JP4225801B2

JP4225801B2 - Ultrasonic flow meter

Info

Publication number: JP4225801B2
Application number: JP2003045403A
Authority: JP
Inventors: 茂行伊藤
Original assignee: Ricoh Elemex Corp
Current assignee: Ricoh Elemex Corp
Priority date: 2003-02-24
Filing date: 2003-02-24
Publication date: 2009-02-18
Anticipated expiration: 2023-02-24
Also published as: JP2004257738A

Description

【０００１】
【発明の属する技術分野】
本発明は、超音波流量計に関する。
【０００２】
【従来の技術】
従来、都市ガス、水などの流体の流量を計測する流量計測装置として、超音波を利用して流速を測定する超音波流量計が知られている。例えば、特許文献１には、超音波センサによって流量測定するためのガス導通路を長手方向に沿って傾斜配置させることにより、ガス中に含まれる不純物が導通路内に堆積せず落下し、長期にわたりガス流量の正確な計測を可能にする技術が開示されている。
【０００３】
【特許文献１】
特許第３３３４８５７号公報
【０００４】
【発明が解決しようとする課題】
ところで、超音波センサ（超音波送受信部）を装着した当初の状態においては、ガス流量等の正確な計測が可能であるが、経時変化等により音圧感度特性が劣化し、測定精度が低下するので、超音波送受信部を交換しなければならない場合がある。特に、ガスメータでは１０年経過時のメータ交換が法律で義務付けられているので、回収した超音波流量計のリサイクルを行うためには、超音波送受信部の取り外し・取り替えが必要となる。さらには、超音波流量計（超音波センサ）の組立後の検査で所定の性能・精度が得られないとき（作動不良が発見されたとき）にも、超音波送受信部の取り替えを要する場合がある。しかし、特許文献１に示すような超音波流量計では、密閉構造に形成された密閉室内においてその密閉室を２つに分割する隔壁に超音波センサを設置するための導通路が固定されているため、超音波センサ（超音波送受信部）の取り外し・取り替えは非常に困難であった。
【０００５】
そこで本発明の課題は、超音波センサを設置するための流路の密閉性、組立性を維持しながら、超音波センサ（とりわけ超音波送受信部）の着脱性（取り外し・取り替えの容易性）を向上させることができる超音波流量計を提供することにある。
【０００６】
【課題を解決するための手段及び発明の効果】
上記課題を解決するために本発明に係る超音波流量計は、
それぞれ外面に開口する流入口及び流出口の間に流体を通過させるための本体流路が内部に形成された本体ユニットと、
その本体ユニットに形成された本体流路切除部に流体の流れ方向と交差する方向から嵌合したときに前記本体流路と接続される中間流路が内部に貫通形成されるとともに、前記本体流路切除部と連通し前記本体ユニットの外面に開口する窓孔に対応して嵌合方向の前方側に突出部が形成され、その突出部に前記中間流路を通過する流体の流量を測定するための超音波センサが着脱可能に取り付けられた中間流路形成ユニットとを備え、
前記中間流路が前記本体流路と連通するように前記中間流路形成ユニットを前記本体ユニットに嵌合することにより、前記突出部がその本体ユニットの窓孔から外部に突出してその窓孔を密閉するとともに、外部から前記超音波センサを着脱可能とすることを特徴とする。
【０００７】
この超音波流量計によれば、本体ユニットの窓孔を通り中間流路形成ユニットの突出部が外部に突出しているので、外部から超音波センサのみを容易に取り外し・取り替えすることができ、作業性・組立性が向上する。また、このように超音波センサの交換が容易になることによって、超音波センサのリサイクル使用も促進される。さらに、超音波流量計の組立後の検査において、超音波センサに何らかの不具合（作動不良等）が発見された場合でも、速やかに不具合の発生した超音波センサを取り外し・取り替えすることができる。
【０００８】
そして、上記課題を解決するために本発明に係る超音波流量計の第一の具体的態様は、
それぞれ外面に開口する流入口及び流出口の間に流体を通過させるための本体流路が内部に形成された本体部と、その本体部に形成された本体流路切除部を外部から覆う蓋部とを有する本体ユニットと、
前記本体部の本体流路切除部に流体の流れ方向と交差する方向から嵌合したときに前記本体流路と接続される中間流路が内部に貫通形成されるとともに、前記本体流路切除部と連通し前記本体部の外面に開口する窓孔に対応して嵌合方向の前方側に突出部が形成され、その突出部に前記中間流路を通過する流体の流量を測定するための超音波センサが着脱可能に取り付けられた中間流路形成ユニットとを備え、
前記中間流路が前記本体流路と連通するように前記中間流路形成ユニットを前記本体部に嵌合することにより、前記突出部がその本体部の窓孔から外部に突出してその窓孔を密閉するとともに、外部から前記超音波センサを着脱可能とすることを特徴とする。
【０００９】
この超音波流量計によれば、本体部の窓孔を通り中間流路形成ユニットの突出部を外部に突出させて、外部から超音波センサのみを容易に取り外し・取り替えすることができるとともに、蓋部によって本体部の本体流路切除部と中間流路形成ユニットとを外部から覆って密閉構造とすることができる。
【００１０】
その際、超音波流量計の第一の具体的態様においては、
中間流路形成ユニットに形成された中間流路のうち少なくとも一部分が直線状に形成され、その直線状中間流路は、流体の流れ方向に直交する断面において、本体流路切除部への嵌合方向を長辺となす矩形状に形成されるとともに、
超音波センサは、直線状中間流路の流れ方向直交断面のうち嵌合方向前方側の短辺を形成する壁面に一対の送受信部が流れ方向に所定距離を隔てて取り付けられ、かつその嵌合方向後方側の短辺を形成する壁面を反射面とする反射型Ｖ字配列に構成され、送受信部が外部から個別に着脱可能とされていることが望ましい。
【００１１】
これによって、直線状中間流路に設置された一対の送受信部により超音波センサが反射型Ｖ字配列に構成され、矩形状断面流路の嵌合方向後方側の短辺を形成する壁面を反射面としている。したがって、直線状中間流路と矩形状断面流路とにより流体の流速分布が省スペースで均一化され、かつ流速をより速く（大きく）した状態で測定が可能となり、超音波流量計の高精度化と小型化を図ることができる。
【００１２】
また、上記課題を解決するために本発明に係る超音波流量計の第二の具体的態様は、
それぞれ外面に開口する流入口及び流出口の間に流体を通過させるための本体流路が内部に形成された本体部と、その本体部に形成された本体流路切除部を外部から覆う蓋部とを有する本体ユニットと、
前記本体部の本体流路切除部に流体の流れ方向と交差する方向から嵌合したときに前記本体流路と接続される中間流路が内部に貫通形成されるとともに、前記蓋部の厚さ方向において前記本体流路切除部が外部と連通するように前記蓋部に貫通形成された窓孔に対応して嵌合方向の後方側に突出部が形成され、その突出部に前記中間流路を通過する流体の流量を測定するための超音波センサが着脱可能に取り付けられた中間流路形成ユニットとを備え、
前記中間流路が前記本体流路と連通するように前記中間流路形成ユニットを前記本体部に嵌合することにより、前記突出部が前記蓋部の窓孔から外部に突出してその窓孔を密閉するとともに、外部から前記超音波センサを着脱可能とすることを特徴とする。
【００１３】
この超音波流量計によれば、蓋部の窓孔を通り中間流路形成ユニットの突出部を外部に突出させて、外部から超音波センサのみを容易に取り外し・取り替えすることができるとともに、蓋部によって本体部の本体流路切除部と中間流路形成ユニットとを外部から覆って密閉構造とすることができる。
【００１４】
このとき、超音波流量計の第二の具体的態様においては、
中間流路形成ユニットに形成された中間流路のうち少なくとも一部分が直線状に形成され、その直線状中間流路は、流体の流れ方向に直交する断面において、本体流路切除部への嵌合方向を長辺となす矩形状に形成されるとともに、
超音波センサは、直線状中間流路の流れ方向直交断面のうち嵌合方向後方側の短辺を形成する壁面に一対の送受信部が流れ方向に所定距離を隔てて取り付けられ、かつその嵌合方向前方側の短辺を形成する壁面を反射面とする反射型Ｖ字配列に構成され、送受信部が外部から個別に着脱可能とされていることが望ましい。
【００１５】
これによって、直線状中間流路に設置された一対の送受信部により超音波センサが反射型Ｖ字配列に構成され、矩形状断面流路の嵌合方向前方側の短辺を形成する壁面を反射面としている。したがって、第一の具体的態様の超音波流量計と同様に、直線状中間流路と矩形状断面流路とにより流体の流速分布が省スペースで均一化され、かつ流速をより速く（大きく）した状態で測定が可能となり、超音波流量計の高精度化と小型化を図ることができる。
【００１６】
また、第一又は第二の具体的態様において、流入口及び流出口を、直方体形状を有する本体部の上面にそれぞれ開口し、かつ中間流路形成ユニットを、流体の流れ方向とほぼ直交する方向から本体部の本体流路切除部に嵌合することにより、直線状中間流路を、本体流路とほぼ直交するとともに本体部の下面に沿って配設することができる。これによって、本体部のコンパクト化を図りつつ、直線状中間流路の長さひいては一対の送受信部の相互間隔を十分長くとれ、測定精度が向上する。
同じく、第一又は第二の具体的態様において、本体部に嵌合した中間流路形成ユニットを嵌合方向後方側から押圧・保持した状態で、蓋部を本体部に固定することができる。これによって、中間流路形成ユニットが本体部にしっかり嵌合され密閉性が保たれる。その際、蓋部と本体部とは、ねじ、ボルト等の締結部材を用い、パッキン、ガスケット等のシール材を介して固定するとよい。
【００１７】
次に、本発明の超音波流量計において、中間流路形成ユニットと本体ユニットの本体流路切除部との嵌合面を嵌合方向に沿って傾斜する傾斜面に形成することができる。また、本発明の超音波流量計において、少なくとも中間流路形成ユニットと本体ユニットの本体流路切除部とを、熱膨張率が同一又は近似の材料で構成することができる。
これらによって、中間流路形成ユニットと本体流路切除部との密閉性を確実にして測定精度を向上させるとともに、流量測定部からのガス漏れ等の危険を防止している。なお、鋳造性と軽量化とを勘案して、中間流路形成ユニットと本体ユニットとは同一のアルミダイカスト材料（例えば、ＪＩＳＨ５３０２で規定されるＡＤＣ１２；線膨張係数２１×１０^−６／Ｋ）で構成してもよい。勿論、中間流路形成ユニットと本体ユニットとの少なくとも一方に、アルミダイカスト材料と同等の熱膨張率を有する樹脂材料（例えば、グラスファイバ入りＡＢＳ樹脂）等を採用してもよい。
【００１８】
ところで、本発明の前提となる超音波流量計は、
それぞれ外面に開口する流入口及び流出口の間に流体を通過させるための本体流路が内部に形成された本体ユニットと、
その本体ユニットに形成された本体流路切除部に流体の流れ方向と交差する方向から嵌合したときに前記本体流路と接続される中間流路が内部に貫通形成されるとともに、前記中間流路を通過する流体の流量を測定するための超音波センサが取り付けられた中間流路形成ユニットとを備え、
前記中間流路が前記本体流路と連通するように前記中間流路形成ユニットを前記本体ユニットに嵌合することにより、前記本体流路切除部が前記中間流路形成ユニットで密閉されるものであってもよい。
【００１９】
このような超音波流量計にあっては、超音波センサは中間流路形成ユニットと一体で本体ユニットに対して着脱可能であってもよい。流体流通空間であると同時に流量計測空間でもある中間流路の内壁面には、本体流路よりも高い寸法精度（例えば、超音波の伝搬距離に関与する流路寸法や流速分布を乱さないための表面精度）が求められ、高度な加工技術が必要となる。中間流路を含む部分を中間流路形成ユニットとして本体部分（本体ユニット）から分割形成することによって、メンテナンスの容易性に加えて、加工性の向上と製造コストの低減とを同時に満たすことができる。なお、中間流路の断面形状及び／又は断面積の異なる中間流路形成ユニットのみの交換により、流量（流速）の測定可能範囲（使用最大流量と呼ぶ）を変更できるので、本体ユニットの汎用性を高め用途を拡大することができる。
【００２０】
【発明の実施の形態】
（実施例１）
次に、本発明の実施の形態を図面を用いて説明する。図１は、一般住宅用ガスメータ等として用いられる超音波流量計の一実施例の全体斜視図を示す。この超音波流量計１００は、本体ユニット１０と中間流路形成ユニット２０と遮断弁３０とから構成され、本体ユニット１０は本体部１１と蓋部１７とからなる。
【００２１】
図２は超音波流量計１００の正面断面図を示し、図２のＡ−Ａ断面図が図３に、Ｂ−Ｂ断面図が図５にそれぞれ表わされている。また、図４は中間流路形成ユニット２０の斜視図を表わしている。
図２に示すように、本体部１１は全体として直方体形状を有し、その上面には、上流側のガス配管に接続される流入口１２及び下流側のガス配管に接続される流出口１３がそれぞれ開口している。また、その内部には、流入口１２と流出口１３との間にガス（流体）を通過させるための本体流路１４が形成されている。本体部１１の下部には、図２の背面側から手前側（図５の嵌合方向）に向けて本体流路切除部１５が形成され、この本体流路切除部１５は、図５に示すようにパッキン１７ａ（シール材）を介し蓋部１７によって外部から覆われている。本体部１１の嵌合方向前方側（図２の手前側）の外面には、本体流路切除部１５と連通する一対の窓孔１６，１６が開口している。
【００２２】
図３に示すように、中間流路形成ユニット２０の内部には、本体部１１の本体流路切除部１５にガスの流れ方向と直交する方向（嵌合方向）から嵌合したときに本体流路１４と接続される中間流路２１が貫通形成されている。この中間流路２１は、本体流路１４と滑らかに連続する入口側連結流路２１ｂ，出口側連結流路２１ｃと、両端で両連結流路２１ｂ，２１ｃと連なるとともに、本体流路１４とほぼ直交する形態で本体部１１の下面に沿って配設される直線状中間流路２１ａとから構成されている（図２参照）。また、中間流路形成ユニット２０には、本体部１１に開口する一対の窓孔１６，１６に対応して嵌合方向の前方側に一対の突出部２２，２２がそれぞれ一体形成されている。さらに、中間流路形成ユニット２０の一対の突出部２２，２２には、直線状中間流路２１ａを通過するガスの流量を測定するために、超音波センサ２３の一対の送受信部２３ａ，２３ｂがそれぞれ着脱可能に取り付けられている。直線状中間流路２１ａの軸直交断面積を本体流路１４の軸直交断面積よりも小とし（絞り）、直線状中間流路２１ａを流れるガスの流速を速くして超音波センサ２３による流量（流速）の測定精度が高くなるようにしている。なお、流入口１２と中間流路２１との間の本体流路１４には、本体流路１４のガスの流れを遮断する遮断弁３０が設けられている（図２参照）。
【００２３】
したがって、図３において、中間流路２１が本体流路１４と連通するように中間流路形成ユニット２０を本体部１１の本体流路切除部１５に嵌合すると、各突出部２２，２２が本体部１１の各窓孔１６，１６からそれぞれ外部に突出する。そして、各突出部２２，２２はパッキン１６ａ（シール材）を介し各窓孔１６，１６をそれぞれ密閉する。さらに、超音波センサ２３の各送受信部２３ａ，２３ｂが、取付ねじ２３ｃ，２３ｃ（取付部材）と押圧板（押圧部材；図示せず）によって外部から各突出部２２，２２にそれぞれ着脱可能に固定されている。
【００２４】
図５（流体の流れ方向に直交する断面）において、直線状中間流路２１ａは、本体流路切除部１５への嵌合方向を長辺Ｌ、上下方向を短辺Ｓとする矩形状に形成されている。そして、超音波センサ２３は次のような反射型Ｖ字配列に構成されている。すなわち、直線状中間流路２１ａの流れ方向直交断面のうち嵌合方向前方側の短辺を形成する壁面（取付面）２１ｄに一対の送受信部２３ａ，２３ｂが流れ方向に所定距離Ｗを隔てて取り付けられ、嵌合方向後方側の短辺を形成する壁面を反射面２１ｅとする（図３参照）。
【００２５】
図５に示すように、中間流路形成ユニット２０と本体ユニット１１の本体流路切除部１５との各々の嵌合面２０ａ，１５ａは、嵌合方向に沿って傾斜する傾斜面に形成されている。具体的には、直線状中間流路２１ａを挟んで上下の嵌合面２０ａ，１５ａが、嵌合方向前方側ほど近接するようなテーパを有している。本体ユニット１０（本体部１１及び蓋部１７）と中間流路形成ユニット２０とは、ともにアルミダイカスト材料ＡＤＣ１２（ＪＩＳＨ５３０２；線膨張係数２１×１０^−６／Ｋ）で構成されている。このように、嵌合面２０ａ，１５ａのテーパ形成及び本体ユニット１０と中間流路形成ユニット２０との同一材料構成により、中間流路形成ユニット２０と本体流路切除部１５との嵌合時又は熱膨張時の抜けを防止し、本体流路切除部１５と窓孔１６との間の気密性を保持している。
【００２６】
本体部１１（本体流路切除部１５）と中間流路形成ユニット２０とを嵌合する際に、蓋部１７により中間流路形成ユニット２０を嵌合方向後方側から押圧・保持し、パッキン１７ａ（シール部材）と固定ねじ１７ｂ（固定部材）とによって蓋部１７を本体部１１に固定する。本体部１１（本体流路切除部１５）と中間流路形成ユニット２０とが確実に嵌合され、本体部１１と蓋部１７とが固定されるので、本体部１１・蓋部１７・中間流路形成ユニット２０の三者の気密性が十分に保持される。
【００２７】
図１に示すように、超音波センサ２３の送受信部２３ａ，２３ｂ（センサ素子）で得られた出力信号は、リード線２５，２５を介して流量演算処理回路２４に送信されてガス流量が算出され、流量表示部（図示せず）等を用いて報知される。これらの送受信部２３ａ，２３ｂ、流量演算処理回路２４、リード線２５，２５、流量表示部等は流量測定部Ｍを構成している。リード線２５，２５は、窓孔１６，１６から外部に突出して設けられる超音波センサ２３（送受信部２３ａ，２３ｂ）から引き出されるので、その芯線部を通じて測定ガスが外部に漏れ出して、気密性が不十分となったり、測定精度が低下したりすることがない。このように、本体部１１・蓋部１７・中間流路形成ユニット２０の三者の気密性が確保され、リード線２５，２５が流路外に位置するので、漏れ出したガスに電気部品の火花が引火して火災が発生することもない。なお、２６は、入口側連結流路２１ｂと直線状中間流路２１ａとの間に設けられ、流路内での測定ガス流の乱れを抑え速度分布を均一化するための整流部材である（図２参照）。
【００２８】
したがって、このような超音波流量計１００を組み立てるには、本体部１１の本体流路切除部１５に中間流路形成ユニット２０を、互いの嵌合面１５ａ，２０ａを合わせながら嵌合する。そして、本体部１１の窓孔１６，１６から中間流路形成ユニット２０の突出部２２，２２を外部に突出させる。蓋部１７によって中間流路形成ユニット２０を嵌合方向後方側から本体部１１側に押圧し、パッキン１７ａを挟んで固定ねじ１７ｂにより蓋部１７を本体部１１に固定する。
【００２９】
超音波センサの経時変化等による音圧感度特性の劣化、あるいは超音波流量計のリサイクルや組立時検査不合格等のために送受信部２３ａ，２３ｂを取り外す（取り替える）には、送受信部２３ａ，２３ｂの取付ねじ２３ｃ，２３ｃと押圧板を取り外せばよい。
【００３０】
（実施例２）
次に、超音波流量計の他の実施例について説明する。実施例２として示す超音波流量計２００は、図６において図３（実施例１）に代るＡ−Ａ断面図で表わされ、図７において図５（実施例１）に代るＢ−Ｂ断面図で表わされる。この超音波流量計２００も、本体ユニット１０と中間流路形成ユニット２０と遮断弁３０とから構成され、本体ユニット１０は本体部１１と蓋部１７とからなる。
【００３１】
図６において、超音波流量計２００が超音波流量計１００（実施例１）と異なる点は次の通りである。すなわち、この実施例では、窓孔１６は蓋部１７に貫通形成され、蓋部１７の厚さ方向において本体流路切除部１５が外部と連通する。したがって、中間流路形成ユニット２０の突出部２２が蓋部１７の窓孔１６から外部に突出して窓孔１６を密閉している。また、超音波センサ２３は次のような反射型Ｖ字配列に構成されている。すなわち、直線状中間流路２１ａの流れ方向直交断面のうち嵌合方向後方側の短辺を形成する壁面（取付面）２１ｄに一対の送受信部２３ａ，２３ｂが流れ方向に所定距離Ｗを隔てて取り付けられ、嵌合方向前方側の短辺を形成する壁面を反射面２１ｅとする。なお、蓋部１７には、遮断弁３０を挿入するために、厚さ方向に貫通形成された挿入孔も形成されているが、図示を省略している。
【００３２】
（変形例）
以上の実施例においては、超音波センサ（送受信部）の配置と超音波の通る径路（測線という）として反射型Ｖ字配列を採用した場合について説明した。反射型Ｖ字配列では、一対の送受信部を流れ方向に沿って同じ側に集中配置できるので、送受信部の着脱を同じ方向から行える利点がある。超音波流量計における超音波センサ（送受信部）の測線方式には、反射型Ｖ字配列の他にも多くの種類が知られている。他の測線方式に対する本発明の適用例について以下に説明する。
【００３３】
（１）透過型バイパス配列（図８（ａ））
嵌合方向の前方側にバイパス部１２２が一体形成され、そのバイパス部１２２にガス流量を測定するための透過型超音波センサ１２３（送受信部１２３ａ，１２３ｂ）が着脱可能に取り付けられている。反射型Ｖ字配列の場合と同様に一対の送受信部１２３ａ，１２３ｂを流れ方向に沿って同じ側に集中配置できる。
【００３４】
（２）透過型Ｖ字配列（図８（ｂ））
１個の送信部２２３ａから発せられた超音波を流れ方向に沿って所定距離離間して配置された一対の受信部２２３ｂ，２２３ｂで受信する方式である。この方式では、送信部２２３ａと受信部２２３ｂ，２２３ｂとは流れ方向の両側に分離して配置される。
【００３５】
（３）交差型Ｘ配列（図８（ｃ））
流れ方向に沿って所定距離離間して配置された一対の送信部３２３ａ，３２３ａから発せられた超音波を流れ方向に沿って所定距離離間して配置された一対の受信部３２３ｂ，３２３ｂで受信する方式である。この方式は上記した図８（ｂ）の方式において、送信部を１個から一対に増設したものに相当する。
【００３６】
以上の実施例及び変形例においては、本体ユニット１０が、本体流路１４を内部に有する本体部１１と本体部１１を外部から覆う蓋部１７とから構成される場合についてのみ説明したが、本体ユニット１０は次のような構成であってもよい。すなわち、本体ユニットは半割り状の本体流路を各々有する第一本体部と第二本体部とを合掌構成してもよい。ただし、この場合には窓孔は第一本体部と第二本体部とのうち少なくともいずれか一方に設けられ、蓋部は設けても設けなくてもよい。
【図面の簡単な説明】
【図１】本発明に係る超音波流量計の一実施例の全体斜視図。
【図２】図１の正面断面図。
【図３】図２のＡ−Ａ断面図。
【図４】中間流路形成ユニットの斜視図。
【図５】図２のＢ−Ｂ断面図。
【図６】本発明に係る超音波流量計の他の実施例の図３に代るＡ−Ａ断面図。
【図７】図５に代るＢ−Ｂ断面図。
【図８】本発明に係る超音波流量計の変形例を示す説明図。
【符号の説明】
１０本体ユニット
１１本体部
１２流入口
１３流出口
１４本体流路
１５本体流路切除部
１５ａ嵌合面
１６窓孔
１７蓋部
２０中間流路形成ユニット
２０ａ嵌合面
２１中間流路
２２突出部
２３超音波センサ
２３ａ，２３ｂ送受信部
３０遮断弁
１００，２００超音波流量計[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic flow meter.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an ultrasonic flowmeter that measures flow velocity using ultrasonic waves is known as a flow measurement device that measures the flow rate of a fluid such as city gas or water. For example, in Patent Document 1, by disposing gas conduction paths for measuring a flow rate with an ultrasonic sensor along the longitudinal direction, impurities contained in the gas fall without depositing in the conduction paths, A technique that enables accurate measurement of the gas flow rate is disclosed.
[0003]
[Patent Document 1]
Japanese Patent No. 3334857 gazette
[Problems to be solved by the invention]
By the way, in the initial state where the ultrasonic sensor (ultrasonic transmission / reception unit) is mounted, it is possible to accurately measure the gas flow rate or the like, but the sound pressure sensitivity characteristic is deteriorated due to a change over time, and the measurement accuracy is lowered. Therefore, the ultrasonic transmission / reception unit may have to be replaced. In particular, since a gas meter requires that the meter be replaced after 10 years, the ultrasonic transmitter / receiver must be removed and replaced in order to recycle the collected ultrasonic flowmeter. Furthermore, the ultrasonic transmitter / receiver may need to be replaced even when the specified performance and accuracy cannot be obtained in the post-assembly inspection of the ultrasonic flowmeter (ultrasonic sensor) (when a malfunction is found). is there. However, in the ultrasonic flowmeter as shown in Patent Document 1, a conduction path for installing an ultrasonic sensor is fixed to a partition wall that divides the sealed chamber into two in a sealed chamber formed in a sealed structure. Therefore, it has been very difficult to remove and replace the ultrasonic sensor (ultrasonic transceiver).
[0005]
Accordingly, an object of the present invention is to improve the detachability (ease of removal and replacement) of the ultrasonic sensor (particularly, the ultrasonic transmission / reception unit) while maintaining the sealing property and assembly property of the flow path for installing the ultrasonic sensor. An object of the present invention is to provide an ultrasonic flowmeter that can be improved.
[0006]
[Means for Solving the Problems and Effects of the Invention]
In order to solve the above problems, an ultrasonic flowmeter according to the present invention is:
A main body unit in which a main body channel for allowing fluid to pass between an inlet and an outlet opening on the outer surface is formed, and
An intermediate flow path that is connected to the main body flow path when the main body flow path cutting portion formed in the main body unit is fitted from the direction intersecting the fluid flow direction is formed through the inner flow path. A protrusion is formed on the front side in the fitting direction in correspondence with the window hole that opens to the outer surface of the main body unit and communicates with the path cutting portion, and measures the flow rate of the fluid that passes through the intermediate flow path at the protrusion. An intermediate flow path forming unit to which an ultrasonic sensor for detachable attachment is attached,
By fitting the intermediate flow path forming unit into the main body unit so that the intermediate flow path communicates with the main body flow path, the projecting portion protrudes outside from the window hole of the main body unit, thereby opening the window hole. The ultrasonic sensor is sealed and detachable from the outside.
[0007]
According to this ultrasonic flow meter, since the protruding portion of the intermediate flow path forming unit protrudes outside through the window hole of the main unit, it is possible to easily remove and replace only the ultrasonic sensor from the outside. Improves assembly and assembly. In addition, since the ultrasonic sensor can be easily replaced in this way, the recycling use of the ultrasonic sensor is also promoted. Furthermore, even if any defect (operation failure or the like) is found in the ultrasonic sensor in the inspection after the assembly of the ultrasonic flowmeter, the ultrasonic sensor in which the defect has occurred can be quickly removed and replaced.
[0008]
And in order to solve the said subject, the 1st specific aspect of the ultrasonic flowmeter which concerns on this invention is as follows.
A main body part in which a main body channel for allowing a fluid to pass between an inlet and an outlet opening on the outer surface is formed inside, and a lid part for covering the main body channel cutting part formed in the main body part from the outside A main unit having
An intermediate flow path connected to the main body flow path when the main body flow path cutting section of the main body section is fitted from a direction intersecting with the fluid flow direction is formed through the body flow path cutting section. A protrusion is formed on the front side in the fitting direction in correspondence with the window hole opened on the outer surface of the main body, and the protrusion is used to measure the flow rate of the fluid passing through the intermediate flow path. An intermediate flow path forming unit to which a sonic sensor is detachably attached,
By fitting the intermediate flow path forming unit to the main body so that the intermediate flow path communicates with the main body flow path, the protruding portion protrudes outside from the window hole of the main body portion, and the window hole is formed. The ultrasonic sensor is sealed and detachable from the outside.
[0009]
According to this ultrasonic flow meter, the protruding portion of the intermediate flow path forming unit protrudes outside through the window hole of the main body, and only the ultrasonic sensor can be easily removed and replaced from the outside, and the lid The part can cover the main body flow path cutting part and the intermediate flow path forming unit of the main body part from the outside to form a sealed structure.
[0010]
At that time, in the first specific embodiment of the ultrasonic flowmeter,
At least a part of the intermediate flow path formed in the intermediate flow path forming unit is formed in a straight line, and the straight intermediate flow path is fitted to the main body flow path cutting portion in a cross section orthogonal to the fluid flow direction. It is formed in a rectangular shape with the direction as the long side,
In the ultrasonic sensor, a pair of transmission / reception parts are attached to a wall surface forming a short side on the front side in the fitting direction in a cross section orthogonal to the flow direction of the straight intermediate flow path, and the fitting is performed at a predetermined distance in the flow direction. It is desirable that the reflecting wall is formed as a reflective V-shaped array having a wall surface forming a short side on the rear side in the direction, and the transmitting / receiving unit is individually removable from the outside.
[0011]
As a result, the ultrasonic sensor is configured in a reflective V-shaped array by a pair of transmission / reception units installed in the straight intermediate flow path, and reflects the wall surface forming the short side on the rear side in the fitting direction of the rectangular cross-section flow path. It is a surface. Therefore, the flow rate distribution of the fluid is made uniform in a space-saving manner by the straight intermediate flow path and the rectangular cross-section flow path, and measurement can be performed in a state where the flow speed is faster (larger), and the ultrasonic flowmeter has high accuracy. And miniaturization can be achieved.
[0012]
In order to solve the above-mentioned problem, the second specific aspect of the ultrasonic flowmeter according to the present invention is:
A main body part in which a main body channel for allowing a fluid to pass between an inlet and an outlet opening on the outer surface is formed inside, and a lid part for covering the main body channel cutting part formed in the main body part from the outside A main unit having
An intermediate flow path connected to the main body flow path when the main body flow path cutting portion of the main body section is fitted from a direction intersecting the fluid flow direction is formed through the inside, and the thickness of the lid portion A projection is formed on the rear side in the fitting direction corresponding to the window hole formed through the lid so that the main body channel cutout portion communicates with the outside in the direction, and the intermediate channel is formed in the projection. An intermediate flow path forming unit to which an ultrasonic sensor for measuring the flow rate of the fluid passing through is detachably attached,
By fitting the intermediate flow path forming unit to the main body so that the intermediate flow path communicates with the main body flow path, the protruding portion protrudes outside from the window hole of the lid portion, thereby opening the window hole. The ultrasonic sensor is sealed and detachable from the outside.
[0013]
According to this ultrasonic flow meter, the protruding portion of the intermediate flow path forming unit can be protruded outside through the window hole of the lid portion, and only the ultrasonic sensor can be easily removed and replaced from the outside. The part can cover the main body flow path cutting part and the intermediate flow path forming unit of the main body part from the outside to form a sealed structure.
[0014]
At this time, in the second specific embodiment of the ultrasonic flowmeter,
At least a part of the intermediate flow path formed in the intermediate flow path forming unit is formed in a straight line, and the straight intermediate flow path is fitted to the main body flow path cutting portion in a cross section orthogonal to the fluid flow direction. It is formed in a rectangular shape with the direction as the long side,
In the ultrasonic sensor, a pair of transmission / reception parts are attached to a wall surface forming a short side on the rear side in the fitting direction in the cross section orthogonal to the flow direction of the straight intermediate flow path, and the fitting is performed at a predetermined distance in the flow direction. It is desirable to have a reflective V-shaped array with a wall surface forming a short side on the front side in the direction as a reflecting surface, and the transmitting / receiving unit can be individually attached and detached from the outside.
[0015]
As a result, the ultrasonic sensor is configured in a reflective V-shaped arrangement by a pair of transmission / reception units installed in the straight intermediate flow path, and reflects the wall surface forming the short side on the front side in the fitting direction of the rectangular cross-section flow path. It is a surface. Therefore, similar to the ultrasonic flowmeter of the first specific embodiment, the flow velocity distribution of the fluid is made uniform in a space-saving manner by the straight intermediate flow passage and the rectangular cross-section flow passage, and the flow velocity is made faster (larger). In this state, measurement can be performed, and the ultrasonic flowmeter can be highly accurate and downsized.
[0016]
In the first or second specific embodiment, the inlet and the outlet are respectively opened on the upper surface of the main body having a rectangular parallelepiped shape, and the intermediate flow path forming unit is in a direction substantially orthogonal to the fluid flow direction. The linear intermediate flow path can be disposed substantially perpendicular to the main body flow path and along the lower surface of the main body section by fitting to the main body flow path cutting portion of the main body section. As a result, the main body can be made compact, and the length of the linear intermediate flow path, and thus the mutual distance between the pair of transmission / reception units can be made sufficiently long, thereby improving the measurement accuracy.
Similarly, in the first or second specific mode, the lid portion can be fixed to the main body portion while the intermediate flow path forming unit fitted to the main body portion is pressed and held from the rear side in the fitting direction. As a result, the intermediate flow path forming unit is firmly fitted to the main body portion and the airtightness is maintained. At this time, the lid portion and the main body portion may be fixed using a fastening member such as a screw or a bolt and a sealing material such as a packing or a gasket.
[0017]
Next, in the ultrasonic flowmeter of the present invention, the fitting surface between the intermediate flow path forming unit and the main body channel cutting portion of the main body unit can be formed as an inclined surface that is inclined along the fitting direction. Moreover, in the ultrasonic flowmeter of the present invention, at least the intermediate flow path forming unit and the main body flow path cutting portion of the main body unit can be made of a material having the same or similar thermal expansion coefficient.
As a result, the sealing performance between the intermediate flow path forming unit and the main body flow path cutting portion is ensured to improve the measurement accuracy, and the risk of gas leakage from the flow rate measuring section is prevented. In consideration of castability and weight reduction, the intermediate flow path forming unit and the main body unit are made of the same aluminum die-cast material (for example, ADC12 defined by JIS H5302; linear expansion coefficient 21 × 10 ⁻⁶ / K). ). Of course, a resin material (for example, ABS resin containing glass fiber) having a thermal expansion coefficient equivalent to that of the aluminum die-casting material may be employed for at least one of the intermediate flow path forming unit and the main body unit.
[0018]
By the way, the ultrasonic flowmeter which is the premise of the present invention is:
A main body unit in which a main body channel for allowing fluid to pass between an inlet and an outlet opening on the outer surface is formed, and
An intermediate flow path connected to the main body flow path is formed through the inner flow path when the main body flow path cutting portion formed in the main body unit is fitted from a direction crossing the fluid flow direction. An intermediate flow path forming unit to which an ultrasonic sensor for measuring the flow rate of the fluid passing through the path is attached;
By fitting the intermediate flow path forming unit into the main body unit so that the intermediate flow path communicates with the main body flow path, the main body flow path cutting portion is sealed with the intermediate flow path forming unit. There may be.
[0019]
In such an ultrasonic flow meter, the ultrasonic sensor may be detachably attached to the main body unit integrally with the intermediate flow path forming unit. The inner wall surface of the intermediate flow path, which is the fluid flow space and the flow measurement space, has a higher dimensional accuracy than the main body flow path (for example, to not disturb the flow path dimensions and flow velocity distribution related to the ultrasonic propagation distance) Surface accuracy), and advanced processing techniques are required. By dividing and forming the portion including the intermediate flow path from the main body portion (main body unit) as an intermediate flow path forming unit, it is possible to simultaneously satisfy the improvement of workability and the reduction of manufacturing cost in addition to the ease of maintenance. . Since the measurable range of flow rate (flow velocity) (referred to as the maximum usable flow rate) can be changed by replacing only the intermediate flow path forming unit with a different cross-sectional shape and / or cross-sectional area of the intermediate flow path, the versatility of the main unit The application can be expanded.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Example 1
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an overall perspective view of an embodiment of an ultrasonic flow meter used as a general residential gas meter or the like. The ultrasonic flowmeter 100 includes a main body unit 10, an intermediate flow path forming unit 20, and a shut-off valve 30, and the main body unit 10 includes a main body portion 11 and a lid portion 17.
[0021]
2 shows a front cross-sectional view of the ultrasonic flowmeter 100, with the AA cross-sectional view of FIG. 2 shown in FIG. 3 and the BB cross-sectional view shown in FIG. FIG. 4 is a perspective view of the intermediate flow path forming unit 20.
As shown in FIG. 2, the main body 11 has a rectangular parallelepiped shape as a whole, and an inlet 12 connected to the upstream gas pipe and an outlet 13 connected to the downstream gas pipe are formed on the upper surface thereof. Each is open. In addition, a main body flow path 14 for allowing a gas (fluid) to pass between the inflow port 12 and the outflow port 13 is formed therein. A main body channel cutting section 15 is formed in the lower part of the main body section 11 from the back side in FIG. 2 toward the front side (the fitting direction in FIG. 5). The main body channel cutting section 15 is shown in FIG. Thus, it is covered from the outside by the lid part 17 through the packing 17a (sealing material). A pair of window holes 16, 16 communicating with the main body flow path cutting portion 15 are opened on the outer surface of the main body portion 11 on the front side in the fitting direction (front side in FIG. 2).
[0022]
As shown in FIG. 3, when the intermediate flow path forming unit 20 is fitted into the main body flow path cutting section 15 of the main body section 11 from a direction (fitting direction) perpendicular to the gas flow direction, An intermediate flow path 21 connected to the path 14 is formed through. The intermediate channel 21 is connected to the inlet-side connecting channel 21b and the outlet-side connecting channel 21c that are smoothly connected to the main channel 14 and to both the connecting channels 21b and 21c at both ends. It is comprised from the linear intermediate | middle flow path 21a arrange | positioned along the lower surface of the main-body part 11 with the orthogonal form (refer FIG. 2). Further, the intermediate flow path forming unit 20 is integrally formed with a pair of projecting portions 22 and 22 on the front side in the fitting direction corresponding to the pair of window holes 16 and 16 opened in the main body portion 11. Further, a pair of transmission / reception units 23a and 23b of the ultrasonic sensor 23 are provided on the pair of protrusions 22 and 22 of the intermediate flow path forming unit 20 in order to measure the flow rate of the gas passing through the linear intermediate flow path 21a. Each is detachably attached. The axial orthogonal cross-sectional area of the straight intermediate flow path 21a is made smaller (throttle) than the axial orthogonal cross-sectional area of the main body flow path 14, and the flow rate of the ultrasonic sensor 23 is increased by increasing the flow velocity of the gas flowing through the linear intermediate flow path 21a. The measurement accuracy of (flow velocity) is increased. The main body flow path 14 between the inlet 12 and the intermediate flow path 21 is provided with a shut-off valve 30 that blocks the gas flow in the main body flow path 14 (see FIG. 2).
[0023]
Therefore, in FIG. 3, when the intermediate flow path forming unit 20 is fitted to the main body flow path cutting portion 15 of the main body portion 11 so that the intermediate flow path 21 communicates with the main body flow path 14, the protrusions 22, 22 become the main body. Projecting from the window holes 16 and 16 of the portion 11 to the outside. And each protrusion part 22 and 22 seals each window hole 16 and 16 via packing 16a (sealing material), respectively. Further, the transmission / reception parts 23a and 23b of the ultrasonic sensor 23 are detachably fixed to the protrusions 22 and 22 from the outside by means of mounting screws 23c and 23c (mounting members) and a pressing plate (pressing member; not shown). Has been.
[0024]
In FIG. 5 (cross section orthogonal to the fluid flow direction), the straight intermediate flow path 21a is formed in a rectangular shape with the long side L as the fitting direction to the main body flow path cutting portion 15 and the short side S as the vertical direction. Has been. The ultrasonic sensor 23 is configured in the following reflective V-shaped arrangement. That is, a pair of transmission / reception parts 23a and 23b is separated from the wall surface (attachment surface) 21d that forms the short side on the front side in the fitting direction in the cross-section orthogonal to the flow direction of the straight intermediate flow path 21a by a predetermined distance W in the flow direction. A wall surface that is attached and forms a short side on the rear side in the fitting direction is defined as a reflective surface 21e (see FIG. 3).
[0025]
As shown in FIG. 5, each of the fitting surfaces 20 a and 15 a of the intermediate flow path forming unit 20 and the main body flow path cutting portion 15 of the main body unit 11 is formed on an inclined surface that is inclined along the fitting direction. Yes. Specifically, the upper and lower fitting surfaces 20a and 15a have a taper that is closer to the front side in the fitting direction with the linear intermediate flow path 21a interposed therebetween. The main body unit 10 (the main body 11 and the lid 17) and the intermediate flow path forming unit 20 are both made of an aluminum die-cast material ADC12 (JIS H5302; linear expansion coefficient 21 × 10 ⁻⁶ / K). In this way, by the taper formation of the fitting surfaces 20a, 15a and the same material configuration of the main body unit 10 and the intermediate flow path forming unit 20, when the intermediate flow path forming unit 20 and the main body flow path cutting portion 15 are fitted or It prevents slipping out during thermal expansion, and maintains airtightness between the main body channel cut portion 15 and the window hole 16.
[0026]
When the main body part 11 (main body flow path cutting part 15) and the intermediate flow path forming unit 20 are fitted, the intermediate flow path forming unit 20 is pressed and held by the lid part 17 from the rear side in the fitting direction, and the packing 17a. The lid portion 17 is fixed to the main body portion 11 by the (seal member) and the fixing screw 17b (fixing member). Since the main body part 11 (main body flow path cutting part 15) and the intermediate flow path forming unit 20 are securely fitted and the main body part 11 and the lid part 17 are fixed, the main body part 11, the lid part 17 and the intermediate flow part The airtightness of the three members of the path forming unit 20 is sufficiently maintained.
[0027]
As shown in FIG. 1, the output signals obtained by the transmission / reception units 23a and 23b (sensor elements) of the ultrasonic sensor 23 are transmitted to the flow rate calculation processing circuit 24 via lead wires 25 and 25 to calculate the gas flow rate. This is notified using a flow rate display (not shown) or the like. The transmission / reception units 23a and 23b, the flow rate calculation processing circuit 24, the lead wires 25 and 25, the flow rate display unit, and the like constitute a flow rate measurement unit M. Since the lead wires 25 and 25 are drawn out from the ultrasonic sensor 23 (transmission / reception units 23a and 23b) provided to protrude outside from the window holes 16 and 16, the measurement gas leaks to the outside through the core wire portion, and is airtight. Does not become insufficient or the measurement accuracy does not decrease. Thus, the airtightness of the three parts of the main body part 11, the lid part 17, and the intermediate flow path forming unit 20 is ensured, and the lead wires 25 and 25 are located outside the flow path. There will be no fire caused by sparks. Reference numeral 26 denotes a rectifying member that is provided between the inlet-side connecting flow path 21b and the linear intermediate flow path 21a, and suppresses the disturbance of the measurement gas flow in the flow path to equalize the velocity distribution ( (See FIG. 2).
[0028]
Therefore, in order to assemble such an ultrasonic flowmeter 100, the intermediate flow path forming unit 20 is fitted to the main body flow path cutting section 15 of the main body section 11 while matching the fitting surfaces 15a and 20a. And the protrusion parts 22 and 22 of the intermediate flow path formation unit 20 are protruded outside from the window holes 16 and 16 of the main-body part 11. FIG. The intermediate flow path forming unit 20 is pressed from the rear side in the fitting direction toward the main body 11 by the lid 17, and the lid 17 is fixed to the main body 11 by the fixing screw 17 b with the packing 17 a interposed therebetween.
[0029]
In order to remove (replace) the transmission / reception units 23a and 23b due to the deterioration of the sound pressure sensitivity characteristic due to the temporal change of the ultrasonic sensor, or the recycling of the ultrasonic flowmeter or the inspection failure during assembly, the transmission / reception units 23a and 23b The mounting screws 23c, 23c and the pressing plate may be removed.
[0030]
(Example 2)
Next, another embodiment of the ultrasonic flowmeter will be described. An ultrasonic flowmeter 200 shown as the second embodiment is shown in FIG. 6 as a cross-sectional view taken along line AA in FIG. 3 (first embodiment), and in FIG. 7 as a B- in FIG. 5 (first embodiment). It is represented by a B cross-sectional view. The ultrasonic flowmeter 200 is also composed of a main body unit 10, an intermediate flow path forming unit 20, and a shutoff valve 30, and the main body unit 10 includes a main body portion 11 and a lid portion 17.
[0031]
In FIG. 6, the ultrasonic flowmeter 200 is different from the ultrasonic flowmeter 100 (Example 1) as follows. That is, in this embodiment, the window hole 16 is formed through the lid portion 17, and the main body channel cutout portion 15 communicates with the outside in the thickness direction of the lid portion 17. Therefore, the protruding portion 22 of the intermediate flow path forming unit 20 protrudes from the window hole 16 of the lid portion 17 to seal the window hole 16. The ultrasonic sensor 23 is configured in the following reflective V-shaped arrangement. That is, a pair of transmission / reception parts 23a, 23b is separated from the wall surface (attachment surface) 21d forming the short side on the rear side in the fitting direction in the cross section orthogonal to the flow direction of the straight intermediate flow path 21a by a predetermined distance W in the flow direction. A wall surface that is attached and forms a short side on the front side in the fitting direction is defined as a reflecting surface 21e. In addition, in order to insert the shut-off valve 30 in the lid part 17, an insertion hole penetratingly formed in the thickness direction is also formed, but the illustration is omitted.
[0032]
(Modification)
In the above embodiment, the case where the reflection type V-shaped arrangement is adopted as the arrangement of the ultrasonic sensor (transmission / reception unit) and the path through which the ultrasonic wave passes (referred to as a survey line) has been described. In the reflective V-shaped arrangement, the pair of transmission / reception units can be concentrated on the same side along the flow direction, so that there is an advantage that the transmission / reception units can be attached and detached from the same direction. In addition to the reflective V-shaped array, many types are known for the line measuring method of the ultrasonic sensor (transmission / reception unit) in the ultrasonic flowmeter. Examples of application of the present invention to other line survey methods will be described below.
[0033]
(1) Transmission-type bypass arrangement (FIG. 8 (a))
A bypass part 122 is integrally formed on the front side in the fitting direction, and a transmission type ultrasonic sensor 123 (transmission / reception parts 123a and 123b) for measuring a gas flow rate is detachably attached to the bypass part 122. As in the case of the reflective V-shaped arrangement, the pair of transmission / reception units 123a and 123b can be concentrated on the same side in the flow direction.
[0034]
(2) Transmission type V-shaped array (FIG. 8B)
In this method, ultrasonic waves emitted from one transmitter 223a are received by a pair of receivers 223b and 223b arranged at a predetermined distance in the flow direction. In this method, the transmission unit 223a and the reception units 223b and 223b are arranged separately on both sides in the flow direction.
[0035]
(3) Crossed X array (FIG. 8 (c))
The ultrasonic waves emitted from the pair of transmitters 323a and 323a arranged at a predetermined distance along the flow direction are received by the pair of receivers 323b and 323b arranged at a predetermined distance along the flow direction. It is a method. This system corresponds to the system shown in FIG. 8 (b) in which one transmitter is added as a pair.
[0036]
In the above embodiments and modifications, only the case where the main unit 10 includes the main body 11 having the main body flow path 14 and the lid 17 that covers the main body 11 from the outside has been described. The unit 10 may have the following configuration. In other words, the main body unit may be configured such that the first main body portion and the second main body portion each having a half-shaped main body flow path are combined. However, in this case, the window hole is provided in at least one of the first main body and the second main body, and the lid may or may not be provided.
[Brief description of the drawings]
FIG. 1 is an overall perspective view of an embodiment of an ultrasonic flowmeter according to the present invention.
FIG. 2 is a front sectional view of FIG.
3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a perspective view of an intermediate flow path forming unit.
5 is a cross-sectional view taken along line BB in FIG.
6 is a cross-sectional view of another embodiment of the ultrasonic flowmeter according to the present invention, taken along line AA in FIG.
7 is a cross-sectional view taken along the line BB in place of FIG.
FIG. 8 is an explanatory diagram showing a modification of the ultrasonic flowmeter according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Main body unit 11 Main body part 12 Inlet 13 Outlet 14 Main body flow path 15 Main body flow path cutting part 15a Fitting surface 16 Window hole 17 Cover part 20 Intermediate flow path forming unit 20a Fitting surface 21 Intermediate flow path 22 Protruding part 23 Ultrasonic sensor 23a, 23b Transmission / reception unit 30 Shut-off valve 100, 200 Ultrasonic flow meter

Claims

A main body unit in which a main body channel for allowing fluid to pass between an inlet and an outlet opening on the outer surface is formed, and
An intermediate flow path that is connected to the main body flow path when the main body flow path cutting portion formed in the main body unit is fitted from the direction intersecting the fluid flow direction is formed through the inner flow path. A protrusion is formed on the front side in the fitting direction in correspondence with the window hole that opens to the outer surface of the main body unit and communicates with the path cutting portion, and measures the flow rate of the fluid that passes through the intermediate flow path at the protrusion. An intermediate flow path forming unit to which an ultrasonic sensor for detachable attachment is attached,
By fitting the intermediate flow path forming unit into the main body unit so that the intermediate flow path communicates with the main body flow path, the projecting portion protrudes outside from the window hole of the main body unit, thereby opening the window hole. An ultrasonic flowmeter, wherein the ultrasonic sensor is hermetically sealed and the ultrasonic sensor is detachable from the outside.

A main body part in which a main body channel for allowing a fluid to pass between an inlet and an outlet opening on the outer surface is formed inside, and a lid part for covering the main body channel cutting part formed in the main body part from the outside A main unit having
An intermediate flow path connected to the main body flow path when the main body flow path cutting section of the main body section is fitted from a direction intersecting with the fluid flow direction is formed through the body flow path cutting section. A protrusion is formed on the front side in the fitting direction in correspondence with the window hole opened on the outer surface of the main body, and the protrusion is used to measure the flow rate of the fluid passing through the intermediate flow path. An intermediate flow path forming unit to which a sonic sensor is detachably attached,
By fitting the intermediate flow path forming unit to the main body so that the intermediate flow path communicates with the main body flow path, the protruding portion protrudes outside from the window hole of the main body portion, and the window hole is formed. An ultrasonic flowmeter, wherein the ultrasonic sensor is hermetically sealed and the ultrasonic sensor is detachable from the outside.

At least a portion of the intermediate flow path formed in the intermediate flow path forming unit is formed in a straight line, and the straight intermediate flow path is connected to the main body flow path cutting portion in a cross section orthogonal to the fluid flow direction. While formed in a rectangular shape with the long side in the fitting direction,
In the ultrasonic sensor, a pair of transmission / reception units are attached to a wall surface forming a short side on the front side in the fitting direction in a cross-section orthogonal to the flow direction of the linear intermediate flow path at a predetermined distance in the flow direction, and The ultrasonic flow rate according to claim 2, wherein the ultrasonic flow rate is configured in a reflective V-shaped array with a wall surface forming a short side on the rear side in the fitting direction as a reflecting surface, and the transmitting / receiving unit is individually removable from the outside. Total.

A main body part in which a main body channel for allowing a fluid to pass between an inlet and an outlet opening on the outer surface is formed inside, and a lid part for covering the main body channel cutting part formed in the main body part from the outside A main unit having
An intermediate flow path connected to the main body flow path when the main body flow path cutting portion of the main body section is fitted from a direction intersecting the fluid flow direction is formed through the inside, and the thickness of the lid portion A projection is formed on the rear side in the fitting direction corresponding to the window hole formed through the lid so that the main body channel cutout portion communicates with the outside in the direction, and the intermediate channel is formed in the projection. An intermediate flow path forming unit to which an ultrasonic sensor for measuring the flow rate of the fluid passing through is detachably attached,
By fitting the intermediate flow path forming unit to the main body so that the intermediate flow path communicates with the main body flow path, the protruding portion protrudes outside from the window hole of the lid portion, thereby opening the window hole. An ultrasonic flowmeter, wherein the ultrasonic sensor is hermetically sealed and the ultrasonic sensor is detachable from the outside.

At least a portion of the intermediate flow path formed in the intermediate flow path forming unit is formed in a straight line, and the straight intermediate flow path is connected to the main body flow path cutting portion in a cross section orthogonal to the fluid flow direction. While formed in a rectangular shape with the long side in the fitting direction,
In the ultrasonic sensor, a pair of transmission / reception units are attached to a wall surface forming a short side on the rear side in the fitting direction in a cross-section orthogonal to the flow direction of the linear intermediate flow path at a predetermined distance in the flow direction, and 5. The ultrasonic flow rate according to claim 4, wherein the ultrasonic flow rate is configured in a reflective V-shaped array in which a wall surface forming a short side on the front side in the fitting direction is a reflective surface, and the transmission / reception unit is individually removable from the outside. Total.

The inflow port and the outflow port are respectively opened on the upper surface of the main body having a rectangular parallelepiped shape, and the intermediate flow path forming unit is cut from the main body flow path of the main body from a direction substantially perpendicular to the fluid flow direction. By fitting to the part,
The ultrasonic flowmeter according to claim 2, wherein the linear intermediate flow path is substantially orthogonal to the main body flow path and is disposed along a lower surface of the main body portion.

The said cover part is fixed to the main-body part in the state which pressed and hold | maintained the said intermediate flow path formation unit fitted to the said main-body part from the fitting direction back side. The described ultrasonic flowmeter.

The fitting surface of the said intermediate | middle flow path formation unit and the main body flow path cutting part of the said main body unit is formed in the inclined surface which inclines along the said fitting direction. Ultrasonic flow meter.

The ultrasonic flowmeter according to any one of claims 1 to 8, wherein at least the intermediate flow path forming unit and the main body flow path cutting portion of the main body unit are made of a material having the same or similar thermal expansion coefficient. .