JP3888946B2

JP3888946B2 - Ultrasonic meter device

Info

Publication number: JP3888946B2
Application number: JP2002242177A
Authority: JP
Inventors: 泰宏藤井; 修一岡田; 滋田川; 秀樹山口; 幸雄木村; 龍雄藤本; 守鈴木; 克人酒井
Original assignee: Osaka Gas Co Ltd; Tokyo Gas Co Ltd; Toho Gas Co Ltd
Current assignee: Osaka Gas Co Ltd; Tokyo Gas Co Ltd; Toho Gas Co Ltd
Priority date: 2002-08-22
Filing date: 2002-08-22
Publication date: 2007-03-07
Anticipated expiration: 2022-08-22
Also published as: JP2004077445A

Description

【０００１】
【発明の属する技術分野】
本発明は、流体が流れる測定流路の上流側と下流側に一対の送受波器を設置し、前記測定流路を流れる流体の流れ方向に沿った順方向で超音波が前記送受波器間を伝播する順方向伝播時間と、前記順方向とは逆の逆方向で超音波が前記送受波器間を伝播する逆方向伝播時間とを計測する伝播時間計測手段と、前記伝播時間計測手段を働かせて計測した前記順方向伝播時間と前記逆方向伝播時間とから前記測定流路を流れる流体の流速に関する流速値を導出する測定手段を備えた超音波式メータ装置に関する。
【０００２】
【従来の技術】
従来、ガスメーターに使用されるメータ装置としては、膜式のものが主流であるが、その利便性等との関係から、今日、超音波を利用して流体の瞬時流速又は瞬時流量を測定する超音波式メータ装置の利用が提案されている。
【０００３】
かかる超音波式メータ装置は、流体が流通する測定流路の上流側と下流側に一対の送受波器を設置し、前記伝播時間計測手段により、流体の流れ方向に沿った順方向で超音波が前記送受波器間を伝播する順方向伝播時間ｔ１と、前記順方向とは逆の逆方向で超音波が前記送受波器間を伝播する逆方向伝播時間ｔ２とを計測する。このように計測した前記順方向伝播時間ｔ１と前記逆方向伝播時間ｔ２とは、測定流路の上記順方向に沿った流体の流速をｖとし、測定流路における流体中の音速をｃとし、送受波器間の距離をｄとしたときに、下記の数１に表すようになる。
【０００４】
【数１】
ｔ１＝ｄ／（ｃ＋ｖ）
ｔ２＝ｄ／（ｃ−ｖ）
【０００５】
従って、測定流路を流れる流体の流速ｖは、音速ｃに関係なく、下記の数２の式で求めることができる。
【０００６】
【数２】
ｖ＝（ｄ／２）・{（１／ｔ１）−（１／ｔ２）}
【０００７】
即ち、前記測定手段は、２秒間隔等の所定の測定時間間隔で、上記の数２の式により求められる流速、又は、その流速に測定流路の流路断面積を乗じて求められる流量を、流速に関する流速値として導出し、例えば、このように導出した測定時間間隔の流速値から、所定の使用期間内の使用流量等を求めることができる。
【０００８】
上記超音波式メータ装置において、前記伝播時間計測手段は、一方の送受波器に電気信号である入力信号を入力したときから、他方の送受波器で電気信号である出力信号を出力したときまでの到達時間から、一方の送受波器における入力信号を入力してから実際に音響信号である超音波を送信するまでの送信遅延時間と、他方の送受波器における音響信号である超音波を受信してから出力信号を出力するまでの受信遅延時間との和である遅延時間を差し引いた時間を、超音波が前記送受波器間を伝播する伝播時間として計測する。
【０００９】
そして、上記順方向及び上記逆方向夫々の遅延時間は、製造上の微妙な差異に起因して、相互間に差（以下、オフセットと呼ぶ。）が存在するため、上記の超音波式メータ装置は、その製造工程において、上記遅延時間の夫々を実測し、上記伝播時間計測手段で実際に計測した伝播時間から、上記実測した遅延時間を考慮して補正した伝播時間を用いて、流速又は流量を求めるように調整される。
【００１０】
【発明が解決しようとする課題】
しかし、上記超音波式メータ装置の使用過程において、上記送受波器の劣化等により、上記順方向及び上記逆方向夫々の遅延時間の差であるオフセットが変化することがあり、そのオフセットの経年的な変化により、正確な流速値の測定が行えなくなる場合がある。
【００１１】
また、このような超音波式メータ装置を用いるガスメータは、１ヶ月間等の継続的なガスの流通を認識した場合に、ガス漏洩が発生している可能性があるとして、遮断弁を働かせてガスを遮断するなどの漏洩検知機能を有する場合がある。
しかし、上記のように、上記オフセットが経年的に変化し、上記流速値の測定に測定誤差が発生した場合に、例えば、ガスが流通していないときでもガスが流通していると誤認してしまい、誤ってガスを遮断したり、逆に、ガスが漏洩しているにもかかわらず、ガスの流通を認識できずに、ガス漏洩を認識することができないことがある。
【００１２】
従って、本発明は、上記の事情に鑑みて、上記オフセットが経年的に変化しても、そのオフセットの変化に起因する測定誤差を簡単且つ正確に認識し、更に、正確に漏洩検知を実施することができる超音波式メータ装置を実現することを目的とする。
【００１３】
【課題を解決するための手段】
この目的を達成するための本発明に係る超音波式メータ装置の第一特徴構成は、特許請求の範囲の欄の請求項１に記載した如く、前記測定手段で導出された前記流速値から、所定の設定微小流速値未満に維持されている判定対象流速値を抽出する判定対象流速値抽出手段と、前記判定対象流速値抽出手段で抽出した前記判定対象流速値に対応する前記測定流路の圧力である判定対象圧力を導出する判定対象圧力導出手段と、複数の前記判定対象流速値と前記判定対象圧力とから、前記測定手段における測定誤差を判定する測定誤差判定手段とを備えた点にある。
【００１４】
前述の従来の技術の欄で説明したように、上記順方向及び上記逆方向夫々の遅延時間の差であるオフセットが経年的に変化すると、測定流路に流体が流通していない状態（以下、無流通状態と呼ぶ。）において測定手段で導出した流速値、所謂ゼロ点が、０を乖離した値にずれてしまう。そして、このようにゼロ点がずれてしまうと、前記測定手段で測定した流速値は、測定流路を流れる流体の実際の流速値を示すものでなくなり、実際の流速値に、測定手段におけるオフセットの経年変化に起因する測定誤差を加えた値となってしまう。
【００１５】
また、かかる超音波式メータ装置、特に、各家庭等に設けられたガスメータに用いる超音波メータ装置において、測定流路を流通する流体の流速値が非常に小さい上記微小流速値未満であるときには、測定流路に流体が流通していない無流通状態、若しくは、測定流路の下流側に接続されたガス機器の口火や漏洩等により、微小なガス等の流体がガバナ等による圧力調整を受けずに消費又は流出されている微小流通状態であると判断できる。
【００１６】
また、上記微小流通状態における実際の流速値は、流体の流出部の面積に比例すると共に、測定流路の圧力、即ち流体の圧力の平方根に比例した値となり、更に、微小流通状態における上記流出部の面積がほぼ一定であるとすると、微小流通状態における実際の流速値は、圧力の平方根に比例した値となる。
【００１７】
従って、上記のように無流通状態又は微小流通状態において測定手段で導出した流速値は、上記圧力の平方根に比例する項（但し、無流通状態では比例係数は０となる。）と測定誤差の定数項とを加算した式で表すことができる。
【００１８】
そこで、上記第一特徴構成の超音波式メータ装置によれば、前記判定対象流速値抽出手段により、前記測定流路の流体の流速値が極めて小さい設定微小流速値未満に維持され、無流通状態又は微小流通状態であると認識した複数の時点において前記測定手段で導出された夫々の流速値を判定対象流速値として抽出すると共に、圧力センサ等からなる判定対象圧力導出手段により、前記判定対象流速値抽出手段により抽出した夫々の判定対象流速値に対応する測定流路の圧力を前記判定対象圧力として夫々導出することができる。
【００１９】
そして、前記測定誤差判定手段により、無流通状態又は微小流通状態において測定手段で導出した流速値が、圧力の平方根に比例する項と測定誤差の定数項とを加算した式で表せることから、上記のように得た無流通状態又は微小流通状態における複数の前記判定対象流速値と前記判定対象圧力とから、その流速値を表す式における定数項である測定誤差を算出して、測定誤差の発生又はその程度を判定することができる。
【００２０】
従って、上記オフセットが経年的に変化しても、そのオフセットの変化に起因する測定誤差を簡単且つ正確に認識することができる超音波式メータ装置を実現することができる。
【００２１】
本発明に係る超音波式メータ装置の第二特徴構成は、特許請求の範囲の欄の請求項２に記載した如く、上記第一特徴構成に加えて、前記測定手段が、所定の設定時間内に所定の測定時間間隔で前記伝播時間計測手段を働かせて導出した瞬時流速値の平均値を前記流速値として導出するように構成されている点にある。
【００２２】
測定流路の流速値は、流体の圧力変動等により、比較的高周波のノイズが付加された不安定な状態となることがあり、このような流速値から、上記異常状態判定のために用いる判定対象流速値を抽出すると、上記のノイズによる瞬時値の変動により、前記測定誤差を誤判定することが懸念される。
【００２３】
そこで、上記第二特徴構成の超音波式メータ装置によれば、前記測定手段により、例えば２秒間隔等の前記測定時間間隔で前伝播時間計測手段を働かせて測定流路を流れる流体の瞬時流速又は瞬時流量を示す瞬時流速値を導出すると共に、３０秒等の前記設定時間毎に、その設定時間内に導出した瞬時流速値の平均値を流速値として導出することで、このように導出した流速値は、上記高周波のノイズを相殺した比較的安定したものとなる。よって、前記測定誤差判定手段において、このように安定した流速値である判定対象流速値を用いて、上記誤判定を回避して精度良く前記測定誤差を判定することができる。
【００２４】
本発明に係る超音波式メータ装置の第三特徴構成は、特許請求の範囲の欄の請求項３に記載した如く、上記第二特徴構成に加えて、前記測定手段が、前記流速値と共に、前記複数の瞬時流速値の最大値及び最小値を導出するように構成され、前記判定対象流速値抽出手段が、前記測定手段で導出した前記流速値が前記微小流速値未満であり、且つ、前記測定手段で導出した前記最大値と前記最小値との差である流速値変化量が所定の設定流速値変化量未満である場合に、前記流速値を前記判定対象流速値として抽出するように構成されている点にある。
【００２５】
上記第三特徴構成の超音波式メータ装置によれば、前記判定対象流速値抽出手段により、前記測定手段で導出した前記流速値が、前記測定流路の下流側に接続された消費機器の運転時に消費される流体の最小流量以下の下限界設定流量に相当する設定流速値未満であり、且つ、その流速値に対応して前記測定手段で導出した各設定時間内の瞬時流速値の最大値と最小値との差、即ち、設定時間内における瞬時流速値の流速値変化量が、非常に小さい設定流速値変化量未満である場合に、無流通状態又は微小流通状態であると判断でき、その流速値を所定の微小流速値未満に維持されている前記判定対象流速値として抽出することができる。
【００２６】
【発明の実施の形態】
本発明に係る超音波式メータ装置の実施の形態について、図面に基づいて説明する。
図１には、本実施形態の超音波式メータ装置１（以下、本発明装置１と略称する。）により測定流路２を流れるガスｆの流量測定を実施している状況が示されている。
流量測定対象流体であるガスｆは、導入部３から測定流路２に流入し、導出部４より排出される。即ち、同図において、測定流路２でのガスｆの流れ方向は、左から右に向かう方向である。
【００２７】
本発明装置１は、測定流路２の上流側と下流側とに設置される一対の送受波器５と、この送受波器５に接続される制御装置１０とから構成されている
【００２８】
測定流路２の上流側に設置された送受波器５ａと、測定流路２の下流側に設置された送受波器５ｂとは、距離ｄを隔てた位置に互いに対向して設置され、その対向方向と測定流路２を流通するガスｆの流れ方向とが角度θをなす。
【００２９】
また、この送受波器５は、制御装置１０から電気信号である入力信号が入力されると音響信号である超音波を他方の送受波器５側に向けて送信し、更に、他方の送受波器５側から送信された超音波を受信すると、電気信号である出力信号を制御装置１０に出力するように構成されている。
【００３０】
制御装置１０は、タイマ１７、メモリ又はハードディスク等からなる記憶部１８、液晶表示部等からなる出力部１９等を備えたコンピュータで構成されており、そのコンピュータが所定のプログラムを実行することにより、後述の伝播時間計測手段１１、測定手段１２、判定対象流速値抽出手段１３、判定対象圧力導出手段１４、測定誤差判定手段１５、漏洩判定手段１６等の様々な手段として機能する。
【００３１】
制御装置１０が機能する伝播時間計測手段１１は、上流側の送受波器５ａに入力信号を入力してから下流側の送受波器５ｂで出力信号が出力されるまでの時間から順方向の遅延時間を差し引いた時間を、測定流路２を流れるガスｆの流れ方向に沿った順方向で超音波が送受波器５間を伝播する順方向伝播時間ｔ１として計測すると共に、下流側の送受波器５ｂに入力信号を入力してから上流側の送受波器５ａで出力信号が出力されるまでの時間からから逆方向の遅延時間を差し引いた時間を、前記順方向とは逆の逆方向で超音波が送受波器５間を伝播する逆方向伝播時間ｔ２として計測するように構成されている。
尚、上記順方向及び逆方向の遅延時間とは、順方向及び逆方向の夫々において、一方の送受波器における入力信号を入力してから実際に音響信号である超音波を送信するまでの送信遅延時間と、他方の送受波器における音響信号である超音波を受信してから出力信号を出力するまでの受信遅延時間との和であり、これら遅延時間は、本発明装置１の製造時に計測されたものである。
【００３２】
また、伝播時間計測手段１１は、図２の処理フロー図に示すように、タイマ１７を用いて、このような順方向伝播時間ｔ１と逆方向伝播時間ｔ２との計測を、２秒間隔（測定時間間隔の一例）で実行する（＃１０１）。
また、制御装置１０が機能する測定手段１２は、伝播時間計測手段１１により計測され記憶部１８に格納された順方向伝播時間ｔ１と逆方向伝播時間ｔ２とから、下記の数３の式を用いて、測定流路２を流れるガスｆの瞬時流速ｖを求め、その瞬時流速ｖ自身又はその瞬時流速ｖに測定流路２の断面積を乗じて求めた瞬時流量を瞬時流速値ｑとして導出する（＃１０２）。
そして、上記伝播時間計測手段１１で計測された順方向伝播時間ｔ１及び方向伝播時間ｔ２、上記測定手段１２で導出された瞬時流速値ｑは、２秒間隔で記憶部１８に格納される。
【００３３】
【数３】
ｖ＝ｖ’／ｃｏｓθ＝（ｄ／２ｃｏｓθ）・{（１／ｔ１）−（１／ｔ２）}
【００３４】
更に、測定流路２には、測定流路２の圧力を計測可能な圧力センサ７が設けられており、制御装置１０は、２秒間隔で圧力センサ７を働かせて、測定流路２の圧力ｐを検出し、記憶部１８に格納する（＃１０３）。
【００３５】
また、制御装置１０は、図３の処理フロー図に示すように、３０秒（設定時間の一例）毎に、その３０秒間内に２秒間隔で導出した１５個の上記瞬時流速値ｑの平均値を流速値ｑ_ａｖｅとして導出し、更に、その３０秒間内の複数の瞬時流速値ｑの中から、最大値ｑ_ｍａｘと最小値ｑ_ｍｉｎとを抽出すると共に、その３０秒間内に２秒間隔で導出した１５個の上記圧力ｐの平均値を平均圧力ｐ_ａｖｅとして導出し、更に、その３０秒間内の複数の圧力ｐの中から、最大値ｐ_ｍａｘと最小値ｐ_ｍｉｎとを抽出する（＃２０１）。
【００３６】
次に、制御装置１０が機能する判定対象流速値抽出手段１３は、測定手段１２で導出した流速値ｑ_ａｖｅが所定の範囲内に安定状態に維持されているか否かを判定し、安定状態であると判定したときに、その流速値ｑ_ａｖｅを判定対象流速値Ｑとして抽出する。
即ち、判定対象流速値抽出手段１３は、先ず、測定手段１２で３０秒毎に導出される流速値ｑ_ａｖｅが、６０Ｌ／ｈ程度に相当する設定微小流速値Ａ未満の範囲内である安定状態であるかを判定する（＃２０２）。
尚、上記設定微小流速値Ａは、測定流路２の下流側に接続されたガス機器の口火や漏洩等によりガスが消費又は流出している状態、所謂微小流通状態であると判断できる最大流速値に相当する。
【００３７】
更に、判定対象流速値抽出手段１３は、上記流速値ｑ_ａｖｅが設定微小流速値Ａ未満であると判定したときには、測定手段１２で導出した最大値ｑ_ｍａｘと最小値ｑ_ｍｉｎとの差である流速値変化量が、非常に小さい１．５Ｌ／ｈ等に相当する所定の設定流速値変化量Ｂ未満であるかを判定する（＃２０３）。
【００３８】
そして、判定対象流速値抽出手段１３は、上記流速値ｑ_ａｖｅが上記設定微小流速値Ａ未満であり、且つ、上記流速値変化量が所定の設定流速値変化量Ｂ未満である状態を、その３０秒内において常にガス機器の運転が停止されており測定流路２のガスｆの瞬時流速値ｑが常に０近傍に維持されている無流通状態、又は、微小なガスｆがガス機器の口火や漏洩等により消費又は流出しており測定流路２のガスｆの瞬時流速値ｑが３〜６０Ｌ／ｈ程度に相当する値に維持されている微小流通状態であると判定し、そのときの流速値ｑ_ａｖｅを判定対象流速値Ｑとして抽出する（＃２０４）。
【００３９】
また、このようにして抽出した判定対象流速値Ｑは、前述の如く、無流通状態又は微小流通状態において測定手段１２で導出された流速値であるので、圧力の平方根に比例する実際の流速値に、測定手段１２における上記順方向の遅延時間と上記逆方向遅延時間との差であるオフセットの経年変化に起因する測定誤差を加算した値となる。
即ち、測定流路１２の圧力をｐ、圧力の平方根に対する比例係数をα、測定誤差をβとすると、判定対象流速値Ｑは、下記の数4に示すような式で表すことができる。
【００４０】
【数４】

【００４１】
制御装置１０が機能する判定対象圧力導出手段１４は、上記のように判定対象流速値抽出手段１３で流速値ｑ_ａｖｅを判定対象流速値Ｑとして抽出するに、測定流路２の平均圧力ｐ_ａｖｅが、短い周期で発生するガスｆの圧力変動の影響を受けていない信頼できる圧力であるかを判定する。即ち、判定対象圧力抽出手段１４は、圧力ｐの最大値ｐ_ｍａｘと最小値ｐ_ｍｉｎとの差である圧力変化量が、２０Ｐａ程度の所定の設定圧力変化量Ｃ未満であるかを判定する（＃２０５）。
そして、圧力変化量が設定圧力変化量Ｃ未満であった場合に、そのときの平均圧力ｐ_ａｖｅを上記判定対象流速値Ｑに対する判定対象圧力Ｐとして抽出する（＃２０６）。
【００４２】
尚、判定対象流速値Ｑ及び判定対象圧力Ｐを抽出するに、流速値ｑ_ａｖｅが上記設定微小流速値Ａ未満であり、且つ、上記流速値変化量が所定の設定流速値変化量Ｂ未満であり、且つ、上記圧力変化量が所定の設定圧力変化量Ｃ未満であるときに、再度、記測定時間間隔よりも短い周期、例えば、５秒間に１００ｍ秒間隔で測定手段１２及び圧力センサ７を働かせて、例えば、上、瞬時流速値及び圧力を計測し、その瞬時流速値及び圧力の平均値を、判定対象流速値Ｑ及び判定対象圧力Ｐとして抽出しても構わない。
【００４３】
更に、制御装置１０は、詳細については後述するが、測定誤差判定手段１５により、上記判定対象流速値Ｑと上記判定対象圧力Ｐとの判定対象データ（Ｑ，Ｐ）を、記憶部１８に格納すると共に、その判定対象データ（Ｑ，Ｐ）を用いて測定誤差を判定するための測定誤差判定処理、及び、漏洩状態を判定するための漏洩判定処理等を実行する。
【００４４】
即ち、制御装置１０が機能する測定誤差判定手段１５は、前述のように、無流通状態又は微小流通状態において測定手段１２で導出された流速値である判定対象流速値Ｑが、判定対象圧力Ｐの平方根に比例する項と測定誤差βの定数項とを加算した式で表せることから、複数の判定対象データ（Ｑ，Ｐ）から、測定誤差βを算出して、測定誤差の発生又はその程度を判定することができ、その測定誤差判定処理の処理フローを、図４に基づいて説明する。
【００４５】
先ず、測定誤差判定手段１５は、判定対象流速値抽出手段１３及び判定対象圧力導出手段１４で判定対象データ（Ｑ，Ｐ）が導出されると、その判定対象データ（Ｑ，Ｐ）を順に取得する（＃３０１）。
【００４６】
また、測定誤差判定手段１５は、１日又は１ヶ月等の判定期間の最初に導出された判定対象データ（Ｑ，Ｐ）を、第一判定対象データ（Ｑ（１），Ｐ（１））として取得する（＃３０２）。
【００４７】
また、第一判定対象データ（Ｑ（１），Ｐ（１））を取得した後に、判定対象圧力Ｐが上記第一判定対象データ（Ｑ（１），Ｐ（１））における圧力Ｐ（１）に対する圧力変化率が０．１等の所定の設定圧力変化率Ｄ以上であるかを判定し（＃３０３）、上記圧力変化率が０．１以上であった場合には、そのときの判定対象データ（Ｑ，Ｐ）を、第二判定対象データ（Ｑ（２），Ｐ（２））として取得する（＃３０４）。
【００４８】
一方、上記圧力変化率が設定圧力変化率Ｄ未満である場合には、そのときの判定対象データ（Ｑ，Ｐ）と、上記第一判定対象データ（Ｑ（１），Ｐ（１））との夫々が、圧力Ｐが十分に異なるデータでないため、その両データを用いて、流速値と圧力との相関を正確に求めることができないとして、その判定対象データ（Ｑ，Ｐ）を第二判定対象データ（Ｑ（２），Ｐ（２））とせずに、次の判定対象データ（Ｑ，Ｐ）を取得する。
【００４９】
尚、上記圧力変化率が所定の設定圧力変化率Ｄ以上であった場合に、第二判定対象データ（Ｑ（２），Ｐ（２））を取得したが、別に、判定対象流速値Ｑが上記第一判定対象データ（Ｑ（１），Ｐ（１））における流速値Ｑ（１）に対する流速値変化率が所定の設定流速値変化率以上である場合に、第二判定対象データ（Ｑ（２），Ｐ（２））を取得しても構わない。
【００５０】
そして、測定誤差判定手段１５は、このように取得した第一判定対象データ（Ｑ（１），Ｐ（１））と第二判定対象データ（Ｑ（２），Ｐ（２））とを前述の数４の式に代入することにより導き出される連立方程式を解いて、測定手段１２における測定誤差βを算出し（＃３０５）、その測定誤差βの絶対値が所定の設定測定誤差Ｅ以上であれば、測定手段１２において無視できない程度の測定誤差が発生しているとして、例えば、出力部１９に測定誤差発生の旨を出力するなどして、測定誤差発生の通報処理を行う（＃３０７）。
【００５１】
尚、上記測定誤差βの絶対値の大きさにより、測定誤差の程度を大・中・小等の複数の段階で判定し、その測定誤差の程度をも通報するように構成しても構わない。例えば、判定誤差βが５Ｌ／ｈ以上であれば、致命的な判定誤差が発生したとして、上記通報処理を行うと共にガスｆの流通を遮断し、判定誤差βが５Ｌ／ｈ未満且つ１．５Ｌ／ｈ以上であれば上記通報処理のみを行い、判定誤差βが１．５Ｌ／ｈ未満であれば判定誤差は発生していないとして、データをリセットして、再度測定誤差判定処理を実行することができる。
【００５２】
また、測定誤差βの絶対値が所定の設定測定誤差Ｅ以上となってすぐに測定誤差発生の通報処理等を行うのではなく、複数回にわたって測定誤差βの絶対値が所定の設定測定誤差Ｅ以上となったときに、測定誤差発生の通報処理等を行っても構わない。
【００５３】
また、第一判定対象データ（Ｑ（１），Ｐ（１））と第二判定対象データ（Ｑ（２），Ｐ（２））とがある程度近い時期に導出したデータであるほうが、測定誤差を正確に判定することができるので、測定誤差判定処理は、例えば、１ヶ月等の判定期間毎に、上記両データを全て０にリセットして繰り返し行うほうが好ましい。
【００５４】
また、上記測定誤差判定処理において、測定誤差βの絶対値が所定の設定測定誤差Ｅ未満となり、測定誤差が発生してないと判定したときには、例えば、３０日等の所定の期間が経過後に、再度測定誤差判定処理を実施するように制御装置１０を構成しても構わない。
【００５５】
また、制御装置１０が機能する漏洩判定手段１６は、測定流路２においてガスｆが例えば１ヶ月等の所定の設定期間継続して流通している場合に、漏洩状態と判定する漏洩判定処理を実行し、その構成について、図５の処理フローに基づいて説明する。
【００５６】
即ち、経過時間ｔを０にリセットして（＃４０１）、３０秒毎に導出される上記の判定対象流速値Ｑを取得し（＃４０２）、その判定対象流速値Ｑから上記の測定誤差判定処理で導出した測定誤差βを差し引いた値が所定の設定判定値Ｆ以上であるかを判定する（＃４０３）。
そして、最初にその判定対象流速値Ｑから上記測定誤差βを差し引いた値が所定の設定判定値Ｆ以上となったときからの経過時間ｔが、１ヶ月等の所定の設定期間Ｇに達したことを判定して（＃４０４）、経過時間ｔが所定の設定期間Ｇに達したと判定した場合には、ガスｆが例えば１ヶ月等の所定の設定期間継続して流通していると判断し、所定の漏洩通報処理と共に、ガスｆの流通を遮断する遮断処理を行うことができる。
【図面の簡単な説明】
【図１】超音波式メータ装置により流速値測定を実施している状況を示す図
【図２】伝播時間計測及び瞬時流速値導出処理及び圧力導出処理を示す処理フロー図
【図３】判定対象流速値及び判定対象圧力導出処理を示す処理フロー図
【図４】測定誤差判定処理を示す処理フロー図
【図５】漏洩判定処理を示す処理フロー図
【符号の説明】
１：超音波式メータ装置（本発明装置）
２：測定流路
５：送受波器
１０４：制御装置
１１：伝播時間計測手段
１２：測定手段
１３：判定対象流速値抽出手段
１４：判定対象圧力導出手段
１５：測定誤差判定手段
１６：漏洩判定手段
１８：記憶部
ｆ：ガス（流体）[0001]
BACKGROUND OF THE INVENTION
In the present invention, a pair of transducers are installed on the upstream side and the downstream side of a measurement channel through which fluid flows, and ultrasonic waves are transmitted between the transducers in the forward direction along the flow direction of the fluid flowing through the measurement channel. Propagation time measuring means for measuring a forward propagation time for propagating in the reverse direction and a backward propagation time for ultrasonic waves to propagate between the transducers in a direction opposite to the forward direction, and the propagation time measuring means The present invention relates to an ultrasonic meter device provided with a measuring means for deriving a flow velocity value related to the flow velocity of the fluid flowing through the measurement flow path from the forward propagation time and the backward propagation time measured by working.
[0002]
[Prior art]
Conventionally, as a meter device used for a gas meter, a membrane type is mainly used. However, due to its convenience and the like, today, an ultrasonic flow rate or instantaneous flow rate of a fluid is measured using ultrasonic waves. The use of a sonic meter device has been proposed.
[0003]
Such an ultrasonic meter device is provided with a pair of transducers on the upstream side and the downstream side of a measurement channel through which a fluid flows, and ultrasonic waves are transmitted in the forward direction along the fluid flow direction by the propagation time measuring means. Measures the forward propagation time t1 for propagation between the transducers and the backward propagation time t2 for the ultrasonic wave to propagate between the transducers in the opposite direction to the forward direction. The forward propagation time t1 and the backward propagation time t2 measured in this way are v, the flow velocity of the fluid along the forward direction of the measurement channel, and c the velocity of sound in the fluid in the measurement channel, When the distance between the transmitter and the receiver is d, the following equation 1 is obtained.
[0004]
[Expression 1]
t1 = d / (c + v)
t2 = d / (cv)
[0005]
Therefore, the flow velocity v of the fluid flowing through the measurement channel can be obtained by the following equation 2 regardless of the sound velocity c.
[0006]
[Expression 2]
v = (d / 2) · {(1 / t1) − (1 / t2)}
[0007]
In other words, the measuring means has a flow rate obtained by the above equation (2) or a flow rate obtained by multiplying the flow rate by the cross-sectional area of the measurement flow channel at a predetermined measurement time interval such as a 2-second interval. For example, the flow rate value within a predetermined use period can be obtained from the flow rate value of the measurement time interval derived as described above.
[0008]
In the ultrasonic meter device, the propagation time measuring means is from when an input signal that is an electrical signal is input to one transducer, to when an output signal that is an electrical signal is output from the other transducer. From the arrival time of, the transmission delay time from the input of the input signal in one transducer to the actual transmission of the ultrasonic wave as the acoustic signal and the ultrasonic wave as the acoustic signal in the other transducer Then, the time obtained by subtracting the delay time that is the sum of the reception delay time until the output signal is output is measured as the propagation time for the ultrasonic wave to propagate between the transducers.
[0009]
Since the delay times in the forward direction and the backward direction are different from each other (hereinafter referred to as offset) due to slight differences in manufacturing, the ultrasonic meter device described above. In the manufacturing process, each of the delay times is actually measured, and the flow time or flow rate is calculated using the propagation time corrected in consideration of the actually measured delay time from the propagation time actually measured by the propagation time measuring means. It is adjusted to ask for.
[0010]
[Problems to be solved by the invention]
However, in the process of using the ultrasonic meter device, the offset, which is the difference between the delay times in the forward direction and the reverse direction, may change due to deterioration of the transducer, etc. Depending on the change, accurate measurement of the flow velocity value may not be possible.
[0011]
In addition, a gas meter using such an ultrasonic meter device has a function of a shut-off valve that may cause gas leakage when recognizing continuous gas flow for one month or the like. It may have a leak detection function such as shutting off gas.
However, as described above, when the offset changes over time and a measurement error occurs in the measurement of the flow velocity value, for example, it is mistaken that the gas is flowing even when the gas is not flowing. Therefore, there is a case where the gas leakage cannot be recognized without being able to recognize the circulation of the gas even though the gas is accidentally shut off or, conversely, the gas is leaking.
[0012]
Therefore, in view of the above circumstances, the present invention easily and accurately recognizes a measurement error caused by a change in the offset even when the offset changes with time, and further accurately performs leak detection. An object of the present invention is to realize an ultrasonic meter device that can be used.
[0013]
[Means for Solving the Problems]
In order to achieve this object, the first characteristic configuration of the ultrasonic meter device according to the present invention is, as described in claim 1 of the claims, from the flow velocity value derived by the measuring means, A determination target flow velocity value extracting means for extracting a determination target flow velocity value maintained below a predetermined set minute flow velocity value, and a measurement flow path corresponding to the determination target flow velocity value extracted by the determination target flow velocity value extraction means; A determination target pressure deriving unit that derives a determination target pressure that is a pressure, and a measurement error determination unit that determines a measurement error in the measurement unit from a plurality of the determination target flow velocity values and the determination target pressure. is there.
[0014]
As described above in the section of the prior art, when the offset, which is the difference between the delay times in the forward direction and the reverse direction, changes with time, a state in which no fluid flows in the measurement channel (hereinafter, In this case, the flow velocity value derived by the measuring means, that is, the so-called zero point, shifts to a value that deviates from 0. If the zero point is deviated in this way, the flow velocity value measured by the measurement means does not indicate the actual flow velocity value of the fluid flowing through the measurement flow path, and the actual flow velocity value is offset by the measurement means. It becomes the value which added the measurement error resulting from the secular change.
[0015]
In addition, in such an ultrasonic meter device, particularly an ultrasonic meter device used in a gas meter provided in each home, etc., when the flow velocity value of the fluid flowing through the measurement channel is less than the very small flow velocity value, The fluid such as minute gas is not subject to pressure adjustment by the governor due to the non-flowing state where the fluid does not flow through the measurement channel, or the fire or leakage of gas equipment connected to the downstream side of the measurement channel. It can be determined that the micro-distributed state is consumed or discharged.
[0016]
The actual flow velocity value in the minute flow state is proportional to the area of the outflow portion of the fluid and is also proportional to the pressure of the measurement channel, that is, the square root of the pressure of the fluid. Assuming that the area of the part is substantially constant, the actual flow velocity value in the minute flow state is a value proportional to the square root of the pressure.
[0017]
Therefore, the flow velocity value derived by the measuring means in the non-flowing state or the micro-flowing state as described above is a term proportional to the square root of the pressure (however, the proportionality coefficient is 0 in the non-flowing state) and the measurement error. It can be expressed by an expression obtained by adding a constant term.
[0018]
Therefore, according to the ultrasonic meter device of the first characteristic configuration, the flow velocity value extraction means for determination determines that the flow velocity value of the fluid in the measurement flow path is kept below a very small set minute flow velocity value, and is in a non-flowing state. Alternatively, each of the flow velocity values derived by the measuring unit at a plurality of time points recognized as being in a minute flow state is extracted as a determination target flow velocity value, and the determination target pressure deriving unit including a pressure sensor is used to determine the determination target flow velocity. The pressure in the measurement channel corresponding to each determination target flow velocity value extracted by the value extraction unit can be derived as the determination target pressure.
[0019]
And, by the measurement error determination means, the flow velocity value derived by the measurement means in the non-flowing state or in the minute flow state can be expressed by an expression in which a term proportional to the square root of the pressure and a constant term of the measurement error are added. The measurement error, which is a constant term in the equation representing the flow velocity value, is calculated from the plurality of flow velocity values to be judged and the pressure to be judged in the non-flowing state or the minute flow state obtained as described above. Alternatively, the degree can be determined.
[0020]
Accordingly, it is possible to realize an ultrasonic meter device that can easily and accurately recognize a measurement error caused by a change in the offset even if the offset changes with time.
[0021]
The second characteristic configuration of the ultrasonic meter device according to the present invention is that, in addition to the first characteristic configuration, the measuring means is within a predetermined set time as described in claim 2 in the claims. The average value of the instantaneous flow velocity values derived by operating the propagation time measuring means at predetermined measurement time intervals is derived as the flow velocity value.
[0022]
The flow velocity value of the measurement channel may be in an unstable state to which relatively high-frequency noise is added due to fluid pressure fluctuation, etc., and the determination used for the abnormal state determination from such a flow velocity value. When the target flow velocity value is extracted, there is a concern that the measurement error may be erroneously determined due to the fluctuation of the instantaneous value due to the noise.
[0023]
Therefore, according to the ultrasonic meter device having the second characteristic configuration, the instantaneous flow velocity of the fluid flowing through the measurement flow path by using the measurement means by using the pre-propagation time measurement means at the measurement time interval such as an interval of 2 seconds. Alternatively, the instantaneous flow velocity value indicating the instantaneous flow rate is derived, and at each set time such as 30 seconds, the average value of the instantaneous flow velocity values derived within the set time is derived as the flow velocity value. The flow velocity value is relatively stable with the high frequency noise cancelled. Therefore, the measurement error determination means can accurately determine the measurement error by avoiding the erroneous determination using the determination target flow velocity value that is a stable flow velocity value.
[0024]
The third characteristic configuration of the ultrasonic meter device according to the present invention is, in addition to the second characteristic configuration described above, in addition to the second characteristic configuration, the measurement means includes the flow velocity value as described in claim 3 of the claims. It is configured to derive a maximum value and a minimum value of the plurality of instantaneous flow velocity values, and the determination target flow velocity value extraction unit is configured such that the flow velocity value derived by the measurement unit is less than the minute flow velocity value, and The flow rate value is extracted as the determination target flow rate value when the flow rate value change amount, which is the difference between the maximum value and the minimum value derived by the measuring means, is less than a predetermined set flow rate value change amount. It is in the point.
[0025]
According to the ultrasonic meter device having the third characteristic configuration, the flow rate value derived by the measurement unit is operated by the determination target flow rate value extraction unit, and the operation of the consumer device connected to the downstream side of the measurement channel is performed. The maximum value of the instantaneous flow velocity value within each set time that is less than the set flow rate value corresponding to the lower limit set flow rate that is less than or equal to the minimum flow rate of the fluid that is sometimes consumed and that is derived by the measuring means corresponding to the flow rate value And the minimum value, that is, when the change in the flow velocity value of the instantaneous flow velocity value within the set time is less than the very small set flow velocity value change amount, it can be determined that there is no flow state or a minute flow state, The flow velocity value can be extracted as the determination target flow velocity value maintained below a predetermined minute flow velocity value.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of an ultrasonic meter device according to the present invention will be described with reference to the drawings.
FIG. 1 shows a situation in which the flow rate measurement of the gas f flowing through the measurement flow path 2 is performed by the ultrasonic meter device 1 of the present embodiment (hereinafter simply referred to as the device 1 of the present invention). .
A gas f that is a flow rate measurement target fluid flows into the measurement channel 2 from the introduction unit 3 and is discharged from the derivation unit 4. That is, in the same figure, the flow direction of the gas f in the measurement flow path 2 is a direction from left to right.
[0027]
The device 1 of the present invention includes a pair of transducers 5 installed on the upstream side and the downstream side of the measurement channel 2 and a control device 10 connected to the transducers 5.
The transducer 5a installed on the upstream side of the measurement channel 2 and the transducer 5b installed on the downstream side of the measurement channel 2 are installed facing each other at a position separated by a distance d. The facing direction and the flow direction of the gas f flowing through the measurement channel 2 form an angle θ.
[0029]
In addition, when an input signal, which is an electrical signal, is input from the control device 10, the transducer 5 transmits an ultrasonic wave, which is an acoustic signal, toward the other transducer 5 side, and further, the other transducer is received. When an ultrasonic wave transmitted from the device 5 side is received, an output signal that is an electric signal is output to the control device 10.
[0030]
The control device 10 is configured by a computer including a timer 17, a storage unit 18 including a memory or a hard disk, an output unit 19 including a liquid crystal display unit, and the like, and when the computer executes a predetermined program, It functions as various means such as a propagation time measurement means 11, a measurement means 12, a determination target flow velocity value extraction means 13, a determination target pressure derivation means 14, a measurement error determination means 15, and a leakage determination means 16 which will be described later.
[0031]
The propagation time measuring means 11 in which the control device 10 functions is a forward delay from the time from when the input signal is input to the upstream transducer 5a to when the output signal is output from the downstream transducer 5b. The time obtained by subtracting the time is measured as a forward propagation time t1 in which the ultrasonic wave propagates between the transducers 5 in the forward direction along the flow direction of the gas f flowing through the measurement flow path 2, and the downstream transmission / reception wave The time obtained by subtracting the reverse delay time from the time from when the input signal is input to the transmitter 5b until the output signal is output at the upstream transducer 5a is the reverse direction opposite to the forward direction. The ultrasonic wave is configured to be measured as a backward propagation time t <b> 2 for propagating between the transducers 5.
Note that the forward and reverse delay times are the transmissions from the input of the input signal in one transducer in the forward and reverse directions to the actual transmission of the ultrasonic wave as an acoustic signal. It is the sum of the delay time and the reception delay time from the reception of the ultrasonic wave, which is an acoustic signal in the other transducer, to the output of the output signal. These delay times are measured when the device 1 of the present invention is manufactured. It has been done.
[0032]
Further, as shown in the process flow diagram of FIG. 2, the propagation time measuring means 11 uses the timer 17 to measure such forward propagation time t1 and backward propagation time t2 at intervals of 2 seconds (measurement). (Example of time interval) is executed (# 101).
Further, the measuring unit 12 in which the control device 10 functions uses the following formula 3 from the forward propagation time t1 and the backward propagation time t2 measured by the propagation time measuring unit 11 and stored in the storage unit 18. Thus, the instantaneous flow velocity v of the gas f flowing through the measurement flow path 2 is obtained, and the instantaneous flow velocity v itself or the instantaneous flow velocity v obtained by multiplying the cross-sectional area of the measurement flow path 2 is derived as the instantaneous flow velocity value q. (# 102).
Then, the forward propagation time t1 and the direction propagation time t2 measured by the propagation time measuring means 11 and the instantaneous flow velocity value q derived by the measuring means 12 are stored in the storage unit 18 at intervals of 2 seconds.
[0033]
[Equation 3]
v = v ′ / cos θ = (d / 2 cos θ) · {(1 / t1) − (1 / t2)}
[0034]
Further, the measurement channel 2 is provided with a pressure sensor 7 capable of measuring the pressure in the measurement channel 2, and the control device 10 operates the pressure sensor 7 at intervals of 2 seconds to p is detected and stored in the storage unit 18 (# 103).
[0035]
Further, as shown in the processing flow diagram of FIG. 3, the control device 10 calculates the average of the 15 instantaneous flow velocity values q derived every 2 seconds within 30 seconds every 30 seconds (an example of the set time). A value is derived as a flow velocity value q _ave , and a maximum value q _max and a minimum value q _min are extracted from a plurality of instantaneous flow velocity values q within the 30 seconds, and at intervals of 2 seconds within the 30 seconds. The average value of the fifteen pressures p derived in the above is derived as an average pressure p _ave , and a maximum value p _max and a minimum value p _min are extracted from a plurality of pressures p within 30 seconds ( # 201).
[0036]
Next, the determination target flow velocity value extraction unit 13 that the control device 10 functions determines whether or not the flow velocity value q _ave derived by the measurement unit 12 is maintained in a stable state within a predetermined range. When it is determined that there is, the flow velocity value q _ave is extracted as the determination target flow velocity value Q.
That is, the determination target flow velocity value extracting means 13 first has a stable state in which the flow velocity value q _ave derived every 30 seconds by the measuring means 12 is within a range less than the set minute flow velocity value A corresponding to about 60 L / h. Is determined (# 202).
The set micro flow velocity value A is the maximum flow velocity at which it is possible to determine that the gas is consumed or flowing out due to a gas appliance connected to the downstream side of the measurement flow channel 2 or leaked, that is, a so-called micro flow state. Corresponds to the value.
[0037]
Further, when the determination target flow velocity value extraction means 13 determines that the flow velocity value q _ave is less than the set minute flow velocity value A, it is the difference between the maximum value q _max and the minimum value q _min derived by the measurement means 12. It is determined whether the flow rate value change amount is less than a predetermined set flow rate value change amount B corresponding to a very small value of 1.5 L / h (# 203).
[0038]
Then, the determination target flow velocity value extraction unit 13 determines that the flow velocity value q _ave is less than the set minute flow velocity value A and the flow velocity value change amount is less than a predetermined set flow velocity value change amount B. The operation of the gas device is always stopped within 30 seconds, and the instantaneous flow velocity value q of the gas f in the measurement channel 2 is always maintained near 0, or the minute gas f is ignited by the gas device. It is determined that the flow rate q of the gas f in the measurement flow path 2 is consumed or discharged due to leakage or the like and is maintained at a value corresponding to about 3 to 60 L / h. The flow velocity value q _ave is extracted as the determination target flow velocity value Q (# 204).
[0039]
Further, since the determination target flow velocity value Q extracted in this way is a flow velocity value derived by the measuring means 12 in the non-flowing state or the minute flow state as described above, the actual flow velocity value proportional to the square root of the pressure. Further, a value obtained by adding a measurement error due to the secular change of the offset, which is the difference between the forward delay time and the backward delay time in the measurement unit 12, is obtained.
That is, assuming that the pressure of the measurement channel 12 is p, the proportionality coefficient with respect to the square root of the pressure is α, and the measurement error is β, the determination target flow velocity value Q can be expressed by the following equation (4).
[0040]
[Expression 4]

[0041]
The determination target pressure deriving unit 14 in which the control device 10 functions is used to extract the flow velocity value q _ave as the determination target flow velocity value Q by the determination target flow velocity value extracting unit 13 as described above, and the average pressure p _ave of the measurement flow path 2 is extracted. Is a reliable pressure that is not affected by the pressure fluctuation of the gas f generated in a short cycle. That is, the determination target pressure extraction unit 14 determines whether the pressure change amount that is the difference between the maximum value p _max and the minimum value p _min of the pressure p is less than a predetermined set pressure change amount C of about 20 Pa ( # 205).
When the pressure change amount is less than the set pressure change amount C, the average pressure p _ave at that time is extracted as the determination target pressure P for the determination target flow velocity value Q (# 206).
[0042]
In order to extract the determination target flow velocity value Q and the determination target pressure P, the flow velocity value q _ave is less than the set minute flow velocity value A, and the flow velocity value change amount is less than a predetermined set flow velocity value change amount B. When the pressure change amount is less than the predetermined set pressure change amount C, the measuring means 12 and the pressure sensor 7 are again set at a cycle shorter than the measurement time interval, for example, at intervals of 100 msec for 5 seconds. For example, the instantaneous flow velocity value and the pressure may be measured, and the average value of the instantaneous flow velocity value and the pressure may be extracted as the determination target flow velocity value Q and the determination target pressure P.
[0043]
Further, the control device 10 stores the determination target data (Q, P) of the determination target flow velocity value Q and the determination target pressure P in the storage unit 18 by the measurement error determination means 15, which will be described in detail later. In addition, a measurement error determination process for determining a measurement error using the determination target data (Q, P), a leakage determination process for determining a leakage state, and the like are executed.
[0044]
That is, as described above, the measurement error determination unit 15 in which the control device 10 functions has the determination target flow velocity value Q, which is the flow velocity value derived by the measurement unit 12 in the non-flowing state or the minute flow state, as the determination target pressure P. Since the term proportional to the square root of the value and the constant term of the measurement error β can be expressed as an expression, the measurement error β is calculated from a plurality of determination target data (Q, P), and the occurrence of the measurement error or its extent The processing flow of the measurement error determination process will be described with reference to FIG.
[0045]
First, when the determination target data (Q, P) is derived by the determination target flow velocity value extraction unit 13 and the determination target pressure deriving unit 14, the measurement error determination unit 15 sequentially acquires the determination target data (Q, P). (# 301).
[0046]
Further, the measurement error determination means 15 uses the determination target data (Q, P) derived at the beginning of the determination period such as one day or one month as the first determination target data (Q (1), P (1)). (# 302).
[0047]
Further, after acquiring the first determination target data (Q (1), P (1)), the determination target pressure P is the pressure P (1 in the first determination target data (Q (1), P (1)). ) Is equal to or higher than a predetermined set pressure change rate D such as 0.1 (# 303). If the pressure change rate is 0.1 or higher, the determination at that time The target data (Q, P) is acquired as second determination target data (Q (2), P (2)) (# 304).
[0048]
On the other hand, when the pressure change rate is less than the set pressure change rate D, the determination target data (Q, P) at that time and the first determination target data (Q (1), P (1)) Since the pressure P is not sufficiently different from each other, it is assumed that the correlation between the flow velocity value and the pressure cannot be obtained accurately using the two data, and the determination target data (Q, P) is determined as the second determination. The next determination target data (Q, P) is acquired without using the target data (Q (2), P (2)).
[0049]
In addition, when the said pressure change rate was more than the predetermined setting pressure change rate D, the 2nd determination object data (Q (2), P (2)) was acquired. When the flow rate value change rate with respect to the flow rate value Q (1) in the first determination target data (Q (1), P (1)) is equal to or higher than a predetermined set flow rate value change rate, the second determination target data (Q (2), P (2)) may be acquired.
[0050]
Then, the measurement error determination means 15 uses the first determination target data (Q (1), P (1)) and the second determination target data (Q (2), P (2)) thus acquired as described above. By solving the simultaneous equations derived by substituting into the equation (4), the measurement error β in the measuring means 12 is calculated (# 305), and the absolute value of the measurement error β is greater than or equal to a predetermined set measurement error E For example, assuming that a measurement error that cannot be ignored is generated in the measurement means 12, for example, a measurement error occurrence notification process is performed by outputting a message indicating the occurrence of the measurement error to the output unit 19 (# 307).
[0051]
The degree of measurement error may be determined at a plurality of stages such as large, medium, and small according to the absolute value of the measurement error β, and the degree of measurement error may be reported. . For example, if the determination error β is 5 L / h or more, it is determined that a fatal determination error has occurred, the notification process is performed, and the flow of the gas f is interrupted, so that the determination error β is less than 5 L / h and 1.5 L / H or higher, only the above notification process is performed, and if the determination error β is less than 1.5 L / h, it is determined that no determination error has occurred, and the data is reset and the measurement error determination process is executed again. Can do.
[0052]
In addition, immediately after the absolute value of the measurement error β becomes equal to or greater than the predetermined set measurement error E, the notification process of the occurrence of the measurement error is not performed, but the absolute value of the measurement error β is set to the predetermined set measurement error E multiple times. When it becomes above, you may perform the report processing etc. of measurement error generation.
[0053]
Also, the measurement error is more likely when the first determination target data (Q (1), P (1)) and the second determination target data (Q (2), P (2)) are derived to a certain degree of time. Therefore, it is preferable that the measurement error determination process is repeatedly performed by resetting both the data to 0 for each determination period such as one month.
[0054]
In the measurement error determination process, when it is determined that the absolute value of the measurement error β is less than the predetermined setting measurement error E and no measurement error has occurred, for example, after a predetermined period of 30 days or the like has elapsed, The control device 10 may be configured to perform the measurement error determination process again.
[0055]
Moreover, the leakage determination means 16 in which the control device 10 functions performs a leakage determination process for determining a leakage state when the gas f is continuously flowing in the measurement channel 2 for a predetermined setting period such as one month. The configuration will be described based on the processing flow of FIG.
[0056]
That is, the elapsed time t is reset to 0 (# 401), the determination target flow velocity value Q derived every 30 seconds is acquired (# 402), and the measurement error determination is performed from the determination target flow velocity value Q. It is determined whether the value obtained by subtracting the measurement error β derived in the process is greater than or equal to a predetermined setting determination value F (# 403).
The elapsed time t from when the value obtained by subtracting the measurement error β from the determination target flow velocity value Q is equal to or greater than a predetermined setting determination value F has reached a predetermined setting period G such as one month. (# 404), if it is determined that the elapsed time t has reached the predetermined set period G, it is determined that the gas f is continuously flowing for a predetermined set period such as one month. In addition to the predetermined leakage notification process, a blocking process for blocking the flow of the gas f can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a situation in which a flow velocity value is measured by an ultrasonic meter device. FIG. 2 is a processing flow diagram showing propagation time measurement, instantaneous flow velocity value derivation processing, and pressure derivation processing. Process flow diagram showing flow velocity value and judgment target pressure derivation processing [FIG. 4] Process flow diagram showing measurement error judgment processing [FIG. 5] Process flow diagram showing leakage judgment processing [Explanation of symbols]
1: Ultrasonic meter device (device of the present invention)
2: Measurement channel 5: Transceiver 104: Controller 11: Propagation time measurement means 12: Measurement means 13: Determination target flow velocity value extraction means 14: Determination target pressure derivation means 15: Measurement error determination means 16: Leakage determination means 18: Storage unit f: Gas (fluid)

Claims

A pair of transducers are installed on the upstream side and downstream side of the measurement channel through which the fluid flows, and the order in which the ultrasonic waves propagate between the transducers in the forward direction along the flow direction of the fluid flowing through the measurement channel. Propagation time measuring means for measuring the direction propagation time and the reverse propagation time in which the ultrasonic wave propagates between the transducers in the reverse direction opposite to the forward direction, and the measurement was performed by using the propagation time measuring means. An ultrasonic meter device comprising measurement means for deriving a flow velocity value related to the flow velocity of the fluid flowing through the measurement flow path from the forward propagation time and the backward propagation time,
A determination target flow velocity value extracting means for extracting a determination target flow velocity value maintained below a predetermined set minute flow velocity value from the flow velocity value derived by the measurement means;
Determination target pressure deriving means for deriving a determination target pressure that is a pressure of the measurement flow path corresponding to the determination target flow velocity value extracted by the determination target flow velocity value extraction means;
An ultrasonic meter device comprising: a measurement error determination unit that determines a measurement error in the measurement unit from a plurality of determination target flow velocity values and the determination target pressure.

2. The apparatus according to claim 1, wherein the measurement unit is configured to derive an average value of instantaneous flow velocity values derived by operating the propagation time measurement unit at predetermined measurement time intervals within a predetermined set time as the flow velocity value. The ultrasonic meter device according to the description.

The measuring means is configured to derive a maximum value and a minimum value of the plurality of instantaneous flow velocity values together with the flow velocity value;
The determination target flow velocity value extracting means has a flow velocity value change in which the flow velocity value derived by the measuring device is less than the minute flow velocity value and is a difference between the maximum value and the minimum value derived by the measuring device. The ultrasonic meter device according to claim 2, wherein when the amount is less than a predetermined set flow rate value change amount, the flow rate value is extracted as the determination target flow rate value.