JPS58106423A - Liquid level measuring device - Google Patents
Liquid level measuring deviceInfo
- Publication number
- JPS58106423A JPS58106423A JP56205987A JP20598781A JPS58106423A JP S58106423 A JPS58106423 A JP S58106423A JP 56205987 A JP56205987 A JP 56205987A JP 20598781 A JP20598781 A JP 20598781A JP S58106423 A JPS58106423 A JP S58106423A
- Authority
- JP
- Japan
- Prior art keywords
- liquid level
- transmission line
- capacitance
- capacity
- measured
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
- G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
- G01F23/266—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors measuring circuits therefor
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は貯液タンクに挿入された液面センサにより液面
高さに比例した静電容量を測定し、この被測静電容ｌか
ら貯液タンク内の液面高さを演算するようにした液面測
定装置に関する。Detailed Description of the Invention The present invention measures capacitance proportional to the liquid level height using a liquid level sensor inserted into a liquid storage tank, and calculates the liquid level height in the liquid storage tank from this measured electrostatic capacitance l. The present invention relates to a liquid level measuring device that calculates the amount of liquid.
従来、静電容量式液面計は種々のものが知られているが
、最も一般的なものは同軸円筒型のセンサを使用し、被
測液体の液面高さに比例して内外筒間の比舖電率が変化
することを利用した方式である。そして被測静電容量の
測定はブリツノ回路やＬＣ型発振回路を用い、発振周波
数から間接的に行ない、表示計器で液面表示を行なって
いる。Various types of capacitive liquid level gauges have been known, but the most common type uses a coaxial cylindrical sensor and adjusts the distance between the inner and outer cylinders in proportion to the liquid level height of the liquid to be measured. This method takes advantage of the fact that the relative electrical constant of The capacitance to be measured is measured indirectly based on the oscillation frequency using a Blitzno circuit or an LC type oscillation circuit, and the liquid level is displayed using a display instrument.
ここで、液面センサと発振回路を含む演算回路本体とが
数１０ｍも離間している場合には、該液面センナと演算
回路との間の伝送線に生じる浮遊容量を無視できない。Here, if the liquid level sensor and the main body of the arithmetic circuit including the oscillation circuit are separated by several tens of meters, the stray capacitance generated in the transmission line between the liquid level sensor and the arithmetic circuit cannot be ignored.
この浮遊容量が温度条件に影響されると共に、液面セン
サを含む共掘回路各部が周囲温度、湿度等の外界条件に
より影響され、計測精度を低下させることににみ、本出
願人は先に特願昭５２−３５５７９号（特開昭５３−１
３１０６８号）として、貯液タンク近傍に容−１補正用
コンデンサを設け、液面センサを第１の伝送線を介して
第１の発振回路と接続し、また容量補正用コンデンサを
第２の伝送線を介して第２の発振回路に接続し、該第１
．第２の発振回路からの発振周波数の差を演算すること
により、液面センサが受ける外界条件を容量補正用コン
デンサで補償し、かつ第１．第２の伝送線を同一構造の
ものとするととにより浮遊容量を見掛は上演算ファクタ
から除去することができる構成のものを提案した。Recognizing that this stray capacitance is affected by temperature conditions, and that various parts of the co-mining circuit including the liquid level sensor are affected by external conditions such as ambient temperature and humidity, reducing measurement accuracy, the applicant first Patent Application No. 52-35579 (Japanese Unexamined Patent Application No. 53-1
31068), a capacity-1 correction capacitor is provided near the liquid storage tank, the liquid level sensor is connected to the first oscillation circuit via the first transmission line, and the capacity correction capacitor is connected to the second transmission line. connected to a second oscillation circuit via a line, and the first
．． By calculating the difference in the oscillation frequency from the second oscillation circuit, the external conditions that the liquid level sensor receives are compensated by the capacitance correction capacitor, and the first oscillation circuit compensates for the external conditions that the liquid level sensor receives. We have proposed a configuration in which the stray capacitance can apparently be removed from the calculation factor by making the second transmission line have the same structure.
しかし、前述した先願に係るものは、第１．第２の発振
周波数の中に第１．第２の伝送線途中の浮遊容量の成分
が含まれているため、各浮遊容量が全く同一でない場合
には液面信号にその影響が誤差として生じてしまう欠点
があった。また、工事に際しては伝送線の短縮、延長は
行なわないと、耐
と全原則としていたが、このような制限は工事を時とし
て困難とする欠点がめった。さらに、第１゜第２の伝送
線を同一長さに接続しても、・・ンダの盛付は状態、ね
じの締付は状態によって浮遊容量が異なってしまう欠点
があった。However, the one related to the earlier application mentioned above is No. 1. The first oscillation frequency is within the second oscillation frequency. Since a component of stray capacitance in the middle of the second transmission line is included, there is a drawback that if the stray capacitances are not exactly the same, the influence of the stray capacitance will cause an error in the liquid level signal. Furthermore, during construction, the general rule was that transmission lines should not be shortened or extended, but such restrictions often had the drawback of making construction difficult at times. Furthermore, even if the first and second transmission lines are connected to the same length, there is a drawback that the stray capacitance varies depending on the condition of the arrangement of the conductor and the condition of the tightening of the screw.
本発明は前述した従来技術による欠点を改良したもので
、その特徴とするところは液面センサが挿入された貯液
タンク近傍に標準コンデンサを設け、被測静電容量、伝
送線途中の浮遊容量、標準コンデンサの標準容量を含ん
で発振回路を構成し、前記貯液タンク近傍には前記各容
量を発掘回路に選択切換可能な切換スイッチを設けるこ
とにより伝送線を１本のみとすることができ、かつ伝送
線の浮遊容量に伴なう発振周波数を独立に演算ファクタ
とすることができ、もって計測精度を向上させるように
した液面測定装置を提供するものである。The present invention improves the drawbacks of the prior art as described above, and is characterized by providing a standard capacitor near the liquid storage tank in which the liquid level sensor is inserted, and measuring the capacitance to be measured and the stray capacitance in the middle of the transmission line. , an oscillation circuit is configured including the standard capacitance of a standard capacitor, and a changeover switch is provided near the liquid storage tank that can selectively switch each capacitance to the excavation circuit, thereby reducing the number of transmission lines to only one. The present invention provides a liquid level measuring device in which the oscillation frequency associated with the stray capacitance of the transmission line can be independently used as a calculation factor, thereby improving measurement accuracy.
以下、本発明について図面に示す実施例と共に説明する
。The present invention will be described below along with embodiments shown in the drawings.
第１図および第２図は本発明の第１の実施例を示し、貯
液タンク１には液面センサ２が挿入されている。液面セ
／す２は例えば４屯性材料からなる同軸円筒型センサが
用いられ、被測液体の誘電率と液体以外の誘電率の差に
より液面に比例しだ被測靜電容ｆｔｃｘを検出するもの
である。３は貯液タンク１の近傍に設けられた標準コン
デンサで、該コンデンサ３の標準容ｔ Ｃ＋は適宜の値
、例えば被測静電容量ＣＸの変化範囲のほぼ中間の値が
選定され、しかも液面センサ１が受ける温度、温度等の
外界条件と等しくなるような位置に設置されるＯ
前記貯液タンク１近傍にはドライバ４によって駆動され
る切換スイッチ５が設けられ、該切換スイッチ５は第２
図に示す如く切換位置５０．５１゜５２と、切換接点５
３とから構成され、ドライバ４を駆動することにより切
換接点５３を所定の周期で作動し、切換位置５０，５１
．５２を選択するように構成されている。そして、切換
スイッチ５は伝送線６を介して事務室等の安全場所に設
けられたインダクタンスＬのコイル７と接続されている
。1 and 2 show a first embodiment of the present invention, in which a liquid level sensor 2 is inserted into a liquid storage tank 1. FIG. For the liquid level cell 2, a coaxial cylindrical sensor made of, for example, a 4-layer material is used, and the measured static capacitance ftcx is detected in proportion to the liquid level based on the difference between the dielectric constant of the liquid to be measured and the dielectric constant of other liquids. It is something to do. Reference numeral 3 denotes a standard capacitor installed near the liquid storage tank 1, and the standard capacitance tC+ of the capacitor 3 is selected to be an appropriate value, for example, a value approximately in the middle of the variation range of the capacitance to be measured CX, and A changeover switch 5 driven by a driver 4 is provided near the liquid storage tank 1, and the changeover switch 5 2
As shown in the figure, the switching position 50.51°52 and the switching contact 5
3, and by driving the driver 4, the switching contact 53 is actuated at a predetermined cycle, and the switching position 50, 51 is
．． 52 is selected. The changeover switch 5 is connected via a transmission line 6 to a coil 7 with an inductance L provided in a safe place such as an office.
次に８は本発明に用いる発振回路で、該発掘回路８は第
１図に示すように液面センサ２、標準コ（５）
ンデンサ３、切換スイッチ５、伝送線６、コイル７等か
らなる。そして、いま伝送線６途中の分布容量、切換ス
イッチ５、コイル７等に存在する全浮遊容ｉ１９をＣｏ
とすると、第２図に示す如く切換接点５３を切換位置５
０としたときには浮遊容量ｃｏとコイル７とだけが直列
接続され、切換接点５３を切換位置５１としたときには
標準コンデンサ３の標準容量Ｃ，と浮遊容ｐ４′ｃｏと
が並列接続され、さらに切換接点５３を切換位置５２と
したときには液面センサ２の被測静電容量ＣＸと浮遊容
量ｃ。Next, reference numeral 8 denotes an oscillation circuit used in the present invention, and as shown in FIG. . Now, the distributed capacitance in the middle of the transmission line 6, the total floating capacitance i19 existing in the changeover switch 5, the coil 7, etc. is Co
Then, as shown in FIG. 2, the switching contact 53 is moved to the switching position 5.
When set to 0, only the stray capacitance co and the coil 7 are connected in series, and when the switching contact 53 is set to the switching position 51, the standard capacitance C of the standard capacitor 3 and the stray capacitance p4'co are connected in parallel, and the switching contact 53 is the switching position 52, the capacitance to be measured CX and the stray capacitance c of the liquid level sensor 2.
とが並列接続されるような回路構成となっている。The circuit configuration is such that the two are connected in parallel.
ここで、前記発振回路８はコイル７と各容量ＣＯ＋ＣＩ
ＩＣＸ等との共感回路を含む発振回路を構成し、切換ス
イッチ５の切換接点５３を切換位置５０゜５１．５２に
切換えたとき発振周波数ｆ。ｌ ｆ 、 ｌ ｆｘなる
高周波を発振する。Here, the oscillation circuit 8 includes a coil 7 and each capacitance CO+CI.
An oscillation circuit including a sympathetic circuit with ICX etc. is constructed, and when the switching contact 53 of the changeover switch 5 is switched to the switching position 50°51.52, the oscillation frequency f. It oscillates high frequencies l f and l fx.
さらに、発振回路８の次段には周波数カウンタ１０が容
量結合、抵抗結合等の結合回路（図示せず）を介して接
続され、該周波数カウンタ１０は発振回路８からの発振
周波数ｆ。Ｔ ｆ １＋ ｆｘを順次（６）
計数測定し、インタフェース回路１１、パスライン１２
を介して中央処理装置１３に入力する。１４は液面表示
器、１５はドライバ４を駆動するだめの信号を出力する
信号線を示し、これら液面表示器１４、信号線１５はイ
ンタフェース回路１１、パスライン１２を介して中央処
理装置１３と接続されている。そして、周波数カウンタ
１０によって測定された周波数から、中央処理装置１３
で後述する演算を行ない、表示器１４に貯液タンク１内
液面の表示を行なう。従って、本実施例においては周波
数カウンタ１０、中央処理装置１３等から演算回路１６
が構成される。Furthermore, a frequency counter 10 is connected to the next stage of the oscillation circuit 8 via a coupling circuit (not shown) such as a capacitive coupling or a resistive coupling. Sequentially count and measure T f 1 + fx (6) and connect the interface circuit 11 and the pass line 12.
The data is input to the central processing unit 13 via the . Reference numeral 14 indicates a liquid level indicator, and 15 indicates a signal line for outputting a signal for driving the driver 4.These liquid level indicator 14 and signal line 15 are connected to the central processing unit 13 via an interface circuit 11 and a pass line 12. is connected to. Then, from the frequency measured by the frequency counter 10, the central processing unit 13
The calculations described later are performed, and the liquid level in the liquid storage tank 1 is displayed on the display 14. Therefore, in this embodiment, the frequency counter 10, central processing unit 13, etc.
is configured.
本実施例は以上のように構成されるが、次にその作動原
理について説明する。Although the present embodiment is constructed as described above, the principle of operation thereof will be explained next.
まず、発振回路８の発振周波数は、切換スイッチ５の切
換接点５３を切換位置５０ 、５１ 、５２としたとき
の周波数ｆ。＋ ｆ ｌ＋ ｆｘは次、のようになる。First, the oscillation frequency of the oscillation circuit 8 is the frequency f when the changeover contact 53 of the changeover switch 5 is set to the changeover positions 50, 51, and 52. + f l + fx is as follows.
（１，１、（２）式からｃｏを求めると、同様に（１）
、 （３）式から
Ｃｏ ＝ Ｃｘ ’ （、ｆｏ／、ｆｚ）２−１
°−（５）となる。そして、（４） 、 （５）式から
を求めることができる。(1, 1, If co is calculated from equations (2), similarly (1)
, From formula (3), Co = Cx' (,fo/,fz)2-1
°−(5). Then, it can be obtained from equations (4) and (5).
従って、所定の被測液体、例えばガソリン、水等に液面
センサ２を浸漬したとき、該液面センサ２の単位長さ当
りの静電容ｆｉｔｃｕと、貯液タンク１内に被測液体が
存在せず、液面が零のときの残留静電容量Ｂとが既知で
あれば、液面Ｈはｕ
として演算することができる。Therefore, when the liquid level sensor 2 is immersed in a predetermined liquid to be measured, such as gasoline or water, the electrostatic capacitance fitcu per unit length of the liquid level sensor 2 and the presence of the liquid to be measured in the liquid storage tank 1 are determined. If the residual capacitance B when the liquid level is zero is known, the liquid level H can be calculated as u.
以上の点から、液面測定を行なうときにはドライバ４を
所定間隔で駆動し、発振回路８によって発振周波数ｆ
＝ｆｔ、ｆ の高周波を発振させ、液面を間接的に演
算するため、演算回路１６を構成する周波数カウンタ１
０と中央処理装置１３とを用い、周波数カウンタ１０に
よって発振回路８からの周波数ｆ。＊ｆｓ＊ｆｚを順次
測定し、この測定結果を中央処理装置１３によって（７
）式の演算をすれば、液面高さＨを液面表示計１５に表
示させることができる。From the above points, when measuring the liquid level, the driver 4 is driven at predetermined intervals, and the oscillation frequency f is set by the oscillation circuit 8.
In order to indirectly calculate the liquid level by oscillating a high frequency wave of =ft, f, a frequency counter 1 forming the calculation circuit 16 is used.
0 and the central processing unit 13, the frequency f from the oscillation circuit 8 is detected by the frequency counter 10. *fs*fz is measured sequentially, and the measurement results are processed by the central processing unit 13 (7
), the liquid level height H can be displayed on the liquid level indicator 15.
このように、本発明によれば、伝送線６を１本とし、切
換スイッチ５によシ液面センサ２と標準コンデンサ３と
を選択的に接続する構成としているから、従来技術のよ
うに２本の伝送線を用いるものと比較して伝送線に起因
する誤差を生じると（９）
とかない。また、伝送線６途中の分布容量、切換スイッ
チ５、コイル７等の浮遊容量等の合計浮遊容’ｉ：ｃｏ
を独立の演算ファクタに入れることができ、しかもこれ
に基づく周波数ｆ０を（６）式のＣＸにおける分母、分
子に持つことができるから、浮遊容量ｃｏの影響を相殺
し、高精度な計測結果を得ることができる。As described above, according to the present invention, there is only one transmission line 6, and the liquid level sensor 2 and the standard capacitor 3 are selectively connected by the changeover switch 5. Compared to the case where a real transmission line is used, there are no errors caused by the transmission line (9). In addition, the total stray capacitance 'i:co
can be put into an independent calculation factor, and the frequency f0 based on this can be included in the denominator and numerator of CX in equation (6), so the influence of the stray capacitance co can be canceled out and highly accurate measurement results can be obtained. Obtainable.
次に、第３図は本発明の第２の実施例を示す。Next, FIG. 3 shows a second embodiment of the present invention.
本実施例は貯液タンクをＮ基有する場合の液面測定装置
にして、前述した第１の実施例と同一構成要素には同一
符号を付すものとする。This embodiment is a liquid level measuring device having N liquid storage tanks, and the same components as in the above-described first embodiment are given the same reference numerals.
図中、ＩＡ、ＩＢ・・・ＩＮは貯液タンク、２Ａ。In the figure, IA, IB...IN are liquid storage tanks, 2A.
２Ｂ、・・・２Ｎは液面センサ、３Ａ、３Ｂ 、・・・
３Ｎは標準コンデンサ、４Ａ、４Ｂ、・・・４Ｎはドラ
イバ、５Ａ、５Ｂ、・・・５Ｎは切換スイッチ、６Ａ。2B,...2N are liquid level sensors, 3A, 3B,...
3N is a standard capacitor, 4A, 4B, . . . 4N is a driver, 5A, 5B, . . . 5N is a changeover switch, 6A.
６Ｂ、・・・６Ｎは伝送線、１４Ａ、１４Ｂ、・・・１
４Ｎは液面表示計を示すものとする。２１はインタフェ
ース回路１１を介して中央処理装置１１３がらの信号に
より作動するドライバで、２２．２３は該ドライバ２１
によって同時に駆動される伝送線選（１０）
択スイッチ、センサ選択スイッチをそれぞれ示す。6B,...6N are transmission lines, 14A, 14B,...1
4N indicates the liquid level indicator. 21 is a driver operated by a signal from the central processing unit 113 via the interface circuit 11; 22 and 23 are the drivers 21;
A transmission line selection switch (10) and a sensor selection switch are shown, respectively, which are simultaneously driven by the transmission line selection switch (10).
ここで、伝送線選択スイッチ２２には各伝送線６Ａ、６
Ｂ、・・・６Ｎが接続されると共に単一のコイル７が接
続され、一方、センサ選択スイッチ２２はインタフェー
ス回路１１に連なる信号線２４が接続されると共に各ド
ライバ４Ａ、４Ｂ。Here, the transmission line selection switch 22 includes each transmission line 6A, 6
B, . . . 6N are connected to each other, and a single coil 7 is connected thereto, while the sensor selection switch 22 is connected to a signal line 24 connected to the interface circuit 11, and is connected to each driver 4A, 4B.
・・・４Ｎに連なる信号線２５Ａ、２５Ｂ、・・・２５
Ｎが接続されている。また、２６は貯液タンクの数だけ
の入力スイッチｒ Ａ、 Ｊ 、 ｒ Ｂ Ｊ 、・・
・ｒＮＪおよびｒＡＬＪを有するタンク指定スイッチで
、該タンク指定スイッチ２６のスイッチｒＡＪを操作す
ることによって、ドライバ２１が作動し、猷送線選択ス
イッチ２２が伝送線６Ａをコイル７と凄続し、同時にセ
ンサ選択スイッチ２３がｒライパ４Ａと接続し、第１の
実施例と同様にドライバ４Ａが所定周期で切換スイッチ
５Ａの切換接点（５３Ａ）を各切換位置（５０Ａ 、？
、１ 、（５１Ａ）。...Signal lines 25A, 25B, ...25 connected to 4N
N is connected. In addition, 26 indicates input switches r A, J, r B J, . . . corresponding to the number of liquid storage tanks.
- By operating the switch rAJ of the tank designation switch 26 in the tank designation switch having rNJ and rALJ, the driver 21 is activated, and the transmission line selection switch 22 connects the transmission line 6A to the coil 7, and at the same time The sensor selection switch 23 is connected to the r-liper 4A, and the driver 4A moves the changeover contact (53A) of the changeover switch 5A to each changeover position (50A, ?) at a predetermined period as in the first embodiment.
, 1 , (51A).
（５２Ａ）に切換えるように作動する。同様に、タンク
指定スイッチ２６のスイッチｒＢＪを操作すると眠送線
選択スイッチ２２が伝送線６Ｂをコイル７と接続し、同
時にセンサ選択スイッチ２３がＰライパ４Ｂと接続する
。(52A). Similarly, when the switch rBJ of the tank designation switch 26 is operated, the sleep transmission line selection switch 22 connects the transmission line 6B to the coil 7, and at the same time, the sensor selection switch 23 connects it to the P-liper 4B.
本実施例はこのように構成されるから、所望の貯液タン
ク、例えばタンクＩＮ内の残着を検出するためタンク指
定スイッチ２６のスイッチｒＮＪを投入すると、ｒライ
パ２１によって伝送線選択スイッチ２２が伝送線６Ｎを
選択すると共にセンサ選択スイッチ２３がドライバ４Ｎ
を選択し、該ドライバ４Ｎが切換スイッチ５Ｎを所定周
期で作動する。この結果、発振回路８からは切換位置（
５ＯＮ）、（５１Ｎ）、（５２Ｎ）に対応して周波数ｆ
ｏ。Since the present embodiment is configured in this way, when the switch rNJ of the tank designation switch 26 is turned on to detect residue in a desired liquid storage tank, for example, tank IN, the transmission line selection switch 22 is turned on by the r writer 21. While selecting the transmission line 6N, the sensor selection switch 23 selects the driver 4N.
is selected, and the driver 4N operates the changeover switch 5N at a predetermined period. As a result, the oscillation circuit 8 detects the switching position (
5ON), (51N), (52N), the frequency f
o.
ｆｓ 、ｆｘを発振し、第１の実施例と同様に演算回路
１６が液面高さを演算し、液面表示計１４Ｎに測定結果
を表示する。なお、タンク指定スイッチ２６のうち、ス
イッチｒＡＬＪは全貯液タンクＩＡ、ＩＢ 、・・・Ｉ
Ｎについて順次一定時間毎に自動的に液面監視し、この
結果を各表示計１４Ａ。fs and fx are oscillated, and the calculation circuit 16 calculates the liquid level height as in the first embodiment, and displays the measurement result on the liquid level indicator 14N. Note that among the tank designation switches 26, the switch rALJ is for all liquid storage tanks IA, IB,...I.
The liquid level of N is automatically monitored at regular intervals, and the results are displayed on each display meter 14A.
１４Ｂ、・・・１４Ｎに表示させるためのスイッチであ
り、急激な液面変動のない場合にはスイッチｒ ＡＬ
Ｊ’！ｉ投入しておくだけで第４図のように計測結果を
順次表次させることができる。This is a switch for displaying on 14B, . . . 14N, and when there is no sudden change in the liquid level, switch r AL is used.
J'! By simply inserting the i, the measurement results can be displayed sequentially as shown in FIG.
さらに、貯液タンク１が横円筒型のタンクである場合に
は、当該タンクの液面高さと液量との関係を示すタンク
テーブルを利用して液量を演算しうる。即ち、液面をＸ
軸、液量をｙ軸とすると、タンクテーブル曲線はなだら
かなＳ字形となる。Furthermore, when the liquid storage tank 1 is a horizontal cylindrical tank, the liquid amount can be calculated using a tank table showing the relationship between the liquid level height and the liquid amount in the tank. In other words, the liquid level is
If the axis and liquid volume are taken as the y-axis, the tank table curve becomes a gentle S-shape.
そこで、液面の最大値を１、液量の最大値を１として、
前記タンクテーブル曲線をｎ個の線分ｙ ＝ ｘＡｎ
＋ Ｂｎ −（８）に分割し、ｎ個の
定数Ａｎ 、 Ｂｎを定める。一方、貯液タンク１の“
満タン”時の液面高さ、即ち直径をＤｈとすると、（７
）式から
Ｃｕ Ｘ Ｄｈ
を求めることができる。Therefore, assuming that the maximum value of the liquid level is 1 and the maximum value of the liquid volume is 1,
The tank table curve is divided into n line segments y = xAn
+ Bn - (8) and determine n constants An and Bn. On the other hand, “
If the liquid level height when the tank is full, that is, the diameter, is Dh, then (7
) Cu X Dh can be obtained from the equation.
そこで、Ａｎ 、 Ｂｎ 、自、 Ｂ 、 Ｃｕ 、
Ｄｈからなる定数を中央処理装置１３に記憶させ、（８
） 、 （９）式の演算を行なわせることによって液′
ｊｋｙを１満タン”（１３）
時の百分率（％）として求めることができる。また”満
タン時の液量Ｖから、残量液讐τをτ＝ｖｘｙ
・・・００として演算し、表示計１４に液
量表示させることができる。Therefore, An, Bn, self, B, Cu,
A constant consisting of Dh is stored in the central processing unit 13, and (8
), by performing the calculation of equation (9), the liquid ′
jky can be determined as a percentage (%) of 1 full tank (13). Also, from the liquid volume V when the tank is full, the remaining liquid τ can be calculated as τ=vxy
...00, and the liquid amount can be displayed on the display meter 14.
なお、本発明の実施例においては演算回路１６を中央処
理装置１３を含むマイクロコンピュータとして構成しう
るが、（６）または（７）式に従って演算を行なう画数
発生器を用いてもよいものである。In the embodiment of the present invention, the arithmetic circuit 16 can be configured as a microcomputer including the central processing unit 13, but a stroke number generator that performs arithmetic operations according to equation (6) or (7) may also be used. .
また被測静電容量ＣＩの損失が大きい場合、例えば被測
液体が水のような場合には損失も大きく、また比誘電率
も大きいので、被測靜電容１１ｃｘと直列に固定客ｉＣ
ｓを付加し、
として演算することによシ、被測靜電容ＪｉｌｔＣｘの
容量および損失を調整することができる。In addition, when the loss of the capacitance CI to be measured is large, for example, when the liquid to be measured is water, the loss is also large and the dielectric constant is also large.
By adding s and calculating as follows, the capacitance and loss of the static capacitance to be measured JiltCx can be adjusted.
本発明に係る液面測定装置は以上詳細に述べた（１４）
如くであって、１基のタンクに１本の伝送線で足りるか
ら、従来技術のように２本の伝送線を用いるものに比較
して伝送線に起因する計測誤差を完全に除去でき、また
浮遊容量の影響を相殺できるから測定精度を高めること
ができ、しかも多数基のタンク内液面を簡単な構成によ
って測定しうる等の効果を奏する。The liquid level measuring device according to the present invention is as described in detail above (14), and since one transmission line is sufficient for one tank, it is not necessary to use two transmission lines as in the prior art. In comparison, measurement errors caused by transmission lines can be completely eliminated, and the effects of stray capacitance can be canceled out, increasing measurement accuracy.Furthermore, liquid levels in multiple tanks can be measured with a simple configuration. It has the effect of
第１図および第２図は本発明の第１の実施例を示し、第
１図はその系統図、第２図は電気回路図、第３図および
第４図は本発明の第２の実施例を示す系統図、第４図は
自動液面監視の場合の作動順序を示す線図である。
１・・・貯液タンク、２・・・液面センサ、３・・・標
準コンデンサ、４・・・ｒライバ、５・・・切換スイッ
チ、６・・・伝送線、８・・・発振回路、９・・・浮遊
容量、１０・・・周波数カウンタ、１１・・・インタ、
フェース回路、１３・・・中央処理装置、１４・・・表
示器、１６・・・演算回路。
（１５）1 and 2 show a first embodiment of the present invention, FIG. 1 is a system diagram thereof, FIG. 2 is an electric circuit diagram, and FIGS. 3 and 4 are a second embodiment of the present invention. An exemplary system diagram, FIG. 4, is a diagram showing the operating sequence in the case of automatic liquid level monitoring. 1... Liquid storage tank, 2... Liquid level sensor, 3... Standard capacitor, 4... R driver, 5... Changeover switch, 6... Transmission line, 8... Oscillation circuit , 9... Stray capacitance, 10... Frequency counter, 11... Inter,
Face circuit, 13...Central processing unit, 14...Display device, 16...Arithmetic circuit. (15)
Claims (1)
検出する液面センサと、該液面センサの被測静電容量Ｃ
Ｘ、伝送線途中の分布容量を含めた浮遊界ｔｃｏ、前記
貯液タンク近傍に設けられた既知の標準容ｔ ｅ ｌを
含んで構成される発振回路と、まだ前記貯液タンク近傍
に設けられ、該発振回路と前記被測静電容量ＣＸ、浮遊
界ｔＣｏ、標準容量Ｃ１とを選択的に接続する切換スイ
ッチと、該切換スイッチを介して前記発振回路に被測静
電容量Ｃｘと浮遊容量Ｃ８、浮遊界１・Ｃ０のみ、標準
容量Ｃｉ と浮遊界’Ｉｔｃｏを接続したときの発振
周波数をそれぞれｆＸ、ｆｏ、ｆｌとすると、 全求め、前記貯液タンクの液面高さを演算する演算回路
とから構成してなる液面測定装置。[Claims] A liquid level sensor that detects a measured capacitance Cx proportional to the liquid level height in a liquid storage tank, and a measured capacitance C of the liquid level sensor.
X, a floating field tco including the distributed capacitance in the middle of the transmission line, an oscillation circuit configured to include a known standard volume t e l provided near the liquid storage tank, and a floating field tco including the distributed capacitance in the middle of the transmission line, and , a changeover switch that selectively connects the oscillation circuit to the capacitance to be measured CX, the floating field tCo, and the standard capacitance C1; C8, floating field 1/C0 only, if the oscillation frequencies when standard capacity Ci and floating field 'Itco are connected are fX, fo, and fl, respectively, calculate the total and calculate the liquid level height of the liquid storage tank. A liquid level measuring device consisting of a circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56205987A JPS58106423A (en) | 1981-12-18 | 1981-12-18 | Liquid level measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56205987A JPS58106423A (en) | 1981-12-18 | 1981-12-18 | Liquid level measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58106423A true JPS58106423A (en) | 1983-06-24 |
| JPH0413646B2 JPH0413646B2 (en) | 1992-03-10 |
Family
ID=16516016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56205987A Granted JPS58106423A (en) | 1981-12-18 | 1981-12-18 | Liquid level measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58106423A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016517016A (en) * | 2013-04-24 | 2016-06-09 | エスケイエフ ルーブリケイション システムズ ジャーマニー ゲゼルシャフト ミット ベシュレンクテル ハフツングＳＫＦ Ｌｕｂｒｉｃａｔｉｏｎ Ｓｙｓｔｅｍｓ Ｇｅｒｍａｎｙ ＧｍｂＨ | Filling level measuring device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5414266A (en) * | 1977-07-04 | 1979-02-02 | Tokico Ltd | Liquid level detector |
-
1981
- 1981-12-18 JP JP56205987A patent/JPS58106423A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5414266A (en) * | 1977-07-04 | 1979-02-02 | Tokico Ltd | Liquid level detector |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016517016A (en) * | 2013-04-24 | 2016-06-09 | エスケイエフ ルーブリケイション システムズ ジャーマニー ゲゼルシャフト ミット ベシュレンクテル ハフツングＳＫＦ Ｌｕｂｒｉｃａｔｉｏｎ Ｓｙｓｔｅｍｓ Ｇｅｒｍａｎｙ ＧｍｂＨ | Filling level measuring device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0413646B2 (en) | 1992-03-10 |
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