JP4536501B2 - Method and apparatus for measuring ozone concentration in ozone water - Google Patents

Description

  The present invention relates to a method and an apparatus for measuring ozone concentration in ozone water by using visible light, and more particularly to a method and apparatus for measuring ozone concentration using white light obtained by synthesizing three primary colors of light as visible light. .

  Conventionally, the ozone concentration in ozone water is, for example, an ozone concentration meter (for example, a light source that emits ultraviolet light, a flexible tube that transmits ultraviolet light, and a transmitted light detector that receives ultraviolet light that has passed through the tube) (See Patent Document 1) and the like, which is performed by using ultraviolet rays having a wavelength band of about 240 to 270 nm.

In addition, a method of measuring ozone concentration using a colorimetric method was also known, but this was done by adding a reagent to ozone water and using the color change such as decolorization and color development of the reagent due to the oxidizing power of ozone, etc. (For example, refer to Patent Document 2).
JP 2000-72498 A JP-A-5-52389

  However, when ultraviolet rays are used, the intensity of the transmitted light that has passed through the ozone water to be measured has been detected by the ultraviolet sensor. However, this ultraviolet sensor is expensive, and the measurement is expensive. It was too much.

  In addition, when a conventional colorimetric method is used, a reagent that changes based on the action of ozone is used to measure changes in the color of the reagent, but this is an indirect measurement method. It was also necessary to prepare specific reagents.

  Therefore, the present invention provides an inexpensive and accurate ozone concentration measuring method and measuring apparatus that can directly measure the ozone concentration without using a special reagent, using a photoelectric sensor that is less expensive than an ultraviolet sensor. The purpose is to provide.

  As a result of intensive studies, the present inventors have found that ozone concentration can be measured by measuring reflected or transmitted light of ozone water by irradiation with visible light in ozone water with few impurities dissolved in pure water. The present invention has been completed.

  That is, the method for measuring the ozone concentration in ozone water according to the present invention includes a visible light irradiation step of irradiating ozone water composed of pure water in which ozone is dissolved from a light projecting portion of a photoelectric sensor, and a visible light irradiation step. A light detection step of detecting reflected light or transmitted light of the irradiated visible light by ozone water by a light receiving portion of the photoelectric sensor, and a concentration calculation step of calculating ozone concentration in the ozone water based on the amount of received light detected by the photoelectric sensor; , Characterized by having.

  Moreover, the ozone concentration measuring apparatus in the ozone water according to the present invention includes a light projecting unit capable of irradiating the ozone water to be measured with visible light and reflection of the visible light irradiated from the light projecting unit by the ozone water to be measured. Calculates the ozone concentration in the ozone water based on the photoelectric sensor consisting of the light receiving unit that detects light or transmitted light, the ozone water storage tank that can store the ozone water to be measured, and the amount of received light detected by the light receiving unit And an arithmetic unit for performing the processing.

  In this specification, the photoelectric sensor is a sensor that can detect the presence or state of an object by a change in the amount of light, and converts received light into an electrical signal corresponding to the amount of light (brightness). .

  According to the ozone concentration measuring method and measuring apparatus of the present invention, the parts used in the measuring apparatus can be easily obtained, and the ozone concentration measuring apparatus is provided at a low cost because it is cheaper than the parts used conventionally. In addition, since the measurement itself can be performed at a low cost, it is extremely effective for reducing the cost.

  Also, the colorimetric method is different from the indirect method using conventional reagents, and it is performed by sensing the change in ozone water itself due to the change in concentration. can do.

First, the ozone concentration measuring apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of an ozone concentration measuring apparatus according to the present invention.

  The ozone concentration measuring apparatus 1 according to the present invention includes a photoelectric sensor unit 2, an ozone water storage unit 3, and a calculation unit 4.

  The photoelectric sensor unit 2 used in the present invention receives the light from the light projecting unit 2a having a light emitting element for irradiating the detection light toward the detection region and the light from the detection region, and changes the light amount according to the received light amount. And a light receiving portion 2b that converts the light into the light receiving portion 2b.

  As the photoelectric sensor unit 2, a photoelectric sensor of a transmission type, a reflection type, or the like can be used. Among them, a reflection type as shown in FIG. 1 is preferable in measuring ozone water.

  In the reflection type photoelectric sensor unit 2, a light projecting unit 2a and a light receiving unit 2b are usually integrally formed. FIG. 2 is a diagram showing a schematic configuration of the ozone concentration measuring apparatus of the present invention using the transmission type photoelectric sensor unit 2. Here, the light projecting unit 2a and the light receiving unit 2b are arranged at positions facing each other across the ozone water to be measured.

  The light projecting unit 2a in such a photoelectric sensor 2 is not particularly limited as long as it has a light source capable of irradiating visible light such as an LED and an LD (laser diode), but is not limited to ozone water. It is preferable to use an LED from the viewpoint that it can efficiently irradiate visible light having a wavelength, can irradiate by combining various wavelengths, and is suitable for measurement of ozone concentration.

  The visible light irradiated here is visible light including at least three types of wavelengths including wavelengths of the red region, the green region, and the blue region, and is called visible light. Is preferred.

  At this time, the red region is light having a wavelength of 630 to 720 nm, the green region is light having a wavelength of 500 to 555 nm, the blue region is light having a wavelength of 465 to 490 nm, and peaks at 665 nm, 520 nm, and 465 nm, respectively. It is particularly preferable that the visible light has a higher measurement accuracy. The irradiated visible light is reflected, transmitted, and absorbed by the ozone water to be measured, and is converted into specific reflected light and transmitted light depending on the ozone concentration of the ozone water.

  In addition, this light projecting unit may irradiate the ozone water to be irradiated from any of the upper, lower, left and right sides, but is preferably installed so that visible light can be irradiated from below, vertically upward and downward Is particularly preferred. Thus, when visible light irradiation is performed from the lower side, there is an advantage that it is hardly affected by bubbles.

  The light receiving unit 2b includes a light receiving element such as a phototransistor, a photodiode, or a PSD (position detecting photodiode) as a light receiving element, which converts it into an electric signal according to the amount of light received. The amount of received light is detected based on this amount of electrical signal.

  In addition, this photoelectric sensor can be classified according to its configuration, and may be any type such as an amplifier built-in type, an amplifier separation type, and a fiber type. In this, the sensor unit can be separated from the detection unit. It is preferable to be an amplifier separation type that makes it possible to approach the ozone water pipe.

    A configuration example of the photoelectric sensor unit 2 is shown in FIG. 3, and the photoelectric sensor unit 2 includes a light source box 110 and a lens / element box 100. In the light source box 110, a red light source 111, a blue light source 112, a green light source 113, and a special half mirror 114 are arranged as shown in the figure, and white light from three color light sources of the red light source 111, the green light source 113, and the blue light source 112 is disposed. Can be irradiated.

    The white light emitted from the light source box 110 enters the lens / element box 100 connected by the optical fiber 6, and the incident white light travels toward the projector lens 101, and the white light that has passed through the projector lens 101 Reflected by the ozone water storage unit 3, the reflected light passes through the light receiving lens 102 and is received by the light receiving element 120. According to the amount of light received by the light receiving element 120, a result of calculation processing by the calculation unit 4 described later is obtained.

  Moreover, the ozone water accommodating part 3 used by this invention should just accommodate the ozone water of a measuring object, and is manufactured with the light transmissive container. The ozone water storage unit 3 can be configured as a part of a flow path of ozone water in an environment where ozone water is used, in addition to a cell type that collects and stores ozone water as a sample.

  Here, examples of the light-transmitting material used for the ozone water storage unit 3 include quartz, glass, sapphire, a transparent fluororesin, and the like, and the refractive index is small and measurement is not hindered. Therefore, quartz or sapphire is preferable.

  Moreover, when using a reflection type as the photoelectric sensor part 2, it is preferable that the light projection part 2a is arrange | positioned in the extension direction of the long axis of the ozone water accommodating part 3, and also the ozone water accommodating part at this time 3 is preferably tubular (columnar). When the ozone water storage part 3 is tubular, the ozone water storage part 3 having a diameter of 2 to 3 cm and a length of 15 to 30 cm is preferable. Here, the size of the ozone water storage unit 3 can be adjusted according to the ozone concentration of the ozone water to be measured. For example, when measuring ozone water having an ozone concentration of 15 to 45 ppm, the ozone water storage unit 3 Is preferably 15 to 30 cm long, and more preferably 7 to 10 cm long when measuring 40 to 70 ppm of ozone water.

  Next, the calculation unit 4 used in the present invention measures an electrical signal converted based on the light received by the light receiving unit 2b of the photoelectric sensor unit 2, and the calculation unit 4 includes a microprocessor, a memory, and the like. Is configured to digitize the amount of light received by the photoelectric sensor unit 2 and store the calculation result in a memory as necessary, or read out the data stored in advance and perform comparison. The received light amount measured by the calculation unit 4 has a display unit for displaying the measured value, and analyzes the relationship between the ozone concentration and the measured value based on the received light amount sensed by the photoelectric sensor unit 2 in advance for calibration. If a line is created, the ozone concentration can be obtained immediately from the displayed measurement value.

  Furthermore, if the calculation unit 4 is configured to perform the process of calculating the ozone concentration by comparing the measurement value of the received light amount with the calibration curve data, the ozone concentration in the finally measured ozone water is displayed on the display unit. You can also.

  Next, the method for measuring the concentration of ozone water according to the present invention will be described.

  The visible light irradiation process of the present invention is to irradiate the ozone water, which is a measurement object, from the light projecting unit 2a of the photoelectric sensor unit 2, and the reflected light corresponding to the ozone concentration by the irradiation of the visible light. And transmitted light will appear.

  Here, it is preferable that the visible light used for irradiation has at least three types of visible light including wavelengths of the red region, the green region, and the blue region. At this time, the red region is light having a wavelength of 630 to 720 nm, the green region is light having a wavelength of 500 to 555 nm, and the blue region is light having a wavelength having a peak at 455 to 490 nm. In each region, visible light having peaks at 665 nm, 520 nm, and 465 nm, respectively, is preferable in terms of high measurement accuracy. The irradiated visible light is reflected, transmitted, and absorbed by ozone water according to its wavelength, and converted into specific reflected light and transmitted light depending on its ozone concentration.

  Further, the light detection step of the present invention is a step of detecting light when the light irradiated to the ozone water by the visible light irradiation step is reflected or transmitted by the ozone water by the light receiving unit 2b of the photoelectric sensor unit 2, Here, as described above, reflected light or transmitted light specific to the ozone concentration, which appears by irradiation with visible light, is detected.

  The light receiving unit used for this detection is composed of a light receiving element such as a phototransistor, a photodiode, or a PSD (position detecting photodiode), and this detects the amount of light received.

  Since the reflected light or transmitted light detected here depends on the ozone concentration of ozone water, the amount of received light varies depending on the ozone concentration, and the measured value of the amount of received light detected in this step is Used in the concentration calculation step.

  The amount of received light can be measured by storing ozone water in a storage tank separate from the environment in which it is used, but ozone in ozone water decomposes over time and the ozone concentration gradually decreases. Therefore, it is preferable to measure by providing an ozone water storage tank under the usage environment of ozone water.

  For example, the ozone water produced and introduced by the ozone water production apparatus is accommodated in the ozone water accommodating portion 3, and if this accommodating portion is provided in the middle of the ozone water piping, the sample water can be simply flowed. Measurement can be performed without sampling. In addition to being able to accurately check the ozone concentration of ozone water that is actually used, this is a method for measuring the ozone concentration, which was impossible due to chemical changes in ozone in systems using conventional reagents. It is.

  In addition, in order to measure the ozone concentration in ozone water, the water in which ozone is dissolved needs to be pure water. Pure water is obtained by removing impurities in water, and since substances that cause noise in the measurement using the photoelectric sensor unit 2 are previously removed as in the present invention, measurement with visible light is possible. . In other words, ozone water using pure water reduces measurement errors due to impurities, and measurement is possible only after optical properties based on ozone concentration can be measured with high accuracy.

  In addition, it is known that the amount of dissolved ozone can be increased if carbon dioxide is dissolved in pure water in advance to produce ozone water. In the present invention, the wavelength band of visible light is increased. Therefore, the ozone concentration measurement is hardly influenced by the dissolution of carbon dioxide having a strong absorption band in the infrared region. According to this measurement method, the noise due to the carbonic acid dissolution is extremely small and can be ignored.

  Here, looking at the absorption spectrum of gas components dissolved in ozone water, oxygen is a Schumann-Lunge continuous absorption band at 130 to 180 nm, ozone is a Hartley absorption band at 220 to 300 nm, a Chapius absorption band at 450 to 850 nm, and dioxide. Carbon has a typical absorption band different from infrared absorption around 4240 nm.

  However, although the absorption intensity of the chapius absorption band of ozone is weaker than that of other absorption bands, it can be sufficiently measured by reducing noise as much as possible using pure water as in the present invention.

  The pure water used here preferably has a specific resistance value in the range of 1.0 to 18.3 MΩ · cm, since it can be measured with high accuracy, and 10.0 to 18.3 MΩ · cm. It is especially preferable that it is ultrapure water of cm.

  Furthermore, when carbon dioxide is dissolved in the pure water used here, the pH of the water in which carbon dioxide is dissolved is preferably 4 to 5, and the water temperature during measurement is preferably 15 to 25 ° C. These conditions are preferable conditions for enabling measurement with visible light with high accuracy.

  The concentration calculation process of the present invention calculates the ozone concentration of ozone water as the measurement object based on the amount of light received detected in the light detection process. The concentration can be calculated by analyzing the relationship between the ozone concentration and the measured value based on the amount of received light in advance and creating a calibration curve, and the ozone concentration can be calculated immediately from the measured value. The ozone concentration result can be obtained immediately by performing arithmetic processing by the above.

  The present invention will be described below with reference to examples.

Example 1
The ozone concentration measuring apparatus used here has an apparatus configuration as shown in FIG. 4. First, the colorimetric tube 20 in which an ozone water container having a flat bottom surface is provided, and the colorimetric tube 20. The colorimetric tube 20 is composed of a sensor 21 attached to the lower part and a measuring instrument 22 having a calculation unit for converting the signal obtained here into an ozone concentration measuring device instruction value. The apparatus 23 is connected to the ozone water introduction pipe 24 and further includes an ozone water drain pipe 25. As shown in FIG. 3, the sensor 21 has a lens / element box and a light source box connected by an optical fiber.

The ozone water produced by the ozone water production device 23 is continuously injected into the ozone water storage part (tube length: 250 mm) in the colorimetric tube 20 through the ozone water introduction tube 24, and directly from the ozone water drain tube 25. It was made to drain. Therefore, the ozone concentration can be measured while the ozone water actually used for measurement is kept flowing.
The sensor 21 uses an optical sensor manufactured by Keyence Corporation, and the signal obtained by the light receiving element in the sensor 21 is subjected to calculation processing by a calculation unit in the measuring instrument 22, and the ozone concentration measuring device shown on the vertical axis in FIG. The indicated value (1000 max) was calculated.

(Comparative Example 1)
In order to see the correlation between the indicated value measured in Example 1 and the ozone concentration in the ozone water, the dissolved ozone concentration meter (model: OM-101) manufactured by Aplix Co., Ltd. and the former Kos Co. It was measured using an inline type dissolved ozone monitor (model: OZ-96i) manufactured by HORIBA Advanced Techno.
The measurement was performed by branching a pipe from the ozone water introduction pipe 24 of Example 1 and connecting to the devices of the two companies.

  The measurement results are shown in FIG. The measurement results of the dissolved ozone concentration meter manufactured by Aplix Corporation and the measurement results of Example 1 are compared with (1) A company (Aplix Corporation) (□: measurement point) and (2) Kos Co., Ltd. This is shown by the comparison between HORIBA Advanced Techno) and Example 1 (♦ mark: measurement point). In all the comparison results, a good linear relationship was obtained in the ozone concentration range of 10 to 40 ppm.

  In addition, when the length of the ozone water storage part in the colorimetric tube 22 in Example 1 was measured by the same method as Example 1 using the thing of 8 cm, it was compared with Comparative Example 1 in the range of ozone concentration 40-70 ppm. A similar linear relationship was obtained.

It is the figure which showed the example of a structure example of the ozone concentration measuring apparatus of this invention. It is the figure which showed another structural example outline of the ozone concentration measuring apparatus of this invention. It is the figure which showed the structural example of the photoelectric sensor used by this invention. It is the figure which showed the structural example of the ozone concentration measuring apparatus used in the Example. It is a correlation diagram of ozone concentration and the instruction | indication value of the ozone concentration measuring apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ozone concentration measuring device, 2 ... Photoelectric sensor part, 2a ... Light projection part, 2b ... Light receiving part, 3 ... Ozone water accommodating part, 4 ... Calculation part, 5 ... White light path, 6 ... Optical fiber, 20 ... Colorimetric Pipe, 21 ... Sensor, 22 ... Measuring instrument, 23 ... Ozone water production device, 24 ... Ozone water introduction pipe, 25 ... Ozone water drain pipe, 100 ... Lens / element box, 101 ... Projection lens, 102 ... Light receiving lens, DESCRIPTION OF SYMBOLS 120 ... Light receiving element, 110 ... Light source box, 111 ... Red light source, 112 ... Blue light source, 113 ... Green light source, 114 ... Special half mirror

Claims (5)

Each of the red region 630 to 720 nm , the green region 500 to 555 nm, and the blue region 465 to 490 nm covering most of the range from the light projecting portion of the photoelectric sensor to the Chapius absorption band in ozone water composed of pure water in which ozone is dissolved. A visible light irradiation step of irradiating visible light including at least three types of wavelengths including
A light detection step of detecting reflected light or transmitted light of the visible light irradiated by the ozone water by the visible light irradiation step by a light receiving unit of the photoelectric sensor;
A concentration calculating step of calculating an ozone concentration in the ozone water based on the amount of received light including the at least three types of wavelengths detected by the photoelectric sensor;
A method for measuring ozone concentration in ozone water. 2. The ozone concentration measuring method according to claim 1 , wherein the visible light is white light composed of red light having a peak at 665 nm, green light having a peak at 520 nm, and blue light having a peak at 465 nm. The method for measuring ozone concentration according to claim 1 or 2, wherein the specific resistance value of the pure water is 10.0 to 18.3 MΩ · cm. Visible light comprising at least three wavelengths including wavelengths of red region 630 to 720 nm , green region 500 to 555 nm, and blue region 465 to 490 nm covering most of the range of the Chapius absorption band in the ozone water to be measured. A photoelectric sensor comprising a light projecting unit capable of irradiating light and a light receiving unit for detecting reflected light or transmitted light of the measurement target ozone water of visible light irradiated from the light projecting unit;
An ozone water storage tank for storing pure water in which ozone is dissolved as the ozone water to be measured;
A calculation unit that calculates an ozone concentration in the ozone water based on an amount of received light including the at least three types of wavelengths detected by the light receiving unit;
A device for measuring the ozone concentration in ozone water. The light projecting unit is composed of an LED capable of emitting red light having a peak at 665 nm, an LED capable of emitting green light having a peak at 520 nm, and an LED capable of emitting blue light having a peak at 465 nm. The ozone concentration measuring device according to claim 4, wherein

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