Plasma generator and method for producing radical, and cleaning and purifying apparatus and small-sized electrical appliance using the same

A plasma generator 1 includes a first electrode 12 provided in a gas storage section 5, and a second electrode 13 provided in such a manner that at least a portion coupled with the first electrode 12 comes into contact with a liquid 17 in a liquid storage section 4. Electrical discharge is caused between the first electrode 12 and the second electrode 13 so that plasma is produced in a gas region in the liquid 17 in the liquid storage section 4, and hydroxyl radical is produced from water contained in the liquid 17 and oxygen contained in the gas.

RELATED APPLICATIONS

This application is the U.S. National Phase under 35 U.S.C. §371 of International Application No. PCT/JP2011/063455, filed on Jun. 13, 2011, which in turn claims the benefit of Japanese Application No. 2010-163658, filed on Jul. 21, 2010, and Japanese Application No. 2011-024937, filed on Feb. 8, 2011, the disclosures of which Applications are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a plasma generator and a method for producing a radical, and a cleaning and purifying apparatus and a small-sized electrical appliance using the same.

BACKGROUND ART

There have been known methods to produce a radical and the like in gas bubbles contained in a liquid by causing electrical discharge in the liquid so as to reform the liquid (for example, refer to Patent Document 1).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

However, electrical resistance in the liquid is significantly changed because of the components contained in various types of impurities contained in the liquid to be treated. Therefore, the conventional methods described above by use of the electrical discharge in the liquid cannot produce plasma stably since the electrical discharge might be caused unequally even if a predetermined voltage was applied to the electrodes. In other words, the amount of the radical and the like produced, might vary when using the conventional methods described above.

It is an object of the present invention to obtain a plasma generator capable of producing a radical quite stably and a method for producing the radical, and a cleaning and purifying apparatus and a small-sized electrical appliance using the same.

A plasma generator according to the present invention includes: a liquid storage section that stores a liquid containing water; a gas storage section that stores a gas; a partition provided with a gas passage to introduce the gas in the gas storage section into the liquid storage section and separating the liquid storage section from the gas storage section; a first electrode provided in the gas storage section; a second electrode separated from the first electrode and provided in such a manner that at least a portion coupled with the first electrode comes into contact with the liquid in the liquid storage section; a gas supply unit that supplies a gas containing oxygen to the gas storage section so that the gas in the gas storage section is delivered under pressure into the liquid storage section via the gas passage; and a plasma power source that applies a predetermined voltage between the first electrode and the second electrode to cause electrical discharge between the first electrode and the second electrode, thereby converting the gas introduced into the gas storage section into plasma.

A method for producing a radical of the present invention includes: separating a liquid storage section that stores a liquid containing water from a gas storage section that stores a gas by a partition provided with a gas passage that allows the gas to flow therethrough, and supplying a gas containing oxygen to the gas storage section so as to deliver the gas in the gas storage section under pressure to the liquid storage section via the gas passage; developing gas bubbles containing oxygen at an opening end of the gas passage in the liquid storage section; and generating plasma in a gas region in the liquid in the liquid storage section, thereby producing hydroxyl radical from the water contained in the liquid and the oxygen contained in the gas.

A cleaning and purifying apparatus of the present invention includes: the plasma generator described above; a gas introduction passage fixed to the gas storage section to supply a gas to the gas storage section; a liquid introduction passage for introducing a liquid to the liquid storage section, and a liquid discharge passage for discharging the liquid in the liquid storage section, the liquid introduction passage and the liquid discharge passage being fixed to the liquid storage section; and a function to supply the gas from the gas introduction passage to deliver the gas in the gas storage section under pressure to the liquid storage section via the gas passage so as to release gas bubbles containing hydroxyl radical into the liquid.

A small-sized appliance of the present invention includes the plasma generator described above or the cleaning and purifying apparatus described above.

In the plasma generator according to the present invention, the first electrode is provided in the gas storage section, and the second electrode is provided in such a manner that at least the portion coupled with the first electrode comes into contact with the liquid in the liquid storage section.

In the method for producing the radical according to the present invention, the electrical discharge is caused between the first electrode and the second electrode, so that the plasma is produced in the gas region in the liquid in the liquid storage section, and the hydroxyl radical is produced from water contained in the liquid and oxygen contained in the gas.

According to the configuration and the method described above, since the electrical discharge can be caused between the first electrode and the second electrode without being influenced largely by the electrical resistance of the liquid, the gas can be converted into the plasma more reliably and accordingly, it is possible to produce a large amount of the radical more stably.

Accordingly, it is possible to obtain the cleaning and purifying apparatus and the small-sized electrical appliance capable of producing the radical, quite stably by providing the plasma generator described above in the cleaning and purifying apparatus and the small electrical appliance.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments according to the present invention will be explained with reference to the drawings. Note that identical elements are included in the respective embodiments described below. Therefore, the identical elements are indicated by the common reference numerals, and the overlapping explanations thereof are not repeated.

First Embodiment

A plasma generator1according to the present embodiment includes a case member2formed approximately in a cylindrical shape. Note that the case member is not limited to the cylindrical shape, and may be formed in a prism.

As shown inFIG. 1, a ceramic member3is provided inside the case member2to divide the case member2into an upper area and a lower area.

In the present embodiment, the upper area in the inner space of the case member2divided by the ceramic member3serves as a liquid storage section4to store a liquid17containing water, and the lower area serves as a gas storage section5to store a gas.

As described above, according to the present embodiment, the ceramic member3serves as a partition to separate the liquid storage section4from the gas storage section5.

A ring-shaped sealing member6is attached along the periphery of the liquid storage section4to seal a gap between the case member2and the ceramic member3. Accordingly, the liquid17in the liquid storage section4is prevented from leaking from the gap between the case member2and the ceramic member3into the gas storage section5.

A liquid inlet7is provided on an upper wall (a wall on the liquid storage section4side)2aof the case member2to introduce the liquid17into the liquid storage section4. In addition, a liquid outlet8is provided on the upper wall2ato discharge the liquid17introduced into the liquid storage section4to the outside.

A gas inlet9is provided at the bottom of a side wall2bof the case member2so that the gas storage section5communicates with the outside. A pipe (a gas introduction passage)10is inserted into the gas inlet9. The gas storage section5and a gas supply unit11are connected to each other via the pipe10. In the present embodiment, a gas containing at least oxygen (O2) is supplied to the gas storage section5from the gas supply unit11.

The ceramic member3is provided with a gas passage3a, through which the gas introduced from the gas supply unit11into the gas storage section5is delivered to the liquid storage section4.

Thus, the gas supply unit11according to the present embodiment functions to supply the gas containing at least oxygen to the gas storage section5so that the gas in the gas storage section5is delivered under pressure to the liquid storage section4via the gas passage3a.

In the present embodiment, a hole diameter of the gas passage3ais set approximately in a range from 1 μm to 10 μm so as to be sufficiently small to prevent the liquid17stored in the liquid storage section4from leaking from the gas passage3ainto the gas storage section5.

The plasma generator1includes a first electrode12provided in the gas storage section5, and a second electrode13separated from the first electrode12and provided in such a manner that at least a portion coupled with the first electrode12(a surface of the second electrode13arranged to generate electrical discharge to a surface of the first electrode12) comes into contact with the liquid17in the liquid storage section4.

In particular, the doughnut-shaped first electrode12and the doughnut-shaped second electrode13are provided in the gas storage section5and in the liquid storage section4, respectively.

As shown inFIG. 1, the doughnut-shaped first electrode12is provided on a surface3bof the ceramic member3on the gas storage section5side, and is positioned so as to have its center located on the gas passage3a. The surface of the first electrode12is covered with a dielectric material (not shown in the figure).

The second electrode13is provided in the liquid storage section4in such a manner that at least the portion coupled with the first electrode12(the surface of the second electrode13arranged to generate electrical discharge to a surface of the first electrode12) comes into contact with the liquid17in the liquid storage section4. The second electrode13is also positioned so as to have its center located on the gas passage3a. That is, the first electrode12and the second electrode13are arranged in a concentric pattern.

In the plasma generator1according to the present embodiment, the doughnut-shaped first electrode12is provided in the gas storage section5so that the first electrode12is prevented from coming into contact with the liquid17introduced into the liquid storage section4.

In contrast, the doughnut-shaped second electrode13is provided in the liquid storage section4in such a manner that at least the portion coupled with the first electrode12(the surface of the second electrode13arranged to generate electrical discharge to a surface of the first electrode12) comes into contact with the liquid17introduced into the liquid storage section4.

The first electrode12and the second electrode13are electrically connected to a plasma power source15via leads14, respectively (refer toFIG. 1), so that a predetermined voltage is applied between the first electrode12and the second electrode13.

In the present embodiment, as shown inFIG. 1andFIG. 2, the predetermined voltage is applied between the first electrode12and the second electrode13while the second electrode13is grounded.

Next, a performance of the plasma generator1and a method for producing hydroxyl radical are explained.

First, a gas containing oxygen is supplied to the gas storage section5so that the gas in the gas storage section5is delivered under pressure to the liquid storage section4via the gas passage3a(a step of supplying a gas).

In the present embodiment, as shown inFIG. 1, the gas based on air and containing oxygen (a flow rate is approximately from 0.01 L/min to 1.0 L/min (from 10 cc/min to 1000 cc/min)) is delivered from the gas supply unit11to the gas storage section5via the pipe10. In this case, the pressure used to deliver the gas is set approximately in a range from 0.0098 MPa to 0.49 MPa (from 0.1 kgf/cm2 to 5 kgf/cm2).

As described above, the gas supply unit11functions to supply the gas (air) in the atmosphere. Here, the flow rate of the gas supplied is controlled by a flow rate controller provided in the gas supply unit11. Alternatively, the gas supply unit11may function to supply several types of gas (for example, gases having different oxygen concentrations) in addition to the gas in the atmosphere, and may be provided with a gas type regulator to selectively supply one of or some of the several types of gas.

When the gas is supplied to the gas storage section5, the pressure in the gas storage section5is changed approximately to a range from 0.11 MPa to 0.59 MPa (from 1.1 kgf/cm2 to 6 kgf/cm2) due to the increased pressure (in addition to the atmospheric pressure), whereby the gas storage section5is in a state of a positive pressure. Due to the gas storage section5being under the positive pressure, a flow of the gas from the gas storage section5toward the liquid storage section4through the gas passage3ais generated. Even when the gas storage section5is under the positive pressure, the liquid17stored in the liquid storage section4is prevented from leaking into the gas storage section5through the gas passage3a.

When the gas containing oxygen is supplied to the gas storage section5as described above, as shown inFIG. 3, gas bubbles16containing oxygen are developed at an opening end3cof the gas passage3aon the liquid storage section4side (the upper side inFIG. 1) (a step of developing gas bubbles).

Then, a predetermined voltage is applied to the first electrode12and the second electrode13by the plasma power source15. The voltage is preferably capable of glow discharge under atmospheric pressure (power: approximately from 10 W to 100 W). In this case, it is preferable to provide a voltage controller in the plasma power source15to control the voltage applied between the first electrode12and the second electrode13.

Once the predetermined voltage is applied to the first electrode12and the second electrode13, electrical discharge is caused between the first electrode12and the second electrode13in a gas atmosphere under atmospheric pressure or higher. Note that a method for producing plasma under atmospheric pressure has been reported in, for example, Document A (Satiko Okazaki, “Atmospheric Pressure Glow Discharge Plasma and Its Applications”, Review Speech: 20th JSPF Annual Meeting).

Due to the electrical discharge, plasma is produced in a gas region in the liquid17in the liquid storage section4, and ozone and hydroxyl radical are produced from water contained in the liquid or oxygen contained in the gas (a step of producing hydroxyl radical).

According to the present embodiment, the plasma is generated by a potential difference caused in the gas inside the gas bubbles16(the gas adjacent to a gas-liquid boundary in the liquid17in the liquid storage section4). Since the potential difference is caused adjacent to the gas-liquid boundary (adjacent to the opening end3cof the gas passage3afacing the liquid17) where the hydroxyl radical is easily produced, it is possible to produce a larger amount of the ozone and hydroxyl radical. Note that, in the present embodiment, it is possible to produce the ozone and hydroxyl radical even in the gas bubbles16delivered into the liquid storage section4in addition to the gas bubbles16around the opening end3cof the gas passage3afacing the liquid17.

The ozone and hydroxyl radical produced as described above are delivered to the liquid storage section4as a result of the gas flow described above.

According to the present embodiment, the gas bubbles16containing the hydroxyl radical and the like are separated from the ceramic member (the partition)3and then released into the liquid17by the flow of the liquid17in the liquid storage section4(a step of releasing gas bubbles).

In particular, the flow of the liquid17is generated in the liquid storage section4where the gas bubbles16are developed due to the introduction of the liquid17(refer to an arrow18inFIG. 3andFIG. 4). As shown inFIG. 4, when the liquid17flowing in the direction of the arrow18hits the gas bubbles16being developed, the gas bubbles16are subjected to a separation force because of the flow of the liquid17and thereby released into the liquid17from the opening end3c.

Since the gas bubbles16released into the liquid17are fine gas bubbles, the released gas bubbles16are dispersed in the liquid17in all directions without being emitted immediately into the atmosphere. Part of the dispersed fine gas bubbles16is easily dissolved in the liquid17. At this point, the ozone contained in the gas bubbles16is dissolved into the liquid17and as a result, an ozone concentration in the liquid17is immediately increased.

According to Document B (Masayoshi Takahashi, “Improvement in Aquatic Environment by Microbubbles and Nanobubbles”; Aquanet, 2004. 6), it is reported that the fine gas bubbles16containing the ozone and several types of radicals generally tend to be negatively-charged. Therefore, part of the gas bubbles16is easily adsorbed by materials such as organic substances, oil and fat substances, dyes, proteins and bacteria (not shown in the figures) contained in the liquid17. The organic substances and the like in the liquid17are resolved by the ozone or several types of radicals dissolved in the liquid17, or by the ozone or several types of radicals contained in the gas bubbles16adsorbed by the organic substances and the like.

For example, the hydroxyl radical has relatively high energy of approximately 120 kcal/mol. Such energy exceeds bond energy (up to 100 kcal/mol) of a double bond between nitrogen atoms (N=N), a double bond between carbon atoms (C=C), a double bond between a nitrogen atom and a carbon atom (N=C) or the like. Therefore, the organic substances produced by bonding of nitrogen and/or carbon are resolved since the bonding in the organic substances is easily broken by the hydroxyl radical. Here, the ozone and hydroxyl radical contributing to such a resolution of the organic substances are environmentally-friendly substances since the ozone and hydroxyl radical are not persistent (unlike chlorine and the like) but disappear with time.

As explained above, the plasma generator1according to the present embodiment is provided with the first electrode12in the gas storage section5, and provided with the second electrode13in such a manner that at least the portion coupled with the first electrode12(the surface of the second electrode13arranged to generate electrical discharge to a surface of the first electrode12) comes into contact with the liquid17in the liquid storage section4.

The plasma is produced in the gas region inside the liquid17in the liquid storage section4by causing the electrical discharge between the surface of the first electrode12coming into contact with the gas and the surface of the second electrode13coming into contact with the liquid, thereby producing the hydroxyl radical from water contained in the liquid17and oxygen contained in the gas.

According to the configuration and the method described above, the electrical discharge can be caused between the first electrode12and the second electrode13without being influenced largely by the electrical resistance of the liquid17and therefore, the gas can be converted into plasma more reliably. Accordingly, it is possible to produce a large amount of the ozone and radical more stably.

According to the present embodiment, the predetermined voltage is applied between the first electrode12and the second electrode13while the second electrode13is grounded. Therefore, even in the case where a user accidentally touches the liquid or the second electrode, it is possible to protect the user from electrical shock.

Thus, the safety in the plasma generator according to the present embodiment can be further improved.

According to the present embodiment, the liquid17is introduced into the liquid storage section4, and the first electrode12for producing the plasma is provided in the gas storage section5that is defined by the ceramic member3. Therefore, the first electrode12does not come into contact with the liquid17at all so as not to be influenced by the electrical resistance of the liquid17. As a result, it is possible to cause the electrical discharge between the first electrode12and the second electrode13stably. Further, it is possible to produce the ozone and hydroxyl radical from water and oxygen stably since the gas containing oxygen introduced into the gas storage section5is converted into plasma reliably.

According to the present embodiment, the gas containing oxygen is introduced into the gas storage section5, whereby the gas storage section5is in the state of the positive pressure, and the flow of the gas from the gas storage section5toward the liquid storage section4through the gas passage3ais generated. The ozone and hydroxyl radical are produced inside the gas bubbles16developed at the opening end3cof the gas passage3cfacing the liquid17in association with the gas flow. The gas bubbles16developed to a particular size are separated from the opening end3cby the flow of the liquid17and then released into the liquid17.

Namely, in the present embodiment, the ozone and hydroxyl radical are produced in the gas inside the gas bubbles16(the gas adjacent to the gas-liquid boundary in the liquid17in the liquid storage section4). The gas containing the ozone and hydroxyl radical is dispersed as the fine gas bubbles16in the liquid17in all directions. Accordingly, after the production of the ozone and several types of radicals, it is possible to deliver the ozone and several types of radicals into the liquid efficiently and in quite a short time before the disappearance of the ozone and several types of radicals.

Since the fine gas bubbles16containing the ozone and several types of radicals are dispersed in the liquid17in all directions, the ozone concentration in the liquid17is increased, and the gas bubbles16are adsorbed by the organic substances contained in the liquid17. As a result, it is possible to resolve the organic substances or bacteria efficiently by the ozone dissolved in the liquid17and the several types of radicals contained in the gas bubbles16adsorbed by the organic substances and the like.

Further, since the first electrode12and the second electrode13that produce the plasma are formed into a doughnut shape, the entire size of the plasma generator1excluding the plasma power source15and the gas supply unit11can be reduced. Consequently, the plasma generator1can be easily installed in existing apparatuses. In addition, it is possible to minimize a space occupied by the plasma generator1even when installing in new apparatuses.

Further, it is possible to cause the electrical discharge stably regardless of variations of the electrical resistance of the liquid17caused between the first electrode12and the second electrode13, as long as the plasma power source15is provided with the voltage controller to control the voltage applied between the first electrode12and the second electrode13.

In the case where the gas supply unit11includes the gas type regulator to regulate the type of the gas, it is possible to adjust the amount of the ozone and hydroxyl radical produced.

It is possible to supply the gas more easily if the gas supply unit11functions to supply air in the atmosphere.

Further, it is possible to produce the plasma more stably if the flow rate controller controls the flow rate of the gas supplied.

Second Embodiment

In the present embodiment, an example of a cleaning and purifying apparatus using the plasma generator1will be explained.

A cleaning and purifying apparatus20according to the present embodiment includes the plasma generator1described above as shown inFIG. 5. In the cleaning and purifying apparatus20, a pipe (a liquid introduction passage)21to introduce the treated liquid17from a cleaning treatment target section30into the liquid storage section4is connected to the liquid inlet7of the case member2that houses the ceramic member3. In addition, a pipe (a liquid discharge passage)22to deliver the liquid inside the liquid storage section4to the cleaning treatment target section30is connected to the liquid outlet8.

Next, a performance of the cleaning and purifying apparatus20is explained.

As shown inFIG. 5, a gas based on air and containing oxygen and with a predetermined flow rate is delivered from the gas supply unit11to the gas storage section5via the pipe (the gas introduction passage)10. Once the gas storage section5is shifted to a state of a positive pressure, a flow of the gas from the gas storage section5toward the liquid storage section4through the gas passage3cis generated.

At this point, the treated liquid17from the cleaning treatment target section30is introduced into the liquid storage section4from the pipe (the liquid introduction passage)21through the liquid inlet7.

Then, a predetermined voltage is applied between the first electrode12and the second electrode13while the second electrode13is grounded so that electrical discharge is caused between the first electrode12and the second electrode13. Due to the electrical discharge (the discharge caused between the surface of the first electrode12coming into contact with the gas and the surface of the second electrode13coming into contact with the liquid), plasma is produced in the gas region in the liquid17in the liquid storage section4, and ozone and hydroxyl radical are produced from water contained in the liquid17and oxygen contained in the gas (refer toFIG. 4).

The produced ozone and several types of radicals are delivered to the liquid storage section4along with the gas flow described above. At this point, the gas bubbles being developed are separated from the opening end3cby the flow of the liquid17as described above, and then released as the fine gas bubbles16into the liquid from the opening end3c.

The fine gas bubbles16released into the liquid are dispersed in the liquid in all directions. Part of the dispersed fine gas bubbles16is easily dissolved in the liquid17together with the ozone and hydroxyl radical contained in the gas bubbles16, and the ozone concentration is thus increased. In addition, part of the gas bubbles16in a state of containing the ozone and hydroxyl radical is easily adsorbed by organic substances and the like contained in the liquid17. Further, fine organic substances are adsorbed by part of the gas bubbles16.

As a result, the organic substances in the liquid17are resolved efficiently by the ozone or radical dissolved in the liquid17or by the ozone or radical contained in the gas bubbles16adsorbed by the organic substances. Then, the cleaned liquid17in which the organic substances are resolved returns to the cleaning treatment target section30from the liquid outlet8through the pipe (the liquid discharge passage)22so as to be reused.

The cleaning and purifying apparatus20described above was exemplified by a usage mode (usage mode A) in which the liquid is cleaned and purified inside the case member2. Alternatively, another usage mode (usage mode B) in which the liquid17containing the fine gas bubbles dispersed therein is supplied to a particular device as a cleaning liquid may be applicable.

In the latter case, the cleaning and purifying apparatus20operates as follows.

First, the fine gas bubbles16containing the ozone and hydroxyl radical are dispersed in the liquid17introduced into the case member2, and the ozone and hydroxyl radical contained in the fine gas bubbles16are dissolved in the liquid17. At this point, fine organic substances are adsorbed by part of the gas bubbles16.

Then, the liquid17is supplied as a cleaning liquid to the cleaning treatment target section30. In the cleaning treatment target section30, the organic substances and the like are efficiently resolved by the ozone or radical dissolved in the liquid17, or by the ozone or radical contained in the gas bubbles16adsorbed by the organic substances.

In the case of using the cleaning and purifying apparatus in the usage mode A, the cleaning and purifying apparatus may be used for the purification of various types of liquids such as warm water from a bathtub, rainwater, foul water and sewage water. In the case of using the cleaning and purifying apparatus in the usage mode B, the liquid17may be applied to water as a purifying liquid used for, for example, various types of appliances such as a washing machine and a dishwasher, health appliances such as a mouthwashing device, and sanitary appliances such as a lavatory basin. In addition to these appliances, a wide variety of industrial applications such as washing of food and cleaning of industrial products in manufacturing processes may be possible.

As explained above, in the present embodiment, the cleaning and purifying apparatus20is provided with the plasma generator1. Accordingly, it is possible to obtain the cleaning and purifying apparatus capable of producing the radical quite stably.

Third Embodiment

In the present embodiment, an example of a small-sized appliance using the plasma generator1will be explained with reference toFIGS. 6 to 8. Hereinafter, a cleaning and purifying apparatus for cleaning a head unit of an electric shaver as a hair removing device will be exemplified.

A cleaning and purifying apparatus40as a small-sized appliance shown inFIGS. 6 to 8cleans a head unit51of an electric shaver50which is a type of hair removing device. The cleaning and purifying apparatus40is used in the usage mode B described above. In this case, the head unit51of the electric shaver50corresponds to the cleaning treatment target section30.

As shown inFIGS. 6 to 8, the cleaning and purifying apparatus40includes a case41having an opening41athrough which the electric shaver50with the head unit51directed downward is inserted, and a receiving plate42that receives the head unit51inserted via the opening41a.

In addition, the cleaning and purifying apparatus40includes a tank43for storing a liquid, an overflow section44that communicates with the receiving plate42, and a pump45that cyclically supplies the liquid stored in the tank43to the liquid inlet7. Further, the cleaning and purifying apparatus40includes a cartridge46having a filter46afor filtration of the liquid, an opening and closing valve47that controls an airtight state inside the tank43, and a circulation path in which the liquid is circulated.

The circulation path includes the pipe (the liquid introduction passage)21for introducing the liquid stored in the tank43into the liquid inlet7, the pipe (the liquid discharge passage)22for introducing the liquid discharged from the liquid outlet8into the receiving plate42, a path23(a discharge passage) for introducing the liquid discharged from the receiving plate42into the cartridge46, a path24for introducing the liquid discharged from the overflow section44into the cartridge46, a path25for introducing the liquid discharged from the cartridge46into the pump45, and a path26for introducing the liquid delivered from the pump45into the tank43. The opening and closing valve47is connected to the tank43via an airtight path27. The following is an explanation with regard to the respective components.

The case41is provided with a stand41bthat comes into contact with a grip52of the electric shaver50at the back side thereof to hold the electric shaver50inserted from the opening41ain contact with the receiving plate42. As shown inFIG. 6, the stand41bis provided, on the front surface thereof, with contact members41cthat detect the loading of the electric shaver50when a terminal52aprovided on the back surface of the grip52comes into contact with the contact members41c. In addition to such a detecting function, the electric shaver50has a function to output several control signals and drive power.

The case41houses a fan48in a front and upper portion for drying the head unit51after cleaning. The case41is provided, on the front side thereof, with a ventilation window41dfor the fan48, an operation button41eto start a cleaning operation, and a lamp41fto indicate an operation state. The case41is provided with the tank43on the back side having connecting ports41g,41hand41icommunicating with each port43a,43band43cof the tank43. The connecting port41gis connected to the pipe (the liquid introduction passage)21, the connecting port41his connected to the path26, and the connecting port41iis connected to the airtight path27.

The receiving plate42is formed into a concave shape along the shape of the head unit51. The plasma generator1is provided on the back surface of a bottom wall of the receiving plate42. The cleaning and purifying apparatus40may be provided with a position adjuster that adjusts the position of the plasma generator1. For example, the receiving plate42may be provided, on the back side of the bottom wall, with an arm member to which the plasma generator1is fixed. The plasma generator1is fixed such that it moves freely so that the position adjuster can adjust and maintain the plasma generator1in a horizontal position. Accordingly, it is possible to constantly keep the plasma generator1in the horizontal position and thereby produce the plasma more stably.

The plasma generator1includes the liquid inlet7connected to the pipe (the liquid introduction passage)21, and the liquid outlet8connected to the pipe (the liquid discharge passage)22. The bottom wall of the receiving plate42is provided with a supply port41jconnected to the pipe (the liquid discharge passage)22and a discharge port41kconnected to the path23.

Heaters49are provided on the back side of the bottom wall of the receiving plate42(refer toFIG. 8). The heaters49dry the head unit51in association with the fan48.

The overflow section44is provided on the front side of the receiving plate42. The receiving plate42and the overflow section44are integrally formed in the present embodiment. An inlet of the overflow section44is connected to the receiving plate42, and an outlet of the overflow section44is connected to the path24. The path24connects the outlet of the overflow section44to the cartridge46via a junction port42aprovided on the rear side of the receiving plate42.

The tank43is provided, on the front surface thereof, with the outflow port43a, the inflow port43b, and the ventilation port43cfor releasing the tank43from the airtight state. The ventilation port43copens and closes to control liquid discharge from the outflow port43a. The tank43is detachably provided on the back side of the case41. In the state of being attached to the case41, the outflow port43ais connected to the connecting port41gto communicate with the liquid inlet7of the plasma generator1via the pipe (the liquid introduction passage)21. The inflow port43bis connected to the connecting port41hto communicate with a delivery port45aof the pump45via the path26. The ventilation port43cis connected to the connecting port41ito communicate with the opening and closing valve47via the airtight path27.

The cartridge46is formed approximately into a box shape that houses the filter46atherein, and has an inflow port46bon the upper side and an outflow port46con the front side. The cartridge46is detachably provided on the bottom and rear side of the case41. In the state of being attached to the case41, the inflow port46bis connected to the discharge port41kvia the path23(the discharge passage), and connected to the outlet of the overflow section44via the path24. The outflow port46cis connected to a suction port45bof the pump45via the path25.

According to the above-described configuration, a cleaning liquid, which is produced by dispersing the fine gas bubbles16containing the ozone and hydroxyl radical into the liquid introduced into the plasma generator1from the tank43, is supplied to the receiving plate42from the supply port41j. Namely, the produced cleaning liquid is supplied to the head unit51as the cleaning treatment target section30. Thus, it is possible to efficiently resolve the organic substances and the like attached to the head unit51by the ozone or radical dissolved in the liquid (the cleaning liquid), or by the ozone or radical contained in the gas bubbles16.

As explained above, according to the present embodiment, the cleaning and purifying apparatus (the small-sized appliance)40is provided with the plasma generator1. Accordingly, the small-sized appliance capable of producing the radical quite stably can be obtained.

It is possible to further stabilize the plasma by providing the position adjuster that adjusts the position of the plasma generator1in the cleaning and purifying apparatus20.

Modified Example of Third Embodiment

A cleaning and purifying apparatus40A as a small-sized appliance according to the present modified example also cleans the head unit51of the electric shaver50which is a type of hair removing device, and is used in the usage mode B, as in the case of the third embodiment.

The cleaning and purifying apparatus40A has approximately the same constitution as that in the third embodiment, and includes the case41having the opening41athrough which the electric shaver50with the head unit51directed downward is inserted, and the receiving plate42that receives the head unit51inserted via the opening41a(refer toFIG. 10).

In addition, the cleaning and purifying apparatus40A includes the tank43for storing a liquid, the overflow section44that communicates with the receiving plate42, and the pump45that cyclically supplies the liquid stored in the tank43to the liquid inlet7. Further, the cleaning and purifying apparatus40A includes the cartridge46having the filter46afor filtration of the liquid, the opening and closing valve47that controls the airtight state inside the tank43, and the circulation path in which the liquid is circulated.

In the modified example, the circulation path includes the pipe (the liquid introduction passage)21for introducing the liquid stored in the tank43into the receiving plate42, the path23(the liquid discharge passage) for introducing the liquid discharged from the receiving plate42into the cartridge46, the path24for introducing the liquid discharged from the overflow section44into the cartridge46, the path25for introducing the liquid discharged from the cartridge46into the pump45, and the path26for introducing the liquid delivered from the pump45into the tank43.

The receiving plate42is formed into a concave shape along the shape of the head unit51, and the bottom wall of the receiving plate42is provided with a through-hole42b(refer toFIG. 10andFIG. 11). A plasma generator1A is provided on the back surface of the bottom wall of the receiving plate42in such a manner that the liquid storage section4communicates with the inner space of the receiving plate42via the through-hole42b.

The plasma generator1A according to the modified example fundamentally has approximately the same configuration as that of the plasma generator1according to the first embodiment. That is, the plasma generator1A includes the case member2, and the ceramic member (the partition)3is provided inside the case member2to divide the case member2into an upper area and a lower area.

As shown inFIG. 9, the upper area in the inner space of the case member2divided by the ceramic member3serves as the liquid storage section4to store the liquid17containing water, and the lower area serves as the gas storage section5to store the gas.

The ring-shaped sealing member6is attached along the periphery of the liquid storage section4to seal a gap between the case member2and the ceramic member3, so as to prevent the liquid17in the liquid storage section4from leaking from the gap between the case member2and the ceramic member3into the gas storage section5.

The modified example differs from the third embodiment in that the liquid17in the liquid storage section4is not supplied to the inner space of the receiving plate42via the pipe (the liquid discharge passage)22, but the plasma generator1A is provided in such a manner that the liquid storage section4communicates with the inner space of the receiving plate42, so that the inner space of the receiving plate42also functions as the liquid storage section4of the plasma generator1A (that is, the inner space of the receiving plate42concurrently serves as the liquid storage section of the plasma generator).

Namely, the cleaning and purifying apparatus40A as the small-sized appliance according to the modified example includes the plasma generator1A, which includes the liquid storage section (the liquid storage section4and the inner space of the receiving plate42) that stores the liquid containing water, the gas storage section5that stores the gas, and the partition3provided with the gas passage to introduce the gas inside the gas storage section5into the liquid storage section (the liquid storage section4and the inner space of the receiving plate42), and separating the liquid storage section (the liquid storage section4and the inner space of the receiving plate42) from the gas storage section5.

In other words, the cleaning and purifying apparatus40A as the small-sized appliance according to the modified example includes the liquid storage section (the liquid storage section4and the inner space of the receiving plate42) that holds the head unit51as the cleaning treatment target section and stores the liquid containing water, and includes the gas storage section5. The liquid storage section (the liquid storage section4and the inner space of the receiving plate42) and the gas storage section5are defined by the partition3.

Therefore, the second electrode13in the modified example is not required to be provided inside the liquid storage section4of the plasma generator1A, but may be provided in the inner space of the receiving plate42.

Although the modified example was exemplified by the case in which the partition3is provided separately from the bottom wall of the receiving plate42, the partition3may be integrated with the bottom wall of the receiving plate42. Namely, the bottom wall of the receiving plate42may also serve as the partition3.

It is preferable to form, for example, drain grooves in the receiving plate42so as to discharge the liquid in the liquid storage4from the path23(the liquid discharge passage) more smoothly.

In the modified example, the pipe21corresponds to the liquid introduction passage of the cleaning and purifying apparatus, and the path23corresponds to the liquid discharge passage of the cleaning and purifying apparatus as described above.

Next, a performance of the cleaning and purifying apparatus40A is explained.

First, the liquid is introduced into the receiving plate42and the liquid storage section4of the plasma generator1A from the tank43via the pipe (the liquid introduction passage)21.

The gas based on air and containing oxygen and with a predetermined flow rate, is delivered from the gas supply unit11to the gas storage section5via the pipe (the gas introduction passage)10. Once the gas storage section5is shifted to a state of a positive pressure, a flow of the gas from the gas storage section5toward the liquid storage section4through the gas passage3cis generated.

Then, a predetermined voltage is applied between the first electrode12and the second electrode13while the second electrode13is grounded so that electrical discharge is caused between the first electrode12and the second electrode13. Due to the electrical discharge (the discharge caused between the surface of the first electrode12coming into contact with the gas and the surface of the second electrode13coming into contact with the liquid), plasma is produced in the gas region inside the liquid17in the liquid storage section4, and ozone and hydroxyl radical are produced from water contained in the liquid17and oxygen contained in the gas (refer toFIG. 4).

The produced ozone and several types of radicals are delivered to the liquid stored in the liquid storage section4and the receiving plate42as a result of the gas flow described above. At this point, the fine gas bubbles being developed are released as the fine gas bubbles16into the liquid from the opening end3c, and the released fine gas bubbles16are dispersed in the liquid in all directions. Namely, the liquid thus obtained is supplied to the head unit51as the cleaning treatment target section30. Thus, the organic substances attached to the head unit51can be resolved efficiently by the ozone or radical dissolved in the liquid (the cleaning liquid), or by the ozone or radical contained in the gas bubbles16. Here, the gas bubbles being developed may be separated from the opening end3cby the flow of the liquid in the liquid storage section4generated by the circulation of the liquid, so as to be released into the liquid. Alternatively, the gas bubbles16may be released naturally into the liquid by use of a phenomenon that gas bubbles are produced when passing through the small gas passage3a.

The modified example described above can also achieve the similar effects to the third embodiment.

Here, the predetermined voltage is applied between the first electrode12and the second electrode13while the second electrode13is grounded, so that a user is protected from electrical shock even if the user accidentally touches the liquid17or the second electrode13. Accordingly, it is possible to significantly increase the safety of the cleaning and purifying apparatus40a.

This configuration is effective especially in the case in which the second electrode13is provided in a non-enclosed state as in the case of the modified example.

Although the preferred embodiments of the present invention have been explained above, the present invention is not limited to the embodiments described above, and various modifications and improvements can be made within the scope of the present invention.

Although the respective embodiments were exemplified by the ceramic member as the partition provided with the gas passage, the material of the partition is not limited to the ceramic member. For example, the partition may be obtained in such a manner that an arbitrary member such as a glass plate to separate a gas from a liquid is prepared and subjected to photoengraving and etching processing so as to have fine pores having a size of approximately 1 μm to 10 μm.

The partition may be provided with plural gas passages.

The cleaning and purifying apparatus and the small-sized appliance are not particularly limited to those in the embodiments described above. For example, the present invention may be applied to, for example, a cleaning and purifying apparatus for an electrical toothbrush, a water filtration apparatus, and an apparatus for purifying water containing detergents before discharging.

The liquid storage section, the gas storage section, and the other particular specs (such as a figure, size and layout) can also be changed as necessary.

INDUSTRIAL APPLICABILITY

According to the present invention, it is possible to obtain the plasma generator capable of producing a radical quite stably, the method for producing the radical, and the cleaning and purifying apparatus and the small-sized electrical appliance using the same.