SE542942C2 - Discharge device and air-conditioning device equipped with same - Google Patents

Abstract

The present invention removes electric charges that have accumulated on an electrode, and resets the voltage required for discharging. A discharge device 9 is provided with a discharge electrode 12, a counter electrode 17, a high-voltage electrode 19, a ground electrode 20, a control unit 30, a high-voltage power supply 40 and the like. The counter electrode 17 is formed of a conductive resin having a volume resistivity of not more than 107 Ω·cm. When the output voltage of the high-voltage power supply 40 is less than a trigger voltage A, the control unit 30 executes a discharge mode, and causes the high-voltage power supply 40 to generate a discharge between the discharge electrode 12 and the counter electrode 17. When the output voltage of the high-voltage power supply 40 has reached the trigger voltage A, a transition is made to a voltage decrease mode, in which output of the voltage by the high-voltage power supply 40 is temporarily suspended. Further, when a lapse of time since the transition to the voltage decrease mode has reached a prescribed voltage decrease time, a transition is made to return to a discharge mode.

Description

DescriptionTitleDISCHARGE DEVICE AND AIR-CONDITIONING DEVICE EQUIPPED WITH SAME Field[0001]The present invention relates to a discharge device that executes a discharge for cleaning air, and an air-conditioning device equipped With the discharge device.

Background[0002] As conventional art, a discharge-type air-cleaning device for collecting particles ofdust or the like contained in air is known. The discharge-type air-cleaning device of theconventional art includes a charging unit for in1parting electric charges to the particles ofdust or the like and a dust collection unit for collecting particles iniparted With theelectric charges. Moreover, the charging unit includes a high-voltage electrode and aground electrode facing each other. The high-voltage electrode discharges When a highvoltage is applied, and the ground electrode is grounded. On the other hand, siniilarly,the dust collection unit also includes a high-voltage electrode and a ground electrode.Moreover, for example, in conventional art described in PTL l, the Weight of the entire device is reduced by forniing each electrode by use of a conductive resin.

Citation List Patent Literature[0003] [PTL 1] JP3729403B2[PTL 2] JP3730645B2 [PTL 3] JP4149526B2 Summary Technical Problem 4. 4. id="p-4" id="p-4"

[0004] In the aforementioned conventional art described in PTL l, the weight of the entire device is reduced by using the conductive resin as the electrodes. However, whenthe conductive resin is used, it is difficult to ensure conductivity as excellent as metal;therefore, charges are accumulated in the ground electrode due to electric resistance ofthe ground electrode, and a potential of the ground electrode is increased. As a result,when a surface potential of the ground electrode is increased, a voltage required fordischarging is also increased; accordingly, it is necessary to maintain a discharge currentby, for example, voltage control of the high-voltage power supply, and so forth.

However, there is, in general, an output upper limit to the high-voltage power supply, and,when the output reaches the output upper limit, output of the voltage is suspended, tothereby take time to retum. Further, in the high-voltage electrode of the dust collectionunit, in some cases, an actual voltage cannot follow the voltage control due to an effect ofa resistance value. In this case, a problem arises as to insufficient electric field strengthbetween the high-voltage electrode and the ground electrode to deteriorate dust collection performance. . . id="p-5" id="p-5"

[0005] The present invention has been made to solve the above problem, and has anobject to provide a discharge device and an air-conditioning device equipped with thesame which are capable of removing electric charges accumulated on an electrode, and resetting a voltage required for discharging.

Solution to Problem[0006] A discharge device according to the present invention includes: a dischargeelectrode for discharging; a counter electrode disposed so as to space away from thedischarge electrode, the counter electrode formed of a conductive resin having a volumeresistivity of no more than 107 Q-cm; a high-voltage power supply for applying an outputvoltage between the discharge electrode and the counter electrode; and a control meansfor controlling the output voltage of the high-voltage power supply to execute a dischargemode to discharge between the discharge electrode and the counter electrode by the high-voltage power supply to a maximum value of and a voltage not causing discharge between the discharge electrode and the counter electrode . f_- or lower than the maximum value . When the output voltage of the high-voltage power supplv is increased to a prescribed voltage, the control means transitions to the voltage decrease mode.

The control means is further configured to return to the discharge mode after the voltage decrease mode is continued for a prescribed time. The time to continue the voltage decrease mode is set in accordance with a resistance value of the conductive resin.

Advantageous Effects of Invention[0007] According to the present invention, it is possible to smoothly remove electriccharges accumulated on a counter electrode and a ground electrode by a voltage decrease mode. This makes it possible to reset the voltage required for discharging.

Brief Description of the Drawings 8. 8. id="p-8" id="p-8"

[0008] Fig. l is a cross-sectional view showing an indoor unit of an air-conditioning deviceaccording to Embodiment l of the present invention.

Fig. 2 is an exploded perspective view showing the discharge device according toEmbodiment l of the present invention.

Fig. 3 is a schematic view showing a configuration example of the discharge device.Fig. 4 is a block diagram of the control unit according to Embodiment l of the presentinvention.

Fig. 5 is a characteristics diagram showing an example of mode switching control in Embodiment l of the present invention.

Description of Embodiments. 9. 9. id="p-9" id="p-9"

[0009] Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described Withreference to Figs. 1 to 5. Note that, in each figure used in the description, commoncomponents are assigned the same reference sign, and redundant explanation will beomitted. Moreover, the present invention is not limited to the following embodiment,and is able to be modified in various forms within the scope not departing from the gist ofthe present invention. [00 1 0] Fig. 1 is a cross-sectional view showing an indoor unit of an air-conditioningdevice 1 according to Embodiment 1 of the present invention. Note that the air-conditioning device includes an indoor unit 1 disposed in a room to perform airconditioning and an outdoor unit (not shown) disposed outside of the room to performheat exchange or the like with the indoor unit 1. Moreover, Fig. 1 is a transverse cross-sectional view showing a state of the indoor unit 1 cut by a plane perpendicular to arotation axis of a ventilation fan 5. As shown in Fig. 1, the indoor unit 1 includes: an airinlet 2; an air outlet 3; heat exchangers 4; the ventilation fan 5; horizontal airflow plates6; vertical airflow plates 7; a front panel 8; a discharge device 9; and so forth. Of these,the heat exchangers 4, the ventilation fan 5 and the discharge device 9 are containedinside a housing 1A constituting an outer shell of the indoor unit 1. [001 1] The air inlet 2 is an opening part for sucking indoor air into the housing 1A, and isdisposed, for example, on an upper side of the housing 1A. The air outlet 3 is anopening part for blowing out air into the room from the housing 1A, and is disposed, for example, on a lower side of the housing 1A. The heat exchangers 4 cool or heat the air sucked from the air inlet 2. The Ventilation fan 5 sucks air from the air inlet 2, andbloWs air passed through the heat exchangers 4 toward the air outlet 3.[00 12] The horizontal airfloW plates 6 are disposed at the air outlet 3 and adjust adirection of air bloWn from the air outlet 3 (blowing angle) in a horizontal direction of theindoor unit l. The vertical airfloW plates 7 adjust a bloWing angle of air in a verticaldirection of the indoor unit l. Note that the horizontal direction of the indoor unit lrefers to a direction perpendicular to the page of Fig. l, and the vertical direction of theindoor unit l refers to the vertical direction in Fig. l. Moreover, the respective verticalairflow plates 7 are disposed at a front side and a back side as viewed from the front (thefront panel 8 side) of the indoor unit l. The front panel 8 constitutes a front surface partof the housing lA. [00 l 3] The discharge device 9 collects the particles, such as dust, contained in air by anelectrostatic force, to thereby clean the air. The discharge device 9 is disposed on anupstream side (WindWard side) of the heat exchangers 4 in the air floW from the air inlet 2toward the air outlet 3. Note that the discharge device of the present invention is notnecessarily limited to a device co llecting the particles, such as dust, and includes variouskinds of discharge-type air-cleaning devices that perform discharge in air for cleaning theair. To describe specifically, the discharge device may be a device for decomposing andinactivating contaminants, for example, made of particles, smoke, pollen, viruses, molds,bacteria, allergens, odor materials, ions, radicals, and so forth floating in air bydischarging. Moreover, the discharge device of the present invention may be disposed on a downstream side (leeWard side) of the heat exchangers 4. [00 14] Next, with reference to Figs. 2 and 3, a configuration of the discharge device 9will be described. Fig. 2 is an exploded perspective view showing the discharge deviceaccording to Embodiment 1 of the present invention. Note that, in Fig. 2, the X-axisdirection corresponds to the horizontal direction of the indoor unit 1, and the Y-axisdirection corresponds to a front-back direction of the indoor unit 1 (the horizontaldirection in Fig. 1). Moreover, an upper side of the Z-axis direction corresponds to thewindward direction of the air flowing inside the indoor unit 1. On the other hand, Fig. 3is a schematic view showing a configuration example of the discharge device. Thefigure intends to schematically show arrangement and connection of each electrode of thedischarge device 9. Consequently, in Fig. 3, illustration of components is partiallyomitted, and shapes of components differ from those in Fig. 2 in some cases. [00 1 5] As shown in Figs. 2 and 3, the discharge device 9 includes: an upper frame 10; alower frame 11; a discharge electrode 12; a spring 13; a power feeding unit 14; electrodesupport units 15 and 16; a counter electrode 17; a dust collection unit 18; a control unit30; a high-voltage power supply 40; and so forth. The upper frame 10 constitutes, asshown in Fig. 2, a portion, of the discharge device 9, disposed at the most windward side.Moreover, the lower frame 11 constitutes a portion, of the discharge device 9, disposed atthe most leeward side. These frames 10 and 11 are, for example, formed of a resinmaterial as a whole, and extend in parallel with the X-axis direction while spacing awayfrom each other in the Z-axis direction. 16. 16. id="p-16" id="p-16"

[0016] Moreover, in the upper frame 10, multiple openings for taking outside air into thedischarge device 9 are forrned. Each of the openings is separated into a grid pattem tohave a configuration such that a person's finger or the like cannot enter the inside of thedischarge device 9 from the openings. Each of the openings is arranged on a top surfacepart of the upper frame 10, for example, in groups of multiple openings arranged in linesin the X-axis direction (the width direction) and the Y-axis direction (the front-backdirection). In the lower frame 11, similar to the upper frame 10, multiple openings areformed in a state of being arranged in a grid pattem. [00 1 7] Between the discharge electrode 12 and the counter electrode 17, an outputvoltage of the high-voltage power supply 40 capable of outputting a high voltage, forexample, of the order of 4 kV to 7 kV is applied. The discharge electrode 12 is formedby, for example, fo lding an interrnediate part of a long metal plate once to four times, andextends in the X-axis direction. Note that, in Fig. 2, the discharge electrode 12 in a Ushape formed by folding the metal plate once is exemplified. To each of both endportions of the discharge electrode 12, a terminal in a ring shape is attached. As amaterial of the discharge electrode 12, it is preferable to use, for example, a metallicmaterial, such as tungsten, copper, nickel, stainless steel, zinc, iron or molybdenum, analloy containing these metallic materials as a main component, or the like. Moreover,the discharge electrode 12 may be formed by plating a surface of the above-describedmetallic material with a precious metal, such as silver, gold or platinum, or by forming acarbon (graphite) layer, an oxide film, or the like on the surface. 18. 18. id="p-18" id="p-18"

[0018] The cross-sectional shape of the discharge electrode 12 is formed into, forexample, a flat rectangular shape including long sides and short sides. In the cross-sectional shape, the long side is made to have a length, for example, of the order of 0.1mm to 1.0 mm, and the short side is made to have a length, for example, of the order of0.01 mm to 0.1 mm. By forming the cross-sectional shape of the discharge electrode 12into the rectangular shape, as compared to, for example, an electrode having a circularcross-sectional shape, the electric field strength around the electrode can be increased.This makes it possible to stably inactivate mo lds, bacteria, allergens, viruses or otherspassing near the discharge electrode 12. Moreover, a charge amount of the dust or thelike passing near the discharge electrode 12 can be efficiently increased. [00 1 9] The spring 13 is a member for imparting a tension to the discharge electrode 12,and is formed of a metallic material. The spring 13 is coupled to the terrninals on bothsides of the discharge electrode 12. The discharge electrode 12 is attached to the powerfeeding unit 14 in a state of being pulled by the spring 13 in the longitudinal direction,and is electrically connected to the power feeding unit 14. The power feeding unit 14 isa member for applying a voltage outputted from the high-voltage power supply 40 to thedischarge electrode 12 and the high-voltage electrode 19, and is formed of a conductivematerial, such as a metal. Note that, in the present invention, it may be possible to havea configuration in which each of the discharge electrode 12 and the high-voltageelectrode 19 is connected to each of different power feeding members, and the voltagesapplied to the discharge electrode 12 and the high-voltage electrode 19 can beindividually controlled. . . id="p-20" id="p-20"

[0020] _10- The electrode support units 15 and 16 support the discharge electrode 12 inside the discharge device 9, and the entirety thereof is formed of, for example, a resin material.

The electrode support unit 15 is attached to one end side of the lower frame 11 in thelength direction (the X-axis direction). Moreover, the electrode support unit 16 isattached to, for example, the other end side of the upper frame 10 in the length direction.In this state, the electrode support units 15 and 16 are configured to support the both endsides of the discharge electrode 12. The electrode support units 15 and 16 include amember for supporting the discharge electrode 12 in the folded state, a member forretaining the discharge electrode 12 at a suitable position, and so forth.[002 1 ] The counter electrode 17 is an electrode to be paired with the discharge electrode12, and is formed of, for example, a conductive resin into an elongated flat plate shape.To cite an example, the counter electrode 17 includes, as shown in Fig. 2, for example,three electrode plates. These electrode plates extend in the X-axis direction, anddisposed at intervals mutually in the Y-axis direction. Then, the discharge electrode 12is disposed among the respective electrode plates of the counter electrode 17 with gaps.Consequently, the discharge electrode 12 and the counter electrode 17 are configured tospace away from each other in the Y-axis direction.[0022] Moreover, the counter electrode 17 is integrally molded with the ground electrode20 to be described later by use of, for example, a conductive resin having a volumeresistivity of not more than 107 Q-cm. Note that the conductive resin is generallydefined as a resin having a volume resistivity of not more than 107 Q-cm. Such a conductive resin is formed by, for example, blending a conductive material, such as _11- carbon black, carbon fiber, conductive whisker or metallic fiber in a base resin.Moreover, the counter electrode 17 and the ground electrode 20 are grounded via agrounding power feeding unit 21. 23. 23. id="p-23" id="p-23"

[0023] The dust collection unit 18 collects the dust or the like charged (imparted withelectric charges) by passing between the discharge electrode 12 and the counter electrode17, and includes the high-Voltage electrode 19 and the ground electrode 20. Betweenthe high-Voltage electrode 19 and the ground electrode 20, an output Voltage from thehigh-Voltage power supply 40 is applied. The high-Voltage electrode 19 includes, forexample, multiple electrode pieces arranged at regular interVals in the X-axis direction.Each electrode piece constituting the high-Voltage electrode 19, for example, projectstoward the counter electrode 17 in the Z-axis direction and extends in parallel with the Y-axis direction. Moreover, the high-voltage electrode 19 is formed of, for example, asemi-conductive resin having a Volume resistance lower than those of the counterelectrode 17 and the ground electrode 20. To cite an example, the semi-conductive resinhas a Volume resistance of the order of 108 Q-cm to 1013 Q-cm. Moreover, the high-Voltage electrode 19 is electrically connected to the power feeding unit 14. 24. 24. id="p-24" id="p-24"

[0024] The ground electrode 20 is an electrode to be paired with the high-Voltageelectrode 19, and is integrally molded with the counter electrode 17 by use of theaforementioned conductive resin. The ground electrode 20 includes, for example,multiple electrode pieces arranged at regular interVals in the X-axis direction. Eachelectrode piece constituting the ground electrode 20, for example, projects toward the high-Voltage electrode 19 in the Z-axis direction and extends in parallel with the Y-axis _12- direction. When the discharge device 9 is assembled, the high-voltage electrode 19 andthe ground electrode 20 are, as shown in Fig. 3, retained in a state of spacing away fromeach other in the X-axis direction, where the electrode pieces thereof are altematelyarranged into engagement with each other. . . id="p-25" id="p-25"

[0025] In this manner, by forming the counter electrode 17, high-voltage electrode 19 andthe ground electrode 20 by the resin material, it is possible to promote weight reductionof the entire discharge device 9, and to simplify the processing of each of the electrodes17, 19 and 20. Moreover, in a case of a metallic electrode, the electrode shape has a lowdegree of flexibility because press work and bending work are required, whereas,according to the embodiment, the degree of flexibility of each of the electrodes 17, 19and 20 can be improved. In addition, since the counter electrode 17 and the groundelectrode 20 are integrally molded, it is possible to simplify a structure of the entireelectrode, and to further promote downsizing and weight reduction of the dischargedevice 9. Moreover, since the resin electrode has high charge retention ability ascompared to the metallic electrode, intervals between the electrodes can be reduced.This makes it possible to increase the electric field strength between the electrodes, tothereby improve the dust collection ability. 26. 26. id="p-26" id="p-26"

[0026] Next, the control unit 30 as control means for controlling operations of the high-voltage power supply 40 will be described. The control unit 30 is composed of amicrocomputer and the like, and, as shown in Fig. 3, includes a processor 30A and amemory 30B. The fianction of the control unit 30 is achieved by the processor 30A executing programs stored in the memory 30B. Note that the control unit 30 may also _13- serve as a control device for controlling operations of the air-conditioning device, or maybe a control device dedicated to control operations of the high-voltage power supply 40only. Moreover, the control unit 30 may be composed of components separated fromthe high-voltage power supply 40, or may be an integrated control circuit incorporated inthe high-voltage power supply 40. 27. 27. id="p-27" id="p-27"

[0027] Fig. 4 is a block diagram of the control unit according to Embodiment l of thepresent invention. As shown in the figure, the control unit 30 is communicablyconnected to the high-voltage power supply 40, and includes a voltage control unit 3 l, avoltage deterrnination unit 32, a mode switching unit 33 and so forth. The voltagecontrol unit 3l controls the output voltage of the high-voltage power supply 40 so that adischarge current generated between the discharge electrode 12 and the counter electrodel7 has a constant current value. 28. 28. id="p-28" id="p-28"

[0028] The voltage deterrnination unit 32 compares the output voltage of the high-voltagepower supply 40 (that is, a voltage applied to the discharge electrode l2 and the high-voltage electrode 19) with a preset trigger voltage A, to be described later, and outputsthe comparison result to the mode switching unit 33. The mode switching unit 33switches the operation mode of the discharge device 9 between a discharge mode and avoltage decrease mode, to be described later, based on the deterrnination result of thevoltage deterrnination unit 32, or the like. 29. 29. id="p-29" id="p-29"

[0029] (Operation of Embodiment l) _14- Next, operations of the air-conditioning device will be described with reference toFig. l. First, when the air-conditioning device is actuated, the heat exchangers 4, theventilation fan 5 and the discharge device 9 are driven. When the ventilation fan 5 isactuated, the indoor air is sucked from the air inlet 2, and an air flow is generated insidethe indoor unit l. As a result, after being cleaned by passing through the dischargedevice 9, the sucked air is cooled or heated by passing through the heat exchangers 4.The air passed through the heat exchangers 4 successively passes positions of theventilation fan 5, the horizontal airflow plates 6 and the vertical airflow plates 7, and issent into the rooni fron1 the air outlet 3. Consequently, air conditioning in the rooni canbe perforrned. . . id="p-30" id="p-30"

[0030](Discharge mode) Next, with reference to Fig. 3, operations of the discharge device 9 will bedescribed. First, in an initial state, it is assun1ed that the discharge device 9 is in adischarge n1ode. In the discharge n1ode, the output voltage of the high-voltage powersupply 40 is applied to the discharge electrode 12 and the high-voltage electrode l9.Consequently, between the discharge electrode 12 and the counter electrode l7, adischarge current is generated in accordance with the output voltage, and thereby anelectric field having a prescribed strength is generated. [003 l] At this tin1e, the voltage control unit 3l n1aintains the discharge current betweenthe electrodes l2 and l7 at a constant current value by controlling the output voltage ofthe high-voltage power supply 40. In this state, the air to pass through the discharge device 9 first passes between the discharge electrode l2 and the counter electrode l7. _15- As a result, particulate materials, such as dust, bacteria, molds, viruses, pollen orallergenic materials, floating in the air are brought into a charged state by discharging andthe electric field between the electrodes 12 and 17. 32. 32. id="p-32" id="p-32"

[0032] Next, the particulate materials having been charged pass between the high-voltageelectrode 19 and the ground electrode 20 in the dust collection unit 18 together with theair. Since the output voltage of the high-voltage power supply 40 is applied to the high-voltage electrode 19, similar to the discharge electrode 12, an electric field having aprescribed strength is generated between the high-voltage electrode 19 and the groundelectrode 20. As a result, when passing between the high-voltage electrode 19 and theground electrode 20, the particulate materials in the charged state adhere to the groundelectrode 20 upon receiving large Coulomb force. Consequently, the particulatematerials are collected by the dust collection unit 18 and removed from the air. 33. 33. id="p-33" id="p-33"

[0033] Here, when discharge is continued between the discharge electrode 12 and thecounter electrode 17, the electric charges are accumulated on the counter electrode 17having a resistance value, and a surface potential is generated. As a result, between thedischarge electrode 12 and the counter electrode 17, the electric field and the dischargecurrent are on a declining trend. To deal with the phenomenon, by increasing the outputvoltage of the high-voltage power supply 40 by the voltage control unit 31, it is possibleto maintain the prescribed discharge current. However, there is, in general, an upperlimit of the output voltage to the high-voltage power supply 40, and, when the outputvoltage reaches the upper limit value, output of voltage is forcibly suspended by a safety device and a recovery mode is tumed on in some cases. In this case, there is a problem _16- that performance of the discharge device 9 is unavailable during the recovery mode. Onthe other hand, if discharge is continued, a problem occurs also in the dust collection unit18 as follows. In the dust collection unit 18, since the high-voltage electrode l9 has ahigh volume resistance, even though the output voltage of the high-voltage power supply40 is increased, a following capability of the voltage with respect to the output voltage isnot good. As a result, between the high-voltage electrode 19 and the ground electrode20, since the Voltage between the electrodes 19 and 20 cannot sufficiently follow theoutput voltage of the high-voltage power supply 40, there is a possibility that the electricfield strength is reduced, and the dust collection performance is deteriorated. 34. 34. id="p-34" id="p-34"

[0034] To solve these problems, as shown in Fig. 5, the control unit 30 executes modeswitching control to altemately repeat the discharge mode and the voltage decrease mode.Fig. 5 is a characteristics diagram showing an example of mode switching control inEmbodiment l of the present invention. The bold line in the figure indicates the outputvoltage of the high-voltage power supply 40 controlled by the voltage control unit 3 l,and the dotted line indicates dust collection efficiency of the particulate materials by thedust collection unit 18. Note that the dust collection efficiency can be calculated basedon, for example, a difference between the number of particulate materials measured onthe upstream side and the downstream side of the discharge device 9. . . id="p-35" id="p-35"

[0035] In the mode switching control, first, when the output voltage of the high-voltagepower supply 40 is less than a prescribed voltage (trigger voltage A), the above-describeddischarge mode is executed. In the discharge mode, the electric charges are accumulated on the counter electrode l7 by discharging, and the electric field and the _17- discharge current between the discharge electrode 12 and the counter electrode 17 arereduced. Therefore, for example, as shown in the left side of Fig. 5, as the duration timeof the discharge mode is longer, the voltage control unit 31 increases the output voltageof the high-voltage power supply 40 for supplementing the discharge current. 36. 36. id="p-36" id="p-36"

[0036] (Voltage decrease mode) The voltage deterrnination unit 32 deterrnines whether or not the output voltage of the high-voltage power supply 40 has reached the trigger voltage A in the discharge mode.

Then, when the deterrnination is made, the deterrnination result is outputted to the modeswitching unit 33. Consequently, the mode switching unit 33 outputs a signalcorresponding to the Voltage decrease mode to the voltage control unit 31 to switch theoperation mode of the discharge device 9 from the discharge mode to the voltagedecrease mode. [003 7] As a result, for example, as shown in the center of Fig. 5, the voltage control unit 31 suspends output of the voltage by the high-voltage power supply 40, and thereby thedischarge device 9 moves into the voltage decrease mode. Note that the high-voltagepower supply 40 has a preset output upper limit value, and is configured to suspendoutput of the voltage when the output voltage has reached the output upper limit value.The trigger voltage A is set at a voltage value lower than the output upper limit value anda voltage value by which the electric charges are likely to be accumulated on the counterelectrode 17. Consequently, in a situation that accumulates the electric charges on the counter electrode 17, it is possible to surely execute the voltage decrease mode. 38. 38. id="p-38" id="p-38"

[0038] _18- In the Voltage decrease mode, the output Voltage of the high-Voltage power supply40 is temporarily decreased, to maintain the output Voltage at a Voltage Value lower thanthe minimum discharge Voltage B shown in Fig. 5. The minimum discharge Voltage Bis a minimum Voltage Value causing discharge between the discharge electrode 12 and thecounter electrode 17. In other words, the output Voltage achieved by the Voltagedecrease mode is set equal to a maximum value of the Voltage not causing dischargebetween the electrodes 12 and 17, or lower than the maximum Value. Consequently,during the Voltage decrease mode, discharge between the electrodes 12 and 17 falls intothe suspended state. In this manner, since discharge can be suspended in the Voltagedecrease mode, it is possible to preVent new electric charges from being supplied to thecounter electrode 17 and the ground electrode 20 by discharge. This makes it possibleto eliminate the potential generated on the electrodes 17 and 20, and to remoVe theaccumulated electric charges. In other words, it is possible to initialize the electric fieldstrength between the ground electrode 20 integrally molded with the counter electrode 17and the high-Voltage electrode 19, and thereby restore the dust collection performance ofthe dust collection unit 18. 39. 39. id="p-39" id="p-39"

[0039] MoreoVer, for example, when an elapsed time from transition to the Voltagedecrease mode reaches the prescribed Voltage decrease time, the mode switching unit 33outputs a signal corresponding to the discharge mode to the Voltage control unit 31, toswitch the operation mode of the discharge deVice 9 from the Voltage decrease mode tothe discharge mode. As a result, the Voltage control unit 31 perrnits output of theVoltage by the high-Voltage power supply 40, and thereby the discharge deVice 9 retums to the discharge mode. Note that it is preferable to preset the Voltage decrease time, _19- Which is the time of continuing the Voltage decrease mode, in accordance With, forexample, a resistance value of the conductive resin forrning the counter electrode 17 andthe ground electrode 20 or a charge relaxation time. 40. 40. id="p-40" id="p-40"

[0040] Consequently, the voltage decrease time can be appropriately set in accordanceWith the minimum time required to remove the potential and electric charges from thecounter electrode l7 and the ground electrode 20. Accordingly, the duration time of thevoltage decrease mode, that is, the suspension time of the discharge device 9 can be asshort as possible, and the dust collection performance can be restored early While stablyremoving the potential of the counter electrode l7. [004 l ] Note that, in the embodiment, the case in Which output of the high-voltage poWersupply 40 Was suspended during the voltage decrease mode Was exemplified. However,the present invention is not limited thereto, and may have a configuration in Which, forexample, in the voltage decrease mode, an output potential (polarity) of the high-voltagepower supply 40 is reversed against the discharge mode. With this configuration, also,effects similar to those in Embodiment l can be obtained. 42. 42. id="p-42" id="p-42"

[0042] As described in detail above, according to the embodiment, it is possible tosmoothly remove the electric charges accumulated on the counter electrode l7 and theground electrode 20 by the voltage decrease mode. This makes it possible to reset thevoltage required for discharging. Consequently, as described above, it is possible toavoid forcible suspension of output of the voltage due to the output voltage of the high- voltage poWer supply 40 reaching the upper limit value, and to stably activate the _20- discharge device 9. In other Words, in the embodiment, the voltage can be decreased bythe voltage decrease mode before transition to the recovery mode is made by forciblesuspension of the high-voltage power supply 40. As a result, the time during Whichdischarge is suspended by the recovery mode (namely, the suspension time ofperformance of the discharge device 9) can be reduced. Moreover, by resetting thevoltage required for discharging, the dust collection performance of the dust collectionunit 18 can be restored. This makes it possible to improve the dust collectionperformance of the discharge device 9 and the air-conditioning device. Then, thedischarge device 9 configured like this and the air-conditioning device equipped With thesame can be installed in appliances, such as various types of air-conditioning devices, aircleaners or bloWers located in, for example, living rooms at home, off1ces, stores and soforth, or can be installed by providing a fan to elevators, ducts and the like. 43. 43. id="p-43" id="p-43"

[0043] Note that, in the embodiment, explanation Was given by taking the dischargedevice 9 including the dust collection unit 18 as an example. HoWever, the presentinvention is not limited thereto, and is applicable to a discharge device Without includingthe dust collection unit 18. Even in this case, since it is possible to avoid forciblesuspension of output of the voltage due to the output voltage of the high-voltage power supply reaching the upper limit value, the above-described effects can be obtained.

Reference Signs List[0044]l Indoor unit, lA Housing, 2 Air inlet, 3 Air outlet, 4 Heat exchanger, 5 Ventilation fan, 6 Horizontal airfloW plates, 7 Vertical airfloW plates, 8 Front panel, 9 Discharge _21- device, 10 Upper frame, 11 Lower frame, 12 Discharge electrode, 13 Spring, 14 Powerfeeding unit, 15, 16 Electrode support units, 17 Counter electrode, 18 Dust collection unit,19 High-voltage electrode, 20 Ground electrode, 21 Grounding power feeding unit, 30Control unit (Control means), 30A Processor, 30B Memory, 31 Voltage control unit, 32 Voltage deterrnination unit, 33 Mode switching unit, 40 High-Voltage power supply.

Claims (5)

_22-

1. [Claim 1]

2. A discharge device (9) comprising: a discharge electrode (12) for discharging; a counter electrode (17) disposed so as to space away from the discharge electrode(12), the counter electrode (17) formed of a conductive resin having a volume resistivityof no more than 107 Q-cm; a high-voltage power supply (40) for applying an output voltage between thedischarge electrode (12) and the counter electrode (17); and a control means (30) for controlling the output voltage of the high-voltage powersupply (40) to eXecute a discharge mode to discharge between the discharge electrode(12) and the counter electrode (17) by the high-voltage power supply (40) and a voltagedecrease mode to decrease temporarily the output voltage of the high-voltage powersupply (40) to a maximum value of a voltage not causing discharge between the dischar- ge electrode ( 12) and the counter electrode ( 17), or lower than the maximum value,-t-he- eleetrode-HJ), wherein, when the output voltage of the high-voltage power supply (40) is increased to a prescribed voltagefthiecontrol means (30) transitions to the voltage decrease mode, and the control means (30) is configured to retum to the discharge mode after the vol-tage decrease mode is continued for a prescribed time, and the time to continue the volta-ge decrease mode is set in accordance with a resistance value of the conductive resin.[Claim 2]

3. The discharge device (9) according to claim 1, comprising: _23- a dust collection unit (18) for collecting dust charged by passing between thedischarge electrode (12) and the counter electrode (17), wherein the dust collection unit (18) comprises: a high-voltage electrode (l9); and a ground electrode (20) integrally molded with the counter electrode (17) andmade of the conductive resin, and disposed so as to space away from the high-voltageelectrode (19), and the discharge device (9) is configured to apply an output voltage of the high- voltage power supply (40) between the high-voltage electrode (19) and the ground electrode (20).

4. [Claim 4 å] The discharge device (9) according to any one of claims 1 to 3 2, wherein a cross-sectional shape of the discharge electrode (12) is formed into a flat shape with a long sideand a short side having lengths different from each other.

5. [Claim 5 å]An air-conditioning device comprising the discharge device (9) according to any one of claims 1 to 4 å.