JP4581291B2 - Specific resistance adjustment water sterilizer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for sterilizing water with adjusted specific resistance.
[0002]
[Prior art]
Water whose specific resistance is adjusted to a desired value is widely used in production plants for various products.
[0003]
For example, in a can manufacturing plant such as aluminum cans, it is possible to inspect defective products of cans by filling the inside of the can with specific resistance adjustment water and checking the conductivity of the water after filling and the can. ing. The specific resistance adjustment water used in the inspection by the conductivity measurement has a great influence on the inspection due to the fluctuation of the specific resistance value. ing.
[0004]
Conventionally, in order to supply such specific resistance adjustment water, pure water is produced by ion exchange equipment or the like, and the specific resistance is stabilized by dissolving carbonic acid in the pure water ( Japanese Patent Publication No. 63-2231).
[0005]
In recent years, not only such specific resistance adjustment water but also pure water used in various factories has been collected and reused after being used at point of use for the purpose of reducing environmental burden and cost. Yes. Even in facilities using specific resistance adjustment water, used specific resistance adjustment water is collected, and after being adjusted for purity and specific resistance as necessary, circulation reuse is performed.
[0006]
When this specific resistance adjustment water (hereinafter sometimes referred to as “recovered water”) is recovered and reused, when TOC (total organic carbon) components are mixed, microorganisms are particularly likely to propagate in the circulating water system. In some cases, the value of the product may be reduced or the product may be defective due to microorganisms adhering to the product. For this reason, the recovered water is sterilized or sterilized using an ultraviolet sterilizer, a hot water sterilizer, an electron beam sterilizer, an ultrafiltration membrane sterilizer, or the like.
[0007]
[Problems to be solved by the invention]
Among the above-mentioned conventional sterilization or sterilization apparatuses, only the hot water sterilization apparatus can sterilize or sterilize microorganisms generated in the circulation pipes downstream of the sterilization or sterilization apparatus. If resistance adjustment water is collected and hot water is circulated in the circulation system, plastic piping, ion exchange resin, ion exchange membrane, etc., which are inferior in heat resistance, may be deteriorated. In addition, if a part that may be deteriorated is replaced with a heat-resistant part, the equipment cost becomes high. For this reason, application of a hot water sterilizer is not preferable in a normal recovered water circulation system.
[0008]
Further, in the collection and circulation system of specific resistance adjustment water, it is desired to suppress the growth of microorganisms in the system without affecting the specific resistance value of the recovered water.
[0009]
The present invention provides a specific resistance adjustment water sterilizer that can effectively sterilize the system without affecting the specific resistance value of the recovered water in the recovery and circulation system of the specific resistance adjustment water. Objective.
[0010]
[Means for Solving the Problems]
The specific resistance adjustment water sterilization apparatus of the present invention is an apparatus for sterilizing water whose specific resistance value is adjusted, and the water whose specific resistance value has been adjusted is recovered water from the can inspection process, and the can inspection process An ozone decomposing apparatus for decomposing ozone in recovered water ( treated water ) from the ultraviolet ray, ultraviolet sterilizing means for sterilizing the treated water ozone-decomposed by the ozone decomposing apparatus by irradiating with ultraviolet light, and the ultraviolet light An ozone addition means for adding ozone to the water to be treated sterilized by the sterilization means, and a means for circulating the water added with ozone by the ozone addition means to the can inspection process .
[0011]
In the present invention, the ultraviolet sterilization means sterilizes microorganisms or spore bacteria in the system or reduces their propagation ability without affecting the specific resistance value of the recovered water. The ozone addition means dissolves ozone in a part or all of the recovered water irradiated with ultraviolet rays, and suppresses the growth of microorganisms in the subsequent circulation piping and use points by the sterilizing power of ozone.
[0012]
By the way, when ozone-containing water is irradiated with ultraviolet rays, a remarkably strong oxidizing action is generated, and organic substances in the water are decomposed and ionized to affect the specific resistance value. For this reason, in the present invention, the ozone addition means is provided in the subsequent stage of the ultraviolet sterilization means, and the ozone decomposition means is provided in the previous stage of the ultraviolet sterilization means.
[0013]
The specific resistance adjustment water sterilizer according to claim 2 further comprises an ozone concentration measuring means for measuring an ozone concentration of water circulated in a can inspection process, and the ozone adding means based on the ozone concentration obtained by the ozone concentration measuring means. And a control means for controlling the amount of ozone added to the water, and it is possible to reliably sterilize by dissolving ozone at a predetermined concentration in the recovered water.
[0014]
In the specific resistance adjustment water sterilizer of claim 3, the ozone addition means is an ozone addition means for intermittently adding ozone to the water to be treated, and an intermittent addition time setting device for setting the intermittent addition time is provided. By adjusting the time interval of intermittent ozone addition, efficient sterilization can be performed while reducing the amount of ozone used.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 is a system diagram showing an embodiment of a specific resistance adjustment water sterilizer according to the present invention.
[0017]
The specific resistance-adjusted water sterilizer of FIG. 1 treats the recovered water from the can inspection process 10 by passing the water through the ozone decomposing apparatus 1, the particulate removing apparatus 2 and the ultraviolet sterilizing apparatus 3 in order with the pump P, and sterilizing the ultraviolet light. A part of the water is passed through the ozone dissolving device 4, and the remaining part is joined with the water from the ozone dissolving device 4 and circulated to the can inspection process 10. In this embodiment, the ozone concentration meter 5 measures the ozone concentration of the water circulated in the can inspection process 10 and controls the ozone dissolution amount of the ozone dissolving device 4 based on the measurement result. Has been.
[0018]
As the ozonolysis apparatus 1, an activated carbon tower, a reducing agent addition, etc. can be used. The ozone decomposition device 1 decomposes and removes ozone in the recovered water, and ozone is prevented from being decomposed and ionized by being irradiated with ultraviolet rays by the ultraviolet sterilization device 3 to affect the specific resistance value. That is, as shown in FIG. 1, when the recovered water is passed through the ultraviolet sterilizer 3 and the ozone dissolving device 4 and sterilized and then circulated to the can inspection process 10, the recovered water from the can inspection process 10 The ozone added by the ozone dissolving device 4 is included. Therefore, in the apparatus of FIG. 1, ozone in the recovered water is decomposed and removed by the ozone decomposition apparatus 1.
[0019]
In particular, when an activated carbon tower is used as the ozone decomposing apparatus 1, the TOC component in the recovered water is also decomposed and removed, and the TOC component is decomposed and ionized by being irradiated with ultraviolet rays by the ultraviolet sterilizing apparatus 3. Can also be prevented.
[0020]
As the particulate removal device 2, various filters, an ultrafiltration membrane separation device, and the like can be used. By this fine particle removing device 2, the fine particles flowing out from the ozone decomposition device 1 such as the can inspection process 10 or the activated carbon tower can be removed to increase the purity of the recovered water.
[0021]
The effluent from the fine particle removing device 2 is then sterilized by ultraviolet irradiation in the ultraviolet sterilizing device 3. In the apparatus shown in FIG. 1, in the recovered water circulation system, microorganisms in the water are repeatedly irradiated with ultraviolet rays by the ultraviolet sterilizer 3 so that they die or at least lose their growth ability.
[0022]
Part of the effluent from the UV sterilizer 3 is introduced into the ozone dissolver 4, and the remainder is directly circulated to the can inspection process 10.
[0023]
By adding ozone with the ozone lysis device 4, it is possible to sterilize resistant bacteria remaining in the water even after the ultraviolet sterilization with the ultraviolet sterilization device 3, and the growth of microorganisms in the circulation pipe after the ozone lysis device 4 Can also be suppressed. Further, in the sealed can inspection process 10, sterilization in the manufacturing environment can be performed by ozone vaporized from the specific resistance adjustment water.
[0024]
The total amount of the effluent water from the ultraviolet sterilizer 3 may be introduced into the ozone dissolver 4, but as shown in FIG. You may make it make it merge with the remainder of the effluent of the ultraviolet sterilizer 3 after addition. If it does in this way, the ozone dissolution apparatus 4 can be reduced in size.
[0025]
In the apparatus of FIG. 1, the ozone concentration in the circulating water is measured by an ozone concentration meter 5 provided at the inlet of the can inspection process 10 of the recovered water circulation system, and the ozone addition amount in the ozone dissolving device 4 is determined based on this measured value. By controlling, the ozone addition amount is prevented from being excessive or insufficient, and sufficient ozone is added for sterilization without causing an adverse effect on the can inspection process 10 due to the excessive amount of ozone, thereby performing stable and reliable sterilization.
[0026]
In order to control the amount of ozone added in the ozone dissolving device 4 based on the measured value of the ozone concentration meter 5, for example, the amount of oxygen supplied to the ozone generator of the ozone dissolving device 4 is adjusted. That is, when the measured value of the ozone concentration meter 5 is less than the set value, the amount of ozone generation is increased by increasing the oxygen supply amount to the ozone generator, and the measured value of the ozone concentration meter 5 is larger than the set value. In some cases, the amount of oxygen supplied to the ozone generator is reduced to reduce the amount of ozone generated, thereby adjusting the amount of ozone added. In order to increase or decrease the amount of oxygen supplied to the ozone generator, for example, a compressor (air compressor) that supplies air to the ozone generator is inverter-controlled, or a control valve provided in the oxygen supply line to the ozone generator ( Adjust the opening of a valve that can be adjusted from 0 to 100%.
[0027]
In the present invention, it is preferable that the ozone dissolving device 4 is capable of adding ozone intermittently and arbitrarily controlling the time interval of the intermittent addition of ozone.
[0028]
That is, the water temperature is high in the summer and the microorganisms are easy to grow, but the water temperature is low in the winter and the microorganisms are difficult to grow. In order to cope with such changes in the growth tendency of microorganisms due to the external environment, ozone addition is intermittently performed rather than management based on ozone concentration, and the addition time (ON time) and addition stop time (OFF time) are set. Set in advance according to the season, for example, set a longer ON time or a shorter OFF time in the summer, and set a shorter ON time or a longer OFF time in the winter. It is preferable to intermittently add ozone. In this way, the ozone addition amount can be easily adjusted with an ozone dissolving apparatus that can set the time interval for intermittent addition of ozone.
[0029]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
[0030]
Example 1
The sterilization effect according to the present invention was examined in a sterilization circulation system in which the recovered water from the can inspection process 10 shown in FIG. 1 was processed at a flow rate of 10 m ³ / hr.
[0031]
The ozonolysis apparatus, fine particle removal apparatus, ultraviolet sterilization apparatus, and ozone dissolution apparatus used are as follows.
Ozonizer: activated carbon tower water flow SV = 50 hr ⁻¹
Particulate removal device: Safety filter (pore size 1μm)
Ultraviolet sterilizer: A device that irradiates ultraviolet rays having a wavelength of 253.7 nm. Residence time: 6 seconds. Ozone dissolver: An ozone dissolver that intermittently adds ozone.
25% of the effluent from the UV sterilizer was introduced into the ozone dissolver, and the remainder was directly circulated into the can inspection process. In the ozone dissolution apparatus, the ON time is 30 minutes and the OFF time is 60 minutes in summer, the ON time is 10 minutes and OFF time is 120 minutes in winter, and the measured value of the ozone concentration meter is 0.5 to 1.0 ppm in summer. In winter, the amount of air supplied to the ozone generator was controlled to be 0.1 to 0.5 ppm.
[0033]
As a result, the number of viable bacteria in the circulatory system could be suppressed to 10 / L or less throughout the year.
[0034]
Moreover, there was no change in the specific resistance value of 1.0 MΩ · cm of the recovered water from the can inspection process, and it could be circulated to the can inspection process without affecting the specific resistance value by sterilization.
[0035]
Comparative Example 1
In Example 1, except that the activated carbon tower was not provided, sterilization circulation was performed in the same manner. As a result, ozone contained in the recovered water was decomposed and ionized by the ultraviolet sterilizer, so that the specific resistance value was 0.5. It changed to ˜1.0 MΩ · cm. The number of viable bacteria in the circulatory system was 10 / L or less, and the bactericidal effect was the same as in Example 1.
[0036]
Comparative Example 2
In Example 1, when the sterilization circulation was performed in the same manner except that the ozone dissolution apparatus was not provided, there was almost no change in the specific resistance of the recovered water, but the microorganisms grew in the circulation pipe after the ultraviolet sterilization apparatus. to become a viable cell number 10 ³ / L or more, it was not possible to obtain a satisfactory sterilizing effect.
[0037]
Comparative Example 3
Where except that no provided a UV sterilizer in Example 1 was subjected to sterilizing circulation in the same manner, the number of viable bacteria was a change and 10 to 10 ^three / L.
[0038]
【The invention's effect】
As described above in detail, according to the specific resistance adjusted water sterilization apparatus of the present invention, the specific resistance adjusted water can be effectively sterilized in the recovery and circulation system without affecting the specific resistance value of the recovered water. can do.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of a specific resistance adjustment water sterilizer according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ozone decomposition apparatus 2 Fine particle removal apparatus 3 Ultraviolet sterilization apparatus 4 Ozone dissolution apparatus 5 Ozone concentration meter 10 Can inspection process

Claims (5)

A device for sterilizing water with a specific resistance value adjusted,
The water whose specific resistance value is adjusted is recovered water from the can inspection process,
An ozonolysis device for decomposing ozone in the recovered water ( treated water ) from the can inspection process ;
UV sterilization means for sterilizing the water to be treated which has been subjected to ozonolysis with the ozonolysis apparatus by irradiating with ultraviolet rays;
Ozone addition means for adding ozone to the water to be sterilized by the ultraviolet sterilization means;
And a means for circulating water added with ozone by the ozone adding means to a can inspection process . The control for controlling the amount of ozone added in the ozone adding means according to claim 1, wherein the ozone concentration measuring means for measuring the ozone concentration of water circulated in the can inspection process and the ozone concentration obtained by the ozone concentration measuring means are controlled. And a specific resistance adjustment water sterilizer.   3. The ozone addition means according to claim 1, wherein the ozone addition means is ozone addition means for intermittently adding ozone to the water to be treated, and includes an intermittent addition time setting device for setting the intermittent addition time. Specific resistance adjustment water sterilizer. The specific resistance-adjusted water sterilizer according to any one of claims 1 to 3, wherein the ozonolysis apparatus is an activated carbon tower. 5. The water to be treated sterilized by the ultraviolet sterilization unit according to claim 1, wherein a part of the water to be treated is introduced into the ozone addition unit and the remaining part is directly circulated to the can inspection process. Specific resistance adjustment water sterilizer.

Images