JP2706982B2 - Ozone sensor and method for detecting ozone concentration in the ozone sensor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone sensor for detecting an ozone concentration in an atmosphere and a method for detecting an ozone concentration in the ozone sensor.

[Prior Art] Conventionally, there are various uses of ozone, and for example, it is known to use it for smelling refrigerators. In this method, a germicidal lamp is provided in a refrigerator, and ozone is generated in the refrigerator by ultraviolet rays emitted from the germicidal lamp. The action of the ozone removes the smell in the refrigerator. In the use of such ozone, it is necessary to control the amount of generated ozone in consideration of the toxicity of ozone. For this reason, it is conceivable to control the amount of generated ozone by detecting the ozone concentration with a sensor. As an ozone sensor required in such a case, for example, there is one shown in "Ozone Technology in Water Treatment" issued by the Secretariat of the Ozone Water Treatment Research Group in 1986, and FIG. FIG. This uses the property of ozone to absorb light of a specific wavelength,
As shown in FIG. 6, a detection side gas cell (101) for flowing a gas to be measured by a pump (not shown) and a reference side gas cell (102) for flowing a reference gas containing no ozone are arranged in parallel. And a light source (1) for emitting light having a wavelength easily absorbed by ozone, and the light from the light source (1) is transmitted to the two cells (101) and (102) through a prism (103) through a shutter (104). 2), the light passes alternately, and the passing light is detected by the light receiving element (4) via the lens (3) and the prism (105).
In the reference-side gas cell (102), almost 100% of the light passes, whereas in the detection-side gas cell (101), light is absorbed by the ozone gas flowing therethrough, and the amount of light passing therethrough depends on the ozone concentration. Therefore, 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 detected voltage difference.

[Problems 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, many components such as a prism, a lens, and a pump are required, which is large and complicated. However, there is a problem that it is expensive and requires a precise assembly because of the optical device.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a small and inexpensive ozone sensor and an ozone concentration detecting method in the ozone sensor.

[Means for Solving the Problems] An ozone sensor according to the present invention includes a roll-shaped reaction test zone impregnated with an ozone-sensitive material that reversibly changes color according to the ozone concentration, and a part of the reaction test zone. A case having a measurement window for contacting ozone and containing the reaction test zone, a light source for emitting light to the reaction test zone, and receiving light from the light source through the reaction test zone; A light receiving element having a resistance value that varies according to the amount of received light, a driving unit that moves the reaction test zone gradually and continuously, and a speed control that changes a driving speed of the driving unit based on the resistance value of the light receiving element. And a circuit.

Also, a roll-shaped reaction test zone impregnated with an ozone-sensitive material that reversibly changes color according to the ozone concentration, a light source that emits light to the reaction test zone, and a light from the light source that emits the reaction test zone. A light receiving element whose resistance value changes according to the amount of received light, a driving means for gradually and continuously moving the reaction test zone, and a driving speed of this driving means to the resistance value of the light receiving element. An ozone sensor having a governing circuit that changes the ozone concentration based on the resistance value of the light receiving means when the ozone concentration does not exceed the discoloration range of the reaction test zone. When the ozone concentration is higher than the discoloration range of the reaction test zone, the ozone concentration is calculated based on the resistance value of the light receiving means and the feed amount of the reaction test zone.

[Action] The roll-shaped reaction test zone impregnated with the ozone-sensitive material according to the present invention is gradually and continuously moved, comes into contact with the gas to be measured through the measurement window, and changes color according to the ozone concentration. Here, the concentration of ozone contained in the atmosphere is measured based on the resistance value that changes according to the amount of light received through the discolored reaction test zone.

Further, the moving speed of the reaction test zone is changed according to the change in the resistance value due to the color change of the ozone-sensitive material.

Further, the ozone concentration is calculated based on the resistance value that changes according to the amount of received light and the amount of feeding of the reaction test zone.

Embodiment FIG. 1 is a schematic front view showing an entire configuration of an ozone sensor according to an embodiment of the present invention, and FIG. 2 is a side view thereof. 1 and 2, (1) is a light emitting element of a light source, (2) is a lead wire thereof, (3) is a lens for focusing light from the light emitting element (1), (4) is a light receiving element, (5) is an indicator cassette containing a roll-shaped reaction test zone in which an aqueous solution of chlorferoin, 5-nitroferroin or the like is impregnated in paper, felt or the like, and (6) is an indicator cassette. (5) a shaft for driving the roller portion; (7) an indicator cassette (5);
And (8) a circuit unit for controlling the rotation speed of the motor (7) according to the resistance value of the light receiving element (4). Further, a calculation and display device (not shown) for displaying the density is separately provided.

FIG. 3 is a circuit diagram of a portion directly related to the light receiving element (4) of the circuit section (8), in which (81) is a DC power supply, and (82) is connected in series with the light receiving element (4). Resistance. The variable resistor (83), the transistor (84), and the motor (7) are connected in series, and the emitter of the transistor (84) is connected between the light receiving element (4) and the resistor (82).

FIG. 4 is a view showing the front and internal structure of the cassette (5), and FIG. 5 is a side view thereof. In FIGS. 4 and 5, (51) is a case, and (52) and (53) are A guide roller (54) is a light receiving window provided in the case (51). The light receiving element (4) is placed here as shown in FIG. Of the transmitted light. (Five
5) is an ozone-sensitive window (measurement window), which is narrower than the width of the reaction test zone (58). Reference numeral (56) denotes a take-up roller for moving the reaction test zone (58). The rotational force of the motor (7) is rotated counterclockwise in FIG. 4 via the shaft (6) in FIG. To wind up, (57)
Is a supply roller around which the reaction test zone (58) is wound.

Ozone-sensitive material such as 5 impregnated in the reaction test zone (58)
-The aqueous solution of nitroferroin exhibits a red color in ordinary air, but oxidizes in the presence of ozone to become pale blue, which is due to the following reaction.

This ozone-sensitive material changes color in accordance with the ozone concentration, and in particular, the amount of light absorption changes within a wavelength range of 400 to 600 nm. Therefore, the detection resistance value of the light receiving element (4) also differs, and the ozone concentration is determined by the detection. It is detected as a difference in resistance value. That is, when ozone is present in the atmosphere, the detection resistance value of the light receiving element (4) becomes lower than that in the clean air, and the ozone is decomposed and returns to red as the ozone is reduced, and the detection resistance value becomes higher. It can detect ozone by increasing or decreasing the value, and can be used repeatedly as a sensor.

The use of 5-nitroferroin as an ozone-sensitive ozone-sensing material is because the discoloration potential of 5-nitroferroin is
1.25 V, and the standard oxidation-reduction potentials of ozone and oxygen are 2.07 V and 1.23 V, respectively.Therefore, 5-nitroferroin has the property of being oxidized by ozone in the atmosphere and not oxidized by oxygen. is there.

However, in general, the redox indicator becomes an ion in water as described above, which is a basic condition for causing a color change. Therefore, when water as a solvent evaporates, a color change reaction due to ozone does not occur. The oxidation reaction with ozone is relatively fast, but the reduction in an atmosphere without ozone is extremely slow.
The present invention employs means for moving the reaction test zone of the indicator portion which has undergone color change once, and constantly detecting the ozone concentration by the reaction test zone of a new portion which has not changed color with ozone.

The operation of the ozone sensor according to this embodiment will be described.
The reaction test zone (58) is discolored by the ozone in the ozone-sensitive window (55) of FIG. 5, and the degree of the discoloration is focused on the lens (3) from the light source (1), and then the reaction test zone (58) is discolored. )
, And is detected by the amount of light that reaches the light receiving element (4). The resistance value of the light receiving element (4) is converted into an ion concentration and displayed. On the other hand, the reaction test zone (58) is gradually and continuously wound by the motor (7) and the take-up roller (56), and a new reaction test zone surface always appears in the ozone-sensitive window (55). This prevents the water from evaporating and causing a malfunction such as discoloration even when ozone is present. In addition, when it comes in contact with ozone having a higher concentration than the discoloration area, the resistance of the light receiving element (4) further decreases, the current to the motor (7) increases by the transistor (84), and the winding roller (56) The rotation speed is increased and the feeding of the reaction test zone is increased. In this case, it is possible to calculate and display a high ozone concentration based on the feeding amount and the resistance value of the light receiving element. The description of the mechanism for displaying the density, 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 the above embodiment, the change in color of the ozone-sensitive material due to ozone is converted into an increase or decrease in light absorption, and the ozone is detected. However, the same can be detected by using reflected light.

[Effects of the Invention] As described above, according to the present invention, a roll-shaped reaction test zone impregnated with an ozone-sensitive material that reversibly changes color according to the ozone concentration, and a part of this reaction test zone A case having a measurement window for contacting ozone and containing the reaction test zone, a light source for emitting light to the reaction test zone, and receiving light from the light source through the reaction test zone; A light receiving element whose resistance value changes according to the received light amount, a driving means for gradually moving the reaction test zone, and a speed control for changing a driving speed of the driving means based on the resistance value of the light receiving element With the circuit, a new reaction test zone is fed out to the measurement window at a speed corresponding to the ozone concentration, and the solvent of the indicator aqueous solution does not evaporate,
A stable measurement is always possible.

Also, a roll-shaped reaction test zone impregnated with an ozone-sensitive material that reversibly changes color according to the ozone concentration, a light source that emits light to the reaction test zone, and a light from the light source that emits the reaction test zone. A light receiving element whose resistance value changes according to the amount of received light, a driving means for gradually and continuously moving the reaction test zone, and a driving speed of this driving means to the resistance value of the light receiving element. An ozone sensor having a governing circuit for changing the ozone concentration based on the resistance value of the light receiving means when the ozone concentration does not exceed the discoloration range of the reaction test zone. When the ozone concentration is higher than the discoloration range of the reaction test zone, the ozone concentration is calculated based on the resistance value of the light receiving means and the feed amount of the reaction test zone. of It is possible to detect the concentration of ozone concentrations.

[Brief description of the drawings]

FIG. 1 is a front view showing the structure 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 a portion relating to a light receiving element and a motor, and FIG. 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 a light receiving element, (6) is a shaft,
(7) is a motor, (8) is a circuit part, (54) is a light receiving window,
(55) is an ozone sensitive window, and (58) is a reaction test zone. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. A roll-shaped reaction test zone impregnated with an ozone-sensitive material that reversibly changes color according to the ozone concentration, and a measurement window for contacting ozone with a part of the reaction test zone, A case for accommodating a reaction test zone, a light source that emits light to the reaction test zone, a light receiving element that receives light from the light source through the reaction test zone, and changes a resistance value according to an amount of received light. An ozone sensor, comprising: driving means for gradually and continuously moving the reaction test zone; and a speed control circuit for changing a driving speed of the driving means based on the resistance value of the light receiving element. . 2. A roll-shaped reaction test zone impregnated with an ozone-sensitive material that reversibly changes color according to the ozone concentration; a light source for emitting light to the reaction test zone; A light-receiving element that receives light via a test band and whose resistance value changes according to the amount of received light; a driving unit that moves the reaction test band gradually and continuously; In the ozone concentration measurement direction in the ozone sensor provided with a speed governing circuit that changes based on the resistance value, when the ozone concentration does not exceed the discoloration range of the reaction test zone, the ozone concentration is determined based on the resistance value of the light receiving means. The ozone concentration is calculated, and when the ozone concentration is equal to or more than the discoloration range of the reaction test zone, the ozone concentration is calculated based on the resistance value of the light receiving means and the feed amount of the reaction test zone. Concentration detection method.