JPH0449893B2 - - Google Patents
Info
- Publication number
- JPH0449893B2 JPH0449893B2 JP59249861A JP24986184A JPH0449893B2 JP H0449893 B2 JPH0449893 B2 JP H0449893B2 JP 59249861 A JP59249861 A JP 59249861A JP 24986184 A JP24986184 A JP 24986184A JP H0449893 B2 JPH0449893 B2 JP H0449893B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- fluid
- heat
- coil
- conduit
- 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
- 239000012530 fluid Substances 0.000 claims description 33
- 238000011144 upstream manufacturing Methods 0.000 claims description 5
- 230000004044 response Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000004043 responsiveness Effects 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
- G01F1/68—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 thermal effects
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Details Of Flowmeters (AREA)
- Measuring Volume Flow (AREA)
Description
【発明の詳細な説明】
＜産業上の利用分野＞
本発明は、導管中を流れる流体の質量流量を測
定する質量流量計に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a mass flow meter for measuring the mass flow rate of a fluid flowing in a conduit.
＜従来の技術＞
前記質量流量計として、例えば導管の上流側と
下流側にそれぞれ温度係数の大なる感熱コイルを
配し、各感熱コイルに供給する電流値を一定に保
持し、流体が流れることによつて変化する感熱部
分の温度分布を検出することにより流量測定を行
なうもの（例えば、特公昭56−23094号公報）や、
流体温度を調節することにより通過流体を条件づ
け、流体が通過する時の熱交換作用において流体
の温度を異なる温度値に変更し、これら温度調節
と温度変更段階のうちの少なくとも一方の段階で
費されたエネルギーを表示するようにして流量測
定を行なうもの（例えば、特開昭59−18423号公
報）がある。<Prior art> As the mass flowmeter, for example, heat-sensitive coils with large temperature coefficients are arranged on the upstream and downstream sides of a conduit, and the current value supplied to each heat-sensitive coil is held constant to allow fluid to flow. Those that measure the flow rate by detecting the temperature distribution of the heat-sensitive part that changes depending on the temperature (for example, Japanese Patent Publication No. 56-23094),
Conditioning the passing fluid by adjusting the fluid temperature, changing the temperature of the fluid to different temperature values in a heat exchange action as the fluid passes, and reducing the cost in at least one of the temperature adjustment and temperature modification steps. There is a method (for example, Japanese Patent Laid-Open No. 18423/1983) that measures the flow rate by displaying the energy generated.
しかしながら、前者は温度分布が変化する速さ
が導管やその被覆物の熱容量の影響をうけるため
応答性に欠ける欠点がある。また、後者は、応答
速度は前者に比べると良好であるが、動作原理が
熱線流速計と同一であるため、周囲温度の変化や
流体の熱容量の違い等によつてゼロ点が変動し易
いという欠点があり、この欠点をなくすため温調
回路を設けても回路構成が複雑になる割にはその
実効が上がりにくいという問題点がある。 However, the former has the disadvantage of lacking responsiveness because the speed at which the temperature distribution changes is affected by the heat capacity of the conduit and its covering. In addition, although the latter has a better response speed than the former, the operating principle is the same as that of a hot wire anemometer, so the zero point tends to fluctuate due to changes in ambient temperature or differences in the heat capacity of the fluid. There are drawbacks, and even if a temperature control circuit is provided to eliminate this drawback, there is a problem in that it is difficult to increase the effectiveness of the circuit even though the circuit configuration is complicated.
＜発明が解決しようとする問題点＞
本発明は、上述の事柄に留意してなされたもの
で、ゼロ点が変動せず、しかも応答速度が早い質
量流量計を提供することを目的とする。<Problems to be Solved by the Invention> The present invention has been made with the above-mentioned considerations in mind, and an object of the present invention is to provide a mass flowmeter in which the zero point does not fluctuate and the response speed is fast.
＜問題点を解決するための手段＞
上述の目的を達成するため、本発明では、流体
が流れる導管の上流側と下流側に前記流体の温度
に応じて抵抗値が変化する感熱コイルを設け、更
に、前記感熱コイルをそれぞれ含む定温度回路を
独立して設け、該定温度回路によつて両感熱コイ
ルの温度を常に相等しくかつ一定となるように制
御し、両感熱コイルに与えられるエネルギの差を
検出することにより、前記導管中の流体の質量流
量を測定するようにしている。<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention provides heat-sensitive coils whose resistance value changes depending on the temperature of the fluid on the upstream and downstream sides of the conduit through which the fluid flows, Furthermore, a constant temperature circuit containing each of the heat-sensitive coils is provided independently, and the constant-temperature circuit controls the temperature of both heat-sensitive coils so that they are always equal and constant, thereby controlling the energy given to both heat-sensitive coils. By detecting the difference, the mass flow rate of fluid in the conduit is determined.
＜作用＞
上述の構成においては、導管内に流体が流れて
いないときは、上流側と下流側の感熱コイルを同
一温度に保持するためのエネルギは相等しいか
ら、周囲温度の変化や導管内の流体の相違による
ゼロ点の影響は相殺される。また、導管内に流体
が流れているときは、上流側の感熱コイルは流体
に熱を奪われる。この結果、流体は加熱され温度
上昇するが、前記感熱コイルを所定温度に保持す
るには、ガスが流れていないときに比べて大なる
エネルギが必要となる。一方、下流側の感熱コイ
ルは前記加熱された流体から熱を受けることによ
り、該感熱コイルを所定温度に保持するには、ガ
スが流れていない状態に比べて小なるエネルギで
よいことになる。このとき生ずる前記両コイルに
供給されるエネルギの差は、そのときの流体の質
量流量に比例しているから、前記エネルギの差を
検出することにより質量流量を測定できるのであ
る。<Function> In the above configuration, when no fluid is flowing in the conduit, the energy required to maintain the upstream and downstream thermosensitive coils at the same temperature is equal, so changes in ambient temperature or Zero point effects due to fluid differences cancel out. Furthermore, when fluid is flowing in the conduit, heat is taken away from the upstream thermosensitive coil by the fluid. As a result, the fluid is heated and its temperature increases, but in order to maintain the heat-sensitive coil at a predetermined temperature, more energy is required than when no gas is flowing. On the other hand, since the heat-sensitive coil on the downstream side receives heat from the heated fluid, less energy is required to maintain the heat-sensitive coil at a predetermined temperature than when no gas is flowing. Since the difference in energy supplied to both coils that occurs at this time is proportional to the mass flow rate of the fluid at that time, the mass flow rate can be measured by detecting the difference in energy.
＜実施例＞
以下、本発明の一実施例を図面に基づいて説明
する。<Example> An example of the present invention will be described below based on the drawings.
図面は質量流量計の一構成例を示し、１はガス
等の流体Ｇが流れる導管で、矢印方向に流体Ｇが
流れる。Ru，Rdは導管１上の適当に離れた２点
にそれぞれ設けられる感熱コイル（以下、第１コ
イルRu、第２コイルRdという）で、鉄・ニツケ
ル合金等温度係数の大なる温度感応抵抗線より成
る。これは導管１中を流れる流体Ｇのが10c.c.／
minであり、そのわずかな変位をも検知するため
である。 The drawing shows an example of the configuration of a mass flowmeter, and 1 is a conduit through which a fluid G such as gas flows, and the fluid G flows in the direction of the arrow. Ru and Rd are heat-sensitive coils (hereinafter referred to as the first coil Ru and second coil Rd) respectively installed at two appropriately separated points on the conduit 1, and are temperature-sensitive resistance wires with a large temperature coefficient such as iron and nickel alloys. Consists of. This means that the fluid G flowing in conduit 1 is 10 c.c./
This is to detect even the slightest displacement.
Tu，Tdは第１コイルRu、第２コイルRdをそ
れぞれ含む定温度回路（以下、第１定温度回路
Tu、第２定温度回路Tdという）で、両定温度回
路Tu，Tdは同一部品より成り、第１コイルRu、
第２コイルRdが常に相等しくかつ一定温度にな
るようにするものである。（なお図では、第２定
温度回路Td側の構成部材の符号にはダツシユを
付す。）ここでは第１定温度回路Tuの構成につい
てのみ説明する。即ち、第１定温度回路Tuはブ
リツジ回路１０と、制御回路２０とスイツチング
素子３０と直流電源４０とから構成されており、
ブリツジ回路１０は第１コイルRuと、この第１
コイルRuの温度設定用抵抗１１と、ブリツジ抵
抗１２，１３とより成る。前記抵抗１１，１２，
１３は第１コイルTuに比べて温度係数が十分小
さいものが用いられる。Au（第２定温度回路Td
ではAd）、Ｂはそれぞれ第１コイルRu，Ruと抵
抗１１、ブリツジ抵抗１２と１３の接続点で、そ
の電位VA、VBは制御回路２０に入力される。 Tu and Td are constant temperature circuits (hereinafter referred to as the first constant temperature circuit) including the first coil Ru and the second coil Rd, respectively.
Tu, the second constant temperature circuit Td), both constant temperature circuits Tu and Td are made of the same parts, and the first coil Ru,
This is to ensure that the second coil Rd is always at the same and constant temperature. (In the figure, the symbols of the constituent members on the second constant temperature circuit Td side are indicated by dashes.) Here, only the configuration of the first constant temperature circuit Tu will be described. That is, the first constant temperature circuit Tu is composed of a bridge circuit 10, a control circuit 20, a switching element 30, and a DC power supply 40.
The bridge circuit 10 includes a first coil Ru and a first coil Ru.
It consists of a temperature setting resistor 11 for the coil Ru and bridge resistors 12 and 13. The resistors 11, 12,
The coil 13 used has a sufficiently smaller temperature coefficient than the first coil Tu. Au (second constant temperature circuit Td
In Ad), B is the connection point between the first coils Ru, Ru and the resistor 11, and the bridge resistors 12 and 13, respectively, and the potentials V A and V B are input to the control circuit 20.
前記制御回路２０は、例えば演算増幅器２１と
発振防止用のコンデンサ２２とから成り、前記演
算増幅器２１は前記電位VAとVBとを比較して両
者に差があるとき信号Ｐを出力する。 The control circuit 20 includes, for example, an operational amplifier 21 and an oscillation prevention capacitor 22. The operational amplifier 21 compares the potentials V A and V B and outputs a signal P when there is a difference between them.
スイツチング素子３０は例えばトランジスタよ
りなり、前記信号Ｐに基づいてスイツチング制御
を行なう。 The switching element 30 is made of a transistor, for example, and performs switching control based on the signal P.
次に、５０は第１定温度回路Tuの接続点Auの
電位V1と、第２定温度回路Tdの接続点Adの電位
V2をそれぞれ入力とし、両者の差を出力する出
力回路で、演算増幅器５１と、入力インピーダン
スを大きくするためのインピーダンス回路５２と
より成る。この出力回路５０の出力信号ｋは第１
コイルRu、第２コイルRdを同一温度かつ一定温
度にするため各電源４０，４０′から前記両コイ
ルRu，Rdにそれぞれ供給されるエネルギの差を
表わすとともに、この出力信号ｋの大きさは導管
１中を流れる流体Ｇの質量流量に比例している。 Next, 50 is the potential V 1 of the connection point Au of the first constant temperature circuit Tu and the potential of the connection point Ad of the second constant temperature circuit Td.
This is an output circuit that inputs V 2 and outputs the difference between the two, and is composed of an operational amplifier 51 and an impedance circuit 52 for increasing the input impedance. The output signal k of this output circuit 50 is the first
In order to keep the coil Ru and the second coil Rd at the same temperature and constant temperature, it represents the difference in energy supplied from each power source 40, 40' to the coils Ru and Rd, and the magnitude of this output signal k 1 is proportional to the mass flow rate of fluid G flowing through it.
上述のように構成した質量流量計において、導
管１内に流体Ｇが流れていないときは、第１コイ
ルRu、第２コイルRdにはブリツジ回路１０を介
して直流電源４０，４０′からのエネルギが与え
られるだけであり、両コイルRu，Rdは抵抗１
１，１１′によつてそれぞれ定められる温度に保
持される。そして、第１定温度回路Tu、第２定
温度回路Tdの抵抗１１，１１′の特性は等しいか
ら、前記両コイルRu，Rdの温度は相等しくな
る。このため、点Auの電位V1と、点Adの電位
V2とは相等しく、出力回路５０からの出力信号
ｋは零となり、流体Ｇが流れてないことを示す。 In the mass flowmeter configured as described above, when the fluid G is not flowing in the conduit 1, the first coil Ru and the second coil Rd receive energy from the DC power supplies 40, 40' via the bridge circuit 10. is given, and both coils Ru and Rd have a resistance of 1
1 and 11', respectively. Since the resistors 11 and 11' of the first constant temperature circuit Tu and the second constant temperature circuit Td have the same characteristics, the temperatures of both the coils Ru and Rd become equal. Therefore, the potential V 1 at point Au and the potential at point Ad
It is equal to V2 , and the output signal k from the output circuit 50 becomes zero, indicating that the fluid G is not flowing.
次に、導管１内に流体Ｇが流れているときは、
第１コイルRuは流体Ｇによつて熱を套われ、逆
に第２コイルRdは流体Ｇから熱を与えられる。
このため、第１コイルRuを所定温度に保持する
ため直流電源４０からのエネルギ供給が大とな
り、その結果、点Auの電位が上昇する。他方、
第２コイルRdを所定温度に保持する場合におい
て、流体Ｇから熱を与えられた分だけ直流電源４
０′からエネルギが少なくて済み、その結果、点
Adの電位は下がる。このため、出力回路５０に
入力される電圧V1，V2に差が生じ、出力信号ｋ
としてV1−V2が得られる。そして、前記V1−V2
は導管１内を流れる流体Ｇの質量流量に比例した
ものであるから、これに定数を乗ずることにより
流体の質量流量が得られる。 Next, when fluid G is flowing in conduit 1,
The first coil Ru receives heat from the fluid G, and conversely, the second coil Rd receives heat from the fluid G.
Therefore, in order to maintain the first coil Ru at a predetermined temperature, the energy supply from the DC power supply 40 increases, and as a result, the potential at the point Au increases. On the other hand,
When maintaining the second coil Rd at a predetermined temperature, the DC power supply 4 is heated by the amount of heat given from the fluid G.
From 0′, less energy is required, so that the point
The potential of Ad decreases. Therefore, a difference occurs between the voltages V 1 and V 2 input to the output circuit 50, and the output signal k
As such, V 1 −V 2 is obtained. And said V 1 −V 2
Since is proportional to the mass flow rate of the fluid G flowing in the conduit 1, the mass flow rate of the fluid can be obtained by multiplying this by a constant.
＜発明の効果＞
以上説明したように、本発明においては、温度
分布の変化を検出せず、導管の二点に設けた感熱
コイルの温度を常に相等しくかつ一定となるよう
に制御してそのとき両コイルに与えられるエネル
ギの差を検出するものがあるから、導管等の外的
要因に左右されないため、応答速度が早いととも
に、周囲温度の変化や導管中の流体種によるゼロ
点変動は相殺され、精度の高い質量流量計が得ら
れる。又、複雑な温度回路等を要しないため、構
成が簡略化され安価となる。<Effects of the Invention> As explained above, in the present invention, changes in temperature distribution are not detected, and the temperature of the heat-sensitive coils provided at two points on the conduit is always controlled to be equal and constant. Since there is a device that detects the difference in energy given to both coils, the response speed is fast because it is not affected by external factors such as the conduit, and zero point fluctuations due to changes in ambient temperature or the type of fluid in the conduit are canceled out. A highly accurate mass flowmeter can be obtained. Furthermore, since a complicated temperature circuit or the like is not required, the configuration is simplified and the cost is reduced.
図面は本発明に係る質量流量計の概略構成図で
ある。
１……導管、Ru，Rd……感熱コイル、Tu，
Td……定温度回路、Ｇ……ガス。
The drawing is a schematic configuration diagram of a mass flowmeter according to the present invention. 1... Conduit, Ru, Rd... Heat sensitive coil, Tu,
Td...constant temperature circuit, G...gas.
Claims (1)
体の温度に応じて抵抗値が変化する感熱コイルを
設け、更に、前記感熱コイルをそれぞれ含む定温
度回路を独立して設け、該定温度回路によつて両
感熱コイルの温度を常に相等しくかつ一定となる
ように制御し、両感熱コイルに与えられるエネル
ギの差を検出することにより前記導管中の流体の
質量流量を測定するようにしたことを特徴とする
質量流量計。1 Heat-sensitive coils whose resistance value changes depending on the temperature of the fluid are provided on the upstream and downstream sides of a conduit through which the fluid flows, and furthermore, constant-temperature circuits each containing the heat-sensitive coils are independently provided, and the constant-temperature circuit The temperature of both heat-sensitive coils is always controlled to be equal and constant, and the mass flow rate of the fluid in the conduit is measured by detecting the difference in energy given to both heat-sensitive coils. A mass flow meter featuring:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59249861A JPS61128123A (en) | 1984-11-27 | 1984-11-27 | Mass flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59249861A JPS61128123A (en) | 1984-11-27 | 1984-11-27 | Mass flow meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61128123A JPS61128123A (en) | 1986-06-16 |
| JPH0449893B2 true JPH0449893B2 (en) | 1992-08-12 |
Family
ID=17199278
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59249861A Granted JPS61128123A (en) | 1984-11-27 | 1984-11-27 | Mass flow meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61128123A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2631481B2 (en) * | 1987-12-08 | 1997-07-16 | 株式会社 リンテック | Mass flow meter and its measurement method |
| US4843881A (en) * | 1987-12-24 | 1989-07-04 | Aalborg Instruments & Controls | Fluid flow sensor system |
| JP2841199B2 (en) * | 1988-06-09 | 1998-12-24 | 株式会社エステック | Mass flow meter |
| JP2814379B2 (en) * | 1988-06-20 | 1998-10-22 | 忠弘 大見 | Mass flow controller |
| JPH0784650A (en) * | 1993-07-23 | 1995-03-31 | Hitachi Metals Ltd | Mass flow controller, its operation method and solenoid valve |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5149752A (en) * | 1974-10-25 | 1976-04-30 | Okura Denki Co Ltd | NETSUSHI KIRYURYOKEI |
| JPS5623094A (en) * | 1979-08-03 | 1981-03-04 | Toshiba Electric Equip Corp | Remote control unit |
| JPS5858417A (en) * | 1981-09-10 | 1983-04-07 | ロ−ベルト・ボツシユ・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Method and device for measuring quantity of fluid medium, which flow through fluid section and change in pulsatile form |
| JPS59136620A (en) * | 1982-12-30 | 1984-08-06 | ロ−ベルト・ボツシユ・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Measuring device for flow rate of fluid |
-
1984
- 1984-11-27 JP JP59249861A patent/JPS61128123A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5149752A (en) * | 1974-10-25 | 1976-04-30 | Okura Denki Co Ltd | NETSUSHI KIRYURYOKEI |
| JPS5623094A (en) * | 1979-08-03 | 1981-03-04 | Toshiba Electric Equip Corp | Remote control unit |
| JPS5858417A (en) * | 1981-09-10 | 1983-04-07 | ロ−ベルト・ボツシユ・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Method and device for measuring quantity of fluid medium, which flow through fluid section and change in pulsatile form |
| JPS59136620A (en) * | 1982-12-30 | 1984-08-06 | ロ−ベルト・ボツシユ・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング | Measuring device for flow rate of fluid |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61128123A (en) | 1986-06-16 |
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