JPH0416749A - Method and apparatus for measuring ozone concentration - Google Patents

Abstract

PURPOSE:To enable constantly stable and highly accurate measurement by detecting predetermined first and second wavelengths of sample transmitted light and by measuring ozone concentration based on a ratio of the detected amounts. CONSTITUTION:Transmission light having a spectrum conforming to an ozone absorption spectrum which has transmitted through a specimen cell 11 housing a sample of ozone water or ozone gas is incident to first and second wavelength detecting units 12, 13 which are provided with interference filters, signal conver sion units and amplifiers 14, 15, 16, 14a, 15a, 16a, respectively, and respective filters 14, 14a detect a first wavelength of a maximum ozone absorption band of the transmission light and a second wavelength different from the first wave length. A ratio of both detection results is calculated by a signal processing unit 17, and ozone concentration free from contamination of the sample cell and a fluctuation in spectrum intensity of the first wavelength due to deteriora tion of a light source is displayed on a display unit 18 so that constantly stable measurement of ozone concentration is possible.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for measuring ozone concentration, and in particular,
New improvements will be made to perform highly accurate measurements in an ozone measurement method that introduces a sample such as ozone water or ozone gas into a sample cell.

[Conventional technology]

There are various methods of measuring ozone concentration of this type that have been used in the past, but the most representative one is the method disclosed in Japanese Patent Application Laid-Open No. 63-218842, shown in FIG. can.

That is, what is indicated by the reference numeral 1 in the figure is an ozone concentration meter, and inside this ozone concentration meter 1, a reference water cell 2 containing reference water and an ozone water cell 3 containing ozone water are provided. ing.

Reference water from a reference water container 4 is introduced into the reference water cell 2 via a first pipe 5, and ozone water from an ozone water container 6 is introduced into the ozone water cell 3 through a second pipe. Piping 7
has been introduced through.

Therefore, by irradiating each cell 2.3 with light and measuring the amount of transmitted light, the ozone concentration in the cell is measured based on the spectral absorption characteristics of ozone, and this measured value is applied to the Lambert-Beer law. I was looking for ozone concentration.

[Means to solve the problem]

The ozone concentration measuring method according to the present invention irradiates a sample with a spectrum matching the absorption spectrum of ozone, measures the amount of transmitted light, and measures the ozone concentration based on the spectral absorption characteristics of ozone. , detecting a first wavelength of the maximum absorption band of the ozone and a second wavelength different from the first wavelength,
In this method, the ozone concentration is measured based on the ratio of the detected amounts of the first wavelength and the second wavelength.

Another invention, an ozone concentration measuring device, irradiates a sample with a spectrum matching the absorption spectrum of ozone from a light source, measures the amount of transmitted light, and measures the ozone concentration based on the spectral absorption characteristics of ozone. In the ozone concentration measuring device according to the present invention, a sample cell that receives light from the light source, a first wavelength detection section and a second wavelength detection section that receive transmitted light from the sample cell, and a first wavelength detection section and a second wavelength detection section that are provided in each of the wavelength detection sections. This configuration includes an interference filter, a signal conversion section, and a signal processing section for processing output signals from each of the wavelength detection sections.

[For production]

In the ozone concentration measuring method and device according to the present invention,
A first wavelength of the maximum absorption band of ozone and a second wavelength different from the first wavelength are detected via a first wavelength detector and a second wavelength detector, and the ratio of the detected amount of each wavelength is determined. ozone concentration can be measured using the signal processing section.

Therefore, by looking at the ratio of the amount of light received at each wavelength, it is possible to cancel contamination of the sample cell, and also to cancel fluctuations in the spectral intensity of the first wavelength due to deterioration of the light source, making it possible to always measure stable and highly accurate ozone concentration. It can be carried out.

〔Example〕

Hereinafter, preferred embodiments of the ozone concentration measuring method and apparatus according to the present invention will be described in detail with reference to the drawings.

It should be noted that the same or equivalent parts as in the conventional example will be described with the same reference numerals.

1 and 2 are for illustrating the ozone concentration measuring method and apparatus according to the present invention. FIG. 1 is a block diagram showing the overall configuration, and the second section is a configuration diagram showing the measurement state.

What is indicated by the reference numeral 1 in the figure is an ozone concentration measuring device, and light having a spectrum matching the absorption spectrum of ozone from a light source 10 of this ozone concentration measuring device 1 is irradiated onto one sample cell 11. , this sample cell 1
1 contains a sample made of ozone water or ozone gas.

The transmitted light that has passed through the sample cell 11 is supplied to a first wavelength detection section 12 and a second wavelength detection section 13, and each of the wavelength detection sections 12.13 includes an interference filter 14.14a and a signal conversion section 15.15a. and electric signal amplifiers 16 and 16a, respectively.

The first wavelength detection unit 12 detects the first wavelength of the maximum absorption band of ozone.
It detects the wavelength, and this first wavelength is 253.7
It is nm. Therefore, out of the light that is not absorbed by the ozonated water, light around 253.7 nm is selectively transmitted by the interference filter 14 and supplied to the signal converter 15 that converts the optical signal into an electrical signal. Here, it is preferable that the interference filter 14 is a bandpass filter that transmits only the wavelength around 253.7 nm, which is the maximum absorption band wavelength of ozone.
The signal converter 15 may be configured by combining a long pass filter, a short bus filter, etc. The signal converter 15 is configured by a photosensor or the like sensitive to the 253.7 n-plane, which is the wavelength of the maximum absorption band of ozone. Furthermore, when the signal converter 15 described above is used, which is sensitive only to 253.7 na+al, it is not necessary to use the interference filter 14.

In addition, since the output of the signal converter 15 is an extremely small signal,
The subsequent electric signal amplifier 16 amplifies the signal to a predetermined level, and converts it to a voltage signal or current signal level required by the signal processing section 17.

Next, the second wavelength detection section 13 detects a second wavelength other than the first wavelength, and detects a wavelength other than the absorption band of ozone. Therefore, while the first wavelength detection section 12 detects ozone absorption, the second wavelength detection section 13 is provided to accurately determine the ozone concentration, and detects deterioration of the light source and absorption by substances other than ozone. The purpose is to detect

Further, the interference filter 14a is preferably a bandpass filter that passes only the second wavelength, but may be configured by combining a longpass filter, a shortpass filter, or the like. The signal converter 15a has a function of converting the amount of light of a wavelength other than the wavelength used in the first wavelength into an electrical signal, and uses a photo sensor or the like. Furthermore, if the signal converter 15a is sensitive only to the selected second wavelength, the interference filter 14a can be omitted.

Furthermore, since the output of the signal converter 15a is a minute signal,
In the subsequent electrical signal amplification section 16a.

The signal is amplified to a predetermined level and converted into a voltage signal or current signal required by the signal processing section 17.

Based on the output signal A of the first wavelength detection section 12 and the output signal B of the second wavelength detection section 13, a signal processing section 17 performs calculations according to Lambert Beer's law, and the results are displayed on the display 1.
It is configured so that it can be displayed or recorded with 8.

The ozone concentration measuring device according to the present invention is configured as described above, and the measuring method thereof will be explained below.

First, the light intensity of the first wavelength emitted from the light source 10 is Pl
, the light intensity of the second wavelength is 22. Since the light emitted from the light source 10 depends on the power supply voltage V of the light source 10,
It is expressed by equations (1) and (2).

p, = t, ・ ■ ・ ・
・ (1) P, = to, ・ ■ ・ ・
・ ・ (2) Next, let the absorption coefficient due to dirt on the sample cell 11 be ρ, and let the intensity of the light of the first wavelength after passing through this dirt be P3, and the intensity of the light of the second wavelength be P. Then, P and P become equations (3) and (4).

P, = ρ・P, = ρ・kl・■ ...(3) P4=ρ
・P,=ρ・k2・■...(4) Therefore, the first
The intensity P of the light of the second wavelength becomes P6 when absorbed by ozone, and the intensity P of the light of the second wavelength becomes P6 when absorbed by water or other substances. Incidentally, the above-mentioned P and P6 are selectively connected to each signal converter 1 by the interference filters 14 and 14a.
515a. Furthermore, if each signal converter 15.15a is provided with one sensitive only to the first wavelength and the second wavelength, the interference filter 14.14a can be omitted, as described above.

According to the above-mentioned conditions, the relationship of equation (5) according to Lambert Beer's law holds between P and P and between P and P6.

I = I ae-”c...(5) Technique: Intensity of light transmitted through solution ■. :Intensity of transmitted light of pure solvent α: Molar extinction coefficient L: Thickness of absorbing material layer C: concentration of absorbing substance Therefore, the following equations (6) and (7) hold true.

P5=P3・e-al“L, CI, e-mloL
,cm,,,,y −(6)P,=P,−e−“
°1°'2 −2− L −c 2 , ρ, 2. v
, , , (7°e Taking the ratio of equation (6) and equation (7), Solving equation (8) for C1 yields equation (9).

In equation (9), k k2. C1, α, , C2, L are things This is a quantity that can be known by measuring it in advance.

Therefore, the ozone concentration C1 can be obtained by measuring P and P6.

Furthermore, Equation (9) does not include ρ and ■, and the ozone concentration CI is not affected by cell contamination or fluctuations in the power supply voltage of the light source.

〔Effect of the invention〕

Since the ozone concentration measuring method and apparatus according to the present invention are configured as described above, the following effects can be obtained.

In other words, by looking at the ratio of the amount of light received at the first wavelength, which is the absorption spectrum band of ozone, and the amount of light received at a second wavelength other than the first wavelength, it is possible to cancel the contamination of the sample cell and to cancel the first wavelength due to deterioration of the light source.
It is possible to cancel fluctuations in wavelength spectrum intensity, etc., and to perform highly accurate measurement of ozone concentration.

In addition, the conventional method required reference water, but the method of the present invention eliminates the need for reference water at all and only requires the introduction of ozone water or ozone gas as a sample, so the overall shape of the device can be changed considerably. It is possible to downsize the device and at the same time achieve cost reduction.

[Brief explanation of drawings]

1 and 2 are for illustrating the ozone concentration measuring method and apparatus according to the present invention. FIG. 1 is a block diagram showing the overall configuration, FIG. 2 is a configuration diagram showing the measurement state, and FIG. 3 is a block diagram showing the overall configuration. 1 is a configuration diagram showing a conventional ozone concentration measuring method. 10 is a light source, 11 is a sample cell, 12 is a first wavelength detection section,
13 is a second wavelength detection section, 15.15a is a signal conversion section, A
, B are output signals, and 17 is a signal processing section. Figure 1 Figure 2 Figure 3 Procedural Amendment Statement August 3, 1990

Claims (2)

[Claims] (1) An ozone concentration measuring method in which the sample (11) is irradiated with a spectrum matching the absorption spectrum of ozone, the amount of transmitted light is measured, and the ozone concentration is measured based on the spectral absorption characteristics of ozone. , detecting a first wavelength of the maximum absorption band of the ozone and a second wavelength different from the first wavelength, and measuring the ozone concentration based on the ratio of the detected amounts of the first wavelength and the second wavelength. A method for measuring ozone concentration characterized by the following. (2) Ozone concentration in which the sample (11) is irradiated with a spectrum matching the absorption spectrum of ozone from the light source (10), the amount of transmitted light is measured, and the ozone concentration is measured based on the spectral absorption characteristics of ozone. In the measurement method, a sample cell (11) receives light from the light source (10), and a first wavelength detection section (12) and a second wavelength detection section (13) that receive transmitted light from the sample cell (11). and a signal converter (1) provided in each of the wavelength detectors (12, 13).
5, 15a), and a signal processing unit (1) for processing the output signals (A, B) from each wavelength detection unit (12, 13).
7), wherein the ozone concentration is measured based on the ratio of the detected amounts of the first wavelength and the second wavelength, which are different from each other from each of the wavelength detection units (12, 13). Concentration measuring device.