JP2014093190A - Liquid treatment apparatus employing electrodeless discharge ultraviolet irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid treatment apparatus employing an electrodeless discharge ultraviolet irradiation device of which the lifetime is more prolonged than the prior arts.SOLUTION: An inner wall surface within a quartz electroless ultraviolet discharge tube in which a discharge medium is encapsulated, is covered with a material which shields or extinguishes ultraviolet rays of wavelengths equal to or less than 185 nm. Thus, when ultraviolet rays are generated in the ultraviolet discharge tube, since ultraviolet rays of wavelengths equal to or less than 185 nm are shielded or extinguished, it can be temporally delayed for the total quantity of received ultraviolet rays with the wavelength of 185 nm to reach about 700 W hour/cm. If the total quantity of received ultraviolet rays with the wavelength of 185 nm does not reach about 700 W hour/cm, cracking is prevented from being incurred by incurring binding/separation of quartz molecules and changing a density of the quartz constituting the discharge tube. Therefore, though the lifetime of the electrodeless ultraviolet discharge tube is longer than that of an electrode-fitted discharge tube originally, the lifetime can be further prolonged in comparison with the prior arts.

Description

  The present invention relates to a liquid processing apparatus using an electrodeless discharge ultraviolet irradiation device that emits ultraviolet rays from a discharge tube in response to high-frequency excitation of an induction coil. In particular, the present invention relates to a technique for delaying breakage of a quartz discharge tube due to cumulative exposure to ultraviolet rays.

  2. Description of the Related Art Conventionally, liquid processing apparatuses that perform liquid processing such as sterilization of liquid and oxidative decomposition of trace organic substances in liquid or decomposition of hardly decomposable organic substances are known. There is also known a liquid processing apparatus that removes a small amount of organic substances in the process of producing ultrapure water, which is indispensable for the production of semiconductors and liquid crystals. In these liquid processing apparatuses, mercury or the like is enclosed as a sealing gas in a discharge tube, and mainly radiates ultraviolet rays having a wavelength of 185 nm (called vacuum ultraviolet light) and ultraviolet rays having a wavelength of 254 nm (called germicidal ultraviolet light). An ultraviolet irradiation device is used. Recently, there is an electrodeless discharge ultraviolet irradiation device that uses a long-life fluorescent lamp configuration that uses an electrodeless discharge to change the material of the discharge tube to a quartz tube (such as a quartz glass tube) that transmits ultraviolet light. It has come to be used.

  Patent Document 1 shown below discloses an ultraviolet lamp for sterilization used for surface sterilization of food packaging materials. In this ultraviolet lamp, a zirconium oxide film is formed on the outer wall surface of a quartz glass bulb (discharge tube) provided with electrodes at both ends, thereby maintaining the intensity of ultraviolet light having a wavelength of 254 nm for sterilization while maintaining the human body. It has been carried out to reduce ultraviolet rays of 185 nm which generate ozone harmful to the environment.

JP 2011-23253 A

By the way, in a quartz discharge tube, when exposed to ultraviolet rays with a wavelength of 185 nm emitted from the discharge tube itself for a long time, innumerable fine cracks such as cracks and cracks particularly in a portion where the cumulative exposure amount of ultraviolet rays is large. Occurs. When the total amount of received 185 nm wavelength ultraviolet light per unit area of the quartz tube wall is about 700 Wh / cm ² , the inventor of the present application changes the quartz density due to the bond breaking of the quartz molecules, and the quartz tube wall is distorted. As a result, it was experimentally determined that a fine crack was generated in the quartz tube (discharge tube) and eventually damaged. Therefore, in order to extend the life of the ultraviolet irradiation device, it is possible to delay the time until the total received light amount (cumulative exposure amount) of the 185 nm wavelength ultraviolet light emitted from the discharge tube reaches about 700 Wh / cm ^2. As a result, it has been concluded that as a measure for that purpose, it is only necessary to block or diminish the 185 nm wavelength ultraviolet rays emitted along with the 254 nm wavelength germicidal line in accordance with the use of the ultraviolet irradiation device.

  Therefore, it is conceivable to use an ultraviolet lamp as described in Patent Document 1 for a liquid processing apparatus. This ultraviolet lamp is an electrode type using a filament electrode similar to a normal fluorescent lamp, and has a lifetime. However, since the lifetime is shorter than that of the electrodeless type, it is not suitable for use in a liquid processing apparatus. Further, since the ultraviolet lamp described in Patent Document 1 is designed to diminish / block ultraviolet rays having a wavelength of 185 nm radiated from the discharge tube on the outer surface of the discharge tube, it radiates from the discharge tube to the outside. Although it was possible to attenuate / block the 185 nm wavelength ultraviolet light, it was not possible to prevent the deterioration of the discharge tube (quartz tube) due to the 185 nm wavelength ultraviolet light.

  Thus, in the past, it has been clarified that, in the first place, bond breakage of quartz molecules is caused by ultraviolet rays having a wavelength of 185 nm, and accordingly, the density of quartz constituting the quartz tube (discharge tube) changes and cracks occur. Since it has not been made, no means has been considered for preventing deterioration and damage of the quartz discharge tube due to ultraviolet rays having a wavelength of 185 nm. Therefore, it has been difficult to provide a liquid processing apparatus that uses an electrodeless discharge ultraviolet irradiation apparatus that can be used for a longer period of time and has an unprecedented long life.

  The present invention has been made in view of the above points. Conventionally, it has been difficult to use an electrodeless discharge in an ultraviolet irradiation device, which is one of the main components, because of the high dielectric constant of a treatment liquid such as water. This relates to a liquid processing apparatus to which an electrodeless discharge ultraviolet irradiation device is applied. By delaying the occurrence of deterioration and damage of the discharge tube due to ultraviolet rays in this electrodeless discharge ultraviolet irradiation device, the electrodeless discharge has a longer life than conventional ones. An object of the present invention is to provide a liquid processing apparatus using an ultraviolet irradiation device.

  A liquid processing apparatus using an electrodeless discharge ultraviolet irradiation device according to claim 1 of the present invention is disposed in a processing liquid flow path provided with an inlet and an outlet of a processing liquid so that the processing liquid passes through the flow path. In contrast, an electrodeless discharge ultraviolet irradiation device emits ultraviolet rays. The electrodeless discharge ultraviolet irradiation device is a quartz electrodeless ultraviolet discharge tube in which a discharge medium containing mercury or a mercury alloy and a rare gas is enclosed in a tube, and the ultraviolet discharge tube is made of quartz molecules. A material in which the inner wall surface of the tube is coated with a material that blocks or attenuates ultraviolet light having a wavelength of 185 nm or less that can change the quartz density by bond breaking, and induction that causes a discharge by causing a high-frequency magnetic field to act on the ultraviolet discharge tube. A coil and a high-frequency power source for supplying a high-frequency current or voltage to the induction coil, the high-frequency power source generating ultraviolet light in the ultraviolet discharge tube by energizing the induction coil.

According to the liquid processing apparatus using the electrodeless discharge ultraviolet irradiation apparatus of the present invention, a quartz electrodeless ultraviolet discharge tube in a tube in which a discharge medium containing mercury or a mercury alloy and a rare gas is enclosed in the tube is provided. The inner wall surface is covered with a material that blocks or attenuates ultraviolet light having a wavelength of 185 nm or less. When the induction coil is energized to generate ultraviolet rays in the ultraviolet discharge tube, ultraviolet rays having a wavelength of 185 nm or less are blocked or dimmed by the inner wall surface of the tube. As a result, ultraviolet light having a wavelength of 185 nm or less is blocked or dimmed during use, so that the total amount of received light (cumulative exposure) of ultraviolet light having a wavelength of 185 nm reaches about 700 W / cm ^{2 in} terms of time. Can be delayed. If the total received light amount of ultraviolet rays with a wavelength of 185 nm does not reach about 700 Wh / cm ² , the quartz molecules are broken and the density of the quartz constituting the discharge tube does not change and cracks do not occur. Therefore, an electrodeless ultraviolet discharge tube has a longer life than an electroded discharge tube in the first place, but further has the advantage that it can have a longer life than conventional ones.

A liquid processing apparatus using an electrodeless discharge ultraviolet irradiation device according to claim 2 of the present invention is disposed in a processing liquid flow path having a processing liquid inlet and an outlet, and the processing liquid passes through the flow path. In contrast, an electrodeless discharge ultraviolet irradiation device emits ultraviolet rays. The electrodeless discharge ultraviolet irradiation device is an electrodeless ultraviolet discharge tube in which a discharge medium containing mercury or a mercury alloy and a rare gas is enclosed in a tube, and the ultraviolet discharge tube is formed by breaking a quartz molecule bond. A material produced by mixing quartz with a material that blocks or attenuates ultraviolet light having a wavelength of 185 nm or less that can change the quartz density, an induction coil that causes a high frequency magnetic field to act on the ultraviolet discharge tube, and A high-frequency power supply for supplying a high-frequency current or voltage to the induction coil, the high-frequency power supply including an ultraviolet ray generated in the ultraviolet discharge tube by energizing the induction coil. Also by this, by blocking or dimming ultraviolet light with a wavelength of 185 nm or less emitted from the discharge tube, the total amount of received light of ultraviolet light with a wavelength of 185 nm is delayed in time until it reaches approximately 700 Wh / cm ^2. The life of the discharge tube can be significantly extended.

According to the present invention, by covering the inner wall surface of the quartz electrodeless ultraviolet discharge tube made of quartz with a material that blocks or attenuates ultraviolet light having a wavelength of 185 nm or less, the total amount of received light of ultraviolet light having a wavelength of 185 nm is approximately. Since it can be delayed in time until it reaches about 700 Wh / cm ^2, it can provide a liquid processing apparatus using an electrodeless discharge ultraviolet irradiation apparatus that has a longer life than conventional ones, and the number of maintenance such as discharge tube replacement Has the effect of significantly reducing. Further, it is possible to easily radiate ultraviolet rays efficiently and stably and to effectively perform ultraviolet radiation necessary for liquid processing with a simple configuration.

It is a conceptual diagram which shows one Example of the whole structure of the liquid processing apparatus which concerns on this invention. It is a partially broken figure which shows the electrodeless discharge ultraviolet irradiation device shown in FIG. It is a perspective view which shows another Example of a discharge tube.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a conceptual diagram showing an embodiment of the overall configuration of a liquid processing apparatus according to the present invention. A liquid processing apparatus 1 shown in FIG. 1 is provided in a cylindrical container A (for example, a cylindrical container but is not limited to this, but also called a cylinder) made of a material that hardly corrodes, such as stainless steel. An electrodeless discharge ultraviolet irradiation device 2 as shown in the figure can be detachably attached to the treatment liquid P passing through the cylindrical container A by ultraviolet rays emitted from the electrodeless discharge ultraviolet irradiation device 2. This is a type that performs liquid treatment.

  The cylindrical container A (cylinder) is provided with a mounting portion Ac for mounting the electrodeless discharge ultraviolet irradiation device 2, and the electrodeless discharge ultraviolet irradiation device 2 is attached to the cylindrical container A (cylinder) by a mounting member such as a screw N via the flange 2 a. It is attached to the attachment portion Ac and is fixedly supported by the cylindrical container A. Since the attachment portion has a through hole reaching the inside of the cylindrical container A, the electrodeless discharge ultraviolet irradiation device 2 is partially protruded from the through hole into the cylindrical container A as shown in the figure. It is fixed to the cylindrical container A.

  And this cylindrical container A is liquid-tightly sealed so that the processing liquid P does not leak to the outside by the sealing part F at both ends thereof, and the processing on the left side in the figure provided on the side surface of the container A A flow path is formed through which the processing liquid P (indicated by a dotted arrow in the figure) taken from the liquid inlet Aa is discharged from the processing liquid outlet Ab on the right side of the figure provided on the side surface of the container A. For this reason, in the liquid processing apparatus 1 shown in FIG. 1, when the processing liquid P flowing from the processing liquid inlet Aa passes through the cylindrical container A, the electrodeless discharge ultraviolet irradiation apparatus 2 protruding into the cylindrical container A is used. The emitted ultraviolet rays are emitted to the processing liquid P passing through the flow path, and liquid processing such as sterilization of the processing liquid P and control of organic substances (microorganisms and the like) in the processing liquid P is performed. At this time, the electrodeless discharge ultraviolet irradiation device 2 emits ultraviolet light having a wavelength of, for example, 260 nm or less, typically ultraviolet light having a wavelength of 254 nm or 185 nm. If the wavelength of the ultraviolet light is around 254 nm, the bactericidal effect is 185 nm. If it is before and after, the organic matter decomposition effect appears remarkably. The treated liquid P after the liquid treatment flows out from the treated liquid outlet Ab as purified water or the like.

  FIG. 2 is a partially cutaway view showing an embodiment of the electrodeless discharge ultraviolet irradiation device 2. As shown in FIG. 2, an electrodeless discharge ultraviolet irradiation device 2 constituting a component of the liquid processing apparatus 1 according to the present invention includes a stainless casing member 21 that houses a discharge tube lighting circuit portion (not shown), It is combined with quartz or Teflon (registered trademark) discharge tube housing tube (also referred to as a protective tube, hereinafter simply referred to as a housing tube) 22 that transmits ultraviolet rays. Although not shown, the discharge tube lighting circuit unit includes a drive circuit for exciting the induction coil E (more specifically, a ferrite core coil or an air core coil) at high frequency, and external high frequency signals for supplying power to them. Connected to power.

  On the other hand, in the internal space secured by combining the casing member 21 and the housing tube 22, an electrodeless ultraviolet radiation discharge tube H made of quartz (hereinafter simply referred to as a discharge tube) and a ferrite core C made of a magnetic material are used. And an induction coil E (winding) wound around the ferrite core C, and a heat radiation fin D that dissipates heat generated from the ferrite core C and / or the induction coil E due to high-frequency excitation of the induction coil E. Has been. In this configuration, when the electrodeless discharge ultraviolet irradiation device 2 is attached to the cylindrical container A as described above, the storage tube 22 includes the discharge tube H, the ferrite core C (including the induction coil E), and the radiation fin D. , So as to be isolated from the processing liquid P.

  The discharge tube H shown in this embodiment includes a discharge medium containing, for example, mercury particles or mercury amalgam (mercury alloy), which is a gas that emits ultraviolet rays, and a rare gas such as xenon, krypton, argon, or neon. Is a double tube-shaped electrodeless mercury discharge tube enclosed in a tube, and emits ultraviolet rays having a wavelength of 185 nm and a wavelength of 254 nm by being driven by electromagnetic waves by a ferrite core coil. That is, when a high frequency current or voltage is supplied from a high frequency power source, the induction coil E is energized to excite high frequency electromagnetic waves, thereby generating ultraviolet rays from the discharge tube H. As shown in FIG. 2, an induction coil E is wound around an outer periphery of a long ferrite core C to form a ferrite core coil, and the discharge tube H is disposed so as to surround the ferrite core coil. In other words, the discharge tube H may have any shape as long as it can surround the ferrite core coil. For example, the example shown in FIG. 2 is a hemispherical (egg-shaped, semi-elliptical) discharge tube H having a depression (cavity) in the center, and a ferrite core coil is disposed in the depression. It is a shape that can be made. With such a shape, ultraviolet rays can be efficiently emitted.

  The induction coil E is made of a good conductor such as silver, copper, or aluminum, or a hardly corrosive metal such as nickel or stainless steel. The surface of the induction coil E may be coated with an ultraviolet resistant material such as Teflon (registered trademark). When the ambient temperature of the discharge tube H becomes high, mercury amalgam may be enclosed in the discharge tube H in order to ensure an optimum mercury vapor pressure.

  In the present embodiment, the inner wall surface of the discharge tube H in which the discharge medium is sealed has at least ultraviolet light of about 185 nm or less, which is vacuum ultraviolet light emitted by mercury discharge (more specifically, with long-term radiation). The quartz molecules are bonded and cut off to block or attenuate (ultraviolet rays having a wavelength of 185 nm or less that can change the density of quartz constituting the discharge tube H), for example, yttrium oxide, zirconium oxide, zinc oxide, titanium oxide, etc. A metal oxide film B made of the above material is formed (coated). Alternatively, the discharge tube H itself may be generated by mixing metal oxides such as yttrium oxide, zirconium oxide, zinc oxide, and titanium oxide described above into quartz.

  Further, a protective film (such as a rare earth metal oxide film or an aluminum oxide film) is provided on the inner wall surface of the discharge tube H in order to prevent mercury atoms or mercury compounds from adhering to the quartz tube wall due to discharge and lowering the ultraviolet output. (Not shown) may be formed. In general, the protective film for preventing the mercury atoms from adhering to the tube wall and the metal oxide film B for dimming or blocking the 185 nm wavelength ultraviolet light are separated on the inner wall surface of the discharge tube H as separate films. Although formed separately, it is needless to say that it may be formed on the inner wall surface of the discharge tube H as one type of film that serves as both.

  Suitable materials for dimming or blocking ultraviolet rays having a wavelength of 185 nm include metal oxides such as yttrium oxide, zirconium oxide, zinc oxide, and titanium oxide. In the present embodiment, as described above, the discharge tube H is formed by forming those thin films on the inner wall surface of the discharge tube H or by mixing the metal oxide into quartz to create the discharge tube H itself. The irradiation amount of the 185 nm wavelength ultraviolet light emitted from the discharge tube H and radiated to the wall surface of the discharge tube H is suppressed as compared with the conventional case, and the breakage of the discharge tube H due to the cumulative exposure of ultraviolet rays is delayed (details will be described later). To do). Note that a quartz tube formed as a tube by mixing titanium oxide into a quartz material is commercially available as an ozoneless quartz tube.

  The evaluation result of the discharge tube breakage due to the cumulative exposure of ultraviolet rays in the electrodeless discharge ultraviolet irradiation device 2 of the present embodiment will be described in comparison with the conventional device. As described above, in a quartz electrodeless discharge tube H in which the metal oxide film B is formed on the inner wall surface as means for suppressing ultraviolet rays having a wavelength of 185 nm (outer tube φ85 mm, inner tube φ32 mm, length 200 mm), mercury Evaluation results when the discharge tube H is continuously lit under the condition that a mercury alloy containing 10 mg of mercury and argon gas is sealed in 67 Pascals (0.5 torr) and 200 W of electric power (lamp input) is supplied from a high frequency power source. However, in the case where the electrodeless discharge ultraviolet irradiation device 2 of the present embodiment is used, even if the use accumulated time has passed 60,000 hours, the quartz tube (discharge tube H) is not cracked finely. No change was seen.

On the other hand, when a conventional electrodeless discharge ultraviolet irradiation device that does not take measures to suppress ultraviolet rays having a wavelength of 185 nm under the same conditions is used, a quartz tube (discharge tube H) is used after about 10,000 hours have elapsed. Strain due to the influence of ultraviolet rays began to appear, and after about 20,000 hours, fine cracks were generated. Further, when the lamp is continuously turned on, the crack becomes large and the discharge tube H is damaged. Although there are variations, in the conventional apparatus, when the total amount of received light of 185 nm wavelength per unit area of the inner wall surface of the electrodeless discharge tube H is about 700 W / cm ² , fine cracks begin to appear in the discharge tube H. Further, it was confirmed from the results of experiments conducted by the inventors of the present invention that the use of the product finally led to breakage. In particular, the higher the lamp input, the greater the amount of ultraviolet radiation with a wavelength of 185 nm, the larger the discharge tube power, the smaller the discharge tube volume, and the higher density power type discharge tube, the shorter the distortion occurs on the tube wall of the discharge tube and the smaller the crack Tend to occur. Therefore, it is an essential technique to reduce ultraviolet rays (vacuum ultraviolet light) having a wavelength of 185 nm generated by mercury atoms in a high-density ultraviolet radiation and long-life electrodeless discharge ultraviolet irradiation apparatus. Therefore, the inventors of the present application have means for suppressing ultraviolet rays (vacuum ultraviolet light) having a wavelength of at least 185 nm as described above for the quartz electrodeless discharge tube H in the electrodeless discharge ultraviolet irradiation device using mercury emission. As a result, it has been found that an electrodeless discharge ultraviolet irradiation device having a longer life than conventional ones can be realized.

  Further, mercury compounds such as mercury oxide and mercury nitride produced by combining with air components and exhaust system oil components mixed in the discharge tube H as mercury atoms or impurities in the discharge tube H are discharged into the discharge tube. If a protective film made of rare earth metal oxide, aluminum oxide or the like is formed on the inner wall surface of the discharge tube H in order to prevent the ultraviolet light output from decreasing due to adhering to the H tube wall, the electrodeless discharge ultraviolet ray having a longer life can be obtained. An irradiation apparatus can be obtained. Among rare earth oxides, for example, yttrium oxide and cerium oxide are materials that serve to both reduce / block ultraviolet rays with a wavelength of 185 nm and prevent mercury atom adhesion. Therefore, the above-described metals such as yttrium oxide and cerium oxide are used. It is advantageous to form the oxide film B.

  Further, as shown in FIG. 2, in order to isolate from the processing liquid P, the discharge tube H and the like are housed in a housing tube 22 made of quartz, Teflon (registered trademark), or the like. Also in the housing tube 22, the housing tube 22 is deteriorated by ultraviolet rays having a wavelength of 185 nm radiated from the discharge tube H, so that the housing tube 22 may be broken due to cracks similarly to the discharge tube H. Therefore, in order to prevent this, it is preferable to form a titanium oxide film or the like on the outer wall surface of the discharge tube H to block or reduce ultraviolet light having a wavelength of 185 nm.

In addition, since the electrodeless discharge ultraviolet irradiation device 2 emits ultraviolet rays having a wavelength of 254 nm, not only sterilization but also unpleasant substances and harmful substances such as SH bonds (87.9 kcal / mol), It is also effective for decomposing substances whose molecular bond energy is lower than that of ultraviolet light having a wavelength of 254 nm, such as decomposition of ozone O ₃ . For example, the photon energy of 6 × 10 ²³ (1 mol) UV light having a wavelength of 254 nm corresponds to 112.8 kcal / mol, and is necessary to move 6 × 10 ²³ (1 mol) electrons. When expressed in terms of voltage, it becomes 4.89 eV (electron volt), so that molecular bonds having a lower binding energy can be decomposed.

  In order to suppress the ultraviolet ray having a wavelength of 185 nm and obtain a strong ultraviolet ray having a wavelength of 254 nm, in the electrodeless discharge ultraviolet irradiation device 2 in which mercury or a mercury alloy and a rare gas are enclosed and excited by electromagnetic waves, The gas pressure of the sealed gas sealed in the discharge tube H is more effective as the gas pressure is lower, such as argon gas, a mixed gas of argon and neon, or a mixed gas of rare gas such as argon, neon, krypton, and xenon. For this reason, 133 Pa (1 torr) or less is desirable. In addition, such a low voltage is advantageous because the discharge starting voltage is also low, so that power consumption is low.

  In this embodiment, an electrodeless discharge tube H is used in the first place. Since the electrodeless discharge tube H has a life several times to several tens of times longer than that of the electroded discharge tube and does not require maintenance, the liquid processing apparatus 1 using the electrodeless discharge ultraviolet irradiation device 2 is used. Manufacturing and operating costs can be kept low.

  When performing liquid processing such as sterilization of the processing liquid P or decomposition of organic substances in the processing liquid P with the liquid processing apparatus 1 according to the present invention described above, one of the components of the liquid processing apparatus 1 of the present invention as described above. In order to extend the life of the electrodeless discharge ultraviolet irradiation apparatus 2 as described above, an electrodeless discharge system driven by electromagnetic waves without using electrodes is employed. In order to effectively drive the drive electromagnetic wave into the discharge tube H in the electrodeless discharge ultraviolet irradiation device 2, it is preferable to use a ferrite core coil having a ferrite core C such as an iron core that collects magnetic flux. It is preferable to use a ferrite core C with little loss. When a ferrite core coil is used, if the frequency is high, the heat loss of the ferrite core C increases and the allowable operating temperature upper limit (Curie temperature) of the ferrite core C is exceeded. Therefore, it is desirable to drive the ferrite core coil at a frequency of 5 MHz or less.

  On the other hand, in the case of an air-core coil, it is desirable to drive the air-core coil at a frequency below the legally allowed ISM band (13.56 MHz).

  Furthermore, since the treatment liquid P has a high dielectric constant and absorbs more high-frequency electromagnetic waves and is a liquid mainly composed of water having a high high-frequency power loss, the driving frequency of the coil E is high. Energy that should radiate ultraviolet rays is directly absorbed by the treatment liquid without radiating ultraviolet rays, causing a great power loss. Therefore, the drive frequency of the ferrite core coil or air core coil is desirably 1 MHz or less.

  From the viewpoint of operating efficiency of the ferrite core C, the higher the driving frequency of the ferrite core coil by the high frequency power source, the higher the loss. Therefore, it is desirable that the driving frequency is not as high as possible. On the other hand, if the drive frequency of the ferrite core coil by the high frequency power source is too low, the ferrite core C must be thickened, that is, the diameter must be increased, which is disadvantageous in terms of cost. In view of these, it is desirable that the drive frequency of the ferrite core coil by the high frequency power source is 20 kHz or more and 1 MHz or less.

That is, the permeability of the ferrite core C mu, when the magnetic field intensity and H, energy transferred from the high-frequency power supply to the discharge tube H through the ferrite cores C are per unit volume of the ferrite core C "μfH ^2/2 Is represented. Therefore, since the amount of energy transfer per unit volume decreases as the frequency (f) decreases, the ferrite core C must be enlarged in order to transmit a certain amount of energy. For example, in the case of driving at a frequency of 20 kHz, a ferrite core C that is about 10 times larger than that in the case of driving at a frequency of 200 kHz is required. Therefore, in the present embodiment, the lower limit of the driving frequency for generating ultraviolet rays from the discharge tube H is determined by the driving frequency to the coil E wound around the outer periphery of the ferrite core C, preferably 20 kHz or more (more preferably 50 kHz). It is preferable to adjust so as to drive at the above frequency. By doing so, it is possible to easily transfer energy from the high-frequency power source to the discharge tube H without having to enlarge the ferrite core C. That is, the use of a ferrite core coil can radiate ultraviolet rays more efficiently and stably than an air-core coil.

As described in detail above, according to the liquid processing apparatus 1 of the present invention, ultraviolet light having a wavelength of 185 nm is applied to the inner wall surface (inner circumference) of the quartz discharge tube H of the electrodeless discharge ultraviolet irradiation apparatus 2 that is a constituent element thereof. By forming a metal oxide film that reduces or blocks (vacuum ultraviolet light), or by using a discharge tube H prepared by mixing metal oxide into quartz, the total amount of received light (cumulative exposure) of 185 nm wavelength ultraviolet light The amount) can be delayed in time until it reaches approximately 700 Wh / cm ^2, so that the life of the discharge tube H can be significantly extended. Furthermore, by using a ferrite core coil, it is possible to easily and efficiently emit ultraviolet rays. If the filled rare gas pressure is 1 torr (133 Pascal) or less, the ultraviolet radiation efficiency can be easily increased. By simply forming a protective film on the inner wall surface of the discharge tube H, the life of the discharge tube H can be extended. By setting the drive frequency to 50 kHz or higher, the ultraviolet radiation ability is high and the ultraviolet radiation can be easily radiated efficiently. In addition, when the processing liquid P and the discharge tube H are arranged in a largely separated manner, the ultraviolet rays can be radiated efficiently with high ultraviolet radiation ability by driving at a frequency of the ISM band or lower. Can be easily done. On the other hand, when the processing liquid P and the discharge tube H are arranged close to each other, driving with a frequency of 5 MHz or less, more desirably 1 MHz or less, emits ultraviolet rays with high ultraviolet radiation capability and high efficiency. Can be easily done. It is possible to provide the liquid processing apparatus 1 having the electrodeless discharge ultraviolet irradiation apparatus 2 that has these advantages and performs longer-lasting and stable discharge than the conventional one.

  Furthermore, for example, when the UV irradiated object is food or a product related to its raw material, and ultraviolet light having a wavelength of 185 nm is emitted together with ultraviolet light having a wavelength of 254 nm, the taste of the food is changed by the decomposition action of the ultraviolet light having a wavelength of 185 nm. (Change in taste) occurs, but according to the present embodiment, ultraviolet rays having a wavelength of 185 nm are blocked or greatly reduced, so that a good sterilization result can be obtained without causing such taste change. Was found to be. For example, when used for sterilization of milk, if the UV light at 185 nm wavelength is not blocked, the taste changes that the milk becomes smoky, but if the UV light at 185 nm wavelength is blocked, such a change in taste is not seen, and A good sterilization condition was obtained.

  As mentioned above, although an example of embodiment was demonstrated based on drawing, this invention is not limited to this, It cannot be overemphasized that various embodiment is possible. For example, in the electrodeless discharge ultraviolet irradiation device 2 that is a constituent element of the liquid processing apparatus 1 according to the present invention, the discharge tube may have a configuration as shown in FIG. That is, the discharge tube H is formed with a hollow portion (hollow portion) Ha penetrating the inside from one open end to the other open end (that is, the discharge tube H has a circular cross section). The elongated ferrite core C is disposed along the tube axis in the hollow portion Ha (hollow portion). In the embodiment shown here, for example, a ceramic ferrite core C is formed in a cylindrical shape similar to that of the discharge tube H, and is disposed in the discharge tube H so as to be substantially coaxial with the discharge tube H. . In this embodiment, the induction coil E is wound around the outer periphery of the discharge tube H instead of the ferrite core C. Of course, also in the embodiment of FIG. 2 described above, the induction coil E may be wound around the outer periphery of the discharge tube H in which the ferrite core C is disposed. Conversely, it goes without saying that the induction coil E may be wound around the ferrite core C in the embodiment of FIG. Further, although not shown, it is obvious that a ring-shaped ferrite core in which a coil is suspended in a loop-shaped discharge tube may be linked.

  In addition, as the liquid processing apparatus 1 according to the present invention, an electrodeless discharge ultraviolet irradiation device 2 as shown in FIG. 1 is immersed in the processing liquid P stored in a processing tank, and the electrodeless discharge ultraviolet irradiation device is used. It may be of a type that performs liquid treatment by radiating ultraviolet rays emitted from 2 to the treatment liquid P existing around the discharge tube H.

DESCRIPTION OF SYMBOLS 1 ... Liquid processing apparatus 2 ... Electrodeless ultraviolet irradiation apparatus 21 ... Casing member 22 ... Discharge tube accommodating tube A ... Cylindrical container (sealed container)
Aa ... Treatment liquid inlet Ab ... Treatment liquid outlet B ... Metal oxide film C ... Ferrite core D ... Radiation fin E ... Inductive coil F ... Sealing part H ... -Electrodeless ultraviolet radiation discharge tube Ha ... Hollow part N ... Screw P ... Treatment liquid

Claims (6)

An electrodeless ultraviolet discharge tube made of quartz in which a discharge medium containing mercury or a mercury alloy and a rare gas is enclosed in a tube, and the ultraviolet discharge tube can change the quartz density by breaking the binding of quartz molecules. The inner wall surface of the tube covered with a material that blocks or attenuates ultraviolet light having a wavelength of 185 nm or less;
An induction coil that causes a discharge by causing a high-frequency magnetic field to act on the ultraviolet discharge tube;
A high-frequency power source for supplying a high-frequency current or voltage to the induction coil, the high-frequency power source comprising: generating ultraviolet rays in the ultraviolet discharge tube by energizing the induction coil;
A liquid processing apparatus that is disposed in a processing liquid flow path having a processing liquid inlet and an outlet and irradiates the processing liquid passing through the flow path with ultraviolet rays to process the processing liquid. An electrodeless ultraviolet discharge tube in which a discharge medium containing mercury or a mercury alloy and a rare gas is enclosed in a tube, the ultraviolet discharge tube having a crystal density of 185 nm or less capable of changing a quartz density by bond breaking of quartz molecules Produced by mixing quartz with a material that blocks or attenuates ultraviolet light of wavelength,
An induction coil that causes a discharge by causing a high-frequency magnetic field to act on the ultraviolet discharge tube;
A high-frequency power source for supplying a high-frequency current or voltage to the induction coil, the high-frequency power source comprising: generating ultraviolet rays in the ultraviolet discharge tube by energizing the induction coil;
A liquid processing apparatus that is disposed in a processing liquid flow path having a processing liquid inlet and an outlet and irradiates the processing liquid passing through the flow path with ultraviolet rays to process the processing liquid.   The ultraviolet discharge tube is a cylindrical double tube having a hollow portion penetrating the inside along the longitudinal direction or a hemispherical double tube having a hollow portion, the double tube The liquid processing apparatus according to claim 1, wherein the discharge medium is sealed in a tube of 1 torr or less.   The liquid processing apparatus according to claim 1, further comprising a storage tube that stores the ultraviolet discharge tube.   5. The liquid processing apparatus according to claim 1, wherein an inner wall surface of the ultraviolet discharge tube is covered with a protective film that prevents a reaction with a discharge medium sealed in the tube.   A ferrite core is further provided, wherein the induction coil is wound around the ferrite core or the ultraviolet discharge tube, and the frequency of the high-frequency power source when driving the induction coil is 5 MHz or less and 50 kHz or more. The liquid processing apparatus according to claim 1.

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