JP2818051B2 - Air purifier also serves as a heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air
For purifiers, more specifically, a warmer with a deodorizing function
The present invention relates to an air purifier also serving as a chamber.

[0002]

2. Description of the Related Art Electric heaters used in conventional hot air generators are roughly classified into the following two types. (1) A device using a metal-based electric resistor. (2) A device using a positive characteristic ceramic heater element. Both of these heaters have a sufficient function as a heater, but usually do not have a deodorizing function. However, recently, with use at home, a hot air generator having a deodorizing function has been demanded. For example, deodorization of tobacco and the like in a room by an electric hot air heater, and deodorization of odors from foods during cooking in cooking equipment, particularly in a convection type microwave oven. Therefore, the present inventors have previously proposed a ceramic heater having both a heater function and a deodorizing function (Japanese Utility Model Application No. 2-12).
227).

[0003]

However, the ceramic heater proposed above has the following problems since only the noble metal catalyst is supported on the surface of the ceramic heater. (1) When the heater temperature is low, the catalytic effect is not sufficient and the deodorizing property is poor. (2) When used as a hot air heater, it can be deodorized when hot air is generated in winter, but cannot be used as a deodorizer when hot air in summer is unnecessary.

In order to solve these problems, it is conceivable to use ozone deodorization, which is a method capable of deodorizing even at ordinary temperature, in combination with a ceramic heater. This method is already used in a deodorizing device of a refrigerator, and is a method of decomposing odor contained in air passing through the ventilation path by installing an ultraviolet lamp and a photo-excited catalyst in the ventilation path ( JP-A-60-187322 and JP-A-62-252875).

[0005] However, when such a ceramic heater and a photo-excited catalyst are used together for deodorization, both a honeycomb-shaped ceramic heater as a heating element and a carrier for supporting the photo-excited catalyst are required, and the structure is complicated. Not only that, it has the disadvantage that it requires a large volume and is expensive.

The present invention has been made under such circumstances, and in particular, to provide a ceramic heater which is excellent in deodorizing performance, has a high deodorizing effect even when the heater temperature is low, and can be used only as a deodorizer. It is assumed that.

[0007]

According to the present invention, there is provided a porous conductive ceramic containing silicon carbide as a main component.
And a ceramic heater made of a sintered body.
Means for blowing air to the heater, and a surface of the ceramic heater
Photo-excited catalyst particles supported on
Also serves as a heater consisting of ultraviolet irradiation means for irradiating outside light
An air purifier is provided.

[0008] The air purifier which also serves as the heater of the present invention is provided.
The porous conductive ceramic sintered body of the ceramic heater is obtained by subjecting particles of silicon carbide (SiC) to heat collective sintering in a non-oxidizing atmosphere (for example, in nitrogen or argon). Here, in addition to silicon carbide, particles such as silicon nitride (Si ₃ N ₄ ) may be contained, and any ceramic sintered body mainly composed of silicon carbide functioning at least as a ceramic heater may be used.

[0009] The form of the sintered body is a honeycomb shape. Such a honeycomb shape includes not only a hexagonal lattice shape but also various lattice shapes such as a square lattice shape, a triangular lattice shape, and a circular lattice shape. A sintered body of such a form can be obtained by extrusion molding in a corresponding mold and performing the collective sintering.

According to the present invention , the photoexcited catalyst particles are supported on the surface of the SiC-based ceramic sintered body.
Ceramic heater can be obtained that.

Here, the photo-excited catalyst particles mean particles which can be activated by light energy and photochemically decompose odor components. For example, a p-type inorganic semiconductor capable of generating holes and oxidizing and decomposing an odor component by irradiation of light energy such as ultraviolet light, and fine particles of an n-type inorganic semiconductor having an opposite effect to the above are exemplified. As Ti
O _2, Z _n O, include S _n O ₂ or the like.

For example, in the case of an inorganic oxide-based photoexcited catalyst, an aqueous solution containing a corresponding inorganic ion, inorganic acid ion, hydroxide or the like is deposited on the surface of the SiC-based ceramic sintered body. It can be carried out by precipitating it as an oxide or hydroxide by impregnation or coating and then subjecting it to high-temperature heat treatment. The amount of the carrier is, for example, 20 to ^{1 with} respect to a honeycomb molded body outer size capacity of 1000 cm ³ .
About 00 g is appropriate.

In addition, the noble metal particles are also supported on the surface of the photo-excited catalyst particle-carrying ceramic heater by impregnating the surface with an aqueous solution of a noble metal (for example, platinum, palladium, rhodium, etc.) in the same manner as described above. It can be performed by processing.

The ceramic heater thus obtained
Is usually provided with a pair of electrodes, and is disposed in a predetermined gas flow path together with a power supply system and light energy applying means (for example, an ultraviolet lamp) as necessary.

[0015]

The ceramic heater of the air purifier also serving as the heater according to the present invention is made of a conductive SiC-based material. Since the particles are carried, a deodorizing function is exhibited by irradiating light energy such as ultraviolet rays.
In particular, since the structure is a honeycomb shape, the surface area is large, the efficiency as a heater for generating hot air is excellent, and the catalytic effect is also excellent. When air containing odor comes into contact with the honeycomb heater during irradiation with light energy such as ultraviolet rays for the purpose of deodorization, the odor is decomposed by the photoexcited catalyst on the surface. When noble metal catalyst particles are further supported on the photoexcited catalyst particles, the activity of the photoexcited catalyst is improved, and when heated as a heater, deodorization due to the catalytic action of the noble metal catalyst without irradiation with ultraviolet rays or the like. can do.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An air purifier also serving as a heater according to the present invention will be described below.
Further is a description of an embodiment, the present invention,
It is not limited to these embodiments. Heating of the present invention
A method of manufacturing an air purifier also serving as a purifier will be described below.

Silicon carbide powder (average particle size 5.5 μm) 7
0 parts by weight, metal silicon powder (average particle size 5.9 μm)
30 parts by weight, 21 parts by weight of water were added to a total of 12 parts by weight of a methylcellulose organic resin binder and a fatty acid sorbitan ester polyethylene glycol as a molding aid,
Mix for about 5 minutes with a mixer. After sufficiently kneading this mixture with a continuous kneader, a rectangular honeycomb having an outer size of 140 × 40 mm, a cell size of 2.2 × 2.2 mm, and a rib thickness of 0.5 mm was formed at a molding pressure of 60 kg / cm ² by a high-pressure vacuum extruder. Extrusion molding, drying after cutting to appropriate dimensions, then debinding in a nitrogen atmosphere at 500 ° C for 3 hours, and then reaction sintering in a nitrogen atmosphere at 1400 ° C for 6 hours, from a composite of silicon carbide and silicon nitride. Thus, a porous ceramic sintered body was formed.

This honeycomb sintered body is immersed in an aqueous solution containing a titanium compound (a raw material of a photoexcited catalyst), and titanium dioxide or titanium hydroxide is supported on the surface of a porous ceramic sintered body. Baked at about 500 ° C to obtain titanium dioxide particles (photo-excited catalyst particles)
Was obtained on the surface of the ceramic heater of the present invention (sample A).

Thereafter, the above sintered body is immersed in an aqueous solution of platinum acid and treated in the same manner as described above to thereby obtain another ceramic of the present invention in which platinum particles (noble metal catalyst particles) are further supported on the outermost surface. A heater (sample B) was obtained.

Each of the samples A and B was cut to a thickness of about 15 mm, and an aluminum film was formed on two opposing surfaces by thermal spraying to form electrodes.

FIG. 1 is an explanatory view of the ceramic heater prepared as described above. The honeycomb heater 1 has a normal temperature resistance 12
Ω (having NTC characteristics of 8.3Ω at about 250 ° C.), the outer electrodes 140 (width) × 40 (height) × 15 (depth) mm, and the electrodes 2 facing each other in the height direction are formed. A voltage is applied to the electrode 2 via the lead plate 3 to generate heat. The cell 4 is a hole surrounded by a rib 5 having a size of 2.2 × 2.2 mm and a thickness of 0.5 mm and penetrates in the depth direction. FIG. 2 is a schematic diagram when a photoexcited catalyst is supported on the surface of the honeycomb heater 1 or when a platinum-based catalyst is further supported on the surface. In this way, fine silicon nitride particles 7a and silicon nitride fibers 7b, which are nitrided, surround the SiC particles 6 through the gaseous silicon once, and the surface of these fine particles 7 is photo-excited by titanium dioxide. The catalyst particles 8 are supported (FIG. 2 (b): A part enlarged view). In FIG. 2C, platinum particles 9 as noble metal-based catalyst particles are further supported on the surface of the fine silicon nitride particles 7 or the surface of the photoexcited catalyst particles 8.

FIG. 3 is an explanatory view of a hot air generator having a deodorizing function using a photo-excited catalyst using the ceramic (honeycomb) heater 1 shown in FIG. Cold air containing odor is sent in. UV lamp 13 installed in ventilation path 12
Of the honeycomb heater 1 is efficiently radiated to the honeycomb heater 1 by the reflection plate 14. When the cold air containing the odor sent into the air passage 12 passes through the honeycomb heater 1,
By contacting the photoexcited catalyst particles supported on the surface and activated by ultraviolet light, the odor component is decomposed, and the air becomes almost odorless and cool.

That is, when energy equal to or more than the band gap due to ultraviolet light is applied to the photoexcited catalyst, which is a substance that converts light energy into chemical energy and is a semiconductor,
Electrons in the valence band jump into the conduction band and become bipolarized, and excited electrons and holes generated in the valence body induce a chemical reaction. For example, slight hydroxyl groups existing on the surface of the photoexcited catalyst are converted into OH radicals by holes, and odor components are oxidatively decomposed by the oxidizing power of the OH radicals having a higher oxidizing power than ozone or the like. Ultraviolet rays are used as excitation light rays, but since ultraviolet rays originally have a bactericidal activity, nucleic acids in cells of suspended bacteria in the passing air are inactivated and destroyed, and the passing air is used. Can be sterilized.

When the honeycomb heater 1 is used for heating, an odorless warm air is generated by applying an alternating current of 100 V to the electrode 2 formed on the honeycomb heater 1. When the air flow rate is 0.8 m ^{3 /} min, the average hot air temperature is about 120 ° C. (at room temperature of 20 ° C.), the average temperature of the heater is about 250 ° C., and the electric power is 1200 W.

When platinum particles are carried on the outermost surface, deodorization can be performed during heating without irradiation with ultraviolet rays. This is because the honeycomb heater 1 that generates cold air containing odor is generating heat.
This is because, when passing through, the heated platinum particles 9 come into contact, and as a result, they are directly oxidized and deodorized by the platinum particles 9 and can emit warm air almost odorless. Naturally, at this time, if deodorization with a photoexcited catalyst is also used,
The deodorizing effect is further improved, and the sterilizing effect is also improved by heat and ultraviolet rays.

[0026]

According to the present invention, a ceramic heater made of a porous conductive ceramic sintered body containing silicon carbide as a main component, a blowing means for blowing air to the ceramic heater, and a supporter for supporting the ceramic heater on the surface thereof Since the photo-excited catalyst particles and the ultraviolet light irradiating means for irradiating the photo-excited catalyst particles with ultraviolet light, the conductive ceramic sintered body has a function as a heating element and a deodorizing and sterilizing method by using a combination of light energy such as ultraviolet light. It can have both functions. Also,
Since the photoexcited catalyst particles are carried on the ceramic heater surface, when operated as a heater and an air purifier,
In addition, even when the air conditioner is operated only as an air purifier without using a ceramic heater, the odor component and dust attached to the ceramic heater or the photocatalyst surface are constantly or periodically heated to generate heat. Can be disassembled and removed. Therefore, even when the air purifier is used for a long time, the odor component can always be reliably decomposed. Further, by carrying a noble metal-based catalyst particle such as platinum on the outermost surface, a normal oxidation catalyst function can be exhibited. Therefore, according to the present invention, it is possible to provide an all-season type air purifier that can also be used as a heater especially in winter.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the configuration of a ceramic heater according to an embodiment of the present invention.

FIG. 2 is a schematic view of the ceramic heater of the present invention supporting photoexcited catalyst particles and noble metal-based particles on the outermost surface.

FIG. 3 is a configuration explanatory view illustrating a hot air generator having an air purifying machine function using the ceramic heater of the present invention.

[Description of Signs] 1 Ceramic heater 2 Electrode 3 Lead wire 4 Cell 5 Rib 6 SiC particle 7 Silicon nitride particle 8 Photoexcited catalyst particle 9 Platinum particle 10 Motor 11 Fan 12 Ventilation path 13 Ultraviolet lamp 14 Reflector

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B01J 21/00-38/74 B01D 53/36

Claims (2)

(57) [Claims] 1. A ceramic heater comprising a porous conductive ceramic sintered body containing silicon carbide as a main component;
A means for blowing air to the mic heater;
Photo-excited catalyst particles supported on the surface of
Heating comprising ultraviolet irradiation means for irradiating particles with ultraviolet light
An air purifier that doubles as a machine. 2. The empty space serving also as a heater according to claim 1 , wherein noble metal catalyst particles are carried on the surface of the ceramic heater.
Air purifier.