JPH0446805Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a wet air purification device, and more specifically, for example, clean rooms for large factories handling food, medicine, precision machinery, semiconductors, etc.
This relates to the improvement of a wet air purifier used in offices, hospitals, etc., which removes dust from the air in the room by using a droplet flow area, controls humidity and temperature, and circulates it back into the room. be.

[Prior Art] Conventionally, this type of air purifying device connects an evaporator formed in a shower room to the indoor outlet via a blower, and connects a warmer to the indoor inlet. These evaporators and warmers are connected, and the entrances and exits of the heat exchange tubes provided in a meandering shape inside the evaporators and warmers are respectively connected to the refrigerator, and the heat exchange tubes are introduced into the evaporator from indoors. The air is cooled and humidified by being brought into contact with fine water droplets (cold water fine mist) produced by the water shower in the evaporator, and harmful components such as dust, bacteria, and viruses brought in from the room are removed. The heated air is further introduced into a heater, heated and controlled to an appropriate temperature and humidity, and then circulated indoors again, or a cyclone type is used as the evaporator and warmer. A method using a reverse Rankine cycle is known (see Japanese Patent Application Laid-Open No. 185922/1983).

[Problems to be solved by the invention] However, in such conventional air purifying devices, contact between dust in the air and fine mist of cold water,
Since cooling and heating are performed using separate equipment, it is necessary to prepare each equipment separately, and the piping and overall routes for them become long, and the blowing equipment for blowing air also becomes large or multiplied. There were problems in that the entire structure became larger and more complex, and the construction required more man-hours and costs increased.

Therefore, as a solution to such problems, the air to be cleaned, temperature controlled, and humidity controlled is positively or negatively charged using an ionization device to remove dust, dirt, and
An electric charge is applied to bacteria, etc., and then, in a gas-liquid contact tower, dust, etc. in the exhaust gas is captured in the ozone aqueous solution charged droplets by spraying charged droplets of an ozone aqueous solution with the opposite polarity to the electric charge of the dust etc. A device has been developed that collects the information (see Japanese Patent Publication No. 61-19274).

However, in conventional systems that bring charged dust into gas-liquid contact and collect the dust at the opposite pole to the charged part, the wind speed inside the gas-liquid contact tower cannot be increased, so the cross-sectional area of the tower body becomes large. The equipment becomes larger and the equipment becomes more complicated due to electrical insulation, which is disadvantageous both in terms of space and economy.Furthermore, there is a risk that dust that is not brought into contact with the gas and liquid may exist in the gas-liquid contact area. There is a problem in that the intended purpose of air purification cannot be achieved due to these dust particles.

[Means for solving the problem] This invention was made with the intention of solving the above problem, and in order to solve the above technical problem, relatively large dust and mist are It is an object of the present invention to provide a wet air cleaning device characterized in that after removing the dust, fine dust is removed by electrostatic precipitation.

That is, this invention has a cylindrical device main body, which has a cooling water tank in the lower part, an air inlet in the upper side part, and an air outlet in the upper part, and an air flow path is formed between them. , a cold water supply section disposed between an air inlet and an air outlet in the device main body, a gas-liquid contact section disposed below and upstream of this cold water supply section, and a gas-liquid contact section disposed below and upstream of this cold water supply section. In a wet air purifying device having an electrostatic precipitator and a reheating means disposed on the downstream side of the electrostatic precipitator,
A discharge section includes a discharge electrode having a plurality of pointed discharge needles projecting upward, and a discharge counter electrode that works together with the discharge electrode to control the electric charge of dust, etc. in the air, and is arranged downstream of the discharge section. It is an object of the present invention to provide a wet air cleaning device characterized by comprising a dust collecting section provided therein.

In this invention, the discharge counter electrode constituting the discharge section may be of any type as long as it can work together with the discharge electrode to charge dust, bacteria, etc. in the contaminated air; for example, it may be made of a net-like material. Alternatively, it is preferable to form a discharge counter electrode plate having a plurality of through holes located approximately at the center of the tip of the pointed discharge needle of the discharge electrode.

Further, the above-mentioned discharge part may be arranged in any manner as long as it is located downstream of the gas-liquid contact part and the discharge electrode of the discharge part has an upwardly pointed discharge needle. However, it is preferable that at least one side of the discharge section be inclined downward, and in this case, it is better that the lower end of the dust collection section be inclined approximately parallel to the discharge section. In addition, when at least one side of the discharge section is inclined, it is preferable to form a water drop guide section at the inclined lower end of the discharge electrode, or to form a water drain hole at the inclined lower end of the discharge return electrode. .

In addition, in this invention, the gas-liquid contact part disposed between the cold water supply part and the air inlet of the main body of the device prevents the cooling water sprayed from the cold water supply part from coming into contact with relatively large dust, etc. Any type of material may be used as long as it can collect these dusts and the like. Preferably, a water supply section and a fine water droplet removal section disposed above and downstream of the gas-liquid contact section are configured. At this time, the gas-liquid contact section receives cold water from the cold water supply section and contacts the dust, etc. in the contaminated air, so it is water resistant and can collect dust, bacteria, etc. in the air. For example, it must be possible to install multiple perforated plates or a perforated plate and a honeycomb core body arranged on the lower surface of the perforated plate, or a perforated plate and a honeycomb core body arranged parallel to the lower surface of the perforated plate. It is composed of a group of rectangular bent plates, preferably a plurality of collection bodies, and the honeycomb core body is formed of a plurality of laminated honeycomb core materials whose through holes are offset from each other. Good. In addition, the fine water droplet removal section disposed downstream of, or above, the cold water supply section in the device main body may have the same configuration as the cooling collection section or a mist eliminator with a honeycomb core body and bent plate structure. It may be a laminate of.

and downstream of the gas-liquid contact part in the device main body,
That is, the cold water supply section disposed above and dispersing cold water toward the cooling collection section may be of any type, and usually consists of a water sprinkler dispersing cold water circulated from within the cooling water tank. be done.

[Function] When the indoor contaminated air is sent into the main body of the device by driving the blowing means, first, cold water is sprayed from the cold water supply part at the gas-liquid contact part, comes into contact with the rising contaminated air, As a result, the falling cold water and the rising contaminated air come into countercurrent contact at the same time, and relatively large amounts of dust and bacteria in the contaminated air are efficiently transferred to the liquid side and collected. The fine dust that has passed through the gas-liquid contact area flows into the electrostatic precipitator, but
After being charged in the discharge section, the air is collected in the dust collection section and only the purified air is circulated indoors.
At this time, since the pointed discharge needle of the discharge electrode that constitutes the discharge part is provided to protrude upward, there is a risk that mist in the air that has passed through the gas-liquid contact part may adhere to the tip of the pointed discharge needle. There is no problem with the charging voltage.

[Example] An example of this invention will be described below based on the drawings.

◎ First Embodiment In FIG. 1, a schematic sectional view of a first embodiment of a wet air cleaning device according to an embodiment of this invention is shown. This wet air purifying device has a cylindrical shape that includes a cooling water tank 2 at the bottom, an air inlet 3 at the upper side, and an air outlet 4 at the top, forming an air flow path between them. A device main body 1, a cold water supply section 5 disposed downward between an air inlet 3 and an air outlet 4 in the device main body 1, and a cold water supply section 5 disposed downwardly and upstream of the chilled water supply section 5 to provide air flow for the air. A gas-liquid contact portion 6 horizontally arranged between the inlet 3 and the inlet 3;
A fine water droplet removing section 7 and an electrostatic precipitator 10 are disposed on the upper downstream side of the cold water supply section 5 and, if necessary, between the air outlet 4 and the air outlet 4.
and a reheating coil 9 as a reheating means, and an air flow path is formed on the upstream side of the air inlet 3 from the suction port 12 of the clean room 11 to the apparatus main body 1 via the blower fan 13, for example. There is also a clean room 1 on the downstream side of the air outlet 4.
An air flow path leading to the first outlet 14 is formed.

As shown in FIGS. 1 and 2, the electrostatic precipitator 10 includes a plurality of pointed discharge needles 15, 15...
This discharge electrode 16 has a discharge electrode 16 that projects upward.
It is composed of a discharge section 19 consisting of a discharge counter electrode 17 that works together with the discharge counter electrode 17 to manage the charge of dust, etc. in the air, and a dust collection section 20 disposed on the upper side, which is the downstream side of this discharge section 19. .

The discharge electrode 16 is formed of a plurality of strong conductive metal plates such as stainless steel, ordinary steel, copper, brass, aluminum, etc., with a plate thickness of 0.1 to 3.0 mm, preferably 0.2 to 1.0 mm, and Opposite 1
7 is formed of a discharge return electrode plate having a plurality of through holes 18, 18, . . . located approximately at the center of the tip of each pointed discharge needle 15. This discharge counter electrode 17
is formed of a metal plate such as an aluminum alloy or a resin substrate whose surface is coated with a conductive metal. In this case, the discharge counter electrode 17 has a plurality of through holes 1.
Although it is formed by a discharge return electrode plate having holes 18, 18..., it is not necessarily necessary to form it by a discharge return electrode plate having through holes 18, 18... The body 17a may constitute the discharge counter electrode 17. Further, as shown in FIG. 4, the discharge electrode 16 may be one in which a pointed discharge needle 15 is protruded from a plate material 16a by fixing means such as welding.

On the other hand, the dust collecting section 20, as shown in FIG. It is composed of dust collecting counter electrode plates 22, 22, . . . arranged so as to face the plates 21, 21, . In this case, the dust collecting section 20 is formed by at least a plurality of dust collecting electrode plates 2 parallel to the direction along the air flow.
It is also possible to configure only 1, 21, . . . .

As shown in FIG. 1, in this electrostatic precipitator 10, the discharge electrode 16 of the discharge section 19 is a cathode, the discharge counter electrode 17 is an anode, and
The power supply 23 is connected so that the dust collecting counter electrode plate 22 of the dust collecting electrode plate 21 becomes the cathode and the dust collecting electrode plate 21 serves as the anode, and thereby a predetermined voltage is applied between the discharge electrode 16 and the discharge counter electrode 17 of the discharge section 19. The applied voltage causes corona discharge between them, and the dust, bacteria, etc. charged by this corona discharge are transferred between the dust collection electrode plate 21 and the dust collection counter electrode plate 22 of the dust collection section 20 at a predetermined distance. The return electrode plate 22 collects charged dust, bacteria, etc. by applying a voltage.
The contaminated air from the clean room 11 can be purified by adsorption to the air.

The voltage used to perform such a corona discharge is a DC voltage obtained by transforming and rectifying a general AC power source (100V to 200V).
It can be carried out with a DC current of 4.5KV to -5KV and a discharge current of 2 to 20 μA per stitch, and the polarity relationship of the voltage applied between the discharge electrode 16 and the discharge counter electrode 17 at this time is as described above. Positive polarity discharge may be performed in the opposite relationship. Furthermore, the dust collecting electrode plate 2
Regarding No. 1, it is preferable to use a plate material having a gentle wave shape in the air flow direction in order to increase its area. In addition, when the discharge electrode 16 is connected to the cathode, the discharge counter electrode 17 and the dust collection electrode plate 21 may be connected to the ground side via the apparatus main body 1 to create a potential difference.

The gas-liquid contact section 6 also includes a set of a perforated plate having a large number of through holes (not shown) and disposed horizontally, and a collector having a honeycomb core arranged on the lower surface of the perforated plate. The cleaning device main body 1 is formed of a plurality of sets arranged at predetermined intervals from each other.
arranged horizontally within the The honeycomb core body may be formed of a single layer of honeycomb core material, but is preferably formed of a plurality of honeycomb core materials whose through holes are offset from each other.

Furthermore, the cold water supply section 5 disposed above the cooling collection section 6, that is, on the downstream side, is connected to the cooling water tank 2 via a circulation pump 24 and a flow meter 25, as shown in FIG. , water in the cooling water tank 2 is supplied in circulation. The cold water supply section 5 is configured by attaching a water sprinkler 28 opening downward to two branch pipes 27 branched from a pipe 26 connected to the cooling water tank 2, respectively. The cold water sprayed from this cold water supply section 5 is supplied to the cooling water tank 2.
It is possible to cool contaminated air below the dew point, and at a temperature that does not freeze. In this embodiment, a branch pipe 29 is provided in the circulation pipe 26 connecting the cooling water tank 2 and the cold water supply section 5, and the branch pipe 29 is connected to the lower upstream side of the cooling collection section 6. An auxiliary cold water supply section 5' similar to the above-mentioned cold water supply section 5 located at is connected, but it is not necessary to provide this auxiliary cold water supply section 5'. Further, a second branch line 29a is connected to the line 26, and a cleaning nozzle 40 disposed above the reheating coil 9 is connected to this branch line 29a via a switching valve 41. . This cleaning nozzle 40 is used after air cleaning, and is used for cleaning several minutes a day, for example, to clean the reheating coil 9 and the electrostatic precipitator 10. Note that the cleaning nozzle 40 may be connected to a water supply source (not shown) other than the cooling water tank 2, and in this case, it is connected to another water supply source via the pipe line 29b shown in phantom lines in FIG. .

The fine water droplet removing section 7 disposed above the cold water supply section 5, that is, on the downstream side, includes the gas-liquid contact section 6.
A honeycomb core body similar to the honeycomb core body constituting the honeycomb core body, a first mist eliminator disposed in contact with the upper surface of the honeycomb core body, and a first mist eliminator disposed at an appropriate interval above and downstream of the first mist eliminator. It is composed of a second mist eliminator and the like.

Then, it is disposed above the dust collection unit 8, that is, on the downstream side, and heats the purified air that has passed through the gas-liquid contact part 6, the fine water droplet dust collection part 7, and this electrostatic precipitator 10, As shown in FIG. 1, the reheating coil 9 that adjusts the temperature and humidity is composed of a meandering condenser, including a compressor 30 and an auxiliary condenser 3.
1. Together with the receiver tank 32, the cooling coil 34, and the accumulator 33, it constitutes a heat pump cycle. Note that the reheating coil 9 may be a hot water circulation heat exchanger connected to an electric heater or a separate heating source (not shown) without using a condenser.

Further, at the upper part of the cooling water tank 2, as shown in FIG. A cooling coil 34 is provided as a means, and this cooling coil 34 is also composed of a meandering evaporator like the reheating coil 9, and includes a compressor 30 shared with the reheating coil 9, and an auxiliary condenser 3.
1. Receiver tank 32 and accumulator 3
Together with 3, it constitutes a heat pump cycle.

As shown in FIG. 1, the cooling water tank 2 is equipped with a sterilizing means so that the cold water in the cooling water tank 2 can be sterilized and then supplied to the cold water supply section 5 or the auxiliary cold water supply section 5'. A sterilization tank 35 equipped with an ozone generator and an ultraviolet irradiator is connected, and the cold water in the cooling water tank 2 is sterilized in this sterilization tank 35 if necessary, and then supplied to the cold water supply section 5 or the auxiliary cold water supply section 5'. It is becoming more and more common. That is, the pipe line 26 supplies cold water from the cooling water tank 2 to the cold water supply section 5 or the auxiliary cold water supply section 5'.
The sterilization tank 3 is installed downstream of the circulation pump 24.
A bypass pipe line 36 is provided between the pipe line 26 and the bypass pipe line 36, and a switching valve 37 is provided between the pipe line 26 and the bypass pipe line 36 to switch the flow path of the cold water flowing therethrough. Therefore, cold water is supplied from the cooling water tank 2 directly or via the sterilization tank 35 to the cold water supply section 5, the cleaning nozzle 40, or the auxiliary cold water supply section 5'. In addition, when adding an ozone generator to the sterilization tank 35 for sterilization, water without dissolved ozone gas can be supplied via an ozone killer (ozone decomposition device), or when not via an ozone killer. In this step, water containing ozone (ozonated water) from an ozone generator (not shown) is introduced into the device body 1 to purify and sterilize the contaminated air, and at the same time sterilize each part inside the device body 1. It is also possible to prevent contamination of the device main body 1 by microorganisms and to facilitate maintenance.

In FIG. 1, the air flow path connecting the air inlet 3 of the apparatus main body 1 and the suction port 12 of the clean room 10 includes an outside air introduction pipe connected to the upstream side of the blower fan 13 via a switching valve 39. 38 is connected, and if necessary, outside air can be introduced from this outside air introduction pipe 38 through a coarse dust filter (not shown). In addition, reheating coils 9, which detect temperature and/or humidity, are installed near the air inlet 3, cold water supply section 5, and above and downstream of the fine water droplet removing section 7 near the air outlet 4 of the device main body 1, respectively. A sensor (not shown) sends a detection signal to a control device (not shown) that controls the heat pump cycle and the circulation pump 24, which are composed of the cooling coil 34, compressor 30, auxiliary condenser 31, receiver tank 32, accumulator 33, etc. ) are placed.

Therefore, according to the air purifying device of this embodiment, the contaminated air in the clean room 11 is sent into the device main body 1 by driving the blower fan 13, and inside the device main body 1, the cold water supply section 5 Cold water is sprayed from the air, contacts the gas-liquid contact section 6, forms a fluidized droplet bed to collect dust, etc. in the air, and then rises and contacts the fine water droplet removal section 7 to remove air. Most of the mist inside is removed. The air that has passed through the gas-liquid contact section 6 is sent to the electrostatic precipitator 10 disposed above the air, and is collected at the gas-liquid contact section 6 by the discharge section 19 of the electrostatic precipitator 10. After being charged, the fine dust and mist that have not been collected are collected by a dust collection part 20 having a polarity opposite to that of the discharge part 19. In this case, the pointed discharge needle 15 of the discharge electrode 16
Since the discharge needle 15 is provided to protrude upward, there is no possibility that mist remaining in the air that has passed through the gas-liquid contact portion 6 will adhere to the discharge needle 15 and cause trouble. That is, as shown in FIGS. 13 and 14, in the case where the discharge needle 15 of the discharge electrode 16 is provided to protrude downward, the mist 43 is placed at the tip of the discharge needle 15.
(Water droplets) adhere to the surface, causing overcurrent discharge and short circuits, causing a sudden change in the charging voltage and making it unstable.
It is possible to prevent the possibility of short circuits caused by falling onto the base side of the discharge needle 15 (see FIG. 2). In this case, as shown in FIG. 3, by forming the upper end of the discharge electrode 16 into a pointed shape, the water droplets 43
This makes it easier to handle the downward drop.

The air purified as described above is heated to a predetermined temperature (for example, about 25° C.) and humidity-controlled by the reheating coil 9, and then sent to the air outlet 14 of the clean room 11.

◎ Second Embodiment FIG. 5 is a cross-sectional view of the main part showing the second embodiment of this invention, and FIG. 6 is a perspective view of the main part. This is the case when it is made possible to do so. That is, one side of the discharge electrode 16 and the discharge counter electrode 17 of the discharge section 19 is tilted downward, and the lower ends of the dust collection electrode plate 21 and the dust collection counter electrode 22 of the dust collection section 20 are tilted downward.
In this case, the mist water droplets 43 adhering to the discharge electrode 16, the discharge counter electrode 17, the dust collection electrode plate 21, and the dust collection counter electrode 22 are moved to the lower side of the slope and easily disposed of. be. On this occasion,
By providing drain holes 42, 42, . ). In this case, the discharge section 1
The angle of inclination of the dust collecting section 9 and the dust collecting section 20 is preferably approximately 70 to 83 degrees with respect to the vertical wall 1' of the apparatus main body 1.
Further, the drain hole 42 may be a semicircular hole as shown in FIG. 6, or may be formed as a long hole 42a as shown in FIG. 7, or
It may also be formed with a slit 42b as shown in FIG. In this case, the drain holes 42, 42a,
Since there is a risk that uncharged air may pass through 2b, it is preferable to make it as small as possible within the range where water droplets 43 can flow down.

In the above explanation, one side of the discharge section 19 and the dust collection section 20 are respectively tilted downward to treat the water droplets 43 of the mist. However, this structure is not necessarily required, and as shown in FIG. As shown, the same effect can be obtained even if both sides of the discharge section 19 and the dust collection section 20 are respectively inclined downward.

In addition, in the second embodiment, by providing a water droplet falling guide section at the inclined lower end of the discharge electrode 16, smoother treatment of water droplets can be achieved. For example, as shown in FIGS. 10 and 11, the water droplet guide section includes water droplet guide troughs 44a and 44 having a loop-shaped cross section or a U-shaped cross section on the inclined lower edge of the discharge electrode 16.
b, or as shown in FIG. 12, it is preferable to provide a droplet guiding hanging piece 45 downward from the inclined lower end of the discharge electrode 16.

[Effects of the invention] As explained above, the wet air purifier of this invention has a gas-liquid contact part that removes relatively large dust particles from contaminated air using a fluidized bed of droplets of sprinkled cold water. The electrostatic precipitator installed on the upper downstream side is equipped with a discharge electrode having a plurality of pointed discharge needles projecting upward, and a discharge counter electrode that works together with the discharge electrode to control the electric charge of dust, etc. in the air. Since it is composed of a discharge section consisting of a discharge section and a dust collection section disposed downstream of this discharge section, the following effects can be obtained.

1. Relatively large dust, bacteria, etc. are removed by a physical method using gas-liquid contact, and then fine dust, etc. is removed by electrostatic precipitator, making it possible to efficiently remove dust, etc. from contaminated air. .

2. Since the pointed discharge needle that constitutes the discharge electrode of the discharge section is provided so as to protrude upward, mist in the air that has passed through the gas-liquid contact section will not adhere to the discharge section and interfere with the charging voltage. Therefore, stable charging can be performed, and dangers due to charge current discharge and short circuits can be avoided.

3. If water droplets attached to the discharge return electrode plate and water droplets attached to the lower end of the dust collection return electrode plate are easily moved to the downward side of the slope, short circuits due to water droplets between the dust collection return electrode plate and the discharge return electrode plate must be prevented. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a wet air purifier according to the first embodiment of this invention, FIG. 2 is an enlarged view of the discharge section in the first embodiment, and FIG. 3 is an enlarged sectional view of FIG. 2. Fig. 4 is an enlarged sectional view showing another form of the discharge section, Fig. 5 is a sectional view of the main part of the second embodiment of this invention, Fig. 6 is a perspective view of the main part, and Figs. 7 and 8. 9 is a perspective view of a main part of a discharge counter electrode in the second embodiment, FIG. 9 is a sectional view of a main part showing another form of the second embodiment, and FIGS. 10 to 12 are a discharge electrode in the second embodiment, respectively. FIG. 13 is a schematic sectional view of a conventional electrostatic precipitator, and FIG. 14 is an enlarged sectional view of FIG. 13. Explanation of symbols, 1...Device main body, 2...Cooling water tank, 3...Air inlet, 4...Air outlet, 5...
... Cold water supply section, 6 ... Gas-liquid contact section, 9 ... Reheating coil, 10 ... Electrostatic precipitator, 15 ... Pointed discharge needle, 16 ... Discharge electrode, 17 ... Discharge counter electrode, 17
a...Network, 18...Through hole, 19...Discharge part,
20...Dust collection part, 21...Dust collection electrode plate, 42...Drain hole, 42a...Long hole (water drain hole), 42b
...Slit (drain hole), 44a, 44b...
...Water droplet guide gutter (water droplet guide section), 45...
Water drop guide hanging piece (water drop guide part).

Claims (1)

[Claims for Utility Model Registration] (1) A cylinder having a cooling water tank at the bottom, an air inlet at the upper side, and an air outlet at the top, forming an air flow path between them. a shaped device main body, a cold water supply section disposed between an air inlet and an air outlet in the device main body, and a gas-liquid contact section disposed on the lower upstream side of the cold water supply section; In this wet air purifying device having an electrostatic precipitator and a reheating means disposed downstream of the gas-liquid contact part, the electrostatic precipitator is provided with a plurality of pointed discharge needles protruding upward. It consists of a discharge section consisting of a discharge electrode and a discharge counter electrode that works together with the discharge electrode to control the charge of dust collected in the air, and a dust collection section disposed downstream of the discharge section. A wet air purifying device characterized by: (2) The wet air purifying device according to claim 1, in which the discharge counter electrode is constituted by a net-like body. (3) Utility model registration claim 1, in which the discharge counter electrode is composed of a discharge counter electrode plate having a plurality of through holes in which the tip of the pointed discharge needle of the discharge electrode is located approximately in the center.
Wet air purifier as described in section. (4) The wet air purifier according to claim 1, wherein at least one side of the discharge section is inclined downward, and the lower end of the dust collection section is inclined substantially parallel to the discharge section. (5) The wet air purifying device according to claim 4, wherein a water droplet guide portion is formed at the inclined lower end of the discharge electrode constituting the discharge portion. (6) The wet air purifying device according to claim 4, wherein a water drain hole is formed at the inclined lower end of the discharge return electrode plate constituting the discharge section. (7) The wet air purifying device according to claim 1, wherein the dust collecting section has a plurality of dust collecting plates arranged along the air flow direction in the air flow path.