JPH01223316A - Electrostatic capacity type liquid level measuring apparatus - Google Patents
Electrostatic capacity type liquid level measuring apparatusInfo
- Publication number
- JPH01223316A JPH01223316A JP63049382A JP4938288A JPH01223316A JP H01223316 A JPH01223316 A JP H01223316A JP 63049382 A JP63049382 A JP 63049382A JP 4938288 A JP4938288 A JP 4938288A JP H01223316 A JPH01223316 A JP H01223316A
- Authority
- JP
- Japan
- Prior art keywords
- inner cylinder
- liquid level
- liquid
- cylinder
- dielectric constant
- 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
- 239000007788 liquid Substances 0.000 title claims abstract description 114
- 238000005259 measurement Methods 0.000 claims description 10
- 238000004364 calculation method Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 230000004323 axial length Effects 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は貯液タンク内の液面高さ、残量等（以下、「液
面」という）を測定するため、同軸円筒形の液面センサ
を用いた静電容量式液面測定装置に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a coaxial cylindrical liquid level to measure the liquid level height, remaining amount, etc. (hereinafter referred to as "liquid level") in a liquid storage tank. This invention relates to a capacitive liquid level measuring device using a sensor.
一般に、ガソリン給油所の地下タンク等にあっては、油
の残量を常時監視するために、液面測定装置が用いられ
ている。Generally, in underground tanks of gasoline filling stations, liquid level measuring devices are used to constantly monitor the remaining amount of oil.
従来、この種の液面測定装置は、それぞれ１本の金属製
筒体からなる外筒と内筒を同軸円筒状に形成してなる同
軸円筒形の液面センサを有し、該液面センサを貯液タン
ク内に挿入し、液面高さに応じて該液′面センサの外筒
と内筒との間に形成される電極間静電容量に基づいて液
面高さを測定するようになっている。Conventionally, this type of liquid level measuring device has a coaxial cylindrical liquid level sensor formed by coaxially cylindrical outer and inner cylinders each made of a single metal cylinder. is inserted into the liquid storage tank, and the liquid level height is measured based on the interelectrode capacitance formed between the outer cylinder and the inner cylinder of the liquid level sensor according to the liquid level height. It has become.
即ち、外筒、内筒の軸方向長さを見、液面高さをΔ交、
外筒の内径をｄｉ、内筒の外径をｄ２、被検液体の誘電
率をεとすると、内、外筒間に形成される電極間静電容
量Ｃは、
＝ＫＸ（ｆｉ＋Δ℃（ε−１）） ・・・・・
・・・・（１）で表わされることが知られている。この
結果、検出された静電容量Ｃを周波数変換、電圧変換等
を行なうことによって、液面高さ６文を測定し、または
当該液面高さΔ見に対応する貯液タンク内液面を測定す
ることができる。In other words, look at the axial length of the outer cylinder and inner cylinder, and calculate the liquid level height by Δ,
When the inner diameter of the outer cylinder is di, the outer diameter of the inner cylinder is d2, and the dielectric constant of the liquid to be tested is ε, the interelectrode capacitance C formed between the inner and outer cylinders is: =KX(fi+Δ℃(ε -1)) ・・・・・・
It is known that it is expressed by (1). As a result, by performing frequency conversion, voltage conversion, etc. on the detected capacitance C, the liquid level height 6 can be measured, or the liquid level in the liquid storage tank corresponding to the liquid level height Δ can be measured. can be measured.
ここで、（１）式から明らかなように液面センサの電極
間静電容量Ｃは被検液体の誘電率εの関数であり、従っ
て測定された液面高さも誘電率（の関数である。Here, as is clear from equation (1), the interelectrode capacitance C of the liquid level sensor is a function of the dielectric constant ε of the liquid to be tested, and therefore the measured liquid level height is also a function of the dielectric constant ( .
然るに、従来技術による液面測定装置においては、例え
ばガソリン、軽油等の被検液体の誘電率εは、その種類
によってほぼ一定とされる公称値を予め定数として付与
した上で、静電容量Ｃを検出し、液面高さを演算するの
が普通である。However, in a liquid level measuring device according to the prior art, the dielectric constant ε of the liquid to be tested, such as gasoline or diesel oil, is determined by setting the capacitance C to a nominal value that is approximately constant depending on the type of liquid. It is normal to detect the liquid level and calculate the liquid level height.
しかし、実際には被検液体が持っている真の誘電率ｅ（
実効誘電率）は、原油の産地、各製油所毎にバラツキが
あり、公称値とは個々に異なっており、当該公称値に基
づいて液面検出を行なっても正確な測定ができないとい
う問題点がある。−方、演算装置に定数として誘電率ε
を設定、入力するとき、入力手続上の錯誤等によって異
なった定数を設定した場合には常に誤った演算結果が出
力されるという問題点がある。However, in reality, the true dielectric constant e(
The problem is that the effective dielectric constant (effective dielectric constant) varies depending on the region of crude oil production and each refinery, and is different from the nominal value for each oil refinery.Accurate measurements cannot be made even if liquid level is detected based on the nominal value. There is. − On the other hand, the dielectric constant ε is used as a constant in the arithmetic unit.
When setting and inputting , there is a problem that if a different constant is set due to an error in the input procedure, an incorrect calculation result will always be output.
本発明はこのような従来技術の問題点に鑑みなされたも
ので、貯液タンクに貯えられた被検液体の実効誘電率を
、液面センサを構成する内筒を用いて、かつスイッチ切
換のみによって手動または自動的に測定し、この測定結
果を正確な定数として演算装置に与えることができるよ
うにした静電容量式液面測定装置を提供することを目的
とするものである。The present invention was developed in view of the problems of the prior art, and it is possible to measure the effective dielectric constant of a liquid to be tested stored in a liquid storage tank by using an inner cylinder that constitutes a liquid level sensor, and by simply changing a switch. It is an object of the present invention to provide a capacitance type liquid level measuring device that can perform manual or automatic measurement using the above method and provide the measurement results as accurate constants to an arithmetic device.
上記目的を達成するために、本発明は、貯液タンク内に
挿入される外筒と内筒とからなる同軸円筒形の液面セン
サを有し、液面高さに応じて該液面センサの外筒と内筒
との間に形成される電極間静電容量に基づいて液面高さ
を測定するようにした静電容量式液面測定装置において
、前記液面センサを１本の外筒と、上部内筒と下部内筒
からなる２本の内筒とによって形成し、該内湾の上部内
筒と下部内筒との間に絶縁部材を介挿し、前記外筒、上
部内筒および下部内筒と演算装置との間をそれぞれ信号
線を介して接続し、かつ前記下部内筒を誘電率測定用セ
ンサを兼ねさせるため、前記上部内筒と下部内筒を演算
装置に接続する信号線の途中に切換スイッチを設けたこ
とを特徴とする。In order to achieve the above object, the present invention has a coaxial cylindrical liquid level sensor consisting of an outer cylinder and an inner cylinder that are inserted into a liquid storage tank, and the liquid level sensor according to the liquid level height. In a capacitive liquid level measuring device that measures a liquid level based on an interelectrode capacitance formed between an outer cylinder and an inner cylinder, the liquid level sensor is connected to one external cylinder. It is formed by a cylinder and two inner cylinders consisting of an upper inner cylinder and a lower inner cylinder, and an insulating member is inserted between the upper inner cylinder and the lower inner cylinder of the inner bay, and the outer cylinder, the upper inner cylinder and A signal for connecting the upper inner cylinder and the lower inner cylinder to the arithmetic unit in order to connect the lower inner cylinder and the arithmetic unit via signal lines, and to make the lower inner cylinder also serve as a dielectric constant measurement sensor. It is characterized by a changeover switch installed in the middle of the line.
このように構成することにより、例えば貯液タンク内を
満タンにする都度、切換スイッチを操作して下部内筒の
みを演算装置と接続し、その時の電極間静電容量を測定
すれば、当該静電容量から誘電率を求めることができる
。一方、液面高さを測定するときには、切換スイッチに
よって上、下の内筒を共に演算装置と接続し、１本の内
筒とみなすことによって外筒との間に形成される静電容
量から通常の液面測定が可能となる。With this configuration, for example, every time the liquid storage tank is filled up, you can operate the changeover switch to connect only the lower inner cylinder to the calculation device and measure the interelectrode capacitance at that time. Dielectric constant can be determined from capacitance. On the other hand, when measuring the liquid level height, the upper and lower inner cylinders are both connected to the calculation device using a changeover switch, and the capacitance formed between them and the outer cylinder is calculated by considering them as one inner cylinder. Normal liquid level measurement becomes possible.
以下、本発明の実施例を添付図面を参照しつつ、詳細に
述べる。Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
図面において、ｌは貯液タンク、２は該貯液タンクｌ内
に貯えられた液体、３はその液面、４は貯液タンクｌ内
に挿入された同軸円筒形の液面センサを示す、そして、
該液面センサ４は、１本の筒体からなる外筒５と、該外
筒５内に同軸に挿入された内筒６とを有し、該内筒６は
上部内筒６Ａと下部内筒６Ｂとの２本の筒体からなり、
該上部内筒６Ａの下端と下部内筒６Ｂの上端は絶縁部材
７を介して接続されている。また、８は外筒５と下部内
筒６Ｂの下端に設けられた絶縁部材で。In the drawing, l indicates a liquid storage tank, 2 indicates the liquid stored in the liquid storage tank l, 3 indicates the liquid level, and 4 indicates a coaxial cylindrical liquid level sensor inserted into the liquid storage tank l. and,
The liquid level sensor 4 has an outer cylinder 5 made of one cylinder, and an inner cylinder 6 coaxially inserted into the outer cylinder 5. The inner cylinder 6 has an upper inner cylinder 6A and a lower inner cylinder. It consists of two cylinders with cylinder 6B,
The lower end of the upper inner cylinder 6A and the upper end of the lower inner cylinder 6B are connected via an insulating member 7. Further, 8 is an insulating member provided at the lower ends of the outer cylinder 5 and the lower inner cylinder 6B.
該絶縁部材８は貯液タンク１の底面に着座しており、一
方、９は外筒５と上部内筒６Ａの上端に設けられた他の
絶縁部材で、該絶縁部材９は貯液りンクｌの上面かられ
ずかに突出している。The insulating member 8 is seated on the bottom surface of the liquid storage tank 1, and 9 is another insulating member provided at the upper end of the outer cylinder 5 and the upper inner cylinder 6A. It slightly protrudes from the top surface of l.
１０は演算装置を示し、該演算装置ｌＯは後述するよう
に検出された静電容量に基づいて液面高さを演算すると
共に誘電率（を演算する演算回路１１と、スイッチ１２
Ａ、１２Ｂを有する切換スイッチ１２とから構成され、
入力側は信号線１３．１４．１５を介して外筒５．上部
内筒６Ａ、下部内筒６Ｂとそれぞれ接続され、出力側は
液面計１６と接続されている。Reference numeral 10 indicates a calculation device, and the calculation device IO calculates the liquid level height based on the detected capacitance as described later, and also includes a calculation circuit 11 that calculates the dielectric constant, and a switch 12.
A, a changeover switch 12 having 12B,
The input side is connected to the outer cylinder 5 through signal lines 13, 14, and 15. It is connected to the upper inner cylinder 6A and the lower inner cylinder 6B, respectively, and the output side is connected to the liquid level gauge 16.
ここで、前記切換スイッチ１２のスイッチ１２Ａは信号
線１４の途中に設けられ、スイッチ１２Ｂは信号線１５
の途中に設けられ、かつこれら信号線１４．１５は接続
点１７で結線された後演算回路１１と接続されるように
なっている。この結果、外筒５と上部内筒６Ａによって
形成される静電容量をＣａ、外筒５と下部内筒６Ｂによ
って形成される静電容量をＣｂ とするとき、スイッチ
１２Ａ、１２Ｂを閉成した状態ではこれら静電容量Ｃａ
、Ｃｂは電気的に並列接続されることになる。Here, the switch 12A of the changeover switch 12 is provided in the middle of the signal line 14, and the switch 12B is provided in the middle of the signal line 14.
These signal lines 14 and 15 are connected at a connection point 17 and then connected to the arithmetic circuit 11. As a result, when the capacitance formed by the outer cylinder 5 and the upper inner cylinder 6A is Ca, and the capacitance formed by the outer cylinder 5 and the lower inner cylinder 6B is Cb, the switches 12A and 12B are closed. In the state, these capacitances Ca
, Cb are electrically connected in parallel.
本実施例はこのように構成されるが１次にその作動につ
いて述べる。The present embodiment is constructed as described above, but its operation will be described first.
いま、図面に示すように、貯液タンク１内には液体２が
ほぼ満タン状態で貯えられ、その液面３は上部内筒６Ａ
の軸方向中間位置にあるものとする。Now, as shown in the drawing, the liquid 2 is stored in the liquid storage tank 1 in an almost full state, and the liquid level 3 is above the upper inner cylinder 6A.
It shall be at an intermediate position in the axial direction.
そして、上部内筒６Ａの長さを文４、下部内筒６Ｂの長
さをｌｂ とし、外筒５の内径ｄ１ と内筒６の外径ｄ
２ とにより定まる定数Ｋを。Then, let the length of the upper inner cylinder 6A be 4, the length of the lower inner cylinder 6B be lb, and the inner diameter d1 of the outer cylinder 5 and the outer diameter d of the inner cylinder 6.
2 and the constant K determined by.
従来技術のものと同様に静電容量Ｃａ、Ｃｂを測定する
。Capacitances Ca and Cb are measured in the same manner as in the prior art.
まず、外筒５と上部内筒６Ａとの間に形成される静電容
量Ｃａを測定するには、切換スイッチ１２のスイッチ１
２Ａを閉成し、スイッチ１２Ｂを開成する。これにより
、上部内筒６Ａが液体２に浸っている長さをΔ見ａ、空
気の誘電率をε０、液体２の誘電率をεとすると、前記
静電容量Ｃａは、
Ｃａ＝Ｋｘ（Δム×ε＋（Ｌ３−ΔＩｔｓ ）Ｘｇｏｌ
＋ｍ＊＋ （２）となり、空気の誘電率ε０は、εｏ
４−ｐｌであるから、（２）式は下記（３）式となる。First, in order to measure the capacitance Ca formed between the outer cylinder 5 and the upper inner cylinder 6A, switch 1 of the changeover switch 12
2A is closed and switch 12B is opened. As a result, when the length of the upper inner cylinder 6A immersed in the liquid 2 is Δa, the dielectric constant of air is ε0, and the dielectric constant of the liquid 2 is ε, the capacitance Ca is calculated as follows: Ca=Kx(Δ M×ε+(L3−ΔIts)Xgol
+m*+ (2), and the dielectric constant ε0 of air is εo
4-pl, the equation (2) becomes the following equation (3).
Ｃａ ＝Ｋ Ｘ Ｉ Ｉｌａ＋Δム（ε−１）） ・・
・・・・・・・・・・（３）次に、外筒５と下部内筒６
Ｂとの間に形成される静電容量Ｃｂを測定するには、切
換スイッチ１２のスイッチ１２Ａを開成し、スイッチ１
２Ｂを閉成する。この際、下部内筒６Ｂはその全長ｌｂ
にわたって液体２に浸っているから、前記静電容量Ｃｂ
は、下記（４）式となる。Ca=KXIIla+Δm(ε-1))...
・・・・・・・・・・・・(3) Next, the outer cylinder 5 and the lower inner cylinder 6
To measure the capacitance Cb formed between
Close 2B. At this time, the lower inner cylinder 6B has a total length of lb
Since the capacitance Cb is immersed in the liquid 2, the capacitance Cb
is the following equation (4).
Ｃｂ＝ＫＸｆｉｂＸε ・・・・・・・・・・
・・・・・（４）さらに、外筒５と内筒６によって形成
される全静電容量ＣＳを測定するには、切換スイッチ１
２のスイッチ１２Ａ、１２Ｂを共に閉成する。これによ
り、全静電容量Ｃ５は、（３）式、（４）式から、
Ｃｓ ” Ｃａ ＋ ｃｂ
＝に×（ム＋ｉｂ＋ （ｘｂ十ΔＬ３）Ｘ（ε−１））
・・・・・・・・・・・・（５）
として検出しうる。ここで、（５）式中の（ｌｂ＋Δｉ
ａ）は上部内筒６Ａと下部内筒６Ｂが液体２に浸ってい
る長さであり、（ε−１）なる誘電率を含む以外は定数
であるから、（ε−１）が正確に検出でき、全静電容量
ＣＳが求められｈば、液面高さ（Ｊｌｂ＋ΔＵａ）を測
定することができる。Cb=KXfibXε ・・・・・・・・・・・・
...(4) Furthermore, in order to measure the total capacitance CS formed by the outer cylinder 5 and the inner cylinder 6, selector switch 1
The two switches 12A and 12B are both closed. As a result, the total capacitance C5 is calculated as follows from equations (3) and (4):
・・・・・・・・・・・・(5) It can be detected as follows. Here, (lb+Δi
a) is the length of the upper inner cylinder 6A and lower inner cylinder 6B immersed in the liquid 2, and since it is a constant except for the dielectric constant (ε-1), (ε-1) can be detected accurately. If the total capacitance CS is determined, the liquid level height (Jlb+ΔUa) can be measured.
一方、上記の説明は貯液タンク１内の液面３が図面に示
す状態について述べたが、液面３が下部内筒６Ｂの途中
まで下がってくると、上部内筒６Ａは液面に浸らないか
ら、その静電容量Ｃａ／は。On the other hand, in the above explanation, the liquid level 3 in the liquid storage tank 1 is in the state shown in the drawing, but when the liquid level 3 falls halfway down the lower inner cylinder 6B, the upper inner cylinder 6A is submerged in the liquid level. Since there is no, its capacitance Ca/ is.
Ｃａ’ ” Ｋ Ｘ Ｌｌ ・・・・・・・・・・・
・・・・・・・（６）となり、下部内筒６Ｂの静電容量
Ｃｂ’は（３）式と同様に、
ｃｂ／ ＝ ＫＸ ｉ Ｘｂ＋Δｌｂ（ε−１））・・
・・・・（７）として求められる。従って、切換スイッ
チ１２のスイッチ１２Ａ、１２Ｂを共に閉成したときの
全静電容量Ｃ３は、（６）式、（７）式から、Ｃｓ ”
Ｃａ’ ＋ ｃｂ’
＝に×（ム＋２ｂ＋ΔＩｂ（ε−１）） ・・・・・曲
（８）となり、これは（５）式の（文ｂ＋Δｕａ）をΔ
ｆＬｂ としたものである。Ca' ” K X Ll ・・・・・・・・・・・・
(6), and the capacitance Cb' of the lower inner cylinder 6B is as in equation (3), cb/ = KX i Xb + Δlb (ε-1))...
...It is obtained as (7). Therefore, from equations (6) and (7), the total capacitance C3 when both switches 12A and 12B of the changeover switch 12 are closed is Cs ''
Ca' + cb' = × (mu + 2b + ΔIb (ε-1)) ... Song (8) is obtained, which means that (sentence b + Δua) in equation (5) is
fLb.
かくすれば、貯液タンクｌ内の全液面高さの範囲にわた
る一般式は、
Ｃｓ ＝ ＫＸ （（ｆｌａ＋Ｉｌｂ ）＋（Δム＋Δ
ｌｂ ） Ｘ （ε−１）ｌ−（９１となり、上部内筒
６Ａと下部内筒６Ｂとを一本の内筒６とみなし、
と考えることにより、（１）式で示した従来技術のもの
と同様に液面検出することができる。Thus, the general formula over the range of total liquid level heights in storage tank l is: Cs = KX ((fla + Ilb) + (Δm + Δ
lb) The liquid level can be detected in the same way.
而して、上部内筒６Ａが液体２に浸っていない状態、即
ちΔ１ａ＝ｏのときの静電容量ｃａ′は、（６）式から
明らかなように誘電率（を含まず、全て定数により定ま
る既知の値である。−方、上部内筒６Ａが液体２に浸っ
ている状態の静電容量Ｃａは（３）式である。従って、
切換スイッチ１２のスイッチ１２Ａを閉成し、スイッチ
１２Ｂを開成することにより、演算回路ｌｌ側において
、
Ｃａ ＞ Ｃａ’ −−−”（１１）と判定したき
きには、液面３は上部内筒６Ａの下面位置よりも高く、
下部内筒６Ｂは全部液体２に浸っている位置にあること
を表わしている。Therefore, as is clear from equation (6), when the upper inner cylinder 6A is not immersed in the liquid 2, that is, when Δ1a=o, the capacitance ca' does not include the dielectric constant, and is all determined by constants. It is a fixed and known value. On the other hand, the capacitance Ca when the upper inner cylinder 6A is immersed in the liquid 2 is expressed by equation (3). Therefore,
By closing the switch 12A of the changeover switch 12 and opening the switch 12B, when the arithmetic circuit 11 side determines that Ca >Ca'---'' (11), the liquid level 3 is lower than the upper inner cylinder. Higher than the bottom position of 6A,
The lower inner cylinder 6B is shown to be completely immersed in the liquid 2.
そこで、液面高さが（１１）式を満足する状態にあると
き、例えば貯液タンクｌが満タン状態にあるとき、切換
スイッチ１２のスイッチ１２Ａを開成し、スイッチ１２
Ｂを閉成して、（４）式による静電容量Ｃｂ ！測定し
、誘電率εを、Ｃｂ
ε＝に′×−・・・・・・・・・（１２）Ｃｂ
ただし、Ｋ’＝１／に
として求めることができる。Therefore, when the liquid level satisfies equation (11), for example when the liquid storage tank l is full, the switch 12A of the changeover switch 12 is opened, and the switch 12A is opened.
B is closed, and the capacitance Cb ! according to equation (4) is obtained. The dielectric constant ε can be determined as Cb ε=′×− (12)Cb where K′=1/.
ところで、貯液タンク１に貯えられる液体は、消費され
て新たに補給される度毎に実効誘電率が異なるのが一般
的であり、また新たに補給するときにはほぼ満タンにす
るのが通例である。By the way, the liquid stored in the liquid storage tank 1 generally has a different effective dielectric constant each time it is consumed and refilled, and it is customary for the liquid to be almost full when refilled. be.
従って、貯液タンクｌに液体２を補給する都度、切換ス
イッチ１２の操作によって（１１）式の条件を確認した
後、（４）式で静電容量Ｃｂを求め、（１２）式から誘
電率εを求めれば、以後貯液タンク１内の液体２が消費
され、次に補給するまでの間、この求めた誘電率を（９
）式に使用して液面高さを演算することができ、高精度
な液面検出が可能となる。Therefore, each time the liquid 2 is replenished into the liquid storage tank 1, after confirming the conditions of equation (11) by operating the changeover switch 12, the capacitance Cb is determined using equation (4), and the dielectric constant is determined from equation (12). Once ε has been determined, the dielectric constant obtained can be expressed as (9
) can be used to calculate the liquid level height, allowing highly accurate liquid level detection.
しかも、下部内筒６Ｂは貯液タンク１の高さ寸法の８０
％位まで長くすることが可能であり、当該下部内筒６Ｂ
の長さが大であるということは（１２）式におけるＩＬ
ｂ、Ｃｂが大となるから、誘電率（の値も確度高く求め
ることができる。Moreover, the lower inner cylinder 6B has a height dimension of 80 mm, which is equal to the height of the liquid storage tank 1.
It is possible to lengthen up to about %, and the lower inner cylinder 6B
The fact that the length of is large means that IL in equation (12)
Since b and Cb are large, the value of the dielectric constant can also be determined with high accuracy.
なお、切換スイッチ１２を自動切換スイッチとすると共
に演算回路１１をマイクロコンピュータにより構成し、
前記した一連の動作を例えば第２図、第３図に示すプロ
グラムに組込むことによって、自動液面測定装置を構成
することができる。Note that the changeover switch 12 is an automatic changeover switch, and the arithmetic circuit 11 is configured by a microcomputer.
By incorporating the series of operations described above into the programs shown in FIGS. 2 and 3, for example, an automatic liquid level measuring device can be constructed.
また、実施例では液面センサ４として液面専用センサを
例示したが、例えば特公昭８０−３５１１１１４号公報
に示される如く、貯液タンク１内底部に溜る水面高さも
測定可能な液面センサにも応用しうるちのである。In addition, in the embodiment, a sensor dedicated to the liquid level is used as the liquid level sensor 4, but as shown in Japanese Patent Publication No. 80-3511114, a liquid level sensor that can also measure the height of the water level accumulated at the inner bottom of the liquid storage tank 1 may be used. It can also be applied.
一方、上部内筒６Ａと下部内筒６Ｂは絶縁部材７を介し
て接続されているから、液面が該絶縁部材７の位置以上
に高くなると、理論的には静電容量と液面高さとの間に
段差ができるが、実用的には無視できる程度の値とする
ことができる。On the other hand, since the upper inner cylinder 6A and the lower inner cylinder 6B are connected via the insulating member 7, when the liquid level becomes higher than the position of the insulating member 7, the capacitance and the liquid level height theoretically increase. Although there is a difference in level between the two, the value can be practically ignored.
さらに、本発明の液面測定装置は、タンク内残量測定装
置も含む概念として定義されることは勿論である。Furthermore, it goes without saying that the liquid level measuring device of the present invention is defined as a concept that also includes a tank remaining amount measuring device.
本発明に係る静電容量式液面測定装置は以上詳細に述べ
た如くであって、内筒を上部内筒と下部内筒とからなる
分割型の内筒とし、切換スイッチによる切換操作で誘電
率測定用センサを兼用させることができるから、貯液タ
ンク内に貯えられている液体の実効誘電率を測定し、こ
の測定結果に基づいて液面高さの測定が可能であり、正
確な液面検出を行なうことができ、かつ別途誘電率測定
用センサを備える必要もなく、コスト上、設置工事上多
大な効果を発揮する。The capacitance type liquid level measuring device according to the present invention is as described in detail above, and the inner cylinder is a split type inner cylinder consisting of an upper inner cylinder and a lower inner cylinder. Since the sensor can also be used to measure the liquid, it is possible to measure the effective dielectric constant of the liquid stored in the liquid storage tank, and measure the liquid level based on this measurement result, making it possible to accurately measure the liquid level. It is possible to perform surface detection, and there is no need to provide a separate dielectric constant measurement sensor, which is highly effective in terms of cost and installation work.
第１図は実施例による静電容量式液面測定装置を示す全
体構成図、第２図は液面測定処理を示す流れ図、第３図
は誘電率測定処理を示す流れ図である。
１・・・貯液タンク、２・・・液体、３・・・液面、４
・・・液面センサ、５・・・外筒、６・・・内筒、６Ａ
・・・上部内筒、６Ｂ・・・下部内筒、７，８．９・・
・絶縁部材、１０・・・演算装置、１１・・・演算回路
、１２・・・切換スイッチ。
第２図 第３図FIG. 1 is an overall configuration diagram showing a capacitive liquid level measuring device according to an embodiment, FIG. 2 is a flowchart showing a liquid level measurement process, and FIG. 3 is a flowchart showing a dielectric constant measurement process. 1...Liquid storage tank, 2...Liquid, 3...Liquid level, 4
...Liquid level sensor, 5...Outer cylinder, 6...Inner cylinder, 6A
... Upper inner cylinder, 6B... Lower inner cylinder, 7, 8.9...
- Insulating member, 10... Arithmetic device, 11... Arithmetic circuit, 12... Changeover switch. Figure 2 Figure 3
Claims (1)
筒形の液面センサを有し、液面高さに応じて該液面セン
サの外筒と内筒との間に形成される電極間静電容量に基
づいて液面高さを測定するようにした静電容量式液面測
定装置において、前記液面センサを１本の外筒と、上部
内筒と下部内筒からなる２本の内筒とによって形成し、
該内筒の上部内筒と下部内筒との間に絶縁部材を介挿し
、前記外筒、上部内筒および下部内筒と演算装置との間
をそれぞれ信号線を介して接続し、かつ前記下部内筒を
誘電率測定用センサを兼ねさせるため、前記上部内筒と
下部内筒を演算装置に接続する信号線の途中に切換スイ
ッチを設けたことを特徴とする静電容量式液面測定装置
。It has a coaxial cylindrical liquid level sensor consisting of an outer cylinder and an inner cylinder inserted into a liquid storage tank, and a liquid level sensor is formed between the outer cylinder and the inner cylinder according to the liquid level height. In a capacitive liquid level measuring device that measures the liquid level based on the capacitance between electrodes, the liquid level sensor is composed of an outer cylinder, an upper inner cylinder, and a lower inner cylinder. Formed by two inner cylinders,
An insulating member is inserted between the upper inner cylinder and the lower inner cylinder of the inner cylinder, and the outer cylinder, the upper inner cylinder, and the lower inner cylinder are connected to the arithmetic device through signal lines, and the A capacitance type liquid level measurement characterized in that a changeover switch is provided in the middle of a signal line connecting the upper inner cylinder and the lower inner cylinder to an arithmetic unit so that the lower inner cylinder also serves as a sensor for measuring dielectric constant. Device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63049382A JPH01223316A (en) | 1988-03-02 | 1988-03-02 | Electrostatic capacity type liquid level measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63049382A JPH01223316A (en) | 1988-03-02 | 1988-03-02 | Electrostatic capacity type liquid level measuring apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01223316A true JPH01223316A (en) | 1989-09-06 |
| JPH05649B2 JPH05649B2 (en) | 1993-01-06 |
Family
ID=12829470
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63049382A Granted JPH01223316A (en) | 1988-03-02 | 1988-03-02 | Electrostatic capacity type liquid level measuring apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01223316A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5860316A (en) * | 1995-09-16 | 1999-01-19 | Rolls-Royce And Associates Limited | Capacitance probe |
| CN104296832A (en) * | 2014-11-06 | 2015-01-21 | 上海雷尼威尔技术有限公司 | LNG (liquefied natural gas) storage tank liquid level measuring method and equipment |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5640721A (en) * | 1979-09-12 | 1981-04-17 | Esu Hedoriku Jiefuri | Fluid quantity indicator |
| JPS5842926A (en) * | 1981-09-07 | 1983-03-12 | Tokyo Tatsuno Co Ltd | Electrostatic capacity type oil level gauge |
-
1988
- 1988-03-02 JP JP63049382A patent/JPH01223316A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5640721A (en) * | 1979-09-12 | 1981-04-17 | Esu Hedoriku Jiefuri | Fluid quantity indicator |
| JPS5842926A (en) * | 1981-09-07 | 1983-03-12 | Tokyo Tatsuno Co Ltd | Electrostatic capacity type oil level gauge |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5860316A (en) * | 1995-09-16 | 1999-01-19 | Rolls-Royce And Associates Limited | Capacitance probe |
| CN104296832A (en) * | 2014-11-06 | 2015-01-21 | 上海雷尼威尔技术有限公司 | LNG (liquefied natural gas) storage tank liquid level measuring method and equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05649B2 (en) | 1993-01-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU2424495C1 (en) | Continuous action level gauge for measuring level of liquid in steam drum under any working conditions and method of determining level of liquid using said level gauge | |
| US7421896B2 (en) | Variable frequency charge pump in capacitive level sensor | |
| US4555661A (en) | Method and apparatus for determining dielectric constant | |
| US4399699A (en) | Electrostatic type fuel measuring device | |
| US20200333175A1 (en) | Dual Polarity Mutual Capacitive Liquid Sensing | |
| US4021707A (en) | Compensated probe for capacitive level measurement | |
| US4178623A (en) | Measuring sensor for capacitive measurement of liquids at selected levels | |
| US3283577A (en) | Divided capacitance probe level gauge | |
| NO165267B (en) | NIVAAMAALER. | |
| JPH01223316A (en) | Electrostatic capacity type liquid level measuring apparatus | |
| CN2622681Y (en) | Self-calibration and capacitor type level gage | |
| US2919579A (en) | Electrically-conductive liquid level measuring system | |
| CN107449489A (en) | A kind of fuel level sensor and oil level measuring device for vehicle | |
| JP3368508B2 (en) | Level measuring method and level measuring instrument | |
| CN110646061A (en) | Double-path redundant intelligent calibration radio frequency admittance anti-overflow liquid level meter and measurement method thereof | |
| JP2511334B2 (en) | Measurement accuracy inspection method for capacitance type liquid level gauge | |
| CN103353324A (en) | Self-calibrated capacitive liquid level sensor | |
| US2754457A (en) | L liij | |
| CN203396459U (en) | Self-correction capacitance liquid level sensor | |
| CN207263261U (en) | A kind of fuel level sensor and oil level measuring device for vehicle | |
| JPS5819457Y2 (en) | Split electrode capacitance level meter | |
| CN201094069Y (en) | Measuring rapier of liquid level measurer | |
| JP5900704B2 (en) | Capacitive fuel level gauge with float | |
| US3228245A (en) | Liquid quantity gage | |
| RU2042928C1 (en) | Capacitor level meter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |