Gas Analysis Systems

Abstract

A gas analysis system (1) comprises: a first flow path (L1) through which sample gas that has passed through columns (41, 42) using helium gas as carrier gas flows; a second flow path (L2) through which the sample gas that has passed through columns (43, 44) using nitrogen gas as carrier gas flows; a TCD (90) that detects components of gas using the difference in thermal conductivity between the components; and a switching module (M3). The switching module (M3) is disposed between the first flow path (L1), the second flow path (L2), and the TCD (90), and is configured to be switchable between a first state in which the TCD (90) is connected to the first flow path (L1) and a second state in which the TCD (90) is connected to the second flow path (L2).

Description

[Technical Field]

[0001] The present disclosure relates to a gas analysis system (gas chromatograph system) equipped with a thermal conductivity detector (hereinafter also referred to as "TCD"). [Background technology]

[0002] Some gas analysis systems use TCD to detect components in gas. In gas analysis systems that use TCD to detect components in gas, if the difference between the thermal conductivity of the sample gas component to be detected and the thermal conductivity of the carrier gas is small, the intensity of the detection signal corresponding to the sample gas component will be small, resulting in reduced sensitivity.

[0003] To address this issue, a conventional gas analysis system has been proposed in which a first system including a separation column and a TCD through which a first carrier gas flows, and a second system including a separation column and a TCD through which a second carrier gas with a different composition from the first carrier gas flows, are separately provided, and components with a small difference in thermal conductivity from the first carrier gas are detected by the TCD in the second system through which the second carrier gas flows (see Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Agilent Technologies, Inc. Application Note Publication No. 5989-7438JAJP "GC Analysis of Refinery Gas (RGA)" Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional gas analysis system disclosed in the above-mentioned Non-Patent Document 1 requires two TCDs for each of the two types of carrier gas, which causes a problem of the overall system becoming large.

[0006] The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a gas analysis system that can sequentially detect components in a first carrier gas and components in a second carrier gas that is a different type from the first carrier gas using a single thermal conductivity detector. [Means for solving the problem]

[0007] The gas analysis system according to the present disclosure comprises a first column and a second column, each of which separates gas components contained in a sample gas; a first supply source and a second supply source, each of which supplies a first carrier gas and a second carrier gas, which are different from each other, for transporting the sample gas; a first flow path through which the sample gas flows after passing through the first column by the first carrier gas; a second flow path through which the sample gas flows after passing through the second column by the second carrier gas; a thermal conductivity detector that detects components in the gas by utilizing differences in thermal conductivity of each component; and a switching device, which is disposed between the first flow path, the second flow path, and the thermal conductivity detector, and is configured to be switchable between a first state in which the thermal conductivity detector is connected to the first flow path and a second state in which the thermal conductivity detector is connected to the second flow path.

[0008] According to the gas analysis system, a switching device is disposed between the first flow path, the second flow path, and the thermal conductivity detector. The connection of the thermal conductivity detector can be switched from one of the first flow path and the second flow path to the other by switching the state of the switching device from one of the first state and the second state to the other. Therefore, while maintaining the carrier gas flowing through the first column as the first carrier gas and the carrier gas flowing through the second column as the second carrier gas, the carrier gas supplied to the thermal conductivity detector can be switched from one of the first carrier gas and the second carrier gas to the other. As a result, components in the first carrier gas and components in the second carrier gas can be sequentially detected by a single thermal conductivity detector. [Effects of the Invention]

[0009] According to the present disclosure, a gas analysis system can be provided that can sequentially detect components in a first carrier gas and components in a second carrier gas that is a different type from the first carrier gas using a single thermal conductivity detector. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram schematically illustrating an example of the configuration of a gas analysis system. [Figure 2] FIG. 2 is a cross-sectional view of the microvalve when the microvalve is in an open state. [Figure 3] FIG. 2 is a cross-sectional view of the microvalve when the microvalve is in a closed state. [Figure 4] FIG. 1 is a diagram (part 1) showing the state of the switching valve and the flow of each gas. [Figure 5] FIG. 2 is a diagram (part 2) showing the state of the switching valve and the flow of each gas. [Figure 6] FIG. 3 is a diagram (part 3) showing the state of the switching valve and the flow of each gas. [Figure 7] FIG. 4 is a diagram (part 4) showing the state of the switching valve and the flow of each gas. [Figure 8] FIG. 5 is a diagram (part 5) showing the state of the switching valve and the flow of each gas. [Figure 9] FIG. 6 is a diagram (part 6) showing the state of the switching valve and the flow of each gas. [Figure 10] This is a diagram (part 7) showing the state of the switching valve and the flow of each gas. [Figure 11] This is a diagram (part 8) showing the state of the switching valve and the flow of each gas. [Figure 12] FIG. 1 is a diagram schematically illustrating an example of the configuration of an analysis device. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present embodiment will now be described in detail with reference to the drawings, in which the same or corresponding parts in the drawings are designated by the same reference numerals and description thereof will not be repeated.

[0012] [Overall system configuration] FIG. 1 is a diagram schematically illustrating an example of the configuration of a gas analysis system (gas chromatograph system) 1 according to this embodiment.

[0013] The gas analysis system 1 includes an analyzer 10, an input device 60, a display device 70, and a control device 100. The analyzer 10 includes carrier gas supply devices 11a to 11c, 12a to 12c, a sample tank 20, a pump 21, vents 23 to 26, sampler modules M1 and M2, a switching module M3, columns 41 to 44, a first flow path L1, a second flow path L2, and a detection device 80.

[0014] Each of the carrier gas supply devices 11a-11c and 12a-12c adjusts the pressure of a mobile phase called a carrier gas to a predetermined value and outputs the adjusted pressure. The carrier gas supply devices 11a-11c and the carrier gas supply devices 12a-12c output different types of carrier gas. In this embodiment, the carrier gas supply devices 11a-11c output helium gas (He) as a first type of carrier gas, and the carrier gas supply devices 12a-12c output nitrogen gas (N2) as a second type of carrier gas.

[0015] The sample tank 20 is a device for storing sample gas to be analyzed, and is connected to the sampler modules M1 and M2.

[0016] The pump 21 is a suction pump connected to the flow paths in the sampler modules M1 and M2, and serves to suck out air from the sampler modules M1 and M2 to create a negative pressure inside the sampler modules M1 and M2. Note that the negative pressure here refers to a pressure lower than atmospheric pressure.

[0017] Vents 23 to 26 connect the flow paths within analyzer 10 to the outside, and discharge gas within analyzer 10 to the outside.

[0018] Each of the sampler modules M1, M2 and the switching module M3 is formed by mounting multiple switching valves on a flow path plate (flow path member) on which a flow path pattern is formed. Each of the modules M1 to M3 is provided with multiple connectors (interfaces) for connecting external devices. The flow paths formed in each of the modules M1 to M3 are connected to the outside via these connectors.

[0019] The sampler module M1 is a device for supplying a constant amount of sample gas to the column 41 using helium gas (He) as a carrier gas. The sampler module M1 includes connectors C1 to C6, a constant-volume sample loop PL1, switching valves V1 to V6, and a plurality of flow paths connecting these.

[0020] The connectors C1 to C3 are respectively connected to a sample tank 20, a pump 21, and a vent 23. The connectors C4 and C5 are respectively connected to carrier gas supply devices 11a and 11b. The connector C6 is connected to a column 41.

[0021] The switching valves V1 and V4 are arranged in this order in the flow path from the connector C1 to the connector C4. The switching valves V3, V5, and V6 are arranged in this order in the flow path from the connector C2 to the connector C5. The switching valve V2 is arranged in the flow path connecting the flow path between the switching valves V5 and V6 and the connector C3.

[0022] The sample loop PL1 is disposed in a flow path connecting the flow path between the switching valves V1 and V4 and the flow path between the switching valves V3 and V5. The sample loop PL1 has the function of temporarily holding the sample gas introduced from the sample tank 20 in order to supply it to the column 41. By appropriately switching the connection destination of the sample loop PL1 under the control of the switching valves V1 to V6, the sampler module M1 temporarily fills the sample loop PL1 with the sample gas supplied from the sample tank 20, and then supplies the sample gas filled in the sample loop PL1 to the column 41 using helium gas (He) as a carrier gas.

[0023] The columns 41 and 42 are arranged in series in this order between the connector C3 of the sampler module M1 and the first flow path L1. The columns 41 and 42 separate and output various components contained in the sample gas in the time direction as the supplied sample gas passes through each column with the flow of carrier gas. The column 41 is a pre-column for primary separation, and the column 42 is a main column for secondary separation. The carrier gas supply device 11c is connected to the flow path between the columns 41 and 42.

[0024] The first flow path L1 connects the column 42 and the connector C13 of the switching module M3. The first flow path L1 supplies the gas components flowing out of the column 42 to the switching module M3 using helium gas (He) as a carrier gas.

[0025] The sampler module M2 is a device that uses nitrogen gas (N2) as a carrier gas to supply a constant amount of sample gas to the column 43. The sampler module M2 includes connectors C7 to C12, a constant-volume sample loop PL2, switching valves V7 to V12, and a plurality of flow paths that connect these.

[0026] The connectors C7 to C9 are respectively connected to a sample tank 20, a pump 21, and a vent 24. The connectors C10 and C11 are respectively connected to carrier gas supply devices 12a and 12b. The connector C12 is connected to a column 43.

[0027] The switching valves V7 and V10 are arranged in this order in the flow path from the connector C7 to the connector C10. The switching valves V9, V11, and V12 are arranged in this order in the flow path from the connector C8 to the connector C11. The switching valve V8 is arranged in the flow path connecting the flow path between the switching valves V11 and V12 and the connector C9.

[0028] The sample loop PL2 is disposed in a flow path connecting the flow path between the switching valves V7 and V10 and the flow path between the switching valves V9 and V11. The sample loop PL2 has the function of temporarily holding the sample gas introduced from the sample tank 20 in order to supply it to the column 41. By appropriately switching the connection destination of the sample loop PL2 under the control of the switching valves V7 to V12, the sampler module M2 temporarily fills the sample loop PL2 with the sample gas supplied from the sample tank 20, and then supplies the sample gas filled in the sample loop PL2 to the column 43 using nitrogen gas (N2) as a carrier gas.

[0029] Columns 43 and 44 are arranged in series in this order between connector C12 of sampler module M2 and second flow path L2. Columns 43 and 44 separate and output various components contained in the supplied sample gas in the time direction while the sample gas passes through each column with the flow of carrier gas. Column 43 is a pre-column for primary separation, and column 44 is a main column for secondary separation. Carrier gas supply device 12c is connected to the flow path between columns 43 and 44.

[0030] The second flow path L2 connects the column 44 and the connector C14 of the switching module M3. The second flow path L2 supplies the gas components flowing out of the column 44 to the switching module M3 using nitrogen gas (N2) as a carrier gas.

[0031] The switching module M3 is a device that switches the detection target of the detection device 80 between the gas components in the helium gas flowing through the first flow path L1 and the gas components in the nitrogen gas flowing through the second flow path L2.

[0032] The switching module M3 includes connectors C13 to C16, switching valves V13 to V16, and a plurality of flow paths connecting these. The first flow path L1 and the second flow path L2 are connected to the connectors C13 and C14, respectively. The vent 25 is connected to the connector C15. The detection device 80 is connected to the connector C16.

[0033] The switching valve V13 is disposed in a flow path connecting the flow path between the connector C15 and the switching valve V15 and the flow path between the connector C13 and the switching valve V16. The switching valve V14 is disposed in a flow path connecting the flow path between the connector C16 and the switching valve V16 and the flow path between the connector C14 and the switching valve V15. The switching valve V15 is disposed in a flow path between the connector C14 and the connector C15. The switching valve V16 is disposed in a flow path between the connector C13 and the connector C16.

[0034] The switching module M3 is switched between a first state and a second state by switching the combination of open / closed states of the switching valves V13 to V16. When the switching module M3 is in the first state, the first flow path L1 and the detection device 80 are connected to each other, so that gas (helium gas) from the first flow path L1 is supplied to the detection device 80, and the second flow path L2 is connected to the vent 25, so that gas (nitrogen gas) from the second flow path L2 is discharged to the outside. When the switching module M3 is in the second state, the second flow path L2 and the detection device 80 are connected to each other, so that gas (nitrogen gas) from the second flow path L2 is supplied to the detection device 80, and the first flow path L1 is connected to the vent 25, so that gas (helium gas) from the first flow path L1 is discharged to the outside.

[0035] The switching valves V1 to V16 can be controlled independently of each other in response to a command from the control device 100.

[0036] The detection device 80 is connected to the connector C16 of the switching module M3 and detects the gas components supplied from the switching module M3. The detection device 80 includes automatic pressure controllers (hereinafter also referred to as "APC") 81 and 82, switching valves SW1 and SW2, and a TCD (Thermal Conductivity Detector) 90.

[0037] The APC 81 outputs helium gas at a constant pressure as the reference gas for the TCD 90. The APC 82 outputs nitrogen gas at a constant pressure as the reference gas for the TCD 90. The switching valves SW1 and SW2 switch the reference gas supplied to the TCD 90 between helium gas from the APC 81 and nitrogen gas from the APC 82.

[0038] When the switching module M3 is in the first state, helium gas from the first flow path L1 is introduced as a carrier gas into the TCD 90. In this case, the switching valves SW1 and SW2 are controlled so that the reference gas supplied to the TCD 90 is also helium gas.

[0039] When the switching module M3 is in the second state, nitrogen gas from the second flow path L2 is introduced as a carrier gas into the TCD 90. In this case, the switching valves SW1 and SW2 are controlled so that the reference gas supplied to the TCD 90 is also nitrogen gas.

[0040] The TCD 90 detects various components in the sample gas introduced from the switching module M3 by utilizing the differences in thermal conductivity of each component while using a reference gas as a comparison. Component detection methods that utilize differences in thermal conductivity are well known, so a detailed description will be omitted.

[0041] Nitrogen gas is used as the carrier gas when detecting hydrogen and helium in the sample gas. Hydrogen and helium are lighter than other components and are eluted earlier than other components, regardless of the separation column used. Therefore, when the analysis begins, nitrogen gas is used as the carrier gas, and after the timing for detecting hydrogen and helium has passed, the carrier gas is immediately switched to helium gas. Since components other than hydrogen and helium have much lower thermal conductivity than helium, switching the carrier gas to helium gas can increase the detection sensitivity of components other than hydrogen and helium.

[0042] Data indicating the detection results by the TCD 90 is stored in the memory within the control device 100 and is displayed on the display device 70 upon request from the user.

[0043] The input device 60 is, for example, a keyboard or a pointing device such as a mouse, and receives commands from the user. The display device 70 is, for example, configured with a liquid crystal display (LCD) panel, and displays information to the user. When a touch panel is used as the user interface, the input device 60 and the display device 70 are integrally formed.

[0044] The control device 100 includes a central processing unit 110, a storage device 120, an interface, etc. The control device 100 comprehensively controls the entire analysis device 10. The control device 100 is connected to an input device 60 and a display device 70, which are user interfaces, by wire or wirelessly.

[0045] [Configuration of switching valves V1 to V16] An example of the configuration of the switching valves V1 to V16 according to this embodiment will be described using Figures 2 and 3. Since the switching valves V1 to V16 have the same basic configuration, the switching valves V1 to V16 will be described as microvalve 200 without distinction in Figures 2 and 3.

[0046] Figure 2 is a cross-sectional view of the microvalve 200 when the microvalve 200 is in an open state. Figure 3 is a cross-sectional view of the microvalve 200 when the microvalve 200 is in a closed state.

[0047] The microvalve 200 has a layered structure including a base layer 220, a diaphragm layer 230, and a cover layer 240, which are stacked in this order. Each of the base layer 220, the diaphragm layer 230, and the cover layer 240 is made of, for example, silicon oxide or single-crystal silicon to achieve the desired strength, flexibility, and low activity, and is microfabricated using MEMS (Micro Electric Mechanical Systems) technology.

[0048] The thickness (dimension in the stacking direction) of the microvalve 200 is approximately 1 to 2 mm. For convenience, in the following description, the direction from the base layer 220 toward the cover layer 240 may be referred to as the upward direction, and the direction from the cover layer 240 toward the base layer 220 may be referred to as the downward direction.

[0049] The base layer 220 is disposed as the bottom layer of the microvalve 200. The base layer 220 has a recess 221 and openings 222 to 224 formed therein. The recess 221 has a substantially circular shape when the base layer 220 is viewed in plan from above, and is formed near the approximate center of the base layer 220. The recess 221 is recessed from the upper surface side to the lower surface side of the base layer 220. The thickness of the base layer 220 is approximately 150 μm. The depth of the recess 221 is 5 to 20 μm, and preferably approximately 10 μm.

[0050] The openings 223 and 224 are formed in the bottom 225 of the recess 221. As will be described later, the openings 223 and 224 form an inlet and an outlet for the sample gas, respectively. The opening 222 is formed on the outer edge of the periphery of the recess 221 of the base layer 220, spaced apart from the recess 221. The opening 222 forms a supply port for a control fluid (pneumatic fluid) for the microvalve 200.

[0051] Diaphragm layer 230 is disposed on the upper surface side of base layer 220, facing base layer 220. Diaphragm layer 230 has an opening 232 penetrating diaphragm layer 230, a rigid portion 234, and a flexible portion 233 provided around rigid portion 234. Flexible portion 233 is thinner than rigid portion 234 and has flexibility. Elastic deformation of flexible portion 233 causes rigid portion 234 to be displaced in the vertical direction.

[0052] The opening 232 is formed at a distance from the flexible portion 233 and the rigid portion 234. When viewed in a plan view from above, the opening 232 is formed at a position overlapping the opening 222 of the base layer 220, and together with the opening 222 forms a supply port for pneumatic fluid.

[0053] The microvalve 200 is connected to a flow path member (flow path plate) 250 when in use. The flow path member 250 has openings 252 to 254 formed at positions corresponding to the openings 222 to 224 of the base layer 220, respectively. The opening 252 of the flow path member 250, the opening 222 of the base layer 220, and the opening 232 of the diaphragm layer 230 are in communication with each other, forming a supply port 262 for pneumatic fluid. The pneumatic fluid is supplied to the recess 241 of the cover layer 240 through the supply port 262.

[0054] An opening 253 of the flow path member 250 communicates with an opening 223 of the base layer 220, forming an inlet 263 for the sample gas. An opening 254 of the flow path member 250 communicates with an opening 224 of the base layer 220, forming an outlet 264 for the sample gas.

[0055] The microvalve 200 is a so-called normally open type valve that is open in the initial state (normal state) when no pneumatic fluid is supplied to the supply port 262 of the flow path member 250, and closes when pneumatic fluid is supplied to the supply port 262 of the flow path member 250.

[0056] When pneumatic fluid is not supplied to the supply port 262 of the flow path member 250, the rigid portion 234 is held away from the bottom 225 of the recess 221 in the base layer 220, as shown in Figure 2, so that the inlet 263 and outlet 264 of the sample gas are in an open state (open state) in which they are connected.

[0057] When pneumatic fluid is supplied to supply port 262 of flow path member 250, rigid portion 234 is pushed by the pneumatic fluid and displaced downward, whereby the lower surface of rigid portion 234 comes into close contact with bottom 225 of recess 221 in base layer 220, thereby blocking inlet 263 and outlet 264 for the sample gas and bringing them into a closed state. Note that instead of driving (displacing) rigid portion 234 with pneumatic fluid, rigid portion 234 may be electrically driven (displaced) using a piezoelectric element or the like.

[0058] [System analysis behavior] As described above, the gas analysis system 1 has the switching module M3 disposed between the first flow path L1 through which components flowing out of the columns 41 and 42 with helium gas as the carrier gas flow, the second flow path L2 through which components flowing out of the columns 43 and 44 with nitrogen gas as the carrier gas flow, and the detection device 80. This allows the gas analysis system 1 to sequentially supply the components eluted in the first flow path L1 and the components eluted in the second flow path L2 to the detection device 80 during one analysis without switching the carrier gas in each of the columns 41 to 44.

[0059] An example of the analytical operation of the gas analysis system 1 will be described below with reference to Figures 4 to 11. In Figures 4 to 11, switching valves marked with an x ​​are in a closed state, and switching valves not marked with an x ​​are in an open state. In Figures 4 to 11, solid arrows indicate the flow of helium gas (He gas), hollow arrows indicate the flow of nitrogen gas (N gas), and diagonal arrows indicate the flow of sample gas (sample).

[0060] During the analysis operation, the following steps 1 to 9 are performed in this order. (Step 1) Standby 4 is a diagram showing the states of the switching valves V1 to V16 and the flow of each gas during standby. During standby, the switching valves V6, V12, V13, and V14 are open, and the other switching valves are closed.

[0061] As a result, He gas from carrier gas supply device 11b passes through columns 41 and 42 and is discharged to the outside through vent 25. Also, N gas from carrier gas supply device 12b passes through columns 43 and 44, passes through the inside of TCD 90, and is discharged to the outside through vent 26. Accordingly, the reference gas for TCD 90 is N gas from APC 82.

[0062] (Step 2) Filling the sample gas Figure 5 shows the states of the switching valves V1 to V16 and the flow of each gas when sample gas is being filled. When sample gas is being filled, switching valves V1, V3, V6, V7, V9, V12, V13, and V14 are open, and the other switching valves are closed. In addition, pump 21 is activated. This allows sample gas from sample tank 20 to be filled into sample loops PL1 and PL2.

[0063] (Step 3) Pressure Equalization 6 is a diagram showing the states of the switching valves V1 to V16 and the flow of each gas when pressure is in equilibrium. When pressure is in equilibrium, the switching valves V1, V6, V7, V12, V13, and V14 are open, and the other switching valves are closed.

[0064] This brings the gas pressure in the sample loops PL1 and PL2 into equilibrium, stabilizing it at approximately atmospheric pressure, and the amount of sample gas held in the sample loops PL1 and PL2 can be stabilized at a constant level. This pressure equilibrium state continues until the gas pressure in the sample loops PL1 and PL2 stabilizes.

[0065] For ease of explanation, the sample gas filled in the sample loop PL1 will also be referred to as "He sample gas," and the sample gas filled in the sample loop PL2 will also be referred to as "N2 sample gas."

[0066] (Step 4) N2 sample gas injection 7 shows the state of the switching valves V1 to V16 and the flow of each gas when N2 sample gas is injected. When N2 sample gas is injected, switching valves V6, V10, V11, V13, and V14 are open, and the other switching valves are closed. As a result, the sample gas (N2 sample gas) in the sample loop PL2 is pushed out by the N2 gas from the carrier gas supply device 12a and injected into the column 43.

[0067] (Step 5) Pre-separation of N2 sample gas 8 shows the states of the switching valves V1 to V16 and the flow of each gas during pre-separation of the N2 sample gas. During pre-separation of the N2 sample gas, the switching valves V4, V6, V10, V11, V13, and V14 are open, and the other switching valves are closed.

[0068] As a result, the N2 sample gas injected into the column 43 is separated into a front component S1 that elutes early in the column 43 and a rear component S2 that elutes late, and the front component S1 is supplied from the column 43 to the column 44. As a result, the front component S1 of the N2 sample gas is secondarily separated in the column 43.

[0069] In parallel with the pre-separation of the N2 sample gas, the He sample gas filled in the sample loop PL1 is pushed out by the He gas from the carrier gas supply device 11a and injected into the column 41. The timing for injecting the He sample gas into the column 41 (the timing for closing the switching valve V6 and opening the switching valves V4 and V5) can be determined based on the time it takes for the front component S1 of the N2 sample gas to reach the TCD 90 and the time it takes for the baseline detected by the TCD 90 to stabilize after switching the carrier gas supplied to the TCD 90.

[0070] (Step 6) N2 sample gas component detection 9 shows the states of the switching valves V1 to V16 and the flow of each gas when detecting N2 sample gas. When detecting N2 sample gas, the switching valves V4, V5, V8, V13, and V14 are open, and the other switching valves are closed.

[0071] As a result, the front end component S1 of the N2 sample gas secondary separated in the column 44 is transported to the TCD 90 by the N2 gas from the carrier gas supply device 12c and detected.

[0072] On the other hand, the rear end component S2 of the N2 sample gas remaining in the column 43 flows backward through the column 43 with the N2 gas from the carrier gas supply device 12c and is discharged to the outside through the vent 24.

[0073] The He sample gas injected into the column 41 is primarily separated into a front component S3 that elutes early and a rear component S4 that elutes late in the column 41, and the front component S3 is supplied from the column 41 to the column .

[0074] (Step 7) Carrier gas switching 10 is a diagram showing the states of the switching valves V1 to V16 and the flow of each gas when the gallium gas is switched. When the gallium gas is switched, the switching valves V4, V5, V8, V15, and V16 are open, and the other switching valves are closed.

[0075] As a result, the state of the switching module M3 is switched from the second state to the first state, and the gas supplied to the TCD 90 is switched from nitrogen gas from the second flow path L2 to helium gas from the first flow path L1. Accordingly, the reference gas for the TCD 90 is switched from N gas from the APC 82 to He gas from the APC 81.

[0076] (Step 8) He sample gas component detection 11 shows the states of the switching valves V1 to V16 and the flow of each gas when He sample gas is detected. When He sample gas is detected, the switching valves V2, V8, V15, and V16 are open, and the other switching valves are closed.

[0077] As a result, the front end component S3 of the He sample gas secondary separated in the column 42 is transported to the TCD 90 by the He gas from the carrier gas supply device 11c and detected.

[0078] On the other hand, the rear end component S4 of the He sample gas remaining in the column 41 flows backward through the column 41 with the He gas from the carrier gas supply device 11c and is discharged to the outside through the vent .

[0079] (Step 9) Return to standby mode Thereafter, the state returns to the standby state shown in FIG.

[0080] As described above, the gas analysis system 1 according to the present embodiment includes carrier gas supply devices 11a-11c that supply helium gas as a carrier gas, columns 41 and 42 that separate gas components contained in a sample gas using helium gas as a carrier gas, carrier gas supply devices 12a-12c that supply nitrogen gas as a carrier gas, columns 43 and 44 that separate gas components contained in a sample gas using nitrogen gas as a carrier gas, a first flow path L1 through which the sample gas flows after passing through columns 41 and 42 using helium gas as a carrier gas, a second flow path L2 through which the sample gas flows after passing through columns 43 and 44 using nitrogen gas as a carrier gas, a TCD 90 that detects components in the gas by utilizing differences in thermal conductivity among the components, and a switching module M3. The switching module M3 is disposed between the first flow path L1, the second flow path L2, and the TCD 90 and is configured to be switchable between a "first state" in which the TCD 90 is connected to the first flow path L1 and a "second state" in which the TCD 90 is connected to the second flow path L2.

[0081] Therefore, the carrier gas supplied to the TCD 90 can be switched from one of helium gas and nitrogen gas to the other while maintaining helium gas as the carrier gas flowing through columns 41 and 42 and nitrogen gas as the carrier gas flowing through columns 43 and 44. As a result, sample gas components in helium gas and sample gas components in nitrogen gas can be detected sequentially with one TCD 90.

[0082] Furthermore, the switching module M3 according to this embodiment is composed of a flow path connecting the first flow path L1, the second flow path L2, and the TCD 90, and a plurality of switching valves V13 to V16 that are provided on the flow path and can be controlled independently of each other.

[0083] Therefore, carrier gas switching can be completed more quickly than when a rotary valve with multiple ports is used as a carrier gas switching device. In other words, when a rotary valve with multiple ports is used as a carrier gas switching device, when the valve is rotated to switch the flow path, half of the ports are switched simultaneously in unison. As a result, the flow path configuration becomes complicated and the flow path volume of the surrounding piping is large, which lengthens the carrier gas replacement time when switching the carrier gas, making it difficult to stabilize the TCD90 baseline in a short time. In contrast, the switching module M3 according to this embodiment can independently control the switching valves V1 to V10, thereby simplifying the flow path configuration and reducing the flow path volume of the surrounding piping. As a result, the carrier gas replacement time is shortened, and the TCD90 baseline is stabilized more quickly, i.e., carrier gas switching can be completed more quickly.

[0084] Furthermore, each of the switching valves V13 to V16 in the switching module M3 according to this embodiment is a microvalve formed by microfabrication using MEMS technology. Specifically, each of the switching valves V13 to V16 includes a base layer 220 having an opening 223 for introducing gas into the interior and an opening 224 for discharging the gas introduced from the opening 223 to the exterior, and a diaphragm layer 230 disposed opposite the base layer 220 and elastically deforming to switch between allowing and blocking gas flow from the opening 223 to the opening 224.

[0085] By doing this, the dead volume in the flow path within the switching module M3 and inside each switching valve V13 to V16 can be made very small, thereby shortening the carrier gas replacement time and stabilizing the TCD90 baseline more quickly.

[0086] Furthermore, the switching valves V13 to V16 according to this embodiment are made of silicon. This ensures quantitative analysis accuracy. In other words, in rotary valves or general two-port on / off valves, the inner walls and seals of the flow paths are made of metal, resin, or rubber, so highly adsorbent sample gas components tend to adhere to the inner walls and seals of the flow paths. This can result in a decrease in the amount of sample gas introduced into the TCD 90, potentially leading to a decrease in quantitative analysis accuracy. In contrast, the flow path walls of the switching valves V13 to V16 according to this embodiment are all made of low-activity silicon oxide or single-crystal silicon, making it difficult for sample gas components to be adsorbed. This ensures quantitative analysis accuracy.

[0087] <Variation 1> 12 is a diagram schematically illustrating an example of the configuration of an analysis device 10A according to Modification 1. The analysis device 10A is the same as the analysis device 10 described above, except that the switching module M3 of the analysis device 10A is replaced with a rotary valve RV1. The other configuration of the analysis device 10A is the same as that of the analysis device 10 described above.

[0088] Even with this modification, the carrier gas supplied to TCD 90 can be switched from one of helium gas and nitrogen gas to the other while maintaining the carrier gas flowing through columns 41 and 42 as helium gas and the carrier gas flowing through columns 43 and 44 as nitrogen gas.

[0089] [Aspect] It will be understood by those skilled in the art that the above-described embodiments and their modifications are specific examples of the following aspects.

[0090] (Item 1) A gas analysis system according to one embodiment includes a first column and a second column, each of which separates gas components contained in a sample gas; a first supply source and a second supply source, each of which supplies a first carrier gas and a second carrier gas, which are different from each other, for transporting the sample gas; a first flow path through which the sample gas flows after passing through the first column by the first carrier gas; a second flow path through which the sample gas flows after passing through the second column by the second carrier gas; a thermal conductivity detector that detects components in the gas by utilizing differences in thermal conductivity of each component; and a switching device, which is disposed between the first flow path, the second flow path, and the thermal conductivity detector, and is configured to be switchable between a first state in which the thermal conductivity detector is connected to the first flow path and a second state in which the thermal conductivity detector is connected to the second flow path.

[0091] According to the gas analysis system described in paragraph 1, a switching device is disposed between the first flow path, the second flow path, and the thermal conductivity detector. By switching the state of the switching device from one of the first state and the second state to the other, the connection destination of the thermal conductivity detector can be switched from one of the first flow path and the second flow path to the other. Therefore, while maintaining the carrier gas flowing through the first column as the first carrier gas and the carrier gas flowing through the second column as the second carrier gas, the carrier gas supplied to the thermal conductivity detector can be switched from one of the first carrier gas and the second carrier gas to the other. As a result, components in the first carrier gas and components in the second carrier gas can be sequentially detected by a single thermal conductivity detector.

[0092] (Item 2) In the gas analysis system described in item 1, the switching device may include a flow path connecting the first flow path, the second flow path, and the thermal conductivity detector, and a plurality of valves provided on the flow path and each of which can be controlled independently of one another. The flow path may be configured to be able to establish a first state and a second state according to a combination of control states of the plurality of valves.

[0093] The gas analysis system described in paragraph 2 simplifies the flow path configuration and reduces the dead volume of the flow path compared to when a rotary valve with multiple ports is used as a carrier gas switching device, thereby shortening the carrier gas replacement time and completing carrier gas switching quickly.

[0094] (Item 3) In the gas analysis system described in item 2, each of the plurality of valves may include a base portion having an inlet for introducing gas into the interior and an outlet for discharging the gas introduced from the inlet to the outside, and a diaphragm portion disposed opposite the base portion and elastically deforming to switch between allowing and blocking the flow of gas from the inlet to the outlet.

[0095] According to the gas analysis system described in paragraph 3, the dead volume inside each valve can be made very small, thereby shortening the carrier gas replacement time and completing carrier gas switching more quickly.

[0096] (Item 4) In the gas analysis system according to item 2 or 3, each of the plurality of valves may be made of silicon.

[0097] According to the gas analysis system described in paragraph 4, the flow channel wall surface of each valve is made of silicon with low activity, so that sample gas components are less likely to be adsorbed. As a result, quantitative accuracy of the analysis can be ensured.

[0098] (Item 5) In the gas analysis system according to any one of Items 1 to 4, the first carrier gas may be helium gas, and the second carrier gas may be nitrogen gas.

[0099] According to the gas analysis system described in item 5, the type of carrier gas supplied to the thermal conductivity detector can be switched between helium gas (first carrier gas) and nitrogen gas (second carrier gas).

[0100] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0101] 1 gas analysis system, 10, 10A analyzer, 11a to 11c, 12a to 12c carrier gas supply device, 20 sample tank, 21 pump, 23 to 26 vent, 41 to 44 column, 60 input device, 70 display device, 80 detection device, 90 TCD, 100 control device, 120 memory device, 200 microvalve, 220 base layer, 221, 241 recess, 222 to 224, 232, 252 to 254 opening, 225 bottom, 230 diaphragm layer, 233 flexible part, 234 rigid part, 240 cover layer, 250 flow path member, 262 supply port, 263 inlet, 264 outlet, C1 to C16 connector, L1 first flow path, L2 second flow path, M1, M2 sampler module, M3 Switching module, PL1, PL2 sample loops, RV1 rotary valve, SW1, SW2 switching valves, V1~V16 switching valves.

Claims

1. a first column and a second column, each of which separates gas components contained in a sample gas; a first supply source and a second supply source that respectively supply a first carrier gas and a second carrier gas that are different from each other and are used to transport the sample gas; a first flow path through which the sample gas flows after passing through the first column by the first carrier gas; a second flow path through which the sample gas flows after passing through the second column by the second carrier gas; a thermal conductivity detector that detects components in a gas by utilizing the difference in thermal conductivity of each component; a switching device disposed between the first flow path, the second flow path, and the thermal conductivity detector, and configured to be switchable between a first state in which the thermal conductivity detector is connected to the first flow path, and a second state in which the thermal conductivity detector is connected to the second flow path.

2. The switching device a flow path connecting the first flow path, the second flow path, and the thermal conductivity detector; a plurality of valves provided on the flow path, each of which can be controlled independently of the others; 2. The gas analysis system according to claim 1, wherein the flow path is configured to be able to establish the first state and the second state according to a combination of control states of the plurality of valves.

3. Each of the plurality of valves is a base portion having an inlet for introducing a gas into the inside and an outlet for discharging the gas introduced from the inlet to the outside; 3. The gas analysis system according to claim 2, further comprising a diaphragm portion disposed opposite the base portion and elastically deforming to switch between flow and blocking of gas from the inlet to the outlet.

4. 4. The gas analysis system according to claim 2, wherein each of the plurality of valves is made of silicon.

5. the first carrier gas is helium gas; 2. The gas analysis system of claim 1, wherein the second carrier gas is nitrogen gas.

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