JP2015123398A - Water sterilization device, vertical type multi-layer water sterilization device, and water sterilization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water sterilization device, a vertical type multi-layer water sterilization device, and a water sterilization method, capable of effectively imparting ultrasonic vibration energy to a raw tap water flowing in an aqueduct so as to obtain high sterilization effect on colon bacilli and the like.SOLUTION: An ultrasonic oscillator 9 is disposed on the side of an aqueduct 1 having a polygonal cross section such as a pentagonal or trapezoidal section. A flowing water to be sterilized is supplied from one end to another end of the aqueduct in a full state. A plurality of ultrasonic water treatment parts 20 to 22, 27 and 28 having ultrasonic oscillators on the side of an upright tube having an inner cross section with a polygonal shape disposed in a lateral direction. The ultrasonic water treatment parts 20 to 22, 27 and 28 are series-connected such that the respective one ends of the neighboring upright tubes are communicated with each other. The raw tap water is poured into an ultrasonic water treatment part 20 at the most front end, and a sterilized water is taken in from the ultrasonic water treatment parts 22 and 28 at the most rear end through each ot the upright tubes. Each of the low, medium and high frequencies are repeatedly radiated for 1 to several seconds from each of the oscillators.

Description

  The present invention relates to a water sterilization apparatus and a water sterilization method for sterilizing bacteria contained in water, more specifically, ultrasonic projection of bacteria such as Escherichia coli and protozoa contained in raw water for tap water. The present invention relates to a water sterilization apparatus and a vertical multi-layer water sterilization apparatus that sterilize, and a water sterilization method using these apparatuses.

  As an example of application of an ultrasonic oscillator, the surface of a water tank can be cleaned by applying ultrasonic vibration to the water tank to clean the surface of solid matter immersed in the water tank or by installing an ultrasonic vibrator in the water tank. A spraying device that discharges sprayed water from a nozzle through a nozzle is known, but in addition to this, microscopic protozoa and bacteria in water are killed by ultrasonic vibration in water. For example, in Patent Document 1, ultrasonic vibration is applied to a water tank into which tap water is introduced, and the contact between water molecules and air is increased by dissipating in a mist form from the water surface. A tap water treatment method and a treatment apparatus which are collected in a state are disclosed. According to this, hypochlorous acid contained in tap water after chlorination is removed by self-decomposition by contact with air, and drinking water having no odor of chlorine can be obtained.

  Further, in Patent Document 2, ultrasonic vibration is applied to the water tank to generate bubbles in the water in the water tank, and residual chlorine in the water is included in the bubbles and diffused from the top of the tank, thereby removing the residual chlorine. The bacteria in the water are killed by the mechanical destruction action by ultrasonic vibration. Further, Patent Documents 3 and 4 disclose a water treatment apparatus in which a plurality of ultrasonic oscillators are arranged in a staggered manner in the axial direction in a form that does not oppose each other in the pipe cross section on the outer periphery of a cylindrical pipe having a circular cross section. Has been. The treatment tank is a cylindrical tube so that a large amount of water treatment can be performed without increasing the volume of the treatment tank, and the arrangement of the ultrasonic oscillators is devised. In the literatures 3 and 4, by using a cylindrical tube, a wave generated from the vibration surface of the ultrasonic oscillator interferes with a wave reflected from the inner surface of the cylinder to form a composite wave, and a wall surface serving as a reflection surface is provided. It is said that since it becomes a cylindrical curved surface, an ultrasonic focusing effect can be obtained. In particular, in Patent Document 4, an upstream set of ultrasonic oscillators arranged in a staggered manner in the axial direction is used for low-frequency ultrasonic waves, and a downstream set is used as high-frequency ultrasonic waves. And oxidative sterilization is performed by OH radicals (hydroxy radicals) generated by high-frequency ultrasonic irradiation.

Japanese Laid-Open Patent Publication No. 3-165886 Japanese Unexamined Patent Publication No. 1-231986 Japanese Unexamined Patent Publication No. 2004-202321 Japanese Unexamined Patent Publication No. 2004-202322

  The tap water treatment method of Patent Document 1 removes hypochlorous acid that causes a odor of calcite by exposing it to air by the atomization action of water, and cannot sterilize bacteria such as Escherichia coli. Further, in Patent Document 2, although the sterilization action can be performed in addition to the removal of residual chlorine by the generation of bubbles, since the water surface of the aquarium is exposed to the air, the ultrasonic vibration energy is restricted in the water. In addition, mechanical destruction by ultrasonic vibration is not sufficient, and sterilization of E. coli and the like is difficult. Moreover, the thing described in these literature cannot anticipate an effect with respect to disinfection of the raw water from a lake, a river, etc. in the water purification plant etc. of a tap water production | generation facility.

  As shown in Patent Documents 3 and 4, when an ultrasonic transducer is attached to the side of a water tube having a circular cross section, the vibration wave is reflected back from the tube inner wall on the opposite side (opposite side) in terms of the diameter of the tube. Thus, the oscillation wave and the reflected wave are canceled out and sufficient vibration energy is not generated, and a good sterilization effect cannot be obtained. Further, in order to enhance the sterilizing effect, it is necessary that vibration energy is evenly distributed to the raw water flowing in the water pipe, and the effect of ultrasonic waves is reduced in a state where air stays in the pipe.

  In view of the above problems, the present invention is able to effectively administer ultrasonic vibration energy to raw water for water flowing through a water pipe and obtain a high sterilization effect, a vertical multi-layer water sterilizer, and these It aims at providing the water sterilization method using the apparatus of this.

  The present invention also provides a water sterilization apparatus having a very compact structure and a high sterilization efficiency ultrasonic sterilization treatment section and a vertical multi-layer type in water pipes for raw water or water from rivers, lakes, water storage dams, etc. It aims at providing a water sterilizer.

  For the above purpose, the water sterilizer according to the present invention is provided with an ultrasonic oscillator at the side of a water pipe having a polygonal cross section, and feeds the water to be sterilized in a filled state from one end of the water pipe to the other end. It is what I did.

According to one form of this invention, the said ultrasonic oscillator is provided with two or more spaced apart in the axial direction of the said water pipe, and the installation position of these oscillators has shifted | deviated mutually on the cross section of the said water pipe. It is characterized by that.
By arranging the ultrasonic transducers so as to be shifted in the circumferential direction when viewed on the cross section in this way, it is possible to uniformly apply ultrasonic vibrations to the raw water in the water pipe.

According to another aspect of the present invention, the water pipe is a pipe having a trapezoidal cross section.
By using a trapezoidal tube, interference between the oscillation wave and the reflected wave from the vibrator can be avoided, and sufficient vibration energy can be given to the water.

According to still another aspect of the present invention, the water pipe is a pipe having a pentagonal cross section.
By making the tube having a pentagonal cross section, interference between the oscillating wave and the reflected wave from the vibrator can be avoided, and sufficient vibrational energy can be given to the water.

  Further, according to the present invention, a plurality of ultrasonic water treatment units provided with an ultrasonic oscillator are arranged in the lateral direction on the side of an upright pipe having an inner shape having a polygonal cross section, and one end of each of the adjacent upright pipes is arranged. The ultrasonic water treatment units are connected in series so as to communicate through the water, the raw water for water supply is poured from the ultrasonic water treatment unit on the farthest side, and the ultrasonic waves on the rearmost side are passed through the upright pipes. A vertical multi-layer water sterilization apparatus is provided which takes in sterilized water from a water treatment unit.

According to another aspect of the present invention, the ultrasonic oscillators of the ultrasonic water treatment units are spaced apart from each other in the axial direction of the upright pipe and shifted from each other on the cross section of the upright pipe. It is characterized by being provided.
By arranging the plurality of ultrasonic transducers so as to be separated in the axial direction and shifted in the circumferential direction as viewed on the cross section, the ultrasonic vibration can be uniformly applied to the raw water in the water pipe.

According to another aspect of the present invention, the inner shape of the upright pipe has a trapezoidal cross section.
By using a trapezoidal tube, interference between the oscillation wave and the reflected wave from the vibrator can be avoided, and sufficient vibration energy can be given to the water.

According to another aspect of the present invention, the inner shape of the upright pipe has a pentagonal cross section.
By making the tube having a pentagonal cross section, interference between the oscillating wave and the reflected wave from the vibrator can be avoided, and sufficient vibrational energy can be given to the water.

  In the water sterilization method according to the present invention, a plurality of ultrasonic oscillators are attached to the side of a water pipe having a polygonal cross section, and ultrasonic waves are generated while the oscillation frequency of each ultrasonic oscillator is sequentially changed at predetermined time intervals. Irradiation is performed, and the flowing water to be sterilized is circulated in a full state from one end of the water pipe to the other end.

  According to one embodiment of the water sterilization method of the present invention, the oscillation frequency of each ultrasonic oscillator is sequentially changed to low frequency, medium frequency, and high frequency for 1 second to several seconds.

  According to another aspect of the water sterilization method of the present invention, the oscillation frequency of each of the ultrasonic oscillators is sequentially changed from 28 KHz, 45 KHz, and 100 KHz every 1 to several seconds, and this cycle is repeated. .

  According to the water sterilization apparatus and the water sterilization method of the present invention, the raw water in the water pipe, particularly bacteria such as Escherichia coli contained in the taken-in water can be efficiently applied by applying to the water pipe in the raw water intake section and the raw water treatment section. Can be sterilized.

  Further, in the present invention, the raw water for water supply can be sterilized without resorting to chemical substances such as chlorine, and the influence on the human body and unpleasant taste caused by the chemical substances input for sterilization can be eliminated.

  Furthermore, according to the present invention, a vertical multi-layer water treatment apparatus having a structure in which the ultrasonic treatment section provided in the water pipe is compact and has high sterilization efficiency can be obtained. In addition, the installation area of the ultrasonic transducer can be increased without increasing the size of the whole.

  In addition, according to the present invention, since the water tube has a polygonal cross-sectional shape, a reduction in vibration energy due to interference between the oscillation wave and the reflected wave of the ultrasonic vibrator provided on the side of the water tube is suppressed, which is effective. Sterile action is demonstrated.

  In the water sterilization method according to the present invention, since ultrasonic irradiation is performed by changing the vibration frequency stepwise, fungi and microorganisms concentrated on the node of the amplitude of the vibration wave are increased due to the cavitation effect due to the belly of the amplitude generated immediately after the increase. To do.

It is a schematic side view of the water sterilizer which concerns on Example 1 of this invention applied to the tap water treatment facility. It is a more specific external appearance side view of the water sterilizer shown in FIG. It is a schematic side view of the water sterilizer which concerns on Example 2 of this invention. FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3. It is a schematic cross-sectional view of the water pipe which concerns on the modification of Example 2 shown in FIG. It is a schematic cross-sectional view of a water sterilizer according to Example 3 of the present invention. It is a side view of Example 3 seen from the arrow F of FIG. It is a schematic cross-sectional view of the water pipe which concerns on the modification of Example 3 shown in FIG. 1 is a schematic perspective view of a bowl-shaped multilayer water sterilizer according to an embodiment of the present invention. It is a schematic side view of the vertical multi-layer water sterilizer according to another embodiment of the present invention.

  Next, various embodiments of the present invention will be specifically described with reference to the drawings. In addition, all of the following examples are configured as a tap water treatment facility, specifically, a tap water sterilizer applied to a facility for generating drinking tap water from tap water including a water purification plant or a settling tank. However, the present invention is not necessarily limited to the case where such raw water for water supply is intended, and it is needless to say that the present invention can be applied to other general water sterilization.

  Referring to FIGS. 1 and 2, a water pipe 1 that imparts ultrasonic vibration is supported by a gantry 2 that is suitable for a horizontal state. One end (front end) of the water pipe 1 serving as the sterilization processing unit is connected to the flexible pipe 3, and the front end of the flexible pipe 3 is connected to the raw water intake pipe 5 via the butterfly valve 4. The raw water intake pipe 5 is connected to a raw water storage tank (not shown), and the raw water for water from which dust and dirt are removed in the storage tank is fed to the water pipe 1 according to the present invention via a pump (not shown). The other end (rear end) of the water pipe 1 is sent to the water pipe 8 as tap water that has been sterilized through the water flow detector 6 and the gate valve 7. The water flow detector 6 is provided to confirm that water is flowing from the front end to the rear end of the water pipe 1. In this case, the water pipe 1 has no air space and is filled with running water. Control the flow rate so that is flowing. The flexible tube 3 is for absorbing the amount of misalignment when the water tube 1 installed on the gantry 2 is misaligned with respect to the raw water intake tube 5, and is indispensable for the present invention. It is not a thing.

  As will be described later, the water tube 1 to which the ultrasonic vibrator is attached has an inner shape having a polygonal cross section, and the ultrasonic vibrator 9 is attached to one side portion of the polygon. In this embodiment, seven ultrasonic transducers 9 are attached over a total length of about 310 mm in a state of being aligned in the axial direction as shown in FIG. By the energization of the ultrasonic vibrator 9, ultrasonic vibration energy is generated in the raw water in the water pipe, whereby protozoan fungi (such as Cryptosporidium) and E. coli in the raw water are killed.

  The operation method of the ultrasonic transducer will be described with a specific example. First, after confirming that the water pipe is filled with raw water, the ultrasonic apparatus is turned on. Although the setting of the vibration frequency, the projection time, and the like of the ultrasonic vibrator 9 varies depending on the target sterilization target, the vibration frequency of each vibrator is irradiated in three stages of low frequency, medium frequency, and high frequency. For example, each vibrator is changed to a frequency of 28 KHz, 45 KHz, and 100 KHz every 1 to several seconds, and this cycle is set to be repeated a plurality of times. More specifically, each transducer is first irradiated with an ultrasonic wave with a low frequency of 28 KHz for 1 to 2 seconds, immediately switched to an ultrasonic wave with a medium frequency of 45 KHz, irradiated with 1 to 2 seconds, and further switched to a high frequency of 100 KHz. Irradiate for ~ 2 seconds and repeat this cycle multiple times.

  Underwater cavitation caused by ultrasonic vibrations is concentrated in the part where the standing wave amplitude becomes, but fungi and microorganisms are fixed at the part between the standing wave's belly, In order to kill the microorganisms concentrated in the node part, the frequency is changed so that the next standing wave becomes an antinode in the node part, and the fungus and microorganisms are killed by the cavitation effect. By sequentially changing the frequency from a low frequency to a high frequency, fungi and microorganisms concentrated in the node move to the next belly, so that they are exposed to cavitation and the sterilization action increases. Also in the experiment, it was confirmed that Cryptosporidium bacteria in raw water were killed by repeating such vibration mode twice. In the case of Escherichia coli as well, experiments on vibration modes such as frequency and number of times are performed, the number of dead per unit amount of water is confirmed, and the optimal vibration mode is set.

  In the first embodiment described above, a plurality of ultrasonic transducers arranged in the water pipe are arranged in a line in the direction of the water pipe axis, but in order to enhance the sterilizing effect, a plurality of vibrations are used as shown in FIGS. The children 9 and 10 are preferably arranged in the axial direction so as to be displaced in the circumferential direction of the water tube 1. Explaining this example, ultrasonic transducers 9, 10, 11, 12, and 13 are provided on each side of the water tube 1 having a pentagonal cross section, and these ultrasonic transducers 9 to 13 are provided. Are provided spaced apart from each other at a predetermined interval in the axial direction of the water pipe 1, and the vibrators 9, 10, 11, 12, and 13 are arranged so as to be displaced from each other on the cross section. That is, when viewed from the axial direction of the water tube 1, the vibrators 9 to 13 are displaced in the circumferential direction of the water tube 1. This state is also apparent from FIG. 3, in which the vibrator 10 adjacent to the vibrator 9 on one side 1a of the pentagon is shifted in the axial direction and connected to the side 1a. It is provided above. Similarly, the vibrator 12 on the adjacent side is further shifted in the axial direction from the other vibrator. The same applies to the vibrator 13. By arranging in this way, ultrasonic vibration can be applied evenly over the entire area of the raw water flowing in a full state in the water pipe, and a more reliable and efficient sterilization effect can be obtained.

  By making the inner shape portion of the water tube 1 have a pentagonal cross-sectional shape, ultrasonic waves oscillated from one vibrator 9 on a certain cross-section are generated at opposing inner portions of the same cross-section of the water tube 1. Although reflected, the ratio of the reflected wave 15 (FIG. 4) toward the original vibrator 9 is small, and most of the reflected wave 15 is reflected in an oblique direction with respect to the oscillating wave 16. Since there is less interference, a large decrease in ultrasonic energy is avoided. It is clear from FIG. 4 that the same applies to the vibrators on the other side portions.

  The pentagonal shape of the water tube 1 is preferably a modified pentagon in which the five sides are not parallel to each other as in Example 2 of FIG. 4, but the present invention is not particularly limited to this form, It may be a pentagon in which only two opposing sides are parallel. In particular, when the distance d between the two parallel sides 1a and 1b facing each other is long as shown in FIG. 5 showing a modification of the second embodiment, the path of the oscillation wave is long and one side of the two sides of the parallel is long. The influence of the vibration energy attenuation due to the collision between the oscillation wave 16 of the vibrator 9 on 1a and its reflected wave is small. In this example, the reflected waves by the vibrators 10 and 13 on the other side other than the two parallel sides are reflected in different directions with respect to the oscillation wave as described above, so that cancellation of the vibration wave is avoided.

  FIGS. 6 and 7 are views showing Embodiment 3 of the present invention. In this case, the cross-sectional shape of the water tube 1 is a quadrangle, that is, a trapezoid. A plurality of ultrasonic transducers 9, 10, 11, and 12 are provided with their positions shifted in the direction. The reflected waves of the oscillations oscillated from the vibrators 9 to 12 on each side of the trapezoid are reflected in a direction shifted from the directions of the oscillation waves 16, 17, 18, and 19 of the vibrators 9 to 12, and The attenuation of vibration energy due to the collision with the reflected wave is small. As the trapezoidal shape, in addition to the form in which each side is not parallel as shown in FIG. 6, for example, when the distance d between the two opposite sides 1a and 1b is relatively long as in the modification of FIG. The trapezoid may be such that the two side edges 1a and 1b are parallel to each other. Interference between the oscillation wave and the reflected wave does not occur in the vibrators 10, 12, and 13 on the sides other than the two parallel sides. In this form, the manufacture is relatively easy. In the second and third embodiments shown in FIGS. 4 to 8, the oscillation operation of each vibrator is intermittently performed at a predetermined time interval. As described in the first embodiment, the irradiation mode is also irradiated by changing the vibration frequency in a plurality of stages at intervals of 1 to several seconds, and this vibration mode is continued a plurality of times.

  In each of the above-described embodiments, an example has been described in which one vibrator is disposed on one side portion on the cross section of each axial portion of the water pipe having a polygonal cross section. However, the present invention does not necessarily have such a form. For example, as shown in FIG. 8, two vibrators 10 and 13 may be provided on a certain cross section. When a plurality of vibrators are arranged on a certain cross section, the oscillation waves of the vibrators 10 and 13 on the opposite side portions do not directly enter the vibrators 13 and 10 that face each other. The position is shifted. This avoids damage to the opposing vibrator due to the oscillation wave of one vibrator. As is clear from FIG. 5, the oscillating waves of the vibrators 10 and 13 on the same cross section are arranged so as not to strike the counterpart vibrators 13 and 10.

  In the fourth embodiment of the vertical multilayer water sterilizer shown in FIG. 9, three cylindrical ultrasonic water treatment units 20 to 22 are connected in series via connecting pipes 23 and 24. Each of the ultrasonic water treatment units 20 to 22 is surrounded by a cylindrical outer shell, and inside thereof is a polygonal cross-sectional flow pipe, for example, 5 as shown in FIGS. 4 to 6 and FIG. A square to trapezoidal water pipe is provided, and a plurality of ultrasonic vibrators are provided on the side of the flow pipe so as to be separated from each other in the axial direction of the pipe. In this case as well, the arrangement of the vibrators is sequentially shifted in the circumferential direction as described in FIGS. 3 and 8 in addition to the case where they are arranged in a line in the axial direction at regular intervals as shown in FIG. Provided in the form.

  More specifically, in Example 4 of FIG. 9, the three ultrasonic water treatment units 20 to 22 are provided in a standing state and arranged in parallel in the horizontal direction, and the first ultrasonic water treatment unit 20 to 22 is located on the farthest side. The upper end of one ultrasonic water treatment unit 20 is connected to the raw water introduction pipe 25. The lower end of the first ultrasonic water treatment unit 20 is communicated with the upper end of the adjacent second ultrasonic water treatment unit 21 through the connecting pipe 23, and further, The lower end of the third ultrasonic water treatment unit 22 is further connected to the upper end of the adjacent third ultrasonic water treatment unit 22 by a connecting pipe 24, and the lower end of the third ultrasonic water treatment unit 22 is connected to a water pipe 26 of sterilized water. Is done. This relationship is the same even if the number of tanks (stages) of the ultrasonic water treatment unit is two or four or more. In this way, each ultrasonic water treatment unit is configured in a vertical form, that is, in an upright posture, and is connected in series so that water is sequentially sent from the lower part of the front tank to the upper part of the rear tank. Air is prevented from staying in the pipe of the ultrasonic water treatment section, and the sterilization effect is improved. In addition, by adopting the vertical multi-layer type in this way, the number of ultrasonic transducers installed can be increased while having a very compact structure as a whole, and a greater sterilization effect can be achieved. .

  FIG. 10 is a schematic side view showing a vertical multi-layer water sterilizer according to Embodiment 5 of the present invention. In this example, five ultrasonic water treatment units 20 to 22, 27, and 28 are arranged side by side in a standing state. Each ultrasonic water treatment part has a polygonal cross section as described in FIGS. 3 to 8, for example, a pentagonal or trapezoidal upright pipe, an outer shell surrounding the upright pipe, and the upright pipe It is composed of a plurality of ultrasonic oscillators (ultrasonic vibrators) provided on the side portion of the tube so as to be separated from each other in the axial direction. The arrangement of the ultrasonic oscillators in this case is also substantially the same as that described with reference to FIGS. The difference from the vertical multi-layer water sterilizer of Example 4 is the connection form of each ultrasonic water treatment unit. In the case of Example 5, it is passed through one end of the adjacent ultrasonic water treatment unit, that is, adjacent to each other. The ultrasonic water treatment units 20, 21 and the ultrasonic water treatment units 21, 22 are sequentially connected by the connecting pipes 29, 30, respectively, so that the ultrasonic water treatment on the farthest side is performed. Water to be treated (raw water) introduced into the treatment unit 20 passes through the ultrasonic water treatment units 21, 22, and 27 connected in series, and has been sterilized from the last ultrasonic water treatment unit 28. As taken out. Also in this case, the water to be treated is controlled to flow in a full state in the upright pipe of each ultrasonic water treatment unit. Flow rate detectors 31 and 32 are provided in the raw water introduction pipe 25 connected to the farthest ultrasonic water treatment section 20 and the treated water outflow pipe 33 connected to the rearmost ultrasonic water treatment section, respectively. . In the case of Example 5 as well, although the raw water passes through many ultrasonic water treatment units and is subjected to sterilization treatment, the entire configuration can be configured as a compact facility that does not require an installation place.

  The tap water to be taken into the ultrasonic water treatment section on the farthest side may be directly led from a river, lake, or reservoir dam via a pump, but is preferably stored once in a water purification plant such as a water purification pond or water purification tank. It is preferable to supply water to the ultrasonic water treatment section in a state where impurities such as dust are removed by precipitation. As a result, it is possible to avoid the operation of the ultrasonic water treatment section from being contaminated with impurities and causing a decrease in operation.

  In each of the embodiments described above, the water tube has a pentagonal shape or a trapezoidal cross section. However, in the present invention, other polygonal shapes such as a triangular shape or a deformed shape in which opposing sides are not parallel 6 are used. The cross-sectional shape may be a square shape or a modified octagonal shape. However, for example, a polygon having a large number of corners such as an octagonal shape is close to a circular cross-section tube, so that the pentagonal or trapezoidal shapes described in the embodiments are often used as a more preferable form.

DESCRIPTION OF SYMBOLS 1 Water pipe 2 Base 5 Raw water intake pipe 6 Water flow detection part 8 Water pipe 9, 10, 11, 12, 13 Ultrasonic vibrator 15 Reflected wave 16, 17, 18, 19 Oscillated wave 20, 21, 22, 27, 28 Sonic water treatment unit 23, 24, 29, 30 Connecting pipe 25 Raw water introduction pipe 26 Water pipe 31, 32 Flow rate detector

Claims (11)

  A water sterilizer characterized in that an ultrasonic oscillator is provided on a side portion of a water pipe having a polygonal cross section so that the water to be sterilized is fed in a filled state from one end of the water pipe to the other end.   2. The ultrasonic oscillator according to claim 1, wherein a plurality of the ultrasonic oscillators are provided apart from each other in the axial direction of the water pipe, and installation positions of the oscillators are shifted from each other on a cross section of the water pipe. Water sterilizer.   The water sterilizer according to claim 1 or 2, wherein the water pipe is a pipe having a trapezoidal cross section.   The water sterilizer according to claim 1 or 2, wherein the water pipe is a pipe having a pentagonal cross section.   A plurality of ultrasonic water treatment units provided with an ultrasonic oscillator are arranged in the lateral direction on the side of an upright pipe having an inner shape having a polygonal cross section so that one end of each of the adjacent upright pipes communicates with each other. The ultrasonic water treatment units are connected in series, the raw water for water supply is poured from the ultrasonic water treatment unit on the farthest side, and the sterilized treatment water is supplied from the ultrasonic water treatment unit on the rearmost side through the upright pipes. A vertical multi-layer water sterilizer characterized by taking water.   The ultrasonic oscillator of each of the ultrasonic water treatment units is provided with a plurality of ultrasonic oscillators spaced apart from each other in the axial direction of the upright pipe and shifted from each other on the cross section of the upright pipe. The vertical multi-layer water sterilizer described in 5.   The vertical multi-layer water sterilizer according to claim 5 or 6, wherein the inner shape of the upright pipe has a trapezoidal cross section.   The vertical multi-layer water sterilizer according to claim 5 or 6, wherein the inner shape of the upright pipe has a pentagonal cross section.   A plurality of ultrasonic oscillators are attached to the side of a water pipe having a polygonal cross section, and ultrasonic waves are irradiated while sequentially changing the oscillation frequency of each ultrasonic oscillator at predetermined time intervals. A water sterilization method, characterized in that running water to be sterilized is circulated in a full state toward the end.   The water sterilization method according to claim 9, wherein the oscillation frequency of each of the ultrasonic oscillators is sequentially changed from a low frequency, a medium frequency, and a high frequency every 1 second to several seconds. The water sterilization method according to claim 9 or 10, wherein the oscillation frequency of each of the ultrasonic oscillators is sequentially changed to 28 KHz, 45 KHz, and 100 KHz every 1 to several seconds, and this cycle is repeated.

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