JP5965292B2 - Ultrasonic flow meter - Google Patents

Description

  The present invention changes the flow of the fluid under measurement by changing both the transmission side and the reception side between a pair of ultrasonic transmitters / receivers provided along the flow direction of the fluid under measurement in the flow path through which the fluid under measurement flows. The present invention relates to an ultrasonic flowmeter that transmits and receives an ultrasonic beam so as to cross and measures the flow rate of a fluid to be measured based on the difference in the propagation state of both ultrasonic waves.

  For example, the flow rate of a fluid to be measured such as city gas is measured by an ultrasonic transmitter / receiver (transducer) that is displaced from the upstream and downstream sides of the tube wall of the measurement tube through which the fluid to be measured flows. An ultrasonic sensor is arranged, and an ultrasonic beam is transmitted and received by crossing the flow of the fluid to be measured between the pair of upstream and downstream ultrasonic transmitters by changing both the transmitting side and the receiving side. The propagation time of the ultrasonic beam in the forward direction along the flow of the fluid to be measured between the pair of ultrasonic transceivers and the propagation time of the ultrasonic beam in the opposite direction against the flow of the fluid to be measured Is measured by calculating the flow velocity of the fluid to be measured from the difference between the propagation times of both, and by determining the volume flow rate of the fluid from the calculated flow velocity and the cross-sectional area of the flow channel of the measurement tube (for example, patents) Reference 1).

  Therefore, in the ultrasonic flowmeter, until the ultrasonic beam transmitted from the transmission-side ultrasonic transmitter / receiver between the pair of ultrasonic transmitter / receivers is received by the reception-side ultrasonic transmitter / receiver via the fluid to be measured. The higher the measurement accuracy of the propagation time of the ultrasonic beam in each of the forward direction and the reverse direction with respect to the flow direction of the fluid to be measured, the higher the flow rate of the fluid to be measured can be measured.

FIG. 6 is an explanatory diagram of the received signal of the ultrasonic beam received by the ultrasonic transceiver on the receiving side of the ultrasonic flowmeter.
In the figure, the vertical axis represents the voltage V, which is the reception output of the reception-side ultrasonic transceiver, and the horizontal axis represents the transmission point of the ultrasonic beam by the transmission-side ultrasonic transmitter / receiver at the origin O (V = 0, It represents a time lapse t with t = 0).

  As shown in FIG. 6 (A), the ultrasonic beam received signal Sgr received by the ultrasonic transmitter / receiver on the reception side includes the ultrasonic wave of the ultrasonic transmitter / receiver on the transmission side driven by the input of the drive signal. A predetermined periodic vibration based on the natural frequency of the vibrator is generated.

  In the example shown in the figure, when the transmission time of the ultrasonic beam in the ultrasonic transmitter / receiver on the transmission side, that is, the driving start point of the transmission / reception ultrasonic transmitter / receiver by the input of the drive signal is time t = 0, The arrival time of the ultrasonic beam to the ultrasonic transceiver is time t = t0. The direct detection of the time t0 from the reception output of the reception-side ultrasonic transmitter / receiver means that the previous ultrasonic beam has not yet reached the reception output of the reception-side ultrasonic transmitter / receiver (t0). This corresponds to detection of the output change start time due to arrival of the ultrasonic beam with respect to ≦ t <t0). However, since the reception output of the reception-side ultrasonic transmitter / receiver in which the ultrasonic beam is not reached normally includes noise due to, for example, acoustic reverberation in the flow path, the reception-side ultrasonic transmitter / receiver It is actually difficult to directly detect the arrival time t = t0 from the received output of the ultrasonic beam to the receiving side of the ultrasonic beam because of the S / N ratio.

  Therefore, the reception signal Sgr of the ultrasonic beam in the reception-side ultrasonic transmitter / receiver reflects the vibration of the ultrasonic transducer associated with the transmission of the ultrasonic beam by the transmission-side ultrasonic transmitter / receiver. As shown in the graph, the peak voltage of the signal wave for each period such as 1 wave, 2 waves, 3 waves,... Gradually increases and reaches the maximum value Vp (at the time indicated by x in the figure). After that, since it is received and output in a gradually decreasing waveform, conventionally, the nth wave (2 in the figure) in which the peak voltage becomes a voltage value that can be identified from the relationship of the S / N ratio after the second wave of the received signal. A zero cross point (time point tz indicated by a mark ■ in the figure) at the end time of the wave wave is detected, and the arrival of the ultrasonic beam on the receiving side is delayed by a predetermined cycle delay ΔT (in the figure, relative to the original arrival time point t0). 3/2 period delay). At that time, the detection of the n-th wave is set in advance so that the output of the ultrasonic transceiver on the receiving side is between the peak voltage value of the n-th wave and the peak voltage value of the n-1 wave, for example. This is performed by detecting the time point (the time point tn indicated by □ in the figure) when the reception output of the ultrasonic transmitter / receiver on the reception side first reaches the ultrasonic wave beam transmission time point t = 0 with respect to the voltage threshold Vth. ing. Therefore, the arrival time t = t0 of the ultrasonic beam to the receiving side (the time indicated by the mark ● in the figure) is t0 = if there is no mistake that the time tz is the zero cross point at the end of the nth wave. It can be obtained by calculating tz−ΔT.

  At that time, in the ultrasonic flowmeter, the voltage value Vpn at the peak time (at the time indicated by a circle in the figure) of the predetermined n-th wave (second wave in the figure) of the received signal Sgr of the received ultrasonic beam is predetermined. For example, the deviation of the peak voltage value Vpn of the nth wave (the second wave in the figure) of the received signal Sgr of the ultrasonic beam from the gain adjustment output value Vaj so that the gain adjustment output value Vaj Based on this, when the receiving side ultrasonic transceiver is operated again as the receiving side next time, the amplification gain (amplification factor) of the reception output is calculated, and when the receiving side is operated again as the receiving side next time, Gain adjustment is performed to amplify the reception output of the reception-side ultrasonic transceiver with the calculated amplification factor.

Japanese Patent Laid-Open No. 11-201791

  However, if there is a temporal or physical change in the fluid under measurement, such as the flow velocity of the fluid under measurement or the pressure of the fluid under measurement related to the density of the fluid under measurement during flow rate measurement, The above-mentioned receiver side so that the peak voltage value Vpn of the predetermined n-th wave (second wave in the figure) of the reception signal Sgr of the ultrasonic beam in the ultrasonic transmitter / receiver on the side becomes the gain adjustment output value Vaj. Even if the gain adjustment of the reception output related to the ultrasonic transmitter / receiver is performed, the reception signal Sgr of the ultrasonic beam changes greatly, and the reception of the ultrasonic beam amplified with the amplification factor obtained by the gain adjustment described above is received. The peak voltage value Vpn of the predetermined n-th wave (second wave in the figure) of the signal Sgr is greatly deviated from the gain adjustment output value Vaj as shown in FIGS. 6 (B) and 6 (C). Can happen. In such a case, the following problem occurs.

  For example, as shown in FIG. 6B, the peak voltage value Vpn of the predetermined n-th wave (second wave in the figure) of the received signal Sgr of the received ultrasonic beam is essentially the gain adjustment output value Vaj. Thus, even when the reception output of the ultrasonic transmitter / receiver on the receiving side is amplified with the amplification factor calculated by the gain adjustment, the n of the received signal Sgr is changed due to fluctuations in the flow velocity or pressure of the fluid to be measured. The peak voltage Vpn of the wave (second wave in the figure) does not reach the reception gain adjustment voltage value Vaj, and further, the peak voltage value of the nth wave (second wave in the figure) and the n-1 wave (1 in the figure). The peak voltage Vpn + of the next n + 1 wave (the third wave indicated by a circle in the figure) becomes lower than a preset voltage threshold Vth so as to be between the peak voltage values of the wave). 1 may reach the voltage threshold Vth. In this case, as a result of detecting this n + 1-th wave (the third wave in the figure) as the n-th wave (the second wave in the figure) of the reception signal Sgr, the ultrasonic flowmeter has an actual propagation time tz. Therefore, the propagation time value tz ′ = tz + Δt added by Δt is calculated as the propagation time tz. That is, the time when the ultrasonic beam reaches the receiving side is erroneously detected at t = t0 ′ with respect to the original t = t0.

  Further, as shown in FIG. 6C, the peak voltage value Vpn of the predetermined nth wave (second wave in the figure) of the received signal Sgr of the received ultrasonic beam is essentially the gain adjustment output value Vaj. Thus, even when the reception output of the ultrasonic transmitter / receiver on the receiving side is amplified with the amplification factor calculated by the gain adjustment, the n of the received signal Sgr is changed due to fluctuations in the flow velocity or pressure of the fluid to be measured. The peak voltage Vpn-1 of the −1st wave (the first wave indicated by a circle in the figure) is the peak voltage value of the nth wave (the 2nd wave in the figure) and the n−1th wave (the 1st wave in the figure). ) Becomes higher than a preset voltage threshold value Vth so as to be between the peak voltage values of (1) and reaches the voltage threshold value Vth at the peak voltage Vpn-1 of the (n-1) th wave before that. Sometimes it ends up. In this case, as a result of detecting this n-1 wave (1st wave in the figure) as the nth wave (2nd wave in the figure) of the received signal Sgr, the ultrasonic flowmeter actually transmits the wave. A value tz ′ = tz−Δt obtained by subtracting Δt from the time tz is calculated as the propagation time tz. That is, the time when the ultrasonic beam reaches the receiving side is erroneously detected at t = t0 ′ with respect to the original t = t0.

  As described above, in the conventional ultrasonic flowmeter, when temporal or physical fluctuation of the fluid to be measured occurs, the ultrasonic beam arrival time t = t0 is accurately determined in the ultrasonic transmitter / receiver on the receiver side. The calculated propagation time tz is a signal wave that deviates from the n-th wave (second wave in the figure) that should be detected in the signal wave for each period in the received signal Sgr. There is an error of Δt corresponding to the number, and there has been a problem that it is impossible to accurately measure the propagation time of the ultrasonic beam and thus the flow rate of the fluid to be measured.

  Further, when such arrival of the ultrasonic beam at the receiving side, that is, erroneous measurement of the propagation time tz has occurred, the above-described gain adjustment causes the ultrasonic beam that caused the erroneous measurement of the propagation time tz to occur. Of the received signal Sgr other than the n-th wave of the received signal Sgr with respect to the gain adjustment output value Vaj, the received output when the receiving side ultrasonic transmitter / receiver again operates as the receiving side next time The amplification gain (amplification factor) is calculated. Therefore, when the receiver is operated again as the receiver next time, gain adjustment for amplifying the reception output of the ultrasonic transmitter / receiver on the receiver side is performed with the calculated amplification factor. There was a problem that the wrong measurement was left.

  In view of the above-described problems, the present invention prevents erroneous measurement of the propagation time even when there is a temporal or physical variation in the fluid under measurement such as the pressure or flow velocity of the fluid under measurement. An object of the present invention is to provide an ultrasonic flowmeter capable of measuring an accurate flow rate of a measurement fluid.

  In order to achieve the above-described problem, an ultrasonic flowmeter according to the present invention is an ultrasonic flowmeter that is used to detect arrival of an ultrasonic beam at a reception side with a predetermined period delay in an ultrasonic transmitter / receiver on the reception side. Gain performed during normal flow measurement due to large fluctuations in the temporal or physical state of the fluid under measurement, such as the flow velocity or pressure of the fluid under measurement, in relation to the predetermined signal wave in the received signal of the sound beam The amplification factor for matching the peak voltage of the predetermined signal wave in the received signal of the ultrasonic beam calculated by the adjustment to the voltage value for gain adjustment is the predetermined gain in the received signal of the ultrasonic beam actually received. If there is a possibility that the peak voltage of the signal wave is different from the gain used to match the gain adjustment voltage value, this is detected and the received output gain of the ultrasonic transmitter / receiver is amplified. Calculates, separate from the normal gain adjustment performed in the flow rate measurement procedure, characterized in that to perform the procedure for the temporal or the physical state of the fluid to be measured greatly changes.

  An ultrasonic flowmeter according to the present invention includes a pair of ultrasonic transmitters / receivers provided in a measurement channel through which a fluid to be measured flows and the positions of the fluids to be measured shifted from each other along the flow direction of the fluid to be measured. So that the peak voltage of the predetermined wave in the reception signal of the ultrasonic beam transmitted from the ultrasonic transmitter / receiver on the transmission side and received by the ultrasonic transmitter / receiver on the reception side becomes a predetermined voltage. An amplification factor calculating means for calculating the amplification factor of the received signal, an amplification means for amplifying the reception signal by the ultrasonic transmitter / receiver on the reception side with the amplification factor calculated by the amplification factor calculating means, and a pair of ultrasonic transmitter / receiver In both the transmission side and the reception side, the ultrasonic beam is transmitted and received in the forward direction and the reverse direction with respect to the direction of the flow of the fluid to be measured, and between the pair of ultrasonic transceivers. Between the sender and receiver In response to the change in direction, a predetermined wave in the received signal of the ultrasonic beam received by the ultrasonic transmitter / receiver on the receiving side and amplified by the amplifying means is detected, and the detected wave is detected in order with respect to the flow direction of the fluid to be measured Measures the propagation time in each direction and reverse direction, and calculates the flow rate of the fluid to be measured from both propagation times, detects the temporal or physical fluctuation of the fluid to be measured, and detects the fluctuation. In such a case, the calculation of the amplification factor by the amplification factor calculation means is replaced with a procedure for directly adjusting the peak voltage of the predetermined wave when the fluctuation is not detected, and reception of an ultrasonic beam including the predetermined wave is received. And a gain calculation control means for performing the procedure for indirectly adjusting the maximum peak voltage of the signal.

According to the present invention, even when temporal or physical fluctuations of the fluid under measurement occur, such as the flow velocity or pressure of the fluid under measurement, the ultrasonic wave transmitter / receiver on the receiving side moves to the ultrasonic beam receiving side. It is possible to accurately detect the predetermined signal wave in the received signal of the ultrasonic beam used to detect the arrival of the signal with a predetermined period delay, and the error in the propagation time due to the inaccurate amplification factor. Measurement and, in turn, erroneous measurement of the flow rate of the fluid to be measured can be prevented.
Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

1 is an overall configuration diagram of an ultrasonic flowmeter according to an embodiment of the present invention. It is a flowchart of the flow measurement process which a flow measurement calculation control part performs as a flow measurement process part. It is a flowchart of the single wave jump detection process which a flow measurement calculation control part performs as a single wave jump detection process part. It is a flowchart of the single wave jump detection process which a flow measurement calculation control part performs as a single wave jump detection process part. It is a flowchart of the setting gain adjustment process which a flow measurement calculation control part performs as a setting gain adjustment process part. It is explanatory drawing of the received signal of the ultrasonic beam received with the ultrasonic transmitter / receiver of the receiving side of an ultrasonic flowmeter.

Hereinafter, the configuration and operation of an ultrasonic flowmeter according to an embodiment of the present invention will be described based on the drawings.
In the description, as shown in FIGS. 6B and 6C, in the ultrasonic flowmeter, a predetermined nth wave (2 in the figure) of the reception signal Sgr of the originally received ultrasonic beam is used. Even if the reception output of the ultrasonic transmitter / receiver on the receiving side is amplified with the amplification factor calculated by gain adjustment so that the peak voltage value Vpn of the wave) becomes the gain adjustment output value Vaj, As a predetermined n-th wave (second wave in the figure) of the received signal Sgr of the received ultrasonic beam due to fluctuations in the flow velocity or pressure of the fluid to be measured, n + 1 waves of the received signal Sgr of the actually received ultrasonic beam The phenomenon of erroneously detecting the eye (the third wave in the figure) or the n-1 wave (the first wave in the figure) is abbreviated as “one wave jump”, and this “one wave jump” occurs. This detection may be abbreviated as “one-wave jump detection”.

FIG. 1 is an overall configuration diagram of an ultrasonic flowmeter according to an embodiment of the present invention.
In FIG. 1, the ultrasonic flowmeter 1 is disposed on the upstream side along the flow direction of the fluid to be measured in the measurement channel 11 on the tube wall of the measurement channel 12 in which the measurement channel 11 through which the fluid to be measured flows is formed. It has a flow meter body 10 in which ultrasonic transmitters / receivers (transducers) 13 and 14 as ultrasonic sensors are arranged while being shifted from each other on the downstream side. In the illustrated example, the flow meter body 10 is provided with a pressure sensor 16 for detecting the pressure of the fluid to be measured located in the measurement flow path 11.

  An ultrasonic beam propagation path 15 using the fluid to be measured as a propagation medium is formed between the pair of upstream and downstream ultrasonic transceivers 13 and 14. The propagation path 15 is inclined by an angle θ with respect to the direction in which the fluid to be measured flows, in this case, the tube axis direction of the measurement pipe 12 in which the measurement flow path 11 is formed.

  Here, each of the ultrasonic transmitters / receivers 13 and 14 ultrasonically vibrates the transmitting / receiving surface facing the fluid to be measured by inputting the drive signal Sgd to transmit an ultrasonic beam into the fluid to be measured, while measuring the current to be measured. The ultrasonic vibration of the transmission / reception surface that vibrates upon reception of the ultrasonic beam propagating therethrough is taken out as an electrical output, and an ultrasonic beam reception signal Sgr as shown in FIG. 6 is output.

  In the ultrasonic flow meter 1 shown in FIG. 1, the propagation path 15 of the ultrasonic beam is transmitted and received by a pair of ultrasonic transmitters and receivers 13 and 14 disposed facing each other with the measurement flow path 11 in between. Measurement is performed on the side opposite to the side facing the transmission / reception surface of one of the ultrasonic transmitters / receivers 13 and 14. The measurement pipe 12 is configured to have an ultrasonic wave propagation path composed of an indirect propagation path of a V-shaped reflection system that is reflected on the pipe surface of the pipe line 12, or an ultrasonic beam transmitted / received from the transmission / reception surface of one ultrasonic wave transmitter / receiver 13. A configuration having an ultrasonic propagation path composed of an indirect propagation path of a multiple-reflection system that is reflected multiple times on the pipe surface and transmitted / received on the transmission / reception surface of the other ultrasonic transceiver 14 may be used.

  Further, the ultrasonic flowmeter 1 is configured so as to cross the flow of the fluid to be measured by changing the transmission side and the reception side between the pair of ultrasonic transceivers 13 and 14 at a predetermined measurement cycle interval. The ultrasonic beams are transmitted and received, and the propagation times Tau and Tad of the ultrasonic beams in the forward direction AU and the reverse direction AD with respect to the flow direction of the fluid to be measured in the measurement flow path 11 are measured. 11 is provided with a flow rate measurement computing device 20 that computes the flow rate Q of the fluid to be measured flowing through 11. Then, the flow measurement calculation device 20 outputs the measured flow Q to a display (not shown) or the like.

  In the illustrated example, the flow measurement calculation device 20 performs the flow measurement calculation described above, and in the illustrated example, the flow measurement calculation control unit 21, the drive signal output unit 22, the reception signal amplification unit 23, the transmission / reception side switching unit 24, and the gain switching unit. 25, a forward gain Gau setting unit 26, and a reverse gain Gad setting unit 27.

  The flow measurement calculation control unit 21 is configured by a calculation control device including a CPU, a memory, and the like, and controls the other parts of the flow measurement calculation calculation device 20, and includes a flow measurement processing unit 31, a single wave jump detection processing unit 32, It functions as the set gain adjustment processing unit 33.

  The flow measurement calculation control unit 21 changes the forward and reverse directions of the flow of the fluid to be measured by changing the transmission side and the reception side between the ultrasonic transmitters / receivers 13 and 14 as the flow measurement processing unit 31. The ultrasonic beam 13 is transmitted / received in each direction, and the ultrasonic wave transmitter / receiver 13 (or 14) which becomes the reception side in accordance with the change of both the transmission side and the reception side between the ultrasonic wave transmitters / receivers 13 and 14. ), And the propagation times Tau, Tad in the forward direction and the reverse direction with respect to the direction of the flow of the fluid to be measured, based on the received signal Sgr of the ultrasonic beam that is amplified and supplied by the received signal amplifier 23. And the flow rate Q of the fluid to be measured is calculated from the both propagation times Tau and Tad.

  The flow measurement calculation control unit 21 uses the predetermined wave n of the received signal Sgr of the received ultrasonic beam as shown in FIG. 6B and FIG. In the figure, as the second wave), the n + 1 wave (the third wave in the figure) or the n-1 wave (the first wave in the figure) of the reception signal Sgr of the actually received ultrasonic beam is erroneously detected. Detects the occurrence of the “one wave jump” phenomenon.

  Based on the detection result of the single jump detection processing unit 32, the flow measurement calculation control unit 21 performs normal gain adjustment setting processing during flow measurement and single jump generation during flow measurement as the set gain adjustment processing unit 33. The gain adjustment setting process at the time is selectively performed.

  Here, the normal gain adjustment processing during flow rate measurement is a predetermined n-th wave (2 in the figure) of the received signal Sgr of the received ultrasonic beam as shown in FIG. 6 during measurement of the fluid to be measured. The wave-th peak (the time indicated by a circle in the figure) is the n-th wave (in the figure) of the reception signal Sgr of the ultrasonic beam so that the voltage value Vpn at the predetermined gain adjustment output value Vaj Based on the deviation of the peak voltage value Vpn of the second wave) from the gain adjustment output value Vaj, the reception output when the reception side ultrasonic transmitter / receiver 13 (or 14) again operates as the reception side next time. A gain adjustment setting process for calculating an amplification gain (amplification factor) Ga (Gau, Gad).

  The flow measurement calculation control unit 21 is set when a single jump is detected by the single jump detection processing unit 32 during flow measurement or when an automatic or manual reset operation of the ultrasonic flow meter 1 is input. As the gain adjustment processing unit 33, instead of the above-described normal gain adjustment processing during flow rate measurement, the amplification gain (amplification factor) Ga (Gau, Gad) is calculated.

  In relation to the single-jump detection processing unit 32, a pressure measurement value of the fluid to be measured by the pressure sensor 16 is also input to the flow measurement calculation control unit 21. In the example shown in the figure, the flow meter body 10 is provided with the pressure sensor 16 in order to measure the pressure of the fluid to be measured. You may make it utilize the pressure sensor with which the transfer pipe of the to-be-measured fluid connected by piping to the meter main body 10 was equipped.

  The drive signal output unit 22 amplifies the drive signal supplied from the flow measurement calculation control unit 21 for causing the transmission side ultrasonic transceiver to oscillate the ultrasonic beam, and outputs the amplified signal to the transmission / reception side switching unit 24.

  The reception signal amplifying unit 23 is connected to the reception output from the reception-side ultrasonic transmitter / receiver selectively supplied via the transmission / reception side switching unit 24, and is connected to the forward gain Gau via the gain switching unit 25. Amplified by the amplification gain Gau or Gad set in one of the setting unit 26 and the reverse direction gain Gad setting unit 27, and output to the flow measurement calculation control unit 21.

  Based on the connection instruction supplied from the flow measurement calculation control unit 21, the transmission / reception side switching unit 24 converts the ultrasonic transmitter / receiver connected to the drive signal output unit 22 and the reception signal amplification unit 23 to the ultrasonic transmitter / receiver 13, Switch between 14

  As in the case of the transmission / reception side switching unit 24, the gain switching unit 25 changes the gain setting unit connected to the reception signal amplification unit 23 based on the connection instruction supplied from the flow rate measurement calculation control unit 21 to the forward gain Gau. Switching between the setting unit 26 and the reverse gain Gad setting unit 27 is performed.

  The connection instruction to each of the transmission / reception side switching unit 24 and the gain switching unit 25 is, for example, measurement of the forward propagation time Tau or the reverse propagation time Tad with respect to the flow direction of the fluid to be measured by the flow rate measurement processing unit 31. Depending on the type, or depending on the adjustment type of the forward gain Gau or the reverse gain Gad by the set gain adjustment processing unit 33, it is supplied from the flow measurement calculation control unit 21.

  The forward gain Gau setting unit 26 stores the forward gain Gau set or adjusted by the setting gain adjustment processing unit 33 supplied from the flow measurement calculation control unit 21. The reverse gain Gad setting unit 27 stores the reverse gain Gad set or adjusted by the setting gain adjustment processing unit 33 supplied from the flow measurement calculation control unit 21.

  Next, functions executed by the flow measurement calculation control unit 21 of the flow meter 1 as the flow measurement processing unit 31, the single wave jump detection processing unit 32, and the set gain adjustment processing unit 33 will be described with reference to FIGS. To do. Hereinafter, in description, step S10 is described as S10, and description of the step is omitted.

FIG. 2 is a flowchart of a flow measurement process executed by the flow measurement calculation control unit as the flow measurement processing unit.
The flow measurement calculation control unit 21 executes a flow measurement process at a predetermined measurement cycle interval.

  In the ultrasonic flow meter 1, when the flow measurement processing by the flow measurement calculation control unit 21 is started, first, in S10, the flow measurement calculation control unit 21 sets, for example, the ultrasonic beam transmission side of the fluid to be measured. The transmission / reception side switching unit 24 and the gain switching unit 25 are switched so that the ultrasonic transmission / reception unit 13 on the upstream side in the flow direction and the ultrasonic transmission / reception unit 14 on the downstream side in the flow direction of the fluid to be measured are switched. An ultrasonic beam is transmitted and received between the sound wave transmitters and receivers 13 and 14 in the forward direction with respect to the flow direction of the fluid to be measured. Then, the flow measurement calculation control unit 21 uses the ultrasonic wave reception signal Sgr amplified by the reception signal amplification unit 23 with the forward gain Gau stored in the forward gain Gau setting unit 26, as shown in FIG. ), The zero cross point (time point tz indicated by ■ in the figure) at the end point of the predetermined n-th wave (second wave in the figure) is detected, and the flow direction of the fluid to be measured is detected. All forward propagation times Tau are measured.

  Next, in S20, the flow measurement calculation control unit 21 sets the ultrasonic beam transmitting side as the ultrasonic transmitter / receiver 14 on the downstream side in the flow direction of the fluid to be measured, and the receiving side as the upstream side in the flow direction of the fluid to be measured. The transmission / reception side switching unit 24 and the gain switching unit 25 are switched so that the transmission / reception side is changed on both sides so that the ultrasonic transmission / reception unit 13 of the ultrasonic transmission / reception unit 13 is changed. Transmit and receive ultrasonic beams in the direction. Then, the flow measurement calculation control unit 21 performs predetermined n waves based on the reception signal Sgr of the ultrasonic beam amplified by the reception signal amplification unit 23 with the reverse direction gain Gad stored in the reverse direction gain Gad setting unit 27. The zero cross point tz at the end of the eye (second wave in the figure) is detected, and the propagation time Tad in the direction opposite to the flow direction of the fluid to be measured is measured.

  Next, in S30, the flow measurement calculation control unit 21 obtains the flow velocity q of the fluid to be measured from the difference between the forward propagation time Tau and the reverse propagation time Tad measured in S10 and S20, and further obtains the obtained flow velocity. The volume flow rate Q of the fluid is obtained from q and the flow path cross-sectional area perpendicular to the pipe axis direction of the measurement pipe 12.

  Next, in S40, the flow measurement calculation control unit 21 performs a single-wave jump detection process as the single-wave jump detection processing unit 32, and sets the transmission side of the ultrasonic beam on the downstream side in the flow direction of the fluid to be measured. Measurement of propagation times Tau and Tad in the forward and reverse directions indicated by S10 and S20 when the ultrasonic transmitter / receiver 14 is used and the receiving side is the ultrasonic transmitter / receiver 13 upstream in the flow direction of the fluid to be measured. , The n + 1-th wave (the third wave in the figure) or the n-th wave of the received signal Sgr of the actually received ultrasonic beam as the predetermined n-th wave (the second wave in the figure) of the received signal Sgr of the received ultrasonic beam or n A so-called “one-wave jump” is detected that erroneously detects the first wave (the first wave in the figure).

  Next, in S50, the flow measurement calculation control unit 21 determines in S30 that “one-wave jump” is not detected in the measurement of the propagation times Tau and Tad in the forward direction and the backward direction (S10 and S20) in S40. The flow rate Q calculated in step 1 is output to a display (not shown).

  Next, in S60, the flow measurement calculation control unit 21 performs a normal gain adjustment setting process during flow measurement as the set gain adjustment processing unit 33. That is, the flow measurement calculation control unit 21 is associated with the execution of the flow measurement process in the current measurement cycle, and the super-measurements acquired at the time of measuring the propagation times Tau and Tad in the forward direction and the reverse direction shown in S10 and S20, respectively. Each of the sound wave transceivers 14 and 13 is amplified by the reception signal amplification unit 23 with the forward gain Gau and the reverse gain Gad stored in the forward gain Gau setting unit 26 and the reverse gain Gad setting unit 27, respectively. Based on the peak voltage value Vpn of the predetermined n-th wave (second wave in the figure) of the reception signal Sgr of the ultrasonic beam, the peak voltage value Vpn is set so that the peak voltage value Vpn becomes the predetermined gain adjustment output value Vaj. Based on the deviation of the voltage value Vpn from the gain adjustment output value Vaj, the forward direction setting gain Gau and the reverse direction setting when the ultrasonic transceivers 14 and 13 again operate as the receiving side in the next measurement cycle. To calculate the in-Gad.

  Next, in S70, the flow measurement calculation control unit 21 updates and stores the forward direction setting gain Gau and the reverse direction setting gain Gad calculated in S60 in the forward direction gain Gau setting unit 26 and the reverse direction gain Gad setting unit 27. .

  Therefore, in the flow measurement process executed by the flow measurement calculation control unit 21 at predetermined measurement intervals, it is confirmed that no single jump has occurred in the single jump detection process shown in S40. The forward direction setting gain Gau and the reverse direction setting gain Gad acquired by the reception signal amplifying unit 23 by the normal gain adjustment setting process during flow rate measurement described in S60 are feedback-adjusted for each measurement cycle, and predetermined gain adjustment is performed. Is maintained at an optimum gain with reference to the output value Vaj.

  Next, the single wave jump detection process executed by the flow measurement calculation control unit 21 as the single wave jump detection processing unit 32 in S40 of the flow rate measurement process will be described with reference to FIGS.

3 and 4 are flowcharts of the single-jump detection process executed by the flow measurement calculation control unit as the single-jump detection processing unit.
When the execution of the one-wave jump detection process by the flow measurement calculation control unit 21 is started, first, in S401, the flow measurement calculation control unit 21 executes the flow measurement process at the current measurement cycle (in this case, the nth time). Therefore, the forward propagation time Tau measured in S10 and the backward propagation time Tad measured in S20 are added, and whether or not the absolute value | Tau + Tad | is substantially equal to the predetermined time. Determine.

  Here, the addition of the forward propagation time Tau and the backward propagation time Tad measured by the flow rate measurement process in the same measurement cycle cancels the shortened and delayed propagation time due to the flow of the fluid to be measured. The predetermined time corresponds to a value twice the propagation time T when there is no flow of the fluid to be measured.

  Therefore, the flow measurement calculation control unit 21 assumes that the propagation distance T when the flow of the ultrasonic beam is L and the velocity of sound is C, and the propagation time T when there is no flow of the fluid to be measured is the time L / C. When Tau + Tad | is not substantially equal to the predetermined time and deviates from the allowable error range, it is equal to at least one of the measurement of the forward propagation time Tau and the measurement of the reverse propagation time Tad. It is estimated that a wave jump has occurred, and the occurrence of a single wave jump is detected.

  In S401, the flow measurement calculation control unit 21 detects the occurrence of a single jump when the absolute value | Tau + Tad | is not substantially equal to the predetermined time, but instead of this, In addition, one jump may be detected as shown in S402.

  In S402, a one-wave jump is detected based on an abnormality of the time difference | α + β | between the transmission time Tau of the ultrasonic beam in the forward direction AU and the transmission time Tad of the ultrasonic beam in the reverse direction AD of the fluid to be measured.

That is, when the transmission time of the ultrasonic beam between the ultrasonic transceivers 13 and 14 when the fluid to be measured is not flowing is T, the ultrasonic wave between the ultrasonic transceivers 13 and 14 when the fluid to be measured is flowing is T. The transmission times Tau and Tad of the acoustic beam are
Tau = T-α
Tad = T + β
Can be considered. In this case, α and β are times generated by the flow in the forward direction AU and the reverse direction AD of the fluid to be measured, respectively.

Therefore, from the above formula, when the time difference between the transmission times Tau and Tad of the ultrasonic beam between the ultrasonic transceivers 13 and 14 is taken,
| Tau−Tad | = | T−α− (T + β) | = | α + β |
It becomes.
Here, the time difference | α + β | is a value portion representing the flow velocity of the fluid to be measured.

  Accordingly, for example, when the time difference | α + β | becomes larger than a predetermined time (for example, the vibration period of the reception signal Sgr of the ultrasonic beam), the flow measurement calculation control unit 21 calculates the time difference | α + β | ( When the difference between n-1) and the currently calculated time difference | α + β | (n) differs by a predetermined time difference or more, the occurrence of a single jump is detected when the value of the time difference | α + β |

  Next, in S403, the flow rate measurement calculation control unit 21 relates to the execution of the flow rate measurement process in the previous measurement cycle ('n-1' in this case), and the flow rate Q (n-1) calculated in S30. ), The flow rate Q (n) calculated in S30 is subtracted from the flow rate measurement process in the current measurement cycle, and the absolute value | Q (n-1) −Q (n) | It is determined whether or not the amount is smaller than the amount ΔQ.

  Then, the flow rate measurement calculation control unit 21 does not have the absolute value | Q (n−1) −Q (n) | smaller than the predetermined fluctuation amount ΔQ, and the flow rate calculation calculation control unit 21 covers the difference between the previous measurement cycle and the current measurement cycle. If there is a large fluctuation in the flow velocity of the measurement fluid, a single wave jump occurs at least when measuring the forward propagation time Tau or measuring the reverse propagation time Tad in the current measurement cycle. The occurrence of a single wave jump is detected.

  Next, in S404, the flow measurement calculation control unit 21 performs the flow measurement process in the previous measurement cycle, and the pressure value P (() of the measured fluid acquired from the pressure sensor 16 that measures the pressure of the measured fluid. n-1) is subtracted from the pressure value P (n) of the fluid to be measured obtained from the pressure sensor 16 in accordance with the execution of the flow rate measurement process in the current measurement cycle, and the absolute value | P (n-1) It is determined whether or not −P (n) | is smaller than a predetermined fluctuation amount ΔP.

  Then, the flow rate measurement calculation control unit 21 does not have the absolute value | P (n−1) −P (n) | smaller than the predetermined fluctuation amount ΔP, and the flow rate measurement calculation control unit 21 covers the difference between the previous measurement cycle and the current measurement cycle. When there is a large fluctuation in the pressure of the measurement fluid, one wave jump occurs at least either when measuring the forward propagation time Tau or measuring the reverse propagation time Tad in the current measurement cycle. The occurrence of a single wave jump is detected.

  In any of S401 to S404, the flow measurement calculation control unit 21 executes the setting gain Gau / Gad adjustment processing shown in S800 as the setting gain adjustment processing unit 33 when the occurrence of a single wave jump is detected. To do.

  On the other hand, if the occurrence of a single wave jump is not detected in any of S401 to S404, the flow measurement calculation control unit 21 first performs the process shown in S405.

  In S405, the flow measurement calculation control unit 21 relates to the execution of the flow measurement process in the previous measurement cycle, and the flow rate in the current measurement cycle from the forward propagation time Tau (n-1) measured in S10. In the execution of the measurement process, the forward propagation time Tau (n) measured in S10 is subtracted, and the absolute value | Tau (n-1) −Tau (n) | becomes larger than the predetermined time difference ΔTa. It is determined whether or not.

  If the absolute value | Tau (n−1) −Tau (n) | is greater than the predetermined time difference ΔTa in S405, the flow measurement calculation control unit 21 performs the process of S406.

  In S406, the flow measurement calculation control unit 21 is internally configured with a FIFO (First-In First-Out) memory or the like, and performs flow measurement processing for each measurement cycle for the latest predetermined number of times (for example, n times). In the current measurement cycle, the one-wave jump occurrence sign flag storage unit (not shown) Fau stores the sign (possibility) of the occurrence of one-wave jump at the time of measurement of the forward propagation time Tau for each execution in a first-in first-out manner. The flag Fau (n) = 1 is stored as data indicating that the measurement of the propagation time Tau performed may cause one wave jump.

  On the other hand, when the absolute value | Tau (n−1) −Tau (n) | is equal to or smaller than the predetermined time difference ΔTa, the flow measurement calculation control unit 21 performs the process of S407.

  In S407, the flow measurement calculation control unit 21 stores in the occurrence sign flag storage unit (not shown) Fau that the measurement of the propagation time Tau executed in the current measurement cycle has no possibility of occurrence of a single jump. As a result, the flag Fau (n) = 0 is stored.

  Therefore, the occurrence sign flag storage unit Fau of the flow measurement calculation control unit 21 has a possibility of occurrence of a single jump for each measurement of the propagation time Tau for each measurement cycle for the latest predetermined number of times (for example, n times). None is flag Fau (n) = 1 or flag Fau (n) = 0, and updates are accumulated at any time.

  In S <b> 408, the flow measurement calculation control unit 21 relates to the execution of the flow measurement process in the previous measurement cycle, and the flow rate in the current measurement cycle from the reverse propagation time Tad (n−1) measured in S <b> 20. In the execution of the measurement process, the reverse propagation time Tad (n) measured in S20 is subtracted, and the absolute value | Tad (n-1) −Tad (n) | becomes larger than the predetermined time difference ΔTd. It is determined whether or not.

  When the absolute value | Tad (n−1) −Tad (n) | is greater than the predetermined time difference ΔTd in S408, the flow measurement calculation control unit 21 performs the process of S409.

  In S409, the flow measurement calculation control unit 21 is configured with a FIFO (First-In First-Out) memory or the like, and performs flow measurement processing for each measurement cycle for the latest predetermined number of times (for example, n times). In the current measurement cycle, the one-wave jump occurrence sign flag storage unit (not shown) Fad that stores the sign (possibility) of the occurrence of one-wave jump at the time of measuring the propagation time Tad in the reverse direction for each execution is stored in a first-in first-out manner. The flag Fad (n) = 1 is stored as data indicating that there is a possibility of the occurrence of a single jump in the measured propagation time Tad.

  On the other hand, when the absolute value | Tad (n−1) −Tad (n) | is equal to or smaller than the predetermined time difference ΔTd, the flow measurement calculation control unit 21 performs the process of S410.

  In S410, the flow measurement calculation control unit 21 stores in the occurrence sign flag storage unit (not shown) Fad that the measurement of the propagation time Tad executed in the current measurement cycle has no possibility of occurrence of a single wave jump. As a result, the flag Fad (n) = 0 is stored.

  Therefore, the occurrence sign flag storage unit Fad of the flow measurement calculation control unit 21 has a possibility of occurrence of a single wave jump for each measurement of the propagation time Tad for each latest measurement cycle (for example, n times). None is flag Fad (n) = 1 or flag Fad (n) = 0, and updates are accumulated at any time.

  In S411, the flow measurement calculation control unit 21 performs one wave jump for each of the measurement of the propagation times Tau and Tad for the latest predetermined number of times (for example, n times) for each occurrence sign flag storage unit Fau and Fad. Counting and calculating how many measurement periods in which the flags Fau (n) = 1 and Fad (n) = 1 are stored are considered to be generated.

  In S412, the flow measurement calculation control unit 21 sets the number of Fau flags or the number of Fad flags, which is the number of measurement cycles calculated (ie, the number of executions of flow measurement processing), for each occurrence sign flag storage unit Fau, Fad. When both the Fau flag count and the Fad flag count are smaller than the predetermined number N compared with the predetermined number N set in advance, it is estimated that one wave jump has not occurred, and one wave jump detection processing is performed. Then, the flow shifts to the output process of the flow rate Q shown in S50 of the flow rate measurement process described in FIG.

  On the other hand, the flow measurement calculation control unit 21 estimates that one wave jump has occurred when either the number of Fau flags or the number of Fad flags is larger than the predetermined number N in S412. Detect the occurrence of

  When the occurrence of a single wave jump is detected in S412, the flow measurement calculation control unit 21 executes the setting gain Gau / Gad adjustment processing shown in S800 as the setting gain adjustment processing unit 33.

  As described above, the flow measurement calculation control unit 21 inherently performs the single jump detection processing such as S401, S402, S403, S404, S405 to S412 as the single jump detection processing unit 32 as described above. The occurrence of a single wave jump that could not be recognized during flow measurement of the fluid to be measured can be detected in many ways from temporal or physical fluctuations of the fluid to be measured. Guarantees accurate flow measurement.

  In the present embodiment, the flow measurement calculation control unit 21 performs the set gain Gau / Gad adjustment process shown in S800 as it is when the occurrence of a single jump is detected in the single jump detection process. In this transition, it is configured to output a single jump detection notification signal, and the ultrasonic flowmeter 1 is in a state of occurrence of a single jump to a worker in the field or a management office. You may comprise so that this may be notified.

  Next, the set gain Gau / Gad adjustment process executed by the flow measurement calculation control unit 21 as the set gain adjustment processing unit 33 in S800 of the one-wave jump detection process will be described with reference to FIG.

  The set gain Gau / Gad adjustment processing is different from the normal gain adjustment setting processing during flow rate measurement described in S60 in FIG. 2 performed by the flow rate measurement calculation control unit 21 as the set gain adjustment processing unit 33. The predetermined nth wave (second wave in FIG. 6) of the received signal Sgr and the peak voltage value Vpn of the nth wave can be identified and acquired from the received signal Sgr of the ultrasonic beam during flow rate measurement. Since this is not possible, the procedure is different as described below.

FIG. 5 is a flowchart of the setting gain Gau / Gad adjustment processing executed by the flow measurement calculation control unit as the setting gain adjustment processing unit.
In FIG. 5, the processes shown in S801 to S812 are performed for each adjustment process of the set gain Gau and the set gain Gad. Here, a case where the set gain Gau is adjusted and set will be described. The adjustment / setting is the same as the adjustment / setting of the setting gain Gau, and the details thereof will be omitted.

  When the adjustment process of the setting gain Gau is started in the setting gain Gau / Gad adjustment process by the flow measurement calculation control unit 21, the flow measurement calculation control unit 21 initially sets the forward gain Gau setting unit 26 in S801. The minimum gain GL is stored as the gain.

  Next, in S802, the flow measurement calculation control unit 21 sets the ultrasonic beam transmitting side as the upstream ultrasonic transmitter / receiver 13 in the flow direction of the fluid to be measured, and the receiving side as the downstream side in the flow direction of the fluid to be measured. The transmission / reception side switching unit 24 and the gain switching unit 25 are switched so that the ultrasonic beam is transmitted / received in the forward direction with respect to the flow direction of the fluid to be measured between the ultrasonic transmitters / receivers 13 and 14. Do.

  Thereby, the reception output of the ultrasonic beam by the ultrasonic transmitter / receiver 14 on the downstream side is stored by the reception signal amplification unit 23 in the forward gain Gau stored in the forward gain Gau setting unit 26, in this case, in S801. Amplified with the lowest gain GL, and is included in the ultrasonic beam reception output of the downstream ultrasonic transmitter / receiver 14 amplified with the lowest gain GL, as described with reference to FIG. A reception signal Sgr of the ultrasonic beam in which the periodic vibration is generated is supplied to the flow measurement calculation control unit 21.

  Next, in S803, the flow measurement calculation control unit 21 measures the maximum value Vp (the time point indicated by x in FIG. 6A) of the received ultrasonic beam reception signal Sgr. At this point in time, it is unknown what number wave included in the ultrasonic wave reception signal Sgr corresponds to the signal wave including the maximum value Vp.

  Next, in step S804, the flow measurement calculation control unit 21 sets the maximum value (maximum peak voltage) Vp of the acquired ultrasonic beam reception signal Sgr to a preset initial gain adjustment voltage value Vaji (FIG. 6 ( In (A), it is confirmed whether or not (corresponding to Vmx) has been reached. This initial gain adjustment voltage value Vaji is a voltage value set in advance separately from the gain adjustment output value Vaj used in the normal gain adjustment setting process (FIG. 2, S60, S70) during the flow rate measurement process. is there. That is, the gain adjustment output value Vaj is used for gain adjustment used for a predetermined nth wave after the predetermined nth wave (second wave in FIG. 6) of the received signal Sgr of the ultrasonic beam can be identified. Although it is a voltage value, the initial gain adjustment voltage value Vaji is the number of waves in a state where the predetermined n-th wave (second wave in FIG. 6) of the reception signal Sgr of the ultrasonic beam has not yet been identified. It is a voltage value for gain adjustment used for the maximum value Vp of the received signal Sgr, which can be identified regardless of whether it is present. For example, for the initial gain adjustment voltage value Vaji, the peak voltage value Vpn of the nth wave (second wave in FIG. 6) is set to a predetermined nth wave (2 in FIG. 6) by the measurement processing of the propagation time Tau of the ultrasonic beam. Used for identifying a preset voltage threshold value Vth used for identifying the wave wave) and the peak voltage value Vpn of the identified n wave (second wave in FIG. 6) in the normal gain adjustment setting process. It is set to the voltage value of the maximum peak voltage Vp of the ultrasonic beam reception signal Sgr, which corresponds to a case where adjustment is made to be between the gain adjustment output value Vaj. In other words, if the initial gain is adjusted so that the voltage value of the maximum peak voltage Vp of the reception signal Sgr of the ultrasonic beam is adjusted to the initial gain adjustment voltage value Vaji, the predetermined nth wave (the second wave in FIG. 6). ) And a normal gain adjustment setting that is set in advance so that the peak voltage value Vpn is between the n-th peak voltage value Vpn and the (n-1) th peak voltage value Vpn-1. The gain is adjusted to a value between the gain adjustment output value Vaj used in the processing.

  Next, in S805, if the maximum value Vp of the ultrasonic beam reception signal Sgr does not reach the initial gain adjustment voltage value Vaji in S804, the flow measurement calculation control unit 21 sends the forward gain Gau setting unit 26 to it. The amplification factor increased by one step in the adjustment unit from the currently stored value of the forward gain Gau is updated and stored in the forward gain Gau setting unit 26, and the processes shown in S802 to S804 are performed.

  Therefore, the flow measurement calculation control unit 21 sets the initial gain adjustment voltage value in which the maximum value Vp of the ultrasonic beam reception signal Sgr included in the ultrasonic beam reception output by the downstream ultrasonic transceiver 14 is preset. Until Vaji is reached, the value of the forward gain Gau stored in the forward gain Gau setting unit 26 is sequentially increased by one step for each transmission / reception of the ultrasonic beam shown in S802. In this embodiment, the forward gain Gau is adjusted by a predetermined adjustment unit so that the maximum value Vp of the ultrasonic beam reception signal Sgr is adjusted to the initial gain adjustment voltage value Vaji. However, instead of this, the maximum value Vp becomes the initial gain adjustment voltage value Vaji from the maximum value Vp of the ultrasonic beam reception signal Sgr and the initial gain adjustment voltage value Vaji. The forward gain Gau may be adjusted using an amplification factor obtained by calculating the direction gain Gau.

  When the flow measurement calculation control unit 21 confirms in S804 that the maximum value Vp of the ultrasonic beam reception signal Sgr has reached the initial gain adjustment voltage value Vaji, the confirmation is based on the time of the fluid to be measured. Alternatively, it is confirmed by the processing from S806 onward whether or not the physical adjustment has occurred and the spot adjustment has been performed.

  First, in S806, in preparation for this confirmation, the flow measurement calculation control unit 21 resets the count values Cn and Cm of the transmission / reception number counter Cn and the arrival number counter Cm formed in the internal memory to zero.

  Here, the transmission / reception number counter C is for counting the number of transmission / reception of the ultrasonic beam in the forward direction with respect to the flow direction of the fluid to be measured between the ultrasonic transmission / reception units 13 and 14, and the arrival number counter Cm is a predetermined number. This is for counting the number of times that the maximum value Vp of the ultrasonic beam reception signal Sgr reaches the initial gain adjustment voltage value Vaji in the transmission / reception of the ultrasonic beam N times.

  In step S <b> 807, the flow measurement calculation control unit 21 transmits and receives the ultrasonic beam in the forward direction with respect to the flow direction of the fluid to be measured between the ultrasonic transmitters and receivers 13 and 14.

  In S808, the flow measurement calculation control unit 21 determines whether or not the maximum value Vp of the ultrasonic beam reception signal Sgr acquired by the transmission / reception of the ultrasonic beam reaches a preset initial gain adjustment voltage value Vaji. Confirm.

  In S809, when the maximum value Vp of the ultrasonic beam reception signal Sgr reaches the initial gain adjustment voltage value Vaji, the flow measurement calculation control unit 21 increments the count value Cm of the arrival number counter Cm.

  In S810, the flow measurement calculation control unit 21 increments the count value Cn of the transmission / reception frequency counter Cn.

  In S811, the flow measurement calculation control unit 21 checks whether or not the count value Cn of the transmission / reception frequency counter Cn has reached the predetermined number N. As a result of this confirmation, the flow measurement calculation control unit 21 does not transmit / receive the ultrasonic beam in the forward direction with respect to the flow direction of the fluid to be measured between the ultrasonic transmitters / receivers 13 and 14 a predetermined number of times N. While repeating the process of confirming the value of the forward gain Gau updated and stored in the forward gain Gau setting unit 26 according to S807 to S811, the process of confirming the value of the forward gain Gau is performed a predetermined number of times N. Is completed, the value of the forward gain Gau is evaluated.

  In S812, the flow measurement calculation control unit 21 performs the evaluation by transmitting and receiving the count value Cm of the arrival number counter Cm a predetermined number of times N, and the maximum number of ultrasonic beam reception signals Sgr is greater than or equal to the predetermined number M. This is performed based on whether or not the value Vp has reached the initial gain adjustment voltage value Vaji.

  Then, the flow measurement calculation control unit 21 further adjusts the value of the forward gain Gau that is updated and stored in the forward gain Gau setting unit 26 when the count value Cm of the arrival number counter Cm is lower than the predetermined number M. If necessary, the process returns to S805 again to finely adjust the value of the forward gain Gau. On the other hand, if the count value Cm of the arrival number counter Cm is higher than the predetermined number M, the adjustment / setting is completed with the value of the forward gain Gau updated and stored in the forward gain Gau setting unit 26 in S805. To do.

  The case where the setting gain Gau is adjusted / set has been described above. However, when the setting gain Gad is adjusted / set, the flow rate calculation calculation control is performed in the same procedure as when the setting gain Gau is adjusted / set. This is performed by the unit 21. In this case, the adjustment / setting of the setting gain Gad may be performed continuously by completing the adjustment / setting of the setting gain Gau, or the adjustment / setting of the setting gain Gau and the setting gain Gad may be performed in both cases. The transmission and reception of the sound beam may be performed in parallel so as not to overlap.

  Then, when the adjustment and setting of the set gain Gau and the set gain Gad are completed, the flow measurement calculation control unit 21 determines that there is “one wave jump” in the one wave jump detection process shown in S40 of FIG. As indicated, the flow measurement process is resumed.

  Thereby, in the ultrasonic flowmeter 1 of the present embodiment, if it is detected that a single wave jump has occurred, the ultrasonic beam reception signal Sgr is different from the normal gain adjustment setting process during flow measurement. It is assumed that the predetermined n-th wave (second wave in FIG. 6) and the peak voltage value Vpn of the n-th wave cannot be identified and acquired from the received signal Sgr of the ultrasonic beam during flow rate measurement. The set gains Gau and Gad adjustment processing is automatically performed, and the propagation times Tau and Tad are erroneously measured due to inaccurate set gains Gau and Gad. Measurement can be prevented and the accurate flow rate Q of the fluid to be measured can be measured.

  Although the ultrasonic flowmeter 1 according to the present embodiment is as described above, it detects that a single wave jump has occurred based on temporal or physical fluctuations of the fluid to be measured, and controls the flow measurement calculation. If the unit 21 performs a setting gain Gau / Gad adjustment process that does not depend on detection of a predetermined n-th wave of the reception signal Sgr of the ultrasonic beam, the specific configuration is not limited to the above-described configuration. Various modifications can be applied.

1 Ultrasonic flow meter, 10 Flow meter body, 11 Measurement flow path,
12 measurement pipelines, 13, 14 ultrasonic transceivers,
15 propagation path, 16 pressure sensor, 20 flow measurement and calculation device,
21 flow measurement calculation control unit, 22 drive signal output unit,
23 reception signal amplification unit, 24 transmission / reception side switching unit,
25 gain switching unit, 26 forward gain Gau setting unit,
27 reverse gain Gad setting unit, 31 flow rate measurement processing unit,
32 a single wave jump detection processing unit, 33 a set gain adjustment processing unit.

Claims (7)

A pair of ultrasonic transmitters / receivers provided in the measurement flow path through which the fluid to be measured flows and the positions of the fluids to be measured are shifted along the flow direction;
A predetermined peak voltage of a predetermined wave in a reception signal of an ultrasonic beam transmitted from an ultrasonic transmitter / receiver on the transmission side of the pair of ultrasonic transmitter / receivers and received by an ultrasonic transmitter / receiver on the reception side is predetermined. An amplification factor calculating means for calculating the amplification factor of the received signal so as to be a voltage;
Amplifying means for amplifying the received signal by the receiving-side ultrasonic transmitter / receiver at the gain calculated by the gain calculating means;
The transmission side and the reception side are changed between the pair of ultrasonic transmitters and receivers so that the ultrasonic beam is transmitted and received in each of the forward and reverse directions with respect to the direction of the flow of the fluid to be measured. The predetermined signal in the received signal of the ultrasonic beam received by the ultrasonic transmitter / receiver on the receiving side according to the change between the transmitting side and the receiving side between the pair of ultrasonic transmitter / receivers and amplified by the amplifying means A flow rate calculation means for measuring the propagation time in each of the forward and reverse directions with respect to the direction of the flow of the fluid to be measured, and calculating the flow rate of the fluid to be measured from the both propagation times;
When a temporal or physical variation of the fluid to be measured is detected, and the variation is detected, the amplification factor is calculated by the amplification factor calculation means, and the peak of the predetermined wave when the variation is not detected. In place of the procedure for directly adjusting the voltage, an amplification factor calculation control means for performing the procedure for indirectly adjusting the maximum peak voltage of the reception signal of the ultrasonic beam including the predetermined wave is provided. Ultrasonic flow meter. The amplification factor calculation control means includes
Until an ultrasonic beam is transmitted from one upstream ultrasonic transmitter / receiver to the other downstream ultrasonic transmitter / receiver, measured by the flow rate calculation means, between the pair of ultrasonic transmitters / receivers Propagation time in the forward direction with respect to the flow direction of the fluid to be measured and from the time when the ultrasonic beam is transmitted from the other ultrasonic transmitter / receiver to the time when the ultrasonic transmitter / receiver is received by one upstream And a fluctuation detector for detecting temporal or physical fluctuations of the fluid to be measured when the difference between the propagation time in the reverse direction with respect to the flow direction of the fluid to be measured is a predetermined time difference or more. The ultrasonic flowmeter according to claim 1. The amplification factor calculation control means includes
Until an ultrasonic beam is transmitted from one upstream ultrasonic transmitter / receiver to the other downstream ultrasonic transmitter / receiver, measured by the flow rate calculation means, between the pair of ultrasonic transmitters / receivers Propagation time in the forward direction with respect to the flow direction of the fluid to be measured and from the time when the ultrasonic beam is transmitted from the other ultrasonic transmitter / receiver to the time when the ultrasonic transmitter / receiver is received by one upstream A fluctuation detector for detecting temporal or physical fluctuations of the fluid to be measured when the sum of the propagation time in the reverse direction with respect to the flow direction of the fluid to be measured does not coincide with the predetermined time The ultrasonic flowmeter according to claim 1. The predetermined time is determined by changing the transmission side and the reception side between the pair of ultrasonic transmitters / receivers before the ultrasonic beam in each of the forward direction and the reverse direction with respect to the flow direction of the fluid to be measured. 4. The super value according to claim 3, wherein the transmission time is a sum of propagation times in the forward direction and the reverse direction with respect to the direction of the flow of the fluid to be measured, which is measured by the flow rate calculation means when transmission / reception is performed. Sonic flow meter. The amplification factor calculation control means includes
When the flow rate difference between the previous flow rate and the current flow rate calculated by the flow rate calculation unit is larger than a predetermined flow rate difference, or the flow rate change rate between the previous flow rate and the current flow rate is predetermined. The ultrasonic flowmeter according to claim 1, further comprising a fluctuation detecting unit that detects temporal or physical fluctuation of the fluid to be measured when the rate of change is higher than the predetermined flow rate change rate. The amplification factor calculation control means includes
The pressure difference between the detected pressure at the previous acquisition and the pressure at the current acquisition, which is acquired from the pressure detector that detects the pressure of the fluid to be measured provided in the measurement channel, is greater than a predetermined pressure difference. If the pressure change rate between the detected pressure at the previous acquisition and the pressure at the current acquisition is higher than a predetermined pressure change rate determined in advance, the temporal or physical variation of the fluid to be measured is detected. The ultrasonic flowmeter according to claim 1, further comprising a fluctuation detection unit. The amplification factor calculation control means includes
The ultrasonic beam is transmitted from one upstream ultrasonic transmitter / receiver between the pair of ultrasonic transmitters / receivers measured this time and the previous time by the flow rate calculation means to the other downstream ultrasonic transmitter / receiver. When the propagation time difference between the forward propagation times is larger than the predetermined propagation time difference with respect to the flow direction of the fluid to be measured until reception, or an ultrasonic beam is transmitted from the other ultrasonic transmitter / receiver on the other downstream side When the propagation time difference between the propagation times in the reverse direction to the direction of the flow of the fluid to be measured from when it is received by the ultrasonic transmitter / receiver on one upstream side is larger than the predetermined propagation time difference, The ultrasonic flowmeter according to claim 1, further comprising: a fluctuation detecting unit that detects temporal or physical fluctuations.

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