JPH08267058A - Ultraviolet ray irradiation device - Google Patents

Abstract

PURPOSE: To provide an ultraviolet ray irradiation device low in deterioration of the ultraviolet strength irradiated to a matter to be treated and capable of exhibiting a treating function of UV radiation over the entire range of a water to be treated circulating in a glass pipe. CONSTITUTION: This device is composed of a cylindrical closed vessel 2, two pairs of electrodes 3 provided extendedly along an axial direction of the closed vessel 2 at a nearly central part of the closed vessel 2 and presenting a square sectional plane, of which the corners are rounded, and 20 glass pipes 4 for circulating a water to be treated which is provided around the electrode 3 and having 3.5mm diameter and 0.7mm wall thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet irradiation device. More specifically, in addition to TOC decomposition that decomposes and removes organic substances in water by irradiating primary cooling water of a nuclear power plant or ultrapure water for semiconductor production with ultraviolet rays,
The present invention relates to an ultraviolet irradiation device used in various water treatment devices. The water to be treated to which the present ultraviolet irradiation device is applied includes not only low-viscosity fluids such as water but also high-viscosity fluids and liquids in which solids such as particles and powders are dispersed.

[0002]

2. Description of the Related Art Ultraviolet rays are absorbed by these substances while decomposing organic substances and water itself while passing through water. The degree of absorption is large with vacuum ultraviolet rays. That is, since the depth at which ultraviolet rays can reach the inside of the water to be treated is as shallow as about 100 μm, it is difficult to remove TOC in the water to be treated at a deeper depth. Therefore, special measures are required to effectively irradiate the entire water to be treated with ultraviolet rays. Therefore, it may be possible to stir the water to be treated by separately providing a stirrer, but the mechanism becomes complicated and a sufficient effect cannot be expected. Therefore, it becomes necessary to reduce the thickness of the water layer in the ultraviolet irradiation direction as much as possible.

On the other hand, the excimer ultraviolet irradiation device is provided with a glass tube or the like having ultraviolet transparency for the purpose of physically isolating the object to be processed from the electrode and for preventing the escape of the enclosed gas such as rare gas or halogen gas. So to speak, a window member (hereinafter represented by a glass tube) is incorporated. Quartz glass, CaF ₂ or the like is generally used as the material of the glass tube.

However, the ultraviolet rays emitted by the inter-electrode discharge are partially absorbed by the glass tube material when passing through the glass tube. Therefore, if the thickness of this glass tube is made too thick, the intensity of the ultraviolet rays with which the object to be treated is reduced will decrease the processing efficiency.

Therefore, an increase in the amount of water to be treated has been demanded in all directions. For that reason, if the diameter of the glass tube is increased, the thickness of the water to be treated which ultraviolet rays should pass through becomes large and the pressure resistance is maintained. Because of this, the glass thickness must be increased.

In any case, the intensity of ultraviolet rays during use is reduced. Further, in order to improve the ultraviolet ray transmittance of the glass tube, in the case of quartz glass, high purity is required and it becomes expensive, and it becomes more expensive as it becomes larger. For CaF ₂ also becomes expensive since it is a single crystal, also possible to manufacture a large-sized article is almost impossible.

The present invention has been made to solve the above problems, and a large capacity can be achieved at a low cost by reducing the diameter and thinness of the glass tube through which the water to be treated is circulated and arranging a large number thereof. An object of the present invention is to provide an ultraviolet irradiation device capable of efficiently irradiating ultraviolet rays to the entire water to be treated without significantly reducing the ultraviolet intensity.

[0008]

An ultraviolet irradiating device of the present invention comprises a hermetically sealed container in which a gas that excimates by discharge energy and emits ultraviolet light is sealed, and at least a pair of electrodes mounted in the hermetically sealed container. It is composed of a large number of thin and thin glass tubes through which water to be treated, which is installed in a closed container, flows.

Then, the closed container is formed into a substantially cylindrical shape, the electrode is provided at an approximately central portion of the closed container along the axial direction of the closed container, and the glass tube is closed around the electrode. It is preferable to arrange them along the axial direction because the assembling is easy and the water to be treated can be efficiently irradiated with ultraviolet rays.

Further, if a water distribution chamber communicating with all the glass tubes is formed at least at the upstream end of the upstream end and the downstream end of the plurality of glass tubes, not only the water supply is convenient, but also each glass is provided. This is preferable in that it is possible to distribute an equal amount of water to be treated to the pipes and to easily distribute the water to be treated to each glass pipe in a turbulent state. Of course, it is obvious that it is convenient to take out the treated water when a water collecting chamber communicating with the downstream ends of all the glass tubes is also provided.

Further, it is preferable to form a glass lining layer on the surface of the electrode in order to prevent a silent discharge or a corona discharge from being transferred to an arc discharge, because a protective layer with less risk of peeling can be formed. .

Further, it is preferable to make the electrode hollow and to equip the cavity of the electrode with a coolant supplying means for supplying and discharging a coolant so as to prevent the electrode from being heated by the discharge from being damaged and to cool the electrode. This is preferable in that the discharge efficiency can be improved.

[0013]

According to the ultraviolet irradiation apparatus of the present invention, since the glass tube has a small diameter, the thickness of the water layer of the water to be treated becomes small.
That is, it is possible to reduce the ratio of the water to be treated in the region where the ultraviolet rays are hard to reach at a depth of about 100 μm or more from the surface, so that the TOC removal efficiency is improved. Further, since the water to be treated can be made to flow in a turbulent state by using the small diameter glass tube, the contact portion of the water to be treated with the glass tube is constantly updated. Thereby, the irradiated ultraviolet rays can effectively act. In this way, since the action of treating ultraviolet rays is exerted on almost all of the circulating treated water, no special mechanism such as stirring of the treated water is required. Moreover, since the glass tube through which the water to be treated circulates is thin, the intensity of the ultraviolet rays irradiated to the object to be treated is not significantly reduced. As a result, the manufacturing cost of the device can be reduced, and highly efficient processing can be maintained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ultraviolet irradiation device of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic vertical sectional view showing an embodiment of the ultraviolet irradiation apparatus of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 1 shows an ultraviolet irradiation device 1
And a cylindrical closed container 2, two pairs of electrodes 3 (see FIG. 2) arranged along the axis of the closed container 2 at substantially the center of the closed container 2, and two pairs of electrodes 3. Twenty glass tubes 4 arranged along the axis of the closed container 2 (see FIG. 2).
See) and. A high-frequency high-voltage power supply 5 is connected between the electrodes 3 of each pair, and a discharge is generated between the electrodes 3 by energization. Due to the energy of this discharge, ultraviolet rays having a wavelength peculiar to the gas (a rare gas, a halogen gas, a mixed gas thereof, or the like) sealed in the closed container 2 are emitted.

The water W to be treated reaches each glass tube 4 from the water supply port 6 through the water distribution chamber 7 formed at one end of the closed container 2, and is irradiated with ultraviolet rays to be collected at the other end of the closed container 2. It is taken out from the outlet 9 through the water chamber 8.
Not only can the equal amount of water to be treated W be sent to each glass tube 4 by providing the water distribution chamber 7, but also after the water to be treated W once fills the water distribution chamber 7, the flow direction is changed to each glass tube 4. By flowing in, a turbulent flow is likely to be formed, and the ultraviolet irradiation part is frequently updated.

In the present embodiment, the diameter is 3.5 mm and 0.7
A glass tube 4 with a wall thickness of mm is used. And 2
Zero glass tubes 4 are arranged around the two pairs of electrodes 10 at equal intervals along two concentric circles. The glass tube is not limited to the above size, and may be appropriately selected depending on the amount of water to be treated, the length of the glass tube, and the like. Further, the number of glass tubes is not limited to 20.

Further, the arrangement of the glass tubes is not limited to that shown in FIG. 2, and any arrangement may be used as long as the ultraviolet rays due to the energy of the discharge between the electrodes 3 are evenly applied to all the glass tubes.

In the present embodiment, two pairs of electrodes 3 are provided, but the present invention is not limited to two pairs, and one or three or more pairs may be provided depending on the amount of water to be treated and the like.

As shown in the figure, the outer surface of the electrode 3 is provided with a glass lining 10. This is to cause normal corona discharge and silent discharge and prevent transition to arc discharge. For this purpose, the glass lining is most suitable because the risk of peeling and breakage is extremely small.

Further, the electrode 3 is hollow,
The coolant is configured to flow into the internal cavity 3a. This is because the heating of the electrode due to the energy applied by the discharge can be suppressed to prevent damage, and the electrode can be cooled to improve the discharge efficiency. As the cooling agent, known ones such as cold water and ethylene glycol are used. In this embodiment, the ends of the electrodes 3 are communicated with each other by the tubes 11 as shown in the figure so that the coolant flows in a series between the pair of electrodes 3.

However, the present invention is not particularly limited to the series connection, and a coolant may be flown into each electrode 3 individually, that is, in parallel.

Further, although the closed container 2 is formed in a cylindrical shape in this embodiment, the present invention is not limited to a cylindrical shape. For example, it may be a rectangular tube or the like.

A reflective coating 12 is formed on the inner peripheral surface of the closed container 2 so as to reflect the generated ultraviolet rays. The reflective coating is not limited to being directly formed on the inner surface of the closed container 2, and a reflective plate may be installed along the inner surface of the closed container 2, for example. This reflective coating 12 (or reflector) preferably totally reflects ultraviolet rays,
For example, a metal material with aluminum vapor-deposited on its entire surface, a metal material with a polished surface, a high-temperature oxidation treatment after polishing, and a wet etching treatment with an acid solution, and a dielectric multilayer film on the reflecting surface. It is possible to use a reflecting mirror coated with or a mirror in which the glass portion is quartz glass.

It is obvious that the ultraviolet irradiation device of the present invention can be applied not only to a low-viscosity fluid but also to a high-viscosity fluid and an object to be treated in which solids such as granules and powders are dispersed.

[0027]

EFFECTS OF THE INVENTION According to the present invention, the ultraviolet irradiation portion for the same amount of water to be treated is much increased as compared with the conventional case.
Therefore, the treatment effect of ultraviolet rays is exerted on almost all the water to be treated flowing through the glass tube, and no special mechanism such as stirring of the water to be treated is required. Moreover, the decrease in the intensity of ultraviolet light applied to the object to be treated is small. As a result, the manufacturing cost of the device can be reduced and highly efficient processing can be performed.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing an embodiment of an ultraviolet irradiation apparatus of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 ... Ultraviolet irradiation device 2 ... Airtight container 3 ... Electrode 4 ... Glass tube 10 ... Glass lining

Claims (5)

[Claims] 1. A hermetically sealed container in which a gas that excimates by discharge energy and emits ultraviolet rays is enclosed, at least a pair of electrodes mounted in the hermetically sealed container, and water to be treated provided in the hermetically sealed container flows. An ultraviolet irradiator comprising a large number of thin and thin glass tubes. 2. The closed container has a substantially cylindrical shape, the electrode extends along the axial direction of the closed container in a substantially central portion of the closed container, and the electrode is provided around the electrode. The ultraviolet irradiation device according to claim 1, wherein the glass tubes are arranged along the axial direction of the closed container. 3. The ultraviolet irradiation device according to claim 1, wherein a water distribution chamber communicating with all the glass tubes is formed at least at an upstream end of the upstream ends and the downstream ends of the plurality of glass tubes. 4. The ultraviolet irradiation device according to claim 1, wherein a glass lining layer is formed on the surface of the electrode. 5. The ultraviolet irradiation device according to claim 1, wherein the electrode is hollow, and a coolant supplying means for supplying and discharging a coolant is provided in the cavity of the electrode.