JP2531278B2 - Ozone concentration measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ozone concentration measuring device having a simple structure and being highly portable.

[Prior Art] Conventionally, an ozone concentration measuring device utilizing the absorption of ultraviolet light by ozone is known.

FIG. 5 shows a typical example of this type of device. Two quartz glass tubes for measuring the ozone concentration and a zero gas containing no ozone are passed through a rotary valve 50.
It is sent to 51, 52. A low-pressure mercury lamp 53 is arranged between the tubes 51 and 52, and the ultraviolet light thereof passes through the tubes 51 and 52 separately and enters the ultraviolet sensors 54 and 55, respectively.
The output signals of the ultraviolet light sensors 54 and 55 are differentially amplified by the operational amplifier 56 via separate preamplifiers (not shown), and the output signal difference between the sensors 54 and 55 is output to the indicator 57.

In this device, first, the rotary valve 50 is switched to flow zero gas through both tubes 51 and 52, and the indicator output at this time is 0.
The operational amplifier 56 or the above preamplifier is adjusted so that the measurement gas is passed through the quartz glass tube 51, and the zero gas is passed through the quartz glass tube 52 to detect the difference between them. It compensates for various fluctuations and changes in sensitivity over time.

[Problems to be Solved by the Invention] Although the above-mentioned ozone concentration measuring device is used for various purposes, it has a complicated configuration and operation and requires zero gas in particular, so that it can be downsized or used for portable purposes. It wasn't easy to do.

However, there is a demand for an ozone concentration measuring device that is smaller in size, more portable, and more highly accurate than conventional ones for industrial use, development use, and the like.

The present invention has been made in view of such problems,
It is a problem to be solved to provide a compact, highly accurate and highly portable ozone concentration measuring device.

[Means for Solving the Problems] The ozone concentration measuring apparatus of the present invention includes a closed case having an ultraviolet light emission window and an ultraviolet light shielding film in a portion other than the window, and the ultraviolet light enclosed in the closed case. A lamp that radiates ultraviolet light for measurement from a light radiation window, and is radiated from the lamp while being enclosed in the hermetically sealed case located at a position other than the portion between the ultraviolet light radiation window and the lamp, and in the case A correction light-receiving portion that photoelectrically converts the correction ultraviolet light that is reflected and incident, and the lamp and the ultraviolet light emission window and the correction light that are located outside the portion between the ultraviolet light emission window and the lamp A shielding plate which is separated from the light receiving portion and blocks the ultraviolet light which is incident on the correction light receiving portion from the lamp and the ultraviolet light which is transmitted through the ultraviolet light emission window and is incident on the correction light receiving portion. With the light emitting device A measurement light-receiving unit that photoelectrically converts the measurement ultraviolet light incident from the lamp via a measurement space where ozone can exist; and a correction light-receiving unit when ozone does not exist in the measurement space, A circuit unit that corrects the ratio of the measurement values output from the correction light receiving unit and the measurement light receiving unit when measuring the ozone concentration of the measured space based on the ratio of the initial values output from the measurement light receiving unit. An ozone concentration measuring device comprising:

The space to be measured may be, for example, a space inside a glass tube connected to a pipe through which ozone gas flows, or a room where the ozone concentration should be measured. The phrase "when ozone is absent" described above allows the presence of a negligible amount of ozone, for example, in measurement.

[Operation] Part of the ultraviolet light emitted from the lamp is incident on the measuring light receiving portion, and the other part is incident on the correcting light receiving portion. First, each light receiving part receives the ultraviolet light that is not modulated by ozone and photoelectrically converts it, and each output signal (initial value) M1, C1 of each light receiving part
Alternatively, their ratio (M1 / C1) is stored in the initial ratio storage unit. Next, a part of the ultraviolet light output from the lamp is modulated by the ozone gas and then enters the measurement light receiving portion, and at the same time, another part of the ultraviolet light is not modulated by the ozone gas and enters the correction light receiving portion. Each light receiving unit transmits the output signals (measurement values) M2 and C2 to the measurement ratio correction calculation unit. The measurement ratio correction calculation unit compensates for the change in the light amount of the lamp by dividing the ratio of measured values (M2 / C2) by the ratio of initial values (M1 / C1).

The lamp and the correction light receiving part are housed in a common closed case having an ultraviolet light emission window, and the correction light receiving part directly receives only a certain proportion of the ultraviolet light output from the lamp and emits light. We monitor changes in quantity.

Further, in the present invention, a shielding plate is provided between the correction light receiving portion for signal correction and the lamp and the ultraviolet light emitting window, and the shielding plate is an ultraviolet light which enters the case from the outside through the ultraviolet light emitting window. The strong ultraviolet light emitted from the lamp and the lamp is prevented from directly entering the light receiving portion for correction, and the ultraviolet light emitted from the lamp and reflected by the case is input to the light receiving portion for correction.

[Example] An example of the ozone concentration measuring apparatus of the present invention will be described with reference to the drawings.

As shown in FIG. 1, this ozone concentration measuring device includes a light emitting device 1 and a light receiving device for measurement which are arranged on both sides of an axis of a quartz glass tube 5 having openings at both ends to which ozone-containing air is fed. Part 2, microcomputer 3 for signal processing, and microcomputer 3
Of the quartz glass tube 5, the light emitting device 1, the measurement light receiving portion 2, the microcomputer 3, and the indicator 4 are fixed on an insulating substrate (not shown).

As shown in FIGS. 2 and 3, the light emitting device 1 includes a cylindrical wall portion (a closed case in the present invention) 11 made of quartz glass having an opening at one end and an opening end of the cylindrical wall portion 11. It has a ceramic stem (a closed case according to the invention) 12 that stops to form a closed space inside, and a terminal 13 projects from the stem 12. A part of the peripheral wall of the cylindrical wall portion 11 serves as an ultraviolet light emission window, and an aluminum vapor-deposited film or a black coating film (the ultraviolet light in the present invention for shielding ultraviolet light is formed on the outer surface of the other part of the cylindrical wall 11). A light shielding film) is applied. On the upper surface of the stem 12 surrounded by the cylindrical wall portion 11, a lamp 14, a shielding plate 16, and a correction light receiving portion 15 are arranged in this order from the ultraviolet light emission window side.
Are arranged, and the electrode portions (not shown) of the lamp 14 and the correction light receiving portion 15 are connected to the terminal 13. A shield plate 16 arranged in the center of the upper surface of the stem 12 shields the ultraviolet light from directly entering from the outside through the ultraviolet light emission window or from the lamp 14 to the correction light receiving portion 15. A gap d is left between the uppermost end of the shield plate 16 and the inner surface of the upper end of the cylindrical wall portion 11 as shown in FIG.
The light is reflected by the inner surface of the upper end of 11 and can enter the correction light receiving portion 15 via the gap d. A small low-pressure mercury lamp is used as the lamp 14, and a semiconductor type ultraviolet light sensor is used as the correction light receiving unit 15 and the measurement light receiving unit 2. An inert gas is enclosed in the closed case.

Although not shown, the microcomputer 3 is a light receiving unit for correction.
15 and a preamplifier that amplifies the output signal of the measurement light receiving section 2 are built in the input interface,
This input interface is CP like a normal microcomputer.
It is connected to the U, RAM, ROM and output interface via a bus. The output interface is connected to a three-digit decimal display indicator 4. This microcomputer 3
In addition to constituting the initial ratio storage unit and the measurement ratio correction calculation unit in the present invention, the application of the power supply voltage to the lamp 14, the correction light receiving unit 15, the measurement light receiving unit 2 and the indicator 4 is also controlled.

The quartz glass tube 5 is an opening at both ends having the space to be measured in the present invention inside, and is provided in the middle of the ozone containing air vent tube 10 via a rubber tube (not shown).

Next, the operation of this ozone concentration measuring apparatus will be described with reference to the flow chart of the microcomputer 3 shown in FIG.

First, the ozone concentration measuring apparatus is configured such that before the quartz glass tube 5 is connected to the ventilation tube 10, that is, in a state where ozone is not present in the quartz glass tube 5, the correction light receiving unit 15 is used.
The sensitivity ratio (ratio of initial values) between the measuring light receiving unit 2 and the measuring light receiving unit 2 is measured and stored.

That is, when the microcomputer 3 is started without connecting the quartz glass tube 5 to the ventilation tube 10, the microcomputer 3 causes the lamp 14,
Correction light receiving unit 15, measurement light receiving unit 2 and indicator 4
The power supply voltage is applied to these to start them, and at the same time, they are initialized internally (S10), and after a predetermined time has passed for stabilization of the lamp output (S12), the initial ratio setting provided in the microcomputer 3 is set. It is detected whether or not a button (not shown) is pressed (S14). This initial ratio setting button is for detecting and storing the initial ratio M1 / C1. When the pressing is detected, the output signal (initial value) C1 of the light receiving unit for correction C1
Also, the output signal (initial value) M1 of the measurement light receiving unit 2 is received (S16), the ratio M1 / C1 of these initial values is calculated and written in the built-in nonvolatile memory (not shown) (S18), and the process proceeds to S20. .
If the pressure is not detected in S14, the process directly proceeds to S20. As a result, both the light receiving parts 15 in a state where the ultraviolet light is not absorbed by ozone and the incident light on the measurement light receiving part 2 is not dimmed,
A sensitivity ratio of 2 is stored.

Since the subsequent routine is for ozone concentration measurement, the quartz glass tube 5 is connected to the ventilation tube 10 and the ozone-containing air flows through the quartz glass tube 5.

In S20, the output signal (measurement value) C2 of the correction light-receiving unit 15 and the output signal (measurement value) M2 of the measurement light-receiving unit 2 are received, and the ratio M2 / C2 of these measurement values is divided by the ratio M1 / C1 of the initial value. Then, the correction signal S is calculated (C22). Then, the calculated correction signal S is multiplied by a predetermined constant K to calculate the ozone concentration D and displayed on the indicator 4 (S24). The constant K is stored in advance in the ROM as a table, and is extracted from the table according to the value of the correction signal S and used.

In this way, it is possible to compensate for fluctuations in the power supply voltage and fluctuations in the lamp output due to changes over time between the measurement points of the initial signals C1 and M1 and the measurement points of the measurement signals C2 and M2.

Next, the process waits for a predetermined time (S26), returns to S14, and repeats the routine.

 Hereinafter, other features of this embodiment will be described.

In this embodiment, since the quartz glass tube 5, the light emitting device 1, the measurement light receiving portion 2, the microcomputer 3 and the indicator 4 are fixed on the same insulating substrate (not shown), their relative displacements are It is convenient to move while preventing. Since the lamp 14 and the light receiving portion 15 for correction are provided on the stem 12, the size can be reduced and the power supply terminal and the like can be shared. Further, the arrival rate of the ultraviolet light to the correction light receiving portion 15 does not change due to stains on the glass surface of each part, and the shielding plate 16 allows the ultraviolet light that becomes noise from the outside to reach the correction light receiving portion 15. Prevent.

[Effects of the Invention] As described above, the ozone concentration measuring apparatus of the present invention is
Since the ultraviolet light emitting lamp and the correction light receiving part are enclosed in a sealed case, and the output ratio of the correction light receiving part and the measurement light receiving part in the absence of ozone gas is stored and used for correction,
The device can be made compact and movable, and the ozone gas concentration can be measured with high accuracy.

Further, according to the present invention, since the window incident ultraviolet light modulated by the measurement space is not incident on the correction light receiving section, the non-modulated signal light that is not modulated by the measurement space entering the correction light receiving section and the measurement light receiving section are received. It is possible to increase the ratio with the modulated signal light that is modulated by the space to be measured and is incident on the section, and it is possible to improve the SN ratio of the signal output from the circuit section. Further, since the strong direct-injection ultraviolet light does not directly enter the correction light-receiving portion from the lamp which is very close to the correction light-receiving portion, saturation of the correction light-receiving portion can be prevented. Since these effects can be realized with a simple structure in which a shielding plate is provided, the overall structure can be made compact and simple.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the ozone concentration measuring device of the present invention, FIG. 2 is a schematic perspective view showing an embodiment of a light emitting device, and FIG. 3 is a sectional view of the light emitting device of FIG. FIG. 4 is a flowchart of the microcomputer 3. FIG. 5 is a block diagram of a conventional ozone concentration measuring device. 1 …… Light emitting device 2 …… Measuring light receiving part 3 …… Microcomputer (circuit part) 4 …… Indicator 5 …… Quartz glass tube 15 …… Correction light receiving part

Claims (1)

(57) [Claims] 1. A closed case having an ultraviolet light emission window and an ultraviolet light shielding film in a portion other than the window, and a lamp which is enclosed in the closed case and emits ultraviolet light for measurement from the ultraviolet light emission window. And photoelectrically converting the ultraviolet light for correction which is located in a portion other than the portion between the ultraviolet light emitting window and the lamp and is enclosed in the hermetically sealed case, is emitted from the lamp, is reflected by the case, and is incident. A correction light-receiving part, which is located other than a portion between the ultraviolet light emission window and the lamp, and is separated from the lamp and the ultraviolet light emission window and the correction light-receiving part. A light emitting device having a shielding plate for blocking the ultraviolet light incident on the correction light receiving portion and the ultraviolet light passing through the ultraviolet light emission window and entering the correction light receiving portion, and a measurement space in which ozone may exist. Via LA Measuring photo-electric part for photoelectrically converting the measuring ultraviolet light incident from the pump, and to the ratio of the initial value output from the correcting photo-receiving part and the measuring photo-receiving part when ozone is not present in the measured space. An ozone concentration measuring device comprising: a correction light receiving unit and a circuit unit that corrects a ratio of measurement values output from the measurement light receiving unit based on the measurement of the ozone concentration in the measured space.