JP2005062026A - Method, apparatus, and detection tube for measuring gas concentration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform measurement of the concentration of a gas component at low cost, in real time, with high precision, and using unattended measurement and remote operations. <P>SOLUTION: A transparent container 11 is filled with a granulated detection agent 12 which changes color by reaction with a predetermined gas component. The gas component is introduced from one end 11A of the transparent container 11 and reacts with the detection agent 12 to form a discolored layer X. The concentration of the gas component is measured by deriving the length of the discolored layer X. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gas concentration measuring method and a gas concentration measuring apparatus that can be used in fields such as information engineering, electronic engineering, and environmental engineering.

  Conventionally, a detector tube has been used to measure the gas concentration. The detection tube is easy to handle and can detect the concentration of the target gas component simply and in a short time regardless of the level of skill of the operator.

  However, the conventional detector tube is a disposable type, which is discarded after the measurement of the gas component, and a new detector tube needs to be prepared for each gas component measurement, which causes high costs. Further, in the gas component concentration measurement using the detection tube described above, the concentration of the gas component at a specific time can only be measured, and real-time measurement cannot be performed.

  Furthermore, since the operator visually reads the color change scale of the detection tube, there is a problem that the measurement error of the gas component concentration increases. Moreover, since it was necessary for the operator to read the scale of the detection tube one by one, it was not possible to measure the gas component concentration by unattended measurement or remote operation.

  It is an object of the present invention to perform gas component concentration measurement with high accuracy in real time at a low cost, and to perform gas component concentration measurement using unattended measurement or remote control.

In order to achieve the above object, the present invention provides:
Filling a transparent container with a granular detection agent that reacts with a predetermined gas component and changes color; and
Introducing the gas component from one end of the transparent container and reacting with the detection agent to form a discoloration layer;
Measuring the concentration of the gas component from the length of the color changing layer in the transparent container;
It is related with the gas concentration measuring method characterized by comprising.

The present invention also provides:
The present invention relates to a gas concentration measuring apparatus comprising a transparent container filled with a granular detection agent that changes color by reacting with a predetermined gas component.

Furthermore, the present invention provides
The present invention relates to a gas concentration measurement detector tube comprising a transparent container filled with a granular detector that changes color by reacting with a predetermined gas component.

  In the present invention, a transparent container filled with a granular detection agent that reacts with a predetermined gas component and changes color, and when the gas component is introduced into the transparent container, the gas component and the detection agent A discolored layer generated through the reaction is obtained. The length of the color changing layer is proportional to the concentration of the gas component, and the length of the color changing layer increases as the concentration of the gas component increases. Therefore, the concentration of the gas component can be indirectly measured by deriving the length of the color changing layer.

  If a graph showing the correlation between the length of the color changing layer and the gas component concentration is prepared in advance, the gas component concentration can be determined only by deriving the length of the color changing layer.

  In the present invention, the transparent container filled with the detection agent has the same function as a conventional detection tube. However, in the present invention, if the detection agent in the transparent container is replaced, the transparent container The container itself can be used repeatedly for gas concentration measurements. Therefore, the cost for the gas concentration measurement can be reduced. Furthermore, if the detection agent is composed of a reversible reactive substance, the transparent container filled with the detection agent can be used repeatedly for gas concentration measurement without replacing the detection agent. .

  Further, since the length of the color changing layer described above changes according to the change in the concentration of the gas component to be measured, the concentration of the gas component can be measured in real time.

  Further, although the length of the color changing layer can be visually measured, the image is picked up using a predetermined imaging device, the color changing layer is obtained as an image, and the image is analyzed using image processing means such as a computer. If the length of the discoloration layer is automatically measured, the gas concentration can be measured remotely or unattended.

  When the length of the color changing layer is derived from image analysis, a piecewise quadrature method or the like can be used. In the original image, since the detection tube is filled with the detection agent, noise caused by the detection agent or the like is mixed, and it is difficult to determine the boundary of the color change layer and further the length of the color change layer. There is a case.

  Further, in order to remove noise in the image (image signal), filtering can be performed, and further, an original image of the transparent container filled with the detection agent is obtained, and the original image and the image By taking the difference, noise in the image (image signal) caused by the detection agent or the transparent container can be removed.

  As described above, according to the present invention, the gas component concentration can be measured with high accuracy in real time at low cost, and the concentration measurement of the gas component can be performed using unattended measurement or remote control. Can do.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram showing a part of a gas concentration measuring apparatus according to the present invention. The gas concentration measuring apparatus shown in FIG. 1 includes a transparent container 11 made of, for example, glass and filled with a detection agent 12, and a scanner 13 as an imaging device arranged so as to be adjacent to the transparent container 11. Yes. However, the scanner 13 can be replaced with a digital camera.

  The detection agent 12 is made of a substance that reacts with a predetermined gas component to be measured and changes its color. For example, a granular material such as silica gel or alumina coated with a predetermined reagent can be used. In this case, the reagent reacts with the gas component and changes its color. The type of the reagent is determined by appropriately selecting from the commercially available reagents according to the type of gas component to be measured.

  When a gas containing a gas component to be measured is introduced from the inlet 11A of the transparent container 11, the gas component reacts with the detection agent 12 to change its color, thereby forming a discoloration layer X on the inlet 11A side. . The remaining components that do not react with the detection agent are released from the outlet 11B of the transparent container 11.

  Thereafter, the entire transparent container 11 including the discoloration layer X is photographed by the scanner 13, and the image is taken into a computer as image processing means (not shown). In the computer, the boundary between the color changing layer X in the detection agent 12 and the non-color changing layer Y located on the outlet 11B side is determined, and the length of the color changing layer X is determined based on the boundary. Since the length of the color changing layer X is proportional to the concentration of the gas component to be measured, by identifying the length of the color changing layer X, the concentration of the gas component can be measured.

  At this time, if a graph showing the correlation between the length of the color changing layer X and the gas component concentration is prepared, the concentration of the gas component can be quantified by identifying the length of the color changing layer X. In addition, since the length of the color changing layer X changes according to the gas component concentration, the gas component concentration can be measured in real time by identifying the length of the color changing layer X.

  FIG. 2 is a diagram for explaining a method for deriving the length of the color-changing layer X by using the piecewise quadrature method. In this example, it is assumed that the color-changing layer X exhibits yellow and the non-color-changing layer Y exhibits white. ΔX is the sampling interval, n is the number of data, yellow ave is the average value of yellow of the color-changing layer X, white ave is the average value of white of the non-color-changing layer Y, and L is the length of the color-changing layer X. The length L can be expressed by the following formula.

  The above equation determines an average boundary by taking an average value over the entire length direction of the color changing layer X and determining a contribution ratio of yellow ave and white ave to the average value.

  When the length of the color changing layer X is derived by the image processing as described above, it is preferable to perform filtering on the image signal including the color changing layer X to remove noise included in the image signal. The filtering can be performed using a spatial filter or the like. However, the filtering can be performed independently without performing the image processing described above.

  When the length of the color changing layer 13 is derived by the above-described image processing, the obtained image (image signal) includes a large number of noise signals due to reflection of the detection agent 12 and the transparent container 11. In some cases, the length of the discoloration layer X cannot be accurately identified. In such a case, before measuring the gas concentration, the entire transparent container 11 including the detection agent 12 is photographed by the scanner 13 to obtain an original image, and this original image (original image signal) and the image (image signal) are obtained. It is preferable to take the difference between and.

  Since the original image (original image signal) includes a large number of noise signals caused by reflection of the detection agent 12 and the transparent container 11, the original image (original image signal) and the image (image signal) are included. ), It is possible to effectively remove only the noise signal from the image (image signal). As a result, it becomes possible to accurately identify the length of the color changing layer X by the above-described image processing.

  According to the image processing as described above, since the length of the discoloration layer X can be identified without involving an operator, the gas concentration measurement can be performed unattended, and the gas concentration measurement can be performed by remote control. Will be able to. In addition, it is possible to reduce the reading error of the length of the color changing layer X between workers, and to perform the gas concentration measurement with higher accuracy.

  However, even if the length of the discoloration layer X is read artificially, the accuracy of the gas concentration measurement due to a reading error or the like is reduced, but the transparent container 11 containing the detection agent 12 for the gas concentration measurement. The frequency of use of the gas increases, and the cost reduction of the gas concentration measurement can be achieved.

  FIG. 3 is a modification of the gas concentration measuring apparatus shown in FIG. In the gas concentration measuring apparatus shown in FIG. 3, a plurality of transparent containers 11 are arranged, and a scanner 13 is disposed adjacent to the transparent containers 11. The plurality of transparent containers 11 are filled with different types of granular detection agents. Accordingly, each transparent container 11 functions as a detection tube only for specific gas components different from each other, and only the specific gas component reacts with the detection agent filled in each transparent container 11 to form a discoloration layer. Will come to do.

  Therefore, if a gas containing a plurality of gas components is introduced into the apparatus shown in FIG. 3, the concentrations of the plurality of gas components can be measured simultaneously.

  The length of the color changing layer in each transparent container 11 can be derived in the same manner as in the case of using the apparatus shown in FIG.

  As described above, the present invention has been described in detail based on the embodiments of the present invention with specific examples. However, the present invention is not limited to the above contents, and all modifications and changes are made without departing from the scope of the present invention. It can be changed.

It is a block diagram which shows a part of gas concentration measuring apparatus of this invention of this invention. It is a figure for demonstrating the method of deriving the length of a discoloration layer using a division | segmentation quadrature method. It is a modification of the gas concentration measuring apparatus shown in FIG.

Explanation of symbols

11 Transparent container 12 Detection agent 13 Scanner

Claims (18)

Filling a transparent container with a granular detection agent that reacts with a predetermined gas component and changes color; and
Introducing the gas component from one end of the transparent container and reacting with the detection agent to form a discoloration layer;
Measuring the concentration of the gas component from the length of the color changing layer in the transparent container;
A gas concentration measurement method characterized by comprising:   Prepare a plurality of transparent containers filled with granular detectors that react with different gas components and change color, introduce a plurality of gas components from one end of the plurality of transparent containers, and simultaneously adjust the concentrations of the plurality of gas components. The gas concentration measurement method according to claim 1, wherein measurement is performed.   The gas concentration measurement method according to claim 1, wherein the length of the discoloration layer is visually observed.   The gas concentration measurement method according to claim 1, wherein an image is obtained by imaging the discoloration layer, and the length of the discoloration layer is measured by analyzing the image.   The gas concentration measurement method according to claim 4, wherein the image is captured using a scanner or a digital camera.   6. The gas concentration measuring method according to claim 4, wherein the image is subjected to a sectional quadrature method to identify the length of the discoloration layer.   The gas concentration measurement method according to claim 4, wherein filtering is performed on the image to remove noise in the image.   The gas concentration measurement method according to claim 7, wherein the filtering is performed using a spatial filter.   The noise in the image is removed by obtaining an original image of the transparent container filled with the detection agent and taking a difference between the image and the original image. The gas concentration measurement method according to any one of the above.   The gas concentration measurement method according to claim 1, wherein the concentration change of the gas component is measured in real time.   A gas concentration measuring apparatus comprising a transparent container filled with a granular detection agent that changes color by reacting with a predetermined gas component.   A gas concentration measuring device comprising a plurality of transparent containers filled with granular detection agents that react with different gas components and change color.   The gas according to claim 11 or 12, further comprising an imaging device for imaging a discoloration layer generated by reacting with the gas component of the detection agent filled in the transparent container. Concentration measuring device.   The gas concentration measuring device according to claim 13, wherein the imaging device is a scanner or a digital camera.   The gas concentration measuring device according to any one of claims 11 to 14, further comprising image processing means for processing an image obtained by imaging the discoloration layer.   The gas concentration measuring device according to any one of claims 11 to 15, further comprising filtering means for removing noise from an image obtained by imaging the discoloration layer.   The gas concentration measuring apparatus according to claim 16, wherein the filtering means is a spatial filter.   A detector tube for measuring gas concentration, comprising a transparent container filled with a granular detector that reacts with a predetermined gas component and changes color.

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