JP2003287481A - Gas dilution apparatus and method for diluting gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for using a simple instrument and surely diluting a gas with a relatively low dilution ratio. <P>SOLUTION: A step for activating a means for pushing out the gas, pushing out a predetermined quantity of the gas into a closed container and pushing out the predetermined quantity of the gas from a gas dilution container outside the closed container by using one of two external coupling openings and a step for activating a means for pulling in the gas, pulling in the predetermined quantity of the gas from the closed container and pulling in the predetermined quantity of the gas into the gas dilution container by using one of two external coupling openings are combined. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a technique for diluting a gas simply and surely.

[0002]

2. Description of the Related Art The prior art is as follows.

Constant flow rate dilution method This is a method of continuously mixing a sample gas and a dilution gas at a constant flow rate ratio.

An example is the gas mixer described in Japanese Patent Laid-Open No. 2001-349821.

This method requires a large amount of gas to be measured.

Quantitative dilution method A method in which a known amount of diluting gas is put in a plastic film bag and a sample gas collected by a gas tight syringe is introduced from a cock attached to the plastic film bag.

[0007] This method is convenient when the dilution ratio is usually large, such as about one-hundredth or more, but it is not suitable when the dilution ratio is small due to the size limit of the gas-tight syringe.

[0008]

When measuring the gas concentration with various gas concentration analyzers, if the measured gas concentration is high, for example, above the upper limit of measurement, it is necessary to dilute it at a relatively low magnification.

At this time, when a large amount of gas to be measured can be supplied, a conventional diluent gas (for example, pure nitrogen gas or pure air filled in a cylinder) and the gas to be measured are mixed at a constant flow rate ratio. It becomes possible to measure by using the constant flow rate dilution method.

However, when the amount of gas to be measured is limited, particularly when the gas is supplied in a plastic film bag, it may be difficult to use the constant flow dilution method which requires a large amount of sample gas. is there.

In addition, in many cases, the required dilution ratio is too small to apply the quantitative dilution method.

According to the present invention, when the amount of gas required for measurement is relatively small or the amount is limited, the gas is diluted stepwise at a low magnification of, for example, about 9/10 to 1/20. It aims to provide the technology for.

Still another object and advantage of the present invention are:
It will be apparent from the following description.

[0014]

According to the present invention, a gas dilution container, a closed container for accommodating the gas dilution container,
Connecting the gas dilution container and the outside of the closed container 2
Provided is a gas diluting device having two external connection ports, a gas pushing-out means having the ability to push a predetermined amount of gas into the closed container, and a gas drawing-in means having the ability to draw a predetermined amount of gas from the closed container. .

Further, according to the present invention, there is provided a gas diluting method using such a gas diluting device, in which a gas pushing means is actuated to push a predetermined amount of gas into a hermetically sealed container, and the gas is attached thereto. Then, using one of the two external connection ports, a predetermined amount of gas is supplied from the gas dilution container,
The step of pushing out of the closed container and actuating the gas drawing means draws a predetermined amount of gas from the inside of the closed container, and incidentally, using one of the two external connection ports, A method of diluting a gas is provided, including the step of drawing a predetermined amount of gas into the gas dilution container.

With these devices and methods, it is possible to dilute a gas at a low dilution ratio.

It is preferable that a stirring element separate from the driving device can be installed in the gas dilution container.

The gas pushing means and / or the gas drawing means preferably has a gas pump and a flow meter.

This is because the gas with a low dilution ratio can be diluted easily.

Further features of the present invention will be clarified in the following embodiments and drawings of the invention.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that these drawings and the like and the description only illustrate the present invention and do not limit the scope of the present invention. It goes without saying that other embodiments may belong to the scope of the present invention as long as they match the gist of the present invention.

A gas dilution container according to the present invention, a closed container for housing the gas dilution container, and two external connection ports for connecting the gas dilution container and the outside of the closed container.
FIG. 1 exemplifies the configuration of a gas diluter having a gas pushing means having the ability to push a predetermined amount of gas into the closed container and a gas drawing means having the ability to draw a predetermined amount of gas from the closed container.

In FIG. 1, a gas dilution container 1 is installed in a closed container 2.

The closed container 2 has a gas outlet 3 and a gas inlet 4 for pushing out and drawing in the gas in the gas dilution container 1.

The gas discharge port 3 and the gas suction port 4 are respectively provided with a gas discharge pump 5 which is an example of gas discharge means, a flow meter 6, and a gas suction pump 7 which is an example of gas suction means. The flow meter 8 is connected.

The closed container 2 is also provided with an external connection port 10 having a cock 9 and an external connection port 12 having a cock 11. The external connection ports 10 and 12 are preferably pipe-shaped as shown in FIG. 1 in order to facilitate connection with the gas dilution container 1 and the like.

The gas dilution container 1 contains the sample gas, and 2
Have more than one cock. In FIG. 1, it has a cock 13 and a cock 14.

The gas dilution container 1 is connected to the outside using plastic tubes 16 and 17 through connection ports 10 and 12 provided with cocks 13 and 14, respectively.

The dilution gas can be supplied from the external connection port 12 at atmospheric pressure. For example, cock 21
The plastic film bag 23 having the above is filled with a diluting gas, and the plastic tube 19 is connected to the external connection port 12.

The stirrer 15 is previously placed in the gas dilution container 1, and the stirrer 24 installed at the lower part of the closed container 2 is operated to mix the gas in the gas dilution container 1. Since gas agitation is often performed in a plastic film bag as shown in FIG. 1, it is preferable that the agitator is separated from the drive motor and the like. For example, a combination of a magnetic stirrer and a plastic or glass stirrer enclosing a magnet is suitable.

The external connection port 10 is connected to a plastic film bag 22 having a cock 20 via a plastic tube 18, for example. The plastic film bag 22 functions as a diluent gas collection container. The sizes of the plastic film bags 22 and 23 can be arbitrarily selected.

The external connection port 10 and the external connection port 12 may be compatible with each other, and one can be used as both.

With such a structure, the gas pushing out means is operated to push out a predetermined amount of gas into the closed container, and in association therewith, one of the two external connection ports is used,
A step of pushing out a predetermined amount of gas from the gas diluting container to the outside of the closed container and operating the gas drawing means to draw in the predetermined amount of gas from the inside of the closed container.
According to FIG. 3, the procedure for carrying out the gas dilution method including the step of drawing a predetermined amount of gas into the gas dilution container using any one of the two external connection ports can be illustrated as follows according to FIG.

1. 1000 mL according to step S1
The gas dilution container 1 containing the sample gas is placed in the closed container 2, and as shown in FIG.
Connect with 3. Empty the plastic film bag 22,
The plastic film bag 23 is filled with a diluent gas.

2. According to step S2, the cock 11 is closed and the cocks 9, 13, 14, 20, 21 are opened. The stirrer 24 is activated and the stirring bar 15 is activated.

3. According to step S3, the gas pushing pump 5 is operated to push air into the closed container 2 from the gas outlet 3 at 100 mL / min for 1 minute, for example. This flow rate is measured by the flow meter 6. Then, 100 mL of gas is extruded from the gas dilution container 1 into the plastic film bag 22.

According to the present invention, the same amount of gas as the amount of gas pushed into the closed container 2 by the gas pushing pump 5 as described above is pushed from the gas dilution container 1 to the plastic film bag 22. However, this is because a container such as a plastic film bag is used as the gas dilution container 1, and an increase in the internal pressure of the closed container 2 immediately acts as a driving force for moving the gas from the gas dilution container 1 to the plastic film bag 22. This is because

Therefore, as the gas dilution container 1, a rigid container is not suitable.

On the contrary, the closed container 2 must have rigidity and its volume must not be changed by the gas pushing out by the gas pushing pump 5.

The same applies to the relationship between the gas drawing by the gas drawing pump 7 and the gas dilution container 1 and the closed container 2.

At this stage, the gas stored in the plastic film bag 22 is undiluted, but the gas concentration may be analyzed if necessary.

If not necessary, no analysis is performed, and step S
After step 1, it may jump to step S5. However, in that case, since it will be diluted to 1000 mL,
It will be slightly different from the following dilution ratio.

4. According to step S4, the plastic film bag 22 is replaced with an empty one.

5. According to step S5, the cock 9 is closed and the cocks 11, 13, 14, 20, 21 are opened.
The stirrer 24 is activated and the stirrer 15 remains activated.

6. According to step S6, the gas drawing pump 7 is operated to draw air from the gas inlet 4 at a rate of 100 mL / min for 1 minute from the closed container. The amount of drawing is measured by the flow meter 8. Then, 100 mL of the dilution gas in the plastic film bag 23 enters the gas dilution container 1. The stirring bar 15 makes the gas concentration in the gas dilution container 1 uniform. As a result, it is possible to prepare a diluent gas having 90% by volume of the initial concentration of the sample gas.

7. The above steps S2 and S3 are repeated.
The gas stored in the plastic film bag 22 at this stage is 90% by volume of the dilution gas. If necessary, analyze the gas concentration.

8. When further diluting, the above step S
Repeat from 4 onwards.

The type of diluent gas that can be used in the present invention can be appropriately selected according to the type of sample gas.

In general, nitrogen or argon is inert and a high purity one is easily obtained at a low cost, so that it is often suitable as a diluting gas.

Further, in the above example, the gas pushing pump is illustrated as the constituent element of the gas pushing means, and the gas drawing pump is exemplified as the constituent element of the gas drawing means. It is also possible to use such means. By adopting a method such as switching the pipes, it is possible to use both the gas pushing means and the gas drawing means.

As the flowmeter, any known flowmeter can be used as long as it does not violate the gist of the present invention. An integrated flow meter may be used.

The plastic film bag used above may be of any type as long as it does not violate the gist of the present invention, but it is preferable that it has a low gas permeability and at least an inner gas adsorbing property. Examples of such a material include those made of vinyl fluoride (Tedlar bag made by DuPont), tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-vinyl acetate copolymer (Kuraray Co., Ltd., Eval). Etc. can be mentioned.

It is desirable to give similar consideration to the plastic tube used for connection, but it is often not necessary to be so strict.

Further, in the above description, the number of external connection ports for connecting the gas dilution container and the outside of the closed container is set to two, but the number of external connection ports is not excluded in the present invention. For example, it is also within the scope of the present invention to set the number of external connection ports to three or more for the case where it is desired to collect gas in two or more plastic film bags at one time.

In FIG. 2, starting from 1000 mL of sample gas, the amount of extrusion / pull-in gas is 100 to 40.
The gas concentration given at each dilution step when repeatedly diluted is shown as 0 mL. Initial concentration is 1000 volume pp
The value was calculated as m.

According to the present invention, the dilution as shown in FIG. 2 can be surely performed.

Further, according to the present invention, when the amount of gas required for measurement is relatively small or the amount is limited, the present invention is stepwise, for example, at a low magnification of about 9/10 to 1/20. Can be diluted. However, dilution ratios outside this range are not excluded. Further, when the amount of gas required for measurement is relatively small, or when the amount is limited, it is possible to cite the case of an amount on the order of liters, but the present invention is not limited to this. It goes without saying that the present invention can be applied to the case of other amounts unless it goes against the gist of the present invention.

Further, as can be seen from the above example, in the present invention, there are few problems such as contamination of the sample gas and adsorption of the sample gas to the instrument used.

Further, in the present invention, the above-mentioned dilution can be automatically performed by automating the movements of the gas pushing means, the gas drawing means, the valve, the cock and the like.

The present invention evaluates the corrosive gas resistance of electronic devices, the design of materials / parts, the quality control, the acceptance inspection department, which is used for hermetic precision electronic devices such as magnetic disk devices. Inspection department to evaluate exposure with concentration gas, manufacture electronic equipment such as semiconductor device, liquid crystal device, magnetic disk equipment, analyze and remove chemical pollutants in clean room, quality control department and building construction company, and further , Evaluate harmful gases from building construction related companies and organic materials (adhesives, rubber, resins, wall materials, etc.) that develop materials that reduce harmful gases (sick house causative substances) generated from building materials for general houses It can be widely used for the purpose of diluting gas in analysis institutions, certification of environmental gas resistance evaluation test gas, automobile exhaust gas tests, exhaust gas tests, etc. It is believed that it is.

In particular, this apparatus is used for various evaluations for examining the change in characteristics by changing the concentration, for example, corrosion resistance evaluation of electronic equipment,
It is also useful as a method for preparing a gas having a concentration series for evaluating the adsorption capacity of a clean room gas breathing filter.

[0062]

EFFECT OF THE INVENTION It is possible to surely dilute a gas having a relatively low dilution ratio with a simple instrument. Moreover, multi-step dilution can be easily performed. There are few problems of sample gas contamination and adsorption to equipment used.

[Brief description of drawings]

FIG. 1 illustrates the configuration of a gas diluter according to the present invention.

FIG. 2 shows a mode of stepwise dilution of gas.

FIG. 3 is a flowchart showing a procedure of stepwise dilution of gas.

[Explanation of symbols] 1 gas dilution container 2 closed container 3 gas outlet 4 gas inlet Pump for 5 gas extrusion 6,8 Flowmeter 7 Gas intake pump 9, 11, 13, 14, 20, 21 cock 10, 12 External connection port 15 Stirrer 16, 17, 18, 19 plastic tubes 22,23 Plastic film bag 24 Star

Continued front page    F term (reference) 2G052 AD22 DA13 DA22 FB07 FD01                       JA04 JA08

Claims (4)

[Claims] 1. A gas dilution container, a closed container for housing the gas dilution container, and a connection between the gas dilution container and the outside of the closed container.
A gas diluting device having one external connection port, a gas pushing means having the ability to push a predetermined amount of gas into the closed container, and a gas drawing means having the ability to draw a predetermined amount of gas from the closed container. 2. The gas diluting device according to claim 1, wherein a stirring element separate from the driving device can be installed in the gas diluting container. 3. The gas diluting device according to claim 1, wherein the gas pushing means and / or the gas drawing means has a gas pump and a flow meter. 4. A method for diluting a gas using the gas diluting device according to any one of claims 1 to 3, wherein a predetermined amount of gas is activated by activating the gas pushing means.
Extruded into the closed container, and incidentally using either of the two external connection ports, from the gas dilution container,
A step of pushing out a predetermined amount of gas to the outside of the closed container, activating the gas drawing means to supply a predetermined amount of gas,
A method of diluting a gas, the method comprising: withdrawing from the inside of the closed container, and incidentally, drawing a predetermined amount of gas into the gas dilution container using one of the two external connection ports.