JP2003294593A - Gas detection method and gas detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a size of a device as a whole for lowering a production cost and to improve sensitiveness of gas absorption by an absorbent liquid in gas detection using a diffusion scrubber. <P>SOLUTION: In this detection method for detecting a specific gas by using an inner tube allowing permeation of the gas at least and an outer tube storing the inner tube inside, a rod body with a diameter smaller than the inside diameter of the inner tube is arranged inside the inner tube, while a liquid absorbing the specific gas is stored between the rod body and the inner tube wall. When air is introduced into a clearance between the inner tube and the outer tube, the specific gas is absorbed by the liquid for detecting existence and concentration of the gas. In this way, the device size can be reduced as a whole, a production cost can be lowered, and gas absorption sensitiveness by the absorbent liquid can be improved. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a specific substance contained in the air such as formaldehyde, acetaldehyde, ammonia, sulfur dioxide, hydrogen chloride, nitric acid, methylamine, carboxylic acid, nitrogen dioxide or hydrogen fluoride. The present invention relates to a method and an apparatus for detecting gas.

[0002]

2. Description of the Related Art Conventionally, as a device for detecting this type of gas, for example, a technique disclosed in Japanese Patent Laid-Open No. 10-90241 has been known, and such a device is generally a diffusion scrubber. It is called. The invention in this known gas analysis device and gas analysis method aims to suppress an increase in the number of parts of the device and obtain good responsiveness in a short measurement period when switching and measuring gas sampling points. It was done.

The specific construction of this diffusion scrubber is that an inner tube made of a gas permeable membrane tube is inserted inside the outer tube, and either the inner tube or the gap between the inner tube and the outer tube is inserted. Is used as the flow path of the absorption liquid of the analysis target gas, and the other flow path is used as the flow path of the analysis target gas to allow the absorption liquid to absorb the analysis target gas.

In the technique disclosed in Japanese Unexamined Patent Publication No. 10-90241, in order to collect the gas to be analyzed, pure water is stored as the absorbing liquid in a storage container and is continuously supplied to the diffusion scrubber by a liquid feed pump. Specifically, the absorption liquid is fed and introduced, and the gas to be analyzed is eluted by the eluent fed from a separately prepared storage container.

Further, the diffusion scrubber conventionally used has a length of about 1 m, and the entire device including the diffusion scrubber and an analyzer is a very large device, and is portable. It is not intended to be used.

[0006]

However, in the technique disclosed in Japanese Unexamined Patent Publication No. 10-90241, even if only the gas to be analyzed is simply collected, as described above, at least the storage container and the liquid transfer liquid. Since a pump is required, the entire apparatus becomes very large, and the cost required for manufacturing also increases, and because the absorption liquid does not have good sensitivity for absorbing the gas to be analyzed, There is a problem that it takes a lot of time for measurement.

Therefore, when gas is detected by the diffusion scrubber, there is a problem to be solved in that the size of the entire apparatus is reduced to reduce the cost required for manufacturing and the sensitivity of absorbing the gas with the absorbing liquid is improved. .

[0008]

As a concrete means for solving the above-mentioned problems of the conventional example, as the first invention according to the present invention, an inner tube through which at least gas can pass and the inner tube are arranged inside. A method of detecting a specific gas using an outer pipe, wherein a rod body having a diameter smaller than the inner diameter of the inner pipe is disposed inside the inner pipe, and the rod and the inner pipe wall A liquid that absorbs the specific gas is housed in the space, and air is introduced into the gap between the inner pipe and the outer pipe to allow the liquid to absorb the specific gas and detect the presence and concentration of the gas. The present invention provides a gas detection method characterized by:

In the first invention, the rod body is made of resin or glass as an additional requirement.

A second invention according to the present invention is an apparatus for detecting a specific gas, which uses at least an inner pipe through which a gas can permeate and an outer pipe having the inner pipe arranged therein.
Inside the inner pipe, a rod body having a diameter smaller than the inner diameter of the inner pipe is arranged, and means for storing a liquid for absorbing the specific gas between the rod body and the inner pipe wall, A gas detection device comprising means for introducing air into the gap between the inner tube and the outer tube, and means for causing the liquid to absorb the specific gas and detecting the presence and concentration of the gas. Is provided.

In the second invention, the rod body is made of resin or glass as an additional requirement.

In the gas detecting method according to the present invention, a rod is provided inside an inner tube through which a gas can permeate, and a liquid that absorbs a specific gas between the rod and the inner tube wall, that is, absorption. A liquid is stored, and air is introduced into the gap between the inner pipe and the outer pipe to allow the absorbing liquid to absorb a specific gas, that is, a target gas to be collected, and detect the presence and concentration of the gas. By doing so, the sensitivity of absorbing the gas with the absorbing liquid can be improved, so that the entire device can be downsized, the cost required for manufacturing can be reduced, and the existence of the specific gas can be reduced. And, it becomes possible to detect the concentration.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail based on specific embodiments. FIG. 1 shows a schematic sectional view of a gas detection device (diffusion scrubber) 1 according to the present invention. The gas detection device 1 is composed of an inner tube 2 through which a gas can pass and an outer tube 3, and the inner tube 2 is arranged inside the outer tube 3.

The inner tube 2 and the outer tube 3 are provided with holding members 4a and 4b.
Is held by. O-rings 5 are provided on both ends of each of the holding members 4a and 4b, and packings 6a, 6b, 6c, and 6d are screwed to the inside of the outer tube 3 from the outside of the gas detection device 1. Air is prevented from entering, and the gas detection device 1 further includes a sealing member 7
By disposing a and 7b, it is possible to prevent air from entering the inside of the gas detection device 1 from the outside.

The inner tube 2 is preferably made of, for example, a substantially transparent material such as Teflon (registered trademark) or polyethylene. The inner tube 2 is impermeable to liquid, but does not pass a gas to be collected. A plurality of holes are formed that are large enough to allow a part of the contained gas to pass therethrough, and are formed in a so-called porous shape.

A liquid (not shown) is housed inside the inner tube 2. The liquid is, for example, a container such as a vial,
Alternatively, the liquid stored in a connection tank 16 or the like, which will be described later, is stored in the containers through a liquid passage 9 formed in a connecting portion 8 arranged at one end of the gas detection device 1, and then, The liquid passage 9 is sealed by closing it with a lid or the like not shown. Further, the inner tube accommodating the liquid may be formed into a so-called cartridge so that it can be removed and replaced.

The liquid is a gas to be collected,
That is, it is a liquid (absorption liquid) that can absorb (dissolve) a specific gas, and the liquid can absorb the gas by the permeation of the gas from the inner tube 2.

Examples of the liquid include pure water, a 0.5% boric acid aqueous solution (AHTM method), a triethanolamine aqueous solution (pararosarinine method), a 0.5% phosphoric acid aqueous solution (indophenol method), and sulfanilic acid. An naphthylethylenediamine acetic acid aqueous solution (Salzmann method) or a 0.1 M sodium hydroxide aqueous solution or other gas absorbing solution defined by an official method can be used.

By using these pure water, or an absorbing solution of gas specified by the official method, etc., for example, formaldehyde, acetaldehyde, ammonia, sulfur dioxide, hydrogen chloride, nitric acid, methylamine, carboxylic acid, dioxide It can absorb gases such as nitrogen or hydrogen fluoride.

As the outer tube 3, for example, a glass tube or the like is preferably used. One end of the outer tube 3 is provided with an air suction port 10 and the other end is provided with the air introduction port 11. . When sucking air from the suction port 10, the suction port 10
It is possible to connect a hose or the like (not shown) to the hose nipple 12 disposed in the above, and suck air through the hose by a suction pump or the like (not shown) to introduce air from the inlet 11.

The inlet 11 has a hose nipple 13
The hose nipple 13 is provided in this case.
By connecting a hose or the like (not shown) to the air, it is possible to introduce air at a location apart from the gas detection device 1. When the air around the gas detection device 1 is introduced, the hose nipple 13 is not always necessary because the introduction port 11 is simply provided, and the introduction port 11 is essentially a suction port. 10
It suffices if one or more are formed on the other end side.

By sucking through the suction port 10 in this way, the air introduced through the introduction port 11 is introduced into the gap between the inner tube 2 and the outer tube 3. At this time, as described above, a part of the gas containing the gas to be collected permeates the inside of the inner pipe 2, so that the gas to be collected to be collected inside the inner pipe 2 is removed. The absorbing liquid can absorb the gas, and the gas can be collected.

In this way, the air is introduced into the gap between the inner tube 2 and the outer tube 3 instead of inside the inner tube 2, so that the area where the liquid comes into contact with the gas through the inner tube 2 Therefore, the sensitivity (absorption rate) of the liquid absorbing the gas can be increased.

Further, when a certain amount of air is sucked from the suction port 10, the suction force is made small, that is, the air is slowly sucked so that the air is separated from the inner tube 2 and the outer tube 3 by a gap. It is possible to increase the sensitivity (absorption rate) of the liquid absorbing the gas by increasing the time during which the specific gas is in contact with the liquid as the time of introduction into the liquid increases. become.

In the gas detector 1 according to the present invention, the rod 14 having a diameter smaller than the inner diameter of the inner pipe 2 is arranged inside the inner pipe 2. It is preferable to use, for example, a resin or glass rod as the rod 14.

In this way, by disposing the rod 14 inside the inner pipe 2 and storing the liquid for absorbing the specific gas between the rod 14 and the wall of the inner pipe 2, Although the amount of the liquid stored inside 2 decreases, the amount of the gas absorbed by the liquid is substantially the same because the area of contact between the liquid and the specific gas is the same. Therefore, the sensitivity of the liquid absorbing the gas can be substantially increased.

Therefore, by disposing the rod 14 inside the inner tube 2, the amount of the liquid can be reduced, and the sensitivity of the liquid to absorb the gas can be increased, so that the entire apparatus can be obtained. Even if the size is reduced, it is possible to maintain the same measurement accuracy as that of a large measuring device, so that it is possible to reduce the size of the entire device, which allows the device to be downsized and the storage container and liquid transfer Since it is not necessary to use a pump, the manufacturing cost can be reduced, and the cost due to the reduced amount of the liquid can be reduced.

Further, by increasing the sensitivity of the liquid to absorb the gas, the amount of suction of air can be reduced, and by reducing the size of the entire apparatus, the air can be sucked slowly as described above. Even in such a case, since the suction amount is small and the device is small, the suction time can be shortened, that is, the time for collecting the specific gas can be shortened.

When the suction amount of air is the same, the gap between the inner tube 2 and the outer tube 3 is narrowed,
Since the area in which the liquid comes into contact with the gas via the inner tube 2 can be increased with respect to the suction amount of air, the sensitivity of the liquid absorbing the gas can be further increased. It will be.

A gas detecting device 1 for explaining a method of transferring the liquid from the gas detecting device 1 to the container 15.
A schematic cross-sectional view of the container and the vial 15 is shown in FIG. The container 15 may be a container that stores the liquid before the liquid is stored in the inner tube 2,
When the container containing the liquid is used as described above, the contamination of the liquid can be prevented.

As shown in FIG. 2, the gas detector 1 is turned upside down with the transfer connection tank 16 and the container 15 arranged in the liquid passage 9 in the gas detector 1. The liquid 17 can be easily transferred and stored in the container (vial bottle) 15. Further, instead of the connection tank 16, a tube such as Teflon (registered trademark) may be simply connected and the liquid 17 may be transferred.

FIG. 3 is a schematic sectional view of the simple colorimeter 18 for explaining a method of detecting the presence and concentration of the specific gas absorbed in the liquid by using the simple colorimeter 18.
Shown in. As shown in FIG. 3, the container 15 accommodating the liquid 17 in which the specific gas is collected is placed in the simple colorimeter 18 and the lid 19 is covered. At this time, the liquid is colored by preliminarily placing a reagent or the like that develops color in the gas in the container 15, or by adding it during measurement.

The simple colorimeter 18 includes, for example, an LED 20.
And a light sensor 21 are arranged, and the light of the LED 20 is transmitted through the container 15 to the colored liquid, and the transmitted light is read by the light sensor 21,
The presence and concentration of the particular gas can be detected. Therefore, the container 15 is preferably made of a transparent material,
For example, it is preferable to use a vial bottle or a transparent glass container.

The simple colorimeter 18 may be a commonly used simple colorimeter or may be manufactured according to the size of the container 15. Also, the optical sensor 2
For example, CdS or the like can be used as 1.

As described above, by detecting (measuring) the presence and concentration of the specific gas by using the simple colorimeter 18, the container 15 containing the liquid is collected instead of being brought back for measurement. Since the measurement can be performed immediately on site, the measurement is simple, and since there is almost no change with time of the liquid, the measurement error is small.

Incidentally, the external dimensions of the gas detection device 1 according to the present invention are about 150 mm in length and about 18 m in diameter.
Since it is about m, it is convenient to carry and a plurality of kinds of gases to be sampled at the same site can be sampled at the same time.

[0037]

As described above, the gas sampling method according to the first aspect of the present invention uses at least the inner tube through which the gas can permeate and the outer tube in which the inner tube is arranged. Is a method of detecting the gas of,
A rod body having a diameter smaller than the inner diameter of the inner pipe is arranged, and a liquid for absorbing the specific gas is housed between the rod body and the inner pipe wall, and the liquid is absorbed in the gap between the inner pipe and the outer pipe. By introducing air and causing the liquid to absorb the specific gas and detecting the presence and concentration of the gas, the sensitivity of absorbing the gas with the absorbing liquid can be improved and the size of the entire device can be reduced. It is possible to reduce the manufacturing cost of the device, reduce the amount of liquid absorbing a specific gas, and detect the presence and concentration of the specific gas in a short time. It has an excellent effect.

The gas detecting device according to the second aspect of the present invention is a device for detecting a specific gas using at least an inner tube through which a gas can permeate and an outer tube in which the inner tube is arranged. A rod having a diameter smaller than the inner diameter of the inner pipe is disposed inside the inner pipe, and a liquid for absorbing the specific gas is housed between the rod and the inner pipe wall. Means and
Means for introducing air into the gap between the inner tube and the outer tube,
By providing the liquid with the means for absorbing the specific gas and detecting the presence and concentration of the gas, it is possible to improve the sensitivity of absorbing the gas with the absorbing liquid and reduce the size of the entire apparatus. The manufacturing cost of the device can be reduced, and since the device is small, it can be carried, and therefore, an excellent effect that a plurality of kinds of gases to be sampled at the same site can be sampled simultaneously can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a gas detection device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing a gas detection device and a container for explaining a method of transferring a liquid from the gas detection device to the container.

FIG. 3 is a cross-sectional view schematically showing a simple colorimeter for measuring the amount of a specific gas collected by a liquid stored in the container.

[Explanation of symbols]

1 Gas detector (diffusion scrubber) 2 inner tube 3 outer tube 4a, 4b holding member 5 O-ring 6a, 6b, 6c, 6d packing 7a, 7b Sealing member 8 connection 9 liquid path 10 Suction port 11 entrance 12, 13 Hose nipple 14 rods 15 containers (vials) 16 connection tank 17 liquid 18 Simple colorimeter 19 lid 20 LED 21 Optical sensor

Continued front page    (72) Inventor Shigeru Tanaka             Kei, 3-14-1, Hiyoshi, Kohoku Ward, Yokohama City, Kanagawa Prefecture             Faculty of Science and Technology, University of Tokyo (72) Inventor Kazuo Konno             6431 Fukaya, Ayase City, Kanagawa Prefecture Gaste Co., Ltd.             In the dock (72) Inventor Yumi Arimoto             6431 Fukaya, Ayase City, Kanagawa Prefecture Gaste Co., Ltd.             In the dock F-term (reference) 2G052 AA01 AA03 AB01 AB06 AB07                       AB11 AD02 DA01 FD09 GA11                       JA13 JA16                 2G054 AA01 BA10 BB01 EA06 FA06                       FA32 FA33

Claims (4)

[Claims] 1. A method for detecting a specific gas using at least an inner tube permeable to a gas and an outer tube having the inner tube disposed therein, wherein the inner tube is A rod having a diameter smaller than the inner diameter of the pipe is arranged, a liquid for absorbing the specific gas is stored between the rod and the inner pipe wall, and air is introduced into the gap between the inner pipe and the outer pipe. A method for detecting gas, which is characterized in that the liquid is made to absorb the specific gas to detect the presence and concentration of the gas. 2. The gas detecting method according to claim 1, wherein the rod body is made of resin or glass. 3. A device for detecting a specific gas using at least an inner tube permeable to gas and an outer tube having the inner tube disposed therein, wherein the inner tube is A rod having a diameter smaller than the inner diameter of the pipe is arranged, and means for accommodating the liquid for absorbing the specific gas is provided between the rod and the inner pipe wall, and a gap between the inner pipe and the outer pipe. A gas detecting apparatus comprising: a means for introducing air; and a means for causing the liquid to absorb the specific gas and detecting the presence and concentration of the gas. 4. The rod body is made of resin or glass.
The gas detection device described in 1.