Gas Purification Equipment

Abstract

To provide a gas purification device capable of optimizing deodorization performance and sterilization and inactivation performances.SOLUTION: A gas purification device according to an embodiment includes: a housing having a space therein through which a gas to be treated flows; a photocatalyst body provided inside the housing and having a photocatalyst; and a light source provided inside the housing and facing the photocatalyst. The light source includes a first light emitting element, a second light emitting element, and a substrate. The first light emitting element and the second light emitting element are provided on the surface of the substrate facing the photocatalyst. The first light emitting element irradiates the photocatalyst with first ultraviolet light having a first peak wavelength. The second light emitting element irradiates the gas flowing through the inside of the housing with second ultraviolet light having a second peak wavelength shorter than the first peak wavelength. A distance between the photocatalyst and the surface of the substrate facing the photocatalyst is 200 mm or more and 700 mm or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a gas purification device. [Background technology]

[0002] Reflecting growing health consciousness, there is an increasing demand for gas purification (e.g., air purification) in so-called closed spaces such as the interiors of trains and automobiles, refrigerators, living spaces, etc. For example, there is an increasing demand for deodorizing the atmosphere (e.g., removing VOCs (Volatile Organic Compounds) such as ammonia, ethylene, and acetaldehyde contained in the atmosphere) and sterilizing or inactivating bacteria and viruses contained in the atmosphere.

[0003] Therefore, a gas purification device has been proposed that includes a light source having a plurality of light-emitting elements and a photocatalyst body having a photocatalyst. Also proposed is a gas purification device that includes a light-emitting element for exhibiting a photocatalytic action and a light-emitting element for sterilizing or inactivating bacteria and viruses.

[0004] Here, the shorter the peak wavelength of ultraviolet light, the stronger the ability to sterilize or inactivate. Therefore, the light-emitting element for sterilization or inactivation emits ultraviolet light with a shorter peak wavelength than the light-emitting element for exerting photocatalytic action.

[0005] However, in general, the radiation intensity of a light-emitting element that irradiates ultraviolet light with a short peak wavelength is lower than the radiation intensity of a light-emitting element that irradiates ultraviolet light with a long peak wavelength. Therefore, simply providing a light-emitting element that emits ultraviolet light with a short peak wavelength and a light-emitting element that emits ultraviolet light with a long peak wavelength inside the housing may result in insufficient deodorization of gas through photocatalytic action, or insufficient sterilization or inactivation through ultraviolet light with a short peak wavelength.

[0006] In this case, by increasing the number of light-emitting elements that irradiate ultraviolet light with a long peak wavelength and the number of light-emitting elements that irradiate ultraviolet light with a short peak wavelength, it is possible to improve the deodorizing performance and the sterilization and inactivation performance. However, increasing the number of light-emitting elements leads to an increase in the price and size of the gas purification device. Therefore, there has been a demand for the development of a gas purification device that can optimize deodorizing performance, as well as sterilization and inactivation performance. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7025731 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a gas purification device that can optimize deodorizing performance and sterilization and inactivation performance. [Means for solving the problem]

[0009] The gas purification device according to the embodiment includes a housing having a space therein through which a gas to be treated flows; a photocatalyst body having a photocatalyst provided inside the housing; and a light source provided inside the housing and facing the photocatalyst body. a bracket provided on an inner wall of the housing to which the light source is attached; The light source includes a first light-emitting element, a second light-emitting element, and a substrate. The surface of the substrate opposite to the surface facing the photocatalyst is provided on the bracket. The first light-emitting element and the second light-emitting element are provided on the surface of the substrate facing the photocatalyst. The first light-emitting element irradiates the photocatalyst with first ultraviolet light having a first peak wavelength. The second light-emitting element irradiates the gas flowing inside the housing with second ultraviolet light having a second peak wavelength shorter than the first peak wavelength. The distance between the photocatalyst and the surface of the substrate facing the photocatalyst is 200 mm or more and 700 mm or less. The position of the bracket can be changed in the direction of the central axis of the housing. [Effects of the Invention]

[0010] According to an embodiment of the present invention, it is possible to provide a gas purification device that can optimize deodorizing performance and sterilization and inactivation performance. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic perspective view illustrating a gas purification device according to an embodiment of the present invention. [Figure 2] 2 is a schematic cross-sectional view of the gas purification device in FIG. 1 taken along line AA. [Figure 3] FIG. 2 is a schematic perspective view of a light source. [Figure 4] 10 is a graph illustrating the relationship between the irradiation distance L (mm) and the deodorizing performance and the disinfecting performance (sterilization and inactivation performance). DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be illustrated with reference to the drawings. In the drawings, like components are designated by like reference numerals and detailed descriptions thereof will be omitted where appropriate.

[0013] The gas purification device 1 according to this embodiment purifies gas G in the atmosphere in which the gas purification device 1 is installed. The gas G is mainly composed of air, for example, and contains substances to be purified. The substances to be purified may be substances that can be purified by at least one of photocatalysis and ultraviolet light. The substances to be purified include, for example, chemical substances, bacteria, viruses, etc. The chemical substances are, for example, ammonia, ethylene, and VOCs such as acetaldehyde.

[0014] FIG. 1 is a schematic perspective view illustrating a gas purification device 1 according to the present embodiment. FIG. 2 is a schematic cross-sectional view of the gas purification device 1 in FIG. 1 taken along line AA. As shown in FIGS. 1 and 2, the gas purification device 1 includes, for example, a housing 2, a filter 3, a light blocking section 4, a blower 5, a photocatalyst 6, and a light source 7.

[0015] The housing 2 is box-shaped. The housing 2 has a space inside through which the gas G to be treated flows. When viewed from a direction along the central axis of the housing 2, the outline of the housing 2 can be, for example, a polygon. The outline of the housing 2 illustrated in FIGS. 1 and 2 is a rectangle. If the outline of the housing 2 is a rectangle, it becomes easier to attach and detach the filter 3, the light blocking portion 4, and the photocatalyst 6, and the space efficiency of the gas purification device 1 can be improved.

[0016] The housing 2 has a shape that extends in one direction. For example, the shape of the housing 2 is a rectangular parallelepiped. At least one hole 2a can be provided at one end of the housing 2 in the direction of the central axis of the housing 2. The hole 2a serves as an inlet for the gas G to be treated. When one hole 2a is provided, the hole 2a can be provided at the position of the central axis of the housing 2, as exemplified in Figures 1 and 2. When multiple holes 2a are provided, it is preferable to provide the multiple holes 2a at positions that are point-symmetric with respect to the position of the central axis of the housing 2.

[0017] At least one hole 2b can be provided at the other end of the housing 2. The hole 2b serves as an outlet for the treated gas G. For example, as illustrated in Figures 1 and 2, a plurality of holes 2a can be provided at positions that are point-symmetric with respect to the central axis of the housing 2. If the holes 2a and 2b are provided, the internal space of the housing 2 becomes a flow path for the gas G that flows from one end of the housing 2 to the other end.

[0018] Increasing the size or number of holes 2a and 2b can increase the flow rate or flow rate of gas G, and therefore the amount of gas G that can be processed. However, increasing the size or number of holes 2a and 2b can make it easier for ultraviolet light irradiated from light source 7 to leak out of housing 2 through holes 2a and 2b. Therefore, the size, number, and arrangement of holes 2a and 2b can be changed as appropriate depending on the application of gas purification device 1, the installation environment of gas purification device 1, and the like.

[0019] In addition, a hole 2c is provided in the side of the housing 2, and the filter 3, the light blocking portion 4, the photocatalyst 6, and the light source 7 can be attached and detached through the hole 2c. A lid 2d can be detachably provided on the hole 2c. In addition, a connector can be provided on the side of the housing 2 to electrically connect a lighting circuit or a power source provided outside the housing 2 to the light source 7 provided inside the housing 2.

[0020] The materials of the housing 2 and the lid 2d are not particularly limited as long as they are resistant to the ultraviolet rays irradiated from the light source 7 and the chemical substances contained in the gas G and do not transmit the ultraviolet rays irradiated from the light source 7. The materials of the housing 2 and the lid 2d can be, for example, metal or resin. The metal may be, for example, iron, stainless steel, aluminum alloy, etc. When the material of the housing 2 and the lid 2d is metal, the housing 2 and the lid 2d may be formed by, for example, sheet metal processing. The resin may be, for example, a thermoplastic resin such as ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin), polypropylene resin, acrylic resin (polymethyl methacrylate resin), etc. When the housing 2 and the lid 2d are made of resin, the housing 2 and the lid 2d may be formed by, for example, injection molding.

[0021] The filter 3 can be provided inside the housing 2. The filter 3 is provided near the hole 2a of the housing 2. The filter 3 faces the hole 2a. The filter 3 can be detachably attached to a bracket provided on the inner wall of the housing 2, for example. The filter 3 can also be provided outside the housing 2. In this case, the filter 3 can be provided at the end of the housing 2 so as to cover the hole 2a.

[0022] The filter 3 prevents dust and other particles outside the housing 2 from being sucked into the internal space of the housing 2. The filter 3 captures dust particles of a size that can be seen with the naked eye, for example. The filter 3 can be, for example, a stainless steel plain woven wire mesh (wire diameter φ0.1 mm, 100 mesh). The filter 3 may also be, for example, a stainless steel tatami woven wire mesh or twill woven wire mesh.

[0023] The light-shielding unit 4 can be provided inside the housing 2. The light-shielding unit 4 blocks ultraviolet light irradiated from the light source 7 from leaking outside the housing 2, while allowing the gas G to pass through. The light-shielding unit 4 has, for example, a frame body and multiple light-shielding plates. The frame body is frame-shaped and is provided inside the housing 2 (the flow path of the gas G). The multiple light-shielding plates are provided inside the frame body. The multiple light-shielding plates are inclined at the same angle and are spaced apart from each other. The multiple light-shielding plates can have, for example, a plate shape, a dogleg shape, a curved shape, or the like. In this case, the spaces between the multiple light-shielding plates form the flow path of the gas G. The light-shielding unit 4 may be plate-shaped and have holes penetrating in the thickness direction.

[0024] The light shielding part 4 can be detachably attached to, for example, a bracket provided on the inner wall of the housing 2. The light shielding part 4 can be provided between the end of the housing 2 where the hole 2b is provided and the light source 7. The light shielding part 4 prevents ultraviolet rays emitted from the light source 7 from leaking out of the housing 2 through the hole 2b of the housing 2. The light shielding part 4 is formed from a material that does not transmit ultraviolet rays. The material of the light shielding part 4 can be the same as the material of the housing 2, for example.

[0025] The blower 5 can be provided inside the housing 2. The blower 5 can be provided near the end of the housing 2 on the outflow side of the gas G. The blower 5 can be provided between the end of the housing 2 where the hole 2b is provided and the light-shielding part 4. The blower 5 exhausts the gas G inside the housing 2 to the outside of the housing 2 via the light-shielding part 4. Therefore, a flow of gas G is formed inside the housing 2 from the filter 3 side toward the blower 5 side. 2 is a two-propeller fan, the number and type of blower 5 can be changed as appropriate. For example, blower 5 may be a sirocco fan.

[0026] The blower 5 can also be provided outside the housing 2. In this case, the blower 5 can be connected to the hole 2b of the housing 2 via a pipe such as a duct. Also, one blower 5 can be connected to multiple housings 2 via a pipe such as a duct.

[0027] The photocatalyst 6 can be provided inside the housing 2. The photocatalyst 6 can be detachably attached to, for example, a bracket provided on the inner wall of the housing 2. The photocatalyst 6 can be provided near the end of the housing 2 on the inflow side of the gas G. The photocatalyst 6 can be provided between the filter 3 and the light source 7.

[0028] The photocatalyst body 6 has, for example, a substrate and a photocatalyst. For example, the substrate can be a ceramic plate having a honeycomb structure and a plurality of holes with a diameter of about 3 mm. The substrate can also be a sheet formed by weaving a plurality of glass fibers. The substrate can also be a sheet formed by weaving a plurality of linear bodies containing a metal. Examples of the metal contained in the linear bodies include stainless steel, nickel, Monel, phosphor bronze, titanium, copper, copper alloy, silver, and silver alloy.

[0029] Using a ceramic substrate or a substrate made of multiple linear bodies including a metal can increase the rigidity of the substrate, which can increase the flow rate and velocity of the gas G passing through the substrate, thereby improving the processing capacity.

[0030] The photocatalyst is, for example, granular and exhibits photocatalytic activity when light having a predetermined wavelength is incident on it. The type of photocatalyst can be appropriately selected depending on the application of the gas purification device 1 and the substance contained in the gas G to be treated. For example, the photocatalyst can be an ultraviolet ray responsive photocatalyst or a visible light responsive photocatalyst. An ultraviolet ray responsive photocatalyst includes, for example, titanium oxide. A visible light responsive photocatalyst includes, for example, tungsten oxide, titanium oxide doped with nitrogen or the like, or titanium oxide ion-implanted with a different metal.

[0031] Here, if foreign matter such as organic matter adheres to the surface of the photocatalyst, it becomes difficult for light to enter the photocatalyst, making it difficult for the photocatalytic action to be exhibited. Therefore, the photocatalyst body 6 can further have an adhesion-preventing part. The adhesion-preventing part can be supported on the substrate together with the photocatalyst. The adhesion-preventing part contains, for example, a silicon compound. Examples of silicon compounds include silicon oxides (e.g., silicon dioxide), silicon nitrides, silicon oxynitrides, silicon carbides, and silicon sulfides. If an adhesion-preventing part containing a silicon compound is provided, it is possible to prevent foreign matter such as organic matter from adhering to the photocatalyst. Furthermore, if an adhesion-preventing part containing a silicon compound is provided, it is also possible to increase the bonding strength between the photocatalyst and the substrate.

[0032] The light source 7 irradiates the photocatalyst 6 with light having a predetermined wavelength. The light source 7 is provided inside the housing 2. The light source 7 faces the photocatalyst 6. The light source 7 can be provided between the photocatalyst 6 and the light-shielding part 4. In this case, the light source 7 is provided downstream of the photocatalyst 6 in the flow of the gas G.

[0033] 2, a bracket 7d to which the light source 7 (substrate 7a) is attached can be provided on the inner wall of the housing 2. The light source 7 (substrate 7a) can be detachably attached to the bracket 7d. Furthermore, the position of the bracket 7d can be changed in the direction of the central axis of the housing 2. By changing the position of the bracket 7d, the irradiation distance L (mm) can be changed. Details regarding the irradiation distance L (mm) will be described later.

[0034] At least one light source 7 can be provided. The gas purification device 1 illustrated in Fig. 1 and Fig. 2 includes two light sources 7 arranged side by side and spaced apart from each other. The light source 7 is electrically connected to a lighting circuit or a power source provided outside the housing 2, for example, via a connector or the like provided in the housing 2.

[0035] FIG. 3 is a schematic perspective view of the light source 7. As shown in FIG. As shown in FIG. 3, the light source 7 includes, for example, a substrate 7a, a light emitting element 7b (corresponding to an example of a first light emitting element), and a light emitting element 7c (corresponding to an example of a second light emitting element). The substrate 7a has a plate shape. The substrate 7a is provided in the flow path of the gas G, facing the photocatalyst 6. Therefore, if the substrate 7a is provided, there is a risk that the flow of the gas G may be obstructed. In this case, a plurality of holes penetrating the substrate 7a in the thickness direction may be provided. However, if the size of the holes is small, the pressure loss increases, obstructing the flow of the gas G. If the size of the holes is large, restrictions will be imposed on the arrangement and number of the light-emitting elements 7b, 7c, and wiring patterns.

[0036] 2, the width W1 of the substrate 7a is made smaller than the width W2 of the photocatalyst 6. In this case, if the "width W1 (mm) of the substrate 7a / width W2 (mm) of the photocatalyst 6" is smaller than 0.5, it is easy to ensure an appropriate flow rate of the gas G.

[0037] There are no particular limitations on the material or structure of the substrate 7a. For example, the substrate 7a can be made of inorganic materials (ceramics) such as aluminum oxide or aluminum nitride, or organic materials such as paper phenol or glass epoxy. The substrate 7a may also be a metal core substrate in which the surface of a metal plate is covered with an insulating material.

[0038] When the light-emitting elements 7b and 7c generate a large amount of heat, it is preferable to form the substrate 7a using a material with high thermal conductivity from the viewpoint of heat dissipation. Examples of materials with high thermal conductivity include ceramics such as aluminum oxide and aluminum nitride, and metal core substrates. The substrate 7a may have a single-layer structure or a multi-layer structure.

[0039] The light-emitting elements 7b and 7c are arranged side by side on the surface of the substrate 7a facing the photocatalyst 6. The light-emitting elements 7b and 7c are electrically connected, for example, to a wiring pattern provided on the surface of the substrate 7a. The number and arrangement of the light-emitting elements 7b and 7c can be changed as appropriate depending on the use of the gas purification device 1, the size of the photocatalyst 6, etc. For example, the number and arrangement of the light-emitting elements 7b are determined so that the ultraviolet irradiation intensity is 1 mW / cm over most of the photocatalyst 6 (60% or more in terms of area ratio). 2 For example, the number and arrangement of the light-emitting elements 7c can be determined appropriately depending on the required sterilization and inactivation capabilities, the size of the housing 2, and the like.

[0040] The light-emitting elements 7b and 7c are not particularly limited in type. The light-emitting elements 7b and 7c may be, for example, surface-mount light-emitting elements such as PLCC (Plastic Leaded Chip Carrier) types. The light-emitting elements 7b and 7c may also be, for example, light-emitting elements having leads such as bullet types. In this case, the light-emitting elements 7b and 7c have, for example, a chip-shaped light-emitting element and a sealing portion that covers the chip-shaped light-emitting element. The material of the sealing portion is, for example, silicone resin or glass. The light-emitting elements 7b and 7c may also be chip-shaped light-emitting bodies (bare chips), for example. The chip-shaped light-emitting bodies may be mounted on a wiring pattern using, for example, COB (Chip On Board). In this case, a sealing portion may be provided to cover the chip-shaped light-emitting bodies. The sealing portion may be made of, for example, silicone resin or glass. The light emitting elements 7b and 7c illustrated in FIGS. 2 and 3 are surface-mounted light emitting elements.

[0041] The light-emitting element 7b mainly irradiates the photocatalyst 6 with light. The light-emitting element 7b mainly irradiates light for exciting the photocatalyst. In this case, if the material or composition of the photocatalyst changes, the absorption wavelength range of the photocatalyst changes. Therefore, the light-emitting element 7b that irradiates light of an appropriate wavelength is selected depending on the absorption wavelength range of the photocatalyst. For example, if the photocatalyst is an ultraviolet-responsive photocatalyst such as titanium oxide, the light-emitting element 7b can be, for example, a light-emitting diode or laser diode that irradiates ultraviolet light (UV-A) with a peak wavelength of 315 nm or more and 420 nm or less (corresponding to an example of first ultraviolet light having a first peak wavelength). Furthermore, if the photocatalyst is a visible-light-responsive photocatalyst such as tungsten oxide, the light-emitting element 7b can be, for example, a light-emitting diode, laser diode, or organic light-emitting diode that irradiates visible light with a peak wavelength of 405 nm or more and 600 nm or less.

[0042] The light-emitting element 7c mainly irradiates the gas G flowing inside the housing 2 with ultraviolet light. The light-emitting element 7c mainly irradiates ultraviolet light (which corresponds to an example of second ultraviolet light having a second peak wavelength shorter than the first peak wavelength) for sterilizing or inactivating bacteria and viruses. In this case, the shorter the peak wavelength of the irradiated ultraviolet light, the easier it is to sterilize or inactivate bacteria and viruses. For example, the light-emitting element 7c can be a light-emitting diode or a laser diode that irradiates ultraviolet light (UV-C) with a peak wavelength of 270 nm or more and 300 nm or less.

[0043] If the light-emitting element 7c is provided, it is possible to sterilize or inactivate bacteria and viruses contained in the gas G flowing inside the housing 2, as well as bacteria and viruses attached to the photocatalyst 6 or the inner wall of the housing 2.

[0044] In this case, the ultraviolet light emitted from light-emitting element 7b has a lower ability to kill bacteria or inactivate bacteria than the ultraviolet light emitted from light-emitting element 7c. However, if ultraviolet light is emitted from light-emitting element 7b, the kill bacteria or inactivate bacteria produced by the ultraviolet light emitted from light-emitting element 7c can be enhanced.

[0045] Therefore, for example, when deodorizing the atmosphere and sterilizing or inactivating bacteria and viruses contained in the atmosphere, it is preferable to use a photocatalyst 6 having an ultraviolet-responsive photocatalyst and a light-emitting element 7b that irradiates ultraviolet light. In this way, the ultraviolet light irradiated from the light-emitting elements 7b and 7c can effectively sterilize or inactivate bacteria and viruses contained in the gas G flowing inside the housing 2. In addition, bacteria and viruses adhering to the inner wall of the housing 2 can also be effectively sterilized or inactivated.

[0046] Here, silicone resin has high resistance to ultraviolet rays, but if a sealing portion containing silicone resin is used for the light-emitting element 7b, some of the silicone resin contained in the sealing portion of the light-emitting element 7b may decompose when the light-emitting element 7b is irradiated with ultraviolet rays. In this case, the shorter the peak wavelength of the irradiated ultraviolet light, the more easily the silicone resin decomposes. Therefore, when ultraviolet light with a short peak wavelength irradiated from light-emitting element 7c is reflected by the inner wall of housing 2 or photocatalyst 6 and irradiated onto the sealing portion of light-emitting element 7b, the silicone resin contained in the sealing portion of light-emitting element 7b is more likely to decompose. Furthermore, heat is generated when the light emitting element 7b emits ultraviolet light, and if the silicone resin is heated by the generated heat, the silicone resin is more likely to decompose.

[0047] When the silicone resin contained in the sealing portion of light-emitting element 7b decomposes, gas containing silicone resin components is released from light-emitting element 7b. If the silicone resin components released from light-emitting element 7b adhere to the photocatalyst, it becomes difficult for ultraviolet rays to enter the photocatalyst or for gas G to be treated to come into contact with the photocatalyst. This may cause the performance of gas purification device 1 to deteriorate over time.

[0048] 1 and 2, in the gas purification device 1 according to this embodiment, the photocatalyst 6 is provided upstream of the light source 7 in the flow of the gas G flowing inside the housing 2. In this case, when gas containing a silicone resin component is released from the light emitting element 7b, the released gas is carried along with the flow of the gas G and is discharged downstream of the photocatalyst 6. Therefore, the gas containing the silicone resin component is less likely to reach the photocatalyst 6, and deterioration of the function of the gas purification device 1 over time can be suppressed.

[0049] Similarly, when the sealing portion of the light-emitting element 7c contains a silicone resin, a portion of the silicone resin contained in the sealing portion of the light-emitting element 7c may decompose when the light-emitting element 7c is irradiated with ultraviolet light. As mentioned above, the shorter the peak wavelength of the irradiated ultraviolet light, the more likely the silicone resin is to decompose. Therefore, the silicone resin contained in the sealing portion of the light-emitting element 7c decomposes more easily than the silicone resin contained in the sealing portion of the light-emitting element 7b. Furthermore, heat is generated when the light emitting element 7c irradiates ultraviolet light, and if the silicone resin is heated by the generated heat, the silicone resin becomes more likely to decompose.

[0050] When the silicone resin contained in the sealing portion of the light-emitting element 7c decomposes, gas containing silicone resin components is released from the light-emitting element 7c. If the silicone resin components released from the light-emitting element 7c adhere to the photocatalyst, it becomes difficult for ultraviolet rays to enter the photocatalyst or for the gas G to be treated to come into contact with the photocatalyst. As a result, the functionality of the gas purification device 1 may deteriorate over time.

[0051] As described above, in the gas purification device 1 according to this embodiment, the photocatalyst 6 is provided upstream of the light source 7 in the flow of the gas G flowing inside the housing 2. In this case, when gas containing a silicone resin component is released from the light emitting element 7c, the released gas is carried along with the flow of the gas G and is discharged downstream of the photocatalyst 6. This makes it difficult for the gas containing a silicone resin component to reach the photocatalyst 6, thereby preventing the function of the gas purification device 1 from deteriorating over time.

[0052] Furthermore, since the peak wavelength of the light-emitting element 7c is shorter, the amount of gas containing silicone resin components released from the light-emitting element 7c is greater than that from the light-emitting element 7b. In this case, the gas G flowing through the central region of the housing 2 has a faster flow rate and a larger flow rate than the gas G flowing near the inner wall of the housing 2. Therefore, as shown in FIG. 3, it is preferable to provide the light-emitting element 7c closer to the center of the substrate 7a than the light-emitting element 7b. For example, as shown in FIG. 3, the light-emitting element 7c can be provided closer to the center of the substrate 7a than the light-emitting element 7b. In this way, since the light-emitting element 7c is provided closer to the center of the housing 2 than the light-emitting element 7b, even if more gas is released from the light-emitting element 7c, the gas is less likely to reach the photocatalyst 6.

[0053] As mentioned above, the sealing material of the light-emitting elements 7b and 7c may be glass. In such cases, almost no gas is released from the light-emitting elements 7b and 7c. This prevents the performance of the gas purification device 1 from deteriorating over time. However, as described above, the light-emitting element 7c mainly emits ultraviolet light for sterilizing or inactivating bacteria, viruses, etc. Therefore, if the light-emitting element 7c is provided closer to the center of the housing 2 than the light-emitting element 7b, it becomes easier to irradiate a wider area inside the housing 2 with ultraviolet light having a shorter peak wavelength. Therefore, from the viewpoint of sterilization and inactivation of bacteria, viruses, etc., it is preferable that the light-emitting element 7c be provided closer to the center of the housing 2 than the light-emitting element 7b. For example, as shown in Fig. 3, the light-emitting element 7c can be provided closer to the center of the substrate 7a than the light-emitting element 7b.

[0054] Here, the shorter the peak wavelength of the irradiated ultraviolet light, the higher the sterilization and inactivation capabilities. However, in general, the radiation intensity of the light-emitting element 7c, which irradiates ultraviolet light with a short peak wavelength (e.g., UV-C), is lower than the radiation intensity of the light-emitting element 7b, which irradiates ultraviolet light with a long peak wavelength (e.g., UV-A). For example, the radiation intensity of the light-emitting element 7c may be about 1 / 20 of the radiation intensity of the light-emitting element 7b. If the radiation intensity of the light-emitting element 7c is low, the integrated light amount of the ultraviolet light with a short peak wavelength decreases, making it difficult to improve the sterilization and inactivation capabilities. In this case, increasing the number of light-emitting elements 7b and 7c can improve deodorizing performance and sterilization and inactivation performance. However, doing so will result in an increase in the price and size of the gas purification device 1. Furthermore, light-emitting elements 7c that emit short-wavelength ultraviolet light are expensive. Therefore, increasing the number of light-emitting elements 7c will further increase the manufacturing cost of the gas purification device 1.

[0055] Therefore, in the gas purification device 1 according to this embodiment, the deodorizing performance, and the sterilization and inactivation performance are optimized by adjusting the distance between the photocatalyst 6 and the light source 7, without increasing the number of light-emitting elements 7b and 7c.

[0056] FIG. 4 is a graph illustrating the relationship between the irradiation distance L (mm) and the deodorizing performance and the sterilizing performance (sterilization and inactivation performance). In this case, the shape of the housing 2 is a rectangular parallelepiped. The irradiation distance L (mm) can be the distance between the photocatalyst 6 and the ultraviolet light emission surface of the light-emitting elements 7b and 7c, but the thickness of the light-emitting elements 7b and 7c is smaller than the irradiation distance L (mm). Therefore, the irradiation distance L (mm) is set to the distance between the photocatalyst 6 and the surface of the substrate 7a facing the photocatalyst 6, as shown in FIG.

[0057] The light emitting element 7b was set to irradiate ultraviolet light with a peak wavelength of 365 nm, and the light intensity of the light emitting element 7b was set to 700 mW when the forward current was 350 mA. The light emitting element 7c was designed to emit ultraviolet light with a peak wavelength of 280 nm, and the light intensity of the light emitting element 7c was set to 40 mW when the forward current was 350 mA. The number of light sources 7 was two, as shown in FIG. The number and arrangement of the light emitting elements 7b and 7c were as shown in FIG. The flow rate of the gas G flowing inside the housing 2 is 5 m 3 / min.

[0058] If the irradiation distance L (mm) is shortened, the distance between the light-emitting element 7b and the photocatalyst 6 is shortened, and the irradiation intensity of the ultraviolet light irradiated onto the photocatalyst increases. If the irradiation intensity of the ultraviolet light irradiated onto the photocatalyst increases, the amount of chemical substances removed by the photocatalytic action increases. Therefore, as can be seen from Figure 4, the deodorizing performance improves. Increasing the irradiation distance L (mm) increases the distance between the light-emitting element 7b and the photocatalyst 6, thereby reducing the intensity of the ultraviolet light irradiated onto the photocatalyst. If the intensity of the ultraviolet light irradiated onto the photocatalyst decreases, the amount of chemical substances removed by the photocatalytic action decreases. Therefore, as can be seen from Figure 4, the deodorizing performance decreases.

[0059] On the other hand, if the irradiation distance L (mm) is shortened, the distance between the light-emitting element 7c and the photocatalyst 6 is shortened, and the time it takes for the gas G to pass between the photocatalyst 6 and the light source 7 is shortened. If the time it takes for the gas G to pass between the photocatalyst 6 and the light source 7 is shortened, the integrated light amount of ultraviolet light with a short peak wavelength decreases. Therefore, as can be seen from FIG. 4, the sterilization performance decreases. Increasing the irradiation distance L (mm) increases the distance between the light-emitting element 7c and the photocatalyst 6, and therefore the time it takes for the gas G to pass between the photocatalyst 6 and the light source 7. If the time it takes for the gas G to pass between the photocatalyst 6 and the light source 7 increases, the cumulative amount of ultraviolet light with a short peak wavelength increases. Therefore, as can be seen from FIG. 4, the sterilization performance improves.

[0060] In this case, as shown in FIG. 4, if the irradiation distance L (mm) is 200 mm or more and 700 mm or less, it becomes easy to optimize the deodorizing performance and the sterilizing and inactivating performance. Furthermore, as can be seen from Fig. 4, the ratio of deodorization to sterilization (sterilization and inactivation) can be changed by changing the irradiation distance L (mm). Therefore, for example, if the main use of the gas purifying device 1 is to deodorize the atmosphere, the irradiation distance L (mm) can be set to 200 mm or more and 450 mm or less. For example, if the main use of the gas purifying device 1 is to sterilize the atmosphere, the irradiation distance L (mm) can be set to 450 mm or more and 700 mm or less.

[0061] The illumination distance L (mm) can be easily adjusted by changing the position of the bracket 7d on which the light source 7 is mounted. For example, a plurality of screw holes can be provided on the inner wall of the housing 2 along the direction of the central axis of the housing 2, and the bracket 7d can be attached to the screw holes at desired positions. For example, a guide rail extending along the direction of the central axis of the housing 2 can be provided on the inner wall of the housing 2, and the bracket 7d can be movably attached to the guide rail.

[0062] Furthermore, a portion of the ultraviolet light emitted from the light-emitting element 7c is incident on the inner wall of the housing 2. Therefore, the reflectance of the inner wall of the housing 2 to the ultraviolet light emitted from the light-emitting element 7c can be made higher than the reflectance of the outer wall of the housing 2.

[0063] For example, a film containing a metal with high reflectivity to ultraviolet light can be provided on the inner wall of the housing 2. The film can be formed by plating, sputtering, or the like. Furthermore, for example, the inner wall of the housing 2 may be provided with a foil or plate material containing a metal that has a high reflectivity against ultraviolet rays. An example of a metal that has a high reflectivity to ultraviolet light is an aluminum alloy. Furthermore, when the housing 2 is made of a metal such as an aluminum alloy, the inner wall of the housing 2 can be made smooth. For example, the inner wall of the housing 2 can be made smooth by polishing the inner wall of the housing 2.

[0064] 3, if the light-emitting element 7c is provided closer to the center of the substrate 7a than the light-emitting element 7b, the ultraviolet light with a short peak wavelength emitted from the light-emitting element 7c is less likely to be incident on the inner wall of the housing 2. Therefore, the amount of ultraviolet light with a short peak wavelength irradiated onto the gas G can be increased, and the integrated amount of light can be increased.

[0065] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0066] 1 gas purification device, 2 housing, 3 filter, 4 light shielding portion, 6 photocatalytic body, 7 light source, 7a substrate, 7b light emitting element, 7c light emitting element, 7d bracket, G gas, L irradiation distance

Claims

1. a housing having a space therein through which a gas for processing flows; a photocatalyst body provided inside the housing and having a photocatalyst; a light source provided inside the housing and facing the photocatalyst; a bracket provided on an inner wall of the housing to which the light source is attached; Equipped with the light source includes a first light-emitting element, a second light-emitting element, and a substrate; a surface of the substrate opposite to the surface facing the photocatalyst body is provided on the bracket; The first light-emitting element and the second light-emitting element are provided on a surface of the substrate facing the photocatalyst, the first light-emitting element irradiates the photocatalyst with first ultraviolet light having a first peak wavelength; the second light-emitting element irradiates the gas flowing inside the housing with second ultraviolet light having a second peak wavelength shorter than the first peak wavelength; the distance between the photocatalyst and the surface of the substrate facing the photocatalyst is 200 mm or more and 700 mm or less; The gas purification device has an arrangement position of the bracket that can be changed in the direction of the central axis of the housing.

2. the first peak wavelength is 315 nm or more and 420 nm or less, 2. The gas purification device according to claim 1, wherein the second peak wavelength is not less than 270 nm and not more than 300 nm.

3. 3. The gas purification device according to claim 1, wherein the second light emitting element is provided closer to the center of the substrate than the first light emitting element.

4. 4. The gas purification device according to claim 1, wherein the reflectance of the inner wall of the housing to the second ultraviolet light is higher than the reflectance of the outer wall of the housing.

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