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JPH01189529A - Shape memory alloy optical fiber temperature detector - Google Patents

Shape memory alloy optical fiber temperature detector

Info

Publication number
JPH01189529A
JPH01189529A JP63014045A JP1404588A JPH01189529A JP H01189529 A JPH01189529 A JP H01189529A JP 63014045 A JP63014045 A JP 63014045A JP 1404588 A JP1404588 A JP 1404588A JP H01189529 A JPH01189529 A JP H01189529A
Authority
JP
Japan
Prior art keywords
optical fiber
light
memory alloy
shape memory
emitting element
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
Application number
JP63014045A
Other languages
Japanese (ja)
Inventor
Shusaku Umeda
梅田 秀作
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Furukawa Electric Co Ltd
Original Assignee
Furukawa Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Furukawa Electric Co Ltd filed Critical Furukawa Electric Co Ltd
Priority to JP63014045A priority Critical patent/JPH01189529A/en
Publication of JPH01189529A publication Critical patent/JPH01189529A/en
Pending legal-status Critical Current

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  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Light Guides In General And Applications Therefor (AREA)

Abstract

PURPOSE:To detect temp. with high accuracy by eliminating erroneous operation due to the variation of the emitting quantity of light from a light emitting element or the variation of the sensitivity of a photodetector, by comparing the output of a monitoring photodetector with the output of a measuring photodetector to detect abnormal temp. CONSTITUTION:A temp. sensor 2 using a shape memory alloy is provided at one or more measuring points and a measuring optical fiber 1 is bent by the shape change of the sensor 2 at the time of predetermined temp. to increase light transmission loss and temp. is detected. A monitoring fiber 4 is arranged in the vicinity of a light emitting element 3 projecting energy on the optical fiber 1 and the quantity of light from the light emitting element 3 transmitted by the optical fiber 4 is measured by a monitoring photodetector 6 having the same temp. sensitivity characteristic as a measuring photodetector 5 receiving the light of the optical fiber 1 and the outputs of the photodetectors 5, 6 are compared to detect temp. The current of the light emitting element is increased or decreased on the basis of the output of the difference between the output voltage of the photodetector 6 and reference voltage so as to make the output of the photodetector 6 constant and the emission quantity of the light from the light emitting element 3 due to the variation of atmospheric temp. is automatically compensated.

Description

【発明の詳細な説明】 (産業上の利用分野) 本発明は変圧器内、制御盤内、各種設備の底部といっ・
た人目にふれないか或はふれにくい場所の異常温度を検
知するのに使用される形状記憶合金光ファイバ温度検知
器に関するものである。
[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to transformers, control panels, and the bottom of various equipment.
The present invention relates to a shape memory alloy optical fiber temperature sensor used to detect abnormal temperatures in places that are hidden or difficult to access.

(従来技術) 従来使用されている形状記憶合金光ファイバ温度検知器
は第5図のように、発光素子(LED)からの光を伝送
する光ファイバAの被測定点に、形状記憶合金を用いた
温度センサB、Cを設置してなる。この温度センサB、
Cは第3図のように光ファイバAの上方にそれと直交状
に形状記憶合金棒Eを配置し、その形状記憶合金棒Eは
低温時は第3図の実線のように一端側が上方に曲げられ
ており、周囲温度が上昇して臨界温度を越えると第3図
の鎖線で示すように下方に形状変化して直線状になり、
光ファイバAを同図の鎖線の位置に押し曲げるようにし
である。この押し曲げにより光ファイバAの光伝送ロス
が増加しく例えば第4図のように15cmの範囲で7c
m曲げると3dB伝送ロスが増加する)、その増加を受
光素子(フォトダイオード:PD)により電圧変換し、
その電圧が予め設定されている基準値を越えると温度上
昇したものとして感知されるようにしである、なおその
感知に基づいて警報を発生させたり、リレーを作動させ
たりするようにしである。
(Prior art) As shown in Figure 5, the conventionally used shape memory alloy optical fiber temperature sensor uses a shape memory alloy at the measurement point of the optical fiber A that transmits light from a light emitting element (LED). Temperature sensors B and C were installed. This temperature sensor B,
As shown in Figure 3, a shape memory alloy rod E is placed above the optical fiber A and perpendicular to it, and when the temperature is low, one end of the shape memory alloy rod E is bent upward as shown by the solid line in Figure 3. When the ambient temperature rises and exceeds the critical temperature, the shape changes downward and becomes straight, as shown by the chain line in Figure 3.
The optical fiber A is pressed and bent to the position indicated by the chain line in the figure. This pushing and bending increases the optical transmission loss of optical fiber A. For example, as shown in Figure 4, 7c
3 dB transmission loss increases when bent), the increase is converted into voltage by a light receiving element (photodiode: PD),
When the voltage exceeds a preset reference value, it is detected as an increase in temperature, and based on this detection, an alarm is generated or a relay is activated.

(従来技術の問題点) 従来技術では受発光素子としてLEDやFDなどを使用
しているため、それらの寿命や外気温の変動などにより
発光量が変動したり、受光感度が変動したりすることが
ある。このため予めその変動分を見込んで基準値を設定
したり、季節によって基準値を変えたりする必要があり
、取扱いが面倒であった。
(Problems with conventional technology) Since conventional technology uses LEDs, FDs, etc. as light receiving and emitting elements, the amount of light emitted and the light receiving sensitivity fluctuate depending on their lifespan and fluctuations in outside temperature. There is. For this reason, it is necessary to set the reference value in advance by taking into account the variation, or to change the reference value depending on the season, which is cumbersome to handle.

(発明の目的) 本発明の目的は外気温の変動による影響が少ない形状記
憶合金光ファイバ温度検知器と、外気温の変動による発
光素子の発光量の変動を自動的に補償できる形状記憶合
金光ファイバ温酸検知塁とを実現することにある。
(Object of the Invention) The object of the present invention is to provide a shape memory alloy optical fiber temperature sensor that is less affected by fluctuations in outside temperature, and a shape memory alloy optical fiber that can automatically compensate for fluctuations in the amount of light emitted from a light emitting element due to fluctuations in outside temperature. The purpose is to realize a fiber warm acid detection base.

(問題点を解決するための手段) 本件発明のうち第1の形状記憶合金光ファイバ温度検知
器は、1箇所乃至2箇所以上の測定点に形状記憶合金を
用いた温度センサ2を設け、予め設定された所定温度以
上になったときに同センサ2の形状記憶合金の形状変化
により測定用光ファイバ1を屈曲して同光ファイバ1の
光伝送ロスを増加させて温度検知するようにした光ファ
イバ温度検知器において、測定用光ファイバ1に光エネ
ルギーを投射する発光素子3の近くにモニタ用光ファイ
バ4を配置し、同光ファイバ4により伝送される発光素
子3の光量を測定用光ファイバ1の光を受ける測定用受
光素子5と同じ温度感度特性を有するモニタ用受光素子
6で測定し、モニタ用受光素子6の出力と測定用受光素
子5の出力とを比較して温度を検知するようにしたこと
を特徴とするものである。
(Means for Solving the Problems) The first shape memory alloy optical fiber temperature sensor of the present invention is provided with a temperature sensor 2 using a shape memory alloy at one or more measurement points, and A light whose temperature is detected by bending the measuring optical fiber 1 by changing the shape of the shape memory alloy of the sensor 2 when the temperature reaches a predetermined temperature or higher, thereby increasing the optical transmission loss of the optical fiber 1. In the fiber temperature sensor, a monitoring optical fiber 4 is placed near the light emitting element 3 that projects optical energy onto the measuring optical fiber 1, and the amount of light from the light emitting element 3 transmitted by the optical fiber 4 is measured by the measuring optical fiber 4. The temperature is detected by comparing the output of the monitoring light receiving element 6 and the output of the measuring light receiving element 5. It is characterized by the following.

本件発明のうち第2の形状記憶合金光ファイバ温度検知
器は、上記した第1の形状記憶合金光ファイバ温度検知
器において、モニタ用受光素子6の出力電圧と基準電圧
との差の出力により、モニタ用受光素子6の出力が一定
となるように発光素子3の電流を増減するようにしたこ
とを特徴とするものである。
The second shape memory alloy optical fiber temperature sensor of the present invention is the same as the first shape memory alloy optical fiber temperature sensor described above, based on the output of the difference between the output voltage of the monitoring light receiving element 6 and the reference voltage. This device is characterized in that the current of the light emitting element 3 is increased or decreased so that the output of the monitoring light receiving element 6 is constant.

(発明の作用) 第1図は第1の発明の形状記憶合金光ファイバ温度検知
器である。
(Operation of the Invention) FIG. 1 shows a shape memory alloy optical fiber temperature sensor according to the first invention.

これは発光素子3からの光が測定用光ファイバ1、モニ
タ用光ファイバ4により、夫々測定用受光素子5、モニ
タ用受光素子6に導かれ、夫々の光量が受光素子5.6
により電流に変換される。
This is because the light from the light emitting element 3 is guided to the measuring light receiving element 5 and the monitoring light receiving element 6 through the measuring optical fiber 1 and the monitoring optical fiber 4, respectively, and the amount of light is determined by the light receiving element 5 and the monitoring light receiving element 6, respectively.
is converted into electric current by

この変換された青電流の差が可変抵抗VR2、抵抗R3
により電圧に変換され、差動アンプAmp3により増幅
されて検出される。
The difference between this converted blue current is the variable resistor VR2 and the resistor R3.
The voltage is converted into a voltage by the differential amplifier Amp3, and the voltage is amplified and detected by the differential amplifier Amp3.

この状態で周囲温度が上昇して臨界温度を越えると温度
センサ2が作動する。即ち、温度センサ2の記憶合金棒
E(第3図)が第3図の鎖線で示すように直線状に形状
変化し、測定用光ファイバ1が同図の鎖線の位置に押し
曲げられ七光伝送ロスが増加し、モニタ用受光素子6と
測定用受光素子5との電圧差が大きくなるので、温度セ
ンサ2の動作を差動アンプAmp3の出力電圧により検
知することができ、異常温度を検知できる。
In this state, when the ambient temperature rises and exceeds the critical temperature, the temperature sensor 2 is activated. That is, the memory alloy rod E (FIG. 3) of the temperature sensor 2 changes its shape linearly as shown by the chain line in FIG. Since the transmission loss increases and the voltage difference between the monitoring light receiving element 6 and the measuring light receiving element 5 increases, the operation of the temperature sensor 2 can be detected by the output voltage of the differential amplifier Amp3, and abnormal temperatures can be detected. can.

第2図は第2の形状記憶合金光ファイバ温度検知器であ
る。これは第1の形状記憶合金光ファイバ温度検知器と
同様にして異常温度が検知され、更にトランジスタTR
Iのベース電圧を僅か変化させるだけ発光素子3に流れ
る電流を増減させて発光素子3の発光量を変えるように
したものである。即ち、トランジスタTRIのベース電
圧をモニタ用受光素子6の出力電圧と可変抵抗VR4、
抵抗R5の比率により決定される一定電圧との差によっ
て増減させることで発光素子3の発光量が自動的に補償
され、発光量の変動が小さくなる。
FIG. 2 shows a second shape memory alloy optical fiber temperature sensor. This detects abnormal temperature in the same manner as the first shape memory alloy optical fiber temperature sensor, and furthermore, the transistor TR
The amount of light emitted by the light emitting element 3 is changed by increasing or decreasing the current flowing through the light emitting element 3 by slightly changing the base voltage of I. That is, the base voltage of the transistor TRI is determined by the output voltage of the monitoring light receiving element 6 and the variable resistor VR4,
The amount of light emitted by the light emitting element 3 is automatically compensated by increasing or decreasing the voltage depending on the difference from the constant voltage determined by the ratio of the resistor R5, and the fluctuation in the amount of light emitted is reduced.

変動の比率は増幅器Ampl、Amp2の利得とバイア
スにより調整できる。
The ratio of fluctuation can be adjusted by the gain and bias of the amplifiers Ampl and Amp2.

(発明の実施例) 第1図は第1の発明の実施例、第2図は第2の発明の実
施例である。
(Embodiments of the Invention) FIG. 1 shows an embodiment of the first invention, and FIG. 2 shows an embodiment of the second invention.

これらの図においてVfは発光ダイオードLEDの電源
、RLは電流制限用の抵抗である。
In these figures, Vf is a power source for the light emitting diode LED, and RL is a current limiting resistor.

3は発光素子であり、図では発光ダイオードLEDが使
用されている。
3 is a light emitting element, and in the figure, a light emitting diode LED is used.

1は測定用光ファイバ、4はモニタ用光ファイバであり
、これらには例えばプラスチック光ファイバ等が使用さ
れる。
1 is an optical fiber for measurement, and 4 is an optical fiber for monitoring, for example, plastic optical fibers are used for these.

2は温度センサーであり、これは第3図のものと同じく
形状記憶合金を用いたものである。
2 is a temperature sensor, which uses a shape memory alloy like the one shown in FIG.

5は・測定用受光素子、6はモニタ用受光素子であり、
図ではこれらとしてフォトダイオードPDが使用されて
いるが、これは特にLEDの発光波長に対して有効な感
度があればフォトトランジスタでも、光電管でもよい。
5 is a light receiving element for measurement, 6 is a light receiving element for monitoring,
In the figure, a photodiode PD is used as these, but it may be a phototransistor or a phototube as long as it has effective sensitivity particularly to the emission wavelength of the LED.

第2図のTRIはトランジスタであり、これは発光素子
3の電流制御用であり、トランジスタTR1を直利に接
続されている。
TRI in FIG. 2 is a transistor, which is used to control the current of the light emitting element 3, and is directly connected to the transistor TR1.

VRI〜VR5は可変抵抗器、R3、R5は抵抗、Am
pl、A m p 3は差動増幅器、Amp2は増幅器
である。
VRI to VR5 are variable resistors, R3 and R5 are resistors, Am
pl and A m p3 are differential amplifiers, and Amp2 is an amplifier.

(発明の効果) 本件出願のうち第1の発明はモニタ用受光素子6の出力
と測定用受光素子5の出力とを比較して異常温度を検知
するものであるため、発光素子の発光量が変動しても、
受光素子の感度が変動しても、モニタ側もセンサー側も
同じ比率で電圧が変動するので誤動作が生じない。
(Effect of the invention) The first invention of the present application detects abnormal temperature by comparing the output of the monitor light receiving element 6 and the output of the measuring light receiving element 5, so that the amount of light emitted by the light emitting element is Even if it fluctuates,
Even if the sensitivity of the light-receiving element fluctuates, the voltage on both the monitor and sensor sides fluctuates at the same rate, so malfunctions do not occur.

本件出願のうち第2の発明t±第1の発明と同じ効果が
あり、更にモニタ用受光素子6の出力と基準電圧との差
の出力によりモニタ用受光素子6の光出力が一定となる
ように発光素子3の電流が増減するので、発光素子の温
度変化による発光量の変動が自動的に補償され、その変
動が少なく、精度の高い温度検知が可能となる。
The second invention of the present application has the same effect as the first invention, and furthermore, the light output of the monitor light-receiving element 6 is made constant by the output of the difference between the output of the monitor light-receiving element 6 and the reference voltage. Since the current of the light emitting element 3 increases and decreases, fluctuations in the amount of light emitted by the light emitting element due to temperature changes are automatically compensated for, and the fluctuation is small, making it possible to detect temperature with high accuracy.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の形状記憶合金光ファイバ温度検知器の
一例を示す説明図、第2図は光量補償回路を備えた形状
記憶合金光ファイバ温度検知器の一例を示す説明図、第
3図は形状記憶合金を用いた温度センサの一例を示す側
面図、第4図は同センサの光伝送ロスの説明図、第5図
は従来の形状記憶合金光ファイバ温度検知器の一例を示
す説明図である。 1は測定用光ファイバ 2は温度センサ 3は発光素子 4はモニタ用光ファイバ 5は測定用受光素子 6はモニタ用受光素子
FIG. 1 is an explanatory diagram showing an example of a shape memory alloy optical fiber temperature sensor of the present invention, FIG. 2 is an explanatory diagram showing an example of a shape memory alloy optical fiber temperature sensor equipped with a light intensity compensation circuit, and FIG. 4 is a side view showing an example of a temperature sensor using a shape memory alloy, FIG. 4 is an explanatory diagram of the optical transmission loss of the sensor, and FIG. 5 is an explanatory diagram showing an example of a conventional shape memory alloy optical fiber temperature sensor. It is. 1 is an optical fiber for measurement 2 is a temperature sensor 3 is a light emitting element 4 is an optical fiber for monitoring 5 is a light receiving element for measurement 6 is a light receiving element for monitoring

Claims (2)

【特許請求の範囲】[Claims] (1)一箇所乃至二箇所以上の測定点に形状記憶合金を
用いた温度センサ2を設け、予め設定された所定温度以
上になると同センサ2の形状記憶合金の形状変化により
測定用光ファイバ1を屈曲させて同光ファイバ1の光伝
送ロスを増加せ、その光伝送ロスの変化から温度変化を
検知するようにした形状記憶合金光ファイバ温度検知器
において、測定用光ファイバ1に光を投射する発光素子
3の近くにモニタ用光ファイバ4を配置し、同光ファイ
バ4により伝送される発光素子3からの光量を、測定用
光ファイバ1から光を受ける測定用受光素子5と同じ温
度感度特性を有するモニタ用受光素子6で測定し、モニ
タ用受光素子6の出力と測定用受光素子5の出力とを比
較して異常温度を検知するようにしたことを特徴とする
形状記憶合金光ファイバ温度検知器。
(1) A temperature sensor 2 using a shape memory alloy is provided at one or more measurement points, and when the temperature exceeds a preset temperature, the shape of the shape memory alloy of the sensor 2 changes, causing the measuring optical fiber 1 to In the shape memory alloy optical fiber temperature sensor, which increases the optical transmission loss of the optical fiber 1 by bending the optical fiber 1, and detects temperature changes from the change in the optical transmission loss, light is projected onto the measuring optical fiber 1. A monitoring optical fiber 4 is placed near the light-emitting element 3 for measurement, and the amount of light from the light-emitting element 3 transmitted through the same optical fiber 4 has the same temperature sensitivity as the measurement light-receiving element 5 that receives light from the measurement optical fiber 1. A shape memory alloy optical fiber characterized in that abnormal temperature is detected by measuring with a monitoring light receiving element 6 having a characteristic and comparing the output of the monitoring light receiving element 6 and the output of the measuring light receiving element 5. Temperature detector.
(2)一箇所乃至二箇所以上の測定点に形状記憶合金を
用いた温度センサ2を設け、予め設定された所定温度以
上になると同センサ2の形状記憶合金の形状変化により
測定用光ファイバ1を屈曲させて同光ファイバ1の光伝
送ロスを増加せ、その光伝送ロスの変化から温度変化を
検知するようにした形状記憶合金光ファイバ温度検知器
において、測定用光ファイバ1に光を投射する発光素子
3の近くにモニタ用光ファイバ4を配置し、同光ファイ
バ4により伝送される発光素子3の光量を、測定用光フ
ァイバ1からの光を受ける測定用受光素子5と同じ温度
感度特性を有するモニタ用受光素子6で測定し、モニタ
用受光素子6の出力と測定用受光素子5の出力とを比較
して異常温度を検知すると共に、モニタ用受光素子6の
出力と基準電圧との差の出力によりモニタ用受光素子6
の光出力が一定となるように発光素子3の電流を増減す
るようにしたことを特徴とする形状記憶合金光ファイバ
温度検知器。
(2) A temperature sensor 2 using a shape memory alloy is provided at one or more measurement points, and when the temperature exceeds a preset temperature, the shape of the shape memory alloy of the sensor 2 changes and the measurement optical fiber 1 is In the shape memory alloy optical fiber temperature sensor, which increases the optical transmission loss of the optical fiber 1 by bending the optical fiber 1, and detects temperature changes from the change in the optical transmission loss, light is projected onto the measuring optical fiber 1. A monitoring optical fiber 4 is placed near the light emitting element 3 to be measured, and the amount of light from the light emitting element 3 transmitted through the same optical fiber 4 is adjusted to the same temperature sensitivity as the measuring light receiving element 5 that receives light from the measuring optical fiber 1. Abnormal temperature is detected by comparing the output of the monitor light-receiving element 6 and the output of the measurement light-receiving element 5, and also compares the output of the monitor light-receiving element 6 with the reference voltage. The monitor light receiving element 6
A shape memory alloy optical fiber temperature sensor characterized in that the current of the light emitting element 3 is increased or decreased so that the light output of the light emitting element 3 is constant.
JP63014045A 1988-01-25 1988-01-25 Shape memory alloy optical fiber temperature detector Pending JPH01189529A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP63014045A JPH01189529A (en) 1988-01-25 1988-01-25 Shape memory alloy optical fiber temperature detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP63014045A JPH01189529A (en) 1988-01-25 1988-01-25 Shape memory alloy optical fiber temperature detector

Publications (1)

Publication Number Publication Date
JPH01189529A true JPH01189529A (en) 1989-07-28

Family

ID=11850135

Family Applications (1)

Application Number Title Priority Date Filing Date
JP63014045A Pending JPH01189529A (en) 1988-01-25 1988-01-25 Shape memory alloy optical fiber temperature detector

Country Status (1)

Country Link
JP (1) JPH01189529A (en)

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