Inspection system for gas sensor module and inspection method for gas sensor module

Abstract

This inspection system 1 for a gas sensor module comprises: storage containers 6A-6C that each store an inspection gas therein; a chamber 31 that accommodates a gas sensor module 2 therein and into which the inspection gas is supplied from the storage containers 6A-6C; a gas supply device 33 that supplies the inspection gas; a gas discharge device 34 that returns the inspection gas to the storage containers 6A-6C; and a control device 4 that controls the gas supply device 33 and the gas discharge device 34. After the inspection of the gas sensor module 2 is completed, the control device 4 controls the gas discharge device 34 and returns the inspection gas in the chamber 31 into the storage containers 6A-6C.

Description

Gas Sensor Module Inspection System and Gas Sensor Module Inspection Method Cross-Reference to Related Applications

[0001] This application claims priority based on Japanese Patent Application No. 2025-049086 filed on March 24, 2025 (title of invention: "Gas Sensor Module Inspection System and Gas Sensor Module Inspection Method") and Japanese Patent Application No. 2025-049087 filed on March 24, 2025 (title of invention: "Gas Sensor Module Inspection System and Gas Sensor Module Inspection Method"). Furthermore, the contents of these Japanese patent applications are hereby fully incorporated herein by reference.

[0002] The present invention generally relates to a gas sensor module inspection system and a gas sensor module inspection method used in a production process of a gas sensor module, and more specifically relates to a gas sensor module inspection system and a gas sensor module inspection method that enable recovery and reuse of inspection gas used for inspecting a gas sensor module.

[0003] Conventionally, gas sensor modules mounted in gas detectors and the like have individual differences in performance characteristics (gas sensitivity, response characteristics, detection performance, etc.) due to manufacturing processes of the gas sensor module and non-uniformity of materials. Therefore, in the production process, inspections for calibration, adjustment, and operation confirmation are performed to correct individual differences and uniformize and standardize the performance characteristics of gas sensor modules. In addition, since variations may occur in the performance characteristics of gas sensor modules due to factors such as usage environment and aging, periodic implementation of inspections for calibration, adjustment, and operation confirmation is required as maintenance for the purpose of maintaining and restoring measurement accuracy. As an inspection method for a gas sensor module, a method is generally used in which a predetermined inspection gas is supplied to the gas sensor module to be inspected, after performance characteristics are confirmed, calibration and adjustment are performed as necessary, and finally an inspection for operation confirmation is carried out. For example, Patent Document 1 discloses a calibration apparatus for a gas detector using an inspection gas.

[0004] The calibration device described in Patent Document 1 performs calibration processing on the gas sensor module of a gas detector and has the function of adjusting the sensitivity of the gas sensor module by supplying a predetermined test gas into the gas detector. This calibration device comprises a gas storage container (such as a gas cylinder) for storing the test gas, a gas supply means for supplying the test gas, a gas supply channel for circulating the test gas to the object to be tested, and a discharge channel for exhausting the test gas to the outside of the calibration device after the calibration processing is completed. With this configuration, the test gas can be supplied to the gas sensor module to be calibrated, and calibration processing of the gas sensor module can be performed based on the detection value of the gas sensor module.

[0005] However, in the calibration apparatus described in Patent Document 1, the test gas used is exhausted to the outside each time the calibration process and inspection are completed. Therefore, the used test gas is recovered by a recovery means (recovery device, etc.) separate from the calibration apparatus described in Patent Document 1, subjected to detoxification treatment, and discarded without being reused. As a result, the amount of test gas remaining in the storage container decreases each time an inspection is performed, which creates the problem of incurring operational costs for replenishing the test gas.

[0006] Furthermore, from the perspective of reducing environmental impact, it is not appropriate to release the emitted test gases directly into the atmosphere; they must be treated to remove pollution before being released. In particular, when using fluorocarbon gases with high global warming potential as test gases, strict regulations are in place regarding gas emission, and appropriate treatment of the test gases is required to minimize environmental impact. However, implementing such appropriate treatment of test gases incurs significant costs, leading to the problem that the cost of treatment increases the overall cost of testing the gas sensor modules.

[0007] Japanese Patent Publication No. 2018-194351

[0008] This invention addresses the above-mentioned conventional problems and aims to provide a gas sensor module inspection system and a gas sensor module inspection method that enable the recovery and reuse of the inspection gas used to inspect the gas sensor module.

[0009] These objectives are achieved by the present invention as described in (1) and (2) below. (1) A gas sensor module inspection system comprising: a storage container for storing an inspection gas inside; a chamber in which a gas sensor module is housed and the inspection gas is supplied inside from the storage container; an air supply device provided between the storage container and the chamber for supplying the inspection gas from the storage container into the chamber; an exhaust device provided between the storage container and the chamber for returning the inspection gas in the chamber back into the storage container; and a control device for controlling the air supply device and the exhaust device, wherein the control device controls the air supply device and sets the environment inside the chamber to predetermined conditions to perform an inspection on the gas sensor module; and after the inspection on the gas sensor module is completed, the control device controls the exhaust device and returns the inspection gas in the chamber back into the storage container.

[0010] (2) A method for inspecting a gas sensor module, comprising the steps of: using an air supply device to supply an inspection gas from a storage container into a chamber in which a gas sensor module is housed, and setting the environment inside the chamber to predetermined conditions; using a control device to perform an inspection on the gas sensor module; and using an exhaust device to return the inspection gas in the chamber to the storage container.

[0011] According to the gas sensor module inspection system and gas sensor module inspection method of the present invention, the inspection gas can be recovered and reused without being discharged to the outside each time an inspection is performed. As a result, the consumption of inspection gas can be significantly reduced, and as a result, it is possible to eliminate the need to replenish the gas storage container with new inspection gas, or to significantly reduce the frequency of gas replenishment. This reduces the cost of continuous procurement of inspection gas and lowers the overall cost of inspecting gas sensor modules.

[0012] Furthermore, according to the gas sensor module inspection system and gas sensor module inspection method of the present invention, since the inspection gas can be recovered and reused after performing an inspection on the gas sensor module, the frequency of external discharge of the inspection gas can be significantly reduced. As a result, the number of times pollution treatment is performed on the inspection gas for disposal can be significantly reduced, and the overall cost of gas sensor module inspection can be significantly reduced. Moreover, by significantly reducing the frequency of external discharge of the inspection gas, it becomes easier to outsource pollution treatment to an external company, thus eliminating the need to introduce large-scale pollution treatment equipment that was conventionally required for gas sensor module inspection. As a result, the cost required for gas sensor module inspection can be significantly reduced.

[0013] Figure 1 is a diagram showing an inspection system for a gas sensor module according to an embodiment of the present invention. Figure 2 is a block diagram of a gas sensor module inspected by the inspection system shown in Figure 1. Figure 3 is a block diagram of a control device included in the inspection system shown in Figure 1. Figure 4 is a flowchart showing the inspection method for the gas sensor module of the present invention shown in Figure 1. Figure 5 is a flowchart showing the inspection method for the gas sensor module of the present invention shown in Figure 4 in more detail.

[0014] The following describes in detail, with reference to Figures 1 to 5, an inspection system and a method for inspecting a gas sensor module according to an embodiment of the present invention. Figure 1 is a diagram showing an inspection system for a gas sensor module according to an embodiment of the present invention. Figure 2 is a block diagram of a gas sensor module to be inspected by the inspection system shown in Figure 1. Figure 3 is a block diagram of a control device included in the inspection system shown in Figure 1. Figure 4 is a flowchart showing the inspection method for a gas sensor module according to the present invention shown in Figure 1. Figure 5 is a flowchart showing the inspection method for a gas sensor module according to the present invention shown in Figure 4 in more detail.

[0015] <Inspection System 1> The inspection system 1 for the gas sensor module of the present invention shown in Figure 1 (hereinafter also referred to as "inspection system 1") is used to perform inspections for the purpose of calibration, adjustment, and operational verification of the gas sensor module 2. The inspection system 1 includes a gas sensor module inspection device 3 (hereinafter also referred to as "inspection device 3") for performing inspections of the gas sensor module 2, a control device 4 for controlling the inspection device 3, gas cylinders 5A, 5B, 5C, and 5D which are sources of inspection gas or nitrogen gas used in the inspection of the gas sensor module 2, storage containers 6A, 6B, and 6C for storing the inspection gas inside, valves 7A, 7B, and 7C which are provided between the gas cylinders 5A to 5D and the storage containers 6A to 6C respectively and which can be opened and closed by electrical signals, and a detoxification device 8 for performing detoxification treatment on the inspection gas discharged from the inspection device 3. Here, the test gas includes a standard gas stored in storage container 6A, a low-concentration gas stored in storage container 6B, and a high-concentration gas stored in storage container 6C.

[0016] <Gas Sensor Module 2> The gas sensor module 2 is installed in any device and detects the presence or concentration of a gas to be detected in the surrounding atmosphere where the device is installed. When it is determined that the gas to be detected is present at a concentration (threshold) above a predetermined level, the gas sensor module 2 has the function of notifying of an abnormality by emitting an alarm signal indicating that the concentration of the gas to be detected in the atmosphere in which the gas sensor module 2 is placed is above a predetermined threshold and an alarm should be issued. The gas sensor module 2 is configured to output a concentration signal indicating the concentration of the gas to be detected in the atmosphere in which the gas sensor module 2 is placed, an alarm signal indicating that the concentration of the gas to be detected is above a predetermined threshold 253 (see Figure 2) and an alarm should be issued when the concentration of the gas to be detected is above a predetermined threshold 253, and an alarm signal indicating that the concentration of the gas to be detected is below a predetermined threshold 253 and that it is normal when the concentration of the gas to be detected is below a predetermined threshold 253. The device in which the gas sensor module 2 is installed receives the alarm signal or the normal signal from the gas sensor module 2 at a predetermined frequency. When the device receives an alarm signal from the gas sensor module 2, the device performs a predetermined warning action using any alarm means. The alarm means may include, for example, an alarm using sound such as an alarm sound or voice, an alarm using light such as an LED lighting, or an alarm using vibration with a vibration function.

[0017] In the inspection system 1 according to the present invention, the gas sensor module 2 is housed in the chamber 31 of the inspection device 3 and mounted on an inspection circuit board 32 provided in the chamber 31. Subsequently, the inspection device 3 is controlled by the control device 4, and the first calibration and second calibration of the gas sensor module 2, as described later, are sequentially performed. If an error exceeding a predetermined tolerance range (for example, ±500 ppm) is detected in the output value of the gas sensor module 2 during these calibration processes, calibration and adjustment are performed on the gas sensor module 2. After the completion of calibration and adjustment, an operational verification test is performed to determine whether the gas sensor module 2 appropriately outputs an alarm signal when the concentration of the detected gas exceeds a predetermined threshold 253. This series of inspection processes ensures the performance and reliability of the gas sensor module 2.

[0018] In this embodiment, the gas sensor module 2 is configured to detect the concentration of difluoromethane (R32), an HFC refrigerant used as a fluorocarbon refrigerant, as the concentration of the gas to be detected. The following explanation is provided assuming this configuration. However, the gas to be detected is not limited to R32, but may be other fluorocarbon refrigerants. Furthermore, the gas to be detected is not limited to fluorocarbon refrigerants, but may be carbon dioxide, carbon monoxide, propane, methane, butane, ammonia, oxygen disulfide, nitrogen dioxide, nitric oxide, ozone, sulfur hexafluoride, ethylene, etc.

[0019] As shown in Figure 2, the gas sensor module 2 includes one or more processors 21 for controlling the gas sensor module 2, an I / O (input / output) interface 22 for input to and output from the gas sensor module 2, a gas detection means 23 for detecting the concentration of the gas to be detected, and one or more memories 24 that store data 25 and modules 26 used to perform processing of the gas sensor module 2.

[0020] One or more processors 21 function as the control unit for the gas sensor module 2. The one or more processors 21 are arithmetic units that execute arithmetic processing such as signal manipulation based on computer-readable instructions, such as one or more microprocessors, microcomputers, microcontrollers, digital signal processors (DSPs), central processing units (CPUs), memory control units (MCUs), graphics processing units (GPUs), state machines, logic circuits, application-specific integrated circuits (ASICs), or combinations thereof. In particular, the processors 21 are configured to fetch computer-readable instructions (e.g., data, programs, modules, etc.) stored in the memory 24 and to execute arithmetic, signal manipulation, and overall control processing of the gas sensor module 2. Furthermore, the processors 21 are configured to control the gas sensor module 2 and perform gas detection operations in response to control from the control device 4. For example, the processor 21 uses a gas concentration calculation module 262 (described later) to perform calculations on the detection signal received from the gas detection means 23 using the output value calculation formula 251 and correction coefficient 252 stored in the memory 24 to calculate the concentration of the detected gas. The processor then outputs a concentration signal indicating the calculated concentration of the detected gas, along with either an alarm signal or a normal signal, to the control device 4 via the I / O interface 22. Specifically, if the calculated concentration of the detected gas is greater than or equal to a threshold value 253 stored in the memory 24, the processor 21 outputs an alarm signal along with the concentration signal to the control device 4. On the other hand, if the calculated concentration of the detected gas is less than the threshold value 253, the processor 21 outputs a normal signal along with the concentration signal to the control device 4.

[0021] The I / O interface 22 is provided for input from an external device to the gas sensor module 2 and output from the gas sensor module 2 to an external device. In the inspection system 1 according to the present invention, a control signal is input from the control device 4 to the processor 21 via the I / O interface 22, and further, a concentration signal obtained by processing the detection signal of the gas detection means 23, and either an alarm signal or a normal signal are output to the control device 4. The I / O interface 22 includes various software interfaces and hardware interfaces such as a web interface and a graphical user interface (GUI). For example, the I / O interface 22 is an interface for peripheral devices such as a keyboard, mouse, touch panel display, external memory, printer, and display. The I / O interface 22 enables input to the gas sensor module 2 using input devices such as a keyboard, mouse, and touch panel display, and output from the gas sensor module 2 to a display, printer, and external memory. The I / O interface 22 may also enable the gas sensor module 2 to communicate with any external device such as a web server or data server located outside via a network such as the Internet.

[0022] The gas detection means 23 is specifically a gas sensor that measures the concentration of a predetermined gas to be detected and outputs a detection signal to the processor 21 corresponding to the concentration of the gas to be detected. The detection method of the gas detection means 23 can be any appropriate method corresponding to the type of gas to be detected, such as an optical method (non-dispersive infrared absorption method: NDIR method, or photoacoustic method: PA method), a semiconductor method, a tunable semiconductor laser absorption spectroscopy (TDLAS) method, or an electrochemical method. For example, if the gas detection means 23 is an optical gas sensor, the gas detection means 23 includes a light source that emits infrared rays and a light receiving unit which is an infrared sensor (IR sensor) that receives the infrared rays emitted from the light source.

[0023] The memory 24 is a computer-readable medium including volatile storage media (e.g., RAM, SRAM, DRAM), non-volatile storage media (e.g., ROM, EPROM, EEPROM, flash memory, hard disk, optical disc, CD-ROM, digital multipurpose disc (DVD), Blu-ray disc, magnetic cassette, magnetic tape, magnetic disk), or a combination thereof.

[0024] Memory 24 is communicatively connected to the processor 21 and stores data 25 necessary for the gas sensor module 2 to perform processing, as well as multiple modules 26 that can be executed by the processor 21. Memory 45 also has a function to temporarily store data received, processed, and generated by one or more of the multiple modules 26, as well as data necessary to perform processing by the multiple modules 26.

[0025] The data 25 stored in the memory 24 includes an output value calculation formula 251 for calculating the concentration of the detected gas based on the detection signal received from the gas detection means 23, a correction coefficient 252 which is one or more coefficients and constant terms used in the output value calculation formula 251, a threshold 253 for determining whether to output an alarm signal or a normal signal based on the concentration of the detected gas calculated using the output value calculation formula 251 and the correction coefficient 252, and any number of other data 254 necessary to perform processing of the gas sensor module 2.

[0026] The output value calculation formula 251 is a gas concentration calculation formula for calculating the concentration of the detected gas based on the detection signal received from the gas detection means 23. The output value calculation formula 251 is a higher-order equation in which the value of the detection signal received from the gas detection means 23 is a variable. In one example, the output value calculation formula 251 is a fourth-order equation (ax ４ +bx ３ +cx ２ (x + dx + e), in which case x is the value of the detection signal received from the gas detection means 23.

[0027] The correction coefficient 252 is the coefficient and constant term used in the output value calculation formula 251 described above. In the example of the quartic equation above, the coefficients a, b, c, d and the constant term e of the quartic equation are the correction coefficient 252. The correction coefficient 252 can be overwritten by the control device 4, and by performing the first calibration and the second calibration described later, an appropriate correction coefficient 252 is transmitted from the control device 4 to the gas sensor module 2 and stored in the memory 24. When an appropriate correction coefficient 252 is stored in the memory 24, when calculating the concentration of the detected gas based on the detection signal received from the gas detection means 23, the output value calculation formula 251 and the correction coefficient 252 can be used to correct for variations in the output value due to individual differences in the gas detection means 23. This makes it possible to equalize the detection accuracy of the gas sensor module 2.

[0028] The threshold value 253 is a predetermined fixed value used by the gas sensor module 2 to determine whether to output an alarm signal or a normal signal based on the concentration of the detected gas calculated using the output value calculation formula 251 and the correction coefficient 252. When the calculated concentration of the detected gas is greater than or equal to the threshold value 253, the gas sensor module 2 outputs a concentration signal indicating the calculated concentration of the detected gas and an alarm signal indicating that the calculated concentration of the detected gas is greater than or equal to the threshold value 253 and an alarm should be issued, via the I / O interface 22. On the other hand, when the calculated concentration of the detected gas is less than the threshold value 253, the gas sensor module 2 outputs a concentration signal indicating the calculated concentration of the detected gas and a normal signal indicating that the calculated concentration of the detected gas is less than the threshold value 253 and is normal, via the I / O interface 22. In this embodiment, the threshold value 253 is set to 10,000 ppm.

[0029] Module 26 is a computer-readable instruction executable by the processor 21, such as a routine, application, program, algorithm, library, object, component, data structure, or combination thereof. Module 26 includes a gas detection means control module 261, a gas concentration calculation module 262, an alarm determination module 263, and any number of other modules 264 to complement the functions provided by the gas sensor module 2.

[0030] The gas detection means control module 261 has the function of driving the gas detection means 23 and acquiring a detection signal from the gas detection means 23 according to the concentration of the gas to be detected in the atmosphere in which the gas sensor module 2 is installed. The acquired detection signal is temporarily stored in the memory 24 and used to calculate the concentration of the gas to be detected.

[0031] The gas concentration calculation module 262 has the function of calculating the concentration of the detected gas using the detection signal from the gas detection means 23 temporarily stored in the memory 24, and the output value calculation formula 251 and correction coefficient 252 that are pre-stored in the memory 24. The gas concentration calculation module 262 uses the value of the detection signal from the gas detection means 23 as a variable, and the correction coefficient 252 as a coefficient and constant term, and calculates the concentration of the detected gas based on the output value calculation formula 251. The calculated concentration value of the detected gas is temporarily stored in the memory 24 and output externally as a concentration signal.

[0032] The alarm determination module 263 compares the concentration value of the detected gas calculated by the gas concentration calculation module 262 with a threshold value 253 (10,000 ppm in this embodiment) stored in the memory 24 to determine whether to output an alarm signal or a normal signal. Specifically, if the calculated concentration value of the detected gas is less than the threshold value 253, the alarm determination module 263 determines that a normal signal should be output and generates a normal signal. On the other hand, if the calculated concentration of the detected gas is greater than or equal to the threshold value 253, the alarm determination module 263 determines that an alarm signal should be output and generates an alarm signal. The alarm signal or normal signal generated by the alarm determination module 263 is temporarily stored in the memory 24 and output to the processor 21. Subsequently, the processor 21 outputs either the alarm signal or the normal signal stored in the memory 24 to the outside, along with the concentration signal temporarily stored in the memory 24.

[0033] <Inspection device 3> Returning to Figure 1, inspection device 3 is used to perform inspections on the gas sensor module 2 in response to control from the control device 4. Hereinafter, the gas to be detected used in inspection device 3 will be referred to as the "inspection gas". R32 (standard gas, low-concentration gas, and high-concentration gas) that has been appropriately diluted to a predetermined concentration is used as the inspection gas. The inspection device 3 includes a chamber 31 that houses a gas sensor module 2, an inspection circuit board 32 provided inside the chamber 31 on which the gas sensor module 2 is mounted during inspection, an air supply device 33 for supplying inspection gas and nitrogen gas into the chamber 31, an exhaust device 34 for exhausting the inspection gas and nitrogen gas from inside the chamber 31, a gas sensor 35A, a pressure sensor 35B, a humidity sensor 35C, and a temperature sensor 35D for measuring the environment (atmosphere) inside the chamber 31, a controller 36 for controlling the air supply device 33 and the exhaust device 34 in accordance with control from the control device 4, an air supply valve 37A provided in the flow path between the chamber 31 and the air supply device 33, an exhaust valve 37B provided in the flow path between the chamber 31 and the exhaust device 34, and valves 37C and 37D provided in the flow path connecting the chamber 31 to a sealed space (not shown) in which the gas sensor 35A is housed. The air intake valve 37A, the exhaust valve 37B, and the valves 37C and 37D are electromagnetic valves that open and close electromagnetically in response to control from the controller 36.

[0034] Chamber 31 is a sealable container that houses the gas sensor module 2 to be inspected during inspection. Chamber 31 includes an air inlet (not shown) that allows the supply of inspection gas or nitrogen gas into Chamber 31, and an exhaust port (not shown) that allows the exhaust of gas from inside Chamber 31. The air inlet of Chamber 31 is connected to an air supply device 33 via a flow path equipped with an air supply valve 37A. The exhaust port of Chamber 31 is connected to an exhaust device 34 via a flow path equipped with an exhaust valve 37B. The air supply valve 37A also functions as a check valve that allows the one-way flow of gas from the air supply device 33 to Chamber 31. Similarly, the exhaust valve 37B also functions as a check valve that allows the one-way flow of gas from inside Chamber 31 to the exhaust device 34.

[0035] The inspection circuit board 32 is located inside the chamber 31. The inspection circuit board 32 is mounted on a gas sensor module 2, and the control device 4 is further connected to the inspection circuit board 32 in a communication manner. Signals from the control device 4 are transmitted to the gas sensor module 2 via the inspection circuit board 32, and the concentration signal from the gas sensor module 2, along with either an alarm signal or a normal signal, is transmitted to the control device 4. The inspection circuit board 32 is connected to the control device 4 in a wired or wireless communication manner. In the illustrated configuration, the inspection circuit board 32 is connected to the control device 4 in a wired communication manner by a cable 48, but the present invention is not limited to this. The inspection circuit board 32 may also be connected to the control device 4 in a wireless communication manner. Furthermore, the inspection circuit board 32 is connected to each of the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D in a wired or wireless communication manner. Therefore, detection signals related to the environment (atmosphere) inside the chamber 31, output from the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D, are transmitted to the control device 4 via the inspection circuit board 32.

[0036] The air supply device 33 is installed between the storage containers 6A to 6C and the gas cylinder 5D for nitrogen gas and the chamber 31, and is a device for supplying test gas or nitrogen gas from the storage containers 6A to 6C and the gas cylinder 5D into the chamber 31. The air supply device 33 is equipped with valves 33A, 33B, 33C, and 33D for switching the flow path (piping) through which the test gas is supplied.

[0037] Valves 33A to 33D are electromagnetic valves that open and close electromagnetically in response to control from the controller 36. Valves 33A to 33D are electrically connected to the controller 36, and their open and closed states are controlled by the controller 36. By appropriately switching the open and closed states of valves 33A to 33D, the flow path through which the inspection gas is transported can be selectively changed. This makes it possible to select the inspection gas supplied into the chamber 31.

[0038] Valve 33A is located in the flow path connecting the air supply valve 37A and the storage container 6A, and opens and closes the flow path between the storage container 6A and the chamber 31. Valve 33A also functions as a check valve that allows the one-way inflow of standard gas from the storage container 6A to the air supply device 33. By opening both valve 33A and the air supply valve 37A, the flow path between the storage container 6A and the chamber 31 is opened, allowing the supply of test gas from the storage container 6A into the chamber 31. Valve 33B is located in the flow path connecting the air supply valve 37A and the storage container 6B, and opens and closes the flow path between the storage container 6B and the chamber 31. Valve 33B also functions as a check valve that allows the one-way inflow of low-concentration gas from the storage container 6B to the air supply device 33. By opening both valve 33B and the air supply valve 37A, the flow path between the storage container 6B and the chamber 31 is opened, allowing the inspection gas to be supplied from the storage container 6B into the chamber 31. Valve 33C is provided in the flow path connecting the air supply valve 37A and the storage container 6C, and opens and closes the flow path between the storage container 6C and the chamber 31. Valve 33C also functions as a check valve that allows the one-way inflow of high-concentration gas from the storage container 6C to the air supply device 33. By opening both valve 33C and the air supply valve 37A, the flow path between the storage container 6C and the chamber 31 is opened, allowing the inspection gas to be supplied from the storage container 6C into the chamber 31. Valve 33D is provided in the flow path connecting the air supply valve 37A and the gas cylinder 5D, and opens and closes the flow path between the gas cylinder 5D and the chamber 31. Valve 33D also functions as a check valve that allows for the one-way flow of nitrogen gas from the gas cylinder 5D to the air supply device 33. By opening both valve 33D and the air supply valve 37A, the flow path between the gas cylinder 5D and the chamber 31 is opened, allowing nitrogen gas to be supplied from the gas cylinder 5D into the chamber 31. The controller 36 controls valves 33A to 33D so that only one of the valves 33A to 33D is open and the rest are closed. In other words, the controller 36 does not control valves 33A to 33D to be open two or more at the same time.

[0039] The exhaust device 34 is installed between the storage containers 6A to 6C and the abatement device 8 and the chamber 31. The exhaust device 34 has the function of returning the test gas in the chamber 31 to the corresponding storage containers 6A to 6C, and also the function of transferring the test gas from the chamber 31 to the abatement device 8 when the test gas in the chamber 31 is to be discarded. Furthermore, the exhaust device 34 has the function of releasing clean air or nitrogen gas that does not contain the test gas in the chamber 31 into the atmosphere. The exhaust device 34 includes valves 34A, 34B, 34C, 34D, and 34E for switching the flow path for exhausting the gas in the chamber 31, and a pump 341 for exhausting the gas in the chamber 31, communicating with the chamber 31 via the exhaust valve 37B, and reducing the pressure inside the chamber 31.

[0040] Valves 34A to 34E are electromagnetic valves that open and close electromagnetically in response to control from the controller 36. Valves 34A to 34E are electrically connected to the controller 36, and their open and closed states are controlled by the controller 36. By appropriately switching the open and closed states of valves 34A to 34E, the flow path through which the test gas is transported can be selectively changed. This makes it possible to return (recover) the test gas discharged from the chamber 31 to specific storage containers 6A to 6C.

[0041] Valve 34A is located in the flow path connecting pump 341 and storage container 6A, and opens and closes the flow path between pump 341 and storage container 6A. Valve 34A also functions as a check valve that allows the one-way inflow of standard gas from exhaust device 34 to storage container 6A. By opening both valve 34A and exhaust valve 37B, the flow path between storage container 6A and chamber 31 is opened, making it possible to return the test gas in chamber 31 to storage container 6A. Valve 34B is located in the flow path connecting pump 341 and storage container 6B, and opens and closes the flow path between pump 341 and storage container 6B. Valve 34B also functions as a check valve that allows the one-way inflow of low-concentration gas from exhaust device 34 to storage container 6B. By opening both valve 34B and exhaust valve 37B, the flow path between the storage container 6B and the chamber 31 is opened, allowing the test gas in the chamber 31 to be returned to the storage container 6B. Valve 34C is provided in the flow path connecting the pump 341 and the storage container 6C, and opens and closes the flow path between the pump 341 and the storage container 6C. Valve 34C also functions as a check valve that allows the one-way inflow of high-concentration gas from the exhaust device 34 to the storage container 6C. By opening both valve 34C and exhaust valve 37B, the flow path between the storage container 6C and the chamber 31 is opened, allowing the test gas in the chamber 31 to be returned to the storage container 6C. Valve 34D is provided in the flow path connecting the pump 341 and the abatement device 8, and opens and closes the flow path between the pump 341 and the abatement device 8. Valve 34D also functions as a check valve that allows the inspection gas to flow unilaterally from the exhaust device 34 to the abatement device 8. By opening both valve 34D and the exhaust valve 37B, the flow path between the abatement device 8 and the chamber 31 is opened, making it possible to transfer the inspection gas in the chamber 31 to the abatement device 8. Valve 34E is provided in the flow path that connects the pump 341 to the exhaust port of the exhaust device 34 for releasing the gas in the chamber 31 into the atmosphere. Valve 34E also functions as a check valve that allows the gas to flow unilaterally out of the exhaust port of the exhaust device 34 into the atmosphere.By opening both valve 34E and exhaust valve 37B, the flow path between the exhaust port and the chamber 31 is opened, allowing the gas inside the chamber 31 to be released to the outside. The controller 36 controls valves 34A to 34E so that only one of the valves 34A to 34E is open and the rest are closed. In other words, the controller 36 does not control valves 34A to 34E to be open two or more at the same time.

[0042] The pump 341 has a function of reducing the pressure in the chamber 31 by exhausting the gas in the chamber 31. Specifically, the pump 341 is an exhaust pump such as a decompression pump or a vacuum pump that can bring the environment inside the chamber 31 into a decompressed state. Preferably, a vacuum pump capable of bringing the environment inside the chamber 31 into a vacuum state can be used as the pump 341. The pump 341 continues to operate constantly during the operation of the inspection apparatus 3. Therefore, when the controller 36 closes the valves 33A to 33D and the air supply valve 37A, and further opens one of the valves 34A to 34E and the exhaust valve 37B in accordance with control from the control apparatus 4, the gas in the chamber 31 is exhausted, the pressure in the chamber 31 decreases, and the environment inside the chamber 31 becomes a decompressed state, preferably a vacuum state. Further, in a decompressed state where the pressure in the chamber 31 is reduced, or in a state where the environment inside the chamber 31 is brought into a vacuum state, when the controller 36 closes the exhaust valve 37B and opens one of the valves 33A to 33D and the air supply valve 37A in accordance with control from the control apparatus 4, a pressure difference is generated between the pressure in the chamber 31 and the pressure in the storage containers 6A to 6C or the gas cylinder 5D. As a result, the inspection gas or nitrogen gas can be supplied into the chamber 31 by utilizing the pressure difference between the pressure in the chamber 31 and the pressure in the storage containers 6A to 6C or the gas cylinder 5D. As described above, since the pump 341 of the exhaust device 34 is used for both supplying the inspection gas or nitrogen gas into the chamber 31 and exhausting the gas in the chamber 31, it is not necessary to provide additional power such as an air supply pump in the air supply device 33. As a result, the inspection apparatus 3 can be simplified, and the introduction cost and maintenance cost of the inspection apparatus 3 can be reduced.

[0043] The gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D are sensors that measure various parameters (concentration, pressure, humidity, and temperature of the test gas) inside the chamber 31, and are used to confirm whether the environment (atmosphere) inside the chamber 31 meets predetermined measurement conditions. Each of the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D is connected to the test circuit board 32 via wired or wireless communication, and the detection signals from each of the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D are transmitted to the control device 4 via the test circuit board 32. The measurement conditions for setting the predetermined atmosphere are stored in advance in the memory 45 of the control device 4 as the first calibration condition 461, the second calibration condition 462, the first inspection condition 463, and the second inspection condition 464, which will be described later.

[0044] The gas sensor 35A is housed in a sealed space (not shown) that communicates with the chamber 31 via valves 37C and 37D. Valve 37C also functions as a check valve that allows the one-way flow of gas from the chamber 31 into the sealed space. On the other hand, valve 37D also functions as a check valve that allows the one-way flow of gas from the sealed space into the chamber 31. When valve 37C is opened and valve 37D is closed by the controller 36, the gas sensor 35A is exposed to the test gas supplied from the chamber 31, starts measuring the concentration of the test gas, and outputs a detection signal to the control device 4 via the test circuit board 32. After measuring the concentration of the test gas, when valve 37C is closed and valve 37D is opened by the controller 36, and the pressure in the chamber 31 is reduced by the exhaust device 34, the test gas supplied to the sealed space where the gas sensor 35A is located is discharged (returned) to the chamber 31.

[0045] The controller 36 is a programmable logic controller (PLC), and opens and closes the valves 33A to 33D, valves 34A to 34E, air supply valve 37A, exhaust valve 37B, valves 37C, 37D, and valves 7A to 7C in the inspection device 3 in accordance with control from the control device 4 using a predefined program or the like.

[0046] The controller 36 closes the valves 33A to 33D and the air supply valve 37A, and further opens one of the valves 34A to 34C and the exhaust valve 37B in accordance with control from the control device 4, thereby selectively returning the inspection gas in the chamber 31 to any one of the storage containers 6A to 6C and reducing the pressure in the chamber 31 (bringing the chamber into a decompressed state). At this time, if the pump 341 of the exhaust device 34 is a vacuum pump, the inside of the chamber 31 can be brought into a vacuum state. In the decompressed state where the pressure in the chamber 31 has been reduced, the controller 36 closes the valves 34A to 34E of the exhaust device 34 and the exhaust valve 37B, and further opens one of the valves 33A to 33C and the air supply valve 37A in accordance with control from the control device 4. At this time, a desired inspection gas is supplied into the chamber 31 by utilizing the differential pressure between the pressure in the chamber 31 and the pressure in any one of the storage containers 6A to 6C whose flow path communicating with the chamber 31 is opened.

[0047] The control device 4 receives detection signals from the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D via the inspection circuit board 32, regarding various parameters within the chamber 31 (concentration, pressure, humidity, and temperature of the test gas). From the received detection signals, the control device 4 determines whether the environment within the chamber 31 is set to a predetermined condition (i.e., one of the first calibration condition 461, the second calibration condition 462, the first inspection condition 463, and the second inspection condition 464). If the environment within the chamber 31 is set to a predetermined condition, the control device 4 performs calibration or inspection on the gas sensor module 2 installed in the chamber 31. On the other hand, if the environment within the chamber 31 is not set to a predetermined condition, the control device 4, via the controller 36, performs exhaust from the chamber 31 and supply air to the chamber 31 again to set the environment within the chamber 31 to a predetermined condition.

[0048] <Control device 4> The control device 4 controls the operation of the inspection device 3 via the controller 36 and receives a concentration signal and either an alarm signal or a normal signal from the gas sensor module 2 via the inspection circuit board 32. Specifically, the control device 4 is connected to the controller 36 and the inspection circuit board 32 on which the gas sensor module 2 of the inspection device 3 is mounted, either by wire or wireless communication, and is configured to communicate with the controller 36 and the inspection circuit board 32 using a predetermined protocol. The control device 4 is, for example, a personal computer (PC) of the desktop, notebook, or tablet type.

[0049] As shown in Figure 3, the control device 4 includes a processor 41 that controls the control device 4, an I / O interface 42 for performing inputs to and outputs from the control device 4, an operation unit 43 used for input operations, a display unit 44 for displaying arbitrary information, and one or more memories 45 that store data 46 and modules 47 used to perform processing of the control device 4.

[0050] The processor 41 is an arithmetic unit that performs arithmetic processing such as signal manipulation based on computer-readable instructions such as one or more microprocessors, microcomputers, microcontrollers, digital signal processors (DSPs), central processing units (CPUs), memory control units (MCUs), graphics processing units (GPUs), state machines, logic circuits, application-specific integrated circuits (ASICs), or combinations thereof. In particular, the processor 41 is configured to fetch computer-readable instructions (e.g., data, programs, modules, etc.) stored in the memory 45 and to perform arithmetic, signal manipulation, and control.

[0051] The I / O interface 42 includes various software interfaces and hardware interfaces, such as a web interface and a graphical user interface (GUI). For example, the I / O interface 42 is an interface for peripheral devices such as a keyboard, mouse, touch panel display, external memory, printer, and display. The I / O interface 42 enables input to the control device 4 using input devices such as a keyboard, mouse, and touch panel display, and output from the control device 4 to a display, printer, and external memory. The I / O interface 42 may also enable the control device 4 to communicate with any external device, such as a web server or data server located outside the device, via a network such as the Internet.

[0052] The operation unit 43 is an input device that receives input from users using the inspection system 1. The operation unit 43 is not particularly limited and can include, for example, a keyboard or a mouse.

[0053] The display unit 44 is a display means for displaying arbitrary information. For example, the display unit 44 can display the concentration signal received from the gas sensor module 2, that is, the concentration value of the detected gas, and whether an alarm signal or a normal signal was received. Users of the inspection system 1 can confirm the calibration and inspection results for the gas sensor module 2 by looking at the display unit 44. The display unit 44 is not particularly limited and can be made of, for example, liquid crystal, organic EL, etc. Furthermore, the operation unit 43 and the display unit 44 may be made of a touch panel in which a touch sensor and a display are integrated.

[0054] The memory 45 is a computer-readable medium including volatile storage media (e.g., RAM, SRAM, DRAM), non-volatile storage media (e.g., ROM, EPROM, EEPROM, flash memory, hard disk, optical disc, CD-ROM, digital multipurpose disc (DVD), Blu-ray disc, magnetic cassette, magnetic tape, magnetic disk), or a combination thereof.

[0055] The memory 45 is connected to the processor 41 in a communicative manner and stores data 46 necessary for the control device 4 to execute processing, as well as multiple modules 47 that can be executed by the processor 41. The memory 45 also has a function to temporarily store data received, processed, and generated by one or more of the multiple modules 47, as well as data necessary to execute processing by the multiple modules 47.

[0056] The data 46 stored in memory 45 includes a first calibration condition 461 for performing a first calibration, a second calibration condition 462 for performing a second calibration, a first inspection condition 463 for performing a first inspection, a second inspection condition 464 for performing a second inspection, and any number of other data 465 necessary for performing the processing of the control device 4.

[0057] The first calibration condition 461 is the condition for performing a first calibration on the gas sensor module 2 housed in the chamber 31 of the inspection device 3. The first calibration is performed to receive the concentration signal output from the gas sensor module 2 in an atmosphere that does not contain the inspection gas (R32 in this embodiment), and to calculate a correction coefficient 252, more specifically, the constant term e in the case of the above-described quartic equation, for correcting the concentration value of the inspection gas to an appropriate value. The first calibration condition 461 includes the gas concentration, pressure, humidity, and temperature that the environment inside the chamber 31 must satisfy in the first calibration. Hereinafter, the environment that satisfies the first calibration condition 461 will also be referred to as a "clean air atmosphere". Here, clean air is air that does not contain the inspection gas (R32 in this embodiment), and in this embodiment, nitrogen gas is used. In one example, the first calibration condition 461 requires that the environment inside the chamber 31 has a gas concentration of 500 ppm or less, preferably 0.00 ppm; a pressure of 0.99 atmospheres or more and 1.01 atmospheres or less, preferably 1.00 atmospheres; a temperature of 20 degrees Celsius or more and 30 degrees Celsius or less, preferably 25 degrees Celsius; and a humidity of 30% or less, preferably 0%. In this embodiment of the inspection system 1, the chamber 31 is filled only with nitrogen gas supplied from the gas cylinder 5D, thereby achieving a state where the chamber 31 is filled with clean air. The control device 4 controls the gas sensor module 2 to measure the concentration of the inspection gas when the environment inside the chamber 31 is set to the first calibration condition 461, and calculates a correction coefficient 252 (offset coefficient) to correct the value of the inspection gas concentration to zero (zero point adjustment) from the concentration signal received from the gas sensor module 2, i.e., the value of the inspection gas concentration. Subsequently, the control device 4 transmits the calculated correction coefficient 252 to the gas sensor module 2 via the test circuit board 32, and the gas sensor module 2 updates the correction coefficient 252 stored in the memory 24 based on the correction coefficient 252 received from the control device 4.

[0058] The second calibration condition 462 is the condition for performing a second calibration on the gas sensor module 2 housed in the chamber 31 of the inspection device 3. The second calibration is performed to receive the concentration signal output from the gas sensor module 2 under the atmosphere of a known concentration of test gas (standard gas) and to calculate a correction coefficient 252, more specifically, coefficients a to d in the case of the above-mentioned quartic equation, for correcting the concentration value of the test gas to an appropriate value. The second calibration condition 462 includes the gas concentration, pressure, humidity, and temperature that the environment inside the chamber 31 must satisfy in the second calibration. Hereinafter, the environment that satisfies the second calibration condition 462 will also be referred to as the "standard concentration atmosphere". In one example, the second calibration condition 462 requires that the environment inside the chamber 31 has a gas concentration of 9500 ppm or more and 10500 ppm or less, preferably 10000 ppm; a pressure of 0.99 atmospheres or more and 1.01 atmospheres or less, preferably 1.00 atmospheres; a temperature of 20 degrees or more and 30 degrees or less, preferably 25 degrees; and a humidity of 30% or less, preferably 0%. The control device 4 controls the gas sensor module 2 to measure the concentration of the test gas when the environment inside the chamber 31 is set to the second calibration condition 462, and calculates a correction coefficient 252 (gain coefficient) for adjusting the sensitivity of the gas sensor module 2 from the concentration signal received from the gas sensor module 2, i.e., the value of the test gas concentration. Subsequently, the control device 4 transmits the calculated correction coefficient 252 to the gas sensor module 2 via the test circuit board 32, and the gas sensor module 2 updates the correction coefficient 252 stored in the memory 24 based on the correction coefficient 252 received from the control device 4.

[0059] The first inspection condition 463 is the condition for performing a first inspection on the gas sensor module 2 housed in the chamber 31 of the inspection device 3. The first inspection is performed to confirm whether the gas sensor module 2 outputs a normal signal in an atmosphere where the concentration of the test gas is less than a threshold 253. The first inspection condition 463 includes the gas concentration, pressure, humidity, and temperature that the environment inside the chamber 31 must satisfy in the first inspection. The environment that satisfies the first inspection condition 463 is also hereinafter referred to as the "low-concentration inspection atmosphere". In one example, the first inspection condition 463 requires that the environment inside the chamber 31 has a gas concentration of 5630 ppm or more and 6630 ppm or less, preferably 6130 ppm; a pressure of 0.99 atmospheres or more and 1.01 atmospheres or less, preferably 1.00 atmospheres; a temperature of 20 degrees or more and 30 degrees or less, preferably 25 degrees; and a humidity of 30% or less, preferably 0%.

[0060] The second inspection condition 464 is the condition for performing a second inspection on the gas sensor module 2 housed in the chamber 31 of the inspection device 3. The second inspection is performed to confirm whether the gas sensor module 2 outputs an alarm signal in an atmosphere where the concentration of the test gas is 253 or higher than a threshold value. The second inspection condition 464 includes the gas concentration, pressure, humidity, and temperature that the environment inside the chamber 31 must satisfy in the second inspection. The environment that satisfies the second inspection condition 464 is also hereinafter referred to as the "high-concentration inspection atmosphere". In one example, the second inspection condition 464 requires that the environment inside the chamber 31 has a gas concentration of 13370 ppm or more and 14370 ppm or less, preferably 13870 ppm; a pressure of 0.99 atmospheres or more and 1.01 atmospheres or less, preferably 1.00 atmospheres; a temperature of 20 degrees or more and 30 degrees or less, preferably 25 degrees; and a humidity of 30% or less, preferably 0%.

[0061] Module 47 includes a calibration module 471 for performing a first calibration and a second calibration, an inspection module 472 for performing a first inspection and a second inspection, and any number of other modules 473 to supplement the functions provided by the control device 4.

[0062] The calibration module 471 has the function of controlling the gas sensor module 2 and the inspection device 3 and performing a first calibration and a second calibration. The processor 41 uses the calibration module 471 to send commands to the inspection circuit board 32 and the controller 36, respectively, to control the gas sensor module 2 and the inspection device 3. When performing the first calibration, the processor 41 uses the calibration module 471 to send a command to the controller 36 to perform the first calibration. Upon receiving the command, the controller 36 appropriately controls the opening and closing of predetermined valves to set the environment inside the chamber 31 to a clean air atmosphere. The calibration module 471 receives detection signals from the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D via the inspection circuit board 32, and after confirming that the environment inside the chamber 31 has been set to a clean air atmosphere, it sends a command to the inspection circuit board 32 to start measurement by the gas sensor module 2. Subsequently, the calibration module 471 receives a concentration signal from the gas sensor module 2 and calculates a correction coefficient 252 (offset coefficient) to correct the concentration value of the test gas to zero (zero point adjustment). Then, the calibration module 471 transmits the calculated correction coefficient 252 to the gas sensor module 2 via the test circuit board 32, and the gas sensor module 2 updates the correction coefficient 252 stored in the memory 24 based on the correction coefficient 252 received from the control device 4.

[0063] When performing the second calibration, the processor 41 uses the calibration module 471 to send a command to the controller 36 to perform the second calibration. Upon receiving the command, the controller 36 appropriately controls the opening and closing of predetermined valves to set the environment inside the chamber 31 to a standard concentration atmosphere. The calibration module 471 receives detection signals from the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D via the inspection circuit board 32, and after confirming that the environment inside the chamber 31 has been set to a standard concentration atmosphere, it sends a command to the inspection circuit board 32 to start measurement by the gas sensor module 2. Subsequently, the calibration module 471 receives a concentration signal from the gas sensor module 2 and calculates a correction coefficient 252, more specifically, coefficients a to d in the case of the above-mentioned quartic equation, to correct the concentration value of the test gas to an appropriate value. Subsequently, the calibration module 471 transmits the calculated correction coefficient 252 to the gas sensor module 2 via the test circuit board 32, and the gas sensor module 2 updates the correction coefficient 252 stored in the memory 24 based on the correction coefficient 252 received from the control device 4.

[0064] The inspection module 472 has the function of controlling the gas sensor module 2 and the inspection device 3 to perform the first and second inspections. The processor 41 uses the inspection module 472 to send commands to the inspection circuit board 32 and the controller 36, respectively, to control the gas sensor module 2 and the inspection device 3. When performing the first inspection, the processor 41 uses the inspection module 472 to send a command to the controller 36 to perform the first inspection. Upon receiving the command, the controller 36 appropriately controls the opening and closing of predetermined valves to set the environment inside the chamber 31 to a low-concentration inspection atmosphere. The inspection module 472 receives detection signals from the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D via the inspection circuit board 32, and after confirming that the environment inside the chamber 31 has been set to a low-concentration inspection atmosphere, it sends a command to the inspection circuit board 32 to start measurement by the gas sensor module 2. Subsequently, the inspection module 472 determines whether the gas sensor module 2 outputs a normal signal indicating that the concentration of the test gas in the chamber 31 is below the threshold of 253 and is normal. If the inspection module 472 confirms that the gas sensor module 2 has output a normal signal, it determines that the first inspection was successful and proceeds to the second inspection. On the other hand, if the inspection module 472 confirms that the gas sensor module 2 has not output a normal signal, i.e., has output an alarm signal, it determines that the first inspection has failed and reports the failure of the first inspection to the processor 41. Upon receiving the report of the failure of the first inspection, the processor 41 notifies the user of the inspection system 1 of the error using the I / O interface 42 or the display unit 44.

[0065] When performing the second test, the processor 41 uses the test module 472 to send a command to the controller 36 to perform the second test. Upon receiving the command, the controller 36 appropriately controls the opening and closing of predetermined valves to set the environment inside the chamber 31 to a high-concentration test atmosphere. The test module 472 receives detection signals from the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D via the test circuit board 32, and after confirming that the environment inside the chamber 31 has been set to a high-concentration test atmosphere, it sends a command to the test circuit board 32 to start measurement by the gas sensor module 2. Subsequently, the test module 472 determines whether the gas sensor module 2 outputs an alarm signal indicating that the concentration of the test gas inside the chamber 31 is above the threshold 253 and that an alarm should be issued. When the test module 472 confirms that the gas sensor module 2 has outputted an alarm signal, it determines that the second test was successful and reports the completion of both the first and second tests to the processor 41. Upon receiving reports of the success of the first and second inspections, the processor 41 notifies the user of the inspection system 1 of the completion of the inspection of the gas sensor module 2 using the I / O interface 42 or the display unit 44. Meanwhile, the inspection module 472, upon confirming that the gas sensor module 2 is not outputting an alarm signal, i.e., is outputting a normal signal, determines that the second inspection has failed and reports the failure of the second inspection to the processor 41. Upon receiving the report of the failure of the second inspection, the processor 41 notifies the user of the inspection system 1 of the error using the I / O interface 42 or the display unit 44. In the above description, the second inspection is performed after the first inspection, but the present invention is not limited thereto. An embodiment in which the first inspection is performed after the second inspection is also within the scope of the present invention.

[0066] <Gas Cylinders 5A-5D> Returning to Figure 1, gas cylinders 5A-5D are the gas supply sources used in inspections (first calibration, second calibration, first inspection, and second inspection) for the purpose of calibration, adjustment, and operational verification of the gas sensor module 2. Gas cylinders 5A-5C each store inspection gases of different concentrations. Gas cylinder 5D stores nitrogen gas. The inspection gases in gas cylinders 5A-5C are pre-adjusted to predetermined concentrations. Since the inspection system 1 uses pre-adjusted (diluted) inspection gases, there is no need to dilute 100% concentration inspection gas (ultra-high concentration gas) with nitrogen gas or the like to adjust it to a predetermined concentration during inspection. This improves the efficiency of calibration and inspection work for the gas sensor module 2, as well as enhances safety. In particular, the higher the concentration of R32 used as an inspection gas, the higher the possibility of ignition, but the inspection system 1 can significantly reduce safety risks by using pre-adjusted and appropriately diluted inspection gases.

[0067] Gas cylinder 5A stores the standard gas used in the second calibration. The standard gas stored in gas cylinder 5A is a test gas adjusted to have a concentration of 9500 ppm or more and 10500 ppm or less, preferably 10000 ppm. Gas cylinder 5A is connected to storage container 6A via a flow path equipped with valve 7A. When valve 7A is open, gas cylinder 5A and storage container 6A are in communication, and the standard gas in gas cylinder 5A is supplied to storage container 6A via the flow path equipped with valve 7A. Valve 7A is always kept closed, except during maintenance of the inspection system 1 and when supplying standard gas to storage container 6A.

[0068] Gas cylinder 5B stores the low-concentration gas used in the first inspection. The low-concentration gas stored in gas cylinder 5B is an inspection gas whose concentration is adjusted to be less than the threshold 253 stored in the memory 24 of the gas sensor module 2, more specifically between 5630 ppm and 6630 ppm, preferably 6130 ppm. Gas cylinder 5B is connected to storage container 6B via a flow path equipped with valve 7B. When valve 7B is open, gas cylinder 5B and storage container 6B are in communication, and the low-concentration gas in gas cylinder 5B is supplied to storage container 6B via the flow path equipped with valve 7B. Valve 7B is always kept closed, except during maintenance of the inspection system 1 and when supplying low-concentration gas to storage container 6B.

[0069] Gas cylinder 5C stores the high-concentration gas used in the second inspection. The high-concentration gas stored in gas cylinder 5C is an inspection gas whose concentration is adjusted to be above a threshold value 253 stored in the memory 24 of the gas sensor module 2, more specifically between 13370 ppm and 14370 ppm, preferably 13870 ppm. Gas cylinder 5C is connected to storage container 6C via a flow path equipped with valve 7C. When valve 7C is open, gas cylinder 5C and storage container 6C are in communication, and the high-concentration gas in gas cylinder 5C is supplied to storage container 6C via the flow path equipped with valve 7C. Valve 7C is always kept closed, except during maintenance of the inspection system 1 and when supplying high-concentration gas to storage container 6C.

[0070] Gas cylinder 5D stores nitrogen gas. Gas cylinder 5D is connected to valve 33D of air supply device 33 via a flow path. When valve 33D and air supply valve 37A are open, nitrogen gas in gas cylinder 5D is supplied into chamber 31 via air supply device 33. In this embodiment, nitrogen gas is mainly used as a purge gas. Specifically, it is used to create a clean air atmosphere that satisfies the first calibration conditions 461 during the first calibration. By filling chamber 31 with nitrogen gas, the existing air (and potential test gas) in chamber 31 is replaced. This process creates a clean air atmosphere that does not contain the test gas, which is the atmosphere for performing the first calibration.

[0071] Furthermore, nitrogen gas is used as a purge gas to remove unwanted gases and substances from the chamber 31 after the completion of the second inspection. Specifically, first, the exhaust device 34 is used to recover any harmful inspection gas (R32) remaining in the chamber 31 into one of the corresponding storage containers 6A to 6C. Next, the air supply device 33 is used to replace the atmosphere inside the chamber 31 with nitrogen gas. This nitrogen gas replacement process completely removes harmful gases from the chamber 31. This series of operations ensures the safety of the user when removing the gas sensor module 2 from the chamber 31. Moreover, because the chamber 31 is filled with nitrogen gas, it is difficult for outside air to flow into the chamber 31 when the chamber 31 is opened, preventing contamination from the external environment when removing the gas sensor module 2. As a result, it is possible to remove the gas sensor module 2 from the chamber 31 in a safe and clean state. In addition, it is possible to prevent outside air from flowing into the storage containers 6A to 6C. Furthermore, during regular maintenance of the inspection system 1, it is possible to clean the inside of storage containers 6A to 6C by exhausting the inspection gas from the containers and rinsing them with nitrogen gas.

[0072] <Storage Containers 6A-6C> Storage containers 6A-6C are components for storing the test gas supplied from gas cylinders 5A-5C, respectively. As shown in Figure 1, each of the storage containers 6A-6C is connected via a flow path to the corresponding gas cylinder 5A-5C, the air supply device 33, and the exhaust device 34. During the process of supplying the test gas to the chamber 31, the test gas is transferred from one of the storage containers 6A-6C towards the air supply device 33, and the test gas is supplied into the chamber 31 via the air supply device 33. During the process of discharging the test gas from the chamber 31, the test gas is transferred from the chamber 31 via the exhaust device 34, recovered in the corresponding storage container 6A-6C, and stored again. In this way, the used test gas is recovered and stored in the corresponding storage container 6A-6C after the inspection is completed, making it possible to reuse the test gas. As a result, it becomes unnecessary to dispose of the test gas each time, significantly reducing the amount of waste and the frequency of exhaust. This reduces the cost of pollution treatment required when exhausting the test gas, and also significantly reduces the total operating costs, including material costs and waste disposal costs related to the inspection.

[0073] Each of the storage containers 6A to 6C is a gas bag formed from a flexible material capable of storing test gases such as R32 with high airtightness. The flexible material forming each of the storage containers 6A to 6C is, for example, a resin material. Since each of the storage containers 6A to 6C is a flexible gas bag whose internal volume changes according to the volume of the stored test gas, the test gas can be recovered without compression. Specifically, the flexible material forming each of the storage containers 6A to 6C has high flexibility and possesses the characteristic of expanding or contracting in response to increases or decreases in the amount of test gas. As a result, when recovering the test gas, each of the storage containers 6A to 6C naturally changes its shape in accordance with the volume change of the test gas, making it possible to maintain a substantially constant internal pressure. Furthermore, this flexible characteristic suppresses a rapid increase in the gas pressure inside each of the storage containers 6A to 6C, making it possible to maintain a state substantially close to atmospheric pressure (preferably 0.99 atmospheres or more and 1.01 atmospheres or less, more preferably 1.00 atmospheres). As a result, the test gas can be efficiently recovered without forcibly compressing it, simplifying the recovery process and improving safety.

[0074] Furthermore, during the process of exhausting the inspection gas from the chamber 31 after the inspection is completed, the pressure difference between the pressure in a corresponding storage container 6A to 6C and the pressure in the chamber 31 is naturally reduced due to the soft properties of each storage container 6A to 6C. This makes it possible to transfer the inspection gas into a corresponding storage container 6A to 6C with less power, thereby improving energy efficiency. As a result, large-scale pump equipment becomes unnecessary, the overall configuration of the inspection device 3 can be simplified, and the inspection device 3 can be made smaller.

[0075] An example of a gas bag used as storage container 6A to 6C is a helium gas bag capable of storing helium gas without leakage. Since helium has the second smallest molecular weight after hydrogen, a gas bag capable of storing helium in an airtight manner has sufficient performance to store the test gas (R32), which has a larger molecular weight than helium, without leakage.

[0076] During maintenance of the inspection system 1, the inspection gas is discharged from one of the storage containers 6A to 6C to the chamber 31, and that storage container is emptied. Next, nitrogen gas is supplied into the storage container 6A to 6C to rinse it, purging any remaining inspection gas and effectively cleaning the inside. After cleaning is complete, under the control of the controller 36, the valves 7A to 7C connecting the corresponding gas cylinder 5A to 5C to the storage container 6A to 6C are switched from the closed state to the open state, and new inspection gas is supplied from the gas cylinder 5A to 5C to the corresponding storage container 6A to 6C, filling it.

[0077] The storage container 6A is connected to the gas cylinder 5A via a flow path equipped with a valve 7A. Furthermore, the storage container 6A is connected to the air inlet of the chamber 31 via valve 33A and air supply valve 37A of the air supply device 33. In the second calibration, in response to control from the control device 4, the controller 36 opens valve 33A and air supply valve 37A, and maintains the closed state of valves 33B to 33D of the air supply device 33, exhaust valve 37B, and valves 34A to 34E of the exhaust device 34. As a result, the flow path connecting the storage container 6A to the air inlet of the chamber 31 is opened, and the standard gas in the storage container 6A is supplied into the chamber 31. When the environment inside the chamber 31 is set to a standard concentration atmosphere, in response to control from the control device 4, the controller 36 switches the open valve 33A and air supply valve 37A to a closed state. This closes the passage connecting the storage container 6A to the air inlet of the chamber 31, ending the supply of standard gas.

[0078] When the second calibration is completed and the standard gas in chamber 31 is to be exhausted, the controller 36, in response to control from the control device 4, maintains the closed state of valves 33A to 33D and the supply valve 37A of the supply device 33, and opens valves 34A and 37B of the exhaust device 34. This opens the passage connecting the exhaust port of chamber 31 to the storage container 6A. As a result, the standard gas in chamber 31 is transferred to the storage container 6A via the exhaust device 34 by the suction force of the pump 341 of the exhaust device 34, where it is recovered and stored. Once the transfer of the standard gas from chamber 31 to the storage container 6A is complete, the controller 36 closes valves 34A and 37B. As a result, the passage connecting the exhaust port of chamber 31 to the storage container 6A is closed, and the recovery of the standard gas is completed.

[0079] The storage container 6B is connected to the gas cylinder 5B via a flow path equipped with a valve 7B. Furthermore, the storage container 6B is connected to the air inlet of the chamber 31 via valve 33B and air supply valve 37A of the air supply device 33. In the first inspection, in response to control from the control device 4, the controller 36 maintains the closed state of valves 33A, 33C, and 33D of the air supply device 33, valves 34A to 34E and exhaust valve 37B of the exhaust device 34, and opens valve 33B and air supply valve 37A. As a result, the flow path connecting the storage container 6B to the air inlet of the chamber 31 is opened, and the low-concentration gas in the storage container 6B is supplied into the chamber 31. When the environment inside the chamber 31 is set to a low-concentration inspection atmosphere, in response to control from the control device 4, the controller 36 switches the open valve 33B and air supply valve 37A to a closed state. This closes the passage connecting the storage container 6B to the air inlet of the chamber 31, ending the supply of low-concentration gas.

[0080] When the first inspection is completed and it is time to exhaust the low-concentration gas from the chamber 31, the controller 36, in response to control from the control device 4, maintains the closed state of valves 33A to 33D and the supply valve 37A of the air supply device 33, and opens valves 34B and 37B of the exhaust device 34. This opens the passage connecting the exhaust port of the chamber 31 to the storage container 6B. As a result, the suction force of the pump 341 of the exhaust device 34 transfers the low-concentration gas from the chamber 31 to the storage container 6B via the exhaust device 34, where it is recovered and stored. Once the transfer of the low-concentration gas from the chamber 31 to the storage container 6B is complete, the controller 36 closes valves 34B and 37B. As a result, the passage connecting the exhaust port of the chamber 31 to the storage container 6B is closed, and the recovery of the low-concentration gas is completed.

[0081] The storage container 6C is connected to the gas cylinder 5C via a flow path equipped with a valve 7C. Furthermore, the storage container 6C is connected to the air inlet of the chamber 31 via the valve 33C and air supply valve 37A of the air supply device 33. In the second inspection, in response to control from the control device 4, the controller 36 opens valve 33C and the air supply valve 37A, while maintaining the closed state of valves 33A, 33B, 33D, valves 34A to 34E, and the exhaust valve 37B. As a result, the flow path connecting the storage container 6C to the air inlet of the chamber 31 is opened, and the high-concentration gas in the storage container 6C is supplied into the chamber 31. When the environment inside the chamber 31 is set to a high-concentration inspection atmosphere, in response to control from the control device 4, the controller 36 switches the open valve 33C and the air supply valve 37A to a closed state. This closes the passage connecting the storage container 6C to the air inlet of the chamber 31, ending the supply of high-concentration gas.

[0082] When the second inspection is completed and it is time to exhaust the high-concentration gas from chamber 31, the controller 36, in response to control from the control device 4, maintains the closed state of valves 33A to 33D and the supply valve 37A of the air supply device 33, and opens valves 34C and 37B of the exhaust device 34. This opens the passage connecting the exhaust port of chamber 31 to the storage container 6C. As a result, the suction force of the pump 341 of the exhaust device 34 transfers the high-concentration gas from chamber 31 to the storage container 6C via the exhaust device 34, where it is recovered and stored. Once the transfer of the high-concentration gas from chamber 31 to the storage container 6C is complete, the controller 36 closes valves 34C and 37B. As a result, the passage connecting the exhaust port of chamber 31 to the storage container 6C is closed, and the recovery of the high-concentration gas is completed.

[0083] <Valves 7A-7C> Valves 7A-7C are electromagnetically operated solenoid valves. Valves 7A-7C are electrically connected to the controller 36, and their open / closed state is controlled by the controller 36. Valves 7A-7C are installed in the flow path between the gas cylinders 5A-5C and the storage containers 6A-6C. Valve 7A also functions as a check valve that allows the one-way flow of standard gas from gas cylinder 5A to storage container 6A. Valve 7B also functions as a check valve that allows the one-way flow of low-concentration gas from gas cylinder 5B to storage container 6B. Valve 7C also functions as a check valve that allows the one-way flow of high-concentration gas from gas cylinder 5C to storage container 6C.

[0084] <Harmful Gas Detoxification Device 8> The harmless gas detoxification device 8 is a device that detoxifies the discharged test gas when it is discharged to the outside. The harmless gas detoxification device 8 is connected to the valve 34D of the exhaust device 34 via a flow path between the harmless gas detoxification device 8 and the exhaust device 34. For example, during maintenance of the inspection system 1, the test gas stored in the storage containers 6A to 6C is transferred to the chamber 31. Then, in response to control from the control device 4, the controller 36 switches the exhaust valve 37B and valve 34D to the open state, and the test gas in the chamber 31 is transferred to the harmless gas detoxification device 8 by the suction force of the pump 341. After that, the test gas is appropriately detoxified and rendered harmless, and is released into the atmosphere from the exhaust port of the harmless gas detoxification device 8 (not shown).

[0085] As mentioned above, since the test gas is recovered into storage containers 6A to 6C after the test is completed, the amount of test gas discharged to the outside (consumption) is significantly reduced. Therefore, the pollution control device 8 does not need to be a large-scale device and can be miniaturized and simplified. This reduces the cost required for disposing of the test gas. In addition, since the recovered test gas is reused, the frequency of external discharge of the test gas is also greatly reduced. This makes it possible to outsource the pollution control treatment to an external company, eliminating the need to introduce a large-scale pollution control treatment device. As a result, it is possible to significantly reduce the cost required for testing the gas sensor module 2.

[0086] <Inspection Method S100> The inspection method for the gas sensor module of the present invention is performed using the gas sensor module inspection system 1 described above. The inspection method for the gas sensor module of the present invention will be described in detail below with reference to Figures 4 and 5. Figure 4 is a flowchart of the inspection method for the gas sensor module of the present invention. Figure 5 is a flowchart showing the inspection method for the gas sensor module shown in Figure 4 in more detail.

[0087] The inspection method S100 of the present invention (hereinafter also referred to as "inspection method S100") is performed at any time by the administrator or user of the inspection system 1. Specifically, it is performed during the production process of the gas sensor module 2, but may also be performed during maintenance of the gas sensor module 2. First, in step S110, the user of the inspection system 1 opens the chamber 31 and places the gas sensor module 2 to be inspected inside the chamber 31. Specifically, the user mounts the gas sensor module 2 onto the inspection circuit board 32 inside the chamber 31, and then closes the chamber 31 to create a sealed space inside the chamber 31. Once the installation of the gas sensor module 2 inside the chamber 31 is complete, the process proceeds to step S120. In inspection method S100, the pump 341 of the exhaust device 34 is kept running at all times, at least between steps S120 and S170.

[0088] In step S120, the calibration module 471 performs a first calibration on the gas sensor module 2 in a clean air atmosphere. First, the calibration module 471 sends a command to the controller 36 to set the environment inside the chamber 31 to a clean air atmosphere that satisfies the first calibration condition 461. Upon receiving the command, the controller 36 appropriately controls the opening and closing of predetermined valves to set the environment inside the chamber 31 to a clean air atmosphere.

[0089] Specifically, the controller 36 closes valves 33A to 33D and the air supply valve 37A, and opens both valve 34E and the exhaust valve 37B. This opens the flow path between the exhaust port of the exhaust device 34 for atmospheric discharge and the chamber 31, and the gas in the chamber 31 is exhausted to the outside by the suction force of the pump 341. When the gas in the chamber 31 is exhausted to the outside, the pressure inside the chamber 31 decreases, and the environment inside the chamber 31 becomes a reduced pressure state, preferably a vacuum state. In the reduced pressure state where the pressure inside the chamber 31 has decreased, or when the environment inside the chamber 31 is a vacuum state, the controller 36 closes valve 34E and the exhaust valve 37B, and opens both valve 33D and the air supply valve 37A (valves 33A to 33C are kept closed). As a result, nitrogen gas from the gas cylinder 5D is supplied into the chamber 31 due to the pressure difference between the pressure inside the chamber 31 and the pressure inside the gas cylinder 5D.

[0090] While nitrogen gas is being supplied into the chamber 31, the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D in the chamber 31 each measure various parameters within the chamber 31 and transmit detection signals to the control device 4 via the inspection circuit board 32. Upon receiving these detection signals, the calibration module 471 determines whether the environment inside the chamber 31 is set to a clean air atmosphere. If the calibration module 471 determines that the environment inside the chamber 31 is not set to a clean air atmosphere, it performs exhaust from or supply to the chamber 31 again via the controller 36 to set the environment inside the chamber 31 to a clean air atmosphere. If the calibration module 471 determines that the environment inside the chamber 31 is set to a clean air atmosphere, it sends a command to the controller 36 to close the open valve 33D and the supply valve 37A. As a result, the environment inside the chamber 31 is maintained to a clean air atmosphere.

[0091] With the environment of the chamber 31 maintained in a clean air atmosphere, the calibration module 471 sends a command to the inspection circuit board 32 to start measurement by the gas sensor module 2. Once the measurement is complete, the gas sensor module 2 transmits a concentration signal to the control device 4 via the inspection circuit board 32. Subsequently, the calibration module 471 calculates a correction coefficient 252 (constant term e) to correct the concentration value of the test gas to zero (zero point adjustment) based on the concentration signal received from the gas sensor module 2. Then, the calibration module 471 transmits the calculated correction coefficient 252 to the gas sensor module 2 via the inspection circuit board 32, and the gas sensor module 2 updates the correction coefficient 252 (constant term e) stored in the memory 24 based on the correction coefficient 252 received from the control device 4. Once the update of the correction coefficient 252 (constant term e) to the gas sensor module 2 is complete, process S120 ends, and the process proceeds to process S130.

[0092] In step S130, the calibration module 471 begins preparations to start the second calibration. First, the calibration module 471 sends a command to the controller 36 to exhaust the gas in the chamber 31 to the outside. Upon receiving the command, the controller 36 opens both valve 34E and exhaust valve 37B. This opens the flow path between the exhaust port of the exhaust device 34 and the chamber 31, and the gas in the chamber 31 is exhausted to the outside by the suction force of the pump 341. Once the chamber 31 is exhausted, the pressure inside the chamber 31 decreases, and the environment inside the chamber 31 becomes a reduced pressure state, preferably a vacuum state. With the environment inside the chamber 31 in a reduced pressure state or a vacuum state, the controller 36 closes valve 34E and exhaust valve 37B. Subsequently, the controller 36 maintains the closed state of valves 33B to 33D, valves 34A to 34E, and the exhaust valve 37B, while opening both valve 33A and the supply valve 37A. As described above, since the chamber 31 is under reduced pressure or a vacuum, a pressure difference is created between the pressure in the storage container 6A and the pressure in the chamber 31, and the standard gas in the storage container 6A moves into the chamber 31, where the pressure is lower than inside the storage container 6A (it is supplied). In this way, by utilizing the pressure difference between the pressure in the storage container 6A and the pressure in the chamber 31, the standard gas in the storage container 6A can be supplied into the chamber 31, eliminating the need to provide additional power such as a pump for supplying air to the supply device 33. As a result, the inspection device 3 can be simplified, and the introduction and maintenance costs of the inspection system 1 can be reduced.

[0093] While standard gas is being supplied into the chamber 31, the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D each measure various parameters within the chamber 31 and transmit detection signals to the control device 4 via the inspection circuit board 32. Upon receiving these detection signals, the calibration module 471 determines whether the environment within the chamber 31 is set to a standard concentration atmosphere. If the calibration module 471 determines that the environment within the chamber 31 is not set to a standard concentration atmosphere, it restarts exhaust from or supplying air to the chamber 31 via the controller 36 to set the environment within the chamber 31 to a standard concentration atmosphere. If the calibration module 471 determines that the environment within the chamber 31 is set to a standard concentration atmosphere, it sends a command to the controller 36 to switch the open valve 33A and the air supply valve 37A to a closed state. As a result, the environment in the chamber 31 is maintained at a standard concentration atmosphere. Once the environment in chamber 31 is set to a standard concentration atmosphere, step S130 is completed, and the process proceeds to step S140.

[0094] In step S140, the calibration module 471 performs a second calibration on the gas sensor module 2 under a standard concentration atmosphere. First, the calibration module 471 sends a command to the inspection circuit board 32 to start measurement by the gas sensor module 2. Once measurement is complete, the gas sensor module 2 transmits a concentration signal to the control device 4 via the inspection circuit board 32. Subsequently, the calibration module 471 calculates a correction coefficient 252, more specifically, coefficients a to d in the case of the above-mentioned fourth-order equation, to correct the concentration value of the test gas to an appropriate value based on the concentration signal received from the gas sensor module 2. Then, the calibration module 471 transmits the calculated correction coefficient 252 to the gas sensor module 2 via the inspection circuit board 32, and the gas sensor module 2 updates the correction coefficient 252 stored in the memory 24 based on the correction coefficient 252 received from the calibration module 471. Once the update of the correction coefficient 252 to the gas sensor module 2 is complete, step S140 ends, and the process proceeds to step S150.

[0095] In step S150, the calibration module 471 sends a command to the controller 36 to evacuate the chamber 31 and recover the standard gas in the chamber 31 into the storage container 6A. Upon receiving the command, the controller 36 maintains the closed state of valves 33A to 33D, the air supply valve 37A, and valves 34B to 34E, while opening both valve 34A and the exhaust valve 37B. This opens the passage connecting the exhaust port of the chamber 31 to the storage container 6A. As a result, the suction force of the pump 341 returns the standard gas in the chamber 31 to the storage container 6A via the exhaust device 34, where it is recovered and stored. Once the recovery of the standard gas in the chamber 31 is complete, the controller 36 closes valve 34A and the exhaust valve 37B, ending the exhaust of the standard gas from the chamber 31. Due to the exhaust of the standard gas from the chamber 31, the chamber 31 becomes a reduced-pressure state, preferably a vacuum state. When valve 34A and exhaust valve 37B are closed, process S150 ends and the process proceeds to process S160.

[0096] In step S160, the inspection module 472 of the control device 4 controls the gas sensor module 2 and the inspection device 3 to perform a first inspection and a second inspection on the gas sensor module 2. As shown in Figure 5, first, in step S161, the inspection module 472 sends a command to the controller 36 to supply low-concentration gas into the chamber 31 and set the environment inside the chamber 31 to a low-concentration inspection atmosphere. Upon receiving the command, the controller 36 maintains the closed state of valves 33A, 33C, 33D, valves 34A to 34E and the exhaust valve 37B, and opens valve 33B and the supply valve 37A. As a result, the flow path connecting the storage container 6B to the air inlet of the chamber 31 is opened. As described above, since the chamber 31 is under reduced pressure or a vacuum, a pressure difference is created between the pressure inside the storage container 6B and the pressure inside the chamber 31. The low-concentration gas inside the storage container 6B moves into the chamber 31, where the pressure is lower than inside the storage container 6B (it is supplied). In this way, the low-concentration gas inside the storage container 6B can be supplied into the chamber 31 by utilizing the pressure difference between the pressure inside the storage container 6B and the pressure inside the chamber 31.

[0097] While low-concentration gas is being supplied into the chamber 31, the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D each measure various parameters within the chamber 31 and transmit detection signals to the control device 4 via the inspection circuit board 32. Upon receiving the detection signals, the inspection module 472 determines whether the environment inside the chamber 31 is set to a low-concentration inspection atmosphere. If the inspection module 472 determines that the environment inside the chamber 31 is not set to a low-concentration inspection atmosphere, it performs exhaust from or supply to the chamber 31 again via the controller 36 to set the environment inside the chamber 31 to a low-concentration inspection atmosphere. If the inspection module 472 determines that the environment inside the chamber 31 is set to a low-concentration inspection atmosphere, it sends a command to the controller 36 to close valve 33B and the supply valve 37A. Upon receiving the command, the controller 36 closes valve 33B and the supply valve 37A and terminates the supply of low-concentration gas into the chamber 31. Once the environment inside chamber 31 is set to a low-concentration testing atmosphere, step S161 ends and the process proceeds to step S162.

[0098] In step S162, the inspection module 472 of the control device 4 performs a first inspection on the gas sensor module 2 under a low-concentration inspection atmosphere. First, the inspection module 472 sends a command to the inspection circuit board 32 to start measurement by the gas sensor module 2. When the measurement is complete, the gas sensor module 2 sends a concentration signal and either an alarm signal or a normal signal to the control device 4 via the inspection circuit board 32. When the inspection module 472 confirms that the gas sensor module 2 has output a normal signal, it determines that the first inspection was successful. Once it is determined that the first inspection was successful, step S162 ends and the process proceeds to step S163. On the other hand, when the inspection module 472 confirms that the gas sensor module 2 has not output a normal signal, i.e., has output an alarm signal, it determines that the first inspection has failed and reports the failure of the first inspection to the processor 41. Upon receiving the report of the failure of the first inspection, the processor 41 notifies the user of the inspection system 1 of the error using the I / O interface 42 or the display unit 44. If an error is reported, process S162 ends, and the process proceeds to process S163.

[0099] In step S163, the inspection module 472 sends a command to the controller 36 to evacuate the chamber 31 and recover the low-concentration gas in the chamber 31 into the storage container 6B. Upon receiving the command, the controller 36 maintains the closed state of valves 33A to 33D and the supply valve 37A of the air supply device 33, and opens valves 34B and the exhaust valve 37B of the exhaust device 34. This opens the passage connecting the exhaust port of the chamber 31 to the storage container 6B. As a result, the suction force of the pump 341 transfers the low-concentration gas in the chamber 31 to the storage container 6B via the exhaust device 34, where it is recovered and stored. Once the recovery of the low-concentration gas in the chamber 31 is complete, the controller 36 closes valves 34B and the exhaust valve 37B, ending the exhaust from the chamber 31. Due to the exhaust of the low-concentration gas from the chamber 31, the chamber 31 becomes a reduced-pressure state, preferably a vacuum state. When valve 34B and exhaust valve 37B are closed, process S163 ends. If the first inspection in process S162 is successful, the process proceeds to process S164. On the other hand, if the first inspection in process S162 fails, process S160 is interrupted and the process proceeds to processes S170 and S180, which will be described later.

[0100] In step S164, the inspection module 472 sends a command to the controller 36 to supply high-concentration gas into the chamber 31 and set the environment inside the chamber 31 to a high-concentration inspection atmosphere. Upon receiving the command, the controller 36 maintains the closed state of valves 33A, 33B, 33D, valves 34A to 34E and exhaust valve 37B, and opens valve 33C and supply valve 37A. As a result, the flow path connecting the storage container 6C to the air supply port of the chamber 31 is opened. As described above, since the inside of the chamber 31 is under reduced pressure or a vacuum, a pressure difference is created between the pressure inside the storage container 6C and the pressure inside the chamber 31, and the high-concentration gas inside the storage container 6C moves into the chamber 31, where the pressure is lower than inside the storage container 6C (it is supplied). In this way, the high-concentration gas inside the storage container 6C can be supplied into the chamber 31 by utilizing the pressure difference between the pressure inside the storage container 6C and the pressure inside the chamber 31.

[0101] While high-concentration gas is being supplied into the chamber 31, the gas sensor 35A, pressure sensor 35B, humidity sensor 35C, and temperature sensor 35D each measure various parameters within the chamber 31 and transmit detection signals to the control device 4 via the inspection circuit board 32. Upon receiving the detection signals, the inspection module 472 determines whether the environment inside the chamber 31 is set to a high-concentration inspection atmosphere. If the inspection module 472 determines that the environment inside the chamber 31 is not set to a high-concentration inspection atmosphere, it performs exhaust from or supply to the chamber 31 again via the controller 36 to set the environment inside the chamber 31 to a high-concentration inspection atmosphere. If the inspection module 472 determines that the environment inside the chamber 31 is set to a high-concentration inspection atmosphere, it sends a command to the controller 36 to close valve 33C and the supply valve 37A. Upon receiving the command, the controller 36 closes valve 33C and the supply valve 37A and terminates the supply of high-concentration gas into the chamber 31. Once the environment inside chamber 31 is set to a high-concentration testing atmosphere, step S164 ends and the process proceeds to step S165.

[0102] In step S165, the inspection module 472 of the control device 4 performs a second inspection on the gas sensor module 2 under a high-concentration inspection atmosphere. First, the inspection module 472 sends a command to the inspection circuit board 32 to start measurement by the gas sensor module 2. When the measurement is complete, the gas sensor module 2 sends a concentration signal and either an alarm signal or a normal signal to the control device 4 via the inspection circuit board 32. When the inspection module 472 confirms that the gas sensor module 2 has output an alarm signal, it determines that the second inspection was successful. Once it is determined that the second inspection was successful, step S165 ends and the process proceeds to step S166. On the other hand, when the inspection module 472 confirms that the gas sensor module 2 has not output an alarm signal, i.e., has output a normal signal, it determines that the second inspection has failed and reports the failure of the second inspection to the processor 41. Upon receiving the report of the failure of the second inspection, the processor 41 notifies the user of the inspection system 1 of the error using the I / O interface 42 or the display unit 44. If an error is reported, process S165 ends, and the process proceeds to process S166.

[0103] In step S166, the inspection module 472 sends a command to the controller 36 to evacuate the chamber 31 and recover the high-concentration gas in the chamber 31 into the storage container 6C. Upon receiving the command, the controller 36 controls the valves 33A to 33D and the supply valve 37A of the air supply device 33 to remain closed, and the valves 34C and the exhaust valve 37B of the exhaust device 34 to be opened. This opens the passage connecting the exhaust port of the chamber 31 to the storage container 6C. As a result, the suction force of the pump 341 transfers the high-concentration gas in the chamber 31 to the storage container 6C via the exhaust device 34, where it is recovered and stored. Once the recovery of the high-concentration gas in the chamber 31 is complete, the controller 36 closes the valves 34C and the exhaust valve 37B, ending the evacuation from the chamber 31. The evacuation of the high-concentration gas from the chamber 31 creates a reduced pressure state, preferably a vacuum state, inside the chamber 31. When valve 34C and exhaust valve 37B are closed, process S166 ends and the process proceeds to process S170.

[0104] Returning to Figure 4, in step S170, the inspection module 472 sends a command to the controller 36 to supply nitrogen gas into the chamber 31 and purge the internal space of the chamber 31. In the steps prior to step S170, the inspection gas has been recovered into storage containers 6A to 6C, but there is a possibility that a small amount of inspection gas remains in the chamber 31. Therefore, the internal space of the chamber 31 is purged with nitrogen gas to prevent harmful inspection gas from being released to the outside when the chamber 31 is opened. First, the controller 36, upon receiving the command, maintains the closed state of valves 33A to 33C and valves 34A to 34C and 34E, and opens valve 33D, the air supply valve 37A, valve 34D, and the exhaust valve 37B. As described above, since the chamber 31 is under reduced pressure or a vacuum, a pressure difference exists between the pressure in the gas cylinder 5D and the pressure in the chamber 31. The nitrogen gas in the gas cylinder 5D is supplied (feeded) into the chamber 31, where the pressure is lower than that inside the gas cylinder 5D. The test gas remaining in the chamber 31 is pushed out by the supplied nitrogen gas and transferred from the exhaust port of the chamber 31 to the abatement device 8 via the exhaust device 34. As a result, the test gas in the chamber 31 is replaced with nitrogen gas, and the internal space of the chamber 31 is purged. This removes harmful test gases from the chamber 31, ensuring the safety of the user when removing the gas sensor module 2 from the chamber 31 and reducing the environmental burden. Once the residual test gas in the chamber 31 has been exhausted and the chamber 31 is filled with nitrogen gas, the controller 36 closes valve 33D, the supply valve 37A, valve 34D, and the exhaust valve 37B. This completes process S170, and the process proceeds to S180.

[0105] In step S180, the user removes the gas sensor module 2 from inside the chamber 31, completing step S180. Once step S180 is completed, inspection method S100 is also completed.

[0106] As described above, the gas sensor module inspection system 1 and gas sensor module inspection method S100 of the present invention allow the inspection gas to be recovered and stored in gas storage containers 6A to 6C without being discharged to the outside each time an inspection is performed, and reused. As a result, the amount of inspection gas consumed can be significantly reduced, and as a result, it is possible to eliminate the need to replenish the gas storage containers 6A to 6C with new inspection gas, or to significantly reduce the frequency of replenishing the inspection gas. This reduces the cost of continuous procurement of inspection gas and lowers the overall cost of inspecting the gas sensor module 2.

[0107] Furthermore, the gas sensor module inspection system 1 and gas sensor module inspection method S100 of the present invention allow the inspection gas to be recovered and stored in gas storage containers 6A to 6C after the inspection of the gas sensor module 2 for reuse, thereby significantly reducing the frequency of external discharge of the inspection gas. As a result, the number of times pollution treatment is performed on the inspection gas for disposal can be significantly reduced, and the overall cost of inspecting the gas sensor module 2 can be significantly reduced. Moreover, by significantly reducing the frequency of external discharge of the inspection gas, it becomes easier to outsource pollution treatment to an external company, eliminating the need to introduce large-scale pollution treatment equipment that was conventionally required for inspecting the gas sensor module 2. As a result, the cost required for inspecting the gas sensor module 2 can be significantly reduced.

[0108] Furthermore, in the gas sensor module inspection system 1 and gas sensor module inspection method S100 of the present invention, the inspection gas can be supplied from one of the storage containers 6A to 6C to the chamber 31 by utilizing the differential pressure between the pressure in one of the storage containers 6A to 6C and the pressure in the chamber 31. Therefore, it is unnecessary to provide additional power such as an air supply pump to the air supply device 33. As a result, the inspection device 3 can be simplified, and the introduction cost and maintenance cost of the inspection system 1 can be reduced.

[0109] Although the inspection system and inspection method for the gas sensor module of the present invention have been described above based on the illustrated embodiments, the present invention is not limited thereto. The configuration of each component of the present invention can be replaced with any other component that can perform a similar function, or any other component can be added to the configuration of the present invention.

[0110] Those skilled in the art and the field to which the present invention belongs will be able to modify the configuration of the inspection system and inspection method of the present invention described without significantly departing from the principles, concepts, and scope of the present invention, and the inspection system and inspection method having the modified configuration will also be within the scope of the present invention.

[0111] According to the gas sensor module inspection system and gas sensor module inspection method of the present invention, the inspection gas can be recovered and reused without being discharged to the outside each time an inspection is performed. As a result, the consumption of inspection gas can be significantly reduced, eliminating the need to replenish the gas storage container with new inspection gas, or significantly reducing the frequency of gas replenishment. This reduces the cost of continuous procurement of inspection gas and lowers the overall cost of inspecting gas sensor modules. Furthermore, according to the gas sensor module inspection system and gas sensor module inspection method of the present invention, since the inspection gas can be recovered and reused after performing an inspection on the gas sensor module, the frequency of discharge of inspection gas to the outside can be significantly reduced. As a result, the number of times pollution treatment is applied to the inspection gas for disposal can be significantly reduced, and the overall cost of inspecting gas sensor modules can be significantly reduced. Moreover, by significantly reducing the frequency of discharge of inspection gas to the outside, it becomes easier to outsource pollution treatment to an external company, eliminating the need to introduce large-scale pollution treatment equipment that was conventionally required for inspecting gas sensor modules. As a result, the cost required for inspecting gas sensor modules can be significantly reduced. Therefore, the present invention has industrial applicability.

Claims

1. A gas sensor module inspection system comprising: a storage container for storing an inspection gas; a chamber in which a gas sensor module is housed and the inspection gas is supplied to the chamber from the storage container; an air supply device provided between the storage container and the chamber for supplying the inspection gas from the storage container into the chamber; an exhaust device provided between the storage container and the chamber for returning the inspection gas in the chamber back into the storage container; and a control device for controlling the air supply device and the exhaust device, wherein the control device controls the air supply device and sets the environment inside the chamber to predetermined conditions to perform an inspection on the gas sensor module; and after the inspection on the gas sensor module is completed, the control device controls the exhaust device and returns the inspection gas in the chamber back into the storage container.

2. The inspection system for a gas sensor module according to claim 1, wherein the exhaust device includes an exhaust pump for reducing the pressure of the environment inside the chamber.

3. The inspection system for a gas sensor module according to claim 1, wherein the storage container is a gas bag formed of a soft material.

4. The inspection system for a gas sensor module according to claim 3, wherein the gas bag is configured such that its internal volume changes according to the volume of the inspection gas stored inside the gas bag, thereby maintaining the pressure inside the gas bag at all times between 0.99 atmospheres and 1.01 atmospheres.

5. The gas sensor module inspection system according to claim 1, wherein the predetermined conditions include: a first inspection condition in which the concentration of the test gas in the chamber is 5630 ppm or more and 6630 ppm or less; and a second inspection condition in which the concentration of the test gas in the chamber is 13370 ppm or more and 14370 ppm or less, and the inspection of the gas sensor module includes: a first inspection to determine whether the gas sensor module outputs a normal signal indicating that the concentration of the test gas is below a predetermined threshold under the first inspection condition; and a second inspection to determine whether the gas sensor module outputs an alarm signal indicating that the concentration of the test gas is above a predetermined threshold under the second inspection condition.

6. The control device is further configured to perform calibration of the gas sensor module by controlling the air supply device, wherein the predetermined conditions include: a first calibration condition in which the concentration of the test gas in the chamber is 500 ppm or less; and a second calibration condition in which the concentration of the test gas in the chamber is 9500 ppm or more and 10500 ppm or less; the calibration of the gas sensor module includes: a first calibration under the first calibration condition, which involves receiving a concentration signal output from the gas sensor module and calculating a correction coefficient to correct the concentration value of the test gas to an appropriate value; and a second calibration under the second calibration condition, which involves receiving the concentration signal output from the gas sensor module and calculating a correction coefficient to adjust the sensitivity of the gas sensor module, wherein the calibration of the gas sensor module is performed before the inspection of the gas sensor module, as described in claim 1.

7. The inspection system for a gas sensor module according to claim 1, wherein the storage container is a gas bag formed of a soft material.

8. The inspection system for a gas sensor module according to claim 7, wherein the gas bag is configured such that its internal volume changes according to the volume of the inspection gas stored inside the gas bag, thereby maintaining the pressure inside the gas bag at all times between 0.99 atmospheres and 1.01 atmospheres.

9. The gas sensor module inspection system according to claim 1, wherein the air supply device comprises a valve for opening and closing a flow path between the storage container and the chamber, the exhaust device comprises a pump for exhausting gas from the chamber and a valve for opening and closing a flow path between the pump and the storage container, the control device reduces the pressure in the chamber by the pump by closing the valve of the air supply device and opening the valve of the exhaust device, the control device, in a state where the pressure in the chamber has been reduced, closes the valve of the exhaust device and further opens the valve of the air supply device to supply the inspection gas into the chamber using the differential pressure between the pressure in the chamber and the pressure in the storage container, and the inspection of the gas sensor module is performed in a state where the inspection gas is supplied into the chamber.

10. The inspection system for a gas sensor module according to claim 9, wherein the pump of the exhaust device is an exhaust pump for reducing the pressure in the chamber by exhausting the gas in the chamber, and the control device reduces the pressure in the chamber by the exhaust pump by closing the valve of the air supply device and further opening the valve of the exhaust device.

11. A method for inspecting a gas sensor module, comprising the steps of: using an air supply device to supply an inspection gas from a storage container into a chamber in which a gas sensor module is housed, and setting the environment inside the chamber to predetermined conditions; using a control device to perform an inspection on the gas sensor module; and using an exhaust device to return the inspection gas in the chamber to the storage container.

12. The method for inspecting a gas sensor module according to claim 11, further comprising the step of supplying nitrogen gas into the chamber using the air supply device after the step of returning the inspection gas in the chamber to the storage container.

13. The method for inspecting a gas sensor module according to claim 11, comprising the steps of: reducing the pressure in the chamber by pumping by closing the valve of the air supply device provided between the storage container and the chamber and opening the valve of the exhaust device provided between the storage container and the pump of the exhaust device; and, in a state where the pressure in the chamber has been reduced, supplying the inspection gas into the chamber by utilizing the differential pressure between the pressure in the chamber and the pressure in the storage container by closing the valve of the exhaust device and further opening the valve of the air supply device.

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