JP2013180249A - Water purification device - Google Patents

Abstract

An object of the present invention is to provide a water purification apparatus that generates active oxygen species such as ozone and OH radicals with high efficiency.
A standing wave 13 is generated in a liquid to be processed by an ultrasonic vibrator 7a and an ultrasonic vibrator 7b that vibrate in the liquid to be processed. When a high voltage pulse is applied between the electrode 5a and the electrode 5b in a state where the bubble 12 is captured at a position corresponding to the node of the standing wave 13, a discharge occurs through the bubble 12, and the inside of the bubble 12 Active oxygen species such as ozone and OH radicals are generated in the surrounding area. Since active oxygen species such as ozone and OH radicals have a strong oxidizing power, the action eliminates microorganisms and decomposes organic substances contained in the liquid to be treated, and can be used as a water purification device. In the node portion of the standing wave 13 where the bubbles 12 are trapped, discharge is performed between the adjacent electrodes 5a and 5b, so that ozone and OH radicals can be generated efficiently.
[Selection] Figure 3

Description

  The present invention relates to a water purification apparatus that generates active oxygen species by applying a high voltage between electrodes and disinfects microorganisms and decomposes organic substances contained in a liquid to be treated by the action of the active oxygen species. is there.

  As a conventional water purification device, a water purification device that purifies a liquid to be treated by the action of active oxygen species such as ozone and OH radicals generated by discharge by applying a high voltage between a pair of electrodes is known ( For example, see Patent Document 1 below).

  Hereinafter, the water purification apparatus will be described with reference to FIG.

  As shown in FIG. 8, a rod-like electrode 104 and a ring-like electrode 105 having an opening at the center are provided in a main body 103 having an inlet 101 and an outlet 102 through which a liquid to be treated flows. The tip of the rod-shaped electrode 104 is electrically exposed, and the rod-shaped electrode 104 and the ring-shaped electrode 105 are electrically connected to the high-voltage pulse power source 106. A bubble generating means 107 is provided at the lower part of the main body 103. The bubble generating means 107 is connected to an air introducing means 108 that is a pump by a pipe 109.

  In such a configuration, the liquid to be processed is introduced into the main body 103 from the inlet 101 and discharged from the outlet 102. At the same time, the bubbles 110 are introduced into the liquid to be processed by the bubble generation means 107 from the air introduction means 108 via the pipe 109. The bubble 110 rises in the main body 103 by its buoyancy and passes through the opening of the ring electrode 105. When a high voltage pulse is applied between the rod-shaped electrode 104 and the ring-shaped electrode 105 by the high-voltage pulse power supply 106, a discharge is performed through the bubbles 110 existing between the rod-shaped electrode 104 and the ring-shaped electrode 105, and the bubbles 110 Active oxygen species such as ozone and OH radicals are generated inside and around the site. Since active oxygen species such as ozone and OH radicals generated inside the bubble 110 have strong oxidizing power, the action eliminates microorganisms contained in the liquid to be treated and decomposes organic substances, which can be used as a water purification device. It can be done.

  As another water purification device, there is known a water purification device that generates active oxygen species such as ozone and OH radicals in the bubbles by discharging through the bubbles generated at the electrode tip (for example, the following). Patent Document 2).

  As shown in FIG. 9, in a main body 203 having an inflow port 201 and an outflow port 202 through which a liquid to be treated flows in and out, a bar-like electrode 204 is provided at the lower part and a plate-like electrode 205 is provided at the upper part. The rod-like electrode 204 is electrically exposed at the tip, and the rod-like electrode 204 and the plate-like electrode 205 are electrically connected to a high-voltage pulse power source 206.

  In such a configuration, the liquid to be processed is introduced into the main body 203 from the inlet 201 and discharged from the outlet 202. At the same time, when a high voltage pulse is applied between the rod-shaped electrode 204 and the plate-like electrode 205 by the high-voltage pulse power source 206, an electric current flows through the liquid to be treated that exists between the rod-like electrode 204 and the plate-like electrode 205, The liquid to be processed evaporates due to Joule heat generated by the electrical resistance of the processing liquid, and a bubble 207 is generated at the tip of the rod-shaped electrode 204. Further, when a high voltage pulse is applied, active oxygen species such as ozone and OH radicals are generated inside and around the bubble 207. The bubble 207 diffuses while moving in the liquid to be treated by its buoyancy.

  Since active oxygen species such as ozone and OH radicals generated inside the bubble 207 have strong oxidizing power, the action eliminates microorganisms contained in the liquid to be treated and decomposes organic substances, which can be used as a water purification device. It can be done.

Japanese Patent Laid-Open No. 2003-62579 JP 2007-207540 A

  By using such a conventional water purification device, it becomes possible to disinfect microorganisms and decompose organic substances contained in the liquid to be treated by utilizing active oxygen species such as ozone and OH radicals.

  However, in the method of introducing bubbles into the liquid to be processed by the bubble generating means, the dielectric breakdown voltage is large when only the liquid to be processed exists between the opposing electrodes and when the bubbles exist between the opposing electrodes. Because it is different, when there is no bubble between the opposing electrodes at the timing of applying a high voltage pulse between the electrodes, it is difficult to perform a stable discharge, and the generation efficiency of active oxygen species such as ozone and OH radicals Had the problem of low.

  In other words, in order to improve the generation efficiency of active oxygen species such as ozone and OH radicals generated by discharge, the probability that bubbles exist between opposing electrodes may be improved. In the main body having a constant flow path cross-sectional area, increasing the bubble generation rate and increasing the bubble existence probability reduces the amount of liquid to be processed and reduces the processing efficiency of the liquid to be processed. Become. Further, even if the opening of the ring-shaped electrode is narrowed to increase the existence probability of bubbles, the amount of liquid to be processed is similarly reduced, and the processing efficiency of the liquid to be processed is reduced.

  On the other hand, in the method of generating bubbles by Joule heat at the tip of the rod-shaped electrode, it is necessary to heat the liquid to be treated to the evaporation temperature, and much of the input electric energy is used to heat the liquid to be treated. In other words, the production efficiency of active oxygen species such as ozone and OH radicals is low.

  Accordingly, the present invention solves the above-described conventional problems, and provides a water purification device capable of improving the generation efficiency of active oxygen species such as ozone and OH radicals without reducing the amount of liquid to be treated. The purpose is to do.

  In order to achieve this object, the present invention holds bubbles floating in the liquid to be processed in the vicinity of the electrode for a certain period of time by the action of the standing wave generated by the ultrasonic vibrator in the liquid to be processed. Thus, a water purifying apparatus characterized by performing stable discharge via air bubbles is achieved, thereby achieving the intended purpose.

  In the present invention, a standing wave is generated in a liquid to be processed by an ultrasonic vibrator provided in the main body. According to the above configuration, the bubbles are trapped at the node of the standing wave generated in the liquid to be processed, so that the bubbles can be held in a specific place in the liquid to be processed. In other words, since bubbles can be held between electrodes that discharge by applying a high voltage pulse, discharge via the bubbles can be reliably performed, and active oxygen species such as ozone and OH radicals can be efficiently generated. The effect of generating can be obtained.

1 is a schematic perspective view showing a water purification apparatus according to Embodiment 1 of the present invention. Same sectional view Same sectional view Schematic enlarged view showing the electrode part Same sectional view Schematic sectional view showing a water purification apparatus according to Embodiment 2 of the present invention. Schematic enlarged view showing the electrode part Schematic showing a conventional water purification device Schematic showing a conventional water purification device

  The water purification apparatus according to claim 1 of the present invention has a configuration in which a standing wave is generated in a liquid to be treated by an ultrasonic vibrator provided in the main body. As a result, the bubbles are trapped in the node portion of the standing wave generated in the liquid to be processed, so that the bubbles can be held in a specific place in the liquid to be processed. In other words, since bubbles can be held between electrodes that discharge by applying a high voltage pulse, discharge via the bubbles can be reliably performed, and active oxygen species such as ozone and OH radicals can be efficiently generated. It produces the effect of generating.

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

(Embodiment 1)
As shown in FIG. 1, the water purification apparatus 1 includes an electrode 5a, an electrode 5b, a bubble generating means 6, an ultrasonic transducer 7a, an inside of a main body 4 having an inlet 2 and an outlet 3 through which a liquid to be treated flows. An ultrasonic transducer 7b is provided.

  The electrodes 5a and 5b are electrically connected to the high-voltage pulse power supply 8, respectively. The bubble generating means 6 is connected to an air introducing means 9 which is a pump by a pipe 10. The ultrasonic transducer 7 a and the ultrasonic transducer 7 b are electrically connected to the high frequency power supply 11.

  The liquid to be processed sucked into the main body 4 from the inlet 2 is discharged via the outlet 3.

  FIG. 2 shows a schematic cross-sectional view of the state in which the liquid to be treated is introduced into the main body 4. As shown in FIG. 2, bubbles 12 are introduced into the liquid to be processed from the tip of the bubble generating means 6.

  When the bubbles 12 are detached from the tip of the bubble generating means 6, they rise in the liquid to be treated.

  FIG. 3 shows a schematic cross-sectional view of the state in which the liquid to be treated is introduced into the main body 4 and the ultrasonic vibrator is applied. When the ultrasonic vibrator 7a and the ultrasonic vibrator 7b are vibrated at a constant frequency in the liquid to be treated, a standing wave 13 is generated in the liquid to be treated.

  FIG. 4 shows a schematic enlarged view of the electrode portion in a state where the standing wave 13 is generated. The electrode tip 14 is exposed at the tips of the electrodes 5a and 5b, and the other portions are covered with an insulating film 15. Further, the bubble 12 is captured at a position corresponding to the node of the standing wave. When a high voltage pulse is applied between the electrode 5a and the electrode 5b in this state, discharge is performed through the bubble 12, and active oxygen species such as ozone and OH radicals are generated inside the bubble 12 and in the peripheral portion. Active oxygen species such as ozone and OH radicals have a strong oxidizing power, so that the action eliminates microorganisms contained in the liquid to be treated and decomposes organic substances, and can be used as a water purification device.

  FIG. 5 shows a schematic cross-sectional view in a state where the action of the ultrasonic transducer is stopped and no standing wave is generated. Due to the action of the high voltage pulse, the bubbles 12 containing ozone and OH radicals diffuse in the liquid to be processed by the buoyancy and the flow of the liquid to be processed.

  In the present embodiment, unlike the conventional water purification apparatus, the bubbles 12 are formed into the electrode 5a and the electrode 5b by the standing wave generated by the ultrasonic vibrator 7a and the ultrasonic vibrator 7b in the liquid to be treated in the main body. Therefore, the discharge through the bubbles 12 can be surely performed. That is, when ultrasonic vibrations having the same frequency and the same phase are generated from the ultrasonic transducers 7a and 7b facing each other in the liquid to be processed, the ultrasonic transducers 7a and 7b are disposed between the ultrasonic transducers 7a and 7b. In this region, places where the vibration displacement is large and places where the vibration displacement is small are alternately formed. That is, a place where vibration displacement is small is a portion corresponding to a node, and nodes are formed at intervals corresponding to ½ of the vibration wavelength.

  In the present embodiment, the frequency of vibration generated from the ultrasonic vibrator 7a and the ultrasonic vibrator 7b is not specified. For example, when ultrasonic vibration of 40 kHz is generated and the liquid to be processed is water, Since the speed of sound is 1500 m / sec, nodes are formed at intervals of about 19 mm. The bubbles floating in the liquid to be treated are left at the position of the node with the least displacement due to the interaction of vibrations of the liquid to be treated around them.

  That is, since the position of the node is determined by the vibration frequency of the ultrasonic transducer 7a and the ultrasonic transducer 7b, if the electrode 5a and the electrode 5b are brought close to each other at an interval of about 19 mm in advance, the electrodes 5a and 5b The bubble 12 can be reliably held at the adjacent site.

  In the present embodiment, the size of the bubble 12 introduced into the liquid to be treated is not particularly limited. However, the diameter may be larger than the distance between the adjacent portions of the electrode 5a and the electrode 5b, and the standing wave Any bubble smaller than the largest bubble that can be trapped may be used. The shorter the distance between the adjacent portions of the electrodes 5a and 5b, the lower the voltage can start the discharge. However, there is a possibility of contact depending on the positional accuracy of the electrodes 5a and 5b. is there. Therefore, if the diameter of the bubble 12 introduced into the liquid to be treated is about 1 mm, the bubble 12 can be held between the electrodes.

  In the present embodiment, the structure of the electrode 5a and the electrode 5b is not specified. However, in order to form a standing wave by ultrasonic vibration in the liquid to be processed, the shape that inhibits transmission of the vibration is used. More specifically, it is better to avoid the electrodes 5a and 5b, and it is better to form the electrodes with a shape having a small cross-sectional area in the portion where the standing wave is formed.

  In the present embodiment, the structure of the electrodes 5a and 5b is a linear electrode with exposed tips. However, in addition to the purpose of not inhibiting the transmission of ultrasonic vibrations, the amount of liquid to be processed is passed. In order to achieve the purpose of increasing the flow rate, it is desirable that the electrode be a linear or needle-like electrode with low flow resistance when the liquid to be processed passes.

  In the present embodiment, the location where the electrodes 5a and 5b are close to each other is not specified, but the number of positions where nodes are formed between the ultrasonic transducer 7a and the ultrasonic transducer 7b. The electrode 5a and the electrode 5b may be set in close proximity to each other.

  In the present embodiment, the structure of the ultrasonic transducer 7a and the ultrasonic transducer 7b is not specified, but in order to limit the position where the bubbles 12 are held in the liquid to be treated, It is better to limit the generation site, and it is desirable that the tip portion has a thin horn shape so that ultrasonic vibrations having directivity facing each other can be generated from the tip portions of the ultrasonic transducer 7a and the ultrasonic transducer 7b.

  In the present embodiment, a high voltage pulse is applied to the electrodes 5a and 5b in accordance with the timing at which the ultrasonic vibrator 7a and the ultrasonic vibrator 7b oscillate. However, the ultrasonic vibrator 7a and the ultrasonic wave are applied. Since the bubble 12 may exist between the electrode 5a and the electrode 5b even when the vibrator 7b does not oscillate, the timing for applying the high voltage pulse is not limited. However, the probability that the bubbles 12 are held between the electrode 5a and the electrode 5b is higher when a high voltage pulse is applied to the electrode 5a and the electrode 5b in accordance with the timing at which the ultrasonic transducer 7a and the ultrasonic transducer 7b oscillate. High efficiency in generating active oxygen species such as ozone and OH radicals.

  In the present embodiment, the ultrasonic transducer 7a and the ultrasonic transducer 7b intermittently oscillate to generate a standing wave intermittently. By applying a high voltage pulse between the electrode 5a and the electrode 5b, active oxygen species such as ozone and OH radicals are generated inside the bubble 12, and therefore, in order to diffuse into the liquid to be treated, a constant is set after discharge. The generation of standing waves was stopped.

(Embodiment 2)
FIG. 6 shows a schematic cross-sectional view of a water purification apparatus including the electrode 16a and the electrode 16b of the second embodiment. The same components as those in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The electrode 16a is an electrode having a plurality of rod-shaped portions, and the electrode 16b is an electrode having a plurality of flat plate portions.

  FIG. 7 shows a schematic enlarged cross-sectional view of the electrode 16a and the electrode 16b.

  The electrode tip 17 is exposed at the tip of the electrode 16a, and the other part is covered with an insulating film 18. A flat plate electrode 19 is provided at the tip of the electrode 16 b, and the other part is covered with an insulating film 18.

  According to this configuration, the structure existing in the region where the standing wave is formed can be reduced as compared with the electrode structure in which a pair of electrodes close to each other as shown in FIG. The obstruction factor when transmitting the vibration from the ultrasonic transducer 7a and the ultrasonic transducer 7b to the liquid to be processed is reduced, and a standing wave can be stably formed. Therefore, the bubbles 12 can be easily captured at the node portion of the standing wave, and stable discharge can be performed. However, in order to compensate for the instability of the discharge due to the distance between the electrodes being separated, the tip portion of the electrode 16b is a flat plate electrode 19.

  As described above, the water purification apparatus of the present invention generates a standing wave in the vicinity of the electrode by an ultrasonic vibrator in the liquid to be processed, thereby making it possible to keep bubbles floating in the liquid to be processed at a specific location. Since stable discharge is performed through bubbles while maintaining the time, active oxygen species such as ozone and OH radicals are generated with high efficiency. Therefore, it is useful as a water purification device that purifies water using ozone and OH radicals for recycling of ultrapure water drainage containing organic substances in electronic parts manufacturing factories, etc., and for decomposition and sterilization of organic substances at water purification plants in waterworks. .

DESCRIPTION OF SYMBOLS 1 Water purification apparatus 2 Inlet 3 Outlet 4 Main body 5a Electrode 5b Electrode 6 Bubble generating means 7a Ultrasonic vibrator 7b Ultrasonic vibrator 8 High pressure pulse power supply 9 Air introducing means 10 Piping 11 High frequency power supply 12 Bubble 13 Standing wave 14 Electrode tip 15 Insulating coating 16a Electrode 16b Electrode 17 Electrode tip 18 Insulating coating 19 Flat plate electrode 101 Inlet 102 Outlet 103 Main body 104 Rod electrode 105 Ring electrode 106 High-pressure pulse power source 107 Bubble generating means 108 Air introducing means 109 Piping 110 Bubble 201 Inlet 202 Outlet 203 Main body 204 Rod electrode 205 Flat electrode 206 High-pressure pulse power supply 207 Bubble

Claims (2)

In the main body having an inlet and an outlet through which the liquid to be treated flows in and out,
Comprising at least a pair of electrodes and a bubble generating part,
A water purification apparatus that generates active oxygen species by applying a voltage between the electrodes, the electrode being disposed near a node of a standing wave generated by an ultrasonic transducer in a liquid to be treated. A water purification device. The water purification apparatus according to claim 1, wherein a standing wave is generated intermittently by the ultrasonic transducer.

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