Gas chromatograph

Abstract

The invention provides a gas chromatograph capable of preventing a filling material in a sample vaporizing chamber or a split flow path from shifting from a filling position. In a sample vaporizing chamber (21), a sample gas is generated by vaporizing a liquid sample therein. The shunt flow path (4) discharges the sample gas in the sample vaporizing chamber (21). A diverter valve (41) is provided in the diverter flow path (4), and the diverter valve (41) opens and closes in order to adjust the flow rate of the sample gas flowing in the diverter flow path (4). The filling material (26, 421) is filled at a filling position in the sample vaporizing chamber (21) or at a filling position in the shunt flow path (4). When the sample gas in the sample vaporizing chamber (21) is discharged from the shunt flow path (4), the control unit (7) controls the opening degree of the shunt valve (41) such that the pressure in the sample vaporizing chamber (21) is reduced at a pressure gradient that is smaller than a pressure gradient at which the filling material (26, 421) is shifted from the filling position.

Description

Technical Field

[0001] The present invention relates to a gas chromatograph that discharges a sample gas generated by vaporizing a liquid sample in a sample vaporization chamber from a branch flow path. Background Art

[0002] The gas chromatograph comprises: a sample vaporization chamber for generating sample gas by vaporizing a liquid sample in the sample vaporization chamber; and a branch flow path for discharging the sample gas in the sample vaporization chamber. A valve (a branch flow valve) is provided in the branch flow path, and the valve is opened and closed to adjust the flow rate of the sample gas flowing in the branch flow path.

[0003] In the gas chromatograph disclosed in Patent Document 1, a liner (insert) composed of a glass tube is inserted into a sample vaporization chamber. An adsorbent or the like as a filling material is filled in the liner at a predetermined filling position.

[0004] In the gas chromatograph disclosed in Patent Document 2, a filter is provided in the branch flow path. The filter is provided at a predetermined filling position in the branch flow path, and can collect components in the sample gas using a granular filling material filled in the filter.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-256714

[0008] Patent Document 2: International Publication No. 2017 / 191673 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] When the gas chromatograph is operating, the pressure in the sample vaporization chamber is high. When the gas chromatograph is stopped, the sample gas in the sample vaporization chamber can be discharged from the bypass flow path by opening the bypass valve. At this time, when the bypass valve is fully opened, the pressure in the sample vaporization chamber decreases with a large pressure gradient.

[0011] When the pressure in the sample vaporization chamber decreases with a large pressure gradient, the filling material in the liner of the sample vaporization chamber may shift from the filling position. In this case, the liquid sample injected into the sample vaporization chamber is unevenly affected by the heat from the filling material, so that uniform vaporization does not occur, resulting in the possibility of deterioration of analysis reproducibility.

[0012] In addition, when the pressure in the sample vaporization chamber decreases with a large pressure gradient, the filter in the bypass flow path may be offset from the filling position. In this case, the granular filling material filled in the filter may flow out from the filter through the bypass flow path. If the components in the bypass valve arranged on the downstream side swallow the particles of the filling material flowing out of the filter, the bypass valve may also fail.

[0013] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas chromatograph capable of preventing a packing material in a sample vaporization chamber or a branch flow path from shifting from a filling position.

[0014] Solutions for solving problems

[0015] A gas chromatograph according to one embodiment of the present invention comprises a sample vaporization chamber, a bypass flow path, a valve, a filling material, and a control unit. In the sample vaporization chamber, a sample gas is generated by vaporizing a liquid sample inside. The bypass flow path is used to discharge the sample gas in the sample vaporization chamber. The valve is provided in the bypass flow path, and the valve is opened and closed in order to adjust the flow rate of the sample gas flowing in the bypass flow path. The filling material is filled in a filling position in the sample vaporization chamber or a filling position in the bypass flow path. When the sample gas in the sample vaporization chamber is discharged from the bypass flow path, the control unit controls the opening of the valve in such a way that the pressure in the sample vaporization chamber is reduced by a pressure gradient smaller than the pressure gradient that causes the filling material to deviate from the filling position.

[0016] Effects of the Invention

[0017] According to the aspect of the present invention, it is possible to prevent the filling material in the sample vaporization chamber or the branch flow channel from shifting from the filling position. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram showing a configuration example of a gas chromatograph according to one embodiment of the present invention.

[0019] Figure 2 It is a schematic cross-sectional view showing the specific structure of the sample introduction section.

[0020] Figure 3 is a block diagram showing the electrical structure of a gas chromatograph.

[0021] Figure 4 This is a flowchart showing an example of processing performed by the control unit when controlling the flow dividing valve.

[0022] Figure 5A This is a diagram showing an example of pressure change when the target value of the pressure control in the sample vaporization chamber performed by the control unit is maintained at a constant gradient.

[0023] Figure 5B This is a diagram showing an example of pressure change when the gradient of the target value of the pressure control in the sample vaporization chamber performed by the control unit is switched during the process. DETAILED DESCRIPTION

[0024] 1. The overall structure of the gas chromatograph

[0025] Figure 1 1 is a schematic diagram showing a configuration example of a gas chromatograph 100 according to an embodiment of the present invention. The gas chromatograph 100 is used to perform analysis by supplying a sample gas together with a carrier gas into a column 1, and in addition to the column 1, it also includes a sample introduction section 2, a gas supply flow path 3, a branch flow path 4, a purge flow path 5, a detector 6, and the like.

[0026] The column 1 is composed of, for example, a capillary column, and during analysis, the column 1 is heated in a column oven. One end of the column 1 is connected to a sample introduction portion 2, and a sample gas is introduced into the column 1 from the sample introduction portion 2 through a column inlet 11 together with a carrier gas. The other end of the column 1 is connected to a detector 6. The detector 6 can be composed of various detectors such as a hydrogen flame ionization detector (FID).

[0027] A sample vaporization chamber 21 as a space for vaporizing the sample is defined inside the sample introduction section 2. Specifically, the sample introduction section 2 includes a hollow housing 22 and a diaphragm 23 for sealing the housing 22. An opening (not shown) is formed in the housing 22, and the opening is blocked by the flexible diaphragm 23. The sample gas generated by injecting a liquid sample into the sample vaporization chamber 21 and vaporizing the liquid sample in the sample vaporization chamber 21 is introduced into the column 1 from the column inlet 11 together with the carrier gas. The sample vaporization chamber 21 is connected to the gas supply flow path 3, the branch flow path 4, and the purge flow path 5.

[0028] The gas supply flow path 3 is a flow path for supplying a carrier gas to the sample vaporization chamber 21 of the sample introduction section 2. The gas supply flow path 3 is provided with, for example, a flow sensor 31 and a full flow valve 32. The flow sensor 31 detects the flow rate of the carrier gas in the gas supply flow path 3. The full flow valve 32 can arbitrarily adjust the flow rate of the carrier gas in the gas supply flow path 3 between an open state in which the carrier gas is supplied from the gas supply flow path 3 to the sample introduction section 2 and a closed state in which the supply of the carrier gas is stopped by opening or closing the gas supply flow path 3.

[0029] The split flow path 4 is a flow path for discharging a portion of the gas (mixed gas of the carrier gas and the sample gas) in the sample vaporization chamber 21 to the outside at a predetermined split ratio when the carrier gas and the sample gas are introduced into the column 1 from the column inlet 11 by the split flow introduction method. The split flow path 4 is provided with, for example, a split valve 41 and a split filter 42.

[0030] The bypass valve 41 is opened and closed to adjust the flow rate of the sample gas flowing in the bypass flow path 4. Specifically, the bypass valve 41 can arbitrarily adjust the flow rate of the gas in the bypass flow path 4 between an open state in which the gas is discharged from the sample introduction part 2 through the bypass flow path 4 and a closed state in which the gas is stopped from being discharged from the sample introduction part 2 by opening or closing the bypass flow path 4. The bypass filter 42 is set at a predetermined filling position in the bypass flow path 4, and the components in the sample gas can be collected by the granular filling material 421 filled in the bypass filter 42. Since there is no fixing device for fixing the filling material 421, when an external force is applied to the filling material 421, if the external force is greater than the friction force, the filling material 421 may sometimes be offset from the filling position.

[0031] In this example, the flow dividing filter 42 is disposed at a position closer to the sample introduction portion 2 than the flow dividing valve 41, and can collect components derived from the sample that may deteriorate the flow dividing valve 41. When the packing material 421 deviates from the filling position and flows out of the flow dividing filter 42, the components such as the flow dividing valve 41 disposed on the downstream side may swallow particles of the packing material 421 and cause failure.

[0032] The purge flow path 5 is a flow path for discharging undesired components generated from the diaphragm 23 and the like to the outside. For example, an inlet pressure sensor 51, a purge valve 52, a purge pressure sensor 53, and a flow path resistance member 54 are provided in the purge flow path 5. The inlet pressure sensor 51 is provided at a position on the upstream side (the sample introduction part 2 side) of the purge valve 52, and is used to detect the pressure of the gas in the sample vaporization chamber 21, that is, the pressure of the gas at the column inlet 11 (inlet pressure). The purge valve 52 can arbitrarily adjust the flow rate of the gas in the purge flow path 5 between an open state in which the gas is discharged from the sample introduction part 2 through the purge flow path 5 and a closed state in which the gas is stopped from being discharged from the sample introduction part 2 by opening or closing the purge flow path 5. The purge pressure sensor 53 detects the pressure in the purge flow path 5 at a position on the downstream side of the purge valve 52. The flow path resistance member 54 is provided at a position on the downstream side of the purge pressure sensor 53 to limit the flow rate of the gas in the purge flow path 5 to a certain value.

[0033] The purge flow path 5 has a small gas flow rate and the gas flows at a substantially constant flow rate, so that pressure loss is unlikely to occur. Therefore, the inlet pressure can be detected more accurately by providing an inlet pressure sensor 51 in the purge flow path 5. However, the inlet pressure sensor 51 is not limited to being provided in the purge flow path 5, and may be provided in any other portion (such as the branch flow path 4) that communicates with the column inlet 11.

[0034] The flow sensor 31, the full flow valve 32, the diverter valve 41, the inlet pressure sensor 51, the purge valve 52, the purge pressure sensor 53, and the flow path resistance 54 constitute a flow controller 200. The flow controller 200 is used to control the flow of gas in the gas supply flow path 3, the diverter flow path 4, and the purge flow path 5, and the flow controller 200 includes a control unit 7 and a storage unit 8 described later.

[0035] During analysis using the gas chromatograph 100, the opening and closing state of the gas supply flow path 3 is adjusted by the full flow valve 32, the opening and closing state of the branch flow path 4 is adjusted by the branch valve 41, and the opening and closing state of the purge flow path 5 is adjusted by the purge valve 52. The carrier gas is supplied from the gas supply flow path 3 to the sample vaporization chamber 21 of the sample introduction section 2 at a flow rate corresponding to the opening of the full flow valve 32.

[0036] The liquid sample to be analyzed is injected into the sample vaporization chamber 21 through the syringe 10. At this time, the syringe 10 penetrates the diaphragm 23 and is inserted into the sample vaporization chamber 21. In this state, the liquid sample is injected into the sample vaporization chamber 21 from the syringe 10 and the liquid sample is vaporized in the sample vaporization chamber 21 to generate a sample gas. The generated sample gas is supplied to the column 1 together with the carrier gas, and the components in the sample gas are separated in the process of passing through the column 1. The components in the separated sample gas are detected by the detector 6.

[0037] 2. Specific structure of the sample introduction part

[0038] Figure 2 2 is a schematic cross-sectional view showing a specific structure of the sample introduction section 2. The sample vaporization chamber 21 formed in the sample introduction section 2 has a vertically elongated shape. A cylindrical glass insert 24 is inserted into the sample vaporization chamber 21.

[0039] The insert 24 can be installed and removed relative to the sample vaporization chamber 21. When the insert 24 is inserted into the sample vaporization chamber 21, a space 25 is formed between the inner surface of the sample vaporization chamber 21 and the outer surface of the insert 24, and the space 25 constitutes a gas flow path. That is, the carrier gas supplied from the gas supply flow path 3 to the sample vaporization chamber 21 passes through the insert 24 from the upper end to the lower end, and then flows upward from the lower end of the insert 24 through the space 25 outside the insert 24, and flows out to the branch flow path 4.

[0040] A filling material 26 composed of an adsorbent is filled at a predetermined filling position (e.g., the center portion) in the insert 24. The filling material 26 is formed of a material having high adsorption properties, such as wool. When the liquid sample is injected by the syringe 10, the tip of the syringe 10 inserted into the sample vaporization chamber 21 approaches or contacts the filling material 26, and the liquid sample is injected into the filling material 26 from the tip of the syringe 10.

[0041] Since there is no fixture for fixing the packing material 26, when an external force is applied to the packing material 26, if the external force is greater than the friction force, the packing material 26 may be displaced from the filling position. When the tip of the syringe 10 inserted into the sample vaporization chamber 21 is not sufficiently close to or in contact with the packing material 26 during the injection of the liquid sample due to the packing material 26 being displaced from the filling position, the liquid sample is not uniformly vaporized, and the analysis reproducibility may be reduced. In addition, in some cases, the sample vaporization chamber 21 is filled with a catalyst used in a thermal desorption tube or a methane reformer as a packing material. Even in such a structure, the analysis reproducibility may be reduced due to the displacement of the packing material.

[0042] 3. Electrical structure of gas chromatograph

[0043] Figure 3 2 is a block diagram showing the electrical structure of the gas chromatograph 100. The flow controller 200 includes, for example, a control unit 7 including a CPU (Central Processing Unit), and the control unit 7 is electrically connected to a flow sensor 31, a full flow valve 32, a diverter valve 41, an inlet pressure sensor 51, a purge valve 52, a purge pressure sensor 53, and a storage unit 8. The storage unit 8 includes a RAM (Random Access Memory) or a ROM (Read Only Memory), etc.

[0044] The control unit 7 controls the openings of the full flow valve 32, the diverter valve 41, and the purge valve 52 based on the input signals from the flow sensor 31, the inlet pressure sensor 51, and the purge pressure sensor 53. At this time, the control unit 7 appropriately compares the input signals from the flow sensor 31, the inlet pressure sensor 51, and the purge pressure sensor 53 with the threshold values ​​stored in the storage unit 8, and controls the openings of the full flow valve 32, the diverter valve 41, and the purge valve 52 based on the comparison result.

[0045] The control unit 7 is electrically connected to the operating unit 9. The operating unit 9 includes a keyboard or a mouse, and an operator such as a user can perform input operations by operating the operating unit 9. For example, the above threshold value may be stored in the storage unit 8 by the operator operating the operating unit 9.

[0046] 4. Control of diverter valve

[0047] Figure 4 2 is a flowchart showing an example of processing performed by the control unit 7 when controlling the flow dividing valve 41. Next, the control of the opening degree of the flow dividing valve 41 performed by the control unit 7 when stopping the operation of the gas chromatograph 100 will be described.

[0048] For example, when the gas chromatograph 100 is shut down, when the gas chromatograph 100 is abnormal, or when the gas chromatograph 100 is self-diagnosed, a command for requesting to stop the operation of the flow controller 200 is generated. This command may be generated based on the operation of the operation unit 9 or may be automatically generated based on input signals from various sensors.

[0049] "When the device is shut down" means when the gas chromatograph 100 is stopped, and this "when the device is shut down" includes shutting down by cutting off the power supply of the gas chromatograph 100. In addition, "when an abnormality occurs" includes not only when an abnormality occurs inside the gas chromatograph 100, but also when an abnormality occurs in other devices (pretreatment devices, etc.) connected to the gas chromatograph 100. "Abnormality" is a concept that includes all defects of the device, such as gas leakage, detection failure or high temperature state. "Device self-diagnosis" refers to the action used to diagnose the operating state (including abnormal state) of the gas chromatograph 100 or other devices connected to the gas chromatograph 100.

[0050] When the operation of the flow controller 200 is stopped, the sample vaporization chamber 21 is pressurized by the inflow of the carrier gas and becomes a high pressure state. When there is a request to stop the operation of the flow controller 200 (step S1: "Yes"), the control unit 7 opens the bypass valve 41 (step S2) to discharge the sample gas in the sample vaporization chamber 21 from the bypass flow path 4.

[0051] At this time, the control unit 7 controls the opening of the diverter valve 41 in such a way that the pressure in the sample vaporization chamber 21 decreases with a first pressure gradient (step S3). The first pressure gradient is a pressure gradient that is smaller than the pressure gradient that causes the filling material of the gas chromatograph 100 to shift from the filling position when the sample gas in the sample vaporization chamber 21 is discharged from the diverter flow path 4. The deviation of the filling material from the filling position can be allowed as long as it is within the range that does not affect the analysis results (analysis reproducibility, etc.) or within the range that the constituent components (diverter valve 41, etc.) do not fail. That is, the first pressure gradient can also be set within the above-mentioned deviation range. In addition, the "gradient" in the present invention is not limited to the gradient of a straight line, but is a concept that also includes the gradient of a curve.

[0052] The above-mentioned filling material includes a filling material such as the filling material 26 that is filled at a filling position in the sample vaporization chamber 21, or a filling material such as the filling material 421 that is filled at a filling position in the branch flow path 4. The filling position of the filling material can be any filling position as long as it is in the sample vaporization chamber 21 or in the branch flow path 4, and is not limited to the filling position of each filling material 26 or 421.

[0053] The pressure control performed by the control unit 7 with the first pressure gradient continues until the pressure in the sample vaporization chamber 21 detected by the inlet pressure sensor 51 becomes equal to or lower than a threshold value. The threshold value is a pressure greater than the atmospheric pressure, and is a pressure at which the filling material does not deviate (does not move) from the filling position even if the opening of the diverter valve 41 is subsequently increased (for example, fully opened).

[0054] The above threshold value may also be stored in advance in the storage unit 8 by the operator operating the operation unit 9. For example, after the operator performs an operation for determining the threshold value, an appropriate threshold value may be stored in the storage unit 8. Specifically, the pressure at which the filling material deviates from the filling position when the diverter valve 41 is fully opened may be determined by switching the diverter valve 41 to fully open multiple times at different times, and a pressure equal to or slightly higher than the pressure may be stored in the storage unit 8 as a threshold value.

[0055] The first pressure gradient (dp / dt) can be calculated, for example, by the following equation (1).

[0056] dpd t=F×PsV(1)

[0057] In addition, F is the limiting flow rate, Ps is the standard atmospheric pressure (101.325 kPa), and V is the volume of the control system. The limiting flow rate is a flow rate that does not cause the filling material to deviate from the filling position, for example, 500 ml / min to 700 ml / min, more specifically about 600 ml / min, but the limiting flow rate is appropriately set according to the type of filling material and the filling position. In this way, the first pressure gradient can be calculated based on the limiting flow rate, but the calculation formula of the first pressure gradient is not limited to formula (1).

[0058] When the pressure control performed by the first pressure gradient is maintained (step S3) and the pressure in the sample vaporization chamber 21 detected by the inlet pressure sensor 51 becomes less than the threshold value (step S4: "Yes"), the control unit 7 controls the opening of the diverter valve 41 in such a manner that the pressure in the sample vaporization chamber 21 is reduced by a second pressure gradient greater than the first pressure gradient (step S5). The second pressure gradient is, for example, a pressure gradient when the opening of the diverter valve 41 is controlled so that the flow path resistance of the diverter valve 41 is minimized (when fully opened). However, the second pressure gradient is preferably a pressure gradient when the diverter valve 41 is fully opened, but any pressure gradient may be used as long as the flow path resistance of the diverter valve 41 can be minimized, and is not limited to being fully opened.

[0059] The pressure control performed by the control unit 7 with the second pressure gradient is performed at least until the pressure in the sample vaporization chamber 21 detected by the inlet pressure sensor 51 reaches the atmospheric pressure. The pressure control performed with the second pressure gradient may be terminated based on the input signal from the inlet pressure sensor 51, or may be terminated at a time point when a certain time sufficient for the pressure in the sample vaporization chamber 21 to reach the atmospheric pressure has passed.

[0060] 5. Comparison of pressure changes in the sample vaporization chamber

[0061] Figure 5A : is a diagram showing an example of pressure change when the target value of the pressure control in the sample vaporization chamber 21 by the control unit 7 is maintained at a constant gradient. Figure 5B This is a diagram showing an example of pressure change when the gradient of the target value of the pressure control in the sample vaporization chamber 21 performed by the control unit 7 is switched during the process.

[0062] exist Figure 5A In the example of FIG. 4 , the following situation is shown: the control unit 7 controls the opening of the diverter valve 41 so that the target value of the inlet pressure decreases at a certain gradient. Figure 5A As shown in FIG. 1 , when the target value of the inlet pressure is reduced at a constant gradient, the pressure gradient of the inlet pressure detected by the inlet pressure sensor 51 becomes a constant value of a straight line until the inlet pressure drops below the specified value. However, when the inlet pressure drops below the specified value, due to the flow path resistance of the components such as the flow dividing valve 41 and the flow dividing filter 42, the target value of the inlet pressure and the inlet pressure (actually measured value) detected by the inlet pressure sensor 51 diverge.

[0063] In contrast, when the pressure control of the inlet pressure is switched from the first pressure gradient to the second pressure gradient as in the present embodiment, the Figure 5BAs shown in the figure, the gradient of the target value of the inlet pressure is switched before the inlet pressure drops to a predetermined value where the target value of the inlet pressure deviates from the actual value. Thus, until the gradient of the target value of the inlet pressure is switched, the pressure gradient of the inlet pressure detected by the inlet pressure sensor 51 becomes a linear constant value (first pressure gradient).

[0064] Thereafter, the target value of the inlet pressure is switched to the atmospheric pressure. In this case, the opening of the diverter valve 41 may be controlled not based on the inlet pressure detected by the inlet pressure sensor 51, but the diverter valve 41 may be controlled to be fully opened. By switching the pressure control of the inlet pressure to the second pressure gradient greater than the first pressure gradient in this way, the gas in the sample vaporization chamber 21 can be discharged quickly.

[0065] 6. Modifications

[0066] The pressure control performed by the control unit 7 with the first pressure gradient is not limited to a structure in which the pressure in the sample vaporization chamber 21 detected by the inlet pressure sensor 51 is maintained until it becomes less than a threshold value, and may be maintained for a certain time, for example. In this case, the certain time may be arbitrarily set by the operator or calculated by the control unit 7 based on the history of input signals from the sensors (the inlet pressure sensor 51, etc.) in the past.

[0067] In addition, a configuration may be adopted in which the pressure control with the second pressure gradient by the control unit 7 is omitted and only the pressure control with the first pressure gradient is performed. That is, the pressure control with the first pressure gradient by the control unit 7 may be maintained until the pressure in the sample vaporization chamber 21 detected by the inlet pressure sensor 51 reaches the atmospheric pressure.

[0068] 7. Method

[0069] It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0070] (Item 1) A gas chromatograph according to one embodiment may include:

[0071] a sample vaporization chamber, wherein the liquid sample is vaporized inside the sample vaporization chamber to generate a sample gas;

[0072] A shunt flow path, which is used to discharge the sample gas in the sample vaporization chamber;

[0073] a valve provided in the branch flow path, the valve opening and closing to adjust the flow rate of the sample gas flowing in the branch flow path;

[0074] a filling material which is filled at a filling position in the sample vaporization chamber or a filling position in the branch flow path; and

[0075] The control unit controls the opening of the valve so that the pressure in the sample vaporization chamber decreases by a pressure gradient smaller than a pressure gradient causing the filling material to deviate from the filling position when the sample gas in the sample vaporization chamber is discharged from the branch flow path.

[0076] According to the gas chromatograph described in the first aspect, the filling material in the sample vaporization chamber or the branch flow channel can be prevented from shifting from the filling position by controlling the opening of the valve when the sample gas in the sample vaporization chamber is discharged from the branch flow channel.

[0077] (Item 2) In the gas chromatograph described in Item 1, it may be,

[0078] A pressure sensor is further provided, the pressure sensor detecting the pressure in the sample vaporization chamber.

[0079] The control unit controls the opening of the valve in a manner such that the pressure in the sample vaporization chamber decreases by a first pressure gradient that is smaller than the pressure gradient that causes the filling material to shift from the filling position until the pressure in the sample vaporization chamber detected by the pressure sensor becomes equal to or less than a threshold value, and then controls the opening of the valve in a manner such that the pressure in the sample vaporization chamber decreases by a second pressure gradient that is larger than the first pressure gradient.

[0080] According to the gas chromatograph described in the second item, the filling material in the sample vaporization chamber or the branch flow path can be prevented from shifting from the filling position by performing pressure control with a first pressure gradient until the pressure in the sample vaporization chamber detected by the pressure sensor becomes below a threshold value. Thereafter, the gas in the sample vaporization chamber can be discharged more quickly by performing pressure control with a second pressure gradient greater than the first pressure gradient.

[0081] (Item 3) In the gas chromatograph described in Item 2, it may be,

[0082] The second pressure gradient is a pressure gradient when the opening of the valve is controlled so that the flow path resistance of the valve is minimized.

[0083] According to the gas chromatograph described in the third aspect, after the pressure control in the sample vaporization chamber is switched from the first pressure gradient to the second pressure gradient, the exhaust of the gas in the sample vaporization chamber can be accelerated as much as possible.

[0084] (Item 4) In the gas chromatograph described in Item 1, it may be,

[0085] The filling material is filled in a filling position in an insert member provided in the sample vaporization chamber.

[0086] According to the gas chromatograph described in the fourth aspect, it is possible to prevent the filling material filled in the insert member provided in the sample vaporization chamber from shifting from the filling position.

[0087] (Item 5) In the gas chromatograph described in Item 1, it may be,

[0088] A filter is also provided, wherein the filter is arranged at a filling position in the branch flow path,

[0089] The filler material is filled in the filter.

[0090] According to the gas chromatograph described in Item 5, it is possible to prevent the filling material filled in the filter provided in the branch flow channel from being displaced from the filling position.

[0091] Description of Reference Numerals

[0092] 1: column; 2: sample introduction part; 3: gas supply flow path; 4: bypass flow path; 5: purge flow path; 6: detector; 7: control part; 21: sample vaporization chamber; 24: insert; 26: filling material; 41: bypass valve; 42: bypass filter; 51: inlet pressure sensor; 100: gas chromatograph; 200: flow controller; 421: filling material.

Claims

1. A gas chromatograph comprising: a sample vaporization chamber, wherein the liquid sample is vaporized inside the sample vaporization chamber to generate a sample gas; A shunt flow path, which is used to discharge the sample gas in the sample vaporization chamber; a valve provided in the branch flow path, the valve opening and closing to adjust the flow rate of the sample gas flowing in the branch flow path; a filling material which is filled at a filling position in the sample vaporization chamber or a filling position in the branch flow path; and The control unit controls the opening of the valve so that the pressure in the sample vaporization chamber decreases by a pressure gradient smaller than a pressure gradient causing the filling material to deviate from the filling position when the sample gas in the sample vaporization chamber is discharged from the branch flow path.

2. The gas chromatograph according to claim 1, wherein: A pressure sensor is further provided, the pressure sensor detecting the pressure in the sample vaporization chamber. The control unit controls the opening of the valve in a manner such that the pressure in the sample vaporization chamber decreases by a first pressure gradient that is smaller than the pressure gradient that causes the filling material to shift from the filling position until the pressure in the sample vaporization chamber detected by the pressure sensor becomes equal to or less than a threshold value, and then controls the opening of the valve in a manner such that the pressure in the sample vaporization chamber decreases by a second pressure gradient that is larger than the first pressure gradient.

3. The gas chromatograph according to claim 2, wherein: The second pressure gradient is a pressure gradient when the opening of the valve is controlled so that the flow path resistance of the valve is minimized.

4. The gas chromatograph according to claim 1, wherein: The filling material is filled in a filling position in an insert member provided in the sample vaporization chamber.

5. The gas chromatograph according to claim 1, wherein: A filter is also provided, wherein the filter is arranged at a filling position in the branch flow path, The filler material is filled in the filter.

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