Gas detection device and gas detection system

Abstract

This system provides accurate detection of the concentration of components in odorous gases emitted from the feces of a subject. [Solution] The gas detection device 1 comprises a sampling unit 21, a first gas sensor 24a, and a second gas sensor 24b. The sampling unit collects a sample gas containing a first gas to be detected and a second gas to be detected. The first gas sensor and the second gas sensor are sensors capable of detecting both the first gas to be detected and the second gas to be detected. The first gas sensor and the second gas sensor have different relative detection sensitivities for the first gas to be detected and for the second gas to be detected.

Description

Technical Field

[0001] The present disclosure relates to a gas detection device for detecting the concentration of a gas and a gas detection system including the gas detection device.

Background Art

[0002] A system for detecting an odor gas generated from feces discharged by a subject is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] A gas detection device according to an aspect of the present disclosure includes a sample gas collection unit that collects a sample gas including a first detected gas and a second detected gas in a storage tank, a gas detection unit including a plurality of gas sensors including a first gas sensor and a second gas sensor capable of detecting both the first detected gas and the second detected gas included in the sample gas, a sensor chamber that stores the gas detection unit therein, a chamber pump that performs introduction of the sample gas from the storage tank to the sensor chamber and exhaust of the sample gas from the sensor chamber to the outside, and a control unit that controls the chamber pump, and the control unit controls the chamber pump so as to repeat the introduction and the exhaust.

[0005] Furthermore, a gas detection system according to one aspect of the present disclosure includes: a sample gas sampling unit that collects a sample gas containing a first gas to be detected and a second gas to be detected into a storage tank; a gas detection unit equipped with a plurality of gas sensors, including a first gas sensor and a second gas sensor, capable of detecting both the first gas to be detected and the second gas to be detected contained in the sample gas; a sensor chamber that houses the gas detection unit inside; a chamber pump that introduces the sample gas from the storage tank into the sensor chamber and exhausts the sample gas from the sensor chamber to the outside; a control unit that controls the chamber pump; and an estimation unit that estimates the concentrations of the first gas to be detected and the second gas to be detected based on a first detection signal output from the first gas sensor and a second detection signal output from the second gas sensor, wherein the control unit controls the chamber pump to repeat the introduction and exhaust. [Brief explanation of the drawing]

[0006] [Figure 1] This is an external view showing an example of the configuration of an analysis system according to one embodiment of this disclosure. [Figure 2] This is a schematic diagram showing an example of the configuration of a gas detection device according to one embodiment of the present disclosure. [Figure 3] This is a block diagram showing an example of the configuration of a gas detection device according to one embodiment of the present disclosure. [Figure 4] This graph shows an example of the variation in the first detection signal caused by hydrogen sulfide and methyl mercaptan. [Figure 5] This graph shows an example of fluctuations in the second detection signal caused by hydrogen sulfide and methyl mercaptan. [Figure 6] This is a partial cross-sectional view showing an example of the configuration of the first gas sensor included in the gas sensor group. [Figure 7] This is a schematic diagram showing an example of the configuration of a gas detection device according to Embodiment 3. [Figure 8] This is a schematic diagram showing an example of the configuration of a gas detection device according to Embodiment 5. [Modes for carrying out the invention]

[0007] [Embodiment 1] One embodiment of this disclosure will be described in detail below.

[0008] <Analysis System 100> Figure 1 is an external view showing an example of the configuration of an analysis system 100 according to one embodiment of this disclosure. Each figure referenced herein is a schematic diagram that simplifies only some of the components in order to illustrate the embodiment for the sake of convenience of explanation. Therefore, the analysis system 100 may include any components not shown in the figures referenced herein. Furthermore, the dimensions of the components in each figure do not faithfully represent the dimensions of the actual components or the dimensional ratios of each component.

[0009] The analysis system 100 shown in Figure 1 may be called a "gas detection system" or a "gas analysis system." As shown in Figure 1, the analysis system 100 comprises a gas detection device 1 and an electronic device (terminal device) 3. The gas detection device 1 detects gas generated from the subject's sample. The detected gas can be used for analyzing the subject's health status, etc. Here, the subject's sample may be, for example, a part of the subject's tissue or urine, but in this embodiment, it is the subject's stool. The chemical substance that is the target of detection by the gas sensor group 24, which will be described later, and that can exist as a gas is referred to as the "detection target gas." The detection target gas may be one type or multiple types. The detection target gas may be, for example, contained in the gas (sample gas) excreted from the subject's stool. The concentration of the detection target gas refers to the concentration of the target chemical substance in the sample gas.

[0010] The gas detection device 1 is installed, for example, in a flush toilet 2, as shown in Figure 1. The toilet 2 comprises a toilet bowl 2A and a toilet seat 2B. The gas detection device 1 may be installed at any location on the toilet 2. For example, as shown in Figure 1, the gas detection device 1 may be positioned from between the toilet bowl 2A and the toilet seat 2B to the outside of the toilet 2. Part of the gas detection device 1 may be embedded in the toilet seat 2B. The subject's feces may be discharged into the toilet bowl 2A of the toilet 2. The gas detection device 1 can acquire a sample gas in which the gas generated from the feces discharged into the toilet bowl 2A is mixed with outside air. The gas detection device 1 can detect the type and concentration of the target gas contained in the sample gas. The gas detection device 1 can transmit the detection results to the electronic device 3.

[0011] The toilet bowl 2 may be installed in a toilet room in a house or hospital, etc. The electronic device 3 is, for example, a smartphone used by the subject. However, the electronic device 3 is not limited to a smartphone and may be any electronic device. The electronic device 3 may be located inside or outside the toilet room.

[0012] Electronic device 3 may receive detection results from gas detection device 1 via wireless or wired communication. In this case, electronic device 3 may receive detection results from gas detection device 1 via a server. Electronic device 3 may display the received detection results on display unit 3A. Display unit 3A may include a display capable of displaying characters, etc., and a touchscreen capable of detecting contact by the user's (subject's) finger, etc. The display may include a display device such as a liquid crystal display (LCD), organic electroluminescent display (OELD), or inorganic electroluminescent display (IELD). The detection method for the touchscreen may be any method such as a capacitive method, resistive method, surface acoustic wave method, ultrasonic method, infrared method, electromagnetic induction method, or load detection method.

[0013] <Gas detection device 1> Figure 2 is a schematic diagram showing an example of the configuration of a gas detection device 1 according to one embodiment. Figure 3 is a block diagram showing an example of the configuration of the gas detection device 1. As described above, the gas detection device 1 is installed in a toilet bowl 2 and can collect a sample gas containing gas expelled from the subject's stool, and can detect the type and concentration of the target gas contained in the sample gas. The gas detection device 1 can also transmit information indicating the type and concentration of the detected target gas as a detection result to an electronic device 3. As shown in Figures 2 and 3, the gas detection device 1 comprises a housing 10, a sampling unit 21 (sample gas sampling unit), a storage pump 22, a storage tank 25, a sensor chamber 23 (gas detection unit), a group of gas sensors 24, a chamber pump 26, a discharge passage 30, a control unit 40, a subject detection unit 50, a communication unit 51, and a storage unit 52.

[0014] (Cabinet 10) The housing 10 houses various components of the gas detection device 1. The housing 10 may be made of any material. For example, the housing 10 may be made of a material such as metal or resin.

[0015] [Collection section 21] The sampling unit 21 is a tubular member that collects sample gas from the target space and supplies the collected sample gas into the storage tank 25. The sampling unit 21 is exposed on the inside of the toilet bowl 2A and has an opening 211 that opens toward the inside of the toilet bowl 2A. The sample gas from the toilet bowl 2A, which is the target space, is collected by the operation of the storage pump 22 (described later). The sampling unit 21 also has a sample flow path inside for flowing the sample gas. Here, the sample flow path is intended to be the flow path through which the collected sample gas moves. The sample flow path connects the opening 211 and the sensor chamber 23.

[0016] [Storage pump 22] The storage pump 22 is a pump located on the sample flow path. The storage pump 22 may operate according to the control of a pump control unit 41 (described later). As an example, the storage pump 22 may be a pump that operates at a constant air supply rate. The storage pump 22 may supply sample gas from the sampling unit 21 into the storage tank 25.

[0017] [Storage tank 25] The storage tank 25 is located behind the storage pump 22 on the sample flow path and temporarily stores the sample gas collected by the storage pump 22 from the sampling unit 21. However, the function of the storage tank 25 is not limited to temporarily storing the sample gas and may function as a part of the flow path that does not store the sample gas. The storage tank 25 may be formed in a bag shape by resin or may be formed in a cylindrical or rectangular shape by metal.

[0018] [Sensor chamber 23] The sensor chamber 23 is a chamber that houses the gas sensor group 24 inside. The sensor chamber 23 communicates with the storage tank 25. The number of gas sensors included in the gas sensor group 24 housed inside the sensor chamber 23 is not particularly limited. The gas sensor group 24 may include any number of gas sensors according to the type and number of the detected gas.

[0019] [Gas sensor group 24] The gas sensor group 24 includes a first gas sensor 24a and a second gas sensor 24b. Both the first gas sensor 24a and the second gas sensor 24b are gas sensors capable of detecting both the first detected gas and the second detected gas. That is, both the first gas sensor 24a and the second gas sensor 24b take the first detected gas and the second detected gas as the detected gas. Hereinafter, the detection signal output from the first gas sensor 24a is referred to as the first detection signal. Also, the detection signal output from the second gas sensor 24b is referred to as the second detection signal.

[0020] The gas sensor group 24 can be any collection of sensors that output different detection signals depending on the concentration of the target gas. In the following description, the sensors constituting the gas sensor group 24 will be described using, as an example, sensors whose detection signal intensity changes depending on the concentration of the target gas, but the system is not limited to these. For example, the sensors constituting the gas sensor group 24 can output a detection signal with an intensity corresponding to the concentration of the target gas that may be contained in the sample gas to the signal acquisition unit 42 of the control unit 40. As shown in Figure 2, the gas detection device 1 may include multiple gas sensors. Furthermore, each of the multiple gas sensors may be capable of outputting a detection signal corresponding to the concentration of different types of target gases. This allows the gas detection device 1 to analyze the concentrations of multiple types of target gases.

[0021] The first and second detected gases may both be gases containing a sulfur atom in their compositional formula. A sensor that is sensitive to one type of gas containing a sulfur atom in its compositional formula tends to be sensitive to another type of gas containing a sulfur atom in its compositional formula. Therefore, when a sample gas contains multiple types of target gases containing a sulfur atom in their compositional formula, it is difficult to detect the concentration of any of these multiple target gases with a single gas sensor. With the gas detection device 1, instead of detecting the individual concentrations of multiple target gases containing a sulfur atom in their compositional formula, the concentrations can be accurately estimated based on the first and second detection signals, as described later.

[0022] Specifically, the first gas to be detected may be hydrogen sulfide. The second gas to be detected may be methyl mercaptan. Hydrogen sulfide and methyl mercaptan are gases that are particularly difficult to detect individually using a single gas sensor. With the gas detection device 1, instead of detecting the individual concentrations of hydrogen sulfide and methyl mercaptan, the concentrations can be accurately estimated based on the first and second detection signals, as described later. However, the first and second gases to be detected may be gases other than hydrogen sulfide and methyl mercaptan that contain a sulfur atom in their compositional formula.

[0023] Furthermore, the first and second detected gases are not limited to gases containing sulfur atoms in their compositional formula. For example, both the first and second detected gases may contain nitrogen atoms. Even when the sample gas contains multiple types of target gases that contain nitrogen atoms in their compositional formula, it is difficult to detect the concentration of any of these multiple target gases with a single gas sensor. With the gas detection device 1, instead of detecting the individual concentrations of multiple target gases that contain nitrogen atoms in their compositional formula, the concentrations can be accurately estimated based on the first and second detection signals, as described later.

[0024] Figure 4 is a graph showing examples of fluctuations in the first detection signal output from the first gas sensor 24a due to hydrogen sulfide and methyl mercaptan. In Figure 4, the horizontal axis represents time, and the vertical axis represents the first detection signal (voltage). In Figure 4, reference numeral 401 is a graph showing an example of fluctuations in the first detection signal due to hydrogen sulfide at a concentration of 0.3 ppm. In Figure 4, reference numeral 402 is a graph showing an example of fluctuations in the first detection signal due to methyl mercaptan at a concentration of 0.3 ppm. Period T1 in Figure 4 is the period during which hydrogen sulfide or methyl mercaptan was supplied to the first gas sensor 24a. Period T2 in Figure 4 is the period during which the supply of hydrogen sulfide or methyl mercaptan to the first gas sensor 24a was stopped, and the hydrogen sulfide or methyl mercaptan that had been supplied up to that point was removed using, for example, external air or nitrogen.

[0025] As shown by reference numeral 401 in Figure 4, the first detection signal shows a clear variation due to hydrogen sulfide between period T1 and period T2. On the other hand, as shown by reference numeral 402 in Figure 4, the first detection signal shows a slight variation due to methyl mercaptan between period T1 and period T2, but it is small compared to the variation due to hydrogen sulfide. In other words, the detection sensitivity of the first gas sensor 24a to hydrogen sulfide is greater than the detection sensitivity of the first gas sensor 24a to methyl mercaptan.

[0026] Figure 5 is a graph showing examples of fluctuations in the second detection signal output from the second gas sensor 24b due to hydrogen sulfide and methyl mercaptan. In Figure 5, the horizontal axis represents time, and the vertical axis represents the second detection signal (voltage). In Figure 5, reference numeral 501 is a graph showing an example of fluctuations in the second detection signal due to hydrogen sulfide at a concentration of 0.3 ppm. In Figure 5, reference numeral 502 is a graph showing an example of fluctuations in the second detection signal due to methyl mercaptan at a concentration of 0.3 ppm. Period T3 in Figure 5 is the period during which hydrogen sulfide or methyl mercaptan was supplied to the second gas sensor 24b. Period T4 in Figure 5 is the period during which the supply of hydrogen sulfide or methyl mercaptan to the first gas sensor 24a was stopped, and the hydrogen sulfide or methyl mercaptan that had been supplied up to that point was removed using, for example, external air or nitrogen.

[0027] As shown by reference numeral 502 in Figure 5, the second detection signal shows a clear variation due to methyl mercaptan between period T3 and period T4. On the other hand, as shown by reference numeral 501 in Figure 5, the second detection signal shows some variation due to hydrogen sulfide between period T3 and period T4, but it is small compared to the variation due to methyl mercaptan. In other words, the detection sensitivity of the second gas sensor 24b to methyl mercaptan is greater than the detection sensitivity of the second gas sensor 24b to hydrogen sulfide.

[0028] As shown in Figures 4 and 5, the relative relationship between the detection sensitivity of the first gas sensor 24a and the second gas sensor 24b for hydrogen sulfide and the detection sensitivity for methyl mercaptan may be different from each other. Specifically, when the concentrations of hydrogen sulfide and methyl mercaptan are equal, the ratio of the intensity of the first detection signal caused by methyl mercaptan to the intensity of the first detection signal caused by hydrogen sulfide may be smaller than the ratio of the intensity of the second detection signal caused by methyl mercaptan to the intensity of the second detection signal caused by hydrogen sulfide. By including such first gas sensors 24a and second gas sensors 24b in the gas sensor group 24, the concentrations of hydrogen sulfide and methyl mercaptan can be estimated with high accuracy, as will be described later.

[0029] [Chamber pump 26] The chamber pump 26 is a pump that introduces the sample gas from the storage tank 25 to the sensor chamber 23. The chamber pump 26 may operate according to the control of the pump control unit 41 (described later). The chamber pump 26 may be, for example, a pump that operates at a constant air supply rate. Also, the discharge rate of the chamber pump 26 may be set to be smaller than the discharge rate of the storage pump 22.

[0030] (Exhaust channel 30) The discharge passage 30 may be composed of a tubular member such as a resin tube or a metal or glass pipe. The discharge passage 30 connects the sensor chamber 23 to the outside of the housing 10. The chamber pump 26 may be located in the middle of the discharge passage 30. The discharge passage 30 discharges the exhaust gas from the sensor chamber 23 to the outside of the gas detection device 1 through the operation of the chamber pump 26. A portion of the discharge passage 30 may be exposed to the outside of the toilet bowl 2A, as shown in Figure 1.

[0031] (Control Unit 40) The control unit 40 controls the operation of each part of the gas detection device 1 and estimates the concentration of the target gas contained in the sample gas. As shown in Figure 3, the control unit 40 comprises a pump control unit 41, a signal acquisition unit 42, and an estimation unit 43.

[0032] [Pump control unit 41] The pump control unit 41 controls the operation of the storage pump 22 and the chamber pump 26. Specifically, the pump control unit 41 operates the storage pump 22 and the chamber pump 26 according to the detection result of the subject detection unit 50 (described later), and stops them after a predetermined time has elapsed. As a result, the sample gas in the toilet bowl 2A is drawn from the sampling unit 21 and supplied to the sensor chamber 23 via the storage tank 25.

[0033] [Signal acquisition unit 42] The signal acquisition unit 42 acquires detection signals from each gas sensor in the gas sensor group 24, corresponding to the type and concentration of the target gas contained in the sample gas. Specifically, the signal acquisition unit 42 may acquire detection signals output from each gas sensor in the gas sensor group 24 when the operation of the storage pump 22 and the chamber pump 26 by the pump control unit 41 stops.

[0034] [Estimation part 43] The estimation unit 43 estimates the type and concentration of the target gas contained in the sample gas based on the detection signals acquired by the signal acquisition unit 42 from each gas sensor included in the gas sensor group 24. The detection signals acquired from each gas sensor are, in other words, the detection signals output from the gas sensors. The estimation unit 43 may estimate the concentrations of the first and second target gases based on the first detection signal output from the first gas sensor 24a and the second detection signal output from the second gas sensor 24b. As described above, both the first gas sensor 24a and the second gas sensor 24b are capable of detecting both the first and second target gases. Therefore, it is not possible to uniquely estimate the combination of concentrations of the first and second target gases based on only one of the first or second detection signals. As described above, the first gas sensor 24a and the second gas sensor 24b have different relative detection sensitivities for the first and second target gases. Therefore, the estimation unit 43 can uniquely estimate a combination of the concentration of the first detected gas and the concentration of the second detected gas that is consistent with both the first detection signal and the second detection signal.

[0035] The estimation unit 43 may be provided in the control unit 40 of the gas detection device 1, as shown in Figure 3. Alternatively, the estimation unit 43 may not be provided in the control unit 40, but rather on a cloud connected to the gas detection device 1 via a network. If the estimation unit 43 is on a cloud, the signal acquisition unit 42 may transmit the detection signals acquired from each gas sensor included in the gas sensor group 24 to the cloud via the network. The estimation unit 43 on the cloud may estimate the type and concentration of the target gas based on the detection signals transmitted from the signal acquisition unit 42.

[0036] The estimation unit 43 may estimate the concentrations of the first and second detected gases contained in the sample gas using a concentration estimation model created from first and second detection signals for multiple types of training gases. The training gas is a sample gas containing the first and second detected gases whose concentrations are known. The concentration estimation model may be created by machine learning using a pair of first and second detection signals for the training gas and the concentrations of the first and second detected gases contained in the training gas. The estimation unit 43 can easily perform estimation by estimating the concentrations of the first and second detected gases using such a concentration estimation model.

[0037] (Person detection unit 50) The subject detection unit 50 may include at least one of the following: an image camera (not shown), a personal identification switch, an infrared sensor, and a pressure sensor. The subject detection unit 50 outputs the detection result to the control unit 40.

[0038] For example, if the subject detection unit 50 includes an infrared sensor, it can detect that a subject has entered the toilet room by detecting the reflected light from an object irradiated with infrared light by the infrared sensor. As a result of the detection, the subject detection unit 50 outputs a signal to the control unit 40 indicating that a subject has entered the toilet room.

[0039] For example, if the subject detection unit 50 is configured to include a pressure sensor, it can detect that a subject has sat on the toilet seat 2B by detecting an increase in pressure on the toilet seat 2B shown in Figure 1. As a result of the detection, the subject detection unit 50 outputs a signal to the control unit 40 indicating that a subject has sat on the toilet seat 2B.

[0040] For example, if the subject detection unit 50 includes a pressure sensor, it can detect that the subject has stood up from the toilet seat 2B by detecting a decrease in the pressure on the toilet seat 2B shown in Figure 1. As a result of the detection, the subject detection unit 50 outputs a signal to the control unit 40 indicating that the subject has stood up from the toilet seat 2B.

[0041] For example, if the subject detection unit 50 is configured to include an image camera and a personal identification switch, it collects data such as facial images, sitting height, and weight. The subject detection unit 50 identifies and detects individuals from the collected data. As a result of the detection, the subject detection unit 50 outputs a signal to the control unit 40 indicating the identified individual.

[0042] For example, if the subject detection unit 50 is configured to include a personal identification switch, it identifies (detects) an individual based on the operation of the personal identification switch. In this case, personal information may be pre-registered (stored) in the storage unit 52. As a result of the detection, the subject detection unit 50 outputs a signal indicating the identified individual to the control unit 40.

[0043] Furthermore, the subject detection unit 50 may detect that the subject has defecated. As a result of the detection, the subject detection unit 50 outputs a signal to the control unit 40 indicating that the subject has defecated.

[0044] (Communications Section 51) The communication unit 51 communicates with the electronic device 3, which displays the analysis results of the target gas detected by the control unit 40 to the subject, for example, on the display unit 3A or by voice. The communication unit 51 may also be able to communicate with an external server. The communication method used in communication between the communication unit 51, the electronic device 3, and the external server may be a short-range wireless communication standard or a wireless communication standard that connects to a mobile phone network, or a wired communication standard. Short-range wireless communication standards may include, for example, WiFi (registered trademark), Bluetooth (registered trademark), infrared, and NFC (Near Field Communication). Wireless communication standards that connect to a mobile phone network may include, for example, LTE (Long Term Evolution) or a fourth-generation or higher mobile communication system. Furthermore, the communication method used in communication between the communication unit 51, the electronic device 3, and the external server may be a communication standard such as LPWA (Low Power Wide Area) or LPWAN (Low Power Wide Area Network).

[0045] (Storage unit 52) The storage unit 52 is composed of, for example, a semiconductor memory or a magnetic memory. The storage unit 52 stores various information and a program for operating the gas detection device 1. The storage unit 52 may function as a work memory. The storage unit 52 may also store, for example, a concentration estimation model for the estimation unit 43 to estimate the concentrations of the first detected gas and the second detected gas.

[0046] <Effects of Gas Detection Device 1> Conventionally, depending on the type of gas to be detected, it was not possible to accurately measure the concentration with a single sensor. In contrast, the gas detection device 1 may include a sampling unit 21, a storage pump 22, a storage tank 25, a sensor chamber 23, a group of gas sensors 24, a chamber pump 26, and a control unit 40. In particular, the group of gas sensors 24 may include a first gas sensor 24a and a second gas sensor 24b. Furthermore, the control unit 40 may include an estimation unit 43.

[0047] According to the above configuration, in the gas detection device 1, the concentration of the target gas contained in the sample gas is detected by a group of gas sensors 24 including a first gas sensor 24a and a second gas sensor 24b. Both the first gas sensor 24a and the second gas sensor 24b may be gas sensors capable of detecting both the first gas to be detected and the second gas to be detected. Based on the first detection signal output by the first gas sensor 24a and the second detection signal output by the second gas sensor 24b, the estimation unit 43 estimates the concentrations of the first gas to be detected and the second gas to be detected. As a result, the gas detection device 1 can estimate the concentration with high accuracy for gases whose concentration is difficult to measure accurately with a single sensor.

[0048] [Embodiment 2] Other embodiments of this disclosure are described below. For convenience of explanation, components having the same function as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are not repeated.

[0049] In the gas detection device 1, both the first gas sensor 24a and the second gas sensor 24b may be electrochemical sensors. By using electrochemical sensors for both the first gas sensor 24a and the second gas sensor 24b, the concentrations of the first and second gases to be detected can be detected with high sensitivity.

[0050] In the gas detection device 1, the first gas sensor 24a and the second gas sensor 24b are not limited to electrochemical sensors, but may be, for example, semiconductor sensors, quartz crystal microbalance (QCM) sensors, CMOS (Complementary Metal Oxide Semiconductor) sensors, sensitive film sensors, optical sensors, or photoacoustic sensors. As the sensitive film sensor, a sensitive film stress sensor or a sensitive film resonance sensor may be used. The gas sensor group 24 may include multiple types of sensors. The first gas sensor 24a and the second gas sensor 24b may be selected according to the first and second gases to be detected.

[0051] Figure 6 is a partial cross-sectional view showing an example of the configuration of the first gas sensor 24a included in the gas sensor group 24. The second gas sensor 24b may have the same configuration as the first gas sensor 24a, and is therefore not shown. As shown in Figure 6, the first gas sensor 24a may include a case 241, a first electrode 244, a second electrode 245, and an electrode pin 246.

[0052] Case 241 is a housing that contains the first electrode 244 (electrode), the second electrode 245 (electrode), and the electrolyte. A reference electrode may be provided between the first electrode 244 and the second electrode 245. Case 241 has a vent hole 242 formed inside for taking in sample gas. The vent hole 242 may be provided with a pre-filter 243 to reduce the entry of foreign matter such as dust into Case 241.

[0053] The first electrode 244 and the second electrode 245 may be positioned opposite each other within the case 241, for example. The first electrode 244 may be positioned on the side of the ventilation hole 242, for example. In that case, the second electrode 245 may be installed on the side of the case 241 opposite to the first electrode 244, for example. Also, if the first electrode 244 and the second electrode 245 are adjacent to each other, a nonwoven fabric may be placed between them.

[0054] In the first gas sensor 24a, the first electrode 244 and the second electrode 245 are electrically connected to each other via an electrolyte. The first electrode 244, the second electrode 245, and the electrolyte constitute an electrode unit that outputs a signal corresponding to the concentration of the target gas contained in the sample gas. The first electrode 244 and the second electrode 245 may be electrodes mainly composed of carbon. The electrolyte may, for example, be mainly composed of sulfuric acid, but is not limited to this.

[0055] When the sample gas taken into the case 241 through the vent hole 242 comes into contact with the electrolyte, a portion of the sample gas dissolves in the electrolyte, causing a change in the resistance between the first electrode 244 and the second electrode 245. The degree of change in resistance varies depending on the type and concentration of gas contained in the sample gas. As a result, the voltage between the first electrode 244 and the second electrode 245 changes according to the type and concentration of gas contained in the sample gas. This change in voltage serves as a signal indicating the type and concentration of gas contained in the sample gas.

[0056] The electrode pin 246 is a pin for extracting signals output from the first electrode 244 and the second electrode 245 to the outside. The first gas sensor 24a may include an electrode pin 246 connected to the first electrode 244 and an electrode pin 246 connected to the second electrode 245. The electrode pin 246 may be made of platinum, for example, but is not limited to that.

[0057] [Embodiment 3] Further embodiments of this disclosure are described below.

[0058] Figure 7 is a schematic diagram showing an example of the configuration of the gas detection device 1A according to Embodiment 3. As shown in Figure 7, the gas detection device 1A differs from the gas detection device 1 only in that the gas sensor group 24 further includes a third gas sensor 24c.

[0059] The third gas sensor 24c is a gas sensor capable of detecting the first and second gases to be detected. The detection sensitivity of the third gas sensor 24c for the first gas may differ from that of the first gas sensor 24a and the second gas sensor 24b. By including the third gas sensor 24c, the gas detection device 1A can obtain three different detection signals for the first and second gases to be detected. Therefore, the concentrations of the first and second gases to be detected can be estimated with higher accuracy.

[0060] [Embodiment 4] Further embodiments of this disclosure are described below.

[0061] In Embodiment 4, the types of gases used for the first and second detected gases differ from those used in Embodiment 1. In Embodiment 4, the first detected gas may be hydrogen sulfide or methyl mercaptan. The second detected gas may be hydrogen, water, ammonia, or alcohol.

[0062] The second detected gas described above is a gas that causes noise or interferes with the output signal from the gas sensor that detects the first detected gas described above. In other words, the concentration of the second detected gas affects the detection signal from the gas sensor that detects the first detected gas. For this reason, in an environment where the second detected gas described above is present, it is difficult to detect the concentration of the first detected gas with a single gas sensor.

[0063] In Embodiment 4, when the concentrations of the first detected gas and the second detected gas are equal, the ratio of the intensity of the second detection signal caused by the second detected gas to the intensity of the second detection signal caused by the first detected gas may be greater than 1. When the concentrations of the first detected gas and the second detected gas are substantially equal, the ratio of the intensity of the second detection signal caused by the second detected gas to the intensity of the second detection signal caused by the first detected gas may be greater than 10. That is, the second gas sensor 24b may be a gas sensor that primarily detects the second detected gas. By providing such a second gas sensor 24b in the gas detection device 1, the estimation unit 43 can accurately estimate the concentration of the second detected gas based on the second detection signal. In other words, the estimation unit 43 can also accurately estimate the magnitude of the influence of the concentration of the second detected gas on the first detection signal. Therefore, the estimation unit 43 can accurately estimate the concentration of the first detected gas based on the first detection signal.

[0064] In Embodiment 4, the second detection signal output from the second gas sensor 24b has little influence on the estimation of the concentration of the first detected gas. Generally, such a second detection signal is not used as an explanatory variable in the concentration estimation model for the first detected gas.

[0065] However, in machine learning for creating a concentration estimation model for estimation by the estimation unit 43, the second detection signal may also be used as an explanatory variable in the concentration estimation model of the first detected gas. By using the second detection signal as an explanatory variable in the concentration estimation model of the first detected gas, the influence of the concentration of the second detected gas on the first detection signal can be reduced, and the concentration of the first detected gas can be estimated with greater accuracy.

[0066] [Embodiment 5] Further embodiments of this disclosure are described below.

[0067] Figure 8 is a schematic diagram showing an example of the configuration of the gas detection device 1B according to Embodiment 5. As shown in Figure 8, the gas detection device 1B differs from the gas detection device 1 in that the sensor chamber 23 is located downstream of the chamber pump 26. Even with such a gas detection device 1B, it is possible to estimate the concentration with high accuracy for gases whose concentration is difficult to measure accurately with a single sensor.

[0068] [Examples of implementation using software] The functions of the gas detection devices 1, 1A, and 1B (hereinafter referred to as "devices") can be realized by programs that cause a computer to function as the device, and by programs that cause a computer to function as each control block of the device (particularly each part included in the control unit 40).

[0069] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., memory) as hardware for executing the program. By executing the program using this control device and storage device, the functions described in each of the embodiments are realized.

[0070] The above program may be recorded on one or more computer-readable recording media, not temporary ones. These recording media may or may not be provided by the above device. In the latter case, the program may be supplied to the above device via any wired or wireless transmission medium.

[0071] Furthermore, some or all of the functions of each of the above control blocks can also be implemented by logic circuits. For example, an integrated circuit in which logic circuits functioning as each of the above control blocks are formed is also included in the scope of this disclosure. In addition, it is also possible to implement the functions of each of the above control blocks by, for example, a quantum computer.

[0072] Furthermore, each process described in the above embodiments may be performed by AI (Artificial Intelligence). In this case, the AI ​​may operate on the control device described above, or it may operate on other devices (for example, an edge computer or a cloud server).

[0073] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. [Explanation of symbols]

[0074] 1,1A,1B Gas detection device 21. Sampling Section (Sample Gas Sampling Section) 23 Sensor Chamber (Gas Detection Unit) 24a First gas sensor 24b Second gas sensor 24C Third Gas Sensor 244 1st electrode (electrode) 245 Second electrode (electrode) 43 Estimation part

Claims

1. A sample gas sampling unit collects a sample gas containing the first detected gas and the second detected gas into a storage tank, A gas detection unit comprising a plurality of gas sensors, including a first gas sensor and a second gas sensor, capable of detecting both the first gas to be detected and the second gas to be detected contained in the sample gas, A sensor chamber housing the gas detection unit inside, A chamber pump that introduces the sample gas from the storage tank to the sensor chamber and exhausts the sample gas from the sensor chamber to the outside, A control unit that controls the chamber pump, Equipped with, The control unit controls the chamber pump to repeat the introduction and exhaust of gases, and is a gas detection device.

2. A gas detection device according to claim 1, A gas detection device in which the first gas sensor and the second gas sensor have different relative detection sensitivities for the first gas to be detected and for the second gas to be detected.

3. A gas detection device according to claim 2, The ratio of the intensity of the first detection signal output from the first gas sensor due to the first detected gas to the intensity of the first detection signal due to the second detected gas is: A gas detection device in which the ratio of the intensity of the second detection signal caused by the second detected gas to the intensity of the second detection signal output from the second gas sensor caused by the first detected gas is smaller.

4. A gas detection device according to claim 2 or 3, A gas detection device in which both the first gas sensor and the second gas sensor are electrochemical sensors or semiconductor sensors.

5. A gas detection device according to claim 1, A gas detection device in which the first gas to be detected and the second gas to be detected are either gases that both contain sulfur atoms in their compositional formula, or gases that both contain nitrogen atoms.

6. A gas detection device according to claim 5, The first detected gas is hydrogen sulfide. The second gas to be detected is methyl mercaptan, according to the gas detection device.

7. A gas detection device according to claim 1, The first detected gas is hydrogen sulfide or methyl mercaptan. The second gas to be detected is hydrogen, water, ammonia, or alcohol, and the gas detection device is used.

8. A gas detection device according to claim 1, The sample gas collection unit is a gas detection device that collects the sample gas into the storage tank, which is formed in the shape of a bag.

9. A gas detection device according to claim 3, The control unit is a gas detection device that, after stopping the operation of the chamber pump, acquires the first detection signal from the first gas sensor and the second detection signal from the second gas sensor.

10. A sample gas sampling unit collects a sample gas containing the first detected gas and the second detected gas into a storage tank, A gas detection unit comprising a plurality of gas sensors, including a first gas sensor and a second gas sensor, capable of detecting both the first gas to be detected and the second gas to be detected contained in the sample gas, A sensor chamber housing the gas detection unit inside, A chamber pump that introduces the sample gas from the storage tank to the sensor chamber and exhausts the sample gas from the sensor chamber to the outside, A control unit that controls the chamber pump, An estimation unit estimates the concentrations of the first detected gas and the second detected gas based on a first detection signal output from the first gas sensor and a second detection signal output from the second gas sensor. Equipped with, The control unit controls the chamber pump to repeat the introduction and exhaust of gases, and is a gas detection system.

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