Detector and gas analyzer

Abstract

A detector and a gas analyzer are provided. In the detector, a first gas chamber (54) through which infrared light passes and a second gas chamber through which infrared light passes after passing through the first gas chamber (54) are provided. The first gas chamber (54) and the second gas chamber are filled with a gas. A flow sensor detects a flow rate of the gas flowing through a communication passage. A dry container (8) in which a drying agent is stored is housed in a housing chamber constituted by an insertion hole (50f) and a sealing member (59). The housing chamber is connected to the first gas chamber (54) through a first passage (50d).

Description

TECHNICAL FIELD

[0001] The present application relates to a detector that detects intensity of infrared light, and a gas analyzer that has the detector. BACKGROUND

[0002] In the past, a non-dispersive infrared absorption method has been used in order to perform component analysis of a gas. As a device that performs component analysis of a gas, a gas analyzer that uses a detector that detects intensity of infrared light is known. As one of the detectors used in the gas analyzer, a detector that encloses a gas containing a specific gas component can be cited. The specific gas component is a component that absorbs a specific wavelength component of infrared light. In the gas analyzer that uses the detector that encloses the gas, a light source that emits infrared light, a cell in which a gas to be analyzed flows, and the detector are arranged. The infrared light emitted from the light source transmits through the cell. The infrared light after transmitting through the cell is incident on the detector.

[0003] The gas to be analyzed contains the specific gas component that absorbs the specific wavelength component of infrared light. The more the amount of the specific gas component contained in the gas to be analyzed, that is, the higher the concentration of the specific gas component contained in the gas to be analyzed, the more the amount of the infrared light absorbed in the cell, and thus the weaker the intensity of the specific wavelength component of the infrared light incident on the detector.

[0004] In the detector, a first gas chamber and a second gas chamber are filled with a gas containing the specific gas component. The first gas chamber and the second gas chamber are connected by a communication passage. The infrared light incident on the detector transmits through the first gas chamber and the second gas chamber in this order. In the first gas chamber, the specific gas component absorbs the specific wavelength component of the infrared light. The specific wavelength component of the infrared light after transmitting through the first gas chamber is absorbed by the specific gas component of the gas contained in the second gas chamber. In the case where the infrared light is absorbed, the gases contained in the first gas chamber and the second gas chamber expand. The more the amount of the infrared light absorbed, the more the gases expand.

[0005] With respect to the infrared light that enters the detector, most of the specific wavelength component is absorbed by the gas that fills the first gas chamber, and the amount of the infrared light absorbed by the gas that fills the second gas chamber is small. Therefore, in the case where the infrared light is incident on the detector, the gas flows from the first gas chamber to the second gas chamber through the communication passage. In the detector, the flow rate of the gas that flows through the communication passage is detected. The stronger the intensity of the specific wavelength component of the infrared light incident on the detector, the greater the difference in the amount of the infrared light absorbed by the gases in the first gas chamber and the second gas chamber. The greater the difference in the amount of the infrared light absorbed by the gases in the first gas chamber and the second gas chamber, the more the flow rate of the gas that flows through the communication passage. Therefore, the detection of the flow rate of the gas corresponds to the detection of the intensity of the specific wavelength component of the infrared light.

[0006] The more the amount of the specific gas component contained in the gas to be analyzed, that is, the higher the concentration of the specific gas component contained in the gas to be analyzed, the weaker the intensity of the infrared light incident on the detector, and the smaller the flow rate of the gas flowing through the communication passage. The concentration of the specific gas component is calculated from the flow rate of the gas detected by the detector. An example of such a gas analyzer is disclosed in Patent Document 1.

[0007] Patent Document 1: Japanese Patent Publication No. 2002-131230 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] There is a case where the wavelength region of the infrared light absorbed by the specific gas component overlaps with the wavelength region of the infrared light absorbed by moisture. In this case, when moisture is contained in the detector, the flow rate of the gas detected by the detector is different from the flow rate corresponding to the concentration of the specific gas component contained in the gas to be analyzed. Therefore, in the case where moisture is contained in the detector, that is, in the case where the detector is not dried, the concentration of the specific gas component cannot be accurately measured.

[0010] The present application has been achieved in view of the above-described circumstances, and aims to provide a detector in which a first gas chamber and a second gas chamber are dried, and a gas analyzer provided with the detector.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] The detector of one embodiment of the present application detects the intensity of infrared light, and includes a first gas chamber filled with a gas containing an acidic gas component, through which infrared light is transmitted; a second gas chamber filled with a gas containing the gas component, through which infrared light transmitted through the first gas chamber is transmitted; a communication passage that communicates the first gas chamber and the second gas chamber; a flow rate sensor that detects the flow rate of the gas flowing through the communication passage; and a housing chamber connected to the first gas chamber or the second gas chamber through a passage, which houses a drying container into which an acidic desiccant is put.

[0013] According to the above-described embodiment, the gas contained in the first gas chamber and the second gas chamber enters the drying container, and the moisture contained in the gas is absorbed by the desiccant. Thus, the first gas chamber and the second gas chamber are dried. Further, the acidic gas component is contained in the gas, and an acidic substance is used as the desiccant. Thus, a neutralization reaction between the gas component and the desiccant does not occur, and the gas contained in the first gas chamber and the second gas chamber is properly dried.

[0014] In the detector of one embodiment of the present application, the gas component is nitric oxide, and the desiccant is phosphorus pentoxide, calcium chloride, or magnesium sulfate.

[0015] According to the above-described manner, the first gas chamber and the second gas chamber contain the gas containing nitric oxide, and phosphorus pentoxide, calcium chloride, or magnesium sulfate is used as the drying agent.

[0016] In the detector of one embodiment, the drying container is provided with a gas inlet and outlet at a position different from a position opposite to the passage port of the passage provided in the housing chamber, and the inlet and outlet communicate with the passage.

[0017] According to the above-described manner, in the case where the drying agent is housed in the housing chamber, when the drying agent has deliquescent property, the drying agent absorbs moisture, and part of the drying agent changes to a liquid state. When the gas is sealed into the detector after the inside of the detector is made vacuum in the state where the drying agent is housed in the housing chamber of the detector, in the case where the drying agent deliquesces in the process of making the inside of the detector vacuum, there is a possibility that the liquid after deliquescence scatters. In the case where the liquid scatters, the liquid after deliquescence adheres to the infrared light-transmitting window or the like provided in the first gas chamber or the second gas chamber, and as a result, there is a possibility that fogging occurs. In the case where the infrared light transmits through the fogged transmitting window, the intensity of the infrared light attenuates.

[0018] In this case, the flow rate of the gas detected by the flow rate sensor cannot accurately indicate the intensity of the specific wavelength component of the infrared light incident on the first gas chamber. However, in the drying container, the gas inlet and outlet are provided at a position different from a position opposite to the passage port. Thus, even in the case where the liquid scatters, the scattered liquid is less likely to enter the first gas chamber or the second gas chamber, and the possibility of fogging in the transmitting window is low.

[0019] The detector of one embodiment of the present application detects the intensity of infrared light, and includes a first gas chamber filled with a gas through which infrared light is transmitted; a second gas chamber filled with a gas through which the infrared light transmitted through the first gas chamber is transmitted; a communication passage that communicates the first gas chamber and the second gas chamber; a flow rate sensor that detects a flow rate of a gas flowing through the communication passage; and a housing chamber that is connected to the first gas chamber or the second gas chamber through a passage, and houses a drying container into which a drying agent is put, wherein the drying container is provided with a gas inlet and outlet at a position different from a position opposite to a passage port of the passage provided in the housing chamber, and the inlet and outlet communicate with the passage.

[0020] According to the above method, the gas filling the first and second gas chambers enters the drying container, where the moisture contained in the gas is absorbed by the desiccant. As a result, the first and second gas chambers remain dry. The drying container has a gas inlet and outlet located at a location different from the location opposite the passageway opening provided in the storage chamber. Therefore, as described above, even if liquid scatters, it is unlikely to enter the first or second gas chambers, reducing the likelihood of clouding the transmission window.

[0021] A gas analyzer according to one embodiment of the present invention is used to analyze the concentration of a specific gas component contained in the gas to be analyzed and absorbing a specific wavelength component of infrared light. The gas analyzer comprises: the above-mentioned detector; a light source that emits infrared light; and a pool through which the gas to be analyzed flows, the first gas chamber and the second gas chamber are filled with gas containing the specific gas component, the infrared light emitted by the light source passes through the pool, and the infrared light after passing through the pool passes through the first gas chamber of the detector, and the concentration is calculated based on the flow rate detected by the flow sensor.

[0022] According to the above method, the amount of infrared light absorbed by a specific gas component fluctuates depending on the concentration of the specific gas component contained in the gas to be analyzed flowing through the cell. Consequently, the intensity of the specific wavelength component of the infrared light after passing through the cell fluctuates. The flow rate of gas flowing through the detector's communication channel, or the gas flow rate detected by the flow sensor, fluctuates depending on the intensity of the specific wavelength component of the infrared light after passing through the cell. Therefore, the concentration is detected based on the flow rate detected by the flow sensor. Detecting the gas flow rate is equivalent to detecting the intensity of the specific wavelength component of the infrared light.

[0023] In a gas analyzer of one embodiment of the present invention, the number of the detectors is two, the infrared light after passing through the pool passes through the first gas chamber of one detector, and the infrared light after passing through the second gas chamber of one detector passes through the first gas chamber of the other detector, and the concentration is calculated based on the two flow rates detected by the two flow sensors of the two detectors.

[0024] According to the above method, when the gas to be analyzed contains, in addition to the specific gas component, an interfering gas component whose wavelength region of infrared light absorbed overlaps with the wavelength region of infrared light absorbed by the specific gas component, the attenuation of the infrared light generated when the infrared light passes through the cell represents the concentration of the specific gas component and the interfering gas component as a whole contained in the gas to be analyzed. For the infrared light after passing through one detector, the intensity of the specific wavelength component approaches zero. Therefore, the attenuation of the infrared light after passing through one detector represents the concentration of the interfering gas component, and the flow rate of the gas corresponding to this concentration is detected by the other detector. Therefore, based on the outputs of the two detectors, the concentration of the specific gas component contained in the gas to be analyzed can be accurately calculated.

[0025] In the gas analyzer of one embodiment of the present invention, the concentration of the specific gas component contained in the first gas chamber and the second gas chamber of the other detector is higher than the concentration of the specific gas component contained in the first gas chamber and the second gas chamber of the one detector.

[0026] According to the above embodiment, the intensity of infrared light transmitted through one detector is weak, but the concentration of the specific gas component contained in the first and second gas chambers of the other detector is high, so the gas flow rate can be easily detected.

[0027] In a gas analyzer of one embodiment of the present invention, the cell has a transmission window through which the infrared light emitted by the light source passes, and the light source has: a light-emitting element that emits infrared light; a reflector in the shape of a box with one surface open, which accommodates the light-emitting element and reflects the infrared light emitted by the light-emitting element; and an annular adhesion component that is in close contact with the peripheral edge of the opening of the reflector and the peripheral edge of the transmission window.

[0028] With this configuration, since there's no gap between the reflector and the transmissive window, wind doesn't enter the reflector, and the temperature of the light-emitting element doesn't fluctuate due to wind. Normally, the intensity of infrared light emitted by a light-emitting element fluctuates depending on its temperature. However, since the temperature of the light-emitting element doesn't fluctuate due to wind, the intensity of the infrared light emitted by the light source remains stable.

[0029] A gas analyzer according to one embodiment of the present invention includes a blower, wherein the light source includes a cylindrical cover covering a side surface of the reflector, the cover having a plurality of openings, and the blower blows air toward the cover.

[0030] According to the above configuration, when the reflector is constructed of a component with high thermal conductivity, such as metal, heat generated by the light-emitting element is conducted to the reflector, dissipating the heat. Air from the blower is blown onto the reflector through the multiple openings in the cover, and the air that has reached the reflector is then released through the multiple openings to the exterior of the light source. This effectively dissipates heat from the reflector, suppressing temperature increases in the light-emitting element.

[0031] Effects of the Invention

[0032] According to the above embodiment, the first gas chamber and the second gas chamber are dry. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a cross-sectional view schematically showing the gas analyzer according to the first embodiment.

[0034] Figure 2 This is a block diagram showing the configuration of a gas analysis device using a gas analyzer.

[0035] Figure 3 This is the circuit diagram of the flow sensor.

[0036] Figure 4 yes Figure 1 A cross-sectional view of the detector along line AA.

[0037] Figure 5 This diagram explains the process of sealing gas into the detector.

[0038] Figure 6 yes Figure 1 A cross-sectional view of the detector of line BB.

[0039] Figure 7 It is a partial cross-sectional view of the detector.

[0040] Figure 8 This is an explanatory diagram of the lid of the drying container.

[0041] Figure 9 This is a cross-sectional view schematically showing a gas analyzer according to the second embodiment.

[0042] Figure 10 This is an illustration of a light source.

[0043] Figure 11 It is a figure which shows the effect of the close contact member.

[0044] Figure 12 This is a cross-sectional view schematically showing a gas analyzer according to a third embodiment. DETAILED DESCRIPTION

[0045] Hereinafter, the present invention will be described in detail based on the drawings showing embodiments of the present invention.

[0046] (Implementation 1)

[0047] Figure 1 This is a cross-sectional view showing an overview of the gas analyzer 1 of embodiment 1. The gas analyzer 1 is used to analyze the concentration of a specific gas component contained in the gas of the analysis object, such as nitric oxide (NO). The specific gas component is an acidic gas component. The gas analyzer 1 includes a light source 2, a chopper 3, a cell 4, and two detectors 5 and 6. A gas is sealed in each of the detectors 5 and 6. The light source 2, the cell 4, and the two detectors 5 and 6 are arranged in sequence. The light source 2 emits continuous infrared light of a fixed intensity toward the cell 4. Infrared light is light whose wavelength belongs to the infrared range. In Figure 1 In the figure, the solid line represents the propagation path of infrared light. Chopper 3 includes an impeller. In chopper 3, the impeller rotates at a constant speed. As the impeller rotates, it passes between light source 2 and pool 4, periodically blocking the infrared light emitted by light source 2. The infrared light emitted by light source 2 intermittently enters pool 4.

[0048] The cell 4 has a cylindrical body 40 with both end faces open. One end face of the cylindrical body 40 is opposite to the light source 2. The other end face of the cylindrical body 40 is opposite to the detector 5. In the cylindrical body 40, a transmission window 41 for transmitting infrared light is embedded in the opening of the end face on the light source 2 side, and a transmission window 42 for transmitting infrared light is also embedded in the opening of the end face on the detector 5 side. The infrared light emitted by the light source 2 enters the cylindrical body 40 through the transmission window 41 and is emitted from the cylindrical body 40 toward the detector 5 through the transmission window 42. As described above, the infrared light emitted by the light source 2 passes through the cylindrical body 40 of the cell 4. The infrared light after passing through the cylindrical body 40 is incident on the detector 5.

[0049] An injection port 40a for injecting the gas to be analyzed is provided on the light source 2 side of the outer surface of the cylinder 40. An exhaust port 40b for discharging the gas to be analyzed is provided on the detector 5 side of the outer side of the cylinder 40. As indicated by the dotted arrow, the gas to be analyzed is injected from the injection port 40a. The injected gas to be analyzed flows through the cylinder 40 of the pool 4. The gas to be analyzed that has flowed through the cylinder 40 is discharged from the exhaust port 40b as indicated by the dotted arrow. When the gas to be analyzed is injected into the cylinder 40, and infrared light passes through the cylinder 40, specific gas components contained in the gas to be analyzed absorb specific wavelength components of the infrared light. The higher the concentration of the specific gas component, the more infrared light is absorbed and the greater the attenuation of the infrared light.

[0050] In addition, there is a situation where the wavelength region of the infrared light absorbed by the gas of the analytical object overlaps with the wavelength region of the infrared light absorbed by the specific gas component, such as water (H2O). In this case, when the infrared light passes through the barrel 40, the interfering gas component contained in the gas of the analytical object also absorbs the infrared light. When the interfering gas component is contained, the attenuation of the infrared light that has passed through the barrel 40 of the pool 4 strictly speaking represents the concentration of the specific gas component and the overall interfering gas component. Below, the example of containing the interfering gas component in the gas of the analytical object is described.

[0051] Detectors 5 and 6 are pneumatic detectors. Pneumatic detectors are thermal detectors that detect the intensity of infrared rays. A measurement object or a specific gas with the same infrared absorption as the measurement object is enclosed in the pneumatic detector. When the gas absorbs infrared rays, it expands and its pressure changes. The pneumatic detector detects this pressure change and outputs the detection result as a signal indicating the intensity of the infrared rays. The pressure change is represented by a change in the capacitance of a condenser microphone configured in the pneumatic detector or a change in the flow rate of the gas flowing through the pneumatic detector. Detectors 5 and 6 are detectors that detect the intensity of infrared rays based on the flow rate of the gas.

[0052] Specifically, the detector 5 includes a cylindrical block 50 with both ends open. One end face of the block 50 faces the cell 4. The other end face of the block 50 faces the detector 6. In the block 50, a first transmission window 51 that transmits infrared light is embedded in the opening of the end face on the cell 4 side. A second transmission window 52 that transmits infrared light is embedded midway in the block 50. In the block 50, a third transmission window 53 that transmits infrared light is embedded in the opening of the end face on the detector 6 side.

[0053] As shown in the attached figure (e.g. Figure 6 ), the shape of the cylindrical block 50 is, as an example, a shape in which a cylindrical cavity is provided inside a quadrangular prism. However, the shape of the block 50 is not limited to this shape, and may be a shape different from the shape in which a cylindrical cavity is provided inside a quadrangular prism.

[0054] Block 50, first transmission window 51, and second transmission window 52 form a first gas chamber 54. Block 50, second transmission window 52, ​​and third transmission window 53 form a second gas chamber 55. Each of first and second gas chambers 54 and 55 is filled with a gas containing a specific gas component. The concentration of the specific gas component in the gas contained in first and second gas chambers 54 and 55 is substantially the same. The gas is sealed within block 50. As described above, the specific gas component is an acidic gas component, such as nitric oxide.

[0055] A communication channel 50a is provided on the side wall of the block 50, connecting the first gas chamber 54 and the second gas chamber 55. A flow sensor 56 is provided midway along the communication channel 50a to detect the flow rate of gas flowing through the communication channel 50a. The gas flowing through the communication channel 50a passes through the flow sensor 56.

[0056] The infrared light that passes through the cylindrical body 40 of the cell 4 passes through the first transmission window 51 and enters the first gas chamber 54. The infrared light that passes through the first gas chamber 54 passes through the second transmission window 52 and enters the second gas chamber 55. The infrared light that passes through the second gas chamber 55 passes through the third transmission window 53 and enters the detector 6. As described above, the infrared light that passes through the cylindrical body 40 of the cell 4 passes through the first gas chamber 54. The infrared light that passes through the first gas chamber 54 passes through the second gas chamber 55. The infrared light that passes through the second gas chamber 55 enters the detector 6.

[0057] When infrared light passes through the first gas chamber 54, the specific gas components contained in the gas filling the first gas chamber 54 absorb the specific wavelength components of the infrared light. As a result, the gas filling the first gas chamber 54 expands. Similarly, when infrared light passes through the second gas chamber 55, the specific gas components contained in the gas filling the second gas chamber 55 absorb the specific wavelength components of the infrared light. As a result, the gas filling the second gas chamber 55 expands. The greater the amount of infrared light absorbed, the greater the expansion of the gas filling the first gas chamber 54 and the second gas chamber 55. Most of the specific wavelength components of the infrared light incident on the detector 5 from the cell 4 are absorbed in the first gas chamber 54, and the amount of infrared light absorbed by the gas filling the second gas chamber 55 is small.

[0058] When infrared light passes through the detector 5, the gas filling the first gas chamber 54 expands more than the gas filling the second gas chamber 55, causing gas to flow from the first gas chamber 54 through the connecting passage 50a to the second gas chamber 55. The stronger the intensity of the specific wavelength component of the infrared light incident on the detector 5, the greater the amount of absorption of the specific wavelength component by the specific gas component contained in the gas filling the first gas chamber 54, and the greater the expansion of the gas filling the first gas chamber 54. Therefore, the difference in the amount of infrared light absorbed by the gas in the first gas chamber 54 and the second gas chamber 55 increases. Consequently, the stronger the intensity of the specific wavelength component of the infrared light incident on the detector 5, the greater the flow rate of gas flowing through the connecting passage 50a.

[0059] As described above, flow sensor 56 detects the flow rate of gas flowing through connecting channel 50a. Furthermore, the higher the overall concentration of the specific gas component and interfering gas components contained in the gas being analyzed, the greater the amount of the specific wavelength component of infrared light absorbed in cell 4. Consequently, the intensity of the specific wavelength component of infrared light incident on detector 5 decreases. The weaker the intensity of the specific wavelength component of infrared light incident on detector 5, the lower the flow rate of gas flowing through connecting channel 50a. Detecting the flow rate of gas flowing through connecting channel 50a is equivalent to detecting the intensity of the specific wavelength component of infrared light incident on detector 5.

[0060] Flow sensor 56 detects the gas flow rate while infrared light from light source 2 is incident on cell 4. When chopper 3 blocks the infrared light, the gas filling first gas chamber 54 and second gas chamber 55 dissipates heat. As a result, the gas shrinks, returning to the state before the infrared light entered detector 5.

[0061] Detector 6 is constructed similarly to detector 5. It includes a cylindrical block 60, a first transmission window 61, a second transmission window 62, a third transmission window 63, and a flow sensor 66. Block 60, first transmission window 61, second transmission window 62, third transmission window 63, and flow sensor 66 correspond to block 50, first transmission window 51, second transmission window 52, ​​third transmission window 53, and flow sensor 56 of detector 5, respectively. As in detector 5, block 60, first transmission window 61, and second transmission window 62 form a first gas chamber 64, while block 60, second transmission window 62, and third transmission window 63 form a second gas chamber 65.

[0062] The first gas chamber 64 and the second gas chamber 65 are filled with a gas containing a specific gas component. A communication channel 60a is provided on the sidewall of the block 60, connecting the first gas chamber 64 and the second gas chamber 65. A flow sensor 66, which detects the flow rate of gas flowing through the communication channel 60a, is located midway along the communication channel 60a. The structure and function of the flow sensor 66 are similar to those of the flow sensor 56 of the detector 5. The gas is sealed within the block 60.

[0063] The infrared light that has passed through the second gas chamber 55 of the detector 5 passes through the first transmission window 61 of the detector 6, enters the first gas chamber 64, and then passes through the first gas chamber 64. The infrared light that has passed through the first gas chamber 64 passes through the second transmission window 62 and enters the second gas chamber 65. The infrared light that has passed through the second gas chamber 65 is emitted to the outside through the third transmission window 63. As described above, the infrared light that has passed through the detector 5 passes through the first gas chamber 64. The infrared light that has passed through the first gas chamber 64 passes through the second gas chamber 65.

[0064] In detector 5, a large portion of specific wavelength components of infrared light are absorbed by specific gas components. Therefore, the intensity of specific wavelength components is low in the infrared light that passes through detector 5. Consequently, the wavelength components of the infrared light absorbed by the gases filling first gas chamber 64 and second gas chamber 65 of detector 6 are mostly those absorbed by interfering gas components. As a result, the higher the concentration of interfering gas components in the gas being analyzed, the weaker the intensity of the infrared light incident on detector 6, and the smaller the gas flow rate detected by flow sensor 66.

[0065] The concentration of a specific gas component contained in the gas filling first gas chamber 64 and second gas chamber 65 of detector 6 is higher than the concentration of the specific gas component contained in the gas filling first gas chamber 54 and second gas chamber 55 of detector 5. For example, the ratio of the specific gas component in the gas filling first gas chamber 64 and second gas chamber 65 of detector 6 is 100%. In this case, the ratio of the specific gas component in the gas filling first gas chamber 54 and second gas chamber 55 of detector 5 is, for example, 10% to 20%, which is less than 100%.

[0066] The intensity of specific wavelength components of infrared light that passes through detector 5 is weak. However, as described above, since the concentration of specific gas components contained in the gas filling first gas chamber 64 and second gas chamber 65 of detector 6 is high, a large amount of infrared light is absorbed in first gas chamber 64 and second gas chamber 65. Therefore, flow sensor 66 can easily detect the flow rate of gas flowing through communication channel 60a.

[0067] Figure 2 This is a block diagram showing the configuration of a gas analyzer 7 using a gas analyzer 1. As described above, the gas analyzer 1 includes a light source 2, a chopper 3, a cell 4, and detectors 5 and 6. The gas analyzer 7 includes the gas analyzer 1 and a concentration calculator 70. The concentration calculator 70 includes two amplifiers 70a and 70b, A / D converters 70c and 70d, a display 70e, a memory 70f, and a control unit 70g.

[0068] Detectors 5 and 6 are connected to amplifiers 70a and 70b, respectively. Amplifiers 70a and 70b are further connected to A / D converters 70c and 70d, respectively. A / D converters 70c and 70d, display 70e, memory 70f, and control unit 70g are connected to an internal bus 70h.

[0069] When the flow rate sensor 56 of detector 5 and the flow rate sensor 66 of detector 6 detect gas flow rates, they output analog flow rate signals representing the detected gas flow rates to amplifiers 70a and 70b, respectively. Amplifiers 70a and 70b amplify the amplitudes of the analog flow rate signals input from detectors 5 and 6, respectively. Amplifiers 70a and 70b output the amplitude-amplified analog flow rate signals to A / D converters 70c and 70d, respectively. A / D converters 70c and 70d convert the analog flow rate signals input from amplifiers 70a and 70b, respectively, into digital flow rate signals. A control unit 70g reads the digital flow rate signals from A / D converters 70c and 70d, respectively. A display unit 70e includes a display panel that displays various values ​​in accordance with instructions from control unit 70g.

[0070] The memory 70f stores a computer program (not shown). The control unit 70g includes a processing unit, such as a CPU (Central Processing Unit), that performs processing. The control unit 70g executes the computer program stored in the memory 70f to perform concentration calculation processing to calculate the concentration of a specific gas component contained in the gas to be analyzed.

[0071] In the concentration calculation process, the control unit 70g calculates the concentration of the specific gas component and the overall interfering gas component contained in the gas of the analysis object based on the flow rate of the gas shown by the flow rate signal input from the flow sensor 56 of the detector 5. Specifically, the control unit 70g calculates the concentration of the specific gas component and the overall interfering gas component based on the flow rate of the gas shown by the flow rate signal input from the flow sensor 56 when the zero-point gas flows through the barrel 40 of the cell 4, and the difference between the flow rate of the gas shown by the flow rate signal input from the flow sensor 56 when the gas of the analysis object flows through the barrel 40. The zero-point gas is a gas composed of gas components that do not absorb infrared light, such as nitrogen (N2). Therefore, even if infrared light passes through the zero-point gas, the zero-point gas does not absorb infrared light.

[0072] The control unit 70g calculates the concentration of the interfering gas component that absorbs a specific wavelength component of infrared light based on the flow rate of the gas indicated by the flow rate signal input from the flow rate sensor 66 of the detector 6. Specifically, the concentration calculation unit 70 calculates the concentration of the interfering gas component based on the difference between the flow rate of the gas indicated by the flow rate signal input from the flow rate sensor 66 when the zero-point gas flows through the cylinder 40 of the cell 4 and the flow rate of the gas indicated by the flow rate signal input from the flow rate sensor 66 when the gas to be analyzed flows through the cylinder 40.

[0073] As described above, the control unit 70g calculates the concentrations of the specific gas component and the interfering gas component contained in the target gas, as well as the concentration of the interfering gas component contained in the target gas. Based on these two calculated concentrations, the control unit 70g accurately calculates the concentration of the specific gas component contained in the target gas. This analyzes the concentration of the specific gas component. The control unit 70g causes the display unit 70e to display the calculated concentration of the specific gas component. This allows the user to confirm the concentration of the specific gas component.

[0074] Figure 3 This is a circuit diagram of the flow sensor 56. The flow sensor 56 has fixed resistors R1 and R2 and thin film resistors Rs1 and Rs2. The resistance value of the thin film resistor Rs1 varies according to the temperature of the thin film resistor Rs1. Similarly, the resistance value of the thin film resistor Rs2 varies according to the temperature of the thin film resistor Rs2. The thin film resistors Rs1 and Rs2 are of the same type, and materials such as platinum or nickel are used in their manufacture. In addition, when current flows through the thin film resistor Rs1, the thin film resistor Rs1 generates heat. The lower the temperature of the thin film resistor Rs1, the smaller the resistance value of the thin film resistor Rs1, and the higher the temperature of the thin film resistor Rs1, the larger the resistance value of the thin film resistor Rs1. The thin film resistor Rs2 functions in the same way as the thin film resistor Rs1.

[0075] The positive electrode of the DC power supply E is connected to one end of each of the fixed resistors R1 and R2. The other end of each of the fixed resistors R1 and R2 is connected to one end of the thin film resistors Rs1 and Rs2. The negative electrode of the DC power supply E and the other ends of the thin film resistors Rs1 and Rs2 are grounded. The fixed resistor R1 and the thin film resistor Rs1 divide the output voltage of the DC power supply E, and output the first divided voltage obtained by dividing the output voltage as a flow signal to the amplifier 70a of the concentration calculation unit 70. Similarly, the fixed resistor R2 and the thin film resistor Rs2 divide the output voltage of the DC power supply E, and output the second divided voltage obtained by dividing the output voltage as a flow signal to the amplifier 70a of the concentration calculation unit 70. The larger the resistance value of the thin film resistor Rs1, that is, the higher the temperature of the thin film resistor Rs1, the higher the first divided voltage. Similarly, the smaller the resistance value of the thin film resistor Rs2, that is, the lower the temperature of the thin film resistor Rs2, the lower the second divided voltage.

[0076] Thin-film resistors Rs1 and Rs2 are exposed to the communication channel 50a. Thin-film resistor Rs1 is positioned on the first gas chamber 54 side of thin-film resistor Rs2. Furthermore, the two thin-film resistors Rs1 and Rs2 are positioned close to each other. When current flows from a DC power supply E through thin-film resistors Rs1 and Rs2, they generate heat. Thin-film resistors Rs1 and Rs2 dissipate heat. When gas does not flow through the communication channel 50a, the amount of heat generated and dissipated equals the amount of heat dissipated, and the temperatures of thin-film resistors Rs1 and Rs2 converge to a constant level.

[0077] When gas flows through the communication channel 50a, it removes heat from the thin-film resistor Rs1. As a result, the temperature of the thin-film resistor Rs1 decreases. The greater the flow rate through the communication channel 50a, the lower the temperature of the thin-film resistor Rs1. As described above, the lower the temperature of the thin-film resistor Rs1, the lower the first divided voltage. Therefore, the greater the flow rate of gas through the communication channel 50a, that is, the stronger the intensity of the specific wavelength component of infrared light incident on the detector 5, the lower the first divided voltage.

[0078] When the gas takes away heat from the thin film resistor Rs1, the temperature of the gas passing through the thin film resistor Rs1 rises. The gas that has taken away heat from the thin film resistor Rs1 passes through the thin film resistor Rs2 close to the thin film resistor Rs1. At this time, the temperature of the thin film resistor Rs2 rises due to the gas whose temperature has risen by taking away heat from the thin film resistor Rs1. The greater the flow rate of gas flowing through the connecting channel 50a, the higher the temperature of the thin film resistor Rs2 rises. As described above, the higher the temperature of the thin film resistor Rs2, the higher the second divided voltage. Therefore, the greater the flow rate of gas flowing through the connecting channel 50a, that is, the stronger the intensity of the specific wavelength component of the infrared light incident on the detector 5, the higher the second divided voltage.

[0079] As described above, the flow sensor 56 detects the flow rate of gas flowing through the communication passage 50a and outputs a first divided voltage and a second divided voltage representing the detected gas flow rate as flow rate signals to the amplifier 70a of the concentration calculation unit 70. The amplifier 70a amplifies the amplitudes of the two flow rate signals input from the flow sensor 56 and outputs the two amplified flow rate signals to the A / D converter 70c. The A / D converter 70c converts the two analog flow rate signals into digital flow rate signals.

[0080] As described above, the structure and function of the flow sensor 66 of the detector 6 are similar to those of the flow sensor 56 of the detector 5. The flow sensor 66 detects the flow rate of gas flowing through the communication channel 60a and outputs a first divided voltage and a second divided voltage representing the detected gas flow rate as flow rate signals to the amplifier 70b of the concentration calculation unit 70. The amplifier 70b amplifies the amplitudes of the two flow rate signals input from the flow sensor 66 and outputs the two amplified flow rate signals to the A / D converter 70d. The A / D converter 70d converts the two analog flow rate signals into digital flow rate signals.

[0081] The following describes in detail the configuration of the detector 5. As described above, the configuration of the detector 6 is the same as that of the detector 5. Therefore, a detailed description of the configuration of the detector 6 will be omitted.

[0082] Figure 4 yes Figure 1 A cross-sectional view of the detector 5 along line AA. Figure 4 As shown, openings 50b and 50c for gas discharge and injection are provided on the outer surface of the cylindrical block 50. A first passage 50d connecting the opening 50b to the first gas chamber 54 is provided on the side wall of the block 50. A sealing component 57 is adhered to the side wall of the block 50 and the peripheral portion of the opening 50b. The sealing component 57 seals the opening 50b by covering the opening 50b. A second passage 50e connecting the opening 50c to the second gas chamber 55 is also provided on the side wall of the block 50. A sealing component 58 is adhered to the side wall of the block 50 and the peripheral portion of the opening 50c. The sealing component 58 seals the opening 50c by covering the opening 50c.

[0083] Figure 5 This is an explanatory diagram of the process of sealing gas into the detector 5. Before the gas is sealed into the detector 5, the sealing members 57 and 58 are cylindrical with both ends open, and the peripheral edges of the openings 50b and 50c are bonded to the side walls of the block 50. The through holes of the sealing members 57 and 58 are connected to the openings 50b and 50c. The sealing members 57 and 58 are made of aluminum or copper, and are easily deformed by external force. In the direction intersecting the axial direction of the sealing member 57, for example, Figure 5 Cut in the direction indicated by the arrow. Figure 4 As shown, the through hole of the sealing member 57 is closed, and the sealing member 57 closes the opening 50b. Similarly, the sealing member 58 is cut along the direction intersecting the axial direction. Figure 4 As shown, the through hole of the sealing member 58 is closed, and the sealing member 58 seals the opening 50c.

[0084] When the gas is sealed in the detector 5, the gas contained in the first gas chamber 54 and the second gas chamber 55 is sucked to the outside through the first passage 50d and the second passage 50e from the through-holes of the sealing parts 57 and 58 using a vacuum pump or the like. As a result, the state of the first gas chamber 54 and the second gas chamber 55 becomes a vacuum state. When the first gas chamber 54 and the second gas chamber 55 are in a vacuum state, a gas containing a specific gas component is injected into the first gas chamber 54 from the through-hole of the sealing part 57, and a gas containing a specific gas component is injected into the second gas chamber 55 from the opening of the sealing part 58. As a result, the first gas chamber 54 and the second gas chamber 55 are filled with the gas containing a specific gas component. After the gas is injected, the sealing parts 57 and 58 are cut off as described above. As a result, the sealing parts 57 and 58 are deformed respectively, and the through-holes are closed. As a result, the openings 50b and 50c are sealed.

[0085] Figure 6 yes Figure 1 A cross-sectional view of the detector 5 along line BB. Figure 6 As shown, the flow sensor 56 is embedded in the side wall of the block 50, and a portion of the flow sensor 56 is exposed to the communication passage 50a. Figure 6 The state of the sealing member 57 shown is a cut-off state, and the sealing member 57 seals the opening 50b.

[0086] The detector 5 also includes a box-shaped drying container 8 containing an acidic desiccant. Examples of acidic desiccant include phosphorus pentoxide, calcium chloride, or magnesium sulfate. The side wall of the block 50 is also provided with an insertion hole 50f for inserting the drying container 8. When the drying container 8 is inserted into the insertion hole 50f, the opening of the insertion hole 50f, which is provided on the outer surface of the block 50, is sealed by a spherical sealing member 59. The sealing member 59 is made of metal, for example. The insertion hole 50f and the sealing member 59 form a storage chamber for storing the drying container 8.

[0087] The bottom surface of the insertion hole 50f is provided with a first passage opening 50g of the first passage 50d. The passage connecting to the opening 50b of the first passage 50d branches into two. One of the two branched passages is connected to the first gas chamber 54. The other of the two branched passages is connected to the first passage opening 50g. Therefore, the storage chamber formed by the insertion hole 50f and the sealing member 59 is connected to the first gas chamber 54 through the first passage 50d.

[0088] In addition, the chamber connected to the storage chamber formed by the insertion hole 50f and the sealing component 59 is not limited to the first gas chamber 54. As a first example, a second passage opening of the second passage 50e can also be provided on the bottom surface of the insertion hole 50f. In this case, for the second passage 50e, the passage connected to the opening 50c is branched into two, and the passage of one of the two passages after branching is connected to the first gas chamber 54, and the passage of the other of the two passages after branching is connected to the second passage opening. As a second example, the passage opening provided on the bottom surface of the insertion hole 50f can also be connected to the connecting channel 50a through a passage. In this case, the storage chamber is connected to the first gas chamber 54 and the second gas chamber 55 through the passage and the connecting channel 50a. Below, an example of the storage chamber being connected to the first gas chamber 54 is described.

[0089] Figure 7 is a partial cross-sectional view of the detector 5. Figure 7 Shown in Figure 6 In the drying container 8, the cover 81 is inserted into the opening of the box body 80, one surface of which is open. The bottom surface of the box body 80 is arranged so as to be closest to the first passage opening 50g provided on the bottom wall of the insertion hole 50f. Figure 6 as well as Figure 7 The drying container 8 is arranged in the storage room in the right side manner. A desiccant is stored in the box body 80.

[0090] Figure 8 It is an explanatory diagram of the lid 81 of the drying container 8 . Figure 8 The upper side of the FIG shows the plane of the cover 81. Figure 8 The lower side of FIG shows the side of the cover 81. Figure 8 As shown, a notch 81a is provided on the cover 81. Figure 7 As shown, the notch 81a extends through the housing 80 in the axial direction, extending from the edge of the cover 81 to the center of the cover 81. In the drying container 8, the housing 80 and the notch 81a form an inlet and outlet 82 for gas.

[0091] like Figure 7As shown, a first gap is provided between the side wall of the housing 80 and the side wall of the insertion hole 50f, and the notch 81a is connected to the first gap. A second gap is provided between the bottom wall of the housing 80 and the side wall of the insertion hole 50f. The gas inlet and outlet 82 of the drying container 8 is connected to the first passage 50d via the notch 81a, the first gap, and the second gap. The gas filling the first gas chamber 54 flows through the first passage 50d, the second gap, the first gap, and the notch 81a in this order, and enters the drying container 8 through the inlet and outlet 82. The gas filling the second gas chamber 55 flows through the connecting passage 50a, the first gas chamber 54, the first passage 50d, the second gap, the first gap, and the notch 81a in this order, and enters the drying container 8 through the inlet and outlet 82. The desiccant in the drying container 8 absorbs moisture from the gas entering the drying container 8. The gas that has absorbed moisture flows out of the drying container 8 through the inlet and outlet 82. The gas exiting the inlet and outlet 82 flows through the notch 81a, the first gap, the second gap, and the first passage 50d in this order, and returns to the first gas chamber 54. The gas exiting the inlet and outlet 82 flows through the notch 81a, the first gap, the second gap, the first passage 50d, the first gas chamber 54, and the communication channel 50a in this order, and returns to the second gas chamber 55.

[0092] As described above, in detector 5, the gas filling first and second gas chambers 54, 55 enters drying container 8, where the moisture contained in the gas is absorbed by the desiccant. Consequently, first and second gas chambers 54, 55 remain dry. Consequently, infrared light is not absorbed by moisture within detector 5.

[0093] As described above, in the detector 5, when a gas containing a specific gas component is injected into the first gas chamber 54 and the second gas chamber 55, before the openings 50b and 50c are sealed, the gas that has respectively entered the first gas chamber 54 and the second gas chamber 55 is sucked to the outside through the first passage 50d and the second passage 50e using a vacuum pump or the like. As a result, the state inside the block 50 becomes a vacuum state. Thereafter, the gas containing a specific gas component is sealed in the block 50, and the air pressure inside the block 50 returns to atmospheric pressure. After the gas is sealed, the openings 50b and 50c are sealed. In addition, in the gas inside the sealed block 50, there is sometimes a trace amount of moisture contained in the gas containing the specific gas component, or a trace amount of moisture contained in the sealing device and adhesive, etc.

[0094] When a desiccant is stored in the storage chamber formed by the insertion hole 50f and the sealing part 59, if the desiccant is deliquescent, the desiccant absorbs moisture and a portion of the desiccant changes to a liquid state. In a state where the desiccant is stored in the storage chamber formed by the insertion hole 50f and the sealing part 59, the gas is sealed into the detector 5 after the inside of the detector 5 is evacuated. When the desiccant deliquesces during the process of evacuating the inside of the detector 5, there is a possibility that the deliquesced liquid will scatter. When the liquid scatters, the deliquesced liquid will adhere to the first transmission window 51, the second transmission window 52, ​​or the third transmission window 53 provided in the first gas chamber 54 and the second gas chamber 55, resulting in the possibility of blurring. When infrared light passes through the blurred transmission window, the intensity of the infrared light is attenuated.

[0095] In this case, the gas flow rate detected by the flow sensor 56 cannot accurately represent the intensity of the specific wavelength component of the infrared light entering the first gas chamber 54. However, in the drying container 8, the gas inlet and outlet 82 is located at a different location than the location opposite the first passage opening 50g of the first passage 50d. Specifically, it is located on the lid 81 of the drying container 8, on the side of the drying container 8 opposite the bottom wall of the housing 80. Therefore, even if liquid scatters, it is unlikely to enter the first gas chamber 54 or the second gas chamber 55, and the likelihood of blurring the first, second, or third transmission windows 51, 52, or 53 is low. As a result, the infrared light generated when passing through the first, second, or third transmission windows 51, 52, or 53 is barely attenuated. The surface of the drying container 8 that faces the bottom of the housing 80 is the surface of the lid 81.

[0096] In addition, in the drying container 8, the location where the gas inlet and outlet 82 is provided is not limited to the cover 81 of the drying container 8, and may be, for example, the side wall of the box 80. Figure 7 As shown, the bottom wall of the box body 80 of the drying container 8 is flat. However, the bottom wall of the box body 80 can also be curved.

[0097] Furthermore, since the specific gas component is an acidic gas component and an acidic substance is used as the desiccant, a neutralization reaction between the gas component and the desiccant does not occur, and the gas contained in the first gas chamber 54 and the second gas chamber 55 is appropriately dried.

[0098] As described above, the detector 6 is configured similarly to the detector 5. Therefore, the detector 6 can achieve the same effects as those achieved by the detector 5.

[0099] In addition, in a case where the intensity of the infrared light incident on the detector 6 is sufficiently strong, the concentration of the specific gas component contained in the gas filled in the first gas chamber 64 and the second gas chamber 65 of the detector 6 can be lower than the concentration of the specific gas component contained in the gas filled in the first gas chamber 54 and the second gas chamber 55 of the detector 5.

[0100] In addition, in a case where the interfering gas component is contained in the gas that is not the analysis target, the control section 70g of the concentration calculation section 70 can calculate the concentration of the specific gas component on the basis of the flow rate of the gas indicated by the flow rate signal input from the flow rate sensor 56 of the detector 5. In this case, the gas analyzer 1 can be configured to be devoid of the detector 6. Further, the specific gas component is not limited to the acidic gas component, and can be an alkaline gas component. In this case, an alkaline substance is used as the desiccant.

[0101] (Embodiment 2)

[0102] Figure 9 is a sectional view that schematically shows the gas analyzer 1a of Embodiment 2.

[0103] Hereinafter, for Embodiment 2, points different from Embodiment 1 will be described. The other configurations are common to Embodiment 1 except for the configurations described later. Therefore, the configurations common to Embodiment 1 are attached with the same reference numerals as those of Embodiment 1 and the description thereof will be omitted.

[0104] As one of the light sources used in the conventional gas analyzer provided with a detector that detects the intensity of infrared light, there is a light source in which a light-emitting element that emits infrared light is housed in a reflection body in the shape of a box with one face open. For example, the light-emitting element is disposed on the bottom face of the reflection body, and a part of the infrared light emitted from the light-emitting element is reflected by the inner surface of the reflection body and propagates toward the cell. In a case where the light-emitting element emits light, heat is generated in the light-emitting element. The generated heat is conducted to the reflection body, and the reflection body dissipates the heat. The air blower blows air toward the reflection body. Thereby, the reflection body efficiently dissipates the heat.

[0105] However, in a case where the air blown by the air blower enters the reflection body, the temperature of the light-emitting element fluctuates due to the air. The intensity of the infrared light emitted from the light-emitting element fluctuates according to the temperature of the light-emitting element. Therefore, in a case where the temperature of the light-emitting element fluctuates due to the air, the intensity of the infrared light emitted from the light source is unstable. In this case, the concentration of the specific gas component contained in the gas that is the analysis target cannot be appropriately calculated.

[0106] Embodiment 2 aims to provide a gas analyzer in which air does not enter the reflection body.

[0107] The gas analyzer 1a of embodiment 2 includes a cell 4 and detectors 5 and 6 similarly to the gas analyzer 1 of embodiment 1. The gas analyzer 1a of embodiment 2 includes a light source 9 instead of the light source 2. In the gas analyzer 1a, a blower F for blowing air toward the light source 9 is disposed near the light source 9.

[0108] A power source (not shown) supplies power to light source 9 via a switch (not shown). When the switch is on, light source 9 emits infrared light of constant intensity toward pool 4. When the switch is off, light source 9 stops emitting infrared light. The switch is alternately switched on and off repeatedly. Thus, the infrared light emitted by light source 9 intermittently enters pool 4, similar to the infrared light emitted by light source 2 in Embodiment 1.

[0109] In addition, similarly to the first embodiment, the gas analyzer 1 a may be configured without the detector 6 .

[0110] Figure 10 : is an explanatory diagram of the light source 9. Figure 10 Figure 2 shows a cross-section, side view, and plan view of light source 9. In light source 9, a reflector 91, which is box-shaped and open on one side, has a bottom wall 91a disposed on the surface of a rectangular substrate 90. Bottom wall 91a is circular. In reflector 91, side walls 91b extend obliquely from the periphery of bottom wall 91a, expanding outward from bottom wall 91a. Therefore, the area of ​​the opening of reflector 91 is larger than the area of ​​bottom wall 91a.

[0111] like Figure 10 As shown, in light source 9, a light-emitting element 92 emitting infrared light is disposed at the center of bottom wall 91a and housed within reflector 91. Light-emitting element 92 is, for example, a filament. A portion of the infrared light emitted by light-emitting element 92 propagates toward the open surface of reflector 91, i.e., cell 4. Another portion of the infrared light emitted by light-emitting element 92 is reflected by the inner surface of bottom wall 91a or side wall 91b and propagates toward the open surface of reflector 91.

[0112] An elastic annular contact member 93 is disposed on the end surface of the side wall 91b of the reflector 91. The contact member 93 is a so-called O-ring. Figure 9 as well as Figure 10 As shown, in the light source 9, a cylindrical cover 94 covers the outer surface of the side wall 91b. The cover 94 is provided on the plate surface of the substrate 90. Figure 9 As shown, the cover 94 protrudes toward the pool 4 further than the contact member 93 .

[0113] like Figure 9As shown, in the pool 4, a portion of the transmissive window 41 is exposed outward from the end surface of the cylindrical body 40 on the light source 9 side. The exposed portion of the transmissive window 41 is embedded in the cover 94 of the light source 9. The transmissive window 41 is pushed toward the bottom wall 91a of the reflector 91 until the end surface of the cylindrical body 40 on the light source 9 side contacts the end surface of the cover 94. As a result, the contact member 93 is in close contact with the peripheral edge of the opening of the reflector 91 and the peripheral edge of the transmissive window 41.

[0114] like Figure 10 As shown, the cover 94 is provided with a plurality of openings 94a extending inward and outward. The reflector 91 is made of a material with high thermal conductivity, such as metal. A power source supplies power to the light-emitting element 92 via a switch. When the switch is on, the power source supplies power to the light-emitting element 92, causing it to emit infrared light. When the switch is off, the light-emitting element 92 stops emitting light.

[0115] When light-emitting element 92 emits infrared light, it generates heat. The heat generated by light-emitting element 92 is conducted to reflector 91, where it dissipates the heat. Air blower F blows air toward reflector 91. The air blown by air blower F passes through multiple openings 94a in cover 94 and hits sidewall 91b of reflector 91. The air that hits sidewall 91b then flows out of light source 9 through multiple openings 94a. Consequently, reflector 91 efficiently dissipates heat, suppressing any temperature rise in light-emitting element 92.

[0116] As described above, the contact member 93 is in close contact with the reflector 91 and the transmissive window 41 of the cell 4. Therefore, the air blown by the blower F does not enter the reflector 91. If the air blown by the blower F enters the reflector 91, the temperature of the light-emitting element 92 in the reflector 91 fluctuates, and the intensity of the infrared light emitted from the light source 9 to the cell 4 becomes unstable, making it impossible to properly calculate the concentration of a specific gas component contained in the gas to be analyzed.

[0117] Figure 11 : is a diagram showing the effect of the contact member 93. As described in the description of the first embodiment, the concentration calculation unit 70 calculates the concentration of a specific gas component based on the flow rate of the gas indicated by the flow rate signal input from the flow rate sensors 56 and 66 of the detectors 5 and 6. Figure 10 Graph 1 shows the transitions of two concentrations of a specific gas component calculated when zero-point gas flows within the cylinder 40 of the cell 4. One concentration is calculated by a gas analyzer without the contact member 93, and is represented by a thin solid line. The other concentration is calculated by the concentration calculation unit 70 of the gas analyzer 1a, and is represented by a thick solid line. The horizontal axis represents time for these concentration transitions. Since the specific gas component is not present within the cylinder 40, its concentration is effectively zero.

[0118] like Figure 11 As shown, when the close-fitting member 93 is not used, the calculated concentration fluctuates significantly, even though the actual concentration is zero. This indicates that the error in the calculated concentration is large. On the other hand, the concentration calculated by the concentration calculation unit 70 of the gas analyzer 1a using the close-fitting member 93 remains almost unchanged, and the fluctuation range of the concentration is also small. This indicates that the error in the calculated concentration is small.

[0119] As described above, in the gas analyzer 1a of Embodiment 2, since there is no gap between the reflector 91 of the light source 9 and the transmissive window 41 of the cell 4, the air blown by the blower F does not enter the reflector 91, and the temperature of the light-emitting element 92 does not fluctuate due to the wind. Therefore, the intensity of the infrared light emitted by the light source 9 is stable, and the concentration calculation unit 70 can calculate an accurate concentration.

[0120] The configurations of the detectors 5 and 6 in the second embodiment are the same as those in the first embodiment. Therefore, the detectors 5 and 6 in the second embodiment can each achieve the same effects as those in the first embodiment.

[0121] In addition, in embodiment 2, the method for generating intermittent infrared light is not limited to the method of rotating the chopper 3. For example, as in embodiment 1, intermittent infrared light can be generated using the chopper 3. In this method, when the chopper 3 rotates, the impeller of the chopper 3 passes, for example, between the pool 4 and the detector 5. In addition, in embodiment 1, the method for generating intermittent infrared light is not limited to the method of rotating the chopper 3. For example, as in embodiment 2, a method of alternately and repeatedly switching the switch arranged on the path for the power supply to the light source 2 to be connected and disconnected can be used.

[0122] In Embodiment 1, light source 2 only needs to emit infrared light. Therefore, the configuration of light source 2 in Embodiment 1 may be the same as or different from that of light source 9.

[0123] (Implementation 3)

[0124] In Embodiment 2, detectors 5 and 6 enclosing a gas containing a specific gas component are used as detectors for detecting the intensity of incident infrared light. However, detectors for detecting the intensity of infrared light are not limited to detectors enclosing a gas.

[0125] Hereinafter, Embodiment 3 will be described with respect to the differences from Embodiment 2. Except for the configuration described below, the other configurations are the same as those of Embodiment 2. Therefore, the same reference numerals as those of Embodiment 2 are assigned to the configurations common to Embodiment 2, and their descriptions are omitted.

[0126] Figure 12 This is a cross-sectional view schematically illustrating a gas analyzer 1b according to Embodiment 3. In gas analyzer 1b, the intensity of specific wavelength components of infrared light transmitted through cylindrical body 40 of cell 4 is detected by detector D. In detector D, infrared light transmitted through cylindrical body 40 of cell 4 passes through multiple filters. Only predetermined wavelength components of the infrared light pass through the filters. The wavelength components transmitted through the multiple filters differ from one another. The intensities of the multiple infrared light components transmitted through each of the multiple filters, i.e., the intensities of the multiple wavelength components of the infrared light transmitted through cylindrical body 40 of cell 4, are detected by multiple light-receiving elements.

[0127] Detector D detects the intensity of a specific wavelength component of infrared light that has passed through cylindrical body 40 of cell 4, as well as the intensity of a reference wavelength component that has not been absorbed within cylindrical body 40 of cell 4. In gas analysis device 7 using gas analyzer 1b, detector D is connected to amplifier 70a of concentration calculation unit 70. Detector D outputs an analog first intensity signal representing the intensity of the detected specific wavelength component and an analog second intensity signal representing the intensity of the detected reference wavelength component to amplifier 70a of concentration calculation unit 70.

[0128] The amplifier 70a amplifies the amplitudes of the first and second intensity signals and outputs the amplified analog first and second intensity signals to the A / D converter 70c. The A / D converter 70c converts the analog first intensity signal into a digital second intensity signal, and vice versa. The control unit 70g reads the first and second intensity signals from the A / D converter 70c. In Embodiment 3, the concentration calculator 70 may not include the amplifier 70b and the A / D converter 70d.

[0129] During the concentration calculation process, the control unit 70g of the concentration calculation unit 70 calculates the concentration of a specific gas component contained in the target gas based on the two intensities indicated by the first intensity signal and the second intensity signal input from the detector D. Specifically, the concentration calculation unit 70 calculates the concentration of the specific gas component based on the difference between the intensity of the specific wavelength component indicated by the first intensity signal and the intensity of the reference wavelength component indicated by the second intensity signal. This allows analysis of the concentration of the specific gas component.

[0130] Even in the gas analyzer 1b configured as described above, if the air blown by the blower F enters the reflector 91, the temperature of the light-emitting element 92 will fluctuate, and the intensity of the infrared light emitted by the light source 9 will become unstable. However, since the light source 9 of Embodiment 3 is configured similarly to Embodiment 2, there is no gap between the reflector 91 of the light source 9 and the transmission window 41 of the cell 4. Therefore, the air blown by the blower F does not enter the reflector 91, and the temperature of the light-emitting element 92 does not fluctuate due to the wind. The intensity of the infrared light emitted by the light source 9 is stable, and the control unit 70g of the concentration calculation unit 70 can calculate an accurate concentration. Furthermore, as in Embodiment 2, in the light source 9, the reflector 91 efficiently dissipates heat, which can suppress the temperature increase of the light-emitting element 92.

[0131] Furthermore, in Embodiment 3, the number of specific gas components whose concentrations are detected is not limited to one; for example, it may be two or more. In this case, detector D detects the intensities of multiple specific wavelength components absorbed by each of the multiple gas components, and also detects the intensity of a reference wavelength component. The control unit 70g of the concentration calculation unit 70 calculates the concentration of one specific gas component using the intensity of one specific wavelength component and the intensity of the reference wavelength component. Similarly, the control unit 70g calculates the concentration of another specific gas component. When the number of specific gas components is three, examples of the three specific gas components include carbon dioxide, carbon monoxide, and hydrocarbons.

[0132] A gas analyzer according to one aspect of Embodiment 2 or Embodiment 3 is used to analyze the concentration of a specific gas component contained in a target gas and absorbing a specific wavelength component of infrared light. The gas analyzer comprises: a light source that emits infrared light; a cell through which the target gas flows and through which the infrared light emitted by the light source passes; and an intensity detection unit that detects the intensity of the specific wavelength component of the infrared light after passing through the cell. The cell has a transmission window through which the infrared light emitted by the light source passes. The light source comprises: a light-emitting element that emits infrared light; a reflector in the form of a box with one open surface that houses the light-emitting element and reflects the infrared light emitted by the light-emitting element; and an annular contact member that contacts the periphery of the opening of the reflector and the periphery of the transmission window. In Embodiments 2 and 3, detectors 5 and D, respectively, function as intensity detection units.

[0133] Preferably, the gas analyzer according to one aspect of embodiment 2 or embodiment 3 includes a blower, the light source has a cylindrical cover covering the side surface of the reflector, the cover has a plurality of openings, and the blower blows air toward the cover.

[0134] The technical features (constituent elements) described in Embodiments 1 to 3 can be combined with each other, and new technical features can be formed by the combination.

[0135] The disclosed embodiments 1 to 3 are illustrative in all respects and should not be construed as restrictive. The scope of the present invention is indicated by the claims rather than the above, and is intended to include all modifications equivalent to the claims and within the scope of the claims.

[0136] Description of Reference Numerals

[0137] 1.1a Gas analyzer

[0138] 2.9 Light Source

[0139] 4 Pools

[0140] 5.6 Detector

[0141] 8 Drying container

[0142] 41 Through the Window

[0143] 50a, 60a connecting channels

[0144] 50d First access

[0145] 50f Insertion hole (part of the storage chamber)

[0146] 50g first access port

[0147] 54, 64 First gas chamber

[0148] 55, 65 Second gas chamber

[0149] 56, 66 flow sensors

[0150] 59 Sealed part (part of the storage room)

[0151] 82 Entrance and Exit

[0152] 91 reflector

[0153] 92 light-emitting elements

[0154] 93 Close fitting parts

[0155] 94 Covering

[0156] 94a Opening

[0157] F Blower

Claims

1. A detector for detecting the intensity of infrared light, characterized in that: have: A first gas chamber is filled with a gas containing an acidic gas component, and infrared light passes through the first gas chamber; a second gas chamber filled with gas containing the gas component, and the infrared light that has passed through the first gas chamber passes through the second gas chamber; a communication channel, connecting the first gas chamber and the second gas chamber; a flow sensor for detecting the flow of gas flowing through the communication channel; as well as The storage chamber is connected to the first gas chamber or the second gas chamber through a passage, and stores a drying container containing an acidic desiccant. The storage room is provided with a passage opening of the passage, The drying container is provided with a gas inlet and outlet at a position different from the position facing the passage opening. The inlet and outlet are in communication with the passage.

2. The detector according to claim 1, characterized in that The gas component is nitric oxide, The desiccant is phosphorus pentoxide, calcium chloride or magnesium sulfate.

3. A detector for detecting the intensity of infrared light, characterized in that: have: a first gas chamber filled with gas and through which infrared light passes; a second gas chamber filled with gas, through which the infrared light passing through the first gas chamber passes; a communication channel, connecting the first gas chamber and the second gas chamber; a flow sensor for detecting the flow of gas flowing through the communication channel; as well as The storage chamber is connected to the first gas chamber or the second gas chamber through a passage, and stores a drying container containing a desiccant. The storage room is provided with a passage opening of the passage, The drying container is provided with a gas inlet and outlet at a position different from the position facing the passage opening. The inlet and outlet are in communication with the passage.

4. A gas analyzer for analyzing the concentration of a specific gas component contained in a gas to be analyzed and absorbing a specific wavelength component of infrared light, characterized in that: have: The detector according to any one of claims 1 to 3; a light source, emitting infrared light, and a cell through which the gas of the analytical object flows, The gas filled in the first gas chamber and the second gas chamber contains the specific gas component. The infrared light emitted by the light source passes through the cell, The infrared light after passing through the cell passes through the first gas chamber of the detector, The concentration is calculated based on the flow rate detected by the flow sensor.

5. The gas analyzer according to claim 4, characterized in that The number of the detectors is two, The infrared light after passing through the cell passes through the first gas chamber of the detector on one side, The infrared light that has passed through the second gas chamber of one detector passes through the first gas chamber of the other detector. The concentration is calculated based on two flow rates detected by two flow sensors included in the two detectors.

6. The gas analyzer according to claim 5, characterized in that The concentration of the specific gas component contained in the first gas chamber and the second gas chamber of the other detector is higher than the concentration of the specific gas component contained in the first gas chamber and the second gas chamber of the one detector.

7. The gas analyzer according to any one of claims 4 to 6, characterized in that The cell has a transmission window through which the infrared light emitted by the light source transmits. The light source has: a light-emitting element that emits infrared light; a reflector in the shape of a box with one side open, housing the light emitting element and reflecting the infrared light emitted by the light emitting element; and The annular contact member is in close contact with the peripheral edge of the opening of the reflector and the peripheral edge of the transmission window.

8. The gas analyzer according to claim 7, characterized in that The gas analyzer is provided with a blower, The light source has a cylindrical cover that covers the side surface of the reflector. The cover is provided with a plurality of openings, The air blower blows air toward the cover.

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