Highly accurate diaphragm FBG high pressure gas sensor

Large quantities of flammable and explosive gases are often used in various production processes in the chemical and energy industries. these gases, if leaked or improperly operated, can cause serious production accidents. Therefore, in order to meet the requirement for miniaturized, highly accurate, long-term stable and large-range high pressure sensors for flammable and explosive gases in industrial production, a highly accurate diaphragm fiber Bragg grating (FBG) high pressure gas sensor is designed in this paper. In this work, the working principle of the sensor is first analyzed theoretically, the circular elastic metal diaphragm of the sensor will strain under the action of pressure load, and then the strain will be transmitted to FBG. The wavelength drift of FBG is measured to achieve the measurement of the pressure load. Then finite element simulation was carried out for the diaphragm strain of the sensor to verify the feasibility of the sensor design scheme. The traditional adhesive encapsulation is then replaced with a glass welded encapsulation to improve the durability and long-term stability of the sensor. Finally, calibration experiments was conducted on the sensor, and the experimental results were compatible with the theoretical simulation analysis. The results show that the sensor realizes long-term highly accurate measurement of pressure in a large range of 0–50 MPa, and has good static characteristics under experimental conditions.