JPS6126918Y2 - - Google Patents
Info
- Publication number
- JPS6126918Y2 JPS6126918Y2 JP16862979U JP16862979U JPS6126918Y2 JP S6126918 Y2 JPS6126918 Y2 JP S6126918Y2 JP 16862979 U JP16862979 U JP 16862979U JP 16862979 U JP16862979 U JP 16862979U JP S6126918 Y2 JPS6126918 Y2 JP S6126918Y2
- Authority
- JP
- Japan
- Prior art keywords
- differential pressure
- measurement
- temperature
- pressure
- pressure gauge
- 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
Links
- 239000007788 liquid Substances 0.000 claims description 27
- 238000005259 measurement Methods 0.000 claims description 27
- 230000005484 gravity Effects 0.000 claims description 7
- 238000007789 sealing Methods 0.000 claims description 5
- 239000004065 semiconductor Substances 0.000 claims description 4
- 239000012530 fluid Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 4
- 238000000605 extraction Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Description
【考案の詳細な説明】
本考案は密度計または液面計の一部を構成する
差圧計に関するものである。[Detailed Description of the Invention] The present invention relates to a differential pressure gauge that constitutes a part of a density meter or a liquid level gauge.
流体の密度または液面の高さを測定する計器の
一種として、鉛直管内の上下２点における圧力を
差圧計へ導いてこれらを求めるようにした差圧式
の密度計および液面計が実用的なものとして一般
に知られている。そして、この種の計器は、その
鉛直管内の上下２点と差圧計とが伝達媒体として
の液体を内封した一対のキヤピラリ管によつて連
結されており、これらのキヤピラリ管によつて差
圧計へ導かれた検出圧力を差圧計内に設けた感圧
素子の両面によつてそれぞれ受圧し、この感圧素
子の面上へ固着したストレンゲージが呈する電気
的抵抗の変化を公知の方法で検知してその大きさ
によつて圧力差を求めるように構成されている。 As a type of instrument for measuring the density of a fluid or the height of the liquid level, a differential pressure type density meter and liquid level meter, which calculate the pressure at two points above and below in a vertical pipe by guiding it to a differential pressure gauge, are practical. It is generally known as In this type of instrument, the two points above and below in the vertical pipe and the differential pressure gauge are connected by a pair of capillary tubes that contain liquid as a transmission medium. The detected pressure introduced into the pressure sensor is received by both sides of the pressure sensing element installed in the differential pressure gauge, and the change in electrical resistance exhibited by the strain gauge fixed on the surface of this pressure sensing element is detected by a known method. The pressure difference is determined based on the magnitude of the pressure difference.
ところで、この種の計器では、上下の測定点間
の高さの差に相当するキヤピラリ管内封液の重量
が管内の圧力に影響を与えないようにするため
に、差圧計に零点調節機構を設けて修正するよう
に構成されている。しかしながら測定時における
流体の温度変化によつて内封液が膨張、収縮して
その比重が変化し、これによつて管内の圧力が増
減するが、上記の修正はこの増減分までを補償す
ることができなかつた。 By the way, in this type of instrument, the differential pressure gauge is equipped with a zero point adjustment mechanism in order to prevent the weight of the sealing liquid in the capillary tube, which corresponds to the height difference between the upper and lower measurement points, from affecting the pressure inside the tube. It is configured to be corrected. However, due to temperature changes in the fluid during measurement, the internal liquid expands and contracts, causing its specific gravity to change, which causes the pressure inside the pipe to increase and decrease, but the above correction can only compensate for this increase and decrease. I couldn't do it.
本考案は以上のような点に鑑みなされたもの
で、高さの異なる２点に測定部を有し、この各測
定部における検出圧力を伝達する内封液を封入し
た一対のキヤピラリ管によつて各測定部との間を
連結された密度・液面測定用差圧計において、各
検出圧力を表裏両面に対向させて受圧する感圧素
子と、この感圧素子に付設されかつ半導体により
形成されたストレンゲージと、このストレンゲー
ジを要素として構成されたブリツジ回路と、内封
液の比重が呈する温度変化係数α、各測定部の高
さの差ｈ、および差圧計の全測定範囲Psを含む
〓〓〓〓〓
係数α・ｈ／Ｐｓにより算出できる値の温度補償機能を
有しかつブリツジ回路への電圧印加回路中へ直列
に挿入された感圧素子と可変抵抗器との並列結線
による温度補償回路とを設けることにより、測定
時の温度変化にかゝわらず常に正確な測定値を求
めることを可能ならしめた密度・液面測定用差圧
計を提供するものである。 The present invention was developed in view of the above points, and has measurement sections at two different heights, and uses a pair of capillary tubes filled with internal liquid to transmit the detected pressure at each measurement section. In the differential pressure gauge for density/liquid level measurement, which is connected to each measurement part by a pressure sensing element that receives each detected pressure on both the front and back surfaces, and a pressure sensing element attached to this pressure sensing element and made of a semiconductor. The strain gauge, the bridge circuit configured with this strain gauge as an element, the temperature change coefficient α exhibited by the specific gravity of the sealed liquid, the height difference h of each measurement part, and the entire measurement range Ps of the differential pressure gauge are included. 〓〓〓〓〓
A temperature compensation circuit is provided which has a temperature compensation function with a value that can be calculated by the coefficient α・h/Ps and is formed by connecting a pressure sensitive element and a variable resistor in parallel, which are inserted in series into the voltage application circuit to the bridge circuit. This provides a differential pressure gauge for density/liquid level measurement that makes it possible to always obtain accurate measured values regardless of temperature changes during measurement.
以下、その構成等を図に示す実施例により詳細
に説明する。 Hereinafter, its configuration and the like will be explained in detail with reference to embodiments shown in the drawings.
本実施例は本考案を密度計に実施した例を示
し、第１図は、これを実施した密度計の概要構成
図、第２図はおなじく電気回路図である。図にお
いて、被測定流体の流路内に設けた鉛直管１に
は、符号ａおよびｂで示す上下２個の測定部が設
定され、これらの測定部ａ，ｂの間には高さの差
ｈが与えられている。そして、これらの測定部
ａ，ｂには、それぞれ差圧取出しタツプ２および
３が設けられており、これらの差圧取出しタツプ
２，３はシリコン等の伝導媒体を内封した別々の
キヤピラリ管４および５によつて差圧計６と連結
されている。そして差圧計６の内部には、キヤピ
ラリ管４，５内の内封液によつて差圧計６へ伝達
される流体の圧力すなわち測定部ａ，ｂの圧力を
表裏両面に対向させて受圧するシリコンダイアフ
ラム等の半導体感圧素子７が設けられている。ま
た、この感圧素子７の一面または表裏両面には、
半導体によるストレンゲージ８および９が貼着に
よるかあるいは拡散状態で一体的に付設されてお
り、このストレンゲージ８，９と固定抵抗１０，
１１とによつてブリツジ回路１２が形成されてい
る。さらに、このブリツジ回路１２への電圧印加
回路中には、感温素子の一例として示すサーミス
タ１３と補償状況設定用の可変抵抗器１４とを並
列に結線した温度補償回路１５が直列に挿入して
設けられており、サーミスタ１３をストレンゲー
ジ８，９と同一部位へ封入する等の手段により、
サーミスタ１３と前記ストレンゲージ８，９が同
時に温度の影響を受けるごとく構成されている。
なお、１６は電圧供給回路を含む増幅器である。 This embodiment shows an example in which the present invention is implemented in a density meter, and FIG. 1 is a schematic configuration diagram of a density meter in which this invention is implemented, and FIG. 2 is an electric circuit diagram. In the figure, a vertical pipe 1 installed in the flow path of the fluid to be measured has two upper and lower measurement sections indicated by symbols a and b, and there is a height difference between these measurement sections a and b. h is given. These measurement parts a and b are provided with differential pressure extraction taps 2 and 3, respectively, and these differential pressure extraction taps 2 and 3 are connected to separate capillary tubes 4 that contain a conducting medium such as silicon. and 5 are connected to the differential pressure gauge 6. Inside the differential pressure gauge 6, there is silicon which faces the front and back to receive the pressure of the fluid transmitted to the differential pressure gauge 6 by the internal liquid in the capillary tubes 4 and 5, that is, the pressure of the measurement parts a and b. A semiconductor pressure sensitive element 7 such as a diaphragm is provided. In addition, on one side or both the front and back sides of this pressure sensitive element 7,
Semiconductor strain gauges 8 and 9 are integrally attached by adhesion or in a diffused state, and the strain gauges 8 and 9 and the fixed resistor 10,
11 form a bridge circuit 12. Further, in the voltage application circuit to this bridge circuit 12, a temperature compensation circuit 15 is inserted in series, in which a thermistor 13 shown as an example of a temperature sensing element and a variable resistor 14 for setting the compensation status are connected in parallel. By means such as enclosing the thermistor 13 in the same location as the strain gauges 8 and 9,
The thermistor 13 and the strain gauges 8 and 9 are constructed so as to be affected by temperature at the same time.
Note that 16 is an amplifier including a voltage supply circuit.
そして、前記ストレンゲージ８，９の温度変化
に応ずる抵抗値の変動を補償するため、温度補償
回路１５により、以下述べる計算式によつて導か
れた補償係計αｃ＝α・ｈ／Ｐｓによつて算出できる値
の温度補償機能が設けられている。 In order to compensate for variations in resistance values of the strain gauges 8 and 9 due to temperature changes, the temperature compensation circuit 15 uses a compensation coefficient αc=α·h/Ps derived by the calculation formula described below. A temperature compensation function is provided for the value that can be calculated based on the temperature.
すなわち、キヤピラリ管４，５中の内封液温度
がt1からt2へと変化した場合に、温度t1における
内封液の比重をr1、差圧をΔP1とし、温度t2にお
ける内封液の比重をr2、差圧をΔP2とすると、次
の式(1)が得られる。 That is, when the temperature of the sealed liquid in the capillary tubes 4 and 5 changes from t 1 to t 2 , the specific gravity of the sealed liquid at temperature t 1 is r 1 and the differential pressure is ΔP 1 , and at temperature t 2 When the specific gravity of the sealing liquid is r 2 and the differential pressure is ΔP 2 , the following equation (1) is obtained.
ΔP2−ΔP1＝（r2−r1）ｈ
∴ ΔP2＝（r2−r1）ｈ＋ΔP1 …(1)
ここで、内封液の比重変化が温度の変化に比例
していることが明らかであるから、αを内封液の
比重が呈する温度変化係数とすると、次式が成立
する。 ΔP 2 −ΔP 1 = (r 2 − r 1 )h ∴ ΔP 2 = (r 2 − r 1 )h+ΔP 1 …(1) Here, the change in specific gravity of the sealed liquid is proportional to the change in temperature. Since it is clear that α is the temperature change coefficient exhibited by the specific gravity of the sealing liquid, the following equation holds true.
ΔP2＝α（t2−t1）ｈ＋ΔP1
またここで、t1を基準温度とし、温度t2のとき
の測定誤差をｐとすると次式(2)が成立する。 ΔP 2 =α(t 2 −t 1 )h+ΔP 1 Here, if t 1 is the reference temperature and the measurement error at temperature t 2 is p, the following equation (2) holds true.
ｐ＝α・t2・ｈ …(2)
さらに、差圧計６の全測定範囲をPs、補償量
をPcとすると、全測定範囲Psにおいて測定誤差
の補償がなされるためには次式(3)が成立すればよ
い。 p=α・t 2・h …(2) Furthermore, if the entire measurement range of the differential pressure gauge 6 is Ps and the compensation amount is Pc, then in order to compensate for measurement errors in the entire measurement range Ps, the following equation (3 ) should hold true.
Ｐ／Ｐｓ＋Pc＝０ …(3)
そこで、式(2)を式(3)に代入すると
Pc＝−αｈ／Ｐｓt2
これにより前記補償係数αcとして示した次式
(4)が得られる。 P/Ps+Pc=0...(3) Then, by substituting equation (2) into equation (3), Pc=-αh/Pst 2 This gives the following equation, which is expressed as the compensation coefficient α c :
(4) is obtained.
αc＝αｈ／Ｐｓ …(4)
以上のごとく構成された密度計において、測定
部ａ，ｂにおける流体の圧力はそれぞれ差圧取出
しタツプ２，３からキヤピラリ管４，５に入り、
管内の内封液によつて差圧計６へ伝達され、その
圧力が差圧計６内の感圧素子７の表裏両面に作用
する。そして感圧素子７両面の差圧による変位
は、ストレンゲージ８，９によつて抵抗変化に変
換されて発信されるので、これを読み取ることに
よつて流体の密度を知ることができる。そして、
この測定時には、内封液の温度変化によつてスト
レンゲージ８，９の抵抗値が変動するが、これと
同時に温度補償回路１５のサーミスタ１３もこの
温度変化の影響を受けるので、同回路１５の温度
〓〓〓〓〓
特性を式(4)の補償係数に基づいて定めることによ
り、ブリツジ回路１２に対する印加電圧が温度に
応じて調節される。したがつて、ストレンゲージ
８，９へ印加される電圧が温度変化に応じストレ
ンゲージ８，９の抵抗値変動を相殺する方向へ変
化することによつて、温度変化に対応した補償が
行なわれて温度変化に影響されない正しい密度を
求めることができる。 α c =αh/Ps (4) In the density meter configured as above, the pressure of the fluid in the measurement parts a and b enters the capillary tubes 4 and 5 from the differential pressure extraction taps 2 and 3, respectively, and
The pressure is transmitted to the differential pressure gauge 6 by the sealing liquid in the tube, and the pressure acts on both the front and back surfaces of the pressure sensing element 7 within the differential pressure gauge 6. The displacement due to the differential pressure on both sides of the pressure sensitive element 7 is converted into a resistance change and transmitted by the strain gauges 8 and 9, and by reading this, the density of the fluid can be determined. and,
During this measurement, the resistance values of the strain gauges 8 and 9 fluctuate due to temperature changes in the sealed liquid, but at the same time, the thermistor 13 of the temperature compensation circuit 15 is also affected by this temperature change. Temperature〓〓〓〓〓
By determining the characteristics based on the compensation coefficient of equation (4), the voltage applied to the bridge circuit 12 is adjusted in accordance with the temperature. Therefore, by changing the voltage applied to the strain gauges 8, 9 in a direction that cancels out the resistance fluctuations of the strain gauges 8, 9 in accordance with the temperature change, compensation corresponding to the temperature change is performed. It is possible to determine the correct density that is not affected by temperature changes.
なお、本実施例においては本考案に係る差圧計
を鉛直管に付設したが、鉛直管の代りに、液体を
貯蔵したタンクに付設し、タンク壁面の上下２箇
所を貫いて導かれる各圧力の差を測定してもよ
い。また、本考案は密度計ばかりでなく、液面の
高さを測定する液面計にも同様に実施することが
できる。 In this example, the differential pressure gauge according to the present invention was attached to a vertical pipe, but instead of the vertical pipe, it was attached to a tank storing liquid, and each pressure gauge introduced through the upper and lower parts of the tank wall was measured. Differences may also be measured. Further, the present invention can be applied not only to a density meter but also to a liquid level meter that measures the height of a liquid level.
以上の説明により明らかなように、本考案によ
れば、高さの異なる２点に測定部を有する密度・
液面測定計器における差圧計において、感圧素子
に付設したストレンゲージを要素として構成され
たブリツジ回路に対し電圧印加を行なう回路中へ
温度補償回路を挿入し、この温度補償回路に、あ
らかじめ設定された数値の係数により算出できる
値の温度補償機能を具備させることにより、測定
時における流体の温度変化に対応する補償がなさ
れ、温度変化にかゝわらず常にきわめて正確な測
定値を求めることができ、その効果がきわめて大
きい。 As is clear from the above explanation, according to the present invention, the density sensor having the measurement parts at two different heights can be used.
In a differential pressure gauge used as a liquid level measuring instrument, a temperature compensation circuit is inserted into the circuit that applies voltage to a bridge circuit configured using a strain gauge attached to a pressure-sensitive element as an element, and a By providing a temperature compensation function for values that can be calculated using numerical coefficients, compensation is made for fluid temperature changes during measurement, making it possible to always obtain extremely accurate measured values regardless of temperature changes. , the effect is extremely large.
第１図および第２図は本考案に係る密度・液面
測定用差圧計を示し、第１図はその概要構成図、
第２図はおなじく電気回路図である。
４，５……キヤピラリ管、６……差圧計、７…
…感圧素子、８，９……ストレンゲージ、１２…
…ブリツジ回路、１３……感温素子、１４……可
変抵抗器、１５……温度補償回路、ａ，ｂ……測
定部。
〓〓〓〓〓
Figures 1 and 2 show a differential pressure gauge for measuring density and liquid level according to the present invention, and Figure 1 is a schematic configuration diagram thereof;
FIG. 2 is also an electrical circuit diagram. 4, 5... Capillary tube, 6... Differential pressure gauge, 7...
...Pressure sensitive element, 8, 9...Strain gauge, 12...
... Bridge circuit, 13 ... Temperature sensing element, 14 ... Variable resistor, 15 ... Temperature compensation circuit, a, b ... Measurement section. 〓〓〓〓〓
Claims (1)
部における検出圧力を伝達する内封液を封入した
一対のキヤピラリ管によつて前記各測定部との間
を連結された密度・液面測定用差圧計において、
前記各検出圧力を表裏両面に対向させて受圧する
感圧素子と、この感圧素子に付設されかつ半導体
により形成されたストレンゲージと、このストレ
ンゲージを要素として構成されたブリツジ回路
と、前記内封液の比重が呈する温度変化係計α、
前記各測定部の高さの差ｈ、および前記差圧計の
全測定範囲Psを含む係数α・ｈ／Ｐｓにより算出できる 値の温度補償機能を有しかつ前記ブリツジ回路へ
の電圧印加回路中へ直列に挿入された感温素子と
可変抵抗器との並列結線による温度補償回路とを
設けたことを特徴とする密度・液面測定用差圧
計。[Claims for Utility Model Registration] Measuring sections are provided at two points at different heights, and the measurement sections are connected to each other by a pair of capillary tubes filled with an internal liquid that transmits the detected pressure at each measuring section. In the differential pressure gauge for density and liquid level measurement connected between
A pressure-sensitive element that receives each of the detected pressures with its front and back surfaces facing each other, a strain gauge attached to this pressure-sensitive element and formed of a semiconductor, a bridge circuit configured with this strain gauge as an element, and Temperature change coefficient α expressed by the specific gravity of the sealing liquid,
It has a temperature compensation function of a value that can be calculated by a coefficient α·h/Ps that includes the height difference h of each of the measurement parts and the entire measurement range Ps of the differential pressure gauge, and is connected to the voltage application circuit to the bridge circuit. A differential pressure gauge for measuring density and liquid level, characterized by having a temperature compensation circuit formed by connecting a temperature sensing element inserted in series and a variable resistor in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16862979U JPS6126918Y2 (en) | 1979-12-07 | 1979-12-07 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16862979U JPS6126918Y2 (en) | 1979-12-07 | 1979-12-07 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5686548U JPS5686548U (en) | 1981-07-11 |
| JPS6126918Y2 true JPS6126918Y2 (en) | 1986-08-12 |
Family
ID=29679457
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16862979U Expired JPS6126918Y2 (en) | 1979-12-07 | 1979-12-07 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6126918Y2 (en) |
-
1979
- 1979-12-07 JP JP16862979U patent/JPS6126918Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5686548U (en) | 1981-07-11 |
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