JP2002136579A - Air cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air cleaner having a safety and improving a reaction efficiency of a photocatalyst. SOLUTION: Since a light having a wavelength of 400 nm or less is emitted to the photocatalyst coated with an optical honeycomb 15 by lighting a light source 17, the photocatalyst is activated. Cells of the honeycomb 15 are decomposed or substituted to a harmless substance by an oxidation of a contaminant substance in the air during passing by an oxidizing decomposing action of an ozone and an oxidizing decomposing action of the photocatalyst. Since the cells are inclined at 45 deg. to the flow of the air, a contact reaction of the air with the photocatalyst or the like is effectively advanced in the air passing the cells of the honeycomb 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purifier for purifying by decomposing or converting pollutants in the air into harmless substances by the action of a photocatalyst. Such an air purifier is suitable for use in purifying air in a room, a car, a desk, a bed, a locker, a shoe box, and the like.

[0002]

2. Description of the Related Art In recent years, photocatalysts have been developed around the world for the purpose of antifouling, sterilization, deodorization, purification, etc. due to their strong oxidizing power. For photocatalysts such as titanium dioxide, 4
Irradiation of light having a wavelength of 00 nm or less, particularly light having a wavelength of 300 to 400 nm, generates electrons and holes on the surface, and causes an oxidation-reduction reaction. That is, O ₂ ^- and OH ^- are generated as the active species. Therefore, the photocatalyst is used in an air purifier or the like that oxidizes and decomposes pollutants by the oxidation-reduction reaction to purify air.

FIG. 4 is an exploded perspective view of a conventional air purifier using a photocatalyst. Air is introduced into the casing member 43 via the front case 41, and the filter 40,
It is discharged to the outside of the casing member 43 via a sirocco fan 45 and an optical honeycomb 47 which is a photocatalyst carrier having a honeycomb structure. A photocatalyst is carried on the surface of the base material of the optical honeycomb 47, and the photocatalyst is irradiated with ultraviolet rays from a light source 49. The contaminants introduced into the light honeycomb 47 and in contact with the photocatalyst are decomposed or converted into harmless substances by the oxidative decomposition action of the photocatalyst. An air purifier using a photocatalyst has a characteristic action of decomposing or replacing pollutants with harmless substances, instead of adsorbing and removing contaminants as in an air purifier using activated carbon. In addition, the activated carbon as an adsorbent needs to be replaced, but the photocatalyst does not need to be replaced and has an advantage that it can be used semi-permanently.

[0004]

However, in an air purifier using a photocatalyst, the rate of decomposition of pollutants due to the oxidative decomposition of titanium dioxide is slow. There was a problem that it could not be removed. Therefore, in order to increase the contact area between the air and the photocatalyst to improve the purification ability, a photocatalyst having a honeycomb structure and having a photocatalyst carried on the surface thereof has been proposed.

However, since the proposed honeycomb structure has a vertical cell structure, the contact reaction with air is not effective, and it is necessary to improve the contact reaction efficiency.
That is, it is necessary to improve the reaction efficiency of the photocatalyst and the durability (self-cleaning action) of the photocatalyst. Therefore, an object of the present invention is to provide an air purifier that is safe and has improved reaction efficiency of a photocatalyst.

[0006]

The air purifier of the present invention comprises:
A photocatalyst carrier in which a photocatalyst is carried on the surface of a substrate constituting the honeycomb structure; a light source for irradiating the photocatalyst carrier with light of a predetermined wavelength; a blowing unit for introducing air into the photocatalyst carrier; Ozone generating means for generating ozone from oxygen and an ozone decomposition catalyst for decomposing ozone are arranged in the casing member, and after the air introduced into the casing member passes through the ozone generating means and the photocatalyst carrier. An air purifier configured to pass through the ozonolysis catalyst and be discharged to the outside of the casing member, wherein the honeycomb structure or the ozonolysis catalyst has a honeycomb structure inclined in the direction of air flow. That is,
In order to make the contact reaction with air effective, the honeycomb structure or the ozone decomposition catalyst is inclined with respect to the flow direction of the air, so that the wind of the fan is not blown straight, but is blown after colliding with the honeycomb. Structure. A preferred inclination angle is 30 to 60 °, particularly preferably 45 °, in the flow direction of the air of the honeycomb structure or the ozonolysis catalyst.

[0007] Further, the honeycomb structure of the honeycomb structure and the honeycomb structure of the ozone decomposition catalyst are characterized by having 45 ° inclinations in opposite directions. As a result, the ozone decomposition effect is also improved, and the light is not visible from the outlet.
Light leakage can be prevented.

It has been confirmed by the present inventors that coexistence of ozone in the photocatalytic reaction promotes the oxidative decomposition reaction of pollutants. The effect is considered as follows. Oxidative decomposition reaction of active species generation by photocatalyst. ... The original photocatalytic purification action. Oxidative decomposition reaction by ozone. ... The high molecular components that cannot be decomposed by the photocatalyst are oxidized to low molecular components. However,
The oxidative decomposition reaction using ozone does not completely decompose into carbon dioxide and water, but often produces an intermediate, which is decomposed by a photocatalyst. Oxidation of reduced photocatalytic species by ozone.・ On the photocatalyst surface, not only the oxidizing action but also the reducing action proceed simultaneously, but when ozone coexists, the reduced species is oxidized.
The oxidation action of the photocatalyst is promoted. Ozone decomposition by photocatalyst. ... Use of ozone causes a problem of residual ozone in the air, but the photocatalyst decomposes ozone. At that time, active oxygen is generated, and the active oxygen also contributes to the oxidative decomposition reaction. The cleaning effect is improved by the above-described action. Further, ozone is decomposed by the action of the photocatalyst and the ozone decomposition catalyst, and active oxygen is generated at that time, and the active oxygen also contributes to the oxidative decomposition reaction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The light source is preferably a light source which emits light having a wavelength of 400 nm or less, preferably 200 nm or less and capable of generating ozone. For example, a low-pressure mercury lamp is used as the light source. When the air is irradiated with ultraviolet rays, the following reaction occurs, and oxygen atoms and ozone are generated in the air. O ₂ + UV (185 nm) → 2O O + O ₂ → O ₃ O ₃ + UV (254 nm) → O + O ₂ As described above, if a light source capable of generating ozone is used, it can also serve as an ozone generating means, thereby reducing the cost of the apparatus. In addition, downsizing can be achieved.

[0010] As another example of the ozone generating means, it is preferable to have a function of generating ozone and electrically collecting dust in the air. As a result, airborne particles in the air can be collected, and adhesion of the airborne particles to the blowing means and the photocatalyst carrier can be suppressed. As the ozone generating means, for example, there is an electric dust collecting electrode that charges suspended particles in the air by using discharge to collect dust. Although harmful components such as NOx may be generated by the action of the electrostatic precipitating electrode, the harmful substances are decomposed by the oxidative decomposition action of the photocatalyst. In this case, a lamp having no ozone generation function can be used as a light source.

It is preferable that activated carbon is further carried on the photocatalyst carrier. The presence of activated carbon in the photocatalyst carrier causes temporary storage of contaminants by activated carbon. Activated carbon attaches and removes contaminants in equilibrium with contaminants in the air. That is, at a high concentration at which the decomposition by the photocatalyst cannot follow, the contaminant is adsorbed, and when the concentration of the contaminant in the air decreases, the contaminant is desorbed, so that the cleaning ability can be improved. Further, since activated carbon decomposes ozone, it can also serve as an ozone decomposition catalyst.

The base material of the photocatalyst carrier is a honeycomb structure having a semicylindrical outer shape and a body portion having a plurality of through holes in a radial direction, and the light source is located at the center of the semicylindrical axis of the photocatalyst carrier. The light source is preferably a bar-shaped light source to be arranged. As a result, it is possible to irradiate light to all the holes of the honeycomb structure, thereby improving the cleaning ability and realizing the miniaturization of the photocatalyst carrier. Further, the honeycomb structure has an inclination in the air flow direction. Accordingly, the air is not blown straight out but is blown out after colliding with the honeycomb, and the reaction efficiency is improved. Further, the respective honeycomb structures of the honeycomb structure and the ozone decomposition catalyst may have a 45 ° inclination in opposite directions. As a result, the ozone decomposition effect is also improved, and the structure is such that light cannot be seen from the outlet, so that light leakage can be prevented.

[0013] It is preferable that a filter for removing dust contained in the air introduced into the casing member is further provided. As a result, suspended particles in the air introduced into the blowing means and the photocatalyst carrier can be removed, and adhesion of the suspended particles to the blowing means and the photocatalyst carrier can be suppressed.

Preferred examples of the photocatalyst include titanium dioxide alone or a mixture with another metal or metal oxide containing titanium dioxide as a main component. The base material of the photocatalyst carrier is preferably made of a nonwoven fabric in order to increase the surface area. A preferred example of the ozone decomposition catalyst is activated carbon.

[0015]

FIG. 1 is a block diagram showing one embodiment, and FIG.
1 is an exploded perspective view, and FIG. 1B is a perspective view showing an optical honeycomb, a net member, and a light source constituting the embodiment. Reference numeral 13 denotes a casing member, which includes a filter accommodating portion 13a for accommodating the filter 3, a fan accommodating portion 13b for accommodating the sirocco fan 5, and an optical honeycomb accommodating portion 13c for accommodating an optical honeycomb (photocatalyst carrier) described later. I have. The fan accommodating portion 13b has a disk-like outer shape, and a rectangular filter accommodating portion 13a is formed on one end surface 13d on the front side. The front surface of the filter housing 13a is open. An optical honeycomb housing 13c is formed on a side surface of the fan housing 13b along one side surface (upper surface) of the filter housing 13a. The front surface (the surface on the filter housing portion 13a side) of the optical honeycomb housing portion 13c is open, and a plurality of slits serving as air outlets are formed on the upper surface (the surface on the opposite side to the fan housing portion 13b). . Filter housing 1
The inside of 3a communicates with the inside of the optical honeycomb housing 13c via the inside of the fan housing 13b.

The filter 3 is housed in the filter housing 13a. As the filter 3, a filter in which a HEPA filter and an activated carbon filter were laminated before and after was used. The filter 3 is not limited to this, but may be any filter that collects suspended particles in the air to be sucked. The front surface of the filter housing 13 a of the casing member 13 and the front of the optical honeycomb housing 13 c are covered by the front case 1. In the front case 1, a plurality of slits are formed as air inlets at positions corresponding to the filter housing 13a, and a plurality of slits are formed as air outlets at positions corresponding to the optical honeycomb housing 13c. Air is sucked into the fan housing 13b from the filter housing 13a side, and the optical honeycomb housing 13
A sirocco fan 5 as a blowing means for discharging to the c side is accommodated.

An optical honeycomb 15 carrying titanium dioxide as a photocatalyst is disposed inside the optical honeycomb accommodating portion 13c and in a space above the filter accommodating portion 13a. The optical honeycomb 15 is formed of a nonwoven fabric, and after the outer shape is formed into a flat honeycomb structure, the honeycomb structure is formed into a semi-cylindrical shape having an outer peripheral radius of 50 mm. The thickness of the honeycomb 3 in the radial direction is 20 mm, and the length in the axial direction is 250 mm.

The body of the optical honeycomb 15 is formed with holes (cells) penetrating radially in the radial direction. The cells are densely arranged in both a semi-cylindrical axial and radial direction, with a pitch in the cylindrical axial direction of about 10 mm. The cell is shown in FIG.
Has a 45 ° slope with respect to the air flow as shown in FIG. FIG. 2 is a cross-sectional view of the cells of the optical honeycomb 15, and arrows in the drawing indicate the flow of air.

Activated carbon is carried on the nonwoven fabric constituting the optical honeycomb 15. Titanium dioxide as a photocatalyst is applied and carried on the surface of the activated carbon, and activated carbon and titanium dioxide are carried in layers. In the optical honeycomb 15, one of the two flat surfaces along the axial direction of the semi-cylinder is in contact with the outer surface of the upper side wall of the filter housing 13a, and the other flat surface is in the optical honeycomb housing 13c. , And is disposed to face the fan housing portion 13b.

Inside the optical honeycomb accommodating portion 13c, a rod-shaped cold cathode low-pressure mercury lamp (about 6
Watts) are arranged as light sources 17. An ozone decomposition honeycomb 19 carrying activated carbon as an ozone decomposition catalyst is also disposed inside the optical honeycomb accommodating portion 13c so as to cover the outer peripheral surface of the optical honeycomb 15. The base material of the ozonolysis honeycomb 19 is made of, for example, cellulose, urethane, polypropylene, or the like, and the pitch size of the base material is, for example, 0.1 to 10 mm. This honeycomb 19
May be the same as the base material of the optical honeycomb 15.

Next, the operation of this embodiment will be described. The power is turned on, the light source 17 is turned on, and the fan 5 is operated. By the action of the fan 5, the air around the front case 1 is introduced into the casing member 13 through the slit for the air inlet. The introduced air is introduced into the optical honeycomb accommodating portion 13c via the fan 5 after the suspended particles are collected by the filter 3. In the optical honeycomb accommodating portion 13c, the light source 17 is turned on to emit light having a wavelength of 185 nm, so that ozone is generated. further,
When the light source 17 is turned on, the photocatalyst applied to the optical honeycomb 15 is irradiated with light having a wavelength of 400 nm or less, so that the photocatalyst is activated. By the oxidative decomposition action of ozone and the oxidative decomposition action of the photocatalyst, pollutants in the air passing through the cells of the optical honeycomb 15 are oxidized and decomposed or replaced with harmless substances. It should be noted that the air passing through the cells of the optical honeycomb 15 is, as shown in FIG.
Since it is inclined at 5 °, the contact reaction between air and a photocatalyst or the like proceeds effectively.

The generated ozone is decomposed by the action of the photocatalyst supported on the light honeycomb 15 and the ozone decomposition honeycomb 19, and the ozone concentration in the air discharged outside the casing member 13 becomes 0.05 ppm or less, which is safe for the human body. .
When ozone is decomposed, active oxygen is generated, and the active oxygen also contributes to the oxidative decomposition reaction. When the concentration of the contaminants in the air is high, the contaminants are temporarily adsorbed on the activated carbon supported on the optical honeycomb 15 and the ozonolysis honeycomb 19 and then decomposed. The air thus purified is supplied to the front case 1 and the optical honeycomb accommodating section 13.
The air is discharged out of the casing member 13 through the slit for the air outlet of c.

In the above description, the inclination of the cells of the optical honeycomb 15 is set to 45 ° with respect to the flow of air as shown in FIG.
However, the present invention is not limited to this, and the ozonolysis honeycomb 19 carrying the ozonolysis catalyst may be similarly inclined at 45 °. Further, as shown in FIG. 3, the respective honeycomb structures of the optical honeycomb and the ozone decomposition catalyst may have a 45 ° inclination in mutually opposite directions. In FIG. 3, reference numeral 20 denotes an optical honeycomb, reference numeral 21 denotes an ozonolysis honeycomb, and arrows indicate the flow of air.

Further, the light source is not a cold-cathode low-pressure mercury lamp, but may be a black light that emits light having a wavelength of 300 to 400 nm. Further, a material that generates ozone simultaneously with activation of the photocatalyst may be used. In the embodiment shown in FIG. 1, an ozone decomposition honeycomb supporting activated carbon as an ozone decomposition catalyst is provided. Ozone generated in the apparatus is decomposed to a safe concentration by the action of the photocatalyst supported on the optical honeycomb and activated carbon. If possible, an ozonolysis honeycomb may not be provided. In that case, the ozone decomposition catalyst of the present invention is constituted by activated carbon supported on a light honeycomb. In the embodiment of FIG. 1, a sirocco fan is used as the blowing means, but the invention is not limited to this, and another blowing means such as an axial fan may be used.

[0025]

According to the air purifier of the present invention, the cleaning ability can be improved by the oxidative decomposition action of the photocatalyst and ozone, and the safety can be improved because ozone is decomposed by the photocatalyst and the ozone decomposition catalyst. it can. In addition, the honeycomb structure or the ozone decomposition catalyst is inclined with respect to the direction of air flow, so that the fan wind is not blown out straight, but is blown out after colliding with the honeycomb. Efficiency is improved. Further, since the honeycomb structure of the honeycomb structure and the honeycomb structure of the ozone decomposition catalyst have a 45 ° inclination in opposite directions to each other, the ozone decomposition effect is also improved, and the structure is such that light cannot be seen from the outlet, so that light leakage can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an air purifier of the present invention, in which (A) is an exploded perspective view, (B) is an optical honeycomb constituting the embodiment,
It is a perspective view showing an ozonolysis honeycomb and a light source. It is an exploded perspective view shown.

FIG. 2 is a sectional view of an optical honeycomb.

FIG. 3 is a cross-sectional view of an optical honeycomb and an ozonolysis honeycomb.

FIG. 4 is an exploded view of a conventional air purifier.

[Explanation of symbols]

 1: front case 3: filter 5: sirocco fan 13: casing member 15: light honeycomb (photocatalyst carrier) 17: light source 19: ozonolysis honeycomb

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) B01J 35/04 301 F24F 7/00 A F24F 7/00 B01D 53/36 CJF F term (reference) 4C080 AA09 BB01 BB02 HH05 JJ03 KK02 MM02 MM08 QQ17 4D048 AA12 AA22 AB01 AB03 BA05X BA07X BB02 CC25 EA01 4G069 AA03 AA08 BA04B BA08B BA48A BA48C CA01 CA07 CA10 CA11 CA16 DA06 EA09 EA10 EA19

Claims (3)

[Claims] 1. A photocatalyst carrier having a photocatalyst carried on a surface of a base material constituting a honeycomb structure, a light source for irradiating the photocatalyst carrier with light having a predetermined wavelength, and a blowing means for introducing air into the photocatalyst carrier. An ozone generating means for generating ozone from oxygen in the air, an ozone decomposition catalyst for decomposing ozone,
Are arranged in the casing member, and the air introduced into the casing member is configured to be discharged outside the casing member through the ozone decomposition catalyst after passing through the ozone generating means and the photocatalyst carrier. An air purifier characterized in that the honeycomb structure or the ozonolysis catalyst has a honeycomb structure inclined in the direction of air flow. 2. A honeycomb structure or an ozone decomposition catalyst comprising 4
2. The air purifier according to claim 1, wherein the air purifier has a honeycomb structure inclined at 5 degrees. 3. The air purifier according to claim 1, wherein each of the honeycomb structures of the honeycomb structure and the ozone decomposition catalyst has a 45 ° inclination in opposite directions.