JP6573513B2 - Ultraviolet irradiation device and discharge lamp - Google Patents

Description

  The present invention relates to an ultraviolet irradiation device applied to an ozone water generation device and the like, and more particularly to an ozone water generation device including a double tube structure discharge lamp such as an excimer lamp.

  Ultraviolet irradiation devices are handled in various fields because ozone generated by ultraviolet rays is used for sterilization, deodorization, and cleaning means. As a method for generating ozone, a method of generating ozone by irradiating an oxygen-containing gas with ultraviolet rays is generally used. However, a method of irradiating water in which oxygen is dissolved with ultraviolet rays is also known (see Patent Document 1). ).

  There, high-concentration oxygen is dissolved in the water in the water tank to form a foam. And the ultraviolet light below 200 nm is irradiated to the bubble water of oxygen mixing with the light source arrange | positioned in the water tank. Oxygen absorbs ultraviolet rays to generate ozone, and transports ozone water to a sterilization system.

JP 2011-200778 A

  In such an ultraviolet irradiation apparatus that irradiates the liquid with ultraviolet rays, it is difficult to uniformly irradiate the entire liquid in the flow path with ultraviolet light simply by installing the discharge lamp that irradiates the ultraviolet light inside the flow path as it is. In addition, it is difficult to reduce the size of the apparatus by installing a discharge lamp inside the flow path, but it is necessary to take a waterproof measure for the wiring in the flow path, and the apparatus becomes complicated.

  Therefore, it is required to provide an ultraviolet irradiation apparatus that can easily reduce the size with a simple configuration and that effectively irradiates a liquid containing oxygen with ultraviolet rays to generate ozone.

  The ultraviolet irradiation apparatus of the present invention is an ultraviolet irradiation apparatus having a discharge lamp that emits ultraviolet light and a flow path through which a fluid (liquid) containing oxygen irradiated with ultraviolet light from the discharge lamp flows. The discharge lamp includes an outer tube, an inner tube, a discharge space formed between the outer tube and the inner tube, an inner electrode embedded in a tube wall of the outer tube, and an outer surface of the tube wall of the outer tube. It has an outer electrode disposed on the top and at least a portion facing the inner electrode across the discharge space. The inside of the inner tube communicates with the flow path, and the liquid fluid flows inside the inner pipe and the flow path. Further, a structure in which a liquid fluid circulates between the inside of the inner tube and the flow path may be used.

  The “fluid containing oxygen (liquid)” here includes a liquid in which oxygen is naturally dissolved, such as water, and a liquid in which oxygen is mixed and dissolved by bubbling or the like. A discharge lamp that emits ultraviolet rays by irradiating a liquid containing oxygen with ultraviolet rays, for example, is a lamp that emits ultraviolet rays having a wavelength of 172 nm. An excimer lamp that discharges by dielectric barrier discharge or capacitively coupled high-frequency discharge is used. Applicable. The discharge lamp that irradiates the fluid with ultraviolet rays and sterilizes the fluid can be a discharge lamp that emits ultraviolet rays including at least one wavelength of 185 nm, 207 nm, 222 nm, 253 nm, or 254 nm.

  In the present invention, the discharge lamp includes an inner electrode embedded in the tube wall of the outer tube, and an outer electrode that is installed on the outer surface of the outer tube and at least a part of the outer electrode facing the inner electrode across the discharge space. Have. As a result, it is possible to uniformly irradiate the liquid passing through the inner side of the inner tube without being biased by the ultraviolet irradiation by the dielectric barrier discharge.

  In view of facilitating handling of the electrodes, the inner electrode of the discharge lamp is an electrode to which a high voltage is applied, and the outer electrode is a ground electrode. The outer tube circumferential length of the outer electrode is larger than the outer tube circumferential length of the inner electrode. The outer electrode can be applied in various configurations. For example, the outer electrode can be configured as a single unit. In order not to make it difficult to break down the insulation between the inner electrode and the inner electrode, it is preferable that the outer tube circumferential length of the outer electrode is the entire length of the outer tube surface circumferential length.

  On the other hand, the outer electrode can be composed of a main electrode facing the inner electrode, and an auxiliary electrode having the same potential as the main electrode arranged away from the main electrode. In order to facilitate discharge, the distance interval along the outer tube circumferential direction between the auxiliary electrode and the inner electrode may be made substantially equal to the distance interval along the outer tube circumferential direction between the auxiliary electrode and the main electrode. A fluid supply unit that sends a fluid such as a pump to the inside of the inner tube of the discharge lamp through the flow path may be disposed upstream of the discharge lamp. In addition, an oxygen mixed fluid generating unit that dissolves oxygen in a liquid flowing through the channel by bubbling or the like may be provided on the upstream side of the channel.

  A discharge lamp in another aspect of the present invention is a discharge lamp having an outer tube and an inner tube, and emitting ultraviolet rays by discharge in a discharge space formed between the outer tube and the inner tube. An inner electrode embedded in the tube wall and an outer electrode disposed on the outer surface of the outer tube and at least partially facing the inner electrode across the discharge space, and contains oxygen inside the inner tube It is a discharge lamp that irradiates fluid with ultraviolet rays.

  According to the present invention, for example, in an ultraviolet irradiation device such as an ozone water generation device, ultraviolet light can be effectively irradiated to a fluid with a simple and miniaturizable configuration.

It is the figure which showed the internal structure of the ozone water generating apparatus which is 1st Embodiment. It is sectional drawing along the axis line of a discharge lamp. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is sectional drawing of the discharge lamp from which the structure of an outer side electrode differs from 1st Embodiment. It is sectional drawing of the discharge lamp provided with the auxiliary electrode.

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

  FIG. 1 is a diagram illustrating an internal configuration of an ultraviolet irradiation device (hereinafter referred to as an ozone water generation device) that generates ozone water according to the first embodiment.

  The ozone water generation device 10 is a device that generates ozone water by irradiating water, which is a fluid, with ultraviolet light. The inlet 10A is connected to a water supply line (not shown) and the outlet 10B is a sterilization treatment system (not shown). Etc. are connected. A pump 40, a power supply 50, and a discharge lamp 60 are provided in the ozone water generator 10.

  Further, in the ozone water generating apparatus 10, channel tubes 15A and 15B forming a channel of water are provided on the inlet side and the outlet side, respectively, and are connected to an inner tube 61 of a discharge lamp 60 described later. To do. The pump 40 flows out water from the inflow port 10A from the outflow port 10B via the flow channel pipe 15A, the inner tube 61, and the flow channel tube 15B that are in communication with each other. In addition, by providing the pump 40 in the flow pipes 15A and 15B or an external device connected to the inlet 10A and the outlet 10B, water can be introduced into the ozone water generator 10, but the ozone generated Considering the influence on the pump 40, the pump 40 is preferably arranged on the upstream side of the discharge lamp 60.

  An oxygen dissolving device 30 is provided in the flow channel 15A on the inlet 10A side from the discharge lamp 60 as necessary. Here, the oxygen dissolving device 30 can contain oxygen bubbled in water by bubbling treatment, or can dissolve (dissolve) oxygen in water. However, for example, oxygen is dissolved in general water such as tap water, and when supplying a liquid containing oxygen sufficiently to the inlet 10A in this way, without providing the oxygen dissolving device 30, The liquid may be configured to be irradiated with ultraviolet rays as it is. Further, an oxygen dissolving device 30 may be provided in an external device (not shown) connected to the inflow port 10A to dissolve oxygen in water. When water containing bubble-like oxygen or water in which oxygen is dissolved passes through the inner tube 61, ozone water is generated by ultraviolet rays irradiated from the discharge lamp 60. The ozone water flows out through the flow path pipe 15B.

  The power supply circuit 50 turns on the discharge lamp 60 and drives the pump 40. The discharge lamp 60 includes an inner electrode 64 and an outer electrode 66 that form a pair, and a voltage is applied to the inner electrode 64 and the outer electrode 66 through wirings 67A and 67B.

FIG. 2 is a cross-sectional view along the axis of the discharge lamp. 3 is a cross-sectional view taken along line III-III in FIG.

  The discharge lamp 60 is an excimer lamp having a double tube structure in which an inner tube 61 and an outer tube 62 made of a dielectric material such as quartz glass are integrally coaxially arranged, and an outer electrode is disposed on the outer surface of the outer tube 62. On the other hand, an inner electrode is embedded in the tube wall 62 </ b> W of the outer tube 62.

  The outer tube 62 of the discharge lamp 60 is integrally formed by welding a cylindrical quartz tube 62W2 and a cylindrical quartz tube 62W1 disposed on the inner side thereof. The tube 62 and the inner tube 61 are welded. Both end portions of the inner tube 61 protrude from the outer tube 62 along the axial direction.

  A hollow cylindrical (annular cross-section) discharge space DS is formed between the outer tube 62 and the inner tube 61. The discharge space DS is filled with a rare gas or a mixed gas of a rare gas and a halogen gas as a discharge gas. For example, the rare gas is Xe gas, Ar gas, or Kr gas, and the mixed gas of rare gas and halogen gas is ArBr gas, ArF gas, KrCl gas, XeI gas, XeCl gas, XeBr gas, or KrBr gas. Etc. are enclosed. The inner surface of the inner electrode 64 has ultraviolet reflection characteristics. The inner surface of the outer electrode 66 has ultraviolet reflection characteristics.

  As shown in FIG. 3, the outer electrode 66 is configured by a film or foil-shaped electrode that covers the entire outer surface of the outer tube 62 in the circumferential direction. A power supply line 67 </ b> B is connected to the end of the outer electrode 66. The axial length of the outer electrode 66 is determined to be shorter by E at both ends than the axial length of the outer tube 62.

  The inner electrode 64 is configured by a fan-shaped film or a foil-shaped electrode, and is embedded in the vicinity of the center along the radial direction of the outer tube 62 and is not exposed to the discharge space DS. The axial length of the inner electrode 64 is shorter than the axial length of the outer electrode 66, and the end thereof is connected to the power supply line 67A.

  The circumferential length of the inner electrode 64 embedded in the tube wall 62 </ b> W of the outer tube 62 is sufficiently shorter than the circumferential length of the outer tube 62. Here, the fan angle with respect to the central axis X is set within 30 degrees. Accordingly, the inner electrode 64 faces a part of the outer electrode 66 with the discharge space DS formed around the inner tube 61 forming the flow path F interposed therebetween.

  For example, the inner diameter of the inner tube 61 is 0.5 mm to 3 mm, the axial length of the discharge space DS is 20 mm to 200 mm, and the radial length (thickness) of the discharge space DS is 5 mm to 17 mm. Determined.

  The power supply unit 50 is a high-frequency AC power supply device, the outer electrode 66 is a ground electrode, and the inner electrode 64 is an electrode to which a high voltage is applied. When a voltage is applied, a dielectric barrier discharge first occurs between the discharge distances indicated by the broken line AD1 in FIG. 3, and then discharges are sequentially generated in the order of the broken lines AD2 and AD3. As a result, excimer light, that is, ultraviolet light (ultraviolet light) is emitted. The wavelength of the ultraviolet light varies depending on the type of discharge gas sealed in the discharge space DS. For example, the discharge gas is 172 nm for Xe gas, 126 nm for Ar gas, 146 nm for Kr gas, 165 nm for ArBr gas, 193 nm for ArF gas, 222 nm for KrCl gas, 253 nm for XeI gas, 308 nm for XeCl gas, 283 nm for XeBr gas, In KrBr gas, ultraviolet rays having a wavelength of 207 nm are emitted.

  Here, when the end portion of the glass tube 62W1 constituting the outer tube 62 protrudes by the axial distance E, the outer electrode 66 and the feeding line 67A are sufficiently insulated, and the feeding line 67A and the outer electrode 66 are separated from each other. Creeping discharge is prevented. Similarly, the end portion of the glass tube 62W2 constituting the outer tube 62 protrudes along the axial direction from the reduced diameter starting portion 62J of the glass tube 62W1, thereby allowing the outer electrode to pass through the lead portion of the feeder line 67A. 66 and the inner electrode 64 are prevented from creeping discharge.

  When the inner electrode 64 and a part of the outer electrode 66 face each other across the discharge space DS, a dielectric barrier discharge is generated so as to cover the inner tube 61 in which the flow path F is formed (see broken line AD3). As a result, the entire inner tube 61 is irradiated with ultraviolet rays, and the ultraviolet rays are uniformly irradiated to the water flowing through the internal flow path F. Further, since the inner surface of the outer tube 62 and the inner surface of the inner tube 61 have ultraviolet reflection characteristics, the ultraviolet rays do not leak to the outside of the discharge lamp 60 (particularly, the outside in the lamp radial direction).

As described above, when ultraviolet light having a wavelength of 172 nm is irradiated to water containing bubble-like oxygen or water in which oxygen is dissolved, ozone (O ₃ ) is generated by an oxidizing action, and ozone water is Generated. As shown in the following formulas (1) and (2), ultraviolet rays having a wavelength of 172 nm decompose oxygen to produce active oxygen, and active oxygen (oxygen atoms) combines with oxygen (oxygen molecules) to generate ozone. Is generated.

O ₂ + UV → 2O (1)
O + O ₂ → O ₃ (2)

The ozone water thus generated is sent from the downstream outlet 10B to an external sterilization system. Furthermore, water can be suitably sterilized by irradiating water with ultraviolet rays containing at least one wavelength of 185 nm, 207 nm, 222 nm, 253 nm, or 254 nm. This is because ultraviolet rays including wavelengths such as 185 nm, 207 nm, 222 nm, 253 nm, and 254 nm have the ability to cleave molecular bonds constituting the DNA of organisms, and kill bacteria by destroying the DNA.

  As described above, according to the present embodiment, the ozone water generation apparatus 10 includes the discharge lamp 60 that is an excimer lamp having a double tube structure, and the discharge lamp 60 includes the inner tube 61 connected to the flow channel tubes 15A and 15B. An outer tube 62. The inner tube 61 is not provided with an electrode, the inner electrode 64 is embedded in the tube wall 62W of the outer tube 62, and the outer electrode 66 is disposed on the outer surface 62S of the outer tube 62. The outer electrode 66 has a circumferential length that covers the entire circumferential direction of the outer tube 62, while the inner electrode 64 faces a part of the outer electrode 66 across the discharge space DS surrounding the inner tube 61. It has such a circumferential length.

  The ozone concentration may be controlled by stopping the operation of the pump 40 at predetermined time intervals. For example, the flow rate of water in which oxygen is dissolved can be set in the range of 10 L / min to 200 L / min when the inner diameter of the inner tube is 0.5 mm to 3 mm.

  By connecting the inner tube of the discharge lamp and the channel tube through which water flows, the ozone water generating device 10 can be downsized. Further, it is not necessary to perform waterproofing on the electrodes and wiring portions of the discharge lamp, and a simpler configuration can be adopted.

  Since the structure of the discharge lamp is such that no electrode is provided on the inner tube, the water flowing through the flow path can be irradiated with ultraviolet rays from the entire circumference. In particular, since the outer electrode is a ring-shaped electrode that extends in the entire outer circumferential direction of the outer tube, discharge is started with a low starting voltage, and stable startability can be obtained in dielectric barrier discharge. And discharge generate | occur | produces in the radial direction substantially whole region of the discharge space DS (refer broken line AD1-AD3), and it suppresses that a spot arises in discharge.

  Further, since the outer electrode 66 is a ground electrode and the inner electrode 64 is an electrode to which a high voltage is applied, it is not necessary to perform an insulation process around the discharge lamp including the inner surface of the inner tube through which water flows.

  By the way, a discharge lamp other than the electrode configuration described above is possible. Hereinafter, other structures of the discharge lamp will be described.

  FIG. 4 is a cross-sectional view of a discharge lamp 60 'in which the configuration of the outer electrode is different from that of the first embodiment. FIG. 5 is a cross-sectional view of a discharge lamp 60 ″ having an auxiliary electrode.

  In FIG. 4, the outer electrode 66 ′ is configured in the same size as the inner electrode 64. The circumferential length of the outer electrode 66 ′ is substantially equal to the circumferential length of the inner electrode 64. The outer electrode 66 ′ is disposed so as to face the inner electrode 64 with the inner tube 61 interposed therebetween. Even with such an electrode structure, dielectric barrier discharge is generated in a range including the inner tube 61.

  In FIG. 5, in addition to the outer electrode 66 ′ of FIG. 4, an auxiliary outer electrode 67 is provided on the outer surface 62 </ b> S of the outer tube 62. The size of the auxiliary outer electrode 67 and the length in the outer tube circumferential direction are substantially the same as those of the outer electrode 66 '. Further, the distance interval along the outer tube circumferential direction between the outer electrode 66 ′ and the auxiliary outer electrode 67 is the distance interval along the outer tube circumferential direction between the auxiliary outer electrode 67 and the inner electrode 64. Almost equal. Even with such an electrode structure, the starting voltage can be lowered.

  As described above, the outer electrode can be adjusted by itself in the circumferential length, or by adjusting the position of the auxiliary outer electrode while arranging a plurality of outer electrodes, so that the ultraviolet rays can be transferred to the flow path in the inner tube. It is possible to irradiate uniformly and to discharge stably. In the case of a single outer electrode, the circumferential length of the electrode is preferably a semicircular electrode cross-sectional shape, that is, a fan-shaped electrode shape that draws an arc of 180 degrees or more.

  In this embodiment, an excimer lamp that irradiates excimer light (ultraviolet rays) by dielectric barrier discharge is applied as a discharge lamp. However, a discharge lamp that irradiates ultraviolet light by high frequency discharge or capacitive discharge is also applied. Is possible.

10 Ozone water generator (ozone generator)
30 Oxygen dissolving device 40 Pump (liquid supply part)
60 Discharge lamp 61 Inner tube 62 Outer tube 64 Inner electrode 66 Outer electrode

Claims (10)

In an ultraviolet irradiation device having a discharge lamp that radiates ultraviolet rays, and a flow channel tube through which a fluid containing oxygen that is irradiated with ultraviolet rays by the discharge lamp flows,
The discharge lamp is
An inner tube having both ends connected to the flow channel tube;
An outer side tube which is coaxially arranged with said inner tube,
A discharge space formed between the outer tube and the inner tube;
An inner electrode embedded in the tube wall of the outer tube;
An outer electrode disposed on an outer surface of a tube wall of the outer tube, and at least a part of the outer electrode facing the inner electrode across the discharge space;
The ultraviolet irradiation device, wherein the entire inside of the inner tube is a flow path through which the fluid flows . The ultraviolet irradiation device according to claim 1, wherein the fluid circulates between the inner tube and the flow channel tube .   3. The ultraviolet irradiation device according to claim 1, wherein the discharge lamp emits ultraviolet light including a wavelength of 172 nm.   The ultraviolet irradiation device according to claim 1, wherein ozone is generated by the discharge lamp emitting ultraviolet light to the fluid.   5. The ultraviolet irradiation device according to claim 1, wherein the discharge lamp emits ultraviolet light including at least one wavelength of 185 nm, 207 nm, 222 nm, 253 nm, or 254 nm. The outer electrode is a ground electrode;
6. The ultraviolet irradiation apparatus according to claim 1, wherein the inner electrode is an electrode to which a high voltage is applied. The outer electrode is composed of an integral conductive member,
The ultraviolet irradiation apparatus according to any one of claims 1 to 6, wherein a length of the outer electrode in the outer tube circumferential direction is equal to or greater than a length of the inner electrode in the outer tube circumferential direction. The outer electrode is
A main electrode opposed in the radial direction across the inner electrode and the discharge space;
The ultraviolet irradiation device according to claim 1, further comprising: an auxiliary electrode having the same potential as the main electrode and spaced apart from the main electrode in the circumferential direction. The ultraviolet irradiation apparatus according to claim 1, wherein a fluid supply unit that sends the fluid to the inner tube through the flow channel tube is disposed upstream of the discharge lamp. Ultraviolet rays are emitted by discharge in a discharge space formed between a flow path tube through which a fluid containing oxygen flows, an inner tube connected at both ends, an outer tube coaxially arranged with the inner tube, and the outer tube and the inner tube. A radiating discharge lamp,
An inner electrode embedded in a tube wall of the outer tube, and an outer electrode disposed on the outer surface of the outer tube, and at least a part of the outer electrode facing the inner electrode across the discharge space,
The discharge lamp according to claim 1 , wherein the inside of the inner tube is a flow path through which the fluid flows .

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