Excimer lamp, and ozone generation method using excimer lamp

Abstract

To provide an excimer lamp capable of generating ozone at a desired ozone concentration with a simple structure.SOLUTION: An excimer lamp 10 is disposed in a flow channel pipe 60 where a material gas flows from an inlet 60A to an outlet 60B. The excimer lamp 10 includes a tubular discharge pipe (discharge container) 20 formed of a dielectric material such as quartz glass, and has an outer electrode 40 disposed on an outer surface 20S of the discharge pipe 20. The outer electrode 40 is formed of titanium.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an excimer lamp capable of generating ozone. [Background technology]

[0002] In an excimer lamp, a discharge gas is sealed inside a discharge tube, and an electrode (inner electrode) is provided inside the discharge tube and an electrode (outer electrode) is provided on the outer surface of the discharge tube. Excimer light (ultraviolet rays) is emitted by applying a high-frequency voltage between the electrodes.

[0003] For example, when an excimer lamp is applied to an ozone generator, the excimer lamp is placed in a flow tube (see Patent Document 1). In this case, while a raw material gas containing oxygen flows through the flow tube, ozone is generated by emitting ultraviolet light having a peak wavelength (e.g., 172 nm) in the wavelength range capable of generating ozone. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-198145 Summary of the Invention [Problem to be solved by the invention]

[0005] Ozone generators using excimer lamps are used in a variety of environments, including industrial applications in factories, etc. In addition to being designed and installed in advance to suit the industrial product in which they are incorporated, some ozone generators are modularized and can be detachably attached as ultraviolet irradiation devices and incorporated into the device as needed.

[0006] The temperature of the object or fluid to be irradiated with ultraviolet light depends on the processing configuration of the device, and the temperature of the discharge tube of the excimer lamp is also affected by the ambient temperature. Such temperature changes in the discharge tube of the excimer lamp may lead to a decrease in ultraviolet light irradiance, making it impossible to generate ozone at the desired concentration.

[0007] On the other hand, temperature control of the discharge tube of an excimer lamp requires precise temperature measurement using a sensor and temperature and flow rate adjustment of the source gas to be irradiated with ultraviolet light. However, such temperature control of the discharge tube leads to the complication of the device. Furthermore, when the excimer lamp is incorporated into the device using a modular configuration, temperature control of the discharge tube is difficult.

[0008] Therefore, it is desired to provide an excimer lamp that can generate ozone at a desired ozone concentration with a simple configuration. [Means for solving the problem]

[0009] An excimer lamp according to one aspect of the present invention comprises a discharge vessel capable of emitting ultraviolet rays that generate ozone in an oxygen-containing fluid, and electrodes provided on the outer surface of the discharge vessel. The electrodes are made of aluminum, titanium, tantalum, or tungsten. With this electrode configuration, the lamp can be lit even when the temperature of the outer surface of the discharge vessel reaches 80°C or higher. Here, "being able to ignite the lamp" means that the lamp can continue to be lit without any substantial change in the ozone generation state, such as the ozone concentration, compared to temperatures below 80°C.

[0010] The electrodes may be arranged in various configurations, for example, the electrodes may be made of titanium wire or titanium plate that is tightly wrapped around the outer surface of the discharge vessel.

[0011] There are also various configurations for disposing the discharge vessel. For example, the discharge vessel can be arranged coaxially within a flow path pipe through which a fluid flows from an inlet to an outlet, and the distance between the outer surface of the discharge vessel and the inner surface of the flow path pipe can be configured so that it is equal to or less than the transmission distance at which the intensity ratio of ultraviolet light emitted from the outer surface of the discharge vessel is attenuated to 20%.

[0012] Another aspect of the present invention is an ozone generation method in which a discharge gas that emits ultraviolet light having a wavelength that generates ozone in an oxygen-containing fluid is sealed in a discharge vessel, electrodes made of aluminum, titanium, tantalum, or tungsten are provided on the outer surface of the discharge vessel, and the lamp is turned on.

[0013] For example, the discharge vessel can be placed inside the housing of the processing device so that the lamp lights up in an airtight state. Also, the discharge vessel can be placed coaxially with a flow tube through which a fluid flows from an inlet to an outlet, with the distance between the outer surface of the discharge vessel and the inner surface of the flow tube falling within the range of 1 mm to 10 mm, and the flow rate of the fluid flowing through the flow tube can be set to 3 L / min or less. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an excimer lamp that can generate ozone at a desired ozone concentration with a simple configuration. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view of an excimer lamp according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] The excimer lamp of this embodiment will be described below with reference to the drawings.

[0017] Fig. 1 is a schematic cross-sectional view of an excimer lamp taken along the electrode width direction, and Fig. 2 is a schematic cross-sectional view taken along line II-II in Fig. 1.

[0018] The excimer lamp 10 is capable of generating ozone by irradiating a raw material gas containing oxygen with ultraviolet rays, and is installed in an ozone generator 100 having a housing 60 here.

[0019] The excimer lamp 10 generates ozone during operation of the ozone generator 100, and supplies the ozone to the outside of the ozone generator by operating an axial fan, centrifugal fan, or the like (not shown).

[0020] The excimer lamp 10 is disposed within a flow path pipe 60 through which source gas flows from an inlet 60A to an outlet 60B. The flow path pipe 60 is a cylindrical flow path pipe with a circular cross section, and the excimer lamp 10 is disposed coaxially within the flow path pipe 60. In other words, the excimer lamp 10 is housed within the flow path pipe 60 so that the lamp axis C of the excimer lamp 10 is aligned with the axis of the flow path pipe 60, and is held by a holding member (not shown).

[0021] The excimer lamp 10 includes a tubular discharge tube (discharge vessel) 20 made of a dielectric material such as quartz glass, and is configured here as a discharge tube with a circular cross section along the tube diameter (lamp diameter) direction. A rare gas such as xenon gas or a mixture of these gases is sealed in the discharge space S within the discharge tube 20 as a discharge gas.

[0022] A foil electrode 30 is disposed inside the discharge tube 20, extending in a strip shape along the tube axis (lamp axis) C. The foil electrode 30 is covered by a columnar dielectric 50 made of quartz glass or the like, and is buried within the dielectric 50 without being exposed to the discharge space S. In other words, the foil electrode 30 is sealed (adhered) to the dielectric 50. A power supply line (power supply rod) 70 is connected to the end of the foil electrode 30 along the lamp axis C, and is also connected to an externally installed power supply unit (not shown).

[0023] The foil electrode 30 is arranged coaxially with its center position in the width direction and thickness direction aligned with the center position of the dielectric 50. Furthermore, the dielectric 50 is arranged coaxially with the discharge tube 20. Therefore, the foil electrode 30 is arranged coaxially with the discharge tube 20 and symmetrically with respect to the lamp axis C. In FIG. 2, the width direction of the foil electrode 30 is defined as the Y direction, and the direction perpendicular thereto (thickness direction) is defined as the X direction.

[0024] The outer electrode 40 arranged on the outer surface 20S of the discharge tube 20 is configured by winding a conductive wire made of a conductive metal along the outer surface of the discharge tube 20, and is wound spirally along the lamp axis C and arranged at predetermined intervals.

[0025] The outer electrode 40 is provided with such a spiral electrode portion (hereinafter referred to as the spiral portion 42) as well as conductive members (hereinafter referred to as the cylindrical members) 45A, 45B that contact both ends of the spiral portion 42. Here, the cylindrical members 45A, 45B are configured by wrapping a strip-shaped conductive plate around the lamp axis C in a cylindrical shape to cover part of the outer surface 20S of the discharge tube 20.

[0026] 2, the foil electrode 30 has a substantially constant cross-sectional shape along the lamp axis C, and has a knife-edge shape that tapers from a flat portion of constant thickness toward both ends in the width direction. On the other hand, the dielectric 50 has a flat external shape.

[0027] Here, the excimer lamp 10 is configured as a small excimer lamp. For example, the axial length (light-emitting length) in which discharge occurs inside the discharge tube 20 can be set in the range of 20 mm to 400 mm. The outer diameter of the discharge tube 20 can be set in the range of 5 mm to 30 mm, preferably in the range of 8 mm to 25 mm.

[0028] The thickness of the discharge tube 20 can be set in the range of, for example, 0.8 mm to 1.5 mm, taking into consideration prevention of discharge tube deterioration due to excimer light and suppression of an increase in discharge start voltage.

[0029] The foil electrode 30 and the outer electrode 40 have polarities set to anode and cathode, respectively. High frequency (for example, in the range of several kHz to several tens of MHz) and high voltage (for example, in the range of several kV to several tens of kV) are supplied to the excimer lamp 10 via a power supply line 70. The application of the high frequency voltage causes a discharge, which radiates ultraviolet light (for example, ultraviolet light with a wavelength of 172 nm) that is excimer light.

[0030] As described above, while the source gas containing oxygen flows through the flow path pipe 60, ozone is generated by the ultraviolet rays emitted from the excimer lamp 60, and the gas containing ozone flows out from the outlet 60B of the flow path pipe 60. The distance D between the inner surface 60S of the flow path pipe 60 and the outer surface 20S of the discharge tube 20 is determined so that the source gas flowing through the flow path pipe 60 is effectively irradiated with ultraviolet rays.

[0031] Here, the distance D between the outer surface 20S of the discharge tube 20 and the inner surface 60S of the flow path tube 60 is determined so as 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 20S of the discharge tube is attenuated to 20%.

[0032] For example, when irradiating ultraviolet light with a wavelength of 172 nm, the transmission distance of which attenuation reaches 20% is several mm, the flow path tube 60 that houses the discharge tube 20 is set to a size (radial length) such that the distance D from the discharge tube 20 is relatively short.

[0033] Due to this arrangement of the flow path tube 60 and the excimer lamp 10, the temperature of the outer surface 20S of the discharge tube 20 is likely to reach a high temperature during lamp operation. In particular, because the excimer lamp 10 is arranged in a casing 100K so as to operate at a low flow rate, the outer surface 20S of the discharge tube 20 is likely to reach a high temperature. As a result, the lamp will continue to operate in an environment where the temperature of the outer surface 20S of the discharge tube 20 exceeds 80°C, rather than in a normal (standard) operating environment where the lamp is operated so that the temperature of the outer surface 20S of the discharge tube 20 is lower than 80°C.

[0034] In this embodiment, the outer electrode 40 is made of titanium. Specifically, a titanium wire is wound around the outer surface 20S of the discharge tube 20 so as to be in close contact with the outer surface 20S.

[0035] Titanium, which constitutes the outer electrode 40, does not function as a catalyst for decomposing ozone at high temperatures, particularly at temperatures above 80° C. Furthermore, when the excimer lamp 10 is turned on at a temperature above 80° C. on the outer surface 20S of the discharge tube 20, ultraviolet radiation is usually reduced, which affects ozone generation.

[0036] However, by forming the outer electrode 40 from titanium, it is possible to generate ozone at a desired ozone concentration even in an environment where the outer surface 20S of the discharge tube 20 exceeds 80° C. This is presumably because, since the outer electrode 40, which is made of titanium, is wound around the outer surface 20S of the discharge tube 20 so as to be in close contact with it, even if the inner surface of the outer electrode 40, which is in close contact with the outer surface 20S of the discharge tube 20, is irradiated with ultraviolet light and its catalytic function is activated, little ozone comes into contact with the inner surface of the outer electrode 40, and therefore ozone decomposition is not promoted.

[0037] Therefore, by using titanium as the outer electrode 40, the lamp can be lit at a temperature lower than the normal ambient temperature of the outer surface 20S of the discharge tube 20, i.e., 80°C, and even if the lamp is lit at a temperature of 80°C or higher, ozone can be generated at a desired ozone concentration.

[0038] In particular, ozone can be generated effectively even in an operating environment where the flow rate of the raw material gas flowing through the flow path pipe 60 is low and the distance D between the outer surface 20S of the discharge tube 20 and the flow path pipe 60 is relatively short. For example, ozone can be generated effectively even in an operating situation where the distance D is set in the range of 1 mm to 10 mm and an axial flow fan or the like is operated so that the flow rate of the raw material gas is 3 L / min or less.

[0039] The housing 60 in which the excimer lamp 10 is disposed may be configured as an airtight container in which the source gas is not flowed and the inside of the housing 60 is maintained in an airtight state. That is, the housing 60 may be configured so that the inlet 60A and the outlet 60B are closed and the internal space within the housing 60 and the external space outside the housing 60 are not spatially connected.

[0040] In this case, the housing 60 functions as a jacket tube that houses the excimer lamp 10, and allows ultraviolet rays emitted from the excimer lamp 10 to pass through, irradiating the irradiated fluid, such as the raw material gas, flowing around the housing 60 with ultraviolet rays, thereby generating ozone.

[0041] The outer electrode 40 may be made of a titanium plate instead of a titanium wire. Furthermore, the outer electrode 40 is not limited to a spirally wound configuration, and may be made of a titanium wire or titanium plate that is in close contact with the outer surface 20 of the discharge tube 20, and ozone can be generated effectively even at high temperatures.

[0042] The outer electrode 40 may be made of a metal other than titanium, such as tantalum or tungsten, or may be made of aluminum.

[0043] It is possible to configure the inner electrode as an electrode other than the foil electrode 30. Furthermore, the discharge tube 20 may be used as a dielectric, and an electrode may be provided on the outer surface of the discharge tube 20 to apply a voltage.

[0044] When an excimer lamp having an outer electrode made of titanium wound around its outer surface according to the above embodiment was installed in an ozone generator and the lamp was turned on, it was confirmed that there was substantially no effect on ozone generation even when the lamp was turned on at temperatures above 80°C. [Explanation of symbols]

[0045] 10 Excimer Lamp 20 Discharge tube (discharge vessel) 30 foil electrode 40 Outer electrode (electrode) 50 Dielectric 60 Flow pipe 100 Ozone Generator

Claims

1. a discharge vessel capable of emitting ultraviolet light to generate ozone in an oxygen-containing fluid; an electrode provided on the outer surface side of the discharge vessel, The electrode is made of aluminum, titanium, tantalum, or tungsten, An excimer lamp capable of lighting when the temperature of the outer surface of the discharge vessel is 80°C or higher.

2. The electrode is made of a titanium wire or a titanium plate, 2. The excimer lamp according to claim 1, wherein the discharge tube is tightly wrapped around the outer surface of the discharge vessel.

3. the discharge vessel is coaxially disposed within a flow pipe through which the fluid flows from an inlet to an outlet; 2. The excimer lamp according to claim 1, wherein the distance between the outer surface of the discharge vessel and the inner surface of the flow path tube is equal to or less than the transmission distance at which the ultraviolet intensity ratio of the ultraviolet light radiated from the outer surface of the discharge vessel is attenuated to 20%.

4. a discharge gas that emits ultraviolet light having a wavelength that generates ozone in an oxygen-containing fluid is sealed in a discharge vessel; an electrode made of aluminum, titanium, tantalum or tungsten is provided on the outer surface of the discharge vessel; An ozone generating method using an excimer lamp, characterized by lighting the lamp.

5. 5. The ozone generating method using an excimer lamp according to claim 4, wherein the discharge vessel is disposed in a housing of a processing device so that the lamp lights up in an airtight state.

6. the discharge vessel is arranged coaxially with a flow path pipe through which the fluid flows from an inlet to an outlet, the distance between the outer surface of the discharge vessel and the inner surface of the flow path pipe being within a range of 1 mm to 10 mm; 5. The ozone generating method using an excimer lamp according to claim 4, wherein the flow rate of the fluid flowing through the flow pipe is set to 3 L / min or less.

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