JP2002310764A - Flow-rate measuring device - Google Patents
Flow-rate measuring deviceInfo
- Publication number
- JP2002310764A JP2002310764A JP2001110950A JP2001110950A JP2002310764A JP 2002310764 A JP2002310764 A JP 2002310764A JP 2001110950 A JP2001110950 A JP 2001110950A JP 2001110950 A JP2001110950 A JP 2001110950A JP 2002310764 A JP2002310764 A JP 2002310764A
- Authority
- JP
- Japan
- Prior art keywords
- comparison
- cycle
- flow
- flow rate
- output
- 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
Links
Landscapes
- Measuring Volume Flow (AREA)
- Details Of Flowmeters (AREA)
Abstract
Description
【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 gas.
【０００２】[0002]
【従来の技術】従来のこの種の流量計測装置では、圧力
変動が発生した場合であっても正確な流量を求めるため
に様々な提案がなされており、例えば特開平１１−４４
５６３号公報に記載されているようなものがあった。図
４を用いてこの種の流量計測装置の動作について説明す
る。2. Description of the Related Art Various proposals have been made in this type of conventional flow rate measuring apparatus to obtain an accurate flow rate even when a pressure fluctuation occurs.
There was one such as described in JP-A-563. The operation of this type of flow measurement device will be described with reference to FIG.
【０００３】図４において、流体流路１に、流量検出手
段としての第１振動子２と第２振動子３が、流れの方向
に対向して取り付けられていて、流量計測手段１６がこ
れらふたつの振動子間で超音波の送受信を行い、その時
超音波伝搬に要した時間を用いて流量値を求めている。
このような構成においては、流路１の内部で圧力変動が
発生した場合にはその影響を受けて、流速が変化するた
め正確な流量値を求められない。そのため、圧力検出手
段１０が取り付けられており、圧力検出手段１０の出力
信号の交流成分が脈動計測手段１１に入力されるととも
に、比較手段１２で信号レベルのゼロクロス通過点が検
出され、これに同期して、流量計測手段の発停が制御さ
れている。この構成により、圧力周期に合わせて計測時
間を制御し、脈動時の正確な平均流量を求めることが可
能となっていた。In FIG. 4, a first vibrator 2 and a second vibrator 3 as flow rate detecting means are attached to a fluid flow path 1 so as to oppose each other in the flow direction. The ultrasonic wave is transmitted and received between the transducers, and the flow rate value is obtained using the time required for the ultrasonic wave propagation at that time.
In such a configuration, when a pressure fluctuation occurs inside the flow path 1, the flow rate changes due to the influence of the pressure fluctuation, so that an accurate flow value cannot be obtained. Therefore, the pressure detecting means 10 is attached, the AC component of the output signal of the pressure detecting means 10 is input to the pulsation measuring means 11, and the zero-crossing point of the signal level is detected by the comparing means 12 and synchronized therewith. Thus, the start / stop of the flow rate measuring means is controlled. With this configuration, it has been possible to control the measurement time in accordance with the pressure cycle and to obtain an accurate average flow rate during pulsation.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら上記従来
の流量計測装置では、次のような課題があった。すなわ
ち、圧力信号波形は必ずしも、正弦波の様に単純な波形
ではなく、多くの場合は複数の周波数成分が合成された
複雑な波形となっている。また、比較的正弦波に近い波
形であっても、１周期毎の波形を取ると周期やレベルに
多少のばらつきを含んでいる場合もある。そのため、ゼ
ロクロスと同期して計測しても、必ずしも、圧力変動周
期の流量を平均化したことにならないため、正確な平均
流量が求められず、計測精度の点で課題を有していた。However, the above conventional flow rate measuring device has the following problems. That is, the pressure signal waveform is not necessarily a simple waveform like a sine wave, but is often a complex waveform in which a plurality of frequency components are synthesized. In addition, even if the waveform is relatively close to a sine wave, if the waveform is taken every cycle, the cycle and level may include some variation. Therefore, even if the measurement is performed in synchronization with the zero cross, the flow rate in the pressure fluctuation cycle is not necessarily averaged, so that an accurate average flow rate cannot be obtained, and there is a problem in measurement accuracy.
【０００５】本発明は、前記従来の課題を解決するもの
で、圧力変動周期を正確に捉えることにより、流量計測
のタイミングを最適化し、高精度の計測が可能な流量計
測装置を提供することを目的とする。An object of the present invention is to solve the above-mentioned conventional problems and to provide a flow rate measuring apparatus capable of optimizing a timing of a flow rate measurement and accurately measuring a pressure fluctuation cycle by accurately grasping a pressure fluctuation period. Aim.
【０００６】[0006]
【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、流体の流量を検出
する流量検出手段と、流体の圧力変動を検出する脈動検
出手段と、前記脈動検出手段の出力と設定可能な比較基
準値とを比較する比較手段と、前記比較手段の出力より
脈動周期を計測する周期検出手段と、前記比較手段の比
較基準値を変更する設定変更手段と、前記周期計測手段
で求めた周期に応じて前記流量検出手段の動作時間を制
御する計測制御手段とを備えたものである。In order to solve the above-mentioned conventional problems, a flow rate measuring device according to the present invention comprises: a flow rate detecting means for detecting a flow rate of a fluid; a pulsation detecting means for detecting a pressure fluctuation of the fluid; Comparison means for comparing the output of the pulsation detection means with a settable comparison reference value; cycle detection means for measuring a pulsation cycle from the output of the comparison means; and setting change means for changing the comparison reference value of the comparison means And measurement control means for controlling the operation time of the flow rate detection means in accordance with the cycle obtained by the cycle measurement means.
【０００７】これによって、比較基準値を適切に定める
ことにより、正確な圧力変動周期を捉えて、流量計測の
タイミングを最適化できるので、圧力変動の影響を受け
ない高精度の流量計測を実現するものである。[0007] Thus, by appropriately determining the comparison reference value, an accurate pressure fluctuation period can be grasped, and the timing of the flow measurement can be optimized. Therefore, a highly accurate flow measurement which is not affected by the pressure fluctuation can be realized. Things.
【０００８】[0008]
【発明の実施の形態】請求項１に記載の発明は、流体の
流量を検出する流量検出手段と、流体の圧力変動を検出
する脈動検出手段と、前記脈動検出手段の出力と設定可
能な比較基準値とを比較する比較手段と、前記比較手段
の出力より脈動周期を計測する周期検出手段と、前記比
較手段の比較基準値を変更する設定変更手段と、前記周
期計測手段で求めた周期に応じて前記流量検出手段の動
作時間を制御する計測制御手段とを備えたことにより、
比較基準値を適切に定めることにより、正確な圧力変動
周期を捉えて、流量計測のタイミングを最適化できるの
で、圧力変動の影響を受けない高精度の流量計測を実現
できる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a flow rate detecting means for detecting a flow rate of a fluid, a pulsation detecting means for detecting a pressure fluctuation of the fluid, and a comparison which can be set with the output of the pulsation detecting means. Comparison means for comparing with a reference value, cycle detection means for measuring a pulsation cycle from the output of the comparison means, setting change means for changing the comparison reference value of the comparison means, and a cycle obtained by the cycle measurement means. Measurement control means for controlling the operation time of the flow rate detection means accordingly,
By appropriately determining the comparison reference value, an accurate pressure fluctuation cycle can be grasped and the timing of the flow rate measurement can be optimized, so that a highly accurate flow rate measurement not affected by the pressure fluctuation can be realized.
【０００９】請求項２に記載の発明は、特に、請求項１
に記載の設定変更手段を、周期検出手段の出力平均値が
小となるに従って比較手段の比較基準値を大とする構成
にすることにより、平均周期が短くて変化勾配の急な波
形であっても、圧力変動の緩やかな点を捉えて周期を検
出できるので、検出周期のばらつきを低減できる。The invention described in claim 2 is particularly advantageous in claim 1.
The setting change means described in (1) is configured to increase the comparison reference value of the comparison means as the output average value of the cycle detection means becomes smaller, so that the average cycle is short and the waveform has a steep change gradient. Also, since the cycle can be detected by capturing a point where the pressure fluctuation is gentle, variation in the detection cycle can be reduced.
【００１０】請求項３に記載の発明は、特に、請求項１
記載の設定変更手段を、周期検出手段の出力が所定値よ
り小さければ比較手段の比較基準値を大とする構成とす
ることにより、短時間で発生した変動を受け付けないの
で、ノイズや圧力波計の中割れの影響を回避して正確な
変動周期を求めることができる。[0010] The invention described in claim 3 is particularly advantageous in claim 1.
The setting change means described above is configured to increase the comparison reference value of the comparison means when the output of the cycle detection means is smaller than a predetermined value, so that fluctuations occurring in a short time are not accepted. Thus, an accurate fluctuation period can be obtained by avoiding the influence of medium cracking.
【００１１】請求項４に記載の発明は、特に、請求項１
記載の設定変更手段を、周期検出手段の出力ばらつきが
大きければ比較手段の比較基準値を大とする構成とする
ことにより、１周期毎のばらつきが大きな波形に対して
も、比較基準値を最適化できるので、正確な圧力周期を
求めることができる。[0011] The invention described in claim 4 is particularly advantageous in claim 1.
The setting change means described above is configured to increase the comparison reference value of the comparison means if the output variation of the cycle detection means is large, so that the comparison reference value is optimized even for a waveform having a large variation in each cycle. Therefore, an accurate pressure cycle can be obtained.
【００１２】請求項５に記載の発明は、特に、請求項１
から４いずれか１項記載の設定変更手段を、比較手段の
出力変化が所定時間以上なければ比較手段の比較基準値
を小とする構成とすることにより、比較基準値を過大に
上昇させることがなくなるため、比較基準値の最適化を
図ることができる。[0012] The invention described in claim 5 is particularly advantageous in claim 1.
In the configuration changing means according to any one of the above items 4, the comparison reference value of the comparison means is set to be small if the output change of the comparison means does not exceed a predetermined time, whereby the comparison reference value can be excessively increased. Therefore, the comparison reference value can be optimized.
【００１３】請求項６に記載の発明は、特に、請求項１
から５いずれか１項記載の計測制御手段の開始停止信号
を比較手段の出力変化点と同期して出力される構成とす
ることにより、圧力変動に対する時間遅れの小さい計測
ができるため、圧力変動に対する追従性を高めることが
できる。[0013] The invention described in claim 6 is particularly advantageous in claim 1.
5. The configuration in which the start / stop signal of the measurement control means according to any one of (5) to (5) is output in synchronization with the output change point of the comparison means, so that measurement with a small time delay to pressure fluctuation can be performed. Followability can be improved.
【００１４】請求項７に記載の発明は、特に、請求項１
から５いずれか１項記載の計測制御手段を周期検出手段
の出力変化点とは非同期で出力される構成とすることに
より、流量計測中の不要信号の影響を回避できるため、
ノイズの影響を受け難い信頼性の高い計測が可能とな
る。[0014] The invention described in claim 7 is particularly advantageous in claim 1.
By setting the measurement control means according to any one of (5) to (5) to be output asynchronously with the output change point of the cycle detection means, the influence of unnecessary signals during flow rate measurement can be avoided.
Highly reliable measurement that is not easily affected by noise can be performed.
【００１５】[0015]
【実施例】以下、本発明の実施例について図面を用いて
説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１６】（実施例１）図１は本発明の実施例１の流
量計測装置を示すブロック図である。図１において、流
体流路１の途中に流量検出手段として超音波を発信する
第１振動子２と受信する第２振動子３が流れ方向に配置
されている。４は第１振動子２への送信回路、５は第２
振動子３で受信した超音波を信号処理する受信回路で、
６は第１振動子２と第２振動子３の送受信を切換える切
換手段、７は受信回路５で超音波を検知した後第１振動
子２からの送信と第２振動子３での受信を複数回繰り返
す繰り返し手段、８は繰り返し手段７により行われる複
数回の超音波伝搬の所要時間を計測する計時手段、９は
計時測手段８の計測値から流量を求める流量演算手段で
ある。また、１０は流路１内の圧力を検出する圧力検出
手段、１１は圧力検出手段１１の信号出力の交流成分を
コンデンサを介して取り出す脈動検出手段、１２は脈動
検出手段により取り出された交流信号と設定電圧とを比
較し、その大小関係を二値信号に変換して出力する比較
手段、１３は比較手段１２の二値信号の小から大への出
力変化点の間隔を計測し脈動周期を検出する周期検出手
段、１４は周波数検出手段１３の出力結果に応じて流量
計測時間を制御する計測制御手段、１５は比較手段１２
の比較基準値を変更する設定変更手段である。(Embodiment 1) FIG. 1 is a block diagram showing a flow rate measuring apparatus according to Embodiment 1 of the present invention. In FIG. 1, a first vibrator 2 for transmitting an ultrasonic wave and a second vibrator 3 for receiving an ultrasonic wave are arranged in the flow direction in the fluid flow path 1 as flow rate detecting means. 4 is a transmitting circuit to the first vibrator 2 and 5 is a second transmitting circuit.
A receiving circuit for processing the ultrasonic waves received by the transducer 3;
6 is a switching means for switching between transmission and reception of the first vibrator 2 and the second vibrator 3, and 7 is a transmission circuit for detecting transmission of ultrasonic waves from the first transducer 2 and reception of the second transducer 3 after detecting the ultrasonic waves. A repetition means for repeating a plurality of times, a time counting means for measuring a time required for a plurality of times of ultrasonic wave propagation performed by the repetition means, and a flow calculation means for obtaining a flow rate from a measured value of the time measurement means. 10 is a pressure detecting means for detecting the pressure in the flow path 1, 11 is a pulsation detecting means for extracting an AC component of the signal output of the pressure detecting means 11 through a capacitor, and 12 is an AC signal extracted by the pulsation detecting means. And a set voltage, and compares the magnitude relationship into a binary signal and outputs the binary signal. The comparator 13 measures the interval between the output change points of the binary signal from small to large, and determines the pulsation cycle. A period detecting means for detecting; a measuring control means for controlling a flow rate measuring time in accordance with an output result of the frequency detecting means;
Is a setting changing means for changing the comparison reference value of the above.
【００１７】次に、動作作用について説明する。静止流
体中の音速をｃ、流体の流れの速さをｖとすると、流れ
の順方向の超音波の伝搬速度は（ｃ＋ｖ）、逆方向の伝
搬速度は（ｃ−ｖ）となる。振動子２と３の間の距離を
Ｌ、超音波伝搬軸と流路の中心軸とがなす角度をθ、流
れの順方向に発信された超音波の伝搬する時間をｔ1、
流れの逆方向に発信された超音波の伝搬する時間をｔ2
とすると、 ｔ1＝Ｌ／（ｃ＋ｖｃｏｓθ） （１） ｔ2＝Ｌ／（ｃ−ｖｃｏｓθ） （２） となる。（１）式、（２）式より流速ｖを求めると、 ｖ＝（Ｌ／２ｃｏｓθ）・（１／ｔ1−１／ｔ2） （３） となり、Ｌとθが既知ならｔ1、ｔ2を計測して流速ｖが
求められる。ここで、流路断面積をＳ、補正係数をＫと
すれば、流量Ｑは Ｑ＝Ｋ・Ｓ・ｖ （４） となる。式（３）、（４）から明らかなように、伝搬時
間を求めることにより流量Ｑが求められる。一方、流路
１内部に圧力変動が発生している場合には流速ｖは一定
しないが、周期的な変動が発生している場合には、圧力
変動ｎ周期の間の伝搬時間を計測し、その平均値を求め
れば、変動の影響はキャンセルされて、正確な値を求め
ることができる。Next, the operation and operation will be described. Assuming that the speed of sound in the stationary fluid is c and the speed of the flow of the fluid is v, the propagation speed of the ultrasonic wave in the forward direction of the flow is (c + v) and the propagation speed in the reverse direction is (cv). The distance between the transducers 2 and 3 is L, the angle between the ultrasonic wave propagation axis and the center axis of the flow path is θ, the propagation time of the ultrasonic wave transmitted in the forward direction of the flow is t 1 ,
The propagation time of the ultrasonic wave transmitted in the opposite direction of the flow is t 2
Then, t 1 = L / (c + vcos θ) (1) t 2 = L / (c−vcos θ) (2) When the flow velocity v is obtained from the equations (1) and (2), v = (L / 2 cos θ) · (1 / t 1 −1 / t 2 ) (3), and if L and θ are known, t 1 and t 2 is measured to determine the flow velocity v. Here, assuming that the flow path cross-sectional area is S and the correction coefficient is K, the flow rate Q is as follows: Q = KSV (4) As is clear from equations (3) and (4), the flow rate Q is obtained by obtaining the propagation time. On the other hand, the flow velocity v is not constant when the pressure fluctuation occurs inside the flow path 1, but when the periodic fluctuation occurs, the propagation time during the pressure fluctuation n cycle is measured, If the average value is obtained, the influence of the fluctuation is canceled, and an accurate value can be obtained.
【００１８】次に図２を用いて、計測制御手順について
説明する。脈動検出手段１１の出力信号と比較基準値０
Ｖとの比較処理が比較手段１２で行われる。比較手段１
２は脈動検出手段１１の交流信号が比較基準値より高け
ればＨ、低ければＬの二値信号を出力する。計測制御手
段１４は、比較手段１２の立ち上がり波形、すなわち、
出力信号がＬからＨに変化する変化点ｔ1aと同期して、
繰り返し手段７に対して、繰り返し計測の開始信号を出
力する。この時、切換手段６は、予め第１振動子２を送
信回路４に、第２振動子３を受信回路５に接続して超音
波を流れの順方向に送信した伝搬時間を計測する体制が
取られている。計測制御手段１４の開始信号出力を受け
て送受信が開始され、送受信１回が終了する毎に、繰り
返し手段７は送受信の回数をカウントすると共に、送信
回路４に超音波の送信を指示する。繰り返し手段７での
繰り返し計測と平行して、計時手段８では送受信に要し
た時間が計測される。そして、計測制御手段１４は、再
び比較手段１２の出力がＬからＨに変化する点ｔ1bで、
計測の停止信号を出力する。計測制御手段１４からの停
止信号を受けると、繰り返し手段７は、新たな送受信を
中止する。ここで、計時手段８で計測した伝搬時間と繰
り返し手段７行った送受信の繰り返し回数を元に、流量
演算手段９で流れの順方向の伝搬時間ｔ１を求める。こ
の後、切換手段６は第１振動子２を受信回路５を第２振
動子３に繋ぎ換えることにより流れの逆方向に超音波を
送信した伝搬時間を計測する体制を取る。比較手段１２
の信号がＬからＨに切換わる点ｔ2aおよびｔ2bで、計測
制御手段１４がそれぞれ開始信号、停止信号を出力し、
順方向と同様の手順で、逆方向の計測が行われる。以上
のように求めた順方向、逆方向の伝搬時間を基に、流量
演算手段９では（３）、（４）式を用いて流量Ｑを求め
る。Next, the measurement control procedure will be described with reference to FIG. The output signal of the pulsation detecting means 11 and the comparison reference value 0
Comparison processing with V is performed by the comparison means 12. Comparison means 1
2 outputs a binary signal of H if the AC signal of the pulsation detecting means 11 is higher than the comparison reference value, and outputs an L signal if it is lower than the comparison reference value. The measurement control unit 14 calculates the rising waveform of the comparison unit 12,
In synchronization with a transition point t 1a at which the output signal changes from L to H,
A repetition measurement start signal is output to the repetition means 7. At this time, the switching means 6 has a system in which the first transducer 2 is connected to the transmission circuit 4 and the second transducer 3 is connected to the reception circuit 5 to measure the propagation time of transmitting the ultrasonic wave in the forward direction. Has been taken. The transmission / reception is started in response to the start signal output of the measurement control unit 14, and each time one transmission / reception is completed, the repetition unit 7 counts the number of transmission / reception and instructs the transmission circuit 4 to transmit an ultrasonic wave. In parallel with the repetitive measurement by the repetition means 7, the time measurement means 8 measures the time required for transmission and reception. Then, the measurement control unit 14 returns to the point t 1b at which the output of the comparison unit 12 changes from L to H again,
Outputs measurement stop signal. Upon receiving the stop signal from the measurement control means 14, the repetition means 7 stops new transmission and reception. Here, based on the propagation time measured by the timer 8 and the number of repetitions of transmission / reception performed by the repetition unit 7, the flow calculation unit 9 obtains the propagation time t1 in the forward direction of the flow. Thereafter, the switching means 6 takes a system of measuring the propagation time of transmitting the ultrasonic wave in the reverse direction of the flow by connecting the first vibrator 2 to the receiving circuit 5 and the second vibrator 3. Comparison means 12
At points t 2a and t 2b at which the signal of L changes from L to H, the measurement control means 14 outputs a start signal and a stop signal, respectively.
The measurement in the reverse direction is performed in the same procedure as in the forward direction. Based on the forward and backward propagation times determined as described above, the flow rate calculating means 9 calculates the flow rate Q using the equations (3) and (4).
【００１９】ここでは、比較手段１２における比較基準
値は０Ｖとしたが、この値は固定されるものではない。
設定変更手段１５により脈動波形の発生原因、周期、絶
対レベルに応じて適正な値に設定することにより、周期
検出の精度が向上し、結果として流量計測の精度が向上
する。Here, the comparison reference value in the comparison means 12 is 0 V, but this value is not fixed.
By setting appropriate values in accordance with the cause, period, and absolute level of the pulsation waveform by the setting change unit 15, the accuracy of period detection is improved, and as a result, the accuracy of flow measurement is improved.
【００２０】以上のように、本実施例において、設定変
更手段が比較基準値を適切に定めることにより、正確な
圧力変動周期を捉えて、流量計測のタイミングを最適化
できるので、圧力変動の影響を受けない高精度の流量計
測を実現できる。As described above, in the present embodiment, by setting the comparison reference value appropriately by the setting changing means, an accurate pressure fluctuation period can be grasped, and the timing of the flow rate measurement can be optimized. High-precision flow measurement that is not affected by noise can be realized.
【００２１】特に、周期検出手段１３の平均周期が小と
なるに従って、比較手段１２の比較基準値を大とするこ
とにより、平均周期が短くて変化勾配の急な波形であっ
ても、圧力変動の緩やかな点を捉えて周期を検出できる
ので、検出周期のばらつきを低減できる。In particular, by increasing the comparison reference value of the comparison means 12 as the average cycle of the cycle detection means 13 becomes small, even if the average cycle is short and the waveform has a steep change gradient, the pressure fluctuation can be reduced. Since the period can be detected by grasping the gentle points of the above, variations in the detection period can be reduced.
【００２２】（実施例２）図３は、本発明の実施例２の
動作を説明するタイミングチャートである。脈動波形が
図２で示したような正弦波であれば、１周期でゼロクロ
スを２回生じるが、図３で示すような波形であったとす
ると、１周期の間に４回ゼロクロスを生じる。以後、こ
のような現象を中割れ現象と称する。比較手段１２の比
較基準値の初期値を０とすると、比較手段１２の出力は
図の如く変化し、周期検出手段１３の検出値がＴa、Ｔb
と交互に変化する。この場合、Ｔaの期間では、圧力平
均値はプラス側、Ｔbの期間ではマイナス側に振れるた
め、いずれの期間で平均化したとしても流量平均値の真
値を得ることはできない。設定変更手段１５は、周期検
出手段１５で周期を求める毎に予め定めた所定値Ｔ
s（Ｔb＞Ｔs＞Ｔa）と比較処理を行い、Ｔsより小さな
値を検出すると、中割れ波形と判断して比較手段１２の
比較基準値をＶ1に変更する。これにより、比較手段１
２の出力は図３後半のように変化し、常に一定周期Ｔc
が得られるになる。その結果、脈動の影響がキャンセル
されて正確な流量値を求めることができるようになる。(Embodiment 2) FIG. 3 is a timing chart for explaining the operation of Embodiment 2 of the present invention. If the pulsation waveform is a sine wave as shown in FIG. 2, zero cross occurs twice in one cycle, but if the waveform is as shown in FIG. 3, zero cross occurs four times in one cycle. Hereinafter, such a phenomenon is referred to as a medium cracking phenomenon. Assuming that the initial value of the comparison reference value of the comparison means 12 is 0, the output of the comparison means 12 changes as shown in the figure, and the detection values of the cycle detection means 13 are Ta , Tb.
And alternately. In this case, in the period T a, the pressure average is positive, since the swing in the negative side in a period of T b, it is impossible to obtain the true value of the flow rate average value even when averaged over any given period. The setting change means 15 has a predetermined value T each time the cycle is obtained by the cycle detection means 15.
s (T b> T s> T a) and performs a comparison process, to change when detecting the value smaller than T s, the comparison reference value of the comparison means 12 determines that the medium cracking waveform V 1. Thereby, the comparison means 1
The output of the 2 changes as the second half 3 is always constant period T c
Will be obtained. As a result, the influence of the pulsation is canceled and an accurate flow value can be obtained.
【００２３】以上のように、本実施例においては、周期
検出手段の計測周期が所定値より小さければ比較手段の
比較基準値を大とすることで、短時間で発生した変動を
受け付けないので、ノイズや圧力波計の中割れの影響を
回避して正確な変動周期を求めることができる。As described above, in the present embodiment, if the measurement cycle of the cycle detection means is smaller than the predetermined value, the comparison reference value of the comparison means is set to be large, so that the fluctuation generated in a short time is not accepted. An accurate fluctuation cycle can be obtained by avoiding the influence of noise and cracks in the pressure wave meter.
【００２４】また、別の方法として、判定手段１６で、
周期のばらつきを基に比較手段１２の比較基準値を変更
しても良い。この場合には、圧力周期はほぼ一定であっ
ても、波形周期のばらつきが大きくなるような場合にも
対応して、比較基準値を最適化できるので、正確な圧力
周期を求めることができる。ばらつきを求める方法は一
定期間内の標準偏差を求める方法であっても、最大値と
最小値の差を求める方法であっても良い。As another method, the determination means 16
The comparison reference value of the comparison means 12 may be changed based on the variation of the period. In this case, even when the pressure cycle is substantially constant, the comparison reference value can be optimized in response to a case where the variation of the waveform cycle becomes large, so that an accurate pressure cycle can be obtained. The method of obtaining the variation may be a method of obtaining a standard deviation within a certain period, or a method of obtaining a difference between a maximum value and a minimum value.
【００２５】更に、本実施例においては、比較基準値の
変更度合いが大きすぎると、比較手段１２の出力がＬの
まま変化しなくなる場合も考えられる。この場合、判定
手段１６が所定時間以上、比較手段１２の立ち上がり信
号を検出できない場合に、比較基準値を小さく変化させ
れば良い。これによって、比較基準値を過大に上昇させ
ることがなくなるため、比較基準値の最適化を図ること
ができる。Further, in this embodiment, if the degree of change of the comparison reference value is too large, the output of the comparison means 12 may remain unchanged at L and may not change. In this case, when the determination unit 16 cannot detect the rising signal of the comparison unit 12 for a predetermined time or more, the comparison reference value may be changed slightly. As a result, the comparison reference value is not excessively increased, so that the comparison reference value can be optimized.
【００２６】なお、各実施例において、比較手段１２の
出力の立ち上がりと同期する構成で説明したが、立ち下
がり信号であっても同様の効果が得られる。立ち上がり
立ち下がりいずれの場合であっても、比較手段１２の出
力変化と同期して流量計測を行うことにより、圧力変動
に対する時間遅れの小さい計測ができるため、圧力変動
に対する追従性を高めることができる。In each of the embodiments, a configuration synchronized with the rising edge of the output of the comparing means 12 has been described. However, the same effect can be obtained with a falling edge signal. In any case of rising and falling, by measuring the flow rate in synchronization with the output change of the comparing means 12, measurement with a small time lag with respect to the pressure fluctuation can be performed, so that the followability to the pressure fluctuation can be improved. .
【００２７】また、別の方法として、周期検出手段１３
で求めた時間を繰り返し手段１３の繰り返し回数に変換
する演算処理を施して、比較信号と非同期で計測する方
法もある。この場合には流量計測手段の動作が、脈動検
出手段や比較手段のノイズで妨げられる危険性がないの
で、流量計測中の不要信号の影響を回避できるため、ノ
イズの影響を受け難い信頼性の高い計測が可能となる。As another method, the period detecting means 13
There is also a method of performing an arithmetic process of converting the time obtained in the above into the number of repetitions of the repetition means 13 and measuring the time asynchronously with the comparison signal. In this case, there is no danger that the operation of the flow rate measuring means will be hindered by the noise of the pulsation detecting means and the comparing means. Therefore, it is possible to avoid the influence of unnecessary signals during the flow rate measurement. High measurement is possible.
【００２８】更に、各実施例は超音波振動子を用いたも
のについて説明したが、それ以外の例えば熱線式のフロ
ーセンサであっても同等の効果が得られる。また、気体
流量の計測装置に限らず、液体流量の計測装置であって
も同等の効果が得られることは言うまでもない。Further, in each of the embodiments, the description has been given of the one using the ultrasonic vibrator. However, the same effect can be obtained even by using a flow sensor of a hot wire type other than that. Further, it goes without saying that the same effect can be obtained not only with the gas flow rate measuring device but also with the liquid flow rate measuring device.
【００２９】[0029]
【発明の効果】以上説明したように本発明の請求項１〜
７に記載の発明によれば、比較基準値を適切に定めるこ
とにより正確な変動周期を捉えることが可能となり、圧
力変動の影響を受けない高精度の流量計測が可能とな
る。According to the present invention, as described above,
According to the invention described in Item 7, it is possible to capture an accurate fluctuation cycle by appropriately determining the comparison reference value, and it is possible to measure the flow rate with high accuracy without being affected by the pressure fluctuation.
【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 measurement device according to a first embodiment of the present invention.
【図２】同装置の動作を説明するタイミングチャートFIG. 2 is a timing chart illustrating the operation of the apparatus.
【図３】本発明の実施例２における流量計測装置の動作
を説明するタイミングチャートFIG. 3 is a timing chart illustrating an operation of the flow rate measuring device according to the second embodiment of the present invention.
【図４】従来の流量計測装置のブロック図FIG. 4 is a block diagram of a conventional flow measuring device.
２ 第１振動子（流量検出手段） ３ 第２振動子（流量検出手段） １１ 脈動検出手段 １２ 比較手段 １３ 周期検出手段 １４ 計測制御手段 １５ 設定変更手段 2 first vibrator (flow rate detecting means) 3 second vibrator (flow rate detecting means) 11 pulsation detecting means 12 comparing means 13 cycle detecting means 14 measurement controlling means 15 setting changing means
───────────────────────────────────────────────────── フロントページの続き (72)発明者 長岡 行夫 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） 2F030 CB09 CD13 CD17 CE04 CE05 2F031 AA03 AC03 2F035 GA02 GA03 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yukio Nagaoka 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 2F030 CB09 CD13 CD17 CE04 CE05 2F031 AA03 AC03 2F035 GA02 GA03
Claims (7)
流体の圧力変動を検出する脈動検出手段と、前記脈動検
出手段の出力と設定可能な比較基準値とを比較する比較
手段と、前記比較手段の出力より脈動周期を計測する周
期検出手段と、前記比較手段の比較基準値を変更する設
定変更手段と、前記周期計測手段で求めた周期に応じて
前記流量検出手段の動作時間を制御する計測制御手段と
を備えた流量計測装置。1. A flow rate detecting means for detecting a flow rate of a fluid,
Pulsation detection means for detecting pressure fluctuation of the fluid, comparison means for comparing the output of the pulsation detection means with a settable reference value, cycle detection means for measuring a pulsation cycle from the output of the comparison means, A flow rate measuring device comprising: a setting changing means for changing a comparison reference value of a comparing means; and a measurement control means for controlling an operation time of the flow rate detecting means according to a cycle obtained by the cycle measuring means.
均値が小となるに従って比較手段の比較基準値を大とす
る請求項１に記載の流量計測装置。2. The flow measuring device according to claim 1, wherein the setting change means increases the comparison reference value of the comparison means as the output average value of the cycle detection means decreases.
所定値より小さければ比較手段の比較基準値を大とする
請求項１に記載の流量計測装置。3. The flow measuring device according to claim 1, wherein the setting change means increases the comparison reference value of the comparison means when the output of the cycle detection means is smaller than a predetermined value.
らつきが大きければ比較手段の比較基準値を大とする請
求項１に記載の流量計測装置。4. The flow rate measuring device according to claim 1, wherein the setting changing means increases the comparison reference value of the comparing means when the output variation of the cycle detecting means is large.
所定時間以上なければ比較手段の比較基準値を小とする
請求項１〜４のいずれか１項に記載の流量計測装置。5. The flow rate measuring device according to claim 1, wherein the setting change unit decreases the comparison reference value of the comparison unit unless the output change of the comparison unit exceeds a predetermined time.
段の出力変化点と同期して出力される請求項１〜５のい
ずれか１項に記載の流量計測装置。6. The flow measuring device according to claim 1, wherein the start / stop signal of the measurement control means is output in synchronization with an output change point of the comparison means.
化点とは非同期で出力される請求項１〜５のいずれか１
項に記載の流量計測装置。7. The measurement control means according to claim 1, wherein the measurement control means outputs the data asynchronously with an output change point of the cycle detection means.
The flow measurement device according to the item.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001110950A JP4759829B2 (en) | 2001-04-10 | 2001-04-10 | Flow measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001110950A JP4759829B2 (en) | 2001-04-10 | 2001-04-10 | Flow measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002310764A true JP2002310764A (en) | 2002-10-23 |
| JP4759829B2 JP4759829B2 (en) | 2011-08-31 |
Family
ID=18962637
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001110950A Expired - Fee Related JP4759829B2 (en) | 2001-04-10 | 2001-04-10 | Flow measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4759829B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1144563A (en) * | 1997-07-29 | 1999-02-16 | Matsushita Electric Ind Co Ltd | Apparatus for measuring flow rate |
| JP2001255185A (en) * | 2000-03-09 | 2001-09-21 | Matsushita Electric Ind Co Ltd | Flow rate measuring system |
-
2001
- 2001-04-10 JP JP2001110950A patent/JP4759829B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1144563A (en) * | 1997-07-29 | 1999-02-16 | Matsushita Electric Ind Co Ltd | Apparatus for measuring flow rate |
| JP2001255185A (en) * | 2000-03-09 | 2001-09-21 | Matsushita Electric Ind Co Ltd | Flow rate measuring system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4759829B2 (en) | 2011-08-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4480485A (en) | Acoustic flowmeter with envelope midpoint tracking | |
| US5035147A (en) | Method and system for digital measurement of acoustic burst travel time in a fluid medium | |
| WO2011040027A1 (en) | Flow rate measuring device | |
| JPH11287817A (en) | Apparatus and method for measuring velocity | |
| JP2001004419A (en) | Flowmeter | |
| JP2007187506A (en) | Ultrasonic flowmeter | |
| JP2016099116A (en) | Ultrasonic flowmeter | |
| JPH047451B2 (en) | ||
| JP4835068B2 (en) | Fluid flow measuring device | |
| JP3350501B2 (en) | Flow measurement device | |
| JP2006308439A (en) | Flow measuring device of fluid | |
| JP2002310764A (en) | Flow-rate measuring device | |
| JP4759835B2 (en) | Flow measuring device | |
| JP2008185441A (en) | Ultrasonic flowmeter | |
| JP2001317975A (en) | Method and apparatus for ultrasonic flow velocity measurement | |
| JP2002296085A (en) | Ultrasonic flowmeter | |
| JP2008014800A (en) | Flow measuring instrument | |
| JPH0968569A (en) | Ultrasonic sensor | |
| JP5135807B2 (en) | Fluid flow measuring device | |
| JP5135806B2 (en) | Fluid flow measuring device | |
| JPH1019619A (en) | Method of ultrasonic measuring flow velocity | |
| JP6568289B2 (en) | Ultrasonic flow meter | |
| JPH01100414A (en) | Ultrasonic-wave flow velocity measuring apparatus | |
| JP4671481B2 (en) | Ultrasonic flow meter | |
| JP4425414B2 (en) | Flow measuring device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20080318 |
|
| RD01 | Notification of change of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7421 Effective date: 20080414 |
|
| RD01 | Notification of change of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7421 Effective date: 20091119 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20110222 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110301 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110419 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110510 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110523 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140617 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140617 Year of fee payment: 3 |
|
| LAPS | Cancellation because of no payment of annual fees |