JP3580775B2 - UV generator - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sterilization apparatus using a gas discharge device such as an ultraviolet lamp that generates ultraviolet light by electrodeless discharge using a discharge gas to which a halogen gas, mercury, or the like is added as a main component of a rare gas. It targets sterilization, disinfection, decolorization, deodorization and decolorization of industrial water, bleaching of pulp, and sterilization of medical equipment.
[0002]
[Prior art]
Ultraviolet light has been used for the purpose of sterilizing, disinfecting, and decolorizing water and sewage. As a light source that generates ultraviolet light, there are a mercury lamp, an excimer lamp, and the like. Low pressure mercury lamps generate ultraviolet light with a wavelength of 254 nm or 185 nm. Excimer lamps using xenon, krypton, and argon as excitation media generate ultraviolet light having wavelengths of 172 nm, 146 nm, and 126 nm, respectively.
[0003]
[Problems to be solved by the invention]
Conventional sterilizers and the like that generate ultraviolet light often use a low-pressure mercury lamp (a wavelength of mercury of 254 nm). The reason is that it is suitable for cutting bacterial DNA.
[0004]
Conventional mercury lamps include an electrode lamp in which an electrode is in contact with a discharge gas and an electrodeless lamp in which an electrode is not in contact with a discharge gas. Electrode lamps have a problem in that the life of the lamp is shortened due to deterioration of the discharge gas, wear of the electrodes, or adhesion of the worn electrode parts to the inner wall of the lamp. This is the upper limit.
[0005]
On the other hand, the electrodeless lamp has a problem that the utilization efficiency of ultraviolet light is low because the external electrode does not transmit ultraviolet light. Further, when an AC voltage (high frequency of 100 kHz or more) is applied to the external electrode to turn on the lamp, if the installation accuracy of the external electrode is low, the lamp may not be turned on properly due to a different discharge impedance.
[0006]
Further, in the electrodeless lamp, since the electrodes are outside, the wiring may be short-circuited due to a wiring error, water leakage, or the like, an inrush current may flow, and the power supply may be destroyed.
[0007]
In addition, when an electroded lamp or an electrodeless lamp is turned on using an AC power supply having a frequency of 100 kHz or more, if the electric wire connecting the power supply and the lamp is longer than a certain length, the lamp may not operate normally due to impedance mismatch. There is a risk of not lighting. In particular, if there is a large difference between the AC frequency of the power supply and the resonance frequency of the discharge unit, power cannot be used effectively due to the relationship between the output impedance of the power supply and the discharge impedance.
[0008]
Further, in an ultraviolet lamp which is turned on by passing an alternating current, when the power supply amount is increased, the voltage applied to the electric wire is increased, and the electric wire must be thickened in order to increase the withstand voltage. For this reason, it is difficult to route the electric wires, and the lamp may not be freely moved.
[0009]
The present invention has been made in view of such a point, and an object of the present invention is to provide an ultraviolet ray generator having low power consumption and high luminous efficiency.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention includes an electrode disposed around a dielectric container that can transmit ultraviolet light, and a power supply that applies an AC voltage or a pulse voltage to the electrode, and includes: In an ultraviolet ray generating device that emits ultraviolet light by causing a discharge inside the dielectric container by applying an AC voltage or a pulse voltage, the dielectric container is a hollow cylinder filled with a discharge gas. The electrode is a coil electrode wound on the outer peripheral surface of the cylindrical container, and includes a capacitor, a coil, and a power supply connected in series between one end of the coil electrode and a ground terminal.
[0011]
Since a plurality of electrodes are arranged outside the dielectric container to emit ultraviolet light from the dielectric container, the bulb does not break.
[0012]
It is desirable that the plurality of electrodes be arranged so as to have an aperture ratio of 70% or more.
[0013]
If at least a part of the surface of the electrode facing the dielectric container is formed of a material that reflects ultraviolet light or is processed into a shape capable of reflecting ultraviolet light, the luminous efficiency of ultraviolet light can be increased.
[0014]
By forming electrodes by baking a metal on the surface of the dielectric container, or by printing the electrodes on the surface of the dielectric container, it is possible to increase the installation position accuracy of the electrodes, and to suppress variations in discharge impedance due to manufacturing. .
[0015]
A coil electrode is wound around the outer peripheral surface of the dielectric container, and a capacitor, a coil, and a power supply are connected in series between one end of the coil electrode and the ground terminal. Inrush current can be prevented by the capacitor.
[0016]
One wire is connected to the power supply at one end of the cylindrical container, and the other wire is connected to the ground terminal at the other end of the cylindrical container, so that a voltage can be applied uniformly to the cylindrical container and the brightness of ultraviolet light can be increased. Can be suppressed.
[0017]
As AC frequency _{f OSC} of the power source and the resonant frequency _{f Z} of the discharge portion of the dielectric container satisfies the relation of _{1.1f OSC> f Z> 0.9f OSC} , by adjusting the AC frequency _{f OSC} of the power supply Thus, signal reflection hardly occurs, and the luminous efficiency of ultraviolet light can be improved.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an ultraviolet generating device according to the present invention will be specifically described with reference to the drawings.
[0019]
FIG. 1 is a diagram showing a schematic configuration of a first embodiment of an electrodeless discharge lamp which is an ultraviolet ray generator according to the present invention. The electrodeless discharge lamp 10 shown in FIG. 1 includes a dielectric container 1 made of a dielectric material having a hollow inside and transmitting ultraviolet light, a plurality of electrodes 2 disposed outside the container 1, and an AC voltage applied to each electrode 2. An AC power supply 3 to be applied and an electric wire 4 connecting the AC power supply 3 and the electrode 2 are provided.
[0020]
When an AC voltage is applied to the electrode 2 via the electric wire 4, a discharge occurs inside the dielectric container 1 and ultraviolet light is generated. This ultraviolet light is emitted to the outside through the space between the adjacent electrodes 2.
[0021]
The size of the electrode 2 is set so that the aperture ratio is 70% or more in order to increase the utilization efficiency of ultraviolet light. Further, at least a part of the surface of the electrode 2 on the side opposed to the dielectric container 1 is mirror-finished with a material that reflects ultraviolet rays. By such mirror finishing, the luminous efficiency of ultraviolet light can be further increased.
[0022]
In FIG. 1, the dielectric container 1 and the electrode 2 are separate members, but the electrode 2 may be formed by printing or printing a metal on the surface of the dielectric container 1. Thereby, the mounting accuracy of the electrode 2 is improved, and variation in the brightness of the ultraviolet light due to manufacturing can be suppressed.
[0023]
The effective length of the electric wire 4 is set to be equal to or less than 1/8 wavelength of the power supply frequency. The number N of the electric wires 4 is set so as to satisfy the condition (1), where P is the supplied power and Z is the characteristic impedance of the electric wires 4.
[0024]
[Equation 1]
300> √ (PZ / N) (1)
Hereinafter, the reason why the condition of the expression (1) is obtained will be described. FIG. 2 is a diagram illustrating the relationship between the frequency (MHz), the attenuation (dB / km), and the power capacity (W) of the high-frequency coaxial cable. Since the electrodeless discharge lamp 10 used for sewage treatment requires a withstand voltage of about 1000 V, a high-frequency coaxial cable that can be used at a power supply frequency of 15 MHz with a power capacity of 3000 W with a margin of three times that. 2 in FIG. 2 shows that a high-frequency coaxial cable called 8D-2V is applicable.
[0025]
Although the electric wire 4 having a higher withstand voltage than 8D-2V may be used, since the diameter of the electric wire 4 is large, it is difficult to route the electric wire 4 and the lamp in FIG. 1 cannot be easily moved. That is, the workability is deteriorated, which is not preferable.
[0026]
FIG. 3 is a diagram showing characteristics of the high-frequency coaxial cable called 8D-2V described above. As can be seen from this figure, 8D-2V has a withstand voltage of 1000V. Actually, a voltage of about 1/3 of the withstand voltage is applied to the cable, so that a voltage of about 300 V is approximately applied to the cable.
[0027]
Further, the right side of the expression (1) indicates a voltage actually applied to the electric wire 4. Therefore, if the right side is smaller than 300 V, stable continuous operation is performed for a long time. Therefore, in the present embodiment, the number N of the electric wires 4 is determined so as to satisfy the condition of the above equation (1).
[0028]
When the length of the electric wire 4 shown in FIG. 1 is equal to or longer than 波長 wavelength of the power supply frequency, a matching device that matches the output impedance of the power supply 3, the discharge impedance of the lamp 10, and the characteristic impedance of the cable is required. Without a matcher, signal reflection occurs and power loss increases. Therefore, in the present embodiment, the effective length of the electric wire 4 is set to be equal to or less than ８ wavelength of the power supply frequency so that the matching device is not required.
[0029]
FIG. 4 is a sectional view of a processing unit 11 incorporating the electrodeless discharge lamp 10 of FIG. As shown, the dielectric container 1 and the electrode 2 of FIG. 1 are housed in a protective container 12 and sealed by a metal flange 13. This prevents an accident in which a worker receives an electric shock to the electrode 2, prevents the electrode 2 from getting wet with water, and prevents electric leakage and the like.
[0030]
The protective container 12 is further incorporated in the processing unit 11. Between the outer wall of the processing unit 11 and the outer wall of the protective container 12, a path 14 through which a fluid to be sterilized flows is provided. This fluid flows into the processing unit 11 from the inlet 15 of the processing unit 11 and is discharged to the outside of the processing unit 11 from the outlet 16 through the periphery of the lamp in FIG. While the fluid passes around the lamp of FIG. 1, ultraviolet light emitted from the lamp impinges on the fluid and is sterilized or the like.
[0031]
The processing unit 11 shown in FIG. 4 is for sterilizing, disinfecting, and decolorizing water and sewage, deodorizing and decolorizing industrial water, bleaching pulp, or sterilizing medical equipment. Further, the fluid flowing into the processing unit 11 from the inlet 15 may include not only liquid but also gas and solid.
[0032]
The processing unit 11 of FIG. 2 is provided with only one electrodeless discharge lamp 10 of FIG. 1. However, as shown in FIG. Is also good.
[0033]
As described above, in the first embodiment, the electrode 2 having an aperture ratio of 70% or more is disposed outside the dielectric container 1 and a high-frequency voltage is applied to the electrode 2. Can be emitted, and sterilization of the sewer can be performed at low cost and in a short time.
[0034]
Further, since the number N of the electric wires 4 is set so as to satisfy the condition of the above-described expression (1), the thickness of the electric wires 4 does not need to be too large, the handling of the processing unit 11 becomes easy, and the workability is improved. improves.
[0035]
Further, since the effective length of the electric wire 4 is set to 1/8 wavelength or less of the power supply frequency, signal reflection does not occur without providing a matching unit for impedance matching, thereby reducing the size and cost of the entire device. Will be possible.
[0036]
(Second embodiment)
The second embodiment is characterized in that a coil-shaped electrode 2 is provided.
[0037]
FIG. 6 is a diagram showing a schematic configuration of a second embodiment of the electrodeless discharge lamp 10 which is an ultraviolet ray generating device according to the present invention. The electrodeless discharge lamp 10 of FIG. 6 includes a dielectric container 1 made of a dielectric material having a hollow inside and transmitting ultraviolet light, and a coil-shaped electrode 2 (hereinafter, coil electrode) wound around the outer peripheral surface of the container. Have. A capacitor C1, a coil L1, an electric wire 4, and a power supply 3 are connected in series between one end of the coil electrode 2 and a ground terminal, and the other end of the coil electrode 2 is grounded.
[0038]
A high-frequency current flows through the coil L1 by a high-frequency voltage from the power supply 3, and a magnetic field is generated based on the principle of an electromagnet. This magnetic field causes an eddy electric field inside the dielectric container 1 to generate a donut-shaped discharge ring, and ultraviolet rays effective for sterilization are emitted.
[0039]
The capacitor C1 is for preventing an inrush current from flowing when the coil electrode 2 is short-circuited, and is not necessarily an essential configuration.
[0040]
Although the electrodeless discharge lamp 10 in FIG. 6 is omitted in the drawing, the entire lamp is sealed and a treatment such as sterilization is performed so that the coil electrode 2 does not come into contact with the fluid.
[0041]
In the second embodiment, the AC frequency f _{OSC of the} power supply and the resonance frequency f _Z of the discharge unit of the dielectric container 1 are set to be substantially equal. _{Specifically,} it has to satisfy a relation condition of _{1.1f OSC> f Z> 0.9f OSC} . As a result, power loss due to signal reflection hardly occurs, and high-power ultraviolet light can be emitted with low power consumption.
[0042]
To adjust so as to satisfy the above condition, for example, it is conceivable to variably control the AC frequency f _OSC of the power supply 3. Alternatively, the resonance frequency f _Z may be variably controlled by changing the inductance of the capacitor and the coil L1 of the capacitor C1 in FIG.
[0043]
As described above, in the second embodiment, since the coil electrode 2 is provided on the outer peripheral surface of the dielectric container 1 to emit ultraviolet light, the aperture ratio can be set wider than in the first embodiment. Further, since the AC frequency f _OSC of the power supply 3 and the resonance frequency f _Z of the discharge unit of the dielectric container 1 are adjusted to be substantially equal, power consumption can be reduced.
[0044]
Incidentally, the coil electrode 2 does not necessarily need to be wound around the dielectric container 1 in a spiral shape. For example, FIG. 7 is a diagram illustrating an example in which a plurality of annular coil electrodes 2 are integrally formed on two electric wires 4 a and 4 b extending in parallel with the axial direction of the dielectric container 1. A power supply is connected to one of the wires 4 and the other wire 4 is grounded.
[0045]
Although the lamp 10 of FIG. 7 has a simple structure, the intensity of the ultraviolet light is higher on the side closer to the power supply 3 and the brightness becomes uneven.
[0046]
On the other hand, FIG. 8 is a diagram illustrating an example in which one electric wire 4a is connected to a power supply at one end of the dielectric container 1 and the other electric wire 4b is connected to a ground terminal at the other end of the dielectric container 1. . In the case of FIG. 8, substantially uniform ultraviolet light can be emitted over the entire dielectric container 1.
[0047]
On the other hand, FIG. 9 is a diagram showing an example in which one of the two electric wires 4 extending in the axial direction of the dielectric container 1 is arranged in a U-shape with the dielectric container 1 interposed therebetween. A coaxial cable 15 is connected to a voltage input portion of the electric wire 4. Use of the coaxial cable 15 can suppress unnecessary radiation of radio waves. In addition, since one of the electric wires 4 surrounds the dielectric container 1, unevenness in the brightness of the ultraviolet light hardly occurs.
[0048]
In FIG. 9, a plurality of coaxial cables 15 may be connected. In this case, as shown in FIG. 10, a plurality of coaxial cables 15 are connected in parallel, and the core wire of each coaxial cable 15 is connected to one electric wire 4 and the ground wire is connected to the other electric wire 4. By providing a plurality of coaxial cables 15, more high-frequency current can flow through the dielectric container 1, and strong ultraviolet light can be emitted.
[0049]
In FIG. 10, the power supply 3 is provided for each of the plurality of coaxial cables 15. However, as shown in FIG. 11, the plurality of coaxial cables 15 may be connected to one power supply 3.
[0050]
Also in the electrodeless discharge lamp 10 shown in FIGS. 6 to 11, it is desirable to set the number N of the electric wires 4 so as to satisfy the relationship of the above-described expression (2).
[0051]
【The invention's effect】
As described in detail above, according to the present invention, since ultraviolet light is emitted from between the electrodes arranged outside the cylindrical container, which is a dielectric container, so-called ball breakage does not occur and the life is extended. . In addition, since the electrodes are arranged so that the aperture ratio becomes 70% or more, strong ultraviolet light can be emitted, which can be widely used for sterilization of sewage and the like.
[0052]
Further, in order to provide two electric wires extending in the axial direction of the cylindrical container and a plurality of coil electrodes which surround the cylindrical container and are connected to the two electric wires at both ends at the both ends, a spiral shape is provided on the cylindrical container. It is possible to emit high-energy ultraviolet light without winding a coil electrode around.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a first embodiment of an electrodeless discharge lamp which is an ultraviolet ray generator according to the present invention.
FIG. 2 is a diagram showing a relationship between a frequency (MHz), an attenuation (dB / km), and a power capacity (W) of a high-frequency coaxial cable.
FIG. 3 is a diagram showing characteristics of a high-frequency coaxial cable called 8D-2V.
FIG. 4 is a sectional view of a processing unit incorporating the electrodeless discharge lamp of FIG. 1;
FIG. 5 is a diagram showing an example in which a plurality of electrodeless discharge lamps are provided.
FIG. 6 is a diagram showing a schematic configuration of a second embodiment of an electrodeless discharge lamp which is an ultraviolet ray generator according to the present invention.
FIG. 7 is a diagram showing an example in which a plurality of annular coil electrodes are integrally formed on two electric wires extending in parallel in the axial direction of the dielectric container.
FIG. 8 is a diagram showing an example in which one electric wire is connected to a power supply at one end of a dielectric container, and the other electric wire is connected to a ground terminal at the other end of the dielectric container.
FIG. 9 is a view showing an example in which one of two electric wires extending in the axial direction of the dielectric container is arranged in a U-shape with the dielectric container interposed therebetween.
FIG. 10 is a diagram showing an example in which a plurality of coaxial cables are connected in parallel, and a core wire of each coaxial cable is connected to one electric wire, and a ground wire is connected to the other electric wire.
FIG. 11 is a diagram showing a modification of FIG. 10;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Dielectric container 2 Electrode 3 Power supply 4 Electric wire 10 Electrodeless discharge lamp 11 Processing unit 12 Protective container 13 Metal flange 15 Inlet 16 Outlet

Claims (6)

An electrode disposed around a dielectric container capable of transmitting ultraviolet light,
A power supply for applying an AC voltage or a pulse voltage to the electrodes,
By applying an AC voltage or a pulse voltage to the electrode, an ultraviolet ray generator that emits ultraviolet light by causing a discharge inside the dielectric container,
The dielectric container is a hollow cylindrical container filled with a discharge gas therein,
The electrode is a coil electrode wound on the outer peripheral surface of the cylindrical container,
An ultraviolet generator comprising: a capacitor, a coil, and a power source connected in series between one end of the coil electrode and a ground terminal. An electrode disposed around a dielectric container capable of transmitting ultraviolet light,
A power supply for applying an AC voltage or a pulse voltage to the electrodes,
By applying an AC voltage or a pulse voltage to the electrode, an ultraviolet ray generator that emits ultraviolet light by causing a discharge inside the dielectric container,
The dielectric container is a hollow cylindrical container filled with a discharge gas therein,
Comprising two electric wires extending in the axial direction of the cylindrical container,
The electrode has a plurality of electrode portions arranged at a predetermined interval from each other in the axial direction of the cylindrical container,
The plurality of electrode units surround the cylindrical container, and are connected to the two electric wires at both ends of each electrode unit. An electrode disposed around a dielectric container capable of transmitting ultraviolet light,
A power supply for applying an AC voltage or a pulse voltage to the electrodes,
By applying an AC voltage or a pulse voltage to the electrode, an ultraviolet ray generator that emits ultraviolet light by causing a discharge inside the dielectric container,
The dielectric container is a hollow cylindrical container filled with a discharge gas therein,
Comprising two electric wires extending in the axial direction of the cylindrical container,
The electrode has a plurality of electrode portions arranged at a predetermined interval from each other in the axial direction of the cylindrical container,
These plurality of electrode portions surround the periphery of the cylindrical container, and are connected to the two electric wires at both ends of each electrode portion,
One of the electric wires is connected to the power supply at one end side of the cylindrical container,
The other electric wire is connected to a ground terminal at the other end of the cylindrical container. An electrode disposed around a dielectric container capable of transmitting ultraviolet light,
A power supply for applying an AC voltage or a pulse voltage to the electrodes,
By applying an AC voltage or a pulse voltage to the electrode, an ultraviolet ray generator that emits ultraviolet light by causing a discharge inside the dielectric body,
The dielectric container is a hollow cylindrical container filled with a discharge gas therein,
Comprising two electric wires extending in the axial direction of the cylindrical container,
The electrode has a plurality of electrode portions arranged at a predetermined interval from each other in the axial direction of the cylindrical container,
These plurality of electrode portions surround the periphery of the cylindrical container, and are connected to the two electric wires at both ends of each electrode portion,
An ultraviolet ray generator, wherein one of the electric wires is arranged in a U-shape with the dielectric container interposed therebetween. The ultraviolet generator according to claim 4, wherein the power supply is provided individually for each of the two electric wires. The ultraviolet ray generator according to claim 4, wherein a pulse voltage from the common power source is applied to the two electric wires.

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