JP6079681B2 - Gas sampler - Google Patents

Description

  The present invention relates to a gas sampler that supplies sample gas to be analyzed to various gas analyzers.

  In many gas analyzers such as a gas chromatograph, a sample gas to be analyzed is introduced by a fixed amount through a gas sampler. In general, the sample gas supplied to the gas analyzer is metered so that the amount of the sample gas is constant. After the sample gas is once introduced into the sample loop having a constant capacity, the carrier gas is introduced into the sample loop, and then the sample gas is sampled. A method of feeding a sample gas that fills the inside of the loop to a gas analyzer is employed (see, for example, Patent Document 1).

  In such a gas sampler, the sample gas introduction pipe leading to the sample gas source and the carrier gas introduction pipe leading to the carrier gas source are selectively switched so as to communicate with the sample loop, or the sample loop and the gas are connected. Since it is necessary to switch a plurality of pipes, for example, by appropriately communicating with the analyzer, a multi-port valve such as a six-way valve is frequently used for switching these pipes (for example, Patent Document 1 and Patent Document 2).

  Various types of multi-port valves are known, but in order to change the communication state between each port, any type of multi-port valve has a valve body or the like inside the casing of the valve. Although it has a drive unit that switches the flow path inside the valve by moving the moving member, if ambient air enters the drive unit and mixes with sample gas, it may lead to erroneous analysis results Become. In order to prevent this, conventionally, the periphery of the drive unit in the casing is generally purged with a gas that does not affect the analysis result.

  FIG. 2 is a schematic diagram conceptually showing the structure of a conventional gas sampler in which the above measures are taken. In this example, the multi-port valve 21 is a six-way valve, and its ports 21a to 21f communicate with a sample gas introduction pipe 22 that communicates with the sample gas source, each end on both sides of the sample loop 23, and a carrier gas source. The carrier gas introduction pipe 24, the sample gas supply pipe 25 communicating with the gas analyzer, and the exhaust pipe 26 communicating with the outside are connected to each other.

The operation of supplying a certain amount of sample gas to the gas analyzer with the above-described pipe configuration will be briefly described.
First, the flow path in the multi-port valve 21 is in a state where the portions indicated by solid lines in the drawing are in communication. As a result, the sample gas flows into the sample loop 23 from the sample gas introduction pipe 22 through the ports 21a and 21b, and is discharged to the outside through the exhaust pipe 26 through the ports 21e and 21f. Then, after the inside of the sample loop 23 is filled with the sample gas, the multi-port valve 21 is switched so that the portion indicated by the broken line in FIG. As a result, the carrier gas from the carrier gas introduction pipe 24 flows into the sample loop 23 through the ports 21c and 21b, and the sample gas filling the inside of the sample gas is supplied from the sample gas supply pipe 25 through the ports 21e and 21d. Sent to the gas analyzer.

  In order to prevent air from entering the driving portion of the multiport valve 21 operating in this way, a purge gas inlet Ipg and a purge gas outlet Opg are formed in the casing C of the multiport valve 21, and the purge gas from the purge gas source is formed. Is supplied from the purge gas introduction port Ipg through the purge gas introduction pipe 27 toward the drive unit in the casing C, and is discharged from the purge gas outlet port Opg through the purge gas discharge pipe 28 to the outside. As a result, the periphery of the driving portion of the multiport valve 21 is always covered with the gas, thereby preventing the surrounding air from entering. As the purge gas, a gas that does not affect the analysis, for example, the same gas as the carrier gas or the main component gas of the sample is used.

Japanese Patent Laid-Open No. 2-91564 JP2013-205324A

  By the way, in the gas sampler as described above, in which the sample gas is sealed in the sample loop to measure a certain amount and supplied to the gas analyzer, the sample gas is replaced when the amount of sample gas to be replaced in the sample loop is not sufficient. Analysis results may be affected by air remaining in the loop being sent to the analyzer.

  The present invention solves such a problem and can obtain a good analysis result even with a small amount of sample gas that is insufficient to replace the inside of the sample loop. In addition, the issue is to provide a gas sampler that can suppress an increase in running cost.

  In order to solve the above problems, a gas sampler of the present invention is a device for supplying a sample gas to be analyzed to a gas analyzer, and includes a multiport valve, and the multiport valve includes at least a sample. A port to which a sample gas introduction pipe for introducing a sample gas from a gas source is connected, a port to which both ends of a sample loop for measuring the sample gas are respectively connected, a carrier gas introduction pipe for introducing a carrier gas, and gas analysis A port to which a sample gas supply pipe for supplying a sample gas toward the apparatus is connected, and after introducing the sample gas from the sample gas introduction pipe into the sample loop, the carrier gas from the carrier gas introduction pipe is introduced into the sample loop. The sample gas in the sample loop is introduced through the sample gas supply pipe. In the gas sampler configured to be supplied to the gas analyzer, the casing of the multi-port valve is switched to the drive unit for changing the communication state between the ports by switching the internal flow path of the valve. A purge gas inlet for introducing the purge gas and a purge gas outlet for discharging the purge gas are provided, and the purge gas discharged from the purge gas outlet is selectively introduced into the sample loop through the sample gas inlet pipe. It is characterized by having a piping system to be introduced.

  Here, in the present invention, as a specific configuration of the piping system that selectively introduces the purge gas into the sample loop via the sample gas introduction pipe, a three-way valve provided in the middle of the sample gas introduction pipe And a pipe connecting one port of the three-way valve and the purge gas discharge port.

  The present invention seeks to solve the problem by using a purge gas introduced for the purpose of preventing intrusion of ambient air toward the drive portion of the multi-port valve in order to eliminate the gas remaining in the sample loop. .

  In other words, the purge gas that has been introduced into the casing of the multi-port valve through the purge gas inlet and exhausted from the purge gas outlet through the periphery of the valve drive section is introduced into the sample loop through the multi-port valve in the present invention. The configuration is such that the gas is selectively introduced through the sample gas introduction pipe. This allows the purge gas to always flow in the sample loop except when the sample gas is introduced, and no problematic gas such as air that adversely affects the analysis result remains in the sample loop. Even if the amount is insufficient to displace in the sample loop, the analysis results are not affected.

  Also, the purge gas that replaces the inside of the sample loop before the introduction of the sample gas uses the purge gas supplied and discharged around the multiport valve drive unit as it is, so it is dedicated for purging the inside of the sample loop. No purge gas is required.

According to the present invention, since the inside of the sample loop before introducing the sample gas can be replaced with the purge gas, even if the amount of the sample gas is small, there is no residue of air or the like, and a good analysis result can be obtained.
In addition, the purge gas that replaces the inside of the sample loop introduces the purge gas that has been purged around the drive section of the multi-port valve, so it can be improved by the addition of a simple piping system. It is not necessary to separately increase the purge gas used for the purpose, and an increase in running cost can be suppressed.

The schematic diagram which shows notionally the principal part structure of embodiment of this invention. The schematic diagram which shows notionally the principal part structure of the conventional gas sampler.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram conceptually showing a main part configuration in an embodiment of the present invention, and shows an example in which the same six-way valve as FIG. 2 is used as a multiport valve.

  Similarly to FIG. 2, the six ports 1a to 1f of the multi-port valve 1 communicate with the sample gas introduction pipe 2 that communicates with the sample gas source, the ends on both sides of the sample loop 3, and the carrier gas source, respectively. A carrier gas introduction pipe 4, a sample gas supply pipe 5 for supplying sample gas to the gas analyzer, and an exhaust pipe 6 communicating with the outside are connected.

  The casing C of the multi-port valve 1 has a purge gas inlet Ipg for introducing purge gas from a purge gas source toward a drive unit that moves the moving body when the internal flow path is switched, and for discharging the purge gas. The purge gas discharge port Opg is provided, and the purge gas introduction tube 7 and the purge gas discharge tube 8 are connected to the purge gas introduction port Ipg and the discharge port Opg, respectively, as in the example of FIG.

  The feature of this embodiment is that a three-way valve 9 is provided on the pipe line of the sample gas introduction pipe 2, and a purge gas discharge pipe 8 is connected to one port of the three-way valve 9. By driving the three-way valve 9, the state in which the sample gas from the sample gas source is guided to the port 1 a of the multiport valve 1 through the sample gas introduction pipe 2 and the purge gas discharged from the purge gas discharge port Opg as in the prior art, A state of being led to the port 1a of the multiport valve 1 through the purge gas discharge pipe 8 and the three-way valve 9 and the sample gas introduction pipe 2 can be selected.

  The three-way valve 9 is set so as to guide the purge gas that has passed through the purge gas discharge pipe 8 from the purge gas discharge port Opg to the port 1a of the multiport valve 1 except during sampling of the sample gas. Further, in this state, the multi-port valve 1 is set in a state in which the portion indicated by the solid line in FIG. As a result, the purge gas from the purge gas source flows into the drive part in the casing C of the multiport valve 1 through the purge gas introduction pipe 7 and is discharged out of the casing C through the purge gas discharge pipe 8. The sample gas is introduced into the sample loop 3 through the sample gas introduction pipe 2 and the ports 1a and 1b via the three-way valve 9, and flows out from the exhaust pipe 6 through the ports 1e and 1f. Therefore, the inside of the sample loop 3 is always replaced with the purge gas.

  In this state, when a certain amount of sample gas is metered and supplied to the gas analyzer, the state of the multi-port valve 1 remains unchanged, and the three-way valve 9 is switched so that the sample gas from the sample gas source is fed into the sample loop 3. The carrier gas from the carrier gas source is caused to flow through the gas analyzer during this time. Thereafter, the flow path in the multi-port valve 1 is brought into a state in which the portion indicated by the broken line in FIG. 1 is communicated, so that the carrier gas from the carrier gas source is guided into the sample loop 3 and fills the interior thereof. A certain amount of sample gas is fed into the gas analyzer.

  After the above operation, the multi-port valve 1 and the three-way valve 9 are switched to return the purge gas to flow through the sample loop 3.

  According to the above-described embodiment of the present invention, when the sample gas is weighed in a certain amount and sent to the gas analyzer, the inside of the sample loop 3 is always replaced with the purge gas. Even if the sample gas is small, gas such as air that affects the analysis is not supplied to the gas analyzer, and a good analysis result is always obtained.

  In addition, since the purge around the driving portion of the multiport valve 1 and the purge in the sample loop 3 are performed by the same purge gas flow, the gas for purging in the sample loop 3 becomes substantially unnecessary, and the sample loop The purge gas consumption can be reduced as compared with the case where a separate purge gas is supplied for purging the inside of the cylinder 3.

  In the above embodiment, an example using a six-way valve as the multiport valve 1 has been shown. However, the present invention is not limited to this, and even a gas sampler using another multiport valve, such as an eight-way valve, Of course, the present invention can be equally applied to a gas sampler having a sample loop.

DESCRIPTION OF SYMBOLS 1 Multiport valve 1a-1f Port 2 Sample gas introduction pipe 3 Sample loop 4 Carrier gas introduction pipe 5 Sample gas supply pipe 6 Exhaust pipe 7 Purge gas introduction pipe 8 Purge gas discharge pipe 9 Three-way valve C Casing Ipg Purge gas introduction port Opg Purge gas discharge port

Claims (2)

A device for supplying a sample gas to be analyzed to a gas analyzer, comprising a multi-port valve, to which at least a sample gas introduction pipe for introducing a sample gas from a sample gas source is connected Port connected to both ends of the sample loop for measuring the sample gas, a carrier gas introduction pipe for introducing the carrier gas, and a sample gas supply pipe for supplying the sample gas toward the gas analyzer After the sample gas is introduced from the sample gas introduction pipe into the sample loop, the carrier gas from the carrier gas introduction pipe is introduced into the sample loop, and the sample gas in the sample loop is introduced into the sample loop. Gas sun configured to supply gas analyzer via gas supply line In La,
A purge gas introduction port for introducing purge gas toward the drive unit for switching the internal flow path of the valve to change the communication state between the ports and discharging the purge gas to the casing of the multi-port valve A purge gas outlet is provided,
A gas sampler comprising a piping system for selectively introducing the purge gas discharged from the purge gas discharge port into the sample loop through the sample gas introduction pipe.   A piping system for selectively introducing the purge gas into the sample loop through the sample gas introduction pipe includes a three-way valve provided in the middle of the sample gas introduction pipe, one port of the three-way valve, and the above The gas sampler according to claim 1, wherein the gas sampler is constituted by a pipe connecting the purge gas discharge port.

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