JPH11281426A - Flow meter and method for measuring flow rate - Google Patents
Flow meter and method for measuring flow rateInfo
- Publication number
- JPH11281426A JPH11281426A JP8422998A JP8422998A JPH11281426A JP H11281426 A JPH11281426 A JP H11281426A JP 8422998 A JP8422998 A JP 8422998A JP 8422998 A JP8422998 A JP 8422998A JP H11281426 A JPH11281426 A JP H11281426A
- Authority
- JP
- Japan
- Prior art keywords
- flow rate
- flow
- pressure
- meter
- measuring
- 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
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は電子式ガスメータ等
に使用される流量を計測する流量計および流量計測方法
に係り、特に、流路中の流速を間欠的に計測して積算流
量を推測する推量式流量計の脈動(圧力変動、流速変
動)の影響を軽減する流量計および流量計測方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter and a flow rate measuring method for measuring a flow rate used in an electronic gas meter and the like, and in particular, to estimate an integrated flow rate by intermittently measuring a flow rate in a flow path. The present invention relates to a flowmeter and a flow measurement method for reducing the influence of pulsation (pressure fluctuation, flow velocity fluctuation) of a guess-type flowmeter.
【0002】[0002]
【従来の技術】従来より、電子式ガスメータ等の流量計
測に使用されている流量計としては、超音波式やフルイ
ディック式等の流量計が広く使用されている。例えば、
超音波式のガス流量計の基本原理について簡単に説明す
ると、図6に示すように、超音波式流量計20は、ガス
流路内に一定距離だけ離れて配置された超音波周波数で
作動する、例えば圧電式振動子からなる2つの音響トラ
ンスジューサ21,23と、超音波が伝搬する伝搬管路
22とを有し、例えば、まずガス流入側のトランスジュ
ーサ21から超音波信号を発生させ、ガス流出側のトラ
ンスジューサ23に受信させてトランスジューサ間での
超音波信号のガス流方向の伝搬時間t1を計測する。2. Description of the Related Art Conventionally, as a flow meter used for measuring a flow rate of an electronic gas meter or the like, a flow meter of an ultrasonic type or a fluidic type has been widely used. For example,
Briefly describing the basic principle of the ultrasonic gas flow meter, as shown in FIG. 6, the ultrasonic flow meter 20 operates at an ultrasonic frequency which is arranged at a fixed distance in the gas flow path. For example, two acoustic transducers 21 and 23 composed of piezoelectric vibrators and a propagation pipe 22 through which ultrasonic waves propagate. For example, first, an ultrasonic signal is generated from the transducer 21 on the gas inflow side, and gas outflow occurs. The transmission time t1 of the ultrasonic signal between the transducers in the gas flow direction is measured by the transducer 23 on the side.
【0003】次に、双方のトランスジューサを切換え
て、ガス流出側のトランスジューサ23から超音波信号
を発生させ、ガス流入側のトランスジューサ21に受信
させて該ガス流方向とは逆方向の伝搬時間t2を計測す
る。この計測した2つの伝搬時間t1,t2の伝搬時間差
に基づいて伝搬管路22内を流れているガスの流速vを
間欠的に求め、この流速vに伝搬経路22の断面積を乗
じて瞬時流量を求める。そして、この瞬時流量に一定の
計測間隔であるサンプリング時間を乗じて通過流量を求
め、この通過流量を積算して求めた積算流量を表示する
ものである。Next, both transducers are switched to generate an ultrasonic signal from the transducer 23 on the gas outflow side, and the ultrasonic signal is received by the transducer 21 on the gas inflow side, so that the propagation time t2 in the direction opposite to the gas flow direction is measured. measure. Based on the difference between the two measured propagation times t1 and t2, the flow velocity v of the gas flowing in the propagation pipe 22 is intermittently obtained, and the flow velocity v is multiplied by the cross-sectional area of the propagation path 22 to obtain the instantaneous flow rate. Ask for. Then, the passing flow rate is obtained by multiplying the instantaneous flow rate by a sampling time that is a constant measurement interval, and the integrated flow rate obtained by integrating the passing flow rates is displayed.
【0004】[0004]
【発明が解決しようとする課題】ところで、この種の流
量計を通じて供給されるガス等の流体を消費するガスヒ
ートポンプ(GHP)等の燃焼器は、使用中に供給ガス
に圧力変動や流速変動の脈動を生じさせるものがある。
例えば、図7(a)に示すように、燃焼器30のしよう
によってガス圧に変動を生じ、その脈動25が流量計2
0の下流側から流量計20内に伝搬してきて計測誤差の
原因となる。すなわち、図8(a)に示すように、GH
Pの運転やガス遮断等により急激な圧力変動があると、
流量計20の流入側圧力Pinと流出側圧力Poutの圧力
差ΔPが計測時間によって異なってくる(ΔP1≠ΔP
2)。これにより、流速が変化して計測誤差を生じさせ
る。By the way, a combustor such as a gas heat pump (GHP) that consumes a fluid such as a gas supplied through a flow meter of this type has a pressure fluctuation or a flow velocity fluctuation in a supplied gas during use. Some cause pulsation.
For example, as shown in FIG. 7A, the gas pressure fluctuates due to the use of the combustor 30 and the pulsation 25 causes
0 propagates into the flow meter 20 from the downstream side and causes a measurement error. That is, as shown in FIG.
If there is a sudden pressure change due to the operation of P or gas shutoff,
The pressure difference ΔP between the inflow side pressure Pin and the outflow side pressure Pout of the flow meter 20 differs depending on the measurement time (ΔP1 ≠ ΔP
2). As a result, the flow velocity changes, causing a measurement error.
【0005】また、図7(b)に示すように隣接する2
つの流量計20A,20Bの内、流量計20Bは、上述
したように燃焼器30Bからの脈動25Bが下流側から
伝搬するとともに、燃焼器30Aからの脈動25Aが上
流側から流量計内に伝搬して、さらに大きな計測誤差を
発生させる原因となっていた。すなわち、極端な場合に
なると図8(b)に示すように、計測時間によっては流
入側圧力Pinよりも流出側圧力Poutの方が大きくなっ
てしまい(ΔP3<0)、逆流が発生してさらに大きな
計測誤差を生じ、特に積算値の演算に大きな影響を及ぼ
すという問題があった。[0005] As shown in FIG.
Among the two flow meters 20A and 20B, the flow meter 20B is configured such that the pulsation 25B from the combustor 30B propagates from the downstream side and the pulsation 25A from the combustor 30A propagates from the upstream side into the flow meter as described above. As a result, a larger measurement error is caused. That is, in an extreme case, as shown in FIG. 8B, depending on the measurement time, the outflow side pressure Pout becomes larger than the inflow side pressure Pin (ΔP3 <0), and a backflow occurs. There is a problem in that a large measurement error occurs, and particularly has a great influence on the calculation of the integrated value.
【0006】さらに詳しく説明すると、図9に示すよう
に圧力変動等が発生すると、これが原因でガス流に、時
間と共にガス流速が変化する脈動流を生じるようにな
る。このような脈動流の生じているガス流の流速vを上
述したような流量計により一定のサンプリング間隔Δt
によって測り、この計測した流速vにサンプリング時間
Δtを乗じて通過流量を求めた場合、図中斜線を施した
部分が誤差となり、通過流量を積算して求めた積算流量
は、実際のガス使用料と違った積算値となる。More specifically, when a pressure fluctuation or the like occurs as shown in FIG. 9, the gas flow causes a pulsating flow in which the gas flow rate changes with time due to the fluctuation. The flow velocity v of the gas flow in which such a pulsating flow is generated is measured at a constant sampling interval Δt by a flow meter as described above.
When the flow rate is obtained by multiplying the measured flow velocity v by the sampling time Δt, the hatched portion in the figure becomes an error, and the integrated flow rate obtained by integrating the flow rate is the actual gas usage rate. It will be a different integrated value.
【0007】このような計測誤差の問題は、サンプリン
グ時間Δtよりも小さい周期の脈動流が生じているとき
には、より一層大きくなる。このような問題を解消する
には、サンプリング時間Δtを短くすればよいが、この
ようにすると消費電流が多くなってしまう。したがっ
て、電池を電源とした場合には、電池交換の間隔が短く
なるという問題をも生じることとなる。The problem of the measurement error becomes even greater when a pulsating flow having a period smaller than the sampling time Δt is generated. To solve such a problem, the sampling time Δt may be shortened. However, in this case, the current consumption increases. Therefore, when a battery is used as a power source, there is also a problem that the interval between battery replacement becomes short.
【0008】本発明は、前述した問題点に鑑みてなされ
たものであり、その目的は脈動流の影響を軽減して、正
確な流量計測を行うことのできる流量計および流量計測
方法を提供することにある。The present invention has been made in view of the above-described problems, and has as its object to provide a flow meter and a flow measurement method capable of reducing the influence of a pulsating flow and performing accurate flow measurement. It is in.
【0009】[0009]
【課題を解決するための手段】前述した目的を達成する
ために、本発明の流量計は、請求項1に記載したよう
に、流路中の流速を間欠的に計測して積算流量を推測す
る流量計測手段を備えた推量式の流量計において、当該
流量計の流入口近傍の圧力と流出口近傍の圧力との圧力
差を検出する圧力計測手段と、前記圧力計測手段による
圧力差を流量値に変換する変換テーブルと、前記流量計
測手段による流量計測結果が所定流量以下のときに、前
記変換テーブルによって求められた流量値を当該流量計
の流量計測結果とする制御手段とを備えたものである。In order to achieve the above-mentioned object, a flow meter according to the present invention intermittently measures a flow velocity in a flow path to estimate an integrated flow rate. A flow meter of a guessing type provided with a flow rate measuring means, a pressure measuring means for detecting a pressure difference between a pressure near an inlet and a pressure near an outlet of the flow meter; A conversion table for converting the flow rate into a value, and control means for setting a flow rate value obtained by the conversion table to a flow rate measurement result of the flow meter when a flow rate measurement result by the flow rate measurement means is equal to or less than a predetermined flow rate. It is.
【0010】また、請求項2に係る流量計は、流路中の
流速を間欠的に計測して積算流量を推測する流量計測手
段を備えた推量式の流量計において、当該流量計の流入
口近傍の圧力と流出口近傍の圧力との圧力差を検出する
圧力計測手段と、前記圧力計測手段による圧力差を流量
値に変換する変換テーブルと、前記流量計測手段による
流量計測結果に基づき流量の変化量を検出する流量変化
量検出手段と、前記流量変化量検出手段による流量の変
化量が所定量以上のときに、前記変換テーブルによって
求められた流量値を当該流量計の流量計測結果とする制
御手段とを備えたものである。According to a second aspect of the present invention, there is provided a flow meter provided with a flow rate measuring means for intermittently measuring a flow velocity in a flow path and estimating an integrated flow rate. A pressure measuring means for detecting a pressure difference between the pressure in the vicinity and the pressure in the vicinity of the outlet; a conversion table for converting the pressure difference by the pressure measuring means into a flow value; The flow rate change amount detecting means for detecting the change amount, and when the change amount of the flow rate by the flow rate change amount detecting means is equal to or more than a predetermined amount, the flow rate value obtained by the conversion table is used as the flow rate measurement result of the flow meter. Control means.
【0011】また、請求項3に係る流量計測方法は、流
路中の流速を間欠的に計測して積算流量を推測する流量
計測手段と、当該流量計の流入口近傍の圧力と流出口近
傍の圧力との圧力差を検出する圧力計測手段とを備えた
推量式流量計の流量計測方法において、前記圧力計測手
段による圧力差を変換テーブルに基づき流量値に変換す
る変換ステップと、前記流量計測手段による流量計測結
果が所定流量以下か否かを判定する第1判定ステップ
と、前記第1判定ステップで所定流量以下と判定された
ときに、前記変換ステップにおいて求められた流量値を
当該流量計の流量計測結果とする出力ステップとを備え
たものである。According to a third aspect of the present invention, there is provided a flow rate measuring method, comprising: a flow rate measuring means for intermittently measuring a flow velocity in a flow path and estimating an integrated flow rate; A flow rate measuring method for an inferential flow meter having a pressure measuring means for detecting a pressure difference from the pressure of the pressure, wherein a conversion step of converting the pressure difference by the pressure measuring means into a flow rate value based on a conversion table; A first determining step of determining whether or not the flow rate measurement result by the means is equal to or less than a predetermined flow rate; and, when the first determining step determines that the flow rate is equal to or less than the predetermined flow rate, the flow rate value obtained in the conversion step is determined by the flow meter. And an output step as a flow measurement result.
【0012】また、請求項4に係る流量計測方法は、流
路中の流速を間欠的に計測して積算流量を推測する流量
計測手段と、当該流量計の流入口近傍の圧力と流出口近
傍の圧力との圧力差を検出する圧力計測手段とを備えた
推量式流量計の流量計測方法において、前記圧力計測手
段による圧力差を変換テーブルに基づき流量値に変換す
る変換ステップと、前記流量計測手段による流量計測結
果に基づき流量の変化量を検出する流量変化量検出ステ
ップと、前記流量変化量検出ステップによる流量の変化
量が所定量以上か否かを判定する第2判定ステップと、
前記第2判定ステップで所定量以上と判定されたとき
に、前記変換ステップによって求められた流量値を当該
流量計の流量計測結果とする出力ステップとを備えたも
のである。According to a fourth aspect of the present invention, there is provided a flow rate measuring method, comprising: a flow rate measuring means for intermittently measuring a flow velocity in a flow path and estimating an integrated flow rate; A flow rate measuring method for an inferential flow meter having a pressure measuring means for detecting a pressure difference from the pressure of the pressure, wherein a conversion step of converting the pressure difference by the pressure measuring means into a flow rate value based on a conversion table; A flow rate change amount detecting step of detecting a change amount of the flow rate based on the flow rate measurement result by the means, and a second determining step of determining whether the change amount of the flow rate by the flow rate change amount detecting step is equal to or more than a predetermined amount,
An output step of setting the flow rate value obtained in the conversion step to a flow rate measurement result of the flow meter when the second determination step determines that the flow rate is equal to or more than a predetermined amount.
【0013】また、請求項5に係る流量計測方法は、流
路中の流速を間欠的に計測して積算流量を推測する流量
計測手段と、当該流量計の流入口近傍の圧力と流出口近
傍の圧力との圧力差を検出する圧力計測手段とを備えた
推量式流量計の流量計測方法において、前記圧力計測手
段による圧力差を変換テーブルに基づき流量値に変換す
る変換ステップと、前記流量計測手段による流量計測結
果が所定流量以下か否かを判定する第1判定ステップ
と、前記流量計測手段による流量計測結果に基づき流量
の変化量を検出する流量変化量検出ステップと、前記流
量変化量検出ステップによる流量の変化量が所定量以上
か否かを判定する第2判定ステップと、前記第1判定ス
テップで所定流量以下と判定されたか、または、前記第
2判定ステップで所定量以上と判定されたときに、前記
変換ステップによって求められた流量値を当該流量計の
流量計測結果とする出力ステップとを備えたものであ
る。According to a fifth aspect of the present invention, there is provided a flow rate measuring method, comprising: a flow rate measuring means for intermittently measuring a flow velocity in a flow path and estimating an integrated flow rate; A flow rate measuring method for an inferential flow meter having a pressure measuring means for detecting a pressure difference from the pressure of the pressure, wherein a conversion step of converting the pressure difference by the pressure measuring means into a flow rate value based on a conversion table; A first determination step of determining whether a flow measurement result by the means is equal to or less than a predetermined flow rate, a flow change detection step of detecting a flow change amount based on the flow measurement result by the flow measurement means, and the flow change detection A second determining step of determining whether or not the amount of change in the flow rate by the step is equal to or greater than a predetermined amount; and determining whether the flow rate is equal to or less than the predetermined flow rate in the first determining step or a predetermined value in the second determining step. When it is determined that the amount or more, the flow rate value determined by said conversion step is obtained and an output step for the flow rate measurement result of the flow meter.
【0014】本発明の請求項1に係る流量計および請求
項3に係る流量計測方法では、流量計測手段によって流
路中の流速を間欠的に計測して積算流量を推測すると共
に、並行して圧力計測手段によって当該流量計の流入口
近傍の圧力と流出口近傍の圧力との圧力差を検出し、該
圧力計測手段による圧力差を変換テーブルによって流量
値に変換しておき(変換ステップ)、制御手段では、流
量計測手段による流量計測結果が所定流量以下のとき
(第1判定ステップ)に、変換テーブルによって求めら
れた流量値を当該流量計の流量計測結果として(出力ス
テップ)いる。このように、圧力変動や流速変動の脈動
流の影響が特に顕著であるとされる低流量時に、圧力変
動や流速変動の脈動流の影響をほとんど受けない計測手
法、すなわち圧力計測手段で検出した圧力差を変換テー
ブルによって流量値に変換する計測手法を用いて流量を
求めるので、流量計測の計測精度を向上させることがで
きる。特に圧力監視機能を備えた電子式ガスメータ等に
適用される場合には、低流量時の脈動流による誤った警
告の発行等を抑制することができ、圧力監視機能の信頼
性を高めることができる。In the flow meter according to the first aspect of the present invention and the flow rate measuring method according to the third aspect, the flow rate in the flow path is intermittently measured by the flow rate measuring means to estimate the integrated flow rate. The pressure difference between the pressure near the inlet and the pressure near the outlet of the flow meter is detected by the pressure measuring means, and the pressure difference by the pressure measuring means is converted into a flow rate value by a conversion table (conversion step). When the flow rate measurement result by the flow rate measuring means is equal to or less than the predetermined flow rate (first determination step), the control means uses the flow rate value obtained by the conversion table as a flow rate measurement result of the flow meter (output step). As described above, at a low flow rate where the influence of the pulsating flow of the pressure fluctuation and the flow velocity fluctuation is particularly remarkable, the measurement method which is hardly affected by the pulsating flow of the pressure fluctuation and the flow velocity fluctuation, that is, the detection is performed by the pressure measuring means. Since the flow rate is obtained by using a measurement method of converting the pressure difference into a flow rate value using a conversion table, the measurement accuracy of the flow rate measurement can be improved. In particular, when applied to an electronic gas meter or the like having a pressure monitoring function, it is possible to suppress the issuance of an erroneous warning due to a pulsating flow at a low flow rate, and to enhance the reliability of the pressure monitoring function. .
【0015】また、本発明の請求項2に係る流量計およ
び請求項4に係る流量計測方法では、流量計測手段によ
って流路中の流速を間欠的に計測して積算流量を推測す
ると共に、並行して圧力計測手段によって当該流量計の
流入口近傍の圧力と流出口近傍の圧力との圧力差を検出
し、該圧力計測手段による圧力差を変換テーブルによっ
て流量値に変換しておき(変換ステップ)、流量変化量
検出手段により流量計測手段による流量計測結果に基づ
き流量の変化量を検出(流量変化量検出ステップ)した
後、制御手段では、流量変化量検出手段による流量の変
化量が所定量以上のとき(第2判定ステップ)に、前記
変換テーブルによって求められた流量値を当該流量計の
流量計測結果として(出力ステップ)いる。このよう
に、流量変化量の検出に基づいて圧力変動や流速変動の
脈動流が特に顕著である時に、圧力変動や流速変動の脈
動流の影響をほとんど受けない計測手法、すなわち圧力
計測手段で検出した圧力差を変換テーブルによって流量
値に変換する計測手法を用いて流量を求めるので、流量
計測および流量積算の計測精度を向上させることができ
る。In the flow meter according to the second aspect of the present invention and the flow rate measuring method according to the fourth aspect, the flow rate in the flow path is intermittently measured by the flow rate measuring means to estimate the integrated flow rate, and the parallel flow rate is estimated. Then, the pressure difference between the pressure near the inlet and the pressure near the outlet of the flowmeter is detected by the pressure measuring means, and the pressure difference by the pressure measuring means is converted into a flow rate value by a conversion table (conversion step). After detecting the amount of change in the flow rate based on the flow rate measurement result by the flow rate measuring means by the flow rate change amount detecting means (flow rate change amount detecting step), the control means sets the flow rate change amount by the flow rate change amount detecting means to a predetermined amount. At the time (second determination step), the flow rate value obtained by the conversion table is used as the flow measurement result of the flow meter (output step). As described above, when the pulsating flow of the pressure fluctuation or the flow velocity fluctuation is particularly remarkable based on the detection of the flow rate change amount, the measurement method which is hardly affected by the pulsating flow of the pressure fluctuation or the flow velocity fluctuation, that is, the detection is performed by the pressure measuring means. Since the flow rate is obtained by using the measurement method of converting the pressure difference into the flow value by the conversion table, the measurement accuracy of the flow rate measurement and the flow rate integration can be improved.
【0016】さらに本発明の請求項5に係る流量計測方
法では、流量計測手段によって流路中の流速を間欠的に
計測して積算流量を推測すると共に、並行して圧力計測
手段によって当該流量計の流入口近傍の圧力と流出口近
傍の圧力との圧力差を検出し、変換ステップにより圧力
計測手段による圧力差を変換テーブルに基づき流量値に
変換しておき、第1判定ステップで流量計測手段による
流量計測結果が所定流量以下か否かを判定し、流量変化
量検出ステップで流量計測手段による流量計測結果に基
づき流量の変化量を検出し、第2判定ステップで流量変
化量検出ステップによる流量の変化量が所定量以上か否
かを判定し、さらに出力ステップでは、第1判定ステッ
プで所定流量以下と判定されたか、または、第2判定ス
テップで所定量以上と判定されたときに、変換ステップ
によって求められた流量値を当該流量計の流量計測結果
としている。このように、圧力変動や流速変動の脈動流
の影響が特に顕著であるとされる低流量時、或いは、流
量変化量の検出に基づいて圧力変動や流速変動の脈動流
が特に顕著である時に、圧力変動や流速変動の脈動流の
影響をほとんど受けない計測手法、すなわち圧力計測手
段で検出した圧力差を変換テーブルによって流量値に変
換する計測手法を用いて流量を求めるので、流量計測お
よび流量積算の計測精度を向上させることができる。特
に圧力監視機能を備えた電子式ガスメータ等に適用され
る場合には、低流量時の脈動流による誤った警告の発行
等を抑制することができ、圧力監視機能の信頼性も高め
ることができる。Further, in the flow rate measuring method according to the present invention, the flow rate in the flow path is intermittently measured by the flow rate measuring means to estimate the integrated flow rate, and in parallel, the flow rate is measured by the pressure measuring means. The pressure difference between the pressure near the inlet and the pressure near the outlet is detected, and the pressure difference by the pressure measuring means is converted into a flow value based on a conversion table in a conversion step, and the flow measurement means is determined in a first determination step. It is determined whether or not the flow rate measurement result is equal to or less than a predetermined flow rate, a flow rate change is detected based on the flow rate measurement result by the flow rate measuring means in the flow rate change detection step, and the flow rate is determined in the flow rate change detection step in the second determination step In the output step, it is determined whether the flow rate is equal to or less than the predetermined amount, or in the second determination step, the flow rate is equal to or less than the predetermined amount. And when it is determined, the flow rate value obtained by the conversion step has a flow rate measurement result of the flow meter. As described above, at a low flow rate where the influence of the pulsating flow of the pressure fluctuation or the flow velocity fluctuation is particularly remarkable, or when the pulsating flow of the pressure fluctuation or the flow velocity fluctuation is particularly prominent based on the detection of the flow rate change amount. The flow rate is determined using a measurement method that is hardly affected by the pulsating flow of pressure fluctuations and flow velocity fluctuations, that is, a measurement method that converts the pressure difference detected by the pressure measurement means into a flow rate value using a conversion table. It is possible to improve the integration measurement accuracy. In particular, when applied to an electronic gas meter or the like having a pressure monitoring function, it is possible to suppress the issuance of an erroneous warning due to a pulsating flow at a low flow rate, and to enhance the reliability of the pressure monitoring function. .
【0017】[0017]
【発明の実施の形態】以下、本発明に係る流量計および
流量計測方法の実施の形態例について、図1乃至図5を
参照して詳細に説明する。ここで、図1は本発明の実施
形態に係る流量計の基本的な構成を示す構成図であり、
図2は実施形態の流量計の一構成例を例示する構成図、
図3は実施形態の流量計の変換テーブルの内容を説明す
る説明図、図4は実施形態の流量計の流量計測方法の手
順を説明するフローチャート、図5は圧力変動や流速変
動の脈動流の発生時において検出される圧力差や流速の
特性を説明する説明図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a flow meter and a flow measuring method according to the present invention will be described below in detail with reference to FIGS. Here, FIG. 1 is a configuration diagram showing a basic configuration of the flow meter according to the embodiment of the present invention,
FIG. 2 is a configuration diagram illustrating a configuration example of a flow meter according to the embodiment;
FIG. 3 is an explanatory diagram illustrating the contents of a conversion table of the flow meter according to the embodiment. FIG. 4 is a flowchart illustrating a procedure of a flow measurement method of the flow meter according to the embodiment. FIG. 9 is an explanatory diagram illustrating characteristics of a pressure difference and a flow velocity detected at the time of occurrence.
【0018】本実施形態の流量計について、図1を参照
して説明すると、流量計は、流量計測手段1、圧力計測
手段2、変換テーブル3、流量変化量検出手段4および
制御手段5を備えて構成されている。The flow meter of the present embodiment will be described with reference to FIG. 1. The flow meter includes a flow rate measuring means 1, a pressure measuring means 2, a conversion table 3, a flow rate change detecting means 4, and a control means 5. It is configured.
【0019】流量計測手段1は、流路中の流速を間欠的
に計測して積算流量を推測するもので、従来例(図4参
照)と同等の超音波式流量計である。すなわち、図2に
示すように、流路10内に一定距離だけ離れて配置され
た超音波周波数で作動する圧電式振動子からなる2つの
音響トランスジューサ21,23と、超音波が伝搬する
伝搬管路22とを具備した構成で、その計測の基本原理
も従来例で説明したものと同等である。The flow rate measuring means 1 intermittently measures the flow velocity in the flow path and estimates the integrated flow rate, and is an ultrasonic flow meter equivalent to the conventional example (see FIG. 4). That is, as shown in FIG. 2, two acoustic transducers 21 and 23, each of which is a piezoelectric vibrator operating at an ultrasonic frequency and arranged at a fixed distance in the flow path 10, and a propagation tube through which the ultrasonic waves propagate. With the configuration including the path 22, the basic principle of the measurement is the same as that described in the conventional example.
【0020】また、圧力計測手段2は、当該流量計の流
入口11近傍の圧力と流出口12近傍の圧力との圧力差
を検出するもので、圧力センサ等によって実現される。
この圧力センサは、従来例(図4参照)においても入口
近傍に配置されており、当該流量計が電子式ガスメータ
等に適用される場合に、ガス流路におけるガス圧力を監
視して保安の向上を図る圧力監視機能を具現している。
この圧力監視機能には、例えば、圧力式微小漏洩警告、
調整圧力異常警告、閉塞圧力異常警告、圧力低下遮断、
漏洩検査、調整圧力データ記憶等がある。The pressure measuring means 2 detects a pressure difference between the pressure near the inlet 11 and the pressure near the outlet 12 of the flow meter, and is realized by a pressure sensor or the like.
This pressure sensor is also disposed near the inlet in the conventional example (see FIG. 4), and when the flow meter is applied to an electronic gas meter or the like, the gas pressure in the gas flow path is monitored to improve security. The pressure monitoring function is implemented.
This pressure monitoring function includes, for example, pressure-type micro leak warning,
Adjustment pressure abnormality warning, blockage pressure abnormality warning, pressure drop shutoff,
There are leak inspection, adjustment pressure data storage, etc.
【0021】すなわち本実施形態の流量計では、従来か
ら流量計内に配されていた圧力センサ等を、図2に示す
ように、流量計測手段1によって流量を計測する流量計
測室7とは別に設けられた圧力計測室6に圧力計測手段
2として配置して、流入側圧力Pinと流出側圧力Pout
との圧力差ΔP(圧力損失)を検出しようとするもので
ある。なお、圧力センサ等は、従来例と同様に圧力監視
機能を実現するための圧力監視手段としても活用され
る。また、図2に示した本実施形態の流量計の構造は、
従来の上流室および下流室の2室、並びに計測部を備え
た嵌合形態に対して、従来の上流室および下流室を流量
計測室6とし圧力計測室6を付加した簡単な構造である
ので、従来の流量計に比較して製造コストを大幅に上昇
させることなく製造することができる。That is, in the flow meter of the present embodiment, the pressure sensor and the like conventionally arranged in the flow meter are replaced with a flow measurement chamber 7 for measuring the flow rate by the flow measurement means 1 as shown in FIG. The pressure measuring means 2 is disposed in the pressure measuring chamber 6 provided therein, and the inflow side pressure Pin and the outflow side pressure Pout
Is to detect a pressure difference ΔP (pressure loss). The pressure sensor and the like are also used as pressure monitoring means for realizing a pressure monitoring function as in the conventional example. Further, the structure of the flow meter of the present embodiment shown in FIG.
Since the conventional upstream chamber and the downstream chamber are combined with the conventional upstream chamber and the downstream chamber, and the fitting form including the measuring section, the conventional upstream chamber and the downstream chamber are the flow rate measuring chamber 6 and the pressure measuring chamber 6 is added to the simple structure. It can be manufactured without significantly increasing the manufacturing cost as compared with the conventional flow meter.
【0022】次に、変換テーブル3は、圧力計測手段2
による圧力差を流量値に変換するもので、ROMやRA
M内に記憶された表形式のデータによって実現される。
すなわち、流入側圧力Pinと流出側圧力Poutとの圧力
差ΔPおよび流量PQの関係は、図3に示すような特性
を有するものであり、該特性を表形式データで表現した
ものが変換テーブル3となる。なお、図3に示したよう
な特性は実験によって求めることが可能であり、予め行
われる実験によって得られた特性データに基づいて表形
式データを形成して、これをROMやRAM内に記憶し
ておけばよい。Next, the conversion table 3 stores the pressure measuring means 2
Is to convert the pressure difference caused by the
This is realized by tabular data stored in M.
That is, the relationship between the pressure difference ΔP between the inflow side pressure Pin and the outflow side pressure Pout and the flow rate PQ has characteristics as shown in FIG. Becomes The characteristics as shown in FIG. 3 can be obtained by an experiment. Tabular data is formed based on characteristic data obtained by an experiment conducted in advance, and this is stored in a ROM or a RAM. It should be left.
【0023】また、流量変化量検出手段4は、流量計測
手段1による流量計測結果SQに基づき流量の変化量Δ
SQを検出するものであり、制御手段5は、流量計測手
段1による流量計測結果SQが所定流量以下のとき、或
いは、流量変化量検出手段4による流量の変化量ΔSQ
が所定量以上のときに、変換テーブル3によって求めら
れた流量値PQを当該流量計の流量計測結果Qとするも
のである。流量変化量検出手段4および制御手段5は、
マイクロプロセッサ(MPU)上で実行されるソフトウ
ェアプログラムで実現される。The flow rate change detecting means 4 calculates the flow rate change Δ based on the flow rate measurement result SQ by the flow rate measuring means 1.
The control means 5 detects when the flow rate measurement result SQ by the flow rate measurement means 1 is equal to or less than a predetermined flow rate, or when the flow rate change amount ΔSQ
Is greater than or equal to a predetermined amount, the flow value PQ obtained by the conversion table 3 is used as the flow measurement result Q of the flow meter. The flow rate change amount detection means 4 and the control means 5
It is realized by a software program executed on a microprocessor (MPU).
【0024】次に、本実施形態の流量計における流量計
測方法を、図4のフローチャートを参照して説明する。
まずステップS401では、流量計測手段1によって流
路10中の流速を間欠的に計測する。これと並行してス
テップS411では、圧力計測手段2によって当該流量
計の流入口11近傍の流入側圧力Pinと流出口12近傍
の流出側圧力Poutとの圧力差ΔPを検出する。流量計
測手段1によって流速を計測するサンプリング間隔Δt
は、消費電力を考慮した上でなるべく短く設定するのが
望ましい。なお、サンプリング間隔Δtは、従来例のよ
うに固定としても良いし、可変させる(例えば所定の範
囲でランダム的に変化させる)ようにしても良い。Next, a flow rate measuring method in the flow meter according to the present embodiment will be described with reference to the flowchart of FIG.
First, in step S401, the flow rate in the flow path 10 is intermittently measured by the flow rate measuring means 1. In parallel with this, at step S411, the pressure measuring means 2 detects a pressure difference ΔP between the inflow side pressure Pin near the inflow port 11 and the outflow side pressure Pout near the outflow port 12 of the flowmeter. Sampling interval Δt for measuring flow velocity by flow rate measuring means 1
Is preferably set as short as possible in consideration of power consumption. The sampling interval Δt may be fixed as in the conventional example, or may be variable (for example, randomly changed within a predetermined range).
【0025】次に、ステップS402(第1判定ステッ
プ)では、流量計測手段1による流量計測結果SQが所
定流量以下か否かを判定し、所定流量以下のときにはス
テップS412に、所定流量を越えているときはステッ
プS403にそれぞれ進む。ここで所定流量は、例えば
電子式ガスメータ等に適用される場合には0.05Qma
x(Qmaxは最大流量)であり、0.05Qmax以下の場
合に低流量と判断される。具体的に、例えば2.5m3
/h型のものでは125L/h以下が低流量として扱わ
れることになる。Next, in step S402 (first determination step), it is determined whether or not the flow rate measurement result SQ by the flow rate measuring means 1 is equal to or less than a predetermined flow rate. If yes, the process proceeds to step S403. Here, the predetermined flow rate is 0.05 Qma when applied to an electronic gas meter, for example.
x (Qmax is the maximum flow rate), and when it is 0.05 Qmax or less, it is determined that the flow rate is low. Specifically, for example, 2.5 m 3
For the / h type, a flow rate of 125 L / h or less is treated as a low flow rate.
【0026】また、ステップS403(流量変化量検出
ステップ)では、流量変化量検出手段4により流量計測
手段1による流量計測結果SQに基づき流量の変化量Δ
SQを検出する。そして、ステップS404(第2判定
ステップ)では、検出された流量の変化量ΔSQが所定
量以上か否かを判定し、所定量以上のときにはステップ
S412に、所定量未満のときはステップS405にそ
れぞれ進む。すなわち、流量の変化量ΔSQが所定量以
上となるのは、速度変動値が大きい脈動流が発生してい
る場合であり、第2判定ステップで脈動流の発生の有無
を判定している。In step S403 (a flow rate change detection step), the flow rate change amount detection means 4 determines the flow rate change amount Δ based on the flow rate measurement result SQ by the flow rate measurement means 1.
SQ is detected. Then, in step S404 (second determination step), it is determined whether or not the detected change amount ΔSQ of the flow rate is equal to or more than a predetermined amount, and if it is equal to or more than the predetermined amount, the process proceeds to step S412, and if less than the predetermined amount, to step S405. move on. That is, the change amount ΔSQ of the flow rate becomes equal to or more than the predetermined amount when a pulsating flow having a large speed fluctuation value is generated, and the presence or absence of the pulsating flow is determined in the second determination step.
【0027】したがって、低流量か或いは脈動流が発生
していると判断された場合にはステップS412に進む
ことになるが、ステップS412(変換ステップ)で
は、圧力計測手段2による圧力差ΔPを変換テーブル3
に基づき流量値PQに変換し、さらにステップS413
(出力ステップ)で、変換された流量値PQを当該流量
計の流量計測結果Qとしている。一方、低流量ではなく
或いは脈動流が発生していないと判断された場合にはス
テップS405に進んで、流量計測手段1による流量計
測結果SQを当該流量計の流量計測結果Qとしている。
そして、さらにステップS406で計測結果の流量Qを
積算した後、再びステップS401,S411に戻る。Therefore, when it is determined that a low flow rate or a pulsating flow is generated, the process proceeds to step S412. In step S412 (conversion step), the pressure difference ΔP by the pressure measuring means 2 is converted. Table 3
Is converted to a flow value PQ based on
In (output step), the converted flow value PQ is used as the flow measurement result Q of the flow meter. On the other hand, when it is determined that the flow rate is not low or that no pulsating flow is generated, the process proceeds to step S405, and the flow rate measurement result SQ of the flow rate measuring unit 1 is set as the flow rate measurement result Q of the flow meter.
Then, after further integrating the flow rate Q of the measurement result in step S406, the process returns to steps S401 and S411 again.
【0028】以上詳細に説明したように、本実施形態の
流量計および流量計測方法では、流量計測手段1によっ
て流路中の流速を間欠的に計測して積算流量を推測する
と共に、並行して圧力計測手段2によって流入口11近
傍の流入側圧力Pinと流出口12近傍の流出側圧力Pou
tとの圧力差ΔPを検出し、変換ステップ(ステップS
412)により圧力計測手段2による圧力差ΔPを変換
テーブル3に基づき流量値PQに変換しておき、流量変
化量検出ステップ(ステップS403)では流量変化量
検出手段4により流量計測結果SQに基づき流量の変化
量ΔSQを検出し、さらに制御手段5により、第1判定
ステップ(ステップ402)で流量計測手段1による流
量計測結果SQが所定流量以下か否かを判定し、また第
2判定ステップ(ステップS404)で流量の変化量Δ
SQが所定量以上か否かを判定し、さらに出力ステップ
(ステップS413)で第1判定ステップで所定流量以
下と判定されたか、または、第2判定ステップで所定量
以上と判定されたときに、変換ステップによって求めら
れた流量値PQを当該流量計の流量計測結果とする。As described in detail above, in the flow meter and the flow rate measuring method of the present embodiment, the flow rate in the flow path is intermittently measured by the flow rate measuring means 1 to estimate the integrated flow rate, and the flow rate is measured in parallel. By the pressure measuring means 2, the inflow side pressure Pin near the inflow port 11 and the outflow side pressure Pou near the outflow port 12 are measured.
The pressure difference ΔP from t is detected, and the conversion step (step S
In step 412), the pressure difference ΔP by the pressure measuring means 2 is converted into a flow rate value PQ based on the conversion table 3, and in the flow rate change detecting step (step S403), the flow rate is determined by the flow rate changing detecting means 4 based on the flow rate measurement result SQ. , And the control means 5 determines in a first determination step (step 402) whether or not the flow rate measurement result SQ by the flow rate measurement means 1 is equal to or less than a predetermined flow rate, and a second determination step (step 402). In S404), the flow rate change amount Δ
It is determined whether or not SQ is equal to or more than a predetermined amount. Further, when it is determined in the output step (step S413) that the flow rate is equal to or less than the predetermined amount in the first determination step, or when it is determined in the second determination step that the amount is equal to or more than the predetermined amount, The flow value PQ obtained in the conversion step is used as a flow measurement result of the flow meter.
【0029】このように、本実施形態の流量計および流
量計測方法では、圧力変動や流速変動の脈動流の影響が
特に顕著であるとされる低流量時、或いは、流量変化量
ΔSQの検出に基づいて圧力変動や流速変動の脈動流が
発生していると判断された時に、圧力変動や流速変動の
脈動流の影響をほとんど受けない計測手法、すなわち圧
力計測手段2で検出した圧力差ΔPを変換テーブル3に
よって流量値PQに変換する計測手法を用いて流量を求
めるので、流量計測および流量積算の計測精度を向上さ
せることができる。As described above, the flow meter and the flow rate measuring method of the present embodiment are used for detecting a low flow rate where the influence of the pulsating flow of the pressure fluctuation and the flow velocity fluctuation is particularly remarkable, or for detecting the flow rate variation ΔSQ. When it is determined that the pulsating flow of the pressure fluctuation or the flow velocity fluctuation is generated based on the measurement method, the pressure difference ΔP detected by the pressure measuring means 2 is hardly influenced by the pulsating flow of the pressure fluctuation or the flow velocity fluctuation. Since the flow rate is obtained by using the measurement method of converting to the flow value PQ by the conversion table 3, the measurement accuracy of the flow rate measurement and the flow rate integration can be improved.
【0030】圧力計測手段2で検出した圧力差ΔPを変
換テーブル3によって流量値PQに変換する計測手法
が、圧力変動や流速変動の脈動流の影響をほとんど受け
ないことは、図5の説明図から明らかである。すなわ
ち、図5(a)に示されるような脈動流の発生(圧力変
動)に対して、流速の変動は図5(c)に示すように顕
著であるが、圧力差ΔP=Pin−Pout は図5(b)に
示すように平均化されて時間的な変動をほとんど持たな
い。つまり、原理的に圧力差ΔPは2つの物理量の差で
あって、1つの物理量としてそのまま計測される流量計
測手段1による流量計測結果SQと比較して、平均的な
値が得られ易いことによるものである。すなわち、流量
計測手段1では速度差として流速を計測していないので
平均化がされ難いのである。FIG. 5 shows that the measurement method for converting the pressure difference ΔP detected by the pressure measuring means 2 into the flow rate value PQ by the conversion table 3 is hardly affected by the pulsating flow of the pressure fluctuation and the flow velocity fluctuation. It is clear from That is, the fluctuation of the flow velocity is remarkable as shown in FIG. 5C with respect to the generation of the pulsating flow (pressure fluctuation) as shown in FIG. 5A, but the pressure difference ΔP = Pin−Pout is As shown in FIG. 5 (b), they are averaged and have little temporal variation. That is, in principle, the pressure difference ΔP is a difference between two physical quantities, and an average value is easily obtained as compared with the flow rate measurement result SQ by the flow rate measuring means 1 which is directly measured as one physical quantity. Things. That is, since the flow rate measuring means 1 does not measure the flow velocity as the velocity difference, averaging is difficult.
【0031】また特に、本実施形態の流量計が圧力監視
機能を備えた電子式ガスメータ等に適用される場合に
は、上述のように、圧力計測手段(圧力センサ等)2に
よってガス流路におけるガス圧力を監視し圧力監視機能
により保安されることになるが、ガス圧力と共に本実施
形態の流量計測方法による流量値または積算流量値をも
監視して、圧力監視機能を実現するようにすれば、脈動
流の影響が特に顕著である低流量時の誤った警告の発行
や誤った強制遮断動作等を抑制することができ、圧力監
視機能の信頼性をも高めることが可能となる。In particular, when the flow meter of the present embodiment is applied to an electronic gas meter or the like having a pressure monitoring function, as described above, the pressure measuring means (pressure sensor or the like) 2 controls the gas flow path. The gas pressure is monitored and secured by the pressure monitoring function.However, if the flow rate value or the integrated flow rate value according to the flow rate measurement method of the present embodiment is also monitored together with the gas pressure, the pressure monitoring function can be realized. In addition, it is possible to suppress the issuance of an erroneous warning or an erroneous forcible shutoff operation at a low flow rate where the influence of the pulsating flow is particularly remarkable, and it is also possible to enhance the reliability of the pressure monitoring function.
【0032】なお、以上説明した本実施形態の流量計で
は、図1および図2に示したように超音波式の流量計測
手段を想定しているが、超音波式に限定されることな
く、フルイディック式、または羽根車若しくはタービン
式といった他の流量計測手段を備えた流量計にも適用可
能である。これら他の流量計測手段についても脈動流が
伝わる限り出力にばらつきが出てくることは明白だから
である。In the flow meter of the present embodiment described above, an ultrasonic flow rate measuring means is assumed as shown in FIGS. 1 and 2. However, the flow meter is not limited to the ultrasonic type. The present invention is also applicable to a flow meter provided with another flow measuring means such as a fluidic type or an impeller or a turbine type. This is because it is obvious that the output of these other flow rate measuring means also varies as long as the pulsating flow is transmitted.
【0033】[0033]
【発明の効果】以上、説明したように、本発明の流量計
および流量計測方法によれば、流量計測手段によって流
路中の流速を間欠的に計測して積算流量を推測すると共
に、並行して圧力計測手段によって当該流量計の流入口
近傍の圧力と流出口近傍の圧力との圧力差を検出し、該
圧力計測手段による圧力差を変換テーブルによって流量
値に変換しておき(変換ステップ)、制御手段では、圧
力変動や流速変動の脈動流の影響が特に顕著であるとさ
れる低流量時、流量変化量の検出に基づいて圧力変動や
流速変動の脈動流が特に顕著である時、の少なくとも一
方の場合に、圧力変動や流速変動の脈動流の影響をほと
んど受けない計測手法、すなわち圧力計測手段で検出し
た圧力差を変換テーブルによって流量値に変換する計測
手法を用いて流量を求めることとしたので、流量計測お
よび流量積算の計測精度を向上させることができ、特に
圧力監視機能を備えた電子式ガスメータ等に適用される
場合には、低流量時の脈動流による誤った警告の発行等
を抑制することができ、圧力監視機能の信頼性を高める
ことも可能である。As described above, according to the flow meter and the flow rate measuring method of the present invention, the flow rate in the flow path is intermittently measured by the flow rate measuring means to estimate the integrated flow rate, and the flow rate is measured in parallel. The pressure difference between the pressure near the inlet and the pressure near the outlet of the flowmeter is detected by the pressure measuring means, and the pressure difference by the pressure measuring means is converted into a flow rate value by a conversion table (conversion step). In the control means, at a low flow rate where the influence of the pulsating flow of the pressure fluctuation or the flow velocity fluctuation is particularly remarkable, when the pulsating flow of the pressure fluctuation or the flow velocity fluctuation is particularly prominent based on the detection of the flow rate change amount, In at least one of the cases, the flow rate is measured by using a measurement method that is hardly affected by the pulsating flow of the pressure fluctuation or the flow velocity fluctuation, that is, a measurement method that converts the pressure difference detected by the pressure measuring means into a flow rate value using a conversion table. The accuracy of the flow rate measurement and flow rate integration can be improved because it is required to be determined.Especially when applied to an electronic gas meter with a pressure monitoring function, an erroneous warning due to a pulsating flow at a low flow rate Can be suppressed, and the reliability of the pressure monitoring function can be improved.
【図1】本発明の実施形態に係る流量計の基本的な構成
を示す構成図である。FIG. 1 is a configuration diagram showing a basic configuration of a flow meter according to an embodiment of the present invention.
【図2】実施形態の流量計の一構成例を例示する構成図
である。FIG. 2 is a configuration diagram illustrating a configuration example of a flow meter according to an embodiment;
【図3】実施形態の流量計の変換テーブルの内容を説明
する説明図である。FIG. 3 is an explanatory diagram illustrating contents of a conversion table of the flow meter according to the embodiment.
【図4】実施形態の流量計の流量計測方法の手順を説明
するフローチャートである。FIG. 4 is a flowchart illustrating a procedure of a flow measurement method of the flow meter according to the embodiment.
【図5】圧力変動や流速変動の脈動流の発生時において
検出される圧力差や流速の特性を説明する説明図であ
る。FIG. 5 is an explanatory diagram illustrating characteristics of a pressure difference and a flow velocity detected when a pulsating flow of a pressure fluctuation and a flow velocity fluctuation occurs.
【図6】超音波式のガス流量計の基本原理を説明する説
明図である。FIG. 6 is an explanatory diagram illustrating the basic principle of an ultrasonic gas flow meter.
【図7】圧力変動や流速変動の脈動流の発生を説明する
説明図である。FIG. 7 is an explanatory diagram illustrating generation of a pulsating flow of a pressure fluctuation and a flow velocity fluctuation.
【図8】圧力変動時の計測誤差の発生を説明する説明図
である。FIG. 8 is an explanatory diagram for explaining occurrence of a measurement error at the time of pressure fluctuation.
【図9】圧力変動や流速変動の脈動流の特性を説明する
説明図である。FIG. 9 is an explanatory diagram illustrating characteristics of a pulsating flow of pressure fluctuation and flow velocity fluctuation.
1 流量計測手段 2 圧力計測手段(圧力センサ) 3 変換テーブル(RAM,ROM) 4 流量変化量検出手段(MPU) 5 制御手段(MPU) 6 流量計測室 7 圧力計測室 10 流路 11 流入口 12 流出口 Pin 流入側圧力 Pout 流出側圧力 ΔP 圧力差(圧力損失) SQ,PQ 流量 ΔSQ 流量変化量 Q 流量計測結果 20,20A,20B 流量計 21,23 音響トランスジューサ 22 伝搬管路 25,25A,25B 脈動流 30,30A,30B 燃焼器 REFERENCE SIGNS LIST 1 flow rate measuring means 2 pressure measuring means (pressure sensor) 3 conversion table (RAM, ROM) 4 flow rate change detecting means (MPU) 5 control means (MPU) 6 flow rate measuring chamber 7 pressure measuring chamber 10 flow path 11 inlet 12 Outlet Pin Inflow pressure Pout Outflow pressure ΔP Pressure difference (pressure loss) SQ, PQ Flow rate ΔSQ Flow rate variation Q Flow rate measurement result 20, 20A, 20B Flow meter 21, 23 Acoustic transducer 22 Propagation pipeline 25, 25A, 25B Pulsating flow 30, 30A, 30B Combustor
Claims (5)
量を推測する流量計測手段を備えた推量式の流量計にお
いて、 当該流量計の流入口近傍の圧力と流出口近傍の圧力との
圧力差を検出する圧力計測手段と、 前記圧力計測手段による圧力差を流量値に変換する変換
テーブルと、 前記流量計測手段による流量計測結果が所定流量以下の
ときに、前記変換テーブルによって求められた流量値を
当該流量計の流量計測結果とする制御手段と、を有する
ことを特徴とする流量計。An inferential flow meter provided with a flow rate measuring means for intermittently measuring a flow velocity in a flow path and estimating an integrated flow rate, wherein a pressure near an inlet and a pressure near an outlet of the flow meter are provided. Pressure conversion means for detecting a pressure difference between the pressure measurement means, a conversion table for converting the pressure difference by the pressure measurement means to a flow rate value, when the flow rate measurement result by the flow rate measurement means is less than or equal to a predetermined flow rate, it is determined by the conversion table Control means for setting the obtained flow value as a flow measurement result of the flow meter.
量を推測する流量計測手段を備えた推量式の流量計にお
いて、 当該流量計の流入口近傍の圧力と流出口近傍の圧力との
圧力差を検出する圧力計測手段と、 前記圧力計測手段による圧力差を流量値に変換する変換
テーブルと、 前記流量計測手段による流量計測結果に基づき流量の変
化量を検出する流量変化量検出手段と、 前記流量変化量検出手段による流量の変化量が所定量以
上のときに、前記変換テーブルによって求められた流量
値を当該流量計の流量計測結果とする制御手段と、を有
することを特徴とする流量計。2. An inferential flow meter provided with flow rate measuring means for intermittently measuring a flow velocity in a flow path and estimating an integrated flow rate, comprising: a pressure near an inlet of the flow meter and a pressure near an outlet of the flow meter. Pressure measurement means for detecting a pressure difference between the pressure measurement means, a conversion table for converting the pressure difference by the pressure measurement means into a flow rate value, and a flow rate change detection for detecting a flow rate change amount based on a flow rate measurement result by the flow rate measurement means. Means, and control means for setting a flow rate value obtained by the conversion table as a flow rate measurement result of the flow meter when a change amount of the flow rate by the flow rate change amount detecting means is a predetermined amount or more. And flow meter.
量を推測する流量計測手段と、当該流量計の流入口近傍
の圧力と流出口近傍の圧力との圧力差を検出する圧力計
測手段と、を備えた推量式流量計の流量計測方法におい
て、 前記圧力計測手段による圧力差を変換テーブルに基づき
流量値に変換する変換ステップと、 前記流量計測手段による流量計測結果が所定流量以下か
否かを判定する第1判定ステップと、 前記第1判定ステップで所定流量以下と判定されたとき
に、前記変換ステップにおいて求められた流量値を当該
流量計の流量計測結果とする出力ステップと、を有する
ことを特徴とする流量計測方法。3. A flow rate measuring means for intermittently measuring a flow rate in a flow path to estimate an integrated flow rate, and a pressure for detecting a pressure difference between a pressure near an inlet and a pressure near an outlet of the flow meter. A flow rate measuring method for an inferential flow meter comprising: a converting step of converting a pressure difference by the pressure measuring means into a flow rate value based on a conversion table; and a flow rate measurement result by the flow rate measuring means being equal to or less than a predetermined flow rate. A first determination step of determining whether the flow rate is equal to or less than a predetermined flow rate in the first determination step, and an output step in which the flow rate value obtained in the conversion step is used as a flow measurement result of the flow meter. And a flow rate measuring method.
量を推測する流量計測手段と、当該流量計の流入口近傍
の圧力と流出口近傍の圧力との圧力差を検出する圧力計
測手段と、を備えた推量式流量計の流量計測方法におい
て、 前記圧力計測手段による圧力差を変換テーブルに基づき
流量値に変換する変換ステップと、 前記流量計測手段による流量計測結果に基づき流量の変
化量を検出する流量変化量検出ステップと、 前記流量変化量検出ステップによる流量の変化量が所定
量以上か否かを判定する第2判定ステップと、 前記第2判定ステップで所定量以上と判定されたとき
に、前記変換ステップによって求められた流量値を当該
流量計の流量計測結果とする出力ステップと、を有する
ことを特徴とする流量計測方法。4. A flow rate measuring means for intermittently measuring a flow rate in a flow path to estimate an integrated flow rate, and a pressure for detecting a pressure difference between a pressure near an inlet and a pressure near an outlet of the flow meter. A flow rate measuring method of a guess-type flow meter, comprising: a converting step of converting a pressure difference by the pressure measuring means into a flow rate value based on a conversion table; A flow rate change amount detecting step of detecting a change amount; a second determining step of determining whether a flow rate change amount in the flow rate change amount detecting step is equal to or more than a predetermined amount; and determining that the flow amount is equal to or more than a predetermined amount in the second determining step. Outputting the flow rate value obtained by the conversion step as a flow rate measurement result of the flow meter.
量を推測する流量計測手段と、当該流量計の流入口近傍
の圧力と流出口近傍の圧力との圧力差を検出する圧力計
測手段と、を備えた推量式流量計の流量計測方法におい
て、 前記圧力計測手段による圧力差を変換テーブルに基づき
流量値に変換する変換ステップと、 前記流量計測手段による流量計測結果が所定流量以下か
否かを判定する第1判定ステップと、 前記流量計測手段による流量計測結果に基づき流量の変
化量を検出する流量変化量検出ステップと、 前記流量変化量検出ステップによる流量の変化量が所定
量以上か否かを判定する第2判定ステップと、 前記第1判定ステップで所定流量以下と判定されたか、
または、前記第2判定ステップで所定量以上と判定され
たときに、前記変換ステップによって求められた流量値
を当該流量計の流量計測結果とする出力ステップと、 を有することを特徴とする流量計測方法。5. A flow rate measuring means for intermittently measuring a flow rate in a flow path to estimate an integrated flow rate, and a pressure for detecting a pressure difference between a pressure near an inlet and a pressure near an outlet of the flow meter. A flow rate measuring method for an inferential flow meter comprising: a converting step of converting a pressure difference by the pressure measuring means into a flow rate value based on a conversion table; and a flow rate measurement result by the flow rate measuring means being equal to or less than a predetermined flow rate. A first determining step of determining whether or not the flow rate is changed; a flow rate change detecting step of detecting a flow rate change based on a flow rate measurement result by the flow rate measuring means; A second determination step of determining whether or not the flow rate is equal to or more than whether the flow rate is determined to be equal to or less than a predetermined flow rate in the first determination step,
Or when the second determination step determines that the flow rate is equal to or greater than a predetermined amount, the flow step includes: using the flow rate value obtained by the conversion step as a flow rate measurement result of the flow meter. Method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP08422998A JP3383577B2 (en) | 1998-03-30 | 1998-03-30 | Ultrasonic flow meter and ultrasonic flow measurement method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP08422998A JP3383577B2 (en) | 1998-03-30 | 1998-03-30 | Ultrasonic flow meter and ultrasonic flow measurement method |
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Publication Number | Publication Date |
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JPH11281426A true JPH11281426A (en) | 1999-10-15 |
JP3383577B2 JP3383577B2 (en) | 2003-03-04 |
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JP08422998A Expired - Fee Related JP3383577B2 (en) | 1998-03-30 | 1998-03-30 | Ultrasonic flow meter and ultrasonic flow measurement method |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008102064A (en) * | 2006-10-20 | 2008-05-01 | Matsushita Electric Ind Co Ltd | Gas shut-off device |
JP2014190957A (en) * | 2013-03-28 | 2014-10-06 | Osaka Gas Co Ltd | Ultrasonic gas meter |
-
1998
- 1998-03-30 JP JP08422998A patent/JP3383577B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008102064A (en) * | 2006-10-20 | 2008-05-01 | Matsushita Electric Ind Co Ltd | Gas shut-off device |
JP2014190957A (en) * | 2013-03-28 | 2014-10-06 | Osaka Gas Co Ltd | Ultrasonic gas meter |
Also Published As
Publication number | Publication date |
---|---|
JP3383577B2 (en) | 2003-03-04 |
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