JP2007165255A - Fluorescent light having air cleaning function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent light capable of exerting an air cleaning function by a photocatalyst with a fluorescent lamp used for general illumination, and inexpensive without causing a noise problem by eliminating a fan and the like. <P>SOLUTION: A photocatalytic filter 5 made of a ceramic and comprising a three-dimensional mesh structure of a cell number of 5-20 cpi with a photocatalyst supported thereto is attached to a reflecting plate 4 on the back face of the fluorescent lamp 3. Thereby, air efficiently permeates into the structure of the photocatalytic filter in cooperation with heat convection of the air generated around the fluorescent lamp 3 by heat generation in light emission of the fluorescent lamp 3, and an adequate air cleaning function by photocatalyst reaction can be provided even if no fan is arranged. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluorescent lamp having an air cleaning function.

  As a device for removing malodor, exhaust gas, and harmful gas in a living space or work space, an air cleaning device using a photocatalyst is known. In recent years, this device has attracted attention as a relief for sick house syndrome.

  This air purifier has a problem of securing the installation location, particularly in ordinary homes and schools, because the indoor space is narrowed by the installation. Further, in order to exert a sufficient effect, the structure becomes complicated by adding a fan or the like, resulting in a high price, which is not preferable in terms of economy.

On the other hand, a fluorescent lamp is a necessity as a lighting fixture for indoor spaces. If this fluorescent lamp has an air cleaning function, the indoor space will not be narrowed. Therefore, a fluorescent lamp having an air cleaning function using a photocatalyst has been proposed. For example, a fluorescent lamp is directly coated with a photocatalyst such as titanium oxide (Patent Document 1), and an activated carbon with a photocatalyst film is provided on the back of the fluorescent lamp (Patent Document 2).
Japanese Utility Model Publication No. 61-151739 JP 2002-140927 A

  The fluorescent lamps in each of the above-mentioned patent documents provided with a photocatalyst are particularly intended for deodorization among the air cleaning functions, and are provided with a fan to supplement the photocatalytic function. The fan forcibly distributes the air around the fluorescent lamp, improving the deodorizing function.

  However, the installation of the fan complicates the device as described above and increases the cost. In addition, when an inexpensive fan is attached, the noise becomes high, which is not preferable particularly in the use of ordinary households, schools and offices.

  An object of the present invention is to provide a fluorescent lamp that exhibits an air cleaning function by a photocatalyst with a fluorescent lamp used for general illumination and that is economical and free from noise problems by not requiring a fan or the like.

  Fluorescent lamps used for general illumination have far less ultraviolet light with a wavelength of 380 nm or less, and when this is used as a light source, air purification by a photocatalyst is possible compared to using ultraviolet lamps or sunlight as a light source. The speed is slow. For this reason, in each said patent document, as above-mentioned, the photocatalyst function is supplemented by the attachment of a fan.

  On the other hand, as a photocatalyst filter, a ceramic photocatalyst filter having a three-dimensional network structure supporting a photocatalyst is known. The three-dimensional network structure has a large surface area, so that the amount of photocatalyst supported is large. In addition, light is irradiated to the inside of the tissue by the three-dimensional network structure, and all the air passing through the internal structure of the filter collides with the photocatalyst carried on the column part of the network structure, so that the reaction efficiency of the photocatalyst is excellent.

  The present inventors attached a photocatalytic filter having a three-dimensional network structure to a reflector on the back of the fluorescent lamp, and limited the number of cells of the photocatalytic filter to a specific range. Knowing that coupled with the heat convection of the air, the air can efficiently pass through the structure of the photocatalytic filter, and that a sufficient air cleaning function can be obtained by photocatalytic reaction without providing a fan, leading to the present invention. It is a thing.

  That is, the fluorescent lamp of the present invention is characterized in that, in a fluorescent lamp having an air cleaning function, a ceramic photocatalyst filter having a three-dimensional network structure with 5 to 20 cpi cells carrying a photocatalyst is used. It is attached to the back reflector.

  Here, the unit cpi of the number of cells is the number of cells (holes) per inch in a plane. The photocatalytic filter having a three-dimensional network structure used in the present invention has a large cell size when the number of cells is less than 5 cpi, thereby promoting air circulation due to thermal convection. However, the number of columns constituting the three-dimensional network structure is small. This is because the number of collisions between the air and the photocatalyst decreases, and the effect of air purification is reduced. In addition, the number of pillar portions constituting the three-dimensional network structure is reduced, and sufficient strength as a photocatalytic filter cannot be ensured.

  Conversely, when the number of cells exceeds 20 cpi, the number of pillars increases, and the contact area between air and the photocatalyst increases. However, because the size of the cell is reduced and the amount of air flow associated with thermal convection is reduced, the air purification effect is also inferior in this case.

  The above air cleaning effect is unique to the present invention obtained by using a photocatalytic filter having a three-dimensional network structure, limiting the number of cells, and attaching the photocatalytic filter to a reflector.

  For example, a conventional fluorescent lamp directly coated with a photocatalyst or an activated carbon coated with a photocatalytic film provided on the back side of the fluorescent lamp, even if heat convection of the air around the fluorescent lamp occurs, These contacts are on the surface of the photocatalyst carrier. Actively use the thermal convection of the air around the fluorescent lamp to allow the air to pass inside the photocatalyst carrier with a three-dimensional network structure, thereby significantly improving the photocatalytic reaction efficiency and providing an auxiliary device such as a fan. The effect of the present invention that achieves sufficient air purification cannot be obtained.

  Further, according to the present invention, since the fluorescent lamp itself as a lighting fixture has an air cleaning function, the room is not narrowed even by the installation. Moreover, it is economical because it does not require a fan, and there is no noise problem. Therefore, it is particularly preferable for use in general households, schools, offices and the like.

  In the fluorescent lamp to which the photocatalytic filter is attached, it is preferable that the fluorescent lamp has a white or daylight emission color and emits near ultraviolet rays having a wavelength of 380 nm or less in order to obtain a function as general illumination. Examples of the shape of the fluorescent lamp include a circle tube, a U-shaped tube, and a bulb type in addition to a straight tube. In the present invention, a straight tube in which a photocatalytic filter can be easily installed on the back surface of the fluorescent lamp is preferable among fluorescent lamps.

  The production of the photocatalytic filter having a three-dimensional network structure is as follows, for example. First, an organic or inorganic binder is added to an inorganic fine powder of alumina, silica or silica-alumina, and about 30 to 35% by mass of water is added as an outer shell to form a slurry. The slurry is infiltrated and adhered to a porous body having an organic three-dimensional network structure whose size and shape correspond to the photocatalytic filter used in the present invention. The material of the organic porous material is, for example, polyurethane foam.

  Next, the organic porous body from which the excess slurry has been removed is dried and fired. By this firing, the organic porous body disappears, and a ceramic three-dimensional network structure can be obtained. The firing temperature is, for example, 1000 to 1300 ° C. according to the ceramic material.

  The ceramic three-dimensional network cell is formed by adhering the slurry to the pillar portion of the organic porous structure, so that a three-dimensional network structure with the number of cells limited in the present invention is obtained. An organic porous material having a structure corresponding to the number of cells is used. FIG. 5 is a partially enlarged view of an example of a ceramic three-dimensional network structure.

  Photocatalysts supported on this ceramic three-dimensional network structure include titanium oxide, tin oxide, zinc oxide, strontium titanate, tungsten oxide, zirconium oxide, niobium oxide, iron oxide, copper oxide, iron titanate, oxidation Examples include nickel, bismuth oxide and silicon oxide. Among these, titanium oxide having excellent visible light response is particularly preferable.

  The photocatalyst such as titanium oxide is dispersed with a solvent such as water, the three-dimensional network structure is immersed, and the photocatalyst is attached to the surface of the column constituting the network of the three-dimensional network structure. Next, the photocatalyst powder is sintered and fixed by heating at a temperature of 400 to 600 ° C., for example. Titanium oxide includes anatase, rutile and brookite crystal forms. The heating temperature of 400 to 600 ° C. is for ensuring an anatase type exhibiting a photocatalytic function effective as a photocatalytic filter.

  The number of cells of the three-dimensional network structure is 5 to 20 cpi. If it is less than 5 cpi, the contact area with a photocatalyst will decrease and it will be inferior to the effect of air purification. If it exceeds 20 cpi, the permeation of air by thermal convection becomes insufficient, and in this case, the effect of air purification is also inferior. A more preferable cell number is 5 to 15 cpi.

  FIG. 1 is a perspective view of an essential part showing an application example of the present invention in a fluorescent lamp provided with a straight fluorescent lamp, and FIG. 2 is a side view of a partially crushed cross section. A lamp socket 2 is provided at both lower ends of the fluorescent lamp body 1, and a fluorescent lamp 3 is mounted on the lamp socket 2. The reflector 4 also serves as a shade for the fluorescent lamp 3. The above structure is a general fluorescent lamp.

  In the present invention, the photocatalytic filter 5 having the above-described configuration limited in the present invention is attached to the reflector 4 on the back of the fluorescent lamp 3. The shape of the photocatalytic filter 5 is, for example, a flat plate shape as shown in the figure, and is attached over the length direction of the fluorescent lamp. In the illustrated example, two photocatalytic filters 5 are used, but the total length may be one, or may be further divided into, for example, 3 to 5.

  The attachment structure of the photocatalytic filter 5 to the reflector 4 is not particularly limited. In the example shown in the figure, the photocatalytic filter 5 is suspended by a locking metal fitting 6 having a claw portion whose base end is fixed to the reflecting plate 4 and bent inward. Means such as providing a through hole in the photocatalyst filter 5 and attaching it to the reflection plate 4 with a bolt or the like, or attaching to the reflection plate 4 using a magnet or a hook-and-loop fastener may be used.

  The illustrated fluorescent lamp is of a type that is directly attached to the ceiling of the room. Although not shown in the figure, it may be suspended from the ceiling by a hanging tool. Moreover, the fluorescent lamp provided with two or more fluorescent lamps may be sufficient. In a fluorescent lamp provided with a plurality of fluorescent lamps, the photocatalytic filter may be installed, for example, by extending the lateral width of the photocatalytic filter or between the fluorescent lamps 3 and 3 as shown in FIG.

  Further, some fluorescent lamps use a circle tube as a fluorescent lamp. In this case, although not shown in the drawing, the photocatalytic filter 5 may be formed in a disk shape or a donut shape, for example, in accordance with the shape of the circle tube.

  4A to 4C are cross-sectional views perpendicular to the length direction of the fluorescent lamp, and schematically show thermal convection of air at the same time. FIG. 4A shows the photocatalyst filter 5 attached so that the upper surface of the photocatalyst filter 5 is in contact with the reflector 4, and heat convection of the air is generated by the heat generation of the fluorescent lamp 3, and the air near the fluorescent lamp 3 Passes through the mesh of the photocatalytic filter 5 and air purification is promoted.

  FIG. 4B shows an example in which the back surface of the photocatalytic filter 5 is attached to the reflecting plate 4 while being separated from the reflecting plate 4 by, for example, about 5 to 15 mm. In the example of FIG. 4 (a), air enters from the lower surface and permeates to the side surface, whereas in the example of FIG. 4 (b), air permeates from the lower surface to the upper surface, so that air permeates the photocatalytic filter 5. The speed is increased, and the room air cleaning process is accelerated accordingly.

  When at least the surface of the photocatalytic filter facing the fluorescent lamp is a concave curved surface, the lower surface of the end portion in the width direction of the photocatalytic filter has a short distance from the fluorescent lamp, and the photocatalytic reaction due to irradiation of the fluorescent lamp is promoted. FIG. 4C shows an example in which the entire surface of the photocatalytic filter 5 has the same thickness and the surface facing the fluorescent lamp 3 is a concave curved surface. However, the same effect can be obtained by using a photocatalytic filter in which only the surface facing the fluorescent lamp is a concave curved surface and the back surface is a horizontal surface.

  Examples of the present invention and comparative examples thereof are shown below. In addition, the results of testing these air purification functions are shown.

  The manufacturing method of the photocatalyst filter used for the Example is as follows. That is, a porous urethane foam suitable for forming a three-dimensional network structure is immersed in a silica-alumina slurry, and the silica-alumina slurry is sufficiently infiltrated and then dried. After removing excessive dry ceramic deposits on the surface of the urethane foam, firing was performed at 1200 ° C., and a ceramic sintered body having a three-dimensional network structure was obtained by disappearance of the urethane foam.

  Next, the ceramic sintered body is dipped in an aqueous titanium oxide solution, coated with titanium oxide on the surface of the three-dimensional network, dried, and heated at 600 ° C. or lower to support a photocatalyst made of anatase-type titanium oxide. A photocatalytic filter was obtained. The number of cells in the three-dimensional network structure was adjusted according to the number of cells of the porous urethane foam. In order to test the relationship between the number of cells and air purification, four types of photocatalytic filters having different numbers of cells were manufactured and prepared.

  As the fluorescent lamp, FB211P (straight tube 20W type, one lamp) manufactured by Hitachi Lighting Co., Ltd. was used. The photocatalyst filter was fixed to the reflecting plate with a locking bracket on the reflecting plate on the back of the fluorescent lamp. As for the shape and dimensions of the photocatalytic filter, two plate-shaped (200 × 60 × 15 mm) filters were connected in series in the length direction of the fluorescent lamp. In order to improve air circulation between the photocatalyst filter and the reflector, a spacer was placed and placed on it. Furthermore, in order to improve the light efficiency of the fluorescent lamp, an aluminum thin film was attached as a reflective thin film on the surface of the reflecting plate to reflect the light passing through the photocatalytic filter.

A fluorescent lamp equipped with a photocatalyst filter is attached to the ceiling in a 1 m ³ sealed chamber, and the acetaldehyde concentration is adjusted to 50 ppm with an acetaldehyde reagent in the sealed chamber. Measured and investigated the effect of air purification.

  The graph of FIG. 6 shows the relationship between the number of cells of the photocatalytic filter and air purification in the above test. In the fluorescent lamp using the photocatalytic filter having the number of cells within the range of the present invention, it can be confirmed that the effect of air cleaning is remarkable.

  Fig. 7 shows a domestic air cleaner manufactured by Company A (size: width 40 x depth 20 x height 60 cm) with a photocatalytic filter equipped with a fan and a commercially available deodorizer for large refrigerators (Esthetic Chemical). The result of carrying out a deodorization comparison test with a product name "antibacterial deodorized charcoal" manufactured by Co., Ltd. is shown. As shown in FIG. 7, it can be confirmed that the product of the present invention has a function substantially the same as that of a domestic air purifier with a simple structure.

It is a principal part perspective view which shows the example of application of this invention. It is a side view of the partial crushing cross section of the application example shown in FIG. It is sectional drawing which shows the other example of arrangement | positioning of a photocatalytic filter. It is sectional drawing which shows typically the thermal convection of air in the fluorescent lamp of this invention. It is a partially enlarged view of an example of a ceramic three-dimensional network structure. It is a graph which shows the result of having tested the relationship between the number of cells of a photocatalyst filter, and air purification. It is a graph which shows the deodorizing comparison test result of the fluorescent lamp of this invention, a household air cleaner, and the deodorizer for large sized refrigerators.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluorescent lamp body 2 Lamp socket 3 Fluorescent lamp 4 Reflector plate 5 Photocatalyst filter 6 Locking bracket

Claims (3)

  A fluorescent lamp having an air cleaning function, in which a photocatalytic filter made of ceramic having a three-dimensional network structure of 5 to 20 cpi cells carrying a photocatalyst is attached to a reflector on the back of the fluorescent lamp.   2. The fluorescent lamp having an air cleaning function according to claim 1, wherein a space is provided between the ceramic photocatalytic filter and the reflecting plate.   3. The fluorescent lamp having an air cleaning function according to claim 1, wherein at least a surface of the ceramic photocatalytic filter facing the fluorescent lamp is a concave curved surface.

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