JP2002126066A - Deodorizing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deodorizing device of which rate of deodorizing is great and which is compact as well as does not exert a harmful effect upon a human body. SOLUTION: This deodorizing device comprises a fan 2 that generates an air flow from a suction inlet to an blowing outlet, an ozone generating device 5 that is placed in an upper stream of the air flow, a photocatalyst member 4 that is placed in the downstream compared to the ozone generating device 5 and is air permeable, and a LED light source 3 that irradiates a short wavelength light to the photocatalyst member 4. Ozone changes into an active species with high oxidizing activity by the photocatalyst by which a bad smell causative substance is decomposed at a rapid rate. The LED is so compact and a lighting circuit is also compact that it is possible to make it small. In addition, using the LED emitting a short wavelength light of 360-400 nm allows preventing generation of an intermediate generated by a photodecomposition of ozone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing apparatus which is disposed in a house, a warehouse, an automobile, a refrigerator, a clog box and the like and removes odorous substances from the air.

[0002]

2. Description of the Related Art In an environment where people live, various odor-causing substances are generated, and therefore, it is often necessary to deodorize air in order to provide a comfortable living environment. For example, in a newly-built house, formaldehyde odor generated from adhesives and paints used for building materials has become a problem, and switching to adhesives and paints that do not use formaldehyde has been performed. In addition, deodorants are used as needed because refrigerators, toilets, shoe boxes, and the like also emit odor.

[0003] The best way to remove the odor-causing substance in the air and deodorize it is to prevent the odor-causing substance from being generated. However, the odor due to the excretion from the human body during human life It is difficult to prevent the generation of unpleasant odor or the like from food. In addition, the removal of odor-causing substances by reaction with chemicals and the adsorption of odor-causing substances to adsorbents such as activated carbon have also been performed.
In any case, since the effect is reduced due to consumption or saturation of the amount of adsorption, there is a problem that it is necessary to periodically replace the new one and maintenance is troublesome.

[0004] In recent years, a method for removing an odor-causing substance using a photocatalyst has been proposed, and several air purifiers using the same have been proposed. For example, JP-A-11-27
Japanese Patent No. 6564 discloses an air purifying apparatus including a gas permeable photocatalyst member, a fan, and a light source.

In this air purifying apparatus, an ultraviolet lamp is used as a light source, and the photocatalyst is activated by irradiating the ultraviolet light. The odor-causing substance in the air passing through the air-permeable photocatalyst member by the fan is oxidized and decomposed by the activated photocatalyst, and the deodorized air is blown out.

Therefore, according to this air cleaning device,
Deodorization can be performed continuously without any need for regular replacement. The publication also states that UV lamps have a wavelength of 200
It is disclosed that ozone is generated from air by generating ultraviolet light of nm or less. By doing so, the deodorizing action is further improved by both the ozone and the photocatalyst, and the antibacterial action by the ozone is also exhibited.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No. 11-27
In the air purifying apparatus disclosed in the publication No. 6564, an ultraviolet lamp such as a black light, an insect lamp, a germicidal lamp or the like is used as a light source. Was difficult to make compact. Therefore, it is difficult to provide a device that can be installed in a refrigerator or a shoe box, and further miniaturization is required.

When an ultraviolet lamp that generates ozone is used, the generated ultraviolet light is harmful to the human body, so that it is necessary to make it invisible to humans. Ozone is harmful to the human body and is further harmful by irradiation with ultraviolet light. In some cases, an intermediate may be produced, which limits its use.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a compact deodorizing apparatus which has a high deodorizing speed, has no adverse effect on the human body.

[0010]

According to a first aspect of the present invention, there is provided a deodorizing apparatus comprising: a substantially cylindrical base having an air inlet and an air outlet; A fan that generates an airflow toward the airflow, an ozone generator disposed on the base body upstream of the airflow, a photocatalyst member disposed downstream of the ozone generator and capable of transmitting air, and a photocatalyst member disposed on the basebody. An LED light source that emits short-wavelength light.

The LED light source is preferably made of a gallium nitride based optical semiconductor having a sharp emission intensity peak at a wavelength of 360 to 400 nm.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a deodorizing apparatus according to the present invention, air is introduced into a substrate from an air inlet by the rotation of a fan, passes through a photocatalyst member, and is blown out from an air outlet. Since the photocatalyst member is irradiated with short-wavelength light from the LED light source,
When the air passes through the photocatalyst member, the odor-causing substance in the air is decomposed by the photocatalyst of the photocatalyst member, and is blown out from the outlet as clean air.

[0013] However, the oxidation reaction by the photocatalyst generally has a low reaction rate, depending on the type of the substance to be oxidized. Therefore, the deodorizing device of the present invention includes an ozone generator upstream of the photocatalyst member. The direct reaction rate between ozone and the odor-causing substance is generally slow, and has the disadvantage that the reactivity decreases as the decomposition proceeds. However, by combining ozone with a photocatalyst and a light source, ozone is converted into active species by photolysis and photocatalysis. Since the oxidizing activity of this active species is extremely high, the odor-causing substance can be decomposed at a high reaction rate.

Further, the odor-causing substance in the air comes into contact with the photocatalyst in a state where it is partially oxidized by ozone. Therefore, the oxidizing action by the photocatalyst is more effectively expressed, and the odor-causing substance can be decomposed at a high reaction rate. Therefore, according to the deodorizing apparatus of the present invention, it is possible to deodorize at a deodorizing speed twice or more as compared with a conventional deodorizing apparatus using a photocatalyst or a deodorizing apparatus using ozone.

[0015] Even if ozone not consumed by the odor-causing substance or an intermediate produced by photodecomposition of ozone remains, the ozone or intermediate is decomposed by the photocatalyst, so that harmful ozone or intermediate is produced. The body is prevented from being contained in the air blown out from the outlet.

Further, in the deodorizing apparatus of the present invention, an LED light source for irradiating short-wavelength light is used as a light source for activating the photocatalyst. This LED light source has a wavelength of 360-400nm
It is desirable to use an LED having a sharp emission intensity peak. By using such an LED, emission of harmful ultraviolet rays having a wavelength of 300 nm or less can be avoided. Furthermore, such wavelengths 360-400
The light of nm has low energy and is effective for activating the photocatalyst, but hardly causes the photolysis reaction of ozone. Therefore, the active species generated by the decomposition reaction of ozone by the photocatalyst can be used for the decomposition of the odor-causing substance, and the generation of harmful intermediates generated by the photolysis of ozone can be suppressed.

By the way, the light emitted by an LED, unlike a semiconductor laser, generally has a spectral range of at least 50 nm. Therefore, it is difficult to obtain an LED that emits only light having a wavelength of 360 to 400 nm, and generally also emits visible light. However, even if the light has a wavelength of 400 nm or less (ultraviolet light), the light up to about 380 nm has a hazy background (dark purple).
Even when only light having a wavelength of 400 nm or less is emitted, the light is not completely black light, but is generally visible. Therefore, if the arrangement is designed so that the light emission of the light source can be directly viewed, the purple emission of the LED can be viewed, and the design can be improved and the LED can be used as illumination.

The LED is a very small light emitting element and has a low operating voltage, so that it can emit light even from a dry cell or the like. Therefore, since the LED and its lighting circuit do not require much space for installation, the light source unit can be formed in a very compact structure. As such an LED, a pn-junction gallium nitride (GaN) -based optical semiconductor crystal provided on a sapphire substrate is optimal.

The photocatalyst member may be a substrate made of, for example, a honeycomb body or an open-cell foam, in which a photocatalyst is attached to at least a wall surface of an air passage. Alternatively, a particulate photocatalyst may be filled in a holder formed of a wire mesh. In some cases, a photocatalyst may be attached to a dust filter made of corrugated paper or the like, so that the dust filter also functions as a photocatalyst member.

As the photocatalyst, TiO ₂ , WO ₃ , CdS, Sr
Known materials such as TiO ₃ and MoS ₂ can be used,
In consideration of the safety and the degree of activity, it is particularly desirable to use TiO ₂ . As the crystal structure of TiO ₂ , any of rutile type and anatase type can be used, but the anatase type having high catalytic activity is preferable.

In the above-mentioned photocatalyst member, the photocatalyst itself is preferably porous. As a result, the contact area with air is further increased, so that the deodorizing efficiency is further improved.

The photocatalyst member desirably contains an adsorbent such as activated carbon, zeolite, and silica gel in addition to the photocatalyst. Thereby, the odor-causing substance and ozone can be adsorbed. This adsorbent can be used as a powder mixed with a photocatalyst powder. It is also preferably made of those thin photocatalyst such as TiO ₂ on the surface of the adsorbent such as activated carbon and zeolites.

By including the adsorbent as described above, the odor-causing substance can be adsorbed, and the adsorbed odor-causing substance can be decomposed by the photocatalyst and ozone. In addition, since ozone is also adsorbed by the adsorbent, a reaction between ozone and the odor-causing substance or a reaction between the photocatalyst and the odor-causing substance occurs on the surface of the photocatalyst member. Therefore, it is effective when purifying air containing a large amount of odor-causing substances, and since the adsorbed substances are consumed by the reaction, there is no need to replace the adsorbent.

On the surface of spherical glass such as silica gel
It is also preferable to use photocatalyst particles formed of a thin photocatalyst such as TiO ₂ . By doing so, the amount of light transmitted through the photocatalyst particles increases, and the utilization efficiency of the photocatalyst improves.

In the case of photocatalyst particles, since there is almost no restriction on the direction of light irradiation from the LED light source, the degree of freedom in the arrangement of the photocatalyst member and the light source is high. Air to be deodorized also passes through the gap between the particles and the particles themselves,
There are few restrictions on the direction of air flow. Therefore, by optimally selecting the arrangement shape of the photocatalyst member, it is possible to secure the maximum deodorizing efficiency while keeping the ventilation resistance small.

The ozone generator is not particularly limited as long as it can generate ozone stably, but it is desirable to use an ozone generator using a solid polymer film which generates ozone by supplying electric power. Such an ozone generator can generate ozone at a low voltage, and thus can be reduced in size and weight. Therefore, the deodorizing apparatus of the present invention using the same can be downsized. In addition, ozone is generated stably even in a humid environment,
Since NO _x and discharge noise is not generated, it is suitable for deodorizing device for a motor vehicle.

The arrangement of each member in the deodorizing apparatus of the present invention is such that the ozone generator is located on the upstream side of the photocatalyst member and the light from the LED light source is irradiated on the photocatalyst member. Is not particularly limited. However, in order to suppress the direct decomposition reaction due to the light absorption of ozone, it is desirable that the LED light source is disposed downstream of the photocatalyst member. The position of the fan is not limited as long as the fan generates an airflow from the intake port to the air outlet.

[0028]

The present invention will be described below in detail with reference to examples.

(Embodiment) FIG. 1 shows a deodorizing apparatus according to one embodiment of the present invention. This deodorizing device is assumed to be installed in an automobile. This deodorizing device includes a cylindrical base 1,
It comprises a fan 2, an LED light source 3, a photocatalyst member 4, and an ozone generator 5.

The fan 2 is fixed to the outlet 11 of the base 1,
When driven by a DC 5V power supply, an airflow from the air inlet 10 to the air outlet 11 is formed.

The LED light source 3 includes a plurality of LEDs 31
Is fixed in the base body 1 near the outlet 11. The substrate 30 has a net shape, and allows air to flow. The plurality of LEDs 31 are made of a gallium nitride-based optical semiconductor pn-joined on a sapphire substrate, and are turned on by a DC voltage of 3.5 to 4 V, respectively.
It emits short wavelength light with a sharp emission intensity peak at a wavelength of 380 nm.

The photocatalyst member 4 is formed by corrugating a sheet to which a mixed powder of a TiO ₂ powder as a photocatalyst and an adsorbent powder such as silica gel is adhered (manufactured by Mitsubishi Paper Mills) and has a large surface area. And a low pressure loss. The photocatalyst member 4 is fixed inside the base 1 on the upstream side of the LED light source 3.

As the ozone generator 5, as shown in FIG. 2, an "ultra-small ozonizer" (manufactured by Ryoden Kasei Co., Ltd.) which generates ozone from water and oxygen by applying a voltage to a solid polymer film is used. ing. This ultra-small ozonizer
It has a module size of 45 × 48 × 5 mm and is extremely small. And about 0.2V by applying 3V DC voltage
It produces ozone at mg / cm ² / hr. The ozone generator 5 is held in a suspended state in the base body 1 near the intake port 10 on the upstream side of the photocatalyst member 4, and air introduced from the intake port 10 flows into the base body 1 from around the microminiature ozonizer module. I do.

The ozone generator 5 is provided with a constant current circuit (not shown) for stably driving the microminiature ozonizer.

In the deodorizing apparatus of the present embodiment configured as described above, the air containing the offensive odor-causing substance flows into the base 1 from the intake port 10 by the rotation of the fan 2 and passes through the ozone generator 5. It goes to the photocatalyst device 4. Ozone is generated from the ozone generator 5, and the ozone is mixed into the inflowing air.

On the other hand, in the LED light source 3, the LED 31 is turned on, and the photocatalyst member 4 is irradiated with short-wavelength light, so that the TiO ₂ attached to the photocatalyst member 4 is activated. When air containing ozone flows into the myriad of passages of the photocatalyst member 4, the activated TiO ₂ decomposes ozone to generate active species, which quickly oxidize and decompose the odor-causing substance. At the same time, the reaction was slow but activated
A decomposition reaction of the malodor causing substance by TiO _{2 and} a decomposition reaction of the malodor causing substance by ozone occur.

A part of the odor-causing substance and a part of the ozone are adsorbed by the adsorbent adhering to the photocatalyst member 4.
The adsorbed odor-causing substance is quickly decomposed and removed by the ozone in the air stream or the adsorbed ozone and TiO ₂ . This reaction occurs on the surface of the adsorbent adhering to the photocatalyst member 4, and the adsorbent recovers its adsorbing ability by decomposition of the adsorbed substance. Therefore, there is no need to replace the adsorbent.

Further, a photolysis reaction of ozone also occurs.
Since the ED light source 3 and the ozone generator 5 are separated by the photocatalyst member 4, the amount of the intermediate produced by the photolysis of ozone is small. The ozone itself and the intermediate produced by the photolysis of ozone are decomposed and detoxified by the activated TiO ₂ .

The clean air from which the odor-causing substances are removed and the harmful substances such as ozone are removed is passed through the LED light source 3 and discharged from the outlet 11.

Comparative Example 1 A deodorizing apparatus having the same configuration as that of the embodiment except that the ozone generator 5 was not provided was used as a comparative example.

Comparative Example 2 LED Light Source 3 and Photocatalyst Member 4
A deodorizing device having the same configuration as that of the example except that the deodorizing device was not provided was used as a comparative example.

<Test / Evaluation> The deodorizing apparatuses of the examples and comparative examples 1 and 2 were each placed in a 3 liter closed container. Air containing acetaldehyde at a concentration of 3500 ppm is sealed in the closed container. Then, each deodorizing device was driven for 60 minutes, and the acetaldehyde concentration in the closed container was measured with the lapse of the driving time. The results are shown in FIG. FIG. 4 shows the result of repeating the above test.
Shown in The fan 2 is driven at 5 V and 0.6 A, respectively, and the air flow rate in the base 1 is 0.052 m ³ / min.

FIG. 3 shows that the deodorizing apparatus of Comparative Example 2 has a low decomposition rate of acetaldehyde, and it is difficult to quickly deodorize with only ozone. In addition, in the deodorizing apparatus of Comparative Example 1, the decomposition rate of acetaldehyde is higher than that of Comparative Example 2, and the decomposition rate by the photocatalyst is higher than that of ozone.

However, comparing Example and Comparative Example 1,
In the deodorizing apparatus of the embodiment, the decomposition rate of acetaldehyde in the initial stage is extremely high. Since the sum of the measured values of Comparative Examples 1 and 2 does not reach the measured value of the example, it is clear that the deodorizing apparatus of the example has a synergistic effect of ozone and a photocatalyst.

FIG. 4 shows that the deodorizing device of the example, like the deodorizing device of Comparative Example 1, did not decrease in deodorizing performance even by repetition, and showed stable deodorizing performance. Also, according to the deodorizing apparatus of the example, it can be seen that the amount of acetaldehyde that can be deodorized in the same time is about twice or more as compared with the comparative example 1.

[0046]

That is, according to the deodorizing apparatus of the present invention, the deodorizing speed is extremely high, no harmful substances are generated, and maintenance is free. Further, since it can be made compact and uses only a small amount of electric power, the degree of freedom of its use is high.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a deodorizing apparatus according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of an ozonizer used in a deodorizing device according to one embodiment of the present invention.

FIG. 3 is a graph showing the test results of the deodorizing apparatuses of Examples and Comparative Examples, and showing the relationship between elapsed time and acetaldehyde concentration.

FIG. 4 is a graph showing the repetition test results of the deodorizing apparatuses of the examples and the comparative examples, and showing the relationship between the elapsed time and the acetaldehyde concentration.

[Explanation of symbols]

1: Base 2: Fan
3: LED light source 4: Photocatalyst member 5: Ozone generator 1
0: Inlet 11: Outlet 30: Substrate 3
1: LED

Continued on the front page F term (reference) 4C080 AA07 AA09 BB02 CC01 HH05 JJ03 KK08 LL10 MM02 MM08 NN04 NN05 NN06 QQ17 QQ20 4D048 AA22 AB01 BA07X BA15Y BA16Y BA26Y BA27Y BA41X BA42Y BA46Y BB02 BB09 CB02 CB02

Claims (2)

[Claims] 1. A substantially cylindrical base having an inlet and an outlet.
A fan disposed on the base to generate an air flow from the intake port to the air outlet; an ozone generator disposed on the base on an upstream side of the air flow; and a downstream disposed from the ozone generator. A deodorizing device comprising: a photocatalyst member capable of transmitting air; and an LED light source disposed on the base and irradiating the photocatalyst member with light having a short wavelength. 2. The LED light source has a wavelength of 360 to 400 nm.
The deodorizing apparatus according to claim 1, comprising a gallium nitride-based optical semiconductor having a sharp emission intensity peak.