JPH10281832A - Pulse doppler type ultrasonic flowmeter - Google Patents
Pulse doppler type ultrasonic flowmeterInfo
- Publication number
- JPH10281832A JPH10281832A JP9089088A JP8908897A JPH10281832A JP H10281832 A JPH10281832 A JP H10281832A JP 9089088 A JP9089088 A JP 9089088A JP 8908897 A JP8908897 A JP 8908897A JP H10281832 A JPH10281832 A JP H10281832A
- Authority
- JP
- Japan
- Prior art keywords
- flow velocity
- current distribution
- velocity distribution
- flow rate
- flow
- 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.)
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- Measuring Volume Flow (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、流量測定法に係わ
り、例えば、上水道・雨水排水・農業用水等のために用
いられる流体機械のパルスドップラ式超音波流量計に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow measurement method, and more particularly to a pulse Doppler type ultrasonic flow meter for a fluid machine used for water supply, rainwater drainage, agricultural water, and the like.
【０００２】[0002]
【従来の技術】従来この種の流量測定方法において、パ
ルスドップラ式超音波方式のものとしては、例えば、特
開平8−125633 号公報に記載のものがある。本方式によ
れば、例えば図４に示すようにポンプ吐出管の外壁１に
１個の超音波送受波器２を取り付け、そこからバースト
状（幾つかのパルス波）の超音波３を発信し、管内の微
小粒子４ａ，４ｂ等から散乱される超音波５ａ，５ｂ等
を上記の送受波器２で受信する。その受信波には微小粒
子の超音波の進行方向の移動速度Ｖbcosθすなわち流速
に基づく周波数Δｆのドップラシフトを受けた信号が入
っており、周波数分析によりΔｆを求め、次式から流速
Ｖが検出される。2. Description of the Related Art Conventionally, in this type of flow rate measuring method, a pulse Doppler ultrasonic method is described in, for example, JP-A-8-125633. According to this method, for example, as shown in FIG. 4, one ultrasonic transducer 2 is attached to the outer wall 1 of the pump discharge pipe, and burst (several pulse waves) ultrasonic waves 3 are transmitted therefrom. The ultrasonic waves 5a, 5b, etc., scattered from the microparticles 4a, 4b, etc. in the tube are received by the transducer 2. The received wave contains a signal that has undergone a Doppler shift of the frequency Δf based on the moving velocity V b cosθ of the microparticles in the traveling direction of the ultrasonic wave, that is, the flow velocity, and Δf is obtained by frequency analysis. Is detected.
【０００３】[0003]
【数１】 Ｖ＝ＣΔｆ／２ｆ0cosθ …（数１） ここに、Ｃ：水の音速、ｆ0 ：送信超音波の周波数，Δ
ｆ：ドップラシフト周波数，θ：超音波の進行方向と管
壁とのなす角度である。検出位置Ｌは次式により求めら
れる。V = CΔf / 2f 0 cosθ (Equation 1) where C: sound velocity of water, f 0 : frequency of transmitted ultrasonic wave, Δ
f: Doppler shift frequency, θ: angle between the traveling direction of the ultrasonic wave and the tube wall. The detection position L is obtained by the following equation.
【０００４】[0004]
【数２】 Ｌ＝Ｃ・ｔ・sinθ／２ …（数２） ここに、ｔ：ゲート時間である。この信号取り込のゲー
ト時間を変化させると、超音波が送受波器から往復する
時間が変わり、測定する位置を変えることができる。こ
のように、管内の測定位置はゲート時間を変えることに
より、その位置の流速はドップラ信号で検出することが
可能で、すなわち、管内の流速分布を測定できることに
なる。得られた流速分布を管断面に対して積分すること
により流量が得られる。１個の送受波器で流速分布に基
づく流量が得られるので、使い勝手がよく且つ高い測定
精度の流量計を得ることができる。L = C · t · sin θ / 2 (Equation 2) where t is a gate time. If the gate time of the signal acquisition is changed, the time for the ultrasonic wave to reciprocate from the transducer changes, and the measurement position can be changed. Thus, by changing the gate time at the measurement position in the pipe, the flow velocity at that position can be detected by the Doppler signal, that is, the flow velocity distribution in the pipe can be measured. The flow rate is obtained by integrating the obtained flow velocity distribution with respect to the pipe section. Since a flow rate based on the flow velocity distribution can be obtained with one transducer, a flow meter with good usability and high measurement accuracy can be obtained.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記従
来技術には以下の課題が存在する。図５左に示すような
断面が円形の配管についてパルスドップラ式超音波流量
計で検出した場合の管内の流速分布の結果の一例を図５
右に示す。この図に示されるように送受波器側の管壁近
傍のＸｎの領域には、乱れた流速分布（Ａ）が検出され
る場合がある。これは、超音波の送受波器２内の超音波
素子２ａから出た超音波が、送受波器端面２ｂ（あるい
は管の外壁面１ａ）や管の内壁面１ｂで反射し、管内の
粒子から散乱された正規の超音波信号に対して大きなノ
イズとなり、ドップラ信号が正しく得られないからであ
る。このような影響は、超音波素子２ａの端面と流路壁
内面１ｂの距離Ｌ0 が流路の測定距離Ｌに比べ無視でき
ない場合に問題となる。However, the above prior art has the following problems. FIG. 5 shows an example of a result of a flow velocity distribution in a pipe when a pulse Doppler ultrasonic flowmeter detects a pipe having a circular cross section as shown in FIG.
Shown on the right. As shown in this figure, a disturbed flow velocity distribution (A) may be detected in the area Xn near the tube wall on the transducer side. This is because the ultrasonic wave emitted from the ultrasonic element 2a in the ultrasonic transducer 2 is reflected on the transducer end face 2b (or the outer wall surface 1a of the tube) or the inner wall surface 1b of the tube, and from the particles in the tube. This is because the scattered normal ultrasonic signal becomes large noise and a Doppler signal cannot be obtained correctly. Such effects are a problem when the distance L 0 of the end face and the channel wall inner surface 1b of the ultrasonic element 2a is not negligible compared with the measured distance L of the channel.
【０００６】このノイズを低減するには超音波素子２ａ
の端面から流路壁内面１ａの距離Ｌ0 を小さくしたり、
材質の音響インピーダンス（密度×音速）を流路内の液
体と同じにする必要がある。しかし、このような方策を
実施することは極めて困難である。というのは、距離Ｌ
0 を小さくするには超音波素子２ａの直径を小さくする
必要がある。しかし、直径を小さくすると超音波の出力
が小さくなり鋼鉄製の流路壁１を超音波が透過できなく
なり、あるいは透過できても散乱波の強度が弱いため受
信波を受信できなくなり、管内の流速を得ることができ
なくなる。一方、材質の音響インピーダンスを測定対象
の流体の水と同じにすることは、管壁に穴をあけて樹脂
製の窓を設置してそこに超音波送受波器を設置する必要
がある。このようなことは既存のポンプの流量を測定す
る場合は、極めて困難である。To reduce this noise, the ultrasonic element 2a
Or by reducing the distance L 0 of the channel wall inner surface 1a from the end surface of,
The acoustic impedance (density x sound velocity) of the material must be the same as the liquid in the flow path. However, it is extremely difficult to implement such measures. Because the distance L
To reduce 0 , it is necessary to reduce the diameter of the ultrasonic element 2a. However, when the diameter is reduced, the output of the ultrasonic wave becomes small, and the ultrasonic wave cannot pass through the steel channel wall 1, or even if it can pass, the intensity of the scattered wave is weak, so that the received wave cannot be received, and the flow velocity in the pipe is reduced. Can not be obtained. On the other hand, in order to make the acoustic impedance of the material the same as that of the fluid to be measured, it is necessary to make a hole in the tube wall, install a resin window, and install an ultrasonic transducer in the window. This is extremely difficult when measuring the flow rate of an existing pump.
【０００７】[0007]
【課題を解決するための手段】検出された流速分布を積
分して流量を算出する際、測定精度が悪い送受波器側の
管壁近傍の流速データ（Ａ）は適用せず、管璧近傍以外
の精度よく検出された流速分布データ（Ｂ）から管壁近
傍の流速分布データ（Ｃ）を外挿して求め、上記の流速
分布データ（Ｂ）と（Ｃ）から流量を算出する。When calculating the flow rate by integrating the detected flow velocity distribution, the flow velocity data (A) near the tube wall on the side of the transducer having poor measurement accuracy is not applied, and the flow rate data near the pipe wall is not applied. The flow velocity distribution data (C) near the pipe wall is extrapolated from the flow velocity distribution data (B) detected with high accuracy other than the above, and the flow rate is calculated from the above flow velocity distribution data (B) and (C).
【０００８】[0008]
【発明の実施の形態】本発明の第１の実施形態を図１に
より説明する。流路１の外壁面に超音波送受波器（セン
サ）２を取り付け、送受波器２には従来技術のパルスド
ップラ式超音波流速計６が接続されている。本流速計６
には流速分布の表示・修正器７ａ及び流速分布から積分
して流量を求める流量算出器７ｂからなる流量修正装置
７が接続されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. An ultrasonic transducer (sensor) 2 is attached to the outer wall surface of the flow path 1, and a conventional pulse Doppler ultrasonic velocity meter 6 is connected to the transducer 2. Main current meter 6
Is connected to a flow rate correction device 7 including a flow rate distribution display / correction unit 7a and a flow rate calculation unit 7b for integrating the flow rate distribution to obtain a flow rate.
【０００９】このような流量測定装置において、パルス
ドップラ式超音波流速計６の出力として、流路の半径方
向と流速との関係すなわち軸方向流速の半径方向の分布
図として図２に示す実線の曲線が得られる。すなわち、
送受波器側管壁近傍の領域Ｘｎの範囲の流速分布曲線
（Ａ）は、送受波器と流路壁の材料と流路内の液の音響
インピーダンスが異なるため、それぞれの境界面で反射
するノイズにより、正規の流速分布非常に異なった分布
形状を呈する場合がある。しかし、実際の流速分布はこ
のように短い半径方向距離で凹凸を示すことはなく、境
界層の発達により流路中心から管璧に向かって流速は漸
減する傾向を示す。従って、このように実際の流れを示
していない（Ａ）の流速分布を用いて流量を算出する
と、正しい流量が得られない。In such a flow rate measuring device, the output of the pulse Doppler ultrasonic flow meter 6 is shown by the solid line shown in FIG. A curve is obtained. That is,
The flow velocity distribution curve (A) in the region Xn in the vicinity of the tube wall on the transducer side is reflected at each boundary surface because the acoustic impedance of the material of the transducer and the wall of the flow path and the acoustic impedance of the liquid in the flow path are different. Due to noise, the normal flow velocity distribution may have a very different distribution shape. However, the actual flow velocity distribution does not show irregularities at such a short radial distance, and the flow velocity tends to gradually decrease from the center of the flow path toward the pipe wall due to the development of the boundary layer. Therefore, when the flow rate is calculated using the flow velocity distribution (A) that does not indicate the actual flow, a correct flow rate cannot be obtained.
【００１０】一方、管壁から離れたＸｍの領域では上記
のノイズの影響が小さくなるので正常な流速分布（Ｂ）
が検出される。そこで、流速分布表示・修正器により、
正常に検出された流速分布（Ｂ）を正にして領域Ｘｎ側
に外挿して流速分布（Ｃ）を数値解析的に求める。外挿
は、流速分布（Ｂ）を例えば最少二乗法で２〜３次曲線
で近似し、その曲線を用いて領域Ｘｎの流速データが求
めることにより行われる。このような外挿により得られ
た流速分布を破線（Ｃ）で示す。このようにして修正さ
れた流速分布（Ｃ）及び（Ｂ）を流量算出器７ｂで次式
により流量が算出される。On the other hand, in the area of Xm away from the pipe wall, the influence of the noise is reduced, so that the normal flow velocity distribution (B)
Is detected. Therefore, with the flow velocity distribution display / corrector,
The flow velocity distribution (C) that is normally detected is made positive and extrapolated to the area Xn side to obtain the flow velocity distribution (C) by numerical analysis. The extrapolation is performed by approximating the flow velocity distribution (B) by, for example, a least-squares method using a second-order or third-order curve, and using the curve to obtain flow velocity data in the region Xn. The flow velocity distribution obtained by such extrapolation is shown by a broken line (C). The flow rates of the flow velocity distributions (C) and (B) thus corrected are calculated by the flow rate calculator 7b according to the following equation.
【００１１】[0011]
【数３】 (Equation 3)
【００１２】ここに、Ｖ（ｃ）：管壁近傍の修正した流
速，Ｖ（ｂ）：管壁近傍以外の検出された流速，Ｄ：流
路の直径，Ｂ（ｒ）：流路の測定距離Ｌと直角方向の幅
である。Here, V (c): corrected flow velocity near the pipe wall, V (b): detected flow velocity other than near the pipe wall, D: diameter of flow path, B (r): measurement of flow path The width in the direction perpendicular to the distance L.
【００１３】図２において流速分布曲線（Ｂ）と（Ｃ）
からなる曲線は、測定箇所の上流近傍の流路内に障害物
や急激な曲がりや合流管がなければ、通常、流路中心付
近の流速が最大で、管壁側に向かうに従い境界層が発達
するため流速は漸減する。従って、修正した流速分布曲
線は、横軸に測定対象の流路幅距離をとり縦軸には流速
をとるとき、上に凸な形状を示す。従って、第２の実施
例では、近似曲線が上に凸な形状とならない場合は、修
正曲線が適切でないので修正は誤りであるとの評価を流
量算出器に表示できるようにするものである。このよう
にすれば、不適切な修正を防止することが可能で、装置
の測定精度を向上させることができる。第３の実施例
は、図２において流速分布（Ａ）を無視する範囲Ｘｎ
を、図３に示すように超音波送受波器内２の発信素子面
２ａと送受波器の管壁に取り付ける面２ｂとの間の楔状
の充填材の材質長さＬｓ及び流路の壁の材質と厚さＬｐ
により実験的あるいは理論的に定められる距離Ｘｎに設
定して流速分布を修正する方法である。このようにすれ
ば、検出して得られた流速分布をモニタ画面にてその都
度検討する必要はなく、あらかじめ設定した距離Ｘｎの
範囲の検出された流速分布を自動的に修正するので、迅
速な測定が可能となる。In FIG. 2, the flow velocity distribution curves (B) and (C)
The curve consisting of indicates that the flow velocity near the center of the flow path is usually the maximum, and the boundary layer develops toward the pipe wall side, unless there are obstacles, sharp bends, and merge pipes in the flow path near the measurement point. The flow rate gradually decreases. Therefore, the corrected flow velocity distribution curve shows an upwardly convex shape when the horizontal axis represents the flow path width distance of the measurement target and the vertical axis represents the flow velocity. Therefore, in the second embodiment, when the approximate curve does not have an upwardly convex shape, the correction curve is not appropriate and the evaluation that the correction is erroneous can be displayed on the flow rate calculator. This makes it possible to prevent improper correction and improve the measurement accuracy of the device. In the third embodiment, the range Xn in which the flow velocity distribution (A) is ignored in FIG.
The material length Ls of the wedge-shaped filler between the transmitting element surface 2a in the ultrasonic transducer 2 and the surface 2b attached to the tube wall of the transducer as shown in FIG. Material and thickness Lp
Is a method of correcting the flow velocity distribution by setting the distance Xn to be experimentally or theoretically determined. With this configuration, it is not necessary to examine the flow velocity distribution obtained by the detection on the monitor screen each time, and the detected flow velocity distribution in the range of the preset distance Xn is automatically corrected. Measurement becomes possible.
【００１４】第４の実施例を図１と図２を使って説明す
る。図１の流速分布表示・修正器のモニタ画面には図２
に示す流速分布（Ａ）と（Ｂ）が当初表示される。次に
流速分布（Ａ）の修正を施す際、ノイズにより正しい流
速分布が得られていない範囲Ｘｎを目視により判断し、
修正を施す範囲Ｘｎをマニュアルにて設定するようにし
たものである。このようにすれば、より的確な修正範囲
を設定できるので、流量測定精度をより向上させること
ができる。測定部の最大流速が管路断面の中心からずれ
ていたり、流速が一定の箇所が広く存在する場合等、流
速分布が単純に上に凸な形状とならないような場合に、
本実施例の効果が大である。A fourth embodiment will be described with reference to FIGS. FIG. 2 shows the monitor screen of the flow velocity distribution display / corrector in FIG.
(A) and (B) are initially displayed. Next, when the flow velocity distribution (A) is corrected, a range Xn in which a correct flow velocity distribution is not obtained due to noise is visually determined,
The range Xn to be corrected is set manually. In this way, a more accurate correction range can be set, so that the flow rate measurement accuracy can be further improved. When the maximum flow velocity of the measuring part is deviated from the center of the pipe cross section, or when there is a wide range of locations where the flow velocity is constant, such as when the flow velocity distribution does not simply have a convex shape,
The effect of this embodiment is great.
【００１５】第５の実施例を図２を使って説明する。図
１の流速分布表示・修正器７ｂのモニタ画面は図２に示
すような流速分布が表示される。本実施例では検出され
た本来の分布曲線と外挿により修正して表示された分布
曲線の色や線の種類（実線や破線）を変えて表示し、修
正前後の曲線の相違を明瞭に認識できるようしたもので
ある。このようにすることにより、モニタでの修正作業
時のミス操作を防ぎ全体の測定精度向上に寄与できる。A fifth embodiment will be described with reference to FIG. The monitor screen of the flow velocity distribution display / corrector 7b in FIG. 1 displays a flow velocity distribution as shown in FIG. In the present embodiment, the original distribution curve detected and the distribution curve modified and displayed by extrapolation are displayed in a different color or line type (solid line or broken line), and the difference between the curves before and after modification is clearly recognized. What you can do. By doing so, it is possible to prevent an erroneous operation at the time of correction work on the monitor and contribute to improvement of the overall measurement accuracy.
【００１６】[0016]
【発明の効果】本発明によれば、パルスドップラ式超音
波流量計で比較的小径の流路の流量を測定するとき、本
質的に存在する送受波器の設置側の管壁付近の流速測定
精度の低下を補うことが可能で、その結果、流量測定精
度が向上する。According to the present invention, when measuring the flow rate of a flow path having a relatively small diameter with a pulse Doppler type ultrasonic flow meter, the flow velocity measurement near the tube wall on the installation side of the transducer which is essentially present is provided. It is possible to compensate for the decrease in accuracy, and as a result, the flow measurement accuracy is improved.
【図１】本発明の実施例の構成を示すブロック図であ
る。FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
【図２】検出された流速分布とその修正した速度分布を
示す図である。FIG. 2 is a diagram showing a detected flow velocity distribution and its corrected velocity distribution.
【図３】本発明の第３の実施例を示す送受波器を設置し
た管路の断面図である。FIG. 3 is a cross-sectional view of a pipe in which a transmitter / receiver according to a third embodiment of the present invention is installed.
【図４】従来技術のパルスドップラ式超音波流量計の原
理を説明する図である。FIG. 4 is a diagram illustrating the principle of a conventional pulse Doppler ultrasonic flowmeter.
【図５】従来技術の課題を説明するための超音波送受波
器の取付状況と検出された管内の流速分布を示す図であ
る。FIG. 5 is a diagram showing an installation state of an ultrasonic transducer and a detected flow velocity distribution in a pipe for explaining a problem of the related art.
１…測定流路（管）、２…超音波送受波器、３…バース
ト状超音波送信波、４…水中の粒子、５…散乱波に基づ
く受信波、６…パルスドップラ式超音波流速計、７…流
量算出装置。DESCRIPTION OF SYMBOLS 1 ... Measurement flow path (tube), 2 ... Ultrasonic transducer, 3 ... Burst ultrasonic transmission wave, 4 ... Particles in water, 5 ... Receiving wave based on scattered wave, 6 ... Pulse Doppler ultrasonic current meter , 7 ... Flow rate calculating device.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 古閑 誠明 茨城県土浦市神立町603番地 株式会社日 立製作所土浦工場内 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Koga 603, Kandate-cho, Tsuchiura-shi, Ibaraki Pref.
Claims (1)
検出した測定流路断面の流速分布から流量を算出する
際、超音波送受波器を設置した側の流路壁近傍の検出流
速データ（Ａ）は無視し、壁面近傍以外で検出された流
速分布データ（Ｂ）から上記流路壁側へ外挿して得られ
る流速分布データ（Ｃ）に置き換えて修正し、送受波器
側壁面近傍は上記修正流速分布を適用し、それ以外の断
面は送受波器で検出された流速分布データ（Ｂ）を適用
して流路断面の流速分布を構成し、その流速分布に基づ
いて流量を算出することを特徴とするパルスドップラ式
超音波流量計。1. A pulse Doppler ultrasonic flowmeter,
When calculating the flow rate from the detected flow velocity distribution of the cross section of the measurement flow path, the detected flow velocity data (A) near the flow path wall on the side where the ultrasonic transducer is installed is ignored, and the flow velocity distribution detected other than near the wall surface The data (B) is replaced with the flow velocity distribution data (C) obtained by extrapolating to the flow path wall side and corrected. The corrected flow velocity distribution is applied to the vicinity of the side wall of the transducer, and the other cross sections are transmitted and received. A pulse Doppler ultrasonic flowmeter characterized in that a flow velocity distribution in a cross section of a flow path is configured by applying flow velocity distribution data (B) detected by a vessel, and a flow rate is calculated based on the flow velocity distribution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9089088A JPH10281832A (en) | 1997-04-08 | 1997-04-08 | Pulse doppler type ultrasonic flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9089088A JPH10281832A (en) | 1997-04-08 | 1997-04-08 | Pulse doppler type ultrasonic flowmeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10281832A true JPH10281832A (en) | 1998-10-23 |
Family
ID=13961128
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9089088A Pending JPH10281832A (en) | 1997-04-08 | 1997-04-08 | Pulse doppler type ultrasonic flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10281832A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005064287A1 (en) * | 2003-12-26 | 2005-07-14 | The Tokyo Electric Power Company, Incorporated | Ultrasonic flow meter, flow measurement method, and computer program |
| WO2005083371A1 (en) * | 2004-02-27 | 2005-09-09 | Fuji Electric Systems Co., Ltd. | Doppler type ultrasonic flowmeter |
| JP2005351827A (en) * | 2004-06-14 | 2005-12-22 | Fuji Electric Systems Co Ltd | Wedge used for doppler ultrasound flowmeter, and wedge unit |
| JP2005351828A (en) * | 2004-06-14 | 2005-12-22 | Fuji Electric Systems Co Ltd | Wedge unit used for doppler ultrasound flowmeter |
| WO2006080182A1 (en) * | 2005-01-31 | 2006-08-03 | Fuji Electric Systems Co., Ltd. | Ultrasonic flowmeter and ultrasonic flowmeter employing two methods |
| US7437948B2 (en) | 2004-02-26 | 2008-10-21 | Fuji Electric Systems Co., Ltd. | Ultrasonic flowmeter and ultrasonic flow rate measurement method |
| JP2009198388A (en) * | 2008-02-22 | 2009-09-03 | Tokyo Electric Power Co Inc:The | Ultrasonic flowmeter |
-
1997
- 1997-04-08 JP JP9089088A patent/JPH10281832A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005064287A1 (en) * | 2003-12-26 | 2005-07-14 | The Tokyo Electric Power Company, Incorporated | Ultrasonic flow meter, flow measurement method, and computer program |
| US7437948B2 (en) | 2004-02-26 | 2008-10-21 | Fuji Electric Systems Co., Ltd. | Ultrasonic flowmeter and ultrasonic flow rate measurement method |
| WO2005083371A1 (en) * | 2004-02-27 | 2005-09-09 | Fuji Electric Systems Co., Ltd. | Doppler type ultrasonic flowmeter |
| JPWO2005083371A1 (en) * | 2004-02-27 | 2007-11-22 | 富士電機システムズ株式会社 | Doppler ultrasonic flow meter |
| JP4535065B2 (en) * | 2004-02-27 | 2010-09-01 | 富士電機システムズ株式会社 | Doppler ultrasonic flow meter |
| US7806003B2 (en) | 2004-02-27 | 2010-10-05 | Fuji Electric Systems Co., Ltd. | Doppler type ultrasonic flow meter |
| JP2005351827A (en) * | 2004-06-14 | 2005-12-22 | Fuji Electric Systems Co Ltd | Wedge used for doppler ultrasound flowmeter, and wedge unit |
| JP2005351828A (en) * | 2004-06-14 | 2005-12-22 | Fuji Electric Systems Co Ltd | Wedge unit used for doppler ultrasound flowmeter |
| WO2006080182A1 (en) * | 2005-01-31 | 2006-08-03 | Fuji Electric Systems Co., Ltd. | Ultrasonic flowmeter and ultrasonic flowmeter employing two methods |
| JPWO2006080182A1 (en) * | 2005-01-31 | 2008-08-07 | 富士電機システムズ株式会社 | Ultrasonic flow meter, 2-type combined ultrasonic flow meter |
| JP4548482B2 (en) * | 2005-01-31 | 2010-09-22 | 富士電機システムズ株式会社 | Ultrasonic flow meter, 2-type combined ultrasonic flow meter |
| JP2009198388A (en) * | 2008-02-22 | 2009-09-03 | Tokyo Electric Power Co Inc:The | Ultrasonic flowmeter |
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