JP2001004419A - Flowmeter - Google Patents

Flowmeter

Info

Publication number
JP2001004419A
JP2001004419A JP11177952A JP17795299A JP2001004419A JP 2001004419 A JP2001004419 A JP 2001004419A JP 11177952 A JP11177952 A JP 11177952A JP 17795299 A JP17795299 A JP 17795299A JP 2001004419 A JP2001004419 A JP 2001004419A
Authority
JP
Japan
Prior art keywords
measurement
time
fluctuation
flow rate
detecting means
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.)
Granted
Application number
JP11177952A
Other languages
Japanese (ja)
Other versions
JP4556253B2 (en
Inventor
Yasuhiro Umekage
康裕 梅景
Yukio Nagaoka
行夫 長岡
Hideji Abe
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 Holdings Corp
Original Assignee
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
Priority to JP17795299A priority Critical patent/JP4556253B2/en
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to CNB2006101684850A priority patent/CN100545588C/en
Priority to CN2006101058560A priority patent/CN1912552B/en
Priority to CN2008100032863A priority patent/CN101266159B/en
Priority to AU55693/00A priority patent/AU5569300A/en
Priority to CNB2004100947648A priority patent/CN100501345C/en
Priority to US10/019,418 priority patent/US6796189B1/en
Priority to PCT/JP2000/004165 priority patent/WO2001001081A1/en
Priority to KR10-2001-7016609A priority patent/KR100487690B1/en
Priority to CN2007101099584A priority patent/CN101074885B/en
Priority to CNB00809439XA priority patent/CN1293369C/en
Priority to EP00940829A priority patent/EP1243901A4/en
Publication of JP2001004419A publication Critical patent/JP2001004419A/en
Priority to US10/711,053 priority patent/US6915704B2/en
Priority to US10/711,054 priority patent/US6941821B2/en
Priority to US10/711,055 priority patent/US7082841B2/en
Application granted granted Critical
Publication of JP4556253B2 publication Critical patent/JP4556253B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To measure stably and precisely a flow rate value when change is generated, by detecting change information and performing measurement when the flow rate of gas or liquid having flow rate change or pressure change is measured. SOLUTION: This flowmeter is equipped with a flow rate detecting means 28 detecting a flow rate by measuring the propagation time of a sound wave transmitted and received by a first vibrating means 23 and a second vibrating means 25 which transmit and receive the sound wave, a change detecting means 29 measuring pressure change in a flow channel with at least one out of the first and second vibrating means 23 and 25, and a measurement controlling means 30 beginning measurement synchronously with the timing of pressure change of the change detecting means. Thereby a pressure sensor is made unnecessary, miniaturization and simplification of a flow channel are enabled, and a flow rate can be measured stably in a short time when pressure change is generated.

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、液体や気体の流量
を計測する流量計測装置に関し、流量変動が発生した場
合にも精度よく流量値を計測する手段に関するものであ
る。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate measuring device for measuring a flow rate of a liquid or a gas, and more particularly to a means for accurately measuring a flow rate value even when a flow rate fluctuation occurs.

【0002】[0002]

【従来の技術】従来、この種の流量計は、特開平9−1
5006号公報や特開平11−44563号公報のよう
なものが知られていた。以下、その構成について図16
と図17を参照しながら説明する。
2. Description of the Related Art Conventionally, this type of flow meter is disclosed in
Japanese Patent Application Laid-Open No. 5006 and Japanese Patent Application Laid-Open No. 11-44563 have been known. The configuration is described below with reference to FIG.
This will be described with reference to FIG.

【0003】図16に示すように、ガス流量を計測する
アナログフローセンサ1から所定の第1サンプリング時間
毎に計測値を読み取るサンプリングプログラム2と、所
定時間におけるガス消費流量を算出するガス消費量算出
プログラム3と、第1サンプリング時間に所定時間内で
第2サンプリング時間毎にアナログフローセンサの計測
値を読み出してその平均値を演算する平均値演算プログ
ラム4と、フローセンサの出力から圧力変動の周期を推
定する圧力変動周期推定プログラム5と、メモリーとし
てのRAM6で構成されていた。ここで、7は前記各プ
ログラムを記憶しておくメモリーのROM、8はそのプ
ログラムを実行するCPUである。この構成により、所
定計測時間がポンプの振動周期の1周期以上、またはそ
の周期の倍数であるように計測処理するものであり、平
均化することで流量に変動が発生しても計測流量が影響
されにくい構成としている。
As shown in FIG. 16, a sampling program 2 for reading a measurement value from an analog flow sensor 1 for measuring a gas flow rate at every predetermined first sampling time, and a gas consumption calculation for calculating a gas consumption flow rate for a predetermined time. A program 3, an average value calculation program 4 for reading a measured value of the analog flow sensor every second sampling time within a predetermined time within the first sampling time and calculating an average value thereof, and a cycle of pressure fluctuation from an output of the flow sensor. And a RAM 6 as a memory. Here, 7 is a ROM of a memory for storing the programs, and 8 is a CPU for executing the programs. With this configuration, the measurement process is performed so that the predetermined measurement time is at least one cycle of the vibration cycle of the pump or a multiple of the cycle. Even if the flow rate fluctuates due to averaging, the measured flow rate is affected. It is configured to be difficult to perform.

【0004】また、図17に示すように、流量を検出す
る流量検出手段9と、流体の変動波形を検出する変動検
出手段10と、流量検出手段の測定を変動波形の交流成
分のゼロ付近で開始する脈動計測手段11と、流量検出
手段の信号を処理する流量演算手段12を備えた構成で
ある。ここで、13は信号処理回路、14は計時回路、
15はトリガ回路、16は送信回路、17は比較回路、
18は増幅回路、19は切換器、20は計測開始信号回
路、21は起動手段、22は流路である。この構成によ
り、変動波形の平均付近の流量を計測して短時間に正確
な流量計測を行うものである。
As shown in FIG. 17, a flow rate detecting means 9 for detecting a flow rate, a fluctuation detecting means 10 for detecting a fluctuation waveform of a fluid, and a measurement of the flow rate detecting means are performed near zero of an AC component of the fluctuation waveform. The configuration includes a pulsation measuring unit 11 to be started and a flow rate calculating unit 12 for processing a signal of the flow rate detecting unit. Here, 13 is a signal processing circuit, 14 is a clock circuit,
15 is a trigger circuit, 16 is a transmission circuit, 17 is a comparison circuit,
Reference numeral 18 denotes an amplification circuit, 19 denotes a switch, 20 denotes a measurement start signal circuit, 21 denotes a starting unit, and 22 denotes a flow path. With this configuration, the flow rate around the average of the fluctuation waveform is measured, and accurate flow rate measurement is performed in a short time.

【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
技術では、第1の引例では、平均値を用いてガス流量を
計測するもので、安定した平均値を得るには長時間の計
測が必要で、瞬時の流量計測は困難という課題があっ
た。また、第2の引例では、圧力変動のある無しで流量
計測の方法を変えるもので、圧力計測手段および流量計
測手段の2つの手段を備えなければならないという課題
があった。
However, in the above-mentioned prior art, in the first reference, the gas flow rate is measured using the average value, and a long time measurement is required to obtain a stable average value. There was a problem that instantaneous flow rate measurement was difficult. Further, in the second reference, the method of measuring the flow rate is changed without pressure fluctuation, and there is a problem that two means of the pressure measuring means and the flow rate measuring means must be provided.

【0006】[0006]

【課題を解決するための手段】本発明は上記課題を解決
するために、流路に設けられて音波を送受信する送受信
手段と、前記送受信手段で送受信される音波の伝搬時間
を計測する計時手段と、前記計時手段の値に基づいて流
量を検出する流量検出手段と、前記送受信手段で流路内
の変動を計測する変動検出手段と、前記変動検出手段の
変動のタイミングに同期して計測を開始する計測制御手
段とを備えた構成とした。
According to the present invention, there is provided a transmitting / receiving means provided in a flow path for transmitting / receiving a sound wave, and a time measuring means for measuring a propagation time of the sound wave transmitted / received by the transmitting / receiving means. And, a flow rate detecting means for detecting a flow rate based on the value of the time measuring means, a fluctuation detecting means for measuring a fluctuation in the flow path by the transmitting and receiving means, and a measurement synchronized with a fluctuation timing of the fluctuation detecting means. And a control unit for starting the measurement.

【0007】上記発明によれば、第1振動手段および第
2振動手段の少なくとも一方で流路内の変動を計測する
ことができるので、変動検出用の別センサを設ける必要
がなく、小型化や流路などを簡素化することができると
ともに変動が発生した場合でも短時間で安定して精度よ
く流量が計測できる。
According to the above invention, the fluctuation in the flow path can be measured in at least one of the first vibrating means and the second vibrating means, so that it is not necessary to provide another sensor for detecting fluctuation, and it is possible to reduce the size and the size. The flow path and the like can be simplified, and even when a change occurs, the flow rate can be measured stably and accurately in a short time.

【0008】[0008]

【発明の実施の形態】本発明は、流路に設けられて音波
を送受信する送受信手段と、前記送受信手段で送受信さ
れる音波の伝搬時間を計測する計時手段と、前記計時手
段の値に基づいて流量を検出する流量検出手段と、前記
送受信手段で流路内の変動を計測する変動検出手段と、
前記変動検出手段の変動のタイミングに同期して計測を
開始する計測制御手段とを備えた。そして、第1振動手
段および第2振動手段の少なくとも一方で流路内の変動
を計測することができるので、変動検出用の別センサを
設ける必要がなく、小型化や流路などを簡素化すること
ができるとともに、変動が発生した場合でも短時間で安
定して精度よく流量が計測できる。
DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a transmitting / receiving means provided in a flow path for transmitting and receiving a sound wave, a time measuring means for measuring a propagation time of a sound wave transmitted and received by the transmitting / receiving means, and a value based on the value of the time measuring means. Flow detecting means for detecting the flow rate, fluctuation detecting means for measuring fluctuations in the flow path in the transmitting and receiving means,
Measurement control means for starting measurement in synchronization with the timing of the fluctuation of the fluctuation detecting means. Since the fluctuation in the flow path can be measured in at least one of the first vibration means and the second vibration means, there is no need to provide another sensor for detecting fluctuation, and the size and the flow path are simplified. In addition, the flow rate can be measured stably and accurately in a short time even when the fluctuation occurs.

【0009】また、流路に設けられて音波を送受信する
第1振動手段および第2振動手段と、前記第1振動手段
および第2振動手段の送受信の動作を切換える切換手段
と、前記第1振動手段および第2振動手段の少なくとも
一方で流路内の圧力変動を検出する変動検出手段と、前
記第1振動手段および第2振動手段で送受信される音波
の伝搬時間を計測する計時手段と、前記変動検出手段の
出力が所定変化した時に流路の上流側の第1振動手段か
ら下流側の第2振動手段に伝搬する第1計時時間T1を
前記計時手段が測定し、また、前記変動検出手段の出力
が前記所定変化と逆に変化した時には流路の下流側の第
2振動手段から上流側の第1振動手段に伝搬する第2計
時時間T2を前記計時手段が測定する制御を行う計測制
御手段と、前記第1計時時間T1と前記第2計時時間T2
を用いて流量を算出する流量検出手段とを備えた構成と
した。そして、圧力変動の変化が逆になるタイミングで
計測することで、圧力変動と計測するタイミングの位相
をずらすことができ、圧力変動による計測誤差を相殺す
ることができる。
A first vibrating means and a second vibrating means provided in the flow path for transmitting and receiving a sound wave; a switching means for switching the transmitting and receiving operations of the first vibrating means and the second vibrating means; A fluctuation detecting means for detecting a pressure fluctuation in the flow path of at least one of the means and the second vibrating means; a time measuring means for measuring a propagation time of a sound wave transmitted and received by the first vibrating means and the second vibrating means; When the output of the fluctuation detecting means changes by a predetermined amount, the time measuring means measures a first time T1 which propagates from the first vibrating means on the upstream side of the flow path to the second vibrating means on the downstream side, and the fluctuation detecting means When the output of the first time changes in reverse to the predetermined change, the time measuring means controls the second time measuring time T2 propagating from the second vibrating means on the downstream side of the flow path to the first vibrating means on the upstream side. Means and the first total Time said the T1 second measured time T2
And a flow rate detecting means for calculating a flow rate by using the above. The measurement is performed at the timing when the change in the pressure fluctuation is reversed, so that the phase of the pressure fluctuation and the timing of the measurement can be shifted, and the measurement error due to the pressure fluctuation can be canceled.

【0010】また、変動検出手段の出力が所定変化した
時に第1計時時間T1の測定を開始し、前記変動検出手
段の出力が前記所定変化と逆に変化した時に第2計時時
間T2の測定を開始する計測制御と、次回の計測時は、
変動検出手段の出力が前記所定変化と逆に変化した時に
第1計時時間T1の測定を開始し、前記変動検出手段の
出力が所定変化した時に第2計時時間T2の測定を開始
計測制御を行う計測制御手段と、計測開始を交互に変更
しながら前回の第1計時時間T1と第2計時時間T2を用
いて求めた第1流量と、次回の第1計時時間T1と第2計
時時間T2を用いて求めた第2流量を逐次平均処理する
ことにより流量を算出する流量検出手段を備えた構成と
した。そして、計測するタイミングを前述のように変え
て第1計時時間T1と第2計時時間T2することで、圧力
変動が高圧側、低圧側で非対称となっていても、その圧
力変動の影響を相殺することができる。
When the output of the fluctuation detecting means changes by a predetermined amount, the measurement of the first clocking time T1 is started, and when the output of the fluctuation detecting means changes in a direction opposite to the predetermined change, the measurement of the second clocking time T2 is started. At the start of measurement control and the next measurement,
When the output of the fluctuation detecting means changes in reverse to the predetermined change, the measurement of the first clock time T1 is started, and when the output of the fluctuation detecting means changes by the predetermined time, the measurement of the second clock time T2 is started. The measurement control means and the first flow rate obtained by using the previous first time measurement time T1 and the second time measurement time T2 while alternately changing the measurement start, and the next first time measurement time T1 and second time measurement time T2. The flow rate detecting means for calculating the flow rate by successively averaging the second flow rates obtained by using the above-mentioned configuration is provided. By changing the measurement timing as described above and performing the first time measurement time T1 and the second time measurement time T2, even if the pressure fluctuation is asymmetric on the high pressure side and the low pressure side, the influence of the pressure fluctuation is offset. can do.

【0011】また、音波による送受信を複数回行う繰返
手段を備えた構成とした。そして、計測回数を増加する
ことで平均化することができ、安定した流量計測を行う
ことができる。
Further, the apparatus is provided with a repetition means for performing transmission and reception by a sound wave a plurality of times. Then, averaging can be performed by increasing the number of times of measurement, and stable flow rate measurement can be performed.

【0012】また、変動周期の整数倍時間にわたって送
受信を複数回行う繰返手段を備えた構成とした。そし
て、変動周期で計測することで圧力変動が平均化され安
定した流量を計測することができる。
Further, the apparatus is provided with a repetition means for performing transmission and reception a plurality of times over an integral multiple of the fluctuation period. The pressure fluctuation is averaged by measuring in a fluctuation cycle, and a stable flow rate can be measured.

【0013】また、変動検出手段の出力が所定変化した
時に音波の送受信計測を開始し、前記変動検出手段の出
力が前記所定変化と同じ変化をするまで繰返し音波の送
受信計測を行う繰返手段を備えた。そして、計測の開始
と停止を圧力変動の周期と一致させることができるの
で、変動周期で計測することができ圧力変動が平均化さ
れ安定した流量を計測することができる。
[0013] Further, a repetition means for starting transmission / reception measurement of sound waves when the output of the fluctuation detection means changes by a predetermined amount, and repeatedly performing transmission / reception measurement of sound waves until the output of the fluctuation detection means changes in the same manner as the predetermined change. Equipped. Since the start and the stop of the measurement can be made to coincide with the cycle of the pressure fluctuation, the measurement can be performed at the fluctuation cycle, and the pressure fluctuation can be averaged and a stable flow rate can be measured.

【0014】また、第1振動手段および第2振動手段
を、音波の送受信に用いる場合と、圧力変動の検出に用
いる場合を切換える選択手段を備えた構成とした。そし
て、第1振動手段および第2振動手段の少なくとも1方
を圧力検出に使用することができ、流量計測と圧力計測
を両立することができる。
Further, the first vibration means and the second vibration means are provided with a selection means for switching between a case where the first vibration means is used for transmitting and receiving sound waves and a case where the first vibration means is used for detecting pressure fluctuation. Then, at least one of the first vibrating means and the second vibrating means can be used for pressure detection, and both flow rate measurement and pressure measurement can be achieved.

【0015】また、圧力変動波形の交流成分のゼロ付近
を検出する変動検出手段を備えた構成とした。そして、
圧力変動のゼロ成分付近で変動を検出することで流量計
測を行う時間の範囲が変動ゼロ付近から計測を開始する
ことができ、変動の少ない時間内に流量計測を行うこと
で圧力変動時の計測を安定化することができる。
Further, the apparatus is provided with fluctuation detecting means for detecting the vicinity of zero of the AC component of the pressure fluctuation waveform. And
By detecting the fluctuation near the zero component of the pressure fluctuation, the time range for the flow rate measurement can be started from near the fluctuation zero, and the measurement at the time of the pressure fluctuation can be started by measuring the flow rate within the time where the fluctuation is small. Can be stabilized.

【0016】また、変動検出手段の出力信号の変動をカ
ウントする複数ビットのカウント手段と、前記カウント
手段のカウント値が、第1計時と第2計時で異なるように
して計測し、複数ビットのすべての組み合わせが同じ回
数だけ実現した時に流量を計測する流量検出手段を備え
た構成とした。そして、すべての変動タイミングで計測
することができるので、平均化が行われ安定して流量を
計測することができる。
Further, a plurality of bits of counting means for counting the variation of the output signal of the variation detecting means, and counting is performed such that the count value of the counting means is different between the first time and the second time, and all of the plurality of bits are measured. The configuration provided with a flow rate detecting means for measuring the flow rate when the same combination is realized the same number of times. Since the measurement can be performed at all the fluctuation timings, the averaging is performed and the flow rate can be stably measured.

【0017】また、変動検出手段の信号の周期を検出す
る周期検出手段と、前記周期検出手段の検出した周期
が、所定の周期の時にのみ計測を開始する計測制御手段
を備えた構成とした。そして、所定周期の時のみに計測
を開始することで、所定の変動時に計測が行え、安定し
た流量を計測することができる。
[0017] Further, the apparatus is provided with a cycle detecting means for detecting a cycle of a signal of the fluctuation detecting means, and a measuring control means for starting measurement only when the cycle detected by the cycle detecting means is a predetermined cycle. Then, by starting the measurement only at the predetermined period, the measurement can be performed at the time of the predetermined fluctuation, and the stable flow rate can be measured.

【0018】また、変動検出手段の信号が検出できなか
った時は、所定時間後に計測を自動的にスタートする検
出解除手段を備えた構成とした。そして、変動がなくな
った場合でも所定時間がくれば自動的に流量を計測する
ことができる。
In addition, when a signal from the fluctuation detecting means cannot be detected, a detection canceling means for automatically starting measurement after a predetermined time is provided. Then, even if there is no fluctuation, the flow rate can be automatically measured after a predetermined time.

【0019】また、第1振動手段および第2振動手段
は、圧電式振動子からなる構成とした。そして、圧電式
振動子とすることで超音波を送受信に用いながら、かつ
圧力変動も検出することができる。
The first vibrating means and the second vibrating means are constituted by piezoelectric vibrators. By using a piezoelectric vibrator, pressure fluctuation can be detected while using ultrasonic waves for transmission and reception.

【0020】[0020]

【実施例】以下、本発明の実施例について図面を参照し
て説明する。
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の流
量計のブロック図である。図1において、23は流路2
4に設けられて超音波を送受信する送受信手段の第1振
動手段としての第1圧電振動子、25は超音波を送受信
する送受信手段の第2振動手段としての第2圧電振動
子、26は前記第1圧電振動子および第2圧電振動子の
送受信の動作を切換える切換手段としての切換スイッ
チ、27は前記第1圧電振動子23および第2圧電振動
子25で繰返し送受信される音波の伝搬時間をシングア
ラウンド法により計測する計時手段、28は前記計時手
段の値に基づいて流量を検出する流量検出手段、29は
前記第1圧電振動子23および第2圧電振動子25で流
路内の圧力変動を計測する変動検出手段、30は前記変
動検出手段の圧力変動のタイミングに同期して計測を開
始する計測制御手段である。
(Embodiment 1) FIG. 1 is a block diagram of a flow meter according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 23 denotes a channel 2
4, a first piezoelectric vibrator as a first vibrating means of a transmitting / receiving means for transmitting / receiving ultrasonic waves, a second piezoelectric vibrator as a second vibrating means of a transmitting / receiving means for transmitting / receiving ultrasonic waves, and 26 A changeover switch 27 as a switching means for switching the transmission / reception operation of the first piezoelectric vibrator and the second piezoelectric vibrator. The switch 27 sets the propagation time of the sound wave repeatedly transmitted and received by the first piezoelectric vibrator 23 and the second piezoelectric vibrator 25. Time measuring means for measuring by the sing-around method, 28 is a flow rate detecting means for detecting a flow rate based on the value of the time measuring means, 29 is the first piezoelectric vibrator 23 and the second piezoelectric vibrator 25 for pressure fluctuation in the flow path. Is a measurement control unit that starts measurement in synchronization with the pressure fluctuation timing of the fluctuation detection unit.

【0022】ここで、計測制御手段30は、変動検出手
段29の出力の立上り時に第1計時時間T1の測定を開
始し、前記変動検出手段29の出力の立ち下がり時に第
2計時時間T2の測定を開始する計測制御と、次回の計
測時は、変動検出手段の出力が立ち下がり時に第1計時
時間T1の測定を開始し、前記変動検出手段の出力が立
上り時に第2計時時間T2の測定を開始計測制御を行
い、流量計測手段28は、計測開始を交互に変更しなが
ら前回の第1計時時間T1と第2計時時間T2を用いて求
めた第1流量と、次回の第1計時時間T1と第2計時時間
T2を用いて求めた第2流量を逐次平均処理することに
より流量を算出する構成とした。そして、31は第2圧
電振動子を超音波の送受信を行うか圧力変動を検出する
かを選択する選択手段としての選択スイッチ、32は超
音波信号の送信器、33は超音波信号の受信器、34は
シングアラウンド計測を行う繰返手段、35は第1圧電
振動子と第2圧電振動子の動作チェック手段である。
Here, the measurement control means 30 starts measuring the first clocking time T1 when the output of the fluctuation detecting means 29 rises, and starts measuring the first time T1 when the output of the fluctuation detecting means 29 falls.
(2) Measurement control for starting measurement of the clocking time T2, and for the next measurement, measurement of the first clocking time T1 is started when the output of the fluctuation detecting means falls, and second measurement is performed when the output of the fluctuation detecting means rises. The measurement of the clocking time T2 is started and measurement control is performed. The flow rate measuring means 28 changes the first flow rate obtained by using the previous first clocking time T1 and the second clocking time T2 while alternately changing the measurement start and the next flow rate. The flow rate is calculated by sequentially averaging the second flow rate obtained by using the first clock time T1 and the second clock time T2. Reference numeral 31 denotes a selection switch as selection means for selecting whether to transmit / receive ultrasonic waves to the second piezoelectric vibrator or to detect pressure fluctuation, 32 denotes an ultrasonic signal transmitter, and 33 denotes an ultrasonic signal receiver. , 34 are repetition means for performing sing-around measurement, and 35 is operation check means for the first piezoelectric vibrator and the second piezoelectric vibrator.

【0023】次に動作、作用について図2から図7を用
いて説明する。図2のような構成の流路において、第1
圧電振動子23から第2圧電振動子25に向かって伝搬
する時間T1を計測すると、T1=L/(C+Vcos
θ)となる。また、第2圧電振動子25から第1圧電振
動子23に向かって伝搬する時間T2を計測すると、T
2=L/(C−Vcosθ)となる。ここで、Vは流路
内の流速、Cは音速、θは傾斜角度である。そして、T
1とT2の逆数の差をとると、次式のようにしてT1、
T2から流速Vが求まる。
Next, the operation and operation will be described with reference to FIGS. In the flow path configured as shown in FIG.
When the time T1 for propagation from the piezoelectric vibrator 23 to the second piezoelectric vibrator 25 is measured, T1 = L / (C + Vcos)
θ). When the time T2 for propagation from the second piezoelectric vibrator 25 to the first piezoelectric vibrator 23 is measured,
2 = L / (C−Vcos θ). Here, V is the flow velocity in the flow channel, C is the speed of sound, and θ is the inclination angle. And T
Taking the difference between the reciprocals of 1 and T2 gives T1,
The flow velocity V is obtained from T2.

【0024】1/T1−1/T2=2Vcosθ/L V=(L/2cosθ)・(1/T1−1/T2) ここで、流路内に圧力変動があると、その圧力変動に応
じて流速が変化する。よって、変動周波数f、変動流速
uとすると、T1、T2は T1=L/(C+Vcosθ+u・sin(2πf
t)) T2=L/(C−Vcosθ−u・sin(2πft+
ψ)) となる。ここで、ψは、T1計測の開始とT2計測の開
始の時間差(位相差)である。そして、T1とT2の逆
数の差をとると、 1/T1−1/T2=(2Vcosθ+u・(sin
(2πft)+sin(2πft+ψ)))/L であるから、ψ=πのとき、sin(2πft+ψ))
=−sin(2πft)となり、変動の影響は、キャン
セルされることになる。よって、 V=(L/2cosθ)・(1/T1−1/T2) として、変動時においても流速Vが計測でき、流路の断
面積などを考慮して流量を算出することができるのであ
る。以上は、1回の送受信の計測で説明しているが、繰
返手段34で伝搬時間を繰り返して計測するシングアラ
ウンド手法で積算時間を求める場合も同様に次式のよう
に求めることができる。
1 / T1-1 / T2 = 2Vcosθ / LV V = (L / 2cosθ) ・ (1 / T1-1 / T2) Here, if there is a pressure fluctuation in the flow path, The flow rate changes. Therefore, assuming a fluctuating frequency f and a fluctuating flow velocity u, T1 and T2 are as follows: T1 = L / (C + Vcos θ + u · sin (2πf
t)) T2 = L / (C−Vcos θ−u · sin (2πft +
ψ)). Here, ψ is a time difference (phase difference) between the start of the T1 measurement and the start of the T2 measurement. Then, by taking the reciprocal difference between T1 and T2, 1 / T1-1 / T2 = (2Vcos θ + u · (sin
Since (2πft) + sin (2πft + ψ))) / L, when ψ = π, sin (2πft + ψ))
= −sin (2πft), and the influence of the fluctuation is cancelled. Therefore, assuming that V = (L / 2 cos θ) · (1 / T1-1 / T2), the flow velocity V can be measured even in the case of fluctuation, and the flow rate can be calculated in consideration of the cross-sectional area of the flow path and the like. . Although the above description has been given of the measurement of one transmission / reception, the integration time can also be obtained by the following formula in the case where the integration time is obtained by the sing-around method of repeatedly measuring the propagation time by the repeating means 34.

【0025】 T1=Σ[L/(C+Vcosθ+u・sin(2πfti))] =ΣL/(Σ(C+Vcosθ)+Σ(u・sin(2πfti))) T2=Σ[L/(C−Vcosθθ−u・sin(2πfti+ψ))] =ΣL/(Σ(C+Vcosθ)+Σ(u・sin(2πfti+ψ))) ここで、添え字iはシングアラウンドの回数、Σはi=
1からN回までの積算を示す。なお、シングアラウンド
手法の計測処理についての詳細な説明は略すが、超音波
の送受信伝搬を繰返し行い、トータルの伝搬時間を長く
して計測精度を高める方法である。
T1 = Σ [L / (C + Vcosθ + u · sin (2πfti))] = ΣL / (Σ (C + Vcosθ) + Σ (u · sin (2πfti))) T2 = Σ [L / (C−Vcosθθ-u · sin) (2πfti + ψ))] == L / (Σ (C + Vcosθ) + Σ (u · sin (2πfti + ψ))) where subscript i is the number of sing-arounds and Σ is i =
Shows the integration from 1 to N times. Although a detailed description of the measurement processing of the sing-around method is omitted, this method is a method of repeating transmission and reception of ultrasonic waves to increase the total propagation time and increase measurement accuracy.

【0026】そして、T1、T2の逆数差から 1/T1−1/T2=(Σ[2Vcosθ]+Σ[u・
(sin(2πft))+Σ[u・sin(2πft+
ψ))])/ΣL そして、ψ=πのとき、sin(2πft+ψ))=−
sin(2πft)となり、シングアラウンド手法を用
いても変動の影響は、キャンセルされることになる。よ
って、 V=(L/2cosθ)・(1/T1−1/T2) として、変動時においても流速Vが計測でき、流路の断
面積などを考慮して流量を算出することができるのであ
る。
From the reciprocal difference between T1 and T2, 1 / T1-1 / T2 = ({[2Vcos θ] + {[u ·
(Sin (2πft)) + Σ [u · sin (2πft +
ψ))]) / ΣL And when ψ = π, sin (2πft + ψ)) = −
sin (2πft), and the influence of the fluctuation is canceled even if the sing-around method is used. Therefore, assuming that V = (L / 2 cos θ) · (1 / T1-1 / T2), the flow velocity V can be measured even in the case of fluctuation, and the flow rate can be calculated in consideration of the cross-sectional area of the flow path and the like. .

【0027】ここで、この時間差ψがπとなる計測の開
始タイミングを、図3で説明する。変動検出手段29の
出力信号は、圧力変動の交流成分のゼロクロス点を比較
器で比較して検出することによって実現している。すな
わち、T1計測の開始は、変動検出手段の出力信号の立
上りで行い、所定のシングアラウンド回数で積算時間T
1を計測する。一方、T2計測の開始は、変動検出手段
29の出力信号の立下がりで行い、同じ所定のシングア
ラウンド回数で積算時間T2を計測する。図3で示す
と、T1は、圧力波形のA、B、C間を計測し、T2は
A、B、Cと逆の振幅になるF、G、H間を計測する。
よって、圧力変動はキャンセルされることになる。
Here, the start timing of measurement at which the time difference と becomes π will be described with reference to FIG. The output signal of the fluctuation detecting means 29 is realized by comparing and detecting the zero cross point of the AC component of the pressure fluctuation with a comparator. That is, the measurement of T1 is started at the rise of the output signal of the fluctuation detecting means, and the integration time T is calculated at a predetermined number of sing-around times.
Measure 1. On the other hand, the start of T2 measurement is performed at the fall of the output signal of the fluctuation detecting means 29, and the integrated time T2 is measured at the same predetermined number of sing-arounds. As shown in FIG. 3, T1 measures between A, B, and C of the pressure waveform, and T2 measures between F, G, and H having amplitudes opposite to those of A, B, and C.
Therefore, the pressure fluctuation is canceled.

【0028】また、図3のような正負対称の圧力変動の
場合は、1回のT1とT2の計測でキャンセルできる
が、図4のような正負非対称の場合は、計測の開始を工
夫することによってキャンセルすることができる。すな
わち、T1計測の開始は、変動検出手段29の出力信号
の立上りで行い、所定のシングアラウンド回数で積算時
間T1を計測する。一方、T2計測の開始は、変動検出
手段29の出力信号の立下がりで行い、同じ所定のシン
グアラウンド回数で積算時間T2を計測する。そして、
次回の計測では、T1計測の開始は、変動検出手段29
の出力信号の立下がりで行い、所定のシングアラウンド
回数で積算時間T1を計測する。一方、T2計測の開始
は、変動検出手段29の出力信号の立上がりで行い、同
じ所定のシングアラウンド回数で積算時間T2を計測す
る。図4で示すと、1回目のT1は、圧力波形のA、
B、C間を計測し、T2はD、E、F間を計測する。こ
れでは、CとFは波形が異なるのでCとFの分が誤差C
−(−F)として残るが、2回目の計測の時には、T1
は、逆波形のH、I、Jで計測し、T2はK、L、Mで
計測する。ここでも、JとMは波形が異なり誤差として
残るが、2回目の計測では、上流側から計測した時のM
と、下流から計測した時のJとなっており、符号が反転
するので、JとMの分が誤差(−J−M)として残る。
そして、C=M、F=Jであることから、C−(−F)
と(−J−M)を加算して平均を取ると、ゼロになり、
圧力変動はキャンセルされることになる。なお、超音波
の送受信の方向を計測のたびに交互に反転している場合
は、計測の開始タイミングは一定でよいことは明白であ
る。また、ここでは2回の計測で説明したが、圧力変動
の波形が非対称で複雑な場合は、計測の開始を波形の周
期性に応じて順次、変更して繰返すことにより平均化さ
れ、誤差は最小限に抑えることができる。
In addition, in the case of a positive-negative symmetric pressure fluctuation as shown in FIG. 3, the measurement can be canceled by one measurement of T1 and T2. However, in the case of a positive-negative asymmetric as shown in FIG. Can be canceled by That is, the T1 measurement is started at the rising edge of the output signal of the fluctuation detecting means 29, and the integrated time T1 is measured at a predetermined number of sing-arounds. On the other hand, the start of T2 measurement is performed at the fall of the output signal of the fluctuation detecting means 29, and the integrated time T2 is measured at the same predetermined number of sing-arounds. And
In the next measurement, the start of the T1 measurement is determined by the fluctuation detecting means 29.
And the integration time T1 is measured at a predetermined number of sing-arounds. On the other hand, T2 measurement is started at the rise of the output signal of the fluctuation detecting means 29, and the integrated time T2 is measured at the same predetermined number of sing-arounds. As shown in FIG. 4, the first T1 is A,
B and C are measured, and T2 is measured between D, E and F. In this case, since the waveforms of C and F are different, the difference between C and F is the error C
− (− F), but at the time of the second measurement, T1
Is measured by H, I, and J of the reverse waveform, and T2 is measured by K, L, and M. Again, the waveforms of J and M are different and remain as errors, but in the second measurement, M
And J when measured from the downstream, and the sign is inverted, so that J and M remain as an error (−J−M).
Then, since C = M and F = J, C − (− F)
And (−J−M) are added and averaged, it becomes zero,
The pressure fluctuation will be canceled. When the direction of transmission and reception of ultrasonic waves is alternately inverted every time measurement is performed, it is apparent that the measurement start timing may be constant. In addition, although the description has been given of two measurements here, when the waveform of the pressure fluctuation is asymmetric and complicated, the start of the measurement is averaged by sequentially changing and repeating the start of the measurement according to the periodicity of the waveform, and the error is reduced. Can be minimized.

【0029】次に、図5と図6のフローチャートを用い
て計測の流れを説明する。まず、変動検出手段の信号が
立上りか否かを判別する。立上りでなければ、変動検出
手段29の出力信号が立ち上がるまで判別を繰り返す。
ここで、所定時間立っても立上りが発生しない時は、検
出解除手段としての処理が立上り検出を中止し、圧力変
動がないものとして第1計時時間T1と第2計時時間T
2の計測を行う。また、立上りが検出された時は、第1
計時時間T1の計測を行う。そして、次に変動検出手段
29の信号が立下がりか否かを判別する。ここで立ち下
がりが検出された時は、第2計時時間T2の計測を行
う。また、所定時間立っても、立下がりが検出されない
時は、検出解除手段としての処理が立下がり検出を中止
し、圧力変動がないものとして第2計時時間T2の計測
を行い、第1計時時間T1と第2計時時間T2から流量
Q(j)を算出する。
Next, the flow of measurement will be described with reference to the flowcharts of FIGS. First, it is determined whether or not the signal of the fluctuation detecting means has risen. If it does not rise, the determination is repeated until the output signal of the fluctuation detecting means 29 rises.
Here, when the rise does not occur even after standing for a predetermined time, the processing as the detection canceling means stops the rise detection, and assuming that there is no pressure fluctuation, the first clock time T1 and the second clock time T1 are determined.
2 is measured. When a rising is detected, the first
The time T1 is measured. Then, it is determined whether or not the signal of the fluctuation detecting means 29 falls. Here, when the fall is detected, the second time T2 is measured. Also, if the fall is not detected even after standing for a predetermined time, the processing as the detection canceling means stops the fall detection, and measures the second time T2 assuming that there is no pressure fluctuation. The flow rate Q (j) is calculated from T1 and the second time T2.

【0030】そして、次の計測時には、図6に示すよう
に、今度は立下がり検出からはじめ、立下がり検出後、
第1計時時間T1の計測を行った後、立上り検出を行
い、第2計時時間T2の計測を行い、第1計時時間T1
と第2計時時間T2から流量Q(j+1)を算出する。
そして、この計測開始を交互に変更しながら繰返し、第
1流量Q(j)と第2流量Q(j+1)を計測して逐次
平均処理することにより流量Qを算出することで、平均
化され誤差を原理的になくすことができる。
At the time of the next measurement, as shown in FIG. 6, this time, the falling detection is started, and after the falling detection,
After measuring the first clock time T1, a rise is detected, a second clock time T2 is measured, and the first clock time T1 is measured.
And the second time T2, the flow rate Q (j + 1) is calculated.
The measurement start is repeated while changing the measurement alternately, and the flow rate Q is calculated by measuring the first flow rate Q (j) and the second flow rate Q (j + 1) and sequentially averaging them, thereby averaging the errors. Can be eliminated in principle.

【0031】このように、第2圧電振動子25で流路内
の圧力変動を計測することができるので、圧力センサを
設ける必要がなく、小型化や流路などを簡素化すること
ができるとともに、圧力変動が発生した場合でも瞬時流
量の計測が安定して精度よく行える。そして、圧力変動
の変化が逆になるタイミングで計測することで、圧力変
動と計測するタイミングの位相をずらすことができ、圧
力変動による計測誤差を相殺することができる。そし
て、計測する毎にタイミングを正負逆にとって行くこと
で、圧力変動が高圧側、低圧側で非対称となっていて
も、その圧力変動の影響を相殺することができる。そし
て、シングアラウンドで繰返し計測することで1回の計
測で平均化することができ、安定した流量計測を行うこ
とができる。そして、選択手段を用いることで第1振動
手段および第2振動手段の少なくとも1方を圧力検出に
使用することができ、流量計測と圧力計測を両立するこ
とができる。そして、圧力変動のゼロ成分付近で変動を
検出することで変動の周期を正確に捉えることができ、
流量の相殺が行える。そして、変動がなくなった場合で
も所定時間がくれば自動的に流量を計測することができ
る。そして、圧電式振動子を変動検出手段と用いること
で、超音波を送受信に用いながら、かつ圧力変動も検出
することができ、さらに、専用の圧力検出手段を設ける
場所が不要であり、漏洩の要因となる部位を削減するこ
とができる効果がある。
As described above, since the pressure fluctuation in the flow path can be measured by the second piezoelectric vibrator 25, there is no need to provide a pressure sensor, and the size and the flow path can be simplified. Even when pressure fluctuations occur, the instantaneous flow rate can be measured stably and accurately. The measurement is performed at the timing when the change in the pressure fluctuation is reversed, so that the phase of the pressure fluctuation and the timing of the measurement can be shifted, and the measurement error due to the pressure fluctuation can be canceled. Then, by setting the timing to be opposite for each measurement, even if the pressure fluctuation is asymmetric on the high pressure side and the low pressure side, the influence of the pressure fluctuation can be canceled. Then, by repeating the measurement in the sing-around, the measurement can be averaged in one measurement, and the stable flow measurement can be performed. By using the selecting means, at least one of the first vibrating means and the second vibrating means can be used for pressure detection, and both flow rate measurement and pressure measurement can be achieved. And by detecting the fluctuation near the zero component of the pressure fluctuation, the period of the fluctuation can be accurately grasped,
The flow rate can be offset. Then, even if there is no fluctuation, the flow rate can be automatically measured after a predetermined time. And, by using the piezoelectric vibrator as the fluctuation detecting means, it is possible to detect the pressure fluctuation while using the ultrasonic wave for transmission and reception, and further, it is not necessary to provide a dedicated pressure detecting means, and the leakage is prevented. There is an effect that a part which becomes a factor can be reduced.

【0032】なお、本実施例で説明した圧力変動の検出
は、専用の圧力検出手段を用いて行っても機能的には同
様の効果が得られる。また、下流側の第2圧電振動子を
用いる場合で説明したが、上流側の第1圧電振動子を用
いる場合でも同様の効果が得られる。さらに、上流側、
下流側の圧電振動子を交互に用いても同様の効果が得ら
れるが、交互に用いることによって、互いの圧電振動子
の動作状態をチェックすることも可能になる。すなわ
ち、変動検出手段の信号がどちらの圧電振動子からの信
号においても同じ周期の信号の時はどちらも正常に動作
していると、判定することができる。
The same effect can be obtained functionally by detecting the pressure fluctuation described in the present embodiment by using a dedicated pressure detecting means. Further, the case where the downstream second piezoelectric vibrator is used has been described, but the same effect can be obtained when the upstream first piezoelectric vibrator is used. In addition, upstream,
The same effect can be obtained by alternately using the piezoelectric vibrators on the downstream side. However, by using the piezoelectric vibrators alternately, it is also possible to check the operation state of each piezoelectric vibrator. That is, when the signal of the fluctuation detecting means is a signal of the same cycle in both of the signals from the piezoelectric vibrators, it can be determined that both are operating normally.

【0033】また、流量計は一般計器として説明してい
るが、ガスメーターに本流量計を使用することで、ガス
エンジンヒートポンプを使用している配管系など、脈動
が発生する流路配管で使用することが可能である。さら
に、圧力変動で説明しているが、流量変動のある場合も
同様の効果があることは明白である。
Although the flow meter has been described as a general instrument, the use of the present flow meter in a gas meter allows the flow meter to be used in a flow path pipe in which pulsation occurs, such as a pipe system using a gas engine heat pump. It is possible. Further, although the description has been made with reference to the pressure fluctuation, it is clear that a similar effect can be obtained even when there is a flow rate fluctuation.

【0034】(実施例2)図8は本発明の実施例2の流
量計の動作を示すタイミングチャートである。実施例1
と異なる点は、変動周期の整数倍時間にわたってシング
アラウンドの送受信を複数回行う繰返手段34を備えた
ことにある。構成は図1に示す。
(Embodiment 2) FIG. 8 is a timing chart showing the operation of a flow meter according to Embodiment 2 of the present invention. Example 1
A different point from the first embodiment is that a repetition means 34 for transmitting and receiving a sing-around a plurality of times over an integral multiple of the fluctuation period is provided. The configuration is shown in FIG.

【0035】図9に示すように、所定時間(例えば、2
秒周期)間隔で、計測を開始する場合、所定時間になれ
ば、変動検出手段29が検出する変動の周期を計測す
る。そして、その周期にほぼ一致するシングアラウンド
の回数を設定する。例えば、超音波の圧電振動子間の距
離を音速で割ると1回の伝搬時間が算出できる。そし
て、計測した周期をその伝搬時間で割ることで必要なシ
ングアラウンドの回数が算出できる。そのシングアラウ
ンド回数で繰返して流量の計測を行うのである。図中の
丸1は、図5の丸1の処理を行うことである。
As shown in FIG. 9, a predetermined time (for example, 2
When the measurement is started at intervals of a (second cycle), when a predetermined time has elapsed, the cycle of the fluctuation detected by the fluctuation detecting means 29 is measured. Then, the number of sing-arounds substantially matching the cycle is set. For example, one propagation time can be calculated by dividing the distance between the piezoelectric vibrators of ultrasonic waves by the speed of sound. Then, the number of necessary sing-arounds can be calculated by dividing the measured cycle by the propagation time. The flow rate is measured repeatedly by the number of sing-arounds. The circle 1 in the figure indicates that the processing of the circle 1 in FIG. 5 is performed.

【0036】このように、シングアラウンド回数を変動
周期に合わせることで、変動の1周期を計測することが
でき、圧力変動が平均化され安定した流量を計測するこ
とができるのである。そして、圧力同期とシングアラウ
ンド回数を周期の整数倍に合せて計測することで、更に
流量の計測を安定して行うことができる。さらに、圧力
同期を圧電振動子の信号で検出することができるので、
周期の検出が可能で、かつ安定した流量計測が行えると
いう相乗効果がある。
As described above, by adjusting the number of sing-arounds to the fluctuation cycle, one cycle of the fluctuation can be measured, and the pressure fluctuation can be averaged and a stable flow rate can be measured. By measuring the number of times of pressure synchronization and the number of sing-arounds in accordance with an integral multiple of the cycle, the flow rate can be measured more stably. Furthermore, since the pressure synchronization can be detected by the signal of the piezoelectric vibrator,
There is a synergistic effect that the period can be detected and the flow rate can be measured stably.

【0037】なお、図8では、2周期を計測する場合に
ついて示した。伝搬距離が短い場合は、計測精度を上げ
るために、所定回数以上のシングアラウンドが必要とな
るので、変動周期から求めたシングアラウンド回数がそ
の所定回数よりも小さい時は、周期の倍数になるように
シングアラウンド回数を決定するとよい。
FIG. 8 shows a case where two cycles are measured. When the propagation distance is short, sing-arounds of a predetermined number or more are required in order to increase the measurement accuracy, so when the number of sing-arounds obtained from the fluctuation cycle is smaller than the predetermined number, the sing-around is set to a multiple of the cycle. The number of sing-arounds may be determined in advance.

【0038】(実施例3)図10は本発明の実施例3の
流量計の動作を示すタイミングチャートである。実施例
1と異なる点は、変動検出手段29の出力が所定変化し
た時(例えば、立下り時)に音波の送受信計測を開始
し、前記変動検出手段の出力が前記所定変化と同じ変化
(例えば、立下り時)をするまでシングアラウンドを繰
返し、音波の送受信計測を行う繰返手段34を備えた構
成とした。構成は図1に示す。
(Embodiment 3) FIG. 10 is a timing chart showing the operation of a flow meter according to Embodiment 3 of the present invention. The difference from the first embodiment is that when the output of the fluctuation detecting means 29 changes by a predetermined amount (for example, at the time of falling), the measurement of the sound wave transmission / reception is started, and the output of the fluctuation detecting means changes by the same amount as the predetermined change (for example, (At the time of falling) and a repeating means 34 for repeating transmission and reception measurements of sound waves. The configuration is shown in FIG.

【0039】図11に示すように、計測の開始に変動検
出信号の立上りを検出し、シングアラウンドを開始す
る。そして、再度変動検出信号の信号が立ち上がった時
に、シングアラウンドを停止して第1計時時間T1を計
測する。次に、計測の開始に変動検出信号の立下りを検
出し、シングアラウンドを開始する。そして、再度変動
検出信号の信号が立ち下がった時に、シングアラウンド
を停止して第2計時時間T2を計測する。それらのT1
とT2から流量を算出するものである。
As shown in FIG. 11, the rising of the fluctuation detection signal is detected at the start of the measurement, and the sing-around is started. Then, when the fluctuation detection signal rises again, the sing-around is stopped and the first time measurement time T1 is measured. Next, at the start of measurement, the falling of the fluctuation detection signal is detected, and sing-around is started. When the signal of the fluctuation detection signal falls again, the sing-around is stopped and the second time T2 is measured. Their T1
And the flow rate is calculated from T2.

【0040】このように、計測の開始と停止を圧力変動
の周期と一致させることができるので、変動周期で計測
することができ、圧力変動が平均化され安定した流量を
計測することができる。
As described above, the start and the stop of the measurement can be made to coincide with the cycle of the pressure fluctuation. Therefore, the measurement can be performed at the fluctuation cycle, and the pressure fluctuation can be averaged and a stable flow rate can be measured.

【0041】(実施例4)図12は本発明の実施例4の
流量計を示す構成図である。実施例1と異なる点は、変
動検出手段29の出力信号の変動をカウントする2ビッ
トのカウント手段36と、前記カウント手段36のカウ
ント値が、第1計時の時と第2計時の時で異なるようにし
て計測し、2ビットのすべての組み合わせが同じ回数だ
け実現した時に流量を計測する流量検出手段28を備え
た構成とした。図13にそのタイミングチャートを示
す。
(Embodiment 4) FIG. 12 is a block diagram showing a flow meter according to Embodiment 4 of the present invention. The difference from the first embodiment is that the 2-bit counting unit 36 that counts the fluctuation of the output signal of the fluctuation detecting unit 29 and the count value of the counting unit 36 are different between the first time and the second time. The flow rate detecting means 28 is configured to measure the flow rate and measure the flow rate when all the combinations of 2 bits are realized the same number of times. FIG. 13 shows the timing chart.

【0042】図13に示すように、正負対称でかつ変動
が2周期で繰返される場合、例えば、T1計測はカウン
ト手段の出力が(1、0)で、かつ変動検出手段の出力
が立上りの時に開始し、T2計測は、その後変動検出手
段の立下りで計測が開始される。このときの計測流量を
概念的に表現して、Q(i)=(A−B+C)−(−B
+C−D)=A+Dとする。そして、次回の計測をT1
計測はカウント手段の出力が(1、1)で、かつ変動検
出手段の立下りに開始し、T2計測はその後の立上りで
開始される。このときの計測流量を概念的に表現して、
Q(i+1)=(−B+C−D)−(C−D+A)=−
A−Bとする。このように繰返して計測を行うと、Q
(i+2)=(C−D+A)−(−D+A−B)=C+
B、Q(i+3)=(−D+A−B)−(A−B+C)
=−C−Dとなる。ここで、Q(i)+Q(i+1)+
Q(i+2)+Q(i+3)=0となり、圧力変動はキ
ャンセルされることになる。また、ここでは4回の計測
で説明したが、圧力変動の波形が非対称で複雑な場合
は、計測の開始を波形の周期性に応じて順次、変更して
繰返すことにより平均化され、誤差は最小限に抑えるこ
とができる。すべての変動タイミングで計測することが
できるので、平均化が行われ安定して流量を計測するこ
とができる。
As shown in FIG. 13, when the fluctuation is repeated in two cycles with positive and negative symmetry, for example, T1 measurement is performed when the output of the counting means is (1, 0) and the output of the fluctuation detecting means is a rising edge. Then, the T2 measurement is started at the fall of the fluctuation detecting means. The measured flow rate at this time is conceptually expressed as Q (i) = (A−B + C) − (− B
+ CD) = A + D. Then, the next measurement is T1
The measurement starts when the output of the counting means is (1, 1) and the fluctuation detecting means falls, and the T2 measurement starts at the subsequent rising. The measured flow rate at this time is conceptually expressed,
Q (i + 1) = (− B + CD) − (CD + A) = −
AB. Repeated measurement in this way gives Q
(I + 2) = (CD + A)-(-D + AB) = C +
B, Q (i + 3) = (-D + AB)-(AB + C)
= −CD. Here, Q (i) + Q (i + 1) +
Q (i + 2) + Q (i + 3) = 0, and the pressure fluctuation is cancelled. Although the description has been given of four measurements here, when the waveform of the pressure fluctuation is asymmetric and complicated, the start of the measurement is averaged by sequentially changing and repeating the start of the measurement according to the periodicity of the waveform, and the error is reduced. Can be minimized. Since measurement can be performed at all fluctuation timings, averaging is performed and the flow rate can be measured stably.

【0043】(実施例5)図14は、本発明の実施例5
の流量計を示す構成図である。実施例1と異なる点は、
変動検出手段29の信号の周期を検出する周期検出手段
37と、前記周期検出手段37の検出した周期が、所定
の周期の時にのみ計測を開始する計測制御手段30を備
えた構成とした。
(Embodiment 5) FIG. 14 shows Embodiment 5 of the present invention.
FIG. 3 is a configuration diagram showing a flow meter of FIG. The difference from the first embodiment is
The cycle detecting means 37 for detecting the cycle of the signal of the fluctuation detecting means 29 and the measurement control means 30 for starting the measurement only when the cycle detected by the cycle detecting means 37 is a predetermined cycle are provided.

【0044】すなわち、図15に示すように、変動検出
手段29の信号が所定周期Tmの時のみに計測を開始す
ることで、周期が変動するような場合でも所定の変動周
期時に計測が行える。図13に示すような圧力波形の場
合でも、周期を検出すれば特定の圧力変動の時のみ、流
量を計測することができる。よって、圧力変動の周期が
変動する場合でも、安定した流量を短時間で計測するこ
とができる。なお、周期の検出は所定の時間幅(例え
ば、2ミリ秒)を持って検出することで柔軟性を持たせ
計測が途切れることなく継続される。
That is, as shown in FIG. 15, by starting the measurement only when the signal of the fluctuation detecting means 29 has the predetermined period Tm, the measurement can be performed at the predetermined fluctuation period even when the period fluctuates. Even in the case of the pressure waveform as shown in FIG. 13, if the cycle is detected, the flow rate can be measured only at a specific pressure fluctuation. Therefore, a stable flow rate can be measured in a short time even when the cycle of the pressure fluctuation is changed. The detection of the cycle is performed with a predetermined time width (for example, 2 milliseconds) so that the measurement is continued and the measurement is continued without interruption.

【0045】[0045]

【発明の効果】以上の説明から明らかなように本発明の
流量計によれば、次の効果が得られる。
As apparent from the above description, the flow meter according to the present invention has the following advantages.

【0046】本発明は、流路に設けられて音波を送受信
する送受信手段と、前記送受信手段で送受信される音波
の伝搬時間を計測する計時手段と、前記計時手段の値に
基づいて流量を検出する流量検出手段と、前記送受信手
段で流路内の圧力変動を計測する変動検出手段と、前記
変動検出手段の圧力変動のタイミングに同期して計測を
開始する計測制御手段とを備えることで、第1振動手段
および第2振動手段の少なくとも一方で流路内の圧力変
動を計測することができるので、圧力センサを設ける必
要がなく、小型化や流路などを簡素化することができる
とともに、圧力変動が発生した場合でも短時間で安定し
た流量が計測できる。
According to the present invention, there is provided transmitting / receiving means provided in a flow path for transmitting / receiving a sound wave, time-measuring means for measuring a propagation time of the sound wave transmitted / received by the transmitting / receiving means, and detecting a flow rate based on the value of the time-measuring means. Flow rate detecting means, a fluctuation detecting means for measuring pressure fluctuations in the flow path by the transmitting and receiving means, and a measurement control means for starting measurement in synchronization with the timing of pressure fluctuations of the fluctuation detecting means, Since the pressure fluctuation in the flow path can be measured in at least one of the first vibration means and the second vibration means, there is no need to provide a pressure sensor, and the size and the flow path can be simplified. Even when pressure fluctuation occurs, a stable flow rate can be measured in a short time.

【0047】また、流路に設けられて音波を送受信する
第1振動手段および第2振動手段と、前記第1振動手段
および第2振動手段の送受信の動作を切換える切換手段
と、前記第1振動手段および第2振動手段の少なくとも
一方で流路内の圧力変動を検出する変動検出手段と、前
記第1振動手段および第2振動手段で送受信される音波
の伝搬時間を計測する計時手段と、前記変動検出手段の
出力が所定変化した時に流路の上流側の第1振動手段か
ら下流側の第2振動手段に伝搬する第1計時時間T1を
前記計時手段が測定し、また、前記変動検出手段の出力
が前記所定変化と逆に変化した時には流路の下流側の第
2振動手段から上流側の第1振動手段に伝搬する第2計
時時間T2を前記計時手段が測定する制御を行う計測制
御手段と、前記第1計時時間T1と前記第2計時時間T2
を用いて流量を算出する流量検出手段とを備えること
で、圧力変動の変化が逆になるタイミングで計測するこ
とで、圧力変動と計測するタイミングの位相をずらすこ
とができ、圧力変動による計測誤差を相殺することがで
きる。
The first vibration means and the second vibration means provided in the flow path for transmitting and receiving a sound wave, the switching means for switching the transmission and reception operations of the first vibration means and the second vibration means, and the first vibration means A fluctuation detecting means for detecting a pressure fluctuation in the flow path of at least one of the means and the second vibrating means; a time measuring means for measuring a propagation time of a sound wave transmitted and received by the first vibrating means and the second vibrating means; When the output of the fluctuation detecting means changes by a predetermined amount, the time measuring means measures a first time T1 which propagates from the first vibrating means on the upstream side of the flow path to the second vibrating means on the downstream side, and the fluctuation detecting means When the output of the first time changes in reverse to the predetermined change, the time measuring means controls the second time measuring time T2 propagating from the second vibrating means on the downstream side of the flow path to the first vibrating means on the upstream side. Means and the first total Time said the T1 second measured time T2
With the flow rate detecting means for calculating the flow rate by using the pressure fluctuation, the phase of the pressure fluctuation and the timing of the measurement can be shifted by measuring at the timing when the change of the pressure fluctuation is reversed, and the measurement error due to the pressure fluctuation can be obtained. Can be offset.

【0048】また、変動検出手段の出力が所定変化した
時に第1計時時間T1の測定を開始し、前記変動検出手
段の出力が前記所定変化と逆に変化した時に第2計時時
間T2の測定を開始する計測制御と、次回の計測時は、
変動検出手段の出力が前記所定変化と逆に変化した時に
第1計時時間T1の測定を開始し、前記変動検出手段の
出力が所定変化した時に第2計時時間T2の測定を開始
計測制御を行う計測制御手段と、計測開始を交互に変更
しながら前回の第1計時時間T1と第2計時時間T2を用
いて求めた第1流量と、次回の第1計時時間T1と第2計
時時間T2を用いて求めた第2流量を逐次平均処理する
ことにより流量を算出する流量検出手段を備えたこと
で、計測するタイミングを前述のように変えて第1計時
時間T1と第2計時時間T2することで、圧力変動が高
圧側、低圧側で非対称となっていても、その圧力変動の
影響を相殺することができる。
When the output of the fluctuation detecting means changes by a predetermined amount, the measurement of the first clock time T1 is started, and when the output of the fluctuation detecting means changes in a direction opposite to the predetermined change, the measurement of the second clock time T2 is started. At the start of measurement control and the next measurement,
When the output of the fluctuation detecting means changes in reverse to the predetermined change, the measurement of the first clock time T1 is started, and when the output of the fluctuation detecting means changes by the predetermined time, the measurement of the second clock time T2 is started. The measurement control means and the first flow rate obtained by using the previous first time measurement time T1 and the second time measurement time T2 while alternately changing the measurement start, and the next first time measurement time T1 and second time measurement time T2. By providing the flow rate detecting means for calculating the flow rate by sequentially averaging the second flow rates obtained by using the above, the measurement timing is changed as described above to perform the first clock time T1 and the second clock time T2. Therefore, even if the pressure fluctuation is asymmetric on the high pressure side and the low pressure side, the influence of the pressure fluctuation can be canceled.

【0049】また、音波による送受信を複数回行う繰返
手段を備えることで、計測回数を増加することで平均化
することができ、安定した流量計測を行うことができ
る。
Further, by providing the repetition means for performing the transmission and reception by the sound wave a plurality of times, the number of times of measurement can be increased and the average can be obtained, so that the flow rate can be stably measured.

【0050】また、変動周期の整数倍時間にわたって送
受信を複数回行う繰返手段を備えることで、変動周期で
計測することで圧力変動が平均化され安定した流量を計
測することができる。
Further, by providing a repetition means for performing transmission and reception a plurality of times over an integral multiple of the fluctuation cycle, pressure fluctuations are averaged by measuring at the fluctuation cycle, and a stable flow rate can be measured.

【0051】また、変動検出手段の出力が所定変化した
時に音波の送受信計測を開始し、前記変動検出手段の出
力が前記所定変化と同じ変化をするまで繰返し音波の送
受信計測を行う繰返手段を備えることで、計測の開始と
停止を圧力変動の周期と一致させることができるので、
変動周期で計測することができ圧力変動が平均化され安
定した流量を計測することができる。
A repetition means for starting transmission / reception measurement of sound waves when the output of the fluctuation detection means changes by a predetermined amount, and repeatedly performing transmission / reception measurement of sound waves until the output of the fluctuation detection means changes in the same manner as the predetermined change. By preparing, the start and stop of measurement can be matched with the cycle of pressure fluctuation,
Measurement can be performed in a fluctuation cycle, pressure fluctuations are averaged, and a stable flow rate can be measured.

【0052】また、第1振動手段および第2振動手段
を、音波の送受信に用いる場合と、圧力変動の検出に用
いる場合を切換える選択手段を備えることで、第1振動
手段および第2振動手段の少なくとも1方を圧力検出に
使用することができ、流量計測と圧力計測を両立するこ
とができる。
Further, by providing the first vibrating means and the second vibrating means with a selecting means for switching between a case where the first vibrating means is used for transmitting and receiving a sound wave and a case where the first vibrating means is used for detecting a pressure fluctuation, the first vibrating means and the second vibrating means are provided. At least one can be used for pressure detection, and both flow measurement and pressure measurement can be achieved.

【0053】また、圧力変動波形の交流成分のゼロ付近
を検出する変動検出手段を備えることで、圧力変動のゼ
ロ成分付近で変動を検出することで流量計測を行う時間
の範囲が変動ゼロ付近から計測を開始することができ、
変動の少ない時間内に流量計測を行うことで圧力変動時
の計測を安定化することができる。
Further, by providing the fluctuation detecting means for detecting the vicinity of the zero of the AC component of the pressure fluctuation waveform, the range of the time for performing the flow measurement by detecting the fluctuation near the zero component of the pressure fluctuation is from the vicinity of the fluctuation near zero. Measurement can be started,
By performing the flow rate measurement within a time period in which the fluctuation is small, the measurement at the time of the pressure fluctuation can be stabilized.

【0054】また、変動検出手段の出力信号の変動をカ
ウントする複数ビットのカウント手段と、前記カウント
手段のカウント値が、第1計時と第2計時で異なるように
して計測し、複数ビットのすべての組み合わせが同じ回
数だけ実現した時に流量を計測する流量検出手段を備え
ることで、すべての変動タイミングで計測することがで
きるので、平均化が行われ安定して流量を計測すること
ができる。
Also, a plurality of bits of counting means for counting the variation of the output signal of the variation detecting means, and counting is performed so that the count value of the counting means is different between the first timekeeping and the second timekeeping. By providing the flow rate detecting means for measuring the flow rate when the combination of the above is realized the same number of times, the measurement can be performed at all the fluctuation timings, so that the averaging is performed and the flow rate can be stably measured.

【0055】また、変動検出手段の信号の周期を検出す
る周期検出手段と、前記周期検出手段の検出した周期
が、所定の周期の時にのみ計測を開始する計測制御手段
を備えることで、所定周期の時のみに計測を開始するこ
とで、所定の変動時に計測が行え、安定した流量を計測
することができる。
Further, a cycle detecting means for detecting a cycle of a signal of the fluctuation detecting means, and a measuring control means for starting measurement only when the cycle detected by the cycle detecting means is a predetermined cycle is provided. By starting the measurement only at the time of, measurement can be performed at the time of a predetermined fluctuation, and a stable flow rate can be measured.

【0056】また、変動検出手段の信号が検出できなか
った時は、所定時間後に計測を自動的にスタートする検
出解除手段を備えることで、変動がなくなった場合でも
所定時間がくれば自動的に流量を計測することができ
る。
Further, when a signal from the fluctuation detecting means cannot be detected, a detection canceling means for automatically starting measurement after a predetermined time is provided. The flow rate can be measured.

【0057】また、第1振動手段および第2振動手段
は、圧電式振動子からなる構成とすることで、超音波を
送受信に用いながら、かつ圧電振動子で圧力変動も検出
することができる。
Further, since the first vibrating means and the second vibrating means are constituted by piezoelectric vibrators, it is possible to detect pressure fluctuations by using the piezoelectric vibrator while using ultrasonic waves for transmission and reception.

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

【図1】本発明の実施例1の流量計のブロック図FIG. 1 is a block diagram of a flow meter according to a first embodiment of the present invention.

【図2】同流量計の構成を示す断面図FIG. 2 is a sectional view showing a configuration of the flow meter.

【図3】同流量計の動作を示すタイミングチャートFIG. 3 is a timing chart showing the operation of the flow meter.

【図4】同流量計の動作を示す別のタイミングチャートFIG. 4 is another timing chart showing the operation of the flow meter.

【図5】同流量計の動作を示すフローチャートFIG. 5 is a flowchart showing the operation of the flow meter.

【図6】同流量計の動作を示す別のフローチャートFIG. 6 is another flowchart showing the operation of the flow meter.

【図7】同流量計を示すブロック図FIG. 7 is a block diagram showing the flow meter.

【図8】本発明の実施例2の流量計の動作を示すタイミ
ングチャート
FIG. 8 is a timing chart showing the operation of the flow meter according to the second embodiment of the present invention.

【図9】同流量計の動作を示すフローチャートFIG. 9 is a flowchart showing the operation of the flow meter.

【図10】本発明の実施例3の流量計の動作を示すタイ
ミングチャート
FIG. 10 is a timing chart showing the operation of the flow meter according to the third embodiment of the present invention.

【図11】同流量計の動作を示すフローチャートFIG. 11 is a flowchart showing the operation of the flow meter.

【図12】本発明の実施例4の流量計を示すブロック図FIG. 12 is a block diagram illustrating a flow meter according to a fourth embodiment of the present invention.

【図13】同流量計の動作を示すタイミングチャートFIG. 13 is a timing chart showing the operation of the flow meter.

【図14】本発明の実施例5の流量計を示すブロック図FIG. 14 is a block diagram showing a flow meter according to a fifth embodiment of the present invention.

【図15】同流量計の動作を示すフローチャートFIG. 15 is a flowchart showing the operation of the flow meter.

【図16】従来の流量計を示すブロック図FIG. 16 is a block diagram showing a conventional flow meter.

【図17】従来の別の流量計を示すブロック図FIG. 17 is a block diagram showing another conventional flow meter.

【符号の説明】[Explanation of symbols]

23 第1の圧電振動子(送受信手段、第1振動手段) 24 流路 25 第2の圧電振動子(送受信手段、第2振動手段) 26 切換手段 27 計時手段 28 流量検出手段 29 変動検出手段 30 計測制御手段 31 選択手段 34 繰返手段 35 動作チェック手段 36 カウント手段 37 周期検出手段 23 first piezoelectric vibrator (transmitting / receiving means, first vibrating means) 24 flow path 25 second piezoelectric vibrator (transmitting / receiving means, second vibrating means) 26 switching means 27 clocking means 28 flow detecting means 29 fluctuation detecting means 30 Measurement control means 31 selection means 34 repetition means 35 operation check means 36 counting means 37 cycle detection means

───────────────────────────────────────────────────── フロントページの続き (72)発明者 安倍 秀二 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 Fターム(参考) 2F031 AC03 AD10 2F035 DA14 DA16 DA19 GA02  ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shuji Abe 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 2F031 AC03 AD10 2F035 DA14 DA16 DA19 GA02

Claims (12)

【特許請求の範囲】[Claims] 【請求項1】流路に設けられ音波を送受信する送受信手
段と、前記送受信手段で送受信される音波の伝搬時間を
計測する計時手段と、前記計時手段の値に基づいて流量
を検出する流量検出手段と、前記送受信手段で流路内の
変動を計測する変動検出手段と、前記変動検出手段の変
動のタイミングに同期して計測を開始する計測制御手段
とを備えた流量計。
1. A transmitting / receiving means provided in a flow path for transmitting and receiving a sound wave, a time measuring means for measuring a propagation time of a sound wave transmitted and received by the transmitting / receiving means, and a flow rate detecting means for detecting a flow rate based on a value of the time measuring means. A flowmeter comprising: means, a fluctuation detecting means for measuring fluctuations in the flow path by the transmission / reception means, and a measurement control means for starting measurement in synchronization with the fluctuation timing of the fluctuation detecting means.
【請求項2】流路に設けられて音波を送受信する第1振
動手段および第2振動手段と、前記第1振動手段および
第2振動手段の送受信の動作を切換える切換手段と、前
記第1振動手段および第2振動手段の少なくとも一方で
流路内の圧力変動を検出する変動検出手段と、前記第1
振動手段および第2振動手段で送受信される音波の伝搬
時間を計測する計時手段と、前記変動検出手段の出力が
所定変化した時に流路の上流側の第1振動手段から下流
側の第2振動手段に伝搬する第1計時時間T1を前記計
時手段が測定し、また前記変動検出手段の出力が前記所
定変化と逆に変化した時には流路の下流側の第2振動手
段から上流側の第1振動手段に伝搬する第2計時時間T
2を前記計時手段が測定する制御を行う計測制御手段
と、前記第1計時時間T1と前記第2計時時間T2を用い
て流量を算出する流量検出手段とを備えた流量計。
2. A first vibration means and a second vibration means provided in a flow path for transmitting and receiving a sound wave, a switching means for switching transmission and reception operations of the first vibration means and the second vibration means, and the first vibration means A fluctuation detecting means for detecting a pressure fluctuation in the flow path in at least one of the first means and the second vibrating means;
A timer for measuring the propagation time of a sound wave transmitted and received by the vibration means and the second vibration means, and a second vibration downstream from the first vibration means on the upstream side of the flow path when the output of the fluctuation detecting means changes by a predetermined amount. The first time measuring time T1 propagating to the means is measured by the time measuring means, and when the output of the fluctuation detecting means changes in reverse to the predetermined change, the first vibrating means on the downstream side of the flow path from the first vibrating means on the upstream side Second time T that propagates to the vibration means
2. A flowmeter comprising: a measurement control means for controlling the measurement of the second time by the time measurement means; and a flow rate detection means for calculating a flow rate using the first time measurement time T1 and the second time measurement time T2.
【請求項3】変動検出手段の出力が所定変化した時に第
1計時時間T1の測定を開始し、前記変動検出手段の出
力が前記所定変化と逆に変化した時に第2計時時間T2
の測定を開始する計測制御と、次回の計測時は、変動検
出手段の出力が前記所定変化と逆に変化した時に第1計
時時間T1の測定を開始し、前記変動検出手段の出力が
所定変化した時に第2計時時間T2の測定を開始計測制
御を行う計測制御手段と、計測開始を交互に変更しなが
ら前回の第1計時時間T1と第2計時時間T2を用いて求
めた第1流量と、次回の第1計時時間T1と第2計時時間
T2を用いて求めた第2流量を逐次平均処理することに
より流量を算出する流量検出手段を備えた請求項2記載
の流量計。
3. When the output of the fluctuation detecting means changes by a predetermined amount,
(1) The measurement of the time measurement time T1 is started, and when the output of the fluctuation detecting means changes in reverse to the predetermined change, the second time measurement time T2
And measurement control for starting the measurement of the first time, and at the next measurement, the measurement of the first timed time T1 is started when the output of the fluctuation detecting means changes in reverse to the predetermined change, and the output of the fluctuation detecting means The measurement of the second time T2 is started when the measurement is started. The measurement control means performs measurement control, and the first flow rate obtained by using the previous first time T1 and the second time T2 while changing the measurement start alternately. 3. The flowmeter according to claim 2, further comprising a flow rate detecting means for calculating a flow rate by sequentially averaging a second flow rate obtained using the next first time measurement time T1 and second time measurement time T2.
【請求項4】音波による送受信を複数回行う繰返手段を
備えた請求項1〜3のいずれか1項記載の流量計。
4. The flowmeter according to claim 1, further comprising a repetition means for performing transmission and reception by a sound wave a plurality of times.
【請求項5】変動周期の整数倍時間にわたって送受信を
複数回行う繰返手段を備えた請求項4記載の流量計。
5. The flow meter according to claim 4, further comprising a repetition means for performing transmission and reception a plurality of times over an integral multiple of the fluctuation period.
【請求項6】変動検出手段の出力が所定変化した時に音
波の送受信計測を開始し、前記変動検出手段の出力が前
記所定変化と同じ変化をするまで繰返し音波の送受信計
測を行う繰返手段を備えた請求項4記載の流量計。
6. A repetition means for starting transmission / reception measurement of a sound wave when the output of the fluctuation detection means changes by a predetermined amount, and repeatedly performing transmission / reception measurement of a sound wave until the output of the fluctuation detection means changes the same as the predetermined change. The flow meter according to claim 4, further comprising:
【請求項7】第1振動手段および第2振動手段を、音波
の送受信に用いる場合と、圧力変動の検出に用いる場合
を切換える選択手段を備えた請求項1〜6のいずれか1
項記載の流量計。
7. A method according to claim 1, further comprising a selecting means for switching between a case where the first vibrating means and the second vibrating means are used for transmitting and receiving a sound wave and a case where the first vibrating means is used for detecting a pressure fluctuation.
Flow meter according to the item.
【請求項8】圧力変動波形の交流成分のゼロ付近を検出
する変動検出手段を備えた請求項2〜7のいずれか1項
記載の流量計。
8. The flowmeter according to claim 2, further comprising a fluctuation detecting means for detecting a vicinity of zero of an AC component of the pressure fluctuation waveform.
【請求項9】変動検出手段の出力信号の変動をカウント
する複数ビットのカウント手段と、前記カウント手段の
カウント値が、第1計時と第2計時で異なるようにして計
測し、複数ビットのすべての組み合わせが同じ回数だけ
実現した時に流量を計測する流量検出手段を備えた請求
項1〜8のいずれか1項記載の流量計。
9. A multi-bit counting means for counting fluctuations of an output signal of a fluctuation detecting means, and measuring the count value of said counting means so as to be different between a first clock and a second clock. The flowmeter according to any one of claims 1 to 8, further comprising a flow rate detecting means for measuring a flow rate when the combination of the above is realized the same number of times.
【請求項10】変動検出手段の信号の周期を検出する周
期検出手段と、前記周期検出手段の検出した周期が、所
定の周期の時にのみ計測を開始する計測制御手段を備え
た請求項1〜8のいずれか1項記載の流量計。
10. A cycle detecting means for detecting a cycle of a signal from a fluctuation detecting means, and a measuring control means for starting measurement only when the cycle detected by the cycle detecting means is a predetermined cycle. 9. The flow meter according to any one of 8 above.
【請求項11】変動検出手段の信号が検出できなかった
時は、所定時間後に計測を自動的にスタートする検出解
除手段を備えた請求項1〜10のいずれか1項記載の流
量計。
11. The flowmeter according to claim 1, further comprising detection canceling means for automatically starting measurement after a predetermined time when a signal from the fluctuation detecting means cannot be detected.
【請求項12】送受信手段および第1振動手段と第2振
動手段は、圧電式振動子からなる請求項1〜11のいず
れか1項記載の流量計。
12. The flowmeter according to claim 1, wherein the transmitting / receiving means and the first and second vibrating means comprise a piezoelectric vibrator.
JP17795299A 1999-06-24 1999-06-24 Flowmeter Expired - Fee Related JP4556253B2 (en)

Priority Applications (15)

Application Number Priority Date Filing Date Title
JP17795299A JP4556253B2 (en) 1999-06-24 1999-06-24 Flowmeter
CNB00809439XA CN1293369C (en) 1999-06-24 2000-06-23 Flowmeter
CN2008100032863A CN101266159B (en) 1999-06-24 2000-06-23 Flowmeter
AU55693/00A AU5569300A (en) 1999-06-24 2000-06-23 Flowmeter
CNB2004100947648A CN100501345C (en) 1999-06-24 2000-06-23 Flowmeter
US10/019,418 US6796189B1 (en) 1999-06-24 2000-06-23 Ultrasonic flowmeter having sequentially changed driving method
PCT/JP2000/004165 WO2001001081A1 (en) 1999-06-24 2000-06-23 Flowmeter
KR10-2001-7016609A KR100487690B1 (en) 1999-06-24 2000-06-23 Flowmeter
CNB2006101684850A CN100545588C (en) 1999-06-24 2000-06-23 Flowmeter
CN2006101058560A CN1912552B (en) 1999-06-24 2000-06-23 Flowmeter
EP00940829A EP1243901A4 (en) 1999-06-24 2000-06-23 Flowmeter
CN2007101099584A CN101074885B (en) 1999-06-24 2000-06-23 Flowmeter
US10/711,053 US6915704B2 (en) 1999-06-24 2004-08-19 Ultrasonic flowmeter including stable flow rate calculation means based on instantaneous flow rate
US10/711,054 US6941821B2 (en) 1999-06-24 2004-08-19 Ultrasonic flowmeter including stable flow rate calculation means based on instantaneous flow rate
US10/711,055 US7082841B2 (en) 1999-06-24 2004-08-19 Ultrasonic flowmeter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17795299A JP4556253B2 (en) 1999-06-24 1999-06-24 Flowmeter

Publications (2)

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JP2001004419A true JP2001004419A (en) 2001-01-12
JP4556253B2 JP4556253B2 (en) 2010-10-06

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CN (5) CN100501345C (en)

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Publication number Publication date
CN1782676A (en) 2006-06-07
CN1912552A (en) 2007-02-14
CN101074885A (en) 2007-11-21
CN101074885B (en) 2010-06-16
CN101266159A (en) 2008-09-17
CN1912552B (en) 2011-05-11
CN100545588C (en) 2009-09-30
CN100501345C (en) 2009-06-17
CN1975349A (en) 2007-06-06
JP4556253B2 (en) 2010-10-06
CN101266159B (en) 2011-02-16

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