JP7315140B2 - photocatalyst unit - Google Patents

Description

The present invention relates to a photocatalyst unit that purifies fluid such as air with a photocatalyst.

Conventionally, an air purifier having an air purifying structure that decomposes viruses and the like using a photocatalyst has been proposed (see Patent Documents 1 and 2, for example). These conventional air cleaning structures using photocatalysts consist of a plate-shaped base material (filter base material) having a large number of air passage holes penetrating in the thickness direction, and forming a photocatalyst filter by supporting a photocatalyst such as titanium oxide on one surface of the front and back surfaces. It is a structure that circulates air in the gap between In the process of passing through the photocatalyst layer, harmful substances in the air are decomposed and removed by the photocatalyst excited by ultraviolet rays.

In such an air purification structure using a conventional photocatalyst unit, since the photocatalyst filter and the ultraviolet lamp are arranged facing each other in the filter thickness direction, the thickness of the unit increases, and there is a limit to making it thin and compact. In addition, since it is a structure in which air flows between the ultraviolet lamps, there is a limit to increasing the number of ultraviolet lamps that act as air resistance, and there is a certain limit to improving the irradiation amount of ultraviolet rays to the photocatalyst filter and the irradiation efficiency. For example, even if the photocatalyst is supported deep inside the air passage holes of the plate-shaped base material, it is difficult to efficiently irradiate the ultraviolet rays to the deep part.

On the other hand, a plurality of plate-like portions each carrying a photocatalyst on its front and back surfaces are arranged so that the front and back surfaces of the adjacent plate-like portions face each other with a gap therebetween, thereby forming a photocatalyst filter using the gaps as air flow paths. An air cleaning structure has been proposed in which an ultraviolet irradiation unit that irradiates is arranged, and air is taken in from the side substantially parallel to the end surface of each plate-shaped part between the ultraviolet irradiation unit and the end surface of each plate-shaped part, and an air supply path for supplying air to the flow path formed by the gap between the plate-shaped parts, or an air discharge path for discharging the air coming out of the flow path to the side substantially parallel to the end surface (see Patent Document 3).

In such an air purifying structure, the ultraviolet irradiation section is arranged at a predetermined distance from the end surface of each plate-shaped portion of the photocatalyst filter on the air inlet side or the air outlet side, and between the ultraviolet irradiation section and the end surface of each plate-shaped section, an air supply path for taking in air from the side substantially parallel to the end surface or an air discharge path for discharging air from the side substantially parallel to the end surface is formed. Since air is not supplied or discharged through the gap of the ultraviolet lamp, the ultraviolet irradiation section is free to design. It becomes easy to efficiently irradiate the ultraviolet rays by the photocatalyst of each plate-like portion and significantly improve the air cleaning action by the photocatalyst.

However, since such an air cleaning structure is a structure in which air is supplied or discharged from the side between the ultraviolet irradiation part and the photocatalyst filter in an L-shape, the air supply/discharge form (flow path) is limited, and the size of the entire unit is increased.

Utility Model Registration No. 3150894 Japanese Patent Publication No. 2011-114894 JP 2017-148484 A

Therefore, in view of the above-mentioned situation, the present invention aims to provide a fluid cleaning structure using a photocatalyst, which can efficiently irradiate a photocatalyst with ultraviolet rays to improve the fluid cleaning action of the photocatalyst, and at the same time, can be thin and miniaturized as a photocatalyst unit composed of a photocatalyst filter and a light irradiation part, and has a high degree of freedom in designing the flow path structure.

The present invention includes the following inventions.
(1) A photocatalyst filter made of a corrugated metal member in which a plurality of peaks and valleys are alternately formed, a fluid passage hole for passing a fluid is formed in one or both of the tops of the peaks and the bottoms of the valleys, and a photocatalyst is supported on the front and back surfaces; The photocatalyst unit is provided with a metal light source mounting base having a substantially U-shaped or U-shaped cross section, which has a plate-shaped base portion on which the light irradiating portion is arranged oppositely along the end surface of the photocatalyst filter on the one end side or the other end side, on which the light source for irradiating the light is mounted, and a pair of supporting pieces extending from the respective edge sides of the front side and the back side of the photocatalyst filter of the base part to the front side and the back side of the photocatalyst filter and fixed to the front side or the back side. A photocatalyst unit characterized by:

(2) The photocatalyst unit according to (1), wherein a rod-shaped lens is provided between the light source of the base portion of the light irradiation portion and the end face of the photocatalyst filter facing the light source, for condensing the light from the light source in the direction of the end face.

(3) The photocatalyst unit according to (1) or (2), wherein a plate member made of a dissimilar metal having better thermal conductivity than the metal constituting the light source mount is joined to the outer surface of the base portion of the light irradiation portion, which is opposite to the surface facing the end surface of the photocatalyst filter.

According to the above-described present invention, both surfaces of a photocatalyst filter having a corrugated shape and a sufficient surface area are irradiated with light inwardly along the direction in which the ridges or troughs extend from the light irradiating portions provided on one or both ends of the filter. By passing the fluid through the fluid passage holes in the thickness direction of the filter, harmful substances and odors in the fluid can be efficiently decomposed and removed by the photocatalyst supported on the front and back surfaces of the filter and the inner surfaces of the fluid passage holes.

In addition, the light irradiation unit is not provided at a position facing the filter surface as in the conventional art, but is provided at one or both of one end side and the other end side of the photocatalyst filter in the direction in which the peaks and valleys extend, and is configured to irradiate ultraviolet light or visible light from that position toward the inside where the peaks and valleys extend. Therefore, it is possible to flow the fluid straight in the thickness direction of the filter without being obstructed by the light irradiation unit, and the degree of freedom in designing the flow path is improved. The unit can be remarkably thin and compact.

Further, the light irradiating part is provided with a metal light source mounting base having a substantially U-shaped or U-shaped cross-section, which has a plate-like base to which a light source for irradiating light is mounted, and a pair of support pieces extending from the front and back sides of the photocatalyst filter of the base to the front and back sides of the photocatalyst filter, respectively, and fixed to the front or back surface of the photocatalyst filter. By using the filter itself as a heat sink, heat can be efficiently dissipated during the flow passing through the filter in the thickness direction, and heat can be prevented from being trapped in the vicinity of the light source while achieving thinness and compactness as described above.

Further, if a rod-shaped lens is provided between the light source of the base part in the light irradiation part and the end face of the photocatalyst filter facing it, the light from the light source is collected in the direction of the end face, so that the light can be efficiently delivered to the photocatalyst filter farther and the photocatalyst action can be made more efficient.

In addition, when a plate member made of a dissimilar metal having better thermal conductivity than the metal constituting the light source mounting base is joined to the outer surface of the light irradiation portion opposite to the surface of the base portion facing the end surface of the photocatalyst filter, the heat of the light source can be absorbed more efficiently and the heat can be efficiently transferred to the photocatalyst filter side through the support piece, so that the heat can be more reliably prevented from being trapped in the vicinity of the light source.

The perspective view which shows the photocatalyst unit which concerns on typical embodiment of this invention. AA vertical cross-sectional view of FIG. 1 as well. BB cross sectional view of FIG. 1 as well. FIG. 3 is an exploded perspective view showing a photocatalyst filter, a light irradiator, and a dust collection filter that also constitute the photocatalyst unit. The perspective view which similarly shows the principal part of a photocatalyst filter. Sectional drawing of the principal part of a photocatalyst filter similarly. Explanatory drawing which shows the modification which made the photocatalyst filter the several division|segmentation structure. FIG. 4 is an exploded perspective view showing another embodiment of the photocatalyst unit of the present invention; FIG. 6 is a longitudinal sectional view showing a photocatalyst unit of another embodiment; FIG. 4 is an explanatory diagram showing still another embodiment of the photocatalyst unit of the present invention;

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

1-3 show a fluid cleaning structure 1 comprising a photocatalyst unit 2 of the present invention. In addition to the photocatalyst unit 2, the fluid cleaning structure 1 includes a fluid supply path 70 that supplies fluid to one of the front and back surfaces of the photocatalyst filter 3 that constitutes the photocatalyst unit 2, a fluid discharge path 71 that discharges the fluid discharged from the other surface of the front and back surfaces of the photocatalyst filter 3, and dust collection filters 4A and 4B that are installed inside the fluid supply path 70 and the fluid discharge path 71 and provided to face the front and back surfaces of the photocatalyst filter 3.

According to this example, both surfaces of the photocatalyst filter of the photocatalyst unit 2 are irradiated with light inward along the direction in which the peaks 31 or the valleys 32 extend from the light irradiation unit 5, and the fluid is allowed to pass through the filter 3 in the thickness direction through the fluid supply path 70 and the fluid discharge path 71, and harmful substances and odors in the fluid can be efficiently decomposed and removed by the photocatalyst supported on the front and back surfaces of the filter and the inner surface of the fluid passage hole. In the present invention, fluids include liquids in addition to air and other gases. The dust collection filters 4A and 4B are not necessarily required and can be omitted.

As shown in FIGS. 4 to 6, the photocatalyst unit 2 is composed of a photocatalyst filter 3 made of a corrugated metal member in which a plurality of ridges 31 and troughs 32 are alternately formed, and a light irradiation part 5 provided at one or both of one end side and the other end side of the photocatalyst filter 3 in the direction in which the ridges 31 and troughs 32 extend.

As shown in FIGS. 4 to 6, the photocatalyst filter 3 has fluid passage holes 33 formed in one or both of the tops of the peaks 31 and the bottoms of the valleys 32 for passing a fluid, and photocatalysts are supported on the front and back surfaces. In this example, by pressing a metal plate, all of the tops of the plurality of peaks 31 and all of the bottoms of the plurality of valleys 32 are processed into a flat corrugated plate shape positioned on the same plane, and a photocatalyst layer is formed on the surface.

Further, the photocatalyst filter 3 of this example is formed into an uneven corrugated shape as a whole by forming the ridges 31 and the troughs 32 into an angular rectangular shape, but it may of course be formed into a corrugated shape in which the ridges and the troughs are smoothly continuous. The "peaks" and "troughs" are defined as "peaks" and "valleys", with one side of the corrugated surface of the uneven shape (wavy shape) as the upper surface and the other side as the lower surface. Various metal materials such as aluminum and stainless steel can be used as materials for the members, but the materials are not limited to these.

The fluid passage holes 33 need not be provided in all the ridges 31 or all the troughs 32, and may be formed by skipping one or more ridges 31 or troughs 32, for example. The dimensions, number, and arrangement of the fluid passage holes 33 can also be appropriately determined so as to obtain suitable shape retention according to the application, size, and the like of the device. In this example, two fluid passage holes 33, which are long through-grooves in the direction in which the ridges 31 or the troughs 32 extend, are connected to one ridge 31 or the troughs 32 at intervals, and a bridging portion 34 (the remainder between the fluid passage holes 33 in the ridges 31 or the troughs 32) is formed to maintain the overall shape retention. However, the length and spacing of the fluid passage holes 33 can be appropriately determined according to the plate thickness, other dimensions, and the degree of shape retention required.

A pair of opening edges facing each other along the longitudinal direction of the fluid passage hole 33 are provided with standing pieces 35 which are cut and raised to form the fluid passage hole 33 and stand on the convex surface side of the peak portion 31 or the valley portion 32. The photocatalyst filter 3 in which the standing pieces 35 are formed in this manner has a large surface area that contacts the gas due to the corrugated uneven surface formed by the peaks 31 and the valleys 32. At the same time, the inner surface of the fluid passage hole 33 formed in the peaks 31 or the valleys 32 and the standing pieces 35 at the opening edge also increase the contact area with the gas and light. Therefore, the catalytic reaction is efficiently carried out.

The standing pieces 35 can be efficiently formed by cutting and raising by punching at the same time as or immediately after the pressing of the concave-convex shape. The upright strips 35 provided on both sides of the opening edge are long strips extending substantially over the entire length of each opening edge, but it is of course possible to provide a plurality of upright strips at intervals. In this case, standing pieces having a long protruding length can be formed alternately (in a zigzag pattern) on both opening edges by cutting and lifting. By cutting and raising both sides from the center, the height dimension of the upright pieces provided on both sides of the opening edge becomes the same dimension, specifically, the dimension in the width direction perpendicular to the row direction of the through groove is approximately half. By forming the standing pieces 35 by cutting and raising, the base material can be used without waste, and the contact area can be maximized.

The photocatalyst layer is a layer in which photocatalyst particles such as ultraviolet-excited photocatalyst particles such as titanium oxide and visible-light-excited photocatalyst particles containing tungsten trioxide as a main component are supported on the surface of a member. In the case of forming an uneven shape composed of peaks 31 and valleys 32 by press working, if a photocatalyst layer is formed on the surface in advance, the layer may peel off or the shape accuracy may be disturbed. In order to avoid this, the above layer may be formed after processing into an uneven shape. The method for supporting the photocatalyst particles (forming the photocatalyst layer) is not particularly limited, but slurry dipping and impregnation, which is relatively inexpensive, is preferred. Other means such as immersion impregnation method, vacuum impregnation method, sol-gel method can also be used.

The light irradiation unit 5 is arranged oppositely along both end surfaces in the direction in which the peaks 31 and the valleys 32 of the photocatalyst filter 3 extend, and has a plate-like base portion 520 to which the light source 51 for irradiating light is attached, and a pair of support pieces 521 that extend from the respective edges on the front side and the back side of the photocatalyst filter 3 to the front side and the back side of the photocatalyst filter 3 and are fixed to the front side or the back side by bonding with a heat conductive adhesive or by caulking. A metal light source mounting base 52 having a substantially U-shaped or U-shaped appearance is provided. Such a light irradiation unit 5 irradiates ultraviolet light or visible light from the light source 51 toward the inside of the photocatalyst filter 3 where the peaks 31 and the valleys 32 extend. The light irradiating units 5 are provided over regions of approximately the same length along both ends of the photocatalytic filter 3 in order to irradiate the entire surface of the photocatalytic filter 3 with light substantially uniformly.

As the light source 51, an LED element that emits ultraviolet light or visible light with a wavelength suitable for the photocatalyst of the photocatalytic filter 3 is used, and a long LED substrate on which the LED elements are provided at equal intervals is provided over the entire length of the base portion 520. Instead of providing such a long LED substrate, a columnar light guide member that emits light inward from the outer peripheral surface may be provided, and light sources may be provided at both ends of the light guide member, so that the light from the light source may be taken into the light guide member and radiated from the light emitting surface (outer peripheral surface) to the inner metal filter surface. In this case, the base portion may be extended to the position of the light source, and the light source may be provided on the extended portion. The illustrated one has an extended portion, which is for preventing light from leaking to the outside. In this case, the light emitting surface of the light guide member is provided with unevenness for emitting light.

The light source mounting base 52 functions as a reflector for irradiating the light inward without leaking the light from the light source 51 to the outside, and also has a function of transmitting heat generated by the light source 51 from the base portion 520 to the photocatalyst filter 3 made of metal through the support piece 521, and dissipating the heat from the photocatalyst filter 3 itself as a heat sink during distribution. As a result, the heat generated by the light source is efficiently dissipated while achieving thinness and compactness. In particular, in this example, the support pieces 521 are attached to the top surfaces of the flat peaks 31 and the rear surfaces of the flat valleys 32 at the ends of the angular wave-shaped photocatalyst filter 3 having no fluid passage holes 33, as described above, by bonding or crimping in a state of surface contact, so that the contact area is secured, the heat conduction efficiency of the heat from the support pieces 521 to the photocatalyst filter 3 is high, and an excellent heat dissipation effect is exhibited.

In this example, between the light source 51 of the base portion of the light irradiation unit 5 and the end face of the photocatalyst filter 3 that faces the light source 51, a rod-shaped lens 50 that collects the light from the light source 51 in the direction of the end face is provided. Here, a columnar light guide member is provided as the lens 50 . Further, although not shown, a plate made of a dissimilar metal having better thermal conductivity than the metal constituting the light source mounting base 52 is joined to the outer surface of the base portion 520 opposite to the surface facing the end surface of the photocatalytic filter 3, thereby more efficiently absorbing the heat of the light source 51 and efficiently transmitting the heat to the photocatalytic filter 3 side through the supporting piece 521, thereby more reliably preventing heat buildup in the vicinity of the light source.

The light emitted from the light source 51 to the filter surface activates the photocatalyst on the surface, passes through the fluid passage hole 33 of the filter 3 to the other surface side, is reflected by the surfaces of the dust collection filters 4A and 4B, is irradiated to the entire other surface of the photocatalyst filter 3, and similarly activates the photocatalyst on the surface. In this example, the light irradiation section 5 having the light source 51 is provided on both end sides of the photocatalyst filter 3, but it may be provided only on one side, and the other side may be provided with only a reflecting member for reflecting light inward.

The photocatalyst unit 2 including the photocatalyst filter 3 and the light irradiation unit 5 described above is surrounded by the colored light shielding wall 7 that constitutes the flow path walls of the fluid supply path 70 and the fluid discharge path 71 together with the dust collection filters 4A and 4B. The light shielding wall 7 covers the end face 36 of the photocatalyst filter 3 excluding the front and back surfaces (the side where the light irradiation part 5 exists) and the end faces 40 of the dust collection filters 4A and 4B adjacent to the end face 36, and is configured so that the light from the light irradiation part 5 does not leak to the outside.

The dust collection filters 4A and 4B are of corrugated type, and are preferably HEPA (High Efficiency Particulate Air) filters made of filter media such as glass fiber or synthetic fiber, but may be other dust collection filters. The size is set to cover the entire front/back surface of the photocatalyst filter 3 . Although it is provided on both the front and back sides in this example, it may be provided on only one side.

The dust collection filters 4A and 4B have a multi-layered structure, and a white filter layer is formed on the side facing the photocatalyst filter 3, and the light emitted from the light irradiation unit 5 to the front and back surfaces of the photocatalyst filter 3 is reflected by the facing surface and is efficiently irradiated to the front and back surfaces. Like the photocatalyst filter 3, the white filter layer preferably supports a photocatalyst. As a result, the filter layer has a catalytic function in addition to collecting and reflecting dust, and the dust and the like trapped in the filter layer and the air passing through can be cleaned by the photocatalytic action. The photocatalytic action of the filter layer on the opposing surface side can also decompose viruses and the like trapped in other outer filter layers.

A dark-colored filter layer containing activated carbon is formed in the middle of the dust collection filters 4A and 4B or on the outer side opposite to the facing surface, and is configured to efficiently capture dust and odorous components in the air and prevent light from leaking to the outside. Such a filter layer is composed of a layer in which activated carbon particles are supported by coating or the like, and thereby can be a dark-colored layer.

As shown in FIG. 7, the photocatalyst filter 3 may be constructed by combining a plurality of divided structures. In this case, it is also a preferred embodiment to interpose a reflecting plate 8 between them as shown in the figure, or to further interpose a light irradiation section 5 . In particular, when the area is large, the light irradiation from the end portion may not be sufficient. The shape of the photocatalyst unit 2 and the dust collection filters 4A and 4B is not limited to the plate shape shown in FIGS.

8 and 9 show an embodiment configured in a tubular shape. The photocatalyst filter 3 is formed into a tubular shape as shown in FIG. 8 by rolling the photocatalyst filter 3 into a cylindrical shape with one of the front and back surfaces facing inward and rolling it around an axis parallel to the direction in which each of the peaks 31 and the valleys 32 extends, and then overlapping and joining the peaks 31 or the valleys 32 at both ends. A ring-shaped light irradiation unit 5 that emits light toward the photocatalytic filter 3 is provided on one or both of the upper end side and the lower end side in the direction in which the peaks 31 and the valleys 32 extend.

The light source mounting base 52 of the light irradiation unit 5 includes a base portion 520 to which the light source 51 composed of an LED element arranged on a hollow disc-shaped substrate is mounted on the filter 3 side surface, and a pair of flat tubular support pieces 521 extending from the inner and outer peripheral edges thereof toward the filter 3 side.

Further, a fluid supply path 70 for supplying fluid to the inner surface of the photocatalyst filter 3, a fluid discharge path 71 for discharging the fluid discharged from the outer surface of the photocatalyst filter 3, and cylindrical dust collection filters 4A and 4B, which are installed inside the fluid supply path 70 and the fluid discharge path 71 and provided facing the front and back surfaces of the photocatalyst filter 3, are provided.

According to this example as well, both the inner and outer surfaces of the cylindrical photocatalytic filter 3 are irradiated with light from the upper and lower light irradiation portions 5 along the direction in which the peaks 31 or the valleys 32 extend, while the fluid is allowed to pass through the filter 3 in the thickness direction, for example from the inside to the outside, through the fluid supply path 70 and the fluid discharge path 71, so that harmful substances and odors in the fluid can be efficiently decomposed and removed by the photocatalyst supported on the front and back surfaces of the filter and the inner surface of the fluid passage hole.

FIG. 10 shows an embodiment in which the photocatalyst filter 3 and the dust collection filters 4A and 4B are disc-shaped. 10(a), the photocatalyst filter 3 is formed into a disc shape as shown in FIG. A cylindrical light irradiation unit 5 that emits light toward the photocatalytic filter 3 is provided at one or both of the inner and outer ends in the direction in which the peaks 31 and the valleys 32 extend.

The light source mounting base 52 of the light irradiation unit 5 includes a base portion 520 to which the light source 51 composed of LED elements arranged on a flat cylindrical substrate is mounted on the inner/outer peripheral surface of the filter 3 side, and a pair of hollow disc-shaped support pieces 521 extending from the upper and lower ends toward the filter 3 side.

Furthermore, a fluid supply path 70 for supplying fluid to the upper surface of the photocatalyst filter 3, a fluid discharge path 71 for discharging fluid discharged from the lower surface of the photocatalyst filter 3, and disk-shaped dust collection filters 4A and 4B, which are installed inside the fluid supply path 70 and the fluid discharge path 71 and provided facing the front and back surfaces of the photocatalyst filter 3, are provided.

According to this example as well, the upper and lower surfaces of the disk-shaped photocatalyst filter 3 are irradiated with light from the inner and outer light irradiation portions 5 along the direction in which the peaks 31 or the valleys 32 extend, while the fluid is allowed to pass through the filter 3 in the thickness direction, for example, from the upper side to the lower side through the fluid supply path 70 and the fluid discharge path 71, so that harmful substances and odors in the fluid can be efficiently decomposed and removed by the photocatalyst carried on the front and back surfaces of the filter and the inner surface of the fluid passage hole.

Although the embodiments of the present invention have been described above, the present invention is by no means limited to such embodiments, and can of course be embodied in various forms without departing from the gist of the present invention.

REFERENCE SIGNS LIST 1 fluid purification structure 2 photocatalyst unit 3 photocatalyst filter 4A, 4B dust collection filter 5 light irradiation unit 6 housing 7 light shielding wall 8 reflector 31 peak 32 valley 33 fluid passage hole 34 bridge 35 upright piece 36 end surface 40 end surface 50 lens 51 light source 52 light source mount 70 fluid supply path 71 fluid discharge path 520 base portion 521 support piece

Claims (2)

a photocatalyst filter made of a corrugated metal member in which a plurality of peaks and valleys are alternately formed, in which fluid passage holes for passing a fluid are formed in one or both of the tops of the peaks and the bottoms of the valleys, and a photocatalyst is supported on the front and back surfaces;
A photocatalyst unit provided at one or both of one end side and the other end side of the photocatalyst filter in the direction in which the peaks and valleys extend and irradiating ultraviolet light or visible light toward the inside where the peaks and valleys extend,
The light irradiation unit
A metal light source mounting base having a substantially U-shaped or U-shaped cross section, having a plate-shaped base portion arranged oppositely along one or the other end face of the photocatalytic filter to which the light source for irradiating light is mounted, and a pair of support pieces extending to the front side and the back side of the photocatalyst filter from the respective edge sides of the front side and the back side of the photocatalyst filter and fixed to the front side or the back side, respectively.
A photocatalyst unit characterized in that a rod-shaped lens is provided between the light source of the base portion and the end face of the photocatalyst filter opposed to the light source of the light irradiating portion for condensing the light from the light source in the direction of the end face. 2. The photocatalyst unit according to claim 1 , wherein a plate made of a dissimilar metal having better thermal conductivity than the metal forming the light source mount is joined to the outer surface of the base portion of the light irradiation portion, which is opposite to the surface facing the end surface of the photocatalytic filter.

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