JPH0862013A - Coriolis mass flowmeter - Google Patents
Coriolis mass flowmeterInfo
- Publication number
- JPH0862013A JPH0862013A JP6200396A JP20039694A JPH0862013A JP H0862013 A JPH0862013 A JP H0862013A JP 6200396 A JP6200396 A JP 6200396A JP 20039694 A JP20039694 A JP 20039694A JP H0862013 A JPH0862013 A JP H0862013A
- Authority
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- Prior art keywords
- signal
- vibration
- coriolis
- flow rate
- mass flow
- 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.)
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- Measuring Volume Flow (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、コリオリ質量流量計に
関し、特にコリオリ力の検出方法及び信号処理回路を改
良したコリオリ質量流量計に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Coriolis mass flowmeter, and more particularly to a Coriolis mass flowmeter with improved Coriolis force detection method and signal processing circuit.
【０００２】[0002]
【従来の技術】コリオリ質量流量計とは、被測定流体が
流れるチューブを振動させ、この際に生じるコリオリ力
を検出して被測定流体の質量流量を測定する装置であ
る。2. Description of the Related Art A Coriolis mass flow meter is a device for vibrating a tube through which a fluid to be measured is vibrated and detecting the Coriolis force generated at this time to measure the mass flow rate of the fluid to be measured.
【０００３】図５はこのような従来のコリオリ質量流量
計の基本概念を示す斜視図である。図５において１はＵ
字管のチューブ、２及び３はチューブ１の固定端、４は
加振器、５及び６は振動検出器である。FIG. 5 is a perspective view showing the basic concept of such a conventional Coriolis mass flowmeter. In FIG. 5, 1 is U
The tubes 2 and 3 are fixed ends of the tube 1, 4 are vibrators, and 5 and 6 are vibration detectors.
【０００４】チューブ１は固定端２及び３の部分で固定
され、チューブ１の中心部には加振器４が設けられる。
また、加振器４と固定端２との間及び加振器４と固定端
３との間にはそれぞれ振動検出器５及び６が設けられ
る。The tube 1 is fixed at the fixed ends 2 and 3, and a vibrator 4 is provided at the center of the tube 1.
Further, vibration detectors 5 and 6 are provided between the vibrator 4 and the fixed end 2 and between the vibrator 4 and the fixed end 3, respectively.
【０００５】ここで、図５に示す従来例の動作を図６を
用いて説明する。図６はチューブ１の振動モードを説明
する斜視図である。The operation of the conventional example shown in FIG. 5 will be described with reference to FIG. FIG. 6 is a perspective view illustrating the vibration mode of the tube 1.
【０００６】チューブ１の内部に被測定流体を流し、加
振器４により図５中”イ”及び”ロ”の方向に振動を印
加した場合、図６（Ａ）に示すようにチューブ１は”Ｍ
１”〜”Ｍ３”のように振動する（曲げモード）。これ
は、チューブ１の中心部が振動の腹となる１次モード形
状で振動することを意味する。When the fluid to be measured is flown inside the tube 1 and vibration is applied by the vibration exciter 4 in the directions of "a" and "b" in FIG. 5, the tube 1 is moved as shown in FIG. 6 (A). "M
It vibrates like 1 "to" M3 "(bending mode), which means that the central part of the tube 1 vibrates in a first-order mode shape which is an antinode of vibration.
【０００７】このような振動はチューブ１の上流側及び
下流側について考えると固定端２及び３を中心とする回
転運動と見做すことができるので、この回転運動の角速
度を”ω”、被測定流体の質量流量を”Ｑ”した場
合、”ω”と”Ｑ”との積に比例したコリオリ力がチュ
ーブ１の各微小区間に生じる。Considering the upstream side and the downstream side of the tube 1, such vibration can be regarded as a rotary motion centered on the fixed ends 2 and 3, so that the angular velocity of this rotary motion is "ω", When the mass flow rate of the measurement fluid is “Q”, Coriolis force proportional to the product of “ω” and “Q” is generated in each minute section of the tube 1.
【０００８】このコリオリ力によってチューブ１は図６
（Ｂ）中”Ｍ４”〜”Ｍ６”に示すような振動をする
（ねじりモード）。この振動はチューブ１の中心部に対
して上流部と下流部とで振動方向が対象になっている。This Coriolis force causes the tube 1 to move as shown in FIG.
(B) Vibrates as shown in "M4" to "M6" in the middle (torsion mode). This vibration is intended for the vibration direction in the upstream portion and the downstream portion with respect to the central portion of the tube 1.
【０００９】従って、実際には上述の２種類の振動が重
畳された状態でチューブ１が振動することになる。振動
検出器５及び６ではこのような振動を検出し、信号処理
を行うことにより質量流量”Ｑ”を得ている。Therefore, the tube 1 actually vibrates in a state in which the above-mentioned two types of vibrations are superimposed. The vibration detectors 5 and 6 detect such vibrations and perform signal processing to obtain the mass flow rate "Q".
【００１０】コリオリ力によるチューブ１の変形に基づ
き質量流量を求める信号処理方法としては、例えば、同
期整流及び積分による処理、振動検出器５及び６の出力
の位相差を用いる処理等がある。As a signal processing method for obtaining the mass flow rate based on the deformation of the tube 1 due to the Coriolis force, there are, for example, processing by synchronous rectification and integration, processing using the phase difference between the outputs of the vibration detectors 5 and 6.
【００１１】[0011]
【発明が解決しようとする課題】しかし、被測定流体の
平均流速が１ｍ／ｓｅｃの場合でもコリオリ力によって
生じる振動振幅、即ち図６中の”Ｍ４”〜”Ｍ６”の振
動は、チューブ１に印加される振動振幅、即ち図６中
の”Ｍ１”〜”Ｍ３”と比較して、数１００分の１程度
であり、発生する位相差も０．１°程度と小さい。However, even when the average flow velocity of the fluid to be measured is 1 m / sec, the vibration amplitude generated by the Coriolis force, that is, the vibrations of "M4" to "M6" in FIG. Compared with the applied vibration amplitude, that is, “M1” to “M3” in FIG. 6, it is about several hundredths, and the generated phase difference is also small, about 0.1 °.
【００１２】この結果、コリオリ振動成分の検出が困難
であると言った問題点があった。そこで、従来では演算
増幅器等で振動検出器５及び６の出力の差信号を得るこ
とにより、加振により生じる励振成分を除去し、コリオ
リ振動成分のみを処理して質量流量を得ていた。As a result, there is a problem that it is difficult to detect the Coriolis vibration component. Therefore, conventionally, by obtaining the difference signal between the outputs of the vibration detectors 5 and 6 with an operational amplifier or the like, the excitation component generated by the vibration is removed, and only the Coriolis vibration component is processed to obtain the mass flow rate.
【００１３】但し、この方法では電気的に差信号を得た
り、電気的に信号を増幅するため、温度変動等による影
響を受けやすく高精度の測定が困難であった。従って本
発明の目的は、温度変動等による影響を受けず高精度測
定が可能なコリオリ質量流量計を実現することにある。However, since this method electrically obtains a difference signal and electrically amplifies the signal, it is easily affected by temperature fluctuations and the like, and high-precision measurement is difficult. Therefore, an object of the present invention is to realize a Coriolis mass flowmeter capable of highly accurate measurement without being affected by temperature fluctuations and the like.
【００１４】[0014]
【課題を解決するための手段】このような目的を達成す
るために、本発明の第１では、被測定流体が流れる管を
振動させ、この際に生じるコリオリ力を検出して前記被
測定流体の質量流量を測定するコリオリ質量流量計にお
いて、前記管を加振する加振器と、２種類の導線を同一
のコイルボビンに巻いて前記管の振動振幅を検出する第
１及び第２の振動検出器から構成され、この２つの振動
検出器の出力の和信号及び差信号を出力するセンサ手段
と、このセンサ手段からの前記和信号に基づき前記加振
器に駆動信号を供給すると共に、前記差信号及び前記和
信号に基づき前記質量流量を求める信号処理回路とを備
えたことを特徴とするものである。In order to achieve such an object, according to the first aspect of the present invention, a pipe through which a fluid to be measured flows is vibrated, and Coriolis force generated at this time is detected to detect the fluid to be measured. In a Coriolis mass flowmeter for measuring the mass flow rate of a pipe, a vibrator for exciting the pipe and first and second vibration detectors for winding two kinds of conductive wires around the same coil bobbin to detect the vibration amplitude of the pipe Means for outputting a sum signal and a difference signal of the outputs of the two vibration detectors, and a drive signal to the vibrator based on the sum signal from the sensor means, and the difference A signal processing circuit for determining the mass flow rate based on a signal and the sum signal.
【００１５】本発明の第２では、本発明の第１に対して
センサ手段を構成する第１及び第２の振動検出器の設置
位置若しくは第１及び第２の振動検出器の各々の巻数を
異ならせたことを特徴とするものである。In the second aspect of the present invention, the installation position of the first and second vibration detectors constituting the sensor means or the number of turns of each of the first and second vibration detectors is set to the first aspect of the present invention. The feature is that they are different.
【００１６】[0016]
【作用】２つの振動検出器の差信号及び和信号を導線の
接続方法により直接的に検出して質量流量を得ることに
より、温度変動等による影響を受けず、高精度測定が可
能になる。The difference signal and the sum signal of the two vibration detectors are directly detected by the connecting method of the lead wires to obtain the mass flow rate, and thus the high accuracy measurement can be performed without being affected by the temperature fluctuation and the like.
【００１７】また、２つの振動検出器の各出力の大きさ
を異ならせることにより、温度変動等による影響を受け
ず、高精度測定が可能になる。Further, by making the magnitudes of the outputs of the two vibration detectors different from each other, it is possible to perform highly accurate measurement without being affected by temperature fluctuations and the like.
【００１８】[0018]
【実施例】以下本発明を図面を用いて詳細に説明する。
図１は本発明に係るコリオリ質量流量計の基本概念を示
す斜視図である。ここで、１〜４は図５と同一符号を付
してある。図１において５ａ及び６ａは振動検出器であ
り、振動検出器５ａ及び６ａはセンサ手段５０を構成し
ている。但し、振動検出器５ａ及び６ａは固定端２及び
３に対して対称な位置に設置されている。The present invention will be described in detail below with reference to the drawings.
FIG. 1 is a perspective view showing the basic concept of a Coriolis mass flowmeter according to the present invention. Here, 1 to 4 are assigned the same reference numerals as those in FIG. In FIG. 1, 5a and 6a are vibration detectors, and the vibration detectors 5a and 6a constitute a sensor means 50. However, the vibration detectors 5a and 6a are installed symmetrically with respect to the fixed ends 2 and 3.
【００１９】また、接続関係についても図５とほぼ同一
である。異なる点は振動検出器５ａ及び６ａの構造であ
り、その構造は図２に示す通りである。ここで、図２は
センサ手段５０を構成する振動検出器５ａ及び６ａの導
線の接続関係を示す説明図である。The connection relationship is almost the same as in FIG. The different point is the structure of the vibration detectors 5a and 6a, and the structure is as shown in FIG. Here, FIG. 2 is an explanatory view showing the connection relationship of the conductors of the vibration detectors 5a and 6a which constitute the sensor means 50.
【００２０】すなわち、振動検出器５ａは図２中”イ”
及び”ロ”の２つの導線が同一のコイルボビン（図示せ
ず。）に巻かれた構成であり、同様に振動検出器６ａは
図２中”ハ”及び”ニ”の２つの導線が同一のコイルボ
ビン（図示せず。）に巻かれた構成となっている。That is, the vibration detector 5a is "a" in FIG.
2 and "b" are wound around the same coil bobbin (not shown). Similarly, in the vibration detector 6a, the two wires "c" and "d" are the same in FIG. It is configured to be wound around a coil bobbin (not shown).
【００２１】また、各導線の接続方法については導線”
イ”及び”ハ”はチューブ１の振動速度”Ｚ１”及び”
Ｚ２”が加算される方向で接続され、導線”ロ”及び”
ニ”はチューブ１の振動速度”Ｚ１”から振動速度”Ｚ
２”が減算される方向で接続される。すなわち、出力
端”ホ”には振動速度和”Ｚ１＋Ｚ２”が出力され、一
方、出力端”ヘ”には振動速度差”Ｚ１−Ｚ２”が出力
される。Regarding the connection method of each conductor,
"A" and "C" are the vibration speeds of tube 1, "Z1" and "
Z2 "is connected in the direction in which they are added, and the conductors" B "and"
D "is the vibration velocity" Z1 "of the tube 1 to the vibration velocity" Z "
2 "is connected in the direction of subtraction. That is, the vibration velocity sum" Z1 + Z2 "is output to the output end" e ", while the vibration velocity difference" Z1-Z2 "is output to the output end" f ". To be done.
【００２２】また、図３は本発明に係るコリオリ質量流
量計の信号処理回路の第１の実施例を示す構成ブロック
図であり、４及び５０は図１と同一符号を付してある。
図３において、７及び８は増幅器、９は同期整流／積分
演算手段、１０は駆動回路、１１は質量流量演算手段で
ある。また、１００は振動速度差信号、１０１は振動速
度和信号、１０２はコリオリ成分信号、１０３は励振信
号、１０４は駆動信号、１０５は質量流量信号である。FIG. 3 is a configuration block diagram showing a first embodiment of the signal processing circuit of the Coriolis mass flowmeter according to the present invention, and 4 and 50 are designated by the same reference numerals as in FIG.
In FIG. 3, 7 and 8 are amplifiers, 9 is a synchronous rectification / integration calculation means, 10 is a drive circuit, and 11 is a mass flow rate calculation means. Further, 100 is a vibration velocity difference signal, 101 is a vibration velocity sum signal, 102 is a Coriolis component signal, 103 is an excitation signal, 104 is a drive signal, and 105 is a mass flow rate signal.
【００２３】センサ手段５０からの振動速度差信号１０
０及び振動速度和信号１０１は増幅器７及び８にそれぞ
れ接続され、増幅器７の出力は同期整流／積分演算手段
９に接続される。また、増幅器８の出力である励振信号
１０３は同期整流／積分演算手段９、駆動回路１０及び
質量流量演算手段１１にそれぞれ接続される。Vibration velocity difference signal 10 from the sensor means 50
0 and the vibration velocity sum signal 101 are connected to the amplifiers 7 and 8, respectively, and the output of the amplifier 7 is connected to the synchronous rectification / integration calculation means 9. The excitation signal 103, which is the output of the amplifier 8, is connected to the synchronous rectification / integration calculation means 9, the drive circuit 10, and the mass flow rate calculation means 11, respectively.
【００２４】同期整流／積分演算手段９の出力であるコ
リオリ成分信号１０２は質量流量演算手段１１に接続さ
れ、質量流量演算手段１１は質量流量信号１０５を出力
する。一方、駆動回路１０の出力は駆動信号１０４とし
て加振器４に接続される。The Coriolis component signal 102 which is the output of the synchronous rectification / integration calculation means 9 is connected to the mass flow rate calculation means 11, and the mass flow rate calculation means 11 outputs the mass flow rate signal 105. On the other hand, the output of the drive circuit 10 is connected to the vibrator 4 as the drive signal 104.
【００２５】ここで、図３に示す信号処理回路の動作を
説明する。図１及び図２に示すチューブ１の振動速度
を”Ｚ１”及び”Ｚ２”を、 Ｚ１＝Ａsinθ＋Ｃcosθ (1) Ｚ２＝Ａ’sinθ＋Ｃ’cosθ (2) とする。但し、”Ａ”及び”Ａ’”は加振器４により生
じる励振振幅成分であり、”Ｃ”及び”Ｃ’”はコリオ
リ力によって生じるコリオリ振幅成分である。The operation of the signal processing circuit shown in FIG. 3 will be described. The vibration speeds of the tube 1 shown in FIGS. 1 and 2 are “Z1” and “Z2”, and Z1 = A sin θ + C cos θ (1) Z2 = A ′ sin θ + C ′ cos θ (2). However, "A" and "A '" are excitation amplitude components generated by the vibrator 4, and "C" and "C'" are Coriolis amplitude components generated by the Coriolis force.
【００２６】図２のような導線の接続をとることによっ
て、センサ手段５０からはチューブ１の振動速度の差信
号と和信号が得られ、式（１）及び（２）から、 Ｚ１−Ｚ２＝(Ａ−Ａ’)sinθ＋(Ｃ＋Ｃ’)cosθ (3) Ｚ１＋Ｚ２＝(Ａ＋Ａ’)sinθ＋(Ｃ−Ｃ’)cosθ (4) となる。By connecting the conductors as shown in FIG. 2, the difference signal and the sum signal of the vibration velocity of the tube 1 are obtained from the sensor means 50, and from the equations (1) and (2), Z1-Z2 = (A−A ′) sin θ + (C + C ′) cos θ (3) Z1 + Z2 = (A + A ′) sin θ + (CC ′) cos θ (4)
【００２７】式（４）においてコリオリ振幅成分は励振
振幅成分よりも遙に小さいので、 Ｚ１＋Ｚ２≒(Ａ＋Ａ’)sinθ (5) と近似でき、振動速度和信号１０１からは励振振幅成分
のみの検出が可能になる。Since the Coriolis amplitude component is much smaller than the excitation amplitude component in the equation (4), it can be approximated as Z1 + Z2≈ (A + A ') sin θ (5), and only the excitation amplitude component can be detected from the vibration velocity sum signal 101. It will be possible.
【００２８】この振動速度和信号１０１は増幅器８を介
して励振信号１０３となり、駆動回路１０は励振信号１
０３を用いて駆動信号１０４を発生させ、また、励振信
号１０３は同期整流／積分演算手段９及び質量流量演算
手段１１に対して基準信号等として供給される。This vibration velocity sum signal 101 becomes an excitation signal 103 via the amplifier 8, and the drive circuit 10 makes the excitation signal 1
03 is used to generate the drive signal 104, and the excitation signal 103 is supplied to the synchronous rectification / integration calculation means 9 and the mass flow rate calculation means 11 as a reference signal or the like.
【００２９】一方、理想的には”Ａ＝Ａ’”であり、式
（３）から振動速度差信号１００はコリオリ振幅成分の
みになるはずであるが、実際には”Ａ≠Ａ’”であり、
振動速度差信号１００はコリオリ振幅成分と励振振幅成
分が混在した信号になる。On the other hand, ideally "A = A '", and the vibration velocity difference signal 100 should be only the Coriolis amplitude component from the equation (3), but in reality "A ≠ A'". Yes,
The vibration velocity difference signal 100 is a signal in which the Coriolis amplitude component and the excitation amplitude component are mixed.
【００３０】従って、同期整流／積分演算手段９で振動
速度和信号１０１を基準信号として振動速度差信号１０
０の同期整流及び積分を行うことにより、振動速度差信
号１００は、 ∫(Ｚ１−Ｚ２)dθ＝∫{(Ａ−Ａ’)sinθ＋(Ｃ＋Ｃ’)cosθ}dθ ＝Ｃ＋Ｃ’ (6) 但し、”∫”は”π／２＋２ｎπ”〜”３π／２＋２ｎ
π”の区間を積分することを意味する。となる。Therefore, the synchronous rectification / integration calculation means 9 uses the vibration velocity sum signal 101 as a reference signal and the vibration velocity difference signal 10
By performing synchronous rectification and integration of 0, the vibration speed difference signal 100 is ∫ (Z1-Z2) dθ = ∫ {(A−A ′) sinθ + (C + C ′) cosθ} dθ = C + C ′ (6) "∫" is "π / 2 + 2nπ" to "3π / 2 + 2n"
It means to integrate the interval of π ″.
【００３１】式（６）よりコリオリ振幅成分”Ｃ＋
Ｃ’”のみが得られ、コリオリ成分信号１０２として同
期整流／積分演算手段９から出力される。コリオリ成分
信号１０２は質量流量に比例するので、コリオリ成分信
号１０２を用いて質量流量を得ることができる。From the equation (6), the Coriolis amplitude component "C +"
Only C ′ ″ is obtained and output as the Coriolis component signal 102 from the synchronous rectification / integration calculation means 9. Since the Coriolis component signal 102 is proportional to the mass flow rate, the Coriolis component signal 102 can be used to obtain the mass flow rate. it can.
【００３２】但し、コリオリ成分信号１０２は励振振
幅、励振周波数及び温度等による補正が必要なので質量
流量演算手段１１において当該補正がなされ質量流量信
号１０５として出力される。However, since the Coriolis component signal 102 needs to be corrected by the excitation amplitude, the excitation frequency, the temperature, etc., the Coriolis component signal 102 is corrected by the mass flow rate calculation means 11 and output as the mass flow rate signal 105.
【００３３】この結果、２つの振動検出器の差信号及び
和信号を導線の接続方法により直接的に検出することに
より、電気的に差信号及び和信号を得たりする必要がな
いので、従来例と比較して温度変動等による影響を受け
ず、また、差信号を直接的に検出することにより差信号
のコリオリ振幅成分の混入率が高くなり高精度測定が可
能になる。As a result, since it is not necessary to electrically obtain the difference signal and the sum signal by directly detecting the difference signal and the sum signal of the two vibration detectors by the method of connecting the conductors, the conventional example. Compared with the above, it is not affected by temperature fluctuation and the like, and by directly detecting the difference signal, the mixing rate of the Coriolis amplitude component of the difference signal is increased, and highly accurate measurement becomes possible.
【００３４】但し、式（３）は、 Ｚ１−Ｚ２＝{(Ａ−Ａ’)2＋(Ｃ＋Ｃ’)2}1/2 ×sin(θ＋φ) (7) 但し、φ＝tan-1{(Ｃ＋Ｃ’)／(Ａ−Ａ’)}である。と
変形でき、センサ手段５０やチューブ１の構造の微小な
非対称性により、コリオリ振幅成分と励振振幅成分との
比のバラツキが大きく製造時の調整が容易ではない。[0034] However, Equation (3) is, Z1-Z2 = {(A -A ') 2 + (C + C') 2} 1/2 × sin (θ + φ) (7) where, φ = tan -1 {( C + C ') / (AA')}. Due to the minute asymmetry of the structure of the sensor means 50 and the tube 1, the ratio of the Coriolis amplitude component to the excitation amplitude component varies greatly and adjustment during manufacture is not easy.
【００３５】さらに、”tanφ＝{(Ｃ＋Ｃ’)／(Ａ−
Ａ’)}＞１”の領域ではわずかな位相変化で”tanφ ”
が非線形的に変化する。この”tanφ ”が質量流量に比
例することから、位相差測定による質量流量の高精度測
定も困難である。Furthermore, "tan φ = {(C + C ') / (A-
A ')}> 1 ”, the small phase change causes" tanφ "
Changes non-linearly. Since this "tanφ" is proportional to the mass flow rate, it is also difficult to measure the mass flow rate with high accuracy by phase difference measurement.
【００３６】図４はこのような問題点を改善した本発明
に係るコリオリ質量流量計の信号処理回路の第２の実施
例を示す構成ブロック図であり、４，７，８，１０，１
０３及び１０４は図３と同一符号を付してある。図４に
おいて、１２は位相差検出による質量流量演算手段、１
００ａは振動速度差信号、１０１ａは振動速度和信号、
１０６は出力信号、１０７は質量流量信号である。FIG. 4 is a constitutional block diagram showing a second embodiment of the signal processing circuit of the Coriolis mass flowmeter according to the present invention, in which the above problems are improved, and is 4, 7, 8, 10, 1.
Reference numerals 03 and 104 are the same as those in FIG. In FIG. 4, reference numeral 12 is a mass flow rate calculation means by phase difference detection, 1
00a is a vibration velocity difference signal, 101a is a vibration velocity sum signal,
106 is an output signal and 107 is a mass flow rate signal.
【００３７】また、５０ａは図２に示すようなセンサ手
段であり、基本的には図３に示すセンサ手段５０と同様
であるが、図２中の導線”イ”及び”ロ”の巻数と導
線”ハ”及び”ニ”の巻数とが異なっている。Further, 50a is a sensor means as shown in FIG. 2, which is basically the same as the sensor means 50 shown in FIG. 3, except that the number of turns of the conducting wires "a" and "b" in FIG. The number of turns of the conductors "c" and "d" is different.
【００３８】センサ手段５０ａからの振動速度差信号１
００ａ及び振動速度和信号１０１ａは増幅器７及び８に
それぞれ接続され、増幅器７の出力信号１０６は質量流
量演算手段１２に接続される。また、増幅器８の出力で
ある励振信号１０３は駆動回路１０及び質量流量演算手
段１２にそれぞれ接続される。Vibration velocity difference signal 1 from the sensor means 50a
00a and the vibration velocity sum signal 101a are connected to the amplifiers 7 and 8, respectively, and the output signal 106 of the amplifier 7 is connected to the mass flow rate calculation means 12. The excitation signal 103, which is the output of the amplifier 8, is connected to the drive circuit 10 and the mass flow rate calculation means 12, respectively.
【００３９】質量流量演算手段１２は質量流量信号１０
７を出力し、駆動回路１０の出力は駆動信号１０４とし
て加振器４に接続される。The mass flow rate calculation means 12 uses the mass flow rate signal 10
7 is output, and the output of the drive circuit 10 is connected to the shaker 4 as the drive signal 104.
【００４０】ここで、図４に示す信号処理回路の動作を
説明する。センサ手段５０ａを構成する導線”イ”及
び”ロ”の巻数は”ｎ１”、導線”ハ”及び”ニ”の巻
数は”ｎ２”であり、 ｎ１＞ｎ２ (8) ｎ１＝ｒ・ｎ２ (9) という関係にある。The operation of the signal processing circuit shown in FIG. 4 will be described. The number of turns of the conducting wires "a" and "b" constituting the sensor means 50a is "n1", the number of turns of the conducting wires "c" and "d" is "n2", and n1> n2 (8) n1 = r.n2 ( 9).
【００４１】図１及び図２に示すチューブ１の振動速
度”Ｚ１”及び”Ｚ２”は前述の式（１）及び（２）で
あり、図２のような導線の接続をとることによって、セ
ンサ手段５０ａからはチューブ１の振動速度の差信号と
和信号が得られる。但し、前述の説明の式との区別を図
るため振動速度は”ｚ１”及び”ｚ２”と小文字で記載
する。The vibration velocities "Z1" and "Z2" of the tube 1 shown in FIGS. 1 and 2 are expressed by the above-mentioned formulas (1) and (2), and by connecting the lead wires as shown in FIG. From the means 50a, a difference signal of the vibration velocity of the tube 1 and a sum signal are obtained. However, in order to distinguish it from the equation described above, the vibration speed is described as a small letter such as "z1" and "z2".
【００４２】式（１）及び（２）を用いて、振動速度差
信号１００ａ及び振動速度和信号１０１ａは、 ｚ１−ｚ２＝(Ａ−ｒＡ)sinθ＋(Ｃ＋ｒＣ)cosθ ＝{(Ａ−ｒＡ)2＋(Ｃ＋ｒＣ)2}1/2 ×sin(θ＋φ) (10) 但し、φ＝tan-1{(１＋ｒ)・Ｃ／(１−ｒ)・Ａ}である。 ｚ１＋ｚ２＝(Ａ＋ｒＡ)sinθ＋(Ｃ−ｒＣ)cosθ (11) となる。Using the equations (1) and (2), the vibration velocity difference signal 100a and the vibration velocity sum signal 101a are calculated as follows: z1-z2 = (A-rA) sinθ + (C + rC) cosθ = {(A-rA) 2 + (C + rC) 2 } 1/2 × sin (θ + φ) (10) where φ = tan −1 {(1 + r) · C / (1-r) · A}. z1 + z2 = (A + rA) sin θ + (C−rC) cos θ (11).
【００４３】式（１１）においてコリオリ振幅成分は励
振振幅成分よりも遙に小さいので、 ｚ１＋ｚ２≒(Ａ＋ｒＡ)sinθ (12) と近似でき、振動速度和信号１０１ａからは励振振幅成
分のみの検出が可能になる。Since the Coriolis amplitude component is much smaller than the excitation amplitude component in equation (11), it can be approximated as z1 + z2≈ (A + rA) sin θ (12), and only the excitation amplitude component can be detected from the vibration velocity sum signal 101a. become.
【００４４】この振動速度和信号１０１ａは増幅器８を
介して出力信号１０３となり、駆動回路１０は出力信号
１０３により駆動信号１０４を発生させ、また、出力信
号１０３は質量流量演算手段１２に供給される。This vibration velocity sum signal 101a becomes an output signal 103 via the amplifier 8, the drive circuit 10 generates a drive signal 104 by the output signal 103, and the output signal 103 is supplied to the mass flow rate calculating means 12. .
【００４５】一方、振動速度差信号１００ａはコリオリ
振幅成分と励振振幅成分が混在した信号であり、質量流
量演算手段１２は振動速度差信号１００ａの位相と振動
速度和信号１０１ａの位相の差に基づき質量流量を求め
る。On the other hand, the vibration velocity difference signal 100a is a signal in which the Coriolis amplitude component and the excitation amplitude component are mixed, and the mass flow rate calculation means 12 is based on the difference between the phase of the vibration velocity difference signal 100a and the phase of the vibration velocity sum signal 101a. Calculate the mass flow rate.
【００４６】式（１０）の”φ”に関し、 tanφ＝ｒ'・Ｃ／Ａ (13) 但し、ｒ'＝(１＋ｒ)／(１−ｒ)である。であり、”Ｃ
／Ａ”は質量流量に比例することから、”tanφ ”は質
量流量に比例するので、質量流量演算手段１２は位相を
検出して、この検出位相に基づき質量流量を得ている。Regarding “φ” in the equation (10), tan φ = r ′ · C / A (13) where r ′ = (1 + r) / (1-r). And then "C
Since / A ”is proportional to the mass flow rate,“ tanφ ”is proportional to the mass flow rate, and therefore the mass flow rate calculation means 12 detects the phase and obtains the mass flow rate based on this detected phase.
【００４７】この結果、２つの振動検出器５ａ及び６ａ
の各出力の大きさを異ならせてその差信号及び和信号を
得ることにより、電気的に差信号及び和信号を得たりす
る必要がないので、従来例と比較して温度変動等による
影響を受けず、また、差信号を直接的に検出することに
より差信号のコリオリ振幅成分の混入率が高くなり高精
度測定が可能になる。As a result, the two vibration detectors 5a and 6a
Since it is not necessary to electrically obtain the difference signal and the sum signal by changing the magnitude of each output of the above to obtain the difference signal and the sum signal, it is possible to reduce the influence of temperature fluctuation and the like as compared with the conventional example. By not directly receiving the difference signal and directly detecting the difference signal, the mixing rate of the Coriolis amplitude component of the difference signal becomes high, and high-precision measurement becomes possible.
【００４８】特に、導線”イ”〜”ニ”の巻数を異なら
せて２つの振動検出器５ａ及び６ａの各出力の大きさを
異ならせることによって、式（１０）の但書に示すよう
に位相差に対し巻数比に関連する係数が乗じられること
になり、この係数”ｒ”を適当に調節することにより、 ０．１＜tanφ＜１．０ (14) にすることができる。In particular, by varying the number of turns of the conductors "a" to "d" to vary the magnitudes of the outputs of the two vibration detectors 5a and 6a, as shown in the proviso of equation (10). The phase difference is multiplied by a coefficient related to the turns ratio, and by appropriately adjusting this coefficient "r", 0.1 <tanφ <1.0 (14) can be obtained.
【００４９】即ち、式（１４）に示す範囲内では位相
差”φ”と質量流量に比例する”tanφ ”とが比較的線
形的に対応するので精度の良い測定が可能になる。That is, within the range shown in the equation (14), the phase difference "φ" and "tanφ" proportional to the mass flow rate relatively linearly correspond to each other, so that accurate measurement can be performed.
【００５０】さらに、式（１４）に示す範囲内ではセン
サ手段５０やチューブ１の構造の微小な非対称性でコリ
オリ振幅成分と励振振幅成分との比にある程度のバラツ
キがあっても、”tanφ ”は”(１＋ｒ)／(１−ｒ)”で
支配的に決まるため”tanφ”のフルスケールの値のバ
ラツキは少なくなり製造時の調整も容易になる。Further, within the range shown in the equation (14), even if there is some variation in the ratio between the Coriolis amplitude component and the excitation amplitude component due to the minute asymmetry of the structure of the sensor means 50 and the tube 1, "tanφ". Is dominantly determined by “(1 + r) / (1-r)”, the variation in the full scale value of “tan φ” is reduced and the adjustment at the time of manufacturing becomes easy.
【００５１】また、導線”イ”〜”ニ”の巻数を異なら
せる代わりに振動検出器５ａ及び６ａを固定端２及び３
に対して非対称な位置に設置することにより、同様の効
果、即ち、チューブ１の構造の微小な非対称性によるコ
リオリ振幅成分と励振振幅成分との比の変動を小さくす
ることができる。Further, the vibration detectors 5a and 6a are fixed to the fixed ends 2 and 3 instead of changing the number of turns of the conductive wires "a" to "d".
The same effect, that is, the variation in the ratio between the Coriolis amplitude component and the excitation amplitude component due to the minute asymmetry of the structure of the tube 1 can be reduced by installing the asymmetrical position with respect to the above.
【００５２】なお、図１及び図３に示すセンサ手段５０
若しくは図４に示すセンサ手段５０ａの実施例では加振
器４でチューブ１を”曲げモード”で加振することによ
り、”ねじりモード”のコリオリ振動を発生させている
が、逆の場合も可能である。即ち、２つの加振器を用い
チューブ１を”ねじりモード”で加振することによ
り、”曲げモード”のコリオリ振動を発生させることも
可能である。The sensor means 50 shown in FIGS. 1 and 3 is used.
Alternatively, in the embodiment of the sensor means 50a shown in FIG. 4, by vibrating the tube 1 in the "bending mode" by the vibration exciter 4, Coriolis vibrations in the "torsion mode" are generated, but the reverse case is also possible. Is. That is, it is possible to generate Coriolis vibration in the "bending mode" by vibrating the tube 1 in the "twisting mode" using two vibrators.
【００５３】また、実施例ではチューブ１として１本の
Ｕ字管を用いた場合を示したが、振動するチューブの構
造はこれに限るわけではない。例えば、直管構造等でも
良く、また、２本の平行管等の複数本の管を用いる構造
であっても良い。Further, in the embodiment, the case where one U-shaped tube is used as the tube 1 is shown, but the structure of the vibrating tube is not limited to this. For example, a straight pipe structure or the like may be used, or a structure using a plurality of pipes such as two parallel pipes may be used.
【００５４】また、センサ手段５０ａの２つの出力信号
を図３に示す信号処理回路で処理することにより、質量
流量を得ることも可能である。It is also possible to obtain the mass flow rate by processing the two output signals of the sensor means 50a by the signal processing circuit shown in FIG.
【００５５】また、前述の説明ではセンサ手段５０ａを
構成する導線”イ”及び”ロ”の巻数は”ｎ１”、導
線”ハ”及び”ニ”の巻数は”ｎ２”としたが、導線”
イ”，”ロ”，”ハ”及び”ニ”の巻数を”ｎａ”，”
ｎｂ”，”ｎｃ”及び”ｎｄ”と互いに異なる巻数にし
ても良い。In the above description, the number of turns of the conducting wires "a" and "b" constituting the sensor means 50a is "n1" and the number of turns of the conducting wires "c" and "d" is "n2".
The number of turns of "a", "b", "c" and "d" is "na", "
The number of turns may be different from nb "," nc ", and" nd ".
【００５６】すなわち、前記各巻数の相互関係を、 ｎｂ＝ｒ・ｎａ ｎｄ＝ｒ・ｎｃ ｎａ＝ｓ・ｎｃ ｎｂ＝ｓ・ｎｄ (15) 但し、０＜ｒ＜１、０＜ｓ＜１である。とする。That is, the mutual relation of the numbers of turns is expressed as follows: nb = r.na nd = r.nc na = s.nc nb = s.nd (15) where 0 <r <1 and 0 <s <1 is there. And
【００５７】この場合、振動速度差信号及び振動速度和
信号は、 ｚ１'−ｚ２'＝(Ａ−ｒＡ)sinθ＋(Ｃ−ｒＣ)cosθ ＝{(Ａ−ｒＡ)2＋(Ｃ＋ｒＣ)2}1/2 ×sin(θ＋φ) (16) ｚ１'＋ｚ２'＝ｓ・(Ａ＋ｒＡ)sinθ＋ｓ・(Ｃ−ｒＣ)cosθ ≒ｓ・(Ａ＋ｒＡ)sinθ (17) となる。[0057] In this case, the vibration speed difference signal and an oscillation speed sum signal, z1'-z2 '= (A -rA) sinθ + (C-rC) cosθ = {(A-rA) 2 + (C + rC) 2} 1 / 2 × sin (θ + φ) (16) z1 ′ + z2 ′ = s · (A + rA) sinθ + s · (C−rC) cosθ ≈s · (A + rA) sinθ (17).
【００５８】式（１４）及び（１５）から振動速度差信
号及び振動速度和信号の振幅がほぼ同じになようよう
に”ｓ”を設定することにより、初段増幅器である増幅
器７及び８は同じ利得の増幅器を用いることが可能にな
る。From equations (14) and (15), by setting "s" so that the amplitudes of the vibration velocity difference signal and the vibration velocity sum signal are almost the same, the amplifiers 7 and 8 which are the first stage amplifiers are the same. It becomes possible to use a gain amplifier.
【００５９】この結果、初段増幅器の利得の違いによる
温度の影響等を抑えることが可能になり、より高精度測
定が可能になる。As a result, it is possible to suppress the influence of temperature and the like due to the difference in gain of the first-stage amplifier, and it becomes possible to perform more accurate measurement.
【００６０】[0060]
【発明の効果】以上説明したことから明らかなように、
本発明によれば次のような効果がある。請求項１の発明
に関しては、２つの振動検出器の差信号及び和信号を導
線の接続方法により直接的に検出して質量流量を得るこ
とにより、温度変動等による影響を受けず、高精度測定
が可能なコリオリ質量流量計が実現できる。As is apparent from the above description,
The present invention has the following effects. According to the first aspect of the invention, the difference signal and the sum signal of the two vibration detectors are directly detected by the method of connecting the conductors to obtain the mass flow rate, so that it is not affected by temperature fluctuations and the like and highly accurate measurement is performed. It is possible to realize a Coriolis mass flowmeter capable of
【００６１】また、請求項２の発明に関しては、センサ
手段を構成する２つの振動検出器の設置位置若しくは２
つの振動検出器の各々の巻数を異ならせて、２つの振動
検出器の各出力の大きさを異ならせることにより、温度
変動等による影響を受けず、高精度測定が可能で、且
つ、質量流量のフルスケール時のセンサ手段のバラツキ
が小さくなり製造時の調整が容易なコリオリ質量流量計
が実現できる。Further, according to the invention of claim 2, the installation positions of the two vibration detectors constituting the sensor means or the two vibration detectors are set.
By changing the number of turns of each of the two vibration detectors and the size of each output of the two vibration detectors, high-precision measurement is possible without being affected by temperature fluctuations, etc. The variation of the sensor means at full scale can be reduced, and a Coriolis mass flowmeter that can be easily adjusted during manufacturing can be realized.
【図１】本発明に係るコリオリ質量流量計の基本概念を
示す斜視図である。FIG. 1 is a perspective view showing the basic concept of a Coriolis mass flowmeter according to the present invention.
【図２】振動検出器の導線の接続関係を示す説明図であ
る。FIG. 2 is an explanatory diagram showing a connection relationship of conductors of a vibration detector.
【図３】本発明に係るコリオリ質量流量計の信号処理回
路の第１の実施例を示す構成ブロック図である。FIG. 3 is a configuration block diagram showing a first embodiment of the signal processing circuit of the Coriolis mass flowmeter according to the present invention.
【図４】本発明に係るコリオリ質量流量計の信号処理回
路の第２の実施例を示す構成ブロック図である。FIG. 4 is a configuration block diagram showing a second embodiment of the signal processing circuit of the Coriolis mass flowmeter according to the present invention.
【図５】従来のコリオリ質量流量計の基本概念を示す斜
視図である。FIG. 5 is a perspective view showing the basic concept of a conventional Coriolis mass flowmeter.
【図６】チューブの振動モードを説明する斜視図であ
る。FIG. 6 is a perspective view illustrating a vibration mode of a tube.
１ チューブ ２，３ 固定端 ４ 加振器 ５，５ａ，６，６ａ 振動検出器 ７，８ 増幅器 ９ 同期整流／積分演算手段 １０ 駆動回路 １１，１２ 質量流量演算手段 ５０，５０ａ センサ手段 １００，１００ａ 振動速度差信号 １０１，１０１ａ 振動速度和信号 １０２ コリオリ成分信号 １０３ 励振信号 １０４ 駆動信号 １０５，１０７ 質量流量信号 １０６ 出力信号 DESCRIPTION OF SYMBOLS 1 tube 2,3 fixed end 4 vibrator 5,5a, 6,6a vibration detector 7,8 amplifier 9 synchronous rectification / integral calculation means 10 drive circuit 11,12 mass flow rate calculation means 50,50a sensor means 100,100a Vibration velocity difference signal 101, 101a Vibration velocity sum signal 102 Coriolis component signal 103 Excitation signal 104 Drive signal 105, 107 Mass flow rate signal 106 Output signal
Claims (2)
に生じるコリオリ力を検出して前記被測定流体の質量流
量を測定するコリオリ質量流量計において、 前記管を加振する加振器と、 ２種類の導線を同一のコイルボビンに巻いて前記管の振
動振幅を検出する第１及び第２の振動検出器から構成さ
れ、この２つの振動検出器の出力の和信号及び差信号を
出力するセンサ手段と、 このセンサ手段からの前記和信号に基づき前記加振器に
駆動信号を供給すると共に、前記差信号及び前記和信号
に基づき前記質量流量を求める信号処理回路とを備えた
ことを特徴とするコリオリ質量流量計。1. A Coriolis mass flowmeter for vibrating a pipe through which a fluid to be measured flows, and detecting the Coriolis force generated at this time to measure the mass flow rate of the fluid to be measured. And a first vibration detector and a second vibration detector that detect the vibration amplitude of the pipe by winding two kinds of conductors on the same coil bobbin, and output a sum signal and a difference signal of the outputs of the two vibration detectors. And a signal processing circuit that supplies a drive signal to the vibrator based on the sum signal from the sensor means and that determines the mass flow rate based on the difference signal and the sum signal. Characteristic Coriolis mass flowmeter.
検出器の設置位置若しくは第１及び第２の振動検出器の
各々の巻数を異ならせたことを特徴とする特許請求の範
囲第１項記載のコリオリ質量流量計。2. The position where the first and second vibration detectors constituting the sensor means are installed or the number of turns of each of the first and second vibration detectors is made different. The Coriolis mass flowmeter according to item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6200396A JPH0862013A (en) | 1994-08-25 | 1994-08-25 | Coriolis mass flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6200396A JPH0862013A (en) | 1994-08-25 | 1994-08-25 | Coriolis mass flowmeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0862013A true JPH0862013A (en) | 1996-03-08 |
Family
ID=16423631
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6200396A Pending JPH0862013A (en) | 1994-08-25 | 1994-08-25 | Coriolis mass flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0862013A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009069144A (en) * | 2007-09-10 | 2009-04-02 | Berkin Bv | Device and method for measuring coriolis-type mass flow having at least three sensor measuring sections |
-
1994
- 1994-08-25 JP JP6200396A patent/JPH0862013A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009069144A (en) * | 2007-09-10 | 2009-04-02 | Berkin Bv | Device and method for measuring coriolis-type mass flow having at least three sensor measuring sections |
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