JPH0432327B2 - - Google Patents
Info
- Publication number
- JPH0432327B2 JPH0432327B2 JP56164258A JP16425881A JPH0432327B2 JP H0432327 B2 JPH0432327 B2 JP H0432327B2 JP 56164258 A JP56164258 A JP 56164258A JP 16425881 A JP16425881 A JP 16425881A JP H0432327 B2 JPH0432327 B2 JP H0432327B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- measuring tube
- electromagnetic flowmeter
- pole plate
- magnetic field
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000005291 magnetic effect Effects 0.000 claims description 172
- 230000004907 flux Effects 0.000 claims description 65
- 230000005284 excitation Effects 0.000 claims description 45
- 238000009826 distribution Methods 0.000 claims description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 17
- 238000005259 measurement Methods 0.000 claims description 15
- 239000003302 ferromagnetic material Substances 0.000 claims description 11
- 239000012530 fluid Substances 0.000 claims description 10
- 230000013011 mating Effects 0.000 claims description 9
- 239000000696 magnetic material Substances 0.000 claims description 7
- 239000012212 insulator Substances 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims 1
- 230000002093 peripheral effect Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 230000002411 adverse Effects 0.000 description 3
- 230000005294 ferromagnetic effect Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 231100000989 no adverse effect Toxicity 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/588—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters combined constructions of electrodes, coils or magnetic circuits, accessories therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/586—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters constructions of coils, magnetic circuits, accessories therefor
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measuring Volume Flow (AREA)
Description
【発明の詳細な説明】
本発明は、電磁流量計に係り、特に口径が50mm
程度以上の短面間形の電磁流量計に関するもので
ある。[Detailed Description of the Invention] The present invention relates to an electromagnetic flowmeter, and particularly has a diameter of 50 mm.
The present invention relates to a short surface type electromagnetic flowmeter of approximately 100 to 100 mm.
従来形の電磁流量計は、被測定流体を通す測定
管の内面に一対の電極を設け、この電極と測定管
軸を含む面に垂直な磁束を発生するようにループ
状の励磁コイルが設けられており、この磁束の漏
洩を防止するため筒状のコアが励磁コイルの外側
に設置され、更にその外側にはこれら全体を収め
る外筐があり、外筐の両端に管路に取付けるため
のフランジを有する構造である。励磁コイルは測
定管の外側で充分広い空間を占めているため外筐
がフランジの取付ボルトサークルより太くなり、
また面間距離も大きいので取付ボルトとして通し
ボルトを用いることができない。重量も著しく重
く、取付工事が大変であるというのが常識になつ
ていた。 Conventional electromagnetic flowmeters are equipped with a pair of electrodes on the inner surface of a measurement tube through which the fluid to be measured passes, and a loop-shaped excitation coil that generates a magnetic flux perpendicular to the plane that includes the electrodes and the axis of the measurement tube. In order to prevent leakage of this magnetic flux, a cylindrical core is installed outside the excitation coil, and further outside is an outer casing that houses the whole of the core, and flanges at both ends of the outer casing for attaching to the conduit. It is a structure with The excitation coil occupies a sufficiently large space outside the measuring tube, so the outer casing is thicker than the flange's mounting bolt circle.
Furthermore, since the distance between the surfaces is large, through bolts cannot be used as mounting bolts. It had become common knowledge that they were extremely heavy and difficult to install.
この難点を解消する目的で、円筒形の強磁性体
のリング内に一対の励磁コイルがリングの長手軸
線に直角な軸線に沿つて対向して支持され、リン
グ内に同心的にプラスチツク製の円筒体を配設し
て測定管とし、この測定管の一端には小径のフラ
ンジ、他端には前記リングに嵌合する径のフラン
ジがそれぞれ設けられ、更に測定管のフランジ間
の中央に前記一対の励磁コイルの軸線およびリン
グの長手軸線にそれぞれ直交する方向をとつて一
対の電極が設けられ、リングと測定管との間の空
間にエポキシ樹脂のような充填材を充填して環状
圧力容器を形成してなる電磁流量計が提案されて
いる。この電磁流量計ではリングと測定管との間
の空間に取付ボルトを通す穴を有し、通しボルト
を用いて管路の相手フランジ間にはさみ込んで取
付けるようになつており、取付用のフランジを持
たないフランジレスの構造である。したがつて前
述した従来形にくらべると重量も大幅に減少し、
取付も容易になる。 In order to overcome this difficulty, a pair of excitation coils are supported within a cylindrical ferromagnetic ring, facing each other along an axis perpendicular to the longitudinal axis of the ring, and a plastic cylinder is mounted concentrically within the ring. One end of this measuring tube is provided with a small diameter flange, the other end is provided with a flange having a diameter that fits into the ring, and the measuring tube has a pair of flanges in the center between the flanges. A pair of electrodes are provided perpendicularly to the axis of the excitation coil and the longitudinal axis of the ring, and a filler such as epoxy resin is filled in the space between the ring and the measuring tube to form an annular pressure vessel. An electromagnetic flowmeter has been proposed. This electromagnetic flowmeter has a hole for passing a mounting bolt in the space between the ring and the measuring pipe, and is designed to be installed by inserting it between the mating flanges of the conduit using a through bolt. It has a flangeless structure. Therefore, compared to the conventional type mentioned above, the weight is significantly reduced,
Installation is also easier.
しかしながら、この電磁流量計は取付ボルト用
の穴と穴との間に励磁コイルを配置している関係
で、口径は100mm程度までしかできない。口径が
100mm程度以上になると、規格によりフランジの
ボルト穴の数が多くなり、取付ボルト用の穴と穴
との間隔がせまくなるため、このせまい空間に励
磁コイルを配置することが不可能になるため、口
径が100mm程度におさえられていた。また、この
電磁流量計の両端面はエポキシ樹脂からなる環状
圧力容器の端面およびプラスチツク製の測定管フ
ランジで形成されていて磁気的なシールドがなさ
れていないため励磁コイルの鉄心の外径にくらべ
て面間距離を充分大きくする必要があり、短面間
化の点では不充分な結果しか得られていなかつ
た。 However, because this electromagnetic flowmeter has an excitation coil placed between the mounting bolt holes, the diameter can only be up to about 100 mm. The caliber is
When it is about 100mm or more, the number of bolt holes in the flange increases according to the standard, and the distance between the mounting bolt holes becomes narrow, making it impossible to place the excitation coil in this narrow space. The diameter was kept to around 100mm. In addition, both end faces of this electromagnetic flowmeter are formed by the end faces of an annular pressure vessel made of epoxy resin and a plastic measuring tube flange, and because they are not magnetically shielded, the outer diameter of the excitation coil is smaller than the outer diameter of the excitation coil's iron core. It is necessary to make the distance between the surfaces sufficiently large, and insufficient results have been obtained in terms of shortening the distance between the surfaces.
本発明は、口径50mm程度以上の大口径に対して
も実現可能で、充分短面間化され、重量が軽減さ
れて管路に通しボルトを用いて容易に取付けるこ
とができ、更に測定管内の流体の偏流による誤差
を小さくできる磁束分布が得られる電磁流量計を
提供することを目的とする。 The present invention can be realized even for large diameters of about 50 mm or more, has a sufficiently short distance, is light in weight, can be easily installed using bolts through the pipe, and can be installed easily in the measurement pipe. It is an object of the present invention to provide an electromagnetic flowmeter that can obtain a magnetic flux distribution that can reduce errors caused by fluid drift.
この目的を達成するために本発明では、第１階
微分または第２階微分がゼロとなる磁束を発生す
る方形波励磁、三角波励磁または直流励磁を行な
う磁界発生装置を用いるようにし、磁束の第２階
微分がゼロである領域を測定に用いることにより
本体ケーシング（コア兼用）に磁束が流れ込んで
も性能上悪影響を及ぼす交流現象がほとんど発生
しないため、ノイズ軽減用の成層コアを本体ケー
シングの内側に設ける必要がなくなり本体ケーシ
ングを薄く且つ小形にすることができた。また、
方形波励磁にしたことにより、商用電源ノイズや
その他のノイズの除去が容易となつて、交流励磁
のときの磁束密度の1/5〜1/10程度にしても充分
Ｓ／Ｎの良い測定が可能になり、励磁コイルを小
さくし、磁極板を大きくしても測定に必要な磁束
を得ることができ、このことから励磁コイルの小
形化を可能にして取付ボルト用の穴と穴との間に
磁界発生装置を収めることを可能にした。更に本
体ケーシングへの磁束の流れ込みがあつても悪影
響がないことと磁極板を大きくできる点を利用し
て、磁極板の形状、寸法を変えて本体ケーシング
との位置関係を変えることや、磁極板の外側に複
数のコイルが配設された構造に磁界発生装置を形
成し、各コイルのターン数や励磁電流を異ならせ
る等の手段により偏流による誤差を軽減する磁束
分布を得るようにした。 In order to achieve this object, the present invention uses a magnetic field generator that performs square wave excitation, triangular wave excitation, or DC excitation that generates magnetic flux whose first or second differential is zero. By using the region where the second-order differential is zero for measurement, even if magnetic flux flows into the main body casing (also used as the core), AC phenomena that adversely affect performance will hardly occur, so a stratified core for noise reduction is placed inside the main body casing. This eliminates the need for the main body casing and allows the main body casing to be made thinner and smaller. Also,
By using square wave excitation, commercial power supply noise and other noises can be easily removed, and measurements with a sufficiently good S/N can be achieved even at a magnetic flux density of about 1/5 to 1/10 of AC excitation. This makes it possible to obtain the magnetic flux necessary for measurement even if the excitation coil is made smaller and the magnetic pole plate is made larger.This makes it possible to make the excitation coil smaller and to make the space between the holes for the mounting bolts smaller. This made it possible to fit a magnetic field generator into the Furthermore, taking advantage of the fact that even if magnetic flux flows into the main body casing, there is no negative effect and the magnetic pole plate can be made larger, it is possible to change the shape and dimensions of the magnetic pole plate to change its positional relationship with the main body casing. A magnetic field generating device is formed with a structure in which a plurality of coils are disposed outside the coil, and a magnetic flux distribution that reduces errors due to drifting is obtained by means such as varying the number of turns and excitation current of each coil.
以下、本発明の実施例を図面を参照して説明す
る。第１図ａ，ｂに本発明一実施例の電磁流量計
を示す。同図において、１は本体ケーシングで、
短いドラム状をなし強磁性体で作られ、取り付け
られる相手フランジの取付ボルト１０１のサーク
ル内に収まる寸法に形成されている。本体ケーシ
ングの頂部および底部にはそれぞれ磁界発生装置
２を装着するための突出部１ａが形成されてい
る。また、１対の突出部１ａの軸線と直角な直径
軸線上に位置して本体ケーシング１の両側面には
電極取付作業用開口部１ｂがそれぞれ突設され、
蓋体６で閉塞されている。３は測定管で、非磁性
体で作られ、本体ケーシング１内に同心的に配置
され、本体ケーシング１の両端の鏡板部１ｄで保
持固定されている。測定管３の内面にはライニン
グ７が施されている。測定管３には、磁界発生装
置２の軸線方向および測定管３の管軸方向にそれ
ぞれ直交する直径軸線上に位置して一対の電極５
が測定管と絶縁されて装着されている。磁界発生
装置２は励磁コイル４が巻かれた鉄心２ｃと測定
管３の外側に沿う磁極板２ａと突出部１ａの開口
端を閉塞し鉄心２ｃを保持している継磁極２ｂと
で構成され、本体ケーシング１の突出部１ａの穴
に励磁コイル４を内嵌して装着されている。そし
て、励磁コイル４は方形波または三角波、あるい
は直流で励磁され第１階微分または第２階微分が
ゼロである磁束を発生し、この磁束の中心線は一
対の電極５を結ぶ線および測定管３の管軸にそれ
ぞれ直交する方向をとつて測定管３内を流れる流
体に印加される。また、磁界発生装置２の励磁コ
イル４を収納する本体ケーシング１の突出部１ａ
の穴の測定管３の管軸に直角な方向に穴寸法lH
と、磁極板２ａの測定管３の管軸に直角な方向の
寸法lPとの関係が、lP＞lHであるようにそれぞれ
の寸法を定めて製作する。 Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1a and 1b show an electromagnetic flowmeter according to an embodiment of the present invention. In the same figure, 1 is the main casing,
It has a short drum shape, is made of ferromagnetic material, and is sized to fit within the circle of the mounting bolt 101 of the mating flange to be attached. Projections 1a for mounting the magnetic field generator 2 are formed at the top and bottom of the main casing, respectively. Furthermore, openings 1b for electrode attachment work are protrudingly provided on both sides of the main casing 1, located on the diameter axis perpendicular to the axis of the pair of protrusions 1a,
It is closed with a lid body 6. A measuring tube 3 is made of a non-magnetic material, is arranged concentrically within the main casing 1, and is held and fixed by end plates 1d at both ends of the main casing 1. The inner surface of the measuring tube 3 is provided with a lining 7. The measuring tube 3 has a pair of electrodes 5 located on the diameter axis perpendicular to the axial direction of the magnetic field generator 2 and the tube axial direction of the measuring tube 3.
is installed insulated from the measuring tube. The magnetic field generator 2 is composed of an iron core 2c around which an excitation coil 4 is wound, a magnetic pole plate 2a along the outside of the measuring tube 3, and a relay pole 2b that closes the open end of the protrusion 1a and holds the iron core 2c. The excitation coil 4 is fitted into a hole in the protruding portion 1a of the main body casing 1. The excitation coil 4 is excited by a square wave, a triangular wave, or a direct current to generate a magnetic flux whose first or second differential is zero, and the center line of this magnetic flux is the line connecting the pair of electrodes 5 and the measuring tube. The voltage is applied to the fluid flowing inside the measurement tube 3 in directions perpendicular to the tube axes of the measurement tubes 3 and 3, respectively. Further, a protrusion 1a of the main body casing 1 that houses the excitation coil 4 of the magnetic field generator 2
Measuring the hole in the hole in the direction perpendicular to the tube axis of tube 3 .
and the dimension l P of the magnetic pole plate 2a in the direction perpendicular to the tube axis of the measuring tube 3. Each dimension is determined and manufactured so that l P >l H.
次に、上記のように構成された本発明一実施例
の電磁流量計の作用および効果につき説明する。 Next, the operation and effects of the electromagnetic flowmeter according to one embodiment of the present invention configured as described above will be explained.
〔１〕 第１階微分または第２階微分がゼロとな
る磁束を発生する磁界発生装置を用いて磁束の
第２階微分がゼロである領域を測定に用いるよ
うにしたことにより、磁束が本体ケーシング１
に流れ込んでも性能上悪影響を及ぼす交流現象
がほとんど発生しないので、ノイズを軽減する
ために本体ケーシングに内接する成層コアは不
要となり、本体ケーシング１を薄く且つ小形に
作ることができ、更に測定管端以外は強磁性体
製の本体ケーシングで囲まれているため面間距
離も短くすることができて電磁流量計が軽量化
される。[1] By using a magnetic field generator that generates magnetic flux where the first or second derivative is zero, the region where the second derivative of the magnetic flux is zero is used for measurement, so that the magnetic flux is Casing 1
Since almost no alternating current phenomenon that adversely affects performance occurs even if the flow flows into the main body casing, there is no need for a stratified core inscribed in the main body casing to reduce noise, and the main body casing 1 can be made thin and compact. Since the rest is surrounded by a main body casing made of ferromagnetic material, the distance between surfaces can be shortened, making the electromagnetic flowmeter lighter.
〔２〕 上記第１項のような磁束を発生するため
に方形波励磁を行なうことにより、商用電源ノ
イズやその他のノイズの除去が容易となるので
交流励磁のときの磁束密度の1/5〜1/10程度に
しても充分Ｓ／Ｎの良い測定が可能になり、こ
のため励磁コイルの小形化が可能になり、口径
が大きい場合に相手フランジの取付ボルトの数
が多くなつて取付ボルト用の穴と穴の間隔がせ
まくなつても、その穴と穴との間に磁界発生装
置を収めることができ、口径が100mm程度以上
の場合にも相手フランジの間にはさみ込んで通
しボルトを用いて管路に取付けることができる
フランジレス形の電磁流量計を実現することが
できる。[2] By performing square wave excitation to generate the magnetic flux as described in item 1 above, commercial power supply noise and other noises can be easily removed. Measurements with a sufficiently good S/N are possible even when the diameter is about 1/10, which makes it possible to downsize the excitation coil, and when the diameter is large, the number of mounting bolts on the mating flange increases. Even if the distance between the holes becomes narrow, the magnetic field generator can be placed between the holes, and even if the diameter is about 100 mm or more, it can be inserted between the mating flanges and used with a through bolt. A flangeless electromagnetic flowmeter that can be installed in pipelines can be realized.
〔３〕 上記第２項で述べた磁束密度を小さくし
てもＳ／Ｎの良い測定が可能であることから磁
極板を大きくしても測定に必要な磁束を得るこ
とができる点と、第１項で述べた本体ケーシン
グへの磁束の流れ込みがあつても悪影響のない
点とを利用して、磁極板２ａの測定管の管軸に
直角な方向の寸法lpを大きくし、磁極板２ａの
本体ケーシング１に対向した面と本体ケーシン
グ１との間の磁束の漏洩を活用することによつ
て、測定管３内の磁束分布を偏流による誤差の
発生を小さくするように調整することを可能に
した。[3] Since it is possible to measure with a good S/N even if the magnetic flux density is reduced as described in Section 2 above, the magnetic flux necessary for measurement can be obtained even if the magnetic pole plate is made large. Taking advantage of the fact that there is no adverse effect even if magnetic flux flows into the main body casing as described in Section 1, the dimension l p of the magnetic pole plate 2a in the direction perpendicular to the tube axis of the measuring tube is increased, and the magnetic pole plate 2a By utilizing the magnetic flux leakage between the surface facing the main body casing 1 and the main body casing 1, it is possible to adjust the magnetic flux distribution inside the measuring tube 3 so as to reduce errors caused by drifting. I made it.
この点につき下記により詳説する。周知のよう
に、均一磁界が印加された場合の電磁流量計の
「重み関数」は第２図に示すようになつており、
測定管内部の流体に誘起された起電力は電極５に
対して第２図に示されている数値のような寄与を
する。電磁流量計の測定管内の一対の電極を含む
断面における各点での発生起電力EXは、
EX＝Ｋ・Ｗ・Ｂ・Ｖ ここに、
Ｋ：比例定数
Ｗ：重み関数
Ｂ：磁束密度
Ｖ：流体の流速
で決まる。したがつて、均一磁界形の電磁流量計
は、被測定流体に偏流があれば、第２図の「重み
関数」に従つて誤差が発生する。即ち、図中0.65
の部分あるいは2.0の部分に偏流があつたとすれ
ば、電極への影響は0.65：2.0＝１：３となり、
３倍異つてくる。この差異をなくすには、Ｗ・Ｂ
＝一定にすればよい。即ち、第２図の「重み関
数」の逆数の磁束密度Ｂを分布させればよいこと
になる。 This point will be explained in detail below. As is well known, the "weighting function" of an electromagnetic flowmeter when a uniform magnetic field is applied is as shown in Figure 2.
The electromotive force induced in the fluid inside the measuring tube contributes to the electrode 5 as shown in FIG. The electromotive force EX generated at each point in the cross section including the pair of electrodes in the measurement tube of the electromagnetic flowmeter is EX = K・W・B・V where,
K: proportionality constant W: weighting function B: magnetic flux density V: determined by fluid flow velocity. Therefore, in a uniform magnetic field type electromagnetic flowmeter, if there is a drift in the fluid to be measured, an error occurs according to the "weighting function" shown in FIG. 2. That is, 0.65 in the figure
If there is a drift in the part or the part 2.0, the influence on the electrode will be 0.65:2.0=1:3,
It will be 3 times different. To eliminate this difference, W.B.
= Just keep it constant. That is, it is sufficient to distribute the magnetic flux density B which is the reciprocal of the "weighting function" shown in FIG.
Ｗ・Ｂ＝Ｗ・１／Ｗ＝１（一定）
いま、第３図に示すように、測定管の一対の電
極５を結ぶ直線（軸線Ｘ）上の電極近傍の位置を
Ｈ、前記軸線Ｘに直交する直径（軸線Ｚ）上の測
定管内壁近傍の位置をＶとすれば、Ｖの部分の磁
束密度BVとＨの部分の磁束密度BHとの比が３：
１になれば上述した理想状態に近くなる。そし
て、BV：BH＝３：１は理想的であるが、均一磁
界でのBV：BH＝１：１にくらべれば、BV：BH＝
ｎ：１におけるｎは理想値３でなくても効果があ
り、ｎの値が１より大であれば効果が出始め、ｎ
が３で理想的になり、ｎが３×３＝９になつたと
きに「重み関数」を乗算した誤差で比較してＶ位
置がＨ位置の３倍になつて、均一磁界における誤
差と同等になることになる。 W・B=W・1/W=1 (constant) Now, as shown in Fig. 3, the position near the electrode on the straight line (axis X) connecting the pair of electrodes 5 of the measuring tube is H, If the position near the inner wall of the measurement tube on the diameter (axis Z) orthogonal to is V, the ratio of the magnetic flux density B V at the V section and the magnetic flux density B H at the H section is 3:
If it becomes 1, it will be close to the above-mentioned ideal state. And, B V :B H = 3:1 is ideal, but compared to B V :B H = 1:1 in a uniform magnetic field, B V :B H =
It is effective even if n in n:1 is not the ideal value 3, and if the value of n is greater than 1, the effect starts to appear, and n
becomes ideal at 3, and when n becomes 3 x 3 = 9, comparing the error multiplied by the "weighting function", the V position becomes 3 times the H position, which is equivalent to the error in a uniform magnetic field. It will become.
ここで、第１図ａ，ｂの実施例における一対の
電極５を含む断面においての磁束の状態をみると
第４図のようになる。即ち、磁極板２ａの先端寄
りの磁束は、図示の如く本体ケーシング１の電極
近傍位置へ流れ込むものM1と、本体ケーシング
１の電極近傍位置から磁極板２a′へ流れ込むもの
M2とになる。その結果電極近傍位置Ｈにおける
軸線Ｘ方向の磁束は互に逆方向の成分が打消され
て弱くなる。そして磁極板２ａ，２a′の中心を結
ぶ軸線近傍の磁束はM0の如くなり、この部分の
磁束は位置Ｈにおける磁束にくらべて強く、一対
の電極５を含む断面における磁束分布を前述した
理想的分布に近づけることができる。 Here, when looking at the state of magnetic flux in the cross section including the pair of electrodes 5 in the embodiment shown in FIGS. 1a and 1b, it becomes as shown in FIG. 4. That is, the magnetic flux near the tip of the magnetic pole plate 2a flows into the magnetic pole plate 2a ' from the position near the electrode in the main casing 1, as shown in the figure.
It becomes M 2 . As a result, the magnetic flux in the direction of the axis X at the position H near the electrode becomes weaker because the components in opposite directions are canceled. The magnetic flux near the axis connecting the centers of the magnetic pole plates 2a and 2a' becomes M 0 , and the magnetic flux in this part is stronger than the magnetic flux at position H, and the magnetic flux distribution in the cross section including the pair of electrodes 5 is the ideal distribution.
さらに、第５図に示すように磁極板２ａの寸法
lpを大きくして、測定管３の軸心と磁極板２ａの
先端とを結ぶ線と一対の電極５を結ぶ線とのなす
角θを小さく（最小10°程度）してやつた場合に
は、磁極板２ａ，２a′の先端部における磁束の状
態は、磁極板と本体ケーシング１との間の漏洩が
増し、図示のM3、M4のようになる。このため電
極近傍位置Ｈにおける軸線Ｘ方向の磁束は一層弱
くなり、磁極板の中心部からの磁束M0が主体と
なる。 Furthermore, as shown in FIG. 5, the dimensions of the magnetic pole plate 2a are
When l p is increased and the angle θ between the line connecting the axis of the measuring tube 3 and the tip of the magnetic pole plate 2a and the line connecting the pair of electrodes 5 is made small (minimum about 10 degrees), The state of the magnetic flux at the tips of the magnetic pole plates 2a and 2a' becomes as shown in M 3 and M 4 as shown in the figure, as leakage between the magnetic pole plates and the main body casing 1 increases. Therefore, the magnetic flux in the axis X direction at the position H near the electrode becomes even weaker, and the magnetic flux M 0 from the center of the magnetic pole plate becomes the main component.
次に本発明による電磁流量計の種々の実施態様
につき説明する。 Next, various embodiments of the electromagnetic flowmeter according to the present invention will be described.
〔Ａ〕 第１図ａ，ｂで示した実施例において
は、磁界発生装置２を構成する継磁極２ｂ、鉄
心２ｃ、磁極板２ａの三者が互に締結されて一
体化されている例を示したが、これに限らず、
第６図ａ，ｂ，ｃ，ｄに示すように、継磁極２
ｂ、鉄心２ｃ、磁極板２ａのいずれか二者の間
に磁気的ギヤツプＳを設けた構造でもよい。第
６図ｃに示すものは、磁極板２ａを測定管３お
よび鉄心２ｃから離してその間に磁気的ギヤツ
プをもたせた構造で、磁極板２ａを非磁性ステ
ンレス材のカラー２１をスペーサとして本体ケ
ーシング１に固定したものである。このように
磁極板２ａを予め固定した本体ケーシング１に
測定管３を挿入し、さらに励磁コイルを巻いた
鉄心２ｃに継磁極２ｂを取着したものを本体ケ
ーシング１の突出部１ａの穴に挿入して電磁流
量計を組み立てることができ、製作を容易化す
る構造である。[A] In the embodiment shown in FIGS. 1a and 1b, an example is shown in which the relay pole 2b, the iron core 2c, and the magnetic pole plate 2a, which constitute the magnetic field generator 2, are connected to each other and integrated. Although not limited to this,
As shown in Figure 6 a, b, c, d, the relay pole 2
A structure may be adopted in which a magnetic gap S is provided between any two of the iron core 2c and the magnetic pole plate 2a. The structure shown in FIG. 6c has a structure in which the magnetic pole plate 2a is separated from the measuring tube 3 and the iron core 2c with a magnetic gap therebetween. It is fixed at . Insert the measuring tube 3 into the main body casing 1 with the magnetic pole plate 2a fixed in advance in this way, and then insert the relay magnetic pole 2b attached to the iron core 2c wrapped with the excitation coil into the hole in the protrusion 1a of the main body casing 1. The electromagnetic flowmeter can be assembled by using the same structure, making it easy to manufacture.
〔Ｂ〕 第７図に示すように、鉄心２ｃおよび磁
極板２ａを一体にして継磁極２ｂに対して調整
ねじ２２により移動可能に取着して磁極板２ａ
と本体ケーシング１との間隔を可変にし、更に
磁極板２ａの中心に突部２３を形成する。一
方、一対の電極５を結ぶ直線上に位置させて本
体ケーシング１に強磁性体製の磁束調整棒２４
を軸方向に移動可能に設ける。また、磁極板２
ａの先端と測定管３の軸心とを結ぶ直線と一対
の電極５を結ぶ直線とのなす角がほぼ45°をな
すように磁極板２ａの寸法を定める。この実施
例の電磁流量計では、突部２２によりＶ位置の
磁束が多少強まり、また、磁束調整棒２４によ
りＨ位置の磁束が弱まり、一対の電極を含む断
面における磁束密度分布を「重み関数」の逆数
の分布に近い理想的状態にすることができた。
なお、磁極板２ａの形状は第１図、第７図に示
したものに限らず第８図ａ，ｂに示すように
種々な形状にすることができる。また、磁極板
２ａと本体ケーシング１との間隔調整は第７図
に示した調整ねじ２２によるほか、継磁極２ｂ
と鉄心２ｃとの間にスペーサを介在させ、スペ
ーサの厚さ、枚数などにより調節するようにし
てもよい。また、磁束調整棒２４はそれぞれの
電極の近傍に複数本設けるようにしてもよい。[B] As shown in FIG. 7, the iron core 2c and the magnetic pole plate 2a are integrated and movably attached to the relay magnetic pole 2b with an adjustment screw 22, and the magnetic pole plate 2a is assembled.
The distance between the magnetic pole plate 2a and the main body casing 1 is made variable, and a protrusion 23 is formed at the center of the magnetic pole plate 2a. On the other hand, a magnetic flux adjusting rod 24 made of a ferromagnetic material is placed on the main casing 1 on a straight line connecting the pair of electrodes 5.
is provided so as to be movable in the axial direction. In addition, magnetic pole plate 2
The dimensions of the magnetic pole plate 2a are determined so that the angle formed by the straight line connecting the tip of a and the axis of the measuring tube 3 and the straight line connecting the pair of electrodes 5 is approximately 45°. In the electromagnetic flowmeter of this embodiment, the magnetic flux at the V position is somewhat strengthened by the protrusion 22, and the magnetic flux at the H position is weakened by the magnetic flux adjustment rod 24, and the magnetic flux density distribution in the cross section including the pair of electrodes is controlled by a "weighting function". We were able to create an ideal state close to the distribution of the reciprocal of .
The shape of the magnetic pole plate 2a is not limited to that shown in FIGS. 1 and 7, but can be made into various shapes as shown in FIGS. 8a and 8b. In addition, the distance between the magnetic pole plate 2a and the main body casing 1 can be adjusted by using the adjusting screw 22 shown in FIG.
A spacer may be interposed between the iron core 2c and the iron core 2c, and the thickness and number of the spacers may be adjusted. Further, a plurality of magnetic flux adjustment rods 24 may be provided near each electrode.
〔Ｃ〕 第９図に示すように、電極５近傍以外の
部分の磁束分布のばらつきを調整するために、
強磁性体製の磁束調整棒２５を一対の電極を含
み測定管軸に直角な平面と本体ケーシング１と
の交線の近傍位置に測定管３との距離を可変で
きるように適宜の数だけ本体ケーシングに設け
ることもできる。[C] As shown in FIG. 9, in order to adjust the variation in magnetic flux distribution in areas other than the vicinity of the electrode 5,
A suitable number of magnetic flux adjustment rods 25 made of ferromagnetic material are placed in the vicinity of the intersection line between the main body casing 1 and a plane perpendicular to the measuring tube axis, so that the distance from the measuring tube 3 can be varied. It can also be provided in the casing.
〔Ｄ〕 第１０図ａ，ｂ，ｃに示す実施例は、非
磁性体からなる測定管３の励磁コイル４に対向
した部分を強磁性体におきかえて作り、この部
分をして磁界発生装置２の磁極板２ａの機能を
兼ねさせたものである。このような測定管３
は、例えば第１０図ｃに示すように、測定管を
展開した形状寸法をもつ非磁性体の板３の磁極
板に相当する位置を切り抜き、そこに強磁性体
の板２ａを溶接した後、所定の径の円筒状に成
形することにより製作することができる。第１
１図ａ，ｂおよび第１２図ａ，ｂは測定管の一
部が磁極板の機能を兼ねた電磁流量計の他の実
施例を示すもので、第１１図ａ，ｂのものは、
本体ケーシング１がフランジ取付ボルトを貫通
させるような外径をもつ寸法に形成された例で
ある。また第１２図ａ，ｂのものは、本体ケー
シング１がフランジ取付ボルトを貫通させる外
径をもつ寸法に形成されるとともに、磁界発生
装置２が測定管３の軸線方向に配列された２個
の励磁コイル４，４′を具えた構造に形成され
た例である。[D] The embodiment shown in FIGS. 10a, b, and c is made by replacing the part of the measuring tube 3 made of a non-magnetic material facing the excitation coil 4 with a ferromagnetic material, and using this part as a magnetic field generating device. This serves also as the function of the second magnetic pole plate 2a. Such a measuring tube 3
For example, as shown in FIG. 10c, after cutting out a position corresponding to the magnetic pole plate of a non-magnetic plate 3 having the shape and dimensions of the expanded measuring tube, and welding a ferromagnetic plate 2a there, It can be manufactured by molding it into a cylindrical shape with a predetermined diameter. 1st
Figures 1a and b and Figures 12a and b show other embodiments of an electromagnetic flowmeter in which a part of the measuring tube also functions as a magnetic pole plate.
This is an example in which the main body casing 1 is formed to have an outer diameter that allows the flange mounting bolt to pass through. In addition, in the case of FIGS. 12a and 12b, the main body casing 1 is formed to have an outer diameter that allows the flange mounting bolt to pass through, and the magnetic field generating device 2 has two pieces arranged in the axial direction of the measuring tube 3. This is an example formed in a structure including excitation coils 4 and 4'.
〔Ｅ〕 第１３図ａ，ｂに示す実施例は、強磁性
体製の本体ケーシング１の内径をその電磁流量
計の口径に等しい寸法に形成し、磁極板２ａに
相当する断面形状をもつた非磁性体製の筒状の
磁気絶縁体２６を本体ケーシング１の内壁には
め込んで磁極板２ａを本体ケーシング１の内壁
から磁気的に絶縁した構造をなしており、本体
ケーシング１の内壁と磁気絶縁体２６と磁極板
２ａとで測定管を構成し、内面にはライニング
７が施されている。なお図中２７はリード線を
通す穴である。[E] In the embodiment shown in FIGS. 13a and 13b, the inner diameter of the ferromagnetic body casing 1 is equal to the diameter of the electromagnetic flowmeter, and the cross-sectional shape corresponds to the magnetic pole plate 2a. A cylindrical magnetic insulator 26 made of a non-magnetic material is fitted into the inner wall of the main body casing 1 to magnetically insulate the magnetic pole plate 2a from the inner wall of the main body casing 1. The body 26 and the magnetic pole plate 2a constitute a measuring tube, and the inner surface is lined with a lining 7. Note that 27 in the figure is a hole through which a lead wire is passed.
〔Ｆ〕 第１４図ａ，ｂに示す実施例は、取付ボ
ルト用の穴と穴の間隔が小さくて、穴と穴の間
に磁界発生装置を装着する突出部を入れるスペ
ースが得られない場合に対処した構造を示して
いる。２個の取付ボルト用穴を本体ケーシング
１の突出部１ａの中へとり込み、取付ボルトを
磁気的に絶縁するために非磁性体製の取付ボル
ト貫通用保護管２８を本体ケーシング１の突出
部１ａ内に配置したものである。[F] The embodiments shown in Figures 14a and 14b are used when the distance between the mounting bolt holes is small and there is no space between the holes to insert the protrusion for mounting the magnetic field generator. This shows a structure that addresses this issue. The two mounting bolt holes are taken into the protruding part 1a of the main body casing 1, and in order to magnetically insulate the mounting bolts, a protective tube 28 for penetrating the mounting bolts made of a non-magnetic material is inserted into the protruding part of the main body casing 1. It is placed inside 1a.
〔Ｇ〕 第１５図ａ，ｂに示す実施例は、本体ケ
ーシング１の接続端に相手フランジの取付ボル
トのうちの２本づつを通す穴を有する耳状のフ
ランジ２９，３０，３１，３２を設けたもので
ある。管路へ接続するときに、例えば耳状のフ
ランジ２９，３０により短い取付ボルト１０２
を使つて相手フランジ１０４に電磁流量計を片
持取付してその重量を配管１０３で支えてお
き、それから完全な取付作業を行なえるように
したもので、取付作業を容易且つ安全にする効
果がある。したがつて、耳状のフランジは本体
ケーシング１の接続端のいずれか一方に設けて
おいてもよい。[G] The embodiment shown in FIGS. 15a and 15b has ear-shaped flanges 29, 30, 31, and 32 each having holes for passing two of the mounting bolts of the mating flange at the connecting end of the main casing 1. It was established. When connecting to a pipeline, e.g. ear-shaped flanges 29, 30 allow short mounting bolts 102.
The electromagnetic flowmeter is cantilever-mounted on the mating flange 104 using the flange 104, its weight is supported by the piping 103, and then the complete installation work can be carried out, which has the effect of making the installation work easy and safe. be. Therefore, the ear-shaped flange may be provided on either one of the connection ends of the main casing 1.
〔Ｈ〕 第１６図ａ，ｂは、電極５の接液部の形
状の変形例を示すものである。第２図に示した
ように「重み関数」は電極の表面では著しく大
きくなるので、この影響を緩和するために電極
５の接液部を測定管の内壁から管の中心の方向
に突出させ、第１６図ａの如く円柱状や、第１
６図ｂの如く円錐状に形成したものである。[H] FIGS. 16a and 16b show modified examples of the shape of the liquid-contacting part of the electrode 5. As shown in FIG. 2, the "weighting function" becomes significantly larger on the surface of the electrode, so in order to alleviate this effect, the wetted part of the electrode 5 is made to protrude from the inner wall of the measuring tube toward the center of the tube. A cylindrical shape as shown in Figure 16a, or a first
It is formed into a conical shape as shown in Figure 6b.
〔Ｊ〕 第１７図ａ，ｂに示す実施例は、本体ケ
ーシング１の電極近傍位置に互に極性の異なる
１対の補助コイル４０ａ，４０ｂを配置したも
のである。補助コイル４０ａにより図示の磁束
Maを打消し、補助コイル４０ｂにより図示の
磁束Mbを打消すことによつて、電極近傍にお
ける一対の電極を結ぶ直線方向の磁束を弱め、
磁束分布を「重み関数」の逆数の分布に近づけ
るように調整することができる。[J] In the embodiment shown in FIGS. 17a and 17b, a pair of auxiliary coils 40a and 40b having mutually different polarities are arranged near the electrodes of the main casing 1. The magnetic flux shown by the auxiliary coil 40a
By canceling Ma and canceling the illustrated magnetic flux Mb by the auxiliary coil 40b, the magnetic flux in the linear direction connecting the pair of electrodes in the vicinity of the electrodes is weakened,
The magnetic flux distribution can be adjusted to approximate the distribution of the reciprocal of the "weighting function".
〔Ｋ〕 第１８図ａ，ｂに示す実施例は、磁界発
生装置２の磁極板２ａが測定管３の外周に沿つ
て一対の電極５の近傍まで延在した形状に形成
されており、且つ磁極板２ａの先端部の平面形
状が三角形状に形成されている例である。第５
図の場合と同様に電極近傍の磁束を弱めて磁束
分布を「重み関数」の逆数の分布に近づける作
用がある。さらに、磁極板２ａの先端部の平面
形状は、第１９図ａ，ｂ，ｃ，ｄに示すように
種々な形状にすることができ、それぞれの場合
で磁極板先端部と本体ケーシング１との間の磁
束の流れ方が微妙に変り、電極近傍の磁束の強
さを微妙に調製することができる。[K] In the embodiment shown in FIGS. 18a and 18b, the magnetic pole plate 2a of the magnetic field generating device 2 is formed in a shape extending along the outer periphery of the measuring tube 3 to the vicinity of the pair of electrodes 5, and This is an example in which the top end of the magnetic pole plate 2a has a triangular planar shape. Fifth
As in the case shown in the figure, it has the effect of weakening the magnetic flux near the electrodes and bringing the magnetic flux distribution closer to the distribution of the reciprocal of the "weighting function." Furthermore, the planar shape of the tip of the magnetic pole plate 2a can be made into various shapes as shown in FIGS. The way the magnetic flux flows between the electrodes changes slightly, making it possible to finely adjust the strength of the magnetic flux near the electrodes.
〔Ｌ〕 第２０図ａ，ｂ乃至第２５図は本発明に
よる電磁流量計における相手フランジの取付ボ
ルトに対する対応手段の種々な態様を示すもの
である。第２０図ａ，ｂは本体ケーシング１が
取付ボルトのサークルの内側に収まる寸法に形
成された場合である。第２１図ａ，ｂは取付ボ
ルトのうち対称位置にある２本の取付ボルトを
挿通させる金具５１を本体ケーシング１の長手
方向中心に設けた場合である。第２２図は前記
金具５１を本体ケーシング１の両接続端近傍に
それぞれ設けた場合である。第２３図ａ，ｂは
取付ボルトのサークルより本体ケーシング１の
外径を大きくして取付ボルトが本体ケーシング
１を貫通するようにした例である。第２４図
ａ，ｂは取付ボルトのうち磁界発生装置２の近
傍の２本を本体ケーシング１を貫通するように
した場合である。第２５図は本体ケーシング１
の両端部にそれぞれ取付ボルトを挿通させる穴
を有するフランジ５２を設けた場合である。[L] Figures 20a and 20b to 25 show various aspects of the means for accommodating the mounting bolts of the mating flange in the electromagnetic flowmeter according to the present invention. 20a and 20b show the case where the main body casing 1 is formed to a size that fits inside the circle of the mounting bolt. FIGS. 21a and 21b show a case where a metal fitting 51 through which two symmetrically located mounting bolts are inserted is provided at the center in the longitudinal direction of the main body casing 1. FIGS. FIG. 22 shows a case where the metal fittings 51 are provided near both connecting ends of the main casing 1. FIGS. 23a and 23b show an example in which the outer diameter of the main casing 1 is made larger than the circle of the mounting bolt so that the mounting bolt passes through the main casing 1. 24a and 24b show a case where two of the mounting bolts near the magnetic field generating device 2 are made to pass through the main body casing 1. Figure 25 shows main casing 1
This is a case in which flanges 52 having holes through which mounting bolts are inserted are provided at both ends of the flange 52, respectively.
〔Ｍ〕 第２６図に示す実施例は、磁極板２ａの
測定管の管軸に直角な方向の寸法を、励磁コイ
ルを収納する本体ケーシングの穴の測定管の管
軸に直角な方向の穴寸法より大きく形成した本
発明による電磁流量計を３連にして本体ケーシ
ング１におさめた例である。２連でもよいし、
更に多連にすることも可能である。また、各励
磁コイルは直列接続でもよいし、並列接続でも
よい。[M] In the embodiment shown in FIG. 26, the dimension of the magnetic pole plate 2a in the direction perpendicular to the tube axis of the measuring tube is the same as that of the hole in the main body casing housing the excitation coil in the direction perpendicular to the tube axis of the measuring tube. This is an example in which three electromagnetic flowmeters according to the present invention, which are formed larger than the dimensions, are housed in a main body casing 1. It may be 2 consecutive,
Furthermore, it is also possible to make it multiple. Further, each exciting coil may be connected in series or in parallel.
〔Ｎ〕 第２７図ａ，ｂに示す実施例は、磁界発
生装置２が複数の励磁コイルから構成され、そ
れぞれの磁極板２ａを測定管３に対向させて本
体ケーシング１に装着された構造に作られた例
である。第２７図ａ，ｂの実施例では、励磁コ
イルが一対の電極を含み測定管の管軸に直角な
面に、４１ａと４１ｂ，４２ａと４２ｂ，４３
ａと４３ｂの３対が配置され、更に一対の電極
を含む面から測定管の管軸方向に離れて４１ａ
と４１ｂの対の両隣にそれぞれ４４ａと４４
ｂ，４５ａと４５ｂの各対が配置されている。
そして、各励磁コイルのターン数をそれぞれ異
ならせて作ることにより、磁束分布が「重み関
数」の影響を軽減する如き磁束分布になるよう
にしている。また、ターン数を変えて作るかわ
りに、各励磁コイルに印加する励磁電流をそれ
ぞれ異ならせて同じような効果を得るようにす
ることもできる。更に、ターン数と励磁電流の
両者を変えて同様な調整を行なうこともでき
る。また更に、第２７図ａのＺ矢符方向より見
た平面図である第２８図ａに示すように、中央
部に長形の励磁コイル４６を配置し、それに隣
接させて丸形の励磁コイル４７を２個配置した
り、同様に第２８図ｂに示すように、中央部の
長形の励磁コイル４６の周囲に複数の丸形の励
磁コイル４７を配置したり、第２８図ｃに示す
ように多数の丸形の励磁コイル４７を分布配置
したりした構成に磁界発生装置を構成すること
もできる。[N] The embodiment shown in FIGS. 27a and 27b has a structure in which the magnetic field generator 2 is composed of a plurality of excitation coils and is mounted on the main body casing 1 with each magnetic pole plate 2a facing the measuring tube 3. This is an example made. In the embodiment shown in FIGS. 27a and 27b, the excitation coil includes a pair of electrodes 41a and 41b, 42a and 42b, 43 in a plane perpendicular to the tube axis of the measuring tube.
Three pairs of 41a and 43b are arranged, and 41a is further away from the surface including the pair of electrodes in the axial direction of the measuring tube.
44a and 44 on both sides of the pair of and 41b, respectively.
b, each pair of 45a and 45b is arranged.
By making each excitation coil have a different number of turns, the magnetic flux distribution is such that the influence of the "weighting function" is reduced. Furthermore, instead of changing the number of turns, the same effect can be obtained by applying different excitation currents to each excitation coil. Furthermore, similar adjustments can be made by changing both the number of turns and the excitation current. Furthermore, as shown in FIG. 28a, which is a plan view seen from the direction of the Z arrow in FIG. Similarly, as shown in FIG. 28b, a plurality of round excitation coils 47 may be arranged around the elongated central excitation coil 46, or as shown in FIG. 28c. The magnetic field generating device can also be constructed in such a manner that a large number of round excitation coils 47 are arranged in a distributed manner.
以上詳述したように本発明によれば、磁界発生
装置を小形化することが可能になるため取付ボル
トと取付ボルトとの間に磁界発生装置を配置する
ことができて口径の大きい電磁流量計に対しても
通し形の取付ボルトを用いて電磁流量計を管路の
相手フランジ間にはさみこんで取付られる電磁流
量計を実現することができた。そして、磁極板の
形状および寸法を調整することにより磁束分布を
「重み関数」の影響を軽減する方向の分布にする
ことができて偏流の影響の少ない流量測定が可能
となつた。また、第１階微分または第２階微分が
ゼロとなる磁束を発生する磁界発生装置を用いて
いるため、本体ケーシングに磁束が流れ込んでも
性能上悪影響を及ぼす交流現象が発生しないの
で、ノイズ軽減用の成層コアを本体ケーシングの
内側に設ける必要がなくなりそれだけ本体ケーシ
ングを薄く且つ小形にすることができ、更に測定
管端以外は強磁性体製の本体ケーシングで囲まれ
た構造により面間距離も短かくすることができて
軽量化され取扱いが容易になつた。 As described in detail above, according to the present invention, it is possible to downsize the magnetic field generator, so the magnetic field generator can be disposed between the mounting bolts, and the electromagnetic flowmeter has a large diameter. We were also able to realize an electromagnetic flowmeter that can be mounted by inserting the electromagnetic flowmeter between the mating flanges of the conduit using through-type mounting bolts. By adjusting the shape and dimensions of the magnetic pole plate, the magnetic flux distribution can be made in a direction that reduces the influence of the "weighting function," making it possible to measure flow rates with less influence of drift. In addition, because it uses a magnetic field generator that generates magnetic flux with a first or second derivative of zero, even if magnetic flux flows into the main body casing, no AC phenomenon that adversely affects performance will occur, so it can be used to reduce noise. There is no need to install a layered core inside the main casing, which allows the main casing to be made thinner and smaller.Furthermore, since the main casing is surrounded by a ferromagnetic material except for the end of the measurement tube, the distance between the surfaces is shortened. This makes it lighter and easier to handle.
第１図ａ，ｂはそれぞれ本発明一実施例の電磁
流量計を示す要部切欠側面図および横断面図、第
２図は電磁流量計の重み関数の分布状態を示す説
明図、第３図は望ましい磁束密度分布を説明する
ための図、第４図は第１図の実施例における電極
を含む断面での磁束の状態を示す図、第５図は磁
極板の形状寸法を変えた場合における電極を含む
断面での磁束の状態を示す図、第６図ａ〜ｄはそ
れぞれ磁界発生装置の異なる実施態様を示す要部
断面図、第７図は本発明の別の実施例を示す要部
断面図、第８図ａ，ｂはそれぞれ磁極板の異なる
実施態様を示す断面図、第９図は本発明の更に別
の実施例を示す断面図、第１０図ａ，ｂはそれぞ
れ本発明の更に別の実施例を示す要部切欠側面図
および横断面図、第１０図ｃは第１０図ａ，ｂの
測定管の展開図、第１１図ａ，ｂ乃至第１４図
ａ，ｂはそれぞれ本発明の更に別の実施例を示す
もので、いずれもａ図は要部切欠側面図、ｂ図は
横断面図、第１５図ａ，ｂはそれぞれ本発明の更
に別の実施例を示すもので、ｂ図は正面図、ａ図
はｂ図のYY′矢視図、第１６図ａ，ｂはそれぞれ
電極の接液部の形状の異なる実施態様を示す概略
図、第１７図ａ，ｂおよび第１８回ａ，ｂはそれ
ぞれ本発明の更に別の実施例を示すもので、いず
れもａ図は要部切欠側面図、ｂ図は横断面図、第
１９図ａ乃至ｄ図はそれぞれ磁極板の先端部の平
面形状の異なる実施態様を示す概略図、第２０図
乃至第２５図はそれぞれ本発明による電磁流量計
の取付ボルトに対する対応手段の異なる実施態様
を示す概略図、第２６図は本発明の更に別の実施
例を示す断面図、第２７図ａ，ｂはそれぞれ本発
明の更に別の実施例を示す要部切欠側面図および
断面図、第２８図ａ，ｂ，ｃはそれぞれ励磁コイ
ルの配置の異なる実施態様を示す概略図である。
１……本体ケーシング、１ａ……突出部、１ｂ
……開口部、１ｄ……鏡板部、２……磁界発生装
置、２ａ……磁極板、２ｂ……継磁極、２ｃ……
鉄心、３……測定管、４……励磁コイル、５……
電極、６……蓋体、７……ライニング、２１……
カラー、２２……調整ねじ、２３……突部、２
４，２５……磁束調整棒、２６……磁気絶縁体、
２８……取付ボルト貫通用保護管、２９，３０，
３１，３２……耳状のフランジ、４０ａ，４０ｂ
……補助コイル。
Figures 1a and b are a cutaway side view and a cross-sectional view of essential parts showing an electromagnetic flowmeter according to an embodiment of the present invention, respectively; Figure 2 is an explanatory diagram showing the distribution state of the weighting function of the electromagnetic flowmeter; and Figure 3 is a diagram for explaining a desirable magnetic flux density distribution, FIG. 4 is a diagram showing the state of magnetic flux in a cross section including the electrode in the embodiment of FIG. 1, and FIG. A diagram showing the state of magnetic flux in a cross section including electrodes, FIGS. 6a to 6d are cross-sectional views of main parts showing different embodiments of the magnetic field generating device, and FIG. 7 is a main part showing another embodiment of the present invention. 8a and b are sectional views showing different embodiments of the magnetic pole plate, FIG. 9 is a sectional view showing still another embodiment of the present invention, and FIGS. 10 a and b are sectional views showing different embodiments of the magnetic pole plate, respectively. A cutaway side view and a cross-sectional view of main parts showing still another embodiment, FIG. 10c is a developed view of the measuring tube in FIGS. 10a and b, and FIGS. 11a and b to 14a and b are respectively 15A and 15B respectively show still another embodiment of the present invention; FIG. 15A is a cutaway side view of the main part, FIG. Figure B is a front view, Figure A is a view taken along the YY' arrow in Figure B, Figures 16a and b are schematic diagrams showing embodiments with different shapes of the liquid-contacted parts of the electrodes, and Figures 17a and b. 18th a and 18th b respectively show still other embodiments of the present invention, in which figure a is a cutaway side view of the main part, figure b is a cross-sectional view, and figures 19 a to d are respectively magnetic poles. FIGS. 20 to 25 are schematic diagrams showing different embodiments of the planar shape of the tip of the plate, FIGS. 27a and 27b are a cross-sectional view showing still another embodiment of the present invention, respectively, and FIGS. 28a, b, and c are respectively FIG. 6 is a schematic diagram showing different embodiments of the arrangement of excitation coils. 1...Body casing, 1a...Protrusion, 1b
...Opening portion, 1d...End plate portion, 2...Magnetic field generator, 2a...Magnetic pole plate, 2b...Regular magnetic pole, 2c...
Iron core, 3... Measuring tube, 4... Excitation coil, 5...
Electrode, 6... Lid, 7... Lining, 21...
Collar, 22...Adjustment screw, 23...Protrusion, 2
4, 25...Magnetic flux adjustment rod, 26...Magnetic insulator,
28... Protection tube for penetrating the mounting bolt, 29, 30,
31, 32... ear-shaped flange, 40a, 40b
...Auxiliary coil.
Claims (1)
る測定管を同心的に保持する強磁性体製の本体ケ
ーシングと、前記測定管にその管軸と直交する直
径軸線上に位置して配置された一対の電極と、前
記本体ケーシングに装着されこの一対の電極を結
ぶ線および前記測定管の管軸にそれぞれ磁束の中
心線が直交するように第１階微分または第２階微
分がゼロである磁束を流体に印加する少なくとも
一対の磁界発生装置とを具えた電磁流量計におい
て、 前記磁界発生装置が継磁極、鉄心、磁極板によ
つて形成され、前記鉄心に取付けられた磁極板は
測定管の外周より所定間隔隔てて測定管の一部を
覆いかつ本体ケーシングより離間して配置され、 前記磁界発生装置の励磁コイルを収納する本体
ケーシングの穴の測定管の管軸に直角な方向の穴
寸法lHと磁界発生装置の磁極板の測定管の管軸
に直角な方向の寸法lPとの関係がlP＞lHであり、
前記磁界発生装置を本件ケーシングより離して配
置することを特徴とする電磁流量計。 ２ 磁界発生装置を構成する継磁極、鉄心、磁極
板の３者が互に締結されて一体化されたことを特
徴とする特許請求の範囲第１項記載の電磁流量
計。 ３ 磁界発生装置を構成する継磁極、鉄心、磁極
板の少なくともいずれか２者の間に磁気的ギヤツ
プを設けたことを特徴とする特許請求の範囲第１
項記載の電磁流量計。 ４ 磁界発生装置の磁極板が前記装置の軸線方向
に移動可能であることを特徴とする特許請求の範
囲第１項記載の電磁流量計。 ５ 非磁性体製の測定管の励磁コイルに対向した
部分を強磁性体に置きかえ、この部分をして磁極
板の機能を兼ねさせたことを特徴とする特許請求
の範囲第１項記載の電磁流量計。 ６ 本体ケーシングの内径を測定管の内径に相当
する寸法に形成し、本体ケーシング内壁に一対の
励磁コイルの軸線上に位置させて磁極板に相当す
る断面形状を有する筒状の非磁性体製の磁気絶縁
体を貫入取着し、本体ケーシングの内壁と磁気絶
縁体と磁極板とで測定管を構成したことを特徴と
する特許請求の範囲第１項記載の電磁流量計。 ７ 本体ケーシングの相手フランジへの接続端の
少なくとも一方に取付ボトルのうちの１部のボル
トを挿通させる穴を有する耳状のフランジを設け
たことを特徴とする特許請求の範囲第１項記載の
電磁流量計。 ８ 電極の接液部が測定管内壁から管の中心方向
に突出した形状に形成されたことを特徴とする特
許請求の範囲第１項記載の電磁流量計。 ９ 磁界発生装置の磁極板が測定管の外周に沿つ
て電極の近傍まで延在した形状に形成されたこと
を特徴とする特許請求の範囲第１項記載の電磁流
量計。 １０ 一対の電極の近傍にそれぞれ互に極性の異
なる一対の補助コイルを配設したことを特徴とす
る特許請求の範囲第１項記載の電磁流量計。 １１ 磁界発生装置が複数の励磁コイルを具えて
構成させそれぞれの磁極板を測定管の外周面に対
向させて本体ケーシングに装着されたことを特徴
とする特許請求の範囲第１項記載の電磁流量計。 １２ 各励磁コイルのターン数を重み関数の影響
を軽減する如き磁束分布を生ずるようなターン数
にそれぞれ選定したことを特徴とする特許請求の
範囲第１１項記載の電磁流量計。 １３ 各励磁コイルに印加する励磁電流を重み関
数の影響を軽減する如き磁束分布を生ずるような
電流値にそれぞれ選定したことを特徴とする特許
請求の範囲第１１項記載の電磁流量計。 １４ ドラム状をなしその両端の鏡板部で流体の
通る測定管を同心的に保持する強磁性体製の本体
ケーシングと、前記測定管にその管軸と直交する
直径軸線上に位置して配置された一対の電極と、
前記本体ケーシングに装着されこの一対の電極を
結ぶ線および前記測定管の管軸にそれぞれ磁束の
中心線が直交するように第１階微分または第２階
微分がゼロである磁束を流体に印加する少なくと
も一対の磁界発生装置とを具えた電磁流量計にお
いて、前記磁界発生装置が継磁極、鉄心、磁極板
によつて形成され、前記鉄心に取付けられた磁極
板は測定管の外周より所定間隔隔てて測定管の一
部を覆いかつ本体ケーシングより離間して配置さ
れ、本体ケーシングの電極近傍位置に電極との距
離を可変に少なくとも単数配設される磁性体製の
磁束調整棒と、 前記磁界発生装置の励磁コイルを収納する本体
ケーシングの穴の測定管の管軸に直角な方向の穴
寸法lHと磁界発生装置の磁極板の測定管の管軸
に直角な方向の寸法lPとの関係がlP＞lHであり、
前記磁界発生装置を本件ケーシングより離して配
置することを特徴とする電磁流量計。 １５ 強磁性体製の磁束調整棒が一対の電磁を含
み測定管の管軸と直角な平面と本体ケーシングと
の交線の近傍位置に測定管との距離を可変に適宜
の数配設されたことを特徴とする特許請求の範囲
第１４項記載の電磁流量計。[Scope of Claims] 1. A main body casing made of a ferromagnetic material, which has a drum shape and concentrically holds a measuring tube through which a fluid passes through end plate portions at both ends thereof, and a casing on a diameter axis perpendicular to the tube axis of the measuring tube. A pair of electrodes arranged at An electromagnetic flowmeter comprising at least a pair of magnetic field generators that apply magnetic flux having a differential of zero to a fluid, wherein the magnetic field generator is formed by a relay pole, an iron core, and a magnetic pole plate, and is attached to the iron core. The magnetic pole plate covers a part of the measuring tube at a predetermined interval from the outer periphery of the measuring tube and is arranged apart from the main casing, and the tube axis of the measuring tube is located in the hole of the main casing that accommodates the excitation coil of the magnetic field generator. The relationship between the hole dimension lH in the direction perpendicular to
An electromagnetic flowmeter characterized in that the magnetic field generator is placed apart from the casing. 2. The electromagnetic flowmeter according to claim 1, characterized in that the three components of the magnetic field generating device, including a relay pole, an iron core, and a magnetic pole plate, are connected to each other and integrated. 3. Claim 1, characterized in that a magnetic gap is provided between at least any two of the relay pole, the iron core, and the magnetic pole plate constituting the magnetic field generating device.
Electromagnetic flowmeter described in section. 4. The electromagnetic flowmeter according to claim 1, wherein the magnetic pole plate of the magnetic field generating device is movable in the axial direction of the device. 5. The electromagnetic device according to claim 1, characterized in that the part of the measuring tube made of a non-magnetic material that faces the excitation coil is replaced with a ferromagnetic material, and this part also functions as a magnetic pole plate. Flowmeter. 6 The inner diameter of the main body casing is formed to a dimension corresponding to the inner diameter of the measuring tube, and a cylindrical non-magnetic material having a cross-sectional shape corresponding to the magnetic pole plate is placed on the inner wall of the main body casing on the axis of the pair of excitation coils. 2. The electromagnetic flowmeter according to claim 1, wherein a magnetic insulator is penetrated and attached, and a measurement tube is constituted by the inner wall of the main body casing, the magnetic insulator, and the magnetic pole plate. 7. The device according to claim 1, characterized in that at least one of the connecting ends of the main body casing to the mating flange is provided with an ear-shaped flange having a hole through which a bolt of one of the mounting bottles is inserted. Electromagnetic flowmeter. 8. The electromagnetic flowmeter according to claim 1, wherein the liquid contact portion of the electrode is formed in a shape protruding from the inner wall of the measuring tube toward the center of the tube. 9. The electromagnetic flowmeter according to claim 1, wherein the magnetic pole plate of the magnetic field generator is formed in a shape extending along the outer periphery of the measuring tube to the vicinity of the electrode. 10. The electromagnetic flowmeter according to claim 1, characterized in that a pair of auxiliary coils having mutually different polarities are disposed near the pair of electrodes. 11. The electromagnetic flow rate according to claim 1, wherein the magnetic field generating device is configured with a plurality of excitation coils and is mounted on the main body casing with each magnetic pole plate facing the outer peripheral surface of the measuring tube. Total. 12. The electromagnetic flowmeter according to claim 11, wherein the number of turns of each exciting coil is selected to produce a magnetic flux distribution that reduces the influence of the weighting function. 13. The electromagnetic flowmeter according to claim 11, wherein the excitation current applied to each excitation coil is selected to a current value that produces a magnetic flux distribution that reduces the influence of the weighting function. 14 A main body casing made of a ferromagnetic material, which has a drum shape and concentrically holds a measuring tube through which a fluid passes through end plate portions at both ends thereof, and a main body casing made of a ferromagnetic material that is arranged on the diameter axis perpendicular to the tube axis of the measuring tube. a pair of electrodes,
Applying a magnetic flux having a first-order differential or a second-order differential of zero to the fluid so that the center line of the magnetic flux is perpendicular to a line attached to the main body casing and connecting the pair of electrodes and the tube axis of the measuring tube. In an electromagnetic flowmeter comprising at least one pair of magnetic field generators, the magnetic field generator is formed by a relay pole, an iron core, and a magnetic pole plate, and the magnetic pole plates attached to the iron core are spaced apart from the outer periphery of the measuring tube by a predetermined interval. at least one magnetic flux adjusting rod made of a magnetic material, which covers a part of the measuring tube and is placed apart from the main casing, and is arranged near the electrode of the main casing so as to be variable in distance from the electrode; The relationship between the hole dimension lH of the hole in the main casing that houses the excitation coil of the device in the direction perpendicular to the tube axis of the measuring tube and the dimension lP of the magnetic pole plate of the magnetic field generator in the direction perpendicular to the tube axis of the measuring tube is lP. ＞lH,
An electromagnetic flowmeter characterized in that the magnetic field generator is placed apart from the casing. 15 An appropriate number of magnetic flux adjustment rods made of ferromagnetic material containing a pair of electromagnetic elements are arranged near the intersection line between the plane perpendicular to the tube axis of the measuring tube and the main casing, with the distance from the measuring tube being variable. An electromagnetic flowmeter according to claim 14, characterized in that:
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56164258A JPS5866017A (en) | 1981-10-16 | 1981-10-16 | Electromagnetic flowmeter |
| US06/394,304 US4470309A (en) | 1981-07-06 | 1982-07-01 | Electromagnetic flowmeter |
| GB08219345A GB2103370B (en) | 1981-07-06 | 1982-07-05 | Electromagnetic flowmeter |
| FR8211854A FR2509043B1 (en) | 1981-07-06 | 1982-07-06 | ELECTROMAGNETIC FLOW METER |
| DE19823225226 DE3225226A1 (en) | 1981-07-06 | 1982-07-06 | ELECTROMAGNETIC FLOW METER |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56164258A JPS5866017A (en) | 1981-10-16 | 1981-10-16 | Electromagnetic flowmeter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5866017A JPS5866017A (en) | 1983-04-20 |
| JPH0432327B2 true JPH0432327B2 (en) | 1992-05-29 |
Family
ID=15789671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56164258A Granted JPS5866017A (en) | 1981-07-06 | 1981-10-16 | Electromagnetic flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5866017A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016527496A (en) * | 2013-07-19 | 2016-09-08 | ローズマウント インコーポレイテッド | Magnetic flow meter |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61228311A (en) * | 1985-04-03 | 1986-10-11 | Hitachi Ltd | Detector of electromagnetic flowmeter |
| JPH0695029B2 (en) * | 1986-01-08 | 1994-11-24 | 株式会社日立製作所 | Electromagnetic flow meter |
| JP5818415B2 (en) * | 2010-08-30 | 2015-11-18 | 株式会社東芝 | Calibration device for electromagnetic flow measurement system |
| JP2015105929A (en) * | 2013-12-02 | 2015-06-08 | 株式会社東芝 | Electromagnetic flow meter |
| GB201818890D0 (en) * | 2018-11-20 | 2019-01-02 | Ind Tomography Systems Plc | Mass flow monitoring |
| DE102019123413A1 (en) * | 2019-09-02 | 2021-03-04 | Endress+Hauser Flowtec Ag | Electromagnetic flow meter |
-
1981
- 1981-10-16 JP JP56164258A patent/JPS5866017A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016527496A (en) * | 2013-07-19 | 2016-09-08 | ローズマウント インコーポレイテッド | Magnetic flow meter |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5866017A (en) | 1983-04-20 |
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