JP2003057093A - Electrode for liquid level detector - Google Patents
Electrode for liquid level detectorInfo
- Publication number
- JP2003057093A JP2003057093A JP2001249749A JP2001249749A JP2003057093A JP 2003057093 A JP2003057093 A JP 2003057093A JP 2001249749 A JP2001249749 A JP 2001249749A JP 2001249749 A JP2001249749 A JP 2001249749A JP 2003057093 A JP2003057093 A JP 2003057093A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- liquid
- liquid level
- level detector
- conductor
- 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.)
- Pending
Links
Landscapes
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は電解質溶液の液面レ
ベル検出器に用いるための電極に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode for use in a liquid level detector for an electrolyte solution.
【０００２】[0002]
【従来の技術】従来の静電容量式液面レベルセンサで
は、電極から液面までの空中の静電容量変化を検出した
ものや、液そのものの液レベル変化による静電容量変化
を検出するものが多くを占める。この場合、周囲温度変
化や液温度変化に対する補正が必要であり、また液の比
誘電率の違いに対する補正も必要である。そのため検出
回路も複雑になり、電極の構造も基準電極を設けたり、
あるいは可動部分が必要であったりするため、小型省ス
ペース型形状にすることや、低コストにすることができ
ない。2. Description of the Related Art A conventional capacitance type liquid level sensor detects a change in capacitance in the air from an electrode to a liquid level, or a change in capacitance due to a change in liquid level of the liquid itself. Occupy most. In this case, it is necessary to correct for changes in ambient temperature and changes in liquid temperature, and also for differences in relative dielectric constant of the liquid. Therefore, the detection circuit becomes complicated, and the electrode structure has a reference electrode,
Alternatively, since a movable part is required, it is not possible to reduce the size and space and to reduce the cost.
【０００３】[0003]
【発明が解決しようとする課題】上述のように従来技術
では電極の構造などが複雑であり、製造コストも高く、
簡便で低価格な液面レベル検出器を構成することができ
ない。As described above, in the prior art, the structure of the electrodes is complicated and the manufacturing cost is high,
A simple and inexpensive liquid level detector cannot be constructed.
【０００４】本発明は被測定対象液が電解質溶液である
場合に、液の導電率の変化や比誘電率の変化に依存する
ことなく簡便で正確かつ低価格な液面レベル検出器の電
極を提供することを目的とする。The present invention provides a simple, accurate and low-cost electrode for a liquid level detector that does not depend on changes in the conductivity or relative permittivity of the liquid when the liquid to be measured is an electrolyte solution. The purpose is to provide.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に請求項１に記載する本発明の電極は、被測定対象の液
中浸漬の割合に応じて静電容量を変化させるため、棒状
導体の表面を誘電体で被膜した電極と、被測定対象液と
電気的に接続する導体電極で構成されていることを特徴
としている。以下、誘電体で被膜した電極を誘電体被膜
電極Ａ、液と接続するための導体電極を導体電極Ｂと説
明する。In order to achieve the above object, the electrode of the present invention described in claim 1 changes the electrostatic capacity according to the ratio of immersion in the liquid to be measured. It is characterized in that it is composed of an electrode whose surface is coated with a dielectric and a conductor electrode which is electrically connected to the liquid to be measured. Hereinafter, an electrode coated with a dielectric will be referred to as a dielectric coated electrode A, and a conductor electrode for connecting with a liquid will be referred to as a conductor electrode B.
【０００６】請求項１に記載する電極では誘電体被膜電
極Ａの中心導体Ａ１と被測定液の間に誘電体被膜Ａ２に
よる静電容量が生じる。一般に静電容量は電極間の比誘
電率と電極面積に比例し、電極間の距離に反比例する。
このため、電極に同一の誘電体材料で一定厚みの被膜を
形成すると、静電容量は電極が液中に浸漬される長さ
（面積）に比例する。液は単なる電極としてしか使用し
ないため液の導電率の変化や比誘電率の変化に依存しな
い。In the electrode according to the first aspect, a capacitance is generated between the central conductor A1 of the dielectric coating electrode A and the liquid to be measured due to the dielectric coating A2. Generally, the electrostatic capacitance is proportional to the relative permittivity between the electrodes and the electrode area, and is inversely proportional to the distance between the electrodes.
Therefore, when a film having a constant thickness is formed on the electrode with the same dielectric material, the capacitance is proportional to the length (area) of the electrode immersed in the liquid. Since the liquid is used only as an electrode, it does not depend on the change in conductivity or the change in relative permittivity of the liquid.
【０００７】請求項１に記載する電極において、導体電
極Ｂは被測定液と電気的に接続するためだけのものであ
るため、あらゆる構造をとることが出来ることを特徴と
している。すなわち、誘電体被膜電極と導体電極を２本
配置する構造や、導体電極を円筒形状にして中心に誘電
体被膜電極を配置する構造や、タンクを金属または導体
で形成し、タンクそのものを導体電極とすることは当然
その技術的範囲に含まれる。そのために、小型省スペー
スで、測定範囲あるいはタンクの深さに合わせて自由な
寸法で製造することができることも特徴としている。In the electrode described in claim 1, since the conductor electrode B is only for electrically connecting to the liquid to be measured, it is characterized in that it can have any structure. That is, a structure in which two dielectric coating electrodes and a conductor electrode are arranged, a structure in which the conductor electrode is cylindrical and the dielectric coating electrode is arranged in the center, a tank is formed of metal or a conductor, and the tank itself is a conductor electrode. Of course, that is included in the technical scope. Therefore, it is also characterized in that it can be manufactured in a small size and in a space-saving manner and with free dimensions according to the measurement range or the depth of the tank.
【０００８】請求項２に記載する電極は、誘電体被膜電
極Ａに被膜する誘電体被膜Ａ２の材質を高分子系樹脂と
することで比較的高い比誘電率が得られ、製造が簡単で
低コストの電極とすることが出来ることを特徴としてい
る。In the electrode described in claim 2, a relatively high relative permittivity can be obtained by using a polymer resin as the material of the dielectric coating A2 that coats the dielectric coating electrode A, and the manufacturing is simple and low. The feature is that it can be used as a cost electrode.
【０００９】請求項３に記載する電極は、誘電体被膜電
極Ａに被膜する誘電体被膜Ａ２の材質をフッ素樹脂とす
ることで、被測定液が粘性のある液体でも液が電極に付
着することなく正確な液面レベルを測定することができ
ることを特徴としている。According to the third aspect of the present invention, the material of the dielectric coating A2 that coats the dielectric coating electrode A is fluororesin, so that the liquid adheres to the electrode even if the measured liquid is a viscous liquid. It is characterized by being able to measure the liquid level accurately without the need for it.
【００１０】[0010]
【発明の実施の形態】以下、添付図面を参照して本発明
に依る液面レベル検出器用電極の実施形態を説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a liquid level detector electrode according to the present invention will be described below with reference to the accompanying drawings.
【００１１】請求項１又は２又は３に記載する電極の構
造は、誘電体被膜電極Ａは、中心導体Ａ１の表面を上部
の配線接続部Ｄを除いて誘電体Ａ２で被膜されている。
導体電極は被測定液と電気的に接続するためのあらゆる
形状をとることができるが、いずれの形状においても被
測定液を電極とするために液と電気的に接続する導体構
造となっており、配線接続部Ｅを持つ。電極固定材料Ｃ
は電極Ａ，電極Ｂ間の電気的絶縁と、電極の機械的保持
およびタンク上部への取り付け用構造体となっている。
上述電極構造を説明するために、３種類の形状を例とし
て図で示す。ただしこれは本発明の電極形状を制限する
ものではない。本発明はその技術的範囲に属する全ての
実施形態を含むものとする。図１は誘電体被膜電極と導
体電極を平行配置した電極の斜視図である。図２は円筒
状の導体電極の中心位置に誘電体被膜電極を配置した電
極の斜視図である。図３は図２で示した形状の断面図で
ある。図４はタンクを金属または導体で形成した場合の
斜視図である。図５は図４で示した形状の断面図であ
る。In the structure of the electrode according to claim 1, 2 or 3, the dielectric coated electrode A is coated with the dielectric A2 on the surface of the central conductor A1 except for the wiring connection portion D above.
The conductor electrode can have any shape for electrically connecting to the liquid to be measured, but in any shape, it has a conductor structure that electrically connects to the liquid so that the liquid to be measured becomes an electrode. , Has a wiring connection portion E. Electrode fixing material C
Is a structure for electrical insulation between the electrodes A and B, mechanical holding of the electrodes, and attachment to the upper part of the tank.
In order to explain the above-mentioned electrode structure, three types of shapes are shown in the figure as an example. However, this does not limit the electrode shape of the present invention. The present invention is intended to include all embodiments within its technical scope. FIG. 1 is a perspective view of an electrode in which a dielectric coating electrode and a conductor electrode are arranged in parallel. FIG. 2 is a perspective view of an electrode in which a dielectric coating electrode is arranged at the center of a cylindrical conductor electrode. FIG. 3 is a sectional view of the shape shown in FIG. FIG. 4 is a perspective view when the tank is made of metal or conductor. FIG. 5 is a sectional view of the shape shown in FIG.
【００１２】請求項１又は２又は３に記載する電極の静
電容量は Ｃ＝ε０・εｒ・Ｓ／ｄで表される。ただし
ε０＝真空の誘電率、εｒ＝誘電体被膜の比誘電率、Ｓ
＝電極面積、ｄ＝誘電体被膜の膜厚であるから、一定材
質の被膜であれば液の浸漬により電極面積のみが変化す
る。一方、液面より上部の静電容量はεｒ＝空気の比誘
電率、ｄ＝導体間の距離となり、液面下の静電容量に比
べて非常に小さい値となるため無視することができる。The capacitance of the electrode according to claim 1 or 2 or 3 is represented by C = ε0εrS / d. Where ε0 = vacuum permittivity, εr = relative permittivity of the dielectric film, S
= Electrode area, d = film thickness of the dielectric coating, so that if the coating is made of a constant material, only the electrode area changes by immersion of the liquid. On the other hand, the electrostatic capacitance above the liquid level is εr = relative permittivity of air and d = distance between conductors, which is a very small value compared with the electrostatic capacitance below the liquid level and can be ignored.
【００１３】以下、請求項１又は２又は３に記載する電
極を使用して液面レベル検出器とする場合の回路を一例
として説明する。ただし本回路は請求項１に記載する電
極の実施の形態を説明するために例示的に記載したもの
であり、本発明の技術的範囲を限定するものではない。
本発明はその技術的範囲に属する全ての実施形態を含む
ものとする。Hereinafter, a circuit in the case of using an electrode according to claim 1, 2 or 3 as a liquid level detector will be described as an example. However, this circuit is described as an example for explaining the embodiment of the electrode described in claim 1, and does not limit the technical scope of the present invention.
The present invention is intended to include all embodiments within its technical scope.
【００１４】図６は本発明の電極を使用して液面レベル
検出器１を構成した回路図である。図７は本回路が動作
するときの各部のタイミング波形である。ＣＳは請求項
１に記載する電極であり、０００６および００１０で上
述するごとく液の浸漬に応じて静電容量が変化する。発
振回路２はオペアンプＯＰ１、抵抗Ｒ１，Ｒ２，Ｒ３及
びＣＳで構成され、ＣＳの静電容量およびＲ１を発振時
定数とするＣＲ発振回路である。この発振回路２の発振
周波数はＲ２＝Ｒ３とすることにより概略１／（２．２
・ＣＳの静電容量・Ｒ１）となる。液の浸漬レベルが低
いときは、静電容量が少ないため高い周波数で発振し、
液の浸漬レベルが高い時は発振周波数が低くなる。すな
わち、液の浸漬レベルと発振周波数は反比例する。発振
回路２の出力発振周期Ｔにおけるハイレベル期間ＴＨと
ローレベル期間ＴＬの比は発振周波数が変化しても一定
であるため、ローレベル期間ＴＬのみの情報でも発信周
期情報とすることができる。FIG. 6 is a circuit diagram of a liquid level detector 1 using the electrodes of the present invention. FIG. 7 is a timing waveform of each part when this circuit operates. CS is the electrode according to the first aspect of the invention, and its capacitance changes depending on the immersion of the liquid as described above in 0006 and 0010. The oscillating circuit 2 is a CR oscillating circuit which includes an operational amplifier OP1, resistors R1, R2, R3 and CS, and which has an electrostatic capacitance of CS and R1 as an oscillation time constant. The oscillation frequency of the oscillation circuit 2 is approximately 1 / (2.2
・ The capacitance of CS is R1). When the immersion level of the liquid is low, it oscillates at a high frequency because the capacitance is low
When the immersion level of the liquid is high, the oscillation frequency becomes low. That is, the liquid immersion level and the oscillation frequency are inversely proportional. Since the ratio of the high level period TH and the low level period TL in the output oscillation cycle T of the oscillator circuit 2 is constant even if the oscillation frequency changes, information of only the low level period TL can be used as the transmission cycle information.
【００１５】積分回路３はオペアンプＯＰ２、Ｒ４，Ｃ
１およびＳ１で構成され、Ｓ１は発振回路２の出力周期
Ｔにおけるハイレベル期間ＴＨだけＣ１をリセットする
スイッチである。これにより発振回路１の出力周期Ｔに
おけるローレベル期間ＴＬのみ、Ｒ２を通じてＣ１が充
電される回路である。積分回路３の出力電圧ＴＷ２は積
分期間中直線的に除々に高くなり、そのピーク値ＰＶは
ローレベル期間ＴＬの幅に比例するため、周波数が高い
ときはピーク電圧が低くなり、周波数が低くなるとピー
ク電圧は高くなる。すなわち、発振周波数とピーク電圧
は反比例する。The integrating circuit 3 includes operational amplifiers OP2, R4 and C.
1 and S1, S1 is a switch that resets C1 only during the high level period TH in the output cycle T of the oscillation circuit 2. As a result, C1 is charged through R2 only during the low level period TL in the output cycle T of the oscillation circuit 1. The output voltage TW2 of the integrating circuit 3 gradually increases linearly during the integration period, and its peak value PV is proportional to the width of the low level period TL. Therefore, when the frequency is high, the peak voltage is low and when the frequency is low. The peak voltage will be higher. That is, the oscillation frequency and the peak voltage are inversely proportional.
【００１６】上述の積分回路３の出力電圧ＴＷ２は鋸歯
状波形であるため、そのままではアナログ指示量となら
ないので、そのピーク値を出力電圧として取り出すため
のピーク値保持回路４がＤ１，Ｃ２，Ｒ５で構成されて
いる。積分回路３の出力電圧ＴＷ２はダイオードＤ１を
通じてコンデンサＣ２をピーク電圧まで充電し、積分回
路３の出力電圧がリセットにより０Ｖまで下がってもダ
イオードＤ２により逆流阻止されるためＣ２の電圧はピ
ーク値を維持する。ただしこのままでは液レベルが低下
してピーク値が下がったとき追従できないので、高抵抗
Ｒ５を付加して微少電流を放電することにより、ピーク
値の変化に追従させる。これによりピーク電圧はその値
を保持した直流電圧ＴＷ３に変換される。Since the output voltage TW2 of the integrating circuit 3 described above has a sawtooth waveform, it does not become an analog instruction amount as it is. Therefore, the peak value holding circuit 4 for extracting the peak value as an output voltage is D1, C2, R5. It is composed of. The output voltage TW2 of the integrating circuit 3 charges the capacitor C2 to the peak voltage through the diode D1, and even if the output voltage of the integrating circuit 3 drops to 0V due to the reset, the diode D2 blocks the reverse current and the voltage of C2 maintains the peak value. To do. However, as it is, it is not possible to follow when the liquid level is lowered and the peak value is lowered. Therefore, by adding a high resistance R5 and discharging a minute current, the change in the peak value is followed. As a result, the peak voltage is converted into the DC voltage TW3 that holds the value.
【００１７】液の浸漬レベルと発振周波数は反比例し、
さらに発振周波数と出力電圧が反比例するため、液の浸
漬レベルと出力電圧Ｖが比例することとなる。The liquid immersion level and the oscillation frequency are inversely proportional,
Furthermore, since the oscillation frequency is inversely proportional to the output voltage, the liquid immersion level is proportional to the output voltage V.
【００１８】[0018]
【発明の効果】以上説明したように、本発明の静電容量
式電極は、簡単な構造を持ち、簡単な回路で液面レベル
検出器を構成できるため、従来の液面レベル検出器に比
較して低価格で製造できる上、小型省スペースである。As described above, the capacitance type electrode of the present invention has a simple structure, and since the liquid level detector can be configured with a simple circuit, it is compared with the conventional liquid level detector. It can be manufactured at low cost and is compact and space-saving.
【００１９】さらに、タンクの深さや測定範囲に合わせ
て自由な寸法で製造することができるため、使用範囲お
よび応用範囲を広げることができる。Further, since the tank can be manufactured with free dimensions according to the depth of the tank and the measuring range, the range of use and application can be expanded.
【００２０】[0020]
【図１】本発明の液面レベル検出器用電極で、誘電体被
膜電極と導体電極を平行配置した電極の斜視図である。FIG. 1 is a perspective view of an electrode for a liquid level detector of the present invention, in which a dielectric coating electrode and a conductor electrode are arranged in parallel.
【図２】本発明の液面レベル検出器用電極で、導体電極
を円筒形状構造とした電極の斜視図である。FIG. 2 is a perspective view of an electrode for a liquid level detector of the present invention, in which a conductor electrode has a cylindrical structure.
【図３】本発明の液面レベル検出器用電極で、導体電極
を円筒形状構造とした電極の断面図である。FIG. 3 is a cross-sectional view of an electrode for a liquid level detector of the present invention, in which the conductor electrode has a cylindrical structure.
【図４】本発明の液面レベル検出器用電極で、タンクを
金属または導体とした電極の斜視図である。FIG. 4 is a perspective view of an electrode for a liquid level detector of the present invention, in which the tank is made of metal or conductor.
【図５】本発明の液面レベル検出器用電極で、タンクを
金属または導体とした電極の断面図である。FIG. 5 is a cross-sectional view of an electrode for a liquid level detector of the present invention, in which the tank is made of metal or conductor.
【図６】本発明の液面レベル検出器用電極を使用した回
路図である。FIG. 6 is a circuit diagram using an electrode for a liquid level detector of the present invention.
【図７】図６で示した回路を動作させたときのタイミン
グ波形である。7 is a timing waveform when the circuit shown in FIG. 6 is operated.
Ａ 誘電体被膜電極 Ｂ 導体電極 Ｃ 電極固定材料 １ 液面レベル検出器 ２ 発信回路 ３ 積分回路 ４ ピーク値保持回路 ＣＳ 静電容量式電極 ＴＷ１ 発振回路２の出力波形 ＴＷ２ 積分回路３の出力波形 ＴＷ３ ピーク値保持回路４の出力波形 A Dielectric film electrode B conductor electrode C electrode fixing material 1 Liquid level detector 2 oscillator circuit 3 integrating circuit 4 Peak value holding circuit CS capacitance type electrode Output waveform of TW1 oscillator circuit 2 TW2 Output waveform of integrating circuit 3 TW3 Output waveform of peak value holding circuit 4
Claims (3)
て検出する液面レベル検出器のための電極で、誘電体被
膜電極は上部配線接続部を除いて棒状導体に誘電体を被
膜してあり、対応する他方の電極は被測定液を電極とす
るために上述の誘電体被膜電極と空間をおいて配置し
た、液と電気的に接続する導体となっていることを特徴
とする静電容量式液面レベル検出器用の電極。1. An electrode for a liquid level detector for detecting a change in liquid level by a change in capacitance, wherein the dielectric coating electrode has a rod-shaped conductor coated with a dielectric except for an upper wiring connecting portion. The corresponding other electrode is a conductor electrically connected to the liquid, which is arranged at a space from the above-mentioned dielectric coating electrode for using the liquid to be measured as an electrode. Electrode for capacitance type liquid level detector.
電極において、棒状導体に被膜する誘電体を高分子系樹
脂としたことを特徴とする液面レベル検出器用の電極。2. The electrode for a liquid level detector according to claim 1, wherein the dielectric material coated on the rod-shaped conductor is a polymer resin.
器用の電極において、棒状導体に被膜する誘電体をフッ
素樹脂としたことを特徴とする液面レベル検出器用の電
極。3. An electrode for a liquid level detector according to claim 1 or 2, wherein the rod-shaped conductor is coated with a fluorine resin as a dielectric material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001249749A JP2003057093A (en) | 2001-08-21 | 2001-08-21 | Electrode for liquid level detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001249749A JP2003057093A (en) | 2001-08-21 | 2001-08-21 | Electrode for liquid level detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003057093A true JP2003057093A (en) | 2003-02-26 |
Family
ID=19078706
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001249749A Pending JP2003057093A (en) | 2001-08-21 | 2001-08-21 | Electrode for liquid level detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2003057093A (en) |
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| JP2006038830A (en) * | 2004-06-24 | 2006-02-09 | Ngk Spark Plug Co Ltd | Capacitance type liquid state detecting sensor |
| JP2006153840A (en) * | 2004-10-29 | 2006-06-15 | Ngk Spark Plug Co Ltd | Liquid state detecting sensor |
| JP2007271593A (en) * | 2006-03-08 | 2007-10-18 | Miura Co Ltd | Electrode rod for detecting water level of once-through boiler, method of detecting water level of once-through boiler and method of controlling water level of once-through boiler |
| US7337662B2 (en) | 2004-06-24 | 2008-03-04 | Ngk Spark Plug Co., Ltd. | Electrostatic capacity type liquid state detecting sensor |
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| JP2010121950A (en) * | 2008-11-17 | 2010-06-03 | Loarant Corp | Device of measuring amount of liquid |
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| US7337662B2 (en) | 2004-06-24 | 2008-03-04 | Ngk Spark Plug Co., Ltd. | Electrostatic capacity type liquid state detecting sensor |
| JP2006038830A (en) * | 2004-06-24 | 2006-02-09 | Ngk Spark Plug Co Ltd | Capacitance type liquid state detecting sensor |
| JP4559293B2 (en) * | 2004-10-29 | 2010-10-06 | 日本特殊陶業株式会社 | Liquid state detection sensor |
| JP2006153840A (en) * | 2004-10-29 | 2006-06-15 | Ngk Spark Plug Co Ltd | Liquid state detecting sensor |
| US8122764B2 (en) | 2004-10-29 | 2012-02-28 | Ngk Spark Plug Co., Ltd. | Liquid state detecting sensor |
| JP2007271593A (en) * | 2006-03-08 | 2007-10-18 | Miura Co Ltd | Electrode rod for detecting water level of once-through boiler, method of detecting water level of once-through boiler and method of controlling water level of once-through boiler |
| KR101329371B1 (en) | 2006-03-08 | 2013-11-14 | 미우라고교 가부시키카이샤 | Electrode rod for detecting water-level, method of detecting water-level, method of controlling water-level in a boiler, and method of controlling water-level in a steam separator |
| JP2010121962A (en) * | 2008-11-17 | 2010-06-03 | Loarant Corp | Device of measuring amount of liquid |
| JP2010121950A (en) * | 2008-11-17 | 2010-06-03 | Loarant Corp | Device of measuring amount of liquid |
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| US11326924B2 (en) | 2019-03-29 | 2022-05-10 | Korea Institute Of Civil Engineering And Building Technology | Device for measuring water level by using capacitive technique, and method therefor |
| CN113029071A (en) * | 2021-01-28 | 2021-06-25 | 云南国钛金属股份有限公司 | Device and method for accurately measuring thickness and liquid level of magnesium in magnesium electrolytic cell |
| CN113029071B (en) * | 2021-01-28 | 2022-11-18 | 云南国钛金属股份有限公司 | Device and method for accurately measuring thickness and liquid level of magnesium in magnesium electrolytic cell |
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