Hydrogen flow / concentration meter

Abstract

An object of the present disclosure is to provide a hydrogen flow / concentration meter that allows accurate measurement of the flow and concentration of hydrogen in a mixed gas even when the mixed gas including hydrogen and water vapor is in a high humidity state. A hydrogen flow / concentration meter (100) is provided with a measurement channel (1), a pair of ultrasonic transducers (2, 3), a sensor unit (4b), and an arithmetic unit (30). Comprising hydrogen and water vapor flows through the measurement flow channel (1). A pair of ultrasonic transducers (2, 3) is arranged in the measurement flow channel (1) across the flow of the mixed gas. A sensor unit (4b) measures the temperature, pressure, and humidity of the mixed gas. The calculation means (30) calculates the flow rate and concentration of hydrogen in the mixed gas using the propagation time between the pair of ultrasonic transducers (2, 3) and the measured values of the temperature, pressure, and humidity of the mixed gas.

Description

Technical Field

[0001] The present disclosure relates generally to hydrogen flow / concentration meters, and more particularly to configurations for hydrogen flow / concentration meters using ultrasonic waves. Background Art

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

[0003] A method using ultrasonic waves is known in the art as a method for measuring the concentration of a mixed gas including hydrogen (for example, see Patent Document 1).

[0004] The device disclosed in Patent Document 1 first determines the speed of sound in a mixed gas based on the measured propagation time of ultrasonic waves. Next, the device uses this value and the measured temperature to determine the average molecular weight of the mixed gas. Subsequently, the device uses the known molecular weights of the various component gases to determine the concentration of hydrogen, one of the multiple component gases.

[0005] However, Patent Document 1, which has a known configuration, does not teach how to calculate the concentration of hydrogen when determining the concentration of hydrogen gas, a component gas, when the target gas is in a high humidity condition containing water vapor. Therefore, measuring the concentration of hydrogen in a mixed gas under high humidity conditions is a challenge.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-91489 Summary of the Invention

[0009] In view of the foregoing background, an object of the present disclosure is to provide a hydrogen flow / concentration meter that allows the flow rate and concentration of hydrogen included in a mixed gas to be measured with high accuracy even if the mixed gas including hydrogen and water vapor is under high humidity conditions.

[0010] In order to overcome the problems of the prior art, a hydrogen flow / concentration meter according to one aspect of the present disclosure includes: a measuring flow channel for a mixed gas including hydrogen and water vapor to flow through; a pair of ultrasonic transducers, which are arranged in the measuring flow channel in a manner across the flow of the mixed gas; a transceiver circuit, which is used to transmit and receive ultrasonic waves between the pair of ultrasonic transducers; a first signal processor, which is used to process the signal provided by the transceiver circuit; a sensor unit, which is used to measure the temperature, pressure and humidity of the mixed gas; a second signal processor, which is used to obtain corresponding measurement values ​​of the temperature, pressure and humidity of the mixed gas using the sensor unit; and an operation unit, which is used to calculate the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers obtained by the first signal processor, but also the corresponding measurement values ​​of the temperature, pressure and humidity obtained by the second signal processor.

[0011] According to another aspect of the present disclosure, a hydrogen flow / concentration meter includes: a measuring flow channel through which a mixed gas including hydrogen and water vapor flows; a pair of ultrasonic transducers, which are arranged in the measuring flow channel in a manner across the flow of the mixed gas; a transceiver circuit, which is used to transmit and receive ultrasonic waves between the pair of ultrasonic transducers; a first signal processor, which is used to process the signal provided by the transceiver circuit; a second signal processor, which is used to obtain corresponding measurement values ​​of the temperature, pressure and humidity of the mixed gas from an external device; and an operation unit, which is used to calculate the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers obtained by the first signal processor, but also the corresponding measurement values ​​of the temperature, the pressure and the humidity obtained by the second signal processor.

[0012] According to another aspect of the present disclosure, a hydrogen flow / concentration meter includes: a measurement flow channel through which a mixed gas including hydrogen and water vapor flows; a pair of ultrasonic transducers arranged in the measurement flow channel in a manner astride the flow of the mixed gas; a transceiver circuit for transmitting and receiving ultrasonic waves between the pair of ultrasonic transducers; a first signal processor for processing signals provided by the transceiver circuit; a sensor unit for measuring at least one of the temperature, pressure, and humidity of the mixed gas; a second signal processor for obtaining a measured value of at least one of the temperature, pressure, and humidity of the mixed gas using the sensor unit and acquiring values ​​of the remaining ones of the temperature, pressure, and humidity of the mixed gas except the at least one from an external device as measured values; and an operation unit for calculating the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers obtained by the first signal processor but also the corresponding measured values ​​of the temperature, pressure, and humidity obtained by the second signal processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [ Figure 1 ] Figure 1 is a cross-sectional view showing a configuration for a hydrogen flow / concentration meter according to a first embodiment of the present disclosure.

[0014] [ Figure 2 ] Figure 2 According to the first embodiment of the present disclosure, Figure 1 A partial cross-sectional view taken along plane AA is shown.

[0015] [ Figure 3 ] Figure 3 1 is a perspective view showing the appearance of a flow channel portion of the hydrogen flow / concentration meter according to the first embodiment of the present disclosure.

[0016] [ Figure 4 ] Figure 4 It is an exploded perspective view showing each constituent element of the hydrogen flow / concentration meter according to the first embodiment of the present disclosure.

[0017] [ Figure 5 ] Figure 5 is a cross-sectional view showing a configuration for a hydrogen flow / concentration meter according to a second embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] A hydrogen flow / concentration meter according to a first aspect includes: a measurement flow channel through which a mixed gas including hydrogen and water vapor flows; a pair of ultrasonic transducers arranged in the measurement flow channel so as to straddle the flow of the mixed gas; a transceiver circuit for transmitting and receiving ultrasonic waves between the pair of ultrasonic transducers; a first signal processor for processing signals provided by the transceiver circuit; a sensor unit for measuring the temperature, pressure, and humidity of the mixed gas; a second signal processor for obtaining respective measured values ​​of the temperature, pressure, and humidity of the mixed gas using the sensor unit; and an arithmetic unit for calculating the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers obtained by the first signal processor but also the respective measured values ​​of the temperature, pressure, and humidity obtained by the second signal processor. A hydrogen flow / concentration meter having such a configuration can calculate the flow rate and concentration of hydrogen included in the flow, thereby allowing accurate measurement of the flow rate and concentration of hydrogen using the temperature, pressure, and relative humidity measured thereby, even when the target gas being measured is under high humidity conditions. Therefore, highly practical detection of hydrogen flow rate and concentration is achieved.

[0019] In the hydrogen flow / concentration meter according to the second aspect, which can be implemented in combination with the first aspect, the measurement flow path is constructed as a multi-layered flow path divided by partitions, thereby helping to rectify the flow and stabilize turbulence, thereby reducing changes in the measured physical quantities (i.e., temperature, pressure, and relative humidity). As a result, the flow rate and concentration can be measured with good stability.

[0020] The embodiments will now be described in detail with reference to the accompanying drawings. Note that unnecessary detailed descriptions will be omitted. For example, detailed descriptions of already known matters and repeated descriptions of substantially identical configurations will be omitted. This is done to avoid making the following description excessively lengthy, thereby helping those skilled in the art to easily understand the present disclosure.

[0021] In addition, it is noted that the accompanying drawings and the following description are provided to assist those skilled in the art in fully understanding the present disclosure, and should not be construed as limiting the scope of the present disclosure defined by the appended claims.

[0022] (First embodiment)

[0023] Will refer to Figures 1 to 4 A first embodiment is described.

[0024] [1-1. Structure]

[0025] Figure 1 Shown are a cross section of a main body and respective constituent elements of a hydrogen flow / concentration meter according to a first embodiment of the present disclosure. Figure 2 It is along Figure 1 A partial cross-sectional view taken along plane AA is shown.

[0026] like Figure 1 and Figure 2 As shown, a measurement flow channel 1, through which a measured fluid, such as a mixed gas including hydrogen, flows, is formed along the centerline of a flow channel body 17. The measurement flow channel 1 is provided with: a pair of ultrasonic transducers 2, 3, which are respectively arranged at upstream and downstream points across the flow of the measured fluid; a transceiver circuit 4a for transmitting and receiving ultrasonic waves between the pair of ultrasonic transducers 2, 3; and a first signal processor 5a for processing signals provided by the transceiver circuit 4a.

[0027] The transceiver circuit 4a is electrically connected to the ultrasonic transducers 2 and 3 to transmit and receive signals to and from the ultrasonic transducers 2 and 3. A first signal processor 5a is connected to the transceiver circuit 4a to process the signals. Reference numerals S1 and S2 written at respective ends of a line extending from the transceiver circuit 4a indicate that the transceiver circuit 4a is connected to the ultrasonic transducers 2 and 3.

[0028] An ultrasonic wave propagation path 6 through which ultrasonic waves propagate is formed between the ultrasonic transducers 2 and 3 .

[0029] In this embodiment, the rectangular cross-section of the measurement flow channel 1 having a height H and a width W is divided into six sections in the direction of the height H by five partitions 7, thereby forming a multi-layer flow channel 8. This configuration not only increases the aspect ratio of the flow channel cross-section of each layer of the multi-layer flow channel 8 to convert the flow into a two-dimensional flow, but also reduces the Reynolds number, thereby rectifying the flow and stabilizing turbulence.

[0030] In addition, a sensor unit 4b for measuring the temperature, pressure and humidity of the measured fluid is provided. The sensor unit 4b is composed of a temperature sensor, a pressure sensor and a relative humidity sensor as described below.

[0031] In order to measure the temperature of the fluid to be measured flowing through the ultrasonic propagation path 6 , temperature sensors 9 and 10 are respectively provided at the inlet and outlet of the measurement flow channel 1 .

[0032] In addition, a pressure sensor 11 for measuring the pressure of the measured fluid is arranged in the middle along the flow direction of the ultrasonic propagation path 6. In the ultrasonic propagation path 6 having a multi-layer structure, the pressure sensor 11 is configured to measure the pressure through a pressure connection hole 12 connected to the outermost layer of the multi-layer structure.

[0033] Furthermore, to avoid affecting the flow through the ultrasonic propagation path 6 , the relative humidity sensor 13 is arranged downstream of the ultrasonic propagation path 6 and is inserted obliquely from the upper surface of the flow channel body 17 toward a downstream position with respect to the flow direction, thereby forming an acute angle θ.

[0034] The peripheral path 15a is formed as a gap around the periphery of the relative humidity sensor 13, and provides a connection path 16 connected to the multi-layer flow channel 8 through the assembly hole 15 of the relative humidity sensor 13. This connection path 16 is provided substantially perpendicular to the assembly hole 15 of the relative humidity sensor 13. Thus, a bypass flow channel is formed by the connection path 16 extending obliquely upward from the multi-layer flow channel 8 and the peripheral path 15a opening at a downstream position on the multi-layer flow channel 8.

[0035] Temperature, pressure and humidity are measured by the sensor unit 4 b , which is composed of the temperature sensors 9 , 10 , the pressure sensor 11 and the relative humidity sensor 13 , and signals obtained therefrom are processed by the second signal processor 5 b .

[0036] Note that the electrical signals provided by the various sensors are actually connected to the sensor unit 4b via separate lines. For convenience, the separate lines are indicated by a single line in the drawing. Furthermore, reference numerals Tp1, Tp2, Pr, and Hu written at the respective ends of the branches of this single line indicate connections to the temperature sensors 9 and 10, the pressure sensor 11, and the relative humidity sensor 13, respectively.

[0037] The arithmetic unit 30 performs arithmetic processing based on the signal supplied from the first signal processor 5 a and the signal supplied from the second signal processor 5 b .

[0038] In this configuration, temperature sensors 9 , 10 are respectively arranged at upstream and downstream positions on the ultrasonic wave propagation path 6 , thereby allowing the temperature of the fluid flowing through the ultrasonic wave propagation path 6 to be accurately estimated without affecting the propagation or flow of ultrasonic waves.

[0039] Furthermore, the pressure sensor 11 is arranged in the middle of the ultrasonic wave propagation path 6 in such a manner as to face the outermost layer of the multi-layer flow channel 8, thereby reducing the possibility of the pressure connection hole 12 affecting the flow of other flow channels in the multi-layer flow channel reaching the ultrasonic wave propagation path 6. Therefore, this allows the pressure of the fluid flowing through the ultrasonic wave propagation path 6 to be estimated without significantly affecting the propagation or flow of the ultrasonic wave.

[0040] In such measurement of relative humidity, if water included in the measured fluid adheres to, for example, relative humidity sensor 13 due to condensation, the accuracy of the measurement may be affected. To avoid this, a bypass flow channel is formed so as to extend from multi-layer flow channel 8 via connection path 16 and along peripheral path 15a left as a gap on the outer periphery of relative humidity sensor 13, thereby connecting to a downstream position on the multi-layer flow channel.

[0041] This allows the water droplets to flow out without accumulating there even if condensation occurs around the relative humidity sensor 13. If the flow rate is high, this bypass flow channel allows the water droplets to be blown toward the downstream end. Furthermore, even if the flow rate is low, even when the measurement flow channel 1 is Figure 1 Even in the horizontal arrangement shown, water droplets will still fall due to gravity, because the relative humidity sensor 13 and the peripheral path 15 a and the connecting path 16 surrounding the relative humidity sensor 13 are inclined with respect to the flow direction in the measuring flow channel 1 .

[0042] Furthermore, the peripheral path 15a and the connecting path 16 are inclined in opposite directions relative to the vertical direction defined relative to the measuring flow channel 1. Therefore, regardless of whether the outlet of the measuring flow channel 1 is inclined upward or downward, the peripheral path 15a or the connecting path 16 will be inclined downward, thereby ensuring that the water droplets will fall due to gravity.

[0043] Note that in order to facilitate the water droplets to fall due to gravity, it is preferable that the measurement flow channel 1 is configured so that its outlet end is tilted upward, so that the water droplets can more easily fall toward the connection path 16 having a wider cross-sectional area. Depending on the situation, the measurement flow channel 1 can even be configured vertically so that its outlet end is vertically upward.

[0044] [1-2. Operation]

[0045] Next, how the hydrogen flow / concentration meter according to the present disclosure operates will be described.

[0046] The measured fluid is a mixed gas including hydrogen and is Figure 1 The hydrogen flows into the hydrogen flow / concentration meter in the direction indicated by the hollow arrow.

[0047] In this case, ultrasonic waves are transmitted and received between the ultrasonic transducers 2 and 3 via the ultrasonic propagation path 6. At the same time, the propagation time (tup) of the ultrasonic wave in the forward direction (i.e., from the downstream end toward the upstream end) and the propagation time (tdw) of the ultrasonic wave in the reverse direction (i.e., from the upstream end toward the downstream end) are measured by the transceiver circuit 4a and the first signal processor 5a.

[0048] The flow velocity is calculated by the arithmetic unit 30 based on the propagation time thus obtained by a known method, and is multiplied by the cross-sectional area of ​​the measurement flow channel 1 , thereby calculating the flow rate.

[0049] As will be described later, this value is corrected using the temperature obtained from the temperature sensors 9 , 10 and the pressure obtained from the pressure sensor 11 , thereby obtaining the flow rate (Q) under standard conditions.

[0050] Note that the flow rate of hydrogen forming only a portion of the flow rate (Q) thus obtained can be determined by obtaining the hydrogen concentration as will be described later and multiplying the flow rate (Q) by the hydrogen concentration.

[0051] The temperature of the fluid being measured can be measured by measuring the upstream temperature (T1) with a temperature sensor 9 located at an upstream position on the measurement flow channel 1 and measuring the downstream temperature (T2) with a temperature sensor 10 located at a downstream position on the measurement flow channel 1. The signal representing the upstream temperature and the signal representing the downstream temperature are loaded into and processed by the second signal processor 5b and then provided as the corresponding temperatures to the arithmetic unit 30. Based on these two temperatures, the arithmetic unit 30 calculates the average temperature (measured temperature Tm).

[0052] The pressure of the fluid being measured is measured by a pressure sensor 11 disposed in the middle of the ultrasonic wave propagation path 6 along the flow direction, wherein the flow is stabilized by the multi-layer flow channel 8. The signal provided by the pressure sensor 11 is loaded into and processed by the second signal processor 5b, and then provided to the arithmetic unit 30 as pressure (p).

[0053] The relative humidity of the measured fluid is measured by a relative humidity sensor 13 provided downstream of the ultrasonic wave propagation path 6. The signal provided by the relative humidity sensor 13 is loaded into and processed by the second signal processor 5b, and then provided to the operation unit 30 as a relative humidity value (h).

[0054] [1-3. Concentration measurement method]

[0055] Next, a description will be given of how to calculate the hydrogen concentration using the physical quantities thus measured (ie, propagation time, temperature, pressure, and relative humidity).

[0056] First, the concentration of a mixed gas of two types of gases can be obtained in the following procedure.

[0057] The speed of sound c, molecular weight M, heat capacity ratio γ, absolute temperature T, and gas constant R in a gas satisfy the following relationship.

[0058] [Mathematical formula 1]

[0059]

[0060] In this case, the sound speed c is calculated based on the distance L between the ultrasonic sensors and the measured propagation time t by the following equation: up , t dw The average value of t ave To calculate.

[0061] [Mathematical formula 2]

[0062]

[0063] Furthermore, if the physical properties of the two types of gases are set as Gas #1 (molecular weight M1, constant pressure specific heat C p1 , constant volume specific heat C v1 )) and gas #2 (molecular weight M2, constant pressure specific heat C p2 , constant volume specific heat C v2 )), and the concentration of gas #1 is x, then the molecular weight and heat capacity ratio of the mixed gas can be described as follows:

[0064] [Mathematical formula 3]

[0065] M=xM1+(1-x)M2 (3)

[0066] [Formula 4]

[0067]

[0068] The concentration x can be obtained by substituting equations (2) to (4) into equation (1), substituting the measured temperature Tm for the absolute temperature T into equation (1), and solving equation (1) with respect to x.

[0069] Next, the hydrogen concentration x in the mixed gas of three types of gases including water vapor (molecular weight M) added as the third gas can be obtained in the following procedure. w , constant pressure specific heat c pw , constant volume specific heat c vw ).

[0070] First, the relative humidity (H m ), pressure (P m ) and the measured temperature (T m ) to determine the water vapor concentration in the mixed gas. The water vapor concentration in the mixed gas can be described by Tetens' equation as follows.

[0071] [Formula 5]

[0072]

[0073] In this case, equation (1) can be described as follows by applying the same calculations as those expressed by equations (3) and (4).

[0074] [Formula 6]

[0075]

[0076] The hydrogen concentration x can be obtained by solving this equation (6).

[0077] If the average propagation time of hydrogen in actual measurement is t ave1 And the temperature is T m1 , and in equations (2) and (6) x = 1 and x w = 0, the actual distance between the ultrasonic sensors L = L1 can be obtained. Therefore, the hydrogen concentration can be measured with high accuracy.

[0078] Furthermore, if the average propagation time during the actual measurement of nitrogen is t ave2 And the temperature is T m2 , and in equations (2) and (6) x = 0 and x w =0, the actual distance between the ultrasonic sensors L=L2 can be obtained.

[0079] Ideally, L1 = L2 is satisfied. However, in reality, a difference between the distance L2 and the distance L1 may occur due to the difference between the theoretical value and the actual measured value and due to a fixed error involved in the conversion of the propagation time.

[0080] In this case, the speed of sound is calculated by taking the propagation time t ave Subtract the differential time t d Calculated corrected propagation time t ave -t d Defined by the following equation (7), the differential time t that allows L1=L2 to be satisfied is obtained d The distance L between the ultrasonic sensor (= L1 = L2).

[0081] [Formula 7]

[0082]

[0083] In this case, under the condition that L1=L2, the d = 0 as the initial value to obtain t d and L. Alternatively, t d and L can also be obtained algebraically through the following equations (8) and (9):

[0084] [Formula 8]

[0085]

[0086] [Formula 9]

[0087]

[0088] If the differential time t calculated by these equations (8) and (9) is used d If the distance L between the ultrasonic sensor and the ultrasonic sensor is used to calculate equations (6) and (7), the concentration can be measured more accurately.

[0089] [1-4. Advantages]

[0090] As can be seen from the foregoing description, the hydrogen flow / concentration meter 100 according to this embodiment includes: a measurement flow channel 1 through which a mixed gas including hydrogen and water vapor flows; a pair of ultrasonic transducers 2 and 3 arranged in the measurement flow channel 1 so as to straddle the flow of the mixed gas; a transceiver circuit 4a for transmitting and receiving ultrasonic waves between the pair of ultrasonic transducers 2 and 3; a first signal processor 5a for processing signals provided by the transceiver circuit 4a; a sensor unit 4b for measuring the temperature, pressure, and humidity of the mixed gas; a second signal processor 5b for obtaining respective measured values ​​of the temperature, pressure, and humidity of the mixed gas using the sensor unit 4b; and an arithmetic unit 30 for calculating the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers 2 and 3 obtained by the first signal processor 5a, but also the respective measured values ​​of the temperature, pressure, and humidity obtained by the second signal processor 5b. This allows the hydrogen concentration in a mixed gas including hydrogen to be measured with sufficient accuracy even in a high-humidity environment, thereby enabling the flow rate and concentration to be measured with practical accuracy.

[0091] Furthermore, the measurement flow channel 1 is constructed as a multi-layered flow channel divided by partitions 7, thereby helping to rectify the flow and thereby reducing variations in the measured physical quantities (i.e., temperature, pressure, and relative humidity). Consequently, measurements can be performed with good stability and sufficient accuracy.

[0092] In the above exemplary embodiment, two temperature sensors are provided at the upstream position and the downstream position on the ultrasonic wave propagation path, respectively. However, even by providing only one of the two temperature sensors, the temperature in the ultrasonic wave propagation path can be estimated.

[0093] Furthermore, temperature sensors can also be inserted into the ultrasonic wave propagation path, as long as the flow and ultrasonic wave propagation are barely affected.

[0094] Furthermore, in the exemplary embodiment described above, the pressure sensor is positioned so as to be directly inserted into the opening of the ultrasonic propagation path. Alternatively, the pressure sensor may be positioned away from the flow channel using a pressure connection path. Furthermore, in the exemplary embodiment described above, the pressure sensor is positioned so as to face the upper surface of the outermost layer of the multi-layer flow channel. Alternatively, the pressure sensor may be positioned on the side surface of the multi-layer flow channel, enabling pressure to be measured and averaged across multiple layers.

[0095] Furthermore, in the exemplary embodiment described above, the relative humidity sensor is provided at a downstream position on the ultrasonic wave propagation path. Alternatively, the relative humidity sensor may be provided away from the flow channel using a connecting path. Still alternatively, two relatively small, inexpensive relative humidity sensors may be provided at upstream and downstream positions on the ultrasonic wave propagation path, respectively, and their average value may be used.

[0096] [1-5. Assembly structure]

[0097] Figure 3 and Figure 4 Shown Figure 1 and Figure 2 The assembly structure of the hydrogen flow / concentration meter shown. Figure 3 1 is a perspective view showing the appearance of the flow channel portion 14 of the hydrogen flow / concentration meter 100 . Figure 4 is included Figure 3 An exploded perspective view of the entire hydrogen flow / concentration meter 100 is shown showing the flow channel portion 14 .

[0098] Figure 3 1 is a perspective view showing the appearance of the flow channel portion 14 equipped with the ultrasonic transducers 2 and 3, the temperature sensors 9 and 10, the pressure sensor 11, and the relative humidity sensor 13. The flow channel body 17 accommodates the following Figure 1 The measuring flow channel 1 is shown and includes an inlet connector 18 at the inlet end of the measuring flow channel 1 and an outlet connector 19 at the outlet end of the measuring flow channel 1 for pipe connection.

[0099] Figure 4 This is an exploded perspective view showing the components of the hydrogen flow / concentration meter 100. The flow channel body 17 houses the measurement flow channel 1. The upper portion of the flow channel body 17 is provided with mounting holes 20a, 20b, and 20c for inserting the temperature sensor 9, the pressure sensor 11, and the relative humidity sensor 13, respectively. Figure 4 The side surface shown on the front side in FIG is provided with not only a mounting hole 20d for inserting the ultrasonic transducer 3, but also a plurality of mounting portions 22 for mounting a control board 21, wherein the control board 21 is provided with a transceiver circuit 4a, a first signal processor 5a, and a second signal processor 5b. Figure 4Not shown, but the flow channel body 17 is Figure 4 Another side surface on the rear side of the device is provided with another mounting hole for inserting the ultrasonic transducer 2 .

[0100] The long side portion 32 of the rectangular control panel 21 is provided with a plurality of (for example, Figure 4 In the example shown, there are two) connecting terminals 31. A connecting terminal (not shown) provided at the end of a cable extending from an information processor (not shown) outside the hydrogen flow / concentration meter 100 can be inserted into each connecting terminal 31 to electrically connect the two connecting terminals to the information processor. In this case, the connecting terminals 31 are installed perpendicular to the long side and thickness of the control board 21. This can reduce the possibility of the control board 21 bending or warping due to the applied load when the connecting terminal is inserted into one of the connecting terminals 31 of the control board 21. If the control board 21 is repeatedly bent or warped, the control board 21 will crack. In contrast, according to this embodiment, installing the connecting terminals 31 to the control board 21 as described above can avoid causing cracks to the control board 21.

[0101] Furthermore, when the control board 21 is mounted on the flow channel body 17, the long side 33 of the lower portion of the control board 21 (i.e., the long side facing the long side on which the connection terminals 31 are provided) is positioned above the bottom surface 34 of the flow channel body 17. In other words, the long side 33 on the lower portion of the control board 21 is not flush with the bottom surface 34 of the flow channel body 17. Therefore, even if water collects near the bottom surface of the hydrogen flow / concentration meter 100, positioning the control board 21 above the bottom surface 34 of the flow channel body 17 prevents the electrical circuit of the control board 21 from being short-circuited by the collected water.

[0102] Note that the flow channel portion 14 is formed by airtightly mounting the ultrasonic transducers 2 and 3, the temperature sensors 9 and 10, the pressure sensor 11, and the relative humidity sensor 13 to the flow channel body 17 via the airtight sealing member 23. The entire device is then assembled by fixing the control board 21 to the mounting portion 22 with screws and attaching the housing 24 so as to cover the assembly of these components from above. Note that illustrations of cables connecting the ultrasonic transducers 2 and 3, the temperature sensors 9 and 10, the pressure sensor 11, and the relative humidity sensor 13 to the control board 21, as well as illustrations of cables connecting the connectors 27 and 28 to be connected to external devices to the control board 21, are omitted.

[0103] In this way, ultrasonic transducers 2 and 3, temperature sensors 9 and 10, pressure sensor 11, relative humidity sensor 13, and control board 21 are assembled onto flow channel main body 17 from its upper surface and both side surfaces, and then housing 24 is attached to the assembly of these components from above, thereby achieving a compact device. This configuration facilitates the assembly process and contributes to improved productivity.

[0104] In the exemplary embodiment of the present disclosure described above, the measurement channel 1 is configured as a multilayer channel. However, this is merely an example and should not be construed as limiting. Alternatively, the measurement channel 1 may have a single-layer structure, where the channel is not divided by any partition 7. Furthermore, the cross-sectional shape of the measurement channel 1 does not necessarily need to be rectangular, but may also be circular or substantially circular.

[0105] (Second embodiment)

[0106] [1-1. Structure]

[0107] The hydrogen flow / concentration meter 100 according to the second embodiment acquires some or all values ​​of the temperature, pressure, and humidity (relative humidity) of the mixed gas from the external device 4c, such as Figure 5 For example, the hydrogen flow / concentration meter 100 acquires temperature, pressure, and humidity as input values ​​provided by the external device 4c to the second signal processor 5b.

[0108] In the first embodiment, the temperature is obtained by measurement using temperature sensors 9 and 10. In the second embodiment, the temperature can be obtained from an external device 4c. If the temperature is already known by other means, it is not necessary to provide temperature sensors 9 and 10, and the input value provided by the external device 4c can be used as the measured value of the temperature.

[0109] In the first embodiment, the pressure is obtained by measurement using the pressure sensor 11. In the second embodiment, the pressure can be obtained from the external device 4c. If the pressure is already known by other means, the pressure sensor 11 is not necessarily provided, and the input value provided by the external device 4c can be used as the measured value of the pressure.

[0110] In the first embodiment, the humidity is obtained by measurement using the relative humidity sensor 13. In the second embodiment, the humidity can be obtained from the external device 4c. If the humidity is already known by other means, the relative humidity sensor 13 is not necessarily provided, and the input value provided by the external device 4c can be used as the measured value of the humidity.

[0111] In the hydrogen flow / concentration meter 100 according to the present embodiment, the second signal processor 5 b can acquire all values ​​indicating, for example, the temperature, pressure, and humidity of the mixed gas from the external device 4 c as measurement values.

[0112] Alternatively, in the hydrogen flow / concentration meter 100 according to this embodiment, the second signal processor 5b can use the sensor unit 4b to obtain at least one measurement value representing the temperature, pressure and humidity of the mixed gas, and obtain the value of at least one of the remaining temperature, pressure and humidity of the mixed gas from the external device 4c as the measurement value.

[0113] In the first example, the second signal processor 5b obtains a temperature measurement using the sensor unit 4b and obtains a pressure value and a humidity value from the external device 4c. In the second example, the second signal processor 5b obtains a pressure measurement using the sensor unit 4b and obtains a temperature value and a humidity value from the external device 4c. In the third example, the second signal processor 5b obtains a humidity measurement using the sensor unit 4b and obtains a temperature value and a pressure value from the external device 4c.

[0114] In the fourth example, the second signal processor 5b obtains the measured values ​​of temperature and pressure using the sensor unit 4b, and obtains the humidity value from the external device 4c. In the fifth example, the second signal processor 5b obtains the measured values ​​of temperature and humidity using the sensor unit 4b, and obtains the pressure value from the external device 4c. In the sixth example, the second signal processor 5b obtains the measured values ​​of pressure and humidity using the sensor unit 4b, and obtains the temperature value from the external device 4c.

[0115] Alternatively, the external device 4c may be configured to receive input of the temperature, pressure, and humidity values ​​of the mixed gas. For example, the external device 4c may include an input unit for receiving input of the temperature, pressure, and humidity values ​​of the mixed gas. In this case, the second signal processor 5b acquires the input values ​​provided by the external device 4c as the measured values.

[0116] [1-2. Method of measuring concentration]

[0117] The method for measuring concentration according to the present embodiment is the same as the method for measuring concentration according to the first embodiment, and therefore, a description thereof will be omitted here.

[0118] [1-3. Advantages]

[0119] The hydrogen flow / concentration meter 100 according to this embodiment, as well as the hydrogen flow / concentration meter 100 according to the first embodiment, can accurately measure the flow and concentration of hydrogen using the measured values ​​of temperature, pressure, and relative humidity, even when the measured gas is under high humidity conditions. Therefore, a highly practical hydrogen flow / concentration meter 100 is realized.

[0120] In the exemplary embodiment of the present disclosure described above, the measurement flow channel 1 is configured as a multi-layer flow channel. Alternatively, the measurement flow channel 1 may also have a single-layer structure, in which the flow channel is not divided by any partition 7. In addition, the cross-sectional shape of the measurement flow channel 1 does not necessarily have to be a rectangular cross-section, but may also be a circular cross-section or a substantially circular cross-section.

[0121] In the first and second embodiments of the present disclosure, a so-called "Z path" in which a pair of ultrasonic transducers 2 and 3 are arranged to form an inclined angle θ with respect to the measurement flow channel 1 is used as an ultrasonic wave propagation path. However, this configuration is merely an example and should not be construed as limiting.

[0122] Alternatively, a path involving reflection (such as a so-called "V path" formed by configuring a pair of ultrasonic transducers 2 and 3 so that ultrasonic waves pass through the flow of mixed gas twice in the measurement flow channel 1) can also be used as the ultrasonic wave propagation path.

[0123] In the first and second embodiments of the present disclosure described above, the mixed gas includes nitrogen as an additional component in addition to hydrogen. However, this configuration is merely an example and should not be construed as limiting. Optionally, the mixed gas may also include hydrocarbons (HC) such as methane, carbon dioxide, helium, and argon, rather than nitrogen alone, as gases other than hydrogen.

[0124] (aspect)

[0125] The above-described exemplary embodiments and modifications thereof are specific embodiments of the following aspects of the present disclosure.

[0126] According to the first aspect, the hydrogen flow / concentration meter (100) includes a measuring flow channel (1), a pair of ultrasonic transducers (2, 3), a transceiver circuit (4a), a first signal processor (5a), a sensor unit (4b), a second signal processor (5b) and an operation unit (30). A mixed gas including hydrogen and water vapor flows through the measuring flow channel (1). The pair of ultrasonic transducers (2, 3) are arranged in the measuring flow channel (1) in a manner that crosses the flow of the mixed gas. The transceiver circuit (4a) is a circuit for transmitting and receiving ultrasonic waves between the pair of ultrasonic transducers (2, 3). The first signal processor (5a) is a signal processor for processing the signal provided by the transceiver circuit (4a). The sensor unit (4b) is a sensor unit for measuring the temperature, pressure and humidity of the mixed gas. The second signal processor (5b) uses the sensor unit (4b) to obtain corresponding measurement values ​​of the temperature, pressure and humidity of the mixed gas. The operation unit (30) calculates the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between a pair of ultrasonic transducers (2, 3) obtained by the first signal processor (5a) but also the corresponding measured values ​​of temperature, pressure and humidity obtained by the second signal processor (5b).

[0127] The hydrogen flow / concentration meter (100) according to the first aspect calculates the flow rate and concentration of hydrogen included in the flow, thereby allowing the flow rate and concentration of hydrogen to be accurately measured using the temperature, pressure, and relative humidity measured thereby, even if the target gas being measured is under high humidity conditions. Thus, a hydrogen flow / concentration meter (100) with high practicality is realized.

[0128] According to the second aspect, a hydrogen flow / concentration meter (100) includes a measuring flow channel (1), a pair of ultrasonic transducers (2, 3), a transceiver circuit (4a), a first signal processor (5a), a sensor unit (4b), a second signal processor (5b) and an operation unit (30). A mixed gas including hydrogen and water vapor flows through the measuring flow channel (1). The pair of ultrasonic transducers (2, 3) are arranged in the measuring flow channel (1) in a manner that straddles the flow of the mixed gas. The transceiver circuit (4a) is a circuit for transmitting and receiving ultrasonic waves between the pair of ultrasonic transducers (2, 3). The first signal processor (5a) is a signal processor for processing signals provided by the transceiver circuit (4a). The second signal processor (5b) obtains corresponding measurement values ​​of the temperature, pressure and humidity of the mixed gas from an external device (4c). The operation unit (30) calculates the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between a pair of ultrasonic transducers (2, 3) obtained by the first signal processor (5a) but also the corresponding measured values ​​of temperature, pressure and humidity obtained by the second signal processor (5b).

[0129] The hydrogen flow / concentration meter (100) according to the second aspect calculates the flow rate and concentration of hydrogen included in the flow, thereby allowing the flow rate and concentration of hydrogen to be accurately measured using the temperature, pressure, and relative humidity measured thereby, even if the target gas being measured is under high humidity conditions. Thus, a hydrogen flow / concentration meter (100) with high practicality is realized.

[0130] According to the third aspect, a hydrogen flow / concentration meter (100) includes a measuring flow channel (1), a pair of ultrasonic transducers (2, 3), a transceiver circuit (4a), a first signal processor (5a), a sensor unit (4b), a second signal processor (5b), and an operation unit (30). A mixed gas including hydrogen and water vapor flows through the measuring flow channel (1). The pair of ultrasonic transducers (2, 3) are arranged in the measuring flow channel (1) in a manner that straddles the flow of the mixed gas. The transceiver circuit (4a) is a circuit for transmitting and receiving ultrasonic waves between the pair of ultrasonic transducers (2, 3). The first signal processor (5a) is a signal processor for processing a signal provided by the transceiver circuit (4a). The sensor unit (4b) is a sensor unit for measuring at least one of the temperature, pressure, and humidity of the mixed gas. The second signal processor (5b) obtains a measurement value of at least one of the temperature, pressure, and humidity of the mixed gas using the sensor unit (4b), and acquires values ​​of the remaining temperature, pressure, and humidity of the mixed gas other than the at least one from the external device (4c) as measurement values. The operation unit (30) calculates the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers (2, 3) obtained by the first signal processor (5a) but also the corresponding measurement values ​​of the temperature, pressure, and humidity obtained by the second signal processor (5b).

[0131] The hydrogen flow / concentration meter (100) according to the third aspect calculates the flow rate and concentration of hydrogen included in the flow, thereby allowing the flow rate and concentration of hydrogen to be accurately measured using the temperature, pressure, and relative humidity measured thereby, even if the target gas being measured is under high humidity conditions. Thus, a hydrogen flow / concentration meter (100) with high practicality is realized.

[0132] In the hydrogen flow / concentration meter (100) according to the fourth aspect, which can be implemented in combination with any one of the first to third aspects, the measurement flow channel (1) is constructed as a multi-layer flow channel (8) partitioned by at least one partition (7).

[0133] The hydrogen flow / concentration meter (100) according to the fourth aspect helps to rectify the flow and stabilize the turbulence, thereby reducing the variation of the measured physical quantities (i.e., temperature, pressure, and relative humidity). Therefore, the flow rate and concentration can be measured with good stability.

[0134] Industrial applicability

[0135] As can be seen from the foregoing description, even if the mixed gas including hydrogen is under high humidity conditions, the hydrogen flow / concentration meter according to the present disclosure can accurately measure the flow and concentration of hydrogen. Therefore, the hydrogen flow / concentration meter according to the present disclosure can be widely used as a measuring instrument, not only for controlling fuel cells and fuel cell vehicles in which such a situation occurs, but also for various other applications using fuel cells.

[0136] Description of Reference Numerals

[0137] 1. Measuring flow channel

[0138] 2.3 Ultrasonic transducer

[0139] 4a Transceiver loop

[0140] 4b Sensor unit

[0141] 4c External Devices

[0142] 5a First signal processor

[0143] 5b Second signal processor

[0144] 7 Dividers

[0145] 8 Multi-layer flow channel

[0146] 30 Arithmetic Units

[0147] 100 Hydrogen flow / concentration meter

Claims

1. A hydrogen flow / concentration meter, comprising: a measuring flow channel through which a mixed gas including hydrogen and water vapor flows; a pair of ultrasonic transducers disposed in the measurement flow channel in a manner straddling the flow of the mixed gas; a transceiver circuit configured to transmit and receive ultrasonic waves between the pair of ultrasonic transducers; a first signal processor configured to process a signal provided by the transceiver circuit; a sensor unit configured to measure temperature, pressure, and humidity of the mixed gas; a second signal processor configured to obtain respective measurement values ​​of the temperature, pressure, and humidity of the mixed gas using the sensor unit; and an arithmetic unit configured to calculate the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers obtained by the first signal processor but also the corresponding measured values ​​of the temperature, the pressure, and the humidity obtained by the second signal processor.

2. A hydrogen flow / concentration meter, comprising: a measuring flow channel through which a mixed gas including hydrogen and water vapor flows; a pair of ultrasonic transducers disposed in the measurement flow channel in a manner straddling the flow of the mixed gas; a transceiver circuit configured to transmit and receive ultrasonic waves between the pair of ultrasonic transducers; a first signal processor configured to process a signal provided by the transceiver circuit; a second signal processor configured to obtain respective measurement values ​​of the temperature, pressure, and humidity of the mixed gas from an external device; and an arithmetic unit configured to calculate the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers obtained by the first signal processor but also the corresponding measured values ​​of the temperature, the pressure, and the humidity obtained by the second signal processor.

3. A hydrogen flow / concentration meter, comprising: a measuring flow channel through which a mixed gas including hydrogen and water vapor flows; a pair of ultrasonic transducers disposed in the measurement flow channel in a manner straddling the flow of the mixed gas; a transceiver circuit configured to transmit and receive ultrasonic waves between the pair of ultrasonic transducers; a first signal processor configured to process a signal provided by the transceiver circuit; a sensor unit configured to measure at least one of temperature, pressure, and humidity of the mixed gas; a second signal processor configured to obtain a measurement value of the at least one of the temperature, pressure, and humidity of the mixed gas using the sensor unit, and acquire values ​​of the remaining ones of the temperature, pressure, and humidity of the mixed gas except the at least one from an external device as measurement values; as well as an arithmetic unit configured to calculate the flow rate and concentration of hydrogen in the mixed gas using not only the propagation time between the pair of ultrasonic transducers obtained by the first signal processor but also the corresponding measured values ​​of the temperature, the pressure, and the humidity obtained by the second signal processor.

4. The hydrogen flow / concentration meter according to any one of claims 1 to 3, wherein The measuring flow channel is constructed as a multi-layer flow channel divided by at least one partition.

Images