JPH09170970A - Standard gas dilution apparatus, standard gas generation apparatus and liquid sample container for generation of standard gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly accurate low-concentration standard gas even when a dilution part has a small number of steps. SOLUTION: A standard gas fed to an entrance of a flow rate controller 4 and discharged out from an exit is supplied to a main flow path 24. A dilution gas is supplied to the main flow path 24 from a first branch 26 and a third branch path 28 which are branched from the main flow path 24 and closer in this order to the flow rate controller 4. A part of the gas in the main flow path 24 is discharged through a second branch 27. Flow rates of the supplied and discharged gases are controlled by flow rate controllers 29, 30, 31 installed in the middle of the branches 26, 27, 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a standard gas diluting device for diluting a standard gas into a low-concentration standard gas, a standard gas generating device for generating a standard gas from a liquid sample, and a standard gas generating device usable therefor. The present invention relates to a liquid sample container.

[0002]

2. Description of the Related Art A standard gas is used for calibration of various gas analyzers and the like, and has been conventionally used as a low-concentration standard gas generator for generating a low-concentration standard gas from a liquid sample. The standard gas adjusting device disclosed in the publication is known.

This conventional low-concentration standard gas generating device (standard gas adjusting device) is a standard gas generating part for generating a relatively high-concentration standard gas from a liquid sample, and a standard gas generated by the standard gas generating part. And a standard gas diluting device that dilutes the standard gas with a low concentration standard gas. In the standard gas generating unit, a pressure regulator, a flow rate controller, and a sample chamber containing a liquid sample container having a hole containing a liquid sample are arranged in this order along the gas flow in the middle of one-way gas pipe. It was done. The standard gas diluting device has a vapor sample supply channel directly connected to the standard gas generation section and four branch pipes branched from the vapor sample supply channel. The first and third branches are connected to a gas outlet in which a flow controller is arranged, and the second and fourth branches are connected to a gas inlet in which a pressure regulator and a flow controller are arranged in this order along the flow of gas. It is a thing.

According to the standard gas diluter used in this conventional low-concentration standard gas generator, the liquid sample concentration in the standard gas supplied from the standard gas generator to the standard gas diluter is C '. , The flow rate of the standard gas supplied from the standard gas generation unit to the standard gas diluter is L1 ′,
The flow rate of the gas discharged from the branch is L2 ′, the flow rate of the gas supplied from the second branch is L3 ′, the flow rate of the gas discharged from the third branch is L4 ′, the gas supplied from the second branch. When the flow rate of L5 ′ is L5 ′, the flow rate L1′−L2 ′ + L3′−
L4 ′ + L5 ′, concentration C ′ · [(L1′−L2 ′) /
(L1'-L2 '+ L3')] [[L1'-L2 '+
L3'-L4 ') / (L1'-L2' + L3'-L4 '
+ L5 ′)] low-concentration standard gas is obtained, and a low-concentration standard gas in the ppb region is obtained.

In the standard gas diluter used in the conventional low-concentration standard gas generator, the vapor sample supply passage has no flow rate controller or the like as a source of background or coexisting interfering substances. Since it is not provided, a low-concentration standard gas can be obtained with a highly accurate concentration.

Further, the liquid sample container used in the conventional low-concentration standard gas generator is integrally formed of a glass material.

[0007] Conventionally, as a gas source of a relatively high-concentration standard gas, a cylinder containing a standard gas whose concentration is adjusted in advance with high accuracy is often used.

[0008]

However, in the standard gas diluting device used in the conventional low-concentration standard gas generator, the dilution ratio of the first-stage diluting section consisting of the first branch and the second branch is (L1'-L2 ') / (L1'-L
2 '+ L3'), so to obtain a high dilution rate,
L1'-L2 '(that is, the difference between the flow rate L1' of the standard gas from the standard gas generating portion and the flow rate L2 'of the gas exhausted from the first branch) must be reduced. But,
It is very difficult to accurately reduce L1′-L2 ′. That is, since the vapor sample supply channel is directly connected to the standard gas generation unit, the flow rate of the gas flowing through the sample chamber is L1 ′ as it is, so L1 ′ must be increased to some extent. In order to make L2 'small, L2' must be made large, but if L2 'is made large, the variation of L2' becomes large according to the accuracy of the flow rate controller for controlling to L2 '.
It is very difficult to reduce 1′-L2 ′ with high accuracy. If the flow rate of the gas flowing through the sample chamber is not large to some extent, the evaporation amount of the liquid sample in the liquid sample container becomes unstable. Therefore, in the standard gas diluter used in the conventional low-concentration standard gas generator,
It was not possible to obtain a high dilution rate, and it was not possible to obtain a low-concentration standard gas in the ppt region with a highly accurate concentration. L1 '
It is conceivable to increase the number of branches and provide three or more dilution sections without reducing -L2 ', but in that case, the number of constituent elements increases and the cost increase cannot be avoided. In addition, since the accuracy of the concentration must be deteriorated accordingly when the number of stages of the dilution section is increased, there is a certain limit to the number of stages of dilution, so that the conventional low-concentration standard gas generator is used. After all, in the standard gas diluter, ppt with high precision concentration
It was not possible to obtain a low-concentration standard gas in the region.

Further, in the conventional low-concentration standard gas generator, the standard gas generator is directly connected to the vapor sample supply passage of the standard gas diluter, so that the standard gas diluter is used to generate the standard gas. It was possible to dilute only one type of standard gas generated from the liquid sample at the generation part. Therefore, for example, when diluting a standard gas having a relatively high concentration prepared in advance (for example, a standard gas contained in a cylinder) instead of the standard gas of a liquid sample, the conventional low concentration standard is used. A standard gas diluting device for diluting the standard gas must be prepared separately from the gas generator, which is extremely uneconomical.

Further, the liquid sample container used in the standard gas generating part of the conventional low-concentration standard gas generator is
As described above, since the glass material is integrally formed, it requires skill and labor for manufacturing, and the cost is inevitable. Since the liquid sample container is integrally formed of a glass material, the size and thickness of the holes formed in the liquid sample container cannot be accurately adjusted to a desired size and thickness, and thus the liquid sample container was manufactured. Calibration must be performed for each perforated container (calibration by measuring the reduction amount of the liquid sample in the liquid sample container with a precision balance when a constant flow rate of gas is kept flowing for a long time). It required a great deal of effort. Furthermore, since the liquid sample container is integrally formed of a glass material, when the liquid sample is taken in and out of the liquid sample container, it is performed from the hole of the liquid sample container. In order to obtain a standard gas having a low dynamic concentration, the holes of the liquid sample container are made small, so that it takes a great deal of effort to take the liquid sample in and out of the liquid sample container. Even if a device such as an injection needle is used, if the hole of the liquid sample container is too small, the liquid sample cannot be taken in and out of the liquid sample container, so the size of the hole of the liquid sample container should be small. There is a certain limit to this. For this reason,
There is also a limit to how low the concentration of the standard gas generated in the standard gas generating section is.

The liquid sample container used for generating the standard gas is, for example, a device described in JIS-K0226 (a device used for mixing liquid sample (water) vapor of known concentration in gas). As is clear from the fact that the container with a diffusion tube that is a liquid sample container with holes used in (1) is also made of glass material, it should be made of glass material. It was the conventional technical common sense in the field.

Further, as described above, a cylinder containing a standard gas whose concentration has been adjusted in advance with high precision is often used as a gas source of a relatively high-concentration standard gas. It takes a great deal of effort to manufacture a gas-filled cylinder, and this cylinder is very expensive. Also,
For example, special handling is required for storage so that water in the standard gas is not adsorbed on the inner wall of the cylinder, and even if such handling is performed, the concentration of the standard gas will change over time. The life of the cylinder gas was short.

The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a low-concentration standard gas with a highly accurate concentration even when the number of stages of the diluting section is small, and ppt. It is an object of the present invention to provide a standard gas diluting device capable of obtaining an extremely low standard gas concentration in a region and a low concentration standard gas generating device using the standard gas diluting device.

Another object of the present invention is to provide a standard gas diluting device capable of diluting different kinds of standard gas with one standard gas diluting device and a low concentration standard gas generating device using the standard gas diluting device. .

Yet another object of the present invention is that it is easy and inexpensive to manufacture, does not require calibration for all individual items, and that it is easy to put in and take out a liquid sample and generates a low-concentration standard gas. It is an object of the present invention to provide a liquid sample container for standard gas generation that can also be used, and a standard gas generator using the same.

Still another object of the present invention is to provide a standard gas generator which is an inexpensive and easy-to-use alternative to the standard gas cylinder.

[0017]

In order to solve the above problems, a standard gas diluting device according to a first aspect of the present invention has a main inlet and a main outlet, and a standard gas introduced into the main inlet is provided. In a standard gas diluting device for diluting into a low-concentration standard gas and flowing out from the main outlet, a first flow controller having an inlet connected to the main inlet and one end connected to an outlet of the first flow controller. The main flow path has the other end connected to the main flow outlet, and one or more branch paths branched from the main flow path. Of the one or more branch passages, the odd-numbered branch passages closer to the first flow rate controller are air supply passages for supplying the main passage with dilution gas, and This is the air supply passage in which the flow controller is installed. Of the one or more branch passages, the even-numbered branch passages closer to the first flow rate controller are exhaust passages for exhausting gas from the main flow passage, and the flow rate controller is installed on the way. It is an exhaust path.

In the standard gas diluting device according to the first aspect, the first flow controller controls the flow path between the main inlet and the main outlet (the vapor sample supply in the standard gas diluting device of the conventional standard gas generator described above). Corresponding to the flow path), the first flow controller and the first branch path from the one closest to the flow controller serve as the first-stage dilution section, and the dilution ratio of the first-stage dilution section is , The flow rate of the gas flowing from the outlet of the above-mentioned first flow rate controller to the main flow path is L
If the flow rate of the gas supplied from the first and first branch paths is L2, then L1 / (L1 + L2). The second and subsequent branch passages from the side closer to the first flow rate controller (however, the second and subsequent branch passages are not necessarily required) are used in the conventional low-concentration standard gas generator described above. It has the same function as that of the third branch of the standard gas generator and thereafter, constitutes the second and subsequent dilution sections, and has the same dilution rate. Since the dilution rate of the first-stage dilution section is L1 / (L1 + L2), the gas flow rate L1 by the first flow rate controller can be accurately reduced. It is possible to accurately reduce the dilution rate of, so that even if the number of stages of the dilution section is small, a highly accurate dilution rate can be obtained as a whole, and a low-concentration standard gas can be obtained with a highly accurate concentration. For example, it becomes possible to obtain an extremely low-concentration standard gas in the ppt region.

In the standard gas diluter used in the conventional low-concentration standard gas generator, the flow path between the main inlet and the main outlet serves as a source of background and coexisting interfering substances. It was an attempt to obtain a low-concentration standard gas with a highly accurate concentration by not providing a flow rate controller or the like. However, according to the research conducted by the present inventors, even if background or coexisting substances are generated on the side close to the main inlet, the concentration of the standard gas is high on the side close to the main inlet, so that the amount of the sample in the gas is large. The amount of background and coexisting interfering substances is negligible with respect to the amount of, and the background and coexisting interfering substances do not substantially affect the accuracy of the final concentration of low-concentration standard gas. There was found. Therefore, the first
The first flow controller is provided on the side closest to the main inlet, and the first flow controller is provided between the outlet and the main outlet of the first flow controller. Since the main flow path is not provided with a flow controller or the like which is a source of background and coexistence interfering substances, a low-concentration standard gas can be obtained with high accuracy.

The standard gas diluting device according to a second aspect of the present invention is the standard gas diluting device according to the first aspect, wherein a plurality of standard gas supply passages for supplying different standard gases and a plurality of the standard gas diluting devices are provided. Switching means for switching the gas supply passage so that only one of the gas supply passages communicates with the main inlet of the standard gas diluting device.

With the standard gas diluting device according to the second aspect, not only the low-concentration standard gas can be obtained with high accuracy even if the number of stages of the diluting section is small, but a plurality of standard gas supply passages are also provided. Since it is equipped with a switching means, it is possible to dilute different kinds of standard gas with one standard gas diluting device without separately using the standard gas diluting device, which is economical.

The standard gas diluting device according to the third aspect of the present invention has a main inlet and a main outlet, and dilutes the standard gas introduced into the main inlet into a low-concentration standard gas and flows out from the main outlet. In the standard gas dilution device, a plurality of standard gas supply passages for supplying different standard gases and the plurality of standard gas supply passages are switched, and only one of them is used as the main stream of the standard gas dilution device. And a switching means for communicating with the entrance.

According to the standard gas diluting device of the third aspect, since a plurality of standard gas supply passages and switching means are provided, one standard gas diluting device can be used without separately using the standard gas diluting device. It is economical because different types of standard gas can be diluted by the device. In the third aspect, the structure itself of the diluting unit is not particularly limited, and for example, even if the same diluting unit as the standard gas diluting device used in the conventional standard gas generating device described above is adopted. Good.

A low-concentration standard gas generator according to a fourth aspect of the present invention includes a liquid sample container having a hole containing a liquid sample therein, and a sample gas is introduced into the sample container containing the vapor of the liquid sample. A sample chamber in which gas flows out as a standard gas, a pressure regulator for adjusting the pressure in the sample chamber, a flow rate controller for adjusting the flow rate of the sample gas flowing into the sample chamber, and a standard gas flowing out of the sample chamber A standard gas exhaust path for exhausting a part of the standard gas and a standard gas supply path for supplying the remaining part of the standard gas flowing out from the sample chamber; and the first aspect. And a standard gas diluting device according to 1., wherein the standard gas supply passage of the standard gas generating unit is connected to the main inlet of the standard gas diluting device.

According to the low-concentration standard gas generator according to the fourth aspect, the standard gas generated from the liquid sample is diluted by the standard gas generator to reduce the concentration with high accuracy even if the number of stages of the dilution unit is small. A concentration standard gas can be obtained. In the above-mentioned conventional standard gas generator, the flow rate of the gas flowing through the sample chamber is directly introduced to the diluter because the vapor sample supply flow path is directly connected to the standard gas generator, so that the diluter is used. It was necessary to increase the flow rate of the gas introduced into the chamber to some extent. In this respect, according to the fourth aspect, a part of the standard gas flowing out of the sample chamber is exhausted from the standard gas exhaust passage, and the remaining part of the standard gas flowing out of the sample chamber is separated from the standard gas supply passage. Since air is supplied to the main inlet of the standard gas diluter by means of the above, the amount of gas flowing through the sample chamber is increased to stabilize the evaporation amount of the liquid sample, while the main flow is supplied from the outlet of the first flow rate controller. The flow rate of the gas flowing out to the passage can be reduced.

A low-concentration standard gas generator according to a fifth aspect of the present invention includes a liquid sample container having a hole containing a liquid sample therein, and a sample gas is introduced into the sample container containing vapor of the liquid sample. A sample chamber in which gas flows out as a standard gas, a pressure regulator for adjusting the pressure in the sample chamber, a flow rate controller for adjusting the flow rate of the sample gas flowing into the sample chamber, and a standard gas flowing out of the sample chamber A standard gas exhaust path for exhausting a part of the standard gas and a standard gas supply path for supplying the remaining part of the standard gas flowing out from the sample chamber, and the second or the second standard gas generating section. The standard gas dilution device according to the third aspect, wherein the standard gas supply passage of the standard gas generation unit is one of the plurality of standard gas supply passages of the standard gas dilution device. .

According to the low-concentration standard gas generator according to the fifth aspect, the standard gas generated from the liquid sample and other types of standard gas can be generated by one standard gas diluting device without separately using the standard gas diluting device. Standard gas (for example, cylinder gas) can be diluted, which is economical.

A standard gas generating liquid sample container according to a sixth aspect of the present invention is a container body made of a metal for accommodating a liquid sample and having an opening at an upper portion, and covering the opening of the container main body and the container. A metal cover member having a hole for communicating a space in the main body to the outside, and a metal gasket structure including a part of the container body and a part of the cover member, wherein the container body and the cover member And a gasket structure that keeps the space inside the container body airtight except for the holes.

In the liquid sample container according to the sixth aspect,
Since the container body made of metal, the cover member made of metal, and the gasket structure made of metal including a part of these are used, the manufacturing is easier and less expensive than the one integrally configured by the glass member. Further, since the holes may be formed in the metal cover member, the holes can be formed by, for example, machining using a drill or electrical discharge machining. Therefore, the size and thickness of the holes can be accurately controlled. The desired size and thickness can be well achieved, eliminating the need for time-consuming and labor-intensive calibrations of each manufactured liquid sample container. Further, since the container body and the cover member can be separated, when the liquid sample is taken in and out, the cover member is separated from the container body, and the liquid sample is taken in and out from the opening of the container body. Can be put in and taken out very easily. Since the liquid sample can be taken in and out in this manner, the size of the hole of the cover member is
Since it is possible to reduce the size of the liquid sample so that it cannot be taken in and out from the hole, the vapor amount of the liquid sample can be made extremely small, and the concentration of the standard gas generated can be lowered. Furthermore, since the container body and the cover member can be separated, if a plurality of cover members having different hole sizes are prepared in advance, the evaporation amount of the liquid sample can be changed by simply replacing the cover member. It is possible to change the concentration of the generated standard gas.

A low-concentration standard gas generator according to a seventh aspect of the present invention is the low-concentration standard gas generator according to the fourth or fifth aspect, wherein the liquid sample container generates the standard gas according to the sixth aspect. It is a liquid sample container for use.

In the standard gas generator according to the eighth aspect of the present invention, a flow path is provided with pure gas at one end, a pressure regulator installed in the middle of the flow path, and in the middle of the flow path. A sample chamber installed on the downstream side of the pressure regulator and containing a liquid sample container having a hole containing a liquid sample, and a flow rate controller installed on the downstream side of the sample chamber in the middle of the flow path, Be prepared.

A standard gas generator according to a ninth aspect of the present invention is the standard gas generator according to the eighth aspect, wherein the liquid sample container is the standard gas generating liquid sample container according to the sixth aspect. Is.

In the standard gas generator according to the eighth aspect, the liquid sample container is not limited to the standard gas generating liquid sample container according to the sixth aspect. The liquid sample container used in the low-concentration standard gas generator may be used.
The container with the diffusion tube employed in the device described in K0226 may be used. However, it is preferable to use the liquid sample container according to the sixth aspect as in the ninth aspect because the advantages already described in relation to the sixth aspect can be obtained.

According to the standard gas generators of the eighth and ninth aspects, the pure gas supplied to one end of the flow path is kept at a constant pressure by the pressure regulator and the flow rate is controlled by the flow rate controller. It is kept constant and passes through the sample chamber to become a standard gas toward the other end of the flow path. A cylinder containing pure gas may be connected to one end of the flow path. Therefore, this standard gas generator can be used as an alternative to a cylinder containing standard gas whose concentration has been adjusted in advance with high accuracy. The standard gas generator generates standard gas as needed and does not store standard gas prepared in advance, so that it is easy to handle. Also,
Such a standard gas generator is much more economical than a cylinder containing standard gas whose concentration is adjusted with high accuracy in advance.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION A low-concentration standard gas generator according to an embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a schematic configuration diagram showing a low-concentration standard gas generator according to the present embodiment.

As shown in FIG. 1, one end of a conduit 1 serving as a standard gas supply passage for supplying standard gas from a cylinder (not shown) containing the standard gas is provided at one end of the valve 2. It is connected. The other port of the valve 2 is connected to the inflow port of the first flow rate controller 4 via the conduit 3. One end of a pipeline 5 as a standard gas supply passage for supplying a standard gas of a different type from the standard gas supplied from the pipeline 1 is connected to one port of a valve 6, and the other port of the valve 6 is connected. Is connected to the middle of the pipeline 3 via the pipeline 7. In practice, for example, a collective valve is used as the valves 2 and 6, and the collective valve has a switching unit that switches between the pipeline 1 and the pipeline 5 and connects only one of them to the inlet of the flow rate controller 4. I am configuring.

Further, one end of a pipe line 8 for supplying a high-purity gas (pure gas) from a cylinder, a line gas pipe or the like (not shown) has a flow of a purifier 9 for removing impurities such as molecular sieves. Connected to the entrance. The outlet of the purifier 9 is connected to one end of the heat exchanger 10. The purifier 9 may be removed when the purity of the high-purity gas supplied from the conduit 8 is sufficiently high. The other end of the heat exchanger 10 is connected to the inflow port of the flow rate controller 12 via the pipe 11. The outlet of the flow controller 12 is connected to the inlet of the sample chamber 14 via the pipe 13, and the flow controller 12 adjusts the flow rate of the sample gas flowing into the sample chamber 14. The sample chamber 14 contains a liquid sample container 17 having a hole 16 containing a liquid sample 15. The high-purity gas supplied from the pipe line 8 becomes a sample gas for generating a standard gas, and the sample gas flowing into the sample chamber 14 is the liquid sample 1
It contains 5 vapors and becomes standard gas. The outlet of the sample chamber 14 is connected to the other end of the conduit 5. Also, the sample chamber 1
One end of a pipe 18 as an exhaust passage for exhausting a part of the standard gas flowing out from the pipe 4 is connected to the middle of the pipe 3. When the valve 2 is closed and the valve 6 is opened, the conduit 3 serves as a standard gas supply path for supplying the remaining part of the standard gas flowing out from the sample chamber 14. The other end of the conduit 18 is connected to one port of the needle valve 19. The pressure gauge 20 is connected to the middle of the pipeline 18 via the pipeline 21. When the valve 2 is closed and the valve 6 is open, the pressure in the sample chamber 14 can be adjusted by adjusting the needle valve 19 while observing the pressure gauge 20, and in the present embodiment, the needle valve 19 is used. Reference numeral 19 is a pressure regulator for adjusting the pressure in the sample chamber 14. However, another pressure regulator may be used instead of the needle valve 19. The other port of the needle valve 19 is connected to the intake port of the exhaust pump 23 via the conduit 22. The exhaust port of the exhaust pump 23 is open. In the present embodiment, the elements 5, 7 to 19 described above are used.
Constitutes a standard gas generating part for generating a standard gas by the liquid sample 15.

Further, one end of a pipe line 24 as a main flow path of the standard gas diluting device is connected to the outlet of the first flow rate controller 4. The other end of the pipe line 24 is provided with a high-sensitivity gas analyzer 25 such as an atmospheric pressure mass spectrometer for performing calibration using the low-concentration standard gas finally obtained by the low-concentration standard gas generator according to the present embodiment. It is connected to the inlet. The outlet of the high sensitivity gas analyzer 25 is open. Three branch lines 26, 27 and 28 are branched from the pipe line 24. Flow controllers 29, 30, and 31 are installed in the middle of the branch paths 26, 27, and 28, respectively. An end of the branch path 26, which is opposite to the end of the conduit 24, is connected to one opening of the valve 32, and the other opening of the valve 32 is connected to the middle of the conduit 11 via the conduit 33. It is connected. An end portion of the branch passage 28, which is opposite to the pipe passage 24, is connected to the middle of the branch passage 26. One end of a pipe line 34 for supplying high-purity gas from a cylinder, a line gas pipe or the like (not shown) is connected to an inlet of a purifier 35. The high-purity gas supplied through the conduit 34 is supplied from the conduit 1 when the standard gas supplied through the conduit 1 cannot be diluted with the high-purity gas supplied through the conduit 8. It is used as a diluting gas for diluting the standard gas. The outlet of the purifier 35 is
It is connected to one end of the heat exchanger 36. The other end of the heat exchanger 36 is connected to one port of the valve 37, and the valve 37
The other port of is connected to the middle of the branch path 26. Collective valves are used as the valves 32 and 37. If the standard gas supplied from the conduit 1 can be diluted with the high-purity gas supplied through the conduit 8, the valves 32 and 37, the purifier 35 and the heat exchanger 36 are removed, The conduit 33 and the conduit 26 may be connected in advance. As can be seen from the above description, the first branch path 26 and the third branch path 28 from the side closer to the flow rate controller 4 serve as air supply paths for supplying the pipe 24 with the dilution gas. There is. A heat exchanger 38 is installed between the flow rate controller 30 and the pipeline 24 in the branch passage 27. The end portion of the branch passage 27, which is opposite to the end portion of the pipe passage 24, is connected to the middle of the pipe passage 22. Therefore, the second branch 27 from the flow rate controller 4 is an exhaust path for exhausting gas from the conduit 24.

In this embodiment, the flow rate controller 4,
Pipeline 24, a flow controller 29 installed in the middle 1
A standard gas diluting device by two-stage dilution is configured by the second branch 26, the second branch 27 in which the flow controller 30 is installed in the middle, and the third branch 28 in which the flow controller 31 is installed in the middle. ing. The part on the inlet side of the flow rate controller 4 serves as the main inlet of the standard gas diluting device, and the high-sensitivity gas analyzer 2 of the pipeline 24 is provided.
The end on the 5 side is the main outlet of the standard gas diluting device, and the standard gas diluting device dilutes the standard gas introduced into the main inlet into a low-concentration standard gas and causes it to flow out from the main outlet. . The flow controller 4 and the first branch path 26 in which the flow controller 29 is installed are 1
It constitutes the dilution section of the stage. In addition, a second branch 27 with a flow controller 30 installed midway and a third branch 28 with a flow controller 31 installed midway.
Constitutes the second-stage dilution section.

In the present embodiment, a purifier 41 is installed between the flow rate controller 31 and the pipe 24 in the middle of the branch 28. The purifier 41 is provided to remove coexistence interfering substances and the like generated from the flow rate controller 31. That is, the purifier 41 is
Since the branch path 28 constitutes the final-stage dilution section,
Since the diluting gas is supplied to the portion of the pipe 24 where the sample concentration in the gas is lowered by the branch passage 28, the amount of the coexisting interfering substance generated from the flow rate controller 31 is equal to that of the gas in the portion. It is provided in view of the fact that the amount of sample cannot be ignored. However, if the amount of the coexisting interfering substance generated from the flow rate controller 31 is negligible with respect to the amount of the sample in the gas at the location, the purifier 41 may be removed. Further, if necessary, the flow rate controller 2 may be provided in the middle of the branch path 26.
A purifier may be installed between the pipe 9 and the pipe 24.

The standard gas supplied from the conduit 1 and the high-purity gas supplied from the liquid sample 15 and the conduits 8 and 34 are not particularly limited. Water or alcohol can be used as 15, and nitrogen, argon, hydrogen, oxygen, or the like can be used as the high-purity gas.

Further, in this embodiment, as shown in FIG. 1, in order to prevent the sample component (for example, water) in the gas from being adsorbed on the inner wall of the pipe line 24, the pipe line 24 is heated to a desired high temperature. A temperature controller 39 for heating is provided. In addition to the sample chamber 14, the above-mentioned elements 2 to 7 and 10
-18, 24, 26-33, 36-39 are housed in a constant temperature bath 40 as a temperature controller for adjusting the temperature to a desired constant temperature. The temperature in the sample chamber 14 is kept constant by the constant temperature bath 40, and the sample chamber 1 is controlled by the flow rate controller 12.
Since the flow rate of the gas flowing in 4 is kept constant, the pressure in the sample chamber 14 is kept constant by the needle valve 19, and the size and thickness (depth) of the hole 16 of the liquid sample container 17 are constant. The concentration of the standard gas flowing out from the conduit 5 becomes constant. In addition, in the present embodiment, the above-mentioned elements 2 to
7, 10-18, 24, 26-33, 36-39 are housed in a constant temperature bath 40 and heat exchangers 10, 3
6 and 38 are provided, the flow rate controller 4,
The temperature of the gas is substantially the same on both sides of 12, 29, 30, 31. Therefore, the flow rate controllers 4, 12, 29,
When a high-precision flow rate controller (for example, a flow rate controller of "SEC series" manufactured by STEC Co., Ltd.) having a flow rate sensor that detects a flow rate by detecting a temperature change proportional to the mass flow rate is used as 30, 31 However, the gas flow rate of each part can be controlled with high accuracy, which is preferable. It should be noted that a heat exchanger may be provided between the flow rate controllers 29, 31 and the conduit 24, if necessary.

As the liquid sample container 17, the liquid sample container used in the low-concentration standard gas generator disclosed in the above-mentioned Japanese Patent Laid-Open No. 4-81650 may be used, and it is described in JIS-K0226. The container with the diffusion tube employed in the existing device may be used. However, as the liquid sample container 17, for example, as shown in FIG.
Liquid sample containers 17A, 17 as shown in (a) to (c)
It is preferable to use B and 17C. FIG.
(C) is a cross-sectional view showing an example of the liquid sample container 17.

The liquid sample container 17A shown in FIG.
A cylindrical container main body 50 that holds the liquid sample 15 and has an opening at the top, a disk-shaped gasket 51 having a hole 51a formed in the center, and the gasket 51 are sandwiched between the upper part of the container main body 50. And a tightening member 52. A plurality of holes 51a may be formed if necessary. The tightening member 52 is formed in a cap shape having a large opening 52a in the center, an internal thread portion 52b is formed on the inner peripheral surface of the side portion of the tightening member 52, and the outer surface of the side portion is hexagonal like a nut. Has been done. A male screw portion 50a that is screwed with the female screw portion 52b is formed on the upper portion of the outer peripheral surface of the container body 50. An annular convex portion 50b is formed on an upper surface of the container body 50, and an annular convex portion 5 is formed on a lower surface of an upper portion of the fastening member 52 at a position corresponding to the convex portion 50b.
2c is formed, and the gasket 51 is sandwiched between these convex portions 50b and 52c. Therefore, in the liquid sample container 17A, the gasket 51 is
The container body 50 covers the opening of the container body 50.
The cover member has a hole 51a for connecting the inner space to the outside. Further, in the liquid sample container 17A, the convex portions 50b and 52c and the gasket 51 detachably fix the container body 50 and the gasket 51 that is the cover member, and the space inside the container body 50 is airtight except for the hole 51a. A gasket structure that keeps Container body 50,
The tightening member 52 and the gasket 51 are made of metal such as stainless steel, nickel, and stainless steel plated with gold or silver. In this example, the hole 51a corresponds to the hole 16 of the liquid sample container 17 in FIG.

The liquid sample container 17B shown in FIG.
Since the liquid sample container 17A has almost the same configuration, the same or corresponding elements in FIG. 2 (b) as those in FIG. 2 (a) are designated by the same reference numerals, and the duplicate description thereof will be omitted. The liquid sample container 17B is different from the liquid sample container 17A in that in the liquid sample container 17B, the gasket 51 has an annular shape having a large opening 51b instead of the hole 51a, and the fastening tool 52 has an opening 52a. It only has a hole 52d at the center. Liquid sample container 17B
Then, the tightening member 52 is a cover member having a hole 52d that covers the opening of the container body 50 and connects the space in the container body 50 to the outside. Further, in the liquid sample container 17A, the convex portions 50b and 52c and the gasket 51 detachably fix the container body 50 and the tightening member 52 which is the cover member, and the space inside the container body 50 is removed except for the hole 51a. The gasket structure is kept airtight. In this example, the hole 52d corresponds to the hole 16 of the liquid sample container 17 in FIG.

The liquid sample container 17C shown in FIG.
Since the liquid sample container 17B has almost the same structure, the same or corresponding elements in FIG. 2 (c) as those in FIG. 2 (b) are denoted by the same reference numerals, and the duplicate description thereof will be omitted. The liquid sample container 17C is different from the liquid sample container 17B only in that the liquid sample container 17C does not have an annular convex portion 50b formed on the upper surface of the container body 50.
In the liquid sample container 17B, similarly to the liquid sample container 17C, the tightening member 52 is a cover member that covers the opening of the container body 50 and has a hole 52d that connects the space in the container body 50 to the outside. . Further, in the liquid sample container 17A, the upper surface of the liquid sample container 50, the convex portion 5
The 2c and the gasket 51 constitute a gasket structure that keeps the space inside the container body 50 airtight except the hole 51a by fixing the container body 50 and the fastening member 52, which is a cover member, in a separable manner.

Liquid sample containers 17A, 17B, 17C
According to this, since it is configured as described above, it is easier and cheaper to manufacture as compared with the one integrally configured by the glass member. In addition, a metal gasket 5 that is a cover member
Since it is sufficient to form the holes 51a or 52d in the fastening member 52 or 1a, the holes 51a and 52d can be formed by, for example, machining using a drill or electrical discharge machining, and therefore the holes 51a and 52d. Since the size and thickness of the liquid sample container can be accurately set to the desired size and thickness, it is not necessary to perform time-consuming and labor-intensive calibration for each manufactured liquid sample container 17A (or 17B or 17C). In addition, the container body 50 and the gasket 5
Since the 1 and the tightening member 52 can be separated,
When the liquid sample 15 is taken in and out, the liquid sample 15 can be taken out and put in very easily by separating them and putting the liquid sample 15 in and out through the opening above the container body 50. Since the liquid sample 15 can be taken in and out in this manner, the size of the holes 51a, 52d can be made small so that the liquid sample 15 cannot be taken in and out through the holes 51a, 52d.
The vapor amount of 5 can be made extremely small, and the concentration of the generated standard gas can be lowered. Further, since the container body 50, the gasket 51 and the tightening member 52 can be separated from each other, if a plurality of gaskets 51 or tightening members 52 having different sizes of the holes 51a and 52d are prepared in advance, the gasket which is the cover member. The evaporation amount of the liquid sample 15 can be changed by changing only the 51 or the fastening member 52, and thus the concentration of the standard gas generated can be changed. For the above reasons, it is preferable to use the liquid sample containers 17A, 17B, and 17C as shown in FIGS. 2A to 2C as the liquid sample container 17.

Next, the operation of the low-concentration standard gas generator shown in FIG. 1 will be described.

To obtain the low-concentration standard gas by the liquid sample 15, the valves 2 and 37 are closed and the valves 6 and 32 are opened. As a result, the high-purity gas supplied from the pipe 8 passes through the purifier 9, and then passes through the heat exchanger 10, the pipe 11 and the flow rate controller 12, and the vapor of the liquid sample 15 in the sample chamber 14 has a constant concentration. It becomes the standard gas contained in C, and the standard gas passes through the pipe line 5, the valve 6 and the pipe line 7. Part of the standard gas that has passed through the conduit 7 is exhausted through the conduit 18, the needle valve 19, the conduit 22 and the exhaust pump 23, and the remaining part of the standard gas that has passed through the conduit 7 passes through the conduit 3. After that, it flows into the inlet of the flow rate controller 4. Further, the high-purity gas supplied from the pipeline 8 passes through the purifier 9 and then the pipelines 11, 33
And, via the valve 32, the gas is supplied to the pipe line 24 from the branch lines 26 and 28 as dilution gas, respectively.

Then, the standard gas containing the sample 15 having a constant concentration C flowing into the inlet of the flow controller 4 is diluted by the standard gas diluting device as follows. That is, first, the flow path controller 4 enters the inflow port, flows out of the flow rate controller 4 through the outflow port, and then the pipeline 2
The flow rate of the standard gas having the concentration C flowing into 4 is controlled by the flow rate controller 4 to become the flow rate L1, and then 1
It is diluted with the diluting gas supplied to the pipe line 24 from the second branch line 29 at the flow rate L2 (one-stage dilution). This flow rate control is performed by the flow rate controller 29. Next, a part (flow rate L3) of this first-stage dilution gas is exhausted from the second branch passage 27, and is diluted with the dilution gas supplied to the pipe line 24 from the third branch passage 28 at the flow rate L4. (Two-stage dilution), it becomes an extremely low-concentration standard gas and is supplied to the high-sensitivity gas analyzer 25. This flow rate control is performed by the flow rate controllers 30 and 31.

The sample concentration in the ultra-low concentration standard gas which is finally obtained by diluting as described above is C. [L1 /
(L1 + L2)] [[L1 + L2-L3) / (L1 +
L2-L3 + L4)]. Flow rate L1, L2
By changing L3 and L4 by the flow rate controllers 4, 29, 30 and 31, finally, an extremely low concentration standard gas can be obtained.

On the other hand, when the low-concentration standard gas is obtained based on the standard gas supplied through the conduit 1, the valve 2 is opened and the valves 6 and 19 are closed (the needle valve 19 does not necessarily have to be closed). , One of the valves 32 and 37 is opened and the other is closed. As a result, the standard gas containing the sample at a constant concentration, which is supplied from the pipe line 1, flows into the inlet of the flow rate controller 4 via the valve 2 and the pipe line 3.
Further, the high-purity gas supplied from the pipe 8 or the pipe 34 is used as a diluting gas from the branch pipes 26, 28 to the pipe 24.
Is supplied with air. In this case as well, the standard gas flowing into the inflow port of the flow rate controller 4 is diluted by the standard gas diluting device into an extremely low-concentration standard gas in the high-sensitivity gas analyzer 25 as in the case described above. Supplied.

As can be seen from the above description, according to the present embodiment, the dilution ratio of the first-stage dilution section (the flow controller 4 and the first branch path 26 in which the flow controller 29 is installed in the middle) is , L1 / (L1 + L2), the gas flow rate L1 by the flow rate controller 4 can be accurately reduced, and thus the dilution rate of the first-stage dilution section can be accurately reduced.
Even if the number of stages of the diluting section is small, a highly accurate dilution ratio can be obtained as a whole, and a low-concentration standard gas can be obtained with a high-accuracy concentration. For example, an extremely low-concentration standard gas in the ppt region can also be obtained. It will be possible. According to the present embodiment,
Not all the standard gas flowing out from the sample chamber 14 flows into the flow rate controller 4 as it is, but a part of the standard gas is exhausted from the pipe line 18, and the remaining part of the standard gas is supplied to the flow rate controller 4. Sample chamber 14
The amount of gas flowing through the liquid sample 15 can be increased to stabilize the evaporation amount of the liquid sample 15, and the flow rate L1 of the gas flowing out from the outlet of the flow rate controller 4 to the conduit 24 can be reduced. Even with respect to, it is possible to obtain a highly accurate dilution rate.

By the way, even if background or coexisting substances are generated on the side near the main inlet of the standard gas diluter, the concentration of the standard gas is high on the side near the main inlet, and the amount of sample in the gas is large. The amount of background and coexisting substances is negligible with respect to the amount of sample,
The background and the coexistence interfering substance do not substantially affect the accuracy of the finally obtained low-concentration standard gas concentration.
Therefore, although the flow rate controller 4 is a source of the background and coexistence interfering substances, the flow rate controller 4 is provided on the side closest to the main inlet, and is a main flow path between the outlet of the flow controller 4 and the main outlet. Pipeline 24
Since there is no flow controller or the like that is a source of background and coexistence interfering substances, the low-concentration standard gas can be obtained with high accuracy.

Further, according to the present embodiment, by switching the valve 2 and the valve 6 as described above, different standard gases of different types can be diluted by one standard gas dilution device, which is economical. is there.

Next, a standard gas generator as an alternative means of the standard gas-containing cylinder according to another embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic configuration diagram showing a standard gas generator according to the present embodiment.
In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals.

The standard gas generator according to this embodiment is
The flow path 60 having a pure gas supplied to one end, the pressure adjuster 61 installed in the middle of the flow path 60, the downstream side of the pressure adjuster 61 in the middle of the flow path 60, The sample chamber 14 that encloses the liquid sample container 17 having the hole 16 therein is provided, and the flow rate controller 62 that is installed on the downstream side of the sample chamber 14 in the middle of the flow path 60.
A cylinder containing pure gas, a line gas pipe, or the like may be connected to one end of the flow path 60.

The sample chamber 14 and the liquid sample container 17 in FIG.
Is the same as the sample chamber 14 and the liquid sample container 17 in FIG.
The liquid sample container used in the low-concentration standard gas generator disclosed in Japanese Patent No. 81650 may be used.
The container with the diffusion tube employed in the apparatus described in S-K0226 may be used, but as the liquid sample container 17, for example, a liquid sample container 17A as shown in FIGS. , 17B, 17C are preferably used.

Further, in the present embodiment, a heat exchanger 63 is installed between the sample chamber 14 and the pressure adjuster 61 in the middle of the flow path 60. Sample chamber 14 and heat exchanger 6
3 is housed in a constant temperature bath 64 as a temperature controller that adjusts the temperature to a desired constant temperature. If necessary,
A purifier may be installed on the downstream side of the pressure regulator 61.

According to the present embodiment, the temperature in the sample chamber 14 is kept constant by the constant temperature bath 64, the flow rate of the gas flowing in the sample chamber 14 is kept constant by the flow rate controller 12, and the needle valve 19 is used. Since the pressure in the sample chamber 14 is kept constant and the size and thickness (depth) of the hole 16 of the liquid sample container 17 are constant, the sample 16 passes through the sample chamber 14 and is obtained from the other end of the flow channel 60. The concentration of the standard gas used is constant.

Therefore, the standard gas generator according to the present embodiment can be used as an alternative to a cylinder containing standard gas whose concentration has been adjusted in advance with high accuracy. The standard gas generator generates standard gas as needed and does not store standard gas prepared in advance, so that it is easy to handle.
Further, such a standard gas generator is much more economical than a cylinder containing standard gas whose concentration is adjusted in advance with high accuracy.

When the temperature of the pure gas supplied from one end of the flow passage 60 is different from the desired temperature in the sample chamber 14, the heat exchanger 63 brings the pure gas close to the temperature to raise the temperature. This is preferable for obtaining a standard gas having an accurate concentration, but it is not always necessary in the present invention.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

For example, in the low-concentration standard gas generator shown in FIG. 1, the two standard gas supply passages, that is, the pipelines 1 and 7 are switched, but three or more standard gas supply passages are switched. You may comprise. In addition, the low-concentration standard gas generator shown in FIG.
One or more dilution sections corresponding to the second-stage dilution section may be added to form a three-stage dilution section, or if the dilution rate is not so high, the second-stage dilution section may be removed. It may be composed of a diluting unit in stages.

[0065]

As described above, according to the present invention,
A standard gas diluting device and a low concentration using the standard gas diluting device, which can obtain a low-concentration standard gas with a highly accurate concentration even when the number of stages of the diluting section is small, and can obtain an extremely low-concentration standard gas in the ppt region. A standard gas generator can be provided. Further, according to the present invention, it is possible to provide a standard gas diluting device capable of diluting different kinds of standard gas with one standard gas diluting device and a low-concentration standard gas generating device using the standard gas diluting device. Furthermore, according to the present invention, it is easy and inexpensive to manufacture, and it is not necessary to calibrate all individual items, and furthermore, it is possible to easily take in and out a liquid sample and generate a low-concentration standard gas. It is possible to provide a standard gas generating liquid sample container and a standard gas generating device using the same. Furthermore, according to the present invention, it is possible to provide a standard gas generator as an alternative means that is an inexpensive and easy-to-use alternative to the standard gas-containing cylinder.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a low-concentration standard gas generator according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing each example of a liquid sample container.

FIG. 3 is a schematic configuration diagram showing a standard gas generator according to another embodiment of the present invention.

[Explanation of symbols]

1,3,5,7,8,11,13,18,21,22
33,34 Pipe line 2,6,32,37 Valve 4,12,29-31,62 Flow controller 9,35,41 Purifier 10,36,38,63 Heat exchanger 14 Sample chamber 15 Liquid sample 16 Hole 17 , 17A, 17B, 17C Liquid sample container 19 Needle valve 20 Pressure gauge 23 Exhaust pump 24 Main flow path (pipe line) 26, 27, 28 Branch path 39 Temperature controller 40, 64 Constant temperature chamber 50 Container body 51 Gasket 52 Tightening member 60 Flow path 61 Pressure regulator

Claims (9)

[Claims] 1. A standard gas diluter having a main inlet and a main outlet, wherein a standard gas introduced into the main inlet is diluted into a low-concentration standard gas and flows out from the main outlet, the inlet being the main flow. A first flow controller connected to the inlet; a main flow path having one end connected to the outlet of the first flow controller and the other end connected to the main flow outlet; and 1 branched from the main flow path One or more branch passages, among the one or more branch passages, the odd-numbered branch passages closer to the first flow rate controller supply the dilution gas to the main passage. An air supply passage, in which a flow rate controller is installed on the way, wherein an even-numbered branch passage from the one closer to the first flow controller among the one or more branch passages is Exhaust gas from the main flow path A standard gas diluter characterized in that it is an exhaust path with a flow rate controller installed in the middle. 2. A plurality of standard gas supply passages for supplying different standard gases, and a plurality of the standard gas supply passages are switched to select one of them.
The standard gas diluting device according to claim 1, further comprising: switching means for communicating only one with the main inlet of the standard gas diluting device. 3. A standard gas diluting device having a main inlet and a main outlet, wherein a standard gas introduced into the main inlet is diluted into a low-concentration standard gas and then flows out from the main outlet, different standard gases are used. One of a plurality of standard gas supply passages for supplying air and a plurality of the standard gas supply passages switched between
And a switching means for communicating only one of them with the main inlet of the standard gas diluting device. 4. A sample chamber containing a liquid sample container having a hole containing a liquid sample therein, into which a sample gas flows, and a sample gas containing vapor of the liquid sample flows out as a standard gas, and the sample chamber. Pressure regulator to adjust the pressure of
A flow rate controller for adjusting the flow rate of the sample gas flowing into the sample chamber, a standard gas exhaust path for exhausting a part of the standard gas flowing out of the sample chamber, and a remaining one of the standard gas flowing out of the sample chamber. A standard gas supply section for supplying air to the unit; and a standard gas diluting device according to claim 1, wherein the standard gas supply path of the standard gas generation section is the standard gas supply section. A low-concentration standard gas generator, which is connected to the main inlet of the gas diluter. 5. A sample chamber containing a liquid sample container having a hole containing a liquid sample therein, into which a sample gas is introduced and a sample gas containing vapor of the liquid sample flows out as a standard gas, and the sample chamber. Pressure regulator to adjust the pressure of
A flow rate controller for adjusting the flow rate of the sample gas flowing into the sample chamber, a standard gas exhaust path for exhausting a part of the standard gas flowing out of the sample chamber, and a remaining one of the standard gas flowing out of the sample chamber. A standard gas supply section for supplying air to the unit, and a standard gas diluting device according to claim 2 or 3, wherein the standard gas supply path of the standard gas generation section is A low-concentration standard gas generator, which is one of the plurality of standard gas supply paths of the standard gas diluter. 6. A metal container main body for accommodating a liquid sample and having an opening above, and a metal container main body having a hole for covering the opening of the container main body and for communicating a space in the container main body to the outside. A cover member, and a metal gasket structure including a part of the container body and a part of the cover member, wherein the container body and the cover member are detachably fixed to form a space in the container body. A standard gas generating liquid sample container, comprising: a gasket structure for keeping airtight except for the holes. 7. The low-concentration standard gas generator according to claim 4 or 5, wherein the liquid sample container is the standard gas generating liquid sample container according to claim 6. 8. A flow path to which pure gas is supplied at one end, a pressure adjuster installed in the middle of the flow path, and a flow adjuster installed downstream of the pressure adjuster in the middle of the flow path. A standard gas generator, comprising: a sample chamber containing a liquid sample container having a hole containing a sample therein; and a flow rate controller installed on the downstream side of the sample chamber in the middle of the flow path. 9. The standard gas generator according to claim 8, wherein the liquid sample container is the standard gas generating liquid sample container according to claim 6.