JPH11201841A - Pressure change measuring device - Google Patents
Pressure change measuring deviceInfo
- Publication number
- JPH11201841A JPH11201841A JP1765498A JP1765498A JPH11201841A JP H11201841 A JPH11201841 A JP H11201841A JP 1765498 A JP1765498 A JP 1765498A JP 1765498 A JP1765498 A JP 1765498A JP H11201841 A JPH11201841 A JP H11201841A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- container
- outside
- change
- measuring device
- 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
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
- G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
- G01L11/025—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means using a pressure-sensitive optical fibre
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、基準部と感圧部から構
成し海底に沈設して水圧を計測し津波を計測するのに好
適な圧力変化計測装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure change measuring device which comprises a reference portion and a pressure-sensitive portion, and which is disposed on the seabed to measure a water pressure and to measure a tsunami.
【0002】[0002]
【従来の技術】海域に大地震が発生した場合、極短時間
のうちに沿岸部での津波の高さを推定し、関係地域に伝
達することは、防災上極めて重要である。気象庁の津波
警報システムでは、地震発生後にその位置や大きさから
の経験式に基づいて波高を予測している。このような予
測システムの上に津波による海面上昇の実測値を付加す
れば、予報の精度が格段に向上することになる。2. Description of the Related Art When a large earthquake occurs in a sea area, it is extremely important for disaster prevention to estimate the height of a tsunami in a coastal area within a very short time and to transmit the height to a related area. The tsunami warning system of the Japan Meteorological Agency predicts the wave height after an earthquake occurs based on empirical formulas based on the position and size. If the actual value of the sea level rise due to the tsunami is added to such a prediction system, the accuracy of the forecast will be significantly improved.
【0003】従来、津波計としては、例えば気象庁のケ
ーブル式海底地震常時観測システムで利用しているもの
がある。これらは水晶振動式の水圧変化計であり、津波
計測上、圧力変化検出のためには十分な分解能を有して
いるが、周辺海水温の変化の影響を受けやすく、現実に
は純粋な圧力変化だけを検出する上で困難がある。ま
た、搬送装置等が必要となり、単独で使用するときは高
価なものとなる。そこで、このような従来の津波計測の
手段に代わるものとして、本発明者が既に提案している
レーザひずみ計(特許第2560260号)の地中部分
を水圧計として利用し、光ファイバで陸上までデータ伝
送する方式の津波波高検知システムが考えられる。この
システムによれば、高精度、低価格、低維持費のシステ
ムが実現できる。以下に本発明者が既に提案しているレ
ーザひずみ計について説明する。Conventionally, as a tsunami meter, there is a tsunami meter which is used, for example, by a cable type ocean bottom seismic constant observation system of the Japan Meteorological Agency. These are crystal vibration type water pressure change meters, which have sufficient resolution to detect pressure changes in tsunami measurement, but are susceptible to changes in the surrounding seawater temperature, and in reality, pure pressure There is a difficulty in detecting only the change. Further, a transport device or the like is required, and when used alone, it becomes expensive. Therefore, as an alternative to such conventional tsunami measurement means, the underground portion of a laser strain meter (Japanese Patent No. 2560260) already proposed by the present inventor is used as a water pressure gauge, and the optical fiber is used to reach the land. A tsunami wave height detection system that uses data transmission is conceivable. According to this system, a system with high accuracy, low price, and low maintenance cost can be realized. Hereinafter, a laser strain meter that the present inventor has already proposed will be described.
【0004】図4はレーザひずみ計の構成例を示す図、
図5はレーザひずみ計の平面配置例を示す図である。図
において、1は円筒容器、、2はシール部、3は光ファ
イバ、4と9はコリメータ、5と10はレンズ、6と1
1は直角プリズム、7と13は凹面鏡ホルダ、8と12
は凹面鏡を示す。FIG. 4 is a diagram showing a configuration example of a laser strain gauge.
FIG. 5 is a diagram showing an example of a plane arrangement of the laser strain gauge. In the figure, 1 is a cylindrical container, 2 is a seal portion, 3 is an optical fiber, 4 and 9 are collimators, 5 and 10 are lenses, 6 and 1
1 is a right angle prism, 7 and 13 are concave mirror holders, 8 and 12
Indicates a concave mirror.
【0005】図4において、円筒容器1は、例えば金属
製やセラミック製等、微小なひずみ変化を口径の変化と
して計測できる耐食性のある耐圧容器であればよい。そ
して、円筒容器1の中は、媒体の温度変化による影響を
排除するため、真空状態にするが、地中に埋設する場合
には、比較的温度が安定しているので、不活性ガスを充
填した状態に維持してもよい。[0005] In FIG. 4, a cylindrical container 1 may be a corrosion-resistant pressure-resistant container made of metal, ceramic, or the like, and capable of measuring a small change in strain as a change in diameter. The inside of the cylindrical container 1 is evacuated in order to eliminate the influence of the temperature change of the medium, but when buried in the ground, the temperature is relatively stable, so that the container is filled with an inert gas. May be maintained.
【0006】基準用共振器は、凹面鏡ホルダ13により
一定間隔に固定されてセンサ用共振器の近傍に設置され
た対の凹面鏡12とコリメータ9とレンズ10と直角プ
リズム11とからなり、光ファイバ3からコリメータ9
を通してレーザ光を入射させるようにした多重反射のフ
ァブリペロー型干渉計を用いたものである。これに対し
てセンサ用共振器は、凹面鏡ホルダ7により円筒容器1
の内壁に直径方向が光軸になるように固定された対の凹
面鏡8とコリメータ4とレンズ5と直角プリズム6とか
らなり、光ファイバ3からコリメータ4を通してレーザ
光を入射させるようにした多重反射のファブリペロー型
干渉計を用いたものである。そして、対の凹面鏡8の光
軸が互いに異なる方向になるようにして複数のセンサ用
共振器が配置される。The reference resonator is composed of a pair of concave mirrors 12, a collimator 9, a lens 10, and a right-angle prism 11, which are fixed at fixed intervals by a concave mirror holder 13 and are installed near the sensor resonator. From collimator 9
And a multiple reflection Fabry-Perot interferometer in which a laser beam is made to enter through the laser beam. On the other hand, the resonator for sensor uses the concave mirror holder 7 for the cylindrical container 1.
A plurality of concave mirrors 8, a collimator 4, a lens 5, and a right-angle prism 6, which are fixed to the inner wall of the optical fiber so that the diameter direction is the optical axis, so that a laser beam is incident from the optical fiber 3 through the collimator 4. Using a Fabry-Perot interferometer. Then, a plurality of sensor resonators are arranged such that the optical axes of the pair of concave mirrors 8 are different from each other.
【0007】各共振器を構成する凹面鏡の配置例を示し
たのが図5であり、凹面鏡8−1と8−1′、8−2と
8−2′、8−3と8−3′の対をセンサ用共振器に用
いそれらの光軸が互いに120°の方向をなすように円
筒容器1の内壁に固定することによって、同一平面上に
配置することができる。また、凹面鏡9と9′の対を基
準用共振器に用い、これをセンサ用共振器の凹面鏡の間
隙に配置して一定間隔に固定することによって、やはり
同一平面上に配置することができる。FIG. 5 shows an example of the arrangement of concave mirrors constituting each resonator. The concave mirrors 8-1 and 8-1 ', 8-2 and 8-2', 8-3 and 8-3 'are shown. Can be arranged on the same plane by fixing the pair to the inner wall of the cylindrical container 1 so that their optical axes are oriented at 120 ° to each other. Also, by using a pair of concave mirrors 9 and 9 'as a reference resonator, and arranging them in the gap between the concave mirrors of the sensor resonator and fixing them at a constant interval, the mirrors can also be arranged on the same plane.
【0008】対をなす凹面鏡8、12には、特に反射率
の高いものを用い、その固定については、平行度の確保
と光軸の一致について、最大限の注意が払われる。凹面
鏡8および直角プリズム6は、凹面鏡ホルダ7により円
筒容器1の内壁にしっかりと取り付けられる。基準用共
振器では、凹面鏡ホルダ13に熱膨張率の小さい部材を
用い、円筒容器1の変形が対の凹面鏡12の間の距離に
影響を与えないように配置することは勿論である。As the pair of concave mirrors 8 and 12, mirrors having particularly high reflectivity are used. For fixing the mirrors, maximum attention is paid to securing parallelism and matching optical axes. The concave mirror 8 and the right-angle prism 6 are firmly attached to the inner wall of the cylindrical container 1 by the concave mirror holder 7. In the reference resonator, a member having a small coefficient of thermal expansion is used for the concave mirror holder 13 and, of course, the concave mirror holder 13 is arranged so that the deformation of the cylindrical container 1 does not affect the distance between the pair of concave mirrors 12.
【0009】このレーザひずみ計では、地上にあるレー
ザ発振器からの光が円筒容器1の外側からシール部2を
通して光ファイバ3により内部に導かれる。そして、コ
リメータ4、9で平行にした光束をレンズ5、10で共
振器(キャビティ)の中に焦点を結ぶようにし、プリズ
ム6、11で反射させて凹面鏡8、12の背後から共振
器内部に入射させる。この共振器内に導かれた光は、凹
面鏡8、12の間の距離に応じた周波数で共振をする。In this laser strain gauge, light from a laser oscillator on the ground is guided from the outside of the cylindrical container 1 through the seal portion 2 to the inside by the optical fiber 3. Then, the light beams collimated by the collimators 4 and 9 are focused into the resonator (cavity) by the lenses 5 and 10 and are reflected by the prisms 6 and 11 to be reflected from the concave mirrors 8 and 12 into the resonator. Make it incident. The light guided into the resonator resonates at a frequency corresponding to the distance between the concave mirrors 8 and 12.
【0010】図6はレーザひずみ計の地上側信号処理系
の構成例を示す図であり、21、24、30はカップ
ラ、22、28、31、32はアイソレータ、23、3
4はレーザ発振器、25は高速フォトデテクタ、26は
カウンタ、27と35はフィードバック回路、29と3
3は低速フォトデテクタを示す。FIG. 6 is a diagram showing a configuration example of a signal processing system on the ground side of a laser strain meter, wherein 21, 24, and 30 are couplers, 22, 28, 31, and 32 are isolators, and 23 and 3 are shown.
4 is a laser oscillator, 25 is a high-speed photodetector, 26 is a counter, 27 and 35 are feedback circuits, 29 and 3
Reference numeral 3 denotes a low-speed photodetector.
【0011】各共振器には、図4に示すように一対の光
ファイバ3が導かれ、各共振器の対をなす2枚の凹面鏡
8、12に1本ずつ光学的に接続される。そのうち、一
方の光ファイバ3には、図6に示すような外部にあるレ
ーザ発振器23、34からのレーザ光が導かれ、他方の
光ファイバ3を通して共振器内の光がフィードバック回
路27、35に導かれる。アイソレータ22、31は、
地中部の共振器からの逆向きの光が再びレーザ発振器2
3、34に入るのを防ぐためのものであり、アイソレー
タ28、32は、低速フォトデテクタ29と33からの
反射光が地中共振器に入るのを防ぐためのものである。
そして、このフィードバック回路27、35により、レ
ーザ発振器23、34の共振周波数が共振器の共振周波
数と一致するようにレーザ発振器23、34のピエゾ素
子を伸縮してレーザ発振器23、34の凹面鏡の間隔を
制御している。As shown in FIG. 4, a pair of optical fibers 3 are guided to each resonator, and are optically connected one by one to two concave mirrors 8 and 12 forming a pair of each resonator. The laser light from the external laser oscillators 23 and 34 as shown in FIG. 6 is guided to one optical fiber 3, and the light in the resonator is fed to the feedback circuits 27 and 35 through the other optical fiber 3. Be guided. The isolators 22 and 31 are
The reverse light from the underground resonator is again emitted by the laser oscillator 2
The isolators 28 and 32 prevent reflected light from the low-speed photodetectors 29 and 33 from entering the underground resonator.
The feedback circuits 27 and 35 expand and contract the piezo elements of the laser oscillators 23 and 34 so that the resonance frequencies of the laser oscillators 23 and 34 match the resonance frequency of the resonators. Is controlling.
【0012】このようにして制御されレーザ発振器2
3、34から共振器内に導かれたレーザ光は、カップラ
21、30から計測用として取り込まれる。そして、カ
ップラ24で、これらそれぞれにカップラ30を通して
取り込まれたセンサ用共振器の光とカップラ21を通し
て取り込まれた基準用型共振器の光を足し合わせてフォ
トデテクタ25に作用させ、各センサ用共振器と基準用
型共振器との共振周波数の差をカウンタ26で検出す
る。したがって、共振周波数の差が3つ得られるので、
これらを利用すると、次のようにひずみ変化が得られ
る。The laser oscillator 2 controlled as described above
The laser light guided into the resonator from 3 and 34 is taken in from the couplers 21 and 30 for measurement. Then, the coupler 24 adds the light of the sensor resonator taken in through the coupler 30 and the light of the reference type resonator taken in through the coupler 21 to the photodetector 25, and causes the photodetector 25 to operate. The difference between the resonance frequencies of the device and the reference type resonator is detected by the counter 26. Therefore, three resonance frequency differences are obtained,
When these are used, a strain change is obtained as follows.
【0013】3つの共振周波数の差をΔω1 、Δω2 、
Δω3 とするとThe difference between the three resonance frequencies is represented by Δω 1 , Δω 2 ,
If Δω 3
【0014】[0014]
【数1】Δω1 =ω1 −ωref Δω2 =ω2 −ωref Δω3 =ω3 −ωref ここでω1 、ω2 、ω3 およびωref は、3つのセンサ
用共振器および基準用共振器の共振周波数であり、ω1
≒ω2 ≒ω3 ≒ωref であることを考えるとΔω 1 = ω 1 −ω ref Δω 2 = ω 2 −ω ref Δω 3 = ω 3 −ω ref where ω 1 , ω 2 , ω 3 and ω ref are three sensor resonators and The resonance frequency of the reference resonator, ω 1
Given that ≒ ω 2 ≒ ω 3 ≒ ω ref
【0015】[0015]
【数2】Δω1 /ω1 =Δω1 /ωref =−Δd1 /d
→Δd1 =−(Δω1 /ωref )d ここでΔd1 はセンサ方向の直径の伸縮量である。同様
に## EQU2 ## Δω 1 / ω 1 = Δω 1 / ω ref = −Δd 1 / d
→ Δd 1 = − (Δω 1 / ω ref ) d Here, Δd 1 is the amount of expansion and contraction of the diameter in the sensor direction. Likewise
【0016】[0016]
【数3】Δd2 =−(Δω2 /ωref )d Δd3 =−(Δω3 /ωref )d このようにして独立した3直径の変化量が得られるの
で、既に確立されている孔径変化によるひずみ測定理論
に基づき、ひずみ変化の3成分を求めることができる。## EQU3 ## Δd 2 = − (Δω 2 / ω ref ) d Δd 3 = − (Δω 3 / ω ref ) d In this manner, three independent diameter variations can be obtained. The three components of strain change can be determined based on the theory of strain measurement due to change.
【0017】[0017]
【発明が解決しようとする課題】図7はレーザひずみ計
の津波計への利用例を示す図である。通常、沖合100
kmから沿岸まで津波が到達するのに10〜20分程度
かかるので、図7に示すようにレーザひずみ計の地中部
をレーザ水圧計41として例えば沖合100kmの海底
に沈設して、このレーザ水圧計41と地上のレーザ装置
43との間を光ファイバ海底ケーブル42により接続す
ることにより、到達10〜20分前に予測が可能な津波
計として利用することができる。FIG. 7 is a diagram showing an example of using a laser strain gauge for a tsunami meter. Usually offshore 100
Since it takes about 10 to 20 minutes for the tsunami to reach the coast from km, as shown in FIG. 7, the underground part of the laser strain gauge is laid as a laser water pressure gauge 41 on the sea floor 100 km offshore, for example. By connecting the optical fiber submarine cable 42 between the laser device 41 and the ground-based laser device 43, the tsunami meter can be used as a tsunami meter that can predict 10 to 20 minutes before arrival.
【0018】しかし、上記のレーザひずみ計の場合、例
えば地中に埋め込み地殻の微小なひずみ変化を口径の変
化として計測するのであれば、ボアホール内の温度は非
常に安定しているので問題ないが、これをそのまま津波
計として利用すると海底水流等による水温の変化により
影響を受けるため問題が生じてくる。However, in the case of the above laser strain meter, if the minute strain change of the crust buried in the ground is measured as a change in diameter, there is no problem because the temperature in the borehole is very stable. However, if this is used as it is as a tsunami meter, it will be affected by changes in water temperature due to sea bottom water currents and the like, causing a problem.
【0019】すなわち、上記のレーザひずみ計を津波計
として海底に設置した場合、海底水流等により温度環境
が急変することがあると、この温度変化による円筒容器
の熱膨張あるいは収縮による変形が水位変化による変形
と同じ程度になる可能性がある。また、水温変化があっ
てもセンサ共振器の温度変化と基準共振器の温度変化の
両者が同期していれば問題はないが、両者にズレが生じ
るためその影響が無視できなくなる。That is, when the above laser strain gauge is installed on the sea floor as a tsunami meter, if the temperature environment changes suddenly due to the sea bottom water flow or the like, the deformation due to the thermal expansion or contraction of the cylindrical container due to the temperature change is caused by the water level change. To the same degree as deformation due to Further, even if there is a change in the water temperature, there is no problem if both the temperature change of the sensor resonator and the temperature change of the reference resonator are synchronized.
【0020】[0020]
【課題を解決するための手段】本発明は、上記課題を解
決するものであって、海底水流など外部の流動する媒体
による温度環境の急変に伴う影響を排除するものであ
る。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to eliminate an influence caused by a sudden change in a temperature environment caused by an external flowing medium such as a seabed water stream.
【0021】そのために本発明は、圧力変化を検出する
感圧部と該感圧部に対して基準の信号を発生する基準部
とを有する圧力変化計測装置において、感圧部及び基準
部に外側容器を設けると共に、感圧部における外側容器
には、外部と連通する小孔を設けて該小孔を通して外部
の圧力を伝達し、基準部における外側容器は、内側容器
との間に外部の媒体を導入して封入するように構成した
ことを特徴とするものである。また、円筒形の外側容器
と、該外側容器と同軸の円筒形内側容器からなり、内側
容器に光共振器を取り付け内側容器の変形量を計測する
ことを特徴とするものである。For this purpose, the present invention relates to a pressure change measuring apparatus having a pressure-sensitive portion for detecting a pressure change and a reference portion for generating a reference signal for the pressure-sensitive portion. A container is provided, and a small hole communicating with the outside is provided in the outer container in the pressure-sensitive portion, and external pressure is transmitted through the small hole. Is introduced and enclosed. Further, the present invention is characterized by comprising a cylindrical outer container and a cylindrical inner container coaxial with the outer container, wherein an optical resonator is attached to the inner container and the amount of deformation of the inner container is measured.
【0022】[0022]
【発明の実施の形態】以下、本発明の実施の形態を図面
を参照しつつ説明する。図1は本発明に係る圧力変化計
測装置の実施の形態を示す図であり、51、67は外側
円筒容器、52、53は内側円筒容器、54は内蓋、5
5は光ファイバ、56はセンサ用共振器、57は圧力伝
達用小孔、58は外部連通部、61はケーブル接続部、
62はシール部、63は基準用共振器、64は封入部、
65は封入用小孔、66は封入用栓を示す。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an embodiment of a pressure change measuring device according to the present invention, in which 51 and 67 are outer cylindrical containers, 52 and 53 are inner cylindrical containers, 54 is an inner lid,
5 is an optical fiber, 56 is a sensor resonator, 57 is a pressure transmission small hole, 58 is an external communication part, 61 is a cable connection part,
62 is a seal portion, 63 is a reference resonator, 64 is a sealed portion,
Reference numeral 65 denotes a small hole for encapsulation, and 66 denotes a plug for encapsulation.
【0023】図1において、本発明に係る圧力変化計測
装置は、連結部と該連結部を挟んだ圧力変化を検出する
感圧部と感圧部に対して基準の信号を発生する基準部と
からなり、感圧部と基準部は、外側円筒容器51、67
と同軸にそれぞれ内側円筒容器52、53を有してい
る。内側円筒容器52、53は、連結部側がそれぞれ内
蓋54で塞がれて外側円筒容器51、67に固定され、
内側円筒容器52、53の周りの外側円筒容器51、6
7との間に外部連通部58又は封入部64を設けてい
る。外部連通部58は、感圧部における外側円筒容器5
1に少なくとも1つの圧力伝達用小孔57を設け、外側
円筒容器51の外部と連通する空間を形成し、その内側
円筒容器52の中に反射鏡、プリズム、コリメータを有
するセンサ用共振器56を設けている。封入部64は、
基準部における外側円筒容器67に少なくとも1つの封
入用小孔65を設け、外部の媒体(海水やガス等)を導
入して封入用栓66で封入することにより、外側円筒容
器67の外部と遮断した空間を形成し、その内側円筒容
器53の中に反射鏡、プリズム、コリメータを有する基
準用共振器63を設けている。In FIG. 1, a pressure change measuring device according to the present invention comprises a connecting portion, a pressure-sensitive portion for detecting a pressure change across the connecting portion, and a reference portion for generating a reference signal for the pressure-sensitive portion. And the pressure-sensitive part and the reference part are the outer cylindrical containers 51, 67
And inner cylindrical containers 52 and 53, respectively. The inner cylindrical containers 52 and 53 are fixed to the outer cylindrical containers 51 and 67, respectively, with the connection side closed by the inner lid 54,
Outer cylindrical containers 51, 6 around inner cylindrical containers 52, 53
7, an external communication portion 58 or a sealing portion 64 is provided. The external communication part 58 is connected to the outer cylindrical container 5 in the pressure sensing part.
At least one pressure transmitting small hole 57 is provided in 1 to form a space communicating with the outside of the outer cylindrical container 51, and a sensor resonator 56 having a reflecting mirror, a prism, and a collimator is provided in the inner cylindrical container 52. Provided. The sealing portion 64
At least one small hole 65 for sealing is provided in the outer cylindrical container 67 in the reference portion, and an external medium (seawater, gas, etc.) is introduced and sealed with the sealing plug 66 to shut off the outside of the outer cylindrical container 67. A reference resonator 63 having a reflecting mirror, a prism, and a collimator is provided in the inner cylindrical container 53.
【0024】外部から感圧部のセンサ用共振器56及び
基準部の基準用共振器63に接続する光ファイバ55
は、それぞれ内側円筒容器52、53の内蓋54のシー
ル部62を通して連結部に導かれ、この連結部からケー
ブル接続部61を通して外部に引き出される。なお、連
結部、感圧部の内側円筒容器52の中及び基準部の内側
円筒容器53の中には、例えば不活性ガスを封入する。Optical fiber 55 externally connected to the sensor resonator 56 of the pressure sensitive section and the reference resonator 63 of the reference section.
Is guided to the connecting portion through the sealing portion 62 of the inner lid 54 of the inner cylindrical containers 52 and 53, and is drawn out of the connecting portion through the cable connecting portion 61 to the outside. In addition, an inert gas, for example, is sealed in the inner cylindrical container 52 of the connecting portion and the pressure-sensitive portion and in the inner cylindrical container 53 of the reference portion.
【0025】次に、上記のように構成した本発明に係る
圧力変化計測装置を、例えば海底に沈設して津波計とし
て使用する場合について説明する。まず、設置に際して
基準部の封入用栓66を外して封入用小孔65から海水
を封入部64に導入した後、封入用小孔65を封入用栓
66で塞ぐことにより、封入部64に海水を封入する。
津波計を海底に沈設した場合、基準部における外側から
の圧力変化は、大部分が外側容器に受け止められるた
め、内側容器外側の圧力変化は、たいへん小さなものと
なる。このことにより、基準部の内側容器53は、外側
円筒容器67の外部にかかる圧力変化の影響をほとんど
受けないか、あるいは受けるとしてもたいへん小さなも
のとなる。一方、感圧部における内側円筒容器52は、
その外側が圧力伝達用小孔57により外側円筒容器51
の外部と連通して海水が満たされた外部連通部58で覆
われているため、外部の圧力変化に応じて円筒は変形
し、このときの直径変化をセンサ用共振器56により検
出することができる。Next, a description will be given of a case where the pressure change measuring device according to the present invention configured as described above is used, for example, as a tsunami meter by being settled on the sea floor. First, at the time of installation, the sealing plug 66 of the reference portion is removed and seawater is introduced into the sealing portion 64 from the sealing hole 65, and then the sealing hole 65 is closed with the sealing plug 66, so that the seawater is filled in the sealing portion 64. Is enclosed.
When the tsunami meter is submerged on the sea floor, most of the pressure change from the outside at the reference part is received by the outer container, and the pressure change outside the inner container is very small. As a result, the inner container 53 of the reference portion is hardly affected by the pressure change applied to the outside of the outer cylindrical container 67, or is very small at all. On the other hand, the inner cylindrical container 52 in the pressure-sensitive portion
The outside of the outer cylindrical container 51 is formed by a pressure transmitting small hole 57.
Since the cylinder is deformed in response to an external pressure change, the diameter change at this time can be detected by the sensor resonator 56 because the external communication portion 58 is filled with seawater in communication with the outside. it can.
【0026】感圧部の内外円筒間の海水は、小孔で外部
に通じているとはいうものの、孔の径が小さいことによ
り内外海水の交換はたいへん小さい。また、小孔中の水
の熱伝導度は金属よりはるかに小さい。また、感圧部、
基準部とも幾何学的に同じ形状で、感圧部内側円筒に接
する海水と基準部内外円筒間に封入された海水が物性的
にほぼ同じものであることを考えると、外部温度の変動
による内側円筒の温度による膨張あるいは収縮の時間変
化は、基準部も感圧部もほとんど同じ程度であると考え
られる。Although the seawater between the inner and outer cylinders of the pressure-sensitive part communicates with the outside through small holes, the exchange of the inner and outer seawater is very small due to the small diameter of the holes. Also, the thermal conductivity of water in the pores is much lower than that of metal. Also, the pressure-sensitive part,
Considering that seawater in contact with the inner cylinder of the pressure-sensitive part and seawater sealed between the inner and outer cylinders of the reference part are almost the same in terms of physical properties, the inner part due to external temperature fluctuations It is considered that the time change of expansion or contraction due to the temperature of the cylinder is almost the same in the reference portion and the pressure-sensitive portion.
【0027】以上をまとめると、外部の圧力変動は、感
圧部内側円筒には及ぶが、基準部内側円筒には及ばな
い。一方、外部の温度変化は、両円筒部分に同じように
及ぶ。この機構により、感圧部内側円筒の内壁の直径変
化から、基準部内側円筒内壁の直径変化を差し引いたも
のは、温度の影響を受けない純粋な圧力変化だけによる
直径変化となる。To summarize the above, external pressure fluctuations affect the inner cylinder of the pressure sensing portion, but do not affect the inner cylinder of the reference portion. On the other hand, the external temperature change equally affects both cylindrical portions. With this mechanism, the difference between the diameter change of the inner wall of the inner cylinder of the pressure sensing unit and the change of the diameter of the inner wall of the inner cylinder of the reference unit is changed by the pure pressure change which is not affected by the temperature.
【0028】以上のことを式で表すと以下のようにな
る。ある基準状態での感圧部及び基準部の内側円筒内径
をDとする。あるとき、外部海水の温度及び圧力がステ
ップ的にΔT、ΔPだけ変化したとする。このとき、感
圧部及び基準部の内側円筒内径をDs、Drとすると、The above can be expressed by the following equations. The internal diameter of the inner cylinder of the pressure-sensitive part and the reference part in a certain reference state is D. At some point, it is assumed that the temperature and pressure of the external seawater change stepwise by ΔT and ΔP. At this time, assuming that the inner diameters of the inner cylinders of the pressure-sensitive portion and the reference portion are Ds and Dr,
【0029】[0029]
【数4】 Ds=D(1+As(t)ΔT)(1−BsΔP) Dr=D(1+Ar(t)ΔT)(1−BrΔP) となる。Ds = D (1 + As (t) ΔT) (1-BsΔP) Dr = D (1 + Ar (t) ΔT) (1-BrΔP)
【0030】ここで、As(t)及びAr(t)は、感
圧部及び基準部内側円筒が過渡的に温度変化によりどの
ように膨張するかを示す係数(時間の関数)であり、最
終的には円筒構成材料の線熱膨張係数に一致するもので
ある。前述のように感圧部外側円筒に小孔があるもの
の、外から内への熱の伝わり方に大きな影響は与えな
い。従って、Here, As (t) and Ar (t) are coefficients (functions of time) indicating how the pressure-sensitive part and the reference part inner cylinder expand transiently due to temperature change. Specifically, it is the same as the coefficient of linear thermal expansion of the material constituting the cylinder. Although the pressure-sensitive portion outer cylinder has small holes as described above, it does not significantly affect how heat is transmitted from outside to inside. Therefore,
【0031】[0031]
【数5】As(t)=Ar(t)=A(t) と考えてよい。## EQU5 ## It may be considered that As (t) = Ar (t) = A (t).
【0032】また、Bs、Brは、圧力による内側円筒
の縮み方を示す係数であるが、前述のようにBrは、た
いへん小さいか0に近いので、Bs and Br are coefficients indicating how the inner cylinder contracts due to pressure. As described above, Br is very small or close to zero.
【0033】[0033]
【数6】Bs≫Br である。式〔数5〕の関係を式〔数4〕に入れることに
より、感圧部と基準部の内側円筒内径の差は、## EQU6 ## Bs≫Br. By putting the relationship of Equation [Equation 5] into Equation [Equation 4], the difference between the inner diameters of the inner cylinders of the pressure-sensitive part and the reference part becomes:
【0034】[0034]
【数7】Ds−Dr=−D(1+A(t)ΔT)(Bs
−Br)ΔP となる。A(t)の最大値が線熱膨張係数α(≒1
0-5)であり、1に比べてたいへん小さいことを考えた
上で、〔数6〕を〔数7〕に入れると、Ds−Dr = −D (1 + A (t) ΔT) (Bs
−Br) ΔP. The maximum value of A (t) is the coefficient of linear thermal expansion α (≒ 1
0 −5 ), and considering that it is much smaller than 1, when [Equation 6] is put into [Equation 7],
【0035】[0035]
【数8】Ds−Dr=−BsΔP となる。ここで、Bsは、計算や圧力変化による検定に
基づき決定できる。このように実際の観測により(Ds
−Dr)を得ることにより、温度の影響のないΔPを知
ることができる。Ds−Dr = −BsΔP Here, Bs can be determined based on a calculation or a test based on a change in pressure. Thus, the actual observation (Ds
By obtaining −Dr), ΔP free from the influence of temperature can be known.
【0036】図2は本発明に係る圧力変化計測装置の他
の実施の形態を示す図、図3は本発明に係る圧力変化計
測装置の変形例を示す図であり、71、88は外側円筒
容器、72、73は内側円筒容器、74は内蓋、75は
外蓋、76はセンサ用共振器、77は圧力伝達用小孔、
78は外部連通部、79、87はガス封入部、80は光
ファイバ、81はケーブル接続部、82はシール部、8
3は基準用共振器、84は封入部、85は封入用小孔、
86は封入用栓を示す。FIG. 2 is a diagram showing another embodiment of the pressure change measuring device according to the present invention, and FIG. 3 is a diagram showing a modified example of the pressure change measuring device according to the present invention. Containers, 72 and 73 are inner cylindrical containers, 74 is an inner lid, 75 is an outer lid, 76 is a resonator for sensor, 77 is a small hole for pressure transmission,
78 is an external communication part, 79 and 87 are gas filled parts, 80 is an optical fiber, 81 is a cable connection part, 82 is a seal part, 8
3 is a reference resonator, 84 is a sealing portion, 85 is a small hole for sealing,
Reference numeral 86 denotes a sealing plug.
【0037】この実施の形態は、中間の連結部ではな
く、基準部の連結部と反対側に光ファイバを引き出すた
めのケーブル接続部81を設けたものであり、感圧部の
内側円筒容器72、基準部の内側円筒容器73、連結部
の空間を一体にして、例えば不活性ガスを封入してい
る。同様に、内側円筒容器72、73のそれぞれの連結
部と反対側に内蓋74を設けると共に、外側円筒容器7
1、88のそれぞれの連結部と反対側に外蓋75を設け
て、内蓋74と外蓋75との間をガス封入部79、87
としている。そして、内側円筒容器72、73をそれぞ
れの両端で外側円筒容器71、88に固定することによ
り、それらの外周と外側円筒容器71、88との間に外
部連通部78又は封入部84を形成している。In this embodiment, a cable connecting portion 81 for drawing an optical fiber is provided not on the intermediate connecting portion but on the side opposite to the connecting portion of the reference portion. The inner cylindrical container 73 of the reference portion and the space of the connecting portion are integrated, and for example, an inert gas is sealed therein. Similarly, an inner lid 74 is provided on the side opposite to the connection between the inner cylindrical containers 72 and 73, and the outer cylindrical container 7
An outer lid 75 is provided on the side opposite to the connecting portion of each of the first and the 88, and a gas sealing portion 79, 87 is provided between the inner lid 74 and the outer lid 75.
And Then, by fixing the inner cylindrical containers 72 and 73 to the outer cylindrical containers 71 and 88 at both ends, an external communication portion 78 or a sealing portion 84 is formed between the outer periphery thereof and the outer cylindrical containers 71 and 88. ing.
【0038】このように本発明に係る圧力変化計測装置
は、感圧部及び基準部を外側円筒容器と内側円筒容器か
らなる二重円筒構造とし、外側円筒容器と内側円筒容器
との隙間空間を、感圧部では孔により外部と連通させ、
基準部では封入することにより、外側円筒容器の外部に
温度環境の急変があっても、その影響を排除するように
構成したものである。したがって、図1や図2に示す構
成のほか、直線状の構成ではなく図3に示すように連結
部に対し感圧部、連結部を並べて配置するなど、感圧
部、連結部、基準部の配置構成には、様々な形態を採用
することができる。As described above, in the pressure change measuring device according to the present invention, the pressure sensing portion and the reference portion have a double cylindrical structure including the outer cylindrical container and the inner cylindrical container, and the gap space between the outer cylindrical container and the inner cylindrical container is defined. , The pressure-sensitive part communicates with the outside through a hole,
The reference portion is sealed so as to eliminate the influence of a sudden change in the temperature environment outside the outer cylindrical container. Therefore, in addition to the configuration shown in FIG. 1 and FIG. 2, the pressure-sensitive portion, the connection portion, and the reference portion are not linear, but the pressure-sensitive portion and the connection portion are arranged side by side with respect to the connection portion as shown in FIG. Various configurations can be adopted for the arrangement configuration.
【0039】なお、本発明は、上記実施の形態に限定さ
れるものではなく、種々の変形が可能である。例えば上
記実施の形態では、圧力伝達用小孔や封入用小孔を2つ
設けた例で示したが、1つでも圧力伝達や封入は可能で
あり、逆に3つ以上であってもよいことはいうまでもな
い。また、海底に沈設して津波計として用いる場合につ
いて説明したが、潮位計その他の水位計として用いても
よいし、海底に限らず圧力を計測する雰囲気の中であれ
ば、ガス圧、真空度その他の計測に用いてもよい。さら
に、容器は、円筒容器に限らず二重容器であれば他の形
状の容器でも同様に適用してもよいし、レーザひずみ計
を用いた例で説明したが、差動トランスやデジタル変位
センサ等を用いて圧力変化による直径変化を計測するも
のや、ベローズの動きを拡大して差動トランスにより体
積変化を計測するものなどにも同様に適用してもよい。It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above-described embodiment, an example in which two pressure transmitting small holes and two sealing small holes are provided has been described. However, even one pressure transmitting or sealing is possible, and conversely, three or more holes may be provided. Needless to say. In addition, the case of immersion on the seabed and used as a tsunami meter has been described. However, it may be used as a tide gauge or other water level gauges, or gas pressure and vacuum It may be used for other measurements. Further, the container is not limited to a cylindrical container, but may be applied to a container of another shape as long as it is a double container, and the example using a laser strain gauge has been described, but a differential transformer or a digital displacement sensor is used. Alternatively, the present invention may be similarly applied to a device for measuring a change in diameter due to a pressure change using, for example, or a device for measuring a change in volume using a differential transformer by enlarging the movement of a bellows.
【0040】[0040]
【発明の効果】以上の説明から明らかなように、本発明
によれば、感圧部及び基準部に外側容器を設けると共
に、感圧部における外側容器には、外部と連通する少な
くとも1つないし複数の小孔を設けて該小孔を通して外
部の圧力を伝達し、基準部における外側容器には、1つ
ないし複数の小孔を設けて外部の雰囲気を導入して栓に
より封入するので、外部の圧力変化は、感圧部の内側容
器を変形させるが、基準部の内側容器には実質的な影響
を及ぼさない。一方、外部の温度変化は、感圧部と基準
部の内側容器に同じような影響を及ぼす。したがって、
感圧部の内側容器の内径変化と基準部の内側容器の内径
変化の差は、温度の影響を受けず圧力変化によるだけの
ものとして検出することができる。As is apparent from the above description, according to the present invention, the outer container is provided in the pressure-sensitive portion and the reference portion, and the outer container in the pressure-sensitive portion has at least one or more communicating with the outside. A plurality of small holes are provided to transmit external pressure through the small holes, and one or a plurality of small holes are provided in the outer container in the reference portion to introduce an external atmosphere and to be sealed with a plug. Pressure changes the inner container of the pressure sensitive part, but does not substantially affect the inner container of the reference part. On the other hand, external temperature changes have a similar effect on the pressure sensitive part and the inner container of the reference part. Therefore,
The difference between the change in the inner diameter of the inner container of the pressure-sensitive portion and the change in the inner diameter of the inner container of the reference portion can be detected as being solely due to the pressure change without being affected by the temperature.
【図1】 本発明に係る圧力変化計測装置の実施の形態
を示す図である。FIG. 1 is a diagram showing an embodiment of a pressure change measuring device according to the present invention.
【図2】 本発明に係る圧力変化計測装置の他の実施の
形態を示す図である。FIG. 2 is a diagram showing another embodiment of the pressure change measuring device according to the present invention.
【図3】 本発明に係る圧力変化計測装置の変形例を示
す図である。FIG. 3 is a diagram showing a modified example of the pressure change measuring device according to the present invention.
【図4】 レーザひずみ計の構成例を示す図である。FIG. 4 is a diagram illustrating a configuration example of a laser strain meter.
【図5】 レーザひずみ計の平面配置例を示す図であ
る。FIG. 5 is a diagram showing an example of a planar arrangement of a laser strain gauge.
【図6】 レーザひずみ計の地上側信号処理系の構成例
を示す図である。FIG. 6 is a diagram illustrating a configuration example of a ground-side signal processing system of the laser strain meter.
【図7】 レーザひずみ計の津波計への利用例を示す図
である。FIG. 7 is a diagram showing an example of using a laser strain meter for a tsunami meter.
51、67…外側円筒容器、52、53…内側円筒容
器、54…内蓋、55…光ファイバ、56…センサ用共
振器、57…圧力伝達用小孔、58…外部連通部、61
…ケーブル接続部、62…シール部、63…基準用共振
器、64…封入部、65…封入用小孔、66…封入用栓51, 67: outer cylindrical container, 52, 53: inner cylindrical container, 54: inner lid, 55: optical fiber, 56: resonator for sensor, 57: small hole for pressure transmission, 58: external communication part, 61
... Cable connection part, 62 ... Seal part, 63 ... Reference resonator, 64 ... Enclosure part, 65 ... Small hole for encapsulation, 66 ... Sealing stopper
Claims (3)
対して基準の信号を発生する基準部とを有する圧力変化
計測装置において、感圧部及び基準部に外側容器を設け
ると共に、感圧部における外側容器には、外部と連通す
る小孔を設けて該小孔を通して外部の圧力を伝達し、基
準部における外側容器は、内側容器との間に外部の媒体
を導入して封入するように構成したことを特徴とする圧
力変化計測装置。1. A pressure change measuring device having a pressure-sensitive part for detecting a pressure change and a reference part for generating a reference signal for the pressure-sensitive part, wherein an outer container is provided for the pressure-sensitive part and the reference part. In the outer container of the pressure-sensitive part, a small hole communicating with the outside is provided to transmit external pressure through the small hole, and the outer container in the reference part introduces an external medium between the outer container and the inner container. A pressure change measuring device characterized by being configured to be enclosed.
の円筒形内側容器からなることを特徴とする請求項1記
載の圧力変化計測装置。2. The pressure change measuring device according to claim 1, comprising a cylindrical outer container and a cylindrical inner container coaxial with the outer container.
の変形量を計測することを特徴とする請求項1記載の圧
力変化計測装置。3. The pressure change measuring device according to claim 1, wherein an optical resonator is attached to the inner container to measure an amount of deformation of the inner container.
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JP1765498A JP2876528B1 (en) | 1998-01-14 | 1998-01-14 | Pressure change measuring device |
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JP2876528B1 JP2876528B1 (en) | 1999-03-31 |
JPH11201841A true JPH11201841A (en) | 1999-07-30 |
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JP2007121008A (en) * | 2005-10-26 | 2007-05-17 | Ntt Infranet Co Ltd | Seismometer/tsunami meter by optical fiber and earthquake/tsunami observation system |
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