JP4093558B2 - Gas detection material - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a gas detection material that carries a colorant and detects the concentration of a gas from the optical density of a reaction mark caused by reaction with a detection gas.
[0002]
[Prior art]
Certain gases, such as hydrogen sulfide, need to be detected from very low concentrations of environmental standards, and very high concentrations generated from crude oil in the hold.
In order to detect such a wide range of gas concentrations as a change in optical density due to a chemical reaction, for example, a gas detection tape found in Patent Document 1, each detection target has a concentration range. It is also conceivable to adjust the concentration of the reaction reagent so as to correspond.
[Patent Document 1]
JP 06-18509
[0003]
[Problems to be solved by the invention]
However, in addition to the problem that it takes time to manufacture a wide variety of products, if the concentration of the reaction reagent is lowered to cope with a high concentration of gas, it is easily affected by 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 problems, and the object of the present invention is to provide a gas detector capable of measuring a gas having a wide concentration range with high accuracy while keeping the concentration of a reaction reagent constant. Is to provide materials.
[0004]
[Means for Solving the Problems]
In order to achieve such a problem, the present invention has a color reaction base material in which a reaction reagent color-reacting with a test gas is supported on a carrier, and has a specified ventilation resistance with respect to the test gas. And a layer that is peelable and laminated on at least the inflow surface side of the test gas of the color reaction base material.
According to this, the permeation amount of the test gas is limited by the membrane, and even when the test gas has a high concentration, the reaction amount of the reaction reagent can be suppressed and reliably measured.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Therefore, details of the present invention will be described below based on the illustrated embodiment.
FIG. 1 shows an embodiment of the present invention, which is configured as a tab for easy loading in a detector.
The frame 2 constituting the tab 1 is configured to be engageable by 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 film 3 capable of transmitting a test gas is disposed at least on the gas inflow side so as to close, and a color reaction base material 4 that generates a reaction mark by a color reaction in a state where it is preferably in close contact with 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 detached from the color reaction base material 4 at the time of optical density measurement, and reliable measurement is possible. It becomes.
[0007]
When the tab 1 having such a configuration is set between the sampling head 11 and the measurement head 12 of the measuring apparatus 10 as shown in FIG. The test gas passes through the color reaction substrate 4 while receiving the ventilation resistance of the membrane 3. Thereby, even when the concentration of the test gas is extremely high, sampling can be performed for a specified time set in the measuring apparatus 10, and the gas can be detected with high accuracy.
[0008]
By the way, the color reaction base material, for example, as seen in Patent Document 1, in order to surely carry out the reaction between the test gas and the reaction reagent, on a carrier such as cellulose constituted by impregnating fine particles of silica gel, For example, a reagent capable of color reaction with the test gas, for example, hydrogen sulfide, is configured to impregnate a mixture of silver perchlorate, paratoluenesulfonic acid, and a humectant.
[0009]
When measuring a gas having a concentration of the environmental standard, the reaction reaction having an optical density corresponding to the gas concentration can be generated by using the color reaction base material 4 as it is. This reaction mark can be easily measured by an optical method, that is, a method of irradiating the reaction mark with a certain 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, extremely high-density gas to be detected, for example when the concentration of hydrogen sulfide hold accommodating a crude oil and the measurement object, sets the tab above the sampling device. Since the sample gas to be sampled is limited in the amount reaching the color reaction base material due to the ventilation resistance of the membrane, the reaction amount of the reaction reagent is suppressed. Measurement at a sampling time determined in (1) is possible.
[0011]
When the measurement is completed, the film is removed and the optical concentration of the reaction trace is measured by the above-described optical method, and the gas concentration can be obtained by multiplying by the rate of decrease in the air flow rate through the film.
[0012]
Silicon rubber and polyethylene have low light reflectivity, so even if the optical density is measured without removing the film from the tab, there is an error of only about 5%, and the reduction rate of the light quantity is known. Therefore, it can be easily corrected by multiplying by a coefficient.
[0013]
In addition, when measuring the medium concentration of hydrogen sulfide using the same colored reaction base material, the membrane is treated with a porous material to reduce the air flow resistance, thereby reducing the ventilation resistance in the same manner as described above. Can be measured.
[0014]
As described above, since a film having a ventilation resistance exists on at least the surface of the color reaction base material, not only the test gas having a high concentration can be detected by the color reaction base material of the same specification but also during storage. In that case, since it has a function of preventing the volatilization of the color reagent, 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 exposed to the test gas of the color reaction base material 4, or Even if it is formed and stored in a bag shape, the same effect is obtained.
[0016]
Further, in the above-described embodiment, hydrogen sulfide is targeted for detection. However, the same effect can be obtained even when applied to a target gas such as formaldehyde whose concentration in the measurement range is greatly different.
[Brief description of the drawings]
FIGS. 1A and 1B are an assembled perspective view and a cross-sectional view, respectively, showing an embodiment of a gas detection material of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the detection material of the present invention.
FIG. 3 is a cross-sectional view showing an embodiment of measuring means suitable for the detection material.
FIGS. 4A and 4B are a top view and a cross-sectional view, respectively, showing another embodiment of the present invention.
[Explanation of symbols]
1 Tab 2 Frame 3 Membrane 4 Color Reaction Base

Claims (5)

A color reaction base material on which a reaction reagent that performs a color reaction with a test gas is supported on a carrier; and a film having a prescribed ventilation resistance with respect to the test gas, and at least the color reaction base material A gas detection material constituted by laminating the film on the inflow surface side of the test gas so as to be peelable .   The gas detection material according to claim 1, wherein the film is made of a polymer film.   The gas detection material according to claim 1, wherein the film is silicon rubber or polyethylene.   The gas detection material according to any one of claims 1 to 3, wherein the membrane is subjected to a porous treatment.   The gas detection material according to claim 1, wherein the carrier is composed of a sheet having air permeability and containing silica gel at least on a reaction surface, and the reaction reagent is silver perchlorate and paratoluenesulfonic acid.

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