Detectors and Gas Analyzers

Abstract

This detector is provided with: a first gas chamber (54) through which infrared light is transmitted; and a second gas chamber through which the infrared light having been transmitted through the first gas chamber (54) is transmitted. The first gas chamber (54) and the second gas chamber are both filled with gas. A flow sensor is for detecting a flow rate of the gas flowing through a communication passage. A drying container (8) having a desiccant agent disposed therein is housed in a housing chamber that comprises an insertion hole (50f) and a sealing member (59). The housing chamber is connected to the first gas chamber (54) via a first passage (50d).

Description

[Technical field]

[0001] The present disclosure relates to a detector for detecting the intensity of infrared light and a gas analyzer including the detector. [Background technology]

[0002] Conventionally, the non-dispersive infrared absorption method has been used to analyze gas components. One of the devices that analyze gas components is a gas analyzer that uses a detector that detects the intensity of infrared light. One of the detectors used in this gas analyzer is a detector that contains a gas that contains a specific gas component. The specific gas component is a component that absorbs a specific wavelength component of infrared light. In a gas analyzer that uses a detector that contains a gas, a light source that emits infrared light, a cell in which the gas to be analyzed flows, and a detector are arranged side by side. The infrared light emitted by the light source passes through the cell. The infrared light that passes through the cell is incident on the detector.

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

[0004] The detector includes a first gas chamber and a second gas chamber. teeth It is filled with gas containing a specific gas component. The first gas chamber and the second gas chamber are connected by a connecting path. Infrared light incident on the detector passes through the first gas chamber and then the second gas chamber. In the first gas chamber, the specific gas component absorbs a specific wavelength component of the infrared light. The specific wavelength component of the infrared light that passes through the first gas chamber is absorbed by a specific gas component of the gas contained in the second gas chamber. When infrared light is absorbed, the gas contained in the first gas chamber and the second gas chamber expands. The greater the amount of infrared light absorbed, the greater the gas expands.

[0005] With respect to the infrared light that enters the detector, most of the specific wavelength component is absorbed by the gas filling the first gas chamber, and the amount of infrared light absorbed by the gas filling the second gas chamber is small. Therefore, when infrared light enters the detector, gas flows from the first gas chamber to the second gas chamber through the connecting passage. The detector detects the flow rate of the gas flowing through the connecting passage. The stronger the intensity of the specific wavelength component of the infrared light that enters the detector, the greater the difference in the amount of infrared light absorbed by the gas in the first gas chamber and the second gas chamber. The greater the difference in the amount of infrared light absorbed by the gas in the first gas chamber and the second gas chamber, the greater the flow rate of the gas flowing through the connecting passage. Therefore, detection of the gas flow rate corresponds to detection of the intensity of the specific wavelength component of infrared light.

[0006] The greater the amount of a specific gas component contained in the gas to be analyzed, i.e., 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 path. The concentration of the specific gas component is calculated based on the flow rate of the gas detected by the detector. An example of such a gas analyzer is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2002-131230 A Summary of the Invention [Problem to be solved by the invention]

[0008] The wavelength region of infrared light absorbed by a specific gas component may overlap with the wavelength region of infrared light absorbed by moisture. In this case, when moisture is present 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, when moisture is present in the detector, i.e., when the detector is not dry, the concentration of the specific gas component cannot be measured accurately.

[0009] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a detector in which the first gas chamber and the second gas chamber are dry, and a gas analyzer including the detector. [Means for solving the problem]

[0010] A detector according to one embodiment of the present disclosure is a detector for detecting the intensity of infrared light, and includes a first gas chamber filled with a gas containing an acidic gas component and through which infrared light passes, a second gas chamber filled with a gas containing the gas component and through which the infrared light that has passed through the first gas chamber passes, a communication path connecting the first gas chamber and the second gas chamber, a flow sensor that detects the flow rate of gas flowing through the communication path, and a storage chamber that is connected to the first gas chamber or the second gas chamber by a passage and that stores a drying container containing an acidic desiccant.

[0011] According to the above aspect, 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. Therefore, the first gas chamber and the second gas chamber are dry. Also, an acidic gas component is contained in the gas, and an acidic substance is used as the desiccant. Therefore, 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.

[0012] In a detector according to one aspect of the present disclosure, the gas component is nitric oxide and the desiccant is diphosphorus pentoxide, calcium chloride or magnesium sulfate.

[0013] According to the above aspect, the first gas chamber and the second gas chamber contain a gas containing nitric oxide, and diphosphorus pentoxide, calcium chloride or magnesium sulfate is used as the desiccant.

[0014] In a detector according to one aspect of the present disclosure, a gas inlet / outlet is provided in the drying container at a location other than the location opposite the passage mouth of the passage provided in the storage chamber, and the inlet / outlet is connected to the passage.

[0015] According to the above aspect, in the case where the desiccant is accommodated in the accommodation chamber, if the desiccant has deliquescence, the desiccant absorbs moisture and a part of the desiccant changes to a liquid state. The gas is filled into the detector after the detector is evacuated while the desiccant is accommodated in the accommodation chamber of the detector. If the desiccant is deliquescent in the process of evacuating the detector, the deliquescent liquid may scatter. If the liquid scatters, the deliquescent liquid may adhere to an infrared light transmission window or the like provided in the first gas chamber or the second gas chamber, resulting in fogging. If infrared light passes through a cloudy transmission window, the intensity of the infrared light is attenuated.

[0016] In this case, the flow rate of the gas detected by the flow sensor does not accurately indicate the intensity of a 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 location different from the location facing the passage opening. Therefore, even if liquid is splashed, the splashed liquid is unlikely to enter the first gas chamber or the second gas chamber, and the possibility of fogging up the transmission window is low.

[0017] A detector according to one embodiment of the present disclosure is a detector for detecting the intensity of infrared light, comprising: a first gas chamber filled with gas and through which infrared light passes; a second gas chamber filled with gas and through which infrared light that has passed through the first gas chamber passes; a communication passage connecting the first gas chamber and the second gas chamber; a flow sensor detecting the flow rate of gas flowing through the communication passage; and a storage chamber connected to the first gas chamber or the second gas chamber by a passage and in which a drying container containing a desiccant is stored, wherein a gas inlet / outlet is provided in the drying container at a position different from the position facing the passage opening of the passage provided in the storage chamber, and the inlet / outlet is connected to the passage.

[0018] According to the above aspect, the gas filled 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. Therefore, the first gas chamber and the second gas chamber are dry. In the drying container, a gas inlet / outlet is provided at a location different from the location facing the passage opening of the passage provided in the storage chamber. Therefore, as described above, even if liquid is splashed, the splashed liquid is unlikely to enter the first gas chamber or the second gas chamber, and the possibility of fogging occurring on the transmission window is low.

[0019] A gas analyzer according to one embodiment of the present disclosure is a gas analyzer for analyzing the concentration of a specific gas component that is contained in a gas to be analyzed and absorbs a specific wavelength component of infrared light, the gas analyzer comprising the above-mentioned detector, a light source that emits infrared light, and a cell through which the gas to be analyzed 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, and the infrared light that has passed through the cell passes through the first gas chamber of the detector, and the concentration is calculated based on the flow rate detected by the flow sensor.

[0020] According to the above aspect, the amount of infrared light absorbed by a specific gas component varies depending on the concentration of the specific gas component contained in the gas to be analyzed flowing through the cell, and therefore the intensity of the specific wavelength component of the infrared light transmitted through the cell varies. The flow rate of the gas flowing through the communication path of the detector, i.e., the flow rate of the gas detected by the flow sensor, varies depending on the intensity of the specific wavelength component of the infrared light transmitted through the cell. Therefore, the concentration is detected based on the flow rate detected by the flow sensor. The detection of the gas flow rate corresponds to the detection of the intensity of the specific wavelength component of the infrared light.

[0021] In a gas analyzer according to one embodiment of the present disclosure, the number of detectors is two, the infrared light that passes through the cell passes through a first gas chamber of one of the detectors, and the infrared light that passes through a second gas chamber of the one of the detectors passes through a first gas chamber of the other detector, and the concentration is calculated based on two flow rates detected by two flow sensors possessed by the two detectors.

[0022] According to the above aspect, when the gas to be analyzed contains, in addition to the specific gas component, an interference 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 caused when the infrared light passes through the cell indicates the concentration of the specific gas component and the total interference gas component contained in the gas to be analyzed. With respect to the infrared light that passes through one of the detectors, the intensity of the specific wavelength component is close to zero. Therefore, the attenuation of the infrared light that passes through one of the detectors indicates the concentration of the interference gas component, and the flow rate of the gas corresponding to this concentration is detected by the other detector. Therefore, the concentration of the specific gas component contained in the gas to be analyzed can be accurately calculated based on the outputs of the two detectors.

[0023] In a gas analyzer according to one embodiment of the present disclosure, 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.

[0024] According to the above aspect, the intensity of the infrared light transmitted through one of the detectors is weak, but the concentration of the specific gas component contained in the first gas chamber and the second gas chamber of the other detector is high, so that the gas flow rate can be easily detected.

[0025] In a gas analyzer according to one aspect of the present disclosure, the cell has a transparent 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 box-like reflector with one open side that houses the light-emitting element and reflects the infrared light emitted by the light-emitting element, and an annular adhesion member that is in close contact with the peripheral edge of the opening of the reflector and the peripheral edge of the transparent window.

[0026] According to the above aspect, since there is no gap between the reflector and the transmission window, wind does not enter the reflector, and the temperature of the light-emitting element does not fluctuate due to wind. Normally, the intensity of infrared light emitted by the light-emitting element fluctuates according to the temperature of the light-emitting element. However, since the temperature of the light-emitting element does not fluctuate due to wind, the intensity of infrared light emitted by the light source is stable.

[0027] A gas analyzer according to one aspect of the present disclosure includes a blower, the light source having a cylindrical covering body that covers a side surface of the reflector, the covering body having a plurality of openings, and the blower blowing air toward the covering body.

[0028] According to the above aspect, when the reflector is made of a material with high thermal conductivity, such as a metal, the heat generated by the light emitting element is conducted to the reflector, which dissipates the heat. The wind from the blower hits the reflector through the multiple openings in the cover, and the wind that hits the reflector goes out to the outside of the light source through the multiple openings. Therefore, the reflector efficiently dissipates heat, and the temperature rise of the light emitting element is suppressed. Effect of the Invention

[0029] According to the above aspect, the first gas chamber and the second gas chamber are dry. [Brief description of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view showing an outline of a gas analyzer in a first embodiment. [Diagram 2] FIG. 1 is a block diagram showing a configuration of a gas analysis device using a gas analyzer. [Diagram 3] FIG. 2 is a circuit diagram of a flow sensor. [Figure 4] 2 is a cross-sectional view of the detector taken along line AA in FIG. 1. [Diagram 5] FIG. 4 is an explanatory diagram of a process for sealing a gas in a detector. [Figure 6] 2 is a cross-sectional view of the detector taken along line BB in FIG. 1. [Figure 7] FIG. 2 is a partial cross-sectional view of a detector. [Figure 8] FIG. 2 is an explanatory diagram of a lid of a drying container. [Figure 9] FIG. 11 is a cross-sectional view showing an outline of a gas analyzer in a second embodiment. [Figure 10] FIG. [Figure 11] 13 is a graph showing the effect of a contact member. [Figure 12]FIG. 11 is a cross-sectional view showing an outline of a gas analyzer according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, the present disclosure will be described in detail with reference to the drawings showing embodiments thereof. (Embodiment 1) FIG. 1 is a cross-sectional view showing an outline of a gas analyzer 1 in the first embodiment. The gas analyzer 1 is used to analyze the concentration of a specific gas component, for example, nitric oxide (NO), contained in a gas to be analyzed. 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. 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 this order. The light source 2 emits continuous infrared light with a constant intensity toward the cell 4. The infrared light is light whose wavelength belongs to the infrared range. In FIG. 1, the solid line indicates the propagation path of the infrared light. The chopper 3 has an impeller. The chopper 3 rotates the impeller at a constant speed. When the impeller rotates, the impeller passes between the light source 2 and the cell 4 and periodically blocks the infrared light emitted by the light source 2. The infrared light emitted by the light source 2 is intermittently incident on the cell 4.

[0032] The cell 4 has a cylinder 40 with both end faces open. One end face of the cylinder 40 faces the light source 2. The other end face of the cylinder 40 faces the detector 5. In the cylinder 40, a transmission window 41 that transmits infrared light is fitted into the opening of the end face on the light source 2 side, and a transmission window 42 that transmits infrared light is also fitted into the opening of the end face on the detector 5 side. The infrared light emitted by the light source 2 enters the cylinder 40 through the transmission window 41 and is emitted from the cylinder 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 cylinder 40 of the cell 4. The infrared light that has passed through the cylinder 40 is incident on the detector 5.

[0033] An inlet 40a is provided on the light source 2 side of the outer surface of the cylinder 40 for injecting the gas to be analyzed. An outlet 40b is provided on the detector 5 side of the outside of the cylinder 40 for discharging the gas to be analyzed. As shown by the dashed arrow, the gas to be analyzed is injected from the inlet 40a. The injected gas to be analyzed flows through the cylinder 40 of the cell 4. The gas to be analyzed that has flowed through the cylinder 40 is discharged from the outlet 40b as shown by the dashed arrow. When the gas to be analyzed is injected into the cylinder 40 and infrared light passes through the cylinder 40, a specific gas component contained in the gas to be analyzed absorbs a specific wavelength component of the infrared light. The higher the concentration of the specific gas component, the greater the amount of infrared light absorbed and the greater the amount of infrared light attenuation.

[0034] The gas to be analyzed may contain an interference gas component, such as moisture (H2O), whose wavelength region of infrared light absorbed overlaps with the wavelength region of infrared light absorbed by a specific gas component. In this case, when infrared light passes through the cylindrical body 40, the interference gas component contained in the gas to be analyzed also absorbs the infrared light. When interference gas components are contained, strictly speaking, the attenuation of the infrared light transmitted through the cylindrical body 40 of the cell 4 indicates the concentration of the specific gas component and the total interference gas components. An example in which interference gas components are contained in the gas to be analyzed will be described below.

[0035] Each of the detectors 5 and 6 is a pneumatic type detector. A pneumatic type detector is a thermal type detector that detects the intensity of infrared rays. A pneumatic detector has the following features: Gas containing specific gas components is sealed inside. When the gas absorbs infrared rays, the gas expands and the gas 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 placed inside the pneumatic detector, or a change in the flow rate of the gas flowing inside the pneumatic detector. Detectors 5 and 6 are detectors that detect the intensity of infrared rays based on the gas flow rate.

[0036] Specifically, the detector 5 has a cylindrical block 50 with both end faces open. One end face of the block 50 faces the cell 4. The other end face of the block 50 faces the detector 6. A first transmission window 51 that transmits infrared light is fitted into the opening of the end face of the block 50 on the cell 4 side. A second transmission window 52 that transmits infrared light is fitted in the middle of the block 50. A third transmission window 53 that transmits infrared light is fitted into the opening of the end face of the block 50 on the detector 6 side. The shape of the cylindrical block 50 is, for example, a rectangular prism with a cylindrical cavity provided inside, as shown in the drawings (e.g., FIG. 6). However, the shape of the block 50 is not limited to this shape, and may be a shape other than a rectangular prism with a cylindrical cavity provided inside.

[0037] A first gas chamber 54 is formed by the block 50, the first transmission window 51, and the second transmission window 52. A second gas chamber 55 is formed by the block 50, the second transmission window 52, ​​and the third transmission window 53. The first gas chamber 54 and the second gas chamber 55 are each filled with a gas containing a specific gas component. The gases contained in the first gas chamber 54 and the second gas chamber 55 have substantially the same concentration of the specific gas component. The gas is sealed in the block 50. As described above, the specific gas component is an acidic gas component, for example, nitric oxide.

[0038] A communication passage 50a that connects the first gas chamber 54 and the second gas chamber 55 is provided on the side wall of the block 50. A flow sensor 56 that detects the flow rate of gas flowing through the communication passage 50a is disposed in the middle of the communication passage 50a. The gas flowing through the communication passage 50a passes through the flow sensor 56.

[0039] The infrared light transmitted through the cylindrical body 40 of the cell 4 enters the first gas chamber 54 through the first transmission window 51, and the infrared light transmitted through the first gas chamber 54 enters the second gas chamber 55 through the second transmission window 52. The infrared light transmitted through the second gas chamber 55 enters the detector 6 through the third transmission window 53. As described above, the infrared light transmitted through the cylindrical body 40 of the cell 4 passes through the first gas chamber 54. The infrared light transmitted through the first gas chamber 54 passes through the second gas chamber 55. The infrared light transmitted through the second gas chamber 55 enters the detector 6.

[0040] When infrared light passes through the first gas chamber 54, a specific gas component contained in the gas filled in the first gas chamber 54 absorbs a specific wavelength component of the infrared light. This causes the gas filled in the first gas chamber 54 to expand. Similarly, when infrared light passes through the second gas chamber 55, a specific gas component contained in the gas filled in the second gas chamber 55 absorbs a specific wavelength component of the infrared light. This causes the gas filled in the second gas chamber 55 to expand. The greater the amount of infrared light absorbed, the greater the expansion of the gas filled in the first gas chamber 54 and the second gas chamber 55. Most of the specific wavelength component of infrared light incident on the detector 5 from the cell 4 is absorbed in the first gas chamber 54, and the amount of infrared light absorbed by the gas filled in the second gas chamber 55 is small.

[0041] When infrared light passes through the detector 5, the gas in the first gas chamber 54 expands more than the gas in the second gas chamber 55, so the gas flows from the first gas chamber 54 through the communication path 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 the specific wavelength component absorbed 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 gas in the second gas chamber 55 is large. As a result, the stronger the intensity of the specific wavelength component of the infrared light incident on the detector 5, the greater the flow rate of the gas flowing through the communication path 50a.

[0042] As described above, the flow sensor 56 detects the flow rate of the gas flowing through the communication path 50a. Furthermore, the higher the concentration of the specific gas component and the total interference gas components contained in the gas to be analyzed, the greater the amount of the specific wavelength component of infrared light absorbed in the cell 4, and therefore the weaker the intensity of the specific wavelength component of infrared light incident on the detector 5. The weaker the intensity of the specific wavelength component of infrared light incident on the detector 5, the smaller the flow rate of the gas flowing through the communication path 50a. Detecting the flow rate of the gas flowing through the communication path 50a corresponds to detecting the intensity of the specific wavelength component of infrared light incident on the detector 5.

[0043] The flow sensor 56 detects the flow rate of the gas during the period when the infrared light emitted by the light source 2 is incident on the cell 4. When the chopper 3 blocks the infrared light, the gases filling the first gas chamber 54 and the second gas chamber 55 release heat. As a result, the state of these gases contracts and returns to the state before the infrared light was incident on the detector 5.

[0044] The detector 6 is configured similarly to the detector 5. The detector 6 has a cylindrical block 60, a first transmission window 61, a second transmission window 62, a third transmission window 63, and a flow sensor 66. The block 60, the first transmission window 61, the second transmission window 62, the third transmission window 63, and the flow sensor 66 correspond to the block 50, the first transmission window 51, the second transmission window 52, ​​the third transmission window 53, and the flow sensor 56 of the detector 5, respectively. As in the detector 5, a first gas chamber 64 is formed by the block 60, the first transmission window 61, and the second transmission window 62, and a second gas chamber 65 is formed by the block 60, the second transmission window 62, and the third transmission window 63.

[0045] The first gas chamber 64 and the second gas chamber 6 5 is , is filled with a gas containing a specific gas component. A communication passage 60a that connects the first gas chamber 64 and the second gas chamber 65 is provided in the side wall of the block 60. A flow sensor 66 that detects the flow rate of the gas flowing through the communication passage 60a is disposed midway through the communication passage 60a. The structure and operation 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.

[0046] The infrared light that has passed through the second gas chamber 55 of the detector 5 is incident on the first gas chamber 64 through the first transmission window 61 of the detector 6 and passes through the first gas chamber 64. The infrared light that has passed through the first gas chamber 64 is incident on the second gas chamber 65 through the second transmission window 62. 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.

[0047] In the detector 5, most of the specific wavelength components of the infrared light are absorbed by the specific gas components. Therefore, the intensity of the specific wavelength components of the infrared light transmitted through the detector 5 is low. Therefore, most of the wavelength components of the infrared light absorbed by the gas filled in the first gas chamber 64 and the second gas chamber 65 of the detector 6 are wavelength components absorbed by the interference gas components. As a result, the higher the concentration of the interference gas components contained in the gas to be analyzed, the weaker the intensity of the infrared light incident on the detector 6 and the lower the gas flow rate detected by the flow sensor 66.

[0048] 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 is higher 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. The proportion of the specific gas component in the gas filled in the first gas chamber 64 and the second gas chamber 65 of the detector 6 is, for example, 100%. In this case, the proportion of the specific gas component in the gas filled in the first gas chamber 54 and the second gas chamber 55 of the detector 5 is, for example, 10% to 20%, which is less than 100%.

[0049] The intensity of a particular wavelength component of the infrared light transmitted through the detector 5 is weak. However, as described above, the concentration of a particular gas component contained in the gas filled in the first gas chamber 64 and the second gas chamber 65 of the detector 6 is high, so that a large amount of infrared light is absorbed in the first gas chamber 64 and the second gas chamber 65. Therefore, the flow sensor 66 can easily detect the flow rate of the gas flowing through the communication passage 60a.

[0050] 2 is a block diagram showing the configuration of a gas analyzer 7 using the gas analyzer 1. As described above, the gas analyzer 1 includes the light source 2, the chopper 3, the cell 4, and the detectors 5 and 6. The gas analyzer 7 includes the gas analyzer 1 and a concentration calculation unit 70. The concentration calculation unit 70 has two amplifiers 70a and 70b, A / D conversion units 70c and 70d, a display unit 70e, a memory 70f, and a control unit 70g.

[0051] The detectors 5 and 6 are connected to amplifiers 70a and 70b, respectively. The amplifiers 70a and 70b are further connected to A / D converters 70c and 70d, respectively. The A / D converters 70c and 70d, the display unit 70e, the memory 70f, and the control unit 70g are connected to an internal bus 70h.

[0052] When the flow sensor 56 of the detector 5 and the flow sensor 66 of the detector 6 detect the flow rate of gas, they output analog flow signals indicating the detected flow rate of gas to the amplifiers 70a and 70b. The amplifiers 70a and 70b amplify the amplitude of the analog flow signals input from the detectors 5 and 6. The amplifiers 70a and 70b output the amplified analog flow signals to the A / D converters 70c and 70d. The A / D converters 70c and 70d convert the analog flow signals input from the amplifiers 70a and 70b into digital flow signals. The control unit 70g reads out the digital flow signals from the A / D converters 70c and 70d. The display unit 70e has a display panel and displays various values ​​according to instructions from the control unit 70g.

[0053] The memory 70f stores a computer program (not shown). The control unit 70g has a processing element that executes processing, such as a CPU (Central Processing Unit). The control unit 70g executes the computer program stored in the memory 70f to execute a concentration calculation process that calculates the concentration of a specific gas component contained in the gas to be analyzed.

[0054] In the concentration calculation process, the control unit 70g calculates the concentration of the specific gas component and the total interference gas component contained in the gas to be analyzed based on the flow rate of the gas indicated 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 total interference gas component based on the difference between the flow rate of the gas indicated by the flow rate signal input from the flow sensor 56 when the zero gas is flowing in the cylindrical body 40 of the cell 4 and the flow rate of the gas indicated by the flow rate signal input from the flow sensor 56 when the gas to be analyzed is flowing in the cylindrical body 40. The zero gas is a gas composed of a gas component that does not absorb infrared light, for example, nitrogen (N2). Therefore, even if infrared light passes through the zero gas, the zero gas does not absorb the infrared light.

[0055] The control unit 70g calculates the concentration of an interference gas component that has absorbed a specific wavelength component of infrared light, based on the gas flow rate indicated by the flow rate signal input from the flow sensor 66 of the detector 6. Specifically, the concentration calculation unit 70 calculates the concentration of the interference gas component based on the difference between the gas flow rate indicated by the flow rate signal input from the flow sensor 66 when zero gas is flowing inside the cylindrical body 40 of the cell 4 and the gas flow rate indicated by the flow rate signal input from the flow sensor 66 when the gas to be analyzed is flowing inside the cylindrical body 40.

[0056] As described above, the control unit 70g calculates the concentrations of the specific gas component and the interference gas component contained in the gas to be analyzed, and the concentration of the interference gas component contained in the gas to be analyzed. The control unit 70g accurately calculates the concentration of the specific gas component contained in the gas to be analyzed based on the two calculated concentrations. This allows the concentration of the specific gas component to be analyzed. The control unit 70g causes the display unit 70e to display the calculated concentration of the specific gas component. This allows the user to check the concentration of the specific gas component.

[0057] FIG. 3 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 depending on the temperature of the thin-film resistor Rs1. Similarly, the resistance value of the thin-film resistor Rs2 varies depending on the temperature of the thin-film resistor Rs2. The thin-film resistors Rs1 and Rs2 are the same type, and are manufactured using materials such as platinum or nickel. When a 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 acts in the same way as the thin-film resistor Rs1.

[0058] 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 each 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 a first divided voltage obtained by dividing the output voltage to the amplifier 70a of the concentration calculation unit 70 as a flow rate signal. Similarly, the fixed resistor R2 and the thin film resistor Rs2 divide the output voltage of the DC power supply E, and output a second divided voltage obtained by dividing the output voltage to the amplifier 70a of the concentration calculation unit 70 as a flow rate signal. The first divided voltage is higher as the resistance value of the thin film resistor Rs1 is larger, that is, as the temperature of the thin film resistor Rs1 is higher. 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.

[0059] The thin film resistors Rs1 and Rs2 are exposed to the communication path 50a. The thin film resistor Rs1 is disposed on the first gas chamber 54 side of the thin film resistor Rs2. The two thin film resistors Rs1 and Rs2 are in close proximity to each other. When a current flows from the DC power source E to each of the thin film resistors Rs1 and Rs2, the thin film resistors Rs1 and Rs2 generate heat. The thin film resistors Rs1 and Rs2 dissipate heat. When gas is not flowing through the communication path 50a, the amount of heat generated and the amount of heat dissipated are the same, and the temperatures of the thin film resistors Rs1 and Rs2 converge to a constant temperature.

[0060] When gas flows through the communication path 50a, the gas absorbs heat from the thin-film resistor Rs1. This causes the temperature of the thin-film resistor Rs1 to decrease. The greater the flow rate of gas through the communication path 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 path 50a, i.e., the stronger the intensity of a specific wavelength component of the infrared light incident on the detector 5, the lower the first divided voltage.

[0061] When the gas absorbs heat from the thin-film resistor Rs1, the temperature of the gas passing through the thin-film resistor Rs1 rises. The gas that absorbs heat from the thin-film resistor Rs1 passes through the thin-film resistor Rs2 that is 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 absorbing heat from the thin-film resistor Rs1. The greater the flow rate of the gas flowing through the communication path 50a, the higher the temperature of the thin-film resistor Rs2 rises to. 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 the gas flowing through the communication path 50a, i.e., the stronger the intensity of a specific wavelength component of the infrared light incident on the detector 5, the higher the second divided voltage.

[0062] As described above, the flow sensor 56 detects the flow rate of the gas flowing through the communication path 50a, and outputs the first divided voltage and the second divided voltage indicating the detected flow rate of the gas as flow signals to the amplifier 70a of the concentration calculation unit 70. The amplifier 70a amplifies the amplitude of each of the two flow signals input from the flow sensor 56, and outputs each of the two flow signals with amplified amplitudes to the A / D conversion unit 70c. The A / D conversion unit 70c converts each of the two analog flow signals into a digital flow signal.

[0063] As described above, the configuration and operation 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 the gas flowing through the communication path 60a, and outputs a first divided voltage and a second divided voltage indicating the detected flow rate of the gas as flow signals to the amplifier 70b of the concentration calculation unit 70. The amplifier 70b amplifies the amplitude of each of the two flow signals input from the flow sensor 66, and outputs each of the two flow signals with amplified amplitudes to the A / D conversion unit 70d. The A / D conversion unit 70d converts each of the two analog flow signals into a digital flow signal.

[0064] The following describes in detail the configuration of the detector 5. As described above, the configuration of the detector 6 is similar to the configuration of the detector 5. Therefore, a detailed description of the configuration of the detector 6 will be omitted.

[0065] FIG. 4 is a cross-sectional view of the detector 5 taken along the line AA in FIG. 1. As shown in FIG. 4, openings 50b and 50c used for discharging and injecting gas are provided on the outer surface of a 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 member 57 is bonded to the periphery of the opening 50b on the side wall of the block 50. The sealing member 57 covers the opening 50b to seal it. A second passage 50e connecting the opening 50c to the second gas chamber 55 is further provided on the side wall of the block 50. A sealing member 58 is bonded to the periphery of the opening 50c on the side wall of the block 50. The sealing member 58 covers the opening 50c to seal it.

[0066] FIG. 5 is an explanatory diagram of a process of sealing gas in the detector 5. Before sealing gas in the detector 5, the sealing members 57 and 58 are each cylindrical with both ends open, and are bonded to the periphery of the openings 50b and 50c in the side wall of the block 50. The through holes of the sealing members 57 and 58 communicate with the openings 50b and 50c. The sealing members 57 and 58 are each made of aluminum or copper, and are easily deformed by an external force. The sealing member 57 is cut in a direction intersecting the axial direction, for example, in the direction indicated by the arrow in FIG. 5. As a result, as shown in FIG. 4, the through hole of the sealing member 57 is blocked, and the sealing member 57 seals the opening 50b. Similarly, the sealing member 58 is cut in a direction intersecting the axial direction. As shown in FIG. 4, the through hole of the sealing member 58 is blocked, and the sealing member 58 seals the opening 50c.

[0067] When gas is sealed in the detector 5, the gas in the first gas chamber 54 and the second gas chamber 55 is sucked out from the through holes of the sealing members 57 and 58 via the first passage 50d and the second passage 50e by a vacuum pump or the like. As a result, the first gas chamber 54 and the second gas chamber 55 are in a vacuum state. With the first gas chamber 54 and the second gas chamber 55 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 member 57, and a gas containing a specific gas component is injected into the second gas chamber 55 from the opening of the sealing member 58. As a result, the first gas chamber 54 and the second gas chamber 55 are filled with a gas containing a specific gas component. After the gas is injected, the sealing members 57 and 58 are cut as described above. As a result, the sealing members 57 and 58 are deformed and the through holes are blocked. As a result, the openings 50b and 50c are sealed.

[0068] Fig. 6 is a cross-sectional view of the detector 5 taken along the line BB in Fig. 1. As shown in Fig. 6, 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 path 50a. The state of the sealing member 57 shown in Fig. 6 is the state after cutting, and the sealing member 57 seals the opening 50b.

[0069] The detector 5 further has a box-shaped drying container 8 containing an acidic desiccant. Examples of acidic desiccant include diphosphorus pentoxide, calcium chloride, and magnesium sulfate. The side wall of the block 50 is further provided with an insertion hole 50f into which the drying container 8 is inserted. When the drying container 8 is inserted into the insertion hole 50f, the opening of the insertion hole 50f provided on the outer surface of the block 50 is sealed by a spherical sealing member 59. The sealing member 59 is made of, for example, metal. The insertion hole 50f and the sealing member 59 form a storage chamber in which the drying container 8 is stored.

[0070] A first passage opening 50g of the first passage 50d is provided on the bottom surface of the insertion hole 50f. The first passage 50d is branched into two passages connected to the opening 50b. 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 by the first passage 50d.

[0071] The chamber connected to the storage chamber formed by the insertion hole 50f and the sealing member 59 is not limited to the first gas chamber 54. As a first example, the second passage opening of the second passage 50e may be provided on the bottom surface of the insertion hole 50f. In this case, the second passage 50e is branched into two passages connected to the opening 50c, one of the two branched passages is connected to the first gas chamber 54, and the other of the two branched passages is connected to the second passage opening. As a second example, the passage opening provided on the bottom surface of the insertion hole 50f may be connected to the communication passage 50a by a passage. In this case, the storage chamber is connected to the first gas chamber 54 and the second gas chamber 55 by the passage and the communication passage 50a. In the following, an example in which the storage chamber is connected to the first gas chamber 54 will be described.

[0072] Fig. 7 is a partial cross-sectional view of the detector 5. Fig. 7 shows a part of the cross section shown in Fig. 6. In the drying container 8, a lid 81 is fitted into an opening of a housing 80 having one open side. The drying container 8 is placed in the storage chamber so that the bottom surface of the housing 80 is the surface closest to the first passage port 50g provided in the bottom wall of the insertion hole 50f, that is, so that the bottom wall of the housing 80 is located on the right side in Figs. 6 and 7. A desiccant is stored in the housing 80.

[0073] FIG. 8 is an explanatory diagram of the lid 81 of the drying container 8. The upper side of FIG. 8 shows a plan view of the lid 81. The lower side of FIG. 8 shows a side view of the lid 81. As shown in FIG. 8, the lid 81 is provided with a notch 81a. As shown in FIG. 7, the notch 81a penetrates the housing 80 in the axial direction and extends from the edge of the lid 81 to the center of the lid 81. In the drying container 8, a gas inlet / outlet 82 is formed by the housing 80 and the notch 81a.

[0074] As shown in FIG. 7, 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 / outlet 82 of the drying container 8 is connected to the first passage 50d through the notch 81a, the first gap, and the second gap. The gas filled in 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 from the inlet / outlet 82. The gas filled in the second gas chamber 55 flows through the communication path 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 from the inlet / outlet 82. The desiccant in the drying container 8 absorbs moisture from the gas that has entered the drying container 8. The gas that has absorbed moisture exits the drying container 8 from the inlet / outlet 82. The gas exiting the inlet / outlet 82 flows through the notch 81a, the first gap, the second gap, and the first passage 50d, in that order, and returns to the first gas chamber 54. The gas exiting the inlet / 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 passage 50a, in that order, and returns to the second gas chamber 55.

[0075] As described above, in the detector 5, the gas filled in the first gas chamber 54 and the second gas chamber 55 enters the drying container 8, and the moisture contained in the gas is absorbed by the desiccant. Therefore, the first gas chamber 54 and the second gas chamber 55 are dry. Therefore, in the detector 5, infrared light is not absorbed by moisture.

[0076] 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, the gas in the first gas chamber 54 and the second gas chamber 55 are sucked to the outside through the first passage 50d and the second passage 50e by a vacuum pump or the like before sealing the openings 50b and 50c. This makes the state inside the block 50 a vacuum state. Then, the gas containing the specific gas component is sealed in the block 50, and the air pressure inside the block 50 returns to atmospheric pressure. After sealing the gas, the openings 50b and 50c are sealed. Note that the gas in the sealed block 50 may contain a trace amount of moisture contained in the gas of the specific gas component, or a trace amount of moisture contained in the sealing equipment, adhesive, etc.

[0077] In the case where a desiccant is accommodated in the accommodation chamber formed by the insertion hole 50f and the sealing member 59, if the desiccant has deliquescence, the desiccant absorbs moisture and part of the desiccant changes to liquid. The gas is filled into the detector 5 after the detector 5 is evacuated while the desiccant is accommodated in the accommodation chamber formed by the insertion hole 50f and the sealing member 59. If the desiccant is deliquesced in the process of evacuating the detector 5, the deliquesced liquid may scatter. If the liquid scatters, the deliquesced liquid may 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 clouding. When infrared light passes through a clouded transmission window, the intensity of the infrared light is attenuated.

[0078] In this case, the flow rate of the gas detected by the flow sensor 56 does not accurately indicate the intensity of a specific wavelength component of the infrared light incident on the first gas chamber 54. However, in the drying container 8, the gas inlet / outlet 82 is provided at a location different from the location facing the first passage opening 50g of the first passage 50d, specifically, in the lid 81 of the drying container 8 on the opposite side of the bottom wall of the housing 80 in the drying container 8. For this reason, even if liquid is splashed, the splashed liquid is unlikely to enter the first gas chamber 54 or the second gas chamber 55, and the first transmission window 51, the second transmission window 52, ​​or the third transmission window 53 are unlikely to become cloudy. As a result, there is almost no attenuation of the infrared light that occurs when the infrared light passes through the first transmission window 51, the second transmission window 52, ​​or the third transmission window 53. The surface of the drying container 8 facing the bottom surface of the housing 80 is the surface of the lid 81.

[0079] In the drying container 8, the location where the gas inlet / outlet 82 is provided is not limited to the lid 81 of the drying container 8, and may be, for example, a side wall of the housing 80. As shown in Fig. 7, the bottom wall of the housing 80 of the drying container 8 is flat. However, the bottom wall of the housing 80 may be curved.

[0080] In addition, the specific gas component is an acidic gas component, and an acidic substance is used as the desiccant, so that 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. As described above, the detector 6 has the same configuration as the detector 5. Therefore, the detector 6 has the same effects as the detector 5.

[0081] Furthermore, when the intensity of the infrared light incident on the detector 6 is sufficiently strong, the concentration of a specific gas component contained in the gas filled in the first gas chamber 64 and the second gas chamber 65 of the detector 6 may be lower than the concentration of a specific gas component contained in the gas filled in the first gas chamber 54 and the second gas chamber 55 of the detector 5.

[0082] Furthermore, when the gas to be analyzed does not contain any interfering gas components, the control unit 70g of the concentration calculation unit 70 can calculate the concentration of the specific gas component based on the gas flow rate indicated by the flow rate signal input from the flow sensor 56 of the detector 5. In this case, the configuration of the gas analyzer 1 may be such that the detector 6 is omitted. Furthermore, the specific gas component is not limited to an acidic gas component, and may be an alkaline gas component. In this case, an alkaline substance is used as the desiccant.

[0083] (Embodiment 2) FIG. 9 is a cross-sectional view showing an outline of a gas analyzer 1a according to the second embodiment. The following describes the differences between embodiment 2 and embodiment 1. Except for the configuration described below, the other configurations are common to embodiment 1. For this reason, components common to embodiment 1 are given the same reference numerals as embodiment 1, and descriptions thereof will be omitted.

[0084] One type of light source used in a conventional gas analyzer equipped with a detector that detects the intensity of infrared light is a light source in which a light-emitting element that emits infrared light is housed in a box-shaped reflector with one side open. For example, the light-emitting element is disposed on the bottom surface of the reflector, and part of the infrared light emitted by the light-emitting element is reflected by the inner surface of the reflector and propagates toward the cell. When the light-emitting element emits light, heat is generated in the light-emitting element. The generated heat is conducted to the reflector, which dissipates the heat. A blower blows air toward the reflector. This allows the reflector to dissipate heat efficiently.

[0085] However, when the wind blown by the blower enters the reflector, the temperature of the light-emitting element fluctuates due to the wind. The intensity of the infrared light emitted by the light-emitting element fluctuates according to the temperature of the light-emitting element. Therefore, when the temperature of the light-emitting element fluctuates due to the wind, the intensity of the infrared light emitted by the light source is not stable. In this case, the concentration of a specific gas component contained in the gas to be analyzed cannot be properly calculated. An object of the second embodiment is to provide a gas analyzer in which wind does not enter the reflector.

[0086] The gas analyzer 1a in the second embodiment includes a cell 4 and detectors 5 and 6, similar to the gas analyzer 1 in the first embodiment. The gas analyzer 1a in the second embodiment includes a light source 9 instead of the light source 2. In the gas analyzer 1a, a blower F that blows air to the light source 9 is disposed near the light source 9.

[0087] A power source (not shown) supplies power to the light source 9 via a switch (not shown). When the switch is on, the light source 9 emits infrared light with a constant intensity toward the cell 4. When the switch is off, the light source 9 stops emitting infrared light. The switch is alternately switched on and off. As a result, the infrared light emitted by the light source 9 is intermittently incident on the cell 4, similar to the infrared light emitted by the light source 2 in the first embodiment. As in the first embodiment, the gas analyzer 1a may have a configuration in which the detector 6 is omitted.

[0088] FIG. 10 is an explanatory diagram of the light source 9. FIG. 10 shows a cross section, a side surface, and a plan view of the light source 9. In the light source 9, a bottom wall 91a of a reflector 91 having a box shape with one side open is provided on the plate surface of a rectangular plate-like substrate 90. The bottom wall 91a is circular. In the reflector 91, a side wall 91b extends obliquely from the peripheral portion of the bottom wall 91a and spreads outward from the bottom wall 91a. Therefore, the area of ​​the opening of the reflector 91 is larger than the area of ​​the bottom wall 91a.

[0089] 10, in the light source 9, a light emitting element 92 that emits infrared light is disposed in the center of a bottom wall 91a and is housed in a reflector 91. The light emitting element 92 is, for example, a filament. A part of the infrared light emitted by the light emitting element 92 propagates toward the open surface of the reflector 91, i.e., toward the cell 4. The other part of the infrared light emitted by the light emitting element 92 is reflected by the inner surface of the bottom wall 91a or the side wall 91b and propagates toward the open surface of the reflector 91.

[0090] An elastic, annular contact member 93 is disposed on an end face of a side wall 91b of the reflector 91. The contact member 93 is a so-called O-ring. As shown in Figs. 9 and 10, in the light source 9, a cylindrical cover 94 covers the outer surface of the side wall 91b. The cover 94 is disposed on the plate surface of the substrate 90. As shown in Fig. 9, the cover 94 protrudes toward the cell 4 side beyond the contact member 93.

[0091] 9, in the cell 4, a part of the transmission window 41 is exposed to the outside from the end face of the cylindrical body 40 on the light source 9 side. The exposed part of the transmission window 41 is fitted into a cover 94 of the light source 9. The transmission window 41 is pressed toward the bottom wall 91a of the reflector 91 until the end face of the cylindrical body 40 on the light source 9 side comes into contact with the end face of the cover 94. As a result, the contact member 93 is in close contact with the peripheral portion of the opening of the reflector 91 and the peripheral portion of the transmission window 41.

[0092] As shown in Fig. 10, the cover 94 is provided with a plurality of openings 94a penetrating inward and outward directions. The reflector 91 is made of a material with high thermal conductivity, such as metal. The power source supplies power to the light-emitting element 92 via the switch. When the switch is on, the power source supplies power to the light-emitting element 92, and the light-emitting element 92 emits infrared light. When the switch is off, the light-emitting element 92 stops emitting light.

[0093] When the light-emitting element 92 emits infrared light, the light-emitting element 92 generates heat. The heat generated by the light-emitting element 92 is conducted to the reflector 91, which dissipates the heat. The fan F blows air toward the reflector 91. The air blown by the fan F passes through a plurality of openings 94a in the cover 94 and strikes a side wall 91b of the reflector 91, and the air that strikes the side wall 91b passes through the plurality of openings 94a and exits the light source 9 to the outside. For this reason, the reflector 91 efficiently dissipates heat, and a rise in temperature of the light-emitting element 92 is suppressed.

[0094] As described above, the contact member 93 is in close contact with the reflector 91 and the transmission window 41 of the cell 4. For this reason, the wind sent by the blower F does not enter the reflector 91. If the wind sent by the blower F enters the reflector 91, the temperature of the light-emitting element 92 in the reflector 91 will fluctuate, and the intensity of the infrared light emitted from the light source 9 to the cell 4 will become unstable, making it impossible to properly calculate the concentration of a specific gas component contained in the gas to be analyzed.

[0095] FIG. 11 is a graph 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 the specific gas component based on the flow rate of the gas indicated by the flow rate signal input from the flow sensors 56, 66 of the detectors 5, 6. FIG. 10 shows the transition of two concentrations of the specific gas component calculated when zero gas flows in the cylindrical body 40 of the cell 4. One concentration is a concentration calculated in a gas analyzer in which the contact member 93 is not used, and is shown by a thin solid line. The other concentration is a concentration calculated by the concentration calculation unit 70 of the gas analyzer 1a, and is shown by a thick solid line. The horizontal axis shows the transition of these concentrations. Since the specific gas component does not exist in the cylindrical body 40, the concentration of the specific gas component is actually zero.

[0096] 11, when the contact member 93 is not used, the calculated concentration fluctuates greatly even though the actual concentration is zero. It can be seen 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 in which the contact member 93 is used hardly fluctuates, and the range of concentration fluctuation is also small. It can be seen that the error in the calculated concentration is small.

[0097] As described above, in the gas analyzer 1a in the second embodiment, there is no gap between the reflector 91 of the light source 9 and the transmission window 41 of the cell 4, so the wind sent 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 calculates an accurate concentration. The configurations of the detectors 5 and 6 in the second embodiment are similar to those in the first embodiment. Therefore, the detectors 5 and 6 in the second embodiment provide the same effects as those in the first embodiment.

[0098] In the second embodiment, the method of generating intermittent infrared light is not limited to the method of alternately repeating switching of a switch between on and off. For example, as in the first embodiment, intermittent infrared light may be generated using a chopper 3. In this method, when the chopper 3 rotates, the impeller of the chopper 3 passes between, for example, the cell 4 and the detector 5. In the first embodiment, the method of generating intermittent infrared light is not limited to the method of rotating the chopper 3. For example, as in the second embodiment, the method may be a method of alternately repeating switching of a switch arranged on a path through which a power source supplies power to the light source 2. In the first embodiment, the light source 2 may be a device that emits infrared light. Therefore, the configuration of the light source 2 in the first embodiment may be the same as the configuration of the light source 9, or may be different from the configuration of the light source 9.

[0099] (Embodiment 3) In the second embodiment, the detectors 5 and 6 filled with a gas containing a specific gas component are used as detectors for detecting the intensity of incident infrared light. However, the detector for detecting the intensity of infrared light is not limited to the detector filled with a gas. The following describes the differences between the third embodiment and the second embodiment. Except for the configuration described below, the other configurations are common to the second embodiment. Therefore, the components common to the second embodiment are given the same reference numerals as the second embodiment, and the description thereof will be omitted.

[0100] FIG. 12 is a cross-sectional view showing an outline of a gas analyzer 1b in the third embodiment. In the gas analyzer 1b, the intensity of a specific wavelength component of the infrared light transmitted through the cylindrical body 40 of the cell 4 is detected by a detector D. In the detector D, the infrared light transmitted through the cylindrical body 40 of the cell 4 passes through a plurality of filters. Only predetermined wavelength components of the infrared light are transmitted through the filters. The wavelength components transmitted through the plurality of filters are different from each other. The intensities of the plurality of infrared lights transmitted through each of the plurality of filters, i.e., the intensities of the plurality of wavelength components related to the infrared light transmitted through the cylindrical body 40 of the cell 4, are detected by a plurality of light receiving elements.

[0101] The detector D detects the intensity of a specific wavelength component and the intensity of a reference wavelength component that is not absorbed in the cylindrical body 40 of the cell 4 for the infrared light transmitted through the cylindrical body 40 of the cell 4. In the gas analyzer 7 using the gas analyzer 1b, the detector D is connected to an amplifier 70a of the concentration calculation unit 70. The detector D outputs to the amplifier 70a of the concentration calculation unit 70 a first analog intensity signal indicating the intensity of the detected specific wavelength component and a second analog intensity signal indicating the intensity of the detected reference wavelength component.

[0102] The amplifier 70a amplifies the amplitude of the first intensity signal and the second intensity signal, and outputs the amplified analog first intensity signal and second intensity signal to the A / D converter 70c. The A / D converter 70c converts the analog first intensity signal into a digital 1 The control unit 70g converts the first intensity signal and the second intensity signal from the A / D conversion unit 70c into a digital intensity signal, and converts the analog first intensity signal into a digital second intensity signal. The control unit 70g reads out the first intensity signal and the second intensity signal from the A / D conversion unit 70c. In the third embodiment, the concentration calculation unit 70 does not need to have the amplifier 70b and the A / D conversion unit 70d.

[0103] In 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 gas to be analyzed 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. In this way, the concentration of the specific gas component is analyzed.

[0104] In the gas analyzer 1b configured as above, when the wind sent by the blower F enters the reflector 91, the temperature of the light emitting element 92 fluctuates, and the intensity of the infrared light emitted by the light source 9 becomes unstable. However, since the light source 9 in the third embodiment is configured similarly to the second embodiment, there is no gap between the reflector 91 of the light source 9 and the transmission window 41 of the cell 4. Therefore, the wind sent by the blower F does not enter the reflector 91, 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 becomes stable, and an accurate concentration is calculated by the control unit 70g of the concentration calculation unit 70. Also, as in the second embodiment, in the light source 9, the reflector 91 efficiently dissipates heat, and the temperature rise of the light emitting element 92 is suppressed.

[0105] In the third embodiment, the number of specific gas components whose concentrations are detected is not limited to one, and may be, for example, two or more. In this case, the 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 the one specific gas component using the intensity of the one specific wavelength component and the intensity of the reference wavelength component. In the same manner, the control unit 70g calculates the concentrations of the other specific gas components. When the number of specific gas components is three, examples of the three specific gas components include carbon dioxide, carbon monoxide, and hydrocarbons.

[0106] A gas analyzer according to one aspect of the second or third embodiment is a gas analyzer for analyzing the concentration of a specific gas component that is contained in a gas to be analyzed and absorbs a specific wavelength component of infrared light, the gas analyzer includes a light source that emits infrared light, a cell through which the gas to be analyzed flows and through which the infrared light emitted by the light source passes, and an intensity detector that detects the intensity of the specific wavelength component of the infrared light that passes through the cell, the cell having a transmission window through which the infrared light emitted by the light source passes, the light source having a light-emitting element that emits infrared light, a box-like body with one side open, housing the light-emitting element, a reflector that reflects the infrared light emitted by the light-emitting element, and an annular contact member that is in close contact with the periphery of the opening of the reflector and the periphery of the transmission window. In the second and third embodiments, the detectors 5 and D each function as the intensity detector.

[0107] A gas analyzer according to one aspect of embodiment 2 or embodiment 3 preferably includes a blower, the light source having a cylindrical covering body covering a side surface of the reflector, the covering body having a plurality of openings, and the blower blowing air toward the covering body.

[0108] The technical features (constituent elements) described in the first to third embodiments can be combined with each other, and by combining them, new technical features can be formed. The disclosed embodiments 1 to 3 are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0109] 1,1a Gas analyzer 2,9 light source 4 Cell 5,6 Detectors 8 Drying container 41 Transparent window 50a,60a connecting route 50d 1st aisle 50f Insertion hole (part of the containment chamber) 50g 1st aisle entrance 54,64 Gas Chamber No. 1 55,65 Gas Chamber No. 2 56,66 Flow sensor 59 Sealing material (part of the containment chamber) 82 Entrance / Exit 91 Reflector 92 Light emitting element 93 Adhesive Materials 94 Covering Body 94a Opening F Blower

Claims

1. In a detector for detecting the intensity of infrared light, a first gas chamber filled with a gas containing an acidic gas component and through which infrared light passes; a second gas chamber filled with a gas containing the gas component and through which the infrared light transmitted through the first gas chamber passes; a communication path connecting the first gas chamber and the second gas chamber; a flow sensor for detecting a flow rate of the gas flowing through the communication path; a storage chamber connected to the first gas chamber or the second gas chamber by a passage and configured to store a drying container containing an acidic desiccant; a gas inlet / outlet is provided in the drying container at a position different from a position facing a passage opening of the passage provided in the storage chamber, The doorway communicates with the passageway. Detector.

2. the gas component is nitric oxide; The desiccant is diphosphorus pentoxide, calcium chloride or magnesium sulfate.

2. The detector of claim 1.

3. In a detector for detecting the intensity of infrared light, a first gas chamber filled with gas and transparent to infrared light; a second gas chamber filled with gas and through which the infrared light transmitted through the first gas chamber passes; a communication path connecting the first gas chamber and the second gas chamber; a flow sensor for detecting a flow rate of the gas flowing through the communication path; a storage chamber connected to the first gas chamber or the second gas chamber by a passage and configured to store a drying container containing a desiccant; Equipped with a gas inlet / outlet is provided in the drying container at a position different from a position facing a passage opening of the passage provided in the storage chamber, The doorway communicates with the passageway. Detector.

4. 2. A gas analyzer for analyzing the concentration of a specific gas component that is contained in an analysis target gas and absorbs a specific wavelength component of infrared light, A detector according to any one of claims 1 to 3; A light source that emits infrared light; a cell through which the gas to be analyzed flows; Equipped with 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 is transmitted through the cell, The infrared light transmitted through the cell is transmitted through the first gas chamber of the detector, The concentration is calculated based on the flow rate detected by the flow sensor. Gas analyzers.

5. The number of detectors is two; The infrared light transmitted through the cell is transmitted through a first gas chamber of one of the detectors, The infrared light transmitted through the second gas chamber of the one detector is transmitted through the first gas chamber of the other detector, The concentration is calculated based on two flow rates detected by two flow sensors provided in the two detectors.

5. The gas analyzer of claim 4.

6. 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.

6. A gas analyzer according to claim 5.

7. the cell has a transmission window through which the infrared light emitted by the light source passes, The light source is A light emitting element that emits infrared light; a reflector having a box shape with one side open, housing the light emitting element, and reflecting infrared light emitted by the light emitting element; an annular contact member that is in close contact with a peripheral portion of the opening of the reflector and a peripheral portion of the transmission window; 7. A gas analyzer according to claim 4, further comprising:

8. Equipped with a blower, The light source has a cylindrical cover that covers a side surface of the reflector, The cover is provided with a plurality of openings, The blower blows air toward the covering body.

8. A gas analyzer according to claim 7.

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