Gas analysis device, gas analysis method, and program

Abstract

The present invention reduces the frequency of maintenance of a gas analysis device. A gas analysis device (100) comprises: a cell (1); a light source (3); a detection unit (5); and a control unit (7). The cell (1) has a sample gas (SG) introduced thereinto. The light source (3) emits measurement light (L1) onto the cell (1) at prescribed light-emitting intervals (T). The detection unit (5) detects light (L2) generated by causing the measurement light (L1) to enter the cell (1). The control unit (7) controls the gas analysis device (100). The control unit (7) changes the light-emitting interval (T) for the measurement light (L1) in accordance with the concentration of a gas to be analyzed which is included in the sample gas (SG).

Description

Gas analyzer, gas analysis method, and program

[0001] The present invention relates to a gas analyzer for analyzing a target gas contained in a sample gas, a gas analysis method for analyzing the target gas, and a program for causing a computer to execute the gas analysis method.

[0002] Conventionally, there has been known an apparatus for analyzing a target gas by irradiating a target gas contained in a sample gas with light and detecting light resulting from an interaction between the light and the target gas. For example, there has been known an apparatus for analyzing a target gas by utilizing the property of the target gas that the target gas absorbs infrared light (see, for example, Patent Document 1).

[0003] In the device of Patent Document 1, the blinking frequency of the infrared light irradiated onto the gas to be analyzed can be set arbitrarily, so that even if vibrations are applied to the detector part that detects the infrared light absorbed by the gas to be analyzed, the vibrations are less likely to affect the analysis value.

[0004] Japanese Patent Application Laid-Open No. 2007-240239

[0005] Another known method analyzes a target gas by detecting the fluorescence generated when the target gas is irradiated with ultraviolet light. This analytical method is called ultraviolet fluorescence. In ultraviolet fluorescence, the sample gas is irradiated with flashes of ultraviolet light (excitation light) at predetermined intervals, which causes the target gas to fluoresce. The detection signals of multiple fluorescence signals generated by the multiple flashes are averaged and used for analysis. Averaging the detection signals can improve the S / N ratio of the signal used for analysis.

[0006] On the other hand, when irradiating with a flash of ultraviolet light, for example, the light source may need to be replaced periodically, and depending on the nature of the gas being analyzed, optical components (e.g., reflecting mirrors) in the path of the ultraviolet light may become contaminated, requiring some maintenance.

[0007] An object of the present invention is to reduce the frequency of maintenance of a gas analyzer.

[0008] Below, several aspects will be described as means for solving the problems. These aspects can be combined as desired as necessary. A gas analyzer according to one aspect of the present invention is an apparatus for analyzing a target gas contained in a sample gas. The gas analyzer includes a cell, a light source, a detection unit, and a control unit. The sample gas is introduced into the cell. The light source irradiates the cell with measurement light at predetermined irradiation intervals. The detection unit detects light generated when the measurement light is incident on the cell. The control unit controls the gas analyzer.

[0009] In the gas analyzer, the control unit changes the measurement light irradiation interval depending on the concentration of the target gas contained in the sample gas. This prevents the measurement light irradiation interval from being unnecessarily short, i.e., the measurement light irradiation frequency from being unnecessarily high, when the detection unit obtains a signal with a large S / N ratio depending on the concentration of the target gas. As a result, the life of the light source can be extended and contamination of components of the gas analyzer by the measurement light can be prevented, thereby reducing the maintenance frequency of the gas analyzer.

[0010] In the gas analyzer, the control unit may increase the irradiation interval when the concentration of the target gas is high, thereby preventing the irradiation interval of the measurement light from being unnecessarily short when the concentration of the target gas is high and a signal with a large S / N ratio is obtained from the detection unit.

[0011] In the gas analyzer, the measurement light may be ultraviolet light. Even when the measurement light is ultraviolet light, the frequency of irradiation of the measurement light can be adjusted according to the concentration of the gas to be analyzed, thereby reducing the maintenance frequency of the gas analyzer.

[0012] In the gas analyzer, the light source may be a xenon lamp. By adjusting the frequency of irradiation of the measurement light according to the concentration of the gas to be analyzed, unnecessary irradiation of the measurement light from the xenon lamp as the light source is not required, thereby extending the life of the xenon lamp as the light source.

[0013] In the gas analyzer, the control unit may be capable of setting a measurement concentration range for the target gas. In this case, the control unit may change the irradiation interval according to the set measurement concentration range. This prevents the irradiation interval of the measurement light from being unnecessarily short when a signal with a large S / N ratio is obtained depending on the concentration of the target gas.

[0014] In the gas analyzer described above, the detector may be a photomultiplier tube. In this case, the controller may change the gain of the photomultiplier tube depending on the concentration of the target gas contained in the sample gas. This allows the gas analyzer to measure a wider range of target gas concentrations.

[0015] In the gas analyzer, the control unit may reduce the gain of the photomultiplier tube when the concentration of the target gas is high. This prevents the detection signal from saturating when the target gas concentration is high and the intensity of light generated in the cell is high. As a result, target gases with higher concentrations can be analyzed.

[0016] A gas analysis method according to another aspect of the present invention is a gas analysis method in a gas analyzer that analyzes a target gas contained in a sample gas. The gas analysis method includes the following steps: irradiating a cell containing the sample gas with measurement light at a predetermined irradiation interval; changing the irradiation interval of the measurement light according to the concentration of the target gas contained in the sample gas; and detecting light generated by irradiating the measurement light into the cell.

[0017] In the gas analysis method described above, the measurement light irradiation interval is changed depending on the concentration of the target gas contained in the sample gas. This prevents the measurement light irradiation interval from being unnecessarily short, i.e., the measurement light irradiation frequency from being unnecessarily high, when a signal with a large S / N ratio is obtained depending on the concentration of the target gas. As a result, the maintenance frequency of the gas analyzer can be reduced.

[0018] A program according to yet another aspect of the present invention is a program for causing a computer to execute the above gas analysis method.

[0019] The frequency of maintenance of the gas analyzer can be reduced.

[0020] The present invention relates to a gas analyzer, ...

[0021] 1. First Embodiment (1) Configuration of Gas Analyzer The configuration of a gas analyzer 100 will be described with reference to FIG. 1. FIG. 1 is a diagram showing the configuration of a gas analyzer. The gas analyzer 100 shown in FIG. 1 is a device that analyzes a target gas using an ultraviolet fluorescence method. The target gas may be, for example, sulfur oxides (e.g., sulfur dioxide (SO )). ２ )) as excitation light. Such an analysis target gas is contained, for example, in gas flowing in the atmosphere or a flue, or in gas generated in various combustion processes. The above gas containing the analysis target gas is called a sample gas SG. The gas analyzer 100 is, for example, a device for measuring the concentration of the analysis target gas contained in the sample gas SG. The gas analyzer 100 includes a cell 1, a light source 3, a detection unit 5, and a control unit 7.

[0022] The cell 1 has an internal space IS. The cell 1 is provided with an inlet IN and an outlet OUT. The inlet IN introduces a sample gas SG into the internal space IS. The inlet IN is connected to a predetermined location (e.g., a sampling probe) through which the sample gas SG flows. The outlet OUT exhausts the sample gas SG introduced into the internal space IS.

[0023] The outlet OUT may be connected to a device such as a pump that suctions the internal space IS. In this case, the suction force of the pump introduces the sample gas SG into the internal space IS of the cell 1. Even if the outlet OUT is not connected to a device that suctions the internal space IS, the sample gas SG can be introduced into the internal space IS by the pressure of the sample gas SG.

[0024] The cell 1 is, for example, a hollow member made of metal. In this case, openings are provided at a position where measurement light L1 (described later) enters the internal space IS, a position where measurement light L1 after passing through the internal space IS is extracted to the outside, and a position where light L2 generated in the internal space IS of the cell 1 is extracted, and these openings are covered with transparent members.

[0025] The light source 3 irradiates light toward the internal space IS of the cell 1. The light source 3 outputs a flash of ultraviolet light as a flash of light L. The light source 3 outputs the flash of light L at a predetermined irradiation interval T under the control of the control unit 7. The irradiation interval T is the time between two flashes of light L, as shown in FIG. 2. FIG. 2 is a diagram illustrating the definition of the irradiation interval. The light source 3 is, for example, a xenon lamp.

[0026] A first lens unit 9, a mirror unit 11, a second lens unit 13, and a reference light measurement unit 15 are provided on the optical path from the light source 3 to the cell 1. The first lens unit 9 focuses the flash light L output from the light source 3.

[0027] The mirror section 11 transmits components included in a predetermined wavelength range out of the components included in the flash light L, while reflecting other components. In other words, the mirror section 11 transmits only the components of the flash light L that are within the predetermined wavelength range toward the cell 1. The mirror section 11 is configured, for example, with a plurality of dichroic mirrors (for example, 4 to 8).

[0028] The mirror unit 11 transmits components of the flash light L within a wavelength range that can be used as excitation light for causing the gas to emit light. When the gas to be analyzed is sulfur dioxide, the mirror unit 11 transmits components of the flash light L having a wavelength around 200 nm toward the cell 1. In the following description, the light of the flash light L having a wavelength component that can be used as excitation light, i.e., the light that has passed through the mirror unit 11, is referred to as "measurement light L1."

[0029] The second lens portion 13 condenses the measurement light L1 that has passed through the mirror portion 11 , and causes the condensed measurement light L1 to enter the internal space IS of the cell 1 .

[0030] The reference light measurement unit 15 measures the intensity of the measurement light L1 after passing through the internal space IS of the cell 1, and outputs a measurement result signal corresponding to the measured intensity of the measurement light L1. The reference light measurement unit 15 is, for example, a photodiode.

[0031] When the sample gas SG is introduced into the internal space IS of the cell 1, the measurement light L1 excites the target gas contained in the sample gas SG in the internal space IS. The target gas excited by the measurement light L1 emits light and returns to its ground state. The gas analyzer 100 analyzes the target gas contained in the sample gas SG based on the emission intensity of the target gas.

[0032] The detector 5 detects light generated by the measurement light L1 entering the internal space IS of the cell 1, i.e., light L2 generated from the target gas. The detector 5 outputs a detection signal based on the intensity of the light L2 from the target gas. The detector 5 is, for example, a photomultiplier tube.

[0033] A third lens unit 17 and an optical filter unit 19 are provided on the optical path of light L2 from the cell 1 to the detection unit 5. The third lens unit 17 collects light L2 generated in the internal space IS of the cell 1. The optical filter unit 19 passes only components within a specific wavelength range of light L2 that has passed through the third lens unit 17, and attenuates other components.

[0034] The control unit 7 is a computer system configured with a CPU, storage devices (RAM, ROM, hard disk, SSD, etc.), various interfaces, and a display, and controls the gas analyzer 100 and analyzes the target gas. The control unit 7 has a calculation unit 71 and a display unit 73.

[0035] The calculation unit 71 is composed of the CPU of the control unit 7, a storage device, and an interface, and realizes processes related to the control of the gas analyzer 100 and processes related to the analysis of the target gas by executing programs stored in the storage device. Note that some of the functions may be realized by the calculation unit 71 as hardware.

[0036] The display unit 73 is a display of the control unit 7, and displays information related to the control of the gas analyzer 100, information related to the analysis of the target gas, analysis results of the target gas, etc. The display unit 73 is, for example, a liquid crystal display, an organic EL display, or the like.

[0037] The calculation unit 71 can change the measurement concentration range of the gas to be analyzed, for example, through a user operation. Specifically, multiple measurement concentration ranges selectable by the user are displayed on the display unit 73, and the user is allowed to select one of them through operation. The calculation unit 71 changes the control method for the light source 3 and / or the detection unit 5 depending on the selected measurement concentration range.

[0038] Specifically, the calculation unit 71 changes the irradiation interval T of the flash light L emitted from the light source 3 according to the selected measurement concentration range. More specifically, when a range for measuring a high concentration of the target gas is selected, the calculation unit 71 lengthens the irradiation interval T to reduce the number of outputs of the measurement light L1 (flash light L) per unit time. On the other hand, when a range for measuring a low concentration of the target gas is selected, the calculation unit 71 shortens the irradiation interval T to increase the number of outputs of the measurement light L1 per unit time.

[0039] Furthermore, the calculation unit 71 changes the gain of the detection unit 5, which is a photomultiplier tube, depending on the selected measurement concentration range. Specifically, when a range for measuring a high concentration of the target gas is selected, the gain is reduced so that the detection signal is not excessively amplified. On the other hand, when a range for measuring a low concentration of the target gas is selected, the gain is increased so that the detection signal is sufficiently amplified. The gain of the detection unit 5, which is a photomultiplier tube, can be adjusted, for example, by adjusting the voltage applied to the detection unit 5, which is a photomultiplier tube.

[0040] The calculation unit 71 analyzes the target gas based on the detection signal (i.e., the intensity of the light L2 from the target gas) acquired by the detection unit 5, and displays the analysis results on the display unit 73. In the gas analyzer 100, multiple measurement light beams L1 are irradiated per unit time, so the detection unit 5 outputs one detection signal corresponding to each measurement light beam L1. That is, the detection unit 5 outputs multiple detection signals per unit time. In addition, the reference light measurement unit 15 outputs one measurement result signal corresponding to each measurement light beam L1. That is, the reference light measurement unit 15 outputs multiple measurement result signals per unit time.

[0041] Therefore, the calculation unit 71 analyzes the target gas as follows: First, the calculation unit 71 calculates the moving average value of the plurality of detection signals acquired in the above unit time and the moving average value of the plurality of measurement result signals acquired in the corresponding unit time. Then, the calculation unit 71 calculates the ratio between the moving average value of the detection signal and the moving average value of the corresponding measurement result signal, and analyzes the target gas using this ratio.

[0042] In this way, by calculating the ratio between the moving average value of the detection signal and the moving average value of the measurement result signal, a signal value with a high S / N ratio can be obtained. By using this ratio between the moving average value of the detection signal and the moving average value of the measurement result signal in analysis, the target gas can be analyzed more accurately.

[0043] (2) Operation of the Gas Analyzer Hereinafter, the operation of analyzing the target gas in the gas analyzer 100 will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the operation of the gas analyzer.

[0044] First, the sample gas SG is introduced into the internal space IS of the cell 1. Then, the calculation unit 71 of the control unit 7 sets the measurement concentration range through a user operation (step S1). Next, the calculation unit 71 sets the irradiation interval of the flash light L (i.e., measurement light L1) output from the light source 3 according to the concentration of the target gas contained in the sample gas SG. The calculation unit 71 also sets the gain of the detection unit 5 according to the concentration of the target gas contained in the sample gas SG. Specifically, the following process is performed.

[0045] After setting the measurement concentration range, the calculation unit 71 determines whether the set measurement concentration range is suitable for analyzing a high concentration of the target gas (step S2). If the target gas concentration in the sample gas SG is likely to be high and a high concentration range is set as the measurement concentration range ("Yes" in step S2), the calculation unit 71 increases the irradiation interval T and reduces the number of flashes of light L (measurement light L1) output per unit time, as shown in FIG. 4 (step S3). The calculation unit 71 also reduces the gain of the detection unit 5 to prevent the detection signal from saturating (step S4). Figure 4 shows an example of the flash light output state when the irradiation interval is increased.

[0046] On the other hand, if the concentration of the target gas contained in the sample gas SG is likely to be low and the measurement concentration range is set to a low concentration range ("No" in step S2), the calculation unit 71 sets the irradiation interval T to a small value and increases the number of flashes of light L (measurement light L1) output per unit time, as shown in Figure 5 (step S5). The calculation unit 71 also increases the gain of the detection unit 5 so that the detection signal can be sufficiently amplified (step S6). Figure 5 is a diagram showing an example of the flash light output state when the irradiation interval is reduced.

[0047] Thereafter, the calculation unit 71 controls the light source 3 to generate the flash light L (measurement light L1) in accordance with the settings made by executing steps S2 to S6 (step S7), and also adjusts the gain of the detection unit 5 in accordance with the settings.

[0048] In step S7, the measurement light L1 is generated at the set irradiation interval T, and the control unit 7 acquires detection signals from the detection unit 5 at time intervals corresponding to the irradiation interval T of the measurement light L1 (step S8). Also, the control unit 7 acquires measurement result signals of the intensity of the measurement light L1 from the reference light measurement unit 15 at time intervals corresponding to the irradiation interval T of the measurement light L1.

[0049] The calculation unit 71 then analyzes the target gas based on the multiple detection signals and multiple measurement result signals acquired per unit time (step S9). Specifically, the calculation unit 71 first calculates a moving average value of the multiple detection signals and a moving average value of the multiple measurement result signals. The calculation unit 71 then calculates the ratio between the moving average value of the detection signals and the moving average value of the measurement result signals, and performs analysis of the target gas (e.g., calculation of the concentration of the target gas) based on this ratio. After analyzing the target gas, the analysis result of the target gas is displayed on the display unit 73.

[0050] Thereafter, it is determined whether or not to shut down the gas analyzer 100 (step S10). If the analysis is to be continued without shutting down the gas analyzer 100 ("No" in step S10), the operation of the gas analyzer 100 returns to step S1. That is, the gas analyzer 100 repeatedly executes steps S1 to S9 described above. On the other hand, if the gas analyzer 100 is to be shut down and the analysis is to be ended ("Yes" in step S10), the gas analyzer 100 shuts down.

[0051] By performing steps S1 to S9 described above, when analyzing a low-concentration target gas, a large amount of measurement light L1 can be generated per unit time, thereby obtaining a large number of detection signals and measurement result signals (signals related to the intensity of the measurement light L1). As a result, the gas analyzer 100 can accurately analyze a low-concentration target gas. This is because obtaining a large number of detection signals and measurement result signals allows the detection signals to be used to calculate a moving average value of the detection signals with a large S / N ratio, and the measurement result signals to be used to calculate a moving average value of the measurement result signals with a large S / N ratio. Furthermore, analyzing the target gas based on the ratio between the moving average value of the detection signals and the moving average value of the measurement result signals means analyzing the target gas using data (ratio) with an even larger S / N ratio. Furthermore, by increasing the gain of the detector 5, a detection signal large enough for gas analysis can be obtained, allowing for even more accurate analysis of a low-concentration target gas.

[0052] On the other hand, when analyzing a high concentration of target gas, reducing the gain of the detection unit 5 can prevent the detection signal from saturating. As a result, the high concentration of target gas can be accurately analyzed. This is because the detection signal does not saturate, resulting in a magnitude that corresponds to the concentration of the target gas. In other words, the detection signal does not become unchanging in accordance with the concentration of the target gas, or the detection signal does not change nonlinearly with respect to the concentration of the target gas. Furthermore, when analyzing a high concentration of target gas, reducing the number of outputs of the measurement light L1 per unit time does not reduce the analysis accuracy of the target gas. This is because, when the concentration of the target gas is high, detection signals and measurement result signals with a high S / N ratio can be obtained without calculating moving average values ​​of multiple detection signals and measurement result signals.

[0053] As a result, the gas analyzer 100 can accurately analyze a wide range of concentration of the target gas.

[0054] Furthermore, when analyzing a high-concentration target gas, by increasing the irradiation interval T, it is possible to prevent the irradiation interval of the measurement light L1 from being unnecessarily short when a detection signal with a high S / N ratio is obtained from the detection unit 5. In other words, it is possible to prevent the unnecessary output of a large amount of measurement light L1. As a result, it is possible to extend the life of the light source 3 and prevent the components of the gas analyzer 100 from being contaminated by the measurement light L1. Therefore, it is possible to reduce the frequency of maintenance of the gas analyzer 100.

[0055] 2. Features of the Embodiments The above-described embodiments can also be described as follows. (1) A gas analyzer (e.g., gas analyzer 100) is an apparatus for analyzing a target gas contained in a sample gas (e.g., sample gas SG). The gas analyzer includes a cell (e.g., cell 1), a light source (e.g., light source 3), a detector (e.g., detector 5), and a controller (e.g., controller 7). The sample gas is introduced into the cell. The light source irradiates the cell with measurement light (e.g., measurement light L1) at predetermined irradiation intervals (e.g., irradiation interval T). The detector detects light (e.g., light L2) generated by the measurement light entering the cell. The controller controls the gas analyzer.

[0056] In the gas analyzer, the control unit changes the measurement light irradiation interval depending on the concentration of the target gas contained in the sample gas. This prevents the measurement light irradiation interval from being unnecessarily short, i.e., the measurement light irradiation frequency from being unnecessarily high, when the detection unit obtains a signal with a large S / N ratio depending on the concentration of the target gas. As a result, the life of the light source can be extended and contamination of components of the gas analyzer by the measurement light can be prevented, thereby reducing the maintenance frequency of the gas analyzer.

[0057] (2) In the gas analyzer of (1), the control unit may increase the irradiation interval when the concentration of the target gas is high, thereby preventing the irradiation interval of the measurement light from being unnecessarily short when the concentration of the target gas is high and a signal with a large S / N ratio is obtained from the detection unit.

[0058] (3) In the gas analyzer of (1) or (2), the measurement light may be ultraviolet light. Even when the measurement light is ultraviolet light, the frequency of irradiation of the measurement light can be adjusted according to the concentration of the gas to be analyzed, thereby reducing the maintenance frequency of the gas analyzer.

[0059] (4) In the gas analyzer of (3), the light source may be a xenon lamp. By adjusting the frequency of irradiation of the measurement light according to the concentration of the gas to be analyzed, unnecessary irradiation of the measurement light from the xenon lamp as the light source is not required, thereby extending the life of the xenon lamp as the light source.

[0060] (5) In the gas analyzer according to any one of (1) to (4), the control unit may be capable of setting a measurement concentration range for the target gas. In this case, the control unit may change the irradiation interval according to the set measurement concentration range. This prevents the irradiation interval of the measurement light from being unnecessarily short when a signal with a large S / N ratio is obtained depending on the concentration of the target gas.

[0061] (6) In the gas analyzers described above in (1) to (5), the detector may be a photomultiplier tube. In this case, the controller may change the gain of the photomultiplier tube depending on the concentration of the target gas contained in the sample gas. This allows the gas analyzer to measure a wider range of target gas concentrations.

[0062] (7) In the gas analyzer of (6), the control unit may reduce the gain of the photomultiplier tube when the concentration of the target gas is high. This prevents the detection signal from saturating when the concentration of the target gas is high and the intensity of light generated in the cell is high. As a result, target gases with higher concentrations can be analyzed.

[0063] (8) A gas analysis method is a gas analysis method in a gas analyzer that analyzes a target gas contained in a sample gas. The gas analysis method includes the following steps: irradiating a cell containing sample gas with measurement light at predetermined irradiation intervals (e.g., steps S1 to S7); changing the irradiation interval of the measurement light according to the concentration of the target gas contained in the sample gas (e.g., steps S1 to S7); and detecting light generated by irradiating the measurement light into the cell (e.g., step S8).

[0064] In the gas analysis method described above, the measurement light irradiation interval is changed depending on the concentration of the target gas contained in the sample gas. This prevents the measurement light irradiation interval from being unnecessarily short, i.e., the measurement light irradiation frequency from being unnecessarily high, when a signal with a large S / N ratio is obtained depending on the concentration of the target gas. As a result, the maintenance frequency of the gas analyzer can be reduced.

[0065] 3. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described in this specification can be arbitrarily combined as needed. (A) The processing content of each step of the flowchart described using Figure 3 and / or the processing order of each step can be changed as appropriate without departing from the spirit of the invention.

[0066] (B) The irradiation interval T of the measurement light L1 and / or the gain of the detection unit 5 may be set not only according to the measurement concentration range but also according to the analysis result of the target gas (actual concentration of the target gas). For example, after the analysis result of the target gas is obtained, the control unit 7 may set the irradiation interval T of the measurement light L1 and / or the gain of the detection unit 5 according to the analysis result.

[0067] (C) The ratio between the detection signal and the measurement result signal used in the analysis of the target gas may be calculated by calculating multiple ratios between one detection signal and one corresponding measurement result signal, and calculating the moving average value of the multiple ratios.

[0068] The present invention can be widely applied to the analysis of target gases contained in sample gases.

[0069] 100: Gas analyzer 1: Cell IS: Internal space IN: Inlet OUT: Outlet 3: Light source 5: Detector 7: Control unit 71: Calculator 73: Display 9: First lens 11: Mirror 13: Second lens 15: Reference light measuring unit 17: Third lens 19: Optical filter L1: Measurement light SG: Sample gas T: Irradiation interval

Claims

1. A gas analyzer that analyzes the target gas contained in a sample gas, A cell into which the sample gas is introduced, A light source that irradiates the cell with measurement light at predetermined irradiation intervals, A detection unit for detecting light generated by injecting the aforementioned measurement light into the cell, A control unit that controls the gas analyzer, Equipped with, The control unit changes the irradiation interval according to the concentration of the analyte gas contained in the sample gas. Gas analyzer.

2. The gas analyzer according to claim 1, wherein the control unit increases the irradiation interval when the concentration of the gas to be analyzed is high.

3. The gas analyzer according to claim 1 or 2, wherein the measurement light is ultraviolet light.

4. The gas analyzer according to claim 3, wherein the light source is a xenon lamp.

5. The gas analyzer according to claim 1, wherein the control unit can set the measurement concentration range of the gas to be analyzed, and changes the irradiation interval according to the set measurement concentration range.

6. The detection unit is a photomultiplier tube, The gas analyzer according to claim 1, wherein the control unit changes the gain of the photomultiplier tube according to the concentration of the gas to be analyzed contained in the sample gas.

7. The gas analyzer according to claim 6, wherein the control unit reduces the gain of the photomultiplier tube when the concentration of the gas to be analyzed is high.

8. A gas analysis method in a gas analyzer that analyzes the target gas contained in a sample gas, The steps include: irradiating a cell into which the sample gas has been introduced with measurement light at predetermined irradiation intervals; The steps include changing the irradiation interval according to the concentration of the analyte gas contained in the sample gas, The steps include detecting light generated by injecting the measurement light into the cell, A gas analysis method comprising the following features.

9. A program for causing a computer to execute a gas analysis method in a gas analyzer that analyzes a target gas contained in a sample gas, wherein the gas analysis method is: The steps include: irradiating the cell into which the sample gas has been introduced with measurement light at predetermined irradiation intervals; The steps include changing the irradiation interval according to the concentration of the analyte gas contained in the sample gas, The steps include detecting light generated by injecting the measurement light into the cell, A program that includes the following features.