With the development of science technology and modern industrial technology, in many fields of industrial production, the requirements of temperature measurement continue to increase. Especially in high temperature detection, such as petroleum, chemical and other high-risk environment. It asks for temperature sensors have high security, good insulation, anti-electromagnetic interference and so on. The traditional temperature sensors can’t meet application requirements. However, because of the fiber itself characteristics it can be used to measure the ambient temperature.In this paper, we use gas pressure type structure to designed a gas pressure type fiber Bragg grating temperature sensor. Using capillary connected the temperature sensing bulb with conversion chamber. We welding interlayer diaphragm on the one end of conversion chamber. the tip of transmit pressure pole rigid connected with interlayer diaphragm. The other end of the transmit pressure pole connected with the equi-intensity cantilever beam. Fixed the equi-intensity cantilever beam and bracket together by bolt. Pasted two fiber Bragg gratings on the up and down surfaces of the equi-intensity cantilever beam which have the same sensitivity coefficient. When the environment temperature changed the pressure of temperature sensing bulb will effect on the interlayer diaphragm by capillary. The transmit pressure pole pass the force on the free end of equi-intensity cantilever beam. The fiber Bragg grating will fell deflection change of equi-intensity cantilever beam. Through the differential operation between the Bragg wavelengths of sensing grating mounted the up and down surfaces of the beam, the result achieves the temperature compensated. The main research content is as follows:1. To established gas pressure type FBG temperature sensor mathematical model. Analysis the relationship between theoretical mathematical model parameters and sensor characteristics choose appropriate parameters designed the sensor components.2. According to the parameters, choose the appropriate material and the processing craft to process the sensor components. After considering various factors, we choose316L stainless steel to process equi-intensity cantilever beam and interlayer diaphragm, choose45#steel to process conversion chamber and transmit pressure pole.3. Selected the appropriate adhesive paste fiber Bragg grating to cantilever beam, and assemble the sensor components. The size of the sensor is:300mm length,280mm width,400mm height (expect the capillary tube);4. According to the selected materials, the size of the theoretical sensor sensitivity is calculated. The sensitivity in theory is10.2pm/℃.5. By the temperature testing experiment of sensor. The experimental results show that linearity of the sensor is3.59%FS, sensitivity is10.07pm/℃, hysteresis of the sensor is3.48%FS, repeatability error of the sensor is2.15%FS. |