JPH06249734A - Optical waveguide pressure sensor - Google Patents
Optical waveguide pressure sensorInfo
- Publication number
- JPH06249734A JPH06249734A JP4017193A JP4017193A JPH06249734A JP H06249734 A JPH06249734 A JP H06249734A JP 4017193 A JP4017193 A JP 4017193A JP 4017193 A JP4017193 A JP 4017193A JP H06249734 A JPH06249734 A JP H06249734A
- Authority
- JP
- Japan
- Prior art keywords
- optical waveguide
- laser
- diffraction grating
- change
- fluid transport
- 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.)
- Withdrawn
Links
Landscapes
- Measuring Fluid Pressure (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、化学プラント、製薬プ
ラントなどに用いられる流体輸送管や圧力容器などの管
壁圧力検出器として適用される光導波型圧力センサに関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide type pressure sensor applied as a pipe wall pressure detector for fluid transport pipes and pressure vessels used in chemical plants, pharmaceutical plants and the like.
【０００２】[0002]
【従来の技術】従来、流体輸送管や圧力容器などの管壁
に作用する圧力を検出する管壁圧力検出器として、図３
に示すようなものがある。2. Description of the Related Art Conventionally, as a pipe wall pressure detector for detecting a pressure acting on a pipe wall such as a fluid transport pipe or a pressure vessel, FIG.
There is something like.
【０００３】図３は、流体輸送管の管軸方向に垂直に切
断した断面図を示している。この場合、流体輸送管３１
内を流体３２が流れており、この流体輸送管３１内外の
圧力差により管壁に力が作用することで、管が膨脹ある
いは収縮する。FIG. 3 shows a cross-sectional view cut perpendicularly to the pipe axis direction of the fluid transport pipe. In this case, the fluid transport pipe 31
The fluid 32 is flowing inside, and a force acts on the pipe wall due to the pressure difference between the inside and outside of the fluid transport pipe 31, whereby the pipe expands or contracts.
【０００４】このような流体輸送管３１の外壁に歪みゲ
ージ３３を接着により固定し、流体輸送管３１の膨脹、
収縮に伴う管外周の長さの変化によりゲージ３３の長さ
を変化し、その歪みの抵抗値を変化する。A strain gauge 33 is fixed to the outer wall of the fluid transport pipe 31 by adhesion to expand the fluid transport pipe 31.
The length of the gauge 33 is changed by the change in the length of the outer circumference of the tube due to the contraction, and the resistance value of the strain is changed.
【０００５】そして、このゲージ３３での抵抗変化をホ
イートストンブリッチなどの抵抗測定回路３４を用いて
測定することにより、流体輸送管３１の管壁に作用した
圧力を間接的に知るようにしている。By measuring the resistance change at the gauge 33 by using a resistance measuring circuit 34 such as Wheatstone Blitch, the pressure acting on the pipe wall of the fluid transport pipe 31 is indirectly known.
【０００６】[0006]
【発明が解決しようとする課題】このようにした歪みゲ
ージを用いた管壁圧力検出器では、歪みゲージ３３の大
きさにより測定できる流体輸送管３１に制約が生じ、ま
た、ゲージ固定方法であるため流体３２の流れ方により
出力にバラツキが生じ易く、さらに、電気的測定のため
流体あるいは周囲雰囲気が可燃性、爆発性の場合には、
取扱いが危険であるなどの問題点がある。In the tube wall pressure detector using the strain gauge as described above, the measurable size of the strain gauge 33 limits the measurable fluid transport pipe 31, and the gauge fixing method is used. Therefore, the output tends to vary depending on the flow of the fluid 32. Further, when the fluid or the surrounding atmosphere is flammable or explosive for electrical measurement,
There are problems such as handling is dangerous.
【０００７】本発明は、上記事情に鑑みてなされたもの
で、適用範囲が広いとともに、正確な圧力検出が可能
で、しかも取扱いが簡単な光導波型圧力センサを提供す
ることを目的とする。The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical waveguide type pressure sensor which has a wide range of application, enables accurate pressure detection, and is easy to handle.
【０００８】[0008]
【課題を解決するための手段】本発明は、被検査部材の
表面に形成された回析格子と、前記被検査部材の表面に
前記回析格子を介して形成された薄膜による光導波路
と、この光導波路の一部に分散された利得波長帯域の広
いレーザ媒質とにより分布反射形レーザを構成し、この
分布反射形レーザを用いて前記被検査部材に対する圧力
変化を回析格子周期の変化に伴うレーザ発振波長の変化
により検出するように構成されている。According to the present invention, there is provided a diffraction grating formed on the surface of a member to be inspected, and an optical waveguide made of a thin film formed on the surface of the member to be inspected via the diffraction grating. A distributed reflection type laser is constituted by a laser medium having a wide gain wavelength band dispersed in a part of the optical waveguide, and the distributed reflection type laser is used to change the pressure change with respect to the member to be inspected into a change in the diffraction grating period. It is configured to detect by a change in the laser oscillation wavelength accompanying it.
【０００９】[0009]
【作用】この結果、本発明によれば、流体輸送管や圧力
容器などの被検査部材に対して作用する圧力変化を、被
検査部材壁面に形成した分布反射レーザを用い、その発
振波長の変化、すなわち出力光の波長変化を測定するこ
とにより格子周期の変化を壁壁の歪み量として検出する
ことができる。As a result, according to the present invention, the pressure change acting on the member to be inspected such as the fluid transportation pipe and the pressure vessel is changed by using the distributed reflection laser formed on the wall surface of the member to be inspected. That is, by measuring the wavelength change of the output light, the change of the grating period can be detected as the amount of distortion of the wall.
【００１０】[0010]
【実施例】以下、本発明の一実施例を図面に従い説明す
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
【００１１】図１は、同実施例の概略構成を示してい
る。図において、１１は流体輸送管で、この流体輸送管
１１は、その内部に流体１２が流れている。この場合、
流体輸送管１１は、流体１２の流れる部分を、その中心
軸からずらせて形成している。このような流体輸送管１
１の管壁の薄くなっている部分に回析格子１４を形成し
ている。FIG. 1 shows a schematic configuration of the same embodiment. In the figure, 11 is a fluid transport pipe, and a fluid 12 flows inside the fluid transport pipe 11. in this case,
The fluid transport pipe 11 is formed by displacing a portion where the fluid 12 flows from the central axis thereof. Such a fluid transport pipe 1
The diffraction grating 14 is formed in the thinned portion of the tube wall 1.
【００１２】ここで、流体輸送管１１は、その材質とし
て石英やガラスを想定しているが、ステンレスなどの金
属を用いる場合は、厚み１〜２μｍ程度のガラスやポリ
マなどの薄膜によるバッファ層を設け、その表面に格子
を形成するようになる。また、回析格子１４は、２次の
ブラッグ条件を満足するように格子周期を選ぶことによ
り、光導波を反射させる作用と導波路表面にレーザ光を
出力させる作用を有している。Here, the material of the fluid transport pipe 11 is assumed to be quartz or glass, but when a metal such as stainless steel is used, a buffer layer made of a thin film of glass or polymer having a thickness of about 1 to 2 μm is used. It is provided and the lattice is formed on the surface. The diffraction grating 14 has the function of reflecting the optical waveguide and the function of outputting the laser light to the waveguide surface by selecting the grating period so as to satisfy the second-order Bragg condition.
【００１３】また、流体輸送管１１の周面には、管材質
（あるいはバッファ層材質）の屈折率よりも屈折率の高
い透明な薄膜を厚み１μｍ程度に形成した光導波路１３
を設けている。On the peripheral surface of the fluid transport tube 11, a transparent thin film having a refractive index higher than that of the tube material (or buffer layer material) is formed to a thickness of about 1 μm.
Is provided.
【００１４】この光導波路１３は、その一部にレーザ色
素などの利得波長帯域の広いレーザ媒質１５を分散し、
回析格子１４、レーザ媒質１５、光導波路１３により分
布反射形レーザを構成している。図２は、このような流
体輸送管１１の管軸に直交する方向から見た図を示し、
図１と同一部分には同符号を付している。この場合、光
導波路１３は、横方向にも光を閉じ込めるため、管上に
形成した薄膜の一部を周囲の屈折率より１０-3〜１０-2
程度高く設定している。しかして、外部光源（図示せ
ず）から励起光１６が与えられ、レーザ媒体１５を励起
すると、光導波路１３中に蛍光１９が生じる。この蛍光
１９は、光導波路１３を伝搬する光波の波長のうち回析
格子１４の周期Λと等しくなったものが、強い反射光１
７として反射される。In this optical waveguide 13, a laser medium 15 having a wide gain wavelength band such as a laser dye is dispersed in a part thereof,
The diffraction grating 14, the laser medium 15, and the optical waveguide 13 form a distributed Bragg reflector laser. FIG. 2 shows a view seen from a direction orthogonal to the pipe axis of such a fluid transport pipe 11,
The same parts as those in FIG. 1 are designated by the same reference numerals. In this case, since the optical waveguide 13 also confines light in the lateral direction, a part of the thin film formed on the tube is 10 −3 to 10 −2 depending on the surrounding refractive index.
It is set a little higher. Then, when excitation light 16 is given from an external light source (not shown) to excite the laser medium 15, fluorescence 19 is generated in the optical waveguide 13. The fluorescence 19 has a wavelength of the light wave propagating through the optical waveguide 13 that is equal to the period Λ of the diffraction grating 14,
Reflected as 7.
【００１５】この反射光１７は、回析格子１４を挟んで
流体輸送管１１の周囲に形成された光導波路１３を往復
することで、管周の長さに応じた定存波が生じ共振状態
となる。つまり、実施例では、流体輸送管１１の円筒表
面上に光導波路１３を形成することにより従来は２個の
反射鏡より構成される共振器が１個の回析格子１４で構
成される。The reflected light 17 reciprocates through the optical waveguide 13 formed around the fluid transport pipe 11 with the diffraction grating 14 interposed therebetween, thereby generating a standing wave corresponding to the length of the pipe circumference and in a resonance state. Becomes That is, in the embodiment, by forming the optical waveguide 13 on the cylindrical surface of the fluid transport pipe 11, the resonator which is conventionally composed of two reflecting mirrors is composed of one diffraction grating 14.
【００１６】そして、共振した光は、レーザ媒体１５上
を規則正しい時間間隔で往復し、誘導放射光の量を増加
させる。そして、励起光強度、励起されたレーザ媒体１
５の非発光時間などの関係より導かれるある一定の条件
を満足することにより、誘導放射光の生成が削減する割
合が多くなり、レーザ発振が生じる。これにより分布反
射型のレーザ作用が実現される。Then, the resonated light reciprocates on the laser medium 15 at regular time intervals to increase the amount of stimulated emission light. Then, the excitation light intensity and the excited laser medium 1
By satisfying a certain condition derived from the relationship such as the non-emission time of No. 5, the ratio of generation of stimulated emission light is reduced and laser oscillation occurs. Thereby, a distributed reflection type laser action is realized.
【００１７】この場合のレーザの発振波長は、回析格子
１４の反射波長と共振器長によって決まるもので、定在
波条件を満たす共振器の長さはとびとびの値となるが、
その間隔が回析格子１４の反射波長の変化量より十分に
小さくしておくことにより、発振波長は回析格子１４の
周期Λに強く支配されることになる。The oscillation wavelength of the laser in this case is determined by the reflection wavelength of the diffraction grating 14 and the resonator length, and the length of the resonator satisfying the standing wave is a discrete value.
By setting the spacing sufficiently smaller than the amount of change in the reflection wavelength of the diffraction grating 14, the oscillation wavelength is strongly controlled by the period Λ of the diffraction grating 14.
【００１８】このような条件を満たす共振器構造とする
ことにより、図１に示したように流体輸送管１１の管壁
の肉厚が最も薄い部分に回析格子１４を形成しているた
め流体輸送管１１内外の圧力差により生じる膨脹、収縮
が回析格子１４部分に有効に生じ圧力変化が発振波長の
変化として取り出すことができることになる。ここで、
回析格子１４は２次のブラッグ条件を満足する格子周期
を持つため、導波光を反射させる以外に一部導波路表面
に垂直方向に回析波が生じる。By providing the resonator structure satisfying such conditions, the diffraction grating 14 is formed in the thinnest portion of the wall of the fluid transport pipe 11 as shown in FIG. Expansion and contraction caused by the pressure difference between the inside and outside of the transport pipe 11 effectively occur in the diffraction grating 14 portion, and the pressure change can be taken out as the change of the oscillation wavelength. here,
Since the diffraction grating 14 has a grating period that satisfies the second-order Bragg condition, a diffraction wave is generated in a direction perpendicular to the waveguide surface in addition to reflecting the guided light.
【００１９】これにより、導波路内で生じたレーザ光を
回析格子１４から取り出すことが可能となり、この出力
光１８の波長変化を測定することにより、格子周期の変
化、すなわち流体輸送管１１管壁の歪み量を高精度に検
出することができることになる。This makes it possible to extract the laser light generated in the waveguide from the diffraction grating 14, and by measuring the wavelength change of the output light 18, the change of the grating period, that is, the fluid transport pipe 11 The amount of strain on the wall can be detected with high accuracy.
【００２０】ちなみに、具体例として、レーザ媒質１５
にキトンレッド６２０を用い、光導波路１３を膜厚１．
６μｍの石英によるバッファ層と膜厚１．０μｍのポリ
メタクリル酸メチル薄膜で構成した場合を説明する。Incidentally, as a specific example, the laser medium 15
Kiton Red 620 is used for the optical waveguide 13 and the film thickness is 1.
A case will be described in which the buffer layer is made of quartz having a thickness of 6 μm and the polymethylmethacrylate thin film having a thickness of 1.0 μm is used.
【００２１】この場合、周期４２０ｎｍの回析格子１４
を用いると、真空中の波長６２０ｎｍの導波光に対して
２次のブラッグ条件を満足する。そして、この構成を外
周の中心軸と内面の中心軸を１．５ｃｍずらしている内
径２５ｃｍ、外径３０ｃｍで面荒さ０．３μｍ以下に鏡
面研磨した流体輸送管１１をなすステンレス管表面に形
成する。In this case, the diffraction grating 14 having a period of 420 nm
Is used, the second-order Bragg condition is satisfied for the guided light having a wavelength of 620 nm in vacuum. Then, this structure is formed on the surface of the stainless steel pipe forming the fluid transport pipe 11 which is mirror-polished to have an inner diameter of 25 cm, an outer diameter of 30 cm, and a surface roughness of 0.3 μm or less, in which the center axis of the outer periphery and the center axis of the inner surface are displaced by 1.5 cm. .
【００２２】まず、管表面に石英膜を真空蒸着法により
形成し、回析格子１４を管壁厚さが最小になる位置に幅
５ｍｍ長さ１ｃｍにわたり干渉露光法とイオンビームエ
ッチング法により格子の凹凸部の高さが０．０２μｍと
なるように形成する。そして、その表面に垂直引上げ法
により色素（キトンレッド６２０）を分散させたポリメ
タクリル酸メチル薄膜を形成することによって光導波路
１３を形成する。First, a quartz film is formed on the surface of the tube by a vacuum vapor deposition method, and the diffraction grating 14 is formed at a position where the tube wall thickness is minimized over a width of 5 mm and a length of 1 cm by an interference exposure method and an ion beam etching method. It is formed so that the height of the uneven portion is 0.02 μm. Then, an optical waveguide 13 is formed by forming a polymethylmethacrylate thin film in which a dye (Kitton Red 620) is dispersed on the surface by a vertical pulling method.
【００２３】そして、このような光導波路１３の一部分
をＮｄ：ＹＡＧレーザの第２高調波を用いて励起するこ
とにより、波長６２０ｍｍ，線幅０．１ｍｍのレーザ発
振が生じる。すると、管内の圧力変化に応じて回析格子
１４に伸びが生じ、発振波長が長波長側に圧力変化率に
比例してシフトする。例えば１０ｋｇ／ｃｍ2 の管内圧
力が１０．１ｋｇ／ｃｍ2 に変動した場合、その波長変
化は６．２ｎｍとなる。これにより流体輸送管１１の管
壁の歪み量を検出できることになる。By exciting a part of the optical waveguide 13 with the second harmonic of the Nd: YAG laser, laser oscillation having a wavelength of 620 mm and a line width of 0.1 mm occurs. Then, the diffraction grating 14 expands according to the pressure change in the tube, and the oscillation wavelength shifts to the long wavelength side in proportion to the pressure change rate. For example, 10 kg / cm 2 Internal pressure of 10.1kg / cm 2 When it changes to, the wavelength change becomes 6.2 nm. This makes it possible to detect the amount of strain on the wall of the fluid transport pipe 11.
【００２４】なお、本発明は上記実施例にのみ限定され
ず、要旨を変更しない範囲で適宜変形して実施できる。
上述した実施例でき、流体輸送管の管壁の歪みを検出す
る場合を述べたが、モータシャフトなどの回転体主軸な
どに適用することにより主軸のねじれなどの歪みセンサ
としての応用が可能である。The present invention is not limited to the above-mentioned embodiments, and can be carried out by appropriately modifying it without departing from the scope of the invention.
Although the above-described embodiment can be performed and the case where the strain of the pipe wall of the fluid transport pipe is detected has been described, it can be applied as a strain sensor such as a twist of the main shaft by applying the main shaft of a rotating body such as a motor shaft. .
【００２５】[0025]
【発明の効果】このように本発明によれば円筒断面を有
する流体輸送管や圧力容器などの被検査部材の壁面に作
用する圧力を壁面に形成した分布反射レーザを用い、そ
の発振波長の変化より検出するようにしたので、例えば
流体輸送管の場合には、予めセンサを構成した管を、そ
の両端に接続ジョイントを介して輸送管系統の必要な箇
所に取り付けるだけで用いることができ、その使用範囲
が制限されることなく広く使用することができる。ま
た、分布反射レーザを用いることで正確な圧力検出が可
能で、しかも光を用いることで周囲雰囲気が可燃性、爆
発性の場合にも使用できるなど、取扱いも簡単にできる
など産業上利用価値が大である。As described above, according to the present invention, the distributed reflection laser in which the pressure acting on the wall surface of the member to be inspected such as the fluid transport pipe or the pressure vessel having the cylindrical cross section is formed on the wall surface, and the oscillation wavelength thereof is changed Since it is made to detect more, for example, in the case of a fluid transport pipe, it is possible to use a pipe in which a sensor is configured in advance by simply attaching it to a necessary position of the transport pipe system through connection joints at both ends thereof. It can be widely used without limiting the range of use. In addition, the distributed reflection laser can be used for accurate pressure detection, and the use of light can be used when the surrounding atmosphere is flammable or explosive. Is large.
【図１】本発明の一実施例の概略構成を示す図。FIG. 1 is a diagram showing a schematic configuration of an embodiment of the present invention.
【図２】本発明の一実施例の概略構成を示す図。FIG. 2 is a diagram showing a schematic configuration of an embodiment of the present invention.
【図３】従来の管壁圧力検出器の一例を示す図。FIG. 3 is a diagram showing an example of a conventional tube wall pressure detector.
１１…流体輸送管、１２…流体、１３…光導波路、１４
…回析格子、１５…レーザ媒質、１６…励起光、１７…
反射光、１８…出力光、１９…蛍光。11 ... Fluid transport pipe, 12 ... Fluid, 13 ... Optical waveguide, 14
... Diffraction grating, 15 ... Laser medium, 16 ... Excitation light, 17 ...
Reflected light, 18 ... Output light, 19 ... Fluorescence.
Claims (1)
と、 前記被検査部材の表面に前記回析格子を介して形成され
た薄膜による光導波路と、 この光導波路の一部に分散された利得波長帯域の広いレ
ーザ媒質とにより分布反射形レーザを構成し、 該分布反射形レーザを用いて前記被検査部材に対する圧
力変化を回析格子周期の変化に伴うレーザ発振波長の変
化により検出することを特徴とする光導波型圧力セン
サ。1. A diffraction grating formed on the surface of a member to be inspected, an optical waveguide made of a thin film formed on the surface of the member to be inspected via the diffraction grating, and dispersed in a part of this optical waveguide. And a laser medium having a wide gain wavelength band are used to form a distributed reflection laser, and the distributed reflection laser is used to detect a pressure change with respect to the member to be inspected by a change in laser oscillation wavelength accompanying a change in diffraction grating period. An optical waveguide type pressure sensor characterized in that.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4017193A JPH06249734A (en) | 1993-03-01 | 1993-03-01 | Optical waveguide pressure sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4017193A JPH06249734A (en) | 1993-03-01 | 1993-03-01 | Optical waveguide pressure sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06249734A true JPH06249734A (en) | 1994-09-09 |
Family
ID=12573326
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4017193A Withdrawn JPH06249734A (en) | 1993-03-01 | 1993-03-01 | Optical waveguide pressure sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06249734A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102013107276A1 (en) | 2012-07-11 | 2013-10-02 | Lios Technology Gmbh | Device for distributed optical pressure measurement in borehole, comprises optical light guide with core, which guides light from light source along measurement path, and casing that reacts to pressure change with elongation or contraction |
-
1993
- 1993-03-01 JP JP4017193A patent/JPH06249734A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102013107276A1 (en) | 2012-07-11 | 2013-10-02 | Lios Technology Gmbh | Device for distributed optical pressure measurement in borehole, comprises optical light guide with core, which guides light from light source along measurement path, and casing that reacts to pressure change with elongation or contraction |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20000509 |