JP2801849B2 - Coriolis flow meter - Google Patents
Coriolis flow meterInfo
- Publication number
- JP2801849B2 JP2801849B2 JP21842693A JP21842693A JP2801849B2 JP 2801849 B2 JP2801849 B2 JP 2801849B2 JP 21842693 A JP21842693 A JP 21842693A JP 21842693 A JP21842693 A JP 21842693A JP 2801849 B2 JP2801849 B2 JP 2801849B2
- Authority
- JP
- Japan
- Prior art keywords
- tube
- electromagnet
- counterbalance
- fixed
- measuring tube
- 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
Description
【０００１】[0001]
【技術分野】本発明は、コリオリ流量計に関し、より詳
細には、カウンタバランス方式のコリオリ流量計および
駆動手段に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Coriolis flowmeter, and more particularly, to a counterbalance type Coriolis flowmeter and driving means.
【０００２】[0002]
【従来技術】測定管を両端で支持し、支持された測定管
の中央部を軸線に垂直な方向に交番駆動している時、流
体が移動すると、測定管の中央部を中心として、測定管
の流入側と流出側に位相差が生ずる。この位相差は、コ
リオリの力に基づくもので、質量流量に比例した値であ
り、前記位相差を検知して質量流量を計測するコリオリ
流量計は周知である。2. Description of the Related Art When a fluid moves when a measuring tube is supported at both ends and a central portion of the supported measuring tube is alternately driven in a direction perpendicular to an axis, the measuring tube is centered on the central portion of the measuring tube. A phase difference is generated between the inflow side and the outflow side of the. This phase difference is based on the Coriolis force and is a value proportional to the mass flow rate. Coriolis flow meters that detect the phase difference and measure the mass flow rate are well known.
【０００３】上述のごとく、コリオリ流量計は、両端支
持された測定管を駆動するための駆動手段を有し、通
常、駆動エネルギを最小とする測定管の固有振動数で駆
動される。このため、測定管と駆動手段と測定管の振幅
を検出するセンサ（コリオリ力の検出と共用される）
と、センサ信号を増幅し駆動手段を駆動する増幅回路と
で正帰還ループを形成して振幅一定となるように駆動さ
れる。As described above, a Coriolis flowmeter has a driving means for driving a measuring tube supported at both ends, and is usually driven at a natural frequency of the measuring tube which minimizes driving energy. For this reason, the sensor for detecting the amplitude of the measuring tube, the driving means, and the measuring tube (shared with the detection of Coriolis force)
And an amplifier circuit that amplifies the sensor signal and drives the driving means, forms a positive feedback loop, and is driven to have a constant amplitude.
【０００４】駆動手段は、例えば、電磁コイルとコアと
からなり、電磁コイルに交流電源を印加してコアを交番
吸引する電磁力を利用している。これらの駆動手段の電
磁コイルとコアとは各々、固定された基板と、該基板上
に両端支持された測定管とに装着される。しかし、測定
管をより効率よく駆動するために、上記基板の替りに、
測定管の固有振動数と等しい固有振動数を有する管体や
柱体又は板状体等の振動体（カウンタバランス）を用い
て、カウンタバランスを測定管と平行に支持体に支持
し、駆動手段をカウンタバランスと測定管との間に装着
して、カウンタバランスと測定管とを音叉（チューニン
グホーク）状に駆動する。このようなカウンタバランス
の構造は測定管の形状に応じて定められる。The driving means includes, for example, an electromagnetic coil and a core, and utilizes an electromagnetic force for applying an AC power to the electromagnetic coil to alternately attract the core. The electromagnetic coil and the core of these driving means are respectively mounted on a fixed substrate and a measuring tube supported on both ends of the substrate. However, in order to drive the measuring tube more efficiently, instead of the substrate,
Using a vibrating body (counter balance) such as a tube, a column, or a plate having a natural frequency equal to the natural frequency of the measuring tube, the counter balance is supported by the support in parallel with the measuring tube, and the driving means Is mounted between the counterbalance and the measuring tube, and the counterbalance and the measuring tube are driven in a tuning fork (tuning fork) shape. The structure of such a counterbalance is determined according to the shape of the measuring tube.
【０００５】図４は、従来の直管形のカウンタバランス
管構造をもったコリオリ流量計の一例を示す図であり、
測定流体が流れる流管（図示せず）と接続される円筒状
の外筒２３を有し、外筒２３内には、外筒２３と同軸に
両端が接続された直管状の測定管２１と、該測定管２１
と同軸で大径のカウンタバランス管２２の両端とが固着
されており、測定管２１とカウンタバランス管２２との
中間部には鉄芯２４ａと電磁コイル２４ｂとからなる電
磁加振器２４が配設され、加振により測定管２１に生じ
たコリオリの力による位相変位を変位センサ２５，２６
で検出している。FIG. 4 is a view showing an example of a conventional Coriolis flowmeter having a straight pipe counterbalance pipe structure.
It has a cylindrical outer tube 23 connected to a flow tube (not shown) through which a measurement fluid flows. Inside the outer tube 23, there is a straight tube-shaped measurement tube 21 coaxially connected to the outer tube 23 at both ends. , The measuring tube 21
The two ends of a large-diameter counterbalance tube 22 which are coaxial with each other are fixed, and an electromagnetic exciter 24 composed of an iron core 24a and an electromagnetic coil 24b is disposed at an intermediate portion between the measurement tube 21 and the counterbalance tube 22. And the phase displacement due to Coriolis force generated in the measuring tube 21 by the vibration is applied to the displacement sensors 25 and 26.
Detected by.
【０００６】この構造では、測定管２１とカウンタバラ
ンス管２２との固有振動数が異なりチューニングホーク
状の駆動ができないので、例えば、カウンタバランス管
２２の中央に重錘２７を取り付けて両者の固有振動数を
等しくしている。In this structure, since the natural frequencies of the measuring tube 21 and the counterbalance tube 22 are different and the tuning fork-like drive cannot be performed, for example, the weight 27 is attached to the center of the counterbalance tube 22 and The numbers are equal.
【０００７】図５は、従来の湾曲形のカウンタバランス
駆動構造をもったコリオリ流量計の一例を示す斜視図で
あり、支持板３３をＹ−Ｙ線上に貫通しＸ−Ｘ軸に軸対
称に両腕部を固着された測定管３１と、測定管３１と同
形で測定管３１と平行に支持部３３に固着されたカウン
タバランス管３２を有し、測定管３１とカウンタバラン
ス管３２とは所定条件でＹ−Ｙ軸方向に関し等しい固有
振動数をもっている。加振器３４は、Ｘ−Ｘ軸上の測定
管３１とカウンタバランス管３２との間に配設され、同
様に、センサ３５、３６はＸ−Ｘ軸と軸対称位置に配設
され、図４における前述と同様な動作がなされる。FIG. 5 is a perspective view showing an example of a conventional Coriolis flowmeter having a curved counterbalance drive structure. The Coriolis flowmeter penetrates the support plate 33 along the line YY and is axially symmetric with respect to the XX axis. A measuring tube 31 having both arms fixed thereto, and a counterbalance tube 32 having the same shape as the measuring tube 31 and being fixed to the support portion 33 in parallel with the measuring tube 31, wherein the measuring tube 31 and the counterbalance tube 32 are predetermined. Under the condition, they have the same natural frequency in the YY axis direction. The vibrator 34 is disposed between the measuring tube 31 and the counterbalance tube 32 on the XX axis, and similarly, the sensors 35 and 36 are disposed at positions symmetrical with the XX axis. 4, the same operation as described above is performed.
【０００８】図６は従来の一般的な直管方式のカウンタ
バランス方式のコリオリ流量計の構造を示す図で、図に
おいて、測定管４０は、配管に対しフランジ４０ａ、４
０ｂで接続され、両端近傍に枠体４１が固着されてい
る。枠体４１内の測定管４０には、測定管４０を貫通固
着された支持板４２、４３が所定間隔を隔てて配設さ
れ、支持板４２、４３には流体が流れないカウンタバラ
ンス管４７が測定管４０と平行に固着されている。加振
器４４は測定管４０の中央にカウンタバランス管４７と
の間に固着されており、センサ４５、４６も同様に加振
器４４に関し対称位置に固着されている。しかし、コリ
オリ流量計は、目的に応じた種類の流体の流量を測定す
るものであるから、測定管には各種の測定流体が流れ
る。この結果、両端支持された測定管の固有振動数は、
測定流体の密度に応じて変化する。また、同一流体であ
っても、測定流体の温度に応じて密度が変化し固有振動
数が変化する。しかし、図４、図５、図６に示した測定
流体が流れないカウンタバランス管２２、３２、４７の
固有振動数は一定であり、測定管２１、３１、４０の固
有振動数との間に固有振動数の差が生じ、効率のよい駆
動することができず、しかも、コリオリの力による測定
管の変位量が変化し高精度な流量検出ができなくなると
いう問題があった。FIG. 6 is a view showing the structure of a conventional general straight pipe counter-balance type Coriolis flowmeter. In FIG.
0b, and a frame 41 is fixed near both ends. Support plates 42 and 43 penetrating and fixing the measurement tube 40 are disposed at predetermined intervals in the measurement tube 40 in the frame 41, and a counter balance tube 47 in which fluid does not flow through the support plates 42 and 43. It is fixed in parallel with the measuring tube 40. The vibrator 44 is fixed at the center of the measuring tube 40 between the vibrator 44 and the counter balance tube 47, and the sensors 45 and 46 are similarly fixed at symmetric positions with respect to the vibrator 44. However, since the Coriolis flowmeter measures the flow rate of a fluid of a type suitable for the purpose, various types of measurement fluid flow through the measurement tube. As a result, the natural frequency of the measurement tube supported at both ends is
It changes according to the density of the measurement fluid. Further, even for the same fluid, the density changes and the natural frequency changes in accordance with the temperature of the measurement fluid. However, the natural frequencies of the counterbalance pipes 22, 32, and 47 in which the measurement fluid does not flow shown in FIGS. 4, 5, and 6 are constant, and are different from the natural frequencies of the measurement pipes 21, 31, and 40. There is a problem that a difference in natural frequency occurs, and efficient driving cannot be performed, and furthermore, the amount of displacement of the measuring tube due to the Coriolis force changes, making it impossible to detect flow rate with high accuracy.
【０００９】[0009]
【目的】本発明は、上述の実情に鑑みてなされたもの
で、測定管内を流れる流体の密度が変化し、測定管の固
有振動数が変化しても、カウンタバランス管の固有振動
数が、測定管の固有振動数と等しくなるように制御して
高精度で安定した駆動ができるコリオリ流量計を提供す
ることを目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and even if the density of a fluid flowing in a measurement tube changes and the natural frequency of the measurement tube changes, the natural frequency of the counterbalance tube is changed. It is an object of the present invention to provide a Coriolis flowmeter that can be controlled to be equal to the natural frequency of a measurement tube and can be driven with high accuracy and stability.
【００１０】[0010]
【構成】本発明は、上記目的を達成するために、（１）
支持部材と、該支持部材に両端が支持され測定流体が流
れる測定管と、両端が前記支持部材に支持されるカウン
タバランス管と、該カウンタバランス管と測定管とに配
設され該測定管を長手方向に対して直角方向に駆動する
加振器と、前記測定管に作用するコリオリの力に応じ該
測定管と前記カウンタバランス管との所定２地点の間に
生ずる変位を検知する一対のセンサとを有し、該一対の
センサの位相差に比例した質量流量を出力するコリオリ
流量計において、前記加振器の加振エネルギを検知する
加振エネルギ検知手段と、前記測定管またはカウンタバ
ランスの中央部に重錘を懸架固着する重錘装着手段と、
該重錘装着手段を駆動し、前記加振エネルギ検知手段に
より検知された検知エネルギを最低とする重錘を前記測
定管又はカウンタバランスを固着するウエイト制御部と
からなること。更には、（２）前記（１）において、重
鐘装着手段を、カウンタバランス管の軸と直角で該カウ
ンタバランス管外壁に一端が固着された磁性材の磁石支
持柱と、該磁石支持柱を軸方向複数に区分した各々の断
面上該磁石支持柱を挾んだ対称位置に前記支持部材に固
着された複数の駆動磁石と、前記磁石支持柱と複数の各
々の駆動磁石との間に分割配設され、常時磁力により前
記前記磁石支持柱に吸引固着される重錘であり前記駆動
磁石の駆動により前記支持柱の固着を解き駆動磁石側に
磁気吸引される複数対の半環状磁性板とから構成したこ
と。更には、（３）前記（１）において、重錘装着手段
を、カウンタバランス管外壁面に固着された第１電磁石
と、該第１電磁石と所定間隔を隔て対向し支持部材に固
着された第２電磁石と、前記第１電磁石と第２電磁石と
の間に配設され重錘となる複数の磁性板とからなり、前
記第１電磁石と第２電磁石とに印加する電流差に基づい
て前記第１電磁石に磁気吸引される磁性板の数を可変と
する。更には、（４）前記（３）において、前記磁性板
を磁性粉としたことを特徴とする請求項３記載のコリオ
リ流量計を特徴とするものである。以下、本発明の実施
例に基づいて説明する。To achieve the above object, the present invention provides (1)
A support member, a measurement tube having both ends supported by the support member and through which a measurement fluid flows, a counter balance tube having both ends supported by the support member, and the measurement tube disposed on the counter balance tube and the measurement tube. A pair of sensors for detecting a displacement generated between two predetermined points of the measuring tube and the counterbalance tube in response to a Coriolis force acting on the measuring tube; A Coriolis flowmeter that outputs a mass flow rate proportional to the phase difference between the pair of sensors, wherein a vibration energy detecting means for detecting vibration energy of the vibrator; Weight mounting means for suspending and fixing the weight at the center,
A weight control unit that drives the weight mounting means and fixes the weight that minimizes the detection energy detected by the excitation energy detection means to the measurement tube or the counterbalance. (2) In the above (1), the double bell mounting means may be a magnet support column made of a magnetic material having one end fixed to the outer wall of the counter balance tube at right angles to the axis of the counter balance tube, and A plurality of driving magnets fixed to the support member at symmetrical positions sandwiching the magnet supporting column on each of a plurality of sections divided in the axial direction, and a plurality of driving magnets divided into the magnet supporting column and the plurality of driving magnets; A plurality of pairs of semi-circular magnetic plates that are disposed and are always attracted and fixed to the magnet support columns by magnetic force, and the driving magnets release the fixation of the support columns and are magnetically attracted to the drive magnet side. It was composed from. (3) In the above (1), the weight mounting means may include a first electromagnet fixed to the outer wall surface of the counterbalance pipe, and a first electromagnet fixed to the support member facing the first electromagnet at a predetermined interval. A second electromagnet, and a plurality of magnetic plates disposed between the first electromagnet and the second electromagnet and serving as a weight. The second electromagnet is configured based on a current difference applied to the first electromagnet and the second electromagnet. The number of magnetic plates magnetically attracted to one electromagnet is made variable. (4) The Coriolis flowmeter according to claim 3, wherein in (3), the magnetic plate is made of magnetic powder. Hereinafter, a description will be given based on examples of the present invention.
【００１１】図１（ａ），（ｂ）は本発明によるコリオ
リ流量計の構造の一例を説明するための部分図である。
図１（ａ）はコリオリ流量計の要部断面図、図１（ｂ）
は，図１（ａ）の矢視Ｂ−Ｂ断面図で、図中、１は測定
管、２はカウンタバランス管、３は加振器、４は磁石支
持柱、、５ａ，５ｂは半環状磁性板、６ａ，６ｂは駆動
磁石、７ａ，７ｂは案内具、８はウエスト制御部、９は
加振電流検出器、１０は支持部材、１１は重錘装着手段
である。FIGS. 1A and 1B are partial views for explaining an example of the structure of a Coriolis flow meter according to the present invention.
FIG. 1A is a sectional view of a main part of a Coriolis flow meter, and FIG.
Is a sectional view taken along the line BB in FIG. 1 (a), where 1 is a measuring tube, 2 is a counterbalance tube, 3 is a vibrator, 4 is a magnet support column, and 5a and 5b are semi-annular. A magnetic plate, 6a and 6b are driving magnets, 7a and 7b are guides, 8 is a waist control unit, 9 is a vibration current detector, 10 is a support member, and 11 is a weight mounting means.
【００１２】測定管１とカウンタバランス管２とは同軸
で、支持部材９である支持筒（図示せず）内に両端部で
支持されている。測定管１とカウンタバランス管２との
中央部には、各々鉄芯３ａ、コイル３ｂとからなる加振
器３が取り付けられ、さらに、加振器３の両側対称位置
には変位のセンサ（図示せず）が取り付けられている。The measuring tube 1 and the counterbalance tube 2 are coaxial, and are supported at both ends in a supporting cylinder (not shown) which is a supporting member 9. A vibrator 3 composed of an iron core 3a and a coil 3b is attached to a central portion of the measuring tube 1 and the counterbalance tube 2, and a displacement sensor (see FIG. (Not shown).
【００１３】加振器３と反対側のカウンタバランス管２
の中央部壁面Ｐと支持部１０との間には重錘装着手段１
１が取り付けられれている。重錘装着手段１１は、磁石
支持柱４と、複数の対をなす半環状磁性板５ａ，５ｂ
と、複数の対をなす駆動磁石６ａ６ｂからなり、ウエイ
ト制御部８と加振電流検出器９とにより駆動される。磁
石支持柱４は、半環状磁性板５ａ，５ｂの厚さに対応し
た幅で、軸方向に区分された永久磁石、電磁石、あるい
は高透磁率のパーマロイ等の磁性材からなる柱状体で、
一端がカウンタバランス２の外周壁の中央部Ｐ位置に固
着され、他端は自由端となっている。半環状磁性板５
ａ，５ｂは、内周壁が磁石支持柱４の外周と等しい内径
を有する環状の強磁性板又は磁石板を直径方向に略２分
し、重錘となるもので、磁石支持柱４を軸方向に複数区
分した区分毎に一対となり、区分の数だけの対５ａ，５
ｂ；５ａ2，５ｂ2…（複雑となるため番号は付せず）を
もっている。The counter balance tube 2 on the side opposite to the vibrator 3
Weight mounting means 1 between the central wall surface P and the support portion 10
1 is attached. The weight mounting means 11 comprises a plurality of pairs of semi-annular magnetic plates 5a, 5b
And a plurality of pairs of drive magnets 6 a and 6 b, which are driven by the weight control unit 8 and the excitation current detector 9. The magnet support column 4 is a columnar body made of a magnetic material such as a permanent magnet, an electromagnet, or a high magnetic permeability permalloy having a width corresponding to the thickness of the semi-annular magnetic plates 5a and 5b and divided in the axial direction.
One end is fixed to the central portion P of the outer peripheral wall of the counter balance 2, and the other end is a free end. Semi-circular magnetic plate 5
Reference numerals a and 5b each denote an annular ferromagnetic plate or a magnet plate having an inner peripheral wall having an inner diameter equal to the outer periphery of the magnet support column 4 in a diametrical direction by approximately two and serving as a weight. Are paired for each of the plurality of sections, and pairs 5a, 5
b; 5a 2 , 5b 2 ... (numbers are not given due to complexity).
【００１４】駆動磁石６ａ、６ｂは、例えば、電磁石か
らなり支持部９である支持筒内壁に固着され、半環状磁
性板５ａ，５ｂの対の数だけあるウエイト制御部８の指
令により、各々の半環状磁性板５ａ，５ｂに対応して磁
石支持柱４の軸方向に図中１、２、３、４、５で示すよ
うに配設され、該半環状磁性板５ａ，５ｂを吸着した
り、又は、反発磁極を形成して磁石支持柱４に磁気吸引
させる。このように、半環状磁性板５ａ，５ｂは、ウエ
イト制御部８の指令により駆動磁石５ａ，５ｂ側と磁石
支持柱４との間で吸着と離間を繰り返す。このときの半
環状磁性板５ａ，５ｂは、定められた直径方向の軌跡に
従って移動するが、必要に応じて案内具７ａ，７ｂを配
設して周方向の移動を防止できる。The drive magnets 6a and 6b are made of, for example, electromagnets and are fixed to the inner wall of the support cylinder, which is a support portion 9, and each of the drive magnets 6a and 6b is instructed by a weight control portion 8 corresponding to the number of pairs of semi-circular magnetic plates 5a and 5b. In the figure, reference numerals 1, 2, 3, 4, and 5 are provided in the axial direction of the magnet support columns 4 corresponding to the semi-annular magnetic plates 5a and 5b to attract the semi-annular magnetic plates 5a and 5b. Alternatively, a repulsive magnetic pole is formed and the magnet support column 4 is magnetically attracted. As described above, the semi-annular magnetic plates 5 a and 5 b repeat attraction and separation between the drive magnets 5 a and 5 b and the magnet support column 4 in accordance with a command from the weight controller 8. At this time, the semi-annular magnetic plates 5a and 5b move according to a predetermined trajectory in the diameter direction. However, if necessary, guides 7a and 7b can be arranged to prevent the movement in the circumferential direction.
【００１５】前述の如く、カウンタバランス方式の駆動
は測定管１の一方側の変位センサ（図示せず）の信号を
検出して、加振器３のコイル３ｂを測定管１の振幅が一
定となるように正帰還駆動する増幅回路に含まれる回路
部分をなすものであり、測定管１の固有振動数ｆMとカ
ウンタバランス管２の固有振動数ｆsとが等しいｆM=ｆs
のチューニングフォークの状態で駆動電流即ち駆動エネ
ルギーが最小になる。逆に、固有振動数が異なりｆM≠
ｆsの場合は駆動効率が悪くなり駆動電流が大きくな
る。加振電流検出器９は、この電流を検出する回路であ
る。一方、カウンタバランス管２および測定管１は、支
持部材に両端を固着されているので、各々の長さは等し
い。この状態でのカウンタバランス管２のばね定数をＫ
s'質量をＭs'とし、測定管１のばね定数をＫM'、質量を
ＭM'測定管５内に収容された測定流体の質量をＭLとす
ると、As described above, in the counterbalance driving, a signal from a displacement sensor (not shown) on one side of the measuring tube 1 is detected, and the coil 3b of the vibrator 3 is turned on when the amplitude of the measuring tube 1 is constant. And a circuit part included in the amplifier circuit driven by positive feedback so that the natural frequency f M of the measuring tube 1 is equal to the natural frequency f s of the counter balance tube 2. F M = fs
In the state of the tuning fork, the driving current, that is, the driving energy is minimized. Conversely, the natural frequencies are different and f M ≠
In the case of fs, the driving efficiency is deteriorated and the driving current is increased. The excitation current detector 9 is a circuit that detects this current. On the other hand, both ends of the counterbalance tube 2 and the measurement tube 1 are equal to each other because both ends are fixed to the support member. In this state, the spring constant of the counterbalance tube 2 is represented by K
'Mass Ms' s and, the spring constant K M measuring tube 1 mass measurement fluid ', mass M M' is housed in the measuring pipe 5 When M L,
【００１６】[0016]
【数１】 (Equation 1)
【００１７】であらわされるが一般的には、（Ｋs/Ｍs)
＞（ＫM/ＭM+ＭL)であるから、 ｆs＞ｆM …(3) でカウンタバランス管２の固有振動数ｆsは測定管1の固
有振動数ｆMよりも大きい。従って、本発明では、駆動
電流が最小となるようにカウンタバランス管２に重錘を
付加し、カウンタバランス管２の固有振動数ｆsと測定
管１の固有振動数ｆMとを略等しくｆs≒ｆMとなるよう
にする。In general, (Ks / Ms)
> Because it is (K M / M M + M L), fs> f M ... (3) the natural frequency fs of the counterbalancing tube 2 is greater than the natural frequency f M of the measurement pipe 1. Accordingly, the present invention adds a weight to the counterbalance tube 2 so that the drive current is minimized, substantially equal fs ≒ the counterbalance tube 2 and the natural frequency fs and natural frequency f M of the measurement pipe 1 f M.
【００１８】ウエイト制御部８には駆動順序回路が組込
まれており加振電流検出器９の検出信号に基づいて駆動
磁石６ａ，６ｂを順次ＯＮ−ＯＦＦ駆動する。例えば、
ＯＦＦ時には半環状磁石５ａ，５ｂと駆動磁石６ａ，６
ｂとは反撥磁場を形成して半環状磁石５ａ，５ｂを磁石
支持柱４側に固着して質量Ｍsを増加させることにより
固定振動数ｆsを下げ、ＯＮ時には逆に駆動磁石６ａ，
６ｂ側に固着されることにより質量Ｍsを減少させｆsを
増加させる。A driving sequence circuit is incorporated in the weight control unit 8, and the driving magnets 6a and 6b are sequentially turned on and off based on a detection signal of the excitation current detector 9. For example,
When turned off, the semi-annular magnets 5a, 5b and the drive magnets 6a, 6
The fixed frequency fs is reduced by forming a repulsive magnetic field and fixing the semi-annular magnets 5a and 5b to the magnet support column 4 side to increase the mass Ms.
By fixing to the 6b side, the mass Ms is reduced and fs is increased.
【００１９】図２は、本発明によるコリオリ流量計の、
他の実施例を説明するための部分図で、図中、１２、１
３は電磁石、１４は磁性板であり、図１と同じ作用をす
る部分には図１と同一の参照番号を付している。電磁石
１２は、カウンタバランス管２の中央外壁面に固着さ
れ、電磁石１３は電磁石１２と対向し支持部材９に固着
され、電磁石１２と１３とは反対向きの磁極となるよう
に各々電流ｉ1，ｉ2で駆動されている。更に、電磁石１
２と電磁石１３との間には複数の磁性板１４が配設され
電磁石１２と電磁石１３とに磁気吸引される。磁性板１
４は、電磁石１２に印加される電流ｉ1の大きさと、電
磁石１３に印加される電流ｉ2の大きさの磁場の強さに
従って吸着枚数が定められ、質量Ｍ1，Ｍ2が規定され
る。磁性板１４の吸着枚数が電磁石１２側が増加する方
向では質量Ｍ1が増加、固有振動数ｆsは低下し吸着枚数
が減少すると、質量Ｍ1が減少し、固有振動数ｆsは増大
する。このときの電磁石１２、１３の駆動電流ｉ1，ｉ2
の大きさは、加振電流検出器９の信号に従って定められ
ている。FIG. 2 shows a Coriolis flow meter according to the invention.
FIG. 13 is a partial view for explaining another embodiment,
Reference numeral 3 denotes an electromagnet, and 14 denotes a magnetic plate. Parts having the same functions as in FIG. 1 are denoted by the same reference numerals as in FIG. The electromagnet 12 is fixed to the center outer wall surface of the counterbalance tube 2, and the electromagnet 13 is fixed to the support member 9 facing the electromagnet 12, and the currents i 1 , It is driven by i 2. Further, the electromagnet 1
A plurality of magnetic plates 14 are provided between the magnet 2 and the electromagnet 13, and the magnetic plates 14 are magnetically attracted to the electromagnet 12 and the electromagnet 13. Magnetic plate 1
4, the magnitude of the current i 1 applied to the electromagnet 12, the adsorption number is defined in accordance with the strength of the magnetic field of the magnitude of the current i 2 that is applied to the electromagnet 13, the mass M 1, M 2 is defined . Adsorption number of the magnetic plate 14 is mass M 1 is increased in the direction of electromagnet 12 side is increased, the inherent frequency of fs decreased adsorption number is reduced, decreased mass M 1 is, the natural frequency fs is increased. The driving currents i 1 and i 2 of the electromagnets 12 and 13 at this time
Is determined according to the signal of the excitation current detector 9.
【００２０】図３は、本発明によるコリオリ流量計の、
他の実施例を説明するための部分図であり、図中、１５
は磁性粉で、図１、２と同じ作用をする部分には、図
１、２と同一の参照番号を付している。図３の磁性粉１
５は、鉄、パーマロイ等の微粉体であり図２に示した磁
性板１４と同様の作用を有し、加振電流検出器９に基づ
いて、互いに反対磁極に励磁された電磁石１２、１３に
印加する電流ｉ1，ｉ2の大きさが定められる。この結
果、カウンタバランス管２側に付着する磁性粉１５の量
は電流ｉ1，ｉ2の大きさに従った質量Ｍ1となり、質量
Ｍ1に基づいて連続時にカウンタバランス管２の固有振
動数が定められる。以上の説明では図４に示した直管式
のカウンタバランス方式のコリオリ流量計について説明
したが、図５、６に示した湾曲管のカウンタバランス方
式のコリオリ流量にも適用できる。FIG. 3 shows a Coriolis flow meter according to the invention.
FIG. 14 is a partial view for explaining another embodiment, in which 15
Is a magnetic powder, and the portions having the same functions as those in FIGS. 1 and 2 are denoted by the same reference numerals as those in FIGS. Magnetic powder 1 of FIG.
Numeral 5 is a fine powder of iron, permalloy, or the like, which has the same function as the magnetic plate 14 shown in FIG. The magnitudes of the applied currents i 1 and i 2 are determined. As a result, the amount of the magnetic powder 15 adhering to the counter balance tube 2 becomes a mass M 1 according to the magnitude of the currents i 1 and i 2 , and the natural frequency of the counter balance tube 2 is continuously determined based on the mass M 1. Is determined. In the above description, the straight tube counter-balanced Coriolis flowmeter shown in FIG. 4 has been described. However, the present invention can also be applied to the curved tube counterbalanced Coriolis flowmeter shown in FIGS.
【００２１】[0021]
【発明の効果】以上の説明から明らかなように、本発明
によると、カウンタバランス方式のコリオリ流量計にお
いて、測定流体の密度が変化して測定管の固有振動数が
変化した場合でも、所定の重錘を固着することにより、
カウンタバランス管の固有振動数を測定管の固有振動数
に略一致させることができる。この結果、コリオリの力
により変化する測定管の変化測定が常に一定条件で行わ
れるので測定精度が向上し、しかも効率のよい測定条件
が得られる。As is apparent from the above description, according to the present invention, in the counter-balanced Coriolis flowmeter, even if the density of the measurement fluid changes and the natural frequency of the measurement tube changes, a predetermined value can be obtained. By fixing the weight,
The natural frequency of the counterbalance tube can be made to substantially match the natural frequency of the measurement tube. As a result, the measurement of the change of the measuring tube, which changes due to the Coriolis force, is always performed under constant conditions, so that the measurement accuracy is improved and more efficient measurement conditions are obtained.
【図１】本発明によるコリオリ流量計の構造を説明する
ための部分図である。FIG. 1 is a partial view for explaining the structure of a Coriolis flow meter according to the present invention.
【図２】本発明によるオリオリ流量計の他の実施例を説
明するための部分図である。FIG. 2 is a partial view for explaining another embodiment of the flow meter according to the present invention.
【図３】本発明によるコリオリ流量計の他の実施例を説
明するための部分図である。FIG. 3 is a partial view for explaining another embodiment of a Coriolis flow meter according to the present invention.
【図４】従来の直管桂のカウンタバランス駆動構造をも
ったコリオリ流量計の一例を示す図である。FIG. 4 is a diagram showing an example of a conventional Coriolis flowmeter having a straight pipe counterbalance drive structure.
【図５】従来の湾曲形のカウンタバランス駆動構造をも
ったコリオリ流量計の一例を示す斜視図である。FIG. 5 is a perspective view showing an example of a conventional Coriolis flowmeter having a curved counterbalance drive structure.
【図６】従来の直管方式のカウンタバランス方式のコリ
オリ流量計の構造を示す図である。FIG. 6 is a view showing the structure of a conventional straight pipe counter-balanced Coriolis flowmeter.
１…測定管、２…カウンタバランス管、３…加振器、４
…磁石支持柱、５ａ，５ｂ…半環状磁性板、６ａ，６ｂ
…駆動磁石、７ａ，７ｂ…案内具、８…ウエイト制御
部、９…加振電流検知部、１０…支持部材、１１…重錘
装着手段、１２、１３…電磁石、１４…磁性板、１５…
磁性粉。DESCRIPTION OF SYMBOLS 1 ... Measurement pipe, 2 ... Counter balance pipe, 3 ... Exciter, 4
... Magnet support columns, 5a, 5b ... Semi-annular magnetic plates, 6a, 6b
... Driving magnets, 7a, 7b Guide, 8 ... Weight control unit, 9 ... Exciting current detection unit, 10 ... Support member, 11 ... Weight mounting means, 12, 13 ... Electromagnet, 14 ... Magnetic plate, 15 ...
Magnetic powder.
フロントページの続き (56)参考文献 特開 平５−248913（ＪＰ，Ａ) 特開 平６−94501（ＪＰ，Ａ) 特開 平３−41319（ＪＰ，Ａ) 特開 平６−160148（ＪＰ，Ａ) 特開 平５−248913（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01F 1/84Continuation of front page (56) References JP-A-5-248913 (JP, A) JP-A-6-94501 (JP, A) JP-A-3-41319 (JP, A) JP-A-6-160148 (JP) , A) JP-A-5-248913 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) G01F 1/84
Claims (4)
れ測定流体が流れる測定管と、両端が前記支持部材に支
持されるカウンタバランス管と、該カウンタバランス管
と測定管とに配設され該測定管を長手方向に対して直角
方向に駆動する加振器と、前記測定管に作用するコリオ
リの力に応じ該測定管と前記カウンタバランス管との所
定の２地点の間に生ずる変位を検知する一対のセンサと
を有し、該一対のセンサの出力差に比例した質量流量を
出力するコリオリ流量計において、前記加振器の加振エ
ネルギを検知する加振エネルギ検知手段と、前記測定管
またはカウンタバランスの中央部に重錘を懸架固着する
重錘装着手段と、該重錘装着手段を駆動し、前記加振エ
ネルギ検知手段により検知された検知エネルギを最小と
するように重錘を前記測定管又はカウンタバランスに固
着するウエイト制御部とからなることを特徴とするコリ
オリ流量計。1. A support member, a measurement tube having both ends supported by the support member and through which a measurement fluid flows, a counter balance tube having both ends supported by the support member, and a counter balance tube and a measurement tube are provided. A vibrator for driving the measuring tube in a direction perpendicular to the longitudinal direction, and a displacement generated between two predetermined points of the measuring tube and the counterbalance tube in response to Coriolis force acting on the measuring tube. In a Coriolis flowmeter that has a pair of sensors for detecting a vibration and outputs a mass flow rate proportional to an output difference between the pair of sensors, a vibration energy detecting unit that detects vibration energy of the vibrator; Weight mounting means for suspending and fixing the weight at the center of the measuring tube or the counterbalance; and a weight for driving the weight mounting means and minimizing the detected energy detected by the excitation energy detecting means. Before A Coriolis flowmeter, comprising: a measuring tube or a weight controller fixed to a counterbalance.
軸と直角で該カウンタバランス管外壁に一端が固着され
た磁性材の磁石支持柱と、該磁石支持柱を軸方向複数に
区分した各々の断面上該磁石支持柱を挾んだ対称位置に
前記支持部材に固着された複数の駆動磁石と、前記磁石
支持柱と複数の各々の駆動磁石との間に分割配設され、
常時磁力により前記前記磁石支持柱に吸引固着される重
錘であり前記駆動磁石の駆動により前記支持柱の固着を
解き駆動磁石側に磁気吸引される複数対の半環状磁性板
とから構成したことを特徴とする請求項１記載のコリオ
リ流量計。2. A method for mounting a double bell, comprising: a magnet support column made of a magnetic material having one end fixed to an outer wall of the counter balance tube at right angles to an axis of the counter balance tube; and a plurality of axially divided magnet support columns. A plurality of drive magnets fixed to the support member at symmetrical positions sandwiching the magnet support post on a cross section of the magnet support post; and a plurality of drive magnets divided between the magnet support post and the plurality of drive magnets,
A plurality of pairs of semi-circular magnetic plates that are attracted and fixed to the magnet support column by magnetic force at all times, and that are fixed to the support column by driving the drive magnet and magnetically attracted to the drive magnet side. The Coriolis flowmeter according to claim 1, wherein:
壁面に固着された第１電磁石と、該第１電磁石と所定間
隔を隔て対向し支持部材に固着された第２電磁石と、前
記第１電磁石と第２電磁石との間に配設され重錘となる
複数の磁性板とからなり、前記第１電磁石と第２電磁石
とに印加する電流差に基づいて前記第１電磁石に磁気吸
引される磁性板の数を可変とする請求項１記載のコリオ
リ流量計。3. A first electromagnet fixed to an outer wall surface of a counterbalance tube, a second electromagnet opposed to the first electromagnet at a predetermined distance and fixed to a support member, and It comprises a plurality of magnetic plates disposed between the electromagnet and the second electromagnet and serving as a weight, and is magnetically attracted to the first electromagnet based on a current difference applied to the first electromagnet and the second electromagnet. 2. The Coriolis flowmeter according to claim 1, wherein the number of magnetic plates is variable.
する請求項３記載のコリオリ流量計。4. The Coriolis flowmeter according to claim 3, wherein said magnetic plate is made of magnetic powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21842693A JP2801849B2 (en) | 1993-09-02 | 1993-09-02 | Coriolis flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21842693A JP2801849B2 (en) | 1993-09-02 | 1993-09-02 | Coriolis flow meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0771989A JPH0771989A (en) | 1995-03-17 |
| JP2801849B2 true JP2801849B2 (en) | 1998-09-21 |
Family
ID=16719731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21842693A Expired - Lifetime JP2801849B2 (en) | 1993-09-02 | 1993-09-02 | Coriolis flow meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2801849B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19840782C2 (en) * | 1998-09-08 | 2001-09-06 | Krohne Messtechnik Kg | Mass flow meter |
-
1993
- 1993-09-02 JP JP21842693A patent/JP2801849B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0771989A (en) | 1995-03-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0332612B1 (en) | Ferromagnetic drive and velocity sensors for a coriolis mass flow rate meter | |
| JP4851832B2 (en) | Coriolis type mass flow meter | |
| US7143655B2 (en) | Magnetic circuit arrangement for a transducer | |
| JPH01259221A (en) | Flow rate measuring method and apparatus | |
| JPH04223224A (en) | Mass-flow-rate measuring device | |
| US5048350A (en) | Electromagnetic driver and sensor | |
| US6684716B2 (en) | Coriolis flowmeter | |
| US6439060B1 (en) | Dynamic counterbalance for Coriolis mass flowmeters | |
| JP2801849B2 (en) | Coriolis flow meter | |
| JPH05340775A (en) | Vortex flow measuring device | |
| JP2801842B2 (en) | Coriolis flow meter | |
| JPH1151733A (en) | Vibration type measuring device | |
| JP2003177048A (en) | Coriolis flowmeter | |
| JP2984134B2 (en) | Coriolis flow meter | |
| JP2004061125A (en) | Vibration type measurement device | |
| JP3767120B2 (en) | Vibration measuring device | |
| JPS61102513A (en) | Gyroscope device | |
| JP2010048751A (en) | Electrically operated vibration meter | |
| JP2004294090A (en) | Oscillating type measuring device | |
| JP3051681B2 (en) | Coriolis flow meter | |
| US20010049971A1 (en) | Coriolis flowmeter | |
| JPH109925A (en) | Coriolis flow meter | |
| JPH032543A (en) | Density and viscosity meter | |
| JPH0331725A (en) | Coriolis flow meter | |
| JP2001066103A (en) | Displacement detector applying helmholtz coil |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 11 Free format text: PAYMENT UNTIL: 20090710 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100710 Year of fee payment: 12 |