温度検知光ファイバーについて

温度感知光ファイバー 光ファイバーを使用して温度を測定する特殊なシステムです. 従来の電子センサーとは異なり、, これらのシステムは、ファイバー内を伝わる光の特性を利用します。, 温度変化に応じて変化するもの. それらは次のように機能します。 ポイントセンサー, 離散的な場所での温度測定, またはとして 分散型温度センサー (DTS), ファイバーの全長に沿って連続的な温度プロファイルを提供します. 主な利点は次のとおりです。 電磁干渉に対する耐性 (EMI), 高い電気絶縁性, 過酷な環境への適合性, 長距離を監視する機能, 従来のセンサーが実用的でない、または安全でない用途に最適です。.

光ファイバー温度センサーの仕組み?

光ファイバー温度検知 光ファイバー材料の特定の物理的特性が次のような原理に基づいています。 (ガラスのように) or the light passing through it are affected by temperature. Different technologies leverage different effects:

• Light Scattering (Raman/Brillouin): Used primarily in DTSシステム. An instrument (尋問者) sends laser pulses down the fiber. Temperature affects the molecular vibrations within the glass, which in turn affects the wavelength and intensity of the minuscule amount of light scattered back towards the instrument. By analyzing this backscattered light (specifically Raman or ブリュアン 散乱) and measuring the time it takes to return, the system can determine the temperature at each point along the fiber.
• ファイバーブラッググレーティング (FBG): These are point sensors. An FBG is a small section within the fiber core where the refractive index has been periodically altered. This grating reflects a very specific wavelength of light. 温度が変化すると, the grating expands or contracts, 反射波長をシフトする. Measuring this shift allows for precise temperature determination at the FBG’s location. Multiple FBGs at different wavelengths can be inscribed on a single fiber for multi-point sensing.
• 蛍光減衰: Used in some point sensors. A probe containing a fluorescent material is attached to the fiber ヒント. Light is sent down the fiber to excite the material, which then fluoresces (emits light). The rate at which this fluorescence decays is highly dependent on temperature. Measuring the decay time provides the temperature 読む.
• Fabry-Pérot Interferometry: Another point sensing technique where a small cavity is created at the fiber tip. Temperature changes alter the cavity length, which affects how light interferes within it. Analyzing the reflected light spectrum reveals the temperature.

Types of Fiber Optic Temperature Sensors

• ポイントセンサー: Measure temperature at a single, specific location (例えば, FBG, 蛍光, Fabry-Pérot). 複数 point sensors can often be multiplexed along a single fiber. Ideal for monitoring critical spots.
• Distributed Sensors (DTS): Use the entire length of an optical fiber as the sensor (typically using Raman or Brillouin scattering). They provide a continuous temperature profile over distances potentially spanning many kilometers. Ideal for monitoring long assets like pipelines, 電源ケーブル, トンネル, or large structures.

メリットとデメリット

よくある質問 (よくある質問)

Q1: How accurate are fiber optic temperature sensors?

あ: Accuracy varies depending on the technology, the quality of the system, 較正, and the specific application. ポイント sensors like FBGs or fluorescence probes can achieve high accuracy, often within ±0.1°C to ±1°C. DTS systems typically offer accuracies in the range of ±0.5°C to ±2°C, with spatial resolution (the ability to distinguish separate ホットスポット) typically around 0.5 に 2 メートル.

第2四半期: What is the maximum distance for DTS monitoring?

あ: 標準 DTS systems can typically monitor temperatures along fiber optic cables stretching tens of kilometers (例えば, 10 km, 30 km, 50 km以上), depending on the specific interrogator model, 繊維の品質, and desired performance (measurement time vs. 正確さ). Long-range systems are available that can extend further.

Q3: Are fiber optic sensors expensive?

あ: The initial cost, particularly for the DTS interrogator unit, can be higher than traditional thermocouples またはRTD. しかし, the cost per sensing point can become very low for DTS systems covering long distances or for multiplexed point sensors. When considering the total cost of ownership (including cabling, installation in hazardous areas, lack of EMI shielding needs, low maintenance of passive fiber), 光ファイバー can be very cost-effective for suitable applications.

Q4: Can the same fiber be used for communication and sensing?

あ: 一般的に, いいえ, especially for DTS. While standard telecom-grade fiber (single-mode or multi-mode, depending on the DTS technology) is often used, the sensing process uses different light properties (wavelengths, analysis techniques) than data transmission. It’s usually necessary to install a dedicated fiber for sensing purposes, though it can often be run alongside communication cables. Some specialized hybrid cables exist, but dedicated sensing fiber is the norm.

結論

Temperature sensing fiber optics represent a powerful and versatile technology for monitoring temperature in challenging conditions where traditional sensors struggle. Their immunity to electrical interference, ability to cover long distances (especially DTS), and options for both point and distributed measurements make them invaluable tools in industries ranging from power transmission and oil & gas to civil engineering and 火災検知. While initial costs and installation require consideration, the unique advantages often provide significant long-term benefits in safety, 信頼性, 運用効率と.

 

光ファイバー温度センサー, インテリジェント監視システム, 中国の分散型光ファイバーメーカー