Evaluation of the Durability and Performance of FBG-Based Sensors for Monitoring Moisture in an Aggressive Gaseous Waste Sewer Environment
Evaluation of the Durability and Performance of FBG-Based Sensors for Monitoring Moisture in an Aggressive Gaseous Waste Sewer Environment
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DOI：
10.1109/jlt.2016.2593260
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发表时间：
2017-08-15
影响因子：
4.7
通讯作者：
Grattan, Kenneth T. V.
中科院分区：
文献类型：
--
作者：
Alwis, Lourdes Shanika Malindi;Bustamante, Heriberto;Grattan, Kenneth T. V.
混凝土下水道腐蚀速率的测量需要考虑环境中的湿度，因此，其准确测量变得至关重要。引入一种新的方法来做到这一点，定制的光纤布拉格光栅（FBG）为基础的湿度传感器进行了评估，在现场检查其耐用性，时间响应，和稳定性时，在重力下水道的侵蚀性气体环境下，在一段较长的时间内使用的测量，经历高水平的湿度和硫化氢气体。探头中的临界湿度监测元件基于对湿度敏感的聚酰亚胺涂层FBG，使用校准和可再现的峰值波长偏移来响应湿度变化，在这种情况下可在下水道中操作。为了针对该环境优化器械，使用不同的材料配置了两种不同设计的探头组件，从而旨在长期提供恶劣环境下的耐用性。评估的探头设计的目的是实现对湿度的良好灵敏度，以及保护传感元件免受侵蚀性环境的影响，这使得放置在下水道中并用于交叉比较的电传感器无效。在五个月的时间内，对现场包装的传感器进行了全面评估，在此期间，传感器不断受到高但不同水平的湿度和湿硫化氢气体的影响。结果是非常令人鼓舞的，当对性能的交叉比较研究的结果进行评估时，显示出所配置的光纤传感器优于传统电传感器的上级性能。这些结果显示了光纤传感器在恶劣环境应用中长期用于湿度测量的前景。
Measurements of the rate of corrosion in concrete sewers need to take into consideration the humidity in the environment, and, thus, its accurate measurement becomes critically important. Introducing a novel approach to do so, tailored fiber Bragg grating (FBG)-based humidity sensors have been evaluated in situ to examine their durability, time response, and stability when used in measurements over an extended period of time under the aggressive gaseous environment of a gravity sewer, experiencing high levels of both humidity and hydrogen sulfide gas. The critical humidity monitoring element in the probe is based on a moisture-sensitive polyimide coated FBG, using the calibrated and reproducible peak wavelength shift in response to moisture variation, in this case operationally in the sewer. To optimize the device for this environment, two different designs of the probe assembly were configured using different material, thus aiming to provide durability in the harsh environment in the long term. The aim of the probe design evaluated was to achieve good sensitivity to humidity as well as to protect the sensing elements from the aggressive environment and which had rendered ineffective the electrical sensors placed in the sewer and used for cross comparison. A full evaluation of the packaged sensors in situ was undertaken over a period of five months, during which the sensors were constantly subjected to high, but varying levels of humidity and wet hydrogen sulfide gas. The results are highly encouraging, showing superior performance of the configured fiber optic sensors used over a conventional electrical sensor when the results of the cross-comparison study of the performance were evaluated. These outcomes show a promising future for optical fiber sensors to be employed for measurement of humidity in the long term in harsh environmental applications such as this.