JPH07229774A - Electromagnetic flow meter and flow rate measuring method - Google Patents

Abstract

PURPOSE:To measure the flow rate without digging out an existing duct line. CONSTITUTION:To the front surface 1a along the bottom surface of a duct line 101, to the upper surface 1b, and to an electric insulating member 1 having the inclined surfaces 1c on the upstream side and the downstream side, a pair of electrodes 2, a pair of earthing electrodes 3, and an exciting coil are provided. A detector main body 100 is connected to a transformer 20 through a connector 102 and a cord 103. The detector main body 100 is provided to a standard passage having the diameter and the form the same as the existing duct line 101 tentatively, a standard fluid is let flow by converting the water level, and the function F of the relation Q=F (e) of the flow signal e and the standard flow rate Q is stored in the memory of an operation circuit 7. Then, the detector main body 100 is installed to the existing duct line 101, and the unknown flow rate Q' is operated and found depending on the flow signal e and the function F at the formula Q'=F (e).

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は下水道や、工場排水のよ
うに管路や開水路を通常非満水状態で自然流下する流体
の流量を測定するのに好適な電磁流量計とそれを用いた
流量計測方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic flowmeter suitable for measuring the flow rate of a fluid that naturally flows down a pipe or an open water channel, such as a sewer or a factory drain, usually in a non-filled state. Flow rate measurement method.

【０００２】[0002]

【従来の技術】この種の電磁流量計として特開平４−２
９５７２３号公報が公知である。この従来技術を図３
（ａ）（ｂ）に示す。この電磁流量計は水平設置状態で
の測定管１１の底部の内面に、管軸方向と直角且つ水平
な方向に頂稜１３ａが延在し、この頂稜の上流側及び下
流側が共に頂稜を含む傾斜面１３ｂになっている凸部１
３を設け、この凸部１３上にその長手方向所要距離をお
いて一対の電極１２を配置したものである。2. Description of the Related Art As an electromagnetic flowmeter of this kind, Japanese Patent Laid-Open No. 4-2 is known.
Japanese Patent No. 95723 is known. This conventional technique is shown in FIG.
Shown in (a) and (b). In this electromagnetic flowmeter, an apex 13a extends on the inner surface of the bottom of the measurement pipe 11 in a horizontal installation state in a direction perpendicular to the pipe axis and horizontal, and both the upstream and downstream sides of the apex form the apex. Convex portion 1 that is inclined surface 13b including
3 is provided, and the pair of electrodes 12 is disposed on the convex portion 13 with a required distance in the longitudinal direction.

【０００３】この電磁流量計は、微小な流れであって
も、凸部に沿って凸部を乗り越えて流れるため、常に液
体が凸部上の電極と接することになり、微小な流れでも
十分測定でき、不感帯域をほぼゼロにすることができ
る。This electromagnetic flowmeter flows over a convex portion along a convex portion even if it is a minute flow, so that the liquid is always in contact with the electrode on the convex portion, and even a minute flow is sufficiently measured. It is possible to reduce the dead band to almost zero.

【０００４】また、特開平５−２７３０１５号公報の電
磁流量計も公知である。この従来技術を図４と図５に示
す。この電磁流量計はいわゆるパーマー・ボウラスフリ
ュームと組合わせたもので、２１は測定管、２２はパー
マー・ボウラスフリューム、２３はフリューム部分に水
平方向に対向して設けた一対の電極、２４はフリューム
下のスペースに設けた励磁コイル、２５は電極に生じた
電圧ｅを増幅する増幅器、２６は増幅器２５の出力をデ
ィジタル信号に変換するＡ／Ｄ変換器、２７は演算回
路、２８は励磁コイル２４を励磁する励磁電源、２９は
測定や励磁に必要なタイミング信号を発生するタイミン
グ回路である。An electromagnetic flowmeter disclosed in Japanese Patent Laid-Open No. 5-273015 is also known. This prior art is shown in FIGS. This electromagnetic flowmeter is combined with a so-called Palmer-Bourras flume. Reference numeral 21 is a measuring tube, 22 is a Palmer-Bourras flume, 23 is a pair of electrodes horizontally opposed to the flume portion, and 24 is An exciting coil provided in the space below the flume, 25 an amplifier for amplifying the voltage e generated at the electrodes, 26 an A / D converter for converting the output of the amplifier 25 into a digital signal, 27 an arithmetic circuit, 28 an exciting coil An exciting power source for exciting 24, and a timing circuit 29 for generating a timing signal necessary for measurement and excitation.

【０００５】[0005]

【発明が解決しようとする課題】この種の電磁流量計の
用途は、既設管路の流量調査がほとんどで、流量調査に
使う期間は１か月〜６か月程度の短期間である。Most of the applications of this type of electromagnetic flowmeter are the flow rate survey of the existing pipeline, and the period used for the flow rate survey is a short period of about 1 to 6 months.

【０００６】ところが、前記従来の非満水状態での流量
を計測する電磁流量計は、検出器が測定管（管路）と一
体的に構成されているため、この従来の電磁流量計を用
いて既設管路の流量調査をするには、事実上既設管路の
一部を地中から掘り出して、流量調査用の検出器と置き
換える必要があり、極めて大がかりな工事になるという
問題点があった。However, in the conventional electromagnetic flow meter for measuring the flow rate in the non-full state, the detector is integrally formed with the measuring pipe (pipe line), so that the conventional electromagnetic flow meter is used. In order to investigate the flow rate of the existing pipeline, it was necessary to dig a part of the existing pipeline from the ground and replace it with a detector for the flow rate survey, which was a very large-scale work. .

【０００７】又、従来は、流量調査のための大がかりな
工事を避けて、マンホール内に調査用の流量計を取付け
ることもあったが、マンホール内のスペースをほとんど
ふさいでしまうため、点検口としてのマンホールの機能
が失われてしまうという問題点があり、制約が多かっ
た。Further, conventionally, a large-scale construction for a flow rate survey was avoided and a flow meter for a survey was sometimes installed in the manhole. However, since the space in the manhole is almost occupied, it is used as an inspection port. There was a problem that the manhole function of was lost, and there were many restrictions.

【０００８】そこで、本発明は、このような問題点を解
消し、既設管路における短期間の流量調査に用いる好適
な、取付工事の費用や手間が軽減できる電磁流量計と流
量計測方法を提供することを目的とする。Therefore, the present invention provides an electromagnetic flow meter and a flow rate measuring method which solves such a problem and is suitable for a short-term flow rate survey in an existing pipeline, which can reduce the cost and labor of the installation work. The purpose is to do.

【０００９】[0009]

【課題を解決するための手段】前記目的を達成するため
に、本発明の電磁流量計は、既設の管路（１０１、１０
１Ａ）に取り付けるべく、少なくともその一部が管路
（１０１、１０１Ａ）の底面に沿う第１の面（１ａ）を
下部に有し、上面（１ｂ）が第１の面（１ａ）の最下部
（１′ａ）より上方に離れた水平面で形成されるととも
に、上流側と下流側に傾斜面（１ｃ）を有する電気絶縁
性の部材（１）と、部材（１）の上端両側に設けた一対
の電極（２）と、部材（１）の電極（２）より上流側と
下流側とに設けた一対のアース電極（３）と、部材
（１）の中に配設された励磁コイル（４）とを具備した
検出器要部（１００、１００Ａ）と、電極（２）に誘起
した流量信号（ｅ）に基いて流量（Ｑ′）を演算する演
算回路（７）と、前記検出器要部（１００、１００Ａ）
を前記演算回路（７）を有する変換器（２００）に電気
的に接続する手段とを具備したことを特徴とする。In order to achieve the above-mentioned object, the electromagnetic flowmeter of the present invention comprises an existing pipe (101, 10).
1A), at least a part thereof has a first surface (1a) along the bottom surface of the conduit (101, 101A) in the lower portion, and an upper surface (1b) is the lowermost portion of the first surface (1a). The electrically insulating member (1) is formed on a horizontal plane separated from (1'a) and has an inclined surface (1c) on the upstream side and the downstream side, and is provided on both sides of the upper end of the member (1). A pair of electrodes (2), a pair of ground electrodes (3) provided on the upstream side and the downstream side of the electrode (2) of the member (1), and an exciting coil () disposed inside the member (1). 4), a detector main part (100, 100A), an arithmetic circuit (7) for calculating a flow rate (Q ') based on a flow rate signal (e) induced in the electrode (2), and the detector. Main part (100, 100A)
And means for electrically connecting the converter to the converter (200) having the arithmetic circuit (7).

【００１０】そして、本発明の流量計は、上記本発明の
電磁流量計の検出器要部（１００、１００Ａ）を、本来
取り付けるべき既設の管路（１０１、１０１Ａ）と同一
の口径・形状の基準水路に予め所定の姿勢で仮設して、
水位を変えて基準流体を流したときの流量信号（ｅ）と
基準流体の流量（Ｑ）との関数関係Ｑ＝Ｆ（ｅ）の関数
Ｆを実測して演算回路（７）のメモリに記憶し、次に基
準水路から検出器要部（１００、１００Ａ）を外して既
設の管路（１０１）に取り付けて、この管路（１０１）
を流れる未知の流量（Ｑ′）を流量信号（ｅ）と関数Ｆ
に基いて算出することを特徴とする。In the flowmeter of the present invention, the detector main part (100, 100A) of the electromagnetic flowmeter of the present invention has the same diameter and shape as the existing pipeline (101, 101A) to be originally installed. Temporarily installed in the reference waterway in a predetermined posture in advance,
Functional relationship between flow rate signal (e) and flow rate (Q) of reference fluid when the water level is changed and the reference fluid is flowed, and the function F of Q = F (e) is measured and stored in the memory of the arithmetic circuit (7). Then, remove the detector main part (100, 100A) from the reference water channel and attach it to the existing pipeline (101).
Unknown flow rate (Q ') flowing through the flow rate signal (e) and the function F
It is characterized in that it is calculated based on.

【００１１】[0011]

【作用】電磁流量計の検出器要部（１００、１００Ａ）
を基準流路に所定の姿勢で予め仮設し、水位を変えて基
準流体を流し、そのときの流量信号（ｅ）と基準流体の
流量（Ｑ）との関数関係Ｑ＝Ｆ（ｅ）の関数Ｆを実測し
て演算回路（７）のメモリに記憶する。[Function] Detector main part of electromagnetic flowmeter (100, 100A)
Is preliminarily installed in the reference flow path in a predetermined posture and the reference fluid is flowed by changing the water level, and the functional relationship between the flow rate signal (e) and the flow rate (Q) of the reference fluid at that time is a function of Q = F (e) F is measured and stored in the memory of the arithmetic circuit (7).

【００１２】次に、検出器要部（１００、１００Ａ）を
基準水路から外して、既設の管路（１０１、１０１Ａ）
に取り付けて、この管路を流れる未知の流量（Ｑ′）
を、流量信号（ｅ）と関数Ｆに基いてＱ′＝Ｆ（ｅ）で
演算して求める。Next, the main part of the detector (100, 100A) is removed from the reference water channel and the existing pipeline (101, 101A) is removed.
Attached to the unknown flow rate (Q ') flowing through this pipe
Is calculated by Q '= F (e) based on the flow rate signal (e) and the function F.

【００１３】[0013]

【実施例】図１は本発明の第１実施例で、電気絶縁性の
部材１と、部材１の上端両側に設けた一対の電極２と、
部材１の電極２より上流側と下流側に設けた一対のアー
ス電極３と、部材１の中に配設した励磁コイル４とで検
出器要部１００を構成している。1 is a first embodiment of the present invention, which is an electrically insulating member 1, and a pair of electrodes 2 provided on both sides of the upper end of the member 1.
A pair of ground electrodes 3 provided on the upstream side and the downstream side of the electrode 2 of the member 1 and the exciting coil 4 arranged in the member 1 constitute a detector main part 100.

【００１４】部材１は検出器要部１００を既設の管路１
０１に取付けたときに、少なくともその一部が管路１０
１の底面に沿う第１の面１ａを下面に有し、上面１ｂが
第１の面１ａの最下部１′ａより上方に離れた水平面で
形成されるとともに、上流側と下流側に、流体が部材１
を乗り越えて流れるような向きに傾斜した傾斜面１ｃを
有する。The member 1 includes the detector main part 100 and the existing pipeline 1
01, when at least a part of the pipe 10
1 has a lower surface having a first surface 1a along the bottom surface, and an upper surface 1b is formed by a horizontal surface separated from the lowermost portion 1'a of the first surface 1a, and the upper surface 1b is formed on the upstream side and the downstream side. Is member 1
It has an inclined surface 1c that is inclined in such a direction that it can flow over and over.

【００１５】１０２は検出器要部１００の電極２、アー
ス電極３及び励磁コイル４を後述する変換器２００に電
気的にコード１０３で接続するためのコネクタで、下流
側の傾斜面１ｃのくぼみに着脱可能に設けてある。Reference numeral 102 denotes a connector for electrically connecting the electrode 2, the ground electrode 3 and the exciting coil 4 of the detector main part 100 to a converter 200 described later by a cord 103, which is provided in the recess of the inclined surface 1c on the downstream side. Detachable.

【００１６】検出器要部１００は、コード１０３によ
り、変換器２００と図１（ｄ）のように電気的に接続し
て使用するが、既設の管路１０１に取付ける前に、既設
の管路１０１と同一の口径・形状の基準流路に予め所定
の姿勢で仮設して、水位を変えて基準流体を流し、その
ときの流量信号ｅと基準流体の流量Ｑとの関数関係Ｑ＝
Ｆ（ｅ）の関数Ｆを実測して変換器２００の演算回路７
のメモリに予め記憶しておく。演算回路７はマイクロコ
ンピュータで構成されている。The detector main part 100 is used by being electrically connected to the converter 200 by a cord 103 as shown in FIG. 1 (d), but before being attached to the existing pipe line 101, the existing pipe line is installed. 101 is temporarily installed in a reference flow path having the same diameter and shape as that of 101 in advance in a predetermined posture, the reference fluid is caused to flow by changing the water level, and the functional relationship Q = the flow rate signal e and the reference fluid flow rate Q =
The function F of F (e) is actually measured and the arithmetic circuit 7 of the converter 200 is measured.
It is stored in advance in the memory. The arithmetic circuit 7 is composed of a microcomputer.

【００１７】５は流量信号を増幅する増幅器、６は増幅
器５の出力をディジタル信号に変換するＡ／Ｄ変換器、
７は演算回路、８は出力回路、９は励磁コイル４を励磁
する励磁電源、１０はＡ／Ｄ変換器６、演算回路７及び
励磁電源９等のタイミングを制御するタイミング回路で
ある。Reference numeral 5 is an amplifier for amplifying the flow rate signal, 6 is an A / D converter for converting the output of the amplifier 5 into a digital signal,
Reference numeral 7 is an arithmetic circuit, 8 is an output circuit, 9 is an exciting power source for exciting the exciting coil 4, and 10 is a timing circuit for controlling the timing of the A / D converter 6, the arithmetic circuit 7, the exciting power source 9, and the like.

【００１８】次に検出器要部１００を基準流路から外し
て、既設の管路１０１に取付ける。取付けは接着剤で部
材１や電極２を管路１０１の内壁に接着して固定する。
そして、管路１０１を流れる未知の流量Ｑ′を、電極２
に誘起する流量信号ｅと、演算回路７に記憶した関数Ｆ
とに基いてＱ′＝Ｆ（ｅ）の関係から演算して求める。
演算結果は出力回路８でディジタル表示用のディジタル
信号や、４〜２０ｍＡ出力などに加工して出力される。Next, the detector main part 100 is removed from the reference channel and attached to the existing pipeline 101. For attachment, the member 1 and the electrode 2 are adhered and fixed to the inner wall of the conduit 101 with an adhesive.
Then, the unknown flow rate Q ′ flowing through the pipe line 101 is changed to the electrode 2
Flow rate signal e induced to the function F and the function F stored in the arithmetic circuit 7.
And is calculated from the relationship of Q ′ = F (e) based on
The calculation result is processed by the output circuit 8 into a digital signal for digital display, a 4 to 20 mA output, etc., and output.

【００１９】図１（ｃ）は、既設の管路１０１に検出器
要部１００を接着固定した状態を示すが、検出器要部１
００を管路１０１に固定するには、他の方法によっても
よい。FIG. 1C shows a state in which the detector main part 100 is adhesively fixed to the existing pipeline 101.
00 may be fixed to the conduit 101 by another method.

【００２０】例えば、アース電極３の両端を上方へ円弧
状に延長し、円弧状部分の自由時の曲率半径を管路１０
１の内径の半径よりも大きく形成しておき、このアース
電極を管路１０１の内壁につっ張らせて固定することも
できる。For example, both ends of the ground electrode 3 are extended upward in an arc shape, and the radius of curvature of the arc-shaped portion when free is in the conduit 10.
It is also possible to make it larger than the radius of the inner diameter of 1 and to fix this earth electrode by stretching it on the inner wall of the pipe line 101.

【００２１】又、このように円弧状に形成したアース電
極に取付用ボルトを螺着し、このボルトの先端を管路１
０１の内壁に押し当てるようにしても良い。なお、この
ように検出器要部１００を既設管路１０１に取付けるに
は、下水道のマンホールや、排出口、流入口などから管
内に挿入して設置する。Further, a mounting bolt is screwed on the earth electrode thus formed in an arc shape, and the tip of the bolt is attached to the conduit 1
It may be pressed against the inner wall of 01. In addition, in order to attach the detector main part 100 to the existing pipeline 101 in this way, it is installed by inserting it into the pipe through a sewer manhole, a discharge port, an inflow port, or the like.

【００２２】図２は本発明の第２実施例で、第１実施例
のような円形管路でなく、矩形の管路１０１Ａに使用す
るのに好適な検出器要部１００Ａを示す。FIG. 2 shows a second embodiment of the present invention, which shows a detector main part 100A suitable for use in a rectangular conduit 101A instead of the circular conduit as in the first embodiment.

【００２３】[0023]

【発明の効果】本発明の電磁流量計と、流量計測方法は
上述のように構成されているので、検出器要部（１０
０、１００Ａ）がコンパクトで軽量であって、測定管が
要らないため、安価で、既設管路への設置が容易であ
る。Since the electromagnetic flowmeter and the flow rate measuring method of the present invention are configured as described above, the detector main part (10
(0, 100A) is compact and lightweight and does not require a measuring tube, so it is inexpensive and easy to install in an existing pipeline.

【００２４】また、マンホール内に取付けないため、マ
ンホールの点検口としての機能をそこなうこともなく、
設置が容易なため、いろいろな場所に取付けられ、設置
の自由度が増す利点がある。Since it is not installed in the manhole, it does not impair the function of the inspection hole of the manhole.
Since it is easy to install, it has the advantage of being installed in various places and increasing the degree of freedom of installation.

【００２５】又、コード（１０３）をコネクタ（１０
２）で検出器要部（１００、１００Ａ）の下流側傾斜面
（１ｃ）に着脱可能に設けたため、管路への検出器要部
の取付取外しが容易となり、且つ流量計測への悪影響が
少なくなる。The cord (103) is attached to the connector (10
Since it is detachably provided on the downstream inclined surface (1c) of the main part of the detector (100, 100A) in 2), the main part of the detector can be easily attached to and detached from the pipeline, and the adverse effect on the flow rate measurement is small. Become.

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

【図１】本発明の第１実施例で、（ａ）は検出器要部の
斜視図、（ｂ）は検出器要部の縦断面側面図、（ｃ）は
検出器要部を既設管路へ取付けた状態を上流方向からみ
た図、（ｄ）は電磁流量計の系統図である。FIG. 1 is a first embodiment of the present invention, in which (a) is a perspective view of an essential part of the detector, (b) is a vertical cross-sectional side view of the essential part of the detector, and (c) is an existing pipe with the essential part of the detector. The figure which looked at the state attached to the path from the upstream direction, (d) is a system diagram of an electromagnetic flowmeter.

【図２】本発明の第２実施例で、（ａ）は検出器要部の
斜視図、（ｂ）は検出器要部を既設管路へ取付けた状態
を上流方向からみた図である。FIG. 2A is a perspective view of a main part of a detector according to the second embodiment of the present invention, and FIG. 2B is a view of a state in which the main part of the detector is attached to an existing pipeline as viewed from the upstream direction.

【図３】従来技術の一例の測定管を示し、（ａ）は横断
面図、（ｂ）は縦断面図である。3A and 3B show an example of a conventional measuring tube, FIG. 3A is a horizontal sectional view, and FIG. 3B is a vertical sectional view.

【図４】他の従来技術の系統図で、検出器は図５のＡ−
Ａ断面を示す。4 is a system diagram of another prior art, in which the detector is A- of FIG.
The A section is shown.

【図５】図４の従来技術の検出器の縦断面略図である。5 is a schematic longitudinal cross-section of the prior art detector of FIG.

【符号の説明】[Explanation of symbols]

１ 部材 １ａ 第１の面 １′ａ 最下部 １ｂ 上面 １ｃ 傾斜面 ２ 電極 ３ アース電極 ４ 励磁コイル ７ 演算回路 １００、１００Ａ 検出器要部 １０１、１０１Ａ 既設管路 １０２ コネクタ ２００ 変換器 ｅ 流量信号 Ｑ 基準流量 Ｑ′ 未知の流量 Ｆ 関数 1 member 1a 1st surface 1'a lowest part 1b upper surface 1c inclined surface 2 electrode 3 earth electrode 4 exciting coil 7 arithmetic circuit 100, 100A detector main part 101, 101A existing pipeline 102 connector 200 converter e flow signal Q Reference flow rate Q'Unknown flow rate F function

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 既設の管路（１０１、１０１Ａ）に取り
付けるべく、少なくともその一部が管路（１０１、１０
１Ａ）の底面に沿う第１の面（１ａ）を下部に有し、上
面（１ｂ）が第１の面（１ａ）の最下部（１′ａ）より
上方に離れた水平面で形成されるとともに、上流側と下
流側に傾斜面（１ｃ）を有する電気絶縁性の部材（１）
と、部材（１）の上端両側に設けた一対の電極（２）
と、部材（１）の電極（２）より上流側と下流側とに設
けた一対のアース電極（３）と、部材（１）の中に配設
された励磁コイル（４）とを具備した検出器要部（１０
０、１００Ａ）と、 電極（２）に誘起した流量信号（ｅ）に基いて流量
（Ｑ′）を演算する演算回路（７）と、 前記検出器要部（１００、１００Ａ）を前記演算回路
（７）を有する変換器（２００）に電気的に接続する手
段とを具備したことを特徴とする電磁流量計。1. At least a part of the pipeline (101, 101A) is attached to the existing pipeline (101, 101A).
1A) has a first surface (1a) along a bottom surface thereof at a lower portion, and an upper surface (1b) is formed as a horizontal plane apart from a lowermost portion (1'a) of the first surface (1a). , An electrically insulating member (1) having inclined surfaces (1c) on the upstream side and the downstream side
And a pair of electrodes (2) provided on both sides of the upper end of the member (1)
And a pair of ground electrodes (3) provided upstream and downstream of the electrode (2) of the member (1), and an exciting coil (4) arranged in the member (1). Detector main part (10
0, 100A), an arithmetic circuit (7) for calculating the flow rate (Q ′) based on the flow rate signal (e) induced in the electrode (2), and the detector main part (100, 100A) An electromagnetic flowmeter, characterized in that it comprises means for electrically connecting to the converter (200) having (7). 【請求項２】 請求項１の電気的に接続する手段が前記
傾斜面（１ｃ）のうち下流側の傾斜面に設けたくぼみ部
に抜取可能装着したコネクタ（１０２）であることを特
徴とする電磁流量計。2. The electrically connecting means according to claim 1, characterized in that it is a connector (102) detachably attached to a recess provided on a downstream side inclined surface of the inclined surface (1c). Electromagnetic flow meter. 【請求項３】 請求項１の電磁流量計の検出器要部（１
００、１００Ａ）を、本来取り付けるべき既設の管路
（１０１、１０１Ａ）と同一の口径・形状の基準水路に
予め所定の姿勢で仮設して、水位を変えて基準流体を流
したときの流量信号（ｅ）と基準流体の流量（Ｑ）との
関数関係Ｑ＝Ｆ（ｅ）の関数Ｆを実測して演算回路
（７）のメモリに記憶し、 次に基準水路から検出器要部（１００、１００Ａ）を外
して既設の管路（１０１）に取り付けて、この管路（１
０１）を流れる未知の流量（Ｑ′）を流量信号（ｅ）と
関数Ｆに基いて算出することを特徴とする流量計測方
法。3. A detector main part (1) of the electromagnetic flow meter according to claim 1.
00, 100A) is temporarily installed in a predetermined posture in a reference channel having the same diameter and shape as the existing pipeline (101, 101A) to be originally installed, and the flow signal when the reference fluid is flowed while changing the water level. The function F of the functional relationship Q = F (e) between (e) and the flow rate (Q) of the reference fluid is actually measured and stored in the memory of the arithmetic circuit (7). , 100A) and attach it to the existing pipeline (101),
01) The unknown flow rate (Q ') flowing through the flow rate signal (e) and the function F are calculated based on the function F.