JP2910815B2 - Measuring method of flow velocity in pipe using ultrasonic current meter - Google Patents
Measuring method of flow velocity in pipe using ultrasonic current meterInfo
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- JP2910815B2 JP2910815B2 JP31568893A JP31568893A JP2910815B2 JP 2910815 B2 JP2910815 B2 JP 2910815B2 JP 31568893 A JP31568893 A JP 31568893A JP 31568893 A JP31568893 A JP 31568893A JP 2910815 B2 JP2910815 B2 JP 2910815B2
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- Prior art keywords
- flow
- ultrasonic
- exclusive
- pipe
- phase difference
- Prior art date
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- Measuring Volume Flow (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、超音波流速計を用いた
管内流速の測定方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a flow velocity in a pipe using an ultrasonic flow meter.
【０００２】[0002]
【従来の技術】管内を流れる流体、たとえば上水の流速
を測定するために、超音波流量計を用いることが知られ
ている。この超音波流量計は、超音波が流体中を伝搬す
るときに、その伝搬速度は、静止流体中の音速と流体の
流速とのベクトル和になることを利用している。2. Description of the Related Art It is known to use an ultrasonic flowmeter to measure the flow rate of a fluid flowing in a pipe, for example, tap water. This ultrasonic flow meter utilizes that when an ultrasonic wave propagates through a fluid, the propagation speed is a vector sum of the sound velocity in the stationary fluid and the flow velocity of the fluid.
【０００３】図３は、その測定原理を示す。図示のよう
に、管内の上流側の管内面に第１の超音波送信器１１を
設置するとともに、これより管軸方向に距離Ｌをおいた
下流側の管内面には、第１の超音波受信器１２を設置し
て、送信器１１から送信された超音波１３が、径方向の
反対側の管内面で反射して、受信器１２で受信されるよ
うに構成されている。一方、第１の超音波送信器１１に
対応する位置には第２の超音波受信器１４が設置され、
また第１の超音波受信器１２に対応する位置には第２の
超音波送信器１５が設置されて、反対方向すなわち下流
側から上流側に向けて超音波を送ることができるように
されている。換言すると、２対の超音波センサにより同
時に送受信を行うように構成されている。FIG. 3 shows the principle of the measurement. As shown in the drawing, a first ultrasonic transmitter 11 is installed on the inner surface of the upstream tube, and the first ultrasonic transmitter 11 is disposed on the inner surface of the downstream tube at a distance L in the axial direction of the tube. The receiver 12 is installed so that the ultrasonic waves 13 transmitted from the transmitter 11 are reflected on the inner surface of the tube on the opposite side in the radial direction and are received by the receiver 12. On the other hand, a second ultrasonic receiver 14 is installed at a position corresponding to the first ultrasonic transmitter 11,
A second ultrasonic transmitter 15 is provided at a position corresponding to the first ultrasonic receiver 12 so that ultrasonic waves can be transmitted in the opposite direction, that is, from the downstream side to the upstream side. I have. In other words, transmission and reception are performed simultaneously by two pairs of ultrasonic sensors.
【０００４】このようにすれば、流れの方向での伝搬時
間と逆方向での伝搬時間との差から、管内流体の流速を
求めることができる（複流法、時間差法）。連続波を送
受信する場合には、伝搬時間の差を位相差に置き換える
ことで、流速が求められる（位相差法）。In this way, the flow velocity of the fluid in the pipe can be obtained from the difference between the propagation time in the flow direction and the propagation time in the opposite direction (double flow method, time difference method). In the case of transmitting and receiving a continuous wave, the flow velocity is obtained by replacing the difference in propagation time with the phase difference (phase difference method).
【０００５】以下、この位相差法の原理について説明す
る。まず、図３において、上流側から下流側への超音波
の伝搬を考える。すると、伝搬ベクトルは、Hereinafter, the principle of the phase difference method will be described. First, in FIG. 3, the propagation of ultrasonic waves from the upstream side to the downstream side is considered. Then the propagation vector is
【０００６】[0006]
【数２】 (Equation 2)
【０００７】となる。これをスカラ一量で表わすと、角
度θ，βを用いて、[0007] Expressing this as a scalar quantity, using the angles θ and β,
【０００８】[0008]
【数３】 (Equation 3)
【０００９】となる。ここで、ａsin θ＝ｖsin βであ
るから、## EQU1 ## Here, since asin θ = vsin β,
【００１０】[0010]
【数４】 (Equation 4)
【００１１】となる。（３）式を（２）式に代入する
と、## EQU1 ## Substituting equation (3) into equation (2) gives
【００１２】[0012]
【数５】 (Equation 5)
【００１３】となる。ここで、具体的にはａ＝１４５０
〜１５００ｍ／ｓ，ｖ＝０〜３ｍ／ｓであり、よってａ
≫ｖであるから、## EQU1 ## Here, specifically, a = 1450
１1500 m / s, v = 0０〜3 m / s, thus a
Since ≫v,
【００１４】[0014]
【数６】 (Equation 6)
【００１５】となり、したがって（４）式は、Therefore, equation (4) becomes
【００１６】[0016]
【数７】 (Equation 7)
【００１７】となる。伝搬距離ＡＣＢはＬ／cos βとな
るため、伝搬時間ｔは、## EQU1 ## Since the propagation distance ACB is L / cos β, the propagation time t is
【００１８】[0018]
【数８】 (Equation 8)
【００１９】となる。次に、流れとは逆方向、すなわち
下流側から上流側への超音波の伝搬について考える。こ
のとき、伝搬速度をＶ′、伝搬時間をｔ′とすると、## EQU1 ## Next, the propagation of the ultrasonic wave in the direction opposite to the flow, that is, from the downstream side to the upstream side will be considered. At this time, if the propagation speed is V 'and the propagation time is t',
【００２０】[0020]
【数９】 (Equation 9)
【００２１】となる。（７）（９）式より、伝搬時間の
差Δｔは、## EQU1 ## (7) From equation (9), the difference Δt in the propagation time is
【００２２】[0022]
【数10】 [Equation 10]
【００２３】しかし、ａ2 ≫ｖ2 であるから、結局、However, since a 2 ≫v 2 , after all,
【００２４】[0024]
【数11】 [Equation 11]
【００２５】となる。これを位相差：Δφで表すと、超
音波の周波数をｆとして、## EQU1 ## If this is represented by a phase difference: Δφ, the frequency of the ultrasonic wave is f, and
【００２６】[0026]
【数12】 (Equation 12)
【００２７】となり、結局（１１）式より、Then, from the equation (11),
【００２８】[0028]
【数13】 (Equation 13)
【００２９】となる。## EQU1 ##
【００３０】[0030]
【発明が解決しようとする課題】しかし、従来において
は、上述の位相差を適当に測定して数量化する手だてが
無く、上記（１２）式を用いて管内流体の流速を測定す
ることが困難であるという問題点が存在する。また、流
速だけでなく、流れの向きの測定にも困難を伴うという
問題点がある。However, conventionally, there is no means for appropriately measuring and quantifying the above-mentioned phase difference, and it is difficult to measure the flow velocity of the fluid in the pipe using the above equation (12). Is a problem. In addition, there is a problem that it is difficult to measure not only the flow velocity but also the direction of the flow.
【００３１】そこで本発明はこのような問題点を解決
し、流れの方向とその逆の方向での超音波の伝搬時間の
差を表わす位相差を容易に求め得るとともに、その流れ
の向きをも容易に求め得るようにすることを目的とす
る。Accordingly, the present invention solves such a problem, and can easily obtain a phase difference representing a difference between the propagation times of ultrasonic waves in the direction of the flow and the opposite direction, and can also determine the direction of the flow. It is intended to be easily obtainable.
【００３２】[0032]
【課題を解決するための手段】上記目的を達成するため
本発明は、超音波として矩形状の連続波を使用し、流れ
の方向の受信波と流れとは逆の方向の受信波との排他的
論理和を求めて、得られた第１の排他的論理和を平滑化
し、両受信波のうちの一方の位相をずらせ、この位相の
ずれた受信波と他方の受信波との排他的論理和を求め
て、得られた第２の排他的論理和を平滑化し、前記第１
の排他的論理和を平滑化した結果の大きさから求められ
る複数の位相差と、前記第２の排他的論理和を平滑化し
た結果の大きさから求められる複数の位相差とのうち、
互いに対応するものを用いて、上記（１２）式を用いた
流速の測定を行うとともに、その流れの向きの測定を行
うものである。In order to achieve the above object, the present invention uses a rectangular continuous wave as an ultrasonic wave and excludes a received wave in a flow direction and a received wave in a direction opposite to the flow. A first logical sum is obtained, the obtained first exclusive logical sum is smoothed, the phase of one of the received waves is shifted, and the exclusive logical sum of the received wave shifted in phase and the other received wave is obtained. The sum is obtained, the obtained second exclusive OR is smoothed, and the first
Of the plurality of phase differences obtained from the magnitude of the result of smoothing the exclusive OR of the two and the plurality of phase differences obtained from the magnitude of the result of smoothing the second exclusive OR,
The flow rate is measured using the above equation (12) and the direction of the flow is measured using the mutually corresponding ones.
【００３３】[0033]
【作用】このようにすれば、流れの方向の受信波と流れ
とは逆の方向の受信波との排他的論理和には、両受信波
の位相差に関する情報が含まれる。したがって、この排
他的論理和を平滑化することで位相差の大きさが求ま
り、その結果、上記の（１２）式を用いて管内流体の流
速が求められる。In this way, the exclusive OR of the received wave in the direction of the flow and the received wave in the direction opposite to the flow includes information on the phase difference between the two received waves. Therefore, the magnitude of the phase difference is obtained by smoothing the exclusive OR, and as a result, the flow velocity of the fluid in the pipe is obtained using the above equation (12).
【００３４】ここで、単に流れの方向の受信波と流れと
は逆の方向の受信波との排他的論理和を平滑化しただけ
のデータには、そのときの流れの方向に応じた位相差に
ついての情報と、逆向きの流れに対応した位相差につい
ての情報とが、ともに含まれる。このため、これだけで
は、管内流体の流れの向きを判定することができない。Here, the data obtained by simply smoothing the exclusive OR of the received wave in the direction of flow and the received wave in the direction opposite to the flow has a phase difference corresponding to the direction of flow at that time. , And information about the phase difference corresponding to the reverse flow. For this reason, it is not possible to determine the direction of the flow of the fluid in the pipe by this alone.
【００３５】そこで本発明のように一方の受信波の位相
をずらせたうえで別に排他的論理和を求めて平滑化する
ことにより、そこから求められるデータには位相差の正
負に関する情報が含まれることになる。このため、位相
をずらせなかった場合とずらせた場合とにおいて互いに
対応する位相差を選ぶことにより、正負の情報を含んだ
位相差が決定され、これによって管内流体の流れの向き
が判定される。Therefore, as in the present invention, the phase of one of the received waves is shifted and then exclusive-OR is separately obtained and smoothed, so that the data obtained therefrom includes information on the sign of the phase difference. Will be. Therefore, a phase difference including positive and negative information is determined by selecting a phase difference corresponding to the case where the phase is not shifted and the case where the phase is shifted, and thereby the direction of the flow of the fluid in the pipe is determined.
【００３６】[0036]
【実施例】図１は、本発明にもとづいて位相差を流れの
向きとともに求めるための具体的な手法の一例を示す。
流れの方向の受信波Ｗ１と流れとは逆の方向の受信波Ｗ
２とは、ともに同一周波数ｆの矩形波で、いずれもデュ
ーティー比は５０であって、πラジアンごとに所定の出
力Ｖｏ（ボルト）が生じたり、生じずに０になったりす
る。上述の説明の通り、受信波Ｗ１と受信波Ｗ２との間
には、管内流体の流速にもとづく位相差Δφが存在す
る。FIG. 1 shows an example of a specific method for obtaining a phase difference together with a flow direction according to the present invention.
Received wave W1 in the direction of flow and received wave W in the direction opposite to the flow
Numerals 2 are both rectangular waves having the same frequency f, each having a duty ratio of 50, and a predetermined output Vo (volt) is generated every π radians or becomes zero without being generated. As described above, there is a phase difference Δφ between the reception wave W1 and the reception wave W2 based on the flow velocity of the fluid in the pipe.
【００３７】両受信波Ｗ１，Ｗ２の排他的論理和Ｗ１
XOR Ｗ２は、図示のようになる。そこで、この排他的
論理和についての信号を公知の手段によって平滑化する
と、破線で示されるその値Ｖ１２は、Ｖ１２＝（Δφ／
π）・Ｖｏとなり、位相差を電圧に変換することができ
て、その大きさを求めることができる。Exclusive OR W1 of both received waves W1, W2
XOR W2 is as shown in the figure. Therefore, when the signal about the exclusive OR is smoothed by a known means, the value V12 indicated by the broken line is V12 = (Δφ /
π) · Vo, the phase difference can be converted to a voltage, and the magnitude can be obtained.
【００３８】この位相差Δφと、Ｗ１ XOR Ｗ２を平
滑化した電圧との関係を、図２に示す。位相差が−π〜
πラジアンの範囲では、図において実線で示すようにＶ
字状に電圧が変化する。このため、この位相差−電圧の
関係をあらかじめ調べておけば、反対にその平滑化した
電圧を求めることによって、そのときの位相差Δφを知
ることができる。FIG. 2 shows the relationship between the phase difference Δφ and the voltage obtained by smoothing W1 XOR W2. Phase difference is -π ~
In the range of π radians, as shown by a solid line in FIG.
The voltage changes like a letter. Therefore, if the relationship between the phase difference and the voltage is checked in advance, the phase difference Δφ at that time can be known by obtaining the smoothed voltage.
【００３９】ところで、図２に示すように、電圧の変化
は位相差０を中心とするＶ字状となるため、同一電圧
に、正負ふたつの位相差Δφが対応する。この位相差Δ
φの正負は管内流体の流れの方向に対応するものであ
り、単に平滑化した結果の電圧を求めただけでは、この
位相差の正負すなわち流れの方向は判定することができ
ない。By the way, as shown in FIG. 2, since the voltage changes in a V-shape with a phase difference of 0 as the center, two positive and negative phase differences Δφ correspond to the same voltage. This phase difference Δ
The sign of φ corresponds to the direction of the flow of the fluid in the pipe, and the sign of this phase difference, that is, the direction of the flow, cannot be determined simply by obtaining the voltage resulting from smoothing.
【００４０】そこで、両受信波Ｗ１，Ｗ２のうちの一方
につき、公知の手段を用いてその位相をずらせる。図１
には、受信波Ｗ１の位相を＋π／２だけずらせた信号Ｗ
１′が示されている。そして、この位相をずらせた信号
Ｗ１と、他方の受信波Ｗ２との排他的論理和Ｗ１′XOR
Ｗ２をとると、図示のようになる。破線で示されるＶ
１２′は、この排他的論理和を平滑化した電圧を示す。Therefore, the phase of one of the two received waves W1 and W2 is shifted using known means. FIG.
The signal W obtained by shifting the phase of the received wave W1 by + π / 2.
1 'is shown. Then, the exclusive OR W1'XOR of the signal W1 with this phase shifted and the other received wave W2 is obtained.
When W2 is taken, it becomes as shown in the figure. V indicated by broken line
Reference numeral 12 'indicates a voltage obtained by smoothing the exclusive OR.
【００４１】位相差Δφと電圧Ｖ１２′との関係を、図
２において破線で示す。この破線は、実線を＋π／２だ
けシフトさせたものに相当する。すなわち、排他的論理
和Ｗ１ XOR Ｗ２が電圧Ｖ１２の値をとり、かつ排他
的論理和Ｗ１′ XOR Ｗ２が電圧Ｖ１２′の値をとる場
合には、そのときの位相差Δφ１２は図示のように一義
的に定まり、この図示の例では位相差Δφ１２は＋側に
存在している。 このようにして位相差Δφ１２を求め
ることにより、これを用いて（１２）式により管内流体
の流速ｖを測定することができる。その際には、位相差
Δφが−π〜πとなるように、測定対象に応じて適宜に
距離Ｌと周波数ｆとを選定すればよい。また上述のよう
に正負の別を明らかにしたうえで位相差Δφ１２を求め
ることで、管内流体の流れの方向を判定することができ
る。The relationship between the phase difference Δφ and the voltage V12 'is shown by a broken line in FIG. This broken line corresponds to the solid line shifted by + π / 2. That is, when the exclusive OR W1 XOR W2 takes the value of the voltage V12 and the exclusive OR W1 'XOR W2 takes the value of the voltage V12', the phase difference Δφ12 at that time is unambiguous as shown in the figure. In the illustrated example, the phase difference Δφ12 exists on the + side. By calculating the phase difference Δφ12 in this manner, the flow rate v of the fluid in the pipe can be measured by using the phase difference Δφ12 according to the equation (12). In this case, the distance L and the frequency f may be appropriately selected according to the measurement target so that the phase difference Δφ is −π to π. In addition, the direction of the flow of the fluid in the pipe can be determined by determining the phase difference Δφ12 after clarifying the difference between positive and negative as described above.
【００４２】[0042]
【発明の効果】以上述べたように本発明によると、超音
波を用いて管内流速を測定するに際し、流れの方向の受
信波と流れとは逆の方向の受信波との排他的論理和を平
滑化して両波の位相差を測定するため、この位相差の大
きさを簡単に求めることができて、管内流体の流速を容
易に測定することができるのみならず、一方の受信波の
位相をずらせて別に排他的論理和を求めて平滑化し、こ
れと先の平滑化された値とによって、正負の別を明らか
にしたうえで位相差の大きさを求めることができ、この
ため流速に加えて流れの向きをも測定することができ
る。As described above, according to the present invention, when measuring the flow velocity in a pipe using ultrasonic waves, the exclusive OR of the received wave in the flow direction and the received wave in the opposite direction to the flow is calculated. Since the phase difference between the two waves is measured after smoothing, the magnitude of the phase difference can be easily obtained, so that not only the flow velocity of the fluid in the pipe can be easily measured but also the phase of one of the received waves. , The exclusive OR is calculated separately and smoothed, and the magnitude of the phase difference can be obtained after clarifying the difference between positive and negative by using this and the smoothed value. In addition, the direction of the flow can be measured.
【図１】本発明の一実施例の管内流速の位相差測定方法
における位相差の大きさおよび正負を求める手法を説明
する図である。FIG. 1 is a diagram for explaining a method for determining the magnitude and the sign of a phase difference in a method for measuring a phase difference of a flow velocity in a pipe according to an embodiment of the present invention.
【図２】位相差と、両受信波の排他的論理和を平滑化し
た電圧との関係を示す図である。FIG. 2 is a diagram illustrating a relationship between a phase difference and a voltage obtained by smoothing an exclusive OR of both received waves.
【図３】従来の超音波流速計の原理図である。FIG. 3 is a principle diagram of a conventional ultrasonic current meter.
Ｗ１ 流れの方向の受信波 Ｗ２ 逆の方向の受信波 W1 Received wave in flow direction W2 Received wave in reverse direction
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭58−7523（ＪＰ，Ａ) 特開 昭58−176521（ＪＰ，Ａ) 特開 昭58−32121（ＪＰ，Ａ) 特開 昭58−32123（ＪＰ，Ａ) 特開 昭61−128176（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01F 1/66 101 G01P 13/00 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-7523 (JP, A) JP-A-58-176521 (JP, A) JP-A-58-32121 (JP, A) JP-A-58-75 32123 (JP, A) JP-A-61-128176 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) G01F 1/66 101 G01P 13/00
Claims (1)
２の超音波受信器とを設置するとともに、管内の下流側
に第２の超音波送信器と第１の超音波受信器とを設置し
て、第１および第２の超音波送信器からそれぞれ送信さ
れる超音波を第１および第２の超音波受信器にてそれぞ
れ受信し、両受信器で受信された流れの方向の受信波と
流れとは逆の方向の受信波との位相差から下記（ｉ）式
にもとづいて管内流体の流速を測定するに際し、 【数１】 超音波として矩形状の連続波を使用し、 流れの方向の受信波と流れとは逆の方向の受信波との排
他的論理和を求めて、得られた第１の排他的論理和を平
滑化し、 両受信波のうちの一方の位相をずらせ、 この位相のずれた受信波と他方の受信波との排他的論理
和を求めて、得られた第２の排他的論理和を平滑化し、 前記第１の排他的論理和を平滑化した結果の大きさから
求められる複数の位相差と、前記第２の排他的論理和を
平滑化した結果の大きさから求められる複数の位相差と
のうち、互いに対応するものを用いて、上記（ｉ）式を
用いた流速の測定を行うとともに、その流れの向きの測
定を行う、 ことを特徴とする超音波流速計を用いた管内流速の測定
方法。1. A first ultrasonic transmitter and a second ultrasonic receiver are installed on an upstream side of a pipe, and a second ultrasonic transmitter and a first ultrasonic receiver are installed on a downstream side of the pipe. And the first and second ultrasonic receivers respectively receive ultrasonic waves transmitted from the first and second ultrasonic transmitters, respectively. When measuring the flow velocity of the fluid in the pipe based on the following equation (i) from the phase difference between the received wave in the direction and the received wave in the direction opposite to the flow, A rectangular continuous wave is used as an ultrasonic wave, and an exclusive OR of a received wave in a flow direction and a received wave in a direction opposite to the flow is obtained, and the obtained first exclusive OR is smoothed. The phase of one of the received waves is shifted, the exclusive OR of this phase shifted received wave and the other received wave is obtained, and the obtained second exclusive OR is smoothed. A plurality of phase differences obtained from the magnitude of the result obtained by smoothing the first exclusive OR, and a plurality of phase differences obtained from the magnitude of the result obtained by smoothing the second exclusive OR Among them, those corresponding to each other are used to measure the flow velocity using the above equation (i) and to measure the direction of the flow.
The constant, the tube flow rate measuring method using an ultrasonic current meter, characterized in that.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31568893A JP2910815B2 (en) | 1993-12-16 | 1993-12-16 | Measuring method of flow velocity in pipe using ultrasonic current meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31568893A JP2910815B2 (en) | 1993-12-16 | 1993-12-16 | Measuring method of flow velocity in pipe using ultrasonic current meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07167695A JPH07167695A (en) | 1995-07-04 |
| JP2910815B2 true JP2910815B2 (en) | 1999-06-23 |
Family
ID=18068365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31568893A Expired - Fee Related JP2910815B2 (en) | 1993-12-16 | 1993-12-16 | Measuring method of flow velocity in pipe using ultrasonic current meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2910815B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0503422D0 (en) * | 2005-02-18 | 2005-03-30 | Univ Cranfield | A flowmeter |
| CN104748805A (en) * | 2015-04-10 | 2015-07-01 | 吉安精程仪表科技有限公司 | Ultrasonic flow measurement method based on direct phase difference |
-
1993
- 1993-12-16 JP JP31568893A patent/JP2910815B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07167695A (en) | 1995-07-04 |
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