JP7313764B2 - Ultraviolet irradiator and ozone generator - Google Patents

Description

The present invention relates to an ultraviolet irradiation device that emits ultraviolet rays using an excimer lamp.

As a method for generating ozone with strong oxidizing power, it is possible to generate ozone by irradiating a source gas containing oxygen such as air with ultraviolet rays, and an excimer lamp is used as a light source for irradiating ultraviolet rays (see Patent Document 1). In this case, an intake port is provided on the top surface of the housing, an exhaust port is provided on the bottom surface, and a fan or the like is provided at the intake port to allow air to flow into the housing.

In the excimer lamp, when the tube wall temperature of the arc tube rises, the light intensity decreases, and thermal decomposition of generated ozone occurs in the vicinity of the arc tube. In order to prevent this, it has been proposed to increase the efficiency of ozone generation by setting the flow velocity of the raw material gas flowing in the tube in which the excimer lamp is arranged to a predetermined value or higher so that the material gas flows in a laminar flow state (see Patent Document 2).

JP 2016-139462 A Japanese Patent No. 6070794

In the case of vacuum ultraviolet rays having a peak wavelength in a wavelength region of 200 nm or less, which is easily absorbed by oxygen molecules, the ultraviolet rays are significantly attenuated even if they travel a relatively short distance, resulting in a drop in the intensity of the ultraviolet rays. Therefore, it is difficult to irradiate a gas flowing in a region (space) away from the lamp surface in a tube in which an excimer lamp is arranged with ultraviolet rays having an ultraviolet intensity necessary for generating ozone.

Therefore, it is required to effectively irradiate the raw material gas flowing through the tube in which the excimer lamp is arranged with ultraviolet rays using the excimer lamp.

The ultraviolet irradiating device of the present invention can be installed in an ozone generating device, and can constitute an ozone generating device that irradiates a fluid flowing in from an inlet with ultraviolet rays and the fluid flows out from an outlet. The excimer lamp can be arranged to face an axial fan arranged downstream of the excimer lamp, or can be arranged to face an axial fan arranged upstream of the excimer lamp.

In the present invention, the maximum height of the electrodes or electrode-related members provided on the outer surface of the excimer lamp is determined to be equal to or less than the transmission distance at which the ultraviolet intensity ratio of the ultraviolet rays emitted from the outer surface of the excimer lamp is attenuated to 20%. Here, the "electrode-related member" is a member installed on the outer surface of the excimer lamp according to the electrode arrangement for the purpose of maintaining the performance of the electrode, suppressing performance deterioration, etc., and for example, a protruding member in which a conductive plate is wound in a cylindrical shape.

By lowering the height of the electrode or the electrode-related member than the travel distance of the ultraviolet rays at which the ultraviolet intensity ratio of the ultraviolet rays emitted from the outer surface of the excimer lamp is attenuated to 20%, the material gas passing near the outer surface of the excimer lamp is irradiated with ultraviolet rays having sufficient intensity. The maximum height may be equal to or less than the transmission distance at which the ultraviolet intensity ratio of ultraviolet rays emitted from the outer surface of the excimer lamp is attenuated to 50%.

Considering the ratio of the excimer lamp to the fluid tube, the separation distance from the outer surface of the excimer lamp to the inner wall of the flow path should be set to be equal to or greater than the transmission distance at which the ultraviolet intensity ratio of ultraviolet rays is attenuated to 80%. In particular, it is sufficient that the separation distance is greater than or equal to the transmission distance at which the ultraviolet intensity ratio of ultraviolet rays is attenuated to 50%.

For example, the excimer lamp may be arranged coaxially with respect to the axis of the fluid tube forming the flow path, and the outer diameter of the excimer lamp may be 4 mm or more and larger than 1/2 the inner diameter of the fluid tube.

According to the present invention, an excimer lamp can be used to effectively irradiate ultraviolet rays.

1 is a schematic configuration diagram of an ultraviolet irradiation device according to a first embodiment; FIG. It is a schematic block diagram of the ultraviolet irradiation device which is 2nd Embodiment.

Embodiments of the present invention are described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an ultraviolet irradiation device according to the first embodiment.

An ultraviolet irradiation device 10 forming part of the ozone generator 1 includes an axial fan 20 , a fluid pipe 30 and an excimer lamp 40 . The excimer lamp 40 comprises an inner tube and an outer tube made of a dielectric material such as quartz glass, and only the tubular arc tube 40A serving as the outer tube is shown here. The excimer lamp 40 emits ultraviolet rays in the wavelength range of vacuum ultraviolet rays, that is, ultraviolet rays having a wavelength of 200 nm or less, and in this case, ultraviolet rays having a peak wavelength of 172 nm.

An inner electrode is provided inside the inner tube (not shown) of the excimer lamp 40, and an outer electrode 50 is provided on the outer surface 40S of the arc tube 40A serving as the outer tube. The outer electrode 50 is composed of a conductive wire wound spirally at a predetermined pitch, and its end is connected to a power supply line (not shown).

The fluid tube 30 has an ultraviolet irradiation section, forms a flow path for the raw material gas (object to be irradiated), and the raw material gas flows from the inlet 30A toward the outlet 30B. The raw material gas is an oxygen-containing gas, and here air is allowed to flow into the fluid tube 30 . The fluid tube 30 can be formed in a cylindrical shape, for example.

The axial fan 20 includes a fan motor portion 22 and fan blades 24 , has substantially the same outer diameter as the fluid pipe 30 , and is arranged coaxially with the outlet 30</b>B of the fluid pipe 30 . The excimer lamp 40 is arranged in the fluid tube 30 such that the axis (lamp axis) of the arc tube 40A coincides with the axis C of the fluid tube 30, that is, along the axis of the axial fan 20. As shown in FIG. The arc tube 40A is supported by a support member (not shown).

As the axial fan 20 rotates, ambient air flows into the inlet 30A of the fluid tube 30 and moves along the fluid tube 30 . The excimer lamp 40 is lighted under the control of a power supply (not shown) and emits ultraviolet rays. As a result, ozone is produced, and the produced ozone passes through the outlet 30B and the axial flow fan 20 and is used for deodorization, sterilization, and the like.

In general, vacuum ultraviolet rays with a specific peak wavelength are easily absorbed in the atmosphere, and the ultraviolet rays emitted from the excimer lamp 40 are quickly attenuated and the intensity of the ultraviolet rays is lowered. The degree of this attenuation follows the magnitude of the absorption coefficient of ultraviolet rays in the atmosphere. In an ideal measurement environment, in the case of ultraviolet rays with a wavelength of 172 nm, the ultraviolet intensity ratio is attenuated to 50% or less when traveling about 3 mm, 20% or less at about 6 mm, and all the ultraviolet rays are absorbed at about 30 mm. Below, the travel distance of the ultraviolet rays when the ultraviolet rays are attenuated to a predetermined ultraviolet intensity ratio is expressed as a transmission distance L. As shown in FIG. In an actual measurement environment, it is a distance that can be grasped as attenuation of the ultraviolet intensity ratio from a state in which an ultraviolet illuminometer having sensitivity in the wavelength range of vacuum ultraviolet rays is brought close to the outer surface of the arc tube.

The air flowing into the fluid tube 30 flows along the vicinity of the outer surface 40S of the arc tube 40A of the excimer lamp 40 toward the outlet 30B. At this time, since the outer electrode 50 protrudes from the outer surface 40S, the flow along the axis C direction is less likely to occur near the outer surface 40S of the excimer lamp 40, and the flow is obstructed, resulting in increased pressure loss.

In this embodiment, the height d of the outer electrode 50 from the lamp outer surface 40S is determined to be lower than the transmission distance at which the ultraviolet intensity ratio is attenuated to 20%. Preferably, it is determined to be lower than the transmission distance at which the ultraviolet intensity ratio is attenuated to 50%. In the case of ultraviolet rays having a peak wavelength of 172 nm, the outer electrode 50 may be made of a conductive member so that the height d is 6 mm or less, more preferably 3 mm or less.

In order to irradiate the air flowing near the excimer lamp 40 with ultraviolet rays having sufficient ultraviolet intensity to generate ozone, it is preferable to minimize the distance E between the outer surface 40S of the excimer lamp 40 and the inner wall 30C of the fluid tube 30. However, even if an attempt is made to increase the efficiency of ozone generation by increasing the flow rate of the axial flow fan 20, if the ratio of the space (area) occupied by the excimer lamp 40 in the fluid pipe 30 becomes too large, the air becomes difficult to flow when passing near the excimer lamp 40, resulting in pressure loss.

In order not to increase the pressure loss of the passing air, the separation distance E from the lamp outer surface 40S to the inner wall 30C of the fluid tube 30 is set to be larger than the transmission distance at which the ultraviolet intensity ratio is attenuated to 80%. Preferably, it is determined to be larger than the transmission distance at which the ultraviolet intensity ratio is attenuated to 50%. In the case of ultraviolet rays having a peak wavelength of 172 nm, the size (outer diameter B) of the excimer lamp 40 and the inner diameter T of the fluid tube 30 are determined such that the distance E is 1 mm or more, more preferably 3 mm or more.

On the other hand, when the excimer lamp 40 is extremely thin compared to the fluid tube 30, that is, when the size of the region determined by the outer diameter B of the excimer lamp 40 relative to the size of the passage space determined by the inner diameter T of the fluid tube 30 is small, as described above, it is difficult to effectively irradiate the air flowing through the fluid tube 30 with ultraviolet rays having the intensity necessary for generating ozone. On the other hand, if the outer diameter of the excimer lamp is too small, the discharge space will also become small, and the ultraviolet intensity of the ultraviolet rays emitted from the excimer lamp will be low. Therefore, it is desirable that the outer diameter B of the excimer lamp 40 is 4 mm or more, and that the inner diameter T of the fluid pipe 30 is 1/2 or more.

As described above, according to this embodiment, in the ultraviolet irradiation device 10, the excimer lamp 40 is arranged coaxially within the fluid pipe 30 through which air flows, and the axial flow fan 20 is installed downstream. The height d of the outer electrode 50 from the lamp outer surface 40S is determined to be less than the transmission distance at which the UV intensity ratio is attenuated by 20%.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, an axial fan is arranged on the upstream side, and projection members (electrode-related members) are provided on the outer surface of the lamp.

FIG. 2 is a schematic configuration diagram of an ultraviolet irradiation device according to a second embodiment.

The ultraviolet irradiation device 100 includes an excimer lamp 40 , a fluid pipe 30 housing the excimer lamp 40 , and an axial fan 20 arranged at an inlet 30</b>A of the fluid pipe 30 . Axial fan 20 and excimer lamp 40 are arranged coaxially with respect to axis C of fluid tube 30 .

A projecting member 70 is provided at the upstream end of the outer surface 40S of the excimer lamp 40 . The projecting member 70 is constructed by winding a conductive plate cylindrically. A radial height d' of the projecting member 70 from the outer surface 40S is set to be lower than the transmission distance at which the ultraviolet intensity ratio is attenuated to 20%. Preferably, it is determined to be lower than the transmission distance at which the ultraviolet intensity ratio is attenuated to 50%.

Although the operation of the axial fan 20 increases the wind noise of the electrode-related members, the sound generated during the ozone generation is somewhat loud, so that even a user who is in a position where the warning light provided in the ozone generator 1 cannot be seen can be notified that high-concentration ozone is being discharged. For example, the axial fan 20 may be operated by configuring the electrode-related member so that a sound of 40 dB can be measured.

The excimer lamp 40 may be configured to emit vacuum ultraviolet rays having a peak wavelength other than 172 nm. Also, a centrifugal fan may be used instead of the axial fan 20 .

REFERENCE SIGNS LIST 1 ozone generator 10 ultraviolet irradiation device 20 axial fan 30 fluid tube 40 excimer lamp 50 outer electrode 70 projecting member (electrode-related member)

Claims (9)

an excimer lamp that emits ultraviolet rays having a peak wavelength of 200 nm or less;
An ultraviolet irradiation device comprising a flow path for housing the excimer lamp,
The maximum height of the electrodes or electrode-related members provided on the outer surface of the excimer lamp is equal to or less than the transmission distance at which the ultraviolet intensity ratio of the ultraviolet rays emitted from the outer surface of the excimer lamp is attenuated to 20%;
An ozone generator, wherein a fluid flowing in from an inlet of said channel is irradiated with ultraviolet rays, and the fluid flows out from an outlet of said channel. 2. The ozone generator according to claim 1, wherein said maximum height is equal to or less than a transmission distance at which the ultraviolet intensity ratio of ultraviolet rays emitted from the outer surface of said excimer lamp is attenuated to 50%. 3. The ozone generator according to claim 1, wherein the distance between the outer surface of the excimer lamp and the inner wall of the flow path is equal to or greater than the transmission distance at which the ultraviolet intensity ratio of the ultraviolet rays is attenuated to 80%. 4. The ozone generator according to claim 1, wherein the distance between the outer surface of the excimer lamp and the inner wall of the flow path is equal to or greater than the transmission distance at which the ultraviolet intensity ratio of the ultraviolet rays is attenuated to 50%. the excimer lamp is arranged coaxially with respect to the axis of the fluid tube forming the flow path;
5. The ozone generator according to any one of claims 1 to 4, wherein the excimer lamp has an outer diameter of 4 mm or more and is larger than 1/2 of the inner diameter of the fluid tube. 6. The ozone generator according to any one of claims 1 to 5, wherein the excimer lamp faces an axial fan arranged downstream of the excimer lamp. 6. The ozone generator according to any one of claims 1 to 5, wherein the excimer lamp faces an axial fan arranged upstream of the excimer lamp. 8. The ozone generator according to any one of claims 1 to 7, wherein said excimer lamp emits ultraviolet rays having a peak wavelength of 172 nm. An excimer lamp that emits ultraviolet rays having a peak wavelength of 200 nm or less is placed in the channel,
An ozone generating method for irradiating a fluid flowing in from an inlet of the flow path with ultraviolet rays and flowing out the fluid from an outlet of the flow path,
A method for generating ozone, wherein the maximum height of an electrode or an electrode-related member provided on the outer surface of the excimer lamp is set so as to be equal to or less than a transmission distance at which the ultraviolet intensity ratio of ultraviolet rays emitted from the outer surface of the excimer lamp is attenuated to 20%.

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