JPH02304351A - Ozone sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ozone sensor that detects ozone concentration in an atmosphere.

[Prior Art] Ozone has been used in various ways, for example, it is known to be used to eliminate odors from refrigerators. This involves installing a germicidal lamp inside the refrigerator, which uses the ultraviolet rays it emits to generate ozone inside the refrigerator, and this ozone removes odors inside the refrigerator. In such use of ozone, it is necessary to control the amount of ozone generated in consideration of its toxicity, and for this purpose, it is possible to detect the ozone concentration with a sensor and control the amount of ozone generated. The ozone senna required in such cases is:
For example, there is one shown in "Ozone Technology in Water Treatment" published by the Secretariat of the Ozone Water Treatment Study Group in 1986, and FIG. 6 is a block diagram showing the device. This utilizes the property of ozone to absorb light of a specific wavelength, and as shown in Figure 6, there is a gas cell (101) on the detection side that flows the gas to be measured using a pump (not shown), and a gas cell (101) on the detection side that flows the gas to be measured using a pump (not shown). Reference-side gas cells (102) through which a non-containing reference gas flows are arranged in parallel, and a light source (1) that emits light with a wavelength that is easily absorbed by ozone is provided, and the light from this light source (1) is used to Prism (103) in cells (101) and (102)
The light passes through the shutter (104) alternately by operating the shutter (104), and the passing light is detected by the light receiving element (4) via the lens (3) and the prism. In the reference side gas cell (102), almost LOCI% of light passes through, whereas in the detection side gas cell (102), light passes through the detection side gas cell (102).
In 1), light is absorbed by the ozone gas flowing through it, and the amount of light passing through varies depending on the ozone concentration.
The detection voltage of the light receiving element (4) is also different between the reference side and the detection side, and the ozone concentration is detected as the difference between the detection voltages.

[Problem to be solved by the invention] Since the conventional ozone sensor is configured as described above, in addition to the detection side and reference side gas cells, the prism, lens,
There are problems in that it requires many components such as a pump and is large, complex, and expensive, and because it is an optical device, it must be assembled precisely.

This invention was made to solve these problems, and its purpose is to obtain a small and inexpensive ozone sensor.

[Means for Solving the Problems] The ozone sensor according to the present invention brings a gas to be measured into contact with a part of a roll-shaped reaction test strip impregnated with an ozone-sensitive material that reversibly changes color depending on the ozone concentration. a light receiving device that detects a discolored reaction test zone in a measurement window; a driving device that gradually moves the reaction test zone; and a speed regulating circuit that changes the speed of this driving device in accordance with the output of the light receiving device. This is something I prepared for.

[Function] The roll-shaped reaction test strip impregnated with the ozone-sensitive material of the present invention gradually moves and comes into contact with the gas to be measured through the measurement window, changing color depending on the ozone concentration. Here, the amount of light transmitted through the discolored reaction test zone is detected to measure the ozone concentration contained in the atmosphere. Further, by changing the moving speed of the reaction test zone according to the color change of the ozone-sensitive material, the ozone concentration can be detected from the color change and the moving speed.

[Embodiment] FIG. 1 is a schematic front view showing the overall configuration of an ozone sensor according to an embodiment of the present invention, and FIG. 2 is a side view thereof. In Figures 1 and 2, (1) is the light emitting element of the light source, (2) is its lead wire, and (3) is the light emitting element (1).
(4) is a light-receiving element, (5) is a lens that focuses light from
) is an indicator cassette containing a roll-shaped reaction test strip made by soaking paper, felt, etc. in an aqueous solution of chlorferroin, 5-nitropherroin, etc.; (6) is an indicator cassette ( 5) is a shaft that drives a portion of the roller, (7) is a motor that rotates a portion of the roller of the indicator cassette (5), and (8) is a motor that controls the rotational speed of the motor (7) according to the resistance value of the light receiving element (4). This is the circuit section that controls it. Further, a calculation and display device (not shown) for displaying the concentration is separately provided.

Figure 3 is a circuit diagram of the part of the circuit section (8) directly related to the light receiving element (4). In the figure, (81) is a DC power supply, and (82) is connected in series with the light receiving element (4). It is a resistance. Variable resistor (83), transistor (84).

The motors (7) are connected in series, and the emitter of the transistor (84) is connected between the light receiving element (4) and the resistor (82).

Figure 4 is a diagram showing the front and internal structure of the cassette (5), and Figure 5 is a side view thereof. In Figures 4 and 5, (51) is the case, (52) and (53) are The guide roller (54) is a light receiving window provided in the case (5I), and as shown in Fig. 1, the light receiving element (4) is placed here and the light source (1) above is placed under the reaction test zone (58). Receives transmitted light. (55) is an ozone-sensitive window (measuring window), which has an opening narrower than the width of the reaction test zone (58). (56) is a winding roller for moving the reaction test strip (58), and the rotational force of the motor (7) is applied to the fourth roller through the shaft (6).
In the figure, it rotates counterclockwise to wind up the reaction test strip (58), and (57) is a supply roller around which the reaction test strip (58) is wound.

Ozone-sensitive material to be impregnated into the reaction test zone (58), for example 5
- An aqueous solution of nitropherroin exhibits a red color in ordinary air, but in the presence of ozone, it is oxidized and becomes pale blue, and this is due to the following reaction.

This ozone-sensitive material changes color depending on the ozone concentration, and the amount of light absorbed changes, especially within the wavelength range of 400 to 800 cm, so the detection resistance value of the light receiving element (4) also differs, and the ozone concentration changes depending on the ozone concentration. Detected as a difference in detection resistance values. In other words, if ozone exists in the atmosphere, the detection resistance value of the light receiving element (4) will be lower than in clean air, and as the ozone decomposes and decreases, the color will return to red and the detection resistance value will become higher. Ozone can be detected by increasing and decreasing this resistance value, and it can be used repeatedly as a sensor.

The reason why 5-nitropherroin is used as an ozone-sensitive material for detecting ozone is that the discoloration potential of 5-nitropherroin is 1.
．． 25V, and the standard redox potentials of ozone and oxygen are 2.07V and 1.23V, respectively, so 5-nitropherroin has the property of being oxidized by ozone in the atmosphere but not by oxygen. It is.

However, in general, the basic condition for redox indicators to change color is to form ions in water, as described above, so once the water, which is the solvent, evaporates, the color change reaction due to ozone does not occur. In addition, although the oxidation reaction due to ozone is relatively fast, the reduction in an atmosphere without ozone is extremely slow. Therefore, in this invention, the reaction test zone of the indicator part that has changed color is moved, and the reaction test is performed on a new part that has not changed color due to ozone. A method is used to constantly detect ozone concentration using a band.

To explain the operation of the ozone sensor according to this embodiment, ozone causes the reaction test zone (58) to change color at the ozone-sensitive window (55) in FIG. ), the reaction test zone (
58) and reaches the light receiving element (4). The resistance value of this light receiving element (4) is converted into ion concentration and displayed. On the other hand, the reaction test strip (58) is gradually wound up by the motor (7) and the winding roller (56), and a new surface of the reaction test strip always appears at the ozone-sensitive window (55), so water is removed by drying. evaporate,
Malfunctions such as discoloration not occurring even in the presence of ozone are prevented. In addition, when it comes into contact with ozone at a high concentration above the discoloration range, the resistance of the light receiving element (4) further decreases, the transistor (84) increases the current to the motor (7), and the winding roller (56) Although the rotation speed is increased and the reaction test band is fed more, it is possible to detect and display a high ozone concentration by calculating the band feeding amount and the resistance value of the light receiving element in this case. Note that the explanation of the density display, the mechanism for displaying the ozone concentration from the paper feed amount and the resistance value of the light receiving element, and the calculation method will be omitted.

In addition, in the above example, ozone was detected by converting the color change of the ozone-sensitive material caused by ozone into an increase or decrease in light absorption17, but it is also possible to detect ozone in the same way using reflected light. .

[Effects of the Invention] As explained above, according to the present invention, a reaction test strip impregnated with an aqueous indicator solution made of an ozone-sensitive material is rolled up and housed in a cassette, and a new reaction test strip is gradually added during measurement. Since the ozone sensor is fed out from the roller, the solvent of the aqueous indicator solution is prevented from evaporating, and an ozone sensor that can always perform stable measurements can be obtained.

[Brief explanation of drawings]

FIG. 1 is a front view showing the configuration of an ozone sensor according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, FIG. 3 is a circuit diagram of the portion related to the light receiving element and motor, and FIG. 4 is a cassette 5 is a side view of the cassette, and FIG. 6 is a configuration diagram of a conventional ozone sensor. In the figure, (4) is the light receiving element, (6) is the shaft, (
7) is the motor, (8) is the circuit section, (54) is the light receiving window, (
55) is an ozone-sensitive window, and (58) is a reaction test zone. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent: Patent Attorney Muneji Sasaki 4: Light Receiving Poison Fang 5: 4 Shower Cassette Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A roll-shaped reaction test strip impregnated with an ozone-sensitive material that reversibly changes color depending on the ozone concentration, a measurement window that contacts a part of this reaction test strip with the gas to be measured, and a It includes a light receiving device for detecting discoloration of the reaction test zone, a driving device for gradually moving the reaction test zone, and a speed regulating circuit for changing the driving speed of the driving device based on the output of the light receiving device. An ozone sensor characterized by: