JP2841199B2 - Mass flow meter - Google Patents
Mass flow meterInfo
- Publication number
- JP2841199B2 JP2841199B2 JP63142264A JP14226488A JP2841199B2 JP 2841199 B2 JP2841199 B2 JP 2841199B2 JP 63142264 A JP63142264 A JP 63142264A JP 14226488 A JP14226488 A JP 14226488A JP 2841199 B2 JP2841199 B2 JP 2841199B2
- Authority
- JP
- Japan
- Prior art keywords
- resistors
- circuit
- output
- constant temperature
- temperature control
- 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
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、流体が流れる導管に２つの抵抗体を互いに
独立して巻設したマスフローメータの改良に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a mass flow meter in which two resistors are independently wound around a conduit through which a fluid flows.
上記マスフローメータにおいては、流体が流れる導管
に２つの抵抗体を互いに独立して巻設し、これら両抵抗
体の温度を一定に保持するため、両抵抗体にそれぞれ電
流を供給し、そのときの両抵抗体に供給される電力の差
に基づいて、導管内を流れる流体の質量流量を検出する
ようにしている。In the above mass flow meter, two resistors are independently wound around a conduit through which a fluid flows, and a current is supplied to each of the resistors in order to keep the temperature of the resistors constant. The mass flow rate of the fluid flowing through the conduit is detected based on the difference between the powers supplied to the two resistors.
しかしながら、従来においては、前記抵抗体に流す電
流の方向が明確に規定されていなかったため、抵抗体間
の相互電磁誘導作用によりノイズレベルの高い出力信
号、つまり、S/N比がよくない出力信号しか得られなか
った。マスフローメータとして実用上問題がないレベル
までノイズを低減するには、信号処理部にノイズフィル
タを設ければよいが、このようにすると応答性が損なわ
れてしまい、高精度かつ高速応答性を有するマスフロー
メータを得る上での大きな障害となっていた。However, conventionally, since the direction of the current flowing through the resistor has not been clearly defined, an output signal having a high noise level due to the mutual electromagnetic induction between the resistors, that is, an output signal having a poor S / N ratio. I could only get it. In order to reduce noise to a level that does not cause a practical problem as a mass flow meter, a noise filter may be provided in the signal processing unit. However, in this case, responsiveness is impaired, and high accuracy and high speed responsiveness are obtained. This was a major obstacle to obtaining a mass flow meter.
本発明は、上述の事柄に留意してなされたもので、そ
の目的とするところは、ノイズ影響の少ない出力信号を
高速応答で精度よく得ることができるマスフローメータ
を提供することにある。SUMMARY OF THE INVENTION The present invention has been made in consideration of the above, and an object of the present invention is to provide a mass flow meter that can obtain an output signal with little influence of noise with high speed response and high accuracy.
上述の目的を達成するため、本発明に係るマスフロー
メータは、流体が流れる導管に温度感応抵抗線によりな
る２つの抵抗体を互いに独立させて間隔をおいて巻設し
たマスフローメータにおいて、前記２つの抵抗体にそれ
ぞれ生ずる磁界の向きが前記流体の流れる方向と逆向き
になるように、かつ、前記両抵抗体の温度が常に所定の
温度で相等しくなるように、前記各抵抗体にそれぞれ制
御電流を供給する２つの定温度制御回路を設けると共
に、その両定温度制御回路からの出力電位を加算する加
算回路と、一方の前記定温度制御回路の出力電位から他
方の前記定温度制御回路の出力電位を減算する減算回路
と、前記減算回路からの減算出力を前記加算回路からの
加算出力で除算する除算回路とを設けてなることを特徴
としている。In order to achieve the above object, a mass flow meter according to the present invention is a mass flow meter in which two resistors made of a temperature-sensitive resistance wire are wound around a conduit through which a fluid flows independently of each other at an interval. A control current is applied to each of the resistors so that the directions of the magnetic fields generated in the resistors are opposite to the direction in which the fluid flows, and the temperatures of the resistors are always equal at a predetermined temperature. A constant temperature control circuit for supplying the constant temperature control circuit, and an addition circuit for adding the output potentials of the two constant temperature control circuits, and an output of the other constant temperature control circuit from the output potential of one of the constant temperature control circuits. A subtraction circuit for subtracting a potential and a division circuit for dividing a subtraction output from the subtraction circuit by an addition output from the addition circuit are provided.
上記構成によれば、流体が流れる導管に巻設された２
つの抵抗体にそれぞれ生ずる磁界の向きが前記流体の方
向と逆になるように、両定温度制御回路から各抵抗体に
制御電流を流すようにすると共に、加算回路、減算回路
および除算回路を設け、両定温度制御回路からの減算出
力を加算出力で除算して除算出力を得るようにしたの
で、ノイズフィルタを用いなくてもノイズの影響がない
出力信号を高速応答で精度よく得ることができる。According to the above configuration, 2 is wound around the conduit through which the fluid flows.
A control current is passed from the constant temperature control circuits to the respective resistors so that the directions of the magnetic fields generated in the three resistors are opposite to the directions of the fluids, and an addition circuit, a subtraction circuit, and a division circuit are provided. Since the subtraction output from both constant temperature control circuits is divided by the addition output to obtain a division calculation power, an output signal free from the influence of noise without using a noise filter can be accurately obtained with high speed response. .
以下、本発明の一実施例を、図面を参照しながら説明
する。Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
第１図は本発明に係るマスフローメータの一構成例を
示し、同図において、１は流体Ｆが流れる導管で、矢印
方向に流体Ｆが流れる。FIG. 1 shows an example of the configuration of a mass flow meter according to the present invention. In FIG. 1, reference numeral 1 denotes a conduit through which a fluid F flows.
2u,2dは導管１の外周に適宜の間隔をおいて互いに逆
方向にしかも互いに独立した状態に巻設された抵抗体と
しての２つの自己加熱形感熱コイル（以下、第１抵抗体
2u,第２抵抗体2dという）である。これら第１抵抗体2u,
第２抵抗体2dは、例えば鉄・ニッケル合金等温度係数の
大なる温度感応抵抗線よりなり、導管１内を流れる流体
Ｆの流量の僅かな変化をも検知するべく構成してある。Reference numerals 2u and 2d denote two self-heating type heat-sensitive coils (hereinafter referred to as first resistor elements) as resistors wound around the outer circumference of the conduit 1 at appropriate intervals in opposite directions and independently of each other.
2u, the second resistor 2d). These first resistors 2u,
The second resistor 2d is made of, for example, a temperature-sensitive resistance wire having a large temperature coefficient such as an iron-nickel alloy, and is configured to detect a slight change in the flow rate of the fluid F flowing through the conduit 1.
3,4は第１抵抗体2u,第２抵抗体2dをそれぞれ後述する
ブリッジ回路8,14の構成要素として含む定温度制御回路
（以下、第１定温度制御回路３、第２定温度制御回路４
という）で、これら第１定温度制御回路３、第２定温度
制御回路４は互いに同一の部品より構成されており、第
１抵抗体2uと第２抵抗体2dとの温度が常に所定の温度で
相等しくなるように制御するものである。Reference numerals 3 and 4 denote constant temperature control circuits (hereinafter, referred to as a first constant temperature control circuit 3 and a second constant temperature control circuit, respectively) including the first resistor 2u and the second resistor 2d as constituent elements of bridge circuits 8 and 14 to be described later. 4
The first constant temperature control circuit 3 and the second constant temperature control circuit 4 are composed of the same components, and the first resistor 2u and the second resistor 2d always have a predetermined temperature. Are controlled to be equal.
即ち、第１定温度制御回路３は第１抵抗体2uとこの第
１抵抗体2uの温度設定用抵抗５とブリッジ抵抗6,7とか
らなるブリッジ回路８と、制御回路９とを備えている。
又、第２定温度制御回路４は第２抵抗体2dとこの第２抵
抗体2dの温度設定用抵抗10とブリッジ抵抗11,12と可変
抵抗13とからなるブリッジ回路14と、制御回路15とを備
えている。尚、可変抵抗13は導管１における流体Ｆの流
量がゼロのとき、ブリッジ回路8,14のそれぞれの出力が
互いに等しくなるように調整するものである。又、抵抗
5,6,7,10,11,12,13は第１抵抗体2u,第２抵抗体2dに比べ
て温度係数が十分小さくしてある。That is, the first constant temperature control circuit 3 includes a first resistor 2u, a bridge circuit 8 including a temperature setting resistor 5 of the first resistor 2u, and bridge resistors 6 and 7, and a control circuit 9. .
The second constant temperature control circuit 4 includes a second resistor 2d, a bridge circuit 14 including a temperature setting resistor 10, bridge resistors 11, 12 and a variable resistor 13 of the second resistor 2d, a control circuit 15, It has. The variable resistor 13 adjusts the outputs of the bridge circuits 8 and 14 to be equal to each other when the flow rate of the fluid F in the conduit 1 is zero. Also resistance
5, 6, 7, 10, 11, 12 and 13 have sufficiently smaller temperature coefficients than the first resistor 2u and the second resistor 2d.
そして、上記第１抵抗体2u,第２抵抗体2dは、第１定
温度制御回路３、第２定温度制御回路４によってそれぞ
れ供給される電流Iu,Idが流れることによって第１抵抗
体2u,第２抵抗体2dにそれぞれ発生する磁界Φu,Φｄの
向きが導管１内を流れる流体Ｆの向きと逆になるように
（第２図（Ａ）参照）、前記第１定温度制御回路３、第
２定温度制御回路４にそれぞれ接続してある。The first resistor 2u and the second resistor 2d are connected to the first resistor 2d by the currents I u and I d supplied by the first constant temperature control circuit 3 and the second constant temperature control circuit 4, respectively. The first constant temperature is adjusted so that the directions of the magnetic fields Φ u and Φ d generated in the second resistor 2 d and the second resistor 2 d are opposite to the directions of the fluid F flowing in the conduit 1 (see FIG. 2A). They are connected to the control circuit 3 and the second constant temperature control circuit 4, respectively.
16,17はそれぞれ加算回路，減算回路であり、ブリッ
ジ回路8,14の出力点18,19にそれぞれ出力される電位P1,
P2をそれぞれ入力とし、前者16からは加算出力としてP1
＋P2が、又、後者17からは減算出力としてP1−P2がそれ
ぞれ出力される。20は除算回路であり、加算回路24及び
減算回路からの出力を入力とし、除算出力として（P1−
P2）／（P1＋P2）を出力する。そして、この出力（P1−
P2）／（P1＋P2）は、導管１内を流れる流体Ｆの質量流
量に比例しているので、これに適宜の定数を乗ずること
により、導管１内を流れる流体Ｆの質量流体を得ること
ができる。尚、21は出力端子である。Reference numerals 16 and 17 denote addition circuits and subtraction circuits, respectively. The potentials P 1 and P 1 output at the output points 18 and 19 of the bridge circuits 8 and 14, respectively.
P 2 is used as an input, and P 1 is used as an addition output from the former 16.
+ P 2 , and the latter 17 outputs P 1 -P 2 as a subtraction output. Reference numeral 20 denotes a division circuit which receives the output from the addition circuit 24 and the output from the subtraction circuit as input and calculates (P 1 −
P 2) to output a / (P 1 + P 2) . Then, this output (P 1 −
Since P 2 ) / (P 1 + P 2 ) is proportional to the mass flow rate of the fluid F flowing in the conduit 1, the mass fluid of the fluid F flowing in the conduit 1 is multiplied by an appropriate constant. Obtainable. Incidentally, 21 is an output terminal.
而して、上記構成のマスフローメータにおいては、導
管１に巻設された２つの抵抗体2u,2dにそれぞれ生ずる
Φu,Φｄの向きが導管１内を流れる流体Ｆの方向と逆に
なるように、抵抗体2u,2dに電流Iu,Idを流すようしてい
るので、第３図（Ａ）に示すように、ノイズレベルが極
めて低い出力信号Ｋを得ることができる。従って、従来
のマスフローメータと異なり、ノイズフィルタを用いな
くても電圧変動が小さいノイズレベルが極めて低い出力
を得ることができるので、高速応答性をもって流量測定
を行うことができる。Thus, in the mass flow meter having the above configuration, the directions of Φ u and Φ d generated in the two resistors 2 u and 2 d wound around the conduit 1 are opposite to the directions of the fluid F flowing through the conduit 1. Since the currents I u and I d are caused to flow through the resistors 2u and 2d, an output signal K having an extremely low noise level can be obtained as shown in FIG. 3 (A). Therefore, unlike a conventional mass flow meter, an output with a small noise level and a very low noise level can be obtained without using a noise filter, so that the flow rate can be measured with a high-speed response.
尚、ここで、第２図及び第３図について説明すると、
第２図（Ａ）〜（Ｄ）は２つの抵抗体2u,2dに電流Iu,Id
をそれぞれ供給する場合における電流の供給方向と、電
流Iu,Idによって各抵抗体2u,2dにそれぞれ生じる磁界Φ
u,Φｄの向きと、導管１内を流れる流体Ｆの方向とを示
し、そのうち、（Ｂ）〜（Ｄ）は比較例を示す。又、第
３図（Ａ）〜（Ｄ）は第２図（Ａ）〜（Ｄ）の各場合に
おける出力信号の時間的変化を示す波形図で、そのう
ち、（Ｂ）〜（Ｄ）は比較例を示す。これらの図から、
比較例においては、ノイズレベルが極めて高いことが判
る。2 and 3 will now be described.
FIG. 2 (A) ~ (D) two resistors 2u, 2d current I u, I d
And the magnetic field Φ generated in each of the resistors 2u and 2d by the currents I u and I d , respectively.
u, and [Phi d orientation, indicates the direction of the fluid F flowing through the conduit 1, of which, (B) ~ (D) shows a comparison example. FIGS. 3 (A) to 3 (D) are waveform diagrams showing temporal changes of output signals in each case of FIGS. 2 (A) to 2 (D). Here is an example. From these figures,
In the comparative example, it can be seen that the noise level is extremely high.
本発明は、上述の実施例に限られるものではなく、例
えば抵抗体2u,2dを導管１に対して上記図示例以外の方
向に巻回してもよく、又、抵抗体2u,2dとして傍熱形感
熱コイルを用いてもよい。The present invention is not limited to the above-described embodiment. For example, the resistors 2u and 2d may be wound around the conduit 1 in a direction other than the above-described example. A shaped thermal coil may be used.
以上説明したように、本発明に係るマスフローメータ
は、流体が流れる導管に巻設された２つの抵抗体にそれ
ぞれ生ずる磁界の向きが前記流体の流れる方向と逆にな
るように、両定温度制御回路から各抵抗体に制御電流を
供給すると共に、加算回路、減算回路および除算回路を
設け、両定温度制御回路からの減算出力を加算出力で除
算出力を得るようにしているので、高速応答で精度よ
く、流体の流量を測定することができる。As described above, the mass flow meter according to the present invention has two constant temperature controls such that the directions of the magnetic fields generated in the two resistors wound around the conduit through which the fluid flows are opposite to the directions in which the fluid flows. A control current is supplied to each resistor from the circuit, and an addition circuit, a subtraction circuit, and a division circuit are provided. The flow rate of the fluid can be accurately measured.
第１図は本発明の一実施例に係るマスフローメータの構
成図である。 第２図（Ａ）〜（Ｄ）は２つの抵抗体に電流をそれぞれ
供給する場合における電流の供給方向と、前記電流によ
って各抵抗体にそれぞれ生じる磁界の向きと、導管内を
流れる流体の方向とを示す説明図、第３図（Ａ）〜
（Ｄ）は出力信号の時間的変化を示す波形図である。 １……導管、2u,2d……抵抗体、Ｆ……流体、Iu,Id……
電流、Φu,Φｄ……磁界。FIG. 1 is a configuration diagram of a mass flow meter according to one embodiment of the present invention. 2 (A) to 2 (D) show directions of current supply when current is supplied to each of two resistors, directions of magnetic fields generated in each of the resistors by the current, and directions of fluid flowing in the conduit. FIG. 3A to FIG.
(D) is a waveform diagram showing a temporal change of the output signal. 1 ...... conduit, 2u, 2d ...... resistor, F ...... fluid, I u, I d ......
Current, Φ u , Φ d ... magnetic field.
Claims (1)
なる２つの抵抗体を互いに独立させて間隔をおいて巻設
したマスフローメータにおいて、前記２つの抵抗体にそ
れぞれ生ずる磁界の向きが前記流体の流れる方向と逆向
きになるように、かつ、前記両抵抗体の温度が常に所定
の温度で相等しくなるように、前記各抵抗体にそれぞれ
制御電流を供給する２つの定温度制御回路を設けると共
に、その両定温度制御回路からの出力電位を加算する加
算回路と、一方の前記定温度制御回路の出力電位から他
方の前記定温度制御回路の出力電位を減算する減算回路
と、前記減算回路からの減算出力を前記加算回路からの
加算出力で除算する除算回路とを設けてなることを特徴
とするマスフローメータ。1. A mass flow meter in which two resistors made of a temperature-sensitive resistance wire are wound around a conduit through which a fluid flows at a distance from each other independently of each other. Two constant temperature control circuits for supplying a control current to each of the resistors are provided so as to be opposite to the flowing direction of the resistors and so that the temperatures of the resistors are always equal at a predetermined temperature. An addition circuit that adds output potentials from the two constant temperature control circuits, a subtraction circuit that subtracts an output potential of the other constant temperature control circuit from an output potential of one of the constant temperature control circuits, and the subtraction circuit. And a division circuit for dividing a subtraction output from the adder by an addition output from the addition circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63142264A JP2841199B2 (en) | 1988-06-09 | 1988-06-09 | Mass flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63142264A JP2841199B2 (en) | 1988-06-09 | 1988-06-09 | Mass flow meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01311231A JPH01311231A (en) | 1989-12-15 |
| JP2841199B2 true JP2841199B2 (en) | 1998-12-24 |
Family
ID=15311299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63142264A Expired - Lifetime JP2841199B2 (en) | 1988-06-09 | 1988-06-09 | Mass flow meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2841199B2 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61128123A (en) * | 1984-11-27 | 1986-06-16 | Esutetsuku:Kk | Mass flow meter |
-
1988
- 1988-06-09 JP JP63142264A patent/JP2841199B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01311231A (en) | 1989-12-15 |
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