JP2004113621A - Air purifying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for efficiently purifying (deodorizing and sterilizing) air to be cleaned by combining a photocatalyst, UV rays, and ozone. <P>SOLUTION: The photocatalyst which is obtained by forming a photocatalytic coating film on a board is arranged near an UV ray lamp. Air to be purified is introduced from an inlet with a fan, and purified by the photocatalyst. Then the air purified by the photocatalyst is discharged from a blow-out port. The air purifying apparatus also includes: an ozone generation means; and an ozone dissolving means. It is preferable that the ozone dissolving means does not come into contact with the air when the ozone is generated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air cleaning device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, in the production, cooking, and processing of food, ultraviolet sterilization has been widely used in manufacturing processes, clean rooms, and the like, including a circulating air germicidal lamp for sterilizing airborne bacteria as an environmental improvement of factories. This is because ultraviolet sterilization is less likely to alter the object, and the equipment is compact. On the other hand, ozone sterilization can sterilize places where ultraviolet rays cannot be sterilized or bacteria attached to various devices, but the range of use is limited because ozone is harmful to the human body.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide an apparatus for efficiently purifying (deodorizing / sterilizing) air to be purified by using a photocatalyst, ultraviolet rays and ozone in combination.
[0004]
[Means for Solving the Problems]
The gist of the present invention is that a photocatalyst having a photocatalyst coating film formed on a substrate is provided near an ultraviolet lamp, air to be cleaned is introduced from a suction port by a fan, and the photocatalyst is cleaned by the photocatalyst. Next, in an air cleaning device configured to discharge air purified by the photocatalyst from the outlet, providing ozone generating means; and providing ozone decomposing means near the inlet or the outlet. Characterized in an air purifying device, and more preferably,
A photocatalyst having a photocatalyst coating film formed on a substrate is provided in the vicinity of an ultraviolet lamp, air to be cleaned is introduced from a suction port by a fan, the photocatalyst is cleaned by a photocatalyst, and then a photocatalyst is discharged from an outlet. An ozone generating means; an ozone decomposing means provided in the vicinity of the inlet or the outlet; and an ozone decomposing means comprising ozone. Air purification characterized by being configured to be in contact with air to be cleaned by the photocatalyst or air purified by the photocatalyst when non-generation occurs, and not to contact the air when ozone is generated. In the chemical device.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
In the apparatus of the present invention, a photocatalyst having a photocatalyst coating film formed on a substrate is provided in proximity to an ultraviolet lamp, air to be cleaned is introduced from a suction port by a fan, and the photocatalyst is cleaned by the photocatalyst. Then, the air cleaned by the photocatalyst is discharged from the outlet. The air to be purified is not particularly limited, and examples thereof include factories for manufacturing, cooking and processing foods. More specifically, a container drying room, a stand-by cooler room, a set room, a preparation room, a garbage room, and the like for a carried-in foodstuff are mentioned. Furthermore, various facilities such as hospitals, research facilities, and sanitary facilities are also included.
[0006]
In the photocatalyst of the present invention, the substrate is preferably a metal. The metal is preferably selected from aluminum, titanium, magnesium, steel or stainless steel, with aluminum being particularly preferred. Aluminum, titanium or magnesium may be an alloy. For example, as an aluminum alloy, Al-Mg, Al-Mg-Si, Al-Cu-Mg-Mn, Al-Zn-Mg-Cu, etc., and as a magnesium alloy, Mg-Al, Mg-Al-Zn, Mg- Mn and the like. In the present invention, a coating film of a photocatalyst is formed on a substrate of such a metal, and it is preferable that the metal surface is coated with an insulating film before this formation. By this insulating coating, the electrons on the photocatalyst can be sufficiently exchanged without flowing to the metal side, so that the photolytic activity can be remarkably enhanced.
[0007]
This insulating coating treatment is preferably selected from anodic oxidation, chemical conversion treatment or glass coating treatment. For example, in the case of aluminum and titanium, a so-called anodic oxide film that forms an oxide film on a metal surface by immersing them in an aqueous electrolyte solution and subjecting them to anodic polarization is generally used. In the case of a steel sheet, electroplating or hot-dip plating, and furthermore, chemical conversion treatment with phosphoric acid and phosphate are common. Further, in the case of aluminum, a chemical film formation method (chemical conversion treatment) using a chemical agent may be adopted instead of anodic oxidation. As the chemical conversion treatment, a treatment mainly composed of chromic acid or chromic acid-phosphoric acid, that is, a chromate treatment film is preferable. Also in the case of magnesium, anodic oxidation and chemical conversion treatment can be applied.
[0008]
Further, a glass coating method in which sodium silicate (water glass) is applied to the surface of aluminum or the like and then sintered may be employed.
[0009]
In the case of stainless steel, an acid (preferably sodium dichromate) treatment (chemical conversion treatment) for oxidizing the surface to passivate the surface may be employed.
[0010]
The thickness of the insulating coating is not particularly limited, but is usually selected from about 0.1 to 1 μm.
[0011]
Examples of the photocatalyst in the present invention include metal oxides such as zirconium oxide, titanium oxide, zinc oxide, tungsten oxide, cadmium oxide, manganese oxide, and copper oxide; metals such as cadmium sulfide, zinc sulfide, indium sulfide, lead sulfide, and tungsten sulfide. Sulfides; organic polymers such as polyparaphenylene, polyaniline, and polythiophene; intercalation compounds obtained by adding various metal oxides to strontium titanate; and zirconium oxide and titanium oxide are preferable. Most preferably, by selecting zirconium oxide, an ultraviolet light having a relatively short wavelength can be used, so that an improved photocatalytic activity can be easily obtained. Titanium oxide may be any of an anatase, rutile or blockite type, but an anatase type is optimal from the viewpoint of catalytic activity and availability.
[0012]
The method of forming the coating film of the photocatalyst on the metal substrate itself can be a conventional method, but a method of depositing from a liquid phase and a method of depositing from a gas phase are preferable. For example, the liquid phase method includes a sol-gel method and the like, and the gas phase method includes a chemical method such as a physical vapor deposition method (PVD) such as sputtering and vacuum vapor deposition or a gas phase chemical reaction method (CVD). The sol-gel method is optimal from the viewpoint of uniformity of coating to be obtained, cost and the like. As a starting material in the sol-gel method, a metal organic compound such as a metal alkoxide, a metal acetylacetonate, or a metal carboxylate, for example, a metal inorganic compound such as an oxychloride, a chloride, or a nitrate is generally used. Among these, metal alkoxides are preferable from the viewpoint of reactivity and the like. Metal alkoxides such as butoxide, ethoxide and propoxide (for example, zirconium or titanium) are used as a solution using a solvent such as butanol or propanol, and this is converted to a metal. A desired coating film can be formed by applying the composition to a substrate. For application, brushing, roll coating, dipping, spraying, spinning, or the like can be appropriately selected. The thickness of the coating film is generally selected from the range of 3 to 500 μm, preferably about 5 to 20 μm. For example, a substrate is immersed in a metal alkoxide solution using a sol-gel method, and is lifted to obtain a coating film. The coating film is dried by a conventional method, for example, at room temperature, and then heated to about 300 to 550 ° C. and fixed to the substrate. As the above-mentioned CVD method, a plasma CVD method can be used for forming a film by a gas phase chemical reaction in a relatively low temperature range of about 400 to 500 ° C., and thus there is no limitation on the base material, which is suitable.
[0013]
The obtained coating film forming substrate is then processed into a three-dimensional structure. This structure comprises a honeycomb, a corrugated sheet and / or a flat sheet. The honeycomb is not limited to a hexagonal core and may have any shape. The corrugated plate may be used in combination with a flat plate (corrugation) and arranged in parallel, or may be rolled up to form a honeycomb. The flat plates are preferably arranged in parallel and used as a so-called parallel passage type. The structure of the present invention enables efficient photocatalytic reaction because of extremely low airflow resistance. The processing for forming the three-dimensional structure is bonding, cutting, or cutting, and can be performed by an ordinary method. At the time of bonding, an organic adhesive is likely to be degraded by a photocatalyst, so that an inorganic adhesive is preferably used. Examples of such inorganic adhesives include glass based materials such as low melting point glass; metal based materials such as soft solder such as Sn-In, Bi-Pb, Sn-Pb and Pb-Sb; alkali silicate (particularly water glass); Other inorganic materials such as phosphates and the like can be mentioned, and those having an adhesion temperature of 100 to 500 ° C, preferably 120 to 200 ° C, are particularly preferable. Of these inorganic adhesives, the most preferred is water glass.
[0014]
The photocatalyst according to the present invention preferably has a surface roughness of 50 nm Ra (center line roughness) or less. When the mirror surface is formed and the coating film is transparent, the light reflectance is remarkable. Thus, for example, the inside of the honeycomb photocatalyst body can be irradiated with ultraviolet rays with irregular reflection, and the catalytic activity can be significantly improved.
[0015]
In the present invention, an ultraviolet lamp is provided close to the photocatalyst. Ultraviolet rays used for ultraviolet lamp irradiation include, for example, ultraviolet rays having wavelengths of 185 nm, 254 nm, and 300 to 400 nm. The wavelength of photoexcitation of the photocatalyst varies depending on the type of photocatalyst. For example, in the case of titanium dioxide, it is 380 nm or less for anatase type and 415 nm or less for rutile type, and further, it is 254 nm or less for zirconium oxide. As a lamp that emits such a light beam, a discharge lamp such as a black light, a low-pressure, medium-pressure or high-pressure mercury lamp is preferable.
[0016]
In the air cleaning device of the present invention, an ozone generating means is further provided. As the ozone generating means, an ozone lamp or silent discharge is suitable, and more preferably, a mercury lamp which generates ultraviolet light having a wavelength of about 185 nm is selected as the ozone lamp. The location is preferably near the UV lamp. It is preferable to generate ozone periodically. For example, a method in which ozone is generated intermittently at all times during the night and at a fixed time during the day may be selected depending on the purpose.
[0017]
Further, an ozone decomposing means for decomposing the remaining ozone is provided near the inlet or the outlet. As the ozonolysis means, an ozonolysis catalyst such as manganese dioxide is suitable.
[0018]
In a preferred embodiment, in the air cleaning apparatus of the present invention, when ozone is not generated, the ozone decomposing means comes into contact with air to be cleaned by a photocatalyst when provided near the suction port. Thus, on the other hand, when it is provided in the vicinity of the outlet, it has a configuration capable of contacting air cleaned by the photocatalyst. On the other hand, when ozone is generated, it has a configuration that can prevent the ozone from coming into contact with the air.
[0019]
To achieve such a configuration, in the first preferred embodiment, the air to be cleaned by the photocatalyst or the flow path of the air cleaned by the photocatalyst contacts the ozone decomposing means when ozone is not generated. And so that the air does not come into contact with the ozonolysis means when ozone is generated. The switching of the flow path can be performed manually or automatically by a switching damper, a switching valve, or the like based on a timer or an ozone monitor.
[0020]
Further, in a preferred second embodiment, the ozone decomposing means is placed in a flow path of air to be cleaned by the photocatalyst or air purified by the photocatalyst when ozone is not generated, and Sometimes it can be moved to be placed outside the flow path of the air to be cleaned by the photocatalyst or the air cleaned by the photocatalyst. Such a moving method is not particularly limited. For example, the moving method may be configured such that one end of the ozone catalyst body layer is rotated by 90 degrees around the axis and placed in the channel. This movement can also be performed manually or automatically based on a timer or an ozone monitor.
[0021]
In the air purifying apparatus of the present invention, since the air in the processing chamber space to be cleaned is circulated and introduced by the fan, it is suitable for compact and highly efficient deodorization and sterilization. The cleaning device is provided in an indoor space including indoor air to be cleaned, and for example, a ceiling and a wall portion are preferable.
[0022]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
Reference Example 1 Al plate - anodic oxidation / ZrO ₂ / sol - gel / honeycomb (hoisting corrugated)
An aluminum (Al) substrate (flat plate and corrugated plate) was anodized under the following conditions.
[0023]
・ Bath composition 13.7% sulfuric acid
Treatment conditions: about 22 ° C., 0.5 A / dm ² , DC, 5 minutes, cathode: carbon: Anodized aluminum oxide substrate (oxide film thickness: about 0.5 μm) obtained from zirconium butoxide in ethanol solution (zirconium butoxide 20 g) Immersion in ethanol, 45 g, water 20 g, hydrochloric acid 0.3 g), pulling up, drying (room temperature) repeatedly, and then firing (about 500 ° C.) to produce a ZrO ₂ coating film (about 50 nm Ra or less) having a thickness of about 10 μm. did. Then, a flat plate and a corrugated plate were combined and corrugated from the obtained anodic oxide film / ZrO ₂ coating film / aluminum substrate using a water glass adhesive, and this was rolled up in a honeycomb shape to obtain a honeycomb photocatalyst. .
Reference Example 2 Al plate - anodic oxidation / TiO ₂ / sol - gel / honeycomb (hoisting corrugated)
A honeycomb photocatalyst was obtained in the same manner as in Reference Example 1, except that a TiO ₂ coating film (about 10 μm in thickness) was formed instead of the ZrO ₂ coating film. An ethanol solution of titanium isopropoxide (25 g of titanium isopropoxide, 40 g of ethanol, 25 g of water, 0.3 g of hydrochloric acid) was used.
Example 1
One embodiment of an air cleaning device including the honeycomb photocatalyst (1) obtained in Reference Example 1 is shown in FIG. In FIG. 1, (2) shows two ultraviolet lamps, one of which is an ozone lamp. (3) shows a fan, (4) shows an inverter, (5) shows an operation panel, and (6) shows a power supply box. This air purifying device is mounted on the wall surface of a container drying room (indoor capacity 75 m ³ ) of a food processing facility, and the room air is circulated and introduced from a suction port (not shown) by a fan (3), and an air outlet (not shown). ), Air purification was performed continuously by a timer control once, three times a day for two hours, and ozone intermittently (process air volume: 12.5 m ³ / min). The air circulation frequency was 10 times / hour. When the number of airborne bacteria after 10 hours was measured by an air sampler method, the number of airborne bacteria was one tenth or less before the treatment.
[0024]
【The invention's effect】
The present invention can provide an apparatus for efficiently purifying (deodorizing / sterilizing) air to be purified by using a photocatalyst, ultraviolet rays and ozone in combination.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing one embodiment of the device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Photocatalyst 2 ... UV lamp 3 ... Fan

Claims (16)

A photocatalyst having a photocatalyst coating film formed on a substrate is provided in the vicinity of an ultraviolet lamp, air to be cleaned is introduced from a suction port by a fan, the photocatalyst is cleaned by a photocatalyst, and then a photocatalyst is discharged from an outlet. An air purifying device configured to discharge the air purified by
An air purifying device, comprising: ozone generating means; and ozone decomposing means provided near the inlet or the outlet. A photocatalyst having a photocatalyst coating film formed on a substrate is provided in the vicinity of an ultraviolet lamp, air to be cleaned is introduced from a suction port by a fan, the photocatalyst is cleaned by a photocatalyst, and then a photocatalyst is discharged from an outlet. An air purifying device configured to discharge the air purified by
Providing ozone generating means;
Providing ozone decomposing means in the vicinity of the inlet or outlet; and the ozone decomposing means so as to be in contact with air to be cleaned by the photocatalyst or air purified by the photocatalyst when no ozone is generated. An air purifying apparatus having a configuration capable of preventing contact with the air when ozone is generated. 3. The air cleaning device according to claim 1, wherein the ozone generating means is an ozone lamp or a silent discharge. The air to be cleaned by the photocatalyst or the flow path of the air cleaned by the photocatalyst is configured to be in contact with the ozone decomposing means when no ozone is generated, and not to be in contact with the air ozone decomposing means when ozone is generated. The air purifying device according to claim 2 or 3, wherein the air purifying device can be switched to: 5. The air purifying apparatus according to claim 4, wherein the switching is performed manually or automatically based on a timer or an ozone monitor. The ozone decomposing means is placed in the flow path of the air to be cleaned by the photocatalyst when no ozone is generated or the air to be cleaned by the photocatalyst when ozone is generated. 4. The air purifying apparatus according to claim 2, wherein the air purifying apparatus can be moved so as to be placed outside a flow path of the air cleaned by the photocatalyst. The air cleaning apparatus according to claim 6, wherein the movement is performed manually or automatically based on a timer or an ozone monitor. The air purifier according to any one of claims 1 to 7, wherein the ozonolysis means is an ozone catalyst. The air purifying apparatus according to any one of claims 1 to 8, wherein air to be cleaned is circulated and introduced. 3. The air cleaning device according to claim 1, wherein the substrate is a metal. The air cleaning device according to claim 10, wherein the metal is aluminum, titanium, magnesium, steel, or stainless steel. The air cleaning device according to claim 10 or 11, wherein the metal is coated with an insulating material selected from anodic oxidation, chemical conversion treatment, and glass coating treatment. 3. The air cleaning device according to claim 1, wherein the photocatalyst is zirconium oxide or titanium oxide. 3. The air cleaning device according to claim 1, wherein the thickness of the coating film is 3 to 500 [mu] m. 3. The air cleaning device according to claim 1, wherein the coating film is formed by a sol-gel method. 3. The air cleaning apparatus according to claim 1, wherein the catalyst body is formed of a honeycomb, a corrugated plate, and / or a flat plate.

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