JP6460249B2 - Calibration method for gas concentration detector and calibration aid for gas concentration detector - Google Patents

Description

  The present invention relates to a gas concentration detector calibration method and a gas concentration detector calibration aid.

  For example, JP 2006-126132 A (Patent Document 1) is cited as a document disclosing a calibration method for a gas concentration detector.

  The gas concentration detector disclosed in Patent Document 1 is installed in a duct, and is arranged in an outer tube provided with an introduction slit for introducing gas flowing in the duct, and the outer tube. A gas cell and a circuit board. The gas cell accommodates the light emitting element and the light receiving element therein and has a gas inlet for introducing the gas into the optical path between the light emitting element and the light receiving element. The circuit board processes a detection signal from the light receiving element.

  A calibration gas supply pipe inserted into the outer tube from the outside of the duct is connected to the gas cell. The end of the calibration gas supply pipe located outside the duct is connected to, for example, a cylinder supplied with inspection zero gas. When the gas concentration detector is calibrated, the calibration gas is introduced into the gas cell via the calibration gas supply pipe. Calibration of the gas concentration detector is automatically performed by satisfying a predetermined condition.

JP 2006-126132 A

  In Patent Document 1, it is assumed that calibration of the gas concentration detector is automatically performed without an operator. However, in order to perform calibration more reliably, an operator may be required to calibrate the gas concentration detector directly.

  Generally, when an operator calibrates a gas concentration detector, the operator brings a calibration gas production apparatus for producing a calibration gas to the site, and the calibration is performed as disclosed in Patent Document 1. The calibration gas production apparatus is connected to one end side of the gas supply pipe.

  For example, when a carbon dioxide gas detector is calibrated, calibration gas is produced by reducing carbon dioxide from the atmosphere. In this case, the calibration gas manufacturing apparatus includes a pump for sucking air, a drive unit for operating the pump, an absorbent for reducing carbon dioxide, and air for removing dust and the like contained in the air. Provide a filter.

  For this reason, the calibration gas production apparatus becomes large, and the weight increases, the size increases, and it is inconvenient to carry. Furthermore, with the configuration as described above, the calibration gas production apparatus becomes expensive, and it is difficult to prepare a plurality of gas calibration production apparatuses. For this reason, an operator must calibrate a plurality of gas concentration detectors installed in a building or the like in order using a single calibration gas manufacturing apparatus, which increases the labor required for the operator. It was inconvenient. Furthermore, when it is necessary to supply power to the drive unit and the battery is discharged, an outlet plug is required around the battery, and the area that can be calibrated may be limited.

  The present invention has been made in view of the above problems, and an object of the present invention is to manufacture a calibration gas without using electric power and to easily calibrate a gas concentration detector. A calibration method for a gas concentration detector and a calibration aid for the gas concentration detector are provided.

  A gas concentration detector calibration method according to the present invention includes an optical path member having an infrared optical path therein and a communication section for communicating the optical path with an external space, and an infrared irradiation element installed in the optical path And an infrared light receiving element, the measurement object gas introduced into the optical path through the communicating portion is irradiated with infrared rays using the infrared irradiation element, and the infrared light irradiated to the measurement object gas is converted into the infrared light receiving element. Is a calibration method for a non-dispersive infrared absorption type gas concentration detector that detects the concentration of a specific gas contained in the measurement target gas by receiving light at the absorber, and the absorbent capable of absorbing the specific gas and the above The cover member capable of containing the absorbent is communicated to the optical path through the communicating portion, and the absorbent is outside the optical path member by the cover member. And attaching to the gas concentration detector so as to be separated from the outside air, and maintaining the state in which the cover member and the absorbent are attached to the gas concentration detector. Reducing the concentration of the specific gas, and calibrating the gas concentration detector in a state where the concentration of the specific gas in the optical path is reduced.

  Here, “attaching to the gas concentration detector” means attaching to the gas concentration detector so as to support the gas concentration detector and the aspect directly attached to the gas concentration detector. It includes an aspect of being indirectly attached to the gas concentration detector such as being attached to the support member.

  In the gas concentration detector calibration method according to the present invention, the gas concentration detector is installed in a housing provided with an introduction port through which the measurement target gas is introduced from the outside. Preferably, the housing includes a first housing in which a maintenance opening is provided and the gas concentration detector is assembled, and a second housing that allows the maintenance opening to be opened and closed. In this case, the method for calibrating the gas concentration detector includes a step of opening the maintenance opening before the step of attaching the absorbent and the cover member to the gas concentration detector. It is preferable to further comprise.

  In the gas concentration detector calibration method according to the present invention, the gas concentration detector may further include a substrate portion on which the optical path member is mounted. The cover member may be constituted by a frame-shaped partition member having both ends opened, which is a separate member from the housing, and a part of the second housing. In this case, the step of attaching the absorbent and the cover member to the gas concentration detector includes bringing the opened end of the partition member into contact with the substrate portion, whereby the optical path member is formed by the partition member. Enclosing the inside of the first housing, and bringing the second housing into contact with the other open end of the partition member by closing the maintenance opening with the second housing. It is preferable to contain.

  In the gas concentration detector calibration method according to the present invention, as the partition member, a member provided with an elastically deformable seal at the one end and the other end opened of the partition member is used. Is preferred.

  A calibration aid for a gas concentration detector according to the present invention includes an optical path member having an infrared optical path therein and a communication portion for communicating the optical path with an external space, and an infrared irradiation element installed in the optical path And an infrared light receiving element, the measurement object gas introduced into the optical path through the communicating portion is irradiated with infrared rays using the infrared irradiation element, and the infrared light irradiated to the measurement object gas is converted into the infrared light receiving element. A calibration aid for a gas concentration detector for calibrating a non-dispersive infrared absorption type gas concentration detector that detects the concentration of a specific gas contained in the measurement target gas by receiving light at An absorbent capable of absorbing a specific gas; and a cover member capable of accommodating the absorbent, wherein the absorbent and the cover member are configured such that the absorbent passes through the communication portion and the optical path. With lead, as described above absorbent is partitioned with the outside air in the outside of the light path member by the cover member are configured to be attached to the gas concentration detector.

  In the auxiliary device for a gas concentration detector according to the present invention, the gas concentration detector is preferably installed in a housing provided with an introduction port through which the measurement target gas is introduced from the outside. In this case, the housing may include a first housing in which a maintenance opening is provided and the gas concentration detector is assembled, and a second housing that allows the maintenance opening to be opened and closed. preferable. Moreover, the said cover member may be comprised by the division member which consists of a member different from the said housing, and has the box shape which one end opened. In this case, in the open state in which the second housing is removed and the maintenance opening is opened, one end of the partition member contacts the first housing and covers the gas concentration detector. Thus, it may be configured to be attachable to the first housing.

  In the auxiliary device for a gas concentration detector according to the present invention, the gas concentration detector is preferably installed in a housing provided with an introduction port through which the measurement target gas is introduced from the outside. In this case, the housing may include a first housing in which a maintenance opening is provided and the gas concentration detector is assembled, and a second housing that allows the maintenance opening to be opened and closed. preferable. Moreover, the said cover member may be comprised from the member different from the said housing, and may be comprised by the division member which has the box shape which one end opened. In this case, the gas concentration detector may further include a substrate portion on which the optical path member is mounted, and the cover member has the maintenance opening opened after the second housing is removed. In the open state, one end of the partition member may be configured to be attachable to the substrate portion so as to contact the substrate portion and cover the optical path member.

  In the auxiliary device for a gas concentration detector according to the present invention, the gas concentration detector is preferably installed in a housing provided with an introduction port through which the measurement target gas is introduced from the outside. In this case, the housing may include a first housing in which a maintenance opening is provided and the gas concentration detector is assembled, and a second housing that allows the maintenance opening to be opened and closed. preferable. Moreover, the said cover member may be comprised from the member different from the said housing, and may be comprised by the division member which has the box shape which one end opened. The gas concentration detector may further include a substrate portion on which the optical path member is mounted. In this case, the cover member is configured so that one end of the partition member abuts on the optical path member and covers the communication portion in an opened state in which the second housing is removed and the maintenance opening is opened. You may be comprised so that attachment to the said optical path member is possible.

  In the gas concentration detector auxiliary tool according to the present invention, it is preferable that an elastically deformable seal portion is provided at the one end where the partition member having the box shape is opened.

  In the auxiliary device for a gas concentration detector according to the present invention, the gas concentration detector is preferably installed in a housing provided with an introduction port through which the measurement target gas is introduced from the outside. In this case, the housing may include a first housing in which a maintenance opening is provided and the gas concentration detector is assembled, and a second housing that allows the maintenance opening to be opened and closed. preferable. The cover member may be constituted by a frame-shaped partition member having both ends opened, which is a separate member from the housing, and a part of the second housing. In this case, when the second housing is removed and the maintenance opening is opened, the frame-shaped partition member abuts the open end of the frame-shaped partition member against the first housing. By making contact, the gas concentration detector may be configured to be able to surround. Further, the frame-shaped partition member may be configured so that the gas-concentration detector is surrounded by the frame-shaped partition member and the second housing closes the maintenance opening. The other end opened may be configured to be fixed by being sandwiched between the first housing and the second housing by contacting the second housing.

  In the auxiliary device for a gas concentration detector according to the present invention, the gas concentration detector is preferably installed in a housing provided with an introduction port through which the measurement target gas is introduced from the outside. In this case, the housing may include a first housing in which a maintenance opening is provided and the gas concentration detector is assembled, and a second housing that allows the maintenance opening to be opened and closed. preferable. The cover member may be configured by a frame-shaped partition member having both ends opened, which is a member different from the housing, and a part of the second housing. It may further include a substrate portion on which the optical path member is mounted. In this case, the frame-shaped partition member abuts the open end of the frame-shaped partition member against the substrate portion when the second housing is removed and the maintenance opening is opened. By doing so, the optical path member may be configured to be able to surround. Further, the frame-shaped partition member has an opening of the frame-shaped partition member in a closed state in which the optical path member is surrounded by the frame-shaped partition member and the second housing closes the maintenance opening. The other end thus brought into contact with the second housing may be configured to be sandwiched and fixed between the substrate portion and the second housing.

  In the auxiliary device for a gas concentration detector according to the present invention, the gas concentration detector is preferably installed in a housing provided with an introduction port through which the measurement target gas is introduced from the outside. In this case, the housing may include a first housing in which a maintenance opening is provided and the gas concentration detector is assembled, and a second housing that allows the maintenance opening to be opened and closed. preferable. The cover member may be configured by a frame-shaped partition member having both ends opened, which is a member different from the housing, and a part of the second housing. It may further include a substrate portion on which the optical path member is mounted. In this case, the frame-shaped partition member is in contact with the optical path member at an open end of the frame-shaped partition member when the second housing is removed and the maintenance opening is opened. By doing so, you may be comprised so that the said communication part can be enclosed. Further, the frame-shaped partition member has an opening of the frame-shaped partition member in a closed state in which the communication portion is surrounded by the frame-shaped partition member and the second housing closes the maintenance opening. The other end thus brought into contact with the second housing may be configured to be sandwiched and fixed between the optical path member and the second housing.

  In the gas concentration detector calibration aid according to the present invention, the one end and the other end opened of the frame-shaped partition member are provided with elastically deformable seal portions. preferable.

  According to the present invention, there is provided a calibration method for a gas concentration detector and a calibration aid for a gas concentration detector that can manufacture a calibration gas without using electric power and can easily calibrate the gas concentration detector. be able to.

1 is an exploded perspective view of a gas concentration detection device according to Embodiment 1. FIG. It is a schematic sectional drawing which shows the installation state which installed the gas concentration detection apparatus which concerns on Embodiment 1 in the duct. 1 is a schematic diagram of a gas concentration detector according to Embodiment 1. FIG. 2 is a circuit configuration diagram of a gas concentration detector according to Embodiment 1. FIG. It is a disassembled perspective view of the gas concentration detection apparatus which concerns on Embodiment 1, and the calibration assistance tool for gas concentration detectors. 3 is a flowchart of a gas concentration detector calibration method according to Embodiment 1. FIG. FIG. 6 is an exploded perspective view showing a process of surrounding an optical path member of the gas concentration detector according to Embodiment 1. FIG. 8 is a plan view showing a state after the step of surrounding the optical path member of the gas concentration detector according to Embodiment 1 with a partition member. FIG. 7 is an exploded perspective view showing a state after the step of putting an absorbent in a partition member surrounding the optical path member of the gas concentration detector according to the first embodiment. 3 is a block diagram showing a part of the configuration of the gas concentration detector according to Embodiment 1. FIG. FIG. 3 is a flowchart showing a detailed flow when calibrating the gas concentration detector according to the first embodiment. It is a figure which shows the density | concentration change of the carbon dioxide in the cover member after installing the calibration assistance tool for gas concentration detectors which concerns on Embodiment 1. FIG. FIG. 6 is a schematic cross-sectional view showing an attached state of a calibration aid for a gas concentration detector according to Embodiment 2. It is a schematic sectional drawing which shows the other positional relationship of a tubular member and the calibration assistance tool for gas concentration detectors. FIG. 10 is a schematic cross-sectional view showing a state in which a gas concentration detector calibration aid according to Embodiment 3 is attached. It is a schematic sectional drawing which shows the attachment state of the calibration assistance tool for gas concentration detectors which concerns on Embodiment 4. FIG. 10 is a schematic cross-sectional view showing a state in which a calibration aid for a gas concentration detector according to Embodiment 5 is attached.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or common parts are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is an exploded perspective view of the gas concentration detection apparatus according to the first embodiment. FIG. 2 is a schematic cross-sectional view showing an installation state in which the gas concentration detection device according to the present embodiment is installed in a duct. With reference to FIG. 1 and FIG. 2, the gas concentration detection apparatus 1 which concerns on this Embodiment is demonstrated.

  As shown in FIGS. 1 and 2, the gas concentration detection device 1 is a device that takes in a flowing measurement target gas and measures the concentration of a specific gas contained in the measurement target gas. The gas concentration detection device 1 is, for example, control of ventilation based on carbon dioxide concentration in BEMS (Building Energy Management System), control of keeping indoor carbon dioxide concentration within a predetermined range in a plant cultivation facility, or the like. Used for.

  The gas concentration detection device 1 includes a housing 30, a gas concentration detector 40, a tubular member 80, and a wind direction guide plate 90.

  The housing 30 includes a first housing 10 and a second housing 20. The housing 30 accommodates the gas concentration detector 40 therein. The housing 30 is provided with an introduction port 15 into which a measurement target gas is introduced from the outside. A tubular member 80 is connected to the introduction port 15.

  The first housing 10 has a box shape in which one main surface located on the one end 10a side is opened. The first housing 10 includes a bottom portion 11, a peripheral wall portion 12 connected to the periphery of the bottom portion 11, a maintenance opening portion 13, and a first engagement portion 14 that protrudes outward from the peripheral wall portion 12.

  The second housing 20 closes the maintenance opening 13 so that it can be opened and closed. The second housing 20 includes a transparent part 22, a frame-like part 21 surrounding the transparent part 22, and a second engagement part 23 provided on the frame-like part 21.

  The transparent portion 22 is located at the approximate center of the second housing 20. The inside of the housing 30 can be seen through the transparent portion 22. The second engaging portion 23 is detachably engaged with the first engaging portion 14 of the first housing 10. When the second engaging portion 23 engages with the first engaging portion 14, the inside of the first housing 10 is sealed with the second housing 20.

  The gas concentration detector 40 is a non-dispersive infrared absorption method (NDIR method) gas concentration detector. The gas whose concentration is detected by the gas concentration detector 40 is, for example, carbon dioxide.

  The gas concentration detector 40 has an optical path member 44 that has an infrared optical path inside and is provided with a communication portion 46 that communicates the optical path with an external space, and a light source 50 (FIG. 3) as an infrared irradiation element installed in the optical path. And a pyroelectric sensor 54 (see FIG. 3) as an infrared light receiving element. The measurement target gas introduced into the optical path via the communication portion 46 is irradiated with infrared rays using the light source 50, and the measurement target gas is irradiated. The pyroelectric sensor 54 receives the emitted infrared light to detect the concentration of the specific gas included in the measurement target gas.

  The gas concentration detector 40 further includes a circuit board 42 as a board part. The circuit board 42 has a plate shape and includes a main surface 42b on the side where the optical path member 44 is mounted and a main surface 42a on the side where the optical path member 44 is not mounted. The gas concentration detector 40 is arranged such that the main surface 42 a on the circuit board 42 on which the optical path member 44 is not mounted faces the bottom 11 of the first housing 10. The gas concentration detector 40 is disposed at a predetermined distance from the bottom 11 of the first housing 10. A detailed configuration of the gas concentration detector 40 will be described later with reference to FIGS. 3 and 4.

  The tubular member 80 has a cylindrical shape having one end and the other end. The tubular member 80 connects the duct 100 and the housing 30. The tubular member 80 is detachably attached to the duct 100 and is detachably attached to the housing 30. The tubular member 80 may be formed integrally with the housing 30 by injection molding or the like.

  One end side of the tubular member 80 is connected to the through hole 101 of the duct 100. One end of the tubular member 80 may protrude toward the inside of the duct 100 while being connected to the duct 100.

  The other end side of the tubular member 80 is connected to the introduction port 15 of the housing 30. The tubular member 80 protrudes outward from the bottom 11 of the first housing 10 in a state where it is connected to the housing 30. The other end of the tubular member 80 may protrude toward the inside of the housing 30 while being connected to the housing 30.

  The tubular member 80 has a flange portion 81 protruding outward in the radial direction. The flange portion 81 is provided on one end side of the tubular member 80. The flange portion 81 contacts the outer peripheral surface of the duct 100 in a state where the tubular member 80 is connected to the duct 100.

  The wind direction guide plate portion 90 has, for example, a plate shape. The wind direction guide plate portion 90 extends along the tube axis direction of the tubular member 80. The wind direction guide plate portion 90 is provided so as to protrude from the bottom portion 11 of the first housing 10 through the inside of the tubular member 80 toward the outside rather than the one end 80 a of the tubular member 80. The wind direction guide plate portion 91 is a part for introducing the measurement target gas into the housing 30 from the outside and leading out the measurement target gas from the inside of the housing 30 to the outside.

  The tip of the wind direction guide plate portion 90 on the side projecting outward from one end of the tubular member 80 is located inside the duct 100.

  When the wind direction guide plate portion 90 is disposed in an environment in which the measurement target gas flows in a predetermined direction, the wind improving flow side becomes positive pressure as viewed from the wind direction guide plate portion 90, and the wind direction as viewed from the wind direction guide plate portion 90. The downstream side becomes negative pressure. The wind direction guide plate portion 90 is provided so as to intersect the flow direction of the measurement target gas. When the differential pressure is generated between the wind improving flow side and the wind direction downstream side when viewed from the wind direction guide plate portion 90, the wind direction guide plate portion 90 introduces the measurement target gas into the inside of the tubular member 80 and the housing 30. And a lead-out portion 83 for leading the measurement target gas to the outside of the housing 30.

  Further, the wind direction guide plate section 90 divides the introduction port 15 into an introduction hole 16 through which the measurement target gas is introduced and a lead-out hole 17 through which the measurement target gas is derived. The introduction hole 16 communicates with the above-described introduction part 82, and the lead-out hole 17 communicates with the above-described lead-out part 83.

  A part of the measurement target gas flowing on the wind improving flow side as viewed from the wind direction guide plate portion 90 is drawn into the introduction portion 82 of the tubular member 80 by the differential pressure. The measurement target gas drawn into the introduction portion 82 of the tubular member 80 is introduced into the housing 30 through the introduction hole 16.

  The measurement target gas introduced into the housing 30 enters the optical path member 44 through the communication portion 46 provided in the optical path member 44 when circulating in the housing 30. The measurement target gas that has entered the optical path member 44 is discharged into the housing 30 through the communication portion 46. In addition, in the case where the optical path member 44 is provided with another communication part other than the communication part 46, the measurement target gas that has entered the optical path member 44 passes through the communication part 46 and the other communication part in the housing 30. To be released. Then, the light is led into the duct 100 through the lead-out hole 17 and the lead-out portion of the tubular member 80 in order.

  FIG. 3 is a schematic diagram of the gas concentration detector according to the present embodiment. With reference to FIG. 3, the gas concentration detector 40 according to the present embodiment will be described.

  As shown in FIG. 3, the gas concentration detector 40 includes an optical path member 44, a concentration detection unit 60 (see FIG. 4) that performs a gas concentration detection operation, and a thermistor that is a temperature detection unit that detects the temperature of the gas. 58 and a circuit board 42. The optical path member 44 is provided at a predetermined position on one surface of the circuit board 42. The components of the concentration detector 60 and the thermistor 58 are provided at predetermined positions inside the optical path member 44.

  The density detection unit 60 includes a light source 50, a pyroelectric sensor 54, and a switching device 62 that switches a plurality of types of filters.

  The light source 50 is a filament lamp. However, the light source 50 may be a light source that emits infrared rays, such as an LED (Light Emitting Diode), as long as it emits a wavelength including at least infrared rays. The light source 50 is controlled to blink at a predetermined cycle. The light source 50 is held by a holding base that is a part of the optical path member 44. The light source 50 is provided at a position separated from the pyroelectric sensor 54 by a predetermined distance. The light source 50 emits infrared rays toward the pyroelectric sensor 54. An optical path portion 48 is formed between the light source 50 and the pyroelectric sensor 54 when the light source 50 emits infrared rays. Specifically, the optical path portion 48 is formed by reflecting the infrared rays emitted from the light source 50 by the inner wall surface of the optical path member 44.

  The cross-sectional shape of the holding table is a semi-elliptical shape opened to the pyroelectric sensor 54 side. The inside of the semi-elliptical shape is a mirror surface. That is, the holding table is a part of the elliptical mirror. The light source 50 is provided at the focal point of the semi-elliptical shape of the holding table. A part of the elliptical mirror is also formed on the optical path member 44. As shown in FIG. 3, the light source 50 and the pyroelectric sensor 54 are not facing each other but facing each other in a positional relationship shifted in the vertical direction on the paper surface of FIG. The inner wall surface of the optical path member 44 is made of a highly reflective member. The direction (angle) of the inner wall surface of the optical path member 44 is determined in advance so that an optical path portion 48 in which infrared rays emitted from the light source 50 are directed to the pyroelectric sensor 54 is formed. Therefore, infrared rays emitted from the light source 50 pass through the optical path portion 48 and enter the pyroelectric sensor 54, or after reflecting off the mirror surface on which the holding base is formed, pass through the optical path portion 48 and pyroelectric. Or enter the sensor 54.

  The pyroelectric sensor 54 is a pyroelectric infrared sensor using bulk ceramics. The pyroelectric sensor 54 is provided with an incident window 56, which is a portion that receives infrared rays emitted from the light source 50, facing the light source 50.

  The switching device 62 is provided between the light source 50 and the pyroelectric sensor 54. The switching device 62 applies a first bandpass filter (not shown) or a second bandpass filter (not shown) on the optical path between the light source 50 and the pyroelectric sensor based on a control signal from a switching drive circuit 78 described later. To place. The switching device 62 is, for example, an actuator such as a motor, and switches between a first bandpass filter and a second bandpass filter.

  The first band-pass filter is a filter that passes infrared light in the first wavelength band including the vicinity of 4.26 μm, which is a wavelength having a high carbon dioxide absorption rate. The pyroelectric sensor 54 receives infrared rays in the first wavelength band among infrared rays emitted from the light source 50 when the first band pass filter is arranged on the optical path by the switching device 62. Then, the output value of the pyroelectric sensor 54 is converted into the concentration of carbon dioxide.

  The second band-pass filter emits infrared light in a second wavelength band that includes a wavelength (for example, 3.9 μm) that is a wavelength band different from the first wavelength band and has a low absorption rate of a gas whose concentration is to be detected. It is a filter that passes. The pyroelectric sensor 54 receives infrared rays in the second wavelength band among infrared rays emitted from the light source 50 when the second band pass filter is arranged on the optical path by the switching device 62.

  The thermistor 58 is provided in the vicinity of the pyroelectric sensor 54 and is fixed to the circuit board 42. In the thermistor 58, a constant current flows when a voltage is applied from the drive circuit 70, and a voltage generated when the constant current flows is detected in the drive circuit 70 as an output voltage.

  The optical path member 44 is provided so as to cover the components of the concentration detector 60 and the thermistor 58 and is fixed to the circuit board 42. The optical path member 44 is provided with a communication portion 46 for taking in gas from the outside of the optical path member 44 and discharging gas inside the optical path member 44. The communication part 46 is provided with an air filter.

  The detection of the concentration of carbon dioxide by the gas concentration detector 40 is performed in a state where gas is taken into the optical path member 44 from the communication portion 46. When infrared rays are emitted from the light source 50 toward the pyroelectric sensor 54, the emitted infrared rays are received by the pyroelectric sensor 54. The pyroelectric sensor 54 outputs a voltage in response to infrared light reception.

  When the first bandpass filter is disposed on the optical path, the voltage output from the pyroelectric sensor 54 varies depending on the concentration of carbon dioxide in the optical path unit 48. This is because, among infrared rays radiated from the light source 50, infrared rays in the first wavelength band that pass through the first bandpass filter are absorbed by carbon dioxide on the optical path portion 48. This is because the amount of infrared rays reaching the pyroelectric sensor 54 via the one-band pass filter also changes (Lambert-Beer's law).

  When the second bandpass filter is disposed on the optical path, the voltage output from the pyroelectric sensor 54 does not change according to the concentration of carbon dioxide in the optical path section 48. This is because the infrared of the second wavelength band that passes through the second bandpass filter among the infrared rays radiated from the light source 50 is hardly absorbed by carbon dioxide or other gases. Thus, the second band pass filter functions as a filter that transmits the reference wavelength.

  FIG. 4 is a circuit configuration diagram of the gas concentration detector according to the present embodiment. With reference to FIG. 4, the circuit configuration of the gas concentration detector 40 according to the present embodiment will be described.

  As shown in FIG. 4, the drive circuit 70 formed on the circuit board 42 includes an amplification circuit 72, an AD conversion circuit 74, a density conversion processing circuit 76, and a switching drive circuit 78. The circuit configuration of the gas concentration detector 40 shown in FIG. 4 is an example, and is not limited to the circuit configuration shown in FIG.

  The amplifier circuit 72 is configured by, for example, an amplifier, and amplifies the signal intensity of the concentration detection signal (output voltage) of the concentration detection unit 60.

  The AD conversion circuit 74 converts the analog signal whose signal strength is amplified in the amplification circuit 72 into a digital signal. A well-known technique may be used for amplification of signal intensity and conversion from an analog signal to a digital signal.

  The concentration conversion processing circuit 76 calculates a concentration of carbon dioxide contained in the gas taken into the optical path member 44 by performing a predetermined process on the digital signal converted by the AD conversion circuit 74. In the present embodiment, the density conversion processing circuit 76 is realized by, for example, a CPU (Central Processing Unit).

  The CPU executes predetermined arithmetic processing and control processing by executing a program stored in a storage unit (not shown). The CPU, for example, in addition to the calculation process for calculating the concentration of carbon dioxide, the control process for turning on the light source 50, the control process for applying a voltage to the thermistor 58, and the switching device 62 are operated to operate the first bandpass filter or A control process for arranging the second band pass filter on the optical path between the light source 50 and the pyroelectric sensor 54 is executed.

  The CPU outputs a drive command to the switching drive circuit 78 when operating the switching device 62. The switching drive circuit 78 generates a control signal in accordance with the drive command received from the CPU and outputs the control signal to the switching device 62.

  When the gas concentration detector 40 detects the concentration of the specific gas (carbon dioxide), the temperature detection signal is acquired from the thermistor 58 and the output value of the pyroelectric sensor 54 is acquired. Predetermined signal processing such as noise removal, amplification processing, and digital data conversion processing is executed on the acquired output value of the pyroelectric sensor 54. The concentration of carbon dioxide is calculated from the thermistor temperature calculated based on the temperature detection signal from the thermistor and the output value of the pyroelectric sensor 54.

  Specifically, the gas concentration detector 40 calculates the concentration of carbon dioxide based on the output value V of the pyroelectric sensor 54 and the first and second calibration curves acquired in advance.

The first calibration curve shows the relationship between the concentration of carbon dioxide at a predetermined reference temperature and the value (V / V ₀ ) obtained by normalizing the output value V of the pyroelectric sensor 54 with the reference output value V ₀ . The reference output value V ₀ is an output value of the pyroelectric sensor 54 corresponding to the thermistor temperature Th when the concentration of carbon dioxide is a predetermined reference concentration (for example, 0 ppm). The second calibration curve shows the relationship between the thermistor temperature Th and the reference output value V ₀ at a predetermined reference concentration (for example, 0 ppm).

  The data relating to the first calibration curve and the data relating to the second calibration curve are acquired in advance at the time of manufacturing the gas concentration detector 40 and stored in a storage medium such as a memory provided in the drive circuit 70.

The thermistor temperature Th is calculated, the reference output value V ₀ is calculated based on the second calibration curve, and the calculated reference output value V ₀ , the output value V of the pyroelectric sensor 54 and the first calibration curve are calculated. Thus, the concentration of the specific gas (carbon dioxide) can be calculated.

  In the gas concentration detector 40, it is known that the calculated concentration drifts due to aging of the constituent members. For this reason, it is necessary to periodically calibrate the gas concentration detector 40 using a calibration gas having a known concentration.

  FIG. 5 is an exploded perspective view of the gas concentration detection device and the calibration aid for the gas concentration detector according to the present embodiment. With reference to FIG. 5, the gas concentration detector calibration aid 200 will be described.

  The gas concentration detector calibration auxiliary tool 200 according to the present embodiment includes an absorbent 220 capable of absorbing a specific gas and a cover member capable of accommodating the absorbent 220 therein. The cover member in the present embodiment is configured by a frame-shaped partition member 210 having both ends (210a, 210b) that are different from the housing 30, and a part of the second housing 20.

  The partition member 210 includes a first frame-like portion 211, a second frame-like portion 212, a connection portion 213, and an absorbent support portion 214. The partition member 210 is made of, for example, a resin member.

  The first frame portion 211 has a cylindrical shape. The first frame-shaped part 211 has, for example, a rectangular tube shape. When viewed from the axial direction of the partition member 210, the outer shape of the first frame-shaped portion 211 is smaller than the outer shape of the circuit board 42. As a result, the first frame portion 211 is provided so as to be placed on the circuit board 42. In other words, the end of the first frame-shaped portion 211 opposite to the side on which the second frame-shaped portion 212 is located (one end 210a of the partition member 210) is provided so as to be in contact with the circuit board 42. The first frame portion 211 surrounds the optical path member 44 in a state of being placed on the circuit board 42.

  The second frame portion 212 has a cylindrical shape. The second frame-shaped part 212 has, for example, a rectangular tube shape. The outer shape of the second frame portion 212 is larger than the outer shape of the first frame portion 211. An end portion (the other end 210b of the partition member 210) of the second frame-like portion 212 located on the opposite side to the side where the first frame-like portion 211 is located is configured to be able to contact the inner surface of the second housing 20. ing.

  Each of the open one end 210a and the other end 210b of the frame-shaped partition member 210 is provided with a seal portion that can be elastically deformed. That is, the second frame shape located on the opposite side of the end portion of the first frame shape portion 211 located on the side opposite to the side on which the second frame shape portion 212 is located and the side on which the first frame shape portion 211 is located. An elastically deformable seal portion is provided at the end of the portion 212.

  The connection part 213 connects the end part of the first frame part 211 located on the second frame part 212 side and the end part of the second frame part 212 located on the first frame part 211 side.

  The absorbent support 214 is configured to support the absorbent 220. The absorbent support 214 is provided so that the space in the partition member 210 communicates in the cylinder axis direction. The absorbent support 214 is provided in a lattice shape, for example. The space in the first frame portion 211 and the space in the second frame portion 212 communicate with each other through openings 215 provided between the lattices constituting the absorbent support portion 214.

  The absorbent 220 absorbs the specific gas. The absorbent 220 is obtained by, for example, filling a bag body provided with a plurality of holes communicating inside and outside with an absorbent that absorbs a specific gas.

  When carbon dioxide is absorbed as the specific gas, any of soda lime, zeolite, or activated carbon can be employed as the absorbent used for the absorbent 220. For example, when soda lime is employed, carbon dioxide is reduced by neutralizing the soda lime and carbon dioxide. In the case where carbon monoxide, methane, or nitrogen oxide is absorbed as the specific gas, either zeolite or activated carbon can be adopted as the absorbent.

  FIG. 6 is a flowchart of the gas concentration detector calibration method according to the present embodiment. FIG. 7 to FIG. 9 are an exploded perspective view showing a predetermined step among the steps shown in FIG. 6 and a plan view showing a state after the predetermined step. A calibration flow of the gas concentration detector according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 6, in the step (S0), the second housing 20 is removed and the maintenance opening 13 is opened. In this open state, the gas concentration detector 40 is installed on a predetermined installation surface in the first housing 10. Specifically, in the gas concentration detector 40, the circuit board 42 is placed on a placement portion provided in the first housing, and the placement surface of the placement portion corresponds to the installation surface.

  Next, the absorbent 220 and the cover member are attached to the gas concentration detector 40 in step (S1).

  Specifically, the absorbent 220 and the cover member are connected to the optical path portion 48 through which infrared rays pass through the communicating portion 46 provided in the optical path member 44, and the absorbent 220 is connected to the optical path by the cover member. It is attached to the gas concentration detector 40 so as to be separated from the outside air outside the member 44. At this time, the gas concentration detector 40 is installed on the installation surface without being removed from the installation surface.

  More specifically, the step (S1) includes a step (S1A), a step (S1B), and a step (S1C). By performing these steps (S1A) to (S1C), the absorbent is performed. 220 and the cover member are attached to the gas concentration detector 40.

  FIG. 7 is an exploded perspective view showing a process of surrounding the optical path member of the gas concentration detector according to the present embodiment. As shown in FIGS. 6 and 7, in step (S <b> 1 </ b> A), the open end 220 a of the partition member 210 is brought into contact with the circuit board 42, so that the optical path member 44 is moved inside the first housing 10. Go by.

  FIG. 8 is a plan view showing a state after the step of surrounding the optical path member of the gas concentration detector according to the present embodiment by the partition member. In FIG. 8, the absorbent support 214 is omitted for convenience.

  As shown in FIG. 8, in a state after the step of surrounding the optical path member 44 of the gas concentration detector 40 by the partition member 210, the guide portion 44 </ b> A provided in the optical path member 44 and the first frame-shaped portion 211. The guided portion 211c provided on the inner peripheral wall portion is engaged.

  44 A of guide parts are comprised by the projection part which protrudes toward the outer side from the outer peripheral wall part of the optical path member 44, for example. The guided portion 211c is constituted by, for example, a groove extending in the cylinder axis direction.

  When the partition member 210 is placed on the circuit board 42, positioning can be easily performed by engaging the guided portion 211c with the guide portion 44A. Further, by engaging the guided portion 211c with the guide portion 44A, the movement of the partition member 210 is guided by the guide portion 44A.

  Subsequently, as shown in FIG. 6, the absorbent 220 is put into the partition member 210 in the step (S1B). Specifically, the absorbent 220 is placed on the absorbent support 214 of the partition member 210. FIG. 9 is an exploded perspective view showing a state after the step of putting the absorbent in the partition member surrounding the optical path member of the gas concentration detector according to the present embodiment.

  As shown in FIG. 9, in the state after the step of putting the absorbent in the partition member surrounding the optical path member 44 of the gas concentration detector, the other end 210b side of the partition member 210 is opened toward the outside air. ing.

  Next, in the step (S1C), the second housing 20 is brought into contact with the other end 210b of the partition member 210 opened by closing the maintenance opening 13 with the second housing 20. Accordingly, the space around the optical path member 44 of the gas concentration detector 40 is partitioned by the circuit board 42, the partition member 210, and a part of the second housing 20.

  As described above, each of the opened one end 210a and the other end 210b of the partition member 210 is provided with a seal portion that can be elastically deformed. The seal portion located on the one end 210a side is in close contact with the circuit board 42, and the seal portion located on the other end 210b side is in close contact with the inner surface of the second housing. Thereby, the airtightness of the space is improved.

  In the space partitioned by the circuit board 42, the partition member 210, and a part of the second housing 20, an absorbent 220 is disposed. The absorbent 220 passes through the communication portion 46 provided in the optical path member 44. To the optical path in the optical path member 44.

  Subsequently, as shown in FIG. 6, the concentration of the specific gas in the optical path 48 is reduced by maintaining the state where the cover member and the absorbent 220 are attached to the gas concentration detector 40 in the step (S2). Let

  Specifically, the absorbent 220 is maintained in a space partitioned by the partition member 210 and a part of the second housing 20, and the absorbent 220 reduces the specific gas in the space. To do. Thereby, the concentration of carbon dioxide in the space is lowered, and consequently, the concentration of carbon dioxide in the optical path portion 48 in the optical path member 44 is lowered.

  Next, as shown in FIG. 6, in the step (S3), the gas concentration detector 40 is calibrated in a state where the concentration of carbon dioxide in the optical path portion 48 is lowered.

  FIG. 10 is a block diagram showing a part of the configuration of the gas concentration detector according to the present embodiment. A part of the configuration of the gas concentration detector 40 according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 10, the gas concentration detector 40 is configured to be able to switch between a normal measurement mode and a calibration mode. Switching between the normal measurement mode and the calibration mode is performed by a control unit constituting a part of the drive circuit 70. In addition, a timer 130 is incorporated in the drive circuit 70.

  The gas concentration detector 40 has an LED 110 and a button 120. The LED 110 and the button 120 are mounted on the circuit board 42. For example, the LED 110 is configured to light in a predetermined color when in the calibration mode, and is configured to light in another color when the calibration of the gas concentration detector 40 is completed. The control unit determines that the calibration mode has been changed by pressing the button 120.

  FIG. 11 is a flowchart showing a detailed flow when the gas concentration detector according to the present embodiment is calibrated. With reference to FIG. 11, the detailed flow at the time of calibrating the gas concentration detector 40 which concerns on this Embodiment is demonstrated.

  As shown in FIG. 11, when calibrating the gas concentration detector 40, the normal measurement mode is changed to the calibration mode in step (S10). When the second housing 20 is removed and the operator presses the button 120 provided on the circuit board 42 as described above, the calibration mode is changed. The timing of pressing the button 120 is preferably pressed after the absorbent and the cover member are attached to the gas concentration detector 40.

  Next, in the step (S11), the absorbent and the cover member are attached to the gas concentration detector 40, the space around the gas concentration detector 40 is partitioned, and the carbon dioxide in this space is removed using the absorbent 220. Reduce. Specifically, the space around the gas concentration detector 40 is a gas concentration detector partitioned by the circuit board 42, the partition member 210, and a part of the second housing 20 in a state where the second housing 20 is attached. A space around 40 optical path members 44. The concentration and temperature in this space are measured using the gas concentration detector 40 and the thermistor 58.

  Next, in step (S12), it is determined whether the concentration change and temperature change within a predetermined time are within a predetermined range.

  When it is determined that the concentration change and temperature change within a predetermined time are within the predetermined range (step (S12); YES), step (S13) is performed. When it is determined that the concentration change and temperature change within a predetermined time are outside the predetermined range (step (S12); NO), the steps from step (S11) are repeated.

  Subsequently, in the step (S13), calibration processing is executed. When executing the calibration process, the correction coefficient is calculated from the management value recorded in the memory and the measured value in the zero concentration environment. Next, the correction coefficient for calibration is rewritten. Specifically, the above-described second calibration curve is calibrated using the calculated correction coefficient. After step (S13) is performed, step (S14) is performed.

  In step (S14), the LED 110 is lit in a desired color. Thus, the operator confirms that the calibration is completed. In step (S15), the calibration mode ends.

  The detailed flow for calibrating the gas concentration detector described above exemplifies a case where the operator presses the button 120 when changing from the normal measurement mode to the calibration mode in the step (S10). Although explained, it is not limited to this, When the cover member is attached to the gas concentration detector 40, the button 120 may be pushed by the cover member (partition member). In addition, a weight sensor or the like is attached to the first housing 10, and when the second housing 20 is removed, the weight sensor may detect a change in weight, so that the calibration mode may be changed. When the weight sensor detects that the housing 20 is attached again, the calibration mode may be changed.

  FIG. 12 is a diagram showing a change in the concentration of carbon dioxide in the cover member after the gas concentration detector calibration aid according to the present embodiment is installed. With reference to FIG. 12, the change in the concentration of carbon dioxide in the cover member after the gas concentration detector calibration aid according to the present embodiment is installed will be described.

  The gas concentration detector calibration assisting tool 200 according to the present embodiment was attached to the gas concentration detecting device 1, and the change in the concentration of carbon dioxide in the cover member was confirmed. In addition, after a predetermined time has elapsed since the calibration aid 200 for gas concentration detector was attached, 1000 ppm of carbon dioxide is supplied into the housing 10 from the inlet 15, and the change in the concentration of carbon dioxide in the cover member at that time is changed. confirmed.

  Soda lime was used as the absorbent 220. The amount of soda lime was 15 g, and the capacity in the partition member 210 was approximately 60 cc.

  As shown in FIG. 12, when the gas concentration detector calibration auxiliary tool 200 is installed so as to cover the optical path member 44 in the housing 10 of the gas concentration detection apparatus into which the measurement target gas containing approximately 450 ppm of carbon dioxide is introduced. The concentration of carbon dioxide in the cover member (specifically, in the space partitioned by the partition member 210 and a part of the second housing 20) became 0 ppm in about 7 minutes.

  Further, even when 1000 ppm of carbon dioxide is introduced into the housing 10 located outside the cover member in a state where the concentration of carbon dioxide in the cover member is 0 ppm, the cover member is separated from the outside air. The carbon dioxide concentration in the cover member was maintained at 0 ppm.

  Thus, by using the calibration aid for gas concentration detector in this embodiment, it is possible to create a zero concentration environment (calibration gas) in which the concentration of carbon dioxide is 0 ppm, and this zero concentration. It was confirmed that the environment could be maintained.

  As described above, the calibration aid 200 for gas concentration detector according to the present embodiment is configured by the absorbent 220 and the cover member, so that the configuration is simplified and the manufacturing cost can be reduced. .

  Further, the absorbent 220 and the cover member are communicated with the optical path portion 48 through the communication portion 46 and the absorbent 220 is separated from the outside air outside the optical path member 44 by the cover member. By attaching to the concentration detector 40, a calibration gas with a specific gas concentration of 0 ppm can be easily manufactured.

  As a result, when the gas concentration detector is calibrated as in the prior art, a pump for inhaling the atmosphere, a drive unit for operating the pump, an absorbent for reducing carbon dioxide, and the atmosphere There is no need to prepare a calibration gas production apparatus having a large-scale configuration equipped with an air filter or the like for removing contained dust or the like.

  Moreover, in the gas concentration detector calibration auxiliary tool 200 according to the present embodiment, an environment in which the concentration of the specific gas is 0 ppm can be easily manufactured without using electric power. It is necessary to secure a separate outlet plug, and the configuration of a battery or the like is also unnecessary.

  Furthermore, since the gas concentration detector calibration aid 200 according to the present embodiment is configured simply and inexpensively, a plurality of calibration aids 200 can be easily prepared. This makes it possible to simultaneously calibrate a plurality of gas concentration detectors according to the number of prepared units, and it takes more time for the operator than when calibrating one by one using a conventional calibration gas production apparatus. Save time and effort.

  In addition, when the absorbent 220 and the cover member are attached to the gas concentration detector 40, it is not necessary to remove the gas concentration detector 40 from the installation surface. It can be omitted.

  Further, by configuring the partition member 210 so as to surround the optical path member 44, the calibration assist for the gas concentration detector is compared with the case where the partition member is configured so as to surround the entire gas concentration detector 40. The tool 200 can be further downsized.

  Using the method for calibrating a gas concentration detector according to the present embodiment, an absorbent capable of absorbing a specific gas and a cover member capable of accommodating the absorbent are passed through the optical path through the communicating portion. By maintaining the state where the cover member and the absorbent are attached to the gas concentration detector after being attached to the gas concentration detector so that the absorbent is separated from the outside air by the cover member outside the optical path member In the state where the concentration of the specific gas in the optical path is reduced and the concentration of the specific gas in the optical path is reduced, the calibration gas is calibrated so that the concentration of the specific gas becomes 0 ppm without using power. It can be manufactured and the gas concentration detector can be calibrated.

(Embodiment 2)
FIG. 13 is a schematic cross-sectional view showing an attached state of the gas concentration detector calibration aid according to the present embodiment. With reference to FIG. 13, a calibration aid 200A for a gas concentration detector according to the present embodiment will be described.

  As shown in FIG. 13, the gas concentration detector calibration auxiliary tool 200 </ b> A according to the present embodiment accommodates the absorbent 220 inside when compared with the gas concentration detector calibration auxiliary tool 200 according to the first embodiment. Possible cover member configurations are different. Note that the gas concentration detection device according to the present embodiment has substantially the same configuration as the gas concentration detection device 1 according to the first embodiment.

  The cover member according to the present embodiment is configured by a partition member 210A having a box shape with an open main surface located on the one end 210a side. The partition member 210A is configured so that one end 210a of the partition member 210A abuts the first housing 10 and covers the gas concentration detector 40 when the second housing 20 is removed and the maintenance opening 13 is opened. It is configured to be attachable to one housing 10. An elastically deformable seal portion is provided at the open end 210a of the partition member 210A.

  For example, the height of the partition member 210A (the distance from the one end 210a to the other end 210b) is larger than the height of the first housing 10 (the distance from the one end 10a to the other end 10b). 10, the other end 210 b of the partition member 210 </ b> A protrudes from the maintenance opening 13 to the outside of the first housing 10.

  When the gas concentration detector 40 is calibrated using the gas concentration detector calibration auxiliary tool 200A, a process based on the gas concentration detector calibration method according to the first embodiment is performed. Specifically, in a step according to the step (S0), the second housing 20 is removed and the maintenance opening 13 is opened.

  Subsequently, in the step according to the step (S1), the absorbent 220 and the partition member 210A are connected to the optical path portion 48 through which the infrared ray passes through the communicating portion 46 provided in the optical path member 44. The absorber 220 is attached to the gas concentration detector 40 so as to be separated from the outside air outside the optical path member 44 by the partition member 210A. At this time, the gas concentration detector 40 is installed on the installation surface without being removed from the installation surface.

  Specifically, in a state where the absorbent 220 is accommodated in the partition member 210A, the open end 210a of the partition member 210A is brought into contact with the first housing 10, and the gas concentration detector 40 is covered by the partition member 210A. Thus, attaching to the gas concentration detector 40 means attaching to the gas concentration detector 40, and attaching the partition member 210A to the first housing 10 as in the present embodiment. Is included.

  By attaching the partition member 210A to the bottom portion 11 of the first housing 10 so as to cover the gas concentration detector 40, the inner surface of the bottom 11 of the first housing 10 and the space around the gas concentration detector 40 are formed by the partition member 210A. Partitioned from outside air.

  As described above, the open end 210a of the partition member 210A is provided with a seal portion that can be elastically deformed. When the partition member 210 </ b> A is brought into contact with the first housing 10, the seal portion is in close contact with the bottom portion 11 of the first housing 10. Thereby, it can suppress that external air penetrate | invades in the division member 210A.

  During calibration, the gas to be measured enters the partition member 210 </ b> A through the introduction port 15 provided in the housing 30. In such a case, the concentration of the specific gas is set to 0 ppm by making the absorption capacity of the absorbent 220 larger than the amount of the specific gas contained in the measurement target gas entering the partition member 210A through the inlet 15. It becomes possible to.

  Subsequently, in a step according to the step (S2), the partition member is attached to the first housing 10 so as to cover the gas concentration detector 40 in a state where the partition member 210A and the absorbent 220 are attached to the gas concentration detector 40. By maintaining the attached state with 210A, the concentration of the specific gas in the optical path portion 48 is reduced.

  Next, the gas concentration detector 40 is calibrated in a state in which the concentration of the specific gas in the optical path portion 48 is lowered in a step according to the step (S3).

  In the present embodiment, the case where the height of the partition member 210A is larger than the height of the first housing 10 has been described as an example. However, the present invention is not limited to this and is smaller than the height of the first housing 10. Also good. In this case, it is preferable that the maintenance opening 13 is closed by the second housing 20 prior to the step according to the step (S2). At this time, it is preferable to attach a member having a transparent window as the second housing 20 so that the internal state can be understood. Thereby, the density | concentration of the specific gas in 210 A of division members can be reduced stably. FIG. 14 is a schematic sectional view showing another positional relationship between the tubular member and the gas concentration detector calibration aid. As shown in FIG. 14, when the tubular member 80 is connected to the bottom 11 of the first housing 10 at a portion exposed from the partition member 210A, the measurement target gas is directly introduced into the partition member 210A from the tubular member 80. Therefore, the concentration of the specific gas in the partition member 210A can be more stably reduced.

  As described above, by using the calibration aid for the gas concentration detector or the calibration method for the gas concentration detector according to the present embodiment, the concentration of the specific gas is 0 ppm without using electric power as in the first embodiment. Can be easily formed. Thereby, substantially the same effect as in the first embodiment can be obtained.

(Embodiment 3)
FIG. 15 is a schematic cross-sectional view showing the attached state of the calibration aid for gas concentration detector according to the present embodiment. With reference to FIG. 15, the calibration assistance tool 200B for gas concentration detectors which concerns on this Embodiment is demonstrated.

  As shown in FIG. 15, the gas concentration detector calibration auxiliary tool 200B according to the present embodiment accommodates the absorbent 220 in the interior thereof when compared with the gas concentration detector calibration auxiliary tool 200 according to the first embodiment. Possible cover member configurations are different. Note that the gas concentration detection device according to the present embodiment has substantially the same configuration as the gas concentration detection device 1 according to the first embodiment.

  The cover member according to the present embodiment is configured by a partition member 210B having a box shape with an open main surface located on the one end 210a side. In the open state in which the second housing 20 is removed and the maintenance opening 13 is opened, the partition member 210B is configured such that one end 210a of the partition member 210B contacts the circuit board 42 and covers the optical path member 44. It is configured to be attachable to. An elastically deformable seal portion is provided at one end 210a of the partition member 210B which is opened.

  For example, the height of the partition member 210B (the distance from the one end 210a to the other end 210b) is larger than the height of the first housing 10 (the distance from the one end 10a to the other end 10b). The other end 210b of the partition member 210B protrudes outside the first housing 10 from the maintenance opening 13.

  When the gas concentration detector 40 is calibrated using the gas concentration detector calibration auxiliary tool 200B, a process based on the gas concentration detector calibration method according to the first embodiment is performed. Specifically, in a step according to the step (S0), the second housing 20 is removed and the maintenance opening 13 is opened.

  Subsequently, in a step according to the step (S1), the absorbent 220 and the partition member 210B are communicated with the optical path portion 48 through which the infrared ray passes through the communicating portion 46 provided in the optical path member 44. At the same time, the absorbent 220 is attached to the gas concentration detector 40 so as to be separated from the outside air by the partition member 210B outside the optical path member 44. At this time, the gas concentration detector 40 is installed on the installation surface without being removed from the installation surface.

  Specifically, in a state where the absorbent 220 is accommodated in the partition member 210B, the open end 210a of the partition member 210B is brought into contact with the circuit board 42, and the optical path member 44 is covered by the partition member 210B.

  As described above, the open end 210a of the partition member 210B is provided with a seal portion that can be elastically deformed. When the partition member 210 </ b> B is brought into contact with the circuit board 42, the seal portion is in close contact with the circuit board 42. Thereby, it can suppress that external air penetrate | invades in the division member 210B.

  Subsequently, in a step according to the step (S2), the concentration of the specific gas in the optical path portion 48 is lowered by maintaining the state where the partition member 210B and the absorbent 220 are attached to the gas concentration detector 40.

  Next, the gas concentration detector 40 is calibrated in a state in which the concentration of the specific gas in the optical path portion 48 is lowered in a step according to the step (S3).

  In the present embodiment, the case where the height of the partition member 210B is larger than the height of the first housing 10 has been described as an example. However, the present invention is not limited to this and is smaller than the height of the first housing 10. Also good. In this case, it is preferable that the maintenance opening 13 is closed by the second housing 20 prior to the step according to the step (S2). Thereby, the density | concentration of the specific gas in the division member 210B can be reduced stably.

  As described above, by using the calibration aid for the gas concentration detector or the calibration method for the gas concentration detector according to the present embodiment, the concentration of the specific gas is 0 ppm without using electric power as in the first embodiment. Can be easily formed. Thereby, substantially the same effect as in the first embodiment can be obtained.

(Embodiment 4)
FIG. 16 is a schematic cross-sectional view showing an attached state of the calibration aid for gas concentration detector according to the present embodiment. Referring to FIG. 16, a gas concentration detector calibration aid 200C according to the present embodiment will be described.

  As shown in FIG. 16, the gas concentration detector calibration auxiliary tool 200C according to the present embodiment accommodates the absorbent 220 in the interior when compared with the gas concentration detector calibration auxiliary tool 200 according to the first embodiment. Possible cover member configurations are different. Note that the gas concentration detection device according to the present embodiment has substantially the same configuration as the gas concentration detection device 1 according to the first embodiment.

  The cover member according to the present embodiment is configured by a partition member 210C having a box shape with an open main surface located on the one end 210a side. In the opened state in which the second housing 20 is removed and the maintenance opening 13 is opened, the partition member 210C is configured such that the one end 210a of the partition member 210C contacts the optical path member 44 and covers the communication portion 46. It is configured to be attachable to. An elastically deformable seal portion is provided at one end 210a of the partition member 210C that is open.

  For example, in a state where the partition member 210C is attached to the optical path member 44, the other end 210b of the partition member 210C protrudes from the maintenance opening 13 to the outside of the first housing 10.

  When the gas concentration detector 40 is calibrated using the gas concentration detector calibration auxiliary tool 200C, a process based on the gas concentration detector calibration method according to the first embodiment is performed. Specifically, in a step according to the step (S0), the second housing 20 is removed and the maintenance opening 13 is opened.

  Subsequently, the absorbent 220 and the partition member 210C are attached to the gas concentration detector 40 in a step according to the step (S1).

  Specifically, in a state where the absorbent 220 is accommodated in the partition member 210C, the open end 210a of the partition member 210C is brought into contact with the optical path member 44, and the communication portion 46 is covered by the partition member 210C.

  As described above, the open end 210a of the partition member 210C is provided with a seal portion that can be elastically deformed. When the partition member 210 </ b> C is brought into contact with the optical path member 44, the seal portion is in close contact with the optical path member 44. Thereby, it can suppress that external air penetrate | invades in the division member 210C.

  Subsequently, the concentration of the specific gas in the optical path 48 is reduced by maintaining the state where the partition member 210C and the absorbent 220 are attached to the gas concentration detector 40 in a step according to the step (S2).

  Next, the gas concentration detector 40 is calibrated in a state in which the concentration of the specific gas in the optical path portion 48 is lowered in a step according to the step (S3).

  In the present embodiment, the case where the other end 210b of the partition member 210C is located outside the first housing 10 in a state where the partition member 210C is attached to the optical path member 44 has been described as an example. However, the present invention may be located inside the first housing 10. In this case, it is preferable that the maintenance opening 13 is closed by the second housing 20 prior to the step according to the step (S2). Thereby, the density | concentration of the specific gas in the division member 210C can be reduced stably.

  As described above, by using the calibration aid for the gas concentration detector or the calibration method for the gas concentration detector according to the present embodiment, the concentration of the specific gas is 0 ppm without using electric power as in the first embodiment. Can be easily formed. Thereby, substantially the same effect as in the first embodiment can be obtained.

(Embodiment 5)
FIG. 17 is a schematic cross-sectional view showing an attached state of the calibration aid for the gas concentration detector according to the present embodiment. With reference to FIG. 17, the calibration assistance tool 200D for gas concentration detectors which concerns on this Embodiment is demonstrated.

  As shown in FIG. 17, the gas concentration detector calibration aid 200D according to the present embodiment accommodates the absorbent 220 in the interior thereof when compared with the gas concentration detector calibration aid 200 according to the first embodiment. Possible cover members are different. Note that the gas concentration detection device according to the present embodiment has substantially the same configuration as the gas concentration detection device 1 according to the first embodiment.

  The cover member according to the present embodiment includes a frame-shaped partition member 210 </ b> D having both ends opened and a part of the second housing 20. The partition member 210D is configured such that, in the opened state in which the second housing 20 is removed and the maintenance opening 13 is opened, the open end 210a of the partition member 210D is brought into contact with the first housing 10 to thereby detect the gas concentration detector. 40 can be surrounded. Each of the opened one end 210a and the other end 210b of the partition member 210D is provided with an elastically deformable seal portion.

  The other end 210b of the partition member 210D is configured to be able to contact the inner surface of the second housing 20 that closes the maintenance opening 13 in a state where the one end 210a of the partition member 210D is in contact with the first housing 10. .

  When the gas concentration detector 40 is calibrated using the gas concentration detector calibration auxiliary tool 200D, a process based on the gas concentration detector calibration method according to the first embodiment is performed. Specifically, in a step according to the step (S0), the second housing 20 is removed and the maintenance opening 13 is opened.

  Subsequently, in a step according to the step (S1), the absorbent 220 and the partition member 210D are communicated with the optical path portion 48 through which the infrared ray passes through the communicating portion 46 provided in the optical path member 44. At the same time, the absorbent 220 is attached to the gas concentration detector 40 so as to be separated from the outside air outside the optical path member 44 by the partition member 210D. At this time, the gas concentration detector 40 is installed on the installation surface without being removed from the installation surface.

  Specifically, the gas concentration detector 40 is placed inside the first housing 10 by bringing the open end 210a of the partition member 210D into contact with the first housing 10 in a step according to the step (S1A). Surrounded by the partition member 210D.

  Subsequently, in a step according to the step (S1B), the absorbent 220 is put into the partition member 210D. Specifically, the absorbent 220 is placed on the absorbent support 214 of the partition member 210D.

  Next, in a step according to the step (S1C), the second housing 20 is closed to the other end 210b of the partition member 210D by closing the maintenance opening 13 with the second housing 20. Make contact. Thereby, the space around the gas concentration detector 40 is partitioned by the inner surface of the bottom 11 of the first housing 10, the partition member 210 </ b> D, and a part of the second housing 20.

  Thus, attaching to the gas concentration detector 40 means attaching to the gas concentration detector 40, and attaching the partition member 210D to the first housing 10 as in the present embodiment. Is included.

  Subsequently, in a step according to the step (S2), the partition member 210D and the absorbent 220 are attached to the gas concentration detector 40, that is, the partition member is disposed in the first housing 10 so as to cover the gas concentration detector 40. By maintaining the attached state with 210D, the concentration of the specific gas in the optical path 48 is reduced.

  Next, the gas concentration detector 40 is calibrated in a state in which the concentration of the specific gas in the optical path portion 48 is lowered in a step according to the step (S3).

  As described above, by using the calibration aid for the gas concentration detector or the calibration method for the gas concentration detector according to the present embodiment, the concentration of the specific gas is 0 ppm without using electric power as in the first embodiment. Can be easily formed. Thereby, substantially the same effect as in the first embodiment can be obtained.

  Although the gas concentration detector 40 according to Embodiments 1 to 5 described above has been described by exemplifying the case where it is installed in the housing 30, it is not limited to this, and the concentration of a specific gas in a room or duct is directly measured. In the case of measuring, it may be installed directly in the room or in the duct. For example, it is installed on the ceiling of the room or the wall of the duct. In this case, the wall of the room or the wall of the duct corresponds to the installation surface. Further, when calibrating, a procedure for opening the housing opening is not necessary, and the cover member containing the absorbent is connected to the gas concentration detector 40 from below the gas concentration detector 40 through the communication portion 46. The absorber is attached to the gas concentration detector so as to communicate with the optical path of the detector 40 and to be separated from the outside air outside the optical path member 44 by the cover member.

In the above-described embodiment, the gas whose concentration is detected by the gas concentration detector is carbon dioxide. However, the gas that is the detection target is not particularly limited to carbon dioxide. For example, a gas such as carbon monoxide, CH ₄ or NO _X may be used. When the concentration detection target is a gas other than carbon dioxide, the first wavelength band has a wavelength corresponding to the type of gas that is the concentration detection target (that is, the absorption rate of the gas that is the concentration detection target is A wavelength band based on (high wavelength) is selected.

  In the above-described embodiment, the switching device arranges the first band-pass filter or the second band-pass filter on the optical path between the light source and the pyroelectric sensor based on the control signal from the switching drive circuit. The filter was switched. The filter includes, on the optical path, a first wavelength band in which infrared rays are absorbed higher than other wavelength bands by a gas to be detected, and a second wavelength band in which infrared rays are absorbed less than the first wavelength band. Any filter may be used as long as it is a filter that allows one of the filters to be passed through, and is not limited to one that selects two filters. Instead of the first bandpass filter and the second bandpass filter, for example, a Fabry-Perot filter may be disposed on the optical path between the light source and the pyroelectric sensor, and the filter may be switched electrically.

  Although the embodiments of the present invention have been described above, the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, and includes meanings equivalent to the terms of the claims and all changes within the scope.

  DESCRIPTION OF SYMBOLS 1 Gas concentration detection apparatus, 10 1st housing, 11 Bottom part, 12 Perimeter wall part, 13 Maintenance opening part, 14 1st engaging part, 15 Inlet port, 16 Introducing hole, 17 Outlet hole, 20 2nd housing, 21 Frame portion, 22 transparent portion, 23 second engaging portion, 30 housing, 40 gas concentration detector, 42 circuit board, 44 optical path member, 44A guide portion, 46 communicating portion, 48 optical path portion, 50 light source, 54 focus Electrical sensor, 56 entrance window, 58 thermistor, 60 density detector, 62 switching device, 70 drive circuit, 72 amplifier circuit, 74 conversion circuit, 76 density conversion processing circuit, 78 switch drive circuit, 80 tubular member, 81 flange part, 82 introduction part, 83 lead-out part, 90 wind direction guide plate part, 100 duct, 101 through-hole, 110 LED, 120 button, 130 timer -, 200, 200A, 200B, 200C Calibration aid for gas concentration detector, 210, 210A, 210B, 210C Partition member, 211 First frame portion, 212 Second frame portion, 213 connection portion, 214 Absorbent support portion 215 opening, 220 absorbent.

Claims (11)

An optical path member having an infrared optical path therein and provided with a communication portion for communicating the optical path with an external space; an infrared irradiation element and an infrared light receiving element installed in the optical path; The measurement target gas introduced into the optical path is irradiated with infrared rays using the infrared irradiation element, and the measurement target gas is received by the infrared light reception element by receiving the infrared rays irradiated on the measurement target gas. A non-dispersive infrared absorption type gas concentration detector calibration method for detecting the concentration of a specific gas,
An absorbent that can absorb the specific gas and a cover member that can contain the absorbent are communicated to the optical path through the communicating portion, and the absorbent is external to the optical path member by the cover member. Attaching to the gas concentration detector so as to be separated from outside air at
Reducing the concentration of the specific gas in the optical path by maintaining the state where the cover member and the absorbent are attached to the gas concentration detector;
In a state where the concentration of the specific gas in the optical path is decreased, e Bei the step of calibrating the gas concentration detector,
The gas concentration detector is installed in a housing provided with an inlet through which the measurement target gas is introduced from the outside.
The housing includes a first housing provided with a maintenance opening and the gas concentration detector assembled thereto; and a second housing capable of opening and closing the maintenance opening.
Prior to attaching the absorbent and the cover member to the gas concentration detector, the method for calibrating the gas concentration detector further comprises a step of opening the maintenance opening . The gas concentration detector further includes a substrate portion on which the optical path member is mounted,
The cover member is constituted by a frame-shaped partition member having both ends opened, which is a member different from the housing, and a part of the second housing,
The step of attaching the absorbent and the cover member to the gas concentration detector causes the one end of the partition member to be in contact with the substrate portion, whereby the optical path member is moved by the partition member to the first housing. And a step of bringing the second housing into contact with the other open end of the partition member by closing the maintenance opening with the second housing. The gas concentration detector calibration method according to claim 1 . The gas concentration detector calibration method according to claim 2 , wherein the partition member is provided with an elastically deformable seal at the one end and the other end of the partition member that are opened. An optical path member having an infrared optical path therein and provided with a communication portion for communicating the optical path with an external space; an infrared irradiation element and an infrared light receiving element installed in the optical path; The measurement target gas introduced into the optical path is irradiated with infrared rays using the infrared irradiation element, and the measurement target gas is received by the infrared light reception element by receiving the infrared rays irradiated on the measurement target gas. A calibration aid for a gas concentration detector for calibrating a non-dispersive infrared absorption gas concentration detector that detects the concentration of a specific gas to be detected,
An absorbent capable of absorbing the specific gas;
A cover member capable of accommodating the absorbent,
The absorbent and the cover member are configured to detect the gas concentration so that the absorbent communicates with the optical path through the communication portion, and the absorbent is partitioned from the outside air by the cover member outside the optical path member. It can be attached to the device ,
The gas concentration detector is installed in a housing provided with an inlet through which the measurement target gas is introduced from the outside.
The housing includes a first housing provided with a maintenance opening and the gas concentration detector assembled thereto; and a second housing capable of opening and closing the maintenance opening.
The cover member is composed of a separate member from the housing, and is constituted by a partition member having a box shape with one end opened,
In the open state in which the second housing is removed and the maintenance opening is opened, the cover member is configured so that one end of the partition member contacts the first housing and covers the gas concentration detector. Calibration aid for gas concentration detector configured to be attachable to the housing . The gas concentration detector is installed in a housing provided with an inlet through which the measurement target gas is introduced from the outside.
The housing includes a first housing provided with a maintenance opening and the gas concentration detector assembled thereto; and a second housing capable of opening and closing the maintenance opening.
The cover member is composed of a separate member from the housing, and is constituted by a partition member having a box shape with one end opened,
The gas concentration detector further includes a substrate portion on which the optical path member is mounted,
The cover member is attached to the substrate portion so that one end of the partition member abuts the substrate portion and covers the optical path member when the second housing is removed and the maintenance opening is opened. The calibration aid for a gas concentration detector according to claim 4 , which is configured to be possible. The gas concentration detector is installed in a housing provided with an inlet through which the measurement target gas is introduced from the outside.
The housing includes a first housing provided with a maintenance opening and the gas concentration detector assembled thereto; and a second housing capable of opening and closing the maintenance opening.
The cover member is composed of a separate member from the housing, and is constituted by a partition member having a box shape with one end opened,
The gas concentration detector further includes a substrate portion on which the optical path member is mounted,
The cover member is attached to the optical path member so that one end of the partition member abuts on the optical path member and covers the communication portion in an opened state in which the second housing is removed and the maintenance opening is opened. The calibration aid for a gas concentration detector according to claim 4 , which is configured to be possible. The calibration aid for a gas concentration detector according to any one of claims 4 to 6 , wherein an elastically deformable seal portion is provided at the one end of the partition member having the box shape. The gas concentration detector is installed in a housing provided with an inlet through which the measurement target gas is introduced from the outside.
The housing includes a first housing provided with a maintenance opening and the gas concentration detector assembled thereto; and a second housing capable of opening and closing the maintenance opening.
The cover member is constituted by a frame-shaped partition member having both ends opened, which is a member different from the housing, and a part of the second housing,
In the open state in which the second housing is removed and the maintenance opening is opened, the frame-shaped partition member is brought into contact with the first housing at one open end of the frame-shaped partition member, The gas concentration detector is configured to be able to surround,
The frame-shaped partition member has an opening of the frame-shaped partition member in a closed state where the gas concentration detector is surrounded by the frame-shaped partition member and the second housing closes the maintenance opening. 5. The gas concentration detector calibration auxiliary tool according to claim 4 , wherein the other end is brought into contact with the second housing so as to be sandwiched and fixed between the first housing and the second housing. The gas concentration detector is installed in a housing provided with an inlet through which the measurement target gas is introduced from the outside.
The housing includes a first housing provided with a maintenance opening and the gas concentration detector assembled thereto; and a second housing capable of opening and closing the maintenance opening.
The cover member is constituted by a frame-shaped partition member having both ends opened, which is a member different from the housing, and a part of the second housing,
The gas concentration detector further includes a substrate portion on which the optical path member is mounted,
In the open state in which the second housing is removed and the maintenance opening is opened, the frame-shaped partition member is brought into contact with the substrate portion at one end where the frame-shaped partition member is opened. It is configured to be able to surround the optical path member,
The frame-shaped partition member may be configured by opening the frame-shaped partition member in a closed state in which the optical path member is surrounded by the frame-shaped partition member and the second housing closes the maintenance opening. 5. The gas concentration detector calibration auxiliary tool according to claim 4 , wherein an end is brought into contact with the second housing so as to be sandwiched and fixed between the substrate portion and the second housing. 6. The gas concentration detector is installed in a housing provided with an inlet through which the measurement target gas is introduced from the outside.
The housing includes a first housing provided with a maintenance opening and the gas concentration detector assembled thereto; and a second housing capable of opening and closing the maintenance opening.
The cover member is constituted by a frame-shaped partition member having both ends opened, which is a member different from the housing, and a part of the second housing,
The gas concentration detector further includes a substrate portion on which the optical path member is mounted,
In the open state in which the second housing is removed and the maintenance opening is opened, the frame-shaped partition member is brought into contact with the optical path member at an open end of the frame-shaped partition member. It is configured to be able to surround the communication part,
The frame-shaped partition member is configured by opening the frame-shaped partition member in a closed state in which the communication portion is surrounded by the frame-shaped partition member and the second housing closes the maintenance opening. 5. The gas concentration detector calibration auxiliary tool according to claim 4 , wherein an end is brought into contact with the second housing so as to be sandwiched and fixed between the optical path member and the second housing. 6. The gas concentration detector calibration assist according to any one of claims 8 to 10 , wherein an elastically deformable seal portion is provided at each of the one end and the other end of the frame-shaped partition member that are opened. Ingredients.

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