JP2608477B2 - Discharger for ozone generation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a discharger for generating ozone.

[Conventional technology]

Ozone is obtained by performing discharge in dry air, has a strong oxidizing power, and is used for deodorization, sterilization, bleaching, and the like.

As such an ozone generating device, for example, a device in which a discharge is sandwiched by a dielectric made of alumina ceramics as disclosed in Japanese Patent Publication No. 55-37483 has been used. Further, as shown in JP-A-59-44797 and the like, a planar induction electrode is formed inside a derivative made of ceramics, and a linear discharge electrode is formed on the surface, and between these electrodes. A device that generates a creeping discharge by applying a high-frequency voltage has also been used.

Furthermore, in the ozone generating discharge body formed by forming the above-described induction electrode and discharge electrode, the discharge electrode is easily consumed during discharge, and thus a protective layer made of glass is formed to cover the discharge electrode. (See JP-A-63-66880).

[Problems of the Related Art] However, the above-mentioned protective layer made of glass has a problem that it is easily eroded by electric discharge, and the amount of ozone generated gradually decreases.

Therefore, it is considered to use various ceramics as the material of the protective layer. In this case, if the protective layer is thin, it is difficult to manufacture, and pinholes are easily generated.
Conversely, if the protective layer is thick, there are problems such as the discharge characteristics being deteriorated and the amount of generated ozone being reduced. In addition, when the type of ceramic is different, the optimum thickness is also different, so that it is very difficult to adjust the thickness of the protective layer.

[Means for solving the problem]

The present invention in view of the above, as well as a protection layer is formed to cover the discharge electrode of the ozone generating discharge body, the ratio of the capacitance C ₂ of the capacitance C ₁ and the protective layer of the dielectric layer C It has been found that if ₁ / C ₂ ≦ 0.5, the amount of generated ozone can be increased.

The above is a dielectric layer capacitance C ₁ of is that the capacitance between the dielectric layer interposed therebetween formed planar induction electrode and the linear discharge electrode, whereas the capacitance of the protective layer the C _2, when placing the same size of the electrode and the planar induction electrode on the protective layer is that this electrode of the electrostatic capacitance between the discharge electrodes.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 (a) and 1 (b) show a discharge element for ozone generation, in which an unfired ceramic plate 1 has a planar induction electrode 3 and another unfired ceramic plate 2 has a linear discharge electrode 4. Each of them is formed by applying a paste of tungsten, molybdenum, or the like, and after laminating these ceramic plates 1 and 2, a protective layer 5 made of ceramics is printed and sprayed so as to cover the discharge electrode 4, a CVD method, a PVD method. It is formed by baking and the like and the whole is integrated by firing. In the ozone generating discharger, the ceramic plate 2 serves as a dielectric layer and the induction electrode 3
When a voltage is applied between the electrode and the discharge electrode 4, creeping discharge occurs, and ozone can be generated.

As another example, as shown in FIG. 2 (a), the ozone generating discharger shown in FIGS. 2 (a), 2 (b), and 2 (c) first has tungsten, After forming a planar induction electrode 13 made of molybdenum or the like, a ceramic layer 12 as a dielectric layer is printed, sprayed, formed by a CVD method, a PVD method, or the like so as to cover the induction electrode 13, and then formed on the ceramic layer 12. A linear discharge electrode 14 made of tungsten, molybdenum, or the like is formed, and a protective layer 15 made of ceramics is formed by the same means as described above so as to cover the discharge electrode. Since this ozone generating discharge body uses the ceramic layer 12 formed by coating as a dielectric layer,
The discharge characteristics can be improved by reducing the thickness of the dielectric layer.

Next, in the ozone generating discharge body shown in FIGS. 2 (a), (b) and (c), the material and thickness T ₁ of the ceramic layer 12 as the dielectric layer and the material and thickness T ₂ of the protective layer 15 were changed. Various samples were fabricated, and the capacitances C ₁ and C ₂ of the dielectric layer and the protective layer were measured, and the actual amount of ozone generated was examined.

Note that the capacitance C ₁ of the dielectric layer is the capacitance between the dielectric electrodes 13 and the discharge electrode 14, the same as the induction electrode 13 on the upper surface of the protective layer 15 and the capacitance C ₂ of the protective layer This is the capacitance between the electrode and the discharge electrode 14 when a large-sized electrode is placed.

The induction electrode 13 is 5 mm × 20 mm, and the discharge electrode 14 is 1 mm.
It is formed of tungsten with a size of × 17.5mm, and the conditions at the time of ozone generation are as follows.
The amount of ozone generated when applied for seconds was examined.

First, the experimental results when both the dielectric layer 12 and the protective layer 15 are formed of alumina ceramics are shown in Table 1 and FIG. In addition, this alumina ceramics
92% Al ₂ O ₃ and the remainder were made of SiO ₂ , MgO, CaO, etc., and the dielectric constant was 9.5.

From Table 1 and FIG. 3 showing the relationship between C ₁ / C ₂ and the amount of generated ozone, the capacitance ratio C ₁ between the dielectric layer and the protective layer is clearly shown.
/ C ₂ decreases extremely ozone generation amount becomes larger than 0.4, in particular C ₁ / C ₂ is seen to be a 0 almost larger than the amount of ozone generated 0.5.

Next, Tables 2 and 3 show experimental results when mullite having a dielectric constant of 6.8 was used as the material of the dielectric layer and the protective layer.

The results in Tables 2 and 3 are also the same as those in Table 1. When the ratio C ₁ / C _{2 of the} capacitance between the dielectric layer and the protective layer is larger than 0.4, the amount of ozone generation decreases extremely, In particular, when C ₁ / C ₂ was larger than 0.5, the amount of generated ozone was almost zero.

Also, for example, comparing No. 3 in Table 1 and No. 2 in Table 3, both have substantially the same thickness of the dielectric layer and the protective layer, but differ in the material of the protective layer. Because the capacitance ratio C ₁
/ C ₂ is also different, but also different from the amount of ozone generated. That is, it has been confirmed that the amount of ozone generated is determined not by the ratio of the thickness of the dielectric layer to the thickness of the protective layer but by the ratio of the capacitance.

Furthermore, in the above example, only alumina and mullite were used as ceramic materials, but similar results were obtained using various materials such as forsterite, steatite, zircon, and titania ceramics. .

Thus, in the ozone generating discharge body to form a protective layer of ceramic on the discharge electrodes, in order to increase the ozone generation amount, regardless of the type of ceramic, the dielectric layer capacitances C ₁ and the protective layer of Capacitance C ₂ ratio C ₁ / C ₂
It was found that the best value was 0.5 or less, and in particular, it was best if C ₁ / C ₂ was 0.4 or less.

However, this is only from the viewpoint of the amount of generated ozone, and from the viewpoint of protection of the discharge electrode, the larger the thickness of the protective layer, the better. Therefore, actually, the capacitance ratio C ₁ / C ₂
Is within 0.5 or less, the thickness of the protective layer may be maximized.

Also, the capacitance C ₁ of the dielectric layer and the capacitance C ₂ of the protective layer are:
Each is theoretically determined by the following equation.

C ₁ = ε ₀・ ε ₁・ S / T ₁ C ₂ = ε ₀・ ε ₂・ S / T ₂ From these two equations, C ₁ / C ₂ = ε ₁ · T ₂ / ε ₂ · T ₁ Therefore, in order to reduce C ₁ / C ₂ , either increase the dielectric constant ε ₂ of the protective layer or increase the thickness T ₂ It can be seen that should be reduced. The thickness T ₂ of the protective layer is difficult to 15μm is less than the production, but problems such as voids are easily generated occurs such a case, the thickness T ₂ With the large material of dielectric constant epsilon ₂ Can be increased, and the above problem can be solved.

〔The invention's effect〕

According to the present invention as described above, a protective layer is formed so as to cover a linear discharge electrode of an ozone generating discharger,
The capacitance C ₁ of the dielectric layer the ratio of the capacitance C ₂ of the protective layer
By setting C ₁ / C ₂ ≦ 0.5, it is possible to prevent erosion of the linear discharge electrode without deteriorating the discharge characteristics and the amount of ozone generation, and to have a small change in the amount of ozone generated for a long period of time for high performance ozone generation. A discharge body can be provided.

[Brief description of the drawings]

FIG. 1 (a) is an exploded perspective view showing an ozone generating discharge body according to an embodiment of the present invention, and FIG. 1 (b) is an X- line in FIG.
It is an X-ray sectional view. 2 (a) and 2 (b) are perspective views each showing a manufacturing process of a discharge element for ozone generation according to another embodiment of the present invention.
FIG. 2 (c) is a sectional view taken along line YY in FIG. 2 (b). FIG. 3 is a graph showing the relationship between the ratio C ₁ / C _{2 of the} capacitance between the dielectric layer and the protective layer in the ozone generator of the present invention and the amount of ozone generated. 1,11: ceramic plate, 2,12: dielectric layer 3,13: induction electrode, 4,14: discharge electrode 5, 15: protective layer

Claims (1)

(57) [Claims] 1. An ozone generating discharger comprising an induction electrode and a discharge electrode sandwiching a dielectric layer, wherein a protective layer is formed so as to cover the discharger, and a capacitance of the dielectric layer is formed. ozone generating discharge body the ratio of the capacitance C ₂ of the C ₁ and the protective layer, characterized in that the C ₁ / C ₂ ≦ 0.5.