Physical quantity measurement system

Abstract

The present disclosure addresses the problem of measuring the concentration of a gas contained in a mixed gas using a measuring method different from conventional measuring methods. A physical quantity measurement system (1) comprises a flow passage, a pair of ultrasonic transceivers (11, 12), a temperature sensor (13), a first acquiring unit (203), a second acquiring unit (204), a third acquiring unit (205), and a concentration measuring unit (206). The first acquiring unit (203) acquires a measured propagation time corresponding to a reference temperature. The second acquiring unit (204) acquires a first reference propagation time of ultrasound waves for a case in which at least a first gas is flowing through the flow passage and a second gas is not flowing. The third acquiring unit (205) acquires a second reference propagation time of ultrasound waves for a case in which at least the second gas is flowing through the flow passage and the first gas is not flowing. The concentration measuring unit (206) measures the concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time.

Description

Physical Quantity Measurement System

[0001] The present disclosure generally relates to a physical quantity measurement system, and more particularly to a physical quantity measurement system that measures a gas mixture flowing through a flow path.

[0002] In fields that use fuel cells, such as fuel cell vehicles (FCVs), it is necessary to measure the flow rate and concentration of hydrogen in high-humidity hydrogen mixed gases.

[0003] 2. Description of the Related Art Conventionally, a method for measuring the concentration of a mixed gas containing hydrogen has been known that utilizes ultrasonic waves (see, for example, Patent Document 1).

[0004] This device first calculates the speed of sound in the mixed gas from the measured propagation time of the ultrasonic waves, and then calculates the average molecular weight of the mixed gas using this value and the measured temperature. Next, the concentration of hydrogen, a component gas, is calculated using the known molecular weights of each component gas.

[0005] JP 2010-91489 A

[0006] In recent years, there has been a demand for a measurement method that differs from the conventional method for determining the hydrogen concentration (gas concentration) contained in a mixed gas (mixed gas).

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a physical quantity measurement system that can measure the concentration of gases contained in a mixed gas using a measurement method that differs from conventional measurement methods.

[0008] A physical quantity measuring system according to one aspect of the present disclosure includes a flow path, a pair of ultrasonic transmitter-receivers, a temperature sensor, a first acquisition unit, a second acquisition unit, a third acquisition unit, and a concentration measurement unit. A mixed gas containing a first gas and a second gas flows through the flow path. The pair of ultrasonic transmitter-receivers transmit and receive ultrasonic waves and are arranged so that the ultrasonic waves cross the flow of the mixed gas in the flow path. The temperature sensor measures the temperature of the mixed gas. The first acquisition unit acquires a measured propagation time corresponding to the reference temperature based on the propagation time of the ultrasonic waves obtained by transmitting and receiving the ultrasonic waves between the pair of ultrasonic transmitter-receivers, the temperature measured by the temperature sensor, and a reference temperature. The second acquisition unit acquires a first reference propagation time of the ultrasonic waves when at least the first gas is flowing through the flow path and the second gas is not flowing. The third acquisition unit acquires a second reference propagation time of the ultrasonic waves when at least the second gas is flowing through the flow path and the first gas is not flowing. The concentration measurement unit measures the concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time.

[0009] FIG. 1 is a block diagram showing the configuration of a physical quantity measurement system according to a first embodiment. FIG. 2 is a system diagram showing the configuration of the physical quantity measurement system according to the same. FIG. 3 is a cross-sectional view in the XY plane of a flow path main body provided in the physical quantity measurement system according to the same. FIG. 4 is a flowchart showing the operation of the physical quantity measurement system according to the same. FIG. 5 is a block diagram showing the configuration of a physical quantity measurement system according to a second embodiment. FIG. 6 is a cross-sectional view in the XY plane of a flow path main body provided in the physical quantity measurement system according to the same. FIG. 7 is a flowchart showing the operation of the physical quantity measurement system according to the same. FIG. 8 is a block diagram showing the configuration of a physical quantity measurement system according to a third embodiment.

[0010] The embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and modifications. Various modifications other than the following embodiments and modifications are possible depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure.

[0011] First Embodiment A physical quantity measuring system 1 according to a first embodiment will be described below with reference to FIGS.

[0012] (1) Overview The physical quantity measurement system 1 of this embodiment is a system that measures the concentration of a specific gas (e.g., hydrogen) from a mixed gas containing multiple gases (e.g., hydrogen, nitrogen) flowing through a flow path 101 (see FIG. 3 ) and the concentration of at least the specific gas among the flow rates of the mixed gas.

[0013] As shown in FIGS. 1 and 3 , the physical quantity measuring system 1 of this embodiment includes a flow path 101, a pair of ultrasonic transmitters / receivers 11 and 12, a temperature sensor 13, a first acquisition unit 203, a second acquisition unit 204, a third acquisition unit 205, and a concentration measurement unit 206. A mixed gas containing a first gas and a second gas flows through the flow path 101. The pair of ultrasonic transmitters / receivers 11 and 12 transmit and receive ultrasonic waves and are arranged so that the ultrasonic waves cross the flow of the mixed gas in the flow path 101. The temperature sensor 13 measures the temperature of the mixed gas. The first acquisition unit 203 acquires a measured propagation time corresponding to a reference temperature based on the propagation time of the ultrasonic waves obtained by transmitting and receiving the ultrasonic waves between the pair of ultrasonic transmitters / receivers 11 and 12, the temperature measured by the temperature sensor 13, and a reference temperature. The second acquisition unit 204 acquires a first reference propagation time of the ultrasonic waves when at least the first gas flows through the flow path 101 and the second gas does not flow. The third acquisition unit 205 acquires a second reference propagation time of the ultrasonic wave when at least the second gas is flowing and the first gas is not flowing through the flow path 101. The concentration measurement unit 206 measures the concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time.

[0014] According to this configuration, the concentration of the first gas is measured using the measured propagation time, the first reference propagation time, and the second reference propagation time, so that the concentration of the gas contained in the mixed gas can be measured using a measurement method different from conventional measurement methods.

[0015] (2) Configuration The detailed configuration of the physical quantity measuring system 1 will be described below with reference to FIGS. 1 to 3. FIG.

[0016] 1, the physical quantity measurement system 1 includes a flow path main body 10 and a processing device 20. The physical quantity measurement system 1 measures, as physical quantities, the concentration of a first gas (e.g., hydrogen) contained in a mixed gas flowing through the flow path main body 10 and the flow rate of the mixed gas. Here, the concentration measured by the physical quantity measurement system 1 is, for example, a volume concentration.

[0017] An X-axis, a Y-axis, and a Z-axis are defined for the flow path body 10 (see FIG. 2). The X-axis is an axis along the longitudinal direction of the flow path body 10, i.e., an axis along the direction in which the mixed gas flows. The Y-axis is an axis perpendicular to the X-axis, for example, an axis along the depth direction of the flow path body 10. The Z-axis is an axis perpendicular to both the X-axis and the Y-axis, for example, an axis along the height direction of the flow path body 10. FIG. 3 is a cross-sectional view of the flow path body 10 in the X-Y plane. Note that in FIG. 3, the pair of ultrasonic transmitter / receivers 11, 12 and the temperature sensor 13 are not shown in cross section.

[0018] (2.1) Flow Channel Main Body A mixed gas flows through the flow channel main body 10. As shown in Fig. 1, the flow channel main body 10 has a pair of ultrasonic transmitters and receivers 11 and 12, and a temperature sensor 13. Furthermore, as shown in Fig. 2, the flow channel main body 10 further has a main body portion 100. In the following description, the ultrasonic transmitter and receiver 11 may be referred to as the first ultrasonic transmitter and receiver 11, and the ultrasonic transmitter and receiver 12 may be referred to as the second ultrasonic transmitter and receiver 12.

[0019] The main body 100 is formed in a substantially rectangular shape. A flow path 101 is formed in the center of the main body 100, through which a fluid to be measured (a mixed gas), such as a mixed gas containing a first gas and a second gas, flows (see FIG. 3 ). A first opening 110 and a second opening 111 are provided at both longitudinal ends of the main body 100. Specifically, the first opening 110 and the second opening 111 are provided on both longitudinally opposing side surfaces of the main body 100. The first opening 110 and the second opening 111 are connected by the flow path 101. The mixed gas flows in through the first opening 110, passes through the flow path 101, and flows out through the second opening 111. As described above, the mixed gas contains the first gas and the second gas. Both the first gas and the second gas have the same molecular structure (e.g., a monoatomic molecule or a diatomic molecule). Here, both the first gas and the second gas are diatomic molecules. For example, the first gas is hydrogen and the second gas is nitrogen.

[0020] The pair of ultrasonic transmitters / receivers 11, 12 transmit and receive ultrasonic waves. The pair of ultrasonic transmitters / receivers 11, 12 are arranged so that the ultrasonic waves cross the flow of the mixed gas in the flow channel 101. Specifically, the first ultrasonic transmitter / receiver 11 transmits (transmits) ultrasonic waves toward the second ultrasonic transmitter / receiver 12. The first ultrasonic transmitter / receiver 11 receives (receives) ultrasonic waves transmitted from the second ultrasonic transmitter / receiver 12. The second ultrasonic transmitter / receiver 12 transmits (transmits) ultrasonic waves toward the first ultrasonic transmitter / receiver 11. The second ultrasonic transmitter / receiver 12 receives (receives) ultrasonic waves transmitted from the first ultrasonic transmitter / receiver 11. The first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12 are arranged upstream and downstream at both ends of the shorter side of the flow channel 101 so that the ultrasonic signals cross the flow of the mixed gas. The first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12 are arranged upstream and downstream on opposing sides of the flow path 101 in the short direction so that ultrasonic signals cross the flow of the mixed gas. Specifically, the first ultrasonic transmitter / receiver 11 is arranged upstream and the second ultrasonic transmitter / receiver 12 is arranged downstream so as to face each other (see FIGS. 2 and 3). An ultrasonic propagation path 106 that propagates ultrasonic waves is formed in the opposing direction between the first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12 (see FIG. 3). The ultrasonic propagation path 106 is inclined at an angle θ with respect to the flow path 101 (see FIG. 3).

[0021] The temperature sensor 13 is, for example, a thermocouple. The temperature sensor 13 is disposed in the flow path 101 and measures the temperature of the mixed gas flowing through the flow path 101.

[0022] (2.2) Processing Device As shown in FIG. 1 , the processing device 20 includes a first communication unit 21 , a second communication unit 22 , a third communication unit 23 , a storage unit 24 , and a control unit 25 .

[0023] The processing device 20 includes, for example, a computer system having one or more processors and a memory. The processor executes a program stored in the memory, causing the computer system to function as the control unit 25. The program executed by the processor is pre-recorded in the memory of the computer system here, but may also be provided by being recorded on a non-transitory recording medium such as a memory card, or via a telecommunications line such as the Internet.

[0024] The first communication unit 21 is a communication interface for communicating with the first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12. The second communication unit 22 is a communication interface for communicating with the temperature sensor 13. The third communication unit 23 is a communication interface for communicating with a user device (not shown) or the like. The user device has a display unit such as a liquid crystal display, and is a device for notifying a user of measurement results and the like in the physical quantity measurement system 1.

[0025] The storage unit 24 is configured by a device selected from a read-only memory (ROM), a random access memory (RAM), an electrically erasable programmable read-only memory (EEPROM), etc. The storage unit 24 stores information used for measuring physical quantities.

[0026] As shown in FIG. 1 , the control unit 25 has a first signal processing unit 201, a second signal processing unit 202, a first acquisition unit 203, a second acquisition unit 204, a third acquisition unit 205, a concentration measurement unit 206, and a flow rate measurement unit 207.

[0027] The first signal processing unit 201 performs processing related to communication between the first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12 .

[0028] For example, when transmitting ultrasonic waves from the first ultrasonic transmitter / receiver 11 to the second ultrasonic transmitter / receiver 12, the first signal processing unit 201 outputs a signal instructing the first ultrasonic transmitter / receiver 11 to transmit ultrasonic waves to the first ultrasonic transmitter / receiver 11 via the first communication unit 21. When transmitting ultrasonic waves from the second ultrasonic transmitter / receiver 12 to the first ultrasonic transmitter / receiver 11, the first signal processing unit 201 outputs a signal instructing the second ultrasonic transmitter / receiver 12 to transmit ultrasonic waves to the second ultrasonic transmitter / receiver 12 via the first communication unit 21.

[0029] The first signal processing unit 201 also calculates the propagation time t ｕｐ (first direction propagation time t ｕｐ Specifically, the first signal processing unit 201 measures the first direction propagation time t ｕｐ Measure.

[0030] The first signal processing unit 201 also calculates the propagation time t ｄｗ (Second direction propagation time t ｄｗ Specifically, the first signal processing unit 201 measures the second direction propagation time t ｄｗ The first signal processing unit 201 measures the first direction propagation time t ｕｐ and the second direction propagation time t ｄｗ The average value of the ultrasonic wave propagation time t ａ It is calculated as follows.

[0031] The second signal processing unit 202 receives the signal output from the temperature sensor 13 and performs predetermined processing on the received signal. For example, when the second signal processing unit 202 receives the signal output from the temperature sensor 13, the second signal processing unit 202 performs predetermined signal processing on the received signal to output the temperature T measured by the temperature sensor 13 as ａ Here, the second signal processing unit 202 calculates the propagation time tａ The timing at which the propagation time t ａ The temperature T ａ That is, the temperature T ａ is the propagation time t ａ is the temperature measured when the temperature is calculated.

[0032] The first acquisition unit 203 acquires the propagation time t of the ultrasonic wave calculated by the first signal processing unit 201. ａ , the temperature T measured by the temperature sensor 13 ａ and reference temperature T ０ Based on this, the reference temperature T ０ The measured propagation time t converted into the propagation time according to ｘ For example, the first acquisition unit 203 acquires the reference temperature T ０ to 20, and "T" to "T ａ " respectively, the propagation time t ａ , the reference temperature T ０ The measured propagation time t ｘ It can be converted to.

[0033]

[0034] The second acquisition unit 204 acquires the propagation time t of the ultrasonic wave when at least the first gas is flowing through the flow channel 101 and the second gas is not flowing. １ (Hereinafter, in the first embodiment, the "first reference propagation time t １ ") is obtained.

[0035] In the first embodiment, the second acquisition unit 204 acquires a first reference propagation time t １ For example, the storage unit 24 stores, as information used to measure the physical quantity, a first reference propagation time t １ The second acquisition unit 204 stores the first reference propagation time t １ is acquired from the storage unit 24. Here, the first reference propagation time t １is information about the first gas, the gas constant R, the distance L between the pair of ultrasonic transducers 11 and 12, and the reference temperature T ０ In the first embodiment, the information about the first gas is a first molecular weight M １ , and the specific heat ratio of the first gas. The information about the first gas includes the first constant pressure molar specific heat c of the first gas as the specific heat ratio of the first gas. ｐ１ , and the first constant volume molar specific heat c of the first gas ｖ１ Includes.

[0036] More specifically, the first reference propagation time t １ is the first molecular weight M １ , first constant pressure molar specific heat c ｐ１ , first constant volume molar specific heat c ｖ１ , gas constant R, reference temperature T ０ and the distance L between the pair of ultrasonic transducers 11 and 12 (see FIG. 3), and the following equation 2:

[0037]

[0038] Here, "c" in the formula 2 is the sound velocity, and "t" is the propagation time of the ultrasonic wave. "γ" is the specific heat ratio, and "γ = c ｐ / c ｖ " relation holds. Here, "c ｐ " is the constant pressure molar specific heat, and "c ｖ " is the molar specific heat at constant volume. "M" in the formula 2 is the molecular weight. Using the relation between the middle and right sides of the formula 2, "γ" in the formula can be changed to "c ｐ１ / c ｖ１ " and "M" to "M １ " to "T" ０ " and solving for "t" gives the first reference propagation time t １ is calculated.

[0039] The third acquisition unit 205 acquires the propagation time t of the ultrasonic wave when at least the second gas is flowing through the flow channel 101 and the first gas is not flowing. ２ (Hereinafter, in the first embodiment, the "second reference propagation time t ２In the first embodiment, the third acquisition unit 205 acquires a second reference propagation time t ２ For example, the storage unit 24 stores, as information used to measure the physical quantity, a second reference propagation time t ２ The third acquisition unit 205 stores the second reference propagation time t ２ is acquired from the storage unit 24. Here, the second reference propagation time t ２ is information about the second gas, the gas constant R, the distance L between the pair of ultrasonic transducers 11 and 12, and the reference temperature T ０ In the first embodiment, the information about the second gas is a second molecular weight M ２ , and the specific heat ratio of the second gas. The information about the second gas includes the second constant pressure molar specific heat c of the second gas as the specific heat ratio of the second gas. ｐ２ , and the second constant-volume molar specific heat c of the second gas ｖ２ Includes.

[0040] More specifically, the second reference propagation time t ２ is the second molecular weight M ２ , second constant pressure molar specific heat c ｐ２ , second constant volume molar specific heat c ｖ２ , gas constant R, reference temperature T ０ and the distance L between the pair of ultrasonic transducers 11 and 12, and the above-mentioned equation 2. Using the relational expression between the middle and right sides of equation 2, "γ" in the equation is changed to "c ｐ２ / c ｖ２ " and "M" to "M ２ " to "T" ０ " and solving for "t" gives the second reference propagation time t ２ is calculated.

[0041] The concentration measurement unit 206 measures the propagation time t ｘ , the first reference propagation time t １ and the second reference propagation time t ２ Here, based on the relational expression of Expression 2 above, the following Expression 3 is obtained.

[0042]

[0043] In the formula 3, "γ １ " is the specific heat ratio of the first gas, and "γ ２ " is the specific heat ratio of the second gas. ｘ " is the molecular weight of the gas mixture. ｘ " is the specific heat ratio of the mixed gas. "T" is temperature. The specific heat ratios of gases with similar molecular structures are approximately equal. In the first embodiment, the first gas is hydrogen and the second gas is nitrogen, so the first gas and the second gas are diatomic molecules. That is, the first gas and the second gas are gases with similar molecular structures. Therefore, the specific heat ratio "γ" of the first gas is １ ", the specific heat ratio of the second gas "γ ２ " and the specific heat ratio of the gas mixture "γ ｘ " can be considered to be equal. Therefore, the following equation 4 can be obtained from equation 3.

[0044]

[0045] The mixed gas contains a first gas (hydrogen) and a second gas (nitrogen). When the concentration of the first gas is x, the following equation 5 holds:

[0046]

[0047] From Equations 4 and 5, the following Equation 6 is obtained.

[0048]

[0049] That is, the concentration measurement unit 206 calculates the second reference propagation time t ２ The measured propagation time t ｘ The first difference value obtained by subtracting the squared value of ２ The first reference propagation time t １ The concentration of the first gas is calculated by dividing the calculated value by a second difference value obtained by subtracting the square of the calculated value.

[0050] The flow rate measuring unit 207 measures the flow rate of the mixed gas in the flow path 101. The flow rate measuring unit 207 obtains the flow rate Q of the mixed gas using the following equation 7. The flow rate Q is calculated by multiplying the cross-sectional area S of the flow path 101 by the flow velocity V. In addition, the flow velocity V, the length L of the ultrasonic propagation path 106 (the distance between the first ultrasonic transducer 11 and the second ultrasonic transducer 12), and the first direction propagation time t ｕｐ , second direction propagation time t ｄｗ From the relationship with the angle θ of the ultrasonic propagation path 106 with respect to the flow path 101, "Q=SV" can be transformed into the right side of Equation 7.

[0051]

[0052] The flow rate measurement unit 207 stores, as information used for measuring the physical quantity, the distance L between the first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12, the angle θ of the ultrasonic propagation path 106 with respect to the flow path 101, the cross-sectional area S, and the first direction propagation time t calculated by the first signal processing unit 201, which are stored in advance in the storage unit 24. ｕｐ and the second direction propagation time t ｄｗ and the above-mentioned equation 7, the flow rate Q of the mixed gas is calculated.

[0053] The flow rate measurement unit 207 may calculate a converted flow rate converted from the calculated flow rate Q to 0° C. and 1 atm.

[0054] (3) Operation Here, the operation of the physical quantity measuring system 1 will be described with reference to FIG.

[0055] The first signal processing unit 201 performs a first measurement process (step S1). Specifically, the first signal processing unit 201 measures a first direction propagation time t ｕｐ The first signal processing unit 201 also measures the second direction propagation time t ｄｗ Furthermore, the first signal processing unit 201 measures the first direction propagation time t ｕｐ and the second direction propagation time t ｄｗ The average value of the ultrasonic wave propagation time t ａ It is calculated as follows.

[0056] The second signal processing unit 202 performs a second measurement process (step S2). Specifically, the second signal processing unit 202 calculates the temperature T measured by the temperature sensor 13 based on the signal output from the temperature sensor 13. ａ Ask for.

[0057] The physical quantity measuring system 1 performs an acquisition process (step S3). The first acquisition unit 203 acquires the propagation time t ａ Measure the propagation time t ｘ By converting it into the reference temperature T ０ Measurement propagation time t according to ｘ For example, the first obtaining unit 203 obtains the propagation time t ａ is the measured propagation time t ｘ The measured propagation time t ｘ The second acquisition unit 204 acquires a first reference propagation time t of an ultrasonic wave when the first gas flows through the flow channel 101 and the second gas does not flow, which is stored in advance in the storage unit 24. １ The third acquisition unit 205 acquires the propagation time t of the ultrasonic wave when the second gas flows through the flow channel 101 and the first gas does not flow, which is stored in advance in the storage unit 24. ２ Here, the first reference propagation time t １ and the second reference propagation time t ２ is the propagation time depending on the reference temperature.

[0058] The concentration measurement unit 206 performs a concentration measurement process (step S4). ｘ , the first reference propagation time t １ and the second reference propagation time t ２ More specifically, the concentration measurement unit 206 measures the concentration x of the first gas using the second reference propagation time t ２ The measured propagation time t ｘ The first difference value obtained by subtracting the squared value of ２ The first reference propagation time t １ The concentration of the first gas is calculated by dividing the calculated value by a second difference value obtained by subtracting the square of the calculated value.

[0059] The flow rate measurement unit 207 performs a flow rate measurement process (step S5). The flow rate measurement unit 207 measures the flow rate of the mixed gas in the flow path 101. More specifically, the flow rate measurement unit 207 calculates the flow rate Q of the mixed gas using Equation 7.

[0060] (4) Advantages As described above, the physical quantity measuring system 1 of the first embodiment includes the flow path 101, the pair of ultrasonic transmitters / receivers 11 and 12, the temperature sensor 13, the first acquisition unit 203, the second acquisition unit 204, the third acquisition unit 205, and the concentration measurement unit 206. A mixed gas containing a first gas and a second gas flows through the flow path 101. The pair of ultrasonic transmitters / receivers 11 and 12 transmit and receive ultrasonic waves and are arranged so that the ultrasonic waves cross the flow of the mixed gas in the flow path 101. The temperature sensor 13 measures the temperature of the mixed gas. The first acquisition unit 203 acquires a measured propagation time corresponding to the reference temperature based on the propagation time of the ultrasonic waves obtained by transmitting and receiving the ultrasonic waves between the pair of ultrasonic transmitters / receivers 11 and 12, the temperature measured by the temperature sensor 13, and the reference temperature. The second acquisition unit 204 acquires a first reference propagation time of the ultrasonic wave when at least the first gas is flowing and the second gas is not flowing through the flow path 101. The third acquisition unit 205 acquires a second reference propagation time of the ultrasonic wave when at least the second gas is flowing and the first gas is not flowing through the flow path 101. The concentration measurement unit 206 measures the concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time.

[0061] According to this configuration, the concentration of the first gas is measured using the measured propagation time, the first reference propagation time, and the second reference propagation time, so that the concentration of the gas contained in the mixed gas can be measured using a measurement method different from conventional measurement methods.

[0062] (5) Modifications Modifications are listed below. The modifications described below can be applied in appropriate combination with the first embodiment.

[0063] (5.1) Modification 1 In the first embodiment, the second obtaining unit 204 obtains the first molecular weight M １ , first constant pressure molar specific heat c ｐ１ , first constant volume molar specific heat c ｖ１ , gas constant R, reference temperature T ０and the first reference propagation time t calculated using the distance L between the pair of ultrasonic transmitters and receivers 11 and 12. １ However, the present invention is not limited to this configuration. The processing device 20 acquires a first propagation time t １１ may be stored in advance. At this time, the first propagation time t １１ The temperature T measured by the temperature sensor 13 when ａ (Hereinafter, "first temperature T ａ１ For example, the processing device 20 stores the first propagation time t １１ is measured, and the measurement result, the first propagation time t １１ The processing device 20 stores the first propagation time t １１ The first temperature T measured by the temperature sensor 13 when ａ１ The physical quantity measuring system 1 also stores the first propagation time t １１ and first temperature T ａ１ Based on this, the reference temperature T ０ The first reference propagation time t １ By calculating the first reference propagation time t １ For example, the second obtaining unit 204 obtains "ta" in the above-mentioned equation 1 by １１ " to "T" ａ１ ” respectively, the first propagation time t １１ , the reference temperature T ０ The first reference propagation time t １ can be converted into

[0064] The third obtaining unit 205 obtains the second molecular weight M ２ , second constant pressure molar specific heat c ｐ２ , second constant volume molar specific heat c ｖ２ , the gas constant R, and the distance L between the pair of ultrasonic transducers 11 and 12. ２However, the present invention is not limited to this configuration. The processing device 20 acquires a second propagation time t ２１ In this case, the second propagation time t ２１ The temperature T measured by the temperature sensor 13 when ａ (Hereinafter, "second temperature T ａ２ For example, the processing device 20 stores the second propagation time t ２１ is measured, and the measurement result, the second propagation time t ２１ The processing device 20 stores the second propagation time t ２１ The second temperature T measured by the temperature sensor 13 when ａ２ The physical quantity measuring system 1 also stores the second propagation time t ２１ and second temperature T ａ２ Based on this, the reference temperature T ０ The second reference propagation time t ２ By calculating the second reference propagation time t ２ For example, the third obtaining unit 205 obtains "ta" in the above-mentioned equation 1 by ２１ " to "T" ａ２ ” respectively, the second propagation time t ２１ , the reference temperature T ０ The second reference propagation time t ２ can be converted into

[0065] That is, the processing device 20 calculates the first propagation time t １１ and the second propagation time t ２１ In other words, the processing device 20 may store at least one of the first propagation time t １１ and the first temperature T ａ１ and the second propagation time t ２１ and the second temperature T ａ２ At least one of the sets of and may be stored in advance.

[0066] Alternatively, the processing device 20 may use the first propagation time t １１ , first temperature T ａ１ , and reference temperature T ０ The first reference propagation time t calculated from １ , and the second propagation time t measured at the time of manufacturing the processing device 20 or at the time of shipping the processing device 20. ２１ , second temperature T ａ２ , and reference temperature T ０ The second reference propagation time t calculated from ２ At least one of these may be stored in advance.

[0067] (5.2) Modification 2 The second acquisition unit 204 acquires the first molecular weight M １ , first constant pressure molar specific heat c ｐ１ , first constant volume molar specific heat c ｖ１ , gas constant R, temperature T measured by the temperature sensor 13 ａ The propagation time (hereinafter referred to as a first tentative propagation time in the second modification) may be calculated using the temperature T measured by the temperature sensor 13 and the distance L between the pair of ultrasonic transmitters and receivers 11 and 12. ａ , reference temperature T ０ The first tentative propagation time calculated using the above-mentioned Equation 1 is converted into the first reference propagation time t １ By converting it into the first reference propagation time t １ may be obtained.

[0068] Similarly, the third acquisition unit 205 acquires the second molecular weight M ２ , second constant pressure molar specific heat c ｐ２ , second constant volume molar specific heat c ｖ２ , gas constant R, temperature T measured by the temperature sensor 13 ａ The propagation time (hereinafter referred to as the second provisional propagation time in the second modification) may be calculated using the temperature T measured by the temperature sensor 13. ａ , reference temperature T ０ The second tentative propagation time calculated using the above-mentioned Equation 1 is converted into the second reference propagation time t ２ By converting it into the second reference propagation time t２ may be obtained.

[0069] Alternatively, the second acquisition unit 204 acquires the first molecular weight M １ , first constant pressure molar specific heat c ｐ１ , first constant volume molar specific heat c ｖ１ , gas constant R, distance L between the pair of ultrasonic transducers 11 and 12, and reference temperature T ０ Using the first reference propagation time t １ may be calculated (obtained).

[0070] Similarly, the third acquisition unit 205 acquires the second molecular weight M ２ , second constant pressure molar specific heat c ｐ２ , second constant volume molar specific heat c ｖ２ , gas constant R, distance L between the pair of ultrasonic transducers 11 and 12, and reference temperature T ０ Using the second reference propagation time t ２ may be calculated (obtained).

[0071] (5.3) Modification 3 The flow path main body 10 may further include one or more partition plates. The one or more partition plates divide the flow path 101 into multiple sections in the height direction (Z direction) of the flow path 101. By dividing the flow path 101 into multiple sections with the one or more partition plates, a multi-layer flow path is formed in the flow path 101. This configuration increases the aspect ratio of the flow path cross section of each layer of the multi-layer flow path, making the flow two-dimensional, and rectifying the flow and stabilizing turbulence.

[0072] (5.4) Modification 4 The flow path main body 10 may have a plurality of temperature sensors 13. That is, the physical quantity measuring system 1 may be provided with a plurality of temperature sensors 13. When the flow path main body 10 has a plurality of temperature sensors 13, the second signal processing unit 202 calculates the average value of the temperatures measured by the plurality of temperature sensors 13 as the temperature T of the mixed gas. ａ It is calculated as follows.

[0073] (5.5) Variation 5 The first ultrasonic transmitter / receiver 11 is arranged upstream and the second ultrasonic transmitter / receiver 12 is arranged downstream, facing each other, i.e., the arrangement direction of the first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12 intersects with the X direction, but this configuration is not limited to this.

[0074] The first ultrasonic transmitter / receiver 11 and the second ultrasonic transmitter / receiver 12 may be arranged along the X direction, but not intersect with the X direction.

[0075] In this case, the ultrasonic waves output from the first ultrasonic transmitter / receiver 11 are reflected within the flow path 101, and the reflected ultrasonic waves are input to the second ultrasonic transmitter / receiver 12. Furthermore, the ultrasonic waves output from the second ultrasonic transmitter / receiver 12 are reflected within the flow path 101, and the reflected ultrasonic waves are input to the first ultrasonic transmitter / receiver 11. That is, the path of the ultrasonic waves is V-shaped and crosses the flow of the mixed gas in the flow path 101. That is, in the fourth modification as well, the pair of ultrasonic transmitters / receivers 11, 12 are arranged so that the ultrasonic waves cross the flow of the mixed gas in the flow path 101.

[0076] (Embodiment 2) A physical quantity measuring system 1A according to embodiment 2 will be described with reference to Figures 5 to 7. The physical quantity measuring system 1A according to embodiment 2 differs from the physical quantity measuring system 1 according to embodiment 1 in that the physical quantity measuring system 1A according to embodiment 2 measures the concentration of a first gas when a mixed gas contains water vapor in addition to a first gas and a second gas. The following description will focus on the differences. Note that the same components as those in embodiment 1 are denoted by the same reference numerals, and their description will be omitted.

[0077] (1) Configuration The detailed configuration of the physical quantity measuring system 1A will be described with reference to FIGS. 5 and 6. FIG.

[0078] As shown in FIG. 5 , the physical quantity measurement system 1A includes a flow path main body 10A and a processing device 20A. The physical quantity measurement system 1A measures the concentration of hydrogen (hydrogen concentration) contained in a mixed gas flowing through the flow path main body 10A, the flow rate of the mixed gas, the water vapor pressure of water vapor contained in the mixed gas, and the concentration of water vapor (water vapor concentration) as physical quantities. Here, the concentration measured by the physical quantity measurement system 1A is, for example, volume concentration. FIG. 6 is a cross-sectional view of the flow path main body 10A in the X-Y plane defined in the first embodiment. Note that FIG. 6 does not depict the pair of ultrasonic transmitter / receivers 11 and 12 and the temperature sensor 13. Furthermore, FIG. 6 also schematically illustrates the pressure sensor 14 and the humidity sensor 15.

[0079] (1.1) Flow Channel Main Body A mixed gas flows through the flow channel main body 10A. As shown in Fig. 5, the flow channel main body 10A has a pair of ultrasonic transmitters / receivers 11, 12, a temperature sensor 13, a pressure sensor 14, and a humidity sensor 15. Furthermore, as shown in Fig. 6, the flow channel main body 10A further has a main body portion 100. In the following description, the ultrasonic transmitter / receiver 11 may be referred to as the first ultrasonic transmitter / receiver 11, and the ultrasonic transmitter / receiver 12 may be referred to as the second ultrasonic transmitter / receiver 12.

[0080] The pressure sensor 14 measures the pressure of the mixed gas flowing through the flow path 101. The humidity sensor 15 is disposed downstream of the flow path 101, for example.

[0081] The humidity sensor 15 measures the humidity of the mixed gas. The humidity sensor 15 is disposed, for example, downstream of the flow path 101.

[0082] (1.2) Processing Device As shown in FIG. 5, the processing device 20A includes a first communication unit 21, a second communication unit 22, a third communication unit 23, a storage unit 24, and a control unit 25A.

[0083] The processing device 20A includes, for example, a computer system having one or more processors and a memory. The processor executes a program stored in the memory, causing the computer system to function as the control unit 25A. The program executed by the processor is pre-recorded in the memory of the computer system here, but may also be provided by being recorded on a non-transitory recording medium such as a memory card, or via a telecommunications line such as the Internet.

[0084] As shown in FIG. 5, the control unit 25A has a first signal processing unit 201, a second signal processing unit 202A, a first acquisition unit 203, a second acquisition unit 204A, a third acquisition unit 205A, a concentration measurement unit 206A, a flow rate measurement unit 207, a water vapor pressure measurement unit 208, and a water vapor concentration measurement unit 209.

[0085] The second signal processing unit 202A receives the signal output from the temperature sensor 13 and performs predetermined processing on the received signal. For example, when the second signal processing unit 202 receives the signal output from the temperature sensor 13, the second signal processing unit 202 performs predetermined signal processing on the received signal to output the temperature T ａ Ask for.

[0086] Furthermore, when the second signal processing unit 202A receives the signal output from the pressure sensor 14, it performs predetermined signal processing on the received signal to determine the pressure measured by the pressure sensor 14.

[0087] When the second signal processing unit 202A receives the signal output from the humidity sensor 15, it performs predetermined signal processing on the received signal to determine the humidity measured by the humidity sensor 15.

[0088] The water vapor pressure measuring unit 208 measures the water vapor pressure of water vapor contained in the mixed gas flowing through the flow path 101. The water vapor pressure measuring unit 208 measures the water vapor pressure of water vapor based on the humidity of the mixed gas measured by the humidity sensor 15 and the temperature of the mixed gas measured by the temperature sensor 13.

[0089] The water vapor concentration measurement unit 209 measures the concentration of water vapor contained in the mixed gas. Here, the water vapor concentration measurement unit 209 measures the water vapor concentration, which is the concentration of water vapor contained in the mixed gas, based on the water vapor pressure measured by the water vapor pressure measurement unit 208 and the pressure of the mixed gas measured by the pressure sensor 14. That is, the water vapor concentration measurement unit 209 measures the water vapor concentration using the pressure of the mixed gas measured by the pressure sensor 14, the humidity measured by the humidity sensor 15, and the temperature measured by the temperature sensor 13.

[0090] The first acquisition unit 203 acquires the propagation time t of the ultrasonic wave calculated by the first signal processing unit 201. ａ , the temperature T measured by the temperature sensor 13 ａ and reference temperature T ０ Based on this, the reference temperature T ０ The measured propagation time t converted into the propagation time according to ｘ Get.

[0091] The second acquisition unit 204A acquires first gas information related to the first gas, water vapor information related to water vapor, a gas constant R, a distance L between the pair of ultrasonic transducers, and a reference temperature T ０ , and the water vapor concentration measured by the water vapor concentration measuring unit 209, the ultrasonic wave propagation time t ｗ１ (Hereinafter, in the second embodiment, the "first reference propagation time t ｗ１ ") to obtain the first reference propagation time t ｗ１ In the second embodiment, the first gas information is a first molecular weight M １ , and the specific heat ratio of the first gas (first specific heat ratio). The first gas information includes the first constant pressure molar specific heat c ｐ１ , and the first constant volume molar specific heat c of the first gas ｖ１ The water vapor information includes the molecular weight of water vapor, M ｗ The water vapor information includes the specific heat ratio of water vapor (third specific heat ratio), and the constant pressure molar specific heat of water vapor c ｐｗ , and the constant volume molar specific heat of water vapor c ｖｗ Includes.

[0092] When the mixed gas contains the first gas (hydrogen) and water vapor, the following equations 8 to 10 are established. Here, the molecular weight of the mixed gas containing the first gas and water vapor is defined as M ｈｗ , water vapor concentration x ｗ Let's say.

[0093]

[0094]

[0095]

[0096] Furthermore, from Equation 2 and Equations 8 to 10, the first reference propagation time t ｗ１ The following equation 11 is obtained for

[0097]

[0098] Here, the storage unit 24 stores information used to measure physical quantities, such as first gas information, second gas information, water vapor information, a gas constant R, and a reference temperature T ０ , the distance L between the pair of ultrasonic transmitters and receivers 11 and 12 is stored.

[0099] The second acquisition unit 204A acquires the first gas information, the water vapor information, the gas constant R, the reference temperature T ０ , the distance L between the pair of ultrasonic transmitters and receivers 11 and 12, and the above-mentioned equation 11, the first reference propagation time t of the ultrasonic wave when the first gas and water vapor flow through the flow path 101 and the second gas does not flow is calculated. ｗ１ By calculating the first reference propagation time t ｗ１ Get.

[0100] The third acquisition unit 205A acquires second gas information related to the second gas, water vapor information related to water vapor, a gas constant R, a distance L between the pair of ultrasonic transmitter-receivers, and a reference temperature T ０ , and the water vapor concentration measured by the water vapor concentration measuring unit 209, the ultrasonic wave propagation time t ｗ２ (Hereinafter, in the second embodiment, the "second reference propagation time t ｗ２ ") to obtain the second reference propagation time t ｗ２ In the second embodiment, the second gas information is a second molecular weight M２ , and the specific heat ratio of the second gas (second specific heat ratio). The second gas information includes the second constant pressure molar specific heat c ｐ２ , and the second constant-volume molar specific heat c of the second gas ｖ２ Includes.

[0101] When the mixed gas contains a second gas (nitrogen) and water vapor, the same formulas as Formulas 8 to 10 are established. For example, the molecular weight of the mixed gas containing the second gas and water vapor is M ｎｗ The second molecular weight of the second gas (nitrogen) is M ２ , the second constant pressure molar specific heat is c ｐ２ , the second constant volume molar specific heat is c ｖ２ The molecular weight of water vapor is M ｗ , constant pressure molar specific heat is c ｐｗ , constant volume molar specific heat is c ｖｗ , water vapor concentration x ｗ Let's say. ｈｗ M ｎｗ To M １ M ２ To, c ｐ１ A ｐ２ To, c ｖ１ A ｖ２ By substituting these, the same formulas as Formulas 8 to 11 can be obtained.

[0102] The third acquisition unit 205A acquires the second gas information, the water vapor information, the gas constant R, the reference temperature T ０ , the distance L between the pair of ultrasonic transmitters and receivers 11 and 12, and the above-mentioned equation 11, the second reference propagation time t of the ultrasonic wave when the second gas and water vapor flow through the flow path 101 and the first gas does not flow is calculated. ｗ２ By calculating the second reference propagation time t ｗ２ Get.

[0103] The concentration measurement unit 206A measures the propagation time t ｘ , the first reference propagation time t ｗ１ and the second reference propagation time t ｗ２ Specifically, the concentration measurement unit 206A measures the concentration x of the first gas using t １ t ｗ１ To, t ２ t ｗ２The concentration x of the first gas is measured using the following equation 12 in which

[0104]

[0105] That is, the concentration measurement unit 206A calculates the second reference propagation time t ｗ２ The measured propagation time t ｘ The first difference value obtained by subtracting the squared value of ｗ２ The first reference propagation time t ｗ１ The concentration of the first gas is calculated by dividing the calculated value by a second difference value obtained by subtracting the square of the calculated value.

[0106] (2) Operation Here, the operation of the physical quantity measuring system 1A will be described with reference to FIG.

[0107] The first signal processing unit 201 performs a first measurement process (step S101). Specifically, the first signal processing unit 201 measures a first direction propagation time t ｕｐ The first signal processing unit 201 also measures the second direction propagation time t ｄｗ Furthermore, the first signal processing unit 201 measures the first direction propagation time t ｕｐ and the second direction propagation time t ｄｗ The average value of the ultrasonic wave propagation time t ａ It is calculated as follows.

[0108] The second signal processing unit 202A performs a second measurement process (step S102). Specifically, the second signal processing unit 202A calculates the temperature T measured by the temperature sensor 13 based on the signal output from the temperature sensor 13. ａ The second signal processing unit 202A calculates the pressure measured by the pressure sensor 14 based on the signal output from the pressure sensor 14. Furthermore, the second signal processing unit 202A calculates the humidity measured by the humidity sensor 15 based on the signal output from the humidity sensor 15.

[0109] The physical quantity measurement system 1A performs a water vapor concentration measurement process (step S103). The water vapor pressure measurement unit 208 measures the water vapor pressure of water vapor based on the humidity of the mixed gas measured by the humidity sensor 15 and the temperature of the mixed gas measured by the temperature sensor 13. The water vapor concentration measurement unit 209 measures the water vapor concentration, which is the concentration of water vapor contained in the mixed gas, based on the water vapor pressure measured by the water vapor pressure measurement unit 208 and the pressure of the mixed gas measured by the pressure sensor 14.

[0110] The physical quantity measuring system 1A performs an acquisition process (step S104). The first acquisition unit 203 acquires the propagation time t ａ Measure the propagation time t ｘ For example, the first acquisition unit 203 converts the propagation time t ａ , the reference temperature T ０ The measured propagation time t ｘ The second acquisition unit 204A converts the first gas information, the water vapor information, the gas constant R, the reference temperature T ０ , the distance L between the pair of ultrasonic transmitters and receivers 11 and 12, and the above-mentioned equation 11, the first reference propagation time t of the ultrasonic wave when the first gas and water vapor flow through the flow path 101 and the second gas does not flow is calculated. ｗ１ By calculating the first reference propagation time t ｗ１ The third acquisition unit 205A acquires the second gas information, the water vapor information, the gas constant R, the reference temperature T ０ , the distance L between the pair of ultrasonic transmitters and receivers 11 and 12, and the above-mentioned equation 11, the second reference propagation time t of the ultrasonic wave when the second gas and water vapor flow through the flow path 101 and the first gas does not flow is calculated. ｗ２ By calculating the second reference propagation time t ｗ２ Get.

[0111] The concentration measurement unit 206A performs a concentration measurement process (step S105). ｘ , the first reference propagation time t ｗ１ and the second reference propagation time t ｗ２ More specifically, the concentration measurement unit 206A measures the concentration x of the first gas using the second reference propagation time t ｗ２The measured propagation time t ｘ The first difference value obtained by subtracting the squared value of ｗ２ The first reference propagation time t ｗ１ The concentration of the first gas is calculated by dividing the calculated value by a second difference value obtained by subtracting the square of the calculated value.

[0112] The flow rate measurement unit 207 performs a flow rate measurement process (step S106). The flow rate measurement unit 207 measures the flow rate of the mixed gas in the flow path 101. More specifically, the flow rate measurement unit 207 calculates the flow rate Q of the mixed gas using Equation 7.

[0113] The physical quantity measuring system 1A executes steps S101 to S106, which are the operations shown in FIG. 7, every time the concentration of the first gas is measured.

[0114] (3) Advantages The physical quantity measuring system 1A of embodiment 2 includes a flow path 101, a pair of ultrasonic transmitter / receivers 11 and 12, a temperature sensor 13, a pressure sensor 14, a humidity sensor 15, a water vapor concentration measuring unit 209, a first acquisition unit 203, a second acquisition unit 204A, a third acquisition unit 205A, and a concentration measuring unit 206A. A mixed gas containing a first gas and a second gas flows through the flow path 101. The pair of ultrasonic transmitter / receivers 11 and 12 transmit and receive ultrasonic waves and are arranged so that the ultrasonic waves intersect the flow of the mixed gas in the flow path 101. The temperature sensor 13 measures the temperature of the mixed gas. The pressure sensor 14 measures the pressure of the mixed gas. The humidity sensor 15 measures the humidity of the mixed gas. The first acquisition unit 203 acquires a measured propagation time corresponding to a reference temperature based on the propagation time of ultrasound obtained by transmission and reception of ultrasound between the pair of ultrasonic transmitters and receivers 11, 12, the temperature measured by the temperature sensor 13, and a reference temperature. The second acquisition unit 204A acquires a first reference propagation time of ultrasound when at least a first gas flows through the flow path 101 and a second gas does not. The third acquisition unit 205A acquires a second reference propagation time of ultrasound when at least a second gas flows through the flow path 101 and the first gas does not flow. The concentration measurement unit 206A measures the concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time. The water vapor concentration measurement unit 209 measures the water vapor concentration using the pressure of the mixed gas measured by the pressure sensor 14, the humidity measured by the humidity sensor 15, and the temperature measured by the temperature sensor 13. The second acquisition unit 204A acquires the first reference propagation time by calculating a first reference propagation time when the first gas and water vapor flow through the flow path 101 and the second gas does not flow, based on first gas information about the first gas, water vapor information about the water vapor, a gas constant, the distance between the pair of ultrasonic transmitter / receivers 11 and 12, the reference temperature, and the water vapor concentration measured by the water vapor concentration measurement unit 209. The third acquisition unit 205A acquires the second reference propagation time by calculating a second reference propagation time when the second gas and water vapor flow through the flow path 101 and the first gas does not flow, based on second gas information about the second gas, the water vapor information, a gas constant, the distance between the pair of ultrasonic transmitter / receivers, the reference temperature, and the water vapor concentration measured by the water vapor concentration measurement unit 209.

[0115] According to this configuration, the concentration of the first gas is measured using the measured propagation time, the first reference propagation time, and the second reference propagation time, so that the concentration of the gas contained in the mixed gas can be measured using a measurement method different from conventional measurement methods.

[0116] Here, in the first embodiment, the mixed gas does not contain water vapor. Furthermore, since both the first gas and the second gas are diatomic molecules, the specific heat ratios of the first gas and the second gas can be considered to be the same. On the other hand, in the second embodiment, the mixed gas contains water vapor, which is a polyatomic molecule, and the first gas and the second gas, which are diatomic molecules. Therefore, the specific heat ratios of the first gas, the second gas, and water vapor cannot be considered to be the same. Therefore, in the second embodiment, when calculating the first reference propagation time and the second reference propagation time, "M" is applied to the first equation expressed by Equation 11 and Equation 11. １ " to "M ２ " to "c ｐ１ " to "c ｐ２ " to "c ｖ１ " to "c ｖ２ " is used. By using the first and second formulas, the first reference propagation time of the first gas and the second reference propagation time of the second gas can be corrected according to the concentration of water vapor.

[0117] (4) Modifications Modifications are listed below. The modifications described below can be applied in appropriate combination with the second embodiment.

[0118] (4.1) Modification 1 The processing device 20A calculates the propagation time t of the ultrasonic wave measured in advance when the first gas flows through the flow path 101 and the second gas does not flow through the flow path 101. １１ (Hereinafter, in Modification 1, the "first propagation time t １１ "), and the propagation time t ２１ (Hereinafter, in Modification 1, the "second propagation time t ２１ At least one of the above may be stored in advance.

[0119] The processing device 20A is configured to calculate the first propagation time t１１ is measured, and the measurement result, the first propagation time t １１ is stored in the storage unit 24. At this time, the first propagation time t １１ The temperature T measured by the temperature sensor 13 when ａ (Hereinafter, "first temperature T ａ１ ") is also stored in advance.

[0120] When the physical quantity measuring system 1A measures the concentration of the first gas, the second acquisition unit 204A of the processing device 20A acquires the first propagation time t １１ , the first propagation time t １１ The first temperature T measured by the temperature sensor 13 when ａ１ and reference temperature T ０ and humidity conversion based on the water vapor concentration measured by the water vapor concentration measurement unit 209, and the first reference propagation time t ｗ１ Get.

[0121] The second acquisition unit 204A acquires the first propagation time t １１ , the first propagation time t １１ The first temperature T measured by the temperature sensor 13 when ａ１ , reference temperature T ０ and temperature conversion is performed using Equation 1, and the first propagation time t １１ The reference temperature T ０ The first temperature conversion time t ｗｔ１ Here, since the mixed gas contains water vapor in addition to the first gas, the first temperature conversion time t ｗｔ１ is calculated by multiplying the propagation time (first reference propagation time t ｗ１ ) needs to be further converted to

[0122] Therefore, the second acquisition unit 204A performs humidity conversion and calculates the first temperature conversion time t ｗｔ１ is the first reference propagation time t ｗ１ Specifically, the second acquisition unit 204 calculates the first temperature conversion time t ｗｔ１ the first reference propagation time t ｗ１ Here, c in the formula 13 is ｄ is the speed of sound when the gas mixture does not contain water vapor. １is the speed of sound when the gas mixture contains water vapor.

[0123] The second acquisition unit 204A acquires the first constant pressure molar specific heat c ｐ１ , first constant volume molar specific heat c ｖ１ , and the first temperature conversion time t calculated using Equation 13 ｗｔ１ is the first reference propagation time t ｗ１ Convert to.

[0124]

[0125] Furthermore, the processing device 20A is configured to calculate the second propagation time t ２１ is measured, and the measurement result, the second propagation time t ２１ is stored in the storage unit 24. At this time, the second propagation time t ２１ The temperature T measured by the temperature sensor 13 when ａ (Hereinafter, "second temperature T ａ２ ") is also stored in advance.

[0126] When the physical quantity measuring system 1A measures the concentration of the first gas, the third acquisition unit 205A of the processing device 20A acquires the second propagation time t ２１ , the second propagation time t ２１ The second temperature T measured by the temperature sensor 13 when ａ２ and reference temperature T ０ and humidity conversion based on the water vapor concentration measured by the water vapor concentration measurement unit 209, and the second propagation time t ２１ is the second reference propagation time t ｗ２ Convert to.

[0127] The third acquisition unit 205A acquires the second propagation time t ２１ , the second propagation time t ２１ The second temperature T measured by the temperature sensor 13 when ａ２ , reference temperature T ０ and temperature conversion is performed using Equation 1, and the second propagation time t ２１ The reference temperature T ０ The second temperature conversion time t ｗｔ２Here, since the mixed gas contains water vapor in addition to the second gas, the second temperature conversion time t ｗｔ２ is calculated by taking into account the propagation time (second reference propagation time t ｗ２ ) needs to be further converted to

[0128] Therefore, the third acquisition unit 205A performs humidity conversion and calculates the second temperature conversion time t ｗｔ２ is the second reference propagation time t ｗ２ When the mixed gas contains the second gas and water vapor, a formula similar to Formula 13 holds. For example, the second constant pressure molar specific heat of the second gas is converted to c ｐ２ , the second constant volume molar specific heat is c ｖ２ In this case, t ｗ１ t ｗ２ To, c ｐ１ A ｐ２ To, c ｖ１ A ｖ２ To M １ M ２ By substituting these, an equation similar to equation 13 can be obtained.

[0129] The third acquisition unit 205A acquires the second constant pressure molar specific heat c ｐ２ , second constant volume molar specific heat c ｖ２ , and the second temperature conversion time t calculated using Equation 13 ｗｔ２ is the second reference propagation time t ｗ２ Convert to.

[0130] Alternatively, the processing device 20A may use the first propagation time t １１ , first temperature T ａ１ , and reference temperature T ０ The first temperature conversion time t ｗｔ１ , and the second propagation time t measured at the time of manufacturing the processing device 20 or at the time of shipping the processing device 20. ２１ , second temperature T ａ２ , and reference temperature T ０ The second temperature conversion time t ｗｔ２ At least one of these may be stored in advance.

[0131] (4.2) Modification 2 In the second embodiment, the mixed gas contains a first gas and a second gas, which are diatomic molecules, and water vapor, which is a polyatomic molecule. However, the mixed gas is not limited to this configuration. The first gas and the second gas contained in the mixed gas may be monoatomic molecules or polyatomic molecules. In this case, the first gas and the second gas may have the same molecular structure or different molecular structures.

[0132] When the first gas and the second gas have different molecular structures, the first reference propagation time t ｗ１ The term in the denominator of the right side of Equation 11 may be constantized by the specific heat ratio. ａ is the average value of the specific heat ratio of the first gas and the specific heat ratio of water vapor.

[0133]

[0134] In addition, the second reference propagation time t ｗ２ The mathematical expression for can be expressed as in Equation 15. Here, γ ｂ is the average value of the specific heat ratio of the second gas and the specific heat ratio of water vapor.

[0135]

[0136] In the second modification, the first gas information includes a first molecular weight of the first gas and a first specific heat ratio of the first gas. The second gas information includes a second molecular weight of the second gas and a second specific heat ratio of the second gas. The water vapor information includes a third molecular weight of the water vapor and a third specific heat ratio of the water vapor. Thus, the second acquisition unit 204A obtains γ , which is an average value of the specific heat ratio of the first gas and the specific heat ratio of the water vapor. ａ and the third acquisition unit 205A acquires γ which is the average value of the specific heat ratio of the second gas and the specific heat ratio of water vapor. ｂ can be calculated respectively.

[0137] (4.3) Modification 3 Every time the second acquisition unit 204A measures the concentration x of the first gas, it acquires the first gas information, the water vapor information, the gas constant R, the distance L between the pair of ultrasonic transducers, and the temperature T measured by the temperature sensor 13. ａ, and the water vapor concentration measured by the water vapor concentration measuring unit 209, the propagation time of the ultrasonic wave (hereinafter referred to as the "first tentative reference propagation time" in the third modification) may be calculated. In this case, the second acquisition unit 204A may calculate the temperature T ａ , reference temperature T ０ The first tentative propagation time calculated using the above-mentioned Equation 1 is converted into the first reference propagation time t ｗ１ By converting it into the first reference propagation time t ｗ１ may be obtained.

[0138] Similarly, every time the third acquisition unit 205A measures the concentration x of the first gas, it acquires the second gas information, the water vapor information, the gas constant R, the distance L between the pair of ultrasonic transducers, and the temperature T measured by the temperature sensor 13. ａ , and the water vapor concentration measured by the water vapor concentration measuring unit 209, the propagation time of the ultrasonic wave (hereinafter referred to as the "second provisional reference propagation time" in the third modification) may be calculated. In this case, the third acquisition unit 205A may calculate the temperature T ａ , reference temperature T ０ The second tentative propagation time calculated using the above-mentioned Equation 1 is converted into the second reference propagation time t ｗ２ By converting it into the second reference propagation time t ｗ２ may be obtained.

[0139] Alternatively, the second acquisition unit 204A may acquire the first gas information, the water vapor information, the gas constant R, the distance L between the pair of ultrasonic transducers, and the reference temperature T every time the concentration x of the first gas is measured. ０ , and the water vapor concentration measured by the water vapor concentration measurement unit 209, the first reference propagation time t ｗ１ may be calculated (obtained).

[0140] Similarly, every time the third acquisition unit 205A measures the concentration x of the first gas, it acquires the second gas information, the water vapor information, the gas constant R, the distance L between the pair of ultrasonic transducers, and the reference temperature T ０ , and the water vapor concentration measured by the water vapor concentration measurement unit 209, the second reference propagation time t ｗ２ may be calculated (obtained).

[0141] (4.4) Modification 4 At least one of Modifications 3, 4, and 5 of the first embodiment may be applied to the second embodiment.

[0142] (Embodiment 3) Embodiment 3 differs from embodiment 2 in that a density sensor is used to measure the water vapor concentration instead of the humidity sensor 15. The configuration of a physical quantity measuring system 1B according to embodiment 3 will be described below, focusing on the differences from the physical quantity measuring system 1A of embodiment 2. Note that the same components as those in the physical quantity measuring system 1A are denoted by the same reference numerals, and their description will be omitted.

[0143] 8, the physical quantity measurement system 1B includes a flow path main body 10B and a processing device 20B. The physical quantity measurement system 1B measures the concentration of hydrogen contained in a mixed gas flowing through the flow path main body 10B (hydrogen concentration), the flow rate of the mixed gas, the water vapor pressure of water vapor contained in the mixed gas, and the concentration of water vapor (water vapor concentration), as physical quantities. Here, the concentrations measured by the physical quantity measurement system 1B are, for example, volume concentrations.

[0144] (1.1) Flow Channel Main Body The mixed gas flows through the flow channel main body 10B. As shown in FIG. 8, the flow channel main body 10B has a pair of ultrasonic transmitters / receivers 11, 12, a temperature sensor 13, a pressure sensor 14, and a density sensor 16. The flow channel main body 10B further has a main body 100 (see FIG. 6). In the following description, the ultrasonic transmitter / receiver 11 may be referred to as the first ultrasonic transmitter / receiver 11, and the ultrasonic transmitter / receiver 12 may be referred to as the second ultrasonic transmitter / receiver 12.

[0145] The density sensor 16 is, for example, a vibration type density meter. The density sensor 16 measures the density of the mixed gas flowing through the flow path 101 (see FIG. 6 ). The density sensor 16 is disposed downstream of the flow path 101, for example.

[0146] (1.2) Processing Device As shown in FIG. 8, the processing device 20B includes a first communication unit 21, a second communication unit 22, a third communication unit 23, a storage unit 24, and a control unit 25B.

[0147] The processing device 20B includes, for example, a computer system having one or more processors and a memory. The processor executes a program stored in the memory, causing the computer system to function as the control unit 25B. The program executed by the processor is pre-recorded in the memory of the computer system in this example, but may also be provided by being recorded on a non-transitory recording medium such as a memory card, or via a telecommunications line such as the Internet.

[0148] As shown in FIG. 8, the control unit 25B has a first signal processing unit 201, a second signal processing unit 202B, a first acquisition unit 203, a second acquisition unit 204B, a third acquisition unit 205B, a concentration measurement unit 206A, a flow rate measurement unit 207, and a water vapor concentration measurement unit 209B.

[0149] The second signal processing unit 202B receives signals output from each sensor and performs predetermined processing on the received signals. When the second signal processing unit 202B receives a signal output from the temperature sensor 13, it performs predetermined signal processing on the received signal to determine the temperature T measured by the temperature sensor 13. When the second signal processing unit 202B receives a signal output from the pressure sensor 14, it performs predetermined signal processing on the received signal to determine the pressure P measured by the pressure sensor 14. When the second signal processing unit 202B receives a signal output from the density sensor 16, it performs predetermined signal processing on the received signal to determine the density ρ measured by the density sensor 16.

[0150] The second signal processing unit 202B converts the calculated density ρ into a standard density ρ using the calculated density ρ, temperature T, pressure P, and the following equation (16). ０ That is, the second signal processing unit 202B converts the density ρ measured by the density sensor 16 into a standard density ρ ０ Here, P ０ is the pressure (reference pressure) when the gas is in its standard state, and T ０ is the temperature (reference temperature) of the gas in the standard state. The second signal processing unit 202B inputs the calculated density ρ, temperature T, and pressure P, and the reference pressure P into the right side of Equation 16. ０and the reference temperature T ０ By substituting and, the density ρ can be converted to the standard density ρ ０ Here, the reference pressure P ０ and reference temperature T ０ is stored in advance in the storage unit 24. The standard state of a gas refers to the state at 20° C. and 1 atm.

[0151]

[0152] The water vapor concentration measurement unit 209B calculates a water vapor concentration x , which is the concentration of water vapor in the mixed gas, using the pressure P of the mixed gas measured by the pressure sensor 14, the density ρ measured by the density sensor 16, and the temperature T measured by the temperature sensor 13. ｗ Here, the water vapor concentration measurement unit 209B calculates the water vapor concentration x using the following equation 17. ｗ That is, the water vapor concentration measurement unit 209B calculates the standard density ρ obtained from the pressure P of the mixed gas measured by the pressure sensor 14, the density ρ measured by the density sensor 16, and the temperature T measured by the temperature sensor 13. ０ Using this, the water vapor concentration x ｗ Here, "ρ １ " is the density of hydrogen contained in the gas mixture at standard state. "ρ ２ " is the density of nitrogen contained in the gas mixture at standard state. "ρ ｗ " is the density of water vapor contained in the mixed gas. Furthermore, "x" is the hydrogen concentration. The density ρ １ , the density of nitrogen ρ ２ , and the density of water vapor ρ ｗ is stored in advance in the storage unit 24.

[0153]

[0154] The water vapor concentration measurement unit 209B calculates the water vapor concentration when at least the first gas (hydrogen) is flowing through the flow path 101 and the second gas (nitrogen) is not flowing. The water vapor concentration measurement unit 209B calculates the water vapor concentration (first water vapor concentration) when the hydrogen concentration is set to "1." Specifically, the water vapor concentration measurement unit 209B calculates the first water vapor concentration by substituting the value "1" for "x" in Equation 17.

[0155] The water vapor concentration measurement unit 209B calculates the water vapor concentration when at least the second gas flows through the flow path 101 and the first gas does not flow through the flow path 101. The water vapor concentration measurement unit 209B calculates the water vapor concentration (second water vapor concentration) when the hydrogen concentration is set to "0." Specifically, the water vapor concentration measurement unit 209B calculates the second water vapor concentration by substituting the value "0" for "x" in Equation 17.

[0156] The second acquisition unit 204B acquires first gas information related to the first gas, water vapor information related to water vapor, a gas constant R, a distance L between the pair of ultrasonic transmitter-receivers, and a reference temperature T ０ , and the first water vapor concentration measured by the water vapor concentration measuring unit 209B, the first reference propagation time t ｗ１ By calculating the first reference propagation time t ｗ１ Here, the second obtaining unit 204B obtains the first reference propagation time t ｗ１ Calculate.

[0157] The third acquisition unit 205B acquires second gas information related to the second gas, water vapor information related to water vapor, a gas constant R, a distance L between the pair of ultrasonic transmitter-receivers, and a reference temperature T ０ , and the second water vapor concentration measured by the water vapor concentration measuring unit 209B, the second reference propagation time t ｗ２ By calculating the second reference propagation time t ｗ２ Here, the third acquisition unit 205B acquires "M" for the second water vapor concentration and the first mathematical expression expressed by the above-mentioned mathematical expression 11. １ " to "M ２ " to "c ｐ１ " to "c ｐ２ " to "c ｖ１ " to "c ｖ２ ” respectively, the second reference propagation time t ｗ２ Calculate.

[0158] The concentration measurement unit 206A measures the propagation time t ｘ , the first reference propagation time t ｗ１ and the second reference propagation time t ｗ２Specifically, the concentration measurement unit 206A measures the concentration x of the first gas using the above-mentioned equation (12).

[0159] (2) Operation Here, the operation of the physical quantity measuring system 1B will be described with reference to FIG. 7, focusing on the differences from the operation of the physical quantity measuring system 1B.

[0160] The first signal processing unit 201 of the physical quantity measuring system 1B performs a process (first measurement process) similar to step S101 shown in FIG.

[0161] In step S102, the second signal processing unit 202B performs a second measurement process. Specifically, the second signal processing unit 202B calculates the temperature T measured by the temperature sensor 13 based on the signal output from the temperature sensor 13. ａ The second signal processing unit 202B determines the pressure measured by the pressure sensor 14 based on the signal output from the pressure sensor 14. Furthermore, the second signal processing unit 202B determines the humidity measured by the density sensor 16 based on the signal output from the density sensor 16.

[0162] In step S103, the water vapor concentration measurement unit 209B of the physical quantity measurement system 1B performs a water vapor concentration measurement process. Specifically, the water vapor concentration measurement unit 209B calculates the water vapor concentration x ｗ More specifically, the water vapor concentration measurement unit 209B calculates a first water vapor concentration when the hydrogen concentration is set to "1" and a second water vapor concentration when the hydrogen concentration is set to "0".

[0163] The physical quantity measuring system 1B performs the same process (acquisition process) as step S104 shown in Fig. 7. That is, the first acquisition unit 203 of the physical quantity measuring system 1B acquires the propagation time t ａ Measure the propagation time t ｘ The second acquisition unit 204B of the physical quantity measurement system 1B converts the first reference propagation time t ｗ１ By calculating the first reference propagation time t ｗ１ The third acquisition unit 205B of the physical quantity measuring system 1B acquires the second reference propagation time t ｗ２By calculating the second reference propagation time t ｗ２ Get.

[0164] The concentration measurement unit 206A of the physical quantity measurement system 1B performs the same process (concentration measurement process) as step S105 shown in FIG. 7. That is, the concentration measurement unit 206A of the physical quantity measurement system 1B measures the measured propagation time t ｘ , the first reference propagation time t ｗ１ and the second reference propagation time t ｗ２ More specifically, the concentration measurement unit 206A of the physical quantity measurement system 1B measures the concentration x of the first gas using the second reference propagation time t ｗ２ The measured propagation time t ｘ The first difference value obtained by subtracting the squared value of ｗ２ The first reference propagation time t ｗ１ The concentration of the first gas is calculated by dividing the calculated value by a second difference value obtained by subtracting the square of the calculated value.

[0165] The flow rate measurement unit 207 of the physical quantity measurement system 1B performs the same process (flow rate measurement process) as step S106 shown in Fig. 7. That is, the flow rate measurement unit 207 of the physical quantity measurement system 1B calculates the flow rate Q of the mixed gas in the flow path 101 by using the above-mentioned equation (7).

[0166] The physical quantity measuring system 1B executes the above operation every time the concentration of the first gas is measured.

[0167] (3) Advantages The physical quantity measuring system 1B of embodiment 2 includes a flow path 101, a pair of ultrasonic transmitter / receivers 11 and 12, a temperature sensor 13, a pressure sensor 14, a density sensor 16, a water vapor concentration measuring unit 209B, a first acquisition unit 203, a second acquisition unit 204B, a third acquisition unit 205B, and a concentration measuring unit 206A. A mixed gas containing a first gas and a second gas flows through the flow path 101. The pair of ultrasonic transmitter / receivers 11 and 12 transmit and receive ultrasonic waves and are arranged so that the ultrasonic waves intersect the flow of the mixed gas in the flow path 101. The temperature sensor 13 measures the temperature of the mixed gas. The pressure sensor 14 measures the pressure of the mixed gas. The density sensor 16 measures the density of the mixed gas. The first acquisition unit 203 acquires a measured propagation time corresponding to a reference temperature based on the propagation time of the ultrasonic waves obtained by transmitting and receiving the ultrasonic waves between the pair of ultrasonic transmitters and receivers 11 and 12, the temperature measured by the temperature sensor 13, and the reference temperature. The second acquisition unit 204B acquires a first reference propagation time of the ultrasonic waves when at least the first gas is flowing through the flow path 101 and the second gas is not flowing. The third acquisition unit 205B acquires a second reference propagation time of the ultrasonic waves when at least the second gas is flowing through the flow path 101 and the first gas is not flowing. The concentration measurement unit 206A measures the concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time. The water vapor concentration measurement unit 209B measures the water vapor concentration using the pressure of the mixed gas measured by the pressure sensor 14, the density measured by the density sensor 16, and the temperature measured by the temperature sensor 13. The water vapor concentration measuring unit 209B determines, as the water vapor concentrations, a first water vapor concentration when at least the first gas flows through the flow path 101 and the second gas does not flow, and a second water vapor concentration when at least the second gas flows through the flow path 101 and the first gas does not flow. The second acquiring unit 204B acquires the first reference propagation time by calculating the first reference propagation time when the first gas and water vapor flow through the flow path 101 and the second gas does not flow, based on the first gas information about the first gas, the water vapor information about the water vapor, the gas constant, the distance between the pair of ultrasonic transmitter / receivers 11, 12, the reference temperature, and the first water vapor concentration.The third acquisition unit 205B acquires the second reference propagation time by calculating a second reference propagation time when the second gas and water vapor flow through the flow path 101 and the first gas does not flow, based on the second gas information, water vapor information, gas constant, distance between the pair of ultrasonic transmitter / receivers, reference temperature, and second water vapor concentration related to the second gas. Here, the first water vapor concentration is the concentration of water vapor when at least the first gas flows through the flow path 101 and the second gas does not flow. The second water vapor concentration is the concentration of water vapor when at least the second gas flows through the flow path 101 and the first gas does not flow.

[0168] According to this configuration, the concentration of the first gas is measured using the measured propagation time, the first reference propagation time, and the second reference propagation time, so that the concentration of the gas contained in the mixed gas can be measured using a measurement method different from conventional measurement methods.

[0169] In the third embodiment, similarly to the second embodiment, the mixed gas contains water vapor, which is a polyatomic molecule, and the first gas and the second gas, which are diatomic molecules. Therefore, in the second embodiment, when calculating the first reference propagation time and the second reference propagation time, the first mathematical expression expressed by the mathematical expression 11 and the second mathematical expression 12 are used. １ " to "M ２ " to "c ｐ１ " to "c ｐ２ " to "c ｖ１ " to "c ｖ２ " is used. This makes it possible to correct the first reference propagation time of the first gas and the second reference propagation time of the second gas in accordance with the concentration of water vapor.

[0170] At least one of Modifications 3, 4, and 5 of Embodiment 1 may be applied to Embodiment 3. At least one of Modifications 1 to 3 of Embodiment 2 may be applied to Embodiment 3.

[0171] (Other Modifications) The above embodiment is merely one of various embodiments of the present disclosure. The above embodiment can be modified in various ways depending on the design and the like as long as the object of the present disclosure can be achieved.

[0172] Furthermore, functions similar to those of the physical quantity measurement systems 1, 1A, and 1B may be embodied as a physical quantity measurement method, a computer program, a non-transitory recording medium on which a program is recorded, or the like. A physical quantity measurement method according to one aspect is used in the physical quantity measurement systems 1, 1A, and 1B, each including a flow path 101, a pair of ultrasonic transmitters and receivers 11 and 12, and a temperature sensor 13. A mixed gas containing a first gas and a second gas flows through the flow path 101. The pair of ultrasonic transmitters and receivers 11 and 12 transmit and receive ultrasonic waves, and are arranged so that the ultrasonic waves cross the flow of the mixed gas in the flow path 101. The temperature sensor 13 measures the temperature of the mixed gas. The physical quantity measurement method includes a first acquisition step, a second acquisition step, a third acquisition step, and a concentration measurement unit step. In the first acquisition step, a measured propagation time corresponding to a reference temperature is acquired based on the propagation time of the ultrasonic waves obtained by transmitting and receiving the ultrasonic waves between the pair of ultrasonic transmitters and receivers 11 and 12, the temperature measured by the temperature sensor 13, and a reference temperature. In the second acquisition step, a first reference propagation time of the ultrasonic wave is acquired when at least the first gas is flowing through the flow path 101 and the second gas is not flowing. In the third acquisition step, a second reference propagation time of the ultrasonic wave is acquired when at least the second gas is flowing through the flow path 101 and the first gas is not flowing. In the concentration measurement step, the concentration of the first gas is measured using the measured propagation time, the first reference propagation time, and the second reference propagation time. A program according to one aspect is a program for causing a computer system to function as the above-described physical quantity measurement method.

[0173] The physical quantity measurement systems 1, 1A, and 1B in the present disclosure include a computer system. The computer system is primarily composed of a processor and a memory as hardware. The processor executes a program stored in the memory of the computer system to realize the functions of the physical quantity measurement systems 1, 1A, and 1B in the present disclosure. The program may be pre-recorded in the memory of the computer system, provided via a telecommunications line, or provided by being recorded on a non-transitory recording medium readable by the computer system, such as a memory card, an optical disk, or a hard disk drive. The processor of the computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). The integrated circuits, such as ICs and LSIs, are referred to by different names depending on the degree of integration, and include integrated circuits called system LSIs, very large-scale integration (VLSIs), and ultra-large-scale integration (ULSIs). Furthermore, a field-programmable gate array (FPGA), which is programmed after the LSI is manufactured, or a logic device capable of reconfiguring the connections within the LSI or the circuit partitions within the LSI, can also be employed as a processor. Multiple electronic circuits may be integrated into a single chip or distributed across multiple chips. Multiple chips may be integrated into a single device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or more electronic circuits, including a semiconductor integrated circuit or a large-scale integrated circuit.

[0174] Furthermore, it is not essential for the physical quantity measurement systems 1, 1A, and 1B that multiple functions are integrated into one housing, and the components of the physical quantity measurement systems 1, 1A, and 1B may be distributed across multiple housings. Furthermore, at least some of the functions of the physical quantity measurement systems 1, 1A, and 1B may be realized by cloud computing or the like.

[0175] (Summary) As described above, the physical quantity measuring system (1; 1A; 1B) of the first aspect includes a flow path (101), a pair of ultrasonic transmitters and receivers (11, 12), a temperature sensor (13), a first acquisition unit (203), a second acquisition unit (204; 204A; 204B), a third acquisition unit (205; 205A; 205B), and a concentration measurement unit (206, 206A). A mixed gas containing a first gas and a second gas flows through the flow path (101). The pair of ultrasonic transmitters and receivers (11, 12) transmit and receive ultrasonic waves and are arranged so that the ultrasonic waves intersect the flow of the mixed gas in the flow path (101). The temperature sensor (13) measures the temperature of the mixed gas. The first acquisition unit (203) acquires a measured propagation time corresponding to a reference temperature based on the propagation time of ultrasonic waves obtained by transmitting and receiving ultrasonic waves between the pair of ultrasonic transmitters and receivers (11, 12), the temperature measured by the temperature sensor (13), and the reference temperature. The second acquisition unit (204; 204A; 204B) acquires a first reference propagation time of ultrasonic waves when at least a first gas flows through the flow path (101) and a second gas does not flow. The third acquisition unit (205; 205A; 205B) acquires a second reference propagation time of ultrasonic waves when at least a second gas flows through the flow path (101) and the first gas does not flow. The concentration measurement unit (206, 206A) measures the concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time.

[0176] According to this aspect, the concentration of the first gas is measured using the measured propagation time, the first reference propagation time, and the second reference propagation time, so that the concentration of the gas contained in the mixed gas can be measured using a measurement method different from conventional measurement methods.

[0177] In the physical quantity measurement system (1) of the second aspect, in the first aspect, the second acquisition unit (204) acquires the first reference propagation time calculated in advance from a predetermined storage area, and the third acquisition unit (205) acquires the second reference propagation time calculated in advance from a predetermined storage area.

[0178] According to this aspect, the concentration of the first gas can be easily measured by using the first reference propagation time and the second reference propagation time that are stored in advance.

[0179] In the physical quantity measurement system (1) of the third aspect, in the first aspect, the second acquisition unit (204) acquires the first reference propagation time by calculating the first reference propagation time corresponding to the reference temperature based on the pre-stored first propagation time, the temperature measured by the temperature sensor (13), and the reference temperature. The third acquisition unit (205) acquires the second reference propagation time by calculating the second reference propagation time corresponding to the reference temperature based on the pre-stored second propagation time, the temperature measured by the temperature sensor (13), and the reference temperature.

[0180] According to this aspect, the first reference propagation time is calculated based on the first measured propagation time that is stored in advance, and the second reference propagation time is calculated based on the second propagation time that is stored in advance, so that the first reference propagation time and the second reference propagation time can be easily obtained.

[0181] In a fourth aspect of the physical quantity measurement system (1A), the mixed gas further contains water vapor. The physical quantity measurement system (1A) further includes a pressure sensor (14), a humidity sensor (15), and a water vapor concentration measurement unit (209). The pressure sensor (14) measures the pressure of the mixed gas. The humidity sensor (15) measures the humidity of the mixed gas. The water vapor concentration measurement unit (209) measures the water vapor concentration using the pressure of the mixed gas measured by the pressure sensor (14), the humidity measured by the humidity sensor (15), and the temperature measured by the temperature sensor (13). The second acquisition unit (204A) acquires the first reference propagation time by calculating a first reference propagation time when the first gas and water vapor flow through the flow path (101) and the second gas does not flow, based on first gas information about the first gas, water vapor information about water vapor, a gas constant, the distance between the pair of ultrasonic transmitter-receivers (11, 12), the reference temperature, and the water vapor concentration measured by the water vapor concentration measurement unit (209). The third acquisition unit (205A) acquires the second reference propagation time by calculating a second reference propagation time when the second gas and water vapor flow through the flow path (101) and the first gas does not flow, based on second gas information about the second gas, the water vapor information, the gas constant, the distance between the pair of ultrasonic transmitter-receivers (11, 12), the reference temperature, and the water vapor concentration measured by the water vapor concentration measurement unit (209).

[0182] According to this aspect, even when the mixed gas contains water vapor, the concentration of the gas contained in the mixed gas can be measured using a measurement method that differs from conventional measurement methods.

[0183] In a fifth aspect of the physical quantity measurement system (1B), the mixed gas further contains water vapor. The physical quantity measurement system (1B) is further provided with a pressure sensor (14), a density sensor (16), and a water vapor concentration measurement unit (209B). The pressure sensor (14) measures the pressure of the mixed gas. The density sensor (16) measures the density of the mixed gas. The water vapor concentration measurement unit (209B) measures the water vapor concentration using the pressure of the mixed gas measured by the pressure sensor (14), the density measured by the density sensor (16), and the temperature measured by the temperature sensor (13). The water vapor concentration measurement unit (209B) determines, as the water vapor concentrations, a first water vapor concentration when at least a first gas flows through the flow path (101) and a second gas does not flow, and a second water vapor concentration when at least a second gas flows through the flow path (101) and the first gas does not flow. The second acquisition unit (204B) acquires the first reference propagation time by calculating a first reference propagation time when the first gas and water vapor flow through the flow path (101) and the second gas does not flow, based on first gas information about the first gas, water vapor information about water vapor, a gas constant, the distance between the pair of ultrasonic transmitter-receivers, the reference temperature, and the first water vapor concentration. The third acquisition unit (205B) acquires the second reference propagation time by calculating a second reference propagation time when the second gas and water vapor flow through the flow path (101) and the first gas does not flow, based on second gas information about the second gas, water vapor information, the gas constant, the distance between the pair of ultrasonic transmitter-receivers, the reference temperature, and the second water vapor concentration.

[0184] According to this aspect, even when the mixed gas contains water vapor, the concentration of the gas contained in the mixed gas can be measured using a measurement method that differs from conventional measurement methods.

[0185] In a sixth aspect of the physical quantity measuring system (1A; 1B) of the fourth or fifth aspect, the first gas information includes a first molecular weight of the first gas and a first specific heat ratio of the first gas. The second gas information includes a second molecular weight of the second gas and a second specific heat ratio of the second gas. The water vapor information includes a third molecular weight of the water vapor and a third specific heat ratio of the water vapor.

[0186] According to this aspect, the first reference propagation time and the second reference propagation time are calculated using the molecular weight and specific heat ratio of the corresponding gas, so that the first reference propagation time and the second reference propagation time can be easily calculated.

[0187] In a seventh aspect of the physical quantity measurement system (1A; 1B) of the sixth aspect, the information about the first gas includes, as a first specific heat ratio, a constant pressure molar specific heat of the first gas and a constant volume molar specific heat of the first gas. The information about the second gas includes, as a second specific heat ratio, a constant pressure molar specific heat of the second gas and a constant volume molar specific heat of the second gas. The information about water vapor includes, as a third specific heat ratio, a constant pressure molar specific heat of the water vapor and a constant volume molar specific heat of the water vapor.

[0188] According to this aspect, the first reference propagation time and the second reference propagation time are calculated using the molecular weight, constant pressure molar specific heat, and constant volume molar specific heat of the corresponding gas, so that the first reference propagation time and the second reference propagation time can be easily calculated.

[0189] In a physical quantity measurement system (1A) of an eighth aspect, in the first aspect, the mixed gas further contains water vapor. The physical quantity measurement system (1A) further includes a pressure sensor (14), a humidity sensor (15), and a water vapor concentration measurement unit (209). The pressure sensor (14) measures the pressure of the mixed gas. The humidity sensor (15) measures the humidity of the mixed gas. The water vapor concentration measurement unit (209) measures the water vapor concentration using the pressure of the mixed gas measured by the pressure sensor (14), the humidity measured by the humidity sensor (15), and the temperature measured by the temperature sensor (13). The second acquisition unit (204A) performs temperature conversion based on the temperature measured by the temperature sensor (13) and a reference temperature when the first propagation time was measured, and humidity conversion based on the water vapor concentration measured by the water vapor concentration measurement unit (209) for the pre-stored first propagation time, thereby acquiring a first reference propagation time. The third acquisition unit (205A) performs temperature conversion based on the temperature measured by the temperature sensor (13) when the second propagation time was measured and the reference temperature, and humidity conversion based on the water vapor concentration measured by the water vapor concentration measurement unit (209) for the pre-stored second propagation time, and acquires the second reference propagation time.

[0190] According to this aspect, the first reference propagation time is calculated based on the first propagation time that has been stored in advance, and the second reference propagation time is calculated based on the second propagation time that has been stored in advance, so that the first reference propagation time and the second reference propagation time can be easily obtained.

[0191] In a ninth aspect of the physical quantity measurement system (1B), the mixed gas further contains water vapor. The physical quantity measurement system (1B) is further provided with a pressure sensor (14), a density sensor (16), and a water vapor concentration measurement unit (209B). The pressure sensor (14) measures the pressure of the mixed gas. The density sensor (16) measures the density of the mixed gas. The water vapor concentration measurement unit (209B) measures the water vapor concentration using the pressure of the mixed gas measured by the pressure sensor (14), the density measured by the density sensor (16), and the temperature measured by the temperature sensor (13). The water vapor concentration measurement unit (209B) determines, as the water vapor concentrations, a first water vapor concentration when at least a first gas flows through the flow path (101) and a second gas does not flow, and a second water vapor concentration when at least a second gas flows through the flow path (101) and the first gas does not flow. The second acquisition unit (204B) performs temperature conversion based on the temperature measured by the temperature sensor (13) when the first propagation time was measured and the reference temperature and humidity conversion based on the first water vapor concentration for the pre-stored first propagation time, thereby acquiring a first reference propagation time. The third acquisition unit (205B) performs temperature conversion based on the temperature measured by the temperature sensor (13) when the second propagation time was measured and the reference temperature and humidity conversion based on the second water vapor concentration for the pre-stored second propagation time, thereby acquiring a second reference propagation time.

[0192] According to this aspect, the first reference propagation time is calculated based on the first propagation time that has been stored in advance, and the second reference propagation time is calculated based on the second propagation time that has been stored in advance, so that the first reference propagation time and the second reference propagation time can be easily obtained.

[0193] In the physical quantity measurement system (1; 1A; 1B) of the tenth aspect, in any of the first to ninth aspects, the concentration measurement unit (206, 206A) calculates the concentration of the first gas by dividing a first difference value obtained by subtracting the square of the measured propagation time from the square of the second reference propagation time by a second difference value obtained by subtracting the square of the first reference propagation time from the square of the second reference propagation time.

[0194] According to this aspect, the concentration of the first gas can be calculated by using a formula (e.g., Formula 6 or Formula 12) that uses the measured propagation time, the first reference propagation time, and the second reference propagation time, eliminating the need to calculate the concentration of the first gas using a complex formula, thereby reducing the processing load on the physical quantity measurement system (1, 1A).

[0195] In the physical quantity measuring system (1; 1A; 1B) of the eleventh aspect, in any one of the first to tenth aspects, both the first gas and the second gas have the same molecular structure.

[0196] According to this aspect, it is possible to measure the concentration of either the first gas or the second gas, which have the same molecular structure.

[0197] A physical quantity measuring system (1; 1A; 1B) of a twelfth aspect is any one of the first to eleventh aspects, and includes a plurality of temperature sensors (13). The temperature of the mixed gas is an average value of the temperatures measured by each of the plurality of temperature sensors (13).

[0198] According to this embodiment, the accuracy of measuring the temperature of the gas mixture can be improved.

[0199] REFERENCE SIGNS LIST 1, 1A, 1B Physical quantity measurement system 11 Ultrasonic transmitter / receiver (first ultrasonic transmitter / receiver) 12 Ultrasonic transmitter / receiver (second ultrasonic transmitter / receiver) 13 Temperature sensor 14 Pressure sensor 15 Humidity sensor 16 Density sensor 101 Flow path 203 First acquisition unit 204, 204A, 204B Second acquisition unit 205, 205A, 205B Third acquisition unit 206, 206A Concentration measurement unit 209, 209B Water vapor concentration measurement unit

Claims

1. A physical quantity measurement system comprising: a flow path through which a mixed gas containing a first gas and a second gas flows; a pair of ultrasonic transmitters and receivers that transmit and receive ultrasonic waves and are positioned so that the ultrasonic waves cross the flow of the mixed gas in the flow path; a temperature sensor that measures the temperature of the mixed gas; a first acquisition unit that acquires a measured propagation time corresponding to a reference temperature based on a propagation time of the ultrasonic wave obtained by the transmission and reception of the ultrasonic waves between the pair of ultrasonic transmitters and receivers, the temperature measured by the temperature sensor, and a reference temperature; a second acquisition unit that acquires a first reference propagation time of the ultrasonic wave when at least the first gas flows in the flow path and the second gas is not flowing; a third acquisition unit that acquires a second reference propagation time of the ultrasonic wave when at least the second gas flows in the flow path and the first gas is not flowing; and a concentration measurement unit that measures a concentration of the first gas using the measured propagation time, the first reference propagation time, and the second reference propagation time.

2. The physical quantity measuring system according to claim 1, wherein the second acquisition unit acquires the first reference propagation time calculated in advance from a specified memory area, and the third acquisition unit acquires the second reference propagation time calculated in advance from the specified memory area.

3. The physical quantity measurement system of claim 1, wherein the second acquisition unit acquires the first reference propagation time by calculating the first reference propagation time corresponding to the reference temperature based on a pre-stored first propagation time, the temperature measured by the temperature sensor when the first propagation time is measured, and the reference temperature; and the third acquisition unit acquires the second reference propagation time by calculating the second reference propagation time corresponding to the reference temperature based on a pre-stored second propagation time, the temperature measured by the temperature sensor, and the reference temperature.

4. The mixed gas further contains water vapor, and the physical quantity measurement system further comprises a pressure sensor that measures a pressure of the mixed gas, a humidity sensor that measures humidity of the mixed gas, and a water vapor concentration measurement unit that measures a water vapor concentration using the pressure of the mixed gas measured by the pressure sensor, the humidity measured by the humidity sensor, and the temperature measured by the temperature sensor, and the second acquisition unit acquires the first reference propagation time by calculating the first reference propagation time when the first gas and the water vapor flow through the flow path and the second gas does not flow based on first gas information about the first gas, water vapor information about the water vapor, a gas constant, the distance between the pair of ultrasonic transmitter / receivers, the reference temperature, and the water vapor concentration measured by the water vapor concentration measurement unit, and the third acquisition unit acquires the first reference propagation time by calculating the first reference propagation time when the first gas and the water vapor flow through the flow path and the second gas does not flow based on the ... the water vapor information about the water vapor, a gas constant, the distance between the pair of ultrasonic transmitter / receivers, the reference temperature, and the water vapor concentration measured by the water vapor concentration measurement unit, and 2. The physical quantity measuring system according to claim 1, wherein the second reference propagation time is acquired by calculating the second reference propagation time when the second gas and the water vapor flow through the flow path and the first gas does not flow, based on second gas information related to the second gas, the water vapor information, the gas constant, the distance between the pair of ultrasonic transmitters, the reference temperature, and the water vapor concentration measured by the water vapor concentration measuring unit.

5. The mixed gas further contains water vapor, and the physical quantity measurement system further comprises: a pressure sensor that measures a pressure of the mixed gas; a density sensor that measures a density of the mixed gas; and a water vapor concentration measurement unit that measures a water vapor concentration using the pressure of the mixed gas measured by the pressure sensor, the density measured by the density sensor, and the temperature measured by the temperature sensor, and the water vapor concentration measurement unit determines, as the water vapor concentration, a first water vapor concentration when at least the first gas flows through the flow path and the second gas does not flow, and a second water vapor concentration when at least the second gas flows through the flow path and the first gas does not flow, and the second acquisition unit 2. The physical quantity measuring system according to claim 1, wherein the first reference propagation time is acquired by calculating the first reference propagation time when the first gas and the water vapor flow through the flow path and the second gas does not flow, based on first gas information about the first gas, water vapor information about the water vapor, a gas constant, the distance between the pair of ultrasonic transmitters / receivers, the reference temperature, and the first water vapor concentration; and the third acquisition unit acquires the second reference propagation time by calculating the second reference propagation time when the second gas and the water vapor flow through the flow path and the first gas does not flow, based on second gas information about the second gas, the water vapor information, the gas constant, the distance between the pair of ultrasonic transmitters / receivers, the reference temperature, and the second water vapor concentration.

6. A physical quantity measuring system as described in claim 4 or 5, wherein the first gas information includes a first molecular weight of the first gas and a first specific heat ratio of the first gas, the second gas information includes a second molecular weight of the second gas and a second specific heat ratio of the second gas, and the water vapor information includes a third molecular weight of the water vapor and a third specific heat ratio of the water vapor.

7. The physical quantity measuring system of claim 6, wherein the information regarding the first gas includes, as the first specific heat ratio, a constant pressure molar specific heat of the first gas and a constant volume molar specific heat of the first gas; the information regarding the second gas includes, as the second specific heat ratio, a constant pressure molar specific heat of the second gas and a constant volume molar specific heat of the second gas; and the information regarding the water vapor includes, as the third specific heat ratio, a constant pressure molar specific heat of the water vapor and a constant volume molar specific heat of the water vapor.

8. The physical quantity measurement system according to claim 1, wherein the mixed gas further contains water vapor, the physical quantity measurement system further comprises: a pressure sensor that measures a pressure of the mixed gas; a humidity sensor that measures humidity of the mixed gas; and a water vapor concentration measurement unit that measures a water vapor concentration using the pressure of the mixed gas measured by the pressure sensor, the humidity measured by the humidity sensor, and the temperature measured by the temperature sensor, wherein the second acquisition unit performs, for a pre-stored first propagation time, temperature conversion based on the temperature measured by the temperature sensor and the reference temperature when the first propagation time is measured, and humidity conversion based on the water vapor concentration measured by the water vapor concentration measurement unit, to obtain the first reference propagation time, and the third acquisition unit performs, for a pre-stored second propagation time, temperature conversion based on the temperature measured by the temperature sensor and the reference temperature when the second propagation time is measured, and humidity conversion based on the water vapor concentration measured by the water vapor concentration measurement unit, to obtain the second reference propagation time.

9. The mixed gas further contains water vapor, and the physical quantity measurement system further comprises: a pressure sensor that measures the pressure of the mixed gas; a density sensor that measures the density of the mixed gas; and a water vapor concentration measurement unit that measures a water vapor concentration using the pressure of the mixed gas measured by the pressure sensor, the density measured by the density sensor, and the temperature measured by the temperature sensor, and the water vapor concentration measurement unit determines, as the water vapor concentration, a first water vapor concentration when at least the first gas flows through the flow path and the second gas does not flow, and a second water vapor concentration when at least the second gas flows through the flow path and the first gas does not flow, and the second acquisition unit performs, for a pre-stored first propagation time, temperature conversion based on the temperature and the reference temperature measured by the temperature sensor when the first propagation time is measured, and humidity conversion based on the first water vapor concentration, to obtain the first reference propagation time, and the third acquisition unit performs 2. The physical quantity measuring system according to claim 1, further comprising: a temperature conversion based on the temperature measured by the temperature sensor when the second propagation time is measured and the reference temperature; and a humidity conversion based on the second water vapor concentration, for a pre-stored second propagation time, to obtain the second reference propagation time.

10. A physical quantity measuring system according to any one of claims 1 to 9, wherein the concentration measuring unit calculates the concentration of the first gas by dividing a first difference value, obtained by subtracting the squared value of the measured propagation time from the squared value of the second reference propagation time, by a second difference value, obtained by subtracting the squared value of the first reference propagation time from the squared value of the second reference propagation time.

11. A physical quantity measuring system according to any one of claims 1 to 10, wherein the first gas and the second gas have the same molecular structure.

12. A physical quantity measuring system according to any one of claims 1 to 11, comprising a plurality of the temperature sensors, and wherein the temperature of the mixed gas is an average value of the temperatures measured by each of the plurality of the temperature sensors.

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