WO2022176711A1

WO2022176711A1 - Air purifier

Info

Publication number: WO2022176711A1
Application number: PCT/JP2022/004924
Authority: WO
Inventors: 啓輔山城; 規浅田; 伸松本; 延章大栗; 章朝瑞慶覧; 裕俊杉山; 翔寺沢
Original assignee: 富士電機株式会社; 学校法人幾徳学園
Priority date: 2021-02-17
Filing date: 2022-02-08
Publication date: 2022-08-25
Also published as: JP7041930B1; JP2022125531A

Abstract

Provided is an air purifier comprising: an interior space that is interposed between a suction port and a blow port; a charging device that charges microparticles contained in air that flows into the interior space from the suction port; a humidifying device that humidifies the air; a collection device that uses electrostatic force to collect the charged microparticles from the air; and an ejection device that ejects air from the collection device to the blow port. The charging device charges the microparticles by using corona discharge, for example.

Description

Air cleaner

The present disclosure relates to air purifiers.

Conventionally, an electric dust collection type air cleaner that charges dust particles contained in the air and collects the charged dust particles by electrostatic adsorption is known (see Patent Document 1, for example).

JP-A-2001-79077

　The need for countermeasures against new coronavirus infections and influenza is rapidly increasing in environments where there are many sick people and people, such as hospitals, movie theaters, various transportation facilities, and ships. Therefore, there is a need for a means of inactivating airborne viruses or pathogenic bacteria.

However, although the electrostatic precipitator function alone can collect fine particles (viruses or bacteria. Microscopic substances such as dust containing viruses or bacteria can also be collected), the collected viruses or bacteria cannot be inactivated.

The present disclosure provides an air purifier capable of inactivating captured viruses or bacteria.

This disclosure is
an internal space interposed between the inlet and the outlet;
a charging device that charges fine particles contained in the air flowing from the suction port into the internal space;
a humidifying device for humidifying the air;
a collection device that collects charged fine particles from the air by electrostatic force;
and a discharging device for discharging the air from the collecting device to the outlet.

According to the technology of the present disclosure, it is possible to provide an air cleaner capable of inactivating the collected viruses or bacteria.

It is a figure which shows an example of the air cleaner of one Embodiment. 1 is a schematic diagram showing a first configuration example of a charging device in an air cleaner of one embodiment; FIG. FIG. 4 is a schematic diagram showing a second configuration example of the charging device in the air cleaner of one embodiment; It is a schematic diagram which shows the structural example of the collection apparatus in the air cleaner of one Embodiment. It is a schematic diagram which shows the 1st structural example of the air cleaner of one Embodiment. It is a schematic diagram which shows the 2nd structural example of the air cleaner of one Embodiment. FIG. 10 is a diagram showing an example of verification results of the survival rate of Staphylococcus aureus before humidification at each position in the internal space. FIG. 10 is a diagram showing an example of verification results of the survival rate of Staphylococcus aureus after humidification at each position in the internal space. FIG. 10 is a diagram showing an example of the results of verification of virus viability before humidification at each position in the internal space. FIG. 10 is a diagram showing an example of the verification result of virus viability after humidification at each position in the internal space. FIG. 5 is a diagram showing an example of the relationship between the applied voltage and the discharge current depending on the difference in the polarity of the discharge electrodes in the charging device; FIG. 5 is a diagram showing an example of the relationship between discharge current and ozone concentration depending on the difference in polarity of discharge electrodes in a charging device;

Hereinafter, embodiments for implementing the technology of the present disclosure will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of an air purifier according to one embodiment. An air purifier 100 shown in FIG. 1 is a device for purifying air. The air purifier 100 includes a housing 10 that houses devices for purifying air. The housing 10 has an intake port 11 for sucking air from the outside of the air cleaner 100 and an outlet port 12 for blowing out the air cleaned by devices inside the housing 10 to the outside of the air cleaner 100 .

In the example shown in FIG. 1, the suction port 11 is provided at one end (eg, lower portion) of the housing 10, and the outlet 12 is provided at the other end (eg, upper portion) of the housing 10. . The respective positions of the suction port 11 and the blowing port 12 are not limited to this, and may be other locations. The installation number of each of the suction port 11 and the blowing port 12 may be one or more.

The air cleaner 100 includes an internal space 20, a charging device 30, a humidifying device 40, a collecting device 50, a discharging device 60 and a control device 80. The positional relationship of each device shown in FIG. 1 is merely an example, and is not limited to this as long as the desired effect of inactivating viruses or bacteria is achieved.

The internal space 20 is a space that exists inside the housing 10 and is interposed between the inlet 11 and the outlet 12 . In the example shown in FIG. 1, the internal space 20 is a flow path that connects the suction port 11 to the blowout port 12, and the air flowing in from the suction port 11 flows.

The charging device 30 is a device that charges fine particles contained in the air flowing from the suction port 11 into the internal space 20 (hereinafter also referred to as "air A"). Microparticles are viruses or bacteria, but may also be minute substances such as dust containing viruses or bacteria. Particulates may include microparticulate matter (PM2.5). PM2.5 refers to particles with a size of 2.5 μm or less among particles floating in the air.

The humidifier 40 is a mechanism that humidifies the air A flowing in the internal space 20, and increases the humidity of the air A. Specific examples of the humidification method of the humidifier 40 include a steam method (heating method), a vaporization method, a hybrid method (heating vaporization method), and an ultrasonic method, but the humidification method is not limited to these.

The collection device 50 collects charged fine particles from the air A flowing in the internal space 20 by electrostatic force. For example, when the collection device 50 has the ability to collect fine particles with a size of 10 nm or more and 100 μm or less, a small virus of about 30 nm, a novel coronavirus (COVID-19) of about 100 nm, or virus droplets of several μm. It can collect pathogenic bacteria. The size of fine particles that can be collected by the collecting device 50 is not particularly limited.

The discharge device 60 discharges the air A from the collection device 50 to the outlet 12 . The discharge device 60 introduces the air outside the air cleaner 100 into the internal space 20 through the suction port 11 and discharges the air A that has passed through the collection device 50 to the discharge port 12 . The discharge device 60 has, for example, a fan and a motor, and discharges the air A to the outlet 12 by rotating the fan with the motor.

The control device 80 operates or stops the charging device 30, the humidifying device 40, the collecting device 50, and the discharging device 60 according to the contents of the operation instruction from the user.

Thus, the air cleaner 100 includes the humidifying device 40 that humidifies the air A flowing in the internal space 20 . When ozone (O ₃ ) contained in air A and moisture (H ₂ O) contained in air A are mixed, hydroxyl radicals (OH radicals) that inactivate viruses or bacteria are generated. Therefore, by humidifying the air A with the humidifier 40, OH radicals can be generated, so viruses or bacteria contained in the air A and viruses or bacteria collected by the collection device 50 can be inactivated.

Viruses and bacteria are inactivated by ozone, but excessive ozone is harmful to the human body. Therefore, it is preferable to make the ozone concentration as small as possible. The air purifier 100 of the present embodiment can efficiently generate OH radicals that inactivate viruses or bacteria by humidifying the air A with the humidifier 40 even with a relatively small amount of ozone. Therefore, the air cleaner 100 can inactivate viruses or bacteria contained in the air A and viruses or bacteria collected by the collecting device 50 .

The charging device 30 may charge fine particles contained in the air A by corona discharge. Moisture contained in the air A humidified by the humidifier 40 readily reacts with ozone generated in the air A by corona discharge. Therefore, the air cleaner 100 can efficiently generate OH radicals that inactivate viruses or bacteria. As a result, the effect of inactivating the viruses or bacteria contained in the air A and the viruses or bacteria collected by the collecting device 50 is enhanced.

The ozone contained in the air A (which may include ozone generated by corona discharge) reacts with the moisture contained in the air A humidified by the humidifier 40 and is easily decomposed. As a result, the concentration of ozone contained in the air A is reduced, so that the discharge device 60 can discharge air having an ozone concentration of 0.1 ppm or less from the outlet 12 .

When the humidifier 40 humidifies the air A to a humidity of 67% or higher, the moisture contained in the humidified air A reacts with the ozone contained in the air A (which may include ozone generated by corona discharge). promotes. This increases the efficiency of generating OH radicals and further improves the effect of inactivating viruses or bacteria. The humidifier 40 preferably humidifies the air A to a humidity of 70% or more, more preferably 75% or more, in terms of increasing the efficiency of generating OH radicals (increasing the effect of inactivating viruses or bacteria). It is preferable, and it is more preferable to humidify to 80% or more.

The position of the humidifying device 40 is not particularly limited as long as it satisfies the desired humidifying function. In the example shown in FIG. 1 , the humidifying device 40 humidifies the gas A between the suction port 11 and the charging device 30 . As a result, the air A humidified by the humidifying device 40 is easily supplied to the charging device 30, so that the reaction between the moisture contained in the air A and ozone (which may include ozone generated by corona discharge) is further enhanced. Facilitate. As a result, the efficiency of generating OH radicals is increased, and the effect of inactivating viruses or bacteria is further improved.

The humidifying device 40 may humidify the air A passing through the charging device 30 . This further promotes the reaction between the moisture contained in the air A and ozone (which may include ozone generated by corona discharge). As a result, the efficiency of generating OH radicals is increased, and the effect of inactivating viruses is further improved.

The arrangement position of the collection device 50 is not particularly limited as long as it satisfies the desired collection function. In the example shown in FIG. 1 , the collecting device 50 collects charged fine particles from the air A by electrostatic force between the charging device 30 and the outlet 12 . As a result, the particles charged in the charging device 30 are more likely to be supplied to the collecting device 50, so that the capability of collecting the charged particles is improved. When the discharging device 60 is interposed between the charging device 30 and the outlet 12, the collecting device 50 collects the charged fine particles from the air A by electrostatic force between the charging device 30 and the discharging device 60. is preferred. This improves the ability to collect charged fine particles.

The placement position of the ejection device 60 is not particularly limited as long as it satisfies the desired ejection function. In the example shown in FIG. 1 , the discharge device 60 is arranged between the collection device 50 and the outlet 12 . Since the fine particles contained in the air A are collected by the collecting device 50, the discharging device 60 is disposed between the collecting device 50 and the blowout port 12, so that the discharging device 60 can collect the dirty air A. less likely to be polluted. As a result, for example, safety in maintenance such as replacement and cleaning of the discharging device 60 is improved.

The air purifier 100 may include a filter 90 for filtering ozone between the collecting device 50 and the outlet 12 . As a result, the effect of reducing the concentration of ozone contained in the air blown from the outlet 12 is enhanced. If the discharge device 60 is interposed between the collection device 50 and the outlet 12 , the filter 90 is preferably interposed between the discharge device 60 and the outlet 12 . As a result, the effect of reducing the concentration of ozone contained in the air blown from the outlet 12 is enhanced. By using, for example, manganese oxide as the catalyst of the filter 90, the effect of reducing the ozone concentration is improved.

FIG. 2 is a schematic diagram showing a first configuration example of the charging device in the air cleaner of one embodiment. A charging device 30A shown in FIG. 2 is an example of the charging device 30 described above. The charging device 30A has a discharge section 31 that generates corona discharge. The discharge part 31 has a discharge wire 32 arranged in the internal space 20 and

ground electrodes

33 and 34 facing the discharge wire 32 . The discharge wire 32 is an example of a discharge electrode. The ground electrode 34 is grounded at the same potential as the ground electrode 33 . The charging device 30A applies a high voltage HV1 between the discharge wire 32 and the

ground electrodes

33, 34 to generate corona discharge between the discharge wire 32 and the

ground electrodes

33, 34. FIG.

FIG. 3 is a schematic diagram showing a second configuration example of the charging device in the air cleaner of one embodiment. A charging device 30B shown in FIG. 3 is an example of the charging device 30 described above. The charging device 30B has a discharge section 36 that generates corona discharge. The discharge section 36 has a discharge electrode 37 arranged in the internal space 20, a ground electrode 38 facing the discharge electrode 37, and an insulator 39 for insulating between the discharge electrode 37 and a support section (inner wall, etc.).

The discharge electrode 37 is a disk-shaped electrode with a plurality of sharp projections extending radially. The discharge section 36 has a discharge electrode group 35 in which a plurality of discharge electrodes 37 are laminated with a space therebetween. A plurality of discharge electrode groups 35 are arranged in a plurality of spaces partitioned by grid-like ground electrodes 38 . The charging device 30B applies a high voltage HV1 between the discharge electrode 37 (the plurality of discharge electrode groups 35) and the ground electrode 38, thereby causing the discharge electrodes 37 (the plurality of discharge electrode groups 35) and the ground electrode 38 to A corona discharge is generated between

The discharge electrode of the charging device 30 (the discharge wire 32 in the case of FIG. 2, the discharge electrode 37 in the case of FIG. 3) may have a positive polarity or a negative polarity. The positive discharge electrode is an electrode to which a positive high voltage is applied with respect to the ground electrode, and the negative discharge electrode is an electrode to which a negative high voltage is applied with respect to the ground electrode.

The charging device 30 applies a positive high voltage HV1 between the ground electrode and the positive discharge electrode to generate corona discharge between the two electrodes, thereby suppressing the concentration of ozone in the internal space 20 and trapping the ozone. It is possible to improve the collection rate of fine particles in the collection device 50 .

FIG. 4 is a schematic diagram showing a configuration example of a collecting device in an air purifier according to one embodiment. A collection device 50A shown in FIG. 4 is an example of the collection device 50 described above. 50 A of collection apparatuses have the electric field generation part 51 which generates an electrostatic field. The electric field generator 51 has a high voltage electrode 54 arranged in the internal space 20 and

collection electrodes

52 and 53 facing the high voltage electrode 54 . High voltage electrode 54 is, for example, a conductive plate. The collection electrode 53 is grounded at the same potential as the collection electrode 53 . The collection device 50A applies a high voltage HV2 between the high voltage electrode 54 and the

collection electrodes

52, 53 to generate an electrostatic field between the high voltage electrode 54 and the

collection electrodes

52, 53. . As a result, the charged fine particles are attracted to the collecting

electrodes

52 and 53 by electrostatic force and adhere to the collecting

electrodes

52 and 53 .

FIG. 5 is a schematic diagram showing a first structural example of the air purifier of one embodiment. An air cleaner 100A shown in FIG. 5 is an example of the air cleaner 100 described above. The air cleaner 100A has a structure in which the discharge section 31 of the charging device and the electric field generation section 51 of the collection device are separated. The discharge line 32 and the high voltage electrode 54 are arranged in the air flow direction within the internal space 20 . The discharge device 60 discharges the air A in the internal space 20 to the outlet by rotating the fan 61 with a motor.

FIG. 6 is a schematic diagram showing a second structural example of the air purifier of one embodiment. An air cleaner 100B shown in FIG. 6 is an example of the air cleaner 100 described above. The air cleaner 100B has a structure in which the discharge section 31 of the charging device and the electric field generation section 51 of the collection device are integrated. The plurality of discharge lines 32 are arranged in the air flow direction within the internal space 20 . The discharge device 60 discharges the air A in the internal space 20 to the outlet by rotating the fan 61 with a motor.

Next, an example of the result of verifying whether or not the collected fine particles were inactivated for the air cleaner of one embodiment according to the present disclosure will be described.

FIG. 7 is a diagram showing an example of the verification result of the survival rate of bacteria before humidification (humidity of air A: 38% to 66%) at each position B1 to B6 in the internal space 20. FIG. FIG. 8 is a diagram showing an example of the verification result of the survival rate of bacteria after humidification (humidity of air A: 75% to 90%) at positions B1 to B6 in internal space 20. In FIG. 7 and 8 show an example of the verification result of the survival rate of bacteria arranged in the same number at positions B1 to B6 in the internal space 20 in the air purifier 100A (see FIG. 5). The survival rate on the vertical axis in FIGS. 7 and 8 indicates the ratio of the survival number of bacteria arranged at each position to the survival number of bacteria arranged at the position B0 on the most upstream side in the internal space 20. FIG. 7 and 8, "with electric field" indicates the case where the electric field generator 51 generates an electric field, and "without electric field" indicates the case where the electric field generator 51 does not generate the electric field.

The bacterium placed at each position B1 to B6 is Staphylococcus aureus NBRC13276. The processing conditions at the time of verification were as follows: flow velocity (wind speed) of air A in internal space 20: 0.5 m/s; processing time: 1 hour; humidity of air A: 90%; HV1 is -8.5 kV to 9.5 kV, and the high voltage HV2 applied in the electric field generator 51 is -5 kV.

According to Figures 7 and 8, a higher rate of inactivation of Staphylococcus aureus during humidification was obtained than Staphylococcus aureus before humidification. Thus, by humidifying the air A, the effect of inactivating the trapped bacteria was enhanced.

In addition, as shown in FIG. 8, by applying humidification, even without generating an electric field on the wall surface of the electric field generating section 51, the same degree of deactivation effect as when an electric field is generated was obtained. Therefore, it can be said that, by discharging corona discharge-treated humidified air indoors, viruses or bacteria adhering to surfaces such as walls, desks, or doorknobs can be inactivated without generating a high electric field.

The results shown in FIGS. 7 and 8 are examples when the ozone concentration in the internal space 20 is 1 ppm. and the same results as those with an electric field were obtained.

The above results were about the inactivation effect on Staphylococcus aureus, but the inactivation effect of corona discharge was also confirmed for viruses. The experimental apparatus is the same as in FIG. Escherichia coli phage MS2 was applied to each position B1 to B6 on the ground electrode and subjected to corona discharge treatment.

Fig. 9 shows the survival rate of MS2 at each application position after 5 hours of operation at a normal humidity of 22% to 28% and an ozone concentration of 8 ppm. Viability at each position B1-B6 was 70%-100% and could hardly be inactivated. On the other hand, FIG. 10 shows the survival rate when the relative humidity of the flowing gas is humidified to 75 to 90% and the corona discharge treatment is performed for 1 hour. The survival rate at each position B2 to B6 was 11 to 39%, and the virus could be inactivated at a low ozone concentration in a short period of time compared to the case of normal humidity in FIG.

Note that the position B1 is located upstream of the discharge line 32, and ozone and OH radicals do not reach it, so no deactivation effect is obtained. However, since the position B1 is located upstream of the discharge line 32, almost no floating fine particles are collected at the position B1 in the first place. Therefore, it does not pose a problem in practice. The MS2 used in the test is Escherichia coli phage, which is recommended by the Japan Electrical Manufacturers' Association standard JEM1467 and is known as a virus often used for alternative evaluation.

Next, for the air cleaner of one embodiment according to the present disclosure, an example of the result of verifying the characteristic change due to the difference in the polarity of the discharge electrode in the charging device will be described.

FIG. 11 is a diagram showing an example of the relationship between the applied voltage and the discharge current due to the different polarities of the discharge electrodes in the charging device. FIG. 12 is a diagram showing an example of the relationship between the discharge current and the ozone concentration depending on the difference in the polarity of the discharge electrode in the charging device. 11 and 12 show an example of the result of verifying the characteristic change due to the difference in polarity of the discharge wire 32 in the air cleaner 100A (see FIG. 5). 11 and 12 illustrate the case where the flow velocity (wind velocity) of the air A inside the internal space 20 is 9 m/s.

In FIG. 11, the voltage on the horizontal axis indicates the high voltage HV1 applied to the discharge wire 32, and the current on the vertical axis indicates the discharge current flowing through the discharge wire 32. According to FIG. 11, the high voltage HV1 applied to the discharge wire 32 is higher when the polarity of the discharge wire 32 is positive than when the polarity of the discharge wire 32 is negative. The higher the high voltage HV1 applied to the discharge wire 32, the higher the fine particle collection efficiency of the collection device 50. Therefore, by setting the polarity of the discharge wire 32 to the positive polarity, it is possible to improve the collection rate of fine particles in the collection device 50 .

On the other hand, in FIG. 12 , the current on the horizontal axis indicates the discharge current flowing through the discharge wire 32 , and the ozone concentration on the horizontal axis indicates the ozone concentration in the internal space 20 . According to FIG. 12, when the polarity of the discharge wire 32 is positive compared to negative, the ozone concentration is lower when compared with the same current. For example, when compared at a discharge current of 200 mA, the ozone concentration at positive polarity was about 1/8 of the ozone concentration at negative polarity. Therefore, by making the polarity of the discharge wire 32 positive, the ozone concentration in the internal space 20 was suppressed.

As described above, the higher the discharge current, the higher the ozone concentration, while the higher the voltage applied to the discharge wire, the higher the dust collection rate for collecting fine particles. Therefore, in order to secure a high dust collection rate while suppressing the ozone concentration, conditions of a small discharge current and a high applied voltage are effective. Therefore, according to FIGS. 11 and 12, by making the polarity of the discharge electrode in the charging device positive, the concentration of ozone in the internal space 20 is suppressed and the fine particle collection efficiency of the collection device 50 is improved. and becomes possible.

Although the embodiments have been described above, the present invention is not limited to the above embodiments. Various modifications and improvements such as combination or replacement with part or all of other embodiments are possible.

For example, the air cleaner may further include an irradiation device that irradiates the internal space 20 with ultraviolet rays that inactivate viruses. This further improves the effect of inactivating viruses.

This international application claims priority based on Japanese Patent Application No. 2021-023166 filed on February 17, 2021, and the entire content of Japanese Patent Application No. 2021-023166 is to refer to.

REFERENCE SIGNS LIST 10 housing 11 suction port 12 outlet 20

internal space

30, 30A, 30B charging device 31 discharge section 32

discharge wire

33, 34 ground electrode 35 discharge electrode group 36 discharge section 37 discharge electrode 38 ground electrode 39 insulator 40

humidifier

50, 50A collection device 51

electric field generator

52, 53 collection electrode 54 high voltage electrode 60 discharge device 61 fan 80 control device 90

filter

100, 100A, 100B air cleaner

Claims

an internal space interposed between the inlet and the outlet;
a charging device that charges fine particles contained in the air flowing from the suction port into the internal space;
a humidifying device for humidifying the air;
a collection device that collects charged fine particles from the air by electrostatic force;
and a discharge device that discharges the air from the collection device to the outlet.
The air purifier according to claim 1, wherein the charging device charges the fine particles by corona discharge.
The air cleaner according to claim 2, wherein the charging device has a ground electrode and a positive discharge electrode, and generates corona discharge between the ground electrode and the discharge electrode.
The air purifier according to any one of claims 1 to 3, wherein the humidifier humidifies the air to a humidity of 67% or higher.
The air cleaner according to any one of claims 1 to 4, wherein the humidifying device humidifies the air between the suction port and the charging device.
The air cleaner according to any one of claims 1 to 4, wherein the humidifying device humidifies the air passing through the charging device.
The air cleaner according to any one of claims 1 to 6, wherein the collecting device collects the fine particles between the charging device and the outlet.
The air purifier according to any one of claims 1 to 7, wherein the discharge device discharges air having an ozone concentration of 0.1 ppm or less from the outlet.
The air purifier according to any one of claims 1 to 8, comprising a filter for filtering ozone between said collection device and said outlet.