JP2004163371A - Gas detection material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas detection material for measuring a tested gas of a wide concentration range with high accuracy while keeping constant the concentration of a reaction reagent. <P>SOLUTION: This detection material is equipped with color reaction base material 4 in which the reaction reagent color-reacting with the tested gas is carried on a carrier and a film 3 having permeability with respect to the tested gas, and is structured so that the film 3 is layered at least on the inflow surface side of the base material 4. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a gas detection material that carries a coloring agent and detects the concentration of a gas from the optical density of a reaction trace caused by a reaction with a detection gas.
[0002]
[Prior art]
Certain gases, such as hydrogen sulfide, require the detection of very high concentrations from crude oil in hold from very low concentrations of environmental standards.
In order to detect such a wide range of gas concentrations using a gas detection material that detects the optical density change due to a chemical reaction, for example, a gas detection tape disclosed in Patent Document 1, the concentration range to be detected must be within the range of each detection target. It is also conceivable to adjust the concentration of the reaction reagent correspondingly.
[Patent Document 1]
JP 06-18509A
[0003]
[Problems to be solved by the invention]
However, in addition to the problem that it takes time and effort to manufacture a wide variety of products, if the concentration of the reaction reagent is reduced to cope with high-concentration gas, it is more susceptible to the volatilization of the reaction reagent, and the measurement accuracy is reduced. There is a problem of lowering.
The present invention has been made in view of such a problem, and an object of the present invention is to provide a gas detection capable of measuring a test gas in a wide concentration range with high accuracy while keeping the concentration of a reaction reagent constant. To provide materials.
[0004]
[Means for Solving the Problems]
In order to achieve such a problem, in the present invention, a color reaction substrate having a reaction reagent that performs a color reaction with a test gas supported on a carrier, and a membrane having permeability to the test gas. And the film is laminated on at least the inflow surface side of the test gas of the color reaction substrate.
According to this, the amount of the test gas permeated by the membrane is limited, and even if the test gas has a high concentration, the reaction amount of the reaction reagent can be suppressed and the measurement can be reliably performed.
[0005]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Therefore, the details of the present invention will be described below based on the illustrated embodiment.
FIG. 1 shows an embodiment of the present invention, in which a tab is configured so as to be easily mounted on a detector.
The frame 2 constituting the tab 1 is configured to be engageable with an upper frame 21 having a through hole 21a, a lower frame 22 having a through hole 22b, a claw 21b, and a window 22b. A membrane 3 through which a test gas can pass is disposed at least on the gas inflow side so as to close it, and a color reaction substrate 4 that produces a reaction mark by a color reaction in a state of being preferably adhered to the lower surface thereof is laminated. ing. As such a film 3, a silicon rubber film, a polyethylene film, or the like is suitable.
[0006]
In addition, if the tongue piece 3a is formed at the end of the film 3 as shown in FIG. 2, the film 3 can be easily removed from the color reaction substrate 4 at the time of measuring the optical density, and reliable measurement can be performed. It becomes.
[0007]
When the tab 1 configured as described above is set between the sampling head 11 and the measurement head 12 of the measurement device 10 as shown in FIG. The test gas passes through the color reaction substrate 4 while receiving the ventilation resistance of the membrane 3. Accordingly, even when the concentration of the test gas is extremely high, sampling can be performed for a specified time set in the measurement device 10, and the gas can be detected with high accuracy.
[0008]
By the way, the color reaction base material is, for example, as shown in Patent Document 1, in order to reliably perform the reaction between the test gas and the reaction reagent, a carrier such as cellulose impregnated with fine particles of silica gel, For example, a reagent capable of performing a color reaction with the test gas, for example, hydrogen sulfide, is impregnated with a mixture of silver perchlorate, paratoluenesulfonic acid, and a humectant.
[0009]
When measuring a gas having a concentration approximately equal to the environmental standard, a reaction trace having an optical density corresponding to the concentration of the gas can be generated by using the above-described color reaction substrate 4 as it is. The reaction marks can be easily measured by an optical method, that is, a method of irradiating the reaction marks with a fixed amount of light from the light emitting means 15 of the measuring head 12 and detecting the reflected light by the light receiving means 16.
[0010]
On the other hand, when the concentration of a test gas having an extremely high concentration, for example, the concentration of hydrogen sulfide in a hold containing crude oil is to be measured, the above-described tab is set in the sampling device. Since the amount of the sampled test gas reaching the color reaction substrate is limited to a specified value, for example, 10 −5, due to the gas flow resistance of the membrane, the reaction amount of the reaction reagent is suppressed. The measurement can be performed at the sampling time specified in the above.
[0011]
At the end of the measurement, the film is removed, the optical density of the reaction trace is measured by the above-mentioned optical method, and the gas concentration can be known by multiplying by the reduction rate of the gas flow rate by the film.
[0012]
Since silicon rubber and polyethylene have low light reflectance, even if the optical density is measured without removing the film from the tab, the error is at most about 5%, and the reduction rate of the light amount is known. Therefore, the correction can be easily made by multiplying the coefficient.
[0013]
In addition, when measuring hydrogen sulfide at a medium concentration using the same color reaction substrate, the membrane is subjected to a porous treatment to reduce the airflow resistance, so that the same sampling time as described above can be obtained. Can be measured.
[0014]
As described above, at least the surface of the color reaction substrate has a film having airflow resistance, so that not only a high-concentration test gas can be detected by the color reaction substrate of the same specification but also during storage. In that case, a function of preventing the volatilization of the coloring reagent is exhibited, so that long-term storage becomes possible.
[0015]
In the above-described embodiment, the detection material is configured as a tab. However, as shown in FIG. 4, the film 3 is laminated on at least the side of the color reaction substrate 4 that is exposed to the test gas. The same effect can be obtained even if the bag is formed and stored in a bag shape.
[0016]
Further, in the above-described embodiment, hydrogen sulfide is detected, but a similar effect can be obtained when the present invention is applied to a test gas having a significantly different concentration in a measurement range such as formaldehyde.
[Brief description of the drawings]
FIGS. 1 (a) and 1 (b) are an assembly perspective view and a sectional view, respectively, showing an embodiment of a gas detection material of the present invention.
FIG. 2 is a sectional view showing another embodiment of the detection material of the present invention.
FIG. 3 is a sectional view showing an embodiment of a measuring means suitable for the above-mentioned detecting material.
FIGS. 4A and 4B are a top view and a sectional view, respectively, showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tab 2 Frame 3 Membrane 4 Color reaction substrate

Claims (6)

A color reaction base material in which a reaction reagent that undergoes a color reaction with the test gas is supported on a carrier, and a membrane having a permeability to the test gas, wherein at least the test A gas detection material formed by laminating the film on the gas inflow surface side. The gas detecting material according to claim 1, wherein the film is formed of a polymer film. 3. The gas detection material according to claim 1, wherein the film is made of silicon rubber or polyethylene. The gas detection material according to claim 1, wherein the film is subjected to a porous treatment. The gas detection material according to claim 1, wherein the carrier is formed of a sheet having gas permeability and containing silica gel on at least a reaction surface, and the reaction reagent is silver perchlorate and paratoluenesulfonic acid. The gas detection material according to claim 1, wherein the film is formed in a bag shape so as to accommodate the color reaction substrate.

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