KR20070018030A - Electric discharge device and air cleaner - Google Patents

Abstract

By setting the frequency fv of the periodically varying voltage to be equal to or greater than the frequency fs of the streamer discharge, the discharge delay time generated during one streamer discharge can be shortened.

Discharge electrode, streamer discharge, frequency, discharge device, air purifier

Description

Discharge device and air purifier {ELECTRIC DISCHARGE DEVICE AND AIR CLEANER}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a discharge device for applying stream voltage to periodically discharge streamer discharge, and an air purifier having the discharge device.

Background Art Conventionally, an air purifier having a discharge device has been used as a means for decomposing and removing odor components, harmful components, etc. by plasma generated by discharge. Among these air purifiers, a streamer discharge type air purifier that generates low-temperature plasma by streamer discharge is a technique suitable for decomposition or deodorization of harmful components because high air purification efficiency is obtained at relatively low power.

The streamer discharge type air purifier includes a plurality of discharge electrodes, a counter electrode opposing the discharge electrodes, and power supply means for applying a voltage to both electrodes. In such a configuration, when voltage is applied to both electrodes by the power supply means, streamer discharge occurs between the two electrodes to generate low temperature plasma. Then, the active species (high-speed electrons, ions, radicals, other excitation molecules, etc.) generated by the generation of the low temperature plasma are contacted with harmful components or odor components in the air to be treated to decompose and remove them ( See, for example, Patent Document 1: Japanese Patent Application Laid-Open No. 2002-336689).

However, such a streamer discharge type discharge device has a high decomposition efficiency with respect to odor or harmful components, while the state of the streamer discharge (the frequency of the streamer discharge or the occurrence of the streamer discharge) is affected by various factors. It has a tendency to be sensitively influenced. For example, there is a problem that the streamer discharge is not stabilized when the discharge characteristics of each electrode are different due to the dimensional or assembly errors or the adhesion of dust between both electrodes, for example.

This point will be described with reference to FIG. 10. 10 shows discharge characteristics of the plurality of electrodes a, b, and c, respectively, in which the horizontal axis is an applied voltage V applied to these electrodes, and the vertical axis is a discharge current I flowing during discharge. And these electrodes a, b, and c generate | occur | produce a difference in discharge characteristic for the reason mentioned above. Under these conditions, if a predetermined applied voltage (for example, V1 in FIG. 10) is applied to each electrode, the voltage required for discharge is not applied to some electrodes (for example, c electrode in FIG. 10). There is a possibility that the trimmer discharge will not occur. In this way, when the streamer discharge is not performed at some electrodes, there is a problem that the amount of generation of active species such as high-speed electrons and radicals is reduced, and the air purification rate of the air purifier having the discharge device is reduced.

As a prior art that solves this problem, there is a discharge device which applies a periodically varying voltage to both electrodes by a power supply means. In this discharging device, as shown in FIG. 11, by periodically changing the voltage (for example, Vp in FIG. 11), each electrode has a predetermined voltage value (for example, V1, V2, V3 in FIG. 11). The streamer discharge is performed so that the problem of the difference in discharge characteristics described above can be solved (see Patent Document 2; Japanese Patent Application Laid-Open No. 2003-53129).

Disclosure of the Invention

Problems to be Solved by the Invention

By the way, in the discharge apparatus disclosed by patent document 1 and patent document 2, a streamer discharge generate | occur | produces in a pulse form. This will be described with reference to FIG. 5. 5 (A), (B), and (C) show step by step the movement concept of the electrons 51 and the charged particles 52 (cations) in the streamer discharge.

At the time of streamer discharge, microarc called leader 53 is generated from discharge electrode 41 toward counter electrode 42. At the tip of the leader 53, air is ionized to the electrons 51 and the charged particles 52 by a strong potential gradient. When the charged particles 52 reach the counter electrode 42 side, one time of discharge is completed.

At this time, the electrons 51 generated by ionization move toward the discharge electrode 41, and the charged particles 52 move toward the counter electrode 42 (FIG. 5A). Since the charged particles 52 generated by ionization have a relatively large mass compared to the electrons 51, the moving particles are slower in the charged particles 52 than in the electrons 51. Therefore, in one streamer discharge, the charged particles 52 temporarily remain between the two electrodes 41 and 42 (FIG. 5B). When the remaining charged particles 52 completely move to the counter electrode 42, the two electrodes 41 and 42 return to the original electric field and discharge starts again (Fig. 5 (C)). As described above, during the streamer discharge, the cycle of (A) → (B) → (C) is repeated, and the streamer discharge occurs in the pulse form due to the intermittent movement of the charged particles 52 generated in this cycle. .

In such a streamer discharge, the following problem arises in the discharge apparatus which applies the voltage which changes periodically as disclosed in patent document 2.

FIG. 6 is a graph showing a streamer discharge generation characteristic in a discharge device to which a periodically varying voltage Vp is applied in time, with the horizontal axis representing time t and the vertical axis representing applied voltage V. FIG. Here, the discharge electrode has a characteristic of performing streamer discharge when a voltage of (Vmin) or higher is applied, for example.

Under such conditions, the first streamer discharge is performed when the changing voltage Vp becomes equal to or greater than (Vmin) at t1, for example. In this streamer discharge, since the above-mentioned charged particle 52 remains between electrodes, it takes time until the charged particle 52 reaches the counter electrode 42. FIG. As a result, a predetermined discharge period Ts is required between the execution of one streamer discharge and the execution of the next streamer discharge. In this case, when a voltage that periodically changes to both electrodes 41 and 42 is applied, there is a possibility that the voltage Vp did not become higher than (Vmin) after the discharge period Ts elapsed (for example, in FIG. 6). t2). In this case, at the time t2, the next streamer discharge is not made, and at the time t3 when the voltage Vp first reaches (Vmin) or more after the discharge cycle Ts has elapsed, the next streamer discharge is made. . Therefore, the time from t2 to t3 (period indicated by the dotted arrow in Fig. 6) becomes the discharge delay time, resulting in discharge loss at both electrodes 41 and 42. As described above, in order to stably perform the streamer discharge and exhibit the high air purification efficiency, it is required to minimize the discharge loss caused by the discharge delay time.

SUMMARY OF THE INVENTION The present invention has been made in view of this point, and an object thereof is to provide a discharge device in which a voltage that is periodically varied is applied so as to reduce the discharge loss between both electrodes so that the streamer discharge can be stably executed. There is.

Means for Solving the Invention

According to the present invention, the discharge loss of the discharge device can be reduced by increasing the frequency of the voltage applied to the discharge electrode and the counter electrode.

Specifically, the first invention includes a plurality of discharge electrodes 41 and opposing electrodes 42 opposed to the discharge electrodes 41, and the voltages that periodically vary from the power supply means 45 are positive. A discharge device that performs streamer discharge between both electrodes 41 and 42 by applying to (41, 42) is assumed. The discharge device has a frequency fv of the voltage applied to the positive electrodes 41 and 42, and a frequency fs of the streamer discharge generated in a pulse form between the positive electrodes 41 and 42,

It satisfies the relation of fv≥fs. Here, the "frequency of the streamer discharge" fs is the frequency of the streamer discharge generated in the form of a pulse due to the residual of the charged particles 52 shown in FIG. will be.

In the first invention, the frequency fv of the periodically varying voltage becomes equal to or greater than the frequency fs of the streamer discharge and is applied from the power supply means 45 to the both electrodes 41 and 42. In other words, as shown in FIG. 7, the period Tv (voltage period) of the voltage which changes periodically becomes less than the discharge period Ts. When the streamer discharge is performed under such conditions, as shown in FIG. 6, for example, as compared with the case where the voltage period Tv is larger than the discharge period Ts, the discharge delay time during the streamer discharge (see FIG. 7). Dotted arrow period) can be shortened.

In the discharge device of the first invention, the second invention relates to a frequency fv [kHz] of the voltage applied to the positive electrodes 41 and 42, and a distance G between the positive electrodes 41 and 42, [mm]. When k = 40 [mm / kHz],

It satisfies the relation of fv≥k / G.

In the second invention, the voltage frequency fv that is equal to or greater than the discharge frequency fs is determined based on the distance G (gap length) between the two electrodes 41 and 42, and the voltage of the voltage frequency fv. This is applied from the power supply means 45 to both electrodes 41 and 42.

This point will be described with reference to FIG. 5. The streamer discharge occurs in the form of a pulse due to the remaining of the charged particles 52. As a result, when the distance from the charged particles 52 to the counter electrode 42, that is, the gap length G is shortened, the remaining time of the charged particles 52 is also shortened and the discharge frequency fs becomes large. On the other hand, when the gap length G becomes long, the residence time of the charged particles 52 also becomes long, and the discharge frequency fs becomes small. In this way, the discharge frequency fs of the streamer discharge is largely governed by the gap length G, and the discharge frequency fs can be estimated approximately by the gap length G.

In the present invention, the discharge frequency fs at the time of streamer discharge is estimated from the gap length G (from the experimental expression fs = k / G, (k = 40 [mm / kHz])). The voltage frequency fv is determined based on the discharge frequency fs. Therefore, the voltage frequency fv can be reliably set to be equal to or higher than the discharge frequency fs, and the discharge delay time at the time of streamer discharge can be reliably shortened.

In the third invention, in the discharge device of the first or second invention, the frequency (fv) [kHz] of the voltage applied to both electrodes (41, 42) is

It satisfies the relation of fV≥20 [kHz].

In the third invention, the voltage is applied to both electrodes 41 and 42 by the power supply means 45 at a voltage frequency fv equal to or greater than the discharge frequency fs and equal to or higher than 20 [kHz]. Since the discharge frequency fs of the streamer discharge is generally less than 20 [kHz], the voltage frequency fv should be 20 [kHz] or more, so that the voltage frequency fv can be reliably above the discharge frequency fs. Can be. Therefore, the discharge delay time (dashed arrow period in FIG. 6) at the time of streamer discharge can be shortened reliably.

In a fourth invention, in the discharge device of the first, second or third invention, the average voltage Va and the amplitude Vp-p of the voltages applied to both electrodes 41 and 42 are

It satisfies the relational expression of Vp-p ≦ 0.1 × Va.

In the fourth aspect of the present invention, a voltage that periodically fluctuates at an amplitude Vp-p of 10% or less with respect to the average voltage Va is applied from the power supply means 45 to both electrodes 41 and 42. Thereby, the fluctuation range of the voltage applied to both electrodes 41 and 42 becomes 10% or less with respect to average voltage Va. Here, the streamer discharge has a feature that sparks are more likely to occur as compared to discharge such as electrostatic precipitation. Therefore, when amplitude Vp-p is large with respect to the average voltage Va of the voltage applied, when the voltage applied to both electrodes 41 and 42 becomes high and this voltage will reach | attain the spark area | region, the positive electrode 41 There is a possibility of a spark in between.

On the other hand, in the present invention, since the fluctuation range of the voltage applied to the positive electrodes 41 and 42 is narrowed to 10% or less with respect to the average voltage Va, the voltage applied to the positive electrodes 41 and 42 becomes high and reaches the spark region. Discardment can be suppressed and this spark generation can be suppressed.

The fifth invention includes a discharge device which performs streamer discharge between the discharge electrode 41 and the counter electrode 42, and distributes the air to be processed between the electrodes 41 and 42 to clean the air to be processed. It is assumed that the air purifying device. The discharge device is the discharge device of any one of the first to fourth inventions.

In the fifth invention, the discharge device of any one of the first to fourth inventions is applied to an air purifier. The discharge delay time during streamer discharge in the air purifier can be shortened.

Effects of the Invention

According to the first invention, the voltage of the voltage frequency fv that is equal to or greater than the discharge frequency fs is applied to both electrodes 41 and 42. In each of the electrodes 41 and 42, it is possible to shorten the discharge delay time occurring at the time of streamer discharge. As a result, the discharge loss of the positive electrodes 41 and 42 can be suppressed, and the streamer discharge can be stably executed.

According to the second invention, the voltage frequency fv is determined based on the discharge frequency fs estimated by the gap length G. As a result, the voltage frequency fv can be reliably set to be equal to or higher than the discharge frequency fs, and the discharge delay time during streamer discharge can be shortened. Therefore, the discharge loss of this discharge device can be reliably suppressed.

According to the third aspect of the present invention, a voltage frequency fv equal to or higher than the discharge frequency fs and equal to or higher than 20 [kHz] is applied. As a result, the voltage frequency fv can be set to be equal to or higher than the discharge frequency (about 20 [kHz]) of the conventional streamer discharge, and the discharge delay time during the streamer discharge can be shortened.

When the voltage frequency fv is set to 20 [kHz] or more, the negative frequency corresponding to the output of this voltage becomes higher than that of the human audible region. Therefore, the noise generated in the vicinity of the power supply means 45 can be suppressed.

According to the fourth invention, the amplitude Vp-p of the periodically varying voltage is set to 10% or less with respect to the average voltage Va. As a result, the range of voltages applied to both electrodes 41 and 42 is narrowed, and it is possible to suppress that the voltages applied to both electrodes 41 and 42 reach the spark region. Therefore, spark generation can be suppressed and the stability of streamer discharge can be improved in this discharge device.

According to the fifth aspect of the present invention, by applying the discharge device of any one of the first to fourth inventions to the air purifier, it is possible to shorten the discharge delay time during streamer discharge in the air purifier. As a result, the discharge loss of the air purifier can be reduced, and stable streamer discharge can be performed. Therefore, the air purification efficiency of this air purifier can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic perspective view which shows the whole structure of the air purification apparatus which concerns on this embodiment.

2 is a configuration diagram of the inside of the discharge device according to the present embodiment as seen from above.

3 is an enlarged perspective view of a main part of the discharge device according to the present embodiment;

4 is a circuit diagram of a power supply unit of the discharge device according to the present embodiment.

5 is an explanatory view of the principle of streamer discharge.

6 is an example of a graph showing a relationship between a discharge frequency and a voltage frequency.

7 is an example of a graph showing a relationship between a discharge frequency and a voltage frequency.

8 is a simulation result verifying the effect of the relationship between the discharge frequency and the voltage frequency on the discharge delay time.

9 is a graph showing a relationship between a gap length and a discharge frequency.

10 is an explanatory diagram showing discharge characteristics of a discharge device according to the prior art.

Fig. 11 is an explanatory diagram showing discharge characteristics when a voltage that is periodically varied is applied.

Explanation of the sign

10: air purifier 40: discharge device

41: discharge electrode 42: counter electrode

45: power supply means fv: voltage frequency

fs: discharge frequency Tv: voltage cycle

Ts: discharge cycle

The present embodiment will be described with reference to FIGS. 1 to 4.

FIG. 1 is an exploded perspective view of the air purifier 10 according to the present embodiment, and FIG. 2 is a view of the inside of the air purifier 10 as viewed from above. The air purifier 10 is a household air purifier used in a general home or a small store. The air purifier 10 is a so-called streamer discharge type air purifier that generates low-temperature plasma to clean the air to be processed by streamer discharge.

The air purifier 10 has a casing 20 composed of a box-shaped casing main body 21 with one end opened and a front plate 22 mounted on the open end face thereof. Inlet 23 is formed at both sides of the casing 20 front plate 22 side. The casing main body 21 is provided with a discharge port 24 toward the rear surface of the ceiling.

In the casing 20, an air passage 25 through which the indoor air serving as the air to be processed is formed is formed from the inlet port 23 to the outlet port 24. In this air passage 25, various functional parts 30 which perform air purification sequentially from the upstream side of the air to be processed (downward in Fig. 2), and centrifugal for circulating indoor air in the air passage 25. Blower 26 is arranged.

The functional part 30 includes a prefilter 31, an ionizer 32, an electrostatic filter 33, and a catalytic filter 34 in order from the front plate 22 side. The ionizer 32 is integrally built with a discharge device 40 for generating low temperature plasma. Further, the power supply means 45 of the discharge device 40 is disposed below the casing main body 21 of the air purifying device 10.

The prefilter 31 is a filter which collects comparatively large dust contained in air. The ionizer 32 charges relatively small dust that has passed through the prefilter 31 and collects the dust into an electrostatic filter 33 disposed downstream of the ionizer 32. The ionizer 32 is composed of a plurality of ionization lines 35 and a plurality of counter electrodes 42. The plurality of ionization wires 35 are tightly stretched at equal intervals from the upper end to the lower end of the ionization part 32, and each is located on one virtual surface parallel to the electrostatic filter 33. The counter electrode 42 is composed of a long length member having a horizontal cross section in the form of an inverted-disc, and an open portion thereof is located at the rear side. The counter electrode 42 is arranged in parallel with the ionization line 35 between each ionization line 35. Each of the counter electrodes 42 is joined to each of the mesh plates 37 by an open portion.

The discharge device 40 includes a plurality of discharge electrodes 41 and a counter electrode 42 facing the discharge electrodes 41. The counter electrode 42 is shared as the counter electrode 42 of the ionizer 32, and each discharge electrode 41 is formed inside each counter electrode 42 facing the discharge electrode 41. Is placed.

Specifically, inside the counter electrode 42, as shown in FIG. 3, which is an enlarged perspective view of the discharge device 40, an electrode holding member 43 extending in the vertical direction is disposed, and the discharge electrode 41 is a fixed member. It is supported by the electrode holding member 43 via the 44. The discharge electrodes 41 are linear to rod-shaped electrodes, and the discharge electrodes 41 protruding from the fixing member 44 are disposed to be substantially parallel to the first surface 42a of the counter electrode 42. The distance (gap length) G from the distal end of the discharge electrode 41 to the first surface 42a of the counter electrode 42 is 4.8 [mm] in this embodiment.

The catalyst filter 34 is disposed downstream of the electrostatic filter 33. This catalyst filter 34 supports a catalyst on the surface of the substrate of a honeycomb structure, for example. As this catalyst, those which activate highly reactive substances in low-temperature plasma generated by discharge, such as manganese-based catalysts and noble metal-based catalysts, are used to promote decomposition of harmful and odorous components in the air.

Next, a circuit configuration example of the power supply means 45, which is a feature of the present invention, will be described with reference to FIG. The power supply means 45 is constituted by a high voltage power control section 61 and a high voltage power circuit section 62, and the high voltage power control section 61 and the high voltage power circuit section 62 are connected to each other. The high voltage power supply circuit section 62 is connected to the discharge electrode 41 and the counter electrode 42.

The high voltage power control unit 61 is provided with a high voltage power source 63 that is a primary power source and a controller 64 that controls the high voltage power circuit unit 62.

In the high voltage power supply circuit section 62, an oscillation circuit 65, a transistor 66, a transmission section 67, and a smoothing circuit 68 are arranged.

The oscillation circuit 65 is for applying a voltage (oscillation signal) to the transistor 66 to turn on / off this transistor 66. In addition, the transfer section 67 is for applying a voltage that periodically changes to the smoothing circuit 68 in response to the ON / OFF of the transistor 66. In this transmission part 67, the primary side 1st coil S11 and the primary side 2nd coil S12 are arrange | positioned at the primary side (oscillation circuit side), and the secondary side (smooth circuit side) ), The secondary first coil S21 is disposed. The primary first coil S11 repeats the energization / non-energization by the ON / OFF of the transistor 66 to generate a voltage boosted to increase the amplitude to the secondary first coil S21. . On the other hand, in the primary second coil S12, an induced voltage corresponding to the secondary voltage is generated, and the induced voltage is detected by the output voltage detection unit 69. Here, the output voltage detection unit 69 is configured to transmit an abnormal signal to the controller 64 when there is an error in the output voltage on the secondary side, for example.

The smoothing circuit 68 is composed of, for example, a cockcroft circuit in which a capacitor and a diode are combined. The smoothing circuit 68 smoothes the voltage boosted and amplified by the first coil S21 on the secondary side of the transmission section 67, and periodically fluctuates between both electrodes 41 and 42 of the discharge device 40. And to apply a voltage.

In the present embodiment, the output waveform of the voltage applied to the positive electrodes 41 and 42 is in the form of a sine curve as shown in FIG. 7. The voltage period Tv (voltage cycle) of the voltage becomes equal to or less than the period Ts (discharge cycle) of the streamer discharge generated in the form of a pulse. In other words, the voltage frequency fv is equal to or greater than the frequency fs (discharge frequency) of the streamer discharge generated in the form of a pulse.

The voltage frequency fv [kHz] has a relationship with the gap length G [mm] where (fv) [kHz] ≥k / G [mm] (where k is an experimentally determined coefficient and k = 40 [ mm / kHz]), and in this embodiment, the voltage frequency fv is 8.4 [kHz] or more. The amplitude Vp-p of this voltage is equal to or less than 10% of the average voltage Va output from the power supply means 45. In this embodiment, the average voltage Va is 4.0 [kV] and the amplitude of the voltage. (Vp-p) is 0.4 [KV] or less.

Operation operation

Next, the operation | movement operation of the air purification apparatus 10 is demonstrated.

As shown in FIG. 1 and FIG. 2, the centrifugal blower 26 is started during operation of the air purifier 10, and the indoor air flows through the air passage 25 in the casing 20. In this state, a voltage is applied to the ionizer 32 and the discharge device 40 from the power supply means 45 shown in FIG. At this time, a sine wave voltage shown in FIG. 7 is applied to the discharge device 40.

When indoor air is introduced into the casing 20, relatively large dust is first removed from the prefilter 31. When the indoor air passes through the ionizer 32 again, relatively small dust in the indoor air is charged and flows downstream, and the dust is collected by the electrostatic filter 33. As mentioned above, dust in air is substantially removed by the prefilter 31 and the electrostatic filter 33 from a large thing to a small thing.

In the discharge device 40 integrally incorporated in the ionization unit 32, as shown in FIG. 3, low-temperature plasma is generated toward the counter electrode 42 at the tip of the discharge electrode 41, whereby active reactive species having high reactivity ( Electrons, ions, ozone, radicals, etc.) are produced. When these active species reach the catalyst filter 34, they are further activated to decompose and remove harmful or odorous components in the air. As described above, the clean indoor air from which dust is removed and also harmful components and odor components are discharged from the air discharge port 24 into the room.

Effect of Embodiments

The following effects are exhibited in the air purification apparatus 10 which concerns on this embodiment.

In the present embodiment, the voltage frequency fv is equal to or greater than the discharge frequency fs. As a result, for example, the discharge delay time (dashed arrow period in FIG. 7) at the time of streamer discharge can be shortened as compared with the case where the voltage frequency fv is smaller than the discharge frequency fs (FIG. 6). .

This point will be described with reference to the graph shown in FIG. 8. 8 is a simulation result verifying how the delay time during streamer discharge changes according to the relationship between the voltage cycle Tv and the discharge cycle Ts. In FIG. 8, the horizontal axis represents a value obtained by dividing the discharge period Ts by the voltage period Tv. The vertical axis is a value obtained by dividing the discharge period Ts by the actual discharge period Ts'. Here, while the discharge period Ts is a minimum cycle required at the streamer discharge, the actual discharge cycle Ts' is obtained by simulating a cycle required by the actual streamer discharge. Therefore, in FIG. 8, when (Ts / Ts') on the vertical axis is close to 1.0, the discharge delay time is shortened, and conversely, when it is close to 0, it means that the discharge delay time is long.

In the simulation results, as shown in the oblique range of FIG. 8, when Ts / Tv < 1, that is, when the voltage period Tv becomes larger than the discharge period Ts, the discharge delay time tends to be remarkably long. It can be seen that. Therefore, the discharge loss in the discharge device 40 also increases. On the other hand, when (Ts / Tv) ≥ 1, that is, the voltage cycle Tv becomes less than the discharge cycle Ts, the discharge delay time becomes relatively short. In other words, when the voltage frequency fv becomes higher than the discharge frequency fs, the discharge delay time can be shortened, and the discharge loss of the discharge device 40 can be effectively reduced.

In the present embodiment, the power supply means 45 is configured to apply a voltage that satisfies the relationship of (fv) ≥ 40 / gap length (G). Here, this relation is demonstrated with reference to the graph of FIG.

As described above, the streamer discharge occurs in the form of a pulse due to the remaining of the charged particles 52. Therefore, the frequency fs of the streamer discharge is approximately governed by the residence time of the charged particles 52. 9 is a graph obtained by experimentally calculating the relationship between the gap length (G) and the discharge frequency (fs). As a result, within the range in which the streamer discharge is performed, the discharge frequency fs is approximately the relationship between the gap length G and the primary function, and the relationship is fs = 40 / G.

In this embodiment, since the discharge frequency fs is estimated based on this relational formula, and the voltage frequency fv is determined based on this discharge frequency fs, the voltage frequency fv is certainly higher than or equal to the discharge frequency fs. You can do Therefore, the discharge loss of this discharge device 40 can be reliably reduced.

In addition, in this embodiment, the power supply means 45 is made to apply the voltage of 10% or less amplitude Vp-p with respect to the average voltage Va to both electrodes 41 and 42. FIG. As a result, the range of voltages applied to both electrodes 41 and 42 is narrowed, and it is possible to suppress that the voltages applied to both electrodes 41 and 42 reach the spark region. Therefore, since spark generation can be suppressed, the stability of streamer discharge can be improved in this discharge device.

Other embodiment

This invention may be set as the following structures with respect to the said embodiment.

In the discharge device 40 of the above embodiment, the power supply means 45 is configured to output a voltage having a voltage frequency fv of 8.4 [kHz] or higher. However, the voltage frequency fv is preferably 20 [kHz] or more. In this case, the discharge delay time can be shortened to reduce the discharge loss, and the power frequency means 45 makes the frequency of sound corresponding to the voltage (amplitude signal) output from the power source means 45 higher than that of the human audible region. The nearby noise can be suppressed.

In the above embodiment, the power supply means 45 outputs the voltage of the sine wave output waveform. However, the output waveform of this power supply means may be any voltage as long as the voltage fluctuates periodically, such as square wave, sawtooth, and pulse.

As described above, the present invention is useful for a discharge device that is subjected to a periodically varying voltage to perform streamer discharge, and an air purifier having the discharge device.

Claims (5)

A plurality of discharge electrodes and a counter electrode opposing the discharge electrodes; In the discharge device for performing a streamer discharge between the two electrodes by applying a voltage periodically changing from the power supply means to the positive electrode, The frequency fv of the voltage applied to both electrodes and the frequency fs of the streamer discharge generated in the form of a pulse between the two electrodes, A discharge device characterized by satisfying a relational expression of fv≥fs. The method of claim 1, When the frequency (fv) [kHz] of the voltage applied to both electrodes and the distance (G) [mm] between both electrodes are set to k = 40 [mm / kHz], A discharge device characterized by satisfying a relationship of fv≥k / G. The method according to claim 1 or 2, The frequency fv [kHz] of the voltage applied to both electrodes is A discharge device characterized by satisfying a relation of fv≥20 [kHz]. The method according to claim 1, 2 or 3, The average voltage Va and amplitude Vp-p of the voltage applied to both electrodes are A discharge device characterized by satisfying a relational expression of Vp-p ≦ 0.1 × Va. And a discharge device for performing streamer discharge between the discharge electrode and the counter electrode, In the air purifying apparatus which distributes the to-be-processed air between both electrodes and cleans the to-be-processed air, The discharge device is an air purifier according to any one of claims 1 to 4.

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