JP2012256568A - Liquid processor using electrodeless discharge ultraviolet irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid processor with high efficiency having an electrodeless discharge ultraviolet irradiation device that can generate discharge almost uniformly over the whole length of a discharge tube effectively.SOLUTION: In a liquid processor having a discharge tube emitting an ultraviolet ray to a processing liquid arranged in a processing liquid passage from an inflow port of a liquid to be processed to an outflow port and passing through the passage, the discharge tube is formed in a tubular shape having a cavity penetrating the inside, and a ferrite core on which a plurality of induction coils are wound is arranged in the cavity. The plurality of induction coils are arranged on the ferrite core by being dispersed along a longitudinal direction of the discharge tube. Since the discharge tube is arranged so as to surround the outer periphery of the ferrite core on which the plurality of induction coils are dispersed and wound, there is no need to excite the coils at a high frequency, and the discharge can be generated uniformly over the whole length of the discharge tube without concentrating on one part of the discharge tube. Further, it has a simple configuration without need to provide means to cool the ferrite core.

Description

  The present invention relates to a liquid processing apparatus using an electrodeless discharge ultraviolet irradiation device that irradiates ultraviolet rays from an ultraviolet radiation discharge tube in response to high frequency excitation of an induction coil. In particular, the present invention relates to a technique for efficiently treating a liquid to be treated by causing a discharge to occur substantially uniformly over the entire length of the discharge tube.

  2. Description of the Related Art Conventionally, a liquid processing apparatus that performs liquid processing such as sterilization or organic substance removal by immersing and installing an ultraviolet radiation device directly in a drainage channel or a stream is known. In addition, there is a liquid processing apparatus that uses an ultraviolet radiation device to remove trace amounts of organic substances in the process of manufacturing ultrapure water, which is indispensable for manufacturing semiconductors and liquid crystals. As this ultraviolet radiation device, a fluorescent lamp is used and the tube material is changed to an ultraviolet transmissive quartz tube or the like.

By the way, in recent years, electrodeless discharge tubes having a long life have been put into practical use for general illumination. As this electrodeless discharge ultraviolet ray irradiation device, a ferrite core around which an induction coil is wound is disposed in the vicinity of an ultraviolet radiation discharge tube (hereinafter simply referred to as a discharge tube), and a high frequency current ( Or a high-frequency voltage) is applied to induce an annular electric field in the discharge tube so that ultraviolet rays are generated from the discharge tube and irradiated (for example, see Patent Document 1 shown below). . In the apparatus described in Patent Document 1, a stable donut-shaped discharge is generated in a discharge tube formed in a substantially spherical shape (specifically, a light bulb shape) by applying a high-frequency current (or voltage) to a coil. In response to this, radiation light peculiar to the sealed gas enclosed in the discharge tube is emitted. For example, the discharge tube is formed of glass that transmits ultraviolet light made of a material such as quartz, and when the constituent of the sealed gas sealed in the discharge tube is mercury, the discharge tube is Radiation such as a 254 nm germicidal line or a 185 nm vacuum ultraviolet ray is performed.
There is also an electrodeless low-pressure lamp in which a plurality of ferrite cores wound with an induction coil are arranged in a coaxial cylindrical discharge tube to improve the uniformity of light emission.

JP 2009-205819 A JP-A-10-269993 JP 2005-506676 Gazette

  By the way, in the electrodeless discharge ultraviolet irradiation device described in Patent Document 1, when the length of the discharge tube is several times or more of the diameter, the discharge is performed at a part of the total length of the discharge tube. It is easy and it is difficult to realize uniform discharge over the entire length of the discharge tube, which is unsuitable for a liquid processing apparatus. Therefore, as in the device described in Patent Document 2, a plurality of induction coils are arranged separately in the tube axis direction (longitudinal direction) in the discharge tube, and these coils are connected to discharge each coil. It is conceivable to make the discharge uniform over the entire length of the discharge tube by independently causing it to occur in parallel at a plurality of locations of the discharge tube.

  However, in the apparatus described in Patent Document 2, the induction coil disposed in the protective tube is an air-core coil that is simply wound around a hollow cylinder or the like, and has a high frequency (current or current) applied to the coil. The voltage (same below) is very high at several tens of MHz. Such a high frequency as high as several tens of MHz is unsuitable for exciting an induction coil wound around a ferrite core made of a magnetic material, and the device described in Patent Document 2 is a discharge tube (discharge lamp). Since the coil is wound around the outer periphery, simply replacing the cylindrical part disposed inside the discharge lamp around which the coil is wound with a ferrite core can efficiently generate discharge. I could not.

  Furthermore, since it is based on high-frequency excitation using an air-core coil of several tens of MHz, a coil portion and a liquid to be processed that are applied to a liquid processing apparatus for processing a liquid to be processed mainly including water having a high dielectric constant, Is relatively close, the high frequency power is absorbed by the liquid, resulting in useless high frequency power loss. Therefore, it is necessary to separate the liquid to be processed and the coil portion, and there is a disadvantage that the liquid processing apparatus becomes large. In this respect, Patent Document 3 improves the drawbacks of Patent Document 1 described above, but is not intended to be applied to a liquid processing apparatus. When applied as it is, it has liquid processing capabilities such as organic matter decomposition and sterilization. There was a drawback that could not be fully demonstrated.

  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 the liquid to be treated such as water has a high dielectric constant. This is a liquid processing device to which an electrodeless discharge ultraviolet irradiation device using a ferrite core is applied. This electrodeless discharge ultraviolet irradiation device efficiently causes a discharge to occur almost uniformly over the entire length of the discharge tube, so that desirable organic matter decomposition and sterilization can be achieved. It is an object of the present invention to provide a liquid processing apparatus capable of efficiently radiating the necessary ultraviolet rays.

  A liquid processing apparatus using an electrodeless discharge ultraviolet irradiation apparatus according to the present invention is disposed in a processing liquid channel having an inlet and an outlet for a liquid to be processed, and has no effect on the processing liquid passing through the channel. The electrode discharge ultraviolet radiation device irradiates ultraviolet rays. The electrodeless discharge ultraviolet irradiation device is a cylindrical ultraviolet discharge tube having a hollow portion penetrating the inside along a longitudinal direction, and the ultraviolet discharge tube is formed on a body portion surrounding an outer periphery of the hollow portion. A discharge medium enclosed therein, a ferrite core disposed in the cavity along the longitudinal direction of the discharge tube, and a plurality of induction coils wound around the ferrite core, The coils are distributed along the longitudinal direction of the discharge tube, and a high frequency magnetic field is applied to the discharge tube to cause discharge in the discharge tube, and the induction coil is connected via a lead wire. A high-frequency power source for supplying a high-frequency current or voltage, the high-frequency power source generating ultraviolet light in the ultraviolet discharge tube by energizing the induction coil. The electrodeless discharge ultraviolet radiation discharge tube is accommodated in a protective member made of a material that transmits these ultraviolet rays, and allows the liquid to be processed to flow outside the protective tube.

  According to the liquid processing apparatus using the electrodeless discharge ultraviolet irradiation device of the present invention, ultraviolet rays are generated from the ultraviolet discharge tube by supplying a high frequency current or voltage to the induction coil wound around the ferrite core via the lead wire. However, the discharge tube is formed in a cylindrical shape having a hollow portion penetrating the inside thereof, and a ferrite core around which the induction coil is wound is disposed in the hollow portion. In addition, there are a plurality of induction coils, and each induction coil is distributed along the longitudinal direction of the discharge tube and arranged (wound) on the ferrite core. That is, since a plurality of induction coils are dispersed and wound around a ferrite core, and a discharge tube in which a discharge medium is enclosed is disposed so as to surround the outer periphery thereof, power is absorbed by the liquid to be treated. There is no need to excite the coil at a high frequency that causes loss, and the discharge tube does not concentrate the discharge on a part of the discharge tube by causing the discharge by the coil to occur independently in parallel at multiple locations of the discharge tube. The liquid can be uniformly generated over the entire length, and the liquid can be processed over almost the entire processing liquid channel.

Since the discharge tube has a cylindrical shape, the discharge space can be made thinner and closer to the surface of the discharge tube as compared with the conventional case, so that there is an advantage that the radiation amount of vacuum ultraviolet rays effective for organic matter decomposition is increased. Furthermore, since such an electrodeless ultraviolet discharge tube has a longer life than the electroded discharge tube used in the past, the frequency of discharge tube replacement can be reduced compared to the conventional case. In addition, the energy transfer between the primary current of the coil and the secondary current of the discharge tube when exciting the discharge tube in response to energization of the induction coil using the ferrite core can be improved, and the ferrite core is not enlarged. However, energy can be easily transmitted efficiently from the high frequency power source side to the discharge tube side.
Furthermore, with such a configuration, when an organic substance or an inorganic substance in the liquid to be treated that causes a decrease in the transmittance of ultraviolet rays adheres to the surface of the protective tube, it can be easily cleaned.

  According to the present invention, since the plurality of induction coils are dispersed and wound around the ferrite core, and the discharge tube in which the discharge medium is enclosed so as to surround the outer periphery thereof is arranged in the liquid processing apparatus, It is not necessary to excite the coil at a high frequency, it can be excited at a relatively low frequency of several hundreds KHz, and even in liquids mainly composed of water with a high dielectric constant, high-frequency power loss can be reduced and efficient ultraviolet radiation is possible. It becomes. In addition, it is possible to generate a discharge by a coil independently in parallel at a plurality of locations of the discharge tube so that the discharge can be uniformly generated over the entire length of the discharge tube without concentrating the discharge on a part of the discharge tube, and The ultraviolet radiation necessary for the liquid treatment is effectively performed, and further, since it has a long life, the number of maintenance operations such as discharge tube replacement is greatly reduced.

It is a conceptual diagram which shows one Example of the liquid processing apparatus which concerns on this invention. It is a conceptual diagram which shows the example of the electrodeless discharge ultraviolet irradiation device applied to a liquid processing apparatus. It is a perspective view which shows another example of an electrodeless discharge ultraviolet irradiation device. It is a graph which shows the attenuation degree of 254 nm when the product of mercury atom density and a tube radius is made into a variable. It is a graph which shows the relationship between ambient temperature and mercury density.

  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 a liquid processing apparatus according to the present invention. In the liquid processing apparatus according to the present invention shown in FIG. 1, an electrodeless ultraviolet irradiation apparatus 1 as shown in FIG. 2 or FIG. 3 to be described later is disposed in a protective tube (protective member) O, and the protective tube O The liquid to be treated P is sealed so as not to enter, and is then placed in the treatment tank A so as to be immersed in the liquid P to be treated stored in the treatment tank A. In this embodiment, by subjecting the liquid to be treated P, which has flowed from the water conduit X on the left side of the drawing through the liquid inlet Aa to be treated and stored in the treatment tank A, to the ultraviolet rays by the electrodeless discharge ultraviolet ray irradiation device 1. Liquid processing such as sterilization of the liquid to be processed and control of organic substances (microorganisms, etc.) in the liquid to be processed is performed. The liquid P to be treated after the liquid treatment flows out from the treatment tank A as the purified water or the like through the liquid feed outlet X on the right side in the figure via the liquid outlet Ab to be treated. The protective tube O is not necessarily a tube, and may be made of, for example, a fluororesin applied to the outer peripheral surface of the electrodeless ultraviolet radiation discharge tube H of the electrodeless discharge ultraviolet irradiation device 1.

  As shown in FIG. 1, an electrodeless discharge ultraviolet irradiation apparatus 1 constituting a component of a liquid processing apparatus according to the present invention has a cylindrical electrodeless ultraviolet radiation discharge tube H having an axial length longer than its diameter. (Also referred to as an ultraviolet lamp), a single ferrite core F made of a magnetic material, a plurality of induction coils C (shown here as an example consisting of two coils C1, C2), and the induction coil A high-frequency power source (not shown) that excites C at high frequency and a lead wire W that connects each induction coil C are configured.

  Inside the discharge tube H is formed a hollow portion (hollow portion) H1 penetrating the inside from one open end to the other open end (that is, a cross section of the discharge tube H). Is formed in a circular shape), and one long ferrite core F is disposed along the tube axis in the hollow portion H1 (hollow portion). In this embodiment, the ferrite core F is also configured in the same cylindrical shape as the discharge tube H, and is disposed in the discharge tube H so as to be substantially coaxial with the discharge tube H. The total length of the ferrite core F is preferably 10 times or more the maximum diameter of the discharge tube H. Although not shown here, a support member for arranging the ferrite core F coaxially in the discharge tube H may be provided.

  On the other hand, the main body portion H2 other than the hollow portion H1 of the discharge tube H has a closed space formed using a material that transmits desired ultraviolet rays such as quartz, and radiates ultraviolet rays into the space. For example, mercury particles or mercury amalgam or the like that becomes a gas to be discharged is enclosed.

  Two induction coils C1 and C2 are wound around the outer periphery of the ferrite core F disposed in the hollow portion H1 at positions separated in the axial direction (longitudinal direction). These induction coils C (C1, C2) are connected in parallel by lead wires W. The lead wire W is drawn from one open end of the discharge tube H and can be connected to a high-frequency power source (not shown).

  The ultraviolet radiation by the discharge tube H having the above configuration will be described. When each induction coil C (hereinafter simply referred to as a coil) is simultaneously excited at high frequency by a high frequency power source via a lead wire W, the coil passes through the corresponding portion of the ferrite core F around which each coil C is wound. The magnetic flux induced by C passes. When a magnetic flux passes through the ferrite core F, an electric field is induced in the discharge tube H by the magnetic flux, and a discharge corresponding to each coil C occurs. As a result, each of the supplied coils C and the discharge plasma ring are coupled to each other, and the energy of each coil C is injected into the plasma, so that mercury particles or mercury amalgam enclosed in the main body H2 of the discharge tube H is obtained. The discharge discharge of ultraviolet rays due to is continuously generated. That is, in the electrodeless ultraviolet radiation discharge tube H, when the ferrite core F is excited by the high frequency power source via the coil C, a secondary induced electromotive force is generated in the discharge tube H formed in a long shape. As a result, discharge in the discharge tube H occurs. And since a part of mercury particle (or mercury amalgam) enclosed in the discharge tube H exists as gas, ultraviolet rays are efficiently radiated. Furthermore, since the discharge tube is configured in a cylindrical shape, the discharge space is narrowed, the internal plasma electron temperature is likely to rise, and the wavelength effective for organic matter decomposition is short compared to conventional columnar discharge tubes. Vacuum ultraviolet light etc. are emitted more intensely.

  As described above, one ferrite core F can be divided into a single ferrite core F without using a configuration in which the two induction coils C1 and C2 are wound around the ferrite core F at positions separated in the axial direction. In the case of a single configuration in which only a single coil is wound, particularly in a long discharge tube H whose tube axis direction is longer than the diameter, the discharge region is a negative characteristic of the discharge. As a result, the resistance component decreases and current tends to concentrate in the region. As a result, a phenomenon in which the discharge is more and more concentrated in the region occurs, so that uniform discharge light emission in the tube axis direction of the discharge tube H is inhibited. However, like the electrodeless discharge ultraviolet irradiation device 1 shown in this embodiment, a single ferrite core F having the same shape is disposed in the discharge tube H, and a plurality of coils C ( Here, two are shown as an example, but it may be two or more). By dividing the arrangement, discharge is performed for each coil C and concentrated on a specific portion of the discharge tube H. Discharge will not occur evenly. Therefore, substantially uniform discharge light emission can be obtained over the entire length of the discharge tube H.

  The plurality of coils C wound around the ferrite core F are not limited to being connected in parallel to the high-frequency power source via the lead wires, but may be connected in series. However, when the coils C are connected in parallel, the coil drive voltage from the high frequency power supply can be lowered, and the withstand voltage value of each component in the drive circuit in the high frequency power supply can be lowered. There is an advantage that the lifetime of the can be increased.

  In the present embodiment, from the viewpoint of operating efficiency of the ferrite core F, the higher the driving frequency of the coil C 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, when the driving frequency of the coil C by the high frequency power source is too low, the ferrite core F 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 driving frequency of the coil C by the high frequency power source is 20 kHz or more and 1 MHz or less.

That is, the permeability of the ferrite core F mu, when the magnetic field intensity and H, energy transferred from the high-frequency power supply to the discharge tube H through the ferrite core F is per unit volume of the ferrite core F "μfH ^2/2 Is represented. Therefore, since the amount of energy transfer per unit volume decreases as the frequency (f) decreases, the ferrite core F must be enlarged in order to transmit a certain amount of energy. For example, when driving at a frequency of 20 kHz, a ferrite core F having a size about 10 times larger than that when 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 C wound around the outer periphery of the ferrite core F, 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 F.

  Furthermore, when the liquid to be treated is a liquid mainly composed of water or the like that absorbs more high-frequency electromagnetic waves and has a large high-frequency power loss because of its high dielectric constant, if the driving frequency of the coil C is high, ultraviolet rays are emitted. The energy to be radiated is directly absorbed by the liquid to be treated without radiating ultraviolet rays, which causes a great power loss. Therefore, the driving frequency of the coil C is desirably 1 MHz or less. If it is 500 kHz or less, it is more desirable.

  Further, in this embodiment, since the discharge tube H is formed in a hollow cylindrical shape having both ends opened and penetrating through the inside as shown in FIG. 2, the discharge tube H can be easily manufactured. There is also an advantage that it is easy to insert and install the ferrite core F around which the coil C is wound so that the main body H2 of the discharge tube H covers the ferrite core F and the coil C. Furthermore, it is possible to easily attach an ultraviolet reflector so as to surround the outer periphery of the coil C and the ferrite core H (more specifically, on the inner wall surface of the discharge tube H, that is, on the inner peripheral side facing the ferrite core F). It is easy to attach an ultraviolet reflecting material), and the deterioration of the ferrite core F and the coil C due to the influence of the ultraviolet rays generated thereby can be prevented, and the periphery of the discharge tube H where an object to be irradiated is present. It is easy to increase the efficiency by increasing the amount of ultraviolet radiation to.

  Further, the inner tube and the outer tube of the discharge tube H are formed of different materials by forming the inner tube of the discharge tube H from hard glass or soft glass and the outer tube from quartz. It is good to form the discharge tube H which has the hollow part H1 inside by combining these. For example, the above-mentioned for protecting the ferrite core F and the coil C disposed in the hollow portion H1 from the ultraviolet rays emitted from the main body H2 by forming the inner tube with a material that does not transmit ultraviolet rays such as hard or soft glass. This eliminates the need to take protective measures such as attaching a UV-reflecting material or the like, thus reducing the cost. The inner tube made of hard or soft glass having a different expansion coefficient and the outer tube made of quartz are joined by so-called graded tubes in which a plurality of glasses with slightly different expansion coefficients are joined together. (An inclined tube) may be used.

  A discharge tube having a normal electrode has a life of about 20,000 hours at most due to the life of the electrode. However, the discharge using the ferrite core F of the electrodeless discharge ultraviolet irradiation device 1 which is a component of the liquid processing apparatus according to the present invention. Since the tube H has no electrode, its life is several times longer than that of the electroded discharge tube. However, apart from the case where the discharge tube H is made of ceramic such as alumina that hardly undergoes ultraviolet deterioration, when the discharge tube H is made of general quartz or the like, the quartz is constituted by vacuum ultraviolet radiation of 185 nm or the like. When the interatomic bond is cut and the volume of the quartz is changed, a fine crack is generated in the discharge tube H, and the discharge tube H itself may eventually be damaged. This may shorten the life of the discharge tube H. One cause.

  Here, when the hydroxyl group OH is present in the quartz in an amount of 100 ppm or more and the halogen element such as chlorine or fluorine is contained in an amount of 0.1 ppm or more, the generation of fine cracks due to the influence of vacuum ultraviolet light is small. I found it experimentally. This is because the transmittance of vacuum ultraviolet light is improved by the presence of halogen to reduce absorption in quartz, and the broken bond of quartz is restored by the presence of OH groups. Therefore, also in the electrodeless discharge ultraviolet irradiation device 1 according to the present invention, the hollow cylindrical discharge tube H is formed by containing 100 ppm or more of hydroxyl group OH and 0.1 ppm or more of halogen element such as chlorine or fluorine in quartz. Thus, the life of the discharge tube H is improved due to ultraviolet deterioration.

Further, the inner wall surface (inner circumference) of the discharge tube H of the electrodeless discharge ultraviolet irradiation device 1 that is a component of the liquid processing apparatus according to the present invention is coated with titanium oxide or the like that absorbs vacuum ultraviolet light, thereby discharging The penetration of vacuum ultraviolet rays into the quartz constituting the tube H can be suppressed, and the life of the discharge tube H can also be improved by doing so. Furthermore, as conventionally known, aluminum oxide or rare earth oxide is applied to the inside of the main body H2 of the discharge tube H, particularly on the outer peripheral surface side, so that the mercury enclosed in the discharge tube H can be reduced. Since the amount of adhesion can be reduced, this also prevents a decrease in the amount of ultraviolet radiation to the outside.
Of course, these measures described above may be used simultaneously. This is very advantageous since it can more effectively extend the life of the discharge tube H.

  As described in detail above, according to the liquid processing apparatus according to the present invention, the electrodeless discharge ultraviolet irradiation apparatus 1 that is a constituent element thereof is wound with a plurality of induction coils C dispersed and wound around the ferrite core F. The discharge tube H in which the discharge medium is enclosed is arranged so as to surround the outer periphery of the tube, and thus the tube axis without concentrating the discharge at a part in the tube axis direction of the discharge tube H. It was made possible to carry out almost uniformly over the entire length in the direction. Further, by using a cylindrical electrodeless discharge tube, such an electrodeless discharge tube H has a longer life than an electroded discharge tube, but by coating the inner wall surface of the discharge tube H, the discharge tube H The service life can be extended, and the decrease in output can be reduced. Furthermore, by making the drive frequency appropriate, the power loss of the ferrite core F can be reduced, and the high frequency power loss to the liquid to be processed can be reduced. It becomes possible to provide a liquid processing apparatus including the electrodeless discharge ultraviolet radiation apparatus 1 having these advantages and capable of performing long-life and stable discharge.

  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, as shown in FIG. 3, the ferrite core F disposed in the hollow portion H1 of the discharge tube H is divided into a plurality of parts (here, eight ferrite cores F1 to F8), and the plurality of ferrite cores F1 to F8. A liquid processing apparatus using an electrodeless discharge ultraviolet irradiation apparatus having a configuration in which one or more coils C are wound in association with each other may be used. Here, as an example, an example is shown in which eight coils C1 to C8 are arranged in association with each other for each ferrite core (wound).

  Generally, it is known that an inductance in which a coil is wound around an iron core has a current-limiting action due to leakage of magnetic flux, and thus exhibits a function as a ballast. Similarly, in the electrodeless discharge ultraviolet irradiation device 1 that is a component of the liquid processing apparatus according to the present invention, the ferrite core F around which the coil C is wound is divided into a plurality of divided ferrite cores F1. Since a gap is generated at the end faces where the adjacent ones of F8 face each other, a little magnetic flux leaks from there. This leakage magnetic flux causes a slight current limiting action to exhibit a ballast action. Therefore, since each of the coils C1 to C8 has a weak current limiting component, the electrodeless discharge ultraviolet irradiation device shown in FIG. It will occur in a wide and stable manner without being biased to the parts. Further, according to this configuration, it is possible to extend the life of each component of the drive circuit in the high frequency power source, that is, the life of the electronic ballast.

  When performing liquid processing such as sterilization of a liquid to be processed and decomposition of organic substances in the liquid to be processed with the liquid processing apparatus according to the present invention described above, it is one of the components of the liquid processing apparatus of the present invention as described above. The electrodeless discharge ultraviolet irradiation device 1 is arranged in the middle of the flow path of the liquid P to be treated, for example, buried in the processing tank A or exposed to the flow path, and this is provided by a high frequency power source arranged outside. It is good to operate. Here, in the case of the electrodeless discharge ultraviolet radiation device 1 using the mercury-filled discharge tube H, it is necessary to keep the mercury vapor pressure appropriate and optimize the ultraviolet radiation efficiency. By maintaining the coldest part temperature at an appropriate value.

  The temperature of the drainage (liquid P to be treated) is usually about 15 ° C to 30 ° C. For example, the 254 nm ultraviolet radiation optimum mercury ambient temperature in a discharge tube H having a radius of 1 cm (diameter 2 cm) is around 40 ° C., while the tube radius of the discharge tube H and the discharge tube H as shown in FIG. The amount of absorption of 254 nm ultraviolet light is determined by the product of mercury vapor pressure in the main body H2. Therefore, when the ambient temperature of mercury is high, the mercury density increases (that is, the amount of absorption increases), so that the attenuation of 254 nm ultraviolet rays increases and the output efficiency decreases. On the other hand, when the ambient temperature of mercury is low, the number of atoms that emit 254 nm ultraviolet light decreases, so that the radiation efficiency of 254 nm ultraviolet light decreases. In FIG. 4, the case where the ambient temperature of mercury is about 35 ° C. to about 45 ° C. is indicated by a square frame for convenience. However, if the product of the mercury vapor density and the tube radius is around the value enclosed by this square frame, it is 254 nm. The radiation efficiency will be optimal.

Next, the relationship between mercury density and temperature is shown in FIG. The square frame shown in the figure shows the case where the temperature is 15 ° C. to 30 ° C. for convenience. Here, assuming that the liquid to be treated is water to be sterilized at 25 ° C., and the discharge tube H is directly cooled to 25 ° C., the mercury density at that time is approximately 6 × 10 ²³ cm ^{−. From the} fact that it is known to be about ^3, the optimum radiation condition of 254 nm ultraviolet light is to set the tube radius of the discharge tube H to about 5 cm. Thus, the diameter of the discharge tube H is about 5 cm in radius and about 10 cm in diameter is the highest condition from the viewpoint of 254 nm ultraviolet radiation. However, since the temperature of the discharge tube H may rise above 25 ° C. in actual use, the tube radius of the discharge tube H may be several centimeters smaller than 5 cm in that case. In view of these, the maximum diameter of the discharge tube H may be 10 cm or less in diameter. In addition, when the discharge tube H becomes a temperature higher than the temperature of the liquid to be processed, it is natural that, for example, amalgam may be used as a device for reducing the mercury vapor pressure.

  When the electrodeless discharge ultraviolet irradiation device 1 as a component of the liquid processing apparatus according to the present invention as shown in FIG. 2 or FIG. It adheres to the surface of the discharge tube H and causes a decrease in ultraviolet output. Therefore, in order to prevent the discharge tube H from being contaminated, it is generally placed in the processing tank A after being accommodated in a protective tube O made of quartz or the like as shown in FIG. In such a case, in addition to the heat generation from the discharge tube H, there is heat generation from the ferrite core F, but since the discharge tube H does not directly contact the liquid P to be treated, the coldest part of the discharge tube H that affects the ultraviolet radiation efficiency. The temperature is kept correct. Furthermore, since the total length of the ferrite core F can be increased, the power density of the ferrite core F can be lowered. In addition to this, water having a high dielectric constant, which is the main component of the liquid to be treated, and high loss of high-frequency power, etc. On the other hand, since the drive frequency is not increased, heat generation is suppressed, and there is no malfunction due to excessive rise in the temperature of the ferrite core F.

  As a result of increasing the power density of the discharge tube H and increasing the power density of the ferrite core F, when the temperature of the ferrite core F increases, the ferrite core F has a hollow shape with a hole around its axis. It is a well-known fact that the ferrite core F can be cooled by sending air to the hollow part or by passing a heat pipe or a metal rod having good heat transfer. is there.

  In addition, from the viewpoint of the mechanical strength of the protective tube O protecting the electrodeless discharge ultraviolet irradiation device 1 and the price of the protective tube O, the practical discharge tube H has a maximum diameter of about 10 cm. Is almost consistent with the view from the product of optimum mercury density and pipe diameter. Thus, by limiting the diameter of the protective tube O, the price of the protective tube O can be reduced, and the liquid processing apparatus itself can be provided at a low cost.

DESCRIPTION OF SYMBOLS 1 ... Electrodeless ultraviolet radiation discharge apparatus A ... Processing tank Aa ... Liquid to be processed inlet Ab ... Liquid outlet to be processed C (C1-C8) ... Induction coil F (F1-F8) ) ... Ferrite core H ... Electrodeless ultraviolet radiation discharge tube H1 ... Hollow portion H2 ... Main body O ... Protective tube P ... Liquid to be treated W ... Lead wire X ...・ Water guide pipe

Claims (10)

A cylindrical ultraviolet discharge tube having a hollow portion penetrating the inside along a longitudinal direction, wherein the ultraviolet discharge tube is formed by enclosing a discharge medium in a body portion surrounding an outer periphery of the hollow portion. things and,
A ferrite core disposed in the cavity along the longitudinal direction of the discharge tube;
A plurality of induction coils wound around the ferrite core, wherein the induction coils are distributed along the longitudinal direction of the discharge tube, and a high-frequency magnetic field is applied to the discharge tube to cause the discharge Which causes discharge in the tube,
A high-frequency power source for supplying a high-frequency current or voltage to the induction coil via a lead wire, the high-frequency power source generating ultraviolet rays in the ultraviolet discharge tube by energizing the induction coil;
Provided on the outer periphery of the ultraviolet discharge tube, and an ultraviolet-transmissive protective member for protecting the discharge tube;
A liquid processing apparatus, which is disposed in a processing liquid channel having an inlet and an outlet for a liquid to be processed, and irradiates the processing liquid passing through the channel with ultraviolet rays to process the liquid to be processed.   2. The ferrite core according to claim 1, wherein a plurality of the ferrite cores are distributed along the longitudinal direction of the discharge tube, and the one or more induction coils are wound around each of the ferrite cores. 2. The liquid processing apparatus according to 1.   The liquid processing apparatus according to claim 1, wherein the plurality of induction coils are connected in series or in parallel to the high-frequency power source.   4. The liquid processing apparatus according to claim 1, wherein a total length of the ferrite core in the axial direction is 10 times or more a maximum diameter of the discharge tube. 5.   The liquid processing apparatus according to claim 1, wherein a maximum diameter of the discharge tube is 10 cm or less.   The liquid processing apparatus according to claim 1, wherein a frequency of the high-frequency power source when driving the induction coil is 20 kHz or more and 1 MHz or less.   7. The discharge tube according to claim 1, wherein the discharge tube is formed in a cylindrical shape, and the inner tube of the cylindrical discharge tube is made of glass while the outer tube is made of quartz. The liquid processing apparatus as described.   8. The liquid processing apparatus according to claim 1, wherein the hollow portion side of the discharge tube in which the induction coil and the ferrite core are arranged is covered with an ultraviolet reflecting material.   The inside of the main body of the discharge tube is covered with a protective film that prevents reaction with the discharge medium enclosed in the main body, and further absorbs ultraviolet light of 185 nm and does not pass through the main body. The liquid processing apparatus according to claim 1, wherein the liquid processing apparatus is coated.   10. The liquid processing apparatus according to claim 1, wherein the discharge tube is made of quartz containing OH groups at 100 ppm or more and halogens at 0.1 ppm or more.

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