Gas analysis device and correction gas supply method

Abstract

The present application relates to a gas analysis system (1) which suppresses adsorption of a target component contained in a calibration gas in a pipe before reaching a measurement unit, and supplies the measurement unit with the calibration gas of accurate concentration. The gas analysis system (1) is provided with a measurement unit (2), a calibration gas supply unit (4) which supplies the measurement unit (2) with the calibration gas, and a control unit (76). The calibration gas supply unit (4) is provided with a source gas cylinder (44), a dilution gas cylinder (46), a confluence unit (74) which confluences the source gas and the dilution gas, a regulator (48) for adjusting the supply pressure of the source gas cylinder (44), and a flow rate adjustment mechanism (70) for controlling the supply flow rate of the dilution gas, and the supply flow rate of the source gas from the source gas cylinder (44) is adjusted only by the regulator (48). The control unit (76) adjusts the concentration of the target component in the calibration gas to a target concentration only by the flow rate adjustment mechanism (70) based on the supply pressure of the source gas which is fixed to a prescribed pressure.

Description

Technical Field

[0001] This invention relates to a gas analysis apparatus and a method for correcting gas supply. Background Technology

[0002] Various devices exist for measuring the concentration of a specific component contained in a gas, but regardless of the device, a standard curve showing the relationship between the detector signal and the concentration of the specific component is required. To generate the standard curve, the measured values ​​need to be calibrated using a calibration gas with a known concentration of the specific component (see Patent Document 1).

[0003] However, BTX (B: benzene, T: toluene, X: xylene) is a representative atmospheric pollutant, but the amount of BTX in the atmosphere is extremely small. Therefore, to measure the concentration of BTX in the atmosphere, a correction gas with a very low concentration of BTX must be used in the calibration of the measured value. On the other hand, the lower limit of the concentration of BTX source gas that can be filled into gas cylinders is usually around 10 ppm. When a correction gas with a lower concentration is required, the source gas needs to be diluted with a diluent gas such as N2 (nitrogen) to generate a correction gas of the required concentration.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-304213 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] Substances like BTX have higher boiling points than other substances (e.g., benzene has a boiling point of approximately 80°C, and xylene has a boiling point of approximately 140°C), are easily liquefied at room temperature, and readily adsorb onto the inner walls of pipelines. In particular, in gas measuring devices that measure BTX in the atmosphere, a calibration gas containing only a low concentration of the target component (such as BTX) is required. However, if adsorption of the target component occurs in the pipeline before reaching the measuring section, the concentration of the target component in the calibration gas introduced into the measuring section will be lower than the desired concentration, thus preventing accurate calibration.

[0009] Therefore, the object of the present invention is to suppress the adsorption of the target component contained in the calibration gas in the pipeline before it reaches the measuring unit, thereby supplying the measuring unit with a calibration gas of accurate concentration.

[0010] Solution to the above technical problems

[0011] In the case of generating a low-concentration correction gas by diluting a source gas containing high-boiling-point substances such as BTX, a flow controller (e.g., a mass flow controller) is typically used to control the flow rates of the source gas and the dilution gas to correspond to the desired dilution ratio. Here, the inventors have found that the flow path configuration inside the flow controller is relatively complex, and sections within the flow controller where the gas flow rate becomes extremely slow can easily form, where the target component is easily adsorbed. Therefore, the inventors proposed the following idea: by removing the flow controller from the flow path of the source gas used in the generation of the correction gas, the flow path configuration of the source gas can be simplified, and a correction gas of the desired concentration can be generated. The present invention is based on this idea. That is, the summary of the present invention is as follows.

[0012] The gas analysis apparatus of the present invention includes: a measuring unit for measuring the concentration of a target component in a gas; a calibration gas supply unit for supplying a calibration gas used in correcting the measured value of the measuring unit to the measuring unit; and a control unit for controlling the operation of the measuring unit and the calibration gas supply unit. The calibration gas supply unit includes: a source gas cylinder for supplying a source gas containing the target component at a known concentration; a dilution gas cylinder for supplying a dilution gas for diluting the source gas; a merging unit for merging the source gas supplied from the source gas cylinder and the dilution gas supplied from the dilution gas cylinder to generate the calibration gas; a regulator disposed between the source gas cylinder and the merging unit for regulating the supply pressure of the source gas supplied from the source gas cylinder to the merging unit; and a flow rate regulating mechanism disposed between the dilution gas cylinder and the merging unit for controlling the flow rate of the dilution gas supplied from the dilution gas cylinder to the merging unit. The supply flow rate of the source gas from the source gas cylinder is regulated only by the regulator. The control unit is configured such that, when the calibration gas is supplied from the calibration gas supply unit to the measuring unit, while the supply pressure of the source gas is fixed at a predetermined pressure independent of the target concentration of the target component in the calibration gas by the regulator, the concentration of the target component in the calibration gas is adjusted to the target concentration solely by the flow regulating mechanism based on the supply pressure of the source gas, which is fixed at the predetermined pressure. The gas analysis device is configured to extract only the flow rate required for analysis from the calibration gas adjusted to the target concentration in the confluence section, and use it in the measurement of the measuring unit.

[0013] The calibration gas supply method of the present invention is a method of generating a calibration gas by merging a source gas containing a target component at a known concentration and a dilution gas for diluting the source gas in a merging section, and supplying the calibration gas to a measuring section for measuring the concentration of the target component in the gas. The method comprises the following steps in sequence: a source gas supply step, in which the source gas is supplied to the confluence section while the supply pressure of the source gas from the source gas cylinder supplied with the source gas is fixed at a predetermined pressure by a regulator; a flow rate calculation step, in which the necessary flow rate of the diluent gas is calculated based on the supply pressure of the source gas from the source gas cylinder, which is fixed at the predetermined pressure, to make the concentration of the target component in the calibration gas generated in the confluence section reach the target concentration; a flow rate control step, in which the supply flow rate of the diluent gas from the diluent gas cylinder is controlled by a flow rate regulating mechanism so that the flow rate of the diluent gas supplied from the diluent gas cylinder to the confluence section becomes the necessary flow rate calculated in the flow rate calculation step; and a calibration gas extraction step, in which the predetermined flow rate of the calibration gas in the confluence section, in which the concentration of the target component is adjusted to the target concentration, is extracted for measurement in the measurement unit.

[0014] Invention Effects

[0015] In the gas analysis apparatus of the present invention, a method is employed to adjust the concentration of the target component in the calibration gas supplied from the calibration gas supply unit to the measurement unit to a target concentration by fixing the supply pressure of the source gas containing the target component while controlling the flow rate of the dilution gas. With this configuration, since there is no flow controller in the flow path of the source gas, the target component will not be adsorbed into the flow controller's pipes, and a calibration gas of accurate concentration can be supplied to the measurement unit.

[0016] In the calibration gas supply method of the present invention, when supplying calibration gas to the measuring unit, the supply pressure of the source gas is fixed only by a regulator, and the flow rate of the dilution gas is controlled by a flow regulating mechanism, thereby adjusting the concentration of the target component of the calibration gas to the target concentration. Therefore, it is unnecessary to install a flow controller in the flow path of the source gas, preventing the target component from adsorbing into the flow controller's pipeline, and enabling the supply of calibration gas of accurate concentration to the measuring unit. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating one embodiment of a gas analysis system.

[0018] Figure 2 This is a diagram illustrating the flow of the correction gas in this embodiment when the target component in the diluted correction gas is captured into the capture tube.

[0019] Figure 3 This is a diagram illustrating the flow of the calibration gas when the target component in the undiluted calibration gas is captured into the capture tube in this embodiment.

[0020] Figure 4 This is a diagram illustrating the flow of the correction gas when the target component in the sample gas is captured into the capture tube in this embodiment.

[0021] Figure 5 This is a diagram illustrating the gas flow during the measurement of the target component captured in the capture tube in this embodiment.

[0022] Figure 6 This is a flowchart illustrating an example of the calibration gas generation operation of the calibration gas supply unit in this embodiment.

[0023] Figure 7 This is a flowchart illustrating an example of the operation of calculating the flow rate (predetermined flow rate) of the source gas when the supply pressure of the source gas cylinder of the calibration gas supply unit is set to a specified pressure.

[0024] Figure 8 This is a flowchart illustrating other examples of actions for calculating a given flow rate.

[0025] Figure 9 This is a flow path configuration diagram illustrating a modified example of the flow path configuration of the calibration gas supply section of a gas analysis system. Detailed Implementation

[0026] Hereinafter, an embodiment of the gas analysis system and calibration gas supply method of the present invention will be described with reference to the accompanying drawings.

[0027] like Figure 1 As shown, the gas analysis system 1 includes a measuring unit 2, a calibration gas supply unit 4, a control unit 76, and a flow storage unit 78. In this embodiment, the measuring unit 2 is a gas chromatograph, and the component being measured is, for example, BTX contained in the atmosphere.

[0028] The measuring unit 2 includes a branch section 10, a multi-way valve 12, a collection tube 14, a first separation column 16, a second separation column 18, a detector 20, and a suction pump 22.

[0029] The branch section 10 is connected to a sample gas flow path 6, a calibration gas flow path 8, an inlet flow path 24, and an outlet flow path 40. The sample gas flow path 6 supplies sample gas to the measuring unit 2. The calibration gas flow path 8 supplies calibration gas from the calibration gas supply unit 4 to the measuring unit 2. The inlet flow path 24 allows the sample gas supplied through the sample gas flow path 6 or the calibration gas supplied through the calibration gas flow path 8 to flow, and is connected to one port a of the multi-way valve 12. The outlet flow path 40 discharges a portion of the calibration gas supplied from the calibration gas supply unit 4 to the outside. A shut-off valve 42 is provided on the outlet flow path 40. The branch section 10 can be a connector that connects multiple pipelines, or a switching mechanism such as a multi-way valve.

[0030] The trapping tube 14, used to trap the target components contained in the sample gas and calibration gas introduced through the inlet flow path 24, is installed on the trapping flow path 26. One end of the trapping flow path 26 is connected to port j of the multi-way valve 12, adjacent to port a connected to the inlet flow path 24, and the other end of the trapping flow path 26 is connected to port c of the multi-way valve 12, adjacent to port b connected to the suction flow path 32. A suction pump 22 is installed on the suction flow path 32. Port a of the multi-way valve 12 connected to the inlet flow path 24 and port b connected to the suction flow path 32 are adjacent to each other.

[0031] The first separation column 16 and the second separation column 18 are used to separate the target components in the sample gas and the calibration gas, respectively. The first separation column 16 is disposed on the first separation flow path 28, and the second separation column 18 is disposed on the second separation flow path 30. One end of the first separation flow path 28 is connected to port i of the multi-way valve 12, and the other end of the first separation flow path 28 is connected to port e of the multi-way valve 12.

[0032] In the multi-way valve 12, port i, connected to one end of the first separation flow path 28, is located between port j, connected to one end of the trapping flow path 26, and port h, connected to the drain flow path 38. Port e, connected to the other end of the first separation flow path 28, is located between port d, connected to the first carrier gas flow path 34, and port f, connected to the upstream end of the second separation flow path 30. In the multi-way valve 12, port g, located between port f, connected to the upstream end of the second separation flow path 30, and port h, connected to the drain flow path 38, is connected to the second carrier gas flow path 36. The downstream end of the second separation flow path 30 leads to the detector 20. The first carrier gas flow path 34 and the second carrier gas flow path 36 are flow paths for supplying carrier gas (e.g., nitrogen).

[0033] Multi-way valve 12 is a two-position valve that can be switched to the first state, which connects ports aj, bc, de, fg, and hi. Figure 1The first state) and the second state that connects ports ab, cd, ef, gh, and ij. Figure 4 Any state in the state of ( ).

[0034] Detector 20 outputs a signal corresponding to the concentration of the target component eluted from the first separation column 16 and the second separation column 18. The type of detector 20 is not particularly limited, but in addition to FID (Flame Ionization Detector), TCD (Thermal Conductivity Detector) and the like can also be used as detector 20.

[0035] The calibration gas supply unit 4 is configured to supply the measuring unit 2 with calibration gas containing the target component at a desired concentration. The calibration gas supply unit 4 is provided with a source gas cylinder 44 for supplying a source gas containing the target component at a known concentration, and a dilution gas cylinder 46 for supplying a dilution gas (e.g., nitrogen) for diluting the source gas.

[0036] A regulator 48 for adjusting the supply pressure is installed at the outlet of the source gas cylinder 44, and a source gas flow path 50 is connected downstream of the regulator 48. The source gas flow path 50 branches into a dilution flow path 52, a non-dilution flow path 54, and a purging flow path 64. A shut-off valve 56 and a resistance pipe 58 are installed on the dilution flow path 52, a shut-off valve 60 and a resistance pipe 62 are installed on the non-dilution flow path 54, and a shut-off valve 66 is installed on the purging flow path 64. The dilution flow path 52, the non-dilution flow path 54, and the purging flow path 64 are opened and closed by shut-off valves 56, 60, and 66, respectively. The dilution flow path 52 is used to prepare a calibration gas by diluting the source gas from the source gas cylinder 44 with a dilution gas, and the non-dilution flow path 54 is used to prepare a calibration gas without diluting the source gas from the source gas cylinder 44. The flow resistance of the resistance tube 62 installed in the undilution flow path 54 is smaller than that of the resistance tube 58 installed in the dilution flow path 52. Therefore, when the calibration gas is produced without diluting the source gas, the source gas can flow at a higher flow rate compared to the case where the calibration gas is produced by diluting the source gas.

[0037] A regulator 68 for adjusting the supply pressure is provided at the outlet of the dilution gas cylinder 46, and a dilution gas flow path 69 is connected downstream of the regulator 68. A pressure controller 70 and a resistance tube 72, which serve as flow regulation mechanisms, are provided on the dilution gas flow path 69. The flow rate of the dilution gas flowing through the dilution gas flow path 69 is controlled by the pressure controller 70. Alternatively, a flow controller such as a mass flow controller can be used instead of the pressure controller 70.

[0038] The dilution flow path 52, the non-dilution flow path 54, and the dilution gas flow path 69 merge in the confluence section 74 and are fluidly connected to the branch section 10.

[0039] In the calibration gas supply unit 4, by opening the shut-off valve 66 of the purging flow path 64 after the calibration gas supply is completed, the gas located in the flow path from the source gas cylinder 44 to the shut-off valves 56 and 60 can be purged to the outside. Furthermore, in Figure 1 In this configuration, a purging flow path 64 is provided as a branch of the undilution flow path 54, but it can perform the same function even if the purging flow path 64 is placed in another location. Figure 9 In the modified example shown, a purging flow path 64 is provided, branching off from the dilution flow path 52 at a position between the shut-off valve 56 and the resistance pipe 58. Since the flow resistance of the resistance pipe 58 is greater than that of the resistance pipe 62, even after the supply of source gas through the dilution flow path 52 ends and the shut-off valve 56 is closed, a high pressure remains between the shut-off valve 56 and the resistance pipe 58, potentially causing leakage of source gas to the branch 10 side. Figure 9 As in the example, if the purging flow path 64 is provided as a branch from the dilution flow path 52 at the position between the shut-off valve 56 and the resistance pipe 58, then after the supply of source gas through the dilution flow path 52 is completed, slightly opening the shut-off valve 66 can remove the residual pressure between the shut-off valve 56 and the resistance pipe 58. Furthermore, purging of the source gas flow path 50 can be performed by simultaneously opening both shut-off valves 56 and 66.

[0040] Here, in order to suppress the target components in the source gas adsorbed inside the resistance tubes 58 and 62 provided in the dilution flow path 52 and the non-dilution flow path 54, it is preferable to heat the resistance tubes 58 and 62 to a certain temperature (e.g., 80°C) using a heating element. In this embodiment, the measuring unit 2 is a gas chromatograph, which, since it is equipped with a column oven (not shown) for heating and controlling the first separation column 16 and the second separation column 18 to a constant temperature, can house the resistance tubes 58 and 62 together with the first separation column 16 and the second separation column 18 in the column oven for heating. That is, the column oven of the gas chromatograph 2 can be used as a heating element for heating the resistance tubes 58 and 62.

[0041] Next, use Figures 2-5 The procedures for measuring the target components in the calibration gas and sample gas are explained.

[0042] When the source gas diluted by the diluted gas is supplied from the calibration gas supply unit 4 to the measuring unit 2 as calibration gas, such as Figure 2As shown, source gas is supplied to the confluence section 74 via dilution flow path 52, and dilution gas is supplied to the confluence section 74 via dilution gas flow path 69. The source gas is diluted by the dilution gas in the confluence section 74 to become calibration gas, which is then supplied to the measuring section 2 via calibration gas flow path 8. In the measuring section 2, the multi-way valve 12 is set to a first state where the inlet flow path 24, the trapping flow path 26, and the suction flow path 32 are connected in series. At this time, the suction pump 22 is activated to introduce only a predetermined flow rate of calibration gas supplied to the branch section 10 into the trapping flow path 26, trapping the target component in the calibration gas into the trapping pipe 14. The portion of the calibration gas supplied to the branch section 10 that is not introduced into the trapping flow path 26 is discharged to the outside via the outlet flow path 40. Furthermore, the adjustment of the target component concentration of the calibration gas in the calibration gas supply section 4 will be described later.

[0043] When the source gas is supplied to the measuring unit 2 from the calibration gas supply unit 4 without dilution, such as Figure 3 As shown, only the source gas is supplied to the measuring unit 2 via the undilution flow path 54 and the calibration gas flow path 8. In the measuring unit 2, the multi-way valve 12 is set to a first state where the inlet flow path 24, the trapping flow path 26, and the suction flow path 32 are connected in series. At this time, the suction pump 22 is activated to introduce only a predetermined flow rate of the calibration gas supplied to the branch section 10 into the trapping flow path 26, trapping the target component in the calibration gas into the trapping pipe 14. The portion of the calibration gas supplied to the branch section 10 that is not introduced into the trapping flow path 26 is discharged to the outside through the discharge flow path 40.

[0044] Furthermore, when introducing sample gas into the measuring unit 2, such as Figure 4 As shown, the multi-way valve 12 is set to its first state, connecting the inlet flow path 24, the trapping flow path 26, and the suction flow path 32 in series. At this time, the suction pump 22 is activated to introduce the sample gas into the trapping flow path 26 at a specified flow rate, trapping the target component in the sample gas into the trapping tube 14.

[0045] like Figure 5 As shown, through Figures 2-4 The measurement of the target component in the calibration gas or sample gas captured in the capture tube 14 is performed as follows: the multi-way valve 12 is set to a second state, connecting the first carrier gas flow path 34, the capture flow path 26, the first separation flow path 28, and the second separation flow path 30 in series, and carrier gas is supplied from the first carrier gas flow path 34. The target component captured in the capture tube 14 is conveyed to the first separation column 16 and the second separation column 18 by the carrier gas supplied from the first carrier gas flow path 34. In the first separation column 16 and the second separation column 18, each component is separated and eluted over time and introduced into the detector 20 to obtain a signal based on its respective concentration.

[0046] Next, besides Figure 1Also used Figure 6 The flowchart explains the adjustment of the target component concentration of the calibration gas in the calibration gas supply unit 4.

[0047] When supplying calibration gas from the calibration gas supply unit 4 to the measuring unit 2, the control unit 76 sets the target concentration of the target component in the calibration gas (step 101). The regulator 48, located at the outlet of the source gas cylinder 44, is adjusted to bring the supply pressure of the source gas to a predetermined pressure (step 102). The adjustment of the regulator 48 can be performed automatically by the control unit 76 or manually by the user. The supply flow rate of the source gas when the supply pressure of the source gas cylinder 44 is adjusted to the predetermined pressure is stored as a predetermined flow rate in the flow rate storage unit 78. The predetermined flow rate stored in the flow rate storage unit 78 is calculated through a pre-executed flow rate calculation operation. The flow rate calculation operation will be described later.

[0048] The control unit 76 calculates the necessary flow rate of the dilution gas (step 103) to ensure that the flow rate of the source gas supplied from the source gas cylinder 44 to the merging unit 74 is a predetermined flow rate stored in the flow rate storage unit 78. Then, the control unit 76 controls the flow rate of the dilution gas supplied to the merging unit 74 to the necessary flow rate calculated by the pressure controller 70.

[0049] As described above, while maintaining the supply pressure and supply flow rate from the source gas cylinder 44 at a constant level, the control unit 76 controls only the flow rate of the dilution gas through the pressure controller 70, thereby controlling the target component concentration of the calibration gas supplied from the calibration gas supply unit 4 to the measuring unit 2 to the target concentration.

[0050] Here, for an example of the predetermined flow calculation operation, which calculates the flow rate (determined flow rate V0) of the source gas when the supply pressure of the source gas cylinder 44 is adjusted to a specified pressure by the regulator 48, in addition to Figure 1 Also used Figure 7 The flowchart is used for illustration.

[0051] The control unit 76 is configured to execute a predetermined flow calculation mode for calculating a predetermined flow rate, and performs the following actions when executing the predetermined flow calculation mode.

[0052] (Source Gas Measurement)

[0053] The supply pressure of the source gas cylinder 44 is adjusted to a specified pressure by the regulator 48. The control unit 76 sets the supply flow rate of the dilution gas from the dilution gas cylinder 46 to zero, so that the undiluted source gas flows in the collection flow path 26 at a specified flow rate for a certain period of time to collect the target component in the source gas into the collection tube 14. Then, the collected target component is introduced into the detector 20 by the carrier gas, and the measurement value A0 is obtained by the detector 20 (step 201).

[0054] (First calibration gas measurement)

[0055] With the supply pressure of the source gas cylinder 44 adjusted to a specified pressure, the control unit 76 controls the supply flow rate of the dilution gas to V1 via the flow controller 70, generating a first calibration gas with a first target component concentration. Then, the control unit 76 causes the generated first calibration gas to flow at a specified flow rate for a certain period of time in the trapping flow path 26 to trap the target component in the first calibration gas into the trapping tube 14. The trapped target component is then introduced into the detector 20 via a carrier gas, and the detector 20 acquires the measurement value A1 (step 202).

[0056] The control unit 76 calculates the flow rate V0 (predetermined flow rate) of the source gas when the supply pressure of the source gas cylinder 44 is adjusted to the specified pressure by substituting the supply flow rate V1 of the dilution gas in the first calibration gas measurement, the measured values ​​A0 and A1 of the source gas measurement and the first calibration gas measurement into the following formula (1) (step 203).

[0057] V0=V1(A1 / (A0-A1)) (1)

[0058] The control unit 76 stores the value of the predetermined flow rate V0 calculated using the above formula (1) in the flow rate storage unit 78.

[0059] Here, the above equation (1) is derived from the following equation (2), which is theoretically valid between the measured values ​​A0, A1, the given flow rate V0, and the supply flow rate V1.

[0060] A1=A0·(V0 / (V0+V1)) (2)

[0061] Figure 8 This is a flowchart representing other examples of a given flow calculation action.

[0062] In the predetermined flow rate calculation operation in this example, the second calibration gas measurement, which will be described later, is performed instead of the source gas measurement. That is, the first calibration gas measurement (step 301) described above and the second calibration gas measurement (step 302) described later are performed, and the predetermined flow rate V0 is calculated using the measurement values ​​obtained through these measurements (step 303).

[0063] (Second calibration gas measurement)

[0064] After the first calibration gas measurement (step 301) is completed, the control unit 76, with the supply pressure of the source gas cylinder 44 adjusted to a specified pressure, controls the supply flow rate of the dilution gas to V2 via the pressure controller 70 to generate a second calibration gas with the concentration of the second target component. Then, the control unit 76 causes the generated second calibration gas to flow at a specified flow rate for a certain period of time in the trapping flow path 26, trapping the target component in the second calibration gas into the trapping tube 14, and then introduces the trapped target component into the detector 20 via a carrier gas, and obtains the measurement value A2 through the detector 20 (step 302).

[0065] The control unit 76 calculates the flow rate V0 (predetermined flow rate) of the source gas when the supply pressure of the source gas cylinder 44 is adjusted to the specified pressure by substituting the supply flow rates V1 and V2 of the dilution gas in the first calibration gas measurement and the second calibration gas measurement and the measured values ​​A1 and A2 of each measurement into the following formula (3) (step 303).

[0066] V0=(A1V1-A2V2) / (A2-A1) (3)

[0067] The control unit 76 stores the value of the predetermined flow rate V0 calculated using the above formula (3) in the flow rate storage unit 78.

[0068] Here, equation (3) above is derived as follows.

[0069] If the measured value obtained by supplying only source gas to the measuring unit 2 is set as A0, then the measured value A1 obtained by the first calibration gas measurement can be expressed by the following formula (2) using A0, predetermined flow rate V0, and supply flow rate V1.

[0070] A1=A0·(V0 / (V0+V1)) (4)

[0071] Equation (4) is the same as equation (2) above.

[0072] Similarly, the measured value A2 obtained from the second calibration gas measurement described above can be expressed using A0, the predetermined flow rate V0, and the supply flow rate V2 in the following equation (5).

[0073] A2=A0·(V0 / (V0+V2)) (5)

[0074] If V0 is rearranged by eliminating A0 from equations (4) and (5) above, it becomes equation (3) above. That is, the flow rate V0 of the source gas when the supply pressure of the source gas cylinder 44 is adjusted to the specified pressure can be calculated by using the supply flow rates V1 and V2 of the dilution gas and the measured values ​​A1 and A2 in the first calibration gas measurement and the second calibration gas measurement.

[0075] The embodiments described above are merely examples of implementations of the gas analysis system and calibration gas supply method of the present invention. Implementations of the gas analysis system and calibration gas supply method of the present invention are shown below.

[0076] In one embodiment of the gas analysis system of the present invention, it comprises:

[0077] The measuring section is used to measure the concentration of the target component in the gas;

[0078] A calibration gas supply unit is used to supply the measuring unit with calibration gas used for correcting the measured values ​​of the measuring unit.

[0079] The control unit controls the operation of the measuring unit and the calibration gas supply unit.

[0080] The calibration gas supply unit includes:

[0081] A source gas cylinder is supplied with a source gas containing the target component at a known concentration;

[0082] A dilution gas cylinder supplies dilution gas for diluting the source gas;

[0083] The confluence section allows the source gas supplied from the source gas cylinder and the dilution gas supplied from the dilution gas cylinder to be combined to generate the correction gas;

[0084] A regulator is disposed between the source gas cylinder and the confluence section for adjusting the supply pressure of the source gas supplied from the source gas cylinder to the confluence section;

[0085] A flow regulating mechanism, disposed between the dilution gas cylinder and the confluence section, is used to control the flow rate of the dilution gas supplied from the dilution gas cylinder to the confluence section.

[0086] The supply flow rate of the source gas from the source gas cylinder is regulated solely by the regulator.

[0087] The control unit is configured such that, when supplying the calibration gas from the calibration gas supply unit to the measuring unit, while the supply pressure of the source gas is fixed at a predetermined pressure independent of the target concentration of the target component in the calibration gas by the regulator, the concentration of the target component in the calibration gas is adjusted to the target concentration solely by the flow regulating mechanism based on the supply pressure of the source gas, which is fixed at the predetermined pressure.

[0088] The gas analysis device is configured to extract only the flow rate required for analysis from the calibration gas that has been adjusted to the target concentration in the confluence section, and use it in the measurement section.

[0089] In a first embodiment of the gas analysis system of the present invention, a flow rate storage unit is further included, which stores the supply flow rate of the source gas from the source gas cylinder to the merging unit as a predetermined flow rate V0 when the supply pressure of the source gas is the predetermined pressure.

[0090] The control unit is configured to, when supplying the calibration gas from the calibration gas supply unit to the measuring unit, calculate, based on the predetermined flow rate V0 stored in the flow storage unit, the required supply flow rate of the dilution gas to achieve the target concentration of the target component in the calibration gas, and supply the dilution gas at the calculated flow rate through the flow regulating mechanism.

[0091] In a second embodiment of the gas analysis system of the present invention, when the control unit executes a predetermined flow rate calculation mode for determining the predetermined flow rate V0, it is configured to perform the following steps:

[0092] In the source gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is 0, and the measurement value A0 of the measuring unit is obtained when the source gas is supplied to the measuring unit at the specified flow rate.

[0093] In the first calibration gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to the first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate.

[0094] The calculation step, after the source gas measurement step and the first calibration gas measurement step are completed, uses...

[0095] V0 = V1(A1 / (A0-A1))

[0096] Calculate the given flow rate V0.

[0097] The flow storage unit is configured to store the predetermined flow V0 calculated in the calculation step. Furthermore, this second approach can be combined with the first approach described above.

[0098] In a third embodiment of the gas analysis system of the present invention, when the control unit executes a predetermined flow rate calculation mode for determining the predetermined flow rate V0, it is configured to perform the following steps:

[0099] In the first calibration gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to the first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate.

[0100] In the second calibration gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a second flow rate V2 to generate a second calibration gas, and the measurement value A2 of the measuring unit is obtained when the second calibration gas is supplied to the measuring unit at the specified flow rate.

[0101] The calculation steps, after the completion of the first calibration gas measurement step and the second calibration gas measurement step, use...

[0102] V0 = (A1V1 - A2V2) / (A2 - A1)

[0103] Calculate the given flow rate V0.

[0104] The flow storage unit is configured to store the predetermined flow V0 calculated in the calculation step.

[0105] In addition, the third option can be combined with the first option mentioned above.

[0106] In a fourth embodiment of the gas analysis system of the present invention, the calibration gas supply unit includes a resistance tube disposed downstream of the regulator, and the gas analysis system includes a heating element for heating the resistance tube. This allows for the suppression of the adsorption of target components in the source gas within the resistance tube.

[0107] Furthermore, the third scheme can be combined with the first scheme and / or any of the second and third schemes mentioned above.

[0108] In the fourth embodiment described above, when the measuring unit is a gas chromatograph equipped with a separation column for separating the analyte component from other components in the gas, and a column oven for housing the separation column and controlling its temperature at a predetermined temperature, the resistance tube of the calibration gas supply unit can be housed within the column oven, which serves as the heating element. Therefore, the column oven constituting the gas chromatograph can function as a heating element for heating the resistance tube, eliminating the need for a new heating element.

[0109] In one embodiment of the calibration gas supply method of the present invention, a calibration gas is generated by merging a source gas containing a target component at a known concentration and a dilution gas for diluting the source gas in a merging section, and the calibration gas is supplied to a measuring section for measuring the concentration of the target component in the gas. The calibration gas supply method comprises the following steps in sequence:

[0110] In the source gas supply step, the source gas is supplied to the confluence section while the supply pressure of the source gas from the source gas cylinder supplying the source gas is fixed at a predetermined pressure only by a regulator.

[0111] The flow rate calculation step calculates the necessary flow rate of the diluent gas for making the concentration of the target component in the correction gas generated in the confluence section reach the target concentration, based on the supply pressure of the source gas from the source gas cylinder which is fixed at the specified pressure.

[0112] The flow control step involves controlling the supply flow rate of the diluent gas from the diluent gas cylinder via a flow regulating mechanism, so that the flow rate of the diluent gas supplied from the diluent gas cylinder to the confluence section becomes the necessary flow rate calculated in the flow calculation step.

[0113] The calibration gas extraction step involves extracting a specified flow rate of calibration gas from the confluence section, wherein the concentration of the target component is adjusted to the target concentration, for measurement in the measurement section.

[0114] In a first embodiment of the calibration gas supply method of the present invention, the method further comprises:

[0115] The predetermined flow rate calculation step involves determining the supply flow rate of the source gas to the confluence section when the supply pressure of the source gas from the source gas cylinder is the predetermined pressure, prior to the source gas supply step, as the predetermined flow rate V0.

[0116] The traffic storage step stores the predetermined traffic calculated in the predetermined traffic calculation step.

[0117] In the flow calculation step, the predetermined flow rate V0 is used to calculate the necessary flow rate.

[0118] In the first scheme described above, the predetermined flow rate calculation step can also include:

[0119] In the source gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is 0, and the measurement value A0 of the measuring unit is obtained when the source gas is supplied to the measuring unit at the specified flow rate.

[0120] In the first calibration gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate.

[0121] The calculation step, after the source gas measurement step and the first calibration gas measurement step are completed, uses...

[0122] V0 = V1(A1 / (A0-A1))

[0123] Calculate the given flow rate V0.

[0124] Furthermore, in the first scheme described above, the predetermined flow rate calculation step can also include:

[0125] In the first calibration gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate.

[0126] In the second calibration gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a second flow rate V2 to generate a second calibration gas, and the measurement value A2 of the measuring unit is obtained when the second calibration gas is supplied to the measuring unit at the specified flow rate.

[0127] The calculation steps, after the completion of the first calibration gas measurement step and the second calibration gas measurement step, use...

[0128] V0 = (A1V1 - A2V2) / (A2 - A1)

[0129] Calculate the given flow rate V0.

[0130] Explanation of reference numerals in the attached figures

[0131] 1 Gas Analysis System

[0132] 2 Measurement Department

[0133] 4. Calibration Gas Supply Section

[0134] 6 Sample Gas Flow Path

[0135] 8. Correcting the gas flow path

[0136] 10 branches

[0137] 12-way valve

[0138] 14 collection tubes

[0139] 16. First Separation Column

[0140] 18. Separation column 2

[0141] 20 detectors

[0142] 22 suction pump

[0143] 24 Import Flow Path

[0144] 26 capture flow paths

[0145] 28 First Separation Flow Path

[0146] 30 Second Separation Flow Path

[0147] 32 suction flow path

[0148] 34 First carrier gas flow path

[0149] 36 Second carrier gas flow path

[0150] 38 drain flow path

[0151] 40 discharge flow path

[0152] 42, 56, 60, 66 stop valves

[0153] 44 Source Gas Cylinders

[0154] 46 dilution gas cylinders

[0155] 48, 68 regulators

[0156] 50 source gas flow paths

[0157] 52 Dilution Flow Path

[0158] 54 Dilution-free flow path

[0159] 58, 62, 72 resistance tubes

[0160] 64 Purging Flow Path

[0161] 69 Dilution Gas Flow Path

[0162] 70 Pressure Controller

[0163] 74 Convergence Department

[0164] 76 Control Department

[0165] 78. Traffic storage unit.

Claims

1. A gas analysis device, characterized in that, have: The measuring section is used to measure the concentration of the target component in the gas; A calibration gas supply unit is used to supply the measuring unit with calibration gas used for correcting the measured values ​​of the measuring unit. The control unit controls the operation of the measuring unit and the calibration gas supply unit. The calibration gas supply unit includes: A source gas cylinder is supplied with a source gas containing the target component at a known concentration; A dilution gas cylinder supplies dilution gas for diluting the source gas; The confluence section allows the source gas supplied from the source gas cylinder and the dilution gas supplied from the dilution gas cylinder to be combined to generate the correction gas; A regulator is disposed between the source gas cylinder and the confluence section for adjusting the supply pressure of the source gas supplied from the source gas cylinder to the confluence section; A flow regulating mechanism, disposed between the dilution gas cylinder and the confluence section, is used to control the flow rate of the dilution gas supplied from the dilution gas cylinder to the confluence section. The supply flow rate of the source gas from the source gas cylinder is regulated solely by the regulator. The control unit is configured such that, when supplying the calibration gas from the calibration gas supply unit to the measuring unit, while the supply pressure of the source gas is fixed at a predetermined pressure independent of the target concentration of the target component in the calibration gas by the regulator, the concentration of the target component in the calibration gas is adjusted to the target concentration solely by the flow regulating mechanism based on the supply pressure of the source gas, which is fixed at the predetermined pressure. The gas analysis device is configured to extract only the flow rate required for analysis from the calibration gas that has been adjusted to the target concentration in the confluence section, and use it in the measurement section.

2. The gas analysis apparatus as described in claim 1, characterized in that, It also includes a flow storage unit, which stores the supply flow rate of the source gas from the source gas cylinder to the confluence unit when the supply pressure is the predetermined pressure as a predetermined flow rate V0. The control unit is configured to, when supplying the calibration gas from the calibration gas supply unit to the measuring unit, calculate, based on the predetermined flow rate V0 stored in the flow storage unit, the required supply flow rate of the dilution gas to achieve the target concentration of the target component in the calibration gas, and supply the dilution gas at the calculated flow rate through the flow regulating mechanism.

3. The gas analysis apparatus as described in claim 2, characterized in that, When the control unit executes the predetermined flow calculation mode for determining the predetermined flow rate V0, it is configured to perform the following steps: In the source gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is 0, and the measurement value A0 of the measuring unit is obtained when the source gas is supplied to the measuring unit at the specified flow rate. In the first calibration gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to the first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate. The calculation step, after the source gas measurement step and the first calibration gas measurement step are completed, uses... V0 = V1(A1 / (A0-A1)) Calculate the given flow rate V0. The flow storage unit is configured to store the predetermined flow V0 calculated in the calculation step.

4. The gas analysis apparatus as described in claim 2, characterized in that, When the control unit executes the predetermined flow calculation mode for determining the predetermined flow rate V0, it is configured to perform the following steps: In the first calibration gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to the first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate. In the second calibration gas measurement step, under the condition that the supply pressure of the source gas is fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a second flow rate V2 to generate a second calibration gas, and the measurement value A2 of the measuring unit is obtained when the second calibration gas is supplied to the measuring unit at the specified flow rate. The calculation steps, after the completion of the first calibration gas measurement step and the second calibration gas measurement step, use... V0=(A1V1-A2V2) / (A2-A1) Calculate the given flow rate V0. The flow storage unit is configured to store the predetermined flow V0 calculated in the calculation step.

5. The gas analysis apparatus according to any one of claims 1 to 4, characterized in that, The calibration gas supply unit includes a resistance tube disposed downstream of the regulator. The gas analysis device includes a heating element for heating the resistance tube.

6. The gas analysis apparatus as described in claim 5, characterized in that, The measuring unit is a gas chromatograph equipped with a separation column for separating the analyte component in the gas from other components, and a column oven for housing the separation column and controlling the temperature of the separation column at a specified temperature. The resistance tube of the calibration gas supply unit is housed within the column oven, which serves as the heating element.

7. A method for supplying a calibration gas, comprising merging a source gas containing a target component at a known concentration and a dilution gas for diluting the source gas in a merging section to generate a calibration gas, and supplying the calibration gas to a measuring section for measuring the concentration of the target component in the gas, characterized in that, The following steps are performed in sequence: In the source gas supply step, the source gas is supplied to the confluence section while the supply pressure of the source gas from the source gas cylinder supplying the source gas is fixed at a predetermined pressure only by a regulator. The flow rate calculation step calculates the necessary flow rate of the diluent gas for making the concentration of the target component in the correction gas generated in the confluence section reach the target concentration, based on the supply pressure of the source gas from the source gas cylinder which is fixed at the specified pressure. The flow control step involves controlling the supply flow rate of the diluent gas from the diluent gas cylinder via a flow regulating mechanism, so that the flow rate of the diluent gas supplied from the diluent gas cylinder to the confluence section becomes the necessary flow rate calculated in the flow calculation step. The calibration gas extraction step involves extracting a specified flow rate of calibration gas from the confluence section, wherein the concentration of the target component is adjusted to the target concentration, for measurement in the measurement section.

8. The calibration gas supply method as described in claim 7, characterized in that, It also has: The predetermined flow rate calculation step involves determining the supply flow rate of the source gas to the confluence section when the supply pressure of the source gas from the source gas cylinder is the predetermined pressure, prior to the source gas supply step, as the predetermined flow rate V0. The traffic storage step stores the predetermined traffic V0 calculated in the predetermined traffic calculation step. In the flow calculation step, the predetermined flow rate V0 is used to calculate the necessary flow rate.

9. The calibration gas supply method as described in claim 8, characterized in that, The predetermined flow calculation steps include: In the source gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is 0, and the measurement value A0 of the measuring unit is obtained when the source gas is supplied to the measuring unit at the specified flow rate. In the first calibration gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate. The calculation step, after the source gas measurement step and the first calibration gas measurement step are completed, uses... V0 = V1(A1 / (A0-A1)) Calculate the given flow rate V0.

10. The calibration gas supply method as described in claim 8, characterized in that, The predetermined flow calculation steps include: In the first calibration gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a first flow rate V1 to generate the first calibration gas, and the measurement value A1 of the measuring unit is obtained when the first calibration gas is supplied to the measuring unit at the specified flow rate. In the second calibration gas measurement step, with the supply pressure of the source gas fixed at the specified pressure, the supply flow rate of the dilution gas from the dilution gas cylinder to the confluence section is adjusted to a second flow rate V2 to generate a second calibration gas, and the measurement value A2 of the measuring unit is obtained when the second calibration gas is supplied to the measuring unit at the specified flow rate. The calculation steps, after the completion of the first calibration gas measurement step and the second calibration gas measurement step, use... V0=(A1V1-A2V2) / (A2-A1) Calculate the given flow rate V0.

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