WO2014148081A1 - 超音波流量計、流体速度測定方法、および流体速度測定プログラム - Google Patents
超音波流量計、流体速度測定方法、および流体速度測定プログラム Download PDFInfo
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- WO2014148081A1 WO2014148081A1 PCT/JP2014/050933 JP2014050933W WO2014148081A1 WO 2014148081 A1 WO2014148081 A1 WO 2014148081A1 JP 2014050933 W JP2014050933 W JP 2014050933W WO 2014148081 A1 WO2014148081 A1 WO 2014148081A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
- G01F1/668—Compensating or correcting for variations in velocity of sound
Definitions
- Some embodiments according to the present invention relate to an ultrasonic flowmeter, a fluid velocity measuring method, and a fluid velocity measuring program for measuring the velocity of a fluid flowing through a pipe using ultrasonic waves.
- this ultrasonic flowmeter has a problem that the velocity of the fluid cannot be accurately measured when the velocity of the fluid flowing inside the piping includes a component perpendicular to the axial direction of the piping.
- An ultrasonic flowmeter and a fluid velocity measurement capable of accurately measuring the velocity of a fluid without interference of an ultrasonic transmission / reception unit.
- One object is to provide a method and a fluid velocity measurement program.
- An ultrasonic flowmeter is provided in a pipe through which a fluid flows, and includes a first ultrasonic transmission / reception unit that transmits and receives ultrasonic waves, and a downstream side of the first ultrasonic transmission / reception unit.
- a second ultrasonic transmission / reception unit that is provided in the pipe and transmits and receives ultrasonic waves, and a main body unit that measures the fluid velocity, and includes the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit.
- the ultrasonic transmission / reception unit is disposed with the fluid interposed therebetween, and the main body has a first fluid propagation path that traverses the inside of the piping in the radial direction 2n-1 times (n is a positive integer),
- a first propagation time difference which is a difference between a time during which an ultrasonic wave transmitted from the two ultrasonic transmission / reception units propagates and a time during which an ultrasonic wave transmitted from the first ultrasonic transmission / reception unit propagates;
- Second fluid propagation path traversing the inside 2m-1 times in the radial direction (m is a positive integer other than n)
- To the second propagation time difference which is the difference between the time during which the ultrasonic wave transmitted from the second ultrasonic wave transmitting / receiving unit propagates and the time during which the ultrasonic wave transmitted from the first ultrasonic wave transmitting / receiving unit propagates. Based on this, the component parallel to the axis of the pipe at the fluid velocity is calculated.
- the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are arranged with the fluid flowing inside the pipe interposed therebetween, and the main body part extends 2n-1 times in the radial direction inside the pipe.
- N is a positive integer
- the time that the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates and the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit propagate through the first fluid propagation path that crosses A first propagation time difference that is a difference between the first ultrasonic wave and a second fluid propagation path that traverses the inside of the pipe 2m-1 times (m is a positive integer other than n) in the radial direction.
- the second propagation time difference which is the difference between the time during which the ultrasonic wave transmitted from the transmission / reception unit propagates and the time during which the ultrasonic wave transmitted from the first ultrasonic wave transmission / reception unit propagates.
- the ultrasonic wave is downstream in the fluid propagation path that traverses the inside of the pipe 2 (nm) times in the radial direction, that is, even times. It is possible to obtain the propagation time difference between the time for propagation from the upstream side to the upstream side and the time for the ultrasonic wave to propagate from the upstream side to the downstream side.
- the component parallel to the pipe axis in the fluid velocity is expressed using a known value before measuring the fluid velocity and the propagation time difference when traversing the inside of the pipe in the radial direction an even number of times. . Therefore, even when the fluid flow has an angle with respect to the axis of the pipe and the velocity of the fluid includes a component perpendicular to the axis of the pipe, the main body portion has a difference between the first propagation time difference and the second propagation time difference. Based on this, the component parallel to the axis of the pipe at the fluid velocity can be accurately calculated.
- the component parallel to the pipe axis at the fluid velocity is calculated based on the first propagation time difference and the second propagation time difference, the influence of the component perpendicular to the pipe axis at the fluid velocity is suppressed. Therefore, it is not necessary to arrange a long straight pipe on the upstream side.
- the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are arranged with the fluid flowing inside the pipe interposed therebetween. Therefore, even if the dimension (length of the axial direction of piping) of the 1st ultrasonic transmission / reception part and the 2nd ultrasonic transmission / reception part becomes large, it interferes with each other and does not become a hindrance (prevention) of installation.
- first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are arranged with the fluid flowing in the pipe interposed therebetween, whereby the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are piped.
- first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are piped.
- each of the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit includes an ultrasonic sensor installed on the outer periphery of the pipe.
- the first ultrasonic transmission / reception unit includes the ultrasonic sensor installed on the outer periphery of the pipe
- the second ultrasonic transmission / reception unit includes the ultrasonic sensor installed on the outer periphery of the pipe.
- each of the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit includes two ultrasonic sensors installed on the outer periphery of the pipe.
- the first ultrasonic transmission / reception unit 20 includes two ultrasonic sensors installed on the outer periphery of the pipe
- the second ultrasonic transmission / reception unit includes two ultrasonic sensors installed on the outer periphery of the pipe.
- the first ultrasonic transmission / reception unit includes two ultrasonic sensors and the second ultrasonic transmission / reception unit includes two ultrasonic sensors, for example, one ultrasonic sensor of the first ultrasonic transmission / reception unit
- the first propagation time difference is measured using one ultrasonic sensor of the second ultrasonic transmission / reception unit, and the other ultrasonic sensor of the first ultrasonic transmission / reception unit and the other of the second ultrasonic transmission / reception unit are measured. It is possible to measure the second propagation time difference using the ultrasonic sensor.
- the first fluid propagation path is a path that traverses the inside of the pipe in the radial direction three times
- the second fluid propagation path is a path that traverses the inside of the pipe in the radial direction once. is there.
- the first fluid propagation path is a path that traverses the inside of the pipe three times in the radial direction
- the second fluid propagation path is a path that traverses the inside of the pipe once in the radial direction.
- the first fluid propagation path is a path that traverses the inside of the pipe in the radial direction five times
- the second fluid propagation path is a path that traverses the inside of the pipe in the radial direction three times. is there.
- the first fluid propagation path is a path that traverses the inside of the pipe five times in the radial direction
- the second fluid propagation path is a path that traverses the inside of the pipe three times in the radial direction.
- the first fluid propagation path is a path that traverses the inside of the pipe in the radial direction seven times
- the second fluid propagation path is a path that traverses the inside of the pipe in the radial direction five times. is there.
- the first fluid propagation path is a path that traverses the inside of the pipe seven times in the radial direction
- the second fluid propagation path is a path that traverses the inside of the pipe five times in the radial direction.
- a first ultrasonic transmission / reception unit that is provided in a pipe through which a fluid flows and that transmits and receives ultrasonic waves, and downstream of the first ultrasonic transmission / reception unit.
- a second ultrasonic transmission / reception unit that transmits and receives ultrasonic waves and a main body unit that measures the speed of the fluid, and includes the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit.
- the ultrasonic transmission / reception unit is a fluid velocity measurement method used by the ultrasonic flowmeter disposed with the fluid interposed therebetween, and the inside of the piping is radially 2n-1 times (n is a positive integer) This is the difference between the time during which the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates and the time during which the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit propagates through the traversing first fluid propagation path.
- the first propagation time difference and the inside of the aforementioned pipe 2m-1 times in the radial direction (m is The time when the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates and the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit propagate through the second fluid propagation path that traverses Calculating a component parallel to the axis of the pipe at the fluid velocity based on the second propagation time difference which is a difference from the time.
- the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates through the first fluid propagation path that traverses the inside of the pipe in the radial direction 2n-1 times (n is a positive integer).
- the first propagation time difference which is the difference between the time and the propagation time of the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit, and the inside of the pipe in the radial direction 2m-1 times (m is a positive value other than n) Integer)
- the difference between the time during which the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates and the time during which the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit propagates through the traversing second fluid propagation path And calculating a component parallel to the axis of the pipe at the fluid velocity based on the second propagation time difference.
- the ultrasonic wave is downstream in the fluid propagation path that traverses the inside of the pipe 2 (nm) times in the radial direction, that is, even times. It is possible to obtain the propagation time difference between the time for propagation from the upstream side to the upstream side and the time for the ultrasonic wave to propagate from the upstream side to the downstream side.
- the component parallel to the pipe axis in the fluid velocity is expressed using a known value before measuring the fluid velocity and the propagation time difference when traversing the inside of the pipe in the radial direction an even number of times. .
- the main body portion has a difference between the first propagation time difference and the second propagation time difference. Based on this, the component parallel to the axis of the pipe at the fluid velocity can be accurately calculated.
- the component parallel to the pipe axis at the fluid velocity is calculated based on the first propagation time difference and the second propagation time difference, the influence of the component perpendicular to the pipe axis at the fluid velocity is suppressed. Therefore, it is not necessary to arrange a long straight pipe on the upstream side.
- the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are arranged with the fluid flowing inside the pipe interposed therebetween. Therefore, even if the dimension (length of the axial direction of piping) of the 1st ultrasonic transmission / reception part and the 2nd ultrasonic transmission / reception part becomes large, it interferes with each other and does not become a hindrance (prevention) of installation.
- first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are arranged with the fluid flowing in the pipe interposed therebetween, whereby the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are piped.
- first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are piped.
- a first ultrasonic transmission / reception unit that is provided in a pipe through which a fluid flows and that transmits and receives ultrasonic waves, and downstream of the first ultrasonic transmission / reception unit.
- a second ultrasonic transmission / reception unit that transmits and receives ultrasonic waves and a main body unit that measures the speed of the fluid, and includes the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit.
- the ultrasonic transmission / reception unit is a fluid velocity measurement program executed by the ultrasonic flowmeter arranged with the fluid interposed therebetween, and the inside of the pipe is radially 2n-1 times (n is a positive integer) This is the difference between the time during which the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates and the time during which the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit propagates through the traversing first fluid propagation path.
- the first propagation time difference and the inside of the aforementioned pipe are 2 m in the radial direction
- the time that the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates through the second fluid propagation path traversing once (m is a positive integer other than n) is transmitted from the first ultrasonic transmission / reception unit.
- calculating a component parallel to the pipe axis at the fluid velocity based on the second propagation time difference, which is a difference from the propagation time of the ultrasonic wave.
- the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates through the first fluid propagation path that traverses the inside of the pipe in the radial direction 2n-1 times (n is a positive integer).
- the first propagation time difference which is the difference between the time and the propagation time of the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit, and the inside of the pipe in the radial direction 2m-1 times (m is a positive value other than n) Integer)
- the difference between the time during which the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit propagates and the time during which the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit propagates through the traversing second fluid propagation path And calculating a component parallel to the axis of the pipe at the fluid velocity based on the second propagation time difference.
- the ultrasonic wave is downstream in the fluid propagation path that traverses the inside of the pipe 2 (nm) times in the radial direction, that is, even times. It is possible to obtain the propagation time difference between the time for propagation from the upstream side to the upstream side and the time for the ultrasonic wave to propagate from the upstream side to the downstream side.
- the component parallel to the pipe axis in the fluid velocity is expressed using a known value before measuring the fluid velocity and the propagation time difference when traversing the inside of the pipe in the radial direction an even number of times. .
- the main body portion has a difference between the first propagation time difference and the second propagation time difference. Based on this, the component parallel to the axis of the pipe at the fluid velocity can be accurately calculated.
- the component parallel to the pipe axis at the fluid velocity is calculated based on the first propagation time difference and the second propagation time difference, the influence of the component perpendicular to the pipe axis at the fluid velocity is suppressed. Therefore, it is not necessary to arrange a long straight pipe on the upstream side.
- the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are arranged with the fluid flowing inside the pipe interposed therebetween. Therefore, even if the dimension (length of the axial direction of piping) of the 1st ultrasonic transmission / reception part and the 2nd ultrasonic transmission / reception part becomes large, it interferes with each other and does not become a hindrance (prevention) of installation.
- first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are arranged with the fluid flowing in the pipe interposed therebetween, whereby the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are piped.
- first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit are piped.
- the main body portion has the first propagation even when the fluid flow has an angle with respect to the axis of the pipe and the velocity of the fluid includes a component perpendicular to the axis of the pipe. Based on the time difference and the second propagation time difference, the component parallel to the pipe axis at the fluid velocity can be accurately calculated. Therefore, the ultrasonic flowmeter can accurately measure the flow rate of the fluid based on the component parallel to the axis of the pipe at the fluid velocity.
- the ultrasonic flowmeter can relax the restriction (limitation) of the installation position, and can be installed at any place, for example, immediately after a bent pipe.
- the ultrasonic flowmeter can easily expand the measurable flow velocity range by increasing the dimensions (length in the axial direction of the pipe) of the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit. .
- the ultrasonic flow meter can improve the SN ratio.
- the main body portion has the first propagation even when the fluid flow has an angle with respect to the axis of the pipe and the fluid velocity includes a component perpendicular to the axis of the pipe. Based on the time difference and the second propagation time difference, the component parallel to the pipe axis at the fluid velocity can be accurately calculated. Therefore, the ultrasonic flowmeter can accurately measure the flow rate of the fluid based on the component parallel to the axis of the pipe at the fluid velocity.
- the ultrasonic flowmeter can relax the restriction (limitation) of the installation position, and can be installed at any place, for example, immediately after a bent pipe.
- the ultrasonic flowmeter can easily expand the measurable flow velocity range by increasing the dimensions (length in the axial direction of the pipe) of the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit. .
- the ultrasonic flow meter can improve the SN ratio.
- the main body portion has the first propagation even when the fluid flow has an angle with respect to the axis of the pipe and the fluid velocity includes a component perpendicular to the axis of the pipe. Based on the time difference and the second propagation time difference, the component parallel to the pipe axis at the fluid velocity can be accurately calculated. Therefore, the ultrasonic flowmeter can accurately measure the flow rate of the fluid based on the component parallel to the axis of the pipe at the fluid velocity.
- the ultrasonic flowmeter can relax the restriction (limitation) of the installation position, and can be installed at any place, for example, immediately after a bent pipe.
- the ultrasonic flowmeter can easily expand the measurable flow velocity range by increasing the dimensions (length in the axial direction of the pipe) of the first ultrasonic transmission / reception unit and the second ultrasonic transmission / reception unit. .
- the ultrasonic flow meter can improve the SN ratio.
- FIG. 1 It is a block diagram which shows schematic structure of the ultrasonic flowmeter in 1st Embodiment. It is an expanded sectional view explaining the structure of the 1st ultrasonic sensor shown in FIG. It is a sectional side view for demonstrating the calculation method of the speed of the fluid which flows through the inside of piping in the direction parallel to the axis
- FIG. 1 is a configuration diagram illustrating a schematic configuration of an ultrasonic flowmeter 100 according to the first embodiment.
- the ultrasonic flowmeter 100 is for measuring the flow velocity of a fluid, for example, a gas (gas) or a liquid flowing inside the pipe A.
- the pipe A is, for example, a metal pipe such as stainless steel (SUS) or a resin pipe (tubular body) such as plastic.
- the pipe A is arranged so that the axis (longitudinal direction) of the pipe A is the left-right direction in FIG.
- the ultrasonic flowmeter 100 includes a first ultrasonic transmission / reception unit 20, a second ultrasonic transmission / reception unit 30, and a main body unit 50.
- Each of the first ultrasonic transmission / reception unit 20 and the second ultrasonic transmission / reception unit 30 is for transmitting and receiving ultrasonic waves.
- the first ultrasonic transmission / reception unit 20 is provided at a predetermined position of the pipe A
- the second ultrasonic transmission / reception unit 30 is provided in the pipe A on the downstream side (right side in FIG. 1) with respect to the first ultrasonic transmission / reception unit 20.
- the first ultrasonic transmission / reception unit 20 is provided in the pipe A on the upstream side (left side in FIG. 1) with respect to the second ultrasonic transmission / reception unit 30.
- the first ultrasonic transmission / reception unit 20 and the second ultrasonic transmission / reception unit 30 are disposed to face each other with the fluid flowing in the pipe A interposed therebetween.
- the first ultrasonic transmission / reception unit 20 disposed on the upstream side of the pipe A includes, for example, a first ultrasonic sensor 20A installed on the outer periphery of the pipe A.
- positioned under the piping A is provided with the 2nd ultrasonic sensor 30A installed in the outer periphery of the piping A, for example.
- the first ultrasonic sensor 20A and the second ultrasonic sensor 30A transmit and receive ultrasonic waves to each other. That is, the ultrasonic wave transmitted by the first ultrasonic sensor 20A is received by the second ultrasonic sensor 30A, and the ultrasonic wave transmitted by the second ultrasonic sensor 30A is received by the first ultrasonic sensor 20A.
- FIG. 2 is an enlarged cross-sectional view for explaining the configuration of the first ultrasonic sensor 20A shown in FIG. As shown in FIG. 2, the first ultrasonic sensor 20 ⁇ / b> A includes a wedge 21 and an ultrasonic transmitter / receiver 22.
- the wedge 21 is for allowing ultrasonic waves to enter the pipe A at a predetermined acute angle, and is, for example, a resin or metal member.
- the wedge 21 is installed such that the bottom surface 21 a contacts the outer peripheral surface of the pipe A. Further, the wedge 21 is formed with a slope 21b having a predetermined angle with respect to the bottom surface 21a.
- An ultrasonic transmitter / receiver 22 is installed on the slope 21b.
- a contact medium may be interposed between the bottom surface 21 a and the outer peripheral surface of the pipe A.
- the ultrasonic transmitter / receiver 22 is for transmitting ultrasonic waves and receiving ultrasonic waves.
- the ultrasonic transmitter / receiver 22 can be composed of, for example, a piezoelectric element.
- a lead wire (not shown) is electrically connected to the ultrasonic transceiver 22.
- the ultrasonic transmitter / receiver 22 vibrates at the predetermined frequency and emits an ultrasonic wave.
- an ultrasonic wave is transmitted from the ultrasonic transceiver 22.
- the ultrasonic wave transmitted with the dimensions (length and width) of the ultrasonic transmitter / receiver 22 propagates through the wedge 21 at an angle of the inclined surface 21b.
- the ultrasonic wave propagating through the wedge 21 is refracted at the interface between the wedge 21 and the outer wall of the pipe A to change the incident angle, and is further refracted and incident at the interface between the inner wall of the pipe A and the fluid flowing through the pipe A.
- the angle changes and propagates through the fluid. Since the refraction at the interface follows Snell's law, the wedge 21 is set by setting the angle of the inclined surface 21b in advance based on the ultrasonic velocity when propagating through the pipe A and the ultrasonic velocity when propagating through the fluid. Can make the ultrasonic wave incident on the fluid flowing in the pipe A at a desired angle.
- the ultrasonic transmitter / receiver 22 vibrates at the frequency of the ultrasonic wave to generate an electric signal. Thereby, the ultrasonic wave is received by the ultrasonic wave transmitter / receiver 22. An electric signal generated in the ultrasonic transmitter / receiver 22 is detected by a main body 50 described later via a lead wire.
- the second ultrasonic sensor 30A has the same configuration as the first ultrasonic sensor 20A. That is, the second ultrasonic sensor 30 ⁇ / b> A also includes the wedge 21 and the ultrasonic transmitter / receiver 22. Therefore, the detailed description of the second ultrasonic sensor 30A is omitted with the description of the first ultrasonic sensor 20A described above.
- the main body 50 shown in FIG. 1 is for measuring the velocity of the fluid flowing inside the pipe A.
- the main body unit 50 includes a switching unit 51, a transmission circuit unit 52, a reception circuit unit 53, a timer unit 54, a calculation control unit 55, and an input / output unit 56.
- the switching unit 51 is for switching between transmission and reception of ultrasonic waves.
- the switching unit 51 is connected to the first ultrasonic sensor 20A and the second ultrasonic sensor 30A.
- the switching unit 51 can be configured to include, for example, a changeover switch.
- the switching unit 51 switches the changeover switch based on the control signal input from the arithmetic control unit 55, connects one of the first ultrasonic sensor 20A and the second ultrasonic sensor 30A to the transmission circuit unit 52, and The other of the first ultrasonic sensor 20 ⁇ / b> A and the second ultrasonic sensor 30 ⁇ / b> A is connected to the receiving circuit unit 53.
- one of the first ultrasonic sensor 20A and the second ultrasonic sensor 30A transmits an ultrasonic wave
- the other of the first ultrasonic sensor 20A and the second ultrasonic sensor 30A receives the ultrasonic wave. can do.
- the transmission circuit unit 52 is for causing the first ultrasonic sensor 20A and the second ultrasonic sensor 30A to transmit ultrasonic waves.
- the transmission circuit unit 52 can be configured to include, for example, an oscillation circuit that generates a rectangular wave having a predetermined frequency, a drive circuit that drives the first ultrasonic sensor 20A, and the second ultrasonic sensor 30A.
- the transmission circuit unit 52 uses the rectangular wave generated by the oscillation circuit as a drive signal based on the control signal, of the first ultrasonic sensor 20A and the second ultrasonic sensor 30A.
- To one of the ultrasonic transceivers 22 Thereby, one ultrasonic transmitter / receiver 22 of the first ultrasonic sensor 20A and the second ultrasonic sensor 30A is driven, and the ultrasonic transmitter / receiver 22 transmits ultrasonic waves.
- ultrasonic waves mean sound waves in a frequency band of 20 [kHz] or higher. Therefore, the ultrasonic wave transmitted by the ultrasonic transceiver 22 is a sound wave having a frequency band of 20 [kHz] or higher. Preferably, the ultrasonic wave transmitted by the ultrasonic transceiver 22 is an ultrasonic wave having a frequency band of 100 [kHz] or more and 2.0 [MHz] or less. In any case, the ultrasonic wave transmitted by the ultrasonic transceiver 22 of the first ultrasonic sensor 20A and the ultrasonic wave transmitted by the ultrasonic transceiver 22 of the second ultrasonic sensor 30A have the same frequency. It may be a different frequency.
- the receiving circuit unit 53 is for detecting the ultrasonic waves received by the first ultrasonic sensor 20A and the second ultrasonic sensor 30A.
- the receiving circuit unit 53 can include, for example, an amplifier circuit that amplifies a signal with a predetermined gain (gain), a filter circuit that extracts an electric signal with a predetermined frequency, and the like.
- gain a predetermined gain
- filter circuit that extracts an electric signal with a predetermined frequency
- the reception circuit unit 53 Based on the control signal input from the arithmetic control unit 55, the reception circuit unit 53 receives the electrical signal output from one ultrasonic transmitter / receiver 22 of the first ultrasonic sensor 20A and the second ultrasonic sensor 30A. Amplify, filter and convert to received signal.
- the reception circuit unit 53 outputs the converted reception signal to the calculation control unit 55.
- the timer 54 is for measuring time in a predetermined period.
- the timer unit 54 can be constituted by, for example, an oscillation circuit. Note that the oscillation circuit may be shared with the transmission circuit unit 52.
- the timer 54 measures the time by counting the number of reference waves of the oscillation circuit based on the start signal and stop signal input from the arithmetic control unit 55.
- the time measuring unit 54 outputs the measured time to the calculation control unit 55.
- the calculation control unit 55 is for calculating the flow rate of the fluid flowing through the pipe A by calculation.
- the arithmetic control unit 55 can be configured by, for example, a CPU, a memory such as a ROM or a RAM, an input / output interface, or the like.
- the arithmetic control unit 55 controls each part of the main body unit 50 such as the switching unit 51, the transmission circuit unit 52, the reception circuit unit 53, the time measuring unit 54, and the input / output unit 56.
- the input / output unit 56 is for a user (user) to input information and to output information to the user.
- the input / output unit 56 can be configured by, for example, input means such as operation buttons, output means such as a display display, and the like.
- input means such as operation buttons
- output means such as a display display
- various types of information such as settings are input to the arithmetic control unit 55 via the input / output unit 56.
- the input / output unit 56 displays information such as the fluid flow rate, the fluid velocity, the accumulated flow rate during a predetermined period, and the like calculated by the arithmetic control unit 55 on a display display.
- the direction parallel to the axis of the pipe A is the x-axis (or the x-axis direction) and is perpendicular to the x-axis unless otherwise specified.
- a direction parallel to the diameter of the pipe A will be described as a y-axis (or y-axis direction), and a direction perpendicular to the x-axis and the y-axis will be described as a z-axis (or z-axis direction).
- the velocity of the fluid is V [m / s]
- C [m / s] is the sound velocity
- L [m] is the propagation path length of the ultrasonic wave propagating the fluid
- the angle between and is described as ⁇ .
- FIG. 3 is a side sectional view for explaining a method of calculating the velocity of the fluid flowing in the pipe A in the direction parallel to the axis of the pipe A.
- the fluid flows in the pipe A at a velocity V along the x-axis direction.
- the first ultrasonic sensor 20A installed on the upstream side of the pipe A (left side in FIG. 3) transmits ultrasonic waves
- the second ultrasonic wave installed on the downstream side of the pipe A (right side in FIG. 3).
- t 1d L / (C + V cos ⁇ ) (1)
- ⁇ t 1 2LV cos ⁇ / (C 2 ⁇ V 2 cos ⁇ 2 ) (3)
- the speed of sound C is, for example, about 1500 [m / s] when the fluid is water (liquid) and about 343 [m / s] when the fluid is air (gas).
- the velocity V of the fluid measured by the ultrasonic flowmeter 100 is about 30 [m / s] at the maximum.
- the value V 2 cos ⁇ 2 is extremely small as compared to the square of the sound speed C, so it may be omitted.
- the propagation time difference ⁇ t 1 can be expressed as the following equation (4).
- ⁇ t 1 2LV cos ⁇ / C 2 (4)
- V C 2 ⁇ ⁇ t 1 / 2L cos ⁇ (5)
- the sound velocity C, the propagation path length L, and the angle ⁇ are known values before the fluid velocity is measured. Therefore, by measuring the propagation time difference ⁇ t 1 , the fluid velocity V can be calculated by the equation (5). It can be calculated from 5).
- the flow rate Q [m 3 / s] of the fluid flowing inside the pipe A is calculated using the correction coefficient K, the cross-sectional area S [m 2 ] of the pipe A, and the fluid velocity V [m / s]. It is represented by the following formula (6).
- Q KSV (6)
- the arithmetic control unit 55 calculates the inside of the pipe A from the equation (6) based on the fluid velocity V calculated by the equation (5). It is possible to calculate the flow rate Q of the fluid flowing through the.
- FIG. 4 is a side sectional view for explaining a method of calculating the velocity of the fluid flowing through the inside of the pipe A at an angle with respect to the axis of the pipe A.
- the fluid flows at an angle ⁇ with respect to the axis (x-axis) of the pipe A
- the fluid velocity V is a direction (y-axis) perpendicular to the axis (x-axis) of the pipe A.
- Direction component.
- the first ultrasonic sensor 20A installed on the upstream side (left side in FIG. 4) of the pipe A transmits ultrasonic waves
- the second ultrasonic wave installed on the downstream side (right side in FIG. 4) of the pipe A.
- T 1d L / ⁇ C + Vcos ( ⁇ + ⁇ ) ⁇ (11)
- T 1u L / ⁇ C ⁇ Vcos ( ⁇ + ⁇ ) ⁇ (12)
- Equation (15) the propagation path length L and the angle ⁇ are known values before the fluid velocity is measured, while the angle ⁇ is not known before the fluid velocity is measured. Also, it is difficult to measure the angle ⁇ during the fluid velocity measurement. Further, even when the fluid has a slight angle ⁇ , it is difficult to calculate the fluid velocity V from the equation (15) because the angle ⁇ has a great influence on the flow velocity in the equation (15).
- a sufficiently long straight pipe is arranged further upstream (left side in FIG. 4) of the first ultrasonic sensor 20A, and the angle ⁇ is reduced in the fluid flowing in the pipe A.
- the fluid flows in a direction parallel to the axial direction of the pipe A.
- FIG. 5 is a flowchart for explaining an example of the operation in which the ultrasonic flowmeter 100 shown in FIG. 1 measures the velocity of the fluid flowing in the pipe A.
- the arithmetic control unit 55 reads a program stored in a ROM or the like, and executes a fluid velocity measurement process S200 shown in FIG.
- the calculation control unit 55 determines whether or not a predetermined set value is set (S201). The calculation control unit 55 repeats the step of S201 until a predetermined set value is set.
- the predetermined set value includes, for example, the sound velocity C, the propagation path length L, the angle ⁇ , the correction coefficient K, the cross-sectional area S of the pipe A, and the like.
- the user inputs information on the pipe A, fluid information, and the like via the input / output unit 56 before measuring the fluid velocity.
- the arithmetic control unit 55 reads a corresponding predetermined setting value or calculates a predetermined setting value, and stores the predetermined setting value in a nonvolatile memory or the like.
- the arithmetic control unit 55 can determine the step of S201 by accessing the memory.
- the arithmetic control unit 55 displays a message or the like prompting the user (user) to input information on the output unit such as a display display through the input / output unit 56 while repeating the step of S201. You may do it.
- the arithmetic control unit 55 determines the first fluid propagation path that traverses the inside of the pipe A in the radial direction 2n-1 times (n is a positive integer).
- the propagation time of the ultrasonic wave transmitted from the first ultrasonic sensor 20A of the first ultrasonic wave transmitting / receiving unit 20 and the ultrasonic wave transmitted from the second ultrasonic sensor 30A of the second ultrasonic wave transmitting / receiving unit 30 propagate.
- a first propagation time difference which is a difference from time, is measured (S202).
- the calculation control unit 55 outputs a control signal to the switching unit 51, for example, connects the first ultrasonic sensor 20A to the transmission circuit unit 52, and connects the second ultrasonic sensor 30A to the reception circuit. Connected to the unit 53.
- the arithmetic control unit 55 outputs a control signal to the transmission circuit unit 52 to transmit ultrasonic waves from the first ultrasonic sensor 20 ⁇ / b> A, and outputs a start signal to the time measuring unit 54.
- the arithmetic control unit 55 outputs a stop signal to the time measuring unit 54 based on the reception signal input from the reception circuit unit 53, and the ultrasonic wave propagates through the first fluid propagation path from the upstream side to the downstream side. Measure the propagation time.
- the arithmetic control unit 55 outputs a control signal to the switching unit 51, for example, connects the second ultrasonic sensor 30 ⁇ / b> A to the transmission circuit unit 52 and connects the first ultrasonic sensor 20 ⁇ / b> A to the reception circuit unit 53. Let Then, the arithmetic control unit 55 outputs a control signal to the transmission circuit unit 52 to transmit ultrasonic waves from the second ultrasonic sensor 30 ⁇ / b> A, and outputs a start signal to the time measuring unit 54.
- the arithmetic control unit 55 outputs a stop signal to the time measuring unit 54 based on the received signal input from the receiving circuit unit 53, and the ultrasonic wave propagates through the first fluid propagation path from the downstream side to the upstream side. Measure the propagation time.
- the arithmetic control unit 55 determines the first propagation time difference from the propagation time for propagating the first fluid propagation path from the upstream side to the downstream side and the propagation time for propagating the first fluid propagation path from the downstream side to the upstream side. Ask for.
- FIG. 6 is a side sectional view for explaining an example of measurement of the first propagation time difference of the first fluid propagation path.
- the arithmetic control unit 55 performs the first supersonic wave transmission / reception unit 20 on the second fluid propagation path traversing 2m ⁇ 1 times (m is a positive integer other than n).
- a second propagation time difference that is a difference between a time during which the ultrasonic wave transmitted from the acoustic wave sensor 20A propagates and a time during which the ultrasonic wave transmitted from the second ultrasonic sensor 30A of the second ultrasonic wave transmitting / receiving unit 30 propagates is measured. (S203).
- the calculation control unit 55 outputs a control signal to the switching unit 51, for example, connects the first ultrasonic sensor 20A to the transmission circuit unit 52, and connects the second ultrasonic sensor 30A to the reception circuit. Connected to the unit 53.
- the arithmetic control unit 55 outputs a control signal to the transmission circuit unit 52 to transmit ultrasonic waves from the first ultrasonic sensor 20 ⁇ / b> A, and outputs a start signal to the time measuring unit 54.
- the arithmetic control unit 55 outputs a stop signal to the time measuring unit 54 based on the received signal input from the receiving circuit unit 53, and the ultrasonic wave propagates through the second fluid propagation path from the upstream side to the downstream side. Measure the propagation time.
- the arithmetic control unit 55 outputs a control signal to the switching unit 51, for example, connects the second ultrasonic sensor 30 ⁇ / b> A to the transmission circuit unit 52 and connects the first ultrasonic sensor 20 ⁇ / b> A to the reception circuit unit 53. Let Then, the arithmetic control unit 55 outputs a control signal to the transmission circuit unit 52 to transmit ultrasonic waves from the second ultrasonic sensor 30 ⁇ / b> A, and outputs a start signal to the time measuring unit 54.
- the arithmetic control unit 55 outputs a stop signal to the time measuring unit 54 based on the received signal input from the receiving circuit unit 53, and the ultrasonic wave propagates through the second fluid propagation path from the downstream side to the upstream side. Measure the propagation time.
- the arithmetic control unit 55 determines the second propagation time difference from the propagation time for propagating the second fluid propagation path from the upstream side to the downstream side and the propagation time for propagating the second fluid propagation path from the downstream side to the upstream side. Ask for.
- FIG. 7 is a side sectional view for explaining an example of measurement of the second propagation time difference of the second fluid propagation path.
- the arithmetic control unit 55 calculates the difference between the first propagation time difference measured in S202 and the second propagation time difference measured in S203 (S204).
- the difference calculated in S204 is that the ultrasonic wave propagates from the downstream side to the upstream side in a path traversing the inside of the pipe A in the radial direction 2 (nm) times (m ⁇ n), that is, an even number of times. This is equivalent to the time difference between the time for the ultrasonic wave to propagate from the upstream side to the downstream side.
- FIG. 8 is a side sectional view for explaining an example of calculation of the difference between the first propagation time difference and the second propagation time difference.
- the first fluid propagation path is a path that traverses (crosses) the inside of the pipe A three times in the radial direction
- the second fluid propagation path is the pipe.
- the path of the difference between the first fluid propagation path and the second fluid propagation path is as shown by a solid line inside the pipe A in FIG. This is a path traversing (traversing) the inside of the pipe A twice in the radial direction.
- a route that traverses the pipe A in the radial direction twice (crosses) will be divided into two.
- the upstream side of the pipe A (in FIG.
- the propagation time T 21d for propagation of the ultrasonic wave transmitted from the first ultrasonic sensor 20A installed on the left side is as follows when the fluid flows at an angle ⁇ with respect to the axis of the pipe A: It is represented by Formula (21).
- T 21d L / ⁇ C + V cos ( ⁇ ) ⁇ (21)
- the first transit time measured in S202 is the transit time [Delta] T 3 as described with reference to FIG. 6, the second transit time measured at S203 is, propagation time difference as described with reference to FIG. 7
- Expressions (24) and (28) are added and expressed by the following expression (29) using the addition theorem of trigonometric functions.
- V cos ⁇ C 2 ⁇ ⁇ T 2 / 4L cos ⁇
- the fluid velocity is calculated from the equation (30) based on the propagation time difference ⁇ T 2.
- the component V cos ⁇ parallel to the axis of the pipe A at the speed V can be calculated.
- the arithmetic control unit 55 reads the sound speed C, the propagation path length L, and the angle ⁇ stored in the memory or the like, and calculates the difference calculated in S204, for example, the propagation time difference ⁇ T 2 and the equation ( 30), a component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V is calculated (S205).
- the flow rate Q [m 3 / s] of the fluid flowing inside the pipe A is a component V cos ⁇ parallel to the correction coefficient K and the cross-sectional area S [m 2 ] of the pipe A and the axis of the pipe A at the fluid velocity V. [M / s] and is represented by the following formula (31).
- Q KSVcos ⁇ (31)
- the arithmetic control unit 55 reads the correction coefficient K and the cross-sectional area S stored in the memory or the like, and calculates the component Vcos ⁇ parallel to the axis of the pipe A at the fluid velocity V calculated in S205 and the equation (31). Then, the flow rate Q of the fluid flowing in the pipe A is calculated (S206), and the fluid velocity measurement process S200 is terminated.
- the first fluid propagation path is a path that traverses (crosses) the inside of the pipe A in the radial direction three times, and the second fluid propagation path passes through the inside of the pipe A once in the radial direction.
- traversing (crossing) route an example of a traversing (crossing) route has been shown, the present invention is not limited to this.
- FIG. 9 is a side sectional view for explaining another example of calculation of the difference between the first propagation time difference and the second propagation time difference.
- the first fluid propagation path crosses the pipe A in the radial direction five times (crosses)
- the second fluid propagation path crosses the pipe A in the radial direction three times. It is a route (crossing).
- the path of the difference between the first fluid propagation path and the second fluid propagation path is the same as the case shown in FIG. 8 as shown by the solid line inside the pipe A in FIG. This is a path that traverses (crosses) twice in the radial direction.
- the arithmetic control unit 55 determines the fluid velocity V in S205 from the time difference calculated in S204, for example, the propagation time difference ⁇ T 2 and the equation (30). A component V cos ⁇ parallel to the axis of the pipe A can be calculated.
- FIG. 10 is a side sectional view for explaining still another example of calculation of the difference between the first propagation time difference and the second propagation time difference.
- the first fluid propagation path is a path that traverses (crosses) the inside of the pipe A in the radial direction seven times
- the second fluid propagation path traverses the inside of the pipe A in the radial direction five times. It is a route (crossing).
- the path of the difference between the first fluid propagation path and the second fluid propagation path is the same as in the case shown in FIGS. 8 and 9, as shown by the solid line inside the pipe A in FIG. This is a path that traverses (crosses) the inside of the pipe twice in the radial direction.
- the arithmetic control unit 55 determines the fluid flow in S205 from the difference calculated in S204, for example, the propagation time difference ⁇ T 2 and the equation (30).
- a component V cos ⁇ parallel to the axis of the pipe A at the speed V can be calculated.
- the difference between the first fluid propagation path and the second fluid propagation path is a path that traverses the pipe A twice in the radial direction (crosses).
- the difference path between the first fluid propagation path and the second fluid propagation path traverses the inside of the pipe A in the radial direction 2 (nm) times (m ⁇ n), that is, any even number of times (crosses). It is a route.
- the propagation time T 2nd for propagation of the ultrasonic wave transmitted from the first ultrasonic sensor 20A installed on the upstream side of the pipe A is:
- n times of the propagation time T 22d represented by the above-described equation (25) and the above-described equation (21). Since this is the sum of the propagation time T 21d and n ⁇ 1 times, it is expressed by the following equation (41).
- T 2nd nL / ⁇ C + Vcos ( ⁇ + ⁇ ) ⁇ + (n ⁇ 1) L / ⁇ C + Vcos ( ⁇ ) ⁇ (41)
- the propagation time T 2nu in which the ultrasonic wave transmitted from the second ultrasonic sensor 30A installed on the downstream side of the pipe A in the same path propagates is the propagation time T 22u represented by the above-described equation (26).
- n times of the propagation time T 21u expressed by the above-described equation (22), and is expressed by the following equation (42).
- T 2nu nL / ⁇ C ⁇ Vcos ( ⁇ + ⁇ ) ⁇ + (n ⁇ 1) L / ⁇ C ⁇ Vcos ( ⁇ ) ⁇ (42)
- the propagation time difference ⁇ T 2n (T 2nu ⁇ T 2nd ) between the propagation time T 2nu and the propagation time T 2nd is expressed by the following equation (43).
- ⁇ T 2n 2nLVcos ( ⁇ + ⁇ ) / ⁇ C 2 ⁇ V 2 cos ( ⁇ + ⁇ ) 2 ⁇ +2 (n ⁇ 1) LVcos ( ⁇ ) / ⁇ C 2 ⁇ V 2 cos ( ⁇ ) 2 ⁇ (43 )
- the route that traverses the pipe A 2m-1 times (crosses) in the radial direction is the same as the route that traverses the pipe A 2n-1 times (crosses) in the radial direction.
- the propagation time T 2md of the ultrasonic wave transmitted from the first ultrasonic sensor 20A installed on the upstream side of the pipe A and the second ultrasonic sensor 30A installed on the downstream side of the pipe A are transmitted.
- ⁇ T 2m 2LV ⁇ m ⁇ cos ( ⁇ + ⁇ ) + (m ⁇ 1) cos ( ⁇ ) ⁇ / C 2 (45)
- V cos ⁇ In the flow velocity V of the fluid having an angle ⁇ with respect to the axis of the pipe A, the component parallel to the axis of the pipe A is represented by V cos ⁇ .
- the component Vcos ⁇ is represented by the following formula (47).
- Vcos ⁇ C 2 ⁇ ⁇ T 2 (nm) / 4L (nm) cos ⁇ (47)
- equation (47) has no term including the angle ⁇ .
- equation (47) the values of sound velocity C, propagation path length L, angle ⁇ , and (nm) are known values before the fluid velocity is measured. Based on the time difference ⁇ T 2 (n ⁇ m) , a component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V can be calculated.
- the arithmetic control unit 55 reads the sound speed C, the propagation path length L, and the angle ⁇ stored in the memory or the like in S205 shown in FIG. 5, and calculates the difference calculated in S204, that is, the propagation time difference ⁇ T 2 (n ⁇ m) and the equation (47), a component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V is calculated (S205).
- the ultrasonic wave is downstream of the fluid propagation path traversing the inside of the pipe A in the radial direction 2 (nm) times, that is, even times. It is possible to obtain the propagation time difference between the time for propagation from the upstream side to the upstream side and the time for the ultrasonic wave to propagate from the upstream side to the downstream side.
- the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V is a known value before the measurement of the fluid velocity V, and the inside of the pipeline A is an even number in the radial direction.
- the arithmetic control unit 55 of the main body 50 performs the first propagation even when the fluid flow has an angle ⁇ with respect to the axis of the pipe A and the fluid velocity V includes a component perpendicular to the axis of the pipe A. Based on the time difference and the second propagation time difference, the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V can be accurately calculated.
- the component parallel to the axis of the pipe A at the fluid velocity V is calculated based on the first propagation time difference and the second propagation time difference, the influence of the component perpendicular to the axis of the pipeline A at the fluid velocity V is obtained. Therefore, it is not necessary to arrange a long straight pipe on the upstream side.
- FIG. 11 is an enlarged cross-sectional view for explaining the angle of the ultrasonic wave transmitted by the first ultrasonic sensor 20A shown in FIG.
- the ultrasonic waves emitted from the ultrasonic transceiver 22 of the first ultrasonic sensor 20A is incident on the outer circumferential surface of the pipe A (outer wall) at an incident angle theta A.
- the refraction angle ⁇ B is determined by Snell's law as described above. For example, when the incident angle ⁇ A is 45 degrees and the material of the pipe A is stainless steel (SUS), the refraction angle ⁇ B is about 65 °.
- the ultrasonic wave propagating through the pipe A is incident on the inner wall of the pipe A at an incident angle (90 ° ⁇ B ) based on the refraction angle ⁇ B.
- the refraction angle ⁇ c is also determined by Snell's law as described above.
- the refraction angle ⁇ C when the fluid flowing in the pipe A is a liquid, for example, water, the refraction angle ⁇ C is about 16 °. In this case, the aforementioned angle ⁇ is about 74 °.
- the refraction angle ⁇ C is about 5 °. In this case, the aforementioned angle ⁇ is about 85 °.
- the angle ⁇ of the ultrasonic wave propagating through the fluid is relatively large, and the ultrasonic wave transmitted from the first ultrasonic sensor 20A propagates through the fluid inside the pipe A at an angle ⁇ close to vertical.
- the fluid flowing inside the pipe A is a gas
- the sound speed C is slower than when the fluid is a liquid, and therefore the angle ⁇ tends to increase.
- the ultrasonic incident angle is not allowed to exceed the critical angle at the interface between the wedge 21 and the outer wall of the pipe A and the interface between the inner wall of the pipe A and the fluid inside the pipe A, the incident angle ⁇ A
- the range that can be selected is narrowed, and there is little room for selection of the angle ⁇ of the ultrasonic wave.
- FIG. 11 shows an example of ultrasonic waves transmitted by the first ultrasonic sensor 20A, but the same applies to ultrasonic waves transmitted by the second ultrasonic sensor 30A. Therefore, the description of the ultrasonic wave transmitted by the second ultrasonic sensor 30A is omitted with the description of the ultrasonic wave transmitted by the first ultrasonic sensor 20A.
- FIG. 12 is a side cross-sectional view for explaining how the second ultrasonic sensor 30A receives the ultrasonic wave transmitted from the first ultrasonic sensor 20A shown in FIG. 1, and FIG. 13 shows the first ultrasonic sensor shown in FIG. It is a sectional side view explaining signs that the 1st ultrasonic sensor 20A receives the ultrasonic wave transmitted from 2A ultrasonic sensor 30A.
- the ultrasonic wave transmitted from the first ultrasonic sensor 20A with the size (length and width) of the ultrasonic transmitter / receiver 22 has a fluid velocity V of 0 (zero) [m / s].
- V fluid velocity
- the second ultrasonic sensor 30A is arranged to receive all of the ultrasonic waves, and the dimensions (length and width) of the ultrasonic transmitter / receiver 22 of the second ultrasonic sensor 30A are determined.
- the ultrasonic wave transmitted from the second ultrasonic sensor 30 ⁇ / b> A with the dimensions (length and width) of the ultrasonic transmitter / receiver 22 has a fluid velocity V of 0 (zero) [m / s], the fluid inside the pipe A propagates along the path indicated by the solid line inside the pipe A in FIG.
- the first ultrasonic sensor 20A is arranged to receive all of the ultrasonic waves, and the dimensions (length and width) of the ultrasonic transmitter / receiver 22 of the first ultrasonic sensor 20A are determined.
- the ultrasonic wave propagating through the fluid inside the pipe A is influenced by the fluid velocity V and is downstream (in FIGS. 12 and 13). To the right). That is, the ultrasonic waves transmitted from the first ultrasonic sensor 20A and the second ultrasonic sensor 30A propagate the fluid inside the pipe A through a path indicated by a broken line inside the pipe A in FIGS. Therefore, the first ultrasonic sensor 20A and the second ultrasonic sensor 30A also take this case into consideration, and the maximum value of the fluid velocity V that can be measured by the ultrasonic flowmeter 100, for example, 30 [m / s].
- the dimensions of the wedge 21, particularly the pipe A so as to receive a predetermined proportion of the ultrasonic waves transmitted in the dimensions (length and width) of the ultrasonic transmitter / receiver 22, for example, 50% of the ultrasonic waves. Determine the axial length.
- the sonic flow meter 100 can install the first ultrasonic sensor 20 ⁇ / b> A and the second ultrasonic sensor 30 ⁇ / b> A on the outer periphery of the pipe A.
- the fluid flows at a velocity V along a direction parallel to the axis of the pipe A, and the ultrasonic waves radially run inside the pipe A.
- An example of a path that crosses once is shown.
- the ultrasonic waves transmitted from the first ultrasonic sensor 20A and the second ultrasonic sensor 30A pass through the inside of the pipe A in the radial direction 2n-1 times, and the pipe.
- the first ultrasonic sensor 20A and the second super sensor are based on the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V.
- the arrangement of the acoustic wave sensor 30A and the dimensions of the ultrasonic transceiver 22 and the wedge 21 are determined.
- the virtual ultrasonic flowmeter includes a first ultrasonic sensor 120A and a second ultrasonic sensor 130A having the same configuration as the first ultrasonic sensor 20A and the second ultrasonic sensor 30A of the ultrasonic flowmeter 100,
- the ultrasonic flowmeter 100 is the same as the ultrasonic flowmeter 100 except that the arrangement of the first ultrasonic sensor 120A and the second ultrasonic sensor 130A is different. As shown in FIGS.
- the first ultrasonic sensor 120 ⁇ / b> A and the second ultrasonic sensor 130 ⁇ / b> A are on one side of the pipe A (the upper side in FIGS. 14 and 15). Arranged on the same straight line.
- the ultrasonic wave travels (moves) along the x-axis direction. The distance is very short. Therefore, in the virtual ultrasonic flow meter, when the fluid velocity V is 0 (zero) [m / s], as in the case of FIGS.
- the ultrasonic sensor 130A is arranged so as to receive all of the ultrasonic waves transmitted in the dimensions (length and width) of the ultrasonic transmitter / receiver 22, the first ultrasonic sensor 120A and the second ultrasonic sensor 130A are close to each other. Need to be placed.
- the ultrasonic waves transmitted from the first ultrasonic sensor 120 ⁇ / b> A and the second ultrasonic sensor 130 ⁇ / b> A are reflected by the fluid propagation wave propagating through the fluid inside the pipe A and the pipe wall of the pipe A so as to pass through the pipe A. It can be divided into propagating pipe propagating waves.
- the fluid propagation wave is a signal (signal component) to be detected, while the pipe propagation wave is noise (noise component) with respect to the signal.
- the first ultrasonic sensor 120A and the second ultrasonic sensor 130A are arranged close to each other, it becomes easy to receive a pipe propagation wave that is a noise component. And it becomes difficult to distinguish.
- the ultrasonic transceiver 22 when the maximum value of the fluid velocity V that can be measured is, for example, 30 [m / s], the ultrasonic transceiver 22 When the dimension of the wedge 21 (the length in the axial direction of the pipe A) is determined so as to receive 50% of the ultrasonic waves transmitted in the dimensions (length and length), the first ultrasonic sensor The 120A and the second ultrasonic sensor 130A interfere with each other, thereby hindering (preventing) installation.
- the maximum value of the fluid velocity V that can be measured is limited to, for example, less than 20 [m / s], and the dimensions of the wedge 21 (the pipe A It is necessary to reduce the axial length).
- the ultrasonic flowmeter 100 includes a first ultrasonic sensor 20 ⁇ / b> A of the first ultrasonic transmission / reception unit 20 and a second ultrasonic sensor of the second ultrasonic transmission / reception unit 30.
- 30A is arranged across the fluid flowing inside the pipe A.
- FIG. As compared with the case where the first ultrasonic sensor 120A and the second ultrasonic sensor 130A are arranged on the same straight line of the pipe A as in the virtual ultrasonic flow shown in FIG. It becomes difficult to do.
- the arithmetic control unit 55 calculates the difference between the second propagation time difference and the first propagation time difference in S204, and in S205, from this difference and Expression (47), the axis of the pipe A at the fluid velocity V is calculated.
- the parallel component Vcos ⁇ is calculated.
- the first ultrasonic transmission / reception unit 20 and the second ultrasonic transmission / reception unit 30 are arranged with the fluid flowing inside the pipe A interposed therebetween, and the main body unit 50.
- the first propagation time difference which is the difference between the transmission time and the propagation time of the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit 20, and the inside of the pipe A in the radial direction 2m-1 times (m is a positive value other than n)
- a second propagation time difference based on the fluid velocity of the pipe Calculating a component parallel to the axis.
- the ultrasonic wave is transmitted from the downstream side in the fluid propagation path traversing the inside of the pipe A in the radial direction 2 (nm) times, that is, even times. It is possible to obtain the propagation time difference between the time for propagation to the upstream side and the time for the ultrasonic wave to propagate from the upstream side to the downstream side.
- the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity crosses the inside of the pipe A in the radial direction an even number of times before the measurement of the fluid velocity V.
- a propagation time difference ⁇ T 2 (n ⁇ m) a propagation time difference ⁇ T 2 (n ⁇ m) .
- the arithmetic control unit 55 of the main body 50 performs the first propagation even when the fluid flow has an angle ⁇ with respect to the axis of the pipe A and the fluid velocity V includes a component perpendicular to the axis of the pipe A. Based on the time difference and the second propagation time difference, the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V can be accurately calculated. Therefore, the ultrasonic flowmeter 100 can accurately measure the fluid flow rate Q based on the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V.
- the ultrasonic flow meter 100 can relax the restriction (restriction) of the installation position, and can be installed at any place, for example, immediately after a bent pipe.
- the first ultrasonic sensor 20A of the first ultrasonic transmission / reception unit 20 and the second ultrasonic sensor 30A of the second ultrasonic transmission / reception unit 30 are arranged with the fluid flowing inside the pipe A interposed therebetween.
- the ultrasonic flowmeter 100 can easily expand the measurable flow velocity range by increasing the dimensions (the length of the pipe A in the axial direction) of the first ultrasonic transmission / reception unit 20 and the second ultrasonic transmission / reception unit 30. Can do.
- FIG. As compared with the case where the first ultrasonic sensor 120A and the second ultrasonic sensor 130A are arranged on the same straight line as the virtual ultrasonic flow rate shown in FIG. It becomes difficult. Therefore, the ultrasonic flowmeter 100 can improve the SN ratio.
- the first ultrasonic transmission / reception unit 20 includes the first ultrasonic sensor 20A installed on the outer periphery of the pipe A
- the second ultrasonic transmission / reception unit 30 includes the pipe A.
- the second ultrasonic sensor 30 ⁇ / b> A installed on the outer periphery is provided.
- the first fluid propagation path is a path that traverses the inside of the pipe A three times in the radial direction
- the second fluid propagation path is the radial direction in the pipe A.
- This is a route that crosses once.
- the propagation time difference ⁇ t 3 and the propagation time difference ⁇ t 1 the propagation time difference ⁇ T 2 of the path traversing the inside of the pipe A twice in the radial direction can be easily obtained, and the pipe A at the fluid velocity V is obtained.
- the main body 50 that calculates the component V cos ⁇ parallel to the axis can be easily realized (configured).
- the first fluid propagation path is a path that traverses the inside of the pipe A five times in the radial direction
- the second fluid propagation path is the radial direction in the pipe A. This is a route that crosses three times.
- the propagation time difference ⁇ t 5 and the propagation time difference ⁇ t 3 the propagation time difference ⁇ T 2 of the path traversing the inside of the pipe A twice in the radial direction can be easily obtained, and the pipe A at the fluid velocity V is obtained.
- the main body 50 that calculates the component V cos ⁇ parallel to the axis can be easily realized (configured).
- the first fluid propagation path is a path that traverses the inside of the pipe A in the radial direction seven times
- the second fluid propagation path is the radial direction in the pipe A. This is a route that crosses 5 times.
- the propagation time difference ⁇ t 7 and the propagation time difference ⁇ t 5 the propagation time difference ⁇ T 2 of the path traversing the inside of the pipe A in the radial direction twice can be easily obtained, and the pipe A at the fluid velocity V is obtained.
- the main body 50 that calculates the component V cos ⁇ parallel to the axis can be easily realized (configured).
- the first fluid propagation path that traverses the inside of the pipe A 2n-1 times (n is a positive integer) in the radial direction The first propagation time difference, which is the difference between the time during which the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit 30 propagates and the time during which the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit 20 propagates, and the inside of the pipe A
- a step of calculating a component parallel to the axis of the pipe A at the fluid velocity based on the second propagation time difference, which is a difference from the time during which the ultrasonic wave transmitted from the unit 20 propagates, is included.
- the ultrasonic wave is transmitted from the downstream side in the fluid propagation path that traverses the inside of the pipe A in the radial direction 2 (nm) times, that is, an even number of times. It is possible to obtain the propagation time difference between the time for propagation to the upstream side and the time for the ultrasonic wave to propagate from the upstream side to the downstream side. As shown in the equation (47), the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity crosses the inside of the pipe A in the radial direction an even number of times before the measurement of the fluid velocity V. For example, a propagation time difference ⁇ T 2 (n ⁇ m) .
- the arithmetic control unit 55 of the main body 50 performs the first propagation even when the fluid flow has an angle ⁇ with respect to the axis of the pipe A and the fluid velocity V includes a component perpendicular to the axis of the pipe A. Based on the time difference and the second propagation time difference, the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V can be accurately calculated. Therefore, the ultrasonic flowmeter 100 can accurately measure the fluid flow rate Q based on the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V.
- the ultrasonic flow meter 100 can relax the restriction (restriction) of the installation position, and can be installed at any place, for example, immediately after a bent pipe.
- the first ultrasonic sensor 20A of the first ultrasonic transmission / reception unit 20 and the second ultrasonic sensor 30A of the second ultrasonic transmission / reception unit 30 are arranged with the fluid flowing inside the pipe A interposed therebetween.
- the ultrasonic flowmeter 100 can easily expand the measurable flow velocity range by increasing the dimensions (the length of the pipe A in the axial direction) of the first ultrasonic transmission / reception unit 20 and the second ultrasonic transmission / reception unit 30. Can do.
- FIG. As compared with the case where the first ultrasonic sensor 120A and the second ultrasonic sensor 130A are arranged on the same straight line as the virtual ultrasonic flow rate shown in FIG. It becomes difficult. Therefore, the ultrasonic flowmeter 100 can improve the SN ratio.
- the fluid velocity measurement process S200 traverses the inside of the pipe A 2n-1 times (n is a positive integer) in the radial direction.
- the first propagation which is the difference between the time for the ultrasonic wave transmitted from the second ultrasonic wave transmitting / receiving unit 30 to propagate through the first fluid propagation path and the time for the ultrasonic wave transmitted from the first ultrasonic wave transmitting / receiving unit 20 to propagate.
- the ultrasonic wave transmitted from the second ultrasonic transmission / reception unit 30 propagates through the second fluid propagation path that crosses the time difference and the inside of the pipe A in the radial direction 2m-1 times (m is a positive integer other than n).
- the second propagation time difference which is the difference between the time and the propagation time of the ultrasonic wave transmitted from the first ultrasonic transmission / reception unit 20 including.
- the ultrasonic wave is transmitted from the downstream side in the fluid propagation path that traverses the inside of the pipe A in the radial direction 2 (nm) times, that is, an even number of times. It is possible to obtain the propagation time difference between the time for propagation to the upstream side and the time for the ultrasonic wave to propagate from the upstream side to the downstream side.
- the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity crosses the inside of the pipe A in the radial direction an even number of times before the measurement of the fluid velocity V.
- a propagation time difference ⁇ T 2 (n ⁇ m) a propagation time difference ⁇ T 2 (n ⁇ m) . Therefore, the fluid velocity measurement process S200 is the same as the first propagation time difference and the first difference even when the fluid flow has an angle ⁇ with respect to the axis of the pipe A and the fluid velocity V includes a component perpendicular to the axis of the pipe A.
- the ultrasonic flowmeter 100 can accurately measure the fluid flow rate Q based on the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V.
- the ultrasonic flow meter 100 can relax the restriction (restriction) of the installation position, and can be installed at any place, for example, immediately after a bent pipe.
- the first ultrasonic sensor 20A of the first ultrasonic transmission / reception unit 20 and the second ultrasonic sensor 30A of the second ultrasonic transmission / reception unit 30 are arranged with the fluid flowing inside the pipe A interposed therebetween.
- the ultrasonic flowmeter 100 can easily expand the measurable flow velocity range by increasing the dimensions (the length of the pipe A in the axial direction) of the first ultrasonic transmission / reception unit 20 and the second ultrasonic transmission / reception unit 30. Can do.
- FIG. As compared with the case where the first ultrasonic sensor 120A and the second ultrasonic sensor 130A are arranged on the same straight line as the virtual ultrasonic flow rate shown in FIG. It becomes difficult. Therefore, the ultrasonic flowmeter 100 can improve the SN ratio.
- FIGS. 16 and 17 illustrate an ultrasonic flow meter, a fluid velocity measuring method, a fluid velocity measuring program, and a fluid velocity measuring method according to a second embodiment of the present invention.
- the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.
- components similar to those of the first embodiment described above are denoted by similar symbols, and detailed description thereof is omitted.
- the configuration, operation, and arrangement not shown are the same as those in the first embodiment described above.
- FIG. 16 is a configuration diagram showing a schematic configuration of the ultrasonic flowmeter 100A in the second embodiment.
- the ultrasonic flowmeter 100 ⁇ / b> A includes a first ultrasonic transmission / reception unit 20, a second ultrasonic transmission / reception unit 30, and a main body unit 50, similarly to the ultrasonic flowmeter 100.
- the first ultrasonic transmission / reception unit 20 includes a first ultrasonic sensor 20A and a first ultrasonic sensor 20B installed on the outer periphery of the pipe A.
- the second ultrasonic transmission / reception unit 30 includes two sensors, a second ultrasonic sensor 30A and a second ultrasonic sensor 30B, which are installed on the outer periphery of the pipe A.
- the first ultrasonic sensor 20 ⁇ / b> A of the first ultrasonic transmission / reception unit 20 is provided at a predetermined position of the pipe A
- the second ultrasonic sensor 30 ⁇ / b> A of the second ultrasonic transmission / reception unit 30 is the first ultrasonic transmission / reception unit 20.
- the pipe A is provided on the downstream side (right side in FIG. 16) with respect to the ultrasonic sensor 20A.
- the first ultrasonic sensor 20A of the first ultrasonic transmission / reception unit 20 is provided in the pipe A on the upstream side (left side in FIG. 16) with respect to the second ultrasonic sensor 30A of the second ultrasonic transmission / reception unit 30.
- the first ultrasonic sensor 20B of the first ultrasonic transmission / reception unit 20 is provided at a predetermined position of the pipe A
- the second ultrasonic sensor 30B of the second ultrasonic transmission / reception unit 30 is the first ultrasonic transmission / reception unit 20.
- the first ultrasonic sensor 20B is provided in the pipe A on the downstream side (right side in FIG. 16).
- the first ultrasonic sensor 20B of the first ultrasonic transmission / reception unit 20 is provided in the pipe A on the upstream side (left side in FIG. 16) with respect to the second ultrasonic sensor 30B of the second ultrasonic transmission / reception unit 30.
- first ultrasonic sensor 20A of the first ultrasonic transmission / reception unit 20 and the second ultrasonic sensor 30A of the second ultrasonic transmission / reception unit 30 are arranged to face each other with the fluid flowing in the pipe A interposed therebetween. Is done.
- first ultrasonic sensor 20B of the first ultrasonic transmission / reception unit 20 and the second ultrasonic sensor 30B of the second ultrasonic transmission / reception unit 30 are opposed to each other with the fluid flowing in the pipe A interposed therebetween. Be placed.
- the switching unit 51 of the main body unit 50 is connected to the first ultrasonic sensor 20A, the first ultrasonic sensor 20B, the second ultrasonic sensor 30A, and the second ultrasonic sensor 30B.
- the switching unit 51 switches the changeover switch based on the control signal input from the arithmetic control unit 55, for example, the first ultrasonic sensor 20A, the first ultrasonic sensor 20B, the second ultrasonic sensor 30A, and the second ultrasonic sensor.
- Any one of the sonic sensors 30 ⁇ / b> B is connected to the transmission circuit unit 52, and one capable of receiving the ultrasonic wave transmitted from the one is connected to the reception circuit unit 53.
- the second ultrasonic sensor 30A capable of receiving the ultrasonic wave transmitted from the first ultrasonic sensor 20A is used as the reception circuit unit. 53.
- FIG. 17 is a side sectional view for explaining an example of calculation of a difference between the first propagation time difference and the second propagation time difference in the second embodiment.
- the direction parallel to the axis of the pipe A is the x-axis (or the x-axis direction)
- the direction perpendicular to the x-axis and parallel to the diameter of the pipe A is y
- the x-axis, and the y-axis is defined as a z-axis (or z-axis direction).
- the velocity of the fluid is V [m / s]
- the velocity at which the ultrasonic wave propagates in the fluid (hereinafter referred to as the sound velocity) is C [m / s]
- the propagation of the ultrasonic wave that propagates the fluid It is assumed that the path length is L [m] and the angle between the inner wall of the pipe A and the ultrasonic propagation path is ⁇ .
- the example shown in FIG. 17 is a path in which the first fluid propagation path crosses the pipe A in the radial direction five times (crosses), and the second fluid propagation path crosses the inside of the pipe A in the radial direction three times. It is a route (crossing).
- the difference path between the first fluid propagation path and the second fluid propagation path is the inside of the pipe A as shown by the solid line inside the pipe A in FIG. 17. This is a path that traverses (crosses) twice in the radial direction.
- the first fluid propagation path is measured using the first ultrasonic sensor 20A and the second ultrasonic sensor 30A to measure the first propagation time difference, and the second fluid propagation path.
- the second propagation time difference is measured using the first ultrasonic sensor 20B and the second ultrasonic sensor 30B.
- the arithmetic control unit 55 uses the time difference calculated in S204 shown in FIG. 5, for example, the propagation time difference ⁇ T 2 (nm) and the equation (47 ). ),
- the component V cos ⁇ parallel to the axis of the pipe A at the fluid velocity V can be calculated in S205.
- the first fluid propagation path is a path that traverses (crosses) the inside of the pipe A five times in the radial direction
- the second fluid propagation path is three times in the radial direction inside the pipe A.
- the first fluid propagation path may be any path that traverses (crosses) the inside of the pipe A in the radial direction 2n-1 times (n is a positive integer)
- the second fluid propagation path is Any route that crosses (crosses) the inside of the pipe A in the radial direction 2m-1 times (m is a positive integer other than n) may be used.
- the first ultrasonic transmission / reception unit 20 includes the first ultrasonic sensor 20A and the first ultrasonic sensor 20B installed on the outer periphery of the pipe A.
- the second ultrasonic transmission / reception unit 30 includes a second ultrasonic sensor 30A and a second ultrasonic sensor 30B installed on the outer periphery of the pipe A.
- the first ultrasonic transmission / reception unit 20 includes two first ultrasonic sensors 20A and a first ultrasonic sensor 20B
- the second ultrasonic transmission / reception unit 30 includes two second ultrasonic sensors 30A and a second ultrasonic sensor.
- 30B for example, the first propagation time difference is measured using the first ultrasonic sensor 20A and the second ultrasonic sensor 30A, and the second propagation is performed using the first ultrasonic sensor 20B and the second ultrasonic sensor 30B. It becomes possible to measure the time difference.
- the same effects as the fluid velocity measuring method used by the ultrasonic flowmeter 100 of the first embodiment can be obtained.
- the same effects as the fluid velocity measurement program executed by the ultrasonic flowmeter 100 of the first embodiment can be obtained.
- the present invention can be applied to a technique for measuring the velocity of a fluid flowing through a pipe using ultrasonic waves.
- SYMBOLS 20 ... 1st ultrasonic transmission / reception part 20A, 20B ... 1st ultrasonic sensor 21 ... Wedge 21a ... Bottom 21b ... Slope 22 ... Piezoelectric element 30 ... 2nd ultrasonic transmission / reception part 30A, 30B ... 2nd ultrasonic sensor 50 ... Main body Reference numeral 51 ... Switching part 52 ... Transmission circuit part 53 ... Reception circuit part 54 ... Timer part 55 ... Calculation control part 56 ... Input / output part 100, 100A ... Ultrasonic flow meter A ... Piping
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Abstract
Description
図1ないし図15は、本発明に係る超音波流量計、流体速度測定方法および流体速度測定プログラム、および流体速度測定方法の第1実施形態を示すためのものである。図1は、第1実施形態における超音波流量計100の概略構成を示す構成図である。図1に示すように、超音波流量計100は、配管Aの内部を流れる流体、例えば、気体(ガス)や液体の流速を測定するためのものである。配管Aは、例えば、ステンレス鋼(SUS)などの金属製、または、プラスチックなどの樹脂製の管(管体)である。配管Aは、配管Aの軸(長手方向)が図1における左右方向、配管Aの径(短手方向)が図1における上下方向になるように配置されている。超音波流量計100の測定対象である流体は、図1において白抜き矢印で示す方向(図1における左から右の方向)に流れている。超音波流量計100は、第1超音波送受信部20と、第2超音波送受信部30と、本体部50と、を備える。
t1d=L/(C+Vcosθ) …(1)
t1u=L/(C-Vcosθ) …(2)
Δt1=2LVcosθ/(C2―V2cosθ2) …(3)
Δt1=2LVcosθ/C2 …(4)
V=C2・Δt1/2Lcosθ …(5)
Q=KSV …(6)
T1d=L/{C+Vcos(θ+ε)} …(11)
T1u=L/{C-Vcos(θ+ε)} …(12)
ΔT1=2LVcos(θ+ε)/{C2―V2cos(θ+ε)2} …(13)
ΔT1=2LVcos(θ+ε)/C2 …(14)
V=C2・ΔT1/2Lcos(θ+ε) …(15)
T21d=L/{C+Vcos(θ-ε)} …(21)
T21u=L/{C-Vcos(θ-ε)} …(22)
ΔT21=2LVcos(θ-ε)/{C2―V2cos(θ-ε)2} …(23)
ΔT21=2LVcos(θ-ε)/C2 …(24)
T22d=L/{C+Vcos(θ+ε)} …(25)
T22u=L/{C-Vcos(θ+ε)} …(26)
ΔT22=2LVcos(θ+ε)/{C2―V2cos(θ+ε)2} …(27)
Δt22=2LVcos(θ+ε)/C2 …(28)
ΔT2=2LV(cosθcosε+sinθsinε+cosθcosε-sinθsinε)/C2=4LVcosθcosε/C2 …(29)
Vcosε=C2・ΔT2/4Lcosθ …(30)
Q=KSVcosε …(31)
T2nd=nL/{C+Vcos(θ+ε)}+(n-1)L/{C+Vcos(θ-ε)} …(41)
一方、同じ経路について、配管Aの下流側に設置された第2超音波センサ30Aから送信された超音波が伝搬する伝搬時間T2nuは、前述した式(26)で表される伝搬時間T22uのn回分と、前述した式(22)で表される伝搬時間T21uのn-1回分との和であるから、以下の式(42)で表される。
T2nu=nL/{C-Vcos(θ+ε)}+(n-1)L/{C-Vcos(θ-ε)} …(42)
ΔT2n=2nLVcos(θ+ε)/{C2―V2cos(θ+ε)2}+2(n―1)LVcos(θ-ε)/{C2―V2cos(θ-ε)2} …(43)
ΔT2n=2LV{n・cos(θ+ε)+(n-1)cos(θ-ε)}/C2 …(44)
ΔT2m=2LV{m・cos(θ+ε)+(m-1)cos(θ-ε)}/C2 …(45)
ΔT2(n-m)=2LV(n-m){cos(θ+ε)+sin(θ-ε)}/C2=4LV(n-m)cosθcosε/C2 …(46)
Vcosε=C2・ΔT2(n-m)/4L(n-m)cosθ …(47)
図16および図17は、本発明に係る超音波流量計、流体速度測定方法および流体速度測定プログラム、および流体速度測定方法の第2実施形態を示すためのものである。なお、特に記載がない限り、前述した第1実施形態と同一構成部分は同一符号をもって表し、その説明を省略する。また、前述した第1実施形態と類似する構成部分は類似の符号をもって表し、その詳細な説明を省略する。さらに、図示しない構成、動作、および配置は、前述した第1実施形態と同様とする。
20A,20B…第1超音波センサ
21…くさび
21a…底面
21b…斜面
22…圧電素子
30…第2超音波送受信部
30A,30B…第2超音波センサ
50…本体部
51…切替部
52…送信回路部
53…受信回路部
54…計時部
55…演算制御部
56…入出力部
100,100A…超音波流量計
A…配管
Claims (8)
- 内部を流体が流れる配管に設けられ、超音波の送信および受信を行う第1の超音波送受信部と、
前記第1の超音波送受信部に対して下流側の前記配管に設けられ、超音波の送信および受信を行う第2の超音波送受信部と、
前記流体の速度を測定する本体部と、を備え、
前記第1の超音波送受信部および前記第2の超音波送受信部は、前記流体を挟んで配置され、
前記本体部は、前記配管の内部を径方向に2n-1回(nは正の整数)横断する第1の流体伝搬経路を、前記第2の超音波送受信部から送信された前記超音波が伝搬する時間と前記第1の超音波送受信部から送信された前記超音波が伝搬する時間との差である第1の伝搬時間差と、前記配管の内部を径方向に2m-1回(mはn以外の正の整数)横断する第2の流体伝搬経路を、前記第2の超音波送受信部から送信された前記超音波が伝搬する時間と前記第1の超音波送受信部から送信された前記超音波が伝搬する時間との差である第2の伝搬時間差と、に基づいて、前記流体の速度における前記配管の軸に平行な成分を算出する、
超音波流量計。 - 前記第1の超音波送受信部および前記第2の超音波送受信部のそれぞれは、前記配管の外周に設置される超音波センサを備える、
請求項1に記載の超音波流量計。 - 前記第1の超音波送受信部および前記第2の超音波送受信部のそれぞれは、前記配管の外周に設置される超音波センサを2つ備える、
請求項1に記載の超音波流量計。 - 前記第1の流体伝搬経路は、前記配管の内部を径方向に3回横断する経路であり、
前記第2の流体伝搬経路は、前記配管の内部を径方向に1回横断する経路である、
請求項1ないし3のいずれか一項に記載の超音波流量計。 - 前記第1の流体伝搬経路は、前記配管の内部を径方向に5回横断する経路であり、
前記第2の流体伝搬経路は、前記配管の内部を径方向に3回横断する経路である、
請求項1ないし3のいずれか一項に記載の超音波流量計。 - 前記第1の流体伝搬経路は、前記配管の内部を径方向に7回横断する経路であり、
前記第2の流体伝搬経路は、前記配管の内部を径方向に5回横断する経路である、
請求項1ないし3のいずれか一項に記載の超音波流量計。 - 内部を流体が流れる配管に設けられ、超音波の送信および受信を行う第1の超音波送受信部と、前記第1の超音波送受信部に対して下流側の前記配管に設けられ、超音波の送信および受信を行う第2の超音波送受信部と、前記流体の速度を測定する本体部と、を備え、前記第1の超音波送受信部および前記第2の超音波送受信部は、前記流体を挟んで配置される超音波流量計が使用する流体速度測定方法であって、
前記配管の内部を径方向に2n-1回(nは正の整数)横断する第1の流体伝搬経路を、前記第2の超音波送受信部から送信された前記超音波が伝搬する時間と前記第1の超音波送受信部から送信された前記超音波が伝搬する時間との差である第1の伝搬時間差と、前記配管の内部を径方向に2m-1回(mはn以外の正の整数)横断する第2の流体伝搬経路を、前記第2の超音波送受信部から送信された前記超音波が伝搬する時間と前記第1の超音波送受信部から送信された前記超音波が伝搬する時間との差である第2の伝搬時間差と、に基づいて、前記流体の速度における前記配管の軸に平行な成分を算出するステップを含む、
流体速度測定方法。 - 内部を流体が流れる配管に設けられ、超音波の送信および受信を行う第1の超音波送受信部と、前記第1の超音波送受信部に対して下流側の前記配管に設けられ、超音波の送信および受信を行う第2の超音波送受信部と、前記流体の速度を測定する本体部と、を備え、前記第1の超音波送受信部および前記第2の超音波送受信部は、前記流体を挟んで配置される超音波流量計が実行する流体速度測定プログラムであって、
前記配管の内部を径方向に2n-1回(nは正の整数)横断する第1の流体伝搬経路を、前記第2の超音波送受信部から送信された前記超音波が伝搬する時間と前記第1の超音波送受信部から送信された前記超音波が伝搬する時間との差である第1の伝搬時間差と、前記配管の内部を径方向に2m-1回(mはn以外の正の整数)横断する第2の流体伝搬経路を、前記第2の超音波送受信部から送信された前記超音波が伝搬する時間と前記第1の超音波送受信部から送信された前記超音波が伝搬する時間との差である第2の伝搬時間差と、に基づいて、前記流体の速度における前記配管の軸に平行な成分を算出するステップを含む、
流体速度測定プログラム。
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US9618371B2 (en) | 2017-04-11 |
CN105209865A (zh) | 2015-12-30 |
JP5875999B2 (ja) | 2016-03-02 |
JP2014182097A (ja) | 2014-09-29 |
US20160290845A1 (en) | 2016-10-06 |
CN105209865B (zh) | 2018-07-06 |
KR101680998B1 (ko) | 2016-11-29 |
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