JP2006308439A - Flow measuring device of fluid - Google Patents

Flow measuring device of fluid Download PDF

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JP2006308439A
JP2006308439A JP2005131802A JP2005131802A JP2006308439A JP 2006308439 A JP2006308439 A JP 2006308439A JP 2005131802 A JP2005131802 A JP 2005131802A JP 2005131802 A JP2005131802 A JP 2005131802A JP 2006308439 A JP2006308439 A JP 2006308439A
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ultrasonic
wave
received
signal
comparison
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JP4760115B2 (en
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Daisuke Betsusou
大介 別荘
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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<P>PROBLEM TO BE SOLVED: To provide an ultrasonic flow measuring device which improves measurement accuracy by ensuring the detection location of a reception point when a reception waveform amplitude varies. <P>SOLUTION: The device includes a pair of ultrasonic sensors 72 and 73 arranged in the flow path 71 of the fluid, a transmission means 74 for driving the ultrasonic sensors 72 and 73, a comparing means 87 for receiving the signals from the ultrasonic sensors 72 and 73 and detecting the reception by comparing the reception signal with a threshold value, a reception means 75 having a determining means 86 for determining right or wrong of the comparison results of the comparison means 87 and a time counting means 76 for counting the propagation time of ultrasonic wave. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、特に超音波によって流速および/または流量を測定する流体の流れ計測装置に関するものである。   The present invention relates to a fluid flow measuring apparatus that measures flow velocity and / or flow rate by ultrasonic waves in particular.

従来の流体の流れ計測装置の一例としての超音波流量計を図15で示す。図15において、流体管路1の途中に超音波を発信する第1振動子2と受信する第2振動子3とが流れ方向を斜めに横切るごとく配置されている。   FIG. 15 shows an ultrasonic flow meter as an example of a conventional fluid flow measuring device. In FIG. 15, the first vibrator 2 that transmits ultrasonic waves and the second vibrator 3 that receives ultrasonic waves are arranged in the middle of the fluid conduit 1 so as to cross the flow direction obliquely.

4は第1振動子2への発信回路、5は第2振動子3で受信した信号の増幅回路で、この増幅された信号は基準信号と比較回路6で比較され、発信から受信までの時間をタイマカウンタのような計時手段7で求め、その超音波伝幡時間に応じて流体の流速値を、また管路の大きさや流れの状態を考慮して対応する流量値を演算手段8で演算するようにし、この演算手段8の値によって計測間隔変更手段9を介して発信回路4トリガ手段10への信号送出のタイミングを調節するようにしている。   4 is a transmission circuit to the first vibrator 2, and 5 is an amplification circuit for a signal received by the second vibrator 3. This amplified signal is compared with a reference signal by the comparison circuit 6, and the time from transmission to reception is shown. Is calculated by the time counting means 7 such as a timer counter, and the flow rate value of the fluid is calculated according to the ultrasonic propagation time, and the corresponding flow rate value is calculated by the calculation means 8 in consideration of the size of the pipe line and the flow state. The timing of signal transmission to the transmission circuit 4 trigger means 10 is adjusted via the measurement interval changing means 9 according to the value of the calculation means 8.

次にその動作について述べる。トリガ手段10から発信回路4よりバースト信号を送出される。第1振動子2で発信された超音波信号は、流れの中を伝幡して第2振動子3で受信される。増幅回路5と比較回路6で信号処理され、発信から受信までの時間を計時手段7で測定する(例えば、特許文献1参照)。   Next, the operation will be described. A burst signal is transmitted from the transmission circuit 4 from the trigger means 10. The ultrasonic signal transmitted from the first vibrator 2 is transmitted through the flow and received by the second vibrator 3. The signal processing is performed by the amplifier circuit 5 and the comparison circuit 6, and the time from transmission to reception is measured by the time measuring means 7 (see, for example, Patent Document 1).

静止流体中の音をc、流体の流れの速さをvとすると、流れ方向の超音波の伝幡速度は(c+v)となる。振動子5と6の間の距離をL、超音波伝幡軸と管路の中心軸とがなす角度をφとすると、超音波が到達する時間Tは、
T=L/(c+v×cosφ) (1)
となり、(1)式より
v=(L/T−c)/cosφ (2)
となり、Lとφが既知ならTを測定すれば流速vが求められる。この流速より流量Qは、通過面積をS、補正計数をKとすれば、
Q=K×S×v (3)
となる。
If the sound in the static fluid is c and the flow speed of the fluid is v, the propagation speed of the ultrasonic wave in the flow direction is (c + v). When the distance between the transducers 5 and 6 is L, and the angle formed by the ultrasonic transmission axis and the central axis of the pipe is φ, the time T that the ultrasonic wave reaches is:
T = L / (c + v × cos φ) (1)
From the equation (1), v = (L / Tc) / cosφ (2)
If L and φ are known, the flow velocity v can be obtained by measuring T. From this flow velocity, if the flow rate Q is S and the correction count is K,
Q = K × S × v (3)
It becomes.

図16は他の従来例を示すものであり、発信から受信を繰り返し手段11によって繰り返し、設定手段12で設定された回数だけ繰り返しを行う。さらに発振と受信の切換えを切換手段13で行なった後、同様に繰り返しを行う。   FIG. 16 shows another conventional example, in which transmission to reception are repeated by the repeater 11 and repeated for the number of times set by the setting unit 12. Further, after switching between oscillation and reception by the switching means 13, the same is repeated.

すなわち、発振回路4によって第1振動子2から超音波が送信され、この超音波を第2振動子3で受信し、増幅回路5を介し比較回路6に到達すると繰り返し手段11で再びトリガ手段10で発信回路4をトリガする。   That is, an ultrasonic wave is transmitted from the first vibrator 2 by the oscillation circuit 4, and this ultrasonic wave is received by the second vibrator 3 and reaches the comparison circuit 6 via the amplifier circuit 5. To trigger the transmission circuit 4.

この繰り返しは繰り返し設定手段12で設定された回数だけ行われ、設定回数に達すると繰り返しに要した時間を計時手段7で計測する。しかる後、切換手段13により第1振動子2と第2振動子3の発信受信を逆に接続し、今度は第2振動子3から第1振動子2に向かって超音波を発信し前述と同様に到達時間を求め、この差を演算手段8で流速および/または流量値を演算する。   This repetition is performed the number of times set by the repetition setting means 12, and when the set number of times is reached, the time required for the repetition is measured by the time measuring means 7. After that, the transmission and reception of the first vibrator 2 and the second vibrator 3 are reversely connected by the switching means 13, and this time the ultrasonic wave is sent from the second vibrator 3 to the first vibrator 2. Similarly, the arrival time is obtained, and the flow rate and / or flow rate value is calculated by the calculation means 8 using this difference.

静止流体中の音をc、流体の流れの速さをvとすると、流れに対して順方向の超音波の伝幡速度は(c+v)、逆方向の伝幡速度は(c−v)となる。振動子2,3の間の距離をL、超音波伝幡軸と管路の中心軸とがなす角度をφ、繰り返し回数をnとすると、順方向と逆方向のそれぞれの繰り返し時間T1とT2は、
T1=n×L/(c+v×cosφ) (4)
T2=n×L/(c−v×cosφ) (5)
となり、(4)、(5)式より
v=n×L/(2×cosφ)×(1/T1−1/T2) (6)
となり、Lとφが既知ならT1とT2を測定すれば流速vが求められる。しかしながらT1とT2の差は流量が小さくかつ繰り返し回数が小さいときには極めて微小であり、正確に計ることが困難であるので測定回数を多く設定し誤差を比較的小さくし、流量が大きくなるとT1−T2の差も大きくなるので測定が容易になり、その場合には繰り返し設定の回数を小さくしてサンプリング間隔を速くして誤差を小さくする。すなわち、演算手段8によって繰り返し設定手段11の回数を変更する。
If the sound in the static fluid is c and the fluid flow speed is v, the propagation speed of the ultrasonic wave in the forward direction is (c + v) and the propagation speed in the reverse direction is (cv). Become. When the distance between the transducers 2 and 3 is L, the angle formed by the ultrasonic transmission axis and the central axis of the pipe is φ, and the number of repetitions is n, the repetition times T1 and T2 in the forward direction and the reverse direction, respectively. Is
T1 = n × L / (c + v × cos φ) (4)
T2 = n × L / (c−v × cos φ) (5)
From the equations (4) and (5), v = n × L / (2 × cos φ) × (1 / T1-1 / T2) (6)
If L and φ are known, the flow velocity v can be obtained by measuring T1 and T2. However, the difference between T1 and T2 is extremely small when the flow rate is small and the number of repetitions is small, and it is difficult to measure accurately. Therefore, when the number of measurements is set to a large value and the error is relatively small, and the flow rate increases, T1-T2 Since the difference becomes large, the measurement becomes easy. In this case, the number of repeated settings is reduced, the sampling interval is increased, and the error is reduced. That is, the number of repetition setting means 11 is changed by the calculation means 8.

また、超音波を用いて高精度な超音波伝播時間の測定を短時間で、かつ、低消費電力で行う計測方法も提案されている(例えば、特許文献2参照)。   In addition, a measurement method that uses ultrasonic waves to measure ultrasonic propagation time with high accuracy in a short time and with low power consumption has been proposed (see, for example, Patent Document 2).

これは図17に示されるように、超音波信号を流体管路1の内面に対して送受信する振動子2と、前記振動子2の交流受信信号を複数周期にわたって閾値と比較する比較手段6と、振動子2の送信から比較手段6による検出ごとの複数の伝播時間を計測する計時手段7と、計時手段7の計時値の平均値より伝播時間を算出する時間演算手段14とを備えたものである。   As shown in FIG. 17, the vibrator 2 transmits and receives an ultrasonic signal to and from the inner surface of the fluid conduit 1, and the comparison means 6 compares the AC received signal of the vibrator 2 with a threshold over a plurality of periods. And a time measuring means 7 for measuring a plurality of propagation times for each detection by the comparison means 6 from transmission of the vibrator 2, and a time calculating means 14 for calculating the propagation time from the average value of the time measured values of the time measuring means 7. It is.

これによって1回の超音波送受信によって何度も比較手段で比較を行った計測値が得られるので、その平均値を求めることによって高精度な伝播時間の測定値が短時間で得られ、低消費電力で計測を行うことができるように記載されている。   As a result, a measurement value obtained by comparing with the comparison means many times by one ultrasonic transmission / reception can be obtained. Therefore, by obtaining the average value, a highly accurate propagation time measurement value can be obtained in a short time, and the consumption is low. It is described so that measurement can be performed with electric power.

上記図16に示すものは、2つの振動子を用いて、送信と受信とを切り替え、それぞれの受信波形から求められる超音波の伝播時間から流速を求めて、流量を演算する方式である。振動子の受信波形はいくつかの波を持つため、決められた波で伝播時間を求める必要がある。   The method shown in FIG. 16 is a method of calculating the flow rate by using two transducers to switch between transmission and reception, obtaining the flow velocity from the ultrasonic wave propagation time obtained from each received waveform. Since the reception waveform of the vibrator has several waves, it is necessary to obtain the propagation time using a predetermined wave.

例えば、受信波形は図18のようになるので、閾値を超えた第3波が基準値と交わる点P1で、送信からの時間をクロックで計時するようにする。実際の受信波の到達点はPTであるので、PTからP1までの時間は、固定値として扱い、計算時に補正する。   For example, since the received waveform is as shown in FIG. 18, the time from the transmission is measured by the clock at the point P1 where the third wave exceeding the threshold intersects the reference value. Since the actual arrival point of the received wave is PT, the time from PT to P1 is treated as a fixed value and corrected at the time of calculation.

このような方式のため、気体の流れによる受信波形の変化、超音波センサの温度特性、あるいはノイズなどが原因で定められた第3波でない波で伝播時間を検出すると大きな測定誤差となるという課題がある。
特開平8―122117号公報(図1、図7) 特開平10−30947号公報(図1)
Because of this method, there is a problem that if the propagation time is detected by a wave other than the third wave determined due to a change in the received waveform due to the flow of gas, the temperature characteristics of the ultrasonic sensor, or noise, a large measurement error occurs. There is.
JP-A-8-122117 (FIGS. 1 and 7) Japanese Patent Laid-Open No. 10-30947 (FIG. 1)

しかしながら、2つの超音波センサを交互に送信と受信に入れ替えて、それぞれの超音波が伝播する時間を求めて、それらの逆数の差から流速を算出し、さらに流体を通る管路(流路ともいう)の断面積を考慮して流量を求める従来の計測装置は、受信波形が計測精度に大きな影響を与える。この点について図を用いて詳しく説明する。   However, the two ultrasonic sensors are alternately switched to transmission and reception, the time for propagation of each ultrasonic wave is obtained, the flow velocity is calculated from the difference between the reciprocal numbers thereof, and the pipe line (both the flow path is also connected). In the conventional measuring device that obtains the flow rate in consideration of the cross-sectional area of (say), the received waveform greatly affects the measurement accuracy. This point will be described in detail with reference to the drawings.

今、計測システムを図19に示されるような流路50に超音波センサ51,52が配置され、切り替え回路53により超音波センサ51に送信回路54、超音波センサ52に受信回路55が接続され、気体中の超音波の伝播時間T1を測定し、次に、切り替え回路53により超音波センサ52に送信回路54、超音波センサ51に受信回路55が接続され、気体中の超音波の伝播時間T2を測定し、両方の時間差から流速を求めるものとする。   Now, in the measurement system, ultrasonic sensors 51 and 52 are arranged in a flow path 50 as shown in FIG. 19, and a transmission circuit 54 is connected to the ultrasonic sensor 51 and a receiving circuit 55 is connected to the ultrasonic sensor 52 by a switching circuit 53. Then, the propagation time T1 of the ultrasonic wave in the gas is measured, and then the transmission circuit 54 is connected to the ultrasonic sensor 52 and the reception circuit 55 is connected to the ultrasonic sensor 51 by the switching circuit 53, and the propagation time of the ultrasonic wave in the gas T2 is measured, and the flow rate is obtained from the time difference between the two.

図20は超音波センサへの送信信号と、それの受信信号および時間を計測するためのクロック動作を示したタイミングチャートである。   FIG. 20 is a timing chart showing a transmission signal to the ultrasonic sensor, a received signal and a clock operation for measuring the time.

同図(a−1)、(a−2),(a−3)は超音波センサ51が送信側、超音波センサ52が受信側の場合で、同図(b−1)、(b−2)、(b−3)は超音波センサ51が受信側、超音波センサ52が送信側の場合である。   (A-1), (a-2), and (a-3) are the cases where the ultrasonic sensor 51 is on the transmitting side and the ultrasonic sensor 52 is on the receiving side, and (b-1) and (b-) in FIG. 2) and (b-3) are cases where the ultrasonic sensor 51 is on the receiving side and the ultrasonic sensor 52 is on the transmitting side.

気体に図19に示した方向の流れがあるために、超音波の伝播時間T1はT2よりも短くなる。受信波形の検出について図18を用いて詳細に説明する。同図は受信波形を示しており、これの検出は受信波形の第2波と第3波のピーク値のおよそ中間になるように設けられた閾値があり、この閾値を超えた信号があることで、それを受信信号とみなす。   Since the gas has a flow in the direction shown in FIG. 19, the ultrasonic wave propagation time T1 is shorter than T2. The detection of the received waveform will be described in detail with reference to FIG. This figure shows the received waveform, and there is a threshold value that is set to be approximately halfway between the peak values of the second and third waves of the received waveform, and there is a signal that exceeds this threshold value. Therefore, it is regarded as a received signal.

閾値を超えた波形がくると受信波形と判断し、次にこの受信波形が基準値と交わるポイントP1を検出ポイントとする。送信信号から検出ポイントまでのクロックをカウントして超音波の伝播時間を計測する。実際の受信ポイントはPTであるので、PTから第3波までの時間は固定値として扱い、検出ポイントP1までの時間からこの固定値を差し引いて超音波の伝播時間を求める。   When a waveform exceeding the threshold value comes, it is determined as a received waveform, and a point P1 where the received waveform intersects with a reference value is set as a detection point. The propagation time of the ultrasonic wave is measured by counting the clock from the transmission signal to the detection point. Since the actual reception point is PT, the time from PT to the third wave is treated as a fixed value, and the ultrasonic propagation time is obtained by subtracting this fixed value from the time to detection point P1.

超音波センサから放射される超音波は、いくらかの広がりを持っており、超音波が伝播する際に流路を構成する壁面に当たるような場合、受信波形は様々な経路で進入する超音波の合成波となるので、気体の流速により合成波の状態が変化することがある。   The ultrasonic wave radiated from the ultrasonic sensor has some spread, and when the ultrasonic wave propagates, it hits the wall surface that constitutes the flow path, the received waveform is a synthesis of ultrasonic waves that enter through various paths Since it becomes a wave, the state of the synthesized wave may change depending on the flow velocity of the gas.

このような波形の変化があると、設定した固定の閾値では第2波と第3波を区別できなくなり、第3波でない波で伝播時間を検出すると大きな測定誤差となるという課題がある。   When such a waveform change occurs, the second wave and the third wave cannot be distinguished from each other with the set fixed threshold value, and there is a problem that a large measurement error occurs when the propagation time is detected with a wave that is not the third wave.

また、前述したように超音波センサの温度特性、あるいはノイズなどが原因で定められた第3波でない波で伝播時間を検出した場合も大きな測定誤差となるという課題がある。   In addition, as described above, there is a problem that a large measurement error occurs even when the propagation time is detected by a wave other than the third wave determined due to the temperature characteristics of the ultrasonic sensor or noise.

本発明はこのような従来の課題を解決したもので、高精度な計測を可能とした流体の流れ計測装置を提供することを目的とする。   The present invention solves such a conventional problem, and an object of the present invention is to provide a fluid flow measuring device capable of highly accurate measurement.

前記従来の課題を解決するために、本発明の超音波流量計は、流体の通る流路に配置される超音波センサと、前記超音波センサを駆動する送信手段と、前記超音波センサからの信号を受信する受信手段と、超音波の伝播時間を計る計時手段とからなり、前記受信手段は閾値と受信信号を比較して受信を検知する比較手段と、前記比較手段の比較結果の妥当性を判断する判断手段を備えることで、大きな計測誤差の発生を解消できる。   In order to solve the conventional problem, an ultrasonic flowmeter of the present invention includes an ultrasonic sensor disposed in a flow path through which fluid flows, a transmission unit that drives the ultrasonic sensor, and an ultrasonic sensor from the ultrasonic sensor. The receiving means comprises a receiving means for receiving a signal and a time measuring means for measuring the propagation time of the ultrasonic wave. The receiving means compares the threshold value with the received signal to detect reception, and the validity of the comparison result of the comparing means. The generation of a large measurement error can be eliminated by providing the determination means for determining.

本発明の超音波流量計は、超音波の受信波形が流速、温度の影響で変化しても適確に受信波を検知して、その正誤を判断することで、計測の精度を向上することができるという効果がある。   The ultrasonic flowmeter of the present invention improves the accuracy of measurement by accurately detecting the received wave even if the received waveform of the ultrasonic wave changes due to the influence of flow velocity and temperature, and judging whether the wave is correct. There is an effect that can be.

第1の発明は、流体の通る流路に配置される超音波センサと、前記超音波センサを駆動する送信手段と、前記超音波センサからの信号を受信する受信手段と、超音波の伝播時間を計る計時手段とからなり、前記受信手段は閾値と受信信号を比較して受信を検知する比較手段と、前記比較手段の比較結果の正誤を判断する判断手段を備える。   According to a first aspect of the present invention, there is provided an ultrasonic sensor disposed in a flow path through which a fluid passes, a transmission unit that drives the ultrasonic sensor, a reception unit that receives a signal from the ultrasonic sensor, and an ultrasonic propagation time. The receiving means includes a comparing means for detecting reception by comparing a threshold value with a received signal, and a judging means for judging whether the comparison result of the comparing means is correct.

超音波センサの受信波形は、振動子振動に継続性があるため、送信信号を1波だけ与えても複数周期の波形となる。また、受信波形は徐々に波形ピーク値が上昇して、その後減少するようなエンベロープを持つ。このため受信波形の検知を比較手段で行う場合は、比較手段の閾値をどのようなレベルに設定するかで、受信の何波目を検知するかが決まる。しかしながら、受信波形のエンベロープは温度・流速で変化するため、設定した閾値で検知する波は何波目であるかを限定することが困難である。   Since the reception waveform of the ultrasonic sensor has continuity in vibrator vibration, even if only one transmission signal is given, it becomes a waveform of a plurality of cycles. The received waveform has an envelope in which the waveform peak value gradually increases and then decreases. For this reason, when the reception waveform is detected by the comparison means, what level of reception wave is detected depends on what level the threshold value of the comparison means is set. However, since the envelope of the received waveform varies with temperature and flow velocity, it is difficult to limit the number of waves detected with the set threshold.

従って、例えば流量が無い場合において、3波目で検知するように閾値を設定しても大流量になると、この閾値では4波目で検知することが起り得る。1波ずれると伝播時間計測が1周期に相当する時間だけ増減するので、大きな測定誤差となる。   Therefore, for example, when there is no flow rate, even if a threshold value is set so that detection is performed at the third wave, if the flow rate is large, detection at the fourth wave may occur at this threshold value. When one wave is shifted, the propagation time measurement is increased or decreased by a time corresponding to one period, resulting in a large measurement error.

そこで、閾値を受信信号の基準値に極めて近い値に設定する。ここで基準値とは、交流信号である超音波センサの受信信号を回路で信号処理ができるように、直流分を重畳させて、受信信号を正、または負のいずれかになるようにした場合の直流分を示す。   Therefore, the threshold value is set to a value very close to the reference value of the received signal. Here, the reference value is the case where the received signal is either positive or negative by superimposing the DC component so that the circuit can process the received signal of the ultrasonic sensor, which is an AC signal. The direct current component is shown.

このように、閾値を基準値に極めて近い値にすることで受信した場合の波形変化を、即検知することができるようになり、受信の1波目を検知しやすくなる。受信の1波目の波高値も温度・流速により変化するが、閾値はこの波高値の変化範囲の最小値よりも低い値に設定されることで、確実に1波目をとらえることができる。   In this way, by setting the threshold value to a value very close to the reference value, it becomes possible to immediately detect a waveform change when received, and it becomes easier to detect the first wave of reception. The peak value of the first received wave also changes depending on the temperature and flow velocity, but the threshold value is set to a value lower than the minimum value of the change range of the peak value, so that the first wave can be reliably captured.

しかしながら、閾値は基準値に近い値に設定されるため、ノイズが重畳した基準値で、比較手段が動作し誤った信号を出力することが起りやすくなる。   However, since the threshold is set to a value close to the reference value, it is easy for the comparator to operate and output an erroneous signal at the reference value on which noise is superimposed.

そこで、比較手段からの出力信号の正誤を判断する判断手段を設けることで、誤った信号での計測を行わないようにすることができる。   Therefore, by providing a determination unit that determines whether the output signal from the comparison unit is correct or incorrect, it is possible to prevent measurement using an incorrect signal.

第2の発明は、特に、第1の発明の比較手段は、基準値に対して、2つの閾値で受信波形との比較を行い、判断手段は、比較手段の結果が2つの閾値のどちらから先に検知したかを判断するようにする。   In the second invention, in particular, the comparison means of the first invention compares the received waveform with the two threshold values with respect to the reference value, and the judgment means determines whether the result of the comparison means is from which of the two threshold values. Judge whether it was detected first.

例えば、基準値に対して正負の2つの閾値を設けると、正しい信号を検知した場合は必ず先に比較される閾値と後から検知される閾値とが決まっているので、これとは異なる順番で検知された信号は誤ったものと判断することができる。   For example, if two threshold values, positive and negative, are provided with respect to the reference value, a threshold value to be compared first and a threshold value to be detected later are always determined when a correct signal is detected. It can be determined that the detected signal is incorrect.

第3の発明は、特に、第2の発明において、2つの閾値の1つで比較されてから、もう一つの閾値で比較されるまでの時間を計時することで、比較手段の信号の正誤を判断手段で判断するようにする。例えば、基準値に対して正負に設けられた2つの閾値において、正しい信号を検知した場合は必ず先に比較される閾値と後から検知される閾値との時間間隔がある範囲内で決まっているので、この時間間隔を計時することで、比較手段の出力信号の正誤を判断することができる。   In particular, in the third invention, in the second invention, the time from the comparison at one of the two thresholds to the comparison at the other threshold is counted, thereby correcting the correctness of the signal of the comparison means. Judgment is made by the judging means. For example, in two threshold values provided positive and negative with respect to the reference value, when a correct signal is detected, the time interval between the threshold value to be compared first and the threshold value to be detected later is determined within a certain range. Therefore, by measuring this time interval, it is possible to determine whether the output signal of the comparison means is correct or incorrect.

第4の発明は、特に、第2の発明において、閾値を切換え複数の閾値で比較できるようにした比較手段を備えたることにより、回路の素子数を節約することができる。   In particular, the fourth invention can save the number of circuit elements by providing a comparison means in which the threshold value can be switched and compared by a plurality of threshold values in the second invention.

第5の発明は、特に、第1の発明において、流体の通る流路に配置される複数の超音波センサを備え、一方の超音波センサから他方の超音波センサへ送信した時の超音波の伝播時間T1と、逆向きに送信した時の超音波の伝播時間T2とから流速および/または流量を求めるものにおいて、受信波の波数をカウントして、波数の比較で受信波の正誤を判断する判断手段を備える。   In particular, the fifth invention includes a plurality of ultrasonic sensors arranged in the flow path through which the fluid passes in the first invention, and the ultrasonic wave when transmitted from one ultrasonic sensor to the other ultrasonic sensor is provided. In obtaining the flow velocity and / or flow rate from the propagation time T1 and the propagation time T2 of the ultrasonic wave when transmitted in the opposite direction, the wave number of the received wave is counted and the correctness of the received wave is judged by comparing the wave number. Judgment means is provided.

これにより、一方の超音波センサから他方の超音波センサへ送信した時の波数と、逆向きに送信した時の波数が異なれば、比較手段の比較結果は誤りであることが判断できる。   Thus, if the wave number when transmitted from one ultrasonic sensor to the other ultrasonic sensor is different from the wave number when transmitted in the opposite direction, it can be determined that the comparison result of the comparison means is incorrect.

第6の発明は、特に、第5の発明において、ピークホールド回路を用いた判断手段とする。これにより、ピーク値の更新回数で波数を求めるようにすることができる。   The sixth aspect of the invention is particularly the determination means using the peak hold circuit in the fifth aspect of the invention. As a result, the wave number can be obtained from the number of updates of the peak value.

第7の発明は、特に、第6の発明において、ピークホールド回路と比較手段を有した判断手段とする。前記ピークホールド回路出力と受信波とを比較して、波数を求めるためのパルス信号を形成することができる。   In particular, the seventh invention is a judging means having a peak hold circuit and a comparing means in the sixth invention. By comparing the peak hold circuit output and the received wave, a pulse signal for obtaining the wave number can be formed.

第8の発明は、特に、第7の発明において、計時手段を有し、波数を求めるために形成されたパルス間隔の時間を計時することで、形成されたパルス信号の正誤を判断手段で判断できるようになる。   In an eighth aspect of the invention, in particular, in the seventh aspect of the invention, the time measuring means is provided, and the time of the pulse interval formed for obtaining the wave number is timed, so that the correctness of the formed pulse signal is determined by the determining means. become able to.

(実施の形態1)
以下、本発明の実施の形態1について図面を参照して説明する。なお、この実施の形態において本発明が限定されるものではない。
(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to this embodiment.

図1において、気体が流れる流路71に超音波センサ72,73とが配置される。超音波センサ72,73には、送信手段74から送信信号が送られる。また、超音波センサの受信信号は受信手段75に伝えられる。   In FIG. 1, ultrasonic sensors 72 and 73 are disposed in a flow path 71 through which gas flows. A transmission signal is sent from the transmission means 74 to the ultrasonic sensors 72 and 73. Further, the reception signal of the ultrasonic sensor is transmitted to the receiving means 75.

送信と受信は切換手段77で選択される。一方の超音波センサ72が送信手段74に接続するように選択された場合は、他方の超音波センサ73は受信手段75に接続するように選択される。   Transmission and reception are selected by the switching means 77. When one ultrasonic sensor 72 is selected to connect to the transmission means 74, the other ultrasonic sensor 73 is selected to connect to the reception means 75.

今、同図に示されるように気体の流れが左から右方向の場合、超音波センサ72が送信した超音波は伝播時間T1後に超音波センサ73に到達する。反対に超音波センサ73が送信した超音波は伝播時間T2後に超音波センサ72に到達するが、気体の流れの方向から、T1<T2となる。これらの伝播時間T1、T2は計時手段76によって計時される。   If the gas flow is from left to right as shown in the figure, the ultrasonic wave transmitted by the ultrasonic sensor 72 reaches the ultrasonic sensor 73 after the propagation time T1. On the contrary, the ultrasonic wave transmitted by the ultrasonic sensor 73 reaches the ultrasonic sensor 72 after the propagation time T2, but T1 <T2 from the gas flow direction. These propagation times T1 and T2 are timed by the time measuring means 76.

演算手段79は計時手段76からのデータを基にして流量を求める。   The calculating means 79 obtains the flow rate based on the data from the time measuring means 76.

以上が超音波計測装置78の主要部である。   The above is the main part of the ultrasonic measuring device 78.

図2は、超音波センサの送信(送信手段)波形と、受信(受信手段)波形とクロック(計時手段)波形を示し、同図(a-1)、(a-2)、(a−3)は、それぞれ超音波センサ72から送信して超音波センサ73で受信する場合である。   FIG. 2 shows a transmission (transmission means) waveform, a reception (reception means) waveform, and a clock (time measurement means) waveform of the ultrasonic sensor, and (a-1), (a-2), and (a-3) in FIG. ) Is a case where each is transmitted from the ultrasonic sensor 72 and received by the ultrasonic sensor 73.

同図(a−1)によれば送信信号は3波となっており、受信波形は同図(a−2)のような波形となる。超音波の伝播時間T1は、受信波形が基準値と交わる点であるTA1からTA7の時間を同図(a−3)のクロックでカウントして、あらかじめ定めた規定値T0を引くことで補正して求められる。同図(b-1)、(b-2)、(b−3)は、それぞれ超音波センサ73から送信して超音波センサ72で受信する場合で、同様にして超音波の伝播時間T2が求められる。   According to (a-1) in the figure, the transmission signal has three waves, and the reception waveform is as shown in (a-2) in the figure. The ultrasonic wave propagation time T1 is corrected by counting the time from TA1 to TA7, which is the point where the received waveform intersects the reference value, with the clock in FIG. Is required. (B-1), (b-2), and (b-3) in the figure are cases where the ultrasonic wave is transmitted from the ultrasonic sensor 73 and received by the ultrasonic sensor 72, and the ultrasonic propagation time T2 is similarly determined. Desired.

同図に示される閾値は受信波を検知するために、設けられるもので受信手段の比較手段への入力信号となるものである。比較手段を用いて受信を検知すると、さらに別の比較手段を用いて、基準値と交差する点、TA1からTA7および、TB1からTB7を検知するようにしている。   The threshold shown in the figure is provided to detect a received wave and serves as an input signal to the comparing means of the receiving means. When reception is detected using the comparison means, further comparison means are used to detect points intersecting the reference values, TA1 to TA7 and TB1 to TB7.

次に図3を用いて受信手段について説明する。超音波センサ72,73の受信信号は切換手段77を介して、受信手段75の増幅手段80に入力される。増幅された信号は、増幅手段81でさらに増幅され、比較手段83,84に入力される。   Next, the receiving means will be described with reference to FIG. The reception signals of the ultrasonic sensors 72 and 73 are input to the amplification means 80 of the reception means 75 via the switching means 77. The amplified signal is further amplified by the amplification means 81 and input to the comparison means 83 and 84.

基準値設定部85は基準値を与える。これは、交流の受信信号に重畳されるとともに、比較手段87へも入力される。比較手段83、84の信号は判断手段86に入力される。比較手段83,84で受信を検知し、その受信の正誤を判断手段86で判断する。   The reference value setting unit 85 gives a reference value. This is superimposed on the AC reception signal and also input to the comparison means 87. The signals from the comparison means 83 and 84 are input to the determination means 86. The comparison means 83 and 84 detect the reception, and the determination means 86 determines whether the reception is correct or incorrect.

判断が正であれば、基準値が与えられている比較手段87で受信波と基準値を比較して、交わるポイント(図2のTA1からTA7および、TB1からTB7)を検知する。比較手段87の信号は、計時手段76に伝達され、伝播時間が算定される。   If the determination is positive, the comparison means 87 to which the reference value is given compares the received wave with the reference value, and detects intersecting points (TA1 to TA7 and TB1 to TB7 in FIG. 2). The signal of the comparison means 87 is transmitted to the time measuring means 76, and the propagation time is calculated.

図4は超音波センサ72から送信して、超音波センサ73で受信した場合の、比較手段の入力信号と出力信号の波形を示し、同図(a)は入力信号で、比較手段83の閾値Aと、比較手段84の閾値Bとを合わせて記載している。同図(b)は比較手段83の出力信号、同図(c)は比較手段84の出力信号である。   FIG. 4 shows the waveforms of the input signal and output signal of the comparison means when transmitted from the ultrasonic sensor 72 and received by the ultrasonic sensor 73. FIG. 4A shows the input signal and the threshold value of the comparison means 83. A and the threshold value B of the comparison means 84 are described together. FIG. 4B shows the output signal of the comparison means 83, and FIG.

正常な動作では、比較手段83の出力信号から先にHIになり、後から比較手段84の出力信号がHIとなる。また、比較手段83の出力信号と、比較手段84の出力信号が同時にHIになることはない。このような判断は判断手段が行い受信の正誤を判断する。受信が正しいと判断されれば、比較手段87で基準値との交差点TA1からTA7を検知して、送信からの伝播時間を求める。   In normal operation, the output signal of the comparison means 83 first becomes HI, and the output signal of the comparison means 84 becomes HI later. Further, the output signal of the comparison unit 83 and the output signal of the comparison unit 84 do not become HI at the same time. Such a determination is made by the determination means to determine whether the reception is correct. If it is determined that the reception is correct, the comparison unit 87 detects the intersections TA1 to TA7 with the reference value, and obtains the propagation time from the transmission.

図5は同じく超音波センサ72から送信して、超音波センサ73で受信した場合の比較手段の入力信号と出力信号の波形を示し、同図(a)は受信信号である入力信号で、第1波目にノイズなどが重畳して、閾値Aを超えずに同図(b)の比較手段83の出力がHIにならない状態から、先に同図(c)の比較手段84の出力がHIになった状態を示したものである。この場合、判断手段は受信信号が誤っていると判断して、伝播時間の算出は行わず計測をやり直す。   FIG. 5 shows the waveforms of the input signal and output signal of the comparison means when similarly transmitted from the ultrasonic sensor 72 and received by the ultrasonic sensor 73. FIG. 5 (a) shows the input signal which is the received signal. From the state in which noise or the like is superimposed on the first wave and the output of the comparison means 83 in FIG. 7B does not become HI without exceeding the threshold A, the output of the comparison means 84 in FIG. It shows the state that became. In this case, the determination means determines that the received signal is incorrect, and performs measurement again without calculating the propagation time.

図6は同じく超音波センサ72から送信して、超音波センサ73で受信した場合の比較手段の入力信号と出力信号の波形を示し、同図(a)は受信信号である入力信号、同図(b)は比較手段83の出力、同図(c)は比較手段84の出力、同図(d)は比較手段87の出力を表している。   FIG. 6 shows the waveforms of the input signal and the output signal of the comparison means when similarly transmitted from the ultrasonic sensor 72 and received by the ultrasonic sensor 73. FIG. 6A shows the input signal as the received signal. (B) shows the output of the comparison means 83, (c) shows the output of the comparison means 84, and (d) shows the output of the comparison means 87.

正常に受信を検知した場合は、比較手段87は必ず、比較手段83,84の出力がLOWのときHIに立ち上がり、同様に比較手段A83,84の出力がLOWのときLOWに下がる。判断手段はこのような論理が成り立っているかを判断することで、受信信号の正誤を判断することができる。   When reception is normally detected, the comparison means 87 always rises to HI when the outputs of the comparison means 83 and 84 are LOW, and similarly falls to LOW when the outputs of the comparison means A 83 and 84 are LOW. The determination means can determine whether the received signal is correct or not by determining whether such logic is established.

図7(a)は同じく超音波センサ72から送信して、超音波センサ73で受信した場合の比較手段の入力信号と出力信号の波形を示し、同図(a)は受信信号である入力信号、同図(b)は比較手段83の出力、同図(c)は比較手段84の出力、同図(d)はクロックを表している。   FIG. 7A shows the waveforms of the input signal and output signal of the comparison means when similarly transmitted from the ultrasonic sensor 72 and received by the ultrasonic sensor 73, and FIG. 7A shows the input signal which is the received signal. 4B shows the output of the comparison means 83, FIG. 4C shows the output of the comparison means 84, and FIG. 4D shows the clock.

クロックは、比較手段83の出力の立ち上がりから、比較手段84の出力の立ち上がりまで動作する。判断手段はクロック数をカウントして、その動作時間を求めることで、比較手段83,84の出力信号の正誤を判断する。   The clock operates from the rise of the output of the comparison unit 83 to the rise of the output of the comparison unit 84. The judging means counts the number of clocks and obtains the operating time thereof, thereby judging whether the output signals of the comparing means 83 and 84 are correct.

図8は同じく比較手段の入力信号と出力信号の波形を示し、同図(a)の受信波形(入力信号)は図7(a)に比べてその振幅が小さくなっている。図8(b)は比較手段83の出力、同図(c)は比較手段Bの出力、同図(d)はクロックを表している。クロックは、比較手段83の出力の立ち上がりから、比較手段84の出力の立ち上がりまで動作しているが、図7(d)の場合に比べ、クロック数が少なくなっている。   FIG. 8 shows the waveforms of the input signal and output signal of the comparison means, and the amplitude of the received waveform (input signal) in FIG. 8 (a) is smaller than that in FIG. 7 (a). 8B shows the output of the comparison means 83, FIG. 8C shows the output of the comparison means B, and FIG. 8D shows the clock. The clock operates from the rise of the output of the comparison means 83 to the rise of the output of the comparison means 84, but the number of clocks is smaller than in the case of FIG.

このように受信波形によってクロック数(動作時間)は異なるが、正常な場合動作時間は、ほぼ受信波の1/4周期から1/2周期の中に入るので、判断手段はこの時間外であるものを誤った受信波形であると判断する。   As described above, the number of clocks (operation time) varies depending on the reception waveform, but in normal cases, the operation time falls within the period from ¼ period to ½ period of the reception wave. It is determined that the received waveform is incorrect.

図9は受信波形の正誤を判断する他の構成を示し、図3で示される回路ブロック図と共通する部分は同じ符号を用いており、詳細な説明は図3のものを援用する。増幅手段81からの増幅された受信信号をピークホールド回路88で受け、ピーク値が更新される回数を判断手段86がカウントする。   FIG. 9 shows another configuration for judging whether the received waveform is correct or not. The parts common to the circuit block diagram shown in FIG. 3 are denoted by the same reference numerals, and the detailed description of FIG. The amplified received signal from the amplifying means 81 is received by the peak hold circuit 88, and the judging means 86 counts the number of times the peak value is updated.

また、増幅手段81からの増幅された受信信号は、比較手段87にも入力される。この比較手段87は受信波と基準値との比較結果を出力する。   The amplified received signal from the amplifying unit 81 is also input to the comparing unit 87. The comparison means 87 outputs a comparison result between the received wave and the reference value.

図9で示された回路ブロック図の各部波形を図10に示す。同図(a)は増幅手段81からの増幅された受信信号であり、ピークホールド回路88の入力信号となる信号である。この受信信号は、超音波センサ72から送信され、超音波センサ73で受信した場合の波形である。   FIG. 10 shows waveforms of respective parts of the circuit block diagram shown in FIG. FIG. 5A shows an amplified received signal from the amplifying unit 81 and a signal that becomes an input signal of the peak hold circuit 88. This reception signal is a waveform when transmitted from the ultrasonic sensor 72 and received by the ultrasonic sensor 73.

同図(b)はピークホールド回路88の出力信号であり、入力信号である受信波形のピーク毎にピーク値が更新されている様子を示している。また、同図(c)は判断手段86の内部信号で、ピークホールド回路88の信号を受けて、ピーク値が更新される毎にパルスを発生する回路部の信号波形である。   FIG. 5B shows an output signal of the peak hold circuit 88, and shows how the peak value is updated for each peak of the received waveform that is the input signal. FIG. 6C shows an internal signal of the determination means 86, which is a signal waveform of a circuit unit that receives a signal of the peak hold circuit 88 and generates a pulse every time the peak value is updated.

判断手段86はこのパルスにより、ピーク値の更新回数を記憶する。この場合は更新回数が4回である。同図(a)の増幅手段81からの増幅された受信信号は、比較手段87の入力信号でもある。比較手段87によって、基準値と受信信号との比較が行われ、その出力が計時手段76に入力される。   The judging means 86 stores the number of updates of the peak value by this pulse. In this case, the number of updates is four. The amplified received signal from the amplifying means 81 shown in FIG. The comparison unit 87 compares the reference value with the received signal, and the output is input to the time measuring unit 76.

ただし、比較手段87の動作は同図(c)の判断手段内部信号Aの1つ目のパルスが出力されてから行われる。計時手段76は図に示される基準値と受信信号との交差するポイントTA1からTA7の時間を求める。求められた時間TA1からTA7はいったん記憶される。   However, the operation of the comparison means 87 is performed after the first pulse of the determination means internal signal A in FIG. The time measuring means 76 obtains the time from points TA1 to TA7 at which the reference value shown in FIG. The obtained times TA1 to TA7 are temporarily stored.

次に、超音波センサ73から送信され、超音波センサ72で受信する動作に移る。図は図10と同等なものになるので図は省略するが、同様に計時手段76が求める基準値と受信信号との交差するポイントの時間をTB1からTB7とする。式(6)で示されるように時間の逆数差から伝播時間を求める場合は、例えばTA1とTB1の一対のデータから伝播時間をもとめ、同様に、TA2とTB2、TA3とTB3のようなそれぞれ一対のデータから求める。   Next, the operation is transmitted from the ultrasonic sensor 73 and received by the ultrasonic sensor 72. Since the figure is equivalent to that in FIG. 10, the figure is omitted, but similarly, the time at the point where the reference value obtained by the time measuring means 76 intersects the received signal is defined as TB1 to TB7. When the propagation time is obtained from the reciprocal difference of time as shown in Expression (6), for example, the propagation time is obtained from a pair of data of TA1 and TB1, and similarly, a pair such as TA2 and TB2, TA3 and TB3, respectively. Obtain from the data.

ただし、TA2とTB2は2波目の伝播時間であるので、計算する場合はこのことを考慮しておく。また、TA3とTB3は3波目であることを同様に考慮しておく。このようにして伝播時間を求めると、7つのデータが得られるので、この7つのデータを平均すれば、超音波センサ72および超音波センサ73においてそれぞれ1回の送受信で、従来例のように一つの一対の伝播時間データから流速を求める場合に比べ、よりばらつきの少ない計測データを得ることができる。   However, since TA2 and TB2 are propagation times of the second wave, this is taken into consideration when calculating. Similarly, consider that TA3 and TB3 are the third wave. If the propagation time is obtained in this way, seven data are obtained. If these seven data are averaged, the ultrasonic sensor 72 and the ultrasonic sensor 73 each transmit and receive one time as in the conventional example. Compared with the case where the flow velocity is obtained from a pair of propagation time data, measurement data with less variation can be obtained.

図11は図10と同様な各部波形を示しているが、同図(a)の受信信号は超音波センサ73から送信され、超音波センサ72で受信した場合の波形である。流速の関係で、受信波形のピーク値は図10に比べて低くなっているが、ピークに達すまでの波数は変わらない(波数がかわるのは、温度変化で超音波センサの特性変化があるときに生じるが、この場合も超音波センサ72から送信して超音波センサ73で受信する場合と、その反対の場合とで、受信波形がピークに達するまでの波数は同じである)。   FIG. 11 shows the waveform of each part similar to FIG. 10, but the received signal in FIG. 11A is a waveform when transmitted from the ultrasonic sensor 73 and received by the ultrasonic sensor 72. The peak value of the received waveform is lower than that in FIG. 10 because of the flow velocity, but the wave number until the peak is reached does not change (the wave number changes when there is a change in the characteristics of the ultrasonic sensor due to temperature change). However, also in this case, the wave number until the received waveform reaches the peak is the same in the case where it is transmitted from the ultrasonic sensor 72 and received by the ultrasonic sensor 73 and the opposite case).

このため、ピークホールド回路では同図(b)に示されるように、受信波形の1波目をとらえることかできずに、2波目からとらえている。従って、判断手段の内部信号も受信波の2波目から出力されているので、比較手段87は、基準値と受信信号との交差するポイントTB2からTB7の時間を求めることになる。   For this reason, the peak hold circuit cannot capture the first wave of the received waveform as shown in FIG. Accordingly, since the internal signal of the judging means is also output from the second wave of the received wave, the comparing means 87 obtains the time from TB2 to TB7 where the reference value and the received signal intersect.

この場合のピーク値の更新回数は3回で、図10(c)に比べ、更新回数が1回少ないので判断手段86は、TB1が検知できなかったものと判断し、これらのデータは適用せずに最初から計測をやり直すか、または、TA2とTB2の一対のデータから以降を適用する。   In this case, the number of updates of the peak value is 3, and the number of updates is one less than in FIG. 10C. Therefore, the determination unit 86 determines that TB1 could not be detected, and these data are not applied. The measurement is started again from the beginning, or the following is applied from a pair of data of TA2 and TB2.

図12も同様に図9で示された回路ブロック図の各部波形を示している。同図(a)は超音波センサ72の送信信号、同図(b)は超音波センサ73の受信信号、(c)はピークホールド回路出力信号、(d)は断手段内部信号A、(e)はクロックを表している。   Similarly, FIG. 12 shows waveforms of respective parts of the circuit block diagram shown in FIG. (A) is a transmission signal of the ultrasonic sensor 72, (b) is a reception signal of the ultrasonic sensor 73, (c) is a peak hold circuit output signal, (d) is a cutting means internal signal A, (e ) Represents a clock.

同図(b)において、特に送信から受信の間にノイズが重畳されている様子を表している。同図(c)のピークホールド回路出力は、ノイズを検知している様子を表している。同図(d)は、ピークホールド回路出力に応じて、電圧変化があったタイミングでパルスを出力している。ノイズを検知しているので、同図(e)のクロックで計時される同図(e)のパルス間隔は一定周期の無いものとなる。   FIG. 2B shows a state in which noise is superimposed particularly between transmission and reception. The peak hold circuit output in FIG. 6 (c) represents a state where noise is detected. FIG. 6D shows a pulse output at a timing when there is a voltage change according to the peak hold circuit output. Since noise is detected, the pulse interval shown in FIG. 4E measured by the clock shown in FIG. 3E has no fixed period.

このパルスに送信信号に近い周期が見出されない場合は、ピークホールド回路出力をリセットしている。また、正しい受信信号が検知されている部分では、パルス間隔は一定周期を持つ。   If a period close to the transmission signal is not found in this pulse, the peak hold circuit output is reset. Further, the pulse interval has a certain period in the portion where the correct received signal is detected.

このように、クロックを用いてパルス周期を計時することで、受信信号の正しい信号とノイズとを見分けることができる。一定周期を持ったパルスの数で、受信信号がピークに達するまでの波数を知ることができる。   Thus, by measuring the pulse period using the clock, it is possible to distinguish the correct signal from the received signal from noise. It is possible to know the wave number until the received signal reaches the peak by the number of pulses having a certain period.

(実施の形態2)
図13において、ピークホールド回路88と比較手段89を有する。この比較手段89は、ピークホールド回路88の出力と、増幅手段81からの信号である受信波信号とを比較することで、受信波の波数を数えるためのパルス信号を出力する。
(Embodiment 2)
In FIG. 13, a peak hold circuit 88 and comparison means 89 are provided. The comparing unit 89 compares the output of the peak hold circuit 88 with the received wave signal that is a signal from the amplifying unit 81, and outputs a pulse signal for counting the wave number of the received wave.

図14は図13で示される回路ブロック図の一部の波形を示した波形図である。(a)受信波信号(比較手段D入力信号)と(b)ピークホールド回路出力信号(比較手段D入力信号)とを比較手段Dで比較して得られた信号が(c)の波数を求めるためのパルス信号{比較手段D出力信号(判断手段内部信号)}となる。   FIG. 14 is a waveform diagram showing a partial waveform of the circuit block diagram shown in FIG. The signal obtained by comparing (a) the received wave signal (comparison means D input signal) and (b) the peak hold circuit output signal (comparison means D input signal) by the comparison means D determines the wave number of (c). Pulse signal {comparison means D output signal (determination means internal signal)}.

図では受信波のピークから次の一つの波まで検知するように、(a)と(b)の信号レベルを調整している。   In the figure, the signal levels of (a) and (b) are adjusted so as to detect from the peak of the received wave to the next one wave.

(c)の波数を求めるためのパルス信号の立ち上がりの間隔は、ほぼ受信波の周期に近い値であるので、これを(d)のクロックを用いて確認し、受信波の正誤を判断する。受信波の波数は(b)パルス信号をカウントすることで得ることができる。   Since the rising interval of the pulse signal for obtaining the wave number of (c) is a value that is substantially close to the period of the received wave, this is confirmed using the clock of (d) and the correctness of the received wave is judged. The wave number of the received wave can be obtained by counting (b) pulse signals.

以上のように、本発明にかかる超音波流量計は、超音波センサの受信波形の振幅変化によらず適確な超音波の伝播時間測定が行え、かつ、1回の受信波形から複数の伝播時間データを取得でき、平均化をすることができるので計測精度が向上させることができ、かつ、超音波の受信波形が変化しやすい扁平流路を用いることも可能であるので、広い流量領域にわたり正確な計測が要求される、天然ガスや液化石油ガスの流量を測定する業務用や家庭用の超音波式ガス流量測定装置(ガスメータ)の用途に展開できる。   As described above, the ultrasonic flowmeter according to the present invention can accurately measure the propagation time of ultrasonic waves regardless of the amplitude change of the received waveform of the ultrasonic sensor, and can perform a plurality of propagations from a single received waveform. Since time data can be acquired and averaged, measurement accuracy can be improved, and it is also possible to use a flat flow path that easily changes the received waveform of the ultrasonic wave. It can be used for commercial and household ultrasonic gas flow measurement devices (gas meters) that measure the flow rate of natural gas and liquefied petroleum gas, which require accurate measurement.

本発明の実施の形態1の超音波流れ測定装置の構成を示すブロック図The block diagram which shows the structure of the ultrasonic flow measuring apparatus of Embodiment 1 of this invention. 同の超音波流れ測定装置の波形図Waveform diagram of the same ultrasonic flow measuring device 同超音波流れ測定装置における受信手段の回路ブロック図Circuit block diagram of receiving means in the ultrasonic flow measuring device 同超音波流れ測定装置の波形図Waveform diagram of the ultrasonic flow measurement device 同超音波流れ測定装置の波形図Waveform diagram of the ultrasonic flow measurement device 同同超音波流れ測定装置の波形図Waveform diagram of the same ultrasonic flow measuring device 同同超音波流れ測定装置の波形図Waveform diagram of the same ultrasonic flow measuring device 同同超音波流れ測定装置の波形図Waveform diagram of the same ultrasonic flow measuring device 本発明の実施の形態2の同超音波流れ測定装置における受信手段の回路ブロック図Circuit block diagram of receiving means in the ultrasonic flow measuring apparatus according to Embodiment 2 of the present invention 同同超音波流れ測定装置の受信手段の波形図Waveform diagram of receiving means of the same ultrasonic flow measuring device 同同超音波流れ測定装置の受信手段の波形図Waveform diagram of receiving means of the same ultrasonic flow measuring device 同同超音波流れ測定装置の受信手段の波形図Waveform diagram of receiving means of the same ultrasonic flow measuring device 同同超音波流れ測定装置の受信手段の回路ブロック図Circuit block diagram of receiving means of the same ultrasonic flow measuring device 同同超音波流れ測定装置の受信手段の波形図Waveform diagram of receiving means of the same ultrasonic flow measuring device 従来の同超音波流れ測定装置の構成を示す制御ブロック図Control block diagram showing the configuration of the conventional ultrasonic flow measuring device 従来の他の同超音波流れ測定装置の構成を示す制御ブロック図Control block diagram showing the configuration of another conventional ultrasonic flow measuring device 従来の他の同超音波流れ測定装置の構成を示す制御ブロック図Control block diagram showing the configuration of another conventional ultrasonic flow measuring device 従来の同超音波流れ測定装置の超音波センサの受信信号波形図Received signal waveform diagram of ultrasonic sensor of conventional ultrasonic flow measuring device 従来の同超音波流れ測定装置の構成を示すブロック図Block diagram showing the configuration of the conventional ultrasonic flow measuring device 従来の同超音波流れ測定装置の波形図Waveform diagram of the conventional ultrasonic flow measurement device

符号の説明Explanation of symbols

71 流路
72,73 超音波センサ
74 送信手段
75 受信手段
76 計時手段
86 判断手段
87 比較手段
88 ピークホールド回路
89 比較手段
71 Flow path 72, 73 Ultrasonic sensor 74 Transmission means 75 Reception means 76 Timekeeping means 86 Judgment means 87 Comparison means 88 Peak hold circuit 89 Comparison means

Claims (8)

流体の通る流路に配置された一対の超音波センサと、前記超音波センサを駆動する送信手段と、前記超音波センサからの信号を受信するとともに、閾値と受信信号を比較して受信を検知する比較手段、および前記比較手段の比較結果の正誤を判断する判断手段を有する受信手段と、超音波の伝播時間を計る計時手段とを具備した流体の流れ計測装置。 A pair of ultrasonic sensors arranged in the flow path through which the fluid passes, transmission means for driving the ultrasonic sensors, and signals from the ultrasonic sensors are received, and reception is detected by comparing the threshold and the received signal. And a receiving means having a judging means for judging whether the comparison result of the comparing means is correct and a time measuring means for measuring the propagation time of the ultrasonic wave. 比較手段は基準値に対して2つの閾値で受信波形との比較を行い、判断手段は前記比較手段の結果が2つの閾値のどちらから先に検知したかを判断するようにした請求項1記載の流体の流れ計測装置。 2. The comparison unit according to claim 1, wherein the comparison unit compares the received waveform with two threshold values with respect to a reference value, and the determination unit determines which of the two threshold values is detected first. Fluid flow measuring device. 計時手段を有し、2つの閾値の1つで比較されてから、もう一つの閾値で比較されるまでの時間を計時することで、比較手段の信号の正誤を判断手段で判断するようにした請求項2記載の流体の流れ計測装置。 It has time measuring means, and the time from comparison between one of the two thresholds to comparison with the other threshold is counted, so that the correctness of the signal of the comparison means is judged by the judging means. The fluid flow measuring device according to claim 2. 閾値を切換えて、複数の閾値で比較できるようにした比較手段を備えた請求項2記載の流体の流れ計測装置。 The fluid flow measuring device according to claim 2, further comprising a comparison unit configured to switch the threshold values and to compare with a plurality of threshold values. 一方の超音波センサから他方の超音波センサへ送信した時の超音波の伝播時間T1と、逆方向に送信した時の超音波の伝播時間T2との伝播時間差にもとづいて流速および/または流量を求めるようにし、受信波の波数を求めて、波数の比較で受信波の正誤を判断する判断手段を備えた請求項1記載の流体の流れ計測装置。 The flow velocity and / or flow rate is determined based on the propagation time difference between the ultrasonic propagation time T1 when transmitted from one ultrasonic sensor to the other ultrasonic sensor and the ultrasonic propagation time T2 when transmitted in the opposite direction. The fluid flow measuring device according to claim 1, further comprising: a determination unit configured to determine the wave number of the received wave, and to determine whether the received wave is correct by comparing the wave numbers. 判断手段はピークホールド回路を有し、このピークホールド回路のピーク値更新回数で波数比較を行うようにした請求項5記載の流体の流れ計測装置。 6. The fluid flow measuring device according to claim 5, wherein the judging means includes a peak hold circuit, and the wave number comparison is performed based on the number of times the peak value of the peak hold circuit is updated. 判断手段は受信波のピークを検知するピークホールド回路と比較手段を有し、この比較手段は前記ピークホールド回路出力と受信波とを比較して、波数を求めるためのパルス信号を形成する構成とした請求項6記載の流体の流れ計測装置。 The judging means has a peak hold circuit for detecting the peak of the received wave and a comparing means, and the comparing means compares the peak hold circuit output with the received wave to form a pulse signal for obtaining the wave number; The fluid flow measuring device according to claim 6. 計時手段を有し、波数を求めるために形成されたパルス間隔の時間を計時することで、形成されたパルス信号の正誤を判断手段で判断するようにした請求項7記載の流体の流れ計測装置。 8. The fluid flow measuring device according to claim 7, further comprising a time measuring unit, wherein the determination unit determines whether the formed pulse signal is correct by measuring the time of the pulse interval formed to determine the wave number. .
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008185441A (en) * 2007-01-30 2008-08-14 Matsushita Electric Ind Co Ltd Ultrasonic flowmeter
KR101097405B1 (en) * 2009-03-31 2011-12-23 한국수자원공사 Non-intrusive ultrasonic current meter
JP2016099116A (en) * 2014-11-18 2016-05-30 愛知時計電機株式会社 Ultrasonic flowmeter
JP2020063972A (en) * 2018-10-17 2020-04-23 アズビル株式会社 Ultrasonic flowmeter, flow rate measuring method, flow rate calculating device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57124211A (en) * 1981-01-26 1982-08-03 Yokogawa Hokushin Electric Corp Ultrasonic measuring device
JPS6120821A (en) * 1984-07-10 1986-01-29 Yokogawa Hokushin Electric Corp Ultrasonic flowmeter
JP2002340641A (en) * 2001-05-11 2002-11-27 Matsushita Electric Ind Co Ltd Instrument for measuring flow rate
JP2004069524A (en) * 2002-08-07 2004-03-04 Matsushita Electric Ind Co Ltd Flow rate measuring apparatus
WO2004048902A1 (en) * 2002-11-26 2004-06-10 Matsushita Electric Industrial Co., Ltd. Ultrasonic flowmeter and ultrasonic flow rate measuring method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57124211A (en) * 1981-01-26 1982-08-03 Yokogawa Hokushin Electric Corp Ultrasonic measuring device
JPS6120821A (en) * 1984-07-10 1986-01-29 Yokogawa Hokushin Electric Corp Ultrasonic flowmeter
JP2002340641A (en) * 2001-05-11 2002-11-27 Matsushita Electric Ind Co Ltd Instrument for measuring flow rate
JP2004069524A (en) * 2002-08-07 2004-03-04 Matsushita Electric Ind Co Ltd Flow rate measuring apparatus
WO2004048902A1 (en) * 2002-11-26 2004-06-10 Matsushita Electric Industrial Co., Ltd. Ultrasonic flowmeter and ultrasonic flow rate measuring method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008185441A (en) * 2007-01-30 2008-08-14 Matsushita Electric Ind Co Ltd Ultrasonic flowmeter
KR101097405B1 (en) * 2009-03-31 2011-12-23 한국수자원공사 Non-intrusive ultrasonic current meter
JP2016099116A (en) * 2014-11-18 2016-05-30 愛知時計電機株式会社 Ultrasonic flowmeter
JP2020063972A (en) * 2018-10-17 2020-04-23 アズビル株式会社 Ultrasonic flowmeter, flow rate measuring method, flow rate calculating device

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