JP3468233B2 - Flow measurement device - Google Patents

Flow measurement device

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Publication number
JP3468233B2
JP3468233B2 JP2001306114A JP2001306114A JP3468233B2 JP 3468233 B2 JP3468233 B2 JP 3468233B2 JP 2001306114 A JP2001306114 A JP 2001306114A JP 2001306114 A JP2001306114 A JP 2001306114A JP 3468233 B2 JP3468233 B2 JP 3468233B2
Authority
JP
Japan
Prior art keywords
reference voltage
flow rate
voltage
output
measuring device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2001306114A
Other languages
Japanese (ja)
Other versions
JP2003106882A (en
Inventor
修 江口
秀二 安倍
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Corp
Panasonic Holdings Corp
Original Assignee
Panasonic Corp
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Panasonic Corp, Matsushita Electric Industrial Co Ltd filed Critical Panasonic Corp
Priority to JP2001306114A priority Critical patent/JP3468233B2/en
Priority to TW92107299A priority patent/TWI259900B/en
Publication of JP2003106882A publication Critical patent/JP2003106882A/en
Application granted granted Critical
Publication of JP3468233B2 publication Critical patent/JP3468233B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は超音波を利用してガ
スなどの流量を計測する流量計測装置に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate measuring device for measuring the flow rate of gas or the like by utilizing ultrasonic waves.

【０００２】[0002]

【従来の技術】従来のこの種の流量計測装置は、図１８
に示すようなものが一般的であった。この装置は流体の
流れる流路１に設置した超音波振動子２と、第１超音波
振動子２、第２超音波振動子３の送受信を切り換える切
換手段４と、第１超音波振動子２及び第２超音波振動子
３を駆動する送信手段５と、受信側の超音波振動子で受
信した信号を所定の振幅まで増幅する増幅手段６と、増
幅手段６で増幅された受信信号と基準電圧とを比較する
基準比較手段７と、図１９に示すように基準比較手段７
で基準電圧と比較し大小関係が反転した後の増幅信号の
最初のゼロクロス点ａで繰り返し手段９へ出力信号Ｄを
出力する判定手段８と、この判定手段８からの信号をカ
ウントし予め設定された回数だけカウントすると共に判
定手段８からの信号を制御手段１２へ出力する繰り返し
手段９と、繰り返し手段９で予め設定された回数をカウ
ントした時間を計時する計時手段１０と、計時手段１０
の計時した時間に応じて管路の大きさや流れの状態を考
慮して流量を算出する流量算出手段１１と、流量算出手
段１１から算出された流量出力、繰り返し手段９からの
信号を受け送信手段５の動作を制御する制御手段１２と
から構成されている。2. Description of the Related Art A conventional flow rate measuring device of this type is shown in FIG.
Those shown in were common. This device includes an ultrasonic transducer 2 installed in a flow path 1 of a fluid, a switching means 4 for switching between transmission and reception of a first ultrasonic transducer 2 and a second ultrasonic transducer 3, and a first ultrasonic transducer 2 And a transmitting means 5 for driving the second ultrasonic transducer 3, an amplifying means 6 for amplifying a signal received by the ultrasonic transducer on the receiving side to a predetermined amplitude, and a received signal amplified by the amplifying means 6 and a reference. Reference comparing means 7 for comparing the voltage and reference comparing means 7 as shown in FIG.
At the first zero-cross point a of the amplified signal after being compared with the reference voltage and the magnitude relationship is inverted, the determining means 8 which outputs the output signal D to the repeating means 9 and the signal from the determining means 8 are counted and set in advance. The number of times, and the signal from the determination means 8 is output to the control means 12, the repeating means 9, the time counting means 10 for counting the number of times preset by the repeating means 9, and the time counting means 10.
The flow rate calculating means 11 for calculating the flow rate in consideration of the size of the pipeline and the flow state in accordance with the time measured by, the flow rate output calculated by the flow rate calculating means 11, the signal from the repeating means 9, and the transmitting means. 5 and the control means 12 for controlling the operation.

【０００３】この装置は制御手段１２により送信手段５
を動作させ超音波振動子２で発信された超音波信号が、
流れの中を伝搬し第２超音波振動子３で受信され、増幅
手段６で増幅後、基準比較手段７と判定手段８で信号処
理され、繰り返し手段９を通り制御手段１２に入力され
る。この動作を予め設定されたｎ回数繰り返し行い、こ
の間の時間を計時手段１０により測定する。In this device, the control means 12 controls the transmission means 5
The ultrasonic signal transmitted by the ultrasonic transducer 2
The signal is propagated in the flow, received by the second ultrasonic transducer 3, amplified by the amplifying means 6, processed by the reference comparing means 7 and the judging means 8, and input to the control means 12 through the repeating means 9. This operation is repeated n times set in advance, and the time interval is measured by the time measuring means 10.

【０００４】そして、第１超音波振動子２と第２超音波
振動子３とを切換手段４により切り替えて、同様な動作
を行い、被測定流体の上流から下流（この方向を正流と
する）と下流から上流（この方向を逆流とする）のそれ
ぞれの伝搬時間を測定し、（式１）より流量Ｑを求めて
いた（超音波振動子間の流れ方向の有効距離をＬ、上流
から下流へのｎ回分の測定時間をｔ１、下流から上流へ
のｎ回分の測定時間をｔ２、被測定流体の流速をｖ、流
路の断面積をＳ、センサ角度をφ、流量をＱとする）。Then, the first ultrasonic transducer 2 and the second ultrasonic transducer 3 are switched by the switching means 4 to perform the same operation, and the fluid to be measured is changed from upstream to downstream (this direction is a forward flow). ) And downstream to upstream (this direction is referred to as backflow), and the flow rate Q was obtained from (Equation 1) (effective distance in the flow direction between ultrasonic transducers was L, from upstream) The measurement time for n times downstream is t1, the measurement time for n times downstream to upstream is t2, the flow velocity of the fluid to be measured is v, the cross-sectional area of the flow path is S, the sensor angle is φ, and the flow rate is Q. ).

【０００５】Ｑ＝Ｓ・ｖ＝Ｓ・Ｌ／２・ｃｏｓφ（（１
／ｔ１）−（１／ｔ２））・・・（式１）（実際には、
式１に流量に応じた係数を乗じて流量を算出する）ま
た、増幅手段６のゲインは受信側の超音波振動子で受信
した信号を一定振幅となるようゲインを調整しており、
流量計測毎に受信信号のピーク電圧値が所定の電圧範囲
に入るように調整される。これは図２０の点線で示す受
信信号ｂに示すように受信信号のピーク電圧値が所定の
電圧範囲の下限より下回った時は、次回の流量計測時に
ゲインがアップされ、また、図２０の点線で示す受信信
号ｃに示すように受信信号のピーク電圧値が所定の電圧
範囲の上限より上回った時は、次回の流量計測時にゲイ
ンをダウンして図２０の実線で示す受信信号ａのように
電圧範囲の上限、下限の内に入るようにする。この動作
は流量計測毎に行われる。Q = S · v = S · L / 2 · cos φ ((1
/ T1)-(1 / t2)) (Equation 1) (actually,
The flow rate is calculated by multiplying Equation 1 by a coefficient according to the flow rate. Further, the gain of the amplification means 6 is adjusted so that the signal received by the ultrasonic transducer on the receiving side has a constant amplitude,
The peak voltage value of the received signal is adjusted so as to fall within a predetermined voltage range for each flow rate measurement. This is because when the peak voltage value of the received signal is below the lower limit of the predetermined voltage range as shown by the received signal b shown by the dotted line in FIG. 20, the gain is increased at the next flow rate measurement, and the dotted line in FIG. When the peak voltage value of the received signal is higher than the upper limit of the predetermined voltage range as shown by the received signal c, the gain is reduced at the next flow rate measurement and the received signal a is shown by the solid line in FIG. Make sure that it falls within the upper and lower limits of the voltage range. This operation is performed for each flow rate measurement.

【０００６】[0006]

【発明が解決しようとする課題】しかしながら上記従来
の流量計測装置は、基準比較手段において所定の振幅レ
ベルに増幅された受信信号と比較する基準電圧の電圧設
定方法として、固定抵抗器と半固定抵抗器を用い抵抗分
圧で設定することが多く用いられてきた。この方法では
所定の電圧を発生するように基準電圧を監視しながら半
固定抵抗器を手動で調節を行うので基準電圧設定に時間
が掛かり、また、調整ミスの発生の可能性も有してい
た。However, the above-mentioned conventional flow rate measuring device uses a fixed resistor and a semi-fixed resistor as a voltage setting method of the reference voltage to be compared with the received signal amplified to a predetermined amplitude level by the reference comparison means. It has been often used to set the voltage by resistance partial pressure using a pressure vessel. In this method, the semi-fixed resistor is manually adjusted while monitoring the reference voltage so as to generate a predetermined voltage, so it takes time to set the reference voltage, and there is a possibility that an adjustment error may occur. .

【０００７】さらに調整後の経年変化、また、機械振
動、熱衝撃等を受けることによって調整位置が変化した
りすることもあった。そして超音波振動子が経年変化等
でその感度が変化すると再度、基準電圧を設定し直す必
要があるという課題を有していた。本発明は、前記従来
の課題を解決するもので、基準電圧の設定を迅速かつ、
精度良く行い、常に最適な基準電圧に保つ流量計測装置
を提供することを目的とする。Further, the adjustment position may change due to secular change after adjustment, or mechanical vibration, thermal shock or the like. Then, when the sensitivity of the ultrasonic transducer changes due to aging or the like, there is a problem that the reference voltage needs to be set again. The present invention is to solve the above-mentioned conventional problems, and to set the reference voltage quickly and
It is an object of the present invention to provide a flow rate measuring device that is accurately performed and always maintains an optimum reference voltage.

【０００８】[0008]

【課題を解決するための手段】前記従来の課題を解決す
るために、本発明の流量計測装置は超音波振動子の受信
信号を基に電圧設定手段が適当な基準電圧を出力するよ
うにしたものである。In order to solve the above-mentioned conventional problems, in the flow rate measuring device of the present invention, the voltage setting means outputs an appropriate reference voltage based on the reception signal of the ultrasonic transducer. It is a thing.

【０００９】これによって基準電圧は人手を介すること
なく、常に受信信号に対し所定の電圧を出力することが
可能となるので、基準電圧の設定動作が迅速かつ、精度
良く行われ、常に最適な基準電圧に保たれた流量計測装
置となる。As a result, the reference voltage can always output a predetermined voltage with respect to the received signal without human intervention, so that the reference voltage setting operation can be performed quickly and accurately, and an optimum reference voltage can always be obtained. It becomes a flow rate measuring device kept at voltage.

【００１０】[0010]

【発明の実施の形態】本発明の請求項１に記載の発明
は、流体管路に設けられ超音波信号を送受信する第１振
動子及び第２振動子と、前記振動子を駆動する送信手段
と、前記振動子の送受信を切り換える切換手段と、前記
振動子間の相互の超音波伝達を複数回行う繰り返し手段
と、超音波伝搬の累積時間に基づいて流量を算出する流
量算出手段と、受信側の振動子の受信信号を増幅する増
幅手段と、基準電圧を出力する電圧設定手段と、前記増
幅手段で増幅された信号と基準電圧とを比較する基準比
較手段と、前記基準比較手段の出力と前記増幅手段出力
とから超音波の到達ポイントを判定する判定手段とを備
え、前記電圧設定手段は、超音波の伝搬時間に基づいて
基準電圧を設定することにより、電圧設定部が基準電圧
の設定可能範囲を認識し、設定可能範囲で電圧設定部が
基準電圧を出力し、基準電圧の設定動作が迅速かつ、精
度良く行われ、常に最適な基準電圧に保たれた流量計測
装置とすることが出来る。BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is a first oscillator and a second oscillator provided in a fluid conduit for transmitting and receiving ultrasonic signals, and transmitting means for driving the oscillator. A switching means for switching between transmission and reception of the vibrator, a repeating means for performing mutual ultrasonic transmission between the vibrators a plurality of times, a flow rate calculation means for calculating a flow rate based on the cumulative time of ultrasonic wave propagation, and a reception means. Amplifying means for amplifying a received signal of the vibrator on the side, voltage setting means for outputting a reference voltage, reference comparing means for comparing the signal amplified by the amplifying means with the reference voltage, and output of the reference comparing means. And a determination means for determining the arrival point of the ultrasonic wave from the amplification means output, the voltage setting means, by setting the reference voltage based on the propagation time of the ultrasonic wave, the voltage setting unit of the reference voltage Confirm the settable range And outputs the reference voltage the voltage setting unit in setting range, the setting operation of the reference voltage and quickly carried out accurately, always kept optimum reference voltage flow rate measuring device that it is possible.

【００１１】請求項２に記載の発明は、流体管路に設け
られ超音波信号を送受信する第１振動子及び第２振動子
と、前記振動子を駆動する送信手段と、前記振動子の送
受信を切り換える切換手段と、前記振動子間の相互の超
音波伝達を複数回行う繰り返し手段と、超音波伝搬の累
積時間に基づいて流量を算出する流量算出手段と、受信
側の振動子の受信信号を増幅する増幅手段と、基準電圧
を出力する電圧設定手段と、前記増幅手段で増幅された
信号と基準電圧とを比較する基準比較手段と、前記基準
比較手段の出力と前記増幅手段出力とから超音波の到達
ポイントを判定する判定手段とを備え、前記電圧設定手
段は、前記基準比較手段の出力と前記判定手段からの出
力の時間差に基づいて基準電圧を設定する流量計測装置
とすることにより、増幅手段により所定の振幅まで増幅
された受信側の振動子の受信信号が基準電圧を越えてか
ら、判定手段により検知される受信信号のゼロクロスポ
イントまでの時間を計時し、この時間差より電圧設定部
が基準電圧の設定可能範囲を認識し、設定可能範囲で電
圧設定部が基準電圧を設定するので、受信信号に対して
基準電圧を設定することが出来、基準電圧の設定が迅速
かつ、精度良く行われ、常に最適な基準電圧に保たれた
流量計測装置とすることが出来る。According to a second aspect of the present invention, there are provided a first oscillator and a second oscillator provided in the fluid conduit for transmitting and receiving ultrasonic signals, transmitting means for driving the oscillator, and transmitting and receiving the oscillator. Switching means for switching between the transducers, repeating means for mutually transmitting ultrasonic waves between the transducers a plurality of times, flow rate calculating means for calculating the flow rate based on the cumulative time of ultrasonic wave propagation, and reception signals of the transducers on the receiving side. Amplifying means for amplifying, a voltage setting means for outputting a reference voltage, a reference comparing means for comparing the signal amplified by the amplifying means with a reference voltage, an output of the reference comparing means and an output of the amplifying means. By providing a flow rate measuring device that includes a determining unit that determines an ultrasonic wave reaching point, and the voltage setting unit sets a reference voltage based on a time difference between the output of the reference comparing unit and the output from the determining unit. The time from the reception signal of the transducer on the receiving side amplified to a predetermined amplitude by the amplification means exceeding the reference voltage to the zero cross point of the reception signal detected by the determination means is measured, and the voltage setting unit is calculated from this time difference. Recognizes the settable range of the reference voltage, and the voltage setting unit sets the reference voltage within the settable range, so the reference voltage can be set for the received signal, and the reference voltage can be set quickly and accurately. Therefore, the flow rate measuring device can be always maintained at the optimum reference voltage.

【００１２】請求項３に記載の発明は、電圧設定手段
が、増幅手段の出力のピーク電圧に対し所定の比率の基
準電圧を出力する請求項１または２記載の流量計測装置
とすることにより、増幅手段により所定の振幅まで増幅
された受信側の振動子の受信信号に対し、予め設定され
た比率の基準電圧を電圧設定手段で出力するので、受信
信号に対してほぼ一定の比率の基準電圧とすることが出
来、基準電圧の設定が迅速かつ、精度良く行われ、常に
最適な基準電圧に保たれた流量計測装置とすることが出
来る。According to a third aspect of the present invention, the voltage setting means outputs the reference voltage having a predetermined ratio with respect to the peak voltage of the output of the amplifying means. The reference voltage having a preset ratio is output by the voltage setting device to the reception signal of the transducer on the reception side that has been amplified to a predetermined amplitude by the amplification device, so that the reference voltage has a substantially constant ratio to the reception signal. The reference voltage can be set quickly and accurately, and the flow rate measuring device can be always kept at the optimum reference voltage.

【００１３】請求項４に記載の発明は、電圧設定手段
が、基準電圧の電圧設定範囲の上限，下限基準電圧にお
ける時間差の中間点となる時間差である基準電圧を設定
する請求項２記載の流量計測装置とすることにより、増
幅手段により所定の振幅まで増幅された受信側の振動子
の受信信号が基準電圧を越えてから、判定手段により検
知される受信信号のゼロクロスポイントまでの時間を計
時し、この時間差より電圧設定部が基準電圧の設定可能
範囲を認識し、設定可能範囲の中間点で電圧設定部が基
準電圧を設定するので、受信信号に対して特定のポイン
トに基準電圧を設定することが出来、基準電圧の設定が
迅速かつ、精度良く行われ、常に最適な基準電圧に保た
れた流量計測装置とすることが出来る。According to a fourth aspect of the invention, the voltage setting means sets the reference voltage which is a time difference which is an intermediate point of time differences between the upper limit and the lower limit reference voltage of the voltage setting range of the reference voltage. By using the measuring device, the time from the reception signal of the transducer on the reception side amplified to a predetermined amplitude by the amplification means exceeding the reference voltage to the zero cross point of the reception signal detected by the determination means is measured. The voltage setting unit recognizes the settable range of the reference voltage based on this time difference, and the voltage setting unit sets the reference voltage at the midpoint of the settable range, so the reference voltage is set to a specific point for the received signal. Therefore, the flow rate measuring device can be set in which the reference voltage is set quickly and accurately, and the reference voltage is always kept at the optimum value.

【００１４】請求項５に記載の発明は、電圧設定手段
が、基準比較手段の出力信号のパルス幅に基づいて基準
電圧の設定動作を行う請求項１または２記載の流量計測
装置とすることにより、増幅手段により所定の振幅まで
増幅された受信側の振動子の受信信号が基準電圧を越え
ている期間の時間を計時し、この時間が所定の時間とな
るように電圧設定部で基準電圧を設定するので、受信信
号に対して特定のポイントに基準電圧を設定することが
出来、基準電圧の設定が迅速かつ、精度良く行われ、常
に最適な基準電圧に保たれた流量計測装置とすることが
出来る。According to a fifth aspect of the present invention, the voltage setting means performs the setting operation of the reference voltage based on the pulse width of the output signal of the reference comparison means. , A time period during which the reception signal of the receiving-side transducer amplified to a predetermined amplitude by the amplification means exceeds the reference voltage, and the reference voltage is set by the voltage setting unit so that this time becomes the predetermined time. Since it is set, the reference voltage can be set at a specific point with respect to the received signal, the reference voltage can be set quickly and accurately, and the flow rate measurement device should always be kept at the optimum reference voltage. Can be done.

【００１５】請求項６に記載の発明は、電圧設定手段
が、記憶部が初期化直後または定期的な更新時期である
場合に、基準電圧の設定動作を行う請求項１または２記
載の流量計測装置とすることにより、記憶部に記憶され
ている電圧設定部の設定で基準電圧を出力するので設定
動作が迅速かつ、精度良く行われ、常に最適な基準電圧
に保たれた流量計測装置とすることが出来る。According to a sixth aspect of the present invention, the flow rate measurement means according to the first or second aspect, in which the voltage setting means performs the reference voltage setting operation immediately after the storage unit is initialized or when the storage unit is periodically updated. By using the device, the reference voltage is output according to the setting of the voltage setting unit stored in the storage unit, so that the setting operation is performed quickly and accurately, and the flow rate measuring device is always kept at the optimum reference voltage. You can

【００１６】請求項７に記載の発明は、電圧設定手段
が、増幅手段のゲインが変更されていれば基準電圧の設
定動作を行う請求項１または２記載の流量計測装置とす
ることにより、増幅手段のゲインが変更されたことによ
り増幅手段により増幅された受信信号と基準電圧の相対
関係が変化したときのみ電圧設定部の基準電圧値の更新
を行い、基準電圧の設定が迅速かつ、精度良く行われ、
常に最適な基準電圧に保たれた流量計測装置とすること
が出来る。According to a seventh aspect of the present invention, the voltage setting means performs the setting operation of the reference voltage if the gain of the amplifying means is changed. The reference voltage value of the voltage setting section is updated only when the relative relationship between the received signal amplified by the amplifying means and the reference voltage changes due to the change of the gain of the means, so that the reference voltage can be set quickly and accurately. Done,
The flow rate measuring device can always be kept at the optimum reference voltage.

【００１７】請求項８に記載の発明は、電圧設定手段
が、流量算出手段により算出した流量の変化に応じて基
準電圧を更新する請求項１または２記載の流量計測装置
とすることにより、流量が変化し超音波振動子の感度が
変化することで、増幅手段のゲインが変化した場合電圧
設定部の基準電圧値の更新を行い、基準電圧の設定が迅
速かつ、精度良く行われ、常に最適な基準電圧に保たれ
た流量計測装置とすることが出来る。According to an eighth aspect of the present invention, the voltage setting means updates the reference voltage in accordance with a change in the flow rate calculated by the flow rate calculating means. When the gain of the amplification means changes due to the change in the sensitivity of the ultrasonic transducer and the change in the sensitivity of the ultrasonic transducer, the reference voltage value of the voltage setting section is updated, and the reference voltage is set quickly and accurately, and is always optimized. The flow rate measuring device can be maintained at a different reference voltage.

【００１８】請求項９に記載の発明は、流体の温度を算
出する温度算出部を備え、電圧設定手段が、流体の温度
が一定以上変化するごとに基準電圧の設定動作を行う請
求項１または２記載の流量計測装置とすることにより、
流体の温度が変化し超音波振動子の感度が変化すること
で、増幅手段のゲインが変化した場合のみ電圧設定部の
基準電圧値の更新を行い、基準電圧の設定が迅速かつ、
精度良く行われ、常に最適な基準電圧に保たれた流量計
測装置とすることが出来る。According to a ninth aspect of the present invention, there is provided a temperature calculating section for calculating the temperature of the fluid, and the voltage setting means performs the reference voltage setting operation each time the temperature of the fluid changes by a certain amount or more. By using the flow rate measuring device described in 2,
By changing the temperature of the fluid and changing the sensitivity of the ultrasonic transducer, the reference voltage value of the voltage setting section is updated only when the gain of the amplifying means changes, and the setting of the reference voltage is quick and
It is possible to obtain a flow rate measuring device that is accurately performed and is always kept at an optimum reference voltage.

【００１９】請求項１０に記載の発明は、流体管路に設
けられ超音波信号を送受信する第１振動子及び第２振動
子を送信手段で駆動し、受信側の振動子の受信信号を増
幅手段で増幅し、電圧設定手段が基準電圧を出力して、
前記増幅手段で増幅された信号と基準電圧とを基準比較
手段が比較し、前記基準比較手段の出力と前記増幅手段
出力とから判定手段が超音波の到達ポイントを判定する
流量計測方法において、前記電圧設定手段は、増幅手段
の出力のピーク電圧に対し所定の比率の基準電圧を出力
して、前記基準比較手段の出力と前記判定手段からの出
力との時間差または超音波の伝搬時間に基づいて基準電
圧を設定する流量計測方法により、増幅手段により所定
の振幅まで増幅された受信側の振動子の受信信号に対
し、予め設定された比率の基準電圧を電圧設定手段で出
力するので、受信信号に対してほぼ一定の比率の基準電
圧とすることが出来、基準電圧の設定が迅速かつ、精度
良く行われ、常に最適な基準電圧に保つことが出来る。According to a tenth aspect of the present invention, the first oscillator and the second oscillator provided in the fluid conduit for transmitting and receiving ultrasonic signals are driven by the transmitting means, and the reception signal of the receiving oscillator is amplified. Amplify by the means, the voltage setting means outputs the reference voltage,
In the flow rate measurement method, the reference comparison unit compares the signal amplified by the amplification unit with a reference voltage, and the determination unit determines the arrival point of the ultrasonic wave from the output of the reference comparison unit and the output of the amplification unit. The voltage setting means outputs a reference voltage of a predetermined ratio with respect to the peak voltage of the output of the amplifying means, and based on the time difference between the output of the reference comparing means and the output of the judging means or the propagation time of ultrasonic waves. With the flow rate measuring method of setting the reference voltage, the voltage setting means outputs the reference voltage of a preset ratio to the reception signal of the transducer on the receiving side amplified to a predetermined amplitude by the amplification means. However, the reference voltage can be set to a substantially constant ratio, the reference voltage can be set quickly and accurately, and the reference voltage can always be kept at the optimum value.

【００２０】[0020]

【実施例】以下本発明の実施例について図面を参照しな
がら説明する。Embodiments of the present invention will be described below with reference to the drawings.

【００２１】（実施例１） 図１は本発明の実施例１における流量計測装置のブロッ
ク図を示すものである。(Embodiment 1) FIG. 1 is a block diagram of a flow rate measuring apparatus in Embodiment 1 of the present invention.

【００２２】図２は本発明の実施例１の流量計測装置の
動作説明図である。図１において、流路１の途中に超音
波を送信する第１超音波振動子２と受信する第２超音波
振動子３が流れ方向に角度φで配置されている。５は第
１超音波振動子２への送信手段であり、４は第１超音波
振動子２、第２超音波振動子３の送受信を切り換える切
換手段、６は受信側の超音波振動子で受信した信号を一
定振幅となるようゲインを調整し増幅する増幅手段、１
３は前記増幅手段６の出力を基に予め設定された基準電
圧を基準比較手段へ出力する電圧設定手段、７は前記増
幅手段６で増幅された信号と基準電圧とを比較する基準
比較手段、８は基準比較手段７の出力と前記増幅手段６
で増幅された信号とから超音波の到達ポイントを判定す
る判定手段、９は判定手段８の信号をカウントし予め設
定された回数だけカウントすると共に判定手段８からの
信号を制御手段１２へ出力する繰り返し手段である。１
０は繰り返し手段９で予め設定された回数をカウントし
た時間を計時する計時手段であり、１１は第１計時手段
１０の計時した時間に応じて管路の大きさや流れの状態
を考慮して流量を算出する流量算出手段である。また、
１２は流量算出手段１１、繰り返し手段９からの信号を
受け送信手段５、増幅手段６の動作を制御する制御手段
である。FIG. 2 is a diagram for explaining the operation of the flow rate measuring device according to the first embodiment of the present invention. In FIG. 1, a first ultrasonic transducer 2 that transmits ultrasonic waves and a second ultrasonic transducer 3 that receives ultrasonic waves are arranged in the flow path 1 at an angle φ in the flow direction. Reference numeral 5 is a transmitting means to the first ultrasonic transducer 2, 4 is a switching means for switching the transmission and reception of the first ultrasonic transducer 2 and the second ultrasonic transducer 3, and 6 is an ultrasonic transducer on the receiving side. Amplifying means for adjusting the gain of the received signal so as to have a constant amplitude and amplifying the gain.
3 is a voltage setting means for outputting a reference voltage preset based on the output of the amplifying means 6 to the reference comparing means, 7 is a reference comparing means for comparing the signal amplified by the amplifying means 6 with the reference voltage, 8 is the output of the reference comparison means 7 and the amplification means 6
Judgment means for judging the arrival point of the ultrasonic wave from the signal amplified by 9 and 9 counts the signal of the judgment means 8 and counts a preset number of times and outputs the signal from the judgment means 8 to the control means 12. It is a means of repetition. 1
Reference numeral 0 is a time measuring means for measuring the time when the number of times set in advance by the repeating means 9 is counted, and 11 is a flow rate in consideration of the size of the pipeline and the flow state according to the time measured by the first time measuring means 10. Is a flow rate calculating means for calculating. Also,
Reference numeral 12 is a control means for receiving the signals from the flow rate calculating means 11 and the repeating means 9 and controlling the operations of the transmitting means 5 and the amplifying means 6.

【００２３】以上のように構成された流量計測装置につ
いて、以下その動作、作用を説明する。まず制御手段１
２は流量計測を開始すると送信手段５を動作させ超音波
振動子２より超音波信号を送信する。第１超音波振動子
２より送信された超音波信号は流路１の流れの中を伝搬
し、第２超音波振動子３で受信され、増幅手段６で制御
手段１２からの指示により、受信信号が一定の振幅にな
るようなゲインに自動的に調整されて、基準比較手段
７、電圧設定手段１３、判定手段８へ出力される。電圧
設定手段１３は増幅手段６の出力のピーク電圧に対し所
定の比率の電圧を発生し、基準比較手段７へ出力する。
ここで図２に受信波の様子、さらに（表１）に受信波の
２波、３波の波高値と受信波のピーク値となる５波の波
高値との比率を示す（流体は１３Ａの場合）。The operation and action of the flow rate measuring device constructed as above will be described below. First, the control means 1
When the flow rate measurement 2 starts, the transmitting means 5 is operated to transmit the ultrasonic signal from the ultrasonic transducer 2. The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the flow path 1, is received by the second ultrasonic transducer 3, and is received by the amplifying means 6 according to an instruction from the control means 12. The signal is automatically adjusted to a gain so that the signal has a constant amplitude, and is output to the reference comparison unit 7, the voltage setting unit 13, and the determination unit 8. The voltage setting means 13 generates a voltage having a predetermined ratio with respect to the peak voltage of the output of the amplifying means 6, and outputs it to the reference comparing means 7.
Here, FIG. 2 shows the state of the received waves, and (Table 1) shows the ratios of the crest values of the received waves 2 and 3 and the crest values of the five waves which are the peak values of the received waves (fluid of 13 A If).

【００２４】[0024]

【表１】 [Table 1]

【００２５】（表１）に示すように２波、３波の波高値
と５波の波高値（ピーク値）との比率は温度にあまり影
響されず、ほぼ一定で２波／５波で０．７７、３波／５
波で０．８６程である。つまり図２に示すように２波と
３波の波高値の中間で基準電圧を設定しようとすると設
定電圧を５波の波高値（ピーク値）の０．８２程の比率
の電圧に設定すれば良い。このように電圧設定手段１３
は増幅手段６により所定の振幅になるように増幅された
受信信号をＡＤコンバータ等を用いて入力し、そのピー
ク値の０．８２程度の比率の電圧にＤＡコンバータ等を
用いて設定し、基準比較手段７へ出力する。基準比較手
段７は増幅手段６の出力と基準電圧とを比較し、図２に
示すようにその大小関係が反転した時点（タイミング
ｃ）で判定手段８に出力信号Ｃを出力する。判定手段８
ではタイミングｃ以降の増幅手段６出力の符号が正から
負に変わる最初の負のゼロクロス点ａを超音波の到達ポ
イントと判定し、出力信号Ｄを繰り返し手段９に出力す
る。As shown in (Table 1), the ratio of the peak value of 2 waves, 3 waves and the peak value of 5 waves (peak value) is not so much influenced by the temperature and is almost constant and is 0 for 2 waves / 5 waves. .77, 3 waves / 5
It's about 0.86 in waves. That is, as shown in FIG. 2, if it is attempted to set the reference voltage in the middle of the crest values of the two waves and the three waves, if the set voltage is set to a voltage having a ratio of the crest value (peak value) of the five waves of about 0.82. good. In this way, the voltage setting means 13
Is input by using an AD converter or the like, the received signal amplified to have a predetermined amplitude by the amplifying means 6, and is set by a DA converter or the like to a voltage having a ratio of about 0.82 of its peak value. Output to the comparison means 7. The reference comparison means 7 compares the output of the amplification means 6 with the reference voltage, and outputs the output signal C to the determination means 8 at the time point (timing c) when the magnitude relationship is inverted as shown in FIG. Judgment means 8
Then, the first negative zero-cross point a at which the sign of the output of the amplifying means 6 after the timing c changes from positive to negative is determined as the arrival point of the ultrasonic wave, and the output signal D is output to the repeating means 9.

【００２６】この判定手段８の出力信号Ｄは繰り返し手
段９でカウントされた後、制御手段１２に入力される。
制御手段１２は送信手段５を再度動作させ超音波振動子
２より超音波信号を送信すると共に第２計時手段１３ａ
に計時開始信号を再度出力し、この一連の動作を予め設
定されたｎ回数繰り返し行い、この間の時間を計時手段
１０により測定する。そして、第１超音波振動子２と第
２超音波振動子３とを切換手段４により切り替えて、同
様な動作を行い、被測定流体の上流から下流と下流から
上流のそれぞれの伝搬時間を測定し、これらの時間差よ
り流量算出手段１１で流路の大きさや流れの状態を考慮
して流量値を求める。以上のように動作することにより
基準電圧が電圧設定手段１３により増幅手段６の出力の
ピーク電圧に対し所定の比率の電圧に自動的に設定さ
れ、基準電圧の設定動作が迅速かつ、精度良く行われ、
常に最適な基準電圧に保たれた流量計測装置とすること
が出来る。The output signal D of the judging means 8 is counted by the repeating means 9 and then input to the control means 12.
The control means 12 operates the transmitting means 5 again to transmit the ultrasonic signal from the ultrasonic transducer 2 and at the same time, the second timing means 13a.
Then, the timing start signal is output again, this series of operations is repeated n times, which is set in advance, and the time interval 10 is measured by the timing means 10. Then, the first ultrasonic transducer 2 and the second ultrasonic transducer 3 are switched by the switching means 4 and the same operation is performed to measure the respective propagation times of the fluid to be measured from upstream to downstream and from downstream to upstream. Then, based on these time differences, the flow rate calculation means 11 determines the flow rate value in consideration of the size of the flow path and the flow state. By operating as described above, the reference voltage is automatically set by the voltage setting means 13 to a voltage having a predetermined ratio to the peak voltage of the output of the amplifying means 6, and the reference voltage setting operation is performed quickly and accurately. I,
The flow rate measuring device can always be kept at the optimum reference voltage.

【００２７】（実施例２） 図３は本発明の実施例２の流量計測装置のブロック図で
あり、図４は同流量計測装置の動作説明図である。図３
において、１３ｂは制御手段１２からの超音波の送信開
始信号と判定手段８からの出力より流体管路の超音波の
伝搬時間を計時する伝搬計時部であり、１３ａは前記伝
搬計時部１３ｂの出力より基準電圧を設定し基準比較手
段７へ出力する電圧設定部であり、伝搬計時部１３ａと
電圧設定部１３ｂで電圧設定手段１３を構成している。
他の構成要素は実施例１と同じであるので説明は省略す
る。(Second Embodiment) FIG. 3 is a block diagram of a flow rate measuring device according to a second embodiment of the present invention, and FIG. 4 is an operation explanatory diagram of the flow rate measuring device. Figure 3
In the above, 13b is a propagation time measuring unit that measures the propagation time of the ultrasonic wave in the fluid conduit from the ultrasonic transmission start signal from the control unit 12 and the output from the judging unit 8, and 13a is the output of the propagation time measuring unit 13b. Is a voltage setting unit for setting a reference voltage more and outputting the reference voltage to the reference comparing unit 7 and the propagation time measuring unit 13a.
The voltage setting unit 13b constitutes the voltage setting means 13.
The other components are the same as those in the first embodiment, and the description thereof will be omitted.

【００２８】以上のように構成された流量計測装置につ
いて、以下その動作、作用を説明する。制御手段１２は
流量計測を開始すると送信手段５を動作させ超音波振動
子２より超音波信号を送信する。第１超音波振動子２よ
り送信された超音波信号は流路１の流れの中を伝搬し、
第２超音波振動子３で受信され、増幅手段６で制御手段
１２からの指示により、受信信号が一定の振幅になるよ
うなゲインに自動的に調整されて、基準比較手段７、判
定手段８へ出力される。The operation and action of the flow rate measuring device constructed as above will be described below. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the ultrasonic transducer 2. The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1,
The gain is received by the second ultrasonic transducer 3, and the amplifying means 6 is automatically adjusted to a gain such that the received signal has a constant amplitude according to an instruction from the control means 12, and the reference comparing means 7 and the judging means 8 are provided. Is output to.

【００２９】電圧設定部１３ａは伝搬計時部１３ｂが制
御手段１２からの超音波の送信開始信号と判定手段８か
らの出力より計時する流体管路の超音波の伝搬時間を入
力しながら基準電圧を一旦、僅かずつ下げていき図４の
基準電圧ｂに示す判定手段８が受信波の２波のゼロクロ
ス点を検知するレベルまで下げると基準比較手段７の出
力と判定手段８の出力はそれぞれ出力信号Ｂ１、出力信
号Ｂ２となり、これにより判定手段８が３波のゼロクロ
ス点を検知していたときに比べ、伝搬計時部１３ｂが計
時する伝搬時間は超音波の駆動周波数の１波長分（５０
０ＫＨｚ：２μｓ）短くなる。The voltage setting unit 13a inputs a reference voltage while the propagation time measuring unit 13b inputs the ultrasonic wave propagation time of the fluid pipe measured by the ultrasonic wave transmission start signal from the control means 12 and the output from the judging means 8. Once the voltage is lowered little by little and the judgment means 8 shown by the reference voltage b in FIG. 4 is lowered to the level at which the zero crossing point of two waves of the received wave is detected, the output of the reference comparison means 7 and the output of the judgment means 8 are output signals. B1 becomes the output signal B2, and as a result, the propagation time measured by the propagation time measuring unit 13b is one wavelength (50 wavelengths) of the ultrasonic drive frequency, compared to when the determination unit 8 detects the three-wave zero-cross points.
0 KHz: 2 μs) shorter.

【００３０】そして、このように伝搬時間が超音波の駆
動周波数の１波長分短くなると電圧設定部１３ａは、逆
に基準電圧を僅かずつ上げていき、図４の基準電圧ｃに
示す受信波の４波のゼロクロス点を検知するレベルまで
上げると、基準比較手段７と判定手段８の出力がそれぞ
れ出力信号Ｃ１、出力信号Ｃ２となり伝搬計時部１３ｂ
が計時する伝搬時間が、最初の伝搬時間より超音波の駆
動周波数の１波長分まで長くなる。When the propagation time is shortened by one wavelength of the driving frequency of the ultrasonic wave in this way, the voltage setting section 13a, on the contrary, raises the reference voltage little by little, and the received wave shown by the reference voltage c in FIG. When the level is raised to the level at which the zero-cross points of the four waves are detected, the outputs of the reference comparison unit 7 and the determination unit 8 become the output signal C1 and the output signal C2, respectively, and the propagation time measuring unit 13b.
The propagation time measured by is longer than the initial propagation time by one wavelength of the ultrasonic drive frequency.

【００３１】このように基準電圧を変化させていくと図
４に示すように基準電圧は受信波の２波のＭａｘ値付近
から、３波のＭａｘ値付近まで変化するので、電圧設定
部１３ａはその中間点を最適な基準電圧として決定し、
基準比較手段７へ出力する。そして、基準比較手段７は
この決定された基準電圧と増幅手段６の出力とを比較
し、その大小関係が反転した時点を判定手段８に通知
し、判定手段８ではそれ以降の増幅手段６出力の符号が
正から負に変わる最初の負のゼロクロス点（図４のゼロ
クロス点ａ）を超音波の到達ポイントと判定し、出力を
繰り返し手段９に出力する。When the reference voltage is changed in this way, as shown in FIG. 4, the reference voltage changes from near the Max value of the two waves of the received wave to near the Max value of the three waves, so that the voltage setting unit 13a Determine the midpoint as the optimum reference voltage,
Output to the reference comparison means 7. Then, the reference comparing means 7 compares the determined reference voltage with the output of the amplifying means 6, and notifies the judging means 8 of the time when the magnitude relation is reversed, and the judging means 8 outputs the subsequent amplifying means 6 output. The first negative zero-cross point (zero-cross point a in FIG. 4) at which the sign of changes from positive to negative is determined as the arrival point of the ultrasonic wave, and the output is output to the repeating unit 9.

【００３２】以上のように、本実施例においては判定手
段８が増幅手段６の出力（受信波）の特定のポイント
（例えば３波の負のゼロクロス点）を検知可能な基準電
圧の範囲を、電圧設定手段１３が基準電圧を変化させな
がら伝搬時間より検出して、基準電圧をその範囲の中間
点に設定する。それにより安定して受信波の特定のポイ
ントを検知できるようになる。つまり、このような基準
電圧の設定動作が迅速かつ、精度良く行うことが出来、
常に最適な基準電圧に保たれた流量計測装置とすること
が出来る。As described above, in the present embodiment, the range of the reference voltage at which the determination means 8 can detect a specific point (for example, the negative zero-cross point of three waves) of the output (received wave) of the amplification means 6, The voltage setting means 13 detects the propagation time while changing the reference voltage, and sets the reference voltage at the midpoint of the range. Thereby, it becomes possible to stably detect a specific point of the received wave. In other words, such a reference voltage setting operation can be performed quickly and accurately,
The flow rate measuring device can always be kept at the optimum reference voltage.

【００３３】（実施例３） 図５は本発明の実施例３の流量計測装置のブロック図、
また、図６、図７は同流量計測装置の動作説明図であ
り、電圧設定手段１３の動作を説明したものである。図
５において１３ｃは基準比較手段７の出力と判定手段８
からの出力の時間差を計時する時間差計時部であり、１
３ａは前記時間差計時部１３ｃの出力より基準比較手段
７へ基準電圧を出力する電圧設定部であり、電圧設定部
１３ａと時間差計時部１３ｃで電圧設定手段１３を構成
している。他の構成要素は実施例１と同じであるので説
明は省略する。(Third Embodiment) FIG. 5 is a block diagram of a flow rate measuring apparatus according to a third embodiment of the present invention.
6 and 7 are operation explanatory diagrams of the flow rate measuring device, and illustrate the operation of the voltage setting means 13. In FIG. 5, 13c is the output of the reference comparing means 7 and the judging means 8.
Is a time difference timer that measures the time difference of the output from
Reference numeral 3a is a voltage setting unit for outputting a reference voltage from the output of the time difference measuring unit 13c to the reference comparing unit 7, and the voltage setting unit 13a and the time difference measuring unit 13c constitute the voltage setting unit 13. The other components are the same as those in the first embodiment, and the description thereof will be omitted.

【００３４】以上のように構成された流量計測装置につ
いて、以下その動作、作用を説明する。制御手段１２は
流量計測を開始すると送信手段５を動作させ超音波振動
子２より超音波信号を送信する。第１超音波振動子２よ
り送信された超音波信号は流路１の流れの中を伝搬し、
第２超音波振動子３で受信され、増幅手段６で制御手段
１２からの指示により、受信信号が一定の振幅になるよ
うなゲインに自動的に調整されて、基準比較手段７、判
定手段８へ出力される。基準比較手段７は増幅手段６の
出力と基準電圧とを比較し、実施例１と同様にその大小
関係が反転した時点で出力信号Ｃ１を判定手段８と時間
差計時部１３ｃに出力する。The operation and action of the flow rate measuring device configured as described above will be described below. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the ultrasonic transducer 2. The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1,
The gain is received by the second ultrasonic transducer 3, and the amplifying means 6 is automatically adjusted to a gain such that the received signal has a constant amplitude according to an instruction from the control means 12, and the reference comparing means 7 and the judging means 8 are provided. Is output to. The reference comparing means 7 compares the output of the amplifying means 6 with the reference voltage, and outputs the output signal C1 to the determining means 8 and the time difference measuring section 13c at the time when the magnitude relation is inverted as in the first embodiment.

【００３５】判定手段８では基準比較手段７の出力よ
り、図６に示すような増幅手段６の出力の符号が正から
負に変わる最初の負のゼロクロス点ａを超音波の到達ポ
イントと判定し、時間差計時部１３ｃへ出力信号Ｃ２を
出力する。時間差計時部１３ｃでは基準比較手段７の出
力信号Ｃ１と判定手段８の出力信号Ｃ２から図６に示す
ような時間差ｔｄを計時する。電圧設定部１３ａは時間
差計時部１３ｃの計時する時間差ｔｄを入力しながら基
準電力を上下に変化させていく。時間作ｔｄは基準電圧
の変化に対し図７に示すように変化する。The judging means 8 judges from the output of the reference comparing means 7 that the first negative zero-cross point a at which the sign of the output of the amplifying means 6 as shown in FIG. 6 changes from positive to negative is the arrival point of ultrasonic waves. , And outputs the output signal C2 to the time difference measuring unit 13c. The time difference measuring unit 13c measures the time difference td as shown in FIG. 6 from the output signal C1 of the reference comparing means 7 and the output signal C2 of the judging means 8. The voltage setting unit 13a changes the reference power up and down while inputting the time difference td measured by the time difference measuring unit 13c. The time td changes with changes in the reference voltage as shown in FIG.

【００３６】基準電圧が判定手段８で受信波の２波のゼ
ロクロス点を検知するレベルである受信信号の２波のピ
ーク値とほぼ同じ電圧ｖ２であるとき、時間差ｔｄはｔ
ｄｏであり受信波の１／４波長の５００ｎｓとなる。そ
して基準電圧をｖ２より大きくして判定手段８が３波の
負のゼロクロス点を検知するようにすると時間差ｔｄは
図７示すように最大値になり、以降、基準電圧の増加に
応じて小さくなり、基準電圧が３波のピーク値とほぼ同
じ電圧ｖ３の時にまた、ｔｄｏとなる。When the reference voltage is a voltage v2 that is substantially the same as the peak value of the two waves of the received signal, which is the level at which the determination means 8 detects the zero-cross point of the two waves of the received wave, the time difference td is t.
It is do, which is 500 ns, which is a quarter wavelength of the received wave. Then, when the reference voltage is made larger than v2 and the determination means 8 detects the negative zero-cross points of the three waves, the time difference td becomes the maximum value as shown in FIG. 7, and thereafter becomes smaller as the reference voltage increases. When the reference voltage is the voltage v3 which is almost the same as the peak value of the three waves, tdo becomes again.

【００３７】このように電圧設定部１３ａが基準電圧を
変化させたときの時間差ｔｄの最大値と最小値（波長の
１／４）より、時間差ｔｄがその中間点となる基準電圧
に設定する。このように動作することで、時間差計時部
１３ｃの計時する時間差が基準電圧の変化に対する変動
範囲の中間点に設定され、それにより基準電圧は受信波
の特定のゼロクロス点で安定して、検知できるに保たれ
る。このような基準電圧の設定動作が迅速かつ、精度良
く行うことが出来、常に最適な基準電圧に保たれた流量
計測装置とすることが出来る。As described above, the time difference td is set to the reference voltage which is the midpoint between the maximum value and the minimum value (1/4 of the wavelength) of the time difference td when the voltage setting unit 13a changes the reference voltage. By operating in this way, the time difference measured by the time difference measuring unit 13c is set to the midpoint of the fluctuation range with respect to the change in the reference voltage, and the reference voltage can be stably detected at a specific zero-cross point of the received wave. Kept in. Such a reference voltage setting operation can be performed quickly and accurately, and the flow rate measuring device can be always kept at the optimum reference voltage.

【００３８】（実施例４） 図８は本発明の実施例４の流量計測装置のブロック図で
あり、図９は同流量計測装置の動作説明図である。図８
において１３ｄは制御手段１２からの超音波の送信開始
信号と判定手段８からの出力より流体管路の超音波の伝
搬時間を計時すると共に基準比較手段７の出力と判定手
段８からの出力の時間差を計時する伝搬・時差計時部で
あり、１３ａは前記伝搬・時差計時部１３ｄの出力より
基準比較手段７へ基準電圧を出力する電圧設定部であ
り、電圧設定部１３ａと伝搬・時差計時部１３ｄで電圧
設定手段１３を構成している。他の構成要素は実施例１
と同じであるので説明は省略する。(Fourth Embodiment) FIG. 8 is a block diagram of a flow rate measuring device according to a fourth embodiment of the present invention, and FIG. 9 is an operation explanatory diagram of the flow rate measuring device. Figure 8
In 13 d, the ultrasonic wave transmission start signal from the control means 12 and the output from the determination means 8 are used to measure the propagation time of the ultrasonic waves in the fluid pipeline, and the time difference between the output from the reference comparison means 7 and the output from the determination means 8 is indicated. 13a is a voltage setting unit for outputting a reference voltage from the output of the propagation / time difference measuring unit 13d to the reference comparing unit 7, and the voltage setting unit 13a and the propagation / time difference measuring unit 13d. And constitutes the voltage setting means 13. The other components are the same as in the first embodiment.
The description is omitted because it is the same as.

【００３９】以上のように構成された流量計測装置につ
いて、以下その動作、作用を説明する。制御手段１２は
流量計測を開始すると送信手段５を動作させ超音波振動
子２より超音波信号を送信する。第１超音波振動子２よ
り送信された超音波信号は流路１の流れの中を伝搬し、
第２超音波振動子３で受信され、増幅手段６で制御手段
１２からの指示により、受信信号が一定の振幅になるよ
うなゲインに自動的に調整されて、基準比較手段７、判
定手段８へ出力される。基準比較手段７は増幅手段６の
出力と基準電圧とを比較し、実施例１と同様にその大小
関係が反転した時点を判定手段８へ出力すると共に伝搬
・時差計時部１３ｄに通知する。The operation and action of the flow rate measuring device configured as described above will be described below. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the ultrasonic transducer 2. The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1,
The gain is received by the second ultrasonic transducer 3, and the amplifying means 6 is automatically adjusted to a gain such that the received signal has a constant amplitude according to an instruction from the control means 12, and the reference comparing means 7 and the judging means 8 are provided. Is output to. The reference comparing means 7 compares the output of the amplifying means 6 with the reference voltage, outputs the time when the magnitude relation is reversed to the determining means 8 and notifies the propagation / time difference time measuring unit 13d as in the first embodiment.

【００４０】判定手段８では基準比較手段７の出力よ
り、図９に示すような増幅手段６の出力の符号が正から
負に変わる最初の負のゼロクロスａ点を超音波の到達ポ
イントと判定し、伝搬・時差計時部１３ｄへ出力する。
伝搬・時差計時部１３ｄでは図９に示すように基準比較
手段７の出力信号Ｃ１と判定手段８の出力信号Ｃ２から
図９に示すような時間差ｔｄと、制御手段１２からの送
信開始信号と判定手段８の出力から流体管路の超音波の
伝搬時間を計時する。The judging means 8 judges from the output of the reference comparing means 7 that the sign of the output of the amplifying means 6 as shown in FIG. , And outputs to the propagation / time difference measuring unit 13d.
The propagation / time difference measuring unit 13d determines from the output signal C1 of the reference comparison unit 7 and the output signal C2 of the determination unit 8 as shown in FIG. 9, the time difference td as shown in FIG. 9, and the transmission start signal from the control unit 12. The propagation time of the ultrasonic wave in the fluid conduit is measured from the output of the means 8.

【００４１】それから電圧設定部１３ａは図９の基準電
圧ｂに示すように伝搬・時差計時部１３ｄの計時する超
音波の伝搬時間が超音波の駆動周波数の１波長分（５０
０ＫＨｚ：２μｓ）短くなるまで基準電圧を僅かずつ下
げていく（１波長短くなった時の基準比較手段７と判定
手段８の出力を出力信号Ｂ１、Ｂ２に示す）。その後、
基準電圧を若干上げて、超音波の伝搬時間が元に戻り、
判定手段８の出力が出力信号Ｂ２からＣ２になった時点
での基準比較手段７の出力信号Ｃ１と判定手段８の出力
信号Ｃ２から時間差ｔｄを伝搬・時差計時部１３ｄで計
時する（この時の基準電圧が判定手段８で受信波の３波
の負のゼロクロス点を検知できる基準電圧設定範囲の下
限値となり、上限値は３波のピーク値電圧となる）。こ
の時の時間差ｔｄを初期値ｔｄ０として、電圧設定部１
３ａは、伝搬・時差計時部１３ｄで計時する時間差ｔｄ
が基準電圧の電圧設定範囲の上限時の時間差（ｔｄ１と
し、ｔｄ１は基準電圧が受信波の３波のピーク電圧時の
時間差であるので１波長２μｓ／４で５００ｎｓ）との
中間点である（ｔｄ０―駆動周波数波長／４）／２＋駆
動周波数波長／４となる基準電圧ｃまで電圧を上げてい
く（例えば時間差ｔｄ０＝９００ｎｓ、駆動周波数波長
２μｓとするとｔｄ＝（９００−２０００／４）／２＋
２０００／４＝７００ｎｓとなるまで電圧を上げてい
く）。Then, the voltage setting unit 13a, as shown by the reference voltage b in FIG. 9, the propagation time of the ultrasonic wave measured by the propagation / time difference measuring unit 13d is one wavelength (50 wavelengths) of the ultrasonic drive frequency.
0 KHz: 2 μs) The reference voltage is gradually decreased until it becomes shorter (the outputs of the reference comparison means 7 and the determination means 8 when the wavelength is shortened are shown in the output signals B1 and B2). afterwards,
Raise the reference voltage slightly and return the ultrasonic propagation time to the original
The time difference td is measured from the output signal C1 of the reference comparison means 7 and the output signal C2 of the judgment means 8 at the time when the output of the judgment means 8 changes from the output signal B2 to C2 by the propagation / time difference timer 13d (at this time, The reference voltage is the lower limit value of the reference voltage setting range in which the determination means 8 can detect the three negative zero-cross points of the received wave, and the upper limit value is the peak value voltage of the three waves). The time difference td at this time is set to the initial value td0, and the voltage setting unit 1
3a is a time difference td measured by the propagation / time difference measuring unit 13d.
Is an intermediate point between the time difference at the upper limit of the voltage setting range of the reference voltage (td1, where td1 is the time difference between the peak voltages of the three waves of the received waves, and one wavelength is 2 μs / 4 and 500 ns). td0-driving frequency wavelength / 4) / 2 + The voltage is increased to the reference voltage c which becomes the driving frequency wavelength / 4 (for example, when the time difference td0 = 900 ns and the driving frequency wavelength 2 μs, td = (900-2000 / 4) / 2 +
Increase the voltage until 2000/4 = 700 ns).

【００４２】このように動作することで、基準電圧ｃは
基準電圧ｂの基準比較手段出力Ｃ１の立ち下がりから受
信波の３波のピーク迄の時間の中間点に設定される。つ
まり伝搬・時差計時部１３ｄが基準比較手段７の出力信
号と判定手段８の出力信号から計時する時間差ｔｄのみ
を用いて、基準電圧を設定する。設定動作として電圧設
定可能範囲の下限である図９の基準電圧ｂだけを探索す
る動作のみで、設定すべき時間差ｔｄが求まるので基準
電圧の設定動作がさらに迅速にかつ、精度良く行うこと
が出来、常に最適な基準電圧に保たれた流量計測装置と
することが出来る。By operating in this way, the reference voltage c is set at the midpoint of the time from the fall of the reference comparing means output C1 of the reference voltage b to the peak of the three waves of the received wave. That is, the reference voltage is set by using only the time difference td measured by the output signal of the reference comparison means 7 and the output signal of the determination means 8 by the propagation / time difference timer 13d. As the setting operation, the time difference td to be set is obtained only by the operation of searching only the reference voltage b of FIG. 9 which is the lower limit of the voltage settable range, so that the setting operation of the reference voltage can be performed more quickly and accurately. Therefore, the flow rate measuring device can be always kept at the optimum reference voltage.

【００４３】（実施例５） 図１０は本発明の実施例５の流量計測装置のブロック図
であり、図１１は同流量計測装置の動作説明図である。
図１０において１３ｅは基準比較手段７の出力の信号幅
を計時するパルス幅計時部であり、１３ａは前記パルス
幅計時部１３ｅの出力より基準比較手段へ基準電圧を出
力する電圧設定部であり、電圧設定部１３ａとパルス幅
計時部１３ｅから電圧設定手段１３を構成している。他
の構成要素は実施例１と同じであるので説明は省略す
る。(Fifth Embodiment) FIG. 10 is a block diagram of a flow rate measuring device according to a fifth embodiment of the present invention, and FIG. 11 is an operation explanatory diagram of the flow rate measuring device.
In FIG. 10, 13e is a pulse width timer which measures the signal width of the output of the reference comparing means 7, 13a is a voltage setting portion which outputs a reference voltage from the output of the pulse width timer 13e to the reference comparing means, The voltage setting unit 13 is composed of the voltage setting unit 13a and the pulse width measuring unit 13e. The other components are the same as those in the first embodiment, and the description thereof will be omitted.

【００４４】以上のように構成された流量計測装置につ
いて、以下その動作、作用を説明する。制御手段１２は
流量計測を開始すると送信手段５を動作させ超音波振動
子２より超音波信号を送信する。第１超音波振動子２よ
り送信された超音波信号は流路１の流れの中を伝搬し、
第２超音波振動子３で受信され、増幅手段６で制御手段
１２からの指示により、受信信号が一定の振幅になるよ
うなゲインに自動的に調整されて、基準比較手段７、判
定手段８へ出力される。基準比較手段７は増幅手段６の
出力と基準電圧とを比較し、実施例１と同様にその大小
関係が反転した時点を判定手段８へ出力すると共にパル
ス幅計時部１３ｄに通知する。判定手段８では基準比較
手段７の出力より、図１１に示すような増幅手段６の出
力の符号が正から負に変わる最初の負のゼロクロスａ点
を超音波の到達ポイントと判定し、パルス幅計時部１３
ｅへ出力する。パルス幅計時部１３ｅでは図１１に示す
ように基準比較手段７の出力信号Ｃ１の負パルスの幅と
判定手段８の出力信号Ｃ２から図１１に示すような時間
ｔｗと、制御手段１２からの送信開始信号と判定手段８
の出力から流体管路の超音波の伝搬時間を計時する。The operation and action of the flow rate measuring device constructed as above will be described below. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the ultrasonic transducer 2. The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1,
The gain is received by the second ultrasonic transducer 3, and the amplifying means 6 is automatically adjusted to a gain such that the received signal has a constant amplitude according to an instruction from the control means 12, and the reference comparing means 7 and the judging means 8 are provided. Is output to. The reference comparing means 7 compares the output of the amplifying means 6 with the reference voltage, and outputs the time when the magnitude relationship is reversed to the determining means 8 as in the first embodiment, and also notifies the pulse width timer 13d. The determination means 8 determines from the output of the reference comparison means 7 that the first negative zero-cross point a at which the sign of the output of the amplification means 6 as shown in FIG. Timing unit 13
Output to e. In the pulse width timer 13e, as shown in FIG. 11, the width of the negative pulse of the output signal C1 of the reference comparison means 7 and the output signal C2 of the determination means 8 are used as shown in FIG. Start signal and determination means 8
The propagation time of ultrasonic waves in the fluid conduit is measured from the output of.

【００４５】それから電圧設定部１３ａは図１１の基準
電圧ｂに示すようにパルス幅計時部１３ｅで時する超音
波の伝搬時間が超音波の駆動周波数の１波長分（５００
ＫＨｚ：２μｓ）短くなるまで基準電圧を僅かずつ下げ
ていく（１波長短くなった時の基準比較手段７と判定手
段８の出力を出力信号Ｂ１、Ｂ２に示す）。その後、基
準電圧を若干上げて、判定手段８の出力が出力信号Ｂ２
からＣ２になった時点での基準比較手段７の出力信号Ｃ
１の負パルス幅ｔｗをパルス幅計時部１３ｅで計時す
る。そしてこの時の時間ｔｗを初期値ｔｗ０として、電
圧設定部１３ａは、パルス幅計時部１３ｅで計時する時
間ｔｗがｔｗ０／２となる基準電圧ｃまで電圧を上げて
いく。Then, the voltage setting section 13a, as shown by the reference voltage b in FIG. 11, the propagation time of the ultrasonic wave which is measured by the pulse width measuring section 13e is one wavelength (500 wavelengths) of the driving frequency of the ultrasonic wave.
KHz: 2 μs) The reference voltage is gradually decreased until it becomes shorter (the outputs of the reference comparison means 7 and the determination means 8 when the wavelength is shortened are shown in the output signals B1 and B2). After that, the reference voltage is slightly increased, and the output of the determination means 8 is the output signal B2.
The output signal C of the reference comparison means 7 at the time when it becomes C2 from C
The negative pulse width tw of 1 is counted by the pulse width timer 13e. Then, with the time tw at this time as the initial value tw0, the voltage setting unit 13a increases the voltage to the reference voltage c at which the time tw measured by the pulse width timer 13e is tw0 / 2.

【００４６】このように動作することで、基準電圧ｃは
基準電圧ｂと受信波の３波のピーク電圧のほぼ中間点に
設定される。つまりパルス幅計時部１３ｅが計時する負
パルス幅ｔｗのみを用いて、基準電圧を設定する。設定
動作として図１１の基準電圧ｂだけを探索する動作のみ
で、設定すべきパルス幅ｔｗが求まるので基準電圧の設
定動作がさらに迅速で、精度良く行うことが出来、常に
最適な基準電圧に保たれた流量計測装置とすることが出
来る。By operating in this way, the reference voltage c is set at an approximately midpoint between the reference voltage b and the peak voltages of the three received waves. That is, the reference voltage is set by using only the negative pulse width tw measured by the pulse width timer 13e. Since the pulse width tw to be set is obtained only by the operation of searching only the reference voltage b of FIG. 11 as the setting operation, the setting operation of the reference voltage can be performed more quickly and accurately, and the optimum reference voltage is always maintained. It can be a dripping flow rate measuring device.

【００４７】（実施例６） 図１２は本発明の実施例６の流量計測装置のブロック図
である。図１２において１３ｄは基準比較手段７の出力
と判定手段８からの出力の時間差を計時する伝搬・時差
計時部であり、１３ｆは電圧設定部１３ａの設定値を記
憶する記憶部であり、１３ａは制御手段１２の指示によ
り伝搬・時差計時部１３ｄの出力、もしくは記憶部１３
ｆの出力のどちらかに応じた基準電圧を基準比較手段７
へ出力する電圧設定部であり、電圧設定部１３ａと伝搬
・時差計時部１３ｄと記憶部１３ｆで電圧設定手段１３
を構成している。他の構成要素は実施例１と同じである
ので説明は省略する。以上のように構成された流量計測
装置について、以下その動作、作用を説明する。(Sixth Embodiment) FIG. 12 is a block diagram of a flow rate measuring apparatus according to a sixth embodiment of the present invention. In FIG. 12, 13d is a propagation / time difference timer that measures the time difference between the output of the reference comparison means 7 and the output from the determination means 8, 13f is a storage portion that stores the set value of the voltage setting portion 13a, and 13a is According to the instruction of the control means 12, the output of the propagation / time difference timer 13d or the storage 13
The reference voltage corresponding to either of the outputs of f is the reference comparison means 7
The voltage setting unit 13a includes a voltage setting unit 13a, a propagation / time difference timer unit 13d, and a storage unit 13f.
Are configured. The other components are the same as those in the first embodiment, and the description thereof will be omitted. The operation and action of the flow rate measuring device configured as described above will be described below.

【００４８】制御手段１２は流量計測を開始すると送信
手段５を動作させ超音波振動子２より超音波信号を送信
する。第１超音波振動子２より送信された超音波信号は
流路１の流れの中を伝搬し、第２超音波振動子３で受信
され、増幅手段６で制御手段１２からの指示により、受
信信号が一定の振幅になるようなゲインに自動的に調整
されて、基準比較手段７、判定手段８へ出力される。基
準比較手段７は増幅手段６の出力と基準電圧とを比較
し、実施例１と同様にその大小関係が反転した時点を判
定手段８へ出力すると共に伝搬・時差計時部１３ｄに通
知する。When the flow rate measurement is started, the control means 12 operates the transmission means 5 to transmit the ultrasonic signal from the ultrasonic transducer 2. The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the flow path 1, is received by the second ultrasonic transducer 3, and is received by the amplifying means 6 according to an instruction from the control means 12. The signal is automatically adjusted to a gain so that the signal has a constant amplitude, and output to the reference comparison unit 7 and the determination unit 8. The reference comparing means 7 compares the output of the amplifying means 6 with the reference voltage, outputs the time when the magnitude relation is reversed to the determining means 8 and notifies the propagation / time difference time measuring unit 13d as in the first embodiment.

【００４９】判定手段８では基準比較手段７の出力よ
り、図９に示すような増幅手段６の出力の符号が正から
負に変わる最初の負のゼロクロスａ点を超音波の到達ポ
イントと判定し、伝搬・時差計時部１３ｄへ出力する。
伝搬・時差計時部１３ｄでは図９に示すように基準比較
手段７の出力信号Ｃ１と判定手段８の出力信号Ｃ２から
図９に示すような時間差ｔｄと、制御手段１２からの送
信開始信号と判定手段８の出力から流体管路の超音波の
伝搬時間を計時する。The judging means 8 judges from the output of the reference comparing means 7 that the first negative zero-cross point a at which the sign of the output of the amplifying means 6 as shown in FIG. , And outputs to the propagation / time difference measuring unit 13d.
The propagation / time difference measuring unit 13d determines from the output signal C1 of the reference comparison unit 7 and the output signal C2 of the determination unit 8 as shown in FIG. 9, the time difference td as shown in FIG. 9, and the transmission start signal from the control unit 12. The propagation time of the ultrasonic wave in the fluid conduit is measured from the output of the means 8.

【００５０】それから電圧設定部１３ａは記憶部１３ｆ
が初期化直後でデータが何も記憶されていない状態、ま
たは定期的（例えば１ヶ月に一度）な更新時期である場
合に、制御手段１２から出される記憶部１３ｆの更新指
示により伝搬・時差計時部１３ｄの計時する時間差をも
とに実施例４のような基準電圧設定動作を行い、その設
定値を記憶部１３ｆに記憶する。そして、制御手段１２
から記憶部１３ｆの更新指示が出されていない場合に
は、電圧設定部１３ａは記憶部１３ｆに記憶される設定
値で基準電圧を設定し基準比較手段７に出力する。Then, the voltage setting unit 13a stores the storage unit 13f.
In the state where no data is stored immediately after initialization or when it is a regular (for example, once a month) update time, the propagation / time difference time measurement is performed by the update instruction of the storage unit 13f issued from the control means 12. Based on the time difference measured by the unit 13d, the reference voltage setting operation as in the fourth embodiment is performed, and the set value is stored in the storage unit 13f. And the control means 12
When the instruction to update the storage unit 13f is not issued from the storage unit 13f, the voltage setting unit 13a sets the reference voltage with the set value stored in the storage unit 13f and outputs the reference voltage to the reference comparison unit 7.

【００５１】このように動作することで、一旦、電圧設
定部１３ａで基準電圧を設定した後の設定動作は記憶部
１３ｆに記憶されている設定値で基準電圧が設定される
ので基準電圧設定動作が迅速に行われる。さらにこれは
記憶部１３ｆを不揮発性の記憶部とすることにより、低
消費電力の目的で行われる流量計測時以外の期間に電源
を遮断し、計測開始時に電源が再投入される流量計測装
置にはとくに効果を有する。以上のように基準電圧の設
定動作が迅速かつ、精度良く行うことが出来、常に最適
な基準電圧に保たれた流量計測装置とすることが出来
る。By operating in this way, the reference voltage is set by the set value stored in the storage section 13f in the setting operation after the reference voltage is once set by the voltage setting section 13a. Is done quickly. Furthermore, by making the storage unit 13f a non-volatile storage unit, the power supply is shut off during periods other than the flow rate measurement performed for the purpose of low power consumption, and the power supply is turned on again at the start of the measurement. Has a particular effect. As described above, the setting operation of the reference voltage can be performed quickly and accurately, and the flow rate measuring device can be always kept at the optimum reference voltage.

【００５２】（実施例７） 図１３は本発明の実施例７の流量計測装置の動作説明図
であり、本実施例では電圧設定部１３ａは増幅手段６の
ゲインが変更された場合に基準比較手段７への基準電圧
の更新を行うようにしたものである。(Embodiment 7) FIG. 13 is an operation explanatory view of a flow rate measuring apparatus according to Embodiment 7 of the present invention. In this embodiment, the voltage setting unit 13a performs reference comparison when the gain of the amplifying means 6 is changed. The reference voltage to the means 7 is updated.

【００５３】電圧設定部１３ａの動作を図１３のフロー
チャートを用いて説明する。制御手段１２が流量計測を
開始すると、まず最初に基準電圧設定の為の予備の流量
計測を行う（Ｓｔｅｐ１）。（この予備の流量計測は通
常の流量計測に比べ繰り返し手段９で繰り返される回数
が少なく短時間で終了するものである）そして予備流量
計測の結果、増幅手段６のゲインが変更されたかどうか
判定する。（Ｓｔｅｐ２）ゲインが変更されていた場
合、電圧設定部１３ａにより基準電圧設定動作が行われ
て（Ｓｔｅｐ３）、流量計測が行われる（Ｓｔｅｐ
９）。The operation of the voltage setting section 13a will be described with reference to the flowchart of FIG. When the control means 12 starts the flow rate measurement, first, the preliminary flow rate measurement for setting the reference voltage is performed (Step 1). (This preliminary flow rate measurement has a smaller number of repetitions by the repeating means 9 than the normal flow rate measurement and ends in a short time.) Then, as a result of the preliminary flow rate measurement, it is determined whether the gain of the amplifying means 6 has been changed. . (Step 2) When the gain has been changed, the voltage setting unit 13a performs the reference voltage setting operation (Step 3), and the flow rate is measured (Step 3).
9).

【００５４】また、ゲインが変更が無ければ設定動作な
しに通常の流量計測が行われる（Ｓｔｅｐ９）。これは
図２０の従来例の説明図で示すように増幅手段６のゲイ
ンを変更した場合、基準電圧と受信信号の相対関係が変
化するので基準電圧を再設定する方が望ましいからであ
る。以上のように動作することで、増幅手段６のゲイン
が変更され、基準電圧の再設定が必要になった際に、基
準電圧の設定動作が迅速かつ、精度良く行うことが出
来、常に最適な基準電圧に保たれた流量計測装置とする
ことが出来る。If the gain is not changed, normal flow rate measurement is performed without setting operation (Step 9). This is because when the gain of the amplifying means 6 is changed as shown in the explanatory view of the conventional example of FIG. 20, it is preferable to reset the reference voltage because the relative relationship between the reference voltage and the received signal changes. By operating as described above, when the gain of the amplifying means 6 is changed and the reference voltage needs to be reset, the setting operation of the reference voltage can be performed quickly and accurately, and it is always optimum. The flow rate measuring device can be kept at the reference voltage.

【００５５】（実施例８） 図１４は本発明の実施例８の流量計測装置の動作説明
図、図１５流量と受信信号の感度（振幅レベル）の関係
を示す図である。図１５において、上流の超音波振動子
から下流側へ送信した場合の流量と受信信号の振幅レベ
ルを実線で示し、下流の超音波振動子から上流側へ送信
した場合の流量と受信信号の感度（振幅レベル）を点線
で示している。図１５に示すように感度の低下具合は異
なるものの、どちらも流量の増加と共に受信信号の感度
は低下している。従って増幅手段６では流量の増加によ
る感度低下に対し一定の振幅レベルとなるようにゲイン
を上げて調整する。そして電圧設定部１３ａは流量算出
手段１１で算出した流量の変化があった場合に基準比較
手段７への基準電圧の更新を行うようにしたものであ
る。電圧設定部１３ａの動作を図１３のフローチャート
を用いて説明する。(Embodiment 8) FIG. 14 is an operation explanatory view of a flow rate measuring apparatus according to Embodiment 8 of the present invention, and FIG. 15 is a diagram showing a relationship between flow rate and sensitivity (amplitude level) of a received signal. In FIG. 15, the solid line indicates the flow rate and the amplitude level of the received signal when transmitting from the upstream ultrasonic transducer to the downstream side, and the flow rate and the sensitivity of the received signal when transmitting from the downstream ultrasonic transducer to the upstream side. (Amplitude level) is shown by a dotted line. As shown in FIG. 15, although the degree of decrease in sensitivity is different, the sensitivity of the received signal decreases in both cases as the flow rate increases. Therefore, in the amplifying means 6, the gain is increased and adjusted so that the amplitude level becomes constant with respect to the sensitivity decrease due to the increase of the flow rate. The voltage setting unit 13a updates the reference voltage to the reference comparison unit 7 when the flow rate calculated by the flow rate calculation unit 11 changes. The operation of the voltage setting unit 13a will be described with reference to the flowchart of FIG.

【００５６】制御手段１２で流量計測を開始すると、ま
ず最初に基準電圧設定の為の予備の流量計測を行う（Ｓ
ｔｅｐ１）（この予備の流量計測は通常の流量計測に比
べ繰り返し手段９で繰り返される回数が少なく短時間で
終了するものである）。When the flow rate measurement is started by the control means 12, first, the preliminary flow rate measurement for setting the reference voltage is performed (S
(Step 1) (This preliminary flow rate measurement has a smaller number of repetitions by the repeating means 9 than the normal flow rate measurement, and is completed in a short time).

【００５７】そして予備流量計測の結果、流量が５００
０Ｌ／Ｈ以上かどうか判定する（Ｓｔｅｐ３）。５００
０Ｌ／Ｈ未満であれば更に１００００Ｌ／Ｈ以上か判定
する（Ｓｔｅｐ５）。その結果、流量域に応じてフラグ
がセットされ（Ｓｔｅｐ２、４、６）、前回の流量計測
時と比べ流量域が変化しているかが判定され、（Ｓｔｅ
ｐ７）流量域が変化していれば電圧設定部１３ａにより
基準電圧設定動作が行われ（Ｓｔｅｐ８）、その後、通
常の流量計測が行われる。また、流量域に変化がなけれ
ば設定動作なしに通常の流量計測が行われる（Ｓｔｅｐ
９）。As a result of the preliminary flow rate measurement, the flow rate is 500
It is determined whether it is 0 L / H or more (Step 3). 500
If it is less than 0 L / H, it is further determined whether it is 10,000 L / H or more (Step 5). As a result, a flag is set according to the flow rate range (Steps 2, 4, and 6), and it is determined whether the flow rate range has changed compared to the previous flow rate measurement, and (Step
p7) If the flow rate range has changed, the voltage setting unit 13a performs the reference voltage setting operation (Step 8), and then the normal flow rate measurement is performed. Also, if there is no change in the flow rate range, normal flow rate measurement is performed without setting operation (Step).
9).

【００５８】以上のように動作することで、流量が変化
し増幅手段６のゲインが変更され、基準電圧の再設定が
必要になった際に、基準電圧の設定動作が迅速かつ、精
度良く行われ、常に最適な基準電圧に保たれた流量計測
装置とすることが出来る。By the above operation, when the flow rate is changed and the gain of the amplifying means 6 is changed and the reference voltage needs to be reset, the setting operation of the reference voltage is performed quickly and accurately. Therefore, the flow rate measuring device can be always kept at the optimum reference voltage.

【００５９】（実施例９） 図１６は本発明の実施例９の流量計測装置のブロック
図、図１７は本発明の実施例９の流量計測装置の動作説
明図である。図１６において、１３ｇは計時手段１０の
出力より流体の温度を算出する温度算出部であり、１３
ｄは制御手段１２からの超音波の送信開始信号と判定手
段８からの出力より流体管路の超音波の伝搬時間を計時
すると共に基準比較手段７の出力と判定手段８からの出
力の時間差を計時する伝搬・時差計時部であり、１３ａ
は前記温度算出部１３ｇからの出力と伝搬・時差計時部
１３ｄの出力より基準比較手段７へ基準電圧を出力する
電圧設定部であり、電圧設定部１３ａと伝搬・時差計時
部１３ｄ、温度算出部１３ｇで電圧設定手段１３を構成
している。他の構成要素は実施例１と同じであるので説
明は省略する。(Embodiment 9) FIG. 16 is a block diagram of a flow rate measuring device according to a ninth embodiment of the present invention, and FIG. 17 is an operation explanatory diagram of a flow rate measuring device according to a ninth embodiment of the present invention. In FIG. 16, 13 g is a temperature calculation unit that calculates the temperature of the fluid from the output of the time measuring means 10.
Reference numeral d denotes the ultrasonic wave transmission start signal from the control means 12 and the output from the determination means 8 to measure the propagation time of the ultrasonic waves in the fluid line, and the time difference between the output from the reference comparison means 7 and the output from the determination means 8. Propagation / time difference timekeeping part that keeps time, 13a
Is a voltage setting unit that outputs a reference voltage to the reference comparison unit 7 from the output from the temperature calculating unit 13g and the output from the propagation / time difference measuring unit 13d. The voltage setting unit 13a, the propagation / time difference measuring unit 13d, and the temperature calculating unit The voltage setting means 13 is composed of 13 g. The other components are the same as those in the first embodiment, and the description thereof will be omitted.

【００６０】以上のように構成された流量計測装置につ
いて、以下その動作、作用を説明する。温度算出部１３
ｇは計時手段１１の計時する上流から下流へのｎ回分の
測定時間をｔ１、下流から上流へのｎ回分の測定時間を
ｔ２から（式２）により流体の温度を算出する（超音波
振動子間の流れ方向の有効距離をＬ（単位ｍ）、被測定
流体の流速をＶ（単位ｍ／ｓ）、センサ角度をφ、音速
をＣ＝３３１＋０．６×Ｔｍｐ、Ｔ１＝Ｌ／（Ｃ＋Ｖｃ
ｏｓφ）、Ｔ２＝Ｌ／（Ｃ−Ｖｃｏｓφ）とする）。The operation and action of the flow rate measuring device configured as described above will be described below. Temperature calculator 13
g is the measurement time of the n times from the upstream to the downstream measured by the time measuring means 11 from t1, and the measurement time of the n times from the downstream to the upstream is calculated from t2 (Equation 2) to calculate the temperature of the fluid (ultrasonic transducer). The effective distance in the flow direction is L (unit: m), the flow velocity of the fluid to be measured is V (unit: m / s), the sensor angle is φ, the sound velocity is C = 331 + 0.6 × Tmp, T1 = L / (C + Vc).
osφ), and T2 = L / (C−Vcosφ)).

【００６１】 Ｔｍｐ＝（Ｌ／２（１／Ｔ１＋１／Ｔ２）−３３１）／０．６・・・（式２） 温度算出部１３ｇの出力を受けて基準電圧を設定する電
圧設定部１３ａの動作を図１７のフローチャートを用い
て説明する。制御手段１２で流量計測を開始すると、ま
ず最初に基準電圧設定の為の予備の流量計測を行う。
（Ｓｔｅｐ１）（この予備の流量計測は通常の流量計測
に比べ繰り返し手段９で繰り返される回数が少なく短時
間で終了するものである）そして予備流量計測の結果、
計時手段１０の計時した時間より（式２）に基づいて流
体の温度を算出する。そして、流体の温度が前回に比べ
１０℃以上変化しているか判定する（Ｓｔｅｐ２）。Tmp = (L / 2 (1 / T1 + 1 / T2) -331) /0.6 (Equation 2) Operation of the voltage setting unit 13a that receives the output of the temperature calculation unit 13g and sets the reference voltage Will be described with reference to the flowchart of FIG. When the flow rate measurement is started by the control means 12, first, the preliminary flow rate measurement for setting the reference voltage is performed.
(Step 1) (This preliminary flow rate measurement has a smaller number of repetitions by the repeater 9 than the normal flow rate measurement, and is completed in a short time) and the result of the preliminary flow rate measurement,
The temperature of the fluid is calculated based on (Equation 2) from the time measured by the time measuring means 10. Then, it is determined whether or not the temperature of the fluid has changed by 10 ° C. or more compared to the previous time (Step 2).

【００６２】その結果、１０℃以上変化していれば電圧
設定部１３ａにより基準電圧設定動作が行われ（Ｓｔｅ
ｐ３）、その後、通常の流量計測が行われる（Ｓｔｅｐ
４）。また、１０℃以上変化していなければ設定動作な
しに通常の流量計測が行われる（Ｓｔｅｐ４）。As a result, if there is a change of 10 ° C. or more, the voltage setting unit 13a performs the reference voltage setting operation (Step
p3), and then the normal flow rate measurement is performed (Step)
4). If the temperature does not change by 10 ° C. or more, normal flow rate measurement is performed without setting operation (Step 4).

【００６３】尚、説明では１０℃以上の温度変化で基準
電圧設定動作を行うとしたが、温度変化による増幅手段
６のゲインが変更される最低温度幅に定めればよい。以
上のように動作することで、流体の温度が一定以上変化
するごとに基準電圧の設定動作が迅速かつ、精度良く行
われ、常に最適な基準電圧に保たれた流量計測装置とす
ることが出来る。In the description, the reference voltage setting operation is performed with a temperature change of 10 ° C. or more, but it may be set to the minimum temperature range in which the gain of the amplifying means 6 is changed due to the temperature change. By operating as described above, the reference voltage setting operation can be performed quickly and accurately whenever the temperature of the fluid changes by a certain amount or more, and the flow rate measuring device can be always kept at the optimum reference voltage. .

【００６４】 以上説明したように本発明の実施例の効
果を総括的に述べれば次の通りである。[0064] virtue of embodiments of the present invention as described on the following
The overall result is as follows .

【００６５】 判定手段が増幅手段の出力の特定のポイ
ント（例えば３波の負のゼロクロス点）を検知可能な基
準電圧の範囲を、電圧設定手段が基準電圧を変化させな
がら伝搬時間より検出して、基準電圧をその範囲に設定
することで安定して受信波を検知できるようになり、こ
のような基準電圧の設定動作が迅速かつ、精度良く行わ
れ、常に最適な基準電圧に保たれた流量計測装置とする
ことが出来る効果がある。 [0065]-size range of detectable reference voltage specific points of the output of the constant means amplifying means (e.g. three-wave negative zero-crossing point of), was detected from the propagation time while the voltage setting means to change the reference voltage By setting the reference voltage within that range, it becomes possible to detect the received wave in a stable manner.This kind of reference voltage setting operation is performed quickly and accurately, and the optimum reference voltage is always maintained. There is an effect that it can be used as a flow rate measuring device.

【００６６】また、電圧設定部が基準比較手段の出力と
判定手段の出力から計時する時間差を、超音波の駆動周
波長（２μｓ）を基に予め設定された値になるように規
準電圧を設定することで、安定して受信波を検知できる
ようになり、このような基準電圧の設定動作が迅速か
つ、精度良く行われ、常に最適な基準電圧に保たれた流
量計測装置とすることが出来る効果がある。[0066] Further, conductive time difference for measuring the output of the output determination means pressure setting unit reference comparison means, a reference voltage such that the predetermined value based on the ultrasound drive frequency length (2 [mu] s) By setting it, it becomes possible to stably detect the received wave, and such a reference voltage setting operation can be performed quickly and accurately, and a flow rate measurement device that is always kept at the optimum reference voltage can be obtained. There is an effect that can be done.

【００６７】また、基準電圧が電圧設定手段により増幅
手段の出力のピーク電圧に対し所定の比率の電圧に自動
的に設定され、基準電圧の設定動作が迅速かつ、精度良
く行われ、常に最適な基準電圧に保たれた流量計測装置
とすることが出来る効果がある。[0067] The base reference voltage is automatically set to the voltage of a predetermined ratio with respect to the peak voltage of the output of the amplification means by the voltage setting means, the setting operation of the reference voltage and quickly carried out accurately, always optimally There is an effect that it can be used as a flow rate measuring device that is maintained at various reference voltages.

【００６８】また、時間差より電圧設定部が基準電圧の
設定可能範囲を認識し、設定可能範囲の中間点で電圧設
定部が基準電圧を設定するので、受信信号に対して特定
のポイントに基準電圧を設定することが出来、基準電圧
の設定が迅速かつ、精度良く行われ、常に最適な基準電
圧に保たれた流量計測装置とすることが出来る効果があ
る。[0068] The voltage setting unit than the time between the difference recognizes the setting range of the reference voltage, the voltage setting unit at the midpoint settable range to set the reference voltage, a specific point on the received signal The reference voltage can be set, the reference voltage can be set quickly and accurately, and there is an effect that the flow rate measuring device can be always kept at the optimum reference voltage.

【００６９】また、受信信号に対して特定のポイントに
基準電圧を設定することが出来、基準電圧の設定動作が
迅速かつ、精度良く行われ、常に最適な基準電圧に保た
れた流量計測装置とすることが出来る効果がある。[0069] Further, it is possible to set the reference voltage to a certain point with respect to received signals, setting operation of the reference voltage and quickly carried out accurately, the flow rate measuring apparatus was always kept at an optimum reference voltage There is an effect that can be.

【００７０】また、一旦、電圧設定部で基準電圧を設定
した後の設定動作は記憶部に記憶されている設定値で基
準電圧が設定されるので基準電圧設定動作が迅速に行わ
れ、かつ精度良く行うことが出来、常に最適な基準電圧
に保たれた流量計測装置とすることが出来る効果があ
る。[0070] Another aspect Dan, setting operation after setting the reference voltage by the voltage setting unit reference voltage setting operation because the reference voltage is set is made quickly by setting values stored in the storage unit, and There is an effect that the flow rate measuring device can be performed with high accuracy and always kept at the optimum reference voltage.

【００７１】また、増幅手段のゲインが変更され、基準
電圧の再設定が必要になった際に、電圧設定部により基
準電圧の設定動作が迅速かつ、精度良く行われ、常に最
適な基準電圧に保たれた流量計測装置とすることが出来
る効果がある。[0071] Furthermore, changes the gain of amplifier means, when the re-setting of the reference voltage is needed, the setting operation of the reference voltage and quickly by the voltage setting unit, is accurately performed, always optimum reference voltage There is an effect that the flow rate measuring device can be maintained at

【００７２】また、流量が変化し増幅手段のゲインが変
更され、基準電圧の再設定が必要になった際に、電圧設
定部により基準電圧の設定動作が迅速かつ、精度良く行
われ、常に最適な基準電圧に保たれた流量計測装置とす
ることが出来る効果がある。[0072] Furthermore, flow rate is changed the gain of the changed amplification means, when the re-setting of the reference voltage is needed, the setting operation of the reference voltage and quickly by the voltage setting unit, is accurately performed, always There is an effect that the flow rate measuring device can be maintained at the optimum reference voltage.

【００７３】また、流体の温度が一定以上変化するごと
に電圧設定部により基準電圧の設定動作が迅速かつ、精
度良く行われ、常に最適な基準電圧に保たれた流量計測
装置とすることが出来る効果がある。[0073] The setting operation of the reference voltage and quickly by the voltage setting unit every time the temperature of the flow body varies above a predetermined done accurately, be a flow rate measuring apparatus was always kept at an optimum reference voltage There is an effect that can be done.

【００７４】また、請求項１０に係る流量計測方法は、
増幅手段により所定の振幅まで増幅された受信側の振動
子の受信信号に対し、予め設定された比率の基準電圧を
電圧設定手段で出力するので、受信信号に対してほぼ一
定の比率の基準電圧とすることが出来、基準電圧の設定
が迅速かつ、精度良く行われ、常に最適な基準電圧に保
つことが出来る効果がある。The flow rate measuring method according to claim 10 is
The reference voltage having a preset ratio is output by the voltage setting device to the reception signal of the transducer on the reception side that has been amplified to a predetermined amplitude by the amplification device, so that the reference voltage has a substantially constant ratio to the reception signal. Therefore, the reference voltage can be set quickly and accurately, and the optimum reference voltage can always be maintained.

【００７５】[0075]

【発明の効果】以上のように本発明によれば、基準電圧
の設定動作が迅速かつ、精度良く行われ、常に最適な基
準電圧に保たれた流量計測装置とすることが出来る効果
がある。 As described above, according to the present invention, the reference voltage
The setting operation of the
Effect of being able to be a flow rate measuring device kept at a quasi voltage
There is.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の実施例１における流量計測装置のブロ
ック図FIG. 1 is a block diagram of a flow rate measuring device according to a first embodiment of the present invention.

【図２】同装置の動作を説明する信号波形図FIG. 2 is a signal waveform diagram explaining the operation of the device.

【図３】本発明の実施例２における流量計測装置のブロ
ック図FIG. 3 is a block diagram of a flow rate measuring device according to a second embodiment of the present invention.

【図４】同装置の動作を説明する信号波形図FIG. 4 is a signal waveform diagram explaining the operation of the device.

【図５】本発明の実施例３における流量計測装置のブロ
ック図FIG. 5 is a block diagram of a flow rate measuring device according to a third embodiment of the present invention.

【図６】同装置の動作を説明する信号波形図FIG. 6 is a signal waveform diagram explaining the operation of the device.

【図７】同装置の動作を説明する特性図FIG. 7 is a characteristic diagram illustrating the operation of the device.

【図８】本発明の実施例４における流量計測装置のブロ
ック図FIG. 8 is a block diagram of a flow rate measuring device according to a fourth embodiment of the present invention.

【図９】同装置の動作を説明する信号波形図FIG. 9 is a signal waveform diagram explaining the operation of the device.

【図１０】本発明の実施例５における流量計測装置のブ
ロック図FIG. 10 is a block diagram of a flow rate measuring device according to a fifth embodiment of the present invention.

【図１１】同装置の動作を説明する信号波形図FIG. 11 is a signal waveform diagram explaining the operation of the device.

【図１２】本発明の実施例６における流量計測装置のブ
ロック図FIG. 12 is a block diagram of a flow rate measuring device according to a sixth embodiment of the present invention.

【図１３】本発明の実施例７における流量計測装置の動
作を説明するフローチャートFIG. 13 is a flowchart illustrating an operation of the flow rate measuring device according to the seventh embodiment of the present invention.

【図１４】本発明の実施例８における流量計測装置の動
作を説明するフローチャートFIG. 14 is a flowchart illustrating an operation of the flow rate measuring device according to the eighth embodiment of the present invention.

【図１５】同装置の流量と受信信号の感度の関係を示す
特性図FIG. 15 is a characteristic diagram showing the relationship between the flow rate of the device and the sensitivity of the received signal.

【図１６】本発明の実施例９における流量計測装置のブ
ロック図FIG. 16 is a block diagram of a flow rate measuring device according to a ninth embodiment of the present invention.

【図１７】同装置の動作を説明するフローチャートFIG. 17 is a flowchart explaining the operation of the apparatus.

【図１８】従来の流量計測装置のブロック図FIG. 18 is a block diagram of a conventional flow rate measuring device.

【図１９】同装置の動作を説明する信号波形図FIG. 19 is a signal waveform diagram explaining the operation of the device.

【図２０】同装置の増幅手段の動作を説明する信号波形
図FIG. 20 is a signal waveform diagram for explaining the operation of the amplification means of the device.

【符号の説明】[Explanation of symbols]

１ 流路 ２ 第１超音波振動子 ３ 第２超音波振動子 ４ 切換手段 ５ 送信手段 ６ 増幅手段 ７ 基準比較手段 ８ 判定手段 ９ 繰り返し手段 １０ 計時手段 １１ 流量算出手段 １２ 制御手段 １３ 電圧設定手段 1 flow path 2 First ultrasonic transducer 3 Second ultrasonic transducer 4 switching means 5 Transmission means 6 amplification means 7 Standard comparison means 8 Judgment means 9 Repeating means 10 Timekeeping means 11 Flow rate calculating means 12 Control means 13 Voltage setting means

───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭54−51724（ＪＰ，Ａ) 特開 昭54−41783（ＪＰ，Ａ) 特開2002−340641（ＪＰ，Ａ) 特開2002−365110（ＪＰ，Ａ) 特開2002−333356（ＪＰ，Ａ) 特開2001−255187（ＪＰ，Ａ) 特開 平11−51724（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01F 1/66 102 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP 54-51724 (JP, A) JP 54-41783 (JP, A) JP 2002-340641 (JP, A) JP 2002-365110 ( JP, A) JP 2002-333356 (JP, A) JP 2001-255187 (JP, A) JP 11-51724 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) ) G01F 1/66 102

Claims (10)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 流体管路に設けられ超音波信号を送受信
する第１振動子及び第２振動子と、前記振動子を駆動す
る送信手段と、前記振動子の送受信を切り換える切換手
段と、前記振動子間の相互の超音波伝達を複数回行う繰
り返し手段と、超音波伝搬の累積時間に基づいて流量を
算出する流量算出手段と、受信側の振動子の受信信号を
増幅する増幅手段と、基準電圧を出力する電圧設定手段
と、前記増幅手段で増幅された信号と基準電圧とを比較
する基準比較手段と、前記基準比較手段の出力と前記増
幅手段出力とから超音波の到達ポイントを判定する判定
手段とを備え、前記電圧設定手段は、超音波の伝搬時間
に基づいて基準電圧を設定する流量計測装置。1. A first oscillator and a second oscillator provided in a fluid conduit for transmitting and receiving ultrasonic signals, transmitting means for driving the oscillator, switching means for switching transmission and reception of the oscillator, and Repeating means for performing mutual ultrasonic wave transmission between the vibrators a plurality of times, flow rate calculating means for calculating a flow rate based on the cumulative time of ultrasonic wave propagation, and amplifying means for amplifying a reception signal of the vibrator on the receiving side, A voltage setting means for outputting a reference voltage, a reference comparing means for comparing the signal amplified by the amplifying means with a reference voltage, and an ultrasonic wave arrival point is determined from the output of the reference comparing means and the amplifying means output. Flow rate measuring device for setting the reference voltage based on the propagation time of the ultrasonic wave. 【請求項２】 流体管路に設けられ超音波信号を送受信
する第１振動子及び第２振動子と、前記振動子を駆動す
る送信手段と、前記振動子の送受信を切り換える切換手
段と、前記振動子間の相互の超音波伝達を複数回行う繰
り返し手段と、超音波伝搬の累積時間に基づいて流量を
算出する流量算出手段と、受信側の振動子の受信信号を
増幅する増幅手段と、基準電圧を出力する電圧設定手段
と、前記増幅手段で増幅された信号と基準電圧とを比較
する基準比較手段と、前記基準比較手段の出力と前記増
幅手段出力とから超音波の到達ポイントを判定する判定
手段とを備え、前記電圧設定手段は、前記基準比較手段
の出力と前記判定手段からの出力の時間差に基づいて基
準電圧を設定する流量計測装置。2. A first vibrator and a second vibrator provided in a fluid conduit for transmitting and receiving ultrasonic signals, transmitting means for driving the vibrator, and switching means for switching transmission and reception of the vibrator, Repeating means for performing mutual ultrasonic wave transmission between the vibrators a plurality of times, flow rate calculating means for calculating a flow rate based on the cumulative time of ultrasonic wave propagation, and amplifying means for amplifying a reception signal of the vibrator on the receiving side, A voltage setting means for outputting a reference voltage, a reference comparing means for comparing the signal amplified by the amplifying means with a reference voltage, and an ultrasonic wave arrival point is determined from the output of the reference comparing means and the amplifying means output. Flow rate measuring device for setting the reference voltage based on the time difference between the output of the reference comparing means and the output from the determining means. 【請求項３】 電圧設定手段は、増幅手段の出力のピー
ク電圧に対し所定の比率の基準電圧を出力する請求項１
または２記載の流量計測装置。3. The voltage setting means outputs a reference voltage having a predetermined ratio to the peak voltage of the output of the amplifying means.
Or the flow rate measuring device according to 2. 【請求項４】 電圧設定手段は、基準電圧の電圧設定範
囲の上限，下限基準電圧における時間差の中間点となる
時間差である基準電圧を設定する請求項２記載の流量計
測装置。4. The flow rate measuring device according to claim 2, wherein the voltage setting means sets a reference voltage that is a time difference that is an intermediate point of time differences between the upper limit and lower limit reference voltages of the voltage setting range of the reference voltage. 【請求項５】 電圧設定手段は、基準比較手段の出力信
号のパルス幅に基づいて基準電圧の設定動作を行う請求
項１または２記載の流量計測装置。5. The flow rate measuring device according to claim 1, wherein the voltage setting means performs the setting operation of the reference voltage based on the pulse width of the output signal of the reference comparison means. 【請求項６】 電圧設定手段は、記憶部が初期化直後ま
たは定期的な更新時期である場合に、基準電圧の設定動
作を行う請求項１または２記載の流量計測装置。6. The flow rate measuring device according to claim 1, wherein the voltage setting means performs the reference voltage setting operation immediately after the storage unit is initialized or when the storage unit is regularly updated. 【請求項７】 電圧設定手段は、増幅手段のゲインが変
更されていれば基準電圧の設定動作を行う請求項１また
は２記載の流量計測装置。7. The flow rate measuring device according to claim 1, wherein the voltage setting means performs a reference voltage setting operation if the gain of the amplifying means is changed. 【請求項８】 電圧設定手段は、流量算出手段により算
出した流量の変化に応じて基準電圧を更新する請求項１
または２記載の流量計測装置。8. The voltage setting means updates the reference voltage according to a change in the flow rate calculated by the flow rate calculating means.
Or the flow rate measuring device according to 2. 【請求項９】 流体の温度を算出する温度算出部を備
え、電圧設定手段は、流体の温度が一定以上変化するご
とに基準電圧の設定動作を行う請求項１または２記載の
流量計測装置。9. The flow rate measuring device according to claim 1, further comprising a temperature calculation unit that calculates the temperature of the fluid, and the voltage setting unit performs the setting operation of the reference voltage each time the temperature of the fluid changes by a certain amount or more. 【請求項１０】 流体管路に設けられ超音波信号を送受
信する第１振動子及び第２振動子を送信手段で駆動し、
受信側の振動子の受信信号を増幅手段で増幅し、電圧設
定手段が基準電圧を出力して、前記増幅手段で増幅され
た信号と基準電圧とを基準比較手段が比較し、前記基準
比較手段の出力と前記増幅手段出力とから判定手段が超
音波の到達ポイントを判定する流量計測方法において、
前記電圧設定手段は、増幅手段の出力のピーク電圧に対
し所定の比率の基準電圧を出力して、前記基準比較手段
の出力と前記判定手段からの出力との時間差または超音
波の伝搬時間に基づいて基準電圧を設定する流量計測方
法。10. A first oscillator and a second oscillator, which are provided in the fluid conduit and which transmit and receive ultrasonic signals, are driven by a transmitting means,
The received signal of the transducer on the receiving side is amplified by the amplifying means, the voltage setting means outputs the reference voltage, and the reference comparing means compares the signal amplified by the amplifying means with the reference voltage. In the flow rate measuring method in which the determining means determines the arrival point of the ultrasonic wave from the output of the
The voltage setting means outputs a reference voltage of a predetermined ratio with respect to the peak voltage of the output of the amplifying means, based on the time difference between the output of the reference comparing means and the output of the judging means or the propagation time of ultrasonic waves. Flow rate measurement method to set the reference voltage by using.
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