JPH085619A - Gas chromatograph - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a gas chromatograph with reduced running costs. [Composition] A first conduit through which the selected one sample flows
(10a, 10b, 10c ...), a second pipeline (12) branching from the first pipeline toward the separation column (30), and a standard gas provided near the end of the first pipeline. A supply valve (6), a third pipeline (14) upstream from a branch point of the second pipeline and branched from the first pipeline via a needle valve, and a downstream side of the third pipeline In the measurement mode, the exhaust gas valve is opened to open the exhaust gas valve so that the selected sample is directed toward the separation column through the first and second conduits, and the calibration is performed. In the mode, first, the exhaust gas valve is opened and the standard gas is delivered at a relatively large flow rate for a predetermined time, and after a predetermined time has elapsed, the exhaust gas valve is closed and the standard gas is delivered at a relatively small flow rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a sampling section of a gas chromatograph, and more particularly to a gas chromatograph designed to reduce the consumption of standard gas in a calibration mode.

[0002]

2. Description of the Related Art In a gas chromatograph, a sample of a process is sampled by a sampling valve, the sample is moved in a gas state in a separation column in an analysis unit, and the components of the sample are separated by utilizing the difference in the moving speed. It is separated, and an output signal according to its component and content, that is, a so-called chromatogram signal is obtained.

FIG. 2 is a schematic view of the essential parts of a conventional example of such a gas chromatograph. Area A is a pretreatment chamber that adjusts the sample collected from each point of the plant to a gas suitable for analysis, area B is a sampling unit that selects one of the pretreated samples, and area C is a separation column or detector. Is a constant temperature bath section in which is arranged.

The sample processed in the pretreatment chamber A is sent to the sampling section B through a plurality of pipes 1a, 1b .... Two
are pressure reducing valves provided in pipes in the sampling unit B, and 3a, 3b ... Are throttle valves. Reference numerals 4a, 4b ... Are sample valves opened and closed in a predetermined order. 10
a, 10b, 10c ... One end has sample valves 4a, 4b ...
Is the first pipeline (the pipeline shown by the dotted line) connected to
Is a second pipe line (a pipe line indicated by a chain line) that is branched in the middle of the first pipe line 10a (point X) and is connected to the separation column 30 side.

Reference numeral 14 is a third conduit (a conduit indicated by a chain double-dashed line), one end of which is connected to the first conduit 10 via the needle valves 5a, 5b.
are connected to branch points (Ya, Yb ...) On the upstream side of b, 10c. 6 is the first conduit 10a
The standard gas supply valve 15 provided near the end of the is a bypass pipe formed by connecting the first conduit 10a and the third conduit 14 and having a needle valve 5v in the middle.

In the above configuration, when neither in the measurement mode nor in the calibration mode, the sample valves 4a, 4b ... And the standard gas supply valve 6 are closed, and the sample gasified in the pretreatment chamber A is decompressed by the pressure reducing valve 2a. , 2b ... and throttle valves 3a, 3b ...
And is returned to the pretreatment chamber A side. Next, in the measurement mode, for example, if the sample of the pipe 1a is selected, the sample valve 4a is opened and the sample is supplied to the first conduit 10b and Ya.
It branches at a point and flows into the third conduit 14 via the needle valve 5a.

Further, a part of the sample passing through the first conduits 10b → 10a is branched at the point X, flows through the second conduit 12 to the separation column 30 side, is analyzed for components, and is branched. The sample that did not exist is discharged from the end of the third conduit 14 through the bypass pipe 15 having the needle valve 5v. On the other hand, the sample branched to the third conduit 14 at the point Ya is also discharged from the end of the third conduit 14.

Next, when the sample in the pipe 1b is selected, the sample valve 4a is closed and at the same time the sample valve 4b is opened, and the selected sample branches into the first conduit 10c and the third conduit 14. Then, a part of the sample flowing into the first conduit 10c branches at the point X and passes through the second conduit 12 to separate the separation column 3
The sample that has flowed to the 0 side for component analysis is performed, and the unbranched sample passes through the bypass pipe 15 having the needle valve 5v to the third position.
It is discharged from the end of the pipeline 14. On the other hand, the sample branched to the third conduit 14 is also discharged from the end of the conduit.

Next, in the calibration mode, the sample valve 4b is closed and the standard gas supply valve 6 is simultaneously opened. When the standard gas is supplied from the standard gas supply means through the standard gas supply valve 6, the standard gas flows into the first conduit 10a and the third conduit through the needle valve 5v provided in the bypass pipe 15. It is discharged from 14. On the other hand, the standard gas that has flowed to the side of the first pipeline 10a is branched on the way (point X), and the second pipeline 1
The gas that flows through the second side to the separation column 30 side and functions as a standard gas, and the gas that has not branched is flowed to the third conduit 14 via Ya, Yb and the needle valves 5a, 5b, and is discharged from the discharge port. Each of the needle valves 5a, 5b ... 5v acts as a standard gas escape passage during calibration and also functions as a control valve for adjusting the amount of the sample toward the separation column 30.

[0010]

By the way, in the conventional gas chromatograph described above, in the calibration mode, the standard gas is branched to the outlet side of the third pipe via the bypass valve, so that the standard gas consumption increases. There is a problem that standard gas is uneconomical because it is expensive. The present invention has been made to solve the above-mentioned problems of the prior art. By reducing the amount of standard gas flowing through the bypass pipe during calibration, the running cost is reduced and the measurement error due to the residual measurement gas is eliminated. An object of the present invention is to provide a gas chromatograph in which a calibration error caused by a pipe adsorption of an adsorbable component in a standard gas is reduced by causing a relatively large flow rate to flow.

[0011]

In order to solve the above problems, the present invention is a gas chromatograph in which a sample is analyzed by an analysis unit and the obtained result (chromatogram signal) is analyzed by the analysis means and displayed or recorded. In the first pipe (1), the samples collected at a plurality of locations are taken in through a plurality of pipes (1a, 1b ...), and one of the selected samples flows.
0a, 10b, 10c ...) and a separation column branched from the first conduit
A second pipeline (12) directed to (30), a standard gas supply valve (6) provided near the end of the first pipeline, and an upstream side of a branch point of the second pipeline and A third pipe line (14) branched from the first pipe line via a needle valve and an exhaust gas valve (17) provided on the downstream side of the third pipe line, and the exhaust gas valve in the measurement mode. Open to open the selected sample to the first,
The calibration gas is directed to the separation column through the second pipe, and in the calibration mode, the exhaust gas valve is opened to send the standard gas at a relatively large flow rate for a predetermined time, and after the predetermined time has passed, the exhaust gas valve is turned on. It is characterized in that the standard gas is sent out at a relatively small flow rate as a closed state.

[0012]

When the standard gas is flowed at a relatively large flow rate for a predetermined time by opening the exhaust gas valve at the beginning of calibration, the sample gas staying in each pipe is removed. Next, when the exhaust gas valve is closed, a relatively small amount of standard gas flows only toward the separation column side.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of a gas chromatograph according to the present invention. In the figure, the difference from FIG. 2 is that an exhaust gas valve 17 is provided near the outlet of the third conduit 14. That is, in the present invention, an exhaust gas valve 17 such as an electromagnetic valve is attached to the downstream side (near the discharge port) of the connection point (point Z) between the bypass pipe 15 and the third pipeline.

In the above construction, the exhaust gas valve 17 is open in the measurement mode, and the gas chromatograph functions exactly as in the conventional case. In the calibration mode, the sample valves 4a, 4b ... Are closed and the standard gas supply valve 6 is opened to supply the standard gas at a relatively large flow rate for a predetermined time. Due to this, the first pipelines 10a, 10b, 1
0c, the second pipeline 12, the third pipeline 14, and the sample gas accumulated in the bypass pipe 15 are removed.

Next, when the exhaust gas valve 17 is closed after a lapse of a predetermined time, the standard gas does not flow to the discharge port but only flows to the separation column 30 side. Therefore, even if the standard gas is delivered at a relatively low flow rate, the calibration operation will function sufficiently. In addition, according to the result of the experiment by the configuration of the present invention, the standard gas consumption amount could be reduced to about 1/10 of the conventional amount.

[0016]

According to the present invention as described in detail with reference to the embodiments, the samples collected at a plurality of locations are taken in through a plurality of pipes, and the selected one sample flows. A pipeline, a second pipeline branching from the first pipeline to the separation column, a standard gas supply valve provided near the end of the first pipeline, and a branch point of the second pipeline. The exhaust gas valve has a third pipe branching upstream from the first pipe via a needle valve and an exhaust gas valve provided downstream of the third pipe, and the exhaust gas valve is in a measurement mode. Is opened to direct the selected sample toward the separation column through the first and second conduits, and in the calibration mode, the exhaust gas valve is opened to start the standard gas for a predetermined time at a relatively large flow rate. The exhaust gas valve is closed after a predetermined time and the standard Since so as to deliver a scan relatively small flow rate, it is possible to realize a gas chromatograph thereby reducing the running cost.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a gas chromatograph showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a gas chromatograph showing a conventional example.

[Explanation of symbols]

 1a, 1b ... Plural pipes 2a, 2b ... Pressure reducing valve 3a, 3b ... Throttle valve 4a, 4b ... Sample valve 5a, 5b ..., 5v Needle valve 6 Standard gas supply valve 10a, 10b, 10c First pipeline 12 Second Pipe line 14 Third pipe line 15 Bypass pipe 17 Exhaust valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Himeno 2-932 Nakamachi, Musashino City, Tokyo Yokogawa Electric Co., Ltd. (72) Inventor Mikio Kobayashi 2-932 Nakamachi, Musashino City, Tokyo Yokogawa Electric Co., Ltd.

Claims (1)

[Claims] 1. A gas chromatograph in which a sample is analyzed by an analyzing unit and the obtained result (chromatogram signal) is analyzed and displayed or recorded by an analyzing means. , 1b ...), and the selected one of the samples flows through the first conduit.
(10a, 10b, 10c ...), a second pipeline (12) branching from the first pipeline toward the separation column (30), and a standard gas provided near the end of the first pipeline. A supply valve (6), a third pipeline (14) upstream from a branch point of the second pipeline and branched from the first pipeline via a needle valve, and a downstream side of the third pipeline In the measurement mode, the exhaust gas valve is opened to open the exhaust gas valve so that the selected sample is directed toward the separation column through the first and second conduits, and the calibration is performed. In the mode, the exhaust gas valve is first opened to deliver the standard gas at a relatively large flow rate for a predetermined time, and after the predetermined time has passed, the exhaust gas valve is closed to deliver the standard gas at a relatively small flow rate. A gas chromatograph characterized in that