JPH04125423A - Lateral leakage optical fiber type level gage - Google Patents
Lateral leakage optical fiber type level gageInfo
- Publication number
- JPH04125423A JPH04125423A JP24654190A JP24654190A JPH04125423A JP H04125423 A JPH04125423 A JP H04125423A JP 24654190 A JP24654190 A JP 24654190A JP 24654190 A JP24654190 A JP 24654190A JP H04125423 A JPH04125423 A JP H04125423A
- Authority
- JP
- Japan
- Prior art keywords
- light
- optical fiber
- liquid
- leakage
- amount
- 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
- 239000013307 optical fiber Substances 0.000 title claims abstract description 22
- 239000007788 liquid Substances 0.000 claims abstract description 30
- 238000005259 measurement Methods 0.000 abstract description 5
- 238000000034 method Methods 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 238000005253 cladding Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000000691 measurement method Methods 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】
本発明は側方漏洩光ファイバーを用いた液位泪に関する
。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to liquid level tearing using side-leaking optical fibers.
従来のこの種の技術にあっては、光ファイバーの端面か
らの出力光を液面に照射し、この液面からの反射光量若
しくは光の往復時間や変調信号の位相差を検出して液位
を計測する方式のものがあったが、これらの方式にあっ
ては、光の強度は距離の４乗に逆比例して減少するので
、この大幅な減衰をカバーするだけの大出力光源が必要
であり、それに相応してコストアップを招くという問題
点があった。In conventional technology of this kind, the liquid level is determined by irradiating the liquid surface with output light from the end face of an optical fiber, and detecting the amount of light reflected from the liquid surface, the round trip time of the light, and the phase difference of the modulated signal. There were methods to measure the distance, but with these methods, the intensity of the light decreases in inverse proportion to the fourth power of the distance, so a high-output light source was required to cover this significant attenuation. However, there is a problem in that the cost increases accordingly.
また、前者の液面からの反射光量を計測する方式にあっ
ては、液面に波立、傾斜、動揺などがある場合には光の
反射条件が変動するので正確な計測が難しくなるという
問題点があった。Another problem with the former method of measuring the amount of light reflected from the liquid surface is that if the liquid surface is rippled, tilted, or oscillated, the light reflection conditions will change, making accurate measurement difficult. was there.
一方、後者の光の往復時間や変調信号の位相差を計測す
るレーダ一方式にあっては、複雑な検出回路が必要なた
め高価になるという問題点があった。On the other hand, the latter type of radar, which measures the round trip time of light and the phase difference of modulated signals, has the problem of being expensive because it requires a complicated detection circuit.
この発明はこれらの問題点を解決するためになされたも
のである。This invention was made to solve these problems.
本発明は、光ファイバーの側方から光が漏洩するように
なされた側方漏洩光ファイバーの一端から光を投入し、
他端からの出力光量を計測するように構成し、該光ファ
イバーの一部を液体に浸すとき、液体に浸された部分と
浸されない部分の光の漏洩量に差異が生じる性質を利用
して液位を計測するようにした。The present invention introduces light from one end of a side-leaking optical fiber that allows light to leak from the side of the optical fiber,
It is configured to measure the amount of light output from the other end, and uses the property that when a part of the optical fiber is immersed in liquid, there is a difference in the amount of light leaking between the part immersed in the liquid and the part not immersed in the liquid. The position can be measured.
本発明によれば、上記問題点を解決し、構造が極めて簡
単で、計測精度が高く、且つ安価な液位計を得ることが
できる。According to the present invention, it is possible to solve the above-mentioned problems and obtain a liquid level meter that has an extremely simple structure, high measurement accuracy, and is inexpensive.
以下発明の詳細について図面と共に説明する。The details of the invention will be explained below with reference to the drawings.
第１図は本発明の原理説明図であり、ＬＥＤ、レーザー
、若しくは電球などからなる光源１からの光は側方漏洩
光ファイバー２の光入力端３に入力され、該光ファイバ
ー２の中を通過して光出力端４から出力されて受光器５
に入り、ここで電気信号に変換されて増幅・変換器６を
介してデジタル式若しくはアナログ式の表示器７に接続
されている。そして、該光ファイバー２は、その長手方
向単位長当たりの光の漏洩量がほぼ一定になるように加
工されている。以上のような構成の本発明の実施例にお
いて、該光ファイバー２のある部分が空気８中にあり、
他の部分が液体９中にあるとき、空気と液体の光に対す
る屈折率が異なるため、即ち光の漏洩経路における負荷
インピーダンスが異なることにより、単位長当たりの空
中漏洩量１０と液中漏洩量】１とは異なったものとなる
。FIG. 1 is a diagram explaining the principle of the present invention, in which light from a light source 1 consisting of an LED, a laser, a light bulb, etc. is input to the light input end 3 of a side leakage optical fiber 2, and passes through the optical fiber 2. The light is output from the light output end 4 and sent to the light receiver 5.
There, the signal is converted into an electrical signal and connected via an amplifier/converter 6 to a digital or analog display 7. The optical fiber 2 is processed so that the amount of light leakage per unit length in the longitudinal direction is approximately constant. In the embodiment of the present invention configured as described above, a certain portion of the optical fiber 2 is in the air 8,
When the other parts are in the liquid 9, the air and liquid have different refractive indices for light, that is, the load impedance on the light leakage path is different, so the amount of air leakage per unit length and the amount of leakage in the liquid] It will be different from 1.
この状況を第２図及び第３図に示す電気的等価回路によ
って説明すればより解りやすくなる。This situation will be easier to understand if explained using the electrical equivalent circuits shown in FIGS. 2 and 3.
第２図は、該光ファイバー２がすべて空気中にある場合
の等価回路であり、光源１からの入力光Ｐは空気に対す
る漏洩インピーダンス２．．２２、・・・、Ｚヨ、Ｚｎ
を介して空中に漏洩し、残りの出力光Ｒが受光器５に
入力される。一方策３図は１図中のＣ−Ｃ線とＤ−Ｄ＠
の間が液中にある場合を示し、この区間の漏洩インピー
ダンスは液体に対する漏洩インピーダンスＺ２＋・・・
ｇ Ｚ、に変わり、したがって出力光もＲからｒに変
わる。FIG. 2 shows an equivalent circuit when all of the optical fibers 2 are in the air, and the input light P from the light source 1 has a leakage impedance of 2. ．． 22, ..., Zyo, Zn
The remaining output light R is input into the light receiver 5. On the other hand, Figure 3 is the C-C line in Figure 1 and D-D@
Indicates the case where the area between is in the liquid, and the leakage impedance in this area is the leakage impedance to the liquid Z2+...
g Z, and therefore the output light also changes from R to r.
液位が上下に変化すると、即ちＣ−Ｃ線とＤＤ線の間隔
が変わると、当然ｒの値が変わるのでこのｒの値から液
位が検出できることになる。When the liquid level changes up and down, that is, when the interval between the C-C line and the DD line changes, the value of r naturally changes, so the liquid level can be detected from this value of r.
第４図乃至第６図は共に側方漏洩光ファイバー２の構成
例を示し、第４図に示すようにコア１２の外側を取り巻
くクラッド１３の一部をＡ−Ａ面で削除すれば、この削
除面から光が漏洩するようになるし、また第５図Ｂのよ
うに、クラッド１３の適宜の位置に、適宜の寸法及び深
さの孔を穿つてもよい。更に第６図に示すように、光コ
アイノく−を一定値以下の曲率半径で湾曲させれば、光
ファイバーの側面から光が漏洩するようになる。これら
の他、クラッドを薄くシて光が側方から漏洩するように
予め設計・製作した光ファイバーを使用しても良い。4 to 6 both show configuration examples of the side leakage optical fiber 2. If a part of the cladding 13 surrounding the outside of the core 12 is removed in the A-A plane as shown in FIG. Light leaks from the surface, and holes of appropriate dimensions and depth may be bored at appropriate positions in the cladding 13, as shown in FIG. 5B. Furthermore, as shown in FIG. 6, if the optical core is curved with a radius of curvature below a certain value, light will leak from the side surface of the optical fiber. In addition to these, it is also possible to use an optical fiber designed and manufactured in advance so that the cladding is thin so that light leaks from the sides.
以上説明したように、本発明による計測方法によれば、
液面からの光の反射を利用しないので、液面の影＠を受
けにくく、正確な計測を行なうことができると共に、光
は空間を往復する必要がなく光フアイバー中を片道進行
するだけなので往復方式に比べて小出力の光源でよく、
更にレーダー方式のような複雑高価な回路を使用する必
要もないので、低価格化が実現できる。As explained above, according to the measurement method according to the present invention,
Since it does not utilize the reflection of light from the liquid surface, it is less likely to be affected by shadows on the liquid surface, allowing for accurate measurements.In addition, the light does not need to travel back and forth in space, but only travels one way through the optical fiber, so it can be used in both directions. Compared to the method, a light source with a lower output is required,
Furthermore, since there is no need to use complicated and expensive circuits like the radar system, the cost can be reduced.
以上説明したように、本発明によれば構造が簡単で、計
測精度の高く、かつ安価な液位計を提供できるので産業
上の効果は非常に大きい。As explained above, according to the present invention, it is possible to provide a liquid level meter that has a simple structure, high measurement accuracy, and is inexpensive, and therefore has a very large industrial effect.
第１図は原理説明図、第２図及び第３ずは側方１ｌｉＩ
洩光フアイバーの電気的等価回路、第４図乃至第６図は
それぞれ側方漏洩光コアイノく−の実施例を示す図。
１・・・光源、２・・・側方漏洩光コアイノ＜−、３・
・・光入力端、４・・光出力端、５・・・受光器、６・
・・増幅・変換器、７・・・表示器、８・・空気、９・
・・液体、１０・・・空中漏洩、１１・・・液中漏洩。Figure 1 is a diagram explaining the principle, Figures 2 and 3 are lateral 1liI
4 to 6 are diagrams each showing an embodiment of a side leaking optical core. 1... Light source, 2... Lateral leakage light core ino<-, 3.
・・Optical input end, 4・・Optical output end, 5・・Receiver, 6・・
・・Amplifier/converter, 7・・Display device, 8・・Air, 9・
...liquid, 10...air leakage, 11...liquid leakage.
Claims (1)
部を浸すようになされた側方漏洩光ファイバーの一端か
ら光を投入し、他端から出力された光量を計測すること
によって、液位を計測するようにしたことを特長とする
側方漏洩光ファイバー式液位計。In an instrument that measures the level of a liquid, the liquid level is measured by injecting light from one end of a side-leaking optical fiber that is partially immersed in the liquid and measuring the amount of light output from the other end. A side leakage optical fiber type liquid level gauge.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24654190A JPH04125423A (en) | 1990-09-17 | 1990-09-17 | Lateral leakage optical fiber type level gage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24654190A JPH04125423A (en) | 1990-09-17 | 1990-09-17 | Lateral leakage optical fiber type level gage |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04125423A true JPH04125423A (en) | 1992-04-24 |
Family
ID=17149946
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24654190A Pending JPH04125423A (en) | 1990-09-17 | 1990-09-17 | Lateral leakage optical fiber type level gage |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04125423A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100607941B1 (en) * | 1999-11-10 | 2006-08-03 | 삼성전자주식회사 | Liquid level gauge |
| WO2008018281A1 (en) * | 2006-08-07 | 2008-02-14 | Hamamatsu Photonics K.K. | Mobile optical communication system and mobile optical communication method |
-
1990
- 1990-09-17 JP JP24654190A patent/JPH04125423A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100607941B1 (en) * | 1999-11-10 | 2006-08-03 | 삼성전자주식회사 | Liquid level gauge |
| WO2008018281A1 (en) * | 2006-08-07 | 2008-02-14 | Hamamatsu Photonics K.K. | Mobile optical communication system and mobile optical communication method |
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