JP3473341B2 - Ultrasonic flow meter - Google Patents
Ultrasonic flow meterInfo
- Publication number
- JP3473341B2 JP3473341B2 JP21151197A JP21151197A JP3473341B2 JP 3473341 B2 JP3473341 B2 JP 3473341B2 JP 21151197 A JP21151197 A JP 21151197A JP 21151197 A JP21151197 A JP 21151197A JP 3473341 B2 JP3473341 B2 JP 3473341B2
- Authority
- JP
- Japan
- Prior art keywords
- ultrasonic
- circuit
- time
- ultrasonic transducer
- reception
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Measuring Volume Flow (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は超音波の伝搬によっ
て流量を測定する超音波流量計に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flowmeter for measuring a flow rate by propagating ultrasonic waves.
【０００２】[0002]
【従来の技術】従来この種の超音波流量計は、特開平９
−１３３５６０号公報に示すものが一般的であった。こ
の構成は、図１３に示されているように、流体の中に配
置し超音波を送受信する１対の超音波振動子（超音波振
動子３、超音波振動子４）と、送信側の超音波振動子を
駆動する送信回路１と、被測定流体を伝搬した超音波を
受信する受信側の超音波振動子の出力信号から受信判定
し送信回路１に出力する受信回路２と、超音波振動子
３、４と送信回路１と受信回路２の接続を送受切り替え
ることによって送受の方向を切り替える切り替え器５
と、切り替え器５を制御し送受の方向を交互に切り替え
測定開始信号を送信回路１に出力する制御部６と、超音
波の送信から受信そして帰還までの繰り返しの回数を計
測するカウンタ７と、１回目の超音波の送信開始から繰
り返しの回数が所定回数に達するまでの時間を計測する
第１のタイマ８と、第１のタイマ８の値から流量を求め
る演算部９と、超音波の送信から伝搬時間より短い時間
ＯＮ信号を出力する第２のタイマ１０と、第２のタイマ
１０のＯＮ出力によって受信回路２の電源をＯＦＦする
電力制御部１１とを備えていた。2. Description of the Related Art A conventional ultrasonic flowmeter of this type is disclosed in Japanese Patent Laid-Open No.
The one shown in Japanese Patent Laid-Open No. 133560 has been general. As shown in FIG. 13, this configuration has a pair of ultrasonic transducers (ultrasonic transducers 3 and 4) arranged in a fluid for transmitting and receiving ultrasonic waves, and a pair of ultrasonic transducers on the transmitting side. A transmitting circuit 1 for driving the ultrasonic transducer, a receiving circuit 2 for judging reception from an output signal of the ultrasonic transducer on the receiving side for receiving the ultrasonic wave propagated in the fluid to be measured, and outputting the same to the transmitting circuit 1, A switcher 5 that switches the transmission / reception direction by switching the connection between the oscillators 3 and 4, the transmission circuit 1 and the reception circuit 2 between transmission and reception.
And a control unit 6 for controlling the switcher 5 to alternately switch the transmission / reception directions and outputting a measurement start signal to the transmission circuit 1, and a counter 7 for measuring the number of repetitions from transmission of ultrasonic waves to reception and return of ultrasonic waves. A first timer 8 that measures the time from the start of the first transmission of ultrasonic waves until the number of repetitions reaches a predetermined number, a calculation unit 9 that calculates the flow rate from the value of the first timer 8, and the transmission of ultrasonic waves The second timer 10 that outputs an ON signal for a time shorter than the propagation time and the power control unit 11 that turns off the power supply of the receiving circuit 2 by the ON output of the second timer 10 are provided.
【０００３】動作を説明する。まず制御部６が切り替え
器５を制御し超音波を伝搬させる方向を決める。ここで
は超音波は超音波振動子３から超音波振動子４に伝搬さ
せる。その後制御部６は測定開始信号を送信回路１に出
力する。測定開始信号を受けた送信回路１は超音波振動
子３を駆動し、超音波振動子３は超音波を送信する。超
音波振動子４は被測定流体を伝搬してきた超音波を受信
し受信信号を受信回路２に出力する。受信回路２は受信
判定を行い超音波の受信を確認した場合送信回路１に出
力を行う。受信回路２の出力を受けた送信回路１は再度
超音波振動子３を駆動する。カウンタ７はこの超音波の
送信から受信の回数を数え、この回数がカウンタ７の設
定値（Ｎ回）に達した場合第１のタイマ８を停止させ
る。第１のタイマ８は測定開始からの時間を計測してお
り、この時の第１のタイマ８の値ｔ１は超音波の伝搬時
間のＮ倍となる。次に制御部６は超音波の伝搬させる方
向を超音波振動子４から超音波振動子３に切り替える。
そして前回の測定と同様な動作をさせｔ２を測定する。
この値をもとに演算部９は次の計算によって流量を求め
る。The operation will be described. First, the control unit 6 controls the switch 5 to determine the direction in which ultrasonic waves are propagated. Here, the ultrasonic wave is propagated from the ultrasonic vibrator 3 to the ultrasonic vibrator 4. After that, the control unit 6 outputs a measurement start signal to the transmission circuit 1. The transmission circuit 1 that has received the measurement start signal drives the ultrasonic transducer 3, and the ultrasonic transducer 3 transmits ultrasonic waves. The ultrasonic transducer 4 receives the ultrasonic wave propagating through the fluid to be measured and outputs a reception signal to the reception circuit 2. The reception circuit 2 makes a reception determination and outputs to the transmission circuit 1 when the reception of ultrasonic waves is confirmed. The transmission circuit 1 receiving the output of the reception circuit 2 drives the ultrasonic transducer 3 again. The counter 7 counts the number of times the ultrasonic waves are transmitted and received, and when the number of times reaches the set value (N times) of the counter 7, the first timer 8 is stopped. The first timer 8 measures the time from the start of measurement, and the value t1 of the first timer 8 at this time is N times the propagation time of ultrasonic waves. Next, the control unit 6 switches the ultrasonic wave propagation direction from the ultrasonic vibrator 4 to the ultrasonic vibrator 3.
Then, the same operation as the previous measurement is performed to measure t2.
Based on this value, the calculation unit 9 obtains the flow rate by the following calculation.
【０００４】超音波の伝搬距離をＬ、被測定流体の流れ
る断面積をＳ、被測定流体の静止時の音速をＣ、被測定
流体の流速をＶ、上流から下流方向への伝搬時間をｔ
１、カウンタ７の設定値とした場合の流量Ｑを求める計
算式を（式１）に示す。The propagation distance of the ultrasonic wave is L, the cross-sectional area of the fluid to be measured is S, the sonic velocity of the fluid to be measured at rest is C, the flow velocity of the fluid to be measured is V, and the propagation time from upstream to downstream is t.
1, the equation for calculating the flow rate Q when the counter 7 is set is shown in (Equation 1).
【０００５】
Ｑ＝ＳＬ［（１／ｔ１／Ｎ）−（１／ｔ２／Ｎ）］・・・・・（式１）
電力制御部１１は１回目の超音波の送信、または超音波
を受信回路２による受信判定と同時にＯＦＦ信号を出力
し受信回路の電源をＯＦＦする。第２のタイマ１０は受
信回路の電源ＯＦＦと同時に動作し、超音波の送信から
超音波の伝搬時間より短い時間の後に電力制御部１１に
ＯＮ信号を出力する。その信号によって電力制御部１１
は受信回路２の電源をＯＮする。この動作によって電力
消費を少なくしていた。Q = SL [(1 / t1 / N)-(1 / t2 / N)] (Equation 1) The power control unit 11 transmits the first ultrasonic wave or receives the ultrasonic wave. Simultaneously with the reception determination by the circuit 2, an OFF signal is output to turn off the power of the receiving circuit. The second timer 10 operates at the same time as the power of the receiving circuit is turned off, and outputs an ON signal to the power control unit 11 after a time shorter than the propagation time of ultrasonic waves from the transmission of ultrasonic waves. The power control unit 11 according to the signal
Turns on the power of the receiving circuit 2. This operation reduced power consumption.
【０００６】またこの構成では、超音波が終端へ到着す
ると同時に再度同経路に超音波を伝搬させるという動作
を行い、伝搬時間の測定分解能を上げていた。Further, in this configuration, the ultrasonic wave reaches the terminal end, and at the same time, the ultrasonic wave is propagated to the same path again, thereby increasing the measurement resolution of the propagation time.
【０００７】また、図示していないが受信回路２と送信
回路１の間に、受信回路２の出力を受け所定の遅延時間
経過後に送信回路１へ出力する帰還回路を設け、超音波
振動子間を反射した後受信側の超音波振動子で受信され
る反射波と、送信側の超音波振動子から送信され直接受
信側の超音波振動子で受信する直接波との受信タイミン
グを外し測定誤差を小さくしているものもあった。Although not shown, a feedback circuit for receiving the output of the receiving circuit 2 and outputting it to the transmitting circuit 1 after a lapse of a predetermined delay time is provided between the receiving circuit 2 and the transmitting circuit 1. Measurement error by removing the reception timing of the reflected wave that is received by the ultrasonic transducer on the receiving side after being reflected by the ultrasonic transducer on the receiving side and the direct wave that is transmitted from the ultrasonic transducer on the transmitting side and directly received by the ultrasonic transducer on the receiving side. There were some that made the value smaller.
【０００８】また超音振動子の送受信感度は流体、温
度、経年変化、設置状態等によって大きく変動し、この
変動の吸収を送信出力変更、受信回路の定数変更などに
よって行っているものもあった。Further, the transmission / reception sensitivity of the ultrasonic transducer fluctuates greatly depending on the fluid, temperature, aging, installation condition, etc., and some of the fluctuations are absorbed by changing the transmission output or the constant of the receiving circuit. .
【０００９】[0009]
【発明が解決しようとする課題】しかしながら、従来の
超音波流量計では受信回路の電源をＯＮ、ＯＦＦする時
に受信回路の動作が不安定になり誤動作を起こしやすい
ので、低電力での測定と動作の安定性との両方を実現す
ることが課題となっていた。However, in the conventional ultrasonic flowmeter, when the power of the receiving circuit is turned on and off, the operation of the receiving circuit becomes unstable and a malfunction easily occurs, so that measurement and operation with low power are performed. It was a challenge to achieve both stability of.
【００１０】また帰還回路の遅延時間が固定なので、伝
搬時間によっては反射波と直接波との受信タイミングが
重なり測定精度が落るので測定条件が限定されていた。
そのため測定条件の拡大化という課題を有していた。Further, since the delay time of the feedback circuit is fixed, the reception timing of the reflected wave and the direct wave may overlap depending on the propagation time and the measurement accuracy may be deteriorated, so that the measurement conditions are limited.
Therefore, there is a problem that the measurement conditions are expanded.
【００１１】[0011]
【課題を解決するための手段】本願発明の超音波流量計
においては、超音波を送信する第１の超音波振動子と、
前記第１の超音波振動子を駆動する送信回路と、被測定
流体を伝搬した超音波を受信する第２の超音波振動子
と、前記第２の超音波振動子の出力信号から受信判定す
る受信回路と、前記受信回路の出力を受け所定の遅延時
間経過後に前記送信回路へ出力する帰還回路と、前記超
音波の送信から受信そして帰還までの繰り返しの回数を
計測するカウンタと、前記繰り返しの回数が所定回数に
達するまでの時間を計測するタイマと、前記タイマの値
から流量を求める演算部と、前記超音波が前記第１の超
音波振動子から前記第２の超音波振動子に達するまでの
伝搬時間の長さに応じて前記繰り返しの回数を低減し、
伝搬時間と繰り返し回数の積がほぼ一定となるようにす
る繰り返し制御部を備えたものである。In the ultrasonic flowmeter of the present invention, a first ultrasonic transducer for transmitting ultrasonic waves,
A transmission circuit that drives the first ultrasonic transducer, a second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, and reception determination from the output signal of the second ultrasonic transducer A receiving circuit, a feedback circuit that receives the output of the receiving circuit and outputs it to the transmitting circuit after a predetermined delay time has passed, a counter that measures the number of repetitions from the transmission of the ultrasonic waves to the reception and the return of the ultrasonic waves, A timer that measures the time until the number of times reaches a predetermined number, an arithmetic unit that obtains a flow rate from the value of the timer, and the ultrasonic wave reaches the second ultrasonic vibrator from the first ultrasonic vibrator. Reduce the number of repetitions according to the length of the propagation time to
It is provided with a repetition control unit that keeps the product of the propagation time and the number of repetitions substantially constant.
【００１２】この発明によれば、くり返し制御部が、超
音波が被測定流体を伝搬する時間が長くなるに応じてく
り返し回数を低減するので、伝搬時間が長くなると繰り
返し回数が少なくなる。つまり、伝搬時間が長くなって
も測定時間が大幅に伸びることがなく、従来のものと比
べて低電力化できる。According to the present invention, repeated control unit, since ultrasonic waves to reduce the repetition number according to the time to propagate the fluid to be measured is long, the number of repetitions and the propagation time may turn longer decreases. That is, even if the propagation time becomes long, the measurement time does not significantly increase, and the power consumption can be reduced as compared with the conventional one.
【００１３】[0013]
【発明の実施の形態】（１）超音波を送信する第１の超
音波振動子と、前記第１の超音波振動子を駆動する送信
回路と、被測定流体を伝搬した超音波を受信する第２の
超音波振動子と、前記第２の超音波振動子の出力信号か
ら受信判定する受信回路と、前記受信回路の出力を受け
所定の遅延時間経過後に前記送信回路へ出力する帰還回
路と、前記超音波の送信から受信そして帰還までの繰り
返しの回数を計測するカウンタと、前記繰り返しの回数
が所定回数に達するまでの時間を計測するタイマと、前
記タイマの値から流量を求める演算部と、前記超音波が
前記第１の超音波振動子から前記第２の超音波振動子に
達するまでの伝搬時間が長くなるに応じて前記繰り返し
の回数を増減し、伝搬時間と繰り返し回数の積がほぼ一
定となるようにする繰り返し制御部を備え、伝搬時間が
長くなるに対応してくり返し回数をへらす。このため精
度を落とさずに繰り返し回数が少なくなり、低電力化で
きる。BEST MODE FOR CARRYING OUT THE INVENTION (1) A first ultrasonic oscillator for transmitting ultrasonic waves, a transmission circuit for driving the first ultrasonic oscillator, and an ultrasonic wave propagating in a fluid to be measured. A second ultrasonic transducer, a receiving circuit for receiving and judging from an output signal of the second ultrasonic transducer, and a feedback circuit for receiving the output of the receiving circuit and outputting it to the transmitting circuit after a lapse of a predetermined delay time. A counter that measures the number of repetitions of the ultrasonic wave from transmission to reception and return, a timer that measures the time until the number of repetitions reaches a predetermined number, and a calculation unit that calculates the flow rate from the value of the timer. , The number of repetitions is increased or decreased as the propagation time of the ultrasonic waves from the first ultrasonic transducer to the second ultrasonic transducer becomes longer, and the product of the propagation time and the number of repetitions is increased or decreased. To be almost constant Comprising a repetitive controller, Reducing the repetition number of times corresponding to the propagation time is long. For this reason, the number of repetitions can be reduced without lowering the accuracy, and the power consumption can be reduced.
【００１４】（２）超音波を送信する第１の超音波振動
子と、前記第１の超音波振動子を駆動する送信回路と、
被測定流体を伝搬した超音波を受信する第２の超音波振
動子と、前記第２の超音波振動子の出力信号から受信判
定する受信回路と、前記受信回路の出力を受け所定の遅
延時間経過後に前記送信回路へ出力する帰還回路と、前
記超音波の送信から受信そして帰還までの繰り返しの回
数を計測するカウンタと、前記繰り返しの回数が所定回
数に達するまでの時間を計測するタイマと、前記タイマ
の値から流量を求める演算部と、前記超音波が前記弟１
の超音波振動子から前記第２の超音波振動子に達するま
での伝搬時間に応じて前記遅延時間を制御し、遅延時間
を伝搬時間の整数倍に一致しない値とする遅延制御部を
備え、伝搬時間によって遅延時間を変化させる。このた
め大きく伝搬時間が変化した場合であっても、超音振動
子間を反射した後第２の超音波振動子で受信される反射
波と直接第１の超音波振動子から送信された超音波を第
２の超音波振動子で受信するタイミングとを外すことが
でき、伝搬時間の短い流体から長い流体まで正確な測定
を行うことができる。また遅延時間を反射波と直接波が
重ならない最短の時間に設定可能であるため、測定時間
が短くなり低電力化できる。(2) A first ultrasonic oscillator for transmitting ultrasonic waves, and a transmission circuit for driving the first ultrasonic oscillator,
A second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, a receiving circuit that determines whether or not the output signal of the second ultrasonic transducer is received, and a predetermined delay time that receives the output of the receiving circuit. A feedback circuit that outputs to the transmission circuit after a lapse of time, a counter that measures the number of repetitions from transmission of the ultrasonic waves to reception and feedback, and a timer that measures the time until the number of repetitions reaches a predetermined number, The calculation unit that obtains the flow rate from the value of the timer and the ultrasonic wave
A delay control unit that controls the delay time in accordance with a propagation time from the ultrasonic transducer to reach the second ultrasonic transducer, and sets the delay time to a value that does not match an integral multiple of the propagation time, The delay time is changed according to the propagation time. Therefore, even when the propagation time changes significantly, the reflected wave received by the second ultrasonic transducer after being reflected between the ultrasonic transducers and the ultrasonic wave directly transmitted from the first ultrasonic transducer. The timing with which the second ultrasonic transducer receives the sound wave can be omitted, and accurate measurement can be performed from a fluid with a short propagation time to a fluid with a long propagation time. Further, since the delay time can be set to the shortest time that the reflected wave and the direct wave do not overlap with each other, the measurement time can be shortened and the power consumption can be reduced.
【００１５】（３）超音波を送信する第１の超音波振動
子と、前記第１の超音波振動子を駆動する送信回路と、
被測定流体を伝搬した超音波を受信する第２の超音波振
動子と、前記第２の超音波振動子の出力信号から受信判
定する受信回路と、前記受信回路の出力を受け所定の遅
延時間経過後に前記送信回路へ出力する帰還回路と、前
記超音波の送信から受信そして帰還までの繰り返しの回
数を計測するカウンタと、前記繰り返しの回数が所定回
数に達する時間を計測するタイマと、前記タイマの値か
ら流量を求める演算部と、超音波の伝搬時間より所定時
間短い時間と前記遅延時間とを含む間前記受信回路の電
力消費を減少するよう制御する電力制御部とを備え、遅
延時間と、伝搬時間より所定時間短い間との両方の時間
受信回路の電力を低減させる。このため低電力化でき
る。(3) A first ultrasonic oscillator for transmitting ultrasonic waves, and a transmission circuit for driving the first ultrasonic oscillator,
A second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, a receiving circuit that determines whether or not the output signal of the second ultrasonic transducer is received, and a predetermined delay time that receives the output of the receiving circuit. A feedback circuit that outputs to the transmission circuit after a lapse of time, a counter that measures the number of repetitions of the ultrasonic wave from transmission to reception and return, a timer that measures the time when the number of repetitions reaches a predetermined number, and the timer And a power control unit that controls to reduce the power consumption of the receiving circuit while including a delay time and a time shorter than a propagation time of ultrasonic waves by a predetermined time, and a delay time , The power of the receiving circuit is reduced both during a predetermined time shorter than the propagation time and during a predetermined time. Therefore, the power consumption can be reduced.
【００１６】（４）超音波を送信する第１の超音波振動
子と、前記第１の超音波振動子を駆動する送信回路と、
被測定流体を伝搬した超音波を受信する第２の超音波振
動子と、前記第２の超音波振動子の出力信号から受信判
定する受信回路と、前記受信回路の中にあり前記第２の
超音波振動子の出力信号を直接あるいは信号処理の後に
受け超音波の受信タイミングを検知するタイミング検知
回路と、前記タイミング検知回路の出力を受け所定の遅
延時間経過後に前記送信回路へ出力する帰還回路と、前
記超音波の送信から受信そして帰還までの繰り返しの回
数を計測するカウンタと、前記繰り返しの回数が所定回
数に達する時間を計測するタイマと、前記タイマの値か
ら流量を求める演算部と、前記タイミング検知回路入力
信号のピークを検知するピーク検知手段と、前記ピーク
検知手段の出力を受け前記タイミング検知回路入力信号
のピークを一定に保つ受信信号安定手段と、前記受信回
路の電力を低減する電力制御部とを備え、前記ピーク検
知手段がピークレベルを検知した後から前記第２の超音
波振動子に超音波が受信される一定時間前まで前記電力
制御手段が前記受信回路の電力を低減する。このためピ
ーク検知手段が超音波信号のピークレベルを正確に検知
し、受信信号のピークを一定の値とすることができる。
さらに受信波のピークを一定にたもつ動作を行った状態
で長い時間受信回路の電力を低減できるので、省電力化
できる。(4) A first ultrasonic oscillator for transmitting ultrasonic waves, and a transmission circuit for driving the first ultrasonic oscillator,
A second ultrasonic transducer for receiving the ultrasonic waves propagated through the fluid to be measured, a receiving circuit for determining reception from the output signal of the second ultrasonic transducer, and the second ultrasonic transducer in the receiving circuit. A timing detection circuit that receives the output signal of the ultrasonic transducer directly or after the signal processing and detects the reception timing of the ultrasonic wave, and a feedback circuit that receives the output of the timing detection circuit and outputs it to the transmission circuit after a lapse of a predetermined delay time. A counter for measuring the number of repetitions from the transmission of ultrasonic waves to reception and return, a timer for measuring the time for which the number of repetitions reaches a predetermined number, and an arithmetic unit for obtaining a flow rate from the value of the timer, A peak detecting means for detecting a peak of the timing detecting circuit input signal; and a constant peak of the timing detecting circuit input signal for receiving an output of the peak detecting means. One receiving signal stabilizing means and a power control section for reducing the power of the receiving circuit, and a constant ultrasonic wave is received by the second ultrasonic transducer after the peak detecting means detects a peak level. Until time before, the power control means reduces the power of the receiving circuit. Therefore, the peak detecting means can accurately detect the peak level of the ultrasonic signal and make the peak of the received signal a constant value.
Further, the power of the receiving circuit can be reduced for a long time in the state where the operation with the peak of the received wave is performed, so that the power can be saved.
【００１７】（５）超音波を送信する第１の超音波振動
子と、前記第１の超音波振動子を駆動する送信回路と、
被測定流体を伝搬した超音波を受信する第２の超音波振
動子と、前記第２の超音波振動子の出力信号から受信判
定する受信回路と、前記受信回路の出力を受け所定の遅
延時間経過後に前記送信回路へ出力する帰還回路と、前
記超音波の送信から受信そして帰還までの回数を計測す
るカウンタと、前記繰り返しの回数が所定回数に達する
時間を計測するタイマと、前記タイマの値から流量を求
める演算部と、少なくとも超音波の伝搬開始から伝搬時
間より所定の時間短い間前記受信回路の電力を抑制する
電力制御部とを備え、測定初期は前記電力を抑制を解除
するタイミングを早くする。このため受信回路の電源投
入時あるいは電力抑制動作から定常動作への変更時に、
受信回路の動作が安定となるまでの時間が長い測定初期
は早期に電力抑制を解除し、受信回路の動作が安定とな
るまでの時間が短い測定後期には電力抑制の時間を長く
する。この制御によって、必要以上の時間受信回路を電
力の大きい定常動作させる必要がないので、省電力化で
きる。(5) A first ultrasonic transducer for transmitting ultrasonic waves, and a transmission circuit for driving the first ultrasonic transducer,
A second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, a receiving circuit that determines whether or not the output signal of the second ultrasonic transducer is received, and a predetermined delay time that receives the output of the receiving circuit. A feedback circuit that outputs to the transmission circuit after a lapse of time, a counter that measures the number of times from transmission to reception and return of the ultrasonic waves, a timer that measures the time when the number of repetitions reaches a predetermined number, and the value of the timer And a power control unit that suppresses the power of the receiving circuit at least for a predetermined time shorter than the propagation time from the start of propagation of ultrasonic waves, and at the initial stage of measurement, set the timing for canceling the power suppression. Make it faster Therefore, when the power of the receiving circuit is turned on or when the power saving operation is changed to the steady operation,
It takes a long time for the operation of the receiving circuit to be stable. The power suppression is canceled early in the initial measurement, and the time for the power suppression is extended in the latter period of the measurement, where the operation time of the receiving circuit is short. By this control, it is not necessary to operate the receiving circuit with a large amount of power for a longer period of time than necessary, so power can be saved.
【００１８】（６）超音波を送信する第１の超音波振動
子と、前記第１の超音波振動子を駆動する送信回路と、
被測定流体を伝搬した超音波を受信する第２の超音波振
動子と、前記第２の超音波振動子の出力信号から受信判
定する受信回路と、前記受信回路の出力を受け所定の遅
延時間経過後に前記送信回路へ出力する帰還回路と、前
記超音波の送信から受信そして帰還までの繰り返しの回
数を測定するカウンタと、前記超音波受信回路の電力を
制御する電力制御部と、前記繰り返し回数が２回目以降
の設定した値から終了設定した値までの時間を計測する
タイマと、前記タイマの値から流量を求める演算部とを
備え、安定した状態からタイマ計測を開始する。このた
め測定初期に発生しやすい電源投入あるいは低電力動作
から定常動作への変化によって起こる測定誤差を排除す
るので、安定な測定ができる。(6) A first ultrasonic transducer for transmitting ultrasonic waves, and a transmission circuit for driving the first ultrasonic transducer,
A second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, a receiving circuit that determines whether or not the output signal of the second ultrasonic transducer is received, and a predetermined delay time that receives the output of the receiving circuit. A feedback circuit that outputs to the transmission circuit after a lapse of time, a counter that measures the number of repetitions from transmission to reception and return of the ultrasonic waves, a power control unit that controls the power of the ultrasonic reception circuit, and the number of repetitions. Includes a timer that measures the time from the second and subsequent set values to the end-set value, and an arithmetic unit that calculates the flow rate from the value of the timer, and starts the timer measurement from a stable state. Therefore, a measurement error caused by power-on or a change from low power operation to steady operation that tends to occur at the initial stage of measurement is eliminated, and stable measurement can be performed.
【００１９】（７）受信回路が安定動作か非安定動作か
を判定する回路安定判断手段を備え、前記受信安定判断
手段によって安定動作と判定した後に流量測定を開始す
る。このため受信回路の安定動作のため必要以上の時間
を待つ必要がなく、省電力化できる。( 7 ) A circuit stability judging means for judging whether the receiving circuit is a stable operation or an unstable operation is provided, and the flow rate measurement is started after the receiving stability judging means judges the stable operation. For this reason, it is not necessary to wait an unnecessarily long time for stable operation of the receiving circuit, and power can be saved.
【００２０】（８）受信回路安定判断手段は、被測定流
体の上流方向と下流方向への超音波伝搬時間を測定し、
両測定値を前回の値と比較し、超音波の伝搬時間の測定
結果から受信回路の安定動作を判定する。このため流量
測定と同じ測定回路を使用し安定判断ができ、確実に簡
単な構成で受信回路安定判断手段を実現できる。また上
流方向と下流方向の測定結果から安定判断を行うので、
流体が流れていても判断することができる。( 8 ) The receiving circuit stability judging means measures the ultrasonic wave propagation time in the upstream and downstream directions of the fluid to be measured,
Both measured values are compared with the previous value, and the stable operation of the receiving circuit is determined from the measurement result of the ultrasonic wave propagation time. Therefore, it is possible to perform stability determination by using the same measurement circuit as the flow rate measurement, and it is possible to realize the reception circuit stability determination means with a reliable and simple configuration. In addition, since a stable judgment is made from the measurement results in the upstream and downstream directions,
It can be determined even if the fluid is flowing.
【００２１】[0021]
【実施例】以下、本発明の実施例について図面を用いて
説明する。なお同一符号のものは同一の動作を行うもの
とし重複した説明は行わないものとする。Embodiments of the present invention will be described below with reference to the drawings. It is to be noted that those having the same reference numerals perform the same operation, and duplicate description will not be given.
【００２２】（実施例１）
図１は本発明の実施例１の超音波流量計のブロック図で
ある。また図２は伝搬時間に対する繰り返し回数の設定
値を示す図である。(First Embodiment) FIG. 1 is a block diagram of an ultrasonic flowmeter according to a first embodiment of the present invention. FIG. 2 is a diagram showing set values of the number of repetitions with respect to the propagation time.
【００２３】送信側の超音波周波数の信号を出力する送
信回路１と、被測定流体を伝搬した超音波信号を受信し
電気信号に変換した信号から受信判定し送信回路１に出
力する受信回路２と、超音波の送受信を行う超音波振動
子３、４と送信回路１と受信回路２の接続を送受切り替
えることによって送受の方向を切り替える切り替え器５
と、切り替え器５を制御し送受の方向を交互に切り替え
測定開始信号を送信回路３に出力する制御部６と、測定
開始からの受信回路の信号出力を数えるカウンタ７と、
カウンタ７の値が所定回数に達するまでの時間を計測す
るタイマ８と、タイマ８の値から流量を求める演算部９
と、タイマ８の値に応じてカウンタ７の値を設定する繰
り返し制御部１２を備えている。A transmitting circuit 1 which outputs a signal of ultrasonic frequency on the transmitting side, and a receiving circuit 2 which receives an ultrasonic signal propagating through a fluid to be measured, determines reception from a signal converted into an electric signal, and outputs the signal to the transmitting circuit 1. And a switch 5 for switching the transmission / reception direction by switching the transmission / reception of the connection between the ultrasonic transducers 3 and 4 for transmitting / receiving ultrasonic waves, and the transmission circuit 1 and the reception circuit 2.
And a control unit 6 for controlling the switcher 5 to alternately switch the transmission / reception directions and outputting a measurement start signal to the transmission circuit 3, and a counter 7 for counting the signal output of the reception circuit from the start of measurement.
A timer 8 that measures the time until the value of the counter 7 reaches a predetermined number of times, and an arithmetic unit 9 that calculates the flow rate from the value of the timer 8.
And a repetition control unit 12 that sets the value of the counter 7 according to the value of the timer 8.
【００２４】初めに超音波は超音波振動子３から超音波
振動子４に伝搬させた場合を説明する。First, a case where ultrasonic waves are propagated from the ultrasonic oscillator 3 to the ultrasonic oscillator 4 will be described.
【００２５】まず制御部６が切り替え器５を制御し送信
回路１と超音波振動子３とを接続する、同時に受信回路
２と超音波振動子４とを接続する。次に制御部６は測定
開始信号を送信回路１に出力する。測定開始信号を受け
た送信回路１は超音波振動子３を駆動し、超音波振動子
３は超音波を送信する。送信された超音波は被測定流体
を伝搬し超音波振動子４に伝搬する。超音波振動子４は
超音波を受信し受信信号を受信回路２に出力する。受信
回路２は受信判定を行い超音波の受信を確認し送信回路
１に出力を行う。受信回路２の出力を受けた送信回路１
は再度超音波振動子３を駆動する。この超音波の送信か
ら受信の回数をカウンタ７は数え、この回数がカウンタ
７の設定値（Ｎ回）に達した場合タイマ８を停止させ
る。タイマ８は測定開始からの時間を計測しており、こ
の時のタイマの値ｔ１は超音波の伝搬時間のＮ倍とな
る。次に制御部６は超音波の伝搬させる方向を超音波振
動子４から超音波振動子３に切り替える。そして前回の
測定と同様な動作をさせｔ２を測定する。この値をもと
に演算部９は（式１）によって流量を求める。また、繰
り返し制御部１２はタイマ８の値によって繰り返し回数
Ｎを図２のように増減させる。First, the control unit 6 controls the switch 5 to connect the transmission circuit 1 and the ultrasonic transducer 3, and at the same time, connects the reception circuit 2 and the ultrasonic transducer 4. Next, the control unit 6 outputs a measurement start signal to the transmission circuit 1. The transmission circuit 1 that has received the measurement start signal drives the ultrasonic transducer 3, and the ultrasonic transducer 3 transmits ultrasonic waves. The transmitted ultrasonic wave propagates through the fluid to be measured and propagates to the ultrasonic transducer 4. The ultrasonic transducer 4 receives the ultrasonic wave and outputs a reception signal to the receiving circuit 2. The receiving circuit 2 makes a reception decision, confirms the reception of ultrasonic waves, and outputs the ultrasonic wave to the transmitting circuit 1. Transmitting circuit 1 receiving the output of receiving circuit 2
Drives the ultrasonic transducer 3 again. The counter 7 counts the number of times the ultrasonic waves are transmitted and received, and when the number of times reaches the set value (N times) of the counter 7, the timer 8 is stopped. The timer 8 measures the time from the start of the measurement, and the value t1 of the timer at this time is N times the propagation time of the ultrasonic wave. Next, the control unit 6 switches the ultrasonic wave propagation direction from the ultrasonic vibrator 4 to the ultrasonic vibrator 3. Then, the same operation as the previous measurement is performed to measure t2. Based on this value, the calculation unit 9 obtains the flow rate by (Equation 1). Further, the repetition control unit 12 increases or decreases the number of repetitions N according to the value of the timer 8 as shown in FIG.
【００２６】タイマの分解能が同じであれば、超音波を
被測定流体に伝搬させた伝搬時間によって測定精度が決
まる。この超音波流量計ではタイマの時間ｔ１は、伝搬
時間のＮ倍となる。くり返し回数が固定された従来の超
音波流量計では、必要精度を得るため最も伝搬時間が短
くなる条件において必要精度となるくり返し回数に設定
する必要があった。この繰り返し回数では通常使用する
条件においては、必要以上の間繰り返し動作をするの
で、測定時間が長くなり電力消費が多くなる。本実施例
では、Ｎ×伝搬時間がほぼ一定となるようにＮを設定す
るようにしているので、測定精度を落とすことなく測定
時間を短くでき、低電力化できる。If the resolutions of the timers are the same, the measurement accuracy is determined by the propagation time of the ultrasonic wave propagated in the fluid to be measured. In this ultrasonic flow meter, the time t1 of the timer is N times the propagation time. In the conventional ultrasonic flowmeter in which the number of repetitions is fixed, it is necessary to set the number of repetitions to the required accuracy under the condition that the propagation time is the shortest in order to obtain the required accuracy. With this number of repetitions, under normal conditions of use, the operation is repeated more than necessary, resulting in a long measurement time and high power consumption. In the present embodiment, N is set so that N × propagation time is almost constant, so that the measurement time can be shortened and the power consumption can be reduced without lowering the measurement accuracy.
【００２７】なお本実施例では、受信回路２の出力を数
えくり返し回数を計測したが、くり返し回数に対応した
信号であればよく、受信回路２の出力に限定されること
はない。またＮ×伝搬時間がほぼ一定となるようにＮを
設定するようにしたが、伝搬時間に対するＮの制御は測
定時の流量によって決まる必要測定精度に応じてＮ×伝
搬時間が変化する構成としても電力を小さくすることが
できる。In the present embodiment, the output of the receiving circuit 2 is counted and the number of times of repetition is measured, but any signal corresponding to the number of times of repetition may be used and the output of the receiving circuit 2 is not limited. Further, N is set so that N × propagation time is almost constant, but the control of N with respect to the propagation time may be such that N × propagation time changes according to the required measurement accuracy determined by the flow rate at the time of measurement. The power can be reduced.
【００２８】（実施例２）
図３は本発明の第２の実施例の超音波流量計のブロック
図であり、図４は超音波の伝搬時間と帰還回路１３の遅
延時間との関係を示した図である。(Embodiment 2) FIG. 3 is a block diagram of an ultrasonic flowmeter according to a second embodiment of the present invention, and FIG. 4 shows the relationship between the propagation time of ultrasonic waves and the delay time of the feedback circuit 13. It is a figure.
【００２９】実施例１と異なる点は、受信回路２の出力
を直接送信回路１に帰還するのではなく、所定の遅延時
間経過後に送信回路１に帰還させる帰還回路１３と、帰
還回路１３の遅延時間をタイマ８の値に応じて制御する
遅延制御部１４と、超音波の送信開始から超音波を受信
するまでの時間より所定の時間短い間を計時する第２の
タイマ１５と、帰還回路１３と第２のタイマ１５出力を
受け、遅延時間と伝搬時間より所定時間短い時間の受信
回路２の電力を小さくする電力制御部１６とを備えたと
ころである。その他の部分は実施例１と同等なので説明
を省略する。The difference from the first embodiment is that the output of the receiving circuit 2 is not directly fed back to the transmitting circuit 1, but is fed back to the transmitting circuit 1 after a lapse of a predetermined delay time, and a delay of the feedback circuit 13. The delay control unit 14 that controls the time according to the value of the timer 8, the second timer 15 that measures a time shorter than the time from the start of ultrasonic transmission to the reception of ultrasonic waves by a predetermined time, and the feedback circuit 13 And a power control unit 16 which receives the output of the second timer 15 and reduces the power of the receiving circuit 2 for a predetermined time shorter than the delay time and the propagation time. Since the other parts are the same as those in the first embodiment, the description thereof will be omitted.
【００３０】図３は測定精度を上げるため、図４に示す
ように超音波振動子３から送信し直接超音波振動子４に
伝搬する超音波Ａ（１）と、繰り返しが２回前に超音波
振動子３が送信し超音波送振動子間を反射し一往復半し
た後受信側の超音波振動子で受信される反射波Ａ（−
２）との干渉を避けるため、帰還回路１３によって、遅
延時間Ｔをくり返し動作の中に入れている。遅延時間Ｔ
を適切な値に設定するには、（式２）で示す遅延時間に
設定するとよい（伝搬時間をｔとする）。In FIG. 3, in order to improve the measurement accuracy, the ultrasonic wave A (1) transmitted from the ultrasonic transducer 3 and propagated directly to the ultrasonic transducer 4 as shown in FIG. The reflected wave A (-
In order to avoid interference with 2), the delay time T is put into the repeated operation by the feedback circuit 13. Delay time T
Is set to an appropriate value, the delay time shown in (Equation 2) may be set (propagation time is t).
【００３１】
Ｔ≠ｎｔ・・・・・・（式２）
しかしＴをある時の０．５ｔに設定しても、伝搬時間ｔ
は被測定流体の種類、温度、流速等によって大きく変動
し、Ｔ＝ｎｔとなる条件は必ず存在する、伝搬時間ｔが
この条件となると超音波の干渉のため測定精度は大きく
落ちてしまう。そこで伝搬時間ｔを前回測定したときの
タイマ８の値から逆算し、常に（式２）の条件となるよ
うに遅延制御部１４が帰還回路１３の遅延時間を設定す
る。また、遅延時間は電力消費を小さくするため、超音
波が干渉を起こさない条件で短い時間に設定する。T ≠ nt (Equation 2) However, even if T is set to 0.5t at a certain time, the propagation time t
Varies greatly depending on the type of fluid to be measured, temperature, flow velocity, etc., and there is always a condition of T = nt. If the propagation time t is this condition, the measurement accuracy will be greatly reduced due to the interference of ultrasonic waves. Therefore, the propagation time t is back-calculated from the value of the timer 8 measured last time, and the delay control unit 14 sets the delay time of the feedback circuit 13 so that the condition of (Equation 2) is always satisfied. In addition, the delay time is set to a short time under the condition that ultrasonic waves do not interfere with each other in order to reduce power consumption.
【００３２】また受信回路２の出力を受けた帰還回路１
３は電力制御部１６へ出力し、電力制御部１６は、受信
回路２の電力消費が減少するよう制御を行う。そして、
送信回路１の出力によって動作した第２のタイマ１５が
超音波の伝搬時間よりΔｔｄ短い時間を計時すると電力
制御部１６に信号を出力し、電力制御部１６は受信回路
２の動作を定常状態となるように電力を定常に復帰させ
る。Δｔｄは受信回路の動作が低電力時から定常時に必
要な時間であればよく、電力消費を小さくするためでき
るだけ短い時間に設定している。なお、この実施例では
繰り返しが２回前に送信した超音波との干渉を問題とし
ているが、それ以前に送信した超音波との干渉を避ける
設定とすることでさらに精度が向上する。The feedback circuit 1 receiving the output of the receiving circuit 2
3 is output to the power control unit 16 , and the power control unit 16 controls so that the power consumption of the receiving circuit 2 is reduced. And
When the second timer 15 operated by the output of the transmission circuit 1 measures a time Δtd shorter than the propagation time of the ultrasonic wave, it outputs a signal to the power control unit 16, and the power control unit 16 puts the operation of the reception circuit 2 into a steady state. The power is returned to the steady state so that Δtd may be any time required for the operation of the receiving circuit from low power to steady operation, and is set as short as possible to reduce power consumption. It should be noted that in this embodiment, the repetition has a problem of interference with the ultrasonic wave transmitted two times before, but the accuracy is further improved by setting to avoid the interference with the ultrasonic wave transmitted before that.
【００３３】（実施例３）
図５は本発明の実施例３の受信回路４と周辺回路の詳細
なブロック図であり、図６はピーク検知手段１９の入力
信号を示す図である。(Third Embodiment) FIG. 5 is a detailed block diagram of a receiving circuit 4 and peripheral circuits according to a third embodiment of the present invention, and FIG. 6 is a diagram showing an input signal of the peak detecting means 19.
【００３４】実施例２と異なる点は、受信回路４の中に
あり受信回路４の出力信号を設定した増幅率で増幅する
可変増幅回路１７と、可変増幅回路１７の出力を受け受
信タイミングを検知するタイミング検知回路１８と、タ
イミング検知回路１８の入力信号のピークを検知するピ
ーク検知手段１９と、ピーク検知手段１９の出力を受け
タイミング検知回路１８の入力信号ピークを一定に保つ
受信信号安定手段２０とを備え、ピーク検知手段１９の
出力を受けた電力制御部２１によって受信回路４の電力
を低減する構成としたところである。The difference from the second embodiment is that the receiving circuit 4 has a variable amplifying circuit 17 for amplifying the output signal of the receiving circuit 4 with a set amplification factor, and an output of the variable amplifying circuit 17 is received to detect a receiving timing. Timing detection circuit 18, peak detection means 19 for detecting the peak of the input signal of the timing detection circuit 18, and received signal stabilizing means 20 for receiving the output of the peak detection means 19 and keeping the input signal peak of the timing detection circuit 18 constant. And the power control unit 21 receiving the output of the peak detection unit 19 reduces the power of the receiving circuit 4.
【００３５】受信回路４は入力信号が小さいあるいは大
きい場合であっても、同じタイミングで受信判定を行う
ため、タイミング検知回路１８の入力信号のピークレベ
ルをピーク検知手段１９によって検知し、次の測定のと
きにその検知レベルを受けた受信信号安定手段２０が可
変増幅回路１７の増幅率を変えタイミング検知回路の受
信レベルを安定化している。Even if the input signal is small or large, the receiving circuit 4 determines the reception at the same timing. Therefore, the peak level of the input signal of the timing detecting circuit 18 is detected by the peak detecting means 19, and the next measurement is performed. At that time, the reception signal stabilizing means 20 receiving the detection level changes the amplification factor of the variable amplifier circuit 17 to stabilize the reception level of the timing detection circuit.
【００３６】図６のＣで受信タイミングを検知し帰還回
路による遅延動作を行うが、受信タイミングの検知と同
時に受信回路４の電力を小さくしたのでは図６の破線で
示すような波形となる。そのため、本来図６のＰをタイ
ミング検知手段の入力信号のピークとしなければならな
いが、Ｐ’と誤判定してしまい、正常な測定を行うこと
ができない。そこで、ピーク検知手段１９の出力を電力
制御部２１に送ることによって、ピークレベルを検知す
ると同時に受信回路４の電力を小さくしている。6C, the reception timing is detected and the delay operation is performed by the feedback circuit. However, if the power of the reception circuit 4 is reduced at the same time as the reception timing is detected, the waveform becomes as shown by the broken line in FIG. Therefore, although P in FIG. 6 should originally be set as the peak of the input signal of the timing detection means, it is erroneously determined as P ′ and normal measurement cannot be performed. Therefore, the output of the peak detector 19 is sent to the power controller 21 to detect the peak level and at the same time reduce the power of the receiving circuit 4.
【００３７】（実施例４）
図７は本発明の実施例４の超音波流量計のブロック図で
あり、図８は電力制御部２２による電力制御のタイミン
グを示す図である。(Embodiment 4) FIG. 7 is a block diagram of an ultrasonic flowmeter according to Embodiment 4 of the present invention, and FIG. 8 is a diagram showing the timing of power control by the power controller 22.
【００３８】実施例２と異なる点は、電力制御部２２に
カウンタ７の出力を入力したところであり、電力制御部
２２はカウンタ７の出力が小さいときには、前記電力を
抑制を解除するタイミングを早くする。つまりΔｔｄの
値を大きく設定する。カウンタの値がおおきくなると、
Δｔｄの値を通常の値とするところである。The difference from the second embodiment is that the output of the counter 7 is input to the power control unit 22, and when the output of the counter 7 is small, the power control unit 22 advances the timing of releasing the suppression of the power. . That is, the value of Δtd is set large. When the value of the counter becomes large,
This is where the value of Δtd is set to a normal value.
【００３９】電源を長時間切るあるいは小さくした後に
測定を行う場合、回路各部の電圧や温度が測定時と異な
るため、測定の結果が安定しない。そのため測定前に電
源を定常状態とし一定時間経過後に測定を行う必要があ
った。When the measurement is performed after the power source is turned off or reduced for a long time, the voltage and temperature of each part of the circuit are different from those at the time of measurement, and the measurement result is not stable. Therefore, it was necessary to make the power supply a steady state before the measurement and perform the measurement after a certain period of time.
【００４０】そこで受信回路の電源投入時あるいは電力
抑制動作から定常動作への変更時に、受信回路２の動作
が安定となるまでの時間が長い測定初期は、早期に電力
抑制を解除し、あるいは電力を低減せずに動作させ、超
音波信号の受信時には受信回路の動作を安定させる。Therefore, when the power of the receiving circuit is turned on or when the power suppressing operation is changed to the steady operation, it takes a long time for the operation of the receiving circuit 2 to become stable. The operation of the receiving circuit is stabilized when the ultrasonic signal is received.
【００４１】（実施例５）
図９は本発明の実施例５の超音波流量計のブロック図で
ある。(Fifth Embodiment) FIG. 9 is a block diagram of an ultrasonic flowmeter according to a fifth embodiment of the present invention.
【００４２】実施例２と異なる点は、タイマ８のスター
トとストップをカウンタ７の出力信号で行っているとこ
ろである。The difference from the second embodiment is that the timer 8 is started and stopped by the output signal of the counter 7.
【００４３】電源を長時間切るあるいは小さくした後に
測定を行う場合、回路各部の電圧や温度が測定時と異な
るため、測定の結果が安定しない。When the measurement is performed after turning off the power supply for a long time or after reducing the power supply, the result of the measurement is not stable because the voltage and temperature of each part of the circuit are different from those during the measurement.
【００４４】そこで、本発明では簡単な構成によって、
最も不安定な状態である測定開始から１〜数回くり返し
動作の間を測定しない構成とし、その後タイマ８による
計時を行うことによって、回路各部が測定時と同等の状
態となり、測定精度が向上する。Therefore, according to the present invention, a simple structure is used.
The most unstable state is set such that the measurement is not performed for a period of one to several times from the start of measurement, and then the timer 8 measures the time, so that each circuit unit becomes in the same state as the measurement time, and the measurement accuracy is improved. .
【００４５】（実施例６）
図１０は本発明の実施例６の超音波流量計のブロック図
である。(Sixth Embodiment) FIG. 10 is a block diagram of an ultrasonic flowmeter according to a sixth embodiment of the present invention.
【００４６】実施例２と異なる点は、被測定流体の温度
を検知する温度検知部２４と、被測定流体の種類を判別
する流体設定スイッチ２５と、温度検知部２４、流体判
別手段２５の出力に応じて受信回路２の電力を制御する
タイミングを変更する電力制御部２６を備えたところで
ある。The difference from the second embodiment is that the temperature detecting section 24 for detecting the temperature of the fluid to be measured, the fluid setting switch 25 for discriminating the kind of the fluid to be measured, the temperature detecting section 24 and the output of the fluid discriminating means 25. The power control unit 26 that changes the timing for controlling the power of the receiving circuit 2 according to
【００４７】電力制御部２６は被測定流体を伝搬してく
る超音波の受信タイミングよりΔｔｄ短い時間早く受信
回路２を定常動作とするように電力制御する。超音波の
伝搬時間は被測定流体や、被測定流体の温度等によって
大きく変動するため、電力制御部２６は、温度検知部２
４の出力、流体設定スイッチ２５の出力によって伝搬時
間を求め、受信回路２の電力を伝搬時間よりΔｔｄ早く
定常状態に復帰させる。The power control section 26 controls the power so that the receiving circuit 2 is put into a steady operation earlier than the reception timing of the ultrasonic waves propagating through the fluid to be measured by a time shorter than Δtd. Since the propagation time of ultrasonic waves greatly varies depending on the fluid to be measured, the temperature of the fluid to be measured, and the like, the power control unit 26 causes the temperature detection unit 2 to operate.
4 and the output of the fluid setting switch 25, the propagation time is obtained, and the power of the receiving circuit 2 is returned to the steady state earlier by Δtd than the propagation time.
【００４８】なお流体設定スイッチ２５は、ガスの種類
を自動検出するガスセンサ、たとえばＣＯ２センサなど
であってもかまわない。The fluid setting switch 25 may be a gas sensor that automatically detects the type of gas, such as a CO2 sensor.
【００４９】（実施例７）
図１１は本発明の実施例７の超音波流量計のブロック図
である。(Seventh Embodiment) FIG. 11 is a block diagram of an ultrasonic flowmeter according to a seventh embodiment of the present invention.
【００５０】実施例２と異なる点は、超音波の伝搬時間
を前回測定時のタイマ８出力から求め、超音波の伝搬時
間に応じて受信回路２の出力を無効とするタイミングを
制御する出力無効回路２７を備えたところである。The difference from the second embodiment is that the ultrasonic wave propagation time is obtained from the output of the timer 8 at the time of the previous measurement, and the output is invalidated for controlling the timing of invalidating the output of the receiving circuit 2 according to the ultrasonic wave propagation time. The circuit 27 is provided.
【００５１】出力無効回路２７は制御部６が測定開始信
号を出力するか、受信回路２が超音波の受信判定を行っ
た後に受信回路２の出力を無効となるようにし、超音波
の伝搬時間を前回測定時のタイマ８出力から求め、受信
回路に超音波信号が入力される直前に受信回路の出力を
有効となるように制御する。The output invalidating circuit 27 disables the output of the receiving circuit 2 after the control unit 6 outputs the measurement start signal or after the receiving circuit 2 determines whether the ultrasonic wave is received. Is calculated from the output of the timer 8 at the time of the previous measurement, and the output of the receiving circuit is controlled to be valid immediately before the ultrasonic signal is input to the receiving circuit.
【００５２】このような制御によって、流体の変化や流
体の温度変化によって超音波の伝搬時間が変化した場合
であっても、超音波を受信するタイミング以外の雑音に
よる誤動作を防止する。特に受信回路の電力を増減させ
る構成において、電力を変更時に発生する回路の誤動作
で発生する雑音による誤動作を防止する。By such control, even when the ultrasonic wave propagation time changes due to the change of the fluid or the temperature of the fluid, malfunction due to noise other than the timing of receiving the ultrasonic wave is prevented. In particular, in a configuration in which the power of the receiving circuit is increased or decreased, malfunction due to noise generated by malfunction of the circuit that occurs when power is changed is prevented.
【００５３】（実施例８）
図１２は本発明の実施例８の超音波流量計のブロック図
である。(Embodiment 8) FIG. 12 is a block diagram of an ultrasonic flowmeter according to Embodiment 8 of the present invention.
【００５４】実施例２と異なる点は、受信回路安定判断
手段２８によって回路の安定動作を判定した後に流量測
定する構成としているところである。The difference from the second embodiment is that the flow rate is measured after the stable operation of the circuit is judged by the receiving circuit stability judging means 28.
【００５５】受信回路安定判断手段２８は、下流方向、
上流方向への測定結果であるｔ１、ｔ２の逆数和を前回
測定したときのもとの比較する。この値は、（式３）に
示すように音速に比例した値となる。The receiving circuit stability judging means 28 is
The reciprocal sum of t1 and t2, which is the measurement result in the upstream direction, is compared with the original value when the previous measurement was performed. This value is a value proportional to the speed of sound as shown in (Equation 3).
【００５６】超音波振動子間の距離をＬ、音速をｃ、流
速をｖとすると、
１／ｔ１＋１／ｔ２
＝（ｖ−ｃ）／Ｌ＋（ｖ＋ｃ）／Ｌ
＝（２／Ｌ）×ｖ・・・・・・・・・・・（式３）
被測定流体またはその温度が大きく変動しないかぎり、
音速は短時間では大きく変動することがないため、この
逆数和の値が大きく変動することはない。このため、前
回の値と近いかどうかを受信回路安定判断手段２８で判
断することによって、受信回路２が前回測定時と同等の
計測動作をしているかどうか判定することができる。そ
こで、逆数和の値が前回測定値に近ければ受信回路２が
安定動作状態となったと判断し流量計測を開始する。When the distance between the ultrasonic transducers is L, the speed of sound is c, and the flow velocity is v, 1 / t1 + 1 / t2 = (v−c) / L + (v + c) / L = (2 / L) × v · (Equation 3) Unless the fluid to be measured or its temperature fluctuates significantly,
Since the speed of sound does not change significantly in a short time, the value of this reciprocal sum does not change significantly. Therefore, it is possible to determine whether or not the receiving circuit 2 is performing a measurement operation equivalent to that at the time of the previous measurement by determining by the receiving circuit stability determination means 28 whether the value is close to the previous value. Therefore, if the value of the reciprocal sum is close to the previously measured value, it is determined that the receiving circuit 2 is in a stable operation state, and the flow rate measurement is started.
【００５７】以上のように、本実施の形態によれば次の
効果が得られる。 As described above, according to the present embodiment, the following
The effect is obtained.
【００５８】（１）超音波を送信する第１の超音波振動
子と、前記第１の超音波振動子を駆動する送信回路と、
被測定流体を伝搬した超音波を受信する第２の超音波振
動子と、前記第２の超音波振動子の出力信号から受信判
定する受信回路と、前記受信回路の出力を受け所定の遅
延時間経過後に前記送信回路へ出力する帰還回路と、前
記超音波の送信から受信そして帰還までの繰り返しの回
数を計測するカウンタと、前記繰り返しの回数が所定回
数に達するまでの時間を計測するタイマと、前記タイマ
の値から流量を求める演算部と、伝搬時間が長くなるに
対応してくり返し回数をへらすくり返し制御部によっ
て、伝搬時間が長くなった場合に精度を必要以上にあげ
ることなく繰り返し回数が少なくなり、伝搬時間が短く
なった場合には、くり返し回数が増えるので精度が落ち
ることがない。つまり必要以上の繰り返し測定をおこな
う必要がないので、低電力化できる。(1) A first ultrasonic transducer for transmitting ultrasonic waves, and a transmission circuit for driving the first ultrasonic transducer,
A second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, a receiving circuit that determines whether or not the output signal of the second ultrasonic transducer is received, and a predetermined delay time that receives the output of the receiving circuit. A feedback circuit that outputs to the transmission circuit after a lapse of time, a counter that measures the number of repetitions from transmission of the ultrasonic waves to reception and feedback, and a timer that measures the time until the number of repetitions reaches a predetermined number, By the calculation unit that obtains the flow rate from the value of the timer and the repeat control unit that reduces the number of repeats as the propagation time increases, the number of repetitions is reduced without increasing the accuracy when the propagation time is longer than necessary. Therefore, when the propagation time becomes short, the number of times of repetition increases, so that the accuracy does not decrease. In other words, it is not necessary to carry out repeated measurement more than necessary, so that the power consumption can be reduced.
【００５９】（２）伝搬時間によって遅延制御部が遅延
時間を変化させるため、大きく伝搬時間が変化した場合
であっても、超音波振動子間を反射した後第２の超音波
振動子で受信される反射波と直接第１の超音波振動子か
ら送信された超音波を第２の超音波振動子で受信するタ
イミングとを外すことができるので、伝搬時間の短い流
体から長い流体まで正確な測定を行うことができる。ま
た遅延時間を反射波と直接波が重ならない最短の時間に
設定することができるので、測定時間が短くなり低電力
化できる。(2) Since the delay control unit changes the delay time according to the propagation time, even if the propagation time largely changes, it is reflected by the ultrasonic transducers and then received by the second ultrasonic transducer. Since the reflected wave to be generated and the timing at which the ultrasonic wave directly transmitted from the first ultrasonic transducer is received by the second ultrasonic transducer can be deviated, it is possible to accurately obtain from a fluid having a short propagation time to a fluid having a long propagation time. A measurement can be made. Moreover, since the delay time can be set to the shortest time during which the reflected wave and the direct wave do not overlap, the measurement time can be shortened and the power consumption can be reduced.
【００６０】（３）超音波の伝搬時間より所定時間短い
時間と前記遅延時間とを含む間前記受信回路の電力を低
減または遮断させる電力制御部によって、遅延時間と伝
搬時間より所定時間短い間との両方の時間受信回路の電
力を低減できるので、より低電力化できる。[0060] (3) by ultrasonic power reduction or power control unit Ru is cut off between said receiver circuit including a short time and the delay time predetermined time than the propagation time of short predetermined than the propagation time and the delay time period Since the electric power of the receiving circuit can be reduced both during the time period and during the time period, the electric power can be further reduced.
【００６１】（４）ピーク検知手段がピークレベルを検
知した後から前記第２の超音波振動子に超音波が受信さ
れる一定時間前まで電力制御手段が受信回路の電力を低
減するので、ピーク検知を行った後に受信回路の電力を
低減し、ピーク検知手段が超音波信号のピークレベルを
正確に検知する。このため受信信号のピークを一定の値
とすることができる。さらに受信波のピークを一定にた
もつ動作を行った状態で長い時間受信回路の電力を低減
できるので、省電力化できる。(4) Since the power control means reduces the power of the receiving circuit from the time when the peak detecting means detects the peak level until a certain time before ultrasonic waves are received by the second ultrasonic transducer, After the detection, the power of the receiving circuit is reduced, and the peak detecting means accurately detects the peak level of the ultrasonic signal. Therefore, the peak of the received signal can be set to a constant value. Further, the power of the receiving circuit can be reduced for a long time in the state where the operation with the peak of the received wave is performed, so that the power can be saved.
【００６２】（５）少なくとも超音波の伝搬開始から伝
搬時間より所定の時間短い間前記受信回路の電力を抑制
する電力制御部によって、受信回路の電源投入時あるい
は電力抑制動作から定常動作への変更時に、受信回路の
動作が安定となるまでの時間が長い測定初期は早期に電
力抑制を解除し、くり返し回数が多くなり受信回路の動
作が安定となるまでの時間が短い時には電力抑制の時間
を長くする制御によって、必要以上の時間受信回路を電
力の大きい定常動作させる必要がないので、省電力化で
きる。(5) At least when the power of the receiving circuit is turned on or the power suppressing operation is changed to the steady operation by the power control unit that suppresses the electric power of the receiving circuit at least for a predetermined time shorter than the propagation time from the start of ultrasonic wave propagation. Sometimes, it takes a long time for the operation of the receiver circuit to be stable.In the initial measurement, the power suppression is canceled early, and when the time for the receiver circuit to stabilize becomes short and the operation time of the receiver circuit is short, the time for the power suppression is reduced. The lengthening control does not require the receiving circuit to operate with high power for a longer period of time than necessary, so power consumption can be saved.
【００６３】（６）前記繰り返し回数が２回目以降の設
定した値から終了設定した値までの時間を計測するタイ
マによって、測定初期に発生しやすい電源投入あるいは
低電力動作から定常動作への変化によって起こる測定誤
差を排除できる。(6) By the timer that measures the time from the set value of the second and subsequent repeat times to the set value after the end of the repetition, the power-on which is likely to occur in the initial stage of measurement or the change from the low power operation to the steady operation The measurement error that occurs can be eliminated.
【００６４】（７）温度検知部で検知した被測定流体の
温度に応じて受信回路の電力を制御する電力制御部によ
って、温度変化による超音波伝搬時間の変化、受信回路
の温度特性にあわせて受信回路の電力を増減するので、
省電力化できる。また超音波の伝搬時間を求める手段を
設ける必要がなく回路構成を簡略化できる。(7) The power control unit for controlling the power of the receiving circuit according to the temperature of the fluid to be measured detected by the temperature detecting unit adjusts the ultrasonic wave propagation time due to the temperature change and the temperature characteristic of the receiving circuit. Since the power of the receiving circuit is increased or decreased,
Power saving can be achieved. Further, it is not necessary to provide means for obtaining the propagation time of ultrasonic waves, and the circuit configuration can be simplified.
【００６５】（８）流体判別手段で判定した流体に応じ
て受信回路の電力を制御する電力制御手段によって、流
体の種類による超音波伝搬時間の変化にあわせて受信回
路の電力を増減するタイミングを変えるので、受信時に
は受信回路出力を安定化できかつ省電力化できる。また
超音波の伝搬時間を求める手段を設ける必要がなく回路
構成を簡略化できる。(8) The power control means for controlling the electric power of the receiving circuit according to the fluid judged by the fluid judging means adjusts the timing of increasing or decreasing the electric power of the receiving circuit according to the change of the ultrasonic wave propagation time depending on the kind of the fluid. Since it is changed, the output of the receiving circuit can be stabilized and power can be saved during reception. Further, it is not necessary to provide means for obtaining the propagation time of ultrasonic waves, and the circuit configuration can be simplified.
【００６６】（９）超音波の伝搬時間に応じて受信回路
の出力を無効にするタイミングを制御する出力無効回路
によって、流体の変化や流体の温度変化によって超音波
の伝搬時間が変化した場合であっても、超音波を受信す
るタイミング以外の雑音による誤動作を防止できるの
で、測定回数を減らすことができ、省電力化できる。特
に受信回路の電力を増減させる構成において、電力を変
更時に発生する回路の誤動作で発生する雑音による誤動
作を防止できる。(9) In the case where the ultrasonic wave propagation time is changed due to the change of the fluid or the temperature change of the fluid by the output invalidation circuit which controls the timing of invalidating the output of the receiving circuit according to the propagation time of the ultrasonic wave. Even if there is, an erroneous operation due to noise other than the timing of receiving the ultrasonic waves can be prevented, so that the number of measurements can be reduced and power consumption can be saved. In particular, in the configuration in which the power of the receiving circuit is increased or decreased, it is possible to prevent malfunction due to noise generated by malfunction of the circuit that occurs when power is changed.
【００６７】（１０）受信回路安定判断手段によって回
路の安定動作を判定した後に流量測定する回路安定判断
手段によって、受信回路の安定動作のため必要以上の時
間を待つ必要がなく、省電力化できる。(10) The circuit stability determining means for measuring the flow rate after determining the stable operation of the circuit by the receiving circuit stability determining means does not need to wait an unnecessarily long time for the stable operation of the receiving circuit and can save power. .
【００６８】（１１）受信回路安定判断手段は超音波の
伝搬時間の測定結果から受信回路の安定動作を判定する
ので、流量測定と同じ測定回路を使用し安定判断がで
き、確実に簡単な構成で受信回路安定判断手段を実現で
きる。また上流方向と下流方向の測定結果から安定判断
を行うので、流体が流れていても判断することができ
る。(11) Since the receiving circuit stability judging means judges the stable operation of the receiving circuit from the measurement result of the ultrasonic wave propagation time, it is possible to make a stable judgment by using the same measuring circuit as the flow rate measurement, and a surely simple structure. The receiver circuit stability determination means can be realized with. Further, since a stable determination is made based on the measurement results in the upstream direction and the downstream direction, it can be determined even if the fluid is flowing.
【００６９】[0069]
【発明の効果】【The invention's effect】
以上のように本発明によれば、必要以上As described above, according to the present invention,
の繰り返し測定をおこなう必要がないので、低電力化でSince there is no need to perform repeated measurement of
きる。Wear.
【図１】本発明の実施例１の超音波流量計のブロック図FIG. 1 is a block diagram of an ultrasonic flowmeter according to a first embodiment of the present invention.
【図２】同流量計の伝搬時間に対する繰り返し回数の設
定値を示す図FIG. 2 is a diagram showing set values for the number of repetitions with respect to the propagation time of the same flow meter.
【図３】本発明の実施例２の超音波流量計のブロック図FIG. 3 is a block diagram of an ultrasonic flowmeter according to a second embodiment of the present invention.
【図４】同流量計の超音波の伝搬時間と帰還回路１３の
遅延時間との関係を示した図FIG. 4 is a diagram showing a relationship between an ultrasonic wave propagation time of the flowmeter and a delay time of the feedback circuit 13.
【図５】本発明の実施例３の超音波流量計の受信回路４
と周辺回路の詳細なブロック図FIG. 5 is a receiving circuit 4 of the ultrasonic flowmeter according to the third embodiment of the present invention.
And detailed block diagram of peripheral circuits
【図６】同流量計のピーク検知手段１９の入力信号を示
す図FIG. 6 is a diagram showing an input signal of a peak detecting means 19 of the same flow meter.
【図７】本発明の実施例４の超音波流量計のブロック図FIG. 7 is a block diagram of an ultrasonic flowmeter according to a fourth embodiment of the present invention.
【図８】同流量計の電力制御部２２による電力制御のタ
イミングを示す図FIG. 8 is a diagram showing a timing of power control by a power control unit 22 of the flow meter.
【図９】本発明の実施例５の超音波流量計のブロック図FIG. 9 is a block diagram of an ultrasonic flowmeter according to a fifth embodiment of the present invention.
【図１０】本発明の実施例６の超音波流量計のブロック
図FIG. 10 is a block diagram of an ultrasonic flowmeter according to a sixth embodiment of the present invention.
【図１１】本発明の実施例７の超音波流量計のブロック
図FIG. 11 is a block diagram of an ultrasonic flowmeter according to a seventh embodiment of the present invention.
【図１２】本発明の実施例８の超音波流量計のブロック
図FIG. 12 is a block diagram of an ultrasonic flowmeter according to an eighth embodiment of the present invention.
【図１３】従来の超音波流量計のブロック図FIG. 13 is a block diagram of a conventional ultrasonic flowmeter.
１ 送信回路 ２ 受信回路 ３ 第１の超音波振動子 ４ 第２の超音波振動子 ５ 切り替え器 ６ 制御部 ７ カウンタ ８ タイマ ９ 演算部 １２ 繰り返し制御部 １３ 帰還回路 １４ 遅延制御部 １５ 第２のタイマ １６ 電力制御部 １７ 可変増幅回路 １８ タイミング検知回路 １９ ピーク検知手段 ２０ 受信信号安定手段 ２１ 電力制御部 ２２ 電力制御部 ２４ 温度検知部 ２５ 流体設定スイッチ ２６ 電力制御部 ２７ 出力無効回路 ２８ 受信安定判断手段 1 transmitter circuit 2 Receiver circuit 3 First ultrasonic transducer 4 Second ultrasonic transducer 5 switch 6 control unit 7 counter 8 timer 9 Operation part 12 Repeat control unit 13 Feedback circuit 14 Delay control unit 15 Second timer 16 Power control unit 17 Variable amplifier circuit 18 Timing detection circuit 19 Peak detection means 20 Received signal stabilizing means 21 Power control unit 22 Power control unit 24 Temperature detector 25 Fluid setting switch 26 Power control unit 27 Output invalid circuit 28 Means for judging stability of reception
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G01F 1/66 101 ─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) G01F 1/66 101
Claims (8)
前記第１の超音波振動子を駆動する送信回路と、被測定
流体を伝搬した超音波を受信する第２の超音波振動子
と、前記第２の超音波振動子の出力信号から受信判定す
る受信回路と、前記受信回路の出力を受け所定の遅延時
間経過後に前記送信回路へ出力する帰還回路と、前記超
音波の送信から受信そして帰還までの繰り返しの回数を
計測するカウンタと、前記繰り返しの回数が所定回数に
達するまでの時間を計測するタイマと、前記タイマの値
から流量を求める演算部と、前記超音波が前記第１の超
音波振動子から前記第２の超音波振動子に達するまでの
伝搬時間の長さに応じて前記繰り返しの回数を増減し、
伝搬時間と繰り返し回数の積がほぼ一定となるようにす
る繰り返し制御部を備えた超音波流量計。1. A first ultrasonic transducer for transmitting ultrasonic waves,
A transmission circuit that drives the first ultrasonic transducer, a second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, and reception determination from the output signal of the second ultrasonic transducer A receiving circuit, a feedback circuit that receives the output of the receiving circuit and outputs it to the transmitting circuit after a predetermined delay time has passed, a counter that measures the number of repetitions from the transmission of the ultrasonic waves to the reception and the return of the ultrasonic waves, A timer that measures the time until the number of times reaches a predetermined number, an arithmetic unit that obtains a flow rate from the value of the timer, and the ultrasonic wave reaches the second ultrasonic vibrator from the first ultrasonic vibrator. Increase or decrease the number of repetitions according to the length of the propagation time up to,
An ultrasonic flowmeter equipped with a repetition control unit that keeps the product of the propagation time and the number of repetitions substantially constant.
前記第１の超音波振動子を駆動する送信回路と、被測定
流体を伝搬した超音波を受信する第２の超音波振動子
と、前記第２の超音波振動子の出力信号から受信判定す
る受信回路と、前記受信回路の出力を受け所定の遅延時
間経過後に前記送信回路へ出力する帰還回路と、前記超
音波の送信から受信そして帰還までの繰り返しの回数を
計測するカウンタと、前記繰り返しの回数が所定回数に
達するまでの時間を計測するタイマと、前記タイマの値
から流量を求める演算部と、前記超音波が前記弟１の超
音波振動子から前記第２の超音波振動子に達するまでの
伝搬時間に応じて前記遅延時間を制御し、遅延時間を伝
搬時間の整数倍に一致しない値とする遅延制御部を備え
た超音波流量計。2. A first ultrasonic transducer for transmitting ultrasonic waves,
A transmission circuit that drives the first ultrasonic transducer, a second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, and reception determination from the output signal of the second ultrasonic transducer A receiving circuit, a feedback circuit that receives the output of the receiving circuit and outputs it to the transmitting circuit after a predetermined delay time has passed, a counter that measures the number of repetitions from the transmission of the ultrasonic waves to the reception and the return of the ultrasonic waves, A timer that measures the time until the number of times reaches a predetermined number, a calculation unit that obtains a flow rate from the value of the timer, and the ultrasonic wave reaches the second ultrasonic vibrator from the ultrasonic vibrator of the younger brother 1. The ultrasonic flowmeter provided with a delay control unit that controls the delay time according to the propagation time up to and sets the delay time to a value that does not match an integral multiple of the propagation time.
前記第１の超音波振動子を駆動する送信回路と、被測定
流体を伝搬した超音波を受信する第２の超音波振動子
と、前記第２の超音波振動子の出力信号から受信判定す
る受信回路と、前記受信回路の出力を受け所定の遅延時
間経過後に前記送信回路へ出力する帰還回路と、前記超
音波の送信から受信そして帰還までの繰り返しの回数を
計測するカウンタと、前記繰り返しの回数が所定回数に
達する時間を計測するタイマと、前記タイマの値から流
量を求める演算部と、超音波の受信後、超音波の伝搬時
間より所定時間短い時間と前記遅延時間とを含む間前記
受信回路の電力消費を減少するよう制御する電力制御部
とを備えた超音波流量計。3. A first ultrasonic transducer for transmitting ultrasonic waves,
A transmission circuit that drives the first ultrasonic transducer, a second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, and reception determination from the output signal of the second ultrasonic transducer A receiving circuit, a feedback circuit that receives the output of the receiving circuit and outputs it to the transmitting circuit after a predetermined delay time has passed, a counter that measures the number of repetitions from the transmission of the ultrasonic waves to the reception and the return of the ultrasonic waves, A timer that measures the time at which the number of times reaches a predetermined number, a calculation unit that obtains a flow rate from the value of the timer, a period that includes a time shorter than the propagation time of the ultrasonic wave by a predetermined time and the delay time after the ultrasonic wave is received. An ultrasonic flowmeter, comprising: a power control unit that controls to reduce power consumption of a receiving circuit.
前記第１の超音波振動子を駆動する送信回路と、被測定
流体を伝搬した超音波を受信する第２の超音波振動子
と、前記第２の超音波振動子の出力信号から受信判定す
る受信回路と、前記受信回路の中にあり前記第２の超音
波振動子の出力信号を直接あるいは信号処理の後に受け
超音波の受信タイミングを検知するタイミング検知回路
と、前記タイミング検知回路の出力を受け所定の遅延時
間経過後に前記送信回路へ出力する帰還回路と、前記超
音波の送信から受信そして帰還までの繰り返しの回数を
計測するカウンタと、前記繰り返しの回数が所定回数に
達する時間を計測するタイマと、前記タイマの値から流
量を求める演算部と、前記タイミング検知回路入力信号
のピークを検知するピーク検知手段と、前記ピーク検知
手段の出力を受け前記タイミング検知回路入力信号のピ
ークを一定に保つ受信信号安定手段と、前記受信回路の
電力を低減する電力制御部とを備え、前記ピーク検知手
段がピークレベルを検知した後から前記第２の超音波振
動子に超音波が受信される一定時間前まで前記電力制御
手段が前記受信回路の電力を低減する超音波流量計。4. A first ultrasonic transducer for transmitting ultrasonic waves,
A transmission circuit that drives the first ultrasonic transducer, a second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, and reception determination from the output signal of the second ultrasonic transducer A reception circuit, a timing detection circuit in the reception circuit for receiving the output signal of the second ultrasonic transducer directly or after the signal processing and detecting the reception timing of the ultrasonic wave, and an output of the timing detection circuit. A feedback circuit that outputs to the transmission circuit after a lapse of a predetermined delay time, a counter that measures the number of repetitions of the ultrasonic wave from transmission to reception and feedback, and a time when the number of repetitions reaches a predetermined number of times A timer, an operation unit for obtaining a flow rate from the value of the timer, a peak detection unit for detecting a peak of the timing detection circuit input signal, and a unit for receiving an output of the peak detection unit. The second ultrasonic wave is provided with a reception signal stabilizing unit that keeps the peak of the timing detection circuit input signal constant and a power control unit that reduces the power of the reception circuit, after the peak detection unit detects the peak level. An ultrasonic flowmeter in which the power control unit reduces the power of the receiving circuit until a certain time before ultrasonic waves are received by the vibrator.
前記第１の超音波振動子を駆動する送信回路と、被測定
流体を伝搬した超音波を受信する第２の超音波振動子
と、前記第２の超音波振動子の出力信号から受信判定す
る受信回路と、前記受信回路の出力を受け所定の遅延時
間経過後に前記送信回路へ出力する帰還回路と、前記超
音波の送信から受信そして帰還までの回数を計測するカ
ウンタと、前記繰り返しの回数が所定回数に達する時間
を計測するタイマと、前記タイマの値から流量を求める
演算部と、少なくとも超音波の伝搬開始から伝搬時間よ
り所定の時間短い間前記受信回路の電力を抑制する電力
制御部とを備え、繰り返し初期は前記電力を抑制を解除
するタイミングを早くする超音波流量計。5. A first ultrasonic transducer for transmitting ultrasonic waves,
A transmission circuit that drives the first ultrasonic transducer, a second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, and reception determination from the output signal of the second ultrasonic transducer A receiving circuit, a feedback circuit that receives the output of the receiving circuit and outputs it to the transmitting circuit after a predetermined delay time elapses, a counter that measures the number of times from transmission of the ultrasonic waves to reception and return, and the number of repetitions. A timer that measures the time to reach a predetermined number of times, an arithmetic unit that obtains a flow rate from the value of the timer, and a power control unit that suppresses the power of the receiving circuit at least for a predetermined time shorter than the propagation time from the start of ultrasonic wave propagation. And an ultrasonic flow meter that accelerates the timing of releasing the suppression of the electric power in the initial period of repetition.
前記第１の超音波振動子を駆動する送信回路と、被測定
流体を伝搬した超音波を受信する第２の超音波振動子
と、前記第２の超音波振動子の出力信号から受信判定す
る受信回路と、前記受信回路の出力を受け所定の遅延時
間経過後に前記送信回路へ出力する帰還回路と、前記超
音波の送信から受信そして帰還までの繰り返しの回数を
測定するカウンタと、前記超音波受信回路の電力を制御
する電力制御部と、前記繰り返し回数が２回目以降の設
定した値から終了設定した値までの時間を計測するタイ
マと、前記タイマの値から流量を求める演算部とを備え
た超音波流量計。6. A first ultrasonic transducer for transmitting ultrasonic waves,
A transmission circuit that drives the first ultrasonic transducer, a second ultrasonic transducer that receives the ultrasonic waves that have propagated through the fluid to be measured, and reception determination from the output signal of the second ultrasonic transducer A receiver circuit, a feedback circuit that receives the output of the receiver circuit and outputs the output to the transmitter circuit after a lapse of a predetermined delay time, a counter that measures the number of repetitions of the ultrasonic wave from transmission to reception and return, and the ultrasonic wave. A power control unit that controls the power of the receiving circuit, a timer that measures the time from the set value after the second repetition to a set value after the repetition, and an arithmetic unit that calculates the flow rate from the value of the timer are provided. Ultrasonic flowmeter.
する回路安定判断手段を備え、前記受信安定判断手段に
よって安定動作と判定した後に流量を測定する請求項１
から６のいずれか１項記載の超音波流量計。7. A circuit stability judging means for judging whether the receiving circuit is a stable operation or an unstable operation, and the flow rate is measured after the receiving stability judging means judges a stable operation.
7. The ultrasonic flowmeter according to any one of 1 to 6 .
流方向と下流方向への超音波伝搬時間を測定し、両測定
値を前回の値と比較する請求項７記載の超音波流量計。8. The ultrasonic flowmeter according to claim 7 , wherein the receiving circuit stability determining means measures ultrasonic wave propagation time in the upstream and downstream directions of the fluid to be measured and compares both measured values with previous values. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21151197A JP3473341B2 (en) | 1997-08-06 | 1997-08-06 | Ultrasonic flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21151197A JP3473341B2 (en) | 1997-08-06 | 1997-08-06 | Ultrasonic flow meter |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003195041A Division JP2003344130A (en) | 2003-07-10 | 2003-07-10 | Ultrasonic flowmeter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1151725A JPH1151725A (en) | 1999-02-26 |
| JP3473341B2 true JP3473341B2 (en) | 2003-12-02 |
Family
ID=16607139
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21151197A Expired - Lifetime JP3473341B2 (en) | 1997-08-06 | 1997-08-06 | Ultrasonic flow meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3473341B2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000321106A (en) * | 1999-05-17 | 2000-11-24 | Matsushita Electric Ind Co Ltd | Flow rate measuring apparatus |
| JP4671481B2 (en) * | 2000-09-05 | 2011-04-20 | 愛知時計電機株式会社 | Ultrasonic flow meter |
| JP4830191B2 (en) * | 2000-10-02 | 2011-12-07 | パナソニック株式会社 | Flow measuring device |
| JP4686848B2 (en) * | 2000-11-15 | 2011-05-25 | パナソニック株式会社 | Flow measuring device |
| JP2002148086A (en) * | 2000-11-15 | 2002-05-22 | Matsushita Electric Ind Co Ltd | Flow rate measuring equipment |
| JP5076266B2 (en) * | 2001-09-06 | 2012-11-21 | パナソニック株式会社 | Ultrasonic flow meter |
| JP4661714B2 (en) * | 2006-07-20 | 2011-03-30 | パナソニック株式会社 | Ultrasonic anemometer |
| JP2009008691A (en) * | 2008-10-10 | 2009-01-15 | Panasonic Corp | Flow measuring apparatus |
| JP4888464B2 (en) * | 2008-10-10 | 2012-02-29 | パナソニック株式会社 | Flow measuring device |
| CN104236647A (en) * | 2013-10-30 | 2014-12-24 | 安徽恩米特微电子股份有限公司 | Ultrasonic flowmeter based on single-chip microcomputer |
-
1997
- 1997-08-06 JP JP21151197A patent/JP3473341B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1151725A (en) | 1999-02-26 |
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