WO2019049658A1 - Flow rate measuring device - Google Patents

Flow rate measuring device Download PDF

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WO2019049658A1
WO2019049658A1 PCT/JP2018/030887 JP2018030887W WO2019049658A1 WO 2019049658 A1 WO2019049658 A1 WO 2019049658A1 JP 2018030887 W JP2018030887 W JP 2018030887W WO 2019049658 A1 WO2019049658 A1 WO 2019049658A1
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propagation time
flow rate
unit
ultrasonic transducer
measurement abnormality
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PCT/JP2018/030887
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French (fr)
Japanese (ja)
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昭裕 伊佐地
光男 横畑
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パナソニックIpマネジメント株式会社
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01FMEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66Measuring 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

Abstract

This flow rate measuring device is provided with: a propagation time calculating unit (15) which measures a propagation time of ultrasound waves between a first ultrasonic transducer (2) and a second ultrasonic transducer (3) a certain number of times to obtain an averaged forward direction upstream side propagation time and an averaged reverse direction downstream side propagation time; and a measurement abnormality determining unit (16) which determines a propagation time measurement abnormality. The measurement abnormality determining unit (16) determines the measurement abnormality on the basis of the current value C1(n) of the upstream side propagation time, the previous value C1(n-1) of the upstream side propagation time, the current value C2(n) of the downstream side propagation time and the previous value C2 (n-1) of the downstream side propagation time.

Description

流量計測装置Flow measurement device
 本発明は超音波を利用してガスなどの流体の流れを計測する流量計測装置に関するもので、ノイズによる計測異常を判定する機能を有する流量計測装置である。 The present invention relates to a flow rate measuring device which measures the flow of fluid such as gas using ultrasonic waves, and is a flow rate measuring device having a function of determining measurement abnormality due to noise.
 従来のこの種の流体の流量計測装置構成は、図7に示す構成が一般的であった。 The conventional flow rate measuring device configuration of this kind of fluid is generally the configuration shown in FIG.
 この流量計測装置は流体の流れる流路121に設置した第1超音波振動子122および第2超音波振動子123と、第1超音波振動子122、第2超音波振動子123の送受信を切り換える切換部124とを備えている。さらに、この流量計測装置は第1超音波振動子122および第2超音波振動子123を駆動する送信部125と、受信側の超音波振動子で受信し切換部124を通過した受信信号を所定の振幅まで増幅する増幅部126と、増幅部126で増幅された受信信号の電圧と基準電圧とを比較する基準比較部127とを備えている。 This flow rate measuring apparatus switches between transmission and reception of the first ultrasonic transducer 122 and the second ultrasonic transducer 123, and the first ultrasonic transducer 122 and the second ultrasonic transducer 123 installed in the fluid flow path 121. A switching unit 124 is provided. Further, the flow rate measuring apparatus is configured to transmit the first ultrasonic transducer 122 and the second ultrasonic transducer 123, and the reception signal received by the receiving ultrasonic transducer and passed through the switching unit 124. And a reference comparison unit 127 that compares the voltage of the received signal amplified by the amplification unit 126 with a reference voltage.
 図8は、受信信号からゼロクロス点の判定を行う方法を説明するための動作説明図である。図8に示すように、この流量計測装置は基準比較部127で増幅後の受信信号Aと基準電圧Vrを比較し基準電圧Vrより受信信号Aが大きくなった時(タイミングc)に出力される出力信号Cから後の受信信号のゼロクロス点aを検知する判定部128を備えている。さらに、この流量計測装置は、この判定部128で検知した時に出力される信号出力Dのタイミングから超音波の送受信の伝播時間を計時する計時部129と、送信部125や増幅部126の制御を行い、計時部129の計時した時間に基づいて流速および/または流量を算出する制御部130とを備えている。 FIG. 8 is an operation explanatory diagram for describing a method of determining the zero crossing point from the received signal. As shown in FIG. 8, the flow rate measuring apparatus compares the amplified received signal A with the reference voltage Vr in the reference comparing section 127 and outputs it when the received signal A becomes larger than the reference voltage Vr (timing c). A determination unit 128 is provided to detect the zero cross point a of the received signal after the output signal C. Furthermore, the flow rate measuring device controls the time measuring unit 129 that measures the propagation time of transmission and reception of ultrasonic waves from the timing of the signal output D output when detected by the determining unit 128, and controls the transmitting unit 125 and the amplifying unit 126. And a control unit 130 that calculates the flow velocity and / or the flow rate based on the time counted by the timer unit 129.
 この構成において、受信信号Aの4波目を検出できる電圧に基準電圧Vrを設定しておくことで、常に4波目を検出することができる。 In this configuration, by setting the reference voltage Vr to a voltage that can detect the fourth wave of the reception signal A, it is possible to always detect the fourth wave.
 この装置は制御部130により送信部125を動作させ第1超音波振動子122で発信された超音波信号が、流体の流れの中を伝播し第2超音波振動子123で受信され、増幅部126で増幅後、基準比較部127と判定部128で信号処理され、計時部129に入力される。 In this apparatus, the control unit 130 causes the transmitting unit 125 to operate, and the ultrasonic signal transmitted by the first ultrasonic transducer 122 propagates in the flow of fluid and is received by the second ultrasonic transducer 123, and the amplifying unit After amplification at 126, the signal is processed by the reference comparison unit 127 and the determination unit 128, and is input to the clock unit 129.
 次に、切換部124により第1超音波振動子122と第2超音波振動子123とを切り替えて、第2超音波振動子123で発信された超音波信号が流体の流れの中を伝播し、第1超音波振動子122で受信されるという動作を行う。この2つの動作により、被測定流体の上流から下流(この方向を正流とする)に向かって伝播する超音波信号の伝播時間と、下流から上流(この方向を逆流とする)に向かって伝播する超音波信号の伝播時間を計時部129により測定する。 Next, the first ultrasonic transducer 122 and the second ultrasonic transducer 123 are switched by the switching unit 124, and the ultrasonic signal transmitted by the second ultrasonic transducer 123 propagates in the fluid flow. , And received by the first ultrasonic transducer 122. By these two operations, the propagation time of the ultrasonic signal propagating from upstream to downstream (this direction is referred to as the forward flow) of the fluid to be measured, and from the downstream to upstream (this direction is referred to as the backward flow) The measuring unit 129 measures the propagation time of the ultrasonic signal.
 ここで、第1超音波振動子と第2超音波振動子の間の流れ方向の有効距離をL、上流から下流への伝播時間をt1、下流から上流への伝播時間をt2、被測定流体の流速をv、流路の断面積をS、センサ角度をφとすると、流量Qは次式で求めることができる。 Here, the effective distance in the flow direction between the first ultrasonic transducer and the second ultrasonic transducer is L, the propagation time from upstream to downstream is t1, the propagation time from downstream to upstream is t2, and the fluid to be measured The flow rate Q can be determined by the following equation, where v is the flow velocity of the flow path, S is the cross-sectional area of the flow path, and φ is the sensor angle.
 Q=S・v=S・L/2・cosφ(n/t1-n/t2) ・・・式(A)
 実際には、式(A)に流量に応じた係数をさらに乗じて流量を算出する。
Q = S · v = S · L / 2 · cos φ (n / t 1-n / t 2) formula (A)
In practice, the flow rate is calculated by further multiplying the equation (A) by a coefficient corresponding to the flow rate.
 そして、何らかのノイズにより受信波形に歪みが生じるなどで正確な超音波信号の伝播時間の計測ができなかったことを検出する流量計測装置である超音波流量計が提案されている。すなわち、前回と今回の超音波信号の伝播時間の差分が超音波受信信号の波長に等しい場合には、正規の波(図8の4波目)を検出できずに前後の波(図8の3波や5波)を検出したとして誤計測であると判定する誤計測判定部を有する超音波流量計が提案されている(例えば、特許文献1参照)。 Then, an ultrasonic flowmeter has been proposed which is a flow rate measuring device for detecting that an accurate measurement of the propagation time of the ultrasonic signal could not be performed due to distortion of the received waveform due to some noise or the like. That is, when the difference in propagation time between the previous and current ultrasonic signals is equal to the wavelength of the ultrasonic wave reception signal, the normal wave (fourth wave in FIG. 8) can not be detected, and the front and rear waves (FIG. 8) There has been proposed an ultrasonic flowmeter having an erroneous measurement determination unit that determines that erroneous measurement has occurred because three waves or five waves are detected (for example, see Patent Document 1).
特開2014-224685号公報JP 2014-224685 A
 しかしながら、特許文献1に開示された、流量計測装置である超音波流量計の構成では、前回と今回の伝播時間の差分が超音波受信信号の波長に等しい場合のみ誤計測と判定するため、伝播時間を計測するゼロクロスのタイミングがノイズにより変化するような場合は、誤計測と判定することでできないという課題が有った。 However, in the configuration of the ultrasonic flowmeter, which is a flow rate measuring device, disclosed in Patent Document 1, propagation is determined as erroneous measurement only when the difference between the previous and current propagation times is equal to the wavelength of the ultrasonic wave reception signal. When the timing of the zero crossing to measure time changes due to noise, there is a problem that it can not be determined as an erroneous measurement.
 本発明は、外乱等でノイズが混入し受信波形に大きな歪が生じてゼロクロス点がずれるような場合でも、精度よくノイズによる計測異常と判定することができる流量計測装置を提供する。 The present invention provides a flow rate measuring apparatus capable of accurately determining as a measurement abnormality due to noise even when noise is mixed due to disturbance or the like to cause large distortion in a received waveform and the zero cross point is shifted.
 本発明の流量計測装置は、被測定流体の流れる流路の上流に配置され超音波を送受信する第1超音波振動子と、流路の下流に配置され超音波を送受信する第2超音波振動子と、第1超音波振動子および第2超音波振動子を駆動する送信部と、を備える。また、本発明の流量計測装置は、第1超音波振動子および第2超音波振動子の送受信を切り換える切換部と、第1超音波振動子または第2超音波振動子の受信信号を所定の振幅まで増幅する増幅部と、増幅部の出力と基準電圧とを比較する基準比較部と、を備える。また、本発明の流量計測装置は、基準比較部と増幅部の出力とから超音波信号の到達時期を判定する判定部と、判定部で判定した超音波信号の到達時期から超音波信号の送受信の伝播時間を計時する計時部と、を備える。また、本発明の流量計測装置は、第1超音波振動子から第2超音波振動子への超音波の伝播時間を所定回数計測して平均した上流側伝播時間と、第2超音波振動子から第1超音波振動子への超音波の伝播時間を所定回数計測して平均した下流側伝播時間と、を求める伝播時間演算部を備える。また、本発明の流量計測装置は、上流側伝播時間または下流側伝播時間の計測異常を判定する計測異常判定部と、上流側伝播時間と下流側伝播時間の時間差から流量を演算する流量演算部と、を備える。さらに、本発明の流量計測装置は、伝播時間演算部が、所定時間間隔で上流側伝播時間と下流側伝播時間を演算し、計測異常判定部が、上流側伝播時間の今回値C1(n)と上流側伝播時間の前回値C1(n-1)と下流側伝播時間の今回値C2(n)と下流側伝播時間の前回値C2(n-1)に基づき計測異常を判定する。 The flow rate measuring apparatus according to the present invention includes a first ultrasonic transducer disposed upstream of a flow channel through which a fluid to be measured flows and transmitting and receiving ultrasonic waves, and a second ultrasonic vibration disposed downstream of the flow channel transmitting and receiving ultrasonic waves And a transmitter configured to drive the first ultrasonic transducer and the second ultrasonic transducer. Further, in the flow rate measuring device according to the present invention, a switching unit for switching between transmission and reception of the first ultrasonic transducer and the second ultrasonic transducer, and a reception signal of the first ultrasonic transducer or the second ultrasonic transducer are predetermined. An amplification unit that amplifies to an amplitude, and a reference comparison unit that compares the output of the amplification unit with a reference voltage. In the flow rate measuring apparatus according to the present invention, the determination unit determines the arrival time of the ultrasound signal from the reference comparison unit and the output of the amplification unit, and the transmission and reception of the ultrasound signal from the arrival time of the ultrasound signal determined by the determination unit And a clock unit for clocking the propagation time of the Further, according to the flow rate measuring device of the present invention, the upstream side propagation time obtained by measuring and averaging the propagation times of ultrasonic waves from the first ultrasonic transducer to the second ultrasonic transducer a predetermined number of times, and the second ultrasonic transducer And a propagation time calculation unit for obtaining a downstream side propagation time obtained by measuring a propagation time of an ultrasonic wave from the second ultrasonic transducer to the first ultrasonic transducer a predetermined number of times and averaging them. Further, the flow rate measuring apparatus according to the present invention includes a measurement abnormality determination unit that determines measurement abnormality of upstream propagation time or downstream propagation time, and a flow rate computing unit that calculates flow rate from time difference between upstream propagation time and downstream propagation time. And. Furthermore, in the flow rate measuring apparatus according to the present invention, the propagation time calculation unit calculates the upstream propagation time and the downstream propagation time at predetermined time intervals, and the measurement abnormality determination unit calculates the current value C1 (n) of the upstream propagation time. The measurement abnormality is determined based on the previous value C1 (n-1) of the upstream side propagation time, the current value C2 (n) of the downstream side propagation time, and the previous value C2 (n-1) of the downstream side propagation time.
 この構成により、外乱等でノイズが混入し受信波形に大きな歪が生じてゼロクロス点がずれるような場合でも、精度よくノイズによる計測異常と判定することができる。 With this configuration, it is possible to accurately determine that the measurement is abnormal due to noise even when noise is mixed due to disturbance or the like to cause a large distortion in the received waveform and the zero cross point is shifted.
図1は、本発明の第1の実施の形態における流量計測装置の構成図である。FIG. 1 is a block diagram of a flow rate measuring apparatus according to a first embodiment of the present invention. 図2は、本発明の第1の実施の形態における流量計測装置の計測タイミングと伝播時間の計測方法を説明する図である。FIG. 2 is a diagram for explaining the measurement timing and propagation time measuring method of the flow rate measuring apparatus according to the first embodiment of the present invention. 図3は、ノイズにより受信波形に歪みが生じた場合の伝播時間の計測方法を説明するための動作説明図である。FIG. 3 is an operation explanatory diagram for explaining a method of measuring the propagation time when distortion occurs in the received waveform due to noise. 図4は、本発明の第1の実施の形態における流量計測装置の計測異常判定方法を説明する図である。FIG. 4 is a diagram for explaining a measurement abnormality determination method of the flow rate measuring apparatus according to the first embodiment of the present invention. 図5は、本発明の第1の実施の形態における流量計測装置の流量無しの場合の計測異常判定方法を説明する図である。FIG. 5 is a diagram for explaining a measurement abnormality determination method when there is no flow rate of the flow rate measurement device according to the first embodiment of the present invention. 図6は、本発明の第1の実施の形態における流量計測装置の流量有りの場合の計測異常判定方法を説明する図である。FIG. 6 is a diagram for explaining a measurement abnormality determination method in the case where there is a flow rate of the flow rate measurement device according to the first embodiment of the present invention. 図7は、従来の流量計測装置の構成図である。FIG. 7 is a block diagram of a conventional flow rate measuring device. 図8は、受信信号からゼロクロス点の判定を行う方法を説明するための動作説明図である。FIG. 8 is an operation explanatory diagram for describing a method of determining the zero crossing point from the received signal.
 以下、本発明の実施の形態について、図面を参照しながら説明する。なお、この実施の形態によって本発明が限定されるものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by the embodiment.
 (第1の実施の形態)
 本発明の第1の実施の形態について、図1~図4を用いて説明する。
First Embodiment
A first embodiment of the present invention will be described using FIG. 1 to FIG.
 図1は、本発明の第1の実施の形態における流量計測装置の構成図を示すものである。 FIG. 1 shows a block diagram of a flow rate measuring apparatus according to a first embodiment of the present invention.
 図1において、流量計測装置14は、被測定流体が流れる流路1の途中における上流に配置され超音波を送受信する第1超音波振動子2と、流路1の途中における下流に配置され超音波を送受信する第2超音波振動子3とが距離を置いて流路1の同じ面1b(図1では上面)に配置されている。 In FIG. 1, the flow rate measuring device 14 is disposed upstream in the middle of the flow path 1 through which the fluid to be measured flows, and transmits and receives ultrasonic waves. A second ultrasonic transducer 3 for transmitting and receiving sound waves is disposed on the same surface 1b (upper surface in FIG. 1) of the flow channel 1 at a distance.
 第1超音波振動子2と第2超音波振動子3は共に超音波の送信と受信の機能を備えている。切換部4によりその送信と受信の機能が選択され、送信の機能を選択された第1超音波振動子2又は第2超音波振動子3には、送信部5の出力信号が供給される切換部4により受信の機能を選択された第1超音波振動子2又は第2超音波振動子3で受信された超音波は超音波信号として受信部6に供給される。 The first ultrasonic transducer 2 and the second ultrasonic transducer 3 both have the functions of transmitting and receiving ultrasonic waves. The switching unit 4 selects the transmission and reception functions, and the first ultrasonic transducer 2 or the second ultrasonic transducer 3 whose transmission function is selected is supplied with the output signal of the transmitting unit 5. The ultrasonic waves received by the first ultrasonic transducer 2 or the second ultrasonic transducer 3 whose reception function has been selected by the unit 4 are supplied to the receiving unit 6 as ultrasonic signals.
 第1超音波振動子2が送信側に設定され、第2超音波振動子3が受信側に設定された場合、超音波は、図1の矢印A、Bで示すように、第1超音波振動子2から送信され、流路1の内壁1aに反射して第2超音波振動子3に到達する伝播経路をたどる。第1超音波振動子2が受信側に設定され、第2超音波振動子3が送信側に設定された場合、超音波は、図1の矢印A、Bで示す伝播経路とは逆の伝播経路をたどる。 When the first ultrasonic transducer 2 is set to the transmitting side and the second ultrasonic transducer 3 is set to the receiving side, as shown by arrows A and B in FIG. A propagation path which is transmitted from the transducer 2 and reflected by the inner wall 1 a of the flow path 1 and reaches the second ultrasonic transducer 3 is traced. When the first ultrasonic transducer 2 is set to the receiving side and the second ultrasonic transducer 3 is set to the transmitting side, the ultrasonic waves propagate in the opposite direction to the propagation paths shown by arrows A and B in FIG. Follow the path.
 受信部6に供給された超音波信号は受信信号として、次の増幅部7に送られ、増幅部7で受信信号の最大電圧値が所定の電圧範囲に入るように調整される。すなわち、受信部6に供給された受信信号を増幅部7が所定の振幅まで増幅する。なお、増幅部7における増幅率の調整方法は従来と同様であり説明は省略する。 The ultrasonic signal supplied to the receiving unit 6 is sent to the next amplification unit 7 as a reception signal, and is adjusted by the amplification unit 7 so that the maximum voltage value of the reception signal falls within a predetermined voltage range. That is, the amplification unit 7 amplifies the reception signal supplied to the reception unit 6 to a predetermined amplitude. The method of adjusting the amplification factor in the amplification unit 7 is the same as in the prior art, and the description thereof is omitted.
 基準比較部8は、増幅部7で増幅された受信信号と基準電圧設定部9で設定された基準電圧とを比較し信号を出力する。 The reference comparison unit 8 compares the reception signal amplified by the amplification unit 7 with the reference voltage set by the reference voltage setting unit 9 and outputs a signal.
 基準電圧設定部9は、受信信号の検知対象の波を検知できるように適切に基準電圧を設定するものであり、本実施の形態では検知対象の波を4波としており、従来と同様に増幅後の受信信号の3波のピークと4波のピークの中間の電圧に基準電圧を設定する。 The reference voltage setting unit 9 appropriately sets the reference voltage so that the detection target wave of the reception signal can be detected. In the present embodiment, four detection target waves are used, and amplification is performed as in the prior art. The reference voltage is set to an intermediate voltage between the three peaks and the four peaks of the later received signal.
 次に、基準比較部8の出力と増幅部7で増幅された受信信号とから超音波の到達時期が判定部10で判定され、計時部11は、判定部10で判定された超音波の到達時期から超音波の送受信の伝播時間を計時する。 Next, the arrival time of the ultrasonic wave is determined by the determination unit 10 from the output of the reference comparison unit 8 and the reception signal amplified by the amplification unit 7, and the time measurement unit 11 determines the arrival of the ultrasonic wave determined by the determination unit 10 Time the propagation time of the transmission and reception of ultrasonic waves from the time.
 伝播時間演算部15は後述する方法により、第1超音波振動子2から第2超音波振動子3への超音波の伝播時間である上流側伝播時間C1と、第2超音波振動子3から第1超音波振動子2への超音波の伝播時間である下流側伝播時間C2を求める。 The propagation time calculation unit 15 uses an upstream side propagation time C1 which is a propagation time of ultrasonic waves from the first ultrasonic transducer 2 to the second ultrasonic transducer 3 and a method from the second ultrasonic transducer 3 by a method described later. A downstream side propagation time C2 which is a propagation time of the ultrasonic wave to the first ultrasonic transducer 2 is determined.
 計測異常判定部16は、伝播時間演算部15で求めた伝播時間に基づいてノイズ等による計測異常の有無を判定する。 The measurement abnormality determination unit 16 determines the presence or absence of a measurement abnormality due to noise or the like based on the propagation time obtained by the propagation time calculation unit 15.
 なお、これら図1の点線で囲まれた各構成要素は、制御部13としてのマイクロコンピュータ等によって制御される。 The components enclosed by dotted lines in FIG. 1 are controlled by a microcomputer as the control unit 13 or the like.
 次に、図2を用いて伝播時間演算部15における上流側伝播時間C1と下流側伝播時間C2の計測方法を説明する。 Next, a method of measuring the upstream propagation time C1 and the downstream propagation time C2 in the propagation time calculation unit 15 will be described with reference to FIG.
 図2の(a)は流量計測のタイミングを示しており、所定時間T毎(本実施の形態では2秒周期)に伝播時間の計測とそれに基づく演算処理が行われる。この周期は、流量演算部12で流量を求める周期と同じである。図2の(b)は流量計測n-1番目(前回)とn番目(今回)における伝播時間の計測方法を示すもので、制御部13は、この1周期の2秒間に、切換部4により第1超音波振動子2および第2超音波振動子3の送受信を切り換えながら計時部11により上流から下流、下流から上流への伝播時間の計測を1組として、60組分の計測を行う。 (A) of FIG. 2 shows the flow measurement timing, and measurement of the propagation time and calculation processing based on it are performed every predetermined time T (in the present embodiment, a 2-second cycle). This cycle is the same as the cycle for obtaining the flow rate by the flow rate calculation unit 12. (B) of FIG. 2 shows a method of measuring the propagation time at flow measurement n-1st (previous time) and nth (current time), and the control unit 13 switches the switching unit 4 for 2 seconds of this one cycle. While switching between transmission and reception of the first ultrasonic transducer 2 and the second ultrasonic transducer 3, measurement of propagation time from upstream to downstream and from downstream to upstream by the timer unit 11 is performed as one set, and 60 sets of measurements are performed.
 そして、演算処理において、伝播時間演算部15は上流から下流への伝播時間の計測値60個を平均して上流側伝播時間C1を求め、同様に、下流から上流への伝播時間の計測値60個を平均して下流側伝播時間C2を求める。 Then, in the arithmetic processing, the propagation time calculation unit 15 averages 60 measured values of propagation time from upstream to downstream to obtain the upstream propagation time C1, and similarly, the measured value 60 of propagation time from downstream to upstream The downstream propagation time C2 is determined by averaging these.
 また、演算処理において、流量演算部12は伝播時間演算部15で求めた上流側伝播時間C1と下流側伝播時間C2を用い、前述の式(A)においてt1=C1、t2=C2として流量を算出し、積算部17は、流量演算部12で算出された流量を積算する。 Further, in the arithmetic processing, the flow rate operation unit 12 uses the upstream side propagation time C1 and the downstream side propagation time C2 obtained by the propagation time operation unit 15 and sets the flow rate as t1 = C1 and t2 = C2 in the above-mentioned formula (A). The integration unit 17 integrates the flow rate calculated by the flow rate calculation unit 12.
 以降の説明において、上流側伝播時間C1の今回と前回の値を区別する必要がある場合は、今回の値をC1(n)とし、前回の値をC1(n-1)と記載する。下流側伝播時間C2、その他についても同様の表示とする。 In the following description, when it is necessary to distinguish between the current value and the previous value of the upstream side propagation time C1, the current value is C1 (n), and the previous value is C1 (n-1). The same applies to the downstream propagation time C2 and the like.
 次に、計測異常判定部16における計測異常の判定方法を説明する。 Next, a method of determining measurement abnormality in the measurement abnormality determination unit 16 will be described.
 図3は、外部からのノイズが計測回路に侵入して受信波形の3波目に歪が生じた状態を示している。なお、波形に歪みを生じるようなノイズは常に発生するものではなく、本実施の形態においては計測周期の数回に1度起きる程度のノイズを想定して説明する。 FIG. 3 shows a state in which external noise enters the measurement circuit and distortion occurs in the third wave of the reception waveform. In addition, the noise which produces distortion in a waveform does not always generate | occur | produce, and it demonstrates supposing the noise of the extent which generate | occur | produces once in several times of a measurement period in this Embodiment.
 図に示すようにノイズで受信波形にひずみが生じ、本来受信すべき4波目より手前に基準電圧Vrを超える波形が発生した場合、基準比較部8は出力信号CCを出力し、判定部10は次のゼロクロス点aaを受信点と判断して出力信号DDを出力する。計時部11は、この出力信号DDに基づいて伝播時間を求めることになる。 As shown in the figure, when the reception waveform is distorted due to noise and a waveform exceeding the reference voltage Vr occurs before the fourth wave to be originally received, the reference comparison unit 8 outputs the output signal CC, and the determination unit 10 Determines the next zero crossing point aa as a receiving point and outputs an output signal DD. The timer unit 11 obtains the propagation time based on the output signal DD.
 図4は、図2に示す今回(n番目)の計測周期の下流から上流への60回の伝播時間計測の内、何れかの1つの計測中に図3に示すような歪が生じて計測時間が通常より短くなった場合の上流側伝播時間C1と下流側伝播時間C2の前回と今回の関係を説明するための説明図である。 FIG. 4 shows distortions as shown in FIG. 3 during measurement of any one of 60 propagation time measurements from downstream to upstream of the present (n-th) measurement cycle shown in FIG. It is explanatory drawing for demonstrating the last time of this time with the upstream propagation time C1 in case time becomes shorter than usual, and the downstream propagation time C2, and this time.
 図4において、今回の計測(n番目)では、60組計測された伝播時間の内、下流側から上流側への伝播時間計測の1つが図3に示す本来のゼロクロス点aの計測時間に対して時間tだけ短く計測されたために、下流側伝播時間C2(n)がX(=t/60)だけ前回に比べ短く算出されている。 In FIG. 4, in the present measurement (n-th), one of the propagation time measurement from the downstream side to the upstream side out of the 60 sets of measured propagation time is relative to the measurement time of the original zero crossing point a shown in FIG. The downstream side propagation time C2 (n) is calculated to be shorter by X (= t / 60) compared to the previous time because the measurement is made shorter by time t.
 まず、前回と今回における上流側伝播時間C1と下流側伝播時間C2の平均値Ave.C(n-1)、Ave.C(n)はそれぞれ次式で求めることができる。 First, the average value Ave. of the upstream side propagation time C1 and the downstream side propagation time C2 in the previous and current times is calculated. C (n-1), Ave. C (n) can be determined by the following equation.
 Ave.C(n-1)=(C1(n-1)+C2(n-1))/2 ・・・式(1)
 Ave.C(n)=(C1(n)+C2(n))/2 ・・・式(2)
 また、前回の平均値と今回の平均値との平均値Aveは、次式で求めることができる。
Ave. C (n-1) = (C1 (n-1) + C2 (n-1)) / 2 Formula (1)
Ave. C (n) = (C1 (n) + C2 (n)) / 2 Formula (2)
Further, an average value Ave of the previous average value and the current average value can be obtained by the following equation.
 Ave=(Ave.C(n-1)+Ave.C(n))/2 ・・・式(3)
ここで、式(1)、式(2)およびC1(n-1)=C1(n)、C2(n)=C2(n-1)-Xの関係から、
 Ave=(C1(n)+C2(n))/2+X/4 ・・・式(4)
 即ち、平均値Aveは、今回の上流側伝播時間C1(n)と下流側伝播時間C2(n)の平均値に下流側伝播時間の変化量X/4を加算した値となる。
Ave = (Ave. C (n-1) + Ave. C (n)) / 2 Formula (3)
Here, from the relationship of Formula (1), Formula (2) and C1 (n-1) = C1 (n), C2 (n) = C2 (n-1)-X,
Ave = (C1 (n) + C2 (n)) / 2 + X / 4 Formula (4)
That is, the average value Ave is a value obtained by adding the change amount X / 4 of the downstream side propagation time to the average value of the current upstream side propagation time C1 (n) and the downstream side propagation time C2 (n).
 従って、平均値Aveと今回の上流側伝播時間C1(n)との差分ΔC1は、
 ΔC1=C1(n)-Ave
    =(C1(n)-C2(n))/2-X/4 ・・・式(5)
また、平均値Aveと今回の下流側伝播時間C2(n)との差分ΔC2は、
 ΔC2=Ave-C2(n)
    =(C1(n)-C2(n))/2+X・3/4 ・・・式(6)
となる。
Therefore, the difference ΔC1 between the average value Ave and the current upstream propagation time C1 (n) is
ΔC1 = C1 (n) -Ave
= (C1 (n)-C2 (n)) / 2-X / 4 formula (5)
Also, the difference ΔC2 between the average value Ave and the current downstream propagation time C2 (n) is
ΔC2 = Ave-C2 (n)
= (C1 (n)-C2 (n)) / 2 + X · 3/4 formula (6)
It becomes.
 (流量無しの場合)
 図5は、図4において、流量がほぼゼロの場合の状態を示しており、この場合、C1(n)=C2(n)となるので、式(5)、式(6)から、ΔC1=-X/4、ΔC2=+X・3/4となり、|ΔC1|:|ΔC2|=1:3の関係が成り立つ。
(When there is no flow)
FIG. 5 shows a state in which the flow rate is substantially zero in FIG. 4. In this case, since C1 (n) = C2 (n), ΔC1 = from Equation (5) and Equation (6). It becomes −X / 4, ΔC2 = + X · 3/4, and the relationship of | ΔC1 |: | ΔC2 | = 1: 3 holds.
 従って、計測異常判定部16は、流量がほぼゼロの場合には、式(5)、式(6)により、差分ΔC1、ΔC2を演算し、|ΔC1|:|ΔC2|=1:3の関係が成り立つ場合、ノイズにより計測異常が発生していると判断することができる。 Therefore, when the flow rate is substantially zero, the measurement abnormality determination unit 16 calculates the differences ΔC1 and ΔC2 by the equations (5) and (6), and the relationship | ΔC1 |: | ΔC2 | = 1: 3 Is satisfied, it can be determined that a measurement error has occurred due to noise.
 なお、実際の判断においては、計測誤差等を考慮して、例えば、次式で示すように範囲で判定する。 Note that, in actual judgment, in consideration of a measurement error or the like, for example, judgment is made in a range as shown by the following expression.
 2.5≦|ΔC2|/|ΔC1|≦3.5 ・・・式(7)
 そして、この差分ΔC1、ΔC2は、上流側伝播時間の今回値C1(n)と前回値C1(n-1)、下流側伝播時間の今回値C2(n)と前回値C2(n-1)により、容易に求めることが可能であり、制御部13を構成するマイクロコンピュータにより容易に実現することができる。
2.5 ≦ | ΔC2 | / | ΔC1 | ≦ 3.5 (7)
The differences ΔC1 and ΔC2 are the current value C1 (n) and the previous value C1 (n-1) of the upstream propagation time, and the current value C2 (n) and the previous value C2 (n-1) of the downstream propagation time. Therefore, it can be easily obtained, and can be easily realized by the microcomputer configuring the control unit 13.
 また、積算部17は、計測異常判定部16で計測異常が発生していると判断された場合には、流量演算部12で計測された流量を積算しないようにすることで、流量が流れていない場合に誤って積算することを防止することができる。 In addition, when the measurement abnormality determination unit 16 determines that the measurement abnormality is occurring, the integration unit 17 prevents the integration of the flow rate measured by the flow rate calculation unit 12 so that the flow rate flows. It is possible to prevent erroneous integration when there is no.
 なお、本実施の形態では、下流側伝播時間がノイズによる影響で短くなった場合で説明したが、上流側伝播時間がノイズによる影響で短くなった場合でも同様であることは言うまでも無い。この場合、式(7)おいて、分子と分母を入れ替える。 In the present embodiment, although the downstream propagation time has been shortened due to the influence of noise, it goes without saying that the same is true even when the upstream propagation time is shortened due to the influence of noise. In this case, the numerator and denominator are interchanged in equation (7).
 (流量有りの場合)
 式(5)、式(6)から分かるように、流量が大きく(C1(n)-C2(n))/2に対して、X/4が無視できる程小さい場合には、ΔC1(n):ΔC2(n)≒1:1となる。従って、流量が大きい場合には、ノイズ判定を行う必要はないが、X/4が無視できない場合の流量域における判定方法を次に説明する。
(When there is a flow)
As can be seen from the equations (5) and (6), if the flow rate is large and the X / 4 is negligible with respect to (C1 (n) -C2 (n)) / 2, ΔC1 (n) : ΔC 2 (n) ≒ 1: 1. Therefore, when the flow rate is large, it is not necessary to perform the noise determination, but the determination method in the flow rate range when X / 4 can not be ignored will be described below.
 図6は、図4において前回の上流側伝播時間C1(n-1)と下流側伝播時間C2(n-1)と平均値Ave.C(n-1)との差分ΔC1(n-1)、ΔC2(n-1)について付記したものである。即ち、
 ΔC1(n-1)=C1(n-1)-Ave.C(n-1) ・・・式(8)
 ΔC2(n-1)=Ave.C(n-1)-C2(n-1) ・・・式(9)
 ここで、流量が安定している場合、差分値は変化しないので、差分ΔC1と差分ΔC1(n-1)の差分ΔC11と差分ΔC2と差分ΔC2(n-1)の差分ΔC22とは、ノイズによって生じた変化量であり、ノイズで生じた変化量Xを用いて次式で求めることができる。
FIG. 6 shows the upstream propagation time C1 (n-1), the downstream propagation time C2 (n-1), and the average Ave. The differences ΔC1 (n-1) and ΔC2 (n-1) from C (n-1) are added. That is,
ΔC1 (n-1) = C1 (n-1) -Ave. C (n-1) ... Formula (8)
ΔC2 (n-1) = Ave. C (n-1) -C2 (n-1) formula (9)
Here, when the flow rate is stable, the difference value does not change, so the difference ΔC11 between the difference ΔC1 and the difference ΔC1 (n-1), the difference ΔC2 between the difference ΔC2, and the difference ΔC22 between the difference ΔC2 (n-1) It is the amount of change that has occurred, and can be obtained by the following equation using the amount of change X that is caused by noise.
 ΔC11=ΔC1-ΔC1(n-1)=-X/4 ・・・式(10)
 ΔC22=ΔC2-ΔC2(n-1)=+X・3/4 ・・・式(11)ここで、差分ΔC11:ΔC22=-1:+3の関係となることがわかる。
ΔC 11 = ΔC 1 −ΔC 1 (n−1) = − X / 4 (10)
ΔC22 = ΔC2−ΔC2 (n−1) = + X · 3/4 (11) Here, it can be seen that the difference ΔC11: ΔC22 = −1: +3.
 従って、計測異常判定部16は、流量有りの場合において、式(8)、式(9)により前回の差分ΔC1(n-1)とΔC2(n-1)を求めて保存しておき、今回の伝播時間測定時に式(10)、式(11)で差分ΔC11、ΔC22を演算して、このΔC11、ΔC22の比率が1:3であればノイズにより計測異常が生じていると判断することができる。 Therefore, when there is a flow rate, the measurement abnormality determination unit 16 obtains the previous differences ΔC1 (n-1) and ΔC2 (n-1) according to the equations (8) and (9) and stores them. The difference ΔC11 and ΔC22 are calculated by the equation (10) and the equation (11) at the time of measurement of the propagation time, and if the ratio of this ΔC11 and ΔC22 is 1: 3, it is judged that the measurement abnormality is caused by the noise. it can.
 そして、積算部17は、計測異常判定部16で計測異常が発生していると判断された場合には、今回、流量演算部12で計測された流量を積算せず、前回の流量値を積算するなど適切な処理を行うことで、誤った流量を積算することを防止することができる。 When the measurement abnormality determination unit 16 determines that the measurement abnormality is occurring, the integration unit 17 does not integrate the flow rate measured by the flow rate calculation unit 12 this time, and integrates the previous flow rate value. By performing appropriate processing such as, it is possible to prevent the integration of an erroneous flow rate.
 なお、差分ΔC1(n)、ΔC2(n)が共に小さい場合は、ノイズによる計測異常は発生していないと見なすことができ、逆に、差分ΔC1(n)、ΔC2(n)が共に大きい場合は、ノイズ以外の要因で大きな流量変化やガス種の切替による伝播時間の変動が発生していると判断できることから、|ΔC1(n)+ΔC2(n)|が所定範囲の場合に限って計測異常判定部16における計測異常の判定の実行するようにしてもよい。 In addition, when differences ΔC1 (n) and ΔC2 (n) are both small, it can be considered that measurement error due to noise does not occur, and conversely, when differences ΔC1 (n) and ΔC2 (n) are both large Since it can be judged that a large change in flow rate and a change in propagation time due to switching of gas types are occurring due to factors other than noise, measurement abnormality occurs only when | ΔC1 (n) + ΔC2 (n) | The determination of the measurement abnormality in the determination unit 16 may be executed.
 さらに、差分ΔC1または、差分ΔC2の値が極小の場合、|ΔC2|と|ΔC1|の比率計算(上記の|ΔC2|/|ΔC1|や、|ΔC1|/|ΔC2|の計算)をしたとき、計測誤差や、演算誤差の差から、偶然に式(7)を満たす可能性がある。そのため、比率計算を行う前に、例えば、次の式(12)で示す条件を満たしたときに、比率の計算を行うようにしてもよい。 Furthermore, when the difference ΔC1 or the value of the difference ΔC2 is a minimum, the ratio calculation of | ΔC2 | and | ΔC1 | (calculation of | ΔC2 | / | ΔC1 | or | ΔC1 | / | ΔC2 | above) is performed. Equation (7) may be met by chance from the difference of measurement error and calculation error. Therefore, before the ratio calculation, for example, when the condition shown in the following equation (12) is satisfied, the ratio may be calculated.
 m<|差分ΔC1+差分ΔC2| ・・・式(12)
 ここで、|差分ΔC1+差分ΔC2|は、ノイズがないときはゼロと演算されるものであり、mは0以上の値(例えば、10ns)に設定される。従って、式(12)を満たす場合にノイズによる計測異常の可能性が有るとして、計測異常判定部16による計測異常の判定を行うことで、誤判定を防止することができる。
m <| difference ΔC1 + difference ΔC2 | formula (12)
Here, | difference ΔC1 + difference ΔC2 | is calculated to be zero when there is no noise, and m is set to a value of 0 or more (for example, 10 ns). Therefore, it is possible to prevent an erroneous determination by determining the measurement abnormality by the measurement abnormality determining unit 16 on the assumption that there is a possibility of the measurement abnormality due to the noise when the expression (12) is satisfied.
 以上のように、本実施の形態によると、外乱等でノイズが混入し受信波形に大きな歪が生じてゼロクロス点がずれるような場合でも、精度よくノイズによる計測異常と判定することができる。そして、ノイズにより計測異常が生じていると判断される場合、積算部における流量積算を適切に行うことができる。 As described above, according to the present embodiment, even when noise is mixed due to disturbance or the like to cause a large distortion in the received waveform and the zero cross point shifts, it is possible to accurately determine that the measurement is abnormal due to the noise. Then, when it is determined that the measurement abnormality is caused by the noise, the flow rate integration in the integration unit can be appropriately performed.
 以上説明したように、第1の開示における流量計測装置は、被測定流体の流れる流路の上流に配置され超音波を送受信する第1超音波振動子と、流路の下流に配置され超音波を送受信する第2超音波振動子と、第1超音波振動子および第2超音波振動子を駆動する送信部と、を備える。また、第1の開示における流量計測装置は、第1超音波振動子および第2超音波振動子の送受信を切り換える切換部と、第1超音波振動子または第2超音波振動子の受信信号を所定の振幅まで増幅する増幅部と、増幅部の出力と基準電圧とを比較する基準比較部と、を備える。また、第1の開示における流量計測装置は、基準比較部と増幅部の出力とから超音波信号の到達時期を判定する判定部と、判定部で判定した超音波信号の到達時期から超音波信号の送受信の伝播時間を計時する計時部と、を備える。また、第1の開示における流量計測装置は、第1超音波振動子から第2超音波振動子への超音波の伝播時間を所定回数計測して平均した上流側伝播時間と、第2超音波振動子から第1超音波振動子への超音波の伝播時間を所定回数計測して平均した下流側伝播時間と、を求める伝播時間演算部を備える。また、第1の開示における流量計測装置は、上流側伝播時間または下流側伝播時間の計測異常を判定する計測異常判定部と、上流側伝播時間と下流側伝播時間の時間差から流量を演算する流量演算部と、を備える。さらに、第1の開示における流量計測装置は、伝播時間演算部が、所定時間間隔で上流側伝播時間と下流側伝播時間を演算し、計測異常判定部が、上流側伝播時間の今回値C1(n)と上流側伝播時間の前回値C1(n-1)と下流側伝播時間の今回値C2(n)と下流側伝播時間の前回値C2(n-1)に基づき計測異常を判定する。 As described above, the flow rate measuring device according to the first disclosure includes the first ultrasonic transducer disposed upstream of the flow path of the fluid to be measured and transmitting and receiving ultrasonic waves, and the ultrasonic wave disposed downstream of the flow path And a transmitter configured to drive the first ultrasonic transducer and the second ultrasonic transducer. The flow rate measuring device in the first disclosure includes a switching unit that switches transmission and reception of the first ultrasonic transducer and the second ultrasonic transducer, and a reception signal of the first ultrasonic transducer or the second ultrasonic transducer. An amplification unit that amplifies to a predetermined amplitude, and a reference comparison unit that compares the output of the amplification unit with a reference voltage. Further, the flow rate measuring apparatus in the first disclosure determines the arrival time of the ultrasound signal from the reference comparison unit and the output of the amplification unit, and the ultrasound signal from the arrival time of the ultrasound signal determined by the determination unit. And a clock unit for clocking the propagation time of transmission and reception of Further, in the flow rate measuring device according to the first disclosure, an upstream side propagation time obtained by measuring and averaging a propagation time of ultrasonic waves from the first ultrasonic transducer to the second ultrasonic transducer a predetermined number of times, and a second ultrasonic wave A propagation time calculation unit is provided for obtaining a downstream side propagation time obtained by measuring a propagation time of an ultrasonic wave from a transducer to a first ultrasonic transducer a predetermined number of times and averaging them. Further, the flow rate measuring device according to the first disclosure includes a measurement abnormality determination unit that determines measurement abnormality of the upstream side propagation time or the downstream side propagation time, and a flow rate that calculates the flow rate from the time difference between the upstream side propagation time and the downstream side propagation time And a calculation unit. Furthermore, in the flow rate measurement device in the first disclosure, the propagation time calculation unit calculates the upstream propagation time and the downstream propagation time at predetermined time intervals, and the measurement abnormality determination unit calculates the current value C1 of the upstream propagation time Measurement abnormality is determined based on n), the previous value C1 (n-1) of the upstream propagation time, the current value C2 (n) of the downstream propagation time, and the previous value C2 (n-1) of the downstream propagation time.
 第2の開示における流量計測装置は、特に、第1の開示において、計測異常判定部が、上流側伝播時間の今回値C1(n)と前回C1(n-1)の変化量ΔC1(n)と下流側伝播時間の今回値C2(n)と前回値C2(n-1)の変化量ΔC2(n)に基づき計測異常を判定してもよい。 The flow rate measuring apparatus according to the second disclosure, in particular, according to the first disclosure, the measurement abnormality determining unit determines that the change ΔC1 (n) between the current value C1 (n) of the upstream propagation time and the previous C1 (n-1). The measurement abnormality may be determined based on the current value C2 (n) of the downstream side propagation time and the change amount ΔC2 (n) of the previous value C2 (n-1).
 第3の開示における流量計測装置は、特に、第1の開示において、計測異常判定部が、上流側伝播時間の今回値C1(n)と下流側伝播時間の今回値C2(n)の平均値Ave.C(n)と上流側伝播時間の前回値C1(n-1)と下流側伝播時間の前回値C2(n-1)の平均値Ave.C(n-1)の平均値Ave.C(n-1)を算出してもよい。更に平均値Ave.C(n)と平均値Ave.C(n-1)の平均値Aveと上流側伝播時間の今回値C1(n)との差分ΔC1と平均値Aveと下流側伝播時間の今回値C2(n)との差分値ΔC2に基づき計測異常を判定してもよい。 Particularly in the first disclosure, in the flow measurement device in the third disclosure, the measurement abnormality determination unit is an average value of the current value C1 (n) of the upstream propagation time and the current value C2 (n) of the downstream propagation time. Ave. An average value Ave. of C (n), the previous value C1 (n-1) of the upstream side propagation time, and the previous value C2 (n-1) of the downstream side propagation time. Average value of C (n-1) Ave. C (n-1) may be calculated. Furthermore, the average value Ave. C (n) and the average Ave. Measurement based on the difference ΔC1 between the average value Ave of C (n-1) and the current value C1 (n) of the upstream propagation time, and the difference value ΔC2 between the average Ave and the current value C2 (n) of the downstream propagation time An abnormality may be determined.
 第4の開示における流量計測装置は、特に、第3の開示において、計測異常判定部が、差分値ΔC1と差分値ΔC2の比率に基づき計測異常を判定してもよい。 Especially in the third disclosure, the measurement abnormality determination unit in the fourth disclosure may determine the measurement abnormality based on the ratio of the difference value ΔC1 to the difference value ΔC2.
 第5の開示における流量計測装置は、特に、第1の開示~第4の開示のいずれか1つにおいて、計測異常判定部が、流量演算部で求めた流量が所定流量以下の場合に計測異常の判定を行うこととしてもよい。 The flow rate measuring apparatus according to the fifth aspect of the present invention is the flow rate measuring apparatus according to any one of the first to fourth aspects, wherein the measurement fault determining unit determines that the flow rate measured by the flow rate computing unit is less than a predetermined flow rate. It is also possible to make the determination of
 第6の開示における流量計測装置は、特に、第1の開示~第5の開示いずれか1つにおいて、流量演算部で求めた流量を積算する積算部を備え、この積算部が、計測異常判定部で計測異常と判定した場合、積算を行わないこととしてもよい。 The flow rate measuring apparatus according to the sixth aspect of the present invention particularly includes, in any one of the first to fifth aspects, an integrating section that integrates the flow rate obtained by the flow rate calculating section, and the integrating section determines measurement abnormality. If it is determined by the unit that measurement is abnormal, integration may not be performed.
 以上のように、本発明にかかる流量計測装置は、乱等でノイズが混入し受信波形に大きな歪が生じてゼロクロス点がずれるような場合でも、精度よくノイズによる計測異常と判定することができるので、様々な気体の計測器や家庭用から業務用に至る大型のガスメータ等の幅広い用途に適用できる。 As described above, the flow rate measuring apparatus according to the present invention can accurately determine that the measurement is abnormal due to noise even when noise is mixed by disturbance or the like to cause large distortion in the received waveform and the zero cross point is shifted. Therefore, it can be applied to a wide range of applications such as various gas measuring instruments and large gas meters ranging from household use to business use.
 1 流路
 2 第1超音波振動子
 3 第2超音波振動子
 4 切換部
 5 送信部
 6 受信部
 7 増幅部
 8 基準比較部
 9 基準電圧設定部
 10 判定部
 11 計時部
 12 流量演算部
 13 制御部
 14 流量計測装置
 15 伝播時間演算部
 16 計測異常判定部
REFERENCE SIGNS LIST 1 flow path 2 first ultrasonic transducer 3 second ultrasonic transducer 4 switching unit 5 transmitting unit 6 receiving unit 7 amplifying unit 8 reference comparing unit 9 reference voltage setting unit 10 determination unit 11 timing unit 12 flow rate calculating unit 13 control Unit 14 Flow measurement device 15 Propagation time calculation unit 16 Measurement abnormality judgment unit

Claims (7)

  1. 被測定流体の流れる流路の上流に配置され超音波を送受信する第1超音波振動子と、
    前記流路の下流に配置され超音波を送受信する第2超音波振動子と、
    前記第1超音波振動子および前記第2超音波振動子を駆動する送信部と、
    前記第1超音波振動子および前記第2超音波振動子の送受信を切り換える切換部と、
    前記第1超音波振動子または前記第2超音波振動子の受信信号を所定の振幅まで増幅する増幅部と、
    前記増幅部の出力と基準電圧とを比較する基準比較部と、
    前記基準比較部と前記増幅部の出力とから超音波信号の到達時期を判定する判定部と、
    前記判定部で判定した超音波信号の到達時期から前記超音波信号の送受信の伝播時間を計時する計時部と、
    前記第1超音波振動子から前記第2超音波振動子への超音波の伝播時間を所定回数計測して平均した上流側伝播時間と、前記第2超音波振動子から前記第1超音波振動子への超音波の伝播時間を所定回数計測して平均した下流側伝播時間と、を求める伝播時間演算部と、
    前記上流側伝播時間または前記下流側伝播時間の計測異常を判定する計測異常判定部と、
    前記上流側伝播時間と前記下流側伝播時間の時間差から流量を演算する流量演算部と、を備え、
    前記伝播時間演算部は、所定時間間隔で前記上流側伝播時間と前記下流側伝播時間を演算し、
    前記計測異常判定部は、前記上流側伝播時間の今回値C1(n)と前記上流側伝播時間の前回値C1(n-1)と前記下流側伝播時間の今回値C2(n)と前記下流側伝播時間の前回値C2(n-1)に基づき計測異常を判定する流量計測装置。
    A first ultrasonic transducer disposed upstream of a flow path through which the fluid to be measured flows to transmit and receive ultrasonic waves;
    A second ultrasonic transducer disposed downstream of the flow path for transmitting and receiving ultrasonic waves;
    A transmitter configured to drive the first ultrasonic transducer and the second ultrasonic transducer;
    A switching unit that switches transmission and reception of the first ultrasonic transducer and the second ultrasonic transducer;
    An amplification unit configured to amplify the reception signal of the first ultrasonic transducer or the second ultrasonic transducer to a predetermined amplitude;
    A reference comparison unit that compares the output of the amplification unit with a reference voltage;
    A determination unit that determines an arrival time of an ultrasonic signal from the reference comparison unit and the output of the amplification unit;
    A timing unit which measures the propagation time of transmission / reception of the ultrasonic signal from the arrival time of the ultrasonic signal determined by the determination unit;
    An upstream side propagation time obtained by averaging and measuring an ultrasonic wave propagation time from the first ultrasonic transducer to the second ultrasonic transducer a predetermined number of times, and the first ultrasonic vibration from the second ultrasonic transducer A propagation time calculation unit for determining the downstream propagation time obtained by measuring the propagation times of ultrasonic waves to the child a predetermined number of times and averaging them;
    A measurement abnormality determination unit that determines measurement abnormality of the upstream side propagation time or the downstream side propagation time;
    A flow rate calculating unit that calculates a flow rate from a time difference between the upstream side propagation time and the downstream side propagation time,
    The propagation time calculation unit calculates the upstream side propagation time and the downstream side propagation time at predetermined time intervals,
    The measurement abnormality determination unit includes a current value C1 (n) of the upstream side propagation time, a previous value C1 (n-1) of the upstream side propagation time, and a current value C2 (n) of the downstream side propagation time A flow rate measuring device that determines measurement abnormality based on the previous value C2 (n-1) of side propagation time.
  2. 前記計測異常判定部は、前記上流側伝播時間の前記今回値C1(n)と前記前回値C1(n-1)の変化量ΔC1(n)と前記下流側伝播時間の前記今回値C2(n)と前記前回値C2(n-1)の変化量ΔC2(n)に基づき計測異常を判定する請求項1に記載の流量計測装置。 The measurement abnormality determination unit determines the current value C1 (n) of the upstream side propagation time, the variation ΔC1 (n) of the previous value C1 (n-1), and the current value C2 (n) of the downstream side propagation time. The flow rate measuring apparatus according to claim 1, wherein the measurement abnormality is determined based on the change amount ΔC2 (n) of the previous value C2 (n-1) and the previous value C2 (n-1).
  3. 前記計測異常判定部は、前記上流側伝播時間の前記今回値C1(n)と前記下流側伝播時間の前記今回値C2(n)の平均値Ave.C(n)と前記上流側伝播時間の前記前回値C1(n-1)と前記下流側伝播時間の前記前回値C2(n-1)の平均値Ave.C(n-1)を算出し、更に前記平均値Ave.C(n)と前記平均値Ave.C(n-1)の平均値Aveと前記上流側伝播時間の前記今回値C1(n)との差分ΔC1と前記平均値Aveと前記下流側伝播時間の前記今回値C2(n)との差分値ΔC2に基づき計測異常を判定することを特徴とする請求項1記載の流量計測装置。 The measurement abnormality determination unit determines an average value Ave. of the current value C1 (n) of the upstream side propagation time and the current value C2 (n) of the downstream side propagation time. C (n), the previous value C1 (n-1) of the upstream side propagation time, and the average value Ave. of the previous value C2 (n-1) of the downstream side propagation time. C (n-1) is calculated, and the average value Ave. C (n) and the average Ave. The difference ΔC1 between the average value Ave of C (n-1) and the current value C1 (n) of the upstream side propagation time, the difference between the average value Ave and the current value C2 (n) of the downstream side propagation time The flow rate measuring apparatus according to claim 1, wherein the measurement abnormality is determined based on the value ΔC2.
  4. 前記計測異常判定部は、前記差分値ΔC1と前記差分値ΔC2の比率に基づき計測異常を判定することを特徴とする請求項3記載の流量計測装置。 The flow measurement device according to claim 3, wherein the measurement abnormality determination unit determines measurement abnormality based on a ratio of the difference value ΔC1 and the difference value ΔC2.
  5. 前記計測異常判定部は、前記流量演算部で求めた流量が所定流量以下の場合に計測異常の判定を行うことを特徴とする請求項1~4のいずれか1項に記載の流量計測装置。 The flow rate measuring apparatus according to any one of claims 1 to 4, wherein the measurement abnormality determining unit determines the measurement abnormality when the flow rate obtained by the flow rate calculating unit is equal to or less than a predetermined flow rate.
  6. 前記流量演算部で求めた流量を積算する積算部を備え、前記積算部は、前記計測異常判定部で計測異常と判定した場合、積算を行わないことを特徴とする請求項1~4のいずれか1項に記載の流量計測装置。 The integration part which integrates the flow volume calculated | required by the said flow volume calculating part is provided, The said integration part does not integrate, when it determines with measurement abnormality by the said measurement abnormality determination part, The integration is not characterized by any one The flow rate measuring device according to claim 1 or 2.
  7. 前記流量演算部で求めた流量を積算する積算部を備え、該積算部は、前記計測異常判定部で計測異常と判定した場合、積算を行わないことを特徴とする請求項5に記載の流量計測装置。 The flow rate according to claim 5, further comprising: an integration unit that integrates the flow rate determined by the flow rate calculation unit, wherein the integration unit does not perform integration when the measurement abnormality determination unit determines that the measurement abnormality occurs. Measuring device.
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Citations (4)

* Cited by examiner, † Cited by third party
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JPS5728286A (en) * 1980-07-28 1982-02-15 Yokogawa Hokushin Electric Corp Ultrasonic measuring device
JPH073346B2 (en) * 1986-02-05 1995-01-18 株式会社トキメック Ultrasonic flowmeter measurement value processing method
JP3622613B2 (en) * 1999-12-27 2005-02-23 松下電器産業株式会社 Ultrasonic flow meter
JP5141613B2 (en) * 2009-03-25 2013-02-13 パナソニック株式会社 Ultrasonic flow meter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5728286A (en) * 1980-07-28 1982-02-15 Yokogawa Hokushin Electric Corp Ultrasonic measuring device
JPH073346B2 (en) * 1986-02-05 1995-01-18 株式会社トキメック Ultrasonic flowmeter measurement value processing method
JP3622613B2 (en) * 1999-12-27 2005-02-23 松下電器産業株式会社 Ultrasonic flow meter
JP5141613B2 (en) * 2009-03-25 2013-02-13 パナソニック株式会社 Ultrasonic flow meter

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