The fiber Bragg grating (FBG) sensing technology is used to dynamically monitor multiple parameters of railway switch machine poles, including time of movement, direction and quantity of loading and locking force, and states of loading resistance. This paper presents the design and implementation of a railway switch pole strain on-line monitoring system based on the FBG stress-sensibilized monitor for a Siemens S700K switch machine. The ring shape FBG strain gauge and stress-sensibilized methods significantly increased the monitoring sensitivity. Installing approaches adapted the harsh environment in the railway application. The monitoring results showed the high sensitivity and high reliability of this monitoring system. This application provides a long-term and on-line detecting method which could meet railway switch condition monitoring demands of more than 100,000 switch machines in the country.

The fiber Bragg grating (FBG) sensing technology was used to monitor the situation of a crevice of the continuous beam joint and rails near rail expansion devices on a viaduct of the urban railway. The monitoring items consisted of the rail temperature, rail displacement, viaduct beam displacement, and strain of sliding rail in the rail expansion device section. The strain sensor was a prefabricate FBG strain gauge, the displacement sensor with different scales used an FBG stress ring, and the FBG of the temperature sensor was pre-drawn and fixed in a metal tube. Compensation sensors were used to balance environmental temperature changes. All FBGs were suspended adhered, therefore the chirped phenomenon of the FBG reflection peak was avoided, and the measurement accuracy was improved. The monitoring results matched to the manual test and theoretical estimation.

应用于煤气化炉的蓝宝石光纤宽谱温度监测系统解决了蓝宝石光纤测温技术无法同时监测高温和低温状态的问题。在煤气化炉点火和烘炉的低温段，将微弱的热辐射信号放大，采用插值法得到低温值；在高温段，采用比色测温法进行精确的温度监测。系统利用蓝宝石单晶光纤和耐高温耐冲刷合金管作为蓝宝石光纤的护套，以适应煤气炉内的高温和冲刷的恶劣环境，并采用光纤高压隔离器件，将蓝宝石光纤导出压力为5 MPa的炉外。经标定和温度实测，系统的测量范围为200 ℃～1600 ℃，可分辨温度达1 ℃，高温段温度测量精度达0.5%。