesh structure which has, for example, openings through which particulate matter  6  of 2 μm can freely pass. The material of planar mesh anode  321  is not limited, and preferably a heat resistant metal mesh. For example, a tungsten mesh or a stainless mesh having a wire diameter of 0.4 mm and 20 mesh/inch can be exemplified, but not limited thereto. The distance between this anode  321  and cathode  331  provided on the downstream side of anode  321  is not limited, and usually, may be in a range of 10 mm to 100 mm. 
     As shown in  FIG. 8 , electric discharge unit  35  in the third embodiment is provided in electrically insulating quadrangular prism pipe (square prism pipe)  100  which is connected to introduction portion  8 . Electric discharge unit  35  has: planar metal fiber mesh cathode  331  provided orthogonal to a flow channel in electrically insulating quadrangular prism pipe  100 ; and dielectric covered anode  330  provided so that silent discharge area A 3  is spaced from planar metal fiber mesh cathode  331  at predetermined gap not particularly limited, but, for example, 0.5 mm to 3 mm), and faces to planar metal fiber mesh cathode  331 . Instead of dielectric covered anode  330 , a metal mesh which is covered with dielectric may be used. By this electric discharge unit  35 , particulate matters  6 ′, on all or part of which has negative charge  322 , are introduced into silent discharge area A 3  which is generated between the device and dielectric covered anode  330 , and the deposited particulate can be combusted. 
     As shown in  FIG. 8  and  FIG. 9 , dielectric covered anode  330  is a complex formed by rod anode  332  and dielectric  333  which covers rod anode  332 . In the illustrated example, rod dielectric covered anodes  330  are arrayed in a reed shape at regular intervals (for example, at a pitch of 2 to 6 mm and a gap of 0.5 mm to 3 mm) so that each of rod dielectric covered anodes  330  spaced from planar metal fiber mesh cathode  331  at predetermined fixed distance. All dielectric covered anodes  330  are electrically connected. Particulate matter  6 ′ on gas flow easily passes through reed-shaped dielectric covered anodes  330 . Instead of a dielectric covered anode, a dielectric covered mesh anode may be used. 
     Rod anode  332  which constitutes dielectric covered anodes  330  is preferably a heat resistant metal. For example, a tungsten rod or a stainless rod is preferably used, but not limited thereto. Rod anode  332  having a diameter of about 1 mm can be exemplified. A dielectric covered mesh anode having a ceramic covered wire diameter of 2 mm and a metal wire diameter of 0.4 mm, and having about 10 mesh/inch can be exemplified. 
     Examples of dielectric  333  which covers rod anode  332  include ceramics. Covering on rod anode  332  can be performed by, for example, sputtering. Here, although rod anode  332  is described to be covered, rod anode  332  may be configured to be inserted into a ceramic pipe by using the ceramic pipe as dielectric  333 . 
     Planar metal fiber mesh cathode  331  is preferably heat resistant metal mesh (for example, wire diameter: 20 μm, porosity: 83%, thickness: 1.3 mm). For example, a tungsten mesh or a tungsten alloy mesh is preferably used, but not limited thereto. The openings of the mesh may have such a size that, for example, particulate matter  6 ′ of 0.1 μm does not easily pass the mesh and the mesh can capture. As illustrated, planar metal fiber mesh cathode  331  is held by retention member  336  of electrically insulating quadrangular prism pipe  100 . 
     Since this planar metal fiber mesh cathode  331  can capture particulate matter  6 ′, particulate matter  6 ′ is provided with sufficient discharge energy while particulate matter  6 ′ introduced into silent discharge area A 3  is captured by the mesh structure. As a result, efficient combustion can be realized. After the combustion, particulate matter  6 ′ becomes combustion gas  350  and passes through the mesh and is discharged from discharge portion  9  as exhaust gas  151 . 
     Namely, negatively charged particulate matter  6 ′ in the particulates which pass through dielectric covered anode  330  is electrostatically attracted to dielectric covered anode  330 , and passes there at a reduced speed to introduce into silent discharge area A 3 . Since particulate matter  6 ′ which has introduced into silent discharge area A 3  is electrostatically repelled by planar metal fiber mesh cathode  331 , the speed of particulate matter  6 ′ is further reduced and the deposition effect to the mesh is increased. Further, since planar metal fiber mesh cathode  331  is formed by a mesh which does not allow particulate matter  6 ′ to pass through irrelative of electrification, particulate matter  6 ′ is deposited on the mesh. As a result, charged particulate matters and non-charged particulate matters are deposited on the surface of the mesh, receive much discharge energy and can be efficiently combusted. 
     Since power source unit  4  is the same as in the first and the second embodiment, the description thereof is omitted. 
     As described above, in the third embodiment of combustion device  10 C for combusting particulate matters, the particulate is deposited on the mesh by trapping effect of planar metal fiber mesh, and further, part of particulate matter  6 ′ in the gas flow has negative space charge  322  gathered around planar mesh anode  321 . Particulate matter  6 ′ having negative space charge  322  proceeds with maintaining the negatively-charged state, passes through dielectric covered anode  330  to be introduced into silent discharge area A 3 , and repelled by the electrostatic force of silent discharge area A 3 . Particulate matter  6 ′ is deposited on planar metal fiber mesh cathode  331  which constitutes silent discharge area A 3  by these two effects. As a result, particulate matter  6 ′ obtains much discharge energy and can be efficiently combusted. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     
         
           1  Internal combustion engine 
           2  Exhaust port 
           3  Muffler 
           4  power source unit 
           5  particulate matter-containing gas 
           6  Particulate matter 
           6 ′ Particulate matter having negative space charge 
           8  Introduction portion 
           9  Discharge portion 
           10  Combustion device for combusting particulate matters 
           10 A Combustion device in the first embodiment 
           10 B Combustion device in the second embodiment 
           10 C Combustion device in the third embodiment 
           11 , 21 , 31  Charging unit 
           15 , 25 , 35  Electric discharge unit 
         A 1 , A 2 , A 3  Silent discharge area 
           100  insulation pipe (circular pipe, insulating quadrangular prism pipe, ceramic insulation pipe) 
           101 ,  101 A,  101 B Gas flow conversion member 
           102  Inflow ports 
           103  Outflow port 
           104  Flow channel 
           105  Propeller shaft 
           106  Blade 
           107  Spiral flow 
           121  Ring anode 
           122  Negative space charge 
           124  Supporting member 
           125  Ring member 
           131  Cylindrical cathode 
           132  Cylindrical dielectric 
           133  Cylindrical metal fiber mesh anode 
           134  Insulation pipes 
           135  Particulate matter in combustion 
           141  High voltage and high frequency generator 
           142  Power source 
           151  Combusted gas 
           201  Pipe 
           221  Planar mesh anode 
           222  Negative space charge 
           233  Cylindrical metal fiber mesh anode 
           234  Cylindrical dielectric (ceramic pipe) 
           235  Cylindrical cathode 
           236  Supporting bolts 
           237  Circular plate-like flow channel control member 
           238  Pillar 
           241  Insulation pipe 
           242  Coaxial ring 
           243  Flow channel 
           244  End portion 
           250  Combusted gas 
           301  Pipe 
           321  Planar mesh anode 
           322  Negative space charge 
           330  Dielectric covered anode 
           331  Planar metal fiber mesh cathode 
           332  Rod anode 
           333  Dielectric 
           335  Deposited Particulate matter 
           336  Retention member holding cathode 
           341  Pipe 
           350  Combusted gas