JPS59584Y2 - Denjiri Yuryokei - Google Patents

Description

【考案の詳細な説明】 本考案は外筐が成層鉄心の機能を兼ねる。[Detailed explanation of the idea] In this invention, the outer casing also functions as a stratified iron core.

電磁流量計に関する。Regarding electromagnetic flowmeters.

今日、プラント工業等において流体流量測定用として広
く用いられる電磁流量計は導管を流れる被測定流体の流
れ方向に対して直角な方向に磁界を加え１、磁界と流体
の流速との作用により流体中に生じた流速に比例する起
電力をこの磁界方向に対し直角方向に設けられた電極か
らとりだして、この起電力から導管における流量の流量
を測定するものである。Today, electromagnetic flowmeters, which are widely used in the plant industry to measure fluid flow rates, apply a magnetic field in a direction perpendicular to the flow direction of the fluid to be measured flowing through a conduit (1). An electromotive force proportional to the flow velocity generated in the magnetic field is taken out from an electrode provided perpendicular to the direction of the magnetic field, and the flow rate in the conduit is measured from this electromotive force.

この電磁流量計においては流体の流れ方向に対し直角な
方向の磁界分布を均一にすることが流量測定するうえで
好ましい要件であり、コイルおよび成層鉄心の作用によ
り電極を含む導管内を均一磁界分布にしている。In this electromagnetic flowmeter, it is a desirable requirement for flow measurement to have a uniform magnetic field distribution in the direction perpendicular to the fluid flow direction, and the magnetic field is uniformly distributed within the conduit including the electrodes by the action of the coil and the laminated iron core. I have to.

即ち不均一磁界分布の場合偏流による誤差が生じ電磁流
量計の測定機能を損うためである。That is, in the case of non-uniform magnetic field distribution, errors occur due to drift, impairing the measurement function of the electromagnetic flowmeter.

ところで最近導管、コイル、成層鉄心を外筐内部に備え
る代りに成層鉄心と外筐とを兼用する成層鉄心（コア）
なしの電磁流量計が作られている。By the way, recently, instead of providing conduits, coils, and a stratified iron core inside the outer casing, a stratified iron core (core) that serves both the stratified iron core and the outer casing has been developed.
An electromagnetic flow meter is manufactured without.

この場合の外筐は磁気的に同一特性の強磁性体の部材例
えば鋼板を溶接して作られているのが一般的である。In this case, the outer casing is generally made by welding a ferromagnetic member, such as a steel plate, with magnetically identical characteristics.

しかしながらこの溶接部が磁路中に形成されることにな
るので、外筐における磁気対称性を乱す原因になり、当
然導管内の磁界分布に影響が表われることになるのでコ
アなし電磁流量計の外筐の溶接部が流量測定において諸
問題を起している。However, since this weld is formed in the magnetic path, it causes disturbance of the magnetic symmetry in the outer casing, which naturally affects the magnetic field distribution in the conduit. The welds on the outer casing cause problems in flow measurement.

本考案の目的は、コアなし電磁流量計の外筐の溶接部を
、磁束密度が略零の所の位置および磁束方向に一致する
位置に形成するようにし、溶接部により外筐における磁
気対称性の乱れをできる限り少なくして外筐の溶接部に
より生ずる諸現象をなくし得る電磁流量計を提供するこ
とにある。The purpose of the present invention is to form the welded part of the outer casing of a coreless electromagnetic flowmeter at a position where the magnetic flux density is approximately zero and at a position that coincides with the magnetic flux direction. An object of the present invention is to provide an electromagnetic flowmeter that can eliminate various phenomena caused by welded parts of an outer casing by minimizing disturbances in the flow rate.

以下本考案の一実施例を図面を参照しながら説明する。An embodiment of the present invention will be described below with reference to the drawings.

第１、第２図において、対向するそれぞれのイ装置の内
壁に電気的絶縁を保って電極１１を備え、流体１２を通
す導管１３はこの２つの電極１１を通る直線およびこの
導管１３を流れる方向に対し直角方向の面に均一分布の
磁界を生ずるコイル１４゜１４′を外周部に設けである
。In FIGS. 1 and 2, an electrode 11 is provided on the inner wall of each of the opposing A devices while maintaining electrical insulation, and a conduit 13 through which the fluid 12 passes is a straight line passing through these two electrodes 11 and a direction in which it flows through the conduit 13. A coil 14° 14' is provided on the outer periphery to generate a uniformly distributed magnetic field in a plane perpendicular to the magnetic field.

導管１３を囲む外筐１５は強磁性体の部材例えば鋼板を
折曲げ加工し、鋼板と鋼板とのつなぎ目を溶接して作る
もので、流体の流れ方向と同一方向に形成された前記溶
接部１６（第１図）は前記２つの電極を通る直線および
導管を流れる方向に対し直角方向に、また導管の管軸方
向に対し直角方向に形成された熔接部１９（第２図）は
、この管軸に対し直角方向にそれぞれ位置するようにし
７て導管の外周部に固定する。The outer casing 15 surrounding the conduit 13 is made by bending a ferromagnetic material, such as a steel plate, and welding the joint between the steel plates.The welded portion 16 is formed in the same direction as the fluid flow direction. (Fig. 1) shows a straight line passing through the two electrodes and a direction perpendicular to the direction of flow in the conduit, and a welded part 19 (Fig. 2) formed perpendicular to the axial direction of the conduit. They are each positioned perpendicularly to the axis 7 and fixed to the outer periphery of the conduit.

なお１７は外筐を固定台に取付けるための取付台で゛あ
る。Note that 17 is a mounting base for mounting the outer casing on a fixed base.

このような構成の電磁流量計においては、コイル１４．
１４’により導管→流体→導管→外筐を通る２つの磁束
の磁路１Ｂ、１Ｂ’が形成される。In the electromagnetic flowmeter having such a configuration, the coil 14.
Two magnetic flux paths 1B and 1B' passing through the conduit → fluid → conduit → outer casing are formed by 14'.

そのうちの磁路でもつとも磁束密度の高い所は電極近傍
の外筐で、低い所は磁極近傍の外筐であるがられずかな
磁気抵抗の変化でも磁気的に大きく変化するところは電
極近傍である。Among these, the part of the magnetic path where the magnetic flux density is highest is in the outer casing near the electrode, and the lower part is in the outer casing near the magnetic pole, but the part where even a small change in magnetic resistance causes a large magnetic change is near the electrode. .

前記２つの磁路１８，１Ｂ’のうち一方の磁路に磁気抵
抗を変える例えば溶接部が存在するとこれら２つの磁路
の磁気的対称性はなくなる。If one of the two magnetic paths 18, 1B' has, for example, a welded portion that changes the magnetic resistance, the magnetic symmetry between these two magnetic paths will be lost.

しかし溶接部を磁極近傍に設けるか、或は電極近傍に設
けるかにまり外筐内における磁束密度分布の変化の表わ
れ方をもなくし得る。However, by providing the welded portion near the magnetic pole or near the electrode, it is possible to eliminate the appearance of changes in the magnetic flux density distribution within the outer casing.

即ち一方の磁路中でかつ磁極近傍に溶接部を位置させた
場合には外筐内における一方の磁路の磁束密度分布をほ
ぼ他方の磁路の磁束密度分布とあまり違わないようにす
ることができる。In other words, when the welding part is located in one magnetic path and near the magnetic pole, the magnetic flux density distribution of one magnetic path in the outer casing must be made not to differ much from the magnetic flux density distribution of the other magnetic path. Can be done.

また鋼板のつなぎ目を磁路方向に一致して溶接（第２図
の１７）する場合には、一方の磁路と他方の磁路におい
てこれら磁路を横切るような溶接部がないため一方の磁
路と他方の磁路とにおける磁気的な非対称性を生じるこ
とがなくなる。In addition, when welding the joints of steel plates in alignment with the magnetic path direction (17 in Figure 2), there is no weld that crosses the magnetic paths in one magnetic path and the other magnetic path. No magnetic asymmetry occurs between the magnetic path and the other magnetic path.

したがって外筐における２つの磁路のうちいずれか一方
に溶接部があってもこれら磁路はほぼ磁気的対称性を維
持できておるので、溶接部により生ずる流量測定に悪影
響を及ぼす要因が除去できる。Therefore, even if there is a weld on one of the two magnetic paths in the outer casing, these magnetic paths can maintain almost magnetic symmetry, so it is possible to eliminate factors that adversely affect flow measurement caused by welds. .

以上詳述した本考案は、外筐の溶接部が導管の管軸方向
に一致している場合、磁束密度をほぼ零の磁極の位置に
、また外筐の溶接部が導管の管軸方向に対し直角方向の
場合、この管軸方向に対し直角方向の位置になるよう外
筐を導管に設ける構成にし、外筐の磁路中に溶接部があ
っても外筐の磁気対称性を維持できるもので、外筐がコ
アの機能を兼ねる電磁流量計においては顕著な作用効果
を奏し得る。The present invention described in detail above has the advantage that when the welded part of the outer casing is aligned with the axial direction of the conduit, the magnetic flux density is set to the magnetic pole position of almost zero, and the welded part of the outer casing is aligned with the axial direction of the conduit. On the other hand, in the case of a perpendicular direction, the outer casing is installed on the conduit so that it is perpendicular to the pipe axis direction, and even if there is a welded part in the magnetic path of the outer casing, the magnetic symmetry of the outer casing can be maintained. This can produce remarkable effects in an electromagnetic flowmeter in which the outer casing also functions as the core.

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

第１図は、本考案を用いた電磁流量計の横断面図、第２
図は第１図の電磁流量計の側面を示す図である。 １１・・・・・・電極、１３・・・・・・導管、１４．
１４’・・・・・・コイル、１５・・・・・・外筐、１
６．１９’・・・・・・溶接部、１８．１８’・・・・
・・磁路。Figure 1 is a cross-sectional view of an electromagnetic flowmeter using the present invention;
The figure is a side view of the electromagnetic flowmeter shown in FIG. 1. 11... Electrode, 13... Conduit, 14.
14'... Coil, 15... Outer casing, 1
6.19'...Welded part, 18.18'...
...magnetic path.

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] 対向する位置に一対の電極を有し、被測定流体を流通さ
せる導管と、前記導管の外周に配置され、前記一対の電
極に被測定流体の流速に比例した起電力を得るようにほ
ぼ均一分布の磁界を前記導管内に発生するコイルと、前
記導管内の磁路を形成するため前記一対の電極を含む前
記導管を外側から囲み、溶接部を有する外筐とからなり
、前記外筐は、軸方向に溶接部をもつ複数の筒体を溶接
により縦続して形成され、各溶接部が磁束密度を略零と
する位置または磁路の帰路方向に沿った位置に一致した
ことを特徴とする電磁流量計。A conduit having a pair of electrodes at opposing positions and through which a fluid to be measured flows; and a conduit arranged around the outer periphery of the conduit so as to generate an electromotive force proportional to the flow velocity of the fluid to be measured, which is distributed almost uniformly across the pair of electrodes. a coil that generates a magnetic field in the conduit, and an outer casing that surrounds the conduit including the pair of electrodes from the outside to form a magnetic path in the conduit, and has a welded part, the outer casing: It is characterized in that it is formed by welding a plurality of cylindrical bodies with welded parts in the axial direction, and each welded part coincides with a position where the magnetic flux density is approximately zero or a position along the return path direction of the magnetic path. Electromagnetic flowmeter.