Ozone generating excimer lamp, ozone generating device and method for manufacturing an ozone generating excimer lamp

Abstract

To provide an excimer lamp capable of generating high-concentration ozone while suppressing the influence on equipment arranged around a lamp.SOLUTION: An excimer lamp for ozone generation includes an outer tube 20 and an inner tube. The outer surface 20S of the outer tube 20 is provided with silica particles M that deviate the traveling direction of ultraviolet rays such that the height from the inner surface to the outer surface of a discharge tube is adhered in layers over the entire surface so as to vary irregularly at least along the tube axis direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an excimer lamp that can be used in an ozone generator, and more particularly to the configuration of a discharge tube of an excimer lamp. [Background technology]

[0002] For example, in the case of an excimer lamp with a double-tube structure, a dielectric covering a foil-like inner electrode is placed inside the discharge tube, and a high-frequency voltage is applied between the outer electrode and the inner electrode provided on the outer surface of the discharge tube. This causes excimer light such as ultraviolet rays to be emitted from the discharge space formed between the dielectric and the discharge tube (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-38658 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an ozone generator, the lamp power circuit, a jacket forming a flow path, and other components are arranged around the lamp. When the lamp power is increased to increase the amount of ozone generated, the ultraviolet radiation intensity increases. Since the reach of ultraviolet rays in air is roughly proportional to the ultraviolet intensity, ozone is generated over a wider range. As a result, there is a risk of deterioration of the circuits and components around the lamp.

[0005] Therefore, there is a demand for providing an excimer lamp that is capable of generating high-concentration ozone while minimizing the impact on devices and the like placed around the lamp. [Means for solving the problem]

[0006] An excimer lamp according to one aspect of the present invention is applicable to an ozone generator, and includes a discharge tube forming a discharge space in which a discharge gas is sealed, and electrodes for applying a voltage to the discharge space, and the outer surface of the discharge tube is configured so that ultraviolet light generated in the discharge space travels in a direction deviated from the radial direction when passing through the discharge tube. Here, "a direction deviated from the radial direction" includes a case in which the traveling direction of light along a plane perpendicular to the tube axis changes to a deviated direction after passing through the discharge tube, and a case in which the traveling direction of light in any direction in three-dimensional space changes to a deviated direction after passing through the discharge tube.

[0007] For example, it is possible to form a film or layer of particles that deflect the direction of ultraviolet rays on the outer surface of the discharge tube. The "particles that deflect the direction of ultraviolet rays" have the property of reflecting and refracting ultraviolet rays. Alternatively, the particles that are adhered may be ones that cause either reflection or refraction.

[0008] The particles can be fixed to the outer surface of the discharge tube in various ways, for example, the particles can be fixed so that the height from the inner surface to the outer surface of the discharge tube varies irregularly at least along the tube axis direction. For example, the particles can be fixed to the entire outer surface of the discharge tube.

[0009] For example, the height from the inner surface to the outer surface of the discharge tube may vary by 30% or less of the wall thickness of the discharge tube. In other words, the particles may be fixed so that the height of the layer or film of the fixed particles does not exceed 30% of the wall thickness.

[0010] On the other hand, the outer surface of the discharge tube can be configured with an uneven surface whose inclination changes regularly or irregularly along the tube axis direction. For example, the uneven surface of the outer surface can be configured so that the inclination changes continuously.

[0011] In this case, the height from the inner surface to the outer surface of the discharge tube may be changed by 30% or less compared to the wall thickness when no irregularities are formed on the outer surface of the discharge tube.

[0012] Another aspect of the present invention is an excimer lamp for generating ozone, which can be applied to an ozone generator, and comprises a discharge tube made of silica glass forming a discharge space in which a discharge gas is sealed, and electrodes for applying a voltage to the discharge space, in which silica particles of uniform or non-uniform particle size are fixed to the entire outer surface of the discharge tube, and ultraviolet light generated in the discharge space travels in a direction deviated from the radial direction when it passes through the discharge tube.

[0013] A method for producing an ozone generating excimer lamp according to another aspect of the present invention includes the steps of attaching pulverized silica powder to the entire outer surface of a discharge tube and subjecting the discharge tube to a heat treatment to fix the silica powder. Effect of the Invention

[0014] According to the present invention, it is possible to provide an excimer lamp that is capable of generating high-concentration ozone while minimizing the impact on devices disposed around the lamp. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view of an excimer lamp according to a first embodiment. [Diagram 2] 2 is a schematic cross-sectional view showing a portion of the outer surface of an outer tube. FIG. [Diagram 3] FIG. 3 is a diagram showing the direction of ultraviolet radiation in the schematic cross-sectional view of FIG. 2. [Figure 4] 6 is a schematic partially enlarged cross-sectional view of an outer tube of an excimer lamp according to a second embodiment. FIG. [Diagram 5] 11 is a schematic partially enlarged cross-sectional view of an outer tube of an excimer lamp according to a third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] FIG. 1 is a schematic cross-sectional view of an excimer lamp according to the first embodiment.

[0018] The excimer lamp 10 is a discharge lamp with a double tube structure, and is disposed within a flow path tube 60 provided in an ozone generator (not shown). The flow path tube 60 is configured to allow the flow of a raw material gas (such as a gas containing oxygen) for generating ozone, or a liquid to be irradiated with ultraviolet light for sterilization or deodorization. The excimer lamp 10 is supported by a support member (not shown) provided within the flow path tube 60.

[0019] The excimer lamp 10 comprises a discharge tube (hereinafter referred to as the outer tube) 20 and an inner tube 30 arranged coaxially within the outer tube 20. The outer tube 20 is made of a material that is transparent to ultraviolet light, and in this case is made of quartz glass (silica glass).

[0020] The inner tube 30 is made of a dielectric material such as quartz glass, and is fused to the inner electrode 40 therein, so as to cover the entire inner electrode 40. A rare gas such as xenon gas or a mixed gas containing a rare gas is sealed in the discharge space S formed between the inner tube 30 and the outer tube 20 as a discharge gas.

[0021] The outer electrode 50 here is composed of a conductive wire wound in a spiral shape on the outer surface 20S of the outer tube 20. The inner electrode 40 is connected to a power supply unit (not shown) via a lead wire 45, and the outer electrode 50 is also connected to the power supply unit via a power supply line (not shown).

[0022] A voltage is applied to the inner electrode 40 and the outer electrode 50, a discharge (dielectric barrier discharge, etc.) occurs in the discharge space S, and ultraviolet rays are emitted from the discharge space S as excimer light. For example, a high frequency (e.g., several kHz) and a high voltage (e.g., several kV) are applied to the inner electrode 40 and the outer electrode 50. For example, a discharge gas is sealed in such a way that ultraviolet rays with a wavelength of 172 nm, which is suitable for generating ozone without generating NOx, are emitted.

[0023] In addition, the outer electrode 50 can be configured in such a way that foil electrodes are arranged opposite each other on the outer surface 20S of the outer tube 20 along the lamp axis E, or that a mesh-like metal wire is shaped into a tube and arranged on the outer surface 20S of the outer tube 20, as long as it is configured so that ultraviolet rays can be emitted from part or the entire outer surface 20S of the outer tube 20.

[0024] FIG. 2 is a schematic cross-sectional view showing a portion of the outer surface of the outer tube 20. As shown in FIG.

[0025] 2, silica particles M are adhered to the outer surface 20S of the outer tube 20. The silica particles M are adhered to the entire surface of both the outer surface 20S1 along the lamp axis E of the outer tube 20 and the both end surfaces 20S2 approximately perpendicular to the lamp axis E.

[0026] The silica particles M are made of, for example, the same material as the quartz glass that is the material of the outer tube 20. The particle size of the silica particles M may be set, for example, in the range of 0.1 to 100 μm, and is set, for example, in the range of 1 to 20 μm. Here, the silica particles M have a shape without acute angles and are made of silica particles M with approximately the same (uniform) particle size, but it is also possible to make the silica particles M of different particle sizes.

[0027] The silica particles M are fixed to cover the entire outer surface 20S of the outer tube 20, but due to gaps between the particles, a part of the outer surface 20S is exposed. However, the ratio of the exposed part to the entire surface area of ​​the outer surface 20S is very small, and the silica particles M can be considered to substantially cover the entire outer surface 20S of the outer tube 20.

[0028] The silica particles M cover the outer surface 20S of the outer tube 20 in a layered manner, so that the outer surface 20S of the outer tube 20 has an uneven surface shape, and a flat surface portion is not substantially formed. If the height from the inner surface 20M of the outer tube 20, including the height h from the outer surface 20S of the layered portion of the silica particles M, is H, the height H of the outer surface 20S is not constant in either the direction of the lamp axis E or the direction perpendicular to the lamp axis E, and the change is irregular and discontinuous. The inner surface 20M of the outer tube 20 does not contain silica particles and is composed of a flat surface.

[0029] FIG. 3 is a diagram showing the radiation direction of ultraviolet rays in the schematic cross-sectional view of FIG.

[0030] Most of the ultraviolet light emitted from the discharge space S travels along the radial direction of the lamp axis E and the lamp axial direction, passes through the outer tube 20, and is emitted from the outer surface 20S. At this time, the ultraviolet light emitted from the outer surface 20S1 travels while being reflected by the outer surface of the silica particles M, or passes through the silica particles M while being refracted. As a result, most of the ultraviolet light emitted in the radial direction from the outer surface 20S travels in a direction deviated from the radial direction of the outer tube 20. The same is true for the surface portion 20S2 of the outer surface 20S perpendicular to the lamp axis E.

[0031] In general, the intensity of ultraviolet light attenuates in proportion to the travel distance. For example, in the case of 172 nm ultraviolet light, the ultraviolet light reach distance at which the ultraviolet light intensity attenuates to 80% is relatively short (about a few mm). Therefore, the ultraviolet light reach distance that affects ozone generation is shortened by forming layered silica particles M on the outer surface 20S1. In other words, the ultraviolet light irradiation range that contributes to ozone generation is narrowed.

[0032] On the other hand, as described above, the silica particles M form an uneven surface layer with height ΔH that changes irregularly and randomly on the outer surface 20S of the outer tube 20. As a result, the ultraviolet irradiation range effective for ozone generation is generally uniform with respect to the lamp axis E of the outer tube 20 and the direction perpendicular to the lamp axis E. In Fig. 3, the ultraviolet irradiation range of the outer surface portion 20S1 along the lamp axis E is indicated by symbol R.

[0033] This makes it possible to generate high-concentration ozone around the excimer lamp 10. For example, when it is necessary to increase the lamp power and raise the ozone concentration for some reason, since the ultraviolet ray irradiation range R is relatively close to the outer surface 20S of the outer tube 20, it is possible to suppress the influence of ozone on the flow path tube 60 arranged around the excimer lamp 10 or on other components such as a power supply unit and support members (not shown).

[0034] Furthermore, since the outer surface 20S of the outer tube 20 is an uneven surface caused by the silica particles M, turbulence occurs in the raw material gas flowing along the outer surface 20S of the outer tube 20. In particular, since there are gaps between the silica particles M and the silica particles are configured with obtuse angles, the raw material gas easily flows between the silica particles, and therefore the flow of the raw material gas in the vicinity of the outer surface 20S becomes even more complicated (non-uniform).

[0035] This allows more source gas to flow around the excimer lamp 10, enabling more effective irradiation of ultraviolet light. Furthermore, because the silica particles have no sharp angles, sharp edges that may be damaged during lamp handling or the like do not become stuck between the silica particles and fill in the gaps, so the effect can be maintained stably for a long period of time.

[0036] Moreover, the silica particles M are fixed in a layer shape to the outer surface 20S, including both the surface portion 20S1 of the outer surface 20S1 along the lamp axis E and the surface portion 20S2 along the direction perpendicular to the lamp axis E. Therefore, the raw material gas can be irradiated with ultraviolet rays in the ultraviolet irradiation range R regardless of the flow direction of the raw material gas.

[0037] Here, the height H of the outer surface 20S, including the height h of the layered portion of the silica particles M and the thickness T of the outer tube 20, is desirably changed within 30% of the thickness T of the outer tube 20 with respect to the surface portion 20S1 along the lamp axis E. In other words, the height h of the layered portion of the silica particles M is set to 30% or less of the thickness T. By forming the layered portion of the silica particles M with such height adjustment, the ultraviolet light reach distance described above does not vary significantly depending on the location where the ultraviolet light passes through the outer tube 20. It is also desirably changed in height within 30% or less of the thickness T with respect to the surface portion 20S2 along the direction perpendicular to the lamp axis E.

[0038] Regarding ultraviolet rays (especially those with a wavelength of 200 nm or less), the transmittance of the silica glass affects the distance the rays pass through the silica glass, which tends to cause differences in the intensity of ultraviolet rays emitted from the silica glass. The layered portion of the silica particles M has a height change of 30% or less of the thickness T, which can prevent differences in the intensity of ultraviolet rays from occurring. Furthermore, the layered portion of the silica particles M does not have any steep portions that protrude locally from the outer surface 20S, and the height H can be considered to change smoothly overall. This prevents the intensity of ultraviolet rays emitted from the excimer lamp 10 from varying depending on the ultraviolet radiation location, and enables ultraviolet rays to be radiated so that the ultraviolet radiation distance along the lamp diameter direction is approximately uniform throughout the lamp, and the ultraviolet radiation range R is approximately uniform.

[0039] On the other hand, when the amount of change in height H, i.e., the height h of the layered portion of the silica particles M, exceeds a predetermined value (e.g., 0.3 mm or more), the layered portion of the silica particles M causes the raw material gas flowing around the excimer lamp 10 to be unnecessarily disturbed. As a result, the raw material gas leaves the ultraviolet ray irradiation range R before the amount of ultraviolet ray required for ozone generation is reached. The layered portion of the silica particles M can be formed so that the amount of change in height H is such that such a flow of raw material gas does not occur.

[0040] For example, in an excimer lamp that generates ozone by emitting 172 nm ultraviolet light, in which the thickness T of the outer tube 20 is 0.9 mm and the particle size of the silica particles M is 4 μm or less, the height h of the layered portion of the silica particles M is preferably 8 μm or more and 200 μm or less, and it is desirable that the silica particles have two or more layers (i.e., multiple layers). This makes it possible to reliably advance the ultraviolet light in a direction deviating from the radial direction while maintaining the ultraviolet light intensity even for 172 nm ultraviolet light, which has a rapid attenuation of ultraviolet light intensity, and to generate a suitable turbulence in the raw material gas on the outer surface 20S. Note that at least the height H described above may be adjusted for the surface portion 20S1 along the lamp axis E from which most of the ultraviolet light is emitted.

[0041] Such an excimer lamp 10 can be manufactured by the following manufacturing method.

[0042] First, a discharge tube that will become the outer tube with one open end and an inner tube that will be placed coaxially with the discharge tube are molded. An inner electrode is inserted into the inner tube and fused (or embedded) by heat treatment. Meanwhile, for the outer tube, crushed silica powder is attached to the outer surface of the arc tube that will become the outer tube to a predetermined thickness (here, 1 μm to 100 μm). At this time, the silica powder may be attached so as to achieve the amount of change in height H described above.

[0043] The outer tube is then heated to fix (fuse) the silica powder. At this time, the heat treatment removes any sharp edges in the silica particles. Thereafter, the inner tube is inserted into the outer tube by a conventional method, and the inner and outer tubes are fused together to seal in the discharge gas. Then, an outer electrode is placed on the outer surface of the discharge tube.

[0044] Particles other than silica particles that refract or reflect ultraviolet light when it passes through may be fixed (attached) to the outer surface of the outer tube in a layer or film form. In this case, the radiation direction of the ultraviolet light can be deflected from the radial direction.

[0045] Next, an excimer lamp according to a second embodiment will be described with reference to Fig. 4. In the second embodiment, the outer surface of the outer tube has an uneven shape.

[0046] 4 is a schematic partially enlarged cross-sectional view of the outer tube of the excimer lamp according to the second embodiment. The outer tube 20' of the excimer lamp 10 has an outer surface 20'S formed in a wavy shape. Here, the height H of the outer surface 20'S changes substantially regularly and continuously. The surface portion along the direction perpendicular to the lamp axis E is also formed in a wavy shape.

[0047] The outer surface 20'S has an uneven shape that is always inclined with respect to the lamp axis E, and the inclination of the inclined surface changes continuously. Therefore, the ultraviolet light that passes through the outer tube 20' is refracted when it leaves the outer surface 20'S, and travels in a direction deviated from the radial direction. This makes it possible to confine the ultraviolet light irradiation range R to the periphery of the excimer lamp 10, as in the first embodiment. In addition, since the outer surface 20'S has no sharp parts and forms a smoothly curved surface, it is possible to prevent ultraviolet light from concentrating on the sharp parts, which would deteriorate or damage the outer surface 20'S, and thus prevent localized generation of high-concentration ozone.

[0048] Here, if the height from the bottom to the top of the outer surface 20'S is h, the height from the inner surface 20'M of the outer pipe 20' to the top of the wavy portion is H, and the thickness from the inner surface 20'M of the outer pipe 20' to the bottom of the wavy portion is T, the height h of the outer surface 20'S varies within a range of 30% or less of the wall thickness T. In other words, the outer surface 20'S has an uneven shape in which the height h of the wavy portion is 30% or less of the wall thickness T, compared to the wall thickness T when the wavy portion is not formed.

[0049] Such an inner surface 20'M of the outer tube 20' can be formed by cutting with a laser processing machine or the like. The outer surface 20'S of the outer tube 20' may be formed with irregular wavy projections and recesses. Making the surface irregular can cause turbulence in the flow of the raw material gas, and ozone can be reliably generated regardless of the flow direction and speed of the raw material gas. Also, holes penetrating the ridges may be formed with a laser or the like (see dashed lines) to cause turbulence in the flow of the raw material gas.

[0050] FIG. 5 is a schematic, partially enlarged, cross-sectional view of the outer tube of an excimer lamp according to a third embodiment. The outer tube 20" of the excimer lamp 10 has a regular sawtooth shape here. Even with this uneven shape, ultraviolet light passing through the outer tube 20' is refracted when it emerges from the outer surface 20'S, and travels in a direction deviated from the radial direction. Also, as in the second embodiment, the unevenness of the outer surface 20'S may be formed so that the height h of the outer surface 20'S varies within a range of 30% or less of the wall thickness T.

[0051] It is also possible to form an uneven shape on the outer surface of the outer pipe other than those in the second and third embodiments. For example, the uneven shape may be formed by sandblasting.

[0052] The excimer lamp 10 is not limited to the arrangement in the flow path tube shown in the first to third embodiments, and can be applied to various ozone generators. In addition, the present invention can be applied to excimer lamps other than those having a double tube structure. [Explanation of symbols]

[0053] 10 Excimer Lamp 20 Outer tube 20S outer surface 30 inner tube 40 inner electrode 50 outer electrode M Silica Particles

Claims

1. a discharge tube forming a discharge space in which a discharge gas is sealed; an electrode for applying a voltage to the discharge space; The outer surface of the discharge tube is formed in a film or layer by adhering particles made of silica particles having a particle size in the range of 1 μm to 100 μm, An excimer lamp that can be used in an ozone generator, characterized in that ultraviolet light generated in the discharge space travels in a direction deviated from a radial direction when passing through the discharge tube.

2. 2. The excimer lamp according to claim 1, wherein the outer surface of the discharge tube is formed in a film or layer by adhering particles that deflect the direction of travel of ultraviolet rays.

3. 3. The excimer lamp according to claim 2, wherein the particles are fixed so that the height from the inner surface to the outer surface of the discharge tube varies irregularly at least along the axial direction of the tube.

4. 4. An excimer lamp usable in an ozone generator according to claim 2 or 3, wherein the height from the inner surface to the outer surface of said discharge tube varies by 30% or less of the wall thickness of said discharge tube.

5. 5. The excimer lamp usable in an ozone generator according to claim 2, wherein the particles are fixed to the entire outer surface of the discharge tube.

6. 2. The excimer lamp according to claim 1, wherein the outer surface of the discharge tube is formed of an uneven surface whose inclination changes regularly or irregularly along the tube axis direction.

7. A discharge tube forming a discharge space in which a discharge gas is sealed; an electrode for applying a voltage to the discharge space; The outer surface of the discharge tube is configured so that ultraviolet rays generated in the discharge space travel in a direction deviated from a radial direction when passing through the discharge tube, The outer surface of the discharge tube is formed of an uneven surface whose inclination changes regularly or irregularly along the tube axis direction, An excimer lamp that can be used in an ozone generator, wherein the uneven surface has a continuously changing inclination.

8. 8. An excimer lamp usable in an ozone generator according to claim 6 or 7, characterized in that the height from the inner surface to the outer surface of the discharge tube changes by 30% or less compared to the wall thickness when no irregularities are formed on the outer surface of the discharge tube.

9. a discharge tube made of silica glass and having a discharge space in which a discharge gas is sealed; an electrode for applying a voltage to the discharge space; An excimer lamp that can be used in an ozone generator, characterized in that a film or layer of silica particles having a particle size in the range of 1 μm to 100 μm and either uniform or non-uniform in particle size is fixedly formed on the entire outer surface of the discharge tube.

10. 10. An ozone generator comprising an excimer lamp that can be used in the ozone generator according to claim 1.

11. A powder made of crushed silica powder having a particle size in the range of 1 μm to 100 μm is applied to the entire outer surface of the discharge tube; The discharge tube is heat treated to adhere the silica powder.

1. A method for producing an excimer lamp that can be used in an ozone generator, comprising the steps of:

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