JPH04315917A - Electromagnetic flow meter detector - Google Patents

Abstract

PURPOSE:To reduce the measuring error owing to the difference of material of the external piping of an electromagnetic flow meter detector. CONSTITUTION:The length of the part where a yoke 2 in an electromagnetic flow meter detector is contacted to a measuring pipe 4 in the pipe axial direction is made shorter than the length of a casing in the pipe axial direction. As a result, a leaking magnetic flux out of the flow meter is reduced, the magnetic flux distribution in the flow meter is not changed by the material of the external piping and a measuring error owing to the difference of material of the external piping can be reduced.

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、プラントや水処理設備
などにおける流量の管理・制御に好適な電磁流量計検出
器に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic flow meter detector suitable for managing and controlling flow rates in plants, water treatment facilities, and the like.

【０００２】0002

【従来の技術】従来の電磁流量計は特開昭５８−６４１
１号公報に記載されているように、流体を通す測定管と
、測定管の半径方向に磁界を発生する磁極に巻かれた励
磁コイルの上下一組をもつ磁界発生装置と、磁界方向お
よび測定管軸方向のそれぞれに直交する一直線上に位置
して測定管に設けられた一対の電極と、全体を固定する
ケーシングとから構成され、励磁コイルと外部配管の間
には、非磁性体のケーシングしか設けていなかった。[Prior art] A conventional electromagnetic flowmeter is disclosed in Japanese Patent Application Laid-Open No. 58-641.
As described in Publication No. 1, a magnetic field generating device has a measuring tube through which a fluid passes, a set of upper and lower excitation coils wound around magnetic poles that generate a magnetic field in the radial direction of the measuring tube, and It consists of a pair of electrodes installed on the measuring tube in a straight line orthogonal to each tube axis direction, and a casing that fixes the whole.A non-magnetic casing is placed between the excitation coil and the external piping. There was only one set up.

【０００３】また、励磁コイルと外部配管との間にヨー
クを設けた場合でも、ヨークが測定管に接する部分の管
軸方向長さは、ケーシングの管軸方向長さとほぼ等しく
なっていた。[0003] Even when a yoke is provided between the excitation coil and the external piping, the length of the portion of the yoke in contact with the measuring tube in the tube axis direction is approximately equal to the length of the casing in the tube axis direction.

【０００４】0004

【発明が解決しようとする課題】上記従来技術では、励
磁コイルと外部配管との間には非磁性体のケーシングし
かないか、または、ヨークが測定管に接する部分の管軸
方向長さがケーシングの管軸方向長さとほぼ等しいため
、流量計外部への漏洩磁束が大きく、外部配管の材質が
磁性体の場合と、非磁性体の場合とで、流量計内部の磁
界分布が変ってしまい、同じ流量を測定しても、異なっ
た流量信号値が出力されるという欠点があった。[Problems to be Solved by the Invention] In the above-mentioned prior art, either there is only a non-magnetic casing between the excitation coil and the external piping, or the length in the tube axis direction of the portion where the yoke contacts the measuring tube is longer than the casing. Since the length in the axial direction of the pipe is almost equal to that of the flowmeter, the leakage magnetic flux to the outside of the flowmeter is large, and the magnetic field distribution inside the flowmeter changes depending on whether the external piping is made of magnetic or non-magnetic material. There is a drawback that different flow signal values are output even if the same flow rate is measured.

【０００５】本発明の目的は、流量計外部への漏洩磁束
を少なくし、外部配管材質の違いによる測定誤差を小さ
くすることにある。An object of the present invention is to reduce leakage magnetic flux to the outside of a flowmeter and to reduce measurement errors due to differences in external piping materials.

【０００６】[0006]

【課題を解決するための手段】上記目的を達成するため
、本発明は流体を通す測定管と、磁極に巻かれた上下一
組の励磁コイルおよび上下の励磁コイルを接続し前記測
定管と励磁コイルを囲むように取り付けたヨークを設け
、前記測定管の半径方向に磁界を発生する磁界発生装置
と、前記磁界方向および前記測定管の管軸方向のそれぞ
れに直交する一直線上に位置して前記測定管に取付けら
れた一対の電極と、全体を固定するケーシングとを備え
る電磁流量計検出器において、前記ヨークが前記測定管
に接する部分の管軸方向長さをケーシングの管軸方向長
さよりも短くすることを特徴とする。[Means for Solving the Problems] In order to achieve the above object, the present invention connects a measurement tube through which a fluid passes, a set of upper and lower excitation coils wound around magnetic poles, and an excitation coil connected to the measurement tube. a magnetic field generating device including a yoke attached to surround the coil and generating a magnetic field in the radial direction of the measuring tube; In an electromagnetic flowmeter detector comprising a pair of electrodes attached to a measuring tube and a casing that fixes the entire body, the length of the portion where the yoke contacts the measuring tube in the tube axis direction is longer than the length of the casing in the tube axis direction. Characterized by being short.

【０００７】[0007]

【作用】ヨークが測定管に接する部分の管軸方向長さを
ケーシングの管軸方向長さより短くすることにより、流
量計内の磁束は、ヨークの間の部分に集中し、軸方向に
拡がりの少ない二次元的な磁界分布となり、流量計外部
への漏洩磁束は少なくなる。[Function] By making the axial length of the part where the yoke touches the measurement pipe shorter than the casing's axial length, the magnetic flux inside the flowmeter is concentrated in the part between the yokes, and spreads out in the axial direction. This results in a less two-dimensional magnetic field distribution, and less magnetic flux leaks to the outside of the flowmeter.

【０００８】流量計外部への漏洩磁束が少なければ、外
部配管の材質が磁性体の場合と、非磁性体の場合とで、
流量計内部の磁界分布の差が小さくなり、同じ流量を測
定したときの流量出力信号値の差は小さくなる。従って
、外部配管の材質の違いによる誤差を小さくすることが
できる。[0008] If the leakage magnetic flux to the outside of the flowmeter is small, the difference will be
The difference in magnetic field distribution inside the flowmeter becomes smaller, and the difference in flow rate output signal values when measuring the same flow rate becomes smaller. Therefore, errors caused by differences in the material of the external piping can be reduced.

【０００９】[0009]

【実施例】以下、本発明の一実施例を図１，図２、およ
び図３により説明する。Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

【００１０】本発明による電磁流量計検出器は、内面に
絶縁性ライニングを施し一対の電極５を取り付けてある
測定管４と、磁極７ａ，７ｂに巻かれた上下一組の励磁
コイル３ａ，３ｂならびに上下の励磁コイル３ａ，３ｂ
を接続し測定管４と励磁コイル３を囲むように取り付け
たヨーク２をもち、測定管４の半径方向に磁界を発生す
る磁界発生装置と、全体を固定するケーシング１からな
る。The electromagnetic flowmeter detector according to the present invention comprises a measuring tube 4 having an insulating lining on its inner surface and a pair of electrodes 5 attached thereto, and a pair of upper and lower excitation coils 3a, 3b wound around magnetic poles 7a, 7b. and upper and lower excitation coils 3a, 3b
It has a yoke 2 connected to the measurement tube 4 and attached so as to surround the excitation coil 3, a magnetic field generating device that generates a magnetic field in the radial direction of the measurement tube 4, and a casing 1 that fixes the whole.

【００１１】図１に示すように、ヨーク２が測定管４に
接する部分の管軸方向長さは、ケーシング１の管軸方向
長さよりも短くなっており、ヨーク２が励磁コイル３を
囲むような形状になっている。図２は従来の電磁流量計
検出器を示す構造図で、ヨーク２が測定管４に接する部
分の管軸方向長さは、ケーシング１の管軸方向長さとほ
ぼ等しくなっている。図３は、流量計内部の磁界分布を
表している。従来の電磁流量計検出器の場合、外部配管
位置における磁束密度の値が大きく漏洩磁束が大きいの
に対し、本発明による電磁流量計検出器の場合、外部配
管位置での磁束密度の値はほぼ０になっており、漏洩磁
束が非常に少ないことがわかる。As shown in FIG. 1, the length of the portion where the yoke 2 contacts the measurement tube 4 in the tube axis direction is shorter than the length of the casing 1 in the tube axis direction, so that the yoke 2 surrounds the excitation coil 3. It has a shape. FIG. 2 is a structural diagram showing a conventional electromagnetic flowmeter detector, and the length of the portion where the yoke 2 contacts the measuring tube 4 in the tube axis direction is approximately equal to the length of the casing 1 in the tube axis direction. FIG. 3 shows the magnetic field distribution inside the flowmeter. In the case of a conventional electromagnetic flowmeter detector, the magnetic flux density value at the external piping position is large and the leakage magnetic flux is large, whereas in the case of the electromagnetic flowmeter detector according to the present invention, the magnetic flux density value at the external piping position is approximately 0, indicating that the leakage magnetic flux is extremely small.

【００１２】図４は、本発明の第二の実施例で、ヨーク
２の形状が励磁コイル３を包み込むように角形となって
いる。このようなヨークの構造でも、図１に示す電磁流
量計検出器と同様の磁界分布となり、漏洩磁束を小さく
することができる。FIG. 4 shows a second embodiment of the present invention, in which the yoke 2 has a rectangular shape so as to wrap around the excitation coil 3. Even with such a yoke structure, the magnetic field distribution is similar to that of the electromagnetic flowmeter detector shown in FIG. 1, and leakage magnetic flux can be reduced.

【００１３】図５および図６は、本発明の第三および第
四の実施例である。図１および図２の実施例におけるヨ
ーク２の形状は複雑でコスト高になるのを改善し、図５
および図６に示す実施例では、ヨーク２と補助ヨーク８
に分けている。ただし、この場合、ヨーク２と補助ヨー
ク８の接触部分で磁気抵抗が発生するため、図１および
図２に示した実施例の磁気回路よりも多少性能がおちる
。FIGS. 5 and 6 show third and fourth embodiments of the present invention. The shape of the yoke 2 in the embodiments shown in FIGS. 1 and 2 has been improved from being complicated and costly.
And in the embodiment shown in FIG. 6, the yoke 2 and the auxiliary yoke 8
It is divided into However, in this case, since magnetic resistance occurs at the contact portion between the yoke 2 and the auxiliary yoke 8, the performance is somewhat lower than that of the magnetic circuit of the embodiment shown in FIGS. 1 and 2.

【００１４】[0014]

【発明の効果】本発明によれば、電磁流量計検出器外部
への漏洩磁束を小さくできるので、外部配管材質が磁性
体の場合の流量信号値と、非磁性体の場合の流量信号値
との差を小さくすることができる。すなわち、電磁流量
計の外部配管材質の違いによる測定誤差を低減すること
ができる。[Effects of the Invention] According to the present invention, the leakage magnetic flux to the outside of the electromagnetic flowmeter detector can be reduced, so that the flow signal value when the external piping material is magnetic and the flow signal value when the material is non-magnetic are different. The difference can be reduced. That is, measurement errors due to differences in the external piping materials of the electromagnetic flowmeter can be reduced.

【図面の簡単な説明】[Brief explanation of the drawing]

【図１】本発明による一実施例の断面図。FIG. 1 is a sectional view of an embodiment according to the present invention.

【図２】従来の電磁流量計検出器を示す断面図。FIG. 2 is a sectional view showing a conventional electromagnetic flowmeter detector.

【図３】本発明の効果を表す磁界分布の説明図。FIG. 3 is an explanatory diagram of magnetic field distribution showing the effects of the present invention.

【図４】本発明の第二の実施例の断面図。FIG. 4 is a sectional view of a second embodiment of the invention.

【図５】本発明の第三の実施例の断面図。FIG. 5 is a sectional view of a third embodiment of the invention.

【図６】本発明の第四の実施例の断面図。FIG. 6 is a sectional view of a fourth embodiment of the present invention.

【符号の説明】[Explanation of symbols]

１…ケーシング、２…ヨーク、３，３ａ，３ｂ…励磁コ
イル、４…測定管、５…電極、６…外部配管、７，７ａ
，７ｂ…磁極、８…補助ヨーク。DESCRIPTION OF SYMBOLS 1... Casing, 2... Yoke, 3, 3a, 3b... Excitation coil, 4... Measuring tube, 5... Electrode, 6... External piping, 7, 7a
, 7b... Magnetic pole, 8... Auxiliary yoke.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】流体を通す測定管と、磁極に巻かれた上，
下一組の励磁コイルおよび前記上下の励磁コイルを接続
し前記測定管と前記励磁コイルを囲むように取り付けた
ヨークを設け、前記測定管の半径方向に磁界を発生する
磁界発生装置と、前記磁界方向および前記測定管の管軸
方向のそれぞれに直交する一直線上に位置して前記測定
管に取付けられた一対の電極と、全体を固定するケーシ
ングとを備える電磁流量計検出器において、前記ヨーク
が前記測定管に接する部分の管軸方向長さを前記ケーシ
ングの管軸方向長さよりも短くしたことを特徴とする電
磁流量計検出器。Claim 1: A measuring tube through which a fluid passes, a top wound around a magnetic pole,
a magnetic field generating device that connects a lower set of excitation coils and the upper and lower excitation coils, and includes a yoke attached to surround the measurement tube and the excitation coil, and generates a magnetic field in the radial direction of the measurement tube; In the electromagnetic flowmeter detector, the electromagnetic flowmeter detector includes a pair of electrodes attached to the measurement tube and located on a straight line perpendicular to the direction of the measurement tube and the tube axis direction of the measurement tube, and a casing that fixes the whole. An electromagnetic flowmeter detector characterized in that the length of the portion in contact with the measurement tube in the tube axis direction is shorter than the length of the casing in the tube axis direction.