JPH094900A - Range hood utilizing operation of photocatalyst of tio2 - Google Patents

Abstract

PURPOSE: To provide a range hood having an oil decomposition function. CONSTITUTION: A fan 2 on the surface of which TiO2 is applied is contained in a hood case 1 on the inner surface of TiO2 is applied and a ceramic filter 3 carrying TiO3 is arranged in front of a fan 2. Ultraviolet radiation is directed to the ceramic filter 3 from a light source 4. The light source 4 is arranged in the hood case 1 in such a manner that the light source parts from the ceramic filter 3 together with a reflection plate 5 where occasion demands and during decomposition of oil, the light source approaches the ceramic filter 3. Since oil adhering to the hood case 1, the fan 2, and the ceramic filter 3 is decomposed through operation of a photocatlyst, this constitution eliminates a need of cleaning and keeps a range hood in a clean state for a long time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hood having a TiO ₂ coating which exhibits a self-cleaning function.

[0002]

2. Description of the Related Art In a kitchen or the like, a range hood for discharging smoke generated in a range to the outside is provided in order to maintain a comfortable living space. However, conventional range hoods are difficult to remove dirt such as oil adhesion. In addition, dirt such as oil adhering to the exhaust port and surrounding walls significantly deteriorates the appearance of the building. In order to prevent such oil stains, a filter is incorporated in the range hood. However, a range hood using a metal filter has a low adhesion efficiency of floating oil, and the oil accumulated on the surface of the filter gradually drips, which is also a drawback. Therefore, recently, as a disposable filter, one in which ceramic paper or the like is attached to the surface of a metal filter has come to be used. However, it is inevitable that some oil will still pass through the filter. The oil that has passed through the filter adheres to the inner surface of the range hood box, which has a complicated internal structure, and the fan. To make it easier to wipe off the adhered oil,
A range hood with a fluororesin coating on the inside is also used.

[0003]

As a filter such as ceramic paper, it is necessary to have a coarse mesh so as not to cause a decrease in air flow. However, coarse filters are less efficient at capturing flying oil. Also,
Since the filter is disposable, it takes time to replace the filter, and the cost becomes high. Also, the oil that has passed through the filter and adhered to the inner surface of the range hood box and the fan is very difficult to clean due to the complicated internal structure, and tends to remain inside. The present invention was devised to solve such a problem, and TiO ₂ having a function of decomposing adhered oil
It is an object of the present invention to provide a range hood that is kept clean for a long period of time by coating.

[0004]

In order to achieve the object, the range hood of the present invention has a hood case whose inner surface is coated with TiO ₂ and a hood case which is housed in the hood case and whose surface is coated with TiO ₂ coating. Equipped with a fan, a ceramics filter placed in front of the fan and carrying TiO ₂ , and a light source for irradiating the ceramics filter with ultraviolet light, and separated from the ceramics filter during cooking and the ceramics filter during oil decomposition. The light source is movably provided on the hood case so as to be close to the hood case. In order to increase the irradiation efficiency of ultraviolet rays, it is preferable to dispose a reflection plate near the light source at a position opposite to the ceramics filter with the light source as the center. This reflector can be incorporated into a front panel swingably provided on the hood case. Alternatively, it is possible to provide the drawer with a light source and a reflection plate, and press the drawer to expose the light source and the reflection plate to the ceramics filter.
Further, a metal filter coated with TiO ₂ can be used instead of the ceramic filter supporting TiO ₂ .

[0005]

When the TiO ₂ powder is irradiated with ultraviolet rays, crude oil and salad oil are decomposed. Although the detailed mechanism of the decomposition action of TiO ₂ is not clear, it is presumed as follows. By irradiation with ultraviolet rays, electrons in the valence band of TiO ₂ absorb energy and are excited into the conduction band, where they react with oxygen to generate highly active O radicals, such as O ₂ ⁻ . On the other hand, the holes generated in the valence band due to the excitation of electrons react with the hydroxyl group (—OH) from the water adsorbed on the catalyst surface to generate an OH ⁻ radical. These active radicals react with the oil component and efficiently decompose the oil component. In the present invention, by utilizing this behavior, Ti activated by ultraviolet irradiation is used.
Various studies were conducted on the decomposition of oil adhered to the range hood by O ₂ . As a result, when a metal or ceramic filter carrying TiO ₂ is used as a filter for a range hood and a metal plate coated with TiO ₂ is used as a case of a range hood or an outer plate of a fan, a self-cleaning action with an oil decomposition function is obtained. A range hood that exhibits is obtained.

Further, since the amount of oil decomposition increases in proportion to the intensity of ultraviolet rays, when a reflector having a high reflectance is used,
Even if the same light source is used, the ultraviolet intensity can be improved. Specifically, when using an Al-coated steel sheet having a reflectance of 40 to 80% by finishing, TiO ₂ is irradiated with high UV intensity and the oil content is efficiently decomposed. In the present invention, TiO ₂ that exhibits a photocatalytic action is used.
The ceramics filter carrying is used. T
When iO ₂ is irradiated with ultraviolet rays, the oil generated during cooking and the oil adhering to the filter surface are decomposed and CO, CO
₂ , H ₂ O, H ₂ etc. are removed. As TiO ₂ , any of rutile, anatase, brookite and the like can be used, but of these, anatase type TiO ₂ is preferable. A low-pressure mercury lamp, a high-pressure mercury lamp or the like is used as a light source for irradiating the TiO ₂ coating with ultraviolet rays.

The filter for supporting TiO ₂ is not particularly limited in material, and various ceramic filters are used. However, since a ceramics filter using an acrylic resin as a binder tends to be deteriorated by ultraviolet rays when it is irradiated with ultraviolet rays, it is preferable to use a urea resin having excellent ultraviolet resistance as a binder. A ceramic filter using a urea resin as a binder maintains excellent performance for a long period of time. TiO ₂ is supported by immersing the ceramics filter in the TiO ₂ powder dispersion or sol and drying. The supported amount of TiO ₂ is selected in the range of 1 to 200 g / m ^{2 based on} the surface area of the filter. If the supported amount is less than 1 g / m ² , TiO will be exposed even by UV irradiation.
The oil degrading effect of ₂ is hardly exhibited. Conversely, 200
If the supported amount exceeds g / m ² , the filter is likely to be clogged, which causes a reduction in the wind speed of the range hood due to pressure loss.

The trace amount of oil that has passed through the filter adheres to the inner wall of the range hood and the fan. In particular, since this part is difficult to clean, it is necessary to use a metal plate having a TiO ₂ coating on the surface. As a coating method in this case, a sol-gel method, an electrophoretic electrodeposition method, thermal spraying, vapor deposition, sputtering or the like is adopted. However, it is effective to set the coating conditions so that the coated TiO ₂ is anatase type with high oil decomposing ability. As the metal plate, ordinary steel, stainless steel, plated steel plate, coated steel plate, etc. are used. In particular, A
The 1-plated steel sheet exhibits an effect of efficiently reflecting the ultraviolet rays and improving the oil decomposing ability even when the ultraviolet rays applied to the TiO ₂ are not absorbed and reach the surface of the metal plate. On the surface of this metal plate, in order to obtain a predetermined oil resolution, 0.3-2
A TiO ₂ coating layer is formed with a film thickness of 0 μm.
If the TiO ₂ coating layer is thinner than 0.3 μm, sufficient oil decomposition efficiency cannot be obtained. However, in the case of a thick TiO ₂ coating layer having a thickness of more than 20 μm, not only the oil decomposing ability of TiO ₂ is saturated, but also the formed coating layer is easily separated from the metal plate.

[0009] In the present invention, assembling the range hood with this way the metal plate having a ceramic filter or TiO ₂ coating carrying TiO ₂ in. Specifically, as shown in FIG. 1, a range hood case 1
Is made of a metal plate whose inner surface is coated with TiO ₂ . Inside the case 1, the TiO ₂ coated fan 2 is arranged. A ceramic filter 3 using a urea resin carrying TiO ₂ as a binder is arranged in the front opening of the case 1 in front of the fan 2. A light source 4 for irradiating ultraviolet rays is opposed to the ceramics filter 3, and a reflecting plate 5 for improving the irradiation efficiency from the light source 4 is arranged at a position opposite to the ceramics filter 3 as necessary. The light source 4 and the reflector 5 are swingably attached to the case 1, and are housed on the inner surface side of the front panel 6 during cooking as shown in FIG. When the adhered oil is decomposed, it is brought into contact with the surface of the filter 3 as shown in FIG. Then, ultraviolet rays are emitted from the light source 4 to start cleaning. As a result, the oil adhering to the ceramics filter 3 is decomposed without being exposed to harmful ultraviolet rays. Further, the ultraviolet light emitted from the light source 4 passes through the ceramics filter 3 and the oil content attached to the inner surface of the case 1 and the fan 2 is also decomposed.

For a drawer type range hood, a ceramic filter 3 is arranged in front of the fan 2 provided inside the case 1 as shown in FIG. The inner surface of the case 1 and the surface of the fan ₂ are coated with TiO ₂ . As the ceramics filter 3, one carrying TiO ₂ is used. A light source 4 for irradiating ultraviolet rays is installed in the lower part of the case 1, and a reflection plate 5 is provided below the case 1. At the time of cooking, as shown in FIG. 2A, the fan 2 is pulled out from the hood case 1 by the handle to bring the fan 2 into an operable state, and the generated oil smoke is captured by the ceramic filter 3. Figure 2 after cooking
As shown in (b), the fan 2 is pushed in, the operation of the fan 2 is stopped, and the irradiation of ultraviolet rays from the light source 4 is started. As a result, the oils are decomposed by the TiO ₂ carried on the ceramics filter 3, and the oils attached to the inner surface of the case 1 and the fan 2 are decomposed by the TiO ₂ coating. Even in this case, ultraviolet rays do not leak to the outside,
The range hood is restored to a clean condition.

[0011]

[Example] Using a ceramics filter of various binders, the amount of TiO ₂ supported was 10 g / m ² , and the amount of oil deposited was 5
The oil content was decomposed by irradiating ultraviolet rays with a low-pressure mercury lamp of 15 W as g / m ² . The oil decomposition was continued for 150 hours under the condition of replenishing the reduced oil content every 24 hours.
Then, the clean state of the filter due to the difference in the binder was investigated. The results of the investigation are shown in Table 1 depending on the type of binder used. As is clear from Table 1, in the epoxy resin and vinyl acetate resin, deterioration of the binder was observed, and the fiber retention ability of the ceramic filter was lost. On the other hand, a ceramic filter using urea resin as a binder has sufficient durability,
Oil resolution continued for a long time.

[0012]

Example 2: For a ceramic filter using urea resin as a binder, the oil adhesion amount was 20
Ti under the conditions of g / m ² and UV intensity of 6.2 mW / cm ^2.
The effect of the loading amount on the oil decomposition characteristics was investigated. As can be seen in Table 2 showing the investigation results, the loading amount of TiO ₂ is 1 to
In the range of 200 g / m ² , decomposition of oil was confirmed, and the oil decomposition rate increased according to the amount of TiO ₂ supported. However, 0.
No effective oil cracking was detected with TiO ₂ loading as low as 5 g / m ² . On the other hand, the amount of TiO ₂ supported is 250 g /
The m ² filter showed the same oil decomposition rate as the case of the carried amount of 200 g / m ² , but rather a decrease in wind pressure was observed when the range hood was installed.

[0014]

Example 3: The metal portion of the fan and the inner surface of the case of the range hood were coated with TiO ₂ with various film thicknesses. Then, the oil adhesion amount is set to 1 g / m ² and 7c
Ultraviolet rays were radiated from a 15 W low-pressure mercury lamp placed at a distance of m, and the oil decomposition rate after 24 hours was investigated. The results of the investigation are summarized in Table 3 by the film thickness of the TiO ₂ coating. As can be seen in Table 3, no oil degrading effect was detected when the film thickness of the TiO ₂ coating did not reach 0.3 μm. On the other hand, in the TiO ₂ coating having a film thickness of more than 20 μm, the oil decomposition rate was not improved in proportion to the increase in the film thickness. From this, TiO that is effective for oil decomposition
It can be seen that the film thickness of the ₂ coating is in the range of 0.3 to 20 μm.

[0016]

Example 4 The effect of the reflector on the irradiation efficiency and thus on the oil decomposition rate was investigated. A 15 W low-pressure mercury lamp was used as a light source, and the oil decomposition rate after 24 hours was measured under the conditions of TiO ₂ supported amount of 12.2 g / m ² and oil adhesion amount of 10 g / m ² . The measurement results are shown in Table 4 according to the type of reflector used. As shown in Table 4, when stainless steel was used as the reflector, the oil decomposition rate was almost the same as that without the reflector even with mirror finish. On the other hand, Al
When using foil, Al plate, Al coated steel plate, etc.,
Oil decomposition efficiency increased significantly. This indicates that the Al surface has a high reflectance and the ultraviolet rays from the light source are efficiently applied to the ceramics filter.

[0018]

Example 5: The effect of the type of lamp attached to the range hood on the oil decomposing ability was investigated. TiO ₂
Under the conditions of a supported amount of 10 g / m ² and an oil adhesion amount of 10 g / m ² , the irradiation distance was kept at 7 cm and the oil decomposition rate after 24 hours was measured. As the light source, a fluorescent lamp that emits visible light of 20 W, a low-pressure mercury lamp that emits ultraviolet rays with a wavelength of 254 nm, and a high-pressure mercury lamp that emits ultraviolet rays with a wavelength of 352 nm were used. The measurement results of the oil decomposition rate are summarized in Table 5 according to the type of lamp and shown in Table 5. As seen in Table 5, oil decomposition due to photocatalytic reaction was not detected in the fluorescent lamp.
On the other hand, when using a low-pressure mercury lamp and a high-pressure mercury lamp as the light source, the oil decomposition rates after 24 hours are 33% and 25%, respectively.
And showed a high value.

[0020]

[0021]

As described above, according to the present invention, Ti
Utilizing the photocatalytic action of O ₂ , the range hood has a self-cleaning function. That is, the oil smoke generated during cooking is caught by the filter without being discharged to the outside, and the attached oil is decomposed by irradiating the filter with ultraviolet rays. Therefore, the range hood according to the present invention does not need to be cleaned to remove the adhered oil, there is no concern that the exhaust port will be contaminated with oils, and the range hood can be used for a long time without replacing the filter. Also, a small amount of oil adheres to the inside of the hood case, but this is also decomposed by the photocatalytic action of the TiO ₂ coating, and the inside of the hood is kept clean.

[Brief description of drawings]

FIG. 1 is a range hood in which a light source and a reflector are swingably provided, showing a cooking state (a) and a cleaning state (b).

FIG. 2 is a range hood in which a light source and a reflector are provided inside a drawer type, showing a state (a) during cooking and a state (b) during cleaning.

[Explanation of symbols]

1: Case 2: Fan 3: Ceramics filter 4: Light source 5: Reflector 6: Front panel

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Umeda 7-1 Takaya Shinmachi, Ichikawa City, Chiba Nisshin Steel Co., Ltd.

Claims (2)

[Claims] 1. A hood case having an inner surface coated with TiO ₂ and a hood case housed in the hood case and having a T surface on the surface.
a fan iO ₂ coating is applied, is arranged in front of the fan, and a metal filter that ceramics filter or TiO ₂ coated carrying TiO _2,
A TiO ₂ is provided in the hood case so that the light source is movable so that the ceramic filter is provided with a light source for irradiating ultraviolet rays, and is separated from the ceramic filter during cooking and is close to the ceramic filter during oil decomposition. Range hood using the photocatalytic action of. 2. A range hood in which a reflector is arranged near the light source at a position opposite to the ceramics filter with the light source according to claim 1 as a center.