JPH11505746A - Tabletop UV activated odor filter - Google Patents

Abstract

The present invention relates to an apparatus for purifying air with an activated photocatalyst such as titanium dioxide. The device comprises a housing (1) having an inlet (2) and an outlet (4) for circulating air, and circulating means (5), such as a blower, mounted in the housing for circulating air. A planar filter (7) arranged to intersect with the circulating air flow path, the filter including a photocatalyst fixed to a fibrous porous support, and a filter inside the housing for activating the photocatalyst. And a light source (13) attached to the light source. The present invention provides a compact device that can be easily mounted on a desktop or laboratory desk and that can rapidly reduce levitating contaminants, such as odors.

Description

DETAILED DESCRIPTION OF THE INVENTION Tabletop UV activated odor filter Technical field   The present invention is directed to an apparatus and method for removing odor or levitating contaminants from air. About the law. Background art   Air in the enclosed space may be volatile organic compounds, molds and inorganic compounds. It becomes stale and odorous due to contamination by foreign substances. In hospital, for anesthesia Accumulation of gases and toxic sterilizing compounds, such as ethylene oxide, in the air become. In confined spaces such as cars, trucks and aircraft interiors, For example, the accumulation of contaminants from building materials or interior equipment may be even more problematic. U. Burning tobacco also contributes to pollution.   Treatment of contaminated air involves the removal of solid particles, such as filtration, adsorption on activated carbon, Alternatively, the focus has been on the removal of solid particles by electrostatic precipitating. Such a solid Removal only moves contaminants from one location to another. like this In the case of activated carbon, which is generally selected for efficient removal, the pollutants eventually become saturated and Adsorbs on the surface of activated carbon that must be replaced. Some contaminants have low molecular weight Such as gaseous compounds that do not adsorb until saturated or are easily desorbed There is. Furthermore, the efficiency of pollutant removal decreases at high temperatures.   Some of the many requirements for air purifiers are fundamentally important, This has not been achieved with commercially available equipment. These requirements are at room temperature and The ability to handle various contaminants simultaneously under prolonged operation.   Recently, photocatalysts have been used to remove contaminants. Contaminated air is a good light source Pass through or through the photocatalyst that is irradiated. Titanium dioxide in anatase form (T iO_Two) Is a general type of photocatalyst, which is suitably irradiated with ultraviolet light at room temperature. titanium dioxide Photocatalytic treatment using low-molecular-weight organic gas compounds and inorganic gas compounds Process removes activated carbon faster than active carbon, and pollutants are harmless, odorless or more toxic It has the advantage that it is almost completely decomposed into compounds having low properties.   U.S. Pat. No. 5,045,288 (Raupp et al.) Discloses the use of photocatalysts from water. An apparatus for removing contaminants is disclosed. Water is UV permeable to the reactor It is pumped to the photocatalyst bed, which is irradiated through the wall. Such a device It can be improved to use air instead of air, but the catalyst bed and loosely stuck catalyst For large reaction chambers required for such applications, such devices are used in small spaces such as rooms. Make things inappropriate. In addition, the back pressure or resistance created by the catalyst is Strong attachment for efficient removal of contaminants by preventing air treatment Will need.   U.S. Pat. No. 4,892,712 (Robertson et al.) Discloses photocatalysts. An apparatus for use in removing contaminants from a fluid is disclosed. The device is ultraviolet The tube is surrounded by a cylindrical substrate containing the photocatalyst. The UV tube and the substrate, in order, are liquid Inside the cylindrical jacket that does not leak The jacket is a small fluid perpendicular to the longitudinal axis of the cylindrical jacket. An inlet tube is provided at one end of the device and a corresponding fluid outlet tube is provided at the other end of the device. I do. Although the device is described as being useful for both gases and liquids, Not effective for rapid removal of contaminants from room or laboratory air U. The back pressure generated by air moving along the length of the substrate It would require an inconvenient size for the blower.   Rooms in hospitals, houses, or laboratories, or cars, trucks or airplanes Suitable for removing contamination and removing odors from small spaces such as the interior of vehicles Equipment is required. Purifiers are not too large to be suitable for smaller spaces Or it should be able to process large volumes of air quickly without being too bulky. That Such devices can be placed on a table or tabletop to quickly remove unpleasant or harmful contaminants. Preferably. Disclosure of the invention   According to one aspect of the present invention, there is provided an air purification device having an air inlet and an air outlet. Housing and   Air flows from outside the housing, through the inlet, and along the air flow path in the housing. Circulating means mounted in the housing for circulating out of the outlet When,   Flat filtration means intersected with the circulating air flow path. Filtration means comprising a photocatalyst fixed to the porous support,   Mounted in the housing to direct light onto the filtering means and activate the photocatalyst A light source. BRIEF DESCRIPTION OF THE FIGURES   The invention will be described with reference to the accompanying drawings, which show, by way of example, specific examples of the invention and its components. This will be described below.   FIG. 1 is a schematic side view, partially broken away, of a device according to the invention;   FIG. 2 is a front view of the specific example of FIG.   FIG. 3 is a partially cut-away schematic side view as in FIG. 1, but in an open position. The back of the reciprocating opening and closing type   FIG. 4 shows a filter car including a filter suitable for use in the apparatus of FIG. FIG.   5 and 6 are a front view and a side view of the filter cartridge of FIG. 4, respectively. Yes,   FIGS. 7, 8 and 9 show different filters suitable for use in the apparatus of FIG. It is an exploded view of a specific example. BEST MODE FOR CARRYING OUT THE INVENTION   In a preferred embodiment, the air flow path includes an upstream portion where air flows in one direction, Having an adjacent downstream portion flowing in opposite directions, the flat filtering means comprising an upstream portion and a lower portion. It is located within the housing to extend across the flow.   The housing is a passage for air circulation, as well as other elements, such as a light source And a structure to which the circulation means can be attached. Housing is plastic Or metal or other suitable structural material. Except for the entrance and exit, The housing should be reasonably airtight Must have.   The inlet should be large enough to accommodate the filtering means. If the entrance is a filter Above that, air would be passed through without exposure to the photocatalyst. Also If the inlet is smaller than the filtration means, some of the available area of the filter will be wasted. Will be. The dimensions of the filtering means are large enough to allow a suitable air flow. Should be quick. The air inlet is upstream of the photocatalytic filtration means, additional filtration means, e.g. For example, even if it has filtering means used in a furnace to remove dust and prevent clogging of the photocatalyst Good.   Air flows through the filtration means as quickly as it passes through an unobstructed outlet of the same size. Because they cannot pass through, the exit is made smaller than the entrance to equalize the system. It may be unified. In the tested device, a dimensional difference of 33% was used (the inlet was 0.31 m^Two (48 square inches) with 0.23m exit^Two(36 square inches).   Preferably, the protective grille is located outside the entrance and the exit. lattice Must not substantially interfere with the airflow.   The light source should emit light of sufficient intensity and wavelength to cause the reaction or decomposition of the contaminants. It should be supplied to activate the photocatalyst. A wide range of light sources can be used. Good Suitable light sources include fluorescent UV lamps, incandescent UV lamps, xenon lamps, as well as low, medium and And high pressure mercury lamps. However, if the photocatalyst is titanium dioxide Ultraviolet light sources, for example, dark light having a wavelength band of 300 nm to 440 nm are preferable. Good. Short wavelengths, such as wavelengths of about 254 nm, have been found to be efficient. However, for safety reasons, use light in the UV A area. Preferably. A wavelength band of about 350-380 nm is preferred. 366 nm Wavelength is more preferred.   The light intensity depends on the type and number of light sources. For titanium dioxide Low power 15 watt mercury bulb with peak power at 313 nm and 366 nm wavelength Has proven to be sufficient. Such bulbs bring safety and economy . When using such a bulb, if you use two bulbs instead of one, Significant increase in reaction rate (contaminant reduction as a function of time) But the gains obtained using three bulbs instead of two are not so great I know. Therefore, two bulbs are preferred for home use for economy. Would.   The light source is located on one side of the filtering means. That is, the light source is surrounded by the filtering means. Absent. This allows the filtering means to have a larger area in the air flow path, Light from the light source is emitted and reaches the exposed surface of the filtering means. Place reflective layer behind light source It is preferable that the escaping light be reflected back to the filtering means.   Any photocatalyst that effectively reduces or removes contaminants may be used. Suitable touch The medium is TiO_Two, ZnO, CdS, WO_Three, SnO_Two, ZrO_Two, Sb_TwoO_Four, CeO_TwoAnd Fe_TwoO_ThreeIt is. A more preferred photocatalyst is TiO_TwoAnatase form of You.   Optimization of odor or pollutant removal will increase efficiency on the one hand and increase air Conflicts such as increasing flow rates and reducing costs It will be a balance between demands. For a given photocatalyst, the efficiency of pollutant removal is Light intensity and wavelength; photocatalytic surface area; volumetric air flow; Affected by differential pressure across.   The flow rate determines the residence time or the time that the contaminant contacts the photocatalyst. To the residence time The longer the polluted air makes contact with the photocatalyst, the more likely it is that the pollutants will decompose. The rate will be high. On the other hand, treating as much air as possible It is desirable to reduce the quantity of quality.   As the circulation means, means other than a blower, for example, a pump or convection may be used. A blower is convenient. The circulating means can only move air reliably over the photocatalyst. Has been requested.   In a preferred embodiment, the entrance is on one side of the housing, the front top. The outlet is at the end of the tunnel protruding from the bottom on the same side of the housing. this The tunnel provides a convenient location for the blower, and the footprint of the device (footprint) ) To provide stability to the device so that the device does not easily fall over . Such a design also allows the filter to extend to substantially the full height of the device. Enables a more preferred structure that can be made. The incoming air then flows to the top of the filter Exposed to the compartment, guided around the U-turn by the curved shape of the back of the housing And then again on the bottom section of the filter on the way to the exit through the tunnel Exposure to photocatalyst. The device uses a compartment to filter the top and bottom compartments. Divide into sections.   Other arrangements are of course possible. For example, if circulating air is on one side of the housing From the inlet of the housing to the outlet on the other side of the housing in an essentially straight flow path Zing can also be built. In such an arrangement the housing is rectangular May be advantageous. Filtration means adjacent to either inlet or outlet It is also possible to mount it at the inlet and outlet using two filtration means. It is also possible to position them adjacent to each other. Then, circulating means for the inlet and outlet It is possible to arrange them in the middle between them. It can be seen that various arrangements are possible It will be.   The filtering means includes a flat or pleated filter. Filter is a book Qualitatively, it comprises two components: a support and a photocatalyst. The support is fibrous and It should be porous enough to allow for moderate flow rates. The support has a large surface area It is preferred that it has, is transparent to, or absorbs little of, the light used. No. The photocatalyst is placed on the support to maximize the surface area exposed to circulating air. Should be placed. The photocatalyst is prepared by using a support prepared by a usual method in a liquid medium. The coating on the support is brought into contact by contact with the photocatalytic coating composition. It can be in the form. An effective way to maximize surface area is to use photocatalyst particles. A fibrous non-woven support capable of electrostatically holding the To apply the photocatalyst to the material in the form of fine powder. Pre-charged elect The let fiber is a dielectric polymer that can be corona discharged and then fibrillated. It is preferably formed from a mer film.   Suitable film-forming dielectric polymers are polyolefins, such as polypropylene. , Linear low density polyethylene, poly-1-butene, polyethylene Trafluoroethylene, polytrifluorochloroethylene; or polyvinyl chloride Aromatic polyarenes such as polystyrene; polycarbonates; And their copolymers and mixtures thereof. Branched alkyl radical Cal-free polyolefins and their copolymers are preferred. Polypropylene and And polypropylene copolymers are particularly preferred.   Various functional additives known in the art, for example, US Pat. No. 4,874,399 (4-Methyl-1-pentene) as taught in U.S. Pat. No. 4,789,5 No. 4,456,648 or fatty acid metal salts as disclosed in US Pat. Such particles can be incorporated into a dielectric polymer or copolymer. Such an d The lectret fibers will electrostatically fix the particles. Blown fiber, especially Blown polypropylene microfibers are preferred as the support material. Fibrous support Is 20 grams / m^TwoFrom 80g / m^TwoWeight in the range of Ram / m^TwoFrom 60g / m^TwoBe a polypropylene having a weight in the range of More preferred.   The preferred support material, blown polypropylene microfibers, is as a roll Commercially available, compressed 0.127 mm (5/1000 inch), uncompressed Has a thickness of 0.508 mm (20/1000 inches). For the present invention The material is "fluffed" to an uncompressed thickness of 1.524 mm (60/100 0 inches). This material is filled with photocatalyst and then double or triple It is preferably used as an overlay.   The filtering means, in which the photocatalyst is electrostatically fixed to the support, The catalyst powder is brought into contact with the support, and the loosely attached particles or excess particles are decompressed. It is easily adjusted by removing.   In addition, the powdery photocatalyst is coated with, for example, a thin aqueous acrylic adhesive as a support. And then contacting the coated support with the photocatalytic powder. The carrier can also be filled. Titanium dioxide uses this technology to make polypropylene The support can be filled.   The photocatalytic powder should generally have particles with a size of less than 1 mm, otherwise The support may not be able to hold the particles electrostatically. In addition, smaller particles The dimensions usually result in a larger surface area, thereby increasing the reaction rate. There will be. A particle size of 1 nm to 1 mm (1000 microns) is preferred, And a range of 1000 mm is preferable.   Filters are generally at least 1m^Two/ g, preferably at least 5 m^Two/ g It should provide the surface area of the photocatalyst. The photocatalyst is in powder form, and When electrically fixed, substantially all surface area of the photocatalyst is available for the reaction . Suitable powdered titanium dioxide photocatalysts are available under the trade name "P25" from Degus. sa), which is about 50m^Two/ g surface area and UV Available from Hombicat under 100, it is about 250m^Two/ g surface area. However, if the particles are extremely fine, they will It should be noted that the expected surface area may be reduced as a result of the aggregation.   Coating a composition of titanium dioxide photocatalyst on a support in a liquid medium Is typically about 10 m^Twoabout 15m / g^Two/ g table Will have an area.   The use of a powdered photocatalyst electrostatically bonded to a fibrous support results in the weight of the support. Up to 50% by weight of the photocatalyst can be loaded on the support, based on the amount. Preferred The filling range is 10% to 25% by weight.   The use of activated photocatalysts such as titanium dioxide allows both organic and inorganic compounds Can be disassembled. For example, hydrocarbons can be broken down into carbon dioxide and water, Element can be decomposed into elemental sulfur. The reactions that occur do not consume the photocatalyst, which is It can be reactivated continuously.   The filtration means further comprises a layer of adsorbent, such as activated carbon, which is at least one other fibrous Contaminants from a combination of photocatalyst and adsorbent, including on a porous support layer of The benefit of reduction or elimination can be obtained. When using such additional layers, To avoid blocking light and hindering the activation of the photocatalyst, the additional layer is It should be located on the side facing the light source.   Back pressure is generated during operation of the device because the filtration means is placed across the circulation air passage I do. Back pressure is a function of the pressure drop across the filter. For example, home warmth In a chamber furnace, the pressure drop across the filter is 1.524 m / s (300 ft / min) At a surface velocity of about 0.15 inches (3.81 mm). Such a home warm In the cellar, Water drop at a pressure drop across the filter of 300 feet / minute (1.524 m / s) If it rises to 2.7 mm (0.15 inch), the blower will circulate the air Will not have enough power.   For tabletop or bench-top applications, such as those preferred for the device of the present invention, a filter The pressure drop across is preferably a surface velocity of 0.381 m / s (75 ft / min) In the range of water from 7.62mm to 12.7mm (0.3 inch to 0.5 inch), 25 to 15.24 mm water at a surface speed of 1.524 m / s (300 ft / min) . It should be in the range of 4 mm (0.6 inch to 1.0 inch). Ideally The pressure drop should be as low as possible for a given flow rate, Consistent with achieving efficient contact between the air and the photocatalyst.   Preferably, the air flow rate is from 0.0508 m / s to 3.556 m / s (1 0 ft / min to 700 ft / min), more preferably 0.127 m / s to 1.778 m / s (25 to 350 ft / min) is there.   When using the preferred polypropylene support material, 3.04 for the bilayer From about 8 mm (120/1000 inches) to about 3 layers for compressed triple or multiple layers. Thicknesses up to 302 mm (130/1000 inches) are preferred.   The support is preferably pleated or corrugated. This pleated structure is back pressure Larger surface area without significant increase in airflow or obstruction of airflow . To assist in the construction of such pleated structures, the support must be shaped as desired. Structured to hold Can be mounted on the backing material where possible. Back surface material is air flow and light touch It should not interfere with the activity of the medium. Stretched metal or scrim (cotton cloth) is the backing material It is suitable as a material. A scrim is a mesh of material such as polypropylene, For example, available from Conwed Corp. Commercially available Some scrim configurations have a thickness of 0.254 mm (10/10000 inches) . The backing layer may be coated with a layer of pressure sensitive adhesive to hold the support. The filtering means may comprise a multi-layer support, for example, a support layer on each of a plurality of back layers. Also, one back side connects the support layer to each side so that the back side layer is effectively between the support layers. May be included. Of course, having more layers would impede airflow. Single layer or double layer pleated is preferred.   The equipment is equipped with various odors and contaminants such as isobutane, propane, diethyl Low molecular weight organic gases such as ether and acetaldehyde, and propion Ethyl acid (smelling rum like fruit), Allyl butyrate (smell of peach and apricot) ) And high molecular weight gases such as propyl butyrate (acid odor like sweat) Can be used for An important pollutant that can be removed is hydrogen sulfide It is. It is said that 80% of the malodorous gas contains hydrogen sulfide.   With reference to FIG. 1, an air purification device according to the invention has a substantially L-shaped configuration with a curved back. Of the housing 1. The housing is made from structural plastic material, It could also be made from any of the other suitable structural materials, for example metals. U. The front of the housing terminates in a top that includes an air inlet 2 and an air outlet 4. And a bottom having an extension generally indicated at. Blower 5 is installed in extension 3 Have been. The extension 3 provides a convenient location for the blower 5 and additionally is stable Bring design. Filtration means in the form of a generally flat filter cartridge 6 Is mounted in the housing adjacent to the inlet 2 and is substantially flush with the inlet 2. It extends from the top of the jing to the bottom of the housing. The cross-sectional area of the cartridge is upstream And the filter cartridge to be substantially equal to the sum of the areas of the downstream passages. 6 are seen to extend across both the upstream and downstream air flow paths. Cart Within the die 6, at least one support having a photocatalyst fixed thereon is provided. A filter 7 is provided. The circulating air is indicated by arrows 9, 10, 11, and 12. After entering the inlet 2, it passes through the upper compartment of the cartridge 6 and then to the outlet 4 The compartment 8 has a filter cartridge so as to pass through the lower compartment on the way to 6 is divided into an upper filter section and a lower filter section. In this specific example Air is thus twice exposed to the filter. The filter 7 shown in FIG. A preferred structure is that the filter 7 is a pleated arrangement including a plurality of planes, Each is arranged at an angle to the main direction of the air flow. About filters This will be described in more detail below.   The ultraviolet lamp 13 acts as a light source and is provided on one side of the filter cartridge 6. Inside the side wall of the housing 1 and the filter cartridge 6 and the housing Attached between the back. UV lamps use titanium dioxide as a photocatalyst It is a preferred light source. The lamp shown is a conventional cylindrical UV lamp and Extending from one side wall of the ring to the other side wall. The lamp 13 makes efficient use of the photocatalyst. The position of the lamp 13 is not important as long as it can be realized. The lamp is easy A switch mounted on top of housing 1 for operation Switch 14 and a ballast 15 mounted at the bottom of the housing for stability. More work.   The back of the housing 1 pivots about a pivot 17 at the top of the housing, and Includes shroud 16 that can be opened upwards for easy access to the inside of the housing . Lock 18 and fastener 19 clamp the pivoting shroud 16 in the closed position. Shroud 1 6 and the polished aluminum reflective surface 20 on the back of the housing 1 The escaping light from the pump 13 is redirected to the filter 7 to maximize its efficiency. Polishing Aluminum is a preferred material for reflecting ultraviolet light.   FIG. 2 shows a front view of the device of FIG. The housing 1 has an inlet 2 (not shown). Across the entrance protection grate 30 and the exit 4 (not shown) An outlet protection grid 31 is provided.   FIG. 3 is another side view of the device shown in FIGS. 1 and 2 with the pivoting shroud 16 open. 1. Same as FIG. 1 except for the location.   In operation, the blower 5 draws outside air through the inlet 2 and the top of the filter 7 Pull in. The photocatalyst on the filter 7 is activated by the ultraviolet lamp 13 and Decomposes and disintegrates pollutants in air that come into contact with the medium. Air is behind filter 7 It continues to be drawn into the housing 1 through the perimeter and lower section of the surface, Further decomposition and destruction of the contaminants takes place in the lower compartment of the reactor. Then anti Reaction products and unreacted gas and air are discharged from the outlet 4 through the extension 3. You.   4, 5 and 6 show the filter cartridge 6 of FIG. 1 in more detail. . The cartridge 6 comprises two removable parts 40 containing a filter 7 and The portion 41 has an outer frame. Outer frame allows easy handling and protection of filter 7 To In the embodiment shown, the filter 7 has a pleated or corrugated shape. Having. The compartment 8 separates an upper (inlet) section and a lower (outlet) section of the filter. To prevent air from bypassing the filter. The fine edges 42 and 43 are It extends across the front and back and holds the filter generously in the frame.   7, 8 and 9 show three types of decomposition of a filter suitable for use in the present invention. FIG. FIG. 7 is a diagram of the filter 7 shown in FIGS. The support 71 , Blown polypropylene filled with titanium dioxide photocatalyst powder fixed electrostatically It is a double layer of fine fibers. Back layers 72 and 73 are pleated or corrugated This is a stretched metal mesh. To complete the filter 7 (shown in FIG. 1) The support layer 71 is pressed between the stretched metal mesh 72 layers 73 and A force is applied to the flexible fiber support layer 71 to form the same layer as the stretched metal mesh layers 72 and 73. Incorporate a sticky shape.   8, the support 81 is filled with the same titanium dioxide as that shown in FIG. A single layer of filled polypropylene fibers. Only one back layer 82 is used Therefore, apply a pressure-sensitive adhesive coating to either the back layer 82 or the support layer 81. By doing so, the support 81 is fixed to the back surface layer 82.   FIG. 9 shows a single support 91 between two back layers 92 and 93. Similar to FIG. 7 except that it is a layer (shown in FIG. 8). Further differences are added Is present. Fill additional support layer with titanium dioxide photocatalyst Filled polypropylene fibers, and a porous web of polyester fibers It may be a porous layer containing a conventional adsorbent, such as an activated carbon layer immobilized on a bed.   The device according to the invention improves the LP 1500 Bionarie air purifier It was built by doing. UV lamp is Southern Ultra Violet Can 15-watt, 0.348-meter (12-inch) RPR-3 from Panny 000 lamps (as used in the Rayonet photochemical reactor). The blower had two speeds. At high speed or high flow rate setting, A flow rate of Torr / min was provided. Low speed setting results in a flow rate of 604 l / min did. In the equipment used, these settings are 0.9144 m / s (180 fps). (Heat / min) (high flow) and 0.508 m / s (100 ft / min) (low flow) ).   Thus, the improved, used in the example and shown schematically in FIGS. 1, 2 and 3 The Bio Nile LP1500 air purifier weighs 0.275 m (8.75 inches). Height, 0.225 m (10.625 inches) depth, and 0.31 m (12.25 inches) Inches). These dimensions should be suitable for desktop or desktop applications. Resulting in a compact device with "printing".   The filter cartridge used was 0.2921 m (11.5 inches) wide and high It was 0.197 m (7.75 inches). The compartment is 0 from the bottom of the cartridge. . At 086m (3.38 inches) Was. The cartridge is 0.0381 m (1.5 inches) thick and has one fold The distance from to the next fold is 0.04m (1.58 inches) along the plane of the fold there were.   Therefore, a filter with 8 pleats has 16 pleats, which is . 16 inches x 1.58 inches (4064m x 0.04m) Comparable to a plain filter. The edge of the cartridge is about 0.0127 m all around ( 0.5 inches).   Example   Examples (Examples), Comparative Examples, and References (Philips) showing the present invention are as follows. Tested.   The apparatus is 0.609m × 0.609m × 0.609m unless otherwise indicated. (2 ft x 2 ft x 2 ft) (227 liters) airtight room Was. A known amount of contaminants was introduced into the room. Initial concentration of contaminants for testing The concentration was adjusted from 1500 ppm to as high as 2000 ppm (normal use). For use, the concentration would be about 1-20 ppm). After a few minutes considering equilibrium The apparatus was operated at a time and samples were taken at regular intervals using an injector. sample , A Perkin Elmer automated system with a methanizer (Perkin Elmer) mer Autosystem) was analyzed using Gas Chromatogram-9000. Isobutane and The temperature of the flame ionization detector for testing accuracy when testing propane and propane From 350 ° C to 225 ° C. To test for hydrogen sulfide, determine the concentration Measured by an enclosed space monitor available from 3M under the name "Dynatel CSM 500" did.   The device is considered an industry standard product, Philips Clean Air System 75 (reference device). Philips equipment designed to eliminate odors And has two activated carbon filters. The device has a flow rate of 3136 l / min Having. Air is drawn in from the side of the device and exhausted from the top of the device.   The device was tested using the following compounds as contaminants. Isobutane, water sulfide Hydrogen, propane, diethyl ether, acetaldehyde, ethyl propionate, Allyl tylate and propyl butyrate. Table 1 below shows the pollutants used. It is shown in each of Table 15B. Tested filters and equipment / filter combinations The flow rates used for the measurement are shown in Tables 1 to 15B.   Unless otherwise indicated, the devices tested were 3 at a wavelength of 313 nanometers each. Had two UV bulbs. In particular, the number of light bulbs (same wavelength) And the wavelength (the same number of bulbs) was changed in Table 7.   The absence of a pollutant concentration reading in the table below means that during the period indicated in the table column Indicates that no reading was performed.    Prepare the filter Filter # 1   A web of blown polypropylene nonwoven fibers was stapled together. The web, With excess titanium dioxide powder (available from Degussa under the trade name "P25") The container until the web is saturated with powder Shaking inside. The web filled with titanium dioxide is placed in a draft chamber and Was depressurized using a manual depressurizer to remove loose powder. Fold the web, 8 folds Or a corrugated pleated wire mesh back layer (0.381 mm (0.0 15 inch (1.25 inch) diamond-shaped metal shell )). A second pleated wire mesh back layer to the other of the web Pressed against the surface. Thick paper (0.3098m (12 (Inch) x 0.2032 m (8 inches).Filter # 2   Using only one layer of polypropylene web, the web is pleated Except for having a backside layer on one side only on the filter # 1 Followed.Filter # 3   Glass fiber sheets were used instead of blown polypropylene fibers. Diacid Titanium iodide is prepared using the sol-gel method (eg used in US Pat. No. 4,892,712). And coated on glass fiber. Other operations related to filter # 1 It was similar.Filter # 4 and Filter # 5   Operations on filter # 1 except that scrim material was used as the back layer I followed the work. The scrim was coated with a pressure sensitive adhesive. Scrim folds Due to the difficulty of filtering, this type of filter was flat without folds.Filter # 6   One layer of titanium dioxide filled web coated with activated carbon adsorbent Operations on filter # 1, except that a layer of polyester fiber web was replaced Followed. The hybrid filter is made of polystyrene for both the photocatalytic layer and the activated carbon auxiliary layer. Having on a tellurium fiber support. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15   Clean air delivery rate (CADR) is a good parameter to compare contaminant removal rates. It is. ln (C_At/ C_A) Is plotted against time, where C_AtIs a predetermined time Concentration of C_AIs the initial concentration, the slope of the graph is the decay constant k become. Natural damping constant k_nThe results obtained without photocatalysts or other deactivators This is the gradient of the same graph. And CADR is                       CADR = (k−k_n) V Is calculated. Where V is the volume of the test chamber.   Tables A to E can be created using the above embodiment. Measure the damping constant k The calculated table is described below as a "base table", and reference examples are shown as "example codes". .   For carbon filters, CAD decreases as flow decreases (less effective). Rate). For the photocatalytic device of the present invention, the flow rate is reduced In general, CADR increases.   The result is that the device of the present invention is more effective than the activated carbon filter of the device of Philips. Especially low molecular weight gases such as isobutane, propane, acetaldehyde and hydrogen sulfide. Shows superior performance with regard to body removal.

────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Divigarpitiya, Rungis             United States, Minnesota 55133-3427,             St. Paul, Post Office Bock             Su 33427 (72) Inventor Livingstone, David E.             United States, Minnesota 55133-3427,             St. Paul, Post Office Bock             Su 33427

Claims (1)

[Claims]   1. A device for purifying air,       A housing having an air inlet and an air outlet;       Air flows from outside the housing through the inlet and along the air flow path in the housing. And a circulating hand mounted in the housing for circulating out of the outlet Steps and       Flat filtration means intersected with the circulating air flow path. Filtration means including a photocatalyst fixed to the porous support,       It is housed in a housing for directing light to the filtering means to activate the photocatalyst. And an attached light source.   2. Air flow path, upstream where air flows in one direction, and air flows in the opposite direction Having a downstream portion adjacent to the upstream portion, wherein a flat filtration means intersects the upstream portion and the downstream portion. 2. The device of claim 1, wherein the device is disposed within the housing so as to extend.   3. The apparatus of claim 1, wherein the air flow path is straight.   4. The sum of the cross-sectional areas of the upstream section and the downstream section of the air flow path is substantially equal to the cross-sectional area of the filtering means. Apparatus according to claim 2, which is equal.   5. The photocatalyst is electrostatically fixed to the support, according to any one of claims 1 to 4, The described device.   6. The photocatalyst is powdered titanium dioxide, and the light source has peak intensity in the ultraviolet B area. UV light source having a The propylene electret fiber according to any one of claims 1 to 4, apparatus.   7. The support has an expanded metal mesh structural porous back surface and the support has a fold The device according to any one of claims 1 to 4, wherein the device has an attached structure.   8. The filter means further comprises a second fibrous porous support containing an adsorbent. The apparatus according to any one of claims 4 to 4.   9. 9. The device according to claim 8, wherein the adsorbent is activated carbon.