JPH07104283B2 - Air pollutant automatic measuring machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air pollutant automatic measuring device for automatically measuring the concentration of pollutants in the atmosphere.

[0002]

2. Description of the Related Art Conventionally, for example, a measuring instrument for automatically measuring the concentration of pollutants such as nitrogen dioxide in the atmosphere has been put into a predetermined container, There is a method in which contaminated air is sent into this container by an air pump so that the absorbing liquid absorbs the contaminants, and the concentration of the absorbing liquid that changes due to the contaminants is electrically measured. . In this case, the absorbing liquid in the container in which the measuring absorbing liquid is placed is sent from the storage tank using a liquid sending pump or the like every predetermined time, and is discharged to the waste liquid tank every predetermined time. And
The concentration of the measured absorption liquid is measured to detect the contamination concentration.

By using such a measuring device, the concentration of pollutants in the atmosphere can be automatically measured. For example, the measuring instrument is installed at a point where air pollution is considered to be relatively advanced. If so, it is possible to know whether or not the air pollution state at the measurement point exceeds the environmental standard.

[0004]

However, such a conventionally used measuring machine has the disadvantages that it is very complicated in structure, large in size, and expensive, and therefore it cannot be installed in many places. It was Therefore, in the past, if you wanted to know the pollution status of an entire area, you would use a computer to interpolate the data from a small number of measuring stations installed in this area to obtain the pollution status of the entire area. However, such computer processing is very expensive and time-consuming.

Further, such a measuring machine has a disadvantage that the accuracy of measured data is poor. That is, for example, as described above, in the case of a measuring machine that performs the work of adsorbing contaminants by sending air to the absorbing liquid side with an air pump, the amount of air fed and the amount of absorbing liquid must be constant. Although accurate measurement was not possible, it was difficult to accurately control the air flow rate and liquid volume. Therefore, the conventional measurement data has a very large error, and in the worst case, an error of 10% or more may occur.

An object of the present invention is to provide an air pollutant automatic measuring machine which can perform accurate measurement with a device having a simple structure.

[0007]

According to the present invention, as shown in FIG. 1, for example, a first container 1 for containing a liquid whose state is changed by absorption of air pollutants and a permeation of outside air without permeating the liquid. A water-repellent filter 11 for detachably attaching the air pollutant absorbing portion 10 into which the liquid supplied from the first container 1 can be filled, and the air pollutant absorbing portion 1
The measuring means 13 and 14 for measuring the state of the liquid in 0 and the liquid filled in the air pollutant absorbing portion 10
And an exhausting means 22 for exhausting the filter 11 to adjust the mounting position of the filter 11 to the air pollutant absorbing part 10 so that the area of contact of the filter 11 with the outside air can be changed.
The measurement characteristics can be adjusted by setting the contact area. At this time, the amount of the absorbing liquid automatically becomes a constant value.

Further, in this case, as shown in FIG. 2, for example, the exclusion body 17 having a predetermined volume is inserted into the space inside the air pollutant absorption section 10 to fill the air pollutant absorption section 10 with the liquid. It is designed to reduce the amount.

Further, in this case, for example, as shown in FIG. 1, the air in the second container 6 is sucked by the air pump 22 as the discharging means to reduce the air pressure in the second container 6, Due to this decrease in air pressure, the liquid in the air pollutant absorption section 10 is sucked up into the second container 6, and after the suction, the liquid in the first container 1 is transferred into the air pollutant absorption section 10 It is designed to be filled in.

Further, in this case, for example, as shown in FIG. 9, a liquid whose optical characteristics change due to absorption of air pollutants is used as a measuring means for detecting the change of the optical characteristics. The light emitted from the light source 32 in the air pollutant absorption unit 10 into the liquid is made incident on the tip of the optical fiber cable 33 inserted in the air pollutant absorption unit 10, and the light receiving means is passed through the optical fiber cable 33. Air pollutant absorber 1
The optical path length from the light source 32 to the tip of the optical fiber cable 33 can be changed within 0, and the measurement characteristics can be adjusted by setting the optical path length.

[0011]

According to the present invention, it is possible to efficiently measure the concentration of pollutants by using a filter that does not allow liquid to permeate but allows outside air to pass. In this case, since the filter is detachable, the filter can be replaced as appropriate, the deterioration of the measurement accuracy due to the deterioration of the filter can be suppressed, and the contact area with the outside air can be adjusted to allow the filter to permeate the outside air. Even if the characteristics are not uniform, the adjustment can be performed so that the uniform characteristics can be measured with high accuracy.

Further, by inserting an excluding body having a predetermined volume into the space inside the air pollutant absorption section to reduce the filling amount of the liquid into the air pollutant absorption section, the liquid (reagent) necessary for the measurement can be stored. It saves the amount and enables continuous measurement for a long time.

Further, since the air pressure in the second container is lowered by suction by the air pump so that the liquid in the air pollutant absorbing portion is sucked up into the second container, a simple air pump is used. With the configuration, the measurement liquid can be easily replaced.

Furthermore, when the optical characteristics of the liquid are detected using an optical fiber cable, the optical path length from the light source to the optical fiber cable can be adjusted, so that the detection sensitivity can be adjusted according to the measured concentration. Easy to do.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the automatic air pollutant measuring device of the present invention will be described below with reference to FIGS.

FIG. 1 is a diagram showing the overall configuration of the measuring instrument of this embodiment. In FIG. 1, reference numeral 1 denotes an absorbent supply container, in which an absorbent required for measurement is stored. Then, the lower end of the supply container 1 is connected to the lower end of the air pollutant absorbing section 10 via the pipe 2, the control valve 3 and the pipe 4. In this case, the control valve 3 acts so as to shut off between the pipe 2 and the pipe 4 when the pressure obtained through the pipe 9 described later becomes less than the pressure of the outside air, and the control valve 3 is obtained through the pipe 9. When the applied pressure returns to normal, it acts to establish conduction between the pipe 2 and the pipe 4. Further, the air pollutant absorption unit 10 is arranged so as to be located below the lower end of the supply container 1.

The air pollutant absorbing portion 10 has a space inside which a liquid can be filled, and a Teflon filter 11 is attached to the upper portion thereof. The Teflon filter 11 is a filter made of a water-repellent porous film formed so that liquid does not permeate and outside air permeates, and as shown in FIG.
It is formed into a cylindrical shape having an opening a, and is inserted into the upper portion of the main body 12 forming the air pollutant absorbing portion 10 with the one end 11a facing downward. Then, the lid 15 is attached between the outer peripheral portion of the inserted filter 11 and the upper end portion 12a of the main body 12, and is assembled as shown in FIG. In this case, an O-ring 16 made of rubber or the like is interposed between the outer peripheral portion of the filter 11 and the lid 15 so that the liquid inside the main body 12 does not leak to the outside.

Since the air pollutant absorbing section 10 is constructed as described above, the filter 11 can be freely replaced by simply removing the lid 15. Moreover, the insertion position of the filter 11 can be freely set. That is, by determining the position of the O-ring 16 on the outer periphery of the filter 11, the protruding length of the filter 11 when the lid 15 is attached is determined, and the adjustment of the position of the O-ring 16 indicates the arrow a in FIG. Thus, the protruding length of the filter 11 (that is, the area where the filter 11 contacts the outside air) can be adjusted.

Then, on the side surface of the main body 12, a light source 13 in which a light emitting element such as a light emitting diode is housed and a light receiving portion 14 in which a light receiving element such as a photodiode is housed are attached so as to face each other. In this case, as shown in the cross-sectional view of FIG.
Mounting location 12b and mounting location 12c of the light receiving section 14
Means to be transparent so that the light is transmitted from the light source 13 to the light receiving portion 14 (the optical path indicated by the arrow in FIG. 4).
The other parts are painted black and light-shielded. As shown in FIG. 1, the light source 13 and the light receiving unit 14 are connected to the measurement control unit 2 via the signal lines 13a and 14a.
Connect to the 0 side.

Further, in this example, the exclusion body 1 shown in FIG.
7 is arranged inside the filter 11 as shown in FIG. The excluding body 17 is composed of an object into which liquid does not penetrate. By disposing the excluding body 17, the volume of the space in which the liquid can be filled inside the air pollutant absorbing section 10 is reduced by the volume of the excluding body 17. A plurality of legs 17a are attached to the lower end of the excluding body 17 so that the excluding body 17 does not interfere with the optical path from the light source 13 to the light receiving section 14 (see FIG. 4).

Returning to the explanation of FIG. 1 again, one end of the pipe 5 is attached to the lower end of the air pollutant absorbing portion 10, and the other end of the pipe 5 is connected to the upper end of the absorbent collecting container 6. . Further, the upper end of the absorbent recovery container 6 is connected to the control valve 3 side via the pipe 7, the differential pressure partition wall 8 and the pipe 9, and the control valve 3 is controlled by the pressure inside the absorbent recovery container 6. In this case, the pipe 5 is arranged such that the intermediate portion is routed to a position higher than the upper end of the supply container 1.

An air pump 22 is attached to the upper end of the absorbent recovery container 6 via a pipe 21. The air pump 22 sucks out the air in the absorbent recovery container 6 to increase the air pressure in the container 6. It can be lowered. This air pump 22 has a signal line 22a.
The air pump 22 is connected to the measurement control unit 20 via the, and the timer provided in the measurement control unit 20 operates the air pump 22 at predetermined time intervals (for example, every one hour).

Further, the pressure gauge 2 is provided in the absorption liquid recovery container 6.
3 is attached, and the pressure value detected by the pressure gauge 23 is supplied to the measurement control unit 20 via the signal line 23a.

On the measurement control unit 20 side, after the air pump 22 is operated at a predetermined time by a timer, the pressure value detected by the pressure gauge 23 once decreases and then returns to the original value. The operation of 22 is stopped.

Further, the measurement control unit 20 includes a signal line 24
The light source 24 and the light receiving unit 25 are connected via a and 25a. As the light source 24 and the light receiving section 25, a light emitting element and a light receiving element having the same characteristics as the light source 13 and the light receiving section 14 attached to the air pollutant absorbing section 10 are used, and the light source 24 and the light receiving section 25 are brought into close contact with each other. Then, the light from the light source 24 is directly incident on the light receiving unit 25. Then, the received light amount data is supplied to the measurement control unit 20. Further, if necessary, the absorbing liquid may be allowed to enter between the light source 24 and the light receiving unit 25 so as to cancel the change in the absorbing liquid.

Next, the operation of the measuring machine configured as described above will be described. First of all, when measuring with this measuring machine,
The absorbing liquid supply container 1 is filled with a sufficient amount of liquid that absorbs contaminants. Note that, here, it is assumed that the liquid absorbs a contaminant to change the color and the light transmittance changes according to the absorption amount. As such an absorbing liquid, for example, when measuring nitrogen dioxide, a so-called Salzman reagent is used.

By injecting the absorption liquid into the supply container 1, as shown in FIG.
As indicated by hatching, the absorbing liquid is also filled in the air pollutant absorbing portion 10 located below the supply container 1.
Since the filter 11 that allows air to permeate is attached to the upper portion of the air pollutant absorption unit 10, the air in the filter 11 is completely removed, and the air pollutant absorption unit 10 is removed.
The entire inner space is filled with the absorbing liquid.

By filling the air pollutant absorbing portion 10 with the absorbing liquid in this way, the absorbing substance absorbs the pollutant that has permeated from the outside to the inside through the filter 11. At this time, the amount of absorption is determined by the area where the filter 11 contacts the outside air (that is, the amount of the filter 11 exposed to the outside).
In this state, the measurement control unit 20 side monitors the amount of light received by the light receiving unit 14 of the light emitted from the light source 13. Then, the absorption amount of the pollutant is detected from the change state of the received light amount, and the concentration of the pollutant in the air is calculated from the detected data. In this case, the data of the amount of light received by the light receiving unit 25 of the light from the light source 24 directly connected is compared with the data of the amount of light received by the light receiving unit 14, and the data of the difference is used to determine the absorption amount. To detect. As described above, by using the output of the light receiving unit 25 as a reference, the measured value is not affected by the fluctuation of the power supply voltage or the change of the absorbing liquid.

Then, when a certain time (here, one hour) elapses after the air pollutant absorption unit 10 is first filled with the absorbing liquid, the timer in the measurement control unit 20 activates the air pump 22. The air in the absorbent collection container 6 is sucked out, and the air pressure in the container 6 decreases. This decrease in air pressure is detected by the pressure gauge 23, and as shown in FIG.
It is detected that the atmospheric pressure P ₁ has decreased by a predetermined amount to the atmospheric pressure P ₂ .

When the air pressure in the container 6 is lowered in this way, as shown in FIG.
The absorbing liquid used for the time measurement is sucked out to the collection container 6 side. At the same time, the decrease in the air pressure is also transmitted to the control valve 3 side via the pipes 7 and 9 to act to close the control valve 3. Therefore, in this state, the flow of the absorbing liquid from the supply container 1 to the air pollutant absorbing portion 10 side is blocked,
Only the absorbing liquid in the air pollutant absorbing section 10 is sucked into the collecting container 6. At this time, since air permeates from the outside of the filter 11 as indicated by a dashed arrow in FIG. 6, the absorbing liquid in the air pollutant absorbing portion 10 can be sucked out.

When all the absorbing liquid in the air pollutant absorbing section 10 is sucked into the collecting container 6, the control valve 3 operates by the action of the differential pressure dividing wall 8 between the pipe 7 and the pipe 9. It becomes impossible to shut off the control valve 3 as shown in FIG.
Is opened, the absorption liquid flows from the supply container 1 to the air pollutant absorption unit 10 side, and the air absorption unit 10 is filled with a new absorption liquid, returning to the state shown in FIG. Waste liquid accumulates on the side).

At the same time that all the absorbing liquid in the air pollutant absorbing section 10 is sucked into the recovery container 6, the atmospheric pressure in the recovery container 6 returns to the original pressure P ₁ (see FIG. 8). When this is detected by the measurement control unit 20 from the detection data of the pressure gauge 23, the air pump 22 is stopped. The above operation is repeated every hour, and the measurement is continuously performed until the absorption liquid in the supply container 1 is exhausted.

By performing the measurement in this way, the contamination concentration can be measured well. That is, in the case of this example, since the filter 11 is removable, the filter 11 can be replaced as appropriate, and the deterioration of the measurement accuracy due to the deterioration of the filter 11 can be suppressed. Further, although the normal Teflon filter 11 has some variation in the characteristics of allowing air to pass through, by adjusting the protruding length of the filter 11, that is, the contact area with the outside air, the reference data becomes a constant value in advance. By adjusting the protrusion length to a reference state that can be detected, it is possible to set such that any filter 11 can be used for accurate measurement.

Further, in the present embodiment, the exclusion body 17 having a predetermined volume is inserted into the space inside the air pollutant absorption section 10 to reduce the filling amount of the liquid into the air pollutant absorption section. The amount of the absorption liquid required for the measurement of 1 is reduced by that much, and the time for continuous measurement can be lengthened by replenishing the supply container 1 with the liquid once. If the size of the filter 11 can be freely set, it is not necessary to use such an excluding body 17, but in reality, a Teflon filter that is currently on the market can be used only if the size is limited. Therefore, by arranging the exclusion body 17, it has become possible to reduce the amount of absorption liquid required for one measurement for the first time.

Further, since the air pressure in the recovery container 6 is lowered by suction by the air pump 22 so that the liquid in the air pollutant absorbing portion 10 is sucked up into the recovery container 6, the absorption liquid can be easily absorbed. Can be exchanged. In this case, since it is sufficient to suck up all the liquid filled in the air pollutant absorption unit 10, fine control of the suction amount is not required, and it is realized by simple control. In addition, in the case of this example, since the air pollutant absorbing section 10 is connected to the supply container 1, the evaporated portion of the absorbing liquid is automatically replenished from the supply container 1 and the liquid amount is always kept constant. Be done. In addition, in order to save the absorption liquid, it is also possible to supplement the evaporation with distilled water.

Thus, the measurement of the contamination concentration with high accuracy is
Since it can be realized with a simple configuration, it can be configured as a small and inexpensive automatic measuring machine, and it becomes possible to measure air pollution without bothering and cost. Therefore, for example, it becomes easier to increase the number of measurement points than in the conventional case, and it becomes possible to accurately measure the pollution concentration over a wide area.

In the above embodiment, pressures P ₂ to P ₁
The air pump 22 is stopped by detecting the change to the above condition, but at time t ₁ when this pressure is P ₂ , that is, all the absorbing liquid in the air pollutant absorbing portion 10 is sucked out by the air pump 22. It is also possible to measure the time required for the operation in advance and operate the pump 22 only for this time. By doing so, the pressure gauge 23 can be omitted. Further, although the control valve 3 is used to control the flow of the absorbing liquid, the supply container 1 to the air pollutant absorbing portion 10 is controlled.
By omitting the control valve 3, the flow rate of the absorbing liquid per unit time is set to be sufficiently smaller than the flow rate per unit time sucked from the air pollutant absorbing section 10 to the collection container 6 side. You can The setting of this flow rate is performed by the thickness of the pipe, the capacity of the pump, and the like.

Further, in the above-mentioned embodiment, the light source 13 and the light receiving portion 14 are directly attached to the main body 12 of the air pollutant absorbing portion 10.
However, as shown in FIG. 9, the light from the separately provided light source 31 is connected to the optical fiber cable 32.
It is guided to the inside of the main body 12 via. Then, the light emitted from the tip of the optical fiber cable 32 is made incident on the optical fiber cable 33 arranged at the opposite position, and is received by the light receiving section 34 provided outside through the optical fiber cable 33. Is also good. In this case, the optical fiber cables 32 and 33 are inserted into the main body 12 through the through holes 12d and 12e of the main body 12, and the distance between the ends of the cables 32 and 33 (that is, the optical path length through which the absorbing liquid passes) L By making it possible to freely adjust, it becomes possible to perform appropriate adjustment according to the measured contamination concentration. That is, when the measurement is performed in a place where the concentration of contamination is high, the optical path length L is set to be short so that the measurement can be performed well even in a high concentration state. On the contrary, in a place where the pollution concentration is relatively low,
Good measurement can be performed by setting the optical path length L to be long.

Although the optical fiber cables are attached to both the light source and the light receiving portion in the example of FIG.
For example, even if the light source is directly attached to the main body 12 as in the example of FIG. 1 so that only the light receiving portion side receives light through the optical fiber cable, the optical path length L can be similarly adjusted.

In the above embodiment, the filter 11 is filled with the absorbing liquid.
May be installed in the opposite direction so that the outside air is introduced into the inside of the filter. That is, for example, as shown in FIG. 10, by attaching the Teflon filter 11 ′ with the opening 11 a facing upward and inserting the curved tip 11 b into the main body 12, the tip 11 b The insertion area becomes the contact area with the outside air, the contaminants are absorbed by the absorbing liquid in the main body 12, and the same concentration measurement as in the above-described embodiment is performed. However, in this case, it is necessary to provide the fan device 41 and the duct 42 connected to the fan device 41 to forcibly introduce the outside air into the filter 11 '.
In this case, since it is not necessary to control the amount of outside air introduced, the cost is low.

Further, in the above-mentioned embodiment, the concentration of the absorbing liquid in the air pollutant absorbing portion 10 is kept uniform by being cooled by evaporation from the filter surface and causing convection.
If necessary, a minute heating element or a buzzer vibrator may be used to forcibly cause convection to make the temperature uniform.

Further, in the above-mentioned embodiment, the concentration of the absorbed pollutant is optically detected, but it can be applied to the case where the concentration of the pollutant is detected from other characteristics such as conductivity. In this case, the measuring means (the light source and the light receiving section in the above-described embodiment) attached to the air pollutant absorbing section 10 may be replaced with corresponding ones.

[0043]

According to the present invention, it is possible to efficiently measure the concentration of pollutants by using a filter that does not allow liquid to permeate but allows outside air to pass. In this case, since the filter is detachable, the filter can be replaced as appropriate, the deterioration of the measurement accuracy due to the deterioration of the filter can be suppressed, and the contact area with the outside air can be adjusted to allow the filter to permeate the outside air. Even if the characteristics are not uniform, it can be easily adjusted so that accurate measurements can be made with uniform characteristics, and it is also possible to perform accurate measurements while maintaining a constant liquid volume.

Further, by inserting an excluding body of a predetermined volume into the space inside the air pollutant absorption section to reduce the filling amount of the liquid into the air pollutant absorption section, the amount of liquid (reagent) required for measurement can be reduced. It reduces the amount and enables continuous measurement for a long time.

Further, the air pressure in the container to be collected by suction with the air pump is lowered so that the liquid in the air pollutant absorption section is sucked up into this container, so that the air pump has a simple structure. The measurement liquid can be easily replaced.

Furthermore, when the optical characteristics of the liquid are detected using an optical fiber cable, the optical path length from the light source to the optical fiber cable can be adjusted, so that the detection sensitivity can be adjusted according to the measured concentration. Easy to do.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an overall configuration of a measuring machine according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an air pollutant absorbing portion of one embodiment.

FIG. 3 is a perspective view showing a state in which an air pollutant absorbing portion of one embodiment is assembled.

FIG. 4 is a cross-sectional view showing an air pollutant absorbing portion of an embodiment.

FIG. 5 is an explanatory diagram showing a liquid exchange process according to an embodiment.

FIG. 6 is an explanatory diagram showing a liquid exchange process of one embodiment.

FIG. 7 is an explanatory diagram showing a liquid exchange process according to an embodiment.

FIG. 8 is a characteristic diagram showing a pressure change of an example.

FIG. 9 is a cross-sectional view showing an air pollutant absorbing portion according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view showing an air pollutant absorbing portion according to still another embodiment of the present invention.

[Explanation of symbols]

 1 Absorbing liquid supply container 2, 4, 5, 7, 9, 21 Pipe 3 Control valve 6 Absorbing liquid collecting container 8 Differential pressure partition 10 Air pollutant absorbing part 11, 11 'Teflon filter 12 Main body 13, 24, 31 Light source 14 , 25, 34 Light receiving part 17 Exclusion body 20 Measurement control part 22 Air pump 32, 33 Optical fiber cable

Claims (4)

[Claims] 1. A first container for containing a liquid whose state is changed by absorption of air pollutants, and a water-repellent filter for allowing the liquid to permeate the outside air without being permeated, and the first container is detachably mounted. An air pollutant absorption part which can be filled with the liquid supplied from the inside, a measuring means for measuring the state of the liquid in the air pollutant absorption part, and the liquid filled in the air pollutant absorption part And a discharge means for discharging to a container of No. 2, and by adjusting the mounting position of the filter to the air pollutant absorption part, the area of contact of the filter with the outside air can be changed. An air pollutant automatic measuring device characterized in that the measurement characteristics can be adjusted. 2. An exclusion body having a predetermined volume is inserted into the space inside the air pollutant absorption section to reduce the filling amount of the liquid into the air pollutant absorption section. Item 1. An air pollutant automatic measuring instrument according to item 1. 3. As the discharging means, the air in the second container is sucked by an air pump to reduce the air pressure in the second container, and the decrease in the air pressure causes the air pollutant absorbing section to absorb air. The liquid is sucked into the second container, and after the sucking, the liquid in the first container is filled in the air pollutant absorbing section. 1. An air pollutant automatic measuring instrument according to 1. 4. As the liquid, a liquid whose optical characteristics change due to absorption of air pollutants is used, and as the measuring means for detecting this change in optical characteristics, light emission in the air pollutant absorbing section is used. The light emitted from the part into the liquid is made incident on the tip of the optical fiber cable inserted into the air pollutant absorption part, and is guided to the light receiving means through the optical fiber cable. 2. The air pollutant automatic system according to claim 1, wherein the optical path length from the light emitting section to the tip of the optical fiber cable is made variable, and the measurement characteristics can be adjusted by setting the optical path length. Measuring machine.